Homogenization of the soil surface following fire in semiarid grasslands

Treesearch

Carleton S. White

2011-01-01

Semiarid grasslands accumulate soil beneath plant "islands" that are raised above bare interspaces. This fine-scale variation in microtopographic relief is plant-induced and is increased with shrub establishment. Research found that fire-induced water repellency enhanced local-scale soil erosion that reduced variation in microtopographic relief, suggesting...

Genome-wide association study of Arabidopsis thaliana identifies determinants of natural variation in seed oil composition

USDA-ARS?s Scientific Manuscript database

The renewable source of highly reduced carbon provided by plant triacylglycerols fills an ever increasing demand for food, biodiesel and industrial chemicals. Each of these uses requires different compositions of fatty acid proportions in seed oils. Identifying the genes responsible for variation in...

Adaptive variation in offspring size in the terrestrial isopod, Armadillidium vulgare

USGS Publications Warehouse

Brody, M.S.; Lawlor, L.R.

1984-01-01

Variation in the birth size of offspring of the terrestrial isopod, Armadillidium vulgare, was observed in laboratory experiments and in field populations. In the laboratory, larger offspring were produced when the mother's food supply was reduced. In field populations, larger offspring were produced during the summer, a period of reduced food availability. Smaller offspring are produced in the spring, when food is readily available. Females may be making larger young to increase survival during the more severe conditions of the summer breeding period.

Geographic variations in involuntary care and associations with the supply of health and social care: results from a nationwide study.

PubMed

Gandré, Coralie; Gervaix, Jeanne; Thillard, Julien; Macé, Jean-Marc; Roelandt, Jean-Luc; Chevreul, Karine

2018-04-06

Involuntary psychiatric care remains controversial. Geographic disparities in its use can challenge the appropriateness of the care provided when they do not result from different health needs of the population. These disparities should be reduced through dedicated health policies. However, their association with the supply of health and social care, which could be targeted by such policies, has been insufficiently studied. Our objectives were therefore to describe geographic variations in involuntary admission rates across France and to identify the characteristics of the supply of care which were associated with these variations. Involuntary admission rate per 100,000 adult inhabitants was calculated in French psychiatric sectors' catchment areas using 2012 data from the national psychiatric discharge database. Its variations were first described numerically and graphically. Several factors potentially associated with these variations were then considered in a negative binomial regression with an offset term accounting for the size of catchment areas. They included characteristics of the supply of care (public and private care, health and social care, hospital and community-based care, specialised and non-specialised care) as well as adjustment factors related to epidemiological characteristics of the population of each sector's catchment area and its level of urbanization. Such variables were extracted from complementary administrative databases. Supply characteristics associated with geographic variations were identified using a significance level of 0.05. Significant variations in involuntary admission rates were observed between psychiatric sectors' catchment areas with a coefficient of variation close to 80%. These variations were associated with some characteristics of the supply of health and social care in the sectors' catchment areas. Notably, an increase in the availability of community-based private psychiatrists and the capacity of housing institutions for disabled individuals was associated with a decrease in involuntary admission rates while an increase in the availability of general practitioners was associated with an increase in those rates. There is evidence of considerable variations in involuntary admission rates between psychiatric sectors' catchment areas. Our results provide lines of thoughts to reduce such variations, in particular by supporting an increase in the availability of upstream and downstream care in the community.

Future climate stimulates population out-breaks by relaxing constraints on reproduction.

PubMed

Heldt, Katherine A; Connell, Sean D; Anderson, Kathryn; Russell, Bayden D; Munguia, Pablo

2016-09-14

When conditions are stressful, reproduction and population growth are reduced, but when favourable, reproduction and population size can boom. Theory suggests climate change is an increasingly stressful environment, predicting extinctions or decreased abundances. However, if favourable conditions align, such as an increase in resources or release from competition and predation, future climate can fuel population growth. Tests of such population growth models and the mechanisms by which they are enabled are rare. We tested whether intergenerational increases in population size might be facilitated by adjustments in reproductive success to favourable environmental conditions in a large-scale mesocosm experiment. Herbivorous amphipod populations responded to future climate by increasing 20 fold, suggesting that future climate might relax environmental constraints on fecundity. We then assessed whether future climate reduces variation in mating success, boosting population fecundity and size. The proportion of gravid females doubled, and variance in phenotypic variation of male secondary sexual characters (i.e. gnathopods) was significantly reduced. While future climate can enhance individual growth and survival, it may also reduce constraints on mechanisms of reproduction such that enhanced intra-generational productivity and reproductive success transfers to subsequent generations. Where both intra and intergenerational production is enhanced, population sizes might boom.

The effect of gravitational and pressure torques on Titan's length-of-day variations

NASA Astrophysics Data System (ADS)

Van Hoolst, T.; Rambaux, N.; Karatekin, Ö.; Baland, R.-M.

2009-03-01

Cassini radar observations show that Titan's spin is slightly faster than synchronous spin. Angular momentum exchange between Titan's surface and the atmosphere over seasonal time scales corresponding to Saturn's orbital period of 29.5 year is the most likely cause of the observed non-synchronous rotation. We study the effect of Saturn's gravitational torque and torques between internal layers on the length-of-day (LOD) variations driven by the atmosphere. Because static tides deform Titan into an ellipsoid with the long axis approximately in the direction to Saturn, non-zero gravitational and pressure torques exist that can change the rotation rate of Titan. For the torque calculation, we estimate the flattening of Titan and its interior layers under the assumption of hydrostatic equilibrium. The gravitational forcing by Saturn, due to misalignment of the long axis of Titan with the line joining the mass centers of Titan and Saturn, reduces the LOD variations with respect to those for a spherical Titan by an order of magnitude. Internal gravitational and pressure coupling between the ice shell and the interior beneath a putative ocean tends to reduce any differential rotation between shell and interior and reduces further the LOD variations by a few times. For the current estimate of the atmospheric torque, we obtain LOD variations of a hydrostatic Titan that are more than 100 times smaller than the observations indicate when Titan has no ocean as well as when a subsurface ocean exists. Moreover, Saturn's torque causes the rotation to be slower than synchronous in contrast to the Cassini observations. The calculated LOD variations could be increased if the atmospheric torque is larger than predicted and or if fast viscous relaxation of the ice shell could reduce the gravitational coupling, but it remains to be studied if a two order of magnitude increase is possible and if these effects can explain the phase difference of the predicted rotation variations. Alternatively, the large differences with the observations may suggest that non-hydrostatic effects in Titan are important. In particular, we show that the amplitude and phase of the calculated rotation variations are similar to the observed values if non-hydrostatic effects could strongly reduce the equatorial flattening of the ice shell above an internal ocean.

The Influence of Internal and External Torques on Titan's Length-of-day Variations

NASA Astrophysics Data System (ADS)

van Hoolst, T.; Karatekin, O.; Rambaux, N.

2008-12-01

Cassini radar observations show that Titan's spin is slightly faster than synchronous spin. Angular momentum exchange between Titan and its atmosphere is the most likely cause of the observed non-synchronous rotation. We study the effect of Saturn's gravitational torque and torques between Titan's internal layers on the length-of-day (LOD) variations driven by the atmosphere. Those torques depend on the equatorial flattening of Titan resulting from static tides raised by Saturn. We calculate Titan's flattening under the assumption of hydrostatic equilibrium and show that the gravitational forcing by Saturn, due to misalignment of the long axis of Titan with the line joining the mass centers of Titan and Saturn, reduces the LOD variations with respect to those for a spherical Titan by an order of magnitude. Internal gravitational and pressure coupling between the ice shell and the interior beneath a putative ocean tends to diminish any differential rotation between shell and interior and reduces further the LOD variations by a few times. For the current estimate of the atmospheric torque, we obtain LOD variations of a hydrostatic Titan that are more than 50 times smaller than the observations indicate when a subsurface ocean exists and more than 100 times smaller when Titan has no ocean. Moreover, Saturn's torque causes the rotation to be slower than synchronous in contrast to the Cassini observations. Those large differences with the observations suggest that non-hydrostatic effects in Titan are important. In particular, we show that the amplitude and phase of the calculated rotation variations would be similar to the observed values if non-hydrostatic effects strongly reduce the equatorial flattening of the ice shell above an internal ocean. Alternatively, the calculated LOD variations could be increased if the atmospheric torque is larger than predicted or if fast viscous relaxation of the ice shell could reduce the gravitational coupling, but it remains to be studied if a two order of magnitude increase is possible and if these effects can explain the phase difference of the predicted rotation variations.

Inherent variations in CO-H2S-mediated carotid body O2 sensing mediate hypertension and pulmonary edema

PubMed Central

Peng, Ying-Jie; Makarenko, Vladislav V.; Nanduri, Jayasri; Vasavda, Chirag; Raghuraman, Gayatri; Yuan, Guoxiang; Gadalla, Moataz M.; Kumar, Ganesh K.; Snyder, Solomon H.; Prabhakar, Nanduri R.

2014-01-01

Oxygen (O2) sensing by the carotid body and its chemosensory reflex is critical for homeostatic regulation of breathing and blood pressure. Humans and animals exhibit substantial interindividual variation in this chemosensory reflex response, with profound effects on cardiorespiratory functions. However, the underlying mechanisms are not known. Here, we report that inherent variations in carotid body O2 sensing by carbon monoxide (CO)-sensitive hydrogen sulfide (H2S) signaling contribute to reflex variation in three genetically distinct rat strains. Compared with Sprague-Dawley (SD) rats, Brown-Norway (BN) rats exhibit impaired carotid body O2 sensing and develop pulmonary edema as a consequence of poor ventilatory adaptation to hypobaric hypoxia. Spontaneous Hypertensive (SH) rat carotid bodies display inherent hypersensitivity to hypoxia and develop hypertension. BN rat carotid bodies have naturally higher CO and lower H2S levels than SD rat, whereas SH carotid bodies have reduced CO and greater H2S generation. Higher CO levels in BN rats were associated with higher substrate affinity of the enzyme heme oxygenase 2, whereas SH rats present lower substrate affinity and, thus, reduced CO generation. Reducing CO levels in BN rat carotid bodies increased H2S generation, restoring O2 sensing and preventing hypoxia-induced pulmonary edema. Increasing CO levels in SH carotid bodies reduced H2S generation, preventing hypersensitivity to hypoxia and controlling hypertension in SH rats. PMID:24395806

Process Improvement of Reactive Dye Synthesis Using Six Sigma Concept

NASA Astrophysics Data System (ADS)

Suwanich, Thanapat; Chutima, Parames

2017-06-01

This research focuses on the problem occurred in the reactive dye synthesis process of a global manufacturer in Thailand which producing various chemicals for reactive dye products to supply global industries such as chemicals, textiles and garments. The product named “Reactive Blue Base” is selected in this study because it has highest demand and the current chemical yield shows a high variation, i.e. yield variation of 90.4% - 99.1% (S.D. = 2.405 and Cpk = -0.08) and average yield is 94.5% (lower than the 95% standard set by the company). The Six Sigma concept is applied aiming at increasing yield and reducing variation of this process. This approach is suitable since it provides a systematic guideline with five improvement phases (DMAIC) to effectively tackle the problem and find the appropriate parameter settings of the process. Under the new parameter settings, the process yield variation is reduced to range between 96.5% - 98.5% (S.D. = 0.525 and Cpk = 1.83) and the average yield is increased to 97.5% (higher than the 95% standard set by the company).

Tropical Warm Pool Surface Heat Budgets and Temperature: Contrasts Between 1997-98 El Nino and 1998-99 La Nina

NASA Technical Reports Server (NTRS)

Chou, Shu-Hsien; Chou, Ming-Dah; Chan, Pui-King; Lin, Po-Hsiung; Wang, Kung-Hwa

2003-01-01

Seasonal and interannual variations of the net surface heating F(sub NET) and sea surface temperature tendency (T(sub s)/dt) in the tropical eastern Indian and western Pacific Oceans are studied. The surface heat fluxes are derived from the Special Sensor Microwave/Imager and Japanese Geostationary Meteorological Satellite radiance measurements for the period October 1997-September 2000. It is found that the magnitude of solar heating is lager than that of evaporative cooling, but the spatial variation of the latter is significantly large than the former. As a result, the spatial variations of seasonal and interannual variability of F(sub NET), follow closely that of evaporative cooling. Seasonal variations of F(sub NET) and T(sub s)/dt are significantly correlated, except for the equatorial western Pacific. The high correlation is primarily attributable to high correlation between seasonal cycles of solar heating and T(sub s)/dt. The change of F(sub NET) between 1997-98 El Nino and 1998-99 La Nina is significantly larger in the tropical eastern Indian Ocean than tropical western Pacific. For the former region, the reduced evaporative cooling arising from weakened winds during the El Nino is generally associated with enhanced solar heating due to decreased cloudiness, and thus increases the interannual variability of F(sub NET). For the latter region, the reduced evaporative cooling due to weakened winds is generally associated with but exceeds the reduced solar heating arising from increased cloudiness, and vise versa. Thus the interannual variability of F(sub NET) is reduced due to this offsetting effect. Interannual variations of F(sub NET) and T(sub s)/dt have very low correlation. This is most likely related to interannual variability of ocean dynamics, which includes the variations of solar radiation penetrating through oceanic mixed layer, upwelling of cold thermocline water, Indonesian throughflow for transporting heat from the Pacific to Indian Ocean, and interhemispheric transport in the Indian Ocean.

Does a strategy to promote shared decision-making reduce medical practice variation in the choice of either single or double embryo transfer after in vitro fertilisation? A secondary analysis of a randomised controlled trial.

PubMed

Brabers, Anne E M; van Dijk, Liset; Groenewegen, Peter P; van Peperstraten, Arno M; de Jong, Judith D

2016-05-06

The hypothesis that shared decision-making (SDM) reduces medical practice variations is increasingly common, but no evidence is available. We aimed to elaborate further on this, and to perform a first exploratory analysis to examine this hypothesis. This analysis, based on a limited data set, examined how SDM is associated with variation in the choice of single embryo transfer (SET) or double embryo transfer (DET) after in vitro fertilisation (IVF). We examined variation between and within hospitals. A secondary analysis of a randomised controlled trial. 5 hospitals in the Netherlands. 222 couples (woman aged <40 years) on a waiting list for a first IVF cycle, who could choose between SET and DET (ie, ≥2 embryos available). SDM via a multifaceted strategy aimed to empower couples in deciding how many embryos should be transferred. The strategy consisted of decision aid, support of IVF nurse and the offer of reimbursement for an extra treatment cycle. Control group received standard IVF care. Difference in variation due to SDM in the choice of SET or DET, both between and within hospitals. There was large variation in the choice of SET or DET between hospitals in the control group. Lower variation between hospitals was observed in the group with SDM. Within most hospitals, variation in the choice of SET or DET appeared to increase due to SDM. Variation particularly increased in hospitals where mainly DET was chosen in the control group. Although based on a limited data set, our study gives a first insight that including patients' preferences through SDM results in less variation between hospitals, and indicates another pattern of variation within hospitals. Variation that results from patient preferences could be potentially named the informed patient rate. Our results provide the starting point for further research. NCT00315029; Post-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

The reduction in circulating levels of melatonin may be associated with the development of preeclampsia.

PubMed

Zeng, K; Gao, Y; Wan, J; Tong, M; Lee, A C; Zhao, M; Chen, Q

2016-11-01

Placental dysfunction and oxidative stress contribute to the pathogenesis of preeclampsia, which is a pregnancy-specific disorder. It has been suggested that the incidence of preeclampsia has a seasonal variation. Melatonin, as a seasonal factor, has been suggested to be involved in a successful pregnancy. In this study, we investigated the association of circulating levels of melatonin with preeclampsia. Serum was collected from women with preeclampsia (n=113) and gestation-matched healthy pregnant women, and the levels of melatonin were measured. In addition, the expression of melatonin receptors was examined in preeclamptic placentae (n=27). The association of the incidence of preeclampsia and seasonal variation was also analysed from 1491 women with preeclampsia within 77 745 healthy pregnancies. The serum levels of melatonin were significantly reduced in women with preeclampsia at presentation and these reduced serum levels of melatonin were not associated with the severity or time onset of preeclampsia nor with seasonal variation. The expression of melatonin receptor, MT1 was reduced in preeclamptic placentae. The incidence of preeclampsia was did exhibit seasonal variation, but this was largely due to the increase in the incidence of mild or late-onset preeclampsia. Our results demonstrate that reduced melatonin levels are associated with the development of preeclampsia but that the circulating levels of melatonin do not appear to be subject to seasonal variation during pregnancy.

EqualChance: Addressing Intra-set Write Variation to Increase Lifetime of Non-volatile Caches

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

Mittal, Sparsh; Vetter, Jeffrey S

To address the limitations of SRAM such as high-leakage and low-density, researchers have explored use of non-volatile memory (NVM) devices, such as ReRAM (resistive RAM) and STT-RAM (spin transfer torque RAM) for designing on-chip caches. A crucial limitation of NVMs, however, is that their write endurance is low and the large intra-set write variation introduced by existing cache management policies may further exacerbate this problem, thereby reducing the cache lifetime significantly. We present EqualChance, a technique to increase cache lifetime by reducing intra-set write variation. EqualChance works by periodically changing the physical cache-block location of a write-intensive data item withinmore » a set to achieve wear-leveling. Simulations using workloads from SPEC CPU2006 suite and HPC (high-performance computing) field show that EqualChance improves the cache lifetime by 4.29X. Also, its implementation overhead is small, and it incurs very small performance and energy loss.« less

Cesarean Delivery Rates Vary 10-Fold Among US Hospitals; Reducing Variation May Address Quality, Cost Issues

PubMed Central

Kozhimannil, Katy Backes; Law, Michael R.; Virnig, Beth A.

2013-01-01

Cesarean delivery is the most commonly performed surgical procedure in the United States, and cesarean rates are increasing. Working with 2009 data from 593 US hospitals nationwide, we found that cesarean rates varied tenfold across hospitals, from 7.1 percent to 69.9 percent. Even for women with lower-risk pregnancies, in which more limited variation might be expected, cesarean rates varied fifteen-fold, from 2.4 percent to 36.5 percent. Thus, vast differences in practice patterns are likely to be driving the costly overuse of cesarean delivery in many US hospitals. Because Medicaid pays for nearly half of US births, government efforts to decrease variation are warranted. We focus on four promising directions for reducing these variations, including better coordination of maternity care, more data collection and measurement, tying Medicaid payment to quality improvement, and enhancing patient-centered decision making through public reporting. PMID:23459732

Evidence of reduced recombination rate in human regulatory domains.

PubMed

Liu, Yaping; Sarkar, Abhishek; Kheradpour, Pouya; Ernst, Jason; Kellis, Manolis

2017-10-20

Recombination rate is non-uniformly distributed across the human genome. The variation of recombination rate at both fine and large scales cannot be fully explained by DNA sequences alone. Epigenetic factors, particularly DNA methylation, have recently been proposed to influence the variation in recombination rate. We study the relationship between recombination rate and gene regulatory domains, defined by a gene and its linked control elements. We define these links using expression quantitative trait loci (eQTLs), methylation quantitative trait loci (meQTLs), chromatin conformation from publicly available datasets (Hi-C and ChIA-PET), and correlated activity links that we infer across cell types. Each link type shows a "recombination rate valley" of significantly reduced recombination rate compared to matched control regions. This recombination rate valley is most pronounced for gene regulatory domains of early embryonic development genes, housekeeping genes, and constitutive regulatory elements, which are known to show increased evolutionary constraint across species. Recombination rate valleys show increased DNA methylation, reduced doublestranded break initiation, and increased repair efficiency, specifically in the lineage leading to the germ line. Moreover, by using only the overlap of functional links and DNA methylation in germ cells, we are able to predict the recombination rate with high accuracy. Our results suggest the existence of a recombination rate valley at regulatory domains and provide a potential molecular mechanism to interpret the interplay between genetic and epigenetic variations.

Impact of Spodoptera frugiperda neonate pretreatment conditions on Vip3Aa19 insecticidal protein activity and laboratory bioassay variation.

PubMed

Da Silva, Karen F; Spencer, Terence A; Camargo Gil, Carolina; Siegfried, Blair D; Walters, Frederick S

2016-04-01

Variation in response to insecticidal proteins is common upon repetition of insect bioassays. Understanding this variation is a prerequisite to detecting biologically important differences. We tracked neonate Spodoptera frugiperda (J.E. Smith) susceptibility to Vip3Aa19 over 17 generations using standardized bioassay methods. Five larval pretreatment conditions and one bioassay condition were tested to determine whether susceptibility was affected. These included: storage time; prefeeding; storage at reduced temperature; storage at reduced humidity; colony introgression of field-collected individuals. Extremes of photoperiod during the bioassay itself were also examined. LC50 values for two strains of S. frugiperda varied 6.6-fold or 8.8-fold over 17 generations. Storage time and humidity had no impact on Vip3Aa19 susceptibility, whereas prefeeding significantly reduced subsequent mortality (by 27%). Storage at reduced temperature increased mortality for one colony (from 45.6 to 73.0%) but not for the other. Introgression of field-collected individuals affected susceptibility at the first generation but not for subsequent generations. A 24 h bioassay photophase significantly reduced susceptibility (by 26%) for both colonies. Certain pretreatment and bioassay conditions were identified that can affect S. frugiperda Vip3Aa19 susceptibility, but innate larval heterogeneity was also present. Our observations should help to increase the consistency of insecticidal protein bioassay results. © 2015 Syngenta Crop Protection, LLC. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Variation of NEE and its affecting factors in a vineyard of arid region of northwest China

NASA Astrophysics Data System (ADS)

Guo, W. H.; Kang, S. Z.; Li, F. S.; Li, S. E.

2014-02-01

To understand the variation of net ecosystem CO2 exchange (NEE) in orchard ecosystem and it's affecting factors, carbon flux was measured using eddy covariance system in a wine vineyard in arid northwest China during 2008-2010. Results show that vineyard NEE was positive value at the early growth stage, higher negative value at the mid-growth stage, and lower negative value at the later growth stage. Diurnal variation of NEE was "W" shaped curve in sunny day, but "U" shaped curve in cloudy day. Irrigation and pruning did not affect diurnal variation shape of NEE, however, irrigation reduced the difference between maximal and minimal value of NEE and pruning reduced the carbon sink capacity. The main factors affecting hourly NEE were canopy conductance (gc) and net radiation (Rn). The hourly NEE increased with the increase of gc or Rn when gc was less than 0.02 m·s-1 or Rn was between 0 and 200 W·m-2. The main factors affecting both daily and seasonal NEE were gc, air temperature (Ta), atmospheric CO2 density, vapour pressure deficit (VPD) and soil moisture content.

Evaluation of ways and procedures to reduce construction cost and increase competition.

DOT National Transportation Integrated Search

2009-01-01

Construction cost inflation is affecting many state highway agencies including the Texas Department of : Transportation While some of this increase can be attributed to factors such as soaring cost of energy, : reports of large variations in cost of ...

Changes in hemoglobin-oxygen affinity with shape variations of red blood cells

NASA Astrophysics Data System (ADS)

Chowdhury, Aniket; Dasgupta, Raktim; Majumder, Shovan K.

2017-10-01

Shape variations of red blood cells (RBCs) are known to occur upon exposure to various drugs or under diseased conditions. The commonly observed discocytic RBCs can be transformed to echinocytic or stomatocytic shape under such conditions. Raman spectra of the three major shape variations, namely discocyte, echinocyte, and stomatocyte, of RBCs were studied while subjecting the cells to oxygenated and deoxygenated conditions. Analysis of the recorded spectra suggests an increased level of hemoglobin (Hb)-oxygen affinity for the echinocytes. Also, some level of Hb degradation could be noticed for the deoxygenated echinocytes. The effects may arise from a reduced level of intracellular adenosine triphosphate in echinocytic cells and an increased fraction of submembrane Hb.

Random Signal Fluctuations Can Reduce Random Fluctuations in Regulated Components of Chemical Regulatory Networks

NASA Astrophysics Data System (ADS)

Paulsson, Johan; Ehrenberg, Måns

2000-06-01

Many intracellular components are present in low copy numbers per cell and subject to feedback control. We use chemical master equations to analyze a negative feedback system where species X and S regulate each other's synthesis with standard intracellular kinetics. For a given number of X-molecules, S-variation can be significant. We show that this signal noise does not necessarily increase X-variation as previously thought but, surprisingly, can be necessary to reduce it below a Poissonian limit. The principle resembles Stochastic Resonance in that signal noise improves signal detection.

Egg size variation among tropical and temperate songbirds: An embryonic temperature hypothesis

PubMed Central

Martin, Thomas E.

2008-01-01

Species with “slow” life history strategies (long life, low fecundity) are thought to produce high-quality offspring by investing in larger, but fewer, young. Larger eggs are indeed associated with fewer eggs across taxa and can yield higher-quality offspring. Tropical passerines appear to follow theory because they commonly exhibit slow life history strategies and produce larger, but fewer, eggs compared with northern species. Yet, I show here that relative egg mass (corrected for adult mass) varies extensively in the tropics and subtropics for the same clutch size, and this variation is unexplained. I propose a hypothesis to explain egg size variation both within the tropics and between latitudes: Relative egg mass increases in species with cooler egg temperatures and longer embryonic periods to offset associated increases in energetic requirements of embryos. Egg temperatures of birds are determined by parental incubation behavior and are often cooler among tropical passerines because of reduced parental attentiveness of eggs. Here, I show that cooler egg temperatures and longer embryonic periods explained the enigmatic variation in egg mass within and among regions, based on field studies in tropical Venezuela (36 species), subtropical Argentina (16 species), and north temperate Arizona (20 species). Alternative explanations are not supported. Thus, large egg sizes may reflect compensation for increased energetic requirements of cool egg temperatures and long embryonic periods that result from reduced parental attentiveness in tropical birds. PMID:18591674

Study of landscape patterns of variation and optimization based on non-point source pollution control in an estuary.

PubMed

Jiang, Mengzhen; Chen, Haiying; Chen, Qinghui; Wu, Haiyan

2014-10-15

Appropriate increases in the "sink" of a landscape can reduce the risk of non-point source pollution (NPSP) to the sea at relatively lower costs and at a higher efficiency. Based on high-resolution remote sensing image data taken between 2003 and 2008, we analyzed the "source" and "sink" landscape pattern variations of nitrogen and phosphorus pollutants in the Jiulongjiang estuary region. The contribution to the sea and distribution of each pollutant in the region was calculated using the LCI and mGLCI models. The results indicated that an increased amount of pollutants was contributed to the sea, and the "source" area of the nitrogen NPSP in the study area increased by 32.75 km(2). We also propose a landscape pattern optimization to reduce pollution in the Jiulongjiang estuary in 2008 through the conversion of cultivated land with slopes greater than 15° and paddy fields near rivers, and an increase in mangrove areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of digital terrain data to quantify and reduce the topographic effect on LANDSAT data

NASA Technical Reports Server (NTRS)

Justice, C. O.; Wharton, S. W.; Holben, B. N. (Principal Investigator)

1980-01-01

Integration of LANDSAT multispectral scanner (MSS) data with 30 m U.S. Geological Survey (USGS) digital terrain data was undertaken to quantify and reduce the topographic effect on imagery of a forested mountain ridge test site in central Pennsylvania. High Sun angle imagery revealed variation of as much as 21 pixel values in data for slopes of different angles and aspects with uniform surface cover. Large topographic effects were apparent in MSS 4 and 5 was due to a combination of high absorption by the forest cover and the MSS quantization. Four methods for reducing the topographic effect were compared. Band ratioing of MSS 6/5 and MSS 7/5 did not eliminate the topographic effect because of the lack of variation in MSS 4 and 5 radiances. The three radiance models examined to reduce the topographic effect required integration of the digital terrain data. Two Lambertian models increased the variation in the LANDSAT radiances. The nonLambertian model considerably reduced (86 per cent) the topographic effect in the LANDSAT data. The study demonstrates that high quality digital terrain data, as provided by the USGS digital elevation model data, can be used to enhance the utility of multispectral satellite data.

New alleles of FATB-1A to reduce palmitic acid levels in soybean

USDA-ARS?s Scientific Manuscript database

In wild-type soybeans, palmitic acid typically constitutes 10% of the total seed oil. Palmitic acid is a saturated fat linked to increased cholesterol levels, and reducing levels of saturated fats in soybean oil has been a breeding target. To identify novel and useful variation that could help in re...

The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures

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

Puthen-Veettil, B., E-mail: b.puthen-veettil@unsw.edu.au; Patterson, R.; König, D.

Efficient iso-entropic energy filtering of electronic waves can be realized through nanostructures with three dimensional confinement, such as quantum dot resonant tunneling structures. Large-area deployment of such structures is useful for energy selective contacts but such configuration is susceptible to structural disorders. In this work, the transport properties of quantum-dot-based wide-area resonant tunneling structures, subject to realistic disorder mechanisms, are studied. Positional variations of the quantum dots are shown to reduce the resonant transmission peaks while size variations in the device are shown to reduce as well as broaden the peaks. Increased quantum dot size distribution also results in amore » peak shift to lower energy which is attributed to large dots dominating transmission. A decrease in barrier thickness reduces the relative peak height while the overall transmission increases dramatically due to lower “series resistance.” While any shift away from ideality can be intuitively expected to reduce the resonance peak, quantification allows better understanding of the tolerances required for fabricating structures based on resonant tunneling phenomena/.« less

Investigation of distributor vane jets to decrease the unsteady load on hydro turbine runner blades

NASA Astrophysics Data System (ADS)

Lewis, B. J.; Cimbala, J. M.; Wouden, A. M.

2012-11-01

As the runner blades of a Francis hydroturbine pass though the wakes created from the wicket gates, they experience a significant change in absolute velocity, flow angle, and pressure. The concept of adding jets to the trailing edge of the wicket gates is proposed as a method for reducing the dynamic load on the hydroturbine runner blades. Computational experiments show a decrease in velocity variation experienced by the runner blade with the addition of the jets. The decrease in velocity variation resulted in a 43% decrease in global torque variation at the runner passing frequency. However, an increased variation was observed at the wicket gate passing frequency. Also, a 5.7% increase in average global torque was observed with the addition of blowing from the trailing-edge of the wicket gates.

Economic Hardship and Educational Differentials in Disability in 26 European Countries.

PubMed

Cambois, Emmanuelle; Solé-Auró, Aïda; Robine, Jean-Marie

2016-10-01

The objective of this article is to study to what extent European variations in differentials in disability by education level are associated to variation in poverty. Using the European Statistics on Income and Living Conditions (EU-SILC) for 26 countries, we measure the prevalence of activity limitation (AL) and the rate of economic hardship (EH) by level of education. We measure the increased AL prevalence (disadvantage) of the low-educated relative to the middle-educated and the reduced AL prevalence (advantage) of the high-educated groups, controlling or not for EH. The rate of EH and the extent of the AL-advantage/disadvantage vary substantially across Europe. EH contributes to the AL-advantage/disadvantage but to different extent depending on its level across educational groups. Associations between poverty, education, and disability are complex. In general, large EH goes along with increased disability differentials. Actions to reduce poverty are needed in Europe to reduce the levels and differentials in disability. © The Author(s) 2016.

Analysis of holding time variations to Ni and Fe content and morphology in nickel laterite limonitic reduction process by using coal-dolomite bed

NASA Astrophysics Data System (ADS)

Abdul, Fakhreza; Pintowantoro, Sungging; Yuwandono, Ridwan Bagus

2018-04-01

With the depletion of nickel sulfide ore resources, the nickel laterit processing become an attention to fulfill nickel world demans. Reducing laterite nickel by using a low cost carbonaceous reductan has proved produces high grade ferronickel alloy. In this research, reduction was carried out to low grade laterite nickel (limonite) with 1.25% nikel content by using CO gas reductant formed by reaction between coal and dolomite. Reduction process preceded by forming brickets mixture from limonit ore, coal, and Na2SO4, then the brickets placed inside crucible bed together with dolomit and reduced at temperature 1400 °C with holding time variations 4, 6, and 8 hours. EDX, XRD, and SEM test were carried out to find out the Ni and nickel grade after reduced, the phases that formed, and the morphology brickets after reduced. The reduction results shows that the highest increase on nickel grade was obtained by 8 hours holding time increasing 5.84 % from initial grade, and the highest recovery was obtained by 6 hours holding time with recovery 88.51 %. While the higest increase on Fe grade was obtained by 4 hours holding time, and the highest recovery Fe was obtained by 4 hours holding time with recovery 85.41%.

Enhanced precipitation variability decreases grass- and increases shrub-productivity

PubMed Central

Gherardi, Laureano A.; Sala, Osvaldo E.

2015-01-01

Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plant-functional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society. PMID:26417095

Within and between Population Variation in Epidermal Club Cell Investment in a Freshwater Prey Fish: A Cautionary Tale for Evolutionary Ecologists

PubMed Central

Manek, Aditya K.; Ferrari, Maud C. O.; Pollock, Robyn J.; Vicente, Daniel; Weber, Lynn P.; Chivers, Douglas P.

2013-01-01

Many prey fishes possess large club cells in their epidermis. The role of these cells has garnered considerable attention from evolutionary ecologists. These cells likely form part of the innate immune system of fishes, however, they also have an alarm function, releasing chemical cues that serve to warn nearby conspecifics of danger. Experiments aimed at understanding the selection pressures leading to the evolution of these cells have been hampered by a surprisingly large intraspecific variation in epidermal club cell (ECC) investment. The goal of our current work was to explore the magnitude and nature of this variation in ECC investment. In a field survey, we documented large differences in ECC investment both within and between several populations of minnows. We then tested whether we could experimentally reduce variation in mean ECC number by raising fish under standard laboratory conditions for 4 weeks. Fish from different populations responded very differently to being held under standard laboratory conditions; some populations showed an increase in ECC investment while others remained unchanged. More importantly, we found some evidence that we could reduce within population variation in ECC investment through time, but could not reduce among-population variation in mean ECC investment. Given the large variation we observed in wild fish and our limited ability to converge mean cell number by holding the fish under standard conditions, we caution that future studies may be hard pressed to find subtle effects of various experimental manipulations; this will make elucidating the selection pressures leading to the evolution of the cells challenging. PMID:23469175

Habitat degradation and fishing effects on the size structure of coral reef fish communities.

PubMed

Wilson, S K; Fisher, R; Pratchett, M S; Graham, N A J; Dulvy, N K; Turner, R A; Cakacaka, A; Polunin, N V C

2010-03-01

Overfishing and habitat degradation through climate change pose the greatest threats to sustainability of marine resources on coral reefs. We examined how changes in fishing pressure and benthic habitat composition influenced the size spectra of island-scale reef fish communities in Lau, Fiji. Between 2000 and 2006 fishing pressure declined in the Lau Islands due to declining human populations and reduced demand for fresh fish. At the same time, coral cover declined and fine-scale architectural complexity eroded due to coral bleaching and outbreaks of crown-of-thorns starfish, Acanthaster planci. We examined the size distribution of reef fish communities using size spectra analysis, the linearized relationship between abundance and body size class. Spatial variation in fishing pressure accounted for 31% of the variation in the slope of the size spectra in 2000, higher fishing pressure being associated with a steeper slope, which is indicative of fewer large-bodied fish and/or more small-bodied fish. Conversely, in 2006 spatial variation in habitat explained 53% of the variation in the size spectra slopes, and the relationship with fishing pressure was much weaker (approximately 12% of variation) than in 2000. Reduced cover of corals and lower structural complexity was associated with less steep size spectra slopes, primarily due to reduced abundance of fish < 20 cm. Habitat degradation will compound effects of fishing on coral reefs as increased fishing reduces large-bodied target species, while habitat loss results in fewer small-bodied juveniles and prey that replenish stocks and provide dietary resources for predatory target species. Effective management of reef resources therefore depends on both reducing fishing pressure and maintaining processes that encourage rapid recovery of coral habitat.

The phase differences of the interdecadal variabilities of tropical cyclone activity in the peak and late seasons over the western North Pacific

NASA Astrophysics Data System (ADS)

Fan, Tingting; Xu, Shibin; Huang, Fei; Zhao, Jinping

2018-04-01

This study compares the interdecadal variations in tropical cyclone (TC) activities over the western North Pacific (WNP) basin during the peak season (July-September) and late season (October-December) of 1955-2014 and explores the possible physical mechanisms behind the variations. Both the peak- and late-season tropical storm (TS) days show distinct interdecadal variations, while the late-season TS days lead the peak-season TS days by approximately 4 years on an interdecadal time scale. The late-season TC activity is related to the east-west sea surface temperature (SST) gradient across the equatorial Pacific. The westerly winds induced by the SST gradient can reduce the vertical wind shear and increase the low-level vorticity, which favors TC genesis over the TC genesis region. The peak-season TC activity appears to relate to the SST gradient between the Indian Ocean and the Central Pacific. The westerly wind induced by the SST gradient can reduce the vertical wind shear and increase the mid-level relative humidity, thereby enhancing the TC activity. The full picture of the interdecadal variation in the WNP TC activity during the peak and late seasons revealed in this study provides a new perspective on the seasonal TC forecasts and future projections.

The biomechanical effects of variation in the maximum forces exerted by trunk muscles on the joint forces and moments in the lumbar spine: a finite element analysis.

PubMed

Kim, K; Lee, S K; Kim, Y H

2010-10-01

The weakening of trunk muscles is known to be related to a reduction of the stabilization function provided by the muscles to the lumbar spine; therefore, strengthening deep muscles might reduce the possibility of injury and pain in the lumbar spine. In this study, the effect of variation in maximum forces of trunk muscles on the joint forces and moments in the lumbar spine was investigated. Accordingly, a three-dimensional finite element model of the lumbar spine that included the trunk muscles was used in this study. The variation in maximum forces of specific muscle groups was then modelled, and joint compressive and shear forces, as well as resultant joint moments, which were presumed to be related to spinal stabilization from a mechanical viewpoint, were analysed. The increase in resultant joint moments occurred owing to decrease in maximum forces of the multifidus, interspinales, intertransversarii, rotatores, iliocostalis, longissimus, psoas, and quadratus lumborum. In addition, joint shear forces and resultant joint moments were reduced as the maximum forces of deep muscles were increased. These results from finite element analysis indicate that the variation in maximum forces exerted by trunk muscles could affect the joint forces and joint moments in the lumbar spine.

Statistical variability study of random dopant fluctuation on gate-all-around inversion-mode silicon nanowire field-effect transistors

NASA Astrophysics Data System (ADS)

Yoon, Jun-Sik; Rim, Taiuk; Kim, Jungsik; Kim, Kihyun; Baek, Chang-Ki; Jeong, Yoon-Ha

2015-03-01

Random dopant fluctuation effects of gate-all-around inversion-mode silicon nanowire field-effect transistors (FETs) with different diameters and extension lengths are investigated. The nanowire FETs with smaller diameter and longer extension length reduce average values and variations of subthreshold swing and drain-induced barrier lowering, thus improving short channel immunity. Relative variations of the drain currents increase as the diameter decreases because of decreased current drivability from narrower channel cross-sections. Absolute variations of the drain currents decrease critically as the extension length increases due to decreasing the number of arsenic dopants penetrating into the channel region. To understand variability origins of the drain currents, variations of source/drain series resistance and low-field mobility are investigated. All these two parameters affect the variations of the drain currents concurrently. The nanowire FETs having extension lengths sufficient to prevent dopant penetration into the channel regions and maintaining relatively large cross-sections are suggested to achieve suitable short channel immunity and small variations of the drain currents.

Egg size variation among tropical and temperate songbirds: An embryonic temperature hypothesis

USGS Publications Warehouse

Martin, T.E.

2008-01-01

Species with 'slow' life history strategies (long life, low fecundity) are thought to produce high-quality offspring by investing in larger, but fewer, young. Larger eggs are indeed associated with fewer eggs across taxa and can yield higher-quality offspring. Tropical passerines appear to follow theory because they commonly exhibit slow life history strategies and produce larger, but fewer, eggs compared with northern species. Yet, I show here that relative egg mass (corrected for adult mass) varies extensively in the tropics and subtropics for the same clutch size, and this variation is unexplained. I propose a hypothesis to explain egg size variation both within the tropics and between latitudes: Relative egg mass increases in species with cooler egg temperatures and longer embryonic periods to offset associated increases in energetic requirements of embryos. Egg temperatures of birds are determined by parental incubation behavior and are often cooler among tropical passerines because of reduced parental attentiveness of eggs. Here, I show that cooler egg temperatures and longer embryonic periods explained the enigmatic variation in egg mass within and among regions, based on field studies in tropical Venezuela (36 species), subtropical Argentina (16 species), and north temperate Arizona (20 species). Alternative explanations are not supported. Thus, large egg sizes may reflect compensation for increased energetic requirements of cool egg temperatures and long embryonic periods that result from reduced parental attentiveness in tropical birds. ?? 2008 by The National Academy of Sciences of the USA.

Implications for Welfare, Productivity and Sustainability of the Variation in Reported Levels of Mortality for Laying Hen Flocks Kept in Different Housing Systems: A Meta-Analysis of Ten Studies

PubMed Central

Weeks, Claire A.; Lambton, Sarah L.; Williams, Adrian G.

2016-01-01

Data from ten sources comprising 3,851 flocks were modelled to identify variation in levels of mortality in laying hens. The predicted increase with age was curvilinear with significant variation between the seven breed categories. Mortality was higher in loose housing systems than in cages and variable within system, confirming previous reports. Cumulative mortality (CM) was higher in flocks with intact beaks (χ2 = 6.03; df 1; p = 0.014) than in those with trimmed beaks. Most data were available for free-range systems (2,823 flocks), where producer recorded CM at 60–80 weeks of age averaged 10% but with a range from 0% to 69.3%. Life cycle assessment showed that the main effect of increased levels of hen mortality is to increase the relative contribution of breeding overheads, so increasing environmental burdens per unit of production. Reducing CM to levels currently achieved by the 1st quartile could reduce flock greenhouse gas emissions by as much as 25%. Concurrently this would enhance hen welfare and better meet the expectation of egg consumers. More research to understand the genetic x environment interaction and detailed records of the causes of mortality is required so that improved genotypes can be developed for different systems and different breeds can be better managed within systems. PMID:26734933

Implications for Welfare, Productivity and Sustainability of the Variation in Reported Levels of Mortality for Laying Hen Flocks Kept in Different Housing Systems: A Meta-Analysis of Ten Studies.

PubMed

Weeks, Claire A; Lambton, Sarah L; Williams, Adrian G

2016-01-01

Data from ten sources comprising 3,851 flocks were modelled to identify variation in levels of mortality in laying hens. The predicted increase with age was curvilinear with significant variation between the seven breed categories. Mortality was higher in loose housing systems than in cages and variable within system, confirming previous reports. Cumulative mortality (CM) was higher in flocks with intact beaks (χ2 = 6.03; df 1; p = 0.014) than in those with trimmed beaks. Most data were available for free-range systems (2,823 flocks), where producer recorded CM at 60-80 weeks of age averaged 10% but with a range from 0% to 69.3%. Life cycle assessment showed that the main effect of increased levels of hen mortality is to increase the relative contribution of breeding overheads, so increasing environmental burdens per unit of production. Reducing CM to levels currently achieved by the 1st quartile could reduce flock greenhouse gas emissions by as much as 25%. Concurrently this would enhance hen welfare and better meet the expectation of egg consumers. More research to understand the genetic x environment interaction and detailed records of the causes of mortality is required so that improved genotypes can be developed for different systems and different breeds can be better managed within systems.

Elevated carbon dioxide increases salicylic acid in Glycine max.

PubMed

Casteel, Clare L; Segal, Lauren M; Niziolek, Olivia K; Berenbaum, May R; DeLucia, Evan H

2012-12-01

Concentrations of carbon dioxide (CO(2)) are increasing in the atmosphere, affecting soybean (Glycine max L.) phytohormone signaling and herbivore resistance. Whether the impact of elevated CO(2) on phytohormones and induced defenses is a generalized response within this species is an open question. We examined jasmonic acid (JA) and salicylic acid (SA) under ambient and elevated CO(2) concentrations with and without Japanese beetle (Popillia japonica Newman) damage and artificial damage across six soybean cultivars (HS93-4118, Pana, IA 3010, Loda, LN97-15076, and Dwight). Elevated CO(2) reduced constitutive levels of JA and related transcripts in some but not all soybean cultivars. In contrast to the variation in JA, constitutive levels of salicylic were increased universally among soybean cultivars grown under elevated CO(2). Variation in hormonal signaling may underpin observed variation in the response of insect herbivores and pathogens to plants grown under elevated CO(2).

Environmental Stochasticity and the Speed of Evolution

NASA Astrophysics Data System (ADS)

Danino, Matan; Kessler, David A.; Shnerb, Nadav M.

2018-03-01

Biological populations are subject to two types of noise: demographic stochasticity due to fluctuations in the reproductive success of individuals, and environmental variations that affect coherently the relative fitness of entire populations. The rate in which the average fitness of a community increases has been considered so far using models with pure demographic stochasticity; here we present some theoretical considerations and numerical results for the general case where environmental variations are taken into account. When the competition is pairwise, fitness fluctuations are shown to reduce the speed of evolution, while under global competition the speed increases due to environmental stochasticity.

Environmental Stochasticity and the Speed of Evolution

NASA Astrophysics Data System (ADS)

Danino, Matan; Kessler, David A.; Shnerb, Nadav M.

2018-07-01

Biological populations are subject to two types of noise: demographic stochasticity due to fluctuations in the reproductive success of individuals, and environmental variations that affect coherently the relative fitness of entire populations. The rate in which the average fitness of a community increases has been considered so far using models with pure demographic stochasticity; here we present some theoretical considerations and numerical results for the general case where environmental variations are taken into account. When the competition is pairwise, fitness fluctuations are shown to reduce the speed of evolution, while under global competition the speed increases due to environmental stochasticity.

Feedback enhanced plasma spray tool

DOEpatents

Gevelber, Michael Alan; Wroblewski, Donald Edward; Fincke, James Russell; Swank, William David; Haggard, Delon C.; Bewley, Randy Lee

2005-11-22

An improved automatic feedback control scheme enhances plasma spraying of powdered material through reduction of process variability and providing better ability to engineer coating structure. The present inventors discovered that controlling centroid position of the spatial distribution along with other output parameters, such as particle temperature, particle velocity, and molten mass flux rate, vastly increases control over the sprayed coating structure, including vertical and horizontal cracks, voids, and porosity. It also allows improved control over graded layers or compositionally varying layers of material, reduces variations, including variation in coating thickness, and allows increasing deposition rate. Various measurement and system control schemes are provided.

A new view of avian life-history evolution tested on an incubation paradox.

PubMed

Martin, Thomas E

2002-02-07

Viewing life-history evolution in birds based on an age-specific mortality framework can explain broad life-history patterns, including the long incubation periods in southern latitudes documented here. I show that incubation periods of species that are matched phylogenetically and ecologically between Argentina and Arizona are longer in Argentina. Long incubation periods have mystified scientists because they increase the accumulated risk of time-dependent mortality to young without providing a clear benefit. I hypothesize that parents of species with low adult mortality accept increased risk of mortality to their young from longer incubation if this allows reduced risk of mortality to themselves. During incubation, songbird parents can reduce risk of mortality to themselves by reducing nest attentiveness (percentage of time on the nest). Here I show that parents of species with lower adult mortality exhibit reduced nest attentiveness and that lower attentiveness is associated with longer incubation periods. However, the incubation period is also modified by juvenile mortality. Clutch size variation is also strongly correlated with age-specific mortality. Ultimately, adult and juvenile mortality explain variation in incubation and other life-history traits better than the historical paradigm.

Cardiomyocyte Ca2+ handling and structure is regulated by degree and duration of mechanical load variation.

PubMed

Ibrahim, Michael; Kukadia, Punam; Siedlecka, Urszula; Cartledge, James E; Navaratnarajah, Manoraj; Tokar, Sergiy; Van Doorn, Carin; Tsang, Victor T; Gorelik, Julia; Yacoub, Magdi H; Terracciano, Cesare M

2012-12-01

Cardiac transverse (t)-tubules are altered during disease and may be regulated by stretch-sensitive molecules. The relationship between variations in the degree and duration of load and t-tubule structure remains unknown, as well as its implications for local Ca(2+)-induced Ca(2+) release (CICR). Rat hearts were studied after 4 or 8 weeks of moderate mechanical unloading [using heterotopic abdominal heart-lung transplantation (HAHLT)] and 6 or 10 weeks of pressure overloading using thoracic aortic constriction. CICR, cell and t-tubule structure were assessed using confocal-microscopy, patch-clamping and scanning ion conductance microscopy. Moderate unloading was compared with severe unloading [using heart-only transplantation (HAHT)]. Mechanical unloading reduced cardiomyocyte volume in a time-dependent manner. Ca(2+) release synchronicity was reduced at 8 weeks moderate unloading only. Ca(2+) sparks increased in frequency and duration at 8 weeks of moderate unloading, which also induced t-tubule disorganization. Overloading increased cardiomyocyte volume and disrupted t-tubule morphology at 10 weeks but not 6 weeks. Moderate mechanical unloading for 4 weeks had milder effects compared with severe mechanical unloading (37% reduction in cell volume at 4 weeks compared to 56% reduction after severe mechanical unloading) and did not cause depression and delay of the Ca(2+) transient, increased Ca(2+) spark frequency or impaired t-tubule and cell surface structure. These data suggest that variations in chronic mechanical load influence local CICR and t-tubule structure in a time- and degree-dependent manner, and that physiological states of increased and reduced cell size, without pathological changes are possible. © 2012 The Authors Journal of Cellular and Molecular Medicine © 2012 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Reduced mtDNA copy number increases the sensitivity of tumor cells to chemotherapeutic drugs.

PubMed

Mei, H; Sun, S; Bai, Y; Chen, Y; Chai, R; Li, H

2015-04-02

Many cancer drugs are toxic to cells by activating apoptotic pathways. Previous studies have shown that mitochondria have key roles in apoptosis in mammalian cells, but the role of mitochondrial DNA (mtDNA) copy number variation in the pathogenesis of tumor cell apoptosis remains largely unknown. We used the HEp-2, HNE2, and A549 tumor cell lines to explore the relationship between mtDNA copy number variation and cell apoptosis. We first induced apoptosis in three tumor cell lines and one normal adult human skin fibroblast cell line (HSF) with cisplatin (DDP) or doxorubicin (DOX) treatment and found that the mtDNA copy number significantly increased in apoptotic tumor cells, but not in HSF cells. We then downregulated the mtDNA copy number by transfection with shRNA-TFAM plasmids or treatment with ethidium bromide and found that the sensitivity of tumor cells to DDP or DOX was significantly increased. Furthermore, we observed that levels of reactive oxygen species (ROS) increased significantly in tumor cells with lower mtDNA copy numbers, and this might be related to a low level of antioxidant gene expression. Finally, we rescued the increase of ROS in tumor cells with lipoic acid or N-acetyl-L-cysteine and found that the apoptosis rate decreased. Our studies suggest that the increase of mtDNA copy number is a self-protective mechanism of tumor cells to prevent apoptosis and that reduced mtDNA copy number increases ROS levels in tumor cells, increases the tumor cells' sensitivity to chemotherapeutic drugs, and increases the rate of apoptosis. This research provides evidence that mtDNA copy number variation might be a promising new therapeutic target for the clinical treatment of tumors.

Resist heating effect on e-beam mask writing at 75 kV and 60 A/cm2

NASA Astrophysics Data System (ADS)

Benes, Zdenek; Deverich, Christina; Huang, Chester; Lawliss, Mark

2003-12-01

Resist heating has been known to be one of the main contributors to local CD variation in mask patterning using variable shape e-beam tools. Increasingly complex mask patterns require increased number of shapes which drives the need for higher electron beam current densities to maintain reasonable write times. As beam current density is increased, CD error resulting from resist heating may become a dominating contributor to local CD variations. In this experimental study, the IBM EL4+ mask writer with high voltage and high current density has been used to quantitatively investigate the effect of resist heating on the local CD uniformity. ZEP 7000 and several chemically amplified resists have been evaluated under various exposure conditions (single-pass, multi-pass, variable spot size) and pattern densities. Patterns were designed specifically to allow easy measurement of local CD variations with write strategies designed to maximize the effect of resist heating. Local CD variations as high as 15 nm in 18.75 × 18.75 μm sub-field size have been observed for ZEP 7000 in a single-pass writing with full 1000 nm spots at 50% pattern density. This number can be reduced by increasing the number of passes or by decreasing the maximum spot size. The local CD variation has been reduced to as low as 2 nm for ZEP 7000 for the same pattern under modified exposure conditions. The effectiveness of various writing strategies is discussed as well as their possible deficiencies. Minimal or no resist heating effects have been observed for the chemically amplified resists studied. The results suggest that the resist heating effect can be well controlled by careful selection of the resist/process system and/or writing strategy and that resist heating does not have to pose a problem for high throughput e-beam mask making that requires high voltage and high current densities.

Reconstruction based finger-knuckle-print verification with score level adaptive binary fusion.

PubMed

Gao, Guangwei; Zhang, Lei; Yang, Jian; Zhang, Lin; Zhang, David

2013-12-01

Recently, a new biometrics identifier, namely finger knuckle print (FKP), has been proposed for personal authentication with very interesting results. One of the advantages of FKP verification lies in its user friendliness in data collection. However, the user flexibility in positioning fingers also leads to a certain degree of pose variations in the collected query FKP images. The widely used Gabor filtering based competitive coding scheme is sensitive to such variations, resulting in many false rejections. We propose to alleviate this problem by reconstructing the query sample with a dictionary learned from the template samples in the gallery set. The reconstructed FKP image can reduce much the enlarged matching distance caused by finger pose variations; however, both the intra-class and inter-class distances will be reduced. We then propose a score level adaptive binary fusion rule to adaptively fuse the matching distances before and after reconstruction, aiming to reduce the false rejections without increasing much the false acceptances. Experimental results on the benchmark PolyU FKP database show that the proposed method significantly improves the FKP verification accuracy.

Reducing variation in decomposition odour profiling using comprehensive two-dimensional gas chromatography.

PubMed

Perrault, Katelynn A; Stefanuto, Pierre-Hugues; Stuart, Barbara H; Rai, Tapan; Focant, Jean-François; Forbes, Shari L

2015-01-01

Challenges in decomposition odour profiling have led to variation in the documented odour profile by different research groups worldwide. Background subtraction and use of controls are important considerations given the variation introduced by decomposition studies conducted in different geographical environments. The collection of volatile organic compounds (VOCs) from soil beneath decomposing remains is challenging due to the high levels of inherent soil VOCs, further confounded by the use of highly sensitive instrumentation. This study presents a method that provides suitable chromatographic resolution for profiling decomposition odour in soil by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry using appropriate controls and field blanks. Logarithmic transformation and t-testing of compounds permitted the generation of a compound list of decomposition VOCs in soil. Principal component analysis demonstrated the improved discrimination between experimental and control soil, verifying the value of the data handling method. Data handling procedures have not been well documented in this field and standardisation would thereby reduce misidentification of VOCs present in the surrounding environment as decomposition byproducts. Uniformity of data handling and instrumental procedures will reduce analytical variation, increasing confidence in the future when investigating the effect of taphonomic variables on the decomposition VOC profile. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

HSP90 Shapes the Consequences of Human Genetic Variation.

PubMed

Karras, Georgios I; Yi, Song; Sahni, Nidhi; Fischer, Máté; Xie, Jenny; Vidal, Marc; D'Andrea, Alan D; Whitesell, Luke; Lindquist, Susan

2017-02-23

HSP90 acts as a protein-folding buffer that shapes the manifestations of genetic variation in model organisms. Whether HSP90 influences the consequences of mutations in humans, potentially modifying the clinical course of genetic diseases, remains unknown. By mining data for >1,500 disease-causing mutants, we found a strong correlation between reduced phenotypic severity and a dominant (HSP90 ≥ HSP70) increase in mutant engagement by HSP90. Examining the cancer predisposition syndrome Fanconi anemia in depth revealed that mutant FANCA proteins engaged predominantly by HSP70 had severely compromised function. In contrast, the function of less severe mutants was preserved by a dominant increase in HSP90 binding. Reducing HSP90's buffering capacity with inhibitors or febrile temperatures destabilized HSP90-buffered mutants, exacerbating FA-related chemosensitivities. Strikingly, a compensatory FANCA somatic mutation from an "experiment of nature" in monozygotic twins both prevented anemia and reduced HSP90 binding. These findings provide one plausible mechanism for the variable expressivity and environmental sensitivity of genetic diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Psychophysiological effects of self-regulation method: EEG frequency analysis and contingent negative variations.

PubMed

Ikemi, A

1988-01-01

Experiments were conducted to investigate the psychophysiological effects of self-regulation method (SRM), a newly developed method of self-control, using EEG frequency analysis and contingent negative variations (CNV). The results of the EEG frequency analysis showed that there is a significant increase in the percentage (power) of the theta-band and a significant decrease in the percentage (power) of the beta-band during SRM. Moreover, the results of an identical experiment conducted on subjects in a drowsy state showed that the changes in EEG frequencies during SRM can be differentiated from those of a drowsy state. Furthermore, experiments using CNV showed that there is a significant reduction of CNV amplitude during SRM. Despite the reduced amplitude during SRM, the number of errors in a task to evoke the CNV was reduced significantly without significant delay of reaction time. When an identical experiment was conducted in a drowsy state, CNV amplitude was reduced significantly, but reaction time and errors increased. From these experiments, the state of vigilance during SRM was discussed as a state of 'relaxed alertness'.

Accurate low-dose iterative CT reconstruction from few projections by Generalized Anisotropic Total Variation minimization for industrial CT.

PubMed

Debatin, Maurice; Hesser, Jürgen

2015-01-01

Reducing the amount of time for data acquisition and reconstruction in industrial CT decreases the operation time of the X-ray machine and therefore increases the sales. This can be achieved by reducing both, the dose and the pulse length of the CT system and the number of projections for the reconstruction, respectively. In this paper, a novel generalized Anisotropic Total Variation regularization for under-sampled, low-dose iterative CT reconstruction is discussed and compared to the standard methods, Total Variation, Adaptive weighted Total Variation and Filtered Backprojection. The novel regularization function uses a priori information about the Gradient Magnitude Distribution of the scanned object for the reconstruction. We provide a general parameterization scheme and evaluate the efficiency of our new algorithm for different noise levels and different number of projection views. When noise is not present, error-free reconstructions are achievable for AwTV and GATV from 40 projections. In cases where noise is simulated, our strategy achieves a Relative Root Mean Square Error that is up to 11 times lower than Total Variation-based and up to 4 times lower than AwTV-based iterative statistical reconstruction (e.g. for a SNR of 223 and 40 projections). To obtain the same reconstruction quality as achieved by Total Variation, the projection number and the pulse length, and the acquisition time and the dose respectively can be reduced by a factor of approximately 3.5, when AwTV is used and a factor of approximately 6.7, when our proposed algorithm is used.

Diurnal variation in ruminal pH on the digestibility of highly digestible perennial ryegrass during continuous culture fermentation.

PubMed

Wales, W J; Kolver, E S; Thorne, P L; Egan, A R

2004-06-01

Dairy cows grazing high-digestibility pastures exhibit pronounced diurnal variation in ruminal pH, with pH being below values considered optimal for digestion. Using a dual-flow continuous culture system, the hypothesis that minimizing diurnal variation in pH would improve digestion of pasture when pH was low, but not at a higher pH, was tested. Four treatments were imposed, with pH either allowed to exhibit normal diurnal variation around an average pH of 6.1 or 5.6, or maintained at constant pH. Digesta samples were collected during the last 3 d of each of four, 9-d experimental periods. A constant pH at 5.6 compared with a constant pH of 6.1 reduced the digestibility of organic matter (OM), neutral detergent (NDF), and acid detergent fiber (ADF) by 7, 14, and 21%, respectively. When pH was allowed to vary (averaging 5.6), digestion of OM, NDF, and ADF were reduced by 15,30, and 36%, respectively, compared with pH varying at 6.1. There was little difference in digestion parameters when pH was either constant or varied with an average pH of 6.1. However, when average pH was 5.6, maintaining a constant pH significantly increased digestion of OM, NDF, and ADF by 5, 25, and 24% compared with a pH that exhibited normal diurnal variation. These in vitro results show that gains in digestibility and potential milk production can be made by minimizing diurnal variation in ruminal pH, but only when ruminal pH is low (5.6). However, larger gains in productivity can be achieved by increasing average daily ruminal pH from 5.6 to 6.1.

Reducing Speckle In One-Look SAR Images

NASA Technical Reports Server (NTRS)

Nathan, K. S.; Curlander, J. C.

1990-01-01

Local-adaptive-filter algorithm incorporated into digital processing of synthetic-aperture-radar (SAR) echo data to reduce speckle in resulting imagery. Involves use of image statistics in vicinity of each picture element, in conjunction with original intensity of element, to estimate brightness more nearly proportional to true radar reflectance of corresponding target. Increases ratio of signal to speckle noise without substantial degradation of resolution common to multilook SAR images. Adapts to local variations of statistics within scene, preserving subtle details. Computationally simple. Lends itself to parallel processing of different segments of image, making possible increased throughput.

Effects of Spatial Variability of Soil Properties on the Triggering of Rainfall-Induced Shallow Landslides

NASA Astrophysics Data System (ADS)

Fan, Linfeng; Lehmann, Peter; Or, Dani

2015-04-01

Naturally-occurring spatial variations in soil properties (e.g., soil depth, moisture, and texture) affect key hydrological processes and potentially the mechanical response of soil to hydromechanical loading (relative to the commonly-assumed uniform soil mantle). We quantified the effects of soil spatial variability on the triggering of rainfall-induced shallow landslides at the hillslope- and catchment-scales, using a physically-based landslide triggering model that considers interacting soil columns with mechanical strength thresholds (represented by the Fiber Bundle Model). The spatial variations in soil properties are represented as Gaussian random distributions and the level of variation is characterized by the coefficient of variation and correlation lengths of soil properties (i.e., soil depth, soil texture and initial water content in this study). The impacts of these spatial variations on landslide triggering characteristics were measured by comparing the times to triggering and landslide volumes for heterogeneous soil properties and homogeneous cases. Results at hillslope scale indicate that for spatial variations of an individual property (without cross correlation), the increasing of coefficient of variation introduces weak spots where mechanical damage is accelerated and leads to earlier onset of landslide triggering and smaller volumes. Increasing spatial correlation length of soil texture and initial water content also induces early landslide triggering and small released volumes due to the transition of failure mode from brittle to ductile failure. In contrast, increasing spatial correlation length of soil depth "reduces" local steepness and postpones landslide triggering. Cross-correlated soil properties generally promote landslide initiation, but depending on the internal structure of spatial distribution of each soil property, landslide triggering may be reduced. The effects of cross-correlation between initial water content and soil texture were investigated in detail at the catchment scale by incorporating correlations of both variables with topography. Results indicate that the internal structure of the spatial distribution of each soil property together with their interplays determine the overall performance of the coupled spatial variability. This study emphasizes the importance of both the randomness and spatial structure of soil properties on landslide triggering and characteristics.

Trends and management of wolf-livestock conflicts in Minnesota

USGS Publications Warehouse

Fritts, S.H.; Paul, W.J.; Mech, L.D.; Scott, D.P.

1992-01-01

The nature and extent of wolf-livestock conflicts in Minnesota during 1975-86 was studied as part of a wolf depredation control program. The level of wolf (Canis lupus) depredation on livestock in Minnesota, as determined from the total number of complaints verified annually during 1975-86, showed a slight upward trend but did not increase significantly. A significant portion of the annual variation in verified complaints-perhaps the best index on severity of the depredation problem was explained by variation in severity of the winter before the depredation season (inverse relation). The addition of a time variable did not account for a significant portion of the remaining variation. Verified complaints of depredations averaged 30 per year, affecting an average of 21 farms (0.33% of producers) annually. Conflicts were highly seasonal and involved primarily cattle (mainly calves), sheep, and domestic turkeys. Annual variation in losses of sheep and turkeys was higher than for cattle. In recent years, sheep and turkey losses in two northwestern counties have increased; preventive control may be warranted in those areas. Site-specific trapping and removal of wolves in response to depredations was the primary control method, resulting in captures of 437 wolves in 12 depredation seasons. For the wolf range as a whole, no relation was found between wolf removal and subsequent depredation rates; however, wolf removal seemed to reduce depredations locally at some farms. When adults and yearlings were removed, no subsequent losses occurred in about 55% of instances; removal of young of the year reduced losses in 22%. Removal of breeding wolves did not reduce the incidence of subsequent losses more than removal of nonbreeding adults and yearlings did. The low number of conflicts for 1975-86 was remarkable considering the frequent contact between wolves and livestock. However, an update of complaints for 1987-89 revealed a definite upward trend in depredations (Epilogue). Improvements in farm management practices may reduce the present number of conflicts.

AFLP Variation in Populations of Podisus maculiventris

USDA-ARS?s Scientific Manuscript database

We are developing methods to reduce costs of mass producing beneficial insect species for biological control programs. One of our methods entails selecting beneficials for optimal production traits. Currently we are selecting for increased fecundity. Selection protocols, whether based on phenotyp...

Automated parton-shower variations in PYTHIA 8

DOE PAGES

Mrenna, S.; Skands, P.

2016-10-03

In the era of precision physics measurements at the LHC, efficient and exhaustive estimations of theoretical uncertainties play an increasingly crucial role. In the context of Monte Carlo (MC) event generators, the estimation of such uncertainties traditionally requires independent MC runs for each variation, for a linear increase in total run time. In this work, we report on an automated evaluation of the dominant (renormalization-scale and nonsingular) perturbative uncertainties in the pythia 8 event generator, with only a modest computational overhead. Each generated event is accompanied by a vector of alternative weights (one for each uncertainty variation), with each set separatelymore » preserving the total cross section. Explicit scale-compensating terms can be included, reflecting known coefficients of higher-order splitting terms and reducing the effect of the variations. In conclusion, the formalism also allows for the enhancement of rare partonic splittings, such as g→bb¯ and q→qγ, to obtain weighted samples enriched in these splittings while preserving the correct physical Sudakov factors.« less

The hydrostatic gradient, not light availability, drives height-related variation in Sequoia sempervirens (Cupressaceae) leaf anatomy.

PubMed

Oldham, Alana R; Sillett, Stephen C; Tomescu, Alexandru M F; Koch, George W

2010-07-01

Leaves at the tops of most trees are smaller, thicker, and in many other ways different from leaves on the lowermost branches. This height-related variation in leaf structure has been explained as acclimation to differing light environments and, alternatively, as a consequence of hydrostatic, gravitational constraints on turgor pressure that reduce leaf expansion. • To separate hydrostatic effects from those of light availability, we used anatomical analysis of height-paired samples from the inner and outer tree crowns of tall redwoods (Sequoia sempervirens). • Height above the ground correlates much more strongly with leaf anatomy than does light availability. Leaf length, width, and mesophyll porosity all decrease linearly with height and help explain increases in leaf-mass-to-area ratio and decreases in both photosynthetic capacity and internal gas-phase conductance with increasing height. Two functional traits-leaf thickness and transfusion tissue-also increase with height and may improve water-stress tolerance. Transfusion tissue area increases enough that whole-leaf vascular volume does not change significantly with height in most trees. Transfusion tracheids become deformed with height, suggesting they may collapse under water stress and act as a hydraulic buffer that improves leaf water status and reduces the likelihood of xylem dysfunction. • That such variation in leaf structure may be caused more by gravity than by light calls into question use of the terms "sun" and "shade" to describe leaves at the tops and bottoms of tall tree crowns.

Buoyancy under Control: Underwater Locomotor Performance in a Deep Diving Seabird Suggests Respiratory Strategies for Reducing Foraging Effort

PubMed Central

Cook, Timothée R.; Kato, Akiko; Tanaka, Hideji; Ropert-Coudert, Yan; Bost, Charles-André

2010-01-01

Background Because they have air stored in many body compartments, diving seabirds are expected to exhibit efficient behavioural strategies for reducing costs related to buoyancy control. We study the underwater locomotor activity of a deep-diving species from the Cormorant family (Kerguelen shag) and report locomotor adjustments to the change of buoyancy with depth. Methodology/Principal Findings Using accelerometers, we show that during both the descent and ascent phases of dives, shags modelled their acceleration and stroking activity on the natural variation of buoyancy with depth. For example, during the descent phase, birds increased swim speed with depth. But in parallel, and with a decay constant similar to the one in the equation explaining the decrease of buoyancy with depth, they decreased foot-stroke frequency exponentially, a behaviour that enables birds to reduce oxygen consumption. During ascent, birds also reduced locomotor cost by ascending passively. We considered the depth at which they started gliding as a proxy to their depth of neutral buoyancy. This depth increased with maximum dive depth. As an explanation for this, we propose that shags adjust their buoyancy to depth by varying the amount of respiratory air they dive with. Conclusions/Significance Calculations based on known values of stored body oxygen volumes and on deep-diving metabolic rates in avian divers suggest that the variations of volume of respiratory oxygen associated with a respiration mediated buoyancy control only influence aerobic dive duration moderately. Therefore, we propose that an advantage in cormorants - as in other families of diving seabirds - of respiratory air volume adjustment upon diving could be related less to increasing time of submergence, through an increased volume of body oxygen stores, than to reducing the locomotor costs of buoyancy control. PMID:20352122

Vegetation Interaction Enhances Interdecadal Climate Variability in the Sahel

NASA Technical Reports Server (NTRS)

Zeng, Ning; Neelin, J. David; Lau, William K.-M.

1999-01-01

The role of naturally varying vegetation in influencing the climate variability in the Sahel is explored in a coupled atmosphere-land-vegetation model. The Sahel rainfall variability is influenced by sea surface temperature (SST) variations in the oceans. Land-surface feedback is found to increase this variability both on interannual and interdecadal time scales. Interactive vegetation enhances the interdecadal variation significantly, but can reduce year to year variability due to a phase lag introduced by the relatively slow vegetation adjustment time. Variations in vegetation accompany the changes in rainfall, in particular, the multi-decadal drying trend from the 1950s to the 80s.

Adaptive potential of northernmost tree populations to climate change, with emphasis on Scots pine (Pinus sylvestris L.).

PubMed

Savolainen, Outi; Kujala, Sonja T; Sokol, Catherina; Pyhäjärvi, Tanja; Avia, Komlan; Knürr, Timo; Kärkkäinen, Katri; Hicks, Sheila

2011-01-01

The adaptive potential of the northernmost Pinus sylvestris L. (and other northern tree) populations is considered by examining first the current patterns of quantitative genetic adaptive traits, which show high population differentiation and clines. We then consider the postglacial history of the populations using both paleobiological and genetic data. The current patterns of diversity at nuclear genes suggest that the traces of admixture are mostly visible in mitochondrial DNA variation patterns. There is little evidence of increased diversity due to admixture between an eastern and western colonization lineage, but no signal of reduced diversity (due to sequential bottlenecks) either. Quantitative trait variation in the north is not associated with the colonizing lineages. The current clines arose rapidly and may be based on standing genetic variation. The initial phenotypic response of Scots pine in the north is predicted to be increased survival and growth. The genetic responses are examined based on quantitative genetic predictions of sustained selection response and compared with earlier simulation results that have aimed at more ecological realism. The phenotypic responses of increased growth and survival reduce the opportunity for selection and delay the evolutionary responses. The lengthening of the thermal growing period also causes selection on the critical photoperiod in the different populations. Future studies should aim at including multiple ecological and genetic factors in evaluating potential responses.

Evolutionary conservatism explains increasing relatedness of plant communities along a flooding gradient.

PubMed

Tanentzap, Andrew J; Lee, William G

2017-01-01

Abiotic filters have been found either to increase or reduce evolutionary relatedness in plant communities, making it difficult to generalize responses of this major feature of biodiversity to future environmental change. Here, we hypothesized that the responses of phylogenetic structure to environmental change ultimately depend on how species have evolved traits for tolerating the resulting abiotic changes. Working within ephemeral wetlands, we tested whether species were increasingly related as flooding duration intensified. We also identified the mechanisms underlying increased relatedness by measuring root aerenchyma volume (RAV), a trait which promotes waterlogging tolerance. We found that species-specific responses to flooding explained most of the variation in occurrence for 63 vascular plant species across 5170 plots. For a subset of 22 species, we attributed these responses to variation in RAV. Large RAV specifically increased occurrence when flooding lasted for longer time periods, because large RAV reduced above-ground biomass loss. As large RAV was evolutionarily conserved within obligate wetland species, communities were more phylogenetically related as flooding increased. Our study shows how reconstructing the evolutionary history of traits that influence the responses of species to environmental change can help to predict future patterns in phylogenetic structure. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Enhanced Constraints for Accurate Lower Bounds on Many-Electron Quantum Energies from Variational Two-Electron Reduced Density Matrix Theory.

PubMed

Mazziotti, David A

2016-10-07

A central challenge of physics is the computation of strongly correlated quantum systems. The past ten years have witnessed the development and application of the variational calculation of the two-electron reduced density matrix (2-RDM) without the wave function. In this Letter we present an orders-of-magnitude improvement in the accuracy of 2-RDM calculations without an increase in their computational cost. The advance is based on a low-rank, dual formulation of an important constraint on the 2-RDM, the T2 condition. Calculations are presented for metallic chains and a cadmium-selenide dimer. The low-scaling T2 condition will have significant applications in atomic and molecular, condensed-matter, and nuclear physics.

Enhanced Constraints for Accurate Lower Bounds on Many-Electron Quantum Energies from Variational Two-Electron Reduced Density Matrix Theory

NASA Astrophysics Data System (ADS)

Mazziotti, David A.

2016-10-01

A central challenge of physics is the computation of strongly correlated quantum systems. The past ten years have witnessed the development and application of the variational calculation of the two-electron reduced density matrix (2-RDM) without the wave function. In this Letter we present an orders-of-magnitude improvement in the accuracy of 2-RDM calculations without an increase in their computational cost. The advance is based on a low-rank, dual formulation of an important constraint on the 2-RDM, the T 2 condition. Calculations are presented for metallic chains and a cadmium-selenide dimer. The low-scaling T 2 condition will have significant applications in atomic and molecular, condensed-matter, and nuclear physics.

Does stronger pollen competition improve offspring fitness when pollen load does not vary?

PubMed

Pélabon, Christophe; Hennet, Lauriane; Bolstad, Geir H; Albertsen, Elena; Opedal, Øystein H; Ekrem, Runa K; Armbruster, W Scott

2016-03-01

Competition among pollen grains from a single donor is expected to increase the quality of the offspring produced because of the recessive deleterious alleles expressed during pollen-tube growth. However, evidence for such an effect is inconclusive; a large number of studies suffer from confounding variation in pollen competition with variation in pollen load. In this study, we tested the effect of pollen competition on offspring performance independently of pollen-load variation. We compared seed mass and early seedling performance in Dalechampia scandens (Euphorbiaceae) between crosses in which variation in pollen competition was achieved, without variation in pollen load, by manipulating the dispersion of pollen grains on the stigmas. Despite a large sample size (211 crosses on 20 maternal plants), we failed to find an effect of pollen competition on seed characteristics or early seedling performance. Paternal effects were always limited, and pollen competition never reduced the within-father (residual) variance. These results suggest that limited within-donor variation in genetic quality of pollen grains reduces the potential benefits of pollen competition in the study population. The lack of paternal effects on early sporophyte performance further suggests that benefits of pollen competition among pollen from multiple donors should be limited as well, and it raises questions about the significance of pollen competition as a mechanism of sexual selection. © 2016 Botanical Society of America.

Emergency medicine: an operations management view.

PubMed

Soremekun, Olan A; Terwiesch, Christian; Pines, Jesse M

2011-12-01

Operations management (OM) is the science of understanding and improving business processes. For the emergency department (ED), OM principles can be used to reduce and alleviate the effects of crowding. A fundamental principle of OM is the waiting time formula, which has clear implications in the ED given that waiting time is fundamental to patient-centered emergency care. The waiting time formula consists of the activity time (how long it takes to complete a process), the utilization rate (the proportion of time a particular resource such a staff is working), and two measures of variation: the variation in patient interarrival times and the variation in patient processing times. Understanding the waiting time formula is important because it presents the fundamental parameters that can be managed to reduce waiting times and length of stay. An additional useful OM principle that is applicable to the ED is the efficient frontier. The efficient frontier compares the performance of EDs with respect to two dimensions: responsiveness (i.e., 1/wait time) and utilization rates. Some EDs may be "on the frontier," maximizing their responsiveness at their given utilization rates. However, most EDs likely have opportunities to move toward the frontier. Increasing capacity is a movement along the frontier and to truly move toward the frontier (i.e., improving responsiveness at a fixed capacity), we articulate three possible options: eliminating waste, reducing variability, or increasing flexibility. When conceptualizing ED crowding interventions, these are the major strategies to consider. © 2011 by the Society for Academic Emergency Medicine.

More efficient optimization of long-term water supply portfolios

NASA Astrophysics Data System (ADS)

Kirsch, Brian R.; Characklis, Gregory W.; Dillard, Karen E. M.; Kelley, C. T.

2009-03-01

The use of temporary transfers, such as options and leases, has grown as utilities attempt to meet increases in demand while reducing dependence on the expansion of costly infrastructure capacity (e.g., reservoirs). Earlier work has been done to construct optimal portfolios comprising firm capacity and transfers, using decision rules that determine the timing and volume of transfers. However, such work has only focused on the short-term (e.g., 1-year scenarios), which limits the utility of these planning efforts. Developing multiyear portfolios can lead to the exploration of a wider range of alternatives but also increases the computational burden. This work utilizes a coupled hydrologic-economic model to simulate the long-term performance of a city's water supply portfolio. This stochastic model is linked with an optimization search algorithm that is designed to handle the high-frequency, low-amplitude noise inherent in many simulations, particularly those involving expected values. This noise is detrimental to the accuracy and precision of the optimized solution and has traditionally been controlled by investing greater computational effort in the simulation. However, the increased computational effort can be substantial. This work describes the integration of a variance reduction technique (control variate method) within the simulation/optimization as a means of more efficiently identifying minimum cost portfolios. Random variation in model output (i.e., noise) is moderated using knowledge of random variations in stochastic input variables (e.g., reservoir inflows, demand), thereby reducing the computing time by 50% or more. Using these efficiency gains, water supply portfolios are evaluated over a 10-year period in order to assess their ability to reduce costs and adapt to demand growth, while still meeting reliability goals. As a part of the evaluation, several multiyear option contract structures are explored and compared.

Omentin-1 levels are reduced by pharmacologic doses of leptin, but remain unaffected by energy deprivation and display no day-night variation.

PubMed

Hamnvik, Ole-Petter Riksfjord; Thakkar, Bindiya; Chamberland, John; Aronis, Konstantinos; Schneider, Benjamin; Mantzoros, Christos S

2015-02-01

To study the day-night variation of omentin-1 levels and assess whether leptin and/or short- and long-term energy deprivation alter circulating omentin-1 levels via cytokines. Omentin-1 levels were measured hourly in serum samples from six healthy men to evaluate for day-night variation. To study effects of acute energy deprivation and of leptin administration, eight healthy subjects were studied in the fasting state for 72 h with administration of either placebo or metreleptin (recombinant human leptin) in physiologic replacement doses. We evaluated the effect of leptin in pharmacologic doses on serum omentin-1 and cytokine levels, as well as on omentin-1 levels in ex vivo omental adipose tissue, in 15 healthy volunteers. To study the effect of chronic energy deprivation and weight loss on omentin-1 levels, we followed 18 obese subjects for 12 months who underwent bariatric surgery. There is no day-night variation in omentin-1 levels. Short-term and chronic energy deprivation, as well as ex vivo leptin administration and physiologic replacement doses of leptin, do not alter omentin-1 levels; pharmacologic doses of metreleptin reduce omentin-1 levels, whereas levels of tumor necrosis factor-α receptor II and interleukin-6 tend to increase. Omentin-1 levels are reduced by pharmacologic doses of metreleptin independent of effects on cytokine levels.

Fitness variation in response to artificial selection for reduced cell area, cell number and wing area in natural populations of Drosophila melanogaster.

PubMed

Trotta, Vincenzo; Calboli, Federico C F; Ziosi, Marcello; Cavicchi, Sandro

2007-08-16

Genetically based body size differences are naturally occurring in populations of Drosophila melanogaster, with bigger flies in the cold. Despite the cosmopolitan nature of body size clines in more than one Drosophila species, the actual selective mechanisms controlling the genetic basis of body size variation are not fully understood. In particular, it is not clear what the selective value of cell size and cell area variation exactly is. In the present work we determined variation in viability, developmental time and larval competitive ability in response to crowding at two temperatures after artificial selection for reduced cell area, cell number and wing area in four different natural populations of D. melanogaster. No correlated effect of selection on viability or developmental time was observed among all selected populations. An increase in competitive ability in one thermal environment (18 degrees C) under high larval crowding was observed as a correlated response to artificial selection for cell size. Viability and developmental time are not affected by selection for the cellular component of body size, suggesting that these traits only depend on the contingent genetic makeup of a population. The higher larval competitive ability shown by populations selected for reduced cell area seems to confirm the hypothesis that cell area mediated changes have a relationship with fitness, and might be the preferential way to change body size under specific circumstances.

Altitudinal variation of demographic life-history traits does not mimic latitudinal variation in natterjack toads (Bufo calamita).

PubMed

Oromi, Neus; Sanuy, Delfi; Sinsch, Ulrich

2012-02-01

In anuran amphibians, age- and size-related life-history traits vary along latitudinal and altiudinal gradients. In the present study, we tested the hypothesis that altitudinal and latitudinal effects cause similar responses by assessing demographic life-history traits in nine Bufo calamita populations inhabiting elevations from sea level to 2270 m. Skeletochronologically determined age at maturity and longevity increased at elevations exceeding 2000 m, but female potential reproductive lifespan (PRLS) did not increase with altitude, as it did with latitude. Integrating the available evidence, it was found that lifetime fecundity of natterjacks decreased at the upper altitudinal range because PRLS was about the same as in lowland populations but females were smaller. In contrast, small size of northern females was compensated for by increased PRLS which minimised latitudinal variation of lifetime fecundity. Thus, this study provides evidence that altitudinal effects on life-history traits do not mimic latitudinal effects. Life-history trait variation along the altitudinal gradient seems to respond directly to the shortening of the annual activity period. As there is no evidence for increasing mortality in highland populations, reduced lifetime fecundity may be the ultimate reason for the natterjacks' inability to colonise elevations exceeding 2500 m. Copyright © 2011 Elsevier GmbH. All rights reserved.

Flip-flop logic circuit based on fully solution-processed organic thin film transistor devices with reduced variations in electrical performance

NASA Astrophysics Data System (ADS)

Takeda, Yasunori; Yoshimura, Yudai; Adib, Faiz Adi Ezarudin Bin; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo

2015-04-01

Organic reset-set (RS) flip-flop logic circuits based on pseudo-CMOS inverters have been fabricated using full solution processing at a relatively low process temperatures of 150 °C or less. The work function for printed silver electrodes was increased from 4.7 to 5.4 eV through surface modification with a self-assembled monolayer (SAM) material. A bottom-gate, bottom-contact organic thin-film transistor (OTFT) device using a solution-processable small-molecular semiconductor material exhibited field-effect mobility of 0.40 cm2 V-1 s-1 in the saturation region and a threshold voltage (VTH) of -2.4 V in ambient air operation conditions. In order to reduce the variations in mobility and VTH, we designed a circuit with six transistors arranged in parallel, in order to average out their electrical characteristics. As a result, we have succeeded in reducing these variations without changing the absolute values of the mobility and VTH. The fabricated RS flip-flop circuits were functioned well and exhibited short delay times of 3.5 ms at a supply voltage of 20 V.

Local, national, and service component cost variations in the management of low back pain: Considerations for the clinician.

PubMed

Babu, Ashwin N; McCormick, Zachary; Kennedy, David J; Press, Joel

2016-11-21

In the past two decades, the cost associated with managing low back pain has increased significantly. Improved consciousness of how clinicians utilize resources when managing low back pain is necessary in the current economic climate. The goal of this review is to examine the component costs associated with managing low back pain and provide practical solutions for reducing healthcare costs. This is accomplished by utilizing examples from a major metropolitan area with several major academic institutions and private health care centers. It is clear that there is considerable local and national variation in the component costs of managing low back pain, including physician visits, imaging studies, medications, and therapy services. By being well informed about these variations in one's environment, clinicians and patients alike can make strides towards reducing the financial impact of low back pain. Investigation of the cost discrepancies for services within one's community of practice is important. Improved public access to both cost and outcomes data is needed.

Optimization of Energy Consumption and Mass Transfer Parameters in a Surface Aeration Vessel.

PubMed

Mohammadpour, A; AkhavanBehabadi, M A; Ebrahimzadeh, M; Raisee, M; MajdiNasab, A R; Nosrati, M; Mousavi, S M

2016-04-01

This paper reports tests on a lab-scale surface aeration vessel was equipped with a Rushton turbine to examine its performance in terms of standard aeration efficiency (SAE), mixing time, and void fraction characteristics. These characteristics were investigated by tests using variations of rotor speed, impeller immersion depth, and water level. Results showed that variation of impeller immersion depth had a greater effect on the SAE compared to variation of water level. Moreover, the SAE increased with rotor speeds up to about 150 to 200 rpm and then decreased. In addition, void fraction improved by impeller immersion depth and rotor speed enhancement; however, mixing time and power number were reduced as rotor speed increased. According to the response surface methodology statistical optimizations, optimum values for rotor speed, impeller immersion depth, and water level were 168.90 rpm, 25 mm, and 30 cm, respectively, to achieve the maximum value of SAE.

The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length

PubMed Central

Cook, Daniel E.; Zdraljevic, Stefan; Tanny, Robyn E.; Seo, Beomseok; Riccardi, David D.; Noble, Luke M.; Rockman, Matthew V.; Alkema, Mark J.; Braendle, Christian; Kammenga, Jan E.; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C.

2016-01-01

Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans. PMID:27449056

Disrupting evolutionary processes: the effect of habitat fragmentation on collared lizards in the Missouri Ozarks.

PubMed

Templeton, A R; Robertson, R J; Brisson, J; Strasburg, J

2001-05-08

Humans affect biodiversity at the genetic, species, community, and ecosystem levels. This impact on genetic diversity is critical, because genetic diversity is the raw material of evolutionary change, including adaptation and speciation. Two forces affecting genetic variation are genetic drift (which decreases genetic variation within but increases genetic differentiation among local populations) and gene flow (which increases variation within but decreases differentiation among local populations). Humans activities often augment drift and diminish gene flow for many species, which reduces genetic variation in local populations and prevents the spread of adaptive complexes outside their population of origin, thereby disrupting adaptive processes both locally and globally within a species. These impacts are illustrated with collared lizards (Crotaphytus collaris) in the Missouri Ozarks. Forest fire suppression has reduced habitat and disrupted gene flow in this lizard, thereby altering the balance toward drift and away from gene flow. This balance can be restored by managed landscape burns. Some have argued that, although human-induced fragmentation disrupts adaptation, it will also ultimately produce new species through founder effects. However, population genetic theory and experiments predict that most fragmentation events caused by human activities will facilitate not speciation, but local extinction. Founder events have played an important role in the macroevolution of certain groups, but only when ecological opportunities are expanding rather than contracting. The general impact of human activities on genetic diversity disrupts or diminishes the capacity for adaptation, speciation, and macroevolutionary change. This impact will ultimately diminish biodiversity at all levels.

A novel method of reducing agent contacting pattern for metal ceramic composite membrane fabrication

NASA Astrophysics Data System (ADS)

Agarwal, Amrita; Pujari, Murali; Uppaluri, Ramgopal; Verma, Anil

2014-11-01

Deliberating upon process modifications for surfactant induced electroless plating (SIEP), this article highlights the plating bath performance characteristics for two distinct reducing agent contacting modes (bulk and drop wise). Eventually, the effect of reducing agent concentration (50, 100, 200% excess) suitable for electroless plating bath for a nickel concentration of 0.08 mol/L was investigated. Finally, the compatibility of variation in nickel concentration (0.08-0.24 mol/L) with respect to variation in reducing agent concentration (50, 100, 200% excess) was investigated. LPSA, BET, FTIR, XRD, FESEM and nitrogen permeation experiments were used for surface and physical characterization. It was observed that for the bulk addition of reducing agent, the PPD values were 84.5% which increased to 89.3% for dropwise addition case. Thus the optimal combinations of SIEP process parameters were identified as 0.08 mol/L of nickel metal solution concentration with 100% excess drop-wise reducing agent. These conditions provided a plating rate of 5.5 × 10-5 mol/m2 s, PPD of 89.3% and a metal film thickness of 15.7 μm respectively after 12 h of sequential plating.

Differences in the volume of services and in prices drive big variations in Medicaid spending among US states and regions.

PubMed

Gilmer, Todd P; Kronick, Richard G

2011-07-01

It is well known that Medicaid spending per beneficiary varies widely across states. However, less is known about the cause of this variation, or about whether increased spending is associated with better outcomes. In this article we describe and analyze sources of interstate variation in Medicaid spending over several years. We find substantial variations both in the volume of services and in prices. Overall, per capita spending in the ten highest-spending states was $1,650 above the average national per capita spending, of which $1,186, or 72 percent, was due to the volume of services delivered. Spending in the ten lowest-spending states was $1,161 below the national average, of which $672, or 58 percent, was due to volume. In the mid-Atlantic region, increased price and volume resulted in the most expensive care among regions, whereas reduced price and volume in the South Central region resulted in the least expensive care among regions. Understanding these variations in greater detail should help improve the quality and efficiency of care-a task that will become more important as Medicaid is greatly expanded under the Affordable Care Act of 2010.

Small-scale shifting mosaics of two dominant grassland species: the possible role of soil-borne pathogens.

PubMed

Olff, H; Hoorens, B; de Goede, R G M; van der Putten, W H; Gleichman, J M

2000-10-01

We analyzed the dynamics of dominant plant species in a grazed grassland over 17 years, and investigated whether local shifts in these dominant species, leading to vegetation mosaics, could be attributed to interactions between plants and soil-borne pathogens. We found that Festuca rubra and Carex arenaria locally alternated in abundance, with different sites close together behaving out of phase, resulting in a shifting mosaic. The net effect of killing all soil biota on the growth of these two species was investigated in a greenhouse experiment using gamma radiation, controlling for possible effects of sterilization on soil chemistry. Both plant species showed a strong net positive response to soil sterilization, indicating that pathogens (e.g., nematodes, pathogenic fungi) outweighed the effect of mutualists (e.g., mycorrhizae). This positive growth response towards soil sterilization appeared not be due to effects of sterilization on soil chemistry. Growth of Carex was strongly reduced by soil-borne pathogens (86% reduction relative to its growth on sterilized soil) on soil from a site where this species decreased during the last decade (and Festuca increased), while it was reduced much less (50%) on soil from a nearby site where it increased in abundance during the last decade. Similarly, Festuca was reduced more (67%) on soil from the site where it decreased (and Carex increased) than on soil from the site where it increased (55%, the site where Carex decreased). Plant-feeding nematodes showed high small-scale variation in densities, and we related this variation to the observed growth reductions in both plant species. Carex growth on unsterilized soil was significantly more reduced at higher densities of plant-feeding nematodes, while the growth reduction in Festuca was independent of plant-feeding nematode densities. At high plant-feeding nematode densities, growth of Carex was reduced more than Festuca, while at low nematode densities the opposite was found. Each plant species thus seems to be affected by different (groups of) soil-borne pathogens. The resulting interaction web of plants and soil-borne pathogens is discussed. We hypothesize that soil disturbances by digging ants and rabbits may explain the small-scale variation in nematode densities, by locally providing "fresh" sand. We conclude that soil-borne pathogens may contribute to plant diversity and spatial mosaics of plants in grasslands.

Oxytocin receptor gene variation predicts subjective responses to MDMA.

PubMed

Bershad, Anya K; Weafer, Jessica J; Kirkpatrick, Matthew G; Wardle, Margaret C; Miller, Melissa A; de Wit, Harriet

2016-12-01

3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") enhances desire to socialize and feelings of empathy, which are thought to be related to increased oxytocin levels. Thus, variation in the oxytocin receptor gene (OXTR) may influence responses to the drug. Here, we examined the influence of a single OXTR nucleotide polymorphism (SNP) on responses to MDMA in humans. Based on findings that carriers of the A allele at rs53576 exhibit reduced sensitivity to oxytocin-induced social behavior, we hypothesized that these individuals would show reduced subjective responses to MDMA, including sociability. In this three-session, double blind, within-subjects study, healthy volunteers with past MDMA experience (N = 68) received a MDMA (0, 0.75 mg/kg, and 1.5 mg/kg) and provided self-report ratings of sociability, anxiety, and drug effects. These responses were examined in relation to rs53576. MDMA (1.5 mg/kg) did not increase sociability in individuals with the A/A genotype as it did in G allele carriers. The genotypic groups did not differ in responses at the lower MDMA dose, or in cardiovascular or other subjective responses. These findings are consistent with the idea that MDMA-induced sociability is mediated by oxytocin, and that variation in the oxytocin receptor gene may influence responses to the drug.

Oxytocin receptor gene variation predicts subjective responses to MDMA

PubMed Central

Bershad, Anya K.; Weafer, Jessica J.; Kirkpatrick, Matthew G.; Wardle, Margaret C.; Miller, Melissa A.; de Wit, Harriet

2016-01-01

3,4-Methylenedioxymethamphetamine (MDMA, “ecstasy”) enhances desire to socialize and feelings of empathy, which are thought to be related to increased oxytocin levels. Thus, variation in the oxytocin receptor gene (OXTR) may influence responses to the drug. Here, we examined the influence of a single OXTR nucleotide polymorphism (SNP) on responses to MDMA in humans. Based on findings that carriers of the A allele at rs53576 exhibit reduced sensitivity to oxytocin-induced social behavior, we hypothesized that these individuals would show reduced subjective responses to MDMA, including sociability. In this three-session, double blind, within-subjects study, healthy volunteers with past MDMA experience (N = 68) received a MDMA (0, 0.75 mg/kg, and 1.5 mg/kg) and provided self-report ratings of sociability, anxiety, and drug effects. These responses were examined in relation to rs53576. MDMA (1.5 mg/kg) did not increase sociability in individuals with the A/A genotype as it did in G allele carriers. The genotypic groups did not differ in responses at the lower MDMA dose, or in cardiovascular or other subjective responses. These findings are consistent with the idea that MDMA-induced sociability is mediated by oxytocin, and that variation in the oxytocin receptor gene may influence responses to the drug. PMID:26787430

Genomics and metabolomics of post-weaning return to estrus

USDA-ARS?s Scientific Manuscript database

The weaning-to-estrus interval is a multifaceted trait that has the potential to substantially improve production efficiency in today's global swine industry, if variation in this measure can be reduced. Systems-biology approaches should help close the knowledge gap and increase selection tools and ...

Chlorophyll Can Be Reduced in Crop Canopies with Little Penalty to Photosynthesis1[OPEN

PubMed Central

Drewry, Darren T.; VanLoocke, Andy; Cho, Young B.

2018-01-01

The hypothesis that reducing chlorophyll content (Chl) can increase canopy photosynthesis in soybeans was tested using an advanced model of canopy photosynthesis. The relationship among leaf Chl, leaf optical properties, and photosynthetic biochemical capacity was measured in 67 soybean (Glycine max) accessions showing large variation in leaf Chl. These relationships were integrated into a biophysical model of canopy-scale photosynthesis to simulate the intercanopy light environment and carbon assimilation capacity of canopies with wild type, a Chl-deficient mutant (Y11y11), and 67 other mutants spanning the extremes of Chl to quantify the impact of variation in leaf-level Chl on canopy-scale photosynthetic assimilation and identify possible opportunities for improving canopy photosynthesis through Chl reduction. These simulations demonstrate that canopy photosynthesis should not increase with Chl reduction due to increases in leaf reflectance and nonoptimal distribution of canopy nitrogen. However, similar rates of canopy photosynthesis can be maintained with a 9% savings in leaf nitrogen resulting from decreased Chl. Additionally, analysis of these simulations indicate that the inability of Chl reductions to increase photosynthesis arises primarily from the connection between Chl and leaf reflectance and secondarily from the mismatch between the vertical distribution of leaf nitrogen and the light absorption profile. These simulations suggest that future work should explore the possibility of using reduced Chl to improve canopy performance by adapting the distribution of the “saved” nitrogen within the canopy to take greater advantage of the more deeply penetrating light. PMID:29061904

Niemann-Pick C1 modulates hepatic triglyceride metabolism and its genetic variation contributes to serum triglyceride levels.

PubMed

Uronen, Riikka-Liisa; Lundmark, Per; Orho-Melander, Marju; Jauhiainen, Matti; Larsson, Kristina; Siegbahn, Agneta; Wallentin, Lars; Zethelius, Björn; Melander, Olle; Syvänen, Ann-Christine; Ikonen, Elina

2010-08-01

To study how Niemann-Pick disease type C1 (NPC1) influences hepatic triacylglycerol (TG) metabolism and to determine whether this is reflected in circulating lipid levels. In Npc1(-/-) mice, the hepatic cholesterol content is increased but the TG content is decreased. We investigated lipid metabolism in Npc1(-/-) mouse hepatocytes and the association of NPC1 single-nucleotide polymorphisms with circulating TGs in humans. TGs were reduced in Npc1(-/-) mouse serum and hepatocytes. In Npc1(-/-) hepatocytes, the incorporation of [3H]oleic acid and [3H]acetate into TG was decreased, but shunting of oleic acid- or acetate-derived [3H]carbons into cholesterol was increased. Inhibition of cholesterol synthesis normalized TG synthesis, content, and secretion in Npc1(-/-) hepatocytes, suggesting increased hepatic cholesterol neogenesis as a cause for the reduced TG content and secretion. We found a significant association between serum TG levels and 5 common NPC1 single-nucleotide polymorphisms in a cohort of 1053 men, with the lowest P=8.7 x 10(-4) for the single-nucleotide polymorphism rs1429934. The association between the rs1429934 A allele and higher TG levels was replicated in 2 additional cohorts, which included 8041 individuals. This study provides evidence of the following: (1) in mice, loss of NPC1 function reduces hepatocyte TG content and secretion by increasing the metabolic flux of carbons into cholesterol synthesis; and (2) common variation in NPC1 contributes to serum TG levels in humans.

Dynamical influences on the moment of inertia tensor from lateral viscosity variations inferred from seismic tomographic models

NASA Technical Reports Server (NTRS)

Zhang, Shuxia; Yuen, David A.

1994-01-01

We have investigated the influences of lateral variations of viscosity on the moment of inertia tensor from viscous flows due to the density anomalies in the mantle inferred from seismic tomographic models. The scaling relations between the density and the seismic anomalies is taken as either a constant or a function increasing with depth in accord with the recent high-pressure experimental studies. The viscosity is taken as an exponential function of the 3D density anomaly. In models with an isoviscous background, the effects on the perturbed moment of inertia tensor from the lateral viscosity variations are smaller than those due to variations in the radial viscosity profiles. In mantle models with a background viscosity increasing with depth, the influences of the lateral viscosity variations are significant. The most striking feature in the latter case is that the two off-diagonal elements delta I(sub xz) and delta I(sub yz) in the inertia tensor exhibit greatest sensitivity to lateral variations of the viscosity. While the other elements of the inertia change by only about a few tens of percent in the range of lateral viscosity contrast considered (less than 300), delta I(sub xz) and delta I(sub yz) can vary up to 40 times even with a change in sign, depending on the radial viscosity stratification and the location of the strongest lateral variations. The increase in the velocity-density scaling relation with depth can reduce the influences of the lateral viscosity variations, but it does not change the overall sensitive nature of delta I(sub xz) and delta I(sub yz). This study demonstrates clearly that the lateral viscosity variations, especially in the upper mantle, must be considered in the determination of long-term polar wander, since the variations in the delta I(sub xz) and delta I(sub yz) terms are directly responsible for exciting rotational movements.

Reducing tobacco use and access through strengthened minimum price laws.

PubMed

McLaughlin, Ian; Pearson, Anne; Laird-Metke, Elisa; Ribisl, Kurt

2014-10-01

Higher prices reduce consumption and initiation of tobacco products. A minimum price law that establishes a high statutory minimum price and prohibits the industry's discounting tactics for tobacco products is a promising pricing strategy as an alternative to excise tax increases. Although some states have adopted minimum price laws on the basis of statutorily defined price "markups" over the invoice price, existing state laws have been largely ineffective at increasing the retail price. We analyzed 3 new variations of minimum price laws that hold great potential for raising tobacco prices and reducing consumption: (1) a flat rate minimum price law similar to a recent enactment in New York City, (2) an enhanced markup law, and (3) a law that incorporates both elements.

Impacts of shallow geothermal energy production on redox processes and microbial communities.

PubMed

Bonte, Matthijs; Röling, Wilfred F M; Zaura, Egija; van der Wielen, Paul W J J; Stuyfzand, Pieter J; van Breukelen, Boris M

2013-12-17

Shallow geothermal systems are increasingly being used to store or harvest thermal energy for heating or cooling purposes. This technology causes temperature perturbations exceeding the natural variations in aquifers, which may impact groundwater quality. Here, we report the results of laboratory experiments on the effect of temperature variations (5-80 °C) on redox processes and associated microbial communities in anoxic unconsolidated subsurface sediments. Both hydrochemical and microbiological data showed that a temperature increase from 11 °C (in situ) to 25 °C caused a shift from iron-reducing to sulfate-reducing and methanogenic conditions. Bioenergetic calculations could explain this shift. A further temperature increase (>45 °C) resulted in the emergence of a thermophilic microbial community specialized in fermentation and sulfate reduction. Two distinct maxima in sulfate reduction rates, of similar orders of magnitude (5 × 10(-10) M s(-1)), were observed at 40 and 70 °C. Thermophilic sulfate reduction, however, had a higher activation energy (100-160 kJ mol(-1)) than mesophilic sulfate reduction (30-60 kJ mol(-1)), which might be due to a trade-off between enzyme stability and activity with thermostable enzymes being less efficient catalysts that require higher activation energies. These results reveal that while sulfate-reducing functionality can withstand a substantial temperature rise, other key biochemical processes appear more temperature sensitive.

Effect of air gap variation on the performance of single stator single rotor axial flux permanent magnet generator

NASA Astrophysics Data System (ADS)

Kasim, Muhammad; Irasari, Pudji; Hikmawan, M. Fathul; Widiyanto, Puji; Wirtayasa, Ketut

2017-02-01

The axial flux permanent magnet generator (AFPMG) has been widely used especially for electricity generation. The effect of the air gap variation on the characteristic and performances of single rotor - single stator AFPMG has been described in this paper. Effect of air gap length on the magnetic flux distribution, starting torque and MMF has been investigated. The two dimensional finite element magnetic method has been deployed to model and simulated the characteristics of the machine which is based on the Maxwell equation. The analysis has been done for two different air gap lengths which were 2 mm and 4 mm using 2D FEMM 4.2 software at no load condition. The increasing of air gap length reduces the air-gap flux density. For air gap 2 mm, the maximum value of the flux density was 1.04 T while 0.73 T occured for air gap 4 mm.. Based on the experiment result, the increasing air gap also reduced the starting torque of the machine with 39.2 Nm for air gap 2 mm and this value decreased into 34.2 Nm when the air gap increased to 4 mm. Meanwhile, the MMF that was generated by AFPMG decreased around 22% at 50 Hz due to the reduction of magnetic flux induced on stator windings. Overall, the research result showed that the variation of air gap has significant effect on the machine characteristics.

Flight Measurements to Determine Effect of a Spring-Loaded Tab on Longitudinal Stability of an Airplane

NASA Technical Reports Server (NTRS)

Hunter, Paul A.; Reeder, John P.

1946-01-01

In conjunction with a program of research on the general problem of stability of airplanes in the climbing condition, tests have been made of a spring-loaded tb which. is referred to as a ?springy tab,? installed on the elevator of a low-wing scout bomber. The tab was arranged to deflect upward with decrease in speed which caused an increase in the pull force required to trim at low speeds and thereby increased the stick-free static longitudinal stability of the airplane. It was found that the springy tab would increase the stick-free stability in all flight conditions, would reduce the danger of inadvertent stalling because of the definite pull force required to stall the airplane with power on, would reduce the effect of center-of-gravity position on stick-free static stability, and would have little effect on the elevator stick forces in accelerated f11ght. Another advantage of the springy tab is that it might be used to provide almost any desired variation of elevator stick force with speed by adjusting the tab hinge-moment characteristics and the variation of spring moment with tab deflection. Unlike the bungee and the bobweight, the springy tab would provide stick-free static stability without requiring a pull force to hold the stick back while taxying. A device similar to the springy tab may be used on the rudder or ailerons to eliminate undesirable trim-force variations with speed.

Performance of hospitals according to the ESC ACCA quality indicators and 30-day mortality for acute myocardial infarction: national cohort study using the United Kingdom Myocardial Ischaemia National Audit Project (MINAP) register.

PubMed

Bebb, Owen; Hall, Marlous; Fox, Keith A A; Dondo, Tatendashe B; Timmis, Adam; Bueno, Hector; Schiele, François; Gale, Chris P

2017-04-01

To investigate the application of the European Society of Cardiology Acute Cardiovascular Care Association quality indicators (QI) for acute myocardial infarction for the study of hospital performance and 30-day mortality. National cohort study (n = 118,075 patients, n = 211 hospitals, MINAP registry), 2012-13. Overall, 16 of the 20 QIs could be calculated. Eleven QIs had a significant inverse association with GRACE risk adjusted 30-day mortality (all P < 0.005). The association with the greatest magnitude was high attainment of the composite opportunity-based QI (80-100%) vs. zero attainment (odds ratio 0.04, 95% confidence interval 0.04-0.05, P < 0.001), increasing attainment from low (0.42, 0.37- 0.49, P < 0.001) to intermediate (0.15, 0.13-0.16, P < 0.001) was significantly associated with a reduced risk of 30-day mortality. A 1% increase in attainment of this QI was associated with a 3% reduction in 30-day mortality (0.97, 0.97-0.97, P < 0.001). The QI with the widest hospital variation was 'fondaparinux received among NSTEMI' (interquartile range 84.7%) and least variation 'centre organisation' (0.0%), with seven QIs depicting minimal variation (<11%). GRACE risk score adjusted 30-day mortality varied by hospital (median 6.7%, interquartile range 5.4-7.9%). Eleven QIs were significantly inversely associated with 30-day mortality. Increasing patient attainment of the composite quality indicator was the most powerful predictor; a 1% increase in attainment represented a 3% decrease in 30-day standardised mortality. The ESC QIs for acute myocardial infarction are applicable in a large health system and have the potential to improve care and reduce unwarranted variation in death from acute myocardial infarction. © The Author 2017. Published on behalf of the European Society of Cardiology

Performance of hospitals according to the ESC ACCA quality indicators and 30-day mortality for acute myocardial infarction: national cohort study using the United Kingdom Myocardial Ischaemia National Audit Project (MINAP) register

PubMed Central

Bebb, Owen; Hall, Marlous; Fox, Keith A. A.; Dondo, Tatendashe B.; Timmis, Adam; Bueno, Hector; Schiele, François; Gale, Chris P.

2017-01-01

Aims To investigate the application of the European Society of Cardiology Acute Cardiovascular Care Association quality indicators (QI) for acute myocardial infarction for the study of hospital performance and 30-day mortality. Methods and results National cohort study (n = 118,075 patients, n = 211 hospitals, MINAP registry), 2012-13. Overall, 16 of the 20 QIs could be calculated. Eleven QIs had a significant inverse association with GRACE risk adjusted 30-day mortality (all P < 0.005). The association with the greatest magnitude was high attainment of the composite opportunity-based QI (80-100%) vs. zero attainment (odds ratio 0.04, 95% confidence interval 0.04-0.05, P < 0.001), increasing attainment from low (0.42, 0.37- 0.49, P < 0.001) to intermediate (0.15, 0.13-0.16, P < 0.001) was significantly associated with a reduced risk of 30-day mortality. A 1% increase in attainment of this QI was associated with a 3% reduction in 30-day mortality (0.97, 0.97-0.97, P < 0.001). The QI with the widest hospital variation was ′fondaparinux received among NSTEMI′ (interquartile range 84.7%) and least variation ′centre organisation′ (0.0%), with seven QIs depicting minimal variation (<11%). GRACE risk score adjusted 30-day mortality varied by hospital (median 6.7%, interquartile range 5.4-7.9%). Conclusions Eleven QIs were significantly inversely associated with 30-day mortality. Increasing patient attainment of the composite quality indicator was the most powerful predictor; a 1% increase in attainment represented a 3% decrease in 30-day standardised mortality. The ESC QIs for acute myocardial infarction are applicable in a large health system and have the potential to improve care and reduce unwarranted variation in death from acute myocardial infarction. PMID:28329279

On the Regulation of the Pacific Warm Pool Temperature

NASA Technical Reports Server (NTRS)

Chou, Ming-Dah; Chou, Sue-Hsien; Chan, Pui-King; Lau, William K. M. (Technical Monitor)

2002-01-01

In the tropical western Pacific, regions of the highest sea surface temperature (SST) and the largest cloud cover are found to have the largest surface heating, primarily due to the weak evaporative cooling associated with weak winds. This situation is in variance with the suggestions that the temperature in the Pacific warm pool is regulated either by the reduced solar heating due to an enhanced cloudiness or by the enhanced evaporative cooling due to an elevated SST. It is clear that an enhanced surface heating in an enhanced convection region is not sustainable and must be interrupted by variations in large-scale atmospheric circulation. As the deep convective regions shift away from regions of high SST due primarily to seasonal variation and secondarily to interannual variation of the large-scale atmospheric and oceanic circulation, both trade wind and evaporative cooling in the high SST region increase, leading to a reduction in SST. We conclude that the evaporative cooling associated with the seasonal and interannual variations of trade winds in the primary factor that prevent the warm pool SST from increasing to a value much higher than what is observed.

Increasing crop diversity mitigates weather variations and improves yield stability.

PubMed

Gaudin, Amélie C M; Tolhurst, Tor N; Ker, Alan P; Janovicek, Ken; Tortora, Cristina; Martin, Ralph C; Deen, William

2015-01-01

Cropping sequence diversification provides a systems approach to reduce yield variations and improve resilience to multiple environmental stresses. Yield advantages of more diverse crop rotations and their synergistic effects with reduced tillage are well documented, but few studies have quantified the impact of these management practices on yields and their stability when soil moisture is limiting or in excess. Using yield and weather data obtained from a 31-year long term rotation and tillage trial in Ontario, we tested whether crop rotation diversity is associated with greater yield stability when abnormal weather conditions occur. We used parametric and non-parametric approaches to quantify the impact of rotation diversity (monocrop, 2-crops, 3-crops without or with one or two legume cover crops) and tillage (conventional or reduced tillage) on yield probabilities and the benefits of crop diversity under different soil moisture and temperature scenarios. Although the magnitude of rotation benefits varied with crops, weather patterns and tillage, yield stability significantly increased when corn and soybean were integrated into more diverse rotations. Introducing small grains into short corn-soybean rotation was enough to provide substantial benefits on long-term soybean yields and their stability while the effects on corn were mostly associated with the temporal niche provided by small grains for underseeded red clover or alfalfa. Crop diversification strategies increased the probability of harnessing favorable growing conditions while decreasing the risk of crop failure. In hot and dry years, diversification of corn-soybean rotations and reduced tillage increased yield by 7% and 22% for corn and soybean respectively. Given the additional advantages associated with cropping system diversification, such a strategy provides a more comprehensive approach to lowering yield variability and improving the resilience of cropping systems to multiple environmental stresses. This could help to sustain future yield levels in challenging production environments.

Leucine acts in the brain to suppress food intake but does not function as a physiological signal of low dietary protein

PubMed Central

Laeger, Thomas; Reed, Scott D.; Henagan, Tara M.; Fernandez, Denise H.; Taghavi, Marzieh; Addington, Adele; Münzberg, Heike; Martin, Roy J.; Hutson, Susan M.

2014-01-01

Intracerebroventricular injections of leucine are sufficient to suppress food intake, but it remains unclear whether brain leucine signaling represents a physiological signal of protein balance. We tested whether variations in dietary and circulating levels of leucine, or all three branched-chain amino acids (BCAAs), contribute to the detection of reduced dietary protein. Of the essential amino acids (EAAs) tested, only intracerebroventricular injection of leucine (10 μg) was sufficient to suppress food intake. Isocaloric low- (9% protein energy; LP) or normal- (18% protein energy) protein diets induced a divergence in food intake, with an increased consumption of LP beginning on day 2 and persisting throughout the study (P < 0.05). Circulating BCAA levels were reduced the day after LP diet exposure, but levels subsequently increased and normalized by day 4, despite persistent hyperphagia. Brain BCAA levels as measured by microdialysis on day 2 of diet exposure were reduced in LP rats, but this effect was most prominent postprandially. Despite these diet-induced changes in BCAA levels, reducing dietary leucine or total BCAAs independently from total protein was neither necessary nor sufficient to induce hyperphagia, while chronic infusion of EAAs into the brain of LP rats failed to consistently block LP-induced hyperphagia. Collectively, these data suggest that circulating BCAAs are transiently reduced by dietary protein restriction, but variations in dietary or brain BCAAs alone do not explain the hyperphagia induced by a low-protein diet. PMID:24898843

Reducing sugar production of sweet sorghum bagasse kraft pulp

NASA Astrophysics Data System (ADS)

Solihat, Nissa Nurfajrin; Fajriutami, Triyani; Adi, Deddy Triyono Nugroho; Fatriasari, Widya; Hermiati, Euis

2017-01-01

Kraft pulping of sweet sorghum bagasse (SSB) has been used for effective delignification method for cellulose production. This study was conducted to evaluate the performance pulp kraft of SSB for reducing sugar production. The study intended to investigate the effect of active alkali and sulfidity loading variation of SSB pulp kraft on reducing sugar yield per biomass. The SSB pulp was prepared after pulping using three variations of active alkali (17, 19, and 22%) and sulfidity loading (20, 22, and 24%) at 170°C for 4 h with liquor to wood ratio of 10. A total of 9 pulps were obtained from these pretreatments. Delignification pretreatment has been succesfully removed lignin and hemicellulose more than 90% and 50%, respectively. Increasing active alkali and sulfidity loading has significantly increased lignin removal caused by disruption of the cell wall structure for releasing lignin into black liquor in the cellulose extraction. The enzymatic hydrolysis of pulp was carried out with cellulase loading of 40 FPU per g substrate in the shaking incubator at 50°C and 150 rpm for 78 h. For each 24 h, the reducing sugar yield (DNS assay) has been observed. Even though the lignin and hemicellulose loss occurred along with higher active alkali loading, this condition tends to decrease its yield. The reducing sugar concentration varied between 7-8 g/L. Increasing active alkali and sulfidity was significantly decreased the reducing sugar per biomass. Pulp delignified by 17% active alkali and 20% sulfidity has demonstrated the maximum reducing sugar yield per biomass of 45.57% resulted after 72 h enzymatic hydrolysis. These results indicated that kraft pulping was success to degrade more lignin and hemicellulose content to facilitate the enzyme for breaking down the cellulose into its sugar monomer. A high loss of lignin and hemicellulose are not single factor to improve digestibility of SSB. This sugar has potential for yeast fermented into bioethanol.

Variation of Farmer Stock Grade Factors in Semi-Drying Trailers

USDA-ARS?s Scientific Manuscript database

Peanuts are increasingly being loaded into flat bottom semi-drying trailers in the field and transported to peanut buying points for curing, grading, and marketing. Conveyances in excess of 15 t are probed 15 times using the pneumatic sampler requiring considerable time for probing and reducing the...

Evolution of interleukin-1 receptor-like 1 and its role in rainbow trout (Oncorhynchus mykiss) resistance to Flavobacterium psychrophilum

USDA-ARS?s Scientific Manuscript database

Rainbow trout exhibit extensive phenotypic variation in innate disease resistance and we have divergently selected lines with either increased or reduced survival following exposure to the gram-negative bacterium, Flavobacterium psychrophilum (Fp). Following five generations of selection, gene expr...

Variations on standard broiler processing in an effort to reduce Campylobacter numbers on postpick carcasses

USDA-ARS?s Scientific Manuscript database

Campylobacter numbers increase on broiler carcasses during defeathering due to leakage of gut contents through the vent. We tested several processing modifications designed to interfere with the transfer of Campylobacter from gut contents to carcass surface. Numbers of Campylobacter detected on br...

Accounting for regional variation in both natural environment and human disturbance to improve performance of multimetric indices of lotic benthic diatoms.

PubMed

Tang, Tao; Stevenson, R Jan; Infante, Dana M

2016-10-15

Regional variation in both natural environment and human disturbance can influence performance of ecological assessments. In this study we calculated 5 types of benthic diatom multimetric indices (MMIs) with 3 different approaches to account for variation in ecological assessments. We used: site groups defined by ecoregions or diatom typologies; the same or different sets of metrics among site groups; and unmodeled or modeled MMIs, where models accounted for natural variation in metrics within site groups by calculating an expected reference condition for each metric and each site. We used data from the USEPA's National Rivers and Streams Assessment to calculate the MMIs and evaluate changes in MMI performance. MMI performance was evaluated with indices of precision, bias, responsiveness, sensitivity and relevancy which were respectively measured as MMI variation among reference sites, effects of natural variables on MMIs, difference between MMIs at reference and highly disturbed sites, percent of highly disturbed sites properly classified, and relation of MMIs to human disturbance and stressors. All 5 types of MMIs showed considerable discrimination ability. Using different metrics among ecoregions sometimes reduced precision, but it consistently increased responsiveness, sensitivity, and relevancy. Site specific metric modeling reduced bias and increased responsiveness. Combined use of different metrics among site groups and site specific modeling significantly improved MMI performance irrespective of site grouping approach. Compared to ecoregion site classification, grouping sites based on diatom typologies improved precision, but did not improve overall performance of MMIs if we accounted for natural variation in metrics with site specific models. We conclude that using different metrics among ecoregions and site specific metric modeling improve MMI performance, particularly when used together. Applications of these MMI approaches in ecological assessments introduced a tradeoff with assessment consistency when metrics differed across site groups, but they justified the convenient and consistent use of ecoregions. Copyright © 2016 Elsevier B.V. All rights reserved.

Future initiatives to reduce lung cancer incidence in the United Kingdom: smoking cessation, radon remediation and the impact of social change.

PubMed

Denman, Antony R; Rogers, Stephen; Timson, Karen; Phillips, Paul S; Crockett, Robin Gm; Groves-Kirkby, Christopher J

2015-03-01

Smoking and radon cause lung cancer, with smoking being the more significant risk factor. Although programmes to identify UK houses with raised radon levels and to encourage remedial action started in 1990, uptake has been limited and those most at risk, smokers and young families, are not being reached. The risks from smoking and radon are multiplicative. Public health campaigns have reduced smoking prevalence significantly. Since most radon-induced lung cancers occur in smokers, reducing the number of smokers will reduce the number of radon-induced lung cancers. This article considers the impact of reducing smoking prevalence on the effectiveness of radon remediation programmes, combining this with demographic trends and regional variations to assess implications for future public health. Results on cost-effectiveness of smoking cessation and radon remediation programmes were combined with government figures for smoking prevalence to estimate the number of cancers averted and the cost-effectiveness of such programmes, taking into account demographic changes, including increasing life expectancy. Regional variations in smoking prevalence and smoking cessation programmes were reviewed, comparing these to the geographic variation of radon. The continuing impact of smoking cessation programmes in reducing smoking prevalence will reduce the number of radon-induced lung cancers, but with a lag. Smoking cessation programmes are more cost-effective than radon remediation programmes, presenting an additional opportunity to reduce radon risk to smokers. Regional data show no correlation between smoking prevalence and radon levels. Reduced smoking prevalence reduces the effectiveness of radon remediation programmes. This, coupled with limited uptake of radon remediation, suggests that radon remediation programmes should be targeted, and that an integrated public health policy for smoking and radon is appropriate. Lack of correlation between smoking prevalence and radon suggests that local assessment of relative priorities for public health strategies, such as the 'Total Place' initiative, is appropriate. © Royal Society for Public Health 2014.

Molecular Modeling of the Structural and Dynamical Changes in Calcium Channel TRPV5 Induced by the African-Specific A563T Variation.

PubMed

Wang, Lingyun; Holmes, Ross P; Peng, Ji-Bin

2016-03-01

Transient receptor potential cation channels, vanilloid subfamily, member 5 (TRPV5) plays a key role in active Ca(2+) reabsorption in the kidney. Variations in TRPV5 occur at high frequency in African populations and may contribute to their higher efficiency of Ca(2+) reabsorption. One of the African specific variations, A563T, exhibits increased Ca(2+) transport ability. However, it is unclear how this variation influences the channel pore. On the basis of the structure of TRPV1, a TRPV5 model was generated to simulate the structural and dynamical changes induced by the A563T variation. On the basis of this model, amino acid residue 563 interacts with V540, which is one residue away from the key residue, D542, involved in Ca(2+) selectivity and Mg(2+) blockade. The A563T variation increases secondary structure stability and reduces dynamical motion of D542. In addition, the A563T variation alters the electrostatic potential of the outer surface of the pore. Differences in contact between selective filter residues and residue 563 and in electrostatic potential between the two TRPV5 variants were also observed in another model derived from an alternative alignment in the selective filters between TRPV5 and TRPV1. These findings indicate that the A563T variation induces structural, dynamical, and electrostatic changes in the TRPV5 pore, providing structural insight into the functional alterations associated with the A563T variation.

Legume species differ in the responses of their functional traits to plant diversity.

PubMed

Roscher, Christiane; Schmid, Bernhard; Buchmann, Nina; Weigelt, Alexandra; Schulze, Ernst-Detlef

2011-02-01

Plants can respond to environmental impacts by variation in functional traits, thereby increasing their performance relative to neighbors. We hypothesized that trait adjustment should also occur in response to influences of the biotic environment, in particular different plant diversity of the community. We used 12 legume species as a model and assessed their variation in morphological, physiological, life-history and performance traits in experimental grasslands of different plant species (1, 2, 4, 8, 16 and 60) and functional group (1-4) numbers. Mean trait values and their variation in response to plant diversity varied among legume species and from trait to trait. The tall-growing Onobrychis viciifolia showed little trait variation in response to increasing plant diversity, whereas the species with shorter statures responded in apparently adaptive ways. The formation of longer shoots with elongated internodes, increased biomass allocation to supporting tissue at the cost of leaf mass, reduced branching, higher specific leaf areas and lower foliar δ(13)C values indicated increasing efforts for light acquisition in more diverse communities. Although leaf nitrogen concentrations and shoot biomass:nitrogen ratios were not affected by increasing plant diversity, foliar δ(15)N values of most legumes decreased and the application of the (15)N natural abundance method suggested that they became more reliant on symbiotic N(2) fixation. Some species formed fewer inflorescences and delayed flowering with increasing community diversity. The observed variation in functional traits generally indicated strategies of legumes to optimize light and nutrient capturing, but they were largely species-dependent and only partly attributable to increasing canopy height and community biomass with increasing plant diversity. Thus, the analysis of individual plant species and their adjustment to growth conditions in communities of increasing plant diversity is essential to get a deeper insight into the mechanisms behind biodiversity-ecosystem functioning relationships.

Morphological and physiological changes during reproduction and their relationships to reproductive performance in a capital breeder.

PubMed

Stahlschmidt, Zachary R; Lourdais, Olivier; Lorioux, Sophie; Butler, Michael W; Davis, Jon R; Salin, Karine; Voituron, Yann; DeNardo, Dale F

2013-01-01

Current reproductive effort typically comes at a cost to future reproductive value by altering somatic function (e.g., growth or self-maintenance). Furthermore, effects of reproduction often depend on both fecundity and stage of reproduction, wherein allocation of resources into additional offspring and/or stages of reproduction results in increased costs. Despite these widely accepted generalities, interindividual variation in the effects of reproduction is common-yet the proximate basis that allows some individuals to mitigate these detrimental effects is unclear. We serially measured several variables of morphology (e.g., musculature) and physiology (e.g., antioxidant defenses) in female Children's pythons (Antaresia childreni) throughout reproduction to examine how these traits change over the course of reproduction and whether certain physiological traits are associated with reduced effects of reproduction in some individuals. Reproduction in this capital breeder was associated with changes in both morphology and physiology, but only morphological changes varied with fecundity and among specific reproductive stages. During reproduction, we detected negative relationships between morphology and self-maintenance (e.g., increased muscle allocation to reproduction was related to reduced immune function). Additionally, females that allocated resources more heavily into current reproduction also did so during future reproduction, and these females assimilated resources more efficiently, experienced reduced detriments to self-maintenance (e.g., lower levels of oxidative damage and glucocorticoids) during reproduction, and produced clutches with greater hatching success. Our results suggest that interindividual variation in specific aspects of physiology (assimilation efficiency and oxidative status) may drive variation in reproductive performance.

Genomic Variation in Natural Populations of Drosophila melanogaster

PubMed Central

Langley, Charles H.; Stevens, Kristian; Cardeno, Charis; Lee, Yuh Chwen G.; Schrider, Daniel R.; Pool, John E.; Langley, Sasha A.; Suarez, Charlyn; Corbett-Detig, Russell B.; Kolaczkowski, Bryan; Fang, Shu; Nista, Phillip M.; Holloway, Alisha K.; Kern, Andrew D.; Dewey, Colin N.; Song, Yun S.; Hahn, Matthew W.; Begun, David J.

2012-01-01

This report of independent genome sequences of two natural populations of Drosophila melanogaster (37 from North America and 6 from Africa) provides unique insight into forces shaping genomic polymorphism and divergence. Evidence of interactions between natural selection and genetic linkage is abundant not only in centromere- and telomere-proximal regions, but also throughout the euchromatic arms. Linkage disequilibrium, which decays within 1 kbp, exhibits a strong bias toward coupling of the more frequent alleles and provides a high-resolution map of recombination rate. The juxtaposition of population genetics statistics in small genomic windows with gene structures and chromatin states yields a rich, high-resolution annotation, including the following: (1) 5′- and 3′-UTRs are enriched for regions of reduced polymorphism relative to lineage-specific divergence; (2) exons overlap with windows of excess relative polymorphism; (3) epigenetic marks associated with active transcription initiation sites overlap with regions of reduced relative polymorphism and relatively reduced estimates of the rate of recombination; (4) the rate of adaptive nonsynonymous fixation increases with the rate of crossing over per base pair; and (5) both duplications and deletions are enriched near origins of replication and their density correlates negatively with the rate of crossing over. Available demographic models of X and autosome descent cannot account for the increased divergence on the X and loss of diversity associated with the out-of-Africa migration. Comparison of the variation among these genomes to variation among genomes from D. simulans suggests that many targets of directional selection are shared between these species. PMID:22673804

FORAGES AND PASTURES SYMPOSIUM: Improving soil health and productivity on grasslands using managed grazing of livestock.

PubMed

Russell, J R; Bisinger, J J

2015-06-01

Beyond grazing, managed grasslands provide ecological services that may offer economic incentives for multifunctional use. Increasing biodiversity of plant communities may maximize net primary production by optimizing utilization of available light, water, and nutrient resources; enhance production stability in response to climatic stress; reduce invasion of exotic species; increase soil OM; reduce nutrient leaching or loading in surface runoff; and provide wildlife habitat. Strategically managed grazing may increase biodiversity of cool-season pastures by creating disturbance in plant communities through herbivory, treading, nutrient cycling, and plant seed dispersal. Soil OM will increase carbon and nutrient sequestration and water-holding capacity of soils and is greater in grazed pastures than nongrazed grasslands or land used for row crop or hay production. However, results of studies evaluating the effects of different grazing management systems on soil OM are limited and inconsistent. Although roots and organic residues of pasture forages create soil macropores that reduce soil compaction, grazing has increased soil bulk density or penetration resistance regardless of stocking rates or systems. But the effects of the duration of grazing and rest periods on soil compaction need further evaluation. Because vegetative cover dissipates the energy of falling raindrops and plant stems and tillers reduce the rate of surface water flow, managing grazing to maintain adequate vegetative cover will minimize the effects of treading on water infiltration in both upland and riparian locations. Through increased diversity of the plant community with alterations of habitat structure, grazing systems can be developed that enhance habitat for wildlife and insect pollinators. Although grazing management may enhance the ecological services provided by grasslands, environmental responses are controlled by variations in climate, soil, landscape position, and plant community resulting in considerable spatial and temporal variation in the responses. Furthermore, a single grazing management system may not maximize livestock productivity and each of the potential ecological services provided by grasslands. Therefore, production and ecological goals must be integrated to identify the optimal grazing management system.

Compensatory mechanisms in Great Lakes sea lamprey populations: implications for alternative control strategies

USGS Publications Warehouse

Jones, Michael L.; Bergstedt, R.A.; Twohey, Michael B.; Fodale, Michael F.; Cuddy, Douglas W.; Slade, Jeffrey W.

2003-01-01

Compensatory mechanisms are demographic processes that tend to increase population growth rates at lower population density. These processes will tend to reduce the effectiveness of actions that use controls on reproductive success to suppress sea lamprey (Petromyzon marinus), an economically important pest in the Great Lakes. Historical evidence for compensatory mechanisms in sea lamprey populations was reviewed, and revealed: (1) strong evidence for shifts in sex ratios as sea lamprey abundance was reduced in the early years of the control program; (2) weak and equivocal evidence for increased growth rates of sea lamprey cohorts re-colonizing streams following a lampricide treatment; and (3) suggestions of other compensatory processes, such as earlier ages at metamorphosis, but with little empirical evidence. Larval size distribution data for cohorts in the first and second years following a lampricide treatment (26 pairs of cohorts in 20 streams) was analyzed and did not indicate a consistent pattern of more rapid growth of the first colonizing cohort (only 11 of 33 cases). To test for compensation between spawning and age-1 in sea lamprey populations, data were analyzed for 49 stream-years for which spawning female abundance was known and age-1 abundance was estimated in the following year. A fit of these data to a Ricker stock-recruitment function showed evidence for compensation, measured as reduced survival to age 1 at higher abundance of spawning females. More obvious, however, was a large amount of density-independent variation in survival, which tends to mask evidence for compensatory survival. The results were applied to a simple model that simulates sea lamprey populations and their control in a hypothetical lake. Control strategies that targeted reproductive success performed far less well than comparable strategies that targeted larval populations, because density-independent recruitment variation leads to occasional strong year classes even when spawner abundance is reduced to low levels through alternative control. It is concluded that further study of recruitment variation in lamprey populations is critical to rationalizing alternative controls that target reproductive success, and that recruitment variation needs to be incorporated into models used to evaluate sea lamprey control options.

Predicting evolutionary rescue via evolving plasticity in stochastic environments

PubMed Central

Baskett, Marissa L.

2016-01-01

Phenotypic plasticity and its evolution may help evolutionary rescue in a novel and stressful environment, especially if environmental novelty reveals cryptic genetic variation that enables the evolution of increased plasticity. However, the environmental stochasticity ubiquitous in natural systems may alter these predictions, because high plasticity may amplify phenotype–environment mismatches. Although previous studies have highlighted this potential detrimental effect of plasticity in stochastic environments, they have not investigated how it affects extinction risk in the context of evolutionary rescue and with evolving plasticity. We investigate this question here by integrating stochastic demography with quantitative genetic theory in a model with simultaneous change in the mean and predictability (temporal autocorrelation) of the environment. We develop an approximate prediction of long-term persistence under the new pattern of environmental fluctuations, and compare it with numerical simulations for short- and long-term extinction risk. We find that reduced predictability increases extinction risk and reduces persistence because it increases stochastic load during rescue. This understanding of how stochastic demography, phenotypic plasticity, and evolution interact when evolution acts on cryptic genetic variation revealed in a novel environment can inform expectations for invasions, extinctions, or the emergence of chemical resistance in pests. PMID:27655762

Development of flow separation control system to reduce the vibration of wind turbine blades

NASA Astrophysics Data System (ADS)

Kim, Ho-Young; Kim, Ho-Hyun; Han, Jong-Seob; Han, Jae-Hung

2017-04-01

The size of wind turbine blade has been continuously increased. Large-scale wind turbine blades induce loud noise, vibration; and maintenance difficulty is also increased. It causes the eventual increases of the cost of energy. The vibration of wind turbine blade is caused by several reasons such as a blade rotation, tower shadow, wind shear, and flow separation of a wind turbine blade. This wind speed variation changes in local angle of attack of the blades and create the vibration. The variation of local angle of attack influences the lift coefficient and causes the large change of the lift. In this study, we focus on the lift coefficient control using a flow control device to reduce the vibration. DU35-A15 airfoil was employed as baseline model. A plasma actuator was installed to generate the upwind jet in order to control the lift coefficient. Wind tunnel experiment was performed to demonstrate of the performance of the plasma actuator. The results show the plasma actuator can induce the flow separation compared with the baseline model. In addition, the actuator can delay the flow separation depending on the input AC frequency with the same actuator configuration.

Repeat prostate-specific antigen (PSA) test before prostate biopsy: a 20% decrease in PSA values is associated with a reduced risk of cancer and particularly of high-grade cancer.

PubMed

De Nunzio, Cosimo; Lombardo, Riccardo; Nacchia, Antonio; Tema, Giorgia; Tubaro, Andrea

2018-07-01

To analyse the impact of repeating a prostate-specific antigen (PSA) level assessment on prostate biopsy decision in a cohort of men undergoing prostate biopsy. From 2015 onwards, we consecutively enrolled, at a single institution in Italy, men undergoing 12-core transrectal ultrasonography-guided prostate needle biopsy. Indication for prostate biopsy was a PSA level of ≥4 ng/mL. Demographic, clinical, and histopathological data were collected. The PSA level was tested at enrolment (PSA 1 ) and 4 weeks later on the day before biopsy (PSA 2 ). Variations in PSA level were defined as: stable PSA 2 within a 10% variation, stable PSA 2 within a 20% variation, PSA 2 decreased by ≥10%, PSA 2 decreased by ≥20%, PSA 2 increased by ≥10%, PSA 2 increased by ≥20%, and PSA 2 <4 ng/mL. Percentages and multinomial logistic regression were used to analyse biopsy outcomes. High-grade cancer was defined as Grade group ≥3. Overall, 331 patients were enrolled. Prostate cancer was diagnosed in 153/331 (46%) patients and of them 80/153 (52%) had high-grade disease. When compared to the rest of the population, patients with a stable PSA within 20% variation had a higher risk of prostate cancer (odds ratio [OR] 1.80, P < 0.05) and high grade disease (OR 2.56, P < 0.05), patients with a PSA2 decreased by ≥20% had a lower risk of prostate cancer (OR 0.37, P < 0.05) and high grade disease (OR 0.13, P < 0.05), whilst patients with a PSA2 increased by ≥10% had an increased risk of high-grade prostate cancer (OR 1.93, P < 0.05). When PSA returned to normal values (<4 ng/mL) both risks of prostate cancer and high-grade disease were reduced (OR 0.33 and 0.01, respectively, P = 0.001). In a cohort of Italian men undergoing prostate biopsy, a reduction of ≥20% in PSA levels significantly reduced the risk of high-grade prostate cancer. Further multicentre studies should validate our present results. © 2018 The Authors BJU International © 2018 BJU International Published by John Wiley & Sons Ltd.

Reducing variation in a rabbit vaccine safety study with particular emphasis on housing conditions and handling.

PubMed

Verwer, Cynthia M; van der Ark, Arno; van Amerongen, Geert; van den Bos, Ruud; Hendriksen, Coenraad F M

2009-04-01

This paper describes the results of a study of the effects of modified housing conditions, conditioning and habituation on humans using a rabbit model for monitoring whole-cell pertussis vaccine (pWCV)-induced adverse effects. The study has been performed with reference to previous vaccine safety studies of pWCV in rabbits in which results were difficult to interpret due to the large variation in experimental outcome, especially in the key parameter deep-body temperature (T(b)). Certain stressful laboratory conditions, as well as procedures involving humans, e.g. blood sampling, inoculation and cage-cleaning, were hypothesized to cause this large variation. The results of this study show that under modified housing conditions rabbits have normal circadian body temperatures. This allowed discrimination of pWCV-induced adverse effects in which handled rabbits tended to show a dose-related increase in temperature after inoculation with little variance, whereas non-handled rabbits did not. Effects of experimental and routine procedures on body temperature were significantly reduced under modified conditions and were within the normal T(b) range. Handled animals reacted less strongly and with less variance to experimental procedures, such as blood sampling, injection and cage-cleaning, than non-handled rabbits. Overall, handling had a positive effect on the behaviour of the animals. Data show that the housing modifications have provided a more robust model for monitoring pWCV adverse effects. Furthermore, conditioning and habituation of rabbits to humans reduce the variation in experimental outcome, which might allow for a reduction in the number of animals used. In addition, this also reduces distress and thus contributes to refining this animal model.

[Effects of reduced solar radiation on winter wheat flag leaf net photosynthetic rate].

PubMed

Zheng, You-Fei; Ni, Yan-Li; Mai, Bo-Ru; Wu, Rong-Jun; Feng, Yan; Sun, Jian; Li, Jian; Xu, Jing-Xin

2011-06-01

Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors. Five treatments were installed, i. e., 15% (T15), 20% (T20) , 40% (T40), 60% (T60), and 100% (CK) of total incident solar radiation. Reduced solar irradiance increased the chlorophyll and lutein contents significantly, but decreased the net photosynthetic rate (Pn). Under different solar irradiance, the diurnal variation of Pn had greater difference, and the daily maximum Pn was in the order of CK > T60 > T40 > T 20 > T15. In CK, the Pn exhibited a double peak diurnal curve; while in the other four treatments, the Pn showed a single peak curve, and the peak was lagged behind that of CK. Correlation analysis showed that reduced solar irradiance was the main factor affecting the diurnal variation of Pn, but the physiological parameters also played important roles in determining the diurnal variation of Pn. In treatments T60 and T40, the photosynthesis active radiation (PAR), leaf temperature (T1) , stomatal conductance (Gs) , and transpiration rate (Tr) were significantly positively correlated with Pn, suggesting their positive effects on Pn. The intercellular CO2 concentration (Ci) and stomatal limitation (Ls) had significant negative correlations with Pn in treatments T60 and T40 but significant positive correlations with Pn in treatments T20 and T15, implying that the Ci and Ls had negative (or positive) effects on Pn when the solar irradiance was higher (or lower) than 40% of incident solar irradiance.

[Analysis of acid rain characteristics of Lin'an Regional Background Station using long-term observation data].

PubMed

Li, Zheng-Quan; Ma, Hao; Mao, Yu-Ding; Feng, Tao

2014-02-01

Using long-term observation data of acid rain at Lin'an Regional Background Station (Lin'an RBS), this paper studied the interannual and monthly variations of acid rain, the reasons for the variations, and the relationships between acid rain and meteorological factors. The results showed that interannual variation of acid rain at Lin'an RBS had a general increasing trend in which there were two obvious intensifying processes and two distinct weakening processes, during the period ranging from 1985 to 2012. In last two decades, the monthly variation of acid rain at Lin'an RBS indicated that rain acidity and frequency of severe acid rain were increasing but the frequency of weak acid rain was decreasing when moving towards bilateral side months of July. Acid rain occurrence was affected by rainfall intensity, wind speed and wind direction. High frequency of severe acid rain and low frequency of weak acid rain were on days with drizzle, but high frequency of weak acid rain and low frequency of severe acid rain occurred on rainstorm days. With wind speed upgrading, the frequency of acid rain and the proportion of severe acid rain were declining, the pH value of precipitation was reducing too. Another character is that daily dominant wind direction of weak acid rain majorly converged in S-W section ,however that of severe acid rain was more likely distributed in N-E section. The monthly variation of acid rain at Lin'an RBS was mainly attributed to precipitation variation, the increasing and decreasing of monthly incoming wind from SSE-WSW and NWN-ENE sections of wind direction. The interannual variation of acid rain could be due to the effects of energy consumption raising and significant green policies conducted in Zhejiang, Jiangsu and Shanghai.

Continuous-cyclic variations in the b-value of the earthquake frequency-magnitude distribution

NASA Astrophysics Data System (ADS)

El-Isa, Z. H.

2013-10-01

Seismicity of the Earth ( M ≥ 4.5) was compiled from NEIC, IRIS and ISC catalogues and used to compute b-value based on various time windows. It is found that continuous cyclic b-variations occur on both long and short time scales, the latter being of much higher value and sometimes in excess of 0.7 of the absolute b-value. These variations occur not only yearly or monthly, but also daily. Before the occurrence of large earthquakes, b-values start increasing with variable gradients that are affected by foreshocks. In some cases, the gradient is reduced to zero or to a negative value a few days before the earthquake occurrence. In general, calculated b-values attain maxima 1 day before large earthquakes and minima soon after their occurrence. Both linear regression and maximum likelihood methods give correlatable, but variable results. It is found that an expanding time window technique from a fixed starting point is more effective in the study of b-variations. The calculated b-variations for the whole Earth, its hemispheres, quadrants and the epicentral regions of some large earthquakes are of both local and regional character, which may indicate that in such cases, the geodynamic processes acting within a certain region have a much regional effect within the Earth. The b-variations have long been known to vary with a number of local and regional factors including tectonic stresses. The results reported here indicate that geotectonic stress remains the most significant factor that controls b-variations. It is found that for earthquakes with M w ≥ 7, an increase of about 0.20 in the b-value implies a stress increase that will result in an earthquake with a magnitude one unit higher.

Recognizing and Reducing Analytical Errors and Sources of Variation in Clinical Pathology Data in Safety Assessment Studies.

PubMed

Schultze, A E; Irizarry, A R

2017-02-01

Veterinary clinical pathologists are well positioned via education and training to assist in investigations of unexpected results or increased variation in clinical pathology data. Errors in testing and unexpected variability in clinical pathology data are sometimes referred to as "laboratory errors." These alterations may occur in the preanalytical, analytical, or postanalytical phases of studies. Most of the errors or variability in clinical pathology data occur in the preanalytical or postanalytical phases. True analytical errors occur within the laboratory and are usually the result of operator or instrument error. Analytical errors are often ≤10% of all errors in diagnostic testing, and the frequency of these types of errors has decreased in the last decade. Analytical errors and increased data variability may result from instrument malfunctions, inability to follow proper procedures, undetected failures in quality control, sample misidentification, and/or test interference. This article (1) illustrates several different types of analytical errors and situations within laboratories that may result in increased variability in data, (2) provides recommendations regarding prevention of testing errors and techniques to control variation, and (3) provides a list of references that describe and advise how to deal with increased data variability.

Active and hibernating turbulence in minimal channel flow of newtonian and polymeric fluids.

PubMed

Xi, Li; Graham, Michael D

2010-05-28

Turbulent channel flow of drag-reducing polymer solutions is simulated in minimal flow geometries. Even in the Newtonian limit, we find intervals of "hibernating" turbulence that display many features of the universal maximum drag reduction asymptote observed in polymer solutions: weak streamwise vortices, nearly nonexistent streamwise variations, and a mean velocity gradient that quantitatively matches experiments. As viscoelasticity increases, the frequency of these intervals also increases, while the intervals themselves are unchanged, leading to flows that increasingly resemble maximum drag reduction.

Diverging climate trends in Mongolian taiga forests influence growth and regeneration of Larix sibirica

PubMed Central

Dulamsuren, Choimaa; Khishigjargal, Mookhor; Leuschner, Hanns Hubert; Leuschner, Christoph

2010-01-01

Central and semiarid north-eastern Asia was subject to twentieth century warming far above the global average. Since forests of this region occur at their drought limit, they are particularly vulnerable to climate change. We studied the regional variations of temperature and precipitation trends and their effects on tree growth and forest regeneration in Mongolia. Tree-ring series from more than 2,300 trees of Siberian larch (Larix sibirica) collected in four regions of Mongolia’s forest zone were analyzed and related to available weather data. Climate trends underlie a remarkable regional variation leading to contrasting responses of tree growth in taiga forests even within the same mountain system. Within a distance of a few hundred kilometers (140–490 km), areas with recently reduced growth and regeneration of larch alternated with regions where these parameters remained constant or even increased. Reduced productivity could be correlated with increasing summer temperatures and decreasing precipitation; improved growth conditions were found at increasing precipitation, but constant summer temperatures. An effect of increasing winter temperatures on tree-ring width or forest regeneration was not detectable. Since declines of productivity and regeneration are more widespread in the Mongolian taiga than the opposite trend, a net loss of forests is likely to occur in the future, as strong increases in temperature and regionally differing changes in precipitation are predicted for the twenty-first century. PMID:20571829

Diverging climate trends in Mongolian taiga forests influence growth and regeneration of Larix sibirica.

PubMed

Dulamsuren, Choimaa; Hauck, Markus; Khishigjargal, Mookhor; Leuschner, Hanns Hubert; Leuschner, Christoph

2010-08-01

Central and semiarid north-eastern Asia was subject to twentieth century warming far above the global average. Since forests of this region occur at their drought limit, they are particularly vulnerable to climate change. We studied the regional variations of temperature and precipitation trends and their effects on tree growth and forest regeneration in Mongolia. Tree-ring series from more than 2,300 trees of Siberian larch (Larix sibirica) collected in four regions of Mongolia's forest zone were analyzed and related to available weather data. Climate trends underlie a remarkable regional variation leading to contrasting responses of tree growth in taiga forests even within the same mountain system. Within a distance of a few hundred kilometers (140-490 km), areas with recently reduced growth and regeneration of larch alternated with regions where these parameters remained constant or even increased. Reduced productivity could be correlated with increasing summer temperatures and decreasing precipitation; improved growth conditions were found at increasing precipitation, but constant summer temperatures. An effect of increasing winter temperatures on tree-ring width or forest regeneration was not detectable. Since declines of productivity and regeneration are more widespread in the Mongolian taiga than the opposite trend, a net loss of forests is likely to occur in the future, as strong increases in temperature and regionally differing changes in precipitation are predicted for the twenty-first century.

The mean and variability of a floral trait have opposing effects on fitness traits

PubMed Central

Dai, Can; Liang, Xijian; Ren, Jie; Liao, Minglin; Li, Jiyang; Galloway, Laura F.

2016-01-01

Background and Aims Floral traits are essential for ensuring successful pollination and reproduction in flowering plants. In particular, style and anther positions are key for pollination accuracy and efficiency. Variation in these traits among individuals has been well studied, but less is known about variation within flowers and plants and its effect on pollination and reproductive success. Methods Style deflexion is responsible for herkogamy and important for pollen deposition in Passiflora incarnata. The degree of deflexion may vary among stigmas within flowers as well as among flowers. We measured the variability of style deflexion at both the flower and the plant level. The fitness consequences of the mean and variation of style deflexion were then evaluated under natural pollination by determining their relationship to pollen deposition, seed production and average seed weight using structural equation modelling. In addition, the relationship between style deflexion and self-pollen deposition was estimated in a greenhouse experiment. Key Results We found greater variation in style deflexion within flowers and plants than among plants. Variation of style deflexion at the flower and plant level was positively correlated, suggesting that variability in style deflexion may be a distinct trait in P. incarnata. Lower deflexion and reduced variation in that deflexion increased pollen deposition, which in turn increased seed number. However, lower styles also increased self-pollen deposition. In contrast, higher deflexion and greater variability of that deflexion increased variation in pollen deposition, which resulted in heavier seeds. Conclusions Variability of style deflexion and therefore stigma placement, independent from the mean, appears to be a property of individual P. incarnata plants. The mean and variability of style deflexion in P. incarnata affected seed number and seed weight in contrasting ways, through the quantity and potentially quality of pollen deposition. This antagonistic selection via different fitness components may maintain diverse style phenotypes. PMID:26749589

An experimental approach of decoupling Seebeck coefficient and electrical resistivity

NASA Astrophysics Data System (ADS)

Muhammed Sabeer N., A.; Paulson, Anju; Pradyumnan, P. P.

2018-04-01

The Thermoelectrics (TE) has drawn increased attention among renewable energy technologies. The performance of a thermoelectric material is quantified by a dimensionless thermoelectric figure of merit, ZT=S2σT/κ, where S and σ vary inversely each other. Thus, improvement in ZT is not an easy task. So, researchers have been trying different parameter variations during thin film processing to improve TE properties. In this work, tin nitride (Sn3N4) thin films were deposited on glass substrates by reactive RF magnetron sputtering and investigated its thermoelectric response. To decouple the covariance nature of Seebeck coefficient and electrical resistivity for the enhancement of power factor (S2σ), the nitrogen gas pressure during sputtering was reduced. Reduction in nitrogen gas pressure reduced both sputtering pressure and amount of nitrogen available for reaction during sputtering. This experimental approach of combined effect introduced preferred orientation and stoichiometric variations simultaneously in the sputtered Sn3N4 thin films. The scattering mechanism associated with these variations enhanced TE properties by independently drive the Seebeck coefficient and electrical resistivity parameters.

Nonintrusive, multipoint velocity measurements in high-pressure combustion flows

NASA Technical Reports Server (NTRS)

Allen, M.; Davis, S.; Kessler, W.; Legner, H.; Mcmanus, K.; Mulhall, P.; Parker, T.; Sonnenfroh, D.

1993-01-01

A combined experimental and analytical effort was conducted to demonstrate the applicability of OH Doppler-shifted fluorescence imaging of velocity distributions in supersonic combustion gases. The experiments were conducted in the underexpanded exhaust flow from a 6.8 atm, 2400 K, H2-O2-N2 burner exhausting into the atmosphere. In order to quantify the effects of in-plane variations of the gas thermodynamic properties on the measurement accuracy, a set of detailed measurements of the OH (1,0) band collisional broadening and shifting in H2-air gases was produced. The effect of pulse-to-pulse variations in the dye laser bandshape was also examined in detail and a modification was developed which increased in the single pulse bandwidth, thereby increasing the intraimage velocity dynamic range as well as reducing the sensitivity of the velocity measurement to the gas property variations. Single point and imaging measurements of the velocity field in the exhaust flowfield were compared with 2D, finite-rate kinetics simulations of the flowfield. Relative velocity accuracies of +/- 50 m/s out of 1600 m/s were achieved in time-averaged imaging measurements of the flow over an order of magnitude variation in pressure and a factor of two variation in temperature.

Reducing Tobacco Use and Access Through Strengthened Minimum Price Laws

PubMed Central

Pearson, Anne; Laird-Metke, Elisa; Ribisl, Kurt

2014-01-01

Higher prices reduce consumption and initiation of tobacco products. A minimum price law that establishes a high statutory minimum price and prohibits the industry’s discounting tactics for tobacco products is a promising pricing strategy as an alternative to excise tax increases. Although some states have adopted minimum price laws on the basis of statutorily defined price “markups” over the invoice price, existing state laws have been largely ineffective at increasing the retail price. We analyzed 3 new variations of minimum price laws that hold great potential for raising tobacco prices and reducing consumption: (1) a flat rate minimum price law similar to a recent enactment in New York City, (2) an enhanced markup law, and (3) a law that incorporates both elements. PMID:25121820

Enhanced Performance of Streamline-Traced External-Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.

2015-01-01

A computational design study was conducted to enhance the aerodynamic performance of streamline-traced, external-compression inlets for Mach 1.6. Compared to traditional external-compression, two-dimensional and axisymmetric inlets, streamline-traced inlets promise reduced cowl wave drag and sonic boom, but at the expense of reduced total pressure recovery and increased total pressure distortion. The current study explored a new parent flowfield for the streamline tracing and several variations of inlet design factors, including the axial displacement and angle of the subsonic cowl lip, the vertical placement of the engine axis, and the use of porous bleed in the subsonic diffuser. The performance was enhanced over that of an earlier streamline-traced inlet such as to increase the total pressure recovery and reduce total pressure distortion.

The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length.

PubMed

Cook, Daniel E; Zdraljevic, Stefan; Tanny, Robyn E; Seo, Beomseok; Riccardi, David D; Noble, Luke M; Rockman, Matthew V; Alkema, Mark J; Braendle, Christian; Kammenga, Jan E; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C

2016-09-01

Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans. Copyright © 2016 by the Genetics Society of America.

Development of an automated procedure for estimation of the spatial variation of runoff in large river basins

USDA-ARS?s Scientific Manuscript database

The use of distributed parameter models to address water resource management problems has increased in recent years. Calibration is necessary to reduce the uncertainties associated with model input parameters. Manual calibration of a distributed parameter model is a very time consuming effort. There...

Evidence of counter-gradient growth in western pond turtles (Actinemys marmorata) across thermal gradients

Treesearch

Melissa L. Snover; Michael J. Adams; Donald T. Ashton; Jamie B. Bettaso; Hartwell H. Welsh

2015-01-01

Summary1. Counter-gradient growth, where growth per unit temperature increases as temperature decreases, can reduce the variation in ectothermic growth rates across environmental gradients. Understanding how ectothermic species respond to changing temperatures is essential to their conservation and management due to human-altered habitats and changing...

Increased Attention to Human Sexuality Can Improve HIV-AIDS Prevention Efforts: Key Research Issues and Directions.

ERIC Educational Resources Information Center

Kelly, Jeffrey A.; Kalichman, Seth C.

1995-01-01

Discusses curtailing the human immunodeficiency virus (HIV) by helping people reduce high-risk sexual behavior. Reviews research in the relationship contexts of sexuality, including variations in monogamy, condom use in affectionate versus casual relationships, sexual communication, and coercion. Notes policy and training issues related to human…

Sensitivity of biomechanical outcomes to independent variations of hindfoot and forefoot stiffness in foot prostheses.

PubMed

Adamczyk, Peter Gabriel; Roland, Michelle; Hahn, Michael E

2017-08-01

Many studies have reported the effects of different foot prostheses on gait, but most results cannot be generalized because the prostheses' properties are seldom reported. We varied hindfoot and forefoot stiffness in an experimental foot prosthesis, in increments of 15N/mm, and tested the parametric effects of these variations on treadmill walking in unilateral transtibial amputees, at speeds from 0.7 to 1.5m/s. We computed outcomes such as prosthesis energy return, center of mass (COM) mechanics, ground reaction forces, and joint mechanics, and computed their sensitivity to component stiffness. A stiffer hindfoot led to reduced prosthesis energy return, increased ground reaction force (GRF) loading rate, and greater stance-phase knee flexion and knee extensor moment. A stiffer forefoot resulted in reduced prosthetic-side ankle push-off and COM push-off work, and increased knee extension and knee flexor moment in late stance. The sensitivity parameters obtained from these tests may be useful in clinical prescription and further research into compensatory mechanisms of joint function. Copyright © 2017 Elsevier B.V. All rights reserved.

Lexical reorganization in Brazilian Portuguese: an articulatory study

PubMed Central

Meireles, A. R.; Barbosa, P. A.

2008-01-01

This work, which is couched in the theoretical framework of Articulatory Phonology, deals with the influence of speech rate on the change/variation from antepenultimate stress words into penultimate stress words in Brazilian Portuguese. Both acoustic and articulatory (EMMA) studies were conducted. On the acoustic side, results show different patterns of post-stressed vowel reduction according to the word type. Some words reduced their medial post-stressed vowels more than their final post-stressed vowels, and others reduced their final post-stressed vowels more than their medial post-stressed vowels. On the articulatory side, results show that the coarticulation degree of the post-stressed consonants increases with speech rate. Also, with the use of a measure called proportional consonantal interval (PCI), it was found in measurements of articulation that such measure is influenced by the word type. Three different groups of words were found according to their PCI. These results show how dynamical aspects influenced by speech rate increase are related to the lexical process of change/variation from antepenultimate stress words into penultimate ones. PMID:19885366

Computational Reduction of Specimen Noise to Enable Improved Thermography Characterization of Flaws in Graphite Polymer Composites

NASA Technical Reports Server (NTRS)

Winfree, William P.; Howell, Patricia A.; Zalameda, Joseph N.

2014-01-01

Flaw detection and characterization with thermographic techniques in graphite polymer composites are often limited by localized variations in the thermographic response. Variations in properties such as acceptable porosity, fiber volume content and surface polymer thickness result in variations in the thermal response that in general cause significant variations in the initial thermal response. These result in a "noise" floor that increases the difficulty of detecting and characterizing deeper flaws. A method is presented for computationally removing a significant amount of the "noise" from near surface porosity by diffusing the early time response, then subtracting it from subsequent responses. Simulations of the thermal response of a composite are utilized in defining the limitations of the technique. This method for reducing the data is shown to give considerable improvement characterizing both the size and depth of damage. Examples are shown for data acquired on specimens with fabricated delaminations and impact damage.

Automated mask and wafer defect classification using a novel method for generalized CD variation measurements

NASA Astrophysics Data System (ADS)

Verechagin, V.; Kris, R.; Schwarzband, I.; Milstein, A.; Cohen, B.; Shkalim, A.; Levy, S.; Price, D.; Bal, E.

2018-03-01

Over the years, mask and wafers defects dispositioning has become an increasingly challenging and time consuming task. With design rules getting smaller, OPC getting complex and scanner illumination taking on free-form shapes - the probability of a user to perform accurate and repeatable classification of defects detected by mask inspection tools into pass/fail bins is reducing. The critical challenging of mask defect metrology for small nodes ( < 30 nm) was reviewed in [1]. While Critical Dimension (CD) variation measurement is still the method of choice for determining a mask defect future impact on wafer, the high complexity of OPCs combined with high variability in pattern shapes poses a challenge for any automated CD variation measurement method. In this study, a novel approach for measurement generalization is presented. CD variation assessment performance is evaluated on multiple different complex shape patterns, and is benchmarked against an existing qualified measurement methodology.

Effect of Ice-Shell Thickness Variations on the Tidal Deformation of Enceladus

NASA Astrophysics Data System (ADS)

Choblet, G.; Cadek, O.; Behounkova, M.; Tobie, G.; Kozubek, T.

2015-12-01

Recent analysis of Enceladus's gravity and topography has suggested that the thickness of the ice shell significantly varies laterally - from 30-40 km in the south polar region to 60 km elsewhere. These variations may influence the activity of the geysers and increase the tidal heat production in regions where the ice shell is thinned. Using a model including a regional or global subsurface ocean and Maxwell viscoelasticity, we investigate the impact of these variations on the tidal deformation of the moon and its heat production. For that purpose, we use different numerical approaches - finite elements, local application of 1d spectral method, and a generalized spectral method. Results obtained with these three approaches for various models of ice-shell thickness variations are presented and compared. Implications of a reduced ice shell thickness for the south polar terrain activity are discussed.

Computational reduction of specimen noise to enable improved thermography characterization of flaws in graphite polymer composites

NASA Astrophysics Data System (ADS)

Winfree, William P.; Howell, Patricia A.; Zalameda, Joseph N.

2014-05-01

Flaw detection and characterization with thermographic techniques in graphite polymer composites are often limited by localized variations in the thermographic response. Variations in properties such as acceptable porosity, fiber volume content and surface polymer thickness result in variations in the thermal response that in general cause significant variations in the initial thermal response. These result in a "noise" floor that increases the difficulty of detecting and characterizing deeper flaws. A method is presented for computationally removing a significant amount of the "noise" from near surface porosity by diffusing the early time response, then subtracting it from subsequent responses. Simulations of the thermal response of a composite are utilized in defining the limitations of the technique. This method for reducing the data is shown to give considerable improvement characterizing both the size and depth of damage. Examples are shown for data acquired on specimens with fabricated delaminations and impact damage.

Spatial variation in climate mediates gene flow across an island archipelago.

PubMed

Logan, Michael L; Duryea, M C; Molnar, Orsolya R; Kessler, Benji J; Calsbeek, Ryan

2016-10-01

High levels of gene flow among partially isolated populations can overwhelm selection and limit local adaptation. This process, known as "gene swamping," can homogenize genetic diversity among populations and reduce the capacity of a species to withstand rapid environmental change. We studied brown anole lizards (Anolis sagrei) distributed across seven islands in The Bahamas. We used microsatellite markers to estimate gene flow among islands and then examined the correlation between thermal performance and island temperature. The thermal optimum for sprint performance was correlated with both mean and maximum island temperature, whereas performance breadth was not correlated with any measure of temperature variation. Gene flow between islands decreased as the difference between mean island temperatures increased, even when those islands were adjacent to one another. These data suggest that phenotypic variation is the result of either (1) local genetic adaptation with selection against immigrants maintaining variation in the thermal optimum, (2) irreversible forms of adaptive plasticity such that immigrants have reduced fitness, or (3) an interaction between fixed genetic differences and plasticity. In general, the patterns of gene flow we observed suggest that local thermal environments represent important ecological filters that can mediate gene flow on relatively fine geographic scales. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Differentiating causality and correlation in allometric scaling: ant colony size drives metabolic hypometry

PubMed Central

Ochs, Alison; Fewell, Jennifer H.; Harrison, Jon F.

2017-01-01

Metabolic rates of individual animals and social insect colonies generally scale hypometrically, with mass-specific metabolic rates decreasing with increasing size. Although this allometry has wide ranging effects on social behaviour, ecology and evolution, its causes remain controversial. Because it is difficult to experimentally manipulate body size of organisms, most studies of metabolic scaling depend on correlative data, limiting their ability to determine causation. To overcome this limitation, we experimentally reduced the size of harvester ant colonies (Pogonomyrmex californicus) and quantified the consequent increase in mass-specific metabolic rates. Our results clearly demonstrate a causal relationship between colony size and hypometric changes in metabolic rate that could not be explained by changes in physical density. These findings provide evidence against prominent models arguing that the hypometric scaling of metabolic rate is primarily driven by constraints on resource delivery or surface area/volume ratios, because colonies were provided with excess food and colony size does not affect individual oxygen or nutrient transport. We found that larger colonies had lower median walking speeds and relatively more stationary ants and including walking speed as a variable in the mass-scaling allometry greatly reduced the amount of residual variation in the model, reinforcing the role of behaviour in metabolic allometry. Following the experimental size reduction, however, the proportion of stationary ants increased, demonstrating that variation in locomotory activity cannot solely explain hypometric scaling of metabolic rates in these colonies. Based on prior studies of this species, the increase in metabolic rate in size-reduced colonies could be due to increased anabolic processes associated with brood care and colony growth. PMID:28228514

Adaptive influence of extrinsic and intrinsic factors on variation of incubation periods among tropical and temperate passerines

USGS Publications Warehouse

Martin, Thomas E.; Ton, Riccardo; Oteyza, Juan C.

2018-01-01

Understanding intrinsic (physiological) and extrinsic (e.g., temperature) causes of variation in embryonic development time (incubation period) is important because they can have different impacts on individual quality. Robert Ricklefs and colleagues have argued that longer incubation periods result primarily from intrinsic physiological programs that increase individual quality and adult survival. They claim that incubation periods are largely invariant and that extrinsic factors like temperature have little impact. We have argued that adult survival may be a cause rather than a consequence of much of the variation in embryonic development time. A reduction in extrinsic sources of annual adult mortality (e.g., migration, predation, nonbreeding-season mortality) favors reduced parental effort during incubation to minimize costs to future reproduction and survival. Reduced parental effort, in turn, manifests as cooler average egg temperatures that yield longer incubation periods. Ricklefs and colleagues mischaracterized our hypothesis and deconstructed their own incorrect version, while also making some incorrect statements. We show that reevaluation of previous evidence provided by this group actually supports a role of egg temperature for the variation in incubation periods. We also summarize other observational and experimental evidence that incubation periods are not invariant and that egg temperature has a strong causal influence on variation within and among species. In fact, egg temperature explains ∼60% of the difference in incubation periods among species. The remaining ∼40% reflects intrinsic physiological programs and other factors, potentially providing intrinsic benefits. Ultimately, annual adult mortality explains substantial variation in parental effort and egg temperature, and the latter strongly explains variation in incubation periods. Both intrinsic programs and extrinsic temperature effects need to be considered in attempts to understand incubation strategies.

Reducing Variation in the Assessment of Student Writing

ERIC Educational Resources Information Center

Hunter, Kerry; Docherty, Peter

2011-01-01

This paper extends the literature on grader variation and the role of moderation and socialisation processes in reducing this variation. It offers a fresh categorisation of academics' assessment beliefs and expectations, and uses this categorisation to analyse the interaction between implicit and explicit expectations in relation to grader…

Predicting the evolutionary dynamics of seasonal adaptation to novel climates in Arabidopsis thaliana

PubMed Central

Fournier-Level, Alexandre; Perry, Emily O.; Wang, Jonathan A.; Braun, Peter T.; Migneault, Andrew; Cooper, Martha D.; Metcalf, C. Jessica E.; Schmitt, Johanna

2016-01-01

Predicting whether and how populations will adapt to rapid climate change is a critical goal for evolutionary biology. To examine the genetic basis of fitness and predict adaptive evolution in novel climates with seasonal variation, we grew a diverse panel of the annual plant Arabidopsis thaliana (multiparent advanced generation intercross lines) in controlled conditions simulating four climates: a present-day reference climate, an increased-temperature climate, a winter-warming only climate, and a poleward-migration climate with increased photoperiod amplitude. In each climate, four successive seasonal cohorts experienced dynamic daily temperature and photoperiod variation over a year. We measured 12 traits and developed a genomic prediction model for fitness evolution in each seasonal environment. This model was used to simulate evolutionary trajectories of the base population over 50 y in each climate, as well as 100-y scenarios of gradual climate change following adaptation to a reference climate. Patterns of plastic and evolutionary fitness response varied across seasons and climates. The increased-temperature climate promoted genetic divergence of subpopulations across seasons, whereas in the winter-warming and poleward-migration climates, seasonal genetic differentiation was reduced. In silico “resurrection experiments” showed limited evolutionary rescue compared with the plastic response of fitness to seasonal climate change. The genetic basis of adaptation and, consequently, the dynamics of evolutionary change differed qualitatively among scenarios. Populations with fewer founding genotypes and populations with genetic diversity reduced by prior selection adapted less well to novel conditions, demonstrating that adaptation to rapid climate change requires the maintenance of sufficient standing variation. PMID:27140640

Predicting the evolutionary dynamics of seasonal adaptation to novel climates in Arabidopsis thaliana.

PubMed

Fournier-Level, Alexandre; Perry, Emily O; Wang, Jonathan A; Braun, Peter T; Migneault, Andrew; Cooper, Martha D; Metcalf, C Jessica E; Schmitt, Johanna

2016-05-17

Predicting whether and how populations will adapt to rapid climate change is a critical goal for evolutionary biology. To examine the genetic basis of fitness and predict adaptive evolution in novel climates with seasonal variation, we grew a diverse panel of the annual plant Arabidopsis thaliana (multiparent advanced generation intercross lines) in controlled conditions simulating four climates: a present-day reference climate, an increased-temperature climate, a winter-warming only climate, and a poleward-migration climate with increased photoperiod amplitude. In each climate, four successive seasonal cohorts experienced dynamic daily temperature and photoperiod variation over a year. We measured 12 traits and developed a genomic prediction model for fitness evolution in each seasonal environment. This model was used to simulate evolutionary trajectories of the base population over 50 y in each climate, as well as 100-y scenarios of gradual climate change following adaptation to a reference climate. Patterns of plastic and evolutionary fitness response varied across seasons and climates. The increased-temperature climate promoted genetic divergence of subpopulations across seasons, whereas in the winter-warming and poleward-migration climates, seasonal genetic differentiation was reduced. In silico "resurrection experiments" showed limited evolutionary rescue compared with the plastic response of fitness to seasonal climate change. The genetic basis of adaptation and, consequently, the dynamics of evolutionary change differed qualitatively among scenarios. Populations with fewer founding genotypes and populations with genetic diversity reduced by prior selection adapted less well to novel conditions, demonstrating that adaptation to rapid climate change requires the maintenance of sufficient standing variation.

Coding response to a case-mix measurement system based on multiple diagnoses.

PubMed

Preyra, Colin

2004-08-01

To examine the hospital coding response to a payment model using a case-mix measurement system based on multiple diagnoses and the resulting impact on a hospital cost model. Financial, clinical, and supplementary data for all Ontario short stay hospitals from years 1997 to 2002. Disaggregated trends in hospital case-mix growth are examined for five years following the adoption of an inpatient classification system making extensive use of combinations of secondary diagnoses. Hospital case mix is decomposed into base and complexity components. The longitudinal effects of coding variation on a standard hospital payment model are examined in terms of payment accuracy and impact on adjustment factors. Introduction of the refined case-mix system provided incentives for hospitals to increase reporting of secondary diagnoses and resulted in growth in highest complexity cases that were not matched by increased resource use over time. Despite a pronounced coding response on the part of hospitals, the increase in measured complexity and case mix did not reduce the unexplained variation in hospital unit cost nor did it reduce the reliance on the teaching adjustment factor, a potential proxy for case mix. The main implication was changes in the size and distribution of predicted hospital operating costs. Jurisdictions introducing extensive refinements to standard diagnostic related group (DRG)-type payment systems should consider the effects of induced changes to hospital coding practices. Assessing model performance should include analysis of the robustness of classification systems to hospital-level variation in coding practices. Unanticipated coding effects imply that case-mix models hypothesized to perform well ex ante may not meet expectations ex post.

Increased extinction potential of insular fish populations with reduced life history variation and low genetic diversity.

PubMed

Hellmair, Michael; Kinziger, Andrew P

2014-01-01

Theoretical work has shown that reduced phenotypic heterogeneity leads to population instability and can increase extinction potential, yet few examples exist of natural populations that illustrate how varying levels expressed diversity may influence population persistence, particularly during periods of stochastic environmental fluctuation. In this study, we assess levels of expressed variation and genetic diversity among demographically independent populations of tidewater goby (Eucyclogobius newberryi), show that reductions in both factors typically coincide, and describe how low levels of diversity contribute to the extinction risk of these isolated populations. We illustrate that, for this annual species, continuous reproduction is a safeguard against reproductive failure by any one population segment, as natural, stochastically driven salinity increases frequently result in high mortality among juvenile individuals. Several study populations deviated from the natural pattern of year-round reproduction typical for the species, rendering those with severely truncated reproductive periods vulnerable to extinction in the event of environmental fluctuation. In contrast, demographically diverse populations are more likely to persist through such periods through the continuous presence of adults with broader physiological tolerance to abrupt salinity changes. Notably, we found a significant correlation between genetic diversity and demographic variation in the study populations, which could be the result of population stressors that restrict both of these diversity measures simultaneously, or suggestive of a causative relationship between these population characteristics. These findings demonstrate the importance of biocomplexity at the population level, and assert that the maintenance of diversity contributes to population resilience and conservation of this endangered species.

Epidemiological aspects of ageing.

PubMed Central

Khaw, K T

1997-01-01

A major societal challenge is to improve quality of life and prevent or reduce disability and dependency in an ageing population. Increasing age is associated with increasing risk of disability and loss of independence, due to functional impairments such as loss of mobility, hearing and vision; a major issue must be how far disability can be prevented. Ageing is associated with loss of bone tissue, reduction in muscle mass, reduced respiratory function, decline in cognitive function, rise in blood pressure and macular degeneration which predispose to disabling conditions such as osteoporosis, heart disease, dementia and blindness. However, there are considerable variations in different communities in terms of the rate of age-related decline. Large geographic and secular variations in the age-adjusted incidence of major chronic diseases such as stroke, hip fracture, coronary heart disease, cancer, visual loss from cataract, glaucoma and macular degeneration suggest strong environmental determinants in diet, physical activity and smoking habit. The evidence suggests that a substantial proportion of chronic disabling conditions associated with ageing are preventable, or at least postponable and not an inevitable accompaniment of growing old. Postponement or prevention of these conditions may not only increase longevity, but, more importantly, reduce the period of illnesses such that the majority of older persons may live high-quality lives, free of disability, until very shortly before death. We need to understand better the factors influencing the onset of age-related disability in the population, so that we have appropriate strategies to maintain optimal health in an ageing population. PMID:9460067

Epidemiological aspects of ageing.

PubMed

Khaw, K T

1997-12-29

A major societal challenge is to improve quality of life and prevent or reduce disability and dependency in an ageing population. Increasing age is associated with increasing risk of disability and loss of independence, due to functional impairments such as loss of mobility, hearing and vision; a major issue must be how far disability can be prevented. Ageing is associated with loss of bone tissue, reduction in muscle mass, reduced respiratory function, decline in cognitive function, rise in blood pressure and macular degeneration which predispose to disabling conditions such as osteoporosis, heart disease, dementia and blindness. However, there are considerable variations in different communities in terms of the rate of age-related decline. Large geographic and secular variations in the age-adjusted incidence of major chronic diseases such as stroke, hip fracture, coronary heart disease, cancer, visual loss from cataract, glaucoma and macular degeneration suggest strong environmental determinants in diet, physical activity and smoking habit. The evidence suggests that a substantial proportion of chronic disabling conditions associated with ageing are preventable, or at least postponable and not an inevitable accompaniment of growing old. Postponement or prevention of these conditions may not only increase longevity, but, more importantly, reduce the period of illnesses such that the majority of older persons may live high-quality lives, free of disability, until very shortly before death. We need to understand better the factors influencing the onset of age-related disability in the population, so that we have appropriate strategies to maintain optimal health in an ageing population.

Increased apomixis expression concurrent with genetic and epigenetic variation in a newly synthesized Eragrostis curvula polyploid

NASA Astrophysics Data System (ADS)

Zappacosta, Diego C.; Ochogavía, Ana C.; Rodrigo, Juan M.; Romero, José R.; Meier, Mauro S.; Garbus, Ingrid; Pessino, Silvina C.; Echenique, Viviana C.

2014-04-01

Eragrostis curvula includes biotypes reproducing through obligate and facultative apomixis or, rarely, full sexuality. We previously generated a ``tetraploid-dihaploid-tetraploid'' series of plants consisting of a tetraploid apomictic plant (T), a sexual dihaploid plant (D) and a tetraploid artificial colchiploid (C). Initially, plant C was nearly 100% sexual. However, its capacity to form non-reduced embryo sacs dramatically increased over a four year period (2003-2007) to reach levels of 85-90%. Here, we confirmed high rates of apomixis in plant C, and used AFLPs and MSAPs to characterize the genetic and epigenetic variation observed in this plant in 2007 as compared to 2003. Of the polymorphic sequences, some had no coding potential whereas others were homologous to retrotransposons and/or protein-coding-like sequences. Our results suggest that in this particular plant system increased apomixis expression is concurrent with genetic and epigenetic modifications, possibly involving transposable elements.

Modeled Carbon Cycle Responses to Altered Precipitation Amount and Interannual Variation in Desert Grassland

NASA Astrophysics Data System (ADS)

Liang, G.; Wilcox, K.; Rudgers, J.; Litvak, M. E.; Newsome, S. D.; Collins, S. L.; Pockman, W.; Luo, Y.

2017-12-01

Altered amounts and increased interannual variation of precipitation are likely to occur on a regional to global scale in the late 21st Century, yet understanding the interactive effects of these changes on ecosystem processes is limited. Here, we modeled the responses of the carbon cycle in a desert grassland at the Sevilleta National Wildlife Refuge (SEV) to changes in precipitation amount and interannual variation using the Terrestrial Ecosystem model. After model calibration, we generated 100-year hourly weather data by randomly repeated sampling of observed hourly weather data at SEV from 2000 to 2012. We then modified this 100-year time series to create six climate scenarios: (1) ambient (AMB); (2) increased air temperature by 4.3 °C in summer and 3.3 °C in other seasons for each year (IT); (3) 20% decreased precipitation amount for every event (DP); (4) combined IT and DP (DPT); (5) 100% increased precipitation interannual variance without changing the mean (IV); (6) combined IT and IV (IVT). Our results showed IV significantly increased the sensitivity of NPP to continuous extreme drought. In addition, the increased number of extreme drought years caused by IV exacerbated the negative influence of individual extreme drought events on soil organic carbon (SOC). The IV climate scenario showed the highest interannual variance of carbon fluxes and SOC, but increased temperature reduced this variance. DP and IV decreased NPP by 10.7% and 18.3% compared with AMB, respectively, and the negative impact of IV on NPP was more severe than that of DP. Our results indicate that the increased interannual variation in precipitation could have more severe impacts on terrestrial ecosystems that exceed the decrease in predicted average annual precipitation.

Radius of curvature variations for annular, dark hollow and flat topped beams in turbulence

NASA Astrophysics Data System (ADS)

Eyyuboğlu, H. T.; Baykal, Y. K.; Ji, X. L.

2010-06-01

For propagation in turbulent atmosphere, the radius of curvature variations for annular, dark hollow and flat topped beams are examined under a single formulation. Our results show that for collimated beams, when examined against propagation length, the dark hollow, flat topped and annular Gaussian beams behave nearly the same as the Gaussian beam, but have larger radius of curvature values. Increased partial coherence and turbulence levels tend to lower the radius of curvature. Bigger source sizes on the other hand give rise to larger radius of curvature. Dark hollow and flat topped beams have reduced radius of curvature at longer wavelengths, whereas the annular Gaussian beam seems to be unaffected by wavelength changes; the radius of curvature of the Gaussian beam meanwhile rises with increasing wavelength.

Downstream movement of fall Chinook salmon juveniles in the lower Snake River reservoirs during winter and early spring

USGS Publications Warehouse

Tiffan, Kenneth F.; Kock, Tobias J.; Connor, William P.; Mullins, Frank; Steinhorst, R. Kirk

2012-01-01

We conducted a 3-year radiotelemetry study in the lower Snake River to (1) determine whether juvenile fall Chinook salmon Oncorhynchus tshawytscha pass dams during winter, when bypass systems and structures designed to prevent mortality are not operated; (2) determine whether downstream movement rate varies annually, seasonally, and from reservoir to reservoir; and (3) identify some of the factors that contribute to annual, seasonal, and spatial variation in downstream movement rate. Fall Chinook salmon juveniles moved downstream up to 169 km and at a sufficiently fast rate (7.5 km/d) such that large percentages (up to 93%) of the fish passed one or more dams during the winter. Mean downstream movement rate varied annually (9.2–11.3 km/d), increased from winter (7.5 km/d) to spring (16.4 km/d), and increased (from 6.9 to 16.8 km/d) as fish moved downstream from reservoir to reservoir. Fish condition factor at tagging explained some of the annual variation in downstream movement rate, whereas water particle velocity and temperature explained portions of the seasonal variation. An increase in migrational disposition as fish moved downstream helped to explain the spatial variation. The potential cost of winter movement might be reduced survival due to turbine passage at a time when the bypass systems and spillway passage structures are not operated. Efforts to understand and increase passage survival of winter migrants in large impoundments might help to rehabilitate some imperiled anadromous salmonid populations.

Understanding and Controlling Sialylation in a CHO Fc-Fusion Process

PubMed Central

Lewis, Amanda M.; Croughan, William D.; Aranibar, Nelly; Lee, Alison G.; Warrack, Bethanne; Abu-Absi, Nicholas R.; Patel, Rutva; Drew, Barry; Borys, Michael C.; Reily, Michael D.; Li, Zheng Jian

2016-01-01

A Chinese hamster ovary (CHO) bioprocess, where the product is a sialylated Fc-fusion protein, was operated at pilot and manufacturing scale and significant variation of sialylation level was observed. In order to more tightly control glycosylation profiles, we sought to identify the cause of variability. Untargeted metabolomics and transcriptomics methods were applied to select samples from the large scale runs. Lower sialylation was correlated with elevated mannose levels, a shift in glucose metabolism, and increased oxidative stress response. Using a 5-L scale model operated with a reduced dissolved oxygen set point, we were able to reproduce the phenotypic profiles observed at manufacturing scale including lower sialylation, higher lactate and lower ammonia levels. Targeted transcriptomics and metabolomics confirmed that reduced oxygen levels resulted in increased mannose levels, a shift towards glycolysis, and increased oxidative stress response similar to the manufacturing scale. Finally, we propose a biological mechanism linking large scale operation and sialylation variation. Oxidative stress results from gas transfer limitations at large scale and the presence of oxygen dead-zones inducing upregulation of glycolysis and mannose biosynthesis, and downregulation of hexosamine biosynthesis and acetyl-CoA formation. The lower flux through the hexosamine pathway and reduced intracellular pools of acetyl-CoA led to reduced formation of N-acetylglucosamine and N-acetylneuraminic acid, both key building blocks of N-glycan structures. This study reports for the first time a link between oxidative stress and mammalian protein sialyation. In this study, process, analytical, metabolomic, and transcriptomic data at manufacturing, pilot, and laboratory scales were taken together to develop a systems level understanding of the process and identify oxygen limitation as the root cause of glycosylation variability. PMID:27310468

Preparation of lactic acid bacteria fermented wheat-yoghurt mixtures.

PubMed

Magala, Michal; Kohajdová, Zlatica; Karovičová, Jolana

2013-01-01

Tarhana, a wheat-yoghurt fermented mixture, is considered as a good source of saccharides, proteins, some vitamins and minerals. Moreover, their preparation is inexpensive and lactic acid fermentation offers benefits like product preservation, enhancement of nutritive value and sensory properties improvement. The aim of this work was to evaluate changes of some chemical parameters during fermentation of tarhana, when the level of salt and amount of yoghurt used were varied. Some functional and sensory characteristics of the fi nal product were also determined. Chemical analysis included determination of pH, titrable acidity, content of reducing saccharides, lactic, acetic and citric acid. Measured functional properties of tarhana powder were foaming capacity, foam stability, water absorption capacity, oil absorption capacity and emulsifying activity. Tarhana soups samples were evaluated for their sensory characteristics (colour, odor, taste, consistency and overall acceptability). Fermentation of tarhana by lactic acid bacteria and yeasts led to decrease in pH, content of reducing saccharides and citric acid, while titrable acidity and concentration of lactic and acetic acid increased. Determination of functional properties of tarhana powder showed, that salt absence and increased amount of yoghurt in tarhana recipe reduced foaming capacity and oil absorption capacity, whereas foam stability and water absorption capacity were improved. Sensory evaluation of tarhana soups showed that variations in tarhana recipe adversly affected sensory parameters of fi nal products. Variations in tarhana recipe (salt absence, increased proportion of yoghurt) led to changes in some chemical parameters (pH, titrable acidity, reducing saccharides, content of lactic, acetic and citric acid). Functional properties were also affected with changed tarhana recipe. Sensory characteristics determination showed, that standard tarhana fermented for 144 h had the highest overall acceptability.

The ITSG-Grace2014 Gravity Field Model

NASA Astrophysics Data System (ADS)

Kvas, Andreas; Mayer-Gürr, Torsten; Zehenter, Norbert; Klinger, Beate

2015-04-01

The ITSG-Grace2014 GRACE-only gravity field model consists of a high resolution unconstrained static model (up to degree 200) with trend and annual signal, monthly unconstrained solutions with different spatial resolutions as well as daily snapshots derived by using a Kalman smoother. Apart from the estimated spherical harmonic coefficients, full variance-covariance matrices for the monthly solutions and the static gravity field component are provided. Compared to the previous release, multiple improvements in the processing chain are implemented: updated background models, better ionospheric modeling for GPS observations, an improved satellite attitude by combination of star camera and angular accelerations, estimation of K-band antenna center variations within the gravity field recovery process as well as error covariance function determination. Furthermore, daily gravity field variations have been modeled in the adjustment process to reduce errors caused by temporal leakage. This combined estimation of daily gravity variations field variations together with the static gravity field component represents a computational challenge due to the significantly increased parameter count. The modeling of daily variations up to a spherical harmonic degree of 40 for the whole GRACE observation period results in a system of linear equations with over 6 million unknown gravity field parameters. A least squares adjustment of this size is not solvable in a sensible time frame, therefore measures to reduce the problem size have to be taken. The ITSG-Grace2014 release is presented and selected parts of the processing chain and their effect on the estimated gravity field solutions are discussed.

Fertility Regulation in an Economic Crisis

PubMed Central

McKelvey, Christopher; Thomas, Duncan; Frankenberg, Elizabeth

2015-01-01

Substantial international aid is spent reducing the cost of contraception in developing countries, as part of a larger effort to reduce global fertility and increase investment per child worldwide. The importance for fertility behaviors of keeping contraceptive prices low, however, remains unclear. Targeting of subsidies and insufficient price variation have hindered prior attempts to estimate the effect of monetary and non-monetary contraceptive costs on fertility behavior. Using longitudinal survey data from the Indonesia Family Life Survey, we exploit dramatic variation in prices and incomes that was induced by the economic crisis in the late 1990s to pin down the effect of contraceptive availability and costs as well as household resources on contraceptive use and method choice. The results are unambiguous: monetary costs of contraceptives and levels of family economic resources have a very small (and well-determined) impact on contraceptive use and choice of method. PMID:25843969

Sex education and adolescent sexual behavior: do community characteristics matter?

PubMed

Kraft, Joan Marie; Kulkarni, Aniket; Hsia, Jason; Jamieson, Denise J; Warner, Lee

2012-09-01

Studies point to variation in the effects of formal sex education on sexual behavior and contraceptive use by individual and community characteristics. Using the 2002 National Survey of Family Growth, we explored associations between receipt of sex education and intercourse by age 15, intercourse by the time of the interview and use of effective contraception at first sex among 15-19-year-olds, stratified by quartiles of three community characteristics and adjusted for demographics. Across all quartiles of community characteristics, sex education reduced the odds of having sex by age 15. Sex education resulted in reduced odds of having sex by the date of the interview and increased odds of using contraception in the middle quartiles of community characteristics. Variation in the effects of sex education should be explored. Research might focus on programmatic differences by community type and programmatic needs in various types of communities. Published by Elsevier Inc.

Climatic factors contributing to long-term variations in surface fine dust concentration in the United States

NASA Astrophysics Data System (ADS)

Pu, Bing; Ginoux, Paul

2018-03-01

High concentrations of dust particles can cause respiratory problems and increase non-accidental mortality. Studies found fine dust (with an aerodynamic diameter of less than 2.5 µm) is an important component of the total PM2.5 mass in the western and central US in spring and summer and has positive trends. This work examines climatic factors influencing long-term variations in surface fine dust concentration in the US using station data from the Interagency Monitoring Protected Visual Environments (IMPROVE) network during 1990-2015. The variations in the fine dust concentration can be largely explained by the variations in precipitation, surface bareness, and 10 m wind speed. Moreover, including convective parameters such as convective inhibition (CIN) and convective available potential energy (CAPE) that reveal the stability of the atmosphere better explains the variations and trends over the Great Plains from spring to fall.While the positive trend of fine dust concentration in the southwestern US in spring is associated with precipitation deficit, the increase in fine dust over the central Great Plains in summer is largely associated with enhanced CIN and weakened CAPE, which are caused by increased atmospheric stability due to surface drying and lower-troposphere warming. The strengthening of the Great Plains low-level jet also contributes to the increase in fine dust concentration in the central Great Plains in summer via its positive correlation with surface winds and negative correlation with CIN.Summer dusty days in the central Great Plains are usually associated with a westward extension of the North Atlantic subtropical high that intensifies the Great Plains low-level jet and also results in a stable atmosphere with subsidence and reduced precipitation.

Conditional cold avoidance drives between-population variation in germination behaviour in Calluna vulgaris.

PubMed

Spindelböck, Joachim P; Cook, Zoë; Daws, Matthew I; Heegaard, Einar; Måren, Inger E; Vandvik, Vigdis

2013-09-01

Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season. Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range. Incubation treatments varied from 10 to 25 °C, and germination performance across populations was analysed in relation to temperature conditions at the seed collection locations. Seeds from all populations germinated rapidly and to high final percentages under the warmer incubation temperatures. Under low incubation temperatures, cold-climate populations had significantly lower germination rates and percentages than warm-climate populations. While germination rates and percentages also increased with seed mass, seed mass did not vary along the climatic gradients, and therefore did not explain the variation in germination responses. Variation in germination responses among Calluna populations was consistent with increased temperature requirements for germination towards colder climates, indicating a cold-avoidance germination strategy conditional on the temperature at the seeds' origin. Along a gradient of increasing temperatures this suggests a shift in selection pressures on germination from climatic adversity (i.e. low temperatures and potential frost risk in early or late season) to competitive performance and better exploitation of the entire growing season.

Conditional cold avoidance drives between-population variation in germination behaviour in Calluna vulgaris

PubMed Central

Spindelböck, Joachim P.; Cook, Zoë; Daws, Matthew I.; Heegaard, Einar; Måren, Inger E.; Vandvik, Vigdis

2013-01-01

Background and Aims Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season. Methods Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range. Incubation treatments varied from 10 to 25 °C, and germination performance across populations was analysed in relation to temperature conditions at the seed collection locations. Key Results Seeds from all populations germinated rapidly and to high final percentages under the warmer incubation temperatures. Under low incubation temperatures, cold-climate populations had significantly lower germination rates and percentages than warm-climate populations. While germination rates and percentages also increased with seed mass, seed mass did not vary along the climatic gradients, and therefore did not explain the variation in germination responses. Conclusions Variation in germination responses among Calluna populations was consistent with increased temperature requirements for germination towards colder climates, indicating a cold-avoidance germination strategy conditional on the temperature at the seeds' origin. Along a gradient of increasing temperatures this suggests a shift in selection pressures on germination from climatic adversity (i.e. low temperatures and potential frost risk in early or late season) to competitive performance and better exploitation of the entire growing season. PMID:23884396

SU-F-J-71: Improving CT Quality for Radiation Therapy Planning and Delivery Guidance Using a Non-Linear Contrast Enhancement Technique

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

Noid, G; Tai, A; Li, X

2016-06-15

Purpose: Advanced image post-processing techniques which enhance soft-tissue contrast in CT have not been widely employed for RT planning or delivery guidance. The purpose of this work is to assess the soft-tissue contrast enhancement from non-linear contrast enhancing filters and its impact in RT. The contrast enhancement reduces patient alignment uncertainties. Methods: Non-linear contrast enhancing methods, such as Best Contrast (Siemens), amplify small differences in X-ray attenuation between two adjacent structure without significantly increasing noise. Best Contrast (BC) separates a CT into two frequency bands. The low frequency band is modified by a non-linear scaling function before recombination with themore » high frequency band. CT data collected using a CT-on-rails (Definition AS Open, Siemens) during daily CT-guided RT for 6 prostate cancer patients and an image quality phantom (The Phantom Laboratory) were analyzed. Images acquired with a standard protocol (120 kVp, 0.6 pitch, 18 mGy CTDIvol) were processed before comparison to the unaltered images. Contrast and noise were measured in the the phantom. Inter-observer variation was assessed by placing prostate contours on the 12 CT study sets, 6 enhanced and 6 unaltered, in a blinded study involving 8 observers. Results: The phantom data demonstrate that BC increased the contrast between the 1.0% supra-slice element and the background substrate by 46.5 HU while noise increased by only 2.3 HU. Thus the contrast to noise ratio increased from 1.28 to 6.71. Furthermore, the variation in centroid position of the prostate contours was decreased from 1.3±0.4 mm to 0.8±0.3 mm. Thus the CTV-to-PTV margin was reduced by 1.1 mm. The uncertainty in delineation of the prostate/rectum edge decreased by 0.5 mm. Conclusion: As demonstrated in phantom and patient scans the BC filter accentuates soft-tissue contrast. This enhancement leads to reduced inter-observer variation, which should improve RT planning and delivery. Supported by Siemens.« less

Slags in a Large Variation Range of Oxygen Potential Based on the Ion and Molecule Coexistence Theory

NASA Astrophysics Data System (ADS)

Yang, Xue-Min; Li, Jin-Yan; Zhang, Meng; Chai, Guo-Min; Zhang, Jian

2014-12-01

A thermodynamic model for predicting sulfide capacity of CaO-FeO-Fe2O3-Al2O3-P2O5 slags in a large variation range of oxygen potential corresponding to mass percentage of FetO from 1.88 to 55.50 pct, i.e., IMCT- model, has been developed by coupling with the deduced desulfurization mechanism of the slags based on the ion and molecule coexistence theory (IMCT). The developed IMCT- model has been verified through comparing the determined sulfide capacity after Ban-ya et al.[20] with the calculated by the developed IMCT- model and the calculated by the reported sulfide capacity models such as the KTH model. Mass percentage of FetO as 6.75 pct corresponding to the mass action concentration of FetO as 0.0637 or oxygen partial as 2.27 × 10-6 Pa is the criterion for distinguishing reducing and oxidizing zones for the slags. Sulfide capacity of the slags in reducing zone is controlled by reaction ability of CaO regardless of slag oxidization ability. However, sulfide capacity of the slags in oxidizing zone shows an obvious increase tendency with the increasing of slag oxidization ability. Sulfide capacity of the slags in reducing zone keeps almost constant with variation of the simplified complex basicity (pct CaO)/((pct Al2O3) + (pct P2O5)), or optical basicity, or the mass action concentration ratios of N FeO/ N CaO, , , and . Sulfide capacity of the slags in oxidizing zone shows an obvious increase with the increasing of the simplified complex basicity (pct CaO)/((pct Al2O3) + (pct P2O5)) or optical basicity, or the aforementioned mass action concentration ratios. Thus, the aforementioned mass action concentration ratios and the corresponding mass percentage ratios of various iron oxides to basic oxide CaO are recommended to represent the comprehensive effect of various iron oxides and basic oxide CaO on sulfide capacity of the slags.

Unravelling variation in feeding, social interaction and growth patterns among pigs using an agent-based model.

PubMed

Boumans, Iris J M M; de Boer, Imke J M; Hofstede, Gert Jan; Bokkers, Eddie A M

2018-07-01

Domesticated pigs, Sus scrofa, vary considerably in feeding, social interaction and growth patterns. This variation originates partly from genetic variation that affects physiological factors and partly from behavioural strategies (avoid or approach) in competitive food resource situations. Currently, it is unknown how variation in physiological factors and in behavioural strategies among animals contributes to variation in feeding, social interaction and growth patterns in animals. The aim of this study was to unravel causation of variation in these patterns among pigs. We used an agent-based model to explore the effects of physiological factors and behavioural strategies in pigs on variation in feeding, social interaction and growth patterns. Model results show that variation in feeding, social interaction and growth patterns are caused partly by chance, such as time effects and coincidence of conflicts. Furthermore, results show that seemingly contradictory empirical findings in literature can be explained by variation in pig characteristics (i.e. growth potential, positive feedback, dominance, and coping style). Growth potential mainly affected feeding and growth patterns, whereas positive feedback, dominance and coping style affected feeding patterns, social interaction patterns, as well as growth patterns. Variation in behavioural strategies among pigs can reduce aggression at group level, but also make some pigs more susceptible to social constraints inhibiting them from feeding when they want to, especially low-ranking pigs and pigs with a passive coping style. Variation in feeding patterns, such as feeding rate or meal frequency, can indicate social constraints. Feeding patterns, however, can say something different about social constraints at group versus individual level. A combination of feeding patterns, such as a decreased feed intake, an increased feeding rate, and an increased meal frequency might, therefore, be needed to measure social constraints at individual level. Copyright © 2018 Elsevier Inc. All rights reserved.

Biomonitoring role of some cellular markers during heat stress-induced changes in highly representative fresh water mollusc, Bellamya bengalensis: Implication in climate change and biological adaptation.

PubMed

Dutta, Sangita Maiti; Mustafi, Soumyajit Banerjee; Raha, Sanghamitra; Chakraborty, Susanta Kumar

2018-08-15

Owing to increasing concern of global climate-change, temperature rise is of great interest which can be primarily evaluated from the seasonal variations in some organisms. Aquatic environment can be extremely stressful to its inhabitants because most of them are poikilothermous. In the present study, attempt was made to evaluate the biological effects of oxidative-stress and adaptive/antioxidant capacities during temperature variations (36-40 °C for 24hrs to 72hrs) in Bellamya bengalensis both in environmental and laboratory conditions by testing some biomarkers like HSP70, catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione reductase (GR). The biomarker potency of the molecules and the anti-oxidative metabolic-network was postulated and extrapolated to find its resemblance to the climate-change associated organismal variations. In a natural and eco-restored environment in the Eastern part of India, 10-20 fold increases in CAT, SOD and HSP70 protein expressions (Western blot results) were noticed in Bellamya paralleling to their increased enzymatic activities (gel zymogram studies) due to the seasonal (summer versus winter) temperature variation. It is evident from the consecutive three years' study that this variation resulted in the unfavorable physico-chemical changes of water quality parameters like dissolved oxygen, biochemical oxygen demand, alkalinity and consequently decreased the animal density in summer. And that was revived due to their higher reproduction-rate in post rainy/winter season when temperature normalizes resulting in a restoration of favorable environment. In laboratory condition, the reduced GR and increased GPx indicated the oxidative damage as evident by higher tissue MDA level following to higher mortality. Changes in SOD and CAT activities suggest activation of physiological mechanism to scavenge the ROS produced during heat stress. However, when mortality increased at different time points (36 °C - 72 h and 38 °C - 72 h), these enzyme activities also decreased as they failed to save the tissues from ROS. The results suggest that temperature variation does alter the active oxygen metabolism by modulating antioxidant enzyme activities, which can be used as biomarker to detect sub-lethal effects of climate change-associated pollution. The parity in environmental and laboratory experimental results may justify this laboratory experiment as model heat-stress experiment and indicate temperature as a universal stressor which alone or in combination with other water parameters initiates a consistent adapting behavior. The Bellamya bengalensis being the highest faunal representative in its habitat may serve as a good bioindicator species. Copyright © 2018. Published by Elsevier Inc.

Identification of a barrier height threshold where brook trout population genetic diversity, differentiation, and relatedness are affected

Treesearch

Anne Timm; Eric Hallerman; Andy Dolloff; Mark Hudy; Randall Kolka

2016-01-01

The overall goal of the study was to evaluate effects of landscape features, barriers, on Brook Trout Salvelinus fontinalis population genetics and to identify a potential barrier height threshold where genetic diversity was reduced upstream of the barrier and differentiation and relatedness increase. We screened variation at eight...

Fine-scale spatial climate variation and drought mediate the likelihood of reburning

Treesearch

Sean A. Parks; Marc‐Andre Parisien; Carol Miller; Lisa M. Holsinger; Larry Scott Baggett

2018-01-01

In many forested ecosystems, it is increasingly recognized that the probability of burning is substantially reduced within the footprint of previously burned areas. This self‐limiting effect of wildland fire is considered a fundamental emergent property of ecosystems and is partly responsible for structuring landscape heterogeneity (i.e., mosaics of different age...

Inter-specific variation in avian responses to human disturbance

Treesearch

Daniel T. Blumstein; Esteban Fernandez-Juricic; Patrick A. Zollner; Susan C. Garity

2005-01-01

1. Increasing urbanization and recreational activities around and within biodiversity hotspots require an understanding of how to reduce the impacts of human disturbance on more than a single species; however, we lack a general framework to study multiple species. One approach is to expand on knowledge about the theory of anti-predator behaviour to understand and...

Variations and Determinants of Hospital Costs for Acute Stroke in China

PubMed Central

Wei, Jade W.; Heeley, Emma L.; Jan, Stephen; Huang, Yining; Huang, Qifang; Wang, Ji-Guang; Cheng, Yan; Xu, En; Yang, Qidong; Anderson, Craig S.

2010-01-01

Background The burden of stroke is high and increasing in China. We modelled variations in, and predictors of, the costs of hospital care for patients with acute stroke in China. Methods and Findings Baseline characteristics and hospital costs for 5,255 patients were collected using the prospective register-based ChinaQUEST study, conducted in 48 Level 3 and 14 Level 2 hospitals in China during 2006–2007. Ordinary least squares estimation was used to determine factors associated with hospital costs. Overall mean cost of hospitalisation was 11,216 Chinese Yuan Renminbi (CNY) (≈US$1,602) per patient, which equates to more than half the average annual wage in China. Variations in cost were largely attributable to stroke severity and length of hospital stay (LOS). Model forecasts showed that reducing LOS from the mean of 20 days for Level 3 and 18 days for Level 2 hospitals to a duration of 1 week, which is common among Western countries, afforded cost reductions of 49% and 19%, respectively. Other lesser determinants varied by hospital level: in Level 3 hospitals, health insurance and the occurrence of in-hospital complications were each associated with 10% and 18% increases in cost, respectively, whilst treatment in a teaching hospital was associated with approximately 39% decrease in cost on average. For Level 2 hospitals, stroke due to intracerebral haemorrhage was associated with a 19% greater cost than for ischaemic stroke. Conclusions Changes to hospital policies to standardise resource use and reduce the variation in LOS could attenuate costs and improve efficiencies for acute stroke management in China. The success of these strategies will be enhanced by broader policy initiatives currently underway to reform hospital reimbursement systems. PMID:20927384

Genetic variation in C-reactive protein (CRP) in relation to colon and rectal cancer risk and survival

PubMed Central

Slattery, Martha L.; Curtin, Karen; Poole, Elizabeth M.; Duggan, David J.; Samowitz, Wade S.; Peters, Ulrike; Caan, Bette J.; Potter, John D.; Ulrich, Cornelia M.

2011-01-01

Background C-reactive protein (CRP), a biomarker of inflammation has been shown to be influenced by genetic variation in the CRP gene. Methods In this study, we test the hypothesis that genetic variation in CRP influences both the risk of developing colon and rectal cancer and survival. Two population-based studies of colon cancer (n=1574 cases, 1970 controls) and rectal (n=791 cases, 999 controls) were conducted. We evaluated four CRP tagSNPs: rs1205 (G>A, 3’ UTR); rs1417938 (T>A, intron); rs1800947 (G>C, L184L); and rs3093075 (C>A, 3’ flanking). Results The CRP rs1205 AA genotype was associated with an increased risk of colon cancer (OR 1.3, 95%CI 1.1-1.7), whereas the rs3093075 A allele was associated with a reduced risk of rectal cancer (OR 0.7, 95%CI 0.5-0.9). The strongest association for the rs1205 polymorphism and colon cancer was observed among those with KRAS2 mutations (OR 1.5, 95%CI 1.1-2.0). The CRP rs1205 AA genotype also was associated with an increased risk of CIMP+ rectal tumors (OR 2.5, 95% CI 1.2-5.3); conversely, the rs1417938 A allele was associated with a reduced risk of CIMP+ rectal tumors (OR 0.5, 95%CI 0.3-0.9). We observed interactions between CRP rs1800947 and BMI and family history of CRC in modifying risk of both colon and rectal cancer. Conclusions These data suggest that genetic variation in the CRP gene influences risk of both colon and rectal cancer development. PMID:20949557

Pan-Tropical Analysis of Climate Effects on Seasonal Tree Growth

PubMed Central

Wagner, Fabien; Rossi, Vivien; Aubry-Kientz, Mélaine; Bonal, Damien; Dalitz, Helmut; Gliniars, Robert; Stahl, Clément; Trabucco, Antonio; Hérault, Bruno

2014-01-01

Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent. PMID:24670981

Pan-tropical analysis of climate effects on seasonal tree growth.

PubMed

Wagner, Fabien; Rossi, Vivien; Aubry-Kientz, Mélaine; Bonal, Damien; Dalitz, Helmut; Gliniars, Robert; Stahl, Clément; Trabucco, Antonio; Hérault, Bruno

2014-01-01

Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent.

Mechanical property assessment of tissue-mimicking phantoms using remote palpation and optical read-out for amplitude of vibration and refractive index modulation.

PubMed

Usha Devi, C; Bharat Chandran, R S; Vasu, R Mohan; Sood, Ajay K

2007-01-01

A coherent light beam is used to interrogate the focal region within a tissue-mimicking phantom insonified by an ultrasound transducer. The ultrasound-tagged photons exiting from the object carry with them information on local optical path length fluctuations caused by refractive index variations and medium vibration. Through estimation of the force distribution in the focal region of the ultrasound transducer, and solving the forward elastography problem for amplitude of vibration of tissue particles, we observe that the amplitude is directed along the axis of the transducer. It is shown that the focal region interrogated by photons launched along the transducer axis carries phase fluctuations owing to both refractive index variations and particle vibration, whereas the photons launched perpendicular to the transducer axis carry phase fluctuations arising mainly from the refractive index variations, with only smaller contribution from vibration of particles. Monte-Carlo simulations and experiments done on tissue-mimicking phantoms prove that as the storage modulus of the phantom is increased, the detected modulation depth in autocorrelation is reduced, significantly for axial photons and only marginally for the transverse-directed photons. It is observed that the depth of modulation is reduced to a significantly lower and constant value as the storage modulus of the medium is increased. This constant value is found to be the same for both axial and transverse optical interrogation. This proves that the residual modulation depth is owing to refractive index fluctuations alone, which can be subtracted from the overall measured modulation depth, paving the way for a possible quantitative reconstruction of storage modulus. Moreover, since the transverse-directed photons are not significantly affected by storage modulus variations, for a quantitatively accurate read-out of absorption coefficient variation, the interrogating light should be perpendicular to the focusing ultrasound transducer axis.

Effect of environmental conditions on variation in the sediment-water interface created by complex macrofaunal burrows on a tidal flat

NASA Astrophysics Data System (ADS)

Koo, Bon Joo; Kwon, Kae Kyoung; Hyun, Jung-Ho

2007-11-01

We quantified the increase in the sediment-water interface created by the burrowing activities of the resident macrofaunal community and its variation with respect to the physical conditions of the habitat on a tidal fat. We investigated environmental factors and dimensions of macrofaunal burrows with respect to tidal height and vegetation during spring and summer at three sites. A resin-casting method was used to quantify the dimensions of all burrows at each site. The dimensions of macrofaunal burrows varied both temporally and spatially and the increase in the sediment-water interface reached a maximum of 311%, ranging from 20 to 255% under different habitat conditions. The sediment-water interface depended on the duration of exposure resulting from tidal height, increased temperatures resulting from seasonality, and marsh plant density. Burrows were deeper and more expansive at both higher tidal levels and higher temperatures in summer. Burrow dimensions were sharply reduced with the disappearance of adult macrofauna in areas where the roots of the marsh plant Suaeda japonica were dense. The significance of this study lies in quantifying the burrow dimensions of the entire macrofaunal community, rather than just a single population, and confirming their spatial and temporal variation with respect to physical conditions of the habitat. Environmental factors responsible for variation in burrow dimensions are discussed.

Early age thermal conditioning immediately reduces body temperature of broiler chicks in a tropical environment.

PubMed

De Basilio, V; Requena, F; León, A; Vilariño, M; Picard, M

2003-08-01

Early age thermal conditioning (TC) durably improves resistance of broilers to heat stress and reduces body temperature (Tb). Three experiments on broiler chicks were conducted to evaluate the effects of TC at 5 d of age on Tb variation measured by thermometer between 4 and 7 d of age, under a tropical environment. Because manipulation of chickens to measure Tb with a thermometer may increase Tb, a preliminary experiment on 13 3-to-4-wk-old male broilers compared Tb measured by telemetry to Tb measured in the terminal colon during three successive periods at 22, 33, and 22 degrees C. During heat exposure, Tb rapidly increased by 0.9 degrees C and plateaued over 24 h. During the last period, seven of the broilers rapidly reduced Tb to a plateau lower than the initial Tb, although six broilers exhibited more variable Tb. Measurement by thermometer underestimated on average core Tb by 0.28 degrees C at 22 degrees C and by 0.57 degrees C at 33 degrees C, whereas Tb recorded by telemetry was not affected by manipulation of the chickens. TC reduced Tb 24 h later in the three experiments. Compared to unexposed control chicks (N), 12 h of TC at 40 degrees C did not significantly reduce Tb at 7 d of age, although 24 h did. TC at 38 and 40 degrees C over 24 h significantly reduced Tb variation from 4 to 7 d of age compared to N chicks, whereas 36 degrees C did not. Withdrawing feed from the chicks for 2 h prior to measurement did not significantly reduce Tb at 4 and 7 d of age, but Tb reduction due to TC was greater in fed chicks (0.28 degrees C) than in chicks without feed (0.05 degrees C). Early age thermal conditioning at 38 to 40 degrees C at 5 d of age for 24 h reduced body temperature of 7-d-old male broilers.

Marker-dependent associations among oxidative stress, growth and survival during early life in a wild mammal

PubMed Central

Selman, Colin; Blount, Jonathan D.; Pilkington, Jill G.; Watt, Kathryn A.; Pemberton, Josephine M.; Reid, Jane M.

2016-01-01

Oxidative stress (OS) is hypothesized to be a key physiological mechanism mediating life-history trade-offs, but evidence from wild populations experiencing natural environmental variation is limited. We tested the hypotheses that increased early life growth rate increases OS, and that increased OS reduces first-winter survival, in wild Soay sheep (Ovis aries) lambs. We measured growth rate and first-winter survival for four consecutive cohorts, and measured two markers of oxidative damage (malondialdehyde (MDA), protein carbonyls (PC)) and two markers of antioxidant (AOX) protection (total AOX capacity (TAC), superoxide dismutase (SOD)) from blood samples. Faster lamb growth was weakly associated with increased MDA, but not associated with variation in the other three markers. Lambs with higher SOD activity were more likely to survive their first winter, as were male but not female lambs with lower PC concentrations. Survival did not vary with MDA or total TAC. Key predictions relating OS to growth and survival were therefore supported in some OS markers, but not others. This suggests that different markers capture different aspects of the complex relationships between individual oxidative state, physiology and fitness, and that overarching hypotheses relating OS to life-history variation cannot be supported or refuted by studying individual markers. PMID:27733545

On prediction of crack in different orientations in pipe using frequency based approach

NASA Astrophysics Data System (ADS)

Naniwadekar, M. R.; Naik, S. S.; Maiti, S. K.

2008-04-01

A technique based on measurement of change in natural frequencies and modeling of crack by rotational spring is employed to detect a crack with straight front in different orientations in a section of straight horizontal steel hollow pipe (outer diameter 0.0378 m and inner diameter 0.0278 m). Crack orientations in the range 0-60° with the vertical have been examined and sizes/depths in the range 1-4 mm through the wall of thickness 5 mm have been studied. Variation of rotational spring stiffness with crack size and orientation has been obtained experimentally by deflection and vibration methods. The spring stiffness reduces as expected, with an increase in crack size; it increases with an increase in the crack orientation angle. The crack location has been predicted with a maximum error of 7.29%. The sensitivity of the method for prediction of crack location on variations in experimental data has been examined by changing the difference between the frequencies of pipes with and without crack by ±10%. The method is found to be very robust; the maximum variation in location is 2.68%, which is much less than the change in frequency difference introduced.

Hybridization increases invasive knotweed success

PubMed Central

Parepa, Madalin; Fischer, Markus; Krebs, Christine; Bossdorf, Oliver

2014-01-01

Hybridization is one of the fundamental mechanisms by which rapid evolution can occur in exotic species. If hybrids show increased vigour, this could significantly contribute to invasion success. Here, we compared the success of the two invasive knotweeds, Fallopia japonica and F. sachalinensis, and their hybrid, F. × bohemica, in competing against experimental communities of native plants. Using plant material from multiple clones of each taxon collected across a latitudinal gradient in Central Europe, we found that knotweed hybrids performed significantly better in competition with a native community and that they more strongly reduced the growth of the native plants. One of the parental species, F. sachalinensis, regenerated significantly less well from rhizomes, and this difference disappeared if activated carbon was added to the substrate, which suggests allelopathic inhibition of F. sachalinensis regeneration by native plants. We found substantial within-taxon variation in competitive success in all knotweed taxa, but variation was generally greatest in the hybrid. Interestingly, there was also significant variation within the genetically uniform F. japonica, possibly reflecting epigenetic differences. Our study shows that invasive knotweed hybrids are indeed more competitive than their parents and that hybridization increased the invasiveness of the exotic knotweed complex. PMID:24665343

How will provider-focused payment reform impact geographic variation in Medicare spending?

PubMed

Auerbach, David; Mehrotra, Ateev; Hussey, Peter; Huckfeldt, Peter J; Alpert, Abby; Lau, Christopher; Shier, Victoria

2015-06-01

The Institute of Medicine has recently argued against a value index as a mechanism to address geographic variation in spending and instead promoted payment reform targeted at individual providers. It is unknown whether such provider-focused payment reform reduces geographic variation in spending. We estimated the potential impact of 3 Medicare provider-focused payment policies-pay-for-performance, bundled payment, and accountable care organizations-on geographic variation in Medicare spending across Hospital Referral Regions (HRRs). We compared geographic variation in spending, measured using the coefficient of variation (CV) across HRRs, between the baseline case and a simulation of each of the 3 policies. Policy simulation based on 2008 national Medicare data combined with other publicly available data. Compared with the baseline (CV, 0.171), neither pay-for-performance nor accountable care organizations would change geographic variation in spending (CV, 0.171), while bundled payment would modestly reduce geographic variation (CV, 0.165). In our models, the bundled payment for inpatient and post acute care services in Medicare would modestly reduce geographic variation in spending, but neither accountable care organizations nor pay-for-performance appear to have an impact.

Is lowering reducing sugars concentration in French fries an effective measure to reduce acrylamide concentration in food service establishments?

PubMed

Sanny, M; Jinap, S; Bakker, E J; van Boekel, M A J S; Luning, P A

2012-12-01

The objective of this study was to obtain insight into the actual effectiveness of lowering reducing sugars concentration in par-fried potato strips on the concentration and variation of acrylamide in French fries prepared in real-life situations in food service establishments. Acrylamide, frying time, frying temperature, and reducing sugars were measured and characteristics of fryers were recorded. Data showed that the use of par-fried potato strips with lower concentrations of reducing sugars than the commonly used potato strips was an effective measure to reduce acrylamide concentrations in French fries prepared under standardised frying conditions. However, there was still large variation in the acrylamide concentrations in French fries, although the variation in reducing sugars concentrations in low and normal types of par-fried potato strips was very small and the frying conditions were similar. Factors that could affect the temperature-time profile of frying oil were discussed, such as setting a lower frying temperature at the end than at the start of frying, product/oil ratio and thawing practice. These need to be controlled in daily practice to reduce variation in acrylamide. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of counter-pulsation control of a pulsatile left ventricular assist device on working load variations of the native heart.

PubMed

Choi, Seong Wook; Nam, Kyoung Won; Lim, Ki Moo; Shim, Eun Bo; Won, Yong Soon; Woo, Heung Myong; Kwak, Ho Hyun; Noh, Mi Ryoung; Kim, In Young; Park, Sung Min

2014-04-03

When using a pulsatile left ventricular assist device (LVAD), it is important to reduce the cardiac load variations of the native heart because severe cardiac load variations can induce ventricular arrhythmia. In this study, we investigated the effect of counter-pulsation control of the LVAD on the reduction of cardiac load variation. A ventricular electrocardiogram-based counter-pulsation control algorithm for a LVAD was implemented, and the effects of counter-pulsation control of the LVAD on the reduction of the working load variations of the left ventricle were determined in three animal experiments. Deviations of the working load of the left ventricle were reduced by 51.3%, 67.9%, and 71.5% in each case, and the beat-to-beat variation rates in the working load were reduced by 84.8%, 82.7%, and 88.2% in each ease after counter-pulsation control. There were 3 to 12 premature ventricle contractions (PVCs) before counter-pulsation control, but no PVCs were observed during counter-pulsation control. Counter-pulsation control of the pulsatile LVAD can reduce severe cardiac load variations, but the average working load is not markedly affected by application of counter-pulsation control because it is also influenced by temporary cardiac outflow variations. We believe that counter-pulsation control of the LVAD can improve the long-term safety of heart failure patients equipped with LVADs.

Influence of interface inhomogeneities in thin-film Schottky diodes

NASA Astrophysics Data System (ADS)

Wilson, Joshua; Zhang, Jiawei; Li, Yunpeng; Wang, Yiming; Xin, Qian; Song, Aimin

2017-11-01

The scalability of thin-film transistors has been well documented, but there have been very few investigations into the effects of device scalability in Schottky diodes. Indium-gallium-zinc-oxide (IGZO) Schottky diodes were fabricated with IGZO thicknesses of 50, 150, and 250 nm. Despite the same IGZO-Pt interface and Schottky barrier being formed in all devices, reducing the IGZO thickness caused a dramatic deterioration of the current-voltage characteristics, most notably increasing the reverse current by nearly five orders of magnitude. Furthermore, the forward characteristics display an increase in the ideality factor and a reduction in the barrier height. The origins of this phenomenon have been elucidated using device simulations. First, when the semiconductor layer is fully depleted, the electric field increases with the reducing thickness, leading to an increased diffusion current. However, the effects of diffusion only offer a small contribution to the huge variations in reverse current seen in the experiments. To fully explain this effect, the role of inhomogeneities in the Schottky barrier height has been considered. Contributions from lower barrier regions (LBRs) are found to dominate the reverse current. The conduction band minimum below these LBRs is strongly dependent upon thickness and bias, leading to reverse current variations as large as several orders of magnitude. Finally, it is demonstrated that the thickness dependence of the reverse current is exacerbated as the magnitude of the inhomogeneities is increased and alleviated in the limit where the LBRs are large enough not to be influenced by the adjacent higher barrier regions.

Locomotor Behavior of Chickens Anticipating Incline Walking

PubMed Central

LeBlanc, Chantal; Tobalske, Bret; Szkotnicki, Bill; Harlander-Matauschek, Alexandra

2018-01-01

Keel bone damage (KBD) is prevalent in hens raised for egg production, and ramps between different tiers in aviaries have potential to reduce the frequency of falls resulting in KBD. Effective use of ramps requires modulation of locomotion in anticipation of the incline. Inadequate adaptive locomotion may be one explanation why domestic layer hens (Gallus gallus domesticus) exhibit high rates of KBD. To improve understanding of the capacity of hens to modulate their locomotion in anticipation of climbing, we measured the effects of incline angle upon the mechanics of the preparatory step before ascending a ramp. Because the energetic challenge of climbing increases with slope, we predicted that as angle of incline increased, birds during foot contact with the ground before starting to climb would increase their peak force and duration of contact and reduce variation in center of pressure (COP) under their foot. We tested 20 female domestic chickens on ramp inclines at slopes of +0°, +40°, and +70° when birds were 17, 21, 26, 31, and 36 weeks of age. There were significantly higher vertical peak ground reaction forces in preparation at the steepest slope, and ground contact time increased significantly with each increase in ramp angle. Effects upon variation in COP were not apparent; likewise, effects of limb length, age, body mass were not significant. Our results reveal that domestic chickens are capable of modulating their locomotion in response to incline angle. PMID:29376060

Effect of reducing groundwater on the retardation of redox-sensitive radionuclides

PubMed Central

Hu, QH; Zavarin, M; Rose, TP

2008-01-01

Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions were designed to simulate subsurface conditions at the Nevada Test Site (NTS), where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing) conditions, radionuclide distribution coefficients varied with the mineralogic composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for 99Tc (from 1.22 at oxidizing to 378 mL/g at mildly reducing conditions) and 237Np (an increase from 4.6 to 930 mL/g) in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for 99Tc, which tends to be mobile under oxidizing conditions. A review of the literature suggests that iodine sorption should decrease under reducing conditions when I- is the predominant species; this was not consistently observed in batch tests. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI) reduction to U(IV). Sorption of Pu was not affected by the decreasing Eh conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH)4. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides 99Tc and 237Np, which are commonly identified as long-term dose contributors in the risk assessment in various radionuclide environmental contamination scenarios. The implications for increased sorption of 99Tc and 237Np to devitrified tuff under reducing conditions are significant as the fractured devitrified tuff serves as important water flow path at the NTS and the horizon for a proposed repository to store high-level nuclear waste at Yucca Mountain. PMID:19077277

Postcopulatory Sexual Selection Results in Spermatozoa with More Uniform Head and Flagellum Sizes in Rodents

PubMed Central

Varea-Sánchez, María; Gómez Montoto, Laura; Tourmente, Maximiliano; Roldan, Eduardo R. S.

2014-01-01

Interspecific comparative studies have shown that, in most taxa, postcopulatory sexual selection (PCSS) in the form of sperm competition drives the evolution of longer and faster swimming sperm. Work on passserine birds has revealed that PCSS also reduces variation in sperm size between males at the intraspecific level. However, the influence of PCSS upon intra-male sperm size diversity is poorly understood, since the few studies carried out to date in birds have yielded contradictory results. In mammals, PCSS increases sperm size but there is little information on the effects of this selective force on variations in sperm size and shape. Here, we test whether sperm competition associates with a reduction in the degree of variation of sperm dimensions in rodents. We found that as sperm competition levels increase males produce sperm that are more similar in both the size of the head and the size of the flagellum. On the other hand, whereas with increasing levels of sperm competition there is less variation in head length in relation to head width (ratio CV head length/CV head width), there is no relation between variation in head and flagellum sizes (ratio CV head length/CV flagellum length). Thus, it appears that, in addition to a selection for longer sperm, sperm competition may select more uniform sperm heads and flagella, which together may enhance swimming velocity. Overall, sperm competition seems to drive sperm components towards an optimum design that may affect sperm performance which, in turn, will be crucial for successful fertilization. PMID:25243923

Modifiers: Increasing Richness and Nuance of Design Pattern Languages

NASA Astrophysics Data System (ADS)

Kolfschoten, Gwendolyn L.; Briggs, Robert O.; Lukosch, Stephan

One of the challenges when establishing and maintaining a pattern language is to balance richness with simplicity. On the one hand, designers need a variety of useful design patterns to increase the speed of their design efforts and to reduce design risk. On the other hand, the greater the variety of design patterns in a language, the higher the cognitive load to remember and select among them. One solution to this problem is the concept of a modifier design pattern, a design pattern for pattern languages. A modifier pattern is a named, documented variation that can be applied to some set of other design patterns. They create similar, useful changes and refinements to the solutions derived from any pattern to which they are applied. The modifier concept, described in this paper emerged in a relatively new design pattern language for collaborative work practices in which the design patterns are called thinkLets. When analyzing the thinkLet pattern language, we found that many of the patterns we knew were variations and refinements of other patterns. However, we also found patterns in these variations; we found variations that could be applied to different patterns, with similar effects. We document these variations as modifiers. In this paper, we introduce the concept of modifier design patterns and illustrate the use of modifiers with two case studies.

Increasing Crop Diversity Mitigates Weather Variations and Improves Yield Stability

PubMed Central

Gaudin, Amélie C. M.; Tolhurst, Tor N.; Ker, Alan P.; Janovicek, Ken; Tortora, Cristina; Martin, Ralph C.; Deen, William

2015-01-01

Cropping sequence diversification provides a systems approach to reduce yield variations and improve resilience to multiple environmental stresses. Yield advantages of more diverse crop rotations and their synergistic effects with reduced tillage are well documented, but few studies have quantified the impact of these management practices on yields and their stability when soil moisture is limiting or in excess. Using yield and weather data obtained from a 31-year long term rotation and tillage trial in Ontario, we tested whether crop rotation diversity is associated with greater yield stability when abnormal weather conditions occur. We used parametric and non-parametric approaches to quantify the impact of rotation diversity (monocrop, 2-crops, 3-crops without or with one or two legume cover crops) and tillage (conventional or reduced tillage) on yield probabilities and the benefits of crop diversity under different soil moisture and temperature scenarios. Although the magnitude of rotation benefits varied with crops, weather patterns and tillage, yield stability significantly increased when corn and soybean were integrated into more diverse rotations. Introducing small grains into short corn-soybean rotation was enough to provide substantial benefits on long-term soybean yields and their stability while the effects on corn were mostly associated with the temporal niche provided by small grains for underseeded red clover or alfalfa. Crop diversification strategies increased the probability of harnessing favorable growing conditions while decreasing the risk of crop failure. In hot and dry years, diversification of corn-soybean rotations and reduced tillage increased yield by 7% and 22% for corn and soybean respectively. Given the additional advantages associated with cropping system diversification, such a strategy provides a more comprehensive approach to lowering yield variability and improving the resilience of cropping systems to multiple environmental stresses. This could help to sustain future yield levels in challenging production environments. PMID:25658914

Fecundity compensation and tolerance to a sterilizing pathogen in Daphnia.

PubMed

Vale, P F; Little, T J

2012-09-01

Hosts are armed with several lines of defence in the battle against parasites: they may prevent the establishment of infection, reduce parasite growth once infected or persevere through mechanisms that reduce the damage caused by infection, called tolerance. Studies on tolerance in animals have focused on mortality, and sterility tolerance has not been investigated experimentally. Here, we tested for genetic variation in the multiple steps of defence when the invertebrate Daphnia magna is infected with the sterilizing bacterial pathogen Pasteuria ramosa: anti-infection resistance, anti-growth resistance and the ability to tolerate sterilization once infected. When exposed to nine doses of a genetically diverse pathogen inoculum, six host genotypes varied in their average susceptibility to infection and in their parasite loads once infected. How host fecundity changed with increasing parasite loads did not vary between genotypes, indicating that there was no genetic variation for this measure of fecundity tolerance. However, genotypes differed in their level of fecundity compensation under infection, and we discuss how, by increasing host fitness without targeting parasite densities, fecundity compensation is consistent with the functional definition of tolerance. Such infection-induced life-history shifts are not traditionally considered to be part of the immune response, but may crucially reduce harm (in terms of fitness loss) caused by disease, and are a distinct source of selection on pathogens. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Comparison of three commercially available ektacytometers with different shearing geometries.

PubMed

Baskurt, Oguz K; Hardeman, M R; Uyuklu, Mehmet; Ulker, Pinar; Cengiz, Melike; Nemeth, Norbert; Shin, Sehyun; Alexy, Tamas; Meiselman, Herbert J

2009-01-01

In December 2008, the International Society for Clinical Hemorheology organized a workshop to evaluate and compare three ektacytometer instruments for measuring deformability of red blood cells (RBC): LORCA (Laser-assisted Optical Rotational Cell Analyzer, RR Mechatronics, Hoorn, The Netherlands), Rheodyn SSD (Myrenne GmbH, Roetgen, Germany) and RheoScan-D (RheoMeditech, Seoul, Korea). Intra-assay reproducibility and biological variation were determined using normal RBC, and cells with reduced deformability (i.e., 0.001-0.02% glutaradehyde (GA), 48 degrees C heat treatment) were employed as either the only RBC present or as a sub-population. Standardized difference values were used as measure of the power to detect differences between normal and treated cells. Salient results include: (1) All instruments had intra-assay variations below 5% for shear stress (SS)>1 Pa but a sharp increase was found for Rheodyn SSD and RheoScan-D at lower SS; (2) Biological variation was similar and markedly increased for SS<3-5 Pa; (3) All instruments detected GA-treated RBC with maximal power at 1-3 Pa, the presence of 10% or 40% GA-modified cells, and the effects of heat treatment. It is concluded that the LORCA, Rheodyn SSD and RheoScan-D all have acceptable precision and power for detecting reduced RBC deformability due to GA treatment or heat treatment, and that the SS range selected for the measurement of deformability is an important determinant of an instrument's power.

Characterising and correcting batch variation in an automated direct infusion mass spectrometry (DIMS) metabolomics workflow.

PubMed

Kirwan, J A; Broadhurst, D I; Davidson, R L; Viant, M R

2013-06-01

Direct infusion mass spectrometry (DIMS)-based untargeted metabolomics measures many hundreds of metabolites in a single experiment. While every effort is made to reduce within-experiment analytical variation in untargeted metabolomics, unavoidable sources of measurement error are introduced. This is particularly true for large-scale multi-batch experiments, necessitating the development of robust workflows that minimise batch-to-batch variation. Here, we conducted a purpose-designed, eight-batch DIMS metabolomics study using nanoelectrospray (nESI) Fourier transform ion cyclotron resonance mass spectrometric analyses of mammalian heart extracts. First, we characterised the intrinsic analytical variation of this approach to determine whether our existing workflows are fit for purpose when applied to a multi-batch investigation. Batch-to-batch variation was readily observed across the 7-day experiment, both in terms of its absolute measurement using quality control (QC) and biological replicate samples, as well as its adverse impact on our ability to discover significant metabolic information within the data. Subsequently, we developed and implemented a computational workflow that includes total-ion-current filtering, QC-robust spline batch correction and spectral cleaning, and provide conclusive evidence that this workflow reduces analytical variation and increases the proportion of significant peaks. We report an overall analytical precision of 15.9%, measured as the median relative standard deviation (RSD) for the technical replicates of the biological samples, across eight batches and 7 days of measurements. When compared against the FDA guidelines for biomarker studies, which specify an RSD of <20% as an acceptable level of precision, we conclude that our new workflows are fit for purpose for large-scale, high-throughput nESI DIMS metabolomics studies.

A heuristic model on the role of plasticity in adaptive evolution: plasticity increases adaptation, population viability and genetic variation.

PubMed

Gomez-Mestre, Ivan; Jovani, Roger

2013-11-22

An ongoing new synthesis in evolutionary theory is expanding our view of the sources of heritable variation beyond point mutations of fixed phenotypic effects to include environmentally sensitive changes in gene regulation. This expansion of the paradigm is necessary given ample evidence for a heritable ability to alter gene expression in response to environmental cues. In consequence, single genotypes are often capable of adaptively expressing different phenotypes in different environments, i.e. are adaptively plastic. We present an individual-based heuristic model to compare the adaptive dynamics of populations composed of plastic or non-plastic genotypes under a wide range of scenarios where we modify environmental variation, mutation rate and costs of plasticity. The model shows that adaptive plasticity contributes to the maintenance of genetic variation within populations, reduces bottlenecks when facing rapid environmental changes and confers an overall faster rate of adaptation. In fluctuating environments, plasticity is favoured by selection and maintained in the population. However, if the environment stabilizes and costs of plasticity are high, plasticity is reduced by selection, leading to genetic assimilation, which could result in species diversification. More broadly, our model shows that adaptive plasticity is a common consequence of selection under environmental heterogeneity, and hence a potentially common phenomenon in nature. Thus, taking adaptive plasticity into account substantially extends our view of adaptive evolution.

Neighborhood influences on the association between maternal age and birthweight: a multilevel investigation of age-related disparities in health.

PubMed

Cerdá, Magdalena; Buka, Stephen L; Rich-Edwards, Janet W

2008-05-01

It was hypothesized that the relationship between maternal age and infant birthweight varies significantly across neighborhoods and that such variation can be predicted by neighborhood characteristics. We analyzed 229,613 singleton births of mothers aged 20-45 years from Chicago, USA in 1997-2002. Random coefficient models were used to estimate the between-neighborhood variation in age-birthweight slopes, and both intercepts- and-slopes-as-outcomes models were used to evaluate area-level predictors of such variation. The crude maternal age-birthweight slopes for neighborhoods ranged from a decrease of 17 g to an increase of 10 g per year of maternal age. Adjustment for individual-level covariates reduced but did not eliminate this between-neighborhood variation. Concentrated poverty was a significant neighborhood-level predictor of the age-birthweight slope, explaining 44.4% of the between-neighborhood variation in slopes. Neighborhoods of higher economic disadvantage showed a more negative age-birthweight slope. The findings support the hypothesis that the relationship between maternal age and birthweight varies between neighborhoods. Indicators of neighborhood disadvantage help to explain such differences.

Effects of river flow regime on cottonwood leaf litter dynamics in semi-arid northwestern Colorado

USGS Publications Warehouse

Andersen, D.C.; Nelson, S.M.

2003-01-01

We compared production and breakdown of Fremont cottonwood (Populus deltoides wislizenii) leaf litter at matched floodplain sites on the regulated Green River and unregulated Yampa River in semi-arid northwestern Colorado. Litter production under trees was similar at sites in 1999 (250 g/m2, oven-dry) but lower in 2000 (215 and 130 g/m2), a drought year that also featured an outbreak of defoliating beetles at the Yampa River site. Our production values were similar to the few others reported for riparian forests within semi-arid or arid areas. Leaf litter in portions of the floodplain not inundated during the spring flood lost organic matter at the same rate as leaves placed in upland sites in 1998 and 2000: 35 to 50% of organic matter during an approximately 160-day spring and summer period. Inundated litter lost 55 to 90% of its organic matter during the same period. Organic matter loss from inundated leaves increased with duration of inundation and with deposition of fine sediment. Pooled across locations, leafpack data suggested that nitrogen concentration (mg N/kg organic matter) increased until about 65% of the initial organic matter was lost. This increase likely reflected the buildup of microbial decomposer populations. The role of insects and other macroinvertebrates in litter breakdown apparently was minor at both sites. Large spatial and temporal variation in litter dynamics in aridland floodplain settings is ensured by microtopographic variation in the alluvial surface coupled with year-to-year variation associated with most natural flood regimes. Factors reducing flood flow frequency or magnitude will reduce overall breakdown rates on the floodplain towards those found in drier upland environments.

Large-Scale Variation in Combined Impacts of Canopy Loss and Disturbance on Community Structure and Ecosystem Functioning

PubMed Central

Crowe, Tasman P.; Cusson, Mathieu; Bulleri, Fabio; Davoult, Dominique; Arenas, Francisco; Aspden, Rebecca; Benedetti-Cecchi, Lisandro; Bevilacqua, Stanislao; Davidson, Irvine; Defew, Emma; Fraschetti, Simonetta; Golléty, Claire; Griffin, John N.; Herkül, Kristjan; Kotta, Jonne; Migné, Aline; Molis, Markus; Nicol, Sophie K.; Noël, Laure M-L J.; Pinto, Isabel Sousa; Valdivia, Nelson; Vaselli, Stefano; Jenkins, Stuart R.

2013-01-01

Ecosystems are under pressure from multiple human disturbances whose impact may vary depending on environmental context. We experimentally evaluated variation in the separate and combined effects of the loss of a key functional group (canopy algae) and physical disturbance on rocky shore ecosystems at nine locations across Europe. Multivariate community structure was initially affected (during the first three to six months) at six locations but after 18 months, effects were apparent at only three. Loss of canopy caused increases in cover of non-canopy algae in the three locations in southern Europe and decreases in some northern locations. Measures of ecosystem functioning (community respiration, gross primary productivity, net primary productivity) were affected by loss of canopy at five of the six locations for which data were available. Short-term effects on community respiration were widespread, but effects were rare after 18 months. Functional changes corresponded with changes in community structure and/or species richness at most locations and times sampled, but no single aspect of biodiversity was an effective predictor of longer-term functional changes. Most ecosystems studied were able to compensate in functional terms for impacts caused by indiscriminate physical disturbance. The only consistent effect of disturbance was to increase cover of non-canopy species. Loss of canopy algae temporarily reduced community resistance to disturbance at only two locations and at two locations actually increased resistance. Resistance to disturbance-induced changes in gross primary productivity was reduced by loss of canopy algae at four locations. Location-specific variation in the effects of the same stressors argues for flexible frameworks for the management of marine environments. These results also highlight the need to analyse how species loss and other stressors combine and interact in different environmental contexts. PMID:23799082

Coding Response to a Case-Mix Measurement System Based on Multiple Diagnoses

PubMed Central

Preyra, Colin

2004-01-01

Objective To examine the hospital coding response to a payment model using a case-mix measurement system based on multiple diagnoses and the resulting impact on a hospital cost model. Data Sources Financial, clinical, and supplementary data for all Ontario short stay hospitals from years 1997 to 2002. Study Design Disaggregated trends in hospital case-mix growth are examined for five years following the adoption of an inpatient classification system making extensive use of combinations of secondary diagnoses. Hospital case mix is decomposed into base and complexity components. The longitudinal effects of coding variation on a standard hospital payment model are examined in terms of payment accuracy and impact on adjustment factors. Principal Findings Introduction of the refined case-mix system provided incentives for hospitals to increase reporting of secondary diagnoses and resulted in growth in highest complexity cases that were not matched by increased resource use over time. Despite a pronounced coding response on the part of hospitals, the increase in measured complexity and case mix did not reduce the unexplained variation in hospital unit cost nor did it reduce the reliance on the teaching adjustment factor, a potential proxy for case mix. The main implication was changes in the size and distribution of predicted hospital operating costs. Conclusions Jurisdictions introducing extensive refinements to standard diagnostic related group (DRG)-type payment systems should consider the effects of induced changes to hospital coding practices. Assessing model performance should include analysis of the robustness of classification systems to hospital-level variation in coding practices. Unanticipated coding effects imply that case-mix models hypothesized to perform well ex ante may not meet expectations ex post. PMID:15230940

Large-scale variation in combined impacts of canopy loss and disturbance on community structure and ecosystem functioning.

PubMed

Crowe, Tasman P; Cusson, Mathieu; Bulleri, Fabio; Davoult, Dominique; Arenas, Francisco; Aspden, Rebecca; Benedetti-Cecchi, Lisandro; Bevilacqua, Stanislao; Davidson, Irvine; Defew, Emma; Fraschetti, Simonetta; Golléty, Claire; Griffin, John N; Herkül, Kristjan; Kotta, Jonne; Migné, Aline; Molis, Markus; Nicol, Sophie K; Noël, Laure M-L J; Pinto, Isabel Sousa; Valdivia, Nelson; Vaselli, Stefano; Jenkins, Stuart R

2013-01-01

Ecosystems are under pressure from multiple human disturbances whose impact may vary depending on environmental context. We experimentally evaluated variation in the separate and combined effects of the loss of a key functional group (canopy algae) and physical disturbance on rocky shore ecosystems at nine locations across Europe. Multivariate community structure was initially affected (during the first three to six months) at six locations but after 18 months, effects were apparent at only three. Loss of canopy caused increases in cover of non-canopy algae in the three locations in southern Europe and decreases in some northern locations. Measures of ecosystem functioning (community respiration, gross primary productivity, net primary productivity) were affected by loss of canopy at five of the six locations for which data were available. Short-term effects on community respiration were widespread, but effects were rare after 18 months. Functional changes corresponded with changes in community structure and/or species richness at most locations and times sampled, but no single aspect of biodiversity was an effective predictor of longer-term functional changes. Most ecosystems studied were able to compensate in functional terms for impacts caused by indiscriminate physical disturbance. The only consistent effect of disturbance was to increase cover of non-canopy species. Loss of canopy algae temporarily reduced community resistance to disturbance at only two locations and at two locations actually increased resistance. Resistance to disturbance-induced changes in gross primary productivity was reduced by loss of canopy algae at four locations. Location-specific variation in the effects of the same stressors argues for flexible frameworks for the management of marine environments. These results also highlight the need to analyse how species loss and other stressors combine and interact in different environmental contexts.

Modeling Systematic Change in Stopover Duration Does Not Improve Bias in Trends Estimated from Migration Counts.

PubMed

Crewe, Tara L; Taylor, Philip D; Lepage, Denis

2015-01-01

The use of counts of unmarked migrating animals to monitor long term population trends assumes independence of daily counts and a constant rate of detection. However, migratory stopovers often last days or weeks, violating the assumption of count independence. Further, a systematic change in stopover duration will result in a change in the probability of detecting individuals once, but also in the probability of detecting individuals on more than one sampling occasion. We tested how variation in stopover duration influenced accuracy and precision of population trends by simulating migration count data with known constant rate of population change and by allowing daily probability of survival (an index of stopover duration) to remain constant, or to vary randomly, cyclically, or increase linearly over time by various levels. Using simulated datasets with a systematic increase in stopover duration, we also tested whether any resulting bias in population trend could be reduced by modeling the underlying source of variation in detection, or by subsampling data to every three or five days to reduce the incidence of recounting. Mean bias in population trend did not differ significantly from zero when stopover duration remained constant or varied randomly over time, but bias and the detection of false trends increased significantly with a systematic increase in stopover duration. Importantly, an increase in stopover duration over time resulted in a compounding effect on counts due to the increased probability of detection and of recounting on subsequent sampling occasions. Under this scenario, bias in population trend could not be modeled using a covariate for stopover duration alone. Rather, to improve inference drawn about long term population change using counts of unmarked migrants, analyses must include a covariate for stopover duration, as well as incorporate sampling modifications (e.g., subsampling) to reduce the probability that individuals will be detected on more than one occasion.

Effects of ambient oxygen and size-selective mortality on growth and maturation in guppies

PubMed Central

Diaz Pauli, Beatriz; Kolding, Jeppe; Jeyakanth, Geetha

2017-01-01

Abstract Growth, onset of maturity and investment in reproduction are key traits for understanding variation in life-history strategies. Many environmental factors affect variation in these traits, but for fish, hypoxia and size-dependent mortality have become increasingly important because of human activities, such as increased nutrient enrichment (eutrophication), climate warming and selective fishing. Here, we study experimentally the effect of oxygen availability on maturation and growth in guppies (Poecilia reticulata) from two different selected lines, one subjected to positive and the other negative size-dependent fishing. This is the first study to assess the effects of both reduced ambient oxygen and size-dependent mortality in fish. We show that reduced ambient oxygen led to stunting, early maturation and high reproductive investment. Likewise, lineages that had been exposed to high mortality of larger-sized individuals displayed earlier maturation at smaller size, greater investment in reproduction and faster growth. These life-history changes were particularly evident for males. The widely reported trends towards earlier maturation in wild fish populations are often interpreted as resulting from size-selective fishing. Our results highlight that reduced ambient oxygen, which has received little experimental investigation to date, can lead to similar phenotypic changes. Thus, changes in ambient oxygen levels can be a confounding factor that occurs in parallel with fishing, complicating the causal interpretation of changes in life-history traits. We believe that better disentangling of the effects of these two extrinsic factors, which increasingly affect many freshwater and marine ecosystems, is important for making more informed management decisions. PMID:28361001

Controlling for anthropogenically induced atmospheric variation in stable carbon isotope studies

USGS Publications Warehouse

Long, E.S.; Sweitzer, R.A.; Diefenbach, D.R.; Ben-David, M.

2005-01-01

Increased use of stable isotope analysis to examine food-web dynamics, migration, transfer of nutrients, and behavior will likely result in expansion of stable isotope studies investigating human-induced global changes. Recent elevation of atmospheric CO2 concentration, related primarily to fossil fuel combustion, has reduced atmospheric CO2 ??13C (13C/12C), and this change in isotopic baseline has, in turn, reduced plant and animal tissue ??13C of terrestrial and aquatic organisms. Such depletion in CO2 ??13C and its effects on tissue ??13C may introduce bias into ??13C investigations, and if this variation is not controlled, may confound interpretation of results obtained from tissue samples collected over a temporal span. To control for this source of variation, we used a high-precision record of atmospheric CO2 ??13C from ice cores and direct atmospheric measurements to model modern change in CO2 ??13C. From this model, we estimated a correction factor that controls for atmospheric change; this correction reduces bias associated with changes in atmospheric isotopic baseline and facilitates comparison of tissue ??13C collected over multiple years. To exemplify the importance of accounting for atmospheric CO2 ??13C depletion, we applied the correction to a dataset of collagen ??13C obtained from mountain lion (Puma concolor) bone samples collected in California between 1893 and 1995. Before correction, in three of four ecoregions collagen ??13C decreased significantly concurrent with depletion of atmospheric CO2 ??13C (n ??? 32, P ??? 0.01). Application of the correction to collagen ??13C data removed trends from regions demonstrating significant declines, and measurement error associated with the correction did not add substantial variation to adjusted estimates. Controlling for long-term atmospheric variation and correcting tissue samples for changes in isotopic baseline facilitate analysis of samples that span a large temporal range. ?? Springer-Verlag 2005.

Joystick With Cable Springs Offers Better Feel

NASA Technical Reports Server (NTRS)

Kerley, James; Ecklund, Wayne

1992-01-01

Improved joystick allows motion in 6 degrees of freedom, biased toward central position and orientation by 16 segments of cable serving as springs. Improvement in feel and control results from nonlinear compliance of cable-spring assembly. Nonlinear variations accommodate natural reactions of hand and brain. Operator functions as part of feedback control loop. More comfortable, increases ability to exert control and reduces fatigue.

Avoiding Assessment Anarchy. Quality Test Administration Strategies: Communicate Expectations, Reduce Variation, Increase Quality, Improve Relationships, Reward Excellence, Recognize Success.

ERIC Educational Resources Information Center

Matter, M. Kevin

This paper presents strategies that address the needs of the school district assessment office for standardized procedures to support reliable and efficient test processing and reporting and that meet the needs of school staff for test administration guidelines. The key to test administration and processing quality is a knowledgeable test…

Biomechanical pulping with Phlebiopsis gigantea reduced energy consumption and increased paper strength : [summary

Treesearch

Chad J. Behrendt; Robert A. Blanchette; Masood Akhtar; Scott Enebak; Sara Iverson; Diane Williams

2000-01-01

Biomechanical pulping of whole logs pretreated with Phlebiopsis gigantea was investigated in several studies using loblolly and red pine. Results from these studies showed P. gigantea was able to colonize 90 to 100% of the freshly cut logs after 8 weeks, with little variation between replicate treatments. Up to a 59% decrease in resinous wood extractives was observed...

Evolution of three tandem copies of the interleukin-1 receptor-like 1 gene in salmonid fish and their contribution to rainbow trout bacterial cold water disease resistant phenotype

USDA-ARS?s Scientific Manuscript database

Rainbow trout exhibit extensive phenotypic variation in innate disease resistance. Five generations of family based selection has resulted in rainbow trout lines with either increased or reduced survival following exposure to the gram-negative bacterium, Flavobacterium psychrophilum (Fp), the causa...

The Long-Run Impacts of Early Childhood Education: Evidence from a Failed Policy Experiment. NBER Working Paper No. 17085

ERIC Educational Resources Information Center

DeCicca, Philip; Smith, Justin D.

2011-01-01

We investigate short and long-term effects of early childhood education using variation created by a unique policy experiment in British Columbia, Canada. Our findings imply starting Kindergarten one year late substantially reduces the probability of repeating the third grade, and meaningfully increases in tenth grade math and reading scores.…

A Survey of Electronics Obsolescence and Reliability

DTIC Science & Technology

2010-07-01

properties but there are many minor and major variations (e.g. curing schedule) affecting their usage in packaging processes and in reworking. Curing...within them. Electronic obsolescence is increasingly associated with physical characteristics that reduce component and system reliability, both in usage ...semiconductor technologies and of electronic systems, both in usage and in storage. By design, electronics technologies include few reliability margins

A Basic Accounting of Variation in Municipal Solid-Waste Generation at the County Level in Texas, 2006: Groundwork for Applying Metabolic-Rift Theory to Waste Generation

ERIC Educational Resources Information Center

Clement, Matthew Thomas

2009-01-01

Environmental social scientists debate whether or not modern development reduces society's impact on the biosphere. The empirical research informing the discussion has not yet adequately examined the social determinants of municipal solid-waste (MSW) generation, an increasingly relevant issue, both ecologically and sociologically. A primary…

Dietary supplementation with the microalga Galdieria sulphuraria (Rhodophyta) reduces prolonged exercise-induced oxidative stress in rat tissues.

PubMed

Carfagna, Simona; Napolitano, Gaetana; Barone, Daniela; Pinto, Gabriele; Pollio, Antonino; Venditti, Paola

2015-01-01

We studied the effects of ten-day 1% Galdieria sulphuraria dietary supplementation on oxidative damage and metabolic changes elicited by acute exercise (6-hour swimming) determining oxygen consumption, lipid hydroperoxides, protein bound carbonyls in rat tissue (liver, heart, and muscle) homogenates and mitochondria, tissue glutathione peroxidase and glutathione reductase activities, glutathione content, and rates of H2O2 mitochondrial release. Exercise increased oxidative damage in tissues and mitochondria and decreased tissue content of reduced glutathione. Moreover, it increased State 4 and decreased State 3 respiration in tissues and mitochondria. G. sulphuraria supplementation reduced the above exercise-induced variations. Conversely, alga supplementation was not able to modify the exercise-induced increase in mitochondrial release rate of hydrogen peroxide and in liver and heart antioxidant enzyme activities. The alga capacity to reduce lipid oxidative damage without reducing mitochondrial H2O2 release can be due to its high content of C-phycocyanin and glutathione, which are able to scavenge peroxyl radicals and contribute to phospholipid hydroperoxide metabolism, respectively. In conclusion, G. sulphuraria ability to reduce exercise-linked oxidative damage and mitochondrial dysfunction makes it potentially useful even in other conditions leading to oxidative stress, including hyperthyroidism, chronic inflammation, and ischemia/reperfusion.

Dietary Supplementation with the Microalga Galdieria sulphuraria (Rhodophyta) Reduces Prolonged Exercise-Induced Oxidative Stress in Rat Tissues

PubMed Central

Carfagna, Simona; Napolitano, Gaetana; Barone, Daniela; Pinto, Gabriele; Venditti, Paola

2015-01-01

We studied the effects of ten-day 1% Galdieria sulphuraria dietary supplementation on oxidative damage and metabolic changes elicited by acute exercise (6-hour swimming) determining oxygen consumption, lipid hydroperoxides, protein bound carbonyls in rat tissue (liver, heart, and muscle) homogenates and mitochondria, tissue glutathione peroxidase and glutathione reductase activities, glutathione content, and rates of H2O2 mitochondrial release. Exercise increased oxidative damage in tissues and mitochondria and decreased tissue content of reduced glutathione. Moreover, it increased State 4 and decreased State 3 respiration in tissues and mitochondria. G. sulphuraria supplementation reduced the above exercise-induced variations. Conversely, alga supplementation was not able to modify the exercise-induced increase in mitochondrial release rate of hydrogen peroxide and in liver and heart antioxidant enzyme activities. The alga capacity to reduce lipid oxidative damage without reducing mitochondrial H2O2 release can be due to its high content of C-phycocyanin and glutathione, which are able to scavenge peroxyl radicals and contribute to phospholipid hydroperoxide metabolism, respectively. In conclusion, G. sulphuraria ability to reduce exercise-linked oxidative damage and mitochondrial dysfunction makes it potentially useful even in other conditions leading to oxidative stress, including hyperthyroidism, chronic inflammation, and ischemia/reperfusion. PMID:25874021

Bioheat model evaluations of laser effects on tissues: role of water evaporation and diffusion

NASA Astrophysics Data System (ADS)

Nagulapally, Deepthi; Joshi, Ravi P.; Thomas, Robert J.

2011-03-01

A two-dimensional, time-dependent bioheat model is applied to evaluate changes in temperature and water content in tissues subjected to laser irradiation. Our approach takes account of liquid-to-vapor phase changes and a simple diffusive flow of water within the biotissue. An energy balance equation considers blood perfusion, metabolic heat generation, laser absorption, and water evaporation. The model also accounts for the water dependence of tissue properties (both thermal and optical), and variations in blood perfusion rates based on local tissue injury. Our calculations show that water diffusion would reduce the local temperature increases and hot spots in comparison to simple models that ignore the role of water in the overall thermal and mass transport. Also, the reduced suppression of perfusion rates due to tissue heating and damage with water diffusion affect the necrotic depth. Two-dimensional results for the dynamic temperature, water content, and damage distributions will be presented for skin simulations. It is argued that reduction in temperature gradients due to water diffusion would mitigate local refractive index variations, and hence influence the phenomenon of thermal lensing. Finally, simple quantitative evaluations of pressure increases within the tissue due to laser absorption are presented.

Adaptive vibrational configuration interaction (A-VCI): A posteriori error estimation to efficiently compute anharmonic IR spectra

NASA Astrophysics Data System (ADS)

Garnier, Romain; Odunlami, Marc; Le Bris, Vincent; Bégué, Didier; Baraille, Isabelle; Coulaud, Olivier

2016-05-01

A new variational algorithm called adaptive vibrational configuration interaction (A-VCI) intended for the resolution of the vibrational Schrödinger equation was developed. The main advantage of this approach is to efficiently reduce the dimension of the active space generated into the configuration interaction (CI) process. Here, we assume that the Hamiltonian writes as a sum of products of operators. This adaptive algorithm was developed with the use of three correlated conditions, i.e., a suitable starting space, a criterion for convergence, and a procedure to expand the approximate space. The velocity of the algorithm was increased with the use of a posteriori error estimator (residue) to select the most relevant direction to increase the space. Two examples have been selected for benchmark. In the case of H2CO, we mainly study the performance of A-VCI algorithm: comparison with the variation-perturbation method, choice of the initial space, and residual contributions. For CH3CN, we compare the A-VCI results with a computed reference spectrum using the same potential energy surface and for an active space reduced by about 90%.

Adaptive vibrational configuration interaction (A-VCI): A posteriori error estimation to efficiently compute anharmonic IR spectra.

PubMed

Garnier, Romain; Odunlami, Marc; Le Bris, Vincent; Bégué, Didier; Baraille, Isabelle; Coulaud, Olivier

2016-05-28

A new variational algorithm called adaptive vibrational configuration interaction (A-VCI) intended for the resolution of the vibrational Schrödinger equation was developed. The main advantage of this approach is to efficiently reduce the dimension of the active space generated into the configuration interaction (CI) process. Here, we assume that the Hamiltonian writes as a sum of products of operators. This adaptive algorithm was developed with the use of three correlated conditions, i.e., a suitable starting space, a criterion for convergence, and a procedure to expand the approximate space. The velocity of the algorithm was increased with the use of a posteriori error estimator (residue) to select the most relevant direction to increase the space. Two examples have been selected for benchmark. In the case of H2CO, we mainly study the performance of A-VCI algorithm: comparison with the variation-perturbation method, choice of the initial space, and residual contributions. For CH3CN, we compare the A-VCI results with a computed reference spectrum using the same potential energy surface and for an active space reduced by about 90%.

Evaluating acoustic speaker normalization algorithms: evidence from longitudinal child data.

PubMed

Kohn, Mary Elizabeth; Farrington, Charlie

2012-03-01

Speaker vowel formant normalization, a technique that controls for variation introduced by physical differences between speakers, is necessary in variationist studies to compare speakers of different ages, genders, and physiological makeup in order to understand non-physiological variation patterns within populations. Many algorithms have been established to reduce variation introduced into vocalic data from physiological sources. The lack of real-time studies tracking the effectiveness of these normalization algorithms from childhood through adolescence inhibits exploration of child participation in vowel shifts. This analysis compares normalization techniques applied to data collected from ten African American children across five time points. Linear regressions compare the reduction in variation attributable to age and gender for each speaker for the vowels BEET, BAT, BOT, BUT, and BOAR. A normalization technique is successful if it maintains variation attributable to a reference sociolinguistic variable, while reducing variation attributable to age. Results indicate that normalization techniques which rely on both a measure of central tendency and range of the vowel space perform best at reducing variation attributable to age, although some variation attributable to age persists after normalization for some sections of the vowel space. © 2012 Acoustical Society of America

Mothers' depressive symptoms predict both increased and reduced negative reactivity: aversion sensitivity and the regulation of emotion.

PubMed

Dix, Theodore; Moed, Anat; Anderson, Edward R

2014-07-01

This study examined whether, as mothers' depressive symptoms increase, their expressions of negative emotion to children increasingly reflect aversion sensitivity and motivation to minimize ongoing stress or discomfort. In multiple interactions over 2 years, negative affect expressed by 319 mothers and their children was observed across variations in mothers' depressive symptoms, the aversiveness of children's immediate behavior, and observed differences in children's general negative reactivity. As expected, depressive symptoms predicted reduced maternal negative reactivity when child behavior was low in aversiveness, particularly with children who were high in negative reactivity. Depressive symptoms predicted high negative reactivity and steep increases in negative reactivity as the aversiveness of child behavior increased, particularly when high and continued aversiveness from the child was expected (i.e., children were high in negative reactivity). The findings are consistent with the proposal that deficits in parenting competence as depressive symptoms increase reflect aversion sensitivity and motivation to avoid conflict and suppress children's aversive behavior. © The Author(s) 2014.

Inheritance and World Variation in Thermal Requirements for Egg Hatch in Lymantria dispar (Lepidoptera: Erebidae).

PubMed

Keena, M A

2016-02-01

Mode of inheritance of hatch traits in Lymantria dispar L. was determined by crossing populations nearly fixed for the phenotypic extremes. The nondiapausing phenotype was inherited via a single recessive gene and the phenotype with reduced low temperature exposure requirements before hatch was inherited via a single dominant gene. There was no evidence for sex-linkage or cytoplasmic effects with either gene. Eggs from 43 geographic populations were evaluated for hatch characteristics after being held for 60 d at 5°C followed by incubation at 25°C. There was considerable variation both within and among the populations in the proportion able to hatch, time to first hatch, and average time to hatch. Egg masses with reduced requirement for low temperatures before the eggs were ready to hatch were present in all subspecies of L. dispar and the phenotype was not fixed in most populations. The populations clustered into three distinct groups, and climatic variables were found to be rough predictors of those groups. Variation in hatch phenotypes between populations is likely an adaptation to local climate and within a population provides a bet-hedging strategy to ensure that at least some hatch synchronizes with host leaf-out. Continued vigilance to prevent movement of populations both within and between countries is warranted, because some of the alleles that confer nondiapause or reduced low temperature requirements before egg hatch are not present in all populations and their introduction would increase variation in egg hatch within a population. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by a US Government employee and is in the public domain in the US.

Fighter pilots' heart rate, heart rate variation and performance during instrument approaches.

PubMed

Mansikka, Heikki; Simola, Petteri; Virtanen, Kai; Harris, Don; Oksama, Lauri

2016-10-01

Fighter pilots' heart rate (HR), heart rate variation (HRV) and performance during instrument approaches were examined. The subjects were required to fly instrument approaches in a high-fidelity simulator under various levels of task demand. The task demand was manipulated by increasing the load on the subjects by reducing the range at which they commenced the approach. HR and the time domain components of HRV were used as measures of pilot mental workload (PMWL). The findings of this study indicate that HR and HRV are sensitive to varying task demands. HR and HRV were able to distinguish the level of PMWL after which the subjects were no longer able to cope with the increasing task demands and their instrument landing system performance fell to a sub-standard level. The major finding was the HR/HRV's ability to differentiate the sub-standard performance approaches from the high-performance approaches. Practitioner Summary: This paper examined if HR and HRV were sensitive to varying task demands in a fighter aviation environment and if these measures were related to variations in pilot's performance.

Adverse consequences of neonatal antibiotic exposure.

PubMed

Cotten, Charles M

2016-04-01

Antibiotics have not only saved lives and improved outcomes, but they also influence the evolving microbiome. This review summarizes reports on neonatal infections and variation in antibiotic utilization, discusses the emergence of resistant organisms, and presents data from human neonates and animal models demonstrating the impact of antibiotics on the microbiome, and how microbiome alterations impact health. The importance of antibiotic stewardship is also discussed. Infections increase neonatal morbidity and mortality. Furthermore, the clinical presentation of infections can be subtle, prompting clinicians to empirically start antibiotics when infection is a possibility. Antibiotic-resistant infections are a growing problem. Cohort studies have identified extensive center variations in antibiotic usage and associations between antibiotic exposures and outcomes. Studies of antibiotic-induced microbiome alterations and downstream effects on the developing immune system have increased our understanding of the mechanisms underlying the associations between antibiotics and adverse outcomes. The emergence of resistant microorganisms and recent evidence linking antibiotic practice variations with health outcomes has led to the initiation of antibiotic stewardship programs. The review encourages practitioners to assess local antibiotic use with regard to local microbiology, and to adopt steps to reduce infections and use antibiotics wisely.

Ecological interactions and the fitness effect of water-use efficiency: Competition and drought alter the impact of natural MPK12 alleles in Arabidopsis.

PubMed

Campitelli, Brandon E; Des Marais, David L; Juenger, Thomas E

2016-04-01

The presence of substantial genetic variation for water-use efficiency (WUE) suggests that natural selection plays a role in maintaining alleles that affect WUE. Soil water deficit can reduce plant survival, and is likely to impose selection to increase WUE, whereas competition for resources may select for decreased WUE to ensure water acquisition. We tested the fitness consequences of natural allelic variation in a single gene (MPK12) that influences WUE in Arabidopsis, using transgenic lines contrasting in MPK12 alleles, under four treatments; drought/competition, drought/no competition, well-watered/competition, well-watered/no competition. Results revealed an allele × environment interaction: Low WUE plants performed better in competition, resulting from increased resource consumption. Contrastingly, high WUE individuals performed better in no competition, irrespective of water availability, presumably from enhanced water conservation and nitrogen acquisition. Our findings suggest that selection can influence MPK12 evolution, and represents the first assessment of plant fitness resulting from natural allelic variation at a single locus affecting WUE. © 2016 John Wiley & Sons Ltd/CNRS.

A preliminary estimate of geoid-induced variations in repeat orbit satellite altimeter observations

NASA Technical Reports Server (NTRS)

Brenner, Anita C.; Beckley, B. D.; Koblinsky, C. J.

1990-01-01

Altimeter satellites are often maintained in a repeating orbit to facilitate the separation of sea-height variations from the geoid. However, atmospheric drag and solar radiation pressure cause a satellite orbit to drift. For Geosat this drift causes the ground track to vary by + or - 1 km about the nominal repeat path. This misalignment leads to an error in the estimates of sea surface height variations because of the local slope in the geoid. This error has been estimated globally for the Geosat Exact Repeat Mission using a mean sea surface constructed from Geos 3 and Seasat altimeter data. Over most of the ocean the geoid gradient is small, and the repeat-track misalignment leads to errors of only 1 to 2 cm. However, in the vicinity of trenches, continental shelves, islands, and seamounts, errors can exceed 20 cm. The estimated error is compared with direct estimates from Geosat altimetry, and a strong correlation is found in the vicinity of the Tonga and Aleutian trenches. This correlation increases as the orbit error is reduced because of the increased signal-to-noise ratio.

Interfraction variation in lung tumor position with abdominal compression during stereotactic body radiotherapy

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

Mampuya, Wambaka Ange; Nakamura, Mitsuhiro; Matsuo, Yukinori

2013-09-15

Purpose: To assess the effect of abdominal compression on the interfraction variation in tumor position in lung stereotactic body radiotherapy (SBRT) using cone-beam computed tomography (CBCT) in a larger series of patients with large tumor motion amplitude.Methods: Thirty patients with lung tumor motion exceeding 8 mm who underwent SBRT were included in this study. After translational and rotational initial setup error was corrected based on bone anatomy, CBCT images were acquired for each fraction. The residual interfraction variation was defined as the difference between the centroid position of the visualized target in three dimensions derived from CBCT scans and thosemore » derived from averaged intensity projection images. The authors compared the magnitude of the interfraction variation in tumor position between patients treated with [n= 16 (76 fractions)] and without [n= 14 (76 fractions)] abdominal compression.Results: The mean ± standard deviation (SD) of the motion amplitude in the longitudinal direction before abdominal compression was 19.9 ± 7.3 (range, 10–40) mm and was significantly (p < 0.01) reduced to 12.4 ± 5.8 (range, 5–30) mm with compression. The greatest variance of the interfraction variation with abdominal compression was observed in the longitudinal direction, with a mean ± SD of 0.79 ± 3.05 mm, compared to −0.60 ± 2.10 mm without abdominal compression. The absolute values of the 95th percentile of the interfraction variation for one side in each direction were 3.97/6.21 mm (posterior/anterior), 4.16/3.76 mm (caudal/cranial), and 2.90/2.32 mm (right/left) without abdominal compression, and 2.14/5.03 mm (posterior/anterior), 3.93/9.23 mm (caudal/cranial), and 2.37/5.45 mm (right/left) with abdominal compression. An absolute interfraction variation greater than 5 mm was observed in six (9.2%) fractions without and 13 (17.1%) fractions with abdominal compression.Conclusions: Abdominal compression was effective for reducing the amplitude of tumor motion. However, in most of the authors’ patients, the use of abdominal compression seemed to increase the interfraction variation in tumor position, despite reducing lung tumor motion. The daily tumor position deviated more systematically from the tumor position in the planning CT scan in the lateral and longitudinal directions in patients treated with abdominal compression compared to those treated without compression. Therefore, target matching is required to correct or minimize the interfraction variation.« less

Thermal biology mediates responses of amphibians and reptiles to habitat modification.

PubMed

Nowakowski, A Justin; Watling, James I; Thompson, Michelle E; Brusch, George A; Catenazzi, Alessandro; Whitfield, Steven M; Kurz, David J; Suárez-Mayorga, Ángela; Aponte-Gutiérrez, Andrés; Donnelly, Maureen A; Todd, Brian D

2018-03-01

Human activities often replace native forests with warmer, modified habitats that represent novel thermal environments for biodiversity. Reducing biodiversity loss hinges upon identifying which species are most sensitive to the environmental conditions that result from habitat modification. Drawing on case studies and a meta-analysis, we examined whether observed and modelled thermal traits, including heat tolerances, variation in body temperatures, and evaporative water loss, explained variation in sensitivity of ectotherms to habitat modification. Low heat tolerances of lizards and amphibians and high evaporative water loss of amphibians were associated with increased sensitivity to habitat modification, often explaining more variation than non-thermal traits. Heat tolerances alone explained 24-66% (mean = 38%) of the variation in species responses, and these trends were largely consistent across geographic locations and spatial scales. As habitat modification alters local microclimates, the thermal biology of species will likely play a key role in the reassembly of terrestrial communities. © 2018 John Wiley & Sons Ltd/CNRS.

Oral Morphine Use in South India: A Population-Based Study

PubMed Central

Karim, Safiya; Booth, Christopher M.

2017-01-01

Purpose Access to opioids for pain control is recognized as an urgent issue in low- and middle-income countries. Here we report temporal and regional trends in morphine use in Kerala, India. Methods Oral morphine use data for the State of Kerala (2012 to 2015) was used to describe temporal trends, regional variation, and provider characteristics. Total morphine use was calculated for each district of Kerala to derive an annual per capita use rate (milligrams per capita). Each provider was classified as government, private, nongovernment organization (NGO), or NGO partnership. Results Oral morphine use for Kerala was 1.32 mg/capita and increased over the study period 27% (from 1.23 mg/capita to 1.56 mg/capita). There was substantial variation in morphine use across districts (range, 0.49 mg/capita to 2.97 mg/capita; six-fold difference). This variation increased over time (19-fold difference in 2015). In 2015, 31% of morphine providers (51 of 167) were government institutions; they delivered 48% of total morphine in Kerala. Corresponding data for other providers are private institutions, 23% of centers and 13% of morphine; NGOs, 41% of centers and 34% of morphine; and NGO partnerships, 5% of centers and 4% of morphine. From 2012 to 2015, the total number of centers increased by 35%, from 124 to 167. Conclusion Oral morphine use has increased over time in Kerala but remains substantially lower than estimated need. There is significant geographic variation of use. Efforts are needed to improve palliative care in Kerala and to reduce regional disparities in access to opioids. PMID:29244992

Effects of external stream flow and afterbody variations on the performance of a plug nozzle

NASA Technical Reports Server (NTRS)

Salmi, R J; Cortright, E M , Jr

1956-01-01

The off-design operation of an isentropic plug nozzle designed for a jet pressure ratio of 15 was investigated experimentally at subsonic Mach numbers up to 0.9 and jet pressure ratios up to 5. When installed in a cylindrical nacelle with a sharp turn at the nozzle lip, the interaction of the jet and the external stream produced low pressures on the base formed by the high lip angle. These low pressures increased the nacelle drag and caused an overexpansion of the jet, which resulted in lower pressures on the plug and, hence, reduced thrust. With a boattail ahead of the plug nozzle, the base pressures were increased and the jet overexpansion significantly reduced.

Age variation in the body coloration of the orb-weaver spider Alpaida tuonabo and its implications on foraging.

PubMed

Gálvez, Dumas; Añino, Yostin; De la O, Jorge M

2018-02-26

Spiders show a repertoire of strategies to increase their foraging success. In particular, some orb-weaver spiders use attractive body colorations to lure prey. Interestingly, coloration varies with age in many species, which may result in ontogenetic variation of foraging success. By using field observations, laboratory experiments and spectrophotometric analysis, we investigated whether pale juveniles and bright adults of the orb-weaver Alpaida tuonabo use different foraging strategies due to ontogenetic variation in coloration. Field observations revealed that foraging success of juveniles and adults was influenced by web properties. However, foraging success increased with body size only in adults, supporting the idea that larger individuals produce a stronger visual signal for prey. The attractiveness of the adult coloration for prey was confirmed in the laboratory with frame-web-choice experiments, in which webs bearing a spider intercepted more bees than empty webs. Our spectrophotometric analysis suggests that the yellow coloration may produce the deceiving signal for prey. Moreover, we identified potential alternative foraging strategies: cryptic juveniles at higher heights and 'attractive' adults at lower heights. This study reveals how ontogenetic colour variation may favour the use of alternative foraging strategies in orb-weaver spiders and reduces intraspecific competition.

Global Precipitation Variations and Long-term Changes Derived from the GPCP Monthly Product

NASA Technical Reports Server (NTRS)

Adler, Robert F.; Gu, Guojun; Huffman, George; Curtis, Scott

2005-01-01

Global and large regional rainfall variations and possible long-term changes are examined using the 25-year (1979-2004) monthly dataset from the Global Precipitation Climatology Project (GPCP). The emphasis is to discriminate among the variations due to ENSO, volcanic events and possible long-term changes. Although the global change of precipitation in the data set is near zero, the data set does indicate an upward trend (0.13 mm/day/25yr) and a downward trend (-0.06 mm/day/25yr) over tropical oceans and lands (25S-25N), respectively. This corresponds to a 4% increase (ocean) and 2% decrease (land) during this time period. Techniques are applied to attempt to eliminate variations due to ENSO and major volcanic eruptions. The impact of the two major volcanic eruptions over the past 25 years is estimated to be about a 5% reduction in tropical rainfall. The modified data set (with ENSO and volcano effect removed) retains the same approximate change slopes, but with reduced variance leading to significance tests with results in the 90-95% range. Inter-comparisons between the GPCP, SSWI (1988-2004), and TRMM (1998-2004) rainfall products are made to increase or decrease confidence in the changes seen in the GPCP analysis.

Length Variation, Heteroplasmy and Sequence Divergence in the Mitochondrial DNA of Four Species of Sturgeon (Acipenser)

PubMed Central

Brown, J. R.; Beckenbach, K.; Beckenbach, A. T.; Smith, M. J.

1996-01-01

The extent of mtDNA length variation and heteroplasmy as well as DNA sequences of the control region and two tRNA genes were determined for four North American sturgeon species: Acipenser transmontanus, A. medirostris, A. fulvescens and A. oxyrhnychus. Across the Continental Divide, a division in the occurrence of length variation and heteroplasmy was observed that was concordant with species biogeography as well as with phylogenies inferred from restriction fragment length polymorphisms (RFLP) of whole mtDNA and pairwise comparisons of unique sequences of the control region. In all species, mtDNA length variation was due to repeated arrays of 78-82-bp sequences each containing a D-loop strand synthesis termination associated sequence (TAS). Individual repeats showed greater sequence conservation within individuals and species rather than between species, which is suggestive of concerted evolution. Differences in the frequencies of multiple copy genomes and heteroplasmy among the four species may be ascribed to differences in the rates of recurrent mutation. A mechanism that may offset the high rate of mutation for increased copy number is suggested on the basis that an increase in the number of functional TAS motifs might reduce the frequency of successfully initiated H-strand replications. PMID:8852850

Damping Experiment of Spinning Composite Plates With Embedded Viscoelastic Material

NASA Technical Reports Server (NTRS)

Mehmed, Oral

1998-01-01

One way to increase gas turbine engine blade reliability and durability is to reduce blade vibration. It is well known that vibration can be reduced by adding damping to metal and composite blade-disk systems. As part of a joint research effort of the NASA Lewis Research Center and the University of California, San Diego, the use of integral viscoelastic damping treatment to reduce the vibration of rotating composite fan blades was investigated. The objectives of this experiment were to verify the structural integrity of composite plates with viscoelastic material patches embedded between composite layers while under large steady forces from spinning, and to measure the damping and natural frequency variation with rotational speed.

Variation in work tasks in relation to pinch grip strength among middle-aged female dentists.

PubMed

Ding, Hebo; Leino-Arjas, Päivi; Murtomaa, Heikki; Takala, Esa-Pekka; Solovieva, Svetlana

2013-11-01

We aimed to investigate the relationship of task variation during dental work history with pinch grip strength among dentists. We measured pinch grip strength among 295 female Finnish dentists aged 45-63 years. Variation in dental work tasks during work history was empirically defined by cluster analysis. Three clusters of task variation emerged: low (most work time in restoration treatment/endodontics), moderate (about 50% in the former and 50% in prosthodontics/periodontics/surgery), and high (variable tasks including administrative duties). Hand radiographs were examined for the presence of OA in the wrist and each joint of the 1-3rd fingers. Information on hand-loading leisure-time activities, and joint pain was obtained by questionnaire. Glove size was used as a proxy for hand size. BMI (kg/m2) was based on measured weight and self-reported height. Dentists with low variation of work task history had an increased risk of low pinch grip strength in the right hand (OR 2.3, 95% CI 1.2-4.3), but not in the left (1.13, 0.62-2.08), compared to dentists with high task variation, independent of age, hand size, hand-loading leisure-time activities, BMI and symptomatic hand OA. The dentists with the most hand-loading tasks were at an increased risk of low pinch grip strength, independent of e.g. symptomatic hand OA. It is advisable among dentists to perform as diverse work tasks as possible to reduce the risk of decreased pinch grip strength. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Variation in tibial functionality and fracture susceptibility among healthy, young adults arises from the acquisition of biologically distinct sets of traits.

PubMed

Jepsen, Karl J; Evans, Rachel; Negus, Charles H; Gagnier, Joel J; Centi, Amanda; Erlich, Tomer; Hadid, Amir; Yanovich, Ran; Moran, Daniel S

2013-06-01

Physiological systems like bone respond to many genetic and environmental factors by adjusting traits in a highly coordinated, compensatory manner to establish organ-level function. To be mechanically functional, a bone should be sufficiently stiff and strong to support physiological loads. Factors impairing this process are expected to compromise strength and increase fracture risk. We tested the hypotheses that individuals with reduced stiffness relative to body size will show an increased risk of fracturing and that reduced strength arises from the acquisition of biologically distinct sets of traits (ie, different combinations of morphological and tissue-level mechanical properties). We assessed tibial functionality retrospectively for 336 young adult women and men engaged in military training, and calculated robustness (total area/bone length), cortical area (Ct.Ar), and tissue-mineral density (TMD). These three traits explained 69% to 72% of the variation in tibial stiffness (p < 0.0001). Having reduced stiffness relative to body size (body weight × bone length) was associated with odds ratios of 1.5 (95% confidence interval [CI], 0.5-4.3) and 7.0 (95% CI, 2.0-25.1) for women and men, respectively, for developing a stress fracture based on radiography and scintigraphy. K-means cluster analysis was used to segregate men and women into subgroups based on robustness, Ct.Ar, and TMD adjusted for body size. Stiffness varied 37% to 42% among the clusters (p < 0.0001, ANOVA). For men, 78% of stress fracture cases segregated to three clusters (p < 0.03, chi-square). Clusters showing reduced function exhibited either slender tibias with the expected Ct.Ar and TMD relative to body size and robustness (ie, well-adapted bones) or robust tibias with reduced residuals for Ct.Ar or TMD relative to body size and robustness (ie, poorly adapted bones). Thus, we show there are multiple biomechanical and thus biological pathways leading to reduced function and increased fracture risk. Our results have important implications for developing personalized preventative diagnostics and treatments. Copyright © 2013 American Society for Bone and Mineral Research.

Exponentially Decelerated Contrast Media Injection Rate Combined With a Novel Patient-Specific Contrast Formula Reduces Contrast Volume Administration and Radiation Dose During Computed Tomography Pulmonary Angiography.

PubMed

Saade, Charbel; Mayat, Ahmad; El-Merhi, Fadi

2016-01-01

Matching contrast injection timing with vessel dynamics significantly improves vessel opacification and reduces contrast dose in the assessment of pulmonary embolism during computed tomography (CT) pulmonary angiography. The aim of this study was to investigate opacification of the pulmonary vasculature (PV) during CT pulmonary angiography using a patient-specific contrast formula (PSCF) and exponentially decelerated contrast media (EDCM) injection rate. Institutional review board approved this retrospective study. Computed tomography pulmonary angiography was performed on 200 patients with suspected pulmonary embolism using a 64-channel CT scanner. Patient demographics were equally distributed. Patients were randomly assigned to 2 equal protocol groups: protocol A used a PSCF, and protocol B involved the use of a PSCF combined with EDCM. The mean cross-sectional opacification profile of 8 central and 11 peripheral PVs were measured for each patient, and arteriovenous contrast ratio was calculated. Protocols were compared using Mann-Whitney U nonparametric statistics. Jackknife alternative free-response receiver operating characteristic analyses were used to assess diagnostic efficacy. Interobserver variations were investigated using kappa methods. A number of pulmonary arteries demonstrated increases in opacification (P < 0.02) for protocol B compared with A, whereas opacification in all veins was reduced in protocol B (P < 0.03). Subsequently, increased arteriovenous contrast ratio in protocol B compared with A was observed at all anatomic locations (P < 0.0002). An increase in jackknife alternative free-response receiver operating characteristic figure of merit (P < 0.0002) and interobserver variation was observed with protocol B compared with protocol A (κ = 0.3-0.73). Mean contrast volume was reduced in protocol B (29 [4] mL) compared with protocol A (33 [9] mL). Mean effective radiation dose in protocol B (1.2 [0.4] mSv) was reduced by 14% compared with protocol A (1.4 [0.6] mSv). Significant improvements in visualization of the PV can be achieved with a low contrast volume using an EDCM and PSCF. The reduced risk of cancer induction is highlighted.

Variation in chlorophyll content per unit leaf area in spring wheat and implications for selection in segregating material.

PubMed

Hamblin, John; Stefanova, Katia; Angessa, Tefera Tolera

2014-01-01

Reduced levels of leaf chlorophyll content per unit leaf area in crops may be of advantage in the search for higher yields. Possible reasons include better light distribution in the crop canopy and less photochemical damage to leaves absorbing more light energy than required for maximum photosynthesis. Reduced chlorophyll may also reduce the heat load at the top of canopy, reducing water requirements to cool leaves. Chloroplasts are nutrient rich and reducing their number may increase available nutrients for growth and development. To determine whether this hypothesis has any validity in spring wheat requires an understanding of genotypic differences in leaf chlorophyll content per unit area in diverse germplasm. This was measured with a SPAD 502 as SPAD units. The study was conducted in series of environments involving up to 28 genotypes, mainly spring wheat. In general, substantial and repeatable genotypic variation was observed. Consistent SPAD readings were recorded for different sampling positions on leaves, between different leaves on single plant, between different plants of the same genotype, and between different genotypes grown in the same or different environments. Plant nutrition affected SPAD units in nutrient poor environments. Wheat genotypes DBW 10 and Transfer were identified as having consistent and contrasting high and low average SPAD readings of 52 and 32 units, respectively, and a methodology to allow selection in segregating populations has been developed.

Human genetic variation in VAC14 regulates Salmonella invasion and typhoid fever through modulation of cholesterol.

PubMed

Alvarez, Monica I; Glover, Luke C; Luo, Peter; Wang, Liuyang; Theusch, Elizabeth; Oehlers, Stefan H; Walton, Eric M; Tram, Trinh Thi Bich; Kuang, Yu-Lin; Rotter, Jerome I; McClean, Colleen M; Chinh, Nguyen Tran; Medina, Marisa W; Tobin, David M; Dunstan, Sarah J; Ko, Dennis C

2017-09-12

Risk, severity, and outcome of infection depend on the interplay of pathogen virulence and host susceptibility. Systematic identification of genetic susceptibility to infection is being undertaken through genome-wide association studies, but how to expeditiously move from genetic differences to functional mechanisms is unclear. Here, we use genetic association of molecular, cellular, and human disease traits and experimental validation to demonstrate that genetic variation affects expression of VAC14, a phosphoinositide-regulating protein, to influence susceptibility to Salmonella enterica serovar Typhi ( S Typhi) infection. Decreased VAC14 expression increased plasma membrane cholesterol, facilitating Salmonella docking and invasion. This increased susceptibility at the cellular level manifests as increased susceptibility to typhoid fever in a Vietnamese population. Furthermore, treating zebrafish with a cholesterol-lowering agent, ezetimibe, reduced susceptibility to S Typhi. Thus, coupling multiple genetic association studies with mechanistic dissection revealed how VAC14 regulates Salmonella invasion and typhoid fever susceptibility and may open doors to new prophylactic/therapeutic approaches.

Trends and Variations of Ocean Surface Latent Heat Flux: Results from GSSTF2c Data Set

NASA Technical Reports Server (NTRS)

Gao, Si; Chiu, Long S.; Shie, Chung-Lin

2013-01-01

Trends and variations of Goddard Satellite-based Surface Turbulent Fluxes (GSSTF) version 2c (GSSTF2c) latent heat flux (LHF) are examined. This version of LHF takes account of the correction in Earth incidence angle. The trend of global mean LHF for GSSTF2c is much reduced relative to GSSTF version 2b Set 1 and Set 2 for the same period 1988-2008. Temporal increase of GSSTF2c LHF in the two decades is 11.0%, in which 3.1%, 5.8%, and 2.1% are attributed to the increase in wind, the increase in sea surface saturated air humidity, and the decrease in near-surface air humidity, respectively. The first empirical orthogonal function of LHF is a conventional El Nino Southern Oscillation (ENSO) mode. However, the trends in LHF are independent of conventional ENSO phenomena. After removing ENSO signal, the pattern of LHF trends is primarily determined by the pattern of air-sea humidity difference trends.

Human genetic variation in VAC14 regulates Salmonella invasion and typhoid fever through modulation of cholesterol

PubMed Central

Alvarez, Monica I.; Glover, Luke C.; Luo, Peter; Wang, Liuyang; Theusch, Elizabeth; Oehlers, Stefan H.; Walton, Eric M.; Tram, Trinh Thi Bich; Kuang, Yu-Lin; Rotter, Jerome I.; McClean, Colleen M.; Chinh, Nguyen Tran; Medina, Marisa W.; Dunstan, Sarah J.

2017-01-01

Risk, severity, and outcome of infection depend on the interplay of pathogen virulence and host susceptibility. Systematic identification of genetic susceptibility to infection is being undertaken through genome-wide association studies, but how to expeditiously move from genetic differences to functional mechanisms is unclear. Here, we use genetic association of molecular, cellular, and human disease traits and experimental validation to demonstrate that genetic variation affects expression of VAC14, a phosphoinositide-regulating protein, to influence susceptibility to Salmonella enterica serovar Typhi (S. Typhi) infection. Decreased VAC14 expression increased plasma membrane cholesterol, facilitating Salmonella docking and invasion. This increased susceptibility at the cellular level manifests as increased susceptibility to typhoid fever in a Vietnamese population. Furthermore, treating zebrafish with a cholesterol-lowering agent, ezetimibe, reduced susceptibility to S. Typhi. Thus, coupling multiple genetic association studies with mechanistic dissection revealed how VAC14 regulates Salmonella invasion and typhoid fever susceptibility and may open doors to new prophylactic/therapeutic approaches. PMID:28827342

Effects of pacing magnitudes and forms on bistability width in a modeled ventricular tissue

NASA Astrophysics Data System (ADS)

Huang, Xiaodong; Liu, Xuemei; Zheng, Lixian; Mi, Yuanyuan; Qian, Yu

2013-07-01

Bistability in periodically paced cardiac tissue is relevant to cardiac arrhythmias and its control. In the present paper, one-dimensional tissue of the phase I Luo-Rudy model is numerically investigated. The effects of various parameters of pacing signals on bistability width are studied. The following conclusions are obtained: (i) Pacing can be classified into two types: pulsatile and sinusoidal types. Pulsatile pacing reduces bistability width as its magnitude is increased. Sinusoidal pacing increases the width as its amplitude is increased. (ii) In a pacing period the hyperpolarizing part plays a more important role than the depolarizing part. Variations of the hyperpolarizing ratio in a period evidently change the width of bistability and its variation tendency. (iii) A dynamical mechanism is proposed to qualitatively explain the phenomena, which reveals the reason for the different effects of pulsatile and sinusoidal pacing on bistability. The methods for changing bistability width by external pacing may help control arrhythmias in cardiology.

A mechanism for inducing climatic variations through ozone destruction: Screening of galactic cosmic rays by solar and terrestrial magnetic fields

NASA Technical Reports Server (NTRS)

Chamberlain, J. W.

1976-01-01

A perturbation analysis, allowing for temperature and opacity feedbacks, is developed to calculate depletions in the O3 abundance and reductions of stratospheric solar heating that result from increases in NOx concentration. A pair of perturbation coefficients give the reduction in O3 and temperature through the stratosphere for a specified NOx increase. This type of analysis illustrates the tendency for various levels to self-heal when a perturbation occurs. Physical arguments indicate that the expected sign of the climatic effect is correct, with colder surface temperatures produced by reduced magnetic shielding. In addition, four qualitative reasons are suggested for thinking that significant ozone reductions by cosmic ray influxes will lead to an increased terrestrial albedo from stratospheric condensation. In this view, long-term (approximately 10,000 years) climatic changes have resulted from secular geomagnetic variations while shorter (approximately 100 years) excursions are related to changes in solar activity.

Passive microwave sensing of soil moisture content - The effects of soil bulk density and surface roughness

NASA Technical Reports Server (NTRS)

Wang, J. R.

1983-01-01

Microwave radiometric measurements over bare fields of different surface roughness were made at frequencies of 1.4 GHz, 5 GHz, and 10.7 GHz to study the frequency dependence, as well as the possible time variation, of surface roughness. An increase in surface roughness was found to increase the brightness temperature of soils and reduce the slope of regression between brightness temperature and soil moisture content. The frequency dependence of the surface roughness effect was relatively weak when compared with that of the vegetation effect. Radiometric time-series observations over a given field indicate that field surface roughness might gradually diminish with time, especially after a rainfall or irrigation. The variation of surface roughness increases the uncertainty of remote soil moisture estimates by microwave radiometry. Three years of radiometric measurements over a test site revealed a possible inconsistency in the soil bulk density determination, which is an important factor in the interpretation of radiometric data.

Variation of renal function over time is associated with major bleeding in patients treated with direct oral anticoagulants for atrial fibrillation.

PubMed

Becattini, C; Giustozzi, M; Ranalli, M G; Bogliari, G; Cianella, F; Verso, M; Agnelli, G; Vedovati, M C

2018-05-01

Essential In patients on treatment with direct anticoagulants (DOACs) variation of renal function is common. The effect of variations of renal function over time on major bleeding is not well defined. Variation of renal function over time is an independent predictor of major bleeding. Identifying conditions associated with variation of renal function may increase safety of DOACs. Background Chronic kidney disease is a risk factor for major bleeding in patients with atrial fibrillation (AF) treated with warfarin. Objective To assess the effect of variations in renal function over time on the risk of major bleeding during treatment with direct oral anticoagulants (DOACs) in patients with non-valvular AF. Methods Consecutive AF patients were prospectively followed after they had received the first DOAC prescription. Estimated glomerular filtration rate (eGFR) was periodically assessed, and the incidence of major bleeding was recorded. A joint survival model was used to estimate the association between variation in eGFR and the risk of major bleeding. Results During a mean follow-up of 575 days, 44 major bleeds occurred in 449 patients (6.1% per patient-year). eGFR over time was inversely and independently associated with the risk of major bleeding; every 1 mL min -1 absolute decrease in eGFR was associated with a 2% increase in the risk of major bleeding (hazard ratio [HR] 1.02, 95% confidence interval [CI] 1.01-1.04). A similar effect of the variation in eGFR over time was observed on the risk of clinically relevant non-major bleeding (HR 1.02, 95% CI 1.01-1.03). Deterioration of renal function leading to a change in eGFR staging was associated with an increase in the risk of major bleeding (HR 2.43, 95% CI 1.33-4.45). Conclusions Variation in renal function over time is associated with the risk of major bleeding in AF patients treated with DOACs in real life. Identification of intervening clinical conditions associated with variation in renal function is essential to reduce the risk of major bleeding and to make DOAC treatment more safe. © 2018 International Society on Thrombosis and Haemostasis.

[What do functionally defined populations contribute to the explanation of regional differences in medical care?].

PubMed

Graf von Stillfried, D; Czihal, T

2014-02-01

Geographic variation in health care is increasingly subject to analysis and health policy aiming at the suitable allocation of resources and the reduction of unwarranted variation for the patient populations concerned. As in the case of area-level indicators, in most cases populations are geographically defined. The concept of geographically defined populations, however, may be self-limiting with respect to identifying the potential for improvement. As an alternative, we explored how a functional definition of populations would support defining the scope for reducing unwarranted geographical variations. Given that patients in Germany have virtually no limits in accessing physicians of their choice, we adapted a method that has been developed in the United States to create virtual networks of physicians based on commonly treated patients. Using the physician claims data under statutory insurance, which covers 90% of the population, we defined 43,006 populations-and networks-in 2010. We found that there is considerable variation between the population in terms of their risk structure and the share of the primary care practice in the total services provided. Moreover, there are marked differences in the size and structure of networks between cities, densely populated regions, and rural regions. We analyzed the variation for two area-level indicators: the proportion of diabetics with at least one HbA1c test per year for diabetics, and the proportion of patients with low back pain undergoing computed tomography and/or magnetic resonance imaging. Variation at the level of functionally defined populations proved to be larger than for geographically defined populations. The pattern of distribution gives evidence on the degree to which consensus targets could be reached and which networks need to be addressed in order to reduce unwarranted regional variation. The concept of functionally defined populations needs to be further developed before implementation.

Does increasing daylength control seasonal changes in clutch sizes of Northern Pintails (Anas acuta)?

USGS Publications Warehouse

Krapu, G.L.; Sargeant, G.A.; Perkins, A.E.H.

2002-01-01

We evaluated spatiotemporal variation in clutch sizes of Northern Pintails (pintails; Anas acuta) nesting in California (1985 to 1996), North Dakota (1982 to 1985), Saskatchewan (1982 to 1985) and Alaska (1991 to 1993) to determine whether seasonal declines in clutch size varied in ways that were consistent with a controlling influence of increasing day length. Pintails began nesting in mid-March in California, mid-April in North Dakota and Saskatchewan, and mid-May in Alaska. Observed durations of nesting were 70 ± 2.6 days (SE) in California, 60 ± 6.3 days in North Dakota, 66 ± 1.3 days in Saskatchewan, and 42 ± 0.7 days in Alaska. Annual differences were the principal source of variation in mean clutch sizes (σ̂Y2 = 0.15, SE = 0.049), which varied little among study locations (σ̂A2 = 0.002, SE = 0.013). Predicted rates of seasonal decline in clutch sizes increased with latitude early in the nesting season, but declined as the nesting season progressed, except in California. Rates of decline in clutch sizes thus were not directly related to rates of increase in day length. Predicted declines in numbers of eggs per clutch over the nesting season were similar for all four locations (range, 3.05–3.12) despite wide variation in durations of nesting. Evidence suggests that reduced nutrient availability during nesting contributes to a higher rate of decline in clutch sizes in Alaska than in temperate regions. Pintails that nest early lay large initial clutches, but thereafter clutch sizes decline rapidly and breeding terminates early. This reproductive strategy is adaptive because young that hatch earliest exhibit the highest survival rates; however, the conversion of grassland to cropland on the primary prairie breeding grounds has reduced hatching rates of clutches laid early in the nesting season. Under these conditions, the limited capacity to renest in late spring on their prairie breeding grounds probably has contributed to Pintail population declines.

Contrasting suspended covers reveal the impact of an artificial monolayer on heat transfer processes at the interfacial boundary layer.

PubMed

Pittaway, P; Martínez-Alvarez, V; Hancock, N

2015-01-01

The highly variable performance of artificial monolayers in reducing evaporation from water storages has been attributed to wind speed and wave turbulence. Other factors operating at the interfacial boundary layer have seldom been considered. In this paper, two physical shade covers differing in porosity and reflectivity were suspended over 10 m diameter water tanks to attenuate wind and wave turbulence. The monolayer octadecanol was applied to one of the covered tanks, and micrometeorological conditions above and below the covers were monitored to characterise diurnal variation in the energy balance. A high downward (air-to-water) convective heat flux developed under the black cover during the day, whereas diurnal variation in the heat flux under the more reflective, wind-permeable white cover was much less. Hourly air and water temperature profiles under the covers over 3 days when forced convection was minimal (low wind speed) were selected for analysis. Monolayer application reduced temperature gain in surface water under a downward convective heat flux, and conversely reduced temperature loss under an upward convective heat flux. This 'dual property' may explain why repeat application of an artificial monolayer to retard evaporative loss (reducing latent heat loss) does not inevitably increase water temperature.

Stabilization of memory States by stochastic facilitating synapses.

PubMed

Miller, Paul

2013-12-06

Bistability within a small neural circuit can arise through an appropriate strength of excitatory recurrent feedback. The stability of a state of neural activity, measured by the mean dwelling time before a noise-induced transition to another state, depends on the neural firing-rate curves, the net strength of excitatory feedback, the statistics of spike times, and increases exponentially with the number of equivalent neurons in the circuit. Here, we show that such stability is greatly enhanced by synaptic facilitation and reduced by synaptic depression. We take into account the alteration in times of synaptic vesicle release, by calculating distributions of inter-release intervals of a synapse, which differ from the distribution of its incoming interspike intervals when the synapse is dynamic. In particular, release intervals produced by a Poisson spike train have a coefficient of variation greater than one when synapses are probabilistic and facilitating, whereas the coefficient of variation is less than one when synapses are depressing. However, in spite of the increased variability in postsynaptic input produced by facilitating synapses, their dominant effect is reduced synaptic efficacy at low input rates compared to high rates, which increases the curvature of neural input-output functions, leading to wider regions of bistability in parameter space and enhanced lifetimes of memory states. Our results are based on analytic methods with approximate formulae and bolstered by simulations of both Poisson processes and of circuits of noisy spiking model neurons.

Variations in dissolved organic nitrogen concentration in biofilters with different media during drinking water treatment.

PubMed

Zhang, Huining; Zhang, Kefeng; Jin, Huixia; Gu, Li; Yu, Xin

2015-11-01

Dissolved organic nitrogen (DON) is potential precursor of disinfection byproducts (DBPs), especially nitrogenous DBPs. In this study, we investigated the impact of biofilters on DON concentration changes in a drinking water plant. A small pilot plant was constructed next to a sedimentation tank in a drinking water plant and included activated carbon, quartz sand, anthracite, and ceramsite biofilters. As the biofilter layer depth increased, the DON concentration first decreased and then increased, and the variation in DON concentration differed among the biofilters. In the activated carbon biofilter, the DON concentration was reduced by the largest amount in the first part of the column and increased by the largest amount in the second part of the column. The biomass in the activated carbon filter was less than that in the quartz sand filter in the upper column. The heterotrophic bacterial proportion among bacterial flora in the activated carbon biofilter was the largest, which might be due to the significant reduction in DON in the first part of the column. Overall, the results indicate that the DON concentration in biofiltered water can be controlled via the selection of appropriate biofilter media. We propose that a two-layer biofilter with activated carbon in the upper layer and another media type in the lower layer could best reduce the DON concentration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Response of Water Use Efficiency to Global Environmental Change Based on Output From Terrestrial Biosphere Models

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

Zhou, Sha; Yu, Bofu; Schwalm, Christopher R.

Here, water use efficiency (WUE), defined as the ratio of gross primary productivity and evapotranspiration at the ecosystem scale, is a critical variable linking the carbon and water cycles. Incorporating a dependency on vapor pressure deficit, apparent underlying WUE (uWUE) provides a better indicator of how terrestrial ecosystems respond to environmental changes than other WUE formulations. Here we used 20th century simulations from four terrestrial biosphere models to develop a novel variance decomposition method. With this method, we attributed variations in apparent uWUE to both the trend and interannual variation of environmental drivers. The secular increase in atmospheric CO 2more » explained a clear majority of total variation (66 ± 32%: mean ± one standard deviation), followed by positive trends in nitrogen deposition and climate, as well as a negative trend in land use change. In contrast, interannual variation was mostly driven by interannual climate variability. To analyze the mechanism of the CO 2 effect, we partitioned the apparent uWUE into the transpiration ratio (transpiration over evapotranspiration) and potential uWUE. The relative increase in potential uWUE parallels that of CO 2, but this direct CO 2 effect was offset by 20 ± 4% by changes in ecosystem structure, that is, leaf area index for different vegetation types. However, the decrease in transpiration due to stomatal closure with rising CO 2 was reduced by 84% by an increase in leaf area index, resulting in small changes in the transpiration ratio. CO 2 concentration thus plays a dominant role in driving apparent uWUE variations over time, but its role differs for the two constituent components: potential uWUE and transpiration.« less

Evaluation of the temporal variations of air quality in Taipei City, Taiwan, from 1994 to 2003.

PubMed

Chang, Shuenn-Chin; Lee, Chung-Te

2008-03-01

Data collected from the five air-quality monitoring stations established by the Taiwan Environmental Protection Administration in Taipei City from 1994 to 2003 are analyzed to assess the temporal variations of air quality. Principal component analysis (PCA) is adopted to convert the original measuring pollutants into fewer independent components through linear combinations while still retaining the majority of the variance of the original data set. Two principal components (PCs) are retained together explaining 82.73% of the total variance. PC1, which represents primary pollutants such as CO, NO(x), and SO(2), shows an obvious decrease over the last 10 years. PC2, which represents secondary pollutants such as ozone, displays a yearly increase over the time period when a reduction of primary pollutants is obvious. In order to track down the control measures put forth by the authorities, 47 days of high PM(10) concentrations caused by transboundary transport have been eliminated in analyzing the long-term trend of PM(10) in Taipei City. The temporal variations over the past 10 years show that the moderate peak in O(3) demonstrates a significant upward trend even when the local primary pollutants have been well under control. Monthly variations of PC scores demonstrate that primary pollution is significant from January to April, while ozone increases from April to August. The results of the yearly variations of PC scores show that PM(10) has gradually shifted from a strong correlation with PC1 during the early years to become more related to PC2 in recent years. This implies that after a reduction of primary pollutants, the proportion of secondary aerosols in PM(10) may increase. Thus, reducing the precursor concentrations of secondary aerosols will be an effective way to lower PM(10) concentrations.

Elucidating the impact of temperature variability and extremes on cereal croplands through remote sensing.

PubMed

Duncan, John M A; Dash, Jadunandan; Atkinson, Peter M

2015-04-01

Remote sensing-derived wheat crop yield-climate models were developed to highlight the impact of temperature variation during thermo-sensitive periods (anthesis and grain-filling; TSP) of wheat crop development. Specific questions addressed are: can the impact of temperature variation occurring during the TSP on wheat crop yield be detected using remote sensing data and what is the impact? Do crop critical temperature thresholds during TSP exist in real world cropping landscapes? These questions are tested in one of the world's major wheat breadbaskets of Punjab and Haryana, north-west India. Warming average minimum temperatures during the TSP had a greater negative impact on wheat crop yield than warming maximum temperatures. Warming minimum and maximum temperatures during the TSP explain a greater amount of variation in wheat crop yield than average growing season temperature. In complex real world cereal croplands there was a variable yield response to critical temperature threshold exceedance, specifically a more pronounced negative impact on wheat yield with increased warming events above 35 °C. The negative impact of warming increases with a later start-of-season suggesting earlier sowing can reduce wheat crop exposure harmful temperatures. However, even earlier sown wheat experienced temperature-induced yield losses, which, when viewed in the context of projected warming up to 2100 indicates adaptive responses should focus on increasing wheat tolerance to heat. This study shows it is possible to capture the impacts of temperature variation during the TSP on wheat crop yield in real world cropping landscapes using remote sensing data; this has important implications for monitoring the impact of climate change, variation and heat extremes on wheat croplands. © 2014 John Wiley & Sons Ltd.

Response of Water Use Efficiency to Global Environmental Change Based on Output From Terrestrial Biosphere Models

NASA Astrophysics Data System (ADS)

Zhou, Sha; Yu, Bofu; Schwalm, Christopher R.; Ciais, Philippe; Zhang, Yao; Fisher, Joshua B.; Michalak, Anna M.; Wang, Weile; Poulter, Benjamin; Huntzinger, Deborah N.; Niu, Shuli; Mao, Jiafu; Jain, Atul; Ricciuto, Daniel M.; Shi, Xiaoying; Ito, Akihiko; Wei, Yaxing; Huang, Yuefei; Wang, Guangqian

2017-11-01

Water use efficiency (WUE), defined as the ratio of gross primary productivity and evapotranspiration at the ecosystem scale, is a critical variable linking the carbon and water cycles. Incorporating a dependency on vapor pressure deficit, apparent underlying WUE (uWUE) provides a better indicator of how terrestrial ecosystems respond to environmental changes than other WUE formulations. Here we used 20th century simulations from four terrestrial biosphere models to develop a novel variance decomposition method. With this method, we attributed variations in apparent uWUE to both the trend and interannual variation of environmental drivers. The secular increase in atmospheric CO2 explained a clear majority of total variation (66 ± 32%: mean ± one standard deviation), followed by positive trends in nitrogen deposition and climate, as well as a negative trend in land use change. In contrast, interannual variation was mostly driven by interannual climate variability. To analyze the mechanism of the CO2 effect, we partitioned the apparent uWUE into the transpiration ratio (transpiration over evapotranspiration) and potential uWUE. The relative increase in potential uWUE parallels that of CO2, but this direct CO2 effect was offset by 20 ± 4% by changes in ecosystem structure, that is, leaf area index for different vegetation types. However, the decrease in transpiration due to stomatal closure with rising CO2 was reduced by 84% by an increase in leaf area index, resulting in small changes in the transpiration ratio. CO2 concentration thus plays a dominant role in driving apparent uWUE variations over time, but its role differs for the two constituent components: potential uWUE and transpiration.

Computational methods to predict railcar response to track cross-level variations

DOT National Transportation Integrated Search

1976-09-01

The rocking response of railroad freight cars to track cross-level variations is studied using: (1) a reduced complexity digital simulation model, and (2) a quasi-linear describing function analysis. The reduced complexity digital simulation model em...

An in vitro simulation model to assess the severity of edge loading and wear, due to variations in component positioning in hip joint replacements.

PubMed

O'Dwyer Lancaster-Jones, O; Williams, S; Jennings, L M; Thompson, J; Isaac, G H; Fisher, J; Al-Hajjar, M

2017-09-23

The aim of this study was to develop a preclinical in vitro method to predict the occurrence and severity of edge loading condition associated with the dynamic separation of the centres of the head and cup (in the absence of impingement) for variations in surgical positioning of the cup. Specifically, this study investigated the effect of both the variations in the medial-lateral translational mismatch between the centres of the femoral head and acetabular cup and the variations in the cup inclination angles on the occurrence and magnitude of the dynamic separation, the severity of edge loading, and the wear rate of ceramic-on-ceramic hip replacement bearings in a multi-station hip joint simulator during a walking gait cycle. An increased mismatch between the centres of rotation of the femoral head and acetabular cup resulted in an increased level of dynamic separation and an increase in the severity of edge loading condition which led to increased wear rate in ceramic-on-ceramic bearings. Additionally for a given translational mismatch, an increase in the cup inclination angle gave rise to increased dynamic separation, worst edge loading conditions, and increased wear. To reduce the occurrence and severity of edge loading, the relative positions (the mismatch) of the centres of rotation of the head and the cup should be considered alongside the rotational position of the acetabular cup. This study has considered the combination of mechanical and tribological factors for the first time in the medial-lateral axis only, involving one rotational angle (inclination) and one translational mismatch. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc.

Modeling the impact of bubbling bed hydrodynamics on tar yield and its fluctuations during biomass fast pyrolysis

DOE PAGES

Xiong, Qingang; Ramirez, Emilio; Pannala, Sreekanth; ...

2015-10-09

The impact of bubbling bed hydrodynamics on temporal variations in the exit tar yield for biomass fast pyrolysis was investigated using computational simulations of an experimental laboratory-scale reactor. A multi-fluid computational fluid dynamics model was employed to simulate the differential conservation equations in the reactor, and this was combined with a multi-component, multi-step pyrolysis kinetics scheme for biomass to account for chemical reactions. The predicted mean tar yields at the reactor exit appear to match corresponding experimental observations. Parametric studies predicted that increasing the fluidization velocity should improve the mean tar yield but increase its temporal variations. Increases in themore » mean tar yield coincide with reducing the diameter of sand particles or increasing the initial sand bed height. However, trends in tar yield variability are more complex than the trends in mean yield. The standard deviation in tar yield reaches a maximum with changes in sand particle size. As a result, the standard deviation in tar yield increases with the increases in initial bed height in freely bubbling state, while reaches a maximum in slugging state.« less

Sleep Quality but Not Quantity Altered With a Change in Training Environment in Elite Australian Rules Football Players.

PubMed

Pitchford, Nathan W; Robertson, Sam J; Sargent, Charli; Cordy, Justin; Bishop, David J; Bartlett, Jonathan D

2017-01-01

To assess the effects of a change in training environment on the sleep characteristics of elite Australian Rules football (AF) players. In an observational crossover trial, 19 elite AF players had time in bed (TIB), total sleep time (TST), sleep efficiency (SE), and wake after sleep onset (WASO) assessed using wristwatch activity devices and subjective sleep diaries across 8-d home and camp periods. Repeated-measures ANOVA determined mean differences in sleep, training load (session rating of perceived exertion [RPE]), and environment. Pearson product-moment correlations, controlling for repeated observations on individuals, were used to assess the relationship between changes in sleep characteristics at home and camp. Cohen effect sizes (d) were calculated using individual means. On camp TIB (+34 min) and WASO (+26 min) increased compared with home. However, TST was similar between home and camp, significantly reducing camp SE (-5.82%). Individually, there were strong negative correlations for TIB and WASO (r = -.75 and r = -.72, respectively) and a moderate negative correlation for SE (r = -.46) between home and relative changes on camp. Camp increased the relationship between individual s-RPE variation and TST variation compared with home (increased load r = -.367 vs .051, reduced load r = .319 vs -.033, camp vs home respectively). Camp compromised sleep quality due to significantly increased TIB without increased TST. Individually, AF players with higher home SE experienced greater reductions in SE on camp. Together, this emphasizes the importance of individualized interventions for elite team-sport athletes when traveling and/or changing environments.

Seasonal variation in surface fuel moisture between unthinned and thinned mixed conifer forest, northern California, USA

Treesearch

Becky L. Estes; Eric E. Knapp; Carl N. Skinner; Fabian C. C. Uzoh

2012-01-01

Reducing stand density is often used as a tool for mitigating the risk of high-intensity crown fires. However, concern has been expressed that opening stands might lead to greater drying of surface fuels, contributing to increased fire risk. The objective of this study was to determine whether woody fuel moisture differed between unthinned and thinned mixed-conifer...

Laser cutting of various materials: Kerf width size analysis and life cycle assessment of cutting process

NASA Astrophysics Data System (ADS)

Yilbas, Bekir Sami; Shaukat, Mian Mobeen; Ashraf, Farhan

2017-08-01

Laser cutting of various materials including Ti-6Al-4V alloy, steel 304, Inconel 625, and alumina is carried out to assess the kerf width size variation along the cut section. The life cycle assessment is carried out to determine the environmental impact of the laser cutting in terms of the material waste during the cutting process. The kerf width size is formulated and predicted using the lump parameter analysis and it is measured from the experiments. The influence of laser output power and laser cutting speed on the kerf width size variation is analyzed using the analytical tools including scanning electron and optical microscopes. In the experiments, high pressure nitrogen assisting gas is used to prevent oxidation reactions in the cutting section. It is found that the kerf width size predicted from the lump parameter analysis agrees well with the experimental data. The kerf width size variation increases with increasing laser output power. However, this behavior reverses with increasing laser cutting speed. The life cycle assessment reveals that material selection for laser cutting is critical for the environmental protection point of view. Inconel 625 contributes the most to the environmental damages; however, recycling of the waste of the laser cutting reduces this contribution.

Variations in risk and protective factors for life satisfaction and mental wellbeing with deprivation: a cross-sectional study.

PubMed

Bellis, Mark A; Lowey, Helen; Hughes, Karen; Deacon, Lynn; Stansfield, Jude; Perkins, Clare

2012-07-02

Improving life satisfaction (LS) and mental wellbeing (MWB) is important for better public health. Like other health issues, LS and MWB are closely related to deprivation (i.e. lack of resources). Developing public health measures that reduce inequalities in wellbeing requires an understanding of how factors associated with high and low LS and MWB vary with deprivation. Here, we examine such variations and explore which public health measures are likely to improve wellbeing while reducing related inequalities. A self-administered questionnaire measuring LS and MWB was used with a cross-sectional sample of adults from the North West of England (n = 15,228). Within deprivation tertiles, analyses examined how demographics, health status, employment, relationships and behaviours (alcohol, tobacco, physical exercise) were associated with LS and MWB. Deprivation was strongly related to low LS and MWB with, for instance, 17.1% of the most deprived tertile having low LS compared to 8.9% in the most affluent. After controlling for confounders, across all deprivation tertiles, better self-assessed health status and being in a relationship were protective against low LS and MWB. Unemployment increased risks of low LS across all tertiles but only risks of low MWB in the deprived tertile. For this tertile, South Asian ethnicity and higher levels of exercise were protective against low MWB. In the middle tertile retired individuals had a reduced risk of low MWB and an increased chance of high LS even in comparison to those in employment. Alcohol's impact on LS was limited to the most deprived tertile where heavy drinkers were at most risk of poor outcomes. In this study, positive outcomes for LS and MWB were strongly associated with lower deprivation and good health status. Public health measures already developed to promote these issues are likely to improve LS and MWB. Efforts to increase engagement in exercise are also likely to have positive impacts, particularly in deprived communities. The development of future initiatives that address LS and MWB must take account of variations in their risk and protective factors at different levels of deprivation.

Van der Waals pressure sensors using reduced graphene oxide composites

NASA Astrophysics Data System (ADS)

Jung, Ju Ra; Ahn, Sung Il

2018-04-01

Reduced graphene oxide (RGO) films intercalated with various polymers were fabricated by reaction-based self-assembly, and their characteristics as vacuum pressure sensors based on van der Waals interactions were studied. At low temperature, the electrical resistances of the samples decrease linearly with increasing vacuum pressure, whereas at high temperature the variation of the electrical resistance shows secondary order curves. Among all samples, the poly vinyl alcohol intercalated RGO shows the highest sensitivity, being almost two times more sensitive than reference RGO. All samples show almost the same signal for repetitive sudden pressure changes, indicating reasonable reproducibility and durability.

The Longitudinal Stability of Flying Boats as Determined by Tests of Models in the NACA Tank II : Effect of Variations in Form of Hull on Longitudinal Stability

NASA Technical Reports Server (NTRS)

Olson, Roland E.; Truscott, Starr

1942-01-01

Data taken from tests at constant speed to establish trim limits of stability, tests at accelerated speeds to determine stable limits of center of gravity shift, and tests at decelerated speeds to obtain landing characteristics of several model hull forms were used to establish hull design effect on longitudinal stability of porpoising. Results show a reduction of dead rise angle as being the only investigated factor reducing low trim limit. Various methods of reducing afterbody interference increased upper trim limit

Radiative-photochemical response of the mesosphere to dynamical forcing

NASA Technical Reports Server (NTRS)

Frederick, J. E.

1981-01-01

Combination of the chemical continuity equation for odd oxygen with the second law of thermodynamics yields analytic solutions which describe the coupled behavior of temperature and ozone perturbations in response to an externally specified forcing. The results appear in a form which allows easy physical interpretation of the coupling between radiative and photochemical processes. When the forcing is chosen to mimic a planetary scale wave, the theory shows that photochemical acceleration of radiative damping reduces the amplitude of the temperature perturbation by an amount which increases with the wave period. Although ozone fluctuations are anti-correlated with those in temperature, minima in ozone do not coincide exactly in longitude with temperature maxima. The percentage variation in ozone increases upward and is always larger than that in temperature at the same pressure. This demonstrates that variations in ozone on constant pressure surfaces may serve as a sensitive indicator of wave activity in the mesosphere.

The effects of season and sand mining activities on thermal regime and water quality in a large shallow tropical lake.

PubMed

Sharip, Zati; Zaki, Ahmad Taqiyuddin Ahmad

2014-08-01

Thermal structure and water quality in a large and shallow lake in Malaysia were studied between January 2012 and June 2013 in order to understand variations in relation to water level fluctuations and in-stream mining activities. Environmental variables, namely temperature, turbidity, dissolved oxygen, pH, electrical conductivity, chlorophyll-A and transparency, were measured using a multi-parameter probe and a Secchi disk. Measurements of environmental variables were performed at 0.1 m intervals from the surface to the bottom of the lake during the dry and wet seasons. High water level and strong solar radiation increased temperature stratification. River discharges during the wet season, and unsustainable sand mining activities led to an increased turbidity exceeding 100 NTU, and reduced transparency, which changed the temperature variation and subsequently altered the water quality pattern.

A mechanism for inducing climatic variations through the stratosphere - Screening of cosmic rays by solar and terrestrial magnetic fields

NASA Technical Reports Server (NTRS)

Chamberlain, J. W.

1977-01-01

The ability of heliomagnetic and geomagnetic fields to bring about climatic variations of long period is examined theoretically. A chemical relationship between low-energy cosmic rays and ozone balance in the stratosphere is sought as a crucial clue to historical changes in earth climate. A perturbation analysis is developed to arrive at zone depletion and reduction of stratospheric solar heating resulting from increased NOx concentration; temperature feedback and opacity feedback are allowed for. Modulation of galactic cosmic-radiation fluxes and ozone destruction in the stratosphere, colder surface temperatures associated with reduced magnetic shielding, and redistribution with height of total ozone decrease are explored.

Variation of the shower lateral spread with air temperature at the ground

NASA Astrophysics Data System (ADS)

Wilczyńska, B.; Engel, R.; Homola, P.; Keilhauer, B.; Klages, H.; Pękala, J.; Wilczyński, H.

The vertical profile of air density at a given site varies considerably with time. Well understood seasonal differences are present, but sizeable effects on shorter time scales, like day to night or day to day variations, are also observed. In consequence, the Moliere radius changes, influencing the lateral distribution of particles in the air showers and therefore may influence the shower detection in surface detector arrays. In air shower reconstruction, usually seasonal average profiles of the atmosphere are used, because local daily measurements of the profile are rarely available. Therefore, the daily fluctuations of the atmosphere are not accounted for. This simplification increases the inaccuracies of shower reconstruction. We show that a universal correlation exists between the ground temperature and the shape of the atmospheric profile, up to altitudes of several kilometers, hence providing a method to reduce inaccuracies in shower reconstruction due to weather variation.

Variability in sperm form and function in the context of sperm competition risk in two Tupinambis lizards

PubMed Central

Blengini, Cecilia S; Sergio, Naretto; Gabriela, Cardozo; Giojalas, Laura C; Margarita, Chiaraviglio

2014-01-01

In polyandrous species, sperm morphometry and sperm velocity are under strong sexual selection. Although several hypotheses have been proposed to explain the role of sperm competition in sperm trait variation, this aspect is still poorly understood. It has been suggested that an increase in sperm competition pressure could reduce sperm size variation or produce a diversity of sperm to maximize male fertilization success. We aim at elucidating the variability of sperm morphometric traits and velocity in two Tupinambis lizards in the context of sperm competition risk. Sperm traits showed substantial variation at all levels examined: between species, among males within species, and within the ejaculate of individual males. Sperm velocity was found to be positively correlated with flagellum: midpiece ratio, with relatively longer flagella associated with faster sperm. Our results document high variability in sperm form and function in lizards. PMID:25505535

Variation of high-power aluminum-wire array Z-pinch dynamics with wire number, load mass, and array radius

NASA Astrophysics Data System (ADS)

Sanford, T. W. L.; Mock, R. C.; Marder, B. M.; Nash, T. J.; Spielman, R. B.; Peterson, D. L.; Roderick, N. F.; Hammer, J. H.; De Groot, J. S.; Mosher, D.; Whitney, K. G.; Apruzese, J. P.

1997-05-01

A systematic study of annular aluminum-wire z-pinches on the Saturn accelerator shows that the quality of the implosion, (as measured by the radial convergence, the radiated energy, pulse width, and power), increases with wire number. Radiation magnetohydrodynamic (RMHC) xy simulations suggest that the implosion transitions from that of individual wire plasmas to that of a continuous plasma shell when the interwire spacing is reduced below ˜1.4 mm. In this "plasma-shell regime," many of the global radiation and plasma characteristics are in agreement with those simulated by 2D-RMHC rz simulations. In this regime, measured changes in the radiation pulse width with variations in load mass and array radius are consistent with the simulations and are explained by the development of 2D fluid motion in the rz plane. Associated variations in the K-shell yield are qualitatively explained by simple radiation-scaling models.

Being fat and smart: A comparative analysis of the fat-brain trade-off in mammals.

PubMed

Heldstab, Sandra A; van Schaik, Carel P; Isler, Karin

2016-11-01

Humans stand out among non-aquatic mammals by having both an extremely large brain and a relatively large amount of body fat. To understand the evolution of this human peculiarity we report a phylogenetic comparative study of 120 mammalian species, including 30 primates, using seasonal variation in adult body mass as a proxy of the tendency to store fat. Species that rely on storing fat to survive lean periods are expected to be less active because of higher costs of locomotion and have increased predation risk due to reduced agility. Because a fat-storage strategy reduces the net cognitive benefit of a large brain without reducing its cost, such species should be less likely to evolve a larger brain than non-fat-storing species. We therefore predict that the two strategies to buffer food shortages (storing body fat and cognitive flexibility) are compensatory, and therefore predict negative co-evolution between relative brain size and seasonal variation in body mass. This trade-off is expected to be stronger in predominantly arboreal species than in more terrestrial ones, as the cost of transporting additional adipose depots is higher for climbing than for horizontal locomotion. We did, indeed, find a significant negative correlation between brain size and coefficient of variation (CV) in body mass in both sexes for the subsample of arboreal species, both in all mammals and within primates. In predominantly terrestrial species, in contrast, this correlation was not significant. We therefore suggest that the adoption of habitually terrestrial locomotor habits, accompanied by a reduced reliance on climbing, has allowed for a primate of our body size the unique human combination of unusually large brains and unusually large adipose depots. Copyright © 2016 Elsevier Ltd. All rights reserved.

Concordance of nuclear and mitochondrial DNA markers in detecting a founder event in Lake Clark sockeye salmon

USGS Publications Warehouse

Ramstad, Kristina M.; Woody, Carol Ann; Habicht, Chris; Sage, G. Kevin; Seeb, James E.; Allendorf, Fred W.

2007-01-01

Genetic bottleneck effects can reduce genetic variation, persistence probability, and evolutionary potential of populations. Previous microsatellite analysis suggested a bottleneck associated with a common founding of sock-eye salmon Oncorhynchus nerka populations of Lake Clark, Alaska, about 100 to 400 generations ago. The common foundingevent occurred after the last glacial recession and resulted in reduced allelic diversity and strong divergence of Lake Clarksockeye salmon relative to neighboring Six Mile Lake and LakeIliamna populations. Here we used two additional genetic marker types (allozymes and mtDNA) to examine these patterns further. Allozyme and mtDNA results were congruent with the microsatellite data in suggesting a common founder event in LakeClark sockeye salmon and confirmed the divergence of Lake Clarkpopulations from neighboring Six Mile Lake and Lake Iliamna populations. The use of multiple marker types provided better understanding of the bottleneck in Lake Clark. For example, the Sucker Bay Lake population had an exceptionally severe reduction in allelic diversity at microsatellite loci, but not at mtDNA. This suggests that the reduced microsatellite variation in Sucker Bay Lake fish is due to consistently smaller effective population size than other Lake Clark populations, rather than a more acute or additional bottleneck since founding. Caution is urged in using reduced heterozygosity as a measure of genetic bottleneck effects because stochastic variance among loci resulted in an overall increase in allozyme heterozygosity within bottlenecked Lake Clark populations. However, heterozygosity excess, which assesses heterozygosity relative to allelic variation, detected genetic bottleneck effects in both allozyme and microsatellite loci. 

Population-Based Analysis and Projections of Liver Supply Under Redistricting.

PubMed

Parikh, Neehar D; Marrero, Wesley J; Sonnenday, Christopher J; Lok, Anna S; Hutton, David W; Lavieri, Mariel S

2017-09-01

To reduce the geographic heterogeneity in liver transplant allocation, the United Network of Organ Sharing has proposed redistricting, which is impacted by both donor supply and liver transplantation demand. We aimed to determine the impact of demographic changes on the redistricting proposal and characterize causes behind geographic heterogeneity in donor supply. We analyzed adult donors from 2002 to 2014 from the United Network of Organ Sharing database and calculated regional liver donation and utilization stratified by age, race, and body mass index. We used US population data to make regional projections of available donors from 2016 to 2025, incorporating the proposed 8-region redistricting plan. We used donors/100 000 population age 18 to 84 years (D/100K) as a measure of equity. We calculated a coefficient of variation (standard deviation/mean) for each regional model. We performed an exploratory analysis where we used national rates of donation, utilization and both for each regional model. The overall projected D/100K will decrease from 2.53 to 2.49 from 2016 to 2025. The coefficient of variation in 2016 is expected to be 20.3% in the 11-region model and 13.2% in the 8-region model. We found that standardizing regional donation and utilization rates would reduce geographic heterogeneity to 4.9% in the 8-region model and 4.6% in the 11-region model. The 8-region allocation model will reduce geographic variation in donor supply to a significant extent; however, we project that geographic disparity will marginally increase over time. Though challenging, interventions to better standardize donation and utilization rates would be impactful in reducing geographic heterogeneity in organ supply.

Characterization of Greater Middle Eastern genetic variation for enhanced disease gene discovery.

PubMed

Scott, Eric M; Halees, Anason; Itan, Yuval; Spencer, Emily G; He, Yupeng; Azab, Mostafa Abdellateef; Gabriel, Stacey B; Belkadi, Aziz; Boisson, Bertrand; Abel, Laurent; Clark, Andrew G; Alkuraya, Fowzan S; Casanova, Jean-Laurent; Gleeson, Joseph G

2016-09-01

The Greater Middle East (GME) has been a central hub of human migration and population admixture. The tradition of consanguinity, variably practiced in the Persian Gulf region, North Africa, and Central Asia, has resulted in an elevated burden of recessive disease. Here we generated a whole-exome GME variome from 1,111 unrelated subjects. We detected substantial diversity and admixture in continental and subregional populations, corresponding to several ancient founder populations with little evidence of bottlenecks. Measured consanguinity rates were an order of magnitude above those in other sampled populations, and the GME population exhibited an increased burden of runs of homozygosity (ROHs) but showed no evidence for reduced burden of deleterious variation due to classically theorized 'genetic purging'. Applying this database to unsolved recessive conditions in the GME population reduced the number of potential disease-causing variants by four- to sevenfold. These results show variegated genetic architecture in GME populations and support future human genetic discoveries in Mendelian and population genetics.

Characterization of Greater Middle Eastern genetic variation for enhanced disease gene discovery

PubMed Central

Scott, Eric M.; Halees, Anason; Itan, Yuval; Spencer, Emily G.; He, Yupeng; Azab, Mostafa Abdellateef; Gabriel, Stacey B.; Belkadi, Aziz; Boisson, Bertrand; Abel, Laurent; Clark, Andrew G.; Alkuraya, Fowzan S.; Casanova, Jean-Laurent; Gleeson, Joseph G.

2016-01-01

The Greater Middle East (GME) has been a central hub of human migration and population admixture. The tradition of consanguinity, variably practiced in the Gulf region, North Africa, and Central Asia 1–3, has resulted in an elevated burden of recessive disease4. Here we generated a whole exome GME variome from 1,111 unrelated subjects. We detected substantial diversity from sub-geographies, continental and subregional admixture, several ancient founder populations with little evidence of bottlenecks. Measured consanguinity was an order-of-magnitude above that of other sampled populations, and included an increased burden of runs of homozygosity (ROH), but no evidence for reduced burden of deleterious variation due to classically theorized ‘genetic purging’. Applying this database to unsolved GME recessive conditions reduced the number of potential disease-causing variants by 4–7-fold. These results reveal the variegated GME genetic architecture and support future human genetic discoveries in Mendelian and population genetics. PMID:27428751

Way-Scaling to Reduce Power of Cache with Delay Variation

NASA Astrophysics Data System (ADS)

Goudarzi, Maziar; Matsumura, Tadayuki; Ishihara, Tohru

The share of leakage in cache power consumption increases with technology scaling. Choosing a higher threshold voltage (Vth) and/or gate-oxide thickness (Tox) for cache transistors improves leakage, but impacts cell delay. We show that due to uncorrelated random within-die delay variation, only some (not all) of cells actually violate the cache delay after the above change. We propose to add a spare cache way to replace delay-violating cache-lines separately in each cache-set. By SPICE and gate-level simulations in a commercial 90nm process, we show that choosing higher Vth, Tox and adding one spare way to a 4-way 16KB cache reduces leakage power by 42%, which depending on the share of leakage in total cache power, gives up to 22.59% and 41.37% reduction of total energy respectively in L1 instruction- and L2 unified-cache with a negligible delay penalty, but without sacrificing cache capacity or timing-yield.

The Impacts of Bias in Cloud-Radiation-Dynamics Interactions on Central Pacific Seasonal and El Niño Simulations in Contemporary GCMs

NASA Astrophysics Data System (ADS)

Li, J.-L. F.; Suhas, E.; Richardson, Mark; Lee, Wei-Liang; Wang, Yi-Hui; Yu, Jia-Yuh; Lee, Tong; Fetzer, Eric; Stephens, Graeme; Shen, Min-Hua

2018-02-01

Most of the global climate models (GCMs) in the Coupled Model Intercomparison Project, phase 5 do not include precipitating ice (aka falling snow) in their radiation calculations. We examine the importance of the radiative effects of precipitating ice on simulated surface wind stress and sea surface temperatures (SSTs) in terms of seasonal variation and in the evolution of central Pacific El Niño (CP-El Niño) events. Using controlled simulations with the CESM1 model, we show that the exclusion of precipitating ice radiative effects generates a persistent excessive upper-level radiative cooling and an increasingly unstable atmosphere over convective regions such as the western Pacific and tropical convergence zones. The invigorated convection leads to persistent anomalous low-level outflows which weaken the easterly trade winds, reducing upper-ocean mixing and leading to a positive SST bias in the model mean state. In CP-El Niño events, this means that outflow from the modeled convection in the central Pacific reduces winds to the east, allowing unrealistic eastward propagation of warm SST anomalies following the peak in CP-El Niño activity. Including the radiative effects of precipitating ice reduces these model biases and improves the simulated life cycle of the CP-El Niño. Improved simulations of present-day tropical seasonal variations and CP-El Niño events would increase the confidence in simulating their future behavior.

From 'solution shop' model to 'focused factory' in hospital surgery: increasing care value and predictability.

PubMed

Cook, David; Thompson, Jeffrey E; Habermann, Elizabeth B; Visscher, Sue L; Dearani, Joseph A; Roger, Veronique L; Borah, Bijan J

2014-05-01

The full-service US hospital has been described organizationally as a "solution shop," in which medical problems are assumed to be unstructured and to require expert physicians to determine each course of care. If universally applied, this model contributes to unwarranted variation in care, which leads to lower quality and higher costs. We purposely disrupted the adult cardiac surgical practice that we led at Mayo Clinic, in Rochester, Minnesota, by creating a "focused factory" model (characterized by a uniform approach to delivering a limited set of high-quality products) within the practice's solution shop. Key elements of implementing the new model were mapping the care process, segmenting the patient population, using information technology to communicate clearly defined expectations, and empowering nonphysician providers at the bedside. Using a set of criteria, we determined that the focused-factory model was appropriate for 67 percent of cardiac surgical patients. We found that implementation of the model reduced resource use, length-of-stay, and cost. Variation was markedly reduced, and outcomes were improved. Assigning patients to different care models increases care value and the predictability of care process, outcomes, and costs while preserving (in a lesser clinical footprint) the strengths of the solution shop. We conclude that creating a focused-factory model within a solution shop, by applying industrial engineering principles and health information technology tools and changing the model of work, is very effective in both improving quality and reducing costs.

Flexible, multi-measurement guided wave damage detection under varying temperatures

NASA Astrophysics Data System (ADS)

Douglass, Alexander C. S.; Harley, Joel B.

2018-04-01

Temperature compensation in structural health monitoring helps identify damage in a structure by removing data variations due to environmental conditions, such as temperature. Stretch-based methods are one of the most commonly used temperature compensation methods. To account for variations in temperature, stretch-based methods optimally stretch signals in time to optimally match a measurement to a baseline. All of the data is then compared with the single baseline to determine the presence of damage. Yet, for these methods to be effective, the measurement and the baseline must satisfy the inherent assumptions of the temperature compensation method. In many scenarios, these assumptions are wrong, the methods generate error, and damage detection fails. To improve damage detection, a multi-measurement damage detection method is introduced. By using each measurement in the dataset as a baseline, error caused by imperfect temperature compensation is reduced. The multi-measurement method increases the detection effectiveness of our damage metric, or damage indicator, over time and reduces the presence of additional peaks caused by temperature that could be mistaken for damage. By using many baselines, the variance of the damage indicator is reduced and the effects from damage are amplified. Notably, the multi-measurement improves damage detection over single-measurement methods. This is demonstrated through an increase in the maximum of our damage signature from 0.55 to 0.95 (where large values, up to a maximum of one, represent a statistically significant change in the data due to damage).

Seasonality of service provision in hip and knee surgery: a possible contributor to waiting times? A time series analysis.

PubMed

Upshur, Ross E G; Moineddin, Rahim; Crighton, Eric J; Mamdani, Muhammad

2006-03-01

The question of how best to reduce waiting times for health care, particularly surgical procedures such as hip and knee replacements is among the most pressing concern of the Canadian health care system. The objective of this study was to test the hypothesis that significant seasonal variation exists in the performance of hip and knee replacement surgery in the province of Ontario. We performed a retrospective, cross-sectional time series analysis examining all hip and knee replacement surgeries in people over the age of 65 in the province of Ontario, Canada between 1992 and 2002. The main outcome measure was monthly hospitalization rates per 100,000 population for all hip and knee replacements. There was a marked increase in the rate of hip and knee replacement surgery over the 10-year period as well as an increasing seasonal variation in surgeries. Highly significant (Fisher Kappa = 16.05, p < 0.01; Bartlett-Kolmogorov-Smirnov Test = 0.31, p < 0.01) and strong (R2Autoreg = 0.85) seasonality was identified in the data. Holidays and utilization caps appear to exert a significant influence on the rate of service provision. It is expected that waiting times for hip and knee replacement could be reduced by reducing seasonal fluctuations in service provision and benchmarking services to peak delivery. The results highlight the importance of system behaviour in seasonal fluctuation of service delivery.

Seasonality of service provision in hip and knee surgery: A possible contributor to waiting times? A time series analysis

PubMed Central

Upshur, Ross EG; Moineddin, Rahim; Crighton, Eric J; Mamdani, Muhammad

2006-01-01

Background The question of how best to reduce waiting times for health care, particularly surgical procedures such as hip and knee replacements is among the most pressing concern of the Canadian health care system. The objective of this study was to test the hypothesis that significant seasonal variation exists in the performance of hip and knee replacement surgery in the province of Ontario. Methods We performed a retrospective, cross-sectional time series analysis examining all hip and knee replacement surgeries in people over the age of 65 in the province of Ontario, Canada between 1992 and 2002. The main outcome measure was monthly hospitalization rates per 100 000 population for all hip and knee replacements. Results There was a marked increase in the rate of hip and knee replacement surgery over the 10-year period as well as an increasing seasonal variation in surgeries. Highly significant (Fisher Kappa = 16.05, p < 0.01; Bartlett-Kolmogorov-Smirnov Test = 0.31, p < 0.01) and strong (R2Autoreg = 0.85) seasonality was identified in the data. Conclusion Holidays and utilization caps appear to exert a significant influence on the rate of service provision. It is expected that waiting times for hip and knee replacement could be reduced by reducing seasonal fluctuations in service provision and benchmarking services to peak delivery. The results highlight the importance of system behaviour in seasonal fluctuation of service delivery. PMID:16509992

Predictive modeling and reducing cyclic variability in autoignition engines

DOEpatents

Hellstrom, Erik; Stefanopoulou, Anna; Jiang, Li; Larimore, Jacob

2016-08-30

Methods and systems are provided for controlling a vehicle engine to reduce cycle-to-cycle combustion variation. A predictive model is applied to predict cycle-to-cycle combustion behavior of an engine based on observed engine performance variables. Conditions are identified, based on the predicted cycle-to-cycle combustion behavior, that indicate high cycle-to-cycle combustion variation. Corrective measures are then applied to prevent the predicted high cycle-to-cycle combustion variation.

Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature

DOEpatents

Kelledes, William L.; St. John, Don K.

1992-01-01

The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.

The Sensitivity of U.S. Surface Ozone Formation to NOx, and VOCs as Viewed from Space

NASA Technical Reports Server (NTRS)

Duncan, Bryan N.; Yoshida, Yasuko; Sillman, Sanford; Retscher, Christian; Pickering, Kenneth E.; Martin, Randall V.; Celarier, Edward A.

2009-01-01

We investigated variations in the sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NO(x)) as inferred from the ratio of tropospheric columns of formaldehyde and nitrogen dioxide from the Aura Ozone Monitoring Instrument (OMI). The data indicate that ozone formation became: 1. more sensitive to NO(x) over most of the U.S, from 2005 to 2007 because of substantial decreases in NO(x) emissions primarily from stationary sources, and 2. more sensitive to NO(x) with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. Based on our interpretation of the data, current strategies implemented to reduce unhealthy levels of surface ozone should focus more on reducing NO(x) emissions, except in some downtown areas which have historically benefited from reductions in VOC emissions.

Paleoceanographic Changes during the Past 95000 Years from the Indian Sector of the Southern Ocean

NASA Astrophysics Data System (ADS)

Manoj, M. C.; Meloth, T.; Mohan, R.

2012-12-01

High-resolution planktic/benthic foraminiferal stable isotope and mean sortable silt records in a sediment core (SK200/22a) from the sub-Antarctic regime of the Indian sector of Southern Ocean depict the variations in surface and deep water hydrography during the past 95,000 years. The δ18O records of shallow- and deep-dwelling planktonic foraminiferal species (Neogloboquadrina pachyderma, Globigerina bulloides and Globorotalia inflata), primarily reflects the changes in upper water column characteristics. The δ18O records revealed the presence of the Antarctic Cold Reversal and the timing of the variability in major surface warming events appears in phase with the Antarctic temperature variations at the millennial time scale. Comparison between the proxies of sea surface conditions like planktonic δ18O and productivity proxies like carbonate and biogenic opal content in the core indicate that millennial scale sea surface warming fluctuated with productivity. The marine isotopic stage (MIS) 1 and MIS2 are characterized by near constant variations in mean sortable silt values, negating any significant changes in the deep water flow during these periods. The MIS 3 - MIS 5 periods were characterized by a general increase in mean sortable silt value, suggesting a strengthening of bottom-current activity that triggered winnowing at these periods. This is supported by the low δ13C records of epibenthic Cibicidoides wuellerstorfi during the glacials and some parts of MIS3 and MIS 5, confirming older nutrient-rich and poorly ventilated southern sourced deep waters at these periods. The termination I is marked by decrease in flow speed and an increase in the C. wuellerstorfi δ13C values. Comparison of mean sortable silt and C. wuellerstorfi δ13C record with the Antarctic ice core records reveal that pulses of reduced bottom water flow of Circumpolar Deep Water/North Atlantic Deep Water are synchronous with the Antarctic warming events. The decreased flow speed during the Antarctic warm events may be due to the lower production rate of southern-sourced water or reduced density, leading to reduced geostrophic flow. During the cold phases of the Antarctic climate, enhanced southern westerly wind transport caused increased sea-ice export leading to increase in density of southern-sourced water.

Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature.

PubMed

Tattersall, Glenn J; Roussel, Damien; Voituron, Yann; Teulier, Loïc

2016-09-28

This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (5°C) or thermoneutrality (TN) (25°C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temperature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term variations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energetic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting. © 2016 The Author(s).

Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature

PubMed Central

2016-01-01

This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (5°C) or thermoneutrality (TN) (25°C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temperature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term variations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energetic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting. PMID:27655770

Uncertainty Categorization, Modeling, and Management for Regional Water Supply Planning

NASA Astrophysics Data System (ADS)

Fletcher, S.; Strzepek, K. M.; AlSaati, A.; Alhassan, A.

2016-12-01

Many water planners face increased pressure on water supply systems from growing demands, variability in supply and a changing climate. Short-term variation in water availability and demand; long-term uncertainty in climate, groundwater storage, and sectoral competition for water; and varying stakeholder perspectives on the impacts of water shortages make it difficult to assess the necessity of expensive infrastructure investments. We categorize these uncertainties on two dimensions: whether they are the result of stochastic variation or epistemic uncertainty, and whether the uncertainties can be described probabilistically or are deep uncertainties whose likelihood is unknown. We develop a decision framework that combines simulation for probabilistic uncertainty, sensitivity analysis for deep uncertainty and Bayesian decision analysis for uncertainties that are reduced over time with additional information. We apply this framework to two contrasting case studies - drought preparedness in Melbourne, Australia and fossil groundwater depletion in Riyadh, Saudi Arabia - to assess the impacts of different types of uncertainty on infrastructure decisions. Melbourne's water supply system relies on surface water, which is impacted by natural variation in rainfall, and a market-based system for managing water rights. Our results show that small, flexible investment increases can mitigate shortage risk considerably at reduced cost. Riyadh, by contrast, relies primarily on desalination for municipal use and fossil groundwater for agriculture, and a centralized planner makes allocation decisions. Poor regional groundwater measurement makes it difficult to know when groundwater pumping will become uneconomical, resulting in epistemic uncertainty. However, collecting more data can reduce the uncertainty, suggesting the need for different uncertainty modeling and management strategies in Riyadh than in Melbourne. We will categorize the two systems and propose appropriate decision making under uncertainty methods from the state of the art. We will compare the efficiency of alternative approaches to the two case studies. Finally, we will present a hybrid decision analytic tool to address the synthesis of uncertainties.

The large area crop inventory experiment: A major demonstration of space remote sensing

NASA Technical Reports Server (NTRS)

Macdonald, R. B.; Hall, F. G.

1977-01-01

Strategies are presented in agricultural technology to increase the resistance of crops to a wider range of meteorological conditions in order to reduce year-to-year variations in crop production. Uncertainties in agricultral production, together with the consumer demands of an increasing world population, have greatly intensified the need for early and accurate annual global crop production forecasts. These forecasts must predict fluctuation with an accuracy, timeliness and known reliability sufficient to permit necessary social and economic adjustments, with as much advance warning as possible.

Near-surface density profiling of Fe ion irradiated Si (100) using extremely asymmetric x-ray diffraction by variation of the wavelength

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

Khanbabaee, B., E-mail: khanbabaee@physik.uni-siegen.de; Pietsch, U.; Facsko, S.

2014-10-20

In this work, we report on correlations between surface density variations and ion parameters during ion beam-induced surface patterning process. The near-surface density variations of irradiated Si(100) surfaces were investigated after off-normal irradiation with 5 keV Fe ions at different fluences. In order to reduce the x-ray probing depth to a thickness below 5 nm, the extremely asymmetrical x-ray diffraction by variation of wavelength was applied, exploiting x-ray refraction at the air-sample interface. Depth profiling was achieved by measuring x-ray rocking curves as function of varying wavelengths providing incidence angles down to 0°. The density variation was extracted from the deviationsmore » from kinematical Bragg angle at grazing incidence angles due to refraction of the x-ray beam at the air-sample interface. The simulations based on the dynamical theory of x-ray diffraction revealed that while a net near-surface density decreases with increasing ion fluence which is accompanied by surface patterning, there is a certain threshold of ion fluence to surface density modulation. Our finding suggests that the surface density variation can be relevant with the mechanism of pattern formation.« less

Evolutionary and ecological consequences of multiscale variation in pollen receipt for seed production.

PubMed

Schreiber, Sebastian J; Rosenheim, Jay A; Williams, Neal W; Harder, Lawrence D

2015-01-01

Variation in resource availability can select for traits that reduce the negative impacts of this variability on mean fitness. Such selection may be particularly potent for seed production in flowering plants, as they often experience variation in pollen receipt among individuals and among flowers within individuals. Using analytically tractable models, we examine the optimal allocations for producing ovules, attracting pollen, and maturing seeds in deterministic and stochastic pollen environments. In deterministic environments, the optimal strategy attracts sufficient pollen to fertilize every ovule and mature every zygote into a seed. Stochastic environments select for allocations proportional to the risk of seed production being limited by zygotes or seed maturation. When producing an ovule is cheap and maturing a seed is expensive, among-plant variation selects for attracting more pollen at the expense of producing fewer ovules and having fewer resources for seed maturation. Despite this increased allocation, such populations are likely to be pollen limited. In contrast, within-plant variation generally selects for an overproduction of ovules and, to a lesser extent, pollen attraction. Such populations are likely to be resource limited and exhibit low seed-to-ovule ratios. These results highlight the importance of multiscale variation in the evolution and ecology of resource allocations.

Interannual variations in needle and sapwood traits of Pinus edulis branches under an experimental drought.

PubMed

Guérin, Marceau; Martin-Benito, Dario; von Arx, Georg; Andreu-Hayles, Laia; Griffin, Kevin L; Hamdan, Rayann; McDowell, Nate G; Muscarella, Robert; Pockman, William; Gentine, Pierre

2018-02-01

In the southwestern USA, recent large-scale die-offs of conifers raise the question of their resilience and mortality under droughts. To date, little is known about the interannual structural response to droughts. We hypothesized that piñon pines ( Pinus edulis ) respond to drought by reducing the drop of leaf water potential in branches from year to year through needle morphological adjustments. We tested our hypothesis using a 7-year experiment in central New Mexico with three watering treatments (irrigated, normal, and rain exclusion). We analyzed how variation in "evaporative structure" (needle length, stomatal diameter, stomatal density, stomatal conductance) responded to watering treatment and interannual climate variability. We further analyzed annual functional adjustments by comparing yearly addition of needle area (LA) with yearly addition of sapwood area (SA) and distance to tip ( d ), defining the yearly ratios SA:LA and SA:LA/ d . Needle length ( l ) increased with increasing winter and monsoon water supply, and showed more interannual variability when the soil was drier. Stomatal density increased with dryness, while stomatal diameter was reduced. As a result, anatomical maximal stomatal conductance was relatively invariant across treatments. SA:LA and SA:LA/ d showed significant differences across treatments and contrary to our expectation were lower with reduced water input. Within average precipitation ranges, the response of these ratios to soil moisture was similar across treatments. However, when extreme soil drought was combined with high VPD, needle length, SA:LA and SA:LA/ d became highly nonlinear, emphasizing the existence of a response threshold of combined high VPD and dry soil conditions. In new branch tissues, the response of annual functional ratios to water stress was immediate (same year) and does not attempt to reduce the drop of water potential. We suggest that unfavorable evaporative structural response to drought is compensated by dynamic stomatal control to maximize photosynthesis rates.

ITKids part II: variation of postures and muscle activity in children using different information and communication technologies.

PubMed

Ciccarelli, Marina; Straker, Leon; Mathiassen, Svend Erik; Pollock, Clare

2011-01-01

There are concerns that insufficient variation in postural and muscle activity associated with use of modern information and communication technology (ICT) presents a risk for musculoskeletal ill-health among school children. However, scientific knowledge on physical exposure variation in this group is limited. The purpose of this study was to quantify postures and muscle activity of school children using different types of ICT. Postures of the head, upper back and upper arm, and muscle activity of the right and left upper trapezius and right forearm extensors were measured over 10-12 hours in nine school children using different types of ICT at school and away-from-school. Variation in postures and muscle activity was quantified using two indices, EVA{sd} and APDF₉₀-₁₀. Paper-based (Old) ICT tasks produced postures that were less neutral but more variable than electronics-based (New ICT) and Non-ICT tasks. Non-ICT tasks involved mean postures similar to New ICT tasks, but with greater variation. Variation of muscle activity was similar between ICT types in the right and left upper trapezius muscles. Non-ICT tasks produced more muscle activity variation in the right forearm extensor group compared to New and Old ICT tasks. Different ICT tasks produce different degrees of variation in posture and muscle activity. Combining tasks that use different ICT may increase overall exposure variation. More research is needed to determine what degree of postural and muscle activity variation is associated with reduced risk of musculoskeletal ill-health.

Heat resistance throughout ontogeny: body size constrains thermal tolerance.

PubMed

Klockmann, Michael; Günter, Franziska; Fischer, Klaus

2017-02-01

Heat tolerance is a trait of paramount ecological importance and may determine a species' ability to cope with ongoing climate change. Although critical thermal limits have consequently received substantial attention in recent years, their potential variation throughout ontogeny remained largely neglected. We investigate whether such neglect may bias conclusions regarding a species' sensitivity to climate change. Using a tropical butterfly, we found that developmental stages clearly differed in heat tolerance. It was highest in pupae followed by larvae, adults and finally eggs and hatchlings. Strikingly, most of the variation found in thermal tolerance was explained by differences in body mass, which may thus impose a severe constraint on adaptive variation in stress tolerance. Furthermore, temperature acclimation was beneficial by increasing heat knock-down time and therefore immediate survival under heat stress, but it affected reproduction negatively. Extreme temperatures strongly reduced survival and subsequent reproductive success even in our highly plastic model organism, exemplifying the potentially dramatic impact of extreme weather events on biodiversity. We argue that predictions regarding a species' fate under changing environmental conditions should consider variation in thermal tolerance throughout ontogeny, variation in body mass and acclimation responses as important predictors of stress tolerance. © 2016 John Wiley & Sons Ltd.

DNA Dispose, but Subjects Decide. Learning and the Extended Synthesis.

PubMed

Lindholm, Markus

Adaptation by means of natural selection depends on the ability of populations to maintain variation in heritable traits. According to the Modern Synthesis this variation is sustained by mutations and genetic drift. Epigenetics, evodevo, niche construction and cultural factors have more recently been shown to contribute to heritable variation, however, leading an increasing number of biologists to call for an extended view of speciation and evolution. An additional common feature across the animal kingdom is learning, defined as the ability to change behavior according to novel experiences or skills. Learning constitutes an additional source for phenotypic variation, and change in behavior may induce long lasting shifts in fitness, and hence favor evolutionary novelties. Based on published studies, I demonstrate how learning about food, mate choice and habitats has contributed substantially to speciation in the canonical story of Darwin's finches on the Galapagos Islands. Learning cannot be reduced to genetics, because it demands decisions, which requires a subject. Evolutionary novelties may hence emerge both from shifts in allelic frequencies and from shifts in learned, subject driven behavior. The existence of two principally different sources of variation also prevents the Modern Synthesis from self-referring explanations.

Neither artificial light at night, anthropogenic noise nor distance from roads are associated with oxidative status of nestlings in an urban population of songbirds.

PubMed

Casasole, Giulia; Raap, Thomas; Costantini, David; AbdElgawad, Hamada; Asard, Han; Pinxten, Rianne; Eens, Marcel

2017-08-01

Increasing urbanization is responsible for road-related pollutants and causes an unprecedented increase in light and noise pollution, with potential detrimental effects for individual animals, communities and ecosystems. These stressors rarely act in isolation but studies dissecting the effects of these multiple stressors are lacking. Moreover, studies on urban stressors have mainly focused on adults, while exposure in early-life may be detrimental but is largely ignored. To fill this important knowledge gap, we studied if artificial light at night, anthropogenic noise and road-related pollution (using distance from roads as a proxy) explain variation in oxidative status in great tit nestlings (Parus major) in an urban population. Artificial light at night, anthropogenic noise and distance from roads were not associated with variation of the nine studied metrics of oxidative status (superoxide dismutase-SOD-, glutathione peroxidase-GPX, catalase-CAT-, non-enzymatic total antioxidant capacity-TAC-, reduced glutathione-GSH-, oxidized glutathione-GSSG-, ratio GSH/GSSG, protein carbonyls and thiobarbituric acid reactive substances-TBARS). Interestingly, for all oxidative status metrics, we found that there was more variation in oxidative status among individuals of the same nest compared to between different nests. We also showed an increase in protein carbonyls and a decrease of the ratio GSH/GSSG as the day advanced, and an increase of GPX when weather conditions deteriorated. Our study suggests that anthropogenic noise, artificial light at night and road-related pollution are not the most important sources of variation in oxidative status in great tit nestlings. It also highlights the importance of considering bleeding time and weather conditions in studies with free-living animals. Copyright © 2017. Published by Elsevier Inc.

Self-compensating design for reduction of timing and leakage sensitivity to systematic pattern dependent variation

NASA Astrophysics Data System (ADS)

Gupta, Puneet; Kahng, Andrew B.; Kim, Youngmin; Sylvester, Dennis

2006-03-01

Focus is one of the major sources of linewidth variation. CD variation caused by defocus is largely systematic after the layout is finished. In particular, dense lines "smile" through focus while isolated lines "frown" in typical Bossung plots. This well-defined systematic behavior of focus-dependent CD variation allows us to develop a self-compensating design methodology. In this work, we propose a novel design methodology that allows explicit compensation of focus-dependent CD variation, either within a cell (self-compensated cells) or across cells in a critical path (self-compensated design). By creating iso and dense variants for each library cell, we can achieve designs that are more robust to focus variation. Optimization with a mixture of iso and dense cell variants is possible both for area and leakage power, with the latter providing an interesting complement to existing leakage reduction techniques such as dual-Vth. We implement both heuristic and Mixed-Integer Linear Programming (MILP) solution methods to address this optimization, and experimentally compare their results. Our results indicate that designing with a self-compensated cell library incurs ~12% area penalty and ~6% leakage increase over original layouts while compensating for focus-dependent CD variation (i.e., the design meets timing constraints across a large range of focus variation). We observe ~27% area penalty and ~7% leakage increase at the worst-case defocus condition using only single-pitch cells. The area penalty of circuits after using either the heuristic or MILP optimization approach is reduced to ~3% while maintaining timing. We also apply our optimizations to leakage, which traditionally shows very large variability due to its exponential relationship with gate CD. We conclude that a mixed iso/dense library combined with a sensitivity-based optimization approach yields much better area/timing/leakage tradeoffs than using a self-compensated cell library alone. Self-compensated design shows an average of 25% leakage reduction at the worst defocus condition for the benchmark designs that we have studied.

Strength training in the elderly: effects on risk factors for age-related diseases.

PubMed

Hurley, B F; Roth, S M

2000-10-01

Strength training (ST) is considered a promising intervention for reversing the loss of muscle function and the deterioration of muscle structure that is associated with advanced age. This reversal is thought to result in improvements in functional abilities and health status in the elderly by increasing muscle mass, strength and power and by increasing bone mineral density (BMD). In the past couple of decades, many studies have examined the effects of ST on risk factors for age-related diseases or disabilities. Collectively, these studies indicate that ST in the elderly: (i) is an effective intervention against sarcopenia because it produces substantial increases in the strength, mass, power and quality of skeletal muscle; (ii) can increase endurance performance; (iii) normalises blood pressure in those with high normal values; (iv) reduces insulin resistance; (v) decreases both total and intra-abdominal fat; (vi) increases resting metabolic rate in older men; (vii) prevents the loss of BMD with age; (viii) reduces risk factors for falls; and (ix) may reduce pain and improve function in those with osteoarthritis in the knee region. However, contrary to popular belief, ST does not increase maximal oxygen uptake beyond normal variations, improve lipoprotein or lipid profiles, or improve flexibility in the elderly.

The relative contribution of patient, provider and organizational influences to the appropriate diagnosis and management of diabetes mellitus.

PubMed

Marceau, Lisa; McKinlay, John; Shackelton, Rebecca; Link, Carol

2011-12-01

To estimate the relative contribution of patient attributes, provider characteristics and organizational features of the doctors' workplace to the diagnosis and management of diabetes. In a factorial experimental design doctors (n = 192) viewed clinically authentic vignettes of 'patients' presenting with identical signs and symptoms. Doctor subjects were primary care doctors stratified according to gender and level of experience. During an in-person interview scheduled between real patients, doctors were asked how they would diagnosis and manage the vignette 'patients' in clinical practice. This study considered the relative contribution of patient, doctor and organizational factors. Taken together patient attributes explained only 4.4% of the variability in diabetes diagnosis. Doctor factors explained only 2.0%. The vast majority of the explained variance in diabetes diagnosis was due to organizational factors (14.3%). Relative contributions combined (patient, provider, organizational factors) explained only 20% of the total variance. Attempts to reduce health care variations usually focus on the education/activation of patients, or increased training of doctors. Our findings suggest that shifting quality improvement efforts to the area which contributes most to the creation and amplification of variations (organizational influences) may produce better results in terms of reduced variations in health care associated with diabetes. © 2010 Blackwell Publishing Ltd.

Susceptibility to keel bone fractures in laying hens and the role of genetic variation.

PubMed

Candelotto, Laura; Stratmann, Ariane; Gebhardt-Henrich, Sabine G; Rufener, Christina; van de Braak, Teun; Toscano, Michael J

2017-10-01

Keel bone fractures are a well-known welfare problem in modern commercial laying hen systems. The present study sought to identify genetic variation in relation to keel bone fracture susceptibility of 4 distinct crossbred and one pure line, and by extension, possible breeding traits. Susceptibility to fractures were assessed using an ex vivo impact testing protocol in combination with a study design that minimized environmental variation to focus on genetic differences. The 5 crossbred/pure lines differed in their susceptibility to keel bone fractures with the greatest likelihood of fracture in one of the 3 commercial lines and the lowest susceptibility to fractures in one of the experimental lines. Egg production at the hen-level did not differ between the crossbred/pure lines (P > 0.05), though an increased susceptibility to keel bone fractures was associated with thinner eggshells and reduced egg breaking strength, a pattern consistent among all tested crossbred/pure lines. Our findings suggest an association between egg quality and bone strength which appeared to be independent of crossbred/pure line. The findings indicate the benefit of the impact methodology to identify potential breeding characteristics to reduce incidence of keel fracture as well as the potential relationship with eggshell quality. © 2017 Poultry Science Association Inc.

Elevated Aerosol Layers and Their Radiative Impact over Kanpur During Monsoon Onset Period

NASA Technical Reports Server (NTRS)

Sarangi, Chandan; Tripathi, S. N.; Mishra, A. K.; Welton, E. J.

2016-01-01

Accurate information about aerosol vertical distribution is needed to reduce uncertainties in aerosol radiative forcing and its effect on atmospheric dynamics. The present study deals with synergistic analyses of aerosol vertical distribution and aerosol optical depth (AOD) with meteorological variables using multisatellite and ground-based remote sensors over Kanpur in central Indo-Gangetic Plain (IGP). Micro-Pulse Lidar Network-derived aerosol vertical extinction (sigma) profiles are analyzed to quantify the interannual and daytime variations during monsoon onset period (May-June) for 2009-2011. The mean aerosol profile is broadly categorized into two layers viz., a surface layer (SL) extending up to 1.5 km (where sigma decreased exponentially with height) and an elevated aerosol layer (EAL) extending between 1.5 and 5.5 km. The increase in total columnar aerosol loading is associated with relatively higher increase in contribution from EAL loading than that from SL. The mean contributions of EALs are about 60%, 51%, and 50% to total columnar AOD during 2009, 2010, and 2011, respectively. We observe distinct parabolic EALs during early morning and late evening but uniformly mixed EALs during midday. The interannual and daytime variations of EALs are mainly influenced by long-range transport and convective capacity of the local emissions, respectively. Radiative flux analysis shows that clear-sky incoming solar radiation at surface is reduced with increase in AOD, which indicates significant cooling at surface. Collocated analysis of atmospheric temperature and aerosol loading reveals that increase in AOD not only resulted in surface dimming but also reduced the temperature (approximately 2-3 C) of lower troposphere (below 3 km altitude). Radiative transfer simulations indicate that the reduction of incoming solar radiation at surface is mainly due to increased absorption by EALs (with increase in total AOD). The observed cooling in lower troposphere in high aerosol loading scenario could be understood as a dynamical feedback of EAL-induced stratification of lower troposphere. Further, the observed radiative effect of EALs increases the stability of the lower troposphere, which could modulate the large-scale atmospheric dynamics during monsoon onset period. These findings encourage follow-up studies on the implication of EALs to the Indian summer monsoon dynamics using numerical models.

A variational theory of Hall effect of Anderson lattice model: Application to colossal magnetoresistance manganites (Re1-x Ax MnO3)

NASA Astrophysics Data System (ADS)

Panwar, Sunil; Kumar, Vijay; Singh, Ishwar

2017-10-01

An anomalous Hall constant RH has been observed in various rare earth manganites doped with alkaline earths namely Re1-xAxMnO3 (where Re = La, Pr, Nd etc., and A = Ca, Sr, Ba etc.) which exhibit colossal magnetoresistance (CMR), metal- insulator transition and many other poorly understood phenomena. We show that this phenomenon of anomalous Hall constant can be understood using two band (ℓ-b) Anderson lattice model Hamiltonian alongwith (ℓ-b) hybridization recently studied by us for manganites in the strong electron-lattice Jahn-Teller (JT) coupling regime an approach similar to the two - fluid models. We use a variational method in this work to study the temperature variation of Hall constant RH (T) in these compounds. We have already used this variational method to study the zero field electrical resistivity ρ (T) and magnetic susceptibility of doped CMR manganites. In the present study, we find that the Hall constant RH (T) reduces with increasing magnetic field parameters h&m and the metal-insulator transition temperature (Tρ) shifts towards higher temperature region. We have also observed the role of the model parameters e.g. local Coulomb repulsion U, Hund's rule coupling JH between eg spins and t2g spins, ferromagnetic nearest neighbor exchange coupling JF between t2g core spins and hybridization Vk between ℓ-polarons and d-electrons on Hall constant RH (T) of these materials at different magnetic fields. Here we find that RH (T) for a particular value of h and m shows a rapid initial increase, followed by a sharp peak at low temperature say 50 K in our case and a slow decrease at high temperatures, resembling with the key feature of many CMR compounds like La0.8Ba0.2 MnO3.The magnitude of RH (T) reduces and the anomaly (sharp peak) in RH becomes broader and shifts towards higher temperature region on increasing Vk or JH or doping x and even vanishes on further increasing these parameters. Our results of anomalous Hall constant (RH) have same qualitative behavior as the zero-field electrical resistivity. Moreover Hall Constant (RH) shows positive values indicating that the carriers in these manganites are holes.

Genetic variations of VDR/NR1I1 encoding vitamin D receptor in a Japanese population.

PubMed

Ukaji, Maho; Saito, Yoshiro; Fukushima-Uesaka, Hiromi; Maekawa, Keiko; Katori, Noriko; Kaniwa, Nahoko; Yoshida, Teruhiko; Nokihara, Hiroshi; Sekine, Ikuo; Kunitoh, Hideo; Ohe, Yuichiro; Yamamoto, Noboru; Tamura, Tomohide; Saijo, Nagahiro; Sawada, Jun-ichi

2007-12-01

The vitamin D receptor (VDR) is a transcriptional factor responsive to 1alpha,25-dihydroxyvitamin D(3) and lithocholic acid, and induces expression of drug metabolizing enzymes CYP3A4, CYP2B6 and CYP2C9. In this study, the promoter regions, 14 exons (including 6 exon 1's) and their flanking introns of VDR were comprehensively screened for genetic variations in 107 Japanese subjects. Sixty-one genetic variations including 25 novel ones were found: 9 in the 5'-flanking region, 2 in the 5'-untranslated region (UTR), 7 in the coding exons (5 synonymous and 2 nonsynonymous variations), 12 in the 3'-UTR, 19 in the introns between the exon 1's, and 12 in introns 2 to 8. Of these, one novel nonsynonymous variation, 154A>G (Met52Val), was detected with an allele frequency of 0.005. The single nucleotide polymorphisms (SNPs) that increase VDR expression or activity, -29649G>A, 2T>C and 1592((*)308)C>A tagging linked variations in the 3'-UTR, were detected at 0.430, 0.636, and 0.318 allele frequencies, respectively. Another SNP, -26930A>G, with reduced VDR transcription was found at a 0.028 frequency. These findings would be useful for association studies on VDR variations in Japanese.

Neighbourhood green space, physical function and participation in physical activities among elderly men: the Caerphilly Prospective study

PubMed Central

2014-01-01

Background The built environment in which older people live plays an important role in promoting or inhibiting physical activity. Most work on this complex relationship between physical activity and the environment has excluded people with reduced physical function or ignored the difference between groups with different levels of physical function. This study aims to explore the role of neighbourhood green space in determining levels of participation in physical activity among elderly men with different levels of lower extremity physical function. Method Using data collected from the Caerphilly Prospective Study (CaPS) and green space data collected from high resolution Landmap true colour aerial photography, we first investigated the effect of the quantity of neighbourhood green space and the variation in neighbourhood vegetation on participation in physical activity for 1,010 men aged 66 and over in Caerphilly county borough, Wales, UK. Second, we explored whether neighbourhood green space affects groups with different levels of lower extremity physical function in different ways. Results Increasing percentage of green space within a 400 meters radius buffer around the home was significantly associated with more participation in physical activity after adjusting for lower extremity physical function, psychological distress, general health, car ownership, age group, marital status, social class, education level and other environmental factors (OR = 1.21, 95% CI 1.05, 1.41). A statistically significant interaction between the variation in neighbourhood vegetation and lower extremity physical function was observed (OR = 1.92, 95% CI 1.12, 3.28). Conclusion Elderly men living in neighbourhoods with more green space have higher levels of participation in regular physical activity. The association between variation in neighbourhood vegetation and regular physical activity varied according to lower extremity physical function. Subjects reporting poor lower extremity physical function living in neighbourhoods with more homogeneous vegetation (i.e. low variation) were more likely to participate in regular physical activity than those living in neighbourhoods with less homogeneous vegetation (i.e. high variation). Good lower extremity physical function reduced the adverse effect of high variation vegetation on participation in regular physical activity. This provides a basis for the future development of novel interventions that aim to increase levels of physical activity in later life, and has implications for planning policy to design, preserve, facilitate and encourage the use of green space near home. PMID:24646136

Neighbourhood green space, physical function and participation in physical activities among elderly men: the Caerphilly Prospective study.

PubMed

Gong, Yi; Gallacher, John; Palmer, Stephen; Fone, David

2014-03-19

The built environment in which older people live plays an important role in promoting or inhibiting physical activity. Most work on this complex relationship between physical activity and the environment has excluded people with reduced physical function or ignored the difference between groups with different levels of physical function. This study aims to explore the role of neighbourhood green space in determining levels of participation in physical activity among elderly men with different levels of lower extremity physical function. Using data collected from the Caerphilly Prospective Study (CaPS) and green space data collected from high resolution Landmap true colour aerial photography, we first investigated the effect of the quantity of neighbourhood green space and the variation in neighbourhood vegetation on participation in physical activity for 1,010 men aged 66 and over in Caerphilly county borough, Wales, UK. Second, we explored whether neighbourhood green space affects groups with different levels of lower extremity physical function in different ways. Increasing percentage of green space within a 400 meters radius buffer around the home was significantly associated with more participation in physical activity after adjusting for lower extremity physical function, psychological distress, general health, car ownership, age group, marital status, social class, education level and other environmental factors (OR = 1.21, 95% CI 1.05, 1.41). A statistically significant interaction between the variation in neighbourhood vegetation and lower extremity physical function was observed (OR = 1.92, 95% CI 1.12, 3.28). Elderly men living in neighbourhoods with more green space have higher levels of participation in regular physical activity. The association between variation in neighbourhood vegetation and regular physical activity varied according to lower extremity physical function. Subjects reporting poor lower extremity physical function living in neighbourhoods with more homogeneous vegetation (i.e. low variation) were more likely to participate in regular physical activity than those living in neighbourhoods with less homogeneous vegetation (i.e. high variation). Good lower extremity physical function reduced the adverse effect of high variation vegetation on participation in regular physical activity. This provides a basis for the future development of novel interventions that aim to increase levels of physical activity in later life, and has implications for planning policy to design, preserve, facilitate and encourage the use of green space near home.

Assessing vegetation response to climatic variations and human activities: spatiotemporal NDVI variations in the Hexi Corridor and surrounding areas from 2000 to 2010

NASA Astrophysics Data System (ADS)

Guan, Qingyu; Yang, Liqin; Guan, Wenqian; Wang, Feifei; Liu, Zeyu; Xu, Chuanqi

2018-03-01

Vegetation cover is a commonly used indicator for evaluating terrestrial environmental conditions, and for revealing environmental evolution and transitions. Spatiotemporal variations in the vegetation cover of the Hexi Corridor and surrounding areas from 2000 to 2010 were investigated using MODIS NDVI data, and the causes of vegetation cover changes were analyzed, considering both climatic variability and human activities. The vegetation cover of the study area increased during 2000-2010. The greenness of the vegetation showed a significant increase from the northwest to the southeast, which was similar to the spatial distribution of the annual precipitation. Variations in vegetation have a close relationship with those in precipitation within the Qilian Mountains region, but the NDVI is negatively correlated with precipitation in oasis areas. Increasing temperatures led to drought, inhibiting vegetation growth in summer; however, increasing temperatures may have also advanced and prolonged the growing periods in spring and autumn. The NDVI showed a slight degradation in March and July, primarily in the Qilian Mountains, and especially the Wushao Mountains. In March, due to low temperatures, the metabolism rate of vegetation was too slow to enable strong plant growth in high elevations of the Qilian Mountains. In July, increasing temperatures enhanced the intensity of transpiration and decreasing precipitation reduced the moisture available to plants, producing a slight degradation of vegetation in the Qilian Mountains. In May and August, the NDVI showed a significant improvement, primarily in the artificial oases and the Qilian Mountains. Abundant precipitation provided the necessary water for plant growth, and suitable temperatures increased the efficiency of photosynthesis, resulting in a significant improvement of vegetation in the Qilian Mountains. The improvement of production technologies, especially in irrigation, has been beneficial to the growth of vegetation in oasis areas. The implementation of large-scale vegetation management has led to several beneficial effects in the artificial oases and grasslands of the Qilian Mountains. [Figure not available: see fulltext.

Overview of vaccination policies for the elderly in Western European countries.

PubMed

Samson, Sandrine I; Mégard, Yves

2009-06-01

Age-related changes in the immune system are associated with increased susceptibility to infections, greater disease severity and poorer outcomes in the elderly compared with young adults. Both influenza and pneumonia are important causes of morbidity and mortality in the elderly, and herpes zoster also represents an important disease burden in this population. Vaccinations against influenza and Streptococcus pneumoniae (pneumococcus) have been shown to reduce the incidence of influenza and invasive pneumococcal disease, respectively, in the elderly. In addition, as is the case with diphtheria/tetanus and herpes zoster vaccines, they can help to reduce the associated burden of disease in vaccinated individuals. Despite the evidence of these benefits, there are considerable variations among the countries of Western Europe in their policies for vaccination in the elderly. Western European countries face the prospect of a population in which the proportion of elderly people is increasing, with a consequent increase in demand on the healthcare system. Acknowledgement of the benefits of vaccination in the elderly, together with comprehensive vaccination policies for this age group, could help to reduce some of these demands.

Status and Plans for the WCRP/GEWEX Global Precipitation Climatology Project (GPCP)

NASA Technical Reports Server (NTRS)

Adkerm Robert F.

2006-01-01

Status and plans for GPCP are presented along with scientific findings from the current data set. Global and large regional rainfall variations and possible long-term changes are examined using the 26-year (1979-2004) monthly dataset from the Global Precipitation Climatology Project (GPCP). One emphasis is to discriminate among the variations due to ENSO, volcanic events and possible long-term changes. Although the global change of precipitation in the data set is near zero, the data set does indicate an upward trend (0.13 mm/day/25yr) and a downward trend (-0.06 mm/day/25yr) over tropical oceans and lands (25S-25N), respectively. This corresponds to a 4% increase (ocean) and 2% decrease (land) during this time period. Simple techniques are derived to attempt to eliminate variations due to ENSO and major volcanic eruptions in the Tropics. Using only annual values two "volcano years" are determined by examining ocean-land coupled variations in precipitation related to ENSO and other phenomena. The outlier years coincide with Pinatubo and El Chicon eruptions. The ENSO signal is reduced by deriving mean ocean and land values for El Nino, La Nina and neutral conditions based on Nino 3.4 SST and normalizing the annual ocean and land precipitation to the neutral set of cases. The impact of the two major volcanic eruptions over the past 25 years is estimated to be about a 5% reduction in tropical rainfall. The modified data set (with ENSO and volcano effect at least partially removed) retains the same approximate linear change slopes over the data set period, but with reduced variance leading to significance tests with results in the 90-95% range. Intercomparisons between the GPCP, SSM/I (1988-2004), and TRMM (1998-2004) satellite rainfall products and alternate gauge analyses over land are made to attempt to increase or decrease confidence in the changes seen in the GPCP analysis.

Use of empirical and full Bayes before-after approaches to estimate the safety effects of roadside barriers with different crash conditions.

PubMed

Park, Juneyoung; Abdel-Aty, Mohamed; Lee, Jaeyoung

2016-09-01

Although many researchers have estimated the crash modification factors (CMFs) for specific treatments (or countermeasures), there is a lack of prior studies that have explored the variation of CMFs. Thus, the main objectives of this study are: (a) to estimate CMFs for the installation of different types of roadside barriers, and (b) to determine the changes of safety effects for different crash types, severities, and conditions. Two observational before-after analyses (i.e. empirical Bayes (EB) and full Bayes (FB) approaches) were utilized in this study to estimate CMFs. To consider the variation of safety effects based on different vehicle, driver, weather, and time of day information, the crashes were categorized based on vehicle size (passenger and heavy), driver age (young, middle, and old), weather condition (normal and rain), and time difference (day time and night time). The results show that the addition of roadside barriers is safety effective in reducing severe crashes for all types and run-off roadway (ROR) crashes. On the other hand, it was found that roadside barriers tend to increase all types of crashes for all severities. The results indicate that the treatment might increase the total number of crashes but it might be helpful in reducing injury and severe crashes. In this study, the variation of CMFs was determined for ROR crashes based on the different vehicle, driver, weather, and time information. Based on the findings from this study, the variation of CMFs can enhance the reliability of CMFs for different roadway conditions in decision making process. Also, it can be recommended to identify the safety effects of specific treatments for different crash types and severity levels with consideration of the different vehicle, driver, weather, and time of day information. Copyright © 2016 Elsevier Ltd and National Safety Council. All rights reserved.

Quantitative Genetic Architecture at Latitudinal Range Boundaries: Reduced Variation but Higher Trait Independence.

PubMed

Paccard, Antoine; Van Buskirk, Josh; Willi, Yvonne

2016-05-01

Species distribution limits are hypothesized to be caused by small population size and limited genetic variation in ecologically relevant traits, but earlier studies have not evaluated genetic variation in multivariate phenotypes. We asked whether populations at the latitudinal edges of the distribution have altered quantitative genetic architecture of ecologically relevant traits compared with midlatitude populations. We calculated measures of evolutionary potential in nine Arabidopsis lyrata populations spanning the latitudinal range of the species in eastern and midwestern North America. Environments at the latitudinal extremes have reduced water availability, and therefore plants were assessed under wet and dry treatments. We estimated genetic variance-covariance (G-) matrices for 10 traits related to size, development, and water balance. Populations at southern and northern distribution edges had reduced levels of genetic variation across traits, but their G-matrices were more spherical; G-matrix orientation was unrelated to latitude. As a consequence, the predicted short-term response to selection was at least as strong in edge populations as in central populations. These results are consistent with genetic drift eroding variation and reducing the effectiveness of correlational selection at distribution margins. We conclude that genetic variation of isolated traits poorly predicts the capacity to evolve in response to multivariate selection and that the response to selection may frequently be greater than expected at species distribution margins because of genetic drift.

The Long Run Impacts of Merit Aid: Evidence from California's Cal Grant. CEPA Working Paper No. 16-13

ERIC Educational Resources Information Center

Bettinger, Eric; Gurantz, Oded; Kawano, Laura; Sacerdote, Bruce

2016-01-01

We examine the impacts of being awarded a Cal Grant, among the most generous state merit aid programs. We exploit variation in eligibility rules using GPA and family income cutoffs that are ex ante unknown to applicants. Cal Grant eligibility increases degree completion by 2 to 5 percentage points in our reduced form estimates. Cal Grant also…

A correlation between structural distortion and variation of TC in Ba1-x/2LaxBi4-x/2Ti4O15

NASA Astrophysics Data System (ADS)

Asha, M. Arul; Gajendra Babu, M. Veera; Abdul Kader, S. M.; Sundarakannan, B.; Srihari, V.; Sridharan, V.

2012-06-01

Ba and Bi ions were simultaneously substituted by La ion up to 0.3 mole fraction and studied by powder XRD and temperature dependent dielectric measurements. Perovskite slab thickness reduces due to octahedral tilting and the cell volume decreases. Low mole fraction of simultaneous substitution of La is preferred as it increases physical properties.

Hospital variation and the impact of postoperative complications on the use of perioperative chemo(radio)therapy in resectable gastric cancer. Results from the Dutch Upper GI Cancer Audit.

PubMed

Schouwenburg, M G; Busweiler, L A D; Beck, N; Henneman, D; Amodio, S; van Berge Henegouwen, M I; Cats, A; van Hillegersberg, R; van Sandick, J W; Wijnhoven, B P L; Wouters, M W J; Nieuwenhuijzen, G A P

2018-04-01

Dutch national guidelines on the diagnosis and treatment of gastric cancer recommend the use of perioperative chemotherapy in patients with resectable gastric cancer. However, adjuvant chemotherapy is often not administered. The aim of this study was to evaluate hospital variation on the probability to receive adjuvant chemotherapy and to identify associated factors with special attention to postoperative complications. All patients who received neoadjuvant chemotherapy and underwent an elective surgical resection for stage IB-IVa (M0) gastric adenocarcinoma between 2011 and 2015 were identified from a national database (Dutch Upper GI Cancer Audit). A multivariable linear mixed model was used to evaluate case-mix adjusted hospital variation and to identify factors associated with adjuvant therapy. Of all surgically treated gastric cancer patients who received neoadjuvant chemotherapy (n = 882), 68% received adjuvant chemo(radio)therapy. After adjusting for case-mix and random variation, a large hospital variation in the administration rates for adjuvant was observed (OR range 0.31-7.1). In multivariable analysis, weight loss, a poor health status and failure of neoadjuvant chemotherapy completion were strongly associated with an increased likelihood of adjuvant therapy omission. Patients with severe postoperative complications had a threefold increased likelihood of adjuvant therapy omission (OR 3.07 95% CI 2.04-4.65). Despite national guidelines, considerable hospital variation was observed in the probability of receiving adjuvant chemo(radio)therapy. Postoperative complications were strongly associated with adjuvant chemo(radio)therapy omission, underlining the need to further reduce perioperative morbidity in gastric cancer surgery. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Inbreeding and disease resistance in a social insect: effects of heterozygosity on immunocompetence in the termite Zootermopsis angusticollis

PubMed Central

Calleri, Daniel V; McGrail Reid, Ellen; Rosengaus, Rebeca B; Vargo, Edward L; Traniello, James F.A

2006-01-01

Recent research has shown that low genetic variation in individuals can increase susceptibility to infection and group living may exacerbate pathogen transmission. In the eusocial diploid termites, cycles of outbreeding and inbreeding characterizing basal species can reduce genetic variation within nestmates during the life of a colony, but the relationship of genetic heterogeneity to disease resistance is poorly understood. Here we show that, one generation of inbreeding differentially affects the survivorship of isolated and grouped termites (Zootermopsis angusticollis) depending on the nature of immune challenge and treatment. Inbred and outbred isolated and grouped termites inoculated with a bacterial pathogen, exposed to a low dose of fungal pathogen or challenged with an implanted nylon monofilament had similar levels of immune defence. However, inbred grouped termites exposed to a relatively high concentration of fungal conidia had significantly greater mortality than outbred grouped termites. Inbred termites also had significantly higher cuticular microbial loads, presumably due to less effective grooming by nestmates. Genetic analyses showed that inbreeding significantly reduced heterozygosity and allelic diversity. Decreased heterozygosity thus appeared to increase disease susceptibility by affecting social behaviour or some other group-level process influencing infection control rather than affecting individual immune physiology. PMID:17002949

Regulation of Carotid Body Oxygen Sensing by Hypoxia-Inducible Factors

PubMed Central

Prabhakar, Nanduri R.; Semenza, Gregg L.

2015-01-01

Oxygen (O2) sensing by the carotid body and its chemosensory reflex is critical for homeostatic regulation of breathing and blood pressure. Carotid body responses to hypoxia are not uniform but instead exhibit remarkable inter-individual variations. The molecular mechanisms underlying variations in carotid body O2 sensing are not known. Hypoxia-inducible factor-1 (HIF-1) and HIF-2 mediate transcriptional responses to hypoxia. This article reviews the emerging evidence that proper expression of the HIF-α isoforms is a key molecular determinant for carotid body O2 sensing. HIF-1α deficiency leads to a blunted carotid body hypoxic response, which is due to increased abundance of HIF-2α, elevated anti-oxidant enzyme activity, and a reduced intracellular redox state. Conversely, HIF-2α deficiency results in augmented carotid body sensitivity to hypoxia, which is due to increased abundance of HIF-1α, elevated pro-oxidant enzyme activity, and an oxidized intracellular redox state. Double heterozygous mice with equally reduced HIF-1α and HIF-2α showed no abnormality in redox state or carotid body O2 sensing. Thus, mutual antagonism between HIF-α isoforms determines the redox state and thereby establishes the set point for hypoxic sensing by the carotid body. PMID:26265380

Size-induced changes of structural and ferromagnetic properties in La1-xSrxMnO3 nanoparticles

NASA Astrophysics Data System (ADS)

Hintze, Cornelia E.; Fuchs, Dirk; Merz, Michael; Amari, Houari; Kübel, Christian; Huang, Meng-Jie; Powell, Annie; v. Löhneysen, Hilbert

2017-06-01

La1-xSrxMnO3 nanocrystals were grown using a microemulsion approach with different water-to-surfactant ratios Rw resulting in diameters between 20 and 40 nm. The variation of Rw entails a variation in the Sr concentrations between x = 0.35 and 0.50. This technique allows the controlled growth of structurally well-defined nanoparticles using the same calcination conditions. With decreasing particle size, the unit-cell volume increases together with the Mn-O bond length, while the Mn-O-Mn bond angle was found to decrease. The size-dependent change of structural properties is possibly related to surface effects or disorder. With the decrease in particle size, the ferromagnetic ordering temperature TC decreases significantly by up to 20%. The reduction of TC can be well understood with respect to the structural changes: the increase of Mn-O bond length and the decrease of Mn-O-Mn bond angle weaken the double-exchange coupling and hence reduce T C . In addition the intrinsic finite-size effect reduces T C . The observed size-induced change of magnetic properties may allow for a controlled manipulation of magnetism in La1-xSrxMnO3 nanoparticles by varying the particle size.

Genetics Show Current Decline and Pleistocene Expansion in Northern Spotted Owls

USGS Publications Warehouse

Funk, W. Chris; Forsman, Eric D.; Mullins, Thomas D.; Haig, Susan M.

2008-01-01

The northern spotted owl (Strix occidentalis caurina) is one of the most controversial threatened subspecies ever listed under the U.S. Endangered Species Act. Because of concern for persistence of the subspecies, logging on Federal lands in the U.S. Pacific Northwest was dramatically reduced under the Northwest Forest Plan in 1994. Despite protection of its remaining forest habitat, recent field studies show continued demographic declines of northern spotted owls. One potential threat to northern spotted owls that has not yet been shown is loss of genetic variation from population bottlenecks that can increase inbreeding depression and decrease adaptive potential. Here, we show recent genetic bottlenecks in northern spotted owls using a large genetic dataset (352 individuals from across the subspecies' range and 11 microsatellite loci). The signature of bottlenecks was strongest in Washington State, in agreement with field data. Interestingly, we also found a genetic signature of Pleistocene expansion in the same study areas where recent bottlenecks were shown. Our results provide independent evidence that northern spotted owls have recently declined, and suggest that loss of genetic variation is an emerging threat to the subspecies' persistence. Reduced effective population size (Ne), shown here in addition to field evidence for demographic decline, highlights the increasing vulnerability of this bird to extinction.

Improvement of Diurnal Blood Pressure Variation by Azilsartan.

PubMed

Okamura, Keisuke; Shirai, Kazuyuki; Okuda, Tetsu; Urata, Hidenori

2018-01-01

Azilsartan is an angiotensin II receptor blocker with a potent antihypertensive effect. In a multicenter, prospective, open-label study, 265 patients with poor blood pressure control despite treatment with other angiotensin II receptor blockers were switched to 20 mg/day of azilsartan (patients on standard dosages) or 40 mg/day of azilsartan (patients on high dosages). Blood pressure was 149/83 mm Hg before switching and was significantly reduced from 1 month after switching until final assessment (132/76 mm Hg, P < 0.001). The pulse rate was 72/min before switching and increased significantly from 3 months after switching until final assessment (74/min, P < 0.005). A significant decrease of home morning systolic and diastolic pressure was observed from 1 and 3 months, respectively. Home morning blood pressure was 143/82 mm Hg before switching and 130/76 mm Hg at final assessment (P < 0.01). The morning-evening difference of systolic blood pressure decreased from 14.6 to 6.6 mm Hg after switching (P = 0.09). The estimated glomerular filtration rate was significantly decreased at 3, 6, and 12 months after switching, and serum uric acid was significantly increased at 12 months. No serious adverse events occurred. Azilsartan significantly reduced the blood pressure and decreased diurnal variation in patients responding poorly to other angiotensin II receptor blockers.

Environmental Variation Generates Environmental Opportunist Pathogen Outbreaks.

PubMed

Anttila, Jani; Kaitala, Veijo; Laakso, Jouni; Ruokolainen, Lasse

2015-01-01

Many socio-economically important pathogens persist and grow in the outside host environment and opportunistically invade host individuals. The environmental growth and opportunistic nature of these pathogens has received only little attention in epidemiology. Environmental reservoirs are, however, an important source of novel diseases. Thus, attempts to control these diseases require different approaches than in traditional epidemiology focusing on obligatory parasites. Conditions in the outside-host environment are prone to fluctuate over time. This variation is a potentially important driver of epidemiological dynamics and affect the evolution of novel diseases. Using a modelling approach combining the traditional SIRS models to environmental opportunist pathogens and environmental variability, we show that epidemiological dynamics of opportunist diseases are profoundly driven by the quality of environmental variability, such as the long-term predictability and magnitude of fluctuations. When comparing periodic and stochastic environmental factors, for a given variance, stochastic variation is more likely to cause outbreaks than periodic variation. This is due to the extreme values being further away from the mean. Moreover, the effects of variability depend on the underlying biology of the epidemiological system, and which part of the system is being affected. Variation in host susceptibility leads to more severe pathogen outbreaks than variation in pathogen growth rate in the environment. Positive correlation in variation on both targets can cancel the effect of variation altogether. Moreover, the severity of outbreaks is significantly reduced by increase in the duration of immunity. Uncovering these issues helps in understanding and controlling diseases caused by environmental pathogens.

Three-dimensional hydrodynamic simulations of OMEGA implosions

NASA Astrophysics Data System (ADS)

Igumenshchev, I. V.; Michel, D. T.; Shah, R. C.; Campbell, E. M.; Epstein, R.; Forrest, C. J.; Glebov, V. Yu.; Goncharov, V. N.; Knauer, J. P.; Marshall, F. J.; McCrory, R. L.; Regan, S. P.; Sangster, T. C.; Stoeckl, C.; Schmitt, A. J.; Obenschain, S.

2017-05-01

The effects of large-scale (with Legendre modes ≲ 10) asymmetries in OMEGA direct-drive implosions caused by laser illumination nonuniformities (beam-power imbalance and beam mispointing and mistiming), target offset, and variation in target-layer thickness were investigated using the low-noise, three-dimensional Eulerian hydrodynamic code ASTER. Simulations indicate that these asymmetries can significantly degrade the implosion performance. The most important sources of the asymmetries are the target offsets ( ˜10 to 20 μm), beam-power imbalance ( σrms˜10 %), and variations ( ˜5 %) in target-layer thickness. Large-scale asymmetries distort implosion cores, resulting in a reduced hot-spot confinement and an increased residual kinetic energy of implosion targets. The ion temperature inferred from the width of simulated neutron spectra is influenced by bulk fuel motion in the distorted hot spot and can result in up to an ˜1 -keV increase in apparent temperature. Similar temperature variations along different lines of sight are observed. Demonstrating hydrodynamic equivalence to ignition designs on OMEGA requires a reduction in large-scale target and laser-imposed nonuniformities, minimizing target offset, and employing highly efficient mid-adiabat (α = 4) implosion designs, which mitigate cross-beam energy transfer and suppress short-wavelength Rayleigh-Taylor growth.

Three-dimensional hydrodynamic simulations of OMEGA implosions

DOE PAGES

Igumenshchev, I. V.; Michel, D. T.; Shah, R. C.; ...

2017-03-30

Here, the effects of large-scale (with Legendre modes ≲10) asymmetries in OMEGA direct-drive implosions caused by laser illumination nonuniformities (beam-power imbalance and beam mispointing and mistiming), target offset, and variation in target-layer thickness were investigated using the low-noise, three-dimensional Eulerian hydrodynamic code ASTER. Simulations indicate that these asymmetries can significantly degrade the implosion performance. The most important sources of the asymmetries are the target offsets (~10 to 20 μm), beam-power imbalance (σ rms ~ 10%), and variations (~5%) in target-layer thickness. Large-scale asymmetries distort implosion cores, resulting in a reduced hot-spot confinement and an increased residual kinetic energy of implosionmore » targets. The ion temperature inferred from the width of simulated neutron spectra is influenced by bulk fuel motion in the distorted hot spot and can result in up to an ~1 -keV increase in apparent temperature. Similar temperature variations along different lines of sight are observed. Demonstrating hydrodynamic equivalence to ignition designs on OMEGA requires a reduction in large-scale target and laser-imposed nonuniformities, minimizing target offset, and employing highly efficient mid-adiabat (α = 4) implosion designs, which mitigate cross-beam energy transfer and suppress short-wavelength Rayleigh–Taylor growth.« less

A Strip Cell in Pyroelectric Devices

PubMed Central

Siao, An-Shen; Chao, Ching-Kong; Hsiao, Chun-Ching

2016-01-01

The pyroelectric effect affords the opportunity to convert temporal temperature fluctuations into usable electrical energy in order to develop abundantly available waste heat. A strip pyroelectric cell, used to enhance temperature variation rates by lateral temperature gradients and to reduce cell capacitance to further promote the induced voltage, is described as a means of improving pyroelectric energy transformation. A precision dicing saw was successfully applied in fabricating the pyroelectric cell with a strip form. The strip pyroelectric cell with a high-narrow cross section is able to greatly absorb thermal energy via the side walls of the strips, thereby inducing lateral temperature gradients and increasing temperature variation rates in a thicker pyroelectric cell. Both simulation and experimentation show that the strip pyroelectric cell improves the electrical outputs of pyroelectric cells and enhances the efficiency of pyroelectric harvesters. The strip-type pyroelectric cell has a larger temperature variation when compared to the trenched electrode and the original type, by about 1.9 and 2.4 times, respectively. The measured electrical output of the strip type demonstrates a conspicuous increase in stored energy as compared to the trenched electrode and the original type, by of about 15.6 and 19.8 times, respectively. PMID:26999134

Three-dimensional hydrodynamic simulations of OMEGA implosions

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

Igumenshchev, I. V.; Michel, D. T.; Shah, R. C.

Here, the effects of large-scale (with Legendre modes ≲10) asymmetries in OMEGA direct-drive implosions caused by laser illumination nonuniformities (beam-power imbalance and beam mispointing and mistiming), target offset, and variation in target-layer thickness were investigated using the low-noise, three-dimensional Eulerian hydrodynamic code ASTER. Simulations indicate that these asymmetries can significantly degrade the implosion performance. The most important sources of the asymmetries are the target offsets (~10 to 20 μm), beam-power imbalance (σ rms ~ 10%), and variations (~5%) in target-layer thickness. Large-scale asymmetries distort implosion cores, resulting in a reduced hot-spot confinement and an increased residual kinetic energy of implosionmore » targets. The ion temperature inferred from the width of simulated neutron spectra is influenced by bulk fuel motion in the distorted hot spot and can result in up to an ~1 -keV increase in apparent temperature. Similar temperature variations along different lines of sight are observed. Demonstrating hydrodynamic equivalence to ignition designs on OMEGA requires a reduction in large-scale target and laser-imposed nonuniformities, minimizing target offset, and employing highly efficient mid-adiabat (α = 4) implosion designs, which mitigate cross-beam energy transfer and suppress short-wavelength Rayleigh–Taylor growth.« less

Spatiotemporal variations in vegetation cover on the Loess Plateau, China, between 1982 and 2013: possible causes and potential impacts.

PubMed

Kong, Dongxian; Miao, Chiyuan; Borthwick, Alistair G L; Lei, Xiaohui; Li, Hu

2018-05-01

Vegetation is a key component of the ecosystem and plays an important role in water retention and resistance to soil erosion. In this study, we used a multiyear normalized difference vegetation index (NDVI) dataset (1982-2013) and corresponding datasets for observed climatic variables to analyze changes in the NDVI at both temporal and spatial scales. The relationships between NDVI, climate change, and human activities were also investigated. The annual average NDVI showed an upward trend over the 32-year study period, especially in the center of the Loess Plateau. NDVI variations lagged behind monthly temperature changes by approximately 1 month. The contribution of human activities to variations in NDVI has become increasingly significant in recent years, with human activities responsible for 30.4% of the change in NDVI during the period 2001-2013. The increased vegetation coverage has reduced soil erosion on the Loess Plateau in recent years. It is suggested that natural restoration of vegetation is the most effective measure for control of erosion; engineering measures that promote this should feature in the future governance of the Loess Plateau.

Soil biota and agriculture production in conventional and organic farming

NASA Astrophysics Data System (ADS)

Schrama, Maarten; de Haan, Joj; Carvalho, Sabrina; Kroonen, Mark; Verstegen, Harry; Van der Putten, Wim

2015-04-01

Sustainable food production for a growing world population requires a healthy soil that can buffer environmental extremes and minimize its losses. There are currently two views on how to achieve this: by intensifying conventional agriculture or by developing organically based agriculture. It has been established that yields of conventional agriculture can be 20% higher than of organic agriculture. However, high yields of intensified conventional agriculture trade off with loss of soil biodiversity, leaching of nutrients, and other unwanted ecosystem dis-services. One of the key explanations for the loss of nutrients and GHG from intensive agriculture is that it results in high dynamics of nutrient losses, and policy has aimed at reducing temporal variation. However, little is known about how different agricultural practices affect spatial variation, and it is unknown how soil fauna acts this. In this study we compare the spatial and temporal variation of physical, chemical and biological parameters in a long term (13-year) field experiment with two conventional farming systems (low and medium organic matter input) and one organic farming system (high organic matter input) and we evaluate the impact on ecosystem services that these farming systems provide. Soil chemical (N availability, N mineralization, pH) and soil biological parameters (nematode abundance, bacterial and fungal biomass) show considerably higher spatial variation under conventional farming than under organic farming. Higher variation in soil chemical and biological parameters coincides with the presence of 'leaky' spots (high nitrate leaching) in conventional farming systems, which shift unpredictably over the course of one season. Although variation in soil physical factors (soil organic matter, soil aggregation, soil moisture) was similar between treatments, but averages were higher under organic farming, indicating more buffered conditions for nutrient cycling. All these changes coincide with pronounced shifts in soil fauna composition (nematodes, earthworms) and an increase in earthworm activity. Hence, more buffered conditions and shifts in soil fauna composition under organic farming may underlie the observed reduction in spatial variation of soil chemical and biological parameters, which in turn correlates positively with a long-term increase in yield. Our study highlights the need for both policymakers and farmers alike to support spatial stability-increasing farming.

The methane distribution on Titan: high resolution spectroscopy in the near-IR with Keck NIRSPEC/AO

NASA Astrophysics Data System (ADS)

Adamkovics, Mate; Mitchell, Jonathan L.

2014-11-01

The distribution of methane on Titan is a diagnostic of regional scale meteorology and large scale atmospheric circulation. The observed formation of clouds and the transport of heat through the atmosphere both depend on spatial and temporal variations in methane humidity. We have performed observations to measure the the distribution on methane Titan using high spectral resolution near-IR (H-band) observations made with NIRSPEC, with adaptive optics, at Keck Observatory in July 2014. This work builds on previous attempts at this measurement with improvement in the observing protocol and data reduction, together with increased integration times. Radiative transfer models using line-by-line calculation of methane opacities from the HITRAN2012 database are used to retrieve methane abundances. We will describe analysis of the reduced observations, which show latitudinal spatial variation in the region the spectrum that is thought to be sensitive to methane abundance. Quantifying the methane abundance variation requires models that include the spatial variation in surface albedo and meridional haze gradient; we will describe (currently preliminary) analysis of the the methane distribution and uncertainties in the retrieval.

Cell-to-cell variation and specialization in sugar metabolism in clonal bacterial populations

PubMed Central

Schreiber, Frank; Dal Co, Alma; Kiviet, Daniel J.; Littmann, Sten

2017-01-01

While we have good understanding of bacterial metabolism at the population level, we know little about the metabolic behavior of individual cells: do single cells in clonal populations sometimes specialize on different metabolic pathways? Such metabolic specialization could be driven by stochastic gene expression and could provide individual cells with growth benefits of specialization. We measured the degree of phenotypic specialization in two parallel metabolic pathways, the assimilation of glucose and arabinose. We grew Escherichia coli in chemostats, and used isotope-labeled sugars in combination with nanometer-scale secondary ion mass spectrometry and mathematical modeling to quantify sugar assimilation at the single-cell level. We found large variation in metabolic activities between single cells, both in absolute assimilation and in the degree to which individual cells specialize in the assimilation of different sugars. Analysis of transcriptional reporters indicated that this variation was at least partially based on cell-to-cell variation in gene expression. Metabolic differences between cells in clonal populations could potentially reduce metabolic incompatibilities between different pathways, and increase the rate at which parallel reactions can be performed. PMID:29253903

The importance of work organization on workload and musculoskeletal health--Grocery store work as a model.

PubMed

Balogh, I; Ohlsson, K; Nordander, C; Björk, J; Hansson, G-Å

2016-03-01

We have evaluated the consequences of work organization on musculoskeletal health. Using a postal questionnaire, answered by 1600 female grocery store workers, their main work tasks were identified and four work groups were defined (cashier, picking, and delicatessen work, and a mixed group, who performed a mix of these tasks). The crude odds ratios (ORs) for neck/shoulder complaints were 1.5 (95% CI 1.0-2.2), 1.1 (0.7-1.5) and 1.6 (1.1-2.3), respectively, compared to mixed work. Adjusting for individual and psychosocial factors had no effect on these ORs. For elbows/hands, no significant differences were found. Technical measurements of the workload showed large differences between the work groups. Picking work was the most strenuous, while cashier work showed low loads. Quantitative measures of variation revealed for mixed work high between minutes variation and the highest between/within minutes variation. Combining work tasks with different physical exposure levels increases the variation and may reduce the risk of musculoskeletal complaints. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

The spatial and metabolic basis of colony size variation.

PubMed

Chacón, Jeremy M; Möbius, Wolfram; Harcombe, William R

2018-03-01

Spatial structure impacts microbial growth and interactions, with ecological and evolutionary consequences. It is therefore important to quantitatively understand how spatial proximity affects interactions in different environments. We tested how proximity influences colony size when either Escherichia coli or Salmonella enterica are grown on various carbon sources. The importance of colony location changed with species and carbon source. Spatially explicit, genome-scale metabolic modeling recapitulated observed colony size variation. Competitors that determine territory size, according to Voronoi diagrams, were the most important drivers of variation in colony size. However, the relative importance of different competitors changed through time. Further, the effect of location increased when colonies took up resources quickly relative to the diffusion of limiting resources. These analyses made it apparent that the importance of location was smaller than expected for experiments with S. enterica growing on glucose. The accumulation of toxic byproducts appeared to limit the growth of large colonies and reduced variation in colony size. Our work provides an experimentally and theoretically grounded understanding of how location interacts with metabolism and diffusion to influence microbial interactions.

Signal polymorphism under a constant environment: the odd cross in a web decorating spider

NASA Astrophysics Data System (ADS)

Walter, André; Elgar, Mark A.

2016-12-01

The quality of many animal signals varies, perhaps through their use in different contexts or by representing an adaptive response to reduce the risk of exploitation. Spiders of the orb weaver genus Argiope add linear, cruciate or circular silk structures to their orb webs, creating inter- and intra-specific polymorphic visual signals. Different decoration patterns are frequently attributed to different signal effects, but this view is contradicted by commonly observed intraspecific variation in decorating behaviour. Adults of Argiope mascordi are bimodal web decorators, building two distinct patterns, circular and cruciate silk structures. We investigated the variation of patterns under controlled, invariant laboratory conditions. Circular decorations were most frequent, but individuals often switch to the other pattern. This variation neither increased nor decreased over time, suggesting that pattern variability is primarily intrinsic rather than an exclusive response to environmental changes. Accordingly, we discuss the evolutionary implications in the light of the conservation of a single signal function through maintaining the variation of its quality and the alternative view that silk decorations may not represent adaptive signals at all.

Improving electrofishing catch consistency by standardizing power

USGS Publications Warehouse

Burkhardt, Randy W.; Gutreuter, Steve

1995-01-01

The electrical output of electrofishing equipment is commonly standardized by using either constant voltage or constant amperage, However, simplified circuit and wave theories of electricity suggest that standardization of power (wattage) available for transfer from water to fish may be critical for effective standardization of electrofishing. Electrofishing with standardized power ensures that constant power is transferable to fish regardless of water conditions. The in situ performance of standardized power output is poorly known. We used data collected by the interagency Long Term Resource Monitoring Program (LTRMP) in the upper Mississippi River system to assess the effectiveness of standardizing power output. The data consisted of 278 electrofishing collections, comprising 9,282 fishes in eight species groups, obtained during 1990 from main channel border, backwater, and tailwater aquatic areas in four reaches of the upper Mississippi River and one reach of the Illinois River. Variation in power output explained an average of 14.9% of catch variance for night electrofishing and 12.1 % for day electrofishing. Three patterns in catch per unit effort were observed for different species: increasing catch with increasing power, decreasing catch with increasing power, and no power-related pattern. Therefore, in addition to reducing catch variation, controlling power output may provide some capability to select particular species. The LTRMP adopted standardized power output beginning in 1991; standardized power output is adjusted for variation in water conductivity and water temperature by reference to a simple chart. Our data suggest that by standardizing electrofishing power output, the LTRMP has eliminated substantial amounts of catch variation at virtually no additional cost.

Implications of temporal variation in maternal care for the prediction of neurobiological and behavioral outcomes in offspring

PubMed Central

Peña, Catherine Jensen; Champagne, Frances A.

2014-01-01

Previous studies in Long-Evans rats demonstrated a significant relationship between variation in pup licking/grooming and arched-back nursing (LG-ABN) and offspring development. However, maternal care is dynamic and exhibits significant temporal variation. In the current study, we assessed temporal variation in LG and ABN in lactating rats across the circadian cycle and determined the impact of these behaviors for the prediction of offspring hypothalamic gene expression, anxiety-like behavior, and responsiveness to high fat diet (HFD). We find that distinguishing between dams that engage in stable individual differences in maternal behavior (Low, Mid, High) requires assessment across the light-dark phases of the light cycle and across multiple postpartum days. Amongst juvenile female offspring, we find a positive correlation between maternal LG and mRNA levels of estrogen receptor alpha and beta and the oxytocin receptor (when LG is assessed across the light-dark cycle or in the dark phase). In young adults, we find sex-specific effects, with female High LG offspring exhibiting increased exploration of a novel environment and increased latency to approach HFD and male High LG offspring displaying increased activity in a novel environment and reduced HFD consumption. Importantly, these effects on behavior were primarily evident when LG was assessed across the light-dark cycle and ABN was not associated with these measures. Overall, our findings illustrate the dissociation between the effects of LG and ABN on offspring development and provide critical insights into the temporal characteristics of maternal behavior that have methodological implications for the study of maternal effects. PMID:23398440

Sigh rate and respiratory variability during mental load and sustained attention.

PubMed

Vlemincx, Elke; Taelman, Joachim; De Peuter, Steven; Van Diest, Ilse; Van den Bergh, Omer

2011-01-01

Spontaneous breathing consists of substantial correlated variability: Parameters characterizing a breath are correlated with parameters characterizing previous and future breaths. On the basis of dynamic system theory, negative emotion states are predicted to reduce correlated variability whereas sustained attention is expected to reduce total respiratory variability. Both are predicted to evoke sighing. To test this, respiratory variability and sighing were assessed during a baseline, stressful mental arithmetic task, nonstressful sustained attention task, and recovery in between tasks. For respiration rate (excluding sighs), reduced total variability was found during the attention task, whereas correlated variation was reduced during mental load. Sigh rate increased during mental load and during recovery from the attention task. It is concluded that mental load and task-related attention show specific patterns in respiratory variability and sigh rate. Copyright © 2010 Society for Psychophysiological Research.

The effect of price and production risks on optimal farm plans in Swiss dairy production considering 2 different milk quota systems.

PubMed

Briner, S; Finger, R

2013-04-01

The amount of milk produced on Swiss dairy farms is restricted by contracts between the farmers and their marketing agent. In the past, these contracts have been calculated on a yearly base. Due to a switch in agricultural policy, these yearly contracts are currently more and more replaced by contracts calculated on a monthly base. These new contracts are assumed to restrict the flexibility of farmers to react on changes in milk price as well as on changes in fodder availability. Thus, the contract design is expected to influence farmers' ability to cope with risks and, thus, to influence the farm's gross margin variability. Applying a bioeconomic whole-farm model, the effects of price and weather risk as well as different risk-management strategies on the gross margin and the variability of the gross margin in Swiss dairy production are assessed under the 2 contract designs. We consider both risk-neutral and risk-averse behavior of farmers in our study. Results show that gross margin is slightly higher under the yearly than under the monthly contract. Variability of gross margin is also higher under the yearly than under the monthly contract. If the farmer is assumed to be risk averse, under both contracts he can reduce the coefficient of variation of the gross margin by almost 20% at opportunity costs below 1% of the gross margin. To reduce variability of gross margin under both contracts the size of the feedstock needs to be increased. This increase, however, must be considerably higher under the monthly contract than under the yearly contract. An additional risk-management strategy under a monthly contract is an increase in the area used as intensive pasture to ensure fodder availability in years with unfavorable weather. Under the yearly contract, an increase in the area used as extensive pasture is shown to be more favorable because it increases the amount of direct payments the farmer will receive. Additional restrictions in farm management due to a monthly milk contract do not lead to a higher variation in gross margin. However, if a farmer agrees to a monthly contract, he needs to adapt his risk-management strategies. Furthermore, our results show that farmers have to be aware that they will need additional barn capacities to reduce variation in gross margin under a monthly milk contract. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Simulation and Experimental Study on Effect of Phase Change Material Thickness to Reduce Temperature of Photovoltaic Panel

NASA Astrophysics Data System (ADS)

Indartono, Y. S.; Prakoso, S. D.; Suwono, A.; Zaini, I. N.; Fernaldi, B.

2015-09-01

Solar energy is promising renewable energy which can be applied in Indonesia. Average solar radiation in the country is 4.8 kWh/day/m2. Weakness of silicon-based photovoltaic (PV) is efficiency reduction caused by temperature increase. Many attempts have been done to reduce PV temperature. In previous study, palm oil, which is widely available in Indonesia, is suitable to be used as phase change material (PCM) to reduce PV temperature. In this study, thickness of aluminium rectangular-tube containing phase change material oil is varied. The tube is placed at back part of PV. Numerical and experimental study was done to evaluate the effect of tube thickness to the temperature reduction of the PV. Variation of tube thickness used in the experiment is 50.8mm, 76.2 mm, 101.6 mm. Both studies show that increase of PCM thickness reduces PV temperature. Higher PCM thickness cause large reduction on PV temperature. Simulation result shows there is an optimum thickness of the PCM which is applied to the PV.

Coal/rock interface detection by sensitized pick, part A

NASA Technical Reports Server (NTRS)

Wu, P. T. K.; Erkes, J. W.

1981-01-01

In order to increase the operating margins of the detector for safe, reliable operation under difficult in-mine conditions the transmitted signal strength was increased to provide additional signal margin for in-mine conditions and the transmitter section was redesigned to reduce frequency pulling of the transmitter frequency with variations in antenna load. The linearity of the pick load SCO signal with true pick load was increased, and hysteresis effects were minimized. The sensitized pick hardware was ruggedized for rough inmine use. The sensitized pick and telemetry system provided excellent, high quality signals proportional to cutting load under all conditions experienced during testing.

Spatiotemporal variation of crown-scale stomatal conductance in an arid Vitis vinifera L. cv. Merlot vineyard: direct effects of hydraulic properties and indirect effects of canopy leaf area.

PubMed

Zhang, Yanqun; Oren, Ram; Kang, Shaozhong

2012-03-01

Vineyards were planted in the arid region of northwest China to meet the local economic strategy while reducing agricultural water use. Sap flow, environmental variables, a plant characteristic (sapwood-to-leaf area ratio, A(s)/A(l)) and a canopy characteristic (leaf area index, L) were measured in a vineyard in the region during the growing season of 2009, and hourly canopy stomatal conductance (G(si)) was estimated for individual vines to quantify the relationships between G(si) and these variables. After accounting for the effects of vapor pressure deficit (D) and solar radiation (R(s)) on G(si), much of the remaining variation of reference G(si) (G(siR)) was driven by that of leaf-specific hydraulic conductivity, which in turn was driven by that of A(s)/A(l). After accounting for that effect on G(siR), appreciable temporal variation remained in the decline rate of G(siR) with decreasing vineyard-averaged relative extractable soil water (θ(E)). This variation was related to the differential decline ofθ(E) near each monitored vine, decreasing faster between irrigation events near vines where L was greater, thus adding to the spatiotemporal variation of G(siR) observed in the vineyard. We also found that the vines showed isohydric-like behavior whenθ(E) was low, but switched to anisohydric-like behavior with increasingθ(E). Modeledθ(E) and associated G(s) of a canopy with even L (1.9 m(2) m(-2)) were greater than that of the same average L but split between the lowest and highest L observed along sections of rows in the vineyard (1.2 and 2.6 m(2) m(-2)) by 6 and 12%, respectively. Our results suggest that managing sectional L near the average, rather than allowing a wide variation, can reduce soil water depletion, maintaining G(s) higher, thus potentially enhancing yield.

Variability and trends of wet season temperature in the Sudano-Sahelian zone and relationships with precipitation

NASA Astrophysics Data System (ADS)

Oueslati, Boutheina; Camberlin, Pierre; Zoungrana, Joël; Roucou, Pascal; Diallo, Saliou

2018-02-01

The relationships between precipitation and temperature in the central Sudano-Sahelian belt are investigated by analyzing 50 years (1959-2008) of observed temperature (Tx and Tn) and rainfall variations. At daily time-scale, both Tx and Tn show a marked decrease as a response to rainfall occurrence, with a strongest departure from normal 1 day after the rainfall event (-0.5 to -2.5 °C depending on the month). The cooling is slightly larger when heavy rainfall events (>5 mm) are considered. The temperature anomalies weaken after the rainfall event, but are still significant several days later. The physical mechanisms accounting for the temperature response to precipitation are analysed. The Tx drop is accounted for by reduced incoming solar radiation associated with increased cloud cover and increased surface evaporation following surface moistening. The effect of evaporation becomes dominant a few days after the rainfall event. The reduced daytime heat storage and the subsequent sensible heat flux result in a later negative Tn anomaly. The effect of rainfall variations on temperature is significant for long-term warming trends. The rainfall decrease experienced between 1959 and 2008 accounts for a rainy season Tx increase of 0.15 to 0.3 °C, out of a total Tx increase of 1.3 to 1.5 °C. These results have strong implications on the assessment of future temperature changes. The dampening or amplifying effects of precipitation are determined by the sign of future precipitation trends. Confidence on temperature changes under global warming partly depend on the robustness of precipitation projections.

Eastern North American finite-frequency, compressional and shear tomographic models

NASA Astrophysics Data System (ADS)

Savage, B.; Shen, Y.

2017-12-01

The Eastern North American margin and continental interior is imaged using a finite-frequency, tomographic method. Each of the P and S teleseismic body wave date sets consists of over 80,000 usable measurements recorded on the Transportable Array (TA). Sensitivity kernels are computed from a 1D model with grid spacing of 50 x 50 x 25 km. Measurements are performed automatically at three individual frequency bands, allowing a more effective use of the available broadband data. Imaged shear and compressional wave speeds show similar long-wavelength features of reduced wave speeds along the continent-ocean margin and increased wave speeds within the stable interior. Wave speeds throughout the model are highly variable at the scale of 100 to 200 km. Large wave speed reductions are present near New England, the Mid-Atlantic states, and the Gulf Coast states; these variations are present in previous models. Interestingly, the strongly reduced wave speeds near South Carolina are absent at depths greater than of 150 km within this model and recent teleseismic body-wave models. This result is contrary to a variety of surface wave models which contain an intense, reduced wave speed anomaly extending past 250 km depth and interpreted as a mantle upwelling associated with edge driven convection. An anomaly along the West Virginia-Virginia border, associated with volcanism and mantle upwelling, is also present, tightly constrained, and extends to 200 km depth. Moreover, the interior of the continent contains significant, regional wave speed variations. Variation of this style is present in other surface and body wave models and is not consistent with a massive, homogeneous continent with no internal variations. These internal continental variations suggest a compositional influence as temperature, melt and water are thought to have minimal effect. Unlike surface wave models that include a distinct continental base around 175 km, teleseismic body wave models, including this one, do not show this base. However, this model does include the deep, positive wave speed anomaly within the mantle transition zone interpreted as a slab fragment, agreeing with previous models.

Poster — Thur Eve — 66: Robustness Assessment of a Novel IMRT Planning Method for Lung Radiotherapy

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

Ahanj, M.; Bissonnette, J.-P.; Heath, E.

2014-08-15

Conventional radiotherapy treatment planning for lung cancer accounts for tumour motion by increasing the beam apertures. We recently developed an IMRT planning strategy which uses reduced beam apertures in combination with an edge enhancing boost of 110% of the prescription dose to the volume that corresponds to the portion of the CTV that moves outside of the reduced beam. Previous results showed that this approach ensures target coverage while reducing lung dose. In the current study, we evaluate the robustness of this boost volume approach to changes in respiratory motion, including amplitude and phase weight variations. ITV and boost volumemore » plans were generated for 5 NSCLC patients with respiratory motion amplitudes ranging from 1 to 2 cm. A standard 5mm PTV margin was used for all plans. The ORBIT treatment planning tool was used to plan and accumulate dose over 10 respiratory phases defined by the 4DCT datasets. For the phase weight variation study, dose was accumulated for three scenarios: equally-weighted-phases, higher weight assigned to exhale phases and higher weight assigned to inhale phases. For the amplitude variation study, a numerical phantom was used to generate 4DCT datasets corresponding to 7 mm, 10 mm and 14 mm motion amplitudes. Preliminary results found that delivered plans for all phase weight scenarios were clinically acceptable. When normalized to mean lung dose, the boost volume plan delivered 5% more dose to the CTV which indicates the potential for dose escalation using this approach.« less

Effect of incubation temperature and time on the precision of data generated by antibiotic disc diffusion assays.

PubMed

Smith, P; Kronvall, G

2015-07-01

The influence on the precision of disc diffusion data of the conditions under which the tests were performed was examined by analysing multilaboratory data sets generated after incubation at 35 °C for 18 h, at 28 °C for 24 h and 22 °C for 24 h and 48 h. Analyses of these data sets demonstrated that precision was significantly and progressively decreased as the test temperature was reduced from 35 to 22 °C. Analysis of the data obtained at 22 °C also showed the precision was inversely related to the time of incubation. Temperature and time related decreases in precision were not related to differences in the mean zone sizes of the data sets obtained under these test conditions. Analysis of the zone data obtained at 28 and 22 °C as single laboratory sets demonstrated that reductions of incubation temperature resulted in significant increases in both intralaboratory and interlaboratory variation. Increases in incubation time at 22 °C were, however, associated with statistically significant increases in interlaboratory variation but not with any significant increase in intralaboratory variation. The significance of these observations for the establishment of the acceptable limits of precision of data sets that can be used for the setting of valid epidemiological cut-off values is discussed. © 2014 John Wiley & Sons Ltd.

Equality in Educational Policy and the Heritability of Educational Attainment

PubMed Central

Colodro-Conde, Lucía; Rijsdijk, Frühling; Tornero-Gómez, María J.; Sánchez-Romera, Juan F.; Ordoñana, Juan R.

2015-01-01

Secular variation in the heritability of educational attainment are proposed to be due to the implementation of more egalitarian educational policies leading to increased equality in educational opportunities in the second part of the 20th century. The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents’ education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait. However, this hypothesis has not yet found consistent evidence. Support for this effect relies mainly on comparisons between countries adopting different educational systems or between different time periods within a country reflecting changes in general policy. Using a population-based sample of 1271 pairs of adult twins, we analyzed the effect of the introduction of a specific educational policy in Spain in 1970. The shared-environmental variance decreased, leading to an increase in heritability in the post-reform cohort (44 vs. 67%) for males. Unstandardized estimates of genetic variance were of a similar magnitude (.56 vs. .57) between cohorts, while shared environmental variance decreased from .56 to .04. Heritability remained in the same range for women (40 vs. 34%). Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin. PMID:26618539

Long-term effects of nickel oxide nanoparticles on performance, microbial enzymatic activity, and microbial community of a sequencing batch reactor.

PubMed

Wang, Sen; Li, Zhiwei; Gao, Mengchun; She, Zonglian; Guo, Liang; Zheng, Dong; Zhao, Yangguo; Ma, Bingrui; Gao, Feng; Wang, Xuejiao

2017-02-01

The nitrogen and phosphorus removal, microbial enzymatic activity, and microbial community of a sequencing batch reactor (SBR) were evaluated under long-term exposure to nickel oxide nanoparticles (NiO NPs). High NiO NP concentration (over 5 mg L -1 ) affected the removal of chemical oxygen demand, nitrogen, and phosphorus. The presence of NiO NP inhibited the microbial enzymatic activities and reduced the nitrogen and phosphorus removal rates of activated sludge. The microbial enzymatic activities of the activated sludge showed a similar variation trend to the nitrogen and phosphorus removal rates with the increase in NiO NP concentration from 0 to 60 mg L -1 . The Ni content in the effluent and activated sludge showed an increasing trend with the increase in NiO NP concentration. Some NiO NPs were absorbed on the sludge surface or penetrate the cell membrane into the interior of microbial cells in the activated sludge. NiO NP facilitated the increase in reactive oxygen species by disturbing the balance between the oxidation and anti-oxidation processes, and the variation in lactate dehydrogenase demonstrated that NiO NP could destroy the cytomembrane and cause variations in the microbial morphology and physiological function. High-throughput sequencing demonstrated that the microbial community of SBR had some obvious changes at 0-60 mg L -1 NiO NPs at the phyla, class and genus levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Warm water temperatures and shifts in seasonality increase trout recruitment but only moderately decrease adult size in western North American tailwaters

USGS Publications Warehouse

Dibble, Kimberly L.; Yackulic, Charles B.; Kennedy, Theodore A.

2018-01-01

Dams throughout western North America have altered thermal regimes in rivers, creating cold, clear “tailwaters” in which trout populations thrive. Ongoing drought in the region has led to highly publicized reductions in reservoir storage and raised concerns about potential reductions in downstream flows. Large changes in riverine thermal regimes may also occur as reservoir water levels drop, yet this potential impact has received far less attention. We analyzed historic water temperature and fish population data to anticipate how trout may respond to future changes in the magnitude and seasonality of river temperatures. We found that summer temperatures were inversely related to reservoir water level, with warm temperatures associated with reduced storage and with dams operated as run-of-river units. Variation in rainbow trout (Oncorhynchus mykiss) recruitment was linked to water temperature variation, with a 5-fold increase in recruitment occurring at peak summer temperatures (18 °C vs. 7 °C) and a 2.5-fold increase in recruitment when peak temperatures occurred in summer rather than fall. Conversely, adult trout size was only moderately related to temperature. Rainbow and brown trout (Salmo trutta) size decreased by ~24 mm and 20 mm, respectively, as mean annual and peak summer temperatures increased. Further, rainbow trout size decreased by ~29 mm with an earlier onset of cold winter temperatures. While increased recruitment may be the more likely outcome of a warmer and drier climate, density-dependent growth constraints could exacerbate temperature-dependent growth reductions. As such, managers may consider implementing flows to reduce recruitment or altering infrastructure to maintain coldwater reservoir releases.

Photosynthesis and carbon allocation are both important predictors of genotype productivity responses to elevated CO2 in Eucalyptus camaldulensis.

PubMed

Aspinwall, Michael J; Blackman, Chris J; de Dios, Víctor Resco; Busch, Florian A; Rymer, Paul D; Loik, Michael E; Drake, John E; Pfautsch, Sebastian; Smith, Renee A; Tjoelker, Mark G; Tissue, David T

2018-05-08

Intraspecific variation in biomass production responses to elevated atmospheric carbon dioxide (eCO2) could influence tree species' ecological and evolutionary responses to climate change. However, the physiological mechanisms underlying genotypic variation in responsiveness to eCO2 remain poorly understood. In this study, we grew 17 Eucalyptus camaldulensis Dehnh. subsp. camaldulensis genotypes (representing provenances from four different climates) under ambient atmospheric CO2 and eCO2. We tested whether genotype leaf-scale photosynthetic and whole-tree carbon (C) allocation responses to eCO2 were predictive of genotype biomass production responses to eCO2. Averaged across genotypes, growth at eCO2 increased in situ leaf net photosynthesis (Anet) (29%) and leaf starch concentrations (37%). Growth at eCO2 reduced the maximum carboxylation capacity of Rubisco (-4%) and leaf nitrogen per unit area (Narea, -6%), but Narea calculated on a total non-structural carbohydrate-free basis was similar between treatments. Growth at eCO2 also increased biomass production and altered C allocation by reducing leaf area ratio (-11%) and stem mass fraction (SMF, -9%), and increasing leaf mass area (18%) and leaf mass fraction (5%). Overall, we found few significant CO2 × provenance or CO2 × genotype (within provenance) interactions. However, genotypes that showed the largest increases in total dry mass at eCO2 had larger increases in root mass fraction (with larger decreases in SMF) and photosynthetic nitrogen-use efficiency (PNUE) with CO2 enrichment. These results indicate that genetic differences in PNUE and carbon sink utilization (in roots) are both important predictors of tree productivity responsiveness to eCO2.

Nitrogen split dose fertilization, plant age and frost effects on phytochemical content and sensory properties of curly kale (Brassica oleracea L. var. sabellica).

PubMed

Groenbaek, Marie; Jensen, Sidsel; Neugart, Susanne; Schreiner, Monika; Kidmose, Ulla; Kristensen, Hanne L

2016-04-15

We investigated how concentrations of sensory relevant compounds: glucosinolates (GLSs), flavonoid glycosides, hydroxycinnamic acid derivatives and sugars in kale responded to split dose and reduced nitrogen (N) fertilization, plant age and controlled frost exposure. In addition, frost effects on sensory properties combined with N supply were assessed. Seventeen week old kale plants showed decreased aliphatic GLSs at split dose N fertilization; whereas reduced N increased aliphatic and total GLSs. Ontogenetic effects were demonstrated for all compounds: sugars, aliphatic and total GLSs increased throughout plant development, whereas kaempferol and total flavonoid glycosides showed higher concentrations in 13 week old plants. Controlled frost exposure altered sugar composition slightly, but not GLSs or flavonoid glycosides. Reduced N supply resulted in less bitterness, astringency and pungent aroma, whereas frost exposure mainly influenced aroma and texture. N treatment explained most of the sensory variation. Producers should not rely on frost only to obtain altered sensory properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Colorectal cancer disparities beyond biology: Screening, treatment, access.

PubMed

Daniel, Casey L; Gilreath, Kelly; Keyes, Danielle

2017-01-01

African Americans in the United States are more likely than their white counterparts to experience greater incidence and mortality due to colorectal cancer (CRC). Present for decades, these disparities have prompted researchers to investigate underlying causes and potential explanations. While some biological variations have been observed between races, evidence shows that approximately 50% of these disparities can be attributed to differences and disparities in CRC screening, resulting in reduced polyp removal for CRC prevention and/or early detection of CRC among African Americans. Other major contributors to CRC disparities are differences in treatment and access to care. Significant efforts are needed to increase CRC screening among African Americans through targeted interventions to reduce barriers such as increasing education, promoting physician recommendations, and providing affordable and quality care. Intervention is also needed to educate the medical community about these issues and to change health policy to provide a multilevel approach with the best chance of success in reducing racial disparities in CRC.

Dependence of recycling and edge profiles on lithium evaporation in high triangularity, high performance NSTX H-mode discharges.

DOE PAGES

Maingi, R.; Osborne, T. H.; Bell, M. G.; ...

2014-11-04

In this paper, the effects of a pre-discharge lithium evaporation variation on highly shaped discharges in the National Spherical Torus Experiment (NSTX) are documented. Lithium wall conditioning (‘dose’) was routinely applied onto graphite plasma facing components between discharges in NSTX, partly to reduce recycling. Reduced D α emission from the lower and upper divertor and center stack was observed, as well as reduced midplane neutral pressure; the magnitude of reduction increased with the pre-discharge lithium dose. Improved energy confinement, both raw τ E and H-factor normalized to scalings, with increasing lithium dose was also observed. At the highest doses, wemore » also observed elimination of edge-localized modes. The midplane edge plasma profiles were dramatically altered, comparable to lithium dose scans at lower shaping, where the strike point was farther from the lithium deposition centroid. As a result, this indicates that the benefits of lithium conditioning should apply to the highly shaped plasmas planned in NSTX-U.« less

Improving cereal grain carbohydrates for diet and health

PubMed Central

Lafiandra, Domenico; Riccardi, Gabriele; Shewry, Peter R.

2014-01-01

Starch and cell wall polysaccharides (dietary fibre) of cereal grains contribute to the health benefits associated with the consumption of whole grain cereal products, including reduced risk of obesity, type 2 diabetes, cardiovascular disease and colorectal cancer. The physiological bases for these effects are reviewed in relation to the structures and physical properties of the polysaccharides and their behaviour (including digestion and fermentation) in the gastro-intestinal tract. Strategies for modifying the content and composition of grain polysaccharides to increase their health benefits are discussed, including exploiting natural variation and using mutagenesis and transgenesis to generate further variation. These studies will facilitate the development of new types of cereals and cereal products to face the major health challenges of the 21st century. PMID:24966450

Analysis of Variations in Hospital Use by Medicare Patients in Psro Areas, 1974-1977

PubMed Central

Deacon, Ronald; Lubitz, James; Gornick, Marian; Newton, Marilyn

1979-01-01

A study of the use of short-stay hospitals in PSRO areas by Medicare enrollees aged 65 and over for the period 1974 through 1977 revealed that discharge rates increased, average length of stay (ALOS) decreased, and days-of-care rates remained relatively constant in nearly all of the PSRO areas. The data show large variations in hospital use in PSRO areas within States and HEW regions, and suggest that factors within the area are critical determinants of hospital utilization. This study presents important implications for PSRO program policy for it suggests that factors other than physician and hospital behavior should also be considered when setting objectives for reducing misutilization and improving the quality of health care. PMID:10309054

Ion Monitoring

DOEpatents

Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore

2003-11-18

The apparatus and method provide a technique for significantly reducing capacitance effects in detector electrodes arising due to movement of the instrument relative to the item/location being monitored in ion detection based techniques. The capacitance variations are rendered less significant by placing an electrically conducting element between the detector electrodes and the monitored location/item. Improved sensitivity and reduced noise signals arise as a result. The technique also provides apparatus and method suitable for monitoring elongate items which are unsuited to complete enclosure in one go within a chamber. The items are monitored part by part as the pass through the instrument, so increasing the range of items or locations which can be successfully monitored.

Effect of reducing rotor blade inlet diameter on the performance of a 11.66-Centimeter radial-inflow turbine

NASA Technical Reports Server (NTRS)

Kofskey, M. G.; Haas, J. E.

1973-01-01

The effect of increased rotor blade loading on turbine performance was investigated by reducing rotor blade inlet diameter. The reduction was made in four stages. Each modification was tested with the same stator using cold air as the working fluid. Results are presented in terms of equivalent mass flow and efficiency at equivalent design rotative speed and over a range of pressure ratios. Internal flow characteristics are shown in terms of stator exit static pressure and the radial variation of local loss and rotor-exit flow angle with radius ratio. Included are velocity diagrams calculated from the experimental results.

Mission Implementation Constraints on Planetary Muon Radiography

NASA Technical Reports Server (NTRS)

Jones, Cathleen E.; Kedar, Sharon; Naudet, Charles; Webb, Frank

2011-01-01

Cost: Use heritage hardware, especially use a tested landing system to reduce cost (Phoenix or MSL EDL stage). The sky crane technology delivers higher mass to the surface and enables reaching targets at higher elevation, but at a higher mission cost. Rover vs. Stationary Lander: Rover-mounted instrument enables tomography, but the increased weight of the rover reduces the allowable payload weight. Mass is the critical design constraint for an instrument for a planetary mission. Many factors that are minor factors or do not enter into design considerations for terrestrial operation are important for a planetary application. (Landing site, diurnal temperature variation, instrument portability, shock/vibration)

Pharmaceutical companies' variation of drug prices within and among countries can improve long-term social well-being.

PubMed

Lichtenberg, Frank R

2011-08-01

Drug prices vary considerably across and within countries. On average, pharmaceutical companies charge lower prices in low-income countries than in industrialized nations. Manufacturers' ability to price products differently for different markets--a practice known as price discrimination--increases their profits overall. But it is also likely to result in greater investment in research and development, and therefore in more new drugs on the market. Although reducing price discrimination in order to cut costs might benefit consumers in the short run, it would harm them in the long run by reducing the number of new drugs developed.

Genotypic Diversity and Short-term Response to Shading Stress in a Threatened Seagrass: Does Low Diversity Mean Low Resilience?

PubMed

Evans, Suzanna M; Vergés, Adriana; Poore, Alistair G B

2017-01-01

Seagrasses that are predominantly clonal often have low levels of genetic variation within populations and predicting their response to changing conditions requires an understanding of whether genetic variation confers increased resistance to environmental stressors. A higher level of genetic diversity is assumed to benefit threatened species due to the increased likelihood of those populations having genotypes that can persist under environmental change. To test this idea, we conducted an in situ shading experiment with six geographically distinct meadows of the threatened seagrass Posidonia australis that vary in genetic diversity. Different genotypes within meadows varied widely in their physiological and growth responses to reduced light during a simulated short-term turbidity event. The majority of meadows were resistant to the sudden reduction in light availability, but a small subset of meadows with low genotypic diversity were particularly vulnerable to the early effects of shading, showing substantially reduced growth rates after only 3 weeks. Using the photosynthetic performance (maximum quantum yield) of known genotypes, we simulated meadows of varying genetic diversity to show that higher diversity can increase meadow resilience to stress by ensuring a high probability of including a high-performing genotype. These results support the hypothesis that complementarity among genotypes enhances the adaptive capacity of a population, and have significant implications for the conservation of declining P. australis meadows close to the species range edge on the east coast of Australia, where the genotypic diversity is low.

Variations in large-scale tropical cyclone genesis factors over the western North Pacific in the PMIP3 last millennium simulations

NASA Astrophysics Data System (ADS)

Yan, Qing; Wei, Ting; Zhang, Zhongshi

2017-02-01

Investigation of past tropical cyclone (TC) activity in the Western North Pacific (WNP) is potentially helpful to enable better understanding of future TC behaviors. In this study, we examine variations in large-scale environmental factors important to TC genesis in the last millennium simulations from the Paleoclimate Modelling Intercomparison Project Phase 3 (PMIP3). The results show that potential intensity, a theoretical prediction of the maximum TC intensity, is increased relative to the last millennium in the north part of the WNP in the Medieval Climate Anomaly (MCA; 950-1200 AD) while it is decreased in the Little Ice Age (LIA; 1600-1850 AD). Vertical wind shear that generally inhibits TC genesis is enhanced (reduced) to the south of 20°N and is reduced (enhanced) to the north in the MCA (LIA). Relative humidity (at 600 hPa) that measures the mid-tropospheric moisture content broadly shows an increase (decrease) in the MCA (LIA). A genesis potential index indicates that conditions are generally favorable (unfavorable) for TC formation in the WNP in the MCA (LIA), especially in the northern part. Taking changes in steering flows into account, there may be an increasing (decreasing) favorability for storm strikes in East Asia in the MCA (LIA). The estimated TC activity is consistent with the geological proxies in Japan, but contradicts with the typhoon records in southern China and Taiwan. This model-data discrepancy is attributed to the limitations in both simulations and reconstructions.

Genetic variation in brown fat activity and body weight regulation in mice: lessons for human studies.

PubMed

Kozak, Leslie P

2014-03-01

The recent characterization of brown fat in humans has generated much excitement on the possibility that increased energy expenditure by heat production by this tissue will be able to reduce obesity. This expectation has largely been stimulated by studies with mice that show strong associations between increased brown fat activity and reductions in obesity and insulin resistance. Research in the mouse has been largely based upon the induction or suppression of brown fat and mitochondrial uncoupling protein by genetic methods. The review of this research literature underscores the idea that reductions in obesity in mice are secondary to the primary role of brown adipose tissue in the regulation of body temperature. Given that the variation in brown fat in humans, as detected by PET imaging, is highly associated with administration of adrenergic agonists and reductions in ambient temperature, the effects on obesity in humans may also be secondary to the regulation of body temperature. Induction of thermogenesis by reduced ambient temperature now becomes like muscle and physical activity, another natural method of increased energy expenditure to combat obesity. Furthermore, there is no evidence to indicate that heat production by adrenergic stimulation via cold exposure or drug treatment or the enriched physical environment is restricted to the thermogenic activity of the brown adipocyte. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease. Copyright © 2013 Elsevier B.V. All rights reserved.

Genotypic Diversity and Short-term Response to Shading Stress in a Threatened Seagrass: Does Low Diversity Mean Low Resilience?

PubMed Central

Evans, Suzanna M.; Vergés, Adriana; Poore, Alistair G. B.

2017-01-01

Seagrasses that are predominantly clonal often have low levels of genetic variation within populations and predicting their response to changing conditions requires an understanding of whether genetic variation confers increased resistance to environmental stressors. A higher level of genetic diversity is assumed to benefit threatened species due to the increased likelihood of those populations having genotypes that can persist under environmental change. To test this idea, we conducted an in situ shading experiment with six geographically distinct meadows of the threatened seagrass Posidonia australis that vary in genetic diversity. Different genotypes within meadows varied widely in their physiological and growth responses to reduced light during a simulated short-term turbidity event. The majority of meadows were resistant to the sudden reduction in light availability, but a small subset of meadows with low genotypic diversity were particularly vulnerable to the early effects of shading, showing substantially reduced growth rates after only 3 weeks. Using the photosynthetic performance (maximum quantum yield) of known genotypes, we simulated meadows of varying genetic diversity to show that higher diversity can increase meadow resilience to stress by ensuring a high probability of including a high-performing genotype. These results support the hypothesis that complementarity among genotypes enhances the adaptive capacity of a population, and have significant implications for the conservation of declining P. australis meadows close to the species range edge on the east coast of Australia, where the genotypic diversity is low. PMID:28855915

Circadian variation in the circulatory responses to exercise: relevance to the morning peaks in strokes and cardiac events

PubMed Central

2009-01-01

Sudden cardiac and cerebral events are most common in the morning. A fundamental question is whether these events are triggered by the increase in physical activity after waking, and/or a result of circadian variation in the responses of circulatory function to exercise. Although signaling pathways from the master circadian clock in the suprachiasmatic nuclei to sites of circulatory control are not yet understood, it is known that cerebral blood flow, autoregulation and cerebrovascular reactivity to changes in CO2 are impaired in the morning and, therefore, could explain the increased risk of cerebrovascular events. Blood pressure (BP) and the rate pressure product (RPP) show marked ‘morning surges’ when people are studied in free-living conditions, making the rupture of a fragile atherosclerotic plaque and sudden cardiac event more likely. Since cerebral autoregulation is reduced in the morning, this surge in BP may also exacerbate the risk of hemorrhagic and ischemic strokes in the presence of other acute and chronic risk factors. Increased sympathetic activity, decreased endothelial function, and increased platelet aggregability could also be important in explaining the morning peak in cardiac and cerebral events but how these factors respond to exercise at different times of day is unclear. Evidence is emerging that the exercise-related responses of BP and RPP are increased in the morning when prior sleep is controlled. We recommend that such ‘semi-constant routine’ protocols are employed to examine the relative influence of the body clock and exogenous factors on the 24-h variation in other circulatory factors. PMID:19826832

Speckle reduction in optical coherence tomography by adaptive total variation method

NASA Astrophysics Data System (ADS)

Wu, Tong; Shi, Yaoyao; Liu, Youwen; He, Chongjun

2015-12-01

An adaptive total variation method based on the combination of speckle statistics and total variation restoration is proposed and developed for reducing speckle noise in optical coherence tomography (OCT) images. The statistical distribution of the speckle noise in OCT image is investigated and measured. With the measured parameters such as the mean value and variance of the speckle noise, the OCT image is restored by the adaptive total variation restoration method. The adaptive total variation restoration algorithm was applied to the OCT images of a volunteer's hand skin, which showed effective speckle noise reduction and image quality improvement. For image quality comparison, the commonly used median filtering method was also applied to the same images to reduce the speckle noise. The measured results demonstrate the superior performance of the adaptive total variation restoration method in terms of image signal-to-noise ratio, equivalent number of looks, contrast-to-noise ratio, and mean square error.

Testing genotypic variation of an invasive plant species in response to soil disturbance and herbivory.

PubMed

Bayliss, Shannon L J; terHorst, Casey P; Lau, Jennifer A

2017-04-01

Herbivores, competitors, and predators can inhibit biological invasions ("biotic resistance" sensu Elton 1959), while disturbance typically promotes biological invasions. Although biotic resistance and disturbance are often considered separately in the invasion literature, these two forces may be linked. One mechanism by which disturbance may facilitate biological invasions is by decreasing the effectiveness of biotic resistance. The effects of both disturbance and biotic resistance may vary across invading genotypes, and genetic variation in the invasive propagule pool may increase the likelihood that some genotypes can overcome biotic resistance or take greater advantage of disturbance. We conducted an experimental field trial in which we manipulated soil disturbance (thatch removal and loosening soil) and the presence of insect herbivores and examined their effects on the invasion success of 44 Medicago polymorpha genotypes. As expected, insecticide reduced leaf damage and increased Medicago fecundity, suggesting that insect herbivores in this system provide some biotic resistance. Soil disturbance increased Medicago fecundity, but did not alter the effectiveness of biotic resistance by insect herbivores. We found significant genetic variation in Medicago in response to disturbance, but not in response to insect herbivores. These results suggest that the ability of Medicago to invade particular habitats depends on the amount of insect herbivory, the history of disturbance in the habitat, and how the specific genotypes in the invader pool respond to these factors.

Mitochondrial DNA Variant in COX1 Subunit Significantly Alters Energy Metabolism of Geographically Divergent Wild Isolates in Caenorhabditis elegans

PubMed Central

Dingley, Stephen D.; Polyak, Erzsebet; Ostrovsky, Julian; Srinivasan, Satish; Lee, Icksoo; Rosenfeld, Amy B.; Tsukikawa, Mai; Xiao, Rui; Selak, Mary A.; Coon, Joshua J.; Hebert, Alexander S.; Grimsrud, Paul A.; Kwon, Young Joon; Pagliarini, David J.; Gai, Xiaowu; Schurr, Theodore G.; Hüttemann, Maik; Nakamaru-Ogiso, Eiko; Falk, Marni J.

2014-01-01

Mitochondrial DNA (mtDNA) sequence variation can influence the penetrance of complex diseases and climatic adaptation. While studies in geographically defined human populations suggest that mtDNA mutations become fixed when they have conferred metabolic capabilities optimally suited for a specific environment, it has been challenging to definitively assign adaptive functions to specific mtDNA sequence variants in mammals. We investigated whether mtDNA genome variation functionally influences Caenorhabditis elegans wild isolates of distinct mtDNA lineages and geographic origins. We found that, relative to N2 (England) wild-type nematodes, CB4856 wild isolates from a warmer native climate (Hawaii) had a unique p.A12S amino acid substitution in the mtDNA-encoded COX1 core catalytic subunit of mitochondrial complex IV (CIV). Relative to N2, CB4856 worms grown at 20 °C had significantly increased CIV enzyme activity, mitochondrial matrix oxidant burden, and sensitivity to oxidative stress but had significantly reduced lifespan and mitochondrial membrane potential. Interestingly, mitochondrial membrane potential was significantly increased in CB4856 grown at its native temperature of 25 °C. A transmitochondrial cybrid worm strain, chpIR (M, CB4856 > N2), was bred as homoplasmic for the CB4856 mtDNA genome in the N2 nuclear background. The cybrid strain also displayed significantly increased CIV activity, demonstrating that this difference results from the mtDNA-encoded p.A12S variant. However, chpIR (M, CB4856 > N2) worms had significantly reduced median and maximal lifespan relative to CB4856, which may relate to their nuclear– mtDNA genome mismatch. Overall, these data suggest that C. elegans wild isolates of varying geographic origins may adapt to environmental challenges through mtDNA variation to modulate critical aspects of mitochondrial energy metabolism. PMID:24534730

Structure-mechanical function relations at nano-scale in heat-affected human dental tissue.

PubMed

Sui, Tan; Sandholzer, Michael A; Le Bourhis, Eric; Baimpas, Nikolaos; Landini, Gabriel; Korsunsky, Alexander M

2014-04-01

The knowledge of the mechanical properties of dental materials related to their hierarchical structure is essential for understanding and predicting the effect of microstructural alterations on the performance of dental tissues in the context of forensic and archaeological investigation as well as laser irradiation treatment of caries. So far, few studies have focused on the nano-scale structure-mechanical function relations of human teeth altered by chemical or thermal treatment. The response of dental tissues to thermal treatment is thought to be strongly affected by the mineral crystallite size, their spatial arrangement and preferred orientation. In this study, synchrotron-based small and wide angle X-ray scattering (SAXS/WAXS) techniques were used to investigate the micro-structural alterations (mean crystalline thickness, crystal perfection and degree of alignment) of heat-affected dentine and enamel in human dental teeth. Additionally, nanoindentation mapping was applied to detect the spatial and temperature-dependent nano-mechanical properties variation. The SAXS/WAXS results revealed that the mean crystalline thickness distribution in dentine was more uniform compared with that in enamel. Although in general the mean crystalline thickness increased both in dentine and enamel as the temperature increased, the local structural variations gradually reduced. Meanwhile, the hardness and reduced modulus in enamel decreased as the temperature increased, while for dentine, the tendency reversed at high temperature. The analysis of the correlation between the ultrastructure and mechanical properties coupled with the effect of temperature demonstrates the effect of mean thickness and orientation on the local variation of mechanical property. This structural-mechanical property alteration is likely to be due to changes of HAp crystallites, thus dentine and enamel exhibit different responses at different temperatures. Our results enable an improved understanding of the mechanical properties correlation in hierarchical biological materials, and human dental tissue in particular. Copyright © 2013 Elsevier Ltd. All rights reserved.

A stochastic-advective transport model for NAPL dissolution and degradation in non-uniform flows in porous media

NASA Astrophysics Data System (ADS)

Chan, T. P.; Govindaraju, Rao S.

2006-10-01

Remediation schemes for contaminated sites are often evaluated to assess their potential for source zone reduction of mass, or treatment of the contaminant between the source and a control plane (CP) to achieve regulatory limits. In this study, we utilize a stochastic stream tube model to explain the behavior of breakthrough curves (BTCs) across a CP. At the local scale, mass dissolution at the source is combined with an advection model with first-order decay for the dissolved plume. Field-scale averaging is then employed to account for spatial variation in mass within the source zone, and variation in the velocity field. Under the assumption of instantaneous mass transfer from the source to the moving liquid, semi-analytical expressions for the BTC and temporal moments are developed, followed by derivation of expressions for effective velocity, dispersion, and degradation coefficients using the method of moments. It is found that degradation strongly influences the behavior of moments and the effective parameters. While increased heterogeneity in the velocity field results in increased dispersion, degradation causes the center of mass of the plume to shift to earlier times, and reduces the dispersion of the BTC by lowering the concentrations in the tail. Modified definitions of effective parameters are presented for degrading solutes to account for the normalization constant (zeroth moment) that keeps changing with time or distance to the CP. It is shown that anomalous dispersion can result for high degradation rates combined with wide variation in velocity fluctuations. Implications of model results on estimating cleanup times and fulfillment of regulatory limits are discussed. Relating mass removal at the source to flux reductions past a control plane is confounded by many factors. Increased heterogeneity in velocity fields causes mass fluxes past a control plane to persist, however, aggressive remediation between the source and CP can reduce these fluxes.

Semi-active control of helicopter vibration using controllable stiffness and damping devices

NASA Astrophysics Data System (ADS)

Anusonti-Inthra, Phuriwat

Semi-active concepts for helicopter vibration reduction are developed and evaluated in this dissertation. Semi-active devices, controllable stiffness devices or controllable orifice dampers, are introduced; (i) in the blade root region (rotor-based concept) and (ii) between the rotor and the fuselage as semi-active isolators (in the non-rotating frame). Corresponding semi-active controllers for helicopter vibration reduction are also developed. The effectiveness of the rotor-based semi-active vibration reduction concept (using stiffness and damping variation) is demonstrated for a 4-bladed hingeless rotor helicopter in moderate- to high-speed forward flight. A sensitivity study shows that the stiffness variation of root element can reduce hub vibrations when proper amplitude and phase are used. Furthermore, the optimal semi-active control scheme can determine the combination of stiffness variations that produce significant vibration reduction in all components of vibratory hub loads simultaneously. It is demonstrated that desired cyclic variations in properties of the blade root region can be practically achieved using discrete controllable stiffness devices and controllable dampers, especially in the flap and lag directions. These discrete controllable devices can produce 35--50% reduction in a composite vibration index representing all components of vibratory hub loads. No detrimental increases are observed in the lower harmonics of blade loads and blade response (which contribute to the dynamic stresses) and controllable device internal loads, when the optimal stiffness and damping variations are introduced. The effectiveness of optimal stiffness and damping variations in reducing hub vibration is retained over a range of cruise speeds and for variations in fundamental rotor properties. The effectiveness of the semi-active isolator is demonstrated for a simplified single degree of freedom system representing the semi-active isolation system. The rotor, represented by a lumped mass under harmonic force excitation, is supported by a spring and a parallel damper on the fuselage (assumed to have infinite mass). Properties of the spring or damper can then be controlled to reduce transmission of the force into the fuselage or the support structure. This semi-active isolation concept can produce additional 30% vibration reduction beyond the level achieved by a passive isolator. Different control schemes (i.e. open-loop, closed-loop, and closed-loop adaptive schemes) are developed and evaluated to control transmission of vibratory loads to the support structure (fuselage), and it is seen that a closed-loop adaptive controller is required to retain vibration reduction effectiveness when there is a change in operating condition. (Abstract shortened by UMI.)

Seasonal and interannual variations of top-of-atmosphere irradiance and cloud cover over polar regions derived from the CERES data set

NASA Astrophysics Data System (ADS)

Kato, Seiji; Loeb, Norman G.; Minnis, Patrick; Francis, Jennifer A.; Charlock, Thomas P.; Rutan, David A.; Clothiaux, Eugene E.; Sun-Mack, Szedung

2006-10-01

The daytime cloud fraction derived by the Clouds and the Earth's Radiant Energy System (CERES) cloud algorithm using Moderate Resolution Imaging Spectroradiometer (MODIS) radiances over the Arctic from March 2000 through February 2004 increases at a rate of 0.047 per decade. The trend is significant at an 80% confidence level. The corresponding top-of-atmosphere (TOA) shortwave irradiances derived from CERES radiance measurements show less significant trend during this period. These results suggest that the influence of reduced Arctic sea ice cover on TOA reflected shortwave radiation is reduced by the presence of clouds and possibly compensated by the increase in cloud cover. The cloud fraction and TOA reflected shortwave irradiance over the Antarctic show no significant trend during the same period.

Variation in Wolbachia effects on Aedes mosquitoes as a determinant of invasiveness and vectorial capacity.

PubMed

King, Jessica G; Souto-Maior, Caetano; Sartori, Larissa M; Maciel-de-Freitas, Rafael; Gomes, M Gabriela M

2018-04-16

Wolbachia has been introduced into Aedes aegypti mosquitoes to control the spread of arboviruses, such as dengue, chikungunya and Zika. Studies showed that certain Wolbachia strains (such as wMel) reduce replication of dengue viruses in the laboratory, prompting the release of mosquitoes carrying the bacterium into the field, where vectorial capacity can be realistically assessed in relation to native non-carriers. Here we apply a new analysis to two published datasets, and show that wMel increases the mean and the variance in Ae. aegypti susceptibility to dengue infection when introgressed into Brazil and Vietnam genetic backgrounds. In the absence of other processes, higher mean susceptibility should lead to enhanced viral transmission. The increase in variance, however, widens the basis for selection imposed by unexplored natural forces, retaining the potential for reducing transmission overall.

Susceptibility of early life stages of Xenopus laevis to cadmium

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

Herkovits, J.; Perez-Coll, C.S.; Cardellini, P.

1997-02-01

The susceptibility of Xenopus laevis to cadmium during different stages of development was evaluated by exposing embryos to cadmium concentrations ranging from 0.1 to 10 mg Cd{sup 2+}/L for 24, 48, and 72 h and assessing lethality and malformations. Susceptibility increased from the two blastomeres stage (stage 2) to stage 40, in which the 24-h LC100 was 1.13 mg Cd{sup 2+}/L, and resistance increased from this stage onward. Malformations occurred at all developmental stages evaluated, the most common being reduced size, incurvated axis, underdeveloped or abnormally developed fin, microcephaly, and microphtalmy. Scanning electron microscopy revealed changes in the ectodermal surfacemore » ranging from slightly vaulted cells to a severe reduction in the number of ciliated cells as the concentration of cadmium increased. The intraspecific variation evaluated in embryos (from four sets of parents) at seven developmental stages, expressed as the coefficient of variation of the LC100, ranged from 10 to 112% and reflects the capacity of Xenopus laevis to adapt to changing environmental conditions at different embryonic stages.« less

Analysis of 1970-1995 Trends in Tropospheric Ozone at Northern Hemisphere Midlatitudes with the GEOS-CHEM Model

NASA Technical Reports Server (NTRS)

Fusco, Andrew C.; Logan, Jennifer A.

2004-01-01

I ] The causes of trends in tropospheric ozone at Northern Hemisphere midlatitudes from 1970 to 1995 are investigated with the GEOS-CHEM model, a global three-dimensional model of the troposphere driven by assimilated meteorological observations from the Goddard Earth Observing System (GEOS). This model is used to investigate the sensitivity of tropospheric ozone with respect to (1) changes in the anthropogenic emission of nitrogen oxides and nonmethane hydrocarbons, (2) increases in methane concentrations, (3) variations in the stratospheric source of ozone, (4) changes in solar radiation resulting from stratospheric ozone depletion, and ( 5 ) increases in tropospheric temperatures. Model results indicate that local increases in NO, emissions have caused most of the increases seen in lower tropospheric ozone over Europe and Japan. Increases in methane are responsible for roughly one fifth of the anthropogenically induced increase in tropospheric ozone at northern midlatitudes. However, changes in ozone precursors do not adequately explain either the spatial differences in observed ozone trends across midlatitudes or the observed decreases in ozone over Canada throughout the troposphere. We argue that ozone depletion in the lowermost stratosphere is likely to have reduced the stratospheric source by as much as 30% from the early 1970s to the mid 1990s. Model simulations that account for such a reduction along with reported changes in anthropogenic emissions show steep declines of ozone in the upper troposphere and variable increases in the lower troposphere that are more consistent with observations. Differential temperature trends in summer between North America and Europe may account for at least some of the remaining spatial variation in tropospheric ozone trends. Increases in ultraviolet (UV) radiation due to stratospheric ozone depletion do not appear to significantly reduce tropospheric ozone, except at midlatitudes in the Southern Hemisphere following the breakup of the ozone hole.

Reducing risk and increasing confidence of decision making at a lower cost: In-situ pXRF assessment of metal-contaminated sites.

PubMed

Rouillon, Marek; Taylor, Mark P; Dong, Chenyin

2017-10-01

This study evaluates the in-situ use of field portable X-ray Fluorescence (pXRF) for metal-contaminated site assessments, and assesses the advantages of increased sampling to reduce risk, and increase confidence of decision making at a lower cost. Five metal-contaminated sites were assessed using both in-situ pXRF and ex-situ inductively coupled plasma mass spectrometry (ICP-MS) analyses at various sampling resolutions. Twenty second in-situ pXRF measurements of Mn, Zn and Pb were corrected using a subset of parallel ICP-MS measurements taken at each site. Field and analytical duplicates revealed sampling as the major contributor (>95% variation) to measurement uncertainties. This study shows that increased sampling led to several benefits including more representative site characterisation, higher soil-metal mapping resolution, reduced uncertainty around the site mean, and reduced sampling uncertainty. Real time pXRF data enabled efficient, on-site decision making for further judgemental sampling, without the need to return to the site. Additionally, in-situ pXRF was more cost effective than the current approach of ex-situ sampling and ICP-MS analysis, even with higher sampling at each site. Lastly, a probabilistic site assessment approach was applied to demonstrate the advantages of integrating estimated measurement uncertainties into site reporting. Copyright © 2017 Elsevier Ltd. All rights reserved.

The case for restraint in spinal surgery: does quality management have a role to play?

PubMed Central

Mirza, Sohail K.

2009-01-01

Most quality improvement efforts in surgery have focused on the technical quality of care provided, rather than whether the care was indicated, or could have been provided with a safer procedure. Because risk is inherent in any procedure, reducing the number of unnecessary operations is an important issue in patient safety. In the case of lumbar spine surgery, several lines of evidence suggest that, in at least some locations, there may be excessively high surgery rates. This evidence comes from international comparisons of surgical rates; study of small area variations within countries; increasing surgical rates in the absence of new indications; comparisons of surgical outcomes between geographic areas with high or low surgical rates; expert opinion; the preferences of well-informed patients; and increasing rates of repeat surgery. From a population perspective, reducing unnecessary surgery may have a greater impact on complication rates than improving the technical quality of surgery that is performed. Evidence suggests this may be true for coronary bypass surgery in the US and hysterectomy rates in Canada. Though similar studies have not been done for spine surgery, wide geographic variations in surgical rates suggest that this could be the case for spine surgery as well. We suggest that monitoring geographic variations in surgery rates may become an important aspect of quality improvement, and that rates of repeat surgery may bear special attention. Patient registries can help in this regard, if they are very complete and rigorously maintained. They can provide data on surgical rates; offer post-marketing surveillance for new surgical devices and techniques; and help to identify patient subgroups that may benefit most from certain procedures. PMID:19266220

Variability of measured sonic boom signatures. Volume 2: Data report

NASA Technical Reports Server (NTRS)

Elmer, K. R.; Joshi, M. C.

1994-01-01

Sonic boom signatures from two databases, the BOOMFILE and the XB-70, were analyzed in terms of C-weighted sound exposure level (CSEL), A-weighted sound exposure level (ASEL), and Stevens Mark VII perceived level (PLdB), as well as the more traditional peak positive overpressure and rise time. The variability of these parameters due to propagation through atmosphere was analyzed for different aircraft Mach number and altitude groups. The low Mach number/low altitude group had significantly greater variation in rise time, overpressure, and loudness level than the high Mach number/high altitude group. The loudness of measured booms were found to have a variation of up to 25 dB relative to the loudness of boom predicted for a non-turbulent atmosphere. This is due primarily to the steeper ray paths of the high Mach number/high altitude group and the corresponding shorter distances traveled by these rays through the lower atmosphere resulting in reduced refraction effects. The general trend of decreased overpressure and loudness level with increasing lateral distance was also seen. Sonic boom signatures from early morning flights had less variation in rise time and overpressure than afternoon flights because of reduced turbulence. Measures of asymmetry (difference between compression and expansion portion of the signature) showed that the variability in Delta loudness level was greater than the variability in Delta overpressure due to the large influence of turbulence on rise time. Lastly, analysis of data within 50 percent of lateral cutoff showed that the mean value for overpressure and loudness level was independent of time of day but that the frequency with which it occurred was greater in the morning. This is a clear indicator of increased turbulence in the afternoon.

Aging has the opposite effect on cAMP and cGMP circadian variations in rat Leydig cells.

PubMed

Baburski, Aleksandar Z; Sokanovic, Srdjan J; Andric, Silvana A; Kostic, Tatjana S

2017-05-01

The Leydig cell physiology displays a circadian rhythm driven by a complex interaction of the reproductive axis hormones and circadian system. The final output of this regulatory process is circadian pattern of steroidogenic genes expression and testosterone production. Aging gradually decreases robustness of rhythmic testosterone secretion without change in pattern of LH secretion. Here, we analyzed effect of aging on circadian variation of cAMP and cGMP signaling in Leydig cells. Results showed opposite effect of aging on cAMP and cGMP daily variation. Reduced amplitude of cAMP circadian oscillation was probably associated with changed expression of genes involved in cAMP production (increased circadian pattern of Adcy7, Adcy9, Adcy10 and decreased Adcy3); cAMP degradation (increased Pde4a, decreased Pde8b, canceled rhythm of Pde4d, completely reversed circadian pattern of Pde7b and Pde8a); and circadian expression of protein kinase A subunits (Prkac/PRKAC and Prkar2a). Aging stimulates expression of genes responsible for cGMP production (Nos2, Gucy1a3 and Gucy1b3/GUCYB3) and degradation (Pde5a, Pde6a and Pde6h) but the overall net effect is elevation of cGMP circadian oscillations in Leydig cells. In addition, the expression of cGMP-dependent kinase, Prkg1/PRKG1 is up-regulated. It seems that aging potentiate cGMP- and reduce cAMP-signaling in Leydig cells. Since both signaling pathways affect testosterone production and clockwork in the cells, further insights into these signaling pathways will help to unravel disorders linked to the circadian timing system, aging and reproduction.

The case for restraint in spinal surgery: does quality management have a role to play?

PubMed

Deyo, Richard A; Mirza, Sohail K

2009-08-01

Most quality improvement efforts in surgery have focused on the technical quality of care provided, rather than whether the care was indicated, or could have been provided with a safer procedure. Because risk is inherent in any procedure, reducing the number of unnecessary operations is an important issue in patient safety. In the case of lumbar spine surgery, several lines of evidence suggest that, in at least some locations, there may be excessively high surgery rates. This evidence comes from international comparisons of surgical rates; study of small area variations within countries; increasing surgical rates in the absence of new indications; comparisons of surgical outcomes between geographic areas with high or low surgical rates; expert opinion; the preferences of well-informed patients; and increasing rates of repeat surgery. From a population perspective, reducing unnecessary surgery may have a greater impact on complication rates than improving the technical quality of surgery that is performed. Evidence suggests this may be true for coronary bypass surgery in the US and hysterectomy rates in Canada. Though similar studies have not been done for spine surgery, wide geographic variations in surgical rates suggest that this could be the case for spine surgery as well. We suggest that monitoring geographic variations in surgery rates may become an important aspect of quality improvement, and that rates of repeat surgery may bear special attention. Patient registries can help in this regard, if they are very complete and rigorously maintained. They can provide data on surgical rates; offer post-marketing surveillance for new surgical devices and techniques; and help to identify patient subgroups that may benefit most from certain procedures.

Population genetic dynamics of three-spined sticklebacks (Gasterosteus aculeatus) in anthropogenic altered habitats

PubMed Central

Scharsack, Joern P; Schweyen, Hannah; Schmidt, Alexander M; Dittmar, Janine; Reusch, Thorsten BH; Kurtz, Joachim

2012-01-01

In industrialized and/or agriculturally used landscapes, inhabiting species are exposed to a variety of anthropogenic changes in their environments. Genetic diversity may be reduced if populations encounter founder events, bottlenecks, or isolation. Conversely, genetic diversity may increase if populations adapt to changes in selective regimes in newly created habitats. With the present study, genetic variability of 918 sticklebacks from 43 samplings (21.3 ± 3.8 per sample) at 36 locations from cultivated landscapes in Northwest Germany was analyzed at nine neutral microsatellite loci. To test if differentiation is influenced by habitat alterations, sticklebacks were collected from ancient running waters and adjacent artificial stagnant waters, from brooks with salt water inflow of anthropogenic and natural origin and adjacent freshwater sites. Overall population structure was dominated by isolation by distance (IBD), which was significant across all populations, and analysis of molecular variance (AMOVA) revealed that 10.6% of the variation was explained by river catchment area. Populations in anthropogenic modified habitats deviated from the general IBD structure and in the AMOVA, grouping by habitat type running/stagnant water explained 4.9% of variation and 1.4% of the variation was explained by salt-/freshwater habitat. Sticklebacks in salt-polluted water systems seem to exhibit elevated migratory activity between fresh- and saltwater habitats, reducing IBD. In other situations, populations showed distinct signs of genetic isolation, which in some locations was attributed to mechanical migration barriers, but in others to potential anthropogenic induced bottleneck or founder effects. The present study shows that anthropogenic habitat alterations may have diverse effects on the population genetic structure of inhabiting species. Depending on the type of habitat change, increased genetic differentiation, diversification, or isolation are possible consequences. PMID:22833789

Population genetic dynamics of three-spined sticklebacks (Gasterosteus aculeatus) in anthropogenic altered habitats.

PubMed

Scharsack, Joern P; Schweyen, Hannah; Schmidt, Alexander M; Dittmar, Janine; Reusch, Thorsten Bh; Kurtz, Joachim

2012-06-01

In industrialized and/or agriculturally used landscapes, inhabiting species are exposed to a variety of anthropogenic changes in their environments. Genetic diversity may be reduced if populations encounter founder events, bottlenecks, or isolation. Conversely, genetic diversity may increase if populations adapt to changes in selective regimes in newly created habitats. With the present study, genetic variability of 918 sticklebacks from 43 samplings (21.3 ± 3.8 per sample) at 36 locations from cultivated landscapes in Northwest Germany was analyzed at nine neutral microsatellite loci. To test if differentiation is influenced by habitat alterations, sticklebacks were collected from ancient running waters and adjacent artificial stagnant waters, from brooks with salt water inflow of anthropogenic and natural origin and adjacent freshwater sites. Overall population structure was dominated by isolation by distance (IBD), which was significant across all populations, and analysis of molecular variance (AMOVA) revealed that 10.6% of the variation was explained by river catchment area. Populations in anthropogenic modified habitats deviated from the general IBD structure and in the AMOVA, grouping by habitat type running/stagnant water explained 4.9% of variation and 1.4% of the variation was explained by salt-/freshwater habitat. Sticklebacks in salt-polluted water systems seem to exhibit elevated migratory activity between fresh- and saltwater habitats, reducing IBD. In other situations, populations showed distinct signs of genetic isolation, which in some locations was attributed to mechanical migration barriers, but in others to potential anthropogenic induced bottleneck or founder effects. The present study shows that anthropogenic habitat alterations may have diverse effects on the population genetic structure of inhabiting species. Depending on the type of habitat change, increased genetic differentiation, diversification, or isolation are possible consequences.

Association Between Genetic Variation in FOXO3 and Reductions in Inflammation and Disease Activity in Inflammatory Polyarthritis

PubMed Central

Viatte, Sebastien; Lee, James C.; Fu, Bo; Espéli, Marion; Lunt, Mark; De Wolf, Jack N. E.; Wheeler, Lily; Reynolds, John A.; Castelino, Madhura; Symmons, Deborah P. M.; Lyons, Paul A.

2016-01-01

Objective Genetic variation in FOXO3 (tagged by rs12212067) has been associated with a milder course of rheumatoid arthritis (RA) and shown to limit monocyte‐driven inflammation through a transforming growth factor β1–dependent pathway. This genetic association, however, has not been consistently observed in other RA cohorts. We sought to clarify the contribution of FOXO3 to prognosis in RA by combining detailed analysis of nonradiographic disease severity measures with an in vivo model of arthritis. Methods Collagen‐induced arthritis, the most commonly used mouse model of RA, was used to assess how Foxo3 contributes to arthritis severity. Using clinical, serologic, and biochemical methods, the arthritis that developed in mice carrying a loss‐of‐function mutation in Foxo3 was compared with that which occurred in littermate controls. The association of rs12212067 with nonradiographic measures of RA severity, including the C‐reactive protein level, the swollen joint count, the tender joint count, the Disease Activity Score in 28 joints, and the Health Assessment Questionnaire score, were modeled longitudinally in a large prospective cohort of patients with early RA. Results Loss of Foxo3 function resulted in more severe arthritis in vivo (both clinically and histologically) and was associated with higher titers of anticollagen antibodies and interleukin‐6 in the blood. Similarly, rs12212067 (a single‐nucleotide polymorphism that increases FOXO3 transcription) was associated with reduced inflammation, both biochemically and clinically, and with lower RA activity scores. Conclusion Consistent with its known role in restraining inflammatory responses, FOXO3 limits the severity of in vivo arthritis and, through genetic variation that increases its transcription, is associated with reduced inflammation and disease activity in RA patients, effects that result in less radiographic damage. PMID:27214848

Global variation in the cost of increasing ecosystem carbon

NASA Astrophysics Data System (ADS)

Larjavaara, Markku; Kanninen, Markku; Gordillo, Harold; Koskinen, Joni; Kukkonen, Markus; Käyhkö, Niina; Larson, Anne M.; Wunder, Sven

2018-01-01

Slowing the reduction, or increasing the accumulation, of organic carbon stored in biomass and soils has been suggested as a potentially rapid and cost-effective method to reduce the rate of atmospheric carbon increase1. The costs of mitigating climate change by increasing ecosystem carbon relative to the baseline or business-as-usual scenario has been quantified in numerous studies, but results have been contradictory, as both methodological issues and substance differences cause variability2. Here we show, based on 77 standardized face-to-face interviews of local experts with the best possible knowledge of local land-use economics and sociopolitical context in ten landscapes around the globe, that the estimated cost of increasing ecosystem carbon varied vastly and was perceived to be 16-27 times cheaper in two Indonesian landscapes dominated by peatlands compared with the average of the eight other landscapes. Hence, if reducing emissions from deforestation and forest degradation (REDD+) and other land-use mitigation efforts are to be distributed evenly across forested countries, for example, for the sake of international equity, their overall effectiveness would be dramatically lower than for a cost-minimizing distribution.

Prospective-pricing strategies for hospital and departmental effectiveness: the administrator's response.

PubMed

Van Etten, P

1985-10-01

The approach of the New England Medical Center toward case management and increased productivity, and the role of the pharmacy within this system, are described by a chief hospital administrator. External pressures that caused the hospital to alter its management style included changes in reimbursement, hospital overuse, increased competition, and a surplus of physicians. Variations in medical practice that affected admission rates, length of stay, and use of ancillary services existed because clinical and financial data had not been integrated, so clinicians had no information on the economic consequences of their decisions. The solution offered to this problem was to decentralize resource-use decisions to increase clinician accountability. The goal of the case-management system is to reduce the cost of intermediate product (e.g., laboratory tests) use through increased productivity. The system provides pharmacy with a new power base if pharmacists can reduce overall costs by influencing prescribers to use cost-effective therapies. Pharmacy can increase its influence within the institution by forming new relationships with administrators, physicians, and nurses that broaden its impact on cost.

Variations in levels of care between nursing home patients in a public health care system

PubMed Central

2014-01-01

Background Within the setting of a public health service we analyse the distribution of resources between individuals in nursing homes funded by global budgets. Three questions are pursued. Firstly, whether there are systematic variations between nursing homes in the level of care given to patients. Secondly, whether such variations can be explained by nursing home characteristics. And thirdly, how individual need-related variables are associated with differences in the level of care given. Methods The study included 1204 residents in 35 nursing homes and extra care sheltered housing facilities. Direct time spent with patients was recorded. In average each patient received 14.8 hours direct care each week. Multilevel regression analysis is used to analyse the relationship between individual characteristics, nursing home characteristics and time spent with patients in nursing homes. The study setting is the city of Trondheim, with a population of approximately 180 000. Results There are large variations between nursing homes in the total amount of individual care given to patients. As much as 24 percent of the variation of individual care between patients could be explained by variation between nursing homes. Adjusting for structural nursing home characteristics did not substantially reduce the variation between nursing homes. As expected a negative association was found between individual care and case-mix, implying that at nursing home level a more resource demanding case-mix is compensated by lowering the average amount of care. At individual level ADL-disability is the strongest predictor for use of resources in nursing homes. For the average user one point increase in ADL-disability increases the use of resources with 27 percent. Conclusion In a financial reimbursement model for nursing homes with no adjustment for case-mix, the amount of care patients receive does not solely depend on the patients’ own needs, but also on the needs of all the other residents. PMID:24597468

Variations in levels of care between nursing home patients in a public health care system.

PubMed

Døhl, Øystein; Garåsen, Helge; Kalseth, Jorid; Magnussen, Jon

2014-03-05

Within the setting of a public health service we analyse the distribution of resources between individuals in nursing homes funded by global budgets. Three questions are pursued. Firstly, whether there are systematic variations between nursing homes in the level of care given to patients. Secondly, whether such variations can be explained by nursing home characteristics. And thirdly, how individual need-related variables are associated with differences in the level of care given. The study included 1204 residents in 35 nursing homes and extra care sheltered housing facilities. Direct time spent with patients was recorded. In average each patient received 14.8 hours direct care each week. Multilevel regression analysis is used to analyse the relationship between individual characteristics, nursing home characteristics and time spent with patients in nursing homes. The study setting is the city of Trondheim, with a population of approximately 180 000. There are large variations between nursing homes in the total amount of individual care given to patients. As much as 24 percent of the variation of individual care between patients could be explained by variation between nursing homes. Adjusting for structural nursing home characteristics did not substantially reduce the variation between nursing homes. As expected a negative association was found between individual care and case-mix, implying that at nursing home level a more resource demanding case-mix is compensated by lowering the average amount of care. At individual level ADL-disability is the strongest predictor for use of resources in nursing homes. For the average user one point increase in ADL-disability increases the use of resources with 27 percent. In a financial reimbursement model for nursing homes with no adjustment for case-mix, the amount of care patients receive does not solely depend on the patients' own needs, but also on the needs of all the other residents.

Weight-loss changes PPAR expression, reduces atherosclerosis and improves cardiovascular function in obese insulin-resistant mice

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

Verreth, Wim; Verhamme, Peter; Pelat, Michael

2003-09-01

Weight-loss in obese insulin-resistant, but not in insulin-sensitive, persons reduces CHD risk. It is not known to what extent changes in the adipose gene expression profile are important for reducing CHD risk. We studied the effect of diet restriction-induced weight-loss on gene expression in adipose tissue, atherosclerosis and cardiovascular function in mice with combined leptin and LDL-receptor deficiency. Obesity, hypertriglyceridemia and insulin-resistance are associated with hypertension, impaired left ventricle function and accelerated atherosclerosis in those mice. Diet restriction during 12 weeks caused a 45% weight-loss and changes in the gene expression in adipose tissue of PPARa and PPAR? and ofmore » key genes regulating glucose transport and insulin sensitivity, lipid metabolism, oxidative stress and inflammation, most of which are under the transcriptional control of PPARs. These changes were associated with increased insulin-sensitivity, decreased hypertriglyceridemia, reduced mean 24-hour blood pressure and heart rate, restored circadian variations of blood pressure and heart rate, increased ejection fraction, and reduced atherosclerosis. Thus, induction of PPARa and PPAR? in adipose tissue is a key mechanism for reducing atherosclerosis and improving cardiovascular function resulting from weight-loss. Our observations point to the critical role of PPARs in the pathogenesis of cardiovascular features of the metabolic syndrome.« less

Dual effects of the winter monsoon on haze-fog variations in eastern China

NASA Astrophysics Data System (ADS)

Liu, Qian; Sheng, Lifang; Cao, Ziqi; Diao, Yina; Wang, Wencai; Zhou, Yang

2017-06-01

Previous studies have revealed a negative correlation between the East Asian winter monsoon and wintertime haze-fog events in China. The winter monsoon reduces haze-fog by advecting away aerosol particles and supplying clean air through cold waves. However, it is found that the frequency of haze-fog events on subseasonal time scales displays no correlation with typical winter monsoon indices. The results show that the accumulating and maintaining effects of calm weather related to the Siberian High, which is also a part of the monsoon circulation system, are equally important for the development of haze-fog events during winter. Correlation analysis indicates that subseasonal variations in haze-fog are closely related to the intensity of the Siberian High (r = 0.49). The Siberian High may increase the occurrence of haze-fog events by reducing the near surface wind speed and enhancing the stratification stability. To quantify the contribution of these diverse effects of the winter monsoon on the variations in haze-fog events, we analyzed haze-fog events during periods of cold wave activity and calm weather separately and contrasted the relative contributions of these two effects on different time scales. On the subseasonal scale, the effect of the Siberian High was 2.0 times that of cold waves; on the interannual scale, the effect of cold waves was 2.4 times that of the Siberian High. This study reveals the dual effects of the East Asian winter monsoon on wintertime haze-fog variations in eastern China and provides a more comprehensive understanding of the relationship between the monsoon and haze-fog events.

Physical Fitness and Aortic Stiffness Explain the Reduced Cognitive Performance Associated with Increasing Age in Older People.

PubMed

Kennedy, Greg; Meyer, Denny; Hardman, Roy J; Macpherson, Helen; Scholey, Andrew B; Pipingas, Andrew

2018-01-01

Greater physical fitness is associated with reduced rates of cognitive decline in older people; however, the mechanisms by which this occurs are still unclear. One potential mechanism is aortic stiffness, with increased stiffness resulting in higher pulsatile pressures reaching the brain and possibly causing progressive micro-damage. There is limited evidence that those who regularly exercise may have lower aortic stiffness. To investigate whether greater fitness and lower aortic stiffness predict better cognitive performance in older people and, if so, whether aortic stiffness mediates the relationship between fitness and cognition. Residents of independent living facilities, aged 60-90, participated in the study (N = 102). Primary measures included a computerized cognitive assessment battery, pulse wave velocity analysis to measure aortic stiffness, and the Six-Minute Walk test to assess fitness. Based on hierarchical regression analyses, structural equation modelling was used to test the mediation hypothesis. Both fitness and aortic stiffness independently predicted Spatial Working Memory (SWM) performance, however no mediating relationship was found. Additionally, the derived structural equation model shows that, in conjunction with BMI and sex, fitness and aortic stiffness explain 33% of the overall variation in SWM, with age no longer directly predicting any variation. Greater fitness and lower aortic stiffness both independently predict better SWM in older people. The strong effect of age on cognitive performance is totally mediated by fitness and aortic stiffness. This suggests that addressing both physical fitness and aortic stiffness may be important to reduce the rate of age associated cognitive decline.

Crop Model Improvement Reduces the Uncertainty of the Response to Temperature of Multi-Model Ensembles

NASA Technical Reports Server (NTRS)

Maiorano, Andrea; Martre, Pierre; Asseng, Senthold; Ewert, Frank; Mueller, Christoph; Roetter, Reimund P.; Ruane, Alex C.; Semenov, Mikhail A.; Wallach, Daniel; Wang, Enli

2016-01-01

To improve climate change impact estimates and to quantify their uncertainty, multi-model ensembles (MMEs) have been suggested. Model improvements can improve the accuracy of simulations and reduce the uncertainty of climate change impact assessments. Furthermore, they can reduce the number of models needed in a MME. Herein, 15 wheat growth models of a larger MME were improved through re-parameterization and/or incorporating or modifying heat stress effects on phenology, leaf growth and senescence, biomass growth, and grain number and size using detailed field experimental data from the USDA Hot Serial Cereal experiment (calibration data set). Simulation results from before and after model improvement were then evaluated with independent field experiments from a CIMMYT worldwide field trial network (evaluation data set). Model improvements decreased the variation (10th to 90th model ensemble percentile range) of grain yields simulated by the MME on average by 39% in the calibration data set and by 26% in the independent evaluation data set for crops grown in mean seasonal temperatures greater than 24 C. MME mean squared error in simulating grain yield decreased by 37%. A reduction in MME uncertainty range by 27% increased MME prediction skills by 47%. Results suggest that the mean level of variation observed in field experiments and used as a benchmark can be reached with half the number of models in the MME. Improving crop models is therefore important to increase the certainty of model-based impact assessments and allow more practical, i.e. smaller MMEs to be used effectively.

Sublethal effects of catch-and-release fishing: measuring capture stress, fish impairment, and predation risk using a condition index

USGS Publications Warehouse

Campbell, Matthew D.; Patino, Reynaldo; Tolan, J.M.; Strauss, R.E.; Diamond, S.

2009-01-01

The sublethal effects of simulated capture of red snapper (Lutjanus campechanus) were analysed using physiological responses, condition indexing, and performance variables. Simulated catch-and-release fishing included combinations of depth of capture and thermocline exposure reflective of environmental conditions experienced in the Gulf of Mexico. Frequency of occurrence of barotrauma and lack of reflex response exhibited considerable individual variation. When combined into a single condition or impairment index, individual variation was reduced, and impairment showed significant increases as depth increased and with the addition of thermocline exposure. Performance variables, such as burst swimming speed (BSS) and simulated predator approach distance (AD), were also significantly different by depth. BSSs and predator ADs decreased with increasing depth, were lowest immediately after release, and were affected for up to 15 min, with longer recovery times required as depth increased. The impairment score developed was positively correlated with cortisol concentration and negatively correlated with both BSS and simulated predator AD. The impairment index proved to be an efficient method to estimate the overall impairment of red snapper in the laboratory simulations of capture and shows promise for use in field conditions, to estimate release mortality and vulnerability to predation.

The impact of rate reduction and increased loudness on fundamental frequency characteristics in dysarthria.

PubMed

Tjaden, Kris; Wilding, Greg

2011-01-01

This study examined the extent to which articulatory rate reduction and increased loudness were associated with adjustments in utterance-level measures of fundamental frequency (F(0)) variability for speakers with dysarthria and healthy controls that have been shown to impact on intelligibility in previously published studies. More generally, the current study sought to compare and contrast how a slower-than-normal rate and increased vocal loudness impact on a variety of utterance-level F(0) characteristics for speakers with dysarthria and healthy controls. Eleven speakers with Parkinson's disease, 15 speakers with multiple sclerosis, and 14 healthy control speakers were audio recorded while reading a passage in habitual, loud, and slow conditions. Magnitude production was used to elicit variations in rate and loudness. Acoustic measures of duration, intensity and F(0) were obtained. For all speaker groups, a slower-than-normal articulatory rate and increased vocal loudness had distinct effects on F(0) relative to the habitual condition, including a tendency for measures of F(0) variation to be greater in the loud condition and reduced in the slow condition. These results suggest implications for the treatment of dysarthria. Copyright © 2010 S. Karger AG, Basel.

The Impact of Rate Reduction and Increased Loudness on Fundamental Frequency Characteristics in Dysarthria

PubMed Central

Tjaden, Kris; Wilding, Greg

2011-01-01

Objective This study examined the extent to which articulatory rate reduction and increased loudness were associated with adjustments in utterance-level measures of fundamental frequency (F0) variability for speakers with dysarthria and healthy controls that have been shown to impact on intelligibility in previously published studies. More generally, the current study sought to compare and contrast how a slower-than-normal rate and increased vocal loudness impact on a variety of utterance-level F0 characteristics for speakers with dysarthria and healthy controls. Patients and Methods Eleven speakers with Parkinson's disease, 15 speakers with multiple sclerosis, and 14 healthy control speakers were audio recorded while reading a passage in habitual, loud, and slow conditions. Magnitude production was used to elicit variations in rate and loudness. Acoustic measures of duration, intensity and F0 were obtained. Results and Conclusions For all speaker groups, a slower-than-normal articulatory rate and increased vocal loudness had distinct effects on F0 relative to the habitual condition, including a tendency for measures of F0 variation to be greater in the loud condition and reduced in the slow condition. These results suggest implications for the treatment of dysarthria. PMID:20938199

Dealing with feeling: Specific emotion regulation skills predict responses to stress in psychosis.

PubMed

Lincoln, Tania M; Hartmann, Maike; Köther, Ulf; Moritz, Steffen

2015-08-15

Elevated negative affect is an established link between minor stressors and psychotic symptoms. Less clear is why people with psychosis fail to regulate distressing emotions effectively. This study tests whether subjective, psychophysiological and symptomatic responses to stress can be predicted by specific emotion regulation (ER) difficulties. Participants with psychotic disorders (n=35) and healthy controls (n=28) were assessed for ER-skills at baseline. They were then exposed to a noise versus no stressor on different days, during which self-reported stress responses, state paranoia and skin conductance levels (SCL) were assessed. Participants with psychosis showed a stronger increase in self-reported stress and SCL in response to the stressor than healthy controls. Stronger increases in self-reported stress were predicted by a reduced ability to be aware of and tolerate distressing emotions, whereas increases in SCL were predicted by a reduced ability to be aware of, tolerate, accept and modify them. Although paranoid symptoms were not significantly affected by the stressors, individual variation in paranoid responses was also predicted by a reduced ability to be aware of and tolerate emotions. Differences in stress responses in the samples were no longer significant after controlling for ER skills. Thus, interventions that improve ER-skills could reduce stress-sensitivity in psychosis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Laboratory studies of near-grazing impulsive sound propagating over rough water.

PubMed

Qin, Qin; Lukaschuk, Sergei; Attenborough, Keith

2008-08-01

Acoustic impulses due to an electrical spark source (main acoustic energy near 15 kHz) have been measured after propagating near to the water surface in a shallow container resting on a vibrating platform. Control of the platform vibration enabled control of water wave amplitudes. Analysis of the results reveals systematic variations in the received acoustic waveforms as the mean trough-to-crest water wave amplitude is increased up to 7 mm. The amplitudes of the peaks corresponding to specular reflections are reduced and the variability in the tails of the waveforms is increased.

Features of electromagnetic processes in electric gas turbine installations

NASA Astrophysics Data System (ADS)

Kislyakov, M. A.; Chernov, V. A.; Maksimkin, V. L.; Bozhin, Yu. M.

2017-12-01

Electric gas turbine aggregates are considered in terms of ensuring reliable operation of gas-dynamic bearings. A complex of unfavorable factors affecting this unit of the installation is described, including rotor unbalance, eccentricity, irregularity of armature field rotation, its amplitude variation during rotor rotation, etc. The studies have shown that it is possible to increase the efficiency of EGTA by increasing the number of armature winding phases (i.e. reducing electromagnetic torque ripples), amplifying the damping circuits on the rotor, as well as by introducing pulse-width modulation of currents in the phases and flexible feedbacks.

Natural Variation in the Thermotolerance of Neural Function and Behavior due to a cGMP-Dependent Protein Kinase

PubMed Central

Dawson-Scully, Ken; Armstrong, Gary A.B.; Kent, Clement; Robertson, R. Meldrum; Sokolowski, Marla B.

2007-01-01

Although it is acknowledged that genetic variation contributes to individual differences in thermotolerance, the specific genes and pathways involved and how they are modulated by the environment remain poorly understood. We link natural variation in the thermotolerance of neural function and behavior in Drosophila melanogaster to the foraging gene (for, which encodes a cGMP-dependent protein kinase (PKG)) as well as to its downstream target, protein phosphatase 2A (PP2A). Genetic and pharmacological manipulations revealed that reduced PKG (or PP2A) activity caused increased thermotolerance of synaptic transmission at the larval neuromuscular junction. Like synaptic transmission, feeding movements were preserved at higher temperatures in larvae with lower PKG levels. In a comparative assay, pharmacological manipulations altering thermotolerance in a central circuit of Locusta migratoria demonstrated conservation of this neuroprotective pathway. In this circuit, either the inhibition of PKG or PP2A induced robust thermotolerance of neural function. We suggest that PKG and therefore the polymorphism associated with the allelic variation in for may provide populations with natural variation in heat stress tolerance. for's function in behavior is conserved across most organisms, including ants, bees, nematodes, and mammals. PKG's role in thermotolerance may also apply to these and other species. Natural variation in thermotolerance arising from genes involved in the PKG pathway could impact the evolution of thermotolerance in natural populations. PMID:17712421

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

Sun, Yu-Han; Wang, Jun-Xian; Chen, Xiao-Yang

Quasars are variable on timescales from days to years in UV/optical and generally appear bluer while they brighten. The physics behind the variations in fluxes and colors remains unclear. Using Sloan Digital Sky Survey g- and r-band photometric monitoring data for quasars in Stripe 82, we find that although the flux variation amplitude increases with timescale, the color variability exhibits the opposite behavior. The color variability of quasars is prominent at timescales as short as ∼10 days, but gradually reduces toward timescales up to years. In other words, the variable emission at shorter timescales is bluer than that at longermore » timescales. This timescale dependence is clearly and consistently detected at all redshifts from z = 0 to 3.5; thus, it cannot be due to contamination to broadband photometry from emission lines that do not respond to fast continuum variations. The discovery directly rules out the possibility that simply attributes the color variability to contamination from a non-variable redder component such as the host galaxy. It cannot be interpreted as changes in global accretion rate either. The thermal accretion disk fluctuation model is favored in the sense that fluctuations in the inner, hotter region of the disk are responsible for short-term variations, while longer-term and stronger variations are expected from the larger and cooler disk region. An interesting implication is that one can use quasar variations at different timescales to probe disk emission at different radii.« less

Evaluation of semiarid grassland degradation in North China from multiple perspectives

NASA Astrophysics Data System (ADS)

Han, D.; Wang, G.; Xue, B. L.; Xu, X.

2017-12-01

There has been increasing interest in grassland ecosystem degradation resulting from intensive human activity and climate change, especially in arid and semiarid regions. Species composition, grassland desertification, and aboveground biomass (AGB) are used as indicators of grassland degradation in this study. We comprehensively analyzed variations in these three indicators in semiarid grassland in North China, on multiple time scales, based on MODIS products and field sampling datasets. Since 1984, species composition has become simpler and species indicative of grassland degradation, such as Potentilla acaulis and Artemisia frigida, have become dominant. These changes indicate that serious grassland degradation has occurred since 1984. Grassland degradation was also analyzed on shorter time scales. Analyses of interannual variations during 2005-2015 showed that desertification decreased and average AGB in the growth season increased over the study area, indicating that grassland was recovering. Analyses of spatial variations showed that the position of slightly desertified grassland shifted and formed a band in the west, where the lowest AGB in the growth season was recorded but tendency ratio of AGB increased from 2005 to 2015. Climatic factors had critical effects on grassland degradation, as identified by the three indicators on different time scales. The simpler species composition resulted from the increase in average temperature and decrease in average precipitation over the past 30 years. For nearly a decade, an increase in precipitation and decreases in temperature and potential evapotranspiration reduced desertification and increased AGB in the growth season overall. Consequently, there has distinct difference in grassland degradation between analysis results on above two time scales, indicating multiple perspectives should be considered to accurately assess the state and characteristics of grassland degradation.

Music as therapy.

PubMed

Kemper, Kathi J; Danhauer, Suzanne C

2005-03-01

Music is widely used to enhance well-being, reduce stress, and distract patients from unpleasant symptoms. Although there are wide variations in individual preferences, music appears to exert direct physiologic effects through the autonomic nervous system. It also has indirect effects by modifying caregiver behavior. Music effectively reduces anxiety and improves mood for medical and surgical patients, for patients in intensive care units and patients undergoing procedures, and for children as well as adults. Music is a low-cost intervention that often reduces surgical, procedural, acute, and chronic pain. Music also improves the quality of life for patients receiving palliative care, enhancing a sense of comfort and relaxation. Providing music to caregivers may be a cost-effective and enjoyable strategy to improve empathy, compassion, and relationship-centered care while not increasing errors or interfering with technical aspects of care.

Aligning US health and immigration policy to reduce the incidence of tuberculosis.

PubMed

Blewett, L A; Marmor, S; Pintor, J K; Boudreaux, M

2014-04-01

Tuberculosis (TB) is a significant public health issue, claiming 1.4 million lives worldwide in 2011. Using data from the 2009-2010 National Health Interview Survey, we examine variation in 'having heard of TB' (HTB) by global region of birth and health insurance status. Cross-sectional analysis with bivariate comparisons and multivariate logistic regression to evaluate how adults differed in reported HTB, controlling for global region of birth. HTB rates ranged from 63.4% of adults born in Asia to 88.6% born in Europe. Uninsured immigrants had the lowest rate of HTB, ranging from a low of 50.1% of uninsured adults born in Asia to 77.6% born in Europe and 90.8% of US-born uninsured adults. Longer length of time in the United States (>5 years) was significantly associated with increased likelihood of HTB, as did being of Asian race/ethnicity and being male. Those with private health insurance coverage had the highest rates of HTB. To reduce persistent TB, public health program directors and policy makers must 1) recognize the variation in HTB by global region of birth and prioritize areas with the lowest HTB rates, and 2) reduce barriers to health insurance coverage by eliminating the 5-year ban for public program coverage for new immigrants.

PERCEIVED DISCRIMINATION AND PSYCHOLOGICAL WELL-BEING: THE MEDIATING AND MODERATING ROLE OF SENSE OF CONTROL*

PubMed Central

Jang, Yuri; Chiriboga, David A.; Small, Brent J.

2010-01-01

Being discriminated against is an unpleasant and stressful experience, and its connection to reduced psychological well-being is well-documented. The present study hypothesized that a sense of control would serve as both mediator and moderator in the dynamics of perceived discrimination and psychological well-being. In addition, variations by age, gender, and race in the effects of perceived discrimination were explored. Data from the Midlife Development in the United States (MIDUS) survey (N = 1,554; age range = 45 to 74) provided supportive evidence for the hypotheses. The relationships between perceived discrimination and positive and negative affect were reduced when sense of control was controlled, demonstrating the role of sense of control as a mediator. The moderating role of sense of control was also supported, but only in the analysis for negative affect: the combination of a discriminatory experience and low sense of control markedly increased negative affect. In addition, age and gender variations were observed: the negative impact of perceived discrimination on psychological well-being was more pronounced among younger adults and females compared to their counterparts. The findings elucidated the mechanisms by which perceived discrimination manifested its psychological outcomes, and suggest ways to reduce adverse consequences associated with discriminatory experiences. PMID:18459602

Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors.

PubMed

Villa-Gomez, D K; Cassidy, J; Keesman, K J; Sampaio, R; Lens, P N L

2014-03-01

Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4(2-) ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing bioreactors. The sulfide was measured using a sulfide ion selective electrode (pS) and the values obtained were used to calculate proportional-integral-derivative (PID) controller parameters. The experiments were performed in an inverse fluidized bed bioreactor with automated operation using the LabVIEW software version 2009(®). A rapid response and high sulfide increment was obtained through a stepwise increase in the CODin concentration, while a stepwise decrease to the HRT exhibited a slower response with smaller sulfide increment. Irrespective of the way the OLR was decreased, the pS response showed a time-varying behavior due to sulfide accumulation (HRT change) or utilization of substrate sources that were not accounted for (CODin change). The pS electrode response, however, showed to be informative for applications in sulfate reducing bioreactors. Nevertheless, the recorded pS values need to be corrected for pH variations and high sulfide concentrations (>200 mg/L). Copyright © 2013 Elsevier Ltd. All rights reserved.

Polymorphism at the defensin gene in the Anopheles gambiae complex: testing different selection hypotheses

PubMed Central

Simard, Frédéric; Licht, Monica; Besansky, Nora J.; Lehmann, Tovi

2007-01-01

Genetic variation in defensin, a gene encoding a major effector molecule of insects immune response was analyzed within and between populations of three members of the Anopheles gambiae complex. The species selected included the two anthropophilic species, An. gambiae and An. arabiensis and the most zoophilic species of the complex, An. quadriannulatus. The first species was represented by four populations spanning its extreme genetic and geographical ranges, whereas each of the other two species was represented by a single population. We found (i) reduced overall polymorphism in the mature peptide region and in the total coding region, together with specific reductions in rare and moderately frequent mutations (sites) in the coding region compared with non coding regions, (ii) markedly reduced rate of nonsynonymous diversity compared with synonymous variation in the mature peptide and virtually identical mature peptide across the three species, and (iii) increased divergence between species in the mature peptide together with reduced differentiation between populations of An. gambiae in the same DNA region. These patterns suggest a strong purifying selection on the mature peptide and probably the whole coding region. Because An. quadriannulatus is not exposed to human pathogens, identical mature peptide and similar pattern of polymorphism across species implies that human pathogens played no role as selective agents on this peptide. PMID:17161659

Perceived discrimination and psychological well-being: the mediating and moderating role of sense of control.

PubMed

Jang, Yuri; Chiriboga, David A; Small, Brent J

2008-01-01

Being discriminated against is an unpleasant and stressful experience, and its connection to reduced psychological well-being is well-documented. The present study hypothesized that a sense of control would serve as both mediator and moderator in the dynamics of perceived discrimination and psychological well-being. In addition, variations by age, gender, and race in the effects of perceived discrimination were explored. Data from the Midlife Development in the United States (MIDUS) survey (N=1554; age range = 45 to 74) provided supportive evidence for the hypotheses. The relationships between perceived discrimination and positive and negative affect were reduced when sense of control was controlled, demonstrating the role of sense of control as a mediator. The moderating role of sense of control was also supported, but only in the analysis for negative affect: the combination of a discriminatory experience and low sense of control markedly increased negative affect. In addition, age and gender variations were observed: the negative impact of perceived discrimination on psychological well-being was more pronounced among younger adults and females compared to their counterparts. The findings elucidated the mechanisms by which perceived discrimination manifested its psychological outcomes, and suggest ways to reduce adverse consequences associated with discriminatory experiences.

Discovering Condition-Specific Gene Co-Expression Patterns Using Gaussian Mixture Models: A Cancer Case Study.

PubMed

Ficklin, Stephen P; Dunwoodie, Leland J; Poehlman, William L; Watson, Christopher; Roche, Kimberly E; Feltus, F Alex

2017-08-17

A gene co-expression network (GCN) describes associations between genes and points to genetic coordination of biochemical pathways. However, genetic correlations in a GCN are only detectable if they are present in the sampled conditions. With the increasing quantity of gene expression samples available in public repositories, there is greater potential for discovery of genetic correlations from a variety of biologically interesting conditions. However, even if gene correlations are present, their discovery can be masked by noise. Noise is introduced from natural variation (intrinsic and extrinsic), systematic variation (caused by sample measurement protocols and instruments), and algorithmic and statistical variation created by selection of data processing tools. A variety of published studies, approaches and methods attempt to address each of these contributions of variation to reduce noise. Here we describe an approach using Gaussian Mixture Models (GMMs) to address natural extrinsic (condition-specific) variation during network construction from mixed input conditions. To demonstrate utility, we build and analyze a condition-annotated GCN from a compendium of 2,016 mixed gene expression data sets from five tumor subtypes obtained from The Cancer Genome Atlas. Our results show that GMMs help discover tumor subtype specific gene co-expression patterns (modules) that are significantly enriched for clinical attributes.

Effects of Genetic Drift and Gene Flow on the Selective Maintenance of Genetic Variation

PubMed Central

Star, Bastiaan; Spencer, Hamish G.

2013-01-01

Explanations for the genetic variation ubiquitous in natural populations are often classified by the population–genetic processes they emphasize: natural selection or mutation and genetic drift. Here we investigate models that incorporate all three processes in a spatially structured population, using what we call a construction approach, simulating finite populations under selection that are bombarded with a steady stream of novel mutations. As expected, the amount of genetic variation compared to previous models that ignored the stochastic effects of drift was reduced, especially for smaller populations and when spatial structure was most profound. By contrast, however, for higher levels of gene flow and larger population sizes, the amount of genetic variation found after many generations was greater than that in simulations without drift. This increased amount of genetic variation is due to the introduction of slightly deleterious alleles by genetic drift and this process is more efficient when migration load is higher. The incorporation of genetic drift also selects for fitness sets that exhibit allele-frequency equilibria with larger domains of attraction: they are “more stable.” Moreover, the finiteness of populations strongly influences levels of local adaptation, selection strength, and the proportion of allele-frequency vectors that can be distinguished from the neutral expectation. PMID:23457235

Study on Interaction Between Diurnal Tide and Atmospheric Aerosols Observed by Mars Climate Sounder

NASA Astrophysics Data System (ADS)

Wu, Z.; Li, T.

2016-12-01

The increased local time coverage observed by Mars Climate Sounder (MCS) on board Mars Reconnaissance Orbiter (MRO) can enable direct extraction of thermal tides in Mars middle atmosphere with reduced aliasing. Using temperature profiles from Mars year (MY) 30 to 32, we study the latitudinal and seasonal variations of tides and stationary planetary waves with zonal wave numbers s = 1-3. The amplitude of the migrating diurnal tide (DW1) has strong semiannual variations both in the equatorial region and in the Southern Hemisphere (SH) middle latitudes. Aerosols widely distributed in the atmosphere of Mars, namely, dust and water ice also show apparent diurnal variations, which may be caused by a dynamical process of tidal vertical wind. Tidal response in dust abundance indicates an annual variation with maximum amplitude in aphelion seasons while the background abundance of dust peaks in perihelion seasons when global dust storm occurs frequently, which suggests that extremely large abundance of dust may restrain its own tidal response. Water ice abundance in the middle latitudes has a semiannual variation which is similar to the thermal diurnal tide. In addition, the diurnal heating rate of aerosols is calculated and Hough decomposition is performed to estimate the radiative effect of aerosols on diurnal tide.

Food and fitness: associations between crop yields and life-history traits in a longitudinally monitored pre-industrial human population.

PubMed

Hayward, Adam D; Holopainen, Jari; Pettay, Jenni E; Lummaa, Virpi

2012-10-22

Severe food shortage is associated with increased mortality and reduced reproductive success in contemporary and historical human populations. Studies of wild animal populations have shown that subtle variation in environmental conditions can influence patterns of mortality, fecundity and natural selection, but the fitness implications of such subtle variation on human populations are unclear. Here, we use longitudinal data on local grain production, births, marriages and mortality so as to assess the impact of crop yield variation on individual age-specific mortality and fecundity in two pre-industrial Finnish populations. Although crop yields and fitness traits showed profound year-to-year variation across the 70-year study period, associations between crop yields and mortality or fecundity were generally weak. However, post-reproductive individuals of both sexes, and individuals of lower socio-economic status experienced higher mortality when crop yields were low. This is the first longitudinal, individual-based study of the associations between environmental variation and fitness traits in pre-industrial humans, which emphasizes the importance of a portfolio of mechanisms for coping with low food availability in such populations. The results are consistent with evolutionary ecological predictions that natural selection for resilience to food shortage is likely to weaken with age and be most severe on those with the fewest resources.

Reducing lumber thickness variation using real-time statistical process control

Treesearch

Thomas M. Young; Brian H. Bond; Jan Wiedenbeck

2002-01-01

A technology feasibility study for reducing lumber thickness variation was conducted from April 2001 until March 2002 at two sawmills located in the southern U.S. A real-time statistical process control (SPC) system was developed that featured Wonderware human machine interface technology (HMI) with distributed real-time control charts for all sawing centers and...

Annual variations in the Martian bow shock location as observed by the Mars Express mission

NASA Astrophysics Data System (ADS)

Hall, B. E. S.; Lester, M.; Sánchez-Cano, B.; Nichols, J. D.; Andrews, D. J.; Edberg, N. J. T.; Opgenoorth, H. J.; Fränz, M.; Holmström, M.; Ramstad, R.; Witasse, O.; Cartacci, M.; Cicchetti, A.; Noschese, R.; Orosei, R.

2016-11-01

The Martian bow shock distance has previously been shown to be anticorrelated with solar wind dynamic pressure but correlated with solar extreme ultraviolet (EUV) irradiance. Since both of these solar parameters reduce with the square of the distance from the Sun, and Mars' orbit about the Sun increases by ˜0.3 AU from perihelion to aphelion, it is not clear how the bow shock location will respond to variations in these solar parameters, if at all, throughout its orbit. In order to characterize such a response, we use more than 5 Martian years of Mars Express Analyser of Space Plasma and EneRgetic Atoms (ASPERA-3) Electron Spectrometer measurements to automatically identify 11,861 bow shock crossings. We have discovered that the bow shock distance as a function of solar longitude has a minimum of 2.39RM around aphelion and proceeds to a maximum of 2.65RM around perihelion, presenting an overall variation of ˜11% throughout the Martian orbit. We have verified previous findings that the bow shock in southern hemisphere is on average located farther away from Mars than in the northern hemisphere. However, this hemispherical asymmetry is small (total distance variation of ˜2.4%), and the same annual variations occur irrespective of the hemisphere. We have identified that the bow shock location is more sensitive to variations in the solar EUV irradiance than to solar wind dynamic pressure variations. We have proposed possible interaction mechanisms between the solar EUV flux and Martian plasma environment that could explain this annual variation in bow shock location.

Seasonal Variation in Penicillin Use in Mexico and Brazil: Analysis of the Impact of Over-the-Counter Restrictions

PubMed Central

Santa-Ana-Tellez, Yared; Mantel-Teeuwisse, Aukje K.; Leufkens, Hubert G. M.

2014-01-01

During 2010, Mexico and Brazil implemented policies to enforce existing laws of restricting over-the-counter sales of antibiotics. We determined if the enforcement led to more appropriate antibiotic use by measuring changes in seasonal variation of penicillin use. We used retail quarterly sales data in defined daily doses per 1,000 inhabitant-days (DDD/TID) from IMS Health from the private sector in Mexico and Brazil from the first quarter of 2007 to the first quarter of 2013. This database contains information on volume of antibiotics sold in retail pharmacies using information from wholesalers. We used interrupted time-series models controlling for external factors with the use of antihypertensives with interaction terms to assess changes in trend, level, and variation in use between quarters for total penicillin use and by active substance. The most used penicillin was amoxicillin, followed by amoxicillin-clavulanic acid and ampicillin (minimal use in Brazil). Before the restrictions, the seasonal variation in penicillin use was 1.1 DDD/TID in Mexico and 0.8 DDD/TID in Brazil. In Mexico, we estimated a significant decrease in the seasonal variation of 0.4 DDD/TID after the restriction, mainly due to changes in seasonal variation of amoxicillin and ampicillin. In Brazil, the seasonal variation did not change significantly, overall and in the breakdown by individual active substances. For Mexico, inappropriate penicillin use may have diminished after the restrictions were enforced. For Brazil, increasing use and no change in seasonal variation suggest that further efforts are needed to reduce inappropriate penicillin use. PMID:25313222

Reducing shingle waste at a manufacturing facility: 1990 MNTAP summer intern report

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

Menke, D.

1990-12-31

CertainTeed manufactures roofing shingles at it`s Shakopee, MN facility. Two process coating lines, and one assembly line, produce fifteen shingle types in fifteen different colors. The wastes generated by this process were the result of planned and unplanned variations in the continuous production process. Planned variations included changes in color, while felt breaks were common unplanned variations. Five options were identified that could reduce the amount of waste generated: Using a standard procedure for recovering from felt breaks, Creating a process cushion to maintain continuous production in the event of temporary shutdowns, An automated color change process, Manufacture of amore » new product from waste material, Minor process changes to reduce the frequency of breaks.« less

An Integrated Approach for RNA-seq Data Normalization.

PubMed

Yang, Shengping; Mercante, Donald E; Zhang, Kun; Fang, Zhide

2016-01-01

DNA copy number alteration is common in many cancers. Studies have shown that insertion or deletion of DNA sequences can directly alter gene expression, and significant correlation exists between DNA copy number and gene expression. Data normalization is a critical step in the analysis of gene expression generated by RNA-seq technology. Successful normalization reduces/removes unwanted nonbiological variations in the data, while keeping meaningful information intact. However, as far as we know, no attempt has been made to adjust for the variation due to DNA copy number changes in RNA-seq data normalization. In this article, we propose an integrated approach for RNA-seq data normalization. Comparisons show that the proposed normalization can improve power for downstream differentially expressed gene detection and generate more biologically meaningful results in gene profiling. In addition, our findings show that due to the effects of copy number changes, some housekeeping genes are not always suitable internal controls for studying gene expression. Using information from DNA copy number, integrated approach is successful in reducing noises due to both biological and nonbiological causes in RNA-seq data, thus increasing the accuracy of gene profiling.

Unusual dynamics of extinction in a simple ecological model.

PubMed Central

Sinha, S; Parthasarathy, S

1996-01-01

Studies on natural populations and harvesting biological resources have led to the view, commonly held, that (i) populations exhibiting chaotic oscillations run a high risk of extinction; and (ii) a decrease in emigration/exploitation may reduce the risk of extinction. Here we describe a simple ecological model with emigration/depletion that shows behavior in contrast to this. This model displays unusual dynamics of extinction and survival, where populations growing beyond a critical rate can persist within a band of high depletion rates, whereas extinction occurs for lower depletion rates. Though prior to extinction at lower depletion rates the population exhibits chaotic dynamics with large amplitudes of variation and very low minima, at higher depletion rates the population persists at chaos but with reduced variation and increased minima. For still higher values, within the band of persistence, the dynamics show period reversal leading to stability. These results illustrate that chaos does not necessarily lead to population extinction. In addition, the persistence of populations at high depletion rates has important implications in the considerations of strategies for the management of biological resources. PMID:8643661

The impact of a parkinsonian lesion on dynamic striatal dopamine transmission depends on nicotinic receptor activation

PubMed Central

Jennings, Katie A.; Platt, Nicola J.; Cragg, Stephanie J.

2015-01-01

Dopamine function is disturbed in Parkinson's disease (PD), but whether and how release of dopamine from surviving neurons is altered has long been debated. Nicotinic acetylcholine receptors (nAChRs) on dopamine axons powerfully govern dopamine release and could be critical contributing factors. We revisited whether fundamental properties of dopamine transmission are changed in a parkinsonian brain and tested the potentially profound masking effects of nAChRs. Using real-time detection of dopamine in mouse striatum after a partial 6-hydroxydopamine lesion and under nAChR inhibition, we reveal that dopamine signals show diminished sensitivity to presynaptic activity. This effect manifested as diminished contrast between DA release evoked by the lowest versus highest frequencies. This reduced activity-dependence was underpinned by loss of short-term facilitation of dopamine release, consistent with an increase in release probability (Pr). With nAChRs active, the reduced activity-dependence of dopamine release after a parkinsonian lesion was masked. Consequently, moment-by-moment variation in activity of nAChRs may lead to dynamic co-variation in dopamine signal impairments in PD. PMID:26117304

Microbiological characteristics of multi-media PRB reactor in the bioremediation of groundwater contaminated by petroleum hydrocarbons.

PubMed

Liu, Hong; Zhang, Lanying; Deng, Haijing; Liu, Na; Liu, Cuizhu

2011-10-01

A multi-media bio-PRB reactor was designed to treat groundwater contaminated with petroleum hydrocarbons. After a 208-day bioremediation, combined with the total petroleum hydrocarbons content in the groundwater flowed through the reactor, microbiological characteristics of the PRB reactor including microbes immobilized and its dehydrogenase activity were investigated. TPH was significantly reduced by as much as 65% in the back of the second media layer, whereas in the third layer, the TPH content reached lower than 1 mg l⁻¹. For microbes immobilized on the media, the variations with depth in different media were significantly the same and the regularity was obvious in the forepart of the media, which increased with depth at first and then reduced gradually, while in the back-end, the microbes almost did not have any variations with depth but decreased with the distance. The dehydrogenase activity varied from 2.98 to 16.16 mg TF L⁻¹ h⁻¹ and its distribution illustrated a similar trend with numbers of microbial cell, therefore, the noticeable correlation was found between them.

Farallon de Medinilla seabird and Tinian moorhen analyses

USGS Publications Warehouse

Camp, Richard J.; Leopold, Christina R.; Brinck, Kevin W.; Juola, Franz

2015-01-01

This report assesses the trends in brown booby (Sula leucogaster), masked booby (S. dactylatra), and red-footed booby (S. sula) counts collected on Farallon de Medinilla and Mariana common moorhen (Gallinula chloropus guami) counts on Tinian, Commonwealth of the Northern Mariana Islands to help elucidate patterns in bird numbers. During either monthly or quarterly surveys between 1997 and 2014 counts of all four bird species were recorded, generating a relatively noisy time series revealing inter-annual variation in index counts by as much as 1,000%. For the purposes of assessing long-term population trends across years we chose a single, species-specific month to assess trends. Doing so reduces the effect of intra-annual variation allowing the analysis to focus on inter-annual variation important to long-term trends assessment. There are clear fluctuations in the counts of all four species. Although the trends were non-significant, there is some evidence that masked and red-footed booby species have declined while brown booby and moorhen have increased.

Accelerating an Ordered-Subset Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction with a Power Factor and Total Variation Minimization.

PubMed

Huang, Hsuan-Ming; Hsiao, Ing-Tsung

2016-01-01

In recent years, there has been increased interest in low-dose X-ray cone beam computed tomography (CBCT) in many fields, including dentistry, guided radiotherapy and small animal imaging. Despite reducing the radiation dose, low-dose CBCT has not gained widespread acceptance in routine clinical practice. In addition to performing more evaluation studies, developing a fast and high-quality reconstruction algorithm is required. In this work, we propose an iterative reconstruction method that accelerates ordered-subsets (OS) reconstruction using a power factor. Furthermore, we combine it with the total-variation (TV) minimization method. Both simulation and phantom studies were conducted to evaluate the performance of the proposed method. Results show that the proposed method can accelerate conventional OS methods, greatly increase the convergence speed in early iterations. Moreover, applying the TV minimization to the power acceleration scheme can further improve the image quality while preserving the fast convergence rate.

Experimental Study of Hydroxy Gas (HHO) Production with Variation in Current, Voltage and Electrolyte Concentration

NASA Astrophysics Data System (ADS)

Alam, Noor; Pandey, K. M.

2017-08-01

In this paper, work has been carried out experimentally for the investigation of the effects of variation incurrent, voltage, temperature, chemical concentration and reaction time on the amount of hydroxy gas produced. Further effects on the overall electrolysis efficiency of advance alkaline water is also studied. The hydroxy gas (HHO) has been produced experimentally by the electrolysis of alkaline water with parallel plate electrode of 316L-grade stainless steel. The electrode has been selected on the basis of corrosion resistance and inertness with respect to electrolyte (KOH). The process used for the production of HHO is conventional as compared to the other production processes because of reduced energy consumption, less maintenance and low setup cost. From the experimental results, it has been observed that with increase in voltage, temperature and electrolyte concentration of alkaline solution, the production of hydroxy gas has increased about 30 to 40% with reduction in electrical energy consumption.

Differences in muscle load between computer and non-computer work among office workers.

PubMed

Richter, J M; Mathiassen, S E; Slijper, H P; Over, E A B; Frens, M A

2009-12-01

Introduction of more non-computer tasks has been suggested to increase exposure variation and thus reduce musculoskeletal complaints (MSC) in computer-intensive office work. This study investigated whether muscle activity did, indeed, differ between computer and non-computer activities. Whole-day logs of input device use in 30 office workers were used to identify computer and non-computer work, using a range of classification thresholds (non-computer thresholds (NCTs)). Exposure during these activities was assessed by bilateral electromyography recordings from the upper trapezius and lower arm. Contrasts in muscle activity between computer and non-computer work were distinct but small, even at the individualised, optimal NCT. Using an average group-based NCT resulted in less contrast, even in smaller subgroups defined by job function or MSC. Thus, computer activity logs should be used cautiously as proxies of biomechanical exposure. Conventional non-computer tasks may have a limited potential to increase variation in muscle activity during computer-intensive office work.

Systematic control of optical features in aluminosilicate glass waveguides using direct femtosecond laser writing

NASA Astrophysics Data System (ADS)

Babu, B. Hari; Niu, Mengsi; Yang, Xiaoyu; Wang, Yanbo; Feng, Lin; Qin, Wei; Hao, Xiao-Tao

2017-10-01

Low loss optical waveguides inside aluminosilicate glasses have been successfully fabricated using direct femtosecond laser writing. To establish the influence of pulse energy and host variations on the optical waveguides have been tentatively explored and systematically studied with the help of different spectroscopic techniques. Isochronal annealing treatment effectively reduces the insertion losses to 1.01 ± 0.28 dB at 632.8 nm. A red shift of the Raman band has been observed with increasing Al2O3 content due to the bond angle variations. The point defects such as non-bridging oxygen hole centers have been corroborated by the photoluminescence studies and significant red-shift has also been documented with increasing Al2O3 content. In addition, there is no NBOHC defects perceived after isochronal annealing treatment inside the glass waveguides. Our results envisage that the present glass waveguides should be promising and potential for applications in passive waveguides and integrated photonic devices.

Process for hydrocracking carbonaceous material to provide fuels or chemical feed stock

DOEpatents

Duncan, Dennis A.

1980-01-01

A process is disclosed for hydrocracking coal or other carbonaceous material to produce various aromatic hydrocarbons including benzene, toluene, xylene, ethylbenzene, phenol and cresols in variable relative concentrations while maintaining a near constant maximum temperature. Variations in relative aromatic concentrations are achieved by changing the kinetic severity of the hydrocracking reaction by altering the temperature profile up to and quenching from the final hydrocracking temperature. The relative concentration of benzene to the alkyl and hydroxyl aromatics is increased by imposing increased kinetic severity above that corresponding to constant heating rate followed by immediate quenching at about the same rate to below the temperature at which dehydroxylation and dealkylation reactions appreciably occur. Similarly phenols, cresols and xylenes are produced in enhanced concentrations by adjusting the temperature profile to provide a reduced kinetic severity relative to that employed when high benzene concentrations are desired. These variations in concentrations can be used to produce desired materials for chemical feed stocks or for fuels.

Advanced complex trait analysis.

PubMed

Gray, A; Stewart, I; Tenesa, A

2012-12-01

The Genome-wide Complex Trait Analysis (GCTA) software package can quantify the contribution of genetic variation to phenotypic variation for complex traits. However, as those datasets of interest continue to increase in size, GCTA becomes increasingly computationally prohibitive. We present an adapted version, Advanced Complex Trait Analysis (ACTA), demonstrating dramatically improved performance. We restructure the genetic relationship matrix (GRM) estimation phase of the code and introduce the highly optimized parallel Basic Linear Algebra Subprograms (BLAS) library combined with manual parallelization and optimization. We introduce the Linear Algebra PACKage (LAPACK) library into the restricted maximum likelihood (REML) analysis stage. For a test case with 8999 individuals and 279,435 single nucleotide polymorphisms (SNPs), we reduce the total runtime, using a compute node with two multi-core Intel Nehalem CPUs, from ∼17 h to ∼11 min. The source code is fully available under the GNU Public License, along with Linux binaries. For more information see http://www.epcc.ed.ac.uk/software-products/acta. a.gray@ed.ac.uk Supplementary data are available at Bioinformatics online.

Accelerating an Ordered-Subset Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction with a Power Factor and Total Variation Minimization

PubMed Central

Huang, Hsuan-Ming; Hsiao, Ing-Tsung

2016-01-01

In recent years, there has been increased interest in low-dose X-ray cone beam computed tomography (CBCT) in many fields, including dentistry, guided radiotherapy and small animal imaging. Despite reducing the radiation dose, low-dose CBCT has not gained widespread acceptance in routine clinical practice. In addition to performing more evaluation studies, developing a fast and high-quality reconstruction algorithm is required. In this work, we propose an iterative reconstruction method that accelerates ordered-subsets (OS) reconstruction using a power factor. Furthermore, we combine it with the total-variation (TV) minimization method. Both simulation and phantom studies were conducted to evaluate the performance of the proposed method. Results show that the proposed method can accelerate conventional OS methods, greatly increase the convergence speed in early iterations. Moreover, applying the TV minimization to the power acceleration scheme can further improve the image quality while preserving the fast convergence rate. PMID:27073853

Silencing is noisy: population and cell level noise in telomere-adjacent genes is dependent on telomere position and sir2.

PubMed

Anderson, Matthew Z; Gerstein, Aleeza C; Wigen, Lauren; Baller, Joshua A; Berman, Judith

2014-07-01

Cell-to-cell gene expression noise is thought to be an important mechanism for generating phenotypic diversity. Furthermore, telomeric regions are major sites for gene amplification, which is thought to drive genetic diversity. Here we found that individual subtelomeric TLO genes exhibit increased variation in transcript and protein levels at both the cell-to-cell level as well as at the population-level. The cell-to-cell variation, termed Telomere-Adjacent Gene Expression Noise (TAGEN) was largely intrinsic noise and was dependent upon genome position: noise was reduced when a TLO gene was expressed at an ectopic internal locus and noise was elevated when a non-telomeric gene was expressed at a telomere-adjacent locus. This position-dependent TAGEN also was dependent on Sir2p, an NAD+-dependent histone deacetylase. Finally, we found that telomere silencing and TAGEN are tightly linked and regulated in cis: selection for either silencing or activation of a TLO-adjacent URA3 gene resulted in reduced noise at the neighboring TLO but not at other TLO genes. This provides experimental support to computational predictions that the ability to shift between silent and active chromatin states has a major effect on cell-to-cell noise. Furthermore, it demonstrates that these shifts affect the degree of expression variation at each telomere individually.

The role of sexual selection and conflict in mediating among-population variation in mating strategies and sexually dimorphic traits in Sepsis punctum.

PubMed

Dmitriew, Caitlin; Blanckenhorn, Wolf U

2012-01-01

The black scavenger fly Sepsis punctum exhibits striking among-population variation in the direction and magnitude of sexual size dimorphism, modification to the male forelimb and pre-copulatory behaviour. In some populations, male-biased sexual size dimorphism is observed; in other, less dimorphic, populations males court prior to mating. Such variation in reproductive traits is of interest to evolutionary biologists because it has the potential to limit gene flow among populations, contributing to speciation. Here, we investigate whether large male body size and modified forefemur are associated with higher male mating success within populations, whether these traits are associated with higher mating success among populations, and if these traits carry viability costs that could constrain their response to sexual selection. Flies from five distinct populations were reared at high or low food, generating high and low quality males. The expression of body size, forelimb morphology and courtship rate were each greater at high food, but high food males experienced higher mating success or reduced latency to first copulation in only one of the populations. Among populations, overall mating success increased with the degree of male-bias in overall body size and forelimb modification, suggesting that these traits have evolved as a means of increasing male mating rate. The increased mating success observed in large-male populations raises the question of why variation in magnitude of dimorphism persists among populations. One reason may be that costs of producing a large size constrain the evolution of ever-larger males. We found no evidence that juvenile mortality under food stress was greater for large-male populations, but development time was considerably longer and may represent an important constraint in an ephemeral and competitive growth environment.

Recent Trends in the Arctic Navigable Ice Season and Links to Atmospheric Circulation

NASA Astrophysics Data System (ADS)

Maslanik, J.; Drobot, S.

2002-12-01

One of the potential effects of Arctic climate warming is an increase in the navigable ice season, perhaps resulting in development of the Arctic as a major shipping route. The distance from western North American ports to Europe through the Northwest Passage (NWP) or the Northern Sea Route (NSR) is typically 20 to 60 percent shorter than travel through the Panama Canal, while travel between Europe and the Far East may be reduced by as much as three weeks compared to transport through the Suez Canal. An increase in the navigable ice season would also improve commercial opportunities within the Arctic region, such as mineral and oil exploration and tourism, which could potentially expand the economic base of Arctic residents and companies, but which would also have negative environmental impacts. Utilizing daily passive-microwave derived sea ice concentrations, trends and variability in the Arctic navigable ice season are examined from 1979 through 2001. Trend analyses suggest large increases in the length of the navigable ice season in the Kara and Barents seas, the Sea of Okhotsk, and the Beaufort Sea, with decreases in the length of the navigable ice season in the Bering Sea. Interannual variations in the navigable ice season largely are governed by fluctuations in low-frequency atmospheric circulation, although the specific annular modes affecting the length of the navigable ice season vary by region. In the Beaufort and East Siberian seas, variations in the North Atlantic Oscillation/Arctic Oscillation control the navigable ice season, while variations in the East Pacific anomaly play an important role in controlling the navigable ice season in the Kara and Barents seas. In Hudson Bay, the Canadian Arctic Archipelago, and Baffin Bay, interannual variations in the navigable ice season are strongly related to the Pacific Decadal Oscillation.

Joint effects of pleiotropic selection and stabilizing selection on the maintenance of quantitative genetic variation at mutation-selection balance.

PubMed Central

Zhang, Xu-Sheng; Hill, William G

2002-01-01

In quantitative genetics, there are two basic "conflicting" observations: abundant polygenic variation and strong stabilizing selection that should rapidly deplete that variation. This conflict, although having attracted much theoretical attention, still stands open. Two classes of model have been proposed: real stabilizing selection directly on the metric trait under study and apparent stabilizing selection caused solely by the deleterious pleiotropic side effects of mutations on fitness. Here these models are combined and the total stabilizing selection observed is assumed to derive simultaneously through these two different mechanisms. Mutations have effects on a metric trait and on fitness, and both effects vary continuously. The genetic variance (V(G)) and the observed strength of total stabilizing selection (V(s,t)) are analyzed with a rare-alleles model. Both kinds of selection reduce V(G) but their roles in depleting it are not independent: The magnitude of pleiotropic selection depends on real stabilizing selection and such dependence is subject to the shape of the distributions of mutational effects. The genetic variation maintained thus depends on the kurtosis as well as the variance of mutational effects: All else being equal, V(G) increases with increasing leptokurtosis of mutational effects on fitness, while for a given distribution of mutational effects on fitness, V(G) decreases with increasing leptokurtosis of mutational effects on the trait. The V(G) and V(s,t) are determined primarily by real stabilizing selection while pleiotropic effects, which can be large, have only a limited impact. This finding provides some promise that a high heritability can be explained under strong total stabilizing selection for what are regarded as typical values of mutation and selection parameters. PMID:12242254

Forest productivity varies with soil moisture more than temperature in a small montane watershed

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

Wei, Liang; Zhou, Hang; Link, Timothy E

Mountainous terrain creates variability in microclimate, including nocturnal cold air drainage and resultant temperature inversions. Driven by the elevational temperature gradient, vapor pressure deficit (VPD) also varies with elevation. Soil depth and moisture availability often increase from ridgetop to valley bottom. These variations complicate predictions of forest productivity and other biological responses. We analyzed spatiotemporal air temperature (T) and VPD variations in a forested, 27-km 2 catchment that varied from 1000 to 1650 m in elevation. Temperature inversions occurred on 76% of mornings in the growing season. The inversion had a clear upper boundary at midslope (~1370 m a.s.l.). Vapormore » pressure was relatively constant across elevations, therefore VPD was mainly controlled by T in the watershed. Here, we assessed the impact of microclimate and soil moisture on tree height, forest productivity, and carbon stable isotopes (δ 13C) using a physiological forest growth model (3-PG). Simulated productivity and tree height were tested against observations derived from lidar data. The effects on photosynthetic gas-exchange of dramatic elevational variations in T and VPD largely cancelled as higher temperature (increasing productivity) accompanies higher VPD (reducing productivity). Although it was not measured, the simulations suggested that realistic elevational variations in soil moisture predicted the observed decline in productivity with elevation. Therefore, in this watershed, the model parameterization should have emphasized soil moisture rather than precise descriptions of temperature inversions.« less

Control your inventory in a world of lean retailing.

PubMed

Abernathy, F H; Dunlop, J T; Hammond, J H; Weil, D

2000-01-01

As retailers adopt lean retailing practices, manufacturers are feeling the pinch. Retailers no longer place large seasonal orders for goods in advance-instead, they require ongoing replenishment of stock, forcing manufacturers to predict demand and then hold substantial inventories indefinitely. Manufacturers now carry the cost of inventory risk--the possibility that demand will dry up and goods will have to be sold below cost. And as product proliferation increases, customer demand becomes harder to predict. Most manufacturers apply one inventory policy for all stock-keeping units in a product line. But the inventory demand for SKUs within the same product line can vary significantly. SKUs with high volume typically have little variation in weekly sales, while slow-selling SKUs can vary enormously in weekly sales. The greater the variation, the larger the inventory the manufacturer must hold relative to an SKU's expected weekly sales. By differentiating inventory policies at the SKU level, manufacturers can reduce inventories for the high-volume SKUs and increase them for the low-volume ones--and thereby improve the profit-ability of the entire line. SKU-level differentiation can also be applied to sourcing strategies. Instead of producing all the SKUs for a product line at a single location, either offshore at low cost or close to market at higher cost, manufacturers can typically do better by going for a mixed allocation. Low-variation goods should be produced mainly offshore, while high-variation goods are best made close to markets.

Baseline Levels and Trimestral Variation of Triiodothyronine and Thyroxine and Their Association with Mortality in Maintenance Hemodialysis Patients

PubMed Central

Meuwese, Christiaan L.; Dekker, Friedo W.; Lindholm, Bengt; Qureshi, Abdul R.; Heimburger, Olof; Barany, Peter; Stenvinkel, Peter; Carrero, Juan J.

2012-01-01

Summary Background and objectives Conflicting evidence exists with regard to the association of thyroid hormones and mortality in dialysis patients. This study assesses the association between basal and trimestral variation of thyroid stimulating hormone, triiodothyronine, and thyroxine and mortality. Design, setting, participants, & measurements In 210 prevalent hemodialysis patients, serum triiodothyronine, thyroxine, thyroid stimulating hormone, and interleukin-6 were measured 3 months apart. Cardiovascular and non-cardiovascular deaths were registered during follow-up. Based on fluctuations along tertiles of distribution, four trimestral patterns were defined for each thyroid hormone: persistently low, decrease, increase, and persistently high. The association of baseline levels and trimestral variation with mortality was investigated with Kaplan–Meier curves and Cox proportional hazard models. Results During follow-up, 103 deaths occurred. Thyroid stimulating hormone levels did not associate with mortality. Patients with relatively low basal triiodothyronine concentrations had higher hazards of dying than patients with high levels. Longitudinally, patients with persistently low levels of triiodothyronine during the 3-month period had higher mortality hazards than those having persistently high levels. These associations were mainly attributable to cardiovascular-related mortality. The association between thyroxine and mortality was not altered after adjustment for triiodothyronine. Conclusions Hemodialysis patients with reduced triiodothyronine or thyroxine levels bear an increased mortality risk, especially due to cardiovascular causes. This was true when considering both baseline measurements and trimestral variation patterns. Our longitudinal design adds observational evidence supporting the hypothesis that the link may underlie a causal effect. PMID:22246282

Baseline levels and trimestral variation of triiodothyronine and thyroxine and their association with mortality in maintenance hemodialysis patients.

PubMed

Meuwese, Christiaan L; Dekker, Friedo W; Lindholm, Bengt; Qureshi, Abdul R; Heimburger, Olof; Barany, Peter; Stenvinkel, Peter; Carrero, Juan J

2012-01-01

Conflicting evidence exists with regard to the association of thyroid hormones and mortality in dialysis patients. This study assesses the association between basal and trimestral variation of thyroid stimulating hormone, triiodothyronine, and thyroxine and mortality. In 210 prevalent hemodialysis patients, serum triiodothyronine, thyroxine, thyroid stimulating hormone, and interleukin-6 were measured 3 months apart. Cardiovascular and non-cardiovascular deaths were registered during follow-up. Based on fluctuations along tertiles of distribution, four trimestral patterns were defined for each thyroid hormone: persistently low, decrease, increase, and persistently high. The association of baseline levels and trimestral variation with mortality was investigated with Kaplan-Meier curves and Cox proportional hazard models. During follow-up, 103 deaths occurred. Thyroid stimulating hormone levels did not associate with mortality. Patients with relatively low basal triiodothyronine concentrations had higher hazards of dying than patients with high levels. Longitudinally, patients with persistently low levels of triiodothyronine during the 3-month period had higher mortality hazards than those having persistently high levels. These associations were mainly attributable to cardiovascular-related mortality. The association between thyroxine and mortality was not altered after adjustment for triiodothyronine. Hemodialysis patients with reduced triiodothyronine or thyroxine levels bear an increased mortality risk, especially due to cardiovascular causes. This was true when considering both baseline measurements and trimestral variation patterns. Our longitudinal design adds observational evidence supporting the hypothesis that the link may underlie a causal effect.

Forest productivity varies with soil moisture more than temperature in a small montane watershed

DOE PAGES

Wei, Liang; Zhou, Hang; Link, Timothy E; ...

2018-05-16

Mountainous terrain creates variability in microclimate, including nocturnal cold air drainage and resultant temperature inversions. Driven by the elevational temperature gradient, vapor pressure deficit (VPD) also varies with elevation. Soil depth and moisture availability often increase from ridgetop to valley bottom. These variations complicate predictions of forest productivity and other biological responses. We analyzed spatiotemporal air temperature (T) and VPD variations in a forested, 27-km 2 catchment that varied from 1000 to 1650 m in elevation. Temperature inversions occurred on 76% of mornings in the growing season. The inversion had a clear upper boundary at midslope (~1370 m a.s.l.). Vapormore » pressure was relatively constant across elevations, therefore VPD was mainly controlled by T in the watershed. Here, we assessed the impact of microclimate and soil moisture on tree height, forest productivity, and carbon stable isotopes (δ 13C) using a physiological forest growth model (3-PG). Simulated productivity and tree height were tested against observations derived from lidar data. The effects on photosynthetic gas-exchange of dramatic elevational variations in T and VPD largely cancelled as higher temperature (increasing productivity) accompanies higher VPD (reducing productivity). Although it was not measured, the simulations suggested that realistic elevational variations in soil moisture predicted the observed decline in productivity with elevation. Therefore, in this watershed, the model parameterization should have emphasized soil moisture rather than precise descriptions of temperature inversions.« less

Hyperglycemia-conditioned increase in alpha-2-macroglobulin in healthy normal subjects: a phenomenon correlated with deficient antithrombin III activity.

PubMed

Ceriello, A; Quatraro, A; Dello Russo, P; Marchi, E; Barbanti, M; Giugliano, D

1989-01-01

Induced hyperglycemia in normal subjects increases alpha 2-macroglobulin (alpha 2M) activity and alpha 2M concentration and reduces antithrombin III (ATIII) activity, while it does not affect ATIII plasma concentration. Hyperglycemia-determined variations in ATIII activity and alpha 2M molecules are correlated in an inverse and parallel fashion. A compensatory role for the increase in alpha 2M in the regulation of the coagulation system may be hypothesized. Moreover, these data provide evidence that hyperglycemia may decrease, directly, the biological function of some proteins and may influence the levels of some risk factors for the development of complications in diabetes.

Determination of the N2 recombination rate coefficient in the ionosphere

NASA Technical Reports Server (NTRS)

Orsini, N.; Torr, D. G.; Brinton, H. C.; Brace, L. H.; Hanson, W. B.; Hoffman, J. H.; Nier, A. O.

1977-01-01

Measurements of aeronomic parameters made by the Atmosphere Explorer-C satellite are used to determine the recombination rate coefficient of N2(+) in the ionosphere. The rate is found to increase significantly with decreasing electron density. Values obtained range from approximately 1.4 x 10 to the -7th to 3.8 x 10 to the -7th cu cm/sec. This variation is explained in a preliminary way in terms of an increase in the rate coefficient with vibrational excitation. Thus, high electron densities depopulate high vibrational levels reducing the effective recombination rate, whereas, low electron densities result in an enhancement in the population of high vibrational levels, thus, increasing the effective recombination rate.

Metabolite changes in nine different soybean varieties grown under field and greenhouse conditions.

PubMed

Maria John, K M; Natarajan, Savithiry; Luthria, Devanand L

2016-11-15

Global food security remains a worldwide concern due to changing climate, increasing population, and reduced agriculture acreages. Greenhouse cultivation increases productivity by extending growing seasons, reducing pest infestations and providing protection against short term drastic weather fluctuations like frost, heat, rain, and wind. In the present study, we examined and compared the metabolic responses of nine soybean varieties grown under field and greenhouse conditions. Extracts were assayed by GC-FID, GC-MS, and LC-MS for the identification of 10 primary (amino acids, organic acids, and sugars) and 10 secondary (isoflavones, fatty acid methyl esters) metabolites. Sugar molecules (glucose, sucrose, and pinitol) and isoflavone aglycons were increased but the isoflavones glucoside content decreased in the greenhouse cultivated soybeans. The amino acids and organic acids varied between the varieties. The results show that clustering (PCA and PLS-DA) patterns of soybean metabolites were significantly influenced by the genetic variation and growing conditions. Published by Elsevier Ltd.

Changes in precipitation recycling over arid regions in the Northern Hemisphere

NASA Astrophysics Data System (ADS)

Li, Ruolin; Wang, Chenghai; Wu, Di

2018-01-01

Changes of precipitation recycling (PR) in Northern Hemisphere from 1981 to 2010 are investigated using a water recycling model. The temporal and spatial characteristics of recycling in arid regions are analyzed. The results show that the regional precipitation recycling ratio (PRR) in arid regions is larger than in wet regions. PRR in arid regions has obvious seasonal variation, ranging from more than 25 % to less than 1 %. Furthermore, in arid regions, PRR is significantly negatively correlated with precipitation (correlation coefficient r = -0.5, exceeding the 99 % significance level). Moreover, the trend of PRR is related to changes in precipitation in two ways. PRR decreases with increasing precipitation in North Africa, which implies that less locally evaporated vapor converts into actual precipitation. However, in Asian arid regions, the PRR increases as precipitation reduces, which implies that more locally evaporated vapor converts into rainfall. Further, as PRR mainly depends on evapotranspiration, the PRR trend in Asian arid regions develops as temperature increases and more evaporated vapor enters the atmosphere to offset the reduced rainfall.

Gun bore flaw image matching based on improved SIFT descriptor

NASA Astrophysics Data System (ADS)

Zeng, Luan; Xiong, Wei; Zhai, You

2013-01-01

In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor

CD11b activation suppresses TLR-dependent inflammation and autoimmunity in systemic lupus erythematosus

PubMed Central

Faridi, Mohd Hafeez; Khan, Samia Q.; Zhao, Wenpu; Lee, Ha Won; Altintas, Mehmet M.; Zhang, Kun; Kumar, Vinay; Armstrong, Andrew R.; Carmona-Rivera, Carmelo; Dorschner, Jessica M.; Schnaith, Abigail M.; Li, Xiaobo; Ghodke-Puranik, Yogita; Moore, Erica; Irizarry-Caro, Jorge; Zhang, Tingting; Day, Rachael; Stoub, Darren; Hoffmann, Victoria; Khaliqdina, Shehryar Jehangir; Bhargava, Prachal; Santander, Ana M.; Torroella-Kouri, Marta; Issac, Biju; Cimbaluk, David J.; Zloza, Andrew; Prabhakar, Rajeev; Deep, Shashank; Jolly, Meenakshi; Koh, Kwi Hye; Reichner, Jonathan S.; Bradshaw, Elizabeth M.; Chen, JianFeng; Moita, Luis F.; Yuen, Peter S.; Li Tsai, Wanxia; Singh, Bhupinder; Reiser, Jochen; Nath, Swapan K.; Niewold, Timothy B.; Vazquez-Padron, Roberto I.

2017-01-01

Genetic variations in the ITGAM gene (encoding CD11b) strongly associate with risk for systemic lupus erythematosus (SLE). Here we have shown that 3 nonsynonymous ITGAM variants that produce defective CD11b associate with elevated levels of type I interferon (IFN-I) in lupus, suggesting a direct link between reduced CD11b activity and the chronically increased inflammatory status in patients. Treatment with the small-molecule CD11b agonist LA1 led to partial integrin activation, reduced IFN-I responses in WT but not CD11b-deficient mice, and protected lupus-prone MRL/Lpr mice from end-organ injury. CD11b activation reduced TLR-dependent proinflammatory signaling in leukocytes and suppressed IFN-I signaling via an AKT/FOXO3/IFN regulatory factor 3/7 pathway. TLR-stimulated macrophages from CD11B SNP carriers showed increased basal expression of IFN regulatory factor 7 (IRF7) and IFN-β, as well as increased nuclear exclusion of FOXO3, which was suppressed by LA1-dependent activation of CD11b. This suggests that pharmacologic activation of CD11b could be a potential mechanism for developing SLE therapeutics. PMID:28263189

Current issues in dietary acrylamide: formation, mitigation and risk assessment.

PubMed

Pedreschi, Franco; Mariotti, María Salomé; Granby, Kit

2014-01-15

Acrylamide (AA) is known as a neurotoxin in humans and it is classified as a probable human carcinogen by the International Agency of Research on Cancer. AA is produced as by-product of the Maillard reaction in starchy foods processed at high temperatures (>120 °C). This review includes the investigation of AA precursors, mechanisms of AA formation and AA mitigation technologies in potato, cereal and coffee products. Additionally, most relevant issues of AA risk assessment are discussed. New technologies tested from laboratory to industrial scale face, as a major challenge, the reduction of AA content of browned food, while still maintaining its attractive organoleptic properties. Reducing sugars such as glucose and fructose are the major contributors to AA in potato-based products. On the other hand, the limiting substrate of AA formation in cereals and coffee is the free amino acid asparagine. For some products the addition of glycine or asparaginase reduces AA formation during baking. Since, for potatoes, the limiting substrate is reducing sugars, increases in sugar content in potatoes during storage then introduce some difficulties and potentially quite large variations in the AA content of the final product. Sugars in potatoes may be reduced by blanching. Levels of AA in different foods show large variations and no general upper limit is easily applicable, since some formation will always occur. Current policy is that practical measures should be taken voluntarily to reduce AA formation in vulnerable foods since AA is considered a health risk at the concentrations found in foods. © 2013 Society of Chemical Industry.

Increased Hydrologic Connectivity: Consequences of Reduced Water Storage Capacity in the Delmarva Peninsula (U.S.)

NASA Astrophysics Data System (ADS)

Mclaughlin, D. L.; Jones, C. N.; Evenson, G. R.; Golden, H. E.; Lane, C.; Alexander, L. C.; Lang, M.

2017-12-01

Combined geospatial and modeling approaches are required to fully enumerate wetland hydrologic connectivity and downstream effects. Here, we utilized both geospatial analysis and hydrologic modeling to explore drivers and consequences of modified surface water connectivity in the Delmarva Peninsula, with particular focus on increased connectivity via pervasive wetland ditching. Our geospatial analysis quantified both historical and contemporary wetland storage capacity across the region, and suggests that over 70% of historical storage capacity has been lost due to this ditching. Building upon this analysis, we applied a catchment-scale model to simulate implications of reduced storage capacity on catchment-scale hydrology. In short, increased connectivity (and concomitantly reduced wetland water storage capacity) decreases catchment inundation extent and spatial heterogeneity, shortens cumulative residence times, and increases downstream flow variation with evident effects on peak and baseflow dynamics. As such, alterations in connectivity have implications for hydrologically mediated functions in catchments (e.g., nutrient removal) and downstream systems (e.g., maintenance of flow for aquatic habitat). Our work elucidates such consequences in Delmarva Peninsula while also providing new tools for broad application to target wetland restoration and conservation. Views expressed are those of the authors and do not necessarily reflect policies of the US EPA or US FWS.

Twin studies reveal specific imbalances in the mucosa-associated microbiota of patients with ileal Crohn's disease

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

Willing, B.; Halfvarson, J.; Dicksved, J.

2008-08-15

Large inter-individual variation in the composition of the intestinal microbiota between unrelated individuals has made it challenging to identify specific aspects of dysbiosis that lead to Crohn's disease. To reduce variations in exposure during establishment of the gut flora and influence of genotype, we studied the mucosaassociated microbiota of monozygotic twin pairs that were discordant (n=6) or concordant (n=4) for Crohn's disease. DNA was extracted from biopsies collected from 5 locations between the ileum and rectum. Bacterial 16S ribosomal RNA genes were amplified and community composition assessed by terminal-restriction fragment length polymorphism, cloning and sequencing and quantitative real-time PCR. Themore » microbial compositions at all biopsy locations for each individual were similar, regardless of disease state, but there were differences between individuals. In particular, individuals with predominantly ileal Crohn's had a dramatically lower abundance (P<0.001) of Faecalibacterium prausnitzii and increased abundance (P<0.03) of Escherichia coli compared to healthy co-twins and those with Crohn's localized in the colon. This dysbiosis was significantly correlated to the disease phenotype rather than genotype. The reduced abundance of F. prausnitzii and increased abundance of E. coli are indicative of an ileal Crohn's disease phenotype, distinct from colonic Crohn's disease and the relative abundances of these specific bacterial populations are promising biomarker candidates for differential diagnosis of Crohn's and eventually customized treatment.« less

Influence of riparian and watershed alterations on sandbars in a Great Plains river

USGS Publications Warehouse

Fischer, Jeffrey M.; Paukert, Craig P.; Daniels, M.L.

2014-01-01

Anthropogenic alterations have caused sandbar habitats in rivers and the biota dependent on them to decline. Restoring large river sandbars may be needed as these habitats are important components of river ecosystems and provide essential habitat to terrestrial and aquatic organisms. We quantified factors within the riparian zone of the Kansas River, USA, and within its tributaries that influenced sandbar size and density using aerial photographs and land use/land cover (LULC) data. We developed, a priori, 16 linear regression models focused on LULC at the local, adjacent upstream river bend, and the segment (18–44 km upstream) scales and used an information theoretic approach to determine what alterations best predicted the size and density of sandbars. Variation in sandbar density was best explained by the LULC within contributing tributaries at the segment scale, which indicated reduced sandbar density with increased forest cover within tributary watersheds. Similarly, LULC within contributing tributary watersheds at the segment scale best explained variation in sandbar size. These models indicated that sandbar size increased with agriculture and forest and decreased with urban cover within tributary watersheds. Our findings suggest that sediment supply and delivery from upstream tributary watersheds may be influential on sandbars within the Kansas River and that preserving natural grassland and reducing woody encroachment within tributary watersheds in Great Plains rivers may help improve sediment delivery to help restore natural river function.

Influence of the thermodynamic parameters on the temper embrittlement of SA508 Gr.4N Ni-Cr-Mo low alloy steel with variation of Ni, Cr and Mn contents

NASA Astrophysics Data System (ADS)

Park, Sang-Gyu; Lee, Ki-Hyoung; Min, Ki-Deuk; Kim, Min-Chul; Lee, Bong-Sang

2012-07-01

It is well known that SA508 Gr.4N low alloy steel offers improved fracture toughness and strength compared to commercial low alloy steels such as SA508 Gr.3 Mn-Mo-Ni low alloy steel. In this study, the effects of Cr, Mn, and Ni on temper embrittlement in SA508 Gr.4N low alloy steel were evaluated from the viewpoint of thermodynamic parameters such as P diffusivity and C activity. The changes of the ductile-brittle transition temperatures before and after aging were correlated with varying alloying element content, and the diffusivity of P and the activity of C were calculated and correlated with the transition behaviors. The addition of Ni, Cr, and Mn reduce the resistance to temper embrittlement, showing increased Transition-Temperature Shift (TTS) and an increased fraction of intergranular fracture. Although the diffusivity of P is changed by the addition of alloying elements, it does not considerably affect the temper embrittlement. The Mn and Cr content in the matrix significantly reduce the C activity, with showing an inversely proportional relationship to TTS. The change of susceptibility to temper embrittlement caused by Cr and Mn addition could be explained by the variation of C activity. Unlike Cr and Mn, Ni has little effect on the temper embrittlement and C activity.

Improvement of Diurnal Blood Pressure Variation by Azilsartan

PubMed Central

Okamura, Keisuke; Shirai, Kazuyuki; Okuda, Tetsu; Urata, Hidenori

2018-01-01

Background Azilsartan is an angiotensin II receptor blocker with a potent antihypertensive effect. Methods In a multicenter, prospective, open-label study, 265 patients with poor blood pressure control despite treatment with other angiotensin II receptor blockers were switched to 20 mg/day of azilsartan (patients on standard dosages) or 40 mg/day of azilsartan (patients on high dosages). Results Blood pressure was 149/83 mm Hg before switching and was significantly reduced from 1 month after switching until final assessment (132/76 mm Hg, P < 0.001). The pulse rate was 72/min before switching and increased significantly from 3 months after switching until final assessment (74/min, P < 0.005). A significant decrease of home morning systolic and diastolic pressure was observed from 1 and 3 months, respectively. Home morning blood pressure was 143/82 mm Hg before switching and 130/76 mm Hg at final assessment (P < 0.01). The morning-evening difference of systolic blood pressure decreased from 14.6 to 6.6 mm Hg after switching (P = 0.09). The estimated glomerular filtration rate was significantly decreased at 3, 6, and 12 months after switching, and serum uric acid was significantly increased at 12 months. No serious adverse events occurred. Conclusion Azilsartan significantly reduced the blood pressure and decreased diurnal variation in patients responding poorly to other angiotensin II receptor blockers. PMID:29238433

Anatomical variation of mesophyll conductance under potassium deficiency has a vital role in determining leaf photosynthesis.

PubMed

Lu, Zhifeng; Lu, Jianwei; Pan, Yonghui; Lu, Piaopiao; Li, Xiaokun; Cong, Rihuan; Ren, Tao

2016-11-01

Leaves exposed to potassium (K) deficiency usually present decreased mesophyll conductance (g m ) and photosynthesis (A). The relative contributions of leaf anatomical traits in determining g m have been quantified; however, anatomical variabilities related to low g m under K starvation remain imperfectly known. A one-dimensional model was used to quantify anatomical controls of the entire CO 2 diffusion pathway resistance within a leaf on two Brassica napus L. cultivars in response to K deficiency. Leaf photosynthesis of both cultivars was significantly decreased under K deficiency in parallel with down-regulated g m . The mesophyll conductance limitation contributed to more than one-half of A decline. The decreased internal air space in K-starved leaves was associated with the increase of gas-phase resistance. Potassium deficiency reduced liquid-phase conductance by decreasing the exposed surface area of chloroplasts per unit leaf area (S c /S), and enlarging the resistance of the cytoplasm that can be interpreted by the increasing distance of chloroplast from cell wall, and between adjacent chloroplasts. Additionally, the discrepancies of A between two cultivars were in part because of g m variations, ascribing to an altered S c /S. These results emphasize the important role of K on the regulation of g m by enhancing S c /S and reducing cytoplasm resistance. © 2016 John Wiley & Sons Ltd.

Lead-acid battery research and development—a vital key to winning new business

NASA Astrophysics Data System (ADS)

Bullock, Kathryn R.

Battery strings are operated in a partial-state-of-charge mode (PSoC) in several new and changing applications for lead-acid batteries, in which the battery is seldom, if ever, fully charged or discharged. The lead battery industry faces new challenges as additional failure modes become evident in these PSoC applications. Without overcharge, cell imbalances caused by variations in cell temperature will cause premature failures. Valve-regulated lead-acid batteries are especially susceptible because of the heat generated by oxygen recombination at the negative plate. Improved thermal properties are shown by a proprietary battery design that combines absorptive glass mat and gelled acid technologies. Well-designed power systems are also required to reduce cell-to-cell temperature variations and, thereby, increase battery life.

Quality indicators in inflammatory bowel disease.

PubMed

Berry, Sameer K; Melmed, Gil Y

2018-01-01

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is a chronic, debilitating, and expensive condition affecting millions of people globally. There is significant variation in the quality of care for patients with IBD across North America, Europe, and Asia; this variation suggests poor quality of care due to overuse, underuse, or misuse of health services and disparity of outcomes. Several initiatives have been developed to reduce variation in care delivery and improve processes of care, patient outcomes, and reduced healthcare costs. These initiatives include the development of quality indicator sets to standardize care across organizations, and learning health systems to enable data sharing between doctors and patients, and sharing of best practices among providers. These programs have been variably successful in improving patient outcomes and reducing healthcare utilization. Further studies are needed to demonstrate the long-term impact and applicability of these efforts in different geographic areas around the world, as regional variations in patient populations, societal preferences, and costs should inform local quality improvement efforts.

Hypoosmotic stress in the mussel Perna perna (Linnaeus, 1758): Is ecological history a determinant for organismal responses?

NASA Astrophysics Data System (ADS)

Rola, Regina Coimbra; Souza, Marta Marques; Sandrini, Juliana Zomer

2017-04-01

Ecological history of organisms may be related to different responses and adaptations to stressors. This study aims to evaluate whether marine brown mussels (Perna perna Linnaeus, 1758) collected from sites with distinct histories of fluctuations in abiotic parameters, including salinity, respond differently to hypoosmotic stress. Mussels were collected at different sites (a marine site, with no history of salinity variation, and an estuarine site, with usual salinity variations) and exposed in laboratory for 14 days to hypoosmotic stress (salinities 25 and 20). It was observed that mussels collected at the marine site showed increased oxygen consumption (VO2), reduced haemolymph osmolality and concentrations of Na+, Cl-, and K+; increased levels of ninhydrin-positive substances in the haemolymph, and no changes in gill Na+/K+-ATPase activity, as expected for osmoconforming organisms. For animals collected at the estuarine site, except for VO2, this same pattern was only observed on day 1 of hypoosmotic stress. Unexpectedly, on days 4 and 14, VO2 decreased, the osmolality and ionic concentration returned to near baseline values, and mussels gill Na+/K+-ATPase activity increased at day 4. This long-term response detected for estuarine mussels is similar to that observed for osmoregulating organisms, which is very unexpected for marine bivalves. Despite being novel in the relevant literature, these results suggest that in some situations mussels could adopt osmoregulating behavior, such as increasing Na+/K+-ATPase activity and thereby probably reducing water circulating inside valves. In conclusion, these results indicate that ecological history, shown here by differences in organismal origin, influence physiological parameters of mussels in response to a stressful situation.

Controlled environment life support system: Calcium-related leaf injuries on plants

NASA Technical Reports Server (NTRS)

Tibbitts, T. W.

1986-01-01

Calcium related injuries to plants grown in controlled environments under conditions which maximize plant growth rates are described. Procedures to encourage movement of calcium into developing leaves of lettuce plants were investigated. The time course and pattern of calcium accumulation was determined to develop effective control procedures for this injury, termed tipburn. Procedures investigated were: (1) increasing the relative humidity to saturation during the dark period and altering root temperatures, (2) maximizing water stress during light and minimizing water stress during dark periods, (3) shortening the light-dark cycle lengths in combination with elevated moisture levels during the dark cycles, (4) reducing nutrient concentrations and (5) vibrating the plants. Saturated humidities at night increased the rate of growth and the large fluctuation in plant water potential encouraged calcium movement to the young leaves and delayed tipburn. Root temperature regulation between 15 and 26 C was not effective in preventing tipburn. Attempts to modulate water stress produced little variation, but no difference in tipburn development. Variations in light-dark cycle lengths also had no effect on calcium concentrations within developing leaves and no variation in tipburn development. Low concentrations of nutrient solution delayed tipburn, presumably because of greater calcium transport in the low concentration plants. Shaking of the plants did not prevent tipburn, but did delay it slightly.

EqualWrites: Reducing Intra-set Write Variations for Enhancing Lifetime of Non-volatile Caches

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

Mittal, Sparsh; Vetter, Jeffrey S.

Driven by the trends of increasing core-count and bandwidth-wall problem, the size of last level caches (LLCs) has greatly increased and hence, the researchers have explored non-volatile memories (NVMs) which provide high density and consume low-leakage power. Since NVMs have low write-endurance and the existing cache management policies are write variation-unaware, effective wear-leveling techniques are required for achieving reasonable cache lifetimes using NVMs. We present EqualWrites, a technique for mitigating intra-set write variation. In this paper, our technique works by recording the number of writes on a block and changing the cache-block location of a hot data-item to redirect themore » future writes to a cold block to achieve wear-leveling. Simulation experiments have been performed using an x86-64 simulator and benchmarks from SPEC06 and HPC (high-performance computing) field. The results show that for single, dual and quad-core system configurations, EqualWrites improves cache lifetime by 6.31X, 8.74X and 10.54X, respectively. In addition, its implementation overhead is very small and it provides larger improvement in lifetime than three other intra-set wear-leveling techniques and a cache replacement policy.« less

Climate change and marine ecosystems (Invited)

NASA Astrophysics Data System (ADS)

Chavez, F.

2013-12-01

Impacts of climate variability on marine ecosystems are pervasive. Those associated with the interannual El Ni~no phenomena are the most studied and better understood. Longer term variations associated with the Atlantic Multidecadal Oscillation (AMO), the Pacific Decadal Oscillation (PDO) and the North Pacific Gyre Oscillation (NPGO) have become more evident as the present-day instrumental record has increased in length. The biological (chlorophyll to fish) and chemical (nutrients, oxygen, carbon) consequences of these climate-driven variations are discussed with an emphasis on the eastern and equatorial Pacific. During warmer periods biological productivity in the eastern Pacific is reduced and larger mobile organisms dramatically change their abundance and/or geographic distributions. At the same time biological productivity in the western Pacific increases highlighting that present (and future) climate-driven changes in biological productivity and chemical distributions are not (and will not) be uniform. The presentation documents present day variations using global scale information from satellites and in situ databases, model simulations and data collected by intensive local time series. Paradoxically longer term changes associated with phenomena like the Little Ice Age (LIA), captured in the sedimentary record, do not seem to follow the same warm (poor), cold (productive) patterns in the eastern Pacific, in fact these are reversed. The presentation ends with speculation regarding long term changes associated with a warmer world.

EqualWrites: Reducing Intra-set Write Variations for Enhancing Lifetime of Non-volatile Caches

DOE PAGES

Mittal, Sparsh; Vetter, Jeffrey S.

2015-01-29

Driven by the trends of increasing core-count and bandwidth-wall problem, the size of last level caches (LLCs) has greatly increased and hence, the researchers have explored non-volatile memories (NVMs) which provide high density and consume low-leakage power. Since NVMs have low write-endurance and the existing cache management policies are write variation-unaware, effective wear-leveling techniques are required for achieving reasonable cache lifetimes using NVMs. We present EqualWrites, a technique for mitigating intra-set write variation. In this paper, our technique works by recording the number of writes on a block and changing the cache-block location of a hot data-item to redirect themore » future writes to a cold block to achieve wear-leveling. Simulation experiments have been performed using an x86-64 simulator and benchmarks from SPEC06 and HPC (high-performance computing) field. The results show that for single, dual and quad-core system configurations, EqualWrites improves cache lifetime by 6.31X, 8.74X and 10.54X, respectively. In addition, its implementation overhead is very small and it provides larger improvement in lifetime than three other intra-set wear-leveling techniques and a cache replacement policy.« less

Mortality risk disparities in children receiving chronic renal replacement therapy for the treatment of end-stage renal disease across Europe: an ESPN-ERA/EDTA registry analysis.

PubMed

Chesnaye, Nicholas C; Schaefer, Franz; Bonthuis, Marjolein; Holman, Rebecca; Baiko, Sergey; Baskın, Esra; Bjerre, Anna; Cloarec, Sylvie; Cornelissen, Elisabeth A M; Espinosa, Laura; Heaf, James; Stone, Rosário; Shtiza, Diamant; Zagozdzon, Ilona; Harambat, Jérôme; Jager, Kitty J; Groothoff, Jaap W; van Stralen, Karlijn J

2017-05-27

We explored the variation in country mortality rates in the paediatric population receiving renal replacement therapy across Europe, and estimated how much of this variation could be explained by patient-level and country-level factors. In this registry analysis, we extracted patient data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association (ESPN/ERA-EDTA) Registry for 32 European countries. We included incident patients younger than 19 years receiving renal replacement therapy. Adjusted hazard ratios (aHR) and the explained variation were modelled for patient-level and country-level factors with multilevel Cox regression. The primary outcome studied was all-cause mortality while on renal replacement therapy. Between Jan 1, 2000, and Dec 31, 2013, the overall 5 year renal replacement therapy mortality rate was 15·8 deaths per 1000 patient-years (IQR 6·4-16·4). France had a mortality rate (9·2) of more than 3 SDs better, and Russia (35·2), Poland (39·9), Romania (47·4), and Bulgaria (68·6) had mortality rates more than 3 SDs worse than the European average. Public health expenditure was inversely associated with mortality risk (per SD increase, aHR 0·69, 95% CI 0·52-0·91) and explained 67% of the variation in renal replacement therapy mortality rates between countries. Child mortality rates showed a significant association with renal replacement therapy mortality, albeit mediated by macroeconomics (eg, neonatal mortality reduced from 1·31 [95% CI 1·13-1·53], p=0·0005, to 1·21 [0·97-1·51], p=0·10). After accounting for country distributions of patient age, the variation in renal replacement therapy mortality rates between countries increased by 21%. Substantial international variation exists in paediatric renal replacement therapy mortality rates across Europe, most of which was explained by disparities in public health expenditure, which seems to limit the availability and quality of paediatric renal care. Differences between countries in their ability to accept and treat the youngest patients, who are the most complex and costly to treat, form an important source of disparity within this population. Our findings can be used by policy makers and health-care providers to explore potential strategies to help reduce these health disparities. ERA-EDTA and ESPN. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of water table dynamics on land surface hydrologic memory

NASA Astrophysics Data System (ADS)

Lo, Min-Hui; Famiglietti, James S.

2010-11-01

The representation of groundwater dynamics in land surface models has received considerable attention in recent years. Most studies have found that soil moisture increases after adding a groundwater component because of the additional supply of water to the root zone. However, the effect of groundwater on land surface hydrologic memory (persistence) has not been explored thoroughly. In this study we investigate the effect of water table dynamics on National Center for Atmospheric Research Community Land Model hydrologic simulations in terms of land surface hydrologic memory. Unlike soil water or evapotranspiration, results show that land surface hydrologic memory does not always increase after adding a groundwater component. In regions where the water table level is intermediate, land surface hydrologic memory can even decrease, which occurs when soil moisture and capillary rise from groundwater are not in phase with each other. Further, we explore the hypothesis that in addition to atmospheric forcing, groundwater variations may also play an important role in affecting land surface hydrologic memory. Analyses show that feedbacks of groundwater on land surface hydrologic memory can be positive, negative, or neutral, depending on water table dynamics. In regions where the water table is shallow, the damping process of soil moisture variations by groundwater is not significant, and soil moisture variations are mostly controlled by random noise from atmospheric forcing. In contrast, in regions where the water table is very deep, capillary fluxes from groundwater are small, having limited potential to affect soil moisture variations. Therefore, a positive feedback of groundwater to land surface hydrologic memory is observed in a transition zone between deep and shallow water tables, where capillary fluxes act as a buffer by reducing high-frequency soil moisture variations resulting in longer land surface hydrologic memory.

Fabrication and characterization of bolus material using polydimethyl-siloxane

NASA Astrophysics Data System (ADS)

Wiratma Jaya, Gede; Sutanto, Heri

2018-01-01

Bolus has been used in radiotherapy to reduce tissue harm and to increase the superficial dose for skin cancer treatment. Commonly, a bolus is made of melamine in several hospitals. In this research, polydimethyl-siloxane (PDMS) material was used for bolus fabrication. The aims of the study are to investigate bolus density, percentage surface dose and its structural strength for each various composition. In bolus preparation, bolus material used composition variation between PDMS volume and catalyst volume. Composition variation were 20:1, 22:1, 24:1, 26:1, 28:1, 30:1 and 32:1. PDMS and catalyst were mixed by chemical solution deposition method. Bolus was molded by using glass cast with the size of 10 × 10 × 0.5 cm3. Bolus density was analyzed by mass per volume equation, for bolus radiation was examined by the linear accelerator using two electron energy (5 and 7 MeV) and bolus strain and tensile strength were examined by Brookfield CT 3 machine. The results of bolus density were similar with soft tissue density, while the lowest and highest density each variation are 22:1 and 28:1. In general, the use of bolus has increased the surface dose. Percentage of surface dose at 5 MeV energy is higher than 7 MeV energy. The highest percentage of surface dose at 5 MeV energy with 0.5 and 1.0 cm bolus thickness was achieved at composition of 32:1. For strain and tensile strength result, the lowest and highest strain each variation are 22:1 and 28:1, then the lowest and highest tensile strength each variation are 32:1 and 28:1. These results is important to select composition material for bolus fabrication in radiotherapy treatment.

Genotype-Specific Variation in the Structure of Root Fungal Communities Is Related to Chickpea Plant Productivity

PubMed Central

Hamel, Chantal; Gan, Yantai; Tar'an, Bunyamin; Knight, Joan Diane

2015-01-01

Increasing evidence supports the existence of variations in the association of plant roots with symbiotic fungi that can improve plant growth and inhibit pathogens. However, it is unclear whether intraspecific variations in the symbiosis exist among plant cultivars and if they can be used to improve crop productivity. In this study, we determined genotype-specific variations in the association of chickpea roots with soil fungal communities and evaluated the effect of root mycota on crop productivity. A 2-year field experiment was conducted in southwestern Saskatchewan, the central zone of the chickpea growing region of the Canadian prairie. The effects of 13 cultivars of chickpea, comprising a wide range of phenotypes and genotypes, were tested on the structure of root-associated fungal communities based on internal transcribed spacer (ITS) and 18S rRNA gene markers using 454 amplicon pyrosequencing. Chickpea cultivar significantly influenced the structure of the root fungal community. The magnitude of the effect varied with the genotypes evaluated, and effects were consistent across years. For example, the roots of CDC Corrine, CDC Cory, and CDC Anna hosted the highest fungal diversity and CDC Alma and CDC Xena the lowest. Fusarium sp. was dominant in chickpea roots but was less abundant in CDC Corrine than the other cultivars. A bioassay showed that certain of these fungal taxa, including Fusarium species, can reduce the productivity of chickpea, whereas Trichoderma harzianum can increase chickpea productivity. The large variation in the profile of chickpea root mycota, which included growth-promoting and -inhibiting species, supports the possibility of improving the productivity of chickpea by improving its root mycota in chickpea genetic improvement programs using traditional breeding techniques. PMID:25616789

Seasonal variation and removal efficiency of antibiotic resistance genes during wastewater treatment of swine farms.

PubMed

Sui, Qianwen; Zhang, Junya; Tong, Juan; Chen, Meixue; Wei, Yuansong

2017-04-01

The seasonal variation and removal efficiency of antibiotic resistance genes (ARGs), including tetracycline resistance genes (tetG, tetM, and tetX) and macrolide (ermB, ermF, ereA, and mefA), were investigated in two typical swine wastewater treatment systems in both winter and summer. ARGs, class 1 integron gene, and 16S rRNA gene were quantified using real-time polymerase chain reaction assays. There was a 0.31-3.52 log variation in ARGs in raw swine wastewater, and the abundance of ARGs in winter was higher than in summer. tetM, tetX, ermB, ermF, and mefA were highly abundant. The abundance of ARGs was effectively reduced by most individual treatment process and the removal efficiencies of ARGs were higher in winter than in summer. However, when examining relative abundance, the fate of ARGs was quite variable. Anaerobic digestion reduced the relative abundance of tetX, ermB, ermF, and mefA, while lagoon treatment decreased tetM, ermB, ermF, and mefA. Sequencing batch reactor (SBR) decreased tetM, ermB, and ermF, but biofilters and wetlands did not display consistent removal efficiency on ARGs in two sampling seasons. As far as the entire treatment system is concerned, ermB and mefA were effectively reduced in both winter and summer in both total and relative abundance. The relative abundances of tetG and ereA were significantly correlated with intI1 (p < 0.01), and both tetG and ereA increased after wastewater treatment. This may pose a great threat to public health.

Seasonal and spatial patterns of growth of rainbow trout in the Colorado River in Grand Canyon, AZ

USGS Publications Warehouse

Yard, Micheal D.; Korman, Josh; Walters, Carl J.; Kennedy, T.A.

2016-01-01

Rainbow trout (Oncorhynchus mykiss) have been purposely introduced in many regulated rivers, with inadvertent consequences on native fishes. We describe how trout growth rates and condition could be influencing trout population dynamics in a 130 km section of the Colorado River below Glen Canyon Dam based on a large-scale mark–recapture program where ∼8000 rainbow trout were recaptured over a 3-year period (2012–2014). There were strong temporal and spatial variations in growth in both length and weight as predicted from von Bertalanffy and bioenergetic models, respectively. There was more evidence for seasonal variation in the growth coefficient and annual variation in the asymptotic length. Bioenergetic models showed more variability for growth in weight across seasons and years than across reaches. These patterns were consistent with strong seasonal variation in invertebrate drift and effects of turbidity on foraging efficiency. Highest growth rates and relative condition occurred in downstream reaches with lower trout densities. Results indicate that reduction in rainbow trout abundance in Glen Canyon will likely increase trout size in the tailwater fishery and may reduce downstream dispersal into Grand Canyon.

Perils and pitfalls of reporting sex differences

PubMed Central

Maney, Donna L.

2016-01-01

The idea of sex differences in the brain both fascinates and inflames the public. As a result, the communication and public discussion of new findings is particularly vulnerable to logical leaps and pseudoscience. A new US National Institutes of Health policy to consider both sexes in almost all preclinical research will increase the number of reported sex differences and thus the risk that research in this important area will be misinterpreted and misrepresented. In this article, I consider ways in which we might reduce that risk, for example, by (i) employing statistical tests that reveal the extent to which sex explains variation, rather than whether or not the sexes ‘differ’, (ii) properly characterizing the frequency distributions of scores or dependent measures, which nearly always overlap, and (iii) avoiding speculative functional or evolutionary explanations for sex-based variation, which usually invoke logical fallacies and perpetuate sex stereotypes. Ultimately, the factor of sex should be viewed as an imperfect, temporary proxy for yet-unknown factors, such as hormones or sex-linked genes, that explain variation better than sex. As scientists, we should be interested in discovering and understanding the true sources of variation, which will be more informative in the development of clinical treatments. PMID:26833839

Optimization of equivalent uniform dose using the L-curve criterion.

PubMed

Chvetsov, Alexei V; Dempsey, James F; Palta, Jatinder R

2007-10-07

Optimization of equivalent uniform dose (EUD) in inverse planning for intensity-modulated radiation therapy (IMRT) prevents variation in radiobiological effect between different radiotherapy treatment plans, which is due to variation in the pattern of dose nonuniformity. For instance, the survival fraction of clonogens would be consistent with the prescription when the optimized EUD is equal to the prescribed EUD. One of the problems in the practical implementation of this approach is that the spatial dose distribution in EUD-based inverse planning would be underdetermined because an unlimited number of nonuniform dose distributions can be computed for a prescribed value of EUD. Together with ill-posedness of the underlying integral equation, this may significantly increase the dose nonuniformity. To optimize EUD and keep dose nonuniformity within reasonable limits, we implemented into an EUD-based objective function an additional criterion which ensures the smoothness of beam intensity functions. This approach is similar to the variational regularization technique which was previously studied for the dose-based least-squares optimization. We show that the variational regularization together with the L-curve criterion for the regularization parameter can significantly reduce dose nonuniformity in EUD-based inverse planning.

Ability of calibration phantom to reduce the interscan variability in electron beam computed tomography.

PubMed

Budoff, Matthew J; Mao, Songshou; Lu, Bin; Takasu, Junichiro; Child, Janis; Carson, Sivi; Fisher, Hans

2002-01-01

To test the hypothesis that a calibration phantom would improve interpatient and interscan variability in coronary artery calcium (CAC) studies. We scanned 144 patients twice with or without the calibration phantom and then scanned 93 patients with a single calcific lesion twice and, finally, scanned a cork heart with calcific foci. There were no linear correlations in computed tomography Hounsfield unit (CT HU) and CT HU interscan variation between blood pool and phantom plugs at any slice level in patient groups (p > 0.05). The CT HU interscan variation in phantom plugs (2.11 HU) was less than that of the blood pool (3.47 HU; p < 0.05) and CAC lesion (20.39; p < 0.001). Comparing images with and without a calibration phantom, there was a significant decrease in CT HU as well as an increase in noise and peak values in patient studies and the cork phantom study. The CT HU attenuation variations of the interpatient and interscan blood pool, calibration phantom plug, and cork coronary arteries were not parallel. Therefore, the ability to adjust the CT HU variation of calcific lesions by a calibration phantom is problematic and may worsen the problem.

Comparative analyses of fungicide sensitivity and SSR marker variations indicate a low risk of developing azoxystrobin resistance in Phytophthora infestans

PubMed Central

Qin, Chun-Fang; He, Meng-Han; Chen, Feng-Ping; Zhu, Wen; Yang, Li-Na; Wu, E-Jiao; Guo, Zheng-Liang; Shang, Li-Ping; Zhan, Jiasui

2016-01-01

Knowledge of the evolution of fungicide resistance is important in securing sustainable disease management in agricultural systems. In this study, we analyzed and compared the spatial distribution of genetic variation in azoxystrobin sensitivity and SSR markers in 140 Phytophthora infestans isolates sampled from seven geographic locations in China. Sensitivity to azoxystrobin and its genetic variation in the pathogen populations was measured by the relative growth rate (RGR) at four fungicide concentrations and determination of the effective concentration for 50% inhibition (EC50). We found that all isolates in the current study were sensitive to azoxystrobin and their EC50 was similar to that detected from a European population about 20 years ago, suggesting the risk of developing azoxystrobin resistance in P. infestans populations is low. Further analyses indicate that reduced genetic variation and high fitness cost in resistant mutations are the likely causes for the low evolutionary likelihood of developing azoxystrobin resistance in the pathogen. We also found a negative correlation between azoxystrobin tolerance in P. infestans populations and the mean annual temperature of collection sites, suggesting that global warming may increase the efficiency of using the fungicide to control the late blight. PMID:26853908

Comparative analyses of fungicide sensitivity and SSR marker variations indicate a low risk of developing azoxystrobin resistance in Phytophthora infestans.

PubMed

Qin, Chun-Fang; He, Meng-Han; Chen, Feng-Ping; Zhu, Wen; Yang, Li-Na; Wu, E-Jiao; Guo, Zheng-Liang; Shang, Li-Ping; Zhan, Jiasui

2016-02-08

Knowledge of the evolution of fungicide resistance is important in securing sustainable disease management in agricultural systems. In this study, we analyzed and compared the spatial distribution of genetic variation in azoxystrobin sensitivity and SSR markers in 140 Phytophthora infestans isolates sampled from seven geographic locations in China. Sensitivity to azoxystrobin and its genetic variation in the pathogen populations was measured by the relative growth rate (RGR) at four fungicide concentrations and determination of the effective concentration for 50% inhibition (EC50). We found that all isolates in the current study were sensitive to azoxystrobin and their EC50 was similar to that detected from a European population about 20 years ago, suggesting the risk of developing azoxystrobin resistance in P. infestans populations is low. Further analyses indicate that reduced genetic variation and high fitness cost in resistant mutations are the likely causes for the low evolutionary likelihood of developing azoxystrobin resistance in the pathogen. We also found a negative correlation between azoxystrobin tolerance in P. infestans populations and the mean annual temperature of collection sites, suggesting that global warming may increase the efficiency of using the fungicide to control the late blight.

Excitonic fine-structure splitting in telecom-wavelength InAs/GaAs quantum dots: Statistical distribution and height-dependence

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

Goldmann, Elias, E-mail: goldmann@itp.uni-bremen.de; Barthel, Stefan; Florian, Matthias

The variation of the excitonic fine-structure splitting is studied for semiconductor quantum dots under the influence of a strain-reducing layer, utilized to shift the emission wavelength of the excitonic transition into the telecom-wavelength regime of 1.3–1.5 μm. By means of a sp{sup 3}s{sup *}-tight-binding model and configuration interaction, we calculate wavelength shifts and fine-structure splittings for various quantum dot geometries. We find the splittings remaining small and even decreasing with strain-reducing layer composition for quantum dots with large height. Combined with an observed increased emission efficiency, the applicability for generation of entanglement photons is persistent.

Does plant architectural complexity increase with increasing habitat complexity? A test with a pioneer shrub in the Brazilian Cerrado.

PubMed

Silveira, F A O; Oliveira, E G

2013-05-01

Understanding variation in plant traits in heterogeneous habitats is important to predict responses to changing environments, but trait-environment associations are poorly known along ecological gradients. We tested the hypothesis that plant architectural complexity increases with habitat complexity along a soil fertility gradient in a Cerrado (Neotropical savanna) area in southeastern Brazil. Plant architecture and productivity (estimated as the total number of healthy infructescences) of Miconia albicans (SW.) Triana were examined in three types of vegetation which together form a natural gradient of increasing soil fertility, tree density and canopy cover: grasslands (campo sujo, CS), shrublands (cerrado sensu strico, CE) and woodlands (cerradão, CD). As expected, plants growing at the CS were shorter and had a lower branching pattern, whereas plants at the CD were the tallest. Unexpectedly, however, CD plants did not show higher architectural complexity compared to CE plants. Higher architectural similarity between CE and CD plants compared to similarity between CS and CE plants suggests reduced expression of functional architectural traits under shade. Plants growing at the CE produced more quaternary shoots, leading to a larger number of infructescences. This higher plant productivity in CE indicates that trait variation in ecological gradients is more complex than previously thought. Nematode-induced galls accounted for fruit destruction in 76.5% infructescences across physiognomies, but percentage of attack was poorly related to architectural variables. Our data suggest shade-induced limitation in M. albicans architecture, and point to complex phenotypic variation in heterogeneous habitats in Neotropical savannas.

Additive effects of oxytocin receptor gene polymorphisms on reward circuitry in youth with autism.

PubMed

Hernandez, L M; Krasileva, K; Green, S A; Sherman, L E; Ponting, C; McCarron, R; Lowe, J K; Geschwind, D H; Bookheimer, S Y; Dapretto, M

2017-08-01

Several common alleles in the oxytocin receptor gene (OXTR) are associated with altered brain function in reward circuitry in neurotypical adults and may increase risk for autism spectrum disorders (ASD). Yet, it is currently unknown how variation in the OXTR relates to brain functioning in individuals with ASD, and, critically, whether neural endophenotypes vary as a function of aggregate genetic risk. Here, for we believe the first time, we use a multi-locus approach to examine how genetic variation across several OXTR single-nucleotide polymorphisms (SNPs) affect functional connectivity of the brain's reward network. Using data from 41 children with ASD and 41 neurotypical children, we examined functional connectivity of the nucleus accumbens (NAcc) - a hub of the reward network - focusing on how connectivity varies with OXTR risk-allele dosage. Youth with ASD showed reduced NAcc connectivity with other areas in the reward circuit as a function of increased OXTR risk-allele dosage, as well as a positive association between risk-allele dosage and symptom severity, whereas neurotypical youth showed increased NAcc connectivity with frontal brain regions involved in mentalizing. In addition, we found that increased NAcc-frontal cortex connectivity in typically developing youth was related to better scores on a standardized measure of social functioning. Our results indicate that cumulative genetic variation on the OXTR impacts reward system connectivity in both youth with ASD and neurotypical controls. By showing differential genetic effects on neuroendophenotypes, these pathways elucidate mechanisms of vulnerability versus resilience in carriers of disease-associated risk alleles.

Avoidable hospitalizations in Switzerland: a small area analysis on regional variation, density of physicians, hospital supply and rurality.

PubMed

Berlin, Claudia; Busato, André; Rosemann, Thomas; Djalali, Sima; Maessen, Maud

2014-07-03

Avoidable hospitalizations (AH) are hospital admissions for diseases and conditions that could have been prevented by appropriate ambulatory care. We examine regional variation of AH in Switzerland and the factors that determine AH. We used hospital service areas, and data from 2008-2010 hospital discharges in Switzerland to examine regional variation in AH. Age and sex standardized AH were the outcome variable, and year of admission, primary care physician density, medical specialist density, rurality, hospital bed density and type of hospital reimbursement system were explanatory variables in our multilevel poisson regression. Regional differences in AH were as high as 12-fold. Poisson regression showed significant increase of all AH over time. There was a significantly lower rate of all AH in areas with more primary care physicians. Rates increased in areas with more specialists. Rates of all AH also increased where the proportion of residences in rural communities increased. Regional hospital capacity and type of hospital reimbursement did not have significant associations. Inconsistent patterns of significant determinants were found for disease specific analyses. The identification of regions with high and low AH rates is a starting point for future studies on unwarranted medical procedures, and may help to reduce their incidence. AH have complex multifactorial origins and this study demonstrates that rurality and physician density are relevant determinants. The results are helpful to improve the performance of the outpatient sector with emphasis on local context. Rural and urban differences in health care delivery remain a cause of concern in Switzerland.

Near-ambient ozone concentrations reduce the vigor of Betula and Populus species in Finland.

PubMed

Oksanen, Elina; Manninen, Sirkku; Vapaavuori, Elina; Holopainen, Toini

2009-12-01

In this review the main growth responses of Finnish birch (Betula pendula, B. pubescens) and aspen species (Populus tremula and P. tremuloides x P. tremula) are correlated with ozone exposure, indicated as the AOT40 value. Data are derived from 23 different laboratory, open-top chamber, and free-air fumigation experiments. Our results indicate that these tree species are sensitive to increasing ozone concentrations, though high intraspecific variation exists. The roots are the most vulnerable targets in both genera. These growth reductions, determined from trees grown under optimal nutrient and water supply, were generally accompanied by increased visible foliar injuries, carbon allocation toward defensive compounds, reduced carbohydrate contents of leaves, impaired photosynthesis processes, disturbances in stomatal function, and earlier autumn senescence. Because both genera have shown complex ozone defense and response mechanisms, which are modified by variable environmental conditions, a mechanistically based approach is necessary for accurate ozone risk assessment.

Effect of flour processing on the quality characteristics of a soy-based beverage.

PubMed

Arif, Sara; Ahmad, Asif; Masud, Tariq; Khalid, Nauman; Hayat, Imran; Siddique, Farzana; Ali, Muhammad

2012-12-01

Four treatments (roasting, germination, autoclaving and an application of 0.5% EDTA+0.5% sodium hydroxide) were used to reduce the beany flavour of soya beans to produce a soy-based beverage. While germination significantly increased the protein level as compared to the other treatments, the maximum reduction of the beany flavour was achieved by the 0.5% EDTA+0.5% sodium hydroxide application. The soya beans that underwent this treatment were used during the second phase for optimized beverage formulation. During the second phase, a beverage was prepared according to different formulations and analysed for chemical composition and total viable count during a two-month storage period. During storage, the beverage samples exhibited variations in several parameters. The acidity, reducing sugars and total sugars increased, while the ascorbic acid, total soluble solids and pH decreased. Overall, chemical and microbial analyses showed the stability of the product during the storage period.

Measured particulate behavior in a subscale solid propellant rocket motor

NASA Astrophysics Data System (ADS)

Brennan, W. D.; Hovland, D. L.; Netzer, D. W.

1992-10-01

Particulate matter are sized in the exhaust nozzle and plume of small rocket motors of varying geometry to assess the effects of the expansion process on particle size. Both converging and converging-diverging nozzles are considered, and particle sizing is accomplished at pressures of up to 4.36 MPa with aluminum loadings of 2.0 and 4.7 percent. An instrument based on Fraunhofer diffraction is used to measure the particle-size distributions showing that: (1) high burning rates reduce particle agglomeration and increase C* efficiency; (2) high pressures lead to small and monomodal D32 entering the nozzle; and (3) D32 sizes increase appreciably at the tailoff. Some variations in plume signature are theorized to be caused by the tailoff phenomenon, and particle collisions and/or surface effects in the nozzle convergence are suggested by the reduced number of larger particles at the nozzle convergence.

An Avoidance Model for Short-Range Order Induced by Soft Repulsions in Systems of Rigid Rods

NASA Astrophysics Data System (ADS)

Han, Jining; Herzfeld, Judith

1996-03-01

The effects of soft repulsions on hard particle systems are calculated using an avoidance model which improves upon the simple mean field approximation. Avoidance reduces, but does not eliminate, the energy due to soft repulsions. On the other hand, it also reduces the configurational entropy. Under suitable conditions, this simple trade-off yields a free energy that is lower than the mean field value. In these cases, the variationally determined avoidance gives an estimate for the short-range positional order induced by soft repulsions. The results indicate little short-range order for isotropically oriented rods. However, for parallel rods, short-range order increases to significant levels as the particle axial ratio increases. The implications for long- range positional ordering are also discussed. In particular, avoidance may explain the smectic ordering of tobacco mosaic virus at volume fractions lower than those necessary for smectic ordering of hard particles.

Photoluminescence of Reduced Graphene Oxide Prepared from Old Coconut Shell with Carbonization Process at Varying Temperatures

NASA Astrophysics Data System (ADS)

Jayanti, Dwi Noor; Yogi Nugraheni, Ananda; Kurniasari; Anjelh Baqiya, Malik; Darminto

2017-05-01

Reduced graphene oxide (rGO) powder has been prepared from coconut shells by carbonization process at 400°C, 600°C, 800°C and 1000°C for 5 hours at ambient air. In this study the exfoliation rGO was added into distilled water with variation of concentration solution using the sonication process for 3 hours and centrifugation at 4000 rpm for 20 minutes. The characterization were performed by using XRD and photoluminescence (PL) spectroscopy. The photoluminescence or rGO showed the peak of excitation and emission at wavelengths ranging from 340 nm to 800 nm. The PL emission spectra are at wavelength ranging from UV to visible region approaching red. Observation showed that the photoluminescence intensity was significantly increased by the increasing content of rGO in the solution. The influence of the varying temperature on the PL spectra will also be discussed in this study.

Sourdough fermentation and chestnut flour in gluten-free bread: A shelf-life evaluation.

PubMed

Rinaldi, Massimiliano; Paciulli, Maria; Caligiani, Augusta; Scazzina, Francesca; Chiavaro, Emma

2017-06-01

The effect of sourdough fermentation combined with chestnut flour was investigated for improving technological and nutritional quality of gluten-free bread during 5day shelf life by means of chemico-physical and nutritional properties. Sourdough fermentation by itself and with chestnut flour reduced volume of loaves and heterogeneity in crumb grain. Sourdough technology allowed increasing crumb moisture content with no significant variations during shelf-life. Chestnut flour darkened crumb and crust while no effects on colour were observed for sourdough. Sourdough and/or chestnut flour addition caused a significant increase in crumb hardness at time 0 while a significant reduction of staling was observed only at 5days, even if a decrease in amylopectin fusion enthalpy was observed. The percentage of hydrolysed starch during in vitro digestion was significantly reduced by sourdough fermentation with a presumable lower glycaemic index. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of fuel processes on heavy duty automotive diesel engine emissions

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

Reynolds, E.G.

1995-12-31

The effect of fuel quality on exhaust emissions from 2 heavy duty diesel engines has been measured over the ECE R49 test cycle. The engines were selected to represent technologies used to meet Euro 1 and 2 emission standards (1992/93 and 1995/96); engines 1 and 2 respectively. The test fuels were prepared by a combination of processing, blending and additive treatment. When comparing the emissions from engines 1 and 2, using base line data generated on the CEC reference fuel RF73-T-90, engine technology had the major effect on emission levels. Engine 2 reduced both particulate matter (PM) and carbon monoxidemore » levels by approximately 50%, with total hydrocarbon (THC) being approximately 75% lower. Oxides of nitrogen levels were similar for both engines. The variations in test fuel quality had marginal effects on emissions, with the two engines giving directionally opposite responses in some cases. For instance, there was an effect on CO and NOx but where one engine showed a reduction the other gave an increase. There were no significant changes in THC emissions from either engine when operating on any of the test fuels. When the reference fuel was hydrotreated, engine 1 showed a trend towards reduced particulate and NOx but with CO increasing. Engine 2 also showed a trend for reduced particulate levels, with an increase in NOx and no change in CO. Processing to reduce the final boiling point of the reference fuel showed a trend towards reduced particulate emissions with CO increasing on engine 1 but decreasing on engine 2.« less

Foot-strike haemolysis after a 60-km ultramarathon.

PubMed

Lippi, Giuseppe; Schena, Federico; Salvagno, Gian Luca; Aloe, Rosalia; Banfi, Giuseppe; Guidi, Gian Cesare

2012-07-01

The various contributors to sport-related anaemia include increased plasma volume, exercise-induced oxidative stress, increased body temperature, acidosis, gastrointestinal bleeding, acute and chronic inflammation as well as compression and damage of red blood cells (RBC) in the capillaries within the contracting muscles. The effective contribution of foot-strike haemolysis is unclear. We studied 18 Caucasian male athletes (mean age, 42 years; range, 34-52 years) before and immediately after a 60-km ultramarathon. Laboratory investigations included the haematological profile along with haptoglobin, potassium, aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH) and albumin concentrations and a haemolysis index (HI). No significant variations were found in post-exercise values of haemoglobin, RBC count and haematocrit. Mean corpuscular volume and haptoglobin were significantly decreased, whereas RBC distribution width was increased. The concentration of haptoglobin was reduced by approximately 50%, whereas enzyme concentrations were all remarkably increased. The HI remained below 0.5 g/L. After adjusting for plasma volume change, the increases were 1.7% for potassium (P=0.17), 30% for AST (P<0.01), 49% for LDH (P<0.01) and 2.39-fold for CK (P<0.01). A statistically significant association was found between haemoconcentration-adjusted variations of CK and those of AST (r=0.803; P<0.01) and LDH (r=0.551; P=0.02). This is the first study demonstrating that long-distance running does not induce clinically significant changes in haemoglobin, haematocrit, RBC count or potassium concentration. The significant post-exercise decrease of haptoglobin reflects a certain degree of haemolysis, but the concentration of cell-free haemoglobin remaining below 0.5 g/L and the non-significant variation in RBC count both indicate that the foot-strike haemolysis is very modest or even clinically negligible.

Cardiorespiratory fitness as a predictor of intestinal microbial diversity and distinct metagenomic functions.

PubMed

Estaki, Mehrbod; Pither, Jason; Baumeister, Peter; Little, Jonathan P; Gill, Sandeep K; Ghosh, Sanjoy; Ahmadi-Vand, Zahra; Marsden, Katelyn R; Gibson, Deanna L

2016-08-08

Reduced microbial diversity in human intestines has been implicated in various conditions such as diabetes, colorectal cancer, and inflammatory bowel disease. The role of physical fitness in the context of human intestinal microbiota is currently not known. We used high-throughput sequencing to analyze fecal microbiota of 39 healthy participants with similar age, BMI, and diets but with varying cardiorespiratory fitness levels. Fecal short-chain fatty acids were analyzed using gas chromatography. We showed that peak oxygen uptake (VO2peak), the gold standard measure of cardiorespiratory fitness, can account for more than 20 % of the variation in taxonomic richness, after accounting for all other factors, including diet. While VO2peak did not explain variation in beta diversity, it did play a significant role in explaining variation in the microbiomes' predicted metagenomic functions, aligning positively with genes related to bacterial chemotaxis, motility, and fatty acid biosynthesis. These predicted functions were supported by measured increases in production of fecal butyrate, a short-chain fatty acid associated with improved gut health, amongst physically fit participants. We also identified increased abundances of key butyrate-producing taxa (Clostridiales, Roseburia, Lachnospiraceae, and Erysipelotrichaceae) amongst these individuals, which likely contributed to the observed increases in butyrate levels. Results from this study show that cardiorespiratory fitness is correlated with increased microbial diversity in healthy humans and that the associated changes are anchored around a set of functional cores rather than specific taxa. The microbial profiles of fit individuals favor the production of butyrate. As increased microbiota diversity and butyrate production is associated with overall host health, our findings warrant the use of exercise prescription as an adjuvant therapy in combating dysbiosis-associated diseases.

Cerebral ischemia and reperfusion increases the heterogeneity of local oxygen supply/consumption balance.

PubMed

Weiss, Harvey R; Grayson, Jeremy; Liu, Xia; Barsoum, Sylviana; Shah, Harsh; Chi, Oak Z

2013-09-01

After cerebral vessel blockage, local blood flow and O2 consumption becomes lower and oxygen extraction increases. With reperfusion, blood flow is partially restored. We examined the effects of ischemia-reperfusion on the heterogeneity of local venous oxygen saturation in rats in order to determine the pattern of microregional O2 supply/consumption balance in reperfusion. The middle cerebral artery was blocked for 1 hour using the internal carotid approach in 1 group (n=9) and was then reperfused for 2 hours in another group (n=9) of isoflurane-anesthetized rats. Regional cerebral blood flow was determined using a C(14)-iodoantipyrine autoradiographic technique. Regional small vessel arterial and venous oxygen saturations were determined microspectrophotometrically. After 1 hour of ischemia, local cerebral blood flow (92±10 versus 50±10 mL/min per 100 g) and O2 consumption (4.5±0.6 versus 2.7±0.5 mL O2/min per 100 g) decreased compared with the contralateral cortex. Oxygen extraction increased (4.7±0.2 versus 5.4±0.3 mL O2/100 mL) and the variation in small vein (20-60 μm) O2 saturation as determined by its coefficient of variation (=100×SD/mean) increased (5.5 versus 10.5). With 2 hours of reperfusion, the blood flow decrement was reduced and O2 consumption returned to the value in the contralateral cortex. Oxygen extraction remained elevated in the ischemic-reperfused area and the coefficient of variation of small vein O2 saturation increased further (17.3). These data indicated continued reduction of O2 supply/consumption balance with reperfusion. They also demonstrated many small regions of low oxygenation within the reperfused cortical region.

Geotechnical properties of municipal solid waste at different phases of biodegradation

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

Reddy, Krishna R., E-mail: kreddy@uic.edu; Hettiarachchi, Hiroshan, E-mail: hiroshan@ltu.edu; Gangathulasi, Janardhanan, E-mail: jganga2@uic.edu

Highlights: > Degraded synthetic municipal solid waste (MSW) anaerobically in controlled bench-scale reactors. > Performed laboratory tests to determine geotechnical properties of MSW at different phases of degradation. > Hydraulic conductivity decreased by two orders of magnitude due to degradation. > Compression ratio reduced from 0.34 for initial fresh waste to 0.15 for the mostly degraded waste. > Friction angle reduced, but cohesion increased with degradation. - Abstract: This paper presents the results of laboratory investigation conducted to determine the variation of geotechnical properties of synthetic municipal solid waste (MSW) at different phases of degradation. Synthetic MSW samples were preparedmore » based on the composition of MSW generated in the United States and were degraded in bioreactors with leachate recirculation. Degradation of the synthetic MSW was quantified based on the gas composition and organic content, and the samples exhumed from the bioreactor cells at different phases of degradation were tested for the geotechnical properties. Hydraulic conductivity, compressibility and shear strength of initial and degraded synthetic MSW were all determined at constant initial moisture content of 50% on wet weight basis. Hydraulic conductivity of synthetic MSW was reduced by two orders of magnitude due to degradation. Compression ratio was reduced from 0.34 for initial fresh waste to 0.15 for the mostly degraded waste. Direct shear tests showed that the fresh and degraded synthetic MSW exhibited continuous strength gain with increase in horizontal deformation, with the cohesion increased from 1 kPa for fresh MSW to 16-40 kPa for degraded MSW and the friction angle decreased from 35{sup o} for fresh MSW to 28{sup o} for degraded MSW. During the triaxial tests under CU condition, the total strength parameters, cohesion and friction angle, were found to vary from 21 to 57 kPa and 1{sup o} to 9{sup o}, respectively, while the effective strength parameters, cohesion and friction angle varied from 18 to 56 kPa and from 1{sup o} to 11{sup o}, respectively. Similar to direct shear test results, as the waste degrades an increase in cohesion and slight decrease in friction angle was observed. Decreased friction angle and increased cohesion with increased degradation is believed to be due to the highly cohesive nature of the synthetic MSW. Variation of synthetic MSW properties from this study also suggests that significant changes in geotechnical properties of MSW can occur due to enhanced degradation induced by leachate recirculation.« less

Soil properties drive a negative correlation between species diversity and genetic diversity in a tropical seasonal rainforest

PubMed Central

Xu, Wumei; Liu, Lu; He, Tianhua; Cao, Min; Sha, Liqing; Hu, Yuehua; Li, Qiaoming; Li, Jie

2016-01-01

A negative species-genetic diversity correlation (SGDC) could be predicted by the niche variation hypothesis, whereby an increase in species diversity within community reduces the genetic diversity of the co-occurring species because of the reduction in average niche breadth; alternatively, competition could reduce effective population size and therefore genetic diversity of the species within community. We tested these predictions within a 20 ha tropical forest dynamics plot (FDP) in the Xishuangbanna tropical seasonal rainforest. We established 15 plots within the FDP and investigated the soil properties, tree diversity, and genetic diversity of a common tree species Beilschmiedia roxburghiana within each plot. We observed a significant negative correlation between tree diversity and the genetic diversity of B. roxburghiana within the communities. Using structural equation modeling, we further determined that the inter-plot environmental characteristics (soil pH and phosphorus availability) directly affected tree diversity and that the tree diversity within the community determined the genetic diversity of B. roxburghiana. Increased soil pH and phosphorus availability might promote the coexistence of more tree species within community and reduce genetic diversity of B. roxburghiana for the reduced average niche breadth; alternatively, competition could reduce effective population size and therefore genetic diversity of B. roxburghiana within community. PMID:26860815

Soil nitrate reducing processes – drivers, mechanisms for spatial variation, and significance for nitrous oxide production

PubMed Central

Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M.; Daniell, Tim J.

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3−) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub centimeter areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location, and potential for N2O production from soils. PMID:23264770

Soil nitrate reducing processes - drivers, mechanisms for spatial variation, and significance for nitrous oxide production.

PubMed

Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M; Daniell, Tim J

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate ([Formula: see text]) and production of the potent greenhouse gas, nitrous oxide (N(2)O). A number of factors are known to control these processes, including O(2) concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub centimeter areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location, and potential for N(2)O production from soils.

Soil properties drive a negative correlation between species diversity and genetic diversity in a tropical seasonal rainforest.

PubMed

Xu, Wumei; Liu, Lu; He, Tianhua; Cao, Min; Sha, Liqing; Hu, Yuehua; Li, Qiaoming; Li, Jie

2016-02-10

A negative species-genetic diversity correlation (SGDC) could be predicted by the niche variation hypothesis, whereby an increase in species diversity within community reduces the genetic diversity of the co-occurring species because of the reduction in average niche breadth; alternatively, competition could reduce effective population size and therefore genetic diversity of the species within community. We tested these predictions within a 20 ha tropical forest dynamics plot (FDP) in the Xishuangbanna tropical seasonal rainforest. We established 15 plots within the FDP and investigated the soil properties, tree diversity, and genetic diversity of a common tree species Beilschmiedia roxburghiana within each plot. We observed a significant negative correlation between tree diversity and the genetic diversity of B. roxburghiana within the communities. Using structural equation modeling, we further determined that the inter-plot environmental characteristics (soil pH and phosphorus availability) directly affected tree diversity and that the tree diversity within the community determined the genetic diversity of B. roxburghiana. Increased soil pH and phosphorus availability might promote the coexistence of more tree species within community and reduce genetic diversity of B. roxburghiana for the reduced average niche breadth; alternatively, competition could reduce effective population size and therefore genetic diversity of B. roxburghiana within community.

Seasonal variation of selenium in outdoor experimental stream-wetland systems

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

Allen, K.N.

Two outdoor experimental stream-wetland systems were exposed continuously to 10 {mu}g/L Se(IV) over a 2-yr period. A seasonal variation in the water column Se concentrations was found in wetlands; a comparable variation was not observed in the stream segment. Water column Se was never reduced by more than 20% in the streams, but was reduced by greater than 90% in midsummer in the wetlands. Accumulation of Se in plants was much higher in the wetlands than in the streams, particularly in duckweed (Lemma minor). The deposition of Se in sediments was extremely variable within the wetlands.

Seasonal variations in production and consumption rates of dissolved organic carbon in an organic-rich coastal sediment

NASA Astrophysics Data System (ADS)

Alperin, M. J.; Albert, D. B.; Martens, C. S.

1994-11-01

Dissolved organic carbon (DOC) concentrations in anoxic marine sediments are controlled by at least three processes: (1) production of nonvolatile dissolved compounds, such as peptides and amino acids, soluble saccharides and fatty acids, via hydrolysis of particulate organic carbon (POC). (2) conversion of these compounds to volatile fatty acids and alcohols by fermentative bacteria. (3) consumption of volatile fatty acids and alcohols by terminal bacteria, such as sulfate reducers and methanogens. We monitored seasonal changes in concentration profiles of total DOC, nonacid-volatile (NAV) DOC and acid-volatile (AV) DOC in anoxic sediment from Cape Lookout Bight, North Carolina, USA, in order to investigate the factors that control seasonal variations in rates of hydrolysis, fermentation, and terminal metabolism. During the winter months, DOC concentrations increased continuously from 0.2 mM in the bottomwater to ~4 mM at a depth of 36 cm in the sediment column. During the summer, a large DOC maximum developed between 5 and 20 cm, with peak concentrations approaching 10 mM. The mid-depth summertime maximum was driven by increases in both NAV- and AV-DOC concentrations. Net NAV-DOC reaction rates were estimated by a diagenetic model applied to NAV-DOC concentration profiles. Depth-integrated production rates of NAV-DOC increased from February through July, suggesting that net rates of POC hydrolysis during this period are controlled by temperature. Net consumption of NAV-DOC during the late summer and early fall suggests reduced gross NAV-DOC production rates, presumably due to a decline in the availability of labile POC. A distinct subsurface peak in AV-DOC concentration developed during the late spring, when the sulfate depletion depth shoaled from 25 to 10 cm. We hypothesize that the AV-DOC maximum results from a decline in consumption by sulfate-reducing bacteria (due to sulfate limitation) and a lag in the development of an active population of methanogenic bacteria. A diagenetic model that incorporates a lag period in the sulfate reducer-methanogen transition successfully simulates the timing, magnitude, depth and shape of the AV-DOC peak.

Latitudinal variation in ambient UV-B radiation is an important determinant of Lolium perenne forage production, quality, and digestibility

PubMed Central

Comont, David; Winters, Ana; Gomez, Leonardo D; McQueen-Mason, Simon J; Gwynn-Jones, Dylan

2013-01-01

Few studies to date have considered the responses of agriculturally important forage grasses to UV-B radiation. Yet grasses such as Lolium perenne have a wide current distribution, representing exposure to a significant variation in ambient UV-B. The current study investigated the responses of L. perenne (cv. AberDart) to a simulated latitudinal gradient of UV-B exposure, representing biologically effective UV-B doses at simulated 70, 60, 50, 40, and 30° N latitudes. Aspects of growth, soluble compounds, and digestibility were assessed, and results are discussed in relation to UV-B effects on forage properties and the implications for livestock and bio-ethanol production. Aboveground biomass production was reduced by approximately 12.67% with every 1 kJ m–2 day–1 increase in biologically weighted UV-B. As a result, plants grown in the highest UV-B treatment had a total biomass of just 13.7% of controls. Total flavonoids were increased by approximately 76% by all UV-B treatments, while hydroxycinnamic acids increased in proportion to the UV-B dose. Conversely, the digestibility of the aboveground biomass and concentrations of soluble fructans were reduced by UV-B exposure, although soluble sucrose, glucose, and fructose concentrations were unaffected. These results highlight the capacity for UV-B to directly affect forage productivity and chemistry, with negative consequences for digestibility and bioethanol production. Results emphasize the need for future development and distribution of L. perenne varieties to take UV-B irradiance into consideration. PMID:23580749

Computer simulation of single-phase nanocrystalline permanent magnets

NASA Astrophysics Data System (ADS)

Griffiths, M. K.; Bishop, J. E. L.; Tucker, J. W.; Davies, H. A.

1998-03-01

Demagnetizing curves have been calculated numerically for three-dimensional micromagnetic model assemblies of randomly oriented, magnetically hard, exchange coupled, uniaxial nanocrystals as typified by rapidly quenched Nd 2Fe 14B. The curves were obtained as a sequence of static equilibrium states in an incrementally changing applied field. The magnetization distribution in each state was obtained by minimizing the sum of the exchange, anisotropy and Zeeman energies of the assembly, using a modified LaBonte method, with computational elements as small as 1.11 nm (roughly {1}/{4} the domain wall thickness in Nd 2Fe 14B). For computational economy, internal dipolar interactions were ignored in the energy minimization. For a material with the magnetic constants of stoichiometric Nd 2Fe 14B, tests showed that these interactions contribute less than 3% to the energy. On increasing the model grain size from 4.4 to 36 nm, the reduced remanence fell from 76 to 54% and the reduced intrinsic coercivity μ0iHCMS/ KU increased from 0.16 to 0.46 (just under half the Stoner-Wohlfarth value); both sets of results are in reasonable agreement with experimental values. The energy product, evaluated for Nd 2Fe 14B, ranged from ˜224 kJ/m 3 for 10 nm grains to ˜128 kJ/m 3 for 36 nm grains. For grain sizes ⩾20 nm, spatial magnetization variation was confined to domain walls centred on the grain boundaries. For grain sizes decreasing below about twice the domain wall thickness, spatial magnetization variation extended to the interior of the grains and exhibited increasingly long-range correlations.

Decreased lung compliance increases preload dynamic tests in a pediatric acute lung injury model.

PubMed

Erranz, Benjamín; Díaz, Franco; Donoso, Alejandro; Salomón, Tatiana; Carvajal, Cristóbal; Torres, María Fernanda; Cruces, Pablo

2015-01-01

Preload dynamic tests, pulse pressure variation (PPV) and stroke volume variation (SVV) have emerged as powerful tools to predict response to fluid administration. The influence of factors other than preload in dynamic preload test is currently poorly understood in pediatrics. The aim of our study was to assess the effect of tidal volume (VT) on PPV and SVV in the context of normal and reduced lung compliance in a piglet model. Twenty large-white piglets (5.2±0.4kg) were anesthetized, paralyzed and monitored with pulse contour analysis. PPV and SVV were recorded during mechanical ventilation with a VT of 6 and 12mL/kg (low and high VT, respectively), both before and after tracheal instillation of polysorbate 20. Before acute lung injury (ALI) induction, modifications of VT did not significantly change PPV and SVV readings. After ALI, PPV and SVV were significantly greater during ventilation with a high VT compared to a low VT (PPV increased from 8.9±1.2 to 12.4±1.1%, and SVV from 8.5±1.0 to 12.7±1.2%, both P<0.01). This study found that a high VT and reduced lung compliance due to ALI increase preload dynamic tests, with a greater influence of the latter. In subjects with ALI, lung compliance should be considered when interpreting the preload dynamic tests. Copyright © 2015 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Regional and temporal variation in minor ions in groundwater of a part of a large river delta, southern India.

PubMed

Elumalai, Vetrimurugan; Brindha, K; Elango, L

2017-07-01

Impact of agricultural activities on groundwater can be determined from the concentration of nutrients present in groundwater. This study was carried out with the aim to assess the minor ions content of groundwater and to identify its sources, spatial, and seasonal variations in a part of the Cauvery River basin, southern India. Groundwater samples were collected from July 2007 to September 2009 and were analyzed for minor ions. These ions were in the order of dominance of nitrate> phosphate> bromide> fluoride> ammonium= nitrite> lithium. The concentration of ions tends to increase towards the coast except for fluoride. Increased concentration of ions identified in shallow wells than in deep wells with an exception of few locations indicates the impact of human activities. Relatively high concentration of agriculture-sourced nitrate was identified which pose a threat to groundwater suitability for agriculture and domestic usage. Combined influence of use of agrochemicals, improper sewage disposal, aquaculture activities, seawater intrusion due to heavy pumping near the coast, and natural weathering of aquifer materials are the major sources. Also, fine grain sediments of this area aid in poor flushing of the ions towards the sea resulting in accumulation of higher concentration of ions. A sustainable management strategy is essential to control the concentration of these ions, especially nitrate. Reduced use of fertilizers, increasing the rainfall recharge for diluting the pollutants in groundwater and maintaining the river flow for sufficiently longer period to reduce dependence on groundwater for irrigation can help to improve the situation.

Differential Roles for the Thyroarytenoid and Lateral Cricoarytenoid Muscles in Phonation

PubMed Central

Chhetri, Dinesh K.; Neubauer, Juergen

2015-01-01

Objective Laryngeal adductor muscle dysfunction is common cause of voice disorders. Reconstitution of adductor muscle function is often the target of therapy, but the effects of these muscles on voice production remain to be fully understood. This study investigated the differential roles of thyroarytenoid (TA) and lateral cricoarytenoid (LCA) muscles on voice production. Study Design Basic science study using an in vivo canine model of phonation. Methods The TA and LCA muscle nerve branches were stimulated to obtain 7 graded levels of muscle activation, from threshold to maximal contraction. The effects of LCA activation alone, TA activation alone, and combined TA and LCA activation on phonation onset parameters were investigated. Phonatory posture, phonation onset type, fundamental frequency (F0), phonation onset pressure, and airflow were evaluated. Results LCA activation closed the posterior glottis but mid-membranous gap remained. TA activation closed the membranous glottis but posterior gap remained. Complete glottal closure was obtained only with combined TA and LCA activation. Phonation onset with LCAs alone was characterized by multiple modes (soft, aperiodic, periodic), while with TAs alone was abrupt and periodic but had significant baseline noise. Combined muscle activation led to elimination of baseline noise with stable abrupt periodic onset of phonation. Combined muscle activation was also necessary for F0 variation. LCA assisted the TA in increasing subglottal pressure while concurrently reducing phonation onset airflow. Conclusion TA is necessary for F0 variation, stable onset phonation, and increased subglottal pressure but needs LCA for optimal effectiveness and to reduce airflow requirements with increased activation. PMID:26198167

Prevalence of quinolone resistance genes, copper resistance genes, and the bacterial communities in a soil-ryegrass system co-polluted with copper and ciprofloxacin.

PubMed

Tuo, Xiaxia; Gu, Jie; Wang, Xiaojuan; Sun, YiXin; Duan, Manli; Sun, Wei; Yin, Yanan; Guo, Aiyun; Zhang, Li

2018-04-01

The presence of high concentrations of residual antibiotics and antibiotic resistance genes (ARGs) in soil may pose potential health and environmental risks. This study investigated the prevalence of plasmid-mediated quinolone resistance (PMQR) genes, copper resistance genes (CRGs), and the bacterial communities in a soil-ryegrass pot system co-polluted with copper and ciprofloxacin (CIP; 0, 20, or 80 mg kg -1 dry soil). Compared with the samples on day 0, the total relative abundances of the PMQR genes and mobile genetic elements (MGEs) were reduced significantly by 80-89% in the ryegrass and soil by the cutting stage (after 75 days). The abundances of PMQR genes and MGEs were reduced by 63-81% in soil treated with 20 mg kg -1 CIP compared with the other treatments, but the abundances of CRGs increased by 18-42%. The presence of 80 mg kg -1 CIP affected the microbial community structure in the soil by increasing the abundances of Acidobacteria and Thaumarchaeota, but decreasing those of Firmicutes. Redundancy analysis indicated that the pH and microbial composition were the main factors that affected the variations in PMQR genes, MGEs, and CRGs, where they could explain 42.2% and 33.3% of the variation, respectively. Furthermore, intI2 may play an important role in the transfer of ARGs. We found that 80 mg kg -1 CIP could increase the abundances of ARGs and CRGs in a soil-ryegrass pot system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Anomalous droughts, not invasion, decrease persistence of native fishes in a desert river.

PubMed

Ruhí, Albert; Holmes, Elizabeth E; Rinne, John N; Sabo, John L

2015-04-01

Changing climate extremes and invasion by non-native species are two of the most prominent threats to native faunas. Predicting the relationships between global change and native faunas requires a quantitative toolkit that effectively links the timing and magnitude of extreme events to variation in species abundances. Here, we examine how discharge anomalies--unexpected floods and droughts--determine covariation in abundance of native and non-native fish species in a highly variable desert river in Arizona. We quantified stochastic variation in discharge using Fourier analyses on >15,000 daily observations. We subsequently coupled maximum annual spectral anomalies with a 15-year time series of fish abundances (1994-2008), using Multivariate Autoregressive State-Space (MARSS) models. Abiotic drivers (discharge anomalies) were paramount in determining long-term fish abundances, whereas biotic drivers (species interactions) played only a secondary role. As predicted, anomalous droughts reduced the abundances of native species, while floods increased them. However, in contrast to previous studies, we observed that the non-native assemblage was surprisingly unresponsive to extreme events. Biological trait analyses showed that functional uniqueness was higher in native than in non-native fishes. We also found that discharge anomalies influenced diversity patterns at the meta-community level, with nestedness increasing after anomalous droughts due to the differential impairment of native species. Overall, our results advance the notion that discharge variation is key in determining community trajectories in the long term, predicting the persistence of native fauna even in the face of invasion. We suggest this variation, rather than biotic interactions, may commonly underlie covariation between native and non-native faunas, especially in highly variable environments. If droughts become increasingly severe due to climate change, and floods increasingly muted due to regulation, fish assemblages in desert rivers may become taxonomically and functionally impoverished and dominated by non-native taxa. © 2014 John Wiley & Sons Ltd.

Evaluating the Influence of Solar Radiation, Coral Extension Rate and Anthropogenic CO2 on Skeletal δ13C in a Network of Fiji and Tonga Porites Corals

NASA Astrophysics Data System (ADS)

Dassie, E. P.; Lemley, G. M.; Linsley, B. K.; Howe, S. S.

2011-12-01

While stable oxygen isotope signatures in coral reefs have proven to be reliable recorders of temperature and salinity, it is difficult to interpret their skeletal 13C/12C signatures. Various studies have suggested that coral skeletal δ13C is primarily controlled by complex physiological mechanisms. However, it has also been proposed that δ13C variations in coral skeletons are related to more apparent factors such as solar radiation, skeletal extension rate, and the anthropogenic addition of 13C-depleted CO2 into the atmosphere and surface ocean ("Suess Effect"). We will present time-series variations of δ13C in six coral cores from Fiji and Tonga (South Pacific Ocean). On seasonal timescales, increases in solar radiation are correlated to increases in skeletal δ13C and visa-versa. Annually averaged data shows a correlation between increased coral δ13C and reduced coral extension rate, while a decrease in δ13C is associated with an increased extension rate. In the most recent portion of four of the coral δ13C records (from around 1900 to the core top), the value progressively decreases - a trend that is not present in either the skeletal extension rate or solar radiation data. We conclude that this decreasing δ13C trend is a consequence of the Suess Effect, as reported in other coral δ13C records. However, two of the six corals do not show this decreasing trend, which may be a result of their residence in especially shallow water (sub-tidal environments). The onset of the Suess effect in the four corals may help constrain the timing of the uptake of anthropogenic carbon by the western South Pacific Ocean. Although all factors controlling δ13C variation in corals are not completely understood, this study works towards an understanding of their relative contribution to δ13C variation.

Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin

USGS Publications Warehouse

O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G.

2012-01-01

Soil beneath a stormwater infiltration basin receiving runoff from a 22.7 ha predominantly residential watershed in central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop a prototype stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO3-/Cl-) ratios for the shallow groundwater indicate that prior to using BAM, NO3- concentrations were substantially influenced by nitrification or variations in NO3- input. In contrast, for the prototype basin utilizing BAM, NO3-/Cl- ratios indicate minor nitrification and NO3- losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest NO3- losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO43-) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO43-/Cl- ratios for shallow groundwater indicate predominantly minor increases and decreases in PO43- with the exception of one summer sample that indicated a 50% loss. Differences in nutrient variations between the unsaturated zone and shallow groundwater may be the result of the intensity and duration of nutrient removal processes and mixing ratios with water that had not undergone significant chemical changes. Observed nitrogen and phosphorus losses demonstrate the potential, as well as future research needs to improve performance, of the prototype stormwater infiltration basin using BAM for providing passive, economical, stormwater nutrient-treatment technology to support green infrastructure.

[Variation trends of the vegetations in distribution region of Amur tiger based on MODIS NDVI].

PubMed

Wang, Hua-Ru; Wang, Tian-Ming; Ge, Han-Ping

2012-10-01

By using the averaged 250 m MODIS NDVI data in growth seasons of 2000-2010 and the approach of ordinary linear regression, this paper analyzed the variation trends of the vegetations in the distribution region of Amur tiger (Panthera tigris altaica), the Far East region of Russia and the eastern part of Northeast China, as well as the relationships between these variation trends and the anthropogenic activities. In 2000 - 2010, the areas with significantly decreased NDVI were sparsely distributed and accounted for 9.6% of the total, while the areas with significantly increased NDVI were mainly concentrated in the central part of northern Russia Far East Region and only accounted for 0.5% of the total. The percentage of the areas with significantly decreased NDVI in the distribution region of Amur tiger was slightly higher than that in the whole study region. The areas with significantly decreased NDVI were mainly distributed in the places of low elevation, gentle slope, and close to roads/railroads. The number of the pixels with significantly decreased NDVI increased with the increase of the nearest distance to residential locations first, and then decreased gradually. The significant decrease of the NDVI was closely related to the anthropogenic activities, and thus, to adopt effective measures to reduce human disturbances could control the vegetation degradation, and further, provide sustainable basis for the protection of Amur tiger and the conservation of the biodiversity in the studied region.

A methodology for probabilistic remaining creep life assessment of gas turbine components

NASA Astrophysics Data System (ADS)

Liu, Zhimin

Certain gas turbine components operate in harsh environments and various mechanisms may lead to component failure. It is common practice to use remaining life assessments to help operators schedule maintenance and component replacements. Creep is a major failure mechanisms that affect the remaining life assessment, and the resulting life consumption of a component is highly sensitive to variations in the material stresses and temperatures, which fluctuate significantly due to the changes in real operating conditions. In addition, variations in material properties and geometry will result in changes in creep life consumption rate. The traditional method used for remaining life assessment assumes a set of fixed operating conditions at all times, and it fails to capture the variations in operating conditions. This translates into a significant loss of accuracy and unnecessary high maintenance and replacement cost. A new method that captures these variations described above and improves the prediction accuracy of remaining life is developed. First, a metamodel is built to approximate the relationship between variables (operating conditions, material properties, geometry, etc.) and a creep response. The metamodel is developed using Response Surface Method/Design of Experiments methodology. Design of Experiments is an efficient sampling method, and for each sampling point a set of finite element analyses are used to compute the corresponding response value. Next, a low order polynomial Response Surface Equation (RSE) is used to fit these values. Four techniques are suggested to dramatically reduce computational effort, and to increase the accuracy of the RSE: smart meshing technique, automatic geometry parameterization, screening test and regional RSE refinement. The RSEs, along with a probabilistic method and a life fraction model are used to compute current damage accumulation and remaining life. By capturing the variations mentioned above, the new method results in much better accuracy than that available using the traditional method. After further development and proper verification the method should bring significant savings by reducing the number of inspections and deferring part replacement.

Amygdala Volume in Offspring from Multiplex for Alcohol Dependence Families: The Moderating Influence of Childhood Environment and 5-HTTLPR Variation.

PubMed

Hill, Shirley Y; Wang, Shuhui; Carter, Howard; McDermott, Michael D; Zezza, Nicholas; Stiffler, Scott

2013-12-12

The increased susceptibility for developing alcohol dependence seen in offspring from families with alcohol dependence may be related to structural and functional differences in brain circuits that influence emotional processing. Early childhood environment, genetic variation in the serotonin transporter-linked polymorphic region (5-HTTLPR) of the SLCA4 gene and allelic variation in the Brain Derived Neurotrophic Factor (BDNF) gene have each been reported to be related to volumetric differences in the temporal lobe especially the amygdala. Magnetic resonance imaging was used to obtain amygdala volumes for 129 adolescent/young adult individuals who were either High-Risk (HR) offspring from families with multiple cases of alcohol dependence (N=71) or Low-Risk (LR) controls (N=58). Childhood family environment was measured prospectively using age-appropriate versions of the Family Environment Scale during a longitudinal follow-up study. The subjects were genotyped for Brain-Derived Neurotrophic Factor (BDNF) Val66Met and the serotonin transporter polymorphism (5-HTTLPR). Two family environment scale scores (Cohesion and Conflict), genotypic variation, and their interaction were tested for their association with amygdala volumes. Personal and prenatal exposure to alcohol and drugs were considered in statistical analyses in order to more accurately determine the effects of familial risk group differences. Amygdala volume was reduced in offspring from families with multiple alcohol dependent members in comparison to offspring from control families. High-Risk offspring who were carriers of the S variant of the 5-HTTLPR polymorphism had reduced amygdala volume in comparison to those with an LL genotype. Larger amygdala volume was associated with greater family cohesion but only in Low-Risk control offspring. Familial risk for alcohol dependence is an important predictor of amygdala volume even when removing cases with significant personal exposure and covarying for prenatal exposure effects. The present study provides new evidence that amygdala volume is modified by 5-HTTLPR variation in High-Risk families.

Variation in Sulfur and Selenium Accumulation Is Controlled by Naturally Occurring Isoforms of the Key Sulfur Assimilation Enzyme ADENOSINE 5′-PHOSPHOSULFATE REDUCTASE2 across the Arabidopsis Species Range1[W][OPEN

PubMed Central

Chao, Dai-Yin; Baraniecka, Patrycja; Danku, John; Koprivova, Anna; Lahner, Brett; Luo, Hongbing; Yakubova, Elena; Dilkes, Brian; Kopriva, Stanislav; Salt, David E.

2014-01-01

Natural variation allows the investigation of both the fundamental functions of genes and their role in local adaptation. As one of the essential macronutrients, sulfur is vital for plant growth and development and also for crop yield and quality. Selenium and sulfur are assimilated by the same process, and although plants do not require selenium, plant-based selenium is an important source of this essential element for animals. Here, we report the use of linkage mapping in synthetic F2 populations and complementation to investigate the genetic architecture of variation in total leaf sulfur and selenium concentrations in a diverse set of Arabidopsis (Arabidopsis thaliana) accessions. We identify in accessions collected from Sweden and the Czech Republic two variants of the enzyme ADENOSINE 5′-PHOSPHOSULFATE REDUCTASE2 (APR2) with strongly diminished catalytic capacity. APR2 is a key enzyme in both sulfate and selenate reduction, and its reduced activity in the loss-of-function allele apr2-1 and the two Arabidopsis accessions Hodonín and Shahdara leads to a lowering of sulfur flux from sulfate into the reduced sulfur compounds, cysteine and glutathione, and into proteins, concomitant with an increase in the accumulation of sulfate in leaves. We conclude from our observation, and the previously identified weak allele of APR2 from the Shahdara accession collected in Tadjikistan, that the catalytic capacity of APR2 varies by 4 orders of magnitude across the Arabidopsis species range, driving significant differences in sulfur and selenium metabolism. The selective benefit, if any, of this large variation remains to be explored. PMID:25245030

On the influence of Aerosols in measurement of electric field from Earth surface using a Field-Mill

NASA Astrophysics Data System (ADS)

Ghosh, Abhijit; Sundar De, Syam; Paul, Suman; Hazra, Pranab; Guha, Gautam

2016-07-01

Aerosol particles influence the electrical conductivity of air. The value is reduced through the removal of small ions responsible for the conductivity. The metropolitan city, Kolkata (latitude 22.56° N, longitude 88.5° E) is densely populated surrounded by various types of Industries. Air is highly invaded by pollutant particles here for which the city falls under small-scale fair-weather condition where electric field and air-earth current get perturbed by ionization and different aerosols produced locally. Fine particles having diameter < 0.1 μm (Aitken nuclei) are distributed in air which decreases the electrical conductivity and increases the columnar resistance. Aerosol particles steadily change the status at different times of the day through coagulation, sedimentation, charge-transfer initiated by precipitation. The diurnal variation of potential gradient is caused mainly due to urbanization, emission from industry and traffic. The rate of production of haze (atmospheric suspension) and their vertical transportation control the daily variation of atmospheric potential. The nuclei of pollutant particles combine with ions and decrease the concentration of small ions thereby reducing the conductivity. The pollutants, influenced by CO _{2} and other green house gas emission from fossil fuels are also responsible for the variation of electric field. Variation in consumption of Oil and Gasoline due to traffic in the city contributes a high Aitken count and there are changes in atmospheric dispersion following reduction of conductivity of the medium. Outcome of some important measurement of potential gradient and air-earth current will be presented. Different parameters like air-conductivity, relative abundance of smoke, visibility would offer new signatures of aerosol-influence on electric potential gradient. Some of those will be reported here.

Within-summer variation in out-of-hospital cardiac arrest due to extremely long sunshine duration.

PubMed

Onozuka, Daisuke; Hagihara, Akihito

2017-03-15

Although several studies have reported the impacts of extremely high temperatures on cardiovascular diseases, no studies have examined whether variation in out-of-hospital cardiac arrest (OHCA) due to extremely long sunshine duration changes during the summer. We obtained daily data on all cases of OHCA and weather variations for all 47 prefectures of Japan during the summer (June to September) between 2005 and 2014. A distributed lag non-linear model combined with a quasi-Poisson regression model was used to estimate within-summer variation in OHCA due to extremely long sunshine duration for each prefecture. Then, multivariate random-effects meta-analysis was performed to derive overall effect estimates of sunshine duration at the national level. A total of 166,496 OHCAs of presumed cardiac origin met the inclusion criteria. The minimum morbidity percentile (MMP) was the 0th percentile of sunshine duration at the national level. The overall cumulative relative risk (RR) at the 99th percentile vs. the MMP was 1.15 (95% CI: 1.05-1.27) during the summer. The effect of extremely long sunshine duration on OHCA in early summer was acute and did not persist, whereas an identical effect was observed in late summer, but it was delayed and lasted for several days. During summer periods, excessive sunshine duration could increase the risk of OHCA. Timely preventive measures to reduce the OHCA risk due to extremely long sunshine duration are important in early summer, whereas these measures could include a wider time window of several days to reduce the risk in late summer. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Experimentally reduced root-microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus.

PubMed

Lee, Mei-Ho; Comas, Louise H; Callahan, Hilary S

2014-02-01

Interactions between roots and soil microbes are critical components of below-ground ecology. It is essential to quantify the magnitude of root trait variation both among and within species, including variation due to plasticity. In addition to contextualizing the magnitude of plasticity relative to differences between species, studies of plasticity can ascertain if plasticity is predictable and whether an environmental factor elicits changes in traits that are functionally advantageous. To compare functional traits and trait plasticities in fine root tissues with natural and reduced levels of colonization by microbial symbionts, trimmed and surface-sterilized root segments of 2-year-old Acer rubrum and Quercus rubra seedlings were manipulated. Segments were then replanted into satellite pots filled with control or heat-treated soil, both originally derived from a natural forest. Mycorrhizal colonization was near zero in roots grown in heat-treated soil; roots grown in control soil matched the higher colonization levels observed in unmanipulated root samples collected from field locations. Between-treatment comparisons revealed negligible plasticity for root diameter, branching intensity and nitrogen concentration across both species. Roots from treated soils had decreased tissue density (approx. 10-20 %) and increased specific root length (approx. 10-30 %). In contrast, species differences were significant and greater than treatment effects in traits other than tissue density. Interspecific trait differences were also significant in field samples, which generally resembled greenhouse samples. The combination of experimental and field approaches was useful for contextualizing trait plasticity in comparison with inter- and intra-specific trait variation. Findings that root traits are largely species dependent, with the exception of root tissue density, are discussed in the context of current literature on root trait variation, interactions with symbionts and recent progress in standardization of methods for quantifying root traits.

Familial hypertrophic cardiomyopathy: functional variance among individual cardiomyocytes as a trigger of FHC-phenotype development

PubMed Central

Brenner, Bernhard; Seebohm, Benjamin; Tripathi, Snigdha; Montag, Judith; Kraft, Theresia

2014-01-01

Familial hypertrophic cardiomyopathy (FHC) is the most frequent inherited cardiac disease. It has been related to numerous mutations in many sarcomeric and even some non-sarcomeric proteins. So far, however, no common mechanism has been identified by which the many different mutations in different sarcomeric and non-sarcomeric proteins trigger development of the FHC phenotype. Here we show for different MYH7 mutations variance in force pCa-relations from normal to highly abnormal as a feature common to all mutations we studied, while direct functional effects of the different FHC-mutations, e.g., on force generation, ATPase or calcium sensitivity of the contractile system, can be quite different. The functional variation among individual M. soleus fibers of FHC-patients is accompanied by large variation in mutant vs. wildtype β-MyHC-mRNA. Preliminary results show a similar variation in mutant vs. wildtype β-MyHC-mRNA among individual cardiomyocytes. We discuss our previously proposed concept as to how different mutations in the β-MyHC and possibly other sarcomeric and non-sarcomeric proteins may initiate an FHC-phenotype by functional variation among individual cardiomyocytes that results in structural distortions within the myocardium, leading to cellular and myofibrillar disarray. In addition, distortions can activate stretch-sensitive signaling in cardiomyocytes and non-myocyte cells which is known to induce cardiac remodeling with interstitial fibrosis and hypertrophy. Such a mechanism will have major implications for therapeutic strategies to prevent FHC-development, e.g., by reducing functional imbalances among individual cardiomyocytes or by inhibition of their triggering of signaling paths initiating remodeling. Targeting increased or decreased contractile function would require selective targeting of mutant or wildtype protein to reduce functional imbalances. PMID:25346696