Science.gov

Sample records for change climate-chemistry interactions

  1. Atmospheric Composition Change: Climate-Chemistry Interactions

    NASA Technical Reports Server (NTRS)

    Isaksen, I.S.A.; Granier, C.; Myhre, G.; Bernsten, T. K.; Dalsoren, S. B.; Gauss, S.; Klimont, Z.; Benestad, R.; Bousquet, P.; Collins, W.; Cox, T.; Eyring, V.; Fowler, D.; Fuzzi, S.; Jockel, P.; Laj, P.; Lohmann, U.; Maione, M.; Monks, T.; Prevot, A. S. H.; Raes, F.; Richter, A.; Rognerud, B.; Schulz, M.; Shindell, D.; Stevenson, D. S.; Storelvmo, T.; Wang, W.-C.; vanWeele, M.; Wild, M.; Wuebbles, D.

    2011-01-01

    Chemically active climate compounds are either primary compounds such as methane (CH4), removed by oxidation in the atmosphere, or secondary compounds such as ozone (O3), sulfate and organic aerosols, formed and removed in the atmosphere. Man-induced climate-chemistry interaction is a two-way process: Emissions of pollutants change the atmospheric composition contributing to climate change through the aforementioned climate components, and climate change, through changes in temperature, dynamics, the hydrological cycle, atmospheric stability, and biosphere-atmosphere interactions, affects the atmospheric composition and oxidation processes in the troposphere. Here we present progress in our understanding of processes of importance for climate-chemistry interactions, and their contributions to changes in atmospheric composition and climate forcing. A key factor is the oxidation potential involving compounds such as O3 and the hydroxyl radical (OH). Reported studies represent both current and future changes. Reported results include new estimates of radiative forcing based on extensive model studies of chemically active climate compounds such as O3, and of particles inducing both direct and indirect effects. Through EU projects such as ACCENT, QUANTIFY, and the AEROCOM project, extensive studies on regional and sector-wise differences in the impact on atmospheric distribution are performed. Studies have shown that land-based emissions have a different effect on climate than ship and aircraft emissions, and different measures are needed to reduce the climate impact. Several areas where climate change can affect the tropospheric oxidation process and the chemical composition are identified. This can take place through enhanced stratospheric-tropospheric exchange of ozone, more frequent periods with stable conditions favouring pollution build up over industrial areas, enhanced temperature-induced biogenic emissions, methane releases from permafrost thawing, and enhanced

  2. SPARC-IGAC Symposium on Climate-Chemistry Interactions. Climate Feedback by Water Vapor in the Tropical Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Dessler, A. E.; Minschwaner, K.

    2003-01-01

    The strong greenhouse forcing by atmospheric water vapor is expected to play an important role in shaping the direction of any future changes in climate. We present calculations that provide a new perspective on the sensitivity of upper tropospheric water vapor to changes in surface temperature. Equilibrium states of our atmospheric model show unambiguously that as the surface warms, changes in the vertical distribution and temperature of detraining air parcels from tropical convection lead to higher water vapor mixing ratios in the upper troposphere. However, the increase in mixing ratio is not as large as the increase in saturation mixing ratio due to warmer environmental temperatures, so that the relative humidity decreases. Our analysis suggests that models that maintain a fixed relative humidity are likely overestimating the magnitude of the water vapor feedback.

  3. Assessing the climatic effect of carbon dioxide and other trace gases using an interactive two-dimensional climate-chemistry model. Final report, December 1992--August 1996

    SciTech Connect

    Ko, M.K.W.

    1996-12-31

    In the recent IPCC report, the role of tropospheric aerosols, stratospheric aerosols, and natural solar variability have also been identified as having sizable effects on climate, both by direct perturbation of the radiative balance and indirectly by changing ozone. Although the effect of changing CO{sub 2} is by far the dominant factor on a century time scale, the effects from the other identified factors are important on a decade time scale. It is important to understand the mechanisms that relate these changes to climatic responses. Developing appropriate numerical models with the capability to simulate these mechanisms will enable one to correctly interpret the observed climate changes that have occurred to data, as well as predict future changes in climate. It is presently impractical to run comprehensive 3-D general circulation model simulations of the interactions between atmospheric chemistry and the rest of the climate system on time scales of decades to centuries. Thus, 2-D models and other lower resolution models play an essential role in understanding the complex interactions of the integrated climate system.

  4. New Development of the Online Integrated Climate-Chemistry model framwork (RegCM-CHEM4)

    NASA Astrophysics Data System (ADS)

    Zakey, A. S.; Shalaby, A. K.; Solmon, F.; Giorgi, F.; Tawfik, A. B.; Steiner, A. L.; Baklanov, A.

    2012-04-01

    The RegCM-CHEM4 is a new online integrated climate-chemistry model based on the regional climate model (RegCM4). The RegCM4 developed at the Abdus Salam International Centre for Theoretical Physics (ICTP), is a hydrostatic, sigma coordinate model. Tropospheric gas-phase chemistry is integrated into the climate model using the condensed version of the Carbon Bond Mechanism CBM-Z with lumped species that represent broad categories of organics based on carbon bond structure. The computationally rapid radical balance method RBM is coupled as a chemical solver to the gas-phase mechanism. Photolysis rates are determined as a function of meteorological and chemical inputs and interpolated from an array of pre-determined values based on the Tropospheric Ultraviolet-Visible Model (TUV) with cloud cover corrections. Cloud optical depths and cloud altitudes from RegCM-CHEM4 are used in the photolysis calculations, thereby directly coupling the photolysis rates and chemical reactions to meteorological conditions at each model time step. In this study, we evaluate the model over Europe for two different time scales: (1) an event-based analysis of the ozone episode associated with the heat wave of August 2003 and (2) a climatological analysis of a six-year simulation (2000-2005). For the episode analysis, model simulations show a good agreement with the European Monitoring and Evaluation Program (EMEP) observations of hourly ozone over different regions in Europe and capture ozone concentrations during and after the summer 2003 heat wave event. Analysis of the full six years of simulation indicates that the coupled chemistry-climate model can reproduce the seasonal cycle of ozone, with an overestimation of ozone in the non-event years of 5-15 ppb depending on the geographic region. Overall, the ozone and ozone precursor evaluation shows the feasibility of using RegCM-CHEM4 for decadal-length simulations of chemistry-climate interactions.

  5. Impact of Aircraft Nox Emissions Simulated With A Coupled Climate-chemistry Model and Sensitivities To Climate-chemistry Feedback, Lightning and Model Resolution

    NASA Astrophysics Data System (ADS)

    Grewe, V.; Dameris, M.; Fichter, C.; Sausen, R.

    The fully coupled climate-chemistry model is applied to investigate the effect of air- craft NOx emissions on the chemical composition of the atmosphere for the time pe- riods 1990 and 2015. The model results show contributions of the aircraft NOx emis- sions to the NOx concentration of 30% and 50% and to the ozone concentration of 3% and 8% in 1990 and 2015, respectively. The pattern of the response will be inter- pretated by using a Lagrangian approach. Additional simulations will be presented to show the sensitivity of the results to the way the chemistry is coupled to the calcu- lation of the meteorology, the description of the lightning NOx emissions, the model resolution, the model domain, and the flight altitude.

  6. Biodiversity: Interacting global change drivers

    NASA Astrophysics Data System (ADS)

    Settele, Josef; Wiemers, Martin

    2015-10-01

    Climate change impacts on species do not occur in isolation. Now research on drought-sensitive British butterflies uses citizen science to attribute the drivers of population changes and shows landscape management to be a key part of the solution.

  7. Education, Interaction, and Social Change.

    ERIC Educational Resources Information Center

    Hodgkinson, Harold L.

    This book examines the interaction of education and other elements in our culture. The social system of education is seen as similar to that of such other formal social institutions as business. Moreover, an understanding of the role and function of education can be achieved through an application of social science theory and research findings.…

  8. Global Climate Change Interaction Web.

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.

    1998-01-01

    Students investigate the effects of global climate change on life in the Great Lakes region in this activity. Teams working together construct as many links as possible for such factors as rainfall, lake water, evaporation, skiing, zebra mussels, wetlands, shipping, walleye, toxic chemicals, coastal homes, and population. (PVD)

  9. Conceptual Acquisition and Change through Social Interaction.

    ERIC Educational Resources Information Center

    Kobayashi, Yoshikazu

    1994-01-01

    Examines the role of social interaction as a facilitator of learning in general and conceptual change in particular. Three conditions are proposed as necessary for social interaction to facilitate knowledge construction--horizontal information, comparable domain knowledge, and availability of cognitive tools. Suggests that these conditions assure…

  10. Plant-plant interactions and environmental change.

    PubMed

    Brooker, Rob W

    2006-01-01

    Natural systems are being subjected to unprecedented rates of change and unique pressures from a combination of anthropogenic environmental change drivers. Plant-plant interactions are an important part of the mechanisms governing the response of plant species and communities to these drivers. For example, competition plays a central role in mediating the impacts of atmospheric nitrogen deposition, increased atmospheric carbon dioxide concentrations, climate change and invasive nonnative species. Other plant-plant interaction processes are also being recognized as important factors in determining the impacts of environmental change, including facilitation and evolutionary processes associated with plant-plant interactions. However, plant-plant interactions are not the only factors determining the response of species and communities to environmental change drivers - their activity must be placed within the context of the wide range of factors that regulate species, communities and ecosystems. A major research challenge is to understand when plant-plant interactions play a key role in regulating the impact of environmental change drivers, and the type of role that plant-plant interactions play. Although this is a considerable challenge, some areas of current research may provide the starting point to achieving these goals, and should be pursued through large-scale, integrated, multisite experiments. PMID:16866935

  11. Technical Note: On the Parallelization of a Global Climate-Chemistry Modeling System

    SciTech Connect

    Lee, Peter S.; Zaveri, Rahul A.; Easter, Richard C.; Peters, Leonard K.

    1999-02-01

    Coupled climate-chemistry simulations are computationally intensive owing to the spatial and temporal scope of the problem. In global chemistry models, the time integrations encountered in the chemistry and aerosol modules usually comprise the major CPU consumption. Parallelization of these segments of the code can contribute to multifold CPU speed-ups with minimal modification of the original serial code. This technical note presents a single program-multiple data (SPMD) strategy applied to the time-split chemistry modules of a coupled climate--global tropospheric chemistry model. Latitudinal domain decomposition is adopted along with a dynamic load-balancing technique that uses the previous time-step's load/latitude estimates for distributing the latitude bands amongst the processors. The coupled model is manually parallelized using the Message Passing Interface standard (MPI) on a distributed memory platform (IBM-SP2). Load-balancing efficiencies and the associated MPI overheads are discussed. Overall speed-ups and efficiencies are also calculated for a series of runs employing up to eight processors.

  12. Responding to Climate Change Interactive Course

    NASA Astrophysics Data System (ADS)

    Pfirman, S. L.; Matter, J. M.; Callahan, P.; Schlosser, P.

    2011-12-01

    While many institutions now have courses that teach climate from an earth or biological systems perspective, it is more challenging to address how to respond to climate change. Implementing adaptation and mitigation measures requires an interdisciplinary approach of involving stakeholders, identifying needs, resolving conflicts and taking action at levels ranging from local, to national and global. Through the upper level undergraduate course "Responding to Climate Change" taught at Barnard College and Columbia University, students engage in a variety of hands-on activities that help them navigate potential options. Activities include games, role play, case studies, scenario development, spatial planning, exploration of analogies, and conflict resolution exercises. Evaluation indicates that this interactive approach empowers students with scientific and technical knowledge, an understanding of how to deal with complexity, and optimism in their capacity to problem solve.

  13. Changes in interacting species with disturbance

    NASA Astrophysics Data System (ADS)

    Cole, Glen F.

    1987-03-01

    Human-influenced changes in the diversity and abundance of native wildlife in a southern boreal forest area, which became a national park in 1975, are used to develop working hypotheses for predicting and subsequently measuring the effects of disturbance or restoration programs on groups of interacting species. Changes from presettlement conditions began with early 1900 hunting, which eliminated woodland caribou ( Rangifer tarandus) and elk ( Cervus elaphus), and reduced moose ( Alces alces) to the low numbers which still persist. Increases in white-tailed deer ( Odocoileus virginianus), as these other cervid species became less abundant or absent, provided enough alternative food to sustain the system's carnivores until plant succession on previously burned or logged areas also caused deer to decline. With increased competition for reduced food, carnivore species also became less abundant or absent and overexploited some prey populations. The abilities of interacting species to maintain dynamically stable populations or persist varied with their different capacities to compensate for increased exploitation or competition. These relationships suggested a possible solution to the problem of predicting the stability of populations in disturbed systems. For the 1976 1985 period, a hypothesis that the increased protection of wildlife from exploitation in a national park would restore a more diverse, abundant, and productive fauna had to be rejected.

  14. Flavor changing supersymmetry interactions in a supernova

    NASA Astrophysics Data System (ADS)

    Amanik, Philip S.; Fuller, George M.; Grinstein, Benjamin

    2005-09-01

    We consider for the first time flavor changing neutral currents (FCNC's) in the infall stage of stellar collapse. We take as an example R-Parity violating interactions of the minimal standard supersymmetric model involving neutrinos and quarks. However, our considerations extend to other kinds of flavor changing neutrino reactions as well. We examine non-forward neutrino scattering processes on heavy nuclei and free nucleons in the supernova core. This investigation has led to four principal original discoveries/products: (1) first calculation of neutrino flavor changing cross sections for spin 1/2 (e.g., free nucleon) and spin 0 nuclear targets; (2) discovery of nuclear mass number squared ( A2) coherent amplification of neutrino-quark FCNC's; (3) analysis of FCNC-induced alteration of electron capture and weak/nuclear equilibrium in the collapsing core; and (4) generalization of the calculated cross sections (mentioned in 1) for the case of hot heavy nuclei to be used in collapse/supernova and neutrino transport simulations. The scattering processes that we consider allow electron neutrinos to change flavor during core collapse, thereby opening holes in the ν e sea, which allows electron capture to proceed and results in a lower core electron fraction Ye. A lower Ye implies a lower homologous core mass, a lower shock energy, and a greater nuclear photo-disintegration burden for the shock. In addition, unlike the standard supernova model, the core now could have net muon and/or tau lepton numbers. These effects could be significant even for supersymmetric couplings below current experimental bounds.

  15. Predicting biotic interactions and their variability in a changing environment.

    PubMed

    Kadowaki, Kohmei; Barbera, Claire G; Godsoe, William; Delsuc, Frédéric; Mouquet, Nicolas

    2016-05-01

    Global environmental change is altering the patterns of biodiversity worldwide. Observation and theory suggest that species' distributions and abundances depend on a suite of processes, notably abiotic filtering and biotic interactions, both of which are constrained by species' phylogenetic history. Models predicting species distribution have historically mostly considered abiotic filtering and are only starting to integrate biotic interaction. However, using information on present interactions to forecast the future of biodiversity supposes that biotic interactions will not change when species are confronted with new environments. Using bacterial microcosms, we illustrate how biotic interactions can vary along an environmental gradient and how this variability can depend on the phylogenetic distance between interacting species. PMID:27220858

  16. Ocean-Atmosphere Interaction in Climate Changes

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy

    1999-01-01

    The diagram, which attests the El Nino teleconnection observed by the NASA Scatterometer (NSCAT) in 1997, is an example of the results of our research in air-sea interaction - the core component of our three-part contribution to the Climate Variability Program. We have established an interplay among scientific research, which turns spacebased data into knowledge, a push in instrument technology, which improves observations of climate variability, and an information system, which produces and disseminates new data to support our scientific research. Timothy Liu led the proposal for advanced technology, in response to the NASA Post-2002 Request for Information. The sensor was identified as a possible mission for continuous ocean surface wind measurement at higher spatial resolution, and with the unique capability to measure ocean surface salinity. He is participating in the Instrument Incubator Program to improve the antenna technology, and is initiating a study to integrate the concept on Japanese missions. He and his collaborators have set up a system to produce and disseminate high level (gridded) ocean surface wind/stress data from NSCAT and European missions. The data system is being expanded to produce real-time gridded ocean surface winds from Quikscat, and precipitation and evaporation from the Tropical Rain Measuring Mission. It will form the basis for a spacebased data analysis system which will include momentum, heat and water fluxes. The study on 1997 El Nino teleconnection illustrates our interdisciplinary and multisensor approach to study climate variability. The diagram shows that the collapse of trade wind and the westerly wind anomalies in the central equatorial Pacific led to the equatorial ocean warming. The equatorial wind anomalies are connected to the anomalous cyclonic wind pattern in the northeast Pacific. The anomalous warming along the west coast of the United States is the result of the movement of the pre-existing warm sea surface

  17. Use of the HadGEM2 climate-chemistry model to investigate interannual variability in methane sources

    NASA Astrophysics Data System (ADS)

    Hayman, Garry; O'Connor, Fiona; Clark, Douglas; Huntingford, Chris; Gedney, Nicola

    2013-04-01

    The global mean atmospheric concentration of methane (CH4) has more than doubled during the industrial era [1] and now constitutes ? 20% of the anthropogenic climate forcing by greenhouse gases [2]. The globally-averaged CH4 growth rate, derived from surface measurements, has fallen significantly from a high of 16 ppb yr-1 in the late 1970s/early 1980s and was close to zero between 1999 and 2006 [1]. This overall period of declining or low growth was however interspersed with years of positive growth-rate anomalies (e.g., in 1991-1992, 1998-1999 and 2002-2003). Since 2007, renewed growth has been evident [1, 3], with the largest increases observed over polar northern latitudes and the Southern Hemisphere in 2007 and in the tropics in 2008. The observed inter-annual variability in atmospheric methane concentrations and the associated changes in growth rates have variously been attributed to changes in different methane sources and sinks [1, 4]. In this paper, we report results from runs of the HadGEM2 climate-chemistry model [5] using year- and month-specific emission datasets. The HadGEM2 model includes the comprehensive atmospheric chemistry and aerosol package, the UK Chemistry Aerosol community model (UKCA, http://www.ukca.ac.uk/wiki/index.php). The Standard Tropospheric Chemistry scheme was selected for this work. This chemistry scheme simulates the Ox, HOx and NOx chemical cycles and the oxidation of CO, methane, ethane and propane. Year- and month-specific emission datasets were generated for the period from 1997 to 2009 for the emitted species in the chemistry scheme (CH4, CO, NOx, HCHO, C2H6, C3H8, CH3CHO, CH3CHOCH3). The approach adopted varied depending on the source sector: Anthropogenic: The emissions from anthropogenic sources were based on decadal-averaged emission inventories compiled by [6] for the Coupled Carbon Cycle Climate Model Intercomparison Project (C4MIP). These were then used to derive year-specific emission datasets by scaling the

  18. Use of the HadGEM2 climate-chemistry model to investigate interannual variability in methane sources

    NASA Astrophysics Data System (ADS)

    Hayman, Garry; O'Connor, Fiona; Clark, Douglas; Huntingford, Chris; Gedney, Nicola

    2013-04-01

    The global mean atmospheric concentration of methane (CH4) has more than doubled during the industrial era [1] and now constitutes ? 20% of the anthropogenic climate forcing by greenhouse gases [2]. The globally-averaged CH4 growth rate, derived from surface measurements, has fallen significantly from a high of 16 ppb yr-1 in the late 1970s/early 1980s and was close to zero between 1999 and 2006 [1]. This overall period of declining or low growth was however interspersed with years of positive growth-rate anomalies (e.g., in 1991-1992, 1998-1999 and 2002-2003). Since 2007, renewed growth has been evident [1, 3], with the largest increases observed over polar northern latitudes and the Southern Hemisphere in 2007 and in the tropics in 2008. The observed inter-annual variability in atmospheric methane concentrations and the associated changes in growth rates have variously been attributed to changes in different methane sources and sinks [1, 4]. In this paper, we report results from runs of the HadGEM2 climate-chemistry model [5] using year- and month-specific emission datasets. The HadGEM2 model includes the comprehensive atmospheric chemistry and aerosol package, the UK Chemistry Aerosol community model (UKCA, http://www.ukca.ac.uk/wiki/index.php). The Standard Tropospheric Chemistry scheme was selected for this work. This chemistry scheme simulates the Ox, HOx and NOx chemical cycles and the oxidation of CO, methane, ethane and propane. Year- and month-specific emission datasets were generated for the period from 1997 to 2009 for the emitted species in the chemistry scheme (CH4, CO, NOx, HCHO, C2H6, C3H8, CH3CHO, CH3CHOCH3). The approach adopted varied depending on the source sector: Anthropogenic: The emissions from anthropogenic sources were based on decadal-averaged emission inventories compiled by [6] for the Coupled Carbon Cycle Climate Model Intercomparison Project (C4MIP). These were then used to derive year-specific emission datasets by scaling the

  19. Floods and climate change: interactions and impacts.

    PubMed

    Bronstert, Axel

    2003-06-01

    Whether the floods experienced during the last decade in Germany and in other European countries are triggered or worsened by human activities has been the subject of a great deal of debate. Possible anthropogenic activities leading to increased flood risk include river regulation measures, intensified land use and forestry, and emissions of greenhouse gases causing a change in the global climate. This article discusses the latter by reviewing the existing knowledge on the subject. First, the relevance, capabilities, and limitations of climate models for the simulation and analysis of flood risk under aspects of the anthropogenic climate change are described. Special consideration is given here to differences between the "typical" spatial scale of climate models and hydrological flood models. Second, observations of trends in climate variables relevant for river flooding issues are summarized. Special emphasis is put on the Rhine and other German catchment areas. Third, the possibilities of modeling the different parts of the "cascade of flood risk" are summarized, introducing the special features of meteorological, hydrological, and river hydraulic models. PMID:12836847

  20. Coevolution and the Effects of Climate Change on Interacting Species

    PubMed Central

    Northfield, Tobin D.; Ives, Anthony R.

    2013-01-01

    Background Recent studies suggest that environmental changes may tip the balance between interacting species, leading to the extinction of one or more species. While it is recognized that evolution will play a role in determining how environmental changes directly affect species, the interactions among species force us to consider the coevolutionary responses of species to environmental changes. Methodology/Principle Findings We use simple models of competition, predation, and mutualism to organize and synthesize the ways coevolution modifies species interactions when climatic changes favor one species over another. In cases where species have conflicting interests (i.e., selection for increased interspecific interaction strength on one species is detrimental to the other), we show that coevolution reduces the effects of climate change, leading to smaller changes in abundances and reduced chances of extinction. Conversely, when species have nonconflicting interests (i.e., selection for increased interspecific interaction strength on one species benefits the other), coevolution increases the effects of climate change. Conclusions/Significance Coevolution sets up feedback loops that either dampen or amplify the effect of environmental change on species abundances depending on whether coevolution has conflicting or nonconflicting effects on species interactions. Thus, gaining a better understanding of the coevolutionary processes between interacting species is critical for understanding how communities respond to a changing climate. We suggest experimental methods to determine which types of coevolution (conflicting or nonconflicting) drive species interactions, which should lead to better understanding of the effects of coevolution on species adaptation. Conducting these experiments across environmental gradients will test our predictions of the effects of environmental change and coevolution on ecological communities. PMID:24167443

  1. Modelling refractive index changes due to molecular interactions

    NASA Astrophysics Data System (ADS)

    Varma, Manoj

    2016-03-01

    There are a large number of sensing techniques which use optical changes to monitor interactions between molecules. In the absence of fluorophores or other labels, the basic signal transduction mechanism relies on refractive index changes arising from the interactions of the molecules involved. A quantitative model incorporating molecular transport, reaction kinetics and optical mixing is presented which reveals important insights concerning the optimal detection of molecular interactions optically. Although conceptually simple, a comprehensive model such as this has not been reported anywhere. Specifically, we investigate the pros and cons of detecting molecular interactions in free solution relative to detecting molecular interactions on surfaces using surface bound receptor molecules such as antibodies. The model reveals that the refractive index change produced in surface based sensors is 2-3 orders of magnitude higher than that from interactions in free solution. On the other hand, the model also reveals that it is indeed possible to distinguish specific molecular interactions from non-specific ones based on free-solution bulk refractometry without any washing step necessary in surface based sensors. However, the refractive index change for free solution interactions predicted by the model is smaller than 10-7 RIU, even for large proteins such as IgG in sufficiently high concentrations. This value is smaller than the typical 10-6 RIU detection limit of most state of the art optical sensing techniques therefore requiring techniques with substantially higher index sensitivity such as Back Scattering Interferometry.

  2. Revisiting trough interactions and tropical cyclone intensity change

    NASA Astrophysics Data System (ADS)

    Peirano, C. M.; Corbosiero, K. L.; Tang, B. H.

    2016-05-01

    An updated climatology of Atlantic basin tropical cyclone (TC) intensity change in the presence of upper tropospheric trough forcing is presented. To control for changes in the background thermodynamic environment, a methodology that normalizes intensity change by the potential intensity of the TC is used to more narrowly focus on the effect of troughs compared to previous studies. Relative to the full sample of Atlantic TCs, troughs are a negative influence on intensification: trough interaction cases are 4% less likely to intensify and 5% more likely to weaken. Troughs are especially detrimental compared to TCs without trough forcing: trough interaction cases are 14% less likely to intensify and 13% more likely to weaken. Additionally, eddy flux convergence of angular momentum, previously shown to positively affect TC intensity change, is shown to be a weak predictor of intensity change compared to vertical wind shear, which is enhanced during a trough interaction.

  3. An effect of change in patient status on marital interaction.

    PubMed

    Roman, M; Bauman, G; Borello, J; Meltzer, B; Ehrenberg, D B

    1976-06-01

    In the treatment of couples and families, even more so than of individuals, therapists invariably are forced to face the problem of assessment of change in the marital or family "system." The purpose of the present study was to investigate changes in marital interaction for a special population, that is, in which one member of each married pair had been, but was no longer, a hospitalized psychiatric patient. The primary question we addressed was whether changes in marital interaction could be amply detected and whether these changes could be attributed to the particular role shift that had occurred in one spouse--from "patient" to "nonpatient." Utilizing a technique called Interaction Testing, which the senior authors devised in 1960, we found that such alterations in marital interaction do indeed arise when one member of the couple moves out of a patient role and that our instrument is useful in elucidating the nature of such effects. In addition, it can be expected that a study of this kind will be of theoretical and methodological value in dealing with the general issues of problem-solving interaction in couples and families. The clinical aspect of the study may also be expected to stimulate useful thinking regarding family theapy in hospital settings, patient management, and aftercare. PMID:1026444

  4. Interactive Effects of Nitrogen and Climate Change on Biodiversity

    NASA Astrophysics Data System (ADS)

    Porter, E. M.; Bowman, W. D.; Clark, C. M.; Compton, J. E.; Pardo, L. H.; Soong, J.

    2011-12-01

    Biodiversity has been described as the diversity of life on earth within species, between species and in ecosystems. Biodiversity contributes to regulating ecosystem services like climate, flood, disease, and water quality regulation. Biodiversity also supports and sustains ecosystem services that provide material goods like food, fiber, fuel, timber and water, and to non-material benefits like educational, recreational, spiritual, and aesthetic ecosystem services. The Millennium Ecosystem Assessment estimated that the rate of biodiversity loss due to human activity in the last 50 years has been more rapid than at any other time in human history, and that many of the drivers of biodiversity loss are increasing. The strongest drivers of biodiversity loss include habitat loss, overexploitation, invasive species, climate change, and pollution, including pollution from reactive nitrogen. Of these stressors, climate change and reactive nitrogen from anthropogenic activities are causing some of the most rapid changes. Climate change is causing warming trends that result in consistent patterns of poleward and elevational range shifts of flora and fauna, causing changes in biodiversity. Warming has also resulted in changes in phenology, particularly the earlier onset of spring events, migration, and lengthening of the growing season, disrupting predator-prey and plant-pollinator interactions. In addition to warming, elevated carbon dioxide by itself can affect biodiversity by influencing plant growth, soil water, tissue stoichiometry, and trophic interactions. Nitrogen enrichment also impacts ecosystems and biodiversity in a variety of ways. Nitrogen enhances plant growth, but has been shown to favor invasive, fast-growing species over native species adapted to low nitrogen conditions. Although there have been a limited number of empirical studies on climate change and nitrogen interactions, inferences can be drawn from observed responses to each stressor by itself. For

  5. Interactive Sectoring and Animation of Global Change Data

    NASA Technical Reports Server (NTRS)

    Meyer, Paul J.; Buillory, Anthony R.; Atkinson, Robert J.; Jedlovec, Gary J.

    1999-01-01

    In order to analyze and share results of global change data sets, scientists require a venue in which to exchange their results. One appropriate medium for these collaborative efforts is the world wide web. Intuitive and efficient user interfaces, and background processes have been developed at the Global Hydrology and Climate Center to interactively view weather satellite, radar, global temperature anomaly, and model output data using the world wide web. These tools combine scripts, Java and C code which allows the user to easily interact with data, to create high resolution sector images, and sectored animation sequences. This paper examines the architecture and interfaces and how they are used for collaborative research.

  6. Change point testing in logistic regression models with interaction term.

    PubMed

    Fong, Youyi; Di, Chongzhi; Permar, Sallie

    2015-04-30

    A threshold effect takes place in situations where the relationship between an outcome variable and a predictor variable changes as the predictor value crosses a certain threshold/change point. Threshold effects are often plausible in a complex biological system, especially in defining immune responses that are protective against infections such as HIV-1, which motivates the current work. We study two hypothesis testing problems in change point models. We first compare three different approaches to obtaining a p-value for the maximum of scores test in a logistic regression model with change point variable as a main effect. Next, we study the testing problem in a logistic regression model with the change point variable both as a main effect and as part of an interaction term. We propose a test based on the maximum of likelihood ratios test statistic and obtain its reference distribution through a Monte Carlo method. We also propose a maximum of weighted scores test that can be more powerful than the maximum of likelihood ratios test when we know the direction of the interaction effect. In simulation studies, we show that the proposed tests have a correct type I error and higher power than several existing methods. We illustrate the application of change point model-based testing methods in a recent study of immune responses that are associated with the risk of mother to child transmission of HIV-1. PMID:25612253

  7. Multivariate Analysis of Conformational Changes Induced by Macromolecular Interactions

    NASA Astrophysics Data System (ADS)

    Mitra, Indranil; Alexov, Emil

    2009-11-01

    Understanding protein-protein binding and associated conformational changes is critical for both understanding thermodynamics of protein interactions and successful drug discovery. Our study focuses on computational analysis of plausible correlations between induced conformational changes and set of biophysical characteristics of interacting monomers. It was done by comparing 3D structures of unbound and bound monomers to calculate the RMSD which is used as measure of the structural changed induced by the binding. We correlate RMSD with volumetric and interfacial charge of the monomers, the amino acid composition, the energy of binding, and type of amino acids at the interface. as predictors. The data set was analyzed with SVM in R & SPSS which is trained on a combination of a new robust evolutionary conservation signal with the monomeric properties to predict the induced RMSD. The goal of this study is to undergo parametric tests and heirchiacal cluster and discriminant multivariate analysis to find key predictors which will be used to develop algorithm to predict the magnitude of conformational changes provided by the structure of interacting monomers. Results indicate that the most promising predictor is the net charge of the monomers, however, other parameters as the type of amino acids at the interface have significant contribution as well.

  8. Qualitative change of character of dispersive interaction with intermolecular distance.

    PubMed

    Haslmayr, Johannes; Renger, Thomas

    2013-07-28

    The dispersive interaction between molecules results from Coulomb-correlated fluctuations of electrons and for large intermolecular distances it can be related to the molecular polarizabilities as in London's theory (F. London, Trans. Faraday Soc. 33, 8-26 (1937)). Here, we investigate the interaction between molecules with anisotropic polarizabilities at arbitrary distances using symmetry adapted perturbation theory, which allows us to analyze the different parts of the intermolecular potential separately. Whereas at large distances, in accordance with London's theory, there is no way to describe the dispersive interaction by a sum over pairwise isotropic atom-centered energy terms, at short distances such a description becomes possible. This surprising result has consequences for the development of molecular mechanics force fields, supports the dispersion energy terms applied in dispersion corrected density functional theory, and indicates that there is a qualitative change in electron correlation with distance. Apparently, at short distances intermolecular electron correlation is less influenced by intramolecular electron delocalization. PMID:23901956

  9. Biotic interactions mediate soil microbial feedbacks to climate change.

    PubMed

    Crowther, Thomas W; Thomas, Stephen M; Maynard, Daniel S; Baldrian, Petr; Covey, Kristofer; Frey, Serita D; van Diepen, Linda T A; Bradford, Mark A

    2015-06-01

    Decomposition of organic material by soil microbes generates an annual global release of 50-75 Pg carbon to the atmosphere, ∼7.5-9 times that of anthropogenic emissions worldwide. This process is sensitive to global change factors, which can drive carbon cycle-climate feedbacks with the potential to enhance atmospheric warming. Although the effects of interacting global change factors on soil microbial activity have been a widespread ecological focus, the regulatory effects of interspecific interactions are rarely considered in climate feedback studies. We explore the potential of soil animals to mediate microbial responses to warming and nitrogen enrichment within a long-term, field-based global change study. The combination of global change factors alleviated the bottom-up limitations on fungal growth, stimulating enzyme production and decomposition rates in the absence of soil animals. However, increased fungal biomass also stimulated consumption rates by soil invertebrates, restoring microbial process rates to levels observed under ambient conditions. Our results support the contemporary theory that top-down control in soil food webs is apparent only in the absence of bottom-up limitation. As such, when global change factors alleviate the bottom-up limitations on microbial activity, top-down control becomes an increasingly important regulatory force with the capacity to dampen the strength of positive carbon cycle-climate feedbacks. PMID:26038557

  10. Biotic interactions mediate soil microbial feedbacks to climate change

    PubMed Central

    Crowther, Thomas W.; Thomas, Stephen M.; Maynard, Daniel S.; Baldrian, Petr; Covey, Kristofer; Frey, Serita D.; van Diepen, Linda T. A.; Bradford, Mark A.

    2015-01-01

    Decomposition of organic material by soil microbes generates an annual global release of 50–75 Pg carbon to the atmosphere, ∼7.5–9 times that of anthropogenic emissions worldwide. This process is sensitive to global change factors, which can drive carbon cycle–climate feedbacks with the potential to enhance atmospheric warming. Although the effects of interacting global change factors on soil microbial activity have been a widespread ecological focus, the regulatory effects of interspecific interactions are rarely considered in climate feedback studies. We explore the potential of soil animals to mediate microbial responses to warming and nitrogen enrichment within a long-term, field-based global change study. The combination of global change factors alleviated the bottom-up limitations on fungal growth, stimulating enzyme production and decomposition rates in the absence of soil animals. However, increased fungal biomass also stimulated consumption rates by soil invertebrates, restoring microbial process rates to levels observed under ambient conditions. Our results support the contemporary theory that top-down control in soil food webs is apparent only in the absence of bottom-up limitation. As such, when global change factors alleviate the bottom-up limitations on microbial activity, top-down control becomes an increasingly important regulatory force with the capacity to dampen the strength of positive carbon cycle–climate feedbacks. PMID:26038557

  11. Audiotactile interaction can change over time in cochlear implant users

    PubMed Central

    Landry, Simon P.; Guillemot, Jean-Paul; Champoux, François

    2014-01-01

    Recent results suggest that audiotactile interactions are disturbed in cochlear implant (CI) users. However, further exploration regarding the factors responsible for such abnormal sensory processing is still required. Considering the temporal nature of a previously used multisensory task, it remains unclear whether any aberrant results were caused by the specificity of the interaction studied or rather if it reflects an overall abnormal interaction. Moreover, although duration of experience with a CI has often been linked with the recovery of auditory functions, its impact on multisensory performance remains uncertain. In the present study, we used the parchment-skin illusion, a robust illustration of sound-biased perception of touch based on changes in auditory frequencies, to investigate the specificities of audiotactile interactions in CI users. Whereas individuals with relatively little experience with the CI performed similarly to the control group, experienced CI users showed a significantly greater illusory percept. The overall results suggest that despite being able to ignore auditory distractors in a temporal audiotactile task, CI users develop to become greatly influenced by auditory input in a spectral audiotactile task. When considered with the existing body of research, these results confirm that normal sensory interaction processing can be compromised in CI users. PMID:24904359

  12. Audiotactile interaction can change over time in cochlear implant users.

    PubMed

    Landry, Simon P; Guillemot, Jean-Paul; Champoux, François

    2014-01-01

    Recent results suggest that audiotactile interactions are disturbed in cochlear implant (CI) users. However, further exploration regarding the factors responsible for such abnormal sensory processing is still required. Considering the temporal nature of a previously used multisensory task, it remains unclear whether any aberrant results were caused by the specificity of the interaction studied or rather if it reflects an overall abnormal interaction. Moreover, although duration of experience with a CI has often been linked with the recovery of auditory functions, its impact on multisensory performance remains uncertain. In the present study, we used the parchment-skin illusion, a robust illustration of sound-biased perception of touch based on changes in auditory frequencies, to investigate the specificities of audiotactile interactions in CI users. Whereas individuals with relatively little experience with the CI performed similarly to the control group, experienced CI users showed a significantly greater illusory percept. The overall results suggest that despite being able to ignore auditory distractors in a temporal audiotactile task, CI users develop to become greatly influenced by auditory input in a spectral audiotactile task. When considered with the existing body of research, these results confirm that normal sensory interaction processing can be compromised in CI users. PMID:24904359

  13. Deforestation changes land-atmosphere interactions across South American biomes

    NASA Astrophysics Data System (ADS)

    Salazar, Alvaro; Katzfey, Jack; Thatcher, Marcus; Syktus, Jozef; Wong, Kenneth; McAlpine, Clive

    2016-04-01

    South American biomes are increasingly affected by land use/land cover change. However, the climatic impacts of this phenomenon are still not well understood. In this paper, we model vegetation-climate interactions with a focus on four main biomes distributed in four key regions: The Atlantic Forest, the Cerrado, the Dry Chaco, and the Chilean Matorral ecosystems. We applied a three member ensemble climate model simulation for the period 1981-2010 (30 years) at 25 km resolution over the focus regions to quantify the changes in the regional climate resulting from historical deforestation. The results of computed modelling experiments show significant changes in surface fluxes, temperature and moisture in all regions. For instance, simulated temperature changes were stronger in the Cerrado and the Chilean Matorral with an increase of between 0.7 and 1.4 °C. Changes in the hydrological cycle revealed high regional variability. The results showed consistent significant decreases in relative humidity and soil moisture, and increases in potential evapotranspiration across biomes, yet without conclusive changes in precipitation. These impacts were more significant during the dry season, which resulted to be drier and warmer after deforestation.

  14. Mantle plume interaction with an endothermic phase change

    NASA Technical Reports Server (NTRS)

    Schubert, Gerald; Anderson, Charles; Goldman, Peggy

    1995-01-01

    High spatial resolution numerical simulations of mantle plumes impinging from below on the endothermic phase change at 660-km depth are used to investigate the effects of latent heat release on the plume-phase change interaction. Both axisymmetric and planar upflows are considered, and the strong temperature dependence of mantle viscosity is taken into account. For plume strengths considered, a Clapeyron slope of -4 MPa/K prevents plume penetration of the phase change. Plumes readily penetrate the phase change for a Clapeyron slope of -2 MPa/K and arrive in the upper mantle considerably hotter than if they had not traversed the phase change. For the same amount of thermal drive, i.e., the same excess basal temperature, axisymmetric plumes are hotter upon reaching the upper mantle than are planar upwellings. Heating of plumes by their passage through the spinel-perovskite endothermic phase change can have important consequences for the ability of the plume to thermally thin the lithosphere and cause melting and volcanism.

  15. Changing intensity of interaction can resolve prisoner's dilemmas

    NASA Astrophysics Data System (ADS)

    Li, Jiaqi; Zhang, Chunyan; Sun, Qinglin; Chen, Zengqiang; Zhang, Jianlei

    2016-03-01

    We put forward a computational model which mainly focuses on the effect of changing the intensity of interaction between individuals to study the evolutionary prisoner's dilemma game in social networks. In this model, an individual will unilaterally increase the intensity of interaction from it to some of its neighbors in case it is satisfied with the current income which it obtains from the neighbor; conversely, the individual will unilaterally reduce the intensity of interaction from it to its neighbor. We show that this simple evolutionary rule can effectively shift the survival barrier of cooperators and drastically facilitate the emergence of cooperation. Interestingly, for a fixed temptation to defect, there exists the smallest increment of intensity of interaction, resulting in a plateau of high cooperation level due to the positive feedback mechanism. Furthermore, we find good agreement between simulation results and theoretical predictions obtained from an extended pair-approximation method. Meanwhile, we illustrate the dynamical evolution of cooperators on the network, and investigate the impact of noise during the strategy updates.

  16. Interactive Sectoring and Animation of Global Change Data

    NASA Technical Reports Server (NTRS)

    Meyer, Paul J.; Guillory, Anthony; Atkinson, R. J.; Jedlovec, Gary J.

    1999-01-01

    In order to analyze and share results of global change climate data sets, scientists require a venue in which to exchange their results. The perfect medium for these collaborative efforts is the world wide web. Intuitive and efficient user interfaces, and background processes were developed at the Global Hydrology and Climate Center to interactively view weather satellite, radar, global temperature anomaly, and model output data using the world wide web. These tools combine scripts, Java, and C code, which allows the end user to easily interact with data, to create high resolution sector images, and sectored animation sequences. This paper examines the architecture and interfaces which were designed at the Global Hydrology and Climate Center and how they are used for collaborative research.

  17. Shock wave interaction with an abrupt area change

    NASA Technical Reports Server (NTRS)

    Salas, Manuel D.

    1991-01-01

    The wave patterns that occur when a shock wave interacts with an abrupt area changed are analyzed in terms of the incident shock wave Mach number and area-jump ratio. The solutions predicted by a semi-similar models are in good agreement with those obtained numerically from the quasi-one-dimensional time-dependent Euler equations. The entropy production for the wave system is defined and the principle of minimum entropy production is used to resolve a nonuniqueness problem of the self-similar model.

  18. Binding interaction between rice glutelin and amylose: Hydrophobic interaction and conformational changes.

    PubMed

    Xu, Xingfeng; Liu, Wei; Zhong, Junzhen; Luo, Liping; Liu, Chengmei; Luo, Shunjing; Chen, Lin

    2015-11-01

    The interaction of rice glutelin (RG) with amylose was characterized by spectroscopic and molecular docking studies. The intrinsic fluorescence of RG increased upon the addition of amylose. The binding sites, binding constant and thermodynamic features indicated that binding process was spontaneous and the main driving force of the interaction was hydrophobic interaction. The surface hydrophobicity of RG decreased with increasing amount of amylose. Furthermore, synchronous fluorescence and circular dichroism (CD) spectra provided data concerning conformational and micro-environmental changes of RG. With the concentration of amylose increasing, the polarity around the tyrosine residues increased while the hydrophobicity decreased. Alteration of protein conformation was observed with increasing of α-helix and reducing of β-sheet. Finally, a visual representation of two binding sites located in the amorphous area of RG was presented by molecular modeling studies. PMID:26416238

  19. Climate change exacerbates interspecific interactions in sympatric coastal fishes.

    PubMed

    Milazzo, Marco; Mirto, Simone; Domenici, Paolo; Gristina, Michele

    2013-03-01

    Biological responses to warming are presently based on the assumption that species will remain within their bioclimatic envelope as environmental conditions change. As a result, changes in the relative abundance of several marine species have been documented over the last decades. This suggests that warming may drive novel interspecific interactions to occur (i.e. invasive vs. native species) or may intensify the strength of pre-existing ones (i.e. warm vs. cold adapted). For mobile species, habitat relocation is a viable solution to track tolerable conditions and reduce competitive costs, resulting in 'winner' species dominating the best quality habitat at the expense of 'loser' species. Here, we focus on the importance of warming in exacerbating interspecific interactions between two sympatric fishes. We assessed the relocation response of the cool-water fish Coris julis (a potential 'loser' species in warming scenarios) at increasing relative dominance of the warm-water fish Thalassoma pavo (a 'winner' species). These wrasses are widespread in the Mediterranean nearshore waters. C. julis tolerates cooler waters and is found throughout the basin. T. pavo is common along southern coasts, although the species range is expanding northwards as the Mediterranean warms. We surveyed habitat patterns along a thermo-latitudinal gradient in the Western Mediterranean Sea and manipulated seawater temperature under two scenarios (present day vs. projected) in outdoor arenas. Our results show that the cool-water species relocates to a less-preferred seagrass habitat and undergoes lower behavioural performance in warmer environments, provided the relative dominance of its warm-water antagonist is high. The results suggest that expected warming will act synergistically with increased relative dominance of a warm-water species to cause a cool-water fish to relocate in a less-preferred habitat within the same thermal environment. Our study highlights the complexity of climate

  20. Noise pollution changes avian communities and species interactions.

    PubMed

    Francis, Clinton D; Ortega, Catherine P; Cruz, Alexander

    2009-08-25

    Humans have drastically changed much of the world's acoustic background with anthropogenic sounds that are markedly different in pitch and amplitude than sounds in most natural habitats. This novel acoustic background may be detrimental for many species, particularly birds. We evaluated conservation concerns that noise limits bird distributions and reduces nesting success via a natural experiment to isolate the effects of noise from confounding stimuli and to control for the effect of noise on observer detection biases. We show that noise alone reduces nesting species richness and leads to different avian communities. Contrary to expectations, noise indirectly facilitates reproductive success of individuals nesting in noisy areas as a result of the disruption of predator-prey interactions. The higher reproductive success for birds within noisy habitats may be a previously unrecognized factor contributing to the success of urban-adapted species and the loss of birds less tolerant of noise. Additionally, our findings suggest that noise can have cascading consequences for communities through altered species interactions. Given that noise pollution is becoming ubiquitous throughout much of the world, knowledge of species-specific responses to noise and the cumulative effects of these novel acoustics may be crucial to understanding and managing human-altered landscapes. PMID:19631542

  1. Does cadmium pollution change trophic interactions in rockpool food webs?

    SciTech Connect

    Koivisto, S.; Arner, M.; Kautsky, N.

    1997-06-01

    The authors studied the regulation of phytoplankton and zooplankton biomass in rockpool food webs under chronic cadmium pollution. Experimental food webs with two and three trophic levels were composed of phytoplankton, small-bodied zooplankton (Chydorus sphaericus, Cyclops sp., and rotifers), Daphnia magna, and Notonecta sp., a zooplanktivorous predator. Every food web received a control and cadmium treatment allowing a separate study of cadmium and predation effects. After a 3-week stabilization period, cadmium and Notonecta were added and changes in primary productivity, chlorophyll, zooplankton species composition, and biomass were followed during 8 weeks. The results showed that phytoplankton and Daphnia were consumer regulated in both control and cadmium treatments, although resource availability ultimately determined the biomass at each trophic level. Daphnia was the only zooplankton species that reduced phytoplankton and also the only species that was eliminated by Notonecta predation. Notonecta had an indirect positive impact on phytoplankton biomass that increased after the extinction of Daphnia. Cadmium significantly reduced phytoplankton and Daphnia but did not change the trophic interactions between them, i.e., Daphnia and chlorophyll were significantly negatively correlated both in the control and cadmium treatments. Cadmium did not affect the relationship between Daphnia and Notonecta.

  2. Laser-tissue photothermal interaction and tissue temperature change

    NASA Astrophysics Data System (ADS)

    Ives, Andrea K.; Chen, Wei R.; Jassemnejad, Baha; Bartels, Kenneth E.; Liu, Hong; Nordquist, John A.; Nordquist, Robert E.

    2000-06-01

    Responses of tissue to laser stimulation are crucial in both disease diagnostics and treatment. In general, when tissue absorbs laser energy photothermal interaction occurs. The most important signature of the photothermal reaction is the tissue temperature change during and after the laser irradiation. Experimentally, the tissue reaction to laser irradiation can be measured by numerous methods including direct temperature measurement and measurement of perfusion change. In this study, a multiple-channel temperature probe was used to measure tissue temperature change during irradiation of lasers with different wavelengths at different power settings. Tissue temperature in chicken breast tissue as well as skin and breast tumor of rats was measured during irradiation of an 805-nm diode laser. The vertical profiles of temperature were obtained using simultaneous measurement at several different locations. The absorption of laser energy by tissue was enhanced by injecting laser-absorbing dye into the tissue. A Nd:YAG laser of 1064-nm wavelength was also used to irradiate turkey breast tissue. Our results showed that both laser penetration ability and photothermal reaction depended on the wavelength of lasers. In the case of 805-nm laser, the temperature increased rapidly only in the region close to the laser source and the thermal equilibrium could be reached within a short time period. The laser absorbing dye drastically enhanced the thermal reaction, resulting in approximately 4-fold temperature increase. On the contrary, the laser beam with 1064-nm wavelength penetrated deeply into tissue and the tissue temperature continued increasing even after a 10-minute laser irradiation.

  3. Innovative Interactive Visitor Experiences Focused on Climate Change

    NASA Astrophysics Data System (ADS)

    Lettvin, E. E.

    2011-12-01

    Pacific Science Center has adopted a multi-pronged approach to introduce visitors to the concepts of climate change and linkages to human behavior in an informal science education setting. We leverage key fixed exhibit assets derived from collaborations with NOAA: Science on a Sphere and an exhibit kiosk showcasing local CO2 measurements that are adjacent on our exhibit floor. NOAA PMEL Scientists deployed a sensor at the top of the Space Needle that measures variability in atmospheric CO2 over Seattle; the kiosk showcases these near-real-time, daily, weekly and monthly measurements as well as similar observations from a NOAA buoy near Aberdeen, Washington. Displays of these data enable visitors to see first-hand varying CO2 levels in urban and remote marine environments as well as seasonal cycling. It also reveals quantifiable increases in CO2 levels over a relatively short time (~5 years). Trained interpreters help visitors understand linkages between personal behavior and corresponding CO2 footprints. Interpreters discuss connections between local and regional CO2 measurements displayed on the kiosk, and global Sphere datasets including NOAA Carbon Tracker, changing arctic sea ice coverage and sea level rise projections. Portable Discovery Carts, consisting of props and interactive, hands-on activities provide a platform for facilitated interpretation on a series of topics. We have developed two climate focused carts: 'Sinks and Sources' that examines materials and activities that produce and absorb carbon, and 'Ocean Acidification' that shows how absorption of atmospheric CO2 is changing ocean composition and its habitability for marine life. These carts can be deployed anywhere on the exhibit floor but are primarily used adjacent to the Sphere and the kiosk, making it possible to have a range of conversations about global and local CO2 levels, linkages to individual and collective behaviour and associated implications. Additional collaborations with members of

  4. Changing shape of elastic shells via electrostatic interactions

    NASA Astrophysics Data System (ADS)

    Jadhao, Vikram; Thomas, Creighton; Olvera de La Cruz, Monica

    2014-03-01

    Shape plays a key role in the design of synthetic structures such as biomimetic red blood cells, metallic nanocontainers and colloidal building blocks for self-assembly. It is therefore crucial to enhance our current capabilities to synthesize membranes of desired shapes with precision and provide a simple procedure to induce shape modifications. We show that Coulomb interactions can be used as a tool for designing and manipulating shapes of soft elastic shells at the nanoscale. We investigate the minimal-energy conformations of charged, elastic nanoshells subject to the constraint of fixed total volume for a wide range of electrostatic and elastic parameters. We find that the shape of the shell changes when we decrease the electrolyte concentration in the surrounding environment or increase the total charge on the shell surface. We obtain a variety of smooth shapes that include ellipsoids, discs, and bowls. A discussion on the possible origins of these shapes and related procedures to induce shape deformations is also provided. We thank U.S. Department of Energy Award DEFG02-08ER46539 and the Office of the Director of Defense Research and Engineering (DDR&E) and the Air Force Office of Scientific Research (AFOSR) Award No. FA9550-10-1-0167 for financial support.

  5. Volatile interaction between undamaged plants affects tritrophic interactions through changed plant volatile emission.

    PubMed

    Vucetic, Andja; Dahlin, Iris; Petrovic-Obradovic, Olivera; Glinwood, Robert; Webster, Ben; Ninkovic, Velemir

    2014-01-01

    Volatile interactions between unattacked plants can lead to changes in their volatile emissions. Exposure of potato plants to onion plant volatiles results in increased emission of 2 terpenoids, (E)-nerolidol and TMTT. We investigated whether this is detectable by the ladybird Coccinella septempunctata. The odor of onion-exposed potato was significantly more attractive to ladybirds than that of unexposed potato. Further, a synthetic blend mimicking the volatile profile of onion-exposed potato was more attractive than a blend mimicking that of unexposed potato. When presented individually, TMTT was attractive to ladybirds whereas (E)-nerolidol was repellent. Volatile exchange between unattacked plants and consequent increased attractiveness for ladybirds may be a mechanism that contributes to the increased abundance of natural enemies in complex plant habitats. PMID:25763628

  6. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarado; H. Yasuhara; A. Alajmi; Z. Karpyn

    2002-10-28

    The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (1) developing the direct experimental measurements of fracture aperture and topology using high-resolution x-ray microtomography, (2) modeling of fracture permeability in the presence of asperities and confining stress, and (3) simulation of two-phase fluid flow in a fracture and a layered matrix. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. The distribution of fracture aperture is a difficult issue that we are studying and developing methods of quantification. The difficulties are both numerical and conceptual. Numerically, the three-dimensional data sets include millions, and sometimes, billions of points, and pose a computational challenge. The conceptual difficulties derive from the rough nature of the fracture surfaces, and the heterogeneous nature of the rock matrix. However, the high-resolution obtained by the imaging system provides us a much needed measuring environment on rock samples that are subjected to simultaneous fluid flow and confining stress. Pilot multi-phase experiments have been performed, proving the ability to detect two phases in certain large fractures. The absolute permeability of a fracture depends on the behavior of the asperities that keep it open. A model is being developed that predicts the permeability and average aperture of a fracture as a function of time under steady flow of water including the pressure solution at the asperity contact points. Several two-phase flow experiments in the presence of a fracture tip were performed in the past. At the

  7. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarad; H. Yasuhara; A. Alajmi

    2002-04-20

    The main objectives of this project are to quantify the changes in fracture porosity and multi-phase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (1) developing the direct experimental measurements of fracture aperture and topology using high-resolution x-ray micro-tomography, (2) modeling of fracture permeability in the presence of asperities and confining stress, and (3) simulation of two-phase fluid flow in a fracture and a layered matrix. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. The distribution of fracture aperture is a difficult issue that we are studying and developing methods of quantification. The difficulties are both numerical and conceptual. Numerically, the three-dimensional data sets include millions, and sometimes, billions of points, and pose a computational challenge. The conceptual difficulties derive from the rough nature of the fracture surfaces, and the heterogeneous nature of the rock matrix. However, the high-resolution obtained by the imaging system provides us a much needed measuring environment on rock samples that are subjected to simultaneous fluid flow and confining stress. The absolute permeability of a fracture depends on the behavior of the asperities that keep it open. A model is being developed that predicts the permeability and average aperture of a fracture as a function of time under steady flow of water including the pressure solution at the asperity contact points. Several two-phase flow experiments in the presence of a fracture tip were performed in the past. At the present time, we are developing an inverse process using a simulation model to understand the fluid flow patterns in

  8. Asymmetries of Knowledge and Epistemic Change in Social Gaming Interaction

    ERIC Educational Resources Information Center

    Piirainen-Marsh, Arja; Tainio, Liisa

    2014-01-01

    While a growing number of studies investigate the role of knowledge and interactional management of knowledge asymmetries in conversation analysis, the epistemic organization of multilingual and second language interactions is still largely unexplored. This article addresses this issue by investigating how knowledge asymmetries and changing…

  9. A UNIFYING CONCEPT FOR ASSESSING TOXICOLOGICAL INTERACTIONS: CHANGES IN SLOPE

    EPA Science Inventory

    Robust statistical methods are important to the evaluation of interactions among chemicals in a mixture. However, different concepts of interaction as applied to the statistical analysis of chemical mixture toxicology data or as used in environmental risk assessment often can ap...

  10. Change Trajectories for Parent-Child Interaction Sequences during Parent-Child Interaction Therapy for Child Physical Abuse

    ERIC Educational Resources Information Center

    Hakman, Melissa; Chaffin, Mark; Funderburk, Beverly; Silovsky, Jane F.

    2009-01-01

    Objective: Parent-child interaction therapy (PCIT) has been found to reduce future child abuse reports among physically abusive parents. Reductions in observed negative parenting behaviors mediated this benefit. The current study examined session-by-session interaction sequences in order to identify when during treatment these changes occur and…

  11. Social interaction is associated with changes in infants’ motor activity

    PubMed Central

    Scola, Céline; Bourjade, Marie; Jover, Marianne

    2015-01-01

    Background In developmental research, infants are commonly assumed to be early stakeholders in interactions with their caregivers. The tools that infants can use to interact with others vary from visual contact to smiling or vocalizing, and also include motor activity. However, surprisingly few studies have explored how the nature and context of social interactions affect infants’ engagement in motor activity. Methods We investigated the kinematic properties of foot and face movements produced by 11 infants aged between 5 and 9 months during six contrasting dyadic episodes (i.e. passive presence of a stranger or the infant's mother, weak or intense interaction with the stranger/mother as she sings a nursery play song). Results The infants’ face and foot motor activity was significantly reduced during the interactive episodes, compared with the episodes without any interaction, in both the mother and stranger conditions. Furthermore, the level of their motor activity was significantly lower in the stranger condition than in the mother one for some parameters. Conclusion These results are in line with those reported by previous studies and confirm the relevance of using motor activity to delineate the early forms of interactive episodes in infants. PMID:26546793

  12. Land Use and climate change interactions in tropical South America

    NASA Astrophysics Data System (ADS)

    Swann, A. L. S.; Longo, M.; Knox, R. G.; Lee, E.; Moorcroft, P. R.

    2015-12-01

    Ongoing agricultural expansion in Amazonia and the surrounding areas of Brazil is expected to continue over the next several decades as global food demand increases. The transition of natural forest and savannah ecosystems to pastureland and agricultural crops is predicted to create warmer and drier atmospheric conditions than the native vegetation. Compounding this effect, climate change is likely to lead to reduced transpiration fluxes as plants become more water efficient under higher atmospheric carbon dioxide (CO2) levels. Here we investigate the expected impacts of predicted future land use on the climate of South America as well as the potential impacts of increasing CO2. We find that the climate response to land use change generally consistent with expectations from previous global modeling simulations with drier conditions resulting from deforestation, however the direct changes in precipitation are relatively small (on order of a few percent). Local drying from land use change is driven primarily by decreases in evapo-transpiration associated with the loss of forest, and concomitant increases in runoff. Significant changes in convectively available potential energy and convective inhibition during the transition to the wet season indicate that the decrease in surface latent heat flux is indeed leading to a drier atmosphere, however these changes occur around a mean climatological state that is already very favorable for convection, and thus lead to relatively small changes in precipitation. The physiological effects of increasing CO2 alone also drive a reduction in precipitation, which is compounded by radiation-driven circulation changes. If these land use changes were to occur under a background state of drier conditions, such as those predicted for the future global climate model experiments, this additional atmospheric drying driven by land use change may be sufficient to decrease precipitation more substantially.

  13. The impact of orbital sampling, monthly averaging and vertical resolution on climate chemistry model evaluation with satellite observations

    NASA Astrophysics Data System (ADS)

    Aghedo, A. M.; Bowman, K. W.; Shindell, D. T.; Faluvegi, G.

    2011-03-01

    Ensemble climate model simulations used for the Intergovernmental Panel on Climate Change (IPCC) assessments have become important tools for exploring the response of the Earth System to changes in anthropogenic and natural forcings. The systematic evaluation of these models through global satellite observations is a critical step in assessing the uncertainty of climate change projections. This paper presents the technical steps required for using nadir sun-synchronous infrared satellite observations for multi-model evaluation and the uncertainties associated with each step. This is motivated by need to use satellite observations to evaluate climate models. We quantified the implications of the effect of satellite orbit and spatial coverage, the effect of variations in vertical sensitivity as quantified by the observation operator and the impact of averaging the operators for use with monthly-mean model output. We calculated these biases in ozone, carbon monoxide, atmospheric temperature and water vapour by using the output from two global chemistry climate models (ECHAM5-MOZ and GISS-PUCCINI) and the observations from the Tropospheric Emission Spectrometer (TES) satellite from January 2005 to December 2008. The results show that sampling and monthly averaging of the observation operators produce biases of less than ±3% for ozone and carbon monoxide throughout the entire troposphere in both models. Water vapour sampling biases were also within the insignificant range of ±3% (that is ±0.14 g kg-1) in both models. Sampling led to a temperature bias of ±0.3 K over the tropical and mid-latitudes in both models, and up to -1.4 K over the boundary layer in the higher latitudes. Using the monthly average of temperature and water vapour operators lead to large biases over the boundary layer in the southern-hemispheric higher latitudes and in the upper troposphere, respectively. Up to 8% bias was calculated in the upper troposphere water vapour due to monthly

  14. The impact of orbital sampling, monthly averaging and vertical resolution on climate chemistry model evaluation with satellite observations

    NASA Astrophysics Data System (ADS)

    Aghedo, A. M.; Bowman, K. W.; Shindell, D. T.; Faluvegi, G.

    2011-07-01

    Ensemble climate model simulations used for the Intergovernmental Panel on Climate Change (IPCC) assessments have become important tools for exploring the response of the Earth System to changes in anthropogenic and natural forcings. The systematic evaluation of these models through global satellite observations is a critical step in assessing the uncertainty of climate change projections. This paper presents the technical steps required for using nadir sun-synchronous infrared satellite observations for multi-model evaluation and the uncertainties associated with each step. This is motivated by need to use satellite observations to evaluate climate models. We quantified the implications of the effect of satellite orbit and spatial coverage, the effect of variations in vertical sensitivity as quantified by the observation operator and the impact of averaging the operators for use with monthly-mean model output. We calculated these biases in ozone, carbon monoxide, atmospheric temperature and water vapour by using the output from two global chemistry climate models (ECHAM5-MOZ and GISS-PUCCINI) and the observations from the Tropospheric Emission Spectrometer (TES) instrument on board the NASA-Aura satellite from January 2005 to December 2008. The results show that sampling and monthly averaging of the observation operators produce zonal-mean biases of less than ±3 % for ozone and carbon monoxide throughout the entire troposphere in both models. Water vapour sampling zonal-mean biases were also within the insignificant range of ±3 % (that is ±0.14 g kg-1) in both models. Sampling led to a temperature zonal-mean bias of ±0.3 K over the tropical and mid-latitudes in both models, and up to -1.4 K over the boundary layer in the higher latitudes. Using the monthly average of temperature and water vapour operators lead to large biases over the boundary layer in the southern-hemispheric higher latitudes and in the upper troposphere, respectively. Up to 8 % bias was

  15. Direct Radiative Forcing and Regional Climatic Effects of Anthropogenic Aerosols Over East Asia: A Regional Coupled Climate-Chemistry/Aerosol Model Study

    SciTech Connect

    Giorgi, Filippo; Bi, Xunqiang; Qian, Yun )

    2002-09-01

    We present a series of regional climate model simulations aimed at assessing the radiative forcing and surface climatic effects of anthropogenic sulfate and fossil fuel soot over east Asia. The simulations are carried out with a coupled regional climate-chemistry/aerosol model for the 5-year period of 1993-1997 using published estimates of sulfur emissions for the period. Anthropogenic sulfate induces a negative radiative forcing spatially varying from -1 to -8 W/m2 in the winter to -1 to -15 W/m2 in the summer, with maxima over the Sichan Basin of southwest China and over some areas of east and northeast China. This forcing induces a surface cooling in the range of -0.1 to -0.7 K. Fossil fuel soot exerts a positive atmospheric radiative forcing of 0.5 to 2 W/m2 and enhances the surface cooling by a few tenths of K due to increased surface shielding from solar radiation. Doubling of sulfur emissions induces a substantial increase in radiative forcing (up to -7 to -8 W/m2) and associated surface cooling. With doubled sulfur emissions, the surface cooling exceeds -1 K and is statistically significant at the 90% confidence level over various areas of China. The aerosol forcing and surface cooling tend to inhibit precipitation over the region, although this effect is relatively small in the simulations. Some features of the simulated aerosol-induced cooling are consistent with temperature trends observed in recent decades over different regions of China.

  16. Implications of Glacier Volume Change for Ice-Ocean Interactions

    NASA Astrophysics Data System (ADS)

    Hood, E. W.; O'Neel, S.; Fellman, J.; Bidlack, A.; Arendt, A. A.; Arimitsu, M.; Spencer, R. G.

    2015-12-01

    Changes in climate are forcing complex glaciological responses that can be transmitted to downstream ecosystems via glacier runoff. Along the Gulf of Alaska, rates of glacier mass loss are among the highest measured on Earth. Changes in glacier volume in this region are altering the amount of glacier runoff delivered to the coastal ocean. Moreover, shifts in glacier extent are changing the location of the ice-ocean interface and, in cases where tidewater glaciers become grounded, fundamentally altering circulation in glacierized fjords. The runoff from glacier ecosystems is unique in terms of its physical and chemical properties when compared to runoff from non-glacial ecosystems. For example, the silt and chemical constituents in glacier discharge alter light penetration and the nutrient regime in near-shore marine ecosystems, which, in turn, influence levels of marine primary productivity. Future changes in the magnitude, timing, and location of glacier runoff have important implications for biogeochemical and ecological processes in glacially-dominated fjords and estuaries. This talk will highlight research from glacierized watersheds and fjords to synthesize what is known about the physical, chemical, and biological linkages that characterize icefield-ocean ecosystems along the Gulf of Alaska.

  17. An Interactional Model for Resistance to Change in Educational Institutions.

    ERIC Educational Resources Information Center

    Gjerde, Per F.

    Although schools have served as a major target of both educational and mental-health oriented interventions, they have shown a marked tendency to assimilate innovative programs into existing patterns. This paper analyzes the sources and manifestations of resistance to change in schools and discusses the implications of such resistance for the…

  18. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change.

    PubMed

    McCluney, Kevin E; Belnap, Jayne; Collins, Scott L; González, Angélica L; Hagen, Elizabeth M; Nathaniel Holland, J; Kotler, Burt P; Maestre, Fernando T; Smith, Stanley D; Wolf, Blair O

    2012-08-01

    Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts

  19. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change

    USGS Publications Warehouse

    McCluney, Kevin E.; Belnap, Jayne; Collins, Scott L.; González, Angélica L.; Hagen, Elizabeth M.; Holland, J. Nathaniel; Kotler, Burt P.; Maestre, Fernando T.; Smith, Stanley D.; Wolf, Blair O.

    2012-01-01

    Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts

  20. Effects of Solar UV Radiation and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    EPA Science Inventory

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions...

  1. Common Processes of Change in Psychotherapy and Seven Other Social Interactions.

    ERIC Educational Resources Information Center

    Lampropoulos, Georgios K.

    2001-01-01

    Argues that change processes in psychotherapy can be understood more clearly by comparing them with other change-inducing social relationships. In showing how this may be done, describes different social interactions and discusses them in terms of a parsimonious set of common factors in change. Stresses the importance of the cross-fertilization of…

  2. Interactions between environmental changes and brain plasticity in birds.

    PubMed

    Barnea, Anat

    2009-09-01

    Neurogenesis and neuronal recruitment occur in many vertebrates, including humans. Most of the new neurons die before reaching their destination. Those which survive migrate to various brain regions, replace older ones and connect to existing circuits. Evidence suggests that this replacement is related to acquisition of new information. Therefore, neuronal replacement can be seen as a form of brain plasticity that enables organisms to adjust to environmental changes. However, direct evidence of a causal link between replacement and learning remains elusive. Our hypothesis is that increased neuronal recruitment is associated with increase in memory load. Moreover, since neuronal recruitment is part of a turnover process, we assume that the same conditions that favor survival of some neurons induce the death of others. I present studies that investigated the effect of various behaviors and environmental conditions (food-hoarding, social change, reproductive cycle) on neuronal recruitment and survival in adult avian brains, and discuss how these phenomena relate to the life of animals. I offer a frame and rationale for comparing neuronal replacement in the adult brain, in order to uncover the pressures, rules, and mechanisms that govern its constant rejuvenation. The review emphasizes the importance of using various approaches (behavioral, anatomical, cellular and hormonal) in neuroethological research, and the need to study natural populations, in order to fully understand how neurogenesis and neuronal replacement contribute to life of animals. Finally, the review indicates to future directions and ends with the hope that a better understanding of adult neuronal replacement will lead to medical applications. PMID:19361509

  3. Complex interactions in Lake Michigan’s rapidly changing ecosystem

    USGS Publications Warehouse

    Vanderploeg, Henry A.; Bunnell, David B.; Carrick, Hunter J.; Hook, Tomas O.

    2015-01-01

    For over 30 years, Lake Michigan’s food web has been in a constant state of transition from reductions in nutrient loading and proliferation of invasive species at multiple trophic levels. In particular, there has been concern about impacts from the invasive predatory cercopagids (Bythotrephes longimanus and Cercopagis pengoi) and expanding dreissenid mussel and round goby populations. This special issue brings together papers that explore the status of the Lake Michigan food web and the factors responsible for these changes, and suggests research paths that must be taken for understanding and predicting system behavior. This introductory paper describes the special issue origin, presents an overview of the papers, and draws overarching conclusions from the papers.

  4. An Interactive Multi-Model for Consensus on Climate Change

    SciTech Connect

    Kocarev, Ljupco

    2014-07-02

    This project purports to develop a new scheme for forming consensus among alternative climate models, that give widely divergent projections as to the details of climate change, that is more intelligent than simply averaging the model outputs, or averaging with ex post facto weighting factors. The method under development effectively allows models to assimilate data from one another in run time with weights that are chosen in an adaptive training phase using 20th century data, so that the models synchronize with one another as well as with reality. An alternate approach that is being explored in parallel is the automated combination of equations from different models in an expert-system-like framework.

  5. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarado; A. Alajmi; Z. Karpyn; N. Mohammed; S. Al-Enezi

    2005-06-15

    The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) quantifying the effect of confining stress on the distribution of fracture aperture, and (c) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress on the nature of the rock and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual descriptions of the process are shown in the report while detailed analysis of the behavior of the distribution of fracture aperture is in progress. Both extensional and shear fractures are being considered. The initial multi-phase flow tests were done in extensional fractures. Several rock samples with induced shear fracture are being studies, and some of the new results are presented in this report. These samples are being scanned in order to

  6. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarado; A. Alajmi; Z. Karpyn; N. Mohammed; S. Al-Enezi

    2005-06-15

    The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) quantifying the effect of confining stress on the distribution of fracture aperture, and (c) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress on the nature of the rock and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual descriptions of the process are shown in the report while detailed analysis of the behavior of the distribution of fracture aperture is in progress. Both extensional and shear fractures are being considered. The initial multi-phase flow tests were done in extensional fractures. Several rock samples with induced shear fracture are being studied, and some of the new results are presented in this report. These samples are being scanned in order to

  7. Irukandji jellyfish polyps exhibit tolerance to interacting climate change stressors.

    PubMed

    Klein, Shannon G; Pitt, Kylie A; Rathjen, Kristen A; Seymour, Jamie E

    2014-01-01

    Increasing ocean temperatures and strengthening boundary currents have caused the poleward migration of many marine species. Cubozoan jellyfish known to cause Irukandji syndrome have historically been confined to tropical waters but may be expanding into subtropical regions. Here, we examine the interactive effects of warming and acidification on the population dynamics of polyps of an Irukandji jellyfish, Alatina nr mordens, and the formation of statoliths in newly metamorphosed medusae, to determine if this jellyfish could tolerate future conditions predicted for southeast Queensland (SEQ), Australia. Two experiments, examining the orthogonal factors of temperature and pH, were undertaken. Experiment 1 mimicked the current, ca. 2050 and ca. 2100 summer temperature and pH conditions predicted for SEQ using A1F1 scenarios (temperature: 25, 27, 29 °C; pH: 7.9, 7.8, 7.6) and Experiment 2 mimicked current and future winter conditions (18 and 22 °C, pH 7.9, 7.8, 7.6). All polyps in Experiment 1 survived and budded. Fewer polyps budded in the lower pH treatments; however, patterns varied slightly among temperature treatments. Statoliths at pH 7.6 were 24% narrower than those at pH 7.8 and 7.9. Most polyps survived the winter conditions mimicked by Experiment 2 but only polyps in the 22 °C, pH 7.9 treatment increased significantly. The current absence of A. nr mordens medusae in SEQ, despite the polyps' ability to tolerate the current temperature and pH conditions, suggests that ecological, rather than abiotic factors currently limit their distribution. Observations that budding was lower under low pH treatments suggest that rates of asexual reproduction will likely be much slower in the future. We consider that A. nr mordens polyps are likely to tolerate future conditions but are unlikely to thrive in the long term. However, if polyps can overcome potential ecological boundaries and acidification proceeds slowly A. nr mordens could expand polewards in the short

  8. Flavor changing heavy Higgs interactions at the LHC

    NASA Astrophysics Data System (ADS)

    Altunkaynak, Baris; Hou, Wei-Shu; Kao, Chung; Kohda, Masaya; McCoy, Brent

    2015-12-01

    A general two Higgs doublet model (2HDM) is adopted to study the signature of flavor changing neutral Higgs (FCNH) decay ϕ0 → t c bar + t bar c, where ϕ0 could be a CP-even scalar (H0) or a CP-odd pseudoscalar (A0). Measurement of the light 125 GeV neutral Higgs boson (h0) couplings at the Large Hadron Collider (LHC) favor the decoupling limit or the alignment limit of a 2HDM, in which gauge boson and diagonal fermion couplings of h0 approach Standard Model values. In such limit, FCNH couplings of h0 are naturally suppressed by a small mixing parameter cos ⁡ (β - α), while the off-diagonal couplings of heavier neutral scalars ϕ0 are sustained by sin ⁡ (β - α) ∼ 1. We study physics background from dominant processes with realistic acceptance cuts and tagging efficiencies. Promising results are found for the LHC running at 13 or 14 TeV collision energies.

  9. Flavor changing heavy Higgs interactions at the LHC

    NASA Astrophysics Data System (ADS)

    McCoy, Brent; Altunkaynak, Baris; Kao, Chung; Hou, Wei-Shou; Kohda, Masaya

    2016-03-01

    A general two Higgs doublet model (2HDM) is adopted to study the signature of flavor changing neutral Higgs (FCNH) decay ϕ0 --> t c + t c , where ϕ0 could be a CP-even scalar (H0) or a CP-odd pseudoscalar (A0). Measurement of the light 126 GeV neutral Higgs boson (h0) couplings at the Large Hadron Collider (LHC) favor the decoupling limit or the alignment limit of a 2HDM, in which gauge boson and diagonal fermion couplings of h0 approach Standard Model values. In such a limit, FCNH couplings of h0 are naturally suppressed by a small mixing parameter cos (β - α) , while the off-diagonal couplings of heavier neutral scalars ϕ0 are sustained by sin (β - α) ~ 1 . We study physics background from dominant processes with realistic acceptance cuts and tagging efficiencies. Promising results are found for the LHC running at 13 or 14 TeV collision energies. Academia Sinica, National Taiwan University; OU Supercomputing Center for Education & Research; U.S. Department of Energy, Grant No. DEFG01-13ER41979; Academic Summit Grants: MOST 103-2745-M-002-001-ASP, NTU-EPR-103R8915, and NSC 102-2112-M-033-007-MY3.

  10. The Interactive Relationship of Dogmatism and Attitude Discrepancy-Congruency to Attitude Change.

    ERIC Educational Resources Information Center

    McCann, Stewart J. H.; Hamilton, Marshall L.

    1978-01-01

    Hypothesized that dogmatism and attitude discrepancy-congruency would be interactively related to attitude change. Results suggest that supportive information may be more effective in polarizing opinions or attitudes of nondogmatic persons than dogmatic persons. (Author)

  11. UNEP REPORT, "ENVIRONMENTAL EFFECTS OF OZONE DEPLETION AND ITS INTERACTIONS WITH CLIMATE CHANGE: 2002 ASSESSMENT."

    EPA Science Inventory

    United Nations Environment Programme (UNEP) Report on "Environmental effects of ozone depletion and its interactions with climate change: 2002 assessment." The chapters were published in the first issue (No. 1) of the 2003 volume of journal "Photochemical & Photobiological Scien...

  12. The Administrative Internship and Role Change: A Study of the Relationship Between Interaction and Attitudes

    ERIC Educational Resources Information Center

    Ferreira, Joseph L.

    1970-01-01

    In interpreting data gathered in an administrative internship program, the author suggests that certain attitude changes, taken as an index of role shift, are associated with interaction patterns with significant others. (Author/MF)

  13. Multi-Phase Fracture-Matrix Interactions Under Stress Changes

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarao; A. Alajmi; Z. Karpyn; N. Mohammed; S. Al-Enezi

    2005-12-07

    The main objectives of this project are to quantify the changes in fracture porosity and multi-phase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) counter-current fluid transport between the matrix and the fracture, (c) studying the effect of confining stress on the distribution of fracture aperture and two-phase flow, and (d) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress, on the nature of the rock, and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual and detailed descriptions of the process are shown in the report. Both extensional and shear fractures have been considered. A series of water imbibition tests were conducted in which water was injected into a fracture and its migration into the matrix was monitored with CT and DR x-ray techniques. The objective was to understand the impact of the

  14. Efficient fold-change detection based on protein-protein interactions.

    PubMed

    Buijsman, W; Sheinman, M

    2014-02-01

    Various biological sensory systems exhibit a response to a relative change of the stimulus, often referred to as fold-change detection. In the past few years, fold-change detecting mechanisms, based on transcriptional networks, have been proposed. Here we present a fold-change detecting mechanism, based on protein-protein interactions, consisting of two interacting proteins. This mechanism does not consume chemical energy and is not subject to transcriptional and translational noise, in contrast to previously proposed mechanisms. We show by analytical and numerical calculations that the mechanism is robust and can have a fast, precise, and efficient response for parameters that are relevant to eukaryotic cells. PMID:25353514

  15. After Early Autism Diagnosis: Changes in Intervention and Parent-Child Interaction

    ERIC Educational Resources Information Center

    Suma, Katharine; Adamson, Lauren B.; Bakeman, Roger; Robins, Diana L.; Abrams, Danielle N.

    2016-01-01

    This study documents the relation between an autism spectrum disorder (ASD) diagnosis, increases in intervention, and changes in parent-child interaction quality. Information about intervention and observations of interaction were collected before diagnosis and a half year after diagnosis for 79 low-risk toddlers who had screened positive for ASD…

  16. Studying Learning Processes of Student Teachers with Stimulated Recall Interviews through Changes in Interactive Cognitions

    ERIC Educational Resources Information Center

    Schepens, Annemie; Aelterman, Antonia; Van Keer, Hilde

    2007-01-01

    This article describes a qualitative study into student teachers' learning processes through changes in their interactive cognitions. First, theoretical propositions about the relation between learning to teach, professional development, and practical knowledge are defined. Next, the procedure to grasp interactive cognitions as part of practical…

  17. Agonistic interactions elicit rapid changes in brain nonapeptide levels in zebrafish.

    PubMed

    Teles, Magda C; Gozdowska, Magdalena; Kalamarz-Kubiak, Hanna; Kulczykowska, Ewa; Oliveira, Rui F

    2016-08-01

    The teleost fish nonapeptides, arginine vasotocin (AVT) and isotocin (IT), have been implicated in the regulation of social behavior. These peptides are expected to be involved in acute and transient changes in social context, in order to be efficient in modulating the expression of social behavior according to changes in the social environment. Here we tested the hypothesis that short-term social interactions are related to changes in the level of both nonapeptides across different brain regions. For this purpose we exposed male zebrafish to two types of social interactions: (1) real opponent interactions, from which a Winner and a Loser emerged; and (2) mirror-elicited interactions, that produced individuals that did not experience a change in social status despite expressing similar levels of aggressive behavior to those of participants in real-opponent fights. Non-interacting individuals were used as a reference group. Each social phenotype (i.e. Winners, Losers, Mirror-fighters) presented a specific brain profile of nonapeptides when compared to the reference group. Moreover, the comparison between the different social phenotypes allowed to address the specific aspects of the interaction (e.g. assessment of opponent aggressive behavior vs. self-assessment of expressed aggressive behavior) that are linked with neuropeptide responses. Overall, agonistic interactions seem to be more associated with the changes in brain AVT than IT, which highlights the preferential role of AVT in the regulation of aggressive behavior already described for other species. PMID:27235811

  18. How will biotic interactions influence climate change-induced range shifts?

    PubMed

    HilleRisLambers, Janneke; Harsch, Melanie A; Ettinger, Ailene K; Ford, Kevin R; Theobald, Elinore J

    2013-09-01

    Biotic interactions present a challenge in determining whether species distributions will track climate change. Interactions with competitors, consumers, mutualists, and facilitators can strongly influence local species distributions, but few studies assess how and whether these interactions will impede or accelerate climate change-induced range shifts. In this paper, we explore how ecologists might move forward on this question. We first outline the conditions under which biotic interactions can result in range shifts that proceed faster or slower than climate velocity and result in ecological surprises. Next, we use our own work to demonstrate that experimental studies documenting the strength of biotic interactions across large environmental gradients are a critical first step for understanding whether they will influence climate change-induced range shifts. Further progress could be made by integrating results from these studies into modeling frameworks to predict how or generalize when biotic interactions mediate how changing climates influence range shifts. Finally, we argue that many more case studies like those described here are needed to explore the importance of biotic interactions during climate change-induced range shifts. PMID:23876073

  19. Examining the interaction between land use change, temperature extremes and land-atmosphere interactions

    NASA Astrophysics Data System (ADS)

    Hirsch, Annette L.; Pitman, Andy J.; Kala, Jatin; Lorenz, Ruth; Donat, Markus G.

    2016-04-01

    Using the Weather and Research Forecasting Model, we examine the combined impact of land-atmosphere coupling and land use change (LUC) on simulated temperature extremes. The sensitivity of the impact of LUC on temperature extremes to the choice of planetary boundary layer (PBL) and cumulus parameterization schemes are also evaluated to examine whether the impact of LUC on temperature extremes is dependent on the atmospheric model physics and if this impact is modulated by changes in land-atmosphere coupling. A decomposition of the surface energy balance is used to examine the different responses to LUC. Results show a consistent weakening in the soil moisture-temperature coupling strength with LUC irrespective of the atmospheric model physics tested here. In contrast, temperature extremes show an asymmetric response to LUC dependent on the choice of PBL scheme, which is linked to differences in the parameterization of vertical transport. This influences convective precipitation, contributing a positive feedback on soil moisture and consequently on the partitioning of the surface turbulent fluxes. The results suggest that the impact of LUC on temperature extremes depends on the land-atmosphere coupling that in turn depends on the choice of PBL. Indeed, the sign of the change in temperature extremes due to LUC can be changed simply by altering the choice of PBL schemes examined here.

  20. Changes in Children's Peer Interactions Following a Natural Disaster: How Predisaster Bullying and Victimization Rates Changed Following Hurricane Katrina

    ERIC Educational Resources Information Center

    Terranova, Andrew M.; Boxer, Paul; Morris, Amanda Sheffield

    2009-01-01

    Youth exposed to disasters experience stress and adjustment difficulties, which likely influence their interactions with peers. In this study, we examined changes in bullying and peer victimization in two cohorts of children. Youth from an area affected by Hurricane Katrina were assessed pre- and postdisaster (n = 96, mean [M] = 10.9 years old,…

  1. Phenological overlap of interacting species in a changing climate: an assessment of available approaches.

    PubMed

    Rafferty, Nicole E; Caradonna, Paul J; Burkle, Laura A; Iler, Amy M; Bronstein, Judith L

    2013-09-01

    Concern regarding the biological effects of climate change has led to a recent surge in research to understand the consequences of phenological change for species interactions. This rapidly expanding research program is centered on three lines of inquiry: (1) how the phenological overlap of interacting species is changing, (2) why the phenological overlap of interacting species is changing, and (3) how the phenological overlap of interacting species will change under future climate scenarios. We synthesize the widely disparate approaches currently being used to investigate these questions: (1) interpretation of long-term phenological data, (2) field observations, (3) experimental manipulations, (4) simulations and nonmechanistic models, and (5) mechanistic models. We present a conceptual framework for selecting approaches that are best matched to the question of interest. We weigh the merits and limitations of each approach, survey the recent literature from diverse systems to quantify their use, and characterize the types of interactions being studied by each of them. We highlight the value of combining approaches and the importance of long-term data for establishing a baseline of phenological synchrony. Future work that scales up from pairwise species interactions to communities and ecosystems, emphasizing the use of predictive approaches, will be particularly valuable for reaching a broader understanding of the complex effects of climate change on the phenological overlap of interacting species. It will also be important to study a broader range of interactions: to date, most of the research on climate-induced phenological shifts has focused on terrestrial pairwise resource-consumer interactions, especially those between plants and insects. PMID:24102003

  2. Phenological overlap of interacting species in a changing climate: an assessment of available approaches

    PubMed Central

    Rafferty, Nicole E; CaraDonna, Paul J; Burkle, Laura A; Iler, Amy M; Bronstein, Judith L

    2013-01-01

    Concern regarding the biological effects of climate change has led to a recent surge in research to understand the consequences of phenological change for species interactions. This rapidly expanding research program is centered on three lines of inquiry: (1) how the phenological overlap of interacting species is changing, (2) why the phenological overlap of interacting species is changing, and (3) how the phenological overlap of interacting species will change under future climate scenarios. We synthesize the widely disparate approaches currently being used to investigate these questions: (1) interpretation of long-term phenological data, (2) field observations, (3) experimental manipulations, (4) simulations and nonmechanistic models, and (5) mechanistic models. We present a conceptual framework for selecting approaches that are best matched to the question of interest. We weigh the merits and limitations of each approach, survey the recent literature from diverse systems to quantify their use, and characterize the types of interactions being studied by each of them. We highlight the value of combining approaches and the importance of long-term data for establishing a baseline of phenological synchrony. Future work that scales up from pairwise species interactions to communities and ecosystems, emphasizing the use of predictive approaches, will be particularly valuable for reaching a broader understanding of the complex effects of climate change on the phenological overlap of interacting species. It will also be important to study a broader range of interactions: to date, most of the research on climate-induced phenological shifts has focused on terrestrial pairwise resource–consumer interactions, especially those between plants and insects. PMID:24102003

  3. Land-Atmosphere Interactions in Cold Environments (LATICE): The role of Atmosphere - Biosphere - Cryosphere - Hydrosphere interactions in a changing climate

    NASA Astrophysics Data System (ADS)

    Tallaksen, Lena M.; Burkhart, John F.; Stordal, Frode

    2015-04-01

    Climate change is impacting the high latitudes more rapidly and significantly than any other region of the Earth because of feedback processes between the atmosphere and the underlying surface. A warmer climate has already led to thawing of permafrost, reduced snow cover and a longer growing season; changes, which in turn influence the atmospheric circulation and the hydrological cycle. Still, many studies rely on one-way coupling between the atmosphere and the land surface, thereby neglecting important interactions and feedbacks. The observation, understanding and prediction of such processes from local to regional and global scales, represent a major scientific challenge that requires multidisciplinary scientific effort. The successful integration of earth observations (remote and in-situ data) and model development requires a harmonized research effort between earth system scientists, modelers and the developers of technologies and sensors. LATICE, which is recognized as a priority research area by the Faculty of Mathematics and Natural Sciences at the University of Oslo, aims to advance the knowledge base concerning land atmosphere interactions and their role in controlling climate variability and climate change at high northern latitudes. The consortium consists of an interdisciplinary team of experts from the atmospheric and terrestrial (hydrosphere, cryosphere and biosphere) research groups, together with key expertise on earth observations and novel sensor technologies. LATICE addresses critical knowledge gaps in the current climate assessment capacity through: i) Improving parameterizations of processes in earth system models controlling the interactions and feedbacks between the land (snow, ice, permafrost, soil and vegetation) and the atmosphere at high latitudes, including the boreal, alpine and artic zone. ii) Assessing the influence of climate and land cover changes on water and energy fluxes. iii) Integrating remote earth observations with in

  4. Land-Atmosphere Interactions in Cold Environments (LATICE): The role of Atmosphere - Biosphere - Cryosphere - Hydrosphere interactions in a changing climate

    NASA Astrophysics Data System (ADS)

    Burkhart, J. F.; Tallaksen, L. M.; Stordal, F.; Berntsen, T.; Westermann, S.; Kristjansson, J. E.; Etzelmuller, B.; Hagen, J. O.; Schuler, T.; Hamran, S. E.; Lande, T. S.; Bryn, A.

    2015-12-01

    Climate change is impacting the high latitudes more rapidly and significantly than any other region of the Earth because of feedback processes between the atmosphere and the underlying surface. A warmer climate has already led to thawing of permafrost, reducing snow cover and a longer growing season; changes, which in turn influence the atmospheric circulation and the hydrological cycle. Still, many studies rely on one-way coupling between the atmosphere and the land surface, thereby neglecting important interactions and feedbacks. The observation, understanding and prediction of such processes from local to regional and global scales, represent a major scientific challenge that requires multidisciplinary scientific effort. The successful integration of earth observations (remote and in-situ data) and model development requires a harmonized research effort between earth system scientists, modelers and the developers of technologies and sensors. LATICE, which is recognized as a priority research area by the Faculty of Mathematics and Natural Sciences at the University of Oslo, aims to advance the knowledge base concerning land atmosphere interactions and their role in controlling climate variability and climate change at high northern latitudes. The consortium consists of an interdisciplinary team of experts from the atmospheric and terrestrial (hydrosphere, cryosphere and biosphere) research groups, together with key expertise on earth observations and novel sensor technologies. LATICE addresses critical knowledge gaps in the current climate assessment capacity through: Improving parameterizations of processes in earth system models controlling the interactions and feedbacks between the land (snow, ice, permafrost, soil and vegetation) and the atmosphere at high latitudes, including the boreal, alpine and artic zone. Assessing the influence of climate and land cover changes on water and energy fluxes. Integrating remote earth observations with in-situ data and

  5. Transient simulations of historical climate change including interactive carbon emissions from land-use change.

    NASA Astrophysics Data System (ADS)

    Matveev, A.; Matthews, H. D.

    2009-04-01

    Carbon fluxes from land conversion are among the most uncertain variables in our understanding of the contemporary carbon cycle, which limits our ability to estimate both the total human contribution to current climate forcing and the net effect of terrestrial biosphere changes on atmospheric CO2 increases. The current generation of coupled climate-carbon models have made significant progress in simulating the coupled climate and carbon cycle response to anthropogenic CO2 emissions, but do not typically include land-use change as a dynamic component of the simulation. In this work we have incorporated a book-keeping land-use carbon accounting model into the University of Victoria Earth System Climate Model (UVic ESCM), and intermediate-complexity coupled climate-carbon model. The terrestrial component of the UVic ESCM allows an aerial competition of five plant functional types (PFTs) in response to climatic conditions and area availability, and tracks the associated changes in affected carbon pools. In order to model CO2 emissions from land conversion in the terrestrial component of the model, we calculate the allocation of carbon to short and long-lived wood products following specified land-cover change, and use varying decay timescales to estimate CO2 emissions. We use recently available spatial datasets of both crop and pasture distributions to drive a series of transient simulations and estimate the net contribution of human land-use change to historical carbon emissions and climate change.

  6. A three-way perspective of stoichiometric changes on host-parasite interactions.

    PubMed

    Aalto, Sanni L; Decaestecker, Ellen; Pulkkinen, Katja

    2015-07-01

    Changes in environmental nutrients play a crucial role in driving disease dynamics, but global patterns in nutrient-driven changes in disease are difficult to predict. In this paper we use ecological stoichiometry as a framework to review host-parasite interactions under changing nutrient ratios, focusing on three pathways: (i) altered host resistance and parasite virulence through host stoichiometry (ii) changed encounter or contact rates at population level, and (iii) changed host community structure. We predict that the outcome of nutrient changes on host-parasite interactions depends on which pathways are modified, and suggest that the outcome of infection could depend on the overlap in stoichiometric requirements of the host and the parasite. We hypothesize that environmental nutrient enrichment alters infectivity dynamics leading to fluctuating selection dynamics in host-parasite coevolution. PMID:25978937

  7. Interactions Between Climate Change, Fire and Invasive Plants in California Ecosystems

    NASA Astrophysics Data System (ADS)

    Keeley, J. E.

    2007-12-01

    Changes in fire regimes are predicted in many climate change scenarios. The types of changes are greatly affected by the fuel structure of the ecosystem and different trajectories of change are expected in surface fire regimes than in crown fire regimes. However, in the multi-factorial world of natural ecosystems, climate is only one of the drivers of future change and some of the known threats to ecosystem stability are expected to push the system over particular thresholds of tolerance very rapidly. Invasive species have been widely recognized as drivers of ecosystem change, often generating feedback effects that alter fuel structure and future fire behavior. Human demographic changes, and the concomitant changes in anthropogenic fire ignitions are an additional threat to future ecosystem stability. I will address how these factors might interact with climate change in ecosystems of very different fuel structure, including surface fire ponderosa pine forests and crown fire chaparral shrublands in California.

  8. After Early Autism Diagnosis: Changes in Intervention and Parent-Child Interaction.

    PubMed

    Suma, Katharine; Adamson, Lauren B; Bakeman, Roger; Robins, Diana L; Abrams, Danielle N

    2016-08-01

    This study documents the relation between an autism spectrum disorder (ASD) diagnosis, increases in intervention, and changes in parent-child interaction quality. Information about intervention and observations of interaction were collected before diagnosis and a half year after diagnosis for 79 low-risk toddlers who had screened positive for ASD risk during a well-baby checkup. Children diagnosed with ASD (n = 44) were 2.69 times more likely to increase intervention hours. After ASD diagnosis, the relation between intervention and interaction quality was complex: although increases in intervention and interaction quality were only modestly related, the overall amount of intervention after diagnosis was associated with higher quality interactions. Moreover, lower quality interactions before diagnosis significantly increased the likelihood that intervention would increase post-diagnosis. PMID:27193183

  9. Environmental Enrichments for a Group of Captive Macaws: Low Interaction Does Not Mean Low Behavioral Changes.

    PubMed

    Reimer, Jéssica; Maia, Caroline Marques; Santos, Eliana Ferraz

    2016-01-01

    Environmental enrichment has been widely used to improve conditions for nonhuman animals in captivity. However, there is no consensus about the best way to evaluate the success of enrichments. This study evaluated whether the proportion of time spent interacting with enrichments indicated the proportion of overall behavioral changes. Six environmental enrichments were introduced in succession to 16 captive macaws, and interaction of the animals with them as well as the behaviors of the group were recorded before and during the enrichments. All of the enrichments affected the proportions of time spent in different behaviors. Macaws interacted more with certain items (hibiscus and food tree) than with others (a toy or swings and stairs), but introduction of the enrichments that invoked the least interaction caused as many behavioral changes as those that invoked the most. Moreover, feeding behavior was only affected by the enrichment that invoked the least interaction, a change not detected by a general analysis of enrichment effects. In conclusion, little interaction with enrichment does not mean little change in behavior, and the effects of enrichments are more complex than previously considered. PMID:27135378

  10. The Effects of Interactive Stratospheric Chemistry on Antarctic and Southern Ocean Climate Change in an AOGCM

    NASA Technical Reports Server (NTRS)

    Li, Feng; Newman, Paul; Pawson, Steven; Waugh, Darryn

    2014-01-01

    Stratospheric ozone depletion has played a dominant role in driving Antarctic climate change in the last decades. In order to capture the stratospheric ozone forcing, many coupled atmosphere-ocean general circulation models (AOGCMs) prescribe the Antarctic ozone hole using monthly and zonally averaged ozone field. However, the prescribed ozone hole has a high ozone bias and lacks zonal asymmetry. The impacts of these biases on model simulations, particularly on Southern Ocean and the Antarctic sea ice, are not well understood. The purpose of this study is to determine the effects of using interactive stratospheric chemistry instead of prescribed ozone on Antarctic and Southern Ocean climate change in an AOGCM. We compare two sets of ensemble simulations for the 1960-2010 period using different versions of the Goddard Earth Observing System 5 - AOGCM: one with interactive stratospheric chemistry, and the other with prescribed monthly and zonally averaged ozone and 6 other stratospheric radiative species calculated from the interactive chemistry simulations. Consistent with previous studies using prescribed sea surface temperatures and sea ice concentrations, the interactive chemistry runs simulate a deeper Antarctic ozone hole and consistently larger changes in surface pressure and winds than the prescribed ozone runs. The use of a coupled atmosphere-ocean model in this study enables us to determine the impact of these surface changes on Southern Ocean circulation and Antarctic sea ice. The larger surface wind trends in the interactive chemistry case lead to larger Southern Ocean circulation trends with stronger changes in northerly and westerly surface flow near the Antarctica continent and stronger upwelling near 60S. Using interactive chemistry also simulates a larger decrease of sea ice concentrations. Our results highlight the importance of using interactive chemistry in order to correctly capture the influences of stratospheric ozone depletion on climate

  11. Effects of solar UV radiation and climate change on biogeochemical cycling: Interactions and feedbacks

    SciTech Connect

    Erickson III, David J

    2011-01-01

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions of these effects with climate change, including feedbacks on climate. Such interactions occur in both terrestrial and aquatic ecosystems. While there is significant uncertainty in the quantification of these effects, they could accelerate the rate of atmospheric CO{sub 2} increase and subsequent climate change beyond current predictions. The effects of predicted changes in climate and solar UV radiation on carbon cycling in terrestrial and aquatic ecosystems are expected to vary significantly between regions. The balance of positive and negative effects on terrestrial carbon cycling remains uncertain, but the interactions between UV radiation and climate change are likely to contribute to decreasing sink strength in many oceanic regions. Interactions between climate and solar UV radiation will affect cycling of elements other than carbon, and so will influence the concentration of greenhouse and ozone-depleting gases. For example, increases in oxygen-deficient regions of the ocean caused by climate change are projected to enhance the emissions of nitrous oxide, an important greenhouse and ozone-depleting gas. Future changes in UV-induced transformations of aquatic and terrestrial contaminants could have both beneficial and adverse effects. Taken in total, it is clear that the future changes in UV radiation coupled with human-caused global change will have large impacts on biogeochemical cycles at local, regional and global scales.

  12. Effects of solar UV radiation and climate change on biogeochemical cycling: interactions and feedbacks.

    PubMed

    Zepp, R G; Erickson, D J; Paul, N D; Sulzberger, B

    2011-02-01

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions of these effects with climate change, including feedbacks on climate. Such interactions occur in both terrestrial and aquatic ecosystems. While there is significant uncertainty in the quantification of these effects, they could accelerate the rate of atmospheric CO(2) increase and subsequent climate change beyond current predictions. The effects of predicted changes in climate and solar UV radiation on carbon cycling in terrestrial and aquatic ecosystems are expected to vary significantly between regions. The balance of positive and negative effects on terrestrial carbon cycling remains uncertain, but the interactions between UV radiation and climate change are likely to contribute to decreasing sink strength in many oceanic regions. Interactions between climate and solar UV radiation will affect cycling of elements other than carbon, and so will influence the concentration of greenhouse and ozone-depleting gases. For example, increases in oxygen-deficient regions of the ocean caused by climate change are projected to enhance the emissions of nitrous oxide, an important greenhouse and ozone-depleting gas. Future changes in UV-induced transformations of aquatic and terrestrial contaminants could have both beneficial and adverse effects. Taken in total, it is clear that the future changes in UV radiation coupled with human-caused global change will have large impacts on biogeochemical cycles at local, regional and global scales. PMID:21253663

  13. Functional Ecological Gene Networks to Reveal the Changes Among Microbial Interactions Under Elevated Carbon Dioxide Conditions

    SciTech Connect

    Deng, Ye; Zhou, Jizhong; Luo, Feng; He, Zhili; Tu, Qichao; Zhi, Xiaoyang

    2010-05-17

    Biodiversity and its responses to environmental changes is a central issue in ecology, and for society. Almost all microbial biodiversity researches focus on species richness and abundance but ignore the interactions among different microbial species/populations. However, determining the interactions and their relationships to environmental changes in microbial communities is a grand challenge, primarily due to the lack of information on the network structure among different microbial species/populations. Here, a novel random matrix theory (RMT)-based conceptual framework for identifying functional ecological gene networks (fEGNs) is developed with the high throughput functional gene array hybridization data from the grassland microbial communities in a long-term FACE (Free Air CO2 Enrichment) experiment. Both fEGNs under elevated CO2 (eCO2) and ambient CO2 (aCO2) possessed general characteristics of many complex systems such as scale-free, small-world, modular and hierarchical. However, the topological structure of the fEGNs is distinctly different between eCO2 and aCO2, suggesting that eCO2 dramatically altered the interactions among different microbial functional groups/populations. In addition, the changes in network structure were significantly correlated with soil carbon and nitrogen dynamics, and plant productivity, indicating the potential importance of network interactions in ecosystem functioning. Elucidating network interactions in microbial communities and their responses to environmental changes are fundamentally important for research in microbial ecology, systems microbiology, and global change.

  14. Interactive Land Use-Climate Change Predictions in West Africa: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Wang, G.; Ahmed, K. F.; You, L.; Koo, J.

    2013-12-01

    Land use changes constitute an important regional climate change forcing that modifies the greenhouse gas induced future climate changes. At the same time, climate change is an important driver for land use changes, although it is unclear how important this impact might be relative to the impact of socio-economic factors on future land use. Using West Africa as an example, this study examines the importance of considering land use-climate change interactions in decadal predictions for future land use and climate changes, and thus assess whether there is a strong need to incorporate land use modeling into earth system models. Specifically, we evaluate the impact of projected climate changes from a regional climate model (RegCM4-CLM4) on crop yields using the crop model DSSAT, and assess the need for future land use changes by combining crop yield changes with demand for local productions predicted based on socio-economic drivers using an economic model (IFPRI's IMPACT model). For this preliminary assessment, a simple land use allocation approach is used, which favors agricultural expansion over intensification in order to provide an upper limit for land use changes. As a first test, the RCP8.5 mid-century climate projected by the NCAR CESM model is used as the future climate boundary conditions to drive the regional climate model. The impact of considering the land use-climate change interactions will be evaluated based on the differences in projected climate changes between two types of simulations: one that considers land use changes driven by both climate-induced crop yield changes and socioeconomic factors, and one that considers land use changes driven solely by socioeconomic factors.

  15. Interactions between above- and belowground organisms modified in climate change experiments

    NASA Astrophysics Data System (ADS)

    Stevnbak, Karen; Scherber, Christoph; Gladbach, David J.; Beier, Claus; Mikkelsen, Teis N.; Christensen, Søren

    2012-11-01

    Climate change has been shown to affect ecosystem process rates and community composition, with direct and indirect effects on belowground food webs. In particular, altered rates of herbivory under future climate can be expected to influence above-belowground interactions. Here, we use a multifactor, field-scale climate change experiment and independently manipulate atmospheric CO2 concentration, air and soil temperature and drought in all combinations since 2005. We show that changes in these factors modify the interaction between above- and belowground organisms. We use an insect herbivore to experimentally increase aboveground herbivory in grass phytometers exposed to all eight combinations of climate change factors for three years. Aboveground herbivory increased the abundance of belowground protozoans, microbial growth and microbial nitrogen availability. Increased CO2 modified these links through a reduction in herbivory and cascading effects through the soil food web. Interactions between CO2, drought and warming can affect belowground protozoan abundance. Our findings imply that climate change affects aboveground-belowground interactions through changes in nutrient availability.

  16. Robust sensorimotor representation to physical interaction changes in humanoid motion learning.

    PubMed

    Shimizu, Toshihiko; Saegusa, Ryo; Ikemoto, Shuhei; Ishiguro, Hiroshi; Metta, Giorgio

    2015-05-01

    This paper proposes a learning from demonstration system based on a motion feature, called phase transfer sequence. The system aims to synthesize the knowledge on humanoid whole body motions learned during teacher-supported interactions, and apply this knowledge during different physical interactions between a robot and its surroundings. The phase transfer sequence represents the temporal order of the changing points in multiple time sequences. It encodes the dynamical aspects of the sequences so as to absorb the gaps in timing and amplitude derived from interaction changes. The phase transfer sequence was evaluated in reinforcement learning of sitting-up and walking motions conducted by a real humanoid robot and compatible simulator. In both tasks, the robotic motions were less dependent on physical interactions when learned by the proposed feature than by conventional similarity measurements. Phase transfer sequence also enhanced the convergence speed of motion learning. Our proposed feature is original primarily because it absorbs the gaps caused by changes of the originally acquired physical interactions, thereby enhancing the learning speed in subsequent interactions. PMID:25029488

  17. Large-scale ocean circulation-cloud interactions reduce the pace of transient climate change

    NASA Astrophysics Data System (ADS)

    Trossman, D. S.; Palter, J. B.; Merlis, T. M.; Huang, Y.; Xia, Y.

    2016-04-01

    Changes to the large-scale oceanic circulation are thought to slow the pace of transient climate change due, in part, to their influence on radiative feedbacks. Here we evaluate the interactions between CO2-forced perturbations to the large-scale ocean circulation and the radiative cloud feedback in a climate model. Both the change of the ocean circulation and the radiative cloud feedback strongly influence the magnitude and spatial pattern of surface and ocean warming. Changes in the ocean circulation reduce the amount of transient global warming caused by the radiative cloud feedback by helping to maintain low cloud coverage in the face of global warming. The radiative cloud feedback is key in affecting atmospheric meridional heat transport changes and is the dominant radiative feedback mechanism that responds to ocean circulation change. Uncertainty in the simulated ocean circulation changes due to CO2 forcing may contribute a large share of the spread in the radiative cloud feedback among climate models.

  18. INTERACTIVE EFFECTS OF OZONE DEPLETION AND CLIMATE CHANGE ON BIOGEOCHEMICAL CYCLES

    EPA Science Inventory

    The effects of ozone depletion on global biogeochemical cycles, via increased UV-B radiation at the Earth's surface, have continued to be documented over the past 4 years. In this report we also document various effects of UV-B that interact with global climate change because the...

  19. ENVIRONMENTAL EFFECTS OF OZONE DEPLETION AND ITS INTERACTIONS WITH CLIMATE CHANGE: PROGRESS REPORT 2003

    EPA Science Inventory

    The measures needed for the protection of the Earth's ozone layer are decided regularly by the Parties to the Montreal Protocol. A section of this progress report focuses on the interactive effects of climate change and ozone depletion on biogeochemical cycles.

  20. Predictors of Change in Stress, Interaction Styles, and Depression in Parents of Toddlers with Autism

    ERIC Educational Resources Information Center

    Trocchio, Jennie S.

    2013-01-01

    The purpose of this study was to identify the predictors of change in parental stress (including parent and child factors), depression, and interaction style in parents of toddlers with Autism Spectrum Disorders (ASD), exposed to two types of early intervention (EI) programs, PLAY and Community Standard (CS). This study utilized secondary data of…

  1. INTERACTIVE EFFECTS OF SOLAR UV RADIATION AND CLIMATE CHANGE ON BIOGEOCHEMICAL CYCLING

    EPA Science Inventory

    This paper assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are o...

  2. INTERACTIONS OF CHANGING CLIMATE AND ULTRAVIOLET RADIATION IN AQUATIC AND TERRESTRIAL BIOGEOCHEMICAL CYCLES

    EPA Science Inventory

    During the past decade interest has developed in the interactive effects of climate change and UV radiation on aquatic and terrestrial biogeochemical cycles. This talk used selected case studies to illustrate approaches that are being used to investigate these intriguing processe...

  3. Learning as Longitudinal Interactional Change: From "Other"-Repair to "Self"-Repair in Physiotherapy Treatment

    ERIC Educational Resources Information Center

    Martin, Cathrin; Sahlstrom, Fritjof

    2010-01-01

    The aims of this article are to address how learning is constituted and can be studied as a phenomenon in interaction and to discuss how teaching and learning are related. Theoretically, the article argues for and discusses constraints and affordances for relating sociocultural understandings of learning as changing participation to "conversation…

  4. SMART Moves? A Case Study of One Teacher's Pedagogical Change through Use of the Interactive Whiteboard

    ERIC Educational Resources Information Center

    Mohon, Elizabeth H.

    2008-01-01

    This case study investigates how the use of an interactive whiteboard (IWB) leads to pedagogical change within a UK secondary school classroom. A teacher's experiences as recorded in a reflective journal, and the responses of students as recorded in a questionnaire, are set within the context of rhetoric about the value of IWBs. It is argued that…

  5. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2015

    EPA Science Inventory

    The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, bi...

  6. The Interactions between Problem Solving and Conceptual Change: System Dynamic Modelling as a Platform for Learning

    ERIC Educational Resources Information Center

    Lee, Chwee Beng

    2010-01-01

    This study examines the interactions between problem solving and conceptual change in an elementary science class where students build system dynamic models as a form of problem representations. Through mostly qualitative findings, we illustrate the interplay of three emerging intervening conditions (epistemological belief, structural knowledge…

  7. For Parents: Recognizing and Changing Inappropriate Services through an Interactional Approach.

    ERIC Educational Resources Information Center

    Kitano, Margie K.; LeVine, Elaine S.

    1989-01-01

    The article provides parents with specific strategies, based on an interactional model, for working effectively with schools to ensure the best possible services for the gifted child. Major steps include recognizing the need for intervention, developing parent-school partnerships for change, and monitoring progress. (Author/DB)

  8. Proteomics changes during the incompatible interaction between cowpea and Colletotrichum gloeosporioides (Penz.) Penz and Sacc.

    PubMed

    Moura, Hudson Fernando N; Vasconcelos, Ilka M; Souza, Carlos Eduardo A; Silva, Fredy D A; Moreno, Frederico B M B; Lobo, Marina D P; Monteiro-Moreira, Ana C O; Moura, Arlindo A; Costa, José H; Oliveira, José Tadeu A

    2014-03-01

    Anthracnose represents an important disease of cowpea [Vigna unguiculata L. (Walp.)] caused by the hemibiothrophic fungus Colletotrichum gloeosporioides that drastically reduces cowpea field production. In this study we investigated some biochemical aspects underlying the incompatible interaction between a resistant cowpea genotype and C. gloeosporioides using a proteomic approach. Analyses of two-dimensional gel electrophoresis patterns and protein identification indicate C. gloeosporioides infection-dependent cowpea leaf proteome changes associated with metabolism, photosynthesis, response to stress, oxidative burst and scavenging, defense signaling, and pathogenesis-related proteins. Moreover the C. gloeosporioides responsive proteins interaction network in cowpea revealed the interconnected modulation of key cellular processes involving particularly antioxidants proteins, photosynthetic apparatus forming proteins and proteins of the energetic metabolism that interact with each other suggesting that their expression changes are also important for resistance of cowpea to C. gloeosporioides. PMID:24467908

  9. Soil biotic interactions and climate change: consequences for carbon cycle feedbacks

    NASA Astrophysics Data System (ADS)

    Bardgett, Richard

    2015-04-01

    There is currently much interest in understanding the biological mechanisms that regulate carbon exchanges between land and atmosphere, and how these exchanges respond to climate change. Climate change impacts on biogeochemical cycles via a variety of mechanisms; but there is now mounting evidence that biotic interactions between plants and diverse soil communities play a major role in determining carbon cycle responses to climate change across a range of spatial and temporal scales. Over seasonal and annual timescales, climate change impacts the growth and physiology of plants and their roots, with knock on effects for the activity of soil biota and carbon transformations; in the longer term, over tens to hundreds of years, climate change can cause shifts in community composition, and species range expansions and contractions, with cascading impacts on belowground communities and carbon cycling in soil. These responses have local and, potentially, global scale implications for carbon cycle feedbacks. In this talk, I will draw on recent research to illustrate this hierarchy of plant-soil feedback responses to climate change, the mechanisms involved, and consequences for the carbon cycle at local and global scales. I will also discuss how such knowledge on plant-soil interactions might be harnessed to inform management strategies for soil carbon sequestration and mitigation of climate change, and identify some major research challenges for the future.

  10. Effects of interactive global changes on methane uptake in an annual grassland

    NASA Astrophysics Data System (ADS)

    Blankinship, Joseph C.; Brown, Jamie R.; Dijkstra, Paul; Hungate, Bruce A.

    2010-06-01

    The future size of the terrestrial methane (CH4) sink of upland soils remains uncertain, along with potential feedbacks to global warming. Much of the uncertainty lies in our lack of knowledge about potential interactive effects of multiple simultaneous global environmental changes. Field CH4 fluxes and laboratory soil CH4 consumption were measured five times during 3 consecutive years in a California annual grassland exposed to 8 years of the full factorial combination of ambient and elevated levels of precipitation, temperature, atmospheric CO2 concentration, and N deposition. Across all sampling dates and treatments, increased precipitation caused a 61% reduction in field CH4 uptake. However, this reduction depended quantitatively on other global change factors. Higher precipitation reduced CH4 uptake when temperature or N deposition (but not both) increased, and under elevated CO2 but only late in the growing season. Warming alone also decreased CH4 uptake early in the growing season, which was partly explained by a decrease in laboratory soil CH4 consumption. Atmospheric CH4 models likely need to incorporate nonadditive interactions, seasonal interactions, and interactions between methanotrophy and methanogenesis. Despite the complexity of interactions we observed in this multifactor experiment, the outcome agrees with results from single-factor experiments: an increased terrestrial CH4 sink appears less likely than a reduced one.

  11. Biotic interactions mediate the expansion of black mangrove (Avicennia germinans) into salt marshes under climate change.

    PubMed

    Guo, Hongyu; Zhang, Yihui; Lan, Zhenjiang; Pennings, Steven C

    2013-09-01

    Many species are expanding their distributions to higher latitudes due to global warming. Understanding the mechanisms underlying these distribution shifts is critical for better understanding the impacts of climate changes. The climate envelope approach is widely used to model and predict species distribution shifts with changing climates. Biotic interactions between species, however, may also influence species distributions, and a better understanding of biotic interactions could improve predictions based solely on climate envelope models. Along the northern Gulf of Mexico coast, USA, subtropical black mangrove (Avicennia germinans) at the northern limit of its distribution grows sympatrically with temperate salt marsh plants in Florida, Louisiana, and Texas. In recent decades, freeze-free winters have led to an expansion of black mangrove into salt marshes. We examined how biotic interactions between black mangrove and salt marsh vegetation along the Texas coast varied across (i) a latitudinal gradient (associated with a winter-temperature gradient); (ii) the elevational gradient within each marsh (which creates different marsh habitats); and (iii) different life history stages of black mangroves (seedlings vs. juvenile trees). Each of these variables affected the strength or nature of biotic interactions between black mangrove and salt marsh vegetation: (i) Salt marsh vegetation facilitated black mangrove seedlings at their high-latitude distribution limit, but inhibited black mangrove seedlings at lower latitudes; (ii) mangroves performed well at intermediate elevations, but grew and survived poorly in high- and low-marsh habitats; and (iii) the effect of salt marsh vegetation on black mangroves switched from negative to neutral as black mangroves grew from seedlings into juvenile trees. These results indicate that the expansion of black mangroves is mediated by complex biotic interactions. A better understanding of the impacts of climate change on ecological

  12. Genetic interactions within inositol-related pathways are associated with longitudinal changes in ventricle size

    PubMed Central

    Koran, Mary Ellen I.; Hohman, Timothy J.; Meda, Shashwath A.; Thornton-Wells, Tricia A.

    2013-01-01

    The genetic etiology of late onset Alzheimer disease (LOAD) has proven complex, involving clinical and genetic heterogeneity and gene-gene interactions. Recent genome wide association studies (GWAS) in LOAD have led to the discovery of novel genetic risk factors; however, the investigation of gene-gene interactions has been limited. Conventional genetic studies often use binary disease status as the primary phenotype, but for complex brain-based diseases, neuroimaging data can serve as quantitative endophenotypes that correlate with disease status and closely reflect pathological changes. In the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort, we tested for association of genetic interactions with longitudinal MRI measurements of the inferior lateral ventricles (ILVs), which have repeatedly shown a relationship to LOAD status and progression. We performed linear regression to evaluate the ability of pathway-derived SNP-SNP pairs to predict the slope of change in volume of the ILVs. After Bonferroni correction, we identified four significant interactions in the right ILV (RILV) corresponding to gene-gene pairs SYNJ2-PI4KA, PARD3-MYH2, PDE3A-ABHD12B and OR2L13-PRKG1 and one significant interaction in the left ILV (LILV) corresponding to SYNJ2-PI4KA. The SNP-SNP interaction corresponding to SYNJ2-PI4KA was identical in the RILV and LILV and was the most significant interaction in each (RILV: p=9.10×10−12; LILV: p=8.20×10−13). Both genes belong to the inositol phosphate signaling pathway which has been previously associated with neurodegeneration in AD and we discuss the possibility that perturbation of this pathway results in a down-regulation of the Akt cell survival pathway and, thereby, decreased neuronal survival, as reflected by increased volume of the ventricles. PMID:24077433

  13. Interactive Change Detection Using High Resolution Remote Sensing Images Based on Active Learning with Gaussian Processes

    NASA Astrophysics Data System (ADS)

    Ru, Hui; Yu, Huai; Huang, Pingping; Yang, Wen

    2016-06-01

    Although there have been many studies for change detection, the effective and efficient use of high resolution remote sensing images is still a problem. Conventional supervised methods need lots of annotations to classify the land cover categories and detect their changes. Besides, the training set in supervised methods often has lots of redundant samples without any essential information. In this study, we present a method for interactive change detection using high resolution remote sensing images with active learning to overcome the shortages of existing remote sensing image change detection techniques. In our method, there is no annotation of actual land cover category at the beginning. First, we find a certain number of the most representative objects in unsupervised way. Then, we can detect the change areas from multi-temporal high resolution remote sensing images by active learning with Gaussian processes in an interactive way gradually until the detection results do not change notably. The artificial labelling can be reduced substantially, and a desirable detection result can be obtained in a few iterations. The experiments on Geo-Eye1 and WorldView2 remote sensing images demonstrate the effectiveness and efficiency of our proposed method.

  14. Interactive effects of global climate change and pollution on marine microbes: the way ahead

    PubMed Central

    Coelho, Francisco J R C; Santos, Ana L; Coimbra, Joana; Almeida, Adelaide; Cunha, Ângela; Cleary, Daniel F R; Calado, Ricardo; Gomes, Newton C M

    2013-01-01

    Global climate change has the potential to seriously and adversely affect marine ecosystem functioning. Numerous experimental and modeling studies have demonstrated how predicted ocean acidification and increased ultraviolet radiation (UVR) can affect marine microbes. However, researchers have largely ignored interactions between ocean acidification, increased UVR and anthropogenic pollutants in marine environments. Such interactions can alter chemical speciation and the bioavailability of several organic and inorganic pollutants with potentially deleterious effects, such as modifying microbial-mediated detoxification processes. Microbes mediate major biogeochemical cycles, providing fundamental ecosystems services such as environmental detoxification and recovery. It is, therefore, important that we understand how predicted changes to oceanic pH, UVR, and temperature will affect microbial pollutant detoxification processes in marine ecosystems. The intrinsic characteristics of microbes, such as their short generation time, small size, and functional role in biogeochemical cycles combined with recent advances in molecular techniques (e.g., metagenomics and metatranscriptomics) make microbes excellent models to evaluate the consequences of various climate change scenarios on detoxification processes in marine ecosystems. In this review, we highlight the importance of microbial microcosm experiments, coupled with high-resolution molecular biology techniques, to provide a critical experimental framework to start understanding how climate change, anthropogenic pollution, and microbiological interactions may affect marine ecosystems in the future. PMID:23789087

  15. Adaptation of mammalian host-pathogen interactions in a changing arctic environment

    PubMed Central

    2011-01-01

    Many arctic mammals are adapted to live year-round in extreme environments with low winter temperatures and great seasonal variations in key variables (e.g. sunlight, food, temperature, moisture). The interaction between hosts and pathogens in high northern latitudes is not very well understood with respect to intra-annual cycles (seasons). The annual cycles of interacting pathogen and host biology is regulated in part by highly synchronized temperature and photoperiod changes during seasonal transitions (e.g., freezeup and breakup). With a warming climate, only one of these key biological cues will undergo drastic changes, while the other will remain fixed. This uncoupling can theoretically have drastic consequences on host-pathogen interactions. These poorly understood cues together with a changing climate by itself will challenge host populations that are adapted to pathogens under the historic and current climate regime. We will review adaptations of both host and pathogens to the extreme conditions at high latitudes and explore some potential consequences of rapid changes in the Arctic. PMID:21392401

  16. Pathways of Understanding: the Interactions of Humanity and Global Environmental Change

    NASA Technical Reports Server (NTRS)

    Jacobson, Harold K.; Katzenberger, John; Lousma, Jack; Mooney, Harold A.; Moss, Richard H.; Kuhn, William; Luterbacher, Urs; Wiegandt, Ellen

    1992-01-01

    How humans, interacting within social systems, affect and are affected by global change is explored. Recognizing the impact human activities have on the environment and responding to the need to document the interactions among human activities, the Consortium for International Earth Science Information Network (CIESIN) commissioned a group of 12 scientists to develop a framework illustrating the key human systems that contribute to global change. This framework, called the Social Process Diagram, will help natural and social scientists, educators, resource managers and policy makers envision and analyze how human systems interact among themselves and with the natural system. The Social Process Diagram consists of the following blocks that constitute the Diagram's structural framework: (1) fund of knowledge and experience; (2) preferences and expectations; (3) factors of production and technology; (4) population and social structure; (5) economic systems; (6) political systems and institutions; and (7) global scale environmental processes. To demonstrate potential ways the Diagram can be used, this document includes 3 hypothetical scenarios of global change issues: global warming and sea level rise; the environmental impact of human population migration; and energy and the environment. These scenarios demonstrate the Diagram's usefulness for visualizing specific processes that might be studied to evaluate a particular global change issues. The scenario also shows that interesting and unanticipated questions may emerge as links are explored between categories on the Diagram.

  17. Plant response to climate change varies with topography, interactions with neighbors, and ecotype.

    PubMed

    Liancourt, Pierre; Spence, Laura A; Song, Daniel S; Lkhagva, Ariuntsetseg; Sharkhuu, Anarmaa; Boldgiv, Bazartseren; Helliker, Brent R; Petraitis, Peter S; Casper, Brenda B

    2013-02-01

    Predicting the future of any given species represents an unprecedented challenge in light of the many environmental and biological factors that affect organismal performance and that also interact with drivers of global change. In a three-year experiment set in the Mongolian steppe, we examined the response of the common grass Festuca lenensis to manipulated temperature and water while controlling for topographic variation, plant-plant interactions, and ecotypic differentiation. Plant survival and growth responses to a warmer, drier climate varied within the landscape. Response to simulated increased precipitation occurred only in the absence of neighbors, demonstrating that plant-plant interactions can supersede the effects of climate change. F. lenensis also showed evidence of local adaptation in populations that were only 300 m apart. Individuals from the steep and dry upper slope showed a higher stress/drought tolerance, whereas those from the more productive lower slope showed a higher biomass production and a greater ability to cope with competition. Moreover, the response of this species to increased precipitation was ecotype specific, with water addition benefiting only the least stress-tolerant ecotype from the lower slope origin. This multifaceted approach illustrates the importance of placing climate change experiments within a realistic ecological and evolutionary framework. Existing sources of variation impacting plant performance may buffer or obscure climate change effects. PMID:23691663

  18. INTERACTIONS BETWEEN CHEMICAL AND CLIMATE STRESSORS: A ROLE FOR MECHANISTIC TOXICOLOGY IN ASSESSING CLIMATE CHANGE RISKS

    PubMed Central

    Hooper, Michael J; Ankley, Gerald T; Cristol, Daniel A; Maryoung, Lindley A; Noyes, Pamela D; Pinkerton, Kent E

    2013-01-01

    Incorporation of global climate change (GCC) effects into assessments of chemical risk and injury requires integrated examinations of chemical and nonchemical stressors. Environmental variables altered by GCC (temperature, precipitation, salinity, pH) can influence the toxicokinetics of chemical absorption, distribution, metabolism, and excretion as well as toxicodynamic interactions between chemicals and target molecules. In addition, GCC challenges processes critical for coping with the external environment (water balance, thermoregulation, nutrition, and the immune, endocrine, and neurological systems), leaving organisms sensitive to even slight perturbations by chemicals when pushed to the limits of their physiological tolerance range. In simplest terms, GCC can make organisms more sensitive to chemical stressors, while alternatively, exposure to chemicals can make organisms more sensitive to GCC stressors. One challenge is to identify potential interactions between nonchemical and chemical stressors affecting key physiological processes in an organism. We employed adverse outcome pathways, constructs depicting linkages between mechanism-based molecular initiating events and impacts on individuals or populations, to assess how chemical- and climate-specific variables interact to lead to adverse outcomes. Case examples are presented for prospective scenarios, hypothesizing potential chemical–GCC interactions, and retrospective scenarios, proposing mechanisms for demonstrated chemical–climate interactions in natural populations. Understanding GCC interactions along adverse outcome pathways facilitates extrapolation between species or other levels of organization, development of hypotheses and focal areas for further research, and improved inputs for risk and resource injury assessments. Environ. Toxicol. Chem. 2013;32:32–48. © 2012 SETAC PMID:23136056

  19. Interactions between chemical and climate stressors: A role for mechanistic toxicology in assessing climate change risks

    USGS Publications Warehouse

    Hooper, Michael J.; Ankley, Gerald T.; Cristol, Daniel A.; Maryoung, Lindley A.; Noyes, Pamela D.; Pinkerton, Kent E.

    2013-01-01

    Incorporation of global climate change (GCC) effects into assessments of chemical risk and injury requires integrated examinations of chemical and nonchemical stressors. Environmental variables altered by GCC (temperature, precipitation, salinity, pH) can influence the toxicokinetics of chemical absorption, distribution, metabolism, and excretion as well as toxicodynamic interactions between chemicals and target molecules. In addition, GCC challenges processes critical for coping with the external environment (water balance, thermoregulation, nutrition, and the immune, endocrine, and neurological systems), leaving organisms sensitive to even slight perturbations by chemicals when pushed to the limits of their physiological tolerance range. In simplest terms, GCC can make organisms more sensitive to chemical stressors, while alternatively, exposure to chemicals can make organisms more sensitive to GCC stressors. One challenge is to identify potential interactions between nonchemical and chemical stressors affecting key physiological processes in an organism. We employed adverse outcome pathways, constructs depicting linkages between mechanism-based molecular initiating events and impacts on individuals or populations, to assess how chemical- and climate-specific variables interact to lead to adverse outcomes. Case examples are presented for prospective scenarios, hypothesizing potential chemical–GCC interactions, and retrospective scenarios, proposing mechanisms for demonstrated chemical–climate interactions in natural populations. Understanding GCC interactions along adverse outcome pathways facilitates extrapolation between species or other levels of organization, development of hypotheses and focal areas for further research, and improved inputs for risk and resource injury assessments.

  20. Climate-chemical interactions and effects of changing atmospheric trace gases

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.; Callis, L.; Cess, R.; Hansen, J.; Isaksen, I.

    1987-01-01

    The paper considers trace gas-climate effects including the greenhouse effect of polyatomic trace gases, the nature of the radiative-chemical interactions, and radiative-dynamical interactions in the stratosphere, and the role of these effects in governing stratospheric climate change. Special consideration is given to recent developments in the investigations of the role of oceans in governing the transient climate responses, and a time-dependent estimate of the potential trace gas warming from the preindustrial era to the early 21st century. The importance of interacting modeling and observational efforts is emphasized. One of the problems remaining on the observational front is the lack of certainty in current estimates of the rate of growth of CO, O3, and NOx; the primary challenge is the design of a strategy that will minimize the sampling errors.

  1. Dynamics of binary and planetary-system interaction with disks - Eccentricity changes

    NASA Technical Reports Server (NTRS)

    Atrymowicz, Pawel

    1992-01-01

    Protostellar and protoplanetary systems, as well as merging galactic nuclei, often interact tidally and resonantly with the astrophysical disks via gravity. Underlying our understanding of the formation processes of stars, planets, and some galaxies is a dynamical theory of such interactions. Its main goals are to determine the geometry of the binary-disk system and, through the torque calculations, the rate of change of orbital elements of the components. We present some recent developments in this field concentrating on eccentricity driving mechanisms in protoplanetary and protobinary systems. In those two types of systems the result of the interaction is opposite. A small body embedded in a disk suffers a decrease of orbital eccentricity, whereas newly formed binary stars surrounded by protostellar disks may undergo a significant orbital evolution increasing their eccentricities.

  2. Protein-Nanoparticle Interaction-Induced Changes in Protein Structure and Aggregation.

    PubMed

    Kim, Yuna; Ko, Sung Min; Nam, Jwa-Min

    2016-07-01

    Large surface area, small size, strong optical properties, controllable structural features, variety of bioconjugation chemistries, and biocompatibility make many different types of nanoparticles (NPs), such as gold NPs, useful for many biological applications, such as biosensing, cellular imaging, disease diagnostics, drug delivery, and therapeutics. Recently, interactions between proteins and NPs have been extensively studied to understand, control, and utilize the interactions involved in biomedical applications of NPs and several biological processes, such as protein aggregation, for many diseases, including Alzheimer's disease. These studies also offer fundamental knowledge on changes in protein structure, protein aggregation mechanisms, and ways to unravel the roles and fates of NPs within the human body. This review focuses on recent studies on the roles and uses of NPs in protein structural changes and aggregation processes. PMID:27062521

  3. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2015.

    PubMed

    2016-02-01

    The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, biogeochemistry, air quality, and materials. The Panels provide a detailed assessment report every four years. The most recent 2014 Quadrennial Assessment by the EEAP was published as a special issue of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). The next Quadrennial Assessment will be published in 2018/2019. In the interim, the EEAP generally produces an annual update or progress report of the relevant scientific findings. The present progress report for 2015 assesses some of the highlights and new insights with regard to the interactive nature of the effects of UV radiation, atmospheric processes, and climate change. PMID:26822392

  4. Novel measure of driver and vehicle interaction demonstrates transient changes related to alerting.

    PubMed

    Brooks, Justin R; Kerick, Scott E; McDowell, Kaleb

    2015-01-01

    Driver behavior and vehicle-road kinematics have been shown to change over prolonged periods of driving; however, the interaction between these two indices has not been examined. Here we develop a measure that examines how drivers turn the steering wheel relative to heading error velocity, which the authors call the relative steering wheel compensation (RSWC). The RSWC transiently changes on a short time scale coincident with a verbal query embedded within the study paradigm. In contrast, more traditional variables are dynamic over longer time scales consistent with previous research. The results suggest drivers alter their behavioral output (steering wheel correction) relative to sensory input (vehicle heading error velocity) on a distinct temporal scale and may reflect an interaction of alerting and control. PMID:25356659

  5. Novel Measure of Driver and Vehicle Interaction Demonstrates Transient Changes Related to Alerting

    PubMed Central

    Brooks, Justin R.; Kerick, Scott E.; McDowell, Kaleb

    2015-01-01

    ABSTRACT Driver behavior and vehicle-road kinematics have been shown to change over prolonged periods of driving; however, the interaction between these two indices has not been examined. Here we develop a measure that examines how drivers turn the steering wheel relative to heading error velocity, which the authors call the relative steering wheel compensation (RSWC). The RSWC transiently changes on a short time scale coincident with a verbal query embedded within the study paradigm. In contrast, more traditional variables are dynamic over longer time scales consistent with previous research. The results suggest drivers alter their behavioral output (steering wheel correction) relative to sensory input (vehicle heading error velocity) on a distinct temporal scale and may reflect an interaction of alerting and control. PMID:25356659

  6. Developmental change and consistency in parental interactions with school-age children who have mental retardation.

    PubMed

    Floyd, F J; Costigan, C L; Phillippe, K A

    1997-05-01

    Developmental changes and within-family consistency in parent-child interactions were examined for mothers and fathers of school-age children (6 to 18 years) with mental retardation. At Time 1 and 18 to 24 months later, 98 families (29 single, 69 two-parent) with a child who had mild or moderate mental retardation completed semi-structured interaction sessions in their homes. As expected, both positive and negative exchanges decreased longitudinally, and cross-sectional comparisons revealed fewer parent commands, less child noncompliance, fewer child negatives, and less parent positive reciprocity with older children. Most behaviors were highly consistent between family members and stable over time. Findings were discussed in relation to parental responsiveness to developmental changes for the child and the coherence of family relationships over time. PMID:9152474

  7. Changes in thalamo-frontal interaction under different levels of anesthesia in rats.

    PubMed

    Shin, Teo Jeon; Cho, Dongrae; Ham, Jinsil; Choi, Dong-Hyuk; Kim, Seonghyun; Jeong, Seongwook; Kim, Hyoung-Ihl; Kim, Jae Gwan; Lee, Boreom

    2016-08-01

    Anesthesia is thought to be mediated by inhibiting the integration of information between different areas of the brain. Long-range thalamo-cortical interaction plays a critical role in inducing anesthesia-related unconsciousness. However, it remains unclear how this interaction change according to anesthetic depth. In this study, we aimed to investigate how different levels of anesthesia affect thalamo-frontal interactions. Prior to the experiment, electrodes were implanted to record local field potentials (LFPs). Isoflurane (ISO) was administered and LFPs were measured in rats from four different brain areas (left frontal, right frontal, left thalamus and right thalamus) at four different anesthesia levels: awake, deep (ISO 2.5vol%), light (ISO 1vol%) and recovery. Spectral granger causality (Spectral-GC) were calculated at the measured areas in accordance with anesthetic levels. Anesthesia led to a decrease in connectivity in the thalamo-frontal direction and an increase in connectivity in the frontal-thalamic direction. The changes in thalamo-frontal functional connectivity were prominent during deep anesthesia at high frequency bands. The connection strengths between the thalamus and the frontal area changed depending on the depth of anesthesia. The relationships between anesthetic levels and thalamo-frontal activity may shed light on the neural mechanism by which different levels of anesthesia act. PMID:27230989

  8. Interactive effects of solar UV radiation and climate change on biogeochemical cycling.

    PubMed

    Zepp, R G; Erickson, D J; Paul, N D; Sulzberger, B

    2007-03-01

    This report assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are often linked to concurrent exposure to UV-A radiation (315-400 nm), which is influenced by global climate change. These interactions involving UV radiation (the combination of UV-B and UV-A) are central to the prediction and evaluation of future Earth environmental conditions. There is increasing evidence that elevated UV-B radiation has significant effects on the terrestrial biosphere with implications for the cycling of carbon, nitrogen and other elements. The cycling of carbon and inorganic nutrients such as nitrogen can be affected by UV-B-mediated changes in communities of soil organisms, probably due to the effects of UV-B radiation on plant root exudation and/or the chemistry of dead plant material falling to the soil. In arid environments direct photodegradation can play a major role in the decay of plant litter, and UV-B radiation is responsible for a significant part of this photodegradation. UV-B radiation strongly influences aquatic carbon, nitrogen, sulfur and metals cycling that affect a wide range of life processes. UV-B radiation changes the biological availability of dissolved organic matter to microorganisms, and accelerates its transformation into dissolved inorganic carbon and nitrogen, including carbon dioxide and ammonium. The coloured part of dissolved organic matter (CDOM) controls the penetration of UV radiation into water bodies, but CDOM is also photodegraded by solar UV radiation. Changes in CDOM influence the penetration of UV radiation into water bodies with major consequences for aquatic biogeochemical processes. Changes in aquatic primary productivity and decomposition due to climate-related changes in circulation and nutrient supply occur concurrently with

  9. Minor Allele Frequency Changes the Nature of Genotype by Environment Interactions.

    PubMed

    Verhulst, Brad; Neale, Michael C

    2016-09-01

    In the classical twin study, phenotypic variation is often partitioned into additive genetic (A), common (C) and specific environment (E) components. From genetical theory, the outcome of genotype by environment interaction is expected to inflate A when the interacting factor is shared (i.e., C) between the members of a twin pair. We show that estimates of both A and C can be inflated. When the shared interacting factor changes the size of the difference between homozygotes' means, the expected sibling or DZ twin correlation is .5 if and only if the minor allele frequency (MAF) is .5; otherwise the expected DZ correlation is greater than this value, consistent (and confounded) with some additional effect of C. This result is considered in the light of the distribution of minor allele frequencies for polygenic traits. Also discussed is whether such interactions take place at the locus level or affect an aggregated biological structure or system. Interactions with structures or endophenotypes that result from the aggregated effects of many loci will generally emerge as part of the A estimate. PMID:27105628

  10. Enculturating science: Community-centric design of behavior change interactions for accelerating health impact.

    PubMed

    Kumar, Vishwajeet; Kumar, Aarti; Ghosh, Amit Kumar; Samphel, Rigzin; Yadav, Ranjanaa; Yeung, Diana; Darmstadt, Gary L

    2015-08-01

    Despite significant advancements in the scientific evidence base of interventions to improve newborn survival, we have not yet been able to "bend the curve" to markedly accelerate global rates of reduction in newborn mortality. The ever-widening gap between discovery of scientific best practices and their mass adoption by families (the evidence-practice gap) is not just a matter of improving the coverage of health worker-community interactions. The design of the interactions themselves must be guided by sound behavioral science approaches such that they lead to mass adoption and impact at a large scale. The main barrier to the application of scientific approaches to behavior change is our inability to "unbox" the "black box" of family health behaviors in community settings. The authors argue that these are not black boxes, but in fact thoughtfully designed community systems that have been designed and upheld, and have evolved over many years keeping in mind a certain worldview and a common social purpose. An empathetic understanding of these community systems allows us to deconstruct the causal pathways of existing behaviors, and re-engineer them to achieve desired outcomes. One of the key reasons for the failure of interactions to translate into behavior change is our failure to recognize that the content, context, and process of interactions need to be designed keeping in mind an organized community system with a very different worldview and beliefs. In order to improve the adoption of scientific best practices by communities, we need to adapt them to their culture by leveraging existing beliefs, practices, people, context, and skills. The authors present a systems approach for community-centric design of interactions, highlighting key principles for achieving intrinsically motivated, sustained change in social norms and family health behaviors, elucidated with progressive theories from systems thinking, management sciences, cross-cultural psychology, learning

  11. Interactive effects of global change factors on soil respiration and its components: a meta-analysis.

    PubMed

    Zhou, Lingyan; Zhou, Xuhui; Shao, Junjiong; Nie, Yuanyuan; He, Yanghui; Jiang, Liling; Wu, Zhuoting; Hosseini Bai, Shahla

    2016-09-01

    As the second largest carbon (C) flux between the atmosphere and terrestrial ecosystems, soil respiration (Rs) plays vital roles in regulating atmospheric CO2 concentration ([CO2 ]) and climatic dynamics in the earth system. Although numerous manipulative studies and a few meta-analyses have been conducted to determine the responses of Rs and its two components [i.e., autotrophic (Ra) and heterotrophic (Rh) respiration] to single global change factors, the interactive effects of the multiple factors are still unclear. In this study, we performed a meta-analysis of 150 multiple-factor (≥2) studies to examine the main and interactive effects of global change factors on Rs and its two components. Our results showed that elevated [CO2 ] (E), nitrogen addition (N), irrigation (I), and warming (W) induced significant increases in Rs by 28.6%, 8.8%, 9.7%, and 7.1%, respectively. The combined effects of the multiple factors, EN, EW, DE, IE, IN, IW, IEW, and DEW, were also significantly positive on Rs to a greater extent than those of the single-factor ones. For all the individual studies, the additive interactions were predominant on Rs (90.6%) and its components (≈70.0%) relative to synergistic and antagonistic ones. However, the different combinations of global change factors (e.g., EN, NW, EW, IW) indicated that the three types of interactions were all important, with two combinations for synergistic effects, two for antagonistic, and five for additive when at least eight independent experiments were considered. In addition, the interactions of elevated [CO2 ] and warming had opposite effects on Ra and Rh, suggesting that different processes may influence their responses to the multifactor interactions. Our study highlights the crucial importance of the interactive effects among the multiple factors on Rs and its components, which could inform regional and global models to assess the climate-biosphere feedbacks and improve predictions of the future states of the

  12. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions.

    PubMed

    Baert, Jan M; Janssen, Colin R; Sabbe, Koen; De Laender, Frederik

    2016-01-01

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity-ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity-productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity-productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions. PMID:27534986

  13. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions

    PubMed Central

    Baert, Jan M.; Janssen, Colin R.; Sabbe, Koen; De Laender, Frederik

    2016-01-01

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity–ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity–productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity–productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions. PMID:27534986

  14. Dynamic changes in brain aromatase activity following sexual interactions in males: where, when and why?

    PubMed Central

    de Bournonville, Catherine; Dickens, Molly J.; Ball, Gregory F.; Balthazart, Jacques; Cornil, Charlotte A.

    2012-01-01

    Summary It is increasingly recognized that estrogens produce rapid and transient effects at many neural sites ultimately impacting physiological and behavioral endpoints. The ability of estrogens to acutely regulate cellular processes implies that their concentration should also be rapidly fine-tuned. Accordingly, rapid changes in the catalytic activity of aromatase, the limiting enzyme for estrogen synthesis, have been identified that could serve as a regulatory mechanism of local estrogen concentrations. However, the precise anatomical localization, time-course, triggering stimuli and functional significance of these enzymatic changes in vivo are not well understood. To address these issues as to where, when and why aromatase activity (AA) rapidly changes after sexual interactions, AA was assayed in six populations of aromatase-expressing cells microdissected from the brain of male quail that experienced varying durations of visual exposure to or copulation with a female. Sexual interactions resulted in a rapid AA inhibition. This inhibition occurred in specific brain regions (including the medial preoptic nucleus), in a context-dependent fashion and time-scale suggestive of post-translational modifications of the enzyme. Interestingly, the enzymatic fluctuations occurring in the preoptic area followed rather than preceded copulation and were tied specifically to the female's presence. This pattern of enzymatic changes suggests that rapid estrogen effects are important during the motivational phase of the behavior to trigger physiological events essential to activate mate search and copulation. PMID:22999655

  15. New insights into the molecular mechanisms of biomembrane structural changes and interactions by optical biosensor technology.

    PubMed

    Lee, Tzong-Hsien; Hirst, Daniel J; Aguilar, Marie-Isabel

    2015-09-01

    Biomolecular-membrane interactions play a critical role in the regulation of many important biological processes such as protein trafficking, cellular signalling and ion channel formation. Peptide/protein-membrane interactions can also destabilise and damage the membrane which can lead to cell death. Characterisation of the molecular details of these binding-mediated membrane destabilisation processes is therefore central to understanding cellular events such as antimicrobial action, membrane-mediated amyloid aggregation, and apoptotic protein induced mitochondrial membrane permeabilisation. Optical biosensors have provided a unique approach to characterising membrane interactions allowing quantitation of binding events and new insight into the kinetic mechanism of these interactions. One of the most commonly used optical biosensor technologies is surface plasmon resonance (SPR) and there have been an increasing number of studies reporting the use of this technique for investigating biophysical analysis of membrane-mediated events. More recently, a number of new optical biosensors based on waveguide techniques have been developed, allowing membrane structure changes to be measured simultaneously with mass binding measurements. These techniques include dual polarisation interferometry (DPI), plasmon waveguide resonance spectroscopy (PWR) and optical waveguide light mode spectroscopy (OWLS). These techniques have expanded the application of optical biosensors to allow the analysis of membrane structure changes during peptide and protein binding. This review provides a theoretical and practical overview of the application of biosensor technology with a specific focus on DPI, PWR and OWLS to study biomembrane-mediated events and the mechanism of biomembrane disruption. This article is part of a Special Issue entitled: Lipid-protein interactions. PMID:26009270

  16. The role of interactions in a world implementing adaptation and mitigation solutions to climate change.

    PubMed

    Warren, Rachel

    2011-01-13

    The papers in this volume discuss projections of climate change impacts upon humans and ecosystems under a global mean temperature rise of 4°C above preindustrial levels. Like most studies, they are mainly single-sector or single-region-based assessments. Even the multi-sector or multi-region approaches generally consider impacts in sectors and regions independently, ignoring interactions. Extreme weather and adaptation processes are often poorly represented and losses of ecosystem services induced by climate change or human adaptation are generally omitted. This paper addresses this gap by reviewing some potential interactions in a 4°C world, and also makes a comparison with a 2°C world. In a 4°C world, major shifts in agricultural land use and increased drought are projected, and an increased human population might increasingly be concentrated in areas remaining wet enough for economic prosperity. Ecosystem services that enable prosperity would be declining, with carbon cycle feedbacks and fire causing forest losses. There is an urgent need for integrated assessments considering the synergy of impacts and limits to adaptation in multiple sectors and regions in a 4°C world. By contrast, a 2°C world is projected to experience about one-half of the climate change impacts, with concomitantly smaller challenges for adaptation. Ecosystem services, including the carbon sink provided by the Earth's forests, would be expected to be largely preserved, with much less potential for interaction processes to increase challenges to adaptation. However, demands for land and water for biofuel cropping could reduce the availability of these resources for agricultural and natural systems. Hence, a whole system approach to mitigation and adaptation, considering interactions, potential human and species migration, allocation of land and water resources and ecosystem services, will be important in either a 2°C or a 4°C world. PMID:21115521

  17. Courtship interactions stimulate rapid changes in GnRH synthesis in male ring doves

    PubMed Central

    Mantei, Kristen E.; Ramakrishnan, Selvakumar; Sharp, Peter J.; Buntin, John D.

    2008-01-01

    Many birds and mammals show changes in the hypothalamo-pituitary-gonadal (HPG) axis in response to social or sexual interactions between breeding partners. While alterations in GnRH neuronal activity play an important role in stimulating these changes, it remains unclear if acute behaviorally-induced alterations in GnRH release are accompanied by parallel changes in GnRH synthesis. To investigate this relationship, we examined changes in the activity of GnRH neurons in the brains of male ring doves following brief periods of courtship interactions with females. Such interactions have been previously shown to increase plasma LH in courting male doves at 24 h, but not at 1 h, after pairing with females. In the first study, males allowed to court females for 2 h had 60% more cells that showed immunocytochemical labeling for GnRH-I in the preoptic area (POA) of the hypothalamus than did control males that remained isolated from females. To determine whether an increase in GnRH gene expression preceded this increase in GnRH immunoreactivity in the POA, changes in the number of cells with detectable GnRH-I mRNA in the POA were measured by in situ hybridization following a 1 h period of courtship interactions with females. In this second study, courting males exhibited 40% more cells with GnRH-I in this region than did isolated control males. GnRH-immunoreactive neurons in two other diencephalic regions failed to show these courtship-induced changes. Plasma LH was not elevated after 1 or 2 h of courtship. These results demonstrate that the release of GnRH-I in the POA that is presumably responsible for courtship-induced pituitary and gonadal activation is accompanied by a rapid increase in GnRH synthesis that occurs before plasma LH levels increase. We suggest that this increase in GnRH synthesis is necessary to support the extended period of HPG axis activation that is seen in this species during the 5–10 day period of courtship and nest building activity. PMID

  18. A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing

    PubMed Central

    Chou, Ho-Hsiu; Nguyen, Amanda; Chortos, Alex; To, John W.F.; Lu, Chien; Mei, Jianguo; Kurosawa, Tadanori; Bae, Won-Gyu; Tok, Jeffrey B.-H.; Bao, Zhenan

    2015-01-01

    Some animals, such as the chameleon and cephalopod, have the remarkable capability to change their skin colour. This unique characteristic has long inspired scientists to develop materials and devices to mimic such a function. However, it requires the complex integration of stretchability, colour-changing and tactile sensing. Here we show an all-solution processed chameleon-inspired stretchable electronic skin (e-skin), in which the e-skin colour can easily be controlled through varying the applied pressure along with the applied pressure duration. As such, the e-skin's colour change can also be in turn utilized to distinguish the pressure applied. The integration of the stretchable, highly tunable resistive pressure sensor and the fully stretchable organic electrochromic device enables the demonstration of a stretchable electrochromically active e-skin with tactile-sensing control. This system will have wide range applications such as interactive wearable devices, artificial prosthetics and smart robots. PMID:26300307

  19. A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing

    NASA Astrophysics Data System (ADS)

    Chou, Ho-Hsiu; Nguyen, Amanda; Chortos, Alex; To, John W. F.; Lu, Chien; Mei, Jianguo; Kurosawa, Tadanori; Bae, Won-Gyu; Tok, Jeffrey B.-H.; Bao, Zhenan

    2015-08-01

    Some animals, such as the chameleon and cephalopod, have the remarkable capability to change their skin colour. This unique characteristic has long inspired scientists to develop materials and devices to mimic such a function. However, it requires the complex integration of stretchability, colour-changing and tactile sensing. Here we show an all-solution processed chameleon-inspired stretchable electronic skin (e-skin), in which the e-skin colour can easily be controlled through varying the applied pressure along with the applied pressure duration. As such, the e-skin's colour change can also be in turn utilized to distinguish the pressure applied. The integration of the stretchable, highly tunable resistive pressure sensor and the fully stretchable organic electrochromic device enables the demonstration of a stretchable electrochromically active e-skin with tactile-sensing control. This system will have wide range applications such as interactive wearable devices, artificial prosthetics and smart robots.

  20. Interactions of Mean Climate Change and Climate Variability on Food Security Extremes

    NASA Technical Reports Server (NTRS)

    Ruane, Alexander C.; McDermid, Sonali; Mavromatis, Theodoros; Hudson, Nicholas; Morales, Monica; Simmons, John; Prabodha, Agalawatte; Ahmad, Ashfaq; Ahmad, Shakeel; Ahuja, Laj R.

    2015-01-01

    Recognizing that climate change will affect agricultural systems both through mean changes and through shifts in climate variability and associated extreme events, we present preliminary analyses of climate impacts from a network of 1137 crop modeling sites contributed to the AgMIP Coordinated Climate-Crop Modeling Project (C3MP). At each site sensitivity tests were run according to a common protocol, which enables the fitting of crop model emulators across a range of carbon dioxide, temperature, and water (CTW) changes. C3MP can elucidate several aspects of these changes and quantify crop responses across a wide diversity of farming systems. Here we test the hypothesis that climate change and variability interact in three main ways. First, mean climate changes can affect yields across an entire time period. Second, extreme events (when they do occur) may be more sensitive to climate changes than a year with normal climate. Third, mean climate changes can alter the likelihood of climate extremes, leading to more frequent seasons with anomalies outside of the expected conditions for which management was designed. In this way, shifts in climate variability can result in an increase or reduction of mean yield, as extreme climate events tend to have lower yield than years with normal climate.C3MP maize simulations across 126 farms reveal a clear indication and quantification (as response functions) of mean climate impacts on mean yield and clearly show that mean climate changes will directly affect the variability of yield. Yield reductions from increased climate variability are not as clear as crop models tend to be less sensitive to dangers on the cool and wet extremes of climate variability, likely underestimating losses from water-logging, floods, and frosts.

  1. Climate change affects the outcome of competitive interactions-an application of principal response curves.

    PubMed

    Heegaard, Einar; Vandvik, Vigdis

    2004-05-01

    It has been hypothesised that climate change may affect vegetation by changing the outcome of competitive interactions. We use a space-for-time approach to evaluate this hypothesis in the context of alpine time-of-snowmelt gradients. Principal response curves, a multivariate repeated-measurement analysis technique, are used to analyse for compositional differences in local ridge-to-snowbed gradients among 100 m altitudinal bands from 1,140 to 1,550 m a.s.l., corresponding to a temperature gradient of 2.5 degrees C (local lapse rate is 0.6 degrees C). The interaction between time-of-snowmelt and altitude is strongly significant statistically, indicating that the altitudinal gradient cannot be explained simply by the physiological responses of the species, but that there are also changes in the outcome of competitive interactions. At higher altitudes, there is a decrease in the time-of-snowmelt ranges of species which have intermediate times-of-snowmelt optima, whereas snowbed (chinophilous) species have wider time-of-snowmelt ranges. As snowbed species can survive, grow and reproduce at very early snow-free sites at high altitudes, the most likely explanation for their absence from all but the latest time-of-snowmelt habitats at lower altitudes is competitive exclusion by more vigorous lee-side species. This suggests that with future climate change snowbed species will experience, in addition to habitat fragmentation and reduced size of habitats due to increased temperature and snowmelt, an indirect effect due to competitive exclusion from late-snowmelt sites by species that have their optima outside snowbeds. PMID:15021981

  2. Training mildly handicapped peers to facilitate changes in the social interaction skills of autistic children.

    PubMed Central

    Shafer, M S; Egel, A L; Neef, N A

    1984-01-01

    We evaluated the effects of a peer-training strategy, consisting of direct prompting and modeling, on the occurrence and duration of interactions between autistic students and nonautistic peer-trainers. Data were obtained in both training and generalization settings. The results of a multiple-baseline design across students demonstrated that:the direct prompting procedure produced immediate and substantial increases in the occurrences and durations of positive social interactions between the peer-trainers and autistic students; these increases were maintained across time at levels above baseline during subsequent free-play probes; these findings were judged by teachers to be socially valid; untrained peers increased their interactions with the autistic students in three of the four groups; generalization of behavior change across settings occurred only after specific programming; and interactions between untrained peers and peer-trainers decreased following training. Variables that may account for the results and the implications of these findings for peer-mediated interventions are discussed. PMID:6526767

  3. Thermal acclimation of interactions: differential responses to temperature change alter predator–prey relationship

    PubMed Central

    Grigaltchik, Veronica S.; Ward, Ashley J. W.; Seebacher, Frank

    2012-01-01

    Different species respond differently to environmental change so that species interactions cannot be predicted from single-species performance curves. We tested the hypothesis that interspecific difference in the capacity for thermal acclimation modulates predator–prey interactions. Acclimation of locomotor performance in a predator (Australian bass, Macquaria novemaculeata) was qualitatively different to that of its prey (eastern mosquitofish, Gambusia holbrooki). Warm (25°C) acclimated bass made more attacks than cold (15°C) acclimated fish regardless of acute test temperatures (10–30°C), and greater frequency of attacks was associated with increased prey capture success. However, the number of attacks declined at the highest test temperature (30°C). Interestingly, escape speeds of mosquitofish during predation trials were greater than burst speeds measured in a swimming arena, whereas attack speeds of bass were lower than burst speeds. As a result, escape speeds of mosquitofish were greater at warm temperatures (25°C and 30°C) than attack speeds of bass. The decline in the number of attacks and the increase in escape speed of prey means that predation pressure decreases at high temperatures. We show that differential thermal responses affect species interactions even at temperatures that are within thermal tolerance ranges. This thermal sensitivity of predator–prey interactions can be a mechanism by which global warming affects ecological communities. PMID:22859598

  4. A neurotoxic pesticide changes the outcome of aggressive interactions between native and invasive ants

    PubMed Central

    Barbieri, Rafael F.; Lester, Philip J.; Miller, Alexander S.; Ryan, Ken G.

    2013-01-01

    Neurotoxic pesticides, such as neonicotinoids, negatively affect the cognitive capacity and fitness of non-target species, and could also modify interspecific interactions. We tested whether sublethal contamination with neonicotinoid could affect foraging, colony fitness and the outcome of behavioural interactions between a native (Monomorium antarcticum) and an invasive ant species (Linepithema humile). The foraging behaviour of both ants was not affected by neonicotinoid exposure. Colonies of the invasive species exposed to the neonicotinoid produced significantly fewer brood. In interspecific confrontations, individuals of the native species exposed to the neonicotinoid lowered their aggression towards the invasive species, although their survival probability was not affected. Exposed individuals of the invasive species interacting with non-exposed native ants displayed increased aggression and had their survival probability reduced. Non-exposed individuals of the invasive species were less aggressive but more likely to survive when interacting with exposed native ants. These results suggest that non-target exposure of invaders to neonicotinoids could either increase or decrease the probability of survival according to the exposure status of the native species. Given that, in any community, different species have different food preferences, and thus different exposure to pesticides, non-target exposure could potentially change the dynamics of communities and influence invasion success. PMID:24266038

  5. Sequence-dependent rotation axis changes and interaction torque use in overarm throwing.

    PubMed

    Hansen, Clint; Rezzoug, Nasser; Gorce, Philippe; Venture, Gentiane; Isableu, Brice

    2016-01-01

    We examined the role of rotation axes during an overarm throwing task. Participants performed such task and were asked to throw a ball at maximal velocity at a target. The purpose of this study was to examine whether the minimum inertia axis would be exploited during the throwing phases, a time when internal-external rotations of the shoulder are particularly important. A motion capture system was used to evaluate the performance and to compute the potential axes of rotation (minimum inertia axis, shoulder-centre of mass axis and the shoulder-elbow axis). More specifically, we investigated whether a velocity-dependent change in rotational axes can be observed in the different throwing phases and whether the control obeys the principle of minimum inertia resistance. Our results showed that the limbs' rotational axis mainly coincides with the minimum inertia axis during the cocking phase and with the shoulder-elbow axis during the acceleration phase. Besides these rotation axes changes, the use of interaction torque is also sequence-dependent. The sequence-dependent rotation axes changes associated with the use of interaction torque during the acceleration phase could be a key factor in the production of hand velocity at ball release. PMID:26264114

  6. Metabolic Changes Following Perinatal Asphyxia: Role of Astrocytes and Their Interaction with Neurons

    PubMed Central

    Logica, Tamara; Riviere, Stephanie; Holubiec, Mariana I.; Castilla, Rocío; Barreto, George E.; Capani, Francisco

    2016-01-01

    Perinatal Asphyxia (PA) represents an important cause of severe neurological deficits including delayed mental and motor development, epilepsy, major cognitive deficits and blindness. The interaction between neurons, astrocytes and endothelial cells plays a central role coupling energy supply with changes in neuronal activity. Traditionally, experimental research focused on neurons, whereas astrocytes have been more related to the damage mechanisms of PA. Astrocytes carry out a number of functions that are critical to normal nervous system function, including uptake of neurotransmitters, regulation of pH and ion concentrations, and metabolic support for neurons. In this work, we aim to review metabolic neuron-astrocyte interactions with the purpose of encourage further research in this area in the context of PA, which is highly complex and its mechanisms and pathways have not been fully elucidated to this day. PMID:27445788

  7. Metabolic Changes Following Perinatal Asphyxia: Role of Astrocytes and Their Interaction with Neurons.

    PubMed

    Logica, Tamara; Riviere, Stephanie; Holubiec, Mariana I; Castilla, Rocío; Barreto, George E; Capani, Francisco

    2016-01-01

    Perinatal Asphyxia (PA) represents an important cause of severe neurological deficits including delayed mental and motor development, epilepsy, major cognitive deficits and blindness. The interaction between neurons, astrocytes and endothelial cells plays a central role coupling energy supply with changes in neuronal activity. Traditionally, experimental research focused on neurons, whereas astrocytes have been more related to the damage mechanisms of PA. Astrocytes carry out a number of functions that are critical to normal nervous system function, including uptake of neurotransmitters, regulation of pH and ion concentrations, and metabolic support for neurons. In this work, we aim to review metabolic neuron-astrocyte interactions with the purpose of encourage further research in this area in the context of PA, which is highly complex and its mechanisms and pathways have not been fully elucidated to this day. PMID:27445788

  8. Changes of microstructure characteristics and intermolecular interactions of preserved egg white gel during pickling.

    PubMed

    Zhao, Yan; Chen, Zhangyi; Li, Jianke; Xu, Mingsheng; Shao, Yaoyao; Tu, Yonggang

    2016-07-15

    Changes in gel microstructure characteristics and in intermolecular interactions of preserved egg whites during pickling were investigated. Spin-spin relaxation times of preserved egg whites significantly decreased in the first 8 days and remained unchanged after the 16th day. SEM images revealed a three-dimensional gel network, interwoven with a loose linear fibrous mesh structure. The protein gel mesh structure became more regular, smaller, and compacted with pickling time. Free sulfhydryl contents in the egg whites increased significantly, while total sulfhydryl contents dramatically decreased during pickling. The primary intermolecular forces in the preserved egg white gels were ionic and disulfide bonds. Secondary forces included hydrophobic interaction and relatively few hydrogen bonds. During the first 8 days, the proportion of ionic bonds sharply decreased, and that of disulfide bonds increased over the first 24 days. PMID:26948621

  9. Aerosols, Clouds, and Precipitation as Scale Interactions in the Climate System and Controls on Climate Change

    NASA Astrophysics Data System (ADS)

    Donner, Leo

    Clouds are major regulators of atmospheric energy flows. Their character depends on atmospheric composition, dynamics, and thermodynamic state. Clouds can assume organized structures whose scales are planetary, while processes important for determining basic properties occur on the scale of microns. The range of processes, scales, and interactions among them has precluded the development of concise theories for the role of clouds in climate, and limitations in modeling clouds in complex climate models remain among the key uncertainties in understanding and projecting climate change. The distribution function of vertical velocities (updraft speeds) in clouds is an important control on climate forcing by clouds and possibly a strong correlate with climate sensitivity. (Climate forcing refers to the change in Earth's energy balance as atmospheric composition changes, in particular, due to human activity. Climate sensitivity is defined here as the equilibrium change in globally averaged annual surface temperature as a result of doubled carbon dioxide.) Vertical velocities are central because they determine the thermodynamic environment governing phase changes of water, with both equilibrium and non-equilibrium phenomena important. The spatial and temporal spectra of relevant vertical velocities includes scales both numerically resolved by climate models and below their resolution limit. The latter implies a requirement to parameterize these smaller scale motions in models. The scale dependence of vertical velocities and emerging observational constraints on their distribution provide new opportunities for representing aerosols, clouds, and precipitation in climate models. Success in doing so could provide important breakthroughs in understanding both climate forcing and sensitivity.

  10. Interactive change detection based on dissimilarity image and decision tree classification

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Crouzil, Alain; Puel, Jean-Baptiste

    2015-02-01

    Our study mainly focus on detecting changed regions in two images of the same scene taken by digital cameras at different times. The images taken by digital cameras generally provide less information than multi-channel remote sensing images. Moreover, the application-dependent insignificant changes, such as shadows or clouds, may cause the failure of the classical methods based on image differences. The machine learning approach seems to be promising, but the lack of a sufficient volume of training data for photographic landscape observatories discards a lot of methods. So we investigate in this work the interactive learning approach and provide a discriminative model that is a 16-dimensional feature space comprising the textural appearance and contextual information. Dissimilarity measures in different neighborhood sizes are used to detect the difference within the neighborhood of an image pair. To detect changes between two images, the user designates change and non-change samples (pixel sets) in the images using a selection tool. This data is used to train a classifier using decision tree training method which is then applied to all the other pixels of the image pair. The experiments have proved the potential of the proposed approach.

  11. Carbon and water interactions and the footprint of climate-change activities (Invited)

    NASA Astrophysics Data System (ADS)

    Jackson, R. B.

    2010-12-01

    Although climate change will have profound effects on ecosystems worldwide, climate policies will alter many terrestrial systems more in the coming decade than climate change will. Biofuels, renewable portfolio standards for electricity, and carbon pricing and offsets all change the global carbon cycle by design, competing for land area and land uses in ways that alter native systems. Just as importantly, such activities inevitably - and profoundly - change the Earth’s water cycle. In cases such as reduced emissions from deforestation and degradation (REDD), climate change activities could cut global deforestation rates in half by 2030, preserving 1.5 to 3 billion 9 metric tons of CO2-equivalent (tCO2e) emissions yearly and preserving the benefits of tropical forests for water recycling. In other cases, such as afforestation (tree planting) or biofuels, fundamental trade-offs exist between maximizing net primary production on land and the amounts of water required for such activities. Fundamental biogeochemical knowledge of carbon-water interactions can help to maximize the benefits of climate policies while preserving water resources and other ecosystem services wherever possible.

  12. Investigation of Protein-Protein Interactions and Conformational Changes in Hedgehog Signaling Pathway by FRET.

    PubMed

    Fu, Lin; Lv, Xiangdong; Xiong, Yue; Zhao, Yun

    2015-01-01

    Protein-protein interactions and signal-induced protein conformational changes are fundamental molecular events that are considered as essential in modern life sciences. Among various techniques developed to study such phenomena, fluorescence resonance energy transfer (FRET) is a widely used method with many advantages in detecting these molecular events. Here, we describe the application of FRET in the mechanistic investigation of cell signal transduction, taking the example of the Hh signaling pathway, which plays a critical role in embryonic development and tissue homeostasis. A number of general guidelines as well as some key notes have been summarized as a protocol for reader's reference. PMID:26179039

  13. `Our Changing Climate' - A new interactive game about weather, climate, the Earth's energy budget and the impacts caused by climate change

    NASA Astrophysics Data System (ADS)

    Colon-Robles, M.; Lorentz, K.; Ruhlman, K.; Gilman, I.; Chambers, L. H.

    2010-12-01

    ‘Our Changing Climate’ is a brand new game developed at NASA’s Langley Research Center by the Informal Education group and the Science Directorate to educate the public on Earth’s climate system how the Sun, ocean, atmosphere, clouds, ice, land, and life interact with each other, and how these interactions are changing due to anthropogenic effects. The game was designed for students in middle school (5th and 8th grade) between the ages of 10-14 as part of the NASA's Summer of Innovation campaign for excellence in science, technology, engineering and mathematics, or STEM, education. The game, ‘Our Changing Climate’, is composed of a series of interactive boards, featuring the following topics: (1) the difference between weather and climate - “Weather vs Climate”, (2) the interactions of clouds and greenhouse gases on short and long wave radiation - “Greenhouse Gases and Clouds”, and (3) the definition of albedo and the importance of bright surfaces over the Arctic - “Arctic Temperature”. Each interactive board presents a climate system and steps the student or spectator through the climate interaction using “clues” and hands-on items that they need to put correctly on the board to understand the concept. Once the student or spectator finishes this part, they then have a better grasp of the concept and are able to understand how these interactions are changing due to the increase in average global temperature. This knowledge is then tested or “driven home” with interactive questions that show how these interactions in our climate are changing today. The concept is then reinforced with an example of a recent event presented in the media. The game has been piloted in outreach and informal settings, as well as for professional development of educators. The game, interactions and engagement of each of the audiences mentioned will be presented.

  14. Effects of solar ultraviolet radiation on terrestrial ecosystems. Patterns, mechanisms, and interactions with climate change.

    PubMed

    Ballaré, C L; Caldwell, M M; Flint, S D; Robinson, S A; Bornman, J F

    2011-02-01

    Ultraviolet radiation (UV) is a minor fraction of the solar spectrum reaching the ground surface. In this assessment we summarize the results of previous work on the effects of the UV-B component (280-315 nm) on terrestrial ecosystems, and draw attention to important knowledge gaps in our understanding of the interactive effects of UV radiation and climate change. We highlight the following points: (i) The effects of UV-B on the growth of terrestrial plants are relatively small and, because the Montreal Protocol has been successful in limiting ozone depletion, the reduction in plant growth caused by increased UV-B radiation in areas affected by ozone decline since 1980 is unlikely to have exceeded 6%. (ii) Solar UV-B radiation has large direct and indirect (plant-mediated) effects on canopy arthropods and microorganisms. Therefore, trophic interactions (herbivory, decomposition) in terrestrial ecosystems appear to be sensitive to variations in UV-B irradiance. (iii) Future variations in UV radiation resulting from changes in climate and land-use may have more important consequences on terrestrial ecosystems than the changes in UV caused by ozone depletion. This is because the resulting changes in UV radiation may affect a greater range of ecosystems, and will not be restricted solely to the UV-B component. (iv) Several ecosystem processes that are not particularly sensitive to UV-B radiation can be strongly affected by UV-A (315-400 nm) radiation. One example is the physical degradation of plant litter. Increased photodegradation (in response to reduced cloudiness or canopy cover) will lead to increased carbon release to the atmosphere via direct and indirect mechanisms. PMID:21253661

  15. Climate Warming and Seasonal Precipitation Change Interact to Limit Species Distribution Shifts across Western North America

    PubMed Central

    Harsch, Melanie A.; HilleRisLambers, Janneke

    2016-01-01

    Using an extensive network of occurrence records for 293 plant species collected over the past 40 years across a climatically diverse geographic section of western North America, we find that plant species distributions were just as likely to shift upwards (i.e., towards higher elevations) as downward (i.e., towards lower elevations)–despite consistent warming across the study area. Although there was no clear directional response to climate warming across the entire study area, there was significant region- to region- variation in responses (i.e. from as many as 73% to as few as 32% of species shifting upward). To understand the factors that might be controlling region-specific distributional shifts of plant species, we explored the relationship between the direction of change in distribution limits and the nature of recent climate change. We found that the direction that distribution limits shifted was explained by an interaction between the rate of change in local summer temperatures and seasonal precipitation. Specifically, species were more likely to shift upward at their upper elevational limit when minimum temperatures increased and snowfall was unchanging or declined at slower rates (<0.5 mm/year). This suggests that both low temperature and water availability limit upward shifts at upper elevation limits. By contrast, species were more likely to shift upwards at their lower elevation limit when maximum temperatures increased, but also shifted upwards under conditions of cooling temperatures when precipitation decreased. This suggests increased water stress may drive upward shifts at lower elevation limits. Our results suggest that species’ elevational distribution shifts are not predictable by climate warming alone but depend on the interaction between seasonal temperature and precipitation change. PMID:27447834

  16. Analysing change in music therapy interactions of children with communication difficulties.

    PubMed

    Spiro, Neta; Himberg, Tommi

    2016-05-01

    Music therapy has been found to improve communicative behaviours and joint attention in children with autism, but it is unclear what in the music therapy sessions drives those changes. We developed an annotation protocol and tools to accumulate large datasets of music therapy, for analysis of interaction dynamics. Analysis of video recordings of improvisational music therapy sessions focused on simple, unambiguous individual and shared behaviours: movement and facing behaviours, rhythmic activity and musical structures and the relationships between them. To test the feasibility of the protocol, early and late sessions of five client-therapist pairs were annotated and analysed to track changes in behaviours. To assess the reliability and validity of the protocol, inter-rater reliability of the annotation tiers was calculated, and the therapists provided feedback about the relevance of the analyses and results. This small-scale study suggests that there are both similarities and differences in the profiles of client-therapist sessions. For example, all therapists faced the clients most of the time, while the clients did not face back so often. Conversely, only two pairs had an increase in regular pulse from early to late sessions. More broadly, similarity across pairs at a general level is complemented by variation in the details. This perhaps goes some way to reconciling client- and context-specificity on one hand and generalizability on the other. Behavioural characteristics seem to influence each other. For instance, shared rhythmic pulse alternated with mutual facing and the occurrence of shared pulse was found to relate to the musical structure. These observations point towards a framework for looking at change in music therapy that focuses on networks of variables or broader categories. The results suggest that even when starting with simple behaviours, we can trace aspects of interaction and change in music therapy, which are seen as relevant by therapists

  17. Analysing change in music therapy interactions of children with communication difficulties

    PubMed Central

    2016-01-01

    Music therapy has been found to improve communicative behaviours and joint attention in children with autism, but it is unclear what in the music therapy sessions drives those changes. We developed an annotation protocol and tools to accumulate large datasets of music therapy, for analysis of interaction dynamics. Analysis of video recordings of improvisational music therapy sessions focused on simple, unambiguous individual and shared behaviours: movement and facing behaviours, rhythmic activity and musical structures and the relationships between them. To test the feasibility of the protocol, early and late sessions of five client–therapist pairs were annotated and analysed to track changes in behaviours. To assess the reliability and validity of the protocol, inter-rater reliability of the annotation tiers was calculated, and the therapists provided feedback about the relevance of the analyses and results. This small-scale study suggests that there are both similarities and differences in the profiles of client–therapist sessions. For example, all therapists faced the clients most of the time, while the clients did not face back so often. Conversely, only two pairs had an increase in regular pulse from early to late sessions. More broadly, similarity across pairs at a general level is complemented by variation in the details. This perhaps goes some way to reconciling client- and context-specificity on one hand and generalizability on the other. Behavioural characteristics seem to influence each other. For instance, shared rhythmic pulse alternated with mutual facing and the occurrence of shared pulse was found to relate to the musical structure. These observations point towards a framework for looking at change in music therapy that focuses on networks of variables or broader categories. The results suggest that even when starting with simple behaviours, we can trace aspects of interaction and change in music therapy, which are seen as relevant by therapists

  18. Top-down Control of Stream Food Webs: Indirect Effects by Changed Behaviour and Species Interactions

    NASA Astrophysics Data System (ADS)

    Winkelmann, C.; Petzoldt, T.; Koop, J. H.; Benndorf, J.

    2005-05-01

    Predators may directly control stream food webs by consuming invertebrates. But sub lethal effects on prey such as change of activity rhythm or feeding behaviour may lead to indirect effects of predation on other species. Thus, predators may strongly effect invertebrate community structure. The aim of a currently running paired ecosystem experiment is to detect changes of species interaction induced by benthivorous gudgeon (Gobio gobio). For this purpose we link the measurement of physiological fitness parameters to the observation of behavioural changes. Preliminary studies indicated a top-down control of the drift activity of Baetis larvae, while a bottom-up effect could not be observed. The presence of benthivorous gudgeon led to a significantly changed species composition of the invertebrate drift and reduced drift activity of Baetis larvae compared to the fish free control. The diurnal drift pattern of Baetis larvae with a nocturnal peak was observed both in the control and fish reaches. Thus benthivorous gudgeon controls the drift behaviour in a similar way as known for drift-feeding trout. The content of triglycerides and glycogen did not differ between the drifting and not-drifting individuals. Therefore their energetic status does not seem to control drift the activity of Baetis larvae.

  19. Modeling Abrupt Change in Global Sea Level Arising from Ocean - Ice-Sheet Interaction

    SciTech Connect

    Holland, David M

    2011-09-24

    It is proposed to develop, validate, and apply a coupled ocean ice-sheet model to simulate possible, abrupt future change in global sea level. This research is to be carried out collaboratively between an academic institute and a Department of Energy Laboratory (DOE), namely, the PI and a graduate student at New York University (NYU) and climate model researchers at the Los Alamos National Laboratory (LANL). The NYU contribution is mainly in the area of incorporating new physical processes into the model, while the LANL efforts are focused on improved numerics and overall model development. NYU and LANL will work together on applying the model to a variety of modeling scenarios of recent past and possible near-future abrupt change to the configuration of the periphery of the major ice sheets. The project's ultimate goal is to provide a robust, accurate prediction of future global sea level change, a feat that no fully-coupled climate model is currently capable of producing. This proposal seeks to advance that ultimate goal by developing, validating, and applying a regional model that can simulate the detailed processes involved in sea-level change due to ocean ice-sheet interaction. Directly modeling ocean ice-sheet processes in a fully-coupled global climate model is not a feasible activity at present given the near-complete absence of development of any such causal mechanism in these models to date.

  20. Interaction of Insect Defoliation, Wildfires and Climate Change on Carbon Dynamics

    NASA Astrophysics Data System (ADS)

    Hom, J.; van Tuyl, S.; Scheller, R.; Pan, Y.; Clark, K.; Cole, J.; Foster, J.; Patterson, M.; Gallagher, M.

    2009-05-01

    We assess and predict the interactive effects of gypsy moth defoliation, fire management, and climate change on carbon uptake, forest productivity, species composition, and tree mortality in the New Jersey Pine Barrens. This effort will combine carbon flux measurements, a forest landscape disturbance model, and field monitoring data. We will determine how interactions among these disturbances affect current management and potential carbon management goals. The LANDIS-II forest landscape simulation model in this study uses three model extensions or modules: the Dynamic Fire System (DFS) extension, the Biomass Succession extension, and an insect defoliation extension. Parameterization of the DFS and the Biomass Succession extension uses new and existing data sources for the study area. This includes flux tower data from three upland forest types, for annual net ecosystem exchange of carbon taken before and after defoliation as well as during prescribed burns. An intensified grid of FIA-type plots around each tower (up to 24 plots per tower) provides additional biometric information. The study conducted a field mortality survey and canopy foliar analysis to understand the process of forest decline with insect defoliation. This project provides a predictive framework for working through landscape to regional management scenarios in areas with multiple, interacting management priorities that can be applied across the US, especially in areas where both insect and fire disturbances occur.

  1. The influence of phase changes on debris-cloud interactions with protected structures

    SciTech Connect

    Lawrence, R.J.; Kmetyk, L.N.; Chhabildas, L.C.

    1994-05-16

    The physical state of the debris cloud generated by the interaction of a projectile with a thin target depends on the energy balance associated with above the sound speeds of the impact event. At impact velocities well materials involved, the cloud is expected to be primarily molten, but with some vapor present. A series of numerical calculations using the multi-dimensional finite-difference hydrocode CTH has been used to evaluate the effect of phase changes (i.e., different vapor fractions) on these clouds, and their subsequent interaction with backwall structures. In the calculations, higher concentrations of vapor are achieved by increasing the initial temperature of both the projectile and the thin shield while keeping the impact velocity constant, and by actually increasing the impact velocity. The nature of the debris cloud and its subsequent loading on the protected structure depend on both its thermal and physical state. This interaction can cause rupture, spallation or simply bulging of the backwall. These computational results are discussed and compared with new experimental observations obtained at an impact velocity of {approximately}10 km/s. In the experiment, the debris cloud was generated by the impact of a plate-shaped titanium projectile with a thin titanium shield.

  2. The Influence of Seasonally Changing Groundwater/Surface Water Interaction on the Composition of Sediment Fauna

    NASA Astrophysics Data System (ADS)

    Schmidt, S. I.; Hahn, H. J.; Hatton, T. J.; Woodbury, R. J.; Watson, G. D.

    2005-05-01

    Sediment fauna in both streams and groundwater are crucial to the functioning of sediment processes, and are known to be highly influenced by hydraulics. But how does the seasonal variation of groundwater/surface water interactions influence the faunal composition? This question was addressed in a small Western Australian catchment, where four stream sediment sites and 30 groundwater bores were sampled over the period of one year. Mixed fauna at those sites displaying groundwater/surface water interaction was expected. However, there were virtually no species common to groundwater bores and stream sediment tubes, although they were sampled using the same method. The missing species exchange was probably due to the small pore spaces. Since the hydrological and chemical variety within groundwater sites was surprising, going far beyond gradually changing interactions with surface water, we grouped the groundwater sites into four major hydrogeological classes and looked for patterns with which fauna reflected these groups. In two of these hydrogeological groups (Artesian and concentration zones) no fauna was found at all, while fauna was sampled regularly in discharging and recharging zones. Fauna in groundwater bores also reflected whether groundwater was recharged from precipitation alone or also at least seasonally from the stream.

  3. In vitro cytokines profile and ultrastructural changes of microglia and macrophages following interaction with Leishmania.

    PubMed

    Ramos, Patricia Karla Santos; Brito, Maysa de Vasconcelos; Silveira, Fernando Tobias; Salgado, Cláudio Guedes; De Souza, Wanderley; Picanço-Diniz, Cristovam Wanderley; Picanço-Diniz, José Antonio Junior

    2014-07-01

    In the present study, we assessed morphological changes and cytokine production after in vitro interaction with causative agents of American cutaneous leishmaniasis and compared the microglia and macrophage immune responses. Cultures of microglia and macrophages infected with stationary-phase promastigotes of Leishmania (Viannia) shawi, Leishmania (Viannia) braziliensis or Leishmania (Leishmania) amazonensis were evaluated 24, 48 and 72 h after interaction. Macrophages only presented the classical phagocytic process while microglia also displayed large cytoplasmic projections similar to the ruffles described in macropinocytosis. In the macrophage cultures, the percentage of infected cells increased over time, in a fashion that was dependent on the parasite species. In contrast, in microglial cells as the culture time progressed, there was a significant reduction in the percentage of infected cells independent of parasite species. Measurements of cytokines in macrophage cultures 48 h after interactions revealed distinct expression patterns for different parasites, whereas in microglial cultures they were similar for all Leishmania tested species. Taken together, our results suggest that microglia may have a higher phagocytic ability and cytotoxic potential than macrophages for all investigated species. The robust response of microglia against all parasite species may suggest microglia have an important role in the defence against cerebral leishmaniasis. PMID:24717447

  4. Substrate-induced changes in domain interaction of vacuolar H⁺-pyrophosphatase.

    PubMed

    Hsu, Shen-Hsing; Lo, Yueh-Yu; Liu, Tseng-Huang; Pan, Yih-Jiuan; Huang, Yun-Tzu; Sun, Yuh-Ju; Hung, Cheng-Chieh; Tseng, Fan-Gang; Yang, Chih-Wei; Pan, Rong-Long

    2015-01-01

    Single molecule atomic force microscopy (smAFM) was employed to unfold transmembrane domain interactions of a unique vacuolar H(+)-pyrophosphatase (EC 3.6.1.1) from Vigna radiata. H(+)-Pyrophosphatase is a membrane-embedded homodimeric protein containing a single type of polypeptide and links PPi hydrolysis to proton translocation. Each subunit consists of 16 transmembrane domains with both ends facing the lumen side. In this investigation, H(+)-pyrophosphatase was reconstituted into the lipid bilayer in the same orientation for efficient fishing out of the membrane by smAFM. The reconstituted H(+)-pyrophosphatase in the lipid bilayer showed an authentically dimeric structure, and the size of each monomer was ∼4 nm in length, ∼2 nm in width, and ∼1 nm in protrusion height. Upon extracting the H(+)-pyrophosphatase out of the membrane, force-distance curves containing 10 peaks were obtained and assigned to distinct domains. In the presence of pyrophosphate, phosphate, and imidodiphosphate, the numbers of interaction curves were altered to 7, 8, and 10, respectively, concomitantly with significant modification in force strength. The substrate-binding residues were further replaced to verify these domain changes upon substrate binding. A working model is accordingly proposed to show the interactions between transmembrane domains of H(+)-pyrophosphatase in the presence and absence of substrate and its analog. PMID:25451931

  5. Cation Interactions and Membrane Potential Induce Conformational Changes in NaPi-IIb.

    PubMed

    Patti, Monica; Fenollar-Ferrer, Cristina; Werner, Andreas; Forrest, Lucy R; Forster, Ian C

    2016-09-01

    Voltage-dependence of Na(+)-coupled phosphate cotransporters of the SLC34 family arises from displacement of charges intrinsic to the protein and the binding/release of one Na(+) ion in response to changes in the transmembrane electric field. Candidate coordination residues for the cation at the Na1 site were previously predicted by structural modeling using the x-ray structure of dicarboxylate transporter VcINDY as template and confirmed by functional studies. Mutations at Na1 resulted in altered steady-state and presteady-state characteristics that should be mirrored in the conformational changes induced by membrane potential changes. To test this hypothesis by functional analysis, double mutants of the flounder SLC34A2 protein were constructed that contain one of the Na1-site perturbing mutations together with a substituted cysteine for fluorophore labeling, as expressed in Xenopus oocytes. The locations of the mutations were mapped onto a homology model of the flounder protein. The effects of the mutagenesis were characterized by steady-state, presteady-state, and fluorometric assays. Changes in fluorescence intensity (ΔF) in response to membrane potential steps were resolved at three previously identified positions. These fluorescence data corroborated the altered presteady-state kinetics upon perturbation of Na1, and furthermore indicated concomitant changes in the microenvironment of the respective fluorophores, as evidenced by changes in the voltage dependence and time course of ΔF. Moreover, iodide quenching experiments indicated that the aqueous nature of the fluorophore microenvironment depended on the membrane potential. These findings provide compelling evidence that membrane potential and cation interactions induce significant large-scale structural rearrangements of the protein. PMID:27602725

  6. Interaction effects of climate and land use/land cover change on soil organic carbon sequestration.

    PubMed

    Xiong, Xiong; Grunwald, Sabine; Myers, D Brenton; Ross, C Wade; Harris, Willie G; Comerford, Nicolas B

    2014-09-15

    Historically, Florida soils stored the largest amount of soil organic carbon (SOC) among the conterminous U.S. states (2.26 Pg). This region experienced rapid land use/land cover (LULC) shifts and climate change in the past decades. The effects of these changes on SOC sequestration are unknown. The objectives of this study were to 1) investigate the change in SOC stocks in Florida to determine if soils have acted as a net sink or net source for carbon (C) over the past four decades and 2) identify the concomitant effects of LULC, LULC change, and climate on the SOC change. A total of 1080 sites were sampled in the topsoil (0-20 cm) between 2008 and 2009 representing the current SOC stocks, 194 of which were selected to collocate with historical sites (n = 1251) from the Florida Soil Characterization Database (1965-1996) for direct comparison. Results show that SOC stocks significantly differed among LULC classes--sugarcane and wetland contained the highest SOC, followed by improved pasture, urban, mesic upland forest, rangeland, and pineland while crop, citrus and xeric upland forest remained the lowest. The surface 20 cm soils acted as a net sink for C with the median SOC significantly increasing from 2.69 to 3.40 kg m(-2) over the past decades. The SOC sequestration rate was LULC dependent and controlled by climate factors interacting with LULC. Higher temperature tended to accelerate SOC accumulation, while higher precipitation reduced the SOC sequestration rate. Land use/land cover change observed over the past four decades also favored the C sequestration in soils due to the increase in the C-rich wetland area by ~140% and decrease in the C-poor agricultural area by ~20%. Soils are likely to provide a substantial soil C sink considering the climate and LULC projections for this region. PMID:25010945

  7. COMBINED AND INTERACTIVE EFFECTS OF GLOBAL CLIMATE CHANGE AND TOXICANTS ON POPULATIONS AND COMMUNITIES

    PubMed Central

    Moe, S Jannicke; De Schamphelaere, Karel; Clements, William H; Sorensen, Mary T; Van den Brink, Paul J; Liess, Matthias

    2013-01-01

    Increased temperature and other environmental effects of global climate change (GCC) have documented impacts on many species (e.g., polar bears, amphibians, coral reefs) as well as on ecosystem processes and species interactions (e.g., the timing of predator–prey interactions). A challenge for ecotoxicologists is to predict how joint effects of climatic stress and toxicants measured at the individual level (e.g., reduced survival and reproduction) will be manifested at the population level (e.g., population growth rate, extinction risk) and community level (e.g., species richness, food-web structure). The authors discuss how population- and community-level responses to toxicants under GCC are likely to be influenced by various ecological mechanisms. Stress due to GCC may reduce the potential for resistance to and recovery from toxicant exposure. Long-term toxicant exposure can result in acquired tolerance to this stressor at the population or community level, but an associated cost of tolerance may be the reduced potential for tolerance to subsequent climatic stress (or vice versa). Moreover, GCC can induce large-scale shifts in community composition, which may affect the vulnerability of communities to other stressors. Ecological modeling based on species traits (representing life-history traits, population vulnerability, sensitivity to toxicants, and sensitivity to climate change) can be a promising approach for predicting combined impacts of GCC and toxicants on populations and communities. Environ. Toxicol. Chem. 2013;32:49–61. © 2012 SETAC PMID:23147390

  8. Tree mortality from drought, insects, and their interactions in a changing climate.

    PubMed

    Anderegg, William R L; Hicke, Jeffrey A; Fisher, Rosie A; Allen, Craig D; Aukema, Juliann; Bentz, Barbara; Hood, Sharon; Lichstein, Jeremy W; Macalady, Alison K; McDowell, Nate; Pan, Yude; Raffa, Kenneth; Sala, Anna; Shaw, John D; Stephenson, Nathan L; Tague, Christina; Zeppel, Melanie

    2015-11-01

    Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects - bark beetles and defoliators - which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree-insect interactions will better inform projections of forest ecosystem responses to climate change. PMID:26058406

  9. Assessing the Land-Ocean Interaction under Extreme Climate Change Condition - a Modeling Approach

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Wang, T.; Leung, R.; Balaguru, K.; Hibbard, K. A.

    2011-12-01

    Many modeling applications, at global and regional scales, have demonstrated that numerical models are useful tools to quantify the uncertainty and the interactions between natural physical and biogeochemical processes and human activities in coastal regions. A regional integrated assessment modeling framework to investigate the interactions of agriculture and land use, coastal ecological issues, energy supply and effects of climate changes is under development by Pacific Northwest National Laboratory (PNNL), with specific application to the Gulf of Mexico. The Gulf is vulnerable to the direct impacts of climate changes, such as sea level rise, hurricane-induced storm surge and extreme floods due to high precipitation and river run-off. This presentation will focus on the coastal modeling aspect of this integrated modeling approach. An unstructured-grid finite volume coastal ocean model, which has the capability of simulating coastal circulation, wave and storm surges, sediment transport and biogeochemical processes, is applied to simulate hurricane storm surges and extreme flood events in the coastal region of Gulf of Mexico. Specifically, storm surge along the US Southeast coasts and freshwater plume in the Mississippi Delta were simulated and compared to observations. Numerical sensitivity studies with boundary conditions and forcing indicated the urgent need of a real observation network as well as the importance of accurate model predictions at regional scales to drive the model at smaller scales. The implication of natural pressures, such as storm surge and flooding to biogeochemical processes and marine ecosystem will be discussed.

  10. Tree mortality from drought, insects, and their interactions in a changing climate

    USGS Publications Warehouse

    Anderegg, William R. L.; Hicke, Jeffrey A.; Fisher, Rosie A.; Allen, Craig D.; Aukema, Juliann E.; Bentz, Barbara; Hood, Sharon; Lichstein, Jeremy W.; Macalady, Alison K.; McDowell, Nate G.; Pan, Yude; Raffa, Kenneth; Sala, Anna; Shaw, John D.; Stephenson, Nathan L.; Tague, Christina L.; Zeppel, Melanie

    2015-01-01

    Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects – bark beetles and defoliators – which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree–insect interactions will better inform projections of forest ecosystem responses to climate change.

  11. The smell of change: warming affects species interactions mediated by chemical information.

    PubMed

    Sentis, Arnaud; Ramon-Portugal, Felipe; Brodeur, Jacques; Hemptinne, Jean-Louis

    2015-10-01

    Knowledge of how temperature influences an organism's physiology and behaviour is of paramount importance for understanding and predicting the impacts of climate change on species' interactions. While the behaviour of many organisms is driven by chemical information on which they rely on to detect resources, conspecifics, natural enemies and competitors, the effects of temperature on infochemical-mediated interactions remain largely unexplored. Here, we experimentally show that temperature strongly influences the emission of infochemicals by ladybeetle larvae, which, in turn, modifies the oviposition behaviour of conspecific females. Temperature also directly affects female perception of infochemicals and their oviposition behaviour. Our results suggest that temperature-mediated effects on chemical communication can influence flows across system boundaries (e.g. immigration and emigration) and thus alter the dynamics and stability of ecological networks. We therefore argue that investigating the effects of temperature on chemical communication is a crucial step towards a better understanding of the functioning of ecological communities facing rapid environmental changes. PMID:25820469

  12. Flow regime, temperature, and biotic interactions drive differential declines of trout species under climate change

    USGS Publications Warehouse

    Wenger, S.J.; Isaak, D.J.; Luce, C.H.; Neville, H.M.; Fausch, K.D.; Dunham, J.B.; Dauwalter, D.C.; Young, M.K.; Elsner, M.M.; Rieman, B.E.; Hamlet, A.F.; Williams, J.E.

    2011-01-01

    Broad-scale studies of climate change effects on freshwater species have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We use downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows and increased temperatures on four interacting species of trout across the interior western United States (1.01 million km2), based on empirical statistical models built from fish surveys at 9,890 sites. Projections under the 2080s A1B emissions scenario forecast a mean 47% decline in total suitable habitat for all trout, a group of fishes of major socioeconomic and ecological significance. We project that native cutthroat trout Oncorhynchus clarkii, already excluded from much of its potential range by nonnative species, will lose a further 58% of habitat due to an increase in temperatures beyond the species' physiological optima and continued negative biotic interactions. Habitat for nonnative brook trout Salvelinus fontinalis and brown trout Salmo trutta is predicted to decline by 77% and 48%, respectively, driven by increases in temperature and winter flood frequency caused by warmer, rainier winters. Habitat for rainbow trout, Oncorhynchus mykiss, is projected to decline the least (35%) because negative temperature effects are partly offset by flow regime shifts that benefit the species. These results illustrate how drivers other than temperature influence species response to climate change. Despite some uncertainty, large declines in trout habitat are likely, but our findings point to opportunities for strategic targeting of mitigation efforts to appropriate stressors and locations.

  13. Flow regime, temperature, and biotic interactions drive differential declines of trout species under climate change

    PubMed Central

    Wenger, Seth J.; Isaak, Daniel J.; Luce, Charles H.; Neville, Helen M.; Fausch, Kurt D.; Dunham, Jason B.; Dauwalter, Daniel C.; Young, Michael K.; Elsner, Marketa M.; Rieman, Bruce E.; Hamlet, Alan F.; Williams, Jack E.

    2011-01-01

    Broad-scale studies of climate change effects on freshwater species have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We use downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows and increased temperatures on four interacting species of trout across the interior western United States (1.01 million km2), based on empirical statistical models built from fish surveys at 9,890 sites. Projections under the 2080s A1B emissions scenario forecast a mean 47% decline in total suitable habitat for all trout, a group of fishes of major socioeconomic and ecological significance. We project that native cutthroat trout Oncorhynchus clarkii, already excluded from much of its potential range by nonnative species, will lose a further 58% of habitat due to an increase in temperatures beyond the species’ physiological optima and continued negative biotic interactions. Habitat for nonnative brook trout Salvelinus fontinalis and brown trout Salmo trutta is predicted to decline by 77% and 48%, respectively, driven by increases in temperature and winter flood frequency caused by warmer, rainier winters. Habitat for rainbow trout, Oncorhynchus mykiss, is projected to decline the least (35%) because negative temperature effects are partly offset by flow regime shifts that benefit the species. These results illustrate how drivers other than temperature influence species response to climate change. Despite some uncertainty, large declines in trout habitat are likely, but our findings point to opportunities for strategic targeting of mitigation efforts to appropriate stressors and locations. PMID:21844354

  14. Arctic Sea Ice Changes, Interactions, and Feedbacks on the Arctic Climate during the Satellite Era

    NASA Astrophysics Data System (ADS)

    Wang, X.; Key, J. R.; Liu, Y.

    2011-12-01

    the shortcomings of current climate models in the projections of future climate change and feedback mechanisms at high latitudes. Interactions and feedbacks between clouds, sea ice, and various atmospheric circulation patterns in the Arctic are also investigated based on multi-decadal satellite products, including cloud characteristics and radiation fluxes from the MODerate resolution Imaging Spectroradiometer (MODIS) data and the APP-x dataset, sea ice products from Special Sensor Microwave/Imager (SSM/I), and various atmospheric parameters from reanalysis data sets. Results demonstrate that changes in sea ice concentration and cloud cover played major roles in the magnitude of recent Arctic surface temperature trends. Interactions between sea ice and clouds are strong, such that recent shrinking of sea ice extent might influence future cloud cover changes. Not surprisingly, cloud cover is also affected by changes in large-scale atmospheric circulation patterns. Quantitative analyses of the relationships between trends in these parameters provide new insight into polar climates.

  15. Nectin-Like Interactions between Poliovirus and Its Receptor Trigger Conformational Changes Associated with Cell Entry

    PubMed Central

    Strauss, Mike; Filman, David J.; Belnap, David M.; Cheng, Naiqian; Noel, Roane T.

    2015-01-01

    ABSTRACT Poliovirus infection is initiated by attachment to a receptor on the cell surface called Pvr or CD155. At physiological temperatures, the receptor catalyzes an irreversible expansion of the virus to form an expanded form of the capsid called the 135S particle. This expansion results in the externalization of the myristoylated capsid protein VP4 and the N-terminal extension of the capsid protein VP1, both of which become inserted into the cell membrane. Structures of the expanded forms of poliovirus and of several related viruses have recently been reported. However, until now, it has been unclear how receptor binding triggers viral expansion at physiological temperature. Here, we report poliovirus in complex with an enzymatically partially deglycosylated form of the 3-domain ectodomain of Pvr at a 4-Å resolution, as determined by cryo-electron microscopy. The interaction of the receptor with the virus in this structure is reminiscent of the interactions of Pvr with its natural ligands. At a low temperature, the receptor induces very few changes in the structure of the virus, with the largest changes occurring within the footprint of the receptor, and in a loop of the internal protein VP4. Changes in the vicinity of the receptor include the displacement of a natural lipid ligand (called “pocket factor”), demonstrating that the loss of this ligand, alone, is not sufficient to induce particle expansion. Finally, analogies with naturally occurring ligand binding in the nectin family suggest which specific structural rearrangements in the virus-receptor complex could help to trigger the irreversible expansion of the capsid. IMPORTANCE The cell-surface receptor (Pvr) catalyzes a large structural change in the virus that exposes membrane-binding protein chains. We fitted known atomic models of the virus and Pvr into three-dimensional experimental maps of the receptor-virus complex. The molecular interactions we see between poliovirus and its receptor are

  16. A Web-Based Modelling Platform for Interactive Exploration of Regional Responses to Global Change

    NASA Astrophysics Data System (ADS)

    Holman, I.

    2014-12-01

    Climate change adaptation is a complex human-environmental problem that is framed by the uncertainty in impacts and the adaptation choices available, but is also bounded by real-world constraints such as future resource availability and environmental and institutional capacities. Educating the next generation of informed decision-makers that will be able to make knowledgeable responses to global climate change impacts requires them to have access to information that is credible, accurate, easy to understand, and appropriate. However, available resources are too often produced by inaccessible models for scenario simulations chosen by researchers hindering exploration and enquiry. This paper describes the interactive exploratory web-based CLIMSAVE Integrated Assessment (IA) Platform (www.climsave.eu/iap) that aims to democratise climate change impacts, adaptation and vulnerability modelling. The regional version of the Platform contain linked simulation models (of the urban, agriculture, forestry, water and biodiversity sectors), probabilistic climate scenarios and socio-economic scenarios, that enable users to select their inputs (climate and socioeconomic), rapidly run the models using their input variable settings and view their chosen outputs. The interface of the CLIMSAVE IA Platform is designed to facilitate a two-way iterative process of dialogue and exploration of "what if's" to enable a wide range of users to improve their understanding surrounding impacts, adaptation responses and vulnerability of natural resources and ecosystem services under uncertain futures. This paper will describe the evolution of the Platform and demonstrate how using its holistic framework (multi sector / ecosystem service; cross-sectoral, climate and socio-economic change) will help to assist learning around the challenging concepts of responding to global change.

  17. Multi-finger interaction during involuntary and voluntary single finger force changes

    PubMed Central

    Martin, J.R.; Zatsiorsky, V.M.; Latash, M.L.

    2011-01-01

    Two types of finger interaction are characterized by positive co-variation (enslaving) or negative co-variation (error compensation) of finger forces. Enslaving reflects mechanical and neural connections among fingers, while error compensation results from synergic control of fingers to stabilize their net output. Involuntary and voluntary force changes by a finger were used to explore these patterns. We hypothesized that synergic mechanisms will dominate during involuntary force changes, while enslaving will dominate during voluntary finger force changes. Subjects pressed with all four fingers to match a target force that was 10% of their maximum voluntary contraction (MVC). One of the fingers was unexpectedly raised 5.0 mm at a speed of 30.0 mm/s. During finger raising the subject was instructed “not to intervene voluntarily”. After the finger was passively lifted and a new steady-state achieved, subjects pressed down with the lifted finger, producing a pulse of force voluntarily. The data were analyzed in terms of finger forces and finger modes (hypothetical commands to fingers reflecting their intended involvement). The target finger showed an increase in force during both phases. In the involuntary phase, the target finger force changes ranged between 10.71 ± 1.89% MVC (I-finger) and 16.60 ± 2.26% MVC (L-finger). Generally, non-target fingers displayed a force decrease with a maximum amplitude of −1.49 ± 0.43% MVC (L-finger). Thus, during the involuntary phase, error compensation was observed – non-lifted fingers showed a decrease in force (as well as in mode magnitude). During the voluntary phase, enslaving was observed – non-target fingers showed an increase in force and only minor changes in mode magnitude. The average change in force of non-target fingers ranged from 21.83 ± 4.47% MVC for R-finger (M-finger task) to 0.71 ± 1.10 % MVC for L-finger (I-finger task). The average change in mode of non-target fingers was between −7.34 ± 19

  18. Interaction between Neuroanatomical and Psychological Changes after Mindfulness-Based Training

    PubMed Central

    Santarnecchi, Emiliano; D’Arista, Sicilia; Egiziano, Eutizio; Gardi, Concetta; Petrosino, Roberta; Vatti, Giampaolo; Reda, Mario; Rossi, Alessandro

    2014-01-01

    Several cross-sectional studies have documented neuroanatomical changes in individuals with a long history of meditation, while a few evidences are available about the interaction between neuroanatomical and psychological changes even during brief exposure to meditation. Here we analyzed several morphometric indexes at both cortical and subcortical brain level, as well as multiple psychological dimensions, before and after a brief -8 weeks- Mindfulness Based Stress Reduction (MBSR) training program, in a group of 23 meditation naïve-subjects compared to age-gender matched subjects. We found a significant cortical thickness increase in the right insula and the somatosensory cortex of MBSR trainees, coupled with a significant reduction of several psychological indices related to worry, state anxiety, depression and alexithymia. Most importantly, an interesting correlation between the increase in right insula thickness and the decrease in alexithymia levels during the MBSR training were observed. Moreover, a multivariate pattern classification approach allowed to identify a cluster of regions more responsive to MBSR training across subjects. Taken together, these findings documented the significant impact of a brief MBSR training on brain structures, as well as stressing the idea of MBSR as a valuable tool for alexithymia modulation, also originally providing a plausible neurobiological evidence of a major role of right insula into mediating the observed psychological changes. PMID:25330321

  19. Effects of verbal interaction within cooperative groups on conceptual change in environmental science

    NASA Astrophysics Data System (ADS)

    Lindow, Lynn Eloise

    2000-10-01

    Conceptual change theorists argue that learning occurs as a consequence of students becoming dissatisfied with their initial knowledge and then searching for ideas that are intelligible and plausible. Cooperative groups provide the vehicle for verbal interactions to take place with research indicating improvement in achievement. This study examines the verbal interactions that occur in the cooperative learning setting and how that discourse reflects the components of conceptual change. Cooperative learning groups were videotaped as they participated in active learning sessions in a general science course where the participants experimented with short-term and long-term carbon cycling. Groups were introduced to the guidelines of cooperative learning and group roles were assigned to the groups. Videotaping was followed by stimulated recall interviews with participants from the groups. This data from the videotapes and the stimulated recall interviews were transcribed and assigned categories using the Q. S. R. NUD·IST software program to gain insights into the process of science learning. Interpretations were made based on the findings from the data. Prior knowledge or information gathered by participants in preparation for the active learning session was the starting point for discussions about scientific concepts. Once the discussions began, group members with confidence in their understanding of scientific concepts tended to participate and defend their ideas with examples. The recorder role was the most significant role as the recorder usually directed the discussions in order to develop complete responses. As the discussions continued, explanations by those who were confident assisted other group members with learning scientific concepts---peer teaching. As discourse occurred, conflicts in ideas generated discussion, clarifying ideas, elaborating on ideas, and reformulating science concepts until they were able to reach consensus. Through this process

  20. Interactions in hydrogen of relativistic neon to nickel projectiles: Total charge-changing cross sections

    SciTech Connect

    Chen, C.; Albergo, S.; Caccia, Z.; Costa, S.; Crawford, H.J.; Cronqvist, M.; Engelage, J.; Ferrando, P.; Fonte, R.; Greiner, L.; Guzik, T.G.; Insolia, A.; Jones, F.C.; Knott, C.N.; Lindstrom, P.J.; Mitchell, J.W.; Potenza, R.; Romanski, J.; Russo, G.V.; Soutoul, A.; Testard, O.; Tull, C.E.; Tuve, C.; Waddington, C.J.; Webber, W.R.; Wefel, J.P.; Zhang, X. Space Science Laboratory, University of California, Berkeley, California 94720 Service d'Astrophysique, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette, Cedex Dipartimento di Fisica, Universita di Catania, Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, I 95129-Catania NASA

    1994-06-01

    A liquid hydrogen target was used to study the nuclear fragmentation of beams of relativistic heavy ions, [sup 22]Ne to [sup 58]Ni, over an energy range 400 to 900 MeV/nucleon. The experiments were carried out at the Lawrence Berkeley Laboratory Bevalac HISS facility, using the charge-velocity-rigidity method to identify the charged fragments. Here we describe the general concept of the experiment and present total charge-changing cross sections obtained from 17 separate runs. These new measured cross sections display an energy dependence which follows semiempirical model predictions. The mass dependence of the cross sections behaves as predicted by optical models, but within the experimental energy range, the optical model parameters display a clear energy dependence. The isospin of the projectile nuclei also appears to be an important factor in the interaction process.

  1. Terrestrial ecosystems, increased solar ultraviolet radiation and interactions with other climatic change factors.

    PubMed

    Caldwell, Martyn M; Ballaré, Carlos L; Bornman, Janet F; Flint, Stephan D; Björn, Lars Olof; Teramura, Alan H; Kulandaivelu, G; Tevini, Manfred

    2003-01-01

    Based on research to date, we can state some expectations about terrestrial ecosystem response as several elements of global climate change develop in coming decades. Higher plant species will vary considerably in their response to elevated UV-B radiation, but the most common general effects are reductions in height of plants, decreased shoot mass if ozone reduction is severe, increased quantities of some phenolics in plant tissues and, perhaps, reductions in foliage area. In some cases, the common growth responses may be lessened by increasing CO2 concentrations. However, changes in chemistry of plant tissues will generally not be reversed by elevated CO2. Among other things, changes in plant tissue chemistry induced by enhanced UV-B may reduce consumption of plant tissues by insects and other herbivores, although occasionally consumption may be increased. Pathogen attack on plants may be increased or decreased as a consequence of elevated UV-B, in combination with other climatic changes. This may be affected both by alterations in plant chemistry and direct damage to some pathogens. Water limitation may decrease the sensitivity of some agricultural plants to UV-B, but for vegetation in other habitats, this may not apply. With global warming, the repair of some types of UV damage may be improved, but several other interactions between warming and enhanced UV-B may occur. For example, even though warming may lead to fewer killing frosts, with enhanced UV-B and elevated CO2 levels, some plant species may have increased sensitivity to frost damage. PMID:12659537

  2. Climate change and invasion by intracontinental range-expanding exotic plants: the role of biotic interactions

    PubMed Central

    Morriën, Elly; Engelkes, Tim; Macel, Mirka; Meisner, Annelein; Van der Putten, Wim H.

    2010-01-01

    Background and Aims In this Botanical Briefing we describe how the interactions between plants and their biotic environment can change during range-expansion within a continent and how this may influence plant invasiveness. Scope We address how mechanisms explaining intercontinental plant invasions by exotics (such as release from enemies) may also apply to climate-warming-induced range-expanding exotics within the same continent. We focus on above-ground and below-ground interactions of plants, enemies and symbionts, on plant defences, and on nutrient cycling. Conclusions Range-expansion by plants may result in above-ground and below-ground enemy release. This enemy release can be due to the higher dispersal capacity of plants than of natural enemies. Moreover, lower-latitudinal plants can have higher defence levels than plants from temperate regions, making them better defended against herbivory. In a world that contains fewer enemies, exotic plants will experience less selection pressure to maintain high levels of defensive secondary metabolites. Range-expanders potentially affect ecosystem processes, such as nutrient cycling. These features are quite comparable with what is known of intercontinental invasive exotic plants. However, intracontinental range-expanding plants will have ongoing gene-flow between the newly established populations and the populations in the native range. This is a major difference from intercontinental invasive exotic plants, which become more severely disconnected from their source populations. PMID:20354072

  3. Breadth versus depth: Interactions that stabilize particle assemblies to changes in density or temperature

    NASA Astrophysics Data System (ADS)

    Piñeros, William D.; Baldea, Michael; Truskett, Thomas M.

    2016-02-01

    We use inverse methods of statistical mechanics to explore trade-offs associated with designing interactions to stabilize self-assembled structures against changes in density or temperature. Specifically, we find isotropic, convex-repulsive pair potentials that maximize the density range for which a two-dimensional square lattice is the stable ground state subject to a constraint on the chemical potential advantage it exhibits over competing structures (i.e., "depth" of the associated minimum on the chemical potential hypersurface). We formulate the design problem as a nonlinear program, which we solve numerically. This allows us to efficiently find optimized interactions for a wide range of possible chemical potential constraints. We find that assemblies designed to exhibit a large chemical potential advantage at a specified density have a smaller overall range of densities for which they are stable. This trend can be understood by considering the separation-dependent features of the pair potential and its gradient required to enhance the stability of the target structure relative to competitors. Using molecular dynamics simulations, we further show that potentials designed with larger chemical potential advantages exhibit higher melting temperatures.

  4. Indirect plant-parasitoid interactions mediated by changes in herbivore physiology.

    PubMed

    Kaplan, Ian; Carrillo, Juli; Garvey, Michael; Ode, Paul J

    2016-04-01

    In occupying an intermediate trophic position, herbivorous insects serve a vital link between plants at the base of the food chain and parasitoids at the top. Although these herbivore-mediated indirect plant-parasitoid interactions are well-documented, new studies have uncovered previously undescribed mechanisms that are fundamentally changing how we view tri-trophic relationships. In this review we highlight recent advances in this field focusing on both plant-driven and parasitoid-driven outcomes that flow up and down the trophic web, respectively. From the bottom-up, plant metabolites can impact parasitoid success by altering host immune function; however, few have considered the potential effects of other plant defense strategies such as tolerance on parasitoid ecology and behavior. From the top-down, parasitoids have long been considered plant bodyguards, but in reality the consequences of parasitism for herbivory rates and induction of plant defensive chemistry are far more complicated with cascading effects on community-level interactions. PMID:27436656

  5. Temperature and Soil Moisture Interactions in Quantifying Corn Yield Responses to Climate Change

    NASA Astrophysics Data System (ADS)

    Urban, D.; Lobell, D. B.

    2011-12-01

    Corn yields have been shown to decline nonlinearly under particularly hot growing season conditions, and quantifying potential yield variability under different climate change scenarios remains a key question for global food security. Evidence from both empirical studies and process-based crop models suggest that in addition to the nonlinear effects of temperature on yield, an interaction between soil moisture and temperature might also be present. Exceptionally dry soils exacerbate the negative effect of high temperatures on yields, while high moisture content can buffer against heat stress, thereby mitigating yield loss. Precipitation has so far been an important variable in modeling yields because it acts as a proxy for soil moisture, which is more directly correlated with a crop's productivity, and because more reliable historical data exist for precipitation than for soil moisture. Furthermore, temperature and precipitation interact in complex ways in determining soil moisture, and hydrologic models are therefore needed to estimate soil moisture levels if these are to be incorporated into a statistical crop model based on historical data. We combine such a statistical model of corn yields in the U.S., downscaled and bias corrected temperature and precipitation outputs of 15 different climate models, and soil moisture datasets to quantify the importance of soil moisture in predicting yields. We also analyze the sensitivity of these results to the uncertainties associated with soil moisture measurement error and climate model spread.

  6. Impacts of Aerosol-Cloud Interactions on Climate Change in East Asia

    NASA Astrophysics Data System (ADS)

    Shim, S.; Jung, Y.; Baek, H.; Cho, C.

    2013-12-01

    Climate impact by anthropogenic drivers gives high concerns in climate change simulation. IPCC AR4 emphasized the role of aerosol on climate besides the GHGs due to its negative significant radiative forcing. We find that climate feedback of anthropogenic aerosols over East Asia through direct and indirect (aerosol-cloud interaction) radiative process using HadGEM2-AO developed by the UK Met office. Due to the industrial revolution and population growth, total anthropogenic aerosol emissions have grown dramatically over East Asia; sulfate aerosol is the dominant component accounting for about 50% of total aerosol optical depth at 550nm (Figure 1). An increased amount of aerosols might increase the CCN number concentration and lead to more, but smaller, cloud droplets for fixed liquid water content. This increases the albedo of the cloud, resulting in enhance reflection and a cooling effect. And smaller drops require longer growth times to reach size at which they easily fall as precipitation. This effect called the cloud lifetime effect may enhance the cloud cover (Figure 2), with a persistent positive correlation between cloud cover and aerosol optical depth. Particularly, aerosols have an influence on the amount of cloud cover (SC, ST, and NS) through the interaction with precipitation efficiency of low level clouds. As a result of perturbations of East Asia aerosols from preindustrial to present day, a net radiative flux at the top of atmosphere is estimated to be -4 W/m2, with a regional mean surface cooling of 1.2 K. More detailed analysis will be shown at the conference. Fig. 1. (a) Total AOD distributions (b) Changes in decadal mean AOD over East Asia. Fig 2. Cloud cover distributions classified by ISCCP cloud types.

  7. The role of ocean-atmosphere interaction in shaping climate change in the North Atlantic sector

    NASA Astrophysics Data System (ADS)

    Hand, Ralf; Nour-Eddine, Omrani; Keenlyside Noel, S.; Richard, Greatbatch

    2015-04-01

    Here, we present an analysis of North Atlantic ocean-atmosphere interaction in a warming climate, based on a long-term coupled general circulation model experiment forced by the RCP 8.5 (Representative Concentration Pathways 8.5) scenario. In addition to globally strongly increased SSTs as a direct response to the radiative forcing, the model run shows a distinct change of the local sea surface temperature (SST hereafter) pattern in the Gulf Stream region. This includes changes of the SST gradients in the region of the Gulf Stream SST front, likely as a response of the wind-driven part of the oceanic surface circulation. As a consequence of a massive slow-down of the Atlantic Meridional Overturning Circulation the northern North Atlantic furthermore shows a much weaker warming than the other oceans. The feedback of these changes on the atmosphere was studied in a set of sensitivity experiments based on the SST climatology of the coupled runs. The set consists of four runs: a control experiment based on the historical run, a run using the full SST from coupled RCP 8.5 run and two runs, where where we deconstructed the SST signal into a homogenous mean warming part and a local SST pattern change. In the region of the precipitation maximum in the historical run the future scenario shows an increase of absolute SSTs, but a a significant decrease in local precipitation. We show evidence that the local response in that region is connected to the (with respect to the historical run) weakened SST gradients rather than to the absolute SST. Consistently, the model shows enhanced precipitation north of this region, where the SST gradients are enhanced. The warming causes a decreased low-level convergence and upward motion in the region with reduced SST gradient. However, the signal restricts to the low and mid-troposphere and does not reach the higher model levels. There is little evidence for a large-scale response to the SST pattern changes in the Gulf Stream region

  8. Entertainment-Education and Social Change: An Analysis of Parasocial Interaction, Social Learning, Collective Efficacy, and Paradoxical Communication.

    ERIC Educational Resources Information Center

    Papa, Michael J.; Singhal, Arvind; Law, Sweety; Pant, Saumya; Sood, Suruchi; Rogers, Everett M.; Shefner-Rogers, Corinne L.

    2000-01-01

    Explores processes of social change initiated by an entertainment-education radio soap opera by studying its effects in an observational case study in one rural village in India. Investigates the paradoxes, contradictions, and audience members' struggles in the process of media-stimulated change, a process involving parasocial interaction, peer…

  9. Interacting effects of climate change and habitat fragmentation on drought-sensitive butterflies

    NASA Astrophysics Data System (ADS)

    Oliver, Tom H.; Marshall, Harry H.; Morecroft, Mike D.; Brereton, Tom; Prudhomme, Christel; Huntingford, Chris

    2015-10-01

    Climate change is expected to increase the frequency of some climatic extremes. These may have drastic impacts on biodiversity, particularly if meteorological thresholds are crossed, leading to population collapses. Should this occur repeatedly, populations may be unable to recover, resulting in local extinctions. Comprehensive time series data on butterflies in Great Britain provide a rare opportunity to quantify population responses to both past severe drought and the interaction with habitat area and fragmentation. Here, we combine this knowledge with future projections from multiple climate models, for different Representative Concentration Pathways (RCPs), and for simultaneous modelled responses to different landscape characteristics. Under RCP8.5, which is associated with `business as usual’ emissions, widespread drought-sensitive butterfly population extinctions could occur as early as 2050. However, by managing landscapes and particularly reducing habitat fragmentation, the probability of persistence until mid-century improves from around zero to between 6 and 42% (95% confidence interval). Achieving persistence with a greater than 50% chance and right through to 2100 is possible only under both low climate change (RCP2.6) and semi-natural habitat restoration. Our data show that, for these drought-sensitive butterflies, persistence is achieved more effectively by restoring semi-natural landscapes to reduce fragmentation, rather than simply focusing on increasing habitat area, but this will only be successful in combination with substantial emission reductions.

  10. Groundwater-surface water interactions in the hyporheic zone under climate change scenarios.

    PubMed

    Zhou, Shangbo; Yuan, Xingzhong; Peng, Shuchan; Yue, Junsheng; Wang, Xiaofeng; Liu, Hong; Williams, D Dudley

    2014-12-01

    Slight changes in climate, such as the rise of temperature or alterations of precipitation and evaporation, will dramatically influence nearly all freshwater and climate-related hydrological behavior on a global scale. The hyporheic zone (HZ), where groundwater (GW) and surface waters (SW) interact, is characterized by permeable sediments, low flow velocities, and gradients of physical, chemical, and biological characteristics along the exchange flows. Hyporheic metabolism, that is biogeochemical reactions within the HZ as well as various processes that exchange substances and energy with adjoining systems, is correlated with hyporheic organisms, habitats, and the organic matter (OM) supplied from GW and SW, which will inevitably be influenced by climate-related variations. The characteristics of the HZ in acting as a transition zone and in filtering and purifying exchanged water will be lost, resulting in a weakening of the self-purification capacity of natural water bodies. Thus, as human disturbances intensify in the future, GW and SW pollution will become a greater challenge for mankind than ever before. Biogeochemical processes in the HZ may favor the release of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) under climate change scenarios. Future water resource management should consider the integrity of aquatic systems as a whole, including the HZ, rather than independently focusing on SW and GW. PMID:25081003

  11. The Future Interaction of Science and Innovation Policy for Climate Change and National Security

    SciTech Connect

    Malone, Elizabeth L.; Cowell, Andrew J.; Riensche, Roderick M.

    2009-10-01

    Recent efforts to characterize the interactions among climate change and national security issues raise challenges of relating disparate bodies of scientific (both physical and social) knowledge as well as determining the role of innovation in meeting these challenges. Technological innovation has been called for to combat climate change, increase food production, and discover new ways of generating energy, and proposals for increased investments in R&D and technology deployment are to be met with everywhere. However, such policy decisions in one domain have impacts in other domains—often unexpected, often negative, but often capable of being addressed in planning stages. The technological tools described here allow users to embody the knowledge of different domains, to keep that knowledge up to date, and to define relationships, via both a model and an analytic game, such that policymakers can foresee problems and plan to forestall or mitigate them. Capturing and dynamically updating knowledge is the accomplishment of the Knowledge Encapsulation Framework. A systems dynamic model, created in STELLA®, simulates the relationships among different domains, so that relevant knowledge is applied to a seemingly independent issue. An analytic game provides a method to use that knowledge as it might be used in real-world settings.

  12. Plant–pathogen interactions and elevated CO2: morphological changes in favour of pathogens

    PubMed Central

    Lake, Janice Ann; Wade, Ruth Nicola

    2009-01-01

    Crop losses caused by pests and weeds have been estimated at 42% worldwide, with plant pathogens responsible for almost $10 billion worth of damage in the USA in 1994 alone. Elevated carbon dioxide [ECO2] and associated climate change have the potential to accelerate plant pathogen evolution, which may, in turn, affect virulence. Plant–pathogen interactions under increasing CO2 concentrations have the potential to disrupt both agricultural and natural systems severely, yet the lack of experimental data and the subsequent ability to predict future outcomes constitutes a fundamental knowledge gap. Furthermore, nothing is known about the mechanistic bases of increasing pathogen agressiveness. In the absence of information on crop species, it is shown here that plant pathogen (Erysiphe cichoracearum) aggressiveness is increased under ECO2, together with changes in the leaf epidermal characteristics of the model plant Arabidopsis thaliana L. Stomatal density, guard cell length, and trichome numbers on leaves developing post-infection are increased under ECO2 in direct contrast to non-infected responses. As many plant pathogens utilize epidermal features for successful infection, these responses provide a positive feedback mechanism facilitating an enhanced susceptibility of newly developed leaves to further pathogen attack. Furthermore, a screen of resistant and susceptible ecotypes suggest inherent differences in epidermal responses to ECO2. PMID:19470658

  13. Interactive effects of global and regional change on a coastal ecosystem

    NASA Astrophysics Data System (ADS)

    Reise, Karsten; van Beusekom, Justus E. E.

    2008-03-01

    Shallow waters and lowland meet at the same level in the Wadden Sea, but are separated by walls of coastal defense. What are the prospects of this coastal ecosystem in a warmer world? We focus on tidal waters and inshore sedimentary bottoms, expect nutrient supply from land to decline and species introductions, temperature and sea level to rise. The effects are interrelated and will have an increasing likelihood of abrupt and irreversible developments. The biotic interactions are hardly predictable but we anticipate the following changes to be more likely than others: blooms of phytoplankton will be weak mainly because of increasing pelagic and benthic grazing pressure, both facilitated by warming. Possibly birds feeding on mollusks will encounter decreasing resource availability while fish-eaters benefit. Extensive reefs of Pacific oysters could facilitate aquatic macrophytes. Sea level rise and concomitant hydrodynamics above tidal flats favor well-anchored suspension feeders as well as burrowing fauna adapted to dynamic permeable sand. With high shares of immigrants from overseas and the south, species richness will increase; yet the ecosystem stability may become lower. We suggest that for the next decades invasions of introduced species followed by warming and declining nutrient supply will be the most pressing factor on the changes in the Wadden Sea ecosystem, and the effects of sea level rise to be the key issue on the scale of the whole century and beyond.

  14. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2007.

    PubMed

    2008-01-01

    This year the Montreal Protocol celebrates its 20th Anniversary. In September 1987, 24 countries signed the Montreal Protocol on Substances that Deplete the Ozone Layer. Today 191 countries have signed and have met strict commitments on phasing out of ozone depleting substances with the result that a 95% reduction of these substances has been achieved. The Montreal Protocol has also contributed to slowing the rate of global climate change, since most of the ozone depleting substances are also effective greenhouse gases. Even though much has been achieved, the future of the stratospheric ozone layer relies on full compliance of the Montreal Protocol by all countries for the remaining substances, including methyl bromide, as well as strict monitoring of potential risks from the production of substitute chemicals. Also the ozone depleting substances existing in banks and equipment need special attention to prevent their release to the stratosphere. Since many of the ozone depleting substances already in the atmosphere are long-lived, recovery cannot be immediate and present projections estimate a return to pre-1980 levels by 2050 to 2075. It has also been predicted that the interactions of the effects of the ozone layer and that of other climate change factors will become increasingly important. PMID:18274006

  15. Direct and indirect effects of climate change on soil microbial and soil microbial-plant interactions: What lies ahead?

    DOE PAGESBeta

    Classen, Aimée T.; Sundqvist, Maja K.; Henning, Jeremiah A.; Newman, Gregory S.; Moore, Jessica A. M.; Cregger, Melissa A.; Moorhead, Leigh C.; Patterson, Courtney M.

    2015-08-07

    Global change is altering species distributions and thus interactions among organisms. Organisms live in concert with thousands of other species, some beneficial, some pathogenic, some which have little to no effect in complex communities. Since natural communities are composed of organisms with very different life history traits and dispersal ability it is unlikely they will all respond to climatic change in a similar way. Disjuncts in plant-pollinator and plant-herbivore interactions under global change have been relatively well described, but plant-soil microorganism and soil microbe-microbe relationships have received less attention. Since soil microorganisms regulate nutrient transformations, provide plants with nutrients, allowmore » co-existence among neighbors, and control plant populations, changes in soil microorganism-plant interactions could have significant ramifications for plant community composition and ecosystem function. Finally, in this paper we explore how climatic change affects soil microbes and soil microbe-plant interactions directly and indirectly, discuss what we see as emerging and exciting questions and areas for future research, and discuss what ramifications changes in these interactions may have on the composition and function of ecosystems.« less

  16. Direct and indirect effects of climate change on soil microbial and soil microbial-plant interactions: What lies ahead?

    SciTech Connect

    Classen, Aimée T.; Sundqvist, Maja K.; Henning, Jeremiah A.; Newman, Gregory S.; Moore, Jessica A. M.; Cregger, Melissa A.; Moorhead, Leigh C.; Patterson, Courtney M.

    2015-08-07

    Global change is altering species distributions and thus interactions among organisms. Organisms live in concert with thousands of other species, some beneficial, some pathogenic, some which have little to no effect in complex communities. Since natural communities are composed of organisms with very different life history traits and dispersal ability it is unlikely they will all respond to climatic change in a similar way. Disjuncts in plant-pollinator and plant-herbivore interactions under global change have been relatively well described, but plant-soil microorganism and soil microbe-microbe relationships have received less attention. Since soil microorganisms regulate nutrient transformations, provide plants with nutrients, allow co-existence among neighbors, and control plant populations, changes in soil microorganism-plant interactions could have significant ramifications for plant community composition and ecosystem function. Finally, in this paper we explore how climatic change affects soil microbes and soil microbe-plant interactions directly and indirectly, discuss what we see as emerging and exciting questions and areas for future research, and discuss what ramifications changes in these interactions may have on the composition and function of ecosystems.

  17. Interactive effects of reactive nitrogen and climate change on US water resources

    NASA Astrophysics Data System (ADS)

    Baron, J.; Bernhardt, E. S.; Finlay, J. C.; Chan, F.; Nolan, B. T.; Howarth, B.; Hall, E.; Boyer, E. W.

    2011-12-01

    Water resources and aquatic ecosystems are increasingly strained by withdrawals for agriculture and drinking water supply, nitrogen and other pollutant inputs, and climate change. We describe current and projected effects of the interactions of reactive nitrogen (N) and climate change on water resources of the United States. As perturbations to the N cycle intensify in a warmer less predictable climate, interactions will negatively affect the services we expect of our water resources. There are also feedbacks to the climate system itself through the production of greenhouse gases. We conclude: 1. Nitrogen concentrations will increase in the nation's waters from increased N loading and higher N mineralization rates. N export from terrestrial to aquatic ecosystems exhibits a high sensitivity to climate variations. 2. Consequences range from eutrophication and acidification, which reduce natural biodiversity and harm economically valuable fisheries, to adverse impacts on human health. 3. Extreme flood events have the potential to transport N rapidly long distances downstream from its source. 4. A recent national assessment found 67% of streams derived more than 37% of their total nitrate load from base flow often derived from groundwater. Long residence times for groundwater nitrate below agricultural fields may cause benefits from proper N management practices to take decades to be realized under current and future climates. 5. Streams, wetlands, rivers, lakes, estuaries and continental shelves are hotspots for denitrification. Maintenance of N removal capacity thus a critical component of eutrophication management under changing climate and land use conditions. 6. The amount of N inputs from fertilizer and manure use, human population, and deposition is tightly coupled with hydrology to influence the rates and proportion of N emitted to the atmosphere as N2O. About 20% of global N2O emissions come from groundwater, lakes, rivers, and estuaries; stream and wetland

  18. Carboxy terminus heat shock protein 70 interacting protein reduces tau-associated degenerative changes.

    PubMed

    Saidi, Laiq-Jan; Polydoro, Manuela; Kay, Kevin R; Sanchez, Laura; Mandelkow, Eva-Maria; Hyman, Bradley T; Spires-Jones, Tara L

    2015-01-01

    One of the hallmarks of Alzheimer's disease is the formation of neurofibrillary tangles, intracellular aggregates of hyperphosphorylated, mislocalized tau protein, which are associated with neuronal loss. Changes in tau are known to impair cellular transport (including that of mitochondria) and are associated with cell death in cell culture and mouse models of tauopathy. Thus clearing pathological forms of tau from cells is a key therapeutic strategy. One critical modulator in the degradation and clearance of misfolded proteins is the co-chaperone CHIP (Carboxy terminus Hsp70 interacting Protein), which is known to play a role in refolding and clearance of hyperphosphorylated tau. Here, we tested the hypothesis that CHIP could ameliorate pathological changes associated with tau. We find that co-expressing CHIP with full-length tau, tau truncated at D421 mimicking caspase cleavage, or the short tauRDΔK280 tau construct containing only the tau repeat domain with a tauopathy mutation, decreases tau protein levels in human H4 neuroglioma cells in a manner dependent on the Hsp70-binding TPR domain of CHIP. The observed reduction in tau levels by CHIP is associated with a decrease of tau phosphorylation and reduced levels of cleaved Caspase 3 indicating that CHIP plays an important role in preventing tau-induced pathological changes. Furthermore, tau-associated mitochondrial transport deficits are rescued by CHIP co-expression in H4 cells. Together, these data suggest that the co-chaperone CHIP can rescue the pathological effects of tau, and indicate that other diseases of protein misfolding and accumulation may also benefit from CHIP upregulation. PMID:25374103

  19. Climate change threatens endangered plant species by stronger and interacting water-related stresses

    NASA Astrophysics Data System (ADS)

    Bartholomeus, Ruud P.; Witte, Jan-Philip M.; van Bodegom, Peter M.; van Dam, Jos C.; Aerts, Rien

    2011-12-01

    Atmospheric CO2-concentration, temperature and rainfall variability are all expected to increase in the near future. The resulting increased dynamics of soil moisture contents, together with increased plant physiological demands for both oxygen and water, will lead to an increased occurrence of wet and dry extremes of plant stresses, i.e., of oxygen and drought stress, respectively, alone and in interaction. The use of indirect environmental variables in previous studies and a focus on individual stresses rather than their combined effects has hampered understanding of the causal impact of climate change on plant species composition through changes in abiotic site conditions. Here, we use process-based simulations of oxygen and drought stresses in conjunction with a downscaled national version of IPCC scenarios in order to show that these stresses will increase (on average by ˜20% at sites where both stresses occur) in a warmer and more variable future (2050) climate. These two types of stresses will increasingly coincide, i.e. both stresses will occur more often (but not at the same time) within a single vegetation plot. We further show that this increased coincidence of water-related stresses will negatively affect the future occurrence of currently endangered plant species (causing a reduction of ˜16%), while apparently no such decrease will occur among common species. Individual stresses did not appear to affect the occurrence of endangered plant species. Consequently, our study demonstrates that species that are already threatened under the current climate will suffer most from the effects of climate change.

  20. Impacts of aerosol-cloud interactions on past and future changes in tropospheric composition

    SciTech Connect

    Unger, N.; Menon, S.; Shindell, D. T.; Koch, D. M.

    2009-02-02

    The development of effective emissions control policies that are beneficial to both climate and air quality requires a detailed understanding of all the feedbacks in the atmospheric composition and climate system. We perform sensitivity studies with a global atmospheric composition-climate model to assess the impact of aerosols on tropospheric chemistry through their modification on clouds, aerosol-cloud interactions (ACI). The model includes coupling between both tropospheric gas-phase and aerosol chemistry and aerosols and liquid-phase clouds. We investigate past impacts from preindustrial (PI) to present day (PD) and future impacts from PD to 2050 (for the moderate IPCC A1B scenario) that embrace a wide spectrum of precursor emission changes and consequential ACI. The aerosol indirect effect (AIE) is estimated to be -2.0 Wm{sup -2} for PD-PI and -0.6 Wm{sup -2} for 2050-PD, at the high end of current estimates. Inclusion of ACI substantially impacts changes in global mean methane lifetime across both time periods, enhancing the past and future increases by 10% and 30%, respectively. In regions where pollution emissions increase, inclusion of ACI leads to 20% enhancements in in-cloud sulfate production and {approx}10% enhancements in sulfate wet deposition that is displaced away from the immediate source regions. The enhanced in-cloud sulfate formation leads to larger increases in surface sulfate across polluted regions ({approx}10-30%). Nitric acid wet deposition is dampened by 15-20% across the industrialized regions due to ACI allowing additional re-release of reactive nitrogen that contributes to 1-2 ppbv increases in surface ozone in outflow regions. Our model findings indicate that ACI must be considered in studies of methane trends and projections of future changes to particulate matter air quality.

  1. Fostering Environmental Literacy For A Changing Earth: Interactive and Participatory Outreach Programs at Biosphere 2

    NASA Astrophysics Data System (ADS)

    Pavao-Zuckerman, M.; Huxman, T.; Morehouse, B.

    2008-12-01

    Earth system and ecological sustainability problems are complex outcomes of biological, physical, social, and economic interactions. A common goal of outreach and education programs is to foster a scientifically literate community that possesses the knowledge to contribute to environmental policies and decision making. Uncertainty and variability that is both inherent in Earth system and ecological sciences can confound such goals of improved ecological literacy. Public programs provide an opportunity to engage lay-persons in the scientific method, allowing them to experience science in action and confront these uncertainties face-on. We begin with a definition of scientific literacy that expands its conceptualization of science beyond just a collection of facts and concepts to one that views science as a process to aid understanding of natural phenomena. A process-based scientific literacy allows the public, teachers, and students to assimilate new information, evaluate climate research, and to ultimately make decisions that are informed by science. The Biosphere 2 facility (B2) is uniquely suited for such outreach programs because it allows linking Earth system and ecological science research activities in a large scale controlled environment setting with outreach and education opportunities. A primary outreach goal is to demonstrate science in action to an audience that ranges from K-12 groups to retired citizens. Here we discuss approaches to outreach programs that focus on soil-water-atmosphere-plant interactions and their roles in the impacts and causes of global environmental change. We describe a suite of programs designed to vary the amount of participation a visitor has with the science process (from passive learning to data collection to helping design experiments) to test the hypothesis that active learning fosters increased scientific literacy and the creation of science advocates. We argue that a revised framing of the scientific method with a more

  2. Human-water interactions in Myanmar's Dry Zone under climate change

    NASA Astrophysics Data System (ADS)

    Taft, Linda; Evers, Mariele

    2016-04-01

    Understanding human-water interactions is particularly essential in countries where the economy and the people's well-being and income strongly depend on the availability and quality of sufficient water resources. Such a strong dependency on water is existent in Myanmar's Dry Zone located in the central Ayeyarwady River basin. In this area, rainfall is associated with high heterogeneity across space and time. Precipitation amounts in the Dry Zone (500-1000 mm annually) are generally less compared to other regions in Myanmar (up to 4000-6000 mm). Following the Global Climate Risk Index, Myanmar is one of the countries which were most affected by extreme weather events between 1994 and 2013. Severe drought periods e.g in the years 1997-1998, 2010 and 2014 led to crop failures and water shortage in the Dry Zone, where more than 14 mio people predominantly practice agriculture. Due to the high variability of rainfalls, farming is only possible with irrigation, mainly conducted by canal systems from the rivers and groundwater withdrawal. Myanmar is recently facing big challenges which result from comprehensive political and economic reforms since 2011. These may also include increasing water use by new industrial zones and urbanization. However, not only policy and economy modify the need for water. Variability of river runoff and changes in seasonality are expected as a result of climate change. The overarching goal of the study is to understand and increase the knowledge on human-water-climate interactions and to elaborate possible future scenarios for Myanmar's Dry Zone. It is not well studied yet how current and future climate change and increasing human impact will influence the country's abundant water resources including groundwater. Therefore, the first step of this study is to identify the major drivers within the central Ayeyarwady River basin. We are in the process of collecting and analyzing data sets and information including hydrologic and eco

  3. Changes in the sexual behavior and testosterone levels of male rats in response to daily interactions with estrus females

    PubMed Central

    Shulman, Leanne M.; Spritzer, Mark D.

    2014-01-01

    Male rat sexual behavior has been intensively studied over the past 100 years, but few studies have examined how sexual behavior changes over the course of several days of interactions. In this experiment, adult male rats (n = 12) were given daily access to estrus females for 30 min per day for 15 consecutive days and control males did not interact with females. Ovariectomized females were induced into estrus with hormonal injections, and males interacted with a different female each day. The amount of sexual activity (mounts, intromissions, and ejaculations) was found to cycle with a period of approximately 4 days in most male rats. Additionally, blood was collected every other day following sexual interactions to assess serum testosterone levels. Testosterone was found to peak on the first day of interaction and then fell back to near the level of control rats that did not interact with females. Following the initial peak, testosterone concentrations fluctuated less in males exposed to females than in controls. Sexual activity was not found to predict testosterone concentration. We conclude that when male rats have daily sexual interactions, sexual behavior tends to show cyclic changes and testosterone is significantly elevated only on the first day of interactions. PMID:24813700

  4. Changes in the sexual behavior and testosterone levels of male rats in response to daily interactions with estrus females.

    PubMed

    Shulman, Leanne M; Spritzer, Mark D

    2014-06-22

    Male rat sexual behavior has been intensively studied over the past 100 years, but few studies have examined how sexual behavior changes over the course of several days of interactions. In this experiment, adult male rats in the experimental group (n=12) were given daily access to estrus females for 30 min per day for 15 consecutive days while control males (n=11) did not interact with females. Ovariectomized females were induced into estrus with hormonal injections, and males interacted with a different female each day. The amount of sexual activity (mounts, intromissions, and ejaculations) was found to cycle with a period of approximately 4 days in most male rats. Additionally, blood was collected every other day following sexual interactions to assess serum testosterone levels. Testosterone was found to peak on the first day of interaction and then fell back to near the level of control rats that did not interact with females. Following the initial peak, testosterone concentrations fluctuated less in males exposed to females than in controls. Sexual activity was not found to predict testosterone concentration. We conclude that when male rats have daily sexual interactions, sexual behavior tends to show cyclic changes and testosterone is significantly elevated only on the first day of interactions. PMID:24813700

  5. Classroom Demonstration and Interactive Model of Sea-Level Control on Lateral and Vertical Facies Changes

    NASA Astrophysics Data System (ADS)

    Smith, C.; Pound, K. S.; Jones, M. H.; Schmitt, L.; Campbell, K.

    2005-12-01

    Students often have difficulty understanding and visualizing the role that relative sea-level change plays in controlling vertical and lateral facies changes; they also struggle with explanations of regional facies patterns and changes as sea-level dependant. This interactive, dynamic, in-class model has been developed to build their understanding both of this topic, and of the nature of predictive scientific models. The model can be used as a follow-up to field observations, or to pre-teach concepts. The model assumes a land-ocean transect that is divided into 5 sedimentary settings. Each setting in the land-ocean transect is associated with sediment grain size that decreases basinward; the most basinward component is carbonate. In the model, seven 10-cm diameter see-through tubes are set up to represent `cores' spread along the land-ocean transect. Brightly-colored plastic beads are used to represent sediment deposited in each of the sedimentary settings. At the start, the position of the shoreline (sea level) is fixed between the fluvial (tube 2) and beach (tube 3) sediments. Students then deposit beads that represent their sediment type in the each tube. Other students control the sea-level marker, which can be raised or lowered, and students with the sediment (beads) move shoreward or basinward accordingly, and deposit their sediments (beads) in the appropriate tube. This produces a simple visual record (tubes with layers of distinctly colored beads) that show the idealized sedimentary consequences of relative sea-level change. After large-scale patterns in facies changes have been demonstrated and discussed, students can manipulate variables such as supply and rate. Students can fill a basin using a sequence of events they determine, and other student groups can interpret their cores. The learning and approach of this model can be extended to include real sediment (gravel, sand, silt, mud) deposited in cardboard tubes that are then opened and treated as cores

  6. Terrestrial ecosystems, increased solar ultraviolet radiation, and interactions with other climate change factors.

    PubMed

    Caldwell, M M; Bornman, J F; Ballaré, C L; Flint, S D; Kulandaivelu, G

    2007-03-01

    , such as diminished growth, acclimation responses of plants to UV-B radiation and interactions of plants with consumer organisms such as insects and plant pathogens. The response to UV-B radiation involves both the initial stimulus by solar radiation and transmission of signals within the plants. Resulting changes in gene expression induced by these signals may have elements in common with those elicited by other environmental factors, and generate overlapping functional (including acclimation) responses. Concurrent responses of terrestrial systems to the combination of enhanced UV-B radiation and other global change factors (increased temperature, CO2, available nitrogen and altered precipitation) are less well understood. Studies of individual plant responses to combinations of factors indicate that plant growth can be augmented by higher CO2 levels, yet many of the effects of UV-B radiation are usually not ameliorated by the elevated CO2. UV-B radiation often increases both plant frost tolerance and survival under extreme high temperature conditions. Conversely, extreme temperatures sometimes influence the UV-B radiation sensitivity of plants directly. Plants that endure water deficit stress effectively are also likely to be tolerant of high UV-B flux. Biologically available nitrogen is exceeding historical levels in many regions due to human activities. Studies show that plants well supplied with nitrogen are generally more sensitive to UV-B radiation. Technical issues concerning the use of biological spectral weighting functions (BSWFs) have been further elucidated. The BSWFs, which are multiplication factors assigned to different wavelengths giving an indication of their relative biological effectiveness, are critical to the proper conduct and interpretation of experiments in which organisms are exposed to UV radiation, both in the field and in controlled environment facilities. The characteristics of BSWFs vary considerably among different plant processes, such

  7. BISPHENOL A EXPOSURE DURING EARLY DEVELOPMENT INDUCES SEX-SPECIFIC CHANGES IN ADULT ZEBRAFISH SOCIAL INTERACTIONS

    PubMed Central

    Weber, Daniel N.; Hoffmann, Raymond G.; Hoke, Elizabeth S.; Tanguay, Robert L.

    2014-01-01

    Developmental bisphenol A (BPA) exposure is associated with adverse behavioral effects, although underlying modes of action remain unclear. Because BPA is a suspected xenoestrogen, the objective was to identify sex-based changes in adult zebrafish social behavior developmentally exposed to BPA (0.0, 0.1 or 1 μM) or one of two control compounds (0.1μM 17β-estradiol [E2], and 0.1 μM GSK4716, a synthetic estrogen-related receptor γ ligand). A test chamber was divided lengthwise so each arena held one fish unable to detect the presence of the other fish. A mirror was inserted at one end of each arena; baseline activity levels were determined without mirror. Arenas were divided into 3, computer-generated zones to represent different distances from mirror image. Circadian rhythm patterns were evaluated at 1–3 (= AM) and 5–8 (= PM) hr postprandial. Adult zebrafish were placed into arenas and monitored by digital camera for 5 min. Total distance traveled, % time spent at mirror image, and number of attacks on mirror image were quantified. E2, GSK4716, and all BPA treatments dampened male activity and altered male circadian activity patterns; there was no marked effect on female activity. BPA induced non-monotonic effects (response curve changes direction within range of concentrations examined) on male % time at mirror only in AM. All treatments produced increased % time at the mirror during PM. Male attacks on the mirror were reduced by BPA exposure only during AM. There were sex-specific effects of developmental BPA on social interactions and time-of-day of observation affected results. PMID:25424546

  8. The Effectiveness of Parent-Child Interaction Therapy with Depressive Mothers: The Changing Relationship as the Agent of Individual Change

    ERIC Educational Resources Information Center

    Timmer, Susan G.; Ho, Lareina K. L.; Urquiza, Anthony J.; Zebell, Nancy M.; Fernandez y Garcia, Erik; Boys, Deanna

    2011-01-01

    This study uses a multi-method approach to investigate the effectiveness of Parent-Child Interaction Therapy (PCIT) in reducing children's behavior problems when parents report clinical levels of depressive symptoms. Participants were 132 children, 2-7 years of age, and their biological mothers, who either reported low (N = 78) or clinical levels…

  9. Changes in chemical interactions and protein conformation during heat-induced wheat gluten gel formation.

    PubMed

    Wang, Kai-Qiang; Luo, Shui-Zhong; Zhong, Xi-Yang; Cai, Jing; Jiang, Shao-Tong; Zheng, Zhi

    2017-01-01

    In order to elucidate the heat-induced wheat gluten gel formation mechanism, changes in chemical interactions and protein conformation were investigated during gelation. The contribution of ionic and hydrogen bonds were found to decrease from 0.746 and 4.133g/L to 0.397 and 2.733g/L, respectively, as the temperature increased from 25 to 90°C. Moreover, the free SH content remarkably decreased from 37.91 to 19.79μmol/g during gelation. Ultraviolet absorption spectra and intrinsic fluorescence spectra suggested that wheat gluten unfolded during the heating process. In addition, wheat gluten gels treated at 80 and 90°C exhibited a "steric hindrance" effect, which can be attributed to the formation of aggregates. Fourier transform infrared spectra suggested that the random coil content increased at low temperatures (40 and 50°C), whereas the content of intermolecular β-sheets due to protein aggregation increased from 38.10% to 44.28% when the gelation temperature was 90°C. PMID:27507490

  10. Health effects from stratospheric ozone depletion and interactions with climate change.

    PubMed

    de Gruijl, Frank R; Longstreth, Janice; Norval, Mary; Cullen, Anthony P; Slaper, Harry; Kripke, Margaret L; Takizawa, Yukio; van der Leun, Jan C

    2003-01-01

    The potential health effects of elevated levels of ambient UV-B radiation are diverse, and it is difficult to quantify the risks, especially as they are likely to be considerably modified by human behaviour. Nevertheless epidemiological and experimental studies have confirmed that UV radiation is a definite risk factor for certain types of cataract, with peak efficacy in the UV-B waveband. The causal link between squamous cell carcinoma and cumulative solar UV exposure has been well established. New findings regarding the genetic basis of skin cancer, including studies on genetically modified mice, have confirmed the epidemiological evidence that UV radiation contributes to the formation of basal cell carcinomas and cutaneous melanomas, For the latter, animal models have demonstrated that UV exposure at a very young age is more detrimental than exposure in adulthood. Although suppression of certain immune responses has been recognised following UV exposure, the impact of this suppression on the control of infectious and autoimmune diseases is largely unknown. However, studies on several microbial infections have indicated significant consequences in terms of symptoms or reactivation of disease. The possibility that the immune response to vaccination could be depressed by UV-B exposure is of considerable concern. Newly emerging possibilities regarding interactions between ozone depletion and global climate change further complicate the risk assessments for human health but might result in an increased incidence of cataracts and skin cancer, plus alterations in the patterns of certain categories of infectious and other diseases. PMID:12659536

  11. Integrated analysis of ecosystem interactions with land use Change: The Chesapeake Bay watershed

    NASA Astrophysics Data System (ADS)

    Goetz, Scott J.; Jantz, Claire A.; Prince, Stephen D.; Smith, Andrew J.; Varlyguin, Dmitry; Wright, Robb K.

    The Chesapeake Bay is the largest estuary in the United States, encompassed by a watershed extending 168,000 km2 over portions of six states and Washington, D.C. Restoration of the Bay has been the focus of a two-decade regional partnership of local, state and federal agencies, including a network of scientists, politicians and activists interacting through various committees, working groups, and advisory panels. The effectiveness of the restoration effort has been mixed, with both notable successes and failures. The overall health of the Bay has not declined since the restoration was initiated in 1983, but many of the advances have been offset by the pressure of increasing population and exurban sprawl across the watershed. The needs of the Chesapeake Bay Program are many, but the greatest is accurate information on land cover and land use change, primarily to assess the implications for water quality, examine various restoration scenarios, and calibrate spatial models of the urbanization process. We report here on a number of new land cover and land use data products, and associated applications to assist vulnerability assessment, integrated ecosystem analysis, and ultimately Bay restoration. We provide brief overviews of applications to model new residential development, assess losses and vulnerability of resource lands, and identify the factors that disrupt the health of streams in small watersheds. These data products and approaches are being applied by a number of agencies involved with the restoration effort, including the Chesapeake Bay Program's activities focused on living resources, water quality, and sound land use.

  12. A mutation within the transmembrane domain of melanosomal protein Silver (Pmel17) changes lumenal fragment interactions

    PubMed Central

    Kuliawat, Regina; Santambrogio, Laura

    2009-01-01

    Melanocytes synthesize and store melanin within tissue-specific organelles, the melanosomes. Melanin deposition takes place along fibrils found within these organelles and fibril formation is known to depend on trafficking of the membrane glycoprotein Silver/Pmel17. However, correctly targeted, full-length Silver/Pmel17 cannot form fibers. Proteolytic processing in endosomal compartments and the generation of a lumenal Mα fragment that is incorporated into amyloid-like structures is also essential. Dominant White (DWhite), a mutant form of Silver/Pmel17 first described in chicken, causes disorganized fibers and severe hypopigmentation due to melanocyte death. Surprisingly, the DWhite mutation is an insertion of three amino acids into the transmembrane domain; the DWhite-Mα fragment is unaffected. To determine the functional importance of the transmembrane domain in organized fibril assembly, we investigated membrane trafficking and multimerization of Silver/Pmel17/DWhite proteins. We demonstrate that the DWhite mutation changes lipid interactions and disulfide bond-mediated associations of lumenal domains. Thus, partitioning into membrane microdomains and effects on conformation explain how the transmembrane region may contribute to the structural integrity of Silver/Pmel17 oligomers or influence toxic, amyloidogenic properties. PMID:19679373

  13. Yeast mitochondrial RNAP conformational changes are regulated by interactions with the mitochondrial transcription factor

    PubMed Central

    Drakulic, Srdja; Wang, Liping; Cuéllar, Jorge; Guo, Qing; Velázquez, Gilberto; Martín-Benito, Jaime; Sousa, Rui; Valpuesta, José M.

    2014-01-01

    Mitochondrial RNA polymerases (MtRNAPs) are members of the single-subunit RNAP family, the most well-characterized member being the RNAP from T7 bacteriophage. MtRNAPs are, however, functionally distinct in that they depend on one or more transcription factors to recognize and open the promoter and initiate transcription, while the phage RNAPs are capable of performing these tasks alone. Since the transcriptional mechanisms that are conserved in phage and mitochondrial RNAPs have been so effectively characterized in the phage enzymes, outstanding structure-mechanism questions concern those aspects that are distinct in the MtRNAPs, particularly the role of the mitochondrial transcription factor(s). To address these questions we have used both negative staining and cryo-EM to generate three-dimensional reconstructions of yeast MtRNAP initiation complexes with and without the mitochondrial transcription factor (MTF1), and of the elongation complex. Together with biochemical experiments, these data indicate that MTF1 uses multiple mechanisms to drive promoter opening, and that its interactions with the MtRNAP regulate the conformational changes undergone by the latter enzyme as it traverses the template strand. PMID:25183523

  14. Conformational Changes Leading to T7 DNA Delivery upon Interaction with the Bacterial Receptor*

    PubMed Central

    González-García, Verónica A.; Pulido-Cid, Mar; Garcia-Doval, Carmela; Bocanegra, Rebeca; van Raaij, Mark J.; Martín-Benito, Jaime; Cuervo, Ana; Carrascosa, José L.

    2015-01-01

    The majority of bacteriophages protect their genetic material by packaging the nucleic acid in concentric layers to an almost crystalline concentration inside protein shells (capsid). This highly condensed genome also has to be efficiently injected into the host bacterium in a process named ejection. Most phages use a specialized complex (often a tail) to deliver the genome without disrupting cell integrity. Bacteriophage T7 belongs to the Podoviridae family and has a short, non-contractile tail formed by a tubular structure surrounded by fibers. Here we characterize the kinetics and structure of bacteriophage T7 DNA delivery process. We show that T7 recognizes lipopolysaccharides (LPS) from Escherichia coli rough strains through the fibers. Rough LPS acts as the main phage receptor and drives DNA ejection in vitro. The structural characterization of the phage tail after ejection using cryo-electron microscopy (cryo-EM) and single particle reconstruction methods revealed the major conformational changes needed for DNA delivery at low resolution. Interaction with the receptor causes fiber tilting and opening of the internal tail channel by untwisting the nozzle domain, allowing release of DNA and probably of the internal head proteins. PMID:25697363

  15. Land-atmosphere interactions and climate change: Recent results and new perspectives (Invited)

    NASA Astrophysics Data System (ADS)

    Seneviratne, S. I.; Davin, E. L.; Greve, P.; Gudmundsson, L.; Guillod, B.; Hirschi, M.; Mittelbach, H.; Mueller, B.; Mystakidis, S.; Orlowsky, B.; Orth, R.; Wilhelm, M.

    2013-12-01

    simulations. Manuscript in preparation. Seneviratne, S.I., D. Lüthi, M. Litschi, and C. Schär, 2006: Land-atmosphere coupling and climate change in Europe. Nature, 443, 205-209. Seneviratne, S.I., T. Corti, E.L. Davin, M. Hirschi, E.B. Jaeger, I. Lehner, B. Orlowsky, and A.J. Teuling, 2010: Investigating soil moisture-climate interactions in a changing climate: A review. Earth-Science Reviews, 99, 3-4, 125-161, doi:10.1016/j.earscirev.2010.02.004. Seneviratne, S.I., M. Wilhelm, T. Stanelle, B.J.J.M. van den Hurk, S. Hagemann, A. Berg, F. Cheruy, M.E. Higgins, A. Meier, V. Brovkin, M. Claussen, A. Ducharne, J.-L. Dufresne, K.L. Findell, J. Ghattas, D.M. Lawrence, S. Malyshev, M. Rumukainen, and B. Smith, 2013: Impact of soil moisture-climate feedbacks on CMIP5 projections: First results from the GLACE-CMIP5 experiment. Submitted to Geophys. Res. Lett.

  16. Cross-scale Interactions and Changing Pattern-Process Relationships: Consequences for System Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cross-scale interactions occur either when fine-scale processes influence a broad spatial extent or a long time period, or when broad-scale drivers interact with fine-scale processes to determine system dynamics. Cross-scale interactions are increasing recognized as having important influences on e...

  17. Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change.

    PubMed

    Tomiolo, Sara; Van der Putten, Wim H; Tielbörger, Katja

    2015-05-01

    Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between climatically very different sites with simultaneous manipulation of soil, plant population origin, and neighbor conditions to evaluate local adaptation and possible adaptive response of four Eastern Mediterranean annual plant species to climate change. The effect of site on plant performance was negligible, but soil origin had a strong effect on fecundity, most likely due to differential water retaining ability. Competition by neighbors strongly reduced fitness. We separated the effects of the abiotic and biotic soil properties on plant performance by repeating the field experiment in a greenhouse under homogenous environmental conditions and including a soil biota manipulation treatment. As in the field, plant performance differed among soil origins and neighbor treatments. Moreover, we found plant species-specific responses to soil biota that may be best explained by the differential sensitivity to negative and positive soil biota effects. Overall, under the conditions of our experiment with two contrasting sites, biotic interactions had a strong effect on plant fitness that interacted with and eventually overrode climate. Because climate and biotic interactions covary, reciprocal transplants and climate gradient studies should consider soil biotic interactions and abiotic conditions when evaluating climate change effects on plant performance. PMID:26236843

  18. Dynamics of Defense Responses and Cell Fate Change during Arabidopsis-Pseudomonas syringae Interactions

    PubMed Central

    Hamdoun, Safae; Liu, Zhe; Gill, Manroop; Yao, Nan; Lu, Hua

    2013-01-01

    changes of defense phenotypes and cell fate determination during Arabidopsis-P. syringae interactions, contributing to a better understanding of plant defense mechanisms. PMID:24349466

  19. Dynamic changes in host-virus interactions associated with colony founding and social environment in fire ant queens (Solenopsis invicta).

    PubMed

    Manfredini, Fabio; Shoemaker, DeWayne; Grozinger, Christina M

    2016-01-01

    The dynamics of host-parasite interactions can change dramatically over the course of a chronic infection as the internal (physiological) and external (environmental) conditions of the host change. When queens of social insects found a colony, they experience changes in both their physiological state (they develop their ovaries and begin laying eggs) and the social environment (they suddenly stop interacting with the other members of the mother colony), making this an excellent model system for examining how these factors interact with chronic infections. We investigated the dynamics of host-viral interactions in queens of Solenopsis invicta (fire ant) as they transition from mating to colony founding/brood rearing to the emergence of the first workers. We examined these dynamics in naturally infected queens in two different social environments, where queens either founded colonies as individuals or as pairs. We hypothesized that stress associated with colony founding plays an important role in the dynamics of host-parasite interactions. We also hypothesized that different viruses have different modalities of interaction with the host that can be quantified by physiological measures and genomic analysis of gene expression in the host. We found that the two most prevalent viruses, SINV-1 and SINV-2, are associated with different fitness costs that are mirrored by different patterns of gene expression in the host. In fact SINV-2, the virus that imposes the significant reduction of a queen's reproductive output is also associated with larger changes of global gene expression in the host. These results show the complexity of interactions between S. invicta and two viral parasites. Our findings also show that chronic infections by viral parasites in insects are dynamic processes that may pose different challenges in the host, laying the groundwork for interesting ecological and evolutionary considerations. PMID:26811788

  20. Potential Effects of Climate Change on Ecological Interaction Outcomes Between Two Disease-Vector Mosquitoes: A Mesocosm Experimental Study.

    PubMed

    Leonel, B F; Koroiva, R; Hamada, N; Ferreira-Keppler, R L; Roque, F O

    2015-09-01

    The objective of this study was to experimentally assess the effects of different climate change scenarios on the outcomes of interactions between Aedes aegypti (L.) and Culex quinquefasciatus (Say) (Diptera: Culicidae) larvae. The experimental design maintained a constant density of specimens while the proportion of the species in different experimental climate change scenarios varied. Our results indicate that survival of the two species was not affected, but larval development and pupation times decreased under elevated atmospheric CO(2) concentration and high air temperature. In climate change scenarios with both species together, the survival of Ae. aegypti increased and its larval development time decreased with increasing density of Cx. quinquefasciatus. This may be attributed to the effects of intraspecific competition being more significant than interspecific competition in Ae. aegypti. Our study also reveals that climatic changes may affect the patterns of interactions between Cx. quinquefasciatus and Ae. aegypti. Alterations in climatic conditions changed the response of context-dependent competition, indicating the importance of studies on how ecological interactions will be affected by projected future climatic change. PMID:26336208

  1. An insulin based model to explain changes and interactions in human breath-holding.

    PubMed

    Dangmann, Rosita

    2015-06-01

    Until now oxygen was thought to be the leading factor of hypoxic conditions. Whereas now it appears that insulin is the key regulator of hypoxic conditions. Insulin seems to regulate the redox state of the organism and to determine the breakpoint of human breath-holding. This new hypoxia-insulin hypotheses might have major clinical relevance. Besides the clinical relevance, this hypothesis could explain, for the first time, why the training of the diaphragm, among other factors, results in an increase in breath-holding performance. Elite freedivers/apnea divers are able to reach static breath-holding times to over 6 min. Untrained persons exhibit an unpleasant feeling after more or less a minute. Breath-holding is stopped at the breakpoint. The partial oxygen pressure as well as the carbon dioxide pressure failed to directly influence the breakpoint in earlier studies. The factors that contribute to the breakpoint are still under debate. Under hypoxic conditions the organism needs more glucose, because it changes from the oxygen consuming pentose phosphate (36 ATP/glucose molecule) to the anaerobic glycolytic pathway (2ATP/glucose molecule). Hence insulin, as it promotes the absorption of glucose, is set in the center of interest regarding hypoxic conditions. This paper provides an insulin based model that could explain the changes and interactions in human breath-holding. The correlation between hypoxia and reactive oxygen species (ROS) and their influence on the sympathetic nerve system and hypoxia-inducible factor 1 alpha (HIF-1α) is dealt with. It reviews as well the direct interrelation of HIF-1α and insulin. The depression of insulin secretion through the vagus nerve activation via inspiration is discussed. Furthermore the paper describes the action of insulin on the carotid bodies and the diaphragm and therefore a possible role in respiration pattern. Freedivers that go over the breakpoint of breath-holding could exhibit seizures and thus the effect of

  2. Interactive effects of anthropogenic nitrogen enrichment and climate change on terrestrial and aquatic biodiversity

    EPA Science Inventory

    Climate change and Nr from anthropogenic activities are causing some of the most rapid changes in biodiversity in recent times. Climate change is causing warming trends that result in poleward and elevational range shiftsof flora and fauna, and changes in phenology, particularly ...

  3. Interactions between MAOA Genotype and Receipt of Public Assistance: Predicting Change in Depressive Symptoms and Body Mass Index

    ERIC Educational Resources Information Center

    Marmorstein, Naomi R.; Hart, Daniel

    2011-01-01

    Response to stress is determined in part by genetically influenced regulation of the monoamine system (MAOA). We examined the interaction of a stressor (receipt of public assistance) and a gene regulating MAOA in the prediction of change in adolescent depressive symptoms and body mass index (BMI). Participants were drawn from the National…

  4. Facilitation and inhibition: changes in plant nitrogen and secondary metabolites mediate interactions between aboveground and belowground herbivores

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To date, it remains unclear how herbivore-induced changes in plant primary and secondary metabolites impact aboveground and belowground herbivore interactions. Here we report the effects of aboveground (adult) and belowground (larval) feeding by Bikasha collaris on nitrogen and secondary chemicals i...

  5. Progressive and Regressive Developmental Changes in Neural Substrates for Face Processing: Testing Specific Predictions of the Interactive Specialization Account

    ERIC Educational Resources Information Center

    Joseph, Jane E.; Gathers, Ann D.; Bhatt, Ramesh S.

    2011-01-01

    Face processing undergoes a fairly protracted developmental time course but the neural underpinnings are not well understood. Prior fMRI studies have only examined progressive changes (i.e. increases in specialization in certain regions with age), which would be predicted by both the Interactive Specialization (IS) and maturational theories of…

  6. "It's Not a Political Issue!" The Interaction of Subject and Politics on Professors' Beliefs in Human-Induced Climate Change

    ERIC Educational Resources Information Center

    Nussbaum, E. Michael; Owens, Marissa C.; Cordova, Jacqueline R.

    2016-01-01

    This study examines the interaction of political orientation with academic discipline on beliefs in anthropogenic climate change (ACC) among higher education faculty. Over 300 faculty members at two research institutions in the United States were surveyed on topics concerning ACC and the results were analyzed with multiple regression. Even among…

  7. The Changes of Energy Interactions between Nucleus Function and Mitochondria Functions Causing Transmutation of Chronic Inflammation into Cancer Metabolism.

    PubMed

    Ponizovskiy, Michail R

    2016-01-01

    Interactions between nucleus and mitochondria functions induce the mechanism of maintenance stability of cellular internal energy according to the first law of thermodynamics in able-bodied cells and changes the mechanisms of maintenance stability of cellular internal energy creating a transition stationary state of ablebodied cells into quasi-stationary pathologic states of acute inflammation transiting then into chronic inflammation and then transmuting into cancer metabolism. The mechanisms' influences of intruding etiologic pathologic agents (microbe, virus, etc.) lead to these changes of energy interactions between nucleus and mitochondria functions causing general acute inflammation, then passing into local chronic inflammation, and reversing into cancer metabolism transmutation. Interactions between biochemical processes and biophysical processes of cellular capacitors' operations create a supplementary mechanism of maintenance stability of cellular internal energy in the norm and in pathology. Discussion of some scientific works eliminates doubts of the authors of these works. PMID:27480780

  8. Impacts of future changes in phenology on land-atmosphere interactions in temperate and boreal regions

    NASA Astrophysics Data System (ADS)

    Kaduk, Jörg; Los, Sietse

    2010-05-01

    ), which suggest an advance of more than six days average. The observed relationship between chilling and warming at the time of green-up indicates an element of regional adaptation of the warming required for leaf out in biomes covering large areas. The phenological models were implemented in the Joint UK Land Environment Simulator (JULES). In the model the advance in green up leads to a longer growing season with longer leaf display. In regions where soil moisture is mainly fed by spring rain and snow melt, however, there is only a limited increase of photosynthesis as it is determined by soil water availability. A longer summer dry period is resulting. Simulations including a Fire Weather Index indicate that the longer dry summers lead to an increase in the forest fire risk under future climate change in considerable areas. While this increase results partially from the changed climate, partially also the earlier leaf appearance contributes to the increased risk. Also there is a significant difference between simulations using only SWMs in contrast to employing also a chilling dependency. The results highlight the necessity of including appropriate phenology models in climate models for correct predictions of land-atmosphere interactions.

  9. The human health effects of ozone depletion and interactions with climate change.

    PubMed

    Norval, M; Lucas, R M; Cullen, A P; de Gruijl, F R; Longstreth, J; Takizawa, Y; van der Leun, J C

    2011-02-01

    for a range of internal cancers, this is not yet conclusive, but strongest for colorectal cancer, at present. A role for vitamin D in protection against several autoimmune diseases has been studied, with the most convincing results to date for multiple sclerosis. Vitamin D is starting to be assessed for its protective properties against several infectious and coronary diseases. Current methods for protecting the eye and the skin from the adverse effects of solar UV radiation are evaluated, including seeking shade, wearing protective clothing and sunglasses, and using sunscreens. Newer possibilities are considered such as creams that repair UV-induced DNA damage, and substances applied topically to the skin or eaten in the diet that protect against some of the detrimental effects of sun exposure. It is difficult to provide easily understandable public health messages regarding "safe" sun exposure, so that the positive effects of vitamin D production are balanced against the negative effects of excessive exposure. The international response to ozone depletion has included the development and deployment of replacement technologies and chemicals. To date, limited evidence suggests that substitutes for the ozone-depleting substances do not have significant effects on human health. In addition to stratospheric ozone depletion, climate change is predicted to affect human health, and potential interactions between these two parameters are considered. These include altering the risk of developing skin tumours, infectious diseases and various skin diseases, in addition to altering the efficiency by which pathogenic microorganisms are inactivated in the environment. PMID:21253670

  10. Aptitude-Treatment Interactions in Preservice Teachers' Behavior Change during Computer-Simulated Teaching

    ERIC Educational Resources Information Center

    Yeh, Yu-Chu

    2007-01-01

    Adapting training methods to specific teacher traits to best facilitate the training effects for preservice teachers is an important, yet neglected, topic in aptitude-treatment interaction research. This study investigated interactions between four personal traits (CT-dispositions, thinking styles, CT-skills, and intrapersonal intelligence) and…

  11. Changes in Traditional Television Content: Family Interaction Patterns on "The Simpsons."

    ERIC Educational Resources Information Center

    Larson, Mary Strom

    A study sought to describe family interaction as it has been taking place in a television family of the nineties--the Simpsons. Twelve episodes of the program were videotaped, transcriptions were made of the portions of the programs which contained family interactions, and 1,670 communication behaviors in the material were coded. Each behavior was…

  12. Stability and Change in Early Childhood Classroom Interactions during the First Two Hours of a Day

    ERIC Educational Resources Information Center

    Curby, Timothy W.; Grimm, Kevin J.; Pianta, Robert C.

    2010-01-01

    Early childhood classrooms support children's learning in a variety of ways. Of critical importance are the interactions teachers have with children. The type and quality of classroom interactions vary and can be grouped into three domains: instructional, organizational, and emotional. The purpose of this study is to examine the extent to which…

  13. Client-Treatment Interaction in the Study of Differential Change Processes.

    ERIC Educational Resources Information Center

    Shoham-Salomon, Varda; Hannah, Mo Therese

    1991-01-01

    Discusses epistemological and methodological issues regarding aptitude-treatment interactions (ATI) in psychotherapy. Noting that track record of interactional research is not very encouraging, argues that ATI research should focus on heuristic goal of illuminating mechanisms and processes that make therapies differentially effective. Suggests…

  14. Main and interactive effects of multiple global-change factors on soil respiration and its components: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Zhou, Xuhui

    2014-05-01

    Global change usually involves simultaneous changes in multiple environmental factors, which may considerably affect ecosystem structure and functioning and alter ecosystem services to human society. With increased awareness of their potential interactions, some multi-factorial studies have been conducted to investigate their main and interactive effects on carbon (C) cycling in terrestrial ecosystem. However, how multiple global-change factors affected soil respiration (Rs) and its components (i.e., autotrophic (Ra) and heterotrophic respiration (Rh)) remains controversial among individual studies. In this study, we conducted a meta-analysis to examine the main and possible 2- or 3-factor interactive effects with warming (W), elevated CO2 (E), nitrogen addition (N), increased precipitation (I) and drought (D) on Rs and its components from 150 published papers. Our results show that E, W, I and N significantly stimulated Rs by 29.23%, 7.19%, 22.95%, and 16.90% (p<0.05), respectively, while I depressed it by 16.90% (p<0.01). E consistently induced a significant positive effect on both Ra and Rh, while I affected them with an opposite trend. Among nine two-way interactive effects on Rs, synergistic interaction (i.e., the effect of combined treatment > the additive effects of single two main factors) occurred in E×N, E×W, I×N, and D×W, while neutral interaction (i.e., the effect of combined treatment ≡ the additive one) and antagonistic interaction (i.e., the effect of combined treatment < the additive one)was rare, only in I×W for neutral one and in N×W and I×E for the latter. In addition, E×W and E×N displayed synergistic interactions on Rh. The more dominance of synergistic interactions in two-way interactive effects on Rs and Rh may determine a central positive tendency of Rs in future, and affect the feedback of terrestrial C cycle to the climate system correspondingly.

  15. TERENO-SoilCan - Soil-Atmosphere Interactions Induced by Land Use Changes as a Result of Global Change

    NASA Astrophysics Data System (ADS)

    Puetz, T.; Burauel, P.; Bogena, H.; Vereecken, H.

    2009-04-01

    Based on the TERENO infrastructure, SoilCan (Soil can make a difference in climate policy) is designed as a long-term large scale experiment to study the effects of land use changes of terrestrial systems caused by Global Change. The soil and ground water, in particular the water and matter fluxes in soil, are the main focuses of SoilCan. Primary objectives of SoilCan are: • Further development of the instrumentation of the TERENO-observatories to study the effects of land use changes on soils • Collection of comprehensive long-term data to monitor Global Change on the regional scale • Provision of high-quality data to develop and improve the prognosis of regional climate models with the aim to develop and implement options for management strategies. In the frame of SoilCan, fully automated lysimeter systems will be installed on several highly equipped experimental field sites of the TERENO-observatories and the relevant status variables of each ecosystem will be monitored (e.g. climate, hydrology, biosphere-atmosphere exchange, biodiversity, etc.). The TERENO-observatories are placed in four different regions of Germany: • "Rur" observatory - moderate atlantic climate • "Ammer" observatory - alpine climate • "Bode" observatory - continental climate • "Müritz" observatory - baltic climate The field sites will have a radio-based technology for automatic monitoring and data communication. In total, 90 lysimeters (1.5 m depth, 1m2 surface) will be filled with soil monoliths at the four TERENO-observatories. The lysimeters will be partly transplanted along the existing natural temperature and rainfall gradients. The transplantation of lysimeters inside an observatory as well as between the four different observatories is of utmost importance for SoilCan. In case of the "Rur" observatory, three intensively instrumented field sites ("Wüstebach", "Rollesbroich" und "Selhausen") will be equipped with lysimeter stations. Along with a temperature and rainfall

  16. Large-scale changes in network interactions as a physiological signature of spatial neglect

    PubMed Central

    Baldassarre, Antonello; Ramsey, Lenny; Hacker, Carl L.; Callejas, Alicia; Astafiev, Serguei V.; Metcalf, Nicholas V.; Zinn, Kristi; Rengachary, Jennifer; Snyder, Abraham Z.; Carter, Alex R.; Shulman, Gordon L.

    2014-01-01

    networks in the right hemisphere; and (iii) increased intrahemispheric connectivity with the basal ganglia. These patterns of functional connectivity:behaviour correlations were stronger in patients with right- as compared to left-hemisphere damage and were independent of lesion volume. Our findings identify large-scale changes in resting state network interactions that are a physiological signature of spatial neglect and may relate to its right hemisphere lateralization. PMID:25367028

  17. Interactions of Changing Solar Ultraviolet Radiation and Climate with Light Induced Chemical Reactions in Aquatic Environments

    EPA Science Inventory

    Changes in the ozone layer over the past two decades have resulted in increases in solar ultraviolet radiation that reach the surface of North American aquatic environments. Concurrent changes in atmospheric CO2 are resulting in changes in stratification and precipitation that ar...

  18. Pax-3-DNA interaction: flexibility in the DNA binding and induction of DNA conformational changes by paired domains.

    PubMed Central

    Chalepakis, G; Wijnholds, J; Gruss, P

    1994-01-01

    The mouse Pax-3 gene encodes a protein that is a member of the Pax family of DNA binding proteins. Pax-3 contains two DNA binding domains: a paired domain (PD) and a paired type homeodomain (HD). Both domains are separated by 53 amino acids and interact synergistically with a sequence harboring an ATTA motif (binding to the HD) and a GTTCC site (binding to the PD) separated by 5 base pairs. Here we show that the interaction of Pax-3 with these two binding sites is independent of their angular orientation. In addition, the protein spacer region between the HD and the PD can be shortened without changing the spatial flexibility of the two DNA binding domains which interact with DNA. Furthermore, by using circular permutation analysis we determined that binding of Pax-3 to a DNA fragment containing a specific binding site causes conformational changes in the DNA, as indicated by the different mobilities of the Pax-3-DNA complexes. The ability to change the conformation of the DNA was found to be an intrinsic property of the Pax-3 PD and of all Pax proteins that we tested so far. These in vitro studies suggest that interaction of Pax proteins with their specific sequences in vivo may result in an altered DNA conformation. Images PMID:8065927

  19. Impacts of Ozone-vegetation Interactions and Biogeochemical Feedbacks on Atmospheric Composition and Air Quality Under Climate Change

    NASA Astrophysics Data System (ADS)

    Sadeke, M.; Tai, A. P. K.; Lombardozzi, D.; Val Martin, M.

    2015-12-01

    Surface ozone pollution is one of the major environmental concerns due to its damaging effects on human and vegetation. One of the largest uncertainties of future surface ozone prediction comes from its interaction with vegetation under a changing climate. Ozone can be modulated by vegetation through, e.g., biogenic emissions, dry deposition and transpiration. These processes are in turn affected by chronic exposure to ozone via lowered photosynthesis rate and stomatal conductance. Both ozone and vegetation growth are expected to be altered by climate change. To better understand these climate-ozone-vegetation interactions and possible feedbacks on ozone itself via vegetation, we implement an online ozone-vegetation scheme [Lombardozzi et al., 2015] into the Community Earth System Model (CESM) with active atmospheric chemistry, climate and land surface components. Previous overestimation of surface ozone in eastern US, Canada and Europe is shown to be reduced by >8 ppb, reflecting improved model-observation comparison. Simulated surface ozone is lower by 3.7 ppb on average globally. Such reductions (and improvements) in simulated ozone are caused mainly by lower isoprene emission arising from reduced leaf area index in response to chronic ozone exposure. Effects via transpiration are also potentially significant but require better characterization. Such findings suggest that ozone-vegetation interaction may substantially alter future ozone simulations, especially under changing climate and ambient CO2 levels, which would further modulate ozone-vegetation interactions. Inclusion of such interactions in Earth system models is thus necessary to give more realistic estimation and prediction of surface ozone. This is crucial for better policy formulation regarding air quality, land use and climate change mitigation. Reference list: Lombardozzi, D., et al. "The Influence of Chronic Ozone Exposure on Global Carbon and Water Cycles." Journal of Climate 28.1 (2015): 292-305.

  20. Short communication: Changes in fluorescence intensity induced by soybean soluble polysaccharide-milk protein interactions during acidification.

    PubMed

    Li, Y H; Wang, W J; Xu, X J; Meng, Y C; Zhang, L W; Chen, J; Qiu, R

    2015-12-01

    Interactions between stabilizer and milk protein are believed to influence the stabilizing behavior of the milk system. We investigated changes in fluorescence intensity induced by interactions of soybean soluble polysaccharide (SSPS) and milk protein (Mp) during acidification. The fluorescence intensity (If) of Mp increased as pH decreased from 6.8 to 5.2. Compared with Mp alone, If of SSPS-Mp mixtures increased as the pH decreased from 6.8 to 5.2. We found that the If of the SSPS-Mp mixture decreased in a pH range from 5.2 to 3.6, which indicated a change in the polarity microenvironment around the Trp residues. We also found that the maximum emission wavelength (λmax) shifted from 337 to 330nm as pH decreased from 6.8 to 3.6, in further support of SSPS interacting with the polar portion of Mp during acidification. Furthermore, an excited monomeric molecule (pyrene exciplex) was found as a ground-state pyrene formed and a broad band was shown at about 450nm. The intensity ratio of the first peak to the third peak (I1:I3) of Mp increased slightly, and the ratio of intensity of pyrene exciplex to monomer (Ie:Im) decreased because pyrene molecules were located in a less hydrophobic microenvironment during acidification. However, the ratio of I1:I3 decreased clearly at pH below 5.6 and the ratio of Ie:Im showed the opposite trend in the SSPS-Mp mixture. Changes in intrinsic and exogenous fluorescence intensity confirmed that interactions of SSPS and Mp could change the polarity of the microenvironment and that SSPS probably interacted with the polar portion of Mp. These results could give insight into the behavior of stabilizers in acid milk products. PMID:26476946

  1. Competition-interaction landscapes for the joint response of forests to climate change.

    PubMed

    Clark, James S; Bell, David M; Kwit, Matthew C; Zhu, Kai

    2014-06-01

    The recent global increase in forest mortality episodes could not have been predicted from current vegetation models that are calibrated to regional climate data. Physiological studies show that mortality results from interactions between climate and competition at the individual scale. Models of forest response to climate do not include interactions because they are hard to estimate and require long-term observations on individual trees obtained at frequent (annual) intervals. Interactions involve multiple tree responses that can only be quantified if these responses are estimated as a joint distribution. A new approach provides estimates of climate–competition interactions in two critical ways, (i) among individuals, as a joint distribution of responses to combinations of inputs, such as resources and climate, and (ii) within individuals, due to allocation requirements that control outputs, such as demographic rates. Application to 20 years of data from climate and competition gradients shows that interactions control forest responses, and their omission from models leads to inaccurate predictions. Species most vulnerable to increasing aridity are not those that show the largest growth response to precipitation, but rather depend on interactions with the local resource environment. This first assessment of regional species vulnerability that is based on the scale at which climate operates, individual trees competing for carbon and water, supports predictions of potential savannification in the southeastern US. PMID:24932467

  2. Delineating PAS-HAMP interaction surfaces and signalling-associated changes in the aerotaxis receptor Aer.

    PubMed

    Garcia, Darysbel; Watts, Kylie J; Johnson, Mark S; Taylor, Barry L

    2016-04-01

    The Escherichia coli aerotaxis receptor, Aer, monitors cellular oxygen and redox potential via FAD bound to a cytosolic PAS domain. Here, we show that Aer-PAS controls aerotaxis through direct, lateral interactions with a HAMP domain. This contrasts with most chemoreceptors where signals propagate along the protein backbone from an N-terminal sensor to HAMP. We mapped the interaction surfaces of the Aer PAS, HAMP and proximal signalling domains in the kinase-off state by probing the solvent accessibility of 129 cysteine substitutions. Inaccessible PAS-HAMP surfaces overlapped with a cluster of PAS kinase-on lesions and with cysteine substitutions that crosslinked the PAS β-scaffold to the HAMP AS-2 helix. A refined Aer PAS-HAMP interaction model is presented. Compared to the kinase-off state, the kinase-on state increased the accessibility of HAMP residues (apparently relaxing PAS-HAMP interactions), but decreased the accessibility of proximal signalling domain residues. These data are consistent with an alternating static-dynamic model in which oxidized Aer-PAS interacts directly with HAMP AS-2, enforcing a static HAMP domain that in turn promotes a dynamic proximal signalling domain, resulting in a kinase-off output. When PAS-FAD is reduced, PAS interaction with HAMP is relaxed and a dynamic HAMP and static proximal signalling domain convey a kinase-on output. PMID:26713609

  3. Three Connected Climate Education Interactives: Carbon Cycle, Earth System Energy Flows, and Climate Change Impacts/Adaptations

    NASA Astrophysics Data System (ADS)

    Sussman, A.

    2015-12-01

    The Pacific Islands Climate Education Partnership (PCEP) serves the U.S. Affiliated Pacific Island (USAPI) Region. The international entities served by PCEP are the state of Hawai'i (USA); three Freely Associated States (the Federated States of Micronesia, the Republic of the Marshall Islands, and the Republic of Palau), and three Territories (Guam, Commonwealth of Northern Mariana Islands, and American Samoa). Funded by NSF, the PCEP aims to educate the region's students and citizens in ways that exemplify modern science and indigenous environmental knowledge, address the urgency of climate change impacts, and focus on adaptation strategies that can increase resiliency with respect to climate change impacts. Unfortunately the vast majority of the science texts used in schools come from the US mainland and feature contexts that do not relate to the lives of Pacific island students. The curricular materials also tend to be older and to have very weak climate science content, especially with respect to tropical islands and climate change. In collaboration with public broadcast station WGBH, PCEP has developed three climate education interactives that sequentially provide an introduction to key climate change education concepts. The first in the series focuses on the global carbon cycle and connects increased atmospheric CO2 with rising global temperatures. The second analyzes Earth system energy flows to explain the key role of the increased greenhouse effect. The third focuses on four climate change impacts (higher temperatures, rising sea level, changes in precipitation, and ocean acidification), and adaptation strategies to increase resiliency of local ecosystems and human systems. While the interactives have a Pacific island visual and text perspective, they are broadly applicable for other education audiences. Learners can use the interactives to engage with the basic science concepts, and then apply the climate change impacts to their own contexts.

  4. Biophysical characterization of the structural change of Nopp140, an intrinsically disordered protein, in the interaction with CK2α.

    PubMed

    Na, Jung-Hyun; Lee, Won-Kyu; Kim, Yuyoung; Jeong, Cherlhyun; Song, Seung Soo; Cha, Sun-Shin; Han, Kyou-Hoon; Shin, Yeon-Kyun; Yu, Yeon Gyu

    2016-08-19

    Nucleolar phosphoprotein 140 (Nopp140) is a nucleolar protein, more than 80% of which is disordered. Previous studies have shown that the C-terminal region of Nopp140 (residues 568-596) interacts with protein kinase CK2α, and inhibits the catalytic activity of CK2. Although the region of Nopp140 responsible for the interaction with CK2α was identified, the structural features and the effect of this interaction on the structure of Nopp140 have not been defined due to the difficulty of structural characterization of disordered protein. In this study, the disordered feature of Nopp140 and the effect of CK2α on the structure of Nopp140 were examined using single-molecule fluorescence resonance energy transfer (smFRET) and electron paramagnetic resonance (EPR). The interaction with CK2α was increased conformational rigidity of the CK2α-interacting region of Nopp140 (Nopp140C), suggesting that the disordered and flexible conformation of Nopp140C became more rigid conformation as it binds to CK2α. In addition, site specific spin labeling and EPR analysis confirmed that the residues 574-589 of Nopp140 are critical for binding to CK2α. Similar technical approaches can be applied to analyze the conformational changes in other IDPs during their interactions with binding partners. PMID:27297113

  5. Impacts of elevated CO2, climate change and their interactions on water budgets in four different catchments in Australia

    NASA Astrophysics Data System (ADS)

    Cheng, Lei; Zhang, Lu; Wang, Ying-Ping; Yu, Qiang; Eamus, Derek; O'Grady, Anthony

    2014-11-01

    Future water availability is affected directly by climate change mainly through changes in precipitation and indirectly by the biological effects of climate change and elevated atmospheric CO2 concentration (eCO2) through changes in vegetation water use. Previous studies of climate change impact on hydrology have focused on the direct impact and little has been reported in the literature on catchment-scale the indirect impact. In this study, we calibrated an ecohydrological model (WAVES) and used this model to estimate the direct and indirect effects and the interactive effect between climate change and eCO2 on water availability in four different catchments in Australia with contrasting climate regime and vegetation cover. These catchments were: a water-limited forest catchment and an energy-limited forest catchment, a water-limited grass catchment and an energy-limited grass catchment. The future meteorological forcing was projected from 12 GCMs representing a period centred on 2050s and future CO2 concentration was set as 550 ppm. Modelling experiments show that impacts of eCO2 and projected climate change on vegetation growth, evapotranspiration (ET) and runoff were in the same magnitude but opposite directions in all four catchments, except for the effects on runoff in the energy-limited grass catchment. Predicted responses of runoff to eCO2 indicate that eCO2 increased runoff in the energy-limited forest catchment by ∼2% but decreased runoff in other three catchments from 1% to 18%. This study indicates that rising CO2 increases ecosystem water use efficiency but it does not necessarily result in increased runoff because elevated CO2 also stimulates vegetation growth and increases ET. Elevated CO2 was proved to have greater impacts on runoff than climate change in the forest catchments. Modelling experiments also suggest that interactive effects between climate and CO2 are important, especially for predicting leaf area index (LAI) and ET in grassland

  6. Is There a Temperate Bias in Our Understanding of How Climate Change Will Alter Plant-Herbivore Interactions? A Meta-analysis of Experimental Studies.

    PubMed

    Mundim, Fabiane M; Bruna, Emilio M

    2016-09-01

    Climate change can drive major shifts in community composition and interactions between resident species. However, the magnitude of these changes depends on the type of interactions and the biome in which they take place. We review the existing conceptual framework for how climate change will influence tropical plant-herbivore interactions and formalize a similar framework for the temperate zone. We then conduct the first biome-specific tests of how plant-herbivore interactions change in response to climate-driven changes in temperature, precipitation, ambient CO2, and ozone. We used quantitative meta-analysis to compare predicted and observed changes in experimental studies. Empirical studies were heavily biased toward temperate systems, so testing predicted changes in tropical plant-herbivore interactions was virtually impossible. Furthermore, most studies investigated the effects of CO2 with limited plant and herbivore species. Irrespective of location, most studies manipulated only one climate change factor despite the fact that different factors can act in synergy to alter responses of plants and herbivores. Finally, studies of belowground plant-herbivore interactions were also rare; those conducted suggest that climate change could have major effects on belowground subsystems. Our results suggest that there is a disconnection between the growing literature proposing how climate change will influence plant-herbivore interactions and the studies testing these predictions. General conclusions will also be hampered without better integration of above- and belowground systems, assessing the effects of multiple climate change factors simultaneously, and using greater diversity of species in experiments. PMID:27513912

  7. cNMA: a framework of encounter complex-based normal mode analysis to model conformational changes in protein interactions

    PubMed Central

    Oliwa, Tomasz; Shen, Yang

    2015-01-01

    Motivation: It remains both a fundamental and practical challenge to understand and anticipate motions and conformational changes of proteins during their associations. Conventional normal mode analysis (NMA) based on anisotropic network model (ANM) addresses the challenge by generating normal modes reflecting intrinsic flexibility of proteins, which follows a conformational selection model for protein–protein interactions. But earlier studies have also found cases where conformational selection alone could not adequately explain conformational changes and other models have been proposed. Moreover, there is a pressing demand of constructing a much reduced but still relevant subset of protein conformational space to improve computational efficiency and accuracy in protein docking, especially for the difficult cases with significant conformational changes. Method and results: With both conformational selection and induced fit models considered, we extend ANM to include concurrent but differentiated intra- and inter-molecular interactions and develop an encounter complex-based NMA (cNMA) framework. Theoretical analysis and empirical results over a large data set of significant conformational changes indicate that cNMA is capable of generating conformational vectors considerably better at approximating conformational changes with contributions from both intrinsic flexibility and inter-molecular interactions than conventional NMA only considering intrinsic flexibility does. The empirical results also indicate that a straightforward application of conventional NMA to an encounter complex often does not improve upon NMA for an individual protein under study and intra- and inter-molecular interactions need to be differentiated properly. Moreover, in addition to induced motions of a protein under study, the induced motions of its binding partner and the coupling between the two sets of protein motions present in a near-native encounter complex lead to the improved

  8. Salts employed in hydrophobic interaction chromatography can change protein structure - insights from protein-ligand interaction thermodynamics, circular dichroism spectroscopy and small angle X-ray scattering.

    PubMed

    Komaromy, Andras Z; Kulsing, Chadin; Boysen, Reinhard I; Hearn, Milton T W

    2015-03-01

    Key requirements of protein purification by hydrophobic interaction chromatography (HIC) are preservation of the tertiary/quaternary structure, maintenance of biological function, and separation of the correctly folded protein from its unfolded forms or aggregates. This study examines the relationship between the HIC retention behavior of hen egg white lysozyme (HEWL) in high concentrations of several kosmotropic salts and its conformation, assessed by circular dichroism (CD) spectroscopy. Further, the physicochemical properties of HEWL in the presence of high concentrations of ammonium sulfate, sodium chloride and magnesium chloride were investigated by small angle X-ray scattering (SAXS) at different temperatures. Radii of gyration were extrapolated from Guinier approximations and the indirect transform program GNOM with protein-protein interaction and contrast variation taken into account. A bead model simulation provided information on protein structural changes using ab initio reconstruction with GASBOR. These results correlated to the secondary structure content obtained from CD spectroscopy of HEWL. These changes in SAXS and CD data were consistent with heat capacity ΔCp -values obtained from van't Hoff plot analyses of the retention data. Collectively, these insights enable informed decisions to be made on the choice of chromatographic conditions, leading to improved separation selectivity and opportunities for innovative column-assisted protein refolding methods. PMID:25690783

  9. DEVELOPING TOOLS FOR EVALUATION OF INTERACTIONS BETWEEN GLOBAL CHANGE STRESSORS AND ECOSYSTEM FUNCTIONING

    EPA Science Inventory

    Case studies in key selected coral reefs and watersheds will be completed to provide scientific data, concepts and models that describe the responses of the functioning of these ecosystems to global change stressors. The studies will focus on relating global changes to local and...

  10. Applying Large-Group Interaction Methods in the Planning and Implementation of Major Change Efforts.

    ERIC Educational Resources Information Center

    Bryson, John M.; Anderson, Sharon R.

    2000-01-01

    Compares the assumptions, strengths, and weaknesses of seven approaches frequently used in the public sector to involve large numbers of people in planning and implementing change. The approaches are real-time strategic change, search conferences, future searches, strategic options development and analysis, strategic choice, technology of…

  11. The Effect of Unintended Interracial Contact Upon Racial Interaction and Attitude Change. Final Report.

    ERIC Educational Resources Information Center

    Cook, Stuart W.

    This was a study of the influence of unintended interracial contact and characteristics of the contact situation on attitude-related action and attitude change. It was designed to determine if persons with initially negative racial attitudes would change these attitudes by an experimental experience. The research subjects were white students from…

  12. CHARACTERIZE INTERACTIONS BETWEEN ECOSYSTEM FUNCTIONING AND CHANGES IN CLIMATE, UV, AND LAND USE

    EPA Science Inventory

    Assessments of the long-term impacts of global changes in climate, ultraviolet (UV) radiation and land use on ecosystems require scientific data, concepts and models that describe the responses of ecosystem health to stresses related to the changes as well as information and mode...

  13. Change over Time in Police Interactions and HIV Risk Behavior Among Female Sex Workers in Andhra Pradesh, India.

    PubMed

    Erausquin, Jennifer Toller; Reed, Elizabeth; Blankenship, Kim M

    2015-06-01

    Little is known about the effectiveness of intervening to change interactions between female sex workers (FSWs) and police in order to reduce HIV risk. Using data collected in the context of a HIV prevention intervention that included components to change policing practices (n = 1,680), we examine the association of FSWs' reports of negative police interactions and HIV risk behaviors and whether these associations varied over time. Results show negative police interactions declined significantly over time. FSWs who had more than one negative police interaction were more likely to experience STI symptoms (AOR 2.97 [95 % CI 2.27-3.89]), inconsistently use condoms with their clients (AOR 1.36 [95 % CI 1.03-1.79]), and accept more money for condomless sex (AOR 2.37 [95 % CI 1.76-3.21]). Over time, these associations were stable or increased. Even where interventions have reduced the number of police incidents experienced by FSWs, stakeholders in HIV prevention must remain vigilant in challenging these incidents. PMID:25354735

  14. Collaborative Education in Climate Change Sciences and Adaptation through Interactive Learning

    NASA Astrophysics Data System (ADS)

    Ozbay, G.; Sriharan, S.; Fan, C.

    2014-12-01

    As a result of several funded climate change education grants, collaboration between VSU, DSU, and MSU, was established to provide the innovative and cohesive education and research opportunities to underrepresented groups in the climate related sciences. Prior to offering climate change and adaptation related topics to the students, faculty members of the three collaborating institutions participated at a number of faculty training and preparation workshops for teaching climate change sciences (i.e. AMS Diversity Project Workshop, NCAR Faculty-Student Team on Climate Change, NASA-NICE Program). In order to enhance the teaching and student learning on various issues in the Environmental Sciences Programs, Climatology, Climate Change Sciences and Adaptation or related courses were developed at Delaware State University and its partner institutions (Virginia State University and Morgan State University). These courses were prepared to deliver information on physical basis for the earth's climate system and current climate change instruction modules by AMS and historic climate information (NOAA Climate Services, U.S. and World Weather Data, NCAR and NASA Climate Models). By using Global Seminar as a Model, faculty members worked in teams to engage students in videoconferencing on climate change through Contemporary Global Studies and climate courses including Climate Change and Adaptation Science, Sustainable Agriculture, Introduction to Environmental Sciences, Climatology, and Ecology and Adaptation courses. All climate change courses have extensive hands-on practices and research integrated into the student learning experiences. Some of these students have presented their classroom projects during Earth Day, Student Climate Change Symposium, Undergraduate Summer Symposium, and other national conferences.

  15. Feeling the heat: the effect of acute temperature changes on predator–prey interactions in coral reef fish

    PubMed Central

    Allan, Bridie J. M.; Domenici, Paolo; Munday, Phillip L.; McCormick, Mark I.

    2015-01-01

    Recent studies demonstrate that the elevated temperatures predicted to occur by the end of the century can affect the physiological performance and behaviour of larval and juvenile fishes; however, little is known of the effect of these temperatures on ecological processes, such as predator–prey interactions. Here, we show that exposure to elevated temperatures significantly affected the predator–prey interactions of a pair of common reef fish, the planktivorous damselfish (Pomacentrus wardi) and the piscivorous dottyback (Pseudochromis fuscus). When predators exposed to elevated temperatures interacted with prey exposed in a similar manner, maximal attack speeds increased. This effect coupled with decreasing prey escape speeds and escape distances led to increased predation rates. Prey exposed to elevated temperatures also had decreased reaction distances and increased apparent looming threshold, suggesting that their sensory performance was affected. This occurred despite the increase in maximal attack speeds, which in other species has been shown to increase reaction distances. These results suggest that the escape performance of prey is sensitive to short-term increases in ambient temperature. As marine environments become more thermally variable in the future, our results demonstrate that some predators may become more successful, suggesting that there will be strong selection for the maintenance of maximal escape performance in prey. In the present era of rapid climate change, understanding how changes to individual performance influence the relationships between predators and their prey will be increasingly important in predicting the effects of climate change within ecosystems. PMID:27293696

  16. Parental Behaviors during Family Interactions Predict Changes in Depression and Anxiety Symptoms during Adolescence

    ERIC Educational Resources Information Center

    Schwartz, Orli S.; Dudgeon, Paul; Sheeber, Lisa B.; Yap, Marie B. H.; Simmons, Julian G.; Allen, Nicholas B.

    2012-01-01

    This study investigated the prospective, longitudinal relations between parental behaviors observed during parent-adolescent interactions, and the development of depression and anxiety symptoms in a community-based sample of 194 adolescents. Positive and negative parental behaviors were examined, with negative behaviors operationalized to…

  17. Student Interests and Attitude Change toward Drug Educators as a Function of Sex and Role Interaction.

    ERIC Educational Resources Information Center

    Cotten-Huston, Annie L.

    1982-01-01

    Focused on recorded tapes and sex-role interaction of 12 sessions on drug abuse. Subjects were 247 seventh-grade males and females. Communicators (males and females) made two presentations with roles rotated according to ex-addict/learned specialist. Results indicated female and male students were influenced most by female specialist…

  18. Training Mildly Handicapped Peers to Facilitate Changes in the Social Interaction Skills of Autistic Children.

    ERIC Educational Resources Information Center

    Shafer, Michael S.; And Others

    1984-01-01

    A peer training strategy featuring direct prompting and modeling and involving 16 nonautistic peers (five-eight years old) resulted in immediate and substantial increases in peer trainers' interactions with their four autistic tutees. All four autistic Ss substantially increased their responsiveness to the peer trainers. (CL)

  19. Televised Models as Agents of Behavior Change: Inducing Pro-Social Interaction Among Severely Withdrawn Children.

    ERIC Educational Resources Information Center

    Kassier, Marjorie Rose

    The study examined the effectiveness of videotapes showing cooperative prosocial interaction between models on the behavior of 6 female and 14 male severely emotionally disturbed withdrawn children (aged between 9 and 14 years old). An introductory review of the literature considers general modeling theory, variables of the modeling act and their…

  20. Covering #SAE: A Mobile Reporting Class's Changing Patterns of Interaction on Twitter over Time

    ERIC Educational Resources Information Center

    Jones, Julie

    2015-01-01

    This study examined the social network that emerged on Twitter surrounding a mobile reporting class as they covered a national breaking news event. The work introduces pedagogical strategies that enhance students' learning opportunities. Through NodeXL and social network cluster analysis, six groups emerged from the Twitter interactions tied to…

  1. Changing learning with new interactive and media-rich instruction environments: virtual labs case study report.

    PubMed

    Huang, Camillan

    2003-01-01

    Technology has created a new dimension for visual teaching and learning with web-delivered interactive media. The Virtual Labs Project has embraced this technology with instructional design and evaluation methodologies behind the simPHYSIO suite of simulation-based, online interactive teaching modules in physiology for the Stanford students. In addition, simPHYSIO provides the convenience of anytime web-access and a modular structure that allows for personalization and customization of the learning material. This innovative tool provides a solid delivery and pedagogical backbone that can be applied to developing an interactive simulation-based training tool for the use and management of the Picture Archiving and Communication System (PACS) image information system. The disparity in the knowledge between health and IT professionals can be bridged by providing convenient modular teaching tools to fill the gaps in knowledge. An innovative teaching method in the whole PACS is deemed necessary for its successful implementation and operation since it has become widely distributed with many interfaces, components, and customizations. This paper will discuss the techniques for developing an interactive-based teaching tool, a case study of its implementation, and a perspective for applying this approach to an online PACS training tool. PMID:12620306

  2. Effects of Teacher-Child Interaction Training (TCIT) on Teacher Ratings of Behavior Change

    ERIC Educational Resources Information Center

    Garbacz, Lauren L.; Zychinski, Kristen E.; Feuer, Rachel M.; Carter, Jocelyn S.; Budd, Karen S.

    2014-01-01

    Problem behaviors in preschool-aged children negatively affect teacher-child relationships and children's skill development. In this clinical replication of an initial study, we implemented Teacher-Child Interaction Training (TCIT), a teacher-delivered, universal intervention designed for early childhood settings. The initial study evaluated…

  3. Developmental Changes of Expressive Language and Interactive Competences in Children with Autism

    ERIC Educational Resources Information Center

    Pry, R.; Petersen, A. F.; Baghdadli, A.

    2009-01-01

    It is well established that language development in children with autism is disturbed in a number of ways, and evidence is accumulating that their emerging linguistic skills may be related to interactive competences such as joint attention, imitation and certain aspects of play as has been found in normally developing children. The present study…

  4. Changing Classroom Practice through the English National Literacy Strategy: A Micro-Interactional Perspective

    ERIC Educational Resources Information Center

    Lefstein, Adam

    2008-01-01

    How and why is national policy translated into interactions between teachers and pupils? This article examines the enactment of the English National Literacy Strategy (NLS) in a case study of two literacy lessons, which are drawn from a yearlong ethnographic study of the NLS in one school. Although the teacher taught directly from and adhered…

  5. Effects of stratospheric ozone depletion, solar UV radiation, and climate change on biogeochemical cycling: interactions and feedbacks

    SciTech Connect

    Erickson III, David J.; Sulzberger, Barbara; Zepp, Richard G.; Austin, Amy T.

    2014-11-07

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment include: (i) enhanced UV-induced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced mineralisation of photoreactive dissolved organic matter (DOM) in aquatic ecosystems due to changes in continental runoff and ice melting; (iii) reduced efficiency of the biological pump due to UV-induced bleaching of coloured dissolved organic matter (CDOM) in stratified aquatic ecosystems, where CDOM protects phytoplankton from the damaging solar UV-B radiation. Mineralisation of organic matter results in the production and release of CO2, whereas the biological pump is the main biological process for CO2 removal by aquatic ecosystems. This research also assesses the interactive effects of solar UV radiation and climate change on the biogeochemical cycling of aerosols and trace gases other than CO2, as well as of chemical and biological contaminants. Lastly,, interacting effects of solar UV radiation and climate change on biogeochemical cycles are particularly pronounced at terrestrial-aquatic interfaces.

  6. Effects of stratospheric ozone depletion, solar UV radiation, and climate change on biogeochemical cycling: interactions and feedbacks

    DOE PAGESBeta

    Erickson III, David J.; Sulzberger, Barbara; Zepp, Richard G.; Austin, Amy T.

    2014-11-07

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment include: (i) enhanced UV-induced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced mineralisation of photoreactive dissolved organic matter (DOM) in aquatic ecosystems due to changes in continental runoff and ice melting; (iii) reduced efficiency of the biological pump due to UV-induced bleaching of coloured dissolved organic matter (CDOM) in stratified aquatic ecosystems, where CDOM protects phytoplankton from the damaging solarmore » UV-B radiation. Mineralisation of organic matter results in the production and release of CO2, whereas the biological pump is the main biological process for CO2 removal by aquatic ecosystems. This research also assesses the interactive effects of solar UV radiation and climate change on the biogeochemical cycling of aerosols and trace gases other than CO2, as well as of chemical and biological contaminants. Lastly,, interacting effects of solar UV radiation and climate change on biogeochemical cycles are particularly pronounced at terrestrial-aquatic interfaces.« less

  7. Effects of stratospheric ozone depletion, solar UV radiation, and climate change on biogeochemical cycling: interactions and feedbacks.

    PubMed

    Erickson, David J; Sulzberger, Barbara; Zepp, Richard G; Austin, Amy T

    2015-01-01

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment include: (i) enhanced UV-induced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced mineralisation of photoreactive dissolved organic matter (DOM) in aquatic ecosystems due to changes in continental runoff and ice melting; (iii) reduced efficiency of the biological pump due to UV-induced bleaching of coloured dissolved organic matter (CDOM) in stratified aquatic ecosystems, where CDOM protects phytoplankton from the damaging solar UV-B radiation. Mineralisation of organic matter results in the production and release of CO2, whereas the biological pump is the main biological process for CO2 removal by aquatic ecosystems. This paper also assesses the interactive effects of solar UV radiation and climate change on the biogeochemical cycling of aerosols and trace gases other than CO2, as well as of chemical and biological contaminants. Interacting effects of solar UV radiation and climate change on biogeochemical cycles are particularly pronounced at terrestrial-aquatic interfaces. PMID:25380348

  8. Extracellular matrix-associated proteome changes during non-host resistance in citrus-Xanthomonas interactions.

    PubMed

    Swaroopa Rani, Tirupaati; Podile, Appa Rao

    2014-04-01

    Non-host resistance (NHR) is a most durable broad-spectrum resistance employed by the plants to restrict majority of pathogens. Plant extracellular matrix (ECM) is a critical defense barrier. Understanding ECM responses during interaction with non-host pathogen will provide insights into molecular events of NHR. In this study, the ECM-associated proteome was compared during interaction of citrus with pathogen Xanthomonas axonopodis pv. citri (Xac) and non-host pathogen Xanthomonas oryzae pv. oryzae (Xoo) at 8, 16, 24 and 48 h post inoculation. Comprehensive analysis of ECM-associated proteins was performed by extracting wall-bound and soluble ECM components using both destructive and non-destructive procedures. A total of 53 proteins was differentially expressed in citrus-Xanthomonas host and non-host interaction, out of which 44 were identified by mass spectrometry. The differentially expressed proteins were related to (1) defense-response (5 pathogenesis-related proteins, 3 miraculin-like proteins (MIR, MIR1 and MIR2) and 2 proteases); (2) enzymes of reactive oxygen species (ROS) metabolism [Cu/Zn superoxide dismutase (SOD), Fe-SOD, ascorbate peroxidase and 2-cysteine-peroxiredoxin]; (3) signaling (lectin, curculin-like lectin and concanavalin A-like lectin kinase); and (4) cell-wall modification (α-xylosidase, glucan 1, 3 β-glucosidase, xyloglucan endotransglucosylase/hydrolase). The decrease in ascorbate peroxidase and cysteine-peroxiredoxin could be involved in maintenance of ROS levels. Increase in defense, cell-wall remodeling and signaling proteins in citrus-Xoo interaction suggests an active involvement of ECM in execution of NHR. Partially compromised NHR in citrus against Xoo, upon Brefeldin A pre-treatment supported the role of non-classical secretory proteins in this phenomenon. PMID:24117905

  9. Changing restoration rules: exotic bivalves interact with residence time and depth to control phytoplankton productivity

    USGS Publications Warehouse

    Lucas, Lisa V.; Thompson, Janet K.

    2012-01-01

    Non-native species are a prevalent ecosystem stressor that can interact with other stressors to confound resource management and restoration. We examine how interactions between physical habitat attributes and a particular category of non-native species (invasive bivalves) influence primary production in aquatic ecosystems. Using mathematical models, we show how intuitive relationships between phytoplankton productivity and controllable physical factors (water depth, hydraulic transport time) that hold in the absence of bivalves can be complicated—and even reversed—by rapid bivalve grazing. In light-limited environments without bivalves, shallow, hydrodynamically “slow” habitats should generally have greater phytoplankton biomass and productivity than deeper, “faster” habitats. But shallower, slower environments can be less productive than deeper, faster ones if benthic grazing is strong. Moreover, shallower and slower waters exhibit a particularly broad range of possible productivity outcomes that can depend on whether bivalves are present. Since it is difficult to predict the response of non-native bivalves to habitat restoration, outcomes for new shallow, slow environments can be highly uncertain. Habitat depth and transport time should therefore not be used as indicators of phytoplankton biomass and production where bivalve colonization is possible. This study provides for ecosystem management a particular example of a broad lesson: abiotic ecosystem stressors should be managed with explicit consideration of interactions with other major (including biotic) stressors. We discuss the applicability and management implications of our models and results for a range of aquatic system types, with a case study focused on the Sacramento-San Joaquin Delta (California, USA). Simple mathematical models like those used here can illuminate interactions between ecosystem stressors and provide process-based guidance for resource managers as they develop strategies

  10. Morphological and physiological changes induced by contact-dependent interaction between Candida albicans and Fusobacterium nucleatum.

    PubMed

    Bor, Batbileg; Cen, Lujia; Agnello, Melissa; Shi, Wenyuan; He, Xuesong

    2016-01-01

    Candida albicans and Fusobacterium nucleatum are well-studied oral commensal microbes with pathogenic potential that are involved in various oral polymicrobial infectious diseases. Recently, we demonstrated that F. nucleatum ATCC 23726 coaggregates with C. albicans SN152, a process mainly mediated by fusobacterial membrane protein RadD and Candida cell wall protein Flo9. The aim of this study was to investigate the potential biological impact of this inter-kingdom interaction. We found that F. nucleatum ATCC 23726 inhibits growth and hyphal morphogenesis of C. albicans SN152 in a contact-dependent manner. Further analysis revealed that the inhibition of Candida hyphal morphogenesis is mediated via RadD and Flo9 protein pair. Using a murine macrophage cell line, we showed that the F. nucleatum-induced inhibition of Candida hyphal morphogenesis promotes C. albicans survival and negatively impacts the macrophage-killing capability of C. albicans. Furthermore, the yeast form of C. albicans repressed F. nucleatum-induced MCP-1 and TNFα production in macrophages. Our study suggests that the interaction between C. albicans and F. nucleatum leads to a mutual attenuation of virulence, which may function to promote a long-term commensal lifestyle within the oral cavity. This finding has significant implications for our understanding of inter-kingdom interaction and may impact clinical treatment strategies. PMID:27295972

  11. Morphological and physiological changes induced by contact-dependent interaction between Candida albicans and Fusobacterium nucleatum

    PubMed Central

    Bor, Batbileg; Cen, Lujia; Agnello, Melissa; Shi, Wenyuan; He, Xuesong

    2016-01-01

    Candida albicans and Fusobacterium nucleatum are well-studied oral commensal microbes with pathogenic potential that are involved in various oral polymicrobial infectious diseases. Recently, we demonstrated that F. nucleatum ATCC 23726 coaggregates with C. albicans SN152, a process mainly mediated by fusobacterial membrane protein RadD and Candida cell wall protein Flo9. The aim of this study was to investigate the potential biological impact of this inter-kingdom interaction. We found that F. nucleatum ATCC 23726 inhibits growth and hyphal morphogenesis of C. albicans SN152 in a contact-dependent manner. Further analysis revealed that the inhibition of Candida hyphal morphogenesis is mediated via RadD and Flo9 protein pair. Using a murine macrophage cell line, we showed that the F. nucleatum-induced inhibition of Candida hyphal morphogenesis promotes C. albicans survival and negatively impacts the macrophage-killing capability of C. albicans. Furthermore, the yeast form of C. albicans repressed F. nucleatum-induced MCP-1 and TNFα production in macrophages. Our study suggests that the interaction between C. albicans and F. nucleatum leads to a mutual attenuation of virulence, which may function to promote a long-term commensal lifestyle within the oral cavity. This finding has significant implications for our understanding of inter-kingdom interaction and may impact clinical treatment strategies. PMID:27295972

  12. Interactive Puzzles for the mean climate dyanmics and climate change with the Monash Simple Climate Model

    NASA Astrophysics Data System (ADS)

    Dommenget, D.

    2014-12-01

    The Monash university interactive simple climate model is a web-based interface that allows students and the general public to explore the physical simulation of the climate system with a real global climate model. It is based on the Globally Resolved Energy Balance (GREB) model that simulates most of the main physical processes in the climate system in a very simplistic way and therefore allows very fast and simple climate model simulations. Despite its simplicity the model simulates the mean climate and its response to external forcings, such as doubling of the CO2 concentrations very realistically.The Monash simple climate model web-interface allows you to do some entertaining and educational puzzles about the interaction of climate dynamics. By turning switches OFF and ON you control physical processes in the climate system, but you do not know what these processes. By testing a number of experiments you learn about the interactions in the climate system and thereby figure out which switch controls what process in the climate system. The presentation will illustrate how this web-base tool works and what are the possibilities in teaching students with this tool are.

  13. Early developmental changes in the timing of turn-taking: a longitudinal study of mother–infant interaction

    PubMed Central

    Hilbrink, Elma E.; Gattis, Merideth; Levinson, Stephen C.

    2015-01-01

    To accomplish a smooth transition in conversation from one speaker to the next, a tight coordination of interaction between speakers is required. Recent studies of adult conversation suggest that this close timing of interaction may well be a universal feature of conversation. In the present paper, we set out to assess the development of this close timing of turns in infancy in vocal exchanges between mothers and infants. Previous research has demonstrated an early sensitivity to timing in interactions (e.g., Murray and Trevarthen, 1985). In contrast, less is known about infants’ abilities to produce turns in a timely manner and existing findings are rather patchy. We conducted a longitudinal study of 12 mother–infant dyads in free-play interactions at the ages of 3, 4, 5, 9, 12, and 18 months. Based on existing work and the predictions made by the Interaction Engine Hypothesis (Levinson, 2006), we expected that infants would begin to develop the temporal properties of turn-taking early in infancy but that their timing of turns would slow down at 12 months, which is around the time when infants start to produce their first words. Findings were consistent with our predictions: infants were relatively fast at timing their turn early in infancy but slowed down toward the end of the first year. Furthermore, the changes observed in infants’ turn-timing skills were not caused by changes in maternal timing, which remained stable across the 3–18 months period. However, the slowing down of turn-timing started somewhat earlier than predicted: at 9 months. PMID:26483741

  14. Early developmental changes in the timing of turn-taking: a longitudinal study of mother-infant interaction.

    PubMed

    Hilbrink, Elma E; Gattis, Merideth; Levinson, Stephen C

    2015-01-01

    To accomplish a smooth transition in conversation from one speaker to the next, a tight coordination of interaction between speakers is required. Recent studies of adult conversation suggest that this close timing of interaction may well be a universal feature of conversation. In the present paper, we set out to assess the development of this close timing of turns in infancy in vocal exchanges between mothers and infants. Previous research has demonstrated an early sensitivity to timing in interactions (e.g., Murray and Trevarthen, 1985). In contrast, less is known about infants' abilities to produce turns in a timely manner and existing findings are rather patchy. We conducted a longitudinal study of 12 mother-infant dyads in free-play interactions at the ages of 3, 4, 5, 9, 12, and 18 months. Based on existing work and the predictions made by the Interaction Engine Hypothesis (Levinson, 2006), we expected that infants would begin to develop the temporal properties of turn-taking early in infancy but that their timing of turns would slow down at 12 months, which is around the time when infants start to produce their first words. Findings were consistent with our predictions: infants were relatively fast at timing their turn early in infancy but slowed down toward the end of the first year. Furthermore, the changes observed in infants' turn-timing skills were not caused by changes in maternal timing, which remained stable across the 3-18 months period. However, the slowing down of turn-timing started somewhat earlier than predicted: at 9 months. PMID:26483741

  15. Changing Misconceptions in Newton's Laws of Motion Through Playing Computer Games and Peer Interaction

    NASA Astrophysics Data System (ADS)

    Back, Hyejoo

    This study was conducted to acquire information about students' misconceptions on Newton's laws of motion. Three major hypotheses were examined: (1) students' performance on the posttest after playing the games set in the context of a Newtonian microworld will be significantly better than their performance on the pretest; (2) performance of the students playing the games in a peer cooperative learning setting will improve significantly better than the students who play the games individually; (3) there will be a differential relationship between students with different abilities' performance on the posttest and student interactions in a cooperative learning setting measured by verbal interaction variables. Fifty-three subjects were drawn from 12th grade physics classes at two high schools located in a suburban area of the State of Connecticut. All the students had studied vector addition, Newton's laws of motion, and conservation of momentum. To test the hypotheses, some students played the computer games in a cooperative learning setting and others in an individual learning setting. A series of force and motion problems (White, 1981, 1983) was used as a pretest and a posttest. The nature of verbal interactions in the peer cooperative learning setting was also examined to find the relationship between interaction variables and achievement on the posttest. Comparisons of results were also made with the results of White's study (1981) in which the same dynamics problems were used as a pretest and a posttest. The results show that the students who played computer games in both learning settings performed better on the posttest than on the pretest. On the difference between the performance improvement of the students in two learning settings, the students of all three levels in a peer cooperative learning setting improved more than the students of each corresponding level in individual learning setting. An analysis of videotapes of student verbal interactions in the

  16. Contributions of soil moisture interactions to climate change in the tropics in the GLACE-CMIP5 experiment

    NASA Astrophysics Data System (ADS)

    May, Wilhelm; Meier, Arndt; Rummukainen, Markku; Berg, Alexis; Chéruy, Frederique; Hagemann, Stefan

    2015-12-01

    Contributions of changes in soil moisture to the projected climate change in the tropics at the end of the twenty first century are quantified using the simulations from five different global climate models, which contributed to the GLACE-CMIP5 experiment. "GLACE" refers to the Global Land Atmosphere Coupling Experiment and "CMIP5" to the fifth phase of the Coupled Model Intercomparison Project. This is done by relating the overall projected changes in climate to those changes in climate that are related to the projected changes in soil moisture. The study focusses on two particular aspects of the interactions of the soil moisture with climate, the soil moisture-temperature coupling and the soil moisture-precipitation coupling. The simulations show distinct future changes in soil moisture content in the tropics, with a general tendency of increases in the central parts of the tropics and decreases in the subtropics. These changes are associated with corresponding changes in precipitation, with an overall tendency of an approximate 5 % change in soil moisture in response to a precipitation change of 1 mm/day. All five individual models are characterized by the same qualitative behaviour, despite differences in the strength and in the robustness of the coupling between soil moisture and precipitation. The changes in soil moisture content are found to give important contributions to the overall climate change in the tropics. This is in particularly the case for latent and sensible heat flux, for which about 80 % of the overall changes are related to soil moisture changes. Similarly, about 80 % of the overall near-surface temperature changes (with the mean temperature changes in the tropics removed) are associated with soil moisture changes. For precipitation, on the other hand, about 30-40 % of the overall change can be attributed to soil moisture changes. The robustness of the contributions of the soil moisture changes to the overall climate change varies between the

  17. Climate change: potential impacts and interactions in wetlands of the United States

    USGS Publications Warehouse

    Burkett, V.R.; Kusler, J.

    2000-01-01

    Wetlands exist in a transition zone between aquatic and terrestrial environments which can be altered by subtle changes in hydrology. Twentieth century climate records show that the United States is generally experiencing a trend towards a wetter, warmer climate; some climate models suggest that his trend will continue and possibly intensify over the next 100 years. Wetlands that are most likely to be affected by these and other potential changes (e.g., sea-level rise) associated with atmospheric carbon enrichment include permafrost wetlands, coastal and estuarine wetlands, peatlands, alpine wetlands, and prairie pothote wetlands. Potential impacts range from changes in community structure to changes in ecological function, and from extirpation to enhancement. Wetlands (particularly boreal peatlands) play an important role in the global carbon cycle, generally sequestering carbon in the form of biomass, methane, dissolved organic material and organic sediment. Wetlands that are drained or partially dried can become a net source of methane and carbon dioxide to the atmosphere, serving as a positive biotic feedback to global warming. Policy options for minimizing the adverse impacts of climate change on wetland ecosystems include the reduction of current anthropogenic stresses, allowing for inland migration of coastal wetlands as sea-level rises, active management to preserve wetland hydrology, and a wide range of other management and restoration options.

  18. Phenology of species interactions in response to climate change: two case studies of plant-pollinator interactions using long-term data

    NASA Astrophysics Data System (ADS)

    McKinney, A. M.; Inouye, D. W.

    2012-12-01

    Climate change may alter the temporal overlap among interacting taxa with potential demographic consequences. Evidence of mistimed interactions in response to climate change, especially between plants and pollinators, is mixed, and few long-term datasets exist to test for changes in synchrony. Furthermore, advancements in flowering driven by climate change are especially pronounced at higher latitudes, so that migratory pollinators from lower latitudes may increasingly arrive at breeding grounds after the appearance of floral resources. We explored long-term shifts in phenological synchrony in two plant-pollinator systems:1) syrphid fly and flowering phenology in the Colorado Rocky Mountains, USA (1992-2011) and 2) hummingbird arrival relative to onset of early-season nectar resources in the Colorado Rocky Mountains (1975-2011) and the Santa Catalina Mountains, Arizona, USA (1984-2010). We investigated the abiotic cues associated with the phenology of the activity period of syrphid flies and their floral resources, including degree days above freezing, precipitation, and timing of snowmelt as potential explanatory variables. Timing of snowmelt was the best predictor of the onset of flowering and syrphid emergence. Snowmelt was also the best predictor of the end of flowering, while temperature and precipitation best predicted the end of the syrphid period. Both the onset and end of flowering advanced more rapidly than syrphids in response to earlier snowmelt. These different rates of phenological advancement resulted in increased temporal overlap between the flower and syrphid community in years of early snowmelt, because of longer flowering and fly activity periods during these years. If snowmelt continues to advance, temporal overlap between syrphids and their floral resources is therefore likely to increase. This case study shows that the phenology of interacting taxa may respond differently to climate cues, but that this does not necessarily lead to phenological

  19. NASA's "Images of Change" App and the Power of Interactive Visuals

    NASA Astrophysics Data System (ADS)

    Kasprak, A. H.; Mansfield, K. J.; Novati, A.; Leon, N.; Jackson, R.; Greene, M.

    2014-12-01

    The old cliché of a picture being worth a thousand words couldn't be more apt when it comes to conveying the reality of natural and anthropogenic environmental change. Here, we present a NASA mobile app (iOS) that makes use of visuals to deliver a powerful message capable of resonating with young and old alike. The app—Images of Change—presents a curated collection of the best image pairs from NASA's Global Climate Change website. These image pairs show areas that have been subject to natural disasters or seen significant change over time. All photo pairs can be viewed individually, side by side, or overlaid with a slider bar for easy comparisons. The photos are meticulously selected and regularly updated to give you an informative, compelling, and up-to-date visual experience.

  20. Widespread habitat change through paludification as an interactive mechanism in mass extinction events

    NASA Technical Reports Server (NTRS)

    Klinger, L. F.

    1988-01-01

    The study of mass extinction events has largely focused on defining an environmental factor or factors that might account for specific patterns of faunal demise. Several hypotheses elaborate on how a given environmental factor might affect fauna directly, but differentially, causing extinction in certain taxa but not others. Yet few studies have considered specific habitat changes that might result from natural vegetation processes or from perturbations of vegetation. The role of large-scale habitat change induced by natural successional change from forest to bog (paludification) is examined and how large perturbations (e.g., volcanism, bolide impacts) might favor increased rates of paludification and consequent mass extinctions is considered. This hypothesis has an advantage over other hypotheses for mass extinctions in that modern day analogs of paludification are common throughout the world, thus allowing for considerable testing.

  1. Lake-river and lake-atmosphere interactions in a changing climate over Northeast Canada

    NASA Astrophysics Data System (ADS)

    Huziy, Oleksandr; Sushama, Laxmi

    2016-04-01

    Lakes influence the regional climate and hydrology in a number of ways and therefore they should be represented in climate models in a realistic manner. Lack of representation of lakes in models can lead to errors in simulated energy and water fluxes, for lake-rich regions. This study focuses on the assessment of the impact of climate change on lakes and hydrology as well as on the influence of lakes on projected changes to regional climate and surface hydrology, particularly streamflows, for Northeast Canada. To this end, transient climate change simulations spanning the 1950-2100 period are performed, with and without lakes, with the fifth generation of the Canadian Regional Climate Model (CRCM5), driven by the Canadian Earth System Model (CanESM2) at the lateral boundaries for Representative Concentration Pathway 8.5. Comparison of projected changes from the CRCM5 simulations with and without lakes suggest that lakes attenuate projected increases to 2-m air temperature in all seasons, almost everywhere in the study domain, with maximum decreases of the order of 2°C occurring during winter. As for streamflows, results suggest projected increases for winter and spring and decreases during summer. Comparison of the projected changes suggests that lakes attenuate the projected increases in streamflows in spring due to the storage effect of lakes, and also attenuate the projected decreases in streamflows in summer in future climate due to the gradual release of the excess water stored in the lakes during spring. This study, thus demonstrates the impact of lakes on projected changes to the regional climate and hydrology for the study region using a single regional modelling system.

  2. CTFS/ForestGEO: A global network to monitor forest interactions with a changing climate

    NASA Astrophysics Data System (ADS)

    Anderson-Teixeira, K. J.; Muller-Landau, H.; McMahon, S.; Davies, S. J.

    2013-12-01

    Forests are an influential component of the global carbon cycle and strongly influence Earth's climate. Climate change is altering the dynamics of forests globally, which may result in significant climate feedbacks. Forest responses to climate change entail both short-term ecophysiological responses and longer-term directional shifts in community composition. These short- and long-term responses of forest communities to climate change may be better understood through long-term monitoring of large forest plots globally using standardized methodology. Here, we describe a global network of forest research plots (CTFS/ForestGEO) of utility for understanding forest responses to climate change and consequent feedbacks to the climate system. CTFS/ForestGEO is an international network consisting of 51 sites ranging in size from 2-150 ha (median size: 25 ha) and spanning from 25°S to 52°N latitude. At each site, every individual > 1cm DBH is mapped and identified, and recruitment, growth, and mortality are monitored every 5 years. Additional measurements include aboveground productivity, carbon stocks, soil nutrients, plant functional traits, arthropod and vertebrates monitoring, DNA barcoding, airborne and ground-based LiDAR, micrometeorology, and weather monitoring. Data from this network are useful for understanding how forest ecosystem structure and function respond to spatial and temporal variation in abiotic drivers, parameterizing and evaluating ecosystem and earth system models, aligning airborne and ground-based measurements, and identifying directional changes in forest productivity and composition. For instance, CTFS/ForestGEO data have revealed that solar radiation and night-time temperature are important drivers of aboveground productivity in moist tropical forests; that tropical forests are mixed in terms of productivity and biomass trends over the past couple decades; and that the composition of Panamanian forests has shifted towards more drought

  3. Vegetation change on a northeast tidal marsh: Interaction of sea-level rise and marsh accretion

    SciTech Connect

    Warren, R.S.; Niering, W.A. )

    1993-01-01

    Increasing rates of relative sea-level rise (RSL) have been linked to coastal wetland losses along the Gulf of Mexico and elsewhere. Rapidly rising RSL may be affecting New England tidal marshes. Studies of the Wequetequock-Pawcatuck tidal marshes over four decades have documented dramatic changes in vegetation apparently related primarily to differential rates of marsh accretion and sea-level rise though sediment supply and anthropogenic modifications of the system may also be involved. When initially studied in 1947-1948 the high marsh supported a Juncus gerardi-Spartina patens belting pattern typical of many New England salt marshes. On most of the marsh complex the former Juncus belt has now been replaced by forbs, primarily Triglochin maritima, while the former S. patens high marsh is now a complex of vegetation types-stunted Spartina alterniflora, Distichlis spicata, forbs, and relic stands of S. patens. The mean surface elevation of areas where the vegetation has changed is significantly lower than that of areas still supporting the earlier pattern (4.6 vs. 13.9 cm above mean tide level). The differences in surface elevation reflect differences in accretion of marsh peat. Stable areas have been accreting at the rate of local sea-level rise, 2.0-2.5 mm/yr at least since 1938; changed areas have accreted at about one half that rate. Lower surface elevations result in greater frequency and duration of tidal flooding, and thus in increased peat saturation, salinity, and sulfide concentrations, and in decreased redox potential, as directly measured over the growing season at both changed and stable sites. These edaphic changes may have combined to favor establishment of a wetter, more open vegetation type. Similar changes have been observed on other Long Island Sound marshes and may be a model for the potential effects of sea-level rise on New England tidal salt marshes. 39 refs., 4 figs., 1 tab.

  4. Size-related change in Nitraria sphaerocarpa patches shifts the shrub-annual interaction in an arid desert, northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, Gefei; Yang, Qiyue; Wang, Xiaofen; Zhao, Wenzhi

    2015-11-01

    In arid and semi-arid ecosystems, the effect of shrubs on their understory plants has been frequently reported. Many previous studies have shown that both facilitation and competition act simultaneously, and their balance changes in response to spatial or temporal variations in environmental stresses. Yet, we know little about how the interaction varies between shrubs and their understory plants in vegetation patches with different characteristics. Here, an empirical investigation was conducted in Hexi desert region of northwest China, to evaluate how the net effect of Nitraria sphaerocarpa shrubs on the herbaceous species varies across different sizes of N. sphaerocarpa patches. Our study showed that herbaceous species perform better on small shrub patches. But the magnitude of this facilitative effect decreased with increasing patch size, and finally shifted to interference in large patches. The results indicated that these negative shifts in plant interactions were not clearly related to 'shrub-island effect' in terms of nutrient accumulation or soil properties improvement, but may be explained by the variation in other abiotic factors, such as soil moisture and available light. Changes in root distribution and canopy structure of N. sphaerocarpa shrubs with the increase of patch size seem to also partly explain the variation in shrub-understory species interactions, as a result of increased above- and below-ground niche overlaps.

  5. Lake-river and lake-atmosphere interactions in a changing climate over Northeast Canada

    NASA Astrophysics Data System (ADS)

    Huziy, O.; Sushama, L.

    2016-07-01

    Lakes influence the regional climate and hydrology in a number of ways and therefore they should be represented in climate models in a realistic manner. Lack of representation of lakes in models can lead to errors in simulated energy and water fluxes, for lake-rich regions. This study focuses on the assessment of the impact of climate change on lakes and hydrology as well as on the influence of lakes on projected changes to regional climate and surface hydrology, particularly streamflows, for Northeast Canada. To this end, transient climate change simulations spanning the 1950-2100 period are performed, with and without lakes, with the fifth generation of the Canadian Regional Climate Model (CRCM5), driven by the Canadian Earth System Model (CanESM2) at the lateral boundaries for Representative Concentration Pathway 8.5. An additional CRCM5 simulation, driven by European Centre for Medium-Range Weather Forecasts Re-Analysis Interim (ERA-Interim) for the 1980-2010 period, is performed in order to assess performance and boundary forcing errors. Performance errors are assessed by comparing the ERA-Interim-driven simulation with available observation datasets, for the 1980-2010 period, for selected variables: 2-m air temperature, total precipitation, snow water equivalent and streamflow. The validation results indicate reasonable model performance over the study region. Boundary forcing errors are studied by comparing ERA-Interim-driven simulation with the one driven by CanESM2 for the current 1980-2010 period, to identify regions and seasons for which projected changes should be interpreted with extra caution. Comparison of projected changes from the CRCM5 simulations with and without lakes suggest that the presence of lakes results in a dampening of projected increases to 2-m air temperature for all seasons almost everywhere in the study domain, with maximum dampening of the order of 2 °C occurring during winter, mostly in the vicinity of the lakes. As for

  6. Enrichment experiment changes microbial interactions in an ultra-oligotrophic environment

    PubMed Central

    Ponce-Soto, Gabriel Y.; Aguirre-von-Wobeser, Eneas; Eguiarte, Luis E.; Elser, James J.; Lee, Zarraz M.-P.; Souza, Valeria

    2015-01-01

    The increase of nutrients in water bodies, in particular nitrogen (N) and phosphorus (P) due to the recent expansion of agricultural and other human activities is accelerating environmental degradation of these water bodies, elevating the risk of eutrophication and reducing biodiversity. To evaluate the ecological effects of the influx of nutrients in an oligotrophic and stoichiometrically imbalanced environment, we performed a replicated in situ mesocosm experiment. We analyzed the effects of a N- and P-enrichment on the bacterial interspecific interactions in an experiment conducted in the Cuatro Cienegas Basin (CCB) in Mexico. This is a desert ecosystem comprised of several aquatic systems with a large number of microbial endemic species. The abundance of key nutrients in this basin exhibits strong stoichiometric imbalance (high N:P ratios), suggesting that species diversity is maintained mostly by competition for resources. We focused on the biofilm formation and antibiotic resistance of 960 strains of cultivated bacteria in two habitats, water and sediment, before and after 3 weeks of fertilization. The water habitat was dominated by Pseudomonas, while Halomonas dominated the sediment. Strong antibiotic resistance was found among the isolates at time zero in the nutrient-poor bacterial communities, but resistance declined in the bacteria isolated in the nutrient-rich environments, suggesting that in the nutrient-poor original environment, negative inter-specific interactions were important, while in the nutrient-rich environments, competitive interactions are not so important. In water, a significant increase in the percentage of biofilm-forming strains was observed for all treatments involving nutrient addition. PMID:25883593

  7. Enrichment experiment changes microbial interactions in an ultra-oligotrophic environment.

    PubMed

    Ponce-Soto, Gabriel Y; Aguirre-von-Wobeser, Eneas; Eguiarte, Luis E; Elser, James J; Lee, Zarraz M-P; Souza, Valeria

    2015-01-01

    The increase of nutrients in water bodies, in particular nitrogen (N) and phosphorus (P) due to the recent expansion of agricultural and other human activities is accelerating environmental degradation of these water bodies, elevating the risk of eutrophication and reducing biodiversity. To evaluate the ecological effects of the influx of nutrients in an oligotrophic and stoichiometrically imbalanced environment, we performed a replicated in situ mesocosm experiment. We analyzed the effects of a N- and P-enrichment on the bacterial interspecific interactions in an experiment conducted in the Cuatro Cienegas Basin (CCB) in Mexico. This is a desert ecosystem comprised of several aquatic systems with a large number of microbial endemic species. The abundance of key nutrients in this basin exhibits strong stoichiometric imbalance (high N:P ratios), suggesting that species diversity is maintained mostly by competition for resources. We focused on the biofilm formation and antibiotic resistance of 960 strains of cultivated bacteria in two habitats, water and sediment, before and after 3 weeks of fertilization. The water habitat was dominated by Pseudomonas, while Halomonas dominated the sediment. Strong antibiotic resistance was found among the isolates at time zero in the nutrient-poor bacterial communities, but resistance declined in the bacteria isolated in the nutrient-rich environments, suggesting that in the nutrient-poor original environment, negative inter-specific interactions were important, while in the nutrient-rich environments, competitive interactions are not so important. In water, a significant increase in the percentage of biofilm-forming strains was observed for all treatments involving nutrient addition. PMID:25883593

  8. Feeding behavior and social interactions of the Argentine ant Linepithema humile change with sucrose concentration.

    PubMed

    Sola, F J; Josens, R

    2016-08-01

    Liquid sugar baits are well accepted by the Argentine ant Linepithema humile and are suitable for the chemical control of this invasive species. We evaluated how sugar concentrations affect the foraging behavior of L. humile individuals. We quantified feeding variables for individual foragers (ingested load, feeding time and solution intake rate) when feeding on sucrose solutions of different concentrations, as well as post-feeding interactions with nestmates. Solutions of intermediate sucrose concentrations (10-30%) were the most consumed and had the highest intake rates, whereas solutions of high sucrose concentrations (60 and 70%) resulted in extended feeding times, low intake rates and ants having smaller crop loads. In terms of post-feeding interactions, individuals fed solutions of intermediate sucrose concentrations (20%) had the highest probability of conducting trophallaxis and the smallest latency to drop exposure (i.e. lowest time delay). Trophallaxis duration increased with increasing sucrose concentrations. Behavioral motor displays, including contacts with head jerking and walking with a gaster waggle, were lowest for individuals that ingested the more dilute sucrose solution (5%). These behaviors have been previously suggested to act as a communication channel for the activation and/or recruitment of nestmates. We show here that sucrose concentration affects feeding dynamics and modulates decision making related to individual behavior and social interactions of foragers. Our results indicate that intermediate sucrose concentrations (ca. 20%), appear to be most appropriate for toxic baits because they promote rapid foraging cycles, a high crop load per individual, and a high degree of stimulation for recruitment. PMID:27063551

  9. Influence of atmospheric and climatic change on plant-pathogen interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atmospheric change studies conducted in Free Air Concentration Enrichment (FACE) systems and open topped chambers have increased our understanding of how factors, such as rising CO2 and O3 levels, impact the development of plant disease epidemics. Using these systems, plant scientists have been able...

  10. Climate Change Course Impacts on the Individual, Their Future, and Interactions with Others

    ERIC Educational Resources Information Center

    Yanascavage, Christina

    2012-01-01

    This report explores the impacts a university climate change course has on those enrolled in the course. The research quantitatively measures and compares opinions, attitudes, and knowledge among groups, then qualitatively explores the responses of the group to identify course impacts. The results show reasons people enroll in the course, how they…

  11. Driver Behavioral Changes through Interactions with an Automatic Brake System for Collision Avoidance

    NASA Astrophysics Data System (ADS)

    Itoh, Makoto; Fujiwara, Yusuke; Inagaki, Toshiyuki

    This paper discusses driver's behavioral changes as a result of driver's use of an automatic brake system for preventing a rear-end collision from occurring. Three types of automatic brake systems are investigated in this study. Type 1 brake system applies a strong automatic brake when a collision is very imminent. Type 2 brake system initiates brake operation softly when a rear-end crash may be anticipated. Types 1 and 2 are for avoidance of a collision. Type 3 brake system, on the other hand, applies a strong automatic brake to reduce the damage when a collision can not be avoided. An experiment was conducted with a driving simulator in order to analyze the driver's possible behavioral changes. The results showed that the time headway (THW) during car following phase was reduced by use of an automatic brake system of any type. The inverse of time to collision (TTC), which is an index of the driver's brake timing, increased by use of Type 1 brake system when the deceleration rate of the lead vehicle was relatively low. However, the brake timing did not change when the drivers used Type 2 or 3 brake system. As a whole, dangerous behavioral changes, such as overreliance on a brake system, were not observed for either type of brake system.

  12. Changing of the Guards: Teacher-Student Interaction in the Intifada.

    ERIC Educational Resources Information Center

    Yair, Gad; Khatab, Nabil

    1995-01-01

    Maintains that, during the intifada (the revolt of Palestinians against Israeli occupation), the social order and power bases in Arab schools in East Jerusalem were transformed by significant social change. Discusses the rapid decline in teachers' authority and students' abuse of teachers and their property. (CFR)

  13. Communicating and Interacting: An Exploration of the Changing Roles of Media in CALL/CMC

    ERIC Educational Resources Information Center

    Hoven, Debra

    2006-01-01

    The sites of learning and teaching using CALL are shifting from CD-based, LAN-based, or stand-alone programs to the Internet. As this change occurs, pedagogical approaches to using CALL are also shifting to forms which better exploit the communication, collaboration, and negotiation aspects of the Internet. Numerous teachers and designers have…

  14. Interactions between chemical and climate stressors: A role for mechanistic toxicology in assessing climate change risks

    EPA Science Inventory

    Incorporation of global climate change (GCC) effects into regulatory assessments of chemical risk and injury requires an integrated examination of both chemical and non-chemical stressors. Environmental variables altered by GCC, such as temperature, precipitation, salinity and pH...

  15. CLIMATE CHANGE AND INTERACTING STRESSORS: IMPLICATIONS FOR CORAL REEF MANAGEMENT IN AMERICAN SAMOA

    EPA Science Inventory

    Coral reef ecosystems are sensitive to changes in climate, climate variability, land use, and UV radiation. This report was designed to take advantage of diverse research and monitoring efforts that are ongoing in American Samoa to: analyze and compile the results of multiple re...

  16. INTERACTIONS BETWEEN EVAPO-TRANSPIRATION AND ECOLOGICAL CHANGES IN JUNIPER WOODLANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    THE EXPANSION OF JUNIPER SPECIES INTO GRASSLAND AND SHRUB-STEPPE COMMUNITIES HAS OCCURRED ACROSS VAST AREAS AND AT A GLOBAL SCALE. IN MANY CASES WE HAVE DEVELOPED A REASONABLE UNDERSTANDING OF THE ECOLOGICAL OR SUCCESSIONAL CHANGES THAT ARE LIKELY WITH THE EXPANSION. IMPACTS ON EVAPO-TRANSPIRATION (...

  17. CLIMATE CHANGE AND INTERACTING STRESSORS: IMPLICATIONS FOR CORAL REEF MANAGEMENT IN AMERICAN SAMOA (Final Report)

    EPA Science Inventory

    The purpose of this report is to provide the coral reef managers of American Samoa, as well as other coral reef managers in the Pacific region, with some management options to help enhance the capacity of local coral reefs to resist the negative effects of climate change.

  18. Climate-soil Interactions: Global Change, Local Properties, and Ecological Sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global climate change is predicted to alter historic patterns of precipitation and temperature in rangelands globally. Vegetation community response to altered weather patterns will be mediated at the site level by local-scale properties that govern ecological potential, including geology, topograph...

  19. Changes in Patterns of Teacher Interaction in Primary Classrooms: 1976-96.

    ERIC Educational Resources Information Center

    Galton, Maurice; Hargreaves, Linda; Comber, Chris; Wall, Debbie; Pell, Tony

    1999-01-01

    Addresses the effectiveness of teaching methods in English primary school classrooms. Evaluates the interventions designed to change primary educators' teaching methods by replicating the Observational Research and Classroom Learning Evaluation (ORACLE) study that was originally conducted in 1976. Compares the results from the original study to…

  20. A Lake Sediment Record of Climate Change and Human-Environment Interactions in Southwestern China

    NASA Astrophysics Data System (ADS)

    Hillman, A.; Abbott, M.; Yu, J.; Steinman, B. A.

    2012-12-01

    The delivery of precipitation to southwestern China is largely through monsoon circulation which has evolved with changing insolation during the Holocene. Additionally, southwestern China has a long history of human activity including mining, metallurgy, agriculture, and pollution. Here, high-resolution sampling of a sediment core from Lake Xing Yun in the Yunnan Province (24°10'N, 102°46'E), a drought sensitive lake that behaves as a closed basin system, provides a sub-decadal record of changing climate and human activity in the late Holocene. We use δ18O and δ13C measurements of authigenic carbonate precipitated from the lake water, magnetic susceptibility values, and hydrologic mass balance models to document the timing, direction, and magnitude of moisture changes associated with variations in monsoon strength. We also use δ13C and δ15N measurements on organic matter, carbon to nitrogen ratios, and sediment trace metal concentrations to assess the impact of human activity on the Xing Yun watershed. The 2,500 year record highlights several transition periods related to both human and climate forcing. The rise of intensive irrigation of the lake associated with agriculture occurs at 900 AD, coincident with the rise of metallurgy and mining activities. The period from 1200 to 1360 AD is marked by an abrupt decrease in δ18O values indicating that lake-level rose at this time. We attribute this to a shifting demographic change associated with political upheaval, which is supported by the leveling off of trace metal concentrations and the stagnation of metallurgy and mining activities. The most pronounced feature of the record is a rapid transition to substantially lower lake levels that persisted from 1360-1850 AD. This can be attributed to the return of dramatic human modification to the watershed and changing monsoon strength associated with the Little Ice Age. Using hydrologic mass balance models we are able to quantify the change that can be ascribed to

  1. Surface changes and polymyxin interactions with a resistant strain of Klebsiella pneumoniae

    PubMed Central

    Velkov, Tony; Deris, Zakuan Z; Huang, Johnny X; Azad, Mohammad AK; Butler, Mark; Sivanesan, Sivashangarie; Kaminskas, Lisa M; Dong, Yao-Da; Boyd, Ben; Baker, Mark A; Cooper, Matthew A; Nation, Roger L; Li, Jian

    2014-01-01

    This study examines the interaction of polymyxin B and colistin with the surface and outer membrane components of a susceptible and resistant strain of Klebsiella pneumoniae. The interaction between polymyxins and bacterial membrane and isolated LPS from paired wild type and polymyxin-resistant strains of K. pneumoniae were examined with N-phenyl-1-naphthylamine (NPN) uptake, fluorometric binding and thermal shift assays, lysozyme and deoxycholate sensitivity assays, and by 1H NMR. LPS from the polymyxin-resistant strain displayed a reduced binding affinity for polymyxins B and colistin in comparison with the wild type LPS. The outer membrane NPN permeability of the resistant strain was greater compared with the susceptible strain. Polymyxin exposure enhanced the permeability of the outer membrane of the wild type strain to lysozyme and deoxycholate, whereas polymyxin concentrations up to 32 mg/ml failed to permeabilize the outer membrane of the resistant strain. Zeta potential measurements revealed that mid-logarithmic phase wild type cells exhibited a greater negative charge than the mid-logarithmic phase-resistant cells. Taken together, our findings suggest that the resistant derivative of K. pneumoniae can block the electrostatically driven first stage of polymyxin action, which thereby renders the hydrophobically driven second tier of polymyxin action on the outer membrane inconsequential. PMID:23887184

  2. Structural changes and intermolecular interactions of filled ice Ic structure for hydrogen hydrate under high pressure

    NASA Astrophysics Data System (ADS)

    Machida, S.; Hirai, H.; Kawamura, T.; Yamamoto, Y.; Yagi, T.

    2010-03-01

    High-pressure experiments of hydrogen hydrate were performed using a diamond anvil cell under conditions of 0.1-44.2 GPa and at room temperature. Also, high pressure Raman studies of solid hydrogen were performed in the pressure range of 0.1-43.7 GPa. X-ray diffractometry (XRD) for hydrogen hydrate revealed that a known high-pressure structure, filled ice Ic structure, of hydrogen hydrate transformed to a new high-pressure structure at approximately 35-40 GPa. A comparison of the Raman spectroscopy of a vibron for hydrogen molecules between hydrogen hydrate and solid hydrogen revealed that the extraction of hydrogen molecules from hydrogen hydrate occurred above 20 GPa. Also, the Raman spectra of a roton revealed that the rotation of hydrogen molecules in hydrogen hydrate was suppressed at around 20 GPa and that the rotation recovered under higher pressure. These results indicated that remarkable intermolecular interactions in hydrogen hydrate between neighboring hydrogen molecules and between guest hydrogen molecules and host water molecules might occur. These intermolecular interactions could produce the stability of hydrogen hydrate.

  3. Perceptual changes of interaction between hand and object in an experimental phantom hand.

    PubMed

    Inui, Nobuyuki; Masumoto, Junya

    2015-01-01

    The authors examined whether the wrist and elbow were perceived as flexed when a stick was fixed to the hand while the joints were extended during anesthesia. Ten healthy participants lay on their back on a bed with their eyes closed, and a stick was fixed to their right hand. Surprisingly, while the perceived position of the wrist and elbow moved toward flexion from 10 to 40 min after the ischemic block, the stick fixed to the hand was also perceived as having moved toward flexion from 10 to 20 min after the block. Such coupling the change in the perceived stick position with the change in body image suggests a new type of hand-object illusion. PMID:25272048

  4. Subduction interface property changes in relation to lithosphere-asthenosphere interactions

    NASA Astrophysics Data System (ADS)

    Arcay, D.; Lallemand, S.; Heuret, A.

    2011-12-01

    The subduction interplate domain (considered either as a plane or a channel, depending on the setting), is an interface of seismogenic coupling at the scale of one seismic cycle but also of kinematic decoupling on long-term time scales. The properties of this very particular interface is likely to affect not only the seismogenic potential of the subduction area but also the overall subduction process, as it influences its viability. However, the different mechanisms governing the subduction interplate dynamics remain poorly known. For instance, we observe a great variability of the downdip limit of the seismogenic zone, between 30 and 70 km. This depth might be controled by the brittle-ductile transition occuring along the subduction channel, and could thus depend on many parameters, such as temperature, pressure, compositional variations, strain rate,...This suggests a self-consistent equilibrium state of the subduction interplate, whose characteristics should depend on the subduction setting. Numerical simulations are performed to model the long-term equilibrium state of the subduction interplate when the diving lithosphere interacts with both the overriding plate and the surrounding convective mantle. The thermomechanical model combines a non-Newtonian viscous rheology and a pseudo-brittle rheology. Rock strength here depends on depth, temperature and stress, for both oceanic crust and mantle rocks. We study the evolution through time of, on one hand, the kinematic decoupling depth, and, on the other hand, of the brittle-ductile transition (BDT) depth simulated along the subduction interplate. The latter is used as a proxy for an upper bound of the downdip limit of the seismogenic zone. We previously showed that a convergence rate increase induced a shallowing of both the kinematic decoupling depth and the BDT, while it is generally thought that fast subductions promote interplate cooling and deepening. This comes from complex plate interactions with the

  5. Adapting to a Changing Environment: Modeling the Interaction of Directional Selection and Plasticity.

    PubMed

    Nunney, Leonard

    2016-01-01

    Human-induced habitat loss and fragmentation constrains the range of many species, making them unable to respond to climate change by moving. For such species to avoid extinction, they must respond with some combination of phenotypic plasticity and genetic adaptation. Haldane's "cost of natural selection" limits the rate of adaptation, but, although modeling has shown that in very large populations long-term adaptation can be maintained at rates substantially faster than Haldane's suggested limit, maintaining large populations is often an impossibility, so phenotypic plasticity may be crucial in enhancing the long-term survival of small populations. The potential importance of plasticity is in "buying time" for populations subject to directional environmental change: if genotypes can encompass a greater environmental range, then populations can maintain high fitness for a longer period of time. Alternatively, plasticity could be detrimental by lessening the effectiveness of natural selection in promoting genetic adaptation. Here, I modeled a directionally changing environment in which a genotype's adaptive phenotypic plasticity is centered around the environment where its fitness is highest. Plasticity broadens environmental tolerance and, provided it is not too costly, is favored by natural selection. However, a paradoxical result of the individually advantageous spread of plasticity is that, unless the adaptive trait is determined by very few loci, the long-term extinction risk of a population increases. This effect reflects a conflict between the short-term individual benefit of plasticity and a long-term detriment to population persistence, adding to the multiple threats facing small populations under conditions of climate change. PMID:26563131

  6. Energy Choices and Climate Change: A New Interactive Feature on Windows to the Universe

    NASA Astrophysics Data System (ADS)

    Gardiner, L. S.; Russell, R. M.; Ward, D.; Johnson, R. M.; Henderson, S.; Foster, S. Q.

    2009-12-01

    We have developed a new, self-paced online module to foster understanding of how choices made about energy production and energy use affect greenhouse gas emissions and climate change. The module, entitled “Energy Choices and Climate Change” is available on Windows to the Universe (www.windows.ucar.edu), an extensive educational Web site used by over 20 million people each year. “Energy Choices and Climate Change” provides a new way to look at issues related to energy and climate change, emphasizing the climate implications of the choices we make. “Energy Choices and Climate Change” allows users to explore two different scenarios through which they make decisions about energy production or use. In the “Ruler of the World” scenario, the user is given the authority to make decisions about the mix of energy sources that will be used worldwide with the aim of reducing emissions while meeting global energy demand and monitoring costs and societal implications. In “The Joules Family” scenario, the user makes decisions about how to change the way a hypothetical family of four uses energy at home and for transportation with the aim of reducing the family’s carbon emissions and fossil fuel use while keeping costs less than long-term savings. While this module is intended for a general public audience, an associated teacher’s guide provides support for secondary educators using the module with students. Windows to the Universe is a project of the University Corporation for Atmospheric Research Office of Education and Outreach. Funding for the Energy Choices and Climate Change online module was provided by the National Center for Atmospheric Research.

  7. Toward an integrated assessment of the interactions of climate change within a grassland biome: A program of measurements and modeling

    SciTech Connect

    Blad, B.L.; Easterling, W.E.

    1996-12-31

    The Great Plains Center for Global Environmental Change (GPRC), located at the University of Nebraska, has established a program focused on assessing the impact of climate change on a grassland biome. Primary research thrusts of the GPRC are: (1) the quantification of the consequences of climate change for managed and unmanaged ecosystems in grasslands, including assessment of the adaptive capacity of such ecosystems and any ecosystem-climate feedback; and (2) the measurement and modeling of net exchanges of energy-relevant, radiactivity-active trace gases between terrestrial grassland ecosystems and the atmosphere. The GPRC supports an integrated program involving scientists from several states and focusing on the Great Plains. It supports field-based process studies to improve understanding of the basic climate interactions with physical and biological systems. Particular emphasis is on modeling and measuring net carbon exchange in key Great Plains ecosystems. The GPRC supports development of climate change scenarios for impact analyses and the development of models to synthesize results of process studies that can estimate regional scale consequences of climate change on some aspect of the natural resources base of the Great Plains.

  8. Trophic cascades, invasive species and body-size hierarchies interactively modulate climate change responses of ecotonal temperate-boreal forest.

    PubMed

    Frelich, Lee E; Peterson, Rolf O; Dovčiak, Martin; Reich, Peter B; Vucetich, John A; Eisenhauer, Nico

    2012-11-01

    As the climate warms, boreal tree species are expected to be gradually replaced by temperate species within the southern boreal forest. Warming will be accompanied by changes in above- and below-ground consumers: large moose (Alces alces) replaced by smaller deer (Odocoileus virginianus) above-ground, and small detritivores replaced by larger exotic earthworms below-ground. These shifts may induce a cascade of ecological impacts across trophic levels that could alter the boreal to temperate forest transition. Deer are more likely to browse saplings of temperate tree species, and European earthworms favour seedlings of boreal tree species more than temperate species, potentially hindering the ability of temperate tree species to expand northwards. We hypothesize that warming-induced changes in consumers will lead to novel plant communities by changing the filter on plant species success, and that above- and below-ground cascades of trophic interactions will allow boreal tree species to persist during early phases of warming, leading to an abrupt change at a later time. The synthesis of evidence suggests that consumers can modify the climate change-induced transition of ecosystems. PMID:23007083

  9. Trophic cascades, invasive species and body-size hierarchies interactively modulate climate change responses of ecotonal temperate–boreal forest

    PubMed Central

    Frelich, Lee E.; Peterson, Rolf O.; Dovčiak, Martin; Reich, Peter B.; Vucetich, John A.; Eisenhauer, Nico

    2012-01-01

    As the climate warms, boreal tree species are expected to be gradually replaced by temperate species within the southern boreal forest. Warming will be accompanied by changes in above- and below-ground consumers: large moose (Alces alces) replaced by smaller deer (Odocoileus virginianus) above-ground, and small detritivores replaced by larger exotic earthworms below-ground. These shifts may induce a cascade of ecological impacts across trophic levels that could alter the boreal to temperate forest transition. Deer are more likely to browse saplings of temperate tree species, and European earthworms favour seedlings of boreal tree species more than temperate species, potentially hindering the ability of temperate tree species to expand northwards. We hypothesize that warming-induced changes in consumers will lead to novel plant communities by changing the filter on plant species success, and that above- and below-ground cascades of trophic interactions will allow boreal tree species to persist during early phases of warming, leading to an abrupt change at a later time. The synthesis of evidence suggests that consumers can modify the climate change-induced transition of ecosystems. PMID:23007083

  10. Interactions between predator- and diet-induced phenotypic changes in body shape of crucian carp.

    PubMed

    Andersson, Jens; Johansson, Frank; Söderlund, Tony

    2006-02-22

    Predator cues and diet, when studied separately, have been shown to affect body shape of organisms. Previous studies show that the morphological responses to predator absence/presence and diet may be similar, and hence could confound the interpretation of the causes of morphological differences found between groups of individuals. In this study, we simultaneously examined the effect of these two factors on body shape and performance in crucian carp in a laboratory experiment. Crucian carp (Carassius carassius) developed a shallow body shape when feeding on zooplankton prey and a deep body shape when feeding on benthic chironomids. In addition, the presence of chemical cues from a pike predator affected body shape, where a shallow body shape was developed in the absence of pike and a deep body shape was developed in the presence of pike. Foraging activity was low in the presence of pike cues and when chironomids were given as prey. Our results thereby suggest that the change in body shape could be indirectly mediated through differences in foraging activity. Finally, the induced body shape changes affected the foraging efficiency, where crucians raised on a zooplankton diet or in the absence of pike cues had a higher foraging success on zooplankton compared to crucian raised on a chironomid diet or in the presence of pike. These results suggest that body changes in response to predators can be associated with a cost, in terms of competition for resources. PMID:16615209

  11. Global biogeochemical cycles: Studies of interaction and change, some views on the strategy of approach

    NASA Technical Reports Server (NTRS)

    Bolin, B.

    1984-01-01

    The global biosphere is an exceedingly complex system. To gain an understanding of its structure and dynamic features, it is necessary to increase knowledge about the detailed processes, but also to develop models of how global interactions take place. Attempts to analyze the detailed physical, chemical and biological processes need, in this context, to be guided by an advancement of understanding of the latter. It is necessary to develop a strategy of data gathering that serves both these purposes simultaneously. climate research during the last decade may serve as a useful example of how to approach this difficult problem in a systematic way. Large programs for data collection may easily become rigid and costly. While realizing the necessity of a systematic and long lasting effort of observing the atmosphere, the oceans, land and life on Earth, such a program must remain flexible enough to permit the modifications and even sometimes improvisations that are necessary to maintain a viable program.

  12. Collisional state-changing of OH- rotations by interaction with Rb atoms in cold traps

    NASA Astrophysics Data System (ADS)

    González-Sánchez, L.; Carelli, F.; Gianturco, F. A.; Wester, R.

    2015-11-01

    We employ an accurate, ab initio potential energy surface (PES) which describes the electronic interaction energy between the molecular anion OH- (1Σ+) and the neutral rubidium atom Rb (2 S), to evaluate the elastic and inelastic cross sections over a range of energies representative of the conditions of low-T experiments in MOT traps, when combined with laser-cooled rubidium gas. The system is considered to be in its vibrational ground state, while the first four rotational levels are taken to be involved in the cooling and heating collisional processes that are computed here. The corresponding cooling and heating rates up to about 35 K are obtained from the calculations and compared with the recent results in a similar experiments, where He was the partner atom of the current anion.

  13. Evapotranspiration and River Discharge Interactions With Fire, Partial Success Restoration, and Climate Change

    NASA Astrophysics Data System (ADS)

    Cleverly, J. R.; Teet, S. B.; Thibault, J. R.; Dahm, C. N.

    2007-12-01

    Climate change is likely to have profound effects on water supplies in the southwestern United States. The largest rivers in this region are fed by snowmelt, which is predicted by the IPCC to decrease over the coming years. In the Middle Rio Grande of New Mexico, transpiration from phreatophytic vegetation can represent up to one-third of annual depletions. A flux tower network has been established in New Mexico, termed NM-EPSCoR Fluxnet, is providing valuable information on the eco-hydrological response of riparian and upland ecosystems to climate events (like drought), topographically-driven mesoscale forcing from katabatic and anabatic winds, ecosystem restoration, and post-fire recovery ecology. Following removal of non-native from below a cottonwood canopy causes greater insolation of the soil surface, doubling ground heat flux rates and inverting a portion diel energy balance from a heat sink (i.e., H < 0) to a heat source. The strongest cross-correlation (r = 0.5) between river flow and ET was observed when discharge was lagged 14 days behind ET. Neither drought nor fire modified this lag relationship. However, correlation between discharge and ET disappeared entirely following a canopy fire in 2006. Stomatal resistance cottonwood and co-occurring native and non-native vegetation was most strongly limited by vapor pressure deficit, although stomatal resistance was typically measured below this limit because of these plants' access to groundwater. It is also because of abundant groundwater along the Middle Rio Grande that drought has little effect on water and energy fluxes. As climate changes in this region and groundwater becomes more scarce, changes in community composition to non-native species is expected as native species become isolated from groundwater. With a strong understanding of the factors controlling the riparian water cycle, management of the riparian corridor can be achieved such that depletions are minimized while value of the ecosystem

  14. Mapping the interacting winds of Eta Carinae: Changes Across the Apastron

    NASA Astrophysics Data System (ADS)

    Gull, Theodore R.; Madura, T.; Corcoran, M. F.; Hamaguchi, K.; Teodoro, M.

    2014-01-01

    Since the May 2009 servicing mission to repair the Hubble Space Telescope, we have systematically mapped the central 1-2" region of Eta Carinae with the 0.1"-wide, long slit of the Space Telescope Imaging Spectrograph. Six mappings of selected forbidden emission lines began in the late recovery after the 2009.1 periastron event and now extend to phase 0.85 of Eta Carina's 5.54 year period. In addition to the recovery of the high state as depicted by [Fe III] (IP=16.6 eV) strictures and the stabilization of [Fe II] (IP=7.8 eV) features, we see components of at least three wind-blown shells that expand outward at 400 to 500 km/s. Virtually all forbidden emission originates from primary wind structures. The [Fe II] shells, moving at 470 km/s, are primary wind (420 km/s) structures slightly accelerated by the fast secondary wind (Teodoro et al, 2013 ApJ 773, L16T). The [Fe III] arcs, directly photo-ionized by the secondary star, also shift outward with time. Structures in both emissions shift in a general clockwork direction consistent with the derived orbital motion by Gull et al (2009 MNRAS 396, 1308) and revised by Madura et al (2012 MNRAS 420, 2064). With the continued development of the 3D hydrodynamic models we are able to compare the changing structures and determine limits to changes in the mass loss rate over this period of time. Additional mappings, to be obtained by seven additional HST visits, are scheduled at selected orbital phases to follow major changes in ionization structue due to the drop of high ionization to low ionization across the 2014.5 periastron passage. This work is funded by NASA grants to support HST research.

  15. Exploring the Effects of Climate Variability and Land Use Change on Groundwater-Surface Water Interactions

    NASA Astrophysics Data System (ADS)

    Duncan, L. L.; Hornberger, G. M.

    2013-12-01

    Locke Island is a 3.5-km long and 375-m wide differentially cemented sand and gravel, mid-channel island located in the Hanford Reach of the Columbia River. Across the eastern channel of the Columbia River from the island is the large Locke Island landslide complex, originating from the White Bluffs. There is evidence that landslides occurred along the White Bluffs in prehistoric times, within the last 11,000 years or so, and evidence of younger landslides, active in the last several hundred years. Irrigation of the land adjacent to the bluffs, and subsequent creation of unlined irrigation wastewater ponds behind the bluffs, is one of the hypotheses concerning the major cause of modern landsliding in this area, which began in the late 1960s. The estimated eight-fold increase in water delivered to the semi-arid area over the course of a decade resulted in an increase in the annual flow through the groundwater system. Similar to land use impacts, changes in the flow through groundwater systems as a result of variations in climate can alter groundwater-surface water exchange processes and connectivity too. We use a vertical two-dimensional finite element model to simulate variably saturated and unsaturated flow in the subsurface porous media along a cross-section of the hillslope-river-island continuum. Our work characterizes the hydraulic gradients and quantifies the outflows at the toe of the landslide and along the banks of the island, in response to creation of ponds behind the bluffs and decadal to multi-decadal changes in patterns of dryness. Understanding the effects of climate variability and land use change on groundwater-surface water exchanges, both separately and in combination, provides insight to the relative importance of these different mechanisms in landslide activity.

  16. Diurnal changes in reflectance factor due to Sun-row direction interactions

    NASA Technical Reports Server (NTRS)

    Bauer, M. E. (Principal Investigator); Vanderbilt, V. C.; Kollenkark, J. C.; Biehl, L. L.; Robinson, B. F.; Ranson, K. J.

    1981-01-01

    Over a two year period, data were collected regarding the canopies of soybeans grown in rows in planter boxes placed on a turntable in an effort to investigate changes in the spectral reflectance factor related to row direction, Sun direction, soil background, and crop development stage. Results demonstrate that the direction of rows in a soybean canopy can affect the reflectance factor of the canopy by as much as 230%. The results for the red spectral region tend to support the validity of canopy reflectance models; results for the infrared region do not.

  17. Dialogue: Interactive Alignment and Its Implications for Language Learning and Language Change

    NASA Astrophysics Data System (ADS)

    Garrod, Simon; Pickering, Martin J.

    This chapter discusses language processing during conversation. In particular, it considers why taking part in a conversation is more straightforward than speaking or listening in isolation. We argue that conversation is easy because speakers and listeners automatically align with each other at different linguistic levels (e.g., sound, grammar, meaning) which leads to alignment at the level of interpretation. This alignment process is reflected in the repetitiveness of dialogue at different levels and occurs both on the basis of local mechanisms of priming and more global mechanisms of routinization. We argue that the latter process may tell us something about both acquisition of language and historical processes of language change.

  18. Potential changes in atmospheric chemistry in the decades ahead: Climate and biosphere interactions and feedbacks

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.

    1991-10-01

    Atmospheric chemistry is a challenging area of research where much knowledge is needed if we are to continue to survive as a species. This paper outlines research needs in the decades ahead in this key area of scientific endeavor. Highlighted are areas of research that are likely to lead to climatic and biospheric impacts and have been given little attention in the past. In particular, the possible organic transformation chemistries that may lead to chemical and physical changes in tropospheric cloud chemistries are highlighted and emphasized as an area where research is needed in the future. 22 refs.

  19. Infrared Spectroscopic Study on Structural Change and Interfacial Interaction in Rubber Composites Filled with Silica-Kaolin Hybrid Fillers

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Guan, J.; Hu, H.; Gao, H.; Zhang, L.

    2016-07-01

    A series of natural rubber/styrene butadiene rubber/polybutadiene rubber composites was prepared with nanometer silica and micron kaolin by a dry modification process, mechanical compounding, and mold vulcanization. Fourier transform infrared spectroscopy and a scanning electron microscope were used to investigate the structural changes and interfacial interactions in composites. The results showed that the "seesaw" structure was formed particularly with the incorporation of silica particles in the preparation process, which would be beneficial to the dispersibility of fillers in the rubber matrix. The kaolinite platelets were generally arranged in directional alignment. Kaolinite with smaller particle size and low-defect structure was more stable in preparation, but kaolinite with larger particle size and high defect structure tended to change the crystal structure. The composite prepared in this research exhibited excellent mechanical and thermal properties.

  20. Lead isotopic evidence for evolutionary changes in magma-crust interaction, Central Andes, southern Peru

    NASA Astrophysics Data System (ADS)

    Barreiro, Barbara A.; Clark, Alan H.

    1984-07-01

    Lead isotopic measurements were made on Andean igneous rocks of Jurassic to Recent age in Moquegua and Tacna Departments, southernmost Peru, to clarify the petrogenesis of the rocks and, in particular, to investigate the effect of crustal thickness on rock composition. This location in the Cordillera Occidental is ideal for such a study because the ca. 2 Ga Precambrian basement rocks (Arequipa massif) have a distinct Pb isotopic signature which is an excellent tracer of crustal interaction, and because geomorphological research has shown that the continental crust was here thickened drastically in the later Tertiary. Seven samples of quartz diorites and granodiorites from the Ilo and Toquepala intrusive complexes, and seven samples of Toquepala Group subaerial volcanics were analyzed for Pb isotopic compositions. The plutonic rocks range in age from Jurassic to Eocene; the volcanic rocks are all Late Cretaceous to Eocene. With one exception, the Pb isotopic ratios are in the ranges 206Pb/ 204Pb= 18.52-18.75, 207Pb/ 204Pb= 15.58-15.65, and 208Pb/ 204Pb= 38.53-38.74. The data reflect very little or no interaction with old continental material of the Arequipa massif type. Lead from four Miocene Huaylillas Formation ash-flow tuffs, two Pliocene Capillune Formation andesites and five Quaternary Barroso Group andesites has lower 206Pb/ 204Pb than that in the pre-Miocene rocks, but relatively high 207Pb/ 204Pb and 208Pb/ 204Pb ( 206Pb/ 204Pb= 18.16-18.30, 207Pb/ 204Pb= 15.55-15.63, 208Pb/ 204Pb= 38.45-38.90). Tilton and Barreiro [9] have shown that contamination by Arequipa massif granulites can explain the isotopic composition of the Barosso Group lavas, and the new data demonstrate that this effect is evident, to varying degrees, in all the analysed Neogene volcanic rocks. The initial incorporation of such basement material into the magma coincided with the Early Miocene uplift of this segment of the Cordillera Occidental [32], and thus with the creation of a thick

  1. The Mechanisms of Natural Variability and its Interaction with Anthropogenic Climate Change Final Report

    SciTech Connect

    Vallis, Geoffrey K.

    2015-02-01

    The project had two main components. The first concerns estimating the climate sensitivity in the presence of forcing uncertainty and natural variability. Climate sensitivity is the increase in the average surface temperature for a given increase in greenhouse gases, for example a doubling of carbon dioxide. We have provided new, probabilistic estimates of climate sensitivity using a simple climate model an the observed warming in the 20th century, in conjunction with ideas in data assimilation and parameter estimation developed in the engineering community. The estimates combine the uncertainty in the anthropogenic aerosols with the uncertainty arising because of natural variability. The second component concerns how the atmospheric circulation itself might change with anthropogenic global warming. We have shown that GCMs robustly predict an increase in the length scale of eddies, and we have also explored the dynamical mechanisms whereby there might be a shift in the latitude of the jet stream associated with anthropogenic warming. Such shifts in the jet might cause large changes in regional climate, potentially larger than the globally-averaged signal itself. We have also shown that the tropopause robustly increases in height with global warming, and that the Hadley Cell expands, and that the expansion of the Hadley Cell is correlated with the polewards movement of the mid-latitude jet.

  2. Electrostatic unfolding and interactions of albumin driven by pH changes: a molecular dynamics study.

    PubMed

    Baler, K; Martin, O A; Carignano, M A; Ameer, G A; Vila, J A; Szleifer, I

    2014-01-30

    A better understanding of protein aggregation is bound to translate into critical advances in several areas, including the treatment of misfolded protein disorders and the development of self-assembling biomaterials for novel commercial applications. Because of its ubiquity and clinical potential, albumin is one of the best-characterized models in protein aggregation research; but its properties in different conditions are not completely understood. Here, we carried out all-atom molecular dynamics simulations of albumin to understand how electrostatics can affect the conformation of a single albumin molecule just prior to self-assembly. We then analyzed the tertiary structure and solvent accessible surface area of albumin after electrostatically triggered partial denaturation. The data obtained from these single protein simulations allowed us to investigate the effect of electrostatic interactions between two proteins. The results of these simulations suggested that hydrophobic attractions and counterion binding may be strong enough to effectively overcome the electrostatic repulsions between the highly charged monomers. This work contributes to our general understanding of protein aggregation mechanisms, the importance of explicit consideration of free ions in protein solutions, provides critical new insights about the equilibrium conformation of albumin in its partially denatured state at low pH, and may spur significant progress in our efforts to develop biocompatible protein hydrogels driven by electrostatic partial denaturation. PMID:24393011

  3. Electrostatic Unfolding and Interactions of Albumin Driven by pH Changes: A Molecular Dynamics Study

    PubMed Central

    2015-01-01

    A better understanding of protein aggregation is bound to translate into critical advances in several areas, including the treatment of misfolded protein disorders and the development of self-assembling biomaterials for novel commercial applications. Because of its ubiquity and clinical potential, albumin is one of the best-characterized models in protein aggregation research; but its properties in different conditions are not completely understood. Here, we carried out all-atom molecular dynamics simulations of albumin to understand how electrostatics can affect the conformation of a single albumin molecule just prior to self-assembly. We then analyzed the tertiary structure and solvent accessible surface area of albumin after electrostatically triggered partial denaturation. The data obtained from these single protein simulations allowed us to investigate the effect of electrostatic interactions between two proteins. The results of these simulations suggested that hydrophobic attractions and counterion binding may be strong enough to effectively overcome the electrostatic repulsions between the highly charged monomers. This work contributes to our general understanding of protein aggregation mechanisms, the importance of explicit consideration of free ions in protein solutions, provides critical new insights about the equilibrium conformation of albumin in its partially denatured state at low pH, and may spur significant progress in our efforts to develop biocompatible protein hydrogels driven by electrostatic partial denaturation. PMID:24393011

  4. Mechanisms driving change: altered species interactions and ecosystem function through global warming.

    PubMed

    Traill, Lochran W; Lim, Matthew L M; Sodhi, Navjot S; Bradshaw, Corey J A

    2010-09-01

    1. We review the mechanisms behind ecosystem functions, the processes that facilitate energy transfer along food webs, and the major processes that allow the cycling of carbon, oxygen and nitrogen, and use case studies to show how these have already been, and will continue to be, altered by global warming. 2. Increased temperatures will affect the interactions between heterotrophs and autotrophs (e.g. pollination and seed dispersal), and between heterotrophs (e.g. predators-prey, parasites/pathogens-hosts), with generally negative ramifications for important ecosystem services (functions that provide direct benefit to human society such as pollination) and potential for heightened species co-extinction rates. 3. Mitigation of likely impacts of warming will require, in particular, the maintenance of species diversity as insurance for the provision of basic ecosystem services. Key to this will be long-term monitoring and focused research that seek to maintain ecosystem resilience in the face of global warming. 4. We provide guidelines for pursuing research that quantifies the nexus between ecosystem function and global warming. These include documentation of key functional species groups within systems, and understanding the principal outcomes arising from direct and indirect effects of a rapidly warming environment. Localized and targeted research and monitoring, complemented with laboratory work, will determine outcomes for resilience and guide adaptive conservation responses and long-term planning. PMID:20487086

  5. Interactions between climate change, hydrology and soil erosion in different climatic zones in Italy

    NASA Astrophysics Data System (ADS)

    Capra, A.; Pavanelli, D.

    2010-03-01

    In Italy, during last century the mean annual temperature (Tym) increased by 0.4°C/100 years in Northern areas (N) (continental zone) and by 0.7°C/100 years in Central (C) and Southern (S) parts (peninsular zones). A negative trend of annual rainfall (Py) was evident in both N and S areas. Extreme events had different tendencies, corresponding to increases in rainfall intensity and in drought conditions in both N and S areas. Climate change affects both vegetation water availability and runoff and erosion. Different results on climatic trends were obtained for smaller sub-regions of Southern Italy. Therefore, climate change studies at a regional level should also account for geographical factors (e.g. distance from the sea, elevation, aspect). In the current study trend in precipitation recorded during last century in three different climatic zones in Italy were investigated and compared. The three zones are: a typical Tuscan-Emilian Apennines watershed (the Reno river) located in the continental area, the Calabria region located in the peninsular zone, and the Sicily region, an island located in the South of Italy. For Reno river mountain watershed (2.597 km2), an attempt was made to gain some knowledge about the changes in the 20th century of the land use and of the climate, connected to the erosion soil risk. The Italian Apennines, from the 16th century, were exploited for farming and for agro forestry and pastoral activities. This human activities encouraged intense erosive processes, but an important factor controlling the intense morphodynamics is the contemporary increase of rainfall in the "Little Ice Age". From the beginning of the 1900, have been led two conflicting and simultaneous phenomena: population moving both to cities and valley bottoms and agricultural mechanization. Their consequences have been evident on land use: abandonment of unproductive fields, of forestry practices and enlargement of the remaining plots. The Calabria region is a long

  6. Climate Risk and Vulnerability in the Caribbean and Gulf of Mexico Region: Interactions with Spatial Population and Land Cover Change

    NASA Astrophysics Data System (ADS)

    Chen, R. S.; Levy, M.; Baptista, S.; Adamo, S.

    2010-12-01

    Vulnerability to climate variability and change will depend on dynamic interactions between different aspects of climate, land-use change, and socioeconomic trends. Measurements and projections of these changes are difficult at the local scale but necessary for effective planning. New data sources and methods make it possible to assess land-use and socioeconomic changes that may affect future patterns of climate vulnerability. In this paper we report on new time series data sets that reveal trends in the spatial patterns of climate vulnerability in the Caribbean/Gulf of Mexico Region. Specifically, we examine spatial time series data for human population over the period 1990-2000, time series data on land use and land cover over 2000-2009, and infant mortality rates as a proxy for poverty for 2000-2008. We compare the spatial trends for these measures to the distribution of climate-related natural disaster risk hotspots (cyclones, floods, landslides, and droughts) in terms of frequency, mortality, and economic losses. We use these data to identify areas where climate vulnerability appears to be increasing and where it may be decreasing. Regions where trends and patterns are especially worrisome include coastal areas of Guatemala and Honduras.

  7. l- and n-changing collisions during interaction of a pulsed beam of Li Rydberg atoms with CO2

    NASA Astrophysics Data System (ADS)

    Dubreuil, B.; Harnafi, M.

    1989-07-01

    The pulsed Li atomic beam produced in our experiment is based on controlled transversely-excited-atmospheric CO2 laser-induced ablation of a Li metal target. The atomic beam is propagated in vacuum or in CO2 gas at low pressure. Atoms in the beam are probed by laser-induced fluorescence spectroscopy. This allows the determination of time-of-flight and velocity distributions. Li Rydberg states (n=5-13) are populated in the beam by two-step pulsed-laser excitation. The excited atoms interact with CO2 molecules. l- and n-changing cross sections are deduced from the time evolution of the resonant or collision-induced fluorescence following this selective excitation. l-changing cross sections of the order of 104 AṦ are measured; they increase with n as opposed to the plateau observed for Li* colliding with a diatomic molecule. This behavior is qualitatively well explained in the framework of the free-electron model. n-->n' changing processes with large cross sections (10-100 AṦ) are also observed even in the case of large electronic energy change (ΔEnn'>103 cm-1). These results can be interpreted in terms of resonant-electronic to vibrational energy transfers between Li Rydberg states and CO2 vibrational modes.

  8. Shifting Regimes and Changing Interactions in the Lake Washington, U.S.A., Plankton Community from 1962–1994

    PubMed Central

    Francis, Tessa B.; Wolkovich, Elizabeth M.; Scheuerell, Mark D.; Katz, Stephen L.; Holmes, Elizabeth E.; Hampton, Stephanie E.

    2014-01-01

    Understanding how changing climate, nutrient regimes, and invasive species shift food web structure is critically important in ecology. Most analytical approaches, however, assume static species interactions and environmental effects across time. Therefore, we applied multivariate autoregressive (MAR) models in a moving window context to test for shifting plankton community interactions and effects of environmental variables on plankton abundance in Lake Washington, U.S.A. from 1962–1994, following reduced nutrient loading in the 1960s and the rise of Daphnia in the 1970s. The moving-window MAR (mwMAR) approach showed shifts in the strengths of interactions between Daphnia, a dominant grazer, and other plankton taxa between a high nutrient, Oscillatoria-dominated regime and a low nutrient, Daphnia-dominated regime. The approach also highlighted the inhibiting influence of the cyanobacterium Oscillatoria on other plankton taxa in the community. Overall community stability was lowest during the period of elevated nutrient loading and Oscillatoria dominance. Despite recent warming of the lake, we found no evidence that anomalous temperatures impacted plankton abundance. Our results suggest mwMAR modeling is a useful approach that can be applied across diverse ecosystems, when questions involve shifting relationships within food webs, and among species and abiotic drivers. PMID:25338087

  9. Changes of the Ionosphere Caused By the Interaction Between the Quasi-Two-Day Wave and Tides

    NASA Astrophysics Data System (ADS)

    Yue, J.; Wang, W.; Chang, L. C.

    2014-12-01

    Traveling planetary waves, such as the quasi-two-day wave (QTDW), are one essential element of the mesosphere and lower thermosphere dynamics. These planetary waves have been observed to cause strong ionospheric day-to-day variations. We have understood that the QTDW can impact the thermosphere and ionosphere either by directly penetrating into the lower thermosphere and modulating E-region dynamo in a period of about 2-days, or by enhancing mixing and decreasing thermosphere O/N2 and in ionospheric electron density. In this work, we introduce the third mechanism of how the QTDW impacts the ionosphere, the QTDW-tidal interactions occurring in the mesosphere and lower thermosphere (MLT). We employ the NCAR TIME-GCM to simulate the interaction between the QTDW and tides, and the impact of this interaction on the ionospheric E-region dynamo, equatorial fountain effect, and F-region plasma density. We find that the tidal amplitudes and phases are dramatically altered during strong QTDW events during post-solstice. In particular, the amplitudes of the migrating tides can decrease as much as 20-30%. The changed tides result in different dynamo electric field, vertical ion drift, and thus different diurnal and semidiurnal cycles in F-region electron density.

  10. Tips 'n' Tricks for Teachers: Using the latest interactive multimedia from NASA's Climate Change website in the classroom

    NASA Astrophysics Data System (ADS)

    Tenenbaum, L. F.; Jackson, R.; Greene, M.; Climate Communication Team

    2010-12-01

    The demand for new, engaging and inspiring educational materials in the areas of Earth and climate science is greatly increasing. In response to this need, new educational content for the "Climate Change: NASA’s Eyes on the Earth" website http://climate.nasa.gov/, was developed, notably an online interactive “Global Ice Viewer” that covers the topic of global ice mass loss by depicting glaciers around the world, Arctic sea ice extent, Greenland glacial calving, and Antarctic ice shelf break up. The new “Global Ice Viewer” features ground based and remote images, narrated and time lapse videos, time series animations, NASA and other scientific data, plus maps, in a visually engaging and interactive format. A downloadable “Tips ‘n’ Tricks for Teachers” guide to using the website in the classroom was also developed. Using Internet interactive features in the classroom improves student participation, topic comprehension, scientific curiosity and interest in Earth and climate science across diverse student populations.

  11. CryoEM analysis of capsid assembly and structural changes upon interactions with a host restriction factor, TRIM5α.

    PubMed

    Zhao, Gongpu; Zhang, Peijun

    2014-01-01

    After virus fusion with a target cell, the viral core is released into the host cell cytoplasm and undergoes a controlled disassembly process, termed uncoating, before or as reverse transcription takes place. The cellular protein TRIM5α is a host cell restriction factor that blocks HIV-1 infection in rhesus macaque cells by targeting the viral capsid and inducing premature uncoating. The molecular mechanism of the interaction between capsid and TRIM5α remains unclear. Here, we describe an approach that utilizes cryo-electron microscopy (cryoEM) to examine the structural changes exerted on HIV-1 capsid (CA) assembly by TRIM5α binding. The TRIM5α interaction sites on CA assembly were further dissected by combining cryoEM with pair-wise cysteine mutations that crosslink CA either within a CA hexamer or between CA hexamers. Based on the structural information from cryoEM and crosslinking results from in vitro CA assemblies and purified intact HIV-1 cores, we demonstrate that direct binding of TRIM5α CC-SPRY domains to the viral capsid results in disruption and fragmentation of the surface lattice of HIV-1 capsid, specifically at inter-hexamer interfaces. The method described here can be easily adopted to study other important interactions in multi-protein complexes. PMID:24158810

  12. Interactive effects of climate change and eutrophication on the dinoflagellate-bearing benthic foraminifer Marginopora vertebralis

    NASA Astrophysics Data System (ADS)

    Uthicke, S.; Vogel, N.; Doyle, J.; Schmidt, C.; Humphrey, C.

    2012-06-01

    Elevated sea surface temperatures caused by global climate change and increased nutrient concentrations resulting from land runoff both are stressors for calcifying coral reef organisms. Here, we test the hypothesis that increased temperature leads to bleaching in dinoflagellate-bearing foraminifera similar to corals and that increased nutrients through runoff can exaggerate stress on the holobiont. In an experiment manipulating temperatures alone, we have shown that mortality of Marginopora vertebralis increased with temperatures. Most individuals died after 7 days at 34°C, ~5°C above current summer maxima. Survival at 37 days was >98% at 28°C. After 7 days of exposure to 31 or 32°C, photosynthesis of the endosymbionts was compromised, as indicated by several photophysiological parameters (effective quantum yield and apparent photosynthetic rate). In a flow-though experiment manipulating both temperature (three levels, 26, 29 and 31°C) and nitrate concentrations (3 levels, ~0.5, 1.0 and 1.4 μmol l-1 NO3 -), elevated temperature had a significant negative effect on most parameters measured. At 31°C, most photopigments (measured by UPLC) in the foraminifera were significantly reduced. The only pigment that increased was the photoprotective diatoxanthin. Several other parameters measured (maximum and effective quantum yield, O2 production in light, organic carbon contents) also significantly decreased with temperature. Optode-based respirometry demonstrated that the presence of symbionts at elevated temperatures represents a net carbon loss for the host. Growth rates of M. vertebralis and mortality at the end of the experiment were significantly affected by both temperature increase and nitrate addition. We conclude that these foraminifera bleach in a similar fashion to corals and that global sea surface temperature change and nitrate increases are stressors for these protists. Furthermore, this provides support for the hypothesis that management of local

  13. Trophic interactions between viruses, bacteria and nanoflagellates under various nutrient conditions and simulated climate change.

    PubMed

    Bouvy, M; Bettarel, Y; Bouvier, C; Domaizon, I; Jacquet, S; Le Floc'h, E; Montanié, H; Mostajir, B; Sime-Ngando, T; Torréton, J P; Vidussi, F; Bouvier, T

    2011-07-01

    Population dynamics in the microbial food web are influenced by resource availability and predator/parasitism activities. Climatic changes, such as an increase in temperature and/or UV radiation, can also modify ecological systems in many ways. A series of enclosure experiments was conducted using natural microbial communities from a Mediterranean lagoon to assess the response of microbial communities to top-down control [grazing by heterotrophic nanoflagellates (HNF), viral lysis] and bottom-up control (nutrients) under various simulated climatic conditions (temperature and UV-B radiations). Different biological assemblages were obtained by separating bacteria and viruses from HNF by size fractionation which were then incubated in whirl-Pak bags exposed to an increase of 3°C and 20% UV-B above the control conditions for 96 h. The assemblages were also provided with an inorganic and organic nutrient supply. The data show (i) a clear nutrient limitation of bacterial growth under all simulated climatic conditions in the absence of HNF, (ii) a great impact of HNF grazing on bacteria irrespective of the nutrient conditions and the simulated climatic conditions, (iii) a significant decrease in burst size (BS) (number of intracellular lytic viruses per bacterium) and a significant increase of VBR (virus to bacterium ratio) in the presence of HNF, and (iv) a much larger temperature effect than UV-B radiation effect on the bacterial dynamics. These results show that top-down factors, essentially HNF grazing, control the dynamics of the lagoon bacterioplankton assemblage and that short-term simulated climate changes are only a secondary effect controlling microbial processes. PMID:21605305

  14. Does vegetation type matter? Plant-soil interactions change urban rain garden hydrology

    NASA Astrophysics Data System (ADS)

    Johnston, M. R.; Balster, N. J.

    2009-12-01

    Residential infiltration basins or rain gardens are being installed at an ever-increasing rate across the urban landscape, yet their impact on the urban hydrologic cycle remains largely untested. Specifically, because rain garden design varies considerably, we know little about how plant-soil dynamics control their hydrologic function. In a controlled field experiment with closed-system rain gardens, we tested the hydrologic response of three vegetation treatments common in rain garden design (shrubs, wet-mesic prairie, turfgrass). We used a complete, randomized block design in which each vegetative treatment was replicated three times. Each rain garden represented 17% of a contributing roof area where stormwater was collected and then applied following precipitation events. We continuously monitored stormwater input, soil water content, and soil exfiltration to assess differences in the hydrologic function of each rain garden. Overall, vegetation type significantly changed the magnitude and timing of the hydrologic response. During the months of June and July, 2009, the rain gardens planted with shrubs, prairie, and turfgrass all reduced the volume of soil exfiltration by 50%, 30%, and 17%, respectively, relative to the non-vegetated controls. Similarly, depending on storm magnitude and antecedent soil moisture, vegetation type significantly decreased the mean peak flow rate of exfiltration (p < 0.001), as well as the duration of the exfiltration response (p < 0.0001). The flashiest hydrologic responses (i.e. shortest lag time, highest peak flow rate) were observed in the turfgrass gardens. We explain these vegetative-mediated responses in hydrology relative to differences in infiltration, aboveground dry mass, root dynamics, and transpirative loss. Our data suggest that changing the vegetation type of urban rain gardens yields marked differences in the hydrologic budget via shifts in ecohydrological processes.

  15. JORNEX: An airborne campaign to quantify rangeland vegetation change and plant community-atmospheric interactions

    SciTech Connect

    Ritchie, J.C.; Rango, A.; Kustas, W.P.

    1996-11-01

    The Jornada Experimental Range in New Mexico provides a unique opportunity to integrate hydrologic-atmospheric fluxes and surface states, vegetation types, cover, and distribution, and vegetation response to changes in hydrologic states and atmospheric driving forces. The Jornada Range is the site of a long-term ecological research program to investigate the processes leading to desertification. In concert with ongoing ground measurements, remotely sensed data are being collected from ground, airborne, and satellite platforms during JORNEX (the JORNada Experiment) to provide spatial and temporal distribution of vegetation state using laser altimeter and multispectral aircraft and satellite data and surface energy balance estimates from a combination of parameters and state variables derived from remotely sensed data. These measurements will be used as inputs to models to quantify the hydrologic budget and the plant response to changes in components in the water and energy balance. Intensive three day study periods for ground and airborne campaigns have been made in May 1995 (dry season) and September 1995 (wet season), February 1996 (Winter) and are planned for wet and dry seasons of 1996. An airborne platform is being used to collect thermal, multispectral, 3-band video, and laser altimetry profile data. Bowen ratio-energy balance stations were established in shrub and grass communities in May 1995 and are collecting data continuously. Additional energy flux measurements were made using eddy correlation techniques during the September 1995 campaign. Ground-based measurements during the intensive campaigns include thermal and multispectral measurements made using yoke-based platforms and hand-held instruments, LAI, and other vegetation data. Ground and aircraft measurements are acquired during Landsat overpasses so the effect of scale on measurements can be studied. This paper discusses preliminary results from the 1995 airborne campaign. 24 refs., 13 figs., 1 tab.

  16. Complex interactions between climate change and toxicants: evidence that temperature variability increases sensitivity to cadmium.

    PubMed

    Kimberly, David A; Salice, Christopher J

    2014-07-01

    The Intergovernmental Panel on Climate Change projects that global climate change will have significant impacts on environmental conditions including potential effects on sensitivity of organisms to environmental contaminants. The objective of this study was to test the climate-induced toxicant sensitivity (CITS) hypothesis in which acclimation to altered climate parameters increases toxicant sensitivity. Adult Physa pomilia snails were acclimated to a near optimal 22 °C or a high-normal 28 °C for 28 days. After 28 days, snails from each temperature group were challenged with either low (150 μg/L) or high (300 μg/L) cadmium at each temperature (28 or 22 °C). In contrast to the CITS hypothesis, we found that acclimation temperature did not have a strong influence on cadmium sensitivity except at the high cadmium test concentration where snails acclimated to 28 °C were more cadmium tolerant. However, snails that experienced a switch in temperature for the cadmium challenge, regardless of the switch direction, were the most sensitive to cadmium. Within the snails that were switched between temperatures, snails acclimated at 28 °C and then exposed to high cadmium at 22 °C exhibited significantly greater mortality than those snails acclimated to 22 °C and then exposed to cadmium at 28 °C. Our results point to the importance of temperature variability in increasing toxicant sensitivity but also suggest a potentially complex cost of temperature acclimation. Broadly, the type of temporal stressor exposures we simulated may reduce overall plasticity in responses to stress ultimately rendering populations more vulnerable to adverse effects. PMID:24623389

  17. Spectral characterization of the binding and conformational changes of serum albumins upon interaction with an anticancer drug, anastrozole

    NASA Astrophysics Data System (ADS)

    Punith, Reeta; Seetharamappa, J.

    2012-06-01

    The present study employed different optical spectroscopic techniques viz., fluorescence, FTIR, circular dichroism (CD) and UV-vis absorption spectroscopy to investigate the mechanism of interaction of an anticancer drug, anastrozole (AZ) with transport proteins viz., bovine serum albumin (BSA) and human serum albumin (HSA). The drug, AZ quenched the intrinsic fluorescence of protein and the analysis of results revealed the presence of dynamic quenching mechanism. The binding characteristics of drug-protein were computed. The thermodynamic parameters, enthalpy change (ΔH°) and entropy change (ΔS°) were calculated to be +92.99 kJ/mol and +159.18 J/mol/K for AZ-BSA and, +99.43 kJ/mol and +159.19 J/mol/K for AZ-HSA, respectively. These results indicated that the hydrophobic forces stabilized the interaction between the drug and protein. CD, FTIR, absorption, synchronous and 3D fluorescence results indicated that the binding of AZ to protein induced structural perturbation in both serum albumins. The distance, r between the drug and protein was calculated based on the theory of Förster's resonance energy transfer and found to be 5.9 and 6.24 nm, respectively for AZ-BSA and AZ-HSA.

  18. First-principles study of magnetic interactions in 3d transition metal-doped phase-change materials

    NASA Astrophysics Data System (ADS)

    Fukushima, T.; Katayama-Yoshida, H.; Sato, K.; Fujii, H.; Rabel, E.; Zeller, R.; Dederichs, P. H.; Zhang, W.; Mazzarello, R.

    2014-10-01

    Recently, magnetic phase-change materials have been synthesized experimentally by doping with 3d transition metal impurities. Here, we investigate the electronic structure and the magnetic properties of the prototypical phase-change material Ge2Sb2Te5 (GST) doped with V, Cr, Mn, and Fe by density functional calculations. Both the supercell method and the coherent potential approximation (CPA) are employed to describe this complex substitutionally disordered system. As regards the first approach, we consider a large unit cell containing 1000 sites to model the random distribution of the cations and of the impurities in doped cubic GST. Such a large-scale electronic structure calculation is performed using the program kkrnano, where the full potential screened Korringa-Kohn-Rostoker Green's function method is optimized by a massively parallel linear scaling (order-N) all-electron algorithm. Overall, the electronic structures and magnetic exchange coupling constants calculated by kkrnano agree quite well with the CPA results. We find that ferromagnetic states are favorable in the cases of V and Cr doping, due to the double exchange mechanism, whereas antiferromagnetic superexchange interactions appear to be dominant for Fe- and Mn-doped GST. The ferromagnetic interaction is particularly strong in the case of Cr. As a result, high Curie temperatures close to room temperatures are obtained for large Cr concentrations of 15%.

  19. Seasonal changes in infaunal community structure in a hypertrophic brackish canal: Effects of hypoxia, sulfide, and predator-prey interaction.

    PubMed

    Kanaya, Gen; Nakamura, Yasuo; Koizumi, Tomoyoshi; Yamada, Katsumasa

    2015-07-01

    We conducted a one-year survey of macrozoobenthic community structure at 5 stations in a eutrophic canal in inner Tokyo Bay, focusing on the impacts of hypoxia, sediment H2S, and species interaction in the littoral soft-bottom habitats. Complete defaunation or decreasing density of less-tolerant taxa occurred under hypoxia during warmer months, especially at subtidal or sulfidic stations; this was followed by rapid recolonization by opportunistic polychaetes in fall-winter. Sedimentary H2S increased the mortality of macroinvertebrates under hypoxia or delayed population recovery during recolonization. The density of several polychaetes (e.g., Pseudopolydora reticulata) declined in winter, coincident with immigration of the predator Armandia lanceolata. This suggests that absence of A. lanceolata under moderate hypoxia enabled the proliferation of prey taxa. We conclude that oxygen concentration, sediment H2S, and hypoxia-induced changes in species interactions are potential drivers for spatiotemporal changes in macrozoobenthic assemblage structure in hypoxia-prone soft-bottom communities. PMID:25925266

  20. The effects on human health from stratospheric ozone depletion and its interactions with climate change.

    PubMed

    Norval, M; Cullen, A P; de Gruijl, F R; Longstreth, J; Takizawa, Y; Lucas, R M; Noonan, F P; van der Leun, J C

    2007-03-01

    Ozone depletion leads to an increase in the ultraviolet-B (UV-B) component (280-315 nm) of solar ultraviolet radiation (UVR) reaching the surface of the Earth with important consequences for human health. Solar UVR has many harmful and some beneficial effects on individuals and, in this review, information mainly published since the previous report in 2003 (F. R. de Gruijl, J. Longstreth, M. Norval, A. P. Cullen, H. Slaper, M. L. Kripke, Y. Takizawa and J. C. van der Leun, Photochem. Photobiol. Sci., 2003, 2, pp. 16-28) is discussed. The eye is exposed directly to sunlight and this can result in acute or long-term damage. Studying how UV-B interacts with the surface and internal structures of the eye has led to a further understanding of the location and pathogenesis of a number of ocular diseases, including pterygium and cataract. The skin is also exposed directly to solar UVR, and the development of skin cancer is the main adverse health outcome of excessive UVR exposure. Skin cancer is the most common form of malignancy amongst fair-skinned people, and its incidence has increased markedly in recent decades. Projections consistently indicate a further doubling in the next ten years. It is recognised that genetic factors in addition to those controlling pigment variation can modulate the response of an individual to UVR. Several of the genetic factors affecting susceptibility to the development of squamous cell carcinoma, basal cell carcinoma and melanoma have been identified. Exposure to solar UVR down-regulates immune responses, in the skin and systemically, by a combination of mechanisms including the generation of particularly potent subsets of T regulatory cells. Such immunosuppression is known to be a crucial factor in the generation of skin cancers. Apart from a detrimental effect on infections caused by some members of the herpesvirus and papillomavirus families, the impact of UV-induced immunosuppression on other microbial diseases and vaccination

  1. TBBPA chronic exposure produces sex-specific neurobehavioral and social interaction changes in adult zebrafish.

    PubMed

    Chen, Jiangfei; Tanguay, Robert L; Simonich, Michael; Nie, Shangfei; Zhao, Yuxin; Li, Lelin; Bai, Chenglian; Dong, Qiaoxiang; Huang, Changjiang; Lin, Kuangfei

    2016-01-01

    The toxicity of tetrabromobisphenol A (TBBPA) has been extensively studied because of its high production volume. TBBPA is toxic to aquatic fish based on acute high concentration exposure tests, and few studies have assessed the behavioral effects of low concentration chronic TBBPA exposures in aquatic organisms. The present study defined the developmental and neurobehavioral effects associated with exposure of zebrafish to 0, 5 and 50nM TBBPA during 1-120days post-fertilization (dpf) following by detoxification for four months before the behaviors assessment. These low concentration TBBPA exposures were not associated with malformations and did not alter sex ratio, but resulted in reduced zebrafish body weight and length. Adult behavioral assays indicated that TBBPA exposed males had significantly higher average swim speeds and spent significantly more time in high speed darting mode and less time in medium cruising mode compared to control males. In an adult photomotor response assay, TBBPA exposure was associated with hyperactivity in male fish. Female zebrafish responses in these assays followed a similar trend, but the magnitude of TBBPA effects was generally smaller than in males. Social interaction evaluated using a mirror attack test showed that 50nM TBBPA exposed males had heightened aggression. Females exposed to 50nM TBBPA spent more time in the vicinity of the mirror, but did not show increased aggression toward the mirror compared to unexposed control fish. Overall, the hyperactivity and social behavior deficits ascribed here to chronic TBBPA exposure was most profound in males. Our findings indicate that TBBPA can cause developmental and neurobehavioral deficits, and may pose significant health risk to humans. PMID:27221227

  2. Interaction of fatty acid genotype and diet on changes in colonic fatty acids in a Mediterranean diet intervention study.

    PubMed

    Porenta, Shannon R; Ko, Yi-An; Gruber, Stephen B; Mukherjee, Bhramar; Baylin, Ana; Ren, Jianwei; Djuric, Zora

    2013-11-01

    A Mediterranean diet increases intakes of n-3 and n-9 fatty acids and lowers intake of n-6 fatty acids. This can impact colon cancer risk as n-6 fatty acids are metabolized to proinflammatory eicosanoids. The purpose of this study was to evaluate interactions of polymorphisms in the fatty acid desaturase (FADS) genes, FADS1 and FADS2, and changes in diet on fatty acid concentrations in serum and colon. A total of 108 individuals at increased risk of colon cancer were randomized to either a Mediterranean or a Healthy Eating diet. Fatty acids were measured in both serum and colonic mucosa at baseline and after six months. Each individual was genotyped for four single-nucleotide polymorphisms in the FADS gene cluster. Linear regression was used to evaluate the effects of diet, genotype, and the diet by genotype interaction on fatty acid concentrations in serum and colon. Genetic variation in the FADS genes was strongly associated with baseline serum arachidonic acid (n-6) but serum eicosapentaenoic acid (n-3) and colonic fatty acid concentrations were not significantly associated with genotype. After intervention, there was a significant diet by genotype interaction for arachidonic acid concentrations in colon. Subjects who had all major alleles for FADS1/2 and were following a Mediterranean diet had 16% lower arachidonic acid concentrations in the colon after six months of intervention than subjects following the Healthy Eating diet. These results indicate that FADS genotype could modify the effects of changes in dietary fat intakes on arachidonic acid concentrations in the colon. PMID:24022589

  3. The interactive effects of climate change, riparian management, and a non-native predators on stream-rearing salmon

    USGS Publications Warehouse

    Lawrence, David J.; Stewart-Koster, Ben; Olden, Julian D.; Ruesch, Aaron S.; Torgersen, Christian E.; Lawler, Joshua J.; Butcher, Don P.; Crown, Julia K.

    2014-01-01

    Predicting how climate change is likely to interact with myriad other stressors that threaten species of conservation concern is an essential challenge in aquatic ecosystems. This study provides a framework to accomplish this task in salmon-bearing streams of the northwestern United States, where land-use related reductions in riparian shading have caused changes in stream thermal regimes, and additional warming from projected climate change may result in significant losses of coldwater fish habitat over the next century. Predatory non-native smallmouth bass have also been introduced into many northwestern streams and their range is likely to expand as streams warm, presenting an additional challenge to the persistence of threatened Pacific salmon. The goal of this work was to forecast the interactive effects of climate change, riparian management, and non-native species on stream-rearing salmon, and to evaluate the capacity of restoration to mitigate these effects. We intersected downscaled global climate forecasts with a local-scale water temperature model to predict mid- and end-of-century temperatures in streams in the Columbia River basin; we compared one stream that is thermally impaired due to the loss of riparian vegetation and another that is cooler and has a largely intact riparian corridor. Using the forecasted stream temperatures in conjunction with fish-habitat models, we predicted how stream-rearing Chinook salmon and bass distributions would change as each stream warmed. In the highly modified stream, end-of-century warming may cause near total loss of Chinook salmon rearing habitat and a complete invasion of the upper watershed by bass. In the less modified stream, bass were thermally restricted from the upstream-most areas. In both systems, temperature increases resulted in higher predicted spatial overlap between stream-rearing Chinook salmon and potentially predatory bass in the early summer (2-4-fold increase) and greater abundance of bass. We

  4. The interactive effects of climate change, riparian management, and a nonnative predator on stream-rearing salmon.

    PubMed

    Lawrence, David J; Stewart-Koster, Ben; Olden, Julian D; Ruesch, Aaron S; Torgersen, Christian E; Lawler, Joshua J; Butcher, Don P; Crown, Julia K

    2014-06-01

    Predicting how climate change is likely to interact with myriad other stressors that threaten species of conservation concern is an essential challenge in aquatic ecosystems. This study provides a framework to accomplish this task in salmon-bearing streams of the northwestern United States, where land-use-related reductions in riparian shading have caused changes in stream thermal regimes, and additional warming from projected climate change may result in significant losses of coldwater fish habitat over the next century. Predatory, nonnative smallmouth bass have also been introduced into many northwestern streams, and their range is likely to expand as streams warm, presenting an additional challenge to the persistence of threatened Pacific salmon. The goal of this work was to forecast the interactive effects of climate change, riparian management, and nonnative species on stream-rearing salmon and to evaluate the capacity of restoration to mitigate these effects. We intersected downscaled global climate forecasts with a local-scale water temperature model to predict mid- and end-of-century temperatures in streams in the Columbia River basin. We compared one stream that is thermally impaired due to the loss of riparian vegetation and another that is cooler and has a largely intact riparian corridor. Using the forecasted stream temperatures in conjunction with fish-habitat models, we predicted how stream-rearing chinook salmon and bass distributions would change as each stream warmed. In the highly modified stream, end-of-century warming may cause near total loss of chinook salmon-rearing habitat and a complete invasion of the upper watershed by bass. In the less modified stream, bass were thermally restricted from the upstream-most areas. In both systems, temperature increases resulted in higher predicted spatial overlap between stream-rearing chinook salmon and potentially predatory bass in the early summer (two- to fourfold increase) and greater abundance of

  5. Aerosol-halogen interaction: Change of physico-chemical properties of SOA by naturally released halogen species

    NASA Astrophysics Data System (ADS)

    Ofner, J.; Balzer, N.; Buxmann, J.; Grothe, H.; Krüger, H.; Platt, U.; Schmitt-Kopplin, P.; Zetzsch, C.

    2011-12-01

    Reactive halogen species are released by various sources like photo-activated sea-salt aerosol or salt pans and salt lakes. These heterogeneous release mechanisms have been overlooked so far, although their potential of interaction with organic aerosols like Secondary Organic Aerosol (SOA), Biomass Burning Organic Aerosol (BBOA) or Atmospheric Humic LIke Substances (HULIS) is completely unknown. Such reactions can constitute sources of gaseous organo-halogen compounds or halogenated organic particles in the atmospheric boundary layer. To study the interaction of organic aerosols with reactive halogen species (RHS), SOA was produced from α-pinene, catechol and guaiacol using an aerosol smog-chamber. The model SOAs were characterized in detail using a variety of physico-chemical methods (Ofner et al., 2011). Those aerosols were exposed to molecular halogens in the presence of UV/VIS irradiation and to halogens, released from simulated natural halogen sources like salt pans, in order to study the complex aerosol-halogen interaction. The heterogeneous reaction of RHS with those model aerosols leads to different gaseous species like CO2, CO and small reactive/toxic molecules like phosgene (COCl2). Hydrogen containing groups on the aerosol particles are destroyed to form HCl or HBr, and a significant formation of C-Br bonds could be verified in the particle phase. Carbonyl containing functional groups of the aerosol are strongly affected by the halogenation process. While changes of functional groups and gaseous species were visible using FTIR spectroscopy, optical properties were studied using Diffuse Reflectance UV/VIS spectroscopy. Overall, the optical properties of the processed organic aerosols are significantly changed. While chlorine causes a "bleaching" of the aerosol particles, bromine shifts the maximum of UV/VIS absorption to the red end of the UV/VIS spectrum. Further physico-chemical changes were recognized according to the aerosol size-distributions or the

  6. Changes of petrophysical properties of sandstones due to interaction with carbon dioxide, a laboratory study

    NASA Astrophysics Data System (ADS)

    Nover, Georg; von der Gönna, Jutta; Heikamp, Stephanie; Köster, Jens

    2013-04-01

    Changes of petrophysical, petrological, mineralogical, mechanical and chemical parameters were studied on sandstones from the Hessian depression and sandstones from Neidenbach (Eifel) before and after alteration with CO2. The experiments were performed in a wide pressure and temperature range (p >10<20 MPa; T > 100<200°C) to cover the pressure and temperature conditions of most promising deep saline aquifers, with the consequence that CO2 is above the critical point and thus in supercritical state (scCO2). The experiments lasted from 10 days up to more than 6 month. In repeated experiments samples were analyzed after every 2 up to 6 weeks reaction time. Experiments were performed in two different setups, i) the pore volume was fully saturated with a CO2-saturated artificial brine (3 M NaCl-solution) and ii) the pore volume was partially saturated with brine and in direct contact with wet CO2. Initial values of the untreated samples exhibit quartz to range from < 50% up to >85 weight %, density from 2.62 - 2.70 g/cm3, porosity from < 10% up to > 25% and permeability from < 10-17 up to 10-12 m². In both experimental setups porosity increased by less than 2 vol%. The increase in permeability was less than one order in magnitude for i) and more than 1.5 orders in magnitude for ii). The mineralogical composition was unchanged within the detection limit of powder X-Ray diffraction (XRD), while X-Ray Fluorescence Analysis (XRF) indicated mobilization of calcium, magnesium, aluminum and potassium. Dissolution was confirmed by the chemical analysis (ICP-OES-MS) of recovered artificial brines that showed an increase of the ionic species Ca, Mg, Al and K after the scCO2-experiments. Partial solution of feldspar and clay was detected by optical inspection and scanning electron microprobe SEM-analysis. Low frequency electrical conductivity experiments (SIP, spectral induced polarization) exhibited both, a significant increase in conductivity that could be explained by

  7. Ozone-induced changes in host-plant suitability: interactions of Keiferia lycopersicella and Lycopersicon esculentum

    SciTech Connect

    Trumble, J.T.; Hare, J.D.; Musselman, R.C.; McCool, P.M.

    1987-01-01

    Tomato pinworms, Keiferia lycopersicella (Walsingham), survived better and developed faster on tomato plants, Lycopersicon esculentum Mill., damaged by ozone than on plants not subjected to ozone fumigation. Other measures of fitness, including survival during pupation, sex ratio of adults, female longevity, and fecundity, were not affected. Analyses of ozonated foliage at zero, two and seven days following fumigation demonstrated a transient but significant increase (18-24%) in soluble protein concentration. Although the concentration of the total free amino acids in ozonated foliage did not increase significantly, significant changes were observed in at least 10 specific amino acids, some of which are critical for either insect development or the production of plant defensive chemicals. A reduction in total nitrogen in ozonated foliage at seven days postfumigation indicated that nitrogen was being translocated to other portions of the plant. The implications of increases in assimilable forms of nitrogen in ozonated foliage, which lead to improved host-plant suitability for insect herbivores, are discussed both in relation to some current ecological theories and in regard to pest-management strategies. 59 references, 1 figure, 4 tables.

  8. The Structural Changes of Tropical Cyclones Upon Interaction with Vertical Wind Shear

    NASA Technical Reports Server (NTRS)

    Ritchie, Elizabeth A.

    2003-01-01

    The Fourth Convection and Moisture Experiment (CAMEX-4) provided a unique opportunity to observe the distributions and document the roles of important atmospheric factors that impact the development of the core asymmetries and core structural changes of tropical cyclones embedded in vertical wind shear. The state-of-the-art instruments flown on the NASA DC-8 and ER-2, in addition to those on the NOAA aircraft, provided a unique set of observations that documented the core structure throughout the depth of the tropical cyclone. These data have been used to conduct a combined observational and modeling study using a state-of-the-art, high- resolution mesoscale model to examine the role of the environmental vertical wind shear in producing tropical cyclone core asymmetries, and the effects on the structure and intensity of tropical cyclones.The scientific objectives of this study were to obtain in situ measurements that would allow documentation of the physical mechanisms that influence the development of the asymmetric convection and its effect on the core structure of the tropical cyclone.

  9. Effects of solar UV radiation on aquatic ecosystems and interactions with climate change.

    PubMed

    Häder, D-P; Kumar, H D; Smith, R C; Worrest, R C

    2007-03-01

    Recent results continue to show the general consensus that ozone-related increases in UV-B radiation can negatively influence many aquatic species and aquatic ecosystems (e.g., lakes, rivers, marshes, oceans). Solar UV radiation penetrates to ecological significant depths in aquatic systems and can affect both marine and freshwater systems from major biomass producers (phytoplankton) to consumers (e.g., zooplankton, fish, etc.) higher in the food web. Many factors influence the depth of penetration of radiation into natural waters including dissolved organic compounds whose concentration and chemical composition are likely to be influenced by future climate and UV radiation variability. There is also considerable evidence that aquatic species utilize many mechanisms for photoprotection against excessive radiation. Often, these protective mechanisms pose conflicting selection pressures on species making UV radiation an additional stressor on the organism. It is at the ecosystem level where assessments of anthropogenic climate change and UV-related effects are interrelated and where much recent research has been directed. Several studies suggest that the influence of UV-B at the ecosystem level may be more pronounced on community and trophic level structure, and hence on subsequent biogeochemical cycles, than on biomass levels per se. PMID:17344962

  10. Evolution of natural and social science interactions in global change research programs

    PubMed Central

    Mooney, Harold A.; Duraiappah, Anantha; Larigauderie, Anne

    2013-01-01

    Efforts to develop a global understanding of the functioning of the Earth as a system began in the mid-1980s. This effort necessitated linking knowledge from both the physical and biological realms. A motivation for this development was the growing impact of humans on the Earth system and need to provide solutions, but the study of the social drivers and their consequences for the changes that were occurring was not incorporated into the Earth System Science movement, despite early attempts to do so. The impediments to integration were many, but they are gradually being overcome, which can be seen in many trends for assessments, such as the Intergovernmental Platform on Biodiversity and Ecosystem Services, as well as both basic and applied science programs. In this development, particular people and events have shaped the trajectories that have occurred. The lessons learned should be considered in such emerging research programs as Future Earth, the new global program for sustainability research. The transitioning process to this new program will take time as scientists adjust to new colleagues with different ideologies, methods, and tools and a new way of doing science. PMID:23297237

  11. Societal attitudes to girl child -- leading to abuse and infanticide. Innovative interaction for change.

    PubMed

    Kumarbabu, G

    1993-01-01

    Parents in certain castes in certain regions of India prefer to bear sons and kill their infant girls in the attempt to minimize household expenditures and maximize household income over the long term. This practice was widely prevalent at least as far back as when the British came to power in India. The Indian Council for Child Welfare entered Tamil Nadu in 1987 as a welfare organization with the primary objective of preventing female infanticide. From working initially in 10 villages, the organization's effort have expanded to encompass 246 villages. Day-care centers have been established for working women; workers reach out to encourage pregnant women to accept female babies and not kill them; and the small family norm is promoted. A women's group has been formed and efforts are being made to enroll girls in school, educate the older women, and encourage alternative income generating programs. Despite some signs of success from the program's efforts, the author notes the difficulty in finding qualified and willing workers. Gradual change is being observed in attitudes toward female offspring; it is hoped that the trend continues. PMID:12287370

  12. Environmental Changes in MoTe2 Excitonic Dynamics by Defects-Activated Molecular Interaction.

    PubMed

    Chen, Bin; Sahin, Hasan; Suslu, Aslihan; Ding, Laura; Bertoni, Mariana I; Peeters, F M; Tongay, Sefaattin

    2015-05-26

    Monolayers of group VI transition metal dichalcogenides possess direct gaps in the visible spectrum with the exception of MoTe2, where its gap is suitably located in the infrared region but its stability is of particular interest, as tellurium compounds are acutely sensitive to oxygen exposure. Here, our environmental (time-dependent) measurements reveal two distinct effects on MoTe2 monolayers: For weakly luminescent monolayers, photoluminescence signal and optical contrast disappear, as if they are decomposed, but yet remain intact as evidenced by AFM and Raman measurements. In contrast, strongly luminescent monolayers retain their optical contrast for a prolonged amount of time, while their PL peak blue-shifts and PL intensity saturates to slightly lower values. Our X-ray photoelectron spectroscopy measurements and DFT calculations suggest that the presence of defects and functionalization of these defect sites with O2 molecules strongly dictate their material properties and aging response by changing the excitonic dynamics due to deep or shallow states that are created within the optical band gap. Presented results not only shed light on environmental effects on fundamental material properties and excitonic dynamics of MoTe2 monolayers but also highlight striking material transformation for metastable 2D systems such as WTe2, silicone, and phosphorene. PMID:25868985

  13. Static stress changes and fault interactions in Lefkada Island, Western Greece

    NASA Astrophysics Data System (ADS)

    Mitsakaki, C.; Rondoyanni, Th.; Anastasiou, D.; Papazissi, K.; Marinou, A.; Sakellariou, M.

    2013-07-01

    The complicated tectonics of the Mediterranean region, dominated by the subduction of the African plate under Eurasia, affects the whole of Greece. A significant extension rate across the Aegean sea is estimated from satellite geodetic observations, while intense seismicity is observed in parts of the Hellenic arc, manifested by strong earthquakes (Ms > 6) of intermediate depth that take place along it. In Western Greece, the Ionian Islands are situated in a transitional zone (from the Hellenic subduction to the Adriatic collision), characterised by a high crustal deformation rate as revealed by the high seismicity of this zone, the highest in Greece, and the GPS velocity field estimated for the region. In this part of the Aegean plate, transcurrent fault systems dominate, one of which is the Kephalonia Transform Fault (KTF), located offshore the Kephalonia and Lefkada Islands, with a right-lateral slip of the order of 3 cm/year. In the present work an attempt is made to assess the Coulomb stress change associated with well documented earthquake activity, from 1973 to 2003, in the Ionian Island of Lefkada. The results of this study suggest that the early 1973 event did not influence any subsequent moderate earthquakes in the area. On the other hand, the 1994 earthquake may have triggered the north segment of the 2003 event, while the 2003 earthquake ruptured two segments with the north one initiating rupture on the south segment.

  14. Population Responses to Environmental Change in a Tropical Ant: The Interaction of Spatial and Temporal Dynamics

    PubMed Central

    Jackson, Doug; Vandermeer, John; Perfecto, Ivette; Philpott, Stacy M.

    2014-01-01

    Spatial structure can have a profound, but often underappreciated, effect on the temporal dynamics of ecosystems. Here we report on a counterintuitive increase in the population of a tree-nesting ant, Azteca sericeasur, in response to a drastic reduction in the number of potential nesting sites. This surprising result is comprehensible when viewed in the context of the self-organized spatial dynamics of the ants and their effect on the ants’ dispersal-limited natural enemies. Approximately 30% of the trees in the study site, a coffee agroecosystem in southern Mexico, were pruned or felled over a two-year period, and yet the abundance of the ant nests more than doubled over the seven-year study. Throughout the transition, the spatial distribution of the ants maintained a power-law distribution – a signal of spatial self organization – but the local clustering of the nests was reduced post-pruning. A cellular automata model incorporating the changed spatial structure of the ants and the resulting partial escape from antagonists reproduced the observed increase in abundance, highlighting how self-organized spatial dynamics can profoundly influence the responses of ecosystems to perturbations. PMID:24842117

  15. Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin.

    PubMed

    Roberts, James J; Fausch, Kurt D; Peterson, Douglas P; Hooten, Mevin B

    2013-05-01

    Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a ≥90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments <7 km long, and those at the lowest elevations, are at the highest risk of extirpation. Therefore, interactions of stochastic disturbances with fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these risks. PMID

  16. Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin

    USGS Publications Warehouse

    Roberts, James J.; Fausch, Kurt D.; Peterson, Douglas P.; Hooten, Mevin B.

    2013-01-01

    Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a greater than or equal to 90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments <7 km long, and those at the lowest elevations, are at the highest risk of extirpation. Therefore, interactions of stochastic disturbances with fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these

  17. The Quantum Nature of Drug-Receptor Interactions: Deuteration Changes Binding Affinities for Histamine Receptor Ligands

    PubMed Central

    Repič, Matej; Zakšek, Maja; Kotnik, Kristina; Fijan, Estera; Mavri, Janez

    2016-01-01

    In this article we report a combined experimental and computational study concerning the effects of deuteration on the binding of histamine and two other histaminergic agonists to 3H-tiotidine-labeled histamine H2 receptor in neonatal rat astrocytes. Binding affinities were measured by displacing radiolabeled tiotidine from H2 receptor binding sites present on cultured neonatal rat astrocytes. Quantum-chemical calculations were performed by employing the empirical quantization of nuclear motion within a cluster model of the receptor binding site extracted from the homology model of the entire H2 receptor. Structure of H2 receptor built by homology modelling is attached in the supporting information (S1 Table) Experiments clearly demonstrate that deuteration affects the binding by increasing the affinity for histamine and reducing it for 2-methylhistamine, while basically leaving it unchanged for 4-methylhistamine. Ab initio quantum-chemical calculations on the cluster system extracted from the homology H2 model along with the implicit quantization of the acidic N–H and O–H bonds demonstrate that these changes in the binding can be rationalized by the altered strength of the hydrogen bonding upon deuteration known as the Ubbelohde effect. Our computational analysis also reveals a new mechanism of histamine binding, which underlines an important role of Tyr250 residue. The present work is, to our best knowledge, the first study of nuclear quantum effects on ligand receptor binding. The ligand H/D substitution is relevant for therapy in the context of perdeuterated and thus more stable drugs that are expected to enter therapeutic practice in the near future. Moreover, presented approach may contribute towards understanding receptor activation, while a distant goal remains in silico discrimination between agonists and antagonists based on the receptor structure. PMID:27159606

  18. Visual Information Alone Changes Behavior and Physiology during Social Interactions in a Cichlid Fish (Astatotilapia burtoni)

    PubMed Central

    Chen, Chun-Chun; Fernald, Russell D.

    2011-01-01

    Social behavior can influence physiological systems dramatically yet the sensory cues responsible are not well understood. Behavior of male African cichlid fish, Astatotilapia burtoni, in their natural habitat suggests that visual cues from conspecifics contribute significantly to regulation of social behavior. Using a novel paradigm, we asked whether visual cues alone from a larger conspecific male could influence behavior, reproductive physiology and the physiological stress response of a smaller male. Here we show that just seeing a larger, threatening male through a clear barrier can suppress dominant behavior of a smaller male for up to 7 days. Smaller dominant males being “attacked” visually by larger dominant males through a clear barrier also showed physiological changes for up to 3 days, including up-regulation of reproductive- and stress-related gene expression levels and lowered plasma 11-ketotestesterone concentrations as compared to control animals. The smaller males modified their appearance to match that of non-dominant males when exposed to a larger male but they maintained a physiological phenotype similar to that of a dominant male. After 7 days, reproductive- and stress- related gene expression, circulating hormone levels, and gonad size in the smaller males showed no difference from the control group suggesting that the smaller male habituated to the visual intruder. However, the smaller male continued to display subordinate behaviors and assumed the appearance of a subordinate male for a full week despite his dominant male physiology. These data suggest that seeing a larger male alone can regulate the behavior of a smaller male but that ongoing reproductive inhibition depends on additional sensory cues. Perhaps, while experiencing visual social stressors, the smaller male uses an opportunistic strategy, acting like a subordinate male while maintaining the physiology of a dominant male. PMID:21633515

  19. The Quantum Nature of Drug-Receptor Interactions: Deuteration Changes Binding Affinities for Histamine Receptor Ligands.

    PubMed

    Kržan, Mojca; Vianello, Robert; Maršavelski, Aleksandra; Repič, Matej; Zakšek, Maja; Kotnik, Kristina; Fijan, Estera; Mavri, Janez

    2016-01-01

    In this article we report a combined experimental and computational study concerning the effects of deuteration on the binding of histamine and two other histaminergic agonists to 3H-tiotidine-labeled histamine H2 receptor in neonatal rat astrocytes. Binding affinities were measured by displacing radiolabeled tiotidine from H2 receptor binding sites present on cultured neonatal rat astrocytes. Quantum-chemical calculations were performed by employing the empirical quantization of nuclear motion within a cluster model of the receptor binding site extracted from the homology model of the entire H2 receptor. Structure of H2 receptor built by homology modelling is attached in the supporting information (S1 Table) Experiments clearly demonstrate that deuteration affects the binding by increasing the affinity for histamine and reducing it for 2-methylhistamine, while basically leaving it unchanged for 4-methylhistamine. Ab initio quantum-chemical calculations on the cluster system extracted from the homology H2 model along with the implicit quantization of the acidic N-H and O-H bonds demonstrate that these changes in the binding can be rationalized by the altered strength of the hydrogen bonding upon deuteration known as the Ubbelohde effect. Our computational analysis also reveals a new mechanism of histamine binding, which underlines an important role of Tyr250 residue. The present work is, to our best knowledge, the first study of nuclear quantum effects on ligand receptor binding. The ligand H/D substitution is relevant for therapy in the context of perdeuterated and thus more stable drugs that are expected to enter therapeutic practice in the near future. Moreover, presented approach may contribute towards understanding receptor activation, while a distant goal remains in silico discrimination between agonists and antagonists based on the receptor structure. PMID:27159606

  20. Stream-Groundwater Interaction Buffers Seasonal Changes in Urban Stream Water Quality

    NASA Astrophysics Data System (ADS)

    Ledford, S. H.; Lautz, L. K.

    2013-12-01

    increased to around 0.58 mg N/L, but were still lower than the connected reach, which averaged 0.88 mg N/L. Groundwater discharge rates were measured longitudinally along the creek during a constant rate Rhodamine WT injection and also confirmed qualitatively by longitudinal changes in stream sulfate and δ18O. The buffering capability of groundwater discharge in urban systems has implications for managers trying to mitigate the effects of urbanization on surface water.

  1. Development and Implementation of an Interactive Text Messaging Campaign to Support Behavior Change in a Childhood Obesity Randomized Controlled Trial.

    PubMed

    Price, Sarah; Ferisin, Stephanie; Sharifi, Mona; Steinberg, David; Bennett, Gary; Wolin, Kathleen Y; Horan, Christine; Koziol, Renata; Marshall, Richard; Taveras, Elsie M

    2015-01-01

    Text messaging is a promising means of intervening on an array of health issues among varied populations, but little has been published about the development of such interventions. The authors describe the development and implementation of an interactive text messaging campaign for parents to support behavior change among children in a childhood obesity randomized controlled trial. The authors invited 160 parents to participate in a text messaging intervention that provided behavior change support in conjunction with health coaching phone calls and mailed materials on behavioral goals. Throughout the 1-year intervention, the authors sent 1-2 text messages per week. The first asked how the child did with a target behavior the day before; parents who replied received an immediate feedback message tailored to their response. The second included a tip about how to work toward a behavioral goal. Baseline surveys indicate that text messaging is a common means of communication for parents, and many are willing to use text messaging to support behavior change for their child. Results at 1 year indicate a high level of engagement with the text messaging intervention, with nearly two thirds responding to 75% or more of the questions they were sent by text. PMID:25996181

  2. Cytoglobin ligand binding regulated by changing haem-co-ordination in response to intramolecular disulfide bond formation and lipid interaction.

    PubMed

    Beckerson, Penny; Wilson, Michael T; Svistunenko, Dimitri A; Reeder, Brandon J

    2015-01-01

    Cytoglobin (Cygb) is a hexa-co-ordinate haem protein from the globin superfamily with a physiological function that is unclear. We have previously reported that the haem co-ordination is changed in the presence of lipids, potentially transforming the redox properties of the protein and hence the function of Cygb in vivo. Recent research suggests that the protein can exist in a number of states depending on the integrity and position of disulfide bonds. In the present study, we show that the monomeric protein with an internal disulfide bond between the two cysteine residues Cys38 and Cys83, interacts with lipids to induce a change in haem co-ordination. The dimeric protein with intermolecular disulfide bonds and monomeric protein without an intramolecular disulfide bond does not exhibit these changes in haem co-ordination. Furthermore, monomeric Cygb with an intramolecular disulfide bond has significantly different properties, oxidizing lipid membranes and binding ligands more rapidly as compared with the other forms of the protein. The redox state of these cysteine residues in vivo is therefore highly significant and may be a mechanism to modulate the biochemical properties of the haem under conditions of stress. PMID:25327890

  3. Complex Genotype by Environment interactions and changing genetic architectures across thermal environments in the Australian field cricket, Teleogryllus oceanicus

    PubMed Central

    2011-01-01

    Background Biologists studying adaptation under sexual selection have spent considerable effort assessing the relative importance of two groups of models, which hinge on the idea that females gain indirect benefits via mate discrimination. These are the good genes and genetic compatibility models. Quantitative genetic studies have advanced our understanding of these models by enabling assessment of whether the genetic architectures underlying focal phenotypes are congruent with either model. In this context, good genes models require underlying additive genetic variance, while compatibility models require non-additive variance. Currently, we know very little about how the expression of genotypes comprised of distinct parental haplotypes, or how levels and types of genetic variance underlying key phenotypes, change across environments. Such knowledge is important, however, because genotype-environment interactions can have major implications on the potential for evolutionary responses to selection. Results We used a full diallel breeding design to screen for complex genotype-environment interactions, and genetic architectures underlying key morphological traits, across two thermal environments (the lab standard 27°C, and the cooler 23°C) in the Australian field cricket, Teleogryllus oceanicus. In males, complex three-way interactions between sire and dam parental haplotypes and the rearing environment accounted for up to 23 per cent of the scaled phenotypic variance in the traits we measured (body mass, pronotum width and testes mass), and each trait harboured significant additive genetic variance in the standard temperature (27°C) only. In females, these three-way interactions were less important, with interactions between the paternal haplotype and rearing environment accounting for about ten per cent of the phenotypic variance (in body mass, pronotum width and ovary mass). Of the female traits measured, only ovary mass for crickets reared at the cooler

  4. Changes in flexibility upon binding: Application of the self-consistent pair contact probability method to protein-protein interactions

    NASA Astrophysics Data System (ADS)

    Canino, Lawrence S.; Shen, Tongye; McCammon, J. Andrew

    2002-12-01

    We extend the self-consistent pair contact probability method to the evaluation of the partition function for a protein complex at thermodynamic equilibrium. Specifically, we adapt the method for multichain models and introduce a parametrization for amino acid-specific pairwise interactions. This method is similar to the Gaussian network model but allows for the adjusting of the strengths of native state contacts. The method is first validated on a high resolution x-ray crystal structure of bovine Pancreatic Phospholipase A2 by comparing calculated B-factors with reported values. We then examine binding-induced changes in flexibility in protein-protein complexes, comparing computed results with those obtained from x-ray crystal structures and molecular dynamics simulations. In particular, we focus on the mouse acetylcholinesterase:fasciculin II and the human α-thrombin:thrombomodulin complexes.

  5. Interactive effects of elevated CO2 and precipitation change on leaf nitrogen of dominant Stipa L. species

    PubMed Central

    Shi, Yaohui; Zhou, Guangsheng; Jiang, Yanling; Wang, Hui; Xu, Zhenzhu; Song, Jian

    2015-01-01

    Nitrogen (N) serves as an important mineral element affecting plant productivity and nutritional quality. However, few studies have addressed the interactive effects of elevated CO2 and precipitation change on leaf N of dominant grassland genera such as Stipa L. This has restricted our understanding of the responses of grassland to climate change. We simulated the interactive effects of elevated CO2 concentration and varied precipitation on leaf N concentration (Nmass) of four Stipa species (Stipa baicalensis, Stipa bungeana, Stipa grandis, and Stipa breviflora; the most dominant species in arid and semiarid grassland) using open-top chambers (OTCs). The relationship between the Nmass of these four Stipa species and precipitation well fits a logarithmic function. The sensitivity of these four species to precipitation change was ranked as follows: S. bungeana > S. breviflora > S. baicalensis > S. grandis. The Nmass of S. bungeana was the most sensitive to precipitation change, while S. grandis was the least sensitive among these Stipa species. Elevated CO2 exacerbated the effect of precipitation on Nmass. Nmass decreased under elevated CO2 due to growth dilution and a direct negative effect on N assimilation. Elevated CO2 reduced Nmass only in a certain precipitation range for S. baicalensis (163–343 mm), S. bungeana (164–355 mm), S. grandis (148–286 mm), and S. breviflora (130–316 mm); severe drought or excessive rainfall would be expected to result in a reduced impact of elevated CO2. Elevated CO2 affected the Nmass of S. grandis only in a narrow precipitation range. The effect of elevated CO2 reached a maximum when the amount of precipitation was 253, 260, 217, and 222 mm for S. baicalensis, S. bungeana, S. grandis, and S. breviflora, respectively. The Nmass of S. grandis was the least sensitive to elevated CO2. The Nmass of S. breviflora was more sensitive to elevated CO2 under a drought condition compared with the other Stipa

  6. Interactive effects of elevated CO2 and precipitation change on leaf nitrogen of dominant Stipa L. species.

    PubMed

    Shi, Yaohui; Zhou, Guangsheng; Jiang, Yanling; Wang, Hui; Xu, Zhenzhu; Song, Jian

    2015-07-01

    Nitrogen (N) serves as an important mineral element affecting plant productivity and nutritional quality. However, few studies have addressed the interactive effects of elevated CO2 and precipitation change on leaf N of dominant grassland genera such as Stipa L. This has restricted our understanding of the responses of grassland to climate change. We simulated the interactive effects of elevated CO2 concentration and varied precipitation on leaf N concentration (Nmass) of four Stipa species (Stipa baicalensis, Stipa bungeana, Stipa grandis, and Stipa breviflora; the most dominant species in arid and semiarid grassland) using open-top chambers (OTCs). The relationship between the Nmass of these four Stipa species and precipitation well fits a logarithmic function. The sensitivity of these four species to precipitation change was ranked as follows: S. bungeana > S. breviflora > S. baicalensis > S. grandis. The Nmass of S. bungeana was the most sensitive to precipitation change, while S. grandis was the least sensitive among these Stipa species. Elevated CO2 exacerbated the effect of precipitation on Nmass. Nmass decreased under elevated CO2 due to growth dilution and a direct negative effect on N assimilation. Elevated CO2 reduced Nmass only in a certain precipitation range for S. baicalensis (163-343 mm), S. bungeana (164-355 mm), S. grandis (148-286 mm), and S. breviflora (130-316 mm); severe drought or excessive rainfall would be expected to result in a reduced impact of elevated CO2. Elevated CO2 affected the Nmass of S. grandis only in a narrow precipitation range. The effect of elevated CO2 reached a maximum when the amount of precipitation was 253, 260, 217, and 222 mm for S. baicalensis, S. bungeana, S. grandis, and S. breviflora, respectively. The Nmass of S. grandis was the least sensitive to elevated CO2. The Nmass of S. breviflora was more sensitive to elevated CO2 under a drought condition compared with the other Stipa species

  7. A frequent kinase domain mutation that changes the interaction between PI3K[alpha] and the membrane

    SciTech Connect

    Mandelker, Diana; Gabelli, Sandra B.; Schmidt-Kittler, Oleg; Zhu, Jiuxiang; Cheong, Ian; Huang, Chuan-Hsiang; Kinzler, Kenneth W.; Vogelstein, Bert; Amzel, L. Mario

    2009-12-01

    Mutations in oncogenes often promote tumorigenesis by changing the conformation of the encoded proteins, thereby altering enzymatic activity. The PIK3CA oncogene, which encodes p110{alpha}, the catalytic subunit of phosphatidylinositol 3-kinase alpha (PI3K{alpha}), is one of the two most frequently mutated oncogenes in human cancers. We report the structure of the most common mutant of p110{alpha} in complex with two interacting domains of its regulatory partner (p85{alpha}), both free and bound to an inhibitor (wortmannin). The N-terminal SH2 (nSH2) domain of p85{alpha} is shown to form a scaffold for the entire enzyme complex, strategically positioned to communicate extrinsic signals from phosphopeptides to three distinct regions of p110{alpha}. Moreover, we found that Arg-1047 points toward the cell membrane, perpendicular to the orientation of His-1047 in the WT enzyme. Surprisingly, two loops of the kinase domain that contact the cell membrane shift conformation in the oncogenic mutant. Biochemical assays revealed that the enzymatic activity of the p110{alpha} His1047Arg mutant is differentially regulated by lipid membrane composition. These structural and biochemical data suggest a previously undescribed mechanism for mutational activation of a kinase that involves perturbation of its interaction with the cellular membrane.

  8. Lipid composition and molecular interactions change with depth in the avian stratum corneum to regulate cutaneous water loss.

    PubMed

    Champagne, Alex M; Allen, Heather C; Williams, Joseph B

    2015-10-01

    The outermost 10-20 µm of the epidermis, the stratum corneum (SC), consists of flat, dead cells embedded in a matrix of intercellular lipids. These lipids regulate cutaneous water loss (CWL), which accounts for over half of total water loss in birds. However, the mechanisms by which lipids are able to regulate CWL and how these mechanisms change with depth in the SC are poorly understood. We used attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to measure lipid-lipid and lipid-water interactions as a function of depth in the SC of house sparrows (Passer domesticus Linnaeus) in the winter and summer. We then compared these molecular interactions at each depth with lipid composition at the same depth. We found that in both groups, water content increased with depth in the SC, and likely contributed to greater numbers of gauche defects in lipids in deeper levels of the SC. In winter-caught birds, which had lower rates of CWL than summer-caught birds, water exhibited stronger hydrogen bonding in deeper layers of the SC, and these strong hydrogen bonds were associated with greater amounts of polar lipids such as ceramides and cerebrosides. Based on these data, we propose a model by which polar lipids in deep levels of the SC form strong hydrogen bonds with water molecules to increase the viscosity of water and slow the permeation of water through the SC. PMID:26447196

  9. Climate Change and Tritrophic Interactions: Will Modifications to Greenhouse Gas Emissions Increase the Vulnerability of Herbivorous Insects to Natural Enemies?

    PubMed

    Boullis, Antoine; Francis, Frederic; Verheggen, François J

    2015-04-01

    Insects are highly dependent on odor cues released into the environment to locate conspecifics or food sources. This mechanism is particularly important for insect predators that rely on kairomones released by their prey to detect them. In the context of climate change and, more specifically, modifications in the gas composition of the atmosphere, chemical communication-mediating interactions between phytophagous insect pests, their host plants, and their natural enemies is likely to be impacted. Several reports have indicated that modifications to plants caused by elevated carbon dioxide and ozone concentrations might indirectly affect insect herbivores, with community-level modifications to this group potentially having an indirect influence on higher trophic levels. The vulnerability of agricultural insect pests toward their natural enemies under elevated greenhouse gases concentrations has been frequently reported, but conflicting results have been obtained. This literature review shows that the higher levels of carbon dioxide, as predicted for the coming century, do not enhance the abundance or efficiency of natural enemies to locate hosts or prey in most published studies. Increased ozone levels lead to modifications in herbivore-induced volatile organic compounds (VOCs) released by damaged plants, which may impact the attractiveness of these herbivores to the third trophic level. Furthermore, other oxidative gases (such as SO2 and NO2) tend to reduce the abundance of natural enemies. The impact of changes in atmospheric gas emissions on plant-insect and insect-insect chemical communication has been under-documented, despite the significance of these mechanisms in tritrophic interactions. We conclude by suggesting some further prospects on this topic of research yet to be investigated. PMID:26313181

  10. Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios

    NASA Astrophysics Data System (ADS)

    Glotfelty, Timothy; Zhang, Yang; Karamchandani, Prakash; Streets, David G.

    2016-08-01

    The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O3 level and of 0.3 μg m-3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO2, H2O2, and the nitrate radical and increasing the atmosphere's near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O3, and increases in CH4 and VOCs. Increasing NOx and O3 levels enhances the nitrogen and O3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth's surface with a global average reduction in shortwave radiation of 1.2 W m-2. This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR's CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed

  11. BOREAS (Boreal Ecosystem-Atmosphere Study): Global change and biosphere-atmosphere interactions in the boreal forest

    NASA Technical Reports Server (NTRS)

    Sellers, Piers J.

    1991-01-01

    The Boreal Ecosystems Atmosphere Study (BOREAS) is a cooperative field and analysis project involving elements of land surface climatology, tropospheric chemistry, and terrestrial ecology. The goal of the study is to understand the interactions between the boreal forest biome and the atmosphere in order to clarify their roles in global change. The study will be centered on two 20 by 20 km sites within the North American boreal forest region, located near the northern and southern limits of the biome. Studies based at these sites will be used to explore the roles of various environmental factors in controlling the extent and character of the biome. The sites will be the subject of surface, airborne, and satellite based observations which aim to improve understanding of the biological and physical processes and states which govern the exchanges of energy, water, carbon, and trace gases between boreal forest ecosystems and the atmosphere. Particular reference will be made to those processes and states that may be sensitive to global change. The study also aims to develop the use of remote sensing techniques to transfer understanding of the above process from local scales out to regional scales. The BOREAS project is being planned for 1992-1996, with a major field effort in 1994.

  12. Overcoming scepticism: Interacting influences of geographical location on perceived climate change adaptation measures to water resources in Spain

    NASA Astrophysics Data System (ADS)

    Iglesias, Ana; Garrote, Luis; Bardaji, Isabel; Iglesias, Pedro; Granados, Alfredo

    2016-04-01

    Though many climate adaptation efforts attempt to be defined with the participation of local communities, these strategies may be ineffective because among citizens affected equally, a local risk perception rather than scientific understanding largely drives adaptation choices. Further, the geographical location may polarize climate risk perceptions, making some adaptation efforts ineffective among sceptics. This study examines how the local degradation of the environment and water resources relates to adaption choices and in turn, climate change risk perception among a range of citizens in the Tagus basin, Spain (n = 300). We find respondents of less degraded areas have individualistic responses, and are significantly less likely to accept adaptation strategies than respondents in water stressed communities. The interaction between climate knowledge and adaptation choices is positively related to acceptance of adaptation choices in both groups, and had a stronger positive relationship among individualists. There is no statistical difference in acceptance of adaptation between individualists and communitarians at high levels of knowledge (top decile). Thus, education efforts specific to climate change may counteract divisions based geographical location and environmental stress.

  13. Global and regional effects of land-use change on climate in 21st century simulations with interactive carbon cycle

    NASA Astrophysics Data System (ADS)

    Boysen, L. R.; Brovkin, V.; Arora, V. K.; Cadule, P.; de Noblet-Ducoudré, N.; Kato, E.; Pongratz, J.; Gayler, V.

    2014-04-01

    Biogeophysical (BGP) and biogeochemical (BGC) effects of land-use and land cover change (LULCC) are separated at the global and regional scales in new interactive CO2 simulations for the 21st century. Results from four Earth System models (ESMs) are analyzed for the future RCP8.5 scenario from simulations with and without land-use and land cover change (LULCC) contributing to the Land-Use and Climate, IDentification of robust impacts (LUCID) project. Over the period, 2006-2100, LULCC causes the atmospheric CO2 concentration to increase by 12, 22, and 66 ppm in CanESM2, MIROC-ESM, and MPI-ESM-LR, respectively. Statistically significant changes in global near-surface temperature are found in three models with a BGC-induced global mean annual warming between 0.07 and 0.23 K. BGP-induced responses are simulated by three models in areas of intense LULCC of varying sign and magnitude (between -0.47 and 0.10 K). Global land carbon losses due to LULCC are simulated by all models: 218, 57, 35 and 34 Gt C by MPI-ESM-LR, MIROC-ESM, IPSL-CM5A-LR and CanESM2, respectively. On the contrary, the CO2-fertilization effect caused by elevated atmospheric CO2 concentrations due to LULCC leads to a land carbon gain of 39 Gt C in MPI-ESM-LR and is almost negligible in the other models. A substantial part of the spread in models' responses to LULCC is attributed to the differences in implementation of LULCC (e.g. whether pastures or crops are simulated explicitly) and the simulation of specific processes. Simple idealized experiments with clear protocols for implementing LULCC in ESMs are needed to increase the understanding of model responses and the statistical significance of results, especially, when analyzing the regional-scale impacts of LULCC.

  14. Changes.

    ERIC Educational Resources Information Center

    Weikel, William J.

    1999-01-01

    The author, founding editor of the American Mental Health Counselors Association (AMHC) Journal, now the Journal of Mental Health Counseling, examines some of the changes that have taken place in the profession over the past 20 years. Special emphasis is given to the visionary excellence that set the "AMHCA Agenda" over 20 years ago. (Author)

  15. Coral and algal changes after the 1998 coral bleaching: interaction with reef management and herbivores on Kenyan reefs

    NASA Astrophysics Data System (ADS)

    McClanahan, T.; Muthiga, N.; Mangi, S.

    2001-05-01

    Interaction between the El Niño and Indian Ocean dipole ocean-atmosphere quasi-periodic oscillations produced one of the warmest seawater temperatures on record in 1998. During the warm northeast monsoon in March and April, Kenya's shallow coral reefs experienced water temperatures between 30 and 31 °C and low winds. This caused large-scale bleaching of hard and soft corals at the end of March, which extended into the cooler months of May and June. Direct observations of coloration in the Mombasa Marine National Park found that the coral genera Acropora, Millepora, Pocillopora, branching Porites and Stylophora showed rapid bleaching and high mortality by the end of May 1998. Other hard coral genera that bleached significantly included Echinopora, Favia, Favites, Galaxea, Hydnophora, Goniopora, Leptoria, Montipora, Platygyra and massive Porites, but mortality was variable among these genera. Astreopora, Coscinarea, Cyphastrea and Pavona were the least responsive genera, with some paling, but little evidence of full bleaching or significant mortality. We compared changes in reef ecology in four national parks (protected from fishing) with four non-park areas (heavy fishing) to determine how coral mortality and herbivory interact under the two management regimes. Benthic studies using line transects in 16 sites spread across ~150 km of coastline were completed before and 6 to 13 months after the bleaching event and found that the cover of nine hard coral genera including Acropora, Alveopora, Favites, Goniopora, Platygyra, Pocillopora, branching Porites, Stylophora and Tubipora decreased significantly ( p<0.04) after the event, usually by >85%, and soft coral cover decreased by ~75%. One year after the bleaching, sites in the national parks experienced 88 and 115% increases in turf and fleshy algal cover, respectively, while reefs outside the parks had a 220% increase in fleshy algal cover with no appreciable change in turf-forming algal cover. There was, however

  16. Fully coupled ice sheet-earth system model: How does the Greenlandic ice sheet interact in a changing climate

    NASA Astrophysics Data System (ADS)

    Rodehacke, C.; Mikolajewicz, U.; Vizcaino, M.

    2012-04-01

    As ice sheets belong to the slowest climate components, they are usually not interactively coupled in current climate models. Therefore, long-term climate projections are incomplete and only the consideration of ice sheet interactions allows tackling fundamental questions, such as how do ice sheets modify the reaction of the climate systems under a strong CO2 forcing? The earth system model MPI-ESM, with the atmosphere model ECHAM6 and ocean model MPIOM, is coupled to the modified ice sheet model PISM. This ice sheet model, which is developed at the University of Fairbanks, represents the ice sheet of Greenland at a horizontal resolution of 10 km. The coupling is performed by calculating the surface mass balance based on 6-hourly atmospheric data to determine the boundary condition for the ice sheet model. The response of the ice sheet to this forcing, which includes orographic changes and fresh water fluxes, are passed back to the ESM. In contrast to commonly used strategies, we use a mass conserving scheme and do therefore neither apply flux corrections nor utilize anomaly coupling. Under a strong CO2 forcing a disintegrating Greenlandic ice sheet contributes to a rising sea level and has the potential to alter the formation of deep water masses in the adjacent formation sites Labrador Sea and Nordic Seas. We will present results for an idealized forcing with a growing atmospheric CO2 concentration that rises by 1% per year until four-times the pre-industrial level has been reached. We will discuss the reaction of the ice sheet and immediate responses of the ocean to ice loss.

  17. In silico functional dissection of saturation mutagenesis: Interpreting the relationship between phenotypes and changes in protein stability, interactions and activity

    PubMed Central

    Pires, Douglas E. V.; Chen, Jing; Blundell, Tom L.; Ascher, David B.

    2016-01-01

    Despite interest in associating polymorphisms with clinical or experimental phenotypes, functional interpretation of mutation data has lagged behind generation of data from modern high-throughput techniques and the accurate prediction of the molecular impact of a mutation remains a non-trivial task. We present here an integrated knowledge-driven computational workflow designed to evaluate the effects of experimental and disease missense mutations on protein structure and interactions. We exemplify its application with analyses of saturation mutagenesis of DBR1 and Gal4 and show that the experimental phenotypes for over 80% of the mutations correlate well with predicted effects of mutations on protein stability and RNA binding affinity. We also show that analysis of mutations in VHL using our workflow provides valuable insights into the effects of mutations, and their links to the risk of developing renal carcinoma. Taken together the analyses of the three examples demonstrate that structural bioinformatics tools, when applied in a systematic, integrated way, can rapidly analyse a given system to provide a powerful approach for predicting structural and functional effects of thousands of mutations in order to reveal molecular mechanisms leading to a phenotype. Missense or non-synonymous mutations are nucleotide substitutions that alter the amino acid sequence of a protein. Their effects can range from modifying transcription, translation, processing and splicing, localization, changing stability of the protein, altering its dynamics or interactions with other proteins, nucleic acids and ligands, including small molecules and metal ions. The advent of high-throughput techniques including sequencing and saturation mutagenesis has provided large amounts of phenotypic data linked to mutations. However, one of the hurdles has been understanding and quantifying the effects of a particular mutation, and how they translate into a given phenotype. One approach to overcome

  18. Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

    NASA Astrophysics Data System (ADS)

    Churkina, G.; Zaehle, S.; Hughes, J.; Viovy, N.; Chen, Y.; Jung, M.; Heumann, B. W.; Ramankutty, N.; Rödenbeck, C.; Heimann, M.; Jones, C.

    2010-03-01

    European ecosystems are thought to uptake significant amounts of carbon, but neither the rate nor the contributions of the underlying processes are well known. In the second half of the 20th century, carbon dioxide concentrations have risen by more than 100 ppm, atmospheric nitrogen deposition has more than doubled, and European mean temperatures were increasing by 0.02 °C per year. The extents of forest and grasslands have increase with the respective rates of 5800 km2 yr-1 and 1100 km2 yr-1 as agricultural land has been abandoned at a rate of 7000 km2 yr-1. In this study, we analyze the responses of European land ecosystems to the aforementioned environmental changes using results from four process-based ecosystem models: BIOME-BGC, JULES, ORCHIDEE, and O-CN. All four models suggest that European terrestrial ecosystems sequester carbon at a rate of 100 TgC yr-1 (1980-2007 mean) with strong interannual variability (± 85 TgC yr-1) and a substantial inter-model uncertainty (± 45 TgC yr-1). Decadal budgets suggest that there has been a slight increase in terrestrial net carbon storage from 85 TgC yr-1 in 1980-1989 to 114 TgC yr-1 in 2000-2007. The physiological effect of rising CO2 in combination with nitrogen deposition and forest re-growth have been identified as the important explanatory factors for this net carbon storage. Changes in the growth of woody vegetation are an important contributor to the European carbon sink. Simulated ecosystem responses were more consistent for the two models accounting for terrestrial carbon-nitrogen dynamics than for the two models which only accounted for carbon cycling and the effects of land cover change. Studies of the interactions of carbon-nitrogen dynamics with land use changes are needed to further improve the quantitative understanding of the driving forces of the European land carbon balance.

  19. Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

    NASA Astrophysics Data System (ADS)

    Churkina, G.; Zaehle, S.; Hughes, J.; Viovy, N.; Chen, Y.; Jung, M.; Heumann, B. W.; Ramankutty, N.; Heimann, M.; Jones, C.

    2010-09-01

    European ecosystems are thought to take up large amounts of carbon, but neither the rate nor the contributions of the underlying processes are well known. In the second half of the 20th century, carbon dioxide concentrations have risen by more that 100 ppm, atmospheric nitrogen deposition has more than doubled, and European mean temperatures were increasing by 0.02 °C yr-1. The extents of forest and grasslands have increased with the respective rates of 5800 km2 yr-1 and 1100 km2 yr-1 as agricultural land has been abandoned at a rate of 7000 km2 yr-1. In this study, we analyze the responses of European land ecosystems to the aforementioned environmental changes using results from four process-based ecosystem models: BIOME-BGC, JULES, ORCHIDEE, and O-CN. The models suggest that European ecosystems sequester carbon at a rate of 56 TgC yr-1 (mean of four models for 1951-2000) with strong interannual variability (±88 TgC yr-1, average across models) and substantial inter-model uncertainty (±39 TgC yr-1). Decadal budgets suggest that there has been a continuous increase in the mean net carbon storage of ecosystems from 85 TgC yr-1 in 1980s to 108 TgC yr-1 in 1990s, and to 114 TgC yr-1 in 2000-2007. The physiological effect of rising CO2 in combination with nitrogen deposition and forest re-growth have been identified as the important explanatory factors for this net carbon storage. Changes in the growth of woody vegetation are suggested as an important contributor to the European carbon sink. Simulated ecosystem responses were more consistent for the two models accounting for terrestrial carbon-nitrogen dynamics than for the two models which only accounted for carbon cycling and the effects of land cover change. Studies of the interactions of carbon-nitrogen dynamics with land use changes are needed to further improve the quantitative understanding of the driving forces of the European land carbon balance.

  20. Land-atmosphere interactions in a changing climate: An overview of the GLACE-CMIP5 experiment

    NASA Astrophysics Data System (ADS)

    Seneviratne, S. I.; Wilhelm, M.; Stanelle, T.; Hurk, B. V. D.; Hagemann, S.; Berg, A. M.; Cheruy, F.; Higgins, M.; Lorenz, R.; Meier, A.; Brovkin, V.; Claussen, M.; Ducharne, A.; Dufresne, J. L.; Findell, K. L.; Ghattas, J.; Lawrence, D. M.; Malyshev, S.; Pitman, A. J.; Rummukainen, M.; Smith, B.

    2014-12-01

    The Global Land-Atmosphere Climate Experiment-Coupled Model Intercomparison Project phase 5 (GLACE-CMIP5) is a multimodel experiment investigating the impact of soil moisture-climate feedbacks in CMIP5 simulations (Seneviratne et al. 2013). This experiment builds upon previous studies investigating the role of soil moisture-atmosphere interactions for seasonal forecasting (Koster et al. 2004) and for regional climate projections (Seneviratne et al. 2006). A total of 6 modeling groups took part in the experiment (CESM, EC-EARTH, GFDL, IPSL, MPI-ESM, and more recently ACCESS). The results reveal that projected soil moisture changes by the end of the 21st century substantially impact climate in several regions on both hemispheres, both under present and future climate conditions. Strong and consistent effects are found on temperature, especially for extremes (about 1- 1.5K for mean temperature and 2- 2.5K for extreme daytime temperature). In the Northern Hemisphere, effects on mean and heavy precipitation are also found in most models, but the results are less consistent than for temperature. A direct scaling between soil moisture induced changes in evaporative cooling and resulting changes in temperature mean and extremes is found in the simulations. Further results from more recent analyses, especially regarding impacts on extremes will be discussed. The presentation will also address the implications of these results for climate extremes attribution and climate change adaptation, as well as follow-up activities under CMIP6. References: Koster, R.D., et al., 2004: Science, 305, 1138-1140. Koster, R.D., et al., 2010: Geophys. Res. Lett., 37, L02402, doi:10.1029/2009GL041677. Seneviratne, S.I., D. Lüthi, M. Litschi, and C. Schär, 2006: Nature, 443, 205-209.Seneviratne, S.I., M. Wilhelm, T. Stanelle, B.J.J.M. van den Hurk, S. Hagemann, A. Berg, F. Cheruy, M.E. Higgins, A. Meier, V. Brovkin, M. Claussen, A. Ducharne, J.-L. Dufresne, K.L. Findell, J. Ghattas, D

  1. The Water Balance Portal in Saxony - An interactive web application concerning the impact of climate change on the water balance

    NASA Astrophysics Data System (ADS)

    Hauffe, Corina; Schwarze, Robert; Röhm, Patric; Müller, Ruben; Dröge, Werner; Gurova, Anastasia; Winkler, Peter; Baldy, Agnes

    2016-04-01

    Changes in weather and climate lead to increasing discussions about reasons and possible future impacts on the hydrological cycle. The question of a changed distribution of water also concerns the federal state of Saxony in the eastern part of Germany. Especially with a look at the different and increased requirements for water authorities, water economy and the public. To define and prepare these future requirements estimations of the future development of the natural water resources are necessary. Therefore data, information, and forecast concerning the development of the several components of the water balance are needed. And to make the obtained information easily available for experts and the public, tools like the internet have to be used. Under these frame conditions the water balance portal Saxony (www.wasserhaushaltsportal.sachsen.de) was developed within the project KliWES. The overall approach of the project was devided into the so-called „3 pillars".The first pillar focused on the evaluation of the status quo water balance from 1951-2005 by using a complex area-wide analysis of measured data. Also it contained the generating of a database and the development of a physically based parameter model. Furthermore an extensive model evaluation has been conducted with a number of objective assessment criteria, to select an appropriate model for the project. The second pillar included the calibration of the water balance model and the impact study of climate and land use change (1961-2100) on the water balance of Saxonian catchments. In this context 13 climate scenarios and three land use scenarios were simulated. The web presence of these two pillars represents a classical information service, which provides finalized results at the spatial resolution of sub-catchments using GIS-based webpages. The third pillar focused on the development of an interactive expert system. It allows the user (public, officials and consulting engineers) to simulate the water

  2. Cytochrome-P450-Cytochrome-b5 Interaction in a Membrane Environment Changes 15N Chemical Shift Anisotropy Tensors

    PubMed Central

    Pandey, Manoj Kumar; Vivekanandan, Subramanian; Ahuja, Shivani; Huang, Rui; Im, Sang-Choul; Waskell, Lucy; Ramamoorthy, Ayyalusamy

    2013-01-01

    It has been well realized that the dependence of chemical shift anisotropy (CSA) tensors on the amino acid sequence, secondary structure, dynamics and electrostatic interactions can be utilized in the structural and dynamic studies of proteins by NMR spectroscopy. In addition, CSA tensors could also be utilized to measure the structural interactions between proteins in a protein-protein complex. To this end, here we report the experimentally measured backbone amide-15N CSA tensors for a membrane-bound 16.7-kDa full-length rabbit cytochrome-b5 (cytb5), in complexation with a 55.8-kDa microsomal rabbit cytochrome P450 2B4 (cytP4502B4). The 15N-CSAs, determined using the 15N CSA/15N-1H dipolar coupling transverse cross-correlated rates, for free cytb5 are compared with that for the cytb5 bound to cytP4502B4. An overall increase in backbone amide-15N transverse cross-correlated rates for the cytb5 residues in the cytb5-cytP450 complex was observed as compared to the free cytb5 residues. Due to fast spin-spin relaxation (T2) and subsequent broadening of the signals in the complex, we were able to measure amide-15N CSAs only for 48 residues of cytb5 as compared to 84 residues of free cytb5. We observed a change in 15N CSA for most residues of cytb5 in the complex, when compared to free cytb5, suggesting a dynamic interaction between the oppositely charged surfaces of anionic cytb5 and cationic cytP450. The mean values of 15N CSA determined for residues in helical, sheet and turn regions of cytb5 in the complex are −184.5, −146.8, and −146.2 ppm, respectively, with an overall average value of −165.5 ppm (excluding the values from residues in more flexible termini). The measured CSA value for residues in helical conformation is slightly larger as compared to previously reported values. This may be attributed to the paramagnetic effect from Fe(III) of the heme in cytb5, which is similar to our previously reported values for the free cytb5. PMID:24107224

  3. Macromolecular Crowding Effects on Two Homologs of Ribosomal Protein S16: Protein-Dependent Structural Changes and Local Interactions

    PubMed Central

    Mikaelsson, Therese; Ådén, Jörgen; Wittung-Stafshede, Pernilla; Johansson, Lennart B.-Å.

    2014-01-01

    Proteins function in cellular environments that are crowded with biomolecules, and in this reduced available space, their biophysical properties may differ from those observed in dilute solutions in vitro. Here, we investigated the effects of a synthetic macromolecular crowding agent, dextran 20, on the folded states of hyperthermophilic (S16Thermo) and mesophilic (S16Meso) homologs of the ribosomal protein S16. As expected for an excluded-volume effect, the resistance of the mesophilic protein to heat-induced unfolding increased in the presence of dextran 20, and chemical denaturation experiments at different fixed temperatures showed the macromolecular crowding effect to be temperature-independent. Förster resonance energy transfer experiments show that intramolecular distances between an intrinsic Trp residue and BODIPY-labeled S16Meso depend on the level of the crowding agent. The BODIPY group was attached at three specific positions in S16Meso, allowing measurements of three intraprotein distances. All S16Meso variants exhibited a decrease in the average Trp-BODIPY distance at up to 100 mg/mL dextran 20, whereas the changes in distance became anisotropic (one distance increased, two distances decreased) at higher dextran concentrations. In contrast, the two S16Thermo mutants did not show any changes in Trp-BODIPY distances upon increase of dextran 20 concentrations. It should be noted that the fluorescence quantum yields and lifetimes of BODIPY attached to the two S16 homologs decreased gradually in the presence of dextran 20. To investigate the origin of this decrease, we studied the BODIPY quantum yield in three protein variants in the presence of a tyrosine-labeled dextran. The experiments revealed distinct tyrosine quenching behaviors of BODIPY in the three variants, suggesting a dynamic local interaction between dextran and one particular S16 variant. PMID:25028882

  4. Transcriptomic Changes in Osteoblasts Following Endothelial Cell-Cocultivation Suggest a Role of Extracellular Matrix in Cellular Interaction.

    PubMed

    Lampert, Florian M; Simunovic, Filip; Finkenzeller, Günter; Pfeifer, Dietmar; Stark, G Björn; Winninger, Oscar; Steiner, Dominik

    2016-08-01

    Vascularization is important for bone development, fracture healing and engineering of artificial bone tissue. In the context of bone tissue engineering, it was shown that coimplantation of human primary umbilical vein endothelial cells (HUVECs) and human osteoblasts (hOBs) results in the formation of functional blood vessels and enhanced bone regeneration. Implanted endothelial cells do not only contribute to blood vessel formation, but also support proliferation, cell survival and osteogenic differentiation of coimplanted hOBs. These effects are partially mediated by direct heterotypic cell contacts. In a previous report we could show that cocultivated hOBs strongly increase the expression of genes involved in extracellular matrix (ECM) formation in HUVECs, suggesting that ECM may be involved in the intercellular communication between hOBs and HUVECs. The present study aimed at investigating whether comparable changes occur in hOBs. We therefore performed a microarray analysis of hOBs cultivated in direct contact with HUVECs, revealing 1,004 differentially expressed genes. The differentially expressed genes could be assigned to the functional clusters ECM, proliferation, apoptosis and osteogenic differentiation. The microarray data could be confirmed by performing quantitative real time RT-PCR on selected genes. Furthermore, we could show that the ECM produced by HUVECs increased the expression of the osteogenic differentiation marker alkaline phosphatase (ALP) in hOBs. In summary, our data demonstrate that HUVECs provoke complex changes in gene expression patterns in cocultivated hOBs and that ECM plays and important role in this interaction. J. Cell. Biochem. 117: 1869-1879, 2016. © 2016 Wiley Periodicals, Inc. PMID:26754918

  5. Long-term dynamics emerging in floodplains and deltas from the interactions between hydrology and society in a changing climate

    NASA Astrophysics Data System (ADS)

    Di Baldassarre, Giuliano; Viglione, Alberto; Yan, Kun; Brandimarte, Luigia; Blöschl, Günter

    2014-05-01

    Economic losses and fatalities associated to flood events have increased dramatically over the past decades. This situation might worsen in the near future because of rapid urbanization of many floodplains and deltas, along with enhancement of flood water levels as a result of human interventions, climate variability or sea level rise. To explore future dynamics, we developed a novel approach, which takes into account the dynamic nature of flood risk by an explicit treatment of the interactions and feedbacks between the hydrological and social components of flood risk (i.e. probability of flooding, and potential adverse consequences). In particular, we developed a socio-hydrological model that allows considering how the frequency and magnitude of flooding shapes the evolution of societies, while, at the same time, dynamic societies shape the frequency and magnitude of flooding. We then use this model to simulate long-term dynamics of different types of societies under hydrological change, e.g. increasing flood frequency. Based on the study of long-term dynamics of different floodplains and deltas around the world (e.g. Netherlands, Bangladesh), we identify two main typologies of flood-shaped societies: i) techno-societies, which "fight floods", and typically deal with risk by building and strengthening flood protection structures, such as levees or dikes; and ii) green-societies, which "lives with floods", and mainly cope with risk via adaptation measures, such as resettling out of flood prone areas. The outcomes of this study are relevant for the management of deltas and floodplains as they allow a comparison of long-term dynamics between diverse types of societies in terms of robustness to hydrological change.

  6. Gender and age effects interact in preschoolers' help-seeking: evidence for differential responses to changes in task difficulty.

    PubMed

    Thompson, R Bruce; Cothran, Thomas; McCall, Daniel

    2012-11-01

    This study explored preschool age and gender differences in help-seeking within the theoretical framework of scaffolded problem-solving and self-regulation (Bruner, 1986; Rogoff, 1990; Vygotsky, 1978; 1986). Within-subject analyses tracked changes in help-seeking among 62 preschoolers (34 boys, 28 girls, mean age 4.22 years) solving a challenging puzzle with an adult. The goal was to document whether age and gender interact with fluctuating difficulty to affect children's spontaneous help-seeking. ANOVAs indicated that girls used more help-seeking during difficult segments of the task, despite performance equal to the boys. This pattern was strongest among older girls, who outperformed all other children and used the most help-seeking. Partial correlations, controlling for solving time, indicated that age predicted children's help-seeking during the most difficult segments of the task, but only among girls. Gender differences in social-linguistic maturation and cognitive development are discussed within the framework of Vygotskian theory and related educational practice. PMID:22217160

  7. Nitrogen Level Changes the Interactions between a Native (Scirpus triqueter) and an Exotic Species (Spartina anglica) in Coastal China

    PubMed Central

    Li, Hong-li; Lei, Guang-chun; Zhi, Ying-biao; An, Shu-qing; Huang, He-ping; Ouyang, Yan; Zhao, Lei; Deng, Zi-fa; Liu, Yu-hong

    2011-01-01

    The exotic species Spartina anglica, introduced from Europe in 1963, has been experiencing a decline in the past decade in coastal China, but the reasons for the decline are still not clear. It is hypothesized that competition with the native species Scirpus triqueter may have played an important role in the decline due to niche overlap in the field. We measured biomass, leaf number and area, asexual reproduction and relative neighborhood effect (RNE) of the two species in both monoculture and mixture under three nitrogen levels (control, low and high). S. anglica showed significantly lower biomass accumulation, leaf number and asexual reproduction in mixture than in monoculture. The inter- and intra-specific RNE of S. anglica were all positive, and the inter-specific RNE was significantly higher than the intra-specific RNE in the control. For S. triqueter, inter- and intra-specific RNE were negative at the high nitrogen level but positive in the control and at the low nitrogen level. This indicates that S. triqueter exerted an asymmetric competitive advantage over S. anglica in the control and low nitrogen conditions; however, S. anglica facilitated growth of S. triqueter in high nitrogen conditions. Nitrogen level changed the interactions between the two species because S. triqueter better tolerated low nitrogen. Since S. anglica is increasingly confined to upper, more nitrogen-limited marsh areas in coastal China, increased competition from S. triqueter may help explain its decline. PMID:21998676

  8. First-principles study of magnetic interactions in 3d transition metal-doped phase-change materials

    NASA Astrophysics Data System (ADS)

    Fukushima, Tetsuya; Katayama-Yoshida, Hiroshi; Sato, Kazunori; Fujii, Hitoshi; Rabel, Elias; Zeller, Rudolf; Dederichs, Peter; Zhang, Wei; Mazzarello, Riccardo

    2015-03-01

    We investigate the electronic structure and the magnetic properties of the prototypical phase-change material Ge2Sb2Te5 (GST) doped with V, Cr, Mn and Fe by density functional calculations. Both the supercell method and the coherent potential approximation (CPA) are employed to describe this complex substitutionally disordered system. As regards the first approach, we consider a large unit cell containing 1000 sites to model the random distribution of the cations and of the impurities in doped cubic GST. Such a large-scale electronic structure calculation is performed using the program KKRnano, where the full potential screened Korringa-Kohn-Rostoker Green's function method is optimized by a massively parallel linear scaling all electron algorithm. We find that ferromagnetic states are favorable in the cases of V and Cr doping, due to the double exchange mechanism. The ferromagnetic interaction is particularly strong in the case of Cr. As a result, high Curie temperatures close to room temperatures are obtained for large Cr concentration.

  9. Changes in albumin/platelet interaction with an artificial surface--due to a antibiotics, pyridoxal phosphate, and lymphocytes

    SciTech Connect

    Chandy, T.; Sharma, C.P.

    1988-04-01

    Protein adsorption and platelet adhesion are two important biological processes arising at the blood prosthetic interface. The effect of certain antibiotics, namely, neomycin, gentamicin, ampicillin, penicillin-G, and streptomycin to modulate the albumin polycarbonate surface interaction was investigated using /sup 125/I albumin from a protein mixture in the presence and absence of isolated calf lymphocytes. This study also demonstrated the changes in platelet-surface adhesion with these antibiotics. The effect of pyridoxal phosphate to modulate the red blood cell-mediated platelet-surface attachment was also attempted. It appears from pyridoxal phosphate studies that pyridoxal 5'-phosphate (PLP) could modify the surface-platelet attachment. It also inhibited the fibrinogen-induced platelet adhesion. It seems, the addition of antibiotics to the polymerprotein system increased the level of surface-bound albumin variably whereas lymphocytes incubated in the medium did not affect the surface-albumin concentration with time course. These antibiotics also inhibited the surface-induced platelet adhesion to variable degrees. Our earlier studies have indicated that certain antibiotics or antiplatelet drugs can inhibit the fibrinogen binding to an artificial surface. Therefore, it may be possible that the enhanced albumin-surface concentration or reduced fibrinogen-surface binding, in the presence of these antibiotics, may itself be one of the parameter for a reduced platelet-surface attachment, which may also improve the blood compatibility of the substrate. A better understanding of the mechanism of antibiotics is needed in in vivo conditions to correlate these findings.

  10. CP asymmetry in B{sup 0}{yields}K{sup -}{pi}{sup +} from supersymmetric flavor changing interactions

    SciTech Connect

    He Xiaogang; Li Chongsheng; Yang Lilin

    2005-03-01

    Recently BABAR and Belle Collaborations have measured direct CP asymmetry A{sub CP}=-0.114{+-}0.020 in B{sup 0}{yields}K{sup -}{pi}{sup +}. The experimental value is substantially different from the QCD factorization prediction. We show that supersymmetry flavor changing neutral current interaction via gluonic dipole can explain the difference. CP asymmetries in other B{yields}K{pi} decays are predicted to be sizable. Taking this asymmetry as a constraint, we find that the allowed supersymmetry parameter space is considerably reduced compared with constraint from B{yields}X{sub s}{gamma} alone. We also find the allowed time-dependent CP asymmetries S{sub f} in B{sup 0}{yields}K*{sup 0}{gamma}{yields}{pi}{sup 0}K{sub S}{gamma} and B{sup 0}{yields}{phi}K{sub S} to be large. These predictions are quite different than those predicted in the standard model and can be tested in the near future.

  11. Seasonal Changes Affect Root Prunasin Concentration in Prunus serotina and Override Species Interactions between P. serotina and Quercus petraea.

    PubMed

    Robakowski, Piotr; Bielinis, Ernest; Stachowiak, Jerzy; Mejza, Iwona; Bułaj, Bartosz

    2016-03-01

    The allocation of resources to chemical defense can decrease plant growth and photosynthesis. Prunasin is a cyanogenic glycoside known for its role in defense against herbivores and other plants. In the present study, fluctuations of prunasin concentrations in roots of Prunus serotina seedlings were hypothesized to be: (1) dependent on light, air temperature, and humidity; (2) affected by competition between Prunus serotina and Quercus petraea seedlings, with mulching with Prunus serotina leaves; (3) connected with optimal allocation of resources. For the first time, we determined prunasin concentration in roots on several occasions during the vegetative season. The results indicate that seasonal changes have more pronounced effects on prunasin concentration than light regime and interspecific competition. Prunus serotina invested more nitrogen in the synthesis of prunasin under highly restricted light conditions than in higher light environments. In full sun, prunasin in roots of Prunus serotina growing in a monoculture was correlated with growth and photosynthesis, whereas these relationships were not found when interspecific competition with mulching was a factor. The study demonstrates that prunasin concentration in Prunus serotina roots is the result of species-specific adaptation, light and temperature conditions, ontogenetic shift, and, to a lesser extent, interspecific plant-plant interactions. PMID:26961681

  12. Effect of cooperative learning strategies on student verbal interactions and achievement during conceptual change instruction in 10th grade general science

    NASA Astrophysics Data System (ADS)

    Lonning, Robert A.

    This study evaluated the effects of cooperative learning on students' verbal interaction patterns and achievement in a conceptual change instructional model in secondary science. Current conceptual change instructional models recognize the importance of student-student verbal interactions, but lack specific strategies to encourage these interactions. Cooperative learning may provide the necessary strategies. Two sections of low-ability 10th-grade students were designated the experimental and control groups. Students in both sections received identical content instruction on the particle model of matter using conceptual change teaching strategies. Students worked in teacher-assigned small groups on in-class assignments. The experimental section used cooperative learning strategies involving instruction in collaborative skills and group evaluation of assignments. The control section received no collaborative skills training and students were evaluated individually on group work. Gains on achievement were assessed using pre- and posttreatment administrations of an investigator-designed short-answer essay test. The assessment strategies used in this study represent an attempt to measure conceptual change. Achievement was related to students' ability to correctly use appropriate scientific explanations of events and phenomena and to discard use of naive conceptions. Verbal interaction patterns of students working in groups were recorded on videotape and analyzed using an investigator-designed verbal interaction scheme. The targeted verbalizations used in the interaction scheme were derived from the social learning theories of Piaget and Vygotsky. It was found that students using cooperative learning strategies showed greater achievement gains as defined above and made greater use of specific verbal patterns believed to be related to increased learning. The results of the study demonstrated that cooperative learning strategies enhance conceptual change instruction. More

  13. Global and regional effects of land-use change on climate in 21st century simulations with interactive carbon cycle

    NASA Astrophysics Data System (ADS)

    Boysen, L. R.; Brovkin, V.; Arora, V. K.; Cadule, P.; de Noblet-Ducoudré, N.; Kato, E.; Pongratz, J.; Gayler, V.

    2014-09-01

    Biogeophysical (BGP) and biogeochemical (BGC) effects of land-use and land cover change (LULCC) are separated at the global and regional scales in new interactive CO2 simulations for the 21st century. Results from four earth system models (ESMs) are analyzed for the future RCP8.5 scenario from simulations with and without land-use and land cover change (LULCC), contributing to the Land-Use and Climate, IDentification of robust impacts (LUCID) project. Over the period 2006-2100, LULCC causes the atmospheric CO2 concentration to increase by 12, 22, and 66 ppm in CanESM2, MIROC-ESM, and MPI-ESM-LR, respectively. Statistically significant changes in global near-surface temperature are found in three models with a BGC-induced global mean annual warming between 0.07 and 0.23 K. BGP-induced responses are simulated by three models in areas of intense LULCC of varying sign and magnitude (between -0.47 and 0.10 K). Modifications of the land carbon pool by LULCC are disentangled in accordance with processes that can lead to increases and decreases in this carbon pool. Global land carbon losses due to LULCC are simulated by all models: 218, 57, 35 and 34 Gt C by MPI-ESM-LR, MIROC-ESM, IPSL-CM5A-LR and CanESM2, respectively. On the contrary, the CO2-fertilization effect caused by elevated atmospheric CO2 concentrations due to LULCC leads to a land carbon gain of 39 Gt C in MPI-ESM-LR and is almost negligible in the other models. A substantial part of the spread in models' responses to LULCC is attributed to the differences in implementation of LULCC (e.g., whether pastures or crops are simulated explicitly) and the simulation of specific processes. Simple idealized experiments with clear protocols for implementing LULCC in ESMs are needed to increase the understanding of model responses and the statistical significance of results, especially when analyzing the regional-scale impacts of LULCC.

  14. Identification of Three Interactions to Determine the Conformation Change and to Maintain the Function of Kir2.1 Channel Protein

    NASA Astrophysics Data System (ADS)

    Li, Jun-Wei; Xiao, Shao-Ying; Xie, Xiao-Xiao; Yu, Hui; Zhang, Hai-Lin; Zhan, Yong; An, Hai-Long

    2015-02-01

    We find that a conserved mutation residue Glu to residue Asp (E303D), which both have the same polar and charged properties, makes Kir2.1 protein lose its function. To understand the mechanism, we identify three interactions which control the conformation change and maintain the function of the Kir2.1 protein by combining homology modeling and molecular dynamics with targeted molecular dynamics. We find that the E303D mutation weakens these interactions and results in the loss of the related function. Our data indicate that not only the amino residues but also the interactions determine the function of proteins.

  15. Changes in air quality and tropospheric composition due to depletion of stratospheric ozone and interactions with climate.

    PubMed

    Tang, X; Wilson, S R; Solomon, K R; Shao, M; Madronich, S

    2011-02-01

    Air pollution will be directly influenced by future changes in emissions of pollutants, climate, and stratospheric ozone, and will have significant consequences for human health and the environment. UV radiation is one of the controlling factors for the formation of photochemical smog, which includes tropospheric ozone (O(3)) and aerosols; it also initiates the production of hydroxyl radicals (˙OH), which control the amount of many climate- and ozone-relevant gases (e.g., methane and HCFCs) in the atmosphere. Numerical models predict that future changes in UV radiation and climate will modify the trends and geographic distribution of ˙OH, thus affecting the formation of photochemical smog in many urban and regional areas. Concentrations of ˙OH are predicted to decrease globally by an average of 20% by 2100, with local concentrations varying by as much as a factor of two above and below current values. However, significant differences between modelled and measured values in a limited number of case studies show that chemistry of hydroxyl radicals in the atmosphere is not fully understood. Photochemically produced tropospheric ozone is projected to increase. If emissions of anthropogenic air pollutants from combustion of fossil fuels, burning of biomass, and agricultural activities continue to increase, concentrations of tropospheric O(3) will tend to increase over the next 20-40 years in certain regions of low and middle latitudes because of interactions of emissions, chemical processes, and climate change. Climate-driven increases in temperature and humidity will also increase production of tropospheric O(3) in polluted regions, but reduce it in more pristine regions. Higher temperatures tend to increase emissions of nitrogen oxides (NO(x)) from some soils and release of biogenic volatile organic compounds (VOCs) from vegetation, leading to greater background concentrations of ozone in the troposphere. The net effects of future changes in UV radiation

  16. Evidence of the observed change in the atmosphere-ocean interactions over the South China Sea during summer in a regional climate model

    NASA Astrophysics Data System (ADS)

    Jang, Hye-Yeong; Yeh, Sang-Wook; Chang, Eun-Chul; Kim, Baek-Min

    2016-01-01

    The South China Sea plays a key role to change the precipitation variability in East Asia by influencing the northward moisture transport. Previous study found that there exist changes in atmosphere-ocean interactions over the South China Sea (SCS) before and after the late 1990s during boreal summer (June-July-August) in the observations. This study further supports such changes using two simulations of the atmospheric regional climate model (RCM) forced by historical sea surface temperature (SST). The control run is forced by historical SSTs, which are prescribed in the entire domain in the RCM. In addition to the control run, an additional idealized experiment is conducted, i.e., the historical SSTs are prescribed in the SCS only and the climatological SST is prescribed outside the SCS to examine the changes in the atmosphere-ocean interactions in the SCS. It is found that the simultaneous correlation coefficient between SST and precipitation changes significantly over the SCS before and after the late 1990s. This result supports the notion that there are significant changes in atmosphere-ocean interactions over the SCS before and after the late 1990, which affects the ability of the RCM to simulate precipitation variability accurately relative to observation. This result implies that the simulations of atmospheric circulation model results forced by observed SST before the late 1990 should be cautiously interpreted because the observed SST anomalies are forced by the atmosphere.

  17. Changes in physical activity levels, lesson context, and teacher interaction during physical education in culturally and linguistically diverse Australian schools

    PubMed Central

    2012-01-01

    Background Recent data show that only 15% of Australian adolescents participate in adequate amounts of physical activity (PA) and those students from Asian and Middle-Eastern backgrounds in Grades 6–12 are significantly less active than their English-speaking background peers. Schools have recently been recognised as the most widely used and cost-effective setting for promoting PA among youth and one domain within schools where PA can occur regularly for all youth, regardless of cultural background or socio-economic status, is during physical education (PE). Methods This study describes changes in physical activity (PA), lesson context and teacher interaction in physical education over the first two years in culturally and linguistically diverse secondary schools. Grade 7 PE classes in six schools were randomly observed using systematic direct observation (n = 81) and then followed up over the same period (n = 51) twelve months later. Results There was no significant decline in moderate-to-vigorous physical activity (MVPA) during PE (MD = −4.8%; p = .777), but a significant decline and medium negative effect in time spent in vigorous physical activity (VPA) (MD = −7.9%; p = .009) during PE was observed. Significant declines and large negative effects over time in percentage of PE time spent in management (MD = −8.8%; p < .001) and the number of observations where teachers promoted PA (MD = −20.7%; p < .001). Conclusions The decline of VPA and teacher promotion of PA in culturally and linguistically diverse schools is of concern. Given the declines in VPA and the increases in time spent in game play, further research is needed to ascertain whether PE instruction could be improved by focussing on skill instruction and fitness in a games-based PE instruction model. Further research for increasing teacher promotion of PA during PE is needed. PMID:22989149

  18. Changes in Intensity of Serotonin Syndrome Caused by Adverse Interaction between Monoamine Oxidase Inhibitors and Serotonin Reuptake Blockers

    PubMed Central

    Tao, Rui; Rudacille, Mary; Zhang, Gongliang; Ma, Zhiyuan

    2014-01-01

    Drug interaction between inhibitors of monoamine oxidase (MAOIs) and selective serotonin (5-hydroxytryptamine, 5-HT) reuptake (SSRIs) induces serotonin syndrome, which is usually mild but occasionally severe in intensity. However, little is known about neural mechanisms responsible for the syndrome induction and intensification. In this study, we hypothesized that the syndrome induction and intensity utilize two different but inter-related mechanisms. Serotonin syndrome is elicited by excessive 5-HT in the brain (presynaptic mechanism), whereas syndrome intensity is attributed to neural circuits involving 5-HT2A and NMDA receptors (postsynaptic mechanism). To test this hypothesis, basal 5-HT efflux and postsynaptic circuits were pharmacologically altered in rats by once daily pretreatment of the MAOI clorgyline for 3, 6, or 13 days. Syndrome intensity was estimated by measuring 5-HT efflux, neuromuscular activity, and body-core temperature in response to challenge injection of clorgyline combined with the SSRI paroxetine. Results showed that the onset of serotonin syndrome is caused by 5-HT efflux exceeding 10-fold above baseline, confirming the presynaptic hypothesis. The neuromuscular and body-core temperature abnormalities, which were otherwise mild in drug-naive rats, were significantly intensified to a severe level in rats pretreated with daily clorgyline for 3 and 6 days but not in rats pretreated for 13 days. The intensified effect was blocked by M100907 and MK-801, suggesting that variation in syndrome intensity was mediated through a 5-HT2A and NMDA receptor-engaged circuit. Therefore, we concluded that pretreatments of MAOI pharmacologically alter the activity of postsynaptic circuits, which is responsible for changes in syndrome intensity. PMID:24577320

  19. Changes in rainfall amount and frequency do not affect the outcome of the interaction between the shrub Retama sphaerocarpa and its neighbouring grasses in two semiarid communities

    PubMed Central

    Soliveres, Santiago; García-Palacios, Pablo; Maestre, Fernando T.; Escudero, Adrián; Valladares, Fernando

    2015-01-01

    We evaluated the net outcome of the interaction between the shrub Retama sphaerocarpa, our target plant, and different herbaceous neighbours in response to changes in the magnitude and frequency of rainfall events during three years. The experiment was conducted in natural and anthropogenic grasslands dominated by a perennial stress-tolerator and ruderal annual species, respectively. In spite of the neutral or positive effects of neighbours on water availability, neighbouring plants reduced the performance of Retama juveniles, suggesting competition for resources other than water. The negative effects of grasses on the photochemical efficiency of Retama juveniles decreased with higher water availabilities or heavier irrigation pulses, depending on the grassland studied; however, these effects did not extent to the survival and growth of Retama juveniles. Our findings show the prevalence of competitive interactions among the studied plants, regardless of the water availability and its temporal pattern. These results suggest that positive interactions may not prevail under harsher conditions when shade-intolerant species are involved. This study could be used to further refine our predictions of how plant-plant interactions will respond to changes in rainfall, either natural or increased by the ongoing climatic change, in ecosystems where grass-shrubs interactions are prevalent. PMID:25914429

  20. Predicting Day-to-Day Changes in Students' School-Related Affect from Daily Academic Experiences and Social Interactions

    ERIC Educational Resources Information Center

    Altermatt, Ellen Rydell

    2015-01-01

    This study examined the role that everyday academic successes and failures--and the interactions with family members and peers that follow these events--play in predicting day-to-day changes in children's emotional responses to school. Middle school students (N = 101; mean age = 11.62 years) completed daily assessments of their academic…

  1. Developing a model for effects of climate change on human health and health-environment interactions: Heat stress in Austin, Texas

    EPA Science Inventory

    Background/Question/Methods In December, 2010, a consortium of EPA, Centers for Disease Control, and state and local health officials convened in Austin, Texas for a “participatory modeling workshop” on climate change effects on human health and health-environment interactions. ...

  2. Focus Groups as Sites of Influential Interaction: Building Communicative Self-Efficacy and Effecting Attitudinal Change in Discussing Controversial Topics

    ERIC Educational Resources Information Center

    Zorn, Theodore E.; Roper, Juliet; Broadfoot, Kirsten; Weaver, C. Kay

    2006-01-01

    Although most focus group theorists consider interaction to be a defining feature of focus groups, the influence that occurs through this interaction has been under-theorized. We argue that two important forms of influence may occur: influence on people's beliefs about the substantive issues under discussion and influence on self-efficacy beliefs.…

  3. The Influence of Attachment Pattern on Developmental Changes in Peer Interaction from the Toddler to the Preschool Period.

    ERIC Educational Resources Information Center

    Jacobson, Joseph L.; Wille, Diane E.

    1986-01-01

    Investigates the influence of infant-mother attachment patterns on the development of peer interaction between the toddler and preschool periods. Notes that, in an initial encounter with an unfamiliar peer, attachment patterns appear to be related more to the child's attractiveness as an interactive partner than to the child's own active interest…

  4. Techniques for integrating the animations, multimedia, and interactive features of NASA’s climate change website, Climate Change: NASA’s Eyes on the Earth, into the classroom to advance climate literacy and encourage interest in STEM disciplines

    NASA Astrophysics Data System (ADS)

    Tenenbaum, L. F.; Jackson, R.; Greene, M.

    2009-12-01

    I developed a variety of educational content for the "Climate Change: NASA’s Eyes on the Earth" website, notably an interactive feature for the "Key Indicators: Ice Mass Loss" link that includes photo pair images of glaciers around the world, changes in Arctic sea ice extent videos, Greenland glacial calving time lapse videos, and Antarctic ice shelf break up animations, plus news pieces and a Sea Level Quiz. I integrated these resources and other recent NASA and JPL climate and oceanography data and information into climate change components of Oceanography Lab exercises, Oceanography lectures and Introduction to Environmental Technology courses. I observed that using these Internet interactive features in the classroom greatly improved student participation, topic comprehension, scientific curiosity and interest in Earth and climate science across diverse student populations. Arctic Sea Ice Extent Summer 2007 Credit: NASA

  5. Interaction between Cities and Climate Change: Modelling Urban Morphology and Local Urban Planning Scenarios from Open Datasets across European Cities

    NASA Astrophysics Data System (ADS)

    Thomas, Bart; Stevens, Catherine; Grommen, Mart

    2015-04-01

    Cities are characterised by a large spatiotemporal diversity of local climates induced by a superposition of various factors and processes interacting at global and regional scales but also at the micro level such as the urban heat island effect. As urban areas are known as 'hot spots' prone to climate and its variability over time leading to changes in the severity and occurrence of extreme events such as heat waves, it is of crucial importance to capture the spatial heterogeneity resulting from variations in land use land cover (LULC) and urban morphology in an effective way to drive local urban climate simulations. The first part of the study conducted in the framework of the NACLIM FP7 project funded by the European Commission focusses on the extraction of land surface parameters linked to urban morphology characteristics from detailed 3D city models and their relationship with openly accessible European datasets such as the degree of soil sealing and disaggregated population densities from the European Environment Agency (EEA) and the Joint Research Centre (JRC). While it has been demonstrated that good correlations can be found between those datasets and the planar and frontal area indices, the present work has expanded the research to other urban morphology parameters including the average and variation of the building height and the sky view factor. Correlations up to 80% have been achieved depending on the considered parameter and the specific urban area including the cities of Antwerp (Belgium), Berlin (Germany) and Almada (Portugal) represented by different climate and urban characteristics. Moreover, the transferability of the established relations has been investigated across the various cities. Secondly, a flexible and scalable approach as a function of the required the level of detail has been elaborated to update the various morphology parameters in case of integration with urban planning data to analyse the local impact of future land use scenarios

  6. Plant Interactions with Changes in Coverage of Biological Soil Crusts and Water Regime in Mu Us Sandland, China

    PubMed Central

    Gao, Shuqin; Pan, Xu; Cui, Qingguo; Hu, Yukun; Ye, Xuehua; Dong, Ming

    2014-01-01

    Plant interactions greatly affect plant community structure. Dryland ecosystems are characterized by low amounts of unpredictable precipitation as well as by often having biological soil crusts (BSCs) on the soil surface. In dryland plant communities, plants interact mostly as they compete for water resources, and the direction and intensity of plant interaction varies as a function of the temporal fluctuation in water availability. Since BSCs influence water redistribution to some extent, a greenhouse experiment was conducted to test the hypothesis that the intensity and direction of plant interactions in a dryland plant community can be modified by BSCs. In the experiment, 14 combinations of four plant species (Artemisia ordosica, Artemisia sphaerocephala, Chloris virgata and Setaria viridis) were subjected to three levels of coverage of BSCs and three levels of water supply. The results show that: 1) BSCs affected plant interaction intensity for the four plant species: a 100% coverage of BSCs significantly reduced the intensity of competition between neighboring plants, while it was highest with a 50% coverage of BSCs in combination with the target species of A. sphaerocephala and C. virgata; 2) effects of the coverage of BSCs on plant interactions were modified by water regime when the target species were C. virgata and S. viridis; 3) plant interactions were species-specific. In conclusion, the percent coverage of BSCs affected plant interactions, and the effects were species-specific and could be modified by water regimes. Further studies should focus on effects of the coverage of BSCs on plant-soil hydrological processes. PMID:24498173

  7. The contributions of soil-moisture interactions to climate change in the tropics in CMIP5 projections from the GLACE-CMIP5 experiment

    NASA Astrophysics Data System (ADS)

    May, Wilhelm; Rummukainen, Markku; Meier, Arndt

    2015-04-01

    The contributions of the projected changes in soil moisture to the overall climate change in the tropics at the end of the 21st century are quantified using the simulations from the GLACE-CMIP5 experiment. This is done by directly comparing the overall projected future changes in climate, which are partly related to changes in soil moisture, to the changes in climate that are not affected by any changes in soil moisture. As the five different climate models contributing to the experiment, i.e., CESM, EC-EARTH, GDFL, IPSL and MPI-ESM show quite different geographical distributions of the future changes in soil moisture in the tropics as well as different magnitudes, we do not consider ensemble mean values based on the corresponding simulations with these models but rather analyse the simulations from the different models separately. This allows for quantifying the contributions of the projected changes in soil moisture to climate change in the tropics for each climate model despite the different characteristics of the soil moisture changes themselves. We focus on two aspects of the interactions of the soil moisture with climate, i.e., the soil moisture-temperature coupling and the soil moisture-precipitation coupling/feedback. The simulations show marked future changes in soil moisture content in the tropics, with a general tendency of increases in the central parts of the tropics and decreases in the subtropics. These changes are associated with corresponding changes in precipitation, with an overall tendency of a 5change in soil moisture in response to a precipitation change of 1 mm/d. The changes in soil moisture content are found to give major contributions to the overall climate change in the tropics. This is particularly the case for the latent and sensible heat fluxes as well as near-surface temperature, where more than 80moisture changes. For precipitation, on the other hand, 30-40overall future changes are induced by the changes in soil moisture. The

  8. An intravital microscopy study of radiation-induced changes in permeability and leukocyte-endothelial cell interactions in the microvessels of the rat pia mater and cremaster muscle.

    PubMed

    Gaber, M Waleed; Yuan, Hong; Killmar, John T; Naimark, Michael D; Kiani, Mohammad F; Merchant, Thomas E

    2004-04-01

    Using intravital microscopy and a closed window method, we measured irradiation-induced changes in the vascular permeability and cell interactions in microcirculation networks of the rat pia mater; the same effects were monitored in the cremaster muscle as a control. The closed cranial window has many advantages, including long-term direct visualization of microcirculation. The method allows for repeated testing of the same vessel or network, thereby reducing variability. The method also allows for measurement of permeability changes and the accompanying leukocyte-endothelial cell interactions in the same network or vessel, which permits correlative studies of these phenomena. However, this method is not without challenges. The optical conditions are difficult, because the brain is three-dimensional and its parenchyma is more complex than the thinner, flatter peripheral tissues. To overcome this limitation, we performed a dynamic background subtraction. The background is dynamically related to vessel intensity, and changes in intensity were determined by eliminating the effects of neighboring and underlying vessels. We applied this method to studying the effects of ionizing radiation on the blood-brain barrier (BBB) permeability and cell interactions and the modulation of these effects by anti-ICAM-1 antibodies. Our results demonstrate that this method is sensitive to changes in these properties of the BBB. PMID:15063835

  9. DNA Methylation Variants at HIF3A Locus, B-Vitamin Intake, and Long-term Weight Change: Gene-Diet Interactions in Two U.S. Cohorts.

    PubMed

    Huang, Tao; Zheng, Yan; Qi, Qibin; Xu, Min; Ley, Sylvia H; Li, Yanping; Kang, Jae H; Wiggs, Janey; Pasquale, Louis R; Chan, Andrew T; Rimm, Eric B; Hunter, David J; Manson, JoAnn E; Willett, Walter C; Hu, Frank B; Qi, Lu

    2015-09-01

    The first epigenome-wide association study of BMI identified DNA methylation at an HIF3A locus associated with BMI. We tested the hypothesis that DNA methylation variants are associated with BMI according to intake of B vitamins. In two large cohorts, we found significant interactions between the DNA methylation-associated HIF3A single nucleotide polymorphism (SNP) rs3826795 and intake of B vitamins on 10-year changes in BMI. The association between rs3826795 and BMI changes consistently increased across the tertiles of total vitamin B2 and B12 intake (all P for interaction <0.01). The differences in the BMI changes per increment of minor allele were -0.10 (SE 0.06), -0.01 (SE 0.06), and 0.12 (SE 0.07) within subgroups defined by increasing tertiles of total vitamin B2 intake and -0.10 (SE 0.06), -0.01 (SE 0.06), and 0.10 (SE 0.07) within subgroups defined by increasing tertiles of total vitamin B12 intake. In two independent cohorts, a DNA methylation variant in HIF3A was associated with BMI changes through interactions with total or supplemental vitamin B2, vitamin B12, and folate. These findings suggest a potential causal relation between DNA methylation and adiposity. PMID:26001398

  10. Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae Pv. phaseolicola.

    PubMed

    O'Leary, Brendan M; Neale, Helen C; Geilfus, Christoph-Martin; Jackson, Robert W; Arnold, Dawn L; Preston, Gail M

    2016-10-01

    The apoplast is the arena in which endophytic pathogens such as Pseudomonas syringae grow and interact with plant cells. Using metabolomic and ion analysis techniques, this study shows how the composition of Phaseolus vulgaris leaf apoplastic fluid changes during the first six hours of compatible and incompatible interactions with two strains of P. syringae pv. phaseolicola (Pph) that differ in the presence of the genomic island PPHGI-1. Leaf inoculation with the avirulent island-carrying strain Pph 1302A elicited effector-triggered immunity (ETI) and resulted in specific changes in apoplast composition, including increases in conductivity, pH, citrate, γ-aminobutyrate (GABA) and K(+) , that are linked to the onset of plant defence responses. Other apoplastic changes, including increases in Ca(2+) , Fe(2/3+) Mg(2+) , sucrose, β-cyanoalanine and several amino acids, occurred to a relatively similar extent in interactions with both Pph 1302A and the virulent, island-less strain Pph RJ3. Metabolic footprinting experiments established that Pph preferentially metabolizes malate, glucose and glutamate, but excludes certain other abundant apoplastic metabolites, including citrate and GABA, until preferred metabolites are depleted. These results demonstrate that Pph is well-adapted to the leaf apoplast metabolic environment and that loss of PPHGI-1 enables Pph to avoid changes in apoplast composition linked to plant defences. PMID:27239727

  11. Analytical applications of partitioning in aqueous two-phase systems: Exploring protein structural changes and protein-partner interactions in vitro and in vivo by solvent interaction analysis method.

    PubMed

    Zaslavsky, Boris Y; Uversky, Vladimir N; Chait, Arnon

    2016-05-01

    This review covers the fundamentals of protein partitioning in aqueous two-phase systems (ATPS). Included is a review of advancements in the analytical application of solute partitioning in ATPS over the last two decades, with multiple examples of experimental data providing evidence that phase-forming polymers do not interact with solutes partitioned in ATPS. The partitioning of solutes is governed by the differences in solute interactions with aqueous media in the two phases. Solvent properties of the aqueous media in these two phases may be characterized and manipulated. The solvent interaction analysis (SIA) method, based on the solute partitioning in ATPS, may be used for characterization and analysis of individual proteins and their interactions with different partners. The current state of clinical proteomics regarding the discovery and monitoring of new protein biomarkers is discussed, and it is argued that the protein expression level in a biological fluid may be not the optimal focus of clinical proteomic research. Multiple examples of application of the SIA method for discovery of changes in protein structure and protein-partner interactions in biological fluids are described. The SIA method reveals new opportunities for discovery and monitoring structure-based protein biomarkers. PMID:26923390

  12. Development of Motivate4Change Using the Intervention Mapping Protocol: An Interactive Technology Physical Activity and Medication Adherence Promotion Program for Hospitalized Heart Failure Patients

    PubMed Central

    te Velde, Saskia J; Stut, Wim; Brug, Johannes

    2015-01-01

    Background It is important that heart failure (HF) patients adhere to their medication regimen and engage in physical activity. Evidence shows that adherence to these HF self-management behaviors can be improved with appropriate interventions. Objective To further promote medication adherence and physical activity among HF patients, we developed an intervention for hospitalized HF patients. Methods The intervention mapping protocol was applied in the development of the intervention. This entailed performing a needs assessment, defining change objectives, selecting determinants and strategies, and developing the materials. Results The resulting intervention, Motivate4Change, makes use of interactive technology and provides HF patients with personalized feedback and advice. Specific change objectives were defined. The relevant behavioral determinants for the physical activity program were practical knowledge on physical activity performance and self-efficacy for, and perceived benefits of, physical activity. For medication-taking, the selected determinants were practical knowledge on medication-taking, perceived barriers to medication-taking, beliefs about the necessity and harm regarding the medication prescribed, and beliefs about overprescribing and harm of medication in general. The change objectives and behavior change determinants were translated in feedback and advice strategies in an interactive technology program that included tailored feedback and advice, and role models in videos in which the behaviors and overcoming barriers were demonstrated. Relevant stakeholders were involved in the interventions development process. The intervention was pretested among HF patients and adjustments were made accordingly. Conclusions The interactive technology physical activity and medication adherence promotion program for hospitalized HF patients was systematically developed using the intervention mapping protocol and was based on the available theory and evidence

  13. Utilizing the trophic interactions of nematodes as indicators of changes in soil biota associated with loss of Bouteloua eriopoda grasslands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A theoretical framework of desertification has been developed within the Jornada Basin LTER that involves the rate of change and magnitude of wind and water erosion affected by spatial variation in the distribution of gap size changes from high connectivity of vegetated patches in grasslands to low ...

  14. Modelling the influence of land-use changes on biophysical and biochemical interactions at regional and global scales.

    PubMed

    Devaraju, N; Bala, G; Nemani, R

    2015-09-01

    Land-use changes since the start of the industrial era account for nearly one-third of the cumulative anthropogenic CO2 emissions. In addition to the greenhouse effect of CO2 emissions, changes in land use also affect climate via changes in surface physical properties such as albedo, evapotranspiration and roughness length. Recent modelling studies suggest that these biophysical components may be comparable with biochemical effects. In regard to climate change, the effects of these two distinct processes may counterbalance one another both regionally and, possibly, globally. In this article, through hypothetical large-scale deforestation simulations using a global climate model, we contrast the implications of afforestation on ameliorating or enhancing anthropogenic contributions from previously converted (agricultural) land surfaces. Based on our review of past studies on this subject, we conclude that the sum of both biophysical and biochemical effects should be assessed when large-scale afforestation is used for countering global warming, and the net effect on global mean temperature change depends on the location of deforestation/afforestation. Further, although biochemical effects trigger global climate change, biophysical effects often cause strong local and regional climate change. The implication of the biophysical effects for adaptation and mitigation of climate change in agriculture and agroforestry sectors is discussed. PMID:25410808

  15. Technology-Rich Learning Environments in Elementary and Secondary Schools: An Interactive Study of Physical Settings and Educational Change.

    ERIC Educational Resources Information Center

    Stuebing, Susan; And Others

    This paper reviews an ongoing study on the physical settings of education with technology at the elementary and high school levels. The study, which is multi-disciplinary in nature, is based in sites in the process of change in teaching strategies, using learning technology as a catalyst for this change to take place. The focus of the study is on…

  16. Spectroscopic investigation on the interaction of hyperbranched poly (amine) ester with model plasma protein: Effect on the structural and conformational changes

    NASA Astrophysics Data System (ADS)

    Xiao, Fengjuan; Gu, Muqing; Liang, Ye; Li, Lanlan; Luo, Yunjun

    2014-01-01

    Mechanism of interaction between hyperbranched poly (amine) ester (HPAE) and bovine serum albumin (BSA) was investigated using fluorescence, synchronous fluorescence, three-dimensional fluorescence spectra, UV-Vis spectrometry and circular dichroism (CD). The structural and conformational changes of BSA induced by HPAE were also revealed in this study. Stern-Volmer analysis of fluorescence quenching showed that BSA fluorescence was statically quenched by HPAE, which implied that ground state complex formed between BSA and HPAE. Vander Waals force and hydrogen bond played major roles in the interaction of HPAE with BSA. The distance, r between the donor (BSA) and acceptor (HPAE) was calculated based on the Forster's theory of non-radiation energy transfer and was found to be 3.24 nm. Synchronous and three-dimensional fluorescence studies showed that the interaction of BSA with HPAE induced conformational changes in BSA. The secondary structural analysis by CD spectra suggested that HPAE binding induced BSA to form a more compact conformation with about 6.9% transformation of α-helix to β-sheet. Molecular model of the interaction of HPAE with BSA was also presented according to the results of this study.

  17. Species interactions and response time to climate change: ice-cover and terrestrial run-off shaping Arctic char and brown trout competitive asymmetries

    NASA Astrophysics Data System (ADS)

    Finstad, A. G.; Palm Helland, I.; Jonsson, B.; Forseth, T.; Foldvik, A.; Hessen, D. O.; Hendrichsen, D. K.; Berg, O. K.; Ulvan, E.; Ugedal, O.

    2011-12-01

    There has been a growing recognition that single species responses to climate change often mainly are driven by interaction with other organisms and single species studies therefore not are sufficient to recognize and project ecological climate change impacts. Here, we study how performance, relative abundance and the distribution of two common Arctic and sub-Arctic freshwater fishes (brown trout and Arctic char) are driven by competitive interactions. The interactions are modified both by direct climatic effects on temperature and ice-cover, and indirectly through climate forcing of terrestrial vegetation pattern and associated carbon and nutrient run-off. We first use laboratory studies to show that Arctic char, which is the world's most northernmost distributed freshwater fish, outperform trout under low light levels and also have comparable higher growth efficiency. Corresponding to this, a combination of time series and time-for-space analyses show that ice-cover duration and carbon and nutrient load mediated by catchment vegetation properties strongly affected the outcome of the competition and likely drive the species distribution pattern through competitive exclusion. In brief, while shorter ice-cover period and decreased carbon load favored brown trout, increased ice-cover period and increased carbon load favored Arctic char. Length of ice-covered period and export of allochthonous material from catchments are major, but contrasting, climatic drivers of competitive interaction between these two freshwater lake top-predators. While projected climate change lead to decreased ice-cover, corresponding increase in forest and shrub cover amplify carbon and nutrient run-off. Although a likely outcome of future Arctic and sub-arctic climate scenarios are retractions of the Arctic char distribution area caused by competitive exclusion, the main drivers will act on different time scales. While ice-cover will change instantaneously with increasing temperature

  18. Dynamic changes in protein interaction between AKAP95 and Cx43 during cell cycle progression of A549 cells

    PubMed Central

    Chen, Xiaoxuan; Kong, Xiangyu; Zhuang, Wenxin; Teng, Bogang; Yu, Xiuyi; Hua, Suhang; Wang, Su; Liang, Fengchao; Ma, Dan; Zhang, Suhui; Zou, Xuan; Dai, Yue; Yang, Wei; Zhang, Yongxing

    2016-01-01

    Here we show that A-kinase anchoring protein 95 (AKAP95) and connexin 43 (Cx43) dynamically interact during cell cycle progression of lung cancer A549 cells. Interaction between AKAP95 and Cx43 at different cell cycle phases was examined by tandem mass spectrometry(MS/MS), confocal immunofluorescence microscopy, Western blot, and co-immunoprecipitation(Co-IP). Over the course of a complete cell cycle, interaction between AKAP95 and Cx43 occurred in two stages: binding stage from late G1 to metaphase, and separating stage from anaphase to late G1. The binding stage was further subdivided into complex binding to DNA in interphase and complex separating from DNA in metaphase. In late G1, Cx43 translocated to the nucleus via AKAP95; in anaphase, Cx43 separated from AKAP95 and aggregated between two daughter nuclei. In telophase, Cx43 aggregated at the membrane of the cleavage furrow. After mitosis, Cx43 was absent from the furrow membrane and was located in the cytoplasm. Binding between AKAP95 and Cx43 was reduced by N-(2-[P-Bromocinnamylamino]-ethyl)-5-isoquinolinesulfonmide (H89) treatment and enhanced by Forskolin. dynamic interaction between AKAP95 and Cx43 varies with cell cycle progression to regulate multiple biological processes. PMID:26880274

  19. Biochemical enhancement of transdermal delivery with magainin peptide: modification of electrostatic interactions by changing pH.

    PubMed

    Kim, Yeu-Chun; Late, Sameer; Banga, Ajay K; Ludovice, Peter J; Prausnitz, Mark R

    2008-10-01

    Magainin is a naturally occurring, pore-forming peptide that has recently been shown to increase skin permeability. This study tested the hypothesis that electrostatic forces between magainin peptides and drugs mediate drug transport across the skin. Electrostatic interaction between positively charged magainin and a negatively charged model drug, fluorescein, was attractive at pH 7.4 and resulted in a 35-fold increase in delivery across human epidermis in vitro when formulated with 2% N-lauroylsarcosine in 50% ethanol. Increasing to pH 10 or 11 largely neutralized magainin's charge, which eliminated enhancement due to magainin. Shielding electrostatic interactions with 1-2M NaCl solution similarly eliminated enhancement. Showing the opposite dependence on pH, electrostatic interaction between magainin and a positively charged anti-nausea drug, granisetron, was largely neutralized at pH 10 and resulted in a 92-fold increase in transdermal delivery. Decreasing to pH 5 increased magainin's positive charge, which repelled granisetron and progressively decreased transdermal flux. Circular dichroism analysis, multi-photon microscopy, and FTIR spectroscopy showed no significant pH effect on magainin secondary structure, magainin deposition in stratum corneum, or stratum corneum lipid order, respectively. We conclude that magainin increases transdermal delivery by a mechanism involving electrostatic interaction between magainin peptides and drugs. PMID:18601987

  20. How Rock Music Videos Can Change What Is Seen when Boy Meets Girl: Priming Stereotypic Appraisal of Social Interactions.

    ERIC Educational Resources Information Center

    Hansen, Christine H.; Hansen, Ranald D.

    1988-01-01

    Studies the capacity of sex role stereotyped portrayals of men and women found in popular rock music videos to alter viewers' impressions of a man and a woman who subsequently were seen interacting. Concludes that the videos perpetuate traditional sex role stereotypes. (FMW)

  1. Investigating the Impact of Interactive Applets on Students' Understanding of Parameter Changes to Parent Functions: An Explanatory Mixed Methods Study

    ERIC Educational Resources Information Center

    McClaran, Robin Rudd

    2013-01-01

    The technology principle in the "Principles and Standards for School Mathematics" (NCTM, 2000) states that technology plays an important role in how teachers teach mathematics and in how students learn mathematics. The purpose of this sequential explanatory mixed methods study was to examine the impact of interactive applets on students'…

  2. Changes in Images of Adolescents on Television: Sibling Interaction on Family Sitcoms in the 50's and the 80's.

    ERIC Educational Resources Information Center

    Larson, Mary Strom

    A study examined the interactions of siblings in television families in three popular sitcoms of the 1950s--"Father Knows Best,""Leave it To Beaver," and "Ozzie and Harriet." Nine episodes of each sitcom were videotaped, and the behaviors were coded using a system developed to code sibling behavior in 1980s sitcoms. Comparison of sibling behavior…

  3. Elementary School Teachers as "Targets and Agents of Change": Teachers' Learning in Interaction with Reform Science Curriculum

    ERIC Educational Resources Information Center

    Metz, Kathleen E.

    2009-01-01

    This article examines teachers' perspectives on the challenges of using a science reform curriculum, as well as their learning in interaction with the curriculum and parallel professional development program. As case studies, I selected 4 veteran teachers of 2nd or 3rd grade, with varying science backgrounds (including 2 with essentially none).…

  4. Intensive Interaction as a Novel Approach in Social Care: Care Staff's Views on the Practice Change Process

    ERIC Educational Resources Information Center

    Firth, Graham; Elford, Helen; Leeming, Catherine; Crabbe, Marion

    2008-01-01

    Background: Intensive Interaction is an approach to developing the pre-verbal communication and sociability of people with severe or profound and multiple learning disabilities and autism. Previous research has indicated many potential benefits; however, the approach is not consistently used in social care. Aim: To report on the significant and…

  5. The Changing Role Behaviors of Educational Administrators During Role Simulation Training: Perceptions of Verbal and Non-Verbal Interaction.

    ERIC Educational Resources Information Center

    Frank, Frederick P.

    Included in a current genre of studies on dyadic interaction (i.e., communication involving only two people), the study reported herein focuses on dyadic verbal, nonverbal, and proxemic behaviors and their meanings. The study is inductive in nature and is, by intent, descriptive and analytic rather than predictive. The subjects for the study were…

  6. Parenting and the Family Check-Up: Changes in Observed Parent-Child Interaction Following Early Childhood Intervention

    PubMed Central

    Sitnick, Stephanie L.; Shaw, Daniel S.; Gill, Anne; Dishion, Thomas; Winter, Charlotte; Waller, Rebecca; Gardner, Frances; Wilson, Melvin

    2016-01-01

    Coercion theory posits a cyclical relationship between harsh and coercive parent–child interactions and problem behavior beginning in early childhood. As coercive interactions have been theorized and found to facilitate the development and growth of early conduct problems, early interventions often target parenting to prevent or reduce early disruptive problem behavior. This study utilizes direct observations of parent–child interactions from the Early Steps Multisite study (N = 731; 369 boys) to examine the effect of the Family Check-Up, a family-centered intervention program, on measures of parent–child positive engagement and coercion from age 2 through 5, as well as on childhood problem behavior at age 5. Results indicate that high levels of parent–child positive engagement were associated with less parent–child coercion the following year, but dyadic coercion was unrelated to future levels of positive engagement. In addition, families assigned to the Family Check-Up showed increased levels of positive engagement at ages 3 and 5, and the association between positive engagement at age 3 and child problem behavior at age 5 was mediated by reductions in parent–child coercion at age 4. These findings provide longitudinal confirmation that increasing positive engagement in parent–child interaction can reduce the likelihood of coercive family dynamics in early childhood and growth in problem behavior. PMID:25133754

  7. Changes in air quality and tropospheric composition due to depletion of stratospheric ozone and interactions with changing climate: implications for human and environmental health.

    PubMed

    Madronich, S; Shao, M; Wilson, S R; Solomon, K R; Longstreth, J D; Tang, X Y

    2015-01-01

    UV radiation is an essential driver for the formation of photochemical smog, which includes ground-level ozone and particulate matter (PM). Recent analyses support earlier work showing that poor outdoor air quality is a major environmental hazard as well as quantifying health effects on regional and global scales more accurately. Greater exposure to these pollutants has been linked to increased risks of cardiovascular and respiratory diseases in humans and is associated globally with several million premature deaths per year. Ozone also has adverse effects on yields of crops, leading to loss of billions of US dollars each year. These detrimental effects also may alter biological diversity and affect the function of natural ecosystems. Future air quality will depend mostly on changes in emission of pollutants and their precursors, but changes in UV radiation and climate will contribute as well. Significant reductions in emissions, mainly from the energy and transportation sectors, have already led to improved air quality in many locations. Air quality will continue to improve in those cities/states that can afford controls, and worsen where the regulatory infrastructure is not available. Future changes in UV radiation and climate will alter the rates of formation of ground-level ozone and photochemically-generated particulate matter and must be considered in predictions of air quality. The decrease in UV radiation associated with recovery of stratospheric ozone will, according to recent global atmospheric model simulations, lead to increases in ground-level ozone at most locations. If correct, this will add significantly to future ground-level ozone trends. However, the spatial resolution of these global models is insufficient to inform policy at this time, especially for urban areas. UV radiation affects the atmospheric concentration of hydroxyl radicals, ˙OH, which are responsible for the self-cleaning of the atmosphere. Recent measurements confirm that, on a

  8. The interaction of human serum albumin with selected lanthanide and actinide ions: Binding affinities, protein unfolding and conformational changes.

    PubMed

    Ali, Manjoor; Kumar, Amit; Kumar, Mukesh; Pandey, Badri N

    2016-04-01

    Human serum albumin (HSA), the most abundant soluble protein in blood plays critical roles in transportation of biomolecules and maintenance of osmotic pressure. In view of increasing applications of lanthanides- and actinides-based materials in nuclear energy, space, industries and medical applications, the risk of exposure with these metal ions is a growing concern for human health. In present study, binding interaction of actinides/lanthanides [thorium: Th(IV), uranium: U(VI), lanthanum: La(III), cerium: Ce(III) and (IV)] with HSA and its structural consequences have been investigated. Ultraviolet-visible, Fourier transform-infrared, Raman, Fluorescence and Circular dichroism spectroscopic techniques were applied to study the site of metal ions interaction, binding affinity determination and the effect of metal ions on protein unfolding and HSA conformation. Results showed that these metal ions interacted with carbonyl (CO..:)/amide(N..-H) groups and induced exposure of aromatic residues of HSA. The fluorescence analysis indicated that the actinide binding altered the microenvironment around Trp214 in the subdomain IIA. Binding affinity of U(VI) to HSA was slightly higher than that of Th(IV). Actinides and Ce(IV) altered the secondary conformation of HSA with a significant decrease of α-helix and an increase of β-sheet, turn and random coil structures, indicating a partial unfolding of HSA. A correlation was observed between metal ion's ability to alter HSA conformation and protein unfolding. Both cationic effects and coordination ability of metal ions seemed to determine the consequences of their interaction with HSA. Present study improves our understanding about the protein interaction of these heavy ions and their impact on its secondary structure. In addition, binding characteristics may have important implications for the development of rational antidote for the medical management of health effects of actinides and lanthanides. PMID:26821345

  9. Understanding interaction effects of climate change and fire management on bird distributions through combined process and habitat models

    USGS Publications Warehouse

    White, Joseph D.; Gutzwiller, Kevin J.; Barrow, Wylie C.; Johnson-Randall, Lori; Zygo, Lisa; Swint, Pamela

    2011-01-01

    Avian conservation efforts must account for changes in vegetation composition and structure associated with climate change. We modeled vegetation change and the probability of occurrence of birds to project changes in winter bird distributions associated with climate change and fire management in the northern Chihuahuan Desert (southwestern U.S.A.). We simulated vegetation change in a process-based model (Landscape and Fire Simulator) in which anticipated climate change was associated with doubling of current atmospheric carbon dioxide over the next 50 years. We estimated the relative probability of bird occurrence on the basis of statistical models derived from field observations of birds and data on vegetation type, topography, and roads. We selected 3 focal species, Scaled Quail (Callipepla squamata), Loggerhead Shrike (Lanius ludovicianus), and Rock Wren (Salpinctes obsoletus), that had a range of probabilities of occurrence for our study area. Our simulations projected increases in relative probability of bird occurrence in shrubland and decreases in grassland and Yucca spp. and ocotillo (Fouquieria splendens) vegetation. Generally, the relative probability of occurrence of all 3 species was highest in shrubland because leaf-area index values were lower in shrubland. This high probability of occurrence likely is related to the species' use of open vegetation for foraging. Fire suppression had little effect on projected vegetation composition because as climate changed there was less fuel and burned area. Our results show that if future water limits on plant type are considered, models that incorporate spatial data may suggest how and where different species of birds may respond to vegetation changes.

  10. Interactive effects of water diversion and climate change for juvenile chinook salmon in the lemhi river basin (USA.).

    PubMed

    Walters, Annika W; Bartz, Krista K; McClure, Michelle M

    2013-12-01

    The combined effects of water diversion and climate change are a major conservation challenge for freshwater ecosystems. In the Lemhi Basin, Idaho (U.S.A.), water diversion causes changes in streamflow, and climate change will further affect streamflow and temperature. Shifts in streamflow and temperature regimes can affect juvenile salmon growth, movement, and survival. We examined the potential effects of water diversion and climate change on juvenile Chinook salmon (Oncorhynchus tshawytscha), a species listed as threatened under the U.S. Endangered Species Act (ESA). To examine the effects for juvenile survival, we created a model relating 19 years of juvenile survival data to streamflow and temperature and found spring streamflow and summer temperature were good predictors of juvenile survival. We used these models to project juvenile survival for 15 diversion and climate-change scenarios. Projected survival was 42-58% lower when streamflows were diverted than when streamflows were undiverted. For diverted streamflows, 2040 climate-change scenarios (ECHO-G and CGCM3.1 T47) resulted in an additional 11-39% decrease in survival. We also created models relating habitat carrying capacity to streamflow and made projections for diversion and climate-change scenarios. Habitat carrying capacity estimated for diverted streamflows was 17-58% lower than for undiverted streamflows. Climate-change scenarios resulted in additional decreases in carrying capacity for the dry (ECHO-G) climate model. Our results indicate climate change will likely pose an additional stressor that should be considered when evaluating the effects of anthropogenic actions on salmon population status. Thus, this type of analysis will be especially important for evaluating effects of specific actions on a particular species. Efectos Interactivos de la Desviación del Agua y el Cambio Climático en Individuos Juveniles de Salmón Chinook en la Cuenca del Río Lemhi (E.U.A.). PMID:24299084

  11. Understanding interaction effects of climate change and fire management on bird distributions through combined process and habitat models

    USGS Publications Warehouse

    White, Joseph D.; Gutzwiller, Kevin J.; Barrow, Wylie C.; Johnson-Randall, Lori; Zygo, Lisa; Swint, Pamela

    2011-01-01

    Avian conservation efforts must account for changes in vegetation composition and structure associated with climate change. We modeled vegetation change and the probability of occurrence of birds to project changes in winter bird distributions associated with climate change and fire management in the northern Chihuahuan Desert (southwestern U.S.A.). We simulated vegetation change in a process-based model (Landscape and Fire Simulator) in which anticipated climate change was associated with doubling of current atmospheric carbon dioxide over the next 50 years. We estimated the relative probability of bird occurrence on the basis of statistical models derived from field observations of birds and data on vegetation type, topography, and roads. We selected 3 focal species, Scaled Quail (Callipepla squamata), Loggerhead Shrike (Lanius ludovicianus), and Rock Wren (Salpinctes obsoletus), that had a range of probabilities of occurrence for our study area. Our simulations projected increases in relative probability of bird occurrence in shrubland and decreases in grassland and Yucca spp. and ocotillo (Fouquieria splendens) vegetation. Generally, the relative probability of occurrence of all 3 species was highest in shrubland because leaf-area index values were lower in shrubland. This high probability of occurrence likely is related to the species' use of open vegetation for foraging. Fire suppression had little effect on projected vegetation composition because as climate changed there was less fuel and burned area. Our results show that if future water limits on plant type are considered, models that incorporate spatial data may suggest how and where different species of birds may respond to vegetation changes. ??2011 Society for Conservation Biology.

  12. A novel combined RNA-protein interaction analysis distinguishes HIV-1 Gag protein binding sites from structural change in the viral RNA leader.

    PubMed

    Kenyon, Julia C; Prestwood, Liam J; Lever, Andrew M L

    2015-01-01

    RNA-protein interactions govern many viral and host cell processes. Conventional 'footprinting' to examine RNA-protein complex formation often cannot distinguish between sites of RNA-protein interaction and sites of RNA structural remodelling. We have developed a novel technique combining photo crosslinking with RNA 2' hydroxyl reactivity ('SHAPE') that achieves rapid and hitherto unachievable resolution of both RNA structural changes and the sites of protein interaction within an RNA-protein complex. 'XL-SHAPE' was validated using well-characterized viral RNA-protein interactions: HIV-1 Tat/TAR and bacteriophage MS2 RNA/Coat Binding Protein. It was then used to map HIV-1 Gag protein interactions on 2D and 3D models of the viral RNA leader. Distinct Gag binding sites were identified on exposed RNA surfaces corresponding to regions identified by mutagenesis as important for genome packaging. This widely applicable technique has revealed a first view of the stoichiometry and structure of the initial complex formed when HIV captures its genome. PMID:26449409

  13. Changes in fluorescent dissolved organic matter upon interaction with anionic surfactant as revealed by EEM-PARAFAC and two dimensional correlation spectroscopy.

    PubMed

    Maqbool, Tahir; Hur, Jin

    2016-10-01

    Surfactants are present in significant amounts in both domestic and industrial wastewater, which may interact with dissolved organic matter (DOM). The present study investigated the interactions of sodium dodecyl sulfate (SDS) with three different DOM solutions, including bovine serum albumin (BSA), humic acid (HA), and the mixture of the two (BSA-HA), based on two advanced spectroscopic tools: excitation emission matrix (EEM) combined with parallel factor analysis (EEM-PARAFAC) and two dimensional correlation spectroscopy (2D-COS). The responses of two protein-like components to the addition of SDS differed depending the presence and the absence of HA. A decreasing and an increasing trend was observed for tryptophan-like (C1) and tyrosine-like (C2) components, respectively, in the BSA solution, while the BSA-HA mixture exhibited increasing fluorescence trends for both protein-like components. The conflicting results suggest that HA plays a secondary role in the protein-SDS interactions. No interaction between the SDS and humic-like component was found. 2D-COS combined with fluorescence spectra demonstrated that the protein-SDS interaction occurred on the order of C2 > C1 for the BSA solution but C1 > C2 for the BSA-HA mixture. Analyses of Scatchard plots confirmed the sequential order interpreted from 2D-COS, showing consistent trends in the binding constants. However, the presence of HA affected the protein-SDS interactions in different manners for C1 and C2, enhancing and reducing the binding constants, respectively. Circular dichroism spectra confirmed the occurrence of conformational changes in BSA with SDS. EEM-PARAFAC and 2D-COS successfully explained different interactions of surfactant with protein-like components in the presence of HA. PMID:27427776

  14. Can genes play a role in explaining frequent job changes? An examination of gene-environment interaction from human capital theory.

    PubMed

    Chi, Wei; Li, Wen-Dong; Wang, Nan; Song, Zhaoli

    2016-07-01

    This study examined how a dopamine genetic marker, DRD4 7 Repeat allele, interacted with early life environmental factors (i.e., family socioeconomic status, and neighborhood poverty) to influence job change frequency in adulthood using a national representative sample from the United States. The dopamine gene played a moderating role in the relationship between early life environments and later job change behaviors, which was meditated through educational achievement. In particular, higher family socioeconomic status was associated with higher educational achievement, and thereafter higher frequency of voluntary job changes and lower frequency of involuntary job changes; such relationships were stronger (i.e., more positive or negative) for individuals with more DRD4 7R alleles. In contrast, higher neighborhood poverty was associated with lower educational achievement, and thereafter lower frequency of voluntary job change and higher frequency of involuntary job change; such relationships were again stronger (i.e., more positive or negative) for individuals with more DRD4 7R alleles. The results demonstrated that molecular genetics using DNA information, along with early life environmental factors, can bring new insights to enhance our understanding of job change frequency in individuals' early career development. (PsycINFO Database Record PMID:27077527

  15. Effects of Stratospheric Ozone Depletion, Solar UV Radiation, and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    EPA Science Inventory

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment...

  16. Conformational changes of DNA in the presence of 12-s-12 gemini surfactants (s=2 and 10). Role of the spacer's length in the interaction surfactant-polynucleotide.

    PubMed

    García, J P; Marrón, E; Martín, V I; Moyá, M L; Lopez-Cornejo, P

    2014-06-01

    A multifaceted study on the interaction of calf-thymus DNA with two different cationic gemini surfactants alkanediyl-α-ω-bis(dodecyldimethyl-amonium)bromide, 12-s-12,2Br(-) (with s=2, G2, and 10, G10) was carried out. The measurements were done at different molar ratios X=[surfactant]/[DNA]. Results show two different conformational changes in DNA: a first compaction of the polynucleotide corresponding to a partial conformational (not total) change of DNA from an extended coil state to a globular state that happens at the lower molar ratio X. A second change corresponds to a breaking of the partial condensation, that is, the transition from the compacted state to a new more extended conformation (for the higher X values) different to the initial extension. According to circular dichroism spectra and dynamic light scattering measurements, this new state of DNA seems to be similar to a ψ-phase. Measurements confirm that interactions involved in the compaction are different to those previously obtained for the analog surfactant CTAB. X values at which the conformational changes happen depend on the length of the spacer in the surfactant along with the charge of the polar heads. PMID:24736044

  17. Electric double-layer interactions in a wedge geometry: Change in contact angle for drops and bubbles

    NASA Astrophysics Data System (ADS)

    Das, Siddhartha; Mitra, Sushanta K.

    2013-09-01

    In this paper, we provide a theory to pinpoint the role of electric double layer (EDL) interactions in governing the contact angle of an electrolyte drop on a charged solid in air or a bubble on a charged surface within an electrolyte solution. The EDL interactions are analytically solved by representing the three phase contact line as a wedge edge, with the wedge being formed by the solid-liquid and the air-liquid interfaces, and calculating the corresponding Maxwell stresses. We demonstrate that the EDL effects induce an “electrowetting-like” behavior, resulting in a lowering of the contact angle. As a specific example, we use this model to analyze the effect of added salt on preformed surface nanobubbles, and find, in contrast to what has been reported earlier, that even for most moderate conditions, added salt may have remarkable effect in altering the contact angle in preformed surface nanobubbles.

  18. Impacts of climate change and variability on tropospheric ozone and its precursors.

    PubMed

    Stevenson, David; Doherty, Ruth; Sanderson, Michael; Johnson, Colin; Collins, Bill; Derwent, Dick

    2005-01-01

    Two coupled climate-chemistry model experiments for the period 1990-2030 were conducted: one with a fixed climate and the other with a varying climate forced by the is92a scenario. By comparing results from these experiments we have attempted to identify changes and variations in physical climate that may have important influences upon tropospheric chemical composition. Climate variables considered include: temperature, humidity, convective mass fluxes, precipitation, and the large-scale circulation. Increases in humidity, directly related to increases in temperature, exert a major influence on the budgets of ozone and the hydroxyl radical: decreasing 03 and increasing OH. Warming enhances decomposition of PAN, releasing NOx, and increases the rate of methane oxidation. Surface warming enhances vegetation emissions of isoprene, an important ozone precursor. In the changed climate, tropical convection generally reduces, but penetrates to higher levels. Over northern continents, convection tends to increase. These changes in convection affect both vertical mixing and lightning NOx emissions. We find no global trend in lightning emissions, but significant changes in its distribution. Changes in precipitation and the large-scale circulation are less important for composition, at least in these experiments. Higher levels of the oxidants OH and H202 lead to increases in aerosol formation and concentrations. These results indicate that climate-chemistry feedbacks are dominantly negative (less 03, a shorter CH4 lifetime, and more aerosol). The major mode of inter-annual variability in the is92a climate experiment is ENSO. This strongly modulates isoprene emissions from vegetation via tropical land surface temperatures. ENSO is also clearly the dominant source of variability in tropical column ozone, mainly through changes in the distribution of convection. The magnitude of inter-annual variability in ozone is comparable to the changes brought about by emissions and climate

  19. Large Frequency Change with Thickness in Interlayer Breathing Mode--Significant Interlayer Interactions in Few Layer Black Phosphorus.

    PubMed

    Luo, Xin; Lu, Xin; Koon, Gavin Kok Wai; Castro Neto, Antonio H; Özyilmaz, Barbaros; Xiong, Qihua; Quek, Su Ying

    2015-06-10

    Bulk black phosphorus (BP) consists of puckered layers of phosphorus atoms. Few-layer BP, obtained from bulk BP by exfoliation, is an emerging candidate as a channel material in post-silicon electronics. A deep understanding of its physical properties and its full range of applications are still being uncovered. In this paper, we present a theoretical and experimental investigation of phonon properties in few-layer BP, focusing on the low-frequency regime corresponding to interlayer vibrational modes. We show that the interlayer breathing mode A(3)g shows a large redshift with increasing thickness; the experimental and theoretical results agree well. This thickness dependence is two times larger than that in the chalcogenide materials, such as few-layer MoS2 and WSe2, because of the significantly larger interlayer force constant and smaller atomic mass in BP. The derived interlayer out-of-plane force constant is about 50% larger than that of graphene and MoS2. We show that this large interlayer force constant arises from the sizable covalent interaction between phosphorus atoms in adjacent layers and that interlayer interactions are not merely of the weak van der Waals type. These significant interlayer interactions are consistent with the known surface reactivity of BP and have been shown to be important for electric-field induced formation of Dirac cones in thin film BP. PMID:25939057

  20. Differential effects of climate and species interactions on range limits at a hybrid zone: potential direct and indirect impacts of climate change.

    PubMed

    McQuillan, Michael A; Rice, Amber M

    2015-11-01

    The relative contributions of climate versus interspecific interactions in shaping species distributions have important implications for closely related species at contact zones. When hybridization occurs within a contact zone, these factors regulate hybrid zone location and movement. While a hybrid zone's position may depend on both climate and interactions between the hybridizing species, little is known about how these factors interact to affect hybrid zone dynamics. Here, we utilize SDM (species distribution modeling) both to characterize the factors affecting the current location of a moving North American avian hybrid zone and to predict potential direct and indirect effects of climate change on future distributions. We focus on two passerine species that hybridize where their ranges meet, the Black-capped (Poecile atricapillus) and Carolina (P. carolinensis) chickadee. Our contemporary climate models predict the occurrence of climatically suitable habitat extending beyond the hybrid zone for P. atricapillus only, suggesting that interspecific interactions primarily regulate this range boundary in P. atricapillus, while climatic factors regulate P. carolinensis. Year 2050 climate models predict a drastic northward shift in suitable habitat for P. carolinensis. Because of the greater importance of interspecific interactions for regulating the southern range limit of P. atricapillus, these climate-mediated shifts in the distribution of P. carolinensis may indirectly lead to a range retraction in P. atricapillus. Together, our results highlight the ways climate change can both directly and indirectly affect species distributions and hybrid zone location. In addition, our study lends support to the longstanding hypothesis that abiotic factors regulate species' poleward range limits, while biotic factors shape equatorial range limits. PMID:26640687

  1. The influence of moisture wound healing on the incidence of bacterial infection and histological changes in healthy human skin after treatment of interactive dressings.

    PubMed

    Koupil, J; Brychta, P; Horký, D; Smola, J; Prásek, J

    2003-01-01

    In this article the authors discuss the problem faced by physicians when trying to use moisture-retentive dressing in pressure sores (decubitus ulcers). First, they report the results of an in vitro study using a new model of experimental wound (radio-isotopic investigation) that assesses the release of Ringer's solution from interactive dressings continually during fourteen hours. Second, they perform an animal experiment that assesses the incidence of wound infection in defects treated conventionally or using interactive dressings. The defects treated with interactive pads had lower incidence of wound infection, and the process of wound healing was rapid. Finally, the authors discuss their experience in four paraplegic patients with decubitus ulcers where they used moisture-retentive dressing on ulcers and on the surrounding intact skin before surgical procedure to detect the possibility of maceration of healthy skin. Histological evaluation was performed in order to find microscopically changes after moisture healing. The changes of healthy skin were not significant after treatment of moisture-retentive dressings. PMID:14733252

  2. Presentation of the FMI 5000 Project: Environmental changes: Fluvio-marine interactions over the last 5000yrs

    NASA Astrophysics Data System (ADS)

    Ramos-Pereira, Ana; Ramos, Catarina; Trindade, Jorge; Araújo-Gomes, João.; Rocha, Jorge; Granja, Helena; Gonçalves, Luís.; Monge-Soares, António; Martins, José

    2010-05-01

    Keywords: Estuaries, Environmental Changes, Holocene, GIS Modelling, Portugal FMI 5000 Project (between 2010 and 2012) aims to evaluate, in different estuarine environmental conditions, the balance between fluvial and marine influences, the responses to climatic events and the impact of land use changes. The temporal window chosen, contains different trends of the sea level, climatic fluctuations like the Bond events or humid episodes recorded in the Iberian Peninsula, as well as the increase of the human intervention in the landscape, particularly sensitive since the Bronze Age (circa 3500yr), imprinted in the filling-up of the alluvial plain estuaries. The Portuguese mainland mesotidal coast spreads out in two different environmental conditions: (i) the West coast exposed to the NW dominant waves, with a temperate oceanic climate and fluvial regimes and (ii) the Southern sheltered one, but open to the SW storms, with a Mediterranean climate and with occasional heavy fluvial discharges. This contrast along the coast creates a good field of research to achieve the aims of the project. To prosecute this goal, estuaries of medium drainage basins were selected as they have homogeneous climate, geologic and geomorphologic conditions, allowing to define accurately the hydroclimatic events that contribute to the infilling of the estuarine plains. The small changes are recorded not only in the textural properties of the sediments, already recognized in the sediments of the Tagus and Guadiana rivers and in the small estuaries of the Spanish southern coast but also in the micro fauna, pollens and non-pollen-palinomorphs allowing to define the environmental changes, both marine and fluvial. To achieve the Project goals we select three estuaries in different climatic and wave climate conditions, to develop four different kinds of research and methodologies: (i) To identify millenary evolution, several hand-operated gauge auger cores or vibracores will be carried out in the

  3. Interaction of collagen-like peptide models of asymmetric acetylcholinesterase with glycosaminoglycans: spectroscopic studies of conformational changes and stability.

    PubMed

    Doss-Pepe, E; Deprez, P; Inestrosa, N C; Brodsky, B

    2000-12-01

    The effect of heparin on the conformation and stability of triple-helical peptide models of the collagen tail of asymmetric acetylcholinesterase expands our understanding of heparin interactions with proteins and presents an opportunity for clarifying the nature of binding of ligands to collagen triple-helix domains. Within the collagen tail of AChE, there are two consensus sequences for heparin binding of the form BBXB, surrounded by additional basic residues. Circular dichroism studies were used to determine the effect of the addition of increasing concentrations of heparin on triple-helical peptide models for the heparin binding domains, including peptides in which the basic residues within and surrounding the consensus sequence were replaced by alanine residues. The addition of heparin caused an increased triple-helix content with saturation properties for the peptide modeling the C-terminal site, while precipitation, with no increased helix content resulted from heparin addition to the peptide modeling the N-terminal site. The results suggest that the two binding sites with a similar triple-helical conformation have distinctive ways of interacting with heparin, which must relate to small differences in the consensus sequence (GRKGR vs GKRGK) and in the surrounding basic residues. Addition of heparin increased the thermal stability of all peptides containing the consensus sequence. Heparan sulfate produced conformational and stabilization effects similar to those of heparin, while chondroitin sulfate led to a cloudy solution, loss of circular dichroism signal, and a smaller increase in thermal stability. Thus, specificity in both the sequence of the triple helix and the type of glycosaminoglycan is required for this interaction. PMID:11101304

  4. Response of an interactive two-dimensional model to ozone changes - An estimate of the radiative dynamical feedback effect

    NASA Technical Reports Server (NTRS)

    Schneider, Hans R.; Ko, Malcolm K. W.

    1990-01-01

    The response of the interactive two-dimensional stratospheric model described by Schneider et al. (1989) to an increased chemical removal of ozone and the sensitivity of the calculated assessments to the choice of eddy diffusion coefficients are investigated using a simplified ozone chemistry model. It was found that the radiative dynamical feedback in the model leads to ozone losses at high altitudes to be about one third smaller than predicted by a model with fixed temperature and circulation. The radiative feedback has a smaller effect on ozone (losses decrease by about one sixth) in the lower stratosphere. Predicted ozone losses increase with decreasing dissipation and eddy diffusion in the lower stratosphere.

  5. The interactive effect of change in perceived stress and trait anxiety on vagal recovery from cognitive challenge.

    PubMed

    Crowley, Olga V; McKinley, Paula S; Burg, Matthew M; Schwartz, Joseph E; Ryff, Carol D; Weinstein, Maxine; Seeman, Teresa E; Sloan, Richard P

    2011-12-01

    The present study tested the hypothesis that the change in state negative affect (measured as perceived stress) after cognitive challenge moderates the relationship of trait anxiety and anger to vagal recovery from that challenge. Cardiac vagal control (assessed using heart rate variability) and respiratory rate were measured in a sample of 905 participants from the Midlife in the United States Study. Cognitive challenges consisted of computerized mental arithmetic and Stroop color-word matching tasks. Multiple regression analyses controlling for the effects of the demographic, lifestyle, and medical factors influencing cardiac vagal control showed a significant moderating effect of change in perceived stress on the relationship of trait anxiety to vagal recovery from cognitive challenges (Beta=.253, p=.013). After adjustment for respiratory rate, this effect became marginally significant (Beta=.177, p=.037). In contrast, for the relationship of trait anger to vagal recovery, this effect was not significant either before (Beta=.141, p=.257) or after (Beta=.186, p=.072) adjusting for respiratory rate. Secondary analyses revealed that among the individuals with higher levels of trait anxiety, greater reductions in perceived stress were associated with greater increases in cardiac vagal control after the challenge. In contrast, among the individuals with lower levels of trait anxiety, changes in perceived stress had no impact on vagal recovery. Therefore, change in perceived stress moderates the relationship of trait anxiety, but not trait anger, to vagal recovery from cognitive challenge. PMID:21945037

  6. A Pathway-based Approach to Predicting Interactions between Chemical and Non-chemical Stressors: Applications to Global Climate Change

    EPA Science Inventory

    A variety of environmental variables influenced by global climate change (GCC) can directly or indirectly affect the health of organisms. These variables may include temperature, salinity, pH, and penetration of ultraviolet radiation (UVR) in aquatic environments, and water shor...

  7. Gender and Age Effects Interact in Preschoolers' Help-Seeking: Evidence for Differential Responses to Changes in Task Difficulty

    ERIC Educational Resources Information Center

    Thompson, R. Bruce; Cothran, Thomas; McCall, Daniel

    2012-01-01

    This study explored preschool age and gender differences in help-seeking within the theoretical framework of scaffolded problem-solving and self-regulation (Bruner, 1986; Rogoff, 1990; Vygotsky, 1978; 1986). Within-subject analyses tracked changes in help-seeking among 62 preschoolers (34 boys, 28 girls, mean age 4.22 years) solving a challenging…

  8. Interaction of ENSO-driven flood variability and anthropogenic changes driving river channel evolution: Corryong Creek, Australia

    NASA Astrophysics Data System (ADS)

    Teo, Elisha; Marren, Philip

    2014-05-01

    River channels are highly responsive to climatic forcing, particularly in terms of changes in flow regime. Variability in precipitation can directly alter channel dimensions via erosion and deposition, particularly in response to prolonged droughts or extreme floods, but also alter channel stability through changes in catchment and riparian vegetation, which create complex feedback mechanisms which can reinforce relatively modest climate changes. In Australia, short-term hydrological precipitation is largely driven by changes to the El Nino-Southern Oscillation cycle. A body of research also suggests that river channels respond to longer term (40-50 year) alternating flood and drought dominated regimes. In this study, we determine the role of climate forcing in controlling the channel shape and stability of Corryong Creek, a dynamic gravel-bed river in southeast Australia, using a range of climate, hydrological, geomorphological and historic data. Corryong Creek is highly response to ENSO scale hydrological variability, with a distinct pattern of channel narrowing and stabilisation by vegetation during El Nino periods, and significant, often catastrophic widening during La Nina phases, usually associated with a rapid succession of high magnitude floods. There is no evidence of longer flood or drought dominated regimes, either statistically, in the hydrological record, or in terms of a geomorphological signature. Major bushfires (which have occurred in 1939 and 2003) occur during or toward the end of dry phases, but produce a short live increase in flood erosion, due to increased runoff and the destruction of riparian vegetation. However, long-term (100 year) changes have been heavily mediated by anthropogenic activities. The most dramatic change to the channel is a significant reduction in sinuosity, which occurred rapidly in the early to mid 20th century, associated with clearing of all floodplain and riparian vegetation, and major clearing of the lower hillslopes

  9. Interactions between climate change impacts on forest productivity and mortality and stream water quality in the US Western Mountains (Invited)

    NASA Astrophysics Data System (ADS)

    Tague, C.; Zhu, J.

    2013-12-01

    In the snow-dominated mountains of the Western US, climate change is likely to alter forest productivity, water use and nutrient uptake. The consequence of changes in forest structure and function will have impacts on both water quality and water quantity. Warmer temperatures, reduced snow accumulation and earlier melt, elevated CO2 and increased frequency and severity of drought all influence forest productivity, sometimes in opposing ways. In the complex topography of mountain environments, whether forest productivity increases or decreases is likely to vary along gradients between water and energy limited systems. Implications for forest structure also vary along these gradients, and include the impact of disturbances such as fire and pests. We build on earlier work that used a coupled eco-hydrologic model to show how forest water use changes with increasing temperatures and how these changes are distributed along elevational gradients for a snow-dominated site within the California Sierra. We extend this analysis to investigate associated changes in forest structure and nutrient uptake with temperature warming, along an elevational gradient. We compare results for sites in the California Sierra and the wetter Pacific Northwest. Results show that for wetter sites, forest productivity is likely to increases with associated declines in stream nutrient export. For drier sites, however, forest productivity may decline leading to reduced forest nutrient uptake. This decline in uptake is combined with shifts to more winter rainfall that together may facilitate greater flushing of nutrients. We use these results to define scenarios where we would expect forest productivity to decline and lead to increase nitrate leaching to stream and groundwater.

  10. PI(4)P Promotes Phosphorylation and Conformational Change of Smoothened through Interaction with Its C-terminal Tail.

    PubMed

    Jiang, Kai; Liu, Yajuan; Fan, Junkai; Zhang, Jie; Li, Xiang-An; Evers, B Mark; Zhu, Haining; Jia, Jianhang

    2016-02-01

    In Hedgehog (Hh) signaling, binding of Hh to the Patched-Interference Hh (Ptc-Ihog) receptor complex relieves Ptc inhibition on Smoothened (Smo). A longstanding question is how Ptc inhibits Smo and how such inhibition is relieved by Hh stimulation. In this study, we found that Hh elevates production of phosphatidylinositol 4-phosphate (PI(4)P). Increased levels of PI(4)P promote, whereas decreased levels of PI(4)P inhibit, Hh signaling activity. We further found that PI(4)P directly binds Smo through an arginine motif, which then triggers Smo phosphorylation and activation. Moreover, we identified the pleckstrin homology (PH) domain of G protein-coupled receptor kinase 2 (Gprk2) as an essential component for enriching PI(4)P and facilitating Smo activation. PI(4)P also binds mouse Smo (mSmo) and promotes its phosphorylation and ciliary accumulation. Finally, Hh treatment increases the interaction between Smo and PI(4)P but decreases the interaction between Ptc and PI(4)P, indicating that, in addition to promoting PI(4)P production, Hh regulates the pool of PI(4)P associated with Ptc and Smo. PMID:26863604

  11. PI(4)P Promotes Phosphorylation and Conformational Change of Smoothened through Interaction with Its C-terminal Tail

    PubMed Central

    Zhang, Jie; Li, Xiang-An; Evers, B. Mark; Zhu, Haining; Jia, Jianhang

    2016-01-01

    In Hedgehog (Hh) signaling, binding of Hh to the Patched-Interference Hh (Ptc-Ihog) receptor complex relieves Ptc inhibition on Smoothened (Smo). A longstanding question is how Ptc inhibits Smo and how such inhibition is relieved by Hh stimulation. In this study, we found that Hh elevates production of phosphatidylinositol 4-phosphate (PI(4)P). Increased levels of PI(4)P promote, whereas decreased levels of PI(4)P inhibit, Hh signaling activity. We further found that PI(4)P directly binds Smo through an arginine motif, which then triggers Smo phosphorylation and activation. Moreover, we identified the pleckstrin homology (PH) domain of G protein-coupled receptor kinase 2 (Gprk2) as an essential component for enriching PI(4)P and facilitating Smo activation. PI(4)P also binds mouse Smo (mSmo) and promotes its phosphorylation and ciliary accumulation. Finally, Hh treatment increases the interaction between Smo and PI(4)P but decreases the interaction between Ptc and PI(4)P, indicating that, in addition to promoting PI(4)P production, Hh regulates the pool of PI(4)P associated with Ptc and Smo. PMID:26863604

  12. Electron spin resonance of interacting spins in n-Ge: II. Change in the width and shape of lines

    SciTech Connect

    Veinger, A. I.; Zabrodskii, A. G.; Tisnek, T. V. Goloshchapov, S. I.

    2008-11-15

    The effect of spin interaction on the width and shape of the electron spin resonance line in compensated and uncompensated n-Ge:As has been studied. It is shown that, in the case of a magnetic field oriented along the [100] axis, the width of the resonance line decreases irrespective of the degree of compensation as the critical concentration of the insulator-metal transition is approached, owing to enhancement of the exchange interaction of spins and to an increase in the spin relaxation time. When the magnetic field is directed along other axes, an additional line broadening appears in compensated samples. This broadening is determined by the influence exerted on the g factor by fluctuations of the internal electrostatic field via the stresses generated by these fluctuations. For well-conducting samples, in which the thickness of the skin layer becomes smaller than that of the sample, the line takes on an asymmetric (Dysonian) shape. In this case, the ratio between the wings of the derivative, characteristic of this line shape, is determined by the ratio between the rates of spin diffusion and spin relaxation.

  13. Specific Inter-residue Interactions as Determinants of Human Monoacylglycerol Lipase Catalytic Competency: A ROLE FOR GLOBAL CONFORMATIONAL CHANGES.

    PubMed

    Tyukhtenko, Sergiy; Karageorgos, Ioannis; Rajarshi, Girija; Zvonok, Nikolai; Pavlopoulos, Spiro; Janero, David R; Makriyannis, Alexandros

    2016-02-01

    The serine hydrolase monoacylglycerol lipase (MGL) functions as the main metabolizing enzyme of 2-arachidonoyl glycerol, an endocannabinoid signaling lipid whose elevation through genetic or pharmacological MGL ablation exerts therapeutic effects in various preclinical disease models. To inform structure-based MGL inhibitor design, we report the direct NMR detection of a reversible equilibrium between active and inactive states of human MGL (hMGL) that is slow on the NMR time scale and can be modulated in a controlled manner by pH, temperature, and select point mutations. Kinetic measurements revealed that hMGL substrate turnover is rate-limited across this equilibrium. We identify a network of aromatic interactions and hydrogen bonds that regulates hMGL active-inactive state interconversion. The data highlight specific inter-residue interactions within hMGL modulating the enzymes function and implicate transitions between active (open) and inactive (closed) states of the hMGL lid domain in controlling substrate access to the enzymes active site. PMID:26555264

  14. Spatial and environmental components of evolutionary change: interactive effects of salinity and temperature on Fucus vesiculosus as an example

    NASA Astrophysics Data System (ADS)

    Russell, G.

    1987-09-01

    Intertidal algae experience aerial temperatures as well as those of ambient seawater and, during their periods of emergence, are subject to considerable variation in salinity. The eastern Atlantic distribution of Fucus vesiculosus L. (Phaeophyta) lies within the 5° and 20° August isotherms. Experiments indicate that this plant can survive temperatures above and below these at normal salinity (34‰). However, at extreme temperatures it is evidently much more susceptible to saline changes than at those of the limiting isotherms. Thus the temperature limits for surviving acute saline change appear to give a better biogeographical fit than temperature alone. Nevertheless, the presence of F. vesiculosus in estuaries at or near both geographical limits is inconsistent with the experimental results obtained from British plants. Some population divergence may therefore have occurred.

  15. The interacting winds of Eta Carinae: Observed forbidden line changes and the Forbidden Blue(-Shifted) Crab

    NASA Astrophysics Data System (ADS)

    Gull, Theodore R.; Madura, Thomas; Corcoran, Michael F.; Teodoro, Mairan; Richardson, Noel; Hamaguchi, Kenji; Groh, Jose H.; Hillier, Desmond John; Damineli, Augusto; Weigelt, Gerd

    2015-01-01

    The massive binary, Eta Carinae (EC), produces such massive winds that strong forbidden line emission of singly- and doubly-ionized iron traces wind-wind interactions from the current cycle plus fossil interactions from one, two and three 5.54-year cycles ago.With an eccentricity of >0.9, the >90 solar mass primary (EC-A) and >30 solar mass secondary (EC-B) approach to within 1.5 AU during periastron and recede to nearly 30 AU across apastron. The wind-wind structures move outward driven by the 420 km/s primary wind interacting with the ~3000 km/s secondary wind yielding partially-accelerated compressed primary wind shells that are excited by mid-UV from EC-A and in limited lines of sight, FUV from EC-B.These structures are spectroscopically and spatially resolved by HST's Space Telescope Imaging Spectrograph. At critical binary phases, we have mapped the central 2'x2' region in the light of [Fe III] and [Fe II] with spatial resolution of 0.12' and velocity resolution of 40 km/s.1) The bulk of forbidden emission originates from the large cavity northwest of EC and is due to ionization of massive ejecta from the 1840s and 1890s eruptions. The brightest clumps are the Weigelt Blobs C and D, but there are additionally multiple, fainter emission clumps. Weigelt B appears to have faded.2) Three concentric, red-shifted [FeII] arcs expand at ~470 km/s excited by mid-UV of EC-A.3) The structure of primarily blue-shifted [Fe III] emission resembles a Maryland Blue Crab. The claws appear at the early stages of the high-excitation recovery from the periastron passage, expand at radial velocities exceeding the primary wind terminal velocity, 420 km/s and fade as the binary system approaches periastron with the primary wind enveloping the FUV radiation from EC-B.4) All [Fe III] emission faded by late June 2014 and disappeared by August 2, 2014, the beginning of periastron passage.Comparisons to HST/STIS observations between 1998 to 2004.3 indicate long-term fading of [Fe II

  16. The interactions of the cells in the development of osteoporotic changes in bones under space flight conditions

    NASA Astrophysics Data System (ADS)

    Rodionova, Natalia; Kabitskaya, Olga

    2016-07-01

    Using the methods of electron microscopy and autoradiography with ³N-glycine and ³N-thymidine on biosatellites "Bion-11" (Macaca mulatta, the duration of the experiments -10 days), "Bion-M1" (mouse C57 Black, duration of the flight - 30 days) in the experiments with modeled hypokinesia (white rats, hind limbs unloading, the duration of the experiments 28 days) new data about the morpho-functional peculiarities of cellular interactions in adaptive remodeling zones of bone structures under normal conditions and after exposure of animals to microgravity. Our conception on remodeling proposes the following sequence in the development of cellular interactions after decrease of the mechanical loading: a primary response of osteocytes (mechanosensory cells) to the mechanical stimulus; osteocytic remodeling (osteolysis); transmission of the mechanical signals through a system of canals and processes to functionally active osteoblasts and paving endost one as well as to the bone-marrow stromal cells and perivascular cells. As a response to the mechanical stimulus (microgravity) the system of perivascular cell-stromal cell-preosteoblast-osteoblast shows a delay in proliferation, differentiation and specific functioning of the osteogenetic cells, the number of apoptotic osteoblasts increases. Then the osteoclastic reaction occurs (attraction of monocytes and formation of osteoclasts, bone matrix resorption in the loci of apoptosis of osteoblasts and osteocytes). The macrophagal reaction is followed by osteoblastogenesis, which appears to be a rehabilitating process. However, during prolonged absence of mechanical stimuli (microgravity, long-time immobilization) the adaptive activization of osteoblastogenesis doesn't occur (as it is the case during the physiological remodeling of bone tissue) or it occurs to a smaller degree. The loading deficit leads to an adaptive differentiation of stromal cells to fibroblastic cells and adipocytes in remodeling loci. These cell reactions

  17. Modeled Northern Hemisphere ice-sheet-climate interactions and contributions to sea-level change since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Heinemann, M.; Timmermann, A.; Elison Timm, O.; Saito, F.; Abe-Ouchi, A.

    2013-12-01

    One of the most recent massive climate change events in earth's history was the last glacial termination 19-9 thousand years before present (ka BP). Northern Hemisphere ice-sheets receded quickly, causing global sea level to rise by more than 100 m, meltwater was injected into the North Atlantic halting its deepwater formation, atmospheric CO2 concentrations rose by almost 100 ppmv, and the global surface warmed by about 4°C. It is still unresolved what exactly caused this deglacial climate change and ice sheet melting. To address this question, we set out to conduct a series of transient modeling experiments with a coupled 3-dimensional ice-sheet-climate model (iLove). The model includes atmosphere-ocean-sea ice-vegetation components of the intermediate complexity model LOVECLIM and uses bi-directional coupling to the ice-sheet model IcIES. Supporting Milankovitch theory, our results indicate that the deglaciation was initiated by orbital parameter changes. However, according to our model, rising CO2 concentrations after 17 ka BP accelerated the deglaciation. Without this deglacial CO2 increase, large parts of North America and Scandinavia would be covered by ice sheets today. Present sea level would be as much as 100 m lower, and still dropping by about 2.5 m per thousand years due to growing ice sheets. Despite the deglacial CO2-rise and global warming of 4°C, the simulated Greenland ice-sheet only looses about 25% of its volume during the deglaciation, and grows again in the Holocene after 8 ka BP at a rate of about 0.1 m sea level equivalent per thousand years. Our results indicate that the stability of the Greenland ice sheet during the deglaciation and Holocene is supported by changes of the atmospheric stationary wave pattern, and by the deglacial sea ice retreat.

  18. The Response of Subalpine Vegetation to Climate Change and Bark Beetle Infestations: A Multi-Scale Interaction.

    NASA Astrophysics Data System (ADS)

    Foster, A.; Shuman, J. K.; Shugart, H. H., Jr.; Negrón, J. F.

    2015-12-01

    Mean annual temperatures in the western United States have increased in the last few decades, and are predicted to continue warming. In the subalpine zone of the Rocky Mountains, this warming is also predicted to increase the frequency and severity of spruce beetle outbreaks. Climate change itself may affect this vegetation, potentially leading to shifts in species compositions. These forests are a crucial part of the US's carbon budget, thus it is important to analyze how climate change and bark beetles in conjunction will affect the biomass and species composition of vegetation in subalpine zone. UVAFME is an individual-based gap model that simulates biomass and species composition of a forest. This model has been quantitatively tested at various Rocky Mountain sites in the Front Range, and has been shown to accurately simulate the vegetation dynamics in the region. UVAFME has been updated with a spruce beetle subroutine that calculates the probability for beetle infestation of each tree on a plot. This probability is based on site, climate, and individual tree characteristics, such as temperature; stand structure; and tree stress level, size, and age. These governing characteristics are based on data from the US Forest Service, and other studies on spruce susceptibility and spruce beetle phenology. UVAFME is then run with multiple climate change and beetle scenarios to determine the net effect of both variables on subalpine vegetation. These results are compared among the different scenarios and to current forest inventory data. We project that increasing temperatures due to climate change will cause an increase in the frequency and severity of spruce beetle outbreaks, leading to a decrease in the biomass and dominance of Engelmann spruce. These results are an important step in understanding the possible futures for the vegetation of subalpine zone in the Rocky Mountains.

  19. The interactive effects of excess reactive nitrogen and climate change on aquatic ecosystems and water resources of the United States

    USGS Publications Warehouse

    Baron, J.S.; Hall, E.K.; Nolan, B.T.; Finlay, J.C.; Bernhardt, E.S.; Harrison, J.A.; Chan, F.; Boyer, E.W.

    2012-01-01

    Nearly all freshwaters and coastal zones of the US are degraded from inputs of excess reactive nitrogen (Nr), sources of which are runoff, atmospheric N deposition, and imported food and feed. Some major adverse effects include harmful algal blooms, hypoxia of fresh and coastal waters, ocean acidification, long-term harm to human health, and increased emissions of greenhouse gases. Nitrogen fluxes to coastal areas and emissions of nitrous oxide from waters have increased in response to N inputs. Denitrification and sedimentation of organic N to sediments are important processes that divert N from downstream transport. Aquatic ecosystems are particularly important denitrification hotspots. Carbon storage in sediments is enhanced by Nr, but whether carbon is permanently buried is unknown. The effect of climate change on N transport and processing in fresh and coastal waters will be felt most strongly through changes to the hydrologic cycle, whereas N loading is mostly climate-independent. Alterations in precipitation amount and dynamics will alter runoff, thereby influencing both rates of Nr inputs to aquatic ecosystems and groundwater and the water residence times that affect Nr removal within aquatic systems. Both infrastructure and climate change alter the landscape connectivity and hydrologic residence time that are essential to denitrification. While Nr inputs to and removal rates from aquatic systems are influenced by climate and management, reduction of N inputs from their source will be the most effective means to prevent or to minimize environmental and economic impacts of excess Nr to the nation’s water resources.

  20. Commentary on "Spectral characterization of the binding and conformational changes of serum albumins upon interaction with an anticancer drug, anastrozole"

    NASA Astrophysics Data System (ADS)

    Korkmaz, Filiz

    2015-03-01

    The manuscript by R. Punith and J. Seetharamappa (http://dx.doi.org/10.1016/j.saa.201202.038) presents the interaction between serum albumin from human (HAS) and from bovine (BSA) with a drug called Anastrozole (AZ). The drug is on the market for treating patients with breast cancer after surgery and for metastasis in women. The study utilizes various spectroscopic techniques such as; fluorescence, synchronous fluorescence, 3D fluorescence measurements, FTIR, CD and UV. Although there are some relatively minor comments on the paper, the main point that needs to be reviewed by the authors is the result of FTIR measurements. Based on the data provided in the text (there is no figure), the protein sample is not in its native state, which makes the data inconvenient to be used in drawing conclusions. Authors are kindly requested to take another look at the FTIR experiments.

  1. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Astrophysics Data System (ADS)

    Stevenson, D. S.; Young, P. J.; Naik, V.; Lamarque, J.-F.; Shindell, D. T.; Voulgarakis, A.; Skeie, R. B.; Dalsoren, S. B.; Myhre, G.; Berntsen, T. K.; Folberth, G. A.; Rumbold, S. T.; Collins, W. J.; MacKenzie, I. A.; Doherty, R. M.; Zeng, G.; van Noije, T. P. C.; Strunk, A.; Bergmann, D.; Cameron-Smith, P.; Plummer, D. A.; Strode, S. A.; Horowitz, L.; Lee, Y. H.; Szopa, S.; Sudo, K.; Nagashima, T.; Josse, B.; Cionni, I.; Righi, M.; Eyring, V.; Conley, A.; Bowman, K. W.; Wild, O.; Archibald, A.

    2013-03-01

    Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP) scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 410 mW m-2. The model range of pre-industrial to present-day changes in O3 produces a spread (±1 standard deviation) in RFs of ±17%. Three different radiation schemes were used - we find differences in RFs between schemes (for the same ozone fields) of ±10%. Applying two different tropopause definitions gives differences in RFs of ±3%. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of ±30% for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44±12%), nitrogen oxides (31 ± 9%), carbon monoxide (15 ± 3%) and non-methane volatile organic compounds (9 ± 2%); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m-2 DU-1, a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m-2; relative to 1750) for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) of 350, 420, 370 and 460 (in 2030), and 200, 300, 280 and 600 (in 2100). Models show some coherent responses of ozone to climate change: decreases in the

  2. Tropospheric Ozone Changes, Radiative Forcing and Attribution to Emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Technical Reports Server (NTRS)

    Stevenson, D.S.; Young, P.J.; Naik, V.; Lamarque, J.-F.; Shindell, D. T.; Voulgarakis, A.; Skeie, R. B.; Dalsoren, S. B.; Myhre, G.; Berntsen, T. K.; Folberth, G. A.; Rumbold, S. T.; Collins, W. J.; MacKenzie, I. A.; Doherty, R. M.; Zeng, G.; vanNoije, T. P. C.; Strunk, A.; Bergmann, D.; Cameron-Smith, P.; Plummer, D. A.; Strode, S. A.; Horowitz, L.; Lee, Y. H.; Szopa, S.; Sudo, K.; Nagashima, T.; Josse, B.; Cionni, I.; Righi, M.; Eyring, V.; Conley, A.; Bowman, K. W.; Wild, O.; Archibald, A.

    2013-01-01

    Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP) scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 410 mW m-2. The model range of pre-industrial to present-day changes in O3 produces a spread (+/-1 standard deviation) in RFs of +/-17%. Three different radiation schemes were used - we find differences in RFs between schemes (for the same ozone fields) of +/-10 percent. Applying two different tropopause definitions gives differences in RFs of +/-3 percent. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of +/-30 percent for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44+/-12 percent), nitrogen oxides (31 +/- 9 percent), carbon monoxide (15 +/- 3 percent) and non-methane volatile organic compounds (9 +/- 2 percent); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m(-2) DU(-1), a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m(-2); relative to 1750) for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) of 350, 420, 370 and 460 (in 2030), and 200, 300, 280 and 600 (in 2100). Models show some

  3. Transient changes in electric fields induced by interaction of ultraintense laser pulses with insulator and metal foils: Sustainable fields spanning several millimeters

    NASA Astrophysics Data System (ADS)

    Inoue, Shunsuke; Tokita, Shigeki; Hashida, Masaki; Sakabe, Shuji

    2015-04-01

    The temporal evolutions of electromagnetic fields generated by the interaction between ultraintense lasers (1.3 ×1018 and 8.2 ×1018W /c m2 ) and solid targets at a distance of several millimeters from the laser-irradiated region have been investigated by electron deflectometry. For three types of foil targets (insulating foil, conductive foil, and insulating foil onto which a metal disk was deposited), transient changes in the fields were observed. We found that the direction, strength, and temporal evolution of the generated fields differ markedly for these three types of targets. The results provide an insight for studying the emission dynamics of laser-accelerated fast electrons.

  4. In Search of the E. coli Compounds that Change the Antibiotic Production Pattern of Streptomyces coelicolor During Inter-species Interaction.

    PubMed

    Mavituna, Ferda; Luti, Khalid Jaber Kadhum; Gu, Lixing

    2016-08-01

    The aim of this work was to investigate the interaction between E.coli and Streptomyces coelicolor A3 (2) for the increased production of undecylprodigiosin and identify the E. coli actives mediating this inter-species interaction. The antibiotics of interest were the red-pigmented undecylprodigiosin and blue-pigmented actinorhodin. Pure cultures of S. coelicolor in a defined medium produced higher concentrations of actinorhodin compared to those of undecylprodigiosin. The latter however, is more important due to its immunosuppressive and antitumor properties. As a strategy to increase undecylprodigiosin production, we added separately, live cells and heat-killed cells of E. coli C600, and the cell-free supernatant of E. coli culture to S. coelicolor cultures in shake flasks. The interaction with live cells of E. coli altered the antibiotic production pattern and undecylprodigiosin production was enhanced by 3.5-fold compared to the pure cultures of S. coelicolor and actinorhodin decreased by 15-fold. The heat-killed cells of E. coli however, had no effect on antibiotic production. In all cases, growth and glucose consumption of S. coelicolor remained almost the same as those observed in the pure culture indicating that the changes in antibiotic production were not due to nutritional stress. Results with cell-free supernatant of E. coli culture indicated that the interaction between S. coelicolor and E. coli was mediated via diffusible molecule(s). Using a set of extraction procedures and agar-well diffusion bioassays, we isolated and preliminarily identified a class of compounds. For the preliminary verification, we added the compound which was the common chemical structural moiety in this class of compounds to the pure S. coelicolor cultures. We observed similar effects on antibiotic production as with the live E. coli cells and their supernatant indicating that this class of compounds secreted by E. coli indeed could act as actives during interspecies

  5. Antibiotic-induced dysbiosis alters host-bacterial interactions and leads to colonic sensory and motor changes in mice.

    PubMed

    Aguilera, M; Cerdà-Cuéllar, M; Martínez, V

    2015-01-01

    Alterations in the composition of the commensal microbiota (dysbiosis) seem to be a pathogenic component of functional gastrointestinal disorders, mainly irritable bowel syndrome (IBS), and might participate in the secretomotor and sensory alterations observed in these patients.We determined if a state antibiotics-induced intestinal dysbiosis is able to modify colonic pain-related and motor responses and characterized the neuro-immune mechanisms implicated in mice. A 2-week antibiotics treatment induced a colonic dysbiosis (increments in Bacteroides spp, Clostridium coccoides and Lactobacillus spp and reduction in Bifidobacterium spp). Bacterial adherence was not affected. Dysbiosis was associated with increased levels of secretory-IgA, up-regulation of the antimicrobial lectin RegIIIγ, and toll-like receptors (TLR) 4 and 7 and down-regulation of the antimicrobial-peptide Resistin-Like Molecule-β and TLR5. Dysbiotic mice showed less goblet cells, without changes in the thickness of the mucus layer. Neither macroscopical nor microscopical signs of inflammation were observed. In dysbiotic mice, expression of the cannabinoid receptor 2 was up-regulated, while the cannabinoid 1 and the mu-opioid receptors were down-regulated. In antibiotic-treated mice, visceral pain-related responses elicited by intraperitoneal acetic acid or intracolonic capsaicin were significantly attenuated. Colonic contractility was enhanced during dysbiosis. Intestinal dysbiosis induce changes in the innate intestinal immune system and modulate the expression of pain-related sensory systems, an effect associated with a reduction in visceral pain-related responses. Commensal microbiota modulates gut neuro-immune sensory systems, leading to functional changes, at least as it relates to viscerosensitivity. Similar mechanisms might explain the beneficial effects of antibiotics or certain probiotics in the treatment of IBS. PMID:25531553

  6. Impact of climate change on human-wildlife-ecosystem interactions in the Trans-Himalaya region of Nepal

    NASA Astrophysics Data System (ADS)

    Aryal, Achyut; Brunton, Dianne; Raubenheimer, David

    2014-02-01

    The Trans-Himalaya region boasts an immense biodiversity which includes several threatened species and supports the livelihood of local human populations. Our aim in this study was to evaluate the impact of recent climate change on the biodiversity and human inhabitants of the upper Mustang region of the Trans-Himalaya, Nepal. We found that the average annual temperature in the upper Mustang region has increased by 0.13 °C per year over the last 23 years; a higher annual temperature increase than experienced in other parts of Himalaya. A predictive model suggested that the mean annual temperature will double by 2161 to reach 20 °C in the upper Mustang region. The combined effects of increased temperature and diminished snowfall have resulted in a reduction in the area of land suitable for agriculture. Most seriously affected are Samjung village (at 4,100 m altitude) and Dhey village (at 3,800 m) in upper Mustang, where villagers have been forced to relocate to an area with better water availability. Concurrent with the recent change in climate, there have been substantial changes in vegetation communities. Between 1979 and 2009, grasslands and forests in the Mustang district have diminished by 11 and 42 %, respectively, with the tree line having shifted towards higher elevation. Further, grasses and many shrub species are no longer found in abundance at higher elevations and consequently blue sheep ( Pseduois nayaur) move to forage at lower elevations where they encounter and raid human crops. The movement of blue sheep attracts snow leopard ( Panthera uncia) from their higher-elevation habitats to lower sites, where they encounter and depredate livestock. Increased crop raiding by blue sheep and depredations of livestock by snow leopard have impacted adversely on the livelihoods of local people.

  7. Differential changes and interactions of autonomic functioning and sleep architecture before and after 50 years of age.

    PubMed

    Kuo, T B J; Li, Jia-Yi; Kuo, Hsu-Ko; Chern, Chang-Ming; Yang, C C H

    2016-02-01

    We hypothesize that the time when age-related changes in autonomic functioning and in sleep structure occur are different and that autonomic functioning modulates sleep architecture differently before and after 50 years of age. Sixty-eight healthy subjects (aged 20 to 79 years old, 49 of them women) were enrolled. Correlation analysis revealed that wake after sleep onset, the absolute and relative value of stage 1 (S1; S1%), and relative value of stage 2 (S2) were positively correlated with age; however, sleep efficiency, stage 3 (S3), S3%, and rapid-eye-movement latency (REML) were negatively correlated with age. Significant degenerations of sleep during normal aging were occurred after 50 years of age; however, significant declines of autonomic activity were showed before 50 years of age. Before 50 years of age, vagal function during sleep was negatively correlated with arousal index; however, after 50 years of age, it was positively correlated with S1 and S1%. In addition, sympathetic activity during wake stage was positively related to S2% only after 50 years of age. Our results imply that the age-related changes in autonomic functioning decline promptly as individuals leave the younger part of their adult life span and that age-related changes in sleep slowly develop as individuals enter the older part of their adult life span. Furthermore, while various aspects of sleep architecture are modulated by both the sympathetic and vagal nervous systems during adult life span, the sleep quality is mainly correlated with the sympathetic division after 50 years of age. PMID:26728397

  8. Snow-vegetation interactions across the tundra-taiga interface: stabilising feedbacks or drivers of rapid environmental change?

    NASA Astrophysics Data System (ADS)

    Holden, R.

    2012-04-01

    Mountain Birch, Betula pubescens ssp. czerepanovii, forest in the Abisko area, Swedish Lapland, becomes increasingly patchy towards the tree limit. Where these patches occur mature individuals give way to dwarf shrub tundra in the space of a few meters. Further north, or uphill, of this patchy region the landscape is void of mature trees. Whilst broadly accepted that treeline position is correlated with a particular air temperature, temperature alone cannot explain the observed patchiness of the forest, as it varies little on this scale. Winter snow regime is likely to be an important controlling factor of the position of forest-patch edges. Snow cover protects delicate seedlings from blowing snow and ice particles, as well as providing insulation from freeze-thaw cycles capable of damaging fine roots, however, too great a depth of snow is likely to shorten the growing season to a point where seedlings cannot maintain a positive carbon balance. An insulating layer of snow also ensures that soils stay warmer through the winter months, therefore soil processes continue for longer, resulting in enhanced nutrient availability during the spring, compared to soils experiencing a thin layer of snow cover. Soil moisture, soil disturbance and vegetation cover may also be important controlling factors and these may depend to some extent upon winter snow regimen. Trees are able to trap wind-blown snow by decreasing local wind speed. Presence of trees will result in areas experiencing greater snow cover than a tree-free landscape. Once trees establish they may be able to modify the local environment, in terms of snow depth, creating further areas suitable for forest establishment. This is likely to be particularly true of areas downwind of existing tree patches. Where a sudden change is observed it is likely that a 'switch' is operating, allowing a sudden future change to occur if the system is perturbed. Investigating processes that control the switch between forest and

  9. Study of chaperone-like activity of human haptoglobin: conformational changes under heat shock conditions and localization of interaction sites.

    PubMed

    Ettrich, Rüdiger; Brandt, Wolfgang; Kopecký, Vladimír; Baumruk, Vladimír; Hofbauerová, Katerina; Pavlícek, Zdenek

    2002-10-01

    With respect to the mechanism of chaperone-like activity, we examined the behavior of haptoglobin under heat shock conditions. Secondary structure changes during heat treatment were followed by circular dichroism, Raman and infrared spectroscopy. A model of the haptoglobin tetramer, based on its sequence homology with serine proteases and the CCP modules, has been proposed. Sequence regions responsible for the chaperone-like activity were not fully identical with the region that takes part in formation of the hemoglobin-haptoglobin complex. We can postulate the presence of at least two different chaperone-binding sites on each haptoglobin heavy chain. PMID:12452443

  10. Influence of ozone air pollution on plant-herbivore interactions. Part 1: Biochemical changes in ornamental milkweed (Asclepias curassavica L.; asclepiadaceae) induced by ozone.

    PubMed

    Bolsinger, M; Lier, M E; Lansky, D M; Hughes, P R

    1991-01-01

    A series of fumigation experiments was conducted with bloodflower (Asclepias curassavica L.) in continuous-flow stirred reactors (CSTRs) to elucidate the effects of ozone on foliar concentrations of several primary and secondary plant metabolites relevant to herbivores. Plants 8 weeks of age were subjected to different ozone levels ranging from 0 to 134 nl liter(-1) for exposure periods up to 16 days. Leaves were analyzed for concentration of soluble carbohydrates, starch, free amino acids, soluble protein, total phenolics, and total cardenolides. Significant interactions between the linear effects of ozone concentration and exposure time were found for soluble carbohydrates, amino acids, cardenolides and phenolics. No significant treatment effects could be observed on foliar starch and protein concentration. The metabolic responses of plants to fumigation appeared to be altered by overall plant nutrition. It is possible that the metabolic changes observed in the host plant represent important changes in nutritional quality to insects. PMID:15092115

  11. Aerosol-Cloud Interactions in the South-East Atlantic: Knowledge Gaps, Planned Observations to Address Them, and Implications for Global Climate Change Modeling

    NASA Technical Reports Server (NTRS)

    Redemann, Jens; Wood, R.; Zuidema, P.; Haywood, J.; Luna, B.; Abel, S.

    2015-01-01

    Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles, yet the fate of these particles and their influence on regional and global climate is poorly understood. Particles lofted into the mid-troposphere are transported westward over the South-East (SE) Atlantic, home to one of the three permanent subtropical Stratocumulus (Sc) cloud decks in the world. The stratocumulus "climate radiators" are critical to the regional and global climate system. They interact with dense layers of BB aerosols that initially overlay the cloud deck, but later subside and are mixed into the clouds. These interactions include adjustments to aerosol-induced solar heating and microphysical effects. As emphasized in the latest IPCC report, the global representation of these aerosol-cloud interaction processes in climate models is one of the largest uncertainty in estimates of future climate. Hence, new observations over the SE Atlantic have significant implications for global climate change sc