How well do simulated last glacial maximum tropical temperatures constrain equilibrium climate sensitivity?

NASA Astrophysics Data System (ADS)

Hopcroft, Peter O.; Valdes, Paul J.

2015-07-01

Previous work demonstrated a significant correlation between tropical surface air temperature and equilibrium climate sensitivity (ECS) in PMIP (Paleoclimate Modelling Intercomparison Project) phase 2 model simulations of the last glacial maximum (LGM). This implies that reconstructed LGM cooling in this region could provide information about the climate system ECS value. We analyze results from new simulations of the LGM performed as part of Coupled Model Intercomparison Project (CMIP5) and PMIP phase 3. These results show no consistent relationship between the LGM tropical cooling and ECS. A radiative forcing and feedback analysis shows that a number of factors are responsible for this decoupling, some of which are related to vegetation and aerosol feedbacks. While several of the processes identified are LGM specific and do not impact on elevated CO2 simulations, this analysis demonstrates one area where the newer CMIP5 models behave in a qualitatively different manner compared with the older ensemble. The results imply that so-called Earth System components such as vegetation and aerosols can have a significant impact on the climate response in LGM simulations, and this should be taken into account in future analyses.

Climate system properties determining the social cost of carbon

NASA Astrophysics Data System (ADS)

Otto, Alexander; Todd, Benjamin J.; Bowerman, Niel; Frame, David J.; Allen, Myles R.

2013-06-01

The choice of an appropriate scientific target to guide global mitigation efforts is complicated by uncertainties in the temperature response to greenhouse gas emissions. Much climate policy discourse has been based on the equilibrium global mean temperature increase following a concentration stabilization scenario. This is determined by the equilibrium climate sensitivity (ECS) which, in many studies, shows persistent, fat-tailed uncertainty. However, for many purposes, the equilibrium response is less relevant than the transient response. Here, we show that one prominent policy variable, the social cost of carbon (SCC), is generally better constrained by the transient climate response (TCR) than by the ECS. Simple analytic expressions show the SCC to be directly proportional to the TCR under idealized assumptions when the rate at which we discount future damage equals 2.8%. Using ensemble simulations of a simple climate model we find that knowing the true value of the TCR can reduce the relative uncertainty in the SCC substantially more, up to a factor of 3, than knowing the ECS under typical discounting assumptions. We conclude that the TCR, which is better constrained by observations, less subject to fat-tailed uncertainty and more directly related to the SCC, is generally preferable to the ECS as a single proxy for the climate response in SCC calculations.

Updated estimates of the climate response to emissions and their policy implications (Invited)

NASA Astrophysics Data System (ADS)

Allen, M. R.; Otto, A.; Stocker, T. F.; Frame, D. J.

2013-12-01

We review the implications of observations of the global energy budget over recent decades, particularly the 'warming hiatus' period over the 2000s, for key climate system properties including equilibrium climate sensitivity (ECS), transient climate response (TCR) and transient climate response to cumulative carbon emissions (TCRE). We show how estimates of the upper bound of ECS remain, as ever, sensitive to prior assumptions and also how ECS, even if it were better constrained, would provide much less information about the social cost of carbon than TCR or TCRE. Hence the excitement over recent, apparently conflicting, estimates of ECS, is almost entirely misplaced. Of greater potential policy significance is the fact that recent observations imply a modest (of order 25%) downward revision in the upper bound and most likely values of TCR and TCRE, as compared to some, but not all, of the estimates published in the mid-2000s. This is partly due to the recent reduced rate of warming, and partly due to revisions in estimates of total anthropogenic forcing to date. Both of these developments may turn out to be short-lived, so the policy implications of this modest revision in TCR/TCRE should not be over-sold: nevertheless, it is interesting to explore what they are. The implications for climate change adaptation of a 25% downward revision in TCR and TCRE are minimal, being overshadowed by uncertainty due to internal variability and non-CO2 climate forcings over typical timescales for adaptation planning. We introduce a simple framework for assessing the implications for mitigation in terms of timing of peak emissions average rates of emission reduction required to avoid specific levels of peak warming. We show that, as long as emissions continue to increase approximately exponentially, the implications for mitigation of any revisions in the climate response are surprisingly small.

A revised energy-balance framework for the Earth

NASA Astrophysics Data System (ADS)

Dessler, A. E.

2017-12-01

Some of the most important conclusions of climate science are based on energy balance calculations, in which solar energy absorbed by the Earth system is set equal to infrared energy radiated to space. Traditionally, energy radiated to space is assumed to be proportional to surface temperature. We show here problems with this framework, including potential biases in estimates of climate sensitivity based on the 20th-century historical record. This could potentially explain why estimates of equilibrium climate sensitivity (ECS) using observations over the 20th century yield values lower than other estimates. We then present a modified version of the energy balance framework in which energy radiated to space is assumed to be proportional to tropical atmospheric temperature. We use this new framework to estimate ECS and obtain an estimate of 3°C, with a likely range (66% confidence interval) of 2.2-4.1°C.

Multi-scale enhancement of climate prediction over land by increasing the model sensitivity to vegetation variability in EC-Earth

NASA Astrophysics Data System (ADS)

Alessandri, A.; Catalano, F.; De Felice, M.; van den Hurk, B.; Doblas-Reyes, F. J.; Boussetta, S.; Balsamo, G.; Miller, P. A.

2016-12-01

The European consortium earth system model (EC-Earth; http://www.ec-earth.org) has been recently developed to include the dynamics of vegetation. In its original formulation, vegetation variability is simply operated by the Leaf Area Index (LAI), which affects climate basically by changing the vegetation physiological resistance to evapotranspiration. This coupling has been found to have only a weak effect on the surface climate modeled by EC-Earth. In reality, the effective sub-grid vegetation fractional coverage will vary seasonally and at interannual time-scales in response to leaf-canopy growth, phenology and senescence. Therefore it affects biophysical parameters such as the albedo, surface roughness and soil field capacity. To adequately represent this effect in EC-Earth, we included an exponential dependence of the vegetation cover on the LAI. By comparing two sets of simulations performed with and without the new variable fractional-coverage parameterization, spanning from centennial (20th Century) simulations and retrospective predictions to the decadal (5-years), seasonal and weather time-scales, we show for the first time a significant multi-scale enhancement of vegetation impacts in climate simulation and prediction over land. Particularly large effects at multiple time scales are shown over boreal winter middle-to-high latitudes over Canada, West US, Eastern Europe, Russia and eastern Siberia due to the implemented time-varying shadowing effect by tree-vegetation on snow surfaces. Over Northern Hemisphere boreal forest regions the improved representation of vegetation cover tends to correct the winter warm biases, improves the climate change sensitivity, the decadal potential predictability as well as the skill of forecasts at seasonal and weather time-scales. Significant improvements of the prediction of 2m temperature and rainfall are also shown over transitional land surface hot spots. Both the potential predictability at decadal time-scale and seasonal-forecasts skill are enhanced over Sahel, North American Great Plains, Nordeste Brazil and South East Asia, mainly related to improved performance in the surface evapotranspiration.

State-Dependence of the Climate Sensitivity in Earth System Models of Intermediate Complexity

NASA Astrophysics Data System (ADS)

Pfister, Patrik L.; Stocker, Thomas F.

2017-10-01

Growing evidence from general circulation models (GCMs) indicates that the equilibrium climate sensitivity (ECS) depends on the magnitude of forcing, which is commonly referred to as state-dependence. We present a comprehensive assessment of ECS state-dependence in Earth system models of intermediate complexity (EMICs) by analyzing millennial simulations with sustained 2×CO2 and 4×CO2 forcings. We compare different extrapolation methods and show that ECS is smaller in the higher-forcing scenario in 12 out of 15 EMICs, in contrast to the opposite behavior reported from GCMs. In one such EMIC, the Bern3D-LPX model, this state-dependence is mainly due to the weakening sea ice-albedo feedback in the Southern Ocean, which depends on model configuration. Due to ocean-mixing adjustments, state-dependence is only detected hundreds of years after the abrupt forcing, highlighting the need for long model integrations. Adjustments to feedback parametrizations of EMICs may be necessary if GCM intercomparisons confirm an opposite state-dependence.

The influence of internal variability on Earth's energy balance framework and implications for estimating climate sensitivity

NASA Astrophysics Data System (ADS)

Dessler, Andrew E.; Mauritsen, Thorsten; Stevens, Bjorn

2018-04-01

Our climate is constrained by the balance between solar energy absorbed by the Earth and terrestrial energy radiated to space. This energy balance has been widely used to infer equilibrium climate sensitivity (ECS) from observations of 20th-century warming. Such estimates yield lower values than other methods, and these have been influential in pushing down the consensus ECS range in recent assessments. Here we test the method using a 100-member ensemble of the Max Planck Institute Earth System Model (MPI-ESM1.1) simulations of the period 1850-2005 with known forcing. We calculate ECS in each ensemble member using energy balance, yielding values ranging from 2.1 to 3.9 K. The spread in the ensemble is related to the central assumption in the energy budget framework: that global average surface temperature anomalies are indicative of anomalies in outgoing energy (either of terrestrial origin or reflected solar energy). We find that this assumption is not well supported over the historical temperature record in the model ensemble or more recent satellite observations. We find that framing energy balance in terms of 500 hPa tropical temperature better describes the planet's energy balance.

Earths Climate Sensitivity: Apparent Inconsistencies in Recent Assessments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Stephen E.; Charlson, Robert J.; Kahn, Ralph

Earth's equilibrium climate sensitivity (ECS) and forcing of Earth's climate system over the industrial era have been re-examined in two new assessments: the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and a study by Otto et al. (2013). The ranges of these quantities given in these assessments and also in the Fourth (2007) IPCC Assessment are analyzed here within the framework of a planetary energy balance model, taking into account the observed increase in global mean surface temperature over the instrumental record together with best estimates of the rate of increase of planetary heat content.more » This analysis shows systematic differences among the several assessments and apparent inconsistencies within individual assessments. Importantly, the likely range of ECS to doubled CO₂ given in AR5, 1.5–4.5 K/(3.7 W m⁻²) exceeds the range inferred from the assessed likely range of forcing, 1.2–2.9 K/(3.7 W m⁻²), where 3.7 W ⁻² denotes the forcing for doubled CO₂. Such differences underscore the need to identify their causes and reduce the underlying uncertainties. Explanations might involve underestimated negative aerosol forcing, overestimated total forcing, overestimated climate sensitivity, poorly constrained ocean heating, limitations of the energy balance model, or a combination of effects.« less

Earths Climate Sensitivity: Apparent Inconsistencies in Recent Assessments

DOE PAGES

Schwartz, Stephen E.; Charlson, Robert J.; Kahn, Ralph; ...

2014-12-08

Earth's equilibrium climate sensitivity (ECS) and forcing of Earth's climate system over the industrial era have been re-examined in two new assessments: the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and a study by Otto et al. (2013). The ranges of these quantities given in these assessments and also in the Fourth (2007) IPCC Assessment are analyzed here within the framework of a planetary energy balance model, taking into account the observed increase in global mean surface temperature over the instrumental record together with best estimates of the rate of increase of planetary heat content.more » This analysis shows systematic differences among the several assessments and apparent inconsistencies within individual assessments. Importantly, the likely range of ECS to doubled CO₂ given in AR5, 1.5–4.5 K/(3.7 W m⁻²) exceeds the range inferred from the assessed likely range of forcing, 1.2–2.9 K/(3.7 W m⁻²), where 3.7 W ⁻² denotes the forcing for doubled CO₂. Such differences underscore the need to identify their causes and reduce the underlying uncertainties. Explanations might involve underestimated negative aerosol forcing, overestimated total forcing, overestimated climate sensitivity, poorly constrained ocean heating, limitations of the energy balance model, or a combination of effects.« less

Urban impact on air quality in RegCM/CAMx couple for MEGAPOLI project - high resolution sensitivity study

NASA Astrophysics Data System (ADS)

Halenka, T.; Huszar, P.; Belda, M.

2010-09-01

Recent studies show considerable effect of atmospheric chemistry and aerosols on climate on regional and local scale. For the purpose of qualifying and quantifying the magnitude of climate forcing due to atmospheric chemistry/aerosols on regional scale, the development of coupling of regional climate model and chemistry/aerosol model was started on the Department of Meteorology and Environmental Protection, Charles University, Prague, for the EC FP6 Project QUANTIFY and EC FP6 Project CECILIA. For this coupling, existing regional climate model and chemistry transport model have been used at very high resolution of 10km grid. Climate is calculated using RegCM while chemistry is solved by CAMx. The experiments with the couple have been prepared for EC FP7 project MEGAPOLI assessing the impact of the megacities and industrialized areas on climate. Meteorological fields generated by RCM drive CAMx transport, chemistry and a dry/wet deposition. A preprocessor utility was developed for transforming RegCM provided fields to CAMx input fields and format. New domain have been settled for MEGAPOLI purpose in 10km resolution including all the European "megacities" regions, i.e. London metropolitan area, Paris region, industrialized Ruhr area, Po valley etc. There is critical issue of the emission inventories available for 10km resolution including the urban hot-spots, TNO emissions are adopted for this sensitivity study in 10km resolution for comparison of the results with the simulation based on merged TNO emissions, i.e. basically original EMEP emissions at 50 km grid. The sensitivity test to switch on/off Paris area emissions is analysed as well. Preliminary results for year 2005 are presented and discussed to reveal whether the concept of effective emission indices could help to parameterize the urban plume effects in lower resolution models. Interactive coupling is compared to study the potential of possible impact of urban air-pollution to the urban area climate.

Equilibrium Climate Sensitivity Obtained From Multimillennial Runs of Two GFDL Climate Models

NASA Astrophysics Data System (ADS)

Paynter, D.; Frölicher, T. L.; Horowitz, L. W.; Silvers, L. G.

2018-02-01

Equilibrium climate sensitivity (ECS), defined as the long-term change in global mean surface air temperature in response to doubling atmospheric CO2, is usually computed from short atmospheric simulations over a mixed layer ocean, or inferred using a linear regression over a short-time period of adjustment. We report the actual ECS from multimillenial simulations of two Geophysical Fluid Dynamics Laboratory (GFDL) general circulation models (GCMs), ESM2M, and CM3 of 3.3 K and 4.8 K, respectively. Both values are 1 K higher than estimates for the same models reported in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change obtained by regressing the Earth's energy imbalance against temperature. This underestimate is mainly due to changes in the climate feedback parameter (-α) within the first century after atmospheric CO2 has stabilized. For both GCMs it is possible to estimate ECS with linear regression to within 0.3 K by increasing CO2 at 1% per year to doubling and using years 51-350 after CO2 is constant. We show that changes in -α differ between the two GCMs and are strongly tied to the changes in both vertical velocity at 500 hPa (ω500) and estimated inversion strength that the GCMs experience during the progression toward the equilibrium. This suggests that while cloud physics parametrizations are important for determining the strength of -α, the substantially different atmospheric state resulting from a changed sea surface temperature pattern may be of equal importance.

Multi-scale enhancement of climate prediction over land by increasing the model sensitivity to vegetation variability in EC-Earth

NASA Astrophysics Data System (ADS)

Alessandri, Andrea; Catalano, Franco; De Felice, Matteo; Van Den Hurk, Bart; Doblas Reyes, Francisco; Boussetta, Souhail; Balsamo, Gianpaolo; Miller, Paul

2016-04-01

The EC-Earth earth system model has been recently developed to include the dynamics of vegetation. In its original formulation, vegetation variability is simply operated by the Leaf Area Index (LAI), which affects climate basically by changing the vegetation physiological resistance to evapotranspiration. This coupling has been found to have only a weak effect on the surface climate modeled by EC-Earth. In reality, the effective sub-grid vegetation fractional coverage will vary seasonally and at interannual time-scales in response to leaf-canopy growth, phenology and senescence. Therefore it affects biophysical parameters such as the albedo, surface roughness and soil field capacity. To adequately represent this effect in EC-Earth, we included an exponential dependence of the vegetation cover on the LAI. By comparing two sets of simulations performed with and without the new variable fractional-coverage parameterization, spanning retrospective predictions at the decadal (5-years), seasonal and sub-seasonal time-scales, we show for the first time a significant multi-scale enhancement of vegetation impacts in climate simulation and prediction over land. Particularly large effects at multiple time scales are shown over boreal winter middle-to-high latitudes over Canada, West US, Eastern Europe, Russia and eastern Siberia due to the implemented time-varying shadowing effect by tree-vegetation on snow surfaces. Over Northern Hemisphere boreal forest regions the improved representation of vegetation cover tends to correct the winter warm biases, improves the climate change sensitivity, the decadal potential predictability as well as the skill of forecasts at seasonal and sub-seasonal time-scales. Significant improvements of the prediction of 2m temperature and rainfall are also shown over transitional land surface hot spots. Both the potential predictability at decadal time-scale and seasonal-forecasts skill are enhanced over Sahel, North American Great Plains, Nordeste Brazil and South East Asia, mainly related to improved performance in the surface evapotranspiration.

Multi-scale enhancement of climate prediction over land by increasing the model sensitivity to vegetation variability in EC-Earth

NASA Astrophysics Data System (ADS)

Alessandri, Andrea; Catalano, Franco; De Felice, Matteo; Van Den Hurk, Bart; Doblas Reyes, Francisco; Boussetta, Souhail; Balsamo, Gianpaolo; Miller, Paul A.

2017-08-01

The EC-Earth earth system model has been recently developed to include the dynamics of vegetation. In its original formulation, vegetation variability is simply operated by the Leaf Area Index (LAI), which affects climate basically by changing the vegetation physiological resistance to evapotranspiration. This coupling has been found to have only a weak effect on the surface climate modeled by EC-Earth. In reality, the effective sub-grid vegetation fractional coverage will vary seasonally and at interannual time-scales in response to leaf-canopy growth, phenology and senescence. Therefore it affects biophysical parameters such as the albedo, surface roughness and soil field capacity. To adequately represent this effect in EC-Earth, we included an exponential dependence of the vegetation cover on the LAI. By comparing two sets of simulations performed with and without the new variable fractional-coverage parameterization, spanning from centennial (twentieth century) simulations and retrospective predictions to the decadal (5-years), seasonal and weather time-scales, we show for the first time a significant multi-scale enhancement of vegetation impacts in climate simulation and prediction over land. Particularly large effects at multiple time scales are shown over boreal winter middle-to-high latitudes over Canada, West US, Eastern Europe, Russia and eastern Siberia due to the implemented time-varying shadowing effect by tree-vegetation on snow surfaces. Over Northern Hemisphere boreal forest regions the improved representation of vegetation cover tends to correct the winter warm biases, improves the climate change sensitivity, the decadal potential predictability as well as the skill of forecasts at seasonal and weather time-scales. Significant improvements of the prediction of 2 m temperature and rainfall are also shown over transitional land surface hot spots. Both the potential predictability at decadal time-scale and seasonal-forecasts skill are enhanced over Sahel, North American Great Plains, Nordeste Brazil and South East Asia, mainly related to improved performance in the surface evapotranspiration.

Multi-scale enhancement of climate prediction over land by increasing the model sensitivity to vegetation variability in EC-Earth

NASA Astrophysics Data System (ADS)

Alessandri, Andrea; Catalano, Franco; De Felice, Matteo; Van Den Hurk, Bart; Doblas Reyes, Francisco; Boussetta, Souhail; Balsamo, Gianpaolo; Miller, Paul A.

2017-04-01

The EC-Earth earth system model has been recently developed to include the dynamics of vegetation. In its original formulation, vegetation variability is simply operated by the Leaf Area Index (LAI), which affects climate basically by changing the vegetation physiological resistance to evapotranspiration. This coupling has been found to have only a weak effect on the surface climate modeled by EC-Earth. In reality, the effective sub-grid vegetation fractional coverage will vary seasonally and at interannual time-scales in response to leaf-canopy growth, phenology and senescence. Therefore it affects biophysical parameters such as the albedo, surface roughness and soil field capacity. To adequately represent this effect in EC-Earth, we included an exponential dependence of the vegetation cover on the LAI. By comparing two sets of simulations performed with and without the new variable fractional-coverage parameterization, spanning from centennial (20th Century) simulations and retrospective predictions to the decadal (5-years), seasonal and weather time-scales, we show for the first time a significant multi-scale enhancement of vegetation impacts in climate simulation and prediction over land. Particularly large effects at multiple time scales are shown over boreal winter middle-to-high latitudes over Canada, West US, Eastern Europe, Russia and eastern Siberia due to the implemented time-varying shadowing effect by tree-vegetation on snow surfaces. Over Northern Hemisphere boreal forest regions the improved representation of vegetation cover tends to correct the winter warm biases, improves the climate change sensitivity, the decadal potential predictability as well as the skill of forecasts at seasonal and weather time-scales. Significant improvements of the prediction of 2m temperature and rainfall are also shown over transitional land surface hot spots. Both the potential predictability at decadal time-scale and seasonal-forecasts skill are enhanced over Sahel, North American Great Plains, Nordeste Brazil and South East Asia, mainly related to improved performance in the surface evapotranspiration.

Ocean Heat Uptake Slows 21st Century Surface Warming Driven by Extratropical Cloud Feedbacks

NASA Astrophysics Data System (ADS)

Frey, W.; Maroon, E.; Pendergrass, A. G.; Kay, J. E.

2017-12-01

Equilibrium climate sensitivity (ECS), the warming in response to instantaneously doubled CO2, has long been used to compare climate models. In many models, ECS is well correlated with warming produced by transient forcing experiments. Modifications to cloud phase at high latitudes in a state-of-the-art climate model, the Community Earth System Model (CESM), produce a large increase in ECS (1.5 K) via extratropical cloud feedbacks. However, only a small surface warming increase occurs in a realistic 21st century simulation including a full-depth dynamic ocean and the "business as usual" RCP8.5 emissions scenario. In fact, the increase in surface warming is only barely above the internal variability-generated range in the CESM Large Ensemble. The small change in 21st century warming is attributed to subpolar ocean heat uptake in both hemispheres. In the Southern Ocean, the mean-state circulation takes up heat while in the North Atlantic a slowdown in circulation acts as a feedback to slow surface warming. These results show the importance of subpolar ocean heat uptake in controlling the pace of warming and demonstrate that ECS cannot be used to reliably infer transient warming when it is driven by extratropical feedbacks.

Idealized climate change simulations with a high-resolution physical model: HadGEM3-GC2

NASA Astrophysics Data System (ADS)

Senior, Catherine A.; Andrews, Timothy; Burton, Chantelle; Chadwick, Robin; Copsey, Dan; Graham, Tim; Hyder, Pat; Jackson, Laura; McDonald, Ruth; Ridley, Jeff; Ringer, Mark; Tsushima, Yoko

2016-06-01

Idealized climate change simulations with a new physical climate model, HadGEM3-GC2 from The Met Office Hadley Centre are presented and contrasted with the earlier MOHC model, HadGEM2-ES. The role of atmospheric resolution is also investigated. The Transient Climate Response (TCR) is 1.9 K/2.1 K at N216/N96 and Effective Climate Sensitivity (ECS) is 3.1 K/3.2 K at N216/N96. These are substantially lower than HadGEM2-ES (TCR: 2.5 K; ECS: 4.6 K) arising from a combination of changes in the size of climate feedbacks. While the change in the net cloud feedback between HadGEM3 and HadGEM2 is relatively small, there is a change in sign of its longwave and a strengthening of its shortwave components. At a global scale, there is little impact of the increase in atmospheric resolution on the future climate change signal and even at a broad regional scale, many features are robust including tropical rainfall changes, however, there are some significant exceptions. For the North Atlantic and western Europe, the tripolar pattern of winter storm changes found in most CMIP5 models is little impacted by resolution but for the most intense storms, there is a larger percentage increase in number at higher resolution than at lower resolution. Arctic sea-ice sensitivity shows a larger dependence on resolution than on atmospheric physics.

An analytical approach to separate climate and human contributions to basin streamflow variability

NASA Astrophysics Data System (ADS)

Li, Changbin; Wang, Liuming; Wanrui, Wang; Qi, Jiaguo; Linshan, Yang; Zhang, Yuan; Lei, Wu; Cui, Xia; Wang, Peng

2018-04-01

Climate variability and anthropogenic regulations are two interwoven factors in the ecohydrologic system across large basins. Understanding the roles that these two factors play under various hydrologic conditions is of great significance for basin hydrology and sustainable water utilization. In this study, we present an analytical approach based on coupling water balance method and Budyko hypothesis to derive effectiveness coefficients (ECs) of climate change, as a way to disentangle contributions of it and human activities to the variability of river discharges under different hydro-transitional situations. The climate dominated streamflow change (ΔQc) by EC approach was compared with those deduced by the elasticity method and sensitivity index. The results suggest that the EC approach is valid and applicable for hydrologic study at large basin scale. Analyses of various scenarios revealed that contributions of climate change and human activities to river discharge variation differed among the regions of the study area. Over the past several decades, climate change dominated hydro-transitions from dry to wet, while human activities played key roles in the reduction of streamflow during wet to dry periods. Remarkable decline of discharge in upstream was mainly due to human interventions, although climate contributed more to runoff increasing during dry periods in the semi-arid downstream. Induced effectiveness on streamflow changes indicated a contribution ratio of 49% for climate and 51% for human activities at the basin scale from 1956 to 2015. The mathematic derivation based simple approach, together with the case example of temporal segmentation and spatial zoning, could help people understand variation of river discharge with more details at a large basin scale under the background of climate change and human regulations.

Snow Sublimation in Mountain Environments and Its Sensitivity to Forest Disturbance and Climate Warming

NASA Astrophysics Data System (ADS)

Sexstone, Graham A.; Clow, David W.; Fassnacht, Steven R.; Liston, Glen E.; Hiemstra, Christopher A.; Knowles, John F.; Penn, Colin A.

2018-02-01

Snow sublimation is an important component of the snow mass balance, but the spatial and temporal variability of this process is not well understood in mountain environments. This study combines a process-based snow model (SnowModel) with eddy covariance (EC) measurements to investigate (1) the spatio-temporal variability of simulated snow sublimation with respect to station observations, (2) the contribution of snow sublimation to the ablation of the snowpack, and (3) the sensitivity and response of snow sublimation to bark beetle-induced forest mortality and climate warming across the north-central Colorado Rocky Mountains. EC-based observations of snow sublimation compared well with simulated snow sublimation at stations dominated by surface and canopy sublimation, but blowing snow sublimation in alpine areas was not well captured by the EC instrumentation. Water balance calculations provided an important validation of simulated sublimation at the watershed scale. Simulated snow sublimation across the study area was equivalent to 28% of winter precipitation on average, and the highest relative snow sublimation fluxes occurred during the lowest snow years. Snow sublimation from forested areas accounted for the majority of sublimation fluxes, highlighting the importance of canopy and sub-canopy surface sublimation in this region. Simulations incorporating the effects of tree mortality due to bark-beetle disturbance resulted in a 4% reduction in snow sublimation from forested areas. Snow sublimation rates corresponding to climate warming simulations remained unchanged or slightly increased, but total sublimation losses decreased by up to 6% because of a reduction in snow covered area and duration.

High resolution climate projection of storm surge at the Venetian coast

NASA Astrophysics Data System (ADS)

Mel, R.; Sterl, A.; Lionello, P.

2013-04-01

Climate change impact on storm surge regime is of great importance for the safety and maintenance of Venice. In this study a future storm surge scenario is evaluated using new high resolution sea level pressure and wind data recently produced by EC-Earth, an Earth System Model based on the operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (ECMWF). The study considers an ensemble of six 5 yr long simulations of the rcp45 scenario at 0.25° resolution and compares the 2094-2098 to the 2004-2008 period. EC-Earth sea level pressure and surface wind fields are used as input for a shallow water hydrodynamic model (HYPSE) which computes sea level and barotropic currents in the Adriatic Sea. Results show that a high resolution climate model is needed for producing realistic values of storm surge statistics and confirm previous studies in that they show little sensitivity of storm surge levels to climate change. However, some climate change signals are detected, such as increased persistence of high pressure conditions, an increased frequency of windless hour, and a decreased number of moderate windstorms.

Do Southern Ocean Cloud Feedbacks Matter for 21st Century Warming?

NASA Astrophysics Data System (ADS)

Frey, W. R.; Maroon, E. A.; Pendergrass, A. G.; Kay, J. E.

2017-12-01

Cloud phase improvements in a state-of-the-art climate model produce a large 1.5 K increase in equilibrium climate sensitivity (ECS, the surface warming in response to instantaneously doubled CO2) via extratropical shortwave cloud feedbacks. Here we show that the same model improvements produce only a small surface warming increase in a realistic 21st century emissions scenario. The small 21st century warming increase is attributed to extratropical ocean heat uptake. Southern Ocean mean-state circulation takes up heat while a slowdown in North Atlantic circulation acts as a feedback to slow surface warming. Persistent heat uptake by extratropical oceans implies that extratropical cloud biases may not be as important to 21st century warming as biases in other regions. Observational constraints on cloud phase and shortwave radiation that produce a large ECS increase do not imply large changes in 21st century warming.

SST Patterns, Atmospheric Variability, and Inferred Sensitivities in the CMIP5 Model Archive

NASA Astrophysics Data System (ADS)

Marvel, K.; Pincus, R.; Schmidt, G. A.

2017-12-01

An emerging consensus suggests that global mean feedbacks to increasing temperature are not constant in time. If feedbacks become more positive in the future, the equilibrium climate sensitivity (ECS) inferred from recent observed global energy budget constraints is likely to be biased low. Time-varying feedbacks are largely tied to evolving sea-surface temperature patterns. In particular, recent anomalously cool conditions in the tropical Pacific may have triggered feedbacks that are not reproduced in equilibrium simulations where the tropical Pacific and Southern Ocean have had time to warm. Here, we use AMIP and CMIP5 historical simulations to explore the ECS that may be inferred over the recent historical period. We find that in all but one CMIP5 model, the feedbacks triggered by observed SST patterns are significantly less positive than those arising from historical simulations in which SST patterns are allowed to evolve unconstrained. However, there are substantial variations in feedbacks even when the SST pattern is held fixed, suggesting that atmospheric and land variability contribute to uncertainty in the estimates of ECS obtained from recent observations of the global energy budget.

Impact of Experience Corps(®) participation on school climate.

PubMed

Parisi, Jeanine M; Ramsey, Christine M; Carlson, Michelle C; Xue, Qian-Li; Huang, Jin; Romani, William A; McGill, Sylvia; Seeman, Teresa E; Tanner, Elizabeth K; Barron, Jeremy; Tan, Erwin J; Gruenewald, Tara L; Diibor, Ike; Fried, Linda P; Rebok, George W

2015-07-01

We examined the impact of the Experience Corps(®) (EC) program on school climate within Baltimore City public elementary schools. In this program, teams of older adult volunteers were placed in high intensity (>15 h per week), meaningful roles in public elementary schools, to improve the educational outcomes of children as well as the health and well-being of volunteers. During the first year of EC participation, school climate was perceived more favorably among staff and students in EC schools as compared to those in comparison schools. However, with a few notable exceptions, perceived school climate did not differ for staff or students in intervention and comparison schools during the second year of exposure to the EC program. These findings suggest that perceptions of school climate may be altered by introducing a new program into elementary schools; however, research examining how perceptions of school climate are impacted over a longer period is warranted.

Impact of Experience Corps® Participation on School Climate

PubMed Central

Parisi, Jeanine M.; Ramsey, Christine M.; Carlson, Michelle C.; Xue, Qian-Li; Huang, Jin; Romani, William A.; McGill, Sylvia; Seeman, Teresa E.; Tanner, Elizabeth K.; Barron, Jeremy; Tan, Erwin; Gruenewald, Tara L.; Diibor, Ike; Fried, Linda P.; Rebok, George W.

2015-01-01

We examined the impact of the Experience Corps® (EC) program on school climate within Baltimore City public elementary schools. In this program, teams of older adult volunteers were placed in high intensity (>15 hours per week), meaningful roles in public elementary schools, to improve the educational outcomes of children as well as the health and well-being of volunteers. During the first year of EC participation, school climate was perceived more favorably among staff and students in EC schools as compared to those in comparison schools. However, with a few notable exceptions, perceived school climate did not differ for staff or students in intervention and comparison schools during the second year of exposure to the EC program. These findings suggest that perceptions of school climate may be altered by introducing a new program into elementary schools; however, research examining how perceptions of school climate are impacted over a longer period is warranted. PMID:25708453

Global land-atmosphere coupling associated with cold climate processes

NASA Astrophysics Data System (ADS)

Dutra, Emanuel

This dissertation constitutes an assessment of the role of cold processes, associated with snow cover, in controlling the land-atmosphere coupling. The work was based on model simulations, including offline simulations with the land surface model HTESSEL, and coupled atmosphere simulations with the EC-EARTH climate model. A revised snow scheme was developed and tested in HTESSEL and EC-EARTH. The snow scheme is currently operational at the European Centre for Medium-Range Weather Forecasts integrated forecast system, and in the default configuration of EC-EARTH. The improved representation of the snowpack dynamics in HTESSEL resulted in improvements in the near surface temperature simulations of EC-EARTH. The new snow scheme development was complemented with the option of multi-layer version that showed its potential in modeling thick snowpacks. A key process was the snow thermal insulation that led to significant improvements of the surface water and energy balance components. Similar findings were observed when coupling the snow scheme to lake ice, where lake ice duration was significantly improved. An assessment on the snow cover sensitivity to horizontal resolution, parameterizations and atmospheric forcing within HTESSEL highlighted the role of the atmospheric forcing accuracy and snowpack parameterizations in detriment of horizontal resolution over flat regions. A set of experiments with and without free snow evolution was carried out with EC-EARTH to assess the impact of the interannual variability of snow cover on near surface and soil temperatures. It was found that snow cover interannual variability explained up to 60% of the total interannual variability of near surface temperature over snow covered regions. Although these findings are model dependent, the results showed consistency with previously published work. Furthermore, the detailed validation of the snow dynamics simulations in HTESSEL and EC-EARTH guarantees consistency of the results.

Exploring Emotional Climate in Preservice Science Teacher Education

ERIC Educational Resources Information Center

Bellocchi, Alberto; Ritchie, Stephen M.; Tobin, Kenneth; Sandhu, Maryam; Sandhu, Satwant

2013-01-01

Classroom emotional climates (ECs) are interrelated with students' engagement with university courses. Despite growing interest in emotions and EC research, little is known about the ways in which social interactions and different subject matter mediate ECs in preservice science teacher education classes. In this study we investigated the EC…

Quantifying structural and physiological controls on variation in canopy transpiration among planted pine and hardwood species in the southern Appalachians

Treesearch

Chelcy R. Ford; Robert M. Hubbard; James M. Vose

2010-01-01

Recent studies have shown that planted pine stands exhibit higher evapotranspiration (ET) and are more sensitive to climatic conditions compared with hardwood stands. Whether this is due to management and stand effects, biological effects or their interaction is poorly understood. We estimated growing season canopy- and sap flux-scaled leaf-level transpiration (Ec and...

Antiplasmodial potential and quantification of aloin and aloe-emodin in Aloe vera collected from different climatic regions of India.

PubMed

Kumar, Sandeep; Yadav, Manila; Yadav, Amita; Rohilla, Pooja; Yadav, Jaya Parkash

2017-07-17

In this study, Aloe vera samples were collected from different climatic regions of India. Quantitative HPTLC (high performance thin layer chromatography) analysis of important anthraquinones aloin and aloe-emodin and antiplasmodial activity of crude aqueous extracts was done to estimate the effects of these constituents on antiplasmodial potential of the plant. HPTLC system equipped with a sample applicator Linomat V with CAMAG sample syringe, twin rough plate development chamber (20 x 10 cm), TLC Scanner 3 and integration software WINCATS 1.4.8 was used for analysis of aloin and aloe-emodin amount. The antiplasmodial activity of plant extracts was assessed against a chloroquine (CQ) sensitive strain of P. falciparum (MRC-2). Minimum Inhibitory Concentration (MIC) of aqueous extracts of selected samples was determined according to the World Health Organization (WHO) recommended method that was based on assessing the inhibition of schizont maturation in a 96-well microtitre plate. EC (effective concentration) values of different samples were observed to predict antiplasmodial potential of the plant in terms of their climatic zones. A maximum quantity of aloin and aloe-emodin i.e. 0.45 and 0.27 mg/g respectively was observed from the 12 samples of Aloe vera. The inhibited parasite growth with EC 50 values ranging from 0.289 to 1056 μg/ml. The antiplasmodial EC 50 value of positive control Chloroquine was observed 0.034 μg/ml and EC 50 values showed by aloin and aloe-emodin was 67 μg/ml and 22 μg/ml respectively. A positive correlation was reported between aloin and aloe-emodin. Antiplasmodial activity was increased with increase in the concentration of aloin and aloe-emodin. The quantity of aloin and aloe-emodin was decreased with rise in temperature hence it was negatively correlated with temperature. The extracts of Aloe vera collected from colder climatic regions showed good antiplasmodial activity and also showed the presence of higher amount of aloin and aloe-emodin in comparison to collected from warmer climatic sites. Study showed significant correlation between quantities of both the anthraquinones used as marker compounds and EC 50 values of the different Aloe vera extracts. Although, both the anthraquinones showed less antiplasmodial potential in comparison to crude extracts of different Aloe vera samples. Diverse climatic factors affect the quantity of tested compounds and antiplasmodial potential of the plant in different Aloe vera samples.

DataStreme Earth's Climate System: Building a Climate Literate Society through Effective Partnerships

NASA Astrophysics Data System (ADS)

Brey, J. A.; Geer, I. W.; Weinbeck, R. S.; Mills, E. W.; Nugnes, K. A.; Stimach, A. E.

2015-12-01

Effective partnerships are key to increasing climate and overall environmental literacy. Financial support from NSF, NASA, and NOAA has allowed the American Meteorological Society (AMS) to offer DataStreme courses for almost 20 years. DataStreme Atmosphere, Ocean, and Earth's Climate System (ECS) are offered each fall and spring semester by Local Implementation Teams (LITs) across the country in coordination with AMS Education Program scientists and educators who develop instructional materials, provide logistical support to the LITs, and administer the project. A long-standing partnership with State University of New York's The College at Brockport gives teachers the opportunity to receive 3 tuition-free graduate credits upon successful completion of each DataStreme course and construction of a Plan of Action for educational peer-training. DataStreme ECS investigates the fundamental science of Earth's climate system, explores humans' impact on it, and identifies actions needed in response to climate change. The course provides participants with the knowledge to make informed climate decisions. In fact, according to a recent three-year study conducted by AMS, 98% of DataStreme ECS participants reported an increase in environmental literacy as a result of the course. DataStreme Atmosphere, Ocean, and ECS content has been improved because of AMS partnerships with NOAA and NASA. Specifically, hundreds of NASA and NOAA scientists and faculty from numerous institutions both domestic and abroad have contributed and reviewed DataStreme ECS content. Additional collaborations with Consortium for Ocean Leadership and the U.S. Ice Drilling Program greatly improved the course's paleoclimate content. Looking ahead, the Climate Resilience Toolkit from NOAA's Climate Program Office will further bolster the course this fall. These partnerships have resulted in a powerful, content-rich climate science course for K-12 teachers, building the foundation to a climate literate society.

The Influence of Effortful Control and Empathy on Perception of School Climate

ERIC Educational Resources Information Center

Zorza, Juan P.; Marino, Julián; Mesas, Alberto Acosta

2015-01-01

The purpose of this study was to determine the predictive power of effortful control (EC) and empathy for perception of school climate. Self-report measures of EC, dispositional empathy, and perception of school climate were obtained for 398 students (204 females) aged 12 to 13. Sociometric status was peer-evaluated, and academic achievement was…

Transpiration and stomatal conductance in a young secondary tropical montane forest: contrasts between native trees and invasive understorey shrubs.

PubMed

Ghimire, Chandra Prasad; Bruijnzeel, L Adrian; Lubczynski, Maciek W; Zwartendijk, Bob W; Odongo, Vincent Omondi; Ravelona, Maafaka; van Meerveld, H J Ilja

2018-04-21

It has been suggested that vigorous secondary tropical forests can have very high transpiration rates, but sap flow and stomatal conductance dynamics of trees and shrubs in these forests are understudied. In an effort to address this knowledge gap, sap flow (thermal dissipation method, 12 trees) and stomatal conductance (porometry, six trees) were measured for young (5-7 years) Psiadia altissima (DC.) Drake trees, a widely occurring species dominating young regrowth following abandonment of swidden agriculture in upland eastern Madagascar. In addition, stomatal conductance (gs) was determined for three individuals of two locally common invasive shrubs (Lantana camara L. and Rubus moluccanus L.) during three periods with contrasting soil moisture conditions. Values of gs for the three investigated species were significantly higher and more sensitive to climatic conditions during the wet period compared with the dry period. Further, gs of the understorey shrubs was much more sensitive to soil moisture content than that of the trees. Tree transpiration rates (Ec) were relatively stable during the dry season and were only affected somewhat by soil water content at the end of the dry season, suggesting the trees had continued access to soil water despite drying out of the topsoil. The Ec exhibited a plateau-shaped relation with vapour pressure deficit (VPD), which was attributed to stomatal closure at high VPD. Vapour pressure deficit was the major driver of variation in Ec, during both the wet and the dry season. Overall water use of the trees was modest, possibly reflecting low site fertility after three swidden cultivation cycles. The observed contrast in gs response to soil water and climatic conditions for the trees and shrubs underscores the need to take root distributions into account when modelling transpiration from regenerating tropical forests.

Exploring emotional climate in preservice science teacher education

NASA Astrophysics Data System (ADS)

Bellocchi, Alberto; Ritchie, Stephen M.; Tobin, Kenneth; Sandhu, Maryam; Sandhu, Satwant

2013-09-01

Classroom emotional climates (ECs) are interrelated with students' engagement with university courses. Despite growing interest in emotions and EC research, little is known about the ways in which social interactions and different subject matter mediate ECs in preservice science teacher education classes. In this study we investigated the EC and associated classroom interactions in a preservice science teacher education class. We were interested in the ways in which salient classroom interactions were related to the EC during lessons centered on debates about science-based issues (e.g., nuclear energy alternatives). Participants used audience response technology to indicate their perceptions of the EC. Analysis of conversation for salient video clips and analysis of non-verbal conduct (acoustic parameters, body movements, and facial expressions) supplemented EC data. One key contribution that this study makes to preservice science teacher education is to identify the micro-processes of successful and unsuccessful class interactions that were associated with positive and neutral EC. The structure of these interactions can inform the practice of other science educators who wish to produce positive ECs in their classes. The study also extends and explicates the construct of intensity of EC.

Snow sublimation in mountain environments and its sensitivity to forest disturbance and climate warming

USGS Publications Warehouse

Sexstone, Graham A.; Clow, David W.; Fassnacht, Steven R.; Liston, Glen E.; Hiemstra, Christopher A.; Knowles, John F.; Penn, Colin A.

2018-01-01

Snow sublimation is an important component of the snow mass balance, but the spatial and temporal variability of this process is not well understood in mountain environments. This study combines a process‐based snow model (SnowModel) with eddy covariance (EC) measurements to investigate (1) the spatio‐temporal variability of simulated snow sublimation with respect to station observations, (2) the contribution of snow sublimation to the ablation of the snowpack, and (3) the sensitivity and response of snow sublimation to bark beetle‐induced forest mortality and climate warming across the north‐central Colorado Rocky Mountains. EC‐based observations of snow sublimation compared well with simulated snow sublimation at stations dominated by surface and canopy sublimation, but blowing snow sublimation in alpine areas was not well captured by the EC instrumentation. Water balance calculations provided an important validation of simulated sublimation at the watershed scale. Simulated snow sublimation across the study area was equivalent to 28% of winter precipitation on average, and the highest relative snow sublimation fluxes occurred during the lowest snow years. Snow sublimation from forested areas accounted for the majority of sublimation fluxes, highlighting the importance of canopy and sub‐canopy surface sublimation in this region. Simulations incorporating the effects of tree mortality due to bark‐beetle disturbance resulted in a 4% reduction in snow sublimation from forested areas. Snow sublimation rates corresponding to climate warming simulations remained unchanged or slightly increased, but total sublimation losses decreased by up to 6% because of a reduction in snow covered area and duration.

CO2 and CH4 exchange by Phragmites australis under different climates

NASA Astrophysics Data System (ADS)

Serrano Ortiz, Penélope; Chojnickic, Bogdan H.; Sánchez-Cañete, Enrique P.; Kowalska, Natalia; López-Ballesteros, Ana; Fernández, Néstor; Urbaniak, Marek; Olejnik, Janusz; Kowalski, Andrew S.

2015-04-01

The key role of wetlands regarding global warming is the resulting balance between net CO2 assimilation, via photosynthesis, and CO2 and CH4 emissions, given the potential to release stored carbon, because of the high temperature sensitivity of heterotrophic soil respiration and anoxic conditions. However, it is still unknown whether wetlands will convert from long-term carbon sinks to sources as a result of climate change and other anthropogenic effects such as land use changes. Phragmites australis is one of the most common species found in wetlands and is considered the most globally widespread and productive plant species in this type of ecosystem. In this context, the main objective of this study is to analyse the GHG exchange (CO2 and CH4) of two wetlands with Phragmites australis as the dominant species under different climates using the eddy covariance (EC) technique. The first site, Padul, is located in southern Spain, with a sub-humid warm climate, characterised by a mean annual temperature of 16°C and annual precipitation of ca. 470 mm, with a very dry summer. The second site, Rzecin is located in Poland with a mean annual temperature of 8°C, and annual precipitation around 600mm with no dry season. The Padul EC station is equipped with two infrared gas analysers to measure CO2 and CH4 fluxes (LI-7200 and LI-7700 respectively) while the Rzecin EC station has the same CH4 sensor as Padul, but also a sensor measuring both GHG fluxes (DLT-100 Fast Methane Analyser, Los Gatos). In this study, we present: i) the results of a CH4 analyser inter-comparison campaign (LI-7700 vs. Los Gatos), ii) a comparative analysis of the functional behaviour of respiration and photosynthesis in both sites testing relationships between CO2 fluxes measured with the EC technique and meteorological variables such as temperature and direct or diffuse radiation and iii) the CH4 dynamicsat both sites by identifying, when possible, annual, seasonal and diurnal patterns.

Modelling the Climate - Greenland Ice Sheet Interaction in the Coupled Ice-sheet/Climate Model EC-EARTH - PISM

NASA Astrophysics Data System (ADS)

Yang, S.; Madsen, M. S.; Rodehacke, C. B.; Svendsen, S. H.; Adalgeirsdottir, G.

2014-12-01

Recent observations show that the Greenland ice sheet (GrIS) has been losing mass with an increasing speed during the past decades. Predicting the GrIS changes and their climate consequences relies on the understanding of the interaction of the GrIS with the climate system on both global and local scales, and requires climate model systems with an explicit and physically consistent ice sheet module. A fully coupled global climate model with a dynamical ice sheet model for the GrIS has recently been developed. The model system, EC-EARTH - PISM, consists of the EC-EARTH, an atmosphere, ocean and sea ice model system, and the Parallel Ice Sheet Model (PISM). The coupling of PISM includes a modified surface physical parameterization in EC-EARTH adapted to the land ice surface over glaciated regions in Greenland. The PISM ice sheet model is forced with the surface mass balance (SMB) directly computed inside the EC-EARTH atmospheric module and accounting for the precipitation, the surface evaporation, and the melting of snow and ice over land ice. PISM returns the simulated basal melt, ice discharge and ice cover (extent and thickness) as boundary conditions to EC-EARTH. This coupled system is mass and energy conserving without being constrained by any anomaly correction or flux adjustment, and hence is suitable for investigation of ice sheet - climate feedbacks. Three multi-century experiments for warm climate scenarios under (1) the RCP85 climate forcing, (2) an abrupt 4xCO2 and (3) an idealized 1% per year CO2 increase are performed using the coupled model system. The experiments are compared with their counterparts of the standard CMIP5 simulations (without the interactive ice sheet) to evaluate the performance of the coupled system and to quantify the GrIS feedbacks. In particular, the evolution of the Greenland ice sheet under the warm climate and its impacts on the climate system are investigated. Freshwater fluxes from the Greenland ice sheet melt to the Arctic and North Atlantic basin and their influence on the ocean stratification and ocean circulation are analysed. The changes in the surface climate and the atmospheric circulation associated with the impact of the Greenland ice sheet changes are quantified. The interaction between the Greenland ice sheet and Arctic sea ice is also examined.

Net carbon balance of three full crop rotations at an agricultural site near Gebesee, Germany

NASA Astrophysics Data System (ADS)

Hurkuck, M.; Brümmer, C.; Kolle, O.; Kutsch, W. L.; Moffat, A. M.; Mukwashi, K.; Truckenbrodt, S. C.; Herbst, M.

2015-12-01

Continuous eddy-covariance (EC) measurements of biosphere-atmosphere CO2 and H2O exchange have been conducted since 2001 at an agricultural site near Gebesee, Germany, thus providing one of the longest EC time series of European croplands. During the experimental period, winter wheat and winter barley were alternately planted with potatoes, sugar beet, rape, and peppermint covering three full crop rotations (2001-2004, 2005-2009, and 2010-2014). In this study, data of 14 years of net ecosystem CO2 exchange (NEE) and evapotranspiration (E) were re-calculated. Based on these data, we present the net carbon (C) balance (net biome production, NBP) accounting for any additional C input by fertilization and C output by harvest. Further emphasis was placed on the sensitivity of water use efficiency (WUE) and E to climate and crop type. The main aim was to investigate the interannual variability in both NBP and WUE, thus disentangling the impacts of climatic conditions and land management on the net C balance as well as on WUE and E.

We teach as we are taught: exploring the potential for emotional climate to enhance elementary science preservice teacher education

NASA Astrophysics Data System (ADS)

Olitsky, Stacy

2013-09-01

Bellocchi, Ritchie, Tobin, Sandhu and Sandhu's (2013) study highlights the crucial role that emotions play in learning at the university level in a preservice secondary science teacher education class. They examine the classroom structures that tended to lead to both a positive valence and a high level of intensity of the emotional climate (EC). This article explores the implications of their study for better understanding how to foster a positive classroom emotional climate for elementary level preservice teachers, given the specifics of elementary school environments. Drawing on theories of interactional solidarity. I explore the implications of EC for increasing pre-service teachers' capacity to avoid order-giving rituals and to create science-centered communities in their classrooms. I also suggest possible areas for future research, such as the role of expectations in EC, the different EC outcomes of lectures, EC and the development of confidence in science, and the ways in which teacher candidates are positioned within interaction rituals in elementary science methods classes.

Adaptive fine root foraging patterns in climate experiments and natural gradients

NASA Astrophysics Data System (ADS)

Ostonen, Ivika; Truu, Marika; Parts, Kaarin; Truu, Jaak

2017-04-01

Site based manipulative experiments and studies along climatic gradients have long been keystones of ecological research. We aimed to compare the response of ectomycorrhizal (EcM) and fine roots in manipulative studies and along climate gradient to describe the universal trends in root traits and to raise hypotheses about general mechanisms in fine root system adaptation of forest trees in global change. The root traits from two climate manipulation experiments - Bangor FACE and FAHM in Estonia, manipulated by CO2 concentration and relative air humidity in silver birch forest ecosystems, respectively and the data for three most ubiquitous tree species - Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and silver birch (Betula pendula) stands along natural gradient encompassing different climate and forest zones in Northern Europe were analysed. There are two main strategies in response of fine root system of trees: A) an extensive increase in absorptive root biomass, surface area and length, or B) a greater reliance on root-associated EcM fungi and bacterial communities with a smaller investment to absorptive root biomass. Trees in all studies tended to increase the EcM root biomass and the proportion of EcM root biomass of total fine root biomass towards harsh (northern boreal forests) or changed conditions (stress created by the increase in CO2 concentration or relative air humidity). We envisage a role of trilateral relation between the morphological traits of absorptive fine roots, exploration types of colonising EcM fungi and rhizosphere and bulk soil bacterial community structure. A significant change in EcM absorptive fine root biomass in all experiments and for all studied tree species coincided with changes in absorptive root morphology, being longer and thinner root tips with higher root tissue density in poor/treated sites. These changes were associated with significant shifts in community structure of dominating EcM fungi as well as soil and rhizosphere bacterial communities. We suggest a multidimensional concept of absorptive fine root foraging strategies involving both qualitative and quantitative changes in root-mycorhizosphere along environmental gradients and in climate experiments.

Climate risk index for Italy.

PubMed

Mysiak, Jaroslav; Torresan, Silvia; Bosello, Francesco; Mistry, Malcolm; Amadio, Mattia; Marzi, Sepehr; Furlan, Elisa; Sperotto, Anna

2018-06-13

We describe a climate risk index that has been developed to inform national climate adaptation planning in Italy and that is further elaborated in this paper. The index supports national authorities in designing adaptation policies and plans, guides the initial problem formulation phase, and identifies administrative areas with higher propensity to being adversely affected by climate change. The index combines (i) climate change-amplified hazards; (ii) high-resolution indicators of exposure of chosen economic, social, natural and built- or manufactured capital (MC) assets and (iii) vulnerability, which comprises both present sensitivity to climate-induced hazards and adaptive capacity. We use standardized anomalies of selected extreme climate indices derived from high-resolution regional climate model simulations of the EURO-CORDEX initiative as proxies of climate change-altered weather and climate-related hazards. The exposure and sensitivity assessment is based on indicators of manufactured, natural, social and economic capital assets exposed to and adversely affected by climate-related hazards. The MC refers to material goods or fixed assets which support the production process (e.g. industrial machines and buildings); Natural Capital comprises natural resources and processes (renewable and non-renewable) producing goods and services for well-being; Social Capital (SC) addressed factors at the individual (people's health, knowledge, skills) and collective (institutional) level (e.g. families, communities, organizations and schools); and Economic Capital (EC) includes owned and traded goods and services. The results of the climate risk analysis are used to rank the subnational administrative and statistical units according to the climate risk challenges, and possibly for financial resource allocation for climate adaptation.This article is part of the theme issue 'Advances in risk assessment for climate change adaptation policy'. © 2018 The Authors.

Climate risk index for Italy

NASA Astrophysics Data System (ADS)

Mysiak, Jaroslav; Torresan, Silvia; Bosello, Francesco; Mistry, Malcolm; Amadio, Mattia; Marzi, Sepehr; Furlan, Elisa; Sperotto, Anna

2018-06-01

We describe a climate risk index that has been developed to inform national climate adaptation planning in Italy and that is further elaborated in this paper. The index supports national authorities in designing adaptation policies and plans, guides the initial problem formulation phase, and identifies administrative areas with higher propensity to being adversely affected by climate change. The index combines (i) climate change-amplified hazards; (ii) high-resolution indicators of exposure of chosen economic, social, natural and built- or manufactured capital (MC) assets and (iii) vulnerability, which comprises both present sensitivity to climate-induced hazards and adaptive capacity. We use standardized anomalies of selected extreme climate indices derived from high-resolution regional climate model simulations of the EURO-CORDEX initiative as proxies of climate change-altered weather and climate-related hazards. The exposure and sensitivity assessment is based on indicators of manufactured, natural, social and economic capital assets exposed to and adversely affected by climate-related hazards. The MC refers to material goods or fixed assets which support the production process (e.g. industrial machines and buildings); Natural Capital comprises natural resources and processes (renewable and non-renewable) producing goods and services for well-being; Social Capital (SC) addressed factors at the individual (people's health, knowledge, skills) and collective (institutional) level (e.g. families, communities, organizations and schools); and Economic Capital (EC) includes owned and traded goods and services. The results of the climate risk analysis are used to rank the subnational administrative and statistical units according to the climate risk challenges, and possibly for financial resource allocation for climate adaptation. This article is part of the theme issue `Advances in risk assessment for climate change adaptation policy'.

Climate risk index for Italy

PubMed Central

Torresan, Silvia; Bosello, Francesco; Mistry, Malcolm; Amadio, Mattia; Marzi, Sepehr; Furlan, Elisa; Sperotto, Anna

2018-01-01

We describe a climate risk index that has been developed to inform national climate adaptation planning in Italy and that is further elaborated in this paper. The index supports national authorities in designing adaptation policies and plans, guides the initial problem formulation phase, and identifies administrative areas with higher propensity to being adversely affected by climate change. The index combines (i) climate change-amplified hazards; (ii) high-resolution indicators of exposure of chosen economic, social, natural and built- or manufactured capital (MC) assets and (iii) vulnerability, which comprises both present sensitivity to climate-induced hazards and adaptive capacity. We use standardized anomalies of selected extreme climate indices derived from high-resolution regional climate model simulations of the EURO-CORDEX initiative as proxies of climate change-altered weather and climate-related hazards. The exposure and sensitivity assessment is based on indicators of manufactured, natural, social and economic capital assets exposed to and adversely affected by climate-related hazards. The MC refers to material goods or fixed assets which support the production process (e.g. industrial machines and buildings); Natural Capital comprises natural resources and processes (renewable and non-renewable) producing goods and services for well-being; Social Capital (SC) addressed factors at the individual (people's health, knowledge, skills) and collective (institutional) level (e.g. families, communities, organizations and schools); and Economic Capital (EC) includes owned and traded goods and services. The results of the climate risk analysis are used to rank the subnational administrative and statistical units according to the climate risk challenges, and possibly for financial resource allocation for climate adaptation. This article is part of the theme issue ‘Advances in risk assessment for climate change adaptation policy’. PMID:29712797

Intra-Urban Variability in Elemental Carbon Deposition to Tree Canopies

NASA Astrophysics Data System (ADS)

Barrett, T. E.; Ponette-González, A.; Rindy, J. E.; Sheesley, R. J.

2017-12-01

Urban areas cover <1% of the earth's land surface, yet they represent globally significant sources of atmospheric elemental carbon (EC). A product of incomplete fossil fuel, biofuel, and biomass combustion, EC is a powerful climate-forcing agent and a significant component of fine particulate matter in urban atmospheres. Thus, understanding the factors that govern EC removal in urban areas could help mitigate climate change, while improving air quality for urban residents. EC particles can be removed from the atmosphere in precipitation (wet and fog deposition) or they can settle directly onto receptor surfaces (dry deposition). Only limited measurements indicate that EC deposition is higher in urban than in rural and remote regions. However, EC deposition likely exhibits considerable intra-urban variability, with tree canopies serving as potentially important sinks for EC on the cityscape. The goal of this research is to quantify spatial variability in total (wet + dry) EC deposition to urban tree canopies in the Dallas-Fort Worth Metroplex. Using a stratified non-random sampling design, 41 oak trees (22 post oak (Quercus stellata) and 19 live oak (Quercus virginiana)) were selected near (<100 m) and far from roads (>100 m) for measurements of throughfall (water that falls from the canopy to the forest floor). Additionally, 16 bulk rainfall samplers were deployed in grassy areas with no canopy cover. Results from one rain event indicate a volume weighted mean concentration of 83 µg EC L-1 in post oak throughfall, 36 µg EC L-1 in live oak throughfall, and 4 µg EC L-1 in bulk rainfall. Total EC deposition to oak tree canopies was 2.0 ± 2.1 (SD) mg m-2 for post oak and 0.7 ± 0.3 mg m-2 for live oak. Bulk rainfall deposition was 0.08 ± 0.1 mg m-2. Our preliminary findings show that trees are effective urban air filters, removing 9-25 times more EC from the atmosphere than rainwater alone. Resolving surface controls on atmospheric EC removal is key to developing and assessing near-term climate and air quality mitigation strategies.

An Empirical Approach to Predicting Effects of Climate Change on Stream Water Chemistry

NASA Astrophysics Data System (ADS)

Olson, J. R.; Hawkins, C. P.

2014-12-01

Climate change may affect stream solute concentrations by three mechanisms: dilution associated with increased precipitation, evaporative concentration associated with increased temperature, and changes in solute inputs associated with changes in climate-driven weathering. We developed empirical models predicting base-flow water chemistry from watershed geology, soils, and climate for 1975 individual stream sites across the conterminous USA. We then predicted future solute concentrations (2065 and 2099) by applying down-scaled global climate model predictions to these models. The electrical conductivity model (EC, model R2 = 0.78) predicted mean increases in EC of 19 μS/cm by 2065 and 40 μS/cm by 2099. However predicted responses for individual streams ranged from a 43% decrease to a 4x increase. Streams with the greatest predicted decreases occurred in the southern Rocky Mountains and Mid-West, whereas southern California and Sierra Nevada streams showed the greatest increases. Generally, streams in dry areas underlain by non-calcareous rocks were predicted to be the most vulnerable to increases in EC associated with climate change. Predicted changes in other water chemistry parameters (e.g., Acid Neutralization Capacity (ANC), SO4, and Ca) were similar to EC, although the magnitude of ANC and SO4 change was greater. Predicted changes in ANC and SO4 are in general agreement with those changes already observed in seven locations with long term records.

Comparing the sensitivity of chlorophytes, cyanobacteria, and diatoms to major-use antibiotics.

PubMed

Guo, Jiahua; Selby, Katherine; Boxall, Alistair B A

2016-10-01

The occurrence of antibiotic residues in the aquatic environment is an emerging concern. In contrast to daphnia and fish, algae are known to be particularly sensitive to antibiotic exposure. However, to date, a systematic evaluation of the sensitivity of different algal species to antibiotics has not been performed. The aim of the present study was therefore to explore the sensitivity of a battery of algal species toward antibiotic exposures. The present study investigated the growth inhibition effects of 3 major-use antibiotics, tylosin, lincomycin, and trimethoprim, on 7 algal species from the chlorophyte, cyanobacteria, and diatom groups. Based on median effective concentration (EC50) values, cyanobacteria (EC50 = 0.095-0.13 μmol/L) were found to be the most sensitive group to lincomycin followed by chlorophytes (EC50 = 7.36-225.73 μmol/L) and diatoms (EC50 > 225.73 μmol/L). Cyanobacteria were also the most sensitive group to tylosin (EC50 = 0.09-0.092 μmol/L), but, for this compound, diatoms (EC50 = 1.33-5.7 μmol/L) were more sensitive than chlorophytes (EC50 = 4.14-81.2 μmol/L). Diatoms were most sensitive to trimethoprim (EC50 = 7.36-74.61 μmol/L), followed by cyanobacteria (EC50 = 315.78-344.45 μmol/L), and chlorophytes (EC50 > 344.45 μmol/L) for trimethoprim. Although these results partly support the current approach to regulatory environmental risk assessment (whereby cyanobacterial species are recommended for use with antibiotic compounds), they indicate that for some antibiotics this group might not be the most appropriate test organism. It is therefore suggested that environmental risk assessments consider data on 3 algal groups (chlorophytes, cyanobacteria, and diatoms) and use test species from these groups, which are consistently found to be the most sensitive (Pseudokirchneriella subcapitata, Anabaena flos-aquae, and Navicula pelliculosa). Environ Toxicol Chem 2016;35:2587-2596. © 2016 SETAC. © 2016 SETAC.

Evaluating the effects of climate change on summertime ozone using a relative response factor approach for policymakers.

PubMed

Avise, Jeremy; Abraham, Rodrigo Gonzalez; Chung, Serena H; Chen, Jack; Lamb, Brian; Salathé, Eric P; Zhang, Yongxin; Nolte, Christopher G; Loughlin, Daniel H; Guenther, Alex; Wiedinmyer, Christine; Duhl, Tiffany

2012-09-01

The impact of climate change on surface-level ozone is examined through a multiscale modeling effort that linked global and regional climate models to drive air quality model simulations. Results are quantified in terms of the relative response factor (RRF(E)), which estimates the relative change in peak ozone concentration for a given change in pollutant emissions (the subscript E is added to RRF to remind the reader that the RRF is due to emission changes only). A matrix of model simulations was conducted to examine the individual and combined effects offuture anthropogenic emissions, biogenic emissions, and climate on the RRF(E). For each member in the matrix of simulations the warmest and coolest summers were modeled for the present-day (1995-2004) and future (2045-2054) decades. A climate adjustment factor (CAF(C) or CAF(CB) when biogenic emissions are allowed to change with the future climate) was defined as the ratio of the average daily maximum 8-hr ozone simulated under a future climate to that simulated under the present-day climate, and a climate-adjusted RRF(EC) was calculated (RRF(EC) = RRF(E) x CAF(C)). In general, RRF(EC) > RRF(E), which suggests additional emission controls will be required to achieve the same reduction in ozone that would have been achieved in the absence of climate change. Changes in biogenic emissions generally have a smaller impact on the RRF(E) than does future climate change itself The direction of the biogenic effect appears closely linked to organic-nitrate chemistry and whether ozone formation is limited by volatile organic compounds (VOC) or oxides of nitrogen (NO(x) = NO + NO2). Regions that are generally NO(x) limited show a decrease in ozone and RRF(EC), while VOC-limited regions show an increase in ozone and RRF(EC). Comparing results to a previous study using different climate assumptions and models showed large variability in the CAF(CB). We present a methodology for adjusting the RRF to account for the influence of climate change on ozone. The findings of this work suggest that in some geographic regions, climate change has the potential to negate decreases in surface ozone concentrations that would otherwise be achieved through ozone mitigation strategies. In regions of high biogenic VOC emissions relative to anthropogenic NO(x) emissions, the impact of climate change is somewhat reduced, while the opposite is true in regions of high anthropogenic NO(x) emissions relative to biogenic VOC emissions. Further, different future climate realizations are shown to impact ozone in different ways.

Climate SPHINX: evaluating the impact of resolution and stochastic physics parameterisations in the EC-Earth global climate model

NASA Astrophysics Data System (ADS)

Davini, Paolo; von Hardenberg, Jost; Corti, Susanna; Christensen, Hannah M.; Juricke, Stephan; Subramanian, Aneesh; Watson, Peter A. G.; Weisheimer, Antje; Palmer, Tim N.

2017-03-01

The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity of present and future climate to model resolution and stochastic parameterisation. The EC-Earth Earth system model is used to explore the impact of stochastic physics in a large ensemble of 30-year climate integrations at five different atmospheric horizontal resolutions (from 125 up to 16 km). The project includes more than 120 simulations in both a historical scenario (1979-2008) and a climate change projection (2039-2068), together with coupled transient runs (1850-2100). A total of 20.4 million core hours have been used, made available from a single year grant from PRACE (the Partnership for Advanced Computing in Europe), and close to 1.5 PB of output data have been produced on SuperMUC IBM Petascale System at the Leibniz Supercomputing Centre (LRZ) in Garching, Germany. About 140 TB of post-processed data are stored on the CINECA supercomputing centre archives and are freely accessible to the community thanks to an EUDAT data pilot project. This paper presents the technical and scientific set-up of the experiments, including the details on the forcing used for the simulations performed, defining the SPHINX v1.0 protocol. In addition, an overview of preliminary results is given. An improvement in the simulation of Euro-Atlantic atmospheric blocking following resolution increase is observed. It is also shown that including stochastic parameterisation in the low-resolution runs helps to improve some aspects of the tropical climate - specifically the Madden-Julian Oscillation and the tropical rainfall variability. These findings show the importance of representing the impact of small-scale processes on the large-scale climate variability either explicitly (with high-resolution simulations) or stochastically (in low-resolution simulations).

Net ecosystem exchange of CO2 and H2O fluxes from irrigated grain sorghum and maize in the Texas High Plains.

PubMed

Wagle, Pradeep; Gowda, Prasanna H; Moorhead, Jerry E; Marek, Gary W; Brauer, David K

2018-05-08

Net ecosystem exchange (NEE) of carbon dioxide (CO 2 ) and water vapor (H 2 O) fluxes from irrigated grain sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.) fields in the Texas High Plains were quantified using the eddy covariance (EC) technique during 2014-2016 growing seasons and examined in terms of relevant controlling climatic variables. Eddy covariance measured evapotranspiration (ET EC ) was also compared against lysimeter measured ET (ET Lys ). Daily peak (7-day averages) NEE reached approximately -12 g C m -2 for sorghum and -14.78 g C m -2 for maize. Daily peak (7-day averages) ET EC reached approximately 6.5 mm for sorghum and 7.3 mm for maize. Higher leaf area index (5.7 vs 4-4.5 m 2  m -2 ) and grain yield (14 vs 8-9 t ha -1 ) of maize compared to sorghum caused larger magnitudes of NEE and ET EC in maize. Comparisons of ET EC and ET Lys showed a strong agreement (R 2  = 0.93-0.96), while the EC system underestimated ET by 15-24% as compared to lysimeter without any corrections or energy balance adjustments. Both NEE and ET EC were not inhibited by climatic variables during peak photosynthetic period even though diurnal peak values (~2-weeks average) of photosynthetic photon flux density (PPFD), air temperature (T a ), and vapor pressure deficit (VPD) had reached over 2000 μmol m -2  s -1 , 30 °C, and 2.5 kPa, respectively, indicating well adaptation of both C 4 crops in the Texas High Plains under irrigation. However, more sensitivity of NEE and H 2 O fluxes beyond threshold T a and VPD for maize than for sorghum indicated higher adaptability of sorghum for the region. These findings provide baseline information on CO 2 fluxes and ET for a minimally studied grain sorghum and offer a robust geographic comparison for maize outside the United States Corn Belt. However, longer-term measurements are required for assessing carbon and water dynamics of these globally important agro-ecosystems. Copyright © 2018. Published by Elsevier B.V.

Autumn temperature and carbon balance of a boreal Scots pine forest in Southern Finland

NASA Astrophysics Data System (ADS)

Vesala, T.; Launiainen, S.; Kolari, P.; Pumpanen, J.; Sevanto, S.; Hari, P.; Nikinmaa, E.; Kaski, P.; Mannila, H.; Ukkonen, E.; Piao, S. L.; Ciais, P.

2010-01-01

We analyzed the dynamics of carbon balance components: gross primary production (GPP) and total ecosystem respiration (TER), of a boreal Scots pine forest in Southern Finland. The main focus is on investigations of environmental drivers of GPP and TER and how they affect the inter-annual variation in the carbon balance in autumn (September-December). We used standard climate data and CO2 exchange measurements collected by the eddy covariance (EC) technique over 11 years. EC data revealed that increasing autumn temperature significantly enhances TER: the temperature sensitivity was 9.5 gC m-2 °C-1 for the period September-October (early autumn when high radiation levels still occur) and 3.8 gC m-2 °C-1 for November-December (late autumn with suppressed radiation level). The cumulative GPP was practically independent of the temperature in early autumn. In late autumn, air temperature could explain part of the variation in GPP but the temperature sensitivity was very weak, less than 1 gC m-2 °C-1. Two models, a stand photosynthesis model (COCA) and a global vegetation model (ORCHIDEE), were used for estimating stand GPP and its sensitivity to the temperature. The ORCHIDEE model was tested against the observations of GPP derived from EC data. The stand photosynthesis model COCA predicted that under a predescribed 3-6 °C temperature increase, the temperature sensitivity of 4-5 gC m-2 °C-1 in GPP may appear in early autumn. The analysis by the ORCHIDEE model revealed the model sensitivity to the temporal treatment of meteorological forcing. The model predictions were similar to observed ones when the site level 1/2-hourly time step was applied, but the results calculated by using daily meteorological forcing, interpolated to 1/2-hourly time step, were biased. This is due to the nonlinear relationship between the processes and the environmental factors.

High-accuracy and high-sensitivity spectroscopic measurement of dinitrogen pentoxide (N2O5) in an atmospheric simulation chamber using a quantum cascade laser.

PubMed

Yi, Hongming; Wu, Tao; Lauraguais, Amélie; Semenov, Vladimir; Coeur, Cecile; Cassez, Andy; Fertein, Eric; Gao, Xiaoming; Chen, Weidong

2017-12-04

A spectroscopic instrument based on a mid-infrared external cavity quantum cascade laser (EC-QCL) was developed for high-accuracy measurements of dinitrogen pentoxide (N 2 O 5 ) at the ppbv-level. A specific concentration retrieval algorithm was developed to remove, from the broadband absorption spectrum of N 2 O 5 , both etalon fringes resulting from the EC-QCL intrinsic structure and spectral interference lines of H 2 O vapour absorption, which led to a significant improvement in measurement accuracy and detection sensitivity (by a factor of 10), compared to using a traditional algorithm for gas concentration retrieval. The developed EC-QCL-based N 2 O 5 sensing platform was evaluated by real-time tracking N 2 O 5 concentration in its most important nocturnal tropospheric chemical reaction of NO 3 + NO 2 ↔ N 2 O 5 in an atmospheric simulation chamber. Based on an optical absorption path-length of L eff = 70 m, a minimum detection limit of 15 ppbv was achieved with a 25 s integration time and it was down to 3 ppbv in 400 s. The equilibrium rate constant K eq involved in the above chemical reaction was determined with direct concentration measurements using the developed EC-QCL sensing platform, which was in good agreement with the theoretical value deduced from a referenced empirical formula under well controlled experimental conditions. The present work demonstrates the potential and the unique advantage of the use of a modern external cavity quantum cascade laser for applications in direct quantitative measurement of broadband absorption of key molecular species involved in chemical kinetic and climate-change related tropospheric chemistry.

Aldosterone sensitizes connecting tubule glomerular feedback via the aldosterone receptor GPR30

PubMed Central

Ren, YiLin; D'Ambrosio, Martin A.; Garvin, Jeffrey L.; Leung, Pablo; Kutskill, Kristopher; Wang, Hong; Peterson, Edward L.

2014-01-01

Increasing Na delivery to epithelial Na channels (ENaC) in the connecting tubule (CNT) dilates the afferent arteriole (Af-Art), a process we call connecting tubule glomerular feedback (CTGF). We hypothesize that aldosterone sensitizes CTGF via a nongenomic mechanism that stimulates CNT ENaC via the aldosterone receptor GPR30. Rabbit Af-Arts and their adherent CNTs were microdissected and simultaneously perfused. Two consecutive CTGF curves were elicited by increasing luminal NaCl in the CNT. During the control period, the concentration of NaCl that elicited a half-maximal response (EC50) was 37.0 ± 2.0 mmol/l; addition of aldosterone 10−8 mol/l to the CNT lumen caused a left-shift (decrease) in EC50 to 19.3 ± 1.3 mmol/l (P = 0.001 vs. control; n = 6). Neither the transcription inhibitor actinomycin D nor the translation inhibitor cycloheximide prevented the effect of aldosterone (control EC50 = 34.7 ± 1.9 mmol/l; aldosterone+actinomycin D EC50 = 22.6 ± 1.6 mmol/l; P < 0.001 and control EC50 = 32.4 ± 4.3 mmol/l; aldosterone+cycloheximide EC50 = 17.4 ± 3.3 mmol/l; P < 0.001). The aldosterone antagonist eplerenone prevented the sensitization of CTGF by aldosterone (control EC50 = 33.2 ± 1.7 mmol/l; aldosterone+eplerenone EC50 = 33.5 ± 1.3 mmol/l; n = 7). The GPR30 receptor blocker G-36 blocked the sensitization of CTGF by aldosterone (aldosterone EC50 = 16.5 ± 1.9 mmol/l; aldosterone+G-36 EC50 = 29.0 ± 2.1 mmol/l; n = 7; P < 0.001). Finally, we found that the sensitization of CTGF by aldosterone was mediated, at least in part, by the sodium/hydrogen exchanger (NHE). We conclude that aldosterone in the CNT lumen sensitizes CTGF via a nongenomic effect involving GPR30 receptors and NHE. Sensitized CTGF induced by aldosterone may contribute to renal damage by increasing Af-Art dilation and glomerular capillary pressure (glomerular barotrauma). PMID:24966088

Investigating Added Value of Regional Climate Modeling in North American Winter Storm Track Simulations

NASA Astrophysics Data System (ADS)

Poan, E.; Gachon, P., Sr.; Laprise, R.; Aider, R.; Dueymes, G.

2017-12-01

This study describes a framework using possibilities given by regional climate models (RCMs) to gain insight into extratropical cyclone (EC) activity during winter over North America (NA). Recent past climate period (1981 - 2005) is firstly considered using the NCEP regional reanalysis (NARR) as a reference, along with the European global reanalysis ERA-Interim (ERAI) and two CMIP5 Global Climate Models (GCMs) used to drive the Canadian RCM - version 5 (CRCM5) and the corresponding regional-scale simulations. While ERAI and GCM simulations show basic agreement with NARR in terms of climatological EC track patterns, detailed bias analyses show that, on the one hand, ERAI presents statistically significant positive biases in terms of EC genesis and therefore occurrence while their intensity is well captured. On the other hand, GCMs present large negative intensity biases in the overall NA domain and particularly over the eastern coast. In addition, storm occurrence from GCMs over the northwestern topographic regions is highly overestimated. When the CRCM5 is driven by ERAI, no significant skill deterioration arises and, more importantly, all storm characteristics near areas with main relief and over regions with large water masses are significantly improved with respect to ERAI. Conversely, in GCM-driven simulations, the added value from the CRCM5 is less prominent and systematic, except over western areas with high topography and over the Western Atlantic coastlines where the most frequent and intense ECs are located. Finally, time period near the end of the 21st century (2071-2100) is considered to analyze EC characteristic trends and changes relative to the current climate conditions, showing important modifications in storm activity for certain winter months, especially in term of intensity over the eastern coast.

Comparative sensitivity of Crassostrea angulata and Crassostrea gigas embryo-larval development to As under varying salinity and temperature.

PubMed

Moreira, Anthony; Figueira, Etelvina; Libralato, Giovanni; Soares, Amadeu M V M; Guida, Marco; Freitas, Rosa

2018-06-07

Oysters are a diverse group of marine bivalves that inhabit coastal systems of the world's oceans, providing a variety of ecosystem services, and represent a major socioeconomic resource. However, oyster reefs have become inevitably impacted from habitat destruction, overfishing, pollution and disease outbreaks that have pushed these structures to the break of extinction. In addition, the increased frequency of climate change related events promise to further challenge oyster species survival worldwide. Oysters' early embryonic development is likely the most vulnerable stage to climate change related stressors (e.g. salinity and temperature shifts) as well as to pollutants (e.g. arsenic), and therefore can represent the most important bottleneck that define populations' survival in a changing environment. In light of this, the present study aimed to assess two important oyster species, Crassostrea angulata and Crassostrea gigas embryo-larval development, under combinations of salinity (20, 26 and 33), temperature (20, 24 and 28 °C) and arsenic (As) exposure (0, 30, 60, 120, 240, 480, 960 and 1920 μg. As L -1 ), to infer on different oyster species capacity to cope with these environmental stressors under the eminent threat of climate change and increase of pollution worldwide. Results showed differences in each species range of salinity and temperature for successful embryonic development. For C angulata, embryo-larval development was successful at a narrower range of both salinity and temperature, compared to C. gigas. Overall, As induced higher toxicity to C. angulata embryos, with calculated EC50 values at least an order of magnitude lower than those calculated for C. gigas. The toxicity of As (measured as median effective concentration, EC50) showed to be influenced by both salinity and temperature in both species. Nonetheless, salinity had a greater influence on embryos' sensitivity to As. This pattern was mostly noticed for C. gigas, with lower salinity inducing higher sensitivity to As. Results were discussed considering the existing literature and suggest that C. angulata populations are likely to become more vulnerable under near future predictions for temperature rise, salinity shifts and pollution. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Diagnostic values of salivary versus and plasma microRNA-21 for early esophageal cancer].

PubMed

Ye, Minhua; Ye, Penghui; Zhang, Weizhu; Rao, Jiaqi; Xie, Zijun

2014-06-01

To evaluate the diagnostic value of salivary and plasma miR-21 in patients with esophageal cancer (EC). Total RNA was extracted from saliva and plasma samples from 50 stage I and 50 stage II patients with EC and 50 healthy controls for measurement of miR-21 levels using qPCR. The diagnostic values of salivary and plasma miR-21 levels were assessed for stage I, stage II, and stage I+II EC. Salivary and plasma miR-21 were significantly higher in the EC patients than in the control group. The diagnostic sensitivities of plasma miR-21 for stage I, stage II, and stage I+II EC were 96%, 64% and 97%, with specificities of 44%, 84%, and 56%, respectively; the sensitivities of salivary miR-21 were 90%, 88%, and 89%, respectively, with the same specificities of 64%. Regardless of EC staging, the expression of plasma miR-21 showed a significant positive correlation with that of salivary miR-21, and their diagnostic values were comparable. Both salivary and plasmatic miR-21 can be sensitive biomarkers for EC, and salivary miR-21 detection has the potential to replace plasma detection for EC diagnosis.

A Phenomenological Study of Perceptions of Early Childhood Administrators Related to Transformational Leadership, Educational Paths, and Organizational Climate

ERIC Educational Resources Information Center

Hayes, Lori

2012-01-01

Early childhood (EC) administrators could be the most important contributors to quality experiences in EC settings; they are also responsible for the caliber of experiences for children and staff. A quality EC program is licensed and accredited with administrators who have professional preparation and work experience and can lead and manage EC…

Assessing global climate-terrestrial vegetation feedbacks on carbon and nitrogen cycling in the earth system model EC-Earth

NASA Astrophysics Data System (ADS)

Wårlind, David; Miller, Paul; Nieradzik, Lars; Söderberg, Fredrik; Anthoni, Peter; Arneth, Almut; Smith, Ben

2017-04-01

There has been great progress in developing an improved European Consortium Earth System Model (EC-Earth) in preparation for the Coupled Model Intercomparison Project Phase 6 (CMIP6) and the next Assessment Report of the IPCC. The new model version has been complemented with ocean biogeochemistry, atmospheric composition (aerosols and chemistry) and dynamic land vegetation components, and has been configured to use the recommended CMIP6 forcing data sets. These new components will give us fresh insights into climate change. This study focuses on the terrestrial biosphere component Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS) that simulates vegetation dynamics and compound exchange between the terrestrial biosphere and the atmosphere in EC-Earth. LPJ-GUESS allows for vegetation to dynamically evolve, depending on climate input, and in return provides the climate system and land surface scheme with vegetation-dependent fields such as vegetation types and leaf area index. We present the results of a study to examine the feedbacks between the dynamic terrestrial vegetation and the climate and their impact on the terrestrial ecosystem carbon and nitrogen cycles. Our results are based on a set of global, atmosphere-only historical simulations (1870 to 2014) with and without feedback between climate and vegetation and including or ignoring the effect of nitrogen limitation on plant productivity. These simulations show to what extent the addition degree of freedom in EC-Earth, introduced with the coupling of interactive dynamic vegetation to the atmosphere, has on terrestrial carbon and nitrogen cycling, and represent contributions to CMIP6 (C4MIP and LUMIP) and the EU Horizon 2020 project CRESCENDO.

Climate controls over ecosystem metabolism: insights from a fifteen-year inductive artificial neural network synthesis for a subalpine forest.

PubMed

Albert, Loren P; Keenan, Trevor F; Burns, Sean P; Huxman, Travis E; Monson, Russell K

2017-05-01

Eddy covariance (EC) datasets have provided insight into climate determinants of net ecosystem productivity (NEP) and evapotranspiration (ET) in natural ecosystems for decades, but most EC studies were published in serial fashion such that one study's result became the following study's hypothesis. This approach reflects the hypothetico-deductive process by focusing on previously derived hypotheses. A synthesis of this type of sequential inference reiterates subjective biases and may amplify past assumptions about the role, and relative importance, of controls over ecosystem metabolism. Long-term EC datasets facilitate an alternative approach to synthesis: the use of inductive data-based analyses to re-examine past deductive studies of the same ecosystem. Here we examined the seasonal climate determinants of NEP and ET by analyzing a 15-year EC time-series from a subalpine forest using an ensemble of Artificial Neural Networks (ANNs) at the half-day (daytime/nighttime) time-step. We extracted relative rankings of climate drivers and driver-response relationships directly from the dataset with minimal a priori assumptions. The ANN analysis revealed temperature variables as primary climate drivers of NEP and daytime ET, when all seasons are considered, consistent with the assembly of past studies. New relations uncovered by the ANN approach include the role of soil moisture in driving daytime NEP during the snowmelt period, the nonlinear response of NEP to temperature across seasons, and the low relevance of summer rainfall for NEP or ET at the same daytime/nighttime time step. These new results offer a more complete perspective of climate-ecosystem interactions at this site than traditional deductive analyses alone.

Correlation of hepatic fractional extracellular space using gadolinium enhanced MRI with liver stiffness using magnetic resonance elastography.

PubMed

Wells, Michael L; Moynagh, Michael R; Carter, Rickey E; Childs, Robert A; Leitch, Cameron E; Fletcher, Joel G; Yeh, Benjamin M; Venkatesh, Sudhakar K

2017-01-01

To compare MR hepatic fractional extracellular space (fECS) to liver stiffness (LS) with magnetic resonance elastography (MRE) for evaluation of liver fibrosis. 71 consecutive patients with suspected chronic liver disease underwent standard liver MRI with MR elastography and additional delayed Gd-DTPA-enhanced sequences at 5 and 10 min in order to calculate hepatic fECS (%) and LS (kilopascals, kPa). Two radiologists blinded to clinical history examined MR images and calculated fECS and LS in identical locations for every patient. Interobserver agreement was calculated using the intraclass correlation coefficient. Pearson's correlation was calculated for LS and fECS measures, as was the area under the receiver operatic curve (AUROC), sensitivity and specificity of fECS to predict liver stiffness ≥2.93 and ≥5 kPa. The sensitivity of fECS for detecting fibrosis was separately analyzed in the subgroup of patients without anatomic findings of cirrhosis. Substantial to excellent interobserver agreement for both LS and fECS measurements was seen with intraclass correlation of 0.88 (95% CI 0.81-0.92) for LS, 0.77 (95% CI 0.66-0.85) for fECS 5 and 0.76 (95% CI 0.64-0.84) for fECS 10 . A significant correlation was found between MRE and fECS 5 (r = 0.47, p < 0.0001) and fECS 10 (r = 0.44, p < 0.0001). The performance of fECS improved for detection of advanced fibrosis (≥5 kPa) with AUROC, sensitivity and specificity of 0.72, 38%, and 94% for fECS 5 and 0.72, 67%, and 66% for fECS 10 . fECS correlates modestly with MRE-determined LS. fECS at MRI is a simple calculation to perform and may represent a practical way to suggest the presence of fibrosis during routine liver evaluation.

Morphological plasticity of ectomycorrhizal short roots in Betula sp and Picea abies forests across climate and forest succession gradients: its role in changing environments

PubMed Central

Ostonen, Ivika; Rosenvald, Katrin; Helmisaari, Heljä-Sisko; Godbold, Douglas; Parts, Kaarin; Uri, Veiko; Lõhmus, Krista

2013-01-01

Morphological plasticity of ectomycorrhizal (EcM) short roots (known also as first and second order roots with primary development) allows trees to adjust their water and nutrient uptake to local environmental conditions. The morphological traits (MTs) of short-living EcM roots, such as specific root length (SRL) and area, root tip frequency per mass unit (RTF), root tissue density, as well as mean diameter, length, and mass of the root tips, are good indicators of acclimation. We investigated the role of EcM root morphological plasticity across the climate gradient (48–68°N) in Norway spruce (Picea abies (L.) Karst) and (53–66°N) birch (Betula pendula Roth., B. pubescens Ehrh.) forests, as well as in primary and secondary successional birch forests assuming higher plasticity of a respective root trait to reflect higher relevance of that characteristic in acclimation process. We hypothesized that although the morphological plasticity of EcM roots is subject to the abiotic and biotic environmental conditions in the changing climate; the tools to achieve the appropriate morphological acclimation are tree species-specific. Long-term (1994–2010) measurements of EcM roots morphology strongly imply that tree species have different acclimation-indicative root traits in response to changing environments. Birch EcM roots acclimated along latitude by changing mostly SRL [plasticity index (PI) = 0.60], while spruce EcM roots became adjusted by modifying RTF (PI = 0.68). Silver birch as a pioneer species must have a broader tolerance to environmental conditions across various environments; however, the mean PI of all MTs did not differ between early-successional birch and late-successional spruce. The differences between species in SRL, and RTF, diameter, and length decreased southward, toward temperate forests with more favorable growth conditions. EcM root traits reflected root-rhizosphere succession across forest succession stages. PMID:24032035

Morphological plasticity of ectomycorrhizal short roots in Betula sp and Picea abies forests across climate and forest succession gradients: its role in changing environments.

PubMed

Ostonen, Ivika; Rosenvald, Katrin; Helmisaari, Heljä-Sisko; Godbold, Douglas; Parts, Kaarin; Uri, Veiko; Lõhmus, Krista

2013-01-01

Morphological plasticity of ectomycorrhizal (EcM) short roots (known also as first and second order roots with primary development) allows trees to adjust their water and nutrient uptake to local environmental conditions. The morphological traits (MTs) of short-living EcM roots, such as specific root length (SRL) and area, root tip frequency per mass unit (RTF), root tissue density, as well as mean diameter, length, and mass of the root tips, are good indicators of acclimation. We investigated the role of EcM root morphological plasticity across the climate gradient (48-68°N) in Norway spruce (Picea abies (L.) Karst) and (53-66°N) birch (Betula pendula Roth., B. pubescens Ehrh.) forests, as well as in primary and secondary successional birch forests assuming higher plasticity of a respective root trait to reflect higher relevance of that characteristic in acclimation process. We hypothesized that although the morphological plasticity of EcM roots is subject to the abiotic and biotic environmental conditions in the changing climate; the tools to achieve the appropriate morphological acclimation are tree species-specific. Long-term (1994-2010) measurements of EcM roots morphology strongly imply that tree species have different acclimation-indicative root traits in response to changing environments. Birch EcM roots acclimated along latitude by changing mostly SRL [plasticity index (PI) = 0.60], while spruce EcM roots became adjusted by modifying RTF (PI = 0.68). Silver birch as a pioneer species must have a broader tolerance to environmental conditions across various environments; however, the mean PI of all MTs did not differ between early-successional birch and late-successional spruce. The differences between species in SRL, and RTF, diameter, and length decreased southward, toward temperate forests with more favorable growth conditions. EcM root traits reflected root-rhizosphere succession across forest succession stages.

Impacts of climate changes on ocean surface gravity waves over the eastern Canadian shelf

NASA Astrophysics Data System (ADS)

Guo, Lanli; Sheng, Jinyu

2017-05-01

A numerical study is conducted to investigate the impact of climate changes on ocean surface gravity waves over the eastern Canadian shelf (ECS). The "business-as-usual" climate scenario known as Representative Concentration Pathway RCP8.5 is considered in this study. Changes in the ocean surface gravity waves over the study region for the period 1979-2100 are examined based on 3 hourly ocean waves simulated by the third-generation ocean wave model known as WAVEWATCHIII. The wave model is driven by surface winds and ice conditions produced by the Canadian Regional Climate Model (CanRCM4). The whole study period is divided into the present (1979-2008), near future (2021-2050) and far future (2071-2100) periods to quantify possible future changes of ocean waves over the ECS. In comparison with the present ocean wave conditions, the time-mean significant wave heights ( H s ) are expected to increase over most of the ECS in the near future and decrease over this region in the far future period. The time-means of the annual 5% largest H s are projected to increase over the ECS in both near and far future periods due mainly to the changes in surface winds. The future changes in the time-means of the annual 5% largest H s and 10-m wind speeds are projected to be twice as strong as the changes in annual means. An analysis of inverse wave ages suggests that the occurrence of wind seas is projected to increase over the southern Labrador and central Newfoundland Shelves in the near future period, and occurrence of swells is projected to increase over other areas of the ECS in both the near and far future periods.

Rejection Sensitivity and Executive Control: Joint predictors of Borderline Personality features

PubMed Central

Ayduk, Özlem; Zayas, Vivian; Downey, Geraldine; Cole, Amy Blum; Shoda, Yuichi; Mischel, Walter

2008-01-01

Two studies tested the hypothesis that rejection sensitivity (RS) and executive control (EC) jointly predict borderline personality (BP) features. We expected high RS to be related to increased vulnerability for BP features specifically in people who also had difficulties in executive control (EC). Study 1 tested this hypothesis using a sample of college students (N = 379) whereas Study 2 (N = 104) was conducted using a community sample of adults. Both studies operationalized EC by a self-report measure. For a subsample in Study 2 (N = 80), ability to delay gratification at age 4 was also used as an early behavioral precursor of EC in adulthood. In both studies, high RS was associated with increased BP features among people low in self-reported EC. Among those high in self-reported EC, the relationship between RS and BP features was attenuated. Study 2 found parallel findings using preschool delay ability as a behavioral index of EC. These findings suggest that EC may protect high RS people against BP features. PMID:18496604

Climate SPHINX: High-resolution present-day and future climate simulations with an improved representation of small-scale variability

NASA Astrophysics Data System (ADS)

Davini, Paolo; von Hardenberg, Jost; Corti, Susanna; Subramanian, Aneesh; Weisheimer, Antje; Christensen, Hannah; Juricke, Stephan; Palmer, Tim

2016-04-01

The PRACE Climate SPHINX project investigates the sensitivity of climate simulations to model resolution and stochastic parameterization. The EC-Earth Earth-System Model is used to explore the impact of stochastic physics in 30-years climate integrations as a function of model resolution (from 80km up to 16km for the atmosphere). The experiments include more than 70 simulations in both a historical scenario (1979-2008) and a climate change projection (2039-2068), using RCP8.5 CMIP5 forcing. A total amount of 20 million core hours will be used at end of the project (March 2016) and about 150 TBytes of post-processed data will be available to the climate community. Preliminary results show a clear improvement in the representation of climate variability over the Euro-Atlantic following resolution increase. More specifically, the well-known atmospheric blocking negative bias over Europe is definitely resolved. High resolution runs also show improved fidelity in representation of tropical variability - such as the MJO and its propagation - over the low resolution simulations. It is shown that including stochastic parameterization in the low resolution runs help to improve some of the aspects of the MJO propagation further. These findings show the importance of representing the impact of small scale processes on the large scale climate variability either explicitly (with high resolution simulations) or stochastically (in low resolution simulations).

Air-Quality and Climate Coupling in High Resolution for Urban Heat Island Study

NASA Astrophysics Data System (ADS)

Halenka, T.; Huszar, P.; Belda, M.

2012-04-01

Recent studies show considerable effect of atmospheric chemistry and aerosols on climate on regional and local scale. For the purpose of qualifying and quantifying the magnitude of climate forcing due to atmospheric chemistry/aerosols on regional scale and climate change effects on air-quality the regional climate model RegCM and chemistry/aerosol model CAMx was coupled. Climate change impacts on air-quality have been studied in high resolution of 10km with interactive two-way coupling of the effects of air-quality on climate. The experiments with the couple were performed for EC FP7 project MEGAPOLI assessing the impact of the megacities and industrialized areas on climate. New experiments in high resolution are prepared andsimulated for Urban Heat Island studies within the OP Central Europe Project UHI. Meteorological fields generated by RCM drive CAMx transport, chemistry and a dry/wet deposition. A preprocessor utility was developed for transforming RegCM provided fields to CAMx input fields and format. There is critical issue of the emission inventories available for 10km resolution including the urban hot-spots, TNO emissions are adopted for the experiments. Sensitivity tests switching on/off urban areas emissions are analysed as well. The results for year 2005 are presented and discussed, interactive coupling is compared to study the potential of possible impact of urban air-pollution to the urban area climate.

Comparative sensitizing potencies of fragrances, preservatives, and hair dyes.

PubMed

Lidén, Carola; Yazar, Kerem; Johansen, Jeanne D; Karlberg, Ann-Therese; Uter, Wolfgang; White, Ian R

2016-11-01

The local lymph node assay (LLNA) is used for assessing sensitizing potential in hazard identification and risk assessment for regulatory purposes. Sensitizing potency on the basis of the LLNA is categorized into extreme (EC3 value of ≤0.2%), strong (>0.2% to ≤2%), and moderate (>2%). To compare the sensitizing potencies of fragrance substances, preservatives, and hair dye substances, which are skin sensitizers that frequently come into contact with the skin of consumers and workers, LLNA results and EC3 values for 72 fragrance substances, 25 preservatives and 107 hair dye substances were obtained from two published compilations of LLNA data and opinions by the Scientific Committee on Consumer Safety and its predecessors. The median EC3 values of fragrances (n = 61), preservatives (n = 19) and hair dyes (n = 59) were 5.9%, 0.9%, and 1.3%, respectively. The majority of sensitizing preservatives and hair dyes are thus strong or extreme sensitizers (EC3 value of ≤2%), and fragrances are mostly moderate sensitizers. Although fragrances are typically moderate sensitizers, they are among the most frequent causes of contact allergy. This indicates that factors other than potency need to be addressed more rigorously in risk assessment and risk management. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Running climate model on a commercial cloud computing environment: A case study using Community Earth System Model (CESM) on Amazon AWS

NASA Astrophysics Data System (ADS)

Chen, Xiuhong; Huang, Xianglei; Jiao, Chaoyi; Flanner, Mark G.; Raeker, Todd; Palen, Brock

2017-01-01

The suites of numerical models used for simulating climate of our planet are usually run on dedicated high-performance computing (HPC) resources. This study investigates an alternative to the usual approach, i.e. carrying out climate model simulations on commercially available cloud computing environment. We test the performance and reliability of running the CESM (Community Earth System Model), a flagship climate model in the United States developed by the National Center for Atmospheric Research (NCAR), on Amazon Web Service (AWS) EC2, the cloud computing environment by Amazon.com, Inc. StarCluster is used to create virtual computing cluster on the AWS EC2 for the CESM simulations. The wall-clock time for one year of CESM simulation on the AWS EC2 virtual cluster is comparable to the time spent for the same simulation on a local dedicated high-performance computing cluster with InfiniBand connections. The CESM simulation can be efficiently scaled with the number of CPU cores on the AWS EC2 virtual cluster environment up to 64 cores. For the standard configuration of the CESM at a spatial resolution of 1.9° latitude by 2.5° longitude, increasing the number of cores from 16 to 64 reduces the wall-clock running time by more than 50% and the scaling is nearly linear. Beyond 64 cores, the communication latency starts to outweigh the benefit of distributed computing and the parallel speedup becomes nearly unchanged.

Environment degradation, economic growth and energy consumption nexus: A wavelet-windowed cross correlation approach

NASA Astrophysics Data System (ADS)

Jammazi, Rania; Aloui, Chaker

2015-10-01

This paper analyzes the interactive linkages between carbon dioxide (CO2) emissions, energy consumption (EC) and economic growth (EG) using a novel approach namely wavelet windowed cross correlation (WWCC) for six oil-exporting countries from the GCC (Gulf Cooperation Council) region over the period 1980-2012. Our empirical results show that there exists a bidirectional causal relationship between EC and EG. However, the results support the occurrence of unidirectional causality from EC to CO2 emissions without any feedback effects, and there exists a bidirectional causal relationship between EG and CO2 emissions for the region as a whole. The study suggests that environmental and energy policies should recognize the differences in the nexus between EC and EG in order to maintain sustainable EG in the GCC region. Our findings will be useful for GCC countries to better evaluate its situation in the future climate negotiations. The overall findings will help GCC countries assess its position better in future climate change negotiations.

Evaluating atmospheric blocking in the global climate model EC-Earth

NASA Astrophysics Data System (ADS)

Hartung, Kerstin; Hense, Andreas; Kjellström, Erik

2013-04-01

Atmospheric blocking is a phenomenon of the midlatitudal troposphere, which plays an important role in climate variability. Therefore a correct representation of blocking in climate models is necessary, especially for evaluating the results of climate projections. In my master's thesis a validation of blocking in the coupled climate model EC-Earth is performed. Blocking events are detected based on the Tibaldi-Molteni Index. At first, a comparison with the reanalysis dataset ERA-Interim is conducted. The blocking frequency depending on longitude shows a small general underestimation of blocking in the model - a well known problem. Scaife et al. (2011) proposed the correction of model bias as a way to solve this problem. However, applying the correction to the higher resolution EC-Earth model does not yield any improvement. Composite maps show a link between blocking events and surface variables. One example is the formation of a positive surface temperature anomaly north and a negative anomaly south of the blocking anticyclone. In winter the surface temperature in EC-Earth can be reproduced quite well, but in summer a cold bias over the inner-European ocean is present. Using generalized linear models (GLMs) I want to study the connection between regional blocking and global atmospheric variables further. GLMs have the advantage of being applicable to non-Gaussian variables. Therefore the blocking index at each longitude, which is Bernoulli distributed, can be analysed statistically with GLMs. I applied a logistic regression between the blocking index and the geopotential height at 500 hPa to study the teleconnection of blocking events at midlatitudes with global geopotential height. GLMs also offer the possibility of quantifying the connections shown in composite maps. The implementation of the logistic regression can even be expanded to a search for trends in blocking frequency, for example in the scenario simulations.

Simulation of tropospheric chemistry and aerosols with the climate model EC-Earth

NASA Astrophysics Data System (ADS)

van Noije, T. P. C.; Le Sager, P.; Segers, A. J.; van Velthoven, P. F. J.; Krol, M. C.; Hazeleger, W.

2014-03-01

We have integrated the atmospheric chemistry and transport model TM5 into the global climate model EC-Earth version 2.4. We present an overview of the TM5 model and the two-way data exchange between TM5 and the integrated forecasting system (IFS) model from the European Centre for Medium-Range Weather Forecasts (ECMWF), the atmospheric general circulation model of EC-Earth. In this paper we evaluate the simulation of tropospheric chemistry and aerosols in a one-way coupled configuration. We have carried out a decadal simulation for present-day conditions and calculated chemical budgets and climatologies of tracer concentrations and aerosol optical depth. For comparison we have also performed offline simulations driven by meteorological fields from ECMWF's ERA-Interim reanalysis and output from the EC-Earth model itself. Compared to the offline simulations, the online-coupled system produces more efficient vertical mixing in the troposphere, which likely reflects an improvement of the treatment of cumulus convection. The chemistry in the EC-Earth simulations is affected by the fact that the current version of EC-Earth produces a cold bias with too dry air in large parts of the troposphere. Compared to the ERA-Interim driven simulation, the oxidizing capacity in EC-Earth is lower in the tropics and higher in the extratropics. The methane lifetime is 7% higher in EC-Earth, but remains well within the range reported in the literature. We evaluate the model by comparing the simulated climatologies of surface carbon monoxide, tropospheric and surface ozone, and aerosol optical depth against observational data. The work presented in this study is the first step in the development of EC-Earth into an Earth system model with fully interactive atmospheric chemistry and aerosols.

Comparative sensitivity of the cnidarian Exaiptasia pallida and a standard toxicity test suite: testing whole effluents intended for ocean disposal.

PubMed

Howe, P L; Reichelt-Brushett, A J; Krassoi, R; Micevska, T

2015-09-01

The sea anemone Exaiptasia pallida (formally Aiptasia pulchella) has been identified as a valuable test species for tropical marine ecotoxicology. Here, the sensitivities of newly developed endpoints for E. pallida to two unidentified whole effluents were compared to a standard suite of temperate toxicity test species and endpoints that are commonly used in toxicological risk assessments for tropical marine environments. For whole effluent 1 (WE1), a 96-h lethal concentration 50 % (LC50) of 40 (95 % confidence intervals, 30-54) % v/v and a 12-day LC50 of 12 (9-15) % v/v were estimated for E. pallida, exhibiting a significantly higher sensitivity than standard sub-lethal endpoints in Allorchestes compressa (96-h effective concentration 50 % (EC50) of >100 % v/v for immobilisation) and Hormosira banksii (72-h EC50 of >100 % v/v for germination), and a similar sensitivity to Mytilus edulis galloprovincialis larval development with a 48-h LC50 of 29 (28-30) % v/v. Sub-lethal effects of whole effluent 2 (WE2) on E. pallida pedal lacerate development resulted in an 8-day EC50 of 7 (3-11) % v/v, demonstrating comparable sensitivity of this endpoint to standardised sub-lethal endpoints in H. banksii (72-h EC50 of 11 (10-11) % v/v for germination), M. edulis galloprovincialis (48-h EC50 for larval development of 12 (9-14) % v/v) and Heliocidaris tuberculata (1-h EC50 of 13 (12-14) % v/v for fertilisation; 72-h EC50 of 26 (25-27) % v/v for larval development) and a significantly higher sensitivity than A. compressa immobilisation (96-h EC50 of >100 % v/v). The sensitivity of E. pallida compared to a standard test species suite highlights the value in standardising the newly developed toxicity test methods for inclusion in routine toxicological risk assessment of complex whole effluents. Importantly, this species provides an additional taxonomic group to the test species that are currently available for tropical marine ecotoxicology and, being a cnidarian, may represent important tropical marine environments including coral reefs.

Computed tomography detection of extracapsular spread of squamous cell carcinoma of the head and neck in metastatic cervical lymph nodes.

PubMed

Carlton, Joshua A; Maxwell, Adam W; Bauer, Lyndsey B; McElroy, Sara M; Layfield, Lester J; Ahsan, Humera; Agarwal, Ajay

2017-06-01

Background and purpose In patients with squamous cell carcinoma of the head and neck (HNSCC), extracapsular spread (ECS) of metastases in cervical lymph nodes affects prognosis and therapy. We assessed the accuracy of intravenous contrast-enhanced computed tomography (CT) and the utility of imaging criteria for preoperative detection of ECS in metastatic cervical lymph nodes in patients with HNSCC. Materials and methods Preoperative intravenous contrast-enhanced neck CT images of 93 patients with histopathological HNSCC metastatic nodes were retrospectively assessed by two neuroradiologists for ECS status and ECS imaging criteria. Radiological assessments were compared with histopathological assessments of neck dissection specimens, and interobserver agreement of ECS status and ECS imaging criteria were measured. Results Sensitivity, specificity, positive predictive value, and accuracy for overall ECS assessment were 57%, 81%, 82% and 67% for observer 1, and 66%, 76%, 80% and 70% for observer 2, respectively. Correlating three or more ECS imaging criteria with histopathological ECS increased specificity and positive predictive value, but decreased sensitivity and accuracy. Interobserver agreement for overall ECS assessment demonstrated a kappa of 0.59. Central necrosis had the highest kappa of 0.74. Conclusion CT has moderate specificity for ECS assessment in HNSCC metastatic cervical nodes. Identifying three or more ECS imaging criteria raises specificity and positive predictive value, therefore preoperative identification of multiple criteria may be clinically useful. Interobserver agreement is moderate for overall ECS assessment, substantial for central necrosis. Other ECS CT criteria had moderate agreement at best and therefore should not be used individually as criteria for detecting ECS by CT.

Refractory testicular germ cell tumors are highly sensitive to the second generation DNA methylation inhibitor guadecitabine.

PubMed

Albany, Costantine; Hever-Jardine, Mary P; von Herrmann, Katherine M; Yim, Christina Y; Tam, Janice; Warzecha, Joshua M; Shin, Leah; Bock, Sarah E; Curran, Brian S; Chaudhry, Aneeq S; Kim, Fred; Sandusky, George E; Taverna, Pietro; Freemantle, Sarah J; Christensen, Brock C; Einhorn, Lawrence H; Spinella, Michael J

2017-01-10

Testicular germ cell tumors (TGCTs) are the most common cancers of young males. A substantial portion of TGCT patients are refractory to cisplatin. There are no effective therapies for these patients, many of whom die from progressive disease. Embryonal carcinoma (EC) are the stem cells of TGCTs. In prior in vitro studies we found that EC cells were highly sensitive to the DNA methyltransferase inhibitor, 5-aza deoxycytidine (5-aza). Here, as an initial step in bringing demethylation therapy to the clinic for TGCT patients, we evaluated the effects of the clinically optimized, second generation demethylating agent guadecitabine (SGI-110) on EC cells in an animal model of cisplatin refractory testicular cancer. EC cells were exquisitely sensitive to guadecitabine and the hypersensitivity was dependent on high levels of DNA methyltransferase 3B. Guadecitabine mediated transcriptional reprogramming of EC cells included induction of p53 targets and repression of pluripotency genes. As a single agent, guadecitabine completely abolished progression and induced complete regression of cisplatin resistant EC xenografts even at doses well below those required to impact somatic solid tumors. Low dose guadecitabine also sensitized refractory EC cells to cisplatin in vivo. Genome-wide analysis indicated that in vivo antitumor activity was associated with activation of p53 and immune-related pathways and the antitumor effects of guadecitabine were dependent on p53, a gene rarely mutated in TGCTs. These preclinical findings suggest that guadecitabine alone or in combination with cisplatin is a promising strategy to treat refractory TGCT patients.

Electrocorticographic high gamma activity versus electrical cortical stimulation mapping of naming.

PubMed

Sinai, Alon; Bowers, Christopher W; Crainiceanu, Ciprian M; Boatman, Dana; Gordon, Barry; Lesser, Ronald P; Lenz, Frederick A; Crone, Nathan E

2005-07-01

Subdural electrocorticographic (ECoG) recordings in patients undergoing epilepsy surgery have shown that functional activation is associated with event-related broadband gamma activity in a higher frequency range (>70 Hz) than previously studied in human scalp EEG. To investigate the utility of this high gamma activity (HGA) for mapping language cortex, we compared its neuroanatomical distribution with functional maps derived from electrical cortical stimulation (ECS), which remains the gold standard for predicting functional impairment after surgery for epilepsy, tumours or vascular malformations. Thirteen patients had undergone subdural electrode implantation for the surgical management of intractable epilepsy. Subdural ECoG signals were recorded while each patient verbally named sequentially presented line drawings of objects, and estimates of event-related HGA (80-100 Hz) were made at each recording site. Routine clinical ECS mapping used a subset of the same naming stimuli at each cortical site. If ECS disrupted mouth-related motor function, i.e. if it affected the mouth, lips or tongue, naming could not be tested with ECS at the same cortical site. Because naming during ECoG involved these muscles of articulation, the sensitivity and specificity of ECoG HGA were estimated relative to both ECS-induced impairments of naming and ECS disruption of mouth-related motor function. When these estimates were made separately for 12 electrode sites per patient (the average number with significant HGA), the specificity of ECoG HGA with respect to ECS was 78% for naming and 81% for mouth-related motor function, and equivalent sensitivities were 38% and 46%, respectively. When ECS maps of naming and mouth-related motor function were combined, the specificity and sensitivity of ECoG HGA with respect to ECS were 84% and 43%, respectively. This study indicates that event-related ECoG HGA during confrontation naming predicts ECS interference with naming and mouth-related motor function with good specificity but relatively low sensitivity. Its favourable specificity suggests that ECoG HGA can be used to construct a preliminary functional map that may help identify cortical sites of lower priority for ECS mapping. Passive recordings of ECoG gamma activity may be done simultaneously at all electrode sites without the risk of after-discharges associated with ECS mapping, which must be done sequentially at pairs of electrodes. We discuss the relative merits of these two functional mapping techniques.

Chemokines additional to IFN-γ can be used to differentiate among Mycobacterium tuberculosis infection possibilities and provide evidence of an early clearance phenotype.

PubMed

Nonghanphithak, Ditthawat; Reechaipichitkul, Wipa; Namwat, Wises; Naranbhai, Vivek; Faksri, Kiatichai

2017-07-01

Current diagnostic tests for tuberculosis (TB) remain limited in their ability to discriminate between active TB (ATB) and latent TB infection (LTBI). Early clearance (EC) of TB by individuals exposed to Mycobacterium tuberculosis is a debated phenomenon for which evidence is lacking. We measured and compared secreted chemokines in the plasma fraction from 48 ATB, 38 LTBI, 162 presumed EC and 39 healthy controls (HC) using the QuantiFERON ® -TB Gold In-Tube assay. Single chemokine markers were limited in their ability to discriminate between ATB and LTBI: IFN-γ showed 16.7% sensitivity; CCL2 showed moderate sensitivity (70.8%) and specificity (74.4%); CXCL10 showed high sensitivity (87.5%) and specificity (78.9%). Compared to IFN-γ alone, IFN-γ combined with CXCL10 significantly improved (p < 0.001) the sensitivity and specificity to discriminate between ATB and HC (97.9% sensitivity and 94.9% specificity) and between ATB and LTBI (89.6% sensitivity and 71.1% specificity). Levels of CCL2 were very significantly lower (p < 0.0001) in EC compared to HC groups and hence CCL2 is a useful marker for EC. This study demonstrated the potential application of profiling using multiple chemokines for differentiating among the various M. tuberculosis infection possibilities. We also present evidence to support the EC phenomenon based on the decrease of CCL2 levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study on chemotherapeutic sensitizing effect of nimotuzumab on different human esophageal squamous carcinoma cells.

PubMed

Yang, Xiaoyu; Ji, Yinghua; Kang, Xiaochun; Chen, Meiling; Kou, Weizheng; Jin, Cailing; Lu, Ping

2016-02-01

Esophageal cancer is one of the leading causes of mortality worldwide. Although, surgery, radio- and chemotherapy are used to treat the disease, the identification of new drugs is crucial to increase the curative effect. The aim of the present study was to examine the chemotherapeutic sensitizing effect of nimotuzumab (h-R3) and cisplatin cytotoxic drugs cisplatin (DDP) and 5-fluorouracil (5-FU) on esophageal carcinoma cells with two different epidermal growth factor receptor (EGFR) expressions. The expression of EGFR was detected in the human EC1 or EC9706 esophageal squamous cell carcinoma cell line using immunohistochemistry. The inhibitory effect of DDP and 5-FU alone or combined with h-R3 on EC1 or EC9706 cell proliferation was detected using an MTT assay. Flow cytometry and the TUNEL assay were used to determine the effect of single or combined drug treatment on cell apoptosis. The results showed that the expression of EGFR was low in EC1 cells but high in EC9706 cells. The inhibitory effect of the single use of h-R3 on EC1 or EC9706 cell proliferation was decreased. The inhibitory effect between single use of h-R3 alone and combined use of the chemotherapy drugs showed no statistically significant difference (P>0.05) on the EC1 cell growth rate, but showed a statistically significant difference (a=0.05) on EC9706 cell growth rate. The results detected by flow cytometry and TUNEL assay showed that the difference between single use of h-R3 alone and the control group was statistically significant with regard to the EC1 apoptosis rate effect (P<0.05), but not statistically significant for EC9706 (P>0.05). However, statistically significant differences were identified in the apoptotic rate of EC9706 cells between the h-R3 combined chemotherapy group and single chemotherapy group (P<0.05), but not on in the EC1 chemotherapy group (P>0.05). In conclusion, the sensitization effect of h-R3 on chemotherapy drugs is associated with the expression level of EGFR in EC1 or EC9706 cells. The cell killing effect of the combined use of h-R3 with DDP and 5-FU showed no obvious synergistic effect compared to the single-drug group, but only an additive effect.

Atmospheric impacts of black carbon emission reductions through the strategic use of biodiesel in California.

PubMed

Zhang, Hongliang; Magara-Gomez, Kento T; Olson, Michael R; Okuda, Tomoaki; Walz, Kenneth A; Schauer, James J; Kleeman, Michael J

2015-12-15

The use of biodiesel as a replacement for petroleum-based diesel fuel has gained interest as a strategy for greenhouse gas emission reductions, energy security, and economic advantage. Biodiesel adoption may also reduce particulate elemental carbon (EC) emissions from conventional diesel engines that are not equipped with after-treatment devices. This study examines the impact of biodiesel blends on EC emissions from a commercial off-road diesel engine and simulates the potential public health benefits and climate benefits. EC emissions from the commercial off-road engine decreased by 76% when ultra-low sulfur commercial diesel (ULSD) fuel was replaced by biodiesel. Model calculations predict that reduced EC emissions translate directly into reduced EC concentrations in the atmosphere, but the concentration of secondary particulate matter was not directly affected by this fuel change. Redistribution of secondary particulate matter components to particles emitted from other sources did change the size distribution and therefore deposition rates of those components. Modification of meteorological variables such as water content and temperature influenced secondary particulate matter formation. Simulations with a source-oriented WRF/Chem model (SOWC) for a severe air pollution episode in California that adopted 75% biodiesel blended with ULSD in all non-road diesel engines reduced surface EC concentrations by up to 50% but changed nitrate and total PM2.5 mass concentrations by less than ±5%. These changes in concentrations will have public health benefits but did not significantly affect radiative forcing at the top of the atmosphere. The removal of EC due to the adoption of biodiesel produced larger coatings of secondary particulate matter on other atmospheric particles containing residual EC leading to enhanced absorption associated with those particles. The net effect was a minor change in atmospheric optical properties despite a large change in atmospheric EC concentrations. These results emphasize the importance of considering EC mixing state in climate research. Copyright © 2015. Published by Elsevier B.V.

Simulation-based performance analysis of EC-Earth 3.2.0 using Dimemas

NASA Astrophysics Data System (ADS)

Yepes Arbós, Xavier; César Acosta Cobos, Mario; Serradell Maronda, Kim; Sanchez Lorente, Alicia; Doblas Reyes, Francisco Javier

2017-04-01

Earth System Models (ESMs) are complex applications executed in supercomputing facilities due to their high demand on computing resources. However, not all these models perform a good resources usage and the energy efficiency can be well below a minimum acceptable. One example is EC-Earth, a global coupled climate model which integrates different component models to simulate the Earth system. The two main components used in this analysis are IFS as atmospheric model and NEMO as ocean model, both coupled via the OASIS3-MCT coupler. Preliminary results proved that EC-Earth does not have a good computational performance. For example, the scalability of this model using the T255L91 grid with 512 MPI processes for IFS and the ORCA1L75 grid with 128 MPI processes for NEMO achieves 40.3 of speedup. This means that the 81.2% of the resources are wasted. Therefore, it is necessary a performance analysis to find the bottlenecks of the model and thus, determine the most appropriate optimization techniques. Using traces of the model collected with profiling tools such as Extrae, Paraver and Dimemas, allow us to simulate the model behaviour on a configurable parallel platform and extrapolate the impact of hardware changes in the performance of EC-Earth. In this document we propose a state-of-art procedure which makes possible to evaluate the different characteristics of climate models in a very efficient way. Accordingly, the performance of EC-Earth in different scenarios, namely assuming an ideal machine, model sensitivity and limiting model due to coupling has been shown. By simulating these scenarios, we realized that each model has different characteristics. With the ideal machine, we have seen that there are some sources of inefficiency: about a 20.59% of the execution time is communication; and there are workload imbalances produced by data dependences both between IFS and NEMO and within each model. In addition, in the model sensitivity simulations, we have described the types of messages and detected data dependencies. In IFS, we have observed that latency affects the coupling between models due to a large amount of small communications, whereas bandwidth affects another region of the code with a few big messages. In NEMO, results show that the simulated latencies and bandwidths only affect slightly to its execution time. However, it has data dependencies solved inefficiently and workload imbalances. The last simulation performed to detect the slowest model due to coupling has revealed that IFS is slower than NEMO. Moreover, there is not enough bandwidth to transfer all the data in IFS, whereas in NEMO there is almost no contention. This study is useful to improve the computational efficiency of the model, adapt it to support ultra-high resolution (UHR) experiments and future exascale supercomputers, and help code developers to design new algorithms more machine-independent.

Allergic contact dermatitis from ethyl chloride and benzocaine.

PubMed

Carazo, Juan Luis Anguita; Morera, Blanca Sáenz de San Pedro; Colom, Luis Palacios; Gálvez Lozano, José Manuel

2009-01-01

Ethyl chloride (EC) or chloroethane (C2H5Cl) is a volatile halogenated hydrocarbon. Reports of contact sensitivity to this gas are infrequent considering its widespread use as a local anesthetic, and it may have a relatively low sensitization potential. Benzocaine is another local anesthetic derivative of the ethyl ester of para-aminobenzoic acid, previously reported as a causative agent of delayed hypersensitivity reactions. We present a patient who developed a generalized itching dermatitis after the application of a medical aerosol containing EC, as well as facial angioedema and tongue swelling after the local application of benzocaine. Patch-test results were positive for EC "as is" (++), benzocaine 5% in petrolatum (++), and caine mix (+++) at 96 hours (day 4). The possibility of cross-sensitization between both drugs would not have been chemically plausible. We report the first published clinical case of contact allergic dermatitis from two chemically unrelated local anesthetics (EC and benzocaine) in the same patient.

Translocation by T7 RNA polymerase: a sensitively poised Brownian ratchet.

PubMed

Guo, Qing; Sousa, Rui

2006-04-21

Studies of halted T7 RNA polymerase (T7RNAP) elongation complexes (ECs) or of T7RNAP transcription against roadblocks due to DNA-bound proteins indicate that T7RNAP translocates via a passive Brownian ratchet mechanism. Crystal structures of T7RNAP ECs suggest that translocation involves an active power-stroke. However, neither solution studies of halted or slowed T7RNAP ECs, nor crystal structures of static complexes, are necessarily relevant to how T7RNAP translocates during rapid elongation. A recent single molecule study of actively elongating T7RNAPs provides support for the Brownian ratchet mechanism. Here, we obtain additional evidence for the existence of a Brownian ratchet during active T7RNAP elongation by showing that both rapidly elongating and halted complexes are equally sensitive to pyrophosphate. Using chemical nucleases tethered to the polymerase we achieve sub-ångström resolution in measuring the average position of halted T7RNAP ECs and find that the positional equilibrium of the EC is sensitively poised between pre-translocated and post-translocated states. This may be important in maximizing the sensitivity of the polymerase to sequences that cause pausing or termination. We also confirm that a crystallographically observed disorder to order transition in a loop formed by residues 589-612 also occurs in solution and is coupled to pyrophosphate or NTP release. This transition allows the loop to make interactions with the DNA that help stabilize the laterally mobile, ligand-free EC against dissociation.

Acute sensitivity of white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) to copper, cadmium, or zinc in water-only laboratory exposures

USGS Publications Warehouse

Calfee, Robin D.; Little, Edward E.; Puglis, Holly J.; Scott, Erinn L.; Brumbaugh, William G.; Mebane, Christopher A.

2014-01-01

The acute toxicity of cadmium, copper, and zinc to white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) were determined for 7 developmental life stages in flow-through water-only exposures. Metal toxicity varied by species and by life stage. Rainbow trout were more sensitive to cadmium than white sturgeon across all life stages, with median effect concentrations (hardness-normalized EC50s) ranging from 1.47 µg Cd/L to 2.62 µg Cd/L with sensitivity remaining consistent during later stages of development. Rainbow trout at 46 d posthatch (dph) ranked at the 2nd percentile of a compiled database for Cd species sensitivity distribution with an EC50 of 1.46 µg Cd/L and 72 dph sturgeon ranked at the 19th percentile (EC50 of 3.02 µg Cd/L). White sturgeon were more sensitive to copper than rainbow trout in 5 of the 7 life stages tested with biotic ligand model (BLM)-normalized EC50s ranging from 1.51 µg Cu/L to 21.9 µg Cu/L. In turn, rainbow trout at 74 dph and 95 dph were more sensitive to copper than white sturgeon at 72 dph and 89 dph, indicating sturgeon become more tolerant in older life stages, whereas older trout become more sensitive to copper exposure. White sturgeon at 2 dph, 16 dph, and 30 dph ranked in the lower percentiles of a compiled database for copper species sensitivity distribution, ranking at the 3rd (2 dph), 5th (16 dph), and 10th (30 dph) percentiles. White sturgeon were more sensitive to zinc than rainbow trout for 1 out of 7 life stages tested (2 dph with an biotic ligand model–normalized EC50 of 209 µg Zn/L) and ranked in the 1st percentile of a compiled database for zinc species sensitivity distribution.

Toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus crypticus changes under a global warming perspective: Variations in air temperature and soil moisture content.

PubMed

González-Alcaraz, M Nazaret; van Gestel, Cornelis A M

2016-12-15

This study aimed to assess how the current global warming perspective, with increasing air temperature (20°C vs. 25°C) and decreasing soil moisture content (50% vs. 30% of the soil water holding capacity, WHC), affected the toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus crypticus. Enchytraeids were exposed for 21d to a dilution series of the agricultural soil with Lufa 2.2 control soil under four climate situations: 20°C+50% WHC (standard conditions), 20°C+30% WHC, 25°C+50% WHC, and 25°C+30% WHC. Survival, reproduction and bioaccumulation of As, Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn were obtained as endpoints. Reproduction was more sensitive to both climate factors and metal(loid) pollution. High soil salinity (electrical conductivity~3dSm -1 ) and clay texture, even without the presence of high metal(loid) concentrations, affected enchytraeid performance especially at drier conditions (≥80% reduction in reproduction). The toxicity of the agricultural soil increased at drier conditions (10% reduction in EC10 and EC50 values for the effect on enchytraeid reproduction). Changes in enchytraeid performance were accompanied by changes in As, Fe, Mn, Pb and Zn bioaccumulation, with lower body concentrations at drier conditions probably due to greater competition with soluble salts in the case of Fe, Mn, Pb and Zn. This study shows that apart from high metal(loid) concentrations other soil properties (e.g. salinity and texture) may be partially responsible for the toxicity of metal(loid)-polluted soils to soil invertebrates, especially under changing climate conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

The Interplay of Maternal Sensitivity and Gentle Control When Predicting Children's Subsequent Academic Functioning: Evidence of Mediation by Effortful Control

ERIC Educational Resources Information Center

Kopystynska, Olena; Spinrad, Tracy L.; Seay, Danielle M.; Eisenberg, Nancy

2016-01-01

The goal of this work was to examine the complex interrelation of mothers' early gentle control and sensitivity in predicting children's effortful control (EC) and academic functioning. Maternal gentle control, maternal sensitivity, and children's EC were measured when children were 18, 30, and 42 months of age (T1, T2, and T3, respectively), and…

Solar absorption by elemental and brown carbon determined from spectral observations.

PubMed

Bahadur, Ranjit; Praveen, Puppala S; Xu, Yangyang; Ramanathan, V

2012-10-23

Black carbon (BC) is functionally defined as the absorbing component of atmospheric total carbonaceous aerosols (TC) and is typically dominated by soot-like elemental carbon (EC). However, organic carbon (OC) has also been shown to absorb strongly at visible to UV wavelengths and the absorbing organics are referred to as brown carbon (BrC), which is typically not represented in climate models. We propose an observationally based analytical method for rigorously partitioning measured absorption aerosol optical depths (AAOD) and single scattering albedo (SSA) among EC and BrC, using multiwavelength measurements of total (EC, OC, and dust) absorption. EC is found to be strongly absorbing (SSA of 0.38) whereas the BrC SSA varies globally between 0.77 and 0.85. The method is applied to the California region. We find TC (EC + BrC) contributes 81% of the total absorption at 675 nm and 84% at 440 nm. The BrC absorption at 440 nm is about 40% of the EC, whereas at 675 nm it is less than 10% of EC. We find an enhanced absorption due to OC in the summer months and in southern California (related to forest fires and secondary OC). The fractions and trends are broadly consistent with aerosol chemical-transport models as well as with regional emission inventories, implying that we have obtained a representative estimate for BrC absorption. The results demonstrate that current climate models that treat OC as nonabsorbing are underestimating the total warming effect of carbonaceous aerosols by neglecting part of the atmospheric heating, particularly over biomass-burning regions that emit BrC.

Perception of emotional climate in a revolution: Test of a multistage theory of revolution in the Tunisian context.

PubMed

Rimé, Bernard; Yzerbyt, Vincent; Mahjoub, Abdelwahab

2017-12-01

Participation in social movements and collective action depends upon people's capacity to perceive their societal context. We examined this question in the context of Arab Spring revolutions. In a classic theory of revolution highlighting the role of collective emotions, Brinton (1938) claimed that revolutions, far from chaos, proceed in an orderly sequence involving four stages: euphoria, degradation, terror, and restoration. The emotional climate (EC) as perceived by ordinary Tunisian citizens (2,699 women and 3,816 men) was measured during the 4 years of the Tunisian revolution. A quadratic pattern of perceived EC measures over time provided strong support to Brinton's model. In addition, three different analyses suggested the presence of four distinct stages in the evolution of perceived EC. Third, the socio-political developments in Tunisia during the four stages proved entirely consistent with both Brinton's theoretical model and the perceived EC indicators. Finally, social identification proved closely related to the temporal evolution of positive EC scores. In sum, data from this study not only lend support to the views put forth in an heretofore untested classic theory of revolution but also demonstrate that psychosocial measurements can validly monitor a major process of socio-political transformation. © 2017 The British Psychological Society.

Microbial toxicity of methyl tert-butyl ether (MTBE) determined with fluorescent and luminescent bioassays.

PubMed

Roslev, Peter; Lentz, Trine; Hesselsoe, Martin

2015-02-01

The inhibitory effects of the fuel additive methyl tert-butyl ether (MTBE) and potential degradation products tert-butanol (TBA) and formaldehyde was examined using mixed microbial biomass, and six strains of bioluminescent bacteria and yeast. The purpose was to assess microbial toxicity with quantitative bioluminescent and fluorescent endpoints, and to identify sensitive proxies suitable for monitoring MTBE contamination. Bioluminescent Aliivibrio fischeri DSM 7151 (formerly Vibrio fischeri) appeared highly sensitive to MTBE exposure, and was a superior test organisms compared to lux-tagged Escherichia coli DH5α, Pseudomonas fluorescens DF57-40E7 and Saccharomyces cerevisiae BLYR. EC10 and EC50 for acute MTBE toxicity in A. fischeri were 1.1 and 10.9 mg L(-1), respectively. Long term (24h) MTBE exposure resulted in EC10 values of 0.01 mg L(-1). TBA was significantly less toxic with EC10 and EC50 for acute and chronic toxicity >1000 mg L(-1). Inhibition of bioluminescence was generally a more sensitive endpoint for MTBE toxicity than measuring intracellular ATP levels and heterotrophic CO2 assimilation. A weak estrogenic response was detected for MTBE at concentrations ⩾ 3.7 g L(-1) using an estrogen inducible bioluminescent yeast strain (S. cerevisiae BLYES). Microbial hydrolytic enzyme activity in groundwater was affected by MTBE with EC10 values of 0.5-787 mg L(-1), and EC50 values of 59-3073 for alkaline phosphatase, arylsulfatase, beta-1,4-glucanase, N-acetyl-beta-d-glucosaminidase, and leucine-aminopeptidase. Microbial alkaline phosphatase and beta-1,4-glucanase activity were most sensitive to MTBE exposure with EC50 ⩽ 64.8 mg L(-1). The study suggests that bioassays with luminescent A. fischeri, and fluorescent assays targeting hydrolytic enzyme activity are good candidates for monitoring microbial MTBE toxicity in contaminated water. Copyright © 2014 Elsevier Ltd. All rights reserved.

A chronic toxicity test for the tropical marine snail Nassarius dorsatus to assess the toxicity of copper, aluminium, gallium, and molybdenum.

PubMed

Trenfield, Melanie A; van Dam, Joost W; Harford, Andrew J; Parry, David; Streten, Claire; Gibb, Karen; van Dam, Rick A

2016-07-01

Chronic toxicity test methods for assessing the toxicity of contaminants to tropical marine organisms are generally lacking. A 96-h chronic growth rate toxicity test was developed for the larval stage of the tropical dogwhelk, Nassarius dorsatus. Growth rates of N. dorsatus larvae were assessed following exposures to copper (Cu), aluminium (Al), gallium (Ga), and molybdenum (Mo). Exposure to Cu at 28 °C validated the sensitivity of the test method, with 10% (EC10) and 50% (EC50) effect concentrations of 4.2 μg/L and 7.3 μg/L Cu, respectively. The EC10 and EC50 values for Al (<0.45-μm filtered fraction) at 28 °C were 115 μg/L and 185 μg/L, respectively. The toxicity of Cu and Al was also assessed at 24 °C and 31 °C, representing average year-round water temperatures for subtropical and tropical Australian coastal environments. At 24 °C, the growth rate of control larvae was reduced by 52% compared with the growth rate at 28 °C and there was an increase in sensitivity to Cu (EC50 = 4.7 μg/L) but a similar sensitivity to Al (EC50 = 180 μg/L). At 31 °C the control growth rate increased by 35% from that measured at 28 °C and there was reduced sensitivity to both Cu and Al (EC50s = 8.5 μg/L and 642 μg/L, respectively). There was minimal toxicity resulting from Ga (EC50 = 4560 μg/L) and Mo (no effect at ≤7000 μg/L Mo). Environ Toxicol Chem 2016;35:1788-1795. © 2015 SETAC. © 2015 SETAC.

The impact of vehicle on the relative potency of skin-sensitizing chemicals in the local lymph node assay.

PubMed

Jowsey, Ian R; Clapp, Catherine J; Safford, Bob; Gibbons, Ben T; Basketter, David A

2008-01-01

The identification and characterization of chemicals that possess skin-sensitizing potential are typically performed using predictive tests. However, human exposure to skin-sensitizing chemicals often occurs via a matrix (vehicle) that differs from that used in these tests. It is thus important to account for the potential impact of vehicle differences when undertaking quantitative risk assessment for skin sensitization. This is achieved through the application of a specific sensitization assessment factor (SAF), scaled between 1 and 10, when identifying an acceptable exposure level. The objective of the analysis described herein is to determine the impact of vehicle differences on local lymph node assay (LLNA) EC3 values (concentrations of test chemical required to provoke a 3-fold increase in lymph node cell proliferation). Initially, the inherent variability of the LLNA was investigated by examining the reproducibility of EC3 values for 14 chemicals that have been tested more than once in the same vehicle (4:1 acetone:olive oil, AOO). This analysis reveals that the variability in EC3 value for these chemicals following multiple assessments is <5-fold. Next, data from the literature and previously unpublished studies were compiled for 18 chemicals that had been assessed in the LLNA using at least 2 of 15 different vehicles. These data demonstrate that often the variability in EC3 values observed for a given chemical in different vehicles is no greater than the 5-fold inherent variability observed when assessing a chemical in the same vehicle on multiple occasions. However, there are examples where EC3 values for a chemical differ by a factor of more than 10 between different vehicles. These observations were often associated with an apparent underestimation of potency (higher EC3 values) with predominantly aqueous vehicles or propylene glycol. These data underscore the need to consider vehicle effects in the context of skin-sensitization risk assessments.

Budget analysis of Escherichia coli at a southern Lake Michigan Beach

USGS Publications Warehouse

Thupaki, P.; Phanikumar, M.S.; Beletsky, D.; Schwab, D.J.; Nevers, M.B.; Whitman, R.L.

2010-01-01

Escherichia coli (EC) concentrations at two beaches impacted by river plume dynamics in southern Lake Michigan were analyzed using three-dimensional hydrodynamic and transport models. The relative importance of various physical and biological processes influencing the fate and transport of EC were examined via budget analysis and a first-order sensitivity analysis of model parameters. The along-shore advective fluxofEC(CFU/m2·s)was found to be higher compared to its crossshore counterpart; however, the sum of diffusive and advective components was of a comparable magnitude in both directions showing the importance of cross-shore exchange in EC transport. Examination of individual terms in the EC mass balance equation showed that vertical turbulent mixing in the water column dominated the overall EC transport for the summer conditions simulated. Dilution due to advection and diffusion accounted for a large portion of the total EC budget in the nearshore, and the net EC loss rate within the water column (CFU/m3·s) was an order of magnitude smaller compared to the horizontal and vertical transport rates. This result has important implications for modeling EC at recreational beaches; however, the assessment of the magnitude of EC loss rate is complicated due to the strong coupling between vertical exchange and depth-dependent EC loss processes such as sunlight inactivation and settling. Sensitivity analysis indicated that solar inactivation has the greatest impact on EC loss rates. Although these results are site-specific, they clearly bring out the relative importance of various processes involved.

Genetic analyses place most Spanish isolates of Beauveria bassiana in a molecular group with word-wide distribution

PubMed Central

2011-01-01

Background The entomopathogenic anamorphic fungus Beauveria bassiana is currently used as a biocontrol agent (BCA) of insects. Fifty-seven Beauveria bassiana isolates -53 from Spain- were characterized, integrating group I intron insertion patterns at the 3'-end of the nuclear large subunit ribosomal gene (LSU rDNA) and elongation factor 1-alpha (EF1-α) phylogenetic information, in order to assess the genetic structure and diversity of this Spanish collection of B. bassiana. Results Group I intron genotype analysis was based on the four highly conserved insertion sites of the LSU (Ec2653, Ec2449, Ec2066, Ec1921). Of the 16 possible combinations/genotypes, only four were detected, two of which were predominant, containing 44 and 9 members out of 57 isolates, respectively. Interestingly, the members of the latter two genotypes showed unique differences in their growth temperatures. In follow, EF1-α phylogeny served to classify most of the strains in the B. bassiana s.s. (sensu stricto) group and separate them into 5 molecular subgroups, all of which contained a group I intron belonging to the IC1 subtype at the Ec1921 position. A number of parameters such as thermal growth or origin (host, geographic location and climatic conditions) were also examined but in general no association could be found. Conclusion Most Spanish B. bassiana isolates (77.2%) are grouped into a major phylogenetic subgroup with word-wide distribution. However, high phylogenetic diversity was also detected among Spanish isolates from close geographic zones with low climatic variation. In general, no correlation was observed between the molecular distribution and geographic origin or climatic characteristics where the Spanish B. bassiana isolates were sampled. PMID:21521527

Simulation of tropospheric chemistry and aerosols with the climate model EC-Earth

NASA Astrophysics Data System (ADS)

van Noije, T. P. C.; Le Sager, P.; Segers, A. J.; van Velthoven, P. F. J.; Krol, M. C.; Hazeleger, W.; Williams, A. G.; Chambers, S. D.

2014-10-01

We have integrated the atmospheric chemistry and transport model TM5 into the global climate model EC-Earth version 2.4. We present an overview of the TM5 model and the two-way data exchange between TM5 and the IFS model from the European Centre for Medium-Range Weather Forecasts (ECMWF), the atmospheric general circulation model of EC-Earth. In this paper we evaluate the simulation of tropospheric chemistry and aerosols in a one-way coupled configuration. We have carried out a decadal simulation for present-day conditions and calculated chemical budgets and climatologies of tracer concentrations and aerosol optical depth. For comparison we have also performed offline simulations driven by meteorological fields from ECMWF's ERA-Interim reanalysis and output from the EC-Earth model itself. Compared to the offline simulations, the online-coupled system produces more efficient vertical mixing in the troposphere, which reflects an improvement of the treatment of cumulus convection. The chemistry in the EC-Earth simulations is affected by the fact that the current version of EC-Earth produces a cold bias with too dry air in large parts of the troposphere. Compared to the ERA-Interim driven simulation, the oxidizing capacity in EC-Earth is lower in the tropics and higher in the extratropics. The atmospheric lifetime of methane in EC-Earth is 9.4 years, which is 7% longer than the lifetime obtained with ERA-Interim but remains well within the range reported in the literature. We further evaluate the model by comparing the simulated climatologies of surface radon-222 and carbon monoxide, tropospheric and surface ozone, and aerosol optical depth against observational data. The work presented in this study is the first step in the development of EC-Earth into an Earth system model with fully interactive atmospheric chemistry and aerosols.

Carbon fluxes in tropical forest ecosystems: the value of Eddy-covariance data for individual-based dynamic forest gap models

NASA Astrophysics Data System (ADS)

Roedig, Edna; Cuntz, Matthias; Huth, Andreas

2015-04-01

The effects of climatic inter-annual fluctuations and human activities on the global carbon cycle are uncertain and currently a major issue in global vegetation models. Individual-based forest gap models, on the other hand, model vegetation structure and dynamics on a small spatial (<100 ha) and large temporal scale (>1000 years). They are well-established tools to reproduce successions of highly-diverse forest ecosystems and investigate disturbances as logging or fire events. However, the parameterizations of the relationships between short-term climate variability and forest model processes are often uncertain in these models (e.g. daily variable temperature and gross primary production (GPP)) and cannot be constrained from forest inventories. We addressed this uncertainty and linked high-resolution Eddy-covariance (EC) data with an individual-based forest gap model. The forest model FORMIND was applied to three diverse tropical forest sites in the Amazonian rainforest. Species diversity was categorized into three plant functional types. The parametrizations for the steady-state of biomass and forest structure were calibrated and validated with different forest inventories. The parameterizations of relationships between short-term climate variability and forest model processes were evaluated with EC-data on a daily time step. The validations of the steady-state showed that the forest model could reproduce biomass and forest structures from forest inventories. The daily estimations of carbon fluxes showed that the forest model reproduces GPP as observed by the EC-method. Daily fluctuations of GPP were clearly reflected as a response to daily climate variability. Ecosystem respiration remains a challenge on a daily time step due to a simplified soil respiration approach. In the long-term, however, the dynamic forest model is expected to estimate carbon budgets for highly-diverse tropical forests where EC-measurements are rare.

[Impact of cork oak management on the ectomycorrhizal fungal diversity associated with Quercus suber in the Mâamora forest (Morocco)].

PubMed

Maghnia, Fatima Z; Sanguin, Hervé; Abbas, Younes; Verdinelli, Marcello; Kerdouh, Benaissa; El Ghachtouli, Naima; Lancellotti, Enrico; Bakkali Yakhlef, Salah Eddine; Duponnois, Robin

2017-05-01

The cork oak forest is an ecosystem playing a major role in Moroccan socio-economy and biodiversity conservation. However, this ecosystem is negatively impacted by extensive human- and climate-driven pressures, causing a strong decrease in its distribution and a worsening of the desertification processes. This study aims at characterising the impact of cork oak forest management on a major actor of its functioning, the ectomycorrhizal (EcM) fungal community associated with Quercus suber, and the determination of EcM bio-indicators. The EcM fungal community has been monitored during spring and winter seasons in two sites of the Moroccan Mâamora forest, corresponding to a forest site either impacted by human activities or protected. A significant impact of cork oak forest management on the EcM fungal community has been revealed, with major differences during the summer season. The results confirmed the potential ecological significance of several EcM fungi (e.g., Cenococcum) in the sustainability of the cork oak forest functioning, but also the significant association of certain EcM fungi (Pachyphloeus, Russula, Tomentella) with a perturbation or a season, and consequently to the cork oak forest status or to climatic conditions, respectively. The development of study at the Mediterranean scale may improve the robustness of ecological models to predict the impact of global changes on this emblematic ecosystem of Mediterranean basin. Copyright © 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

"Evolution Canyon," a potential microscale monitor of global warming across life.

PubMed

Nevo, Eviatar

2012-02-21

Climatic change and stress is a major driving force of evolution. The effects of climate change on living organisms have been shown primarily on regional and global scales. Here I propose the "Evolution Canyon" (EC) microscale model as a potential life monitor of global warming in Israel and the rest of the world. The EC model reveals evolution in action at a microscale involving biodiversity divergence, adaptation, and incipient sympatric speciation across life from viruses and bacteria through fungi, plants, and animals. The EC consists of two abutting slopes separated, on average, by 200 m. The tropical, xeric, savannoid, "African" south-facing slope (AS = SFS) abuts the forested "European" north-facing slope (ES = NFS). The AS receives 200-800% higher solar radiation than the ES. The ES represents the south European forested maquis. The AS and ES exhibit drought and shade stress, respectively. Major adaptations on the AS are because of solar radiation, heat, and drought, whereas those on the ES relate to light stress and photosynthesis. Preliminary evidence suggests the extinction of some European species on the ES and AS. In Drosophila, a 10-fold higher migration was recorded in 2003 from the AS to ES. I advance some predictions that could be followed in diverse species in EC. The EC microclimatic model is optimal to track global warming at a microscale across life from viruses and bacteria to mammals in Israel, and in additional ECs across the planet.

“Evolution Canyon,” a potential microscale monitor of global warming across life

PubMed Central

Nevo, Eviatar

2012-01-01

Climatic change and stress is a major driving force of evolution. The effects of climate change on living organisms have been shown primarily on regional and global scales. Here I propose the “Evolution Canyon” (EC) microscale model as a potential life monitor of global warming in Israel and the rest of the world. The EC model reveals evolution in action at a microscale involving biodiversity divergence, adaptation, and incipient sympatric speciation across life from viruses and bacteria through fungi, plants, and animals. The EC consists of two abutting slopes separated, on average, by 200 m. The tropical, xeric, savannoid, “African” south-facing slope (AS = SFS) abuts the forested “European” north-facing slope (ES = NFS). The AS receives 200–800% higher solar radiation than the ES. The ES represents the south European forested maquis. The AS and ES exhibit drought and shade stress, respectively. Major adaptations on the AS are because of solar radiation, heat, and drought, whereas those on the ES relate to light stress and photosynthesis. Preliminary evidence suggests the extinction of some European species on the ES and AS. In Drosophila, a 10-fold higher migration was recorded in 2003 from the AS to ES. I advance some predictions that could be followed in diverse species in EC. The EC microclimatic model is optimal to track global warming at a microscale across life from viruses and bacteria to mammals in Israel, and in additional ECs across the planet. PMID:22308456

Investigating added value of regional climate modeling in North American winter storm track simulations

NASA Astrophysics Data System (ADS)

Poan, E. D.; Gachon, P.; Laprise, R.; Aider, R.; Dueymes, G.

2018-03-01

Extratropical Cyclone (EC) characteristics depend on a combination of large-scale factors and regional processes. However, the latter are considered to be poorly represented in global climate models (GCMs), partly because their resolution is too coarse. This paper describes a framework using possibilities given by regional climate models (RCMs) to gain insight into storm activity during winter over North America (NA). Recent past climate period (1981-2005) is considered to assess EC activity over NA using the NCEP regional reanalysis (NARR) as a reference, along with the European reanalysis ERA-Interim (ERAI) and two CMIP5 GCMs used to drive the Canadian Regional Climate Model—version 5 (CRCM5) and the corresponding regional-scale simulations. While ERAI and GCM simulations show basic agreement with NARR in terms of climatological storm track patterns, detailed bias analyses show that, on the one hand, ERAI presents statistically significant positive biases in terms of EC genesis and therefore occurrence while capturing their intensity fairly well. On the other hand, GCMs present large negative intensity biases in the overall NA domain and particularly over NA eastern coast. In addition, storm occurrence over the northwestern topographic regions is highly overestimated. When the CRCM5 is driven by ERAI, no significant skill deterioration arises and, more importantly, all storm characteristics near areas with marked relief and over regions with large water masses are significantly improved with respect to ERAI. Conversely, in GCM-driven simulations, the added value contributed by CRCM5 is less prominent and systematic, except over western NA areas with high topography and over the Western Atlantic coastlines where the most frequent and intense ECs are located. Despite this significant added-value on seasonal-mean characteristics, a caveat is raised on the RCM ability to handle storm temporal `seriality', as a measure of their temporal variability at a given location. In fact, the driving models induce some significant footprints on the RCM skill to reproduce the intra-seasonal pattern of storm activity.

Value of eddy-covariance data for individual-based, forest gap models

NASA Astrophysics Data System (ADS)

Roedig, Edna; Cuntz, Matthias; Huth, Andreas

2014-05-01

Individual-based forest gap models simulate tree growth and carbon fluxes on large time scales. They are a well established tool to predict forest dynamics and successions. However, the effect of climatic variables on processes of such individual-based models is uncertain (e.g. the effect of temperature or soil moisture on the gross primary production (GPP)). Commonly, functional relationships and parameter values that describe the effect of climate variables on the model processes are gathered from various vegetation models of different spatial scales. Though, their accuracies and parameter values have not been validated for the specific model scales of individual-based forest gap models. In this study, we address this uncertainty by linking Eddy-covariance (EC) data and a forest gap model. The forest gap model FORMIND is applied on the Norwegian spruce monoculture forest at Wetzstein in Thuringia, Germany for the years 2003-2008. The original parameterizations of climatic functions are adapted according to the EC-data. The time step of the model is reduced to one day in order to adapt to the high resolution EC-data. The FORMIND model uses functional relationships on an individual level, whereas the EC-method measures eco-physiological responses at the ecosystem level. However, we assume that in homogeneous stands as in our study, functional relationships for both methods are comparable. The model is then validated at the spruce forest Waldstein, Germany. Results show that the functional relationships used in the model, are similar to those observed with the EC-method. The temperature reduction curve is well reflected in the EC-data, though parameter values differ from the originally expected values. For example at the freezing point, the observed GPP is 30% higher than predicted by the forest gap model. The response of observed GPP to soil moisture shows that the permanent wilting point is 7 vol-% lower than the value derived from the literature. The light response curve, integrated over the canopy and the forest stand, is underestimated compared to the measured data. The EC-method measures a yearly carbon balance of 13 mol(CO2)m-2 for the Wetzstein site. The model with the original parameterization overestimates the yearly carbon balance by nearly 5 mol(CO2)m-2 while the model with an EC-based parameterization fits the measured data very well. The parameter values derived from EC-data are applied on the spruce forest Waldstein and clearly improve estimates of the carbon balance.

Encoding instructions and stimulus presentation in local environmental context-dependent memory studies.

PubMed

Markopoulos, G; Rutherford, A; Cairns, C; Green, J

2010-08-01

Murnane and Phelps (1993) recommend word pair presentations in local environmental context (EC) studies to prevent associations being formed between successively presented items and their ECs and a consequent reduction in the EC effect. Two experiments were conducted to assess the veracity of this assumption. In Experiment 1, participants memorised single words or word pairs, or categorised them as natural or man made. Their free recall protocols were examined to assess any associations established between successively presented items. Fewest associations were observed when the item-specific encoding task (i.e., natural or man made categorisation of word referents) was applied to single words. These findings were examined further in Experiment 2, where the influence of encoding instructions and stimulus presentation on local EC dependent recognition memory was examined. Consistent with recognition dual-process signal detection model predictions and findings (e.g., Macken, 2002; Parks & Yonelinas, 2008), recollection sensitivity, but not familiarity sensitivity, was found to be local EC dependent. However, local EC dependent recognition was observed only after item-specific encoding instructions, irrespective of stimulus presentation. These findings and the existing literature suggest that the use of single word presentations and item-specific encoding enhances local EC dependent recognition.

Interplay between mast cells, enterochromaffin cells, and sensory signaling in the aging human bowel.

PubMed

Yu, Y; Daly, D M; Adam, I J; Kitsanta, P; Hill, C J; Wild, J; Shorthouse, A; Grundy, D; Jiang, W

2016-10-01

Advanced age is associated with a reduction in clinical visceral pain perception. However, the underlying mechanisms remain largely unknown. Previous studies have suggested that an abnormal interplay between mast cells, enterochromaffin (EC) cells, and afferent nerves contribute to nociception in gastrointestinal disorders. The aim of this study was to investigate how aging affects afferent sensitivity and neuro-immune association in the human bowel. Mechanical and chemical sensitivity of human bowel afferents were examined by ex vivo afferent nerve recordings. Age-related changes in the density of mast cells, EC cells, sensory nerve terminals, and mast cell-nerve micro-anatomical association were investigated by histological and immune staining. Human afferents could be broadly classified into subpopulations displaying mechanical and chemical sensitivity, adaptation, chemo-sensitization, and recruitment. Interestingly human bowel afferent nerve sensitivity was attenuated with age. The density of substance P-immunoreactive (SP-IR) nerve varicosities was also reduced with age. In contrast, the density of ileal and colonic mucosal mast cells was increased with age, as was ileal EC cell number. An increased proportion of mast cells was found in close apposition to SP-IR nerves. Afferent sensitivity in human bowel was reduced with advancing age. Augmentation of mast cells and EC cell numbers and the mast cell-nerve association suggest a compensatory mechanism for sensory neurodegeneration. © 2016 The Authors. Neurogastroenterology & Motility Published by John Wiley & Sons Ltd.

The local lymph node assay and the assessment of relative potency: status of validation.

PubMed

Basketter, David A; Gerberick, Frank; Kimber, Ian

2007-08-01

For the prediction of skin sensitization potential, the local lymph node assay (LLNA) is a fully validated alternative to guinea-pig tests. More recently, information from LLNA dose-response analyses has been used to assess the relative potency of skin sensitizing chemicals. These data are then deployed for risk assessment and risk management. In this commentary, the utility and validity of these relative potency measurements are reviewed. It is concluded that the LLNA does provide a valuable assessment of relative sensitizing potency in the form of the estimated concentration of a chemical required to produce a threefold stimulation of draining lymph node cell proliferation compared with concurrent controls (EC3 value) and that all reasonable validation requirements have been addressed successfully. EC3 measurements are reproducible in both intra- and interlaboratory evaluations and are stable over time. It has been shown also, by several independent groups, that EC3 values correlate closely with data on relative human skin sensitization potency. Consequently, the recommendation made here is that LLNA EC3 measurements should now be regarded as a validated method for the determination of the relative potency of skin sensitizing chemicals, a conclusion that has already been reached by a number of independent expert groups.

Quantifying sources of elemental carbon over the Guanzhong Basin of China: A consistent network of measurements and WRF-Chem modeling.

PubMed

Li, Nan; He, Qingyang; Tie, Xuexi; Cao, Junji; Liu, Suixin; Wang, Qiyuan; Li, Guohui; Huang, Rujin; Zhang, Qiang

2016-07-01

We conducted a year-long WRF-Chem (Weather Research and Forecasting Chemical) model simulation of elemental carbon (EC) aerosol and compared the modeling results to the surface EC measurements in the Guanzhong (GZ) Basin of China. The main goals of this study were to quantify the individual contributions of different EC sources to EC pollution, and to find the major cause of the EC pollution in this region. The EC measurements were simultaneously conducted at 10 urban, rural, and background sites over the GZ Basin from May 2013 to April 2014, and provided a good base against which to evaluate model simulation. The model evaluation showed that the calculated annual mean EC concentration was 5.1 μgC m(-3), which was consistent with the observed value of 5.3 μgC m(-3). Moreover, the model result also reproduced the magnitude of measured EC in all seasons (regression slope = 0.98-1.03), as well as the spatial and temporal variations (r = 0.55-0.78). We conducted several sensitivity studies to quantify the individual contributions of EC sources to EC pollution. The sensitivity simulations showed that the local and outside sources contributed about 60% and 40% to the annual mean EC concentration, respectively, implying that local sources were the major EC pollution contributors in the GZ Basin. Among the local sources, residential sources contributed the most, followed by industry and transportation sources. A further analysis suggested that a 50% reduction of industry or transportation emissions only caused a 6% decrease in the annual mean EC concentration, while a 50% reduction of residential emissions reduced the winter surface EC concentration by up to 25%. In respect to the serious air pollution problems (including EC pollution) in the GZ Basin, our findings can provide an insightful view on local air pollution control strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced electrochemical sensitivity of enzyme precipitate coating (EPC)-based glucose oxidase biosensors with increased free CNT loadings.

PubMed

Kim, Jae Hyun; Jun, Sun-Ae; Kwon, Yongchai; Ha, Su; Sang, Byong-In; Kim, Jungbae

2015-02-01

Enzymatic electrodes were fabricated by using three different immobilizations of glucose oxidase (GOx): covalent enzyme attachment (CA), enzyme coating (EC), and enzyme precipitate coating (EPC), here referred to as CA-E, EC-E, and EPC-E, respectively. When additional carbon nanotubes (CNTs) were introduced from 0 to 75wt% for the EPC-E design, its initial biosensor sensitivity was improved from 2.40×10(-3) to 16.26×10(-3) A∙M(-1)∙cm(-2), while its electron charge transfer rate constant was increased from 0.33 to 1.47s(-1). When a fixed ratio of CNTs was added for three different electrode systems, EPC-E showed the best glucose sensitivity and long-term thermal stability. For example, when 75wt% of additional CNTs was added, the initial sensitivity of EPC-E was 16.26×10(-3) A∙M(-1)∙cm(-2), while those of EC-E and CA-E were only 6.42×10(-3) and 1.18×10(-3) A∙M(-1)∙cm(-2), respectively. Furthermore, EPC-E retained 63% of its initial sensitivity after thermal treatment at 40°C over 41days, while EC-E and CA-E showed only 12% and 1% of initial sensitivities, respectively. Consequently, the EPC approach with additional CNTs achieved both high sensitivity and long-term stability, which are required for continuous and accurate glucose monitoring. Copyright © 2014 Elsevier B.V. All rights reserved.

The unicellular fungal tool RhoTox for risk assessments in groundwater systems.

PubMed

Lategan, Maria Josie; Klare, William; Kidd, Sarah; Hose, Grant C; Nevalainen, Helena

2016-10-01

The recent inclusion of yeasts in environmental monitoring recognizes their ecological significance and sensitivity to toxicants. Here we present a robust and simple two-step toxicity assay and demonstrate the sensitivity of an ubiquitous groundwater yeast, Rhodotorula minuta, to a range of metals and metalloids. The test species was sensitive to copper with a 24h EC50 of 35µg Cu/L, followed in order of decreasing sensitivity by zinc, chromium (VI) and arsenic (EC50 4.40mg As (III)/L). The strain demonstrated an unexpected tolerance to chromium (VI), having an EC50 value (3.45mg Cr (VI)/L) similar to that of arsenic. The inclusion of a unicellular, microbial test-species into the suite of existing multicellular test species for toxicity evaluation is a key step towards strengthening the assessment of risk for groundwater ecosystems. Copyright © 2016 Elsevier Inc. All rights reserved.

The BCL2 antagonist of cell death pathway influences endometrial cancer cell sensitivity to cisplatin.

PubMed

Chon, Hye Sook; Marchion, Douglas C; Xiong, Yin; Chen, Ning; Bicaku, Elona; Stickles, Xiaomang Ba; Bou Zgheib, Nadim; Judson, Patricia L; Hakam, Ardeshir; Gonzalez-Bosquet, Jesus; Wenham, Robert M; Apte, Sachin M; Lancaster, Johnathan M

2012-01-01

To identify pathways that influence endometrial cancer (EC) cell sensitivity to cisplatin and to characterize the BCL2 antagonist of cell death (BAD) pathway as a therapeutic target to increase cisplatin sensitivity. Eight EC cell lines (Ishikawa, MFE296, RL 95-2, AN3CA, KLE, MFE280, MFE319, HEC-1-A) were subjected to Affymetrix Human U133A GeneChip expression analysis of approximately 22,000 probe sets. In parallel, endometrial cell line sensitivity to cisplatin was quantified by MTS assay, and IC(50) values were calculated. Pearson's correlation test was used to identify genes associated with response to cisplatin. Genes associated with cisplatin responsiveness were subjected to pathway analysis. The BAD pathway was identified and subjected to targeted modulation, and the effect on cisplatin sensitivity was evaluated. Pearson's correlation analysis identified 1443 genes associated with cisplatin resistance (P<0.05), which included representation of the BAD-apoptosis pathway. Small interfering RNA (siRNA) knockdown of BAD pathway protein phosphatase PP2C expression was associated with increased phosphorylated BAD (serine-155) levels and a parallel increase in cisplatin resistance in Ishikawa (P=0.004) and HEC-1-A (P=0.02) cell lines. In contrast, siRNA knockdown of protein kinase A expression increased cisplatin sensitivity in the Ishikawa (P=0.02) cell line. The BAD pathway influences EC cell sensitivity to cisplatin, likely via modulation of the phosphorylation status of the BAD protein. The BAD pathway represents an appealing therapeutic target to increase EC cell sensitivity to cisplatin. Copyright © 2011 Elsevier Inc. All rights reserved.

Polymerase ε (POLE) ultra-mutation in uterine tumors correlates with T lymphocyte infiltration and increased resistance to platinum-based chemotherapy in vitro

PubMed Central

Bellone, Stefania; Eliana, Bignotti; Lonardi, Silvia; Ferrari, Francesca; Centritto, Floriana; Masserdotti, Alice; Pettinella, Francesca; Black, Jonathan; Menderes, Gulden; Altwerger, Gary; Hui, Pei; Lopez, Salvatore; de Haydu, Christopher; Bonazzoli, Elena; Predolini, Federica; Zammataro, Luca; Cocco, Emiliano; Ferrari, Federico; Ravaggi, Antonella; Romani, Chiara; Facchettie, Fabio; Sartori, Enrico; Odicino, Franco E.; Silasi, Dan-Arin; Litkouhi, Babak; Ratner, Elena; Azodi, Masoud; Schwartz, Peter E.; Santin, Alessandro D.

2016-01-01

Objective Up to 12 % of all endometrial-carcinomas (EC) harbor DNA-polymerase-ε-(POLE) mutations. It is currently unknown whether the favorable prognosis of POLE-mutated EC is derived from their low metastatic capability, extraordinary number of somatic mutations thus imparting immunogenicity, or a high sensitivity to chemotherapy. Methods Polymerase-chain-reaction-amplification and Sanger-sequencing were used to test for POLE exonuclease-domain-mutations (exons 9–14) 131 EC. Infiltration of CD4+ and CD8+ T-lymphocytes (TIL) and PD-1-expression in POLE-mutated vs POLE wild-type EC was studied by immunohistochemistry (IHC) and the correlations between survival and molecular features were investigated. Finally, primary POLE-mutated and POLE-wild-type EC cell lines were established and compared in-vitro for their sensitivity to chemotherapy. Results Eleven POLE-mutated EC (8.5%) were identified. POLE-mutated tumors were associated with improved progression-free-survival (P<0.05) and displayed increased numbers of CD4+ (44.5 vs 21.8; P = .001) and CD8+ (32.8 vs 13.5; P < .001) TILs when compared to wild-type POLE EC. PD-1 receptor was overexpressed in TILs from POLE-mutated vs wild-type-tumors (81% vs 28%; P < .001). Primary POLE tumor cell lines were significantly more resistant to platinum-chemotherapy in-vitro when compared to POLE-wild-type tumors (P < 0.004). Conclusions POLE ultra-mutated EC are heavily infiltrated with CD4+/CD8+ TIL, overexpress PD-1 immune-check-point (i.e., features consistent with chronic antigen-exposure), and have a better prognosis when compared to other molecular subtypes of EC patients. POLE-mutated tumor-cell lines are resistant to platinum-chemotherapy in-vitro suggesting that the better prognosis of POLE-patients is not secondary to a higher sensitivity to chemotherapy but likely linked to enhanced immunogenicity. PMID:27894751

Improved detection of Burkholderia pseudomallei from non-blood clinical specimens using enrichment culture and PCR: narrowing diagnostic gap in resource-constrained settings.

PubMed

Tellapragada, Chaitanya; Shaw, Tushar; D'Souza, Annet; Eshwara, Vandana Kalwaje; Mukhopadhyay, Chiranjay

2017-07-01

To evaluate the diagnostic utility of enrichment culture and PCR for improved case detection rates of non-bacteraemic form of melioidosis in limited resource settings. Clinical specimens (n = 525) obtained from patients presenting at a tertiary care hospital of South India with clinical symptoms suggestive of community-acquired pneumonia, lower respiratory tract infections, superficial or internal abscesses, chronic skin ulcers and bone or joint infections were tested for the presence of Burkholderia pseudomallei using conventional culture (CC), enrichment culture (EC) and PCR. Sensitivity, specificity, positive and negative predictive values of CC and PCR were initially deduced using EC as the gold standard method. Further, diagnostic accuracies of all the three methods were analysed using Bayesian latent class modelling (BLCM). Detection rates of B. pseudomallei using CC, EC and PCR were 3.8%, 5.3% and 6%, respectively. Diagnostic sensitivities and specificities of CC and PCR were 71.4, 98.4% and 100 and 99.4%, respectively in comparison with EC as the gold standard test. With Bayesian latent class modelling, EC and PCR demonstrated sensitivities of 98.7 and 99.3%, respectively, while CC showed a sensitivity of 70.3% for detection of B. pseudomallei. An increase of 1.6% (95% CI: 1.08-4.32%) in the case detection rate of melioidosis was observed in the study population when EC and/or PCR were used in adjunct to the conventional culture technique. Our study findings underscore the diagnostic superiority of enrichment culture and/or PCR over conventional microbiological culture for improved case detection of melioidosis from non-blood clinical specimens. © 2017 John Wiley & Sons Ltd.

Urban impacts on regional carbonaceous aerosols: case study in central Texas.

PubMed

Barrett, Tate E; Sheesley, Rebecca J

2014-08-01

Rural and background sites provide valuable information on the concentration and optical properties of organic, elemental, and water-soluble organic carbon (OC, EC, and WSOC), which are relevant for understanding the climate forcing potential of regional atmospheric aerosols. To quantify climate- and air quality-relevant characteristics of carbonaceous aerosol in the central United States, a regional background site in central Texas was chosen for long-term measurement. Back trajectory (BT) analysis, ambient OC, EC, and WSOC concentrations and absorption parameters are reported for the first 15 months of a long-term campaign (May 2011-August 2012). BT analysis indicates consistent north-south airflow connecting central Texas to the Central Plains. Central Texas aerosols exhibited seasonal trends with increased fine particulate matter (< 2.5 microm aerodynamic diameter, PM2.5) and OC during the summer (PM2.5 = 10.9 microg m(-3) and OC = 3.0 microg m(-3)) and elevated EC during the winter (0.22 microg m(-3)). When compared to measurements in Dallas and Houston, TX, central Texas OC appears to have mixed urban and rural sources. However central Texas EC appears to be dominated by transport of urban emissions. WSOC averaged 63% of the annual OC, with little seasonal variability in this ratio. To monitor brown carbon (BrC), absorption was measured for the aqueous WSOC extracts. Light absorption coefficients for EC and BrC were highest during summer (EC MAC = 11 m2 g(-1) and BRC MAE365 = 0.15 m2 g(-1)). Results from optical analysis indicate that regional aerosol absorption is mostly due to EC with summertime peaks in BrC attenuation. This study represents the first reported values of WSOC absorption, MAE365, for the central United States. Implications: Background concentration and absorption measurements are essential in determining regional potential radiative forcing due to atmospheric aerosols. Back trajectory, chemical, and optical analysis of PM2.5 was used to determine climatic and air quality implications of urban outflow to a regional receptor site, representative of the central United States. Results indicate that central Texas organic carbon has mixed urban and rural sources, while elemental carbon is controlled by the transport of urban emissions. Analysis of aerosol absorption showed black carbon as the dominant absorber, with less brown carbon absorption than regional studies in California and the southeastern United States.

An optimized design to reduce eddy current sensitivity in velocity-selective arterial spin labeling using symmetric BIR-8 pulses.

PubMed

Guo, Jia; Meakin, James A; Jezzard, Peter; Wong, Eric C

2015-03-01

Velocity-selective arterial spin labeling (VSASL) tags arterial blood on a velocity-selective (VS) basis and eliminates the tagging/imaging gap and associated transit delay sensitivity observed in other ASL tagging methods. However, the flow-weighting gradient pulses in VS tag preparation can generate eddy currents (ECs), which may erroneously tag the static tissue and create artificial perfusion signal, compromising the accuracy of perfusion quantification. A novel VS preparation design is presented using an eight-segment B1 insensitive rotation with symmetric radio frequency and gradient layouts (sym-BIR-8), combined with delays after gradient pulses to optimally reduce ECs of a wide range of time constants while maintaining B0 and B1 insensitivity. Bloch simulation, phantom, and in vivo experiments were carried out to determine robustness of the new and existing pulse designs to ECs, B0 , and B1 inhomogeneity. VSASL with reduced EC sensitivity across a wide range of EC time constants was achieved with the proposed sym-BIR-8 design, and the accuracy of cerebral blood flow measurement was improved. The sym-BIR-8 design performed the most robustly among the existing VS tagging designs, and should benefit studies using VS preparation with improved accuracy and reliability. © 2014 Wiley Periodicals, Inc.

Radiocarbon-based Source Apportionment of Organic, Elemental and Water-soluble Organic Carbon Aerosols and the Light Absorption of Water-soluble Organic Carbon Aerosols in the East Asia High-intensity Winter Campaigns in 2014

NASA Astrophysics Data System (ADS)

Fang, W.; Andersson, A.; Zheng, M.; Lee, M.; Kim, S. W.; Du, K.; Gustafsson, O.

2016-12-01

Improved understanding of anthropogenic aerosol effects on atmospheric chemistry and climate as well as efficient mitigation actions are hampered by the limited comprehension of the relative contributions of different sources of carbonaceous aerosols and of their subsequent atmospheric processing. Here, we present dual carbon isotope constrained source apportionment and optical properties of carbonaceous aerosols simultaneously both at urban and rural receptor sites, includes North China Plain (NCP, Beijing and Tianjin), Yangtze River Delta (YRD, Shanghai, Zhejiang), and Jeju Island (Korea Climate Observatory at Gosan) during January 2014 field campaigns. The radiocarbon (Δ14C) data show that fossil combustions contribute equally ˜80 ± 5% to elemental carbon (EC) aerosol in Beijing, Tianjin, and Shanghai, and 66 ± 9% to Gosan-EC aerosol, while the specific sources of the dominant fossil fuel component were dramatically different among these sites. The mean fraction coal combustion of Beijing-EC, Tianjin-EC, and Gosan-EC is double that of Shanghai-EC. The other large fraction (72―92%) of carbonaceous aerosol is organic carbon (OC) aerosol which contains water soluble and water insoluble organic carbon (WSOC and WISOC). OC, WISOC, and WSOC in Beijing and Gosan sites were still observed largely from fossil sources (53―75%). The more 13C-enriched signature of Gosan-WSOC (-22.8 ± 0.2‰) compared to Gosan-EC (-23.9 ± 0.4‰) and Beijing-WSOC (-23.5 ± 0.7‰) reflects that WSOC is likely more affected by atmospheric aging during long-rang transport than is EC. The high light absorption coefficients of PM2.5, PM1, and TSP were observed at Gosan during this study and was frequently reaching 20―60 Mm-1 by aethalometer and continuous light absorption photometer. The mass absorption cross section of WSOC (MAC365) for above sites is high (1.5 ± 0.8 m2/g), accounted for ˜14 ± 5% of the total direct absorbance relative to EC, which is significantly higher than the previous findings in S. Asia, N. America, and Europe.

Correlation between 96-h mortality and 24-h acetylcholinesterase inhibition in three grass shrimp larval life stages.

PubMed

Key, Peter B; Fulton, Michael H

2006-03-01

Three life stages of larval grass shrimp were tested to determine whether acetylcholinesterase (AChE) activity expressed as 24-h sublethal effect endpoints (EC20 and EC50) could be used to predict 96-h mortality (lowest observable effect concentration (LOEC) and LC50) for shrimp exposed to three organophosphate insecticides. With regard to mortality, newly hatched larvae and 18-day-old larvae were the most sensitive in the malathion and azinphosmethyl exposures. In the chlorpyrifos exposures, newly hatched larvae and postlarvae were the most sensitive life stages. Results of the 24-h AChE inhibition tests showed that newly hatched larvae were generally more sensitive in the three organophosphate exposures. A regression analysis of the EC50's and LC50's yielded the strongest correlation with R2=0.987 (correlation coefficient=0.994 and 95% confidence intervals 0.969-0.999). The LOEC/EC20 relationship yielded R2=0.962. For these grass shrimp life stages and pesticides, sublethal effect endpoints could be used as a predictor of 96-h mortality.

Acute toxicity of endosulfan 35EC to two freshwater bivalve molluscs from Godavari river at Maharashtra State, India.

PubMed

Mane, U H; Muley, D V

1984-11-01

Static bioassay tests were conducted using commercial grade endosulfan 35EC to study its toxicity during different seasons to two species of Lamellidens from the Godavari river at Paithan (Maharashtra State). Acute toxicity studies for 96 h showed that both species of Lamellidens were more sensitive to endosulfan 35EC in summer, at times of high temperature, pH and total carbonate content of the water used, than in monsoon and winter. LC0 and LC50 values were determined for L. corrianus and L. marginalis, during summer, monsoon and winter. Statistical analyses showed that both species were more sensitive during summer (P less than 0.001) than in monsoon and winter and that L. marginalis was more sensitive to endosulfan 35EC than L. corrianus in summer (P less than 0.001). Behavioural changes and mortality of the bivalves were dose-related. Regression equations and 95% confidence limits for each species were established in different studies. The results are discussed in the light of possible effects of endosulfan on these species of bivalve molluscs.

Greenland ice sheet beyond 2100: Simulating its evolution and influence using the coupled climate-ice sheet model EC-Earth - PISM

NASA Astrophysics Data System (ADS)

Yang, S.; Christensen, J. H.; Madsen, M. S.; Ringgaard, I. M.; Petersen, R. A.; Langen, P. P.

2017-12-01

Greenland ice sheet (GrIS) is observed undergoing a rapid change in the recent decades, with an increasing area of surface melting and ablation and a speeding mass loss. Predicting the GrIS changes and their climate consequences relies on the understanding of the interaction of the GrIS with the climate system on both global and local scales, and requires climate model systems incorporating with an explicit and physically consistent ice sheet module. In this work we study the GrIS evolution and its interaction with the climate system using a fully coupled global climate model with a dynamical ice sheet model for the GrIS. The coupled model system, EC-EARTH - PISM, consisting of the atmosphere-ocean-sea ice model system EC-EARTH, and the Parallel Ice Sheet Model (PISM), has been employed for a 1400-year simulation forced by CMIP5 historical forcing from 1850 to 2005 and continued along an extended RCP8.5 scenario with the forcing peaking at 2200 and stabilized hereafter. The simulation reveals that, following the anthropogenic forcing increase, the global mean surface temperature rapidly rises about 10 °C in the 21st and 22nd century. After the forcing stops increasing after 2200, the temperature change slows down and eventually stabilizes at about 12.5 °C above the preindustrial level. In response to the climate warming, the GrIS starts losing mass slowly in the 21st century, but the ice retreat accelerates substantially after 2100 and ice mass loss continues hereafter at a constant rate of approximately 0.5 m sea level rise equivalence per 100 years, even as the warming rate gradually levels off. Ultimately the volume and extent of GrIS reduce to less than half of its preindustrial value. To understand the interaction of GrIS with the climate system, the characteristics of atmospheric and oceanic circulation in the warm climate are analyzed. The circulation patterns associated with the negative surface mass balance that leads to GrIS retreat are investigated. The impact of the simulated surface warming on the ice flow and ice dynamics is explored.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons, Brian; Cochran, Jaquelin; Watson, Andrea

As a recognized leader in efforts to mitigate global climate change, the Government of Mexico (GOM) works proactively to reduce emissions, demonstrating strong political will and capacity to comprehensively address climate change. Since 2010, the U.S. government (USG) has supported these efforts by partnering with Mexico under the Enhancing Capacity for Low Emission Development Strategies (EC-LEDS) program. Through the program, the USG has partnered with Mexico’s Ministry of Energy (SENER), as well as other government agencies, to support GOM in reaching its clean energy and climate change goals. Specifically, the EC-LEDS program is supporting GOM’s clean energy goal of generatingmore » 35% of its electricity from renewable energy (RE) by 2024. EC-LEDS, through the U.S. Agency for International Development (USAID) and the U.S Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL), has been collaborating with SENER and GOM interagency working group—the Consejo Consultivo para las Energías Renovables (Consultative Council on Renewable Energy)—to create a grid integration roadmap for variable RE. 1 A key objective in creating a grid integration roadmap is assessing likely impacts of wind and solar energy on the power system and modifying planning and operations accordingly. This paper applies best practices in conducting a grid integration study to the Mexican context.« less

Geochemical responses of forested catchments to bark beetle infestation: Evidence from high frequency in-stream electrical conductivity monitoring

NASA Astrophysics Data System (ADS)

Su, Ye; Langhammer, Jakub; Jarsjö, Jerker

2017-07-01

Under the present conditions of climate warming, there has been an increased frequency of bark beetle-induced tree mortality in Asia, Europe, and North America. This study analyzed seven years of high frequency monitoring of in-stream electrical conductivity (EC), hydro-climatic conditions, and vegetation dynamics in four experimental catchments located in headwaters of the Sumava Mountains, Central Europe. The aim was to determine the effects of insect-induced forest disturbance on in-stream EC at multiple timescales, including annual and seasonal average conditions, daily variability, and responses to individual rainfall events. Results showed increased annual average in-stream EC values in the bark beetle-infected catchments, with particularly elevated EC values during baseflow conditions. This is likely caused by the cumulative loading of soil water and groundwater that discharge excess amounts of substances such as nitrogen and carbon, which are released via the decomposition of the needles, branches, and trunks of dead trees, into streams. Furthermore, we concluded that infestation-induced changes in event-scale dynamics may be largely responsible for the observed shifts in annual average conditions. For example, systematic EC differences between baseflow conditions and event flow conditions in relatively undisturbed catchments were essentially eliminated in catchments that were highly disturbed by bark beetles. These changes developed relatively rapidly after infestation and have long-lasting (decadal-scale) effects, implying that cumulative impacts of increasingly frequent bark beetle outbreaks may contribute to alterations of the hydrogeochemical conditions in more vulnerable mountain regions.

Medium-range reference evapotranspiration forecasts for the contiguous United States based on multi-model numerical weather predictions

NASA Astrophysics Data System (ADS)

Medina, Hanoi; Tian, Di; Srivastava, Puneet; Pelosi, Anna; Chirico, Giovanni B.

2018-07-01

Reference evapotranspiration (ET0) plays a fundamental role in agronomic, forestry, and water resources management. Estimating and forecasting ET0 have long been recognized as a major challenge for researchers and practitioners in these communities. This work explored the potential of multiple leading numerical weather predictions (NWPs) for estimating and forecasting summer ET0 at 101 U.S. Regional Climate Reference Network stations over nine climate regions across the contiguous United States (CONUS). Three leading global NWP model forecasts from THORPEX Interactive Grand Global Ensemble (TIGGE) dataset were used in this study, including the single model ensemble forecasts from the European Centre for Medium-Range Weather Forecasts (EC), the National Centers for Environmental Prediction Global Forecast System (NCEP), and the United Kingdom Meteorological Office forecasts (MO), as well as multi-model ensemble forecasts from the combinations of these NWP models. A regression calibration was employed to bias correct the ET0 forecasts. Impact of individual forecast variables on ET0 forecasts were also evaluated. The results showed that the EC forecasts provided the least error and highest skill and reliability, followed by the MO and NCEP forecasts. The multi-model ensembles constructed from the combination of EC and MO forecasts provided slightly better performance than the single model EC forecasts. The regression process greatly improved ET0 forecast performances, particularly for the regions involving stations near the coast, or with a complex orography. The performance of EC forecasts was only slightly influenced by the size of the ensemble members, particularly at short lead times. Even with less ensemble members, EC still performed better than the other two NWPs. Errors in the radiation forecasts, followed by those in the wind, had the most detrimental effects on the ET0 forecast performances.

Elevation-dependent warming in global climate model simulations at high spatial resolution

NASA Astrophysics Data System (ADS)

Palazzi, Elisa; Mortarini, Luca; Terzago, Silvia; von Hardenberg, Jost

2018-06-01

The enhancement of warming rates with elevation, so-called elevation-dependent warming (EDW), is one of the regional, still not completely understood, expressions of global warming. Sentinels of climate and environmental changes, mountains have experienced more rapid and intense warming trends in the recent decades, leading to serious impacts on mountain ecosystems and downstream. In this paper we use a state-of-the-art Global Climate Model (EC-Earth) to investigate the impact of model spatial resolution on the representation of this phenomenon and to highlight possible differences in EDW and its causes in different mountain regions of the Northern Hemisphere. To this end we use EC-Earth climate simulations at five different spatial resolutions, from ˜ 125 to ˜ 16 km, to explore the existence and the driving mechanisms of EDW in the Colorado Rocky Mountains, the Greater Alpine Region and the Tibetan Plateau-Himalayas. Our results show that the more frequent EDW drivers in all regions and seasons are the changes in albedo and in downward thermal radiation and this is reflected in both daytime and nighttime warming. In the Tibetan Plateau-Himalayas and in the Greater Alpine Region, an additional driver is the change in specific humidity. We also find that, while generally the model shows no clear resolution dependence in its ability to simulate the existence of EDW in the different regions, specific EDW characteristics such as its intensity and the relative role of different driving mechanisms may be different in simulations performed at different spatial resolutions. Moreover, we find that the role of internal climate variability can be significant in modulating the EDW signal, as suggested by the spread found in the multi-member ensemble of the EC-Earth experiments which we use.

Stretchable and Photocatalytically Renewable Electrochemical Sensor Based on Sandwich Nanonetworks for Real-Time Monitoring of Cells.

PubMed

Wang, Ya-Wen; Liu, Yan-Ling; Xu, Jia-Quan; Qin, Yu; Huang, Wei-Hua

2018-05-15

Stretchable electrochemical (EC) sensors have broad prospects in real-time monitoring of living cells and tissues owing to their excellent elasticity and deformability. However, the redox reaction products and cell secretions are easily adsorbed on the electrode, resulting in sensor fouling and passivation. Herein, we developed a stretchable and photocatalytically renewable EC sensor based on Au nanotubes (NTs) and TiO 2 nanowires (NWs) sandwich nanonetworks. The external Au NTs are used for EC sensing, and internal TiO 2 NWs provide photocatalytic performance to degrade contaminants, which endows the sensor with excellent EC performance, high photocatalytic activity, and favorable mechanical tensile property. This allows highly sensitive recycling monitoring of NO released from endothelial cells and 5-HT released from mast cells under their stretching states in real time, therefore providing a promising tool to unravel elastic and mechanically sensitive cells, tissues, and organs.

The future of the Devon Ice cap: results from climate and ice dynamics modelling

NASA Astrophysics Data System (ADS)

Mottram, Ruth; Rodehacke, Christian; Boberg, Fredrik

2017-04-01

The Devon Ice Cap is an example of a relatively well monitored small ice cap in the Canadian Arctic. Close to Greenland, it shows a similar surface mass balance signal to glaciers in western Greenland. Here we use high resolution (5km) simulations from HIRHAM5 to drive the PISM glacier model in order to model the present day and future prospects of this small Arctic ice cap. Observational data from the Devon Ice Cap in Arctic Canada is used to evaluate the surface mass balance (SMB) data output from the HIRHAM5 model for simulations forced with the ERA-Interim climate reanalysis data and the historical emissions scenario run by the EC-Earth global climate model. The RCP8.5 scenario simulated by EC-Earth is also downscaled by HIRHAM5 and this output is used to force the PISM model to simulate the likely future evolution of the Devon Ice Cap under a warming climate. We find that the Devon Ice Cap is likely to continue its present day retreat, though in the future increased precipitation partly offsets the enhanced melt rates caused by climate change.

Climate Symposium 2014: Findings and Recommendations

DOE PAGES

Asrar, Ghassem; Bony, Sandrine; Boucher, Olivier; ...

2015-10-05

Here, the Climate Symposium 2014, organized by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the World Climate Research Programme (WCRP), with support from the European Commission (EC), European Space Agency (ESA), and other agencies, took place in Darmstadt, Germany, from 13 to 17 October 2014. Around 500 participants from 49 countries attended the event and represented over 200 organizations. Another 500 individuals participated remotely via “live streaming.”

Screening for unicellular algae as possible bioassay organisms for monitoring marine water samples.

PubMed

Millán de Kuhn, Rosmary; Streb, Christine; Breiter, Roman; Richter, Peter; Neesse, Thomas; Häder, Donat-Peter

2006-08-01

ECOTOX is an automatic early warning system to monitor potential pollution of freshwater, municipal or industrial waste waters or aquatic ecosystems. It is based on a real time image analysis of the motility and orientation parameters of the unicellular, photosynthetic flagellate Euglena gracilis. In order to widen the use of the device to marine habitats and saline waters nine marine flagellates were evaluated as putative bioassay organisms, viz. Dunaliella salina, Dunaliella viridis, Dunaliella bardawil, Prorocentrum minimum Kattegat, P. minimum Lissabon, Tetraselmis suecica, Heterocapsa triquetra, Gyrodinium dorsum and Cryptomonas maculata. Because of their slow growth the last three strains were excluded from further evaluation. Selection criteria were ease of culture, density of cell suspension, stability of motility and gravitactic orientation. The sensitivity toward toxins was tested using copper(II) ions. The instrument allows the user to automatically determine effect-concentration (EC) curves from which the EC(50) values can be calculated. For the interpretation of the EC curves a sigmoid logistic model was proposed which proved to be satisfactory for all tested strains. The inhibition of the motility was considered as the most appropriate movement parameter as an endpoint. The Dunaliella species had the lowest sensitivity to copper with EC(50) values of 220, 198 and 176 mg/L for D. salina, D. bardawil and D. viridis, respectively, followed by T. suecica with an EC(50) value of 40 mg/L. The Prorocentrum species were found to be the most sensitive with an EC(50) value of 13.5 mg/L for P. minimum Lissabon and 7.5 mg/L for P. minimum Kattegat.

Emotional Climate and High Quality Learning Experiences in Science Teacher Education

ERIC Educational Resources Information Center

Bellocchi, Alberto; Ritchie, Stephen M.; Tobin, Kenneth; King, Donna; Sandhu, Maryam; Henderson, Senka

2014-01-01

The role of emotion during learning encounters in science teacher education is under-researched and under-theorized. In this case study, we explore the emotional climates (ECs), that is, the collective states of emotional arousal, of a preservice secondary science education class to illuminate practice for producing and reproducing high quality…

Most robust estimate of the Transient Climate Response yet?

NASA Astrophysics Data System (ADS)

Haustein, Karsten; Venema, Victor; Schurer, Andrew

2017-04-01

Estimates of the Transient Climate Response often lack a coherent hemispheric or otherwise spatio-temporal representation. In the light of recent work that highlights the importance of inhomogeneous forcing considerations (Shindell et al 2014; Marvel et al 2015) and tas/tos-related inaccuracies (Richardson et al. 2016), here we present results from a well-tested two-box response model that takes these effects carefully into account. All external forcing data are updated based on latest emission estimates as well as recent TSI and volcanic AOD estimates. So are observed GMST data which include data for the entire year of 2016. Hence we also provide one of the first TCR estimates taking the latest El Nino into account. We demonstrate that short-term climate variability is not going to change the TCR estimate beyond very minor fluctuations. The method is therefore shown to be robust within surprisingly small uncertainty estimates. Using PMIP3 and an extended ensemble of HadCM3 simulations (Euro500; Schurer et al. 2014) GCM simulations for the pre-industrial period, we test the fast and slow response time constants that are tailored for observational data (Ripdal 2012). We also test the hemispheric response as well as the response over land and ocean separately. The TCR/ECS ratio is taken from a selected sub-set of CMIP5 simulations. The selection criteria is the best spatiotemporal match over 4 different time periods between 1860 and 2010. We will argue that this procedure should also be standard procedure to estimate ECS from observations, rather than relying on OHC estimates only. Finally, the demonstrate that PMIP3-type simulations that are initialised at least a century before 1850 (as is the standard initialisation for CMIP5-type simulations) are to be preferred. Remaining long-term radiative imbalance due to strong volcanic eruptions (e.g. Gleckler et al. 2006) tend to make CMIP5-type simulations slightly more sensitive to forcing, which leads to detectable stronger warming up until recent day.

The reliability of running economy expressed as oxygen cost and energy cost in trained distance runners.

PubMed

Shaw, Andrew J; Ingham, Stephen A; Fudge, Barry W; Folland, Jonathan P

2013-12-01

This study assessed the between-test reliability of oxygen cost (OC) and energy cost (EC) in distance runners, and contrasted it with the smallest worthwhile change (SWC) of these measures. OC and EC displayed similar levels of within-subject variation (typical error < 3.85%). However, the typical error (2.75% vs 2.74%) was greater than the SWC (1.38% vs 1.71%) for both OC and EC, respectively, indicating insufficient sensitivity to confidently detect small, but meaningful, changes in OC and EC.

Devon Ice cap's future: results from climate and ice dynamics modelling via surface mass balance modelling

NASA Astrophysics Data System (ADS)

Rodehacke, C. B.; Mottram, R.; Boberg, F.

2017-12-01

The Devon Ice Cap is an example of a relatively well monitored small ice cap in the Canadian Arctic. Close to Greenland, it shows a similar surface mass balance signal to glaciers in western Greenland. Here we various boundary conditions, ranging from ERA-Interim reanalysis data via global climate model high resolution (5km) output from the regional climate model HIRHAM5, to determine the surface mass balance of the Devon ice cap. These SMB estimates are used to drive the PISM glacier model in order to model the present day and future prospects of this small Arctic ice cap. Observational data from the Devon Ice Cap in Arctic Canada is used to evaluate the surface mass balance (SMB) data output from the HIRHAM5 model for simulations forced with the ERA-Interim climate reanalysis data and the historical emissions scenario run by the EC-Earth global climate model. The RCP8.5 scenario simulated by EC-Earth is also downscaled by HIRHAM5 and this output is used to force the PISM model to simulate the likely future evolution of the Devon Ice Cap under a warming climate. We find that the Devon Ice Cap is likely to continue its present day retreat, though in the future increased precipitation partly offsets the enhanced melt rates caused by climate change.

Multi-scale enhancement of climate prediction over land by improving the model sensitivity to vegetation variability

NASA Astrophysics Data System (ADS)

Alessandri, A.; Catalano, F.; De Felice, M.; Hurk, B. V. D.; Doblas-Reyes, F. J.; Boussetta, S.; Balsamo, G.; Miller, P. A.

2017-12-01

Here we demonstrate, for the first time, that the implementation of a realistic representation of vegetation in Earth System Models (ESMs) can significantly improve climate simulation and prediction across multiple time-scales. The effective sub-grid vegetation fractional coverage vary seasonally and at interannual time-scales in response to leaf-canopy growth, phenology and senescence. Therefore it affects biophysical parameters such as the surface resistance to evapotranspiration, albedo, roughness lenght, and soil field capacity. To adequately represent this effect in the EC-Earth ESM, we included an exponential dependence of the vegetation cover on the Leaf Area Index.By comparing two sets of simulations performed with and without the new variable fractional-coverage parameterization, spanning from centennial (20th Century) simulations and retrospective predictions to the decadal (5-years), seasonal (2-4 months) and weather (4 days) time-scales, we show for the first time a significant multi-scale enhancement of vegetation impacts in climate simulation and prediction over land. Particularly large effects at multiple time scales are shown over boreal winter middle-to-high latitudes over Canada, West US, Eastern Europe, Russia and eastern Siberia due to the implemented time-varying shadowing effect by tree-vegetation on snow surfaces. Over Northern Hemisphere boreal forest regions the improved representation of vegetation-cover consistently correct the winter warm biases, improves the climate change sensitivity, the decadal potential predictability as well as the skill of forecasts at seasonal and weather time-scales. Significant improvements of the prediction of 2m temperature and rainfall are also shown over transitional land surface hot spots. Both the potential predictability at decadal time-scale and seasonal-forecasts skill are enhanced over Sahel, North American Great Plains, Nordeste Brazil and South East Asia, mainly related to improved performance in the surface evapotranspiration.Above results are discussed in a peer-review paper just being accepted for publication on Climate Dynamics (Alessandri et al., 2017; doi:10.1007/s00382-017-3766-y).

Expression of Finger Millet EcDehydrin7 in Transgenic Tobacco Confers Tolerance to Drought Stress.

PubMed

Singh, Rajiv Kumar; Singh, Vivek Kumar; Raghavendrarao, Sanagala; Phanindra, Mullapudi Lakshmi Venkata; Venkat Raman, K; Solanke, Amolkumar U; Kumar, Polumetla Ananda; Sharma, Tilak Raj

2015-09-01

One of the critical alarming constraints for agriculture is water scarcity. In the current scenario, global warming due to climate change and unpredictable rainfall, drought is going to be a master player and possess a big threat to stagnating gene pool of staple food crops. So it is necessary to understand the mechanisms that enable the plants to cope with drought stress. In this study, effort was made to prospect the role of EcDehydrin7 protein from normalized cDNA library of drought tolerance finger millet in transgenic tobacco. Biochemical and molecular analyses of T0 transgenic plants were done for stress tolerance. Leaf disc assay, seed germination test, dehydration assay, and chlorophyll estimation showed EcDehydrin7 protein directly link to drought tolerance. Northern and qRT PCR analyses shows relatively high expression of EcDehydrin7 protein compare to wild type. T0 transgenic lines EcDehydrin7(11) and EcDehydrin7(15) shows superior expression among all lines under study. In summary, all results suggest that EcDehydrin7 protein has a remarkable role in drought tolerance and may be used for sustainable crop breeding program in other food crops.

Chronic sensitivity of white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) to cadmium, copper, lead, or zinc in laboratory water-only exposures

USGS Publications Warehouse

Wang, Ning; Ingersoll, Christopher G.; Dorman, Rebecca A.; Brumbaugh, William G.; Mebane, Christopher A.; Kunz, James L.; Hardesty, Douglas K.

2014-01-01

Chronic toxicity of cadmium, copper, lead, or zinc to white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) was evaluated in water-only exposures started with newly hatched larvae or approximately 1-mo-old juveniles. The 20% effect concentration (EC20) for cadmium from the sturgeon tests was higher than the EC20 from the trout tests, whereas the EC20 for copper, lead, or zinc for the sturgeon were lower than those EC20s for the trout. When the EC20s from the present study were included in compiled toxicity databases for all freshwater species, species mean chronic value for white sturgeon was in a relatively low percentile of the species sensitivity distribution for copper (9th percentile) and in the middle percentile for cadmium (55th percentile), zinc (40th percentile), or lead (50th percentile). However, the species mean chronic value for rainbow trout was in a high percentile for copper, lead, and zinc (∼68th–82nd percentile), but in a low percentile for cadmium (23rd percentile). The trout EC20s for each of the 4 metals and the sturgeon EC20s for cadmium or lead were above US Environmental Protection Agency chronic ambient water quality criteria (AWQC) or Washington State chronic water quality standards (WQS), whereas the sturgeon EC20s for copper or zinc were approximately equal to or below the chronic AWQC and WQS. In addition, acute 50% effect concentrations (EC50s) for copper obtained in the first 4 d of the chronic sturgeon test were below the final acute value used to derive acute AWQC and below acute WQS for copper.

EC-18, a synthetic monoacetyldiglyceride (1-palmitoyl-2-linoleoyl-3-acetylglycerol), attenuates the asthmatic response in an aluminum hydroxide/ovalbumin-induced model of asthma.

PubMed

Shin, In-Sik; Shin, Na-Rae; Jeon, Chan-Mi; Kwon, Ok-Kyoung; Sohn, Ki-Young; Lee, Tae-Suk; Kim, Jae-Wha; Ahn, Kyung-Seop; Oh, Sei-Ryang

2014-01-01

EC-18 is a synthetic monoacetyldiaglyceride that is a major constituent in antlers of Sika deer (Cervus nippon Temmenick). In this study, we evaluated the protective effects of EC-18 on Th2-type cytokines, eosinophil infiltration, and other factors in an aluminum hydroxide/ovalbumin (OVA)-induced murine asthma model. Mice were sensitized on days 0 and 14 by intraperitoneal injection of OVA with aluminum hydroxide. On days 21, 22 and 23 after the initial sensitization, the mice received an airway challenge with OVA for 1h using an ultrasonic nebulizer. EC-18 was administered to mice by oral gavage at doses of 30mg/kg and 60mg/kg once daily from day 18 to 23. Methacholine responsiveness was measured 24h after the final OVA challenge, and the bronchoalveolar lavage fluid (BALF) was collected 48h after the final OVA challenge. EC-18 significantly reduced methacholine responsiveness, T helper type 2 (Th2) cytokines, eotaxin-1, immunoglobulin (Ig) E, IgG, and the number of inflammatory cells. In addition, EC-18-treated mice exhibited the reduction in the expression of inducible nitric oxide synthase (iNOS) in lung tissue. In the histological analysis using hematoxylin-eosin stain and periodic acid-Schiff stain, EC-18 attenuated the infiltration of inflammatory cells into the airway and reduced the level of mucus production. Our results showed that EC-18 effectively suppressed the asthmatic response induced by OVA challenge. These effects were considered to be associated with iNOS suppression. In conclusion, this study suggests that EC-18 may be a therapeutic agent for allergic asthma. Copyright © 2013 Elsevier B.V. All rights reserved.

Can an endocytoscope system (ECS) predict histology in neoplastic lesions?

PubMed

Eberl, T; Jechart, G; Probst, A; Golczyk, M; Bittinger, M; Scheubel, R; Arnholdt, H; Knuechel, R; Messmann, H

2007-06-01

An endocytoscope system (ECS) has recently been developed with the possibility of super-high magnification of gastrointestinal mucosa, thus allowing in vivo imaging of living cells. The aim of the present study was to assess the potential of ECS in the prediction of histology in both normal gastrointestinal mucosa and neoplastic lesions. In total, 76 patients (57 men, 19 women; age range 37-86 years) with neoplastic lesions in the esophagus, stomach, or colon were enrolled into the study and underwent esophagogastroduodenoscopy or colonoscopy. After staining with 1% methylene blue, the mucosa was examined with the ECS probe (x 450 and x 1100 magnification), and video sequences were recorded on video disk. Biopsies from the examined areas were taken for histology and served as the gold standard. The endocytoscope video sequences were evaluated by two blinded pathologists. Finally the results were compared with those resulting from the evaluation of an experienced endoscopist who was aware of the macroscopic endoscopic pictures and the endocytoscope image results. A total of 25 patients with esophageal lesions, 28 patients with colonic lesions, and 23 patients with gastric lesions were examined. The sensitivity and specificity for the evaluation of the blinded pathologists was 81% and 100%, respectively, in the esophagus, 56% and 89% in the stomach, and 79% and 90% in the colon. If an endoscopist evaluated the endocytoscopic pictures in combination with the macroscopic endoscopic images sensitivity and specificity increased significantly. First experiences with ECS show good sensitivity rates even by blinded assessment for esophageal and colonic lesions. Sensitivity for neoplastic lesions in the stomach is lower because of gastric mucous secretion. Combining the endoscopic and cytoscopic appearance of the lesion may further enhance the diagnostic value of the method.

Sensitivity and specificity of a hand-held milk electrical conductivity meter compared to the California mastitis test for mastitis in dairy cattle.

PubMed

Fosgate, G T; Petzer, I M; Karzis, J

2013-04-01

Screening tests for mastitis can play an important role in proactive mastitis control programs. The primary objective of this study was to compare the sensitivity and specificity of milk electrical conductivity (EC) to the California mastitis test (CMT) in commercial dairy cattle in South Africa using Bayesian methods without a perfect reference test. A total of 1848 quarter milk specimens were collected from 173 cows sampled during six sequential farm visits. Of these samples, 25.8% yielded pathogenic bacterial isolates. The most frequently isolated species were coagulase negative Staphylococci (n=346), Streptococcus agalactiae (n=54), and Staphylococcus aureus (n=42). The overall cow-level prevalence of mastitis was 54% based on the Bayesian latent class (BLC) analysis. The CMT was more accurate than EC for classification of cows having somatic cell counts >200,000/mL and for isolation of a bacterial pathogen. BLC analysis also suggested an overall benefit of CMT over EC but the statistical evidence was not strong (P=0.257). The Bayesian model estimated the sensitivity and specificity of EC (measured via resistance) at a cut-point of >25 mΩ/cm to be 89.9% and 86.8%, respectively. The CMT had a sensitivity and specificity of 94.5% and 77.7%, respectively, when evaluated at the weak positive cut-point. EC was useful for identifying milk specimens harbouring pathogens but was not able to differentiate among evaluated bacterial isolates. Screening tests can be used to improve udder health as part of a proactive management plan. Copyright © 2012 Elsevier Ltd. All rights reserved.

Opiate-like electroencephalographic and behavioral effects of electroconvulsive shock in rats.

PubMed

Tortella, F C; Cowan, A; Belenky, G L; Holaday, J W

1981-12-03

Rats were studied (a) after a single transauricular electroshock (acute ECS) and (b) following 10 consecutive once-daily shocks (chronic ECS). ECS produced a generalized convulsion marked by a polyspike EEG seizure. The seizure was followed by a period of postictal depression (PID) characterized by EEG high-voltage synchrony, EMG quietening, and an associated stuporous behavior in the rat. Acute ECS produced a maximal of 33 +/- 8 (S.E.) percent above control in the EEG voltage output during postictus, with the PID lasting 2680 +/- 658 sec. Chronic ECS resulted in a significant enhancement of these acute responses. Pretreating rats with naloxone (0.3-10 mg/kg s.c.) antagonized the postictal effects of acute ECS, but not of chronic ECS. These naloxone-sensitive postictal EEG and behavioral changes appear to reflect a release of endogenous opioid peptides during ictus, a finding consistent with the hypothesis that electroshock activates opioid systems.

Soil salinity study in Northern Great Plains sodium affected soil

NASA Astrophysics Data System (ADS)

Kharel, Tulsi P.

Climate and land-use changes when combined with the marine sediments that underlay portions of the Northern Great Plains have increased the salinization and sodification risks. The objectives of this dissertation were to compare three chemical amendments (calcium chloride, sulfuric acid and gypsum) remediation strategies on water permeability and sodium (Na) transport in undisturbed soil columns and to develop a remote sensing technique to characterize salinization in South Dakota soils. Forty-eight undisturbed soil columns (30 cm x 15 cm) collected from White Lake, Redfield, and Pierpont were used to assess the chemical remediation strategies. In this study the experimental design was a completely randomized design and each treatment was replicated four times. Following the application of chemical remediation strategies, 45.2 cm of water was leached through these columns. The leachate was separated into 120- ml increments and analyzed for Na and electrical conductivity (EC). Sulfuric acid increased Na leaching, whereas gypsum and CaCl2 increased water permeability. Our results further indicate that to maintain effective water permeability, ratio between soil EC and sodium absorption ratio (SAR) should be considered. In the second study, soil samples from 0-15 cm depth in 62 x 62 m grid spacing were taken from the South Dakota Pierpont (65 ha) and Redfield (17 ha) sites. Saturated paste EC was measured on each soil sample. At each sampling points reflectance and derived indices (Landsat 5, 7, 8 images), elevation, slope and aspect (LiDAR) were extracted. Regression models based on multiple linear regression, classification and regression tree, cubist, and random forest techniques were developed and their ability to predict soil EC were compared. Results showed that: 1) Random forest method was found to be the most effective method because of its ability to capture spatially correlated variation, 2) the short wave infrared (1.5 -2.29 mum) and near infrared (0.75-0.90 mum) were very sensitive to soil salinity; 3) EC prediction model using all 3 season (spring, summer and fall) images was better on state wide validation dataset compared to individual season model. Finally, in eastern South Dakota, the model predicted that from 2008 to 2012, EC increased in 569,165 ha or 13.4% of the land seeded to corn (Zea mays L.) or soybeans (Glycine max L).

What strategy is needed for attaining the EU air quality regulations under future climate change scenarios? A sensitivity analysis over Europe

NASA Astrophysics Data System (ADS)

Jiménez-Guerrero, P.; Baró, R.; Gómez-Navarro, J. J.; Lorente-Plazas, R.; García-Valero, J. A.; Hernández, Z.; Montávez, J. P.

2012-04-01

A wide number of studies show that several areas over Europe exceed some of the air quality thresholds established in the legislation. These exceedances will become more frequent under future climate change scenarios, since the policies aimed at improving air quality in the EU directives have not accounted for the variations in the climate. Climate change alone will influence the future concentrations of atmospheric pollutants through modifications of gas-phase chemistry, transport, removal, and natural emissions. In this sense, chemistry transport models (CTMs) play a key role in assessing and understanding the emissions abatement plans through the use of sensitivity analysis strategies. These sensitivity analyses characterize the change in model output due to variations in model input parameters. Since the management strategies of air pollutant emission is one of the predominant factors for controlling urban air quality, this work assesses the impact of various emission reduction scenarios in air pollution levels over Europe under two climate change scenarios. The methodology includes the use of a climate version of the meteorological model MM5 coupled with the CHIMERE chemistry transport model. Experiments span the periods 1971-2000, as a reference, and 2071-2100, as two future enhanced greenhouse gas and aerosol scenarios (SRES A2 and B2). The atmospheric simulations have an horizontal resolution of 25 km and 23 vertical layers up to 100 hPa, and are driven by the global climate model ECHO-G . In order to represent the sensitivity of the chemistry and transport of aerosols, tropospheric ozone and other photochemical species, several hypothetical scenarios of emission control have been implemented to quantify the influence of diverse emission sources in the area, such as on-road traffic, port and industrial emissions, among others. The modeling strategy lies on a sensitivity analysis to determine the emission reduction and strategy needed in the target area in order to attain the standards and thresholds set in the European Directive 2008/50/EC. Results depict that the system is able to characterize the exceedances occurring in Europe, mainly related to the maximum 8h moving average exceeding the target value of 120 μg/m3, mainly over southern Europe. Also, compliance of the PM10 daily limit values (50 μg/m3) is not achieved over wide areas in Europe. The sensitivity analysis indicates that large reductions of precursors emissions are needed in all the scenarios examined for attaining the thresholds set in the European Directive. In most cases this abatement strategy is hard to take into practice (e.g. unrealistic percentage of emission reductions in on-road traffic, industry or harbor activity); however, ozone and particulate matter air pollution improve considerably in most of the scenarios included. Results also unveil the propagation of uncertainties from the meteorological projections into future air quality and claim for future studies aimed at deepening the knowledge about the parameterized processes, the definition of emissions and, last, reducing uncertainties.

Raising Climate Literacy of K-12 Teachers with Datastreme Earth's Climate System

NASA Astrophysics Data System (ADS)

Brey, J. A.; Geer, I.; Weinbeck, R. S.; Mills, E. W.; Nugnes, K. A.

2014-12-01

The American Meteorological Society (AMS) DataStreme Project is a free professional development program for in-service K-12 teachers, in which they gain considerable subject matter content and confidence in Earth science instruction. DataStreme Atmosphere, Ocean, and Earth's Climate System (ECS) are offered each fall and spring semester by Local Implementation Teams (LITs) across the country in coordination with a team of AMS Education Program scientists and educators who develop instructional materials, provide logistical support to the LITs, and administer the project. The 3-member LITs mentor about 8 teachers and in some instances an emergency manager, per semester through a given DataStreme course. Teachers may receive 3 tuition-free graduate credits through State University of New York's The College at Brockport upon completion of each DataStreme course. DataStreme is in close alignment with A Framework for K-12 Science Education and the Next Generation Science Standards (NGSS). Investigating the scientific basis of the workings of Earth's atmosphere, ocean, and climate system follows the cross-cutting theme of the Framework and the NGSS and is the cornerstone of the DataStreme courses. In particular, DataStreme ECS explores the fundamental science of Earth's climate system and addresses the societal impacts relevant to today's teachers and students. The course utilizes resources from respected organizations, such as the IPCC and U.S. Global Change Research Program. Key to the NGSS is that students learn disciplinary core ideas in the context of science and engineering practices. In order for the students to learn in this way, the AMS believes that it is important to train the teachers in this context. DataStreme ECS emphasizes investigation of real-word and current NASA and NOAA data. Participants also are made aware of NASA's EdGCM, a research-grade Global Climate Model where they can explore various future climate scenarios in the same way that actual research scientists do. The AMS DataStreme Project has received support from the National Science Foundation, NASA, and NOAA. Since 1996, more than 18,000 teachers have completed a DataStreme course, directly impacting hundreds of thousands of additional teachers and more than 1 million students.

Reforzando a los Alumnos Diversos Culturalmente y Linguisticamente con Aprendizaje. Traduccion de ERIC EC Digest #E500. (Empowering Culturally and Linguistically Diverse Students with Learning Problems). Translation of ERIC EC Digest #E500.

ERIC Educational Resources Information Center

Cummins, Jim

This digest describes ways in which professionals who work with students from culturally and linguistically diverse backgrounds can create an educational climate that accepts and respects the language and culture of its students and empowers them to feel confident enough to risk getting involved in the learning process. Methods of creating such an…

Cost of Behavioral Interventions Utilizing Electronic Drug Monitoring for Antiretroviral Therapy Adherence

PubMed Central

Rasu, Rafia S.; Malewski, David F.; Banderas, Julie W.; Thomson, Domonique Malomo; Goggin, Kathy

2013-01-01

Objective To provide data on the actual costs associated with behavioral ART adherence interventions and electronic drug monitoring used in a clinical trial to inform their implementation in future studies and real-world practice. Methods Direct and time costs were calculated from a multi-site three-arm randomized controlled ART adherence trial. HIV positive participants (n = 204) were randomized to standard care (SC), enhanced counseling (EC), or EC and modified directly observed therapy (mDOT) interventions. Electronic drug monitoring (EDM) was used. Costs were calculated for various components of the 24-week adherence intervention. This economic evaluation was conducted from the perspective of an agency that may wish to implement these strategies. Sensitivity analyses were conducted to examine costs and savings associated with different scenarios. Results Total direct costs were $126,068 ($618/patient). Initial time costs were $53,590 ($262/patient). Base cost of labor was $0.36/minute. EC costs for 134 patients were $18,427 ($137/patient) and mDOT for 64 patients cost $18,638 ($291/patient). Total per patient costs were: SC=$880, EC=$1,018, EC/mDOT=$1,309. Removing driving costs evidenced the most variable impact on savings between the three study arms. The tornado diagram (sensitivity analysis) showed a graphical representation of how each sensitivity assumption reduced costs compared to each other and the resulting comparative costs for each group. Conclusion This novel economic analysis provides valuable cost information to guide treatment implementation and research design decisions. PMID:23337364

Landscape evolution and agricultural land salinization in coastal area: A conceptual model.

PubMed

Bless, Aplena Elen; Colin, François; Crabit, Armand; Devaux, Nicolas; Philippon, Olivier; Follain, Stéphane

2018-06-01

Soil salinization is a major threat to agricultural lands. Among salt-affected lands, coastal areas could be considered as highly complex systems, where salinization degradation due to anthropogenic pressure and climate-induced changes could significantly alter system functioning. For such complex systems, conceptual models can be used as evaluation tools in a preliminary step to identify the main evolutionary processes responsible for soil and water salinization. This study aimed to propose a conceptual model for water fluxes in a coastal area affected by salinity, which can help to identify the relationships between agricultural landscape evolution and actual salinity. First, we conducted field investigations from 2012 to 2016, mainly based on both soil (EC 1/5 ) and water (EC w ) electrical conductivity survey. This allowed us to characterize spatial structures for EC 1/5 and EC w and to identify the river as a preponderant factor in land salinization. Subsequently, we proposed and used a conceptual model for water fluxes and conducted a time analysis (1962-2012) for three of its main constitutive elements, namely climate, river, and land systems. When integrated within the conceptual model framework, it appeared that the evolution of all constitutive elements since 1962 was responsible for the disruption of system equilibrium, favoring overall salt accumulation in the soil root zone. Copyright © 2017 Elsevier B.V. All rights reserved.

Acute sensitivity of white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) to copper, cadmium, or zinc in water-only laboratory exposures

PubMed Central

Calfee, Robin D; Little, Edward E; Puglis, Holly J; Scott, Erinn; Brumbaugh, William G; Mebane, Christopher A

2014-01-01

The acute toxicity of cadmium, copper, and zinc to white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) were determined for 7 developmental life stages in flow-through water-only exposures. Metal toxicity varied by species and by life stage. Rainbow trout were more sensitive to cadmium than white sturgeon across all life stages, with median effect concentrations (hardness-normalized EC50s) ranging from 1.47 µg Cd/L to 2.62 µg Cd/L with sensitivity remaining consistent during later stages of development. Rainbow trout at 46 d posthatch (dph) ranked at the 2nd percentile of a compiled database for Cd species sensitivity distribution with an EC50 of 1.46 µg Cd/L and 72 dph sturgeon ranked at the 19th percentile (EC50 of 3.02 µg Cd/L). White sturgeon were more sensitive to copper than rainbow trout in 5 of the 7 life stages tested with biotic ligand model (BLM)-normalized EC50s ranging from 1.51 µg Cu/L to 21.9 µg Cu/L. In turn, rainbow trout at 74 dph and 95 dph were more sensitive to copper than white sturgeon at 72 dph and 89 dph, indicating sturgeon become more tolerant in older life stages, whereas older trout become more sensitive to copper exposure. White sturgeon at 2 dph, 16 dph, and 30 dph ranked in the lower percentiles of a compiled database for copper species sensitivity distribution, ranking at the 3rd (2 dph), 5th (16 dph), and 10th (30 dph) percentiles. White sturgeon were more sensitive to zinc than rainbow trout for 1 out of 7 life stages tested (2 dph with an biotic ligand model–normalized EC50 of 209 µg Zn/L) and ranked in the 1st percentile of a compiled database for zinc species sensitivity distribution. Environ Toxicol Chem 2014;33:2259–2272. © 2014. The Authors. This article is a US government work and, as such, is in the public domain in the United States of America. Environmental Toxicology and Chemistry published byWiley Periodicals, Inc. on behalf of SETAC. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. PMID:25043712

Presurgical language localization with visual naming associated ECoG high- gamma modulation in pediatric drug-resistant epilepsy.

PubMed

Arya, Ravindra; Wilson, J Adam; Fujiwara, Hisako; Rozhkov, Leonid; Leach, James L; Byars, Anna W; Greiner, Hansel M; Vannest, Jennifer; Buroker, Jason; Milsap, Griffin; Ervin, Brian; Minai, Ali; Horn, Paul S; Holland, Katherine D; Mangano, Francesco T; Crone, Nathan E; Rose, Douglas F

2017-04-01

This prospective study compared presurgical language localization with visual naming-associated high-γ modulation (HGM) and conventional electrical cortical stimulation (ECS) in children with intracranial electrodes. Patients with drug-resistant epilepsy who were undergoing intracranial monitoring were included if able to name pictures. Electrocorticography (ECoG) signals were recorded during picture naming (overt and covert) and quiet baseline. For each electrode the likelihood of high-γ (70-116 Hz) power modulation during naming task relative to the baseline was estimated. Electrodes with significant HGM were plotted on a three-dimensional (3D) cortical surface model. Sensitivity, specificity, and accuracy were calculated compared to clinical ECS. Seventeen patients with mean age of 11.3 years (range 4-19) were included. In patients with left hemisphere electrodes (n = 10), HGM during overt naming showed high specificity (0.81, 95% confidence interval [CI] 0.78-0.85), and accuracy (0.71, 95% CI 0.66-0.75, p < 0.001), but modest sensitivity (0.47) when ECS interference with naming (aphasia or paraphasic errors) and/or oral motor function was regarded as the gold standard. Similar results were reproduced by comparing covert naming-associated HGM with ECS naming sites. With right hemisphere electrodes (n = 7), no ECS-naming deficits were seen without interference with oral-motor function. HGM mapping showed a high specificity (0.81, 95% CI 0.78-0.84), and accuracy (0.76, 95% CI 0.71-0.81, p = 0.006), but modest sensitivity (0.44) compared to ECS interference with oral-motor function. Naming-associated ECoG HGM was consistently observed over Broca's area (left posterior inferior-frontal gyrus), bilateral oral/facial motor cortex, and sometimes over the temporal pole. This study supports the use of ECoG HGM mapping in children in whom adverse events preclude ECS, or as a screening method to prioritize electrodes for ECS testing. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

High-grade endometrial carcinoma: serous and grade 3 endometrioid carcinomas have different immunophenotypes and outcomes.

PubMed

Alkushi, Abdulmohsen; Köbel, Martin; Kalloger, Steve E; Gilks, C Blake

2010-07-01

High-grade endometrial carcinomas are a heterogeneous group of tumors and include grade 3 endometrioid (EC-3), serous (SC), and clear cell carcinomas (CCC). There are conflicting data about the prognosis of these subtypes of high-grade endometrial carcinoma; this may be a result of lack of reproducibility in classifying tumor cell type. The purpose of this study was to examine differences in immunophenotype and outcome in a series of high-grade endometrial carcinomas, focusing on the comparison of EC-3 versus SC. We selected 180 endometrial carcinomas of SC, EC, or CCC type. No mixed carcinomas were included in the study. We chose the following immunohistochemical markers, estrogen receptor (ER), insulin-like growth factor 2 mRNA-binding protein 3 (IMP3), p16, p53, progesterone receptor (PR), and phosphatase and tensin homolog (PTEN) as being significantly differentially expressed in endometrial carcinoma subtypes. The tumors were stratified into 4 groups on the basis of their cell type and grade: EC grade 1 or 2, EC-3, SC, and CCC. Univariate survival analysis revealed significant differences in outcome between the 4 groups (P<0.0001), with significantly longer disease-specific survival for grade 1 or 2 EC versus EC-3 (P=0.0001), and EC-3 versus SC (P=0.0003). p16, PTEN, and IMP3 expression was observed more frequently in SC compared with EC-3 (P<0.0001, P=0.021, and P=0.031, respectively). These 3 markers showed the highest sensitivity and specificity in distinguishing between EC-3 and SC, with receiver operating characteristics area under the curve of 0.85, 0.69, and 0.71, respectively. ER and p53 approached but did not reach significance for differential expression in EC-3 versus SC (P=0.055 and P=0.068, respectively). A combination of p16 and PTEN predicts EC-3 versus SC with a sensitivity of 90.0% and specificity of 96.8%. p16 and PTEN can aid in distinguishing between EC-3 and SC of the endometrium, and are superior to ER, PR, and p53 for this purpose. EC-3 carcinomas have a significantly better prognosis than SC carcinomas of the endometrium.

Radiocarbon Analysis to Calculate New End-Member Values for Biomass Burning Source Samples Specific to the Bay Area

NASA Astrophysics Data System (ADS)

Yoon, S.; Kirchstetter, T.; Fairley, D.; Sheesley, R. J.; Tang, X.

2017-12-01

Elemental carbon (EC), also known as black carbon or soot, is an important particulate air pollutant that contributes to climate forcing through absorption of solar radiation and to adverse human health impacts through inhalation. Both fossil fuel combustion and biomass burning, via residential firewood burning, agricultural burning, wild fires, and controlled burns, are significant sources of EC. Our ability to successfully control ambient EC concentrations requires understanding the contribution of these different emission sources. Radiocarbon (14C) analysis has been increasingly used as an apportionment tool to distinguish between EC from fossil fuel and biomass combustion sources. However, there are uncertainties associated with this method including: 1) uncertainty associated with the isolation of EC to be used for radiocarbon analysis (e.g., inclusion of organic carbon, blank contamination, recovery of EC, etc.) 2) uncertainty associated with the radiocarbon signature of the end member. The objective of this research project is to utilize laboratory experiments to evaluate some of these uncertainties, particularly for EC sources that significantly impact the San Francisco Bay Area. Source samples of EC only and a mix of EC and organic carbon (OC) were produced for this study to represent known emission sources and to approximate the mixing of EC and OC that would be present in the atmosphere. These samples include a combination of methane flame soot, various wood smoke samples (i.e. cedar, oak, sugar pine, pine at various ages, etc.), meat cooking, and smoldering cellulose smoke. EC fractions were isolated using a Sunset Laboratory's thermal optical transmittance carbon analyzer. For 14C analysis, samples were sent to Woods Hole Oceanographic Institution for isotope analysis using an accelerated mass spectrometry. End member values and uncertainties for the EC isolation utilizing this method will be reported.

Global Framework for Climate Services (GFCS): status of implementation

NASA Astrophysics Data System (ADS)

Lucio, Filipe

2015-04-01

The World Climate Conference-3 (Geneva 2009) unanimously decided to establish the Global Framework for Climate Services (GFCS), a UN-led initiative spearheaded by WMO to guide the development and application of science-based climate information and services in support of decision-making in climate sensitive sectors. By promoting science-based decision-making, the GFCS is empowering governments, communities and companies to build climate resilience, reduce vulnerabilities and adapt to impacts. The initial priority areas of GFCS are Agriculture and Food Security; Disaster Risk Reduction; Health; and Water Resources. The implementation of GFCS is well underway with a governance structure now fully established. The governance structure of GFCS includes the Partner Advisory Committee (PAC), which is GFCS's stakeholder engagement mechanism. The membership of the PAC allows for a broad participation of stakeholders. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the European Commission (EC), the Food and Agriculture Organization of the UN (FAO), the Global Water Partnership (GWP), the International Federation of Red Cross and Red Crescent Societies (IFRC), the International Union of Geodesy and Geophysics (IUGG), United Nations Environment Programme (UNEP), the United Nations Institute for Training and Research (UNITAR), the World Business Council for Sustainable Development (WBCSD), the World Food Programme (WFP) and WMO have already joined the PAC. Activities are being implemented in various countries in Africa, the Caribbean, Asia and Pacific Small Islands Developing States through flagship projects and activities in the four priority areas of GFCS to enable the development of a Proof of Concept. The focus at national level is on strengthening institutional capacities needed for development of capacities for co-design and co-production of climate services and their application in support of decision-making in climate sensitive sectors. Establishment of regional capacities through climate centres to support national institutional capacities is a major focus. The Proof of Concept will be replicated in other parts of the world to ensure worldwide improvements in climate services for the four priority areas to facilitate the reduction of society's vulnerability to climate-related hazards and the advancement of the key global development goals. To streamline and harness climate research and knowledge in support of GFCS implementation, regional research plans or agendas are being shaped in different regions. For example, a Climate Research for Development Agenda for Africa (CR4D) is being developed under the leadership of the World Climate Research Programme (WCRP) and in cooperation with the African Union Commission and other partners. Similarly, regional climate research priorities are being developed for Latin America and the Caribbean, following the WCRP Conference for Latin America and the Caribbean (Montevideo, March 2014). Availability of regional research plans or agendas would ensure more effective research and involvement of national experts in climate research activities.

Estimating TCR using an integrated model-observation framework that accounts for spatio-temporal variability and pre-industrial radiative imbalances.

NASA Astrophysics Data System (ADS)

Haustein, K.; Schurer, A. P.; Venema, V.

2016-12-01

Apart from a few exceptions (e.g. Aldrin et al. 2012, Skeie et al. 2013) TCR estimates with EBMs are based on global data. Since these estimates don't represent the true spatial-temporal behaviour for observed temperature as well as external forcing (Marvel et al. 2015), we have developed a two-box EBM framework that accounts for these effects. In addition, external forcing from anthropogenic aerosol and GHGs tends to have different response times in comparison to volcanic stratospheric aerosols. Using PMIP3 and an extended ensemble of HadCM3 simulations (Euro500; Schurer et al. 2014) GCM simulations for the pre-industrial period, we obtain the fast and slow response time constants required in the EBM. With the most recent anthropogenic and natural forcing estimates, we test a range of TCR values against observations. The TCR/ECS ratio necessary to achieve that goal is taken from CMIP5 as observationally OHC-based estimates are notoriously unreliable. Given that observed and modelled OHC estimates are in agreement (Cheng et al. 2016), we argue that this should be the standard procedure the make inferences about ECS. Alternatively, it should be distinguished between equilibrium and effective climate sensitivity. The preliminary best estimate for TCR is 1.6K (1.1-2.2K) with an associated ECS value of 2.9K (2.0-4.0K). This is in good agreement with other D&A techniques that do use spatio-temporal patterns as well (e.g. Jones et al. 2016, Gillet et al. 2013). Correcting for natural ENSO variability and tas/tos-related inaccuracies (Richardson et al. 2016) further increases the robustness of the estimated sensitivity range. Our results also indicate that the small radiative imbalance caused by the period of very strong volcanic eruptions just before the CMIP5 historical period starts (1809-1840) has noteworthy implications for the response to later volcanic eruptions and the temperature evolution after 1850. Simply put, CMIP5-type simulations are slightly more sensitive to volcanic eruptions than PMIP3-type simulations. This has been pointed out in the literature before (e.g. Gleckler et al. 2006, Stenchikov et al. 2009, Gregory et al. 2010). We therefore argue that more PMIP3-type of experiments are needed to factor in the planetary energy imbalance caused by earlier volcanic eruptions.

Modeled dosage-response relationship on the net photosynthetic rate for the sensitivity to acid rain of 21 plant species.

PubMed

Deng, Shihuai; Gou, Shuzhen; Sun, Baiye; Lv, Wenlin; Li, Yuanwei; Peng, Hong; Xiao, Hong; Yang, Gang; Wang, Yingjun

2012-08-01

This study investigated the sensitivity of plant species to acid rain based on the modeled dosage-response relationship on the net photosynthetic rate (P (N)) of 21 types of plant species, subjected to the exposure of simulated acid rain (SAR) for 5 times during a period of 50 days. Variable responses of P (N) to SAR occurred depending on the type of plant. A majority (13 species) of the dosage-response relationship could be described by an S-shaped curve and be fitted with the Boltzmann model. Model fitting allowed quantitative evaluation of the dosage-response relationship and an accurate estimation of the EC(10), termed as the pH of the acid rain resulting in a P (N) 10 % lower than the reference value. The top 9 species (Camellia sasanqua, Cinnamomum camphora, etc. EC(10) ≤ 3.0) are highly endurable to very acid rain. The rare, relict plant Metasequoia glyptostroboides was the most sensitive species (EC(10) = 5.1) recommended for protection.

Retrieval of atmospheric elemental carbon records using lake sediments: Implications in radiative forcing

NASA Astrophysics Data System (ADS)

Ahmed, Tanveer

Elemental or black carbon (EC or BC) aerosols produced during incomplete combustion strongly absorb solar radiation and contribute to global warming, and cause cardiopulmonary disease. Long-term atmospheric EC measurements, [EC]atm, are needed to validate global climate models to estimate the impact of EC on earth's temperature. Such data is sparse. In this work, a new technique was developed to retrieve the historical record of [EC]atm in the Northeastern US for the past two centuries. Measurements of [EC]atm were made in the monthly composites of daily filters collected over ˜30 yr at Whiteface Mountain (WFM), NY using the thermal optical method. Bottom sediment cores were collected from four lakes near WFM. They were sliced in horizontal sections, freeze dried, and their ages determined 210Pb dating technique. EC in sediments was chemically separated and its concentration determined using the same thermal-optical method. It was shown that [EC]sed = K [EC]atm where K is constant (m3/g). Measurements of [EC]atm and [EC]sed for the ˜1978 to 2005 period was used to determine the value for K. The value of K and [EC]sed for periods before 1978 were used to determine [EC]atm for the past ˜100 yrs. [EC]atm in the preindustrial period in US, ˜1850, varied between 38 and 73 ng/m3, with a mean value of 56 +/- 14 ng/m3. [EC]atm was found to increase sharply with rapid industrialization and reached its maximum value of 751 +/- 265 ng/m3 during 1920s, which was a factor of ˜12 higher compared to the mean preindustrial level. The [EC]atm declined gradually until ˜1980 and then decreased sharply. Directly measured values of [EC]atm are only ˜25% higher compared to the mean preindustrial level. Model US EC emissions estimates of Novakov et al. (2003), based on energy consumptions, reproduce our [EC]sed trends quite well for the ˜1900 to 1930 period. Subsequently, the model EC values drop-off more rapidly than our [EC]atm. To extend the technique where long tern [EC]atm are not available, a new generalized mathematical model expression to determine K was developed. The value of K calculated using the model agreed within +/-30% with the measurements.

On the isolation of elemental carbon for micro-molar 14C accelerator mass spectrometry; evaluation of alternative isolation procedures, and accuracy assurance using a hybrid isotopic particulate carbon reference material

NASA Astrophysics Data System (ADS)

Currie, L. A.; Kessler, J. D.

2005-05-01

The primary objective of the research reported here has been the development of an hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are critically important for the quantitative apportionment of fossil and biomass sources of ''soot'' (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the ''truth'' was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC) of measurement validity (Currie et al., 2002). Components of the new Hybrid RM (DiesApple), however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14C, and its major compositional component is EC. SRM 1515 (Apple Leaves) has the 14C content of biomass-C, and it has little or no EC. Thus, the hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C from SRM 1515 in the EC isolate of the hybrid RM, together with testing for conservation of its dominant soot fraction through the isolation procedure.

PROBING ELECTRON-CAPTURE SUPERNOVAE: X-RAY BINARIES IN STARBURSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linden, T.; Sepinsky, J. F.; Kalogera, V.

We develop population models of high-mass X-ray binaries (HMXBs) formed after bursts of star formation and we investigate the effect of electron-capture supernovae (ECS) of massive ONeMg white dwarfs and the hypothesis that ECS events are associated with typically low supernova kicks imparted to the nascent neutron stars. We identify an interesting ECS bump in the time evolution of HMXB numbers; this bump is caused by significantly increased production of wind-fed HMXBs 20-60 Myr post-starburst. The amplitude and age extent of the ECS bump depend on the strength of ECS kicks and the mass range of ECS progenitors. We alsomore » find that ECS-HMXBs form through a specific evolutionary channel that is expected to lead to binaries with Be donors in wide orbits. These characteristics, along with their sensitivity to ECS properties, provide us with an intriguing opportunity to probe ECS physics and progenitors through studies of starbursts of different ages. Specifically, the case of the Small Magellanic Cloud, with a significant observed population of Be-HMXBs and starburst activity 30-60 Myr ago, arises as a promising laboratory for understanding the role of ECS in neutron star formation.« less

Comprehensive characterization of the acute and chronic toxicity of the neonicotinoid insecticide thiamethoxam to a suite of aquatic primary producers, invertebrates, and fish.

PubMed

Finnegan, Meaghean C; Baxter, Leilan R; Maul, Jonathan D; Hanson, Mark L; Hoekstra, Paul F

2017-10-01

Thiamethoxam is a neonicotinoid insecticide used widely in agriculture to control a broad spectrum of chewing and sucking insect pests. Recent detection of thiamethoxam in surface waters has raised interest in characterizing the potential impacts of this insecticide to aquatic organisms. We report the results of toxicity testing (acute and chronic) conducted under good laboratory practices for more than 30 freshwater species (insects, molluscs, crustaceans, algae, macrophytes, and fish) and 4 marine species (an alga, a mollusc, a crustacean, and a fish). As would be anticipated for a neonicotinoid, aquatic primary producers and fish were the least sensitive organisms tested, with acute median lethal and effect concentrations (LC50/EC50) observed to be ≥80 mg/L in all cases, which far exceeds surface water exposure concentrations. Tested molluscs, worms, and rotifers were similarly insensitive (EC50 ≥ 100 mg/L), except for Lumbriculus sp., with an EC50 of 7.7 mg/L. In general, insects were the most sensitive group in the study, with most acute EC50 values < 1 mg/L. However, the crustaceans Asellus aquaticus and Ostracoda exhibited a sensitivity similar to that of insects (acute EC50 < 1 mg/L), and the midge larvae Chaoborus sp. were relatively insensitive compared with other insects (EC50 > 5.5 mg/L). The most sensitive chronic response was for Chironomus riparius, with a 30-d no-observed-effect concentration (NOEC; emergence) of 0.01 mg/L. Observed toxicity to the tested marine organisms was comparable to that of freshwater species. We used the reported data to construct species sensitivity distributions for thiamethoxam, to calculate 5% hazard concentrations (HC5s) for acute data (freshwater invertebrates), and compared these with measured concentrations from relevant North American surface waters. Overall, based on acute toxicity endpoints, the potential acute risk to freshwater organisms was found to be minimal (likelihood of exceeding HC5s < 1%). Environ Toxicol Chem 2017;36:2838-2848. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc.

Leaf Dynamics of Panicum maximum under Future Climatic Changes

PubMed Central

Britto de Assis Prado, Carlos Henrique; Haik Guedes de Camargo-Bortolin, Lívia; Castro, Érique; Martinez, Carlos Alberto

2016-01-01

Panicum maximum Jacq. ‘Mombaça’ (C4) was grown in field conditions with sufficient water and nutrients to examine the effects of warming and elevated CO2 concentrations during the winter. Plants were exposed to either the ambient temperature and regular atmospheric CO2 (Control); elevated CO2 (600 ppm, eC); canopy warming (+2°C above regular canopy temperature, eT); or elevated CO2 and canopy warming (eC+eT). The temperatures and CO2 in the field were controlled by temperature free-air controlled enhancement (T-FACE) and mini free-air CO2 enrichment (miniFACE) facilities. The most green, expanding, and expanded leaves and the highest leaf appearance rate (LAR, leaves day-1) and leaf elongation rate (LER, cm day-1) were observed under eT. Leaf area and leaf biomass were higher in the eT and eC+eT treatments. The higher LER and LAR without significant differences in the number of senescent leaves could explain why tillers had higher foliage area and leaf biomass in the eT treatment. The eC treatment had the lowest LER and the fewest expanded and green leaves, similar to Control. The inhibitory effect of eC on foliage development in winter was indicated by the fewer green, expanded, and expanding leaves under eC+eT than eT. The stimulatory and inhibitory effects of the eT and eC treatments, respectively, on foliage raised and lowered, respectively, the foliar nitrogen concentration. The inhibition of foliage by eC was confirmed by the eC treatment having the lowest leaf/stem biomass ratio and by the change in leaf biomass-area relationships from linear or exponential growth to rectangular hyperbolic growth under eC. Besides, eC+eT had a synergist effect, speeding up leaf maturation. Therefore, with sufficient water and nutrients in winter, the inhibitory effect of elevated CO2 on foliage could be partially offset by elevated temperatures and relatively high P. maximum foliage production could be achieved under future climatic change. PMID:26894932

Comparing student and staff perceptions of the "Educational Climate" in Spanish Dental Schools using the Dundee Ready Education Environment Measure.

PubMed

Tomás, I; Aneiros, A; Casares-de-Cal, M A; Quintas, V; Prada-López, I; Balsa-Castro, C; Ceballos, L; Gómez-Moreno, G; Llena, C; López-Jornet, P; Machuca, M C; Palés, J

2018-02-01

To compare the perceptions of students and teachers of the "Educational Climate" (EC) in Spanish public dental schools. A group of 1064 students and 354 teachers from six Spanish public dental schools responded to the DREEM questionnaire. This has 50 items grouped into five subscales: perception of learning (Learning); perception of teachers (Teachers); academic self-perceptions (Academic); perception of the atmosphere in the faculty (Atmosphere); and social self-perceptions (Social). The DREEM scale provides results for each item, each subscale and the overall EC. The EC scores were 123.2 (61.6%) for the students and 134.1 (67.0%) for the teachers (P<.001). The scores of the students and teachers for the subscales were, respectively: 27.9 (58.1%) and 30.2 (63.0 %) for Learning (P<.001); 26.8 (60.9%) and 32.6 (74.1%) for Teachers (P<.001); 20.7 (64.7%) and 20.5 (64.0%) for Academic (P=.333); 29.9 (62.3%) and 33.7 (70.3%) for Atmosphere (P<.001); and 17.9 (64.0%) and 16.9 (60.5%) for Social (P<.001). The students identified six problematic items (12.0 %) compared to only two (4.0 %) highlighted by the teachers. The students and teachers considered the EC to be "more positive than negative" in Spanish public dental schools; and the different subscales to be "positive and acceptable." The teachers did, however, evaluate the EC, and specifically the learning-teaching process, more positively than their students, identifying fewer problematic educational aspects. Both groups agreed on the need to: improve support systems for students who suffer from stress and reduce teaching based on "factual learning." © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Conventional and Nuclear Medicine Imaging in Ectopic Cushing's Syndrome: A Systematic Review.

PubMed

Isidori, Andrea M; Sbardella, Emilia; Zatelli, Maria Chiara; Boschetti, Mara; Vitale, Giovanni; Colao, Annamaria; Pivonello, Rosario

2015-09-01

Ectopic Cushing's Syndrome (ECS) can be a diagnostic challenge with the hormonal source difficult to find. This study analyzes the accuracy of imaging studies in ECS localization. Systematic review of medical literature for ECS case series providing individual patient data on at least one conventional imaging technique (computed tomography [CT]/magnetic resonance imaging) and one of the following: 111In-pentetreotide (OCT), 131I/123I-metaiodobenzylguanidine, 18Ffluoro-2-deoxyglucose-positron emission tomography (FDG-PET), 18F-fluorodopa-PET (F-DOPA-PET), 68Ga- DOTATATE-PET/CT or 68Ga-DOTATOC-PET/CT scan (68Gallium-SSTR-PET/CT). The analysis comprised 231 patients (females, 50.2%; age, 42.617 y). Overall, 52.4%(121/231) had "overt" ECS,18.6% had "occult" ECS, and 29% had "covert" ECS. Tumors were located in the lung (55.3%), mediastinum-thymus (7.9%), pancreas (8.5%), adrenal glands (6.4%), gastrointestinal tract (5.4%), thyroid (3.7%), and other sites (12.8%), and primary tumors were mostly bronchial neuroendocrine tumors (NETs) (54.8%), pancreatic NETs (8%), mediastinum-thymus NETs (6.9%), gastrointestinal NETs (5.3%), pheochromocytoma (6.4%), neuroblastoma (3.2%), and medullary thyroid carcinoma (3.2%). Tumors were localized byCTin66.2%(137/207), magnetic resonance imaging in 51.5% (53/103), OCT in 48.9% (84/172), FDG-PET in 51.7% (46/89), F-DOPAPET in 57.1% (12/21), 131/123I-metaiodobenzylguanidine in 30.8% (4/13), and 68Gallium-SSTRPET/CT in 81.8% (18/22) of cases. Molecular imaging discovered 79.1% (53/67) of tumors unidentified by conventional radiology, with OCT the most commonly used, revealing the tumor in 64%, followed by FDG-PET in 59.4%. F-DOPA-PET was used in only seven covert cases (sensitivity, 85.7%). Notably, 68Gallium-SSTR-PET/CT had 100% sensitivity among covert cases. Nuclear medicine improves the sensitivity of conventional radiology when tumor site identification is problematic. OCT offers a good availability/reliability ratio, and FDG-PET was proven useful. 68Gallium-SSTR-PET/CT use was infrequent, despite offering the highest sensitivity.

Activin receptor-like kinase 5 inhibition reverses impairment of endothelial cell viability by endogenous islet mesenchymal stromal cells.

PubMed

Clarkin, Claire E; King, Aileen J; Dhadda, Paramjeet; Chagastelles, Pedro; Nardi, Nance; Wheeler-Jones, Caroline P; Jones, Peter M

2013-03-01

Following islet transplantation, islet graft revascularization is compromised due to loss of endothelial cells (ECs) during islet culture. TGF-β signaling pathways are essential for vascular homeostasis but their importance for islet EC function is unclear. We have identified a population of multipotent mesenchymal stromal cells (MSCs) within islets and investigated how modulation of TGF-β signaling by these cells influences islet EC viability. Cultured islets exhibited reduced expression of EC markers (VEGFR2, VE-cadherin and CD31), which was associated with diminished but sustained expression of endoglin a marker of both ECs and MSCs. Double fluorescent labeling of islets in situ with the EC marker CD31 disclosed a population of CD31-negative cells which were positive for endoglin. In vitro coculture of microvascular ECs with endoglin-positive, CD31-negative islet MSCs reduced VEGFR2 protein expression, disrupted EC angiogenic behavior, and increased EC detachment. Medium conditioned by islet MSCs significantly decreased EC viability and increased EC caspase 3/7 activity. EC:MSC cocultures showed enhanced Smad2 phosphorylation consistent with altered ALK5 signaling. Pharmacological inhibition of ALK5 activity with SB431542 (SB) improved EC survival upon contact with MSCs, and SB-treated cultured islets retained EC marker expression and sensitivity to exogenous VEGF164 . Thus, endoglin-expressing islet MSCs influence EC ALK5 signaling in vitro, which decreases EC viability, and changes in ALK5 activity in whole cultured islets contribute to islet EC loss. Modifying TGF-β signaling may enable maintenance of islet ECs during islet isolation and thus improve islet graft revascularization post-transplantation. Copyright © 2013 AlphaMed Press.

Advances on the determination of thresholds of Cu phytotoxicity in field-contaminated soils in central Chile.

PubMed

Mondaca, Pedro; Catrin, Joanie; Verdejo, José; Sauvé, Sébastien; Neaman, Alexander

2017-04-01

To better determine phytotoxicity thresholds for metals in the soil, studies should use actual field-contaminated soil samples rather than metal-spiked soil preparations. However, there are surprisingly few such data available for Cu phytotoxicity in field-contaminated soils. Moreover, these studies differ from each other with regards to soil characteristics and experimental setups. This study aimed at more accurately estimating Cu phytotoxicity thresholds using field-collected agricultural soils (Entisols) from areas exposed to contamination from Cu mining. For this purpose, the exposure to Cu was assessed by measuring total soil Cu, soluble Cu, free Cu 2+ activity, and Cu in the plant aerial tissues. On the other hand, two bioassay durations (short-term and long-term), three plant species (Avena sativa L., Brassica rapa CrGC syn. Rbr, and Lolium perenne L.), and five biometric endpoints (shoot length and weight, root length and weight, and number of seed pods) were considered. Overall plant growth was best predicted by total Cu content of the soil. Despite some confounding factors, it was possible to determine EC 10 , EC 25 and EC 50 of total Cu in the soil. Brassica rapa was more sensitive than Avena sativa for all endpoints, while Lolium perenne was of intermediate sensitivity. For the short-term bioassay (21 days for all three species), the averaged EC 10 , EC 25 and EC 50 values of total soil Cu (in mg kg -1 ) were 356, 621, and 904, respectively. For the long-term bioassay (62 days for oat and 42 days for turnip), the averaged EC 10 , EC 25 and EC 50 values of total soil Cu (in mg kg -1 ) were 355, 513, and 688, respectively. The obtained results indicate that chronic test is a suitable method for assessing Cu phytotoxicity in field-contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brock, T.A.; Brugnara, C.; Canessa, M.

The authors have characterized a Na/sup +/-K/sup +/-Cl/sup -/ cotransporter in vascular endothelial cells (EC) cultured from different blood vessels and species that is inhibited by the diuretics furosemide and bumentanide. Inward /sup 86/Rb influx transported by the Na/sup +/-K/sup +/ pump in cultured EC from bovine and pig aorta, bovine vena cava, and baboon cephalic vein but not in human umbilical or saphenous vein EC. External Na/sup +/ or Cl/sup -/-stimulated, ouabain-insensitive /sup 86/Rb influx is equal to furosemide or bumetanide-sensitive /sup 86/Rb influx. Ouabain-insensitive /sup 22/Na influx is also partially inhibited by these drugs and stimulated by increasingmore » external K/sup +/ or Cl/sup -/. Net Na/sup +/ extrusion occurs via the Na/sup +/-K/sup +/-Cl/sup -/ cotransporter in the absence of external K/sup +/, whereas net Na/sup +/ influx occurs at higher external K/sup +/. Maximal concentrations (100 nM) of bradykinin and vasopressin increase the initial rate of bumetanide-sensitive /sup 86/Rb influx by approx.60 and 70%. Addition of either ethyleneglycol-bis(..beta..-aminotethylether)-N,N'-tetraacetic acid or LaCl/sub 3/ (to block calcium influx) prevents bradykinin-stimulated /sup 86/Rb influx. When intracellular calcium is elevated using ionomycin (100 nM), a Ca/sup 2 +/ionophore, bumetanide-sensitive /sup 86/Rb influx increases approx.twofold. In contrast, isoproterenol (100 ..mu..M) and forskolin (50 /sup +/M), adenylate cyclase stimulators, decrease furosemide-sensitive /sup 86/Rb influx. Thus in certain types of cultured EC, a Na/sup +/-K/sup +/-Cl/sup -/ cotransporter mediates a fraction of K/sup +/ influx quantitatively as important as the Na/sup +/-K/sup +/ pump (ouabain-sensitive /sup 86/Rb influx) and appears to be modulated by Ca/sup 2 +/ and cyclic nucleotides.« less

Estimating skin sensitization potency from a single dose LLNA.

PubMed

Roberts, David W

2015-04-01

Skin sensitization is an important aspect of safety assessment. The mouse local lymph node assay (LLNA) developed in the 1990 s is an in vivo test used for skin sensitization hazard identification and characterization. More recently a reduced version of the LLNA (rLLNA) has been developed as a means of identifying, but not quantifying, sensitization hazard. The work presented here is aimed at enabling rLLNA data to be used to give quantitative potency information that can be used, inter alia, in modeling and read-across approaches to non-animal based potency estimation. A probit function has been derived enabling estimation of EC3 from a single dose. This has led to development of a modified version of the rLLNA, whereby as a general principle the SI value at 10%, or at a lower concentration if 10% is not testable, is used to calculate the EC3. This version of the rLLNA has been evaluated against a selection of chemicals for which full LLNA data are available, and has been shown to give EC3 values in good agreement with those derived from the full LLNA. Copyright © 2015 Elsevier Inc. All rights reserved.

Nudging the Arctic Ocean to quantify Arctic sea ice feedbacks

NASA Astrophysics Data System (ADS)

Dekker, Evelien; Severijns, Camiel; Bintanja, Richard

2017-04-01

It is well-established that the Arctic is warming 2 to 3 time faster than rest of the planet. One of the great uncertainties in climate research is related to what extent sea ice feedbacks amplify this (seasonally varying) Arctic warming. Earlier studies have analyzed existing climate model output using correlations and energy budget considerations in order to quantify sea ice feedbacks through indirect methods. From these analyses it is regularly inferred that sea ice likely plays an important role, but details remain obscure. Here we will take a different and a more direct approach: we will keep the sea ice constant in a sensitivity simulation, using a state-of -the-art climate model (EC-Earth), applying a technique that has never been attempted before. This experimental technique involves nudging the temperature and salinity of the ocean surface (and possibly some layers below to maintain the vertical structure and mixing) to a predefined prescribed state. When strongly nudged to existing (seasonally-varying) sea surface temperatures, ocean salinity and temperature, we force the sea ice to remain in regions/seasons where it is located in the prescribed state, despite the changing climate. Once we obtain fixed' sea ice, we will run a future scenario, for instance 2 x CO2 with and without prescribed sea ice, with the difference between these runs providing a measure as to what extent sea ice contributes to Arctic warming, including the seasonal and geographical imprint of the effects.

Improving the complementary methods to estimate evapotranspiration under diverse climatic and physical conditions

NASA Astrophysics Data System (ADS)

Anayah, F. M.; Kaluarachchi, J. J.

2014-06-01

Reliable estimation of evapotranspiration (ET) is important for the purpose of water resources planning and management. Complementary methods, including complementary relationship areal evapotranspiration (CRAE), advection aridity (AA) and Granger and Gray (GG), have been used to estimate ET because these methods are simple and practical in estimating regional ET using meteorological data only. However, prior studies have found limitations in these methods especially in contrasting climates. This study aims to develop a calibration-free universal method using the complementary relationships to compute regional ET in contrasting climatic and physical conditions with meteorological data only. The proposed methodology consists of a systematic sensitivity analysis using the existing complementary methods. This work used 34 global FLUXNET sites where eddy covariance (EC) fluxes of ET are available for validation. A total of 33 alternative model variations from the original complementary methods were proposed. Further analysis using statistical methods and simplified climatic class definitions produced one distinctly improved GG-model-based alternative. The proposed model produced a single-step ET formulation with results equal to or better than the recent studies using data-intensive, classical methods. Average root mean square error (RMSE), mean absolute bias (BIAS) and R2 (coefficient of determination) across 34 global sites were 20.57 mm month-1, 10.55 mm month-1 and 0.64, respectively. The proposed model showed a step forward toward predicting ET in large river basins with limited data and requiring no calibration.

Nutritional, Biophysical and Physiological Characteristics of Wild Rocket Genotypes As Affected by Soilless Cultivation System, Salinity Level of Nutrient Solution and Growing Period

PubMed Central

Bonasia, Anna; Lazzizera, Corrado; Elia, Antonio; Conversa, Giulia

2017-01-01

With the aim of defining the best management of nutrient solution (NS) in a soilless system for obtaining high quality baby-leaf rocket, the present study focuses on two wild rocket genotypes (“Nature” and “Naturelle”), grown in a greenhouse under two Southern Italy growing conditions—autumn-winter (AW) and winter-spring (WS)—using two soilless cultivation systems (SCS)—at two electrical conductivity values (EC) of NS. The SCSs used were the Floating System (FS) and Ebb and Flow System (EFS) and the EC values were 2.5 and 3.5 dS m−1 (EC2.5; EC3.5) for the AW cycle and 3.5 and 4.5 dS m−1 (EC3.5; EC4.5) for the WS cycle. The yield, bio-physical, physiological and nutritional characteristics were evaluated. Higher fresh (FY) (2.25 vs. 1.50 kg m−2) and dry (DY) (230.6 vs. 106.1 g m−2) weight yield, leaf firmness (dry matter, 104.3 vs. 83.2 g kg−1 FW; specific leaf area, 34.8 vs. 24.2 g cm−2) and antioxidant compounds (vitamin C, 239.0 vs. 152.7 mg kg−1 FW; total phenols, 997 vs. 450 mg GAE mg kg−1 FW; total glucosinulates-GLSs, 1,078.8 vs. 405.7 mg kg−1 DW; total antioxidant capacity-TAC, 11,534 vs. 8,637 μmol eq trolox kg−1 FW) and lower nitrates (1,470 vs. 3,460 mg kg−1 FW) were obtained under WS conditions. The seasonal differences were evident on the GLS profile: some aliphatic GLSs (gluconapoleiferin, glucobrassicanapin) and indolic 4-OH-glucobrassicin were only expressed in WS conditions, while indolic glucobrassicin was only detected in the AW period. Compared with EFS, FS improved leaf firmness, visual quality, antioxidant content (TAC, +11.6%) and reduced nitrate leaf accumulation (−37%). “Naturelle” performed better than “Nature” in terms of yield, visual quality and nutritional profile, with differences more evident under less favorable climatic conditions and when the cultivars were grown in FS. Compared to EC2.5, the EC3.5 treatment did not affect DY while enhancing firmness, visual quality, and antioxidant compounds (TAC, +8%), and reducing the nitrate content (−47%). The EC4.5 treatment reduced FY and DY and the antioxidant content. Despite seasonal climatic condition variability, FS and the moderate salinity level of NS (3.5 dS m−1) can be suggested as optimum. PMID:28337211

Nutritional, Biophysical and Physiological Characteristics of Wild Rocket Genotypes As Affected by Soilless Cultivation System, Salinity Level of Nutrient Solution and Growing Period.

PubMed

Bonasia, Anna; Lazzizera, Corrado; Elia, Antonio; Conversa, Giulia

2017-01-01

With the aim of defining the best management of nutrient solution (NS) in a soilless system for obtaining high quality baby-leaf rocket, the present study focuses on two wild rocket genotypes ("Nature" and "Naturelle"), grown in a greenhouse under two Southern Italy growing conditions-autumn-winter (AW) and winter-spring (WS)-using two soilless cultivation systems (SCS)-at two electrical conductivity values (EC) of NS. The SCSs used were the Floating System (FS) and Ebb and Flow System (EFS) and the EC values were 2.5 and 3.5 dS m -1 (EC2.5; EC3.5) for the AW cycle and 3.5 and 4.5 dS m -1 (EC3.5; EC4.5) for the WS cycle. The yield, bio-physical, physiological and nutritional characteristics were evaluated. Higher fresh (FY) (2.25 vs. 1.50 kg m -2 ) and dry (DY) (230.6 vs. 106.1 g m -2 ) weight yield, leaf firmness (dry matter, 104.3 vs. 83.2 g kg -1 FW; specific leaf area, 34.8 vs. 24.2 g cm -2 ) and antioxidant compounds (vitamin C, 239.0 vs. 152.7 mg kg -1 FW; total phenols, 997 vs. 450 mg GAE mg kg -1 FW; total glucosinulates-GLSs, 1,078.8 vs. 405.7 mg kg -1 DW; total antioxidant capacity-TAC, 11,534 vs. 8,637 μmol eq trolox kg -1 FW) and lower nitrates (1,470 vs. 3,460 mg kg -1 FW) were obtained under WS conditions. The seasonal differences were evident on the GLS profile: some aliphatic GLSs (gluconapoleiferin, glucobrassicanapin) and indolic 4-OH-glucobrassicin were only expressed in WS conditions, while indolic glucobrassicin was only detected in the AW period. Compared with EFS, FS improved leaf firmness, visual quality, antioxidant content (TAC, +11.6%) and reduced nitrate leaf accumulation (-37%). "Naturelle" performed better than "Nature" in terms of yield, visual quality and nutritional profile, with differences more evident under less favorable climatic conditions and when the cultivars were grown in FS. Compared to EC2.5, the EC3.5 treatment did not affect DY while enhancing firmness, visual quality, and antioxidant compounds (TAC, +8%), and reducing the nitrate content (-47%). The EC4.5 treatment reduced FY and DY and the antioxidant content. Despite seasonal climatic condition variability, FS and the moderate salinity level of NS (3.5 dS m -1 ) can be suggested as optimum.

The impact of climate change on the drought variability over Australia

NASA Astrophysics Data System (ADS)

Kirono, D. G. C.; Hennessy, K.; Mpelasoka, F.; Bathols, J.; Kent, D.

2009-04-01

Drought has significant environmental and socio-economic impacts in Australia. Government assistance for drought events is guided by the current National Drought Policy (NDP). The Commonwealth Government provides support to farmers and rural communities under the Exceptional Circumstances (EC) arrangements and other drought programs, while state and territory governments also participate in the NDP and provide support measures of their own. To be classified as an EC event, the event must be rare, that is must not have occurred more than once on average in every 20-25 years. Given the likely increase in the area of the world affected by droughts in future due to climate change (IPCC, 2007), this paper presents assessments on how climate change may affect the concept of a one in 20-25 year event into the future for Australia. As droughts can be experienced and defined in different ways, many drought indices are available to monitor and to assess drought conditions. Commonly, these indices are categorised into four types: meteorological, hydrological, agricultural, and socio-economic. The meteorological drought indices are more widely used because they require data that are readily available and that they are relatively easy to calculate. However, meteorological drought indices based on rainfall alone fail to include the important contribution of evaporation. Here, the assessment is made using outputs of 13 global climate models (GCMs) and a meteorological drought index called the Reconnaissance Drought Index (RDI). It incorporates the aggregated deficits between the rainfall and the evaporative demand of the atmosphere. If the RDI were the sole trigger for EC declarations, then the mean projections indicate that more declarations would be likely in the future. As a comparison, results from an assessment based on other measures (temperature, rainfall, and soil wetness) will also be presented. IPCC, 2007: Climate Change 2007 - The physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (eds. Solomon, S. et al.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, www.ipcc.ch

Sensitivity of Inverse Estimation of 2004 Elemental Carbon Emissions Inventory in the United States to the Choice of Observational Networks

EPA Science Inventory

Choice of observational networks used for inverse re-estimation of elemental (or black) carbon (EC) emissions in the United States impacts results. We convert the Thermal Optical Transmittance (TOT) EC measurements to the Thermal Optical Reflectance (TOR) equivalent to make full...

Sensitivity limits and EC50 values of the Vibrio fischeri test for organic micropollutants in natural and spiked extracts from sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salizzato, M.; Bertato, V.; Pavoni, B.

1998-04-01

Chemical analyses and bioassays were used in conjunction to assess the quality of sediments of the Venice lagoon. Organic micropollutants (polycyclic aromatic hydrocarbons [PAHs] polychlorinated biphenyls [PCBs], and chlorinated pesticides) were extracted from sediment samples and analyzed by gas chromatography after fractionation into classes of compounds. The Vibrio fischeri test was used to assess the acute toxicity of sediment extracts. The test was applied to organic extracts before cleanup and to extracts purified from sulfur and fractionated into single classes of compounds. Extracts before purification were much more toxic than single fractions. In particular, sulfur was toxic to V. fischeri.more » For PAHs and PCBs the 50% effective concentration (EC50) and EC20 values were determined using natural and spiked extracts. Sensitivity limits of the method for these compounds were also estimated as was in EC50 value of elemental sulfur dissolved in ethanol. A mathematical model was used to fit the concentration-response data to a sigmoid curve.« less

A Contact-Based Method for Differentiation of Human Mesenchymal Stem Cells into an Endothelial Cell-Phenotype.

PubMed

Joddar, Binata; Kumar, Shweta Anil; Kumar, Alok

2018-06-01

Adult stem cells such as mesenchymal stem cells (MSC) are known to possess the ability to augment neovascularization processes and are thus widely popular as an autologous source of progenitor cells. However there is a huge gap in our current knowledge of mechanisms involved in differentiating MSC into endothelial cells (EC), essential for lining engineered blood vessels. To fill up this gap, we attempted to differentiate human MSC into EC, by culturing the former onto chemically fixed layers of EC or its ECM, respectively. We expected direct contact of MSC when cultured atop fixed EC or its ECM, would coax the former to differentiate into EC. Results showed that human MSC cultured atop chemically fixed EC or its ECM using EC-medium showed enhanced expression of CD31, a marker for EC, compared to other cases. Further in all human MSC cultured using EC-medium, typically characteristic cobble stone shaped morphologies were noted in comparison to cells cultured using MSC medium, implying that the differentiated cells were sensitive to soluble VEGF supplementation present in the EC-medium. Results will enhance and affect therapies utilizing autologous MSC as a cell source for generating vascular cells to be used in a variety of tissue engineering applications.

Origin of elemental carbon in snow from western Siberia and northwestern European Russia during winter-spring 2014, 2015 and 2016

NASA Astrophysics Data System (ADS)

Evangeliou, Nikolaos; Shevchenko, Vladimir P.; Espen Yttri, Karl; Eckhardt, Sabine; Sollum, Espen; Pokrovsky, Oleg S.; Kobelev, Vasily O.; Korobov, Vladimir B.; Lobanov, Andrey A.; Starodymova, Dina P.; Vorobiev, Sergey N.; Thompson, Rona L.; Stohl, Andreas

2018-01-01

Short-lived climate forcers have been proven important both for the climate and human health. In particular, black carbon (BC) is an important climate forcer both as an aerosol and when deposited on snow and ice surface because of its strong light absorption. This paper presents measurements of elemental carbon (EC; a measurement-based definition of BC) in snow collected from western Siberia and northwestern European Russia during 2014, 2015 and 2016. The Russian Arctic is of great interest to the scientific community due to the large uncertainty of emission sources there. We have determined the major contributing sources of BC in snow in western Siberia and northwestern European Russia using a Lagrangian atmospheric transport model. For the first time, we use a recently developed feature that calculates deposition in backward (so-called retroplume) simulations allowing estimation of the specific locations of sources that contribute to the deposited mass. EC concentrations in snow from western Siberia and northwestern European Russia were highly variable depending on the sampling location. Modelled BC and measured EC were moderately correlated (R = 0.53-0.83) and a systematic region-specific model underestimation was found. The model underestimated observations by 42 % (RMSE = 49 ng g-1) in 2014, 48 % (RMSE = 37 ng g-1) in 2015 and 27 % (RMSE = 43 ng g-1) in 2016. For EC sampled in northwestern European Russia the underestimation by the model was smaller (fractional bias, FB > -100 %). In this region, the major sources were transportation activities and domestic combustion in Finland. When sampling shifted to western Siberia, the model underestimation was more significant (FB < -100 %). There, the sources included emissions from gas flaring as a major contributor to snow BC. The accuracy of the model calculations was also evaluated using two independent datasets of BC measurements in snow covering the entire Arctic. The model underestimated BC concentrations in snow especially for samples collected in springtime.

Aquatic Eddy Correlation: Quantifying the Artificial Flux Caused by Stirring-Sensitive O2 Sensors

PubMed Central

Holtappels, Moritz; Noss, Christian; Hancke, Kasper; Cathalot, Cecile; McGinnis, Daniel F.; Lorke, Andreas; Glud, Ronnie N.

2015-01-01

In the last decade, the aquatic eddy correlation (EC) technique has proven to be a powerful approach for non-invasive measurements of oxygen fluxes across the sediment water interface. Fundamental to the EC approach is the correlation of turbulent velocity and oxygen concentration fluctuations measured with high frequencies in the same sampling volume. Oxygen concentrations are commonly measured with fast responding electrochemical microsensors. However, due to their own oxygen consumption, electrochemical microsensors are sensitive to changes of the diffusive boundary layer surrounding the probe and thus to changes in the ambient flow velocity. The so-called stirring sensitivity of microsensors constitutes an inherent correlation of flow velocity and oxygen sensing and thus an artificial flux which can confound the benthic flux determination. To assess the artificial flux we measured the correlation between the turbulent flow velocity and the signal of oxygen microsensors in a sealed annular flume without any oxygen sinks and sources. Experiments revealed significant correlations, even for sensors designed to have low stirring sensitivities of ~0.7%. The artificial fluxes depended on ambient flow conditions and, counter intuitively, increased at higher velocities because of the nonlinear contribution of turbulent velocity fluctuations. The measured artificial fluxes ranged from 2 - 70 mmol m-2 d-1 for weak and very strong turbulent flow, respectively. Further, the stirring sensitivity depended on the sensor orientation towards the flow. For a sensor orientation typically used in field studies, the artificial flux could be predicted using a simplified mathematical model. Optical microsensors (optodes) that should not exhibit a stirring sensitivity were tested in parallel and did not show any significant correlation between O2 signals and turbulent flow. In conclusion, EC data obtained with electrochemical sensors can be affected by artificial flux and we recommend using optical microsensors in future EC-studies. PMID:25635679

Challenges and benefits on long-term eddy covariance measurements over lakes

NASA Astrophysics Data System (ADS)

Vesala, Timo; Golub, Malgorzata; Desai, Ankur; Heiskanen, Jouni; Provenzale, Maria; Rantakari, Miitta; Ojala, Anne; Mammarella, Ivan

2017-04-01

Eddy Covariance (EC) data on carbon dioxide fluxes is presently available on about 30 lakes but the time series are mostly short, order of one year. Longer EC series together with chamber measurements and appropriate auxiliary data on water column allow for more accurate estimates of the aquatic component in terrestrial carbon balance and analysis of the environmental controls. We discuss on challenges for long-term EC measurements over freshwater ecosystems and demonstrate the benefits of EC data for carbon cycle studies via examples from long-term sites EC sites in Finland. We discuss on the auxiliary measurements needed and the general design of the whole measurement set-up to get representative information. We discuss on challenges related to the CO2 flux partitioning for freshwater ecosystems and introduce a new method to estimate the net primary productivity (NPP) on EC data, which is superior to more traditional methods (bottle incubations, 14C technique) with a poor temporal resolution. Finally, we collected and analyzed CO2 fluxes from 19 globally distributed lakes and reservoirs representing six climate zones. The mean flux was c. 0.3 micro mole / m2 s. We applied a simple upscaling to the direct observations and ended up to the estimate which is about half of the current emission estimate for lentic systems.

Toxicity of metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb to Phytophthora infestans isolates from Serbia.

PubMed

Rekanović, Emil; Potočnik, Ivana; Milijašević-Marčić, Svetlana; Stepanović, Miloš; Todorović, Biljana; Mihajlović, Milica

2012-01-01

A study of the in vitro sensitivity of 12 isolates of Phytophthora infestans to metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb, was conducted. The isolates derived from infected potato leaves collected at eight different localities in Serbia during 2005-2007. The widest range of EC(50) values for mycelial growth of the isolates was recorded for metalaxyl. They varied from 0.3 to 3.9 μg mL(-1) and were higher than those expected in a susceptible population of P. infestans. The EC(50) values of the isolates were 0.16-0.30 μg mL(-1) for dimethomorph, 0.27-0.57 μg mL(-1) for cymoxanil, 0.0026-0.0049 μg mL(-1) for zoxamide and 2.9-5.0 μg mL(-1) for mancozeb. The results indicated that according to effective concentration (EC(50)) the 12 isolates of P. infestans were sensitive to azoxystrobin (0.019-0.074 μg mL(-1)), and intermediate resistant to metalaxyl, dimethomorph and cymoxanil. According to resistance factor, all P. infestans isolates were sensitive to dimethomorph, cymoxanil, mancozeb and zoxamide, 58.3% of isolates were sensitive to azoxystrobin and 50% to metalaxyl. Gout's scale indicated that 41.7% isolates were moderately sensitive to azoxystrobin and 50% to metalaxyl.

Assessment of metal sensitizer potency with the reconstructed human epidermis IL-18 assay.

PubMed

Gibbs, Susan; Kosten, Ilona; Veldhuizen, Rosalien; Spiekstra, Sander; Corsini, Emanuela; Roggen, Erwin; Rustemeyer, Thomas; Feilzer, Albert J; Kleverlaan, Cees J

2018-01-15

According to the new EU Medical Devices (MDR) legislation coming into effect in 2017, manufactures will have to comply with higher standards of quality and safety for medical devices in order to meet common safety concerns regarding such products. Metal alloys are extensively used in dentistry and medicine (e.g. orthopedic surgery and cardiology) even though clinical experience suggests that many metals are sensitizers. The aim of this study was to further test the applicability domain of the in vitro reconstructed human epidermis (RhE) IL-18 assay developed to identify contact allergens and in doing so: i) determine whether different metal salts, representing leachables from metal alloys used in medical devices, could be correctly labelled and classified; and ii) assess the ability of different salts for the same metal to penetrate the skin stratum corneum. Twenty eight chemicals including 15 metal salts were topically exposed to RhE. Nickel, chrome, gold, palladium were each tested in two different salt forms, and titanium in 4 different salt forms. Metal salts were labelled (YES/NO) as sensitizer if a threshold of more than 5 fold IL18 release was reached. The in vitro estimation of expected sensitization induction level (potency) was assessed by interpolating in vitro EC50 and IL-18 SI2 with LLNA EC3 and human NOEL values from standard reference curves generated using DNCB (extreme) and benzocaine (weak). Metal salts, in contrast to other chemical sensitizers and with the exception of potassium dichromate (VI) and cobalt (II) chloride, were not identified as contact allergens since they only induced a small or no increase in IL-18 production. This finding was not related to a lack of stratum corneum skin penetration since EC50 values (decrease in metabolic activity; MTT assay) were obtained after topical RhE exposure to 8 of the 15 metal salts. For nickel, gold and palladium salts, differences in EC50 values between two salts for the same metal could not be attributed to differences in molarity or valency. For chrome salts the difference in EC50 values may be explained by different valencies (VI vs. III), but not by molarity. In general, metal salts were classified as weaker sensitizers than was indicated from in vivo LLNA EC3 and NOEL data. Our in vitro results show that metals are problematic chemicals to test, in line with the limited number of standardized human and animal studies, which are not currently considered adequate to predict systemic hypersensitivity or autoimmunity, and despite clinical experience, which clearly shows that many metals are indeed a risk to human health. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Inactivation of the Ecs ABC transporter of Staphylococcus aureus attenuates virulence by altering composition and function of bacterial wall.

PubMed

Jonsson, Ing-Marie; Juuti, Jarmo T; François, Patrice; AlMajidi, Rana; Pietiäinen, Milla; Girard, Myriam; Lindholm, Catharina; Saller, Manfred J; Driessen, Arnold J M; Kuusela, Pentti; Bokarewa, Maria; Schrenzel, Jacques; Kontinen, Vesa P

2010-12-02

Ecs is an ATP-binding cassette (ABC) transporter present in aerobic and facultative anaerobic gram-positive Firmicutes. Inactivation of Bacillus subtilis Ecs causes pleiotropic changes in the bacterial phenotype including inhibition of intramembrane proteolysis. The molecule(s) transported by Ecs is (are) still unknown. In this study we mutated the ecsAB operon in two Staphylococcus aureus strains, Newman and LS-1. Phenotypic and functional characterization of these Ecs deficient mutants revealed a defect in growth, increased autolysis and lysostaphin sensitivity, altered composition of cell wall proteins including the precursor form of staphylokinase and an altered bacterial surface texture. DNA microarray analysis indicated that the Ecs deficiency changed expression of the virulence factor regulator protein Rot accompanied by differential expression of membrane transport proteins, particularly ABC transporters and phosphate-specific transport systems, protein A, adhesins and capsular polysaccharide biosynthesis proteins. Virulence of the ecs mutants was studied in a mouse model of hematogenous S. aureus infection. Mice inoculated with the ecs mutant strains developed markedly milder infections than those inoculated with the wild-type strains and had consequently lower mortality, less weight loss, milder arthritis and decreased persistence of staphylococci in the kidneys. The ecs mutants had higher susceptibility to ribosomal antibiotics and plant alkaloids chelerythrine and sanguinarine. Our results show that Ecs is essential for staphylococcal virulence and antimicrobial resistance probably since the transport function of Ecs is essential for the normal structure and function of the cell wall. Thus targeting Ecs may be a new approach in combating staphylococcal infection.

Don't Worry, Be Happy: Endocannabinoids and Cannabis at the Intersection of Stress and Reward.

PubMed

Volkow, Nora D; Hampson, Aidan J; Baler, Ruben D

2017-01-06

Cannabis enables and enhances the subjective sense of well-being by stimulating the endocannabinoid system (ECS), which plays a key role in modulating the response to stress, reward, and their interactions. However, over time, repeated activation of the ECS by cannabis can trigger neuroadaptations that may impair the sensitivity to stress and reward. This effect, in vulnerable individuals, can lead to addiction and other adverse consequences. The recent shift toward legalization of medical or recreational cannabis has renewed interest in investigating the physiological role of the ECS as well as the potential health effects, both adverse and beneficial, of cannabis. Here we review our current understanding of the ECS and its complex physiological roles. We discuss the implications of this understanding vis-á-vis the ECS's modulation of stress and reward and its relevance to mental disorders in which these processes are disrupted (i.e., addiction, depression, posttraumatic stress disorder, schizophrenia), along with the therapeutic potential of strategies to manipulate the ECS for these conditions.

Climate change (elevated CO₂, elevated temperature and moderate drought) triggers the antioxidant enzymes' response of grapevine cv. Tempranillo, avoiding oxidative damage.

PubMed

Salazar-Parra, Carolina; Aguirreolea, Jone; Sánchez-Díaz, Manuel; Irigoyen, Juan José; Morales, Fermín

2012-02-01

Photosynthetic carbon fixation (A(N) ) and photosynthetic electron transport rate (ETR) are affected by different environmental stress factors, such as those associated with climate change. Under stress conditions, it can be generated an electron excess that cannot be consumed, which can react with O₂, producing reactive oxygen species. This work was aimed to evaluate the influence of climate change (elevated CO₂, elevated temperature and moderate drought) on the antioxidant status of grapevine (Vitis vinifera) cv. Tempranillo leaves, from veraison to ripeness. The lowest ratios between electrons generated (ETR) and consumed (A(N) + respiration + photorespiration) were observed in plants treated with elevated CO₂ and elevated temperature. In partially irrigated plants under current ambient conditions, electrons not consumed seemed to be diverted to alternative ways. Oxidative damage to chlorophylls and carotenoids was not observed. However, these plants had increases in thiobarbituric acid reacting substances, an indication of lipid peroxidation. These increases matched well with an early rise of H₂O₂ and antioxidant enzyme activities, superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11) and catalase (EC 1.11.1.6). Enzymatic activities were maintained high until ripeness. In conclusion, plants grown under current ambient conditions and moderate drought were less efficient to cope with oxidative damage than well-irrigated plants, and more interestingly, plants grown under moderate drought but treated with elevated CO₂ and elevated temperature were not affected by oxidative damage, mainly because of higher rates of electrons consumed in photosynthetic carbon fixation. Copyright © Physiologia Plantarum 2011.

Acute sensitivity of the vernal pool fairy shrimp, Branchinecta lynchi (Anostraca; Branchinectidae), and surrogate species to 10 chemicals

USGS Publications Warehouse

Ivey, Chris D.; Besser, John M.; Ingersoll, Christopher G.; Wang, Ning; Rogers, Christopher; Raimondo, Sandy; Bauer, Candice R.; Hammer, Edward J.

2017-01-01

Vernal pool fairy shrimp, Branchinecta lynchi, (Branchiopoda; Anostraca) and other fairy shrimp species have been listed as threatened or endangered under the US Endangered Species Act. Because few data exist about the sensitivity of Branchinecta spp. to toxic effects of contaminants, it is difficult to determine whether they are adequately protected by water quality criteria. A series of acute (24-h) lethality/immobilization tests was conducted with 3 species of fairy shrimp (B. lynchi, Branchinecta lindahli, and Thamnocephalus platyurus) and 10 chemicals with varying modes of toxic action: ammonia, potassium, chloride, sulfate, chromium(VI), copper, nickel, zinc, alachlor, and metolachlor. The same chemicals were tested in 48-h tests with other branchiopods (the cladocerans Daphnia magna and Ceriodaphnia dubia) and an amphipod (Hyalella azteca), and in 96-h tests with snails (Physa gyrina and Lymnaea stagnalis). Median effect concentrations (EC50s) for B. lynchi were strongly correlated (r2 = 0.975) with EC50s for the commercially available fairy shrimp species T. platyurus for most chemicals tested. Comparison of EC50s for fairy shrimp and EC50s for invertebrate taxa tested concurrently and with other published toxicity data indicated that fairy shrimp were relatively sensitive to potassium and several trace metals compared with other invertebrate taxa, although cladocerans, amphipods, and mussels had similar broad toxicant sensitivity. Interspecies correlation estimation models for predicting toxicity to fairy shrimp from surrogate species indicated that models with cladocerans and freshwater mussels as surrogates produced the best predictions of the sensitivity of fairy shrimp to contaminants. The results of these studies indicate that fairy shrimp are relatively sensitive to a range of toxicants, but Endangered Species Act-listed fairy shrimp of the genus Branchinecta were not consistently more sensitive than other fairy shrimp taxa. Environ Toxicol Chem 2017;36:797–806. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Inward rectifier potassium (Kir2.1) channels as end-stage boosters of endothelium-dependent vasodilators.

PubMed

Sonkusare, Swapnil K; Dalsgaard, Thomas; Bonev, Adrian D; Nelson, Mark T

2016-06-15

Increase in endothelial cell (EC) calcium activates calcium-sensitive intermediate and small conductance potassium (IK and SK) channels, thereby causing hyperpolarization and endothelium-dependent vasodilatation. Endothelial cells express inward rectifier potassium (Kir) channels, but their role in endothelium-dependent vasodilatation is not clear. In the mesenteric arteries, only ECs, but not smooth muscle cells, displayed Kir currents that were predominantly mediated by the Kir2.1 isoform. Endothelium-dependent vasodilatations in response to muscarinic receptor, TRPV4 (transient receptor potential vanilloid 4) channel and IK/SK channel agonists were highly attenuated by Kir channel inhibitors and by Kir2.1 channel knockdown. These results point to EC Kir channels as amplifiers of vasodilatation in response to increases in EC calcium and IK/SK channel activation and suggest that EC Kir channels could be targeted to treat endothelial dysfunction, which is a hallmark of vascular disorders. Endothelium-dependent vasodilators, such as acetylcholine, increase intracellular Ca(2+) through activation of transient receptor potential vanilloid 4 (TRPV4) channels in the plasma membrane and inositol trisphosphate receptors in the endoplasmic reticulum, leading to stimulation of Ca(2+) -sensitive intermediate and small conductance K(+) (IK and SK, respectively) channels. Although strong inward rectifier K(+) (Kir) channels have been reported in the native endothelial cells (ECs) their role in EC-dependent vasodilatation is not clear. Here, we test the idea that Kir channels boost the EC-dependent vasodilatation of resistance-sized arteries. We show that ECs, but not smooth muscle cells, of small mesenteric arteries have Kir currents, which are substantially reduced in EC-specific Kir2.1 knockdown (EC-Kir2.1(-/-) ) mice. Elevation of extracellular K(+) to 14 mm caused vasodilatation of pressurized arteries, which was prevented by endothelial denudation and Kir channel inhibitors (Ba(2+) , ML-133) or in the arteries from EC-Kir2.1(-/-) mice. Potassium-induced dilatations were unaffected by inhibitors of TRPV4, IK and SK channels. The Kir channel blocker, Ba(2+) , did not affect currents through TRPV4, IK or SK channels. Endothelial cell-dependent vasodilatations in response to activation of muscarinic receptors, TRPV4 channels or IK/SK channels were reduced, but not eliminated, by Kir channel inhibitors or EC-Kir2.1(-/-) . In angiotensin II-induced hypertension, the Kir channel function was not altered, although the endothelium-dependent vasodilatation was severely impaired. Our results support the concept that EC Kir2 channels boost vasodilatory signals that are generated by Ca(2+) -dependent activation of IK and SK channels. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Differential housing and novelty response: Protection and risk from locomotor sensitization

PubMed Central

Garcia, Erik J.; Haddon, Tara N.; Saucier, Donald A.; Cain, Mary E.

2017-01-01

High novelty seeking increases the risk for drug experimentation and locomotor sensitization. Locomotor sensitization to psychostimulants is thought to reflect neurological adaptations that promote the transition to compulsive drug taking. Rats reared in enrichment (EC) show less locomotor sensitization when compared to rats reared in isolation (IC) or standard conditions (SC). The current research study was designed to test if novelty response contributed locomotor sensitization and more importantly, if the different housing environments could change the novelty response to protect against the development of locomotor sensitization in both adolescence and adulthood. Experiment 1: rats were tested for their response to novelty using the inescapable novelty test (IEN) and pseudorandomly assigned to enriched (EC), isolated (IC), or standard (SC) housing conditions for 30 days. After housing, they were tested with IEN. Rats were then administered amphetamine (0.5 mg/kg) or saline and locomotor activity was measured followed by a sensitization test 14 days later. Experiment 2: rats were tested in the IEN test early adulthood and given five administrations of amphetamine (0.3 mg/kg) or saline and then either stayed in or switched housing environments for 30 days. Rats were then re-tested in the IEN test in late adulthood and administered five more injections of their respective treatments and tested for locomotor sensitization. Results indicate that IC and SC increased the response to novelty. EC housing decreased locomotor response to amphetamine and saline, and SC housing increased the locomotor response to amphetamine. Mediation results indicated that the late adult novelty response fully mediates the locomotor response to amphetamine and saline, while the early adulthood novelty response did not. Conclusions Differential housing changes novelty and amphetamine locomotor response. Novelty response is altered into adulthood and provides evidence that enrichment can be used to reduce drug vulnerability. PMID:28108176

Endoscopic Cerenkov luminescence imaging: in vivo small animal tumor model validation

NASA Astrophysics Data System (ADS)

Song, Tianming; Bao, Chengpeng; Hu, Zhenhua; Wang, Kun; Liu, Xia; Tian, Jie

2015-03-01

Background: Cerenkov luminescence imaging (CLI) provides a great potential for clinical translation of optical molecular imaging techniques through using clinical approved radiotracers. However, it is difficult to obtain the Cerenkov luminescence signal of deeper biological tissues due to the small magnitude of the signal. To efficiently acquire the weak Cerenkov luminescence, we developed an endoscopic Cerenkov luminescence imaging (ECLI) system to reduce the in vivo imaging depth with minimum invasion, and validated the system on small animal tumor models. Methods: For the ECLI system, the laparoscope was connected to a high sensitive charge-couple device (CCD) camera (DU888+, Andor, UK) by a custom made adapter. We conducted a series of in vitro and in vivo experiments by use of the system. In the in vitro experiment, the endoscopic luminescence images of the 18F-FDG with various activities in EP tubes were acquired using ECLI system, and the sensitivity was compared with conventional CLI system. In the in vivo tumor experiment, 18F-FDG with the activity of 200μCi were intravenously injected into 3 tumor mice. Then the ECLI system was used to acquire the optical images for both non-invasive and invasive conditions. Conclusion: Experimental data showed the ECLI system could detect the 18F-FDG with the activity as low as 1μCi. Furthermore, our preliminary results indicated the possibility of ECLI technique for detecting Cerenkov signals inside the tumor tissue with deeper depth and guiding the surgical operation of tumor excision. We believe that this technique can help to accelerate the clinical translation of CLI.

Multi-component intrinsic brain activities as a safe, alternative to cortical stimulation for sensori-motor mapping in neurosurgery.

PubMed

Neshige, Shuichiro; Matsuhashi, Masao; Kobayashi, Katsuya; Sakurai, Takeyo; Shimotake, Akihiro; Hitomi, Takefumi; Kikuchi, Takayuki; Yoshida, Kazumichi; Kunieda, Takeharu; Matsumoto, Riki; Takahashi, Ryosuke; Miyamoto, Susumu; Maruyama, Hirofumi; Matsumoto, Masayasu; Ikeda, Akio

2018-06-18

To assess the feasibility of multi-component electrocorticography (ECoG)-based mapping using "wide-spectrum, intrinsic-brain activities" for identifying the primary sensori-motor area (S1-M1) by comparing that using electrical cortical stimulation (ECS). We evaluated 14 epilepsy patients with 1514 subdural electrodes implantation covering the perirolandic cortices at Kyoto University Hospital between 2011 and 2016. We performed multi-component, ECoG-based mapping (band-pass filter, 0.016-300/600 Hz) involving combined analyses of the single components: movement-related cortical potential (<0.5-1 Hz), event-related synchronization (76-200 Hz), and event-related de-synchronization (8-24 Hz) to identify the S1-M1. The feasibility of multi-component mapping was assessed through comparisons with single-component mapping and ECS. Among 54 functional areas evaluation, ECoG-based maps showed significantly higher rate of localization concordances with ECS maps when the three single-component maps were consistent than when those were inconsistent with each other (p < 0.001 in motor, and p = 0.02 in sensory mappings). Multi-component mapping revealed high sensitivity (89-90%) and specificity (94-97%) as compared with ECS. Wide-spectrum, multi-component ECoG-based mapping is feasible, having high sensitivity/specificity relative to ECS. This safe (non-stimulus) mapping strategy, alternative to ECS, would allow clinicians to rule in/out the possibility of brain function prior to resection surgery. Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Conventional and Nuclear Medicine Imaging in Ectopic Cushing's Syndrome: A Systematic Review

PubMed Central

Isidori, Andrea M.; Sbardella, Emilia; Zatelli, Maria Chiara; Boschetti, Mara; Vitale, Giovanni; Colao, Annamaria

2015-01-01

Context: Ectopic Cushing's Syndrome (ECS) can be a diagnostic challenge with the hormonal source difficult to find. This study analyzes the accuracy of imaging studies in ECS localization. Evidence Acquisition: Systematic review of medical literature for ECS case series providing individual patient data on at least one conventional imaging technique (computed tomography [CT]/magnetic resonance imaging) and one of the following: 111In-pentetreotide (OCT), 131I/123I-metaiodobenzylguanidine, 18F-fluoro-2-deoxyglucose-positron emission tomography (FDG-PET), 18F-fluorodopa-PET (F-DOPA-PET), 68Ga-DOTATATE-PET/CT or 68Ga-DOTATOC-PET/CT scan (68Gallium-SSTR-PET/CT). Evidence Summary: The analysis comprised 231 patients (females, 50.2%; age, 42.6 ± 17 y). Overall, 52.4% (121/231) had “overt” ECS, 18.6% had “occult” ECS, and 29% had “covert” ECS. Tumors were located in the lung (55.3%), mediastinum-thymus (7.9%), pancreas (8.5%), adrenal glands (6.4%), gastrointestinal tract (5.4%), thyroid (3.7%), and other sites (12.8%), and primary tumors were mostly bronchial neuroendocrine tumors (NETs) (54.8%), pancreatic NETs (8%), mediastinum-thymus NETs (6.9%), gastrointestinal NETs (5.3%), pheochromocytoma (6.4%), neuroblastoma (3.2%), and medullary thyroid carcinoma (3.2%). Tumors were localized by CT in 66.2% (137/207), magnetic resonance imaging in 51.5% (53/103), OCT in 48.9% (84/172), FDG-PET in 51.7% (46/89), F-DOPA-PET in 57.1% (12/21), 131/123I-metaiodobenzylguanidine in 30.8% (4/13), and 68Gallium-SSTR-PET/CT in 81.8% (18/22) of cases. Molecular imaging discovered 79.1% (53/67) of tumors unidentified by conventional radiology, with OCT the most commonly used, revealing the tumor in 64%, followed by FDG-PET in 59.4%. F-DOPA-PET was used in only seven covert cases (sensitivity, 85.7%). Notably, 68Gallium-SSTR-PET/CT had 100% sensitivity among covert cases. Conclusions: Nuclear medicine improves the sensitivity of conventional radiology when tumor site identification is problematic. OCT offers a good availability/reliability ratio, and FDG-PET was proven useful. 68Gallium-SSTR-PET/CT use was infrequent, despite offering the highest sensitivity. PMID:26158607

Serum-based six-miRNA signature as a potential marker for EC diagnosis: Comparison with TCGA miRNAseq dataset and identification of miRNA-mRNA target pairs by integrated analysis of TCGA miRNAseq and RNAseq datasets.

PubMed

Sharma, Priyanka; Saraya, Anoop; Sharma, Rinu

2018-01-30

To evaluate the diagnostic potential of a six microRNAs (miRNAs) panel consisting of miR-21, miR-144, miR-107, miR-342, miR-93 and miR-152 for esophageal cancer (EC) detection. The expression of miRNAs was analyzed in EC sera samples using quantitative real-time PCR. Risk score analysis was performed and linear regression models were then fitted to generate the six-miRNA panel. In addition, we made an effort to identify significantly dysregulated miRNAs and mRNAs in EC using the Cancer Genome Atlas (TCGA) miRNAseq and RNAseq datasets, respectively. Further, we identified significantly correlated miRNA-mRNA target pairs by integrating TCGA EC miRNAseq dataset with RNAseq dataset. The panel of circulating miRNAs showed enhanced sensitivity (87.5%) and specificity (90.48%) in terms of discriminating EC patients from normal subjects (area under the curve [AUC] = 0.968). Pathway enrichment analysis for potential targets of six miRNAs revealed 48 significant (P < 0.05) pathways, viz. pathways in cancer, mRNA surveillance, MAPK, Wnt, mTOR signaling, and so on. The expression data for mRNAs and miRNAs, downloaded from TCGA database, lead to identification of 2309 differentially expressed genes and 189 miRNAs. Gene ontology and pathway enrichment analysis showed that cell-cycle processes were most significantly enriched for differentially expressed mRNA. Integrated analysis of TCGA miRNAseq and RNAseq datasets resulted in identification of 53 063 significantly and negatively correlated miRNA-mRNA pairs. In summary, a novel and highly sensitive signature of serum miRNAs was identified for EC detection. Moreover, this is the first report identifying miRNA-mRNA target pairs from EC TCGA dataset, thus providing a comprehensive resource for understanding the interactions existing between miRNA and their target mRNAs in EC. © 2018 John Wiley & Sons Australia, Ltd.

Large-scale estimates of gross primary production on the Qinghai-Tibet plateau based on remote sensing data

NASA Astrophysics Data System (ADS)

Ma, M., II; Yuan, W.; Dong, J.; Zhang, F.; Cai, W.; Li, H.

2017-12-01

Vegetation gross primary production (GPP) is an important variable for the carbon cycle on the Qinghai-Tibetan Plateau (QTP). Based on the measurements from twelve eddy covariance (EC) sites, we validated a light use efficiency model (i.e. EC-LUE) to evaluate the spatial-temporal patterns of GPP and the effect of environmental variables on QTP. The EC-LUE model explained 85.4% of the daily observed GPP variations through all of the twelve EC sites, and characterized very well the seasonal changes of GPP. Annual GPP over the entire QTP ranged from 575 to 703 Tg C, and showed a significantly increasing trend from 1982 to 2013. However, there were large spatial heterogeneities in long-term trends of GPP. Throughout the entire QTP, air temperature TA increase had a greater influence than solar radiation and PREC changes on productivity. Moreover, our results highlight the large uncertainties of previous GPP estimates due to insufficient parameterization and validations. When compared with GPP estimates of the EC-LUE model, most Coupled Model Intercomparison Project (CMIP5) GPP products overestimate the magnitude and increasing trends of regional GPP, which potentially impact the feedback of ecosystems to regional climate changes.

The Extinction and Return of Fear of Public Speaking.

PubMed

Laborda, Mario A; Schofield, Casey A; Johnson, Emily M; Schubert, Jessica R; George-Denn, Daniel; Coles, Meredith E; Miller, Ralph R

2016-11-01

Prior studies indicate extinguished fear often partially returns when participants are later tested outside the extinction context. Cues carried from the extinction context to the test context sometimes reduce return of fear, but it is unclear whether such extinction cues (ECs) reduce return of fear of public speaking. Here we assessed return of fear of public speaking, and whether either of two types of ECs can attenuate it. Participants gave speeches of increasing difficulty during an exposure practice session and were tested 2 days later in a different context. Testing occurred in the presence of physical ECs, after mentally rehearsing the exposure session, or without either reminder. Practice reduced fear of public speaking, but fear partially returned at test. Neither physical nor mental ECs reduced partial return of fear of public speaking. The return of extinguished fear of public speaking, although small, was reliable, but not appreciably sensitive to presence of ECs. © The Author(s) 2016.

Twenty-first century wave climate projections for Ireland and surface winds in the North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Gallagher, Sarah; Gleeson, Emily; Tiron, Roxana; McGrath, Ray; Dias, Frédéric

2016-04-01

Ireland has a highly energetic wave and wind climate, and is therefore uniquely placed in terms of its ocean renewable energy resource. The socio-economic importance of the marine resource to Ireland makes it critical to quantify how the wave and wind climate may change in the future due to global climate change. Projected changes in winds, ocean waves and the frequency and severity of extreme weather events should be carefully assessed for long-term marine and coastal planning. We derived an ensemble of future wave climate projections for Ireland using the EC-Earth global climate model and the WAVEWATCH III® wave model, by comparing the future 30-year period 2070-2099 to the period 1980-2009 for the RCP4.5 and the RCP8.5 forcing scenarios. This dataset is currently the highest resolution wave projection dataset available for Ireland. The EC-Earth ensemble predicts decreases in mean (up to 2 % for RCP4.5 and up to 3.5 % for RCP8.5) 10 m wind speeds over the North Atlantic Ocean (5-75° N, 0-80° W) by the end of the century, which will consequently affect swell generation for the Irish wave climate. The WAVEWATCH III® model predicts an overall decrease in annual and seasonal mean significant wave heights around Ireland, with the largest decreases in summer (up to 15 %) and winter (up to 10 %) for RCP8.5. Projected decreases in mean significant wave heights for spring and autumn were found to be small for both forcing scenarios (less than 5 %), with no significant decrease found for RCP4.5 off the west coast in those seasons.

Effective salt criteria in callus-cultured tomato genotypes.

PubMed

Dogan, Mahmut; Tipirdamaz, Rukiye; Demir, Yavuz

2010-01-01

Na+, Cl-, K+, Ca2+, and proline contents, the rate of lipid peroxidation level in terms of malondialdehyde (MDA) and chlorophyll content, and the changes in the activity of antioxidant enzymes, such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), ascorbate peroxidase (APX: EC 1.11.1.11), and glutathione reductase (GR: EC 1.6.4.2), in tissues of five tomato cultivars in salt tolerance were investigated in a callus culture. The selection of effective parameters used in these tomato genotypes and to find out the use of in vitro tests in place of in vivo salt tolerance tests were investigated. As a material, five different tomato genotypes during a 10-day time period were used, and 150 mM NaCl was applied at callus plant tissue. The exposure to NaCl induced a significant increase in MDA content in both salt-resistant and salt-sensitive cultivars. But the MDA content was higher in salt-sensitive cultivars. The chlorophyll content was more decreased in salt-sensitive than in salt-resistant ones. The proline amount was more increased in salt-sensitive than in salt-resistant ones. It has been reported that salt-tolerant plants, besides being able to regulate the ion and water movements, also exhibit a strong antioxidative enzyme system for effective removal of ROS. The degree of damage depends on the balance between the formation of ROS and its removal by the antioxidative scavenging system that protects against them. Exclusion or inclusion of Na+, Cl-, K+, and Ca2+, antioxidant enzymes and MDA concentration play a key protective role against stress, and this feature at the callus plant tissue used as an identifier for tolerance to salt proved to be an effective criterion.

High-resolution endoscopy plus chromoendoscopy or narrow-band imaging in Barrett's esophagus: a prospective randomized crossover study.

PubMed

Kara, M A; Peters, F P; Rosmolen, W D; Krishnadath, K K; ten Kate, F J; Fockens, P; Bergman, J J G H

2005-10-01

High-resolution endoscopy (HRE) may improve the detection of early neoplasia in Barrett's esophagus. Indigo carmine chromoendoscopy (ICC) and narrow-band imaging (NBI) may be useful techniques to complement HRE. The aim of this study was to compare HRE-ICC with HRE-NBI for the detection of high-grade dysplasia or early cancer (HGD/EC) in patients with Barrett's esophagus. Twenty-eight patients with Barrett's esophagus underwent HRE-ICC and HRE-NBI (separated by 6 - 8 weeks) in a randomized sequence. The two procedures were performed by two different endoscopists, who were blinded to the findings of the other examination. Targeted biopsies were taken from all detected lesions, followed by four-quadrant biopsies at 2-cm intervals. Biopsy evaluation was supervised by a single expert pathologist, who was blinded to the imaging technique used. Fourteen patients were diagnosed with HGD/EC. The sensitivity for HGD/EC was 93 % and 86 % for HRE-ICC and HRE-NBI, respectively. Targeted biopsies had a sensitivity of 79 % with HRE alone. HGD was diagnosed from random biopsies alone in only one patient. ICC and NBI detected a limited number of additional lesions occult to HRE, but these lesions did not alter the sensitivity for identifying patients with HGD/EC. In most patients with high-grade dysplasia or early cancer in Barrett's esophagus, subtle lesions can be identified with high-resolution endoscopy. Indigo carmine chromoendoscopy and narrow-band imaging are comparable as adjuncts to high-resolution endoscopy.

Optimization and field use of a bioassay to monitor sea lice Lepeophtheirus salmonis sensitivity to emamectin benzoate.

PubMed

Westcott, Jillian D; Stryhn, Henrik; Burka, John F; Hammell, K Larry

2008-04-01

A bioassay for sea lice Lepeophtheirus salmonis sensitivity towards emamectin benzoate (EMB) was validated for field use. A probit regression model with natural responsiveness was used for the number of affected (moribund or dead) sea lice in bioassays involving different concentrations of EMB. Bioassay optimization included an evaluation of the inter-rater reliability of sea lice responsiveness to EMB and an evaluation of gender-related differences in susceptibility. Adoption of a set of bioassay response criteria improved the concordance (evaluated using the concordance correlation coefficient) between raters' assessments and the model estimation of EC50 values (the 'effective concentration' leading to a response of 50% of the lice not prone to natural response). An evaluation of gender-related differences in EMB susceptibility indicated that preadult stage female sea lice exhibited a significantly larger sensitivity towards EMB in 12 of 19 bioassays compared to preadult males. In order to evaluate sea lice sensitivity to EMB in eastern Canada, the intensive salmon farming area in the Bay of Fundy in southwestern New Brunswick was divided into 4 distinct regions based on industry health management practices and hydrographics. A total of 38 bioassays were completed from 2002 to 2005 using populations of preadult stage sea lice collected from Atlantic salmon Salmo salar farms within the 4 described regions. There was no significant overall effect of region or year on EC50 values; however, analysis of variance indicated a significant effect of time of year on EC50 values in 2002 and a potential effect in 2004 to 2005. Although the range of EC50 values obtained in this 3 yr study did not appear sufficient to affect current clinical success in the control of sea lice, the results suggest a seasonal- or temperature-associated variation in sensitivity to EMB. This will need to be considered if changes in EMB efficacy occur in the future.

Charge and Geometry of Residues in the Loop 2 β Hairpin Differentially Affect Agonist and Ethanol Sensitivity in Glycine Receptors

PubMed Central

Perkins, Daya I.; Trudell, James R.; Asatryan, Liana; Alkana, Ronald L.

2012-01-01

Recent studies highlighted the importance of loop 2 of α1 glycine receptors (GlyRs) in the propagation of ligand-binding energy to the channel gate. Mutations that changed polarity at position 52 in the β hairpin of loop 2 significantly affected sensitivity to ethanol. The present study extends the investigation to charged residues. We found that substituting alanine with the negative glutamate at position 52 (A52E) significantly left-shifted the glycine concentration response curve and increased sensitivity to ethanol, whereas the negative aspartate substitution (A52D) significantly right-shifted the glycine EC50 but did not affect ethanol sensitivity. It is noteworthy that the uncharged glutamine at position 52 (A52Q) caused only a small right shift of the glycine EC50 while increasing ethanol sensitivity as much as A52E. In contrast, the shorter uncharged asparagine (A52N) caused the greatest right shift of glycine EC50 and reduced ethanol sensitivity to half of wild type. Collectively, these findings suggest that charge interactions determined by the specific geometry of the amino acid at position 52 (e.g., the 1-Å chain length difference between aspartate and glutamate) play differential roles in receptor sensitivity to agonist and ethanol. We interpret these results in terms of a new homology model of GlyR based on a prokaryotic ion channel and propose that these mutations form salt bridges to residues across the β hairpin (A52E-R59 and A52N-D57). We hypothesize that these electrostatic interactions distort loop 2, thereby changing agonist activation and ethanol modulation. This knowledge will help to define the key physical-chemical parameters that cause the actions of ethanol in GlyRs. PMID:22357974

Towards the isolation and estimation of elemental carbon in atmospheric aerosols using supercritical fluid extraction and thermo-optical analysis.

PubMed

Azeem, Hafiz Abdul; Martinsson, Johan; Stenström, Kristina Eriksson; Swietlicki, Erik; Sandahl, Margareta

2017-07-01

Air-starved combustion of biomass and fossil fuels releases aerosols, including airborne carbonaceous particles, causing negative climatic and health effects. Radiocarbon analysis of the elemental carbon (EC) fraction can help apportion sources of its emission, which is greatly constrained by the challenges in isolation of EC from organic compounds in atmospheric aerosols. The isolation of EC using thermo-optical analysis is however biased by the presence of interfering compounds that undergo pyrolysis during the analysis. EC is considered insoluble in all acidic, basic, and organic solvents. Based on the property of insolubility, a sample preparation method using supercritical CO 2 and methanol as co-solvent was developed to remove interfering organic compounds. The efficiency of the method was studied by varying the density of supercritical carbon dioxide by means of temperature and pressure and by varying the methanol content. Supercritical CO 2 with 10% methanol by volume at a temperature of 60 °C, a pressure of 350 bar and 20 min static mode extraction were found to be the most suitable conditions for the removal of 59 ± 3% organic carbon, including compounds responsible for pyrolysis with 78 ± 16% EC recovery. The results indicate that the method has potential for the estimation and isolation of EC from OC for subsequent analysis methods and source apportionment studies.

Vasorelaxant effects of oleamide in rat small mesenteric artery indicate action at a novel cannabinoid receptor.

PubMed

Hoi, Pui Man; Hiley, C Robin

2006-03-01

Oleamide (cis-9-octadecenoamide) exhibits some cannabimimetic responses despite its low affinities at the currently known cannabinoid receptors. Here we have investigated whether or not it is a vasorelaxant in rat small mesenteric arteries. Oleamide elicited vasorelaxation (EC50=1.2+/-0.2 microM, Rmax=99.1+/-3.9%, n=8) which was reduced by endothelial removal. Nitric oxide synthase inhibition reduced the response (EC50=5.3+/-1.6 microM, Rmax=59.2+/-7.7%, n=7; P<0.01) as did blockade of Ca2+-sensitive K+ channels (KCa) with apamin plus charybdotoxin (both 50 nM) (EC50=2.1+/-0.2 microM, Rmax=58.4+/-1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10 microM for 30 min) shifted the oleamide concentration-response curve approximately 30-fold to the right (n=7; P<0.01). Pertussis toxin (400 ng ml-1 for 2 h) caused a two-fold shift in the response curve (EC50=2.2+/-0.4 microM, Rmax=66.8+/-4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3 microM) significantly inhibited relaxation induced by oleamide (EC50=3.5+/-0.3 microM, Rmax=75.1+/-1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1 microM), nor the CB2 antagonist, SR144528 (1 microM), had significant effects. O-1918 (10 microM), a putative antagonist at a novel endothelial cannabinoid receptor (abnormal-cannabidiol site), markedly reduced the relaxation to oleamide (n=7; P<0.01). It is concluded that oleamide responses in the rat isolated small mesenteric artery are partly dependent on the presence of the endothelium, activation of Ca2+-sensitive K+ channels (KC)) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KC) and Gi/o) with anandamide in this vessel. This might be distinct from both of the known cannabinoid receptors and the novel abnormal-cannabidiol site.

Estimating the importance of factors influencing the radon-222 flux from building walls.

PubMed

Girault, Frédéric; Perrier, Frédéric

2012-09-01

Radiation hazard in dwellings is dominated by the contribution of radon-222 released from soil and bedrock, but the contribution of building materials can also be important. Using a simple air mixing model in a 2-story house with an attic and a basement, it is estimated that a significant risk arises when the Wall Radon exhalation Flux (WRF) exceeds 10×10(-3) Bq·m(-2)·s(-1). WRF is studied using a multiphase advection-diffusion 3-layer analytical model with advective flow, possibly induced by a pressure deficit inside the house compared with the outside atmosphere. To first order, in most circumstances, the WRF is proportional to the wall thickness and to the radon source term, the effective radium concentration EC(Ra), which is the product of the radium-226 concentration by the emanation coefficient E. The WRF decreases with increasing material porosity and exhibits a maximum for water saturation of about 50%. For EC(Ra)=10 Bq·kg(-1), in many instances, WRF is larger than 10×10(-3) Bq·m(-2)·s(-1) and, therefore, EC(Ra)=10 Bq·kg(-1) can be considered as the typical limit not to be exceeded by building materials. An upper limit of the WRF is obtained in the purely advective regime, independent of porosity or moisture content, which can thus be used as a robust safety guideline. The sensitivity of WRF to temperature, due to the temperature sensitivity of EC(Ra) or the temperature sensitivity of radon Henry constant can be larger than 5% for the seasonal variation in the presence of slight pressure deficit. The temperature sensitivity of EC(Ra) is the dominant effect, except for moist walls. Temperature and moisture variation effects on the WRF potentially can account for most observed seasonal variations of radon concentration in houses, in addition to seasonal changes of air exchange, suggesting that the contribution of walls should be considered when designing remediation strategies and studied with dedicated experiments. Copyright © 2012 Elsevier B.V. All rights reserved.

Enzyme catalysis-electrophoresis titration for multiplex enzymatic assay via moving reaction boundary chip.

PubMed

Zhong, Ran; Xie, Haiyang; Kong, Fanzhi; Zhang, Qiang; Jahan, Sharmin; Xiao, Hua; Fan, Liuyin; Cao, Chengxi

2016-09-21

In this work, we developed the concept of enzyme catalysis-electrophoresis titration (EC-ET) under ideal conditions, the theory of EC-ET for multiplex enzymatic assay (MEA), and a related method based on a moving reaction boundary (MRB) chip with a collateral channel and cell phone imaging. As a proof of principle, the model enzymes horseradish peroxidase (HRP), laccase and myeloperoxidase (MPO) were chosen for the tests of the EC-ET model. The experiments revealed that the EC-ET model could be achieved via coupling EC with ET within a MRB chip; particularly the MEA analyses of catalysis rate, maximum rate, activity, Km and Kcat could be conducted via a single run of the EC-ET chip, systemically demonstrating the validity of the EC-ET theory. Moreover, the developed method had these merits: (i) two orders of magnitude higher sensitivity than a fluorescence microplate reader, (ii) simplicity and low cost, and (iii) fairly rapid (30 min incubation, 20 s imaging) analysis, fair stability (<5.0% RSD) and accuracy, thus validating the EC-ET method. Finally, the developed EC-ET method was used for the clinical assay of MPO activity in blood samples; the values of MPO activity detected via the EC-ET chip were in agreement with those obtained by a traditional fluorescence microplate reader, indicating the applicability of the EC-ET method. The work opens a window for the development of enzymatic research, enzyme assay, immunoassay, and point-of-care testing as well as titration, one of the oldest methods of analysis, based on a simple chip.

Use of refractometry as a new management tool in AI boar centers for quality assurance of extender preparations.

PubMed

Schulze, M; Rüdiger, K; Jung, M; Grossfeld, R

2015-01-01

A study was performed to see if refractometry can be used as a new quality control tool for boar semen extenders. For this the refractive index and osmolality of BTS extender concentrations (EC) were recorded in 10%-steps from 50% to 150% and 200% of the correct amount. Twelve boar ejaculates were evaluated for semen quality. The refractive index for the correctly prepared extender was 4.6±0.0°Bx, corresponded to 316±16mOsmkg(-1), and correlated highly with osmolality (r=0.99; P<0.001). Total sperm motility with 100% EC differed significantly from ≤70% EC (P<0.001) and 200% EC (P<0.001) on day 1 (d1) and d4, respectively. The percentage of motile spermatozoa in a thermoresistance test on d2 showed a significant drop using ≤70% EC (P=0.047) and ≥140% EC (P=0.004). Secondary apical ridge defects were significantly higher using 50% EC (P<0.001) and ≥150% EC (P=0.032) compared to 100% EC, respectively. An increased number of coiled tails were observed using ≤60% EC (P<0.001). Percentages of spermatozoa with intact membranes on d2 resulted in a significant decrease using 50% EC (P<0.001) and ≥150% EC (P=0.005), respectively. The mean percentage of PI negative spermatozoa with active mitochondria on d2 showed a significant difference using ≤60% EC (P=0.016) and ≥140% EC (P<0.001) compared to 100% EC, respectively. Boar sperm quality is affected by inexact extender preparation. The refractive-index is an indicator of osmolality and may be used to verify semen extender preparation. The sensitivity is sufficient to detect deviations from correct extender preparation before negative effects on sperm quality occur. Copyright © 2014 Elsevier B.V. All rights reserved.

BC measurement activities at the U.S. Environmental Protection Agency

EPA Science Inventory

Black carbon (BC)--sometimes referred to as soot, char, or elemental carbon (EC)--is a refractory form of light-absorbing carbon produced from incomplete combustion. Accurate measurement of BC in combustion source emissions is important for understanding anthropogenic climate for...

Advantage of using CBA/N strain mice in a non-radioisotopic modification of the local lymph node assay.

PubMed

Takeyoshi, Masahiro; Noda, Shuji; Yamasaki, Kanji; Kimber, Ian

2006-01-01

The murine local lymph node assay (LLNA) is currently recognized as a stand-alone test method for determining the skin sensitizing potential of chemicals. It has been incorporated into the official test guidelines published by some authorities, including the OECD. To avoid the use of radioisotopes, efforts have been made recently to develop non-radioisotopic modifications of the LLNA. A non-radioisotopic modification of the LLNA was developed previously using 5-bromo-2'-deoxyuridine (BrdU) incorporation (non-RI LLNA). However, the non-RI LLNA was found to be somewhat less sensitive than the standard assay. This study reports the advantage of using mice of the CBA/N strain in the non-RI LLNA to improve the sensitivity of this method. The non-RI LLNA was performed using CBA/JN and CBA/N mice exposed to one of four confirmed skin sensitizers, 2,4-dinitrochlorobenzene (DNCB), eugenol (EG), isoeugenol (IEG) or alpha-hexylcinnamic aldehyde (HCA), and to one non-sensitizer, propylene glycol (PG). The EC3 values for DNCB, IEG, EG, HCA and PG were calculated to be 0.1%, 9.6%, 40.6%, 45.5% and >50% in CBA/JN mice and 0.08%, 1.9%, 10.7%, 20.3% and >50% in CBA/N mice, respectively. The EC3 values for DNCB, IEG, EG, HCA and PG in the standard LLNA using CBA/Ca mice and radioisotopes were reported elsewhere as being 0.08%, 1.3%, 13.0%, 8.0% and >50%, respectively. The EC3 values derived from the CBA/N mice in the non-RI LLNA were nearly equivalent to the EC3 values obtained using the standard radioisotopic LLNA with CBA/Ca mice. These data suggest that the use of CBA/N mice may provide a realistic opportunity to develop a version of the LLNA that does not have a requirement for the use of radioisotopes, but which nevertheless has sensitivity approaching, or comparable to, the standard method. 2005 John Wiley & Sons, Ltd.

Correlation between experimental human and murine skin sensitization induction thresholds.

PubMed

Api, Anne Marie; Basketter, David; Lalko, Jon

2015-01-01

Quantitative risk assessment for skin sensitization is directed towards the determination of levels of exposure to known sensitizing substances that will avoid the induction of contact allergy in humans. A key component of this work is the predictive identification of relative skin sensitizing potency, achieved normally by the measurement of the threshold (the "EC3" value) in the local lymph node assay (LLNA). In an extended series of studies, the accuracy of this murine induction threshold as the predictor of the absence of a sensitizing effect has been verified by conduct of a human repeated insult patch test (HRIPT). Murine and human thresholds for a diverse set of 57 fragrance chemicals spanning approximately four orders of magnitude variation in potency have been compared. The results confirm that there is a useful correlation, with the LLNA EC3 value helping particularly to identify stronger sensitizers. Good correlation (with half an order of magnitude) was seen with three-quarters of the dataset. The analysis also helps to identify potential outlier types of (fragrance) chemistry, exemplified by hexyl and benzyl salicylates (an over-prediction) and trans-2-hexenal (an under-prediction).

Using the Surface Renewal Technique to Estimate CO2 Exchange from a Rice Field to the Atmosphere

NASA Astrophysics Data System (ADS)

Suvocarev, K.; Reba, M. L.; Runkle, B.

2015-12-01

Measuring CO2 emissions as surface fluxes is crucial for climate change predictions. One major set of techniques to measure surface fluxes is through continuous micrometeorological observations over different landscapes. Recent approaches of the surface renewal method (SR) are becoming important for their capacity to independently measure sensible (H) and latent heat (LE) fluxes while avoiding some of the shortcomings of the eddy covariance method (EC). Unlike EC, SR avoids orientation limitations, leveling requirements and instrumentation separation and shadowing issues. The main advantage of SR over EC method is in its applicability in both roughness and inertial sub-layers. Therefore, SR measurements can be planned in cases where fetch requirements are not adequate for EC application. We applied the recent approach as suggested by Castellvi et al. (2008) over two months (May to July, 2015) of high-frequency data collected by EC equipment from a rice field in Arkansas. The main goal was to extend this SR application to CO2 fluxes (Fc) over agricultural fields. The results show high correlation between EC and SR fluxes (H, LE and Fc) when they are compared for all atmospheric stability conditions (R2 > 0.75). Some overestimation is observed for SR with respect to EC fluxes, similar to the findings of Castellvi et al. (2008) for rangeland grass. For all the data, SR analysis results were about 11%, 18% and 17% higher than the EC results for H, LE and Fc, respectively. These higher flux estimates resulted in better energy balance closure. The root mean square error for Fc was 6.55 μmol m-2 s-1. The observed overestimation will be addressed in the future by using additional methods for the turbulent fluxes quantification.

Investigation of the dermal sensitization potential of various essential oils in the local lymph node assay.

PubMed

Lalko, J; Api, A M

2006-05-01

Essential oils are commonly used fragrance ingredients. The oils themselves are complex mixtures, which may contain naturally occurring contact sensitizers. The local lymph node assay was used to evaluate the dermal sensitization potential of basil, citronella, clove leaf, geranium, litsea cubeba, lemongrass, and palmarosa oils. Three of the major components--citral, eugenol, and geraniol--were included to investigate any difference in sensitization potential arising from their exposure in a mixture. Each fragrance material was tested at five concentration ranging from 2.5% to 50% w/v in 1:3 ethanol:diethyl phthalate. The stimulation index (SI) values were calculated for each dose level, an SI > or = 3 was considered a positive response. The estimated concentration (EC3) required to elicit a positive was calculated and taken as a measure of relative potency. The EC3 values and potency classification for basil, clove leaf, litsea cubeba, lemongrass and palmarosa oils were calculated to be <2.5% (> or = moderate), 7.1% (weak), 8.4% (weak), 6.5% (weak) and 9.6% (weak), respectively. Citronella and geranium oils were negative. The individual components citral, eugenol and geraniol resulted in EC3 values of 6.3%, 5.4% and 11.4%, respectively. In general, the potency of each essential oil did not differ significantly from that observed for its main individual component.

Asynchronous marine-terrestrial signals of the last deglacial warming in East Asia associated with low- and high-latitude climate changes.

PubMed

Xu, Deke; Lu, Houyuan; Wu, Naiqin; Liu, Zhenxia; Li, Tiegang; Shen, Caiming; Wang, Luo

2013-06-11

A high-resolution multiproxy record, including pollen, foraminifera, and alkenone paleothermometry, obtained from a single core (DG9603) from the Okinawa Trough, East China Sea (ECS), provided unambiguous evidence for asynchronous climate change between the land and ocean over the past 40 ka. On land, the deglacial stage was characterized by rapid warming, as reflected by paleovegetation, and it began ca. 15 kaBP, consistent with the timing of the last deglacial warming in Greenland. However, sea surface temperature estimates from foraminifera and alkenone paleothermometry increased around 20-19 kaBP, as in the Western Pacific Warm Pool (WPWP). Sea surface temperatures in the Okinawa Trough were influenced mainly by heat transport from the tropical western Pacific Ocean by the Kuroshio Current, but the epicontinental vegetation of the ECS was influenced by atmospheric circulation linked to the northern high-latitude climate. Asynchronous terrestrial and marine signals of the last deglacial warming in East Asia were thus clearly related to ocean currents and atmospheric circulation. We argue that (i) early warming seawater of the WPWP, driven by low-latitude insolation and trade winds, moved northward via the Kuroshio Current and triggered marine warming along the ECS around 20-19 kaBP similar to that in the WPWP, and (ii) an almost complete shutdown of the Atlantic Meridional Overturning Circulation ca. 18-15 kaBP was associated with cold Heinrich stadial-1 and delayed terrestrial warming during the last deglacial warming until ca. 15 kaBP at northern high latitudes, and hence in East Asia. Terrestrial deglacial warming therefore lagged behind marine changes by ca. 3-4 ka.

Asynchronous marine-terrestrial signals of the last deglacial warming in East Asia associated with low- and high-latitude climate changes

PubMed Central

Xu, Deke; Lu, Houyuan; Wu, Naiqin; Liu, Zhenxia; Li, Tiegang; Shen, Caiming; Wang, Luo

2013-01-01

A high-resolution multiproxy record, including pollen, foraminifera, and alkenone paleothermometry, obtained from a single core (DG9603) from the Okinawa Trough, East China Sea (ECS), provided unambiguous evidence for asynchronous climate change between the land and ocean over the past 40 ka. On land, the deglacial stage was characterized by rapid warming, as reflected by paleovegetation, and it began ca. 15 kaBP, consistent with the timing of the last deglacial warming in Greenland. However, sea surface temperature estimates from foraminifera and alkenone paleothermometry increased around 20–19 kaBP, as in the Western Pacific Warm Pool (WPWP). Sea surface temperatures in the Okinawa Trough were influenced mainly by heat transport from the tropical western Pacific Ocean by the Kuroshio Current, but the epicontinental vegetation of the ECS was influenced by atmospheric circulation linked to the northern high-latitude climate. Asynchronous terrestrial and marine signals of the last deglacial warming in East Asia were thus clearly related to ocean currents and atmospheric circulation. We argue that (i) early warming seawater of the WPWP, driven by low-latitude insolation and trade winds, moved northward via the Kuroshio Current and triggered marine warming along the ECS around 20–19 kaBP similar to that in the WPWP, and (ii) an almost complete shutdown of the Atlantic Meridional Overturning Circulation ca. 18–15 kaBP was associated with cold Heinrich stadial-1 and delayed terrestrial warming during the last deglacial warming until ca. 15 kaBP at northern high latitudes, and hence in East Asia. Terrestrial deglacial warming therefore lagged behind marine changes by ca. 3–4 ka. PMID:23720306

Electrocorticographic language mapping in children by high-gamma synchronization during spontaneous conversation: comparison with conventional electrical cortical stimulation.

PubMed

Arya, Ravindra; Wilson, J Adam; Vannest, Jennifer; Byars, Anna W; Greiner, Hansel M; Buroker, Jason; Fujiwara, Hisako; Mangano, Francesco T; Holland, Katherine D; Horn, Paul S; Crone, Nathan E; Rose, Douglas F

2015-02-01

This study describes development of a novel language mapping approach using high-γ modulation in electrocorticograph (ECoG) during spontaneous conversation, and its comparison with electrical cortical stimulation (ECS) in childhood-onset drug-resistant epilepsy. Patients undergoing invasive pre-surgical monitoring and able to converse with the investigator were eligible. ECoG signals and synchronized audio were acquired during quiet baseline and during natural conversation between investigator and the patient. Using Signal Modeling for Real-time Identification and Event Detection (SIGFRIED) procedure, a statistical model for baseline high-γ (70-116 Hz) power, and a single score for each channel representing the probability that the power features in the experimental signal window belonged to the baseline model, were calculated. Electrodes with significant high-γ responses (HGS) were plotted on the 3D cortical model. Sensitivity, specificity, positive and negative predictive values (PPV, NPV), and classification accuracy were calculated compared to ECS. Seven patients were included (4 males, mean age 10.28 ± 4.07 years). Significant high-γ responses were observed in classic language areas in the left hemisphere plus in some homologous right hemispheric areas. Compared with clinical standard ECS mapping, the sensitivity and specificity of HGS mapping was 88.89% and 63.64%, respectively, and PPV and NPV were 35.29% and 96.25%, with an overall accuracy of 68.24%. HGS mapping was able to correctly determine all ECS+ sites in 6 of 7 patients and all false-sites (ECS+, HGS- for visual naming, n = 3) were attributable to only 1 patient. This study supports the feasibility of language mapping with ECoG HGS during spontaneous conversation, and its accuracy compared to traditional ECS. Given long-standing concerns about ecological validity of ECS mapping of cued language tasks, and difficulties encountered with its use in children, ECoG mapping of spontaneous language may provide a valid alternative for clinical use. Copyright © 2014 Elsevier B.V. All rights reserved.

Do contemporary (1980-2015) emissions determine the elemental carbon deposition trend at Holtedahlfonna glacier, Svalbard?

NASA Astrophysics Data System (ADS)

Ruppel, Meri M.; Soares, Joana; Gallet, Jean-Charles; Isaksson, Elisabeth; Martma, Tõnu; Svensson, Jonas; Kohler, Jack; Pedersen, Christina A.; Manninen, Sirkku; Korhola, Atte; Ström, Johan

2017-10-01

The climate impact of black carbon (BC) is notably amplified in the Arctic by its deposition, which causes albedo decrease and subsequent earlier snow and ice spring melt. To comprehensively assess the climate impact of BC in the Arctic, information on both atmospheric BC concentrations and deposition is essential. Currently, Arctic BC deposition data are very scarce, while atmospheric BC concentrations have been shown to generally decrease since the 1990s. However, a 300-year Svalbard ice core showed a distinct increase in EC (elemental carbon, proxy for BC) deposition from 1970 to 2004 contradicting atmospheric measurements and modelling studies. Here, our objective was to decipher whether this increase has continued in the 21st century and to investigate the drivers of the observed EC deposition trends. For this, a shallow firn core was collected from the same Svalbard glacier, and a regional-to-meso-scale chemical transport model (SILAM) was run from 1980 to 2015. The ice and firn core data indicate peaking EC deposition values at the end of the 1990s and lower values thereafter. The modelled BC deposition results generally support the observed glacier EC variations. However, the ice and firn core results clearly deviate from both measured and modelled atmospheric BC concentration trends, and the modelled BC deposition trend shows variations seemingly independent from BC emission or atmospheric BC concentration trends. Furthermore, according to the model ca. 99 % BC mass is wet-deposited at this Svalbard glacier, indicating that meteorological processes such as precipitation and scavenging efficiency have most likely a stronger influence on the BC deposition trend than BC emission or atmospheric concentration trends. BC emission source sectors contribute differently to the modelled atmospheric BC concentrations and BC deposition, which further supports our conclusion that different processes affect atmospheric BC concentration and deposition trends. Consequently, Arctic BC deposition trends should not directly be inferred based on atmospheric BC measurements, and more observational BC deposition data are required to assess the climate impact of BC in Arctic snow.

Simulating carbon, water and energy fluxes of a rainforest and an oil palm plantation using the Community Land Model (CLM4.5)

NASA Astrophysics Data System (ADS)

Fan, Yuanchao; Bernoux, Martial; Roupsard, Olivier; Panferov, Oleg; Le Maire, Guerric; Tölle, Merja; Knohl, Alexander

2014-05-01

Deforestation and forest degradation driven by the expansion of oil palm (Elaeis guineensis) plantations has become the major source of GHG emission in Indonesia. Changes of land surface properties (e.g. vegetation composition, soil property, surface albedo) associated with rainforest to oil palm conversion might alter the patterns of land-atmosphere energy, water and carbon cycles and therefore affect local or regional climate. Land surface modeling has been widely used to characterize the two-way interactions between climate and human disturbances on land surface. The Community Land Model (CLM) is a third-generation land model that simulates a wide range of biogeophysical and biogeochemical processes. This project utilizes the land-cover/land-use change (LCLUC) capability of the latest CLM versions 4/4.5 to characterize quantitatively how anthropogenic land surface dynamics in Indonesia affect land-atmosphere carbon, water and energy fluxes. Before simulating land use changes, the first objective is to parameterize and validate the CLM model at local rainforest and oil palm plantation sites through separate point simulations. This entails creation and parameterization of a new plant functional type (PFT) for oil palm, as well as sensitivity analysis and adaptation of model parameters for the rainforest PFTs. CLM modelled fluxes for the selected sites are to be compared with field observations from eddy covariance (EC) flux towers (e.g. a rainforest site in Bariri, Sulawesi; an oil palm site in Jambi, Sumatra). After validation, the project will proceed to parameterize land-use transformation system using remote sensing data and to simulate the impacts of historical LUCs on carbon, water and energy fluxes. Last but not least, the effects of future LUCs in Indonesia on the fluxes and carbon sequestration capacity will be investigated through scenario study. Historical land cover changes, especially oil palm coverage, are retrieved from Landsat or MODIS archival images. Oil palm concession boundaries are used to define and project future land use scenarios. Initial results include outputs from a single-point simulation for the Bariri rainforest site forced with locally measured meteorological data which already showed significant advantage over global forcing data in predicting net ecosystem exchange and latent and sensible heat fluxes. Modeled fluxes are being compared with EC flux observations and with Mixfor-SVAT model outputs from another project at the same site. In the next few months, focus will be on sensitivity analyses of model parameters including PFT optical, morphological and physiological parameters that are necessary to configure the new oil palm PFT and represent rainforest to oil palm conversion. The new parameterization will contribute to the development of the CLM model and its implementation in the modelling of LUC effects in tropical regions will help understanding land-climate interactions.

Addressing Water Consumption of Evaporative Coolers with Greywater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahai, Rashmi; Shah, Nihar; Phadke, Amol

Evaporative coolers (ECs) provide significant gains in energy efficiency compared to vapor compression air conditioners, but simultaneously have significant onsite water demand. This can be a major barrier to deployment in areas of the world with hot and arid climates. To address this concern, this study determined where in the world evaporative cooling is suitable, the water consumption of ECs in these cities, and the potential that greywater can be used reduce the consumption of potable water in ECs. ECs covered 69percent of the cities where room air conditioners are may be deployed, based on comfort conditions alone. The averagemore » water consumption due to ECs was found to be 400 L/household/day in the United States and Australia, with the potential for greywater to provide 50percent this amount. In the rest of the world, the average water consumption was 250 L/household/day, with the potential for greywater to supply 80percent of this amount. Home size was the main factor that contributed to this difference. In the Mediterranean, the Middle East, Northern India, and the Midwestern and Southwestern United States alkalinity levels are high and water used for bleeding will likely contribute significantly to EC water consumption. Although technically feasible, upfront costs for household GW systems are currently high. In both developed and developing parts of the world, however, a direct EC and GW system is cost competitive with conventional vapor compression air conditioners. Moreover, in regions of the world that face problems of water scarcity the benefits can substantially outweigh the costs.« less

Predicting ambient aerosol thermal-optical reflectance measurements from infrared spectra: elemental carbon

NASA Astrophysics Data System (ADS)

Dillner, A. M.; Takahama, S.

2015-10-01

Elemental carbon (EC) is an important constituent of atmospheric particulate matter because it absorbs solar radiation influencing climate and visibility and it adversely affects human health. The EC measured by thermal methods such as thermal-optical reflectance (TOR) is operationally defined as the carbon that volatilizes from quartz filter samples at elevated temperatures in the presence of oxygen. Here, methods are presented to accurately predict TOR EC using Fourier transform infrared (FT-IR) absorbance spectra from atmospheric particulate matter collected on polytetrafluoroethylene (PTFE or Teflon) filters. This method is similar to the procedure developed for OC in prior work (Dillner and Takahama, 2015). Transmittance FT-IR analysis is rapid, inexpensive and nondestructive to the PTFE filter samples which are routinely collected for mass and elemental analysis in monitoring networks. FT-IR absorbance spectra are obtained from 794 filter samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to collocated TOR EC measurements. The FT-IR spectra are divided into calibration and test sets. Two calibrations are developed: one developed from uniform distribution of samples across the EC mass range (Uniform EC) and one developed from a uniform distribution of Low EC mass samples (EC < 2.4 μg, Low Uniform EC). A hybrid approach which applies the Low EC calibration to Low EC samples and the Uniform EC calibration to all other samples is used to produce predictions for Low EC samples that have mean error on par with parallel TOR EC samples in the same mass range and an estimate of the minimum detection limit (MDL) that is on par with TOR EC MDL. For all samples, this hybrid approach leads to precise and accurate TOR EC predictions by FT-IR as indicated by high coefficient of determination (R2; 0.96), no bias (0.00 μg m-3, a concentration value based on the nominal IMPROVE sample volume of 32.8 m3), low error (0.03 μg m-3) and reasonable normalized error (21 %). These performance metrics can be achieved with various degrees of spectral pretreatment (e.g., including or excluding substrate contributions to the absorbances) and are comparable in precision and accuracy to collocated TOR measurements. Only the normalized error is higher for the FT-IR EC measurements than for collocated TOR. FT-IR spectra are also divided into calibration and test sets by the ratios OC/EC and ammonium/EC to determine the impact of OC and ammonium on EC prediction. We conclude that FT-IR analysis with partial least squares regression is a robust method for accurately predicting TOR EC in IMPROVE network samples, providing complementary information to TOR OC predictions (Dillner and Takahama, 2015) and the organic functional group composition and organic matter estimated previously from the same set of sample spectra (Ruthenburg et al., 2014).

Predicting ambient aerosol Thermal Optical Reflectance (TOR) measurements from infrared spectra: elemental carbon

NASA Astrophysics Data System (ADS)

Dillner, A. M.; Takahama, S.

2015-06-01

Elemental carbon (EC) is an important constituent of atmospheric particulate matter because it absorbs solar radiation influencing climate and visibility and it adversely affects human health. The EC measured by thermal methods such as Thermal-Optical Reflectance (TOR) is operationally defined as the carbon that volatilizes from quartz filter samples at elevated temperatures in the presence of oxygen. Here, methods are presented to accurately predict TOR EC using Fourier Transform Infrared (FT-IR) absorbance spectra from atmospheric particulate matter collected on polytetrafluoroethylene (PTFE or Teflon) filters. This method is similar to the procedure tested and developed for OC in prior work (Dillner and Takahama, 2015). Transmittance FT-IR analysis is rapid, inexpensive, and non-destructive to the PTFE filter samples which are routinely collected for mass and elemental analysis in monitoring networks. FT-IR absorbance spectra are obtained from 794 filter samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to collocated TOR EC measurements. The FTIR spectra are divided into calibration and test sets. Two calibrations are developed, one which is developed from uniform distribution of samples across the EC mass range (Uniform EC) and one developed from a~uniform distribution of low EC mass samples (EC < 2.4 μg, Low Uniform EC). A hybrid approach which applies the low EC calibration to low EC samples and the Uniform EC calibration to all other samples is used to produces predictions for low EC samples that have mean error on par with parallel TOR EC samples in the same mass range and an estimate of the minimum detection limit (MDL) that is on par with TOR EC MDL. For all samples, this hybrid approach leads to precise and accurate TOR EC predictions by FT-IR as indicated by high coefficient of variation (R2; 0.96), no bias (0.00 μg m-3, concentration value based on the nominal IMPROVE sample volume of 32.8 m-3), low error (0.03 μg m-3) and reasonable normalized error (21 %). These performance metrics can be achieved with various degrees of spectral pretreatment (e.g., including or excluding substrate contributions to the absorbances) and are comparable in precision and accuracy to collocated TOR measurements. Only the normalized error is higher for the FT-IR EC measurements than for collocated TOR. FT-IR spectra are also divided into calibration and test sets by the ratios OC/EC and ammonium/EC to determine the impact of OC and ammonium on EC prediction. We conclude that FT-IR analysis with partial least squares regression is a robust method for accurately predicting TOR EC in IMPROVE network samples; providing complementary information to TOR OC predictions (Dillner and Takahama, 2015) and the organic functional group composition and organic matter (OM) estimated previously from the same set of sample spectra (Ruthenburg et al., 2014).

Source Apportionment of Elemental Carbon in Beijing, China: Insights from Radiocarbon and Organic Marker Measurements.

PubMed

Zhang, Yan-Lin; Schnelle-Kreis, Jürgen; Abbaszade, Gülcin; Zimmermann, Ralf; Zotter, Peter; Shen, Rong-rong; Schäfer, Klaus; Shao, Longyi; Prévôt, André S H; Szidat, Sönke

2015-07-21

Elemental carbon (EC) or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In this study, radiocarbon ((14)C) based source apportionment is used to distinguish between fossil fuel and biomass burning sources of EC isolated from aerosol filter samples collected in Beijing from June 2010 to May 2011. The (14)C results demonstrate that EC is consistently dominated by fossil-fuel combustion throughout the whole year with a mean contribution of 79% ± 6% (ranging from 70% to 91%), though EC has a higher mean and peak concentrations in the cold season. The seasonal molecular pattern of hopanes (i.e., a class of organic markers mainly emitted during the combustion of different fossil fuels) indicates that traffic-related emissions are the most important fossil source in the warm period and coal combustion emissions are significantly increased in the cold season. By combining (14)C based source apportionment results and picene (i.e., an organic marker for coal emissions) concentrations, relative contributions from coal (mainly from residential bituminous coal) and vehicle to EC in the cold period were estimated as 25 ± 4% and 50 ± 7%, respectively, whereas the coal combustion contribution was negligible or very small in the warm period.

A Proposal to Localize Fermi GBM GRBs Through Coordinated Scanning of the GBM Error Circle via Optical Telescopes

NASA Technical Reports Server (NTRS)

Ukwatta, T. N.; Linnemann, J. T.; Tollefson, K.; Abeysekara, A. U.; Bhat, P. N.; Sonbas, E.; Gehrels, N.

2011-01-01

We investigate the feasibility of implementing a system that will coordinate ground-based optical telescopes to cover the Fermi GBM Error Circle (EC). The aim of the system is to localize GBM detected GRBs and facilitate multi-wavelength follow-up from space and ground. This system will optimize the observing locations in the GBM EC based on individual telescope location, Field of View (FoV) and sensitivity. The proposed system will coordinate GBM EC scanning by professional as well as amateur astronomers around the world. The results of a Monte Carlo simulation to investigate the feasibility of the project are presented.

Glucose-dependent and Glucose-sensitizing Insulinotropic Effect of Nateglinide: Comparison to Sulfonylureas and Repaglinide

PubMed Central

Wang, Shuya; Dunning, Beth E.

2001-01-01

Nateglinide, a novel D-phenylalanine derivative, stimulates insulin release via closure of KATP channels in pancreatic β-cell, a primary mechanism of action it shares with sulfonylureas (SUs) and repaglinide. This study investigated (1) the influence of ambient glucose levels on the insulinotropic effects of nateglinide, glyburide and repaglinide, and (2) the influence of the antidiabetic agents on glucose-stimulated insulin secretion (GSIS) in vitro from isolated rat islets. The EC50 of nateglinide to stimulate insulin secretion was 14 μM in the presence of 3mM glucose and was reduced by 6-fold in 8mM glucose and by 16-fold in 16mM glucose, indicating a glucose-dependent insulinotropic effect. The actions of glyburide and repaglinide failed to demonstrate such a glucose concentration-dependent sensitization. When tested at fixed and equipotent concentrations (~2x EC50 in the presence of 8mM glucose) nateglinide and repaglinide shifted the EC50s for GSIS to the left by 1.7mM suggesting an enhancement of islet glucose sensitivity, while glimepiride and glyburide caused, respectively, no change and a right shift of the EC50. These data demonstrate that despite a common basic mechanism of action, the insulinotropic effects of different agents can be influenced differentially by ambient glucose and can differentially influence the islet responsiveness to glucose. Further, the present findings suggest that nateglinide may exert a more physiologic effect on insulin secretion than comparator agents and thereby have less propensity to elicit hypoglycemia in vivo. PMID:12369728

PKA catalytic subunit compartmentation regulates contractile and hypertrophic responses to β-adrenergic signaling

PubMed Central

Yang, Jason H.; Polanowska-Grabowska, Renata K.; Smith, Jeffrey S.; Shields, Charles W.; Saucerman, Jeffrey J.

2014-01-01

β-adrenergic signaling is spatiotemporally heterogeneous in the cardiac myocyte, conferring exquisite control to sympathetic stimulation. Such heterogeneity drives the formation of protein kinase A (PKA) signaling microdomains, which regulate Ca2+ handling and contractility. Here, we test the hypothesis that the nucleus independently comprises a PKA signaling microdomain regulating myocyte hypertrophy. Spatially-targeted FRET reporters for PKA activity identified slower PKA activation and lower isoproterenol sensitivity in the nucleus (t50 = 10.60±0.68 min; EC50 = 89.00 nmol/L) than in the cytosol (t50 = 3.71±0.25 min; EC50 = 1.22 nmol/L). These differences were not explained by cAMP or AKAP-based compartmentation. A computational model of cytosolic and nuclear PKA activity was developed and predicted that differences in nuclear PKA dynamics and magnitude are regulated by slow PKA catalytic subunit diffusion, while differences in isoproterenol sensitivity are regulated by nuclear expression of protein kinase inhibitor (PKI). These were validated by FRET and immunofluorescence. The model also predicted differential phosphorylation of PKA substrates regulating cell contractility and hypertrophy. Ca2+ and cell hypertrophy measurements validated these predictions and identified higher isoproterenol sensitivity for contractile enhancements (EC50 = 1.84 nmol/L) over cell hypertrophy (EC50 = 85.88 nmol/L). Over-expression of spatially targeted PKA catalytic subunit to the cytosol or nucleus enhanced contractile and hypertrophic responses, respectively. We conclude that restricted PKA catalytic subunit diffusion is an important PKA compartmentation mechanism and the nucleus comprises a novel PKA signaling microdomain, insulating hypertrophic from contractile β-adrenergic signaling responses. PMID:24225179

Evaluation of bone marrow specimens with acute myelogenous leukemia for CD34, CD15, CD117, and myeloperoxidase.

PubMed

Dunphy, C H; Polski, J M; Evans, H L; Gardner, L J

2001-08-01

Immunophenotyping of bone marrow (BM) specimens with acute myelogenous leukemia (AML) may be performed by flow cytometric (FC) or immunohistochemical (IH) techniques. Some markers (CD34, CD15, and CD117) are available for both techniques. Myeloperoxidase (MPO) analysis may be performed by enzyme cytochemical (EC) or IH techniques. To determine the reliability of these markers and MPO by these techniques, we designed a study to compare the results of analyses of these markers and MPO by FC (CD34, CD15, and CD117), EC (MPO), and IH (CD34, CD15, CD117, and MPO) techniques. Twenty-nine AMLs formed the basis of the study. These AMLs all had been immunophenotyped previously by FC analysis; 27 also had had EC analysis performed. Of the AMLs, 29 had BM core biopsies and 26 had BM clots that could be evaluated. The paraffin blocks of the 29 BM core biopsies and 26 BM clots were stained for CD34, CD117, MPO, and CD15. These results were compared with results by FC analysis (CD34, CD15, and CD117) and EC analysis (MPO). Immunodetection of CD34 expression in AML had a similar sensitivity by FC and IH techniques. Immunodetection of CD15 and CD117 had a higher sensitivity by FC analysis than by IH analysis. Detection of MPO by IH analysis was more sensitive than by EC analysis. There was no correlation of French-American-British (FAB) subtype of AML with CD34 or CD117 expression. Expression of CD15 was associated with AMLs with a monocytic component. Myeloperoxidase reactivity by IH analysis was observed in AMLs originally FAB subtyped as M0. CD34 can be equally detected by FC and IH techniques. CD15 and CD117 are better detected by FC analysis and MPO is better detected by IH analysis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cary, Robert

The purpose of this study was to measure the organic carbon (OC) and elemental carbon (EC) fractions of PM2.5 particulate matter at the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) sampling site for a 6-month period during the summer of 2013. The site is in a rural location remote from any populated areas, so it would be expected to reflect carbon concentration over long-distance transport patterns. During the same period in 2012, a number of prairie fires in Oklahoma and Texas had produced large plumes of smoke particles, but OC andmore » EC particles had not been quantified. In addition, during the summer months, other wild fires, such as forest fires in the Rocky Mountain states and other areas, can produce carbon aerosols that are transported over long distances. Both of these source types would be expected to contain mixtures of both OC and EC.« less

Potentiation of Catechin Gallate-Mediated Sensitization of Staphylococcus aureus to Oxacillin by Nongalloylated Catechins†

PubMed Central

Stapleton, Paul D.; Shah, Saroj; Hara, Yukihiko; Taylor, Peter W.

2006-01-01

(−)−Epicatechin gallate (ECg) and (−)−epigallocatechin gallate (EGCg) reduce oxacillin resistance in mecA-containing strains of Staphylococcus aureus. Their binding to staphylococcal cells is enhanced by the nongalloyl analogues (−)−epicatechin (EC) and (−)−epigallocatechin (EGC). EC and EGC significantly increased the capacity of ECg and EGCg to reduce levels of staphylococcal oxacillin resistance. PMID:16436737

Ca2+ signaling in injured in situ endothelium of rat aorta.

PubMed

Berra-Romani, Roberto; Raqeeb, Abdul; Avelino-Cruz, José Everardo; Moccia, Francesco; Oldani, Amanda; Speroni, Francisco; Taglietti, Vanni; Tanzi, Franco

2008-09-01

The inner wall of excised rat aorta was scraped by a microelectrode and Ca2+ signals were investigated by fluorescence microscopy in endothelial cells (ECs) directly coupled with injured cells. The injury caused an immediate increase in the intracellular Ca2+ concentration ([Ca2+]i), followed by a long-lasting decay phase due to Ca2+ influx from extracellular space. The immediate response was mainly due to activation of purinergic receptors, as shown by the effect of P2X and P2Y receptors agonists and antagonists, such as suramin, alpha,beta-MeATP, MRS-2179 and 2-MeSAMP. Inhibition of store-operated Ca2+ influx did not affect either the peak response or the decay phase. Furthermore, the latter was: (i) insensitive to phospholipase C inhibition, (ii) sensitive to the gap junction blockers, palmitoleic acid, heptanol, octanol and oleamide, and (iii) sensitive to La3+ and Ni2+, but not to Gd3+. Finally, ethidium bromide or Lucifer Yellow did not enter ECs facing the scraped area. These results suggest that endothelium scraping: (i) causes a short-lasting stimulation of healthy ECs by extracellular nucleotides released from damaged cells and (ii) uncouples the hemichannels of the ECs facing the injury site; these hemichannels do not fully close and allow a long-lasting Ca2+ entry.

Impaired calcium sensing distinguishes primary hyperparathyroidism (PHPT) patients with low bone mineral density.

PubMed

Weber, Thomas J; Koh, James; Thomas, Samantha M; Hogue, Joyce A; Scheri, Randall P; Roman, Sanziana A; Sosa, Julie A

2017-09-01

A subset of PHPT patients exhibit a more severe disease phenotype characterized by bone loss, fractures, recurrent nephrolithiasis, and other dysfunctions, but the underlying reasons for this disparity in clinical presentation remain unknown. We sought to identify new mechanistic indices that could inform more personalized management of PHPT. Pre-, peri-, and postoperative data and demographic, clinical, and pathological information from patients undergoing parathyroidectomy for PHPT were collected. Univariate and partial Spearman correlation was used to estimate the association of parathyroid tumor calcium sensing capacity with select variables. An unselected series of 237 patients aged >18years and undergoing parathyroidectomy for PHPT were enrolled. Calcium sensing capacity, expressed as the concentration required for half-maximal biochemical response (EC50), was evaluated in parathyroid tumors from an unselected series of 74 patients and assessed for association with clinical parameters. The hypothesis was that greater disease severity would be associated with attenuated calcium sensitivity and biochemically autonomous parathyroid tumor behavior. Parathyroid tumors segregated into two distinct groups of calcium responsiveness (EC50<3.0 and ≥3.0mM). The low EC50 group (n=27) demonstrated a mean calcium EC50 value of 2.49mM [95% confidence interval (CI): 2.43-2.54mM], consistent with reference normal activity. In contrast, the high EC50 group (n=47) displayed attenuated calcium sensitivity with a mean EC50 value of 3.48mM [95% CI: 3.41-3.55mM]. Retrospective analysis of the clinical registry data suggested that high calcium EC50 patients presented with a more significant preoperative bone mineral density (BMD) deficit with a t-score of -2.7, (95% CI: -3.4 to -1.9) versus 0.9, (95% CI: -2.1 to -0.4) in low EC50 patients (p<0.001). After adjusting for gender, age, BMI, 25 OH vitamin D level and preoperative iPTH, lowest t-score and calcium EC50 were inversely correlated, with a partial Spearman correlation coefficient of -0.35 (p=0.02). Impaired calcium sensing in parathyroid tumors is selectively observed in a subset of patients with more severe bone mineral density deficit. Assessment of parathyroid tumor biochemical behavior may be a useful predictor of disease severity as measured by bone mineral density in patients with PHPT. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute sensitivity of the vernal pool fairy shrimp, Branchinecta lynchi (Anostraca; Branchinectidae), and surrogate species to 10 chemicals.

PubMed

Ivey, Chris D; Besser, John M; Ingersoll, Chris G; Wang, Ning; Rogers, D Christopher; Raimondo, Sandy; Bauer, Candice R; Hammer, Edward J

2017-03-01

Vernal pool fairy shrimp, Branchinecta lynchi, (Branchiopoda; Anostraca) and other fairy shrimp species have been listed as threatened or endangered under the US Endangered Species Act. Because few data exist about the sensitivity of Branchinecta spp. to toxic effects of contaminants, it is difficult to determine whether they are adequately protected by water quality criteria. A series of acute (24-h) lethality/immobilization tests was conducted with 3 species of fairy shrimp (B. lynchi, Branchinecta lindahli, and Thamnocephalus platyurus) and 10 chemicals with varying modes of toxic action: ammonia, potassium, chloride, sulfate, chromium(VI), copper, nickel, zinc, alachlor, and metolachlor. The same chemicals were tested in 48-h tests with other branchiopods (the cladocerans Daphnia magna and Ceriodaphnia dubia) and an amphipod (Hyalella azteca), and in 96-h tests with snails (Physa gyrina and Lymnaea stagnalis). Median effect concentrations (EC50s) for B. lynchi were strongly correlated (r 2  = 0.975) with EC50s for the commercially available fairy shrimp species T. platyurus for most chemicals tested. Comparison of EC50s for fairy shrimp and EC50s for invertebrate taxa tested concurrently and with other published toxicity data indicated that fairy shrimp were relatively sensitive to potassium and several trace metals compared with other invertebrate taxa, although cladocerans, amphipods, and mussels had similar broad toxicant sensitivity. Interspecies correlation estimation models for predicting toxicity to fairy shrimp from surrogate species indicated that models with cladocerans and freshwater mussels as surrogates produced the best predictions of the sensitivity of fairy shrimp to contaminants. The results of these studies indicate that fairy shrimp are relatively sensitive to a range of toxicants, but Endangered Species Act-listed fairy shrimp of the genus Branchinecta were not consistently more sensitive than other fairy shrimp taxa. Environ Toxicol Chem 2017;36:797-806. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Investigation of a new pH-responsive nanoparticulate pore former for controlled release enteric coating with improved processability and stability.

PubMed

Chen, Kuan; Chang, Hao Han R; Shalviri, Alireza; Li, Jason; Lugtu-Pe, Jamie Anne; Kane, Anil; Wu, Xiao Yu

2017-11-01

Water-soluble polymers are often used as pore formers to tailor permeability of film-forming hydrophobic polymers on coated dosage forms. However, their addition to a coating formulation could significantly increase the viscosity thus making the coating process difficult. Moreover, the dissolution of pore formers after oral administration could compromise film integrity resulting in undesirable, inconsistent release profiles. Therefore, a non-leaching, pH-responsive nanoparticulate pore former is proposed herein to preserve film integrity and maintain pH-dependent permeability. Poly(methacrylic acid)-polysorbate 80-grafted-starch terpolymer nanoparticles (TPNs) were incorporated within an ethylcellulose (EC) film (TPN-EC) by casting or spray coating. TPNs at 10%wt (pore former level) only increased viscosity of EC coating suspension slightly while conventional pore formers increased the viscosity by 490-11,700%. Negligible leaching of TPNs led to superior mechanical properties of TPN-EC films compared to Eudragit® L-EC films. As pH increased from 1.2 to 6.8, TPN-EC films with 10% pore former level exhibited an 8-fold higher diltiazem permeability compared to Eudragit® L-EC films. The pH-dependent drug release kinetics of diltiazem HCl beads coated with TPN-EC films was tunable by adjusting the pore former level. These results suggest that the TPNs are promising pH-sensitive nanoparticulate pore formers in EC-coated dosage forms. Copyright © 2017 Elsevier B.V. All rights reserved.

Clinical impact of endometrial cancer stratified by genetic mutational profiles, POLE mutation, and microsatellite instability.

PubMed

Haruma, Tomoko; Nagasaka, Takeshi; Nakamura, Keiichiro; Haraga, Junko; Nyuya, Akihiro; Nishida, Takeshi; Goel, Ajay; Masuyama, Hisashi; Hiramatsu, Yuji

2018-01-01

The molecular characterization of endometrial cancer (EC) can facilitate identification of various tumor subtypes. Although EC patients with POLE mutations reproducibly demonstrate better prognosis, the outcome of patients with microsatellite instability (MSI) remains controversial. This study attempted to interrogate whether genetic stratification of EC can identify distinct subsets with prognostic significance. A cohort of 138 EC patients who underwent surgical resection with curative intent was enrolled. Sanger sequencing was used to evaluate mutations in the POLE and KRAS genes. MSI analysis was performed using four mononucleotide repeat markers and methylation status of the MLH1 promoter was measured by a fluorescent bisulfite polymerase chain reaction (PCR). Protein expression for mismatch repair (MMR) proteins was evaluated by immunohistochemistry (IHC). Extensive hypermethylation of the MLH1 promoter was observed in 69.6% ECs with MLH1 deficiency and 3.5% with MMR proficiency, but in none of the ECs with loss of other MMR genes (P < .0001). MSI-positive and POLE mutations were found in 29.0% and 8.7% EC patients, respectively. Our MSI analysis showed a sensitivity of 92.7% for EC patients with MMR deficiency, and a specificity of 97.9% for EC patients with MMR proficiency. In univariate and multivariate analyses, POLE mutations and MSI status was significantly associated with progression-free survival (P = 0.0129 and 0.0064, respectively) but not with endometrial cancer-specific survival. This study provides significant evidence that analyses of proofreading POLE mutations and MSI status based on mononucleotide repeat markers are potentially useful biomarkers to identify EC patients with better prognosis.

Putrescine differently influences the effect of salt stress on polyamine metabolism and ethylene synthesis in rice cultivars differing in salt resistance

PubMed Central

Quinet, Muriel; Lefèvre, Isabelle; Lambillotte, Béatrice; Dupont-Gillain, Christine C.; Lutts, Stanley

2010-01-01

Effects of salt stress on polyamine metabolism and ethylene production were examined in two rice (Oryza sativa L.) cultivars [I Kong Pao (IKP), salt sensitive; and Pokkali, salt resistant] grown for 5 d and 12 d in nutrient solution in the presence or absence of putrescine (1 mM) and 0, 50, and 100 mM NaCl. The salt-sensitive (IKP) and salt-resistant (Pokkali) cultivars differ not only in their mean levels of putrescine, but also in the physiological functions assumed by this molecule in stressed tissues. Salt stress increased the proportion of conjugated putrescine in salt-resistant Pokkali and decreased it in the salt-sensitive IKP, suggesting a possible protective function in response to NaCl. Activities of the enzymes ornithine decarboxylase (ODC; EC 4.1.1.17) and arginine decarboxylase (ADC; EC 4.1.1.19) involved in putrescine synthesis were higher in salt-resistant Pokkali than in salt-sensitive IKP. Both enzymes were involved in the response to salt stress. Salt stress also increased diamine oxidase (DAO; 1.4.3.6) and polyamine oxidase (PAO EC 1.5.3.11) activities in the roots of salt-resistant Pokkali and in the shoots of salt-sensitive IKP. Gene expression followed by reverse transcription-PCR suggested that putrescine could have a post-translational impact on genes coding for ADC (ADCa) and ODC (ODCa and ODCb) but could induce a transcriptional activation of genes coding for PAO (PAOb) mainly in the shoot of salt-stressed plants. The salt-resistant cultivar Pokkali produced higher amounts of ethylene than the salt-sensitive cultivar IKP, and exogenous putrescine increased ethylene synthesis in both cultivars, suggesting no direct antagonism between polyamine and ethylene pathways in rice. PMID:20472577

Response of transpiration to rain pulses for two tree species in a semiarid plantation.

PubMed

Chen, Lixin; Zhang, Zhiqiang; Zeppel, Melanie; Liu, Caifeng; Guo, Junting; Zhu, Jinzhao; Zhang, Xuepei; Zhang, Jianjun; Zha, Tonggang

2014-09-01

Responses of transpiration (Ec) to rain pulses are presented for two semiarid tree species in a stand of Pinus tabulaeformis and Robinia pseudoacacia. Our objectives are to investigate (1) the environmental control over the stand transpiration after rainfall by analyzing the effect of vapor pressure deficit (VPD), soil water condition, and rainfall on the post-rainfall Ec development and recovery rate, and (2) the species responses to rain pulses and implications on vegetation coverage under a changing rainfall regime. Results showed that the sensitivity of canopy conductance (Gc) to VPD varied under different incident radiation and soil water conditions, and the two species exhibited the same hydraulic control (-dG c/dlnVPD to Gcref ratio) over transpiration. Strengthened physiological control and low sapwood area of the stand contributed to low Ec. VPD after rainfall significantly influenced the magnitude and time series of post-rainfall stand Ec. The fluctuation of post-rainfall VPD in comparison with the pre-rainfall influenced the Ec recovery. Further, the stand Ec was significantly related to monthly rainfall, but the recovery was independent of the rainfall event size. Ec enhanced with cumulative soil moisture change (ΔVWC) within each dry-wet cycle, yet still was limited in large rainfall months. The two species had different response patterns of post-rainfall Ec recovery. Ec recovery of P. tabulaeformis was influenced by the pre- and post-rainfall VPD differences and the duration of rainless interval. R. pseudoacacia showed a larger immediate post-rainfall Ec increase than P. tabulaeformis did. We, therefore, concluded that concentrated rainfall events do not trigger significant increase of transpiration unless large events penetrate the deep soil and the species differences of Ec in response to pulses of rain may shape the composition of semiarid woodlands under future rainfall regimes.

Development of PCR for screening of enteroaggregative Escherichia coli.

PubMed Central

Schmidt, H; Knop, C; Franke, S; Aleksic, S; Heesemann, J; Karch, H

1995-01-01

In this study, we determined the sequence of the EcoRI-PstI fragment of the plasmid pCVD432, also termed the enteroaggregative Escherichia coli (EAggEC) probe. A primer pair complementary to this probe was designed for PCR amplification of a 630-bp region. Comparison of the analysis of the EAggEC probe sequence with those in database libraries revealed no significant similarity to any known bacterial gene. Pure cultures of E. coli cells, as well as mixed cultures from stool specimens, were investigated with the PCR assay, the EAggEC probe test, and the adherence test. Of 50 E. coli strains which demonstrated aggregative adherence to HEp-2 cells, 43 (86%) were positive with the EAggEC PCR. All 43 of these strains reacted with the EAggEC probe. Six EAggEC strains gave negative results by both molecular techniques. In contrast, only 4 of 418 (0.96%) strains representing other categories of diarrheagenic E. coli demonstrated a positive PCR result. The PCR was also successful in screening for the presence of EAggEC in enriched cultures grown from stool specimens. Compared with cell culture assays and colony hybridization, our findings revealed that the PCR assay was more rapid, simple, and highly sensitive and can therefore be recommended as a screening method for EAggEC in the clinical laboratory. PMID:7751380

A climatology of extratropical cyclones over East Asia during 1958-2001

NASA Astrophysics Data System (ADS)

Zhang, Yingxian; Ding, Yihui; Li, Qiaoping

2012-06-01

A climatology of extratropical cyclones (ECs) over East Asia (20°-75°N, 60°-160°E) is analyzed by applying an improved objective detection and tracking algorithm to the 4-time daily sea level pressure fields from the European Centre for Medium-range Weather Forecasts (ECMWF) reanalysis data. A total of 12914 EC processes for the period of 1958-2001 are identified, with an EC database integrated and EC activities reanalyzed using the objective algorithm. The results reveal that there are three major cyclogenesis regions: West Siberian Plain, Mongolia (to the south of Lake Baikal), and the coastal region of East China; whereas significant cyclolysis regions are observed in Siberia north of 60°N, Northeast China, and Okhotsk Sea-Northwest Pacific. It is found that the EC lifetime is largely 1-7 days while winter ECs have the shortest lifespan. The ECs are the weakest in summer among the four seasons. Strong ECs often appear in West Siberia, Northeast China, and Okhotsk Sea-Northwest Pacific. Statistical analysis based on k-means clustering has identified 6 dominating trajectories in the area south of 55°N and east of 80°E, among which 4 tracks have important impacts on weather/climate in China. ECs occurring in spring (summer) tend to travel the longest (shortest). They move the fastest in winter, and the slowest in summer. In winter, cyclones move fast in Northeast China, some areas of the Yangtze-Huaihe River region, and the south of Japan, with speed greater than 15 m s-1. Explosively-deepening cyclones are found to occur frequently along the east coast of China, Japan, and Northwest Pacific, but very few storms occur over the inland area. Bombs prefer to occur in winter, spring, and autumn. Their annual number and intensity in 1990 and 1992 in East Asia (EA) are smaller and weaker than their counterparts in North America.

Seasonal variability of carbonaceous aerosols in an urban background area in Southern Italy

NASA Astrophysics Data System (ADS)

Cesari, D.; Merico, E.; Dinoi, A.; Marinoni, A.; Bonasoni, P.; Contini, D.

2018-02-01

Organic (OC) and Elemental Carbon (EC) are important components of atmospheric aerosol particles, playing a key role in climate system and potentially affecting human health. There is a lack of data reported for Southern Italy and this work aims to fill this gap, focusing the attention on the long-term trends of OC and EC concentrations in PM2.5 and PM10, and on atmospheric processes and sources influencing seasonal variability. Measurements were taken at the Environmental-Climate Observatory of Lecce (SE Italy, 40°20‧8″N-18°07‧28″E, 37 m a.s.l.), regional station of the Global Atmosphere Watch program (GAW-WMO). Daily PM10 and PM2.5 samples were collected between July 2013 and July 2016. In addition, starting in December 2014, simultaneous equivalent Black Carbon (eBC) concentrations in PM10 were measured using a Multi Angle Absorption Photometer. A subset of 722 PM samples (361 for each size fraction) was analysed by using a thermo-optical method with a Sunset Laboratory OC/EC analyser, to determine elemental and organic carbon concentrations. The average PM10 and PM2.5 concentrations were 28.8 μg/m3 and 17.5 μg/m3. The average OC and EC concentrations in PM10 were 5.4 μg/m3 and 0.8 μg/m3, in PM2.5 these were 4.7 μg/m3 and 0.6 μg/m3. Carbonaceous content was larger during cold season with respect to warm season as well as secondary organic carbon (SOC) that was evaluated using the OC/EC minimum ratio method. SOC was mainly segregated in PM2.5 and represented 53% - 75% of the total OC. A subset of EC data was compared with eBC measurements, showing a good correlation (R2 = 0.80), however, eBC concentrations were higher than EC concentrations of an average factor of 1.95 (+/- 0.55 standard deviation). This could be explained by the presence of a contribution of Brown Carbon (BrC), for example from biomass burning, in eBC measurements. Weekly patterns showed a slight decrease of carbon content during weekends with respect to weekdays especially visible on eBC concentration due to the decrease of road traffic emissions. The daily patterns of hourly eBC concentrations showed a decrease in central diurnal hours, due to the cycle of planetary boundary-layer height, and concentrations peaks during rush hours due to road traffic emissions.

THE LBA PROJECT: NUTRIENT CYCLES AND TRACE GAS EXCHANGE IN SAVANNAS OF CENTRAL BRAZIL

EPA Science Inventory

The Cerrado of central Brazil is one of the largest savannah regions on Earth. The stressors affecting ecosystems in this region, including deforestation, fire, soil degradation, unwise agricultural practices, climate change, and urbanization, are all experienced in many U. S. ec...

Separating sensitivity from exposure in assessing extinction risk from climate change.

PubMed

Dickinson, Maria G; Orme, C David L; Suttle, K Blake; Mace, Georgina M

2014-11-04

Predictive frameworks of climate change extinction risk generally focus on the magnitude of climate change a species is expected to experience and the potential for that species to track suitable climate. A species' risk of extinction from climate change will depend, in part, on the magnitude of climate change the species experiences, its exposure. However, exposure is only one component of risk. A species' risk of extinction will also depend on its intrinsic ability to tolerate changing climate, its sensitivity. We examine exposure and sensitivity individually for two example taxa, terrestrial amphibians and mammals. We examine how these factors are related among species and across regions and how explicit consideration of each component of risk may affect predictions of climate change impacts. We find that species' sensitivities to climate change are not congruent with their exposures. Many highly sensitive species face low exposure to climate change and many highly exposed species are relatively insensitive. Separating sensitivity from exposure reveals patterns in the causes and drivers of species' extinction risk that may not be evident solely from predictions of climate change. Our findings emphasise the importance of explicitly including sensitivity and exposure to climate change in assessments of species' extinction risk.

Separating sensitivity from exposure in assessing extinction risk from climate change

PubMed Central

Dickinson, Maria G.; Orme, C. David L.; Suttle, K. Blake; Mace, Georgina M.

2014-01-01

Predictive frameworks of climate change extinction risk generally focus on the magnitude of climate change a species is expected to experience and the potential for that species to track suitable climate. A species' risk of extinction from climate change will depend, in part, on the magnitude of climate change the species experiences, its exposure. However, exposure is only one component of risk. A species' risk of extinction will also depend on its intrinsic ability to tolerate changing climate, its sensitivity. We examine exposure and sensitivity individually for two example taxa, terrestrial amphibians and mammals. We examine how these factors are related among species and across regions and how explicit consideration of each component of risk may affect predictions of climate change impacts. We find that species' sensitivities to climate change are not congruent with their exposures. Many highly sensitive species face low exposure to climate change and many highly exposed species are relatively insensitive. Separating sensitivity from exposure reveals patterns in the causes and drivers of species' extinction risk that may not be evident solely from predictions of climate change. Our findings emphasise the importance of explicitly including sensitivity and exposure to climate change in assessments of species' extinction risk. PMID:25367429

On the isolation of elemental carbon (EC) for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

NASA Astrophysics Data System (ADS)

Currie, L. A.; Kessler, J. D.

2005-10-01

The primary objective of the research reported here has been the development of a hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of "soot" (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the "truth" was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC) of measurement validity (Currie et al., 2002). Components of the new Hybrid RM (DiesApple), however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves) has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char) from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure.

The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK) and thermal optical transmission (TOT) methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS). As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1) both methods exhibited biomass-C "leakage"; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC) isolated contained about 3% of the original biomass-C.; (2) the initial isothermal oxidation stage of the TOK method substantially reduced the transfer of artifact char to the RC fraction, improving isolation capabilities; (3) the Hybrid RM was not equal to the sum of its parts, with matrix interactions inducing premature loss of EC which, however, could be quantified and minimized; (4) the three-stage TOK method provided a superior capability for carbonate quantification at the sub-micromolar level, with "reagent-free" removal of carbonate-C from EC - essential for low-level EC-14C AMS.

Differential housing and novelty response: Protection and risk from locomotor sensitization.

PubMed

Garcia, Erik J; Haddon, Tara N; Saucier, Donald A; Cain, Mary E

2017-03-01

High novelty seeking increases the risk for drug experimentation and locomotor sensitization. Locomotor sensitization to psychostimulants is thought to reflect neurological adaptations that promote the transition to compulsive drug taking. Rats reared in enrichment (EC) show less locomotor sensitization when compared to rats reared in isolation (IC) or standard conditions (SC). The current research study was designed to test if novelty response contributed locomotor sensitization and more importantly, if the different housing environments could change the novelty response to protect against the development of locomotor sensitization in both adolescence and adulthood. Experiment 1: rats were tested for their response to novelty using the inescapable novelty test (IEN) and pseudorandomly assigned to enriched (EC), isolated (IC), or standard (SC) housing conditions for 30days. After housing, they were tested with IEN. Rats were then administered amphetamine (0.5mg/kg) or saline and locomotor activity was measured followed by a sensitization test 14days later. Experiment 2: rats were tested in the IEN test early adulthood and given five administrations of amphetamine (0.3mg/kg) or saline and then either stayed in or switched housing environments for 30days. Rats were then re-tested in the IEN test in late adulthood and administered five more injections of their respective treatments and tested for locomotor sensitization. Results indicate that IC and SC increased the response to novelty. EC housing decreased locomotor response to amphetamine and saline, and SC housing increased the locomotor response to amphetamine. Mediation results indicated that the late adult novelty response fully mediates the locomotor response to amphetamine and saline, while the early adulthood novelty response did not. Differential housing changes novelty and amphetamine locomotor response. Novelty response is altered into adulthood and provides evidence that enrichment can be used to reduce drug vulnerability. Copyright © 2017 Elsevier Inc. All rights reserved.

How does the sensitivity of climate affect stratospheric solar radiation management?

NASA Astrophysics Data System (ADS)

Ricke, K.; Rowlands, D. J.; Ingram, W.; Keith, D.; Morgan, M. G.

2011-12-01

If implementation of proposals to engineer the climate through solar radiation management (SRM) ever occurs, it is likely to be contingent upon climate sensitivity. Despite this, no modeling studies have examined how the effectiveness of SRM forcings differs between the typical Atmosphere-Ocean General Circulation Models (AOGCMs) with climate sensitivities close to the Coupled Model Intercomparison Project (CMIP) mean and ones with high climate sensitivities. Here, we use a perturbed physics ensemble modeling experiment to examine variations in the response of climate to SRM under different climate sensitivities. When SRM is used as a substitute for mitigation its ability to maintain the current climate state gets worse with increased climate sensitivity and with increased concentrations of greenhouse gases. However, our results also demonstrate that the potential of SRM to slow climate change, even at the regional level, grows with climate sensitivity. On average, SRM reduces regional rates of temperature change by more than 90 percent and rates of precipitation change by more than 50 percent in these higher sensitivity model configurations. To investigate how SRM might behave in models with high climate sensitivity that are also consistent with recent observed climate change we perform a "perturbed physics" ensemble (PPE) modelling experiment with the climateprediction.net (cpdn) version of the HadCM3L AOGCM. Like other perturbed physics climate modelling experiments, we simulate past and future climate scenarios using a wide range of model parameter combinations that both reproduce past climate within a specified level of accuracy and simulate future climates with a wide range of climate sensitivities. We chose 43 members ("model versions") from a subset of the 1,550 from the British Broadcasting Corporation (BBC) climateprediction.net project that have data that allow restarts. We use our results to explore how much assessments of SRM that use best-estimate models, and so near-median climate sensitivity, may be ignoring important contingencies associated with implementing SRM in reality. A primary motivation for studying SRM via the injection of aerosols in the stratosphere is to evaluate its potential effectiveness as "insurance" in the case of higher-than-expected climate response to global warming. We find that this is precisely when SRM appears to be least effective in returning regional climates to their baseline states and reducing regional rates of precipitation change. On the other hand, given the very high regional temperature anomalies associated with rising greenhouse gas concentrations in high sensitivity models, it is also where SRM is most effective in reducing rates of change relative to a no SRM alternative.

What We Have Learned From 20+ Years of Research on Effects of Drought, Fire and Management on Carbon and Water Dynamics of Pacific Northwest Semi-Arid Forests

NASA Astrophysics Data System (ADS)

Law, B. E.; Berner, L. T.; Kwon, H.; Schmidt, A.

2016-12-01

Eco-climatic heterogeneity and proximity to oceans provides endless learning opportunities for eco-physiologists and modelers alike. We have been conducting measurements and modeling of ecosystem responses to climate and disturbance over Oregon's strong climatic gradient since 1990, and in the Metolius semi-arid region. Some of our findings have challenged common assumptions. Our first flux site was the Metolius old-growth ponderosa pine site (established 1996), followed by flux measurements at clusters of different age forests. We found that the old pine site continued to be an annual net carbon sink, contrary to expectations. Twenty years after stand-replacing disturbance, naturally regenerating young ponderosa pine was still a net carbon source, and a young pine plantation with removed debris (lower decomposition) was a weak sink. Physiological sensitivity to climate varies with tree size. Young pine forests responded to seasonal drought sooner and to a more severe degree. During extreme drought years, old pine showed only a small decline in water transport efficiency (11-24%), whereas efficiency declined by 46% in mature pine, and 80% in young pine. Thus, young trees risk hydraulic failure, which may account for higher mortality in young plantations nearby. Carbon uptake (GPP), soil fluxes, and evapotranspiration (calculated from sapflux or eddy flux data) are strongly coupled in the semi-arid ecosystems, suggesting it is feasible to combine sapflux and soil flux data along with water-use efficiency (GPP/LE) from high quality eddy flux data to estimate NEE in the landscape near flux sites or in patches of forests too small for EC measurements. Highlights show our key findings from development and application of multiple models, including SPA, Biome-BGC and CLM, and ideas for future directions.

Acute and chronic toxicity of aluminum to a unionid mussel (Lampsilis siliquoidea) and an amphipod (Hyalella azteca) in water‐only exposures

USGS Publications Warehouse

Wang, Ning; Ivey, Chris D.; Brunson, Eric L.; Cleveland, Danielle; Ingersoll, Christopher G.; Stubblefield, William A.; Cardwell, Allison S.

2018-01-01

The US Environmental Protection Agency (USEPA) is reviewing the protectiveness of the national ambient water quality criteria (WQC) for aluminum (Al) and compiling a toxicity data set to update the WQC. Freshwater mussels are one of the most imperiled groups of animals in the world, but little is known about their sensitivity to Al. The objective of the present study was to evaluate acute 96‐h and chronic 28‐d toxicity of Al to a unionid mussel (Lampsilis siliquoidea) and a commonly tested amphipod (Hyalella azteca) at a pH of 6 and water hardness of 100 mg/L as CaCO3. The acute 50% effect concentration (EC50) for survival of both species was >6200 μg total Al/L. The EC50 was greater than all acute values in the USEPA acute Al data set for freshwater species at a pH range of 5.0 to <6.5 and hardness normalized to 100 mg/L, indicating that the mussel and amphipod were insensitive to Al in acute exposures. The chronic 20% effect concentration (EC20) based on dry weight was 163 μg total Al/L for the mussel and 409 μg total Al/L for the amphipod. Addition of the EC20s to the USEPA chronic Al data set for pH 5.0 to <6.5 would rank the mussel (L. siliquoidea) as the fourth most sensitive species and the amphipod (H. azteca) as the fifth most sensitive species, indicating the 2 species were sensitive to Al in chronic exposures. The USEPA‐proposed acute and chronic WQC for Al would adequately protect the mussel and amphipod tested; however, inclusion of the chronic data from the present study and recalculation of the chronic criterion would likely lower the proposed chronic criterion. 

Temperature sensitivity of ligand-gated ion channels: ryanodine receptor case

NASA Astrophysics Data System (ADS)

Iaparov, B. I.; Moskvin, A. S.; Solovyova, O. E.

2017-11-01

Temperature influences all biochemical processes, in particular, excitation-contraction coupling(ECC) in cardiac cells. In this work we propose a theoretical explanation of temperature effects on an isolated ryanodine receptor calcium release channel (RyR channel) within the electron-conformational (EC) model. We show that the EC model with an Arrhenius-like temperature dependence of the “internal” and “external” frictions and a specific thermosensitivity of the tunnelling “open ↔ closed” transitions can provide both qualitative and quantitative description of the temperature effects for isolated RyR channels. Interestingly that a small change of the activation energy for the “internal” friction can make an ion channel either heat-inhibited or heat-activated while the “external” friction doesn’t play a key role in temperature sensitivity: neglect of “external” friction doesn’t change the channel’s temperature sensitivity qualitatively.

Arrhythmia Evaluation in Wearable ECG Devices

PubMed Central

Sadrawi, Muammar; Lin, Chien-Hung; Hsieh, Yita; Kuo, Chia-Chun; Chien, Jen Chien; Haraikawa, Koichi; Abbod, Maysam F.; Shieh, Jiann-Shing

2017-01-01

This study evaluates four databases from PhysioNet: The American Heart Association database (AHADB), Creighton University Ventricular Tachyarrhythmia database (CUDB), MIT-BIH Arrhythmia database (MITDB), and MIT-BIH Noise Stress Test database (NSTDB). The ANSI/AAMI EC57:2012 is used for the evaluation of the algorithms for the supraventricular ectopic beat (SVEB), ventricular ectopic beat (VEB), atrial fibrillation (AF), and ventricular fibrillation (VF) via the evaluation of the sensitivity, positive predictivity and false positive rate. Sample entropy, fast Fourier transform (FFT), and multilayer perceptron neural network with backpropagation training algorithm are selected for the integrated detection algorithms. For this study, the result for SVEB has some improvements compared to a previous study that also utilized ANSI/AAMI EC57. In further, VEB sensitivity and positive predictivity gross evaluations have greater than 80%, except for the positive predictivity of the NSTDB database. For AF gross evaluation of MITDB database, the results show very good classification, excluding the episode sensitivity. In advanced, for VF gross evaluation, the episode sensitivity and positive predictivity for the AHADB, MITDB, and CUDB, have greater than 80%, except for MITDB episode positive predictivity, which is 75%. The achieved results show that the proposed integrated SVEB, VEB, AF, and VF detection algorithm has an accurate classification according to ANSI/AAMI EC57:2012. In conclusion, the proposed integrated detection algorithm can achieve good accuracy in comparison with other previous studies. Furthermore, more advanced algorithms and hardware devices should be performed in future for arrhythmia detection and evaluation. PMID:29068369

Glyceria maxima as new test species for the EU risk assessment for herbicides: a microcosm study.

PubMed

Mohr, S; Schott, J; Hoenemann, L; Feibicke, M

2015-03-01

In its recent guidance document on tiered risk assessment for plant protection products for aquatic organisms, the European Food Safety Authority (EFSA) proposed to use Glyceria maxima as monocotyledonous grass species for the testing of special herbicide groups. However, published toxicity data for this species is very limited and there is no test guideline for Glyceria sp. For this reason a microcosm study was conducted in order to gain experience on the degree of sensitivity of G. maxima to the herbicidal substances clodinafop-propargyl (grass herbicide) and fluroxypyr (auxin) in comparison to the already established test organism water milfoil Myriophyllum spicatum and the duckweed species Landoltia punctata. Five concentrations without replicates were tested for each test substance using 10 microcosms and three microcosms served as controls. The experiment was run for 8 weeks. Morphological endpoints were used to determine growth and EC50 values. The results show that M. spicatum was most sensitive to fluroxypyr (37 days EC50 for roots: 62 µg/L) and G. maxima most sensitive to clodinafop-propargyl (22 days EC50 for total shoot length: 48 µg/L) whereas the duckweed species was considerable less sensitive. Hence, G. maxima turns out to be a good candidate for testing grass specific herbicides, supporting its inclusion as an additional macrophyte test for the risk assessment of herbicides as proposed by the EFSA.

Functional characterization of sex pheromone receptors in the purple stem borer, Sesamia inferens (Walker).

PubMed

Zhang, Y-N; Zhang, J; Yan, S-W; Chang, H-T; Liu, Y; Wang, G-R; Dong, S-L

2014-10-01

The sex pheromone communication system in moths is highly species-specific and extremely sensitive, and pheromone receptors (PRs) are thought to be the most important factors in males. In the present study, three full-length cDNAs encoding PRs were characterized from Sesamia inferens antennae. These three PRs were all male-specific in expression, but their relative expression levels were very different; SinfOR29 was 17- to 23-fold higher than the other two PRs. Phylogenetic and motif pattern analyses showed that these three PRs were allocated to different PR subfamilies with different motif patterns. Functional analysis using the heterologous expression system of Xenopus oocytes demonstrated that SinfOR29 specifically and sensitively responded to the major pheromone component, Z11-16:OAc [concentration for 50% of maximal effect (EC50 ) = 3.431 × 10(-7) M], while SinfOR21 responded robustly to a minor pheromone component Z11-16:OH (EC50  = 1.087 × 10(-6) M). SinfOR27, however, displayed no response to any of the three pheromone components, but, interestingly, it was sensitive to a non-sex pheromone component Z9,E12-14:OAc (EC50  = 1.522 × 10(-6) M). Our results provide insight into the molecular mechanisms of specificity and sensitivity of the sex pheromone communication system in moths. © 2014 The Royal Entomological Society.

Promoting Writing amongst Peers: Establishing a Community of Writing Practice for Early Career Academics

ERIC Educational Resources Information Center

Kent, Alexandra; Berry, Donna M.; Budds, Kirsty; Skipper, Yvonne; Williams, Helen L.

2017-01-01

In the current research-focused climate, academics are facing increasing pressure to produce research outputs. This pressure can prove particularly daunting for early career (EC) academics, who are simultaneously attempting to master new teaching and administrative demands while establishing their own independent research trajectories. Previous…

Acute toxicity testing with the tropical marine copepod Acartia sinjiensis: optimisation and application.

PubMed

Gissi, F; Binet, M T; Adams, M S

2013-11-01

Globally there is limited toxicity data for tropical marine species, and there has been a call for further research and development in the area of tropical marine ecotoxicology. An increase in developmental pressures in northern tropical Australia is causing a higher demand for toxicity test protocols with ecologically relevant species. Copepods are a diverse group of zooplankton that are major components of marine food webs. The calanoid copepod Acartia sinjiensis is widely distributed across tropical and sub-tropical brackish to marine waters of Australia and was identified in a recent comprehensive review of marine tropical toxicity testing in Australia as a suitable test organism. Through a number of optimisation steps including feeding trials, changes to culture and test conditions; a 48-h acute toxicity test with A. sinjiensis was modified to become a highly reliable and reproducible standard test protocol. Control mobility was improved significantly, and the sensitivity of A. sinjiensis to copper (EC50 of 33µg/L), ammonia (EC50 of 10mg/L) and phenol (EC50 of 13mg/L) fell within the ranges of those reported previously, indicating that the modifications did not alter its sensitivity. In a comprehensive literature search we found that this species was the most sensitive to copper out of a range of marine copepods. The test was also successfully applied in toxicity assessments of four environmental samples: two produced formations waters (PFWs) and two mine tailing liquors (MTLs). The toxicity assessments utilised toxicity data from a suite of marine organisms (bacteria, microalgae, copepods, sea urchins, oysters, prawns, and fish). For the PFWs, which were predominantly contaminated with organic chemicals, A. sinjiensis was the most sensitive species (EC50 value 2-17 times lower than for any other test species). For the predominantly metal-contaminated mine tailing liquors, its sensitivity was similar to that of other test species used. The modified 48-h acute toxicity test with A. sinjiensis proved to be a valuable tool in these toxicity assessments, and is recommended for use in tropical marine toxicity assessments for northern Australia. Copyright © 2013 Elsevier Inc. All rights reserved.

Beyond equilibrium climate sensitivity

NASA Astrophysics Data System (ADS)

Knutti, Reto; Rugenstein, Maria A. A.; Hegerl, Gabriele C.

2017-10-01

Equilibrium climate sensitivity characterizes the Earth's long-term global temperature response to increased atmospheric CO2 concentration. It has reached almost iconic status as the single number that describes how severe climate change will be. The consensus on the 'likely' range for climate sensitivity of 1.5 °C to 4.5 °C today is the same as given by Jule Charney in 1979, but now it is based on quantitative evidence from across the climate system and throughout climate history. The quest to constrain climate sensitivity has revealed important insights into the timescales of the climate system response, natural variability and limitations in observations and climate models, but also concerns about the simple concepts underlying climate sensitivity and radiative forcing, which opens avenues to better understand and constrain the climate response to forcing. Estimates of the transient climate response are better constrained by observed warming and are more relevant for predicting warming over the next decades. Newer metrics relating global warming directly to the total emitted CO2 show that in order to keep warming to within 2 °C, future CO2 emissions have to remain strongly limited, irrespective of climate sensitivity being at the high or low end.

A method for screening climate change-sensitive infectious diseases.

PubMed

Wang, Yunjing; Rao, Yuhan; Wu, Xiaoxu; Zhao, Hainan; Chen, Jin

2015-01-14

Climate change is a significant and emerging threat to human health, especially where infectious diseases are involved. Because of the complex interactions between climate variables and infectious disease components (i.e., pathogen, host and transmission environment), systematically and quantitatively screening for infectious diseases that are sensitive to climate change is still a challenge. To address this challenge, we propose a new statistical indicator, Relative Sensitivity, to identify the difference between the sensitivity of the infectious disease to climate variables for two different climate statuses (i.e., historical climate and present climate) in non-exposure and exposure groups. The case study in Anhui Province, China has demonstrated the effectiveness of this Relative Sensitivity indicator. The application results indicate significant sensitivity of many epidemic infectious diseases to climate change in the form of changing climatic variables, such as temperature, precipitation and absolute humidity. As novel evidence, this research shows that absolute humidity has a critical influence on many observed infectious diseases in Anhui Province, including dysentery, hand, foot and mouth disease, hepatitis A, hemorrhagic fever, typhoid fever, malaria, meningitis, influenza and schistosomiasis. Moreover, some infectious diseases are more sensitive to climate change in rural areas than in urban areas. This insight provides guidance for future health inputs that consider spatial variability in response to climate change.

A Method for Screening Climate Change-Sensitive Infectious Diseases

PubMed Central

Wang, Yunjing; Rao, Yuhan; Wu, Xiaoxu; Zhao, Hainan; Chen, Jin

2015-01-01

Climate change is a significant and emerging threat to human health, especially where infectious diseases are involved. Because of the complex interactions between climate variables and infectious disease components (i.e., pathogen, host and transmission environment), systematically and quantitatively screening for infectious diseases that are sensitive to climate change is still a challenge. To address this challenge, we propose a new statistical indicator, Relative Sensitivity, to identify the difference between the sensitivity of the infectious disease to climate variables for two different climate statuses (i.e., historical climate and present climate) in non-exposure and exposure groups. The case study in Anhui Province, China has demonstrated the effectiveness of this Relative Sensitivity indicator. The application results indicate significant sensitivity of many epidemic infectious diseases to climate change in the form of changing climatic variables, such as temperature, precipitation and absolute humidity. As novel evidence, this research shows that absolute humidity has a critical influence on many observed infectious diseases in Anhui Province, including dysentery, hand, foot and mouth disease, hepatitis A, hemorrhagic fever, typhoid fever, malaria, meningitis, influenza and schistosomiasis. Moreover, some infectious diseases are more sensitive to climate change in rural areas than in urban areas. This insight provides guidance for future health inputs that consider spatial variability in response to climate change. PMID:25594780

Assimilating AmeriFlux Site Data into the Community Land Model with Carbon-Nitrogen Coupling via the Ensemble Kalman Filter

NASA Astrophysics Data System (ADS)

Pettijohn, J. C.; Law, B. E.; Williams, M. D.; Stoeckli, R.; Thornton, P. E.; Hudiburg, T. M.; Thomas, C. K.; Martin, J.; Hill, T. C.

2009-12-01

The assimilation of terrestrial carbon, water and nutrient cycle measurements into land surface models of these processes is fundamental to improving our ability to predict how these ecosystems may respond to climate change. A combination of measurements and models, each with their own systematic biases, must be considered when constraining the nonlinear behavior of these coupled dynamics. As such, we use the sequential Ensemble Kalman Filter (EnKF) to assimilate eddy covariance (EC) and other site-level AmeriFlux measurements into the NCAR Community Land Model with Carbon-Nitrogen coupling (CLM-CN v3.5), run in single-column mode at a 30-minute time step, to improve estimates of relatively unconstrained model state variables and parameters. Specifically, we focus on a semi-arid ponderosa pine site (US-ME2) in the Pacific Northwest to identify the mechanisms by which this ecosystem responds to severe late summer drought. Our EnKF analysis includes water, carbon, energy and nitrogen state variables (e.g., 10 volumetric soil moisture levels (0-3.43 m), ponderosa pine and shrub evapotranspiration and net ecosystem exchange of carbon dioxide stocks and flux components, snow depth, etc.) and associated parameters (e.g., PFT-level rooting distribution parameters, maximum subsurface runoff coefficient, soil hydraulic conductivity decay factor, snow aging parameters, maximum canopy conductance, C:N ratios, etc.). The effectiveness of the EnKF in constraining state variables and associated parameters is sensitive to their relative frequencies, in that C-N state variables and parameters with long time constants require similarly long time series in the analysis. We apply the EnKF kernel perturbation routine to disrupt preliminary convergence of covariances, which has been found in recent studies to be a problem more characteristic of low frequency vegetation state variables and parameters than high frequency ones more heavily coupled with highly varying climate (e.g., shallow soil moisture, snow depth). Preliminary results demonstrate that the assimilation of EC and other available AmeriFlux site physical, chemical and biological data significantly helps quantify and reduce CLM-CN model uncertainties and helps to constrain ‘hidden’ states and parameters that are essential in the coupled water, carbon, energy and nutrient dynamics of these sites. Such site-level calibration of CLM-CN is an initial step in identifying model deficiencies and in forecasts of future ecosystem responses to climate change.

Deep level defects in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Farzana, Esmat; Ahmadi, Elaheh; Speck, James S.; Arehart, Aaron R.; Ringel, Steven A.

2018-04-01

Deep level defects were characterized in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy (PAMBE) using deep level optical spectroscopy (DLOS) and deep level transient (thermal) spectroscopy (DLTS) applied to Ni/β-Ga2O3:Ge (010) Schottky diodes that displayed Schottky barrier heights of 1.50 eV. DLOS revealed states at EC - 2.00 eV, EC - 3.25 eV, and EC - 4.37 eV with concentrations on the order of 1016 cm-3, and a lower concentration level at EC - 1.27 eV. In contrast to these states within the middle and lower parts of the bandgap probed by DLOS, DLTS measurements revealed much lower concentrations of states within the upper bandgap region at EC - 0.1 - 0.2 eV and EC - 0.98 eV. There was no evidence of the commonly observed trap state at ˜EC - 0.82 eV that has been reported to dominate the DLTS spectrum in substrate materials synthesized by melt-based growth methods such as edge defined film fed growth (EFG) and Czochralski methods [Zhang et al., Appl. Phys. Lett. 108, 052105 (2016) and Irmscher et al., J. Appl. Phys. 110, 063720 (2011)]. This strong sensitivity of defect incorporation on crystal growth method and conditions is unsurprising, which for PAMBE-grown β-Ga2O3:Ge manifests as a relatively "clean" upper part of the bandgap. However, the states at ˜EC - 0.98 eV, EC - 2.00 eV, and EC - 4.37 eV are reminiscent of similar findings from these earlier results on EFG-grown materials, suggesting that possible common sources might also be present irrespective of growth method.

Inhomogeneous Forcing and Transient Climate Sensitivity

NASA Technical Reports Server (NTRS)

Shindell, Drew T.

2014-01-01

Understanding climate sensitivity is critical to projecting climate change in response to a given forcing scenario. Recent analyses have suggested that transient climate sensitivity is at the low end of the present model range taking into account the reduced warming rates during the past 10-15 years during which forcing has increased markedly. In contrast, comparisons of modelled feedback processes with observations indicate that the most realistic models have higher sensitivities. Here I analyse results from recent climate modelling intercomparison projects to demonstrate that transient climate sensitivity to historical aerosols and ozone is substantially greater than the transient climate sensitivity to CO2. This enhanced sensitivity is primarily caused by more of the forcing being located at Northern Hemisphere middle to high latitudes where it triggers more rapid land responses and stronger feedbacks. I find that accounting for this enhancement largely reconciles the two sets of results, and I conclude that the lowest end of the range of transient climate response to CO2 in present models and assessments (less than 1.3 C) is very unlikely.

Vasorelaxant effects of oleamide in rat small mesenteric artery indicate action at a novel cannabinoid receptor

PubMed Central

Hoi, Pui Man; Hiley, C Robin

2006-01-01

Oleamide (cis-9-octadecenoamide) exhibits some cannabimimetic responses despite its low affinities at the currently known cannabinoid receptors. Here we have investigated whether or not it is a vasorelaxant in rat small mesenteric arteries. Oleamide elicited vasorelaxation (EC50=1.2±0.2 μM, Rmax=99.1±3.9%, n=8) which was reduced by endothelial removal. Nitric oxide synthase inhibition reduced the response (EC50=5.3±1.6 μM, Rmax=59.2±7.7%, n=7; P<0.01) as did blockade of Ca2+-sensitive K+ channels (KCa) with apamin plus charybdotoxin (both 50 nM) (EC50=2.1±0.2 μM, Rmax=58.4±1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10 μM for 30 min) shifted the oleamide concentration–response curve ∼30-fold to the right (n=7; P<0.01). Pertussis toxin (400 ng ml−1 for 2 h) caused a two-fold shift in the response curve (EC50=2.2±0.4 μM, Rmax=66.8±4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3 μM) significantly inhibited relaxation induced by oleamide (EC50=3.5±0.3 μM, Rmax=75.1±1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1 μM), nor the CB2 antagonist, SR144528 (1 μM), had significant effects. O-1918 (10 μM), a putative antagonist at a novel endothelial cannabinoid receptor (abnormal-cannabidiol site), markedly reduced the relaxation to oleamide (n=7; P<0.01). It is concluded that oleamide responses in the rat isolated small mesenteric artery are partly dependent on the presence of the endothelium, activation of Ca2+-sensitive K+ channels (KCa) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KCa and Gi/o) with anandamide in this vessel. This might be distinct from both of the known cannabinoid receptors and the novel abnormal-cannabidiol site. PMID:16415907

Climate Sensitivity, Sea Level, and Atmospheric Carbon Dioxide

NASA Technical Reports Server (NTRS)

Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

2013-01-01

Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3+/-1deg C for a 4 W/sq m CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3-4deg C for a 4 W/sq m CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.

Proteomic analysis of salt stress and recovery in leaves of Vigna unguiculata cultivars differing in salt tolerance.

PubMed

de Abreu, Carlos Eduardo Braga; Araújo, Gyedre dos Santos; Monteiro-Moreira, Ana Cristina de Oliveira; Costa, José Hélio; Leite, Hugo de Brito; Moreno, Frederico Bruno Mendes Batista; Prisco, José Tarquinio; Gomes-Filho, Enéas

2014-08-01

Cowpea cultivars differing in salt tolerance reveal differences in protein profiles and adopt different strategies to overcome salt stress. Salt-tolerant cultivar shows induction of proteins related to photosynthesis and energy metabolism. Salinity is a major abiotic stress affecting plant cultivation and productivity. The objective of this study was to examine differential proteomic responses to salt stress in leaves of the cowpea cultivars Pitiúba (salt tolerant) and TVu 2331 (salt sensitive). Plants of both cultivars were subjected to salt stress (75 mM NaCl) followed by a recovery period of 5 days. Proteins extracted from leaves of both cultivars were analyzed by two-dimensional electrophoresis (2-DE) under salt stress and after recovery. In total, 22 proteins differentially regulated by both salt and recovery were identified by LC-ESI-MS/MS. Our current proteome data revealed that cowpea cultivars adopted different strategies to overcome salt stress. For the salt-tolerant cultivar (Pitiúba), increase in abundance of proteins involved in photosynthesis and energy metabolism, such as rubisco activase, ribulose-5-phosphate kinase (Ru5PK) (EC 2.7.1.19), glycine decarboxylase (EC 1.4.4.2) and oxygen-evolving enhancer (OEE) protein 2, was observed. However, these vital metabolic processes were more profoundly affected in salt-sensitive cultivar (TVu), as indicated by the down-regulation of OEE protein 1, Mn-stabilizing protein-II, carbonic anhydrase (EC 4.2.1.1) and Rubisco (EC 4.1.1.39), leading to energy reduction and a decline in plant growth. Other proteins differentially regulated in both cultivars corresponded to different physiological responses. Overall, our results provide information that could lead to a better understanding of the molecular basis of salt tolerance and sensitivity in cowpea plants.

Agmatine Induced NO Dependent Rat Mesenteric Artery Relaxation and its Impairment in Salt-Sensitive Hypertension

PubMed Central

Gadkari, Tushar V.; Cortes, Natalie; Madrasi, Kumpal; Tsoukias, Nikolaos M.; Joshi, Mahesh S.

2013-01-01

L-arginine and its decarboxylated product, agmatine are important mediators of NO production and vascular relaxation. However, the underlying mechanisms of their action are not understood. We have investigated the role of arginine and agmatine in resistance vessel relaxation of Sprague-Dawley (SD) and Dahl salt-sensitive hypertensive rats. Second or 3rd-order mesenteric arterioles were cannulated in an organ chamber, pressurized and equilibrated before perfusing intraluminally with agonists. The vessel diameters were measured after mounting on the stage of a microscope fitted with a video camera. The gene expression in Dahl rat vessel homogenates was ascertained by real-time PCR. L-arginine initiated relaxations (EC50, 5.8 ± 0.7 mM; n = 9) were inhibited by arginine decarboxylase (ADC) inhibitor, difluoromethylarginine (DFMA) (EC50, 18.3 ± 1.3 mM; n = 5) suggesting that arginine-induced vessel relaxation was mediated by agmatine formation. Agmatine relaxed the SD rat vessels at significantly lower concentrations (EC50, 138.7 ± 12.1 μM; n = 22), which was compromised by L-NAME (L-NG-Nitroarginine methyl ester, an eNOS inhibitor), RX821002 (α-2 AR antagonist) and pertussis toxin (G-protein inhibitor). The agmatine-mediated vessel relaxation from high salt Dahl rats was abolished as compared to that from normal salt rats (EC50, 143.9 ± 23.4 μM; n = 5). The α-2A AR, α-2B AR and eNOS mRNA expression was downregulated in mesenteric arterioles of high-salt treated Dahl hypertensive rats. These findings demonstrate that agmatine facilitated the relaxation via activation of α-2 adrenergic G-protein coupled receptor and NO synthesis, and this pathway is compromised in salt-sensitive hypertension. PMID:23994446

Agmatine induced NO dependent rat mesenteric artery relaxation and its impairment in salt-sensitive hypertension.

PubMed

Gadkari, Tushar V; Cortes, Natalie; Madrasi, Kumpal; Tsoukias, Nikolaos M; Joshi, Mahesh S

2013-11-30

l-Arginine and its decarboxylated product, agmatine are important mediators of NO production and vascular relaxation. However, the underlying mechanisms of their action are not understood. We have investigated the role of arginine and agmatine in resistance vessel relaxation of Sprague-Dawley (SD) and Dahl salt-sensitive hypertensive rats. Second or 3rd-order mesenteric arterioles were cannulated in an organ chamber, pressurized and equilibrated before perfusing intraluminally with agonists. The vessel diameters were measured after mounting on the stage of a microscope fitted with a video camera. The gene expression in Dahl rat vessel homogenates was ascertained by real-time PCR. l-Arginine initiated relaxations (EC50, 5.8±0.7mM; n=9) were inhibited by arginine decarboxylase (ADC) inhibitor, difluoromethylarginine (DFMA) (EC50, 18.3±1.3mM; n=5) suggesting that arginine-induced vessel relaxation was mediated by agmatine formation. Agmatine relaxed the SD rat vessels at significantly lower concentrations (EC50, 138.7±12.1μM; n=22), which was compromised by l-NAME (l-N(G)-nitroarginine methyl ester, an eNOS inhibitor), RX821002 (α-2 AR antagonist) and pertussis toxin (G-protein inhibitor). The agmatine-mediated vessel relaxation from high salt Dahl rats was abolished as compared to that from normal salt rats (EC50, 143.9±23.4μM; n=5). The α-2A AR, α-2B AR and eNOS mRNA expression was downregulated in mesenteric arterioles of high-salt treated Dahl hypertensive rats. These findings demonstrate that agmatine facilitated the relaxation via activation of α-2 adrenergic G-protein coupled receptor and NO synthesis, and this pathway is compromised in salt-sensitive hypertension. Copyright © 2013 Elsevier Inc. All rights reserved.

N-ω-chloroacetyl-L-ornithine has in-vitro activity against cancer cell lines and in-vivo activity against ascitic and solid tumors.

PubMed

Vargas-Ramírez, Alba L; Medina-Enríquez, Miriam M; Cordero-Rodríguez, Neira I; Ruiz-Cuello, Tatiana; Aguilar-Faisal, Leopoldo; Trujillo-Ferrara, José G; Alcántara-Farfán, Verónica; Rodríguez-Páez, Lorena

2016-07-01

N-ω-chloroacetyl-L-ornithine (NCAO) is an ornithine decarboxylase (ODC) inhibitor that is known to exert cytotoxic and antiproliferative effects on three neoplastic human cancer cell lines (HeLa, MCF-7, and HepG2). Here, we show that NCAO has antiproliferative activity in 13 cancer cell lines, of diverse tissue origin from human and mice, and in a mouse cancer model in vivo. All cell lines were sensitive to NCAO after 72 h of treatment (the EC50 ranged from 1 to 50.6 µmol/l). The Ca Ski cell line was the most sensitive (EC50=1.18±0.07 µmol/l) and MDA-MB-231 was the least sensitive (EC50=50.6±0.3 µmol/l). This ODC inhibitor showed selectivity for cancer cells, exerting almost no cytotoxic effect on the normal Vero cell line (EC50>1000 µmol/l). NCAO induced apoptosis and inhibited tumor cell migration in vitro. Furthermore, in vivo, this compound (at 50 and 100 mg/kg, daily intraperitoneal injection for 7 days) exerted potent antitumor activity against both solid and ascitic tumors in a mouse model using the myeloma (Ag8) cell line. At these same two doses, the toxicological evaluation showed that NCAO has no obvious systemic toxicity. The current results suggest that the antitumor activity is exerted by apoptosis related not only to a local but also a systemic cytotoxic effect exerted by NCAO on tumor cells. The applications for NCAO as an antitumor agent may be extensive; however, further studies are needed to ascertain the antitumor activity on other types of tumor in vivo and to determine the precise molecular mechanism of its activity.

Same Mission, Different Look: Modernizing the AMS DataStreme Project

NASA Astrophysics Data System (ADS)

Abshire, W. E.; Kauffman, C.; Nugnes, K. A.; Geer, I. W.; Mills, E. W.; Stimach, A. E.

2017-12-01

For more than 20 years, the American Meteorological Society (AMS) has been enhancing K-12 teacher preparation and practice, and ultimately student learning through the DataStreme Project. DataStreme Atmosphere, Ocean, and Earth's Climate System (ECS), which are in close alignment with NGSS, empower teachers to implement STEM concepts in their classrooms using real-world data to deepen understanding of core science concepts and raise scientific literacy. For example, DataStreme ECS participants use the AMS Conceptual Climate Energy Model (CCEM) to explore radiative equilibrium. Then, participants use real-world NOAA data within the AMS Climate at a Glance (CAG) app to determine whether or not there is objective evidence consistent with climate change. Both the CCEM and CAG app enable participants to investigate concepts as scientists do, thereby aligning with Dimension 1 of NGSS. This presentation will highlight other ways in which DataStreme ECS aligns with the four disciplinary areas of NGSS. DataStreme courses are offered each fall and spring semester by Local Implementation Teams (LITs) across the country in coordination with AMS Education Program scientists and educators. In 2017, the AMS Education Program entered into a new agreement with California University of Pennsylvania to serve as their institutional partner for DataStreme to offer tuition-free graduate credits to participants. Some changes have already occurred and there are many opportunities for further enhancement. Most noticeably to begin, DataStreme course resources are now available to participants in all 50 states and U.S. territories through a learning management system (LMS). The use of a LMS enables LITs the opportunity to better engage their participants through online discussion boards, video assignments, shared dropbox uploads, digital assessment tools and rubrics, and much more. The Fall 2017 semester was the first term to exploit the Desire to Learn (D2L) platform for course implementation. This presentation will include feedback and lessons learned from early use of new pedagogical tools. The future of teacher professional development opportunities via AMS DataStreme courses is bright as it evolves under new leadership and leverages new tools while staying rooted in its mission to increase public scientific literacy.

Phenological sensitivity to climate across taxa and trophic levels.

PubMed

Thackeray, Stephen J; Henrys, Peter A; Hemming, Deborah; Bell, James R; Botham, Marc S; Burthe, Sarah; Helaouet, Pierre; Johns, David G; Jones, Ian D; Leech, David I; Mackay, Eleanor B; Massimino, Dario; Atkinson, Sian; Bacon, Philip J; Brereton, Tom M; Carvalho, Laurence; Clutton-Brock, Tim H; Duck, Callan; Edwards, Martin; Elliott, J Malcolm; Hall, Stephen J G; Harrington, Richard; Pearce-Higgins, James W; Høye, Toke T; Kruuk, Loeske E B; Pemberton, Josephine M; Sparks, Tim H; Thompson, Paul M; White, Ian; Winfield, Ian J; Wanless, Sarah

2016-07-14

Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5-2.9 days earlier on average), with substantial taxonomic variation (1.1-14.8 days earlier on average).

The Effects of Climate Sensitivity and Carbon Cycle Interactions on Mitigation Policy Stringency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calvin, Katherine V.; Bond-Lamberty, Benjamin; Edmonds, James A.

2015-07-01

Climate sensitivity and climate-carbon cycle feedbacks interact to determine how global carbon and energy cycles will change in the future. While the science of these connections is well documented, their economic implications are not well understood. Here we examine the effect of climate change on the carbon cycle, the uncertainty in climate outcomes inherent in any given policy target, and the economic implications. We examine three policy scenarios—a no policy “Reference” (REF) scenario, and two policies that limit total radiative forcing—with four climate sensitivities using a coupled integrated assessment model. Like previous work, we find that, within a given scenario,more » there is a wide range of temperature change and sea level rise depending on the realized climate sensitivity. We expand on this previous work to show that temperature-related feedbacks on the carbon cycle result in more mitigation required as climate sensitivity increases. Thus, achieving a particular radiative forcing target becomes increasingly expensive as climate sensitivity increases.« less

Adaptive physiological response, carbon partitioning, and biomass production of Withania somnifera (L.) Dunal grown under elevated CO2 regimes.

PubMed

Sharma, Rupali; Singh, Hukum; Kaushik, Monica; Nautiyal, Raman; Singh, Ombir

2018-06-01

Winter cherry or Ashwagandha ( Withania somnifera ) is an important medicinal plant used in traditional and herbal medicine system. Yet, there is no information available on response of this plant to changing climatic conditions particularly elevated atmospheric CO 2 concentrations. Therefore, we conducted an experiment to examine the effect of elevated CO 2 concentrations (ECs) on Withania somnifera . The variations in traits of physiological adaptation, net primary productivity, carbon partitioning, morphology, and biomass in response to elevated CO 2 concentrations (ambient, 600 and 800 µmol mol -1 ) during one growth cycle were investigated within the open top chamber (OTC) facility in the foothill of the Himalayas, Dehardun, India. ECs significantly increased photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, soil respiration, net primary productivity and the carbon content of plant tissues (leaf, stem, and root), and soil carbon. Furthermore, ECs significantly enhanced biomass production (root and shoot), although declined night leaf respiration. Overall, it was summarized that photosynthesis, stomatal conductance, water use efficiency, leaf, and soil carbon and biomass increased under ECs rendering the physiological adaptation to the plant. Increased net primary productivity might facilitate mitigation effects by sequestering elevated levels of carbon dioxide. We advocate further studies to investigate the effects of ECs on the accumulation of secondary metabolites and health-promoting substances of this as well as other medicinal plants.

Electron doping effects on the electrical conductivity of zigzag carbon nanotubes and corresponding unzipped armchair graphene nanoribbons

NASA Astrophysics Data System (ADS)

Mousavi, Hamze; Jalilvand, Samira; Kurdestany, Jamshid Moradi; Grabowski, Marek

2017-10-01

The Kubo formula is used to extract the electrical conductivity (EC) of different diameters of doped zigzag carbon nanotubes and their corresponding unzipped armchair graphene nanoribbons, as a function of temperature and chemical potential, within the tight-binding Hamiltonian model and Green's functions approach. The results reveal more sensitivity to temperature for semiconducting systems in addition to a decrease in EC of all systems with increasing cross-sections.

Development of Ratiometric Fluorescent Biosensors for the Determination of Creatine and Creatinine in Urine.

PubMed

Duong, Hong Dinh; Rhee, Jong Il

2017-11-08

In this study, the oxazine 170 perchlorate (O17)-ethylcellulose (EC) membrane was successfully exploited for the fabrication of creatine- and creatinine-sensing membranes. The sensing membrane exhibited a double layer of O17-EC membrane and a layer of enzyme(s) entrapped in the EC and polyurethane hydrogel (PU) matrix. The sensing principle of the membranes was based on the hydrolytic catalysis of urea, creatine, and creatinine by the enzymes. The reaction end product, ammonia, reacted with O17-EC membrane, resulting in the change in fluorescence intensities at two emission wavelengths ( λ em = 565 and 625 nm). Data collected from the ratio of fluorescence intensities at λ em = 565 and 625 nm were proportional to the concentrations of creatine or creatinine. Creatine- and creatinine-sensing membranes were very sensitive to creatine and creatinine at the concentration range of 0.1-1.0 mM, with a limit of detection (LOD) of 0.015 and 0.0325 mM, respectively. Furthermore, these sensing membranes showed good features in terms of response time, reversibility, and long-term stability. The interference study demonstrated that some components such as amino acids and salts had some negative effects on the analytical performance of the membranes. Thus, the simple and sensitive ratiometric fluorescent sensors provide a simple and comprehensive method for the determination of creatine and creatinine concentrations in urine.

Development of Ratiometric Fluorescent Biosensors for the Determination of Creatine and Creatinine in Urine

PubMed Central

Duong, Hong Dinh; Rhee, Jong Il

2017-01-01

In this study, the oxazine 170 perchlorate (O17)-ethylcellulose (EC) membrane was successfully exploited for the fabrication of creatine- and creatinine-sensing membranes. The sensing membrane exhibited a double layer of O17-EC membrane and a layer of enzyme(s) entrapped in the EC and polyurethane hydrogel (PU) matrix. The sensing principle of the membranes was based on the hydrolytic catalysis of urea, creatine, and creatinine by the enzymes. The reaction end product, ammonia, reacted with O17-EC membrane, resulting in the change in fluorescence intensities at two emission wavelengths (λem = 565 and 625 nm). Data collected from the ratio of fluorescence intensities at λem = 565 and 625 nm were proportional to the concentrations of creatine or creatinine. Creatine- and creatinine-sensing membranes were very sensitive to creatine and creatinine at the concentration range of 0.1–1.0 mM, with a limit of detection (LOD) of 0.015 and 0.0325 mM, respectively. Furthermore, these sensing membranes showed good features in terms of response time, reversibility, and long-term stability. The interference study demonstrated that some components such as amino acids and salts had some negative effects on the analytical performance of the membranes. Thus, the simple and sensitive ratiometric fluorescent sensors provide a simple and comprehensive method for the determination of creatine and creatinine concentrations in urine. PMID:29117119

Mechanical Adaptability of the MMP-Responsive Film Improves the Functionality of Endothelial Cell Monolayer.

PubMed

Hu, Mi; Chang, Hao; Zhang, He; Wang, Jing; Lei, Wen-Xi; Li, Bo-Chao; Ren, Ke-Feng; Ji, Jian

2017-07-01

Extracellular matrix and cells are inherent in coordinating and adapting to each other during all physiological and pathological processes. Synthetic materials, however, show rarely reciprocal and spatiotemporal responses to cells, and lacking self-adapting properties as well. Here, a mechanical adaptability based on the matrix metalloproteinase (MMPs) sensitive polyelectrolyte film is reported. Poly-lysine (PLL) and methacrylated hyaluronic acid (HA-MA) nanolayers are employed to build the thin film through the layer-by-layer assembly, and it is further crosslinked using MMP sensitive peptides, which endows the films with changeable mechanical properties in response to MMPs. It is demonstrated that stiffness of the (PLL/HA-MA) films increases with the crosslinking, and then decreases in response to a treatment of enzyme. Consequently, the crosslinked (PLL/HA-MA) films reveal effective growth of endothelial cells (ECs), leading to fast formation of EC monolayer. Importantly, significantly improved endothelial function of the EC monolayer, which is characterized by integrity, biomolecules release, expression of function related gene, and antithrombotic properties, is achieved along with the decrosslinking of the film because of EC-secreted MMPs. These results suggest that mechanical adaptability of substrate in Young's modulus plays a significant role in endothelial progression, which shows great application potential in tissue engineering, regenerative medicine, and organ-on-a-chip. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of Greenland orography on the Atlantic Meridional Overturning Circulation

NASA Astrophysics Data System (ADS)

Davini, P.; Hardenberg, J.; Filippi, L.; Provenzale, A.

2015-02-01

We show that the absence of the Greenland ice sheet would have important consequences on the North Atlantic Ocean circulation, even without taking into account the effect of the freshwater input to the ocean from ice melting. These effects are investigated in a 600year long coupled ocean-atmosphere simulation with the high-resolution global climate model EC-Earth 3.0.1. Once a new equilibrium is established, a cooling of Eurasia and of the North Atlantic and a poleward shift of the subtropical jet are observed. These hemispheric changes are ascribed to a weakening of the Atlantic Meridional Overturning Circulation (AMOC) by about 12%. We attribute this slowdown to a reduction in salinity of the Arctic basin and to the related change of the mass and salt transport through the Fram Strait—a consequence of the new surface wind pattern over the lower orography. This idealized experiment illustrates the sensitivity of the AMOC to local surface winds.

Toxicity of combined chromium(VI) and phenanthrene pollution on the seed germination, stem lengths, and fresh weights of higher plants.

PubMed

Hu, Shuangqing; Gu, Hairong; Cui, Chunyan; Ji, Rong

2016-08-01

Studies of the interaction and toxicity of pollutant combinations such as heavy metals and PAHs are of practical importance in the remediation and monitoring of the industrial soil environment. This study investigated the single and combined toxicity of chromium(VI) and phenanthrene on three important higher plants: mung beans (Phaseolus aureus), pakchoi cabbage (Brassica chinensis), and rice (Oryza sativa). In experiments using artificial soil matrix, the EC10 and EC20 of the two pollutants, alone and in combination, were analyzed with respect to seed germination, stem length, and above-ground fresh weight of these higher plants. The additive index method was used to evaluate the combined biological toxicity of chromium(VI) and phenanthrene. The results showed that the EC20 of chromium(VI) on the stem lengths of mung beans, pakchoi cabbage, and rice was 289, 248, and 550 mg kg(-1), respectively. The corresponding EC20 values for the fresh weights of the three plants were 334, 307, and 551 mg kg(-1). The EC20 of phenanthrene on the stem lengths of mung beans, pakchoi cabbage, and rice was 528, 426, and 628 mg kg(-1), respectively. The corresponding EC20 values for the fresh weights of the three plants were 696, 585, and 768 mg kg(-1). The EC20 of a combination of chromium(VI) and phenanthrene on the stem lengths of mung beans, pakchoi cabbage, and rice was 192, 173, and 279 mg kg(-1), respectively, and 200, 205, and 271 mg kg(-1) for the fresh weights of the three plants. The single and combined exposure of soil to chromium(VI) and phenanthrene had deleterious effects on plants in the early stage of growth. Overall, pakchoi cabbage was more sensitive than mung beans and rice. The two pollutants exerted synergistic effects on the stem lengths and above-ground fresh weights of both mung beans and rice but antagonistic effects on pakchoi cabbage. The results of this study also suggested pakchoi cabbage as a sensitive indicator of soil pollution.

Comparative analysis of skin sensitization potency of acrylates (methyl acrylate, ethyl acrylate, butyl acrylate, and ethylhexyl acrylate) using the local lymph node assay.

PubMed

Dearman, Rebecca J; Betts, Catherine J; Farr, Craig; McLaughlin, James; Berdasco, Nancy; Wiench, Karin; Kimber, Ian

2007-10-01

There are currently available no systematic experimental data on the skin sensitizing properties of acrylates that are of relevance in occupational settings. Limited information from previous guinea-pig tests or from the local lymph node assay (LLNA) is available; however, these data are incomplete and somewhat contradictory. For those reasons, we have examined in the LLNA 4 acrylates: butyl acrylate (BA), ethyl acrylate (EA), methyl acrylate (MA), and ethylhexyl acrylate (EHA). The LLNA data indicated that all 4 compounds have some potential to cause skin sensitization. In addition, the relative potencies of these acrylates were measured by derivation from LLNA dose-response analyses of EC3 values (the effective concentration of chemical required to induce a threefold increase in proliferation of draining lymph node cells compared with control values). On the basis of 1 scheme for the categorization of skin sensitization potency, BA, EA, and MA were each classified as weak sensitizers. Using the same scheme, EHA was considered a moderate sensitizer. However, it must be emphasized that the EC3 value for this chemical of 9.7% is on the borderline between moderate (<10%) and weak (>10%) categories. Thus, the judicious view is that all 4 chemicals possess relatively weak skin sensitizing potential.

Evanescent wave DNA-aptamer biosensor based on long period gratings for the specific recognition of E. coli outer membrane proteins.

PubMed

Queirós, R B; Gouveia, C; Fernandes, J R A; Jorge, P A S

2014-12-15

An evanescent wave fiber optic sensor for detection of Escherichia coli (E. coli) outer membranes proteins (EcOMPs) using long period gratings (LPGs) as a refractometric platform is presented. The sensing probes were attained by the functionalization of LPGs inscribed in single mode fiber using two different methods of immobilization; electrostatic assembly and covalent binding. The resulting label-free configuration enabled the specific recognition of EcOMPs in water by monitoring the resonance wavelength shift due to refractive index changes induced by binding events. The sensors displayed linear responses in the range of 0.1 nM to 10 nM EcOMPs with sensitivities of -0.1563±0.005 nm decade(-1) [EcOMP, M] (electrostatic method) and -0.1597±0.004 nm decade(-1) [EcOMP, M] (covalent method). The devices could be regenerated (under low pH conditions) with a deviation less than 0.1% for at least three subsequent detection events. The sensors were also applied to spiked environmental water samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Distinct mechanisms for N-acetylcysteine inhibition of cytokine-induced E-selectin and VCAM-1 expression.

PubMed

Faruqi, R M; Poptic, E J; Faruqi, T R; De La Motte, C; DiCorleto, P E

1997-08-01

We have examined the effects of N-acetyl-L-cysteine (NAC), a well-characterized, thiol-containing antioxidant, on agonist-induced monocytic cell adhesion to endothelial cells (EC). NAC inhibited interleukin-1 (IL-1 beta)-induced, but not basal, adhesion with 50% inhibition at approximately 20 mM. Monocytic cell adhesion to EC in response to tumor necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS), alpha-thrombin, or phorbol 12-myristate 13-acetate (PMA) was similarly inhibited by NAC. Unlike published studies with pyrrolidinedithiocarbamate, which specifically inhibited vascular cell adhesion molecule 1 (VCAM-1), NAC inhibited IL-1 beta-induced mRNA and cell surface expression of both E-selectin and VCAM-1. NAC had no effect on the half-life of E-selectin or VCAM-1 mRNA. Although NAC reduced nuclear factor-kappa B (NF-kappa B) activation in EC as measured by gel-shift assays using an oligonucleotide probe corresponding to the consensus NF-kappa B binding sites of the VCAM-1 gene (VCAM-NF-kappa B), the antioxidant had no appreciable effect when an oligomer corresponding to the consensus NF-kappa B binding site of the E-selectin gene (E-selectin-NF-kappa B) was used. Because NF-kappa B has been reported to be redox sensitive, we studied the effects of NAC on the EC redox environment. NAC caused an expected dramatic increase in the reduced glutathione (GSH) levels in EC. In vitro studies demonstrated that whereas the binding affinity of NF-kappa B to the VCAM-NF-kappa B oligomer peaked at a GSH-to-oxidized glutathione (GSSG) ratio of approximately 200 and decreased at higher ratios, the binding to the E-selectin-NF-kappa B oligomer appeared relatively unaffected even at ratios > 400, i.e., those achieved in EC treated with 40 mM NAC. These results suggest that NF-kappa B binding to its consensus sequences in the VCAM-1 and E-selectin gene exhibits marked differences in redox sensitivity, allowing for differential gene expression regulated by the same transcription factor. Our data also demonstrate that NAC increases the GSH-to-GSSG ratio within the EC suggesting one possible mechanism through which this antioxidant inhibits agonist-induced monocyte adhesion to EC.

Application of a fluorometric microplate algal toxicity assay for riverine periphytic algal species.

PubMed

Nagai, Takashi; Taya, Kiyoshi; Annoh, Hirochica; Ishihara, Satoru

2013-08-01

Although riverine periphytic algae attached to riverbed gravel are dominant species in flowing rivers, there is limited toxicity data on them because of the difficulty in cell culture and assays. Moreover, it is well known that sensitivity to pesticides differ markedly among species, and therefore the toxicity data for multiple species need to be efficiently obtained. In this study, we investigated the use of fluorometric microplate toxicity assay for testing periphytic algal species. We selected five candidate test algal species Desmodesmus subspicatus, Achnanthidium minutissimum, Navicula pelliculosa, Nitzschia palea, and Pseudanabaena galeata. The selected species are dominant in the river, include a wide range of taxon, and represent actual species composition. Other additional species were also used to compare the sensitivity and suitability of the microplate assay. A 96-well microplate was used as a test chamber and algal growth was measured by in-vivo fluorescence. Assay conditions using microplate and fluorometric measurement were established, and sensitivities of 3,5-dichlorophenol as a reference substance were assayed. The 50 percent effect concentrations (EC50s) obtained by fluorometric microplate assay and those obtained by conventional Erlenmeyer flask assay conducted in this study were consistent. Moreover, the EC50 values of 3,5-dichlorophenol were within the reported confidence intervals in literature. These results supported the validity of our microplate assay. Species sensitivity distribution (SSD) analysis was conducted using the EC50s of five species. The SSD was found to be similar to the SSD obtained using additional tested species, suggesting that SSD using the five species largely represents algal sensitivity. Our results provide a useful and efficient method for high-tier probabilistic ecological risk assessment of pesticides. Copyright © 2013 Elsevier Inc. All rights reserved.

Development of an artificial neural network model for risk assessment of skin sensitization using human cell line activation test, direct peptide reactivity assay, KeratinoSens™ and in silico structure alert parameter.

PubMed

Hirota, Morihiko; Ashikaga, Takao; Kouzuki, Hirokazu

2018-04-01

It is important to predict the potential of cosmetic ingredients to cause skin sensitization, and in accordance with the European Union cosmetic directive for the replacement of animal tests, several in vitro tests based on the adverse outcome pathway have been developed for hazard identification, such as the direct peptide reactivity assay, KeratinoSens™ and the human cell line activation test. Here, we describe the development of an artificial neural network (ANN) prediction model for skin sensitization risk assessment based on the integrated testing strategy concept, using direct peptide reactivity assay, KeratinoSens™, human cell line activation test and an in silico or structure alert parameter. We first investigated the relationship between published murine local lymph node assay EC3 values, which represent skin sensitization potency, and in vitro test results using a panel of about 134 chemicals for which all the required data were available. Predictions based on ANN analysis using combinations of parameters from all three in vitro tests showed a good correlation with local lymph node assay EC3 values. However, when the ANN model was applied to a testing set of 28 chemicals that had not been included in the training set, predicted EC3s were overestimated for some chemicals. Incorporation of an additional in silico or structure alert descriptor (obtained with TIMES-M or Toxtree software) in the ANN model improved the results. Our findings suggest that the ANN model based on the integrated testing strategy concept could be useful for evaluating the skin sensitization potential. Copyright © 2017 John Wiley & Sons, Ltd.

Clinical Utility of Preoperative Computed Tomography in Patients With Endometrial Cancer.

PubMed

Bogani, Giorgio; Gostout, Bobbie S; Dowdy, Sean C; Multinu, Francesco; Casarin, Jvan; Cliby, William A; Frigerio, Luigi; Kim, Bohyun; Weaver, Amy L; Glaser, Gretchen E; Mariani, Andrea

2017-10-01

The aim of this study was to determine the clinical utility of routine preoperative pelvic and abdominal computed tomography (CT) examinations in patients with endometrial cancer (EC). We retrospectively reviewed records from patients with EC who underwent a preoperative endometrial biopsy and had surgery at our institution from January 1999 through December 2008. In the subset with an abdominal CT scan obtained within 3 months before surgery, we evaluated the clinical utility of the CT scan. Overall, 224 patients (18%) had a preoperative endometrial biopsy and an available CT scan. Gross intra-abdominal disease was observed in 10% and 20% of patients with preoperative diagnosis of endometrioid G3 and type II EC, respectively, whereas less than 5% of patients had a preoperative diagnosis of hyperplasia or low-grade EC. When examining retroperitoneal findings, we observed that a negative CT scan of the pelvis did not exclude the presence of pelvic node metastasis. Alternately, a negative CT scan in the para-aortic area generally reduced the probability of finding para-aortic dissemination but with an overall low sensitivity (42%). However, the sensitivity for para-aortic dissemination was as high as 67% in patients with G3 endometrioid cancer. In the case of negative para-aortic nodes in the CT scan, the risk of para-aortic node metastases decreased from 18.8% to 7.5% in patients with endometrioid G3 EC. Up to 15% of patients with endometrioid G3 cancer had clinically relevant incidental findings that necessitated medical or surgical intervention. In patients with endometrioid G3 and type II EC diagnosed by the preoperative biopsy, CT scans may help guide the operative plan by facilitating preoperative identification of gross intra-abdominal disease and enlarged positive para-aortic nodes that are not detectable during physical examinations. In addition, CT may reveal other clinically relevant incidental findings.

Role of MLH1 methylation in esophageal cancer carcinogenesis and its clinical significance.

PubMed

Li, Jinyun; Ye, Dong; Wang, Lei; Peng, Yingying; Li, Qun; Deng, Hongxia; Zhou, Chongchang

2018-01-01

The mutL homolog-1 ( MLH1 ) is a DNA mismatch repair gene and has been reported to be frequently methylated in numerous cancers. However, the association between MLH1 methylation and esophageal cancer (EC), as well as its clinical significance, remains unclear. Hence, we conducted a systematic meta-analysis based on 19 articles (including 1384 ECs, 345 premalignant lesions, and 1244 healthy controls). Our analysis revealed that the frequency of MLH1 methylation was significantly elevated during EC carcinogenesis. In addition, we observed that MLH1 promoter methylation was associated with age (odds ratio [OR]=1.79; 95% CI =1.20-2.66), advanced tumor grade (OR=3.7; 95% CI =2.37-5.77), lymph node metastasis (OR=2.65; 95% CI =1.81-3.88), distant metastasis (OR=7.60; 95% CI =1.23-47.19), advanced clinical stage (OR=4.46; 95% CI =2.88-6.91), and poor prognosis in EC patients (hazard ratio =1.64, 95% CI =1.00-2.69). The pooled sensitivity, specificity, and area under the curve of MLH1 methylation in EC patients versus healthy individuals were 0.15, 0.99, and 0.77, respectively. Our findings indicate that MLH1 methylation is involved in the carcinogenesis, progression, and metastasis of EC. Moreover, methylated MLH1 could be a potential diagnostic and prognostic biomarker for EC.

Role of MLH1 methylation in esophageal cancer carcinogenesis and its clinical significance

PubMed Central

Li, Jinyun; Ye, Dong; Wang, Lei; Peng, Yingying; Li, Qun; Deng, Hongxia

2018-01-01

The mutL homolog-1 (MLH1) is a DNA mismatch repair gene and has been reported to be frequently methylated in numerous cancers. However, the association between MLH1 methylation and esophageal cancer (EC), as well as its clinical significance, remains unclear. Hence, we conducted a systematic meta-analysis based on 19 articles (including 1384 ECs, 345 premalignant lesions, and 1244 healthy controls). Our analysis revealed that the frequency of MLH1 methylation was significantly elevated during EC carcinogenesis. In addition, we observed that MLH1 promoter methylation was associated with age (odds ratio [OR]=1.79; 95% CI =1.20–2.66), advanced tumor grade (OR=3.7; 95% CI =2.37–5.77), lymph node metastasis (OR=2.65; 95% CI =1.81–3.88), distant metastasis (OR=7.60; 95% CI =1.23–47.19), advanced clinical stage (OR=4.46; 95% CI =2.88–6.91), and poor prognosis in EC patients (hazard ratio =1.64, 95% CI =1.00–2.69). The pooled sensitivity, specificity, and area under the curve of MLH1 methylation in EC patients versus healthy individuals were 0.15, 0.99, and 0.77, respectively. Our findings indicate that MLH1 methylation is involved in the carcinogenesis, progression, and metastasis of EC. Moreover, methylated MLH1 could be a potential diagnostic and prognostic biomarker for EC. PMID:29440913

Specific cellular accumulation of photofrin-II in EC cells promotes photodynamic treatment efficacy in esophageal cancer.

PubMed

Gao, Shegan; Liang, Shuo; Ding, Kaili; Qu, Zhifeng; Wang, Ying; Feng, Xiaoshan

2016-06-01

Photodynamic therapy (PDT), which uses a light-sensitive compound and laser irradiation, is a light-based oncological treatment modality. PDT offers an alternative, less invasive treatment for various malignant tumors, such as esophageal cancer (EC), through a photochemical reaction induced by photofrin-II or other oncotropic photosensitizers without severe complications. Previous studies has shown that cancerous tissues accumulated more photosensitizers than paired normal tissues, however, whether it is cellular or vascular mechanisms remains unknown. Herein, in vivo and in vitro examinations were performed to study the mechanisms by which photofrin-II effectively and specifically killed EC cells. In this study, EC tissue of patients treated with photofrin-II, human ESCC cellline SHEEC and parental normal cellline SHEE, primary culture cells of EC tissue were used. The concentration of photofrin-II in cells were evaluated by high-performance liquid chromatography (HPLC). The results exhibited that accumulation of photofrin-II in cancerous cells were significantly higher than that in non-cancerous cells (p<0.05) under certain dose and time period of incubation of photofrin-II. In summary, our study showed that, photofrin-II specifically accumulated in EC cells in vivo and in vitro after controlling for vascular factors, which provided strong evidence that maybe the cellular factor is the main mechanism by which photofrin-II-mediated PDT selectively caused EC cells death. Copyright © 2016 Elsevier B.V. All rights reserved.

Spatial and Temporal Variations of EC and OC Aerosol Combustion Sources in a Polluted Metropolitan Area

NASA Astrophysics Data System (ADS)

Mouteva, G.; Randerson, J. T.; Fahrni, S.; Santos, G.; Bush, S. E.; Ehleringer, J. R.; Czimczik, C. I.

2015-12-01

Anthropogenic emissions of carbonaceous aerosols are a major component of fine air particulate matter (PM2.5) in polluted metropolitan areas and in the global atmosphere. Elemental (EC) and organic carbon (OC) aerosols influence Earth's energy balance by means of direct and indirect pathways and EC has been suggested as a better indicator of public health impacts from combustion-related sources than PM mass. Quantifying the contribution of fossil fuel and biomass combustion to the EC and OC emissions and their temporal and spatial variations is critical for developing efficient legislative air pollution control measures and successful climate mitigation strategies. In this study, we used radiocarbon (14C) to separate and quantify fossil and biomass contributions to a time series of EC and OC collected at 3 locations in Salt Lake City (SLC). Aerosol samples were collected on quartz fiber filters and a modified OC/EC analyzer was used with the Swiss_4S protocol to isolate and trap the EC fraction. Together with the total carbon (TC) content of the samples, the EC was analyzed for its 14C content with accelerator mass spectrometry. The 14C of OC was derived as a mass balance difference between TC and EC. EC had an annual average fraction modern of 0.13±0.06 and did not vary significantly across seasons. OC had an annual average FM of 0.49±0.13, with the winter mean (0.43±0.11) lower than the summer mean (0.64±0.13) at the 5% significance level. While the 3 stations were chosen to represent a variety of environmental conditions within SLC, no major differences in this source partitioning were observed between stations. During winter, the major sources of air pollutants in SLC are motor vehicles and wood stove combustion and determining their relative contributions has been the subject of debate. Our results indicated that fossil fuels were the dominant source of carbonaceous aerosols during winter, contributing 87% or more of the total EC mass and 40-75% of the OC. This suggests that fossil fuel-derived emissions should be a target for improving air quality during winter in SLC.

Sensitivity of ring growth and carbon allocation to climatic variation vary within ponderosa pine trees.

PubMed

Kerhoulas, Lucy P; Kane, Jeffrey M

2012-01-01

Most dendrochronological studies focus on cores sampled from standard positions (main stem, breast height), yet vertical gradients in hydraulic constraints and priorities for carbon allocation may contribute to different growth sensitivities with position. Using cores taken from five positions (coarse roots, breast height, base of live crown, mid-crown branch and treetop), we investigated how radial growth sensitivity to climate over the period of 1895-2008 varies by position within 36 large ponderosa pines (Pinus ponderosa Dougl.) in northern Arizona. The climate parameters investigated were Palmer Drought Severity Index, water year and monsoon precipitation, maximum annual temperature, minimum annual temperature and average annual temperature. For each study tree, we generated Pearson correlation coefficients between ring width indices from each position and six climate parameters. We also investigated whether the number of missing rings differed among positions and bole heights. We found that tree density did not significantly influence climatic sensitivity to any of the climate parameters investigated at any of the sample positions. Results from three types of analyses suggest that climatic sensitivity of tree growth varied with position height: (i) correlations of radial growth and climate variables consistently increased with height; (ii) model strength based on Akaike's information criterion increased with height, where treetop growth consistently had the highest sensitivity and coarse roots the lowest sensitivity to each climatic parameter; and (iii) the correlation between bole ring width indices decreased with distance between positions. We speculate that increased sensitivity to climate at higher positions is related to hydraulic limitation because higher positions experience greater xylem tensions due to gravitational effects that render these positions more sensitive to climatic stresses. The low sensitivity of root growth to all climatic variables measured suggests that tree carbon allocation to coarse roots is independent of annual climate variability. The greater number of missing rings in branches highlights the fact that canopy development is a low priority for carbon allocation during poor growing conditions.

Climate Sensitivity in the Anthropocene

NASA Technical Reports Server (NTRS)

Previdi, M.; Liepert, B. G.; Peteet, Dorothy M.; Hansen, J.; Beerling, D. J.; Broccoli, A. J.; Frolking, S.; Galloway, J. N.; Heimann, M.; LeQuere, C.;

Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions

PubMed Central

Zeebe, Richard E.

2013-01-01

Climate sensitivity measures the response of Earth’s surface temperature to changes in forcing. The response depends on various climate processes that feed back on the initial forcing on different timescales. Understanding climate sensitivity is fundamental to reconstructing Earth’s climatic history as well as predicting future climate change. On timescales shorter than centuries, only fast climate feedbacks including water vapor, lapse rate, clouds, and snow/sea ice albedo are usually considered. However, on timescales longer than millennia, the generally higher Earth system sensitivity becomes relevant, including changes in ice sheets, vegetation, ocean circulation, biogeochemical cycling, etc. Here, I introduce the time-dependent climate sensitivity, which unifies fast-feedback and Earth system sensitivity. I show that warming projections, which include a time-dependent climate sensitivity, exhibit an enhanced feedback between surface warming and ocean CO2 solubility, which in turn leads to higher atmospheric CO2 levels and further warming. Compared with earlier studies, my results predict a much longer lifetime of human-induced future warming (23,000–165,000 y), which increases the likelihood of large ice sheet melting and major sea level rise. The main point regarding the legacy of anthropogenic greenhouse gas emissions is that, even if the fast-feedback sensitivity is no more than 3 K per CO2 doubling, there will likely be additional long-term warming from slow climate feedbacks. Time-dependent climate sensitivity also helps explaining intense and prolonged warming in response to massive carbon release as documented for past events such as the Paleocene–Eocene Thermal Maximum. PMID:23918402

Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions.

PubMed

Zeebe, Richard E

2013-08-20

Climate sensitivity measures the response of Earth's surface temperature to changes in forcing. The response depends on various climate processes that feed back on the initial forcing on different timescales. Understanding climate sensitivity is fundamental to reconstructing Earth's climatic history as well as predicting future climate change. On timescales shorter than centuries, only fast climate feedbacks including water vapor, lapse rate, clouds, and snow/sea ice albedo are usually considered. However, on timescales longer than millennia, the generally higher Earth system sensitivity becomes relevant, including changes in ice sheets, vegetation, ocean circulation, biogeochemical cycling, etc. Here, I introduce the time-dependent climate sensitivity, which unifies fast-feedback and Earth system sensitivity. I show that warming projections, which include a time-dependent climate sensitivity, exhibit an enhanced feedback between surface warming and ocean CO2 solubility, which in turn leads to higher atmospheric CO2 levels and further warming. Compared with earlier studies, my results predict a much longer lifetime of human-induced future warming (23,000-165,000 y), which increases the likelihood of large ice sheet melting and major sea level rise. The main point regarding the legacy of anthropogenic greenhouse gas emissions is that, even if the fast-feedback sensitivity is no more than 3 K per CO2 doubling, there will likely be additional long-term warming from slow climate feedbacks. Time-dependent climate sensitivity also helps explaining intense and prolonged warming in response to massive carbon release as documented for past events such as the Paleocene-Eocene Thermal Maximum.

Climate sensitivity, sea level and atmospheric carbon dioxide

PubMed Central

Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

2013-01-01

Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1°C for a 4 W m−2 CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3–4°C for a 4 W m−2 CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change. PMID:24043864

Climate sensitivity, sea level and atmospheric carbon dioxide.

PubMed

Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

2013-10-28

Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1(°)C for a 4 W m(-2) CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3-4(°)C for a 4 W m(-2) CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.

State-dependent climate sensitivity in past warm climates and its implications for future climate projections.

PubMed

Caballero, Rodrigo; Huber, Matthew

2013-08-27

Projections of future climate depend critically on refined estimates of climate sensitivity. Recent progress in temperature proxies dramatically increases the magnitude of warming reconstructed from early Paleogene greenhouse climates and demands a close examination of the forcing and feedback mechanisms that maintained this warmth and the broad dynamic range that these paleoclimate records attest to. Here, we show that several complementary resolutions to these questions are possible in the context of model simulations using modern and early Paleogene configurations. We find that (i) changes in boundary conditions representative of slow "Earth system" feedbacks play an important role in maintaining elevated early Paleogene temperatures, (ii) radiative forcing by carbon dioxide deviates significantly from pure logarithmic behavior at concentrations relevant for simulation of the early Paleogene, and (iii) fast or "Charney" climate sensitivity in this model increases sharply as the climate warms. Thus, increased forcing and increased slow and fast sensitivity can all play a substantial role in maintaining early Paleogene warmth. This poses an equifinality problem: The same climate can be maintained by a different mix of these ingredients; however, at present, the mix cannot be constrained directly from climate proxy data. The implications of strongly state-dependent fast sensitivity reach far beyond the early Paleogene. The study of past warm climates may not narrow uncertainty in future climate projections in coming centuries because fast climate sensitivity may itself be state-dependent, but proxies and models are both consistent with significant increases in fast sensitivity with increasing temperature.

Trends in fire risk and burned area in Brazil in the 20th century

NASA Astrophysics Data System (ADS)

Silva, P.; Bastos, A.; DaCamara, C.; Libonati, R.

2016-12-01

Fire has a significant contribution to the global greenhouse gas emissions and vast ecological and climatic impacts. Worldwide, Brazil is one of the areas most affected by fire, which highly influences the state of the vegetation cover, the ecological diversity of the region and has significant consequences to the global CO2 balance [1]. Hence, with the increasing evidence of human induced climate change, it becomes essential to understand the present and future trends of fire risk in Brazil. Although a large number of fires in Brazil are anthropogenic, it has been shown that the burned area is mainly controlled by meteorological conditions [2], therefore being partially determined by fire risk. In this study we use a fire danger index specifically tailored for the Brazilian climate and biome characteristics, the MFDI developed by INPE, to assess the patterns and trends of fire risk in Brazil. The index relies on values of maximum temperature, accumulated precipitation over different periods, minimum relative humidity and vegetation cover to estimate the likelihood of fire occurrence. We test the sensitivity of the index to different climate reanalyses and evaluate the trends in fire risk in Brazil during the past four decades for different biomes. We further assess the link between the calculated fire risk and observed fire occurrence and burned area. Finally, we compare the results with fire risk simulated by a regional climate model (RCA4 forced by EC-Earth from CORDEX) in order to evaluate its suitability for future projections of fire risk and burned area. [1] Bowman, D. M. et al. Fire in the earth system. Science, v. 324, p. 481-484, 24 apr. 2009. [2] Libonati, R. et al. An Algorithm for Burned Area Detection in the Brazilian Cerrado Using 4 μm MODIS Imagery. Remote Sensing, v. 7, p. 15782-15803, 2015.

Using "EC-Assess" to Assess a Small Biofuels Project in Honduras

ERIC Educational Resources Information Center

Ngassa, Franklin Chamda

2010-01-01

Biofuels may contribute to both rural economic development and climate change mitigation and adaptation. The Gota Verde Project in Yoro, Honduras, attempts to demonstrate the technical and economic feasibility of small-scale biofuel production for local use by implementing a distinctive approach to feedstock production that encourages small farm…

Detection of Celiac Disease and Lymphocytic Enteropathy by Parallel Serology and Histopathology in a Population-Based Study

PubMed Central

Walker, Marjorie M.; Murray, Joseph A.; Ronkainen, Jukka; Aro, Pertti; Storskrubb, Tom; D’Amato, Mauro; Lahr, Brian; Talley, Nicholas J.; Agreus, Lars

2010-01-01

Background & Aims Although serological analysis is used in diagnosis of celiac disease, histopathology is considered most reliable. We performed a prospective study to determine the clinical, pathological and serological spectrum of celiac disease in a general population (Kalixanda study). Methods A random sample of an adult general population (n=1000) was analyzed by upper endoscopy, duodenal biopsy, and serological analysis of tissue transglutaminase (tTg) levels; endomysial antibody (EMA) levels were analyzed in samples that were tTg+. The cutoff values for diagnosis of celiac disease were villous atrophy with 40 intraepithelial lymphocytes (IELs)/100 enterocytes (ECs). Results Samples from 33 subjects were tTg+ and 16 were EMA+. Histological analysis identified 7/1000 subjects (0.7%) with celiac disease; all were tTg+ and 6/7 were EMA+. Another 26 subjects were tTg+ (7/26 EMA+). This was addressed by a second quantitative pathology study, (nested case-control design) using a threshold of 25 IELS/100 ECs. In this analysis, all 13 samples that were tTg+ and EMA+ had ≥25 IELs/100ECs. In total, 16 subjects (1.6%) had serological and histological evidence of gluten-sensitive enteropathy. IELs were quantified in duodenal biopsy samples from seronegative individuals (n=500); 19 (3.8%) had >25 IELs and lymphocytic duodenosis (LD). Conclusions Measurement of ≥25 IELs/100 ECs correlated with serological indicators of celiac disease; a higher IEL threshold could miss 50% of cases. Quantification of tTg is a sensitive test for celiac disease; diagnosis can be confirmed by observation of ≥25 IELs/100ECs in duodenal biopsies. Lymphocytic enteropathy (celiac disease and LD) is common in the population (5.4%). PMID:20398668

Allosteric modulation of semicarbazide-sensitive amine oxidase activities in vitro by imidazoline receptor ligands

PubMed Central

Holt, Andrew; Wieland, Barbara; Baker, Glen B

2004-01-01

Evidence indicates that imidazoline I2 binding sites (I2BSs) are present on monoamine oxidase (MAO) and on soluble (plasma) semicarbazide-sensitive amine oxidase enzymes. The binding site on MAO has been described as a modulatory site, although no effects on activity are thought to have been observed as a result of ligands binding to these sites. We examined the effects in vitro of several imidazoline binding site ligands on activities of bovine plasma amine oxidase (BPAO) and porcine kidney diamine oxidase (PKDAO) in a spectrophotometric protocol. While both enzymes were inhibited at high concentrations of all ligands, clonidine, cirazoline and oxymetazoline were seen, at lower concentrations, to increase activity of BPAO versus benzylamine, but not of PKDAO versus putrescine. This effect was substrate dependent, with mixed or biphasic inhibition of spermidine, methylamine, p-tyramine and β-phenylethylamine oxidation observed at cirazoline concentrations that increased benzylamine oxidation. With benzylamine as substrate, clonidine decreased KM (EC50 8.82 μM, Emax 75.1% of control) and increased Vmax (EC50 164.6 μM, Emax 154.1% of control). Cirazoline decreased Vmax (EC50 2.15 μM, Emax 91.4% of control), then decreased KM (EC50 5.63 μM, Emax 42.6% of control) and increased Vmax (EC50 49.0 μM, Emax 114.4% of decreased Vmax value). Data for clonidine fitted a mathematical model for two-site nonessential activation plus linear intersecting noncompetitive inhibition. Data for cirazoline were consistent with involvement of a fourth site. These results reveal an ability of imidazoline ligands to modulate BPAO kinetics allosterically. The derived mechanism may have functional significance with respect to modulation of MAO by I2BS ligands. PMID:15451775

Satellite retrieval of actual evapotranspiration in the Tibetan Plateau: Components partitioning, multidecadal trends and dominated factors identifying

NASA Astrophysics Data System (ADS)

Wang, Weiguang; Li, Jinxing; Yu, Zhongbo; Ding, Yimin; Xing, Wanqiu; Lu, Wenjun

2018-04-01

As the only connecting term between water balance and energy budget in the earth-atmospheric system, evapotranspiration (ET) is considered the most excellent indicator for the activity for the water and energy cycle. Under the background of global change, regional ET estimates, components partitioning as well as their spatial and temporal patterns recognition are of great importance in understanding the hydrological processes and improving water management practices. This is particularly true for the Tibetan Plateau (TP), one of most sensitive and vulnerable region in response to the environment change in the earth. In this study, with flux site observation data and monthly ET data from the monthly water balance method incorporating the terrestrial water storage changes from the Gravity Recovery and Climate Experiment satellite (GRACE) production as the multiple validations, the long-term daily ET in the TP was retrieved by a modified Penman-Monteith-Leuning (PML) model with considering evapotranspiration over snow covered area during 1982-2012. The spatial and temporal changes of partitioned three components of ET, i.e., soil evaporation (Es), transpiration through the stomata of plant (Ec) and canopy interception (Ei), were investigated in the TP. Meanwhile, how the ET components contribute to ET changes and respond to the change in environmental factors in the TP was revealed and discussed. The results indicate that Es dominates ET in most areas of the TP with the mean annual ratio of 65.7%, except southeastern regions where the vegetation coverage is high. Although regional average ET and three main components all present obvious increase trends during the past decades, high spatial heterogeneity for their trends are identified in the TP. Moreover, a mixed changing pattern can be apparently found for Es in southeastern area, Ec and Ei in northwestern and southeastern area. Spatially, the ET variation are mainly attributed to change in Es, followed by Ec and Ei. In addition, compared with evaporation-related meteorological variables, precipitation and leaf area index (LAI) provide the more dominated contributions to the changes of ET and Ei in the TP, while LAI is overwhelming contribution factor for Ec changes. As for Es changes, although precipitation play the important role, the effects of other factors are also non-negligible.

Climate change impact assessment on Veneto and Friuli Plain groundwater. Part I: an integrated modeling approach for hazard scenario construction.

PubMed

Baruffi, F; Cisotto, A; Cimolino, A; Ferri, M; Monego, M; Norbiato, D; Cappelletto, M; Bisaglia, M; Pretner, A; Galli, A; Scarinci, A; Marsala, V; Panelli, C; Gualdi, S; Bucchignani, E; Torresan, S; Pasini, S; Critto, A; Marcomini, A

2012-12-01

Climate change impacts on water resources, particularly groundwater, is a highly debated topic worldwide, triggering international attention and interest from both researchers and policy makers due to its relevant link with European water policy directives (e.g. 2000/60/EC and 2007/118/EC) and related environmental objectives. The understanding of long-term impacts of climate variability and change is therefore a key challenge in order to address effective protection measures and to implement sustainable management of water resources. This paper presents the modeling approach adopted within the Life+ project TRUST (Tool for Regional-scale assessment of groUndwater Storage improvement in adaptation to climaTe change) in order to provide climate change hazard scenarios for the shallow groundwater of high Veneto and Friuli Plain, Northern Italy. Given the aim to evaluate potential impacts on water quantity and quality (e.g. groundwater level variation, decrease of water availability for irrigation, variations of nitrate infiltration processes), the modeling approach integrated an ensemble of climate, hydrologic and hydrogeologic models running from the global to the regional scale. Global and regional climate models and downscaling techniques were used to make climate simulations for the reference period 1961-1990 and the projection period 2010-2100. The simulation of the recent climate was performed using observed radiative forcings, whereas the projections have been done prescribing the radiative forcings according to the IPCC A1B emission scenario. The climate simulations and the downscaling, then, provided the precipitation, temperatures and evapo-transpiration fields used for the impact analysis. Based on downscaled climate projections, 3 reference scenarios for the period 2071-2100 (i.e. the driest, the wettest and the mild year) were selected and used to run a regional geomorphoclimatic and hydrogeological model. The final output of the model ensemble produced information about the potential variations of the water balance components (e.g. river discharge, groundwater level and volume) due to climate change. Such projections were used to develop potential hazard scenarios for the case study area, to be further applied within climate change risk assessment studies for groundwater resources and associated ecosystems. This paper describes the models' chain and the methodological approach adopted in the TRUST project and analyzes the hazard scenarios produced in order to investigate climate change risks for the case study area. Copyright © 2012 Elsevier B.V. All rights reserved.

Multi-wavelength optical measurement to enhance thermal/optical analysis for carbonaceous aerosol

NASA Astrophysics Data System (ADS)

Chen, L.-W. A.; Chow, J. C.; Wang, X. L.; Robles, J. A.; Sumlin, B. J.; Lowenthal, D. H.; Zimmermann, R.; Watson, J. G.

2015-01-01

A thermal/optical carbon analyzer equipped with seven-wavelength light source/detector (405-980 nm) for monitoring spectral reflectance (R) and transmittance (T) of filter samples allowed "thermal spectral analysis (TSA)" and wavelength (λ)-dependent organic-carbon (OC)-elemental-carbon (EC) measurements. Optical sensing was calibrated with transfer standards traceable to absolute R and T measurements, adjusted for loading effects to report spectral light absorption (as absorption optical depth (τa, λ)), and verified using diesel exhaust samples. Tests on ambient and source samples show OC and EC concentrations equivalent to those from conventional carbon analysis when based on the same wavelength (~ 635 nm) for pyrolysis adjustment. TSA provides additional information that evaluates black-carbon (BC) and brown-carbon (BrC) contributions and their optical properties in the near infrared to the near ultraviolet parts of the solar spectrum. The enhanced carbon analyzer can add value to current aerosol monitoring programs and provide insight into more accurate OC and EC measurements for climate, visibility, or health studies.

Multi-wavelength optical measurement to enhance thermal/optical analysis for carbonaceous aerosol

NASA Astrophysics Data System (ADS)

Chen, L.-W. A.; Chow, J. C.; Wang, X. L.; Robles, J. A.; Sumlin, B.; Lowenthal, D. H.; Zimmermann, R.; Watson, J. G.

2014-09-01

A thermal/optical carbon analyzer equipped with seven-wavelength light source/detector (405-980 nm) for monitoring spectral reflectance (R) and transmittance (T) of filter samples allows "thermal spectral analysis (TSA)" and wavelength (λ)-dependent organic carbon (OC)-elemental carbon (EC) measurements. Optical sensing is calibrated with transfer standards traceable to absolute R and T measurements and adjusted for loading effects to determine spectral light absorption (as absorption optical depth [τa, λ]) using diesel exhaust samples as a reference. Tests on ambient and source samples show OC and EC concentrations equivalent to those from conventional carbon analysis when based on the same wavelength (~635 nm) for pyrolysis adjustment. TSA provides additional information that evaluates black carbon (BC) and brown carbon (BrC) contributions and their optical properties in the near-IR to the near-UV parts of the solar spectrum. The enhanced carbon analyzer can add value to current aerosol monitoring programs and provide insight into more accurate OC and EC measurements for climate, visibility, or health studies.

Thermal/optical methods for elemental carbon quantification in soils and urban dusts: equivalence of different analysis protocols.

PubMed

Han, Yongming; Chen, Antony; Cao, Junji; Fung, Kochy; Ho, Fai; Yan, Beizhan; Zhan, Changlin; Liu, Suixin; Wei, Chong; An, Zhisheng

2013-01-01

Quantifying elemental carbon (EC) content in geological samples is challenging due to interferences of crustal, salt, and organic material. Thermal/optical analysis, combined with acid pretreatment, represents a feasible approach. However, the consistency of various thermal/optical analysis protocols for this type of samples has never been examined. In this study, urban street dust and soil samples from Baoji, China were pretreated with acids and analyzed with four thermal/optical protocols to investigate how analytical conditions and optical correction affect EC measurement. The EC values measured with reflectance correction (ECR) were found always higher and less sensitive to temperature program than the EC values measured with transmittance correction (ECT). A high-temperature method with extended heating times (STN120) showed the highest ECT/ECR ratio (0.86) while a low-temperature protocol (IMPROVE-550), with heating time adjusted for sample loading, showed the lowest (0.53). STN ECT was higher than IMPROVE ECT, in contrast to results from aerosol samples. A higher peak inert-mode temperature and extended heating times can elevate ECT/ECR ratios for pretreated geological samples by promoting pyrolyzed organic carbon (PyOC) removal over EC under trace levels of oxygen. Considering that PyOC within filter increases ECR while decreases ECT from the actual EC levels, simultaneous ECR and ECT measurements would constrain the range of EC loading and provide information on method performance. Further testing with standard reference materials of common environmental matrices supports the findings. Char and soot fractions of EC can be further separated using the IMPROVE protocol. The char/soot ratio was lower in street dusts (2.2 on average) than in soils (5.2 on average), most likely reflecting motor vehicle emissions. The soot concentrations agreed with EC from CTO-375, a pure thermal method.

The effect of tributyltin-oxide on earthworms, springtails, and plants in artificial and natural soils.

PubMed

Römbke, J; Jänsch, S; Junker, T; Pohl, B; Scheffczyk, A; Schallnass, H-J

2007-05-01

Chemical bioavailability in Organisation for Economic Co-operation and Development (OECD) artificial soil can contrast with bioavailability in natural soils and produce ecotoxicologic benchmarks that are not representative of species' exposure conditions in the field. Initially, reproduction and growth of earthworm and Collembolan species, and early seedling growth of a dicotyledonous plant species, in nine natural soils (with a wide range of physicochemical properties) and in OECD soil were evaluated. Soils that supported reproduction and growth of the test species were then used to investigate the toxicity of tributyltin-oxide (TBT-O). Natural soils caused greater toxicity of TBT-O to earthworms (EC(50) values varied from 0.5 to 4.7 mg/kg soil dry weight [dw]) compared with toxicity in OECD soil (EC(50) = 13.4 mg/kg dw). Collembolans were less sensitive to TBT-O than earthworms in natural soils, with EC(50) values ranging from 23.4 to 177.8 mg/kg dw. In contrast, the toxicity of TBT-O to collembolans in OECD soil (EC(50) = 104.0 mg/kg dw) was within the range of EC(50) values in natural soils. Phytotoxicity tests revealed even greater difference between the effects in natural soils (EC(50) values ranged from 10.7 to 189.2 mg/kg dw) and in OECD soil (EC(50) = 535.5 mg/kg dw) compared with results of the earthworm tests. Studies also showed that EC(50) values were a more robust end point compared with EC(10) values based on comparisons of coefficients of variation. These results show that toxicity testing should include studies with natural soils in addition to OECD soil to better reflect exposure conditions in the field.

Environmental drivers of spatial variation in whole-tree transpiration in an aspen-dominated upland-to-wetland forest gradient

NASA Astrophysics Data System (ADS)

Loranty, Michael M.; Mackay, D. Scott; Ewers, Brent E.; Adelman, Jonathan D.; Kruger, Eric L.

2008-02-01

Assumed representative center-of-stand measurements are typical inputs to models that scale forest transpiration to stand and regional extents. These inputs do not consider gradients in transpiration at stand boundaries or along moisture gradients and therefore potentially bias the large-scale estimates. We measured half-hourly sap flux (JS) for 173 trees in a spatially explicit cyclic sampling design across a topographically controlled gradient between a forested wetland and upland forest in northern Wisconsin. Our analyses focused on three dominant species in the site: quaking aspen (Populus tremuloides Michx), speckled alder (Alnus incana (DuRoi) Spreng), and white cedar (Thuja occidentalis L.). Sapwood area (AS) was used to scale JS to whole tree transpiration (EC). Because spatial patterns imply underlying processes, geostatistical analyses were employed to quantify patterns of spatial autocorrelation across the site. A simple Jarvis type model parameterized using a Monte Carlo sampling approach was used to simulate EC (EC-SIM). EC-SIM was compared with observed EC(EC-OBS) and found to reproduce both the temporal trends and spatial variance of canopy transpiration. EC-SIM was then used to examine spatial autocorrelation as a function of environmental drivers. We found no spatial autocorrelation in JS across the gradient from forested wetland to forested upland. EC was spatially autocorrelated and this was attributed to spatial variation in AS which suggests species spatial patterns are important for understanding spatial estimates of transpiration. However, the range of autocorrelation in EC-SIM decreased linearly with increasing vapor pressure deficit, implying that consideration of spatial variation in the sensitivity of canopy stomatal conductance to D is also key to accurately scaling up transpiration in space.

Drivers of variability in tree transpiration in a Boreal Black Spruce Forest Chronosequence

NASA Astrophysics Data System (ADS)

Angstmann, J. L.; Ewers, B. E.; Kwon, H.

2009-12-01

Boreal forests are of particular interest in climate change studies because of their large land area and ability to sequester and store carbon, which is controlled by water availability. Heterogeneity of these forests is predicted to increase with climate change through the impact of more frequent wildfires, warmer, longer growing seasons, and potential drainage of forested wetlands. This study aims to quantify the influence of stand age, drainage condition, and species on tree transpiration and its drivers in a central Canadian black spruce boreal forest. Heat dissipation sensors were installed in 113 trees (69 Picea mariana (black spruce), 25 Populus tremuloides (trembling aspen), and 19 Pinus banksiana (jack pine) at four stand ages, each containing a well- and poorly-drained site over three growing seasons (2006-2008). Sap flux per unit xylem area, JS, was expressed as transpiration per unit ground area, EC, and transpiration per unit leaf area, EL, using site- and species-specific allometry to obtain sapwood area (AS)and leaf area(AL)per unit ground area. Well-drained, younger Picea mariana daily JS was 47-64% greater than the older well-drained burn ages and younger poorly-drained stands were 64-68% greater than the two oldest poorly-drained stands. Daily EL in the well-drained Picea mariana stands was on average 12-33% higher in younger stand than in the two oldest stands whereas young, poorly-drained Picea mariana had 71% greater daily EL than the older stands. Well-drained Picea mariana trees had 52% higher daily EC than older trees and poorly-drained Picea mariana in the 1964 burn had 42-81% higher daily EC than the oldest stands. Populus tremuloides located in the two youngest stands had daily JS 38-58% greater rates than the 1930 burn, whereas daily EL and EC had no distint differences due to high interannual variability. Pinus banksiana experienced 21-33% greater daily JS in the 1989 burn than in the older 1964 burn for well- and poorly-drained sites. Poorly-drained Pinus banksiana trees from the older 1964 burn had 23-48% greater daily EL and 26-39% higher daily EC than the 1989 burn. Poorly-drained Picea mariana had 17-31% higher daily JS than the well-drained sites. Poorly-drained Picea mariana had 29-58% higher daily EL 42-50% higher daily EC than the well-drained trees. Poorly-drained Pinus banksiana on average had 27-28% higher daily JS than well-drained trees. Poorly-drained Pinus banskiana had 23.25% higher daily EL than well-drained trees and daily EC 32-67% lower than the well-drained trees. Drivers of these differences include midday leaf water potential, AS, and AL.

The longitudinal interplay of affective and cognitive empathy within and between adolescents and mothers.

PubMed

van Lissa, Caspar J; Hawk, Skyler T; de Wied, Minet; Koot, Hans M; van Lier, Pol; Meeus, Wim

2014-04-01

This 4-year study examined longitudinal interplays between adolescents' and mothers' self-reported empathic concern (EC) and perspective taking (PT). We investigated (a) whether adolescents' EC predicted rank-order change in their PT over time, or vice versa; (b) whether mothers' empathy predicted relative increases in adolescents' empathy; (c) whether adolescent gender moderated the over-time links from mothers' to adolescents' empathy; and (d) whether the rank-order stability of EC and PT over time differed within and between respondents. Adolescents' EC positively predicted their PT over time, but not vice versa. Mothers' PT positively predicted adolescent PT over time for girls, but not for boys. The rank-order stability of adolescents' EC was greater than their PT. Maternal PT and EC were equally stable and were more stable than in adolescents. This study contributes the first empirical evidence that the developmental order of adolescents' empathy runs from affective to cognitive empathy, in contrast to prior theoretical and experimental literature that has emphasized the reverse direction. It further provides the 1st longitudinal evidence of intergenerational empathy transmission. These findings support the notion that adolescence is a developmentally sensitive period for PT. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Development of a sequential workflow based on LC-PRM for the verification of endometrial cancer protein biomarkers in uterine aspirate samples.

PubMed

Martinez-Garcia, Elena; Lesur, Antoine; Devis, Laura; Campos, Alexandre; Cabrera, Silvia; van Oostrum, Jan; Matias-Guiu, Xavier; Gil-Moreno, Antonio; Reventos, Jaume; Colas, Eva; Domon, Bruno

2016-08-16

About 30% of endometrial cancer (EC) patients are diagnosed at an advanced stage of the disease, which is associated with a drastic decrease in the 5-year survival rate. The identification of biomarkers in uterine aspirate samples, which are collected by a minimally invasive procedure, would improve early diagnosis of EC. We present a sequential workflow to select from a list of potential EC biomarkers, those which are the most promising to enter a validation study. After the elimination of confounding contributions by residual blood proteins, 52 potential biomarkers were analyzed in uterine aspirates from 20 EC patients and 18 non-EC controls by a high-resolution accurate mass spectrometer operated in parallel reaction monitoring mode. The differential abundance of 26 biomarkers was observed, and among them ten proteins showed a high sensitivity and specificity (AUC > 0.9). The study demonstrates that uterine aspirates are valuable samples for EC protein biomarkers screening. It also illustrates the importance of a biomarker verification phase to fill the gap between discovery and validation studies and highlights the benefits of high resolution mass spectrometry for this purpose. The proteins verified in this study have an increased likelihood to become a clinical assay after a subsequent validation phase.

Effects of the pyrethroid insecticide gamma-cyhalothrin on aquatic invertebrates in laboratory and outdoor microcosm tests.

PubMed

van Wijngaarden, René P A; Barber, Ian; Brock, Theo C M

2009-02-01

The sensitivity of a range of freshwater lentic invertebrates to gamma-cyhalothrin (GCH), a single enantiomer of the synthetic pyrethroid lambda-cyhalothrin, was assessed in single species laboratory tests and an outdoor multi-species ecosystem test. The most sensitive species in the laboratory single species tests with GCH was Chaoborus obscuripes (96 h EC(50): 3.8 ng/l). The species sensitivity distribution curve, based on the laboratory 96 h EC(50) acute toxicity data for eight species, gave a median HC(5) value for GCH of 2.12 ng/l. The NOEC(community) derived from the multi-species ecosystem test was 5 ng/l, and the insects Chaoborus sp. and Caenis sp. were identified as the most sensitive species. The results indicate that the median HC(5), based on eight species selected to include those known to be sensitive to pyrethroids, provided a good estimation of the NOEC(community) for GCH. Furthermore, the results for GCH indicated that the endpoints typically used in higher-tier risk assessments for pesticides in Europe (HC(5) and NOEC(community)) were consistent with expectations when compared to the equivalent endpoints for the racemate LCH.

Sensitivity of Scenedesmus obliquus and Microcystis aeruginosa to atrazine: effects of acclimation and mixed cultures, and their removal ability.

PubMed

Chalifour, Annie; LeBlanc, André; Sleno, Lekha; Juneau, Philippe

2016-12-01

Atrazine is an herbicide frequently detected in watercourses that can affect the phytoplankton community, thus impacting the whole food chain. This study aims, firstly, to measure the sensitivity of monocultures of the green alga Scenedemus obliquus and toxic and non-toxic strains of the cyanobacteria Microcystis aeruginosa before, during and after a 30-day acclimation period to 0.1 µM of atrazine. Secondly, the sensitivity of S. obliquus and M. aeruginosa to atrazine in mixed cultures was evaluated. Finally, the ability of these strains to remove atrazine from the media was measured. We demonstrated that both strains of M. aeruginosa had higher growth rate-based EC 50 values than S. obliquus when exposed to atrazine, even though their photosynthesis-based EC 50 values were lower. After being exposed to 0.1 µM of atrazine for 1 month, only the photosynthesis-based EC 50 of S. obliquus increased significantly. In mixed cultures, the growth rate of the non-toxic strain of M. aeruginosa was higher than S. obliquus at high concentrations of atrazine, resulting in a ratio of M. aeruginosa to total cell count of 0.6. This lower sensitivity might be related to the higher growth rate of cyanobacteria at low light intensity. Finally, a negligible fraction of atrazine was removed from the culture media by S. obliquus or M. aeruginosa over 6 days. These results bring new insights on the acclimation of some phytoplankton species to atrazine and its effect on the competition between S. obliquus and M. aeruginosa in mixed cultures.

Differential antioxidative responses to dehydration-induced oxidative stress in core set of foxtail millet cultivars [Setaria italica (L.)].

PubMed

Lata, Charu; Jha, Sarita; Dixit, Vivek; Sreenivasulu, Nese; Prasad, Manoj

2011-10-01

Foxtail millet (Setaria italica L.) known as a relatively drought-tolerant crop across the world is grown in arid and semi-arid regions. To the best of our knowledge, no systematic study on drought tolerance screening of foxtail millet germplasm being a drought-tolerant crop has been reported so far. To explore genetic diversity of drought-induced oxidative stress tolerance in foxtail millet, we employed lipid peroxidation measure to assess membrane integrity under stress as biochemical marker to screen 107 cultivars and classified the genotypes as highly tolerant, tolerant, sensitive, and highly sensitive. From this comprehensive screening, four cultivars showing differential response to dehydration tolerance were selected to understand the physiological and biochemical basis of tolerance mechanisms. The dehydration-tolerant cultivars (IC-403579 and Prasad) showed considerably lower levels of lipid peroxidation and electrolyte leakage as compared with dehydration-sensitive cultivars (IC-480117 and Lepakshi), indicating better cell membrane integrity in tolerant cultivars. Correspondingly, tolerant genotypes maintained higher activity of catalase (EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11), and glutathione reductase (GR; EC 1.6.4.2) across different time-course period of polyethylene glycol (PEG) treatments in comparison to sensitive ones. The above biochemical results were further validated through quantitative real-time PCR analysis of APX and GR, whose transcripts were substantially induced by PEG treatments in tolerant cultivars. These results suggest that tolerant cultivars possess wider array of antioxidant machinery with efficient ascorbate-glutathione pathway to cope with drought-induced oxidative stress.

Effects of in-situ and reanalysis climate data on estimation of cropland gross primary production using the Vegetation Photosynthesis Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Cui; Xiao, Xiangming; Wagle, Pradeep

2015-11-01

Satellite-based Production Efficiency Models (PEMs) often require meteorological reanalysis data such as the North America Regional Reanalysis (NARR) by the National Centers for Environmental Prediction (NCEP) as model inputs to simulate Gross Primary Production (GPP) at regional and global scales. This study first evaluated the accuracies of air temperature (TNARR) and downward shortwave radiation (RNARR) of the NARR by comparing with in-situ meteorological measurements at 37 AmeriFlux non-crop eddy flux sites, then used one PEM – the Vegetation Photosynthesis Model (VPM) to simulate 8-day mean GPP (GPPVPM) at seven AmeriFlux crop sites, and investigated the uncertainties in GPPVPM from climatemore » inputs as compared with eddy covariance-based GPP (GPPEC). Results showed that TNARR agreed well with in-situ measurements; RNARR, however, was positively biased. An empirical linear correction was applied to RNARR, and significantly reduced the relative error of RNARR by ~25% for crop site-years. Overall, GPPVPM calculated from the in-situ (GPPVPM(EC)), original (GPPVPM(NARR)) and adjusted NARR (GPPVPM(adjNARR)) climate data tracked the seasonality of GPPEC well, albeit with different degrees of biases. GPPVPM(EC) showed a good match with GPPEC for maize (Zea mays L.), but was slightly underestimated for soybean (Glycine max L.). Replacing the in-situ climate data with the NARR resulted in a significant overestimation of GPPVPM(NARR) (18.4/29.6% for irrigated/rainfed maize and 12.7/12.5% for irrigated/rainfed soybean). GPPVPM(adjNARR) showed a good agreement with GPPVPM(EC) for both crops due to the reduction in the bias of RNARR. The results imply that the bias of RNARR introduced significant uncertainties into the PEM-based GPP estimates, suggesting that more accurate surface radiation datasets are needed to estimate primary production of terrestrial ecosystems at regional and global scales.« less

The effect of time of day on cold water ingestion by high-level swimmers in a tropical climate.

PubMed

Hue, Olivier; Monjo, Roland; Lazzaro, Marc; Baillot, Michelle; Hellard, Philippe; Marlin, Laurent; Jean-Etienne, A

2013-07-01

The authors tested the effect of cold water ingestion during high-intensity training in the morning vs the evening on both core temperature (TC) and thermal perceptions of internationally ranked long-distance swimmers during a training period in a tropical climate. Nine internationally ranked long-distance swimmers (5 men and 4 women) performed 4 randomized training sessions (2 in the evening and 2 in the morning) with 2 randomized beverages with different temperatures for 3 consecutive days. After a standardized warm-up of 1000 m, the subjects performed a standardized training session that consisted of 10 x 100 m (start every 1'20″) at a fixed velocity. The swimmers were then followed for the next 3000 m of the training schedule. Heart rate (HR) was continuously monitored during the 10 x 100 m, whereas TC, thermal comfort, and thermal sensation (TS) were measured before and after each 1000-m session. Before and after each 1000 m, the swimmers were asked to drink 190 mL of neutral (26.5 ± 2.5°C) or cold (1.3 ± 0.3°C) water packaged in standardized bottles. Results demonstrated that cold water ingestion induced a significant effect on TC, with a pronounced decrease in the evening, resulting in significantly lower mean TC and lower mean delta TC in evening cold (EC) than in evening neutral (EN), concomitant with significantly lower TS in EC than in EN and a significant effect on exercise HR. Moreover, although TC increased significantly with time in MN, MC, and EN, TC was stabilized during exercise in EC. To conclude, we demonstrate that a cold beverage had a significant effect on TC, TS, and HR during training in high-level swimmers in a tropical climate, especially during evening training.

Response of dissolved inorganic carbon (DIC) and δ13CDIC to changes in climate and land cover in SW China karst catchments

NASA Astrophysics Data System (ADS)

Zhao, Min; Liu, Zaihua; Li, Hong-Chun; Zeng, Cheng; Yang, Rui; Chen, Bo; Yan, Hao

2015-09-01

Monthly hydrochemical data and δ13C of dissolved inorganic carbon (DIC) in karst water samples from September 2007 to October 2012 were obtained to reveal the controlling mechanisms on DIC geochemistry and δ13CDIC under different conditions of climate and land cover in three karst catchments: Banzhai, Dengzhanhe and Chenqi, in Guizhou Province, SW China. DIC of karst water at the Banzhai site comes mainly from carbonate dissolution under open system conditions with soil CO2 produced by root respiration and organic carbon decomposition with lowest δ13C values under its dense virgin forest coverage. Weaker carbonate bedrock dissolution due to sparse and thin soil cover results in lower δ13CDIC, pCO2, DIC and EC, and lower cation and anion concentrations. At the Chenqi site, larger soil CO2 input from a thick layer of soil results in high pCO2 and DIC, and low pH, SIc and δ13CDIC in the karst water. At the Dengzhanhe site, a lesser soil CO2 input due to stronger karst rock desertification and strong gypsum dissolution contribute to higher δ13CDIC, high EC and high cation and anion concentrations. Soil CO2 inputs, controlled by biological activity and available soil moisture, carbonate bedrock dissolution, dilution and degassing effects, vary seasonally following rainfall and temperature changes. Consequently, there are seasonal cycles in hydrochemistry and δ13CDIC of the karst water, with high pCO2 and low pH, EC, SIc, and δ13CDIC values in the warm and rainy seasons, and vice versa during the cold and dry seasons. A strongly positive shift (>3‰) in δ13CDIC occurred in the drought year, 2011, indicating that δ13CDIC in groundwater systems can be an effective indicator of environmental and/or climate changes.

Size-mediated tree transpiration along soil drainage gradients in a boreal black spruce forest wildfire chronosequence.

PubMed

Angstmann, J L; Ewers, B E; Kwon, H

2012-05-01

Boreal forests are crucial to climate change predictions because of their large land area and ability to sequester and store carbon, which is controlled by water availability. Heterogeneity of these forests is predicted to increase with climate change through more frequent wildfires, warmer, longer growing seasons and potential drainage of forested wetlands. This study aims at quantifying controls over tree transpiration with drainage condition, stand age and species in a central Canadian black spruce boreal forest. Heat dissipation sensors were installed in 2007 and data were collected through 2008 on 118 trees (69 Picea mariana (Mill.) Britton, Sterns & Poggenb. (black spruce), 25 Populus tremuloides Michx. (trembling aspen), 19 Pinus banksiana Lamb. (jack pine), 3 Larix laricina (Du Roi) K. Koch (tamarack) and 2 Salix spp. (willow)) at four stand ages (18, 43, 77 and 157 years old) each containing a well- and poorly-drained stand. Transpiration estimates from sap flux were expressed per unit xylem area, J(S), per unit ground area, E(C) and per unit leaf area, E(L), using sapwood (A(S)) and leaf (A(L)) area calculated from stand- and species-specific allometry. Soil drainage differences in transpiration were variable; only the 43- and 157-year-old poorly-drained stands had ∼ 50% higher total stand E(C) than well-drained locations. Total stand E(C) tended to decrease with stand age after an initial increase between the 18- and 43-year-old stands. Soil drainage differences in transpiration were controlled primarily by short-term physiological drivers such as vapor pressure deficit and soil moisture whereas stand age differences were controlled by successional species shifts and changes in tree size (i.e., A(S)). Future predictions of boreal climate change must include stand age, species and soil drainage heterogeneity to avoid biased estimates of forest water loss and latent energy exchanges.

Pliocene Paleoenvironments of the Awash Valley, Ethiopia: The Isotope Record of Tooth Enamel and its Relevance to the Pliocene Paleoclimate of Northeastern Africa

NASA Astrophysics Data System (ADS)

Bedaso, Z. K.; Wynn, J. G.; Alemseged, Z.

2010-12-01

Understanding patterns of Pliocene environmental and climate change using data from terrestrial deposits helps to identify factors which govern the climate, and to unravel potential links between regional and global climate conditions. We use the stable carbon (C) and oxygen (O) isotopic composition of bioapatite from fossil tooth enamel to reconstruct Pliocene environmental and climatic changes at Dikika and Galili, in the Awash valley of Ethiopia. Our application of C and O isotopes aims principally at reconstructing shifts in floral composition, such as the relative abundance of C4 grasses, and its implications for climate indicators including temperature, aridity, and seasonality, and the role of climate in early hominin evolution. C isotopic composition of tooth enamel is based on differences in C isotope discrimination between plants that use the two major photosynthetic pathways (C3 and C4), the abundance of which are driven by climate variables, and the transfer of this “signature” between plant foods in the diet of mammals and mammalian tooth enamel δ13C values (ɛdiet-enamel). A change in δ13Cenamel values between 5.26 and 3.24 Ma provides insight to early hominin environments, which varied from open woodland and grassland to closed woodland in the early to mid Pliocene at Galili and wooded grassland both in Galili and Dikika in the late Pliocene. Similarly, the O isotopic composition of tooth enamel is a function of the isotopic composition of body water, which in turn is a function of meteoric and physiological processes, and therefore may also reflect local climatic conditions if the physiological factors can be constrained. Using an O isotope enrichment factor between δ18Oenamel carbonate and δ18Obody water (ɛEC-BW =26.3) and between evaporation sensitive and insensitive taxa (ɛES-EI = 2.1-4.2), we estimate the Pliocene δ18O value of meteoric water, which ranges from -2.4 to -5.2 ‰ in early and mid Pliocene respectively. An observed change in an estimate of water deficit during the Pliocene of this region may in part be attributed to a regional change in moisture source or to mid Pliocene regional climate change.

OM/OC Ratio and Specific Attenuation Coefficient in Ambient Particulate Matter at a Rural Site in Southern Ontario: Implications for Aerosol Aging and Emission Sources

NASA Astrophysics Data System (ADS)

Chan, T. W.; Huang, L.; Leaitch, R.; Sharma, S.; Brook, J.; Slowik, J.; Abbatt, J.

2008-05-01

Carbonaceous species (organic carbon (OC) and elemental carbon (EC)) contribute a large portion of atmospheric fine particle mass and influence air quality, human health, and climate forcing. However, their emission sources and atmospheric aging processes are not well understood. The OM/OC ratio, defined as the organic mass per unit OC mass, is useful to understand the degree of oxidation of aerosol particles in atmospheric processes. We define the modified BC/EC (mod BC/EC) ratio as the ratio of the non-scattering corrected absorption coefficient per unit mass of EC. The mod BC/EC ratio has a similar meaning as the site specific attenuation coefficient, which is an important parameter used to convert light absorption measurements to black carbon mass. The mod BC/EC ratio can vary due to light scattering effect on absorption measurements, in which the oxygenated organics may play a role. The pyrolysis organic carbon (POC) is defined as the carbon mass fraction obtained at T= 870°C under a pure helium environment using the thermal separation method [Huang et al., 2006]. Since POC mass is generally proportional to the amount of oxygenated OC, studying the relationships among OC, EC, POC, as well as OM/OC and mod BC/EC ratios may help us understand the mechanisms of aerosol aging from different emission sources. Two 1-month field studies were conducted at a rural site in southern Ontario (NW of Toronto) during fall 2005 and spring 2007. Quartz filter samples were collected and analyzed for OC, POC, and EC concentrations using a thermal/optical method [Huang et al., 2006]. Together with the total organic matter measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and the absorption coefficient obtained from a Particle Soot Absorption Photometer (PSAP), the OM/OC and mod BC/EC ratios for ambient aerosols were obtained. Our results show that when air mass was mainly from south, OC, POC, and EC were relatively high, with average ratios of OC/EC, OM/OC, and POC/EC as 1.94, 1.41, and 0.52, respectively; this indicates significant anthropogenic impacts and relatively large portion of oxygenated OC, which might be due to either primary emissions or photo-chemical reactions occurred in a short period of time. When air mass was mainly from north, OC, POC, and EC were much lower, with average ratios of OC/EC, OM/OC, and POC/EC as 3.10, 1.20, and 0.79, respectively; this suggests less influence from anthropogenic emissions and relatively aged air mass from biogenic-source dominated clean air. Using POC, we estimate the specific attenuation at the site to be 5.8 m2 g-1 independent of the air mass origin. The relationships among OM/OC, mod BC/EC, and POC will be further discussed. References: Huang, L., Brook, J.R., Zhang, W., Li, S.M., Graham, L., Ernst, D., Chivulescu, A., and Lu, G. (2006) Stable isotope measurements of carbon fractions (OC/EC) in airborne particulate: a new dimension for source characterization and apportionment, Atmospheric Environment, 40, 2690-2705.

State-dependent climate sensitivity in past warm climates and its implications for future climate projections

PubMed Central

Caballero, Rodrigo; Huber, Matthew

2013-01-01

Projections of future climate depend critically on refined estimates of climate sensitivity. Recent progress in temperature proxies dramatically increases the magnitude of warming reconstructed from early Paleogene greenhouse climates and demands a close examination of the forcing and feedback mechanisms that maintained this warmth and the broad dynamic range that these paleoclimate records attest to. Here, we show that several complementary resolutions to these questions are possible in the context of model simulations using modern and early Paleogene configurations. We find that (i) changes in boundary conditions representative of slow “Earth system” feedbacks play an important role in maintaining elevated early Paleogene temperatures, (ii) radiative forcing by carbon dioxide deviates significantly from pure logarithmic behavior at concentrations relevant for simulation of the early Paleogene, and (iii) fast or “Charney” climate sensitivity in this model increases sharply as the climate warms. Thus, increased forcing and increased slow and fast sensitivity can all play a substantial role in maintaining early Paleogene warmth. This poses an equifinality problem: The same climate can be maintained by a different mix of these ingredients; however, at present, the mix cannot be constrained directly from climate proxy data. The implications of strongly state-dependent fast sensitivity reach far beyond the early Paleogene. The study of past warm climates may not narrow uncertainty in future climate projections in coming centuries because fast climate sensitivity may itself be state-dependent, but proxies and models are both consistent with significant increases in fast sensitivity with increasing temperature. PMID:23918397

Radiosensitization of Human Vascular Endothelial Cells Through Hsp90 Inhibition With 17-N-Allilamino-17-Demethoxygeldanamycin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kabakov, Alexander E.; Makarova, Yulia M.; Malyutina, Yana V.

Purpose: In addition to invasive tumor cells, endothelial cells (ECs) of the tumor vasculature are an important target for anticancer radiotherapy. The purpose of the present work is to investigate how 17-N-allilamino-17-demethoxygeldanamycin (17AAG), known as an anticancer drug inhibiting heat shock protein 90 (Hsp90), modifies radiation responses of human vascular ECs. Methods and Materials: The ECs cultured from human umbilical veins were exposed to {gamma}-irradiation, whereas some EC samples were pretreated with growth factors and/or 17AAG. Postirradiation cell death/survival and morphogenesis were assessed by means of terminal deoxynucleotidyl transferase biotin-deoxyuridine triphosphate nick end labeling or annexin V staining and clonogenicmore » and tube-formation assays. The 17AAG-affected expression and phosphorylation of radioresistance-related proteins were probed by means of immunoblotting. Dominant negative or constitutively activated Akt was transiently expressed in ECs to manipulate Akt activity. Results: It was found that nanomolar concentrations of 17AAG sensitize ECs to relatively low doses (2-6 Gy) of {gamma}-irradiation and abolish the radioprotective effects of vascular endothelial growth factor and basic fibroblast growth factor. The drug-induced radiosensitization of ECs seems to be caused by prevention of Hsp90-dependent phosphorylation (activation) of Akt that results in blocking the radioprotective phosphatidylinositol 3-kinase/Akt pathway. Conclusions: Clinically achievable concentrations of 17AAG can decrease the radioresistance intrinsic to vascular ECs and minimize the radioprotection conferred upon them by tumor-derived growth factors. These findings characterize 17AAG as a promising radiosensitizer for the tumor vasculature.« less

The relationship between CD86/CD54 expression and THP-1 cell viability in an in vitro skin sensitization test--human cell line activation test (h-CLAT).

PubMed

Sakaguchi, Hitoshi; Ashikaga, Takao; Miyazawa, Masaaki; Kosaka, Nanae; Ito, Yuichi; Yoneyama, Katsurako; Sono, Sakiko; Itagaki, Hiroshi; Toyoda, Hidekazu; Suzuki, Hiroyuki

2009-04-01

Recent regulations for cosmetics in Europe prohibit animal testing for evaluating the sensitization potential of chemicals to improve animal welfare. Yet, there is not an acceptable Organization for Economic Co-operation and Development non-animal skin sensitization test method. Several in vitro skin sensitization methods that focus on the activation of Langerhans cells, including human cell lines, are being evaluated as possible alternatives. In our previous study, we optimized our human cell line activation test (h-CLAT) using THP-1 cells (monocytic leukemia cell line) and conducted an inter-laboratory study. We found that measuring CD86/CD54 expression may be useful for predicting skin sensitization. The aim of this study was to confirm the relationship between CD86/CD54 expression and THP-1 cell viability in the h-CLAT. In this study, 21 allergens (e.g., dinitrochlorobenzene, p-phenylenediamine, Ni) and 8 non-allergens (e.g., SLS, lactic acid) were evaluated. For each chemical, more than 10 concentrations that gave a predicted cell viability range of 20-95% were used. The data showed that expression patterns of CD86/CD54 differed depending on chemical. For most allergens, cytotoxicity (65-90% cell viability) was needed for enhancement of CD86/CD54 expression. The criteria of "CD86 > or = 150 or CD54 > or = 200" resulted in an accuracy of 93%, which confirms appropriate cut-off criteria for h-CLAT. Furthermore, a good correlation was observed between EC3 of local lymph node assay and EC150(CD86) or EC200(CD54) of h-CLAT (12 or 16 chemicals, respectively), which would provide a useful estimate of allergic potency. These findings suggest that h-CLAT would be a good robust in vitro skin sensitization test.

Improving together: better science writing through peer learning

NASA Astrophysics Data System (ADS)

Stiller-Reeve, Mathew A.; Heuzé, Céline; Ball, William T.; White, Rachel H.; Messori, Gabriele; van der Wiel, Karin; Medhaug, Iselin; Eckes, Annemarie H.; O'Callaghan, Amee; Newland, Mike J.; Williams, Sian R.; Kasoar, Matthew; Wittmeier, Hella Elisa; Kumer, Valerie

2016-07-01

Science, in our case the climate and geosciences, is increasingly interdisciplinary. Scientists must therefore communicate across disciplinary boundaries. For this communication to be successful, scientists must write clearly and concisely, yet the historically poor standard of scientific writing does not seem to be improving. Scientific writing must improve, and the key to long-term improvement lies with the early-career scientist (ECS). Many interventions exist for an ECS to improve their writing, like style guides and courses. However, momentum is often difficult to maintain after these interventions are completed. Continuity is key to improving writing. This paper introduces the ClimateSnack project, which aims to motivate ECSs to develop and continue to improve their writing and communication skills. The project adopts a peer-learning framework where ECSs voluntarily form writing groups at different institutes around the world. The group members learn, discuss, and improve their writing skills together. Several ClimateSnack writing groups have formed. This paper examines why some of the groups have flourished and others have dissolved. We identify the challenges involved in making a writing group successful and effective, notably the leadership of self-organized groups, and both individual and institutional time management. Within some of the groups, peer learning clearly offers a powerful tool to improve writing as well as bringing other benefits, including improved general communication skills and increased confidence.

Chronic toxicity of copper to five benthic invertebrates in laboratory-formulated sediment: sensitivity comparison and preliminary risk assessment.

PubMed

Roman, Yblin E; De Schamphelaere, Karel A C; Nguyen, Lien T H; Janssen, Colin R

2007-11-15

Five benthic organisms commonly used for sediment toxicity testing were chronically (28 to 35 days) exposed to copper in standard laboratory-formulated sediment (following Organization for Economic Cooperation and Development guidelines) and lethal and sub-lethal toxicities were evaluated. Sub-lethal endpoints considered were reproduction and biomass production for Lumbriculus variegatus, growth and reproduction for Tubifex tubifex, growth and emergence for Chironomus riparius, and growth for Gammarus pulex and Hyalella azteca. Expressed on whole-sediment basis the observed lethal sensitivity ranking (from most to least sensitive) was: G. pulex>L. variegatus>H. azteca=C. riparius=T. tubifex, with median chronic lethal concentrations (LC50) between 151 and 327 mg/kg dry wt. The sub-lethal sensitivity ranking (from most to least sensitive, with the most sensitive endpoint between parentheses): C. riparius (emergence)>T. tubifex (reproduction)=L. variegatus (reproduction)>G. pulex (growth)>H. azteca (growth), with median effective concentrations (EC50) between 59.2 and 194 mg/kg dry wt. No observed effect concentrations (NOEC) or 10% effective concentrations (EC10) for the five benthic invertebrates were used to perform a preliminary risk assessment for copper in freshwater sediment by means of (a) the "assessment factor approach" or (b) the statistical extrapolation approach (species sensitivity distribution). Depending on the data (NOEC or EC10) and the methodology used, we calculated a Predicted No Effect Concentration (PNEC) for sediment between 3.3 and 47.1 mg Cu/dry wt. This range is similar to the range of natural (geochemical) background concentrations of copper in sediments in Europe, i.e. 90% of sediments have a concentration between 5 and 49 mg Cu/kg dry wt. A detailed analysis of the outcome of this preliminary exercise highlighted that multiple issues need to be explored for achieving a scientifically more sound risk assessment and for the development of robust sediment quality criteria for copper, including (i) the use of the assessment factor approach vs. the statistical extrapolation approach, (ii) the importance of bioavailability modifying factors (e.g., organic carbon, acid volatile sulfide), and (iii) the influence of prevailing geochemical (bioavailable) background concentrations on the copper sensitivity of local benthic biota.

Relationship between Hard X-Ray Footpoint Sources and Photospheric Electric Currents in Solar Flares: a Statistical Study

NASA Astrophysics Data System (ADS)

Zimovets, I. V.; Sharykin, I. N.; Wang, R.; Liu, Y. D.; Kosovichev, A. G.

2017-12-01

It is believed that solar flares are a result of release of free magnetic energy contained in electric currents (ECs) flowing in active regions (ARs). However, there are still debates whether the primary energy release and acceleration of electrons take place in coronal current sheets or in chromospheric footpoints of current-carrying magnetic flux tubes (loops). We present results of an observational statistical study of spatial relationship between hard X-ray (HXR; EHXR≥50keV) footpoint sources detected by RHESSI and vertical photospheric ECs calculated using vector magnetograms obtained from the SDO/HMI data. We found that for a sample of 47 flares (from C3.0 to X3.1 class) observed on the solar disk by both instruments in 2010-2016, at least one HXR source was in a region of strong (within 20% of the maximum EC density in the corresponding ARs) vertical ECs having the form of a ribbon (79%) or an island (21%). The total vertical ECs in such HXR sources are in the range of 1010-1013 A. The EC density is in the range of 0.01-1.0 A/m2. We found no correlation between intensity of the HXR sources and the EC density. By comparing pre-flare and post-flare EC maps we did not find evidences of significant dissipation of vertical ECs in the regions corresponding to the HXR sources. In some cases, we found amplification of ECs during flares. We discuss effects of sensitivity and angular resolution of RHESSI and SDO/HMI. In general, the results indicate that there is a link between the flare HXR footpoint sources and enhanced vertical ECs in the photosphere. However, the results do not support a concept of electron acceleration by the electric field excited in footpoints of current-carrying loops due to some (e.g. Rayleigh-Taylor) instabilities (Zaitsev et al., 2016), since strong correlation between the HXR intensity and the EC density is expected in such concept.

Elemental and Organic Carbon Measurements at the Kosetice Observatory, Czech Republic within EU Projects in 2009-2014

NASA Astrophysics Data System (ADS)

Vana, M.; Holubova, A.; Cech, J.

2016-12-01

Carbonaceous aerosol (TC) is a complex mixture of many organics (OC fraction) and elemental carbon (EC). EC is a product of anthropogenic activities, especially incomplete combustion of fossil fuels by transport, heating, power plants, wood and biomass burning and agriculture activities. EC could have larger health impact than other PM constituents (Cassee et al., 2013). Carbonaceous aerosols also play an important role in climate change (Boucher et al., 2013). Kosetice Observatory, operated by the Czech Hydrometeorological Institute has been carrying out long-term air quality monitoring at the background scale the Czech Republic since 1988. Regular EC-OC measurement has been implementing within EU-projects EUSAAR and ACTRIS since 2009. Sampling frequency is every 6th day in fraction PM2,5 on 2 quartz-fibre filters. Since October 2011 the sampling on filters has been implementing behind the denuder catching the organic vapor. Amount of OC on back quartz fiber filter represents positive artifact by measurement without denuder and negative artifact by measurements with denuder. The analytical method is thermal-optical analysis. The samples are analyzed in CHMI Central Laboratories in Prague-Libuš using EC-OC Sunset Lab Dual Analyzer. Charring correction is made by laser transmission monitoring. Slightly decreasing tendency of EC-OC was found in the period under review (2009-2014). The mean annual concentration of total carbon (TC) in PM2,5 was 3,73 µg.m-3. The figure for elemental carbon (0,5 µg.m-3) represents the mean annual ratio of 13% on TC. EC-OC concentrations follow an annual course that reflects their emission levels, i.e. with maximums in winter and minimums in summer. The seasonal variation of EC/TC ratio ranges between 9,6 (summer) - 14,2% (winter). Mean TC ratio on PM2,5 total mass in the period under review was 29%, the highest ratios reached 50%. EC participated on PM2,5 total mass by 3,5% in average. 3D trajectories were used for sector analysis of measured EC-OC data (NILU, 2016). The highest concentrations are recorded in situations when air masses reach the territory of the Czech Republic from the north-eastern directions or the local air masses prevailing. The differences between sectors are much larger in the cold period of the year.

Chinese insurance agents in "bad barrels": a multilevel analysis of the relationship between ethical leadership, ethical climate and business ethical sensitivity.

PubMed

Zhang, Na; Zhang, Jian

2016-01-01

The moral hazards and poor public image of the insurance industry, arising from insurance agents' unethical behavior, affect both the normal operation of an insurance company and decrease applicants' confidence in the company. Contrarily, these scandals may demonstrate that the organizations were "bad barrels" in which insurance agents' unethical decisions were supported or encouraged by the organization's leadership or climate. The present study brings two organization-level factors (ethical leadership and ethical climate) together and explores the role of ethical climate on the relationship between the ethical leadership and business ethical sensitivity of Chinese insurance agents. Through the multilevel analysis of 502 insurance agents from 56 organizations, it is found that organizational ethical leadership is positively related to the organizational ethical climate; organizational ethical climate is positively related to business ethical sensitivity, and organizational ethical climate fully mediates the relationship between organizational ethical leadership and business ethical sensitivity. Organizational ethical climate plays a completely mediating role in the relationship between organizational ethical leadership and business ethical sensitivity. The integrated model of ethical leadership, ethical climate and business ethical sensitivity makes several contributions to ethics theory, research and management.

Time variation of effective climate sensitivity in GCMs

NASA Astrophysics Data System (ADS)

Williams, K. D.; Ingram, W. J.; Gregory, J. M.

2009-04-01

Effective climate sensitivity is often assumed to be constant (if uncertain), but some previous studies of General Circulation Model (GCM) simulations have found it varying as the simulation progresses. This complicates the fitting of simple models to such simulations, as well as having implications for the estimation of climate sensitivity from observations. This study examines the evolution of the feedbacks determining the climate sensitivity in GCMs submitted to the Coupled Model Intercomparison Project. Apparent centennial-timescale variations of effective climate sensitivity during stabilisation to a forcing can be considered an artefact of using conventional forcings which only allow for instantaneous effects and stratospheric adjustment. If the forcing is adjusted for processes occurring on timescales which are short compared to the climate stabilisation timescale then there is little centennial timescale evolution of effective climate sensitivity in any of the GCMs. We suggest that much of the apparent variation in effective climate sensitivity identified in previous studies is actually due to the comparatively fast forcing adjustment. Persistent differences are found in the strength of the feedbacks between the coupled atmosphere - ocean (AO) versions and their atmosphere - mixed-layer ocean (AML) counterparts, (the latter are often assumed to give the equilibrium climate sensitivity of the AOGCM). The AML model can typically only estimate the equilibrium climate sensitivity of the parallel AO version to within about 0.5K. The adjustment to the forcing to account for comparatively fast processes varies in magnitude and sign between GCMs, as well as differing between AO and AML versions of the same model. There is evidence from one AOGCM that the forcing adjustment may take a couple of decades, with implications for observationally based estimates of equilibrium climate sensitivity. We suggest that at least some of the spread in 21st century global temperature predictions between GCMs is due to differing adjustment processes, hence work to understand these differences should be a priority.

Ecotoxicology of bromoacetic acid on estuarine phytoplankton.

PubMed

Gordon, Ana R; Richardson, Tammi L; Pinckney, James L

2015-11-01

Bromoacetic acid is formed when effluent containing chlorine residuals react with humics in natural waters containing bromide. The objective of this research was to quantify the effects of bromoacetic acid on estuarine phytoplankton as a proxy for ecosystem productivity. Bioassays were used to measure the EC50 for growth in cultured species and natural marine communities. Growth inhibition was estimated by changes in chlorophyll a concentrations measured by fluorometry and HPLC. The EC50s for cultured Thalassiosira pseudonana were 194 mg L(-1), 240 mg L(-1) for Dunaliella tertiolecta and 209 mg L(-1) for Rhodomonas salina. Natural phytoplankton communities were more sensitive to contamination with an EC50 of 80 mg L(-1). Discriminant analysis suggested that bromoacetic acid additions cause an alteration of phytoplankton community structure with implications for higher trophic levels. A two-fold EC50 decrease in mixed natural phytoplankton populations affirms the importance of field confirmation for establishing water quality criteria. Copyright © 2015 Elsevier Ltd. All rights reserved.

Taxonomy, Traits, and Environment Determine Isoprenoid Emission from an Evergreen Tropical forest.

NASA Astrophysics Data System (ADS)

Taylor, T.; Alves, E. G.; Tota, J.; Oliveira Junior, R. C.; Camargo, P. B. D.; Saleska, S. R.

2016-12-01

Volatile isoprenoid emissions from the leaves of tropical forest trees significantly affects atmospheric chemistry, aerosols, and cloud dynamics, as well as the physiology of the emitting leaves. Emission is associated with plant tolerance to heat and drought stress. Despite a potentially central role of isoprenoid emissions in tropical forest-climate interactions, we have a poor understanding of the relationship between emissions and ecological axes of forest function. We used a custom instrument to quantify leaf isoprenoid emission rates from over 200 leaves and 80 trees at a site in the eastern Brazilian Amazon. We related standardized leaf emission capacity (EC: leaf emission rate at 1000 PAR) to tree taxonomy, height, light environment, wood traits, and leaf traits. Taxonomy was the strongest predictor of EC, and non-emitters could be found throughout the canopy. But we found that environment and leaf carbon economics constrained the upper bound of EC. For example, the relationship between EC and specific leaf area (SLA; fresh leaf area / dry mass) is described by an envelope with a decreasing upper bound on EC as SLA increases (quantile regression: 85th quantile, p<0.01). That result suggests a limitation on emissions related to leaf carbon investment strategies. EC was highest in the mid-canopy, and in leaves growing under less direct light. While inferences of ecosystem emissions focus on environmental conditions in the canopy, our results suggest that sub-canopy leaves are more responsive. This work is allowing us to develop an ecological understanding of isoprenoid emissions from forests, the basis for a predictive model of emissions that depends on both environmental factors and biological emission capacity that is grounded in plant traits and phylogeny.

Deriving a light use efficiency model from eddy covariance flux data for predicting daily gross primary production across biomes

USGS Publications Warehouse

Yuan, W.; Liu, S.; Zhou, G.; Tieszen, L.L.; Baldocchi, D.; Bernhofer, C.; Gholz, H.; Goldstein, Allen H.; Goulden, M.L.; Hollinger, D.Y.; Hu, Y.; Law, B.E.; Stoy, Paul C.; Vesala, T.; Wofsy, S.C.

2007-01-01

The quantitative simulation of gross primary production (GPP) at various spatial and temporal scales has been a major challenge in quantifying the global carbon cycle. We developed a light use efficiency (LUE) daily GPP model from eddy covariance (EC) measurements. The model, called EC-LUE, is driven by only four variables: normalized difference vegetation index (NDVI), photosynthetically active radiation (PAR), air temperature, and the Bowen ratio of sensible to latent heat flux (used to calculate moisture stress). The EC-LUE model relies on two assumptions: First, that the fraction of absorbed PAR (fPAR) is a linear function of NDVI; Second, that the realized light use efficiency, calculated from a biome-independent invariant potential LUE, is controlled by air temperature or soil moisture, whichever is most limiting. The EC-LUE model was calibrated and validated using 24,349 daily GPP estimates derived from 28 eddy covariance flux towers from the AmeriFlux and EuroFlux networks, covering a variety of forests, grasslands and savannas. The model explained 85% and 77% of the observed variations of daily GPP for all the calibration and validation sites, respectively. A comparison with GPP calculated from the Moderate Resolution Imaging Spectroradiometer (MODIS) indicated that the EC-LUE model predicted GPP that better matched tower data across these sites. The realized LUE was predominantly controlled by moisture conditions throughout the growing season, and controlled by temperature only at the beginning and end of the growing season. The EC-LUE model is an alternative approach that makes it possible to map daily GPP over large areas because (1) the potential LUE is invariant across various land cover types and (2) all driving forces of the model can be derived from remote sensing data or existing climate observation networks.

Quaternary seismic stratigraphy and paleoenvironments on the continental shelf of the East China Sea

NASA Astrophysics Data System (ADS)

Liu, Zhen-Xia; Berne, Serge; Saito, Yoshiki; Lericolais, G.; Marsset, T.

2000-08-01

Paleoenvironments and stratigraphy have been interpreted from 4380 km of seismic profiling collected during a geological and geophysical cruise on the continental shelf of the East China Sea (ECS) undertaken in 1996. The geophysical data are correlated with a borehole situated on the outer shelf obtained by Shanghai Marine Geology Bureau, indicating that six seismic units have been preserved since oxygen-isotope stage 6, including four regressive-transgressive cycles. Seismic units U2, U3+U4+U5, U6, and U7 are interpreted to correspond respectively to oxygen-isotope stages 1, 3, 5, and 6, implying that sediment partitioning and sequence architecture in the ECS have been controlled by glacio-eustasy and global climate changes. Alternating continental and marine strata corresponding to glaciation and interglaciation are well preserved on the outer shelf of the ECS. Most of the cold environment strata, which formed on the outer shelf during oxygen-isotope stages 2 and 4, are too thin to be recognized on SIG 600J because of resolution, but corresponding erosion surfaces exist. Seismic unit U7 is widespread over the shelf, extending to the continental edge and showing little variation in thickness, as the regression was pronounced and lasted a long time. Thus, U7 can be used as a marker layer for correlation of Quaternary strata on the shelf of the ECS. Post-glacial transgression is obvious in the ECS. Marine strata with varied thickness were developed in the shallow sea of the inner shelf, thinning toward the outer shelf. The continental shelf of the ECS has been influenced by Pacific tide-wave systems for a long time, forming tidal sand-ridge sequences, developed during transgressions, corresponding to oxygen-isotope stages 7 (or 9), 5, 3 and 1.

Determination of Ethyl Carbamate in Chinese Yellow Rice Wine by Diatomaceous Earth Extraction and GC/MS Method.

PubMed

Wu, Pinggu; Zhang, Liqun; Shen, Xianghong; Wang, Liyuan; Zou, Yan; Zhang, Jing; Tan, Ying; Tang, Jun; Ma, Bingjie; Pan, Xiaodong; Jiang, Wei

2015-01-01

A sensitive and rapid analytical method based on alkaline diatomaceous earth extraction followed by GC/MS was developed for the quantitative determination of the toxic contaminant ethyl carbamate (EC) in yellow rice wines. The optimal extraction conditions were investigated. With the application of diatomaceous earth extraction, the damage of organic acids to the capillary column was greatly reduced. By using d5-EC as an internal standard for quantitative analysis of EC, the linearity of the calibration curves was good between 10 and 1000 ng/mL. The LOD and LOQ were 1.7 and 5.0 μg/kg, respectively. The spiked level of EC was 5.0-300 μg/kg, and the average recovery of the spikes was between 78.4 and 98.2%, with an RSD between 4.3 and 8.3%. Upon validation by five laboratories when spiked with 50, 100, and 300 μg/kg, the average respective recoveries were 102.9, 102.2, and 98.7% with a RSD between 0.7 and 8.1%. The validation results demonstrated that the method is fast, simple, selective, and suitable for the determination of EC in yellow rice wines.

Congenital myopathy results from misregulation of a muscle Ca2+ channel by mutant Stac3

PubMed Central

Linsley, Jeremy W.; Hsu, I-Uen; Groom, Linda; Yarotskyy, Viktor; Lavorato, Manuela; Horstick, Eric J.; Linsley, Drew; Wang, Wenjia; Franzini-Armstrong, Clara; Dirksen, Robert T.; Kuwada, John Y.

2017-01-01

Skeletal muscle contractions are initiated by an increase in Ca2+ released during excitation–contraction (EC) coupling, and defects in EC coupling are associated with human myopathies. EC coupling requires communication between voltage-sensing dihydropyridine receptors (DHPRs) in transverse tubule membrane and Ca2+ release channel ryanodine receptor 1 (RyR1) in the sarcoplasmic reticulum (SR). Stac3 protein (SH3 and cysteine-rich domain 3) is an essential component of the EC coupling apparatus and a mutation in human STAC3 causes the debilitating Native American myopathy (NAM), but the nature of how Stac3 acts on the DHPR and/or RyR1 is unknown. Using electron microscopy, electrophysiology, and dynamic imaging of zebrafish muscle fibers, we find significantly reduced DHPR levels, functionality, and stability in stac3 mutants. Furthermore, stac3NAM myofibers exhibited increased caffeine-induced Ca2+ release across a wide range of concentrations in the absence of altered caffeine sensitivity as well as increased Ca2+ in internal stores, which is consistent with increased SR luminal Ca2+. These findings define critical roles for Stac3 in EC coupling and human disease. PMID:28003463

MiR-218 inhibits HMGB1-mediated autophagy in endometrial carcinoma cells during chemotherapy.

PubMed

Ran, Xiaomin; Yang, Juan; Liu, Chaoxia; Zhou, Ping; Xiao, Linzhi; Zhang, Keqiang

2015-01-01

Endometrial carcinoma is the most common gynecological malignancy among women worldwide. Although treatment for EC has improved with the introduction of Paclitaxel (Tax) chemotherapy, the majority of patients will develop resistance to the treatment, leading to poor prognosis. One of the causes of chemoresistance is the increased ability to undergo autophagy. In this study, we identified that miR-218 was significantly down-regulated in Tax-resistant EC cells compared to the non-drug resistant cell lines, and overexpression of miR-218 sensitized paclitaxel resistant EC cells to paclitaxel. Moreover, we demonstrated that miR-218 directly binds to the 3'-UTR of HMGB1 gene. HMGB1 was upregulated in paclitaxel resistant EC cells, it mediated autophagy and contributed to chemotherapy resistance in endometrial carcinoma in vitro. HMGB1-mediated autophagy could be suppressed by miR-218 overexpression in Tax resistant EC cells. In summary, we determined the targeting role of miR-218 to HMGB1 and the regulation of miR-218 on the HMGB1-mediated cell autophagy during chemotherapy resistance in endometrial carcinoma cells. These results reveal novel potential role of miR-218 against chemotherapy resistance during the treatment of endometrial carcinoma.

Comparison of laboratory single species and field population-level effects of the pyrethroid insecticide lambda-cyhalothrin on freshwater invertebrates.

PubMed

Schroer, A F W; Belgers, J D M; Brock, T C M; Matser, A M; Maund, S J; Van den Brink, P J

2004-04-01

The toxicity of the pyrethroid insecticide lambda-cyhalothrin to freshwater invertebrates has been investigated using data from short-term laboratory toxicity tests and in situ bioassays and population-level effects in field microcosms. In laboratory tests, patterns of toxicity were consistent with previous data on pyrethroids. The midge Chaoborus obscuripes was most sensitive (48- and 96-h EC50 = 2.8 ng/L). Other insect larvae (Hemiptera, Ephemeroptera) and macrocrustacea (Amphipoda, Isopoda) were also relatively sensitive, with 48- and 96-h EC50 values between 10 and 100 ng/L. Generally, microcrustacea (Cladocera, Copepoda) and larvae of certain insect groups (Odonata and Chironomidae) were less sensitive, with 48-h EC50 values higher than 100 ng/L. Mollusca and Plathelminthes were insensitive and were unaffected at concentrations at and above the water solubility (5 microg/L). Generally, the EC50 values based on initial population responses in field enclosures were similar to values derived from laboratory tests with the same taxa. Also, the corresponding fifth and tenth percentile hazard concentrations (HC5 and HC10) were similar (laboratory HC5 = 2.7 ng/L and field HC5 = 4.1 ng/L; laboratory and field HC10 = 5.1 ng/L), at least when based on the same sensitive taxonomic groups (insects and crustaceans) and when a similar concentration range was taken into account. In the three field enclosure experiments and at a treatment level of 10 ng/L, consistent effects were observed for only one population (Chaoborus obscuripes), with recovery taking place within 3 to 6 weeks. The laboratory HC5 (2.7 ng/L) and HC10 (5.1 ng/L) based on acute EC50 values of all aquatic arthropod taxa were both lower than this 10 ng/L, a concentration that might represent the "regulatory acceptable concentration." The HC5 and HC10 values in this study in The Netherlands (based on static laboratory tests with freshwater arthropods) were very similar to those derived from a previous study in the United Kingdom (1.4 and 3.3 ng/L). This suggests that for pesticides like lambda-cyhalothrin, HC5 values based on static laboratory tests may provide a conservative estimate of the potential for community-level effects under field conditions. While these HC5 values are conservative for initial effects, they do not provide information on recovery potential, which may be important for regulatory decision-making.

INVENTORY AND ASSESSMENT OF CLIMATE SENSITIVE DECISIONS

EPA Science Inventory

The project will create a pilot inventory of climate-sensitive resource managment decision. The project will develop and demonstrate a new approach to collecting systematic information about the context and characteristics of climate-sensitive decisions and using this informatio...

1.13 – Emerging contaminants

USGS Publications Warehouse

Barber, Larry B.

2014-01-01

Since the Industrial Revolution, a diversity of large-scale chemical innovations has impacted aquatic systems in urban environments. Beginning in the 1990s, there has been a growing scientific interest and public awareness of the effects of the chemicals used in domestic, commercial, industrial, and agricultural applications, referred to in this article as ‘emerging contaminants’ (ECs), on ecosystem and human health. The growing global population and its increasing demands on water supplies in conjunction with climate-induced changes in hydrologic regimes place stress on freshwater resources, resulting in a greater reliance on reuse of reclaimed municipal wastewater treatment plant (WWTP) effluents to meet human and environmental needs. WWTP effluents are a major source of ECs, and it is important to have an understanding of the chemical composition of the reclaimed water, because many ECs are biologically active and the effects of chronic exposure to low concentration complex mixtures are unknown. Several classes of ECs that have been shown to be widespread in the aquatic environment are discussed in this chapter, including surfactants, complexing agents, fragrances, antimicrobials, industrial chemicals, pharmaceuticals, natural and synthetic estrogens, and disinfection byproducts. All of these compounds are biologically active via a variety of modes of action, and can occur in aquatic systems at concentrations ranging from <0.001 to >100 μg l−1.

Emission factors of atmospheric and climatic pollutants from crop residues burning.

PubMed

Santiago-De La Rosa, Naxieli; González-Cardoso, Griselda; Figueroa-Lara, José de Jesús; Gutiérrez-Arzaluz, Mirella; Octaviano-Villasana, Claudia; Ramírez-Hernández, Irma Fabiola; Mugica-Álvarez, Violeta

2018-04-13

Biomass burning is a common agricultural practice, because it allows elimination of postharvesting residues; nevertheless, it involves an inefficient combustion process that generates atmospheric pollutants emission, which has implications on health and climate change. This work focuses on the estimation of emission factors (EFs) of PM 2.5 , PM 10 , organic carbon (OC), elemental carbon (EC), carbon monoxide (CO), carbon dioxide (CO 2 ), and methane (CH 4 ) of residues from burning alfalfa, barley, beans, cotton, maize, rice, sorghum, and wheat in Mexico. Chemical characteristics of the residues were determined to establish their relationship with EFs, as well as with the modified combustion efficiency (MCE). Essays were carried out in an open combustion chamber with isokinetic sampling, following modified EPA 201-A method. EFs did not present statistical differences among different varieties of the same crop, but were statistically different among different crops, showing that generic values of EFs for all the agricultural residues can introduce significant uncertainties when used for climatic and atmospheric pollutant inventories. EFs of PM 2.5 ranged from 1.19 to 11.30 g kg -1 , and of PM 10 from 1.77 to 21.56 g kg -1 . EFs of EC correlated with lignin content, whereas EFs of OC correlated inversely with carbon content. EFs of EC and OC in PM 2.5 ranged from 0.15 to 0.41 g kg -1 and from 0.33 to 5.29 g kg -1 , respectively, and in PM 10 , from 0.17 to 0.43 g kg -1 and from 0.54 to 11.06 g kg -1 . CO 2 represented the largest gaseous emissions volume with 1053.35-1850.82 g kg -1 , whereas the lowest was CH 4 with 1.61-5.59 g kg -1 . CO ranged from 28.85 to 155.71 g kg -1 , correlating inversely with carbon content and MCE. EFs were used to calculate emissions from eight agricultural residues burning in the country during 2016, to know the potential mitigation of climatic and atmospheric pollutants, provided this practice was banned. The emission factors of particles, short-lived climatic pollutants, and atmospheric pollutants from the crop residues burning of eight agricultural wastes crops, determined in this study using a standardized method, provides better knowledge of the emissions of those species in Latin America and other developing countries, and can be used as inputs in air quality models and climatic studies. The EFs will allow the development of more accurate inventories of aerosols and gaseous pollutants, which will lead to the design of effective mitigation strategies and planning processes for sustainable agriculture.

The Impact of Microgravity and Hypergravity on Endothelial Cells

PubMed Central

Maier, Jeanette A. M.

2015-01-01

The endothelial cells (ECs), which line the inner surface of vessels, play a fundamental role in maintaining vascular integrity and tissue homeostasis, since they regulate local blood flow and other physiological processes. ECs are highly sensitive to mechanical stress, including hypergravity and microgravity. Indeed, they undergo morphological and functional changes in response to alterations of gravity. In particular microgravity leads to changes in the production and expression of vasoactive and inflammatory mediators and adhesion molecules, which mainly result from changes in the remodelling of the cytoskeleton and the distribution of caveolae. These molecular modifications finely control cell survival, proliferation, apoptosis, migration, and angiogenesis. This review summarizes the state of the art on how microgravity and hypergravity affect cultured ECs functions and discusses some controversial issues reported in the literature. PMID:25654101

The impact of microgravity and hypergravity on endothelial cells.

PubMed

Maier, Jeanette A M; Cialdai, Francesca; Monici, Monica; Morbidelli, Lucia

2015-01-01

The endothelial cells (ECs), which line the inner surface of vessels, play a fundamental role in maintaining vascular integrity and tissue homeostasis, since they regulate local blood flow and other physiological processes. ECs are highly sensitive to mechanical stress, including hypergravity and microgravity. Indeed, they undergo morphological and functional changes in response to alterations of gravity. In particular microgravity leads to changes in the production and expression of vasoactive and inflammatory mediators and adhesion molecules, which mainly result from changes in the remodelling of the cytoskeleton and the distribution of caveolae. These molecular modifications finely control cell survival, proliferation, apoptosis, migration, and angiogenesis. This review summarizes the state of the art on how microgravity and hypergravity affect cultured ECs functions and discusses some controversial issues reported in the literature.

Importance of ensembles in projecting regional climate trends

NASA Astrophysics Data System (ADS)

Arritt, Raymond; Daniel, Ariele; Groisman, Pavel

2016-04-01

We have performed an ensemble of simulations using RegCM4 to examine the ability to reproduce observed trends in precipitation intensity and to project future changes through the 21st century for the central United States. We created a matrix of simulations over the CORDEX North America domain for 1950-2099 by driving the regional model with two different global models (HadGEM2-ES and GFDL-ESM2M, both for RCP8.5), by performing simulations at both 50 km and 25 km grid spacing, and by using three different convective parameterizations. The result is a set of 12 simulations (two GCMs by two resolutions by three convective parameterizations) that can be used to systematically evaluate the influence of simulation design on predicted precipitation. The two global models were selected to bracket the range of climate sensitivity in the CMIP5 models: HadGEM2-ES has the highest ECS of the CMIP5 models, while GFDL-ESM2M has one of the lowestt. Our evaluation metrics differ from many other RCM studies in that we focus on the skill of the models in reproducing past trends rather than the mean climate state. Trends in frequency of extreme precipitation (defined as amounts exceeding 76.2 mm/day) for most simulations are similar to the observed trend but with notable variations depending on RegCM4 configuration and on the driving GCM. There are complex interactions among resolution, choice of convective parameterization, and the driving GCM that carry over into the future climate projections. We also note that biases in the current climate do not correspond to biases in trends. As an example of these points the Emanuel scheme is consistently "wet" (positive bias in precipitation) yet it produced the smallest precipitation increase of the three convective parameterizations when used in simulations driven by HadGEM2-ES. However, it produced the largest increase when driven by GFDL-ESM2M. These findings reiterate that ensembles using multiple RCM configurations and driving GCMs are essential for projecting regional climate change, even when a single RCM is used. This research was sponsored by the U.S. Department of Agriculture National Institute of Food and Agriculture.

Assessing and correcting spatial representativeness of tower eddy-covariance flux measurements

NASA Astrophysics Data System (ADS)

Metzger, S.; Xu, K.; Desai, A. R.; Taylor, J. R.; Kljun, N.; Blanken, P.; Burns, S. P.; Scott, R. L.

2014-12-01

Estimating the landscape-scale exchange of ecologically relevant trace gas and energy fluxes from tower eddy-covariance (EC) measurements is often complicated by surface heterogeneity. For example, a tower EC measurement may represent less than 1% of a grid cell resolved by mechanistic models (order 100-1000 km2). In particular for data assimilation or comparison with large-scale observations, it is hence critical to assess and correct the spatial representativeness of tower EC measurements. We present a procedure that determines from a single EC tower the spatio-temporally explicit flux field of its surrounding. The underlying principle is to extract the relationship between biophysical drivers and ecological responses from measurements under varying environmental conditions. For this purpose, high-frequency EC flux processing and source area calculations (≈60 h-1) are combined with remote sensing retrievals of land surface properties and subsequent machine learning. Methodological details are provided in our companion presentation "Towards the spatial rectification of tower-based eddy-covariance flux observations". We apply the procedure to one year of data from each of four AmeriFlux sites under different climate and ecological environments: Lost Creek shrub fen wetland, Niwot Ridge subalpine conifer, Park Falls mixed forest, and Santa Rita mesquite savanna. We find that heat fluxes from the Park Falls 122-m-high EC measurement and from a surrounding 100 km2 target area differ up to 100 W m-2, or 65%. Moreover, 85% and 24% of the EC flux observations are adequate surrogates of the mean surface-atmosphere exchange and its spatial variability across a 900 km2 target area, respectively, at 5% significance and 80% representativeness levels. Alternatively, the resulting flux grids can be summarized as probability density functions, and used to inform mechanistic models directly with the mean flux value and its spatial variability across a model grid cell. Lastly, for each site we evaluate the applicability of the procedure based on a full bottom-up uncertainty budget.

Year-round Source Contributions of Fossil Fuel and Biomass Combustion to Elemental Carbon on the North Slope Alaska Utilizing Radiocarbon Analysis

NASA Astrophysics Data System (ADS)

Barrett, T. E.; Gustafsson, O.; Winiger, P.; Moffett, C.; Back, J.; Sheesley, R. J.

2015-12-01

It is well documented that the Arctic has undergone rapid warming at an alarming rate over the past century. Black carbon (BC) affects the radiative balance of the Arctic directly and indirectly through the absorption of incoming solar radiation and by providing a source of cloud and ice condensation nuclei. Among atmospheric aerosols, BC is the most efficient absorber of light in the visible spectrum. The solar absorbing efficiency of BC is amplified when it is internally mixed with sulfates. Furthermore, BC plumes that are fossil fuel dominated have been shown to be approximately 100% more efficient warming agents than biomass burning dominated plumes. The renewal of offshore oil and gas exploration in the Arctic, specifically in the Chukchi Sea, will introduce new BC sources to the region. This study focuses on the quantification of fossil fuel and biomass combustion sources to atmospheric elemental carbon (EC) during a year-long sampling campaign in the North Slope Alaska. Samples were collected at the Department of Energy Atmospheric Radiation Measurement (ARM) climate research facility in Barrow, AK, USA. Particulate matter (PM10) samples collected from July 2012 to June 2013 were analyzed for EC and sulfate concentrations combined with radiocarbon (14C) analysis of the EC fraction. Radiocarbon analysis distinguishes fossil fuel and biomass burning contributions based on large differences in end members between fossil and contemporary carbon. To perform isotope analysis on EC, it must be separated from the organic carbon fraction of the sample. Separation was achieved by trapping evolved CO2 produced during EC combustion in a cryo-trap utilizing liquid nitrogen. Radiocarbon results show an average fossil contribution of 85% to atmospheric EC, with individual samples ranging from 47% to 95%. Source apportionment results will be combined with back trajectory (BT) analysis to assess geographic source region impacts on the EC burden in the western Arctic.

Decoupling peroxyacetyl nitrate from ozone in Chinese outflows observed at Gosan Climate Observatory

NASA Astrophysics Data System (ADS)

Han, Jihyun; Lee, Meehye; Shang, Xiaona; Lee, Gangwoong; Emmons, Louisa K.

2017-09-01

We measured peroxyacetyl nitrate (PAN) and other reactive species such as O3, NO2, CO, and SO2 with aerosols including mass, organic carbon (OC), and elemental carbon (EC) in PM2. 5 and K+ in PM1. 0 at Gosan Climate Observatory in Korea (33.17° N, 126.10° E) during 19 October-6 November 2010. PAN was determined through fast gas chromatography with luminol chemiluminescence detection at 425 nm every 2 min. The PAN mixing ratios ranged from 0.1 (detection limit) to 2.4 ppbv with a mean of 0.6 ppbv. For all measurements, PAN was unusually better correlated with PM2. 5 (Pearson correlation coefficient, γ = 0.79) than with O3 (γ = 0.67). In particular, the O3 level was highly elevated with SO2 at midnight, along with a typical midday peak when air was transported rapidly from the Beijing areas. The PAN enhancement was most noticeable during the occurrence of haze under stagnant conditions. In Chinese outflows slowly transported over the Yellow Sea, PAN gradually increased up to 2.4 ppbv at night, in excellent correlation with a concentration increase in PM2. 5 OC and EC, PM2. 5 mass, and PM1. 0 K+. The high K+ concentration and OC / EC ratio indicated that the air mass was impacted by biomass combustion. This study highlights PAN decoupling with O3 in Chinese outflows and suggests PAN as a useful indicator for diagnosing continental outflows and assessing their perturbation of regional air quality in northeast Asia.

Endothelial Microparticles From Acute Coronary Syndrome Patients Induce Premature Coronary Artery Endothelial Cell Aging and Thrombogenicity: Role of the Ang II/AT1 Receptor/NADPH Oxidase-Mediated Activation of MAPKs and PI3-Kinase Pathways.

PubMed

Abbas, Malak; Jesel, Laurence; Auger, Cyril; Amoura, Lamia; Messas, Nathan; Manin, Guillaume; Rumig, Cordula; León-González, Antonio J; Ribeiro, Thais P; Silva, Grazielle C; Abou-Merhi, Raghida; Hamade, Eva; Hecker, Markus; Georg, Yannick; Chakfe, Nabil; Ohlmann, Patrick; Schini-Kerth, Valérie B; Toti, Florence; Morel, Olivier

2017-01-17

Microparticles (MPs) have emerged as a surrogate marker of endothelial dysfunction and cardiovascular risk. This study examined the potential of MPs from senescent endothelial cells (ECs) or from patients with acute coronary syndrome (ACS) to promote premature EC aging and thrombogenicity. Primary porcine coronary ECs were isolated from the left circumflex coronary artery. MPs were prepared from ECs and venous blood from patients with ACS (n=30) and from healthy volunteers (n=4) by sequential centrifugation. The level of endothelial senescence was assessed as senescence-associated β-galactosidase activity using flow cytometry, oxidative stress using the redox-sensitive probe dihydroethidium, tissue factor activity using an enzymatic Tenase assay, the level of target protein expression by Western blot analysis, platelet aggregation using an aggregometer, and shear stress using a cone-and-plate viscometer. Senescence, as assessed by senescence-associated β-galactosidase activity, was induced by the passaging of porcine coronary artery ECs from passage P1 to P4, and was associated with a progressive shedding of procoagulant MPs. Exposure of P1 ECs to MPs shed from senescent P3 cells or circulating MPs from ACS patients induced increased senescence-associated β-galactosidase activity, oxidative stress, early phosphorylation of mitogen-activated protein kinases and Akt, and upregulation of p53, p21, and p16. Ex vivo, the prosenescent effect of circulating MPs from ACS patients was evidenced only under conditions of low shear stress. Depletion of endothelial-derived MPs from ACS patients reduced the induction of senescence. Prosenescent MPs promoted EC thrombogenicity through tissue factor upregulation, shedding of procoagulant MPs, endothelial nitric oxide synthase downregulation, and reduced nitric oxide-mediated inhibition of platelet aggregation. These MPs exhibited angiotensin-converting enzyme activity and upregulated AT1 receptors and angiotensin-converting enzyme in P1 ECs. Losartan, an AT1 receptor antagonist, and inhibitors of either mitogen-activated protein kinases or phosphoinositide 3-kinase prevented the MP-induced endothelial senescence. These findings indicate that endothelial-derived MPs from ACS patients induce premature endothelial senescence under atheroprone low shear stress and thrombogenicity through angiotensin II-induced redox-sensitive activation of mitogen-activated protein kinases and phosphoinositide 3-kinase/Akt. They further suggest that targeting endothelial-derived MP shedding and their bioactivity may be a promising therapeutic strategy to limit the development of an endothelial dysfunction post-ACS. © 2016 American Heart Association, Inc.

Comparison of the anti-scorbutic activity of L-ascorbic acid and Ester C in the non-ascorbate synthesizing Osteogenic Disorder Shionogi (ODS) rat.

PubMed

Verlangieri, A J; Fay, M J; Bannon, A W

1991-01-01

The Osteogenic Disorder Shionogi (ODS) rat, Clea Inc., Tokyo, Japan lacks the ability to synthesize L-ascorbic acid (AA). As with man, monkey and the guinea pig, this rat lacks L-gulonolactone oxidase necessary for the synthesis of AA from glucose. This study shows this animal to be an alternative to the guinea pig in AA studies. The anti-scorbutic potency of Ester C (EC), a calcium ascorbate and calcium threonate mixture, was compared with an AA dose of equal ascorbate activity equivalents (AAE) for anti-scorbutic activity in the ODS rat. The minimal anti-scorbutic dose of EC was determined to be 0.44 mg/kg/day (AAE), while an AA dose of 0.51 mg/kg/day (AAE) was not anti-scorbutic in a 24 day study. At 24 days EC rats gained 125% of initial body weight (BW) and the AA rats only 45% BW. Scorbutic signs at 24 days were scored on a 0 (min) to 3 (max) scale. The EC/AA ratio scores were: hemorrhage 0/1.4, behavior change 0/2.0, piloerection 0/2.2, mobility 0.4/2.2, dysbasia 0.6/2.8 and ataxia 0.4/1.0. Pearson's correlation coefficient for BW versus AAE was r = .34 for the AA group and r = .90 for the EC group. The morbidity index for EC was 0/5 and for the AA group 2/5. The AAE dose of AA which was 16% higher/day than the EC AAE dose was not anti-scorbutic, while the EC dose was anti-scorbutic. EC rats had 3.5X greater weight gain, a sensitive indicator of scurvy, than the AA rats. EC rats had 3-4 times less, if any, scorbutic signs than AA rats. The results clearly show that, based on ascorbate activity equivalents, EC has more available ascorbate activity/potency than AA. The mechanism of this increased potency is believed to be due to the facilitated transport of AAE into the cell by the threonate (a normal in vivo metabolite of AA) present in the EC product. In addition, previous studies have shown EC (AAE) to be higher in plasma and excreted less rapidly than the AAE derived from AA administered orally.

What do parents know about their children's comprehension of emotions? accuracy of parental estimates in a community sample of pre-schoolers.

PubMed

Kårstad, S B; Kvello, O; Wichstrøm, L; Berg-Nielsen, T S

2014-05-01

Parents' ability to correctly perceive their child's skills has implications for how the child develops. In some studies, parents have shown to overestimate their child's abilities in areas such as IQ, memory and language. Emotion Comprehension (EC) is a skill central to children's emotion regulation, initially learned from their parents. In this cross-sectional study we first tested children's EC and then asked parents to estimate the child's performance. Thus, a measure of accuracy between child performance and parents' estimates was obtained. Subsequently, we obtained information on child and parent factors that might predict parents' accuracy in estimating their child's EC. Child EC and parental accuracy of estimation was tested by studying a community sample of 882 4-year-olds who completed the Test of Emotion Comprehension (TEC). The parents were instructed to guess their children's responses on the TEC. Predictors of parental accuracy of estimation were child actual performance on the TEC, child language comprehension, observed parent-child interaction, the education level of the parent, and child mental health. Ninety-one per cent of the parents overestimated their children's EC. On average, parents estimated that their 4-year-old children would display the level of EC corresponding to a 7-year-old. Accuracy of parental estimation was predicted by child high performance on the TEC, child advanced language comprehension, and more optimal parent-child interaction. Parents' ability to estimate the level of their child's EC was characterized by a substantial overestimation. The more competent the child, and the more sensitive and structuring the parent was interacting with the child, the more accurate the parent was in the estimation of their child's EC. © 2013 John Wiley & Sons Ltd.

Enhanced endothelial cell senescence by lithium-induced matrix metalloproteinase-1 expression.

PubMed

Struewing, Ian T; Durham, Samuel N; Barnett, Corey D; Mao, Catherine D

2009-06-26

Endothelial cell (EC) senescence and dysfunction occurring after chronic injury and inflammation are highly associated with the development and progression of cardiovascular diseases. However, the factors involved in the establishment of EC senescence remain poorly understood. We have previously shown that lithium, an inhibitor of glycogen synthase kinase (GSK)-3beta and activator of the Wnt/beta-catenin signaling pathway, induces an EC senescent-like phenotype. Herein, we show that lithium induces a rapid and pronounced up-regulation of the matrix metalloproteinase (MMP)-1, an inflammation and senescent cell marker, at the mRNA and protein levels, whereas the induction of two other senescent cell markers is either weak (interleukin-8) or delayed (plasminogen activator inhibitor-1). Lithium effect on MMP-1 expression is also specific among other MMPs and not mediated by GSK3beta inhibition. Lithium affects MMP-1 expression mainly at the transcriptional level but neither the AP1/Ets regulatory sites nor the redox sensitive (-1607/2G) site in MMP-1 promoter are involved in lithium-dependent MMP-1 regulation. However, down-regulation of p53, a target of lithium in EC, dampens both basal and lithium-induced MMP-1 expression, which further links MMP-1 up-regulation with the establishment of cell senescence. Although increased MMP-1 levels are usually associated with angiogenesis in enabled proliferative EC, the exogenous addition of activated MMP-1 on lithium- arrested EC increases the number of EC positive for the senescent-associated-beta-galactosidase marker. Conversely, down-regulation of MMP-1 expression by small interfering RNAs blunts the lithium-dependent increase in senescent-associated-beta-galactosidase positive cells. Altogether our data indicate that lithium-induced MMP-1 may participate in the reinforcement of EC senescence and reveal a novel mechanism for lithium-induced tissue remodeling.

Assessing single and joint toxicity of three phenylurea herbicides using Lemna minor and Vibrio fischeri bioassays.

PubMed

Gatidou, Georgia; Stasinakis, Athanasios S; Iatrou, Evangelia I

2015-01-01

Single and joint toxicity of three substituted urea herbicides, namely monolinuron [3-(4-chlorophenyl)-1-methoxy-1-methylurea], linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] and diuron [1-(3,4 dichlorophenyl)-3,3 dimethyl urea], were studied. The duckweed Lemna minor and the luminescent bacterium Vibrio fischeri were used for the toxicity assessment and they were exposed to various concentrations of the herbicides, individually and in binary mixtures. The exposure time was 7d for the duckweed and 30 min for the bacterium. Estimation of EC50 values was performed by frond counting and reduction in light output for Lemna minor and Vibrio fischeri, respectively. Lemna minor was found to be much more sensitive than Vibrio fischeri to target compounds. The toxicity of the three herbicides applied solely was estimated to be in decreasing order: diuron (EC50=28.3 μg L(-1))≈linuron (EC50=30.5 μg L(-1))>monolinuron (EC50=300 μg L(-1)) for the duckweed and linuron (EC50=8.2 mg L(-1))>diuron (EC50=9.2 mg L(-1))>monolinuron (EC50=11.2 mg L(-1)) for the bacterium. Based on the environmental concentrations reported in the literature and EC50 values obtained from Lemna minor experiments, Risk Quotients (RQ) much higher than 1 were calculated for diuron and linuron. In Lemna minor experiments, combination of target compounds resulted to additive effects due to their same mode of phenylurea action on photosynthetic organisms. Regarding Vibrio fischeri, synergistic, additive and antagonistic effects were observed, which varied according to the concentrations of target compounds. Copyright © 2014 Elsevier Ltd. All rights reserved.

An early warning system for high climate sensitivity? (Invited)

NASA Astrophysics Data System (ADS)

Pierrehumbert, R.

2010-12-01

The scientific case for the clear and present danger of global warming has been unassailable at least since the release of the Charney Report more than thirty years ago, if not longer. While prompt action to begin decarbonizing energy systems could still head off much of the potential warming, it is distinctly possible that emissions will continue unabated in the coming decades, leading to a doubling or more of pre-industrial carbon dioxide concentrations. At present, we are in the unenviable position of not even knowing how bad things will get if this scenario comes to pass, because of the uncertainty in climate sensitivity. If climate sensitivity is high, then the consequences will be dire, perhaps even catastrophic. As the world continues to warm in response to continued carbon dioxide emissions, will we at least be able to monitor the climate and provide an early warning that the planet is on a high-sensitivity track, if such turns out to be the case? At what point will we actually know the climate sensitivity? It has long been recognized that the prime contributor to uncertainty in climate sensitivity is uncertainty in cloud feedbacks. Study of paleoclimate and climate of the past century has not been able to resolve which models do cloud feedback most correctly, because of uncertainties in radiative forcing. In this talk, I will discuss monitoring requirements, and analysis techniques, that might have the potential to determine which climate models most faithfully represent climate feedbacks, and thus determine which models provide the best estimate of climate sensitivity. The endeavor is complicated by the distinction between transient climate response and equilibrium climate sensitivity. I will discuss the particular challenges posed by this issue, particularly in light of recent indications that the pattern of ocean heat storage may lead to different cloud feedbacks in the transient warming stage than apply once the system has reached equilibrium. Apart from this problem, the transient nature of climate response driven by increasing CO2 requires careful monitoring of ocean heat storage as well as top-of-atmosphere radiative budgets, if climate sensitivity is to be estimated. Water vapor feedback is not considered as uncertain as cloud feedback, but there is still a considerable potential for surprises. I will discuss microwave monitoring requirements for tracking water vapor feedback. At the other extreme, the longer term feedbacks that contribute to Earth System Sensitivity are even more uncertain than cloud feedbacks, particularly with regard to the terrestrial carbon cycle. Prospects for obtaining an early warning of a PETM-type organic carbon release seem bleak. Finally, I will discuss the particular challenge of obtaining an early warning of high climate sensitivity in the case that the climate system has a bifurcation.

Acute sensitivity of a broad range of freshwater mussels to chemicals with different modes of toxic action

USGS Publications Warehouse

Wang, Ning; Ivey, Chris D.; Ingersoll, Christopher G.; Brumbaugh, William G.; Alvarez, David; Hammer, Edward J.; Bauer, Candice R.; Augspurger, Tom; Raimondo, Sandy; Barnhart, M.Christopher

2017-01-01

Freshwater mussels, one of the most imperiled groups of animals in the world, are generally underrepresented in toxicity databases used for the development of ambient water quality criteria and other environmental guidance values. Acute 96-h toxicity tests were conducted to evaluate the sensitivity of 5 species of juvenile mussels from 2 families and 4 tribes to 10 chemicals (ammonia, metals, major ions, and organic compounds) and to screen 10 additional chemicals (mainly organic compounds) with a commonly tested mussel species, fatmucket (Lampsilis siliquoidea). In the multi-species study, median effect concentrations (EC50s) among the 5 species differed by a factor of ≤2 for chloride, potassium, sulfate, and zinc; a factor of ≤5 for ammonia, chromium, copper, and nickel; and factors of 6 and 12 for metolachlor and alachlor, respectively, indicating that mussels representing different families or tribes had similar sensitivity to most of the tested chemicals, regardless of modes of action. There was a strong linear relationship between EC50s for fatmucket and the other 4 mussel species across the 10 chemicals (r2 = 0.97, slope close to 1.0), indicating that fatmucket was similar to other mussel species; thus, this commonly tested species can be a good surrogate for protecting other mussels in acute exposures. The sensitivity of juvenile fatmucket among different populations or cultured from larvae of wild adults and captive-cultured adults was also similar in acute exposures to copper or chloride, indicating captive-cultured adult mussels can reliably be used to reproduce juveniles for toxicity testing. In compiled databases for all freshwater species, 1 or more mussel species were among the 4 most sensitive species for alachlor, ammonia, chloride, potassium, sulfate, copper, nickel, and zinc; therefore, the development of water quality criteria and other environmental guidance values for these chemicals should reflect the sensitivity of mussels. In contrast, the EC50s of fatmucket tested in the single-species study were in the high percentiles (>75th) of species sensitivity distributions for 6 of 7 organic chemicals, indicating mussels might be relatively insensitive to organic chemicals in acute exposures.

Species-specific sensitivity to selenium-induced impairment of cortisol secretion in adrenocortical cells of rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, L.L., E-mail: lana.miller@uleth.ca; Hontela, A.

Species differences in physiological and biochemical attributes exist even among closely related species and may underlie species-specific sensitivity to toxicants. Rainbow trout (RT) are more sensitive than brook trout (BT) to the teratogenic effects of selenium (Se), but it is not known whether all tissues exhibit this pattern of vulnerability. In this study, primary cultures of RT and BT adrenocortical cells were exposed to selenite (Na{sub 2}SO{sub 3}) and selenomethionine (Se-Met) to compare cell viability and ACTH-stimulated cortisol secretion in the two fish species. Cortisol, the primary stress hormone in fish, facilitates maintenance of homeostasis when fish are exposed tomore » stressors, including toxicants. Cell viability was not affected by Se, but selenite impaired cortisol secretion, while Se-Met did not (RT and BT EC{sub 50} > 2000 mg/L). RT cells were more sensitive (EC{sub 50} = 8.7 mg/L) to selenite than BT cells (EC{sub 50} = 90.4 mg/L). To identify the targets where Se disrupts cortisol synthesis, selenite-impaired RT and BT cells were stimulated with ACTH, dbcAMP, OH-cholesterol, and pregnenolone. Selenite acted at different steps in the cortisol biosynthesis pathway in RT and BT cells, confirming a species-specific toxicity mechanism. To test the hypothesis that oxidative stress mediates Se-induced toxicity, selenite-impaired RT cells were exposed to NAC, BSO and antioxidants (DETCA, ATA, Vit A, and Vit E). Inhibition of SOD by DETCA enhanced selenite-induced cortisol impairment, indicating that oxidative stress plays a role in Se toxicity; however, modifying GSH content of the cells did not have an effect. The results of this study, with two closely related salmonids, provided additional evidence for species-specific differences in sensitivity to Se which should be considered when setting thresholds and water quality guidelines. - Research Highlights: > We investigated species-specific sensitivity to Se in trout adrenocortical cells. > Selenite, not Se-Met, disrupts cortisol secretion in trout adrenocortical cells. > Rainbow trout cells are more sensitive than brook trout cells to selenite toxicity. > Superoxide dismutase may protect adrenocortical cells from selenite toxicity.« less

Modulation of neuronal sodium channels by the sea anemone peptide BDS-I

PubMed Central

Liu, Pin; Jo, Sooyeon

2012-01-01

Blood-depressing substance I (BDS-I), a 43 amino-acid peptide from sea anemone venom, is used as a specific inhibitor of Kv3-family potassium channels. We found that BDS-I acts with even higher potency to modulate specific types of voltage-dependent sodium channels. In rat dorsal root ganglion (DRG) neurons, 3 μM BDS-I strongly enhanced tetrodotoxin (TTX)-sensitive sodium current but weakly inhibited TTX-resistant sodium current. In rat superior cervical ganglion (SCG) neurons, which express only TTX-sensitive sodium current, BDS-I enhanced current elicited by small depolarizations and slowed decay of currents at all voltages (EC50 ∼ 300 nM). BDS-I acted with exceptionally high potency and efficacy on cloned human Nav1.7 channels, slowing inactivation by 6-fold, with an EC50 of approximately 3 nM. BDS-I also slowed inactivation of sodium currents in N1E-115 neuroblastoma cells (mainly from Nav1.3 channels), with an EC50 ∼ 600 nM. In hippocampal CA3 pyramidal neurons (mouse) and cerebellar Purkinje neurons (mouse and rat), BDS-I had only small effects on current decay (slowing inactivation by 20–50%), suggesting relatively weak sensitivity of Nav1.1 and Nav1.6 channels. The biggest effect of BDS-I in central neurons was to enhance resurgent current in Purkinje neurons, an effect reflected in enhancement of sodium current during the repolarization phase of Purkinje neuron action potentials. Overall, these results show that BDS-I acts to modulate sodium channel gating in a manner similar to previously known neurotoxin receptor site 3 anemone toxins but with different isoform sensitivity. Most notably, BDS-I acts with very high potency on human Nav1.7 channels. PMID:22442564

Comparison of outcomes obtained in murine local lymph node assays using CBA/J or CBA/Ca mice.

PubMed

Maeda, Yosuke; Hirosaki, Haruka; Yakata, Naoaki; Takeyoshi, Masahiro

2016-08-01

CBA/J and CBA/Ca mice are the recommended strains for local lymph node assays (LLNAs). Here, we report quantitative and qualitative comparisons between both mouse strains to provide useful information for the strain selection of sensitization testing. LLNA was conducted, in accordance with Organisation for Economic Co-operation and Development Test Guideline No. 429, with CBA/J and CBA/Ca mice using five chemicals including typical contact sensitizers and non-sensitizers: 2,4-dinitrochlorobenzene (DNCB), isoeugenol, α-hexylcinnamic aldehyde (HCA), propylene glycol (PG), and hexane; then outcomes were compared based on the raw data (disintegrations per minute, DPM), stimulation index (SI) values, EC3 values and positive/negative decisions. Although a significant difference was noted between DPM values derived from each strain of mice, SI values exhibited no considerable difference. The EC3 values for DNCB in CBA/J and CBA/Ca mice were 0.04 and 0.03, those for isoeugenol were 1.4 and 0.9, and those for HCA were 7.7 and 6.0, respectively. All EC values derived from each test system were almost equivalent and were within the range of acceptance criteria of the ICCVAM performance standard for LLNA. Positive/negative outcomes for all test chemicals were consistent. In conclusion, no considerable differences were observed in the final outcomes derived from CBA/J and CBA/Ca mice in LLNA. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Activities of Jatropha curcas phorbol esters in various bioassays.

PubMed

Devappa, Rakshit K; Rajesh, Sanjay K; Kumar, Vikas; Makkar, Harinder P S; Becker, Klaus

2012-04-01

Jatropha curcas seeds contain 30-35% oil, which can be converted to high quality biodiesel. However, Jatropha oil is toxic, ascribed to the presence of phorbol esters (PEs). In this study, isolated phorbol ester rich fraction (PEEF) was used to evaluate the activity of PEs using three aquatic species based bioassays (snail (Physa fontinalis), brine shrimp (Artemeia salina), daphnia (Daphnia magna)) and microorganisms. In all the bioassays tested, increase in concentration of PEs increased mortality with an EC(50) (48 h) of 0.33, 26.48 and 0.95 mg L(-1) PEs for snail, artemia and daphnia, respectively. The sensitivity of various microorganisms for PEs was also tested. Among the bacterial species tested, Streptococcus pyogenes and Proteus mirabilis were highly susceptible with a minimum inhibitory concentration (MIC) of 215 mg L(-1) PEs; and Pseudomonas putida were also sensitive with MIC of 251 mg L(-1) PEs. Similarly, Fusarium species of fungi exhibited EC(50) of 58 mg L(-1) PEs, while Aspergillus niger and Curvularia lunata had EC(50) of 70 mg L(-1). The snail bioassay was most sensitive with 100% snail mortality at 1 μg of PEs mL(-1). In conclusion, snail bioassay could be used to monitor PEs in Jatropha derived products such as oil, biodiesel, fatty acid distillate, kernel meal, cake, glycerol or for contamination in soil or other environmental matrices. In addition, PEs with molluscicidal/antimicrobial activities could be utilized for agricultural and pharmaceutical applications. Copyright © 2011 Elsevier Inc. All rights reserved.

High-resolution spectral analysis of ammonia near 6.2 μm using a cw EC-QCL coupled with cavity ring-down spectroscopy.

PubMed

Maithani, Sanchi; Mandal, Santanu; Maity, Abhijit; Pal, Mithun; Pradhan, Manik

2018-04-30

We report on the development of a mid-infrared cavity ring-down spectrometer (CRDS) coupled with a continuous wave (cw) external cavity quantum cascade laser (EC-QCL), operating between 6.0 μm and 6.3 μm, for high-resolution spectroscopic studies of ammonia (NH3) which served as a bench-mark molecule in this spectral region. We characterized the EC-QCL based CRDS system in detail and achieved a noise-equivalent absorption (NEA) coefficient of 2.11 × 10-9 cm-1 Hz-1/2 for a 100 Hz data acquisition rate. We thereafter exploited the system for high-resolution spectroscopic analysis of interference-free 10 transition lines of the ν4 fundamental vibrational band of NH3 centred at ∼6.2 μm. We probed the strongest interference-free absorption line RQ(4,3) of ν4, centred at 1613.370 cm-1 for highly-sensitive trace detection of NH3 and subsequently achieved a minimum detection sensitivity (1σ) of 2.78 × 109 molecules per cm3 which translated into the detection limit of 740 parts-per-trillion by volume (pptv/10-12) at a pressure of 115 Torr for an integration time of ∼167 seconds. To demonstrate the efficacy of the present system in real-life applications, we finally measured the mixing ratios of NH3 present in ambient air and human exhaled breath with high sensitivity and molecular specificity.

Toxicology Study No. S.0024589d 15, Human Cell Line Activation Test of the Novel Energetic, 3,4 -Dinitropyrazole (DNP)

DTIC Science & Technology

2016-04-01

potential. The h-CLAT is one of many non- animal skin sensitizing tests , and it comprises part of an integrated testing strategy with two other in vitro...Protocol No. 158. 2015: European Union Reference Laboratory for Alternatives to Animal Testing [18, 19]. Toxicology Study No. S.0024589d-15, April...Alternatives to Animal Testing [18, 19]. If the EC200 or EC150 fell below the lowest dose, the values were extrapolated by the following equations

Results from a round robin test for the ecotoxicological evaluation of construction products using two leaching tests and an aquatic test battery.

PubMed

Gartiser, Stefan; Heisterkamp, Ines; Schoknecht, Ute; Burkhardt, Michael; Ratte, Monika; Ilvonen, Outi; Brauer, Frank; Brückmann, Jan; Dabrunz, André; Egeler, Philipp; Eisl, Andrea-Maria; Feiler, Ute; Fritz, Ines; König, Sabina; Lebertz, Herbert; Pandard, Pascal; Pötschke, Gabriele; Scheerbaum, Dirk; Schreiber, Frank; Soldán, Přemysl; Weiß, Roland; Weltens, Reinhilde

2017-05-01

A European round robin test according to ISO 5725-2 was conceptually prepared, realised, and evaluated. The aim was to determine the inter-laboratory variability of the overall process for the ecotoxicological characterization of construction products in eluates and bioassays. To this end, two construction products BAM-G1 (granulate) and HSR-2 (roof sealing sheet), both made of EPDM polymers (rubber), were selected. The granular construction product was eluted in a one stage batch test, the planar product in the Dynamic Surface Leaching test (DSLT). A total of 17 laboratories from 5 countries participated in the round robin test: Germany (12), Austria (2), Belgium (1), Czech Republic (1) and France (1). A test battery of four standardised ecotoxicity tests with algae, daphnia, luminescent bacteria and zebrafish eggs was used. As toxicity measures, EC50 and LID values were calculated. All tests, except the fish egg test, were basically able to demonstrate toxic effects and the level of toxicity. The reproducibility of test results depended on the test specimens and the test organisms. Generally, the variability of the EC50 or LID values increased with the overall level of toxicity. For the very toxic BAM-G1 eluate a relative high variability of CV = 73%-110% was observed for EC50 in all biotests, while for the less toxic HSR-2 eluate the reproducibility of EC50 varied with sensitivity: it was very good (CV = 9.3%) for the daphnia test with the lowest sensitivity, followed by the algae test (CV = 36.4%). The luminescent bacteria test, being the most sensitive bioassay for HSR-2 Eluate, showed the highest variability (CV = 74.8%). When considering the complex overall process the reproducibility of bioassays with eluates from construction products was acceptable. Copyright © 2017. Published by Elsevier Ltd.

Ultraviolet filters differentially impact the expression of key endocrine and stress genes in embryos and larvae of Chironomus riparius.

PubMed

Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis

2016-07-01

Several organic UV filters have hormonal activity in vertebrates, as demonstrated in fishes, rodents and human cells. Despite the accumulation of filter contaminants in aquatic systems, research on their effects on the endocrine systems of freshwaters invertebrates is scarce. In this work, the effects of five frequently used UV filters were investigated in embryos and larvae of Chironomus riparius, which is a reference organism in ecotoxicology. LC50 values for larvae as well as the percentage of eclosion of eggs were determined following exposures to: octyl-p-methoxycinnamate (OMC) also known as 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4MBC); 4-hydroxybenzophenone (4HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). To assess sublethal effects, expression levels of the genes coding for the ecdysone receptor (EcR) and heat shock protein HSP70 were investigated as biomarkers for endocrine and stress effects at the cellular level. Life-stage-dependent sensitivity was found. In embryos, all of the UV filters provoked a significant overexpression of EcR at 24h after exposure. OC, 4MBC and OD-PABA also triggered transcriptional activation of the hsp70 stress gene in embryos. In contrast, in larvae, only 4MBC and OMC/EHMC increased EcR and hsp70 mRNA levels and OD-PABA upregulated only the EcR gene. These results revealed that embryos are particularly sensitive to UV filters, which affect endocrine regulation during development. Most UV filters also triggered the cellular stress response, and thus exhibit proteotoxic effects. The differences observed between embryos and larvae and the higher sensitivity of embryos highlight the importance of considering different life stages when evaluating the environmental risks of pollutants, particularly when analyzing endocrine effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Limits to global and Australian temperature change this century based on expert judgment of climate sensitivity

NASA Astrophysics Data System (ADS)

Grose, Michael R.; Colman, Robert; Bhend, Jonas; Moise, Aurel F.

2017-05-01

The projected warming of surface air temperature at the global and regional scale by the end of the century is directly related to emissions and Earth's climate sensitivity. Projections are typically produced using an ensemble of climate models such as CMIP5, however the range of climate sensitivity in models doesn't cover the entire range considered plausible by expert judgment. Of particular interest from a risk-management perspective is the lower impact outcome associated with low climate sensitivity and the low-probability, high-impact outcomes associated with the top of the range. Here we scale climate model output to the limits of expert judgment of climate sensitivity to explore these limits. This scaling indicates an expanded range of projected change for each emissions pathway, including a much higher upper bound for both the globe and Australia. We find the possibility of exceeding a warming of 2 °C since pre-industrial is projected under high emissions for every model even scaled to the lowest estimate of sensitivity, and is possible under low emissions under most estimates of sensitivity. Although these are not quantitative projections, the results may be useful to inform thinking about the limits to change until the sensitivity can be more reliably constrained, or this expanded range of possibilities can be explored in a more formal way. When viewing climate projections, accounting for these low-probability but high-impact outcomes in a risk management approach can complement the focus on the likely range of projections. They can also highlight the scale of the potential reduction in range of projections, should tight constraints on climate sensitivity be established by future research.

Putative adaptive inter-slope divergence of transposon frequency in fruit flies (Drosophila melanogaster) at "Evolution Canyon", Mount Carmel, Israel.

PubMed

Beiles, Avigdor; Raz, Shmuel; Ben-Abu, Yuval; Nevo, Eviatar

2015-10-14

The current analysis of transposon elements (TE) in Drosophila melanogaster at Evolution Canyon, (EC), Israel, is based on data and analysis done by our collaborators (Drs. J. Gonzalez, J. Martinez and W. Makalowski, this issue). They estimated the frequencies of 28 TEs (transposon elements) in fruit flies (D. melanogaster) from the ecologically tropic, hot, and dry south-facing slope (SFS) or "African" slope (AS) of EC and compared it with the TE frequencies on the temperate-cool and humid north-facing slope (NFS) or "European" slope (ES), separated, on average, by 250 m. The flies were sampled from two stations on each slope. We received their results, including the frequencies of each TE on each slope, and the probabilities of the statistical analyses (G-tests) of each TE separately. We continued the analysis of the inter-slope differences of the frequencies of the TEs, and based our different conclusions on that analysis and on the difference between micro (=EC) and macro (2000 km.) comparisons [Gonzalez et al. 2015 doi: 10.1186/s13062-015-0075-4 ]. Our collaborators based all their conclusions on the non-significant results of each of the individual tests of the 28 TEs. We analysed also the distribution of the TE differences between the slopes, based on their results. Thirteen TEs were more frequent on the SFS, 11 were more frequent on the NFS, and four had equal frequencies. Because of the equalizing effect of the ongoing migration, only small and temporary differences between the slopes (0 - 0.06) were regarded by us as random fluctuations (drift). Three TEs were intermediate (0.08-0.09) and await additional research. The 11 TEs with large frequency differences (0.12 - 0.22) were regarded by us as putative adaptive TEs, because the equalizing power of ongoing migration will eliminate random large differences. Five of them were higher on the SFS and six were higher on the NFS. Gaps in the distribution of the differences distinguished between the large and small differences. The large gap among the 11 TEs favored on the NFS was significant and supports our rejection of drift as the only explanation of the distribution of the slope differences. The gaps in the distribution of the differences separated the putative TEs with strong enough selection from those TEs that couldn't overrule the migration. The results are compared and contrasted with the directional effect of the frequencies of the same TEs in the study of global climatic comparisons across thousands of kilometers. From the 11 putative adaptive TEs in the local "Evolution Canyon," six differentiate in the same direction as in the continental comparisons and four in the opposite direction. One TE, FBti0019144, differentiated in EC in the same direction as in Australia and in the opposite direction to that of North America. We presume that the major divergent evolutionary driving force at the local EC microsite is natural selection overruling gene flow. Therefore, after we rejected drift as an explanation of all the large slope differences, we regarded them as putatively adaptive. In order to substantiate the individual TE adaptation, we need to increase the sample sizes and reveal the significant adaptive TEs. The comparison of local and global studies show only partial similarity in the adaptation of the TEs, because of the dryness of the ecologically tropical climate in EC, in contrast to the wet tropical climate in the global compared climates. Moreover, adaptation of a TE may be expressed only in part of the time and specific localities.

Biochemical and toxicological effects of organic (herbicide Primextra(®) Gold TZ) and inorganic (copper) compounds on zooplankton and phytoplankton species.

PubMed

Filimonova, Valentina; Gonçalves, Fernando; Marques, João C; De Troch, Marleen; Gonçalves, Ana M M

2016-08-01

In Europe, mainly in the Mediterranean region, an intensive usage of pesticides was recorded during the past 30 years. According to information from agricultural cooperatives of the Mondego valley (Figueira da Foz, Portugal), Primextra(®) Gold TZ is the most used herbicide in corn crop fields and one of the 20 best-selling herbicides in Portugal. Copper is mainly used in pesticide formulations. This study aims to determine the ecotoxicological and biochemical (namely fatty acid profiles) effects of the herbicide Primextra(®) Gold TZ and the metal copper on marine plankton. The organisms used in this study are three planktonic species: the marine diatom Thalassiosira weissflogii, the estuarine copepod Acartia tonsa and nauplii of the marine brine shrimp Artemia franciscana. Fatty acids (FAs) are one of the most important molecules transferred across the plant-animal interface in aquatic food webs and can be used as good indicators of stress. The conducted lab incubations show that T. weissflogii is the most sensitive species to the herbicide followed by A. tonsa (EC50=0.0078mg/L and EC50=0.925mg/L, respectively), whereas the copepod was the most sensitive species to the metal followed by T. weissflogii (EC50=0.234mg/L and EC50=0.383mg/L, respectively). A. franciscana was the most tolerant organism both to the herbicide and to the metal (EC50=20.35mg/L and EC50=18.93mg/L, respectively). Changes in the FA profiles of primary producer and primary consumers were observed, with the increase of saturated FA and decrease of unsaturated FA contents, especially of highly unsaturated FAs that can be obtained mainly from food and therefore are referred to as 'essential FA'. The study suggests that discharges of Primextra(®) Gold TZ or other pesticides mainly composed by copper may be a threat to plankton populations causing changes in the FA contents and thus in their nutritive value, with severe repercussions for higher trophic levels and thus the entire food web. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantifying Key Climate Parameter Uncertainties Using an Earth System Model with a Dynamic 3D Ocean

NASA Astrophysics Data System (ADS)

Olson, R.; Sriver, R. L.; Goes, M. P.; Urban, N.; Matthews, D.; Haran, M.; Keller, K.

2011-12-01

Climate projections hinge critically on uncertain climate model parameters such as climate sensitivity, vertical ocean diffusivity and anthropogenic sulfate aerosol forcings. Climate sensitivity is defined as the equilibrium global mean temperature response to a doubling of atmospheric CO2 concentrations. Vertical ocean diffusivity parameterizes sub-grid scale ocean vertical mixing processes. These parameters are typically estimated using Intermediate Complexity Earth System Models (EMICs) that lack a full 3D representation of the oceans, thereby neglecting the effects of mixing on ocean dynamics and meridional overturning. We improve on these studies by employing an EMIC with a dynamic 3D ocean model to estimate these parameters. We carry out historical climate simulations with the University of Victoria Earth System Climate Model (UVic ESCM) varying parameters that affect climate sensitivity, vertical ocean mixing, and effects of anthropogenic sulfate aerosols. We use a Bayesian approach whereby the likelihood of each parameter combination depends on how well the model simulates surface air temperature and upper ocean heat content. We use a Gaussian process emulator to interpolate the model output to an arbitrary parameter setting. We use Markov Chain Monte Carlo method to estimate the posterior probability distribution function (pdf) of these parameters. We explore the sensitivity of the results to prior assumptions about the parameters. In addition, we estimate the relative skill of different observations to constrain the parameters. We quantify the uncertainty in parameter estimates stemming from climate variability, model and observational errors. We explore the sensitivity of key decision-relevant climate projections to these parameters. We find that climate sensitivity and vertical ocean diffusivity estimates are consistent with previously published results. The climate sensitivity pdf is strongly affected by the prior assumptions, and by the scaling parameter for the aerosols. The estimation method is computationally fast and can be used with more complex models where climate sensitivity is diagnosed rather than prescribed. The parameter estimates can be used to create probabilistic climate projections using the UVic ESCM model in future studies.

Climate sensitivity of DSSAT under different agriculture practice scenarios in China

NASA Astrophysics Data System (ADS)

Xia, L.; Robock, A.

2014-12-01

Crop yields are sensitive to both agricultural practice and climate changes. Under different agricultural practice scenarios, crop yield may have different climate sensitivities. Since it is important to understand how future climate changes affect agriculture productivity and what the potential adaptation strategies would be to compensate for possible negative impacts on crop production, we performed experiments to study climate sensitivity under different agricultural practice scenarios for rice, maize and wheat in the top four production provinces in China using the Decision Support System for Agrotechnology Transfer (DSSAT) crop model. The agricultural practice scenarios include four categories: different amounts of nitrogen fertilizer or no nitrogen stress; irrigation turned on or off, or no water stress; all possible seeds in the DSSAT cultivar data base; and different planting dates. For the climate sensitivity test, the control climate is from 1998 to 2007, and we individually modify four climate variables: daily maximum and minimum temperature by +2 °C and -2 °C, daily precipitation by +20% and -20%, and daily solar radiation by + 20% and -20%. With more nitrogen fertilizer applied, crops are more sensitive to temperature changes as well as precipitation changes because of their release from nitrogen limitation. With irrigation turned on, crop yield sensitivity to temperature decreases in most of the regions depending on the amount of the local precipitation, since more water is available and soil temperature varies less with higher soil moisture. Those results indicate that there could be possible agriculture adaptation strategies under certain future climate scenarios. For example, increasing nitrogen fertilizer usage by a certain amount might compensate for the negative impact on crop yield from climate changes. However, since crops are more sensitive to climate changes when there is more nitrogen fertilizer applied, if the climate changes are unfavorable to crop yields, increasing nitrogen fertilizer usage at certain levels might enhance the negative climate change impact. Enhanced nitrogen fertilizer use might have additional negative impacts on climate because of nitrogen emissions to the atmosphere, but those effects were not studied here.

Carbonaceous aerosols in the air masses transported from Indochina to Taiwan: Long-term observation at Mt. Lulin

NASA Astrophysics Data System (ADS)

Chuang, Ming-Tung; Lee, Chung-Te; Chou, Charles C.-K.; Lin, Neng-Huei; Sheu, Guey-Rong; Wang, Jia-Lin; Chang, Shuenn-Chin; Wang, Sheng-Hsiang; Chi, Kai Hsien; Young, Chea-Yuan; Huang, Hill; Chen, Horng-Wen; Weng, Guo-Hau; Lai, Sin-Yu; Hsu, Shao-Peng; Chang, Yu-Jia; Chang, Jia-Hon; Wu, Xyue-Chang

2014-06-01

Eight carbonaceous fractions from aerosols were resolved using the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol (Chow et al., 1993). The aerosols were collected at the Mountain Lulin Atmospheric Background Station (Mt. Lulin, 2862 m a.s.l.) in Central Taiwan from April 2003 to April 2012. The monthly and yearly levels of organic carbon (OC) and elemental carbon (EC) varied consistently with PM2.5 mass concentrations during biomass burning (BB) period. The highest monthly carbonaceous content was observed in March and the highest yearly carbonaceous concentration was observed in 2007. This finding is consistent with the BB activity in Indochina and indicates that carbonaceous content is a major component of BB aerosols. Lee et al. (2011) classified four trajectory groups from the air masses transported to Mt. Lulin during the aerosol collection period. For the air masses transported from the BB area (the BB group) in Indochina, the carbonaceous content was greater than the water-soluble ions in PM2.5, and the OC/EC ratio (4.8 ± 1.5) was high. With EC as the indicator of primary emission sources, the air masses of the BB group were found to contain more primary than secondary OC. The Anthropogenic group (from the local and free troposphere below the 700-hPa pressure level over the Asian continent) probably contained more secondary than primary OC or the sources of OC and EC could be quite diverse. The average char-EC/soot-EC (low-temperature EC/high-temperature EC) ratios were 3.9 ± 3.5, 0.4 ± 0.4, 0.9 ± 0.8, and 0.3 ± 0.4 for the trajectory groups BB, SNBB (from BB source areas during the non-BB period), Anthropogenic, and FT (from the oceanic area and the free troposphere above the 700-hPa pressure level over the Asian continent), respectively. The presence of a high char-EC/soot-EC ratio confirmed the correct classification of the BB group, whereas the low ratios from the other groups indicated the strong influence of vehicle exhaust. It is noted that higher OC and EC levels were obtained at Mt. Lulin as compared with those obtained at other high-elevation sites. This difference suggested that the Indochina BB plume exhibited a more serious climatic impact on the background air in East Asia than in other places in Asia and Europe. On the basis of the carbonaceous levels of the SNBB and FT groups, the background OC and EC levels of approximately 3000 m in the West Pacific are around 1.33 μg m-3 and 0.35 μg m-3, respectively.

Sensitivity of Regulated Flow Regimes to Climate Change in the Western United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Tian; Voisin, Nathalie; Leng, Guoyong

Water management activities or flow regulations modify water fluxes at the land surface and affect water resources in space and time. We hypothesize that flow regulations change the sensitivity of river flow to climate change with respect to unmanaged water resources. Quantifying these changes in sensitivity could help elucidate the impacts of water management at different spatiotemporal scales and inform climate adaptation decisions. In this study, we compared the emergence of significant changes in natural and regulated river flow regimes across the Western United States from simulations driven by multiple climate models and scenarios. We find that significant climate change-inducedmore » alterations in natural flow do not cascade linearly through water management activities. At the annual time scale, 50% of the Hydrologic Unit Code 4 (HUC4) sub-basins over the Western U.S. regions tend to have regulated flow regime more sensitive to the climate change than natural flow regime. Seasonality analyses show that the sensitivity varies remarkably across the seasons. We also find that the sensitivity is related to the level of water management. For 35% of the HUC4 sub-basins with the highest level of water management, the summer and winter flows tend to show a heightened sensitivity to climate change due to the complexity of joint reservoir operations. We further demonstrate that the impacts of considering water management in models are comparable to those that arises from uncertainties across climate models and emission scenarios. This prompts further climate adaptation studies research about nonlinearity effects of climate change through water management activities.« less

Comparative analyses of fungicide sensitivity and SSR marker variations indicate a low risk of developing azoxystrobin resistance in Phytophthora infestans

PubMed Central

Qin, Chun-Fang; He, Meng-Han; Chen, Feng-Ping; Zhu, Wen; Yang, Li-Na; Wu, E-Jiao; Guo, Zheng-Liang; Shang, Li-Ping; Zhan, Jiasui

2016-01-01

Knowledge of the evolution of fungicide resistance is important in securing sustainable disease management in agricultural systems. In this study, we analyzed and compared the spatial distribution of genetic variation in azoxystrobin sensitivity and SSR markers in 140 Phytophthora infestans isolates sampled from seven geographic locations in China. Sensitivity to azoxystrobin and its genetic variation in the pathogen populations was measured by the relative growth rate (RGR) at four fungicide concentrations and determination of the effective concentration for 50% inhibition (EC50). We found that all isolates in the current study were sensitive to azoxystrobin and their EC50 was similar to that detected from a European population about 20 years ago, suggesting the risk of developing azoxystrobin resistance in P. infestans populations is low. Further analyses indicate that reduced genetic variation and high fitness cost in resistant mutations are the likely causes for the low evolutionary likelihood of developing azoxystrobin resistance in the pathogen. We also found a negative correlation between azoxystrobin tolerance in P. infestans populations and the mean annual temperature of collection sites, suggesting that global warming may increase the efficiency of using the fungicide to control the late blight. PMID:26853908

Comparative analyses of fungicide sensitivity and SSR marker variations indicate a low risk of developing azoxystrobin resistance in Phytophthora infestans.

PubMed

Qin, Chun-Fang; He, Meng-Han; Chen, Feng-Ping; Zhu, Wen; Yang, Li-Na; Wu, E-Jiao; Guo, Zheng-Liang; Shang, Li-Ping; Zhan, Jiasui

2016-02-08

Knowledge of the evolution of fungicide resistance is important in securing sustainable disease management in agricultural systems. In this study, we analyzed and compared the spatial distribution of genetic variation in azoxystrobin sensitivity and SSR markers in 140 Phytophthora infestans isolates sampled from seven geographic locations in China. Sensitivity to azoxystrobin and its genetic variation in the pathogen populations was measured by the relative growth rate (RGR) at four fungicide concentrations and determination of the effective concentration for 50% inhibition (EC50). We found that all isolates in the current study were sensitive to azoxystrobin and their EC50 was similar to that detected from a European population about 20 years ago, suggesting the risk of developing azoxystrobin resistance in P. infestans populations is low. Further analyses indicate that reduced genetic variation and high fitness cost in resistant mutations are the likely causes for the low evolutionary likelihood of developing azoxystrobin resistance in the pathogen. We also found a negative correlation between azoxystrobin tolerance in P. infestans populations and the mean annual temperature of collection sites, suggesting that global warming may increase the efficiency of using the fungicide to control the late blight.

Randomized controlled trial of the cognitive side-effects of magnetic seizure therapy (MST) and electroconvulsive shock (ECS).

PubMed

Moscrip, Tammy D; Terrace, Herbert S; Sackeim, Harold A; Lisanby, Sarah H

2006-02-01

Magnetic seizure therapy (MST) is under development as a means of improving the cognitive side-effect profile of electroconvulsive therapy (ECT) by inducing more spatially delimited seizures that spare cortical regions involved in memory. We tested whether MST had a cognitive side-effect profile distinct from electroconvulsive shock (ECS) in a non-human primate model, using the Columbia University Primate Cognitive Profile, which has been shown to be sensitive to the cognitive effects of ECS. Using a within-subject cross-over design, daily ECS, MST, and sham (anaesthesia-only) interventions were administered in 5-wk blocks. Rhesus macaques (n = 2) were trained on a long-term memory task, an anterograde learning and memory task, and a combined anterograde and retrograde task where learning and memory were evaluated for new and previously learned 3-item lists. Acutely following each intervention, monkeys were tested on the cognitive battery twice daily, separated by a 3-h retention interval. Overall, monkeys were least accurate following ECS (p's < 0.05) compared to sham and MST. This effect was most marked for long-term memory of a constant target, short-term memory of a variable target and recall of previously learned 3-item lists. Monkeys were slowest to complete all tasks following ECS (p's = 0.0001). Time to task completion following MST did not differ from sham. These findings suggest that MST results in a more benign acute cognitive side-effect profile than ECS in this model, consistent with initial observations with human MST.

CD30 antigen in embryonal carcinoma and embryogenesis and release of the soluble molecule.

PubMed Central

Latza, U.; Foss, H. D.; Dürkop, H.; Eitelbach, F.; Dieckmann, K. P.; Loy, V.; Unger, M.; Pizzolo, G.; Stein, H.

1995-01-01

The expression, serological detection, and possible functional role of the CD30 antigen in Hodgkin's disease and anaplastic large cell lymphoma is well documented. In embryonal carcinoma (EC), the expression of this cytokine receptor has been demonstrated only by immunohistology. Because the CD30 monoclonal antibody Ki-1 was found to cross-react with an unrelated molecule, we examined by in situ hybridization testicular germ cell neoplasms for the presence of CD30-specific transcripts. CD30 mRNA was detectable in the tumor cells of 9 of 9 cases of EC or mixed germ cell tumors with an EC component but in no other nonlymphoid tumors. Thus, the CD30 transcript expression pattern proved to be identical to the immunostaining pattern seen with the CD30-specific monoclonal antibody Ber-H2. By Northern blot analysis, CD30 transcripts could be demonstrated in the EC cell line Tera-2. Employing a highly sensitive second generation sandwich enzyme-linked immunosorbent assay, we could detect the soluble CD30 molecule in 8 of 8 sera from patients with a diagnosis of EC but not in 8 of 10 sera from patients with other testicular germ cell tumors. In fetal tissue, no CD30-expressing germ cells or epithelial cells could be observed. Thus, the cellularly expressed CD30 marker for testicular neoplasms of EC type. Moreover, the serum levels of soluble CD30 antigen seem to be a promising parameter for monitoring patients with EC. Images Figure 1 Figure 2 PMID:7856755

Incidence of macroscopically occult neoplasias in Barrett's esophagus: are random biopsies dispensable in the era of advanced endoscopic imaging?

PubMed

Pohl, Juergen; Pech, Oliver; May, Andrea; Manner, Hendrik; Fissler-Eckhoff, Annette; Ell, Christian

2010-11-01

The gold standard for endoscopic surveillance of Barrett's esophagus (BE) includes targeted biopsies (TBs) from abnormalities as well as stepwise four-quadrant biopsies (4QBs) for detection of invisible high-grade intraepithelial neoplasias (HGINs) or early carcinomas (ECs). In a large mixed BE population, we investigated the rate of HGINs/ECs that are macroscopically occult to enhanced visualization with high-resolution endoscopy plus acetic acid chromoendoscopy. From January 2007 to December 2009, 701 consecutive BE patients were enrolled in a prospective study at a tertiary referral center. Of these, 406 patients had a history of HGIN/EC (high-risk group) and 295 patients did not (low-risk group). In 701 patients, 459 TBs and 5,485 4QBs were obtained. Altogether, 92 patients with 132 lesions containing HGINs/ECs were detected. For the diagnosis of HGINs/ECs, patient-related sensitivity and specificity rates of endoscopic imaging with TBs were 96.7 and 66.5%, with a positive and negative predictive value of 30.4 and 99.3%, respectively. In the high-risk group, 4QBs identified three additional patients (3.3%) with macroscopically occult HGINs/ECs. In the low-risk group, no HGINs/ECs were identified with either biopsy approach. Advanced endoscopic imaging identifies the vast majority of BE patients with early neoplasias, and the additive effect of 4QB is minimal. Therefore, in low- and high-risk patients, limiting endoscopic surveillance to guided biopsies is justified in specialized high-volume centers with permanent quality control. However, we do not advocate abandoning 4QB outside this setting.

Nuclear envelope proteins Nesprin2 and LaminA regulate proliferation and apoptosis of vascular endothelial cells in response to shear stress.

PubMed

Han, Yue; Wang, Lu; Yao, Qing-Ping; Zhang, Ping; Liu, Bo; Wang, Guo-Liang; Shen, Bao-Rong; Cheng, Binbin; Wang, Yingxiao; Jiang, Zong-Lai; Qi, Ying-Xin

2015-05-01

The dysfunction of vascular endothelial cells (ECs) influenced by flow shear stress is crucial for vascular remodeling. However, the roles of nuclear envelope (NE) proteins in shear stress-induced EC dysfunction are still unknown. Our results indicated that, compared with normal shear stress (NSS), low shear stress (LowSS) suppressed the expression of two types of NE proteins, Nesprin2 and LaminA, and increased the proliferation and apoptosis of ECs. Targeted small interfering RNA (siRNA) and gene overexpression plasmid transfection revealed that Nesprin2 and LaminA participate in the regulation of EC proliferation and apoptosis. A protein/DNA array was further used to detect the activation of transcription factors in ECs following transfection with target siRNAs and overexpression plasmids. The regulation of AP-2 and TFIID mediated by Nesprin2 and the activation of Stat-1, Stat-3, Stat-5 and Stat-6 by LaminA were verified under shear stress. Furthermore, using Ingenuity Pathway Analysis software and real-time RT-PCR, the effects of Nesprin2 or LaminA on the downstream target genes of AP-2, TFIID, and Stat-1, Stat-3, Stat-5 and Stat-6, respectively, were investigated under LowSS. Our study has revealed that NE proteins are novel mechano-sensitive molecules in ECs. LowSS suppresses the expression of Nesprin2 and LaminA, which may subsequently modulate the activation of important transcription factors and eventually lead to EC dysfunction. Copyright © 2015 Elsevier B.V. All rights reserved.

An active learning approach for rapid characterization of endothelial cells in human tumors.

PubMed

Padmanabhan, Raghav K; Somasundar, Vinay H; Griffith, Sandra D; Zhu, Jianliang; Samoyedny, Drew; Tan, Kay See; Hu, Jiahao; Liao, Xuejun; Carin, Lawrence; Yoon, Sam S; Flaherty, Keith T; Dipaola, Robert S; Heitjan, Daniel F; Lal, Priti; Feldman, Michael D; Roysam, Badrinath; Lee, William M F

2014-01-01

Currently, no available pathological or molecular measures of tumor angiogenesis predict response to antiangiogenic therapies used in clinical practice. Recognizing that tumor endothelial cells (EC) and EC activation and survival signaling are the direct targets of these therapies, we sought to develop an automated platform for quantifying activity of critical signaling pathways and other biological events in EC of patient tumors by histopathology. Computer image analysis of EC in highly heterogeneous human tumors by a statistical classifier trained using examples selected by human experts performed poorly due to subjectivity and selection bias. We hypothesized that the analysis can be optimized by a more active process to aid experts in identifying informative training examples. To test this hypothesis, we incorporated a novel active learning (AL) algorithm into FARSIGHT image analysis software that aids the expert by seeking out informative examples for the operator to label. The resulting FARSIGHT-AL system identified EC with specificity and sensitivity consistently greater than 0.9 and outperformed traditional supervised classification algorithms. The system modeled individual operator preferences and generated reproducible results. Using the results of EC classification, we also quantified proliferation (Ki67) and activity in important signal transduction pathways (MAP kinase, STAT3) in immunostained human clear cell renal cell carcinoma and other tumors. FARSIGHT-AL enables characterization of EC in conventionally preserved human tumors in a more automated process suitable for testing and validating in clinical trials. The results of our study support a unique opportunity for quantifying angiogenesis in a manner that can now be tested for its ability to identify novel predictive and response biomarkers.

CTP synthase 1, a smooth muscle-sensitive therapeutic target for effective vascular repair

PubMed Central

Tang, Rui; Cui, Xiao-Bing; Wang, Jia-Ning; Chen, Shi-You

2013-01-01

Objective Vascular remodeling due to smooth muscle cell (SMC) proliferation and neointima formation is a major medical challenge in cardiovascular intervention. However, anti-neointima drugs often indistinguishably block re-endothelialization, an essential step toward successful vascular repair, due to their non-specific effect on endothelial cells (EC). The objective of this study was to identify a therapeutic target that differentially regulates SMC and EC proliferation. Approach and Results By using both rat balloon-injury and mouse wire-injury models, we identified CTP synthase (CTPS) as one of the potential targets that may be used for developing therapeutics for treating neointima-related disorders. CTPS1 was induced in proliferative SMCs in vitro and neointima SMCs in vivo. Blockade of CTPS1 expression by small hairpin RNA or activity by cyclopentenyl cytosine suppressed SMC proliferation and neointima formation. Surprisingly, cyclopentenyl cytosine had much less effect on EC proliferation. Of importance, blockade of CTPS1 in vivo sustained the re-endothelialization due to induction of CTP synthesis salvage pathway enzymes nucleoside diphosphate kinase A and B in ECs. Diphosphate kinase B appeared to preserve EC proliferation via utilization of extracellular cytidine to synthesize CTP. Indeed, blockade of both CTPS1 and diphosphate kinase B suppressed EC proliferation in vitro and the re-endothelization in vivo. Conclusions Our study uncovered a fundamental difference in CTP biosynthesis between SMCs and ECs during vascular remodeling, which provided a novel strategy by using cyclopentenyl cytosine or other CTPS1 inhibitors to selectively block SMC proliferation without disturbing or even promoting re-endothelialization for effective vascular repair following injury. PMID:24008161

Decadal Variations in Eastern Canada's Taiga Wood Biomass Production Forced by Ocean-Atmosphere Interactions.

PubMed

Boucher, Etienne; Nicault, Antoine; Arseneault, Dominique; Bégin, Yves; Karami, Mehdi Pasha

2017-05-26

Across Eastern Canada (EC), taiga forests represent an important carbon reservoir, but the extent to which climate variability affects this ecosystem over decades remains uncertain. Here, we analyze an extensive network of black spruce (Picea mariana Mill.) ring width and wood density measurements and provide new evidence that wood biomass production is influenced by large-scale, internal ocean-atmosphere processes. We show that while black spruce wood biomass production is primarily governed by growing season temperatures, the Atlantic ocean conveys heat from the subtropics and influences the decadal persistence in taiga forests productivity. Indeed, we argue that 20-30 years periodicities in Sea Surface Temperatures (SSTs) as part of the the Atlantic Multi-decadal Oscillation (AMO) directly influence heat transfers to adjacent lands. Winter atmospheric conditions associated with the North Atlantic Oscillation (NAO) might also impact EC's taiga forests, albeit indirectly, through its effect on SSTs and sea ice conditions in surrounding seas. Our work emphasizes that taiga forests would benefit from the combined effects of a warmer atmosphere and stronger ocean-to-land heat transfers, whereas a weakening of these transfers could cancel out, for decades or longer, the positive effects of climate change on Eastern Canada's largest ecosystem.

Thermal/Optical Methods for Elemental Carbon Quantification in Soils and Urban Dusts: Equivalence of Different Analysis Protocols

PubMed Central

Han, Yongming; Chen, Antony; Cao, Junji; Fung, Kochy; Ho, Fai; Yan, Beizhan; Zhan, Changlin; Liu, Suixin; Wei, Chong; An, Zhisheng

2013-01-01

Quantifying elemental carbon (EC) content in geological samples is challenging due to interferences of crustal, salt, and organic material. Thermal/optical analysis, combined with acid pretreatment, represents a feasible approach. However, the consistency of various thermal/optical analysis protocols for this type of samples has never been examined. In this study, urban street dust and soil samples from Baoji, China were pretreated with acids and analyzed with four thermal/optical protocols to investigate how analytical conditions and optical correction affect EC measurement. The EC values measured with reflectance correction (ECR) were found always higher and less sensitive to temperature program than the EC values measured with transmittance correction (ECT). A high-temperature method with extended heating times (STN120) showed the highest ECT/ECR ratio (0.86) while a low-temperature protocol (IMPROVE-550), with heating time adjusted for sample loading, showed the lowest (0.53). STN ECT was higher than IMPROVE ECT, in contrast to results from aerosol samples. A higher peak inert-mode temperature and extended heating times can elevate ECT/ECR ratios for pretreated geological samples by promoting pyrolyzed organic carbon (PyOC) removal over EC under trace levels of oxygen. Considering that PyOC within filter increases ECR while decreases ECT from the actual EC levels, simultaneous ECR and ECT measurements would constrain the range of EC loading and provide information on method performance. Further testing with standard reference materials of common environmental matrices supports the findings. Char and soot fractions of EC can be further separated using the IMPROVE protocol. The char/soot ratio was lower in street dusts (2.2 on average) than in soils (5.2 on average), most likely reflecting motor vehicle emissions. The soot concentrations agreed with EC from CTO-375, a pure thermal method. PMID:24358286

Distinct Spatiotemporal Activation Patterns of the Perirhinal-Entorhinal Network in Response to Cortical and Amygdala Input

PubMed Central

Willems, Janske G. P.; Wadman, Wytse J.; Cappaert, Natalie L. M.

2016-01-01

The perirhinal (PER) and entorhinal cortex (EC) receive input from the agranular insular cortex (AiP) and the subcortical lateral amygdala (LA) and the main output area is the hippocampus. Information transfer through the PER/EC network however, is not always guaranteed. It is hypothesized that this network actively regulates the (sub)cortical activity transfer to the hippocampal network and that the inhibitory system is involved in this function. This study determined the recruitment by the AiP and LA afferents in PER/EC network with the use of voltage sensitive dye (VSD) imaging in horizontal mouse brain slices. Electrical stimulation (500 μA) of the AiP induced activity that gradually propagated predominantly in the rostro-caudal direction: from the PER to the lateral EC (LEC). In the presence of 1 μM of the competitive γ-aminobutyric acid (GABAA) receptor antagonist bicuculline, AiP stimulation recruited the medial EC (MEC) as well. In contrast, LA stimulation (500 μA) only induced activity in the deep layers of the PER. In the presence of bicuculline, the initial population activity in the PER propagated further towards the superficial layers and the EC after a delay. The latency of evoked responses decreased with increasing stimulus intensities (50–500 μA) for both the AiP and LA stimuli. The stimulation threshold for evoking responses in the PER/EC network was higher for the LA than for the AiP. This study showed that the extent of the PER/EC network activation depends on release of inhibition. When GABAA dependent inhibition is reduced, both the AiP and the LA activate spatially overlapping regions, although in a distinct spatiotemporal fashion. It is therefore hypothesized that the inhibitory network regulates excitatory activity from both cortical and subcortical areas that has to be transmitted through the PER/EC network. PMID:27378860

Eddy covariance carbonyl sulfide flux measurements with a quantum cascade laser absorption spectrometer

NASA Astrophysics Data System (ADS)

Gerdel, Katharina; Spielmann, Felix M.; Hammerle, Albin; Wohlfahrt, Georg

2016-04-01

Carbonyl sulfide (COS) is the most abundant sulfur containing trace gas present in the troposphere at concentrations of around 500 ppt. Recent interest in COS by the ecosystem-physiological community has been sparked by the fact that COS co-diffuses into plant leaves pretty much the same way as carbon dioxide (CO2) does, but in contrast to CO2, COS is not known to be emitted by plants. Thus uptake of COS by vegetation has the potential to be used as a tracer for canopy gross photosynthesis, which cannot be measured directly, however represents a key term in the global carbon cycle. Since a few years, quantum cascade laser absorption spectrometers (QCLAS) are commercially available with the precision, sensitivity and time response suitable for eddy covariance (EC) flux measurements. While there exist a handful of published reports on EC flux measurements in the recent literature, no rigorous investigation of the applicability of QCLAS for EC COS flux measurements has been carried out so far, nor have been EC processing and QA/QC steps developed for carbon dioxide and water vapor flux measurements within FLUXNET been assessed for COS. The aim of this study is to close this knowledge gap, to discuss critical steps in the post-processing chain of COS EC flux measurements and to devise best-practice guidelines for COS EC flux data processing. To this end we collected EC COS (and CO2, H2O and CO) flux measurements above a temperate mountain grassland in Austria over the vegetation period 2015 with a commercially available QCLAS. We discuss various aspects of EC data post-processing, in particular issues with the time-lag estimation between sonic anemometer and QCLAS signals and QCLAS time series detrending, as well as QA/QC, in particular flux detection limits, random flux uncertainty, the interaction of various processing steps with common EC QA/QC filters (e.g. detrending and stationarity tests), u*-filtering, etc.

Eddy covariance N2O flux measurements at low flux rates: results from the InGOS campaign in a Danish willow field.

NASA Astrophysics Data System (ADS)

Ibrom, Andreas; Brümmer, Christian; Hensen, Arjan; van Asperen, Hella; Carter, Mette S.; Gasche, Rainer; Famulari, Daniela; Kutsch, Werner; Pilegaard, Kim; Ambus, Per

2014-05-01

Nitrous oxide (N2O) fluxes from soils are characterised by their high spatial and temporal variability. The fluxes depend on the availability of the substrates for nitrification and denitrification and soil physical and chemical conditions that control the metabolic microbial activity. The sporadic nature of the fluxes and their high sensitivity to alterations of the soil climate put very high demands on measurement approaches. Laser spectroscopy enables accurate and fast response detection of atmospheric N2O concentrations and is used for eddy covariance (EC) flux measurements. Alternatively N2O fluxes can be measured with chambers together with high precision analysers. Differences in the measurement approaches and system designs are expected to have a considerable influence on the accuracy of the flux estimation. This study investigates how three different eddy covariance systems perform in a situation of low N2O fluxes from a flat surface. Chamber flux measurements with differing chamber and analyser designs are used for comparison. In April 2013, the EU research infrastructure project InGOS (http://www.ingos-infrastructure.eu/) organised a campaign of N2O flux measurements in a willow plantation close to the Risø Campus of the Technical University of Denmark. The willow field was harvested in February 2013 and received mineral fertiliser equivalent to 120 kg N ha-1 before the campaign started. Three different eddy covariance systems took part in the campaign: two Aerodyne quantum cascade laser (QCL) based systems and one Los Gatos Research off-axis integrated-cavity-output spectroscopy (ICOS) system for N2O and CO. The sonic anemometers were all installed at 2 m height above the bare ground. Gill R3 type sonic anemometers were used with QCL systems and a Gil HS-50 with the ICOS system. The 10 Hz raw data were analysed with group specific softwares and procedures. The local conditions in the exceptionally cold and dry spring 2013 did not lead to large N2O flux rates. All three EC systems showed 30 min. flux values varying around zero nmol m-2 s-1. This noise was considerably lower in the EC systems that used QCL analysers. The maximum daily averages of the uncorrected fluxes from two of the EC systems reached 0.26 (ICOS/HS50) and 0.28 (QCL/R3) nmol m-2 s-1.Spectral correction increased the flux estimates up to, e.g., 180% equivalent to 0.54 nmol m-2 s-1. The flux estimates from the soil chambers were with one exception higher than the flux estimates obtained from the EC systems with highest daily averages ranging from 0.1 up to 2 nmol m-2 s-1. These large differences were unexpected, because at least two of the EC systems were shown to accurately measure fluxes at such higher levels at another InGOS campaign in a fertilised Scottish grazed meadow. We use spectral analysis to examine the raw data for the effects of sensor noise on the flux estimates and discuss strategies on how to correct or account for it. Furthermore possible causes for the observed differences between the observed EC and chamber flux estimates will be discussed.

The Dependencies of Ecosystem Pattern, Structure, and Dynamics on Climate, Climate Variability, and Climate Change

NASA Astrophysics Data System (ADS)

Flanagan, S.; Hurtt, G. C.; Fisk, J. P.; Rourke, O.

2012-12-01

A robust understanding of the sensitivity of the pattern, structure, and dynamics of ecosystems to climate, climate variability, and climate change is needed to predict ecosystem responses to current and projected climate change. We present results of a study designed to first quantify the sensitivity of ecosystems to climate through the use of climate and ecosystem data, and then use the results to test the sensitivity of the climate data in a state-of the art ecosystem model. A database of available ecosystem characteristics such as mean canopy height, above ground biomass, and basal area was constructed from sources like the National Biomass and Carbon Dataset (NBCD). The ecosystem characteristics were then paired by latitude and longitude with the corresponding climate characteristics temperature, precipitation, photosynthetically active radiation (PAR) and dew point that were retrieved from the North American Regional Reanalysis (NARR). The average yearly and seasonal means of the climate data, and their associated maximum and minimum values, over the 1979-2010 time frame provided by NARR were constructed and paired with the ecosystem data. The compiled results provide natural patterns of vegetation structure and distribution with regard to climate data. An advanced ecosystem model, the Ecosystem Demography model (ED), was then modified to allow yearly alterations to its mechanistic climate lookup table and used to predict the sensitivities of ecosystem pattern, structure, and dynamics to climate data. The combined ecosystem structure and climate data results were compared to ED's output to check the validity of the model. After verification, climate change scenarios such as those used in the last IPCC were run and future forest structure changes due to climate sensitivities were identified. The results of this study can be used to both quantify and test key relationships for next generation models. The sensitivity of ecosystem characteristics to climate data shown in the database construction and by the model reinforces the need for high-resolution datasets and stresses the importance of understanding and incorporating climate change scenarios into earth system models.

Automated general temperature correction method for dielectric soil moisture sensors

NASA Astrophysics Data System (ADS)

Kapilaratne, R. G. C. Jeewantinie; Lu, Minjiao

2017-08-01

An effective temperature correction method for dielectric sensors is important to ensure the accuracy of soil water content (SWC) measurements of local to regional-scale soil moisture monitoring networks. These networks are extensively using highly temperature sensitive dielectric sensors due to their low cost, ease of use and less power consumption. Yet there is no general temperature correction method for dielectric sensors, instead sensor or site dependent correction algorithms are employed. Such methods become ineffective at soil moisture monitoring networks with different sensor setups and those that cover diverse climatic conditions and soil types. This study attempted to develop a general temperature correction method for dielectric sensors which can be commonly used regardless of the differences in sensor type, climatic conditions and soil type without rainfall data. In this work an automated general temperature correction method was developed by adopting previously developed temperature correction algorithms using time domain reflectometry (TDR) measurements to ThetaProbe ML2X, Stevens Hydra probe II and Decagon Devices EC-TM sensor measurements. The rainy day effects removal procedure from SWC data was automated by incorporating a statistical inference technique with temperature correction algorithms. The temperature correction method was evaluated using 34 stations from the International Soil Moisture Monitoring Network and another nine stations from a local soil moisture monitoring network in Mongolia. Soil moisture monitoring networks used in this study cover four major climates and six major soil types. Results indicated that the automated temperature correction algorithms developed in this study can eliminate temperature effects from dielectric sensor measurements successfully even without on-site rainfall data. Furthermore, it has been found that actual daily average of SWC has been changed due to temperature effects of dielectric sensors with a significant error factor comparable to ±1% manufacturer's accuracy.

Flow pathways and nutrient transport mechanisms drive hydrochemical sensitivity to climate change across catchments with different geology and topography

NASA Astrophysics Data System (ADS)

Crossman, J.; Futter, M. N.; Whitehead, P. G.; Stainsby, E.; Baulch, H. M.; Jin, L.; Oni, S. K.; Wilby, R. L.; Dillon, P. J.

2014-07-01

Hydrological processes determine the transport of nutrients and passage of diffuse pollution. Consequently, catchments are likely to exhibit individual hydrochemical responses (sensitivities) to climate change, which is expected to alter the timing and amount of runoff, and to impact in-stream water quality. In developing robust catchment management strategies and quantifying plausible future hydrochemical conditions it is therefore equally important to consider the potential for spatial variability in, and causal factors of, catchment sensitivity, as to explore future changes in climatic pressures. This study seeks to identify those factors which influence hydrochemical sensitivity to climate change. A perturbed physics ensemble (PPE), derived from a series of Global Climate Model (GCM) variants with specific climate sensitivities was used to project future climate change and uncertainty. Using the Integrated Catchment Model of Phosphorus Dynamics (INCA-P), we quantified potential hydrochemical responses in four neighbouring catchments (with similar land use but varying topographic and geological characteristics) in southern Ontario, Canada. Responses were assessed by comparing a 30 year baseline (1968-1997) to two future periods: 2020-2049 and 2060-2089. Although projected climate change and uncertainties were similar across these catchments, hydrochemical responses (sensitivity) were highly varied. Sensitivity was governed by soil type (influencing flow pathways) and nutrient transport mechanisms. Clay-rich catchments were most sensitive, with total phosphorus (TP) being rapidly transported to rivers via overland flow. In these catchments large annual reductions in TP loads were projected. Sensitivity in the other two catchments, dominated by sandy-loams, was lower due to a larger proportion of soil matrix flow, longer soil water residence times and seasonal variability in soil-P saturation. Here smaller changes in TP loads, predominantly increases, were projected. These results suggest that the clay content of soils could be a good indicator of the sensitivity of catchments to climatic input, and reinforces calls for catchment-specific management plans.

Flow pathways and nutrient transport mechanisms drive hydrochemical sensitivity to climate change across catchments with different geology and topography

NASA Astrophysics Data System (ADS)

Crossman, J.; Futter, M. N.; Whitehead, P. G.; Stainsby, E.; Baulch, H. M.; Jin, L.; Oni, S. K.; Wilby, R. L.; Dillon, P. J.

2014-12-01

Hydrological processes determine the transport of nutrients and passage of diffuse pollution. Consequently, catchments are likely to exhibit individual hydrochemical responses (sensitivities) to climate change, which are expected to alter the timing and amount of runoff, and to impact in-stream water quality. In developing robust catchment management strategies and quantifying plausible future hydrochemical conditions it is therefore equally important to consider the potential for spatial variability in, and causal factors of, catchment sensitivity, as it is to explore future changes in climatic pressures. This study seeks to identify those factors which influence hydrochemical sensitivity to climate change. A perturbed physics ensemble (PPE), derived from a series of global climate model (GCM) variants with specific climate sensitivities was used to project future climate change and uncertainty. Using the INtegrated CAtchment model of Phosphorus dynamics (INCA-P), we quantified potential hydrochemical responses in four neighbouring catchments (with similar land use but varying topographic and geological characteristics) in southern Ontario, Canada. Responses were assessed by comparing a 30 year baseline (1968-1997) to two future periods: 2020-2049 and 2060-2089. Although projected climate change and uncertainties were similar across these catchments, hydrochemical responses (sensitivities) were highly varied. Sensitivity was governed by quaternary geology (influencing flow pathways) and nutrient transport mechanisms. Clay-rich catchments were most sensitive, with total phosphorus (TP) being rapidly transported to rivers via overland flow. In these catchments large annual reductions in TP loads were projected. Sensitivity in the other two catchments, dominated by sandy loams, was lower due to a larger proportion of soil matrix flow, longer soil water residence times and seasonal variability in soil-P saturation. Here smaller changes in TP loads, predominantly increases, were projected. These results suggest that the clay content of soils could be a good indicator of the sensitivity of catchments to climatic input, and reinforces calls for catchment-specific management plans.

Clinical Impact and Implication of Real-Time Oscillation Analysis for Language Mapping.

PubMed

Ogawa, Hiroshi; Kamada, Kyousuke; Kapeller, Christoph; Prueckl, Robert; Takeuchi, Fumiya; Hiroshima, Satoru; Anei, Ryogo; Guger, Christoph

2017-01-01

We developed a functional brain analysis system that enabled us to perform real-time task-related electrocorticography (ECoG) and evaluated its potential in clinical practice. We hypothesized that high gamma activity (HGA) mapping would provide better spatial and temporal resolution with high signal-to-noise ratios. Seven awake craniotomy patients were evaluated. ECoG was recorded during language tasks using subdural grids, and HGA (60-170 Hz) maps were obtained in real time. The patients also underwent electrocortical stimulation (ECS) mapping to validate the suspected functional locations on HGA mapping. The results were compared and calculated to assess the sensitivity and specificity of HGA mapping. For reference, bedside HGA-ECS mapping was performed in 5 epilepsy patients. HGA mapping demonstrated functional brain areas in real time and was comparable with ECS mapping. Sensitivity and specificity for the language area were 90.1% ± 11.2% and 90.0% ± 4.2%, respectively. Most HGA-positive areas were consistent with ECS-positive regions in both groups, and there were no statistical between-group differences. Although this study included a small number of subjects, it showed real-time HGA mapping with the same setting and tasks under different conditions. This study demonstrates the clinical feasibility of real-time HGA mapping. Real-time HGA mapping enabled simple and rapid detection of language functional areas in awake craniotomy. The mapping results were highly accurate, although the mapping environment was noisy. Further studies of HGA mapping may provide the potential to elaborate complex brain functions and networks. Copyright © 2016 Elsevier Inc. All rights reserved.

Development of an Amperometric Biosensor Platform for the Combined Determination of L-Malic, Fumaric, and L-Aspartic Acid.

PubMed

Röhlen, Désirée L; Pilas, Johanna; Schöning, Michael J; Selmer, Thorsten

2017-10-01

Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD + ) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM -1 (L-malate biosensor) and 0.4 μA mM -1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0-10.0 mM with a sensitivity of 0.09 μA mM -1 . The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.

Dynamic brain connectivity is a better predictor of PTSD than static connectivity.

PubMed

Jin, Changfeng; Jia, Hao; Lanka, Pradyumna; Rangaprakash, D; Li, Lingjiang; Liu, Tianming; Hu, Xiaoping; Deshpande, Gopikrishna

2017-09-01

Using resting-state functional magnetic resonance imaging, we test the hypothesis that subjects with post-traumatic stress disorder (PTSD) are characterized by reduced temporal variability of brain connectivity compared to matched healthy controls. Specifically, we test whether PTSD is characterized by elevated static connectivity, coupled with decreased temporal variability of those connections, with the latter providing greater sensitivity toward the pathology than the former. Static functional connectivity (FC; nondirectional zero-lag correlation) and static effective connectivity (EC; directional time-lagged relationships) were obtained over the entire brain using conventional models. Dynamic FC and dynamic EC were estimated by letting the conventional models to vary as a function of time. Statistical separation and discriminability of these metrics between the groups and their ability to accurately predict the diagnostic label of a novel subject were ascertained using separate support vector machine classifiers. Our findings support our hypothesis that PTSD subjects have stronger static connectivity, but reduced temporal variability of connectivity. Further, machine learning classification accuracy obtained with dynamic FC and dynamic EC was significantly higher than that obtained with static FC and static EC, respectively. Furthermore, results also indicate that the ease with which brain regions engage or disengage with other regions may be more sensitive to underlying pathology than the strength with which they are engaged. Future studies must examine whether this is true only in the case of PTSD or is a general organizing principle in the human brain. Hum Brain Mapp 38:4479-4496, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Antioxidant enzymatic activity is linked to waterlogging stress tolerance in citrus.

PubMed

Arbona, Vicent; Hossain, Zahed; López-Climent, María F; Pérez-Clemente, Rosa M; Gómez-Cadenas, Aurelio

2008-04-01

Soil flooding constitutes a seasonal factor that negatively affects plant performance and crop yields. In this work, the relationship between oxidative damage and flooding sensitivity was addressed in three citrus genotypes with different abilities to tolerate waterlogging. We examined leaf visible damage, oxidative damage in terms of malondialdehyde (MDA) concentration, leaf proline concentration, leaf and root ascorbate and glutathione contents and the antioxidant enzyme activities superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11), catalase (EC 1.11.1.6) and glutathione reductase (EC 1.8.1.7). No differences in the extent of oxidative damage relative to controls were found among genotypes. However, a different ability to delay the apparition of oxidative damage was associated to a higher tolerance to waterlogging. This ability was linked to an enhanced activated oxygen species' scavenging capacity in terms of an increased antioxidant enzyme activity and higher content in polar antioxidant compounds. Therefore, the existence of a direct relationship between stress sensitivity and the early accumulation of MDA is proposed. In addition, data indicate that the protective role of proline has to be considered minimal as its accumulation was inversely correlated with tolerance to the stress. The positive antioxidant response in Carrizo citrange (Poncirus trifoliata L. Raf. x Citrus sinensis L. Osb.) and Citrumelo CPB 4475 (Poncirus trifoliata L. Raf. x Citrus paradisi L. Macf.) might be responsible for a higher tolerance to flooding stress, whereas in Cleopatra mandarin (Citrus reshni Hort. Ex Tan.), the early accumulation of MDA seems to be associated to an impaired ability for H2O2 scavenging.

Factors influencing teamwork and collaboration within a tertiary medical center

PubMed Central

Chien, Shu Feng; Wan, Thomas TH; Chen, Yu-Chih

2012-01-01

AIM: To understand how work climate and related factors influence teamwork and collaboration in a large medical center. METHODS: A survey of 3462 employees was conducted to generate responses to Sexton’s Safety Attitudes Questionnaire (SAQ) to assess perceptions of work environment via a series of five-point, Likert-scaled questions. Path analysis was performed, using teamwork (TW) and collaboration (CO) as endogenous variables. The exogenous variables are effective communication (EC), safety culture (SC), job satisfaction (JS), work pressure (PR), and work climate (WC). The measurement instruments for the variables or summated subscales are presented. Reliability of each sub-scale are calculated. Alpha Cronbach coefficients are relatively strong: TW (0.81), CO (0.76), EC (0.70), SC (0.83), JS (0.91), WP (0.85), and WC (0.78). Confirmatory factor analysis was performed for each of these constructs. RESULTS: Path analysis enables to identify statistically significant predictors of two endogenous variables, teamwork and intra-organizational collaboration. Significant amounts of variance in perceived teamwork (R2 = 0.59) and in collaboration (R2 = 0.75) are accounted for by the predictor variables. In the initial model, safety culture is the most important predictor of perceived teamwork, with a β weight of 0.51, and work climate is the most significant predictor of collaboration, with a β weight of 0.84. After eliminating statistically insignificant causal paths and allowing correlated predictors1, the revised model shows that work climate is the only predictor positively influencing both teamwork (β = 0.26) and collaboration (β = 0.88). A relatively weak positive (β = 0.14) but statistically significant relationship exists between teamwork and collaboration when the effects of other predictors are simultaneously controlled. CONCLUSION: Hospital executives who are interested in improving collaboration should assess the work climate to ensure that employees are operating in a setting conducive to intra-organizational collaboration. PMID:25237612

Light-intensity grazing improves alpine meadow productivity and adaption to climate change on the Tibetan Plateau.

PubMed

Zhang, Tao; Zhang, Yangjian; Xu, Mingjie; Zhu, Juntao; Wimberly, Michael C; Yu, Guirui; Niu, Shuli; Xi, Yi; Zhang, Xianzhou; Wang, Jingsheng

2015-10-30

To explore grazing effects on carbon fluxes in alpine meadow ecosystems, we used a paired eddy-covariance (EC) system to measure carbon fluxes in adjacent fenced (FM) and grazed (GM) meadows on the Tibetan plateau. Gross primary productivity (GPP) and ecosystem respiration (Re) were greater at GM than FM for the first two years of fencing. In the third year, the productivity at FM increased to a level similar to the GM site. The higher productivity at GM was mainly caused by its higher photosynthetic capacity. Grazing exclusion did not increase carbon sequestration capacity for this alpine grassland system. The higher optimal photosynthetic temperature and the weakened ecosystem response to climatic factors at GM may help to facilitate the adaption of alpine meadow ecosystems to changing climate.

Plio-Pleistocene climate sensitivity evaluated using high-resolution CO2 records

NASA Astrophysics Data System (ADS)

Martínez-Botí, M. A.; Foster, G. L.; Chalk, T. B.; Rohling, E. J.; Sexton, P. F.; Lunt, D. J.; Pancost, R. D.; Badger, M. P. S.; Schmidt, D. N.

2015-02-01

Theory and climate modelling suggest that the sensitivity of Earth's climate to changes in radiative forcing could depend on the background climate. However, palaeoclimate data have thus far been insufficient to provide a conclusive test of this prediction. Here we present atmospheric carbon dioxide (CO2) reconstructions based on multi-site boron-isotope records from the late Pliocene epoch (3.3 to 2.3 million years ago). We find that Earth's climate sensitivity to CO2-based radiative forcing (Earth system sensitivity) was half as strong during the warm Pliocene as during the cold late Pleistocene epoch (0.8 to 0.01 million years ago). We attribute this difference to the radiative impacts of continental ice-volume changes (the ice-albedo feedback) during the late Pleistocene, because equilibrium climate sensitivity is identical for the two intervals when we account for such impacts using sea-level reconstructions. We conclude that, on a global scale, no unexpected climate feedbacks operated during the warm Pliocene, and that predictions of equilibrium climate sensitivity (excluding long-term ice-albedo feedbacks) for our Pliocene-like future (with CO2 levels up to maximum Pliocene levels of 450 parts per million) are well described by the currently accepted range of an increase of 1.5 K to 4.5 K per doubling of CO2.

Climate Change, Soils, and Human Health

NASA Astrophysics Data System (ADS)

Brevik, Eric C.

2013-04-01

According to the Intergovernmental Panel on Climate Change, global temperatures are expected to increase 1.1 to 6.4 degrees C during the 21st century and precipitation patterns will be altered by climate change (IPCC, 2007). Soils are intricately linked to the atmospheric/climate system through the carbon, nitrogen, and hydrologic cycles. Altered climate will, therefore, have an effect on soil processes and properties. Studies into the effects of climate change on soil processes and properties are still incomplete, but have revealed that climate change will impact soil organic matter dynamics including soil organisms and the multiple soil properties that are tied to organic matter, soil water, and soil erosion. The exact direction and magnitude of those impacts will be dependent on the amount of change in atmospheric gases, temperature, and precipitation amounts and patterns. Recent studies give reason to believe at least some soils may become net sources of atmospheric carbon as temperatures rise; this is particularly true of high latitude regions with permanently frozen soils. Soil erosion by both wind and water is also likely to increase. These soil changes will lead to both direct and indirect impacts on human health. Possible indirect impacts include temperature extremes, food safety and air quality issues, increased and/or expanded disease incidences, and occupational health issues. Potential direct impacts include decreased food security and increased atmospheric dust levels. However, there are still many things we need to know more about. How climate change will affect the nitrogen cycle and, in turn, how the nitrogen cycle will affect carbon sequestration in soils is a major research need, as is a better understanding of soil water-CO2 level-temperature relationships. Knowledge of the response of plants to elevated atmospheric CO2 given limitations in nutrients like nitrogen and phosphorus and how that affects soil organic matter dynamics is a critical need. There is also a great need for a better understanding of how soil organisms will respond to climate change because those organisms are incredibly important in a number of soil processes, including the carbon and nitrogen cycles. All of these questions are important in trying to understand human health impacts. More information on climate change, soils, and human health issues can be found in Brevik (2012). References Brevik, E.C. 2012. Climate change, soils, and human health. In: E.C. Brevik and L. Burgess (Eds). Soils and human health. CRC Press, Boca Raton, FL. in press. IPCC. 2007. Summary for policymakers. pp. 1-18. In S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds). Climate change 2007: the physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK.

LLNA variability: An essential ingredient for a comprehensive assessment of non-animal skin sensitization test methods and strategies.

PubMed

Hoffmann, Sebastian

2015-01-01

The development of non-animal skin sensitization test methods and strategies is quickly progressing. Either individually or in combination, the predictive capacity is usually described in comparison to local lymph node assay (LLNA) results. In this process the important lesson from other endpoints, such as skin or eye irritation, to account for variability reference test results - here the LLNA - has not yet been fully acknowledged. In order to provide assessors as well as method and strategy developers with appropriate estimates, we investigated the variability of EC3 values from repeated substance testing using the publicly available NICEATM (NTP Interagency Center for the Evaluation of Alternative Toxicological Methods) LLNA database. Repeat experiments for more than 60 substances were analyzed - once taking the vehicle into account and once combining data over all vehicles. In general, variability was higher when different vehicles were used. In terms of skin sensitization potential, i.e., discriminating sensitizer from non-sensitizers, the false positive rate ranged from 14-20%, while the false negative rate was 4-5%. In terms of skin sensitization potency, the rate to assign a substance to the next higher or next lower potency class was approx.10-15%. In addition, general estimates for EC3 variability are provided that can be used for modelling purposes. With our analysis we stress the importance of considering the LLNA variability in the assessment of skin sensitization test methods and strategies and provide estimates thereof.

Use of Questionnaire-Based Measures in the Assessment of Listening Difficulties in School-Aged Children

PubMed Central

Tomlin, Danielle; Moore, David R.; Dillon, Harvey

2015-01-01

Objectives: In this study, the authors assessed the potential utility of a recently developed questionnaire (Evaluation of Children’s Listening and Processing Skills [ECLiPS]) for supporting the clinical assessment of children referred for auditory processing disorder (APD). Design: A total of 49 children (35 referred for APD assessment and 14 from mainstream schools) were assessed for auditory processing (AP) abilities, cognitive abilities, and symptoms of listening difficulty. Four questionnaires were used to capture the symptoms of listening difficulty from the perspective of parents (ECLiPS and Fisher’s auditory problem checklist), teachers (Teacher’s Evaluation of Auditory Performance), and children, that is, self-report (Listening Inventory for Education). Correlation analyses tested for convergence between the questionnaires and both cognitive and AP measures. Discriminant analyses were performed to determine the best combination of tests for discriminating between typically developing children and children referred for APD. Results: All questionnaires were sensitive to the presence of difficulty, that is, children referred for assessment had significantly more symptoms of listening difficulty than typically developing children. There was, however, no evidence of more listening difficulty in children meeting the diagnostic criteria for APD. Some AP tests were significantly correlated with ECLiPS factors measuring related abilities providing evidence for construct validity. All questionnaires correlated to a greater or lesser extent with the cognitive measures in the study. Discriminant analysis suggested that the best discrimination between groups was achieved using a combination of ECLiPS factors, together with nonverbal Intelligence Quotient (cognitive) and AP measures (i.e., dichotic digits test and frequency pattern test). Conclusions: The ECLiPS was particularly sensitive to cognitive difficulties, an important aspect of many children referred for APD, as well as correlating with some AP measures. It can potentially support the preliminary assessment of children referred for APD. PMID:26002277

Automated swimming activity monitor for examining temporal patterns of toxicant effects on individual Daphnia magna.

PubMed

Bahrndorff, Simon; Michaelsen, Thomas Yssing; Jensen, Anne; Marcussen, Laurits Faarup; Nielsen, Majken Elley; Roslev, Peter

2016-07-01

Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high-throughput methods for detecting sublethal effects. We have evaluated an automated infra-red (IR) light-based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K2 Cr2 O7 at 15, 20 and 25 °C and 2,4-dichlorophenol at 20 °C. Significant effects (P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K2 Cr2 O7 whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12-18 h. A similar biphasic pattern was observed after 2,4-dichlorophenol exposure at 20 °C. EC50 values for 2,4-dichlorophenol and K2 Cr2 O7 determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC50 of 0.03-0.07 mg l(-1) h(-1) . EC50 values determined after 48 h were comparable or lower than EC50 values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high-throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Quantifying population exposure to airborne particulate matter during extreme events in California due to climate change

NASA Astrophysics Data System (ADS)

Mahmud, A.; Hixson, M.; Kleeman, M. J.

2012-02-01

The effect of climate change on population-weighted concentrations of particulate matter (PM) during extreme events was studied using the Parallel Climate Model (PCM), the Weather Research and Forecasting (WRF) model and the UCD/CIT 3-D photochemical air quality model. A "business as usual" (B06.44) global emissions scenario was dynamically downscaled for the entire state of California between the years 2000-2006 and 2047-2053. Air quality simulations were carried out for 1008 days in each of the present-day and future climate conditions using year-2000 emissions. Population-weighted concentrations of PM0.1, PM2.5, and PM10 total mass, components species, and primary source contributions were calculated for California and three air basins: the Sacramento Valley air basin (SV), the San Joaquin Valley air basin (SJV) and the South Coast Air Basin (SoCAB). Results over annual-average periods were contrasted with extreme events. Climate change between 2000 vs. 2050 did not cause a statistically significant change in annual-average population-weighted PM2.5 mass concentrations within any major sub-region of California in the current study. Climate change did alter the annual-average composition of the airborne particles in the SoCAB, with notable reductions of elemental carbon (EC; -3%) and organic carbon (OC; -3%) due to increased annual-average wind speeds that diluted primary concentrations from gasoline combustion (-3%) and food cooking (-4%). In contrast, climate change caused significant increases in population-weighted PM2.5 mass concentrations in central California during extreme events. The maximum 24-h average PM2.5 concentration experienced by an average person during a ten-year period in the SJV increased by 21% due to enhanced production of secondary particulate matter (manifested as NH4NO3). In general, climate change caused increased stagnation during future extreme pollution events, leading to higher exposure to diesel engines particles (+32%) and wood combustion particles (+14%) when averaging across the population of the entire state. Enhanced stagnation also isolated populations from distant sources such as shipping (-61%) during extreme events. The combination of these factors altered the statewide population-averaged composition of particles during extreme events, with EC increasing by 23%, nitrate increasing by 58%, and sulfate decreasing by 46%.

Quantifying population exposure to airborne particulate matter during extreme events in California due to climate change

NASA Astrophysics Data System (ADS)

Mahmud, A.; Hixson, M.; Kleeman, M. J.

2012-08-01

The effect of climate change on population-weighted concentrations of particulate matter (PM) during extreme pollution events was studied using the Parallel Climate Model (PCM), the Weather Research and Forecasting (WRF) model and the UCD/CIT 3-D photochemical air quality model. A "business as usual" (B06.44) global emissions scenario was dynamically downscaled for the entire state of California between the years 2000-2006 and 2047-2053. Air quality simulations were carried out for 1008 days in each of the present-day and future climate conditions using year-2000 emissions. Population-weighted concentrations of PM0.1, PM2.5, and PM10 total mass, components species, and primary source contributions were calculated for California and three air basins: the Sacramento Valley air basin (SV), the San Joaquin Valley air basin (SJV) and the South Coast Air Basin (SoCAB). Results over annual-average periods were contrasted with extreme events. The current study found that the change in annual-average population-weighted PM2.5 mass concentrations due to climate change between 2000 vs. 2050 within any major sub-region in California was not statistically significant. However, climate change did alter the annual-average composition of the airborne particles in the SoCAB, with notable reductions of elemental carbon (EC; -3%) and organic carbon (OC; -3%) due to increased annual-average wind speeds that diluted primary concentrations from gasoline combustion (-3%) and food cooking (-4%). In contrast, climate change caused significant increases in population-weighted PM2.5 mass concentrations in central California during extreme events. The maximum 24-h average PM2.5 concentration experienced by an average person during a ten-yr period in the SJV increased by 21% due to enhanced production of secondary particulate matter (manifested as NH4NO3). In general, climate change caused increased stagnation during future extreme pollution events, leading to higher exposure to diesel engines particles (+32%) and wood combustion particles (+14%) when averaging across the population of the entire state. Enhanced stagnation also isolated populations from distant sources such as shipping (-61%) during extreme events. The combination of these factors altered the statewide population-averaged composition of particles during extreme events, with EC increasing by 23 %, nitrate increasing by 58%, and sulfate decreasing by 46%.

Climate Change Impact on Air Quality in High Resolution Simulation for Central Europe

NASA Astrophysics Data System (ADS)

Halenka, T.; Huszar, P.; Belda, M.

2009-04-01

Recently the effects of climate change on air-quality and vice-versa are studied quite extensively. In fact, even at regional and local scale especially the impact of climate change on the atmospheric composition and photochemical smog formation conditions can be significant when expecting e.g. more frequent appearance of heat waves etc. For the purpose of qualifying and quantifying the magnitude of such effects and to study the potential of climate forcing due to atmospheric chemistry/aerosols on regional scale, chemistry-transport model was coupled to RegCM on the Department of Meteorology and Environmental Protection, Faculty of Mathematics and Physics, Charles University in Prague, for the simulations in framework of the EC FP6 Project CECILIA. Off-line one way coupling enables the simulation of distribution of pollutants over 1991-2001 in very high resolution of 10 km is compared to the EMEP observations for the area of Central Europe. Simulations driven by climate change boundary conditions for time slices 1991-2000, 2041-2050 and 2091-2100 are presented to show the effect of climate change on the air quality in the region.

Caveolin-1 regulates lipid droplet metabolism in endothelial cells via autocrine prostacyclin-stimulated, cAMP-mediated lipolysis.

PubMed

Kuo, Andrew; Lee, Monica Y; Yang, Kui; Gross, Richard W; Sessa, William C

2018-01-19

Lipid droplets (LD) are dynamic organelles involved in intracellular lipid metabolism in almost all eukaryotic cells, and LD-associated proteins tightly regulate their dynamics. One LD coat protein is caveolin-1 (Cav-1), an essential component for caveola assembly in highly differentiated cells, including adipocytes, smooth muscle cells, and endothelial cells (EC). However, the role of Cav-1 in LD dynamics is unclear. Here we report that EC lacking Cav-1 exhibit impaired LD formation. The decreased LD formation is due to enhanced lipolysis and not caused by reduced triglyceride synthesis or fatty acid uptake. Mechanistically, the absence of Cav-1 increased cAMP/PKA signaling in EC, as indicated by elevated phosphorylation of hormone-sensitive lipase and increased lipolysis. Unexpectedly, we also observed enhanced autocrine production of prostaglandin I 2 (PGI 2 , also called prostacyclin) in Cav-1 KO EC, and this PGI 2 increase appeared to stimulate cAMP/PKA pathways, contributing to the enhanced lipolysis in Cav-1 KO cells. Our results reveal an unanticipated role of Cav-1 in regulating lipolysis in non-adipose tissue, indicating that Cav-1 is required for LD metabolism in EC and that it regulates cAMP-dependent lipolysis in part via the autocrine production of PGI 2 .

Thinning increases climatic resilience of red pine

USGS Publications Warehouse

Magruder, Matthew; Chhin, Sophan; Palik, Brian; Bradford, John B.

2013-01-01

Forest management techniques such as intermediate stand-tending practices (e.g., thinning) can promote climatic resiliency in forest stands by moderating tree competition. Residual trees gain increased access to environmental resources (i.e., soil moisture, light), which in turn has the potential to buffer trees from stressful climatic conditions. The influences of climate (temperature and precipitation) and forest management (thinning method and intensity) on the productivity of red pine (Pinus resinosa Ait.) in Michigan were examined to assess whether repeated thinning treatments were able to increase climatic resiliency (i.e., maintaining productivity and reduced sensitivity to climatic stress). The cumulative productivity of each thinning treatment was determined, and it was found that thinning from below to a residual basal area of 14 m2·ha−1 produced the largest average tree size but also the second lowest overall biomass per acre. On the other hand, the uncut control and the thinning from above to a residual basal area of 28 m2·ha−1 produced the smallest average tree size but also the greatest overall biomass per acre. Dendrochronological methods were used to quantify sensitivity of annual radial growth to monthly and seasonal climatic factors for each thinning treatment type. Climatic sensitivity was influenced by thinning method (i.e., thinning from below decreased sensitivity to climatic stress more than thinning from above) and by thinning intensity (i.e., more intense thinning led to a lower climatic sensitivity). Overall, thinning from below to a residual basal area of 21 m2·ha−1 represented a potentially beneficial compromise to maximize tree size, biomass per acre, and reduced sensitivity to climatic stress, and, thus, the highest level of climatic resilience.

AMS Professional Development Courses: Arming K-12 Teachers with the Tools Needed to Increase Students' Scientific Literacy

NASA Astrophysics Data System (ADS)

Brey, J. A.; Geer, I. W.; Weinbeck, R. S.; Moran, J. M.; Nugnes, K. A.

2012-12-01

To better prepare tomorrow's leaders, it is of utmost importance that today's teachers are science literate. To meet that need, the American Meteorological Society (AMS) Education Program offers content-rich, professional development courses and training workshops for precollege teachers in the geosciences. During the fall and spring semesters, the AMS in partnership with NOAA, NASA, and SUNY Brockport, offers a suite of pre-college teacher development courses, DataStreme Atmosphere, DataStreme Ocean and DataStreme Earth's Climate System (ECS). These courses are delivered to small groups of K-12 teachers through Local Implementation Teams (LITs) positioned throughout the U.S. The courses use current, real-world environmental data to investigate the atmosphere, ocean, and climate system and consist of weekly online study materials, weekly mentoring, and several face-to-face meetings, all supplemented by a provided textbook and investigations manual. DataStreme ECS takes an innovative approach to studying climate science, by exploring the fundamental science of Earth's climate system and addressing the societal impacts relevant to today's students and teachers. The course investigates natural and human forcings and feedbacks to examine mitigation and adaptation strategies for the future. Information and data from respected organizations, such as the IPCC, the US Global Change Research Program, NASA, and NOAA are used throughout the course, including in the online and printed investigations. In addition, participants differentiate between climate, climate variability, and climate change through the AMS Conceptual Energy Model, a basic climate model that follows the flow of energy from space to Earth and back. Participants also have access to NASA's EdGCM, a research-grade Global Climate Model where they can explore various future climate scenarios in the same way that actual research scientists do. Throughout all of the courses, teachers have the opportunity to expand their knowledge in the geosciences and incorporate technology into their classrooms by utilizing state-of-the-art resources from NOAA, NASA, and other lead scientific organizations. Upon completion of each course, teachers receive three free graduate credits from SUNY Brockport. The DataStreme courses have directly trained almost 17,000 teachers, impacting over one million students. The DataStreme courses have increased teachers' geoscience knowledge, pointing them to the resources available online, and building their confidence in understanding dynamic Earth systems. Through courses modeled on scientific inquiry and fashioned to develop critical thinking skills, these teachers become a resource for their classrooms and colleagues.

Identification of specific malformations of sea urchin larvae for toxicity assessment: application to marine pisciculture effluents.

PubMed

Carballeira, C; Ramos-Gómez, J; Martín-Díaz, L; DelValls, T A

2012-06-01

Standard toxicity screening tests are useful tools in the management of impacted coastal ecosystems. To our knowledge, this is the first time that the sea urchin embryo development test has been used to evaluate the potential impact of effluents from land-based aquaculture farms in coastal areas. The toxicity of effluents from 8 land-based turbot farms was determined by calculating the percentage of abnormal larvae, according to two criteria: (a) standard, considering as normal pyramid-shaped larvae with differentiated components, and (b) skeletal, a new criterion that considers detailed skeletal characteristics. The skeletal criterion appeared to be more sensitive and enabled calculation of effective concentrations EC(5), EC(10), EC(20) and EC(50), unlike the classical criterion. Inclusion of the skeleton criterion in the sea urchin embryo development test may be useful for categorizing the relatively low toxicity of discharges from land-based marine fish farms. Further studies are encouraged to establish any causative relationships between pollutants and specific larval deformities. Copyright © 2012 Elsevier Ltd. All rights reserved.

Cue competition in evaluative conditioning as a function of the learning process.

PubMed

Kattner, Florian; Green, C Shawn

2015-11-01

Evaluative conditioning (EC) is the change in the valence of a stimulus resulting from pairings with an affective (unconditioned) stimulus (US). With some exceptions, previous work has indicated that this form of conditioning might be insensitive to cue competition effects such as blocking and overshadowing. Here we assessed whether the extent of cue competition in EC depends upon the type of contingency learning during conditioning. Specifically, we contrasted a learning task that biased participants toward cognitive/inferential learning (i.e., predicting the US) with a learning task that prevented prolonged introspection (i.e., a rapid response made to the US). In all cases, standard EC effects were observed, with the subjective liking of stimuli changed in the direction of the valence of the US. More importantly, when inferential learning was likely, larger EC effects occurred for isolated stimuli than for compounds (indicating overshadowing). No blocking effects on explicit evaluations were observed for either learning task. Contingency judgments and implicit evaluations, however, were sensitive to blocking, indicating that the absence of a blocking effect on explicit evaluations might be due to inferences that occur during testing.

Climate change and children.

PubMed

Ebi, Kristie L; Paulson, Jerome A

2007-04-01

Climate change is increasing the burden of climate-sensitive health determinants and outcomes worldwide. Acting through increasing temperature, changes in the hydrologic cycle, and sea level rise, climate change is projected to increase the frequency and intensity of heat events and extreme events (floods and droughts), change the geographic range and incidence of climate-sensitive vector-, food-, and waterborne diseases, and increase diseases associated with air pollution and aeroallergens. Children are particularly vulnerable to these health outcomes because of their potentially greater exposures, greater sensitivity to certain exposures, and their dependence on caregivers.

Increased sensitivity to proactive and retroactive interference in amnestic mild cognitive impairment: new insights.

PubMed

Hanseeuw, Bernard J; Seron, Xavier; Ivanoiu, Adrian

2012-10-01

Increased sensitivity to proactive (PI) and retroactive (RI) interference has been observed in amnestic mild cognitive impairment (aMCI). PI and RI are often explained as being the result of a response competition mechanism. However, patients with aMCI are supposed to suffer mostly from encoding deficits. We hypothesized that in aMCI interference may occur at encoding and not only at the retrieval stage. We developed an original paradigm enabling PI and RI to be tested with and without response competitors. Eighteen young controls (YC), 16 elderly controls (EC) and 15 aMCI participated in the study. The YC and EC groups presented interference effects only in conditions that included a direct response competitor. In contrast, aMCI had interference effects in all conditions including the one without response competitor. Increased sensitivity to interference in aMCI appears to occur at the encoding/consolidation stage and not only at the retrieval stage, as is the case in healthy subjects. This result is discussed in the context of the associative encoding deficits characterizing aMCI. Copyright © 2012 Elsevier Inc. All rights reserved.

Nano-titanium dioxide modulates the dermal sensitization potency of DNCB

PubMed Central

2012-01-01

We determined the ability of a model nanoparticle (NP) (titanium dioxide, TiO2) to modulate sensitization induced by a known potent dermal sensitizer (dinitrochlorobenzene) using a variant of the local lymph node assay called lymph node proliferation assay. BALB/c mice received sub-cutaneous injections of vehicle (2.5 mM sodium citrate), TiO2 NPs (0.004, 0.04 or 0.4 mg/ml) or pigment particles (0.04 mg/ml) both stabilized in sodium citrate buffer at the base of each ear (2x50μl), before receiving dermal applications (on both ears) of 2,4-Dinitrochlorobenzene (DNCB) (2x25μl of 0.1%) or its vehicle (acetone olive oil – AOO (4:1)) on days 0, 1 and 2. On day 5, the stimulation index (SI) was calculated as a ratio of 3HTdR incorporation in lymphocytes from DNBC-treated mice and AOO-treated controls. In a second experiment the EC3-value for DNCB (0 to 0.1%) was assessed in the absence or presence of 0.04 mg/ml TiO2. In a third experiment, the lymphocyte subpopulations and the cytokine secretion profile were analyzed after TiO2 (0.04 mg/ml) and DNCB (0.1%) treatment. Injection of NPs in AOO-treated control mice did not have any effect on lymph node (LN) proliferation. DNCB sensitization resulted in LN proliferation, which was further increased by injection of TiO2 NPs before DNCB sensitization. The EC3 of DNCB, with prior injection of vehicle control was 0.041%, while injection with TiO2 decreased the EC3 of DNCB to 0.015%. TiO2 NPs pre-treatment did not alter the lymphocyte subpopulations, but significantly increased the level of IL-4 and decreased IL-10 production in DNCB treated animals. In conclusion, our study demonstrates that administration of nano-TiO2 increases the dermal sensitization potency of DNCB, by augmenting a Th2 response, showing the immunomodulatory abilities of NPs. PMID:22621278

Higher climatological temperature sensitivity of soil carbon in cold than warm climates

NASA Astrophysics Data System (ADS)

Koven, Charles D.; Hugelius, Gustaf; Lawrence, David M.; Wieder, William R.

2017-11-01

The projected loss of soil carbon to the atmosphere resulting from climate change is a potentially large but highly uncertain feedback to warming. The magnitude of this feedback is poorly constrained by observations and theory, and is disparately represented in Earth system models (ESMs). To assess the climatological temperature sensitivity of soil carbon, we calculate apparent soil carbon turnover times that reflect long-term and broad-scale rates of decomposition. Here, we show that the climatological temperature control on carbon turnover in the top metre of global soils is more sensitive in cold climates than in warm climates and argue that it is critical to capture this emergent ecosystem property in global-scale models. We present a simplified model that explains the observed high cold-climate sensitivity using only the physical scaling of soil freeze-thaw state across climate gradients. Current ESMs fail to capture this pattern, except in an ESM that explicitly resolves vertical gradients in soil climate and carbon turnover. An observed weak tropical temperature sensitivity emerges in a different model that explicitly resolves mineralogical control on decomposition. These results support projections of strong carbon-climate feedbacks from northern soils and demonstrate a method for ESMs to capture this emergent behaviour.

Educational climate perception by preclinical and clinical medical students in five Spanish medical schools.

PubMed

Palés, Jorge; Gual, Arcadi; Escanero, Jesús; Tomás, Inmaculada; Rodríguez-de Castro, Felipe; Elorduy, Marta; Virumbrales, Montserrat; Rodríguez, Gerardo; Arce, Víctor

2015-06-08

The purpose of this study was to investigate student's perceptions of Educational Climate (EC) in Spanish medical schools, comparing various aspects of EC between the 2nd (preclinical) and the 4th (clinical) years to detect strengths and weaknesses in the on-going curricular reform. This study utilized a cross-sectional design and employed the Spanish version of the "Dundee Ready Education Environment Measure" (DREEM). The survey involved 894 2nd year students and 619 4th year students from five Spanish medical schools. The global average score of 2nd year students from the five medical schools was found to be significantly higher (116.2±24.9, 58.2% of maximum score) than that observed in 4th year students (104.8±29.5, 52.4% of maximum score). When the results in each medical school were analysed separately, the scores obtained in the 2nd year were almost always significantly higher than in the 4th year for all medical schools, in both the global scales and the different subscales. The perception of the EC by 2nd and 4th year students from five Spanish medical schools is more positive than negative although it is significantly lower in the 4th year. In both years, although more evident in the 4th year, students point out the existence of several important "problematic educational areas" associated with the persistence of traditional curricula and teaching methodologies. Our findings of this study should lead medical schools to make a serious reflection and drive the implementation of the necessary changes required to improve teaching, especially during the clinical period.

Educational climate perception by preclinical and clinical medical students in five Spanish medical schools

PubMed Central

Gual, Arcadi; Escaneroi, Jesus; Tomás, Inmaculada; Rodríguez de Castro, Felipe; Elorudy, Marta; Virumbrales, Montserrat; Rodríguez, Gerardo; Arce, Victor

2015-01-01

Objectives The purpose of this study was to investigate student's perceptions of Educational Climate (EC) in Spanish medical schools, comparing various aspects of EC between the 2nd (preclinical) and the 4th (clinical) years to detect strengths and weaknesses in the on-going curricular reform. Methods This study utilized a cross-sectional design and employed the Spanish version of the "Dundee Ready Education Environment Measure" (DREEM). The survey involved 894 2nd year students and 619 4th year students from five Spanish medical schools. Results The global average score of 2nd year students from the five medical schools was found to be significantly higher (116.2±24.9, 58.2% of maximum score) than that observed in 4th year students (104.8±29.5, 52.4% of maximum score). When the results in each medical school were analysed separately, the scores obtained in the 2nd year were almost always significantly higher than in the 4th year for all medical schools, in both the global scales and the different subscales. Conclusions The perception of the EC by 2nd and 4th year students from five Spanish medical schools is more positive than negative although it is significantly lower in the 4th  year. In both years, although more evident in the 4th year, students point out the existence of several important "problematic educational areas" associated with the persistence of traditional curricula and teaching methodologies. Our findings of this study should lead medical schools to make a serious reflection and drive the implementation of the necessary changes required to improve teaching, especially during the clinical period. PMID:26057355

Unravel biophysical factors on river water quality response in Chilean Central-Southern watersheds.

PubMed

Yevenes, Mariela A; Arumí, José L; Farías, Laura

2016-05-01

Identifying the key anthropogenic (land uses) and natural (topography and climate) biophysical drivers affecting river water quality is essential for efficient management of water resources. We tested the hypothesis that water quality can be predicted by different biophysical factors. Multivariate statistics based on a geographical information system (GIS) were used to explore the influence of factors (i.e., precipitation, topography, and land uses) on water quality (i.e., nitrate (NO 3 (-)), phosphate (PO 4 (3-)), silicate (Si(OH)4), dissolved oxygen (DO), suspended solids (TSS), biological oxygen demand (DO), temperature (T), conductivity (EC), and pH) for two consecutive years in the Itata and Biobío river watersheds, Central Chile (36° 00' and 38° 30'). The results showed that (NO 3 (-)), (PO 4 (3-)), Si(OH)4, TSS, EC, and DO were higher during rainy season (austral fall, winter, and spring), whereas BOD and temperature were higher during dry season. The spatial variation of these parameters in both watersheds was related to land use, topography (e.g., soil moisture, soil hydrological group, and erodability), and precipitation. Soil hydrological group and soil moisture were the strongest explanatory predictors for PO 4 (3-) , Si(OH)4 and EC in the river, followed by land use such as agriculture for NO 3 (-) and DO and silviculture for TSS and Si(OH)4. High-resolution water leaching and runoff maps allowed us to identify agriculture areas with major probability of water leaching and higher probability of runoff in silviculture areas. Moreover, redundancy analysis (RDA) revealed that land uses (agriculture and silviculture) explained in 60 % the river water quality variation. Our finding highlights the vulnerability of Chilean river waters to different biophysical drivers, rather than climate conditions alone, which is amplified by human-induced degradation.

The influence of climate regime shifts on the marine environment and ecosystems in the East Asian Marginal Seas and their mechanisms

NASA Astrophysics Data System (ADS)

Kun Jung, Hae; Rahman, SM Mustafizur; Kang, Chang-Keun; Park, Se-Young; Heon Lee, Sang; Je Park, Hyun; Kim, Hyun-Woo; Il Lee, Chung

2017-09-01

Step changes to seawater temperature (SWT) in the East Asian marginal seas (EAMS) are associated with three recent climate regime shifts (CRS) occurring in the mid-1970s, late 1980s, and late 1990s, but the responses of the ocean conditions and marine ecosystems had regional differences. A step change in SWT in the East China Sea (ECS) was detected after the CRS of the 1970s as were step changes in the North Pacific Index (NPI), Pacific Decadal Oscillation Index (PDOI), and East Asian Winter Monsoon Index (EAWMI). SWT in the ECS decreased with decreasing warm water volume transport into the EAMS and a strong monsoon, but step changes in SWT in other regions were not detected as clearly. After the CRS of the 1980s, SWT in all EAMS increased rapidly with step changes detected in all five climate indices examined. These changes were associated with a weak winter monsoon, increasing surface air temperature (SAT), and increasing warm water volume transport into the EAMS. However, after the CRS of the 1990s, a decrease in SWT around the EAMS was detected in the northern part of East China Sea (NECS), and the ECS with step changes also in the EAWMI and the Arctic Oscillation Index (AOI). In contrast, SWT in the East Sea/Sea of Japan (EJS) and the Yellow Sea (YS) continuously increased during this time. Long-term changes in zooplankton biomass were affected by regional differences in the responses of atmospheric and oceanic variability to CRSs. Specifically, long-term changes in the timing of peaks in zooplankton abundances exhibited differences. During warm periods (e.g. after the 1980s CRS) in the EJS, the amount of zooplankton biomass in October increased, while in February it decreased. On the contrary, in the YS and the NECS, the peaks of October and June in zooplankton biomass occurred during cold periods (after the 1970s and 1990s CRS). Major fisheries resources also responded to the three CRSs, although warm and cold water species responded differently to changes in oceanographic conditions in regional spawning grounds.

The sensitivity of current and future forest managers to climate-induced changes in ecological processes.

PubMed

Seidl, Rupert; Aggestam, Filip; Rammer, Werner; Blennow, Kristina; Wolfslehner, Bernhard

2016-05-01

Climate vulnerability of managed forest ecosystems is not only determined by ecological processes but also influenced by the adaptive capacity of forest managers. To better understand adaptive behaviour, we conducted a questionnaire study among current and future forest managers (i.e. active managers and forestry students) in Austria. We found widespread belief in climate change (94.7 % of respondents), and no significant difference between current and future managers. Based on intended responses to climate-induced ecosystem changes, we distinguished four groups: highly sensitive managers (27.7 %), those mainly sensitive to changes in growth and regeneration processes (46.7 %), managers primarily sensitive to regeneration changes (11.2 %), and insensitive managers (14.4 %). Experiences and beliefs with regard to disturbance-related tree mortality were found to particularly influence a manager's sensitivity to climate change. Our findings underline the importance of the social dimension of climate change adaptation, and suggest potentially strong adaptive feedbacks between ecosystems and their managers.

Abnormalities in the contractile properties of colonic smooth muscle in idiopathic slow transit constipation.

PubMed

Slater, B J; Varma, J S; Gillespie, J I

1997-02-01

The underlying pathophysiology of idiopathic slow transit constipation (ISTC) remains unclear. At present, there is little evidence to implicate a smooth muscle myopathy in the aetiology of this condition. This study compared the effect of cisapride on the cholinergic response of colonic muscle strips from patients with this condition with that of control tissue. Isometric tension production was recorded from circular smooth muscle strips taken from five patients undergoing colectomy for ISTC in response to cumulative concentrations of carbachol (100 nmol/1-100 mumol/l) alone and in the presence of cisapride 400 nmol/l. Similar dose-response activity was obtained for a control group consisting of six patients undergoing resection for colorectal carcinoma. In the absence of cisapride, smooth muscle from patients with carcinoma exhibited a significantly lower sensitivity to cholinergic stimulation (agonist concentration required to produce half-maximal activation (EC50) 4.83 mumol/l) than that from patients with ISTC (EC50 1.63 mumol/l, P = 0.036), and also a greater maximal frequency of the oscillatory activity associated with the increase in isometric tension (0.070 versus 0.049 Hz, P = 0.035). Cisapride had no effect on the sensitivity to carbachol of the carcinoma tissue but brought about a significant reduction in the sensitivity of smooth muscle from patients with ISTC (EC50 3.24 mumol/l, P = 0.043). These findings indicate that colonic smooth muscle from patients with ISTC is hypersensitive to cholinergic stimulation and suggest the existence of a smooth muscle myopathy in this condition.

Inward rectifier potassium (Kir2.1) channels as end‐stage boosters of endothelium‐dependent vasodilators

PubMed Central

Dalsgaard, Thomas; Bonev, Adrian D.; Nelson, Mark T.

2016-01-01

Key points Increase in endothelial cell (EC) calcium activates calcium‐sensitive intermediate and small conductance potassium (IK and SK) channels, thereby causing hyperpolarization and endothelium‐dependent vasodilatation.Endothelial cells express inward rectifier potassium (Kir) channels, but their role in endothelium‐dependent vasodilatation is not clear.In the mesenteric arteries, only ECs, but not smooth muscle cells, displayed Kir currents that were predominantly mediated by the Kir2.1 isoform.Endothelium‐dependent vasodilatations in response to muscarinic receptor, TRPV4 (transient receptor potential vanilloid 4) channel and IK/SK channel agonists were highly attenuated by Kir channel inhibitors and by Kir2.1 channel knockdown.These results point to EC Kir channels as amplifiers of vasodilatation in response to increases in EC calcium and IK/SK channel activation and suggest that EC Kir channels could be targeted to treat endothelial dysfunction, which is a hallmark of vascular disorders. Abstract Endothelium‐dependent vasodilators, such as acetylcholine, increase intracellular Ca2+ through activation of transient receptor potential vanilloid 4 (TRPV4) channels in the plasma membrane and inositol trisphosphate receptors in the endoplasmic reticulum, leading to stimulation of Ca2+‐sensitive intermediate and small conductance K+ (IK and SK, respectively) channels. Although strong inward rectifier K+ (Kir) channels have been reported in the native endothelial cells (ECs) their role in EC‐dependent vasodilatation is not clear. Here, we test the idea that Kir channels boost the EC‐dependent vasodilatation of resistance‐sized arteries. We show that ECs, but not smooth muscle cells, of small mesenteric arteries have Kir currents, which are substantially reduced in EC‐specific Kir2.1 knockdown (EC‐Kir2.1 −/−) mice. Elevation of extracellular K+ to 14 mm caused vasodilatation of pressurized arteries, which was prevented by endothelial denudation and Kir channel inhibitors (Ba2+, ML‐133) or in the arteries from EC‐Kir2.1 −/− mice. Potassium‐induced dilatations were unaffected by inhibitors of TRPV4, IK and SK channels. The Kir channel blocker, Ba2+, did not affect currents through TRPV4, IK or SK channels. Endothelial cell‐dependent vasodilatations in response to activation of muscarinic receptors, TRPV4 channels or IK/SK channels were reduced, but not eliminated, by Kir channel inhibitors or EC‐Kir2.1 −/−. In angiotensin II‐induced hypertension, the Kir channel function was not altered, although the endothelium‐dependent vasodilatation was severely impaired. Our results support the concept that EC Kir2 channels boost vasodilatory signals that are generated by Ca2+‐dependent activation of IK and SK channels. PMID:26840527

Ecosystem effects and the management of petroleum-contaminated soils on subantarctic islands.

PubMed

Errington, Ingrid; King, Catherine K; Wilkins, Daniel; Spedding, Tim; Hose, Grant C

2018-03-01

Human activity in the Polar Regions has resulted in petroleum contamination of soils. In this context, subantarctic islands are a unique management challenge for climatic, biological and logistical reasons. In this review we identify the main abiotic factors affecting petroleum-contaminated soils in the subantarctic environment, the primary effects of such contamination on biota, and lessons learned with regards to remediation techniques in this region. The sensitivity of biota to contamination depends on organism life stage, on soil properties, and on the degree of contaminant weathering. Initial studies using species endemic to subantarctic islands suggest that for fresh diesel fuel, sensitivities may range between 103 and 20 000 mg total petroleum hydrocarbons (TPH) kg -1 soil. Diesel that has undergone a short period of weathering is generally more toxic, with sensitivities ranging between 52 and 13 000 mg TPH kg -1 soil for an earthworm and a grass respectively (based on EC 20 and IC 50 values). A sufficient body of data from which to develop remediation targets for existing spills in the region does not yet exist for the region, but there has been a recent increase in research attention to address this data gap. A range of remediation methods have also now been trialled, and techniques such as in-ground aeration and nutrient addition have achieved some success. Passive management techniques such as permeable reactive barriers and phytoremediation are in preliminary stages of investigation for the region and show promise, not least because they cause less collateral disturbance than other methods. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Sensitivity of Alpine Snow and Streamflow Regimes to Climate Changes

NASA Astrophysics Data System (ADS)

Rasouli, K.; Pomeroy, J. W.; Marks, D. G.; Bernhardt, M.

2014-12-01

Understanding the sensitivity of hydrological processes to climate change in alpine areas with snow dominated regimes is of paramount importance as alpine basins show both high runoff efficiency associated with the melt of the seasonal snowpack and great sensitivity of snow processes to temperature change. In this study, meteorological data measured in a selection of alpine headwaters basins including Reynolds Mountain East, Idaho, USA, Wolf Creek, Yukon in Canada, and Zugspitze Mountain, Germany with climates ranging from arctic to continental temperate were used to study the snow and streamflow sensitivity to climate change. All research sites have detailed multi-decadal meteorological and snow measurements. The Cold Regions Hydrological Modelling platform (CRHM) was used to create a model representing a typical alpine headwater basin discretized into hydrological response units with physically based representations of snow redistribution by wind, complex terrain snowmelt energetics and runoff processes in alpine tundra. The sensitivity of snow hydrology to climate change was investigated by changing air temperature and precipitation using weather generating methods based on the change factors obtained from different climate model projections for future and current periods. The basin mean and spatial variability of peak snow water equivalent, sublimation loss, duration of snow season, snowmelt rates, streamflow peak, and basin discharge were assessed under varying climate scenarios and the most sensitive hydrological mechanisms to the changes in the different alpine climates were detected. The results show that snow hydrology in colder alpine climates is more resilient to warming than that in warmer climates, but that compensatory factors to warming such as reduced blowing snow sublimation loss and reduced melt rate should also be assessed when considering climate change impacts on alpine hydrology.

Interleukin-17 Promotes Neutrophil-Mediated Immunity by Activating Microvascular Pericytes and Not Endothelium

PubMed Central

Liu, Rebecca; Lauridsen, Holly M.; Amezquita, Robert A.; Pierce, Richard W.; Jane-wit, Dan; Fang, Caodi; Pellowe, Amanda S.; Kirkiles-Smith, Nancy C.; Gonzalez, Anjelica L.; Pober, Jordan S.

2016-01-01

A classical hallmark of acute inflammation is neutrophil infiltration of tissues, a multi-step process that involves sequential cell-cell interactions of circulating leukocytes with interleukin (IL)-1- or tumor necrosis factor-α (TNF)-activated microvascular endothelial cells (ECs) and pericytes (PCs) that form the wall of the postcapillary venules. The initial infiltrating cells accumulate perivascularly in close proximity to PCs. IL-17, a pro-inflammatory cytokine that acts on target cells via a heterodimeric receptor formed by IL-17RA and IL-17RC subunits, also promotes neutrophilic inflammation but its effects on vascular cells are less clear. We report that both cultured human ECs and PCs strongly express IL-17RC and, while neither cell type expresses much IL-17RA, PCs express significantly more than ECs. IL-17, alone or synergistically with TNF, significantly alters inflammatory gene expression in cultured human PCs but not ECs. RNA-seq analysis identifies many IL-17-induced transcripts in PCs encoding proteins known to stimulate neutrophil-mediated immunity. Conditioned media (CM) from IL-17-activated PCs, but not ECs, induce pertussis toxin-sensitive neutrophil polarization, likely mediated by PC-secreted chemokines, and also stimulate neutrophil production of pro-inflammatory molecules, including TNF, IL-1α, IL-1β, and IL-8. Furthermore, IL-17-activated PCs but not ECs can prolong neutrophil survival by producing G-CSF and GM-CSF, delaying the mitochondria outer membrane permeabilization and caspase 9 activation. Importantly, neutrophils exhibit enhanced phagocytic capacity after activation by CM from IL-17-treated PCs. We conclude that PCs, not ECs, are the major target of IL-17 within the microvessel wall and that IL-17-activated PCs can modulate neutrophil functions within the perivascular tissue space. PMID:27534549

Docosahexaenoyl ethanolamide improves glucose uptake and alters endocannabinoid system gene expression in proliferating and differentiating C2C12 myoblasts

PubMed Central

Kim, Jeffrey; Carlson, Morgan E.; Watkins, Bruce A.

2014-01-01

Skeletal muscle is a major storage site for glycogen and a focus for understanding insulin resistance and type-2-diabetes. New evidence indicates that overactivation of the peripheral endocannabinoid system (ECS) in skeletal muscle diminishes insulin sensitivity. Specific n-6 and n-3 polyunsaturated fatty acids (PUFA) are precursors for the biosynthesis of ligands that bind to and activate the cannabinoid receptors. The function of the ECS and action of PUFA in skeletal muscle glucose uptake was investigated in proliferating and differentiated C2C12 myoblasts treated with either 25 μM of arachidonate (AA) or docosahexaenoate (DHA), 25 μM of EC [anandamide (AEA), 2-arachidonoylglycerol (2-AG), docosahexaenoylethanolamide (DHEA)], 1 μM of CB1 antagonist NESS0327, and CB2 inverse agonist AM630. Compared to the BSA vehicle control cell cultures in both proliferating and differentiated myoblasts those treated with DHEA, the EC derived from the n-3 PUFA DHA, had higher 24 h glucose uptake, while AEA and 2-AG, the EC derived from the n-6 PUFA AA, had lower basal glucose uptake. Adenylyl cyclase mRNA was higher in myoblasts treated with DHA in both proliferating and differentiated states while those treated with AEA or 2-AG were lower compared to the control cell cultures. Western blot and qPCR analysis showed higher expression of the cannabinoid receptors in differentiated myoblasts treated with DHA while the opposite was observed with AA. These findings indicate a compensatory effect of DHA and DHEA compared to AA-derived ligands on the ECS and associated ECS gene expression and higher glucose uptake in myoblasts. PMID:24711795

Selective neurotensin-derived internally quenched fluorogenic substrates for neurolysin (EC 3.4.24.16): comparison with thimet oligopeptidase (EC 3.4.24.15) and neprilysin (EC 3.4.24.11).

PubMed

Oliveira, V; Campos, M; Hemerly, J P; Ferro, E S; Camargo, A C; Juliano, M A; Juliano, L

2001-05-15

Internally quenched fluorescent peptides derived from neurotensin (pELYENKPRRPYIL) sequence were synthesized and assayed as substrates for neurolysin (EC 3.4.24.16), thimet oligopeptidase (EC 3.4.24.15 or TOP), and neprilysin (EC 3.4.24.11 or NEP). Abz-LYENKPRRPYILQ-EDDnp (where EDDnp is N-(2,4-dinitrophenyl)ethylenediamine and Abz is ortho-aminobenzoic acid) was derived from neurotensin by the introduction of Q-EDDnp at the C-terminal end of peptide and by the substitution of the pyroglutamic (pE) residue at N-terminus for Abz and a series of shorter peptides was obtained by deletion of amino acids residues from C-terminal, N-terminal, or both sides. Neurolysin and TOP hydrolyzed the substrates at P--Y or Y--I or R--R bonds depending on the sequence and size of the peptides, while NEP cleaved P-Y or Y-I bonds according to its S'(1) specificity. One of these substrates, Abz-NKPRRPQ-EDDnp was a specific and sensitive substrate for neurolysin (k(cat) = 7.0 s(-1), K(m) = 1.19 microM and k(cat)/K(m) = 5882 mM(-1). s(-1)), while it was completely resistant to NEP and poorly hydrolyzed by TOP and also by prolyl oligopeptidase (EC 3.4.21.26). Neurolysin concentrations as low as 1 pM were detected using this substrate under our conditions and its analogue Abz-NKPRAPQ-EDDnp was hydrolyzed by neurolysin with k(cat) = 14.03 s(-1), K(m) = 0.82 microM, and k(cat)/K(m) = 17,110 mM(-1). s(-1), being the best substrate so far described for this peptidase. Copyright 2001 Academic Press.

Assessment of sublethal endpoints after chronic exposure of the nematode Caenorhabditis elegans to palladium, platinum and rhodium.

PubMed

Schertzinger, Gerhard; Zimmermann, Sonja; Grabner, Daniel; Sures, Bernd

2017-11-01

The aim of this study was to investigate chronic effects of the platinum-group elements (PGE) palladium (Pd), platinum (Pt) and rhodium (Rh) on the nematode Caenorhabditis elegans. Aquatic toxicity testing was carried out according to ISO 10872 by determining 96 h EC 50 values for sublethal endpoints, including growth, fertility and reproduction. Single PGE standard solutions were used as metal source. Based on the EC 50 values for Pt, reproduction (96 h EC 50  = 497 μg/L) was the most sensitive endpoint followed by fertility (96 h EC 50  = 726 μg/L) and growth (96 h EC 50  = 808 μg/L). For Pd, no precise EC 50 values could be calculated due to bell-shaped concentration response curves, but the 96 h EC 50 for reproduction ranged between 10 and 100 μg/L. Pd and Pt had effects on all endpoints. With raising element concentrations reproduction was inhibited first. At a certain concentration, fertility was also affected, which in turn had an additional effect on reproduction. Growth inhibition can also lead to a loss of fertility if the worms do not reach an appropriate body size to become fertile. Rhodium showed no inhibition of any endpoint between concentrations of 100 to 10,000 μg Rh/L. The results of this study allow the following order of PGE with respect to decreasing toxicity to C. elegans: Pd > Pt » Rh. Copyright © 2017 Elsevier Ltd. All rights reserved.

Plio-Pleistocene climate sensitivity evaluated using high-resolution CO2 records.

PubMed

Martínez-Botí, M A; Foster, G L; Chalk, T B; Rohling, E J; Sexton, P F; Lunt, D J; Pancost, R D; Badger, M P S; Schmidt, D N

2015-02-05

Theory and climate modelling suggest that the sensitivity of Earth's climate to changes in radiative forcing could depend on the background climate. However, palaeoclimate data have thus far been insufficient to provide a conclusive test of this prediction. Here we present atmospheric carbon dioxide (CO2) reconstructions based on multi-site boron-isotope records from the late Pliocene epoch (3.3 to 2.3 million years ago). We find that Earth's climate sensitivity to CO2-based radiative forcing (Earth system sensitivity) was half as strong during the warm Pliocene as during the cold late Pleistocene epoch (0.8 to 0.01 million years ago). We attribute this difference to the radiative impacts of continental ice-volume changes (the ice-albedo feedback) during the late Pleistocene, because equilibrium climate sensitivity is identical for the two intervals when we account for such impacts using sea-level reconstructions. We conclude that, on a global scale, no unexpected climate feedbacks operated during the warm Pliocene, and that predictions of equilibrium climate sensitivity (excluding long-term ice-albedo feedbacks) for our Pliocene-like future (with CO2 levels up to maximum Pliocene levels of 450 parts per million) are well described by the currently accepted range of an increase of 1.5 K to 4.5 K per doubling of CO2.

The impacts of irrigation with transferred and saline reclaimed water in the soil biological quality of two citrus species: Adaptations to low water availability

NASA Astrophysics Data System (ADS)

Bastida, Felipe; Abadía, Joaquín; García, Carlos; Torres, Irene; Ruiz Navarro, Antonio; José Alarcón, Juan; Nicolás, Emilio

2017-04-01

Mediterranean agroecosystems are limited by the availability of water and hence it is fundamental to find new water sources for sustainable agriculture in the face of climate change. Here, the effects of irrigation with water from different sources were analyzed in the soil microbial community and plant status of grapefruit and mandarin trees in a Mediterranean agro-ecosystem located in south-east of Spain. Four irrigation treatments were evaluated: i) water with an average electrical conductivity (EC) of 1.1 dS m-1 from the "Tagus-Segura" water-transfer canal (TW); ii) reclaimed water (EC = 3.21 dS m-1) from a wastewater-treatment-plant (RW); iii) irrigation with TW, except in the second stage of fruit development, when RW was applied (TWc); and iv) irrigation with RW except in the second stage, when TW was used (RWc). Phospholipid fatty acids indicated that microbial biomass was greater under grapefruit than under mandarin. In the case of grapefruit, TW showed a lower bacterial biomass than RW, RWc, and TWc, while RW showed the lowest values in the mandarin soil. In grapefruit soil, β-glucosidase and cellobiohydrolase activities, related to C cycling, were greater in RW and TWc than in TW and RWc. In mandarin soil, the greatest activity of these enzymes was found in TWc. The saline stress induced lower net photosynthesis (A) and stomatal conductance (gs) in plants of RW, RWc and TWc in comparison with TW. The annual use of reclaimed water or the combined irrigation with TWc positively influenced the soil biological quality of a grapefruit agro-ecosystem. Conversely, the mandarin soil community was more sensitive to the annual irrigation with RW.

Equilibrium and Effective Climate Sensitivity

NASA Astrophysics Data System (ADS)

Rugenstein, M.; Bloch-Johnson, J.

2016-12-01

Atmosphere-ocean general circulation models, as well as the real world, take thousands of years to equilibrate to CO2 induced radiative perturbations. Equilibrium climate sensitivity - a fully equilibrated 2xCO2 perturbation - has been used for decades as a benchmark in model intercomparisons, as a test of our understanding of the climate system and paleo proxies, and to predict or project future climate change. Computational costs and limited time lead to the widespread practice of extrapolating equilibrium conditions from just a few decades of coupled simulations. The most common workaround is the "effective climate sensitivity" - defined through an extrapolation of a 150 year abrupt2xCO2 simulation, including the assumption of linear climate feedbacks. The definitions of effective and equilibrium climate sensitivity are often mixed up and used equivalently, and it is argued that "transient climate sensitivity" is the more relevant measure for predicting the next decades. We present an ongoing model intercomparison, the "LongRunMIP", to study century and millennia time scales of AOGCM equilibration and the linearity assumptions around feedback analysis. As a true ensemble of opportunity, there is no protocol and the only condition to participate is a coupled model simulation of any stabilizing scenario simulating more than 1000 years. Many of the submitted simulations took several years to conduct. As of July 2016 the contribution comprises 27 scenario simulations of 13 different models originating from 7 modeling centers, each between 1000 and 6000 years. To contribute, please contact the authors as soon as possible We present preliminary results, discussing differences between effective and equilibrium climate sensitivity, the usefulness of transient climate sensitivity, extrapolation methods, and the state of the coupled climate system close to equilibrium. Caption for the Figure below: Evolution of temperature anomaly and radiative imbalance of 22 simulations with 12 models (color indicates the model). 20 year moving average.

Self-Assembled Nanorod Structures on Nanofibers for Textile Electrochemical Capacitor Electrodes with Intrinsic Tactile Sensing Capabilities.

PubMed

Shi, HaoTian H; Khalili, Nazanin; Morrison, Taylor; Naguib, Hani E

2018-05-21

A novel polyaniline nanorod (PAniNR) three-dimensional structure was successfully grown on flexible polyacrylonitrile (PAN) nanofiber substrate as the electrode material for electrochemical capacitors (ECs), constructed via self-stabilized dispersion polymerization process. The electrode offered desired mechanical properties such as flexibility and bendability, whereas it maintained optimal electrochemical characteristics. The electrode and the assembled EC cell also achieved intrinsic piezoresistive sensing properties, leading to real-time monitoring of excess mechanical pressure and bending during cell operations. The PAniNR@PAN electrodes show an average diameter of 173.6 nm, with the PAniNR growth of 50.7 nm in length. Compared to the electrodes made from pristine PAni, the gravimetric capacitance increased by 39.8% to 629.6 F/g with aqueous acidic electrolyte. The electrode and the assembled EC cell with gel electrolyte were responsive to tensile, compressive, and bending stresses with a sensitivity of 0.95 MPa -1 .

Gait event detection using linear accelerometers or angular velocity transducers in able-bodied and spinal-cord injured individuals.

PubMed

Jasiewicz, Jan M; Allum, John H J; Middleton, James W; Barriskill, Andrew; Condie, Peter; Purcell, Brendan; Li, Raymond Che Tin

2006-12-01

We report on three different methods of gait event detection (toe-off and heel strike) using miniature linear accelerometers and angular velocity transducers in comparison to using standard pressure-sensitive foot switches. Detection was performed with normal and spinal-cord injured subjects. The detection of end contact (EC), normally toe-off, and initial contact (IC) normally, heel strike was based on either foot linear accelerations or foot sagittal angular velocity or shank sagittal angular velocity. The results showed that all three methods were as accurate as foot switches in estimating times of IC and EC for normal gait patterns. In spinal-cord injured subjects, shank angular velocity was significantly less accurate (p<0.02). We conclude that detection based on foot linear accelerations or foot angular velocity can correctly identify the timing of IC and EC events in both normal and spinal-cord injured subjects.

Production of BMP4 by endothelial cells is crucial for endogenous thymic regeneration

PubMed Central

Wertheimer, Tobias; Velardi, Enrico; Tsai, Jennifer; Cooper, Kirsten; Xiao, Shiyun; Kloss, Christopher C.; Ottmüller, Katja J.; Mokhtari, Zeinab; Brede, Christian; deRoos, Paul; Kinsella, Sinéad; Palikuqi, Brisa; Ginsberg, Michael; Young, Lauren F.; Kreines, Fabiana; Lieberman, Sophia R.; Lazrak, Amina; Guo, Peipei; Malard, Florent; Smith, Odette M.; Shono, Yusuke; Jenq, Robert R.; Hanash, Alan M.; Nolan, Daniel J.; Butler, Jason M.; Beilhack, Andreas; Manley, Nancy R.; Rafii, Shahin; Dudakov, Jarrod A; van den Brink, Marcel RM

2018-01-01

The thymus is extremely sensitive to damage but also has a remarkable ability to repair itself. However, the mechanisms underlying this endogenous regeneration remain poorly understood and this capacity diminishes considerably with age. Here we show that thymic endothelial cells (ECs) comprise a critical pathway of regeneration, via their production of BMP4. ECs increased their production of BMP4 after thymic damage, and abrogating BMP4 signalling or production by either pharmacologic or genetic inhibition impaired thymic repair. EC-derived BMP4 acted on thymic epithelial cells (TECs) to increase their expression of Foxn1, a key transcription factor involved in TEC development, maintenance and regeneration; and its downstream targets such as Dll4, itself a key mediator of thymocyte development and regeneration. These studies demonstrate the importance of the BMP4 pathway in endogenous tissue regeneration and offer a potential clinical approach to enhance T cell immunity. PMID:29330161

Electrochemical surface-enhanced Raman scattering measurement on ligand capped PbS quantum dots at gap of Au nanodimer

NASA Astrophysics Data System (ADS)

Li, Xiaowei; Minamimoto, Hiro; Murakoshi, Kei

2018-05-01

The vibrational characteristics of ligand-capped lead sulfide (PbS) quantum dots (QDs) were clarified via electrochemical surface-enhanced Raman spectroscopy (EC-SERS) using a hybridized system of gold (Au) nanodimers and PbS QDs under electrochemical potential control. Enhanced electromagnetic field caused by the coupling of QDs with plasmonic Au nanodimers allowed the characteristic behavior of the ligand oleic acid (OA) on the PbS QD surface to be detected under electrochemical potential control. Binding modes between the QDs and OA molecules were characterized using synchronous two-dimensional correlation spectra at distinct electrochemical potentials, confirming that the bidentate bridging mode was probably the most stable mode even under relatively negative potential polarization. Changes in binding modes and molecular orientations resulted in fluctuations in EC-SERS spectra. The present observations strongly recommend the validity of the QD-plasmonic nanostructure coupled system for sensitive molecular detection via EC-SERS.

Sensitivity of ground - water recharge estimates to climate variability and change, Columbia Plateau, Washington

USGS Publications Warehouse

Vaccaro, John J.

1992-01-01

The sensitivity of groundwater recharge estimates was investigated for the semiarid Ellensburg basin, located on the Columbia Plateau, Washington, to historic and projected climatic regimes. Recharge was estimated for predevelopment and current (1980s) land use conditions using a daily energy-soil-water balance model. A synthetic daily weather generator was used to simulate lengthy sequences with parameters estimated from subsets of the historical record that were unusually wet and unusually dry. Comparison of recharge estimates corresponding to relatively wet and dry periods showed that recharge for predevelopment land use varies considerably within the range of climatic conditions observed in the 87-year historical observation period. Recharge variations for present land use conditions were less sensitive to the same range of historical climatic conditions because of irrigation. The estimated recharge based on the 87-year historical climatology was compared with adjustments to the historical precipitation and temperature records for the same record to reflect CO2-doubling climates as projected by general circulation models (GCMs). Two GCM scenarios were considered: an average of conditions for three different GCMs with CO2 doubling, and a most severe “maximum” case. For the average GCM scenario, predevelopment recharge increased, and current recharge decreased. Also considered was the sensitivity of recharge to the variability of climate within the historical and adjusted historical records. Predevelopment and current recharge were less and more sensitive, respectively, to the climate variability for the average GCM scenario as compared to the variability within the historical record. For the maximum GCM scenario, recharge for both predevelopment and current land use decreased, and the sensitivity to the CO2-related climate change was larger than sensitivity to the variability in the historical and adjusted historical climate records.

The role of North Atlantic Ocean circulation and biological sequestration on atmospheric CO2 uptake during the last deglaciation (CL Division Outstanding ECS Award Lecture)

NASA Astrophysics Data System (ADS)

Muschitiello, Francesco; D'Andrea, William J.; Dokken, Trond M.; Schmittner, Andreas

2017-04-01

Understanding the impact of ocean circulation on the global atmospheric CO2 budget is of paramount importance for anticipating the consequences of projected future changes in Atlantic Meridional Overturning Circulation (AMOC). In particular, the efficiency of the oceanic biological pump can impact atmospheric CO2 through changes in vertical carbon export mediated by variations in the nutrient inventory of the North Atlantic basin. However, the causal relationship between North Atlantic Ocean circulation, biological carbon sequestration, and atmospheric CO2 is poorly understood. Here we present new high-resolution planktic-benthic 14C data and biomarker records from an exceptionally well-dated marine core from the Nordic Seas spanning the last deglaciation ( 15,000-10,000 years BP). The records document for the first time large and rapid atmospheric CO2 drawdowns and increase in plankton stocks during major North Atlantic cooling events. Using transient climate simulations from a fully coupled climate-biosphere model, we show that minor perturbations of the North Atlantic biological pump resulting from surface freshening and AMOC weakening can have a major impact on the global atmospheric CO2 budget. Furthermore, our data help clarifying the timing and magnitude of the deglacial CO2 signal recorded in Antarctic ice cores. We conclude that the global CO2 budget is more sensitive to perturbations in North Atlantic circulation than previously thought, which has significance in the future debate of the AMOC response to anthropogenic warming.

Assessment of the sensitizing potency of preservatives with chance of skin contact by the loose-fit coculture-based sensitization assay (LCSA).

PubMed

Sonnenburg, Anna; Schreiner, Maximilian; Stahlmann, Ralf

2015-12-01

Parabens, methylisothiazolinone (MI) and its derivative methylchloroisothiazolinone (MCI), are commonly used as preservatives in personal care products. They can cause hypersensitivity reactions of the human skin. We have tested a set of nine parabens, MI alone and in combination with MCI in the loose-fit coculture-based sensitization assay (LCSA). The coculture of primary human keratinocytes and allogenic dendritic cell-related cells (DC-rc) in this assay emulates the in vivo situation of the human skin. Sensitization potency of the test substances was assessed by flow cytometric analysis of the DC-rc maturation marker CD86. Determination of the concentration required to cause a half-maximal increase in CD86-expression (EC50sens) allowed a quantitative evaluation. The cytotoxicity of test substances as indicator for irritative potency was measured by 7-AAD (7-amino-actinomycin D) staining. Parabens exhibited weak (methyl-, ethyl-, propyl- and isopropylparaben) or strong (butyl-, isobutyl-, pentyl- and benzylparaben) effects, whereas phenylparaben was found to be a moderate sensitizer. Sensitization potencies of parabens correlated with side chain length. Due to a pronounced cytotoxicity, we could not estimate an EC50sens value for MI, whereas MI/MCI was classified as sensitizer and also showed cytotoxic effects. Parabens showed no (methyl- and ethylparaben) or weak irritative potencies (propyl-, isopropyl-, butyl-, isobutyl-, phenyl- and benzylparaben), only pentylparaben was rated to be irritative. Overall, we were able to demonstrate and compare the sensitizing potencies of parabens in this in vitro test. Furthermore, we showed an irritative potency for most of the preservatives. The data further support the usefulness of the LCSA for comparison of the sensitizing potencies of xenobiotics.

Climatic record of the Iberian peninsula from lake Moncortes' sediments

NASA Astrophysics Data System (ADS)

Cao, Min; Huguet, Carme; Rull, Valenti; Valero, Blas; Rosell-Mele, Antoni

2014-05-01

Climatic record of the Iberian peninsula from lake Moncortes' sediments Min Cao1, Carme Huguet1, Valenti Rull2, Blas L. Valero-Garces3, Antoni Rosell-Melé1,4 1Institut de Ciència i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Catalonia, Spain; 2Institut de Botanic de Barcelona (CSIC), Passeig del Migdia s/n, 08038, Barcelona, Spain, 3 Instituto Pirenaico de Ecologıa (CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain, 4Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Catalonia, Spain. The continuing buildup of industrial greenhouse gases in the atmosphere and concomitant increase in global temperatures has made much of the world's society aware that decades to centuries of environmental change lie ahead, and that these will have profound economic, political and societal impacts. The Iberian Peninsula lies in the boundary between tropical and subtropical climates and seems to amplify the climatic signals form the northern hemisphere through both atmospheric and water circulation feedbacks, making it an ideal site to monitor Northern hemisphere climate changes. This extreme sensitivity to climatic changes also makes the Iberian Peninsula extremely vulnerable to future climate changes. This is why understanding sensitivity to climate change and the consequences it will have on both climate and the hydrological cycle is key to implement preventive measures. The aim of our study is to come up with a high resolution quantitative reconstruction of climate variability (temperature, production and precipitation) in the Iberian Peninsula from lake sediments. We also want to establish the relation between those changes and the ones observed in both ice cores from Greenland and paleotemperature records from marine sediments of the continental Iberian margin. For these reasons we sampled a core in Moncortes (42.3N, 0.99E), a lake of karstic origin with an average depth of 25m and an area of 0.19km2. Lake Moncortes is situated at 1065 m above sea level, has an average temperature of 10ºC (minimum 3 and maximum 16ºC) and a mean annual precipitation of 770mm. We used the MBT/CBT (Weijers et al. 2007) proxy of pH and terrestrial temperature and the TEX86 temperature proxy (Schouten et al. 2002) to estimate changes in and around the lake. Both proxies are based on the glycerol dialkyl glycerol tetraethers (GDGTs) of archaea (isoprenoid GDGTs) and bacteria (branched GDGTs) origin. We also measured soils surrounding the lake (Menges et al. 2013) in order to establish end-members for the proxies as well as organic matter transport. Data on n-alkane isotopes will help establish hydrographic regime changes. We observe changes in temperature and humidity consistent with those on teh northern hemisphere. J. Menges, C. Huguet, J.M. Alcañiz, S. Fietz, D. Sachse, A. Rosell-Melé Biogechemistry discussions (2013), BGD bg-2013-198. S. Schouten, E.C. Hopmans, E. Schefuss, J.S.S. Damste, Earth and Planetary Science Letters 204(2002) 265-274 J.W.H. Weijers, S. Schouten, J.S.S. Damste, Geochimica Et Cosmochimica Acta 71(2007) A1098-A1098.

Drought sensitivity changes over the last century at the North American savanna-forest boundary

NASA Astrophysics Data System (ADS)

Heilman, K.; McLachlan, J. S.

2017-12-01

Future environmental changes can affect the sensitivity of tree growth to climate. Theses changes are of particular concern at biome boundaries where tree distribution could shift as a result of changes in both drought and drought sensitivity. One such region is the North American savanna-forest boundary, where increased CO2 and droughts could alter savanna and forest ecosystem distributions in two contrasting ways: 1). More severe droughts may increase drought sensitivity, favoring open savanna ecosystems or, 2). Increases in water use efficiency resulting from higher atmospheric CO2 may decrease drought sensitivity, promoting forest expansion. This study sought to understand whether the past 100 years of climate and CO2 changes have impacted regional tree growth-climate sensitivity. To test for these climate sensitivity changes, we measured the sensitivity of Quercus spp. radial growth to Palmer Drought Severity Index (PDSI). Tree growth sensitivity to climate can vary according to many factors, including: stand structure, available moisture, and tree age. To control for these factors, we sampled tree growth-climate responses at sites in both open and closed forests, and at both low and high annual precipitation. Within each site, we compared growth responses to climate between trees established under high CO2 conditions after 1950 (high CO2 young), and tree established before 1950 under low CO2 levels (low CO2 young). At most sites, low CO2 young have a higher drought sensitivity than higher CO2 young. These changes in the sensitivity to drought are consistent with CO2 enhancement of water use efficiency. Furthermore, these differences in drought sensitivity are higher at sites with high temperature and low precipitation, suggesting that the alleviation of drought is more likely in hot and dry regions. Thus, if CO2 enhancement is indeed occurring in these systems, lower growth sensitivity to drought in hot and dry regions could favor increased forest growth. If changes in drought sensitivity scale to ecosystem level, decreased drought sensitivity may have helped promote regional forest expansion.

Aerosol Radiative Forcing Estimates from South Asian Clay Brick Production Based on Direct Emission Measurements

NASA Astrophysics Data System (ADS)

Weyant, C.; Athalye, V.; Ragavan, S.; Rajarathnam, U.; Kr, B.; Lalchandani, D.; Maithel, S.; Malhotra, G.; Bhanware, P.; Thoa, V.; Phuong, N.; Baum, E.; Bond, T. C.

2012-12-01

About 150-200 billion clay bricks are produced in India every year. Most of these bricks are fired in small-scale traditional kilns that burn coal or biomass without pollution controls. Reddy and Venkataraman (2001) estimated that 8% of fossil fuel related PM2.5 emissions and 23% of black carbon emissions in India are released from brick production. Few direct emissions measurements have been done in this industry and black carbon emissions, in particular, have not been previously measured. In this study, 9 kilns representing five common brick kiln technologies were tested for aerosol properties and gaseous pollutant emissions, including optical scattering and absorption and thermal-optical OC/EC. Simple relationships are then used to estimate the radiative-forcing impact. Kiln design and fuel quality greatly affect the overall emission profiles and relative climate warming. Batch production kilns, such as the Downdraft kiln, produce the most PM2.5 (0.97 gPM2.5/fired brick) with an OC/EC fraction of 0.3. Vertical Shaft Brick kilns using internally mixed fuels produce the least PM (0.09 gPM2.5/kg fired brick) with the least EC (OC/EC = 16.5), but these kilns are expensive to implement and their use throughout Southern Asia is minimal. The most popular kiln in India, the Bull's Trench kiln, had fewer emissions per brick than the Downdraft kiln, but an even higher EC fraction (OC/EC = 0.05). The Zig-zag kiln is similar in structure to the Bull's Trench kiln, but the emission factors are significantly lower: 50% reduction for CO, 17% for PM2.5 and 60% for black carbon. This difference in emissions suggests that converting traditional Bull's Trench kilns into less polluting Zig-zag kilns would result in reduced atmospheric warming from brick production.

[Spatial heterogeneity of soil salinization and its influencing factors in the typical region of the Mu Us Desert-Loess Plateau transitional zone, Northwest China].

PubMed

Zhao, Xuan; Hao, Qi Li; Sun, Ying Ying

2017-06-18

Studies on the spatial heterogeneity of saline soil in the Mu Us Desert-Loess Plateau transition zone are meaningful for understanding the mechanisms of land desertification. Taking the Mu Us Desert-Loess Plateau transition zone as the study subject, its spatial heterogeneity of pH, electrical conductivity (EC) and total salt content were analyzed by using on-site sampling followed with indoor analysis, classical statistical and geostatistical analysis. The results indicated that: 1) The average values of pH, EC and total salt content were 8.44, 5.13 mS·cm -1 and 21.66 g·kg -1 , respectively, and the coefficient of variation ranged from 6.9% to 73.3%. The pH was weakly variable, while EC and total salt content were moderately variable. 2) Results of semivariogram analysis showed that the most fitting model for spatial variability of all three indexes was spherical model. The C 0 /(C 0 +C) ratios of three indexes ranged from 8.6% to 14.3%, which suggested the spatial variability of all indexes had a strong spatial autocorrelation, and the structural factors played a more important role. The variation range decreased in order of pH

Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Niu, Hewen; Kang, Shichang; Wang, Hailong; Zhang, Rudong; Lu, Xixi; Qian, Yun; Paudyal, Rukumesh; Wang, Shijin; Shi, Xiaofei; Yan, Xingguo

2018-05-01

Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32 µg m-3, respectively. Although the annual mean OC / EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a. s. l. ) of Mt. Yulong. Strong photochemical reactions and local tourism activities were likely the main factors inducing high OC / EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m2 g-1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol-climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 %) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.

Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, Hewen; Kang, Shichang; Wang, Hailong

Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32μg m -3, respectively. Although the annual mean OC/EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a.s.l.) of Mt. Yulong. Strong photochemical reactions and local tourism activitiesmore » were likely the main factors inducing high OC/EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m 2g -1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol–climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50%) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.« less

Relation of an Echocardiographic-Based Cardiac Calcium Score to Mitral Stenosis Severity and Coronary Artery Disease in Patients with Severe Aortic Stenosis.

PubMed

Sheng, Siyuan P; Howell, Lucius A; Caughey, Melissa C; Yeung, Michael; Vavalle, John P

2018-01-15

Patients with calcific aortic stenosis (AS) often have diffuse cardiac calcification involving the mitral valve apparatus and coronary arteries. We examined the association between global cardiac calcification quantified by a previously validated echocardiographic calcium score (eCS) with the severity of mitral stenosis (MS) and coronary artery disease (CAD) in patients with a clinical diagnosis of severe calcific AS. In this sample of 147 patients (mean age 81 ± 9 years, 50% male), 81 patients (55%) were determined by echocardiography to have some degree of MS. Higher mean eCS was observed in patients with more severe MS (r = 0.54, p < 0.0001). Higher eCS was also inversely associated with mitral valve area (r = -0.31, p = 0.001) and positively associated with mitral valve mean pressure gradient (r = 0.46, p < 0.0001) and mitral valve peak flow velocity (r = 0.55, p < 0.0001). The area under the receiver operating characteristic curve for using eCS to predict the presence of MS was 0.76. An eCS ≥ 8 predicted MS with a sensitivity of 68%, specificity of 76%, positive predictive value of 77%, and negative predictive value of 66%. High eCS, relative to low eCS, was associated with 2.70 times the adjusted odds of CAD (odds ratio = 2.70, 95% confidence interval 1.02 to 7.17). In conclusion, global cardiac calcification is associated with MS and CAD in patients with severe calcific AS, and eCS shows ability to predict the presence of MS. This study suggests that a simple eCS may be used as part of a risk-stratification tool in patients with severe calcific aortic valve stenosis. Copyright © 2017 Elsevier Inc. All rights reserved.

"I don't know what I would have done." Women's experiences acquiring ulipristal acetate emergency contraception online from 2011 to 2015.

PubMed

Smith, Nicole K; Cleland, Kelly; Wagner, Brandon; Trussell, James

2017-04-01

This study describes women's reasons for seeking ulipristal acetate (UPA) for emergency contraception (EC) through the only authorized online retailer for UPA EC in the US. Women aged 14 to 59 years, living in states that allow prescription medications to be shipped from out-of-state, accessed the KwikMed online pharmacy between January 2011 and December 2015. After completing a medical eligibility screener, women answered optional multiple-choice questions. To obtain UPA through KwikMed, individuals must be female, 50 years of age or younger, not currently pregnant or breastfeeding and not attempting to order UPA more than once within 30 days or more than four times per year. Over the 5-year period, KwikMed provided 8019 prescriptions for UPA, and the number of women using this service more than tripled over time. Among women who responded to the survey questions (n=7133; response rate = 89%), most sought EC because of a condom failure (45.3%) or because they did not use regular contraception (41.2%). More than half (53.5%) of women reported that they chose UPA because of its effectiveness compared to levonorgestrel EC pills, and 58.9% preferred ordering UPA online because they found it easier than getting it from a doctor, clinic or pharmacy. This study documents the importance of providing confidential services for acquiring EC online. Benefits of online access include convenience, less embarrassment, avoiding situations in which a provider might refuse to provide EC because of their own ideological belief and more reliable availability for this time-sensitive contraceptive. Though physical, logistical and societal barriers can restrict women's access to EC, this study demonstrates that providing access to UPA online empowers women to obtain EC when they need it. Copyright © 2016 Elsevier Inc. All rights reserved.

Light-intensity grazing improves alpine meadow productivity and adaption to climate change on the Tibetan Plateau

PubMed Central

Zhang, Tao; Zhang, Yangjian; Xu, Mingjie; Zhu, Juntao; Wimberly, Michael C.; Yu, Guirui; Niu, Shuli; Xi, Yi; Zhang, Xianzhou; Wang, Jingsheng

2015-01-01

To explore grazing effects on carbon fluxes in alpine meadow ecosystems, we used a paired eddy-covariance (EC) system to measure carbon fluxes in adjacent fenced (FM) and grazed (GM) meadows on the Tibetan plateau. Gross primary productivity (GPP) and ecosystem respiration (Re) were greater at GM than FM for the first two years of fencing. In the third year, the productivity at FM increased to a level similar to the GM site. The higher productivity at GM was mainly caused by its higher photosynthetic capacity. Grazing exclusion did not increase carbon sequestration capacity for this alpine grassland system. The higher optimal photosynthetic temperature and the weakened ecosystem response to climatic factors at GM may help to facilitate the adaption of alpine meadow ecosystems to changing climate. PMID:26515954

WRF-Cordex simulations for Europe: mean and extreme precipitation for present and future climates

NASA Astrophysics Data System (ADS)

Cardoso, Rita M.; Soares, Pedro M. M.; Miranda, Pedro M. A.

2013-04-01

The Weather Research and Forecast (WRF-ARW) model, version 3.3.1, was used to perform the European domain Cordex simulations, at 50km resolution. A first simulation, forced by ERA-Interim (1989-2009), was carried out to evaluate the models performance to represent the mean and extreme precipitation in present European climate. This evaluation is based in the comparison of WRF results against the ECAD regular gridded dataset of daily precipitation. Results are comparable to recent studies with other models for the European region, at this resolution. For the same domain a control and a future scenario (RCP8.5) simulation was performed to assess the climate change impact on the mean and extreme precipitation. These regional simulations were forced by EC-EARTH model results, and, encompass the periods from 1960-2006 and 2006-2100, respectively.

Sensitivity of Ocean Chemistry and Oxygen Change to the Uncertainty in Climate Change

NASA Astrophysics Data System (ADS)

Cao, L.; Wang, S.; Zheng, M.; Zhang, H.

2014-12-01

With increasing atmospheric CO2 and climate change, global ocean is undergoing substantial physical and biogeochemical changes. In particular, changes in ocean oxygen and carbonate chemistry have great implication for marine biota. There is considerable uncertainty in the projections of future climate change, and it is unclear how the uncertainty in climate change would affect the projection of ocean oxygen and carbonate chemistry. To examine the effect of climate change on ocean oxygen and carbonate chemistry, we used an Earth system model of intermediate complexity to perform simulations that are driven by atmospheric CO2 concentration pathway of RCP 8.5 with climate sensitivity varying from 0.0°C to 4.5 °C. Climate change affects carbonate chemistry and oxygen mainly through its impact on ocean temperature, ocean ventilation, and concentration of dissolved inorganic carbon and alkalinity. Our simulations show that climate change mitigates the decrease of carbonate ions at the ocean surface but has negligible effect on surface ocean pH. Averaged over the whole ocean, climate change acts to decrease oxygen concentration but mitigates the CO2-induced reduction of carbonate ion and pH. In our simulations, by year 2500, every degree increase of climate sensitivity warms the ocean by 0.8 °C and reduces ocean-mean dissolved oxygen concentration by 5.0%. Meanwhile, every degree increase of climate sensitivity buffers CO2-induced reduction in ocean-mean carbonate ion concentration and pH by 3.4% and 0.02 units, respectively. Our study demonstrates different sensitivities of ocean temperature, carbonate chemistry, and oxygen, in terms of both the sign and magnitude, to the amount of climate change, which have great implications for understanding the response of ocean biota to climate change.

Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples.

PubMed

Tallarico, Lenita de Freitas; Borrely, Sueli Ivone; Hamada, Natália; Grazeffe, Vanessa Siqueira; Ohlweiler, Fernanda Pires; Okazaki, Kayo; Granatelli, Amanda Tosatte; Pereira, Ivana Wuo; Pereira, Carlos Alberto de Bragança; Nakano, Eliana

2014-12-01

A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies. Copyright © 2014 Elsevier Inc. All rights reserved.

Reconstruction of Last Glacial Tropical SST Anomalies from Mg/Ca and UK37' to Constrain Climate Sensitivity

NASA Astrophysics Data System (ADS)

Lea, D. W.; de Garidel-Thoron, T.; Bard, E. G.; Kienast, M.

2016-12-01

Proxy paleoclimate data provides an important constrain on climate sensitivity. The tropics have been identified as a region which primarily responds to greenhouse gas forcing (GHF). The SENSETROP (Sensitivity of the Tropics) group has identified the LGM, HS1 and HS2 as key time windows to test the hypothesis that SST anomalies recorded by two geochemical paleothermometers, Mg/Ca and UK37', can be used to establish tropical climate response and, via the magnitude and spatial pattern of these anomalies, provide robust comparisons to the output of general circulation models. This work is a logical extension of prior efforts such as CLIMAP and MARGO, which largely relied on faunal SST proxies that are affected by other factors such as productivity or water column structure. With this goal in mind we have developed the SENSETROP database of published and unpublished Mg/Ca and UK37' data from low latitude (30° N to 30° S) marine cores spanning the last glacial cycle. The database contains 78 Mg/Ca records and 40 UK37' records, distributed between the tropical ocean basins: 49 in the Pacific Ocean, 32 in the Indian Ocean, and 27 in the Atlantic Ocean. Most of the cores are confined to the ocean margins. All of the data come from well dated records that include radiocarbon. As a test of the database, we determined the average SST anomaly during the LGM, 19,000-23,000 yr BP, relative to the late Holocene, 0-4,000 yr BP, from select records that contain at least 4 SST points in each time window for which the SDs < 0.75 °C. For G. ruber (all morphotypes) Mg/Ca, the recorded anomaly from 23 cores is -2.6 ± 0.6 °C, based on >1100 individual determinations. For UK37', the recorded anomaly for 14 cores is -2.4 ± 0.9 °C, based on >400 individual determinations. Agreement between these two independent proxies increases confidence in the LGM cooling level. The new results from the SENSETROP database show a strong level of homogeneity throughout the tropics, with slightly ( 0.3 °C) greater cooling in the NH. These results are in marked contrast to MARGO, which showed a strong level of heterogeneity in tropical SST. The new SENSETROP results are consistent with a primary control of greenhouse gas forcing on tropical SSTs during the LGM. Extension of these results to ECS determinations suggests values consistent with the IPCC canonical range.

Vulnerability of the global terrestrial ecosystems to climate change.

PubMed

Li, Delong; Wu, Shuyao; Liu, Laibao; Zhang, Yatong; Li, Shuangcheng

2018-05-27

Climate change has far-reaching impacts on ecosystems. Recent attempts to quantify such impacts focus on measuring exposure to climate change but largely ignore ecosystem resistance and resilience, which may also affect the vulnerability outcomes. In this study, the relative vulnerability of global terrestrial ecosystems to short-term climate variability was assessed by simultaneously integrating exposure, sensitivity, and resilience at a high spatial resolution (0.05°). The results show that vulnerable areas are currently distributed primarily in plains. Responses to climate change vary among ecosystems and deserts and xeric shrublands are the most vulnerable biomes. Global vulnerability patterns are determined largely by exposure, while ecosystem sensitivity and resilience may exacerbate or alleviate external climate pressures at local scales; there is a highly significant negative correlation between exposure and sensitivity. Globally, 61.31% of the terrestrial vegetated area is capable of mitigating climate change impacts and those areas are concentrated in polar regions, boreal forests, tropical rainforests, and intact forests. Under current sensitivity and resilience conditions, vulnerable areas are projected to develop in high Northern Hemisphere latitudes in the future. The results suggest that integrating all three aspects of vulnerability (exposure, sensitivity, and resilience) may offer more comprehensive and spatially explicit adaptation strategies to reduce the impacts of climate change on terrestrial ecosystems. © 2018 John Wiley & Sons Ltd.

Different parts, different stories: climate sensitivity of growth is stronger in root collars vs. stems in tundra shrubs.

PubMed

Ropars, Pascale; Angers-Blondin, Sandra; Gagnon, Marianne; Myers-Smith, Isla H; Lévesque, Esther; Boudreau, Stéphane

2017-08-01

Shrub densification has been widely reported across the circumpolar arctic and subarctic biomes in recent years. Long-term analyses based on dendrochronological techniques applied to shrubs have linked this phenomenon to climate change. However, the multi-stemmed structure of shrubs makes them difficult to sample and therefore leads to non-uniform sampling protocols among shrub ecologists, who will favor either root collars or stems to conduct dendrochronological analyses. Through a comparative study of the use of root collars and stems of Betula glandulosa, a common North American shrub species, we evaluated the relative sensitivity of each plant part to climate variables and assessed whether this sensitivity is consistent across three different types of environments in northwestern Québec, Canada (terrace, hilltop and snowbed). We found that root collars had greater sensitivity to climate than stems and that these differences were maintained across the three types of environments. Growth at the root collar was best explained by spring precipitation and summer temperature, whereas stem growth showed weak and inconsistent responses to climate variables. Moreover, sensitivity to climate was not consistent among plant parts, as individuals having climate-sensitive root collars did not tend to have climate-sensitive stems. These differences in sensitivity of shrub parts to climate highlight the complexity of resource allocation in multi-stemmed plants. Whereas stem initiation and growth are driven by microenvironmental variables such as light availability and competition, root collars integrate the growth of all plant parts instead, rendering them less affected by mechanisms such as competition and more responsive to signals of global change. Although further investigations are required to determine the degree to which these findings are generalizable across the tundra biome, our results indicate that consistency and caution in the choice of plant parts are a key consideration for the success of future dendroclimatological studies on shrubs. © 2017 John Wiley & Sons Ltd.

Sensitivity of water resources in the Delaware River basin to climate variability and change

USGS Publications Warehouse

Ayers, Mark A.; Wolock, David M.; McCabe, Gregory J.; Hay, Lauren E.; Tasker, Gary D.

1994-01-01

Because of the greenhouse effect, projected increases in atmospheric carbon dioxide levels might cause global warming, which in turn could result in changes in precipitation patterns and evapotranspiration and in increases in sea level. This report describes the greenhouse effect; discusses the problems and uncertainties associated with the detection, prediction, and effects of climate change; and presents the results of sensitivity analyses of how climate change might affect water resources in the Delaware River basin. Sensitivity analyses suggest that potentially serious shortfalls of certain water resources in the basin could result if some scenarios for climate change come true . The results of model simulations of the basin streamflow demonstrate the difficulty in distinguishing the effects that climate change versus natural climate variability have on streamflow and water supply . The future direction of basin changes in most water resources, furthermore, cannot be precisely determined because of uncertainty in current projections of regional temperature and precipitation . This large uncertainty indicates that, for resource planning, information defining the sensitivities of water resources to a range of climate change is most relevant . The sensitivity analyses could be useful in developing contingency plans for evaluating and responding to changes, should they occur.

Strong carbon sink of monsoon tropical seasonal forest in Southern Vietnam

NASA Astrophysics Data System (ADS)

Deshcherevskaya, Olga; Anichkin, Alexandr; Avilov, Vitaly; Duy Dinh, Ba; Luu Do, Phong; Huan Tran, Cong; Kurbatova, Julia

2014-05-01

Comparison between anthropogenic emission of carbon dioxide and atmospheric carbon pool change displays that only half of emitted CO2 remains in air, leaving so-called 'missing sink' of carbon. Terrestrial biosphere and ocean accumulate each about a half of this value (Gifford, 1994). Forest biomes play the decisive role in 'missing sink' because of high primary production flux and large carbon pool. Almost all the sink belongs to boreal forests, because warming and wetting coupled with increasing CO2 concentration and N deposition gives more favorable conditions for boreal ecosystems. On the contrary, tropical climate changes effect on forests is not obvious, probably cause more drought conditions; tropical forests suffer from 1.2 % per year area reduction and disturbance. Whether primary tropical forests act as carbon sink is still unclear. Biomass inventories at 146 forest plots across all the tropics in 1987-1997 revealed low carbon sink in humid forests biomass of 49 (29-66; 95% C.I.) g C m-2 year-1 on average (Malhi, 2010). Estimates for undisturbed African forests are close to global (Ciais et al., 2008). Eddy covariance (EC) observations with weak-turbulence correction in Amazonia reveal near-zero or small negative (i.e. sink) balance (Clark, 2004). Three EC sites in SE Asia primary forests give near-zero balance again (Saigusa et al., 2008; Kosugi et al., 2012). There are two main groups of explanations of moderate tropical carbon sink: (a) recovering of large-disturbance in the past or (b) response to current atmospheric changes: increase of CO2 concentration and/or climate change. So, strong carbon accumulation is not common for primary tropical forests. In this context sink of 402 g C m-2 in 2012 at EC station of Nam Cat Tien (NCT), Southern Vietnam (N 11°27', E 107°24', 134 m a.s.l.) in primary monsoon tropical forest looks questionably. EC instrument set at NCT consists of CSAT3 sonic anemometer and LI-7500A open-path gas analyzer. All the standard EC procedures were applied to the raw 10-Hz data, including time-lag compensation, block average, WPL-correction, planar fit, low- and high-frequency corrections etc. in EddyPro software (LI-COR Inc., USA). Calculated fluxes with bad quality flags (more than 6 of 9) were excluded. Spikes due to rains, instrument malfunction were removed too. Storage of CO2 from the surface to the measurement level which is very significant in tall tropical forest was added to the flux. Then low-turbulence correction was applied with u*-threshold of 0.178 m s-1. After these steps only 43 % of 30-min data of 2012 still presented, so the rate of gaps was 57 % (mainly at night and in rains). Data were gapfilled using on-line tool at the web-site of Max-Plank Institute, Germany and Flux-Analysis Tool, Japan. Different gap-filling procedures (non-linear regressions, look-up tables, model evaluation, artificial gaps-method) as well as u*-threshold shifting from 0 to 0.25 resulted in drift of 2012 net carbon exchange total from -296 to -612 g C m-2 (strong carbon sink still remain). Unfortunately, the situation of more then 50 % of gaps in CO2 flux is usual for tropical EC stations because of frequent calm nights. So, a gap-filling algorithm is extremely important for evaluation of long-term totals. We found for Vietnamese data that even few spikes which were not removed before gap-filling can change all-year total by up to 20-50 g m-2 year-1. Especially 'powerful' are big positive values at night in rare-occurred good turbulence. Possibly these values are physical. But they influence regressions in look-up table method dramatically because amount of data in peak of rainy season in night-time is too small. So, the gap-filling algorithm happened to be very sensitive to spikes. Additionally, striking was the fact that storage of CO2 appeared to be the main factor influencing 1-year totals after gap-filling procedure. Taking storage into account shifted the 2012 sum from +182 to -402 g m-2 year-1, from carbon source to the strong sink. Storage total for all the year was near-zero, but in our case including of storage resulted in gap-filling regression changes with corresponding change in total carbon balance. Probably the only way for proper net carbon balance evaluation for NCT site is chamber-measurements of night respiration of different ecosystem components, as used at Pasoh EC station, Malaysia. Ciais P., Piao S.L., Cadule P., Friedlingstein P., & Chedin A. Variability and recent trends in the African carbon balance. Biogeosciences Discussions, 5(4), 2008. Pp. 3497-3532. Clark D.A. Sources or sinks? The responses of tropical forests to current and future climate and atmospheric composition. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 359(1443), 2004. Pp. 477-491. Gifford, R. M. (1994). The global carbon cycle: a viewpoint on the missing sink. Functional Plant Biology, 21(1), 1-15. Kosugi Y., Takanashi S., Tani M., Ohkubo S., Matsuo N., Itoh M., Noguchi S. & Nik A.R. Effect of inter-annual climate variability on evapotranspiration and canopy CO2 exchange of a tropical rainforest in Peninsular Malaysia. Journal of forest research, 17(3), 2012. Pp. 227-240. Malhi, Y. (2010). The carbon balance of tropical forest regions, 1990-2005. Current Opinion in Environmental Sustainability, 2(4), 237-244. Saigusa, N., Yamamoto, S., Hirata, R., Ohtani, Y., Ide, R., Asanuma, J., ... & Wang, H. (2008). Temporal and spatial variations in the seasonal patterns of CO2 flux in boreal, temperate, and tropical forests in East Asia. Agricultural and forest meteorology, 148(5), 700-713.

Palaeoclimatic insights into future climate challenges.

PubMed

Alley, Richard B

2003-09-15

Palaeoclimatic data document a sensitive climate system subject to large and perhaps difficult-to-predict abrupt changes. These data suggest that neither the sensitivity nor the variability of the climate are fully captured in some climate-change projections, such as the Intergovernmental Panel on Climate Change (IPCC) Summary for Policymakers. Because larger, faster and less-expected climate changes can cause more problems for economies and ecosystems, the palaeoclimatic data suggest the hypothesis that the future may be more challenging than anticipated in ongoing policy making. Large changes have occurred repeatedly with little net forcing. Increasing carbon dioxide concentration appears to have globalized deglacial warming, with climate sensitivity near the upper end of values from general circulation models (GCMs) used to project human-enhanced greenhouse warming; data from the warm Cretaceous period suggest a similarly high climate sensitivity to CO(2). Abrupt climate changes of the most recent glacial-interglacial cycle occurred during warm as well as cold times, linked especially to changing North Atlantic freshwater fluxes. GCMs typically project greenhouse-gas-induced North Atlantic freshening and circulation changes with notable but not extreme consequences; however, such models often underestimate the magnitude, speed or extent of past changes. Targeted research to assess model uncertainties would help to test these hypotheses.

Database search of spontaneous reports and pharmacological investigations on the sulfonylureas and glinides-induced atrophy in skeletal muscle

PubMed Central

Mele, Antonietta; Calzolaro, Sara; Cannone, Gianluigi; Cetrone, Michela; Conte, Diana; Tricarico, Domenico

2014-01-01

The ATP-sensitive K+ (KATP) channel is an emerging pathway in the skeletal muscle atrophy which is a comorbidity condition in diabetes. The “in vitro” effects of the sulfonylureas and glinides were evaluated on the protein content/muscle weight, fibers viability, mitochondrial succinic dehydrogenases (SDH) activity, and channel currents in oxidative soleus (SOL), glycolitic/oxidative flexor digitorum brevis (FDB), and glycolitic extensor digitorum longus (EDL) muscle fibers of mice using biochemical and cell-counting Kit-8 assay, image analysis, and patch-clamp techniques. The sulfonylureas were: tolbutamide, glibenclamide, and glimepiride; the glinides were: repaglinide and nateglinide. Food and Drug Administration-Adverse Effects Reporting System (FDA-AERS) database searching of atrophy-related signals associated with the use of these drugs in humans has been performed. The drugs after 24 h of incubation time reduced the protein content/muscle weight and fibers viability more effectively in FDB and SOL than in the EDL. The order of efficacy of the drugs in reducing the protein content in FDB was: repaglinide (EC50 = 5.21 × 10−6) ≥ glibenclamide(EC50 = 8.84 × 10−6) > glimepiride(EC50 = 2.93 × 10−5) > tolbutamide(EC50 = 1.07 × 10−4) > nateglinide(EC50 = 1.61 × 10−4) and it was: repaglinide(7.15 × 10−5) ≥ glibenclamide(EC50 = 9.10 × 10−5) > nateglinide(EC50 = 1.80 × 10−4) ≥ tolbutamide(EC50 = 2.19 × 10−4) > glimepiride(EC50=–) in SOL. The drug-induced atrophy can be explained by the KATP channel block and by the enhancement of the mitochondrial SDH activity. In an 8-month period, muscle atrophy was found in 0.27% of the glibenclamide reports in humans and in 0.022% of the other not sulfonylureas and glinides drugs. No reports of atrophy were found for the other sulfonylureas and glinides in the FDA-AERS. Glibenclamide induces atrophy in animal experiments and in human patients. Glimepiride shows less potential for inducing atrophy. PMID:25505577

Combgap Promotes Ovarian Niche Development and Chromatin Association of EcR-Binding Regions in BR-C.

PubMed

Hitrik, Anna; Popliker, Malka; Gancz, Dana; Mukamel, Zohar; Lifshitz, Aviezer; Schwartzman, Omer; Tanay, Amos; Gilboa, Lilach

2016-11-01

The development of niches for tissue-specific stem cells is an important aspect of stem cell biology. Determination of niche size and niche numbers during organogenesis involves precise control of gene expression. How this is achieved in the context of a complex chromatin landscape is largely unknown. Here we show that the nuclear protein Combgap (Cg) supports correct ovarian niche formation in Drosophila by controlling ecdysone-Receptor (EcR)- mediated transcription and long-range chromatin contacts in the broad locus (BR-C). Both cg and BR-C promote ovarian growth and the development of niches for germ line stem cells. BR-C levels were lower when Combgap was either reduced or over-expressed, indicating an intricate regulation of the BR-C locus by Combgap. Polytene chromosome stains showed that Cg co-localizes with EcR, the major regulator of BR-C, at the BR-C locus and that EcR binding to chromatin was sensitive to changes in Cg levels. Proximity ligation assay indicated that the two proteins could reside in the same complex. Finally, chromatin conformation analysis revealed that EcR-bound regions within BR-C, which span ~30 KBs, contacted each other. Significantly, these contacts were stabilized in an ecdysone- and Combgap-dependent manner. Together, these results highlight Combgap as a novel regulator of chromatin structure that promotes transcription of ecdysone target genes and ovarian niche formation.

Combgap Promotes Ovarian Niche Development and Chromatin Association of EcR-Binding Regions in BR-C

PubMed Central

Gancz, Dana; Lifshitz, Aviezer; Tanay, Amos

2016-01-01

The development of niches for tissue-specific stem cells is an important aspect of stem cell biology. Determination of niche size and niche numbers during organogenesis involves precise control of gene expression. How this is achieved in the context of a complex chromatin landscape is largely unknown. Here we show that the nuclear protein Combgap (Cg) supports correct ovarian niche formation in Drosophila by controlling ecdysone-Receptor (EcR)- mediated transcription and long-range chromatin contacts in the broad locus (BR-C). Both cg and BR-C promote ovarian growth and the development of niches for germ line stem cells. BR-C levels were lower when Combgap was either reduced or over-expressed, indicating an intricate regulation of the BR-C locus by Combgap. Polytene chromosome stains showed that Cg co-localizes with EcR, the major regulator of BR-C, at the BR-C locus and that EcR binding to chromatin was sensitive to changes in Cg levels. Proximity ligation assay indicated that the two proteins could reside in the same complex. Finally, chromatin conformation analysis revealed that EcR-bound regions within BR-C, which span ~30 KBs, contacted each other. Significantly, these contacts were stabilized in an ecdysone- and Combgap-dependent manner. Together, these results highlight Combgap as a novel regulator of chromatin structure that promotes transcription of ecdysone target genes and ovarian niche formation. PMID:27846223

Anti-HSV-1 and HSV-2 Flavonoids and a New Kaempferol Triglycoside from the Medicinal Plant Kalanchoe daigremontiana.

PubMed

Ürményi, Fernanda Gouvêa Gomes; Saraiva, Georgia do Nascimento; Casanova, Livia Marques; Matos, Amanda Dos Santos; de Magalhães Camargo, Luiza Maria; Romanos, Maria Teresa Villela; Costa, Sônia Soares

2016-12-01

Kalanchoe daigremontiana (Crassulaceae) is a medicinal plant native to Madagascar. The aim of this study was to investigate the flavonoid content of an aqueous leaf extract from K. daigremontiana (Kd), and assess its antiherpetic potential. The major flavonoid, kaempferol 3-O-β-d-xylopyranosyl-(1 → 2)-α-l-rhamnopyranoside (1), was isolated from the AcOEt fraction (Kd-AC). The BuOH-soluble fraction afforded quercetin 3-O-β-d-xylopyranosyl-(1 → 2)-α-l-rhamnopyranoside (2) and the new kaempferol 3-O-β-d-xylopyranosyl-(1 → 2)-α-l-rhamnopyranoside-7-O-β-d-glucopyranoside (3), named daigremontrioside. The crude extract, Kd-AC fraction, flavonoids 1 and 2 were evaluated using acyclovir-sensitive strains of HSV-1 and HSV-2. Kd-AC was highly active against HSV-1 (EC 50  = 0.97 μg/ml, SI > 206.1) and HSV-2 (EC 50  = 0.72 μg/ml, SI > 277.7). Flavonoids 1 and 2 showed anti-HSV-1 (EC 50  = 7.4 μg/ml; SI > 27 and EC 50  = 5.8 μg/ml; SI > 8.6, respectively) and anti-HSV-2 (EC 50  = 9.0 μg/ml; SI > 22.2 and EC 50  = 36.2 μg/ml; SI > 5.5, respectively) activities, suggesting the contribution of additional substances to the antiviral activity. © 2016 Wiley-VHCA AG, Zurich, Switzerland.

Tc-99m Ethylenedicysteine and Tc-99m Dimercaptosuccinic Acid Scintigraphy-Comparison of the Two for Detection of Scarring and Differential Cortical Function.

PubMed

Dharmalingam, Anitha; Pawar, Shwetal U; Parelkar, Sandesh V; Shetye, Suruchi S; Ghorpade, Mangala K; Tilve, Gundu H

2017-01-01

The differential cortical function obtained by Tc-99m EC is comparable to that of Tc-99m DMSA. However, identification of scars on Tc-99m EC images needs to be studied. The aim of the study is to evaluate role of Tc-99m EC for detection of scarring and differential cortical function by comparing with Tc-99m DMSA. Prospective observational study of recurrent UTI; minimum 6 weeks after acute episode; when urine examination is negative for pus cells. Forty-seven children with normal positioned kidneys underwent Tc-99m EC and DMSA scintigraphy. The DRF and cortical phase images of both studies in the same image matrix size were evaluated by two independent observers for scarring; Tc-99m DMSA was considered as the gold standard. MS Excel 2007 and GraphPad Instat V3.1 and ROC analysis. There was no significant difference in the detection of scarring using two studies with Cohen's kappa coefficient (κ) 0.932. The sensitivity and specificity of Tc-99m EC for detection of scarring was 98.75% and 99.15%, respectively. There was good agreement between the differential cortical function calculated using two studies. The summed Tc-99m EC images with an acceptable high image contrast allow detection of cortical scarring in patients with normal kidney positions. It is an excellent single-modality comprehensive investigational agent for renal parenchymal defects, function, and excretion evaluation with the added advantages of lower cost, convenience, and low radiation exposure to the child.

Are atmospheric updrafts a key to unlocking climate forcing and sensitivity?

DOE PAGES

Donner, Leo J.; O'Brien, Travis A.; Rieger, Daniel; ...

2016-10-20

Both climate forcing and climate sensitivity persist as stubborn uncertainties limiting the extent to which climate models can provide actionable scientific scenarios for climate change. A key, explicit control on cloud–aerosol interactions, the largest uncertainty in climate forcing, is the vertical velocity of cloud-scale updrafts. Model-based studies of climate sensitivity indicate that convective entrainment, which is closely related to updraft speeds, is an important control on climate sensitivity. Updraft vertical velocities also drive many physical processes essential to numerical weather prediction. Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climatemore » and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climate and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying vs in climate models may capture this behavior, but it has not been accounted for when parameterizing cloud and precipitation processes in current models. New observations of convective vertical velocities offer a potentially promising path toward developing process-level cloud models and parameterizations for climate and numerical weather prediction. Taking account of the scale dependence of resolved vertical velocities offers a path to matching cloud-scale physical processes and their driving dynamics more realistically, with a prospect of reduced uncertainty in both climate forcing and sensitivity.« less

Are atmospheric updrafts a key to unlocking climate forcing and sensitivity?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donner, Leo J.; O'Brien, Travis A.; Rieger, Daniel

Both climate forcing and climate sensitivity persist as stubborn uncertainties limiting the extent to which climate models can provide actionable scientific scenarios for climate change. A key, explicit control on cloud–aerosol interactions, the largest uncertainty in climate forcing, is the vertical velocity of cloud-scale updrafts. Model-based studies of climate sensitivity indicate that convective entrainment, which is closely related to updraft speeds, is an important control on climate sensitivity. Updraft vertical velocities also drive many physical processes essential to numerical weather prediction. Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climatemore » and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climate and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying vs in climate models may capture this behavior, but it has not been accounted for when parameterizing cloud and precipitation processes in current models. New observations of convective vertical velocities offer a potentially promising path toward developing process-level cloud models and parameterizations for climate and numerical weather prediction. Taking account of the scale dependence of resolved vertical velocities offers a path to matching cloud-scale physical processes and their driving dynamics more realistically, with a prospect of reduced uncertainty in both climate forcing and sensitivity.« less

Sensitivity and rapidity of vegetational response to abrupt climate change

NASA Technical Reports Server (NTRS)

Peteet, D.

2000-01-01

Rapid climate change characterizes numerous terrestrial sediment records during and since the last glaciation. Vegetational response is best expressed in terrestrial records near ecotones, where sensitivity to climate change is greatest, and response times are as short as decades.

National Forest management options in response to climate change

Treesearch

Forest Service U.S. Department of Agriculture

2009-01-01

The effect of climate change on ecosystem structure, function, and services will depend on the ecosystem's degree of sensitivity to climate change, the natural ability of plants and animals to adapt, and the availability of effective management options. Sensitivity to climate change is a function of ecosystem health and environmental stresses such as air pollution...

Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA

Treesearch

Heather T. Root; Bruce McCune; Sarah Jovan

2014-01-01

Because of their unique physiology, lichen communities are highly sensitive to climatic conditions,making them ideal bioindicators for climate change. Southeast and south-central Alaska host diverse and abundant lichen communities and are faced with a more rapidly changing climate than many more southerly latitudes. We develop sensitive lichen-based indicators for...

Tracing carbonaceous sources by using particulate carbon and sulfate in precipitation in Calgary, Alberta Canada

NASA Astrophysics Data System (ADS)

Ge, C.; Stenhouse, K. J.; Du, K.; Xing, Z.; Norman, A. L.

2016-12-01

Carbonaceous matter is often the dominant contributor to Particulate Matter (PM) which has a significant influence on climate, air quality and human health. The measurement of particulate carbon in rainfall in Calgary, Alberta has not been studied. This study reports the sulfate and the first concentrations of particulate carbon (PC) in rainfall in Calgary. It traces seasonal carbonaceous sources for the purpose of understanding sources for air quality control. Precipitation samples are collected twice a day at the University of Calgary. Thermo-optical methods are used to analyze concentrations of PC, including elemental carbon (EC), primary organic carbon (POC) and secondary organic carbon (SOC). Sulfate concentrations are measured using ion chromatography. In this study, sources from long range transport and local emissions are examined. We emphasized the apportionment of OC/EC in oil and gas emissions and diurnal variations in transportation emissions. Weekly average data for dry deposition were calculated to estimate the scavenging ratio of EC/POC/SOC and ions in precipitation. The results of this study will be presented with an emphasis on the relationship of carbonaceous material and sulfate. A range of apportionment methods have been applied to examine limitations in quantifying SOC in fall.

Sublethal Toxicity Endpoints of Heavy Metals to the Nematode Caenorhabditis elegans

PubMed Central

Wu, Yue; Wang, Qiang; Li, Huixin

2016-01-01

Caenorhabditis elegans, a free-living nematode, is commonly used as a model organism in ecotoxicological studies. The current literatures have provided useful insight into the relative sensitivity of several endpoints, but few direct comparisons of multiple endpoints under a common set of experimental conditions. The objective of this study was to determine appropriate sublethal endpoints to develop an ecotoxicity screening and monitoring system. C. elegans was applied to explore the sublethal toxicity of four heavy metals (copper, zinc, cadmium and chromium). Two physiological endpoints (growth and reproduction), three behavioral endpoints (head thrash frequency, body bend frequency and feeding) and two enzymatic endpoints (acetylcholine esterase [AChE] and superoxide dismutase [SOD]) were selected for the assessment of heavy metal toxicity. The squared correlation coefficients (R2) between the responses observed and fitted by Logit function were higher than 0.90 and the RMSE were lower than 0.10, indicating a good significance statistically. There was no significant difference among the half effect concentration (EC50) endpoints in physiological and behavioral effects of the four heavy metals, indicating similar sensitivity of physiological and behavioral effects. AChE enzyme was more sensitive to copper, zinc, and cadmium than to other physiological and behavioral effects, and SOD enzyme was most sensitive to chromium. The EC50 of copper, zinc, and cadmium, to the AChE enzyme in the nematodes were 0.68 mg/L, 2.76 mg/L, and 0.92 mg/L respectively and the EC50 of chromium to the SOD enzyme in the nematode was 1.58 mg/L. The results of this study showed that there was a good concentration-response relationship between all four heavy metals and the sublethal toxicity effects to C. elegans. Considering these sublethal endpoints in terms of simplicity, accuracy, repeatability and costs of the experiments, feeding is the relatively ideal sublethal toxicity endpoint of heavy metals to C. elegans. PMID:26824831

U.S. Government Supports Low Emission Economic Growth (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, A.; Sandor, D.; Butheau, M.

Countries around the world face the challenge of maintaining long-term sustainable economic growth and development under the threat of climate change. By identifying and pursuing a sustainable development pathway now, they are better positioned to reach their economic growth goals while addressing climate change impacts and lowering greenhouse gas (GHG) emissions. Low emission development strategies - development plans that promote sustainable social and economic development while reducing long-term GHG emissions - provide a pathway to preparing for a global low emission future. Partner country governments are working with the U.S. government through the Enhancing Capacity for Low Emission Development Strategiesmore » (EC-LEDS) program to further their national development objectives.« less

U.S. Government Supports Low Emission Economic Growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Countries around the world face the challenge of maintaining long-term sustainable economic growth and development under the threat of climate change. By identifying and pursuing a sustainable development pathway now, they are better positioned to reach their economic growth goals while addressing climate change impacts and lowering greenhouse gas (GHG) emissions. Low emission development strategies - development plans that promote sustainable social and economic development while reducing long-term GHG emissions - provide a pathway to preparing for a global low emission future. Partner country governments are working with the U.S. government through the Enhancing Capacity for Low Emission Development Strategiesmore » (EC-LEDS) program to further their national development objectives.« less

Local lymph node assay (LLNA) for detection of sensitization capacity of chemicals.

PubMed

Gerberick, G Frank; Ryan, Cindy A; Dearman, Rebecca J; Kimber, Ian

2007-01-01

The local lymph node assay (LLNA) is a murine model developed to evaluate the skin sensitization potential of chemicals. The LLNA is an alternative approach to traditional guinea pig methods and in comparison provides important animal welfare benefits. The assay relies on measurement of events induced during the induction phase of skin sensitization, specifically lymphocyte proliferation in the draining lymph nodes which is a hallmark of a skin sensitization response. Since its introduction the LLNA has been the subject of extensive evaluation on a national and international scale, and has been successfully validated and incorporated worldwide into regulatory guidelines. Experience gained in recent years has demonstrated that adherence to published procedures and guidelines for the LLNA (e.g., with respect to dose and vehicle selection) is critical for the successful conduct and eventual interpretation of the data. In addition to providing a robust method for skin sensitization hazard identification, the LLNA has proven very useful in assessing the skin sensitizing potency of test chemicals, and this has provided invaluable information to risk assessors. The primary method to make comparisons of the relative potency of chemical sensitizers is to use linear interpolation to estimate the concentration of chemical required to induce a stimulation index of three relative to concurrent vehicle-treated controls (EC3). In certain situations where there are available less than optimal dose response data a log-linear extrapolation method can be used to estimate an EC3 value which can reduce significantly the need for repeat testing of chemicals. The LLNA, when conducted according to published guidelines, provides a robust method for skin sensitization testing that not only provides reliable hazard identification information but also data necessary for effective risk assessment and risk management.

[A comparison between 3.0 T MRI and histopathology for preoperative T staging of potentially resectable esophageal cancer].

PubMed

Wang, Z Q; Zhang, F G; Guo, J; Zhang, H K; Qin, J J; Zhao, Y; Ding, Z D; Zhang, Z X; Zhang, J B; Yuan, J H; Li, H L; Qu, J R

2017-03-21

Objective: To explore the value of 3.0 T MRI using multiple sequences (star VIBE+ BLADE) in evaluating the preoperative T staging for potentially resectable esophageal cancer (EC). Methods: Between April 2015 and March 2016, a total of 66 consecutive patients with endoscopically proven resectable EC underwent 3.0T MRI in the Affiliated Cancer Hospital of Zhengzhou University.Two independent readers were assigned a T staging on MRI according to the 7th edition of UICC-AJCC TNM Classification, the results of preoperative T staging were compared and analyzed with post-operative pathologic confirmation. Results: The MRI T staging of two readers were highly consistent with histopathological findings, and the sensitivity, specificity and accuracy of preoperative T staging MR imaging were also very high. Conclusion: 3.0 T MRI using multiple sequences is with high accuracy for patients of potentially resectable EC in T staging. The staging accuracy of T1, T2 and T3 is better than that of T4a. 3.0T MRI using multiple sequences could be used as a noninvasive imaging method for pre-operative T staging of EC.

Comparison of sampling methods to measure HIV RNA viral load in female genital tract secretions.

PubMed

Jaumdally, Shameem Z; Jones, Heidi E; Hoover, Donald R; Gamieldien, Hoyam; Kriek, Jean-Mari; Langwenya, Nontokozo; Myer, Landon; Passmore, Jo-Ann S; Todd, Catherine S

2017-03-01

How does menstrual cup (MC) compare to other genital sampling methods for HIV RNA recovery? We compared HIV RNA levels between MC, endocervical swab (ECS), and ECS-enriched cervicovaginal lavage (eCVL) specimens in 51 HIV-positive, antiretroviral therapy-naive women at enrollment, 3 and 6 months, with order rotated by visit. Paired comparisons were analyzed with McNemar's exact tests, signed-rank tests, and an extension of Somer's D for pooled analyses across visits. MC specimens had the highest proportion of quantifiable HIV VL at enrollment and month 3, but more MC specimens (n=12.8%) were insufficient for testing, compared with ECS (2%, P=0.006) and eCVL (0%, P<0.001). Among sufficient specimens, median VL was significantly higher for MC (2.62 log 10 copies/mL) compared to ECS (1.30 log 10 copies/mL, P<0.001) and eCVL (1.60 log 10 copies/mL, P<0.001) across visits. MC may be more sensitive than eCVL and CVS, provided insufficient specimens are reduced. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Making Sense of Palaeoclimate Sensitivity

NASA Technical Reports Server (NTRS)

Rohling, E. J.; Sluijs, A.; DeConto, R.; Drijfhout, S. S.; Fedorov, A.; Foster, G. L.; Ganopolski, A.; Hansen, J.; Honisch, B.; Hooghiemstra, H.;

Chronic toxicity of five metals to the polar marine microalga Cryothecomonas armigera - Application of a new bioassay.

PubMed

Koppel, Darren J; Gissi, Francesca; Adams, Merrin S; King, Catherine K; Jolley, Dianne F

2017-09-01

The paucity of ecotoxicological data for Antarctic organisms is impeding the development of region-specific water quality guidelines. To address this limitation, toxicity testing protocols need to be developed to account for the unique physiology of polar organisms, in particular their slow growth rates. In this study, a toxicity test protocol was developed to investigate the toxicities of five metals to the polar marine microalga Cryothecomonas armigera. The concentrations which reduced population growth rate by 10% (EC10) after 24-d for Cu, Pb, Zn, Cd and Ni were 21.6, 152, 366, 454, and 1220 μg.L -1 , respectively. At the concentrations used in tests, only Cu and Ni were sufficiently toxic to enable the derivation of EC50 values of 63.1 and 1570 μg.L -1 respectively. All metals affected C. armigera's cellular physiology including cellular chlorophyll a fluorescence, cell complexity and size, and lipid concentrations. However, no changes to cellular membrane permeability were observed. The reduction in cellular lipid concentrations was a more sensitive indicator of toxicity for Cd, Ni, and Pb than growth rate inhibition, with EC10 values of 89, 894, and 11 μg.L -1 , respectively, highlighting its potential as a sensitive measure of metal toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

FLICE-like inhibitory protein (FLIP) protects against apoptosis and suppresses NF-kappaB activation induced by bacterial lipopolysaccharide.

PubMed

Bannerman, Douglas D; Eiting, Kristine T; Winn, Robert K; Harlan, John M

2004-10-01

Bacterial lipopolysaccharide (LPS) via its activation of Toll-like receptor-4 contributes to much of the vascular injury/dysfunction associated with gram-negative sepsis. Inhibition of de novo gene expression has been shown to sensitize endothelial cells (EC) to LPS-induced apoptosis, the onset of which correlates with decreased expression of FLICE-like inhibitory protein (FLIP). We now have data that conclusively establish a role for FLIP in protecting EC against LPS-induced apoptosis. Overexpression of FLIP protected against LPS-induced apoptosis, whereas down-regulation of FLIP using antisense oligonucleotides sensitized EC to direct LPS killing. Interestingly, FLIP overexpression suppressed NF-kappaB activation induced by LPS, but not by phorbol ester, suggesting a specific role for FLIP in mediating LPS activation. Conversely, mouse embryo fibroblasts (MEF) obtained from FLIP -/- mice showed enhanced LPS-induced NF-kappaB activation relative to those obtained from wild-type mice. Reconstitution of FLIP-/- MEF with full-length FLIP reversed the enhanced NF-kappaB activity elicited by LPS in the FLIP -/- cells. Changes in the expression of FLIP had no demonstrable effect on other known LPS/Tlr-4-activated signaling pathways including the p38, Akt, and Jnk pathways. Together, these data support a dual role for FLIP in mediating LPS-induced apoptosis and NF-kappaB activation.

Toxicity of triphenyltin and tributyltin to the freshwater mudsnail Potamopyrgus antipodarum in a new sediment biotest.

PubMed

Duft, Martina; Schulte-Oehlmann, Ulrike; Tillmann, Michaela; Markert, Bernd; Oehlmann, Jörg

2003-01-01

The effects of two suspected endocrine-disrupting chemicals, the xeno-androgens triphenyltin (TPT) and tributyltin (TBT), were investigated in a new whole-sediment biotest with the freshwater mudsnail Potamopyrgus antipodarum (Gastropoda, Prosobranchia). Artificial sediments were spiked with seven concentrations, ranging from 10 to 500 microg nominal TPT-Sn/kg dry weight and TBT-Sn/kg dry weight, respectively. We analyzed the responses of the test species after two, four, and eight weeks exposure. For both compounds, P. antipodarum exhibited a sharp decline in the number of embryos sheltered in its brood pouch in a time- and concentration-dependent manner in comparison to the control sediment. The number of new, still unshelled embryos turned out to be the most sensitive parameter. The lowest-observed-effect concentration (LOEC) was equivalent to the lowest administered concentration (10 microg/kg of each test compound) for most parameters and thus no no-observed-effect concentration (NOEC) could be established. The calculation of effect concentrations (EC10) resulted in even lower values for both substances (EC10 after eight weeks for unshelled embryos: 0.03 microg TPT-Sn/kg, EC10 after four weeks for unshelled embryos: 0.98 microg TBT-Sn/kg). Our results indicate that P. antipodarum is highly sensitive to both endocrine disruptors TPT and TBT at environmentally relevant concentrations.

Closure of the energy balance equation over bare soil during the formation and evaporation of non-rainfall water inputs

NASA Astrophysics Data System (ADS)

Florentin, Anat; Agam, Nurit

2015-04-01

The Negev desert is characterized by an arid climate (annual mean precipitation is 90 mm) with sea breeze carrying moisture from the Mediterranean Sea during the afternoon regularly. Non-rainfall water inputs (NRWIs) are thus of great importance to the hydrometeorology and the ecological functioning of the region. The small magnitude of NRWIs challenges attempts to quantify these processes. The aim of this research was to test commonly used micrometeorological methods to quantify the energy balance components during the deposition and evaporation of NRWIs. A fully equipped micrometeorological station was set up near the Blaustein Institutes for Desert Research of the Ben-Gurion University of the Negev (30o 51' 35.6" N; 34o 46' 24.8" E) during September-October 2014. Net-radiation was measured with a 4-way net radiometer, and soil heat flux was quantified by the calorimetric method in three replicates. Latent heat was measured using an eddy-covariance (EC) and compared to a micro-lysimeter (ML); sensible heat flux was measured with an EC and a surface layer scintillometer (SLS). Sensible heat fluxes measured by the EC and the SLS showed good agreement. EC latent heat fluxes were in good agreement with those derived by the ML. Nevertheless, derivation of latent heat flux from the SLS measurements through the energy balance equation showed a relatively large deviation from the directly measured latent heat flux. This deviation is likely attributed to measurement errors of the soil heat flux.

Integrating Eddy Covariance, Penman-Monteith and METRIC based Evapotranspiration estimates to generate high resolution space-time ET over the Brazos River Basin

NASA Astrophysics Data System (ADS)

Mbabazi, D.; Mohanty, B.; Gaur, N.

2017-12-01

Evapotranspiration (ET) is an important component of the water and energy balance and accounts for 60 -70% of precipitation losses. However, accurate estimates of ET are difficult to quantify at varying spatial and temporal scales. Eddy covariance methods estimate ET at high temporal resolutions but without capturing the spatial variation in ET within its footprint. On the other hand, remote sensing methods using Landsat imagery provide ET with high spatial resolution but low temporal resolution (16 days). In this study, we used both eddy covariance and remote sensing methods to generate high space-time resolution ET. Daily, monthly and seasonal ET estimates were obtained using the eddy covariance (EC) method, Penman-Monteith (PM) and Mapping Evapotranspiration with Internalized Calibration (METRIC) models to determine cotton and native prairie ET dynamics in the Brazos river basin characterized by varying hydro-climatic and geological gradients. Daily estimates of spatially distributed ET (30 m resolution) were generated using spatial autocorrelation and temporal interpolations between the EC flux variable footprints and METRIC ET for the 2016 and 2017 growing seasons. A comparison of the 2016 and 2017 preliminary daily ET estimates showed similar ET dynamics/trends among the EC, PM and METRIC methods, and 5-20% differences in seasonal ET estimates. This study will improve the spatial estimates of EC ET and temporal resolution of satellite derived ET thus providing better ET data for water use management.

Sensitivity of early life stages of freshwater mussels (Unionidae) to acute and chronic toxicity of lead, cadmium, and zinc in water

USGS Publications Warehouse

Wang, N.; Ingersoll, C.G.; Ivey, C.D.; Hardesty, D.K.; May, T.W.; Augspurger, T.; Roberts, A.D.; Van Genderen, E.; Barnhart, M.C.

2010-01-01

Toxicity of lead, cadmium, or zinc to early life stages of freshwater mussels (fatmucket, Lampsilis siliquoidea; Neosho mucket, L. rafinesqueana) was evaluated in 48-h exposures with mussel larvae (glochidia), in 96-h exposures with newly transformed (5-d-old) and two- or six-month-old juvenile mussels, or in 28-d exposures with two- or four-month-old mussels in reconstituted soft water. The 24-h median effect concentrations (EC50s) for fatmucket glochidia (>299??g Pb/L, >227??g Cd/L, 2,685??g Zn/L) and 96-h EC50s for two- or six-month-old fatmucket (>426??g Pb/L, 199??g Cd/L, 1,700??g Zn/L) were much higher than 96-h EC50s for newly transformed fatmucket (142 and 298??g Pb/L, 16??g Cd/L, 151 and 175??g Zn/L) and Neosho mucket (188??g Pb/L, 20??g Cd/L, 145??g Zn/L). Chronic values for fatmucket were 10??g Pb/L, 6.0??g Cd/L, and 63 and 68??g Zn/L. When mussel data from the present study and the literature were included in updated databases for deriving U.S. Environmental Protection Agency water quality criteria, mussel genus mean acute values were in the lower percentiles of the sensitivity distribution of all freshwater species for Pb (the 26th percentile), Cd (the 15th to 29th percentile), or Zn (the 12th to 21st percentile). The mussel (Lampsilis) genus mean chronic value was the lowest value ever reported for Pb (the 9th percentile) but was near the middle of the sensitivity distribution for Cd (the 61st percentile) or Zn (the 44th percentile). These results indicate that mussels were relatively sensitive to the acute toxicity of these three metals and to the chronic toxicity of Pb, but were moderately sensitive to the chronic toxicity of Cd or Zn compared to other freshwater species. ?? 2010 SETAC.

Sensitivity of early life stages of freshwater mussels (Unionidae) to acute and chronic toxicity of lead, cadmium, and zinc in water.

PubMed

Wang, Ning; Ingersoll, Christopher G; Ivey, Christopher D; Hardesty, Douglas K; May, Thomas W; Augspurger, Tom; Roberts, Andy D; van Genderen, Eric; Barnhart, M Chris

2010-09-01

Toxicity of lead, cadmium, or zinc to early life stages of freshwater mussels (fatmucket, Lampsilis siliquoidea; Neosho mucket, L. rafinesqueana) was evaluated in 48-h exposures with mussel larvae (glochidia), in 96-h exposures with newly transformed (5-d-old) and two- or six-month-old juvenile mussels, or in 28-d exposures with two- or four-month-old mussels in reconstituted soft water. The 24-h median effect concentrations (EC50s) for fatmucket glochidia (>299 microg Pb/L, >227 microg Cd/L, 2,685 microg Zn/L) and 96-h EC50s for two- or six-month-old fatmucket (>426 microg Pb/L, 199 microg Cd/L, 1,700 microg Zn/L) were much higher than 96-h EC50s for newly transformed fatmucket (142 and 298 microg Pb/L, 16 microg Cd/L, 151 and 175 microg Zn/L) and Neosho mucket (188 microg Pb/L, 20 microg Cd/L, 145 microg Zn/L). Chronic values for fatmucket were 10 microg Pb/L, 6.0 microg Cd/L, and 63 and 68 microg Zn/L. When mussel data from the present study and the literature were included in updated databases for deriving U.S. Environmental Protection Agency water quality criteria, mussel genus mean acute values were in the lower percentiles of the sensitivity distribution of all freshwater species for Pb (the 26th percentile), Cd (the 15th to 29th percentile), or Zn (the 12th to 21st percentile). The mussel (Lampsilis) genus mean chronic value was the lowest value ever reported for Pb (the 9th percentile) but was near the middle of the sensitivity distribution for Cd (the 61st percentile) or Zn (the 44th percentile). These results indicate that mussels were relatively sensitive to the acute toxicity of these three metals and to the chronic toxicity of Pb, but were moderately sensitive to the chronic toxicity of Cd or Zn compared to other freshwater species. Copyright 2010 SETAC.

The Green Tea Component (-)-Epigallocatechin-3-Gallate Sensitizes Primary Endothelial Cells to Arsenite-Induced Apoptosis by Decreasing c-Jun N-Terminal Kinase-Mediated Catalase Activity

PubMed Central

Lee, Hyeon-Ju; Byun, Catherine Jeonghae; Park, Jung-Hyun; Park, Jae Hoon; Cho, Ho-Seong; Cho, Sung-Jin; Jo, Sangmee Ahn; Jo, Inho

2015-01-01

The green tea component (-)-epigallocatechin-3-gallate (EGCG) has been shown to sensitize many different types of cancer cells to anticancer drug-induced apoptosis, although it protects against non-cancerous primary cells against toxicity from certain conditions such as exposure to arsenic (As) or ultraviolet irradiation. Here, we found that EGCG promotes As-induced toxicity of primary-cultured bovine aortic endothelial cells (BAEC) at doses in which treatment with each chemical alone had no such effect. Increased cell toxicity was accompanied by an increased condensed chromatin pattern and fragmented nuclei, cleaved poly(ADP-ribose) polymerase (PARP), activity of the pro-apoptotic enzymes caspases 3, 8 and 9, and Bax translocation into mitochondria, suggesting the involvement of an apoptotic signaling pathway. Fluorescence activated cell sorting analysis revealed that compared with EGCG or As alone, combined EGCG and As (EGCG/As) treatment significantly induced production of reactive oxygen species (ROS), which was accompanied by decreased catalase activity and increased lipid peroxidation. Pretreatment with N-acetyl-L-cysteine or catalase reversed EGCG/As-induced caspase activation and EC toxicity. EGCG/As also increased the phosphorylation of c-Jun N-terminal kinase (JNK), which was not reversed by catalase. However, pretreatment with the JNK inhibitor SP600125 reversed all of the observed effects of EGCG/As, suggesting that JNK may be the most upstream protein examined in this study. Finally, we also found that all the observed effects by EGCG/As are true for other types of EC tested. In conclusion, this is firstly to show that EGCG sensitizes non-cancerous EC to As-induced toxicity through ROS-mediated apoptosis, which was attributed at least in part to a JNK-activated decrease in catalase activity. PMID:26375285

The Green Tea Component (-)-Epigallocatechin-3-Gallate Sensitizes Primary Endothelial Cells to Arsenite-Induced Apoptosis by Decreasing c-Jun N-Terminal Kinase-Mediated Catalase Activity.

PubMed

Kim, Jee-Youn; Choi, Ji-Young; Lee, Hyeon-Ju; Byun, Catherine Jeonghae; Park, Jung-Hyun; Park, Jae Hoon; Cho, Ho-Seong; Cho, Sung-Jin; Jo, Sangmee Ahn; Jo, Inho

2015-01-01

The green tea component (-)-epigallocatechin-3-gallate (EGCG) has been shown to sensitize many different types of cancer cells to anticancer drug-induced apoptosis, although it protects against non-cancerous primary cells against toxicity from certain conditions such as exposure to arsenic (As) or ultraviolet irradiation. Here, we found that EGCG promotes As-induced toxicity of primary-cultured bovine aortic endothelial cells (BAEC) at doses in which treatment with each chemical alone had no such effect. Increased cell toxicity was accompanied by an increased condensed chromatin pattern and fragmented nuclei, cleaved poly(ADP-ribose) polymerase (PARP), activity of the pro-apoptotic enzymes caspases 3, 8 and 9, and Bax translocation into mitochondria, suggesting the involvement of an apoptotic signaling pathway. Fluorescence activated cell sorting analysis revealed that compared with EGCG or As alone, combined EGCG and As (EGCG/As) treatment significantly induced production of reactive oxygen species (ROS), which was accompanied by decreased catalase activity and increased lipid peroxidation. Pretreatment with N-acetyl-L-cysteine or catalase reversed EGCG/As-induced caspase activation and EC toxicity. EGCG/As also increased the phosphorylation of c-Jun N-terminal kinase (JNK), which was not reversed by catalase. However, pretreatment with the JNK inhibitor SP600125 reversed all of the observed effects of EGCG/As, suggesting that JNK may be the most upstream protein examined in this study. Finally, we also found that all the observed effects by EGCG/As are true for other types of EC tested. In conclusion, this is firstly to show that EGCG sensitizes non-cancerous EC to As-induced toxicity through ROS-mediated apoptosis, which was attributed at least in part to a JNK-activated decrease in catalase activity.

Metabolic features involved in drought stress tolerance mechanisms in peanut nodules and their contribution to biological nitrogen fixation.

PubMed

Furlan, Ana Laura; Bianucci, Eliana; Castro, Stella; Dietz, Karl-Josef

2017-10-01

Legumes belong to the most important crops worldwide. They increase soil fertility due their ability to establish symbiotic associations with soil microorganisms, known as rhizobia, capable of fixing nitrogen from the atmosphere. However, they are frequently exposed to abiotic stress conditions in particular drought. Such adverse conditions impair the biological nitrogen fixation (BNF) and depend largely on the legume. Therefore, two peanut cultivars with contrasting tolerance to drought, namely the more tolerant EC-98 and the sensitive Granoleico, were investigated to elucidate the relative contribution of BNF to the tolerance to drought. The tolerant cultivar EC-98 sustained growth and BNF similar to the control condition despite the reduced water potential and photosynthesis, suggesting the functioning of distinct metabolic pathways that contributed to enhance the tolerance. The biochemical and metabolomics approaches revealed that nodules from the tolerant cultivar accumulated trehalose, proline and gamma-aminobutyric acid (GABA), metabolites with known function in protecting against drought stress. The amide metabolism was severely affected in nodules from the sensitive cultivar Granoleico as revealed by the low content of asparagine and glutamine in the drought stressed plants. The sensitive cultivar upon rehydration was unable to re-establish a metabolism similar to well-watered plants. This was evidenced by the low level of metabolites and, transcripts and specific activities of enzymes from the carbon (sucrose synthase) and nitrogen (glutamine synthetase) metabolism which decreased below the values of control plants. Therefore, the increased content of metabolites with protective functions under drought stress likely is crucial for the full restoration upon rehydration. Smaller changes of drought stress-related metabolites in nodule are another trait that contributes to the effective control of BNF in the tolerant peanut cultivar (EC-98). Copyright © 2017 Elsevier B.V. All rights reserved.

Passive language mapping combining real-time oscillation analysis with cortico-cortical evoked potentials for awake craniotomy.

PubMed

Tamura, Yukie; Ogawa, Hiroshi; Kapeller, Christoph; Prueckl, Robert; Takeuchi, Fumiya; Anei, Ryogo; Ritaccio, Anthony; Guger, Christoph; Kamada, Kyousuke

2016-12-01

OBJECTIVE Electrocortical stimulation (ECS) is the gold standard for functional brain mapping; however, precise functional mapping is still difficult in patients with language deficits. High gamma activity (HGA) between 80 and 140 Hz on electrocorticography is assumed to reflect localized cortical processing, whereas the cortico-cortical evoked potential (CCEP) can reflect bidirectional responses evoked by monophasic pulse stimuli to the language cortices when there is no patient cooperation. The authors propose the use of "passive" mapping by combining HGA mapping and CCEP recording without active tasks during conscious resections of brain tumors. METHODS Five patients, each with an intraaxial tumor in their dominant hemisphere, underwent conscious resection of their lesion with passive mapping. The authors performed functional localization for the receptive language area, using real-time HGA mapping, by listening passively to linguistic sounds. Furthermore, single electrical pulses were delivered to the identified receptive temporal language area to detect CCEPs in the frontal lobe. All mapping results were validated by ECS, and the sensitivity and specificity were evaluated. RESULTS Linguistic HGA mapping quickly identified the language area in the temporal lobe. Electrical stimulation by linguistic HGA mapping to the identified temporal receptive language area evoked CCEPs on the frontal lobe. The combination of linguistic HGA and frontal CCEPs needed no patient cooperation or effort. In this small case series, the sensitivity and specificity were 93.8% and 89%, respectively. CONCLUSIONS The described technique allows for simple and quick functional brain mapping with higher sensitivity and specificity than ECS mapping. The authors believe that this could improve the reliability of functional brain mapping and facilitate rational and objective operations. Passive mapping also sheds light on the underlying physiological mechanisms of language in the human brain.

A new framework for climate sensitivity and prediction: a modelling perspective

NASA Astrophysics Data System (ADS)

Ragone, Francesco; Lucarini, Valerio; Lunkeit, Frank

2016-03-01

The sensitivity of climate models to increasing CO2 concentration and the climate response at decadal time-scales are still major factors of uncertainty for the assessment of the long and short term effects of anthropogenic climate change. While the relative slow progress on these issues is partly due to the inherent inaccuracies of numerical climate models, this also hints at the need for stronger theoretical foundations to the problem of studying climate sensitivity and performing climate change predictions with numerical models. Here we demonstrate that it is possible to use Ruelle's response theory to predict the impact of an arbitrary CO2 forcing scenario on the global surface temperature of a general circulation model. Response theory puts the concept of climate sensitivity on firm theoretical grounds, and addresses rigorously the problem of predictability at different time-scales. Conceptually, these results show that performing climate change experiments with general circulation models is a well defined problem from a physical and mathematical point of view. Practically, these results show that considering one single CO2 forcing scenario is enough to construct operators able to predict the response of climatic observables to any other CO2 forcing scenario, without the need to perform additional numerical simulations. We also introduce a general relationship between climate sensitivity and climate response at different time scales, thus providing an explicit definition of the inertia of the system at different time scales. This technique allows also for studying systematically, for a large variety of forcing scenarios, the time horizon at which the climate change signal (in an ensemble sense) becomes statistically significant. While what we report here refers to the linear response, the general theory allows for treating nonlinear effects as well. These results pave the way for redesigning and interpreting climate change experiments from a radically new perspective.

Climate Risk Assessment: Technical Guidance Manual for DoD Installations and Built Environment

DTIC Science & Technology

2016-09-06

climate change risks to DoD installations and the built environment. The approach, which we call “decision-scaling,” reveals the core sensitivity of...DoD installations to climate change . It is designed to illuminate the sensitivity of installations and their supporting infrastructure systems...including water and energy, to climate changes and other uncertainties without dependence on climate change projections. In this way the analysis and

Socio-climatic Exposure of an Afghan Poppy Farmer

NASA Astrophysics Data System (ADS)

Mankin, J. S.; Diffenbaugh, N. S.

2011-12-01

Many posit that climate impacts from anthropogenic greenhouse gas emissions will have consequences for the natural and agricultural systems on which humans rely for food, energy, and livelihoods, and therefore, on stability and human security. However, many of the potential mechanisms of action in climate impacts and human systems response, as well as the differential vulnerabilities of such systems, remain underexplored and unquantified. Here I present two initial steps necessary to characterize and quantify the consequences of climate change for farmer livelihood in Afghanistan, given both climate impacts and farmer vulnerabilities. The first is a conceptual model mapping the potential relationships between Afghanistan's climate, the winter agricultural season, and the country's political economy of violence and instability. The second is a utility-based decision model for assessing farmer response sensitivity to various climate impacts based on crop sensitivities. A farmer's winter planting decision can be modeled roughly as a tradeoff between cultivating the two crops that dominate the winter growing season-opium poppy (a climate tolerant cash crop) and wheat (a climatically vulnerable crop grown for household consumption). Early sensitivity analysis results suggest that wheat yield dominates farmer decision making variability; however, such initial results may dependent on the relative parameter ranges of wheat and poppy yields. Importantly though, the variance in Afghanistan's winter harvest yields of poppy and wheat is tightly linked to household livelihood and thus, is indirectly connected to the wider instability and insecurity within the country. This initial analysis motivates my focused research on the sensitivity of these crops to climate variability in order to project farmer well-being and decision sensitivity in a warmer world.

Development of graphene oxide/poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) thin film-based electrochemical surface plasmon resonance immunosensor for detection of human immunoglobulin G

NASA Astrophysics Data System (ADS)

Pothipor, Chammari; Lertvachirapaiboon, Chutiparn; Shinbo, Kazunari; Kato, Keizo; Kaneko, Futao; Ounnunkad, Kontad; Baba, Akira

2018-02-01

An electrochemically synthesized graphene oxide (GO)/poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(styrene sulfonate) (PSS) thin film-based electrochemical surface plasmon resonance (EC-SPR) sensor chip was developed and employed for the detection of human immunoglobulin G (IgG). GO introduced the carboxylic group on the film surface, which also allowed electrochemical control, for the immobilization of the anti-IgG antibody via covalent bonding through amide coupling reaction. The SPR sensitivity of the detection was improved under the control by applying an electrochemical potential, by which the sensitivity was increased by the increment in applied potential. Among the open-circuit and different applied potentials in the range of -1.0 to 0.50 V, the EC-SPR immunosensor at an applied potential of 0.50 V exhibited the highest sensitivity of 6.08 × 10-3 mL µg-1 cm-2 and linearity in the human IgG concentration range of 1.0 to 10 µg mL-1 with a relatively low detection limit of 0.35 µg mL-1. The proposed sensor chip is promising for immunosensing at the physiological level.

Climate sensitivity of shrub growth across the tundra biome

NASA Astrophysics Data System (ADS)

Myers-Smith, Isla H.; Elmendorf, Sarah C.; Beck, Pieter S. A.; Wilmking, Martin; Hallinger, Martin; Blok, Daan; Tape, Ken D.; Rayback, Shelly A.; Macias-Fauria, Marc; Forbes, Bruce C.; Speed, James D. M.; Boulanger-Lapointe, Noémie; Rixen, Christian; Lévesque, Esther; Schmidt, Niels Martin; Baittinger, Claudia; Trant, Andrew J.; Hermanutz, Luise; Collier, Laura Siegwart; Dawes, Melissa A.; Lantz, Trevor C.; Weijers, Stef; Jørgensen, Rasmus Halfdan; Buchwal, Agata; Buras, Allan; Naito, Adam T.; Ravolainen, Virve; Schaepman-Strub, Gabriela; Wheeler, Julia A.; Wipf, Sonja; Guay, Kevin C.; Hik, David S.; Vellend, Mark

2015-09-01

Rapid climate warming in the tundra biome has been linked to increasing shrub dominance. Shrub expansion can modify climate by altering surface albedo, energy and water balance, and permafrost, yet the drivers of shrub growth remain poorly understood. Dendroecological data consisting of multi-decadal time series of annual shrub growth provide an underused resource to explore climate-growth relationships. Here, we analyse circumpolar data from 37 Arctic and alpine sites in 9 countries, including 25 species, and ~42,000 annual growth records from 1,821 individuals. Our analyses demonstrate that the sensitivity of shrub growth to climate was: (1) heterogeneous, with European sites showing greater summer temperature sensitivity than North American sites, and (2) higher at sites with greater soil moisture and for taller shrubs (for example, alders and willows) growing at their northern or upper elevational range edges. Across latitude, climate sensitivity of growth was greatest at the boundary between the Low and High Arctic, where permafrost is thawing and most of the global permafrost soil carbon pool is stored. The observed variation in climate-shrub growth relationships should be incorporated into Earth system models to improve future projections of climate change impacts across the tundra biome.

Will Global Climate Change Alter Fundamental Human Immune Reactivity: Implications for Child Health?

PubMed

Swaminathan, Ashwin; Lucas, Robyn M; Harley, David; McMichael, Anthony J

2014-11-11

The human immune system is an interface across which many climate change sensitive exposures can affect health outcomes. Gaining an understanding of the range of potential effects that climate change could have on immune function will be of considerable importance, particularly for child health, but has, as yet, received minimal research attention. We postulate several mechanisms whereby climate change sensitive exposures and conditions will subtly impair aspects of the human immune response, thereby altering the distribution of vulnerability within populations-particularly for children-to infection and disease. Key climate change-sensitive pathways include under-nutrition, psychological stress and exposure to ambient ultraviolet radiation, with effects on susceptibility to infection, allergy and autoimmune diseases. Other climate change sensitive exposures may also be important and interact, either additively or synergistically, to alter health risks. Conducting directed research in this area is imperative as the potential public health implications of climate change-induced weakening of the immune system at both individual and population levels are profound. This is particularly relevant for the already vulnerable children of the developing world, who will bear a disproportionate burden of future adverse environmental and geopolitical consequences of climate change.

Are Atmospheric Updrafts a Key to Unlocking Climate Forcing and Sensitivity?

DOE PAGES

Donner, Leo J.; O'Brien, Travis A.; Rieger, Daniel; ...

2016-06-08

Both climate forcing and climate sensitivity persist as stubborn uncertainties limiting the extent to which climate models can provide actionable scientific scenarios for climate change. A key, explicit control on cloud-aerosol interactions, the largest uncertainty in climate forcing, is the vertical velocity of cloud-scale updrafts. Model-based studies of climate sensitivity indicate that convective entrainment, which is closely related to updraft speeds, is an important control on climate sensitivity. Updraft vertical velocities also drive many physical processes essential to numerical weather prediction. Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climatemore » and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying vertical velocities, and parameterizations which do provide vertical velocities have been subject to limited evaluation against what have until recently been scant observations. Atmospheric observations imply that the distribution of vertical velocities depends on the areas over which the vertical velocities are averaged. Distributions of vertical velocities in climate models may capture this behavior, but it has not been accounted for when parameterizing cloud and precipitation processes in current models. New observations of convective vertical velocities offer a potentially promising path toward developing process-level cloud models and parameterizations for climate and numerical weather prediction. Taking account of scale-dependence of resolved vertical velocities offers a path to matching cloud-scale physical processes and their driving dynamics more realistically, with a prospect of reduced uncertainty in both climate forcing and sensitivity.« less

Empirically Derived and Simulated Sensitivity of Vegetation to Climate Across Global Gradients of Temperature and Precipitation

NASA Astrophysics Data System (ADS)

Quetin, G. R.; Swann, A. L. S.

2017-12-01

Successfully predicting the state of vegetation in a novel environment is dependent on our process level understanding of the ecosystem and its interactions with the environment. We derive a global empirical map of the sensitivity of vegetation to climate using the response of satellite-observed greenness and leaf area to interannual variations in temperature and precipitation. Our analysis provides observations of ecosystem functioning; the vegetation interactions with the physical environment, across a wide range of climates and provide a functional constraint for hypotheses engendered in process-based models. We infer mechanisms constraining ecosystem functioning by contrasting how the observed and simulated sensitivity of vegetation to climate varies across climate space. Our analysis yields empirical evidence for multiple physical and biological mediators of the sensitivity of vegetation to climate as a systematic change across climate space. Our comparison of remote sensing-based vegetation sensitivity with modeled estimates provides evidence for which physiological mechanisms - photosynthetic efficiency, respiration, water supply, atmospheric water demand, and sunlight availability - dominate the ecosystem functioning in places with different climates. Earth system models are generally successful in reproducing the broad sign and shape of ecosystem functioning across climate space. However, this general agreement breaks down in hot wet climates where models simulate less leaf area during a warmer year, while observations show a mixed response but overall more leaf area during warmer years. In addition, simulated ecosystem interaction with temperature is generally larger and changes more rapidly across a gradient of temperature than is observed. We hypothesize that the amplified interaction and change are both due to a lack of adaptation and acclimation in simulations. This discrepancy with observations suggests that simulated responses of vegetation to global warming, and feedbacks between vegetation and climate, are too strong in the models.

Sensitivity of global terrestrial ecosystems to climate variability.

PubMed

Seddon, Alistair W R; Macias-Fauria, Marc; Long, Peter R; Benz, David; Willis, Kathy J

2016-03-10

The identification of properties that contribute to the persistence and resilience of ecosystems despite climate change constitutes a research priority of global relevance. Here we present a novel, empirical approach to assess the relative sensitivity of ecosystems to climate variability, one property of resilience that builds on theoretical modelling work recognizing that systems closer to critical thresholds respond more sensitively to external perturbations. We develop a new metric, the vegetation sensitivity index, that identifies areas sensitive to climate variability over the past 14 years. The metric uses time series data derived from the moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index, and three climatic variables that drive vegetation productivity (air temperature, water availability and cloud cover). Underlying the analysis is an autoregressive modelling approach used to identify climate drivers of vegetation productivity on monthly timescales, in addition to regions with memory effects and reduced response rates to external forcing. We find ecologically sensitive regions with amplified responses to climate variability in the Arctic tundra, parts of the boreal forest belt, the tropical rainforest, alpine regions worldwide, steppe and prairie regions of central Asia and North and South America, the Caatinga deciduous forest in eastern South America, and eastern areas of Australia. Our study provides a quantitative methodology for assessing the relative response rate of ecosystems--be they natural or with a strong anthropogenic signature--to environmental variability, which is the first step towards addressing why some regions appear to be more sensitive than others, and what impact this has on the resilience of ecosystem service provision and human well-being.

Sensitivity of global terrestrial ecosystems to climate variability

NASA Astrophysics Data System (ADS)

Seddon, Alistair W. R.; Macias-Fauria, Marc; Long, Peter R.; Benz, David; Willis, Kathy J.

2016-03-01

The identification of properties that contribute to the persistence and resilience of ecosystems despite climate change constitutes a research priority of global relevance. Here we present a novel, empirical approach to assess the relative sensitivity of ecosystems to climate variability, one property of resilience that builds on theoretical modelling work recognizing that systems closer to critical thresholds respond more sensitively to external perturbations. We develop a new metric, the vegetation sensitivity index, that identifies areas sensitive to climate variability over the past 14 years. The metric uses time series data derived from the moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index, and three climatic variables that drive vegetation productivity (air temperature, water availability and cloud cover). Underlying the analysis is an autoregressive modelling approach used to identify climate drivers of vegetation productivity on monthly timescales, in addition to regions with memory effects and reduced response rates to external forcing. We find ecologically sensitive regions with amplified responses to climate variability in the Arctic tundra, parts of the boreal forest belt, the tropical rainforest, alpine regions worldwide, steppe and prairie regions of central Asia and North and South America, the Caatinga deciduous forest in eastern South America, and eastern areas of Australia. Our study provides a quantitative methodology for assessing the relative response rate of ecosystems—be they natural or with a strong anthropogenic signature—to environmental variability, which is the first step towards addressing why some regions appear to be more sensitive than others, and what impact this has on the resilience of ecosystem service provision and human well-being.

Sensitivity of water resources in the Delaware River basin to climate variability and change

USGS Publications Warehouse

Ayers, Mark A.; Wolock, David M.; McCabe, Gregory J.; Hay, Lauren E.; Tasker, Gary D.

1993-01-01

Because of the "greenhouse effect," projected increases in atmospheric carbon dioxide levels might cause global warming, which in turn could result in changes in precipitation patterns and evapotranspiration and in increases in sea level. This report describes the greenhouse effect; discusses the problems and uncertainties associated with the detection, prediction, and effects of climatic change, and presents the results of sensitivity-analysis studies of the potential effects of climate change on water resources in the Delaware River basin. On the basis of sensitivity analyses, potentially serious shortfalls of certain water resources in the basin could result if some climatic-change scenarios become true. The results of basin streamflow-model simulations in this study demonstrate the difficulty in distinguishing effects of climatic change on streamflow and water supply from effects of natural variability in current climate. The future direction of basin changes in most water resources, furthermore, cannot be determined precisely because of uncertainty in current projections of regional temperature and precipitation. This large uncertainty indicates that, for resource planning, information defining the sensitivities of water resources to a range of climate change is most relevant. The sensitivity analyses could be useful in developing contingency plans on how to evaluate and respond to changes, should they occur.

Environmental health indicators of climate change for the United States: findings from the State Environmental Health Indicator Collaborative.

PubMed

English, Paul B; Sinclair, Amber H; Ross, Zev; Anderson, Henry; Boothe, Vicki; Davis, Christine; Ebi, Kristie; Kagey, Betsy; Malecki, Kristen; Shultz, Rebecca; Simms, Erin

2009-11-01

To develop public health adaptation strategies and to project the impacts of climate change on human health, indicators of vulnerability and preparedness along with accurate surveillance data on climate-sensitive health outcomes are needed. We researched and developed environmental health indicators for inputs into human health vulnerability assessments for climate change and to propose public health preventative actions. We conducted a review of the scientific literature to identify outcomes and actions that were related to climate change. Data sources included governmental and nongovernmental agencies and the published literature. Sources were identified and assessed for completeness, usability, and accuracy. Priority was then given to identifying longitudinal data sets that were applicable at the state and community level. We present a list of surveillance indicators for practitioners and policy makers that include climate-sensitive health outcomes and environmental and vulnerability indicators, as well as mitigation, adaptation, and policy indicators of climate change. A review of environmental health indicators for climate change shows that data exist for many of these measures, but more evaluation of their sensitivity and usefulness is needed. Further attention is necessary to increase data quality and availability and to develop new surveillance databases, especially for climate-sensitive morbidity.

Environmental Health Indicators of Climate Change for the United States: Findings from the State Environmental Health Indicator Collaborative

PubMed Central

English, Paul B.; Sinclair, Amber H.; Ross, Zev; Anderson, Henry; Boothe, Vicki; Davis, Christine; Ebi, Kristie; Kagey, Betsy; Malecki, Kristen; Shultz, Rebecca; Simms, Erin

2009-01-01

Objective To develop public health adaptation strategies and to project the impacts of climate change on human health, indicators of vulnerability and preparedness along with accurate surveillance data on climate-sensitive health outcomes are needed. We researched and developed environmental health indicators for inputs into human health vulnerability assessments for climate change and to propose public health preventative actions. Data sources We conducted a review of the scientific literature to identify outcomes and actions that were related to climate change. Data sources included governmental and nongovernmental agencies and the published literature. Data extraction Sources were identified and assessed for completeness, usability, and accuracy. Priority was then given to identifying longitudinal data sets that were applicable at the state and community level. Data synthesis We present a list of surveillance indicators for practitioners and policy makers that include climate-sensitive health outcomes and environmental and vulnerability indicators, as well as mitigation, adaptation, and policy indicators of climate change. Conclusions A review of environmental health indicators for climate change shows that data exist for many of these measures, but more evaluation of their sensitivity and usefulness is needed. Further attention is necessary to increase data quality and availability and to develop new surveillance databases, especially for climate-sensitive morbidity. PMID:20049116

Evaluation of relative potencies for in vitro transactivation of the baikal seal aryl hydrocarbon receptor by dioxin-like compounds.

PubMed

Kim, Eun-Young; Suda, Tomoko; Tanabe, Shinsuke; Batoev, Valeriy B; Petrov, Evgeny A; Iwata, Hisato

2011-02-15

To evaluate the sensitivity and responses to dioxins and related compounds (DRCs) via aryl hydrocarbon receptor (AHR) in Baikal seals (Pusa sibirica), we constructed an in vitro reporter gene assay system. Baikal seal AHR (BS AHR) expression plasmid and a reporter plasmid containing CYP1A1 promoter were transfected in COS-7 cells. The cells were treated with six representative congeners, and dose-dependent responses were obtained for all the congeners. EC50 values of 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 2,3,7,8-TCDF, 2,3,4,7,8-PeCDF, and PCB126 were found to be 0.021, 1.8, 0.16, 2.4, and 2.5 nM, respectively. As the response did not reach the maximal plateau, EC50 value for PCB118 could not be obtained. The TCDD-EC50 for BS AHR was as high as that for dioxin sensitive C57BL/6 mouse AHR. The in vitro dose responses were further analyzed following an established systematic framework and multiple (20, 50, and 80%) relative potencies (REPs) to the maximum TCDD response. The estimates revealed lower REP ranges (20-80%) of PeCDD and PeCDF for BS AHR than for mouse AHR. Average of the 20, 50, and 80% REPs was designated as Baikal seal specific TCDD induction equivalency factor (BS IEF). The BS IEFs of PeCDD, TCDF, PeCDF, PCB126, and PCB118 were estimated as 0.010, 0.018, 0.0078, 0.0059, and 0.00010, respectively. Total TCDD induction equivalents (IEQs) that were calculated using BS IEFs and hepatic concentrations in wild Baikal seals corresponded to only 12-31% of 2005 WHO TEF-derived TEQs. Nevertheless, about 50% of Baikal seals accumulated IEQs over the TCDD-EC50 obtained in this study. This assessment was supported by the enhanced CYP1A1 mRNA expression found in 50% of the specimens contaminated over the TCDD-EC50. These findings suggest that the IEFs proposed from this in vitro assay could be used to predict AHR-mediated responses in wild seals.

A simple scaling approach to produce climate scenarios of local precipitation extremes for the Netherlands

NASA Astrophysics Data System (ADS)

Lenderink, Geert; Attema, Jisk

2015-08-01

Scenarios of future changes in small scale precipitation extremes for the Netherlands are presented. These scenarios are based on a new approach whereby changes in precipitation extremes are set proportional to the change in water vapor amount near the surface as measured by the 2m dew point temperature. This simple scaling framework allows the integration of information derived from: (i) observations, (ii) a new unprecedentedly large 16 member ensemble of simulations with the regional climate model RACMO2 driven by EC-Earth, and (iii) short term integrations with a non-hydrostatic model Harmonie. Scaling constants are based on subjective weighting (expert judgement) of the three different information sources taking also into account previously published work. In all scenarios local precipitation extremes increase with warming, yet with broad uncertainty ranges expressing incomplete knowledge of how convective clouds and the atmospheric mesoscale circulation will react to climate change.

Investigations of 2β decay of {sup 106}Cd and {sup 58}Ni with HPGe spectrometer OBELIX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rukhadze, E.; Fajt, L.; Hodák, R.

2015-08-17

Investigations of double beta decay processes to excited states of daughter nuclei were performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using the high sensitivity spectrometer OBELIX [1], which is a common activity of JINR Dubna, IEAP CTU in Prague and LSM. The spectrometer is based on the HPGe detector with the sensitive volume of 600 cm{sup 3} and relative efficiency of 160%. Investigation of resonant neutrino-less double electron capture of {sup 106}Cd was performed with ∼23.2 g of {sup 106}Cd (enrichment of 99.57%) during ∼17 days. The experiment with natural Ni (∼21.7 kg of mass) was also carried out duringmore » ∼47 days. The preliminary experimental limits for 0νEC/EC resonant decay to the excited states of {sup 106}Pd and different modes of β β decay {sup 58}Ni are presented.« less

Sensitivity of ocean acidification and oxygen to the uncertainty in climate change

NASA Astrophysics Data System (ADS)

Cao, Long; Wang, Shuangjing; Zheng, Meidi; Zhang, Han

2014-05-01

Due to increasing atmospheric CO2 concentrations and associated climate change, the global ocean is undergoing substantial physical and biogeochemical changes. Among these, changes in ocean oxygen and carbonate chemistry have great implication for marine biota. There is considerable uncertainty in the projections of future climate change, and it is unclear how the uncertainty in climate change would also affect the projection of oxygen and carbonate chemistry. To investigate this issue, we use an Earth system model of intermediate complexity to perform a set of simulations, including that which involves no radiative effect of atmospheric CO2 and those which involve CO2-induced climate change with climate sensitivity varying from 0.5 °C to 4.5 °C. Atmospheric CO2 concentration is prescribed to follow RCP 8.5 pathway and its extensions. Climate change affects carbonate chemistry and oxygen mainly through its impact on ocean temperature, ocean ventilation, and concentration of dissolved inorganic carbon and alkalinity. It is found that climate change mitigates the decrease of carbonate ions at the ocean surface but has negligible effect on surface ocean pH. Averaged over the whole ocean, climate change acts to decrease oxygen concentration but mitigates the CO2-induced reduction of carbonate ion and pH. In our simulations, by year 2500, every degree increase of climate sensitivity warms the ocean by 0.8 °C and reduces ocean-mean dissolved oxygen concentration by 5.0%. Meanwhile, every degree increase of climate sensitivity buffers CO2-induced reduction in ocean-mean carbonate ion concentration and pH by 3.4% and 0.02 units, respectively. Our study demonstrates different sensitivities of ocean temperature, carbonate chemistry, and oxygen, in terms of both the sign and magnitude to the amount of climate change, which have great implications for understanding the response of ocean biota to climate change.

Assessing variability in chemical acute toxicity of unionid mussels: Influence of intra- and inter-laboratory testing, life stage, and species

USGS Publications Warehouse

Raimondo, Sandy; Lilavois, Crystal R.; Lee, Larisa; Augspurger, Tom; Wang, Ning; Ingersoll, Christopher G.; Bauer, Candice R.; Hammer, Edward J.; Barron, Mace G.

2016-01-01

We developed a toxicity database for unionid mussels to examine the extent of intra- and inter-laboratory variability in acute toxicity tests with mussel larvae (glochidia) and juveniles; the extent of differential sensitivity of the two life stages; and the variation in sensitivity among commonly tested mussels (Lampsilis siliquoidea, Utterbackia imbecillis, Villosa iris), commonly tested cladocerans (Daphnia magna, Ceriodaphnia dubia) and fish (Oncorhynchus mykiss, Pimephales promelas, Lepomis macrochirus). The results of these analyses indicate intra-laboratory variability for median effect concentrations (EC50) averaged about 2 fold for both life stages, while inter-laboratory variability averaged 3.6 fold for juvenile mussels and 6.3 fold for glochidia. The EC50s for juveniles and glochidia were within a factor of 2 of each other for 50% of paired records across chemicals, with juveniles more sensitive than glochidia by more than 2 fold for 33% of the comparisons made between life stages. There was a high concurrence of the sensitivity of commonly tested L. siliquoidea, U. imbecillis, and V. iris to that of other mussels. However, this concurrence decreases as the taxonomic distance of the commonly tested cladocerans and fish to mussels increases. The compiled mussel database and determination of data variability will advance risk assessments by including more robust species sensitivity distributions, interspecies correlation estimates, and availability of taxon-specific empirically derived application factors for risk assessment.

A Data-Driven Assessment of the Sensitivity of Global Ecosystems to Climate Anomalies

NASA Astrophysics Data System (ADS)

Miralles, D. G.; Papagiannopoulou, C.; Demuzere, M.; Decubber, S.; Waegeman, W.; Verhoest, N.; Dorigo, W.

2017-12-01

Vegetation is a central player in the climate system, constraining atmospheric conditions through a series of feedbacks. This fundamental role highlights the importance of understanding regional drivers of ecological sensitivity and the response of vegetation to climatic changes. While nutrient availability and short-term disturbances can be crucial for vegetation at various spatiotemporal scales, natural vegetation dynamics are overall driven by climate. At monthly scales, the interactions between vegetation and climate become complex: some vegetation types react preferentially to specific climatic changes, with different levels of intensity, resilience and lagged response. For our current Earth System Models (ESMs) being able to capture this complexity is crucial but extremely challenging. This adds uncertainty to our projections of future climate and the fate of global ecosystems. Here, following a Granger causality framework based on a non-linear random forest predictive model, we exploit the current wealth of satellite data records to uncover the main climatic drivers of monthly vegetation variability globally. Results based on three decades of satellite data indicate that water availability is the most dominant factor driving vegetation in over 60% of the vegetated land. This overall dependency of ecosystems on water availability is larger than previously reported, partly owed to the ability of our machine-learning framework to disentangle the co-linearites between climatic drivers, and to quantify non-linear impacts of climate on vegetation. Our observation-based results are then used to benchmark ESMs on their representation of vegetation sensitivity to climate and climatic extremes. Our findings indicate that the sensitivity of vegetation to climatic anomalies is ill-reproduced by some widely-used ESMs.

Modeling Soil Organic Carbon Variation Along Climatic and Topographic Trajectories in the Central Andes

NASA Astrophysics Data System (ADS)

Gavilan, C.; Grunwald, S.; Quiroz, R.; Zhu, L.

2015-12-01

The Andes represent the largest and highest mountain range in the tropics. Geological and climatic differentiation favored landscape and soil diversity, resulting in ecosystems adapted to very different climatic patterns. Although several studies support the fact that the Andes are a vast sink of soil organic carbon (SOC) only few have quantified this variable in situ. Estimating the spatial distribution of SOC stocks in data-poor and/or poorly accessible areas, like the Andean region, is challenging due to the lack of recent soil data at high spatial resolution and the wide range of coexistent ecosystems. Thus, the sampling strategy is vital in order to ensure the whole range of environmental covariates (EC) controlling SOC dynamics is represented. This approach allows grasping the variability of the area, which leads to more efficient statistical estimates and improves the modeling process. The objectives of this study were to i) characterize and model the spatial distribution of SOC stocks in the Central Andean region using soil-landscape modeling techniques, and to ii) validate and evaluate the model for predicting SOC content in the area. For that purpose, three representative study areas were identified and a suite of variables including elevation, mean annual temperature, annual precipitation and Normalized Difference Vegetation Index (NDVI), among others, was selected as EC. A stratified random sampling (namely conditioned Latin Hypercube) was implemented and a total of 400 sampling locations were identified. At all sites, four composite topsoil samples (0-30 cm) were collected within a 2 m radius. SOC content was measured using dry combustion and SOC stocks were estimated using bulk density measurements. Regression Kriging was used to map the spatial variation of SOC stocks. The accuracy, fit and bias of SOC models was assessed using a rigorous validation assessment. This study produced the first comprehensive, geospatial SOC stock assessment in this undersampled region that serves as a baseline reference to assess potential impacts of climate and land use change.

Improved Upper Ocean/Sea Ice Modeling in the GISS GCM for Investigating Climate Change

NASA Technical Reports Server (NTRS)

1997-01-01

This project built on our previous results in which we highlighted the importance of sea ice in overall climate sensitivity by determining that for both warming and cooling climates, when sea ice was not allowed to change, climate sensitivity was reduced by 35-40%. We also modified the Goddard Institute for Space Studies (GISS) 8 deg x lO deg atmospheric General Circulation Model (GCM) to include an upper-ocean/sea-ice model involving the Semtner three-layer ice/snow thermodynamic model, the Price et al. (1986) ocean mixed layer model and a general upper ocean vertical advection/diffusion scheme for maintaining and fluxing properties across the pycnocline. This effort, in addition to improving the sea ice representation in the AGCM, revealed a number of sensitive components of the sea ice/ocean system. For example, the ability to flux heat through the ice/snow properly is critical in order to resolve the surface temperature properly, since small errors in this lead to unrestrained climate drift. The present project, summarized in this report, had as its objectives: (1) introducing a series of sea ice and ocean improvements aimed at overcoming remaining weaknesses in the GCM sea ice/ocean representation, and (2) performing a series of sensitivity experiments designed to evaluate the climate sensitivity of the revised model to both Antarctic and Arctic sea ice, determine the sensitivity of the climate response to initial ice distribution, and investigate the transient response to doubling CO2.

Improved Upper Ocean/Sea Ice Modeling in the GISS GCM for Investigating Climate Change

NASA Technical Reports Server (NTRS)

1998-01-01

This project built on our previous results in which we highlighted the importance of sea ice in overall climate sensitivity by determining that for both warming and cooling climates, when sea ice was not allowed to change, climate sensitivity was reduced by 35-40%. We also modified the GISS 8 deg x lO deg atmospheric GCM to include an upper-ocean/sea-ice model involving the Semtner three-layer ice/snow thermodynamic model, the Price et al. (1986) ocean mixed layer model and a general upper ocean vertical advection/diffusion scheme for maintaining and fluxing properties across the pycnocline. This effort, in addition to improving the sea ice representation in the AGCM, revealed a number of sensitive components of the sea ice/ocean system. For example, the ability to flux heat through the ice/snow properly is critical in order to resolve the surface temperature properly, since small errors in this lead to unrestrained climate drift. The present project, summarized in this report, had as its objectives: (1) introducing a series of sea ice and ocean improvements aimed at overcoming remaining weaknesses in the GCM sea ice/ocean representation, and (2) performing a series of sensitivity experiments designed to evaluate the climate sensitivity of the revised model to both Antarctic and Arctic sea ice, determine the sensitivity of the climate response to initial ice distribution, and investigate the transient response to doubling CO2.

How does the terrestrial carbon exchange respond to inter-annual climatic variations? A quantification based on atmospheric CO2 data

NASA Astrophysics Data System (ADS)

Rödenbeck, Christian; Zaehle, Sönke; Keeling, Ralph; Heimann, Martin

2018-04-01

The response of the terrestrial net ecosystem exchange (NEE) of CO2 to climate variations and trends may crucially determine the future climate trajectory. Here we directly quantify this response on inter-annual timescales by building a linear regression of inter-annual NEE anomalies against observed air temperature anomalies into an atmospheric inverse calculation based on long-term atmospheric CO2 observations. This allows us to estimate the sensitivity of NEE to inter-annual variations in temperature (seen as a climate proxy) resolved in space and with season. As this sensitivity comprises both direct temperature effects and the effects of other climate variables co-varying with temperature, we interpret it as inter-annual climate sensitivity. We find distinct seasonal patterns of this sensitivity in the northern extratropics that are consistent with the expected seasonal responses of photosynthesis, respiration, and fire. Within uncertainties, these sensitivity patterns are consistent with independent inferences from eddy covariance data. On large spatial scales, northern extratropical and tropical inter-annual NEE variations inferred from the NEE-T regression are very similar to the estimates of an atmospheric inversion with explicit inter-annual degrees of freedom. The results of this study offer a way to benchmark ecosystem process models in more detail than existing effective global climate sensitivities. The results can also be used to gap-fill or extrapolate observational records or to separate inter-annual variations from longer-term trends.

Increased sensitivity to climate change in disturbed ecosystems.

PubMed

Kröel-Dulay, György; Ransijn, Johannes; Schmidt, Inger Kappel; Beier, Claus; De Angelis, Paolo; de Dato, Giovanbattista; Dukes, Jeffrey S; Emmett, Bridget; Estiarte, Marc; Garadnai, János; Kongstad, Jane; Kovács-Láng, Edit; Larsen, Klaus Steenberg; Liberati, Dario; Ogaya, Romà; Riis-Nielsen, Torben; Smith, Andrew R; Sowerby, Alwyn; Tietema, Albert; Penuelas, Josep

2015-03-24

Human domination of the biosphere includes changes to disturbance regimes, which push many ecosystems towards early-successional states. Ecological theory predicts that early-successional ecosystems are more sensitive to perturbations than mature systems, but little evidence supports this relationship for the perturbation of climate change. Here we show that vegetation (abundance, species richness and species composition) across seven European shrublands is quite resistant to moderate experimental warming and drought, and responsiveness is associated with the dynamic state of the ecosystem, with recently disturbed sites responding to treatments. Furthermore, most of these responses are not rapid (2-5 years) but emerge over a longer term (7-14 years). These results suggest that successional state influences the sensitivity of ecosystems to climate change, and that ecosystems recovering from disturbances may be sensitive to even modest climatic changes. A research bias towards undisturbed ecosystems might thus lead to an underestimation of the impacts of climate change.

Twinning European and South Asian river basins to enhance capacity and implement adaptive integrated water resources management approaches - results from the EC-project BRAHMATWINN

NASA Astrophysics Data System (ADS)

Flügel, W.-A.

2011-04-01

The EC-project BRAHMATWINN was carrying out a harmonised integrated water resources management (IWRM) approach as addressed by the European Water Initiative (EWI) in headwater river systems of alpine mountain massifs of the twinning Upper Danube River Basin (UDRB) and the Upper Brahmaputra River Basins (UBRB) in Europe and Southeast Asia respectively. Social and natural scientists in cooperation with water law experts and local stakeholders produced the project outcomes presented in Chapter 2 till Chapter 10 of this publication. BRAHMATWINN applied a holistic approach towards IWRM comprising climate modelling, socio-economic and governance analysis and concepts together with methods and integrated tools of applied Geoinformatics. A detailed description of the deliverables produced by the BRAHMATWINN project is published on the project homepage http://www.brahmatwinn.uni-jena.de.

Different sensitivities of snowpacks to warming in Mediterranean climate mountain areas

NASA Astrophysics Data System (ADS)

López-Moreno, J. I.; Gascoin, S.; Herrero, J.; Sproles, E. A.; Pons, M.; Alonso-González, E.; Hanich, L.; Boudhar, A.; Musselman, K. N.; Molotch, N. P.; Sickman, J.; Pomeroy, J.

2017-07-01

In this study we quantified the sensitivity of snow to climate warming in selected mountain sites having a Mediterranean climate, including the Pyrenees in Spain and Andorra, the Sierra Nevada in Spain and California (USA), the Atlas in Morocco, and the Andes in Chile. Meteorological observations from high elevations were used to simulate the snow energy and mass balance (SEMB) and calculate its sensitivity to climate. Very different climate sensitivities were evident amongst the various sites. For example, reductions of 9%-19% and 6-28 days in the mean snow water equivalent (SWE) and snow duration, respectively, were found per °C increase. Simulated changes in precipitation (±20%) did not affect the sensitivities. The Andes and Atlas Mountains have a shallow and cold snowpack, and net radiation dominates the SEMB; and explains their relatively low sensitivity to climate warming. The Pyrenees and USA Sierra Nevada have a deeper and warmer snowpack, and sensible heat flux is more important in the SEMB; this explains the much greater sensitivities of these regions. Differences in sensitivity help explain why, in regions where climate models project relatively greater temperature increases and drier conditions by 2050 (such as the Spanish Sierra Nevada and the Moroccan Atlas Mountains), the decline in snow accumulation and duration is similar to other sites (such as the Pyrenees and the USA Sierra Nevada), where models project stable precipitation and more attenuated warming. The snowpack in the Andes (Chile) exhibited the lowest sensitivity to warming, and is expected to undergo only moderate change (a decrease of <12% in mean SWE, and a reduction of < 7 days in snow duration under RCP 4.5). Snow accumulation and duration in the other regions are projected to decrease substantially (a minimum of 40% in mean SWE and 15 days in snow duration) by 2050.

Using Bioassays and Species Sensitivity Distributions to Assess Herbicide Toxicity towards Benthic Diatoms

PubMed Central

Larras, Floriane; Bouchez, Agnès; Rimet, Frédéric; Montuelle, Bernard

2012-01-01

Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD) could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC5) and the Effective Concentration 50 (EC50) for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC5) and 50 (HC50). Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII) herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and “motile” guild species were more tolerant of PSII inhibitors, while N-autotroph and “low profile” guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron. PMID:22952981

The sensitivity of an hydroponic lettuce root elongation bioassay to metals, phenol and wastewaters.

PubMed

Park, Jihae; Yoon, Jeong-Hyun; Depuydt, Stephen; Oh, Jung-Woo; Jo, Youn-Min; Kim, Kyungtae; Brown, Murray T; Han, Taejun

2016-04-01

The root elongation bioassay is one of the most straightforward test methods used for environmental monitoring in terms of simplicity, rapidity and economy since it merely requires filter paper, distilled water and Petri dishes. However, filter paper as a support material is known to be problematic as it can reduce the sensitivity of the test. The newly developed hydroponic method reported here differs from the conventional root elongation method (US EPA filter paper method) in that no support material is used and the exposure time is shorter (48 h in this test versus 120 h in the US EPA test). For metals, the hydroponic test method was 3.3 (for Hg) to 57 (for Cu) times more sensitive than the US EPA method with the rank orders of sensitivity, estimated from EC50 values, being Cu≥Cd>Ni≥Zn≥Hg for the former and Hg≥Cu≥Ni≥Cd≥Zn for the latter methods. For phenol, the results did not differ significantly; EC50 values were 124 mg L(-1) and 108-180 mg L(-1) for the hydroponic and filter paper methods, respectively. Lettuce was less sensitive than daphnids to wastewaters, but the root elongation response appears to be wastewater-specific and is especially sensitive for detecting the presence of fluorine. The new hydroponic test thus provides many practical advantages, especially in terms of cost and time-effectiveness requiring only a well plate, a small volume of distilled water and short exposure period; furthermore, no specialist expertise is required. The method is simpler than the conventional EPA technique in not using filter paper which can influence the sensitivity of the test. Additionally, plant seeds have a long shelf-life and require little or no maintenance. Copyright © 2015 Elsevier Inc. All rights reserved.

Critical Climate-Sensitive and Important Grain-Producing Regions: Grain Production/Yield Variations Due to Climate Fluctuations. Volume 1

NASA Technical Reports Server (NTRS)

Welker, J. E.

2004-01-01

Ideally, the Crop Country Inventory, CCI, is a methodology for the pre-harvest prediction of large variations in a country s crop production. This is accomplished by monitoring the historical climatic fluctuations, especially during the crop calendar period, in a climate sensitive large crop production region or sub-country, rather than the entire country. The argument can be made that the climatic fluctuations in the climatic sensitive region are responsible for the major annual crop country variations and that the remainder of the country, without major climatic fluctuations for a given year, can be assumed to be a steady-state crop producer. The principal data set that has been used is the Global Climate Mode (GCM) data from the National Center for Environmental Prediction (NCEP), taken over the last half century. As a test of its accuracy, GCM data can and has been correlated with the actual meteorological station data at the station site.