Science.gov

Sample records for influence fitness variation

  1. Predation risk and longevity influence variation in fitness of female roe deer (Capreolus capreolus L.).

    PubMed Central

    Kjellander, Petter; Gaillard, Jean-Michel; Hewison, Mark; Liberg, Olof

    2004-01-01

    We studied the effects of population density, red fox predation risk, individual body mass and longevity on female fitness in a free-ranging roe deer population. During the study, population density varied from 9.3 to 36.1 deer km(-2), and red fox abundance varied strongly over years owing to a sarcoptic mange outbreak. In support of our predictions, long-lived females had higher fitness than short-lived ones. Further, fortunate female roe deer that gave birth in years of low red fox abundance attained much higher fitness than those that gave birth in years of high red fox abundance. Longevity and predation risk explained more than half the variation in fitness observed among roe deer females. As a possible effect of small sample size, we found no effect of female body mass or population density at birth. Our study demonstrates that predation risk, a component of environmental stochasticity, may prevent directional selection even when phenotypic quality influences individual fitness. PMID:15504011

  2. Seasonal temperature variations influence tapetum mitosis patterns associated with reproductive fitness.

    PubMed

    Lavania, Umesh C; Basu, Surochita; Kushwaha, Jyotsana Singh; Lavania, Seshu

    2014-09-01

    Environmental stress in plants impacts many biological processes, including male gametogenesis, and affects several cytological mechanisms that are strongly interrelated. To understand the likely impact of rising temperature on reproductive fitness in the climate change regime, a study of tapetal mitosis and its accompanying meiosis over seasons was made to elucidate the influence of temperature change on the cytological events occurring during microsporogenesis. For this we used two species of an environmentally sensitive plant system, i.e., genus Cymbopogon Sprengel (Poaceae), namely Cymbopogon nardus (L.) Rendle var. confertiflorus (Steud.) Bor (2n = 20) and Cymbopogon jwaruncusha (Jones) Schult. (2n = 20). Both species flower profusely during extreme summer (48 °C) and mild winter (15 °C) but support low and high seed fertility, respectively, in the two seasons. We have shown that tapetal mitotic patterns over seasons entail differential behavior for tapetal mitosis. During the process of tapetum development there are episodes of endomitosis that form either (i) an endopolyploid genomically imbalanced uninucleate and multinucleate tapetum, and (or) (ii) an acytokinetic multinucleate genomically balanced tapetum, with the progression of meiosis in the accompanying sporogenous tissue. The relative frequency of occurrence of the two types of tapetum mitosis patterns is significantly different in the two seasons, and it is found to be correlated with the temperature conditions. Whereas, the former (genomically imbalanced tapetum) are prevalent during the hot summer, the latter (genomically balanced tapetum) are frequent under optimal conditions. Such a differential behaviour in tapetal mitosis vis-à-vis temperature change is also correspondingly accompanied by substantial disturbances or regularity in meiotic anaphase disjunction. Both species show similar patterns. The study underpins that tapetal mitotic behaviour per se could be a reasonable indicator to

  3. Fitness implications of seasonal climate variation in Columbian ground squirrels.

    PubMed

    Dobson, F Stephen; Lane, Jeffrey E; Low, Matthew; Murie, Jan O

    2016-08-01

    The influence of climate change on the fitness of wild populations is often studied in the context of the spring onset of the reproductive season. This focus is relevant for climate influences on reproductive success, but neglects other fitness-relevant periods (e.g., autumn preparation for overwintering). We examined variation in climate variables (temperature, rainfall, snowfall, and snowpack) across the full annual cycle of Columbian ground squirrels (Urocitellus columbianus) for 21 years. We investigated seasonal climate variables that were associated with fitness variables, climate variables that exhibited directional changes across the study period, and finally observed declines in fitness (-0.03 units/year; total decline = 37%) that were associated with directional changes in climate variables. Annual fitness of adult female ground squirrels was positively associated with spring temperature (r = 0.69) and early summer rainfall (r = 0.56) and negatively associated with spring snow conditions (r = -0.44 to -0.66). Across the 21 years, spring snowmelt has become significantly delayed (r = 0.48) and summer rainfall became significantly reduced (r = -0.53). Using a standardized partial regression model, we found that directional changes in the timing of spring snowmelt and early summer rainfall (i.e., progressively drier summers) had moderate influences on annual fitness, with the latter statistically significant (ρ = -0.314 and 0.437, respectively). The summer period corresponds to prehibernation fattening of young and adult ground squirrels. Had we focused on a single point in time (viz. the onset of the breeding season), we would have underestimated the influences of climate change on our population. Rather, we obtained a comprehensive understanding of the influences of climate change on individual fitness by investigating the full lifecycle. PMID:27547341

  4. Fitness implications of seasonal climate variation in Columbian ground squirrels.

    PubMed

    Dobson, F Stephen; Lane, Jeffrey E; Low, Matthew; Murie, Jan O

    2016-08-01

    The influence of climate change on the fitness of wild populations is often studied in the context of the spring onset of the reproductive season. This focus is relevant for climate influences on reproductive success, but neglects other fitness-relevant periods (e.g., autumn preparation for overwintering). We examined variation in climate variables (temperature, rainfall, snowfall, and snowpack) across the full annual cycle of Columbian ground squirrels (Urocitellus columbianus) for 21 years. We investigated seasonal climate variables that were associated with fitness variables, climate variables that exhibited directional changes across the study period, and finally observed declines in fitness (-0.03 units/year; total decline = 37%) that were associated with directional changes in climate variables. Annual fitness of adult female ground squirrels was positively associated with spring temperature (r = 0.69) and early summer rainfall (r = 0.56) and negatively associated with spring snow conditions (r = -0.44 to -0.66). Across the 21 years, spring snowmelt has become significantly delayed (r = 0.48) and summer rainfall became significantly reduced (r = -0.53). Using a standardized partial regression model, we found that directional changes in the timing of spring snowmelt and early summer rainfall (i.e., progressively drier summers) had moderate influences on annual fitness, with the latter statistically significant (ρ = -0.314 and 0.437, respectively). The summer period corresponds to prehibernation fattening of young and adult ground squirrels. Had we focused on a single point in time (viz. the onset of the breeding season), we would have underestimated the influences of climate change on our population. Rather, we obtained a comprehensive understanding of the influences of climate change on individual fitness by investigating the full lifecycle.

  5. Factors Influencing Physical Fitness Evaluation.

    ERIC Educational Resources Information Center

    Haarer, Barbara G.

    This annotated bibliography focuses on works that examine areas in which the physical educator can improve the administration of physical fitness tests in the elementary and secondary schools. The first part contains annotations that examine modifications of existing components which measure aspects of muscular and cardiovascular endurance. The…

  6. Variationally fitting the total electron-electron interaction

    NASA Astrophysics Data System (ADS)

    Dunlap, Brett I.; Palenik, Mark C.

    2016-05-01

    Density fitting is used throughout quantum chemistry to simplify the electron-electron interaction energy (EE). A fundamental property of quantum chemistry, and DFT in particular, is that a variational principle connects the EE to a potential. Density fitting generally does not preserve this connection. Herein we describe the construction of a robust EE that is variationally connected to fitted potentials in all electronic structure methods. For DFT, this results in fitting equations that are satisfied at an energy saddle point in multidimensional fitting space.

  7. Social and genetic interactions drive fitness variation in a free-living dolphin population

    PubMed Central

    Frère, Celine H.; Krützen, Michael; Mann, Janet; Connor, Richard C.; Bejder, Lars; Sherwin, William B.

    2010-01-01

    The evolutionary forces that drive fitness variation in species are of considerable interest. Despite this, the relative importance and interactions of genetic and social factors involved in the evolution of fitness traits in wild mammalian populations are largely unknown. To date, a few studies have demonstrated that fitness might be influenced by either social factors or genes in natural populations, but none have explored how the combined effect of social and genetic parameters might interact to influence fitness. Drawing from a long-term study of wild bottlenose dolphins in the eastern gulf of Shark Bay, Western Australia, we present a unique approach to understanding these interactions. Our study shows that female calving success depends on both genetic inheritance and social bonds. Moreover, we demonstrate that interactions between social and genetic factors also influence female fitness. Therefore, our study represents a major methodological advance, and provides critical insights into the interplay of genetic and social parameters of fitness. PMID:21041638

  8. Eat fit. Get big? How fitness cues influence food consumption volumes.

    PubMed

    Koenigstorfer, Joerg; Groeppel-Klein, Andrea; Kettenbaum, Myriam; Klicker, Kristina

    2013-06-01

    Fitness cues on food packages are a common marketing practice in the food sector. This study aims to find out whether and how fitness cues influence food consumption. The results of two field studies show that, even though eating fitness-cued food does not help consumers become more fit, the claims on the packaging increase both serving size and actual food consumption. This effect is mediated by serving size inferences. Also, consumers feel less guilty and perceive themselves closer to desired fitness levels after having consumed the food. The findings show that packaging cues relating to energy expenditure can increase energy intake despite the fact that consumers are not engaged in any actual physical activity while eating the food.

  9. Fitness

    MedlinePlus

    ... gov home http://www.girlshealth.gov/ Home Fitness Fitness Want to look and feel your best? Physical ... are? Check out this info: What is physical fitness? top Physical fitness means you can do everyday ...

  10. Ecological Influences on Teachers' Well-Being and "Fitness"

    ERIC Educational Resources Information Center

    Price, Deborah; McCallum, Faye

    2015-01-01

    The complex and ever-changing nature of teachers' work challenges their well-being. Teacher well-being and "fitness" includes versatility, mental strength, and commitment to promote effective teaching and learning. In framing this notion, we seek to understand the ecological influences impacting on teacher well-being and…

  11. Fitness landscapes among many options under social influence.

    PubMed

    Caiado, Camila C S; Brock, William A; Bentley, R Alexander; O'Brien, Michael J

    2016-09-21

    Cultural learning represents a novel problem in that an optimal decision depends not only on intrinsic utility of the decision/behavior but also on transparency of costs and benefits, the degree of social versus individual learning, and the relative popularity of each possible choice in a population. In terms of a fitness-landscape function, this recursive relationship means that multiple equilibria can exist. Here we use discrete-choice theory to construct a fitness-landscape function for a bi-axial decision-making map that plots the magnitude of social influence in the learning process against the costs and payoffs of decisions. Specifically, we use econometric and statistical methods to estimate not only the fitness function but also movements along the map axes. To search for these equilibria, we employ a hill-climbing algorithm that leads to the expected values of optimal decisions, which we define as peaks on the fitness landscape. We illustrate how estimation of a measure of transparency, a measure of social influence, and the associated fitness landscape can be accomplished using panel data sets. PMID:26851173

  12. Fitness landscapes among many options under social influence.

    PubMed

    Caiado, Camila C S; Brock, William A; Bentley, R Alexander; O'Brien, Michael J

    2016-09-21

    Cultural learning represents a novel problem in that an optimal decision depends not only on intrinsic utility of the decision/behavior but also on transparency of costs and benefits, the degree of social versus individual learning, and the relative popularity of each possible choice in a population. In terms of a fitness-landscape function, this recursive relationship means that multiple equilibria can exist. Here we use discrete-choice theory to construct a fitness-landscape function for a bi-axial decision-making map that plots the magnitude of social influence in the learning process against the costs and payoffs of decisions. Specifically, we use econometric and statistical methods to estimate not only the fitness function but also movements along the map axes. To search for these equilibria, we employ a hill-climbing algorithm that leads to the expected values of optimal decisions, which we define as peaks on the fitness landscape. We illustrate how estimation of a measure of transparency, a measure of social influence, and the associated fitness landscape can be accomplished using panel data sets.

  13. Differential responses to thermal variation between fitness metrics.

    PubMed

    Clavijo-Baquet, Sabrina; Boher, Francisca; Ziegler, Lucia; Martel, Sebastián I; Estay, Sergio A; Bozinovic, Francisco

    2014-01-01

    Temperature is a major factor affecting population abundance and individual performance. Net reproductive rate (R0) and intrinsic rate of increase (r) differ in their response to different temperature regimes, and much of the difference is mediated by generation time (Tg). Here, we evaluate the effects of thermal mean and variability on R0, r and Tg, at four population densities in Drosophila melanogaster. The results show that R0, r and Tg present differential responses to thermal variation. Although temperature effects on R0 and Tg are non-linear, r response was negligible. R0 and Tg comprise a generational time scale, while r is at a chronological time scale. Thus, we argue that individuals growing under different thermal environments perform similarly on a chronological scale, but differently on a generational scale. PMID:24954717

  14. Low Demographic Variability in Wild Primate Populations: Fitness Impacts of Variation, Covariation, and Serial Correlation in Vital Rates

    PubMed Central

    Morris, William F.; Altmann, Jeanne; Brockman, Diane K.; Cords, Marina; Fedigan, Linda M.; Pusey, Anne E.; Stoinski, Tara S.; Bronikowski, Anne M.; Alberts, Susan C.; Strier, Karen B.

    2013-01-01

    In a stochastic environment, long-term fitness can be influenced by variation, covariation, and serial correlation in vital rates (survival and fertility). Yet no study of an animal population has parsed the contributions of these three aspects of variability to long-term fitness. We do so using a unique database that includes complete life-history information for wild-living individuals of seven primate species that have been the subjects of long-term (22–45 years) behavioral studies. Overall, the estimated levels of vital rate variation had only minor effects on long-term fitness, and the effects of vital rate covariation and serial correlation were even weaker. To explore why, we compared estimated variances of adult survival in primates with values for other vertebrates in the literature and found that adult survival is significantly less variable in primates than it is in the other vertebrates. Finally, we tested the prediction that adult survival, because it more strongly influences fitness in a constant environment, will be less variable than newborn survival, and we found only mixed support for the prediction. Our results suggest that wild primates may be buffered against detrimental fitness effects of environmental stochasticity by their highly developed cognitive abilities, social networks, and broad, flexible diets. PMID:21117962

  15. Causes of natural variation in fitness: evidence from studies of Drosophila populations.

    PubMed

    Charlesworth, Brian

    2015-02-10

    DNA sequencing has revealed high levels of variability within most species. Statistical methods based on population genetics theory have been applied to the resulting data and suggest that most mutations affecting functionally important sequences are deleterious but subject to very weak selection. Quantitative genetic studies have provided information on the extent of genetic variation within populations in traits related to fitness and the rate at which variability in these traits arises by mutation. This paper attempts to combine the available information from applications of the two approaches to populations of the fruitfly Drosophila in order to estimate some important parameters of genetic variation, using a simple population genetics model of mutational effects on fitness components. Analyses based on this model suggest the existence of a class of mutations with much larger fitness effects than those inferred from sequence variability and that contribute most of the standing variation in fitness within a population caused by the input of mildly deleterious mutations. However, deleterious mutations explain only part of this standing variation, and other processes such as balancing selection appear to make a large contribution to genetic variation in fitness components in Drosophila.

  16. Causes of natural variation in fitness: Evidence from studies of Drosophila populations

    PubMed Central

    Charlesworth, Brian

    2015-01-01

    DNA sequencing has revealed high levels of variability within most species. Statistical methods based on population genetics theory have been applied to the resulting data and suggest that most mutations affecting functionally important sequences are deleterious but subject to very weak selection. Quantitative genetic studies have provided information on the extent of genetic variation within populations in traits related to fitness and the rate at which variability in these traits arises by mutation. This paper attempts to combine the available information from applications of the two approaches to populations of the fruitfly Drosophila in order to estimate some important parameters of genetic variation, using a simple population genetics model of mutational effects on fitness components. Analyses based on this model suggest the existence of a class of mutations with much larger fitness effects than those inferred from sequence variability and that contribute most of the standing variation in fitness within a population caused by the input of mildly deleterious mutations. However, deleterious mutations explain only part of this standing variation, and other processes such as balancing selection appear to make a large contribution to genetic variation in fitness components in Drosophila. PMID:25572964

  17. Age-specific fitness components and their temporal variation in the barn owl.

    PubMed

    Altwegg, Res; Schaub, Michael; Roulin, Alexandre

    2007-01-01

    Theory predicts that temporal variability plays an important role in the evolution of life histories, but empirical studies evaluating this prediction are rare. In constant environments, fitness can be measured by the population growth rate lambda, and the sensitivity of lambda to changes in fitness components estimates selection on these traits. In variable environments, fitness is measured by the stochastic growth rate lambda(S), and stochastic sensitivities estimate selection pressure. Here we examine age-specific schedules for reproduction and survival in a barn owl population (Tyto alba). We estimated how temporal variability affected fitness and selection, accounting for sampling variance. Despite large sample sizes of old individuals, we found no strong evidence for senescence. The most variable fitness components were associated with reproduction. Survival was less variable. Stochastic simulations showed that the observed variation decreased fitness by about 30%, but the sensitivities of lambda and lambda(S) to changes in all fitness components were almost equal, suggesting that temporal variation had negligible effects on selection. We obtained these results despite high observed variability in the fitness components and relatively short generation time of the study organism, a situation in which temporal variability should be particularly important for natural selection and early senescence is expected. PMID:17206584

  18. Noise and Epigenetic Inheritance of Single-Cell Division Times Influence Population Fitness.

    PubMed

    Cerulus, Bram; New, Aaron M; Pougach, Ksenia; Verstrepen, Kevin J

    2016-05-01

    The fitness effect of biological noise remains unclear. For example, even within clonal microbial populations, individual cells grow at different speeds. Although it is known that the individuals' mean growth speed can affect population-level fitness, it is unclear how or whether growth speed heterogeneity itself is subject to natural selection. Here, we show that noisy single-cell division times can significantly affect population-level growth rate. Using time-lapse microscopy to measure the division times of thousands of individual S. cerevisiae cells across different genetic and environmental backgrounds, we find that the length of individual cells' division times can vary substantially between clonal individuals and that sublineages often show epigenetic inheritance of division times. By combining these experimental measurements with mathematical modeling, we find that, for a given mean division time, increasing heterogeneity and epigenetic inheritance of division times increases the population growth rate. Furthermore, we demonstrate that the heterogeneity and epigenetic inheritance of single-cell division times can be linked with variation in the expression of catabolic genes. Taken together, our results reveal how a change in noisy single-cell behaviors can directly influence fitness through dynamics that operate independently of effects caused by changes to the mean. These results not only allow a better understanding of microbial fitness but also help to more accurately predict fitness in other clonal populations, such as tumors.

  19. Variation and fitness costs for tolerance to different types of herbivore damage in Boechera stricta genotypes with contrasting glucosinolate structures

    PubMed Central

    Manzaneda, Antonio J.; Prasad, Kasavajhala V. S. K.; Mitchell-Olds, Thomas

    2010-01-01

    Summary Analyses of plant tolerance in response to different modes of herbivory are essential to understand plant defense evolution, yet are still scarce. Allocation costs and trade-offs between tolerance and plant chemical defenses may influence genetic variation for tolerance. However, variation in defenses occurs also for presence or absence of discrete chemical structures, yet, effects of intra-specific polymorphisms on tolerance to multiple herbivores have not been evaluated.Here, in a glasshouse experiment, we investigated variation for tolerance to different types of herbivory damage, and direct allocation costs in 10 genotypes of Boechera stricta (Brassicaceae), a wild relative of Arabidopsis, with contrasting foliar glucosinolate chemical structures (methionine-derived glucosinolates vs glucosinolates derived from branched-chain amino acids).We found significant genetic variation for tolerance to different types of herbivory. Structural variations in the glucosinolate profile did not influence tolerance to damage, but predicted plant fitness. Levels of constitutive and induced glucosinolates varied between genotypes with different structural profiles, but we did not detect any cost of tolerance explaining genetic variation in tolerance among genotypes.Trade-offs among plant tolerance to multiple herbivores may not explain the existence of intermediate levels of tolerance to damage in plants with contrasting chemical defensive profiles. PMID:20663059

  20. Eurofit Special: European Fitness Battery Score Variation among Individuals with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Skowronski, Waldemar; Horvat, Michael; Nocera, Joe; Roswal, Glenn; Croce, Ron

    2009-01-01

    The Eurofit Special Test is a battery of motor fitness tests resulting from a 10-year project of the Committee of Experts for Sports Research and is comprised of strength, speed, flexibility, and balance. The purpose of this study was to investigate whether the Eurofit Special was able to distinguish variations in functioning among individuals…

  1. Natural genetic variation in Arabidopsis thaliana defense metabolism genes modulates field fitness

    PubMed Central

    Kerwin, Rachel; Feusier, Julie; Corwin, Jason; Rubin, Matthew; Lin, Catherine; Muok, Alise; Larson, Brandon; Li, Baohua; Joseph, Bindu; Francisco, Marta; Copeland, Daniel; Weinig, Cynthia; Kliebenstein, Daniel J

    2015-01-01

    Natural populations persist in complex environments, where biotic stressors, such as pathogen and insect communities, fluctuate temporally and spatially. These shifting biotic pressures generate heterogeneous selective forces that can maintain standing natural variation within a species. To directly test if genes containing causal variation for the Arabidopsis thaliana defensive compounds, glucosinolates (GSL) control field fitness and are therefore subject to natural selection, we conducted a multi-year field trial using lines that vary in only specific causal genes. Interestingly, we found that variation in these naturally polymorphic GSL genes affected fitness in each of our environments but the pattern fluctuated such that highly fit genotypes in one trial displayed lower fitness in another and that no GSL genotype or genotypes consistently out-performed the others. This was true both across locations and within the same location across years. These results indicate that environmental heterogeneity may contribute to the maintenance of GSL variation observed within Arabidopsis thaliana. DOI: http://dx.doi.org/10.7554/eLife.05604.001 PMID:25867014

  2. A Segregating Inversion Generates Fitness Variation in Yellow Monkeyflower (Mimulus guttatus).

    PubMed

    Lee, Young Wha; Fishman, Lila; Kelly, John K; Willis, John H

    2016-04-01

    Polymorphic chromosomal rearrangements can bind hundreds of genes into single genetic loci with diverse effects. Rearrangements are often associated with local adaptation and speciation and may also be an important component of genetic variation within populations. We genetically and phenotypically characterize a segregating inversion (inv6) in the Iron Mountain (IM) population of Mimulus guttatus (yellow monkeyflower). We initially mapped inv6 as a region of recombination suppression in three F2 populations resulting from crosses among IM plants. In each case, the F1 parent was heterozygous for a derived haplotype, homogenous across markers spanning over 5 Mb of chromsome 6. In the three F2 populations, inv6 reduced male and female fitness components. In addition,i nv6 carriers suffered an ∼30% loss of pollen viability in the field. Despite these costs, inv6 exists at moderate frequency (∼8%) in the natural population, suggesting counterbalancing fitness benefits that maintain the polymorphism. Across 4 years of monitoring in the field, inv6 had an overall significant positive effect on seed production (lifetime female fitness) of carriers. This benefit was particularly strong in harsh years and may be mediated (in part) by strong positive effects on flower production. These data suggest that opposing fitness effects maintain an intermediate frequency, and as a consequence, inv6 generates inbreeding depression and high genetic variance. We discuss these findings in relation to the theory of inbreeding depression and the maintenance of fitness variation.

  3. Maternal investment mediates offspring life history variation with context-dependent fitness consequences.

    PubMed

    Moore, Michael P; Landberg, Tobias; Whiteman, Howard H

    2015-09-01

    Maternal effects, such as per capita maternal investment, often interact with environmental conditions to strongly affect traits expressed early in ontogeny. However, their impact on adult life history traits and fitness components is relatively unknown. Theory predicts that lower per capita maternal investment will have strong fitness costs when the offspring develop in unfavorable conditions, yet few studies have experimentally manipulated per capita maternal investment and followed offspring through adulthood. We used a surgical embryonic yolk removal technique to investigate how per capita maternal investment interacted with an important ecological factor, larval density, to mediate offspring life history traits through reproductive maturity in an amphibian, Ambystoma talpoideum. We predicted that increased larval density would reinforce the life history variation induced by differences in per capita investment (i.e., Controls vs. Reduced Yolk), with Reduced larvae ultimately expressing traits associated with lower fitness than Controls when raised at high densities. We found that Reduced individuals were initially smaller and more developed, caught up in size to Controls within the first month of the larval stage, but were smaller at the end of the larval stage in low densities. Reduced individuals also were more likely to undergo metamorphosis at high densities and mature 'females invested in more eggs for their body sizes than Controls. Together, our results do not support our hypothesis, but instead indicate that Reduced individuals express traits associated with higher fitness when they develop in high-density environments, but lower fitness in low-density environments. The observed life history and fitness patterns are consistent with the "maternal match" hypothesis, which predicts that when the maternal environment (e.g., high density) results in phenotypic variation that is transmitted to the offspring (e.g., reduced per capita yolk investment), and

  4. Maternal investment mediates offspring life history variation with context-dependent fitness consequences.

    PubMed

    Moore, Michael P; Landberg, Tobias; Whiteman, Howard H

    2015-09-01

    Maternal effects, such as per capita maternal investment, often interact with environmental conditions to strongly affect traits expressed early in ontogeny. However, their impact on adult life history traits and fitness components is relatively unknown. Theory predicts that lower per capita maternal investment will have strong fitness costs when the offspring develop in unfavorable conditions, yet few studies have experimentally manipulated per capita maternal investment and followed offspring through adulthood. We used a surgical embryonic yolk removal technique to investigate how per capita maternal investment interacted with an important ecological factor, larval density, to mediate offspring life history traits through reproductive maturity in an amphibian, Ambystoma talpoideum. We predicted that increased larval density would reinforce the life history variation induced by differences in per capita investment (i.e., Controls vs. Reduced Yolk), with Reduced larvae ultimately expressing traits associated with lower fitness than Controls when raised at high densities. We found that Reduced individuals were initially smaller and more developed, caught up in size to Controls within the first month of the larval stage, but were smaller at the end of the larval stage in low densities. Reduced individuals also were more likely to undergo metamorphosis at high densities and mature 'females invested in more eggs for their body sizes than Controls. Together, our results do not support our hypothesis, but instead indicate that Reduced individuals express traits associated with higher fitness when they develop in high-density environments, but lower fitness in low-density environments. The observed life history and fitness patterns are consistent with the "maternal match" hypothesis, which predicts that when the maternal environment (e.g., high density) results in phenotypic variation that is transmitted to the offspring (e.g., reduced per capita yolk investment), and

  5. Variation in sport participation, fitness and motor coordination with socioeconomic status among Flemish children.

    PubMed

    Vandendriessche, Joric B; Vandorpe, Barbara F R; Vaeyens, Roel; Malina, Robert M; Lefevre, Johan; Lenoir, Matthieu; Philippaerts, Renaat M

    2012-02-01

    Socioeconomic status (SES) is often indicated as a factor that influences physical activity and associated health outcomes. This study examined the relationship between SES and sport participation, morphology, fitness and motor coordination in a sample of 1955 Flemish children 6-11 years of age. Gender, age and SES-specific values for morphologic dimensions, amount and type of sport participation and fitness and motor coordination tests were compared. SES was positively and significantly associated with sport participation and sports club membership in both sexes. Although differences were not consistently significant, morphologic dimensions and tests of fitness and motor coordination showed a trend in favor of children from higher SES. The results suggest that public and local authorities should consider providing equal opportunities for children in all social strata and especially those in the lower SES to experience the beneficial effects of sport participation through which they can enhance levels of physical fitness and motor coordination. PMID:22433257

  6. Fitness consequences of maternal and embryonic responses to environmental variation: using reptiles as models for studies of developmental plasticity.

    PubMed

    Warner, Daniel A

    2014-11-01

    Environmental factors strongly influence phenotypic variation within populations. The environment contributes to this variation in two ways: (1) by acting as a determinant of phenotypic variation (i.e., plastic responses) and (2) as an agent of selection that "chooses" among existing phenotypes. Understanding how these two environmental forces contribute to phenotypic variation is a major goal in the field of evolutionary biology and a primary objective of my research program. The objective of this article is to provide a framework to guide studies of environmental sources of phenotypic variation (specifically, developmental plasticity and maternal effects, and their adaptive significance). Two case studies from my research on reptiles are used to illustrate the general approaches I have taken to address these conceptual topics. Some key points for advancing our understanding of environmental influences on phenotypic variation include (1) merging laboratory-based research that identifies specific environmental effects with field studies to validate ecological relevance; (2) using controlled experimental approaches that mimic complex environments found in nature; (3) integrating data across biological fields (e.g., genetics, morphology, physiology, behavior, and ecology) under an evolutionary framework to provide novel insights into the underlying mechanisms that generate phenotypic variation; (4) assessing fitness consequences using measurements of survival and/or reproductive success across ontogeny (from embryos to adults) and under multiple ecologically-meaningful contexts; and (5) quantifying the strength and form of natural selection in multiple populations over multiple periods of time to understand the spatial and temporal consistency of phenotypic selection. Research programs that focus on organisms that are amenable to these approaches will provide the most promise for advancing our understanding of the environmental factors that generate the remarkable

  7. Ontogenic behavioral consistency, individual variation and fitness consequences among lady beetles.

    PubMed

    Rodrigues, Alice S; Botina, Lisbetd; Nascimento, Carolina P; Gontijo, Lessando M; Torres, Jorge B; Guedes, Raul Narciso C

    2016-10-01

    The potential relevance of complete metamorphosis for the individual variation in sets of behavioral traits and their fitness consequences in predatory species led to the present study. A set of nine behavioral traits were assessed for the larvae and adults of a pyrethroid-resistant and a susceptible population of the lady beetle Eriopis connexa. The aim was to assess: 1) the average individual behavioral (pheno)types and their within-population variation, 2) their ontogenic behavioral consistency from larva to adult, and 3) whether the observed correlated sets of behavioral traits can impact fitness. The average behavioral type differed between populations. The pyrethroid-resistant population consistently exhibited lower aggressiveness (as larvae) and exploration, but showed higher activity, as well as larva sociality, and sometimes boldness than the susceptible population. Behavioral trait variation was higher among pyrethroid-resistant individuals, particularly during the larval stage, but there was significant behavior correlation between larvae and adults, regardless of the insect population. Reduced aggressiveness, and to a lesser extent intermediate levels of boldness against heterospecific individuals were associated with higher population growth. Besides shedding light on the ontogenic consistency of behavioral traits and their fitness impact, our results also suggest that reduced aggressiveness is associated with predator population increase, but may compromise its effectiveness as a biocontrol agent. PMID:27523284

  8. Tikhonov adaptively regularized gamma variate fitting to assess plasma clearance of inert renal markers

    PubMed Central

    Puetter, Richard C.; Ling, Lin; Babyn, Paul S.

    2010-01-01

    The Tk-GV model fits Gamma Variates (GV) to data by Tikhonov regularization (Tk) with shrinkage constant, λ, chosen to minimize the relative error in plasma clearance, CL (ml/min). Using 169Yb-DTPA and 99mTc-DTPA (n = 46, 8–9 samples, 5–240 min) bolus-dilution curves, results were obtained for fit methods: (1) Ordinary Least Squares (OLS) one and two exponential term (E1 and E2), (2) OLS-GV and (3) Tk-GV. Four tests examined the fit results for: (1) physicality of ranges of model parameters, (2) effects on parameter values when different data subsets are fit, (3) characterization of residuals, and (4) extrapolative error and agreement with published correction factors. Test 1 showed physical Tk-GV results, where OLS-GV fits sometimes-produced nonphysical CL. Test 2 showed the Tk-GV model produced good results with 4 or more samples drawn between 10 and 240 min. Test 3 showed that E1 and E2 failed goodness-of-fit testing whereas GV fits for t > 20 min were acceptably good. Test 4 showed CLTk-GV clearance values agreed with published CL corrections with the general result that CLE1 > CLE2 > CLTk-GV and finally that CLTk-GV were considerably more robust, precise and accurate than CLE2, and should replace the use of CLE2 for these renal markers. PMID:20865304

  9. Fitness and genetic variation of Viola calaminaria, an endemic metallophyte: implications of population structure and history.

    PubMed

    Bizoux, J-P; Daïnou, K; Raspé, O; Lutts, S; Mahy, G

    2008-11-01

    We investigated variations in genetic diversity and plant fitness in a rare endemic metallophyte of calamine soils, Viola calaminaria, in relation to population size, population connectivity and population history in order to evaluate and discuss potential conservation strategies for the species. Mean population genetic diversity (H(s) = 0.25) of V. calaminaria was similar to endemic non-metallophyte taxa. Twenty-one per cent of the genetic variation was partitioned among populations and a low (9%) but significant differentiation was found among geographical regions. Our results did not support the hypothesis that the acquisition of metal tolerance may result in reduced genetic diversity, and suggested that strict metallophytes do not exhibit higher inter-population differentiation resulting from scattered habitats. There were no relationships between population genetic diversity and population size. Significant correlations were found between plant fitness and (i) population size and (ii) connectivity index. Recently-founded populations exhibited the same level of genetic diversity as ancient populations and also possessed higher plant fitness. There was no indication of strong founder effects in recently-established populations. The results suggest that the creation of habitats through human activities could provide new opportunities for conservation of this species.

  10. Are Observed Variations of Topography of The '660' Influenced By Lateral Variations of An Underlying Interface ?

    NASA Astrophysics Data System (ADS)

    Castillo, J.; Mocquet, A.; Vacher, P.; Sotin, C.

    Most global studies of lateral variations of topography of the '660' have been per- formed so far with long-period data. This presentation assess the seismic signature of this region when studied with broadband data in the frequency range 0.1-1 Hz. When sampled with P-to-s converted phases, this region shows a complex pattern, associat- ing 3 interfaces at the average depths of 600, 650 and 715 km. First results indicate that lateral topography variations of the '650' fit previous observations by long-period data (Gu et al., 1998), except in some subduction zones, especially in East Asia, where vari- ation trends appear to behave in an opposite way. In such regions, better correlations are found with the behaviour of the '715'. We propose that the seismic signature of long-period waves generated at the bottom of the transition zone may be influenced by both interfaces. Because of the lateral variations of their thickness and velocity jump as a function of thermal context, the signature of one interface could prevail against the other. The transformation of garnet into perovskite, and dissociation of ringwood- ite are tested as possible candidates for the '715' and '650', respectively (Vacher et al., 1998), using available thermoelastic data. Synthetic modelling of converted phases on the velocity profiles computed in different thermal contexts can explain our broadband observations. References : Gu et al., EPSL, 157, 57-67, 1998 ; Vacher et al., PEPI, 106, 275-298, 1998.

  11. Influence of activity patterns in fitness during youth.

    PubMed

    Aires, L; Silva, G; Martins, C; Santos, M P; Ribeiro, J C; Mota, J

    2012-04-01

    The aim of this study was to analyze longitudinal associations between cardiorespiratory fitness, physical activity and body mass index in a 4-year longitudinal study. 170 students (97 girls and 73 boys) aged at baseline from 11 to 17 years were followed. Students performed 20-m-SR; physical activity patterns and parents' education were evaluated using a standard questionnaire. Body mass index was categorized according to established cut points. In a multilevel analysis using MLwIN, 2 level structures were defined: first for individuals and second for time observations. In a longitudinal 2 level analysis, cardiorespiratory fitness was -negatively associated with body mass index for girls and boys, respectively (p<0.05; R2=0.63; 0.62), especially with obesity category (p<0.01; R2=0.58; 0.60). In girls, independent associations were observed between CRF and PA categories regarding participation "almost every day" in organized (p<0.05; R2=0.50) and non-organized sports outside school (p<0.05; R2=0.52) and participation in sports competitions (p<0.05; R2=0.51). In boys, associations were found only with participation in sports competitions (p<0.05; R2=0.50). The results highlight the importance of youth participation in organized activities and competitive sports over time to achieve health-related fitness benefits.

  12. Is death-feigning adaptive? Heritable variation in fitness difference of death-feigning behaviour.

    PubMed Central

    Miyatake, Takahisa; Katayama, Kohji; Takeda, Yukari; Nakashima, Akiko; Sugita, Atsushi; Mizumoto, Makoto

    2004-01-01

    The adaptation of death-feigning (thanatosis), a subject that has been overlooked in evolutionary biology, was inferred in a model prey-and-predator system. We studied phenotypic variation among individuals, fitness differences, and the inheritance of death-feigning behaviour in the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Two-way artificial selections for the duration of death-feigning, over 10 generations, showed a clear direct response in the trait and a correlated response in the frequency of death-feigning, thus indicating variation and inheritance of death-feigning behaviour. A comparison of the two selected strains with divergent frequencies of death-feigning showed a significant difference in the fitness for survival when a model predator, a female Adanson jumper spider, Hasarius adansoni Audouin (Araneomophae: Salticidae), was presented to the beetles. The frequency of predation was lower among beetles from strains selected for long-duration than among those for short-duration death-feigning. The results indicate the possibility of the evolution of death-feigning under natural selection. PMID:15539355

  13. Influence of Design Variations on Systems Performance

    NASA Technical Reports Server (NTRS)

    Tumer, Irem Y.; Stone, Robert B.; Huff, Edward M.; Norvig, Peter (Technical Monitor)

    2000-01-01

    High-risk aerospace components have to meet very stringent quality, performance, and safety requirements. Any source of variation is a concern, as it may result in scrap or rework. poor performance, and potentially unsafe flying conditions. The sources of variation during product development, including design, manufacturing, and assembly, and during operation are shown. Sources of static and dynamic variation during development need to be detected accurately in order to prevent failure when the components are placed in operation. The Systems' Health and Safety (SHAS) research at the NASA Ames Research Center addresses the problem of detecting and evaluating the statistical variation in helicopter transmissions. In this work, we focus on the variations caused by design, manufacturing, and assembly of these components, prior to being placed in operation (DMV). In particular, we aim to understand and represent the failure and variation information, and their correlation to performance and safety and feed this information back into the development cycle at an early stage. The feedback of such critical information will assure the development of more reliable components with less rework and scrap. Variations during design and manufacturing are a common source of concern in the development and production of such components. Accounting for these variations, especially those that have the potential to affect performance, is accomplished in a variety ways, including Taguchi methods, FMEA, quality control, statistical process control, and variation risk management. In this work, we start with the assumption that any of these variations can be represented mathematically, and accounted for by using analytical tools incorporating these mathematical representations. In this paper, we concentrate on variations that are introduced during design. Variations introduced during manufacturing are investigated in parallel work.

  14. The influence of horizontal gene transfer on the mean fitness of unicellular populations in static environments.

    PubMed

    Raz, Yoav; Tannenbaum, Emmanuel

    2010-05-01

    Horizontal gene transfer (HGT) is believed to be a major source of genetic variation, particularly for prokaryotes. It is believed that horizontal gene transfer plays a major role in shaping bacterial genomes and is also believed to be responsible for the relatively rapid dissemination and acquisition of new, adaptive traits across bacterial strains. Despite the importance of horizontal gene transfer as a major source of genetic variation, the bulk of research on theoretical evolutionary dynamics and population genetics has focused on point mutations (sometimes coupled with gene duplication events) as the main engine of genomic change. Here, we seek to specifically model HGT processes in bacterial cells, by developing a mathematical model describing the influence that conjugation-mediated HGT has on the mutation-selection balance in an asexually reproducing population of unicellular, prokaryotic organisms. It is assumed that mutation-selection balance is reached in the presence of a fixed background concentration of antibiotic, to which the population must become resistant to survive. We find that HGT has a nontrivial effect on the mean fitness of the population. However, one of the central results that emerge from our analysis is that, at mutation-selection balance, conjugation-mediated HGT has a slightly deleterious effect on the mean fitness of a population. Therefore, we conclude that HGT does not confer a selection advantage in static environments. Rather, its advantage must lie in its ability to promote faster adaptation in dynamic environments, an interpretation that is consistent with the observation that HGT can be promoted by environmental stresses on a population. PMID:20194966

  15. Socio-Cultural Influences in Eating Disorders: Focus on Sports/Fitness Program.

    ERIC Educational Resources Information Center

    Moriarty, Dick; Moriarty, Mary

    This report notes that eating disorders are frequently described as a diet and fitness program gone wild. It outlines and describes five sociocultural influences which have been identified for eating disorders: (1) emphasis on thinness; (2) glorification of youth; (3) changing roles of women; (4) emphasis on fitness and sport programs; and (5) the…

  16. Could Sport Specialization Influence Fitness and Health of Adults with Mental Retardation?

    ERIC Educational Resources Information Center

    Guidetti, Laura; Franciosi, Emanuele; Gallotta, Maria Chiara; Emerenziani, Gian Pietro; Baldari, Carlo

    2010-01-01

    Although several studies showed the positive effects of exercise and physical activity on health and well-being for individuals with ID, there is a lack of information about the influence of sport specialization on fitness and health components. Therefore, the aims of this study were to assess: (a) physical fitness of athletes with intellectual…

  17. Influence of school community and fitness on prevalence of overweight in Australian school children.

    PubMed

    Cochrane, Thomas; Davey, Rachel C; de Castella, F Robert

    2015-12-01

    The study objectives were (1) to determine the variation in prevalence of overweight between school communities, (2) to evaluate the relationship between cardiorespiratory fitness and the probability of being overweight among different school communities, and (3) to test whether this relationship varies between school communities. Using a repeated cross-sectional design, data from 31,424 (15,298 girls, 16,126 boys) Australian school children who had objective assessments of body composition and physical performance were used. Ninety-one schools located across 5 states and territories were included. Independent samples were taken across 12 school years (2000-2011). Analysis used generalised linear mixed models in R with a two-level hierarchical structure-children, nested within school communities. Predictor variables considered were: level 1-gender, age, cardiorespiratory fitness and year of measurement; level 2-school community. A total of 24.6% of the children were overweight and 69% were of low fitness. Variation in the prevalence of overweight between school communities was significant, ranging from 19% to 34%. The probability of being overweight was negatively associated with increasing cardiorespiratory fitness. The relationship was steepest at low fitness and varied markedly between school communities. Children of low fitness had probabilities of being overweight ranging between 26% and 75% depending on school community, whereas those of high fitness had probabilities of <2%. Our findings suggest that most might be gained from a public health perspective by focusing intervention on the least fit children in the worst-performing communities.

  18. A gamma variate model that includes stretched exponential is a better fit for gastric emptying data from mice

    PubMed Central

    Bajzer, Željko; Gibbons, Simon J.; Coleman, Heidi D.; Linden, David R.

    2015-01-01

    Noninvasive breath tests for gastric emptying are important techniques for understanding the changes in gastric motility that occur in disease or in response to drugs. Mice are often used as an animal model; however, the gamma variate model currently used for data analysis does not always fit the data appropriately. The aim of this study was to determine appropriate mathematical models to better fit mouse gastric emptying data including when two peaks are present in the gastric emptying curve. We fitted 175 gastric emptying data sets with two standard models (gamma variate and power exponential), with a gamma variate model that includes stretched exponential and with a proposed two-component model. The appropriateness of the fit was assessed by the Akaike Information Criterion. We found that extension of the gamma variate model to include a stretched exponential improves the fit, which allows for a better estimation of T1/2 and Tlag. When two distinct peaks in gastric emptying are present, a two-component model is required for the most appropriate fit. We conclude that use of a stretched exponential gamma variate model and when appropriate a two-component model will result in a better estimate of physiologically relevant parameters when analyzing mouse gastric emptying data. PMID:26045615

  19. Sex-specific fitness variation in gynodioecious Beta vulgaris ssp. maritima: do empirical observations fit theoretical predictions?

    PubMed

    De Cauwer, I; Arnaud, J-F; Courseaux, A; Dufay, M

    2011-11-01

    In gynodioecious species, in which hermaphroditic and female plants co-occur, the maintenance of sexual polymorphism relies on the genetic determination of sex and on the relative fitness of the different phenotypes. Flower production, components of male fitness (pollen quantity and pollen quality) and female fitness (fruit and seed set) were measured in gynodioecious Beta vulgaris spp. maritima, in which sex is determined by interactions between cytoplasmic male sterility (CMS) genes and nuclear restorers of male fertility. The results suggested that (i) female had a marginal advantage over hermaphrodites in terms of flower production only, (ii) restored CMS hermaphrodites (carrying both CMS genes and nuclear restorers) suffered a slight decrease in fruit production compared to non-CMS hermaphrodites and (iii) restored CMS hermaphrodites were poor pollen producers compared to non-CMS hermaphrodites, probably as a consequence of complex determination of restoration. These observations potentially have important consequences for the conditions of maintenance of sexual polymorphism in B. vulgaris and are discussed in the light of existing theory on evolutionary dynamics of gynodioecy.

  20. Cardiorespiratory fitness attenuates the influence of amyloid on cognition

    PubMed Central

    Schultz, Stephanie A.; Boots, Elizabeth A.; Almeida, Rodrigo P.; Oh, Jennifer M.; Einerson, Jean; Korcarz, Claudia E.; Edwards, Dorothy F.; Koscik, Rebecca L.; Dowling, Maritza N.; Gallagher, Catherine L.; Bendlin, Barbara B.; Christian, Bradley T.; Zetterberg, Henrik; Blennow, Kaj; Carlsson, Cynthia M.; Asthana, Sanjay; Hermann, Bruce P.; Sager, Mark A.; Johnson, Sterling C.; Stein, James H.; Okonkwo, Ozioma C.

    2015-01-01

    Objective To examine cross-sectionally whether higher cardiorespiratory fitness (CRF) might favorably modify amyloid-β (Aβ)-related decrements in cognition in a cohort of late-middle-aged adults at risk for Alzheimer's disease (AD). Methods Sixty-nine enrollees in the Wisconsin Registry for Alzheimer's Prevention participated in this study. They completed a comprehensive neuropsychological exam, underwent 11C Pittsburgh Compound B (PiB)-PET imaging, and performed a graded treadmill exercise test to volitional exhaustion. Peak oxygen consumption (VO2peak) during the exercise test was used as the index of CRF. Forty-five participants also underwent lumbar puncture for collection of cerebrospinal fluid (CSF) samples, from which Aβ42 was immunoassayed. Covariate-adjusted regression analyses were used to test whether the association between Aβ and cognition was modified by CRF. Results There were significant VO2peak*PiB-PET interactions for Immediate Memory (p= .041) and Verbal Learning & Memory (p= .025). There were also significant VO2peak*CSF Aβ42 interactions for Immediate Memory (p<.001) and Verbal Learning & Memory (p <.001). Specifically, in the context of high Aβ burden—i.e., increased PiB-PET binding or reduced CSF Aβ42—individuals with higher CRF exhibited significantly better cognition compared with individuals with lower CRF. Conclusion In a late-middle-aged, at-risk cohort, higher CRF is associated with a diminution of Aβ-related effects on cognition. These findings suggest that exercise might play an important role in the prevention of AD. PMID:26581795

  1. Cardiorespiratory Fitness Attenuates the Influence of Amyloid on Cognition.

    PubMed

    Schultz, Stephanie A; Boots, Elizabeth A; Almeida, Rodrigo P; Oh, Jennifer M; Einerson, Jean; Korcarz, Claudia E; Edwards, Dorothy F; Koscik, Rebecca L; Dowling, Maritza N; Gallagher, Catherine L; Bendlin, Barbara B; Christian, Bradley T; Zetterberg, Henrik; Blennow, Kaj; Carlsson, Cynthia M; Asthana, Sanjay; Hermann, Bruce P; Sager, Mark A; Johnson, Sterling C; Stein, James H; Okonkwo, Ozioma C

    2015-11-01

    The aim of this study was to examine cross-sectionally whether higher cardiorespiratory fitness (CRF) might favorably modify amyloid-β (Aβ)-related decrements in cognition in a cohort of late-middle-aged adults at risk for Alzheimer's disease (AD). Sixty-nine enrollees in the Wisconsin Registry for Alzheimer's Prevention participated in this study. They completed a comprehensive neuropsychological exam, underwent 11C Pittsburgh Compound B (PiB)-PET imaging, and performed a graded treadmill exercise test to volitional exhaustion. Peak oxygen consumption (VO2peak) during the exercise test was used as the index of CRF. Forty-five participants also underwent lumbar puncture for collection of cerebrospinal fluid (CSF) samples, from which Aβ42 was immunoassayed. Covariate-adjusted regression analyses were used to test whether the association between Aβ and cognition was modified by CRF. There were significant VO2peak*PiB-PET interactions for Immediate Memory (p=.041) and Verbal Learning & Memory (p=.025). There were also significant VO2peak*CSF Aβ42 interactions for Immediate Memory (p<.001) and Verbal Learning & Memory (p<.001). Specifically, in the context of high Aβ burden, that is, increased PiB-PET binding or reduced CSF Aβ42, individuals with higher CRF exhibited significantly better cognition compared with individuals with lower CRF. In a late-middle-aged, at-risk cohort, higher CRF is associated with a diminution of Aβ-related effects on cognition. These findings suggest that exercise might play an important role in the prevention of AD.

  2. The influence of acute intense exercise on exogenous spatial attention depends on physical fitness level.

    PubMed

    Llorens, Francesc; Sanabria, Daniel; Huertas, Florentino

    2015-01-01

    We investigated the effect of a previous bout of intense exercise on exogenous spatial attention. In Experiment 1, a group of participants performed an exogenous spatial task at rest (without prior effort), immediately after intense exercise, and after recovering from an intense exercise. The analyses revealed that the typical "facilitation effect" (i.e., faster reaction times on cued than on uncued trials) immediately after exercise was positively correlated with participants' fitness level. In Experiment 2, a high-fit and a low-fit group performed the same task at rest (without prior effort) and immediately after an intense exercise. Results revealed that, after the bout of exercise, only low-fit participants showed reduced attentional effects compared to the rest condition. We argue that the normal functioning of exogenous attention was influenced by intense effort, affecting low-fit participants to a larger extent than to high-fit participants. As a consequence, target processing was prioritized over irrelevant stimuli.

  3. Parent influences on physical activity participation and physical fitness of deaf children.

    PubMed

    Ellis, M Kathleen; Lieberman, Lauren J; Dummer, Gail M

    2014-04-01

    Research has consistently demonstrated that parents' values toward physical activity and fitness have strongly influenced the physical activity habits of hearing children (Welk, G. J., Wood, K., & Morss, G. [2003]. Parental influences on physical activity in children: An exploration of potential mechanisms. Pediatric Exercise Science, 15, 19-33). The primary purpose of this study was to determine whether similar findings are obtained for deaf (1) children. The influence of parents' hearing status and parents' involvement in Deaf sport (2) was assessed in addition to their values toward sports participation and physical fitness for their deaf children. Deaf children's physical activity habits were determined by the number of activities participated per week, and fitness levels by the number of scores within the Healthy Fitness Zone from the Fitnessgram test. Parents demonstrated positive values toward physical fitness regardless of hearing status; this finding was strongest among deaf parents of deaf children. Significant positive relationships were found among parents' values toward physical fitness and sport participation and children's physical activity and fitness levels, as well as between Deaf sport involvement by deaf parents and children's physical activity levels.

  4. Influence of wettability variations on dynamic effects in capillary pressure

    NASA Astrophysics Data System (ADS)

    O'Carroll, Denis M.; Mumford, Kevin G.; Abriola, Linda M.; Gerhard, Jason I.

    2010-08-01

    Traditional continuum-based multiphase simulators incorporate a capillary pressure-saturation relationship that assumes instantaneous attainment of equilibrium following a disturbance. This assumption may not be appropriate for systems where the capillary pressure is a function of the rate of change of saturation, a phenomenon referred to as dynamic capillary pressure. Previous studies have investigated the impact of soil and fluid properties on dynamic effects in capillary pressure; however, the impact of wettability on this phenomenon has not been investigated to date. In this study, two-phase multistep outflow (MSO) experiments conducted in chemically treated sands with different equilibrium contact angles were used to investigate the influence of wettability variations on dynamic effects in capillary pressure during displacement of water by tetrachloroethene (PCE). Data from the MSO experiments were modeled with a multiphase flow simulator that includes dynamic effects and were also analyzed through comparisons with theoretical model predictions for interface movement in a single capillary tube. Results showed that a faster approach to equilibrium, characterized by smaller fitted damping coefficients, occurred in sands with larger equilibrium contact angles. Damping coefficients for sands with an operational contact angle greater than 80° were found to be an order of magnitude smaller than those with an operational contact angle less than 65°. These results suggest that it may be possible to neglect dynamic effects in capillary pressure in systems that approach intermediate-wet conditions but that these effects will be increasingly important in more water-wet systems.

  5. Intraspecific genetic variation and competition interact to influence niche expansion

    PubMed Central

    Agashe, Deepa; Bolnick, Daniel I.

    2010-01-01

    Theory and empirical evidence show that intraspecific competition can drive selection favouring the use of novel resources (i.e. niche expansion). The evolutionary response to such selection depends on genetic variation for resource use. However, while genetic variation might facilitate niche expansion, genetically diverse groups may also experience weaker competition, reducing density-dependent selection on resource use. Therefore, genetic variation for fitness on different resources could directly facilitate, or indirectly retard, niche expansion. To test these alternatives, we factorially manipulated both the degree of genetic variation and population density in flour beetles (Tribolium castaneum) exposed to both novel and familiar food resources. Using stable carbon isotope analysis, we measured temporal change and individual variation in beetle diet across eight generations. Intraspecific competition and genetic variation acted on different components of niche evolution: competition facilitated niche expansion, while genetic variation increased individual variation in niche use. In addition, genetic variation and competition together facilitated niche expansion, but all these impacts were temporally variable. Thus, we show that the interaction between genetic variation and competition can also determine niche evolution at different time scales. PMID:20462902

  6. Influence of physical fitness, age, experience, and weekly training load on match performance in elite Australian football.

    PubMed

    Gastin, Paul B; Fahrner, Brendan; Meyer, Denny; Robinson, Dean; Cook, Jill L

    2013-05-01

    Season long competition schedules in football create unique challenges for coaches in balancing the requirements of recovery, developing and maintaining physical fitness, and adjusting the training load before each match. The aim of this study was to investigate the influence of player characteristics (physical fitness, age, and playing experience) and weekly in-season training load on elite match performance across an Australian football season. Twenty-five players (age: 24.1 ± 3.0 years; height: 188.3 ± 7.3 cm; weight: 90.4 ± 8.3 kg) from one elite team participated in this study. Before the season, player's age, experience, height, and weight along with measures of aerobic (6-minute run) and anaerobic (6 × 40 m repeated sprints) physical fitness were recorded. Individual player training load during the season was measured using global positioning system technology for the main training session of the week. Player match performance was calculated weekly from 33 individual playing statistics. Multilevel modeling was used to investigate the relationship between weekly training load and match performance and to explore the influence of player characteristics on this relationship. Playing experience (p < 0.01) and aerobic fitness (p < 0.05) displayed positive relationships with performance, whereas player age (p < 0.01) showed a negative relationship. Most players coped well with weekly variations in training load; however, the relationship was moderated by the results of the preseason repeated sprint test (p < 0.05). The adverse effect on playing performance in selected players after a more intense training session suggests that recovery from the session may be delayed in players who exhibit a better anaerobic fitness profile.

  7. Cognitive Performance and Heart Rate Variability: The Influence of Fitness Level

    PubMed Central

    Luque-Casado, Antonio; Zabala, Mikel; Morales, Esther; Mateo-March, Manuel; Sanabria, Daniel

    2013-01-01

    In the present study, we investigated the relation between cognitive performance and heart rate variability as a function of fitness level. We measured the effect of three cognitive tasks (the psychomotor vigilance task, a temporal orienting task, and a duration discrimination task) on the heart rate variability of two groups of participants: a high-fit group and a low-fit group. Two major novel findings emerged from this study. First, the lowest values of heart rate variability were found during performance of the duration discrimination task, compared to the other two tasks. Second, the results showed a decrement in heart rate variability as a function of the time on task, although only in the low-fit group. Moreover, the high-fit group showed overall faster reaction times than the low-fit group in the psychomotor vigilance task, while there were not significant differences in performance between the two groups of participants in the other two cognitive tasks. In sum, our results highlighted the influence of cognitive processing on heart rate variability. Importantly, both behavioral and physiological results suggested that the main benefit obtained as a result of fitness level appeared to be associated with processes involving sustained attention. PMID:23437276

  8. Response to environmental change: genetic variation and fitness in Drosophila buzzatii following temperature stress.

    PubMed

    Krebs, R A; Loeschcke, V

    1994-01-01

    Drosophila buzzatii typically may encounter high temperatures in nature, and this species is genetically variable for resistance to stress, both within and among populations. Fitness of survivors to stress, however, was reduced, and observed as a reduction in male fertility and female fecundity. With time following exposure to severe stress, reproductive capacity improved, but lifetime offspring production still was reduced significantly. This effect would greatly reduce a population's recovery from small size, which could occur following exposure to some man-made or environmental extreme. Although the results presented here were obtained for effects of heat stress, such consequences likely apply to a wide range of natural and man-made environmental stresses, including heavy metal toxicity or other pollutants. Low levels of these pollutants may not cause an observable effect on populations, even if some individuals are killed or offspring production is decreased. If genetic variation for resistance is present, higher tolerance may evolve. However, if concentrations are permitted to rise too far, some stress threshold may be reached, as observed for thermal stress, causing mass die-off or sterility and, possibly, local extinction. Understanding the effects of stress is important when preparing programs for the conservation of species. Organisms generally do not become extinct when resources are abundant and the climate benign, but unfortunately, no guarantee can be made that environmental conditions in any locality will remain stable over a long time. Consequently, a high possibility of exposure to an extreme stress in an area would greatly reduce its usefulness as a reserve. Likewise, when choosing organisms for reintroduction, stress resistance of the chosen individuals and high levels of genetic variation within a population would be valuable. The organisms placed there must be able to change. Analysis of stress resistance (at non-lethal levels) among either

  9. Phenotypic Variation in Fitness Traits of a Managed Solitary Bee, Osmia ribifloris (Hymenoptera: Megachilidae).

    PubMed

    Sampson, B J; Rinehart, T A; Kirker, G T; Stringer, S J; Werle, C T

    2015-12-01

    We investigated fitness in natural populations of a managed solitary bee Osmia ribifloris Cockerell (Hymenoptera: Megachilidae) from sites separated from 400 to 2,700 km. Parental wild bees originated in central Texas (TX), central-northern Utah (UT), and central California (CA). They were then intercrossed and raised inside a mesh enclosure in southern Mississippi (MS). Females from all possible mated pairs of O. ribifloris produced F1 broods with 30-40% female cocoons and outcrossed progeny were 30% heavier. Mitochondrial (COI) genomes of the four populations revealed three distinct clades, a TX-CA clade, a UT clade, and an MS clade, the latter (MS) representing captive progeny of CA and UT bees. Although classified as separate subspecies, TX and CA populations from 30° N to 38° N latitude shared 98% similarity in COI genomes and the greatest brood biomass per nest straw (600- to 700-mg brood). Thus, TX and CA bees show greater adaptation for southern U.S. sites. In contrast, UT-sourced bees were more distantly related to TX and CA bees and also produced ∼50% fewer brood. These results, taken together, confirm that adult O. ribifloris from all trap-nest sites are genetically compatible, but some phenotypic variation exists that could affect this species performance as a commercial blueberry pollinator. Males, their sperm, or perhaps a substance in their sperm helped stabilize our captive bee population by promoting legitimate nesting over nest usurpation. Otherwise, without insemination, 50% fewer females nested (they nested 14 d late) and 20% usurped nests, killing 33-67% of brood in affected nests.

  10. Phenotypic Variation in Fitness Traits of a Managed Solitary Bee, Osmia ribifloris (Hymenoptera: Megachilidae).

    PubMed

    Sampson, B J; Rinehart, T A; Kirker, G T; Stringer, S J; Werle, C T

    2015-12-01

    We investigated fitness in natural populations of a managed solitary bee Osmia ribifloris Cockerell (Hymenoptera: Megachilidae) from sites separated from 400 to 2,700 km. Parental wild bees originated in central Texas (TX), central-northern Utah (UT), and central California (CA). They were then intercrossed and raised inside a mesh enclosure in southern Mississippi (MS). Females from all possible mated pairs of O. ribifloris produced F1 broods with 30-40% female cocoons and outcrossed progeny were 30% heavier. Mitochondrial (COI) genomes of the four populations revealed three distinct clades, a TX-CA clade, a UT clade, and an MS clade, the latter (MS) representing captive progeny of CA and UT bees. Although classified as separate subspecies, TX and CA populations from 30° N to 38° N latitude shared 98% similarity in COI genomes and the greatest brood biomass per nest straw (600- to 700-mg brood). Thus, TX and CA bees show greater adaptation for southern U.S. sites. In contrast, UT-sourced bees were more distantly related to TX and CA bees and also produced ∼50% fewer brood. These results, taken together, confirm that adult O. ribifloris from all trap-nest sites are genetically compatible, but some phenotypic variation exists that could affect this species performance as a commercial blueberry pollinator. Males, their sperm, or perhaps a substance in their sperm helped stabilize our captive bee population by promoting legitimate nesting over nest usurpation. Otherwise, without insemination, 50% fewer females nested (they nested 14 d late) and 20% usurped nests, killing 33-67% of brood in affected nests. PMID:26470379

  11. Influences of genetic variation on fetal hemoglobin.

    PubMed

    He, Yunyan; Lin, Weixiong; Luo, Jianming

    2011-11-01

    Fetal hemoglobin (HbF) plays a dominant role in ameliorating morbidity and mortality of hemoglobinopathies. The authors performed a replicated study following the genome-wide association study (GWAS) guidelines to identify the genetic mechanics that influence HbF. The authors recruited and phenotyped 312 unrelated β-thalassemia subjects. Single-nucleotide polymorphism (SNP) analysis was performed by using polymerase chain reaction (PCR)/restriction enzymes. Four independent regions of interest were identified: HBS1L-MYB intergenic region, BCL11A locus, β-globin gene cluster, and the CSNK2A1 gene. There were 10 SNPs associated with HbF levels. In addition, haplotypes of HBS1L-MYB and BCL11A were identified and showed association with HbF production. Three independent regions, including HBS1L-MYB intergenic region, BCL11A locus, and β-globin gene cluster, were associated with HbF levels. This study can significantly improve the GWAS findings in Chinese cohorts and is useful for further research in the field of common predictors of the erythropoiesis.

  12. Individual Variation in Life History Characteristics Can Influence Extinction Risk

    SciTech Connect

    Jager, H I

    2001-01-01

    The white sturgeon (Acipenser transmontanus) shows great individual variation in the age at maturation. This study examines the consequences of model assumptions about individual variation in the age at maturation on predicted population viability. I considered: (1) the effects of variation in age at maturation alone; (2) the effects of heritability; and (3) the influence of a stable and an altered selective regime. Two selective regimes represented conditions before and after the impoundment of a river, blocking access of anadromous white sturgeon populations to the ocean. In contrast to previous simulation studies, I found that increased individual variation in the age at maturity did not necessarily lead to a higher likelihood of persistence. Individual variation increased the simulated likelihood of persistence when the variation was heritable and the selective regime had changed such that the mean age at maturity was no longer optimal.

  13. A HIERARCHY OF COMPUTATIONALLY DERIVED SURGICAL AND PATIENT INFLUENCES ON METAL ON METAL PRESS-FIT ACETABULAR CUP FAILURE

    PubMed Central

    Clarke, S G; Phillips, A T M; Bull, A M J; Cobb, J P

    2014-01-01

    The impact of anatomical variation and surgical error on excessive wear and loosening of the acetabular component of large diameter metal on metal hip arthroplasties was measured using a multi-factorial analysis through 112 different simulations. Each surgical scenario was subject to eight different daily loading activities using finite element analysis. Excessive wear appears to be predominantly dependent on cup orientation, with inclination error having a higher influence than version error, according to the study findings. Acetabular cup loosening, as inferred from initial implant stability, appears to depend predominantly on factors concerning the area of cup-bone contact, specifically the level of cup seating achieved and the individual patient’s anatomy. The extent of press fit obtained at time of surgery did not appear to influence either mechanism of failure in this study. PMID:22513086

  14. Fitting the Rasch Model to Account for Variation in Item Discrimination

    ERIC Educational Resources Information Center

    Weitzman, R. A.

    2009-01-01

    Building on the Kelley and Gulliksen versions of classical test theory, this article shows that a logistic model having only a single item parameter can account for varying item discrimination, as well as difficulty, by using item-test correlations to adjust incorrect-correct (0-1) item responses prior to an initial model fit. The fit occurs…

  15. Does Plant Origin Influence the Fitness Impact of Flower Damage? A Meta-Analysis.

    PubMed

    González-Browne, Catalina; Murúa, Maureen M; Navarro, Luis; Medel, Rodrigo

    2016-01-01

    Herbivory has been long considered an important component of plant-animal interactions that influences the success of invasive species in novel habitats. One of the most important hypotheses linking herbivory and invasion processes is the enemy-release hypothesis, in which exotic plants are hypothesized to suffer less herbivory and fitness-costs in their novel ranges as they leave behind their enemies in the original range. Most evidence, however, comes from studies on leaf herbivory, and the importance of flower herbivory for the invasion process remains largely unknown. Here we present the results of a meta-analysis of the impact of flower herbivory on plant reproductive success, using as moderators the type of damage caused by floral herbivores and the residence status of the plant species. We found 51 papers that fulfilled our criteria. We also included 60 records from unpublished data of the laboratory, gathering a total of 143 case studies. The effects of florivory and nectar robbing were both negative on plant fitness. The methodology employed in studies of flower herbivory influenced substantially the outcome of flower damage. Experiments using natural herbivory imposed a higher fitness cost than simulated herbivory, such as clipping and petal removal, indicating that studies using artificial herbivory as surrogates of natural herbivory underestimate the real fitness impact of flower herbivory. Although the fitness cost of floral herbivory was high both in native and exotic plant species, floral herbivores had a three-fold stronger fitness impact on exotic than native plants, contravening a critical element of the enemy-release hypothesis. Our results suggest a critical but largely unrecognized role of floral herbivores in preventing the spread of introduced species into newly colonized areas.

  16. Does Plant Origin Influence the Fitness Impact of Flower Damage? A Meta-Analysis.

    PubMed

    González-Browne, Catalina; Murúa, Maureen M; Navarro, Luis; Medel, Rodrigo

    2016-01-01

    Herbivory has been long considered an important component of plant-animal interactions that influences the success of invasive species in novel habitats. One of the most important hypotheses linking herbivory and invasion processes is the enemy-release hypothesis, in which exotic plants are hypothesized to suffer less herbivory and fitness-costs in their novel ranges as they leave behind their enemies in the original range. Most evidence, however, comes from studies on leaf herbivory, and the importance of flower herbivory for the invasion process remains largely unknown. Here we present the results of a meta-analysis of the impact of flower herbivory on plant reproductive success, using as moderators the type of damage caused by floral herbivores and the residence status of the plant species. We found 51 papers that fulfilled our criteria. We also included 60 records from unpublished data of the laboratory, gathering a total of 143 case studies. The effects of florivory and nectar robbing were both negative on plant fitness. The methodology employed in studies of flower herbivory influenced substantially the outcome of flower damage. Experiments using natural herbivory imposed a higher fitness cost than simulated herbivory, such as clipping and petal removal, indicating that studies using artificial herbivory as surrogates of natural herbivory underestimate the real fitness impact of flower herbivory. Although the fitness cost of floral herbivory was high both in native and exotic plant species, floral herbivores had a three-fold stronger fitness impact on exotic than native plants, contravening a critical element of the enemy-release hypothesis. Our results suggest a critical but largely unrecognized role of floral herbivores in preventing the spread of introduced species into newly colonized areas. PMID:26785039

  17. Does Plant Origin Influence the Fitness Impact of Flower Damage? A Meta-Analysis

    PubMed Central

    González-Browne, Catalina; Murúa, Maureen M.; Navarro, Luis; Medel, Rodrigo

    2016-01-01

    Herbivory has been long considered an important component of plant-animal interactions that influences the success of invasive species in novel habitats. One of the most important hypotheses linking herbivory and invasion processes is the enemy-release hypothesis, in which exotic plants are hypothesized to suffer less herbivory and fitness-costs in their novel ranges as they leave behind their enemies in the original range. Most evidence, however, comes from studies on leaf herbivory, and the importance of flower herbivory for the invasion process remains largely unknown. Here we present the results of a meta-analysis of the impact of flower herbivory on plant reproductive success, using as moderators the type of damage caused by floral herbivores and the residence status of the plant species. We found 51 papers that fulfilled our criteria. We also included 60 records from unpublished data of the laboratory, gathering a total of 143 case studies. The effects of florivory and nectar robbing were both negative on plant fitness. The methodology employed in studies of flower herbivory influenced substantially the outcome of flower damage. Experiments using natural herbivory imposed a higher fitness cost than simulated herbivory, such as clipping and petal removal, indicating that studies using artificial herbivory as surrogates of natural herbivory underestimate the real fitness impact of flower herbivory. Although the fitness cost of floral herbivory was high both in native and exotic plant species, floral herbivores had a three-fold stronger fitness impact on exotic than native plants, contravening a critical element of the enemy-release hypothesis. Our results suggest a critical but largely unrecognized role of floral herbivores in preventing the spread of introduced species into newly colonized areas. PMID:26785039

  18. The fitness of dispersing spotted hyaena sons is influenced by maternal social status.

    PubMed

    Höner, Oliver P; Wachter, Bettina; Hofer, Heribert; Wilhelm, Kerstin; Thierer, Dagmar; Trillmich, Fritz; Burke, Terry; East, Marion L

    2010-01-01

    Life history theory predicts that mothers should provide their offspring with a privileged upbringing if this enhances their offspring's and their own fitness. In many mammals, high-ranking mothers provide their offspring with a privileged upbringing. Whether dispersing sons gain fitness benefits during adulthood from such privileges (a 'silver spoon' effect) has rarely been examined. In this paper, we show that in the complex, female-dominated society of spotted hyaenas, high-born sons grew at higher rates, were more likely to disperse to clans offering the best fitness prospects, started reproducing earlier and had a higher reproductive value than did lower-born sons. This illustrates the evolutionary importance of maternal effects even in societies in which male size or fighting ability does not influence fitness. By demonstrating for the first time in a non-human mammal that maternal status influences immigration patterns, the study also advances our understanding of two key ecological and evolutionary processes, dispersal and habitat selection. PMID:20975715

  19. The Influence of Body Mass Index on Long-Term Fitness from Physical Education in Adolescent Girls

    ERIC Educational Resources Information Center

    Camhi, Sarah M.; Phillips, Jennie; Young, Deborah R.

    2011-01-01

    Background: Physical education (PE) can improve physical fitness; however, little research has evaluated PE's long-term influence. The purpose is to determine PE's longitudinal effects on fitness in a group of adolescent girls and to determine whether body mass index (BMI) status influenced any potential effects. Methods: Participants were…

  20. The influence of age, playing position, anthropometry and fitness on career attainment outcomes in rugby league.

    PubMed

    Till, Kevin; Cobley, Steve; Morley, David; O'hara, John; Chapman, Chris; Cooke, Carlton

    2016-01-01

    This study evaluated the influence of annual-age category, relative age, playing position, anthropometry and fitness on the career attainment outcomes of junior rugby league players originally selected for a talent identification and development (TID) programme. Junior rugby league players (N = 580) were grouped retrospectively according to their career attainment level (i.e., amateur, academy and professional). Anthropometric (height, sitting height, body mass, sum of four skinfolds), maturational (age at peak height velocity; PHV) and fitness (power, speed, change of direction speed, estimated[Formula: see text]) characteristics were assessed at the Under 13s, 14s and 15s annual-age categories. Relative age (Q2 = 8.5% vs. Q4 = 25.5%) and playing position (Pivots = 19.5% vs. Props = 5.8%) influenced the percentage of players attaining professional status. Anthropometry and fitness had a significant effect on career attainment at the Under 14 (P = 0.002, η(2) = 0.16) and 15 (P = 0.01, η(2) = 0.12) annual-age categories. Findings at the Under 14s showed future professional players were significantly later maturing compared to academy and amateur players. Findings suggest that relative age, playing position, anthropometry and fitness can influence the career attainment of junior rugby league players. TID programmes within rugby league, and other related team sports, should be aware and acknowledge the factors influencing long-term career attainment, and not delimit development opportunities during early adolescence.

  1. The influence of age, playing position, anthropometry and fitness on career attainment outcomes in rugby league.

    PubMed

    Till, Kevin; Cobley, Steve; Morley, David; O'hara, John; Chapman, Chris; Cooke, Carlton

    2016-01-01

    This study evaluated the influence of annual-age category, relative age, playing position, anthropometry and fitness on the career attainment outcomes of junior rugby league players originally selected for a talent identification and development (TID) programme. Junior rugby league players (N = 580) were grouped retrospectively according to their career attainment level (i.e., amateur, academy and professional). Anthropometric (height, sitting height, body mass, sum of four skinfolds), maturational (age at peak height velocity; PHV) and fitness (power, speed, change of direction speed, estimated[Formula: see text]) characteristics were assessed at the Under 13s, 14s and 15s annual-age categories. Relative age (Q2 = 8.5% vs. Q4 = 25.5%) and playing position (Pivots = 19.5% vs. Props = 5.8%) influenced the percentage of players attaining professional status. Anthropometry and fitness had a significant effect on career attainment at the Under 14 (P = 0.002, η(2) = 0.16) and 15 (P = 0.01, η(2) = 0.12) annual-age categories. Findings at the Under 14s showed future professional players were significantly later maturing compared to academy and amateur players. Findings suggest that relative age, playing position, anthropometry and fitness can influence the career attainment of junior rugby league players. TID programmes within rugby league, and other related team sports, should be aware and acknowledge the factors influencing long-term career attainment, and not delimit development opportunities during early adolescence. PMID:26512761

  2. Genetic variation in host plants influences the mate preferences of a plant-feeding insect.

    PubMed

    Rebar, Darren; Rodríguez, Rafael L

    2014-10-01

    Many species spend their lives in close association with other organisms, and the environments provided by those organisms can play an important role as causes of variation in phenotypes. When this is the case, the genotypes of the individuals constituting the environment may influence the phenotypes of individuals living in that environment. When these effects are between heterospecifics, interspecific indirect genetic effects (IIGEs) occur. Several studies have detected IIGEs, but whether IIGEs contribute to variation in sexually selected traits remains virtually unexplored. We assessed how mate preferences in a plant-feeding insect are influenced by the genotype of their host plant. We established clone lines of a sample of host plant genotypes constituting the background biotic environment for a random sample of insects that we reared on them. We found that the insects' mate preferences varied according to the clone line on which they developed. These results demonstrate that genetic variation in host plants has cross-trophic consequences on a trait that has strong effects on fitness and interpopulation dynamics such as diversification in communication systems. We discuss how IIGEs on mate preferences may influence the way in which selection acts, including the maintenance of variation and the promotion of evolutionary divergence. PMID:25226184

  3. Genetic variation in host plants influences the mate preferences of a plant-feeding insect.

    PubMed

    Rebar, Darren; Rodríguez, Rafael L

    2014-10-01

    Many species spend their lives in close association with other organisms, and the environments provided by those organisms can play an important role as causes of variation in phenotypes. When this is the case, the genotypes of the individuals constituting the environment may influence the phenotypes of individuals living in that environment. When these effects are between heterospecifics, interspecific indirect genetic effects (IIGEs) occur. Several studies have detected IIGEs, but whether IIGEs contribute to variation in sexually selected traits remains virtually unexplored. We assessed how mate preferences in a plant-feeding insect are influenced by the genotype of their host plant. We established clone lines of a sample of host plant genotypes constituting the background biotic environment for a random sample of insects that we reared on them. We found that the insects' mate preferences varied according to the clone line on which they developed. These results demonstrate that genetic variation in host plants has cross-trophic consequences on a trait that has strong effects on fitness and interpopulation dynamics such as diversification in communication systems. We discuss how IIGEs on mate preferences may influence the way in which selection acts, including the maintenance of variation and the promotion of evolutionary divergence.

  4. Emergence timing and fitness consequences of variation in seed oil composition in Arabidopsis thaliana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early seedling emergence can increase plant fitness under competition. Seed oil composition (the types and relative amounts of fatty acids in the oils) may play an important role in determining emergence timing in oilseeds. Saturated fatty acids provide more energy per carbon atom than unsaturated...

  5. Does Male Care, Provided to Immature Individuals, Influence Immature Fitness in Rhesus Macaques?

    PubMed

    Langos, Doreen; Kulik, Lars; Ruiz-Lambides, Angelina; Widdig, Anja

    2015-01-01

    Among many mammals, maternal care strongly impacts infant survival; however, less is known about whether adult males also affect infant fitness. Paternal care is expected when providing care enhances offspring survival and reproduction, which likewise increases fathers' fitness. Males might also care for unrelated immature individuals to increase their mating probability with the immature individuals' mothers. Studies in multimale primate groups showed that sires enhance food access for offspring and provide protection in conflicts. Furthermore, fathers' presence during infancy has been suggested to accelerate offspring sexual maturation. However, no study has yet directly linked the degree of father-offspring bonds to offspring fitness in primates. We previously reported father-offspring affiliation in rhesus macaques, pronounced during early infancy and independent of mothers' presence. The present study aims at investigating whether affiliation with fathers or other males affects proxies of immature fitness (body mass gain, body fat and testis size). First, we combined behavioral, genetic and morphometric data from 55 subjects of one group. Second, using demographic and genetic data, we investigated for 92 individuals of the population whether mother- and father-offspring co-residence during immaturity influenced offspring lifetime reproductive success (LRS). Our results show that focal rank and higher amounts of affiliation with high-ranking males during infancy tend to positively impact body mass gain of female, but not male focal animals. In contrast, body mass gain of male focal individuals, but not females', appeared to be higher when affiliation of male immature individuals was evenly distributed across their adult male partners. Moreover, we found mothers', but not fathers', presence during immaturity to predict offspring LRS. Our results suggest that male-immature affiliation, but not father-offspring co-residence, potentially impacts proxies of immature

  6. Does Male Care, Provided to Immature Individuals, Influence Immature Fitness in Rhesus Macaques?

    PubMed Central

    Langos, Doreen; Kulik, Lars; Ruiz-Lambides, Angelina; Widdig, Anja

    2015-01-01

    Among many mammals, maternal care strongly impacts infant survival; however, less is known about whether adult males also affect infant fitness. Paternal care is expected when providing care enhances offspring survival and reproduction, which likewise increases fathers’ fitness. Males might also care for unrelated immature individuals to increase their mating probability with the immature individuals’ mothers. Studies in multimale primate groups showed that sires enhance food access for offspring and provide protection in conflicts. Furthermore, fathers’ presence during infancy has been suggested to accelerate offspring sexual maturation. However, no study has yet directly linked the degree of father-offspring bonds to offspring fitness in primates. We previously reported father-offspring affiliation in rhesus macaques, pronounced during early infancy and independent of mothers’ presence. The present study aims at investigating whether affiliation with fathers or other males affects proxies of immature fitness (body mass gain, body fat and testis size). First, we combined behavioral, genetic and morphometric data from 55 subjects of one group. Second, using demographic and genetic data, we investigated for 92 individuals of the population whether mother- and father-offspring co-residence during immaturity influenced offspring lifetime reproductive success (LRS). Our results show that focal rank and higher amounts of affiliation with high-ranking males during infancy tend to positively impact body mass gain of female, but not male focal animals. In contrast, body mass gain of male focal individuals, but not females’, appeared to be higher when affiliation of male immature individuals was evenly distributed across their adult male partners. Moreover, we found mothers’, but not fathers’, presence during immaturity to predict offspring LRS. Our results suggest that male-immature affiliation, but not father-offspring co-residence, potentially impacts

  7. Does Male Care, Provided to Immature Individuals, Influence Immature Fitness in Rhesus Macaques?

    PubMed

    Langos, Doreen; Kulik, Lars; Ruiz-Lambides, Angelina; Widdig, Anja

    2015-01-01

    Among many mammals, maternal care strongly impacts infant survival; however, less is known about whether adult males also affect infant fitness. Paternal care is expected when providing care enhances offspring survival and reproduction, which likewise increases fathers' fitness. Males might also care for unrelated immature individuals to increase their mating probability with the immature individuals' mothers. Studies in multimale primate groups showed that sires enhance food access for offspring and provide protection in conflicts. Furthermore, fathers' presence during infancy has been suggested to accelerate offspring sexual maturation. However, no study has yet directly linked the degree of father-offspring bonds to offspring fitness in primates. We previously reported father-offspring affiliation in rhesus macaques, pronounced during early infancy and independent of mothers' presence. The present study aims at investigating whether affiliation with fathers or other males affects proxies of immature fitness (body mass gain, body fat and testis size). First, we combined behavioral, genetic and morphometric data from 55 subjects of one group. Second, using demographic and genetic data, we investigated for 92 individuals of the population whether mother- and father-offspring co-residence during immaturity influenced offspring lifetime reproductive success (LRS). Our results show that focal rank and higher amounts of affiliation with high-ranking males during infancy tend to positively impact body mass gain of female, but not male focal animals. In contrast, body mass gain of male focal individuals, but not females', appeared to be higher when affiliation of male immature individuals was evenly distributed across their adult male partners. Moreover, we found mothers', but not fathers', presence during immaturity to predict offspring LRS. Our results suggest that male-immature affiliation, but not father-offspring co-residence, potentially impacts proxies of immature

  8. Could sport specialization influence fitness and health of adults with mental retardation?

    PubMed

    Guidetti, Laura; Franciosi, Emanuele; Gallotta, Maria Chiara; Emerenziani, Gian Pietro; Baldari, Carlo

    2010-01-01

    Although several studies showed the positive effects of exercise and physical activity on health and well-being for individuals with ID, there is a lack of information about the influence of sport specialization on fitness and health components. Therefore, the aims of this study were to assess: (a) physical fitness of athletes with intellectual disability (ID) compared with individuals included in recreational and leisure activity programs (non-athletic people); (b) contribution of sport specialization on athletes' fitness; and c) correlation of each fitness variable with subjects' ID levels. Twenty-two track and field, 19 basketball, and 23 non-athletic adults were recruited. Before and after a 9-month period, all participants performed fitness tests assessing body composition, flexibility (SR), arm muscular strength (HG), lower and upper-body muscular strength and endurance (SUP and PUP), explosive leg power (SLJ), cardiovascular endurance (ST), balance ability (FT), motor coordination (TUGT). The results showed that participants' weight, BMI and FT were significantly affected by time; SLJ by activity; ST, HG, PUP, SUP, and TUGT by both time and activity. Only track and field athletes increased significantly ST. All athletes improved significantly HG, PUP and SUP, instead non-athletic people decreased significantly SUP (p<0.01). TUGT improved significantly in track and field athletes (p<0.05), and decreased significantly in non-athletic people. ID level was positively correlated to TUGT. Findings of this study showed that physical activity improved fitness in adult athletes with ID, decreasing health risks. Athletes with lower ID obtained higher performance scores in motor coordination test.

  9. Identification of quantitative genetic components of fitness variation in farmed, hybrid and native salmon in the wild.

    PubMed

    Besnier, F; Glover, K A; Lien, S; Kent, M; Hansen, M M; Shen, X; Skaala, Ø

    2015-07-01

    Feral animals represent an important problem in many ecosystems due to interbreeding with wild conspecifics. Hybrid offspring from wild and domestic parents are often less adapted to local environment and ultimately, can reduce the fitness of the native population. This problem is an important concern in Norway, where each year, hundreds of thousands of farm Atlantic salmon escape from fish farms. Feral fish outnumber wild populations, leading to a possible loss of local adaptive genetic variation and erosion of genetic structure in wild populations. Studying the genetic factors underlying relative performance between wild and domesticated conspecific can help to better understand how domestication modifies the genetic background of populations, and how it may alter their ability to adapt to the natural environment. Here, based upon a large-scale release of wild, farm and wild x farm salmon crosses into a natural river system, a genome-wide quantitative trait locus (QTL) scan was performed on the offspring of 50 full-sib families, for traits related to fitness (length, weight, condition factor and survival). Six QTLs were detected as significant contributors to the phenotypic variation of the first three traits, explaining collectively between 9.8 and 14.8% of the phenotypic variation. The seventh QTL had a significant contribution to the variation in survival, and is regarded as a key factor to understand the fitness variability observed among salmon in the river. Interestingly, strong allelic correlation within one of the QTL regions in farmed salmon might reflect a recent selective sweep due to artificial selection.

  10. Emergence timing and fitness consequences of variation in seed oil composition in Arabidopsis thaliana

    PubMed Central

    Pelc, Sandra E; Linder, C Randal

    2015-01-01

    Early seedling emergence can increase plant fitness under competition. Seed oil composition (the types and relative amounts of fatty acids in the oils) may play an important role in determining emergence timing and early growth rate in oilseeds. Saturated fatty acids provide more energy per carbon atom than unsaturated fatty acids but have substantially higher melting points (when chain length is held constant). This characteristic forms the basis of an adaptive hypothesis that lower melting point seeds (lower proportion of saturated fatty acids) should be favored under colder germination temperatures due to earlier germination and faster growth before photosynthesis, while at warmer germination temperatures, seeds with a higher amount of energy (higher proportion of saturated fatty acids) should be favored. To assess the effects of seed oil melting point on timing of seedling emergence and fitness, high- and low-melting point lines from a recombinant inbred cross of Arabidopsis thaliana were competed in a fully factorial experiment at warm and cold temperatures with two different density treatments. Emergence timing between these lines was not significantly different at either temperature, which aligned with warm temperature predictions, but not cold temperature predictions. Under all conditions, plants competing against high-melting point lines had lower fitness relative to those against low-melting point lines, which matched expectations for undifferentiated emergence times. PMID:25628873

  11. Emergence timing and fitness consequences of variation in seed oil composition in Arabidopsis thaliana.

    PubMed

    Pelc, Sandra E; Linder, C Randal

    2015-01-01

    Early seedling emergence can increase plant fitness under competition. Seed oil composition (the types and relative amounts of fatty acids in the oils) may play an important role in determining emergence timing and early growth rate in oilseeds. Saturated fatty acids provide more energy per carbon atom than unsaturated fatty acids but have substantially higher melting points (when chain length is held constant). This characteristic forms the basis of an adaptive hypothesis that lower melting point seeds (lower proportion of saturated fatty acids) should be favored under colder germination temperatures due to earlier germination and faster growth before photosynthesis, while at warmer germination temperatures, seeds with a higher amount of energy (higher proportion of saturated fatty acids) should be favored. To assess the effects of seed oil melting point on timing of seedling emergence and fitness, high- and low-melting point lines from a recombinant inbred cross of Arabidopsis thaliana were competed in a fully factorial experiment at warm and cold temperatures with two different density treatments. Emergence timing between these lines was not significantly different at either temperature, which aligned with warm temperature predictions, but not cold temperature predictions. Under all conditions, plants competing against high-melting point lines had lower fitness relative to those against low-melting point lines, which matched expectations for undifferentiated emergence times. PMID:25628873

  12. Climatic and Altitudinal Influences on Variation in Macaca Limb Morphology

    PubMed Central

    Weinstein, Karen J.

    2011-01-01

    This study compares limb lengths and joint diameters in the skeletons of six macaque species (Macaca assamensis, M. fascicularis, M. fuscata, M. mulatta, M. nemestrina, and M. thibetana) from a broad range of habitats and climates in order to test whether ambient temperatures, latitude, and altitude influence interspecific variation in limb morphology in this widely dispersed genus. Analysis of variance, principal component analysis, and partial correlation analysis reveal that species from temperate latitudes and high elevations tend to have short limbs and large joint diameters for their sizes while species from tropical latitudes and low elevations tend to have long limbs and small joint diameters. Interspecific variations in intra- and interlimb length proportions also reflect phylogeny and subtle differences in locomotion. The results of this study suggest that climatic conditions are important factors among many ecological variables that influence limb morphology in this geographically widespread genus. PMID:22567298

  13. Influence of an injury reduction program on injury and fitness outcomes among soldiers

    PubMed Central

    Knapik, J; Bullock, S; Canada, S; Toney, E; Wells, J; Hoedebecke, E; Jones, B

    2004-01-01

    Objective: This study evaluated the influence of a multiple injury control intervention on injury and physical fitness outcomes among soldiers attending United States Army Ordnance School Advanced Individual Training. Methods: The study design was quasiexperimental involving a historical control group (n = 2559) that was compared to a multiple intervention group (n = 1283). Interventions in the multiple intervention group included modified physical training, injury education, and a unit based injury surveillance system (UBISS). The management responsible for training independently formed an Injury Control Advisory Committee that examined surveillance reports from the UBISS and recommended changes to training. On arrival at school, individual soldiers completed a demographics and lifestyle questionnaire and took an army physical fitness test (APFT: push-ups, sit-ups, and two mile run). Injuries among soldiers were tracked by a clinic based injury surveillance system that was separate from the UBISS. Soldiers completed a final APFT eight weeks after arrival at school. Results: Cox regression (survival analysis) was used to examine differences in time to the first injury while controlling for group differences in demographics, lifestyle characteristics, and physical fitness. The adjusted relative risk of a time loss injury was 1.5 (95% confidence interval 1.2 to 1.8) times higher in the historical control men and 1.8 (95% confidence interval 1.1 to 2.8) times higher in the historical control women compared with the multiple intervention men and women, respectively. After correcting for the lower initial fitness of the multiple intervention group, there were no significant differences between the multiple intervention and historical control groups in terms of improvements in push-ups, sit-ups, or two mile run performance. Conclusions: This multiple intervention program contributed to a reduction in injuries while improvements in physical fitness were similar to a

  14. A Variation of the F-Test for Determining Statistical Relevance ofParticular Parameters in EXAFS Fits

    SciTech Connect

    Downward, L.; Booth, C.H.; Lukens, W.W.; Bridges, F.

    2006-07-25

    A general problem when fitting EXAFS data is determining whether particular parameters are statistically significant. The F-test is an excellent way of determining relevancy in EXAFS because it only relies on the ratio of the fit residual of two possible models, and therefore the data errors approximately cancel. Although this test is widely used in crystallography (there, it is often called a 'Hamilton test') and has been properly applied to EXAFS data in the past, it is very rarely applied in EXAFS analysis. We have implemented a variation of the F-test adapted for EXAFS data analysis in the RSXAP analysis package, and demonstrate its applicability with a few examples, including determining whether a particular scattering shell is warranted, and differentiating between two possible species or two possible structures in a given shell.

  15. Fitness of Outbreak and Environmental Strains of Escherichia coli O157:H7 in Aerosolizable Soil and Association of Clonal Variation in Stress Gene Regulation

    PubMed Central

    Ravva, Subbarao V.; Cooley, Michael B.; Sarreal, Chester Z.; Mandrell, Robert E.

    2014-01-01

    Airborne dust from feedlots is a potential mechanism of contamination of nearby vegetable crops with Escherichia coli O157:H7 (EcO157). We compared the fitness of clinical and environmental strains of EcO157 in <45 µm soil from a spinach farm. Differences in survival were observed among the 35 strains with D-values (days for 90% decreases) ranging from 1–12 days. Strains that survived longer, generally, were from environmental sources and lacked expression of curli, a protein associated with attachment and virulence. Furthermore, the proportion of curli-positive (C+) variants of EcO157 strains decreased with repeated soil exposure and the strains that were curli-negative (C−) remained C− post-soil exposure. Soil exposure altered expression of stress-response genes linked to fitness of EcO157, but significant clonal variation in expression was measured. Mutations were detected in the stress-related sigma factor, rpoS, with a greater percentage occurring in parental strains of clinical origin prior to soil exposure. We speculate that these mutations in rpoS may confer a differential expression of genes, associated with mechanisms of survival and/or virulence, and thus may influence the fitness of EcO157. PMID:25438010

  16. Cognitive ability influences reproductive life history variation in the wild.

    PubMed

    Cole, Ella F; Morand-Ferron, Julie; Hinks, Amy E; Quinn, John L

    2012-10-01

    Cognition has been studied intensively for several decades, but the evolutionary processes that shape individual variation in cognitive traits remain elusive [1-3]. For instance, the strength of selection on a cognitive trait has never been estimated in a natural population, and the possibility that positive links with life history variation [1-5] are mitigated by costs [6] or confounded by ecological factors remains unexplored in the wild. We assessed novel problem-solving performance in 468 wild great tits Parus major temporarily taken into captivity and subsequently followed up their reproductive performance in the wild. Problem-solver females produced larger clutches than nonsolvers. This benefit did not arise because solvers timed their breeding better, occupied better habitats, or compromised offspring quality or their own survival. Instead, foraging range size and day length were relatively small and short, respectively, for solvers, suggesting that they were more efficient at exploiting their environment. In contrast to the positive effect on clutch size, problem solvers deserted their nests more often, leading to little or no overall selection on problem-solving performance. Our results are consistent with the idea that variation in cognitive ability is shaped by contrasting effects on different life history traits directly linked to fitness [1, 3]. PMID:22940473

  17. Centromere-associated meiotic drive and female fitness variation in Mimulus.

    PubMed

    Fishman, Lila; Kelly, John K

    2015-05-01

    Female meiotic drive, in which chromosomal variants preferentially segregate to the egg pole during asymmetric female meiosis, is a theoretically pervasive but still mysterious form of selfish evolution. Like other selfish genetic elements, driving chromosomes may be maintained as balanced polymorphisms by pleiotropic or linked fitness costs. A centromere-associated driver (D) with a ∼58:42 female-specific transmission advantage occurs at intermediate frequency (32-40%) in the Iron Mountain population of the yellow monkeyflower, Mimulus guttatus. Previously determined male fertility costs are sufficient to prevent the fixation of D, but predict a higher equilibrium frequency. To better understand the dynamics and effects of D, we developed a new population genetic model and measured genotype-specific lifetime female fitness in the wild. In three of four years, and across all years, D imposed significant recessive seedset costs, most likely due to hitchhiking by deleterious mutations. With both male and female costs as measured, and 58:42 drive, our model predicts an equilibrium frequency of D (38%) very close to the observed value. Thus, D represents a rare selfish genetic element whose local population genetic dynamics have been fully parameterized, and the observation of equilibrium sets the stage for investigations of coevolution with suppressors. PMID:25873401

  18. Spatial variation in the fitness of divergent aposematic phenotypes of the poison frog, Dendrobates tinctorius.

    PubMed

    Comeault, A A; Noonan, B P

    2011-06-01

    Aposematic species use brightly coloured signals to warn potential predators of their unpalatability. The function of these signals is largely believed to be frequency-dependent. All else being equal, stabilizing selection is expected to constrain the evolution of novel signals. However, despite the expected frequency-dependent function of aposematic signals, interpopulation variation in aposematic signals is ubiquitous in nature. Here, we used clay models of the poison frog Dendrobates tinctorius to test the nature of selection in regions containing varying frequencies of frogs possessing the local aposematic signal. Our findings support a role for stabilizing selection in maintaining the local signal type in a region of high signal frequency; however, we observe a lack of stabilizing selection at one site coincident with a decrease in the density of frogs possessing the local signal. Spatial variation in local aposematic signal frequencies may facilitate the evolution of novel signal types by altering the adaptive landscape for divergent aposematic phenotypes. Our results provide evidence for spatial variation in the selective regime acting on aposematic signals within an established aposematic system and highlight the need for further study of the nature of selection acting across different spatial scales in diverse aposematic systems. PMID:21418119

  19. Dissimilar Fitness Associated with Resistance to Fluoroquinolones Influences Clonal Dynamics of Various Multiresistant Bacteria

    PubMed Central

    Fuzi, Miklos

    2016-01-01

    Fitness cost associated with resistance to fluoroquinolones was recently shown to vary across clones of methicillin-resistant Staphylococcus aureus and extended-spectrum β-lactamase-producing Klebsiella pneumoniae. The resulting dissimilar fitness should have influenced the clonal dynamics and thereby the rates of resistance for these pathogens. Moreover, a similar mechanism was recently proposed for the emergence of the H30 and H30R lineages of ESBL-producing E. coli and the major international clone (ribotype 027) of Clostridium difficile. Furthermore, several additional international clones of various multiresistant bacteria are suspect to have been selected by an analogous process. An ability to develop favorable mutations in the gyrase and topoisomerase IV genes seems to be a prerequisite for pathogens to retain fitness while showing high-level resistance to fluoroquinolones. Since, the consumption of other “non-fluoroquinolone” groups of antibiotics have also contributed to the rise in resistance rates a more judicious use of antibiotics in general and of fluoroquinolones in particular could ameliorate the international resistance situation. PMID:27458434

  20. The influence of cardiorespiratory fitness on strategic, behavioral, and electrophysiological indices of arithmetic cognition in preadolescent children

    PubMed Central

    Moore, R. Davis; Drollette, Eric S.; Scudder, Mark R.; Bharij, Aashiv; Hillman, Charles H.

    2014-01-01

    The current study investigated the influence of cardiorespiratory fitness on arithmetic cognition in forty 9–10 year old children. Measures included a standardized mathematics achievement test to assess conceptual and computational knowledge, self-reported strategy selection, and an experimental arithmetic verification task (including small and large addition problems), which afforded the measurement of event-related brain potentials (ERPs). No differences in math achievement were observed as a function of fitness level, but all children performed better on math concepts relative to math computation. Higher fit children reported using retrieval more often to solve large arithmetic problems, relative to lower fit children. During the arithmetic verification task, higher fit children exhibited superior performance for large problems, as evidenced by greater d' scores, while all children exhibited decreased accuracy and longer reaction time for large relative to small problems, and incorrect relative to correct solutions. On the electrophysiological level, modulations of early (P1, N170) and late ERP components (P3, N400) were observed as a function of problem size and solution correctness. Higher fit children exhibited selective modulations for N170, P3, and N400 amplitude relative to lower fit children, suggesting that fitness influences symbolic encoding, attentional resource allocation and semantic processing during arithmetic tasks. The current study contributes to the fitness-cognition literature by demonstrating that the benefits of cardiorespiratory fitness extend to arithmetic cognition, which has important implications for the educational environment and the context of learning. PMID:24829556

  1. Consumer trait variation influences tritrophic interactions in salt marsh communities

    PubMed Central

    Hughes, Anne Randall; Hanley, Torrance C; Orozco, Nohelia P; Zerebecki, Robyn A

    2015-01-01

    The importance of intraspecific variation has emerged as a key question in community ecology, helping to bridge the gap between ecology and evolution. Although much of this work has focused on plant species, recent syntheses have highlighted the prevalence and potential importance of morphological, behavioral, and life history variation within animals for ecological and evolutionary processes. Many small-bodied consumers live on the plant that they consume, often resulting in host plant-associated trait variation within and across consumer species. Given the central position of consumer species within tritrophic food webs, such consumer trait variation may play a particularly important role in mediating trophic dynamics, including trophic cascades. In this study, we used a series of field surveys and laboratory experiments to document intraspecific trait variation in a key consumer species, the marsh periwinkle Littoraria irrorata, based on its host plant species (Spartina alterniflora or Juncus roemerianus) in a mixed species assemblage. We then conducted a 12-week mesocosm experiment to examine the effects of Littoraria trait variation on plant community structure and dynamics in a tritrophic salt marsh food web. Littoraria from different host plant species varied across a suite of morphological and behavioral traits. These consumer trait differences interacted with plant community composition and predator presence to affect overall plant stem height, as well as differentially alter the density and biomass of the two key plant species in this system. Whether due to genetic differences or phenotypic plasticity, trait differences between consumer types had significant ecological consequences for the tritrophic marsh food web over seasonal time scales. By altering the cascading effects of the top predator on plant community structure and dynamics, consumer differences may generate a feedback over longer time scales, which in turn influences the degree of trait

  2. Consumer trait variation influences tritrophic interactions in salt marsh communities.

    PubMed

    Hughes, Anne Randall; Hanley, Torrance C; Orozco, Nohelia P; Zerebecki, Robyn A

    2015-07-01

    The importance of intraspecific variation has emerged as a key question in community ecology, helping to bridge the gap between ecology and evolution. Although much of this work has focused on plant species, recent syntheses have highlighted the prevalence and potential importance of morphological, behavioral, and life history variation within animals for ecological and evolutionary processes. Many small-bodied consumers live on the plant that they consume, often resulting in host plant-associated trait variation within and across consumer species. Given the central position of consumer species within tritrophic food webs, such consumer trait variation may play a particularly important role in mediating trophic dynamics, including trophic cascades. In this study, we used a series of field surveys and laboratory experiments to document intraspecific trait variation in a key consumer species, the marsh periwinkle Littoraria irrorata, based on its host plant species (Spartina alterniflora or Juncus roemerianus) in a mixed species assemblage. We then conducted a 12-week mesocosm experiment to examine the effects of Littoraria trait variation on plant community structure and dynamics in a tritrophic salt marsh food web. Littoraria from different host plant species varied across a suite of morphological and behavioral traits. These consumer trait differences interacted with plant community composition and predator presence to affect overall plant stem height, as well as differentially alter the density and biomass of the two key plant species in this system. Whether due to genetic differences or phenotypic plasticity, trait differences between consumer types had significant ecological consequences for the tritrophic marsh food web over seasonal time scales. By altering the cascading effects of the top predator on plant community structure and dynamics, consumer differences may generate a feedback over longer time scales, which in turn influences the degree of trait

  3. One Size Does Not Fit All: Understanding the Variation in Charter Management Scale-Up

    ERIC Educational Resources Information Center

    Farrell, Caitlin; Nayfack, Michelle B.; Smith, Joanna; Wohlstetter, Priscilla

    2014-01-01

    The prevalence of charter management organizations (CMOs)--networks of charter schools overseen by a home office--has exploded in recent years but there is a paucity of research into how CMOs approach growth and the factors that influence their growth plans. In this qualitative study, we examine how a set of 25 older, more established CMOs…

  4. The Influence of Diet Composition on Fitness of the Blue Crab, Callinectes sapidus.

    PubMed

    Belgrad, Benjamin A; Griffen, Blaine D

    2016-01-01

    The physiological condition and fecundity of an organism is frequently controlled by diet. As changes in environmental conditions often cause organisms to alter their foraging behavior, a comprehensive understanding of how diet influences the fitness of an individual is central to predicting the effect of environmental change on population dynamics. We experimentally manipulated the diet of the economically and ecologically important blue crab, Callinectes sapidus, to approximate the effects of a dietary shift from primarily animal to plant tissue, a phenomenon commonly documented in crabs. Crabs whose diet consisted exclusively of animal tissue had markedly lower mortality and consumed substantially more food than crabs whose diet consisted exclusively of seaweed. The quantity of food consumed had a significant positive influence on reproductive effort and long-term energy stores. Additionally, seaweed diets produced a three-fold decrease in hepatopancreas lipid content and a simultaneous two-fold increase in crab aggression when compared to an animal diet. Our results reveal that the consumption of animal tissue substantially enhanced C. sapidus fitness, and suggest that a dietary shift to plant tissue may reduce crab population growth by decreasing fecundity as well as increasing mortality. This study has implications for C. sapidus fisheries.

  5. The Influence of Diet Composition on Fitness of the Blue Crab, Callinectes sapidus

    PubMed Central

    Belgrad, Benjamin A.; Griffen, Blaine D.

    2016-01-01

    The physiological condition and fecundity of an organism is frequently controlled by diet. As changes in environmental conditions often cause organisms to alter their foraging behavior, a comprehensive understanding of how diet influences the fitness of an individual is central to predicting the effect of environmental change on population dynamics. We experimentally manipulated the diet of the economically and ecologically important blue crab, Callinectes sapidus, to approximate the effects of a dietary shift from primarily animal to plant tissue, a phenomenon commonly documented in crabs. Crabs whose diet consisted exclusively of animal tissue had markedly lower mortality and consumed substantially more food than crabs whose diet consisted exclusively of seaweed. The quantity of food consumed had a significant positive influence on reproductive effort and long-term energy stores. Additionally, seaweed diets produced a three-fold decrease in hepatopancreas lipid content and a simultaneous two-fold increase in crab aggression when compared to an animal diet. Our results reveal that the consumption of animal tissue substantially enhanced C. sapidus fitness, and suggest that a dietary shift to plant tissue may reduce crab population growth by decreasing fecundity as well as increasing mortality. This study has implications for C. sapidus fisheries. PMID:26784581

  6. Phenotypic Variation and Fitness in a Metapopulation of Tubeworms (Ridgeia piscesae Jones) at Hydrothermal Vents

    PubMed Central

    Tunnicliffe, Verena; St. Germain, Candice; Hilário, Ana

    2014-01-01

    We examine the nature of variation in a hot vent tubeworm, Ridgeia piscesae, to determine how phenotypes are maintained and how reproductive potential is dictated by habitat. This foundation species at northeast Pacific hydrothermal sites occupies a wide habitat range in a highly heterogeneous environment. Where fluids supply high levels of dissolved sulphide for symbionts, the worm grows rapidly in a “short-fat” phenotype characterized by lush gill plumes; when plumes are healthy, sperm package capture is higher. This form can mature within months and has a high fecundity with continuous gamete output and a lifespan of about three years in unstable conditions. Other phenotypes occupy low fluid flux habitats that are more stable and individuals grow very slowly; however, they have low reproductive readiness that is hampered further by small, predator cropped branchiae, thus reducing fertilization and metabolite uptake. Although only the largest worms were measured, only 17% of low flux worms were reproductively competent compared to 91% of high flux worms. A model of reproductive readiness illustrates that tube diameter is a good predictor of reproductive output and that few low flux worms reached critical reproductive size. We postulate that most of the propagules for the vent fields originate from the larger tubeworms that live in small, unstable habitat patches. The large expanses of worms in more stable low flux habitat sustain a small, but long-term, reproductive output. Phenotypic variation is an adaptation that fosters both morphological and physiological responses to differences in chemical milieu and predator pressure. This foundation species forms a metapopulation with variable growth characteristics in a heterogeneous environment where a strategy of phenotypic variation bestows an advantage over specialization. PMID:25337895

  7. Phenotypic variation and fitness in a metapopulation of tubeworms (Ridgeia piscesae Jones) at hydrothermal vents.

    PubMed

    Tunnicliffe, Verena; St Germain, Candice; Hilário, Ana

    2014-01-01

    We examine the nature of variation in a hot vent tubeworm, Ridgeia piscesae, to determine how phenotypes are maintained and how reproductive potential is dictated by habitat. This foundation species at northeast Pacific hydrothermal sites occupies a wide habitat range in a highly heterogeneous environment. Where fluids supply high levels of dissolved sulphide for symbionts, the worm grows rapidly in a "short-fat" phenotype characterized by lush gill plumes; when plumes are healthy, sperm package capture is higher. This form can mature within months and has a high fecundity with continuous gamete output and a lifespan of about three years in unstable conditions. Other phenotypes occupy low fluid flux habitats that are more stable and individuals grow very slowly; however, they have low reproductive readiness that is hampered further by small, predator cropped branchiae, thus reducing fertilization and metabolite uptake. Although only the largest worms were measured, only 17% of low flux worms were reproductively competent compared to 91% of high flux worms. A model of reproductive readiness illustrates that tube diameter is a good predictor of reproductive output and that few low flux worms reached critical reproductive size. We postulate that most of the propagules for the vent fields originate from the larger tubeworms that live in small, unstable habitat patches. The large expanses of worms in more stable low flux habitat sustain a small, but long-term, reproductive output. Phenotypic variation is an adaptation that fosters both morphological and physiological responses to differences in chemical milieu and predator pressure. This foundation species forms a metapopulation with variable growth characteristics in a heterogeneous environment where a strategy of phenotypic variation bestows an advantage over specialization.

  8. Parasite fitness traits under environmental variation: disentangling the roles of a chytrid's immediate host and external environment.

    PubMed

    Van den Wyngaert, Silke; Vanholsbeeck, Olivier; Spaak, Piet; Ibelings, Bas W

    2014-10-01

    Parasite environments are heterogeneous at different levels. The first level of variability is the host itself. The second level represents the external environment for the hosts, to which parasites may be exposed during part of their life cycle. Both levels are expected to affect parasite fitness traits. We disentangle the main and interaction effects of variation in the immediate host environment, here the diatom Asterionella formosa (variables host cell volume and host condition through herbicide pre-exposure) and variation in the external environment (variables host density and acute herbicide exposure) on three fitness traits (infection success, development time and reproductive output) of a chytrid parasite. Herbicide exposure only decreased infection success in a low host density environment. This result reinforces the hypothesis that chytrid zoospores use photosynthesis-dependent chemical cues to locate its host. At high host densities, chemotaxis becomes less relevant due to increasing chance contact rates between host and parasite, thereby following the mass-action principle in epidemiology. Theoretical support for this finding is provided by an agent-based simulation model. The immediate host environment (cell volume) substantially affected parasite reproductive output and also interacted with the external herbicide exposed environment. On the contrary, changes in the immediate host environment through herbicide pre-exposure did not increase infection success, though it had subtle effects on zoospore development time and reproductive output. This study shows that both immediate host and external environment as well as their interaction have significant effects on parasite fitness. Disentangling these effects improves our understanding of the processes underlying parasite spread and disease dynamics.

  9. Better stay together: pair bond duration increases individual fitness independent of age-related variation

    PubMed Central

    Sánchez-Macouzet, Oscar; Rodríguez, Cristina; Drummond, Hugh

    2014-01-01

    Prolonged pair bonds have the potential to improve reproductive performance of socially monogamous animals by increasing pair familiarity and enhancing coordination and cooperation between pair members. However, this has proved very difficult to test robustly because of important confounds such as age and reproductive experience. Here, we address limitations of previous studies and provide a rigorous test of the mate familiarity effect in the socially monogamous blue-footed booby, Sula nebouxii, a long-lived marine bird with a high divorce rate. Taking advantage of a natural disassociation between age and pair bond duration in this species, and applying a novel analytical approach to a 24 year database, we found that those pairs which have been together for longer establish their clutches five weeks earlier in the season, hatch more of their eggs and produce 35% more fledglings, regardless of age and reproductive experience. Our results demonstrate that pair bond duration increases individual fitness and further suggest that synergistic effects between a male and female's behaviour are likely to be involved in generating a mate familiarity effect. These findings help to explain the age- and experience-independent benefits of remating and their role in life-history evolution. PMID:24827435

  10. Better stay together: pair bond duration increases individual fitness independent of age-related variation.

    PubMed

    Sánchez-Macouzet, Oscar; Rodríguez, Cristina; Drummond, Hugh

    2014-07-01

    Prolonged pair bonds have the potential to improve reproductive performance of socially monogamous animals by increasing pair familiarity and enhancing coordination and cooperation between pair members. However, this has proved very difficult to test robustly because of important confounds such as age and reproductive experience. Here, we address limitations of previous studies and provide a rigorous test of the mate familiarity effect in the socially monogamous blue-footed booby, Sula nebouxii, a long-lived marine bird with a high divorce rate. Taking advantage of a natural disassociation between age and pair bond duration in this species, and applying a novel analytical approach to a 24 year database, we found that those pairs which have been together for longer establish their clutches five weeks earlier in the season, hatch more of their eggs and produce 35% more fledglings, regardless of age and reproductive experience. Our results demonstrate that pair bond duration increases individual fitness and further suggest that synergistic effects between a male and female's behaviour are likely to be involved in generating a mate familiarity effect. These findings help to explain the age- and experience-independent benefits of remating and their role in life-history evolution.

  11. Better stay together: pair bond duration increases individual fitness independent of age-related variation.

    PubMed

    Sánchez-Macouzet, Oscar; Rodríguez, Cristina; Drummond, Hugh

    2014-07-01

    Prolonged pair bonds have the potential to improve reproductive performance of socially monogamous animals by increasing pair familiarity and enhancing coordination and cooperation between pair members. However, this has proved very difficult to test robustly because of important confounds such as age and reproductive experience. Here, we address limitations of previous studies and provide a rigorous test of the mate familiarity effect in the socially monogamous blue-footed booby, Sula nebouxii, a long-lived marine bird with a high divorce rate. Taking advantage of a natural disassociation between age and pair bond duration in this species, and applying a novel analytical approach to a 24 year database, we found that those pairs which have been together for longer establish their clutches five weeks earlier in the season, hatch more of their eggs and produce 35% more fledglings, regardless of age and reproductive experience. Our results demonstrate that pair bond duration increases individual fitness and further suggest that synergistic effects between a male and female's behaviour are likely to be involved in generating a mate familiarity effect. These findings help to explain the age- and experience-independent benefits of remating and their role in life-history evolution. PMID:24827435

  12. Fitness consequences of natural variation in flooding-induced shoot elongation in Rumex palustris.

    PubMed

    Chen, Xin; Visser, Eric J W; de Kroon, Hans; Pierik, Ronald; Voesenek, Laurentius A C J; Huber, Heidrun

    2011-04-01

    • Plants can respond to their environment by morphological plasticity. Generally, the potential benefits of adaptive plastic responses are beyond doubt under predictable environmental changes. However, the net benefits may be less straightforward when plants encounter temporal stresses, such as flooding in river flood plains. • Here, we tested whether the balance of costs and benefits associated with flooding-induced shoot elongation depends on the flooding regime, by subjecting Rumex palustris plants with different elongation capacity to submergence of different frequency and duration. • Our results showed that reaching the surface by shoot elongation is associated with fitness benefits, as under less frequent, but longer, flooding episodes plants emerging above the floodwater had greater biomass production than plants that were kept below the surface. As we predicted, slow-elongating plants had clear advantages over fast-elongating ones if submergence was frequent but of short duration, indicating that elongation also incurs costs. • Our data suggest that high costs select for weak plasticity under frequent environmental change. In contrast to our predictions, however, fast-elongating plants did not have an overall advantage over slow-elongating plants when floods lasted longer. This indicates that the delicate balance between benefits and costs of flooding-induced elongation depends on the specific characteristics of the flooding regime.

  13. Spatiotemporal Variation in Distance Dependent Animal Movement Contacts: One Size Doesn’t Fit All

    PubMed Central

    Brommesson, Peter; Wennergren, Uno; Lindström, Tom

    2016-01-01

    The structure of contacts that mediate transmission has a pronounced effect on the outbreak dynamics of infectious disease and simulation models are powerful tools to inform policy decisions. Most simulation models of livestock disease spread rely to some degree on predictions of animal movement between holdings. Typically, movements are more common between nearby farms than between those located far away from each other. Here, we assessed spatiotemporal variation in such distance dependence of animal movement contacts from an epidemiological perspective. We evaluated and compared nine statistical models, applied to Swedish movement data from 2008. The models differed in at what level (if at all), they accounted for regional and/or seasonal heterogeneities in the distance dependence of the contacts. Using a kernel approach to describe how probability of contacts between farms changes with distance, we developed a hierarchical Bayesian framework and estimated parameters by using Markov Chain Monte Carlo techniques. We evaluated models by three different approaches of model selection. First, we used Deviance Information Criterion to evaluate their performance relative to each other. Secondly, we estimated the log predictive posterior distribution, this was also used to evaluate their relative performance. Thirdly, we performed posterior predictive checks by simulating movements with each of the parameterized models and evaluated their ability to recapture relevant summary statistics. Independent of selection criteria, we found that accounting for regional heterogeneity improved model accuracy. We also found that accounting for seasonal heterogeneity was beneficial, in terms of model accuracy, according to two of three methods used for model selection. Our results have important implications for livestock disease spread models where movement is an important risk factor for between farm transmission. We argue that modelers should refrain from using methods to simulate

  14. Variation potential influence on photosynthetic cyclic electron flow in pea

    PubMed Central

    Sukhov, Vladimir; Surova, Lyubov; Sherstneva, Oksana; Katicheva, Lyubov; Vodeneev, Vladimir

    2015-01-01

    Cyclic electron flow is an important component of the total photosynthetic electron flow and participates in adaptation to the action of stressors. Local leaf stimulation induces electrical signals, including variation potential (VP), which inactivate photosynthesis; however, their influence on cyclic electron flow has not been investigated. The aim of this study was to investigate VP's influence on cyclic electron flow in pea (Pisum sativum L.). VP was induced in pea seedling leaves by local heating and measured in an adjacent, undamaged leaf by extracellular electrodes. CO2 assimilation was measured using a portable gas exchange measuring system. Photosystem I and II parameters were investigated using a measuring system for simultaneous assessment of P700 oxidation and chlorophyll fluorescence. Heating-induced VP reduced CO2 assimilation and electron flow through photosystem II. In response, cyclic electron flow rapidly decreased and subsequently slowly increased. Slow increases in cyclic flow were caused by decreased electron flow through photosystem II, which was mainly connected with VP-induced photosynthetic dark stage inactivation. However, direct influence by VP on photosystem I also participated in activation of cyclic electron flow. Thus, VP, induced by local leaf-heating, activated cyclic electron flow in undamaged leaves. This response was similar to photosynthetic changes observed under the direct action of stressors. Possible mechanisms of VP's influence on cyclic flow were discussed. PMID:25610447

  15. One number does not fit all: mapping local variations in resolution in cryo-EM reconstructions

    PubMed Central

    Cardone, Giovanni; Heymann, J. Bernard; Steven, Alasdair C.

    2013-01-01

    The resolution of density maps from single particle analysis is usually measured in terms of the highest spatial frequency to which consistent information has been obtained. This calculation represents an average over the entire reconstructed volume. In practice, however, substantial local variations in resolution may occur, either from intrinsic properties of the specimen or for technical reasons such as a non-isotropic distribution of viewing orientations. To address this issue, we propose the use of a space-frequency representation, the short-space Fourier transform, to assess the quality of a density map, voxel-by-voxel, i.e. by local resolution mapping. In this approach, the experimental volume is divided into small subvolumes and the resolution determined for each of them. It is illustrated in applications both to model data and to experimental density maps. Regions with lower-than-average resolution may be mobile components or ones with incomplete occupancy or result from multiple conformational states. To improve the interpretability of reconstructions, we propose an adaptive filtering approach that reconciles the resolution to which individual features are calculated with the results of the local resolution map. PMID:23954653

  16. The Influence of Functional Fitness and Cognitive Training of Physical Disabilities of Institutions

    PubMed Central

    Yeh, I-Chen; Chang, Chia-Ming; Chen, Ko-Chia; Hong, Wei-Chin; Lu, Yu-Hsiung

    2015-01-01

    According to an investigation done by Taiwan Ministry of the Interior in 2013, there was more than 90% of the disability care institutions mainly based on life care. Previous studies have shown that individuals can effectively improve physical and cognitive training, improved in independent living and everyday competence. The purpose of the study was to investigate influence of the intervention program applying functional fitness and cognitive training to disabled residents in the institution. The subjects were disabled persons of a care institution in southern Taiwan and were randomly divided into training and control groups, both having 17 subjects. The age of the subjects was between 56 and 98 years with a mean age of 79.08 ± 10.04 years; the subjects of training group implemented 12 weeks of training on physical and cognitive training, while the control group subjects did not have any training program. The results revealed that subjects of the training group have significantly improved their functional shoulder rotation flexibility of left and right anterior hip muscle group flexibility of right, sitting functional balance of left and right, naming, attention, delayed recall, orientation, and Montreal cognitive assessment (MOCA). The study suggested developing physical fitness programs and physical and cognitive prescriptions for the disabled people of the institutions. PMID:25756064

  17. Influence of diet and/or exercise on body composition and cardiorespiratory fitness in obese women.

    PubMed

    Utter, A C; Nieman, D C; Shannonhouse, E M; Butterworth, D E; Nieman, C N

    1998-09-01

    The purpose of this study was to measure the influence of diet, exercise, or both on body composition and cardiorespiratory fitness in obese women. Ninety-one obese subjects were randomized into one of four groups: diet (D) (4.19-5.44 MJ or 1,200-1,300 kcal/day), exercise (E) (five 45-min sessions at 78.5+/-0.5% maximum heart rate), exercise and diet (ED), and controls (C). Maximal aerobic power and body composition were measured in all subjects before and after a 12-week diet intervention period. Subjects in D and ED lost 7.8+/-0.7 and 8.1+/-0.6 kg body mass, with no significant change for E relative to C. Losses of percent body fat and fat mass were significantly greater in D and ED but not in E relative to C. The change in VO2max was greater in ED and E but not D when compared to C. Results indicate that moderate aerobic exercise training during a 12-week period has no discernible effects on body composition but does improve cardiorespiratory fitness in dieting obese women.

  18. Adrenocortical stress responses influence an invasive vertebrate's fitness in an extreme environment

    PubMed Central

    Jessop, Tim S.; Letnic, Mike; Webb, Jonathan K.; Dempster, Tim

    2013-01-01

    Continued range expansion into physiologically challenging environments requires invasive species to maintain adaptive phenotypic performance. The adrenocortical stress response, governed in part by glucocorticoid hormones, influences physiological and behavioural responses of vertebrates to environmental stressors. However, any adaptive role of this response in invasive populations that are expanding into extreme environments is currently unclear. We experimentally manipulated the adrenocortical stress response of invasive cane toads (Rhinella marina) to investigate its effect on phenotypic performance and fitness at the species' range front in the Tanami Desert, Australia. Here, toads are vulnerable to overheating and dehydration during the annual hot–dry season and display elevated plasma corticosterone levels indicative of severe environmental stress. By comparing unmanipulated control toads with toads whose adrenocortical stress response was manipulated to increase acute physiological stress responsiveness, we found that control toads had significantly reduced daily evaporative water loss and higher survival relative to the experimental animals. The adrenocortical stress response hence appears essential in facilitating complex phenotypic performance and setting fitness trajectories of individuals from invasive species during range expansion. PMID:23945686

  19. A review of body image influences on men's fitness goals and supplement use.

    PubMed

    McCreary, Donald R; Hildebrandt, Thomas B; Heinberg, Leslie J; Boroughs, Michael; Thompson, J Kevin

    2007-12-01

    Men's fitness goals are influenced by the lens through which they view their bodies, which is different from the way women view their bodies. Their increased focus on a muscular, hairless body means that they exercise to enhance their physical bulk and are more likely to engage in depilatory behaviors. In addition, the drive for muscularity may be associated with an increased risk anabolic-androgenic steroids and other nutritional supplements whose utility not clearly demonstrated. In the extreme, the drive for muscularity may manifest itself as a form of body dysmorphic disorder referred to as muscle dysmorphia. However, not all men focus on their muscularity. Gay men are more likely than heterosexual men to experience a desire to be thin and are at greater risk for eating and body image disorders. These issues are discussed in this article. PMID:19482812

  20. The influence of motivation on stress: is it stressful not to fit?

    PubMed

    Schwab, Sebastian; Wolf, Oliver T; Memmert, Daniel

    2015-01-01

    The present research elaborates on the regulatory fit hypothesis by investigating a biological stress marker in a motivational fit- and non-fit-situation. Recent stress theories lead to the assumption that the participants' stress level in fit-situations remains constant or rather decreases, whereas under non-fit-conditions an increase of the stress activity is observed. We tested this hypothesis by assessment of salivary α-amylase (sAA), a saliva-based stress marker presumed to reflect noradrenergic activity. The results indicated that participants in a fit-situation show a decrease in sAA, whereas participants in a non-fit-situation demonstrate a contrary effect with an increase in sAA. These findings extend the concept of regulatory fit by illustrating that there are differences in sAA activity depending on whether participants are in a fit-situation. The experience of regulatory fit appears to be associated with a reduction of stress.

  1. Heat shock protein 101 effects in A. thaliana: genetic variation, fitness and pleiotropy in controlled temperature conditions

    PubMed Central

    TONSOR, S. J.; SCOTT, C.; BOUMAZA, I.; LISS, T. R.; BRODSKY, J. L.; VIERLING, E.

    2009-01-01

    The Hsp100/ClpB heat shock protein family is ancient and required for high temperature survival, but natural variation in expression and its phenotypic effects is unexplored in plants. In controlled environment experiments, we examined the effects of variation in the Arabidopsis cytosolic AtHsp101 (hereafter Hsp101). Ten wild-collected ecotypes differed in Hsp101 expression responses across a 22 to 40 °C gradient. Genotypes from low latitudes expressed the least Hsp101. We tested fitness and pleiotropic consequences of varying Hsp101 expression in ‘control’ vs. mild thermal stress treatments (15/25 °C D/N vs. 15/25° D/N plus 3 h at 35 °C 3 days/week). Comparing wild type and null mutants, wt Columbia (Col) produced ~33% more fruits compared to its Hsp101 homozygous null mutant. There was no difference between Landsberg erecta null mutant NIL (Ler) and wt Ler; wt Ler showed very low Hsp101 expression. In an assay of six genotypes, fecundity was a saturating function of Hsp101 content, in both experimental treatments. Thus, in addition to its essential role in acquired thermal tolerance, Hsp101 provides a substantial fitness benefit under normal growth conditions. Knocking out Hsp101 decreased fruit production, days to germination and days to bolting, total dry mass, and number of inflorescences; it increased transpiration rate and allocation to root mass. Root : total mass ratio decayed exponentially with Hsp101 content. This study shows that Hsp101 expression is evolvable in natural populations. Our results further suggest that Hsp101 is primarily an emergency high-temperature tolerance mechanism, since expression levels are lower in low-latitude populations from warmer climates. Hsp101 expression appears to carry an important trade-off in reduced root growth. This trade-off may select for suppressed expression under chronically high temperatures. PMID:18321256

  2. Extreme variation in migration strategies between and within wandering albatross populations during their sabbatical year, and their fitness consequences.

    PubMed

    Weimerskirch, Henri; Delord, Karine; Guitteaud, Audrey; Phillips, Richard A; Pinet, Patrick

    2015-01-01

    Migratory behavior, routes and zones used during the non-breeding season are assumed to have been selected to maximize fitness, and can lead to genetic differentiation. Yet, here we show that migration strategies differ markedly between and within two genetically similar populations of wandering albatross Diomedea exulans from the Crozet and Kerguelen archipelagos in the Indian Ocean. Wandering albatrosses usually breed biennially if successful, and during the sabbatical year, all birds from Kerguelen migrate to the Pacific Ocean, whereas most from Crozet are sedentary. Instead of taking the shortest routes, which would involve a return against headwinds, migratory birds fly with the westerly winds, requiring detours of 10,000 s km. In total, migrants circumnavigate Antarctica 2 to 3 times, covering more than 120,000 km in a single sabbatical year. Our results indicate strong links between migratory behavior and fitness; all birds from Kerguelen breed biennially, whereas a significant proportion of those from Crozet, especially females, are sedentary and breed in consecutive calendar years. To breed annually, these females temporarily change mate, but return to their original partner in the following year. This extreme variation in migratory behavior has important consequences in term of life history evolution and susceptibility to climate change and fisheries. PMID:25747757

  3. Extreme variation in migration strategies between and within wandering albatross populations during their sabbatical year, and their fitness consequences

    PubMed Central

    Weimerskirch, Henri; Delord, Karine; Guitteaud, Audrey; Phillips, Richard A.; Pinet, Patrick

    2015-01-01

    Migratory behavior, routes and zones used during the non-breeding season are assumed to have been selected to maximize fitness, and can lead to genetic differentiation. Yet, here we show that migration strategies differ markedly between and within two genetically similar populations of wandering albatross Diomedea exulans from the Crozet and Kerguelen archipelagos in the Indian Ocean. Wandering albatrosses usually breed biennially if successful, and during the sabbatical year, all birds from Kerguelen migrate to the Pacific Ocean, whereas most from Crozet are sedentary. Instead of taking the shortest routes, which would involve a return against headwinds, migratory birds fly with the westerly winds, requiring detours of 10,000 s km. In total, migrants circumnavigate Antarctica 2 to 3 times, covering more than 120,000 km in a single sabbatical year. Our results indicate strong links between migratory behavior and fitness; all birds from Kerguelen breed biennially, whereas a significant proportion of those from Crozet, especially females, are sedentary and breed in consecutive calendar years. To breed annually, these females temporarily change mate, but return to their original partner in the following year. This extreme variation in migratory behavior has important consequences in term of life history evolution and susceptibility to climate change and fisheries. PMID:25747757

  4. Genetic variation in BEACON influences quantitative variation in metabolic syndrome-related phenotypes.

    PubMed

    Jowett, Jeremy B; Elliott, Kate S; Curran, Joanne E; Hunt, Nicola; Walder, Ken R; Collier, Greg R; Zimmet, Paul Z; Blangero, John

    2004-09-01

    The BEACON gene (also known as UBL5) was identified as differentially expressed between lean and obese Psammomys obesus, a polygenic animal model of obesity, type 2 diabetes, and dyslipidemia. The human homologue of BEACON is located on chromosome 19p, a region likely to contain genes affecting metabolic syndrome-related quantitative traits as established by linkage studies. To assess whether the human BEACON gene may be involved in influencing these traits, we exhaustively analyzed the complete gene for genetic variation in 40 unrelated individuals and identified four variants (three novel). The two more common variants were tested for association with a number of quantitative metabolic syndrome-related traits in two large cohorts of unrelated individuals. Significant associations were found between these variants and fat mass (P = 0.026), percentage of fat (P = 0.001), and waist-to-hip ratio (P = 0.031). The same variants were also associated with total cholesterol (P = 0.024), LDL cholesterol (P = 0.019), triglycerides (P = 0.006), and postglucose load insulin levels (P = 0.018). Multivariate analysis of these correlated phenotypes also yielded a highly significant association (P = 0.0004), suggesting that BEACON may influence phenotypic variation in metabolic syndrome-related traits.

  5. Interspecific competition influences fitness benefits of assortative mating for territorial aggression in eastern bluebirds (Sialia sialis).

    PubMed

    Harris, Morgan R; Siefferman, Lynn

    2014-01-01

    Territorial aggression influences fitness and, in monogamous pairs, the behavior of both individuals could impact reproductive success. Moreover, territorial aggression is particularly important in the context of interspecific competition. Tree swallows and eastern bluebirds are highly aggressive, secondary cavity-nesting birds that compete for limited nesting sites. We studied eastern bluebirds at a field site in the southern Appalachian Mountains that has been recently colonized (<40 yr) by tree swallows undergoing a natural range expansion. The field site is composed of distinct areas where bluebirds compete regularly with tree swallows and areas where there is little interaction between the two species. Once birds had settled, we measured how interspecific competition affects the relationship between assortative mating (paired individuals that behave similarly) and reproductive success in eastern bluebirds. We found a strong tendency toward assortative mating throughout the field site. In areas of high interspecific competition, pairs that behaved the most similarly and displayed either extremely aggressive or extremely non-aggressive phenotypes experienced higher reproductive success. Our data suggest that interspecific competition with tree swallows may select for bluebirds that express similar behavior to that of their mate. Furthermore, animal personality may be an important factor influencing the outcome of interactions between native and aggressive, invasive species. PMID:24516672

  6. Influence of cardiorespiratory fitness on PPARG mRNA expression using monozygotic twin case control.

    PubMed

    Queiroga, Marcos Roberto; Barbieri, Ricardo Augusto; Ferreira, Sandra Aires; Luchessi, André Ducati; Hirata, Rosario Dominguez Crespo; Hirata, Mario Hiroyuki; Kokubun, Eduardo

    2015-01-01

    The influence of cardiorespiratory fitness (VO2max) on anthropometric variables and PPARG mRNA expression was investigated. Monozygotic twin pairs aged 11-18 years were grouped into discordant (D) and concordant (C) high and low VO2max groups. VO2max was determined by progressive maximal exercise test on treadmill with gas exchange analysis. Body mass (BM), BMI, waist circumference (WC), triceps (TR), and subscapular (SB) skinfold thicknesses were measured. Twins from the discordant group had differences in VO2max values (D-high = 45.9 ± 10.0 versus D-low = 32.4 ± 10.6 mL·kg(-1)·min(-1), P = 0.025), while no differences were found in the concordant group (C-high = 42.4 ± 9.2 versus C-low = 38.8 ± 9.8 mL·kg(-1)·min(-1), P = 0.952). In discordant group, VO2max was negatively correlated with TR + SB (r = -0.540, P = 0.021) and positively correlated with PPARG expression in leukocytes (r = 0.952, P = 0.001). Moreover, PPARG expression was directly correlated with BM (r = 0.714, P = 0.047) and height (r = 0.762, P = 0.028). In concordant twins, VO2max was inversely correlated with BM (r = -0.290, P = 0.027), BMI (r = -0.472, P = 0.001), WC (r = -0.426, P = 0.001), and TR + SB (r = -0.739, P = 0.001). Twins D-high had 1.78-fold greater PPARG expression when compared with twins D-low (P = 0.048). In conclusion, the cardiorespiratory fitness may modulate PPARG expression in childhood and adolescence, independently of the genetic background. PMID:25879043

  7. Influence of Cardiorespiratory Fitness on PPARG mRNA Expression Using Monozygotic Twin Case Control

    PubMed Central

    Queiroga, Marcos Roberto; Barbieri, Ricardo Augusto; Ferreira, Sandra Aires; Luchessi, André Ducati; Hirata, Rosario Dominguez Crespo; Hirata, Mario Hiroyuki; Kokubun, Eduardo

    2015-01-01

    The influence of cardiorespiratory fitness (VO2max) on anthropometric variables and PPARG mRNA expression was investigated. Monozygotic twin pairs aged 11–18 years were grouped into discordant (D) and concordant (C) high and low VO2max groups. VO2max was determined by progressive maximal exercise test on treadmill with gas exchange analysis. Body mass (BM), BMI, waist circumference (WC), triceps (TR), and subscapular (SB) skinfold thicknesses were measured. Twins from the discordant group had differences in VO2max values (D-high = 45.9 ± 10.0 versus D-low = 32.4 ± 10.6 mL·kg−1·min−1, P = 0.025), while no differences were found in the concordant group (C-high = 42.4 ± 9.2 versus C-low = 38.8 ± 9.8 mL·kg−1·min−1, P = 0.952). In discordant group, VO2max was negatively correlated with TR + SB (r = −0.540, P = 0.021) and positively correlated with PPARG expression in leukocytes (r = 0.952, P = 0.001). Moreover, PPARG expression was directly correlated with BM (r = 0.714, P = 0.047) and height (r = 0.762, P = 0.028). In concordant twins, VO2max was inversely correlated with BM (r = −0.290, P = 0.027), BMI (r = −0.472, P = 0.001), WC (r = −0.426, P = 0.001), and TR + SB (r = −0.739, P = 0.001). Twins D-high had 1.78-fold greater PPARG expression when compared with twins D-low (P = 0.048). In conclusion, the cardiorespiratory fitness may modulate PPARG expression in childhood and adolescence, independently of the genetic background. PMID:25879043

  8. Influence of megapolis on the physical field variations

    NASA Astrophysics Data System (ADS)

    Riabova, Svetlana; Loktev, Dmitry; Spivak, Alexander

    2016-04-01

    The research of geophysical fields in the conditions of megapolis attracts particular interest not only in terms of their influence on the operation of precision equipment and technological processes associated with nanotechnology, but also it is perhaps the most important in terms of the formation of a special human and other biological objects' habitat. Indeed, the megapolis causes significant changes in regime of the physical fields both directly and indirectly. Negative factors of megapolis associated with elevated vibrations of soil as a result of traffic, acoustic load in the construction of infrastructure and transport communications, etc. are complemented by another negative factor, which until quite recently wasn't known much. It is a variation of physical fields (primarily electric and magnetic) induced by anthropogenic activities. As a result of the evolution a man has adapted to the natural regime of physical fields. Therefore, any, even the short-term changes of physical fields in the environment, their deviations from the natural rate can have a significant influence on human health including changes in the psycho-emotional state. In the present work we have evaluated the influence of the megapolis (in our case, Moscow) on the nature and regime of microseismic, electric and acoustic field in the surface atmosphere. We have analyzed data obtained as a result of continuous simultaneous registration of physical fields and meteorological parameters at the Center for geophysical monitoring of Moscow of Institute of Geosphere Dynamics of Russian Academy of Sciences. For determination of the characteristics of physical fields in the megapolis obtained data were compared with the results of the registration carried out at the Geophysical Observatory "Mikhnevo" of IDG RAS (located 85 km south from Moscow). The work is shown that the influence of the megapolis appears to increase the amplitude of physical fields, change of their spectral composition

  9. Different CAD/CAM-processing routes for zirconia restorations: influence on fitting accuracy.

    PubMed

    Kohorst, Philipp; Junghanns, Janet; Dittmer, Marc P; Borchers, Lothar; Stiesch, Meike

    2011-08-01

    The aim of the present in vitro study was to evaluate the influence of different processing routes on the fitting accuracy of four-unit zirconia fixed dental prostheses (FDPs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM). Three groups of zirconia frameworks with ten specimens each were fabricated. Frameworks of one group (CerconCAM) were produced by means of a laboratory CAM-only system. The other frameworks were made with different CAD/CAM systems; on the one hand by in-laboratory production (CerconCAD/CAM) and on the other hand by centralized production in a milling center (Compartis) after forwarding geometrical data. Frameworks were then veneered with the recommended ceramics, and marginal accuracy was determined using a replica technique. Horizontal marginal discrepancy, vertical marginal discrepancy, absolute marginal discrepancy, and marginal gap were evaluated. Statistical analyses were performed by one-way analysis of variance (ANOVA), with the level of significance chosen at 0.05. Mean horizontal discrepancies ranged between 22 μm (CerconCAM) and 58 μm (Compartis), vertical discrepancies ranged between 63 μm (CerconCAD/CAM) and 162 μm (CerconCAM), and absolute marginal discrepancies ranged between 94 μm (CerconCAD/CAM) and 181 μm (CerconCAM). The marginal gap varied between 72 μm (CerconCAD/CAM) and 112 μm (CerconCAM, Compartis). Statistical analysis revealed that, with all measurements, the marginal accuracy of the zirconia FDPs was significantly influenced by the processing route used (p < 0.05). Within the limitations of this study, all restorations showed a clinically acceptable marginal accuracy; however, the results suggest that the CAD/CAM systems are more precise than the CAM-only system for the manufacture of four-unit FDPs. PMID:20495937

  10. Different CAD/CAM-processing routes for zirconia restorations: influence on fitting accuracy.

    PubMed

    Kohorst, Philipp; Junghanns, Janet; Dittmer, Marc P; Borchers, Lothar; Stiesch, Meike

    2011-08-01

    The aim of the present in vitro study was to evaluate the influence of different processing routes on the fitting accuracy of four-unit zirconia fixed dental prostheses (FDPs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM). Three groups of zirconia frameworks with ten specimens each were fabricated. Frameworks of one group (CerconCAM) were produced by means of a laboratory CAM-only system. The other frameworks were made with different CAD/CAM systems; on the one hand by in-laboratory production (CerconCAD/CAM) and on the other hand by centralized production in a milling center (Compartis) after forwarding geometrical data. Frameworks were then veneered with the recommended ceramics, and marginal accuracy was determined using a replica technique. Horizontal marginal discrepancy, vertical marginal discrepancy, absolute marginal discrepancy, and marginal gap were evaluated. Statistical analyses were performed by one-way analysis of variance (ANOVA), with the level of significance chosen at 0.05. Mean horizontal discrepancies ranged between 22 μm (CerconCAM) and 58 μm (Compartis), vertical discrepancies ranged between 63 μm (CerconCAD/CAM) and 162 μm (CerconCAM), and absolute marginal discrepancies ranged between 94 μm (CerconCAD/CAM) and 181 μm (CerconCAM). The marginal gap varied between 72 μm (CerconCAD/CAM) and 112 μm (CerconCAM, Compartis). Statistical analysis revealed that, with all measurements, the marginal accuracy of the zirconia FDPs was significantly influenced by the processing route used (p < 0.05). Within the limitations of this study, all restorations showed a clinically acceptable marginal accuracy; however, the results suggest that the CAD/CAM systems are more precise than the CAM-only system for the manufacture of four-unit FDPs.

  11. Influence of mutation and recombination on HIV-1 in vitro fitness recovery.

    PubMed

    Arenas, Miguel; Lorenzo-Redondo, Ramon; Lopez-Galindez, Cecilio

    2016-01-01

    The understanding of the evolutionary processes underlying HIV-1 fitness recovery is fundamental for HIV-1 pathogenesis, antiretroviral treatment and vaccine design. It is known that HIV-1 can present very high mutation and recombination rates, however the specific contribution of these evolutionary forces in the "in vitro" viral fitness recovery has not been simultaneously quantified. To this aim, we analyzed substitution, recombination and molecular adaptation rates in a variety of HIV-1 biological clones derived from a viral isolate after severe population bottlenecks and a number of large population cell culture passages. These clones presented an overall but uneven fitness gain, mean of 3-fold, respect to the initial passage values. We found a significant relationship between the fitness increase and the appearance and fixation of mutations. In addition, these fixed mutations presented molecular signatures of positive selection through the accumulation of non-synonymous substitutions. Interestingly, viral recombination correlated with fitness recovery in most of studied viral quasispecies. The genetic diversity generated by these evolutionary processes was positively correlated with the viral fitness. We conclude that HIV-1 fitness recovery can be derived from the genetic heterogeneity generated through both mutation and recombination, and under diversifying molecular adaptation. The findings also suggest nonrandom evolutionary pathways for in vitro fitness recovery.

  12. Testing the influence of family structure and outbreeding depression on heterozygosity-fitness correlations in small populations.

    PubMed

    Jourdan-Pineau, Helene; Folly, Joy; Crochet, Pierre-Andre; David, Patrice

    2012-11-01

    Theory predicts that positive heterozygosity-fitness correlations (HFCs) arise as a consequence of inbreeding, which is often assumed to have a strong impact in small, fragmented populations. Yet according to empirical data, HFC in such populations seem highly variable and unpredictable. We here discuss two overlooked phenomena that may contribute to this variation. First, in a small population, each generation may consist of a few families. This generates random correlations between particular alleles and fitness (AFCs, allele-fitness correlations) and results in too liberal tests for HFC. Second, in some contexts, small populations receiving immigrants may be more impacted by outbreeding depression than by inbreeding depression, resulting in negative rather than positive HFC. We investigated these processes through a case study in tadpole cohorts of Pelodytes punctatus living in small ponds. We provide evidence for a strong family structure and significant AFC in this system, as well as an example of negative HFC. By simulations, we show that this negative HFC cannot be a spurious effect of family structure, and therefore reflects outbreeding depression in the studied population. Our example suggests that a detailed examination of AFC and HFC patterns can provide valuable insights into the internal genetic structure and sources of fitness variation in small populations.

  13. A flexible method for estimating the fraction of fitness influencing mutations from large sequencing data sets.

    PubMed

    Moon, Sunjin; Akey, Joshua M

    2016-06-01

    A continuing challenge in the analysis of massively large sequencing data sets is quantifying and interpreting non-neutrally evolving mutations. Here, we describe a flexible and robust approach based on the site frequency spectrum to estimate the fraction of deleterious and adaptive variants from large-scale sequencing data sets. We applied our method to approximately 1 million single nucleotide variants (SNVs) identified in high-coverage exome sequences of 6515 individuals. We estimate that the fraction of deleterious nonsynonymous SNVs is higher than previously reported; quantify the effects of genomic context, codon bias, chromatin accessibility, and number of protein-protein interactions on deleterious protein-coding SNVs; and identify pathways and networks that have likely been influenced by positive selection. Furthermore, we show that the fraction of deleterious nonsynonymous SNVs is significantly higher for Mendelian versus complex disease loci and in exons harboring dominant versus recessive Mendelian mutations. In summary, as genome-scale sequencing data accumulate in progressively larger sample sizes, our method will enable increasingly high-resolution inferences into the characteristics and determinants of non-neutral variation.

  14. The Influences on Teaching Perspectives of Australian Physical Education Teacher Education Students: The First-Year Influences on Teaching Perspectives Exploratory (FIT-PE) Study

    ERIC Educational Resources Information Center

    Hyndman, Brendon P.; Pill, Shane

    2016-01-01

    There has been a paucity of literature investigating the teaching beliefs and intentions of Australian physical education teacher education (PETE) students that enter teacher training. The First-year Influences on Teaching Perspectives Exploratory (FIT-PE) study explores the teaching perspectives of first year PETE students; including teaching…

  15. Influence of cardiorespiratory fitness and physical activity levels on cardiometabolic risk factors during menopause transition: A MONET study.

    PubMed

    Abdulnour, Joseph; Razmjou, Sahar; Doucet, Éric; Boulay, Pierre; Brochu, Martin; Rabasa-Lhoret, Rémi; Lavoie, Jean-Marc; Prud'homme, Denis

    2016-12-01

    To determine the influence of cardiorespiratory fitness (hereafter "fitness") and physical activity levels on cardiometabolic risk factors in premenopausal women going through the menopause transition. An ancillary study including 66 premenopausal women who participated to a 5-year observational, longitudinal study (2004 to 2009 in Ottawa) on the effects of menopause transition on body composition and cardiometabolic risk factors. Women underwent a graded exercise test on treadmill to measure peak oxygen uptake (VO2 peak) at year 1 and 5 and physical activity levels were measured using accelerometers. Cardiometabolic risk factors included: waist circumference, fasting plasma lipids, glucose and insulin levels, HOMA-IR score, c-reactive protein, apolipoprotein B (apoB) and resting systolic and diastolic blood pressure. Change in fitness was not associated with changes in cardiometabolic risk factors. The changes in total physical activity levels on the other hand showed a significant negative association with apoB levels. Three-way linear mixed model repeated measures, showed lower values of waist circumference, fasting triglycerides, insulin levels, HOMA-IR score, apoB and diastolic blood pressure in women with a fitness ≥ 30.0 mlO2 kg(- 1) min(- 1) compared to women with a fitness < 30.0 mlO2 kg(- 1) min(- 1) (P < 0.05). However, only fasting triglycerides was lower in women with physical activity levels ≥ 770.0 Kcal/day (P < 0.05). Between fitness and physical activity levels, fitness was associated with more favorable values of cardiometabolic risk factors in women followed for 5 years during the menopause transition.

  16. Influence of cardiorespiratory fitness and physical activity levels on cardiometabolic risk factors during menopause transition: A MONET study.

    PubMed

    Abdulnour, Joseph; Razmjou, Sahar; Doucet, Éric; Boulay, Pierre; Brochu, Martin; Rabasa-Lhoret, Rémi; Lavoie, Jean-Marc; Prud'homme, Denis

    2016-12-01

    To determine the influence of cardiorespiratory fitness (hereafter "fitness") and physical activity levels on cardiometabolic risk factors in premenopausal women going through the menopause transition. An ancillary study including 66 premenopausal women who participated to a 5-year observational, longitudinal study (2004 to 2009 in Ottawa) on the effects of menopause transition on body composition and cardiometabolic risk factors. Women underwent a graded exercise test on treadmill to measure peak oxygen uptake (VO2 peak) at year 1 and 5 and physical activity levels were measured using accelerometers. Cardiometabolic risk factors included: waist circumference, fasting plasma lipids, glucose and insulin levels, HOMA-IR score, c-reactive protein, apolipoprotein B (apoB) and resting systolic and diastolic blood pressure. Change in fitness was not associated with changes in cardiometabolic risk factors. The changes in total physical activity levels on the other hand showed a significant negative association with apoB levels. Three-way linear mixed model repeated measures, showed lower values of waist circumference, fasting triglycerides, insulin levels, HOMA-IR score, apoB and diastolic blood pressure in women with a fitness ≥ 30.0 mlO2 kg(- 1) min(- 1) compared to women with a fitness < 30.0 mlO2 kg(- 1) min(- 1) (P < 0.05). However, only fasting triglycerides was lower in women with physical activity levels ≥ 770.0 Kcal/day (P < 0.05). Between fitness and physical activity levels, fitness was associated with more favorable values of cardiometabolic risk factors in women followed for 5 years during the menopause transition. PMID:27453812

  17. Geographical Variation in Health-Related Physical Fitness and Body Composition among Chilean 8th Graders: A Nationally Representative Cross-Sectional Study

    PubMed Central

    Garber, Michael D.; Sajuria, Marcelo; Lobelo, Felipe

    2014-01-01

    Purpose In addition to excess adiposity, low cardiorespiratory fitness (CRF) and low musculoskeletal fitness (MSF) are important independent risk factors for future cardio-metabolic disease in adolescents, yet global fitness surveillance in adolescents is poor. The objective of this study was to describe and investigate geographical variation in levels of health-related physical fitness, including CRF, MSF, body mass index (BMI), and waist circumference (WC) in Chilean 8th graders. Methods This cross-sectional study was based on a population-based, representative sample of 19,929 8th graders (median age = 14 years) in the 2011 National Physical Education Survey from Chile. CRF was assessed with the 20-meter shuttle run test, MSF with standing broad jump, and body composition with BMI and WC. Data were classified according to health-related standards. Prevalence of levels of health-related physical fitness was mapped for each of the four variables, and geographical variation was explored at the country level by region and in the Santiago Metropolitan Area by municipality. Results Girls had significantly higher prevalence of unhealthy CRF, MSF, and BMI than boys (p<0.05). Overall, 26% of boys and 55% of girls had unhealthy CRF, 29% of boys and 35% of girls had unhealthy MSF, 29% of boys and 44% of girls had unhealthy BMI, and 31% of adolescents had unhealthy WC. High prevalence of unhealthy fitness levels concentrates in the northern and middle regions of the country and in the North and Southwest sectors for the Santiago Metropolitan Area. Conclusion Prevalence of unhealthy CRF, MSF, and BMI is relatively high among Chilean 8th graders, especially in girls, when compared with global estimates. Identification of geographical regions and municipalities with high prevalence of unhealthy physical fitness presents opportunity for targeted intervention. PMID:25255442

  18. Accuracy of Person-Fit Statistics: A Monte Carlo Study of the Influence of Aberrance Rates

    ERIC Educational Resources Information Center

    St-Onge, Christina; Valois, Pierre; Abdous, Belkacem; Germain, Stephane

    2011-01-01

    Using a Monte Carlo experimental design, this research examined the relationship between answer patterns' aberrance rates and person-fit statistics (PFS) accuracy. It was observed that as the aberrance rate increased, the detection rates of PFS also increased until, in some situations, a peak was reached and then the detection rates of PFS…

  19. Influences of physical fitness on bone mass in women with fibromyalgia.

    PubMed

    Gómez-Cabello, Alba; Vicente-Rodríguez, Germán; Navarro-Vera, Isabel; Martinez-Redondo, Diana; Díez-Sánchez, Carmen; Casajús, José Antonio

    2015-04-01

    The aim of this study was to provide information about the relationship of bone mineral content (BMC) and density (BMD) with some physical-fitness-related variables in a sample of women with fibromyalgia (FM) and age-matched women without FM. Twenty-eight women clinically diagnosed with FM (age 51.1 ± 8.4 yr, M ± SD) and 22 age-matched controls participated in the study. Whole-body BMC and BMD, lean mass, handgrip strength, quadriceps strength, and cardiovascular fitness were measured in all participants. The association between physical-fitness variables and bone-related variables was tested by linear regression controlling for body weight as a possible confounder. There were no differences in BMC or BMD between groups. Women with FM had lower values of handgrip strength, quadriceps strength, and VO2peak than the control group. Handgrip strength and aerobic capacity were associated with BMC and BMD and quadriceps strength was associated with BMD in women with FM; however, only VO2peak was associated with BMC in the group of women without FM. Bone mass of women with FM may be more susceptible to changes in physical fitness than that of the women without fibromyalgia. PMID:25799593

  20. Fitness drivers in the threatened Dianthus guliae Janka (Caryophyllaceae): disentangling effects of growth context, maternal influence and inbreeding depression.

    PubMed

    Gargano, D; Gullo, T; Bernardo, L

    2011-01-01

    We studied inbreeding depression, growth context and maternal influence as constraints to fitness in the self-compatible, protandrous Dianthus guliae Janka, a threatened Italian endemic. We performed hand-pollinations to verify outcomes of self- and cross-fertilisation over two generations, and grew inbred and outbred D. guliae offspring under different conditions - in pots, a common garden and field conditions (with/without nutrient addition). The environment influenced juvenile growth and flowering likelihood/rate, but had little effect on inbreeding depression. Significant interactions among genetic and environmental factors influenced female fertility. Overall, genetic factors strongly affected both early (seed mass, seed germination, early survival) and late (seed/ovule ratio) life-history traits. After the first pollination experiment, we detected higher mortality in the selfed progeny, which is possibly a consequence of inbreeding depression caused by over-expression of early-acting deleterious alleles. The second pollination induced a strong loss of reproductive fitness (seed production, seed mass) in inbred D. guliae offspring, regardless of the pollination treatment (selfing/crossing); hence, a strong (genetic) maternal influence constrained early life-history traits of the second generation. Based on current knowledge, we conclude that self-compatibility does not prevent the detrimental effects of inbreeding in D. guliae populations, and may increase the severe extinction risk if out-crossing rates decrease.

  1. Sperm influences female hibernation success, survival and fitness in the bumble-bee Bombus terrestris.

    PubMed

    Baer, Boris; Schmid-Hempel, Paul

    2005-02-01

    We present evidence that in the absence of the transfer of male gland compounds in the ejaculate as well as of behavioural male traits, such as mate guarding or harming of females, sperm itself affects female life-history traits such as hibernation success, female longevity and female fitness. Using the bumble-bee Bombus terrestris, we artificially inseminated queens (females) with sperm from one or several males and show that sire groups (groups of brother males) vary in their effects on queen hibernation survival, longevity and fitness. In addition, multiply inseminated queens always had a lower performance as compared to singly inseminated queens. Apart from these main effects, sire groups (in situations of multiple insemination) affected queen longevity and fitness not independently of each other, i.e. certain sire group combinations were more harmful to queens than others. So far, the cause(s) of these effects remain(s) elusive. Harmful male traits as detected here are not necessarily expected to evolve in social insects because males depend on females for a successful completion of a colony cycle and thus have strong convergent interests with their mates.

  2. Sperm influences female hibernation success, survival and fitness in the bumble-bee Bombus terrestris

    PubMed Central

    Baer, Boris; Schmid-Hempel, Paul

    2005-01-01

    We present evidence that in the absence of the transfer of male gland compounds in the ejaculate as well as of behavioural male traits, such as mate guarding or harming of females, sperm itself affects female life-history traits such as hibernation success, female longevity and female fitness. Using the bumble-bee Bombus terrestris, we artificially inseminated queens (females) with sperm from one or several males and show that sire groups (groups of brother males) vary in their effects on queen hibernation survival, longevity and fitness. In addition, multiply inseminated queens always had a lower performance as compared to singly inseminated queens. Apart from these main effects, sire groups (in situations of multiple insemination) affected queen longevity and fitness not independently of each other, i.e. certain sire group combinations were more harmful to queens than others. So far, the cause(s) of these effects remain(s) elusive. Harmful male traits as detected here are not necessarily expected to evolve in social insects because males depend on females for a successful completion of a colony cycle and thus have strong convergent interests with their mates. PMID:15705558

  3. Influence of various gypsum materials on precision of fit of CAD/CAM-fabricated zirconia copings.

    PubMed

    Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Rhee, Hyun-Sill; Lee, Il-Hyun; Kim, Ji-Hwan

    2015-01-01

    The clinical applicability of CAD/CAM-fabricated zirconia copings is tested using working models made from four different highstrength Type IV gypsum materials. Each of the four materials was used to fabricate 15 zirconia copings. Precision of fit was measured with a digital electron microscope using the silicone replica technique. The mean and standard deviation of each reference point were analyzed using the one-way analysis of the variance (ANOVA) and Tukey's honest significant difference (HSD) tests (α=0.05). The overall marginal and internal fits of the zirconia copings were as follows: GS (GS: Grey Stone) group: 91.43 μm, LS (LS: Light green Stone) Group: 87.89 μm, RS (RS: Red Stone) Group: 88.75 μm, BS (BS: Beige Stone) Group: 82.78 μm. There were no significant differences between the mean adaptations of the gypsum varieties (p>0.05). This confirmed that the type of gypsum material used does not determine the precision of fit of a prosthesis. PMID:25748454

  4. For Fit's Sake: A Norms-Based Approach to Healthy Behaviors Through Influence of Presumed Media Influence.

    PubMed

    Ho, Shirley S; Lee, Edmund W J; Ng, Kaijie; Leong, Grace S H; Tham, Tiffany H M

    2016-09-01

    Based on the influence of presumed media influence (IPMI) model as the theoretical framework, this study examines how injunctive norms and personal norms mediate the influence of healthy lifestyle media messages on public intentions to engage in two types of healthy lifestyle behaviors-physical activity and healthy diet. Nationally representative data collected from 1,055 adults in Singapore demonstrate partial support for the key hypotheses that make up the extended IPMI model, highlighting the importance of a norms-based approach in health communication. Our results indicate that perceived media influence on others indirectly shaped public intentions to engage in healthy lifestyle behaviors through personal norms and attitude, providing partial theoretical support for the extended IPMI model. Practical implications for health communicators in designing health campaigns media messages to motivate the public to engage in healthy lifestyle are discussed. PMID:26799846

  5. Fitness versus Fatness: Which Influences Health and Mortality Risk the Most?

    PubMed

    Gaesser, Glenn A; Tucker, Wesley J; Jarrett, Catherine L; Angadi, Siddhartha S

    2015-01-01

    Cardiorespiratory fitness (CRF) is a more powerful predictor of mortality than body mass index or adiposity, and improving CRF is more important than losing body fat for reducing risk of cardiovascular disease and all-cause mortality. Data on reduced morbidity and mortality associated with increased CRF are strong and consistent. By contrast, data on intentional weight loss and mortality are uncertain, and weight loss-induced risk factor modification may be largely transient. Because weight loss maintenance is poor and considering the health risks associated with chronic weight instability ( "yo-yo" dieting), we propose an alternative paradigm that focuses on improving CRF rather than reducing body weight. We contend that this is a safer alternative for management of obesity and the associated comorbidities. Exercise adherence may improve if clinicians emphasized to their patients the importance of CRF compared with weight loss in improving health and reducing the risk of chronic diseases. PMID:26166058

  6. Possibility to explain global climate variations by earthquakes influence

    NASA Astrophysics Data System (ADS)

    Molchanov, O.

    2009-12-01

    An additional natural source of the global warming could be heat flux from seismicity. Estimated earthquakes energy release in the near-equatorial Pacific area during a year ≈ 1020 J that is equivalent to the energy released in the detonation about one million atomic bombs of Hiroshima class and produce average power flux due to seismicity ≈ 0.3-1 W/m2 . We have analyzed together the slow climate temperature variations in the near-equatorial Pacific Ocean area (SSTOI indices) and crustal seismic activity in the same region during 1973-2008 time period using correlation analysis and found similarity in seismic and ENSO periodicities (the latter with time lag about 1.5 years). Trends of the processes are also similar showing about 2 times increase in average seismic energy release during the whole period of analysis and conventional 0.10C/(10 years) increase in SSTOI index anomalies. Our main conclusion is on real possibility of climate-seismicity coupling. It is rather probable that at least partially climate ENSO oscillations and temperature anomaly trends are induced by similar variation in seismicity. A mechanism of several years periodicity in the seismic activity is unclear at present. Probably it is initiated in the upper mantle of the Earth (depth 600-700 km) and then penetrates in the crust as so-called deformation (or stress) wave with time delay from 3 to 10 years [1] [1] O.A. Molchanov and S. Uyeda, Upward migration of earthquake hypocenters in Japan,Kurile- Kamchatka and Sunda subduction zones, Physics and Chemistry of the Earth, 34, 423-430, 2009; doi:10.1016/j.pce.2008.09.011.

  7. [Seasonal variation and related influencing factors for tuberculosis].

    PubMed

    Zhang, Z B; Lu, Z Q; Xie, H; Duan, Q H

    2016-08-10

    Tuberculosis is recognized as a chronic respiratory infectious disease and still one of the important public health issues in the world. Douglas reported an unique seasonal pattern (summer peak) of tuberculosis, when compared with most other respiratory diseases in 1996. Since then, there had been many other researchers notified various patterns of seasonality on TB. This paper reviewed all the studies published in the last five years and analyzed the current findings on seasonal variability and influencing factors, in order to explore the risk factors to provide evidence for prevention and control strategies on tuberculosis. PMID:27539356

  8. Primate genome architecture influences structural variation mechanisms and functional consequences.

    PubMed

    Gokcumen, Omer; Tischler, Verena; Tica, Jelena; Zhu, Qihui; Iskow, Rebecca C; Lee, Eunjung; Fritz, Markus Hsi-Yang; Langdon, Amy; Stütz, Adrian M; Pavlidis, Pavlos; Benes, Vladimir; Mills, Ryan E; Park, Peter J; Lee, Charles; Korbel, Jan O

    2013-09-24

    Although nucleotide resolution maps of genomic structural variants (SVs) have provided insights into the origin and impact of phenotypic diversity in humans, comparable maps in nonhuman primates have thus far been lacking. Using massively parallel DNA sequencing, we constructed fine-resolution genomic structural variation maps in five chimpanzees, five orang-utans, and five rhesus macaques. The SV maps, which are comprised of thousands of deletions, duplications, and mobile element insertions, revealed a high activity of retrotransposition in macaques compared with great apes. By comparison, nonallelic homologous recombination is specifically active in the great apes, which is correlated with architectural differences between the genomes of great apes and macaque. Transcriptome analyses across nonhuman primates and humans revealed effects of species-specific whole-gene duplication on gene expression. We identified 13 gene duplications coinciding with the species-specific gain of tissue-specific gene expression in keeping with a role of gene duplication in the promotion of diversification and the acquisition of unique functions. Differences in the present day activity of SV formation mechanisms that our study revealed may contribute to ongoing diversification and adaptation of great ape and Old World monkey lineages.

  9. Primate genome architecture influences structural variation mechanisms and functional consequences

    PubMed Central

    Gokcumen, Omer; Tischler, Verena; Tica, Jelena; Zhu, Qihui; Iskow, Rebecca C.; Lee, Eunjung; Fritz, Markus Hsi-Yang; Langdon, Amy; Stütz, Adrian M.; Pavlidis, Pavlos; Benes, Vladimir; Mills, Ryan E.; Park, Peter J.; Lee, Charles; Korbel, Jan O.

    2013-01-01

    Although nucleotide resolution maps of genomic structural variants (SVs) have provided insights into the origin and impact of phenotypic diversity in humans, comparable maps in nonhuman primates have thus far been lacking. Using massively parallel DNA sequencing, we constructed fine-resolution genomic structural variation maps in five chimpanzees, five orang-utans, and five rhesus macaques. The SV maps, which are comprised of thousands of deletions, duplications, and mobile element insertions, revealed a high activity of retrotransposition in macaques compared with great apes. By comparison, nonallelic homologous recombination is specifically active in the great apes, which is correlated with architectural differences between the genomes of great apes and macaque. Transcriptome analyses across nonhuman primates and humans revealed effects of species-specific whole-gene duplication on gene expression. We identified 13 gene duplications coinciding with the species-specific gain of tissue-specific gene expression in keeping with a role of gene duplication in the promotion of diversification and the acquisition of unique functions. Differences in the present day activity of SV formation mechanisms that our study revealed may contribute to ongoing diversification and adaptation of great ape and Old World monkey lineages. PMID:24014587

  10. Planetary Wave Influence on Wintertime OH Meinel Longitudinal Variation?

    NASA Astrophysics Data System (ADS)

    Winick, J. R.; Picard, R. H.; Wintersteiner, P. P.; Mlynczak, M. G.; Russell, J. M.; Gordley, L.

    2009-05-01

    We report on very unusual conditions in the upper mesosphere during the boreal winters of 2004 and 2006. Unusually bright OH volume emissions, as measured by TIMED/SABER, occurred in the region north of 60N. These emissions also occurred at unusually low altitudes, while at the same time very high temperatures characterized the upper mesosphere. These large perturbations allowed us to see more clearly longitudinal spatial and temporal variations that were present in the emissions. The affected areas varied in size and location on time scales of a few days and had a distinct planetary-wave wave-1 structure. We present data demonstrating the variability in the emissions and temperatures throughout the polar region and the correlations among them, and we contrast their behavior with that in normal years. The underlying cause of the correlations and longitudinal structure appears to be greatly enhanced downwelling in the upper mesosphere, which in turn was produced by unusual dynamical conditions in the lower atmosphere, consisting of stratospheric warmings and perturbations of wave structures within the polar vortex.

  11. Influence of fitness on the integrated neuroendocrine response to aerobic exercise until exhaustion.

    PubMed

    de Diego Acosta, A M; García, J C; Fernández-Pastor, V J; Perán, S; Ruiz, M; Guirado, F

    2001-12-01

    A group of trained and sedentary men performed an incremental graded exercise-test to exhaustion in order to assess the organic response of the two main stress-activated systems: the sympathetic nervous system with its endocrine component (the adrenal medulla), and the hypothalamic-pituitary-adrenal (HPA) axis. Maximal plasma concentrations of ACTH, cortisol and endogenous opioids (beta-endorphins) were obtained at the end of the exercise-test in the trained group. Thus ACTH increased from basal value of 21.25 +/- 2.5 pg/ml to 88.78 +/- 11.8 pg/ml at the end of the exercise (p<0.01); cortisol, from 16.56 microg/dl +/- 4.94 microg/dl to 23.80 +/- 4.57 microg/dl in min 15 of the recovery period (p<0.001); and beta-endorphin from 21.80 +/- 8.33 pmol/ml to 64.36 +/- 9.8 pmol/ml in min 3 of the recovery period (p<0.05). Catecholamine levels were increased from initial values at the end of the effort test in both control and trained groups. Control subjects exhibited a higher responsiveness compared to trained and showed superior intrinsic stimulation of the sympathetic nervous system. These results reveal a different response according to fitness in a physical stress situation.

  12. Gut microbes influence fitness and malaria transmission potential of Asian malaria vector Anopheles stephensi.

    PubMed

    Sharma, Anil; Dhayal, Devender; Singh, O P; Adak, T; Bhatnagar, Raj K

    2013-10-01

    The midgut of parasite transmitting vector, Anopheles stephensi is a physiologically dynamic ecological niche of resident microbes. The gut resident microbes of anisomorphic and physiologically variable male and female A. stephensi mosquitoes were different (Rani et al., 2009). To understand the possible interaction of gut microbes and mosquito host, we examined the contribution of the microbe community on the fitness of the adult mosquitoes and their ability to permit development of the malaria parasite. A. stephensi mosquitoes were fed with antibiotic to sterilize their gut to study longevity, blood meal digestion, egg laying and maturation capacity, and consequently ability to support malaria parasite development. The sterilization of gut imparted reduction in longevity by a median of 5 days in male and 2 days in female mosquitoes. Similarly, the sterilization also diminished the reproductive potential probably due to increased rate of the resorption of follicles in ovaries coupled with abated blood meal digestion in gut-sterilized females. Additionally, gut sterilization also led to increased susceptibility to oocyst development upon feeding on malaria infected blood. The susceptibility to malaria parasite introduced upon gut sterilization of A. stephensi was restored completely upon re-colonization of gut by native microbes. The information provided in the study provides insights into the role of the gut-resident microbial community in various life events of the mosquito that may be used to develop alternate malaria control strategies, such as paratransgenesis.

  13. Influence of fitness on the integrated neuroendocrine response to aerobic exercise until exhaustion.

    PubMed

    de Diego Acosta, A M; García, J C; Fernández-Pastor, V J; Perán, S; Ruiz, M; Guirado, F

    2001-12-01

    A group of trained and sedentary men performed an incremental graded exercise-test to exhaustion in order to assess the organic response of the two main stress-activated systems: the sympathetic nervous system with its endocrine component (the adrenal medulla), and the hypothalamic-pituitary-adrenal (HPA) axis. Maximal plasma concentrations of ACTH, cortisol and endogenous opioids (beta-endorphins) were obtained at the end of the exercise-test in the trained group. Thus ACTH increased from basal value of 21.25 +/- 2.5 pg/ml to 88.78 +/- 11.8 pg/ml at the end of the exercise (p<0.01); cortisol, from 16.56 microg/dl +/- 4.94 microg/dl to 23.80 +/- 4.57 microg/dl in min 15 of the recovery period (p<0.001); and beta-endorphin from 21.80 +/- 8.33 pmol/ml to 64.36 +/- 9.8 pmol/ml in min 3 of the recovery period (p<0.05). Catecholamine levels were increased from initial values at the end of the effort test in both control and trained groups. Control subjects exhibited a higher responsiveness compared to trained and showed superior intrinsic stimulation of the sympathetic nervous system. These results reveal a different response according to fitness in a physical stress situation. PMID:12005034

  14. Aerobic fitness influences the response of maximal oxygen uptake and lactate threshold in acute hypobaric hypoxia.

    PubMed

    Koistinen, P; Takala, T; Martikkala, V; Leppäluoto, J

    1995-02-01

    We studied 12 highly trained athletes, 6 male ice-hockey players and 6 cross-country skiers (2 females, 4 males). All of them participated in a maximal electrically braked bicycle ergometer test in a hypobaric chamber at the simulated altitude of 3000m (520 mmHg) and in normobaric conditions two days apart in random order. The maximal oxygen uptake was 57.4 +/- 7.1 (SD) ml/kg/min in normobaria (VO2maxnorm) and 46.6 +/- 4.9 (SD) ml/kg/min in hypobaric hypoxia (VO2maxhyp). The decrease in maximal oxygen uptake (delta VO2max) at the simulated altitude of 3000m correlated significantly (p < 0.05, r = 0.61) to the maximal oxygen uptake in normobaric conditions (VO2maxnorm). The lactate threshold was 43.5 +/- 6.4 (SD) ml/kg/min in normobaria (VO2LTnorm) and 36.5 +/- 4.2 (SD) ml/kg/min in hypobaric hypoxia (VO2LThyp). The decrement (delta VO2LT) of lactate threshold in hypoxia correlated significantly (p < 0.01, r = 0.68) with the lactate threshold in normobaric conditions (VOLTnorm). Thus we observed the largest reduction of both maximal oxygen uptake and lactate threshold during exercise at hypobaric hypoxia in the most fit athletes. PMID:7751080

  15. Acute exercise and aerobic fitness influence selective attention during visual search.

    PubMed

    Bullock, Tom; Giesbrecht, Barry

    2014-01-01

    Successful goal directed behavior relies on a human attention system that is flexible and able to adapt to different conditions of physiological stress. However, the effects of physical activity on multiple aspects of selective attention and whether these effects are mediated by aerobic capacity, remains unclear. The aim of the present study was to investigate the effects of a prolonged bout of physical activity on visual search performance and perceptual distraction. Two groups of participants completed a hybrid visual search flanker/response competition task in an initial baseline session and then at 17-min intervals over a 2 h 16 min test period. Participants assigned to the exercise group engaged in steady-state aerobic exercise between completing blocks of the visual task, whereas participants assigned to the control group rested in between blocks. The key result was a correlation between individual differences in aerobic capacity and visual search performance, such that those individuals that were more fit performed the search task more quickly. Critically, this relationship only emerged in the exercise group after the physical activity had begun. The relationship was not present in either group at baseline and never emerged in the control group during the test period, suggesting that under these task demands, aerobic capacity may be an important determinant of visual search performance under physical stress. The results enhance current understanding about the relationship between exercise and cognition, and also inform current models of selective attention.

  16. The influence of mitonuclear genetic variation on personality in seed beetles

    PubMed Central

    Løvlie, Hanne; Immonen, Elina; Gustavsson, Emil; Kazancioğlu, Erem; Arnqvist, Göran

    2014-01-01

    There is a growing awareness of the influence of mitochondrial genetic variation on life-history phenotypes, particularly via epistatic interactions with nuclear genes. Owing to their direct effect on traits such as metabolic and growth rates, mitonuclear interactions may also affect variation in behavioural types or personalities (i.e. behavioural variation that is consistent within individuals, but differs among individuals). However, this possibility is largely unexplored. We used mitonuclear introgression lines, where three mitochondrial genomes were introgressed into three nuclear genetic backgrounds, to disentangle genetic effects on behavioural variation in a seed beetle. We found within-individual consistency in a suite of activity-related behaviours, providing evidence for variation in personality. Composite measures of overall activity of individuals in behavioural assays were influenced by both nuclear genetic variation and by the interaction between nuclear and mitochondrial genomes. More importantly, the degree of expression of behavioural and life-history phenotypes was correlated and mitonuclear genetic variation affected expression of these concerted phenotypes. These results show that mitonuclear genetic variation affects both behavioural and life-history traits, and they provide novel insights into the maintenance of genetic variation in behaviour and personality. PMID:25320161

  17. The influence of statistical variations on image quality

    NASA Astrophysics Data System (ADS)

    Hultgren, Bror; Hertel, Dirk; Bullitt, Julian

    2006-01-01

    For more than thirty years imaging scientists have constructed metrics to predict psychovisually perceived image quality. Such metrics are based on a set of objectively measurable basis functions such as Noise Power Spectrum (NPS), Modulation Transfer Function (MTF), and characteristic curves of tone and color reproduction. Although these basis functions constitute a set of primitives that fully describe an imaging system from the standpoint of information theory, we found that in practical imaging systems the basis functions themselves are determined by system-specific primitives, i.e. technology parameters. In the example of a printer, MTF and NPS are largely determined by dot structure. In addition MTF is determined by color registration, and NPS by streaking and banding. Since any given imaging system is only a single representation of a class of more or less identical systems, the family of imaging systems and the single system are not described by a unique set of image primitives. For an image produced by a given imaging system, the set of image primitives describing that particular image will be a singular instantiation of the underlying statistical distribution of that primitive. If we know precisely the set of imaging primitives that describe the given image we should be able to predict its image quality. Since only the distributions are known, we can only predict the distribution in image quality for a given image as produced by the larger class of 'identical systems'. We will demonstrate the combinatorial effect of the underlying statistical variations in the image primitives on the objectively measured image quality of a population of printers as well as on the perceived image quality of a set of test images. We also will discuss the choice of test image sets and impact of scene content on the distribution of perceived image quality.

  18. Influence of Atmospheric CO2 Variation on Strom Track Behavior

    NASA Astrophysics Data System (ADS)

    Martynova, Yuliya; Krupchatnikov, Vladimir

    2015-04-01

    The storm tracks are the regions of strong baroclinicity where surface cyclones occur. The effect of increase with following decrease of anthropogenic load on storm tracks activity in the Northern Hemisphere was studied. The global climate system model of intermediate complexity ('Planet Simulator', Fraedrich K. et al., 2005) was used in this study. Anthropogenic forcing was set according to climatic scenario RCP8.5 continued till 4000 AD with fixed CO2 concentration till 3000 AD and linear decrease of anthropogenic load to preindustrial value at two different rates: for 100 and 1000 years. Modeling data analysis showed meridional shift of storm tracks due to atmospheric CO2 concentration variation. When CO2 concentration increases storm tracks demonstrate poleward shifting. When CO2 concentration decreases to preindustrial value storm tracks demonstrate a tendency to equator-ward shifting. Storm tracks, however, don't recover their original activity and location to the full. This manifests itself particularly for 'fast' CO2 concentration decrease. Heat and moisture fluxes demonstrate the same behavior. In addition, analysis of eddy length scale (Kidston J. Et al., 2011) showed their increase at mid-latitudes and decrease at tropic latitudes due to intensive CO2 concentration increase. This might cause poleward shift of mid-latitude jets. Acknowledgements. This work is partially supported by SB RAS project VIII.80.2.1, RFBR grant 13-05-12034, 13-05-00480, 14-05-00502 and grant of the President of the Russian Federation. Fraedrich K., Jansen H., Kirk E., Luksch U., and Lunkeit F. The Planet Simulator: Towards a user friendly model // Meteorol. Zeitschrift. 2005, 14, 299-304. Kidston J., Vallis G.K., Dean S.M., Renwick J.A. Can the increase in the eddy length scale ander global warming cause the poleward shift of the jet streams? // J. Climate. 2011, V.24. P. 3764-3780.

  19. Competitive fitness during feast and famine: how SOS DNA polymerases influence physiology and evolution in Escherichia coli.

    PubMed

    Corzett, Christopher H; Goodman, Myron F; Finkel, Steven E

    2013-06-01

    Escherichia coli DNA polymerases (Pol) II, IV, and V serve dual roles by facilitating efficient translesion DNA synthesis while simultaneously introducing genetic variation that can promote adaptive evolution. Here we show that these alternative polymerases are induced as cells transition from exponential to long-term stationary-phase growth in the absence of induction of the SOS regulon by external agents that damage DNA. By monitoring the relative fitness of isogenic mutant strains expressing only one alternative polymerase over time, spanning hours to weeks, we establish distinct growth phase-dependent hierarchies of polymerase mutant strain competitiveness. Pol II confers a significant physiological advantage by facilitating efficient replication and creating genetic diversity during periods of rapid growth. Pol IV and Pol V make the largest contributions to evolutionary fitness during long-term stationary phase. Consistent with their roles providing both a physiological and an adaptive advantage during stationary phase, the expression patterns of all three SOS polymerases change during the transition from log phase to long-term stationary phase. Compared to the alternative polymerases, Pol III transcription dominates during mid-exponential phase; however, its abundance decreases to <20% during long-term stationary phase. Pol IV transcription dominates as cells transition out of exponential phase into stationary phase and a burst of Pol V transcription is observed as cells transition from death phase to long-term stationary phase. These changes in alternative DNA polymerase transcription occur in the absence of SOS induction by exogenous agents and indicate that cell populations require appropriate expression of all three alternative DNA polymerases during exponential, stationary, and long-term stationary phases to attain optimal fitness and undergo adaptive evolution. PMID:23589461

  20. How Rainfall Variation Influences Reproductive Patterns of African Savanna Ungulates in an Equatorial Region Where Photoperiod Variation Is Absent.

    PubMed

    Ogutu, Joseph O; Owen-Smith, Norman; Piepho, Hans-Peter; Dublin, Holly T

    2015-01-01

    In high temperate latitudes, ungulates generally give birth within a narrow time window when conditions are optimal for offspring survival in spring or early summer, and use changing photoperiod to time conceptions so as to anticipate these conditions. However, in low tropical latitudes day length variation is minimal, and rainfall variation makes the seasonal cycle less predictable. Nevertheless, several ungulate species retain narrow birth peaks under such conditions, while others show births spread quite widely through the year. We investigated how within-year and between-year variation in rainfall influenced the reproductive timing of four ungulate species showing these contrasting patterns in the Masai Mara region of Kenya. All four species exhibited birth peaks during the putative optimal period in the early wet season. For hartebeest and impala, the birth peak was diffuse and offspring were born throughout the year. In contrast, topi and warthog showed a narrow seasonal concentration of births, with conceptions suppressed once monthly rainfall fell below a threshold level. High rainfall in the previous season and high early rains in the current year enhanced survival into the juvenile stage for all the species except impala. Our findings reveal how rainfall variation affecting grass growth and hence herbivore nutrition can govern the reproductive phenology of ungulates in tropical latitudes where day length variation is minimal. The underlying mechanism seems to be the suppression of conceptions once nutritional gains become insufficient. Through responding proximally to within-year variation in rainfall, tropical savanna ungulates are less likely to be affected adversely by the consequences of global warming for vegetation phenology than northern ungulates showing more rigid photoperiodic control over reproductive timing. PMID:26295154

  1. How Rainfall Variation Influences Reproductive Patterns of African Savanna Ungulates in an Equatorial Region Where Photoperiod Variation Is Absent

    PubMed Central

    Ogutu, Joseph O.; Owen-Smith, Norman; Piepho, Hans-Peter; Dublin, Holly T.

    2015-01-01

    In high temperate latitudes, ungulates generally give birth within a narrow time window when conditions are optimal for offspring survival in spring or early summer, and use changing photoperiod to time conceptions so as to anticipate these conditions. However, in low tropical latitudes day length variation is minimal, and rainfall variation makes the seasonal cycle less predictable. Nevertheless, several ungulate species retain narrow birth peaks under such conditions, while others show births spread quite widely through the year. We investigated how within-year and between-year variation in rainfall influenced the reproductive timing of four ungulate species showing these contrasting patterns in the Masai Mara region of Kenya. All four species exhibited birth peaks during the putative optimal period in the early wet season. For hartebeest and impala, the birth peak was diffuse and offspring were born throughout the year. In contrast, topi and warthog showed a narrow seasonal concentration of births, with conceptions suppressed once monthly rainfall fell below a threshold level. High rainfall in the previous season and high early rains in the current year enhanced survival into the juvenile stage for all the species except impala. Our findings reveal how rainfall variation affecting grass growth and hence herbivore nutrition can govern the reproductive phenology of ungulates in tropical latitudes where day length variation is minimal. The underlying mechanism seems to be the suppression of conceptions once nutritional gains become insufficient. Through responding proximally to within-year variation in rainfall, tropical savanna ungulates are less likely to be affected adversely by the consequences of global warming for vegetation phenology than northern ungulates showing more rigid photoperiodic control over reproductive timing. PMID:26295154

  2. How Rainfall Variation Influences Reproductive Patterns of African Savanna Ungulates in an Equatorial Region Where Photoperiod Variation Is Absent.

    PubMed

    Ogutu, Joseph O; Owen-Smith, Norman; Piepho, Hans-Peter; Dublin, Holly T

    2015-01-01

    In high temperate latitudes, ungulates generally give birth within a narrow time window when conditions are optimal for offspring survival in spring or early summer, and use changing photoperiod to time conceptions so as to anticipate these conditions. However, in low tropical latitudes day length variation is minimal, and rainfall variation makes the seasonal cycle less predictable. Nevertheless, several ungulate species retain narrow birth peaks under such conditions, while others show births spread quite widely through the year. We investigated how within-year and between-year variation in rainfall influenced the reproductive timing of four ungulate species showing these contrasting patterns in the Masai Mara region of Kenya. All four species exhibited birth peaks during the putative optimal period in the early wet season. For hartebeest and impala, the birth peak was diffuse and offspring were born throughout the year. In contrast, topi and warthog showed a narrow seasonal concentration of births, with conceptions suppressed once monthly rainfall fell below a threshold level. High rainfall in the previous season and high early rains in the current year enhanced survival into the juvenile stage for all the species except impala. Our findings reveal how rainfall variation affecting grass growth and hence herbivore nutrition can govern the reproductive phenology of ungulates in tropical latitudes where day length variation is minimal. The underlying mechanism seems to be the suppression of conceptions once nutritional gains become insufficient. Through responding proximally to within-year variation in rainfall, tropical savanna ungulates are less likely to be affected adversely by the consequences of global warming for vegetation phenology than northern ungulates showing more rigid photoperiodic control over reproductive timing.

  3. Influence of thermal anisotropy on best-fit estimates of shock normals

    NASA Technical Reports Server (NTRS)

    Lepping, R. P.

    1971-01-01

    The influence of thermal anisotropy on the estimates of interplanetary shock parameters and the associated normals is discussed. A practical theorem is presented for quantitatively correcting for anisotropic effects by weighting the before and after magnetic fields by the same anisotropy parameter h. The quantity h depends only on the thermal anisotropies before and after the shock and on the angles between the magnetic fields and the shock normal. The theorem can be applied to most slow shocks, but in those cases h usually should be lower, and sometimes markedly lower, than unity. For the extreme values of h, little change results in the shock parameters or in the shock normal.

  4. Influence of physical fitness and activity behavior on retinal vessel diameters in primary schoolchildren.

    PubMed

    Imhof, K; Zahner, L; Schmidt-Trucksäss, A; Faude, O; Hanssen, H

    2016-07-01

    Retinal vessel alterations have been shown to be associated with cardiovascular risk factors and physical inactivity as early as childhood. In this context, the analysis of physical activity in children has solely been based on questionnaire assessments. The study aimed to examine the association of physical fitness performance and self-reported physical activity with retinal vessel diameters in young children. Three hundred ninety-one primary schoolchildren [7.3 years (SD 0.4)] were examined in this cross-sectional study. The primary outcome was endurance performance measured with the 20-m shuttle run. The additional tests consisted of a 20-m sprint, jumping sidewards and balancing backwards. Retinal microcirculation was assessed using a static retinal vessel analyzer. Parents completed questionnaires about physical and sedentary activities. Endurance performance was associated with narrower retinal venular diameters [-0.9 (95%CI: -1.8; -0.1) measuring units (mu)/ unit shuttle run, P = 0.04] and a higher arteriolar to venular ratio [0.003 (-0.001; 0.006)/unit shuttle run, P = 0.06]. The sprint performance was associated with narrower retinal arterioles [4.7 (0.8; 8.6) mu/unit sprint, P = 0.02]. Indoor playing activity correlated with narrower retinal venules [-0.04 (-0.07; -0.01) mu/per unit, P = 0.02]. Our data suggest that objectively measured endurance performance relates with better retinal vessel health in early childhood.

  5. Influence of space use on fitness and the reintroduction success of the Laysan teal

    USGS Publications Warehouse

    Reynolds, M.H.; Hatfield, J.S.; Laniawe, L.P.; Vekasy, M.S.; Klavitter, J.L.; Berkowitz, P.; Crampton, L.H.; Walters, J.R.

    2012-01-01

    Translocation is an important tool for wildlife conservation and biodiversity restoration, but an inefficient one because of the unpredictability of success. Predictors of success such as habitat quality of the release site and number of individuals released have been identified, but the dynamics of successful translocations remain poorly understood. In particular, little is known about the relationship of individual post-release movements to population establishment. In 2004, Laysan teal Anas laysanensis were reintroduced by translocating 20 wild birds from Laysan Island to Midway Atoll. Twenty-two additional wild founders were brought the next year. We monitored the survival, reproductive success and movements of the 42 translocated individuals and their offspring for 4 years. Additionally, we monitored population size from 2004 to 2010. Unlike most translocations, we did not observe elevated post-release mortality despite flight-feather trimming to prevent immediate dispersal off-island: first year survival was > 90% and survival rates until 2009 were 0.65±0.08 for founding adults. Laysan teal flew between the two main islands of Midway Atoll, and offspring had significantly larger maximum movement distances than founders. We monitored 84 nests and observed a significant, negative relationship of home range size to productivity for founding females. Flightless founders did not show fidelity to their release sites, but had strong fidelity to annual home ranges after attaining flight. Although we observed a component Allee effect on mate-finding, this did not translate into a demographic Allee effect, and generally, the high fitness of founders contributed substantially to successful population establishment. Laysan teal abundance increased linearly until 2009, but showed evidence of population regulation afterwards. The population estimate was 473 (95% confidence interval 439–508) in 2010. On the much larger main Hawaiian Islands, we expect greater post

  6. Multiple sprint work : physiological responses, mechanisms of fatigue and the influence of aerobic fitness.

    PubMed

    Glaister, Mark

    2005-01-01

    The activity patterns of many sports (e.g. badminton, basketball, soccer and squash) are intermittent in nature, consisting of repeated bouts of brief (fitness and fatigue during multiple sprint work. However, whilst the theoretical basis for such a relationship is compelling, corroborative research is far from substantive. Despite years of investigation, limitations in analytical techniques combined with

  7. Individual variation in life history characteristics can influence extinction risk (vol 144, pg 61, 2001) Correction

    SciTech Connect

    Jager, Yetta

    2009-01-01

    The white sturgeon (Acipenser transmontanus) shows great individual variation in the age at maturation. This study examines the consequences of model assumptions about individual variation in the age at maturation on predicted population viability. I considered: (1) the effects of variation in age at maturation alone; (2) the effects of heritability; and (3) the influence of a stable and an altered selective regime. Two selective regimes represented conditions before and after the impoundment of a river, blocking access of anadromous white sturgeon populations to the ocean. In contrast to previous simulation studies, I found that increased individual variation in the age at maturity did not necessarily lead to a higher likelihood of persistence. Individual variation increased the simulated likelihood of persistence when the variation was heritable and the selective regime had changed such that the mean age at maturity was no longer optimal.

  8. Influence of muscle fitness test performance on metabolic risk factors among adolescent girls

    PubMed Central

    2010-01-01

    Background The purpose of this study was to examine the association between muscular fitness (MF), assessed by 2 components of Fitnessgram test battery, the Curl-Up and Push-Ups tests and the metabolic risk score among adolescent girls. Methods A total of 229 girls (aged 12-15 years old) comprised the sample of this study. Anthropometric data (height, body mass, waist circumference) were collected. Body mass index (BMI) was also calculated. Muscular strength was assessed taking into account the tests that comprised the FITNESSGRAM test battery, i.e. the curl-up and the push-up. Participants were then categorized in one of 3 categories according the number of tests in which they accomplished the scores that allow them to be classified in health or above health zone. The blood pressure [BP], fasting total cholesterol [TC], low density lipoprotein-cholesterol [LDL-C], high density lipoprotein-cholesterol [HDL-C], triglycerides [TG], glucose, and a metabolic risk score (MRS) were also examined. Physical Activity Index (PAI) was obtained by questionnaire. Results Higher compliance with health-zone criteria (good in the 2 tests), adjusted for age and maturation, were positive and significantly (p ≤ 0.05) associated with height (r = 0.19) and PAI (r = 0.21), while a significant but negative association was found for BMI (r = -0.12); WC (r = -0.19); TC (r = -0.16); TG (r = -0.16); LDL (r = -0.16) and MRS (r = -0.16). Logistic regression showed that who were assigned to MF fittest group were less likely (OR = 0.27; p = 0.003) to be classified overweight/obese and less likely (OR = 0.26; p = 0.03) to be classified as having MRS. This last association was also found for those whom only performed 1 test under the health zone (OR = 0.23; p = 0.02). Conclusions Our data showed that low strength test performance was associated with increased risk for obesity and metabolic risk in adolescent girls even after adjustment for age and maturation. PMID:20573222

  9. Separating Pumping and Other Influences on Groundwater Head Variation

    NASA Astrophysics Data System (ADS)

    Shapoori, V.; Western, A. W.; Peterson, T. J.; Costelloe, J.

    2012-12-01

    The dynamics of unconfined groundwater levels are usually the result of numerous and interacting factors, such as land cover change, climate variability and groundwater pumping. Estimating the impact from pumping is highly significant for resource management but also very challenging. A variety of methods are used to model water-table dynamics influenced by pumping, ranging from spatially explicit, numerical models to stochastic approaches. Transfer function noise (TFN) modelling can be used to model the dynamic behaviour of a wide range of hydrologic variables, including time series of groundwater head. Recently, TFN models have been developed to better link water table dynamics with different types of individual stresses, including pumping (Von Asmuth et al. 2002). Peterson & Western (2011) advanced the transfer function noise model of Von Asmuth et al. (2002) to account for non-linear hydrological processes by inclusion of a parsimonious vertically lumped soil moisture storage(SMS). Shapoori et al. (2011) proposed an improved time series formulation for estimation of the impacts of pumping. That study undertook a synthetic assessment of the ability of a range of time series models to represent the impacts of pumping by applying them to groundwater head time series from a synthetic aquifer. This paper further expands the Shapoori at al. (2011) time series method for quantifying the impact of groundwater pumping within unconfined sedimentary aquifers by applying it to real data and by taking account of a surface water body. The study area is the Clydebank groundwater subregion located in Victoria Australia. Nine salinity control pumping bores are used in some of the worst salinity areas to lower the groundwater table and consequently reduce soil salinity. The method has been applied to 43 observation bores and the results show that the model has good predictive performance with mean and minimum coefficient efficiency values of 0.7 and 0.5 respectively. In addition

  10. The Candida albicans Pho4 Transcription Factor Mediates Susceptibility to Stress and Influences Fitness in a Mouse Commensalism Model

    PubMed Central

    Urrialde, Verónica; Prieto, Daniel; Pla, Jesús; Alonso-Monge, Rebeca

    2016-01-01

    The Pho4 transcription factor is required for growth under low environmental phosphate concentrations in Saccharomyces cerevisiae. A characterization of Candida albicans pho4 mutants revealed that these cells are more susceptible to both osmotic and oxidative stress and that this effect is diminished in the presence of 5% CO2 or anaerobiosis, reflecting the relevance of oxygen metabolism in the Pho4-mediated response. A pho4 mutant was as virulent as wild type strain when assayed in the Galleria mellonella infection model and was even more resistant to murine macrophages in ex vivo killing assays. The lack of Pho4 neither impairs the ability to colonize the murine gut nor alters the localization in the gastrointestinal tract. However, we found that Pho4 influenced the colonization of C. albicans in the mouse gut in competition assays; pho4 mutants were unable to attain high colonization levels when inoculated simultaneously with an isogenic wild type strain. Moreover, pho4 mutants displayed a reduced adherence to the intestinal mucosa in a competitive ex vivo assays with wild type cells. In vitro competitive assays also revealed defects in fitness for this mutant compared to the wild type strain. Thus, Pho4, a transcription factor involved in phosphate metabolism, is required for adaptation to stress and fitness in C. albicans. PMID:27458452

  11. The Candida albicans Pho4 Transcription Factor Mediates Susceptibility to Stress and Influences Fitness in a Mouse Commensalism Model.

    PubMed

    Urrialde, Verónica; Prieto, Daniel; Pla, Jesús; Alonso-Monge, Rebeca

    2016-01-01

    The Pho4 transcription factor is required for growth under low environmental phosphate concentrations in Saccharomyces cerevisiae. A characterization of Candida albicans pho4 mutants revealed that these cells are more susceptible to both osmotic and oxidative stress and that this effect is diminished in the presence of 5% CO2 or anaerobiosis, reflecting the relevance of oxygen metabolism in the Pho4-mediated response. A pho4 mutant was as virulent as wild type strain when assayed in the Galleria mellonella infection model and was even more resistant to murine macrophages in ex vivo killing assays. The lack of Pho4 neither impairs the ability to colonize the murine gut nor alters the localization in the gastrointestinal tract. However, we found that Pho4 influenced the colonization of C. albicans in the mouse gut in competition assays; pho4 mutants were unable to attain high colonization levels when inoculated simultaneously with an isogenic wild type strain. Moreover, pho4 mutants displayed a reduced adherence to the intestinal mucosa in a competitive ex vivo assays with wild type cells. In vitro competitive assays also revealed defects in fitness for this mutant compared to the wild type strain. Thus, Pho4, a transcription factor involved in phosphate metabolism, is required for adaptation to stress and fitness in C. albicans.

  12. The influence of active and passive smoking on the cardiorespiratory fitness of adults

    PubMed Central

    2014-01-01

    Background The aim of this study was to analyze the influence of active and passive smoking on cardiorespiratory responses in asymptomatic adults during a sub-maximal-exertion incremental test. Methods The participants (n = 43) were divided into three different groups: active smokers (n = 14; aged 36.5 ± 8 years), passive smokers (n = 14; aged 34.6 ± 11.9 years) and non-smokers (n = 15; aged 30 ± 8.1 years). They all answered the Test for Nicotine Dependence and underwent anthropometric evaluation, spirometry and ergospirometry according to the Bruce Treadmill Protocol. Results VO2max differed statistically between active and non-smokers groups (p < 0.001) and between non-smokers and passive group (p=0.022). However, there was no difference between the passive and active smokers groups (p=0.053). Negative and significant correlations occurred between VO2max and age (r = - 0.401, p = 0.044), percentage of body fat (r = - 0.429, p = 0.011), and waist circumference (WC) (r = - 0.382, p = 0.025). Conclusion VO2max was significantly higher in non-smokers compared to active smokers and passive smokers. However, the VO2max of passive smokers did not differ from active smokers. PMID:25009739

  13. [Influence of a variation potential on photosynthesis in pumpkin seedlings (Cucurbita pepo L.)].

    PubMed

    Sukhov, V S; Shesterneva, O N; Surova, L M; Rumiantsev, E A; Vodeneev, V A

    2013-01-01

    The influence of a variation potential on photosynthesis in pumpkin seedlings (Cucurbita pepo L.) was investigated in our work. It was shown that the variation potential induced by cotyledon burning propagates into a leaf. It decreases CO2 assimilation and transpiration as well as increases nonphotochemical quenching. Investigation of isolated chloroplasts showed that lowering of the pH in incubation medium from 6.9-7.2 to 6.5 increases nonphotochemical quenching. It was proposed that lowering of the cytoplasmic pH induced by the variation potential takes place in the photosynthetic response development.

  14. Influence of rock-soil spectral variation on the assessment of green biomass

    NASA Technical Reports Server (NTRS)

    Elvidge, C. D.; Lyon, R. J. P.

    1985-01-01

    A comparison of how n-spaced and ratio-based vegetation indices respond to rock and soil spectral variation is made, using a set of ground-based reflectance spectra and airborne Thematic Mapper imagery of the Virginia Range, NV. The influence of variations in rock-soil brightness on ratio-based vegetation indices is also discussed. It is shown that of all the vegetation indices tested, the perperdicular vegetation index is the most appropriate for use in multispectral imagery of arid and semiarid regions where there is a wide variation in substrate characteristics.

  15. The influence of fine-scale habitat features on regional variation in population performance of alpine White-tailed Ptarmigan

    USGS Publications Warehouse

    Fedy, B.; Martin, K.

    2011-01-01

    It is often assumed (explicitly or implicitly) that animals select habitat features to maximize fitness. However, there is often a mismatch between preferred habitats and indices of individual and population measures of performance. We examined the influence of fine-scale habitat selection on the overall population performance of the White-tailed Ptarmigan (Lagopus leucura), an alpine specialist, in two subdivided populations whose habitat patches are configured differently. The central region of Vancouver Island, Canada, has more continuous and larger habitat patches than the southern region. In 2003 and 2004, using paired logistic regression between used (n = 176) and available (n = 324) sites, we identified food availability, distance to standing water, and predator cover as preferred habitat components . We then quantified variation in population performance in the two regions in terms of sex ratio, age structure (n = 182 adults and yearlings), and reproductive success (n = 98 females) on the basis of 8 years of data (1995-1999, 2002-2004). Region strongly influenced females' breeding success, which, unsuccessful hens included, was consistently higher in the central region (n = 77 females) of the island than in the south (n = 21 females, P = 0.01). The central region also had a much higher proportion of successful hens (87%) than did the south (55%, P < 0.001). In light of our findings, we suggest that population performance is influenced by a combination of fine-scale habitat features and coarse-scale habitat configuration. ?? The Cooper Ornithological Society 2011.

  16. Explaining Racial/Ethnic Variation in Partnered Women’s and Men’s Housework: Does One Size Fit All?

    PubMed Central

    Wight, Vanessa R.; Bianchi, Suzanne M.; Hunt, Bijou R.

    2014-01-01

    Using a national sample of 12,424 partnered women and 10,721 partnered men from the 2003–2006 American Time Use Survey, this article examines racial/ethnic variation in women’s and men’s housework time and its covariates. The ratio of women’s to men’s housework hours is greatest for Hispanics and Asians and smallest for Whites and Blacks. White and Hispanic women’s housework hours are associated with household composition and employment suggesting that the time availability perspective is a good predictor for these women, but may have less explanatory power for other race/ ethnic groups of women. Relative resources also have explanatory power for White women’s housework time but are weak predictors for women of Other race/ethnicities. Time availability and relative resource measures show some association with White men’s housework time but are generally poor predictors among other race/ethnic groups of men, suggesting that traditional models of housework allocation do not “fit” all groups equally. PMID:25429170

  17. Individual Variation in Agrammatism: A Single Case Study of the Influence of Interaction

    ERIC Educational Resources Information Center

    Beeke, Suzanne; Wilkinson, Ray; Maxim, Jane

    2007-01-01

    Background: Agrammatic speech can manifest in different ways in the same speaker if task demands change. Individual variation is considered to reflect adaptation, driven by psycholinguistic factors such as underlying deficit. Recently, qualitative investigations have begun to show ways in which conversational interaction can influence the form of…

  18. Genetic composition of social groups influences male aggressive behaviour and fitness in natural genotypes of Drosophila melanogaster

    PubMed Central

    Saltz, Julia B.

    2013-01-01

    Indirect genetic effects (IGEs) describe how an individual's behaviour—which is influenced by his or her genotype—can affect the behaviours of interacting individuals. IGE research has focused on dyads. However, insights from social networks research, and other studies of group behaviour, suggest that dyadic interactions are affected by the behaviour of other individuals in the group. To extend IGE inferences to groups of three or more, IGEs must be considered from a group perspective. Here, I introduce the ‘focal interaction’ approach to study IGEs in groups. I illustrate the utility of this approach by studying aggression among natural genotypes of Drosophila melanogaster. I chose two natural genotypes as ‘focal interactants’: the behavioural interaction between them was the ‘focal interaction’. One male from each focal interactant genotype was present in every group, and I varied the genotype of the third male—the ‘treatment male’. Genetic variation in the treatment male's aggressive behaviour influenced the focal interaction, demonstrating that IGEs in groups are not a straightforward extension of IGEs measured in dyads. Further, the focal interaction influenced male mating success, illustrating the role of IGEs in behavioural evolution. These results represent the first manipulative evidence for IGEs at the group level. PMID:24068359

  19. Influence of Military Training and Standardized Nutrition in Military Unit on Soldiers' Nutritional Status and Physical Fitness.

    PubMed

    Tomczak, Andrzej; Bertrandt, Jerzy; Kłos, Anna; Kłos, Krzysztof

    2016-10-01

    Tomczak, A, Bertrandt, J, Kłos, A, and Kłos, K. Influence of military training and standardized nutrition in military unit on soldiers' nutritional status and physical fitness. J Strength Cond Res 30(10): 2774-2780, 2016-Despite suspension of conscription in Polish Army, trainings of soldiers are still carried out. It is expected that they will be effective and will contribute to obtaining optimum level of psychophysical efficiency that enables fulfillment of military tasks. Total of 60 soldiers took part in the study. During the 9-month military service, soldiers had 200 hours of physical training and basic military training (shooting, drill, anti-chemical training, topography, general tactics, and military equipment operation). The training lasted 8 hours everyday. To assess fitness level, 4 trials were done: long jump, pull-ups, sit-ups, and 1,000 m run. Evaluation of food was based on the analysis of full board menus using the "Tables of composition and nutritional value of food products." Energy value was assessed, and content of basic nutrients was calculated. Assessment of nutritional status was based on anthropometric measurements, such as body height, body mass, and thickness of 4 selected skinfolds. Body height and body mass were the basis for the body mass index calculation. Soldiers serving in the mechanized infantry unit, after completing the training, got better results only in 1,000 m run (from 250.3 to 233.61 seconds). During the research, an average energy value of a daily food ration planned for consumption was 4,504 kcal. This value consisted of 13.2% of energy from protein, 31.9% of energy from fat, and 54.9% from carbohydrates. In the course of military service, percentage of subjects indicating overweight increased from 10.2 to 25.4%.

  20. Influence of taekwondo as security martial arts training on anaerobic threshold, cardiorespiratory fitness, and blood lactate recovery.

    PubMed

    Kim, Dae-Young; Seo, Byoung-Do; Choi, Pan-Am

    2014-04-01

    [Purpose] This study was conducted to determine the influence of Taekwondo as security martial arts training on anaerobic threshold, cardiorespiratory fitness, and blood lactate recovery. [Subjects and Methods] Fourteen healthy university students were recruited and divided into an exercise group and a control group (n = 7 in each group). The subjects who participated in the experiment were subjected to an exercise loading test in which anaerobic threshold, value of ventilation, oxygen uptake, maximal oxygen uptake, heart rate, and maximal values of ventilation / heart rate were measured during the exercise, immediately after maximum exercise loading, and at 1, 3, 5, 10, and 15 min of recovery. [Results] At the anaerobic threshold time point, the exercise group showed a significantly longer time to reach anaerobic threshold. The exercise group showed significantly higher values for the time to reach VO2max, maximal values of ventilation, maximal oxygen uptake and maximal values of ventilation / heart rate. Significant changes were observed in the value of ventilation volumes at the 1- and 5-min recovery time points within the exercise group; oxygen uptake and maximal oxygen uptake were significantly different at the 5- and 10-min time points; heart rate was significantly different at the 1- and 3-min time points; and maximal values of ventilation / heart rate was significantly different at the 5-min time point. The exercise group showed significant decreases in blood lactate levels at the 15- and 30-min recovery time points. [Conclusion] The study results revealed that Taekwondo as a security martial arts training increases the maximal oxygen uptake and anaerobic threshold and accelerates an individual's recovery to the normal state of cardiorespiratory fitness and blood lactate level. These results are expected to contribute to the execution of more effective security services in emergencies in which violence can occur.

  1. The interrelationship between muscle oxygenation, muscle activation, and pulmonary oxygen uptake to incremental ramp exercise: influence of aerobic fitness.

    PubMed

    Boone, Jan; Barstow, Thomas J; Celie, Bert; Prieur, Fabrice; Bourgois, Jan

    2016-01-01

    We investigated whether muscle and ventilatory responses to incremental ramp exercise would be influenced by aerobic fitness status by means of a cross-sectional study with a large subject population. Sixty-four male students (age: 21.2 ± 3.2 years) with a heterogeneous peak oxygen uptake (51.9 ± 6.3 mL·min(-1)·kg(-1), range 39.7-66.2 mL·min(-1)·kg(-1)) performed an incremental ramp cycle test (20-35 W·min(-1)) to exhaustion. Breath-by-breath gas exchange was recorded, and muscle activation and oxygenation were measured with surface electromyography and near-infrared spectroscopy, respectively. The integrated electromyography (iEMG), mean power frequency (MPF), deoxygenated [hemoglobin and myoglobin] (deoxy[Hb+Mb]), and total[Hb+Mb] responses were set out as functions of work rate and fitted with a double linear function. The respiratory compensation point (RCP) was compared and correlated with the breakpoints (BPs) (as percentage of peak oxygen uptake) in muscle activation and oxygenation. The BP in total[Hb+Mb] (83.2% ± 3.0% peak oxygen uptake) preceded (P < 0.001) the BP in iEMG (86.7% ± 4.0% peak oxygen uptake) and MPF (86.3% ± 4.1% peak oxygen uptake), which in turn preceded (P < 0.01) the BP in deoxy[Hb+Mb] (88.2% ± 4.5% peak oxygen uptake) and RCP (87.4% ± 4.5% peak oxygen uptake). Furthermore, the peak oxygen uptake was significantly (P < 0.001) positively correlated to the BPs and RCP, indicating that the BPs in total[Hb+Mb] (r = 0.66; P < 0.001), deoxy[Hb+Mb] (r = 0.76; P < 0.001), iEMG (r = 0.61; P < 0.001), MPF (r = 0.63; P < 0.001), and RCP (r = 0.75; P < 0.001) occurred at a higher percentage of peak oxygen uptake in subjects with a higher peak oxygen uptake. In this study a close relationship between muscle oxygenation, activation, and pulmonary oxygen uptake was found, occurring in a cascade of events. In subjects with a higher aerobic fitness level this cascade occurred at a higher relative intensity.

  2. Daily variations in pathogenic bacterial populations in a monsoon influenced tropical environment.

    PubMed

    Khandeparker, Lidita; Anil, Arga Chandrashekar; Naik, Sneha D; Gaonkar, Chetan C

    2015-07-15

    Changing climatic conditions have influenced the monsoon pattern in recent years. Variations in bacterial population in one such tropical environment were observed everyday over two years and point out intra and inter annual changes driven by the intensity of rainfall. Vibrio spp. were abundant during the monsoon and so were faecal coliforms. Vibrio alginolyticus were negatively influenced by nitrate, whereas, silicate and rainfall positively influenced Vibrio parahaemolyticus numbers. It is also known that pathogenic bacteria are associated with the plankton. Changes in the abundance of plankton, which are governed mainly by environmental changes, could be responsible for variation in pathogenic bacterial abundance during monsoon, other than the land runoff due to precipitation and influx of fresh water.

  3. Epigenetic and genetic influences on DNA methylation variation in maize populations.

    PubMed

    Eichten, Steven R; Briskine, Roman; Song, Jawon; Li, Qing; Swanson-Wagner, Ruth; Hermanson, Peter J; Waters, Amanda J; Starr, Evan; West, Patrick T; Tiffin, Peter; Myers, Chad L; Vaughn, Matthew W; Springer, Nathan M

    2013-08-01

    DNA methylation is a chromatin modification that is frequently associated with epigenetic regulation in plants and mammals. However, genetic changes such as transposon insertions can also lead to changes in DNA methylation. Genome-wide profiles of DNA methylation for 20 maize (Zea mays) inbred lines were used to discover differentially methylated regions (DMRs). The methylation level for each of these DMRs was also assayed in 31 additional maize or teosinte genotypes, resulting in the discovery of 1966 common DMRs and 1754 rare DMRs. Analysis of recombinant inbred lines provides evidence that the majority of DMRs are heritable. A local association scan found that nearly half of the DMRs with common variation are significantly associated with single nucleotide polymorphisms found within or near the DMR. Many of the DMRs that are significantly associated with local genetic variation are found near transposable elements that may contribute to the variation in DNA methylation. Analysis of gene expression in the same samples used for DNA methylation profiling identified over 300 genes with expression patterns that are significantly associated with DNA methylation variation. Collectively, our results suggest that DNA methylation variation is influenced by genetic and epigenetic changes that are often stably inherited and can influence the expression of nearby genes.

  4. Influence of dietary specialization and resource availability on geographical variation in abundance of butterflyfish

    PubMed Central

    Lawton, Rebecca J; Pratchett, Morgan S

    2012-01-01

    Empirical evidence indicates that both niche breadth and resource availability are key drivers of a species’ local abundance patterns. However, most studies have considered the influence of either niche breath or resource availability in isolation, while it is the interactive effects that are likely to influence local abundance. We examined geographic variation in the feeding ecology and distribution of coral-feeding butterflyfish to determine the influence of dietary specialization and dietary resource availability on their local abundance. Dietary composition and abundance of five butterflyfish and coral dietary resource availability were determined at 45 sites across five locations (Lizard Island and Heron Island, Great Barrier Reef; Kimbe Bay, Papua New Guinea; Noumea, New Caledonia; and Moorea, French Polynesia). Multiple regression models using variables representative of total dietary resource availability, availability of specific dietary resources, and interspecific competition were used to determine the best predictors of local abundance across all sites and locations for each species. Factors influencing local abundance varied between butterflyfish with specialized and generalized diets. Dietary resource availability had the strongest influence on the abundance of Chaetodon trifascialis—the most specialized species. Local abundance of C. trifascialis was best predicted by availability of the Acropora corals that it preferentially feeds on. In contrast, abundance of generalist butterflyfish was poorly described by variation in availability of specific resources. Rather, indices of total dietary resource availability best predicted their abundance. Overall, multiple regression models only explained a small proportion of the variation in local abundance for all five species. Despite their relatively specialized diets, dietary resource availability has limited influence on the local abundance of butterflyfish. Only the most specialized species appear to

  5. Lean mass as a total mediator of the influence of muscular fitness on bone health in schoolchildren: a mediation analysis.

    PubMed

    Torres-Costoso, Ana; Gracia-Marco, Luis; Sánchez-López, Mairena; García-Prieto, Jorge Cañete; García-Hermoso, Antonio; Díez-Fernández, Ana; Martínez-Vizcaíno, Vicente

    2015-01-01

    This report aims to analyse the independent association of lean mass and muscle fitness with bone mineral content (BMC) and bone mineral density (BMD), and to examine whether the relationship between muscle fitness and bone health is mediated by lean mass. Body composition (by dual energy X-ray absorptiometry (DXA)), muscle fitness, physical activity, age and height were measured in 132 schoolchildren (62 boys, aged 8-11 years). Analysis of covariance tested differences in bone-related variables by lean mass and muscle fitness, controlling for different sets of confounders. Linear regression models fitted for mediation analyses examined whether the association between muscle fitness and bone mass was mediated by lean mass. Children with good performance in handgrip and standing long jump had better and worse bone health, respectively. These differences disappeared after controlling for lean mass. Children with high lean mass had higher values in all bone-related variables. In addition, the relationship between muscle fitness and bone mass was fully mediated by lean mass. In conclusion, the relationship between upper-limbs muscle fitness and bone health seems to be dependent on lean mass but not on muscle fitness. Schoolchildren with high lean mass have more BMC and BMD in all regions. Lean mass mediates the association between muscle fitness and bone mass.

  6. Intrapersonal variation in consumer susceptibility to normative influence: toward a better understanding of brand choice decisions.

    PubMed

    Orth, Ulrich R; Kahle, Lynn R

    2008-08-01

    The authors examined intrapersonal variation in consumer susceptibility to normative influence as a key mediator of wine brand choice. On the basis of a consumer sample, the authors found that individual values and social identity complexity affect consumer susceptibility to normative influence with downstream effects on (a) which brand benefits consumers desire in wine and (b) choice. Individuals higher on internal values and with more complex social identities were less susceptible to normative influence and placed less emphasis on social brand benefits. Separate examinations of consumption scenarios with and without salient reference groups showed that reference group salience interacts with personal values and social identity complexity in affecting consumer susceptibility to normative influence, which in turn affects which brand benefits consumers desire and consequently choice.

  7. Blushing propensity in social anxiety disorder: influence of serotonin transporter gene variation.

    PubMed

    Domschke, Katharina; Stevens, Stephan; Beck, Beate; Baffa, Anna; Hohoff, Christa; Deckert, Jürgen; Gerlach, Alexander L

    2009-06-01

    Blushing is considered to be one of the prime pathophysiological markers of social anxiety disorder, potentially mediated by serotonergic function. Therefore, in the present study 62 patients with social anxiety disorder and 62 age- and sex-matched healthy controls were investigated for the influence of serotonin transporter (5-HTT) gene variation (5-HTTLPR, rs25531) on blushing propensity as measured by the blushing propensity scale (BPS). The less active 5-HTTLPR genotypes were nominally significantly associated with increased blushing propensity in patients with social anxiety disorder as compared to controls with an equidirectional trend for the less active 5-HTTLPR/rs25531 haplotypes. Even when statistically controlled for influence of depression, this association remained significant. In summary, the present pilot study suggests a potential role of functional serotonin transporter gene variation in blushing propensity warranting replication and encouraging genetic analyses of further intermediate phenotypes of social anxiety disorder. PMID:18629430

  8. Spacebased Observations of Oceanic Influence on the Annual Variation of South American Water Balance

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Xie, Xiaosu; Tang, Wenqing; Zlotnicki, Victor

    2006-01-01

    The mass change of South America (SA) continent measured by the Gravity Recovery and Climate Experiment (GRACE) imposes a constraint on the uncertainties in estimating the annual variation of rainfall measured by Tropical Rain Measuring Mission (TRMM) and ocean moisture influx derived from QuikSCAT data. The approximate balance of the mass change rate with the moisture influx less climatological river discharge, in agreement with the conservation principle, bolsters not only the credibility of the spacebased measurements, but supports the characterization of ocean's influence on the annual variation of continental water balance. The annual variation of rainfall is found to be in phase with the mass change rate in the Amazon and the La Plata basins, and the moisture advection across relevant segments of the Pacific and Atlantic coasts agrees with the annual cycle of rainfall in the two basins and the Andes mountains.

  9. Factors influencing the variations of PM10 aerosol dust in Klang Valley, Malaysia during the summer

    NASA Astrophysics Data System (ADS)

    Juneng, Liew; Latif, Mohd Talib; Tangang, Fredolin

    2011-08-01

    The associations between the variations of PM10 concentration during summer monsoon dry seasons over the Klang Valley, Malaysia and the local meteorological factors, synoptic weather conditions as well as the regional hotspots number were examined based on simple multiple linear regression analysis. The regressive relationships established, suggest that the variation of PM10 in Klang Valley was governed significantly by all of the examined factors. Local meteorological conditions are among those factors which governed the largest day-to-day variations of PM10 concentration in the Klang Valley areas during the dry season. When augmented by synoptic meteorological variables and foreign emission sources, a remarkable increase in the explained variance was apparent. On the other hand, domestic burning sources only had a minimal impact on PM10 fluctuations. Important synoptic weather patterns which influence the air pollution variations were also identified. These synoptic conditions include the strengthening of the summer monsoon southwesterly winds over the equatorial area. In addition, the formation of cyclonic circulation, associated with typhoon formation over the north-west Pacific and the South China Sea as well as over the Bay of Bengal, are found to have had a profound impact on PM10 variations over the Malaysian region through the modulation of regional moisture distributions.

  10. Quantifying heritable variation in fitness-related traits of wild, farmed and hybrid Atlantic salmon families in a wild river environment.

    PubMed

    Reed, T E; Prodöhl, P; Hynes, R; Cross, T; Ferguson, A; McGinnity, P

    2015-08-01

    Farmed fish are typically genetically different from wild conspecifics. Escapees from fish farms may contribute one-way gene flow from farm to wild gene pools, which can depress population productivity, dilute local adaptations and disrupt coadapted gene complexes. Here, we reanalyse data from two experiments (McGinnity et al., 1997, 2003) where performance of Atlantic salmon (Salmo salar) progeny originating from experimental crosses between farm and wild parents (in three different cohorts) were measured in a natural stream under common garden conditions. Previous published analyses focussed on group-level differences but did not account for pedigree structure, as we do here using modern mixed-effect models. Offspring with one or two farm parents exhibited poorer survival in their first and second year of life compared with those with two wild parents and these group-level inferences were robust to excluding outlier families. Variation in performance among farm, hybrid and wild families was generally similar in magnitude. Farm offspring were generally larger at all life stages examined than wild offspring, but the differences were moderate (5-20%) and similar in magnitude in the wild versus hatchery environments. Quantitative genetic analyses conducted using a Bayesian framework revealed moderate heritability in juvenile fork length and mass and positive genetic correlations (>0.85) between these morphological traits. Our study confirms (using more rigorous statistical techniques) previous studies showing that offspring of wild fish invariably have higher fitness and contributes fresh insights into family-level variation in performance of farm, wild and hybrid Atlantic salmon families in the wild. It also adds to a small, but growing, number of studies that estimate key evolutionary parameters in wild salmonid populations. Such information is vital in modelling the impacts of introgression by escaped farm salmon.

  11. The role of genetic and chemical variation of Pinus sylvestris seedlings in influencing slug herbivory.

    PubMed

    O'Reilly-Wapstra, Julianne M; Iason, Glenn R; Thoss, Vera

    2007-05-01

    This study investigated the genetic and chemical basis of resistance of Pinus sylvestris seedlings to herbivory by a generalist mollusc, Arion ater. Using feeding trials with captive animals, we examined selective herbivory by A. ater of young P. sylvestris seedlings of different genotypes and correlated preferences with seedling monoterpene levels. We also investigated the feeding responses of A. ater to artificial diets laced with two monoterpenes, Delta(3)-carene and alpha-pinene. Logistic regression indicated that two factors were the best predictors of whether seedlings in the trial would be consumed. Individual slug variation (replicates) was the most significant factor in the model; however, alpha-pinene concentration (also representing beta-pinene, Delta(3)-carene and total monoterpenes due to multicollinearity) of needles was also a significant factor. While A. ater did not select seedlings on the basis of family, seedlings not eaten were significantly higher in levels of alpha-pinene compared to seedlings that were consumed. We also demonstrated significant genetic variation in alpha-pinene concentration of seedlings between different families of P. sylvestris. Nitrogen and three morphological seedling characteristics (stem length, needle length and stem diameter) also showed significant genetic variation between P. sylvestris families. Artificial diets laced with high (5 mg g(-1) dry matter) quantities of either Delta(3)-carene or alpha-pinene, were eaten significantly less than control diets with no added monoterpenes, supporting the results of the seedling feeding trial. This study demonstrates that A. ater selectively feed on P. sylvestris seedlings and that this selection is based, in part, on the monoterpene concentration of seedlings. These results, coupled with significant genetic variation in alpha-pinene concentration of seedlings and evidence that slug herbivory is detrimental to P. sylvestris fitness, are discussed as possible evidence for A

  12. Fit Effect of Motorcycle Helmet

    NASA Astrophysics Data System (ADS)

    Chang, Li-Tung; Chang, Chih-Han; Chang, Guan-Liang

    Optimized assessment of the adequacy of fit conditions between a motorcycle helmet and head size in relation to prevention of head injury remains unclear and is complicated by wide variations in the size and shape characteristics of helmet and wearer’s heads. A finite element model (LS-DYNA3D) based on realistic geometric features of a motorcycle helmet was established to simulate the standard shock absorption test for evaluating the dynamic response and fit effects of a helmet. The model was used to simulate crown, rear and side sites impacts of the helmet. The peak acceleration and Head Injury Criterion (HIC) were employed to assess the protective performance of the helmet against head injuries. The results show that this helmet model had various dynamic responses at different impact sites due to its geometric shape, but that the impact-absorbing capability did not vary markedly within these sites. The fit conditions between the headform and the helmet dramatically affected the assessment of the impact-absorbing capability of the helmet in the standard shock absorption test. However, for a motorcyclist, the helmet fit would have only minor influence on the protection against head injuries. This observation suggests that a better fitting helmet with stable fixation should provide more protection against head injury.

  13. Provincial variation of carbon emissions from bituminous coal: Influence of inertinite and other factors

    USGS Publications Warehouse

    Quick, J.C.; Brill, T.

    2002-01-01

    We observe a 1.3 kg C/net GJ variation of carbon emissions due to inertinite abundance in some commercially available bituminous coal. An additional 0.9 kg C/net GJ variation of carbon emissions is expected due to the extent of coalification through the bituminous rank stages. Each percentage of sulfur in bituminous coal reduces carbon emissions by about 0.08 kg C/net GJ. Other factors, such as mineral content, liptinite abundance and individual macerals, also influence carbon emissions, but their quantitative effect is less certain. The large range of carbon emissions within the bituminous rank class suggests that rank- specific carbon emission factors are provincial rather than global. Although carbon emission factors that better account for this provincial variation might be calculated, we show that the data used for this calculation may vary according to the methods used to sample and analyze coal. Provincial variation of carbon emissions and the use of different coal sampling and analytical methods complicate the verification of national greenhouse gas inventories. Published by Elsevier Science B.V.

  14. Genetic variation in functional traits influences arthropod community composition in aspen (Populus tremula L.).

    PubMed

    Robinson, Kathryn M; Ingvarsson, Pär K; Jansson, Stefan; Albrectsen, Benedicte R

    2012-01-01

    We conducted a study of natural variation in functional leaf traits and herbivory in 116 clones of European aspen, Populus tremula L., the Swedish Aspen (SwAsp) collection, originating from ten degrees of latitude across Sweden and grown in a common garden. In surveys of phytophagous arthropods over two years, we found the aspen canopy supports nearly 100 morphospecies. We identified significant broad-sense heritability of plant functional traits, basic plant defence chemistry, and arthropod community traits. The majority of arthropods were specialists, those coevolved with P. tremula to tolerate and even utilize leaf defence compounds. Arthropod abundance and richness were more closely related to plant growth rates than general chemical defences and relationships were identified between the arthropod community and stem growth, leaf and petiole morphology, anthocyanins, and condensed tannins. Heritable genetic variation in plant traits in young aspen was found to structure arthropod community; however no single trait drives the preferences of arthropod folivores among young aspen genotypes. The influence of natural variation in plant traits on the arthropod community indicates the importance of maintaining genetic variation in wild trees as keystone species for biodiversity. It further suggests that aspen can be a resource for the study of mechanisms of natural resistance to herbivores.

  15. Stochastic variation in food availability influences weight and age at maturity.

    PubMed

    Tenhumberg, B; Tyre, A J; Roitberg, B

    2000-02-21

    Variation in mean food availability, and in the variance around the mean, affects the growth rate during development. Previous theoretical work on the influence of environmental quality or growth rates on the phenotypic traits age and size at maturation assumed that there is no variation in growth rate or food availability within a generation. We develop a stochastic dynamic programming (SDP) model of the foraging behaviour of aphidophagous syrphids, and use this model to predict when syrphids should pupate (mature) when average food availability changes, or varies stochastically, during development. The optimal strategy takes into account not only the availability of food, but also the timing of its availability. Food availability, when small, influences developmental time, but not weight at pupation. Food availability, when large, influences weight at pupation, but not developmental time. When the food supply is low, the optimal strategy adjusts the size at pupation downwards for stochastic as opposed to deterministic availability of food. The conclusions reinforce the need for life-history studies to consider state dependence and short-term variability in growth rates. PMID:10666359

  16. Drift and selection influence geographic variation at immune loci of prairie-chickens.

    PubMed

    Bollmer, Jennifer L; Ruder, Elizabeth A; Johnson, Jeff A; Eimes, John A; Dunn, Peter O

    2011-11-01

    Previous studies of immunity in wild populations have focused primarily on genes of the major histocompatibility complex (MHC); however, studies of model species have identified additional immune-related genes that also affect fitness. In this study, we sequenced five non-MHC immune genes in six greater prairie-chicken (Tympanuchus cupido) populations that have experienced varying degrees of genetic drift as a consequence of population bottlenecks and fragmentation. We compared patterns of geographic variation at the immune genes with six neutral microsatellite markers to investigate the relative effects of selection and genetic drift. Global F(ST) outlier tests identified positive selection on just one of five immune genes (IAP-1) in one population. In contrast, at other immune genes, standardized G'(ST) values were lower than those at microsatellites for a majority of pairwise population comparisons, consistent with balancing selection or with species-wide positive or purifying selection resulting in similar haplotype frequencies across populations. The effects of genetic drift were also evident as summary statistics (e.g., Tajima's D) did not differ from neutrality for the majority of cases, and immune gene diversity (number of haplotypes per gene) was correlated positively with population size. In summary, we found that both genetic drift and selection shaped variation at the five immune genes, and the strength and type of selection varied among genes. Our results caution that neutral forces, such as drift, can make it difficult to detect current selection on genes.

  17. Variation in human mate choice: simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating.

    PubMed

    Zietsch, Brendan P; Verweij, Karin J H; Heath, Andrew C; Martin, Nicholas G

    2011-05-01

    Human mate choice is central to individuals' lives and to the evolution of the species, but the basis of variation in mate choice is not well understood. Here we looked at a large community-based sample of twins and their partners and parents ([Formula: see text] individuals) to test for genetic and family environmental influences on mate choice, while controlling for and not controlling for the effects of assortative mating. Key traits were analyzed, including height, body mass index, age, education, income, personality, social attitudes, and religiosity. This revealed near-zero genetic influences on male and female mate choice over all traits and no significant genetic influences on mate choice for any specific trait. A significant family environmental influence was found for the age and income of females' mate choices, possibly reflecting parental influence over mating decisions. We also tested for evidence of sexual imprinting, where individuals acquire mate-choice criteria during development by using their opposite-sex parent as the template of a desirable mate; there was no such effect for any trait. The main discernible pattern of mate choice was assortative mating; we found that partner similarity was due to initial choice rather than convergence and also at least in part to phenotypic matching.

  18. Chemical Variations Along the EPR Identify Melt Flow and Influence Segmentation

    NASA Astrophysics Data System (ADS)

    Sachi-Kocher, A.; Mallick, S.; Langmuir, C. E.; Salters, V. J.

    2008-12-01

    . Lastly and perhaps most importantly, the chemical variations within the individual ridge segments are distinct from each other. The coincidence of chemical discontinuities with ridge discontinuities is consistent for all eight ridge segments and indicates that the segmentation is influenced by the mantle composition. It is hypothesized that changes in mantle source composition, like variations in the amount veining present, can potentially result in changes in the melting regime like depth of melting and melt rate that causes enough stresses to locate the ridge discontinuities.

  19. Source Variations Along the EPR Identify Melt flow and Influence Segmentation

    NASA Astrophysics Data System (ADS)

    Salters, V. J.; Mallick, S. J.; Sachi-Kocher, A.

    2009-05-01

    importantly, the chemical variations within the individual ridge segments are distinct from each other. Each individual segment represents two component mixing, but the components change from segment to segment. The coincidence of chemical discontinuities with ridge discontinuities is consistent for all eight ridge segments and indicates that the segmentation is influenced by the mantle composition. It is hypothesized that changes in mantle source composition, like variations in solidus or mineralogy, can potentially result in changes in the melting regime like depth of melting and melt rate that causes enough stresses to locate the ridge discontinuities at places where the discontinuities n the mantkle composition are the largest.

  20. Influence of pre- and post-usage flushing frequencies on bacterial water quality of non-touch water fittings

    PubMed Central

    2013-01-01

    Background Non-touch fittings have been reported to be susceptible for Pseudomonas aeruginosa accumulation. A number of factors may contribute to this, including the frequency of usage, duration of water stagnation, or presence of plastic materials. Programmable non-touch fittings are appearing which allow regular automated post-flushing with cold water to prevent water stagnation. However, the ideal duration of post-flushing is unknown as well as the effect of pre-rinsing with cold water before use. Methods Eight non-touch fittings with brass valve blocks were mounted on a mobile test sink and connected to the same central water pipe source, differing only in presence or absence of water connection pipes, length of connection pipe, frequency of usage, and time intervals for pre- and post-usage water flush. The total bacteria colony-forming unit (cfu) counts were obtained by the spread plate technique. Results Low frequency of water use in combination with a long stagnating water column resulted in high bacterial cfu counts. Post-usage flushing for 2 seconds did not differ from no flushing. Flushing for 10 seconds with cold water after use or 30 seconds flush before use were both the most effective measures to prevent non-touch fittings from biofilm formation over a period of 20 weeks. Conclusion Further improvements in water fitting technology could possibly solve the problem of bacterial water contamination in health care settings. PMID:24000790

  1. The influence of variations in Jupiter's plasma environment on the Europa interaction

    NASA Astrophysics Data System (ADS)

    Westlake, J. H.; Case, A. W.; Jia, X.; Kasper, J. C.; Khurana, K. K.; Kivelson, M.; McNutt, R. L., Jr.; Paty, C. S.; Rymer, A. M.; Saur, J.; Slavin, J. A.; Smith, H. T.; Stevens, M. L.

    2014-12-01

    We present a multidisciplinary study of the influence of variations in Jupiter's corotational plasma environment on the details of the Europa interaction and the production of Europa's sputtered atmosphere. We build upon the measurements of the Voyager and Galileo spacecraft with updated models of the Jovian plasma environment and its interaction with Europa. We specifically discuss how plasma perturbations affect the accuracy with which Europa's induction signature can be extracted from measurements and the resulting fidelity of any quantities obtained related to ocean depth and salinity.

  2. Intention to be Physically Active is Influenced by Physical Activity and Fitness, Sedentary Behaviours, and Life Satisfaction in Adolescents.

    PubMed

    Grao-Cruces, Alberto; Fernández-Martínez, Antonio; Nuviala, Alberto; Pérez-Turpin, José A

    2015-09-01

    The aim of this study was to determine the association of levels of physical activity (PA), physical fitness (PF), sedentary lifestyle and life satisfaction with the intention to be physically active after secondary school graduation, in teenagers of both genders. A total of 1986 Spanish adolescents (12-16 years) participated in this cross-sectional study. PA, sedentary lifestyle, life satisfaction and intention to be physically active were assessed through validated questionnaires, and PF was evaluated objectively with the ALPHA battery tests. In both genders, adolescents who had significantly higher odds ratios (OR) of showing low intention to be physically active had low level of PA, cardiorespiratory fitness and muscular fitness in the lower body, and they were more sedentary in front of the computer. The girls that spent a lot of time watching TV and the boys with low life satisfaction also showed higher OR of having low intention to be physically active. PMID:26898051

  3. Reduced Fitness of Virulent Aphis glycines (Hemiptera: Aphididae) Biotypes May Influence the Longevity of Resistance Genes in Soybean

    PubMed Central

    Varenhorst, Adam J.; McCarville, Michael T.; O’Neal, Matthew E.

    2015-01-01

    Sustainable use of insect resistance in crops require insect resistance management plans that may include a refuge to limit the spread of virulence to this resistance. However, without a loss of fitness associated with virulence, a refuge may not prevent virulence from becoming fixed within a population of parthenogenetically reproducing insects like aphids. Aphid-resistance in soybeans (i.e., Rag genes) prevent outbreaks of soybean aphid (Aphis glycines), yet four biotypes defined by their capacity to survive on aphid-resistant soybeans (e.g., biotype-2 survives on Rag1 soybean) are found in North America. Although fitness costs are reported for biotype-3 on aphid susceptible and Rag1 soybean, it is not clear if virulence to aphid resistance in general is associated with a decrease in fitness on aphid susceptible soybeans. In laboratory assays, we measured fitness costs for biotype 2, 3 and 4 on an aphid-susceptible soybean cultivar. In addition, we also observed negative cross-resistance for biotype-2 on Rag3, and biotype-3 on Rag1 soybean. We utilized a simple deterministic, single-locus, four compartment genetic model to account for the impact of these findings on the frequency of virulence alleles. When a refuge of aphid susceptible was included within this model, fitness costs and negative cross-resistance delayed the increase of virulence alleles when virulence was inherited recessively or additively. If virulence were inherited additively, fitness costs decreased the frequency of virulence. Combined, these results suggest that a refuge may prevent virulent A. glycines biotypes from overcoming Rag genes if this aphid-resistance were used commercially in North America. PMID:26372106

  4. Marine and terrestrial influences on interannual CO{sub 2} variations at Mauna Loa and the South Pole

    SciTech Connect

    Dettinger, M.D.; Ghil, M.

    1997-11-01

    Data are presented and very briefly discussed regarding interannual variations of atmospheric carbon dioxide (CO{sub 2}) concentrations. Interannual variations are isolated from monthly concentrations by using singular-spectrum analysis of CO{sub 2} and atmospheric carbon isotopic ratios at Mauna Loa, Hawaii, United States and at the South Pole. Interannual variations are shared at the two sites, and can be used to differentiate between marine and land-surface responses to different interannual climate variations on global scales. Two time-scales are compared: (1) quasi-quadrennial (QQ) and (2) 3-year. Phase relations indicate that QQ variations are dominated by terrestrial influences, whereas the 3-year variations reflect marine (upwelling) influences in the eastern Pacific. The contrasting CO{sub 2} responses on these two time scales thus provide a useful measure of differences in global climate responses, and especially in terrestrial-ecosystem responses to different tropical forcings. 1 fig.

  5. Behavioral adjustments of African herbivores to predation risk by lions: spatiotemporal variations influence habitat use.

    PubMed

    Valeix, M; Loveridge, A J; Chamaillé-Jammes, S; Davidson, Z; Murindagomo, F; Fritz, H; Macdonald, D W

    2009-01-01

    Predators may influence their prey populations not only through direct lethal effects, but also through indirect behavioral changes. Here, we combined spatiotemporal fine-scale data from GPS radio collars on lions with habitat use information on 11 African herbivores in Hwange National Park (Zimbabwe) to test whether the risk of predation by lions influenced the distribution of herbivores in the landscape. Effects of long-term risk of predation (likelihood of lion presence calculated over four months) and short-term risk of predation (actual presence of lions in the vicinity in the preceding 24 hours) were contrasted. The long-term risk of predation by lions appeared to influence the distributions of all browsers across the landscape, but not of grazers. This result strongly suggests that browsers and grazers, which face different ecological constraints, are influenced at different spatial and temporal scales in the variation of the risk of predation by lions. The results also show that all herbivores tend to use more open habitats preferentially when lions are in their vicinity, probably an effective anti-predator behavior against such an ambush predator. Behaviorally induced effects of lions may therefore contribute significantly to structuring African herbivore communities, and hence possibly their effects on savanna ecosystems.

  6. Proton cellular influx as a probable mechanism of variation potential influence on photosynthesis in pea.

    PubMed

    Sukhov, Vladimir; Sherstneva, Oksana; Surova, Lyubov; Katicheva, Lyubov; Vodeneev, Vladimir

    2014-11-01

    Electrical signals (action potential and variation potential, VP) caused by environmental stimuli are known to induce various physiological responses in plants, including changes in photosynthesis; however, their functional mechanisms remain unclear. In this study, the influence of VP on photosynthesis in pea (Pisum sativum L.) was investigated and the proton participation in this process analysed. VP, induced by local heating, inactivated photosynthesis and activated respiration, with the initiation of the photosynthetic response connected with inactivation of the photosynthetic dark stage; however, direct VP influence on the light stage was also probable. VP generation was accompanied with pH increases in apoplasts (0.17-0.30 pH unit) and decreases in cytoplasm (0.18-0.60 pH unit), which probably reflected H(+) -ATPase inactivation and H(+) influx during this electrical event. Imitation of H(+) influx using the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) induced a photosynthetic response that was similar with a VP-induced response. Experiments on chloroplast suspensions showed that decreased external pH also induced an analogous response and that its magnitude depended on the magnitude of pH change. Thus, the present results showed that proton cellular influx was the probable mechanism of VP's influence on photosynthesis in pea. Potential means of action for this influence are discussed.

  7. The nature of nurture in a wild mammal's fitness.

    PubMed

    McFarlane, S Eryn; Gorrell, Jamieson C; Coltman, David W; Humphries, Murray M; Boutin, Stan; McAdam, Andrew G

    2015-05-01

    Genetic variation in fitness is required for the adaptive evolution of any trait but natural selection is thought to erode genetic variance in fitness. This paradox has motivated the search for mechanisms that might maintain a population's adaptive potential. Mothers make many contributions to the attributes of their developing offspring and these maternal effects can influence responses to natural selection if maternal effects are themselves heritable. Maternal genetic effects (MGEs) on fitness might, therefore, represent an underappreciated source of adaptive potential in wild populations. Here we used two decades of data from a pedigreed wild population of North American red squirrels to show that MGEs on offspring fitness increased the population's evolvability by over two orders of magnitude relative to expectations from direct genetic effects alone. MGEs are predicted to maintain more variation than direct genetic effects in the face of selection, but we also found evidence of maternal effect trade-offs. Mothers that raised high-fitness offspring in one environment raised low-fitness offspring in another environment. Such a fitness trade-off is expected to maintain maternal genetic variation in fitness, which provided additional capacity for adaptive evolution beyond that provided by direct genetic effects on fitness. PMID:25833849

  8. The nature of nurture in a wild mammal's fitness.

    PubMed

    McFarlane, S Eryn; Gorrell, Jamieson C; Coltman, David W; Humphries, Murray M; Boutin, Stan; McAdam, Andrew G

    2015-05-01

    Genetic variation in fitness is required for the adaptive evolution of any trait but natural selection is thought to erode genetic variance in fitness. This paradox has motivated the search for mechanisms that might maintain a population's adaptive potential. Mothers make many contributions to the attributes of their developing offspring and these maternal effects can influence responses to natural selection if maternal effects are themselves heritable. Maternal genetic effects (MGEs) on fitness might, therefore, represent an underappreciated source of adaptive potential in wild populations. Here we used two decades of data from a pedigreed wild population of North American red squirrels to show that MGEs on offspring fitness increased the population's evolvability by over two orders of magnitude relative to expectations from direct genetic effects alone. MGEs are predicted to maintain more variation than direct genetic effects in the face of selection, but we also found evidence of maternal effect trade-offs. Mothers that raised high-fitness offspring in one environment raised low-fitness offspring in another environment. Such a fitness trade-off is expected to maintain maternal genetic variation in fitness, which provided additional capacity for adaptive evolution beyond that provided by direct genetic effects on fitness.

  9. The nature of nurture in a wild mammal's fitness

    PubMed Central

    McFarlane, S. Eryn; Gorrell, Jamieson C.; Coltman, David W.; Humphries, Murray M.; Boutin, Stan; McAdam, Andrew G.

    2015-01-01

    Genetic variation in fitness is required for the adaptive evolution of any trait but natural selection is thought to erode genetic variance in fitness. This paradox has motivated the search for mechanisms that might maintain a population's adaptive potential. Mothers make many contributions to the attributes of their developing offspring and these maternal effects can influence responses to natural selection if maternal effects are themselves heritable. Maternal genetic effects (MGEs) on fitness might, therefore, represent an underappreciated source of adaptive potential in wild populations. Here we used two decades of data from a pedigreed wild population of North American red squirrels to show that MGEs on offspring fitness increased the population's evolvability by over two orders of magnitude relative to expectations from direct genetic effects alone. MGEs are predicted to maintain more variation than direct genetic effects in the face of selection, but we also found evidence of maternal effect trade-offs. Mothers that raised high-fitness offspring in one environment raised low-fitness offspring in another environment. Such a fitness trade-off is expected to maintain maternal genetic variation in fitness, which provided additional capacity for adaptive evolution beyond that provided by direct genetic effects on fitness. PMID:25833849

  10. Adverse influence on reproduction and potential fitness cost in survivors of orthene-treated tarnished plant bug, Lygus lineolaris

    Technology Transfer Automated Retrieval System (TEKTRAN)

    By using dose response to Orthene at 80 mg/L (LC50 of the laboratory susceptible colony), a relative resistant population (71% survival rate) of the tarnished plant bug, Lygus lineolaris, was located near Tillar, Arkansas. This population was used in this study to evaluate potential fitness cost in ...

  11. Heritable influences on amygdala and orbitofrontal cortex contribute to genetic variation in core dimensions of personality

    PubMed Central

    Lewis, G.J.; Panizzon, M.S.; Eyler, L.; Fennema-Notestine, C.; Chen, C.-H.; Neale, M.C.; Jernigan, T.L.; Lyons, M.J.; Dale, A.M.; Kremen, W.S.; Franz, C.E.

    2015-01-01

    While many studies have reported that individual differences in personality traits are genetically influenced, the neurobiological bases mediating these influences have not yet been well characterized. To advance understanding concerning the pathway from genetic variation to personality, here we examined whether measures of heritable variation in neuroanatomical size in candidate regions (amygdala and medial orbitofrontal cortex) were associated with heritable effects on personality. A sample of 486 middle-aged (mean = 55 years) male twins (complete MZ pairs = 120; complete DZ pairs = 84) underwent structural brain scans and also completed measures of two core domains of personality: positive and negative emotionality. After adjusting for estimated intracranial volume, significant phenotypic (rp) and genetic (rg) correlations were observed between left amygdala volume and positive emotionality (rp = .16, p < .01; rg = .23, p < .05, respectively). In addition, after adjusting for mean cortical thickness, genetic and nonshared-environmental correlations (re) between left medial orbitofrontal cortex thickness and negative emotionality were also observed (rg = .34, p < .01; re = −.19, p < .05, respectively). These findings support a model positing that heritable bases of personality are, at least in part, mediated through individual differences in the size of brain structures, although further work is still required to confirm this causal interpretation. PMID:25263286

  12. Heritable influences on amygdala and orbitofrontal cortex contribute to genetic variation in core dimensions of personality.

    PubMed

    Lewis, G J; Panizzon, M S; Eyler, L; Fennema-Notestine, C; Chen, C-H; Neale, M C; Jernigan, T L; Lyons, M J; Dale, A M; Kremen, W S; Franz, C E

    2014-12-01

    While many studies have reported that individual differences in personality traits are genetically influenced, the neurobiological bases mediating these influences have not yet been well characterized. To advance understanding concerning the pathway from genetic variation to personality, here we examined whether measures of heritable variation in neuroanatomical size in candidate regions (amygdala and medial orbitofrontal cortex) were associated with heritable effects on personality. A sample of 486 middle-aged (mean=55 years) male twins (complete MZ pairs=120; complete DZ pairs=84) underwent structural brain scans and also completed measures of two core domains of personality: positive and negative emotionality. After adjusting for estimated intracranial volume, significant phenotypic (r(p)) and genetic (r(g)) correlations were observed between left amygdala volume and positive emotionality (r(p)=.16, p<.01; r(g)=.23, p<.05, respectively). In addition, after adjusting for mean cortical thickness, genetic and nonshared-environmental correlations (r(e)) between left medial orbitofrontal cortex thickness and negative emotionality were also observed (r(g)=.34, p<.01; r(e)=-.19, p<.05, respectively). These findings support a model positing that heritable bases of personality are, at least in part, mediated through individual differences in the size of brain structures, although further work is still required to confirm this causal interpretation.

  13. Influence of SLC6A3 and COMT Variation on Neural Activation During Response Inhibition

    PubMed Central

    Congdon, Eliza; Constable, R. Todd; Lesch, Klaus Peter; Canli, Turhan

    2009-01-01

    There is evidence concerning the neural and genetic correlates of inhibitory control, but there have been limited attempts to combine this information. This study tested the hypothesis that two dopaminergic polymorphisms, SLC6A3 and COMT, influence neural activation during response inhibition. Healthy adults were genotyped for these polymorphisms and performed a measure of response inhibition while undergoing functional magnetic resonance imaging (fMRI). Results support the role of key frontostriatal regions underlying response inhibition. Furthermore, results support a significant influence of SLC6A3 and COMT variants on neural activity during inhibition, with greater activation during inhibition in carriers of the SLC6A3 9-allele or the COMT met-allele as compared to carriers of the SLC6A3 10/10 genotype or the COMT val/val genotype. These results add to a growing literature suggesting that inhibitory control is sensitive to variation in dopamine function, and suggest that this variation may be detectable at the level of individuals’ genotypes. PMID:19482231

  14. Natural Genetic Variation Influences Protein Abundances in C. elegans Developmental Signalling Pathways.

    PubMed

    Singh, Kapil Dev; Roschitzki, Bernd; Snoek, L Basten; Grossmann, Jonas; Zheng, Xue; Elvin, Mark; Kamkina, Polina; Schrimpf, Sabine P; Poulin, Gino B; Kammenga, Jan E; Hengartner, Michael O

    2016-01-01

    Complex traits, including common disease-related traits, are affected by many different genes that function in multiple pathways and networks. The apoptosis, MAPK, Notch, and Wnt signalling pathways play important roles in development and disease progression. At the moment we have a poor understanding of how allelic variation affects gene expression in these pathways at the level of translation. Here we report the effect of natural genetic variation on transcript and protein abundance involved in developmental signalling pathways in Caenorhabditis elegans. We used selected reaction monitoring to analyse proteins from the abovementioned four pathways in a set of recombinant inbred lines (RILs) generated from the wild-type strains N2 (Bristol) and CB4856 (Hawaii) to enable quantitative trait locus (QTL) mapping. About half of the cases from the 44 genes tested showed a statistically significant change in protein abundance between various strains, most of these were however very weak (below 1.3-fold change). We detected a distant QTL on the left arm of chromosome II that affected protein abundance of the phosphatidylserine receptor protein PSR-1, and two separate QTLs that influenced embryonic and ionizing radiation-induced apoptosis on chromosome IV. Our results demonstrate that natural variation in C. elegans is sufficient to cause significant changes in signalling pathways both at the gene expression (transcript and protein abundance) and phenotypic levels. PMID:26985669

  15. Fringe Fitting

    NASA Astrophysics Data System (ADS)

    Cotton, W. D.

    Fringe Fitting Theory; Correlator Model Delay Errors; Fringe Fitting Techniques; Baseline; Baseline with Closure Constraints; Global; Solution Interval; Calibration Sources; Source Structure; Phase Referencing; Multi-band Data; Phase-Cals; Multi- vs. Single-band Delay; Sidebands; Filtering; Establishing a Common Reference Antenna; Smoothing and Interpolating Solutions; Bandwidth Synthesis; Weights; Polarization; Fringe Fitting Practice; Phase Slopes in Time and Frequency; Phase-Cals; Sidebands; Delay and Rate Fits; Signal-to-Noise Ratios; Delay and Rate Windows; Details of Global Fringe Fitting; Multi- and Single-band Delays; Phase-Cal Errors; Calibrator Sources; Solution Interval; Weights; Source Model; Suggested Procedure; Bandwidth Synthesis

  16. Flowering phenology in subalpine meadows: does climate variation influence community co-flowering patterns?

    PubMed

    Forrest, Jessica; Inouye, David W; Thomson, James D

    2010-02-01

    Climate change is expected to alter patterns of species co-occurrence, in both space and time. Species-specific shifts in reproductive phenology may alter the assemblages of plant species in flower at any given time during the growing season. Temporal overlap in the flowering periods (co-flowering) of animal-pollinated species may influence reproductive success if competitive or facilitative interactions between plant species affect pollinator services. We used a 33-year data set on flowering phenology in subalpine meadows in Colorado, USA, to determine whether interannual variation in snowmelt date, which marks the start of the growing season, affected co-flowering patterns. For two of four species considered, we found a significant relationship between snowmelt timing and composition of the assemblage of co-flowering plants. In years of early snowmelt, Lathyrus lanszwertii var. leucanthus (Fabaceae), the species we investigated in most detail, tended to overlap with earlier-flowering species and with fewer species overall. In particular, overlap with the flowering period of Lupinus polyphyllus var. prunophilus, with which Lathyrus leucanthus shares pollinators, was significantly reduced in early-snowmelt years. The observed association between timing of snowmelt and patterns of flowering overlap could not have been predicted simply by examining temporal trends in the dates of peak flowering of the dominant species in the community, as peak flowering dates have largely shifted in parallel with respect to snowmelt date. However, subtle interspecific differences in responsiveness of flowering time, duration, and intensity to interannual climate variation have likely contributed to the observed relationship. Although much of the year-to-year variation in flowering overlap remains unexplained by snowmelt date, our finding of a measurable signal of climate variation suggests that future climate change may lead to altered competitive environments for these wildflower

  17. TSPY1 Copy Number Variation Influences Spermatogenesis and Shows Differences among Y Lineages

    PubMed Central

    Giachini, Claudia; Nuti, Francesca; Turner, Daniel J.; Laface, Ilaria; Xue, Yali; Daguin, Fabrice; Forti, Gianni; Tyler-Smith, Chris; Krausz, Csilla

    2012-01-01

    Context TSPY1 is a tandemly-repeated gene on the human Y chromosome forming an array of approximately 21–35 copies. The testicular expression pattern and the inferred function of the TSPY1 protein suggest possible involvement in spermatogenesis. However, data are scarce on TSPY1 copy number variation in different Y lineages and its role in spermatogenesis. Objectives We sought to define: 1) the extent of TSPY1 copy number variation within and among Y chromosome haplogroups; and 2) the role of TSPY1 dosage in spermatogenic efficiency. Materials and Methods A total of 154 idiopathic infertile men and 130 normozoospermic controls from Central Italy were analyzed. We used a quantitative PCR assay to measure TSPY1 copy number and also defined Y haplogroups in all subjects. Results We provide evidence that TSPY1 copy number shows substantial variation among Y haplogroups and thus that population stratification does represent a potential bias in case-control association studies. We also found: 1) a significant positive correlation between TSPY1 copy number and sperm count (P < 0.001); 2) a significant difference in mean TSPY1 copy number between patients and controls (28.4 ± 8.3 vs. 33.9 ± 10.7; P < 0.001); and 3) a 1.5-fold increased risk of abnormal sperm parameters in men with less than 33 copies (P < 0.001). Conclusions TSPY copy number variation significantly influences spermatogenic efficiency. Low TSPY1 copy number is a new risk factor for male infertility with potential clinical consequences. PMID:19773397

  18. Holocene Paleomagnetic Secular Variation and Paleointensity: Influence of High Latitude Flux Lobes on the Tangent Cylinder

    NASA Astrophysics Data System (ADS)

    Stoner, J. S.; Ziegler, L. B.; Reilly, B. T.; Francus, P.; Abbott, M. B.; Cook, T.; Bradley, R. S.

    2014-12-01

    Longitudinal comparisons of high quality, high resolution and independently dated archeomagnetic and paleomagnetic secular variation (PSV) records from the NE Pacific (Alaska & Hawaii), North America, North Atlantic, and Europe during the Holocene show generally coherent multi-centennial to millennial scale variations of specific PSV parameters. These observations illustrate two primary modes (although there are likely others), which we have so far called the European and North American modes after anomalous flux concentrations (lobes) in the late Holocene and historical time average field. Here we explore how mode variations translate into the tangent cylinder. Comparisons of high resolution paleomagnetic records derived from a series of cores retrieved from two Ellesmere Island lakes (Sawtooth Lake, 79º21 N, 83º56 W and Lower Murray Lake, 81°34 N, 69°54 W) with varve based chronologies allow us to define regional PSV and paleointensity (PI) patterns for the last 5kyr. Although Ellesmere Island PSV and PI are distinct from those observed at mid to high latitudes of North America, we observe consistencies in timing with the primary oscillations that at least partially illustrate how variations in the tangent cylinder compare with those at mid-latitudes. We find that Ellesmere Island PIs are weak and VGPs migrate towards the axis of rotation during times when European PIs are strong (European Mode), whereas high North American PIs (North American Mode) are associated with significant changes in Ellesmere Island VGP longitudes. Relative highs in Ellesmere Island PIs are temporally distinct from the timing of the other two. A repeating progression of PI highs are observed, showing than geomagnetic behavior in the tangent cylinder is distinct from, but influenced by large scale oscillations in flux observed at mid to high latitudes.

  19. Influence of porcelain veneering on the marginal fit of Digident and Lava CAD/CAM zirconia ceramic crowns

    PubMed Central

    Pak, Hyun-Soon; Han, Jung-Suk; Lee, Jai-Bong; Kim, Sung-Hun

    2010-01-01

    PURPOSE Marginal fit is a very important factor considering the restoration's long-term success. However, adding porcelain to copings can cause distortion and lead to an inadequate fit which exposes more luting material to the oral environment and causes secondary caries. The purpose of this study was to compare the marginal fit of 2 different all-ceramic crown systems before and after porcelain veneering. This study was also intended to verify the marginal fit of crowns originated from green machining of partially sintered blocks of zirconia (Lava CAD/CAM system) and that of crowns obtained through machining of fully sintered blocks of zirconia (Digident CAD/CAM system). MATERIALS AND METHODS 20 crowns were made per each system and the marginal fit was evaluated through a light microscope with image processing (Accura 2000) at 50 points that were randomly selected. Each crown was measured twice: the first measurement was done after obtaining a 0.5 mm coping and the second measurement was done after porcelain veneering. The means and standard deviations were calculated and statistical inferences among the 2 groups were made using independent t-test and within the same group through paired t-test. RESULTS The means and standard deviations of the marginal fit were 61.52 ± 2.88 µm for the Digident CAD/CAM zirconia ceramic crowns before porcelain veneering and 83.15 ± 3.51 µm after porcelain veneering. Lava CAD/CAM zirconia ceramic crowns showed means and standard deviations of 62.22 ± 1.78 µm before porcelain veneering and 82.03 ± 1.85 µm after porcelain veneering. Both groups showed significant differences when analyzing the marginal gaps before and after porcelain veneering within each group. However, no significant differences were found when comparing the marginal gaps of each group before porcelain veneering and after porcelain veneering as well. CONCLUSION The 2 all-ceramic crown systems showed marginal gaps that were within a reported clinically

  20. Isotopic variation in five species of stream fishes under the influence of different land uses.

    PubMed

    Carvalho, D R; Castro, D; Callisto, M; Moreira, M Z; Pompeu, P S

    2015-09-01

    The aim of this study was to test if changes in land use alter the isotopic signature of fish species, promoting changes in the trophic position and food resource partitioning between these consumers. Three different systems were investigated: pasture streams (n = 3), streams in sugar cane plantations (n = 3) and reference streams (n = 3). Fish species Aspidoras fuscoguttatus, Astyanax altiparanae, Characidium zebra, Hisonotus piracanjuba and Knodus moenkhausii were selected, and their nitrogen and carbon isotopic compositions were estimated to assess changes in the trophic level and partitioning of food items consumed. The composition of δ(13) C (‰) only differed among the land use categories for A. altiparanae, H. piracanjuba and K. moenkhausii. Resource partitioning was different for all species, with changes in the sources or proportions they consumed in each land use category, but only A. altiparanae introduced new food sources in large quantity in altered land uses. It is important to note, however, that the results from the resource partitioning analysis are limited due to large overlapping of isotopic signatures between the analysed food resources. All fish species exhibited variation in δ(15) N (‰), with the highest values found in streams under sugar cane or pasture influence. Despite the variation in nitrogen isotopic values, only C. zebra and H. piracanjuba displayed changes in trophic level. Therefore, it is believed that the increase in the δ(15) N (‰) value of the individuals collected in streams under the influence of sugar cane or pasture was due to the greater influence of livestock dung and chemical and organic fertilizers. The results also highlight the importance of studying consumer species along with all forms of resources available at each location separately, because the signatures of these resources also vary within different land uses. PMID:26201419

  1. Influence of a health-related physical fitness model on students' physical activity, perceived competence, and enjoyment.

    PubMed

    Fu, You; Gao, Zan; Hannon, James; Shultz, Barry; Newton, Maria; Sibthorp, Jim

    2013-12-01

    This study was designed to explore the effects of a health-related physical fitness physical education model on students' physical activity, perceived competence, and enjoyment. 61 students (25 boys, 36 girls; M age = 12.6 yr., SD = 0.6) were assigned to two groups (health-related physical fitness physical education group, and traditional physical education group), and participated in one 50-min. weekly basketball class for 6 wk. Students' in-class physical activity was assessed using NL-1000 pedometers. The physical subscale of the Perceived Competence Scale for Children was employed to assess perceived competence, and children's enjoyment was measured using the Sport Enjoyment Scale. The findings suggest that students in the intervention group increased their perceived competence, enjoyment, and physical activity over a 6-wk. intervention, while the comparison group simply increased physical activity over time. Children in the intervention group had significantly greater enjoyment.

  2. Variation in habitat soundscape characteristics influences settlement of a reef-building coral

    PubMed Central

    Bohnenstiehl, DelWayne; Peters, Jason W.; Eggleston, David

    2016-01-01

    Coral populations, and the productive reef ecosystems they support, rely on successful recruitment of reef-building species, beginning with settlement of dispersing larvae into habitat favourable to survival. Many substrate cues have been identified as contributors to coral larval habitat selection; however, the potential for ambient acoustic cues to influence coral settlement responses is unknown. Using in situ settlement chambers that excluded other habitat cues, larval settlement of a dominant Caribbean reef-building coral, Orbicella faveolata, was compared in response to three local soundscapes, with differing acoustic and habitat properties. Differences between reef sites in the number of larvae settled in chambers isolating acoustic cues corresponded to differences in sound levels and reef characteristics, with sounds at the loudest reef generating significantly higher settlement during trials compared to the quietest site (a 29.5 % increase). These results suggest that soundscapes could be an important influence on coral settlement patterns and that acoustic cues associated with reef habitat may be related to larval settlement. This study reports an effect of soundscape variation on larval settlement for a key coral species, and adds to the growing evidence that soundscapes affect marine ecosystems by influencing early life history processes of foundational species. PMID:27761342

  3. Spatial variation in fish assemblages across a beaver-influenced successional landscape

    USGS Publications Warehouse

    Schlosser, I.J.; Kallemeyn, L.W.

    2000-01-01

    Beavers are increasingly viewed as 'ecological engineers,' having broad effects on physical, chemical, and biological attributes of north-temperate landscapes. We examine the influence of both local successional processes associated with beaver activity and regional geomorphic boundaries on spatial variation in fish assemblages along the Kabetogama Peninsula in Voyageurs National Park, northern Minnesota, USA. Fish abundance and species richness exhibited considerable variation among drainages along the peninsula. Geological barriers to fish dispersal at outlets of some drainages has reduced fish abundance and species richness. Fish abundance and species richness also varied within drainages among local environments associated with beaver pond succession. Fish abundance was higher in upland ponds than in lowland ponds, collapsed ponds, or streams, whereas species richness was highest in collapsed ponds and streams. Cluster analyses based on fish abundance at sites classified according to successional environment indicated that four species (northern redbelly dace, Phoxinus eos; brook stickleback, Culaea inconstans; finescale dace, P. neogaeus; and fathead minnow, Pimephales promelas), were predominant in all successional environments. Several less abundant species were added in collapsed ponds and streams, with smaller size classes of large lake species (e.g., black crappie, Pomoxis nigromaculatus; smallmouth bass, Micropertus dolomieui; yellow perch, Perca flavescens; and burbot, Lota lota) being a component of these less abundant species. The addition of smaller size classes of large lake species indicates that dispersal of early life-history stages from Kabetogama Lake played a role in determining the species richness and composition of less abundant species in successional environments on the peninsula. Furthermore, collapsed-pond and stream environments closer to Kabetogama Lake had higher species richness than similar successional sites located farther from

  4. Pubertal Onset in Girls is Strongly Influenced by Genetic Variation Affecting FSH Action

    PubMed Central

    Hagen, Casper P.; Sørensen, Kaspar; Aksglaede, Lise; Mouritsen, Annette; Mieritz, Mikkel G.; Tinggaard, Jeanette; Wohlfart-Veje, Christine; Petersen, Jørgen Holm; Main, Katharina M.; Meyts, Ewa Rajpert-De; Almstrup, Kristian; Juul, Anders

    2014-01-01

    Age at pubertal onset varies substantially in healthy girls. Although genetic factors are responsible for more than half of the phenotypic variation, only a small part has been attributed to specific genetic polymorphisms identified so far. Follicle-stimulating hormone (FSH) stimulates ovarian follicle maturation and estradiol synthesis which is responsible for breast development. We assessed the effect of three polymorphisms influencing FSH action on age at breast deveopment in a population-based cohort of 964 healthy girls. Girls homozygous for FSHR -29AA (reduced FSH receptor expression) entered puberty 7.4 (2.5–12.4) months later than carriers of the common variants FSHR -29GG+GA, p = 0.003. To our knowledge, this is the strongest genetic effect on age at pubertal onset in girls published to date. PMID:25231187

  5. Seasonal variation and factors influencing perchlorate in water, snow, soil and corns in Northeastern China.

    PubMed

    Ye, Long; You, Hong; Yao, Jie; Kang, Xi; Tang, Lu

    2013-03-01

    Seasonal variation and influencing factors of perchlorate in snow, surface soil, rain, surface water, groundwater and corn were studied. Seven hundreds and seventy samples were collected in different periods in Harbin and its vicinity, China. Perchlorate concentrations were analyzed by ion chromatography-electrospray mass spectrometry. Results indicate that fireworks and firecrackers display from the Spring Festival to the Lantern Festival (February 2, 2011-February 17, 2011) can result in the occurrence of perchlorate in surface soil and snow. Perchlorate distribution is affected by wind direction in winter. Melting snow which contained perchlorate can dissolve perchlorate in surface soil, and then perchlorate can percolate into groundwater so that perchlorate concentrations in groundwater increased in spring. Perchlorate concentrations in groundwater and surface water decrease after rainy season in summer. Groundwater samples collected in the floodplain areas of the Songhua River and the Ashi River contained higher perchlorate concentrations than that far away with the rivers. The corns have the ability to accumulate perchlorate.

  6. Defining the Influence of Germline Variation on Metastasis Using Systems Genetics Approaches.

    PubMed

    Lee, M; Crawford, N P S

    2016-01-01

    Cancer is estimated to be responsible for 8 million deaths worldwide and over half a million deaths every year in the United States. The majority of cancer-related deaths in solid tumors is directly associated with the effects of metastasis. While the influence of germline factors on cancer risk and development has long been recognized, the contribution of hereditary variation to tumor progression and metastasis has only gained acceptance more recently. A variety of approaches have been used to define how hereditary variation influences tumor progression and metastasis. One approach that garnered much early attention was epidemiological studies of cohorts of cancer patients, which demonstrated that specific loci within the human genome are associated with a differential propensity for aggressive tumor development. However, a powerful, and somewhat underutilized approach has been the use of systems genetics approaches in transgenic mouse models of human cancer. Such approaches are typically multifaceted, and involve integration of multiple lines of evidence derived, for example, from genetic and transcriptomic screens of genetically diverse mouse models of cancer, coupled with bioinformatics analysis of human cancer datasets, and functional analysis of candidate genes. These methodologies have allowed for the identification of multiple hereditary metastasis susceptibility genes, with wide-ranging cellular functions including regulation of gene transcription, cell proliferation, and cell-cell adhesion. In this chapter, we review how each of these approaches have facilitated the identification of these hereditary metastasis modifiers, the molecular functions of these metastasis-associated genes, and the implications of these findings upon patient survival. PMID:27613130

  7. Axillary dissection in primary breast cancer: variations of the surgical technique and influence on morbidity.

    PubMed

    Wojcinski, Sebastian; Nuengsri, Sirin; Hillemanns, Peter; Schmidt, Werner; Deryal, Mustafa; Ertan, Kubilay; Degenhardt, Friedrich

    2012-01-01

    Lymphedema of the arm is the most common and impairing complication after breast cancer surgery with axillary lymph node dissection (ALND). Our prospective study evaluated the effect of two different surgical techniques for ALND on postoperative morbidity. Patients were scheduled to undergo ALND. Patients in group 1 (n = 17) underwent the most common and standard technique of ALND, which uses sharp dissection of the tissue and subsequent electro-coagulation of bleedings. Patients in group 2 (n = 17) underwent a modified standard technique of ALND with clamping and ligatures of all resection margins. Postoperative wound secretion was quantified and patients were followed up for 6 months to assess long-term morbidity. The variations in surgical technique had no significant influence on the outcome variables. However, patients in group 2 showed a tendency to less wound secretion (713 versus 802 mL; P = nonsignificant), a decreased rate of immediate postoperative seromas (11.8 versus 23.5%; P = nonsignificant) and less lymphedema after 3 months (29.4 versus 41.2%; P = nonsignificant). Moreover, the number of resected lymph nodes correlated with the total amount of drained fluid (P = 0.006), the duration of the drain (P = 0.015), and the risk for the development of lymphedema after 3 months (P = 0.016). The described variations in surgical technique had no influence on the outcomes of the patients. The number of resected axillary lymph nodes remains the most important risk factor for treatment-related morbidity. Therefore, a well-balanced choice of the extent of the axillary dissection should be the surgeon's main concern. PMID:22570566

  8. Influences of vowel and tone variation on emergent word knowledge: a cross-linguistic investigation.

    PubMed

    Singh, Leher; Hui, Tam Jun; Chan, Calista; Golinkoff, Roberta Michnick

    2014-01-01

    To learn words, infants must be sensitive to native phonological contrast. While lexical tone predominates as a source of phonemic contrast in human languages, there has been little investigation of the influences of lexical tone on word learning. The present study investigates infants' sensitivity to tone mispronunciations in two groups of infants. For one group (Chinese learners), tone is phonemic in their native language, and for the second group (English learners), tone is non-phonemic and constituted suprasegmental variation. In Experiment 1, English learners were trained on novel word-object pairings and tested on their recognition of correct pronunciations, tone and vowel mispronunciations of these words at 18 and 24 months. In Experiment 2a, bilingual English-Chinese learners were tested on a similar task translated into Chinese at the same age intervals. Results demonstrate that non-tonal learners treated tonal and vowel substitutions alike as mispronunciations at 18 months but only treated vowel substitutions as mispronunciations at 24 months. Tonal learners treated both tonal and vowel substitutions as mispronunciations at both ages. In Experiment 2b, bilingual non-tone language learners were tested on the same set of tasks replicating a similar set of results as monolingual non-tone language learners (Experiment 1). Findings point to an early predisposition to treat tone as a defining characteristic of words regardless of its lexical relevance at 18 months. Between 18 and 24 months, learners appear to ascribe lexical relevance to tone in a language-specific manner. The current study identifies the influences of tone variation on memories for newly learned words and the time period during which lexical tone - a highly frequent constituent of human languages - actually becomes lexical for early learners. Findings are contextualized with prevailing models of the developing lexicon. PMID:24118787

  9. Axillary dissection in primary breast cancer: variations of the surgical technique and influence on morbidity

    PubMed Central

    Wojcinski, Sebastian; Nuengsri, Sirin; Hillemanns, Peter; Schmidt, Werner; Deryal, Mustafa; Ertan, Kubilay; Degenhardt, Friedrich

    2012-01-01

    Lymphedema of the arm is the most common and impairing complication after breast cancer surgery with axillary lymph node dissection (ALND). Our prospective study evaluated the effect of two different surgical techniques for ALND on postoperative morbidity. Patients were scheduled to undergo ALND. Patients in group 1 (n = 17) underwent the most common and standard technique of ALND, which uses sharp dissection of the tissue and subsequent electro-coagulation of bleedings. Patients in group 2 (n = 17) underwent a modified standard technique of ALND with clamping and ligatures of all resection margins. Postoperative wound secretion was quantified and patients were followed up for 6 months to assess long-term morbidity. The variations in surgical technique had no significant influence on the outcome variables. However, patients in group 2 showed a tendency to less wound secretion (713 versus 802 mL; P = nonsignificant), a decreased rate of immediate postoperative seromas (11.8 versus 23.5%; P = nonsignificant) and less lymphedema after 3 months (29.4 versus 41.2%; P = nonsignificant). Moreover, the number of resected lymph nodes correlated with the total amount of drained fluid (P = 0.006), the duration of the drain (P = 0.015), and the risk for the development of lymphedema after 3 months (P = 0.016). The described variations in surgical technique had no influence on the outcomes of the patients. The number of resected axillary lymph nodes remains the most important risk factor for treatment-related morbidity. Therefore, a well-balanced choice of the extent of the axillary dissection should be the surgeon’s main concern. PMID:22570566

  10. Axillary dissection in primary breast cancer: variations of the surgical technique and influence on morbidity.

    PubMed

    Wojcinski, Sebastian; Nuengsri, Sirin; Hillemanns, Peter; Schmidt, Werner; Deryal, Mustafa; Ertan, Kubilay; Degenhardt, Friedrich

    2012-01-01

    Lymphedema of the arm is the most common and impairing complication after breast cancer surgery with axillary lymph node dissection (ALND). Our prospective study evaluated the effect of two different surgical techniques for ALND on postoperative morbidity. Patients were scheduled to undergo ALND. Patients in group 1 (n = 17) underwent the most common and standard technique of ALND, which uses sharp dissection of the tissue and subsequent electro-coagulation of bleedings. Patients in group 2 (n = 17) underwent a modified standard technique of ALND with clamping and ligatures of all resection margins. Postoperative wound secretion was quantified and patients were followed up for 6 months to assess long-term morbidity. The variations in surgical technique had no significant influence on the outcome variables. However, patients in group 2 showed a tendency to less wound secretion (713 versus 802 mL; P = nonsignificant), a decreased rate of immediate postoperative seromas (11.8 versus 23.5%; P = nonsignificant) and less lymphedema after 3 months (29.4 versus 41.2%; P = nonsignificant). Moreover, the number of resected lymph nodes correlated with the total amount of drained fluid (P = 0.006), the duration of the drain (P = 0.015), and the risk for the development of lymphedema after 3 months (P = 0.016). The described variations in surgical technique had no influence on the outcomes of the patients. The number of resected axillary lymph nodes remains the most important risk factor for treatment-related morbidity. Therefore, a well-balanced choice of the extent of the axillary dissection should be the surgeon's main concern.

  11. The influence of geographic variations on the muscular activity in selected sports movements.

    PubMed

    Clarys, J P; Alewaeters, K; Zinzen, E

    2001-12-01

    Surface EMG (SEMG) has been used frequently to study motion techniques or skills, body positions, material or equipment used, training-methodology and learning processes in sports and ergonomics. Little if any information is available on the effect of the geographical environment on the neuromuscular control of an athlete or workman during his/her performance or effort. Motions were chosen in Alpine skiing and cycling. Thirty-one certified ski instructors and twelve professional road cyclists participated in the study of geographical variance and its impact on muscle activity. SEMG was measured from the agonists and antagonists of the upper- and lower limb. Skiers were measured on downhill slopes ranging from 19 to 51% while the cyclists performed with different saddle positions on 2, 7 and 12% slope inclinations, respectively. Verification of the variation of muscular intensity (IEMG) over the slope inclination during a simulated giant slalom indicated that the muscular activity increased with increasing slope angle and decreased with decreasing slope angle, while heart rate measured with short-range radio telemetry increased at a constant rate between start and finish independent of the geographical variations. In a direct descent on different slopes % levels the integrated EMG is well related to the inclination (r=0.82) confirming the findings of the giant slalom. In cycling we found that, regardless of the pelvis position, the muscular intensity of lower limb muscles increased with increasing slope inclination, while the muscular intensity of the arms decreased with the same increasing slope inclination. In addition the decreased intensity of the arm muscles remained significantly higher with the pelvis (saddle) fully forward. The geography of the terrain did influence the neuromuscular work and therewith probably the performance also. The influence however, varies with specific circumstances and is coupled with items of variability of the equipment used and

  12. The environmental magnetic record of palaeoenvironmental variations during the past 3100 years: A possible solar influence?

    NASA Astrophysics Data System (ADS)

    Sandeep, K.; Shankar, R.; Warrier, Anish K.; Weijian, Z.; Xuefeng, Lu

    2015-07-01

    Sediments from Pookot Lake (PK) in southern India have provided a record of local environmental changes and catchment processes during the past 3100 cal. years B.P. Variations in the rock magnetic parameters (χlf, χfd, χARM and IRM's at different field strengths) of sediments from two AMS 14C-dated cores reflect climate-induced changes in the catchment of Pookot Lake. Assuming that rainfall is most likely the dominant driving mechanism behind the rock magnetic variations of PK sediments, the environmental history of the site has been reconstructed. Rock magnetic parameters exhibit significant variations during the past 3100 years. The palaeoenvironmental history of the Pookot Lake region may be divided into three phases. During the first phase (~ 3100 to 2500 cal. years B.P.), catchment erosion and detrital influx were high, indicating a strong monsoon. The second phase, which lasted from 2500 to 1000 cal. years B.P., was characterised by low and steady rainfall, resulting in a low and uniform catchment erosion and detrital influx. Phase 2 was interspersed with brief intervals of strong monsoon and characterised by frequent drying up of the lake. During Phase 3 (~ 1000 cal. years B.P. to the present), catchment erosion was high, indicating a shift to strong monsoonal conditions. It appears that monsoonal rainfall in the region is influenced by solar activity, with periods of high total solar irradiance being characterised by high rainfall and vice versa; it was relatively low during the Little Ice Age and high during the Medieval Warm Period. The magnetic susceptibility (χlf) data exhibit a number of periodicities which might have a solar origin. The χlf record exhibits similarities with other continental and marine palaeoclimatic records from the region, indicating that regional trends in the monsoon during the Late Holocene are broadly similar.

  13. Genetic variation in dopamine-related gene expression influences motor skill learning in mice.

    PubMed

    Qian, Y; Chen, M; Forssberg, H; Diaz Heijtz, R

    2013-08-01

    Several neurodevelopmental disorders with a strong genetic basis, including attention-deficit/hyperactivity disorder, autism spectrum disorders and developmental coordination disorder, involve deficits in fine motor skills. This phenotype may depend on heritable variation in components of the dopamine (DA) system, which is known to play a critical role in motor skill learning. In this study, we took advantage of two inbred strains of mice (BALB/c and C57BL/6) that differ markedly in the number of midbrain DA neurons in order to investigate the influence of such naturally occurring genetic variation on the acquisition and performance of fine motor skills. Gene expression analysis of midbrain, frontal cortex and striatum showed significant differences in the expression of presynaptic and postsynaptic dopaminergic (DAergic) markers (e.g. tyrosine hydroxylase, DA transporter, DA D4 receptor, DA D5 receptor and DARPP-32) between these two strains. BALB/c mice had lower learning rate and performance scores in a complex skilled reaching task when compared with C57BL/6 mice. A negative correlation was found between the motor learning rate and level of DARPP-32 mRNA expression in the frontal cortex contralateral to the trained forelimb. The rate of motor learning was also negatively correlated with the levels of DARPP-32 and DA D1 receptor mRNAs in the striatum. Our results suggest that genetically driven variation in frontostriatal DAergic neurotransmission is a major contributor to individual differences in motor skill learning. Moreover, these findings implicate the D1R/cAMP/DARPP-32 signaling pathway in those neurodevelopmental disorders that are associated with fine motor skill deficits.

  14. Genetic Variation of SCNN1A Influences Lung Diffusing Capacity in Cystic Fibrosis

    PubMed Central

    Baker, Sarah E.; Wong, Eric C.; Wheatley, Courtney M.; Foxx-Lupo, William T.; Martinez, Marina G.; Morgan, Mary A.; Sprissler, Ryan; Morgan, Wayne J.; Snyder, Eric M.

    2012-01-01

    Introduction Epithelial Na+ Channels (ENaC) play a crucial role in ion and fluid regulation in the lung. In cystic fibrosis (CF) Na+ hyperabsorption results from ENaC over activity, leading to airway dehydration. Previous work has demonstrated functional genetic variation of SCNN1A (the gene encoding the ENaC α-subunit), manifesting as an alanine (A) to threonine (T) substitution at amino acid 663, with the αT663 variant resulting in a more active channel. Methods We assessed the influence of genetic variation of SCNN1A on the diffusing capacity of the lungs for carbon monoxide (DLCO) and nitric oxide (DLNO), together with alveolar capillary membrane conductance (DM), pulmonary capillary blood volume (VC), and alveolar volume (VA) at rest and during peak exercise in 18 patients with CF [10 homozygous for αA663 (AA group) and 8 with at least one T663 allele (AT/TT group)]. Due to the more active channel we hypothesized that the AT/TT group would show a greater increase in DLCO, DLNO, and DM with exercise due to exercise-mediated ENaC inhibition and subsequent attenuation of Na+ hyperabsorption. Results The AT/TT group had significantly lower pulmonary function, weight and BMI than the AA group. Both groups had similar peak workloads, relative peak oxygen consumptions, and cardiopulmonary responses to exercise. The AT/TT group demonstrated a greater increase in DLNO, DLNO/VA, and DM in response to exercise (% increases: DLNO= 18±11vs.41±38; DLNO/VA= 14±21vs.40±37; DM= 15±11vs.41±38, AAvs.AT/TT, respectively). There were no differences between groups in absolute diffusing capacity measures at peak exercise. Conclusion These results suggest that genetic variation of the alpha-subunit of ENaC differentially affects the diffusing capacity response to exercise in patients with CF. PMID:22776878

  15. The influence of clan structure on the genetic variation in a single Ghanaian village.

    PubMed

    Sanchez-Faddeev, Hernando; Pijpe, Jeroen; van der Hulle, Tom; Meij, Hans J; van der Gaag, Kristiaan J; Slagboom, P Eline; Westendorp, Rudi G J; de Knijff, Peter

    2013-10-01

    Socioeconomic and cultural factors are thought to have an important role in influencing human population genetic structure. To explain such population structure differences, most studies analyse genetic differences among widely dispersed human populations. In contrast, we have studied the genetic structure of an ethnic group occupying a single village in north-eastern Ghana. We found a markedly skewed male population substructure because of an almost complete lack of male gene flow among Bimoba clans in this village. We also observed a deep male substructure within one of the clans in this village. Among all males, we observed only three Y-single-nucleotide polymorphism (SNP) haplogroups: E1b1a*-M2, E1b1a7a*-U174 and E1b1a8a*-U209, P277, P278. In contrast to the marked Y-chromosomal substructure, mitochondrial DNA HVS-1 sequence variation and autosomal short-tandem repeats variation patterns indicate high genetic diversities and a virtually random female-mediated gene flow among clans. On the extreme micro-geographical scale of this single Bimoba village, correspondence between the Y-chromosome lineages and clan membership could be due to the combined effects of the strict patrilocal and patrilineal structure. If translated to larger geographic scales, our results would imply that the extent of variation in uniparentally inherited genetic markers, which are typically associated with historical migration on a continental scale, could equally likely be the result of many small and different cumulative effects of social factors such as clan membership that act at a local scale. Such local scale effects should therefore be considered in genetic studies, especially those that use uniparental markers, before making inferences about human history at large.

  16. Evidence that variation in the peripheral benzodiazepine receptor (PBR) gene influences susceptibility to panic disorder.

    PubMed

    Nakamura, Kazuhiko; Yamada, Kazuo; Iwayama, Yoshimi; Toyota, Tomoko; Furukawa, Aizou; Takimoto, Takahiro; Terayama, Hayato; Iwahashi, Kazuhiko; Takei, Nori; Minabe, Yoshio; Sekine, Yoshimoto; Suzuki, Katsuaki; Iwata, Yasuhide; Pillai, Anitha; Nakamoto, Yurie; Ikeda, Kazutaka; Yoshii, Mitsunobu; Fukunishi, Isao; Yoshikawa, Takeo; Mori, Norio

    2006-04-01

    Panic disorder (PD) is the repeated sudden occurrence of panic attacks, episodes characterized by psychological symptoms. Peripheral benzodiazepine receptor (PBR) is closely associated with personality traits for anxiety tolerance, and that it holds promise as a biological marker of stressful conditions. We have performed association analyses using the polymorphism to determine the PBR in PD. We screened the subjects for sequence variations within the 5' region, the coding region (exons 2-4), and the 3' noncoding region. One novel missense variant in exon 4, derived from the nucleotide transition in codon 162 (CGT --> CAT:485G > A) resulting in an arginine-to-histidine (Arg --> His) change, was detected in these subjects. The 485G > polymorphism of the PBR gene was analyzed in 91 PD patients and 178 controls. The genotypic and allelic analyses of the 485G > A revealed significant differences between the panic patients and the comparison subjects (P = 0.021 and 0.014, respectively). The present study provides new and important evidence that variation in the PBR gene influences susceptibility to PD.

  17. Do differences in Toxoplasma prevalence influence global variation in secondary sex ratio? Preliminary ecological regression study.

    PubMed

    Dama, Madhukar S; Martinec Nováková, Lenka; Flegr, Jaroslav

    2016-08-01

    Sex of the fetus is genetically determined such that an equal number of sons and daughters are born in large populations. However, the ratio of female to male births across human populations varies significantly. Many factors have been implicated in this. The theory that natural selection should favour female offspring under suboptimal environmental conditions implies that pathogens may affect secondary sex ratio (ratio of male to female births). Using regression models containing 13 potential confounding factors, we have found that variation of the secondary sex ratio can be predicted by seroprevalence of Toxoplasma across 94 populations distributed across African, American, Asian and European continents. Toxoplasma seroprevalence was the third strongest predictor of secondary sex ratio, β = -0·097, P < 0·01, after son preference, β = 0·261, P < 0·05, and fertility, β = -0·145, P < 0·001. Our preliminary results suggest that Toxoplasma gondii infection could be one of the most important environmental factors influencing the global variation of offspring sex ratio in humans. The effect of latent toxoplasmosis on public health could be much more serious than it is usually supposed to be. PMID:27350331

  18. Decadal variation of the Northern Hemisphere Annular Mode and its influence on the East Asian trough

    NASA Astrophysics Data System (ADS)

    Lu, Chunhui; Zhou, Botao; Ding, Yihui

    2016-06-01

    We analyze the decadal variation of the stratosphere-troposphere coupled system around the year 2000 by using the NCEP reanalysis-2 data. Specifically, the relationship between the Northern Hemisphere Annular Mode (NAM) and the tropospheric East Asian trough is investigated in order to find the effective stratospheric signals during cold air outbreaks in China. Statistical analyses and dynamic diagnoses both indicate that after 2000, increased stratospheric polar vortex disturbances occur and the NAM is mainly in negative phase. The tropospheric polar areas are directly affected by the polar vortex, and in the midlatitudes, the Ural blocking high and East Asian trough are more active, which lead to enhanced cold air activities in eastern and northern China. Further investigation reveals that under this circulation pattern, downward propagations of negative NAM index are closely related to the intensity variation of the East Asian trough. When negative NAM anomalies propagate down to the upper troposphere and reach a certain intensity (standardized NAM index less than-1), they result in apparent reinforcement of the East Asian trough, which reaches its maximum intensity about one week later. The northerly wind behind the trough transports cold air southward and eastward, and the range of influence and the intensity are closely associated with the trough location. Therefore, the NAM index can be used as a measure of the signals from the disturbed stratosphere to give some indication of cold air activities in China.

  19. [Variation characteristic in soil respiration of apple orchard and its biotic and abiotic influencing factors].

    PubMed

    Wang, Rui; Guo, Sheng-Li; Liu, Qing-Fang; Zhang, Yan-Jun; Jiang, Ji-Shao; Guo, Hui-Min; Li, Ru-Jian

    2014-05-01

    To evaluate the orchard variability of soil respiration and the response of soil respiration to its influencing factors is helpful for a deep understanding about the effects of converting cropland to apple orchard. A field experiment was conducted in the Changwu State Key Agro-Ecological Station. Soil respiration, soil temperature, soil moisture and roots biomasses were periodically measured in a mature apple orchard during 2011 and 2012. Soil respiration decreased as the distance from the trunk increased. The cumulative soil respiration in the 0.5 m-distance from the trunk was 20% and 31% higher than that in the 2 m-distance from the trunk, respectively in 2011 and 2012. The temperature sensitivity of soil respiration (Q10) was relatively lower in the 2 m-distance than that in the 0. 5 m-distance in both years. Soil temperature and soil moisture were slightly higher in the 2 m-distance, but there was no significant difference between the 2 m-distance and the 0. 5 m-distance. Soil respiration and soil temperature showed a significant exponential relationship, but there was no positive correlation between soil moisture and soil respiration. Soil temperature changes can explain seasonal variation of soil respiration well, but it could not explain its spatial variability. Root density was an important factor for the spatial variability of soil respiration and Q15. Variation of soil respiration coefficient was 23% -31%. Therefore, the distance from the trunk should be considered when estimating orchards soil respiration.

  20. Influence of seasonal variation on the phenology and liriodenine content of Annona lutescens (Annonaceae).

    PubMed

    Castro-Moreno, Marisol; Tinoco-Ojangurén, Clara Leonor; Cruz-Ortega, Ma Del Rocío; González-Esquinca, Alma Rosa

    2013-07-01

    Annona lutescens Saff. (Annonaceae) grows as a native tree in Chiapas, Mexico in Tropical Dry Forest habitat. Like most Annonaceae, it biosynthesizes benzylisoquinoline alkaloids, mostly liriodenine. To determine the influence of seasonal changes in the accumulation of liriodenine, the monthly variation of liriodenine content in roots, stems and leaves of mature and young trees was observed. These parts of young and mature A. lutescens trees were collected monthly over a 1 year period and the alkaloids were extracted; the liriodenine was quantified by high-resolution liquid chromatography. The phenological stages of the species were also assessed (leaf development, flowering and fruiting) using the Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie (BBCH) scale. The analysis of both young and mature trees showed a significant increase in the liriodenine concentration occurs within roots during the dry season, which coincides with leaf fall. A significant decrease also occurred at the beginning of the rainy season (the period of leaf growth); the liriodenine content for the next rainy season did not reach the levels of the previous dry season. The climatic variation induced phenological and physiological changes in this species.

  1. Variation at Genes Influencing Facial Morphology Are Not Associated with Developmental Imprecision in Human Faces

    PubMed Central

    Windhager, Sonja; Schaschl, Helmut; Schaefer, Katrin; Mitteroecker, Philipp; Huber, Susanne; Wallner, Bernard; Fieder, Martin

    2014-01-01

    Facial asymmetries are commonly used as a proxy for human developmental imprecision resulting from inbreeding, and thus reduced genetic heterozygosity. Several environmental factors influence human facial asymmetry (e.g., health care, parasites), but the generalizability of findings on genetic stressors has been limited in humans by sample characteristics (island populations, endogamy) and indirect genetic assessment (inference from pedigrees). In a sample of 3215 adult humans from the Rotterdam Study, we therefore studied the relationship of facial asymmetry, estimated from nine mid-facial landmarks, with genetic variation at 102 single nucleotide polymorphism (SNP) loci recently associated with facial shape variation. We further tested whether the degree of individual heterozygosity is negatively correlated with facial asymmetry. An ANOVA tree regression did not identify any SNP relating to either fluctuating asymmetry or total asymmetry. In a general linear model, only age and sex—but neither heterozygosity nor any SNP previously reported to covary with facial shape—was significantly related to total or fluctuating asymmetry of the midface. Our study does not corroborate the common assumption in evolutionary and behavioral biology that morphological asymmetries reflect heterozygosity. Our results, however, may be affected by a relatively small degree of inbreeding, a relatively stable environment, and an advanced age in the Rotterdam sample. Further large-scale genetic studies, including gene expression studies, are necessary to validate the genetic and developmental origin of morphological asymmetries. PMID:24914781

  2. CFD investigation of the influence of volute geometrical variations on hydrodynamic characteristics of circulator pump

    NASA Astrophysics Data System (ADS)

    Wu, Denghao; Yuan, Shouqi; Ren, Yun; Mu, Jiegang; Yang, Youdong; Liu, Jian

    2016-03-01

    Improper design of volute geometry can be the main cause that leads to unsteady pressure pulsation and radial force in pumps. Therefore, it is important to understand the influence of volute geometrical parameters on hydrodynamic characteristics of pump and the mechanism. However, the existing studies are limited to investigate the influence of only one or two volute geometrical parameters each time, and a systematic study of the influence of the combinations of different volute geometrical parameters on the pump's hydrodynamic characteristics is missing. In this paper, a study on the understanding of the influence of volute geometrical variations on hydrodynamic characteristics of a high speed circulator pump by using computational fluid dynamics(CFD) technology is presented. Five main volute geometrical parameters D 3, A 8, α 0, φ 0 and R t are selected and 25 different volute configurations are generated by using design of experiments(DOE) method. The 3D unsteady flow numerical simulations, which are based on the SST k- w turbulence model and sliding mesh technique provided by CFX, are executed on the 25 different volute configurations. The hydraulic performance, pressure pulsation and unsteady radial force inside the pump at design condition are obtained and analyzed. It has been found that volute geometrical parameters D 3 and A 8 are major influence factors on hydrodynamic characteristics of the pump, while α 0, φ 0 and R t are minor influence factors. The minimum contribution from both D 3 and A 8 is 58% on head, and maximum contribution from both D 3 and A 8 is 90% on pressure pulsation. Regarding the pressure pulsation intensity, two peaks can be found. One is in the tongue area and the other is in the diffusor area. The contributions are around 60% from tongue and 25% from diffusor, respectively. The amplitude of pressure pulsation has a quadratic polynomial functional relationship with respect to D 3/ D 2 and A 8/ A 10, and fluctuating level of

  3. Altitudinal variation in egg retention and rates of embryonic development in oviparous Zootoca vivipara fits predictions from the cold-climate model on the evolution of viviparity.

    PubMed

    Rodríguez-Díaz, T; Braña, F

    2012-09-01

    The evolution of reptilian viviparity is favoured, according to the cold-climate hypothesis, at high latitudes or altitudes, where egg retention would entail thermal benefits for embryogenesis because of maternal thermoregulation. According to this hypothesis, and considering that viviparity would have evolved through a gradual increase in the extent of intrauterine egg retention, highland oviparous populations are expected to exhibit more advanced embryo development at oviposition than lowland populations. We tested for possible differences in the level of egg retention, embryo development time and thermal biology of oviparous Zootoca vivipara near the extreme altitudinal limits of the species distribution in the north of Spain (mean altitude for lowland populations, 235 m asl.; for highland populations, 1895 m asl.). Altitude influenced neither temperature of active lizards in the field nor temperature selected by lizards in a laboratory thermal gradient, and pregnant females selected lower temperatures in the thermal gradient than did males and nonpregnant females across altitudinal levels. Eggs from highland populations contained embryos more developed at the time of oviposition (Dufaure and Hubert's stages 33-35) than eggs of highland populations (stages 30-34) and partly because of this difference incubation time was shorter for highland embryos. When analysed for clutches from both altitudinal extremes at the same embryonic stage at oviposition (stage 33), again incubation time was shorter for highland populations, indicating genuine countergradient variation in developmental rate. Our results indicate that temperature is an environmental factor affecting the geographical distribution of different levels of egg retention in Z. vivipara, as predicted by the cold-climate hypothesis on the evolution of viviparity.

  4. Influence of rice black streaked dwarf virus on the ecological fitness of non-vector planthopper Nilaparvata lugens (Hemiptera: Delphacidae).

    PubMed

    Xu, Hong-Xing; He, Xiao-Chan; Zheng, Xu-Song; Yang, Ya-Jun; Lu, Zhong-Xian

    2014-08-01

    Rice black streak dwarf virus (RBSDV) is transmitted by the small brown planthopper (SBPH), Laodelphax striatellus (Fallen). Non-vector rice brown planthopper (BPH), Nilaparvata lugens (Stål), shares the same host rice plants with SBPH in paddy fields. The changes in nutritional composition of rice plants infected by RBSDV and the ecological fitness of BPH feeding on the infected plants were studied under both artificial climate chamber and field conditions. Contents of 16 detected amino acids and soluble sugar in RBSDV infected rice plants were higher than those in the healthy ones. On the diseased plants BPH had significantly higher nymphal survival rates, nymphal duration of the males, weight of the female adults, as well as egg hatchability compared to BPH being fed on healthy plants. However, there was no obvious difference in female nymph duration, longevity and fecundity. Defense enzymes (superoxidase dismutase, SOD and catalase, CAT) and detoxifying enzymes (carboxylesterase, CAE and glutathione S-transferase, GST) in BPH adults fed on diseased plants had markedly higher activities. The results indicate rice plants infected by RBSDV improved the ecological fitness of the brown planthopper, a serious pest but not a transmitter of the RBSDV virus.

  5. Influence of rice black streaked dwarf virus on the ecological fitness of non-vector planthopper Nilaparvata lugens (Hemiptera: Delphacidae).

    PubMed

    Xu, Hong-Xing; He, Xiao-Chan; Zheng, Xu-Song; Yang, Ya-Jun; Lu, Zhong-Xian

    2014-08-01

    Rice black streak dwarf virus (RBSDV) is transmitted by the small brown planthopper (SBPH), Laodelphax striatellus (Fallen). Non-vector rice brown planthopper (BPH), Nilaparvata lugens (Stål), shares the same host rice plants with SBPH in paddy fields. The changes in nutritional composition of rice plants infected by RBSDV and the ecological fitness of BPH feeding on the infected plants were studied under both artificial climate chamber and field conditions. Contents of 16 detected amino acids and soluble sugar in RBSDV infected rice plants were higher than those in the healthy ones. On the diseased plants BPH had significantly higher nymphal survival rates, nymphal duration of the males, weight of the female adults, as well as egg hatchability compared to BPH being fed on healthy plants. However, there was no obvious difference in female nymph duration, longevity and fecundity. Defense enzymes (superoxidase dismutase, SOD and catalase, CAT) and detoxifying enzymes (carboxylesterase, CAE and glutathione S-transferase, GST) in BPH adults fed on diseased plants had markedly higher activities. The results indicate rice plants infected by RBSDV improved the ecological fitness of the brown planthopper, a serious pest but not a transmitter of the RBSDV virus. PMID:23956237

  6. Health-related fitness in adolescents: underweight, and not only overweight, as an influencing factor. The AVENA study.

    PubMed

    Artero, E G; España-Romero, V; Ortega, F B; Jiménez-Pavón, D; Ruiz, J R; Vicente-Rodríguez, G; Bueno, M; Marcos, A; Gómez-Martínez, S; Urzanqui, A; González-Gross, M; Moreno, L A; Gutiérrez, A; Castillo, M J

    2010-06-01

    This study investigated differences in health-related fitness (20-m shuttle run, handgrip, bent arm hang, standing long jump, shuttle run 4 x 10 m and sit and reach tests) in 2474 Spanish adolescents (1196 boys and 1278 girls; age 13-18.5 years) classed as underweight, normal weight, overweight or obese according to body mass index. Body fat and fat-free mass were derived from skinfold thickness. The prevalence of underweight was higher than obesity in girls (4.8% vs 3.0%, respectively; P<0.05) and the opposite in boys (3.9% vs 5.8%, respectively; P<0.05). Underweight was associated with a higher performance in the bent arm hang test in girls (P<0.05) and a lower performance in handgrip in both genders (P<0.01) compared with normal weight. Overweight and obese adolescents presented a lower performance in 20-m shuttle run, bent arm hang, standing long jump and shuttle run 4 x 10 m tests (P<0.001), but a higher performance in handgrip strength (P<0.001) compared with normal weight. In weight-bearing tests, the association became non-significant after adjusting for fat mass. In conclusion, not only overweight and obesity but also underweight seem to be determinants of health-related fitness in adolescents. The associations could be related to differences in body composition.

  7. The influence of scan mode and circle fitting on tree stem detection, stem diameter and volume extraction from terrestrial laser scans

    NASA Astrophysics Data System (ADS)

    Pueschel, Pyare; Newnham, Glenn; Rock, Gilles; Udelhoven, Thomas; Werner, Willy; Hill, Joachim

    2013-03-01

    Terrestrial laser scanning (TLS) has been used to estimate a number of biophysical and structural vegetation parameters. Of these stem diameter is a primary input to traditional forest inventory. While many experimental studies have confirmed the potential for TLS to successfully extract stem diameter, the estimation accuracies differ strongly for these studies - due to differences in experimental design, data processing and test plot characteristics. In order to provide consistency and maximize estimation accuracy, a systematic study into the impact of these variables is required. To contribute to such an approach, 12 scans were acquired with a FARO photon 120 at two test plots (Beech, Douglas fir) to assess the effects of scan mode and circle fitting on the extraction of stem diameter and volume. An automated tree stem detection algorithm based on the range images of single scans was developed and applied to the data. Extraction of stem diameter was achieved by slicing the point cloud and fitting circles to the slices using three different algorithms (Lemen, Pratt and Taubin), resulting in diameter profiles for each detected tree. Diameter at breast height (DBH) was determined using both the single value for the diameter fitted at the nominal breast height and by a linear fit of the stem diameter vertical profile. The latter is intended to reduce the influence of outliers and errors in the ground level determination. TLS-extracted DBH was compared to tape-measured DBH. Results show that tree stems with an unobstructed view to the scanner can be successfully extracted automatically from range images of the TLS data with detection rates of 94% for Beech and 96% for Douglas fir. If occlusion of trees is accounted for stem detection rates decrease to 85% (Beech) and 84% (Douglas fir). As far as the DBH estimation is concerned, both DBH extraction methods yield estimates which agree with reference measurements, however, the linear fit based approach proved to be more

  8. Influence of variation potential on resistance of the photosynthetic machinery to heating in pea.

    PubMed

    Sukhov, Vladimir; Surova, Lyubov; Sherstneva, Oksana; Vodeneev, Vladimir

    2014-12-01

    Electrical signals [action potentials (APs) and variation potentials (VPs)] induced by local stimuli are a mechanism that underlies rapid plant response to environmental factors. Such signals induce a number of functional responses, including changes in photosynthesis. Ultimately, these responses are considered to increase plant resistance to stress factors, but this question has been poorly investigated. We studied the influence of VP on photosynthesis and resistance of the photosynthetic machinery to heating in leaves of pea (Pisum sativum). Localized burning induced a VP that decreased photosynthesis parameters [CO(2) assimilation rate and quantum yields of photosystem I (PSI) and photosystem II (PSII)]. The photosynthetic response was initiated by a decrease in photosynthesis dark-stage activity, which in turn increased resistance of PSI to heating. Three results supported this hypothesized mechanism: (1) the magnitude of VP-induced decrease in CO(2) assimilation and enhanced PSI resistance to heating were highly correlated; (2) the VP influence on PSI resistance to heating was suppressed under a low external CO(2) concentration and (3) decreasing external CO(2) concentration imitated the VP-induced photosynthetic response and increased PSI resistance to heating.

  9. Influence of Reservoir Operation on River Eco-hydrological Regime Variation

    NASA Astrophysics Data System (ADS)

    Chang, J.; Wang, Y.; Li, Y.

    2013-12-01

    With the development of reservoir, river hydrological situation has undergone great changes. Liujiaxia and Longyangxia reservoir which all have great regulation ability were constructed in the upper reaches above Lanzhou station of the Yellow River. In view of the Indicator of Hydrologic Alteration (IHA), the Range of Variability Approach ( RVA ) is used to calculate the eco- hydrological characteristic values and analyze the influence of different reservoir operating modes on the variation of eco-hydrological characteristics of the Yellow River upstream. On the whole, the hydrologic regime at each station downstream of the Liujiaxia reservoir has changed obviously, especially that at Lanzhou station. The overall degree of hydrologic alteration with single reservoir (Liujiaxia) was 72. 64%, and the hydrologic alteration degree with two reservoirs joint operation was 78. 90%. Both of them were belong to high change. Also, after joint operation of Liujiaxia and Longyangxia reservoir, the flow in flood season significantly reduce and the number of high and low flow reversals increase, which would influence the living condition of aquatic organism in the Yellow River, and greatly endanger the aquatic species' reproduction.

  10. Influence of Arabidopsis thaliana accessions on rhizobacterial communities and natural variation in root exudates

    PubMed Central

    Micallef, Shirley A.; Shiaris, Michael P.; Colón-Carmona, Adán

    2009-01-01

    Plant species is considered to be one of the most important factors in shaping rhizobacterial communities, but specific plant–microbe interactions in the rhizosphere are still not fully understood. Arabidopsis thaliana, for which a large number of naturally occurring ecotype accessions exist, lacks mycorrhizal associations and is hence an ideal model for rhizobacterial studies. Eight Arabidopsis accessions were found to exert a marked selective influence on bacteria associated with their roots, as determined by terminal-restriction fragment length polymorphism (T-RFLP) and ribosomal intergenic spacer analysis (RISA). Community differences in species composition and relative abundance were both significant (P <0.001). The eight distinct and reproducible accession-dependent community profiles also differed from control bulk soil. Root exudates of these variants were analysed by high performance liquid chromatography (HPLC) to try to establish whether the unique rhizobacterial assemblages among accessions could be attributed to plant-regulated chemical changes in the rhizosphere. Natural variation in root exudation patterns was clearly exhibited, suggesting that differences in exudation patterns among accessions could be influencing bacterial assemblages. Other factors such as root system architecture are also probably involved. Finally, to investigate the Arabidopsis rhizosphere further, the phylogenetic diversity of rhizobacteria from accession Cvi-0 is described. PMID:19342429

  11. Patient-specific factors influence somatic variation patterns in von Hippel–Lindau disease renal tumours

    PubMed Central

    Fei, Suzanne S.; Mitchell, Asia D.; Heskett, Michael B.; Vocke, Cathy D.; Ricketts, Christopher J.; Peto, Myron; Wang, Nicholas J.; Sönmez, Kemal; Linehan, W. Marston; Spellman, Paul T.

    2016-01-01

    Cancer development is presumed to be an evolutionary process that is influenced by genetic background and environment. In laboratory animals, genetics and environment are variables that can largely be held constant. In humans, it is possible to compare independent tumours that have developed in the same patient, effectively constraining genetic and environmental variation and leaving only stochastic processes. Patients affected with von Hippel–Lindau disease are at risk of developing multiple independent clear cell renal carcinomas. Here we perform whole-genome sequencing on 40 tumours from six von Hippel-Lindau patients. We confirm that the tumours are clonally independent, having distinct somatic single-nucleotide variants. Although tumours from the same patient show many differences, within-patient patterns are discernible. Single-nucleotide substitution type rates are significantly different between patients and show biases in trinucleotide mutation context. We also observe biases in chromosome copy number aberrations. These results show that genetic background and/or environment can influence the types of mutations that occur. PMID:27174753

  12. Atomic force microscopy of crystalline insulins: the influence of sequence variation on crystallization and interfacial structure.

    PubMed Central

    Yip, C M; Brader, M L; DeFelippis, M R; Ward, M D

    1998-01-01

    The self-association of proteins is influenced by amino acid sequence, molecular conformation, and the presence of molecular additives. In the presence of phenolic additives, LysB28ProB29 insulin, in which the C-terminal prolyl and lysyl residues of wild-type human insulin have been inverted, can be crystallized into forms resembling those of wild-type insulins in which the protein exists as zinc-complexed hexamers organized into well-defined layers. We describe herein tapping-mode atomic force microscopy (TMAFM) studies of single crystals of rhombohedral (R3) LysB28ProB29 that reveal the influence of sequence variation on hexamer-hexamer association at the surface of actively growing crystals. Molecular scale lattice images of these crystals were acquired in situ under growth conditions, enabling simultaneous identification of the rhombohedral LysB28ProB29 crystal form, its orientation, and its dynamic growth characteristics. The ability to obtain crystallographic parameters on multiple crystal faces with TMAFM confirmed that bovine and porcine insulins grown under these conditions crystallized into the same space group as LysB28ProB29 (R3), enabling direct comparison of crystal growth behavior and the influence of sequence variation. Real-time TMAFM revealed hexamer vacancies on the (001) terraces of LysB28ProB29, and more rounded dislocation noses and larger terrace widths for actively growing screw dislocations compared to wild-type bovine and porcine insulin crystals under identical conditions. This behavior is consistent with weaker interhexamer attachment energies for LysB28ProB29 at active growth sites. Comparison of the single crystal x-ray structures of wild-type insulins and LysB28ProB29 suggests that differences in protein conformation at the hexamer-hexamer interface and accompanying changes in interhexamer bonding are responsible for this behavior. These studies demonstrate that subtle changes in molecular conformation due to a single sequence

  13. Variations in methanobactin structure influences copper utilization by methane-oxidizing bacteria

    PubMed Central

    El Ghazouani, Abdelnasser; Baslé, Arnaud; Gray, Joe; Graham, David W.; Firbank, Susan J.; Dennison, Christopher

    2012-01-01

    Methane-oxidizing bacteria are nature’s primary biological mechanism for suppressing atmospheric levels of the second-most important greenhouse gas via methane monooxygenases (MMOs). The copper-containing particulate enzyme is the most widespread and efficient MMO. Under low-copper conditions methane-oxidizing bacteria secrete the small copper-binding peptide methanobactin (mbtin) to acquire copper, but how variations in the structures of mbtins influence copper metabolism and species selection are unknown. Methanobactins have been isolated from Methylocystis strains M and hirsuta CSC1, organisms that can switch to using an iron-containing soluble MMO when copper is limiting, and the nonswitchover Methylocystis rosea. These mbtins are shorter, and have different amino acid compositions, than the characterized mbtin from Methylosinus trichosporium OB3b. A coordinating pyrazinedione ring in the Methylocystis mbtins has little influence on the Cu(I) site structure. The Methylocystis mbtins have a sulfate group that helps stabilize the Cu(I) forms, resulting in affinities of approximately 1021 M-1. The Cu(II) affinities vary over three orders of magnitude with reduction potentials covering approximately 250 mV, which may dictate the mechanism of intracellular copper release. Copper uptake and the switchover from using the iron-containing soluble MMO to the copper-containing particulate enzyme is faster when mediated by the native mbtin, suggesting that the amino acid sequence is important for the interaction of mbtins with receptors. The differences in structures and properties of mbtins, and their influence on copper utilization by methane-oxidizing bacteria, have important implications for the ecology and global function of these environmentally vital organisms. PMID:22582172

  14. Thermal variation and factors influencing vertical migration behavior in Daphnia populations.

    PubMed

    Glaholt, Stephen P; Kennedy, Meghan L; Turner, Elizabeth; Colbourne, John K; Shaw, Joseph R

    2016-08-01

    The antipredator behavior diel vertical migration (DVM), common in aquatic keystone species Daphnia, involves daily migration from warmer surface waters before dawn to cooler deeper waters after dusk. Plasticity in Daphnia DVM behavior optimizes fitness via trade-offs between growth, reproduction, and predator avoidance. Migration behavior is affected by co-varying biotic and abiotic factors, including light, predator cues, and anthropogenic stressors making it difficult to determine each factor's individual contribution to the variation in this behavior. This study aims to better understand this ecologically significant behavior in Daphnia by: (1) determining how Daphnia pulicaria thermal preferences vary within and among natural populations; (2) distinguishing the role of temperature verses depth in Daphnia vertical migration; and (3) defining how two anthropogenic stressors (copper and nickel) impact Daphnia migratory behavior. Simulated natural lake stratification were constructed in 8L (0.5m tall, 14.5cm wide) water columns to monitor under controlled laboratory conditions the individual effects of temperature gradients, depth, and metal stressors on Daphnia vertical migration. Three major findings are reported. First, while no difference in thermal preference was found among the four populations studied, within lake populations variability among isolates was high. Second, decoupling temperature and depth revealed that depth was a better predictor of Daphnia migratory patterns over temperature. Third, exposure to environmentally relevant concentrations of copper or nickel inhibited classic DVM behavior. These findings revealed the high variability in thermal preference found within Daphnia populations, elucidated the individual roles that depth and temperature have on migratory behavior, and showed how copper and nickel can interfere with the natural response of Daphnia to fish predator cues. Thus contributing to the body of knowledge necessary to predict how

  15. Thermal variation and factors influencing vertical migration behavior in Daphnia populations.

    PubMed

    Glaholt, Stephen P; Kennedy, Meghan L; Turner, Elizabeth; Colbourne, John K; Shaw, Joseph R

    2016-08-01

    The antipredator behavior diel vertical migration (DVM), common in aquatic keystone species Daphnia, involves daily migration from warmer surface waters before dawn to cooler deeper waters after dusk. Plasticity in Daphnia DVM behavior optimizes fitness via trade-offs between growth, reproduction, and predator avoidance. Migration behavior is affected by co-varying biotic and abiotic factors, including light, predator cues, and anthropogenic stressors making it difficult to determine each factor's individual contribution to the variation in this behavior. This study aims to better understand this ecologically significant behavior in Daphnia by: (1) determining how Daphnia pulicaria thermal preferences vary within and among natural populations; (2) distinguishing the role of temperature verses depth in Daphnia vertical migration; and (3) defining how two anthropogenic stressors (copper and nickel) impact Daphnia migratory behavior. Simulated natural lake stratification were constructed in 8L (0.5m tall, 14.5cm wide) water columns to monitor under controlled laboratory conditions the individual effects of temperature gradients, depth, and metal stressors on Daphnia vertical migration. Three major findings are reported. First, while no difference in thermal preference was found among the four populations studied, within lake populations variability among isolates was high. Second, decoupling temperature and depth revealed that depth was a better predictor of Daphnia migratory patterns over temperature. Third, exposure to environmentally relevant concentrations of copper or nickel inhibited classic DVM behavior. These findings revealed the high variability in thermal preference found within Daphnia populations, elucidated the individual roles that depth and temperature have on migratory behavior, and showed how copper and nickel can interfere with the natural response of Daphnia to fish predator cues. Thus contributing to the body of knowledge necessary to predict how

  16. Untangling Teacher-Child Play Interactions: Do Teacher Education and Experience Influence "Good-Fit" Responses to Children's Play?

    ERIC Educational Resources Information Center

    Trawick-Smith, Jeffrey; Dziurgot, Tracy

    2010-01-01

    The purpose of this study was to determine if levels of teacher education and experience would influence how teachers respond to children's play needs in a preschool classroom. The interactions of eight teachers--three of whom were categorized as high education/high experience, three as low education/high experience, and two as low education/low…

  17. 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.

  18. Genetic variation in the serotonin transporter gene influences ERP old/new effects during recognition memory.

    PubMed

    Ross, Robert S; Medrano, Paolo; Boyle, Kaitlin; Smolen, Andrew; Curran, Tim; Nyhus, Erika

    2015-11-01

    Recognition memory is defined as the ability to recognize a previously encountered stimulus and has been associated with spatially and temporally distinct event-related potentials (ERPs). Allelic variations of the serotonin transporter gene (SLC6A4) have recently been shown to impact memory performance. Common variants of the serotonin transporter-linked polymorphic region (5HTTLPR) of the SLC6A4 gene result in long (l) and short (s) allelic variants with carriers of the s allele having lowered transcriptional efficiency. Thus, the current study examines the effects polymorphisms of the SLC6A4 gene have on performance and ERP amplitudes commonly associated with recognition memory. Electroencephalogram (EEG), genetic, and behavioral data were collected from sixty participants as they performed an item and source memory recognition task. In both tasks, participants studied and encoded 200 words, which were then mixed with 200 new words during retrieval. Participants were monitored with EEG during the retrieval portion of each memory task. EEG electrodes were grouped into four ROIs, left anterior superior, right anterior superior, left posterior superior, and right posterior superior. ERP mean amplitudes during hits in the item and source memory task were compared to correctly recognizing new items (correct rejections). Results show that s-carriers have decreased mean hit amplitudes in both the right anterior superior ROI 1000-1500ms post stimulus during the source memory task and the left anterior superior ROI 300-500ms post stimulus during the item memory task. These results suggest that individual differences due to genetic variation of the serotonin transporter gene influences recognition memory.

  19. Synergistic influences of phase, density, and climatic variation on the dynamics of fluctuating populations.

    PubMed

    Goswami, Varun R; Getz, Lowell L; Hostetler, Jeffrey A; Ozgul, Arpat; Oli, Madan K

    2011-08-01

    Although ecologists have long recognized that certain mammalian species exhibit high-amplitude, often multiannual, fluctuations in abundance, their causes have remained poorly understood and the subject of intense debate. A key contention has been the relative role of density-dependent and density-independent processes in governing population dynamics. We applied capture-mark-recapture analysis to 25 years of monthly trapping data from a fluctuating prairie vole Microtus ochrogaster population in Illinois, USA, to estimate realized population growth rates and associated vital rates (survival and recruitment) and modeled them as a function of vole density and density-independent climatic variation. We also tested for phase dependence and seasonality in the effects of the above processes. Variation in the realized population growth rate was best explained by phase-specific changes in vole density lagged by one month and mean monthly temperatures with no time lags. The underlying vital rates, survival and recruitment, were influenced by the additive and interactive effects of phase, vole density, and mean monthly temperatures. Our results are consistent with the observation that large-scale population fluctuations are characterized by phase-specific changes in demographic and physiological characteristics. Our findings also support the growing realization that the interaction between climatic variables and density-dependent factors may be a widespread phenomenon, and they suggest that the direction and magnitude of such interactive effects may be phase specific. We conclude that density-dependent and density-independent climatic variables work in tandem during each phase of density fluctuations to drive the dynamics of fluctuating populations. PMID:21905434

  20. Genetic variation in the serotonin transporter gene influences ERP old/new effects during recognition memory.

    PubMed

    Ross, Robert S; Medrano, Paolo; Boyle, Kaitlin; Smolen, Andrew; Curran, Tim; Nyhus, Erika

    2015-11-01

    Recognition memory is defined as the ability to recognize a previously encountered stimulus and has been associated with spatially and temporally distinct event-related potentials (ERPs). Allelic variations of the serotonin transporter gene (SLC6A4) have recently been shown to impact memory performance. Common variants of the serotonin transporter-linked polymorphic region (5HTTLPR) of the SLC6A4 gene result in long (l) and short (s) allelic variants with carriers of the s allele having lowered transcriptional efficiency. Thus, the current study examines the effects polymorphisms of the SLC6A4 gene have on performance and ERP amplitudes commonly associated with recognition memory. Electroencephalogram (EEG), genetic, and behavioral data were collected from sixty participants as they performed an item and source memory recognition task. In both tasks, participants studied and encoded 200 words, which were then mixed with 200 new words during retrieval. Participants were monitored with EEG during the retrieval portion of each memory task. EEG electrodes were grouped into four ROIs, left anterior superior, right anterior superior, left posterior superior, and right posterior superior. ERP mean amplitudes during hits in the item and source memory task were compared to correctly recognizing new items (correct rejections). Results show that s-carriers have decreased mean hit amplitudes in both the right anterior superior ROI 1000-1500ms post stimulus during the source memory task and the left anterior superior ROI 300-500ms post stimulus during the item memory task. These results suggest that individual differences due to genetic variation of the serotonin transporter gene influences recognition memory. PMID:26423665

  1. Annual variations of carbonaceous PM2.5 in Malaysia: influence by Indonesian peatland fires

    NASA Astrophysics Data System (ADS)

    Fujii, Y.; Tohno, S.; Amil, N.; Latif, M. T.; Oda, M.; Matsumoto, J.; Mizohata, A.

    2015-12-01

    In this study, we quantified carbonaceous PM2.5 in Malaysia through annual observations of PM2.5, focusing on organic compounds derived from biomass burning. We determined organic carbon (OC), elemental carbon and concentrations of solvent-extractable organic compounds (biomarkers derived from biomass burning sources and n-alkanes). We observed seasonal variations in the concentrations of pyrolyzed OC (OP), levoglucosan (LG), mannosan (MN), galactosan, syringaldehyde, vanillic acid (VA) and cholesterol. The average concentrations of OP, LG, MN, galactosan, VA and cholesterol were higher during the southwestern monsoon season (June-September) than during the northeastern monsoon season (December-March), and these differences were statistically significant. Conversely, the syringaldehyde concentration during the southwestern monsoon season was lower. The PM2.5 OP / OC4 mass ratio allowed distinguishing the seven samples, which have been affected by the Indonesian peatland fires (IPFs). In addition, we observed significant differences in the concentrations between the Indonesian peatland fire (IPF) and other samples of many chemical species. Thus, the chemical characteristics of PM2.5 in Malaysia appeared to be significantly influenced by IPFs during the southwestern monsoon season. Furthermore, we evaluated two indicators, the vanillic acid / syringic acid (VA / SA) and LG / MN mass ratios, which have been suggested as indicators of IPFs. The LG / MN mass ratio ranged from 14 to 22 in the IPF samples and from 11 to 31 in the other samples. Thus, the respective variation ranges partially overlapped. Consequently, this ratio did not satisfactorily reflect the effects of IPFs in Malaysia. In contrast, the VA / SA mass ratio may serve as a good indicator, since it significantly differed between the IPF and other samples. However, the OP / OC4 mass ratio provided more remarkable differences than the VA / SA mass ratio, offering an even better indicator. Finally, we

  2. The influence from synoptic weather on the variation of air pollution and pollen exposure

    NASA Astrophysics Data System (ADS)

    Grundström, Maria; Dahl, Åslög; Chen, Deliang; Pleijel, Håkan

    2014-05-01

    Exposure to elevated air pollution levels can make people more susceptible to allergies or result in more severe allergic reactions for people with an already pronounced sensitivity to pollen. The aim of this study was to investigate the relationships between urban air pollution (nitrogen oxides, ozone and particles) and airborne Betula pollen in Gothenburg, Sweden, during the pollen seasons for the years 2001-2012. Further, the influence from atmospheric weather pattern on pollen/pollution related risk, using Lamb Weather Types (LWT), was also considered. Daily LWTs were obtained by comparing the variation in atmospheric pressure from a 16 point grid over a given region on earth (scale ~1000km) and essentially describe the air mass movement for the region. They include two non-directional types, cyclonic (C) and anticyclonic (A) and eight directional types depending on the wind direction (N, NE, E... etc.). LWTs with dry and calm meteorological character e.g. limited precipitation and low to moderate wind speeds (A, NE, E, SE) were associated with strongly elevated air pollution and pollen levels where Betula was exceptionally high in LWTs NE and E. The co-variation between Betula pollen and ozone was strong and significant during situations with LWTs A, NE, E and SE. The most important conclusion from this study was that LWTs A, NE, E and SE were associated with high pollen and air pollution levels and can therefore be classified as high risk weather situations for combined air pollution and pollen exposure. Our study shows that LWTs have the potential to be developed into an objective tool for integrated air quality forecasting and a warning system for risk of high exposure situations.

  3. Understanding Host-Switching by Ecological Fitting.

    PubMed

    Araujo, Sabrina B L; Braga, Mariana Pires; Brooks, Daniel R; Agosta, Salvatore J; Hoberg, Eric P; von Hartenthal, Francisco W; Boeger, Walter A

    2015-01-01

    Despite the fact that parasites are highly specialized with respect to their hosts, empirical evidence demonstrates that host switching rather than co-speciation is the dominant factor influencing the diversification of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing ecological specialists to host-switch readily. That proposal is tested herein using an individual-based model of host switching. The model considers a parasite species exposed to multiple host resources. Through time host range expansion can occur readily without the prior evolution of novel genetic capacities. It also produces non-linear variation in the size of the fitness space. The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later. The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process. PMID:26431199

  4. Understanding Host-Switching by Ecological Fitting

    PubMed Central

    Araujo, Sabrina B. L.; Braga, Mariana Pires; Brooks, Daniel R.; Agosta, Salvatore J.; Hoberg, Eric P.; von Hartenthal, Francisco W.; Boeger, Walter A.

    2015-01-01

    Despite the fact that parasites are highly specialized with respect to their hosts, empirical evidence demonstrates that host switching rather than co-speciation is the dominant factor influencing the diversification of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing ecological specialists to host-switch readily. That proposal is tested herein using an individual-based model of host switching. The model considers a parasite species exposed to multiple host resources. Through time host range expansion can occur readily without the prior evolution of novel genetic capacities. It also produces non-linear variation in the size of the fitness space. The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later. The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process. PMID:26431199

  5. Monitoring water storage variations in the vadose zone with gravimeters - quantifying the influence of observatory buildings

    NASA Astrophysics Data System (ADS)

    Reich, Marvin; Güntner, Andreas; Mikolaj, Michal; Blume, Theresa

    2016-04-01

    Time-lapse ground-based measurements of gravity have been shown to be sensitive to water storage variations in the surroundings of the gravimeter. They thus have the potential to serve as an integrative observation of storage changes in the vadose zone. However, in almost all cases of continuous gravity measurements, the gravimeter is located within a building which seals the soil beneath it from natural hydrological processes like infiltration and evapotranspiration. As water storage changes in close vicinity of the gravimeter have the strongest influence on the measured signal, it is important to understand the hydrology in the unsaturated soil zone just beneath the impervious building. For this reason, TDR soil moisture sensors were installed in several vertical profiles up to a depth of 2 m underneath the planned new gravimeter building at the Geodetic Observatory Wettzell (southeast Germany). In this study, we assess the influence of the observatory building on infiltration and subsurface flow patterns and thus the damping effect on gravimeter data in a two-way approach. Firstly, soil moisture time series of sensors outside of the building area are correlated with corresponding sensors of the same depth beneath the building. The resulting correlation coefficients, time lags and signal to noise relationships are used to find out how and where infiltrating water moves laterally beneath the building and towards its centre. Secondly, a physically based hydrological model (HYDRUS) with high discretization in space and time is set up for the 20 by 20 m area around and beneath the gravimeter building. The simulated spatial distribution of soil moisture in combination with the observed point data help to identify where and to what extent water storage changes and thus mass transport occurs beneath the building and how much this differs to the dynamics of the surroundings. This allows to define the umbrella space, i.e., the volume of the vadose zone where no mass

  6. Influences of normobaric hypoxia training on physical fitness and metabolic risk markers in overweight to obese subjects.

    PubMed

    Wiesner, Susanne; Haufe, Sven; Engeli, Stefan; Mutschler, Harry; Haas, Ute; Luft, Friedrich C; Jordan, Jens

    2010-01-01

    Previous studies suggested that hypoxia and exercise may have a synergistic effect on cardiovascular and metabolic risk factors. We conducted a single blind study in overweight to obese subjects to test the hypothesis that training under hypoxia (HG, n = 24, FiO(2) = 15%) results in similar or even greater improvement in body weight and metabolic risk markers compared with exercise under normoxia (NG, n = 21, FiO(2) = 21%). After an initial metabolic evaluation including incremental exercise testing, subjects trained in normoxic or hypoxic conditions thrice weekly over a 4-week period at a heart rate corresponding to 65% of maximum oxygen uptake (VO(2max)). The experimental groups were similar at the start of the investigation and weight stable during the training period. Subjects in the hypoxia group trained at a significantly lower workload (P < 0.05). Yet, both groups showed similar improvements in VO(2max) and time to exhaustion. Respiratory quotient and lactate at the anaerobic threshold as well as body composition improved more in the hypoxia group. We conclude that in obese subjects, training in hypoxia elicits a similar or even better response in terms of physical fitness, metabolic risk markers, and body composition at a lower workload. The fact that workload and, therefore, mechanic strain can be reduced in hypoxia could be particularly beneficial in obese patients with orthopedic comorbidities.

  7. Lateral variations in a tidally influenced Carnian to Early Norian transect in central Svalbard

    NASA Astrophysics Data System (ADS)

    Husteli, Berit; Boxaspen, Marit Ann; Rosseland Knutsen, Eirik

    2014-05-01

    In Central Spitsbergen, 78 degrees north, at Deltaneset, a north facing beach cliff makes the study of lateral changes of facies possible. The cliff is one km long, up to eight m high and consists of sandstones and mudstones of Carnian to early Norian age. They belong to the Isfjorden Member of the De Geerdalen Formation and are equivalent to the Snadd Formation in the Barents Sea. These formations are interesting due to potential storage of CO2 and a northward expanding petroleum exploration. Younger strata are continually exposed from east to west due to a dip towards southwest. The vertical succession is undisturbed. Regional studies have shown that the formation is deposited in a westwards prograding deltaic Carnian coastline. Individual units resolved from seismic analysis exhibit a lateral continuity on a scale of kilometers to tens of kilometers. However, studies show that the sedimentary rocks were deposited in a marginal marine environment, which start out in an offshore environment, pass through a wide variety of coastal sub-environments and end up in an alluvial setting with several palaeosols. This study focuses on the marginal area where frequent fluctuations of sea level is evident, due to the recording of recurrent cycles of marine incursions capped by paleosols. It is likely that the preservation of the paleosol is made possible due to transgressions that periodically initiated an onset of a more aggradational depositional style, before the regional prograding pattern catches up and culminates in another prolonged sub aerial exposure. In addition, characteristics such as abundant mud drapes, cyclic mudstone intervals in sandstone and current reversals suggest that the palaeoenvironment was tidally influenced. A tidally influenced coastal environment is prone to be more complicated in terms of sedimentary heterogeneities than a plain wave or river-dominated environment. These variations are in general beyond seismic resolution.

  8. Pollinator visitation patterns strongly influence among-flower variation in selfing rate

    PubMed Central

    Karron, Jeffrey D.; Holmquist, Karsten G.; Flanagan, Rebecca J.; Mitchell, Randall J.

    2009-01-01

    Background and Aims Adjacent flowers on Mimulus ringens floral displays often vary markedly in selfing rate. We hypothesized that this fine-scale variation in mating system reflects the tendency of bumble-bee pollinators to probe several flowers consecutively on multiflower displays. When a pollinator approaches a display, the first flower probed is likely to receive substantial outcross pollen. However, since pollen carryover in this species is limited, receipt of self pollen should increase rapidly for later flowers. Here the first direct experimental test of this hypothesis is described. Methods In order to link floral visitation sequences with selfing rates of individual flowers, replicate linear arrays were established, each composed of plants with unique genetic markers. This facilitated unambiguous assignment of paternity to all sampled progeny. A single wild bumble-bee was permitted to forage on each linear array, recording the order of floral visits on each display. Once fruits had matured, 120 fruits were harvested (four flowers from each of five floral displays in each of six arrays). Twenty-five seedlings from each fruit were genotyped and paternity was unambiguously assigned to all 3000 genotyped progeny. Key Results The order of pollinator probes on Mimulus floral displays strongly and significantly influenced selfing rates of individual fruits. Mean selfing rates increased from 21 % for initial probes to 78 % for the fourth flower probed on each display. Conclusions Striking among-flower differences in selfing rate result from increased deposition of geitonogamous (among-flower, within-display) self pollen as bumble-bees probe consecutive flowers on each floral display. The resulting heterogeneity in the genetic composition of sibships may influence seedling competition and the expression of inbreeding depression. PMID:19218584

  9. The influence of variations in biophysical conditions on hemolysis near ultrasonically activated gas-filled micropores

    SciTech Connect

    Miller, D.L.; Thomas, R.M. )

    1990-05-01

    Hemolysis induced by 1.9-MHz ultrasound in 0.5% suspensions of canine erythrocytes with 3.7-{mu}m-diam micropore-trapped gas bodies was investigated for a variety of biophysical conditions. For isotonic media, hemolysis increased with exposure duration but did not greatly change with exposure temperature, or prior heat treatment. The temperature results were especially interesting because increased temperatures might have been expected to increase the sensitivity of the cells to the ultrasonically activated gas bodies. Variations in osmolarity had little influence on the results. Increasing the viscosity of the medium decreased the effect, and this did not seem to depend on the molecular weight of the dextran additive. A medium with elevated mass density seemed to increase the effectiveness of the exposures. This condition eliminated the density difference between the cells and the medium, and might have been expected to reduce the effectiveness of the exposures, because the radiation force, which theoretically gathers cells to the gas bodies, is minimized for such conditions. This information should aid in developing refinements to the theoretical understanding of low-intensity ultrasonic bioeffects.

  10. Small-scale environmental variation influences whether coral-dwelling fish promote or impede coral growth.

    PubMed

    Chase, T J; Pratchett, M S; Walker, S P W; Hoogenboom, M O

    2014-12-01

    Mutualistic symbioses are ubiquitous in nature and facilitate high biodiversity and productivity of ecosystems by enhancing the efficiency of energy and nutrient use within ecological communities. For example, small groups of fish that inhabit coral colonies in reef ecosystems potentially enhance coral growth through defense from coral predators, aeration of coral tissue and nutrient provisioning. This study examines whether the prevalence and consequences of fish-coral interactions vary among sites with different environmental conditions in a coral reef lagoon, using the humbug damselfish Dascyllus aruanus and its preferred coral host Pocillopora damicornis as a study system. Using a field experiment, we tested the site-specific effects of D. aruanus on coral growth, and show that the cost-benefit ratio for corals hosting fish varies with local environmental variation. Results of this study also demonstrate that fish prefer to inhabit coral colonies with particular branch-spacing characteristics, and that the local abundance of D. aruanus influences the proportion of coral colonies within a site that are occupied by fish rather than increasing the number of fish per colony. We also show that corals consistently benefit from hosting D. aruanus via defense from predation by corallivorous butterflyfish, regardless of local environmental conditions. These findings highlight the need to consider the potential for multiple scale- and state-dependent interaction effects when examining the ecology of fish-coral associations. We suggest that fluctuating cost-benefit ratios for species interactions may contribute to the maintenance of different colony phenotypes within coral populations.

  11. Individual variation in the propensity to attribute incentive salience to a food cue: influence of sex.

    PubMed

    Pitchers, Kyle K; Flagel, Shelly B; O'Donnell, Elizabeth G; Woods, Leah C Solberg; Sarter, Martin; Robinson, Terry E

    2015-02-01

    There is considerable individual variation in the propensity of animals to attribute incentive salience to discrete reward cues, but to date most of this research has been conducted in male rats. The purpose of this study was to determine whether sex influences the propensity to attribute incentive salience to a food cue, using rats from two different outbred strains (Sprague-Dawley [SD] and Heterogeneous Stock [HS]). The motivational value of a food cue was assessed in two ways: (i) by the ability of the cue to elicit approach toward it and (ii) by its ability to act as a conditioned reinforcer. We found that female SD rats acquired Pavlovian conditioned approach behavior slightly faster than males, but no sex difference was detected in HS rats, and neither strain showed a sex difference in asymptotic performance of approach behavior. Moreover, female approach behavior did not differ across estrous cycle. Compared to males, females made more active responses during the test for conditioned reinforcement, although they made more inactive responses as well. We conclude that although there are small sex differences in performance on these tasks, these are probably not due to a notable sex difference in the propensity to attribute incentive salience to a food cue. PMID:25446811

  12. Lead in Chinese villager house dust: Geographical variation and influencing factors.

    PubMed

    Bi, Xiangyang; Liu, Jinling; Han, Zhixuan; Yang, Wenlin

    2015-12-01

    House dust has been recognized as an important contributor to Pb exposure of children. Here we conducted a comprehensive study to investigate geographical variation of Pb in Chinese villager house dust. The influences of outdoor soil Pb concentrations, dates of construction, house decoration materials, heating types, and site specific pollution on Pb concentrations in house dust were evaluated. The concentrations of Pb in 477 house dust samples collected from twenty eight areas throughout China varied from 12 to 2510 mg/kg, with a median concentration of 42 mg/kg. The median Pb concentrations in different geographical areas ranged from 16 (Zhangjiakou, Hebei) to 195 mg/kg (Loudi, Hunan). No correlations were found between the house dust Pb concentrations and the age of houses, as well as house decoration materials. Whereas outdoor soil, coal combustion, and site specific pollution may be potential Pb sources. Principal component analysis (PCA) confirmed that elemental compositions of the house dust were controlled by both anthropogenic and geogenic sources. Using scanning electron microscopy (SEM), the Pb bearing particles in the house dust were also studied.

  13. Influence of environmental variation on symbiotic bacterial communities of two temperate sponges.

    PubMed

    Cárdenas, César A; Bell, James J; Davy, Simon K; Hoggard, Michael; Taylor, Michael W

    2014-06-01

    Sponges are an important component of temperate subtidal marine ecosystems, with a range of important functional roles and extensive symbiotic relationships with microorganisms. However, much remains unknown about their relationships with these symbiotic microorganisms, and specifically, the role that these symbionts play in sponge physiology, feeding and adaptation to local environmental conditions. Changes in environmental factors may alter relationships between sponges and their symbionts, which could conceivably influence the abundance and distribution patterns of some temperate sponge species. Here, we analyzed the effect of transplantation of sponges between different habitats to test the effect of changes in environmental conditions on the stability of the bacterial communities in specimens of Tethya bergquistae and Ecionemia alata, based on pyrosequencing of amplified 16S rRNA genes. Bacterial communities differed markedly between the two host species. While some morphological changes were observed in transplanted sponges, transplantation had little overall effect on sponge-associated bacterial communities at either phylum or 97%-OTU level. Our results show the importance of host species and also the stability of sponge-associated bacterial communities under environmental variation.

  14. [Soil respiration variations in winter wheat field in different previous crops and its influencing factors].

    PubMed

    Hao, Wang-Lin; Liang, Yin-Li; Wu, Xing; Lin, Xing-Jun; Zhu, Yan-Li; Luo, An-Rong

    2011-11-01

    This study was to define the Variations of soil respiration, the response of influence factors to soil respiration and carbon sink in the total growing season, in winter wheat field of different previous crops. The results showed that: (1) as soil depth increases, the response of temperature to soil respiration rate also increased with a lag; (2) the soil respiration rate was quadric to soil moisture, phosphorus, potassium, soil urease activity, soil temperature, soil moisture as the main factors had an effect on soil respiration rate; soil temperature had the stronger effect on soil respiration rate when potassium had the weaker effect on soil respiration rate; (3) the average carbon emission rate in wheat filed of different previous crops showed as follow: Pepper of previous crops > celery of previous crops > corn of previous crops > eggplant of previous crops. The intensity of carbon "sink" displayed as follow: eggplant of previous crops > celery of previous crops > corn of previous crops > pepper of previous crops. As for the trials of this study, although the soil respiration rate is highest in the winter wheat filed of previous pepper, the amount of carbon fixed is the most. Its ratio of net primary productivity (NPP) and soil carbon release quantity was highest, so carbon sink was the strongest. If rotation planting was arranged according to the purpose of increasing carbon sink and reducing carbon emissions, pepper was relatively appropriate stubbles crop, followed by corn crop, celery and eggplant.

  15. Influence of barriers to movement on within-watershed genetic variation of coastal cutthroat trout

    USGS Publications Warehouse

    Wofford, John E.B.; Gresswell, Robert E.; Banks, M.A.

    2005-01-01

    Because human land use activities often result in increased fragmentation of aquatic and terrestrial habitats, a better understanding of the effects of fragmentation on the genetic heterogeneity of animal populations may be useful for effective management. We used eight microsatellites to examine the genetic structure of coastal cutthroat trout (Oncorhynchus clarki clarki) in Camp Creek, an isolated headwater stream in western Oregon. Our objectives were to determine if coastal cutthroat trout were genetically structured within streams and to assess the effects of natural and anthropogenic barriers on coastal cutthroat trout genetic variation. Fish sampling occurred at 10 locations, and allele frequencies differed significantly among all sampling sections. Dispersal barriers strongly influenced coastal cutthroat trout genetic structure and were associated with reduced genetic diversity and increased genetic differentiation. Results indicate that Camp Creek coastal cutthroat trout exist as many small, partially independent populations that are strongly affected by genetic drift. In headwater streams, barriers to movement can result in genetic and demographic isolation leading to reduced coastal cutthroat trout genetic diversity, and potentially compromising long-term population persistence. When habitat fragmentation eliminates gene flow among small populations, similar results may occur in other species.

  16. Influence of fluid-property variation on turbulent convective heat transfer in vertical annular channel flows.

    SciTech Connect

    D. M. McEligot; J. H. Bae; J. Y. Yoo; H. Choi; James R. Wolf

    2005-10-01

    Influence of strongly-varying properties of supercritical-pressure fluids on turbulent convective heat transfer is investigated using direct numerical simulation. We consider thermally-developing upward flows in a vertical annular channel where the inner wall is heated with a constant heat flux and the outer wall is insulated. CO2 is chosen as the working fluid at a pressure to 8 Mpa, and the inlet Reynolds number based on the channel hydraulic diameter and the bulk velocity is Re0 = 8900. It is shown that turbulent convective heat transfer characteristics of supercritical flow are significantly different from those of constant-property flow mainly due to spatial and temporal variations of fluid density. Non-uniform density distribution causes fluid particles to be accelerated either by expansion or buoyancy force near the heated wall, while temporal density fluctuations change the transport characteristics of turbulent heat and momentum via the buoyancy production terms arising from the correlations such as p1u1x, p1u1r and p1h1. Among various turbulence statistics, the streamwise turbulent heat flux shows a very peculiar transitional behavior due to the buoyancy effect, changing both in sign and magnitude. Consequently, a non-monotonic temperature distribution is developed in the flow direction, causing severe impairment of heat transfer in supercritical flows.

  17. Seasonal variation and factors influencing perchlorate in water, snow, soil and corns in Northeastern China.

    PubMed

    Ye, Long; You, Hong; Yao, Jie; Kang, Xi; Tang, Lu

    2013-03-01

    Seasonal variation and influencing factors of perchlorate in snow, surface soil, rain, surface water, groundwater and corn were studied. Seven hundreds and seventy samples were collected in different periods in Harbin and its vicinity, China. Perchlorate concentrations were analyzed by ion chromatography-electrospray mass spectrometry. Results indicate that fireworks and firecrackers display from the Spring Festival to the Lantern Festival (February 2, 2011-February 17, 2011) can result in the occurrence of perchlorate in surface soil and snow. Perchlorate distribution is affected by wind direction in winter. Melting snow which contained perchlorate can dissolve perchlorate in surface soil, and then perchlorate can percolate into groundwater so that perchlorate concentrations in groundwater increased in spring. Perchlorate concentrations in groundwater and surface water decrease after rainy season in summer. Groundwater samples collected in the floodplain areas of the Songhua River and the Ashi River contained higher perchlorate concentrations than that far away with the rivers. The corns have the ability to accumulate perchlorate. PMID:23287025

  18. Day and night trophic variations of dominant fish species in a lagoon influenced by freshwater seeps.

    PubMed

    Arceo-Carranza, D; Vega-Cendejas, M E; Hernández de Santillana, M

    2013-01-01

    The aim of this study was to determine the trophic structure and nycthemeral variations in the diet of dominant fish species (Ariopsis felis, Bairdiella chrysoura, Micropogonias undulatus, Eucinostomus gula, Eucinostomus argenteus, Lagodon rhomboides and Sphoeroides testudineus) in Celestun Lagoon, a biosphere reserve located in the southern Gulf of Mexico, and influenced by freshwater seeps. A total of 1473 stomachs were analysed and nine trophic groups were recorded. Bray-Curtis analyses with analyses of similarity (ANOSIM) statistical tests were used to determine two groups of feeding guilds: zoobenthivores and omnivores, with significant differences between time and habitat. The relationships between fish feeding habits, size class and environmental variables were investigated using canonical correspondence analysis (CCA). Most of the species showed a low niche breadth with high specialization towards amphipod consumption, with the exception of L. rhomboides (0·60), which indicated generalist feeding. This study in a protected area is an important source of information for drawing up conservation policies in relation to the management of aquatic resources, and will aid in the establishment of priority areas for conservation.

  19. Differences in Muscle Activity During Cable Resistance Training Are Influenced by Variations in Handle Types.

    PubMed

    Rendos, Nicole K; Heredia Vargas, Héctor M; Alipio, Taislaine C; Regis, Rebeca C; Romero, Matthew A; Signorile, Joseph F

    2016-07-01

    Rendos, NK, Heredia Vargas, HM, Alipio, TC, Regis, RC, Romero, MA, and Signorile, JF. Differences in muscle activity during cable resistance training are influenced by variations in handle types. J Strength Cond Res 30(7): 2001-2009, 2016-There has been a recent resurgence in the use of cable machines for resistance training allowing movements that more effectively simulate daily activities and sports-specific movements. By necessity, these devices require a machine/human interface through some type of handle. Considerable data from material handling, industrial engineering, and exercise training studies indicate that handle qualities, especially size and shape, can significantly influence force production and muscular activity, particularly of the forearm muscles, which affect the critical link in activities that require object manipulation. The purpose for this study was to examine the influence of three different handle conditions: standard handle (StandH), ball handle with the cable between the index and middle fingers (BallIM), and ball handle with the cable between the middle and ring fingers (BallMR), on activity levels (rmsEMG) of the triceps brachii lateral and long heads (TriHLat, TriHLong), brachioradialis (BR), flexor carpi radialis (FCR), extensor carpi ulnaris, and extensor digitorum (ED) during eight repetitions of standing triceps pushdown performed from 90° to 0° elbow flexion at 1.5 s per contractile stage. Handle order was randomized. No significant differences were seen for triceps or BR rmsEMG across handle conditions; however, relative patterns of activation did vary for the forearm muscles by handle condition, with more coordinated activation levels for the FCR and ED during the ball handle conditions. In addition, the rmsEMG for the ED was significantly higher during the BallIM than any other condition and during the BallMR than the StandH. These results indicate that the use of ball handles with the cable passing between different fingers

  20. Ozone reaction with interior building materials: Influence of diurnal ozone variation, temperature and humidity

    NASA Astrophysics Data System (ADS)

    Rim, Donghyun; Gall, Elliott T.; Maddalena, Randy L.; Nazaroff, William W.

    2016-01-01

    Elevated tropospheric ozone concentrations are associated with increased morbidity and mortality. Indoor ozone chemistry affects human exposure to ozone and reaction products that also may adversely affect health and comfort. Reactive uptake of ozone has been characterized for many building materials; however, scant information is available on how diurnal variation of ambient ozone influences ozone reaction with indoor surfaces. The primary objective of this study is to investigate ozone-surface reactions in response to a diurnally varying ozone exposure for three common building materials: ceiling tile, painted drywall, and carpet tile. A secondary objective is to examine the effects of air temperature and humidity. A third goal is to explore how conditioning of materials in an occupied office building might influence subsequent ozone-surface reactions. Experiments were performed at bench-scale with inlet ozone concentrations varied to simulate daytime (ozone elevated) and nighttime (ozone-free in these experiments) periods. To simulate office conditions, experiments were conducted at two temperatures (22 °C and 28 °C) and three relative humidity values (25%, 50%, 75%). Effects of indoor surface exposures were examined by placing material samples in an occupied office and repeating bench-scale characterization after exposure periods of 1 and 2 months. Deposition velocities were observed to be highest during the initial hour of ozone exposure with slow decrease in the subsequent hours of simulated daytime conditions. Daily-average ozone reaction probabilities for fresh materials are in the respective ranges of (1.7-2.7) × 10-5, (2.8-4.7) × 10-5, and (3.0-4.5) × 10-5 for ceiling tile, painted drywall, and carpet tile. The reaction probability decreases by 7%-47% across the three test materials after two 8-h periods of ozone exposure. Measurements with the samples from an occupied office reveal that deposition velocity can decrease or increase with time

  1. A Study of Korean EFL Learners' Apology Speech Acts: Strategy and Pragmatic Transfer Influenced by Sociolinguistic Variations.

    ERIC Educational Resources Information Center

    Yang, Tae-Kyoung

    2002-01-01

    Examines how apology speech act strategies frequently used in daily life are transferred in the framework of interlanguage pragmatics and sociolinguistics and how they are influenced by sociolinguistic variations such as social status, social distance, severity of offense, and formal or private relationships. (Author/VWL)

  2. Invasion fitness, inclusive fitness, and reproductive numbers in heterogeneous populations.

    PubMed

    Lehmann, Laurent; Mullon, Charles; Akçay, Erol; Van Cleve, Jeremy

    2016-08-01

    How should fitness be measured to determine which phenotype or "strategy" is uninvadable when evolution occurs in a group-structured population subject to local demographic and environmental heterogeneity? Several fitness measures, such as basic reproductive number, lifetime dispersal success of a local lineage, or inclusive fitness have been proposed to address this question, but the relationships between them and their generality remains unclear. Here, we ascertain uninvadability (all mutant strategies always go extinct) in terms of the asymptotic per capita number of mutant copies produced by a mutant lineage arising as a single copy in a resident population ("invasion fitness"). We show that from invasion fitness uninvadability is equivalently characterized by at least three conceptually distinct fitness measures: (i) lineage fitness, giving the average individual fitness of a randomly sampled mutant lineage member; (ii) inclusive fitness, giving a reproductive value weighted average of the direct fitness costs and relatedness weighted indirect fitness benefits accruing to a randomly sampled mutant lineage member; and (iii) basic reproductive number (and variations thereof) giving lifetime success of a lineage in a single group, and which is an invasion fitness proxy. Our analysis connects approaches that have been deemed different, generalizes the exact version of inclusive fitness to class-structured populations, and provides a biological interpretation of natural selection on a mutant allele under arbitrary strength of selection.

  3. Variations in leopard cat (Prionailurus bengalensis) skull morphology and body size: sexual and geographic influences.

    PubMed

    Sicuro, Fernando L; Oliveira, Luiz Flamarion B

    2015-01-01

    The leopard cat, Prionailurus bengalensis (Kerr, 1792), is one of the most widespread Asian cats, occurring in continental eastern and southeastern Asia. Since 1929, several studies have focused on the morphology, ecology, and taxonomy of leopard cats. Nevertheless, hitherto there has been no agreement on basic aspects of leopard cat biology, such as the presence or absence of sexual dimorphism, morphological skull and body differences between the eleven recognized subspecies, and the biogeography of the different morphotypes. Twenty measurements on 25 adult leopard cat skulls from different Asian localities were analyzed through univariate and multivariate statistical approaches. Skull and external body measurements from studies over the last 77 years were assembled and organized in two categories: full data and summary data. Most of this database comprises small samples, which have never been statistically tested and compared with each other. Full data sets were tested with univariate and multivariate statistical analyses; summary data sets (i.e., means, SDs, and ranges) were analyzed through suitable univariate approaches. The independent analyses of the data from these works confirmed our original results and improved the overview of sexual dimorphism and geographical morphological variation among subspecies. Continental leopard cats have larger skulls and body dimensions. Skulls of Indochinese morphotypes have broader and higher features than those of continental morphotypes, while individuals from the Sunda Islands have skulls with comparatively narrow and low profiles. Cranial sexual dimorphism is present in different degrees among subspecies. Most display subtle sex-related variations in a few skull features. However, in some cases, sexual dimorphism in skull morphology is absent, such as in P. b. sumatranus and P. b. borneoensis. External body measurement comparisons also indicate the low degree of sexual dimorphism. Apart from the gonads, the longer hind

  4. Variations in leopard cat (Prionailurus bengalensis) skull morphology and body size: sexual and geographic influences

    PubMed Central

    Oliveira, Luiz Flamarion B.

    2015-01-01

    The leopard cat, Prionailurus bengalensis (Kerr, 1792), is one of the most widespread Asian cats, occurring in continental eastern and southeastern Asia. Since 1929, several studies have focused on the morphology, ecology, and taxonomy of leopard cats. Nevertheless, hitherto there has been no agreement on basic aspects of leopard cat biology, such as the presence or absence of sexual dimorphism, morphological skull and body differences between the eleven recognized subspecies, and the biogeography of the different morphotypes. Twenty measurements on 25 adult leopard cat skulls from different Asian localities were analyzed through univariate and multivariate statistical approaches. Skull and external body measurements from studies over the last 77 years were assembled and organized in two categories: full data and summary data. Most of this database comprises small samples, which have never been statistically tested and compared with each other. Full data sets were tested with univariate and multivariate statistical analyses; summary data sets (i.e., means, SDs, and ranges) were analyzed through suitable univariate approaches. The independent analyses of the data from these works confirmed our original results and improved the overview of sexual dimorphism and geographical morphological variation among subspecies. Continental leopard cats have larger skulls and body dimensions. Skulls of Indochinese morphotypes have broader and higher features than those of continental morphotypes, while individuals from the Sunda Islands have skulls with comparatively narrow and low profiles. Cranial sexual dimorphism is present in different degrees among subspecies. Most display subtle sex-related variations in a few skull features. However, in some cases, sexual dimorphism in skull morphology is absent, such as in P. b. sumatranus and P. b. borneoensis. External body measurement comparisons also indicate the low degree of sexual dimorphism. Apart from the gonads, the longer hind

  5. Variations in leopard cat (Prionailurus bengalensis) skull morphology and body size: sexual and geographic influences.

    PubMed

    Sicuro, Fernando L; Oliveira, Luiz Flamarion B

    2015-01-01

    The leopard cat, Prionailurus bengalensis (Kerr, 1792), is one of the most widespread Asian cats, occurring in continental eastern and southeastern Asia. Since 1929, several studies have focused on the morphology, ecology, and taxonomy of leopard cats. Nevertheless, hitherto there has been no agreement on basic aspects of leopard cat biology, such as the presence or absence of sexual dimorphism, morphological skull and body differences between the eleven recognized subspecies, and the biogeography of the different morphotypes. Twenty measurements on 25 adult leopard cat skulls from different Asian localities were analyzed through univariate and multivariate statistical approaches. Skull and external body measurements from studies over the last 77 years were assembled and organized in two categories: full data and summary data. Most of this database comprises small samples, which have never been statistically tested and compared with each other. Full data sets were tested with univariate and multivariate statistical analyses; summary data sets (i.e., means, SDs, and ranges) were analyzed through suitable univariate approaches. The independent analyses of the data from these works confirmed our original results and improved the overview of sexual dimorphism and geographical morphological variation among subspecies. Continental leopard cats have larger skulls and body dimensions. Skulls of Indochinese morphotypes have broader and higher features than those of continental morphotypes, while individuals from the Sunda Islands have skulls with comparatively narrow and low profiles. Cranial sexual dimorphism is present in different degrees among subspecies. Most display subtle sex-related variations in a few skull features. However, in some cases, sexual dimorphism in skull morphology is absent, such as in P. b. sumatranus and P. b. borneoensis. External body measurement comparisons also indicate the low degree of sexual dimorphism. Apart from the gonads, the longer hind

  6. Annual variations of carbonaceous PM2.5 in Malaysia: influence by Indonesian peatland fires

    NASA Astrophysics Data System (ADS)

    Fujii, Y.; Tohno, S.; Amil, N.; Latif, M. T.; Oda, M.; Matsumoto, J.; Mizohata, A.

    2015-08-01

    In this study, we quantified carbonaceous PM2.5 in Malaysia through annual observations of PM2.5, focusing on organic compounds derived from biomass burning. We determined organic carbon (OC), elemental carbon (EC) and concentrations of solvent-extractable organic compounds (biomarkers derived from biomass burning sources and n-alkanes). We observed seasonal variations in the concentrations of pyrolyzed OC (OP), levoglucosan (LG), mannosan (MN), galactosan, syringaldehyde, vanillic acid (VA) and cholesterol. The average concentrations of OP, LG, MN, galactosan, VA and cholesterol were higher during the southwest monsoon season (June-September) than during the northeast monsoon season (December-March), and these differences were statistically significant. Conversely, the syringaldehyde concentration during the southwest monsoon season was lower. The PM2.5 OP/OC4 mass ratio allowed distinguishing the seven samples, which have been affected by the Indonesian peatland fires (IPFs). In addition, we observed significant differences in the concentrations between the IPF and other samples of many chemical species. Thus, the chemical characteristics of PM2.5 in Malaysia appeared to be significantly influenced by IPFs during the southwest monsoon season. Furthermore, we evaluated two indicators, the vanillic acid/syringic acid (VA/SA) and LG/MN mass ratios, which have been suggested as indicators of IPFs. The LG/MN mass ratio ranged from 14 to 22 in the IPF samples and from 11 to 31 in the other samples. Thus, the respective variation ranges partially overlapped. Consequently, this ratio did not satisfactorily reflect the effects of IPFs in Malaysia. In contrast, the VA/SA mass ratio may serve as a good indicator, since it significantly differed between the IPF and other samples. However, the OP/OC4 mass ratio provided more remarkable differences than the VA/SA mass ratio, offering an even better indicator. Finally, we extracted biomass burning emissions' sources such as IPF

  7. Genetic Variation of αENaC Influences Lung Diffusion During Exercise in Humans

    PubMed Central

    Baker, Sarah E.; Wheatley, Courtney M.; Cassuto, Nicholas A.; Foxx-Lupo, William T.; Sprissler, Ryan; Snyder, Eric M.

    2011-01-01

    Exercise, decompensated heart failure, and exposure to high altitude have been shown to cause symptoms of pulmonary edema in some, but not all, subjects, suggesting a genetic component to this response. Epithelial Na+ Channels (ENaC) regulate Na+ and fluid reabsorption in the alveolar airspace in the lung. An increase in number and/or activity of ENaC has been shown to increase lung fluid clearance. Previous work has demonstrated common functional genetic variants of the α-subunit of ENaC, including an A→T substitution at amino acid 663 (αA663T). We sought to determine the influence of the T663 variant of αENaC on lung diffusion at rest and at peak exercise in healthy humans. Thirty healthy subjects were recruited for study and grouped according to their SCNN1A genotype [n= 17vs.13, age=25±7vs.30±10yrs., BMI= 23±4vs.25±4kg/m2, V̇O2peak= 95±30vs.100±31%pred., mean±SD, for AA (homozygous for αA663) vs. AT/TT groups (at least one αT663), respectively]. Measures of the diffusing capacity of the lungs for carbon monoxide (DLCO), the diffusing capacity of the lungs for nitric oxide (DLNO), alveolar volume (VA), and alveolar-capillary membrane conductance (DM) were taken at rest and at peak exercise. Subjects expressing the AA polymorphism of ENaC showed a significantly greater percent increase in DLCO and DLNO, and a significantly greater decrease in systemic vascular resistance from rest to peak exercise than those with the AT/TT variant (DLCO=51±12vs.36±17%, DLNO=51±24vs.32±25%, SVR=−67±3vs.−50±8%, p<0.05). The AA ENaC group also tended to have a greater percent increase in DLCO/VA from rest to peak exercise, although this did not reach statistical significance (49±26vs.33±26%, p=0.08). These results demonstrate that genetic variation of the α-subunit of ENaC at amino acid 663 influences lung diffusion at peak exercise in healthy humans, suggesting differences in alveolar Na+ and, therefore, fluid handling. These findings could be important

  8. Metabarcoding reveals environmental factors influencing spatio-temporal variation in pelagic micro-eukaryotes.

    PubMed

    Brannock, Pamela M; Ortmann, Alice C; Moss, Anthony G; Halanych, Kenneth M

    2016-08-01

    Marine environments harbour a vast diversity of micro-eukaryotic organisms (protists and other small eukaryotes) that play important roles in structuring marine ecosystems. However, micro-eukaryote diversity is not well understood. Likewise, knowledge is limited regarding micro-eukaryote spatial and seasonal distribution, especially over long temporal scales. Given the importance of this group for mobilizing energy from lower trophic levels near the base of the food chain to larger organisms, assessing community stability, diversity and resilience is important to understand ecosystem health. Herein, we use a metabarcoding approach to examine pelagic micro-eukaryote communities over a 2.5-year time series. Bimonthly surface sampling (July 2009 to December 2011) was conducted at four locations within Mobile Bay (Bay) and along the Alabama continental shelf (Shelf). Alpha-diversity only showed significant differences in Shelf sites, with the greatest differences observed between summer and winter. Beta-diversity showed significant differences in community composition in relation to season and the Bay was dominated by diatoms, while the Shelf was characterized by dinoflagellates and copepods. The northern Gulf of Mexico is heavily influenced by the Mobile River Basin, which brings low-salinity nutrient-rich water mostly during winter and spring. Community composition was correlated with salinity, temperature and dissolved silicate. However, species interactions (e.g. predation and parasitism) may also contribute to the observed variation, especially on the Shelf, which warrants further exploration. Metabarcoding revealed clear patterns in surface pelagic micro-eukaryote communities that were consistent over multiple years, demonstrating how these techniques could be greatly beneficial to ecological monitoring and management over temporal scales. PMID:27238767

  9. Influences of Salinity Variations on Pore-water Flow in Salt Marshes

    NASA Astrophysics Data System (ADS)

    Shen, C.; Jin, G.; Xin, P.; Li, L.

    2013-12-01

    Salt marshes are important wetlands at the ocean-land interface with various ecological functions, serving as essential habitats for intertidal fauna, affecting the productivity of coastal waters through nutrient exchange, moderating the greenhouse gas emission and global warming. They are influenced by various physical and biogeochemical processes, among which the pore-water flow and associated solute transport processes play an important role in determining the material exchange between marsh soils and coastal water. Previous studies have examined such processes under the solo or combined effects of tidal fluctuation, evapotranspiration, stratigraphy, inland freshwater input, and topography. However, these investigations have neglected the spatial and temporal salinity variations in surface water and pore-water, which commonly exist in salt marshes due to the impacts of tidal inundation, precipitation and evapotranspiration. The density contrast between the surface water and pore-water may lead to significant modifications of the pore-water flow. Based on results from laboratory experiments and numerical simulations, we will demonstrate that: (1) under upward salinity gradients, flow instabilities in the form of fingers occur once the salinity contrast reaches a certain level, whereas under downward salinity gradients the system is stable; (2) because of the strong tidally-induced advective process occurring near the creek, both the number and size of fingers change gradually from the near-creek zone to the marsh interior; and (3) both upward and downward salinity gradients enhance the exchange between the surface water and pore-water in the marsh sediments. Keywords: Salt marshes; density effect; salinity gradient; pore-water flow; fingers. Instabilities under upward salinity gradient Stable system under downward salinity gradient

  10. The Influence of Social Systems on Patterns of Mitochondrial DNA Variation in Baboons.

    PubMed

    Kopp, G H; Ferreira da Silva, M J; Fischer, J; Brito, J C; Regnaut, S; Roos, C; Zinner, D

    2014-01-01

    Behavior is influenced by genes but can also shape the genetic structure of natural populations. Investigating this link is of great importance because behavioral processes can alter the genetic diversity on which selection acts. Gene flow is one of the main determinants of the genetic structure of a population and dispersal is the behavior that mediates gene flow. Baboons (genus Papio) are among the most intensely studied primate species and serve as a model system to investigate the evolution of social systems using a comparative approach. The general mammalian pattern of male dispersal and female philopatry has thus far been found in baboons, with the exception of hamadryas baboons (Papio hamadryas). As yet, the lack of data on Guinea baboons (Papio papio) creates a taxonomic gap in genus-wide comparative analyses. In our study we investigated the sex-biased dispersal pattern of Guinea baboons in comparison to hamadryas, olive, yellow, and chacma baboons using sequences of the maternally transmitted mitochondrial hypervariable region I. Analyzing whole-range georeferenced samples (N = 777), we found strong evidence for female-biased gene flow in Guinea baboons and confirmed this pattern for hamadryas baboons, as shown by a lack of genetic-geographic structuring. In addition, most genetic variation was found within and not among demes, in sharp contrast to the pattern observed in matrilocal primates including the other baboon taxa. Our results corroborate the notion that the Guinea baboons' social system shares some important features with that of hamadryas baboons, suggesting similar evolutionary forces have acted to distinguish them from all other baboons.

  11. Metabarcoding reveals environmental factors influencing spatio-temporal variation in pelagic micro-eukaryotes.

    PubMed

    Brannock, Pamela M; Ortmann, Alice C; Moss, Anthony G; Halanych, Kenneth M

    2016-08-01

    Marine environments harbour a vast diversity of micro-eukaryotic organisms (protists and other small eukaryotes) that play important roles in structuring marine ecosystems. However, micro-eukaryote diversity is not well understood. Likewise, knowledge is limited regarding micro-eukaryote spatial and seasonal distribution, especially over long temporal scales. Given the importance of this group for mobilizing energy from lower trophic levels near the base of the food chain to larger organisms, assessing community stability, diversity and resilience is important to understand ecosystem health. Herein, we use a metabarcoding approach to examine pelagic micro-eukaryote communities over a 2.5-year time series. Bimonthly surface sampling (July 2009 to December 2011) was conducted at four locations within Mobile Bay (Bay) and along the Alabama continental shelf (Shelf). Alpha-diversity only showed significant differences in Shelf sites, with the greatest differences observed between summer and winter. Beta-diversity showed significant differences in community composition in relation to season and the Bay was dominated by diatoms, while the Shelf was characterized by dinoflagellates and copepods. The northern Gulf of Mexico is heavily influenced by the Mobile River Basin, which brings low-salinity nutrient-rich water mostly during winter and spring. Community composition was correlated with salinity, temperature and dissolved silicate. However, species interactions (e.g. predation and parasitism) may also contribute to the observed variation, especially on the Shelf, which warrants further exploration. Metabarcoding revealed clear patterns in surface pelagic micro-eukaryote communities that were consistent over multiple years, demonstrating how these techniques could be greatly beneficial to ecological monitoring and management over temporal scales.

  12. Variation in annual runoff of the Jinghe River as influenced by climate change

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Chang, J.

    2014-12-01

    Variation in annual runoff of the Jinghe River as influenced by climate change Jian-xia Chang , Yimin WangInstitute of Water Resources and Hydroelectric Power, Xi'an University of Technology, Xi'an Shaanxi, China The characteristics of hydro-climatic changes in the Jinghe River Basin were analysed based on data collected at hydro-meteorological stations for the period 1960-2010. The analytical results revealed an increasing trend of the air temperature in the last several decades, but decreasing trends for streamflow and precipitation. This paper demonstrates the application of TOPMODEL, a rainfall-runoff model to simulate runoff of the Jinghe River Basin. Global climate model participating in Phase 5 of the Coupled Model Inter-comparison Project (CMIP5) has been used to project climate change of the Jinghe River Basin, by the year 2050. The projected temperature and precipitation were integrated into TOPMODEL to simulate runoff under future climate conditions. The projections show that the Jinghe River Basin tends to become warmer. Annual average maximum and minimum temperature would rise by 4.2℃ and 3.8 ℃ under RCP8.5 in the 2040s. Annual precipitation would also increase by 32 mm-68 mm under both scenarios, notably by 68 mm in 2030s under RCP8.5. The change in spring precipitation is most significant with an increase by 8%-29%. Annual average runoff is likely to increase about by -3%, -1% and 1% in the 2020s, 2030s and the 2040s under RCP 8.5 and by 2%, -8% and 15% under RCP 4.5 relative to the baseline (1990-2010).

  13. Cognitive fitness.

    PubMed

    Gilkey, Roderick; Kilts, Clint

    2007-11-01

    Recent neuroscientific research shows that the health of your brain isn't, as experts once thought, just the product of childhood experiences and genetics; it reflects your adult choices and experiences as well. Professors Gilkey and Kilts of Emory University's medical and business schools explain how you can strengthen your brain's anatomy, neural networks, and cognitive abilities, and prevent functions such as memory from deteriorating as you age. The brain's alertness is the result of what the authors call cognitive fitness -a state of optimized ability to reason, remember, learn, plan, and adapt. Certain attitudes, lifestyle choices, and exercises enhance cognitive fitness. Mental workouts are the key. Brain-imaging studies indicate that acquiring expertise in areas as diverse as playing a cello, juggling, speaking a foreign language, and driving a taxicab expands your neural systems and makes them more communicative. In other words, you can alter the physical makeup of your brain by learning new skills. The more cognitively fit you are, the better equipped you are to make decisions, solve problems, and deal with stress and change. Cognitive fitness will help you be more open to new ideas and alternative perspectives. It will give you the capacity to change your behavior and realize your goals. You can delay senescence for years and even enjoy a second career. Drawing from the rapidly expanding body of neuroscience research as well as from well-established research in psychology and other mental health fields, the authors have identified four steps you can take to become cognitively fit: understand how experience makes the brain grow, work hard at play, search for patterns, and seek novelty and innovation. Together these steps capture some of the key opportunities for maintaining an engaged, creative brain. PMID:18159786

  14. Influence of dominance, leptokurtosis and pleiotropy of deleterious mutations on quantitative genetic variation at mutation-selection balance.

    PubMed Central

    Zhang, Xu-Sheng; Wang, Jinliang; Hill, William G

    2004-01-01

    In models of maintenance of genetic variance (V (G)) it has often been assumed that mutant alleles act additively. However, experimental data show that the dominance coefficient varies among mutant alleles and those of large effect tend to be recessive. On the basis of empirical knowledge of mutations, a joint-effect model of pleiotropic and real stabilizing selection that includes dominance is constructed and analyzed. It is shown that dominance can dramatically alter the prediction of equilibrium V (G). Analysis indicates that for the situations where mutations are more recessive for fitness than for a quantitative trait, as supported by the available data, the joint-effect model predicts a significantly higher V (G) than does an additive model. Importantly, for what seem to be realistic distributions of mutational effects (i.e., many mutants may not affect the quantitative trait substantially but are likely to affect fitness), the observed high levels of genetic variation in the quantitative trait under strong apparent stabilizing selection can be generated. This investigation supports the hypothesis that most V (G) comes from the alleles nearly neutral for fitness in heterozygotes while apparent stabilizing selection is contributed mainly by the alleles of large effect on the quantitative trait. Thus considerations of dominance coefficients of mutations lend further support to our previous conclusion that mutation-selection balance is a plausible mechanism of the maintenance of the genetic variance in natural populations. PMID:15020447

  15. Association between sex ratio distortion and sexually antagonistic fitness consequences of female choice.

    PubMed

    Connallon, Tim; Jakubowski, Erin

    2009-08-01

    Genetic variation can be beneficial to one sex yet harmful when expressed in the other-a condition referred to as sexual antagonism. Because X chromosomes are transmitted from fathers to daughters, and sexually antagonistic fitness variation is predicted to often be X-linked, mates of relatively low-fitness males might produce high-fitness daughters whereas mates of high-fitness males produce low-fitness daughters. Such fitness consequences have been predicted to influence the evolution of female mating biases and the offspring sex ratio. Females might evolve to prefer mates that provide good genes for daughters or might adjust offspring sex ratios in favor of the sex with the highest relative fitness. We test these possibilities in a laboratory-adapted population of Drosophila melanogaster, and find that females preferentially mate with males carrying genes that are deleterious for daughters. Preferred males produce equal numbers of sons and daughters, whereas unpreferred males produce female-biased sex ratios. As a consequence, mean offspring fitness of unpreferred males is higher than offspring fitness of preferred males. This observation has several interesting implications for sexual selection and the maintenance of population genetic variation for fitness.

  16. The influence of RBE variations in a clinical proton treatment plan for a hypopharynx cancer

    NASA Astrophysics Data System (ADS)

    Tilly, N.; Johansson, J.; Isacsson, U.; Medin, J.; Blomquist, E.; Grusell, E.; Glimelius, B.

    2005-06-01

    Currently, most clinical range-modulated proton beams are assumed to have a fixed overall relative biological effectiveness (RBE) of 1.1. However, it is well known that the RBE increases with depth in the spread-out Bragg peak (SOBP) and becomes about 10% higher than mid-SOBP RBE at 2 mm from the distal edge (Paganetti 2003 Technol. Cancer Res. Treat. 2 413-26) and can reach values of 1.3-1.4 in vitro at the distal edge (Robertson et al 1975 Cancer 35 1664-77, Courdi et al 1994 Br. J. Radiol. 67 800-4). We present a fast method for applying a variable RBE correction with linear energy transfer (LET) dependent tissue-specific parameters based on the αref/βref ratios suitable for implementation in a treatment planning system. The influence of applying this variable RBE correction on a clinical multiple beam proton dose plan is presented here. The treatment plan is evaluated by RBE weighted dose volume histograms (DVHs) and the calculation of tumour control probability (TCP) and normal tissue complication probability (NTCP) values. The variable RBE correction yields DVHs for the clinical target volumes (CTVs), a primary advanced hypopharynx cancer and subclinical disease in the lymph nodes, that are slightly higher than those achieved by multiplying the absorbed dose with RBE = 1.1. Although, more importantly, the RBE weighted DVH for an organ at risk, the spinal cord is considerably increased for the variable RBE. As the spinal cord in this particular case is located 8 mm behind the planning target volume (PTV) and hence receives only low total doses, the NTCP values are zero in spite of the significant increase in the RBE weighted DVHs for the variable RBE. However, high NTCP values for the non-target normal tissue were obtained when applying the variable RBE correction. As RBE variations tend to be smaller for in vivo systems, this study—based on in vitro data since human tissue RBE values are scarce and have large uncertainties—can be interpreted as showing

  17. The influence of variations of elemental composition on the thermal properties of interstellar gas

    NASA Astrophysics Data System (ADS)

    Vasiliev, E. O.; Shchekinov, Yu. A.

    2016-10-01

    The mixing of metals and redistribution of the relative abundances of chemical elements in the interstellar medium often takes place on a timescale that exceeds the characteristic timescales for many other processes, such as ionization and the establishment of thermal equilibrium. Under these conditions, different regions of interstellar gas can have different thermal, chemical, and spectral properties. The paper considers the ionization kinetics and thermal regime of interstellar gas with variations in the relative elemental abundances. The thermal properties and observational (spectral) characteristics are most sensitive to variations of the relative abundance of carbon, oxygen, neon, and iron. The dynamic consequences of such variations are considered.

  18. Influence of seasonal variations in sea level on the salinity regime of a coastal groundwater-fed wetland.

    PubMed

    Wood, Cameron; Harrington, Glenn A

    2015-01-01

    Seasonal variations in sea level are often neglected in studies of coastal aquifers; however, they may have important controls on processes such as submarine groundwater discharge, sea water intrusion, and groundwater discharge to coastal springs and wetlands. We investigated seasonal variations in salinity in a groundwater-fed coastal wetland (the RAMSAR listed Piccaninnie Ponds in South Australia) and found that salinity peaked during winter, coincident with seasonal sea level peaks. Closer examination of salinity variations revealed a relationship between changes in sea level and changes in salinity, indicating that sea level-driven movement of the fresh water-sea water interface influences the salinity of discharging groundwater in the wetland. Moreover, the seasonal control of sea level on wetland salinity seems to override the influence of seasonal recharge. A two-dimensional variable density model helped validate this conceptual model of coastal groundwater discharge by showing that fluctuations in groundwater salinity in a coastal aquifer can be driven by a seasonal coastal boundary condition in spite of seasonal recharge/discharge dynamics. Because seasonal variations in sea level and coastal wetlands are ubiquitous throughout the world, these findings have important implications for monitoring and management of coastal groundwater-dependent ecosystems.

  19. Interannaul variations of the vertical and their possible influence on the star catalogs derived from ground-based astrometric observations

    NASA Astrophysics Data System (ADS)

    Li, Z. X.

    The efforts at Shanghai Observatory since 1991, in response to the Resolution of IAU Comm.19: "Applications of optical astrometry time and latitude programs", is described in the paper, especially the studies concerned with the interannual variations of the vertical and their influence on the astronomical studies. It is clear now that there is a component of the order 0.01 - 0.02" on an interannual time scale in latitude residuals which is correlated with geophysical phenomena on the Earth. A recent study has confirmed that the component discovered is actually the variation of the vertical, related to ground-based observation in astronomy. So, it should be emphasized now that the variation of the vertical is significant enough to be considered in astronomy from now on. Its influence on the past studies, including the star catalogs already published and the ERP before 1980 when optical astrometry observations were still used, should be studied in the future. In comparing the HIPPARCOS catalog with those derived by the past observations, we should keep in mind the existence of this error in an astrometric observation and its influence on the star catalogs and other results derived from ground-based astrometric observations.

  20. Influence of respirometry methods on intraspecific variation in standard metabolic rates in newts.

    PubMed

    Kristín, Peter; Gvoždík, Lumír

    2012-09-01

    Standard metabolic rate (SMR) is both a highly informative and variable trait. Variation in SMR stems not only from diverse intrinsic and extrinsic factors, but also from the use of diverse methods for metabolic measurements. We measured CO(2) production (VCO(2)) and oxygen consumption rates (VO(2)) using two flow-through respirometry modes, continuous and intermittent (stop-flow), to evaluate their potential contribution to SMR variation in Alpine newts, Ichthyosaura alpestris. Both respirometry modes yielded similar and repeatable VCO(2) values. Although VO(2) was highly repeatable, continuous respirometry produced lower VO(2) than the intermittent method. During intermittent measurements, the total number of activity bouts was higher than during continuous respirometry trials. Statistical correction for disparate activity levels minimized variation in oxygen consumption between respirometry modes. We conclude that use of either method of flow-through respirometry, if properly applied, introduced less noise to SMR estimates than a variation in activity levels.

  1. Variations in the Free Chlorine Content of the Stratosphere (1991-1997): Anthropogenic an Volcanic Influences

    NASA Technical Reports Server (NTRS)

    Froidevaux, L.; Waters, J.; Read, W.; Connell, P.; Kinnison, D.; Russell, J.

    1999-01-01

    Remote sensing of chlorine monoxide (CIO) by the Microwave Limb Sounder (MLS) experiment aboard the Upper Atmosphere Research Satellite (UARS) has provided global measurements of variations in stratospheric free chlorine (for 1991 to 1997).

  2. Solar activity influence on climatic variations of stratosphere and mesosphere in mid-latitudes

    NASA Technical Reports Server (NTRS)

    Taubenheim, J.; Entzian, G.; Voncossart, G.

    1989-01-01

    The direct modulation of temperature of the mid-latitude mesosphere by the solar-cycle EUV variation, which leads to greater heat input at higher solar activity, is well established. Middle atmosphere temperature modulation by the solar cycle is independently confirmed by the variation of reflection heights of low frequency radio waves in the lower ionosphere, which are regularly monitored over about 30 years. As explained elsewhere in detail, these reflection heights depend on the geometric altitude of a certain isobaric surface (near 80 k), and on the solar ionizing Lyman-alpha radiation flux. Knowing the solar cycle variation of Lyman-alpha how much the measured reflection heights would be lowered with the transition from solar minimum to maximum can be calculated, if the vertical baric structure of the neutral atmosphere would remain unchanged. An discrepancy between expected and observed height change must be explained by an uplifting of the isobaric level from solar minimum to maximum, caused by the temperature rise in the mesosphere. By integrating the solar cycle temperature changes over the height region of the middle atmosphere, and assuming that the lower boundary (tropopause) has no solar cycle variation, the magnitude of this uplifting can be estimated. It is given for the Lidar-derived and for the rocket-measured temperature variations. Comparison suggests that the real amplitude of the solar cycle temperature variation in the mesosphere is underestimated when using the rocket data, but probably overestimated with the Lidar data.

  3. Influence of glucocorticoids on a time-of-day-dependent variation in intradermal reactivity to histamine in dogs.

    PubMed

    Goto, Shun; Shimizu, Sunao; Watanabe, Miwa; Osada, Hironari; Sasaki, Kazuaki; Shimoda, Minoru; Nagai, Makoto; Shirai, Junsuke; Itoh, Hiroshi; Ohmori, Keitaro

    2016-08-01

    The objectives of this study were to determine daily variation in intradermal reactivity to histamine in dogs and to evaluate a potential influence of glucocorticoids on reactivity. Wheal sizes formed after intradermal injections of histamine were measured every 6 h during a single 24 h period in six healthy dogs. To determine whether glucocorticoids were implicated in daily variation, intradermal reactivity to histamine was evaluated at 9:00 h and at 21:00 h during a single day in dogs that received oral prednisolone (a synthetic glucocorticoid) or oral trilostane (an inhibitor of endogenous glucocorticoid synthesis). Finally, the time required for the histamine reaction to diminish after an intravenous injection of hydrocortisone was also assessed. A significant time-of-day-dependent variation in intradermal reactivity to histamine was detected in dogs, with a larger wheal size observed at 9:00 h than at 21:00 h. Administration of prednisolone or trilostane disrupted this variation. Intradermal reactivity to histamine was significantly reduced 6 h after an intravenous injection of hydrocortisone. These results suggest that glucocorticoid secretion from the adrenal glands could be involved in the regulation of daily variation in histamine-mediated reactions in dogs. PMID:27387732

  4. The meaning of "physical fitness".

    PubMed

    Hopkins, W G; Walker, N P

    1988-11-01

    The understanding of the term "physical fitness" was determined for a randomly selected sample (n = 94) of a population using a self-administered mailed questionnaire. Subjects were asked to state and give a reason for their perceived level of physical fitness, to state their perceived performance level in a number of physical fitness tests (muscular strength, daily physical work capacity, fatness, level of regular physical exercise, exercise speed, and body flexibility), and to rate how well these tests measure physical fitness. The reason most frequently stated for perceived level of physical fitness was the level of habitual physical activity (43%); significantly less frequently (P less than 0.01-0.0001) cited were reasons related to health (23%), physical performance (12%), and obesity (3%). The variation in perceived level of physical fitness was best explained by the variation in imagined regular exercise and fatness (r2 = 0.66, P less than 0.0001) with no significant additional contribution from imagined performance in remaining fitness tests. The measurement of regular exercise was most favored as a test of physical fitness. These results, taken together with evidence of the physical and psychological health benefits of regular exercise, imply that the most appropriate measure of physical fitness for the average person is an assessment of the habitual physical activity level.

  5. Understanding the relative influence of climatic variations and agricultural management practices on crop yields at the US county level

    NASA Astrophysics Data System (ADS)

    Leng, G.; Zhang, X.; Huang, M.; Yang, Q.; Rafique, R.; Asrar, G.; Leung, L. R.

    2015-12-01

    Crop yields are largely determined by climate variations and agricultural management practices, such as irrigation, fertilization and residue management. Understanding the role of these factors in regulating crop yield variations is not only important for improved crop yield production, but also equally valuable for future crop yield prediction and food security assessments. Recently, the Community Land Model (CLM) has been augmented and evaluated for simulating corn, soybean and cereals at coarse aerial resolutions of 2 degrees (2000x2000 km). To better understand the underlying mechanisms controlling yield variations, we implemented and validated the agricultural version of CLM (CLM-crop) at a 0.125 degree resolution over the Conterminous United States (CONUS). We conducted a suite of numerical experiments to untangle the relative influence of climatic variations (temperature, precipitation, and radiation) and agricultural management practices on yield variations for the past 30 years at the US county level. Preliminary results show that the model with default parameter settings captures well the temporal variations in crop yields, as compared with the actual yield reported by the US Department of Agriculture (USDA). However, the magnitude of simulated crop yields is substantially higher, especially in the Mid-western US. We find that improved characterization of fertilizers and irrigation practices is key to model performance. Retrospectively (1979-2012), crop yields are more sensitive to changes in climate factors (such as temperature) than to changes in crop management practices. The results of this study advances understanding of the dominant factors in regulating the crop yield variations at the county level, which is essential for credible prediction of crop yields in a changing climate, under different agricultural management practices.

  6. Influence of topography on the temperature variation around the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Kubokawa, H.; Masaki, S.; Fujiwara, M.; Suzuki, J.

    2015-12-01

    Temperature variations in the Tropical Tropopause Layer (TTL) are an important factor for dehydration in the UTLS region. It is known that Kelvin waves induce large temperature variations in the TTL. We investigated the temperature variations in the TTL using both numerical data produced by the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) and various observational data including satellite data (the Constellation Observing System for Meteorology, Ionosphere, and Climate; COSMIC), the reanalysis data of different resolution (ERA-40-interim, NCEP-CFSR, MERRA, YOTC-ECMWF), and radiosonde data for the Cooperative Indian Ocean experiment on intra-seasonal variability in the Year 2011 (CINDY). We found that all the data shows that the temperature variations become larger over the mountainous regions of the Indonesian maritime continent than over the oceanic regions and that the large temperature variations are associated with Kelvin waves. As, the horizontal resolution of the reanalysis becomes higher, the standard deviations of the TTL temperature near the mountains became larger. When Kelvin waves passed over the Indonesian maritime continent, the amplitude of temperature becomes about 2 K larger over the mountainous regions. The power spectrum for the periods between 7 days and 12 days was larger over the mountainous regions compared with that over the ocean. The sensitivity study using the stretch-NICAM shows that the height of mountains clearly affect the amplitude of temperature near the TTL.

  7. Influence of geometry variations on the gravitational focusing of timelike geodesic congruences

    NASA Astrophysics Data System (ADS)

    Seriu, Masafumi

    2015-10-01

    We derive a set of equations describing the linear response of the convergence properties of a geodesic congruence to arbitrary geometry variations. It is a combination of equations describing the deviations from the standard Raychaudhuri-type equations due to the geodesic shifts and an equation describing the geodesic shifts due to the geometry variations. In this framework, the geometry variations, which can be chosen arbitrarily, serve as probes to investigate the gravitational contraction processes from various angles. We apply the obtained framework to the case of conformal geometry variations, characterized by an arbitrary function f (x ), and see that the formulas get simplified to a great extent. We investigate the response of the convergence properties of geodesics in the latest phase of gravitational contractions by restricting the class of conformal geometry variations to the one satisfying the strong energy condition. We then find out that in the final stage, f and D .D f control the overall contraction behavior and that the contraction rate gets larger when f is negative and |f | is so large as to overwhelm |D .D f |. (Here D .D is the Laplacian operator on the spatial hypersurfaces orthogonal to the geodesic congruence in concern.) To get more concrete insights, we also apply the framework to the time-reversed Friedmann-Robertson-Walker model as the simplest case of the singularity formations.

  8. Temporal and spatial variation in Hg accumulation in zebra mussels (Dreissena polymorpha): possible influences of DOC and diet.

    PubMed

    Kraemer, Lisa D; Evans, Douglas; Dillon, Peter J

    2013-05-01

    Zebra mussels (Dreissena polymorpha) are filter feeders located near the base of the foodweb and these animals are able to utilize a variety of carbon sources that may also vary seasonally. We conducted both a spatial and a temporal study in order to test the hypotheses: (1) dissolved organic carbon (DOC) concentrations influence Hg accumulation in zebra mussels sampled from a series of lakes and (2) seasonal variations in diet influence Hg accumulation. In the spatial study, we found a significant negative relationship between Hg concentrations and DOC concentrations, suggesting an influence of DOC on Hg bioaccumulation. In the temporal study, we used stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) as ecological tools to provide a temporally integrated description of the feeding ecology of zebra mussels. Both δ(15)N and δ(13)C varied seasonally in a similar manner: more depleted values occurred in the summer and more enriched values occurred in the fall. Mercury concentrations also varied significantly over the year, with highest concentrations occurring in the summer, followed by a progressive decrease in concentrations into the fall. The C/N ratio of zebra mussels also varied significantly over the year with the lowest values occurring mid-summer and then values increased in the fall and winter, suggesting that there was significant variation in lipid stores. These results indicate that in addition to any effect of seasonal dietary changes, seasonal variation in energy stores also appeared to be related to Hg levels in the zebra mussels. Collectively results from this study suggest that DOC concentrations, seasonal variation in diet and seasonal depletion of energy stores are all important variables to consider when understanding Hg accumulation in zebra mussels. PMID:23433835

  9. Temporal and spatial variation in Hg accumulation in zebra mussels (Dreissena polymorpha): possible influences of DOC and diet.

    PubMed

    Kraemer, Lisa D; Evans, Douglas; Dillon, Peter J

    2013-05-01

    Zebra mussels (Dreissena polymorpha) are filter feeders located near the base of the foodweb and these animals are able to utilize a variety of carbon sources that may also vary seasonally. We conducted both a spatial and a temporal study in order to test the hypotheses: (1) dissolved organic carbon (DOC) concentrations influence Hg accumulation in zebra mussels sampled from a series of lakes and (2) seasonal variations in diet influence Hg accumulation. In the spatial study, we found a significant negative relationship between Hg concentrations and DOC concentrations, suggesting an influence of DOC on Hg bioaccumulation. In the temporal study, we used stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) as ecological tools to provide a temporally integrated description of the feeding ecology of zebra mussels. Both δ(15)N and δ(13)C varied seasonally in a similar manner: more depleted values occurred in the summer and more enriched values occurred in the fall. Mercury concentrations also varied significantly over the year, with highest concentrations occurring in the summer, followed by a progressive decrease in concentrations into the fall. The C/N ratio of zebra mussels also varied significantly over the year with the lowest values occurring mid-summer and then values increased in the fall and winter, suggesting that there was significant variation in lipid stores. These results indicate that in addition to any effect of seasonal dietary changes, seasonal variation in energy stores also appeared to be related to Hg levels in the zebra mussels. Collectively results from this study suggest that DOC concentrations, seasonal variation in diet and seasonal depletion of energy stores are all important variables to consider when understanding Hg accumulation in zebra mussels.

  10. Exercise Prescription for Physical Fitness.

    ERIC Educational Resources Information Center

    Pollock, Michael L.; And Others

    1995-01-01

    Examines current guidelines for physical fitness, noting issues that may influence the updating of the American College of Sports Medicine exercise statement. Differences between exercise prescription for fitness and physical activity for health are discussed, noting the importance of designing individualized programs with appropriate levels of…

  11. Subtle variation in ambient room temperature influences the expression of social cognition.

    PubMed

    Vigil, Jacob M; Swartz, Tyler J; Rowell, Lauren N

    2013-10-01

    Social signaling models predict that subtle variation in climatic temperature induces systematic changes in expressed cognition. An experiment showed that perceived room temperature was associated with variability in self-descriptions, social reactions of others, and desiring differing types of social networks. The findings reflect the tendency to inflate capacity demonstrations in warmer climates as a result of the social networking opportunities they enable.

  12. Brain modularity across the theropod-bird transition: testing the influence of flight on neuroanatomical variation.

    PubMed

    Balanoff, Amy M; Smaers, Jeroen B; Turner, Alan H

    2016-08-01

    Living birds constitute the only vertebrate group whose brain volume relative to body size approaches the uniquely expanded values expressed by mammals. The broad suite of complex behaviors exhibited by crown-group birds, including sociality, vocal learning, parental care, and flying, suggests the origins of their encephalization was likely driven by a mosaic of selective pressures. If true, the historical pattern of brain expansion may be more complex than either a gradual expansion, as proposed by early studies of the avian brain, or a sudden expansion correlating with the appearance of flight. The origins of modern avian neuroanatomy are obscured by the more than 100 million years of evolution along their phylogenetic stem (from the origin of the modern radiation in the Middle Jurassic to the split from crocodile-line archosaurs). Here we use phylogenetic comparative approaches to explore which evolutionary scenarios best explain variation in measured volumes of digitally partitioned endocasts of modern birds and their non-avian ancestors. Our analyses suggest that variation in the relative volumes of the endocranium and cerebrum explain most of the structural variation in this lineage. Generalized multi-regime Ornstein-Uhlenbeck (OU) models suggest that powered flight does not appear to be a driver of observed variation, reinforcing the hypothesis that the deep history of the avian brain is complex, with nuances still to be discovered. PMID:26538376

  13. Influence of Analogy Instruction for Pitch Variation on Perceptual Ratings of Other Speech Parameters

    ERIC Educational Resources Information Center

    Tse, Andy C. Y.; Wong, Andus W-K.; Ma, Estella P-M.; Whitehill, Tara L.; Masters, Rich S. W.

    2013-01-01

    Purpose: "Analogy" is the similarity of different concepts on which a comparison can be based. Recently, an analogy of "waves at sea" was shown to be effective in modulating fundamental frequency (F[subscript 0]) variation. Perceptions of intonation were not examined, as the primary aim of the work was to determine whether…

  14. Influence of Stuttering Variation on Talker Group Classification in Preschool Children: Preliminary Findings

    ERIC Educational Resources Information Center

    Johnson, Kia N.; Karrass, Jan; Conture, Edward G.; Walden, Tedra

    2009-01-01

    The purpose of this study was to investigate whether variations in disfluencies of young children who do (CWS) and do not stutter (CWNS) significantly change their talker group classification or diagnosis from stutterer to nonstutterer, and vice versa. Participants consisted of seventeen 3- to 5-year-old CWS and nine 3- to 5-year-old CWNS, with no…

  15. Solar variations and their influence on trends in upper stratospheric ozone and temperature

    SciTech Connect

    Wuebbles, D.J.; Kinnison, D.E. ); Lean, J.L. . E.O. Hulburt Center for Space Research)

    1990-10-01

    Over the past decade, knowledge of the magnitude and temporal structure of the variations in the sun's ultraviolet irradiance has increased steadily. A number of theoretical modeling studies have shown that changes in the solar ultraviolet flux during the 11-year solar cycle can have a significant effect on stratospheric ozone concentrations. With the exception of Brasseur et al., who examined a very broad range of solar flux variations, all of these studies assumed much larger changes in the ultraviolet flux than measurements now indicate. These studies either calculated the steady-state effect at solar maximum and solar minimum or assumed sinusoidal variations in the solar flux changes with time. It is now possible to narrow the uncertainty range of the expected effects on upper stratospheric ozone and temperature resulting from the 11-year solar cycle. A more accurate representation of the solar flux changes with time is used in this analysis, as compared to previous published studies. This study also evaluates the relative roles of solar flux variations and increasing concentrations of long-lived trace gases in determining the observed trends in upper stratospheric ozone and temperature. The LLNL two-dimensional chemical-radiative-transport model of the global atmosphere is used to evaluate the combined effects on the stratosphere from changes in solar ultraviolet irradiances and trace gas concentrations over the last several decades. Derived trends in upper stratospheric ozone concentrations and temperature are then compared with available analyses of ground-based and satellite measurements over this time period.

  16. The influence of sensitisation to pollens and moulds on seasonal variations in asthma attacks

    PubMed Central

    Canova, Cristina; Heinrich, Joachim; Anto, Josep Maria; Leynaert, Benedicte; Smith, Matthew; Kuenzli, Nino; Zock, Jan-Paul; Janson, Christer; Cerveri, Isa; de Marco, Roberto; Toren, Kjell; Gislason, Thorarinn; Nowak, Dennis; Pin, Isabelle; Wjst, Matthias; Manfreda, Jure; Svanes, Cecilie; Crane, Julian; Abramson, Michael; Burr, Michael; Burney, Peter; Jarvis, Deborah

    2013-01-01

    No large study has described the seasonal variation in asthma attacks in population-based asthmatics in whom sensitisation to allergen has been measured. 2637 young adults with asthma living in 15 countries reported the months in which they usually had attacks of asthma and had skin-prick tests performed. Differences in seasonal patterns by sensitisation status were assessed using generalised estimating equations. Most young adults with asthma reported periods of the year when their asthma attacks were more common (range: 47% in Sweden to 86% in Spain). Seasonal variation in asthma was not modified by sensitisation to house dust mite or cat allergens. Asthmatics sensitised to grass, birch and Alternaria allergens had different seasonal patterns to those not sensitised to each allergen, with some geographical variation. In southern Europe, those sensitised to grass allergens were more likely to report attacks occurred in spring or summer than in winter (OR March/April 2.60, 95% CI 1.70–3.97; OR May/June 4.43, 95% CI 2.34–8.39) and smaller later peaks were observed in northern Europe (OR May/June 1.25, 95% CI 0.60–2.64; OR July/August 1.66, 95% CI 0.89–3.10). Asthmatics reporting hay fever but who were not sensitised to grass showed no seasonal variations. Seasonal variations in asthma attacks in young adults are common and are different depending on sensitisation to outdoor, but not indoor, allergens. PMID:23471350

  17. Friendship networks and achievement goals: an examination of selection and influence processes and variations by gender.

    PubMed

    Shin, Huiyoung; Ryan, Allison M

    2014-09-01

    Interactions with friends are a salient part of students' experience at school. Thus, friends are likely to be an important source of influence on achievement goals. This study investigated processes within early adolescent friendships (selection and influence) with regard to achievement goals (mastery, performance-approach, and performance-avoidance goals) among sixth graders (N = 587, 50% girls at wave 1, N = 576, 52% girls at wave 2) followed from fall to spring within one academic year. Students' gender was examined as a moderator in these processes. Longitudinal social network analysis found that friends were similar to each other in mastery goals and that this similarity was due to both selection and influence effects. Influence but not selection effects were found for performance-approach goals. Influence effects for performance-approach goals were stronger for boys compared to girls in the classroom. Neither selection, nor influence, effects were found in relation to performance-avoidance goals. However, the higher a student was in performance-avoidance goals, the less likely they were to be named as a friend by classmates. Implications for early adolescents' classroom adjustment are discussed.

  18. Influence of Sub-Daily Variation on Multi-Fractal Detrended Fluctuation Analysis of Wind Speed Time Series.

    PubMed

    Wang, Xianxun; Mei, Yadong; Li, Weinan; Kong, Yanjun; Cong, Xiangyu

    2016-01-01

    Using multi-fractal detrended fluctuation analysis (MF-DFA), the scaling features of wind speed time series (WSTS) could be explored. In this paper, we discuss the influence of sub-daily variation, which is a natural feature of wind, in MF-DFA of WSTS. First, the choice of the lower bound of the segment length, a significant parameter of MF-DFA, was studied. The results of expanding the lower bound into sub-daily scope shows that an abrupt declination and discrepancy of scaling exponents is caused by the inability to keep the whole diel process of wind in one single segment. Additionally, the specific value, which is effected by the sub-daily feature of local meteo-climatic, might be different. Second, the intra-day temporal order of wind was shuffled to determine the impact of diel variation on scaling exponents of MF-DFA. The results illustrate that disregarding diel variation leads to errors in scaling. We propose that during the MF-DFA of WSTS, the segment length should be longer than 1 day and the diel variation of wind should be maintained to avoid abnormal phenomena and discrepancy in scaling exponents. PMID:26741491

  19. Influence of Sub-Daily Variation on Multi-Fractal Detrended Fluctuation Analysis of Wind Speed Time Series

    PubMed Central

    Li, Weinan; Kong, Yanjun; Cong, Xiangyu

    2016-01-01

    Using multi-fractal detrended fluctuation analysis (MF-DFA), the scaling features of wind speed time series (WSTS) could be explored. In this paper, we discuss the influence of sub-daily variation, which is a natural feature of wind, in MF-DFA of WSTS. First, the choice of the lower bound of the segment length, a significant parameter of MF-DFA, was studied. The results of expanding the lower bound into sub-daily scope shows that an abrupt declination and discrepancy of scaling exponents is caused by the inability to keep the whole diel process of wind in one single segment. Additionally, the specific value, which is effected by the sub-daily feature of local meteo-climatic, might be different. Second, the intra-day temporal order of wind was shuffled to determine the impact of diel variation on scaling exponents of MF-DFA. The results illustrate that disregarding diel variation leads to errors in scaling. We propose that during the MF-DFA of WSTS, the segment length should be longer than 1 day and the diel variation of wind should be maintained to avoid abnormal phenomena and discrepancy in scaling exponents. PMID:26741491

  20. Influence of Sub-Daily Variation on Multi-Fractal Detrended Fluctuation Analysis of Wind Speed Time Series.

    PubMed

    Wang, Xianxun; Mei, Yadong; Li, Weinan; Kong, Yanjun; Cong, Xiangyu

    2016-01-01

    Using multi-fractal detrended fluctuation analysis (MF-DFA), the scaling features of wind speed time series (WSTS) could be explored. In this paper, we discuss the influence of sub-daily variation, which is a natural feature of wind, in MF-DFA of WSTS. First, the choice of the lower bound of the segment length, a significant parameter of MF-DFA, was studied. The results of expanding the lower bound into sub-daily scope shows that an abrupt declination and discrepancy of scaling exponents is caused by the inability to keep the whole diel process of wind in one single segment. Additionally, the specific value, which is effected by the sub-daily feature of local meteo-climatic, might be different. Second, the intra-day temporal order of wind was shuffled to determine the impact of diel variation on scaling exponents of MF-DFA. The results illustrate that disregarding diel variation leads to errors in scaling. We propose that during the MF-DFA of WSTS, the segment length should be longer than 1 day and the diel variation of wind should be maintained to avoid abnormal phenomena and discrepancy in scaling exponents.

  1. Exploring Neighborhood Influences on Small-Area Variations in Intimate Partner Violence Risk: A Bayesian Random-Effects Modeling Approach

    PubMed Central

    Gracia, Enrique; López-Quílez, Antonio; Marco, Miriam; Lladosa, Silvia; Lila, Marisol

    2014-01-01

    This paper uses spatial data of cases of intimate partner violence against women (IPVAW) to examine neighborhood-level influences on small-area variations in IPVAW risk in a police district of the city of Valencia (Spain). To analyze area variations in IPVAW risk and its association with neighborhood-level explanatory variables we use a Bayesian spatial random-effects modeling approach, as well as disease mapping methods to represent risk probabilities in each area. Analyses show that IPVAW cases are more likely in areas of high immigrant concentration, high public disorder and crime, and high physical disorder. Results also show a spatial component indicating remaining variability attributable to spatially structured random effects. Bayesian spatial modeling offers a new perspective to identify IPVAW high and low risk areas, and provides a new avenue for the design of better-informed prevention and intervention strategies. PMID:24413701

  2. The Influence of Social Class on Academic Outcomes: A Structural Equation Model Examining the Relationships between Student Dependency Style, Student-Academic Environment Fit, and Satisfaction on Academic Outcomes

    ERIC Educational Resources Information Center

    Nadler, Dustin R.

    2013-01-01

    The purpose of this study was to investigate the relationship between college students' social class and their academic outcomes. A structural equation model was proposed, hypothesizing that a student's socioeconomic status (SES) is related to their motives for attending college, thus influencing their perception of fit at the university, their…

  3. The influence of weather and lemmings on spatiotemporal variation in the abundance of multiple avian guilds in the arctic.

    PubMed

    Robinson, Barry G; Franke, Alastair; Derocher, Andrew E

    2014-01-01

    Climate change is occurring more rapidly in the Arctic than other places in the world, which is likely to alter the distribution and abundance of migratory birds breeding there. A warming climate can provide benefits to birds by decreasing spring snow cover, but increases in the frequency of summer rainstorms, another product of climate change, may reduce foraging opportunities for insectivorous birds. Cyclic lemming populations in the Arctic also influence bird abundance because Arctic foxes begin consuming bird eggs when lemmings decline. The complex interaction between summer temperature, precipitation, and the lemming cycle hinder our ability to predict how Arctic-breeding birds will respond to climate change. The main objective of this study was to investigate the relationship between annual variation in weather, spring snow cover, lemming abundance and spatiotemporal variation in the abundance of multiple avian guilds in a tundra ecosystem in central Nunavut, Canada: songbirds, shorebirds, gulls, loons, and geese. We spatially stratified our study area based on vegetation productivity, terrain ruggedness, and freshwater abundance, and conducted distance sampling to estimate strata-specific densities of each guild during the summers of 2010-2012. We also monitored temperature, rainfall, spring snow cover, and lemming abundance each year. Spatial variation in bird abundance matched what was expected based on previous ecological knowledge, but weather and lemming abundance also significantly influenced the abundance of some guilds. In particular, songbirds were less abundant during the cool, wet summer with moderate snow cover, and shorebirds and gulls declined with lemming abundance. The abundance of geese did not vary over time, possibly because benefits created by moderate spring snow cover were offset by increased fox predation when lemmings were scarce. Our study provides an example of a simple way to monitor the correlation between weather, spring snow

  4. The Influence of Weather and Lemmings on Spatiotemporal Variation in the Abundance of Multiple Avian Guilds in the Arctic

    PubMed Central

    Robinson, Barry G.; Franke, Alastair; Derocher, Andrew E.

    2014-01-01

    Climate change is occurring more rapidly in the Arctic than other places in the world, which is likely to alter the distribution and abundance of migratory birds breeding there. A warming climate can provide benefits to birds by decreasing spring snow cover, but increases in the frequency of summer rainstorms, another product of climate change, may reduce foraging opportunities for insectivorous birds. Cyclic lemming populations in the Arctic also influence bird abundance because Arctic foxes begin consuming bird eggs when lemmings decline. The complex interaction between summer temperature, precipitation, and the lemming cycle hinder our ability to predict how Arctic-breeding birds will respond to climate change. The main objective of this study was to investigate the relationship between annual variation in weather, spring snow cover, lemming abundance and spatiotemporal variation in the abundance of multiple avian guilds in a tundra ecosystem in central Nunavut, Canada: songbirds, shorebirds, gulls, loons, and geese. We spatially stratified our study area based on vegetation productivity, terrain ruggedness, and freshwater abundance, and conducted distance sampling to estimate strata-specific densities of each guild during the summers of 2010–2012. We also monitored temperature, rainfall, spring snow cover, and lemming abundance each year. Spatial variation in bird abundance matched what was expected based on previous ecological knowledge, but weather and lemming abundance also significantly influenced the abundance of some guilds. In particular, songbirds were less abundant during the cool, wet summer with moderate snow cover, and shorebirds and gulls declined with lemming abundance. The abundance of geese did not vary over time, possibly because benefits created by moderate spring snow cover were offset by increased fox predation when lemmings were scarce. Our study provides an example of a simple way to monitor the correlation between weather, spring snow

  5. The influence of weather and lemmings on spatiotemporal variation in the abundance of multiple avian guilds in the arctic.

    PubMed

    Robinson, Barry G; Franke, Alastair; Derocher, Andrew E

    2014-01-01

    Climate change is occurring more rapidly in the Arctic than other places in the world, which is likely to alter the distribution and abundance of migratory birds breeding there. A warming climate can provide benefits to birds by decreasing spring snow cover, but increases in the frequency of summer rainstorms, another product of climate change, may reduce foraging opportunities for insectivorous birds. Cyclic lemming populations in the Arctic also influence bird abundance because Arctic foxes begin consuming bird eggs when lemmings decline. The complex interaction between summer temperature, precipitation, and the lemming cycle hinder our ability to predict how Arctic-breeding birds will respond to climate change. The main objective of this study was to investigate the relationship between annual variation in weather, spring snow cover, lemming abundance and spatiotemporal variation in the abundance of multiple avian guilds in a tundra ecosystem in central Nunavut, Canada: songbirds, shorebirds, gulls, loons, and geese. We spatially stratified our study area based on vegetation productivity, terrain ruggedness, and freshwater abundance, and conducted distance sampling to estimate strata-specific densities of each guild during the summers of 2010-2012. We also monitored temperature, rainfall, spring snow cover, and lemming abundance each year. Spatial variation in bird abundance matched what was expected based on previous ecological knowledge, but weather and lemming abundance also significantly influenced the abundance of some guilds. In particular, songbirds were less abundant during the cool, wet summer with moderate snow cover, and shorebirds and gulls declined with lemming abundance. The abundance of geese did not vary over time, possibly because benefits created by moderate spring snow cover were offset by increased fox predation when lemmings were scarce. Our study provides an example of a simple way to monitor the correlation between weather, spring snow

  6. The influence of temperature variations on ultrasonic guided waves in anisotropic CFRP plates.

    PubMed

    Putkis, O; Dalton, R P; Croxford, A J

    2015-07-01

    Carbon Fibre Reinforced Polymer (CFRP) materials are lightweight and corrosion-resistant and therefore are increasingly used in aerospace, automotive and construction industries. In Structural Health Monitoring (SHM) applications of CFRP materials, ultrasonic guided waves potentially offer large area inspection or inspection from a remote location. This paper addresses the effect of temperature variation on guided wave propagation in highly anisotropic CFRP materials. Temperature variations cause changes in guided wave velocity that can in turn compromise the baseline subtraction procedures employed by many SHM systems for damage detection. A simple model that describes the dependence of elastic properties of the CFRP plates on temperature is presented in this paper. The model can be used to predict anisotropic velocity changes and baseline subtraction performance under varying thermal conditions. The results produced by the model for unidirectional and 0/90 CFRP plates are compared with experimental measurements. PMID:25812468

  7. On how spatial variations of channel width influence river profile curvature

    NASA Astrophysics Data System (ADS)

    Ferrer-Boix, Carles; Chartrand, Shawn M.; Hassan, Marwan A.; Martín-Vide, Juan P.; Parker, Gary

    2016-06-01

    Longitudinal profiles of alluvial rivers usually exhibit upward-concave curvatures at equilibrium. River profile concavity has been primarily attributed to sediment downstream fining and to streamwise increments of water discharge. Conversely, upward-convex profiles have been typically associated with tectonic and geologic controls and with outlet base-level drops. Equations to describe river profiles at equilibrium developed from mass conservation principles do not consider longitudinal changes in channel width. This study addresses how variations in channel width can also act to control the curvature of longitudinal profiles. We develop a new theoretical framework in which the role on river profiles of downstream variations of channel width, flow discharge, bed roughness, and surface texture are explicitly shown. Unlike classical approaches for river profile evolution, this novel framework identifies physical domains for rivers to develop upward-concave/convex longitudinal profiles depending on channel width and flow discharge gradients flow intensity and surface texture.

  8. The influence of temperature variations on ultrasonic guided waves in anisotropic CFRP plates.

    PubMed

    Putkis, O; Dalton, R P; Croxford, A J

    2015-07-01

    Carbon Fibre Reinforced Polymer (CFRP) materials are lightweight and corrosion-resistant and therefore are increasingly used in aerospace, automotive and construction industries. In Structural Health Monitoring (SHM) applications of CFRP materials, ultrasonic guided waves potentially offer large area inspection or inspection from a remote location. This paper addresses the effect of temperature variation on guided wave propagation in highly anisotropic CFRP materials. Temperature variations cause changes in guided wave velocity that can in turn compromise the baseline subtraction procedures employed by many SHM systems for damage detection. A simple model that describes the dependence of elastic properties of the CFRP plates on temperature is presented in this paper. The model can be used to predict anisotropic velocity changes and baseline subtraction performance under varying thermal conditions. The results produced by the model for unidirectional and 0/90 CFRP plates are compared with experimental measurements.

  9. Influence of paleo-heat flow variations on estimates of exhumation rates

    NASA Astrophysics Data System (ADS)

    von Hagke, Christoph; Luijendijk, Elco

    2016-04-01

    Deriving exhumation estimates from thermochronological data requires assumptions on the paleo-thermal field of the Earth's crust. Existing thermal models take into account heat transfer by diffusion and advection caused by the movement of the crust and erosion as well as changes in geothermal gradient over time caused by changes in structure or thermal properties of the crust, surface temperature and elevation. However, temperature field of mountain belts and basins may vary not only due to tectonic activity or landscape evolution. We present a high-resolution thermochronology data set from the foreland fold-and-thrust belt of the European Alps that shows substantial variation of cooling rates probably caused by hydrothermal flow in the subsurface in the past. Tectonic blocks with uniform exhumation history show variations in cooling of up to 50°C. In addition, changes in cooling between two different fault blocks show opposite trend than expected by models of their tectonic history. The observed historic changes in paleo-geothermal gradients are equal in magnitude to a present-day thermal anomaly caused by the upward flow of warm fluids in the distal part of the foreland basin. The strong variations in geothermal gradients by fluid flow imply that straightforward interpretation of landscape evolution rates using thermochronology is not possible, unless the thermal effects of fluid flow are taken into account. This is of particular importance to studies where the amount of thermochronology data is limited and local hydrothermal anomalies could easily be interpreted as regional exhumation signals. On the other hand, our findings suggest that thermochronology offers new opportunities to constrain magnitude and timing of paleo-heat flow variations in the upper crust.

  10. Environmental enrichment influences brain cytokine variations elicited by social defeat in mice.

    PubMed

    McQuaid, Robyn J; Audet, Marie-Claude; Jacobson-Pick, Shlomit; Anisman, Hymie

    2013-07-01

    Environmental enrichment may protect against some of the adverse behavioural and biological effects of stressors. However, unlike the effects seen in some species, among male mice housed in groups, enrichment may alter social stability, encourage competition and aggression, and thus promote the establishment of a stressful environment. A potent psychosocial stressor such as social defeat in mice promotes brain neurochemical changes as well as pro-inflammatory cytokine variations in the prefrontal cortex (PFC) and hippocampus. The present investigation demonstrated that enrichment in group-housed male mice, even in the relatively nonaggressive, although highly anxious BALB/cByJ strain encouraged the effects of a repeated social defeat stressor experienced 4 weeks later, especially with respect to corticosterone as well as hippocampal corticotropin-releasing hormone (CRH) and interleukin (IL)-6 variations. Moreover, within the hippocampus, enrichment itself was accompanied by modest reductions in the expression of the IL-1β receptor (IL-1r1). Thus, it seems that living in an enriched environment among group-housed male mice might promote a stressful environment that enhances basal hippocampal CRH and cytokine variations and increased vulnerability to further changes upon subsequent exposure to a social stressor.

  11. Variations in CYP78A13 coding region influence grain size and yield in rice.

    PubMed

    Xu, Fan; Fang, Jun; Ou, Shujun; Gao, Shaopei; Zhang, Fengxia; Du, Lin; Xiao, Yunhua; Wang, Hongru; Sun, Xiaohong; Chu, Jinfang; Wang, Guodong; Chu, Chengcai

    2015-04-01

    Grain size is one of the most important determinants of crop yield in cereals. Here, we identified a dominant mutant, big grain2 (bg2-D) from our enhancer-trapping population. Genetic analysis and SiteFinding PCR (polymerase chain reaction) revealed that BG2 encodes a cytochrome P450, OsCYP78A13. Sequence search revealed that CYP78A13 has a paralogue Grain Length 3.2 (GL3.2, LOC_Os03g30420) in rice with distinct expression patterns, analysis of transgenic plants harbouring either CYP78A13 or GL3.2 showed that both can promote grain growth. Sequence polymorphism analysis with 1529 rice varieties showed that the nucleotide diversity at CYP78A13 gene body and the 20 kb flanking region in the indica varieties were markedly higher than those in japonica varieties. Further, comparison of the genomic sequence of CYP78A13 in the japonica cultivar Nipponbare and the indica cultivar 9311 showed that there were three InDels in the promoter region and eight SNPs (single nucleotide polymorphism) in its coding sequence. Detailed examination of the transgenic plants with chimaeric constructs suggested that variation in CYP78A13 coding region is responsible for the variation of grain yield. Taken together, our results suggest that the variations in CYP78A13 in the indica varieties hold potential in rice breeding for application of grain yield improvement.

  12. Seasonal variation of plankton communities influenced by environmental factors in an artificial lake

    NASA Astrophysics Data System (ADS)

    Li, Xuemei; Yu, Yuhe; Zhang, Tanglin; Feng, Weisong; Ao, Hongyi; Yan, Qingyun

    2012-05-01

    We evaluated the seasonal variation in plankton community composition in an artificial lake. We conducted microscopic analysis and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified partial 16S rRNA and 18S rRNA genes to characterize the plankton community. The clustering of unweighted pair group method with arithmetic mean (UPGMA) was then used to investigate the similarity of these plankton communities. DGGE fingerprinting revealed that samples collected at the different sites within a season shared high similarity and were generally grouped together. In contrast, we did not observe any seasonal variation based on microscopic analysis. Redundancy analysis (RDA) of the plankton operational taxonomic units (OTUs) in relation to environmental factors revealed that transparency was negatively correlated with the first axis ( R=-0.931), and temperature and total phosphorus (TP) were positively correlated with the first axis ( R=0.736 and R=0.660, respectively). In conclusion, plankton communities in the artificial lake exhibited significant seasonal variation. Transparency, phosphorus and temperature appear to be the major factors driving the differences in plankton composition.

  13. Influence of Dapagliflozin on Glycemic Variations in Patients with Newly Diagnosed Type 2 Diabetes Mellitus

    PubMed Central

    Li, Feng-fei; Gao, Gu; Li, Qian; Zhu, Hong-hong; Su, Xiao-fei; Wu, Jin-dan

    2016-01-01

    Objectives. To observe changes in blood glycemic variations and oxidative stress level before and after dapagliflozin treatment in patients with newly diagnosed T2DM. Methods. This was a randomized, double-blind, placebo-controlled, phase 3 trial. A total of 28 patients with newly diagnosed T2DM with HbA1c levels of 7.5–10.5% were randomly selected to receive dapagliflozin or placebo treatment for 24 weeks. After baseline data were collected, we analyzed glycemic variations and plasma 8-iso PGF2α level at baseline and at the endpoint. Primary outcome was the changes of mean amplitude glycemic excursion (MAGE) within groups. Results. After 24-week dapagliflozin therapy, our data showed the significant improvement of MAGE with dapagliflozin therapy (P = 0.010). Compared with control group, patients in dapagliflozin group exhibited reduction in 24-hour MBG (P = 0.026) and lower mean plasma glucose concentrations, especially during periods from 2400 to 0200 and 1300 to 1800 (P < 0.05, resp.). In addition, plasma 8-iso PGF2α level was notably decreased in the treatment group compared to the control group (P = 0.034). Conclusions. In conclusion, this study shows the ability of dapagliflozin to improve glycemic variations and associate with reduction of oxidative stress in patients with T2DM, which may benefit the cardiovascular system. PMID:27738639

  14. Variations of deep soil moisture under different vegetation types and influencing factors in a watershed of the Loess Plateau, China

    NASA Astrophysics Data System (ADS)

    Fang, Xuening; Zhao, Wenwu; Wang, Lixin; Feng, Qiang; Ding, Jingyi; Liu, Yuanxin; Zhang, Xiao

    2016-08-01

    Soil moisture in deep soil layers is a relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the variations in deep soil moisture and its influencing factors at a moderate watershed scale is important to ensure the sustainability of vegetation restoration efforts. In this study, we focus on analyzing the variations and factors that influence the deep soil moisture (DSM) in 80-500 cm soil layers based on a soil moisture survey of the Ansai watershed in Yan'an in Shanxi Province. Our results can be divided into four main findings. (1) At the watershed scale, higher variations in the DSM occurred at 120-140 and 480-500 cm in the vertical direction. At the comparable depths, the variation in the DSM under native vegetation was much lower than that in human-managed vegetation and introduced vegetation. (2) The DSM in native vegetation and human-managed vegetation was significantly higher than that in introduced vegetation, and different degrees of soil desiccation occurred under all the introduced vegetation types. Caragana korshinskii and black locust caused the most serious desiccation. (3) Taking the DSM conditions of native vegetation as a reference, the DSM in this watershed could be divided into three layers: (i) a rainfall transpiration layer (80-220 cm); (ii) a transition layer (220-400 cm); and (iii) a stable layer (400-500 cm). (4) The factors influencing DSM at the watershed scale varied with vegetation types. The main local controls of the DSM variations were the soil particle composition and mean annual rainfall; human agricultural management measures can alter the soil bulk density, which contributes to higher DSM in farmland and apple orchards. The plant growth conditions, planting density, and litter water holding capacity of introduced vegetation showed significant relationships with the DSM. The results of this study are of practical significance for vegetation restoration strategies, especially

  15. A three-dimensional finite element analysis of a passive and friction fit implant abutment interface and the influence of occlusal table dimension on the stress distribution pattern on the implant and surrounding bone

    PubMed Central

    Sarfaraz, Hasan; Paulose, Anoopa; Shenoy, K. Kamalakanth; Hussain, Akhter

    2015-01-01

    Aims: The aim of the study was to evaluate the stress distribution pattern in the implant and the surrounding bone for a passive and a friction fit implant abutment interface and to analyze the influence of occlusal table dimension on the stress generated. Materials and Methods: CAD models of two different types of implant abutment connections, the passive fit or the slip-fit represented by the Nobel Replace Tri-lobe connection and the friction fit or active fit represented by the Nobel active conical connection were made. The stress distribution pattern was studied at different occlusal dimension. Six models were constructed in PRO-ENGINEER 05 of the two implant abutment connection for three different occlusal dimensions each. The implant and abutment complex was placed in cortical and cancellous bone modeled using a computed tomography scan. This complex was subjected to a force of 100 N in the axial and oblique direction. The amount of stress and the pattern of stress generated were recorded on a color scale using ANSYS 13 software. Results: The results showed that overall maximum Von Misses stress on the bone is significantly less for friction fit than the passive fit in any loading conditions stresses on the implant were significantly higher for the friction fit than the passive fit. The narrow occlusal table models generated the least amount of stress on the implant abutment interface. Conclusion: It can thus be concluded that the conical connection distributes more stress to the implant body and dissipates less stress to the surrounding bone. A narrow occlusal table considerably reduces the occlusal overload. PMID:26929518

  16. Influence of host age on critical fitness parameters of Spathius galinae (Hymenoptera: Braconidae), a new parasitoid of the emerald ash borer (Coleoptera: Buprestidae).

    PubMed

    Watt, Timothy J; Duan, Jian J

    2014-08-01

    Spathius galinae Belokobylskij and Strazenac (Hymenoptera: Braconidae) is a recently discovered gregarious idiobiont larval ectoparasitoid currently being evaluated for biological control against the invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) in the United States. To aid in the development of laboratory rearing protocols, we assessed the influence of various emerald ash borer stages on critical fitness parameters of S. galinae. We exposed gravid S. galinae females to emerald ash borer host larvae of various ages (3.5, 5, 7, and 10 wk post egg oviposition) that were reared naturally in tropical (evergreen) ash (Fraxinus uhdei (Wenzig) Lingelsh) logs, or to field-collected, late-stage emerald ash borers (nonfeeding J-shaped larvae termed "J-larvae," prepupae, and pupae) that were artificially inserted into green ash logs. When exposed to larvae in tropical ash logs, S. galinae attacked 5 and 7 wk hosts more frequently (68-76%) than 3.5 wk (23%) and 10 wk (12%) hosts. Subsample dissections of the these logs revealed that 3.5, 5, 7 and 10 wk host logs contained mostly second, third, fourth, and J-larvae, respectively, that had already bored into the sapwood for diapause. No J-larvae were attacked by S. galinae when naturally reared in tropical ash logs. When parasitized by S. galinae, 7 and 10 wk hosts produced the largest broods (approximately 6.7 offspring per parasitized host), and the progenies that emerged from these logs had larger anatomical measurements and more female-biased sex ratios. When exposed to emerald ash borer J-larvae, prepupae, or pupae artificially inserted into green ash logs, S. galinae attacked 53% ofJ-larvae, but did not attack any prepupae or pupae. We conclude that large (fourth instar) emerald ash borer larvae should be used to rear S. galinae. PMID:25195418

  17. Influence of host age on critical fitness parameters of Spathius galinae (Hymenoptera: Braconidae), a new parasitoid of the emerald ash borer (Coleoptera: Buprestidae).

    PubMed

    Watt, Timothy J; Duan, Jian J

    2014-08-01

    Spathius galinae Belokobylskij and Strazenac (Hymenoptera: Braconidae) is a recently discovered gregarious idiobiont larval ectoparasitoid currently being evaluated for biological control against the invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) in the United States. To aid in the development of laboratory rearing protocols, we assessed the influence of various emerald ash borer stages on critical fitness parameters of S. galinae. We exposed gravid S. galinae females to emerald ash borer host larvae of various ages (3.5, 5, 7, and 10 wk post egg oviposition) that were reared naturally in tropical (evergreen) ash (Fraxinus uhdei (Wenzig) Lingelsh) logs, or to field-collected, late-stage emerald ash borers (nonfeeding J-shaped larvae termed "J-larvae," prepupae, and pupae) that were artificially inserted into green ash logs. When exposed to larvae in tropical ash logs, S. galinae attacked 5 and 7 wk hosts more frequently (68-76%) than 3.5 wk (23%) and 10 wk (12%) hosts. Subsample dissections of the these logs revealed that 3.5, 5, 7 and 10 wk host logs contained mostly second, third, fourth, and J-larvae, respectively, that had already bored into the sapwood for diapause. No J-larvae were attacked by S. galinae when naturally reared in tropical ash logs. When parasitized by S. galinae, 7 and 10 wk hosts produced the largest broods (approximately 6.7 offspring per parasitized host), and the progenies that emerged from these logs had larger anatomical measurements and more female-biased sex ratios. When exposed to emerald ash borer J-larvae, prepupae, or pupae artificially inserted into green ash logs, S. galinae attacked 53% ofJ-larvae, but did not attack any prepupae or pupae. We conclude that large (fourth instar) emerald ash borer larvae should be used to rear S. galinae.

  18. Long-term influence of normal variation in neonatal characteristics on human brain development

    PubMed Central

    Walhovd, Kristine B.; Fjell, Anders M.; Brown, Timothy T.; Kuperman, Joshua M.; Chung, Yoonho; Hagler, Donald J.; Roddey, J. Cooper; Erhart, Matthew; McCabe, Connor; Akshoomoff, Natacha; Amaral, David G.; Bloss, Cinnamon S.; Libiger, Ondrej; Schork, Nicholas J.; Darst, Burcu F.; Casey, B. J.; Chang, Linda; Ernst, Thomas M.; Frazier, Jean; Gruen, Jeffrey R.; Kaufmann, Walter E.; Murray, Sarah S.; van Zijl, Peter; Mostofsky, Stewart; Dale, Anders M.; Jernigan, Terry L.; McCabe, Connor; Chang, Linda; Akshoomoff, Natacha; Newman, Erik; Dale, Anders M.; Ernst, Thomas; Dale, Anders M.; Van Zijl, Peter; Kuperman, Joshua; Murray, Sarah; Bloss, Cinnamon; Schork, Nicholas J.; Appelbaum, Mark; Gamst, Anthony; Thompson, Wesley; Bartsch, Hauke; Jernigan, Terry L.; Dale, Anders M.; Akshoomoff, Natacha; Chang, Linda; Ernst, Thomas; Keating, Brian; Amaral, David; Sowell, Elizabeth; Kaufmann, Walter; Van Zijl, Peter; Mostofsky, Stewart; Casey, B.J.; Ruberry, Erika J.; Powers, Alisa; Rosen, Bruce; Kenet, Tal; Frazier, Jean; Kennedy, David; Gruen, Jeffrey

    2012-01-01

    It is now recognized that a number of cognitive, behavioral, and mental health outcomes across the lifespan can be traced to fetal development. Although the direct mediation is unknown, the substantial variance in fetal growth, most commonly indexed by birth weight, may affect lifespan brain development. We investigated effects of normal variance in birth weight on MRI-derived measures of brain development in 628 healthy children, adolescents, and young adults in the large-scale multicenter Pediatric Imaging, Neurocognition, and Genetics study. This heterogeneous sample was recruited through geographically dispersed sites in the United States. The influence of birth weight on cortical thickness, surface area, and striatal and total brain volumes was investigated, controlling for variance in age, sex, household income, and genetic ancestry factors. Birth weight was found to exert robust positive effects on regional cortical surface area in multiple regions as well as total brain and caudate volumes. These effects were continuous across birth weight ranges and ages and were not confined to subsets of the sample. The findings show that (i) aspects of later child and adolescent brain development are influenced at birth and (ii) relatively small differences in birth weight across groups and conditions typically compared in neuropsychiatric research (e.g., Attention Deficit Hyperactivity Disorder, schizophrenia, and personality disorders) may influence group differences observed in brain parameters of interest at a later stage in life. These findings should serve to increase our attention to early influences. PMID:23169628

  19. Genetic variations of FACL4 have no obvious influence on cognitive ability in young Chinese children.

    PubMed

    Zhang, Kejin; Zheng, Zijian; An, Caiyan; Gao, Xiaocai; Zhang, Fuchang

    2010-06-30

    The influence of genetic variants of FACL4 on individual cognitive ability was examined in a random sample of 213 boys and 224 girls. Both conventional genetic methods and analysis of variance were applied in this study. We found no significant relationship between FACL4 and cognitive function. PMID:20452052

  20. Herbivore attack in Casearia nitida influenced by plant ontogenetic variation in foliage quality and plant architecture.

    PubMed

    Boege, Karina

    2005-03-01

    Traits influencing plant quality as food and/or shelter for herbivores may change during plant ontogeny, and as a consequence, influence the amount of herbivory that plants receive as they develop. In this study, differences in herbivore density and herbivory were evaluated for two ontogenetic stages of the tropical tree Casearia nitida. To assess plant ontogenetic differences in foliage quality as food for herbivores, nutritional and defensive traits were evaluated in saplings and reproductive trees. Predatory arthropods were quantified and the foraging preferences of a parasitoid wasp of the genus Zacremnops were assessed. In addition, survival rates of lepidopteran herbivores (Geometridae) were evaluated experimentally. Herbivore density was three times higher and herbivory was 66% greater in saplings than in reproductive trees. Accordingly, concentrations of total foliar phenolics were higher in reproductive trees than in saplings, whereas leaf toughness, water and nitrogen concentration did not vary between ontogenetic stages. Survival rates of lepidopteran larvae exposed to natural enemies were equivalent in reproductive trees and saplings. Given the greater herbivore density on saplings, equal survival rates implied a greater foraging effort of predators on reproductive trees. Furthermore, observed foraging of parasitoid wasps was restricted to reproductive trees. I propose that herbivore density, and as a consequence, leaf damage were lower in reproductive trees than in saplings due to both traits influencing food quality, and architectural or unmeasured indirect defensive traits influencing foraging preference of natural enemies of herbivores. PMID:15742219

  1. Influences of Vowel and Tone Variation on Emergent Word Knowledge: A Cross-Linguistic Investigation

    ERIC Educational Resources Information Center

    Singh, Leher; Hui, Tam Jun; Chan, Calista; Golinkoff, Roberta Michnick

    2014-01-01

    To learn words, infants must be sensitive to native phonological contrast. While lexical tone predominates as a source of phonemic contrast in human languages, there has been little investigation of the influences of lexical tone on word learning. The present study investigates infants' sensitivity to tone mispronunciations in two groups of…

  2. Subjective analysis of exercise-induced changes in back dimensions of the horse: The influence of saddle-fit, rider skill and work quality.

    PubMed

    Greve, Line; Murray, Rachel; Dyson, Sue

    2015-10-01

    Recommendations concerning saddle-fit are empirical rather than based on scientific information. A saddle needs to fit the horse in motion, but there has been no investigation of whether the thoracolumbar region changes in dimensions in association with exercise. The objectives of this study were to quantify exercise-induced back dimension changes and to describe the association with work quality, saddle-fit and rider skill. Sixty-three sports horses in regular work were assessed prospectively in a non-random, cross-sectional survey. Thoracolumbar dimensions/symmetries were measured at predetermined sites before and immediately after a 30 min exercise period; widths for two levels at each site were measured and the shape-ratio calculated. The work quality and rider skill were graded and the presence of lameness and saddle-fit were recorded. Descriptive statistics, univariable and multivariable mixed-effect linear regression were performed to assess the relationship between horse-saddle-rider factors and changes in back dimensions. The mean back width after ridden exercise was greater compared with before exercise. Mean changes were greater in horses working correctly vs. those not working correctly, in those with correctly-fitting vs. ill-fitting saddles, and in horses ridden by good > moderately > poorly skilled riders. Back-width changes were significantly associated with saddle-fit. The back dimensions of horses working correctly change transiently with work. If a saddle does not fit properly before exercise, this increase in size does not occur. Saddle-fit should be assessed both before and after exercise to ensure correct fit.

  3. The covariance between genetic and environmental influences across ecological gradients: reassessing the evolutionary significance of countergradient and cogradient variation.

    PubMed

    Conover, David O; Duffy, Tara A; Hice, Lyndie A

    2009-06-01

    Patterns of phenotypic change across environmental gradients (e.g., latitude, altitude) have long captivated the interest of evolutionary ecologists. The pattern and magnitude of phenotypic change is determined by the covariance between genetic and environmental influences across a gradient. Cogradient variation (CoGV) occurs when covariance is positive: that is, genetic and environmental influences on phenotypic expression are aligned and their joint influence accentuates the change in mean trait value across the gradient. Conversely, countergradient variation (CnGV) occurs when covariance is negative: that is, genetic and environmental influences on phenotypes oppose one another, thereby diminishing the change in mean trait expression across the gradient. CnGV has so far been found in at least 60 species, with most examples coming from fishes, amphibians, and insects across latitudinal or altitudinal gradients. Traits that display CnGV most often involve metabolic compensation, that is, the elevation of various physiological rates processes (development, growth, feeding, metabolism, activity) to counteract the dampening effect of reduced temperature, growing season length, or food supply. Far fewer examples of CoGV have been identified (11 species), and these most often involve morphological characters. Increased knowledge of spatial covariance patterns has furthered our understanding of Bergmann size clines, phenotypic plasticity, species range limits, tradeoffs in juvenile growth rate, and the design of conservation strategies for wild species. Moreover, temporal CnGV explains some cases of an apparent lack of phenotypic response to directional selection and provides a framework for predicting evolutionary responses to climate change. PMID:19566705

  4. Chemical variation in Jacobaea vulgaris is influenced by the interaction of season and vegetation successional stage.

    PubMed

    Carvalho, Sabrina; Macel, Mirka; Mulder, Patrick P J; Skidmore, Andrew; van der Putten, Wim H

    2014-03-01

    Knowledge on spatio-temporal dynamics of plant primary and secondary chemistry under natural conditions is important to assess how plant defence varies in real field conditions. Plant primary and secondary chemistry is known to vary with both season and vegetation successional stage, however, in few studies these two sources of variation have been examined in combination. Here we examine variations in primary and secondary chemistry of Jacobaea vulgaris (Asteraceae) throughout the growing season in early, mid, and late stages of secondary succession following land abandonment using a well-established chronosequence in The Netherlands. We investigated primary and secondary chemistry of both leaves and flowers, in order to determine if patterns during seasonal (phenological) development may differ among successional stages. The chemical concentration of primary and secondary chemistry compounds in J. vulgaris varied throughout the season and was affected by vegetation succession stage. Concentrations of pyrrolizidine alkaloid (PA) tertiary-amines were highest in flowers during early Summer and in fields that had been abandoned ten to twenty years ago. PA N-oxide concentrations of both leaves and flowers, on the other hand increased with the progression of both season and succession. In Spring and early Summer chlorophyll concentrations were highest, especially in the oldest fields of the chronosequence. During phenological development, nitrogen concentration increased in flowers and decreased in leaves revealing allocation of nutrients from vegetative to reproductive plant parts throughout the growing season. The highest concentrations of N-oxides and chlorophylls were detected in older fields. Thus, our results suggest that variations in plant patterns of nutritional and defence compounds throughout the growing season are depending on successional context.

  5. Genetic variation in bitter taste receptor genes influences the foraging behavior of plateau zokor (Eospalax baileyi).

    PubMed

    Zhao, Fang; Zhang, Tongzuo; Xie, Jiuxiang; Zhang, Shoudong; Nevo, Eviatar; Su, Jianping; Lin, Gonghua

    2016-04-01

    The ability to detect bitter tastes is important for animals; it can help them to avoid ingesting harmful substances. Bitter taste perception is mainly mediated by bitter taste receptor proteins, which are encoded by members of the Tas2r gene family and vary with the dietary preference of a specific species. Although individuals with different genotypes differ in bitterness recognition capability, little is known about the relationship between genetic variation and food selection tendencies at the intraspecific level. In this study, we examined the relationship between genotypes and diet in plateau zokor (Eospalax baileyi), a subterranean rodent endemic to the Qinghai-Tibet Plateau that caches food for the winter. We assayed the composition and taste profile of each plant contained in temporary caches and vicinity quadrats, which were representative of selected and available food, respectively. Bitter plant selection indices (E bitter) were estimated. We also sequenced 26 candidate Tas2r genes from zokors and determined their relationships with the E bitter of their caches. We identified four key results: (1) zokors varied considerably in both bitter food preference and Tas2r sequences; (2) five genes (zTas2r115,zTas2r119,zTas2r126,zTas2r134, and zTas2r136) exhibited allelic variation that was significantly associated with E bitter; (3) synonymous SNPs, nonsynonymous SNPs, and pseudogenization are involved in the genotype-phenotype relationship; (4) the minor genotypes of zTas2r115,zTas2r134, and zTas2r136 and the major genotypes of zTas2r119 and zTas2r126 cached more bitter plants. Our results link Tas2r variation with food selection behavior at the population level for the first time. PMID:27110349

  6. NOx, VOCs, and meteorological conditions influencing ozone variation in Kaohsiung, Taiwan

    NASA Astrophysics Data System (ADS)

    Kuo, Y.; Yu, H.; Wang, S.; Jang, C.

    2011-12-01

    The complex process of ozone formation, its precursor compounds (volatile organic compounds (VOCs) and nitrogen oxides (NOx)) emissions, accompanying with meteorological conditions, makes ozone difficult to control. Dynamic factor analysis (DFA) and min/max autocorrelation factor analysis (MAFA) especially designed for time series data, which tolerate missing values, allow analyzing short, non-stationary multivariate time series that can contain meteorological and gaseous pollutant explanatory variables. The first min/max autocorrelation factor axis (MAF 1) is the major trend which shows regular daily fluctuation; while the second common trend of DFM is similar to it. For both episodes, temperature, relative humidity, and wind speed are highly correlated with MAF 1, indicating these meteorological conditions mainly affect the ozone variability. According to the best DFM, temperature, wind speed, and NOx in high ozone episode and temperature and NOx in the low ozone episode highly affect the ozone variability. The best DFM shows explanatory variables rather than common trends play important roles in describing ozone variation. Comparing effects of VOCs and NOx on O3 variation, ozone variation is relatively sensitive to VOCs in the low ozone episode and is relatively sensitive to NOx in high zone episode. The results of DFM and MAFA show that the ozone variations of Mei-nung stations were distinguished from other stations for both ozone episodes. The resulting dynamic factor models yielded good predictions of observed ozone series (overall coefficient of efficiency (Ceff) = 0.90 in low ozone episode and Ceff = 0.95 in the high ozone episode). In this study, DFA and NAFA provides a quantitative insight into the spatial distributions of VOCs, NOx, and meteorological conditions effects on ozone.
    Table 1. Correlations between explanatory variables and the three significant min/max autocorrelation factor (MAF) axes.

  7. Influence of ocean tides on the diurnal and semidiurnal earth rotation variations from VLBI observations

    NASA Astrophysics Data System (ADS)

    Gubanov, V. S.; Kurdubov, S. L.

    2015-05-01

    The International astrogeodetic standard IERS Conventions (2010) contains a model of the diurnal and semidiurnal variations in Earth rotation parameters (ERPs), the pole coordinates and the Universal Time, arising from lunisolar tides in the world ocean. This model was constructed in the mid-1990s through a global analysis of Topex/Poseidon altimetry. The goal of this study is to try to estimate the parameters of this model by processing all the available VLBI observations on a global network of stations over the last 35 years performed within the framework of IVS (International VLBI Service) geodetic programs. The complexity of the problemlies in the fact that the sought-for corrections to the parameters of this model lie within 1 mm and, thus, are at the limit of their detectability by all currently available methods of ground-based positional measurements. This requires applying universal software packages with a high accuracy of reduction calculations and a well-developed system of controlling the simultaneous adjustment of observational data to analyze long series of VLBI observations. This study has been performed with the QUASAR software package developed at the Institute of Applied Astronomy of the Russian Academy of Sciences. Although the results obtained, on the whole, confirm a high accuracy of the basic model in the IERS Conventions (2010), statistically significant corrections that allow this model to be refined have been detected for some harmonics of the ERP variations.

  8. Long-term global temperature variations under the influence of different cosmophysical factors

    NASA Astrophysics Data System (ADS)

    Biktash, Lilia

    2016-07-01

    We have analyzed different cosmophysical factors which have effect on long-term global temperature variations during solar cycles 20-24. A detailed analysis of total solar irradiance (TSI), the spectral solar ultraviolet emission (UV), space weather and cosmic rays (CRs) have effects on the atmosphere processes. We have shown that increasing of global temperature is likely affected by TSI and UV during solar maxima. During the descending phases of these solar cycles the interplanetary magnetic field and long-lasting solar wind high speed streams occurred frequently and were the primary contributors to minimize of CRs effect on the Earth's atmosphere. In this case global temperature is increased extra as result of increase in the atmosphere's transparency. We show that there are a few effective physical mechanisms of the action of solar activity and space weather on the global temperature. TSI and CRs play essential role in climate change and main part of climate variations can be explained by the mechanism of action TSI and CRs modulated by the solar activity on the state of lower atmosphere and meteorological parameters.

  9. Influence of linear depth variation on Poincare, Kelvin, and Rossby waves

    SciTech Connect

    Staniforth, A.N. ); Williams, R.T.; Neta, B. )

    1993-04-01

    Exact solutions to the linearized shallow-water equations in a channel with linear depth variation and a mean flow are obtained in terms of confluent hypergeometric functions. These solutions are the generalization to finite s (depth variation parameter) of the approximate solutions for infinitesimal s. The equations also respect an energy conservation principle (and the normal modes are thus neutrally stable) in contradistinction to those of previous studies. They are evaluated numerically for a range in s from s = 0.1 to s = 1.95, and the range of validity of previously derived approximate solutions is established. For small s the Kelvin and Poincare' solutions agree well with those of Hyde, which were obtained by expanding in s. For finite s the solutions differ significantly from the Hyde expansions, and the magnitude of the phase speed decreases as s increases. The Rossby wave phase speeds are close to those obtained when the depth is linearized although the difference increases with s. The eigenfunctions become more distorted as s increases so that the largest amplitude and the smallest scale occur near the shallowest boundary. The negative Kelvin wave has a very unusual behavior as s increases.

  10. Case study of polychlorinated naphthalene emissions and factors influencing emission variations in secondary aluminum production.

    PubMed

    Jiang, Xiaoxu; Liu, Guorui; Wang, Mei; Liu, Wenbin; Tang, Chen; Li, Li; Zheng, Minghui

    2015-04-01

    Secondary aluminum production has been recognized as an important source of polychlorinated naphthalenes (PCNs). Large variations in PCN emissions as the smelting process proceeds have not been determined. In this study, solid and gaseous discharges, including fly ash, slag, and stack gas samples collected from four secondary smelting plants during different smelting stages were analyzed for PCNs. The average emission factor of ∑(1-8)PCNs to air was calculated to be 17.4 mg t(-1), with a range of 4.3-29.5 mg t(-1). The average emission factors of ∑(1-8)PCNs from fly ash and slag were 55.5 ng t(-1) and 0.13 ng t(-1), respectively. The derived emission factors may enable a more accurate estimation of annual emissions and a more comprehensive knowledge of the distribution of PCNs emitted from secondary aluminum production. The emission levels and characteristics of PCNs during different smelting stages were compared. Possible factors, including the organic impurities from aluminum scrap, fuel, and chloride additives, which could contribute to variations in PCN emissions and characteristics were discussed. These results may provide useful information for developing better control strategies for reducing PCN emissions in secondary aluminum production.

  11. Genotypic variation influences reproductive success and thermal stress tolerance in the reef building coral, Acropora palmata

    NASA Astrophysics Data System (ADS)

    Baums, I. B.; Devlin-Durante, M. K.; Polato, N. R.; Xu, D.; Giri, S.; Altman, N. S.; Ruiz, D.; Parkinson, J. E.; Boulay, J. N.

    2013-09-01

    The branching coral Acropora palmata is a foundation species of Caribbean reefs that has been decimated in recent decades by anthropogenic and natural stressors. Declines in population density and genotypic diversity likely reduce successful sexual reproduction in this self-incompatible hermaphrodite and might impede recovery. We investigated variation among genotypes in larval development under thermally stressful conditions. Six two-parent crosses and three four-parent batches were reared under three temperatures and sampled over time. Fertilization rates differed widely with two-parent crosses having lower fertilization rates (5-56 %, mean 22 % ± 22 SD) than batches (from 31 to 87 %, mean 59 % ± 28 SD). Parentage analysis of larvae in batch cultures showed differences in gamete compatibility among parents, coinciding with significant variation in both sperm morphology and egg size. While all larval batches developed more rapidly at increased water temperatures, rate of progression through developmental stages varied among batches, as did swimming speed. Together, these results indicate that loss of genotypic diversity exacerbates already severe limitations in sexual reproductive success of A. palmata. Nevertheless, surviving parental genotypes produce larvae that do vary in their phenotypic response to thermal stress, with implications for adaptation, larval dispersal and population connectivity in the face of warming sea surface temperatures.

  12. The Influence of Variation in Time and HCl Concentration to the Glucose Produced from Kepok Banana

    NASA Astrophysics Data System (ADS)

    Widodo M, Rohman; Noviyanto, Denny; RM, Faisal

    2016-01-01

    Kepok banana (Musa paradisiaca) is a plant that has many advantagesfrom its fruit, stems, leaves, flowers and cob. However, we just tend to take benefit from the fruit. We grow and harvest the fruit without taking advantages from other parts. So they would be a waste or detrimental to animal nest if not used. The idea to take the benefit from the banana crop yields, especially cob is rarely explored. This study is an introduction to the use of banana weevil especially from the glucose it contains. This study uses current methods of hydrolysis using HCl as a catalyst with the concentration variation of 0.4 N, 0.6 N and 0.8 N and hydrolysis times variation of 20 minutes, 25 minutes and 30 minutes. The stages in the hydrolysis include preparation of materials, the process of hydrolysis and analysis of test results using Fehling and titrate with standard glucose solution. HCl is used as a catalyst because it is cheaper than the enzyme that has the same function. NaOH 60% is used for neutralizing the pH of the filtrate result of hydrolysis. From the results of analysis, known thatthe biggest yield of glucose is at concentration 0.8 N and at 30 minutes reaction, it contains 6.25 gram glucose / 20 gram dry sampel, and the convertion is 27.22% at 20 gram dry sampel.

  13. Influence of variations in extratropical wintertime teleconnections on Northern Hemisphere temperature

    SciTech Connect

    Hurrell, J.W.

    1996-03-15

    Pronounced changes in the wintertime atmospheric circulation have occurred since the mid-1970s over the ocean basins of the Northern Hemisphere, and these changes have had a profound effect on surface temperatures. The variations over the North Atlantic are related to changes in the North Atlantic Oscillation (NAO), while the changes over the North Pacific are linked to the tropics and involve variations in the Aleutian low with teleconnections downstream over North America. Multivariate linear regression is used to show that nearly all of the cooling in the northwest Atlantic and the warming across Europe and downstream over Eurasia since the mid-1970s results from the changes in the NAO, and the NAO accounts for 31% of the hemispheric interannual variance over the past 60 winters. Over the Pacific basin and North America, the temperature anomalies result in part from tropical forcing associated with the El Nino-Southern Oscillation phenomenon but with important feedbacks in the extratropics. The changes in circulation over the past two decades have resulted in a surface temperature anomaly pattern of warmth over the continents and coolness over the oceans. This pattern of temperature change has amplified the observed hemispheric-averaged warming because of it interaction with land and ocean; temperature changes are larger over land compared to the oceans because of the small heat capacity of the former. 13 refs., 5 fig., 2 tab.

  14. On the influence of dynamic stress variations on strain accumulation in fault zones

    NASA Astrophysics Data System (ADS)

    Grigoriev, A. S.; Shilko, E. V.; Astafurov, S. V.; Dimaki, A. V.; Vysotsky, E. M.; Psakhie, S. G.

    2015-10-01

    In this paper, a numerical study of the influence of the stress state of interface of the block medium structural elements on the deformation response of interface to the dynamic impacts. It is shown that the basic characteristics of the stress state determining the deformation response of the interface are the values of shear stress and mean stress. It is found that the dependence of the irreversible displacement at the interface zone initiated by dynamic impact on the reduced shear stress is described by the logistic function. Herewith, the influence of the mean stress and dynamic impact energy on the value of displacement initiated by dynamic impact can be taken into account by dependence of the logistic function numerator on these parameters.

  15. Complex viscosity induced by protein composition variation influences the aroma release of flavored stirred yogurt.

    PubMed

    Saint-Eve, Anne; Juteau, Alexandre; Atlan, Samuel; Martin, Nathalie; Souchon, Isabelle

    2006-05-31

    Dairy protein composition is known to influence the structure and the texture characteristics of yogurt. The objective of the present work was therefore to investigate the impact of protein composition, at a constant protein level, on the physicochemical properties of 4% fat flavored stirred yogurt and, more specifically, on the rheological properties, the microstructure, and the aroma release. The results showed that caseinate-enriched yogurt generally presented changes in their microstructure network and had a higher complex viscosity than whey protein-enriched yogurt. To a lesser extent, the release of the majority of aroma compounds was lower in caseinate-enriched yogurt. It was therefore possible to quantify physicochemical interactions between aroma compounds and proteins. The influence of gel structure on the flavor release was observed and was in agreement with sensory characteristics previously studied for these products.

  16. Genetic variation in a tropical tree species influences the associated epiphytic plant and invertebrate communities in a complex forest ecosystem

    PubMed Central

    Zytynska, Sharon E.; Fay, Michael F.; Penney, David; Preziosi, Richard F.

    2011-01-01

    Genetic differences among tree species, their hybrids and within tree species are known to influence associated ecological communities and ecosystem processes in areas of limited species diversity. The extent to which this same phenomenon occurs based on genetic variation within a single tree species, in a diverse complex ecosystem such as a tropical forest, is unknown. The level of biodiversity and complexity of the ecosystem may reduce the impact of a single tree species on associated communities. We assessed the influence of within-species genetic variation in the tree Brosimum alicastrum (Moraceae) on associated epiphytic and invertebrate communities in a neotropical rainforest. We found a significant positive association between genetic distance of trees and community difference of the epiphytic plants growing on the tree, the invertebrates living among the leaf litter around the base of the tree, and the invertebrates found on the tree trunk. This means that the more genetically similar trees are host to more similar epiphyte and invertebrate communities. Our work has implications for whole ecosystem conservation management, since maintaining sufficient genetic diversity at the primary producer level will enhance species diversity of other plants and animals. PMID:21444307

  17. Influence of variation in combustion conditions on the primary formation of chlorinated organic micropollutants during municipal solid waste combustion

    SciTech Connect

    Wikstroem, E.; Tysklind, M.; Marklund, S.

    1999-12-01

    The aim of this study was to investigate the influence of variation in combustion conditions on the primary formation of organic micropollutants (OMPs). The flue gas samples were taken at a relatively high flue gas temperature (650 C), to enable mechanistic studies on the high temperature formation (primary formation). Eleven experiments were performed in a laboratory scale fluidized bed reactor fed with an artificial municipal solid waste (MSW). The samples were analyzed for nomo- to octachlorinated dibenzo-p-dioxins and dibenzofurans (CDDs/Fs), tri- to decachlorinated biphenyls (CBs), di- to hexachlorinated benzenes (CBzs), and di- to pentachlorinated phenols (CPhs). In addition to chlorinated OMPs, nonchlorinated dibenzo-p-dioxin (DD), dibenzofuran (DF), and biphenyl (BP) were analyzed. The experiments show that variations in the Ce influence the degree of chlorination of the organic micropollutants. A correlation between low CE and formation of non- and low- chlorinated OMPs was seen and a distinct relationship of higher chlorinated homologues and efficient combustion condition. Thus, the DiCDFs and DiCBzs are formed during low combustion efficiency (CE), which the PeCDF and PeCBzs formation take place at higher Ce. The distribution between primary and secondary air is important for the formation of higher CDD/Fs and CBzs. The primary formation of CDDs and CDFs is through different mechanisms. The CDDs are mainly formed by condensation of CPhs, while the CDFs are formed through a non- or a low-chlorinated precursor followed by further chlorination reactions.

  18. Investigation of the spatiotemporal variation and influencing factors on fine particulate matter and carbon monoxide concentrations near a road intersection

    NASA Astrophysics Data System (ADS)

    Wang, Zhanyong; Lu, Qing-Chang; He, Hong-Di; Wang, Dongsheng; Gao, Ya; Peng, Zhong-Ren

    2016-05-01

    The minute-scale variations of fine particulate matter (PM2.5) and carbon monoxide (CO) concentrations near a road intersection in Shanghai, China were investigated to identify the influencing factors at three traffic periods. Measurement results demonstrate a synchronous variation of pollutant concentrations at the roadside and setbacks, and the average concentration of PM2.5 at the roadside is 7% (44% for CO) higher than that of setbacks within 500 m of the intersection. The pollution level at traffic peak periods is found to be higher than that of off-peak periods, and the morning peak period is found to be the most polluted due to a large amount of diesel vehicles and unfavorable dispersion conditions. Partial least square regressions were constructed for influencing factors and setback pollutant concentrations, and results indicate that meteorological factors are the most significant, followed by setback distance from the intersection and traffic factors. CO is found to be sensitive to distance from the traffic source and vehicle type, and highly dependent on local traffic conditions, whereas PM2.5 originates more from other sources and background levels. These findings demonstrate the importance of localized factors in understanding spatiotemporal patterns of air pollution at intersections, and support decision makers in roadside pollution management and control.

  19. Genetic variation in a tropical tree species influences the associated epiphytic plant and invertebrate communities in a complex forest ecosystem.

    PubMed

    Zytynska, Sharon E; Fay, Michael F; Penney, David; Preziosi, Richard F

    2011-05-12

    Genetic differences among tree species, their hybrids and within tree species are known to influence associated ecological communities and ecosystem processes in areas of limited species diversity. The extent to which this same phenomenon occurs based on genetic variation within a single tree species, in a diverse complex ecosystem such as a tropical forest, is unknown. The level of biodiversity and complexity of the ecosystem may reduce the impact of a single tree species on associated communities. We assessed the influence of within-species genetic variation in the tree Brosimum alicastrum (Moraceae) on associated epiphytic and invertebrate communities in a neotropical rainforest. We found a significant positive association between genetic distance of trees and community difference of the epiphytic plants growing on the tree, the invertebrates living among the leaf litter around the base of the tree, and the invertebrates found on the tree trunk. This means that the more genetically similar trees are host to more similar epiphyte and invertebrate communities. Our work has implications for whole ecosystem conservation management, since maintaining sufficient genetic diversity at the primary producer level will enhance species diversity of other plants and animals.

  20. Porous gravity currents: A survey to determine the joint influence of fluid rheology and variations of medium properties

    NASA Astrophysics Data System (ADS)

    Ciriello, Valentina; Longo, Sandro; Chiapponi, Luca; Di Federico, Vittorio

    2016-06-01

    We develop a model to grasp the combined effect of rheology and spatial stratifications on two-dimensional non-Newtonian gravity-driven flow in porous media. We consider a power-law constitutive equation for the fluid, and a monomial variation of permeability and porosity along the vertical direction (transverse to the flow) or horizontal direction (parallel to the flow). Under these assumptions, similarity solutions are derived in semi-analytical form for thin gravity currents injected into a two-dimensional porous medium and having constant or time-varying volume. The extent and shape of the porous domain affected by the injection is significantly influenced by the interplay of model parameters. These describe the fluid (flow behaviour index n), the spatial heterogeneity (coefficients β, γ, δ, ω for variations of permeability and porosity in the horizontal or vertical direction), and the type of release (volume exponent α). Theoretical results are validated against two sets of experiments with α = 1 (constant inflow) conducted with a stratified porous medium (simulated by superimposing layers of glass beads of different diameter) and a Hele-Shaw analogue for power-law fluid flow, respectively. In the latter case, a recently established Hele-Shaw analogy is extended to the variation of properties parallel to the flow direction. Comparison with experimental results shows that the proposed model is able to capture the propagation of the current front and the current profile.

  1. Variation partitioning of diatom species data matrices: Understanding the influence of multiple factors on benthic diatom communities in tropical streams.

    PubMed

    Bere, Taurai; Mangadze, Tinotenda; Mwedzi, Tongai

    2016-10-01

    Elucidating the confounding influence of multiple environmental factors on benthic diatom communities is important in developing water quality predictive models for better guidance of stream management efforts. The objective of this study was to explore the relative impact of metal pollution and hydromorphological alterations in, addition to nutrient enrichment and organic pollution, on diatom taxonomic composition with the view to improve stream diatom-based water quality inference models. Samples were collected twice at 20 sampling stations in the tropical Manyame Catchment, Zimbabwe. Diatom, macroinvertebrate communities and environmental factors were sampled and analysed. The variations in diatom community composition explained by different categories of environmental factors were analysed using canonical correspondence analysis using variance partitioning (partial CCA). The following variations were explained by the different predictor matrices: nutrient levels and organic pollution - 10.4%, metal pollution - 8.3% and hydromorphological factors - 7.9%. Thus, factors other than nutrient levels and organic pollution explain additional significant variation in these diatom communities. Development of diatom-based stream water quality inference models that incorporate metal pollution and hydromorphological alterations, where these are key issues, is thus deemed necessary.

  2. Variation partitioning of diatom species data matrices: Understanding the influence of multiple factors on benthic diatom communities in tropical streams.

    PubMed

    Bere, Taurai; Mangadze, Tinotenda; Mwedzi, Tongai

    2016-10-01

    Elucidating the confounding influence of multiple environmental factors on benthic diatom communities is important in developing water quality predictive models for better guidance of stream management efforts. The objective of this study was to explore the relative impact of metal pollution and hydromorphological alterations in, addition to nutrient enrichment and organic pollution, on diatom taxonomic composition with the view to improve stream diatom-based water quality inference models. Samples were collected twice at 20 sampling stations in the tropical Manyame Catchment, Zimbabwe. Diatom, macroinvertebrate communities and environmental factors were sampled and analysed. The variations in diatom community composition explained by different categories of environmental factors were analysed using canonical correspondence analysis using variance partitioning (partial CCA). The following variations were explained by the different predictor matrices: nutrient levels and organic pollution - 10.4%, metal pollution - 8.3% and hydromorphological factors - 7.9%. Thus, factors other than nutrient levels and organic pollution explain additional significant variation in these diatom communities. Development of diatom-based stream water quality inference models that incorporate metal pollution and hydromorphological alterations, where these are key issues, is thus deemed necessary. PMID:27320742

  3. Variation in Inflammatory Response during Pneumococcal Infection Is Influenced by Host-Pathogen Interactions but Associated with Animal Survival

    PubMed Central

    Escudero, Laura; Sylvius, Nicolas; Norman, Martin; Henriques-Normark, Birgitta

    2016-01-01

    Inflammation is a crucial part of innate immune responses but, if imbalanced, can lead to serious clinical conditions or even death. Cytokines regulate inflammation, and studies report their impact on clinical outcome. However, host and pathogen genetic backgrounds influence cytokine production, making it difficult to evaluate which inflammatory profiles (if any) relate to improved prognosis. Streptococcus pneumoniae is a common human pathogen associated with asymptomatic nasopharyngeal carriage. Infrequently, it can lead to a wide range of diseases with high morbidity and mortality rates. Studies show that both pneumococcal serotype and host genetic background affect the development of disease and contribute to variation in inflammatory responses. In this study, we investigated the impact of the host and pneumococcal genetic backgrounds on pulmonary cytokine responses and their relationship to animal survival. Two inbred mouse strains, BALB/c and CBA/Ca, were infected with 10 pneumococcal strains, and the concentrations of six pulmonary cytokines were measured at 6 h and 24 h postinfection. Collected data were analyzed by principal-component analysis to identify whether there is any pattern in the observed cytokine variation. Our results show that host-pneumococcus combination was at the core of observed variation in cytokine responses, yet the resulting cytokine profile discriminated only between survivors and fatalities but not mouse or pneumococcal strains used during infection. Therefore, our results indicate that although alternative inflammatory profiles are generated during pneumococcal infection, a common pattern emerged, which determined the clinical outcome of pneumococcal infections. PMID:26787718

  4. Variation in Inflammatory Response during Pneumococcal Infection Is Influenced by Host-Pathogen Interactions but Associated with Animal Survival.

    PubMed

    Jonczyk, Magda S; Escudero, Laura; Sylvius, Nicolas; Norman, Martin; Henriques-Normark, Birgitta; Andrew, Peter W

    2016-04-01

    Inflammation is a crucial part of innate immune responses but, if imbalanced, can lead to serious clinical conditions or even death. Cytokines regulate inflammation, and studies report their impact on clinical outcome. However, host and pathogen genetic backgrounds influence cytokine production, making it difficult to evaluate which inflammatory profiles (if any) relate to improved prognosis.Streptococcus pneumonia is a common human pathogen associated with asymptomatic nasopharyngeal carriage. Infrequently, it can lead to a wide range of diseases with high morbidity and mortality rates. Studies show that both pneumococcal serotype and host genetic background affect the development of disease and contribute to variation in inflammatory responses. In this study, we investigated the impact of the host and pneumococcal genetic backgrounds on pulmonary cytokine responses and their relationship to animal survival. Two inbred mouse strains, BALB/c and CBA/Ca, were infected with 10 pneumococcal strains, and the concentrations of six pulmonary cytokines were measured at 6 h and 24 h postinfection. Collected data were analyzed by principal-component analysis to identify whether there is any pattern in the observed cytokine variation. Our results show that host-pneumococcus combination was at the core of observed variation in cytokine responses, yet the resulting cytokine profile discriminated only between survivors and fatalities but not mouse or pneumococcal strains used during infection. Therefore, our results indicate that although alternative inflammatory profiles are generated during pneumococcal infection, a common pattern emerged, which determined the clinical outcome of pneumococcal infections.

  5. Characterisation of the influence of genetic variations on the enzyme activity of a recombinant human glycine N-acyltransferase.

    PubMed

    van der Sluis, Rencia; Badenhorst, Christoffel P S; van der Westhuizen, Francois H; van Dijk, Alberdina A

    2013-02-25

    Human glycine N-acyltransferase (human GLYAT) detoxifies a wide range of endogenous and xenobiotic metabolites, including benzoate and salicylate. Significant inter-individual variation exists in glycine conjugation capacity. The molecular basis for this variability is not known. To investigate the influence of single nucleotide polymorphisms (SNPs) in the GLYAT coding sequence on enzyme activity, we expressed and characterised a recombinant human GLYAT. Site-directed mutagenesis was used to generate six non-synonymous SNP variants of the enzyme (K16N; S17T; R131H; N156S; F168L; R199C). The variants were expressed, purified, and enzymatically characterised. The enzyme activities of the K16N, S17T and R131H variants were similar to that of the wild-type, whereas the N156S variant was more active, the F168L variant less active, and the R199C variant was inactive. We also generated an E227Q mutant, which lacks the catalytic residue proposed by Badenhorst et al. (2012). This mutant was inactive compared to the wild-type recombinant human GLYAT. A molecular model of human GLYAT containing coenzyme A (CoA) was generated which revealed that the inactivity of the R199C variant could be due to the substitution of the highly conserved Arg(199) and destabilisation of an α-loop-α motif which is important for substrate binding in the GNAT superfamily. The finding that SNP variations in the human GLYAT gene influence the kinetic properties of the enzyme may explain some of the inter-individual variation in glycine conjugation capacity, which is relevant to the metabolism of xenobiotics such as aspirin and the industrial solvent xylene, and to the treatment of some metabolic disorders. PMID:23237781

  6. Variations in the influence of parental socialization of anxiety among clinic referred children.

    PubMed

    Holly, Lindsay E; Pina, Armando A

    2015-06-01

    This study examined the relations between parental socialization of child anxious behaviors (i.e., reinforcement, punishment, modeling, transmission of information) and child anxiety and related problems at varying child sensitivity levels. Data corresponding to 70 clinic-referred children (M age = 9.86 years; 50% girls; 49% Hispanic/Latino, 51% Caucasian) showed that for children with low (but not high) anxiety sensitivity, anxiety-related parental socialization behaviors were associated with more child anxiety and depression symptoms. Findings also indicated that parental socialization of anxious behaviors and anxiety sensitivity functioned similarly in the prediction of anxiety and depression across Caucasian and Hispanic/Latino children. There were no significant mean level variations across child sociodemographic characteristics in general, but anxiety-promoting parenting behaviors were twice as high in Hispanic/Latino compared to Caucasian families.

  7. Influence of quaternary sea-level variations on a land bird endemic to Pacific atolls.

    PubMed

    Cibois, Alice; Thibault, Jean-Claude; Pasquet, Eric

    2010-11-22

    Little is known about the effect of quaternary climate variations on organisms that inhabited carbonate islands of the Pacific Ocean, although it has been suggested that one or several uplifted islands provided shelter for terrestrial birds when sea-level reached its highest. To test this hypothesis, we investigated the history of colonization of the Tuamotu reed-warbler (Acrocephalus atyphus) in southeastern Polynesia, and found high genetic structure between the populations of three elevated carbonate islands. Estimates of time since divergence support the hypothesis that these islands acted as refugia during the last interglacial maximum. These findings are particularly important for defining conservation priorities on atolls that endure the current trend of sea-level rise owing to global warming. PMID:20554555

  8. One hundred years of Arctic surface temperature variation due to anthropogenic influence

    PubMed Central

    Fyfe, John C.; von Salzen, Knut; Gillett, Nathan P.; Arora, Vivek K.; Flato, Gregory M.; McConnell, Joseph R.

    2013-01-01

    Observations show that Arctic-average surface temperature increased from 1900 to 1940, decreased from 1940 to 1970, and increased from 1970 to present. Here, using new observational data and improved climate models employing observed natural and anthropogenic forcings, we demonstrate that contributions from greenhouse gas and aerosol emissions, along with explosive volcanic eruptions, explain most of this observed variation in Arctic surface temperature since 1900. In addition, climate model simulations without natural and anthropogenic forcings indicate very low probabilities that the observed trends in each of these periods were due to internal climate variability alone. Arctic climate change has important environmental and economic impacts and these results improve our understanding of past Arctic climate change and our confidence in future projections. PMID:24025852

  9. Influence of quaternary sea-level variations on a land bird endemic to Pacific atolls.

    PubMed

    Cibois, Alice; Thibault, Jean-Claude; Pasquet, Eric

    2010-11-22

    Little is known about the effect of quaternary climate variations on organisms that inhabited carbonate islands of the Pacific Ocean, although it has been suggested that one or several uplifted islands provided shelter for terrestrial birds when sea-level reached its highest. To test this hypothesis, we investigated the history of colonization of the Tuamotu reed-warbler (Acrocephalus atyphus) in southeastern Polynesia, and found high genetic structure between the populations of three elevated carbonate islands. Estimates of time since divergence support the hypothesis that these islands acted as refugia during the last interglacial maximum. These findings are particularly important for defining conservation priorities on atolls that endure the current trend of sea-level rise owing to global warming.

  10. One hundred years of Arctic surface temperature variation due to anthropogenic influence.

    PubMed

    Fyfe, John C; von Salzen, Knut; Gillett, Nathan P; Arora, Vivek K; Flato, Gregory M; McConnell, Joseph R

    2013-01-01

    Observations show that Arctic-average surface temperature increased from 1900 to 1940, decreased from 1940 to 1970, and increased from 1970 to present. Here, using new observational data and improved climate models employing observed natural and anthropogenic forcings, we demonstrate that contributions from greenhouse gas and aerosol emissions, along with explosive volcanic eruptions, explain most of this observed variation in Arctic surface temperature since 1900. In addition, climate model simulations without natural and anthropogenic forcings indicate very low probabilities that the observed trends in each of these periods were due to internal climate variability alone. Arctic climate change has important environmental and economic impacts and these results improve our understanding of past Arctic climate change and our confidence in future projections. PMID:24025852

  11. Influence of quaternary sea-level variations on a land bird endemic to Pacific atolls

    PubMed Central

    Cibois, Alice; Thibault, Jean-Claude; Pasquet, Eric

    2010-01-01

    Little is known about the effect of quaternary climate variations on organisms that inhabited carbonate islands of the Pacific Ocean, although it has been suggested that one or several uplifted islands provided shelter for terrestrial birds when sea-level reached its highest. To test this hypothesis, we investigated the history of colonization of the Tuamotu reed-warbler (Acrocephalus atyphus) in southeastern Polynesia, and found high genetic structure between the populations of three elevated carbonate islands. Estimates of time since divergence support the hypothesis that these islands acted as refugia during the last interglacial maximum. These findings are particularly important for defining conservation priorities on atolls that endure the current trend of sea-level rise owing to global warming. PMID:20554555

  12. Variation at the fragile X locus does not influence susceptibility to bipolar disorder

    SciTech Connect

    Craddock, N.; Daniels, J.; McGuffin, P.

    1994-06-15

    Over the last 20 years several pedigrees have been reported which are suggestive of linkage between susceptibility to bipolar disorder and markers on chromosome Xq28. Other workers have failed to replicate these reports and the methodology of the positive reports has been criticized. Recently there have been several reports of an association between fragile X (FRA(X)) and affective disorder within families and in unrelated individuals compared with controls. Such reports could be consistent with the Xq28 marker reports because FRA(X) maps to Xq27.3. We report a study at the FRA(X) CGG repeat locus in 79 unrelated Caucasian bipolar probands without fragile X syndrome and 77 unrelated controls. We found no evidence that variation at this locus confers susceptibility to bipolar disorder. 28 refs., 1 fig.

  13. Vegetation structure and fire weather influence variation in burn severity and fuel consumption during peatland wildfires

    NASA Astrophysics Data System (ADS)

    Davies, G. M.; Domènech, R.; Gray, A.; Johnson, P. C. D.

    2015-09-01

    Temperate peatland wildfires are of significant environmental concern but information on their environmental effects is lacking. We assessed variation in burn severity and fuel consumption within and between wildfires that burnt British moorlands in 2011 and 2012. We adapted the Composite Burn Index (pCBI) to provide semi-quantitative estimates of burn severity. Pre- and post-fire surface (shrubs and graminoids) and ground (litter, moss, duff) fuel loads associated with large wildfires were assessed using destructive sampling and analysed using a Generalised Linear Mixed Model (GLMM). Consumption during wildfires was compared with published estimates of consumption during prescribed burns. Burn severity and fuel consumption were related to fire weather, assessed using the Canadian Fire Weather Index System (FWI System), and pre-fire fuel structure. pCBI varied 1.6 fold between, and up to 1.7 fold within, wildfires. pCBI was higher where moisture codes of the FWI System indicated drier fuels. Spatial variation in pre- and post-fire fuel load accounted for a substantial proportion of the variance in fuel loads. Average surface fuel consumption was a linear function of pre-fire fuel load. Average ground fuel combustion completeness could be predicted by the Buildup Index. Carbon release ranged between 0.36 and 1.00 kg C m-2. The flammability of ground fuel layers may explain the higher C release-rates seen for wildfires in comparison to prescribed burns. Drier moorland community types appear to be at greater risk of severe burns than blanket-bog communities.

  14. Vegetation structure and fire weather influence variation in burn severity and fuel consumption during peatland wildfires

    NASA Astrophysics Data System (ADS)

    Davies, G. M.; Domènech, R.; Gray, A.; Johnson, P. C. D.

    2016-01-01

    Temperate peatland wildfires are of significant environmental concern but information on their environmental effects is lacking. We assessed variation in burn severity and fuel consumption within and between wildfires that burnt British moorlands in 2011 and 2012. We adapted the composite burn index (pCBI) to provide semi-quantitative estimates of burn severity. Pre- and post-fire surface (shrubs and graminoids) and ground (litter, moss, duff) fuel loads associated with large wildfires were assessed using destructive sampling and analysed using a generalised linear mixed model (GLMM). Consumption during wildfires was compared with published estimates of consumption during prescribed burns. Burn severity and fuel consumption were related to fire weather, assessed using the Canadian Fire Weather Index System (FWI System), and pre-fire vegetation type. pCBI varied 1.6 fold between, and up to 1.7 fold within, wildfires. pCBI was higher where moisture codes of the FWI System indicated drier fuels. Spatial variation in pre- and post-fire fuel load accounted for a substantial proportion of the variance in fuel loads. Average surface fuel consumption was a linear function of pre-fire fuel load. Average ground fuel combustion completeness could be predicted by the Buildup Index. Carbon release ranged between 0.36 and 1.00 kg C m-2. The flammability of ground fuel layers may explain the higher C release-rates seen for wildfires in comparison to prescribed burns. Drier moorland community types appear to be at greater risk of severe burns than blanket-bog communities.

  15. Daily variations in the influence of noradrenaline on preferred ambient temperature of the Siberian hamster.

    PubMed

    Jefimow, Małgorzata; Wojciechowski, Michał; Tegowska, Eugenia

    2003-04-01

    Daily variations in sensitivity to noradrenaline (NA) and the activation of nonshivering thermogenesis (NST) are important for survival under a potentially wide range of environmental conditions. However, little is known regarding the ability of the Siberian hamster and other species to activate NST in the day and night when they may be subjected to marked variations in environmental temperature. In this study, the effects of acclimation temperature and time of day on the behavioral thermoregulatory response to NA injections in Siberian hamsters (Phodopus sungorus) was investigated. Hamsters were acclimated for 4 weeks to 23 degrees C and a L:D 12:12 h photoperiod. After acclimation, preferred ambient temperatures (PT(a)) in saline- and NA-injected animals were measured continuously in the temperature gradient system. NA (0.6 mg/kg; s.c.) was given every 4 h while PT(a) was monitored. After NA injections there was a rapid drop in PT(a), decreasing to approximately 15 degrees C within 10-20 min after each NA injection. Following 4 weeks of acclimation to 10 degrees C and a L:D 8:16 h photoperiod, the same hamsters were re-tested in the temperature gradient system. Cold acclimation led to an accentuation in the behavioral response with a decrease in PT(a) of approximately 10 degrees C. The maximal decrease in preferred ambient temperatures was recorded during the light phase of the day and during the second part of the night. Lowering of PT(a) after NA allows for rapid dissipation of the heat from NST. Overall, the behavioral response reflects the daily changes in brown adipose tissue sensitivity to NA and thus capacity for NST.

  16. Intraclonal Variations Among Streptococcus pneumoniae Isolates Influence the Likelihood of Invasive Disease in Children

    PubMed Central

    Browall, Sarah; Norman, Martin; Tångrot, Jeanette; Galanis, Ilias; Sjöström, Karin; Dagerhamn, Jessica; Hellberg, Christel; Pathak, Anuj; Spadafina, Tiziana; Sandgren, Andreas; Bättig, Patrick; Franzén, Oscar; Andersson, Björn; Örtqvist, Åke; Normark, Staffan; Henriques-Normark, Birgitta

    2014-01-01

    Background. Pneumococcal serotypes are represented by a varying number of clonal lineages with different genetic contents, potentially affecting invasiveness. However, genetic variation within the same genetic lineage may be larger than anticipated. Methods. A total of 715 invasive and carriage isolates from children in the same region and during the same period were compared using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Bacterial genome sequencing, functional assays, and in vivo virulence mice studies were performed. Results. Clonal types of the same serotype but also intraclonal variants within clonal complexes (CCs) showed differences in invasive-disease potential. CC138, a common CC, was divided into several PFGE patterns, partly explained by number, location, and type of temperate bacteriophages. Whole-genome sequencing of 4 CC138 isolates representing PFGE clones with different invasive-disease potentials revealed intraclonal sequence variations of the virulence-associated proteins pneumococcal surface protein A (PspA) and pneumococcal choline-binding protein C (PspC). A carrier isolate lacking PcpA exhibited decreased virulence in mice, and there was a differential binding of human factor H, depending on invasiveness. Conclusions. Pneumococcal clonal types but also intraclonal variants exhibited different invasive-disease potentials in children. Intraclonal variants, reflecting different prophage contents, showed differences in major surface antigens. This suggests ongoing immune selection, such as that due to PspC-mediated complement resistance through varied human factor H binding, that may affect invasiveness in children. PMID:24009156

  17. Quasi-decadal variability of the stratosphere: Influence of long-term solar ultraviolet variations

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Jirikowic, J. L.; Mccormack, J. P.

    1993-01-01

    A multiple regression statistical model is applied to investigate the existence of upper-stratospheric ozone, temperature, and zonal wind responses to long-term (solar cycle) changes in solar ultraviolet radiation using 11.5 years of reprocessed Nimbus-7 Solar Backscattered Ultraviolet (SBUV) data and 12.4 years of National Meteorological Center (NMC) data. A positive solar cycle variation of independently measured ozone and temperature occurs with maximum amplitude near the low-latitude stratopause. The seasonal solar regression coefficients near 1 mb for both ozone and temperature occur at low latitudes supporting a role for photochemical and radiative forcing in their origin. Zonal wind perturbations that correlate with long-term solar ultraviolet variations are a strong function of season and pressure level. Above approximately 2 mbar, the largest solar-correlated zonal wind enhancements occur at middle winter latitudes near the time of winter solstice in both hemispheres. The Northern Hemisphere December enhancement at 1 mb was especially large, 23 +/- 9 m/s from solar minimum to maximum during the last solar cycle. The derived ozone, temperature, and zonal wind increases with increasing solar ultraviolet flux near the stratopause are larger than predicted by models that consider primarily photochemical and radiative processes. The higher ozone and temperature response amplitudes at low latitudes may be due to modified ozone transport and adiabatic temperature changes induced by the dynamical response. If the midlatitude winter solstice wind enhancements are solar induced, their high amplitudes require a positive feedback due to wave-mean flow interaction such that the planetary wave drag on the flow is reduced under solar maximum conditions.

  18. Geographic variation in avian incubation periods and parental influences on embryonic temperature

    USGS Publications Warehouse

    Martin, T.E.; Auer, S.K.; Bassar, R.D.; Niklison, Alina M.; Lloyd, P.

    2007-01-01

    Theory predicts shorter embryonic periods in species with greater embryo mortality risk and smaller body size. Field studies of 80 passerine species on three continents yielded data that largely conflicted with theory; incubation (embryonic) periods were longer rather than shorter in smaller species, and egg (embryo) mortality risk explained some variation within regions, but did not explain larger differences in incubation periods among geographic regions. Incubation behavior of parents seems to explain these discrepancies. Bird embryos are effectively ectothermic and depend on warmth provided by parents sitting on the eggs to attain proper temperatures for development. Parents of smaller species, plus tropical and southern hemisphere species, commonly exhibited lower nest attentiveness (percent of time spent on the nest incubating) than larger and northern hemisphere species. Lower nest attentiveness produced cooler minimum and average embryonic temperatures that were correlated with longer incubation periods independent of nest predation risk or body size. We experimentally tested this correlation by swapping eggs of species with cool incubation temperatures with eggs of species with warm incubation temperatures and similar egg mass. Incubation periods changed (shortened or lengthened) as expected and verified the importance of egg temperature on development rate. Slower development resulting from cooler temperatures may simply be a cost imposed on embryos by parents and may not enhance offspring quality. At the same time, incubation periods of transferred eggs did not match host species and reflect intrinsic differences among species that may result from nest predation and other selection pressures. Thus, geographic variation in embryonic development may reflect more complex interactions than previously recognized. ?? 2007 The Author(s).

  19. Influence of altered low cloud parameterizations for seasonal variation of Arctic cloud amount on climate feedbacks

    NASA Astrophysics Data System (ADS)

    Kim, Yoojin; Choi, Yong-Sang; Kim, Baek-Min; Kim, Hyerim

    2015-12-01

    This study investigates the alteration of climate feedbacks due to overestimated wintertime low-level cloud amount bias over the Arctic region (60°N-90°N) in a climate model. The climate feedback was quantitatively examined through radiative kernels that are pre-calculated radiative responses of climate variables to doubling of carbon dioxide concentration in NCAR Community Atmosphere Model version 3 (CAM3). Climate models have various annual cycle of the Arctic cloud amount at the low-level particularly with large uncertainty in winter and CAM3 may tend to overestimate the Arctic low-level cloud. In this study, the seasonal variation of low-level cloud amount was modified by reducing the wintertime cloud amount by up to 35 %, and then compared with the original without seasonal variation. Thus, we investigate how that bias may affect climate feedbacks and the projections of future Arctic warming. The results show that the decrease in low-level cloud amount slightly affected the radiation budgets because of a small amount of incident solar insolation in winter, but considerably changed water vapor and temperature profiles. Consequently, the most distinctive was decreases in water vapor feedback and contribution of heat transport (by -0.20 and -0.55 W m-2 K-1, respectively) and increases in the lapse rate feedback and cloud feedback (by 0.13 and 0.58 W m-2 K-1, respectively) during winter in this model experiment. This study suggests that the change in Arctic cloud amount effectively reforms the contributions of individual climate feedbacks to Arctic climate system and leads to opposing effects on different feedbacks, which cancel out in the model.

  20. Influence of altered low cloud parameterizations for seasonal variation of Arctic cloud amount on climate feedbacks

    NASA Astrophysics Data System (ADS)

    Kim, Yoojin; Choi, Yong-Sang; Kim, Baek-Min; Kim, Hyerim

    2016-09-01

    This study investigates the alteration of climate feedbacks due to overestimated wintertime low-level cloud amount bias over the Arctic region (60°N-90°N) in a climate model. The climate feedback was quantitatively examined through radiative kernels that are pre-calculated radiative responses of climate variables to doubling of carbon dioxide concentration in NCAR Community Atmosphere Model version 3 (CAM3). Climate models have various annual cycle of the Arctic cloud amount at the low-level particularly with large uncertainty in winter and CAM3 may tend to overestimate the Arctic low-level cloud. In this study, the seasonal variation of low-level cloud amount was modified by reducing the wintertime cloud amount by up to 35 %, and then compared with the original without seasonal variation. Thus, we investigate how that bias may affect climate feedbacks and the projections of future Arctic warming. The results show that the decrease in low-level cloud amount slightly affected the radiation budgets because of a small amount of incident solar insolation in winter, but considerably changed water vapor and temperature profiles. Consequently, the most distinctive was decreases in water vapor feedback and contribution of heat transport (by -0.20 and -0.55 W m-2 K-1, respectively) and increases in the lapse rate feedback and cloud feedback (by 0.13 and 0.58 W m-2 K-1, respectively) during winter in this model experiment. This study suggests that the change in Arctic cloud amount effectively reforms the contributions of individual climate feedbacks to Arctic climate system and leads to opposing effects on different feedbacks, which cancel out in the model.

  1. Can the Tibetan Plateau snow cover influence the interannual variations of Eurasian heat wave frequency?

    NASA Astrophysics Data System (ADS)

    Wu, Zhiwei; Zhang, Peng; Chen, Hua; Li, Yun

    2016-06-01

    The Eurasian continent has experienced significant year-to-year variations of summer heat waves during the past decades. Several possible factors, such as ocean temperature, soil moisture, and changes in land use and greenhouse gases, have been identified in previous studies, but the mechanisms are still unclear. In this study, it is found that the Tibetan Plateau snow cover (TPSC) is closely linked to the interannual variations of summer heat waves over Eurasia. The TPSC variability explains more than 30 % of the total variances of heat wave variability in the southern Europe and northeastern Asia (SENA) region. A set of numerical experiments reveal that the reduced TPSC may induce a distinct teleconnection pattern across the Eurasian continent, with two anomalous high pressure centers in the upper troposphere over the SENA region, which may lead to a reduction of the cloud formation near the surface. The less cloud cover tends to increase the net shortwave radiation and favor a stronger surface sensible heat flux in the dry surface condition over the SENA region, resulting in a deeper, warmer and drier atmospheric boundary layer that would further inhibit the local cloud formation. Such a positive land-atmosphere feedback may dry the surface even further, heat the near-surface atmosphere and thereby intensify the local heat waves. The above dynamical processes also operate on interdecadal time scales. Given the reduction of the TPSC could become more pronounced with increasing levels of greenhouse gases in a warming climate, we infer that the TPSC may play an increasingly important role in shaping the summer heat waves over the SENA region in next decades.

  2. [Diel variations of hydrochemistry and influencing factors in a surface stream in subtropical karst area, SW China].

    PubMed

    Zhang, Tao; Pu, Jun-Bing; Yuan, Dao-Xian; Zhang, Cheng; He, Shi-Yi; Yu, Shi; Liu, Wen; Mo, Xue; Zhou, Jian-Chao; Yang, Hui; Tang, Wei

    2014-08-01

    In order to understand the diel variation and influencing factors of hydrochemistry in a surface creek fed by karst subterranean river in a subtropical area, where is located at Guancun Village, Daliang Township, Rong'an County of Guangxi Zhuang Autonomous Region, China, two monitoring sites were set simultaneously to launch Guancun subterranean river outlet (G1) and surface creek mouth (G2), respectively. Physical and hydrochemical parameters including pH, dissolved oxygen (DO), water temperature (T) and specific conductivity (Spc) were measured at 15-minute intervals and water samples for analyzing major ions such as Ca2+, HCO3- and NO3- as well as delta3C(DIC) were collected at 2-hour intervals. The results showed that: (1) G1 and G2 sites were both HCO3- Ca type water, however the two monitoring sites showed different diel variations of hydrogeochemical process; (2) The physical and hydrochemical parameters (T, DO, pH, Spc) and major ions (Ca2+, Mg2+, Na+, K+, HCO3-, SO4(2-), NO3-, Cl- in G1 site were basically stable, while the physical and hydrochemical parameters (T, DO, pH, Spc) and major ions (Ca2+, HCO3- and NO3-) in G2 site displayed regular diel variation during monitoring; (3) The dissolved inorganic carbon (DIC) and delta13C values in G2 monitoring site showed reverse characteristics in diurnal fluctuations, where DIC decreased in daylight and increased at night while the delta13C value increased in daylight and decreased at night, DIC also showed a negative correlation with the delta13C value (correlation coefficient is -0. 87, P < 0.01) in G2 site. These results indicated that photosynthesis and respiration of aquatic plants, water temperature and degassing jointly affected diurnal variation of hydrochemistry and controlled the cycling process of internal matter in this surface creek fed by karst subterranean river.

  3. Characterization of a Novel Antisense RNA in the Major Pilin Locus of Neisseria meningitidis Influencing Antigenic Variation

    PubMed Central

    Tan, Felicia Y. Y.; Wörmann, Mirka E.; Tang, Christoph M.

    2015-01-01

    ABSTRACT Expression of type four pili (Tfp) is essential for virulence in Neisseria meningitidis. Pili mediate adhesion, bacterial aggregation, and DNA uptake. In N. meningitidis, the major pilin subunit is encoded by the pilE gene. In some strains, PilE is subject to phase and antigenic variation, which can alter Tfp properties and together offer a possible mechanism of immune escape. Pilin expression and antigenic variation can be modulated in response to environmental cues; however, the precise mechanisms of such regulation remain unclear. We identified a promoter in the pilE locus, 3′ of the pilE coding sequence, on the antisense (AS) strand which is conserved in meningococci. We show that this promoter directs transcription of an AS RNA that is expressed during specific growth phases and in response to salt stress. Furthermore, we demonstrate that the transcript encompasses sequences complementary to the entire pilE coding sequence and 5′ untranslated region. AS RNAs can regulate the gene on the sense strand by altering transcript stability or translation. However, by using Northern blotting, quantitative reverse transcription-PCR (RT-PCR), and Western blotting, we found no significant AS RNA-dependent changes in pilE transcript or protein level. Instead, our data indicate that the AS RNA influences pilin antigenic variation. This work provides further insights into the complex regulation of pilin expression and variation in pathogenic Neisseria. IMPORTANCE Pathogenic Neisseria spp. express type four pili (Tfp) which are important for adhesion, aggregation and transformation. Some strains of N. meningitidis are able to vary the sequence of the major subunit (PilE) of the Tfp. The mechanisms underlying this variation are not fully defined, but the process requires several noncoding elements that are found adjacent to the pilE gene. In this work, we identified a cis-encoded RNA antisense to pilE in N. meningitidis. By using Northern blotting and RT

  4. Vertical variations in the influence of the amount effect: South American Summer Monsoon Region

    NASA Astrophysics Data System (ADS)

    Samuels-Crow, K. E.; Galewsky, J.; Worden, J. R.

    2014-12-01

    Recent theoretical studies have shown that convective recycling of atmospheric water vapor gives rise to the isotope "amount effect" in which d values are lower than predicted by simple Rayleigh distillation processes (i.e. (DdD = dDvapor ­- dDRayleigh < 0‰). Several studies have linked isotopes in precipitation [e.g. Vimeux et al., 2009] and atmospheric water vapor [e.g. Samuels-Crow et al., 2014] in the tropical Andes to upwind convection associated with the South American Summer Monsoon (SASM). The vertical structure of this convective influence, however, remains unknown. Understanding the vertical structure of the amount effect over South America is essential for improving theoretical constraints and developing better models of the influence of the SASM on southern hemisphere humidity. Additionally, evaluating the vertical and lateral extent of the SASM's convective influence can provide important constraints for interpreting paleoclimate proxies in the region. We use data from the Tropospheric Emission Spectrometer (TES) to examine the vertical structure of the amount effect associated with the SASM and relate these results to regional convective precipitation and local subcloud equivalent potential temperature. Preliminary results show that DdD is below 0‰ from the boundary layer through the mid-troposphere over tropical South America during austral summer, and meridional averages show that convective precipitation is highest over these areas where DdD < 0‰ extends higher in the atmosphere. We hypothesize that the depth of convection in the monsoon region controls the vertical structure of DdD, which should also be coherently linked to local equivalent potential temperature. References Vimeux et al. (2009), Palaeogeogr Palaeocl, 281(3-4), 229-241, doi:10.1016/j.palaeo.2008.03.054. Samuels-Crow et al. (2014), J Geophys Res-Atmos, doi:10.1002/(ISSN)2169-8996.

  5. Large-scale spatial variation in parasite communities influenced by anthropogenic factors.

    PubMed

    Altman, Irit; Byers, James E

    2014-07-01

    Parasites are integral members of natural communities, but large-scale determinants of their abundance and diversity, including the importance of biotic and abiotic factors, both natural and anthropogenic, are often not well understood. Here, we examine which factors best predict larval trematode communities in the mudsnail host Ilyanassa obsoleta across a regional landscape. At 15 salt marsh sites spanning 200 km, we quantified the diversity of trematodes and the prevalence (i.e., proportion) of infected hosts and sampled a broad array of potential parasite predictors including abundance of intermediate and definitive hosts, habitat, nutrients, metals, roads, and sediment characteristics. We identified the set of best performing models to explain variability associated with five metrics of trematode prevalence and diversity using an information-theoretic approach. Results indicate that several anthropogenic factors associate with this trematode community and that the direction of their influence differs. Road density around sites was a strong negative predictor of all trematode prevalence and species richness metrics. Nitrogen, another human influenced variable, was a strong positive predictor for the most abundant trematode species in the system. In addition, the abundance of definitive fish hosts was a positive predictor in several models, confirming the importance of this direct biological link to parasites. Other influential variables included sediment composition and heavy metals (arsenic, copper, lead, and zinc). We discuss possible direct and indirect mechanisms to explain these findings including that anthropogenic factors may be directly influencing free-living stages of trematodes, or be acting as proxies of hard-to-measure hosts. PMID:25163120

  6. The influence of climatically-driven surface loading variations on continental strain and seismicity

    NASA Astrophysics Data System (ADS)

    Craig, Tim; Calais, Eric; Fleitout, Luce; Bollinger, Laurent; Scotti, Oona

    2016-04-01

    In slowly deforming regions of plate interiors, secondary sources of stress and strain can result in transient deformation rates comparable to, or greater than, the background tectonic rates. Highly variable in space and time, these transients have the potential to influence the spatio-temporal distribution of seismicity, interfering with any background tectonic effects to either promote or inhibit the failure of pre-existing faults, and potentially leading to a clustered, or 'pulse-like', seismic history. Here, we investigate the ways in which the large-scale deformation field resulting from climatically-controlled changes in surface ice mass over the Pleistocene and Holocene may have influenced not only the seismicity of glaciated regions, but also the wider seismicity around the ice periphery. We first use a set of geodynamic models to demonstrate that a major pulse of seismic activity occurring in Fennoscandia, coincident with the time of end-glaciation, occurred in a setting where the contemporaneous horizontal strain-rate resulting from the changing ice mass, was extensional - opposite to the reverse sense of coseismic displacement accommodated on these faults. Therefore, faulting did not release extensional elastic strain that was building up at the time of failure, but compressional elastic strain that had accumulated in the lithosphere on timescales longer than the glacial cycle, illustrating the potential for a non-tectonic trigger to tap in to the background tectonic stress-state. We then move on to investigate the more distal influence that changing ice (and ocean) volumes may have had on the evolving strain field across intraplate Europe, how this is reflected in the seismicity across intraplate Europe, and what impact this might have on the paleoseismic record.

  7. Large-scale spatial variation in parasite communities influenced by anthropogenic factors.

    PubMed

    Altman, Irit; Byers, James E

    2014-07-01

    Parasites are integral members of natural communities, but large-scale determinants of their abundance and diversity, including the importance of biotic and abiotic factors, both natural and anthropogenic, are often not well understood. Here, we examine which factors best predict larval trematode communities in the mudsnail host Ilyanassa obsoleta across a regional landscape. At 15 salt marsh sites spanning 200 km, we quantified the diversity of trematodes and the prevalence (i.e., proportion) of infected hosts and sampled a broad array of potential parasite predictors including abundance of intermediate and definitive hosts, habitat, nutrients, metals, roads, and sediment characteristics. We identified the set of best performing models to explain variability associated with five metrics of trematode prevalence and diversity using an information-theoretic approach. Results indicate that several anthropogenic factors associate with this trematode community and that the direction of their influence differs. Road density around sites was a strong negative predictor of all trematode prevalence and species richness metrics. Nitrogen, another human influenced variable, was a strong positive predictor for the most abundant trematode species in the system. In addition, the abundance of definitive fish hosts was a positive predictor in several models, confirming the importance of this direct biological link to parasites. Other influential variables included sediment composition and heavy metals (arsenic, copper, lead, and zinc). We discuss possible direct and indirect mechanisms to explain these findings including that anthropogenic factors may be directly influencing free-living stages of trematodes, or be acting as proxies of hard-to-measure hosts.

  8. The influences of fluorine and process variations on polysilicon film stress and MOSFET hot carrier effects

    NASA Technical Reports Server (NTRS)

    Lowry, Lynn E.; Macwilliams, Kenneth P.; Isaac, Mary

    1991-01-01

    The use of fluorinated gate oxides may provide an improvement in nMOSFET reliability by enhancing hot carrier resistance. In order to clarify the mechanisms by which polysilicon processing and fluorination influence the oxide behavior, a matrix of nMOSFET structures was prepared using various processing, doping, and implantation strategies. These structures were evaluated for crystalline morphology and chemical element distribution. Mechanical stress measurements were taken on the polysilicon films from room temperature to cryogenic temperature. These examinations showed that fluorination of a structure with randomly oriented polysilicon can reduce residual mechanical stress and improve hot carrier resistance at room temperature.

  9. Physical fitness of children and adolescents in the United States: status and secular change.

    PubMed

    Malina, Robert M

    2007-01-01

    The physical fitness of school-age children in the United States is considered from two perspectives--status and secular change. This chapter principally examines health-related fitness, including the BMI, though performance-related fitness is briefly considered. Concepts of reference data and standards and factors that may influence secular change are initially discussed. National data on the physical fitness status of school children in the continental United States are limited to the 1980s. Ethnic variation in physical fitness is not considered except for the prevalence of overweight and obesity. More recent physical fitness data, including examination of ethnic variation, are based on several statewide and more local surveys. Although results vary by test, the majority of American school children meet or exceed criterion-referenced standards, although sex differences are not consistent. Poor morphological fitness manifest in obesity is an exception. The prevalence of overweight and obesity has increased since the early 1980s. Secular data for specific fitness items are less extensive. Regression analyses suggest a recent decline in maximal aerobic power in girls, but fairly stable levels between the 1930s and today in boys. However, the highest values for boys occur in the 1960s and 1970s and more recent values are somewhat lower. The general trend may be consistent with the decline since the 1980s in aerobic performance assessed with the 20 m shuttle run. These trends highlight the need for updated national physical fitness data for American youth.

  10. fits2hdf: FITS to HDFITS conversion

    NASA Astrophysics Data System (ADS)

    Price, D. C.; Barsdell, B. R.; Greenhill, L. J.

    2015-05-01

    fits2hdf ports FITS files to Hierarchical Data Format (HDF5) files in the HDFITS format. HDFITS allows faster reading of data, higher compression ratios, and higher throughput. HDFITS formatted data can be presented transparently as an in-memory FITS equivalent by changing the import lines in Python-based FITS utilities. fits2hdf includes a utility to port MeasurementSets (MS) to HDF5 files.

  11. Metabolic Flux and Fitness

    PubMed Central

    Dykhuizen, Daniel E.; Dean, Antony M.; Hartl, Daniel L.

    1987-01-01

    Studies of Escherichia coli under competition for lactose in chemostat cultures have been used to determine the selective effects of variation in the level of the β-galactoside permease and the β-galactosidase enzyme. The results determine the adaptive topography of these gene products relative to growth in limiting lactose and enable predictions concerning the selective effects of genetic variants found in natural populations. In the terms of metabolic control theory, the β-galactosidase enzyme at wild-type-induced levels has a small control coefficient with respect to fitness (C = 0.018), and hence genetic variants resulting in minor changes in enzyme activity have disproportionately small effects on fitness. However, the apparent control coefficient of the β-galactoside permease at wild-type-induced levels is large (C = 0.551), and hence even minor changes in activity affect fitness. Therefore, we predict that genetic polymorphisms in the lacZ gene are subject to less effective selection in natural populations than are those in the lacY gene. The β-galactoside permease is also less efficient than might be expected, and possible forces resulting in selection for an intermediate optimum level of permease activity are considered. The selective forces that maintain the lactose operon in a regulated state in natural populations are also discussed. PMID:3104135

  12. C-reactive protein levels are influenced by common IL-1 gene variations.

    PubMed

    Berger, Peter; McConnell, Joseph P; Nunn, Martha; Kornman, Kenneth S; Sorrell, Julian; Stephenson, Katherine; Duff, Gordon W

    2002-02-21

    Elevated markers of systemic inflammation are associated with the development of acute coronary syndromes, but there is no current explanation for increased inflammation in overtly healthy individuals. The influence of genetic control of the inflammatory response on the observed variability is unknown. We studied the frequency of four polymorphisms in interleukin (IL) 1 genes, known to modulate inflammation, in 454 individuals undergoing coronary angiography and analysed their influence on plasma C-reactive protein (CRP) and fibrinogen levels. Females and smokers had higher levels of CRP than males (Pi = 0.001) and non-smokers (Pi = 0.001). Patients with genotype 2.2 for the IL-1B(+3954) polymorphism had twice the median CRP levels of patients who were genotype 1.1 (4.33 vs 2.01 mg/l; P = 0.001). Patients with genotype 1.2 or 2.2 at the IL-1A(+4845) polymorphism also had higher median CRP (2.92 vs 2.05 mg/l, Pi = 0.023). In multivariate analyses, CRP levels remained significantly associated with IL-1 polymorphisms after adjustment for smoking, gender and age. Fibrinogen levels had similar associations with the IL-1 genotypes. These data indicate that IL-1 gene polymorphisms known to affect the inflammatory response are highly related to plasma levels of CRP and fibrinogen in patients referred for coronary angiography.

  13. The influence of diurnal temperature variation on degree-day accumulation and insect life history.

    PubMed

    Chen, Shi; Fleischer, Shelby J; Saunders, Michael C; Thomas, Matthew B

    2015-01-01

    Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatures can be derived from the daily maximum and minimum temperatures. However, the converse is not true and environments with the same mean temperature can exhibit very different diurnal temperate ranges. Here we apply a degree-day model for development of the grape berry moth (Paralobesia viteana, a significant vineyard pest in the northeastern USA) to investigate how different diurnal temperature range conditions can influence degree-day accumulation and, hence, insect life history. We first consider changes in diurnal temperature range independent of changes in mean temperatures. We then investigate grape berry moth life history under potential climate change conditions, increasing mean temperature via variable patterns of change to diurnal temperature range. We predict that diurnal temperature range change can substantially alter insect life history. Altering diurnal temperature range independent of the mean temperature can affect development rate and voltinism, with the magnitude of the effects dependent on whether changes occur to the daily minimum temperature (Tmin), daily maximum temperature (Tmax), or both. Allowing for an increase in mean temperature produces more marked effects on life history but, again, the patterns and magnitude depend on the nature of the change to diurnal temperature range together with the starting conditions in the local environment. The study highlights the importance of characterizing the influence of diurnal temperature range in addition to mean temperature alone.

  14. The Influence of Diurnal Temperature Variation on Degree-Day Accumulation and Insect Life History

    PubMed Central

    Chen, Shi; Fleischer, Shelby J.; Saunders, Michael C.; Thomas, Matthew B.

    2015-01-01

    Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatures can be derived from the daily maximum and minimum temperatures. However, the converse is not true and environments with the same mean temperature can exhibit very different diurnal temperate ranges. Here we apply a degree-day model for development of the grape berry moth (Paralobesia viteana, a significant vineyard pest in the northeastern USA) to investigate how different diurnal temperature range conditions can influence degree-day accumulation and, hence, insect life history. We first consider changes in diurnal temperature range independent of changes in mean temperatures. We then investigate grape berry moth life history under potential climate change conditions, increasing mean temperature via variable patterns of change to diurnal temperature range. We predict that diurnal temperature range change can substantially alter insect life history. Altering diurnal temperature range independent of the mean temperature can affect development rate and voltinism, with the magnitude of the effects dependent on whether changes occur to the daily minimum temperature (Tmin), daily maximum temperature (Tmax), or both. Allowing for an increase in mean temperature produces more marked effects on life history but, again, the patterns and magnitude depend on the nature of the change to diurnal temperature range together with the starting conditions in the local environment. The study highlights the importance of characterizing the influence of diurnal temperature range in addition to mean temperature alone. PMID:25790195

  15. [Influences of fertilization and seasonal variation on microbial community in a Chinese mollisol].

    PubMed

    Bai, Zhen; He, Hong-Bo; Xie, Hong-Tu; Zhang, Ming; Zhang, Xu-Dong

    2008-11-01

    Fertilization and seasonal variation play very important roles in affecting microbial structure and activity, as a result, leading to the significant evolution of soil fertility. The effect of manure (MCK) and combined application of chemical fertilizers (NPK) on soil microbial biomass and structure were studied by measuring soil microbial biomass carbon (nitrogen) and phospholipid fatty acid (PLFA) in different microbial communities, with the nil-fertilization (CK) and fallow as controls. Results show the manure application significantly improves the soil nutrient contents and the amounts of Cmic and PLFA of different microbial communities. The amounts of fungal PLFA (8.40 nmol x g(-1)) and Cmic (322.5 mg x kg(-1)) and Nmic (57.9 mg x kg(-1)) are significantly higher than those of CK (5.4 nmo x g(-1), 152.6 mg x kg(-1), 32.1 mg x kg(-1), respectively) or NPK (3.5 nmol x g(-1), 144.3 mg x kg(-1), 30.7 mg x kg(-1), respectively). And the contents of Cmic, Nmic and PLFA of different microbial groups in NPK are lower than those in CK. Correlation analyses show the soil nutrient contents are significantly positively correlated with Cmic, different microbial PLFA contents and G(-)/total bacteria ratios, while negatively correlated with C+/G(-) bacteria ratio (p < 0.05). The principle component analysis of PLFA shows the microbial structures in different treatments and sampling dates are significantly different. Seasonal changes are also found to cause great fluctuations in soil basic properties, and microbial community structure in arable soils and fallow respectively cluster strictly together by sampling dates. The amount of Cmic is highest on April 11 (295.6 mg x kg(-1)), while Nmic (49.3 mg x kg(-1)) and PLFA contents are highest in summer (July-August); the lowest amounts of Cmic (184.2 mg x kg(-1)), Nmic (30.63 mg x kg(-1)) and PLFA exist on May 31. Fertilization and seasonal variations significantly affect soil fertility, microbial structure and activity. PMID

  16. Influence of the corn resistance gene Mv on the fitness of Peregrinus maidis (Hemiptera: Delphacidae) and on the transmission of maize mosaic virus (Rhabdoviridae: Nucleorhabdovirus).

    PubMed

    Higashi, C H V; Brewbaker, J L; Bressan, A

    2013-08-01

    Crops that are resistant to pests and pathogens are cost-effective for the management of pests and diseases. A corn (Zea mays L.) breeding program conducted in Hawaii has identified a source of heritable resistance to maize mosaic virus (MMV) (Rhabdoviridae: Nucleorhabdovirus). This resistance is controlled by the gene Mv, which has been shown to have a codominant action. To date, no studies have examined whether the resistance associated with this gene affects only MMV or whether it also affects the insect vector, the corn planthopper Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae). Here, we examined the life history of the corn planthopper and its ability to transmit MMV on near isogenic lines that were homozygous dominant (Mv/Mv), homozygous recessive (mv/mv), or heterozygous (Mv/mv) for the gene. A field trial was also conducted to study the colonization of the corn plants with different genotypes by the planthopper. Although field observations revealed slightly lower densities ofplanthoppers on corn with the genotype Mv/Mv than on the inbreds with the genotype mv/mv and their hybrids with the genotype Mv/mv, laboratory assays showed no effects of the gene on planthopper development, longevity, or fecundity. In the field, the corn lines Mv/Mv had a lower incidence of MMV-infected plants. However, in the greenhouse, the transmission of MMV to corn seedlings did not differ across the near isogenic lines, although the corn lines Mv/Mv showed a delayed onset of symptoms compared with the corn lines mv/mv and Mv/mv. The acquisition of MMV by corn planthoppers on the corn genotypes Mv/Mv and Mv/mv averaged 0.2, whereas the acquisition on the corn genotypes mv/mv averaged > 0.3. Our results show that the Mv gene does not influence the fitness of the planthopper vector, suggesting that it may confer resistance by other means, possibly by limiting virus replication or movement within the host plant.

  17. Sources of Variation Influencing Concordance between Functional MRI and Direct Cortical Stimulation in Brain Tumor Surgery

    PubMed Central

    Morrison, Melanie A.; Tam, Fred; Garavaglia, Marco M.; Hare, Gregory M. T.; Cusimano, Michael D.; Schweizer, Tom A.; Das, Sunit; Graham, Simon J.

    2016-01-01

    Object: Preoperative functional magnetic resonance imaging (fMRI) remains a promising method to aid in the surgical management of patients diagnosed with brain tumors. For patients that are candidates for awake craniotomies, surgical decisions can potentially be improved by fMRI but this depends on the level of concordance between preoperative brain maps and the maps provided by the gold standard intraoperative method, direct cortical stimulation (DCS). There have been numerous studies of the concordance between fMRI and DCS using sensitivity and specificity measures, however the results are variable across studies and the key factors influencing variability are not well understood. Thus, the present work addresses the influence of technical factors on fMRI and DCS concordance. Methods: Motor and language mapping data were collected for a group of glioma patients (n = 14) who underwent both preoperative fMRI and intraoperative DCS in an awake craniotomy procedure for tumor removal. Normative fMRI data were also acquired in a healthy control group (n = 12). The fMRI and DCS mapping data were co-registered; true positive (TP), true negative (TN), false positive (FP), and false negative (FN) occurrences were tabulated over the exposed brain surface. Sensitivity and specificity were measured for the total group, and for the motor and language sub-groups. The influence of grid placement, fMRI statistical thresholding, and task standardization were assessed. Correlations between proportions of agreement and error were also carefully scrutinized to evaluate concordance in more detail. Results: Concordance was significantly better for motor vs. language mapping. There was an inverse relationship between TP and TN with increasing statistical threshold, and FP dominated the total error. Sensitivity and specificity were reduced when tasks were not standardized across fMRI and DCS. Conclusions: Although the agreement between fMRI and DCS is good, variability is introduced by

  18. Chromosome 7p11.2 (EGFR) variation influences glioma risk

    PubMed Central

    Sanson, Marc; Hosking, Fay J.; Shete, Sanjay; Zelenika, Diana; Dobbins, Sara E.; Ma, Yussanne; Enciso-Mora, Victor; Idbaih, Ahmed; Delattre, Jean-Yves; Hoang-Xuan, Khe; Marie, Yannick; Boisselier, Blandine; Carpentier, Catherine; Wang, Xiao-Wei; Di Stefano, Anna Luisa; Labussière, Marianne; Gousias, Konstantinos; Schramm, Johannes; Boland, Anne; Lechner, Doris; Gut, Ivo; Armstrong, Georgina; Liu, Yanhong; Yu, Robert; Lau, Ching; Di Bernardo, Maria Chiara; Robertson, Lindsay B.; Muir, Kenneth; Hepworth, Sarah; Swerdlow, Anthony; Schoemaker, Minouk J; Wichmann, H.-Erich; Müller, Martina; Schreiber, Stefan; Franke, Andre; Moebus, Susanne; Eisele, Lewin; Försti, Asta; Hemminki, Kari; Lathrop, Mark; Bondy, Melissa; Houlston, Richard S.; Simon, Matthias

    2011-01-01

    While gliomas are the most common primary brain tumors, their etiology is largely unknown. To identify novel risk loci for glioma, we conducted genome-wide association (GWA) analysis of two case–control series from France and Germany (2269 cases and 2500 controls). Pooling these data with previously reported UK and US GWA studies provided data on 4147 glioma cases and 7435 controls genotyped for 424 460 common tagging single-nucleotide polymorphisms. Using these data, we demonstrate two statistically independent associations between glioma and rs11979158 and rs2252586, at 7p11.2 which encompasses the EGFR gene (population-corrected statistics, Pc = 7.72 × 10−8 and 2.09 × 10−8, respectively). Both associations were independent of tumor subtype, and were independent of EGFR amplification, p16INK4a deletion and IDH1 mutation status in tumors; compatible with driver effects of the variants on glioma development. These findings show that variation in 7p11.2 is a determinant of inherited glioma risk. PMID:21531791

  19. Common variations in BARD1 influence susceptibility to high-risk neuroblastoma

    PubMed Central

    Capasso, Mario; Hou, Cuiping; Asgharzadeh, Shahab; Glessner, Joseph T.; Attiyeh, Edward F.; Mosse, Yael P.; Kim, Cecilia; Diskin, Sharon J.; Cole, Kristina A.; Bosse, Kristopher; Diamond, Maura; Laudenslager, Marci; Winter, Cynthia; Bradfield, Jonathan P.; Scott, Richard H.; Jagannathan, Jayanti; Garris, Maria; McConville, Carmel; London, Wendy B.; Seeger, Robert C.; Grant, Struan F. A.; Li, Hongzhe; Rahman, Nazneen; Rappaport, Eric

    2009-01-01

    We conducted a SNP-based genome-wide association study (GWAS) focused on the high-risk subset of neuroblastoma1. As our previous unbiased GWAS showed strong association of common 6p22 SNP alleles with aggressive neuroblastoma2, we now restricted our analysis to 397 high-risk cases compared to 2,043 controls. We detected new significant association of six SNPs at 2q35 within the BARD1 gene locus (Pallelic = 2.35×10−9 − 2.25×10−8). Each SNP association was confirmed in a second series of 189 high-risk cases and 1,178 controls (Pallelic = 7.90×10−7 − 2.77×10−4). The two most significant SNPs (rs6435862, rs3768716) were also tested in two additional independent high-risk neuroblastoma case series, yielding combined allelic odds-ratios of 1.68 each (P = 8.65×10−18 and 2.74×10−16, respectively). Significant association was also found with known BARD1 nsSNPs. These data show that common variation in BARD1 contributes to the etiology of the aggressive and most clinically relevant subset of human neuroblastoma. PMID:19412175

  20. Influence of isentropic transport on seasonal ozone variations in the lower stratosphere and subtropical upper troposphere

    NASA Technical Reports Server (NTRS)

    Jing, P.; Cunnold, D. M.; Yang, E.-S.; Wang, H.-J.

    2005-01-01

    The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment 11 ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is approx.118 +/- 61 x 10(exp9)kg/yr globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer.

  1. Regional Variations of Public Perception on Contaminated Industrial Sites in China and Its Influencing Factors

    PubMed Central

    Li, Xiaonuo; Jiao, Wentao; Xiao, Rongbo; Chen, Weiping; Bai, Yanying

    2016-01-01

    Public involvement is critical in sustainable contaminated site management. It is important for China to improve public knowledge and participation, foster dialogue between urban managers and laypeople, and accelerate the remediation and redevelopment processes in contaminated site management. In this study, we collected 1812 questionnaires from nine cities around China through face-to-face interviews and statistically analyzed the perception of residents concerning contaminated sites. The results show that respondents’ concern about soil pollution was lower than for other environmental issues and their knowledge of soil contamination was limited. The risks posed by contaminated industrial sites were well recognized by respondents, but they were unsatisfied with the performance of local agencies regarding information disclosure, publicity and education and public participation. Respondents believed that local governments and polluters should take the primary responsibility for contaminated site remediation. Most of them were unwilling to pay for contaminated site remediation and preferred recreational or public service redevelopment. Moreover, our research indicated that public perception varied among different cities. This variation was mainly determined by implementations of policy instruments and additionally affected by remediation technology, pollutant type, regional policy response and living distance. PMID:27070632

  2. Regional Variations of Public Perception on Contaminated Industrial Sites in China and Its Influencing Factors.

    PubMed

    Li, Xiaonuo; Jiao, Wentao; Xiao, Rongbo; Chen, Weiping; Bai, Yanying

    2016-04-01

    Public involvement is critical in sustainable contaminated site management. It is important for China to improve public knowledge and participation, foster dialogue between urban managers and laypeople, and accelerate the remediation and redevelopment processes in contaminated site management. In this study, we collected 1812 questionnaires from nine cities around China through face-to-face interviews and statistically analyzed the perception of residents concerning contaminated sites. The results show that respondents' concern about soil pollution was lower than for other environmental issues and their knowledge of soil contamination was limited. The risks posed by contaminated industrial sites were well recognized by respondents, but they were unsatisfied with the performance of local agencies regarding information disclosure, publicity and education and public participation. Respondents believed that local governments and polluters should take the primary responsibility for contaminated site remediation. Most of them were unwilling to pay for contaminated site remediation and preferred recreational or public service redevelopment. Moreover, our research indicated that public perception varied among different cities. This variation was mainly determined by implementations of policy instruments and additionally affected by remediation technology, pollutant type, regional policy response and living distance. PMID:27070632

  3. The community structure of macroscopic basidiomycetes (Fungi) in Brazilian mangroves influenced by temporal and spatial variations.

    PubMed

    Nogueira-Melo, Georgea Santos; Santos, Paulo Jorge Parreira; Gibertoni, Tatiana Baptista

    2014-12-01

    Mangroves are transitional ecosystems between terrestrial and marine environments, and are dis- tinguished by a high abundance of animals, plants, and fungi. Although macrofungi occur in different types of habitat, including mangroves, little is known about their community structure and dynamic. Therefore the aim of this study was to analyze the diversity of macrofungi in a number of Brazilian mangroves, and the relation- ship between such diversity, precipitation and area of collection. A total of 32 field trips were undertaken from 2009 to 2010, and macrofungi were studied in four 250 x 40 m transects: Timbó and Santa Cruz Channel on the Northern coast, and Maracaipe and Ariquindá on the Southern coast. All basidiomata found along the transects were placed in paper bags, air-dried and identified using existing literature. It was found that Northern areas predominantly featured Avicennia schaueriana mangroves, while Rhizophora mangle dominated in Southern transects. A total of 275 specimens were collected, and 33 species, 28 genera, 14 families and six orders were represented. Overall abundance and species richness did not vary significantly among areas, but varied according to time, being higher during the rainy season. Subtle differences in composition were observed over time and between areas, probably due to variations in plant species occurrence. Further studies with collections during months of greater precipitation in transects dominated by different mangrove species of the same ecosystem are suggested to assess the overall diversity of mycobiota in these ecosystems. PMID:25720189

  4. Influence of Chemical Composition Variations on Densification During the Sintering of MOX Materials

    NASA Astrophysics Data System (ADS)

    Vaudez, S.; Marlot, C.; Lechelle, J.

    2016-06-01

    The mixed uranium-plutonium oxide (MOX) fabrication process is based on the preparation of UO2 and PuO2 powders. The mixture is pelletized before being sintered at 1973 K (1700 °C) in a reducing atmosphere of Ar/4pctH2/H2O. This paper shows how the densification of MOX fuel is affected during sintering by the moisture content of the gas, the plutonium content of the fuel, and the carbon impurity content in the raw materials. MOX densification can be monitored through dilatometric measurements and gas releases can be continuously analyzed during sintering in terms of their quantity and quality. Variations in the oxygen content in the fuel can be continuously recorded by coupling the dilatometer furnace with an oxygen measurement at the gas outlet. Any carbon-bearing species released, such as CO, can be also linked to densification phenomena when a gas chromatograph is installed at the outlet of the dilatometer. Recommendations on the choice of sintering atmosphere that best optimizes the fuel characteristics have been given on the basis of the results reported in this paper.

  5. Regional Variations of Public Perception on Contaminated Industrial Sites in China and Its Influencing Factors.

    PubMed

    Li, Xiaonuo; Jiao, Wentao; Xiao, Rongbo; Chen, Weiping; Bai, Yanying

    2016-04-08

    Public involvement is critical in sustainable contaminated site management. It is important for China to improve public knowledge and participation, foster dialogue between urban managers and laypeople, and accelerate the remediation and redevelopment processes in contaminated site management. In this study, we collected 1812 questionnaires from nine cities around China through face-to-face interviews and statistically analyzed the perception of residents concerning contaminated sites. The results show that respondents' concern about soil pollution was lower than for other environmental issues and their knowledge of soil contamination was limited. The risks posed by contaminated industrial sites were well recognized by respondents, but they were unsatisfied with the performance of local agencies regarding information disclosure, publicity and education and public participation. Respondents believed that local governments and polluters should take the primary responsibility for contaminated site remediation. Most of them were unwilling to pay for contaminated site remediation and preferred recreational or public service redevelopment. Moreover, our research indicated that public perception varied among different cities. This variation was mainly determined by implementations of policy instruments and additionally affected by remediation technology, pollutant type, regional policy response and living distance.

  6. The community structure of macroscopic basidiomycetes (Fungi) in Brazilian mangroves influenced by temporal and spatial variations.

    PubMed

    Nogueira-Melo, Georgea Santos; Santos, Paulo Jorge Parreira; Gibertoni, Tatiana Baptista

    2014-12-01

    Mangroves are transitional ecosystems between terrestrial and marine environments, and are dis- tinguished by a high abundance of animals, plants, and fungi. Although macrofungi occur in different types of habitat, including mangroves, little is known about their community structure and dynamic. Therefore the aim of this study was to analyze the diversity of macrofungi in a number of Brazilian mangroves, and the relation- ship between such diversity, precipitation and area of collection. A total of 32 field trips were undertaken from 2009 to 2010, and macrofungi were studied in four 250 x 40 m transects: Timbó and Santa Cruz Channel on the Northern coast, and Maracaipe and Ariquindá on the Southern coast. All basidiomata found along the transects were placed in paper bags, air-dried and identified using existing literature. It was found that Northern areas predominantly featured Avicennia schaueriana mangroves, while Rhizophora mangle dominated in Southern transects. A total of 275 specimens were collected, and 33 species, 28 genera, 14 families and six orders were represented. Overall abundance and species richness did not vary significantly among areas, but varied according to time, being higher during the rainy season. Subtle differences in composition were observed over time and between areas, probably due to variations in plant species occurrence. Further studies with collections during months of greater precipitation in transects dominated by different mangrove species of the same ecosystem are suggested to assess the overall diversity of mycobiota in these ecosystems.

  7. Novel candidate genes influencing natural variation in potato tuber cold sweetening identified by comparative proteomics and association mapping

    PubMed Central

    2013-01-01

    Background Higher plants evolved various strategies to adapt to chilling conditions. Among other transcriptional and metabolic responses to cold temperatures plants accumulate a range of solutes including sugars. The accumulation of the reducing sugars glucose and fructose in mature potato tubers during exposure to cold temperatures is referred to as cold induced sweetening (CIS). The molecular basis of CIS in potato tubers is of interest not only in basic research on plant adaptation to environmental stress but also in applied research, since high amounts of reducing sugars affect negatively the quality of processed food products such as potato chips. CIS-tolerance varies considerably among potato cultivars. Our objective was to identify by an unbiased approach genes and cellular processes influencing natural variation of tuber sugar content before and during cold storage in potato cultivars used in breeding programs. We compared by two-dimensional polyacrylamide gel electrophoresis the tuber proteomes of cultivars highly diverse for CIS. DNA polymorphisms in genomic sequences encoding differentially expressed proteins were tested for association with tuber starch content, starch yield and processing quality. Results Pronounced natural variation of CIS was detected in tubers of a population of 40 tetraploid potato cultivars. Significant differences in protein expression were detected between CIS-tolerant and CIS-sensitive cultivars before the onset as well as during cold storage. Identifiable differential proteins corresponded to protease inhibitors, patatins, heat shock proteins, lipoxygenase, phospholipase A1 and leucine aminopeptidase (Lap). Association mapping based on single nucleotide polymorphisms supported a role of Lap in the natural variation of the quantitative traits tuber starch and sugar content. Conclusions The combination of comparative proteomics and association genetics led to the discovery of novel candidate genes for influencing the natural

  8. Variation in winter snowpack depth and duration influences summer soil respiration in a subalpine meadow

    NASA Astrophysics Data System (ADS)

    Arnold, C. L.; Ghezzehei, T. A.; Berhe, A. A.

    2012-12-01

    Subalpine meadows in the Sierra Nevada rely on the depth and duration of the winter snowpack to supply ample water to restore the water table in the meadow during the spring snowmelt. This study examines the role that interannual variability in the winter snowpack plays in the overall rate of summer soil respiration along a hydrologic gradient in a subalpine meadow. Carbon dioxide efflux from the meadow was measured from June through September in 2011 and 2012 using soil collars and a LICOR 8100A infrared gas analyzer. Preliminary results show that soil respiration rates are influenced by the hydrologic gradient across the meadow, with drier regions peaking earlier in the summer as compared to wetter regions. We also show that high snowpack years can suppress soil respiration in the meadow until late in the summer season as compared to low snowpack years, where soil respiration peaks early in the summer.

  9. Common variation near CDKN1A, POLD3 and SHROOM2 influences colorectal cancer risk.

    PubMed

    Dunlop, Malcolm G; Dobbins, Sara E; Farrington, Susan Mary; Jones, Angela M; Palles, Claire; Whiffin, Nicola; Tenesa, Albert; Spain, Sarah; Broderick, Peter; Ooi, Li-Yin; Domingo, Enric; Smillie, Claire; Henrion, Marc; Frampton, Matthew; Martin, Lynn; Grimes, Graeme; Gorman, Maggie; Semple, Colin; Ma, Yusanne P; Barclay, Ella; Prendergast, James; Cazier, Jean-Baptiste; Olver, Bianca; Penegar, Steven; Lubbe, Steven; Chander, Ian; Carvajal-Carmona, Luis G; Ballereau, Stephane; Lloyd, Amy; Vijayakrishnan, Jayaram; Zgaga, Lina; Rudan, Igor; Theodoratou, Evropi; Starr, John M; Deary, Ian; Kirac, Iva; Kovacević, Dujo; Aaltonen, Lauri A; Renkonen-Sinisalo, Laura; Mecklin, Jukka-Pekka; Matsuda, Koichi; Nakamura, Yusuke; Okada, Yukinori; Gallinger, Steven; Duggan, David J; Conti, David; Newcomb, Polly; Hopper, John; Jenkins, Mark A; Schumacher, Fredrick; Casey, Graham; Easton, Douglas; Shah, Mitul; Pharoah, Paul; Lindblom, Annika; Liu, Tao; Smith, Christopher G; West, Hannah; Cheadle, Jeremy P; Midgley, Rachel; Kerr, David J; Campbell, Harry; Tomlinson, Ian P; Houlston, Richard S

    2012-05-27

    We performed a meta-analysis of five genome-wide association studies to identify common variants influencing colorectal cancer (CRC) risk comprising 8,682 cases and 9,649 controls. Replication analysis was performed in case-control sets totaling 21,096 cases and 19,555 controls. We identified three new CRC risk loci at 6p21 (rs1321311, near CDKN1A; P = 1.14 × 10(-10)), 11q13.4 (rs3824999, intronic to POLD3; P = 3.65 × 10(-10)) and Xp22.2 (rs5934683, near SHROOM2; P = 7.30 × 10(-10)) This brings the number of independent loci associated with CRC risk to 20 and provides further insight into the genetic architecture of inherited susceptibility to CRC.

  10. Monsoonal influence on variation of hydrochemistry and isotopic signatures: Implications for associated arsenic release in groundwater

    NASA Astrophysics Data System (ADS)

    Majumder, Santanu; Datta, Saugata; Nath, Bibhash; Neidhardt, Harald; Sarkar, Simita; Roman-Ross, Gabriela; Berner, Zsolt; Hidalgo, Manuela; Chatterjee, Debankur; Chatterjee, Debashis

    2016-04-01

    The present study examines the groundwater and surface water geochemistry of two different geomorphic domains within the Chakdaha block, West Bengal, in an attempt to decipher potential influences of groundwater abstraction on the hydrochemical evolution of the aquifer, the effect of different water inputs (monsoon rain, irrigation and downward percolation from surface water impoundments) to the groundwater system and concomitant As release. A low-land flood plain and a natural levee have been selected for this purpose. Although the stable isotopic signatures of oxygen (δ18O) and hydrogen (δ2H) are largely controlled by local precipitation, the isotopic composition falls sub-parallel to the Global Meteoric Water Line (GMWL). The Cl/Br molar ratio indicates vertical recharge into the wells within the flood plain area, especially during the post-monsoon season, while influences of both evaporation and vertical mixing are visible within the natural levee wells. Increase in mean DOC concentrations (from 1.33 to 6.29 mg/L), from pre- to post-monsoon season, indicates possible inflow of organic carbon to the aquifer during the monsoonal recharge. Concomitant increase in AsT, Fe(II) and HCO3- highlights a possible initial episode of reductive dissolution of As-rich Fe-oxyhydroxides. The subsequent sharp increase in the mean As(III) proportions (by 223%), particularly in the flood plain samples during the post-monsoon season, which is accompanied by a slight increase in mean AsT (7%) may refer to anaerobic microbial degradation of DOC coupled with the reduction of As(V) to As(III) without triggering additional As release from the aquifer sediments.

  11. Hamiltonian inclusive fitness: a fitter fitness concept

    PubMed Central

    Costa, James T.

    2013-01-01

    In 1963–1964 W. D. Hamilton introduced the concept of inclusive fitness, the only significant elaboration of Darwinian fitness since the nineteenth century. I discuss the origin of the modern fitness concept, providing context for Hamilton's discovery of inclusive fitness in relation to the puzzle of altruism. While fitness conceptually originates with Darwin, the term itself stems from Spencer and crystallized quantitatively in the early twentieth century. Hamiltonian inclusive fitness, with Price's reformulation, provided the solution to Darwin's ‘special difficulty’—the evolution of caste polymorphism and sterility in social insects. Hamilton further explored the roles of inclusive fitness and reciprocation to tackle Darwin's other difficulty, the evolution of human altruism. The heuristically powerful inclusive fitness concept ramified over the past 50 years: the number and diversity of ‘offspring ideas’ that it has engendered render it a fitter fitness concept, one that Darwin would have appreciated. PMID:24132089

  12. Oxygen isotope variation in primitive achondrites: The influence of primordial, asteroidal and terrestrial processes

    NASA Astrophysics Data System (ADS)

    Greenwood, R. C.; Franchi, I. A.; Gibson, J. M.; Benedix, G. K.

    2012-10-01

    A detailed oxygen isotope study of the acapulcoites, lodranites, winonaites, brachinites and various related achondrites has been undertaken to investigate the nature of their precursor materials. High levels of terrestrial alteration displayed by many of these samples have been mitigated by leaching in ethanolamine thioglycollate (EATG) solution. Due to their high metal and sulphide content, acapulcoite, lodranite and winonaite samples show much greater isotopic shifts during weathering than brachinites. As observed in previous studies, Antarctic weathered finds are displaced to lighter oxygen isotope compositions and non-Antarctic finds to heavier values. Leached primitive achondrite residues continue to show high levels of oxygen isotope heterogeneity. This variation is reflected in the 2σ error on group mean Δ17O values, which decrease in the following order: acapulcoite-lodranite clan > brachinites > winonaites. On an oxygen three-isotope diagram, the acapulcoite--lodranite clan define a limited trend with a slope of 0.61 ± 0.08 and an intercept of -1.43 ± 0.27 (R2 = 0.78). A broad positive correlation between Δ17O and olivine fayalite contents displayed by both acapulcoite and lodranite samples may be the result of early aqueous alteration and subsequent dehydration. Winonaites experienced a greater degree of differentiation than the acapulcoite-lodranite clan and define a distinct mass fractionation line, with a slope of 0.53 ± 0.01 and an intercept of -0.53 ± 0.04 (R2 = 1). A number of samples currently classified as acapulcoites (NWA 725, NWA 1052 and Dho 1222) have oxygen isotope compositions indicating that they are winonaites. The relatively high level of oxygen isotope heterogeneity displayed by the brachinites supports their designation as primitive achondrites. A number of ungrouped olivine-rich achondrites (Divnoe, NWA 4042, NWA 4363, NWA 4518, NWA 5400, Zag (b)) as well as the unique plagioclase-rich achondrites GRA 06128 and GRA 06129 have

  13. Variation in multiple traits of vegetative and reproductive seagrass tissues influences plant-herbivore interactions.

    PubMed

    Vergés, Adriana; Becerro, Mikel A; Alcoverro, Teresa; Romero, Javier

    2007-04-01

    Plant-herbivore interactions have strong ecological and evolutionary consequences, but have been traditionally overlooked in marine higher plants. Despite recent advances in seagrass ecology that highlight the importance of herbivory, the mechanisms that regulate the feeding behaviour of seagrass consumers remain largely unknown. Herbivores have been shown to reduce the sexual reproductive success of seagrasses through direct consumption of inflorescences and seeds, but we know little about intraspecific variation in susceptibility to grazing of different seagrass tissues. We contrasted the relative palatability of reproductive and vegetative tissues of the temperate seagrass Posidonia oceanica in the field, and we assessed the feeding preferences among these tissues of the main consumers of the plant, the fish Sarpa salpa and the urchin Paracentrotus lividus. Moreover, we identified the plant traits that explained the observed feeding behaviour. We provide strong evidence for herbivore selectivity among seagrass tissues. In the field, 70-90% of inflorescences were damaged by herbivores compared to 3-60% of leaves of similar age. In feeding assays, the urchin P. lividus showed over a twofold preference for reproductive tissue at various stages of development. By contrast, we detected no feeding activity on either leaves or inflorescences from the fish S. salpa, which is known to migrate to deeper waters soon after flowering starts and during the period of fruit maturation. Despite being the preferred food of urchins, inflorescences were chemically defended, had higher levels of phenolics and lower nutrient and calorific content than leaves. We experimentally demonstrated that leaf structural defences are the primary factor in determining urchin feeding preferences. Removal of plant structure results in a drastic shift in urchin selectivity towards the most nutritious and less chemically defended leaf tissue, indicating that multiple mechanisms of defence to

  14. Temporal variation of diatom benthic propagules in a monsoon-influenced tropical estuary

    NASA Astrophysics Data System (ADS)

    Patil, Jagadish S.; Anil, Arga Chandrashekar

    2008-10-01

    Temporal variations in the diatom benthic propagule (DBP) community and their role in the phytoplankton community in a monsoon-affected tropical estuary, Zuari estuary, Goa (India) are presented. The DBP from the sediments was enumerated using an extinction dilution method (most probable number method), which allows estimation of resting stages through examination of germinated vegetative cells in culture. The DBP community was dominated by planktonic species belonging to the genera Skeletonema, Fragilariopsis, Thalassiosira, and Chaetoceros. Benthic propagules (BPs) of Skeletonema costatum and Fragilariopsis sp. were dominant throughout the year. Between these two species, only S. costatum showed a linear relationship between the BP and planktonic cells, indicating that this species is particularly important in coupling of pelagic and benthic ecosystems. During the onset and restart of monsoon after an intermittent break, water column was stratified, with a low-salinity layer arising from riverine discharge and precipitation at the surface and relatively cold, saline, low-oxygen waters at the bottom. Stratification favored blooming of S. costatum and Fragilariopsis sp. in nutrient-rich surface and bottom waters, respectively. The decline in these blooms ensuing nitrate depletion and salinity change resulted in an increased abundance of BP. Chaetoceros bloom was observed during the monsoon break as well as during non-monsoon period and on both the occasions the decline in bloom was coupled with freshwater discharge. During the non-monsoon season, Thalassiosira blooms were encountered subsequent to high nitrate inputs. These findings suggest that in such shallow tropical regions, physical processes during monsoon (freshwater discharge) and non-monsoon seasons (currents, waves and tides) cause resuspension of diatom BP. Since light is not a limiting factor for germination in such regions, the blooming of resuspended BP depends on nutrient availability.

  15. How do starspots influence the transit timing variations of exoplanets? Simulations of individual and consecutive transits

    NASA Astrophysics Data System (ADS)

    Ioannidis, P.; Huber, K. F.; Schmitt, J. H. M. M.

    2016-01-01

    Transit timing variations (TTVs) of exoplanets are normally interpreted as the consequence of gravitational interaction with additional bodies in the system. However, TTVs can also be caused by deformations of the system transits by starspots, which might thus pose a serious complication in their interpretation. We therefore simulate transit light curves deformed by spot-crossing events for different properties of the stellar surface and the planet, such as starspot position, limb darkening, planetary period, and impact parameter. Mid-transit times determined from these simulations can be significantly shifted with respect to the input values; these shifts cannot be larger than 1% of the transit duration and depend very strongly on the longitudinal position of the spot during the transit and the transit duration. Consequently, TTVs with amplitudes larger than the above limit are very unlikely to be caused by starspots. We also investigate whether TTVs from sequences of consecutive transits with spot-crossing anomalies can be misinterpreted as the result of an additional body in the system. We use the Generalized Lomb-Scargle periodogram to search for periods in TTVs and conclude that low-amplitude TTVs with statistically significant periods around active stars are the most problematic cases. In those cases where the photometric precision is high enough to inspect the transit shapes for deformations it should be possible to identify TTVs caused by starspots; however, especially for cases with low signal-to-noise in transit (TSNR ≲ 15) light curves it becomes quite difficult to reliably decide whether these periods come from starspots, physical companions in the system, or if they are random noise artifacts.

  16. Factors influencing variation of bulk milk antibiotic residue occurrence, somatic cell count, and total bacterial count in dairy sheep flocks.

    PubMed

    Gonzalo, C; Carriedo, J A; García-Jimeno, M C; Pérez-Bilbao, M; de la Fuente, L F

    2010-04-01

    To study the variations of bulk tank milk variables in dairy ewe flocks and to identify the main target practices and flock groups to improve milk quality and safety, a total of 71,228 records of antibiotic residue (AR) and milk yield and 68,781 records of somatic cell count (SCC) and total bacterial count (TBC) were obtained over 5 yr from the same 209 dairy ewe flocks of the Assaf breed belonging to the Consortium for Ovine Promotion of Castilla-León (Spain). Based on a logistic regression model, year, month, semester, SCC, TBC, dry therapy, and milk yield significantly contributed to AR variation. High SCC was associated with increased AR violations. When antibiotic dry therapy was implemented, AR occurrence was higher than when this practice was not used. A polynomial monthly distribution throughout the year was observed for AR occurrence; the highest values were in autumn, coinciding with low milk yields per flock. Yearly occurrences drastically diminished from 2004 (1.36%) to 2008 (0.30%), probably as a result of effective educational programs. The mixed-model ANOVA of factors influencing variation in SCC and TBC indicated that year, month, AR, dry therapy group, milking type, and year interactions were significant variation factors for SCC and TBC; mathematical model accounted for 74.1 and 35.4% of total variance for each variable, respectively. Differences in management and hygiene practice caused significant SCC and TBC variations among flocks and within flocks throughout the 5-yr study. Over time, continuously dry treated flocks showed lower logSCC (5.80) and logTBC (4.92) than untreated (6.10 and 5.18, respectively) or discontinuously dry treated (6.01 and 5.05, respectively) flocks. Continuously dry treated flocks had lower AR occurrences than did discontinuously dry treated flocks. As a whole, AR occurrence and SCC and TBC bulk tank milk variables can be used for monitoring mammary health and milk hygiene and safety in dairy sheep throughout time.

  17. Influence of the mechanical coupling and inherited strength variations on the geometry of continental rifts.

    NASA Astrophysics Data System (ADS)

    Philippon, Melody; van Delft, Pim; van Winden, Matthijs; Zamuroviç, Dejan; Sokoutis, Dimitrios; Willingshofer, Ernst; Cloetingh, Sierd

    2013-04-01

    The geometry of continental rifts is strongly controlled by the rheology of the lithosphere at the onset of rifting. This initial geometry will further control the development of ocean spreading centers and the structure of adjacent passive margins. Therefore, understanding the influence of coupling between the different layers of the lithosphere with and without laterally variable strength in the crust is key when investigating continental rifts. In this study we infer the influence of coupling in the crust on the rift geometry by means of crustal scale analogue experiments, where we characterize the response of the crust to deformation in terms of the strength ratio between brittle and ductile crust. The degree of coupling has been varied for setups containing or not a pre-existing weak zone. To allow a better description of the geometry obtained in our models, some key observations such as: a) the degree of tilting of the blocks, b) the total width of the graben, c) the displacement along the main fault and d) the distribution of thinning in the lower crust are monitored. Models containing a weak zone are compared to natural examples of the inherited Mozambique Ocean suture zones (MOSZ) in the Red Sea rift. The modelling results suggest that deformation is not a-priori localized within pre-existing weak zones unless the coupling between the brittle and the ductile crust is high. With respect to the MOSZ, we infer that: (1) Jurassic NW-SE trending grabens developed parallel to but not within the MOSZ and hence reflect a low degree of coupling whereas (2) Eocene rifting in the Red Sea occurred under coupled conditions as deformation strongly focused within the MOSZ. Models without weak zone shows that large-scale detachment faults can also form within a highly coupled crust, which is at variance to the common perception that detachment faulting demands strong decoupling. Our findings shed light on natural rift systems, which show a wide range of geometries that

  18. Variation in the location of the shoe sole flexion point influences plantar loading patterns during gait

    PubMed Central

    2014-01-01

    Background Several footwear design characteristics are known to have detrimental effects on the foot. However, one characteristic that has received relatively little attention is the point where the sole flexes in the sagittal plane. Several footwear assessment forms assume that this should ideally be located directly under the metarsophalangeal joints (MTPJs), but this has not been directly evaluated. The aim of this study was therefore to assess the influence on plantar loading of different locations of the shoe sole flexion point. Method Twenty-one asymptomatic females with normal foot posture participated. Standardised shoes were incised directly underneath the metatarsophalangeal joints, proximal to the MTPJs or underneath the midfoot. The participants walked in a randomised sequence of the three shoes whilst plantar loading patterns were obtained using the Pedar® in-shoe pressure measurement system. The foot was divided into nine anatomically important masks, and peak pressure (PP), contact time (CT) and pressure time integral (PTI) were determined. A ratio of PP and PTI between MTPJ2-3/MTPJ1 was also calculated. Results Wearing the shoe with the sole flexion point located proximal to the MTPJs resulted in increased PP under MTPJ 4–5 (6.2%) and decreased PP under the medial midfoot compared to the sub-MTPJ flexion point (−8.4%). Wearing the shoe with the sole flexion point located under the midfoot resulted in decreased PP, CT and PTI in the medial and lateral hindfoot (PP: −4.2% and −5.1%, CT: −3.4% and −6.6%, PTI: −6.9% and −5.7%) and medial midfoot (PP: −5.9% CT: −2.9% PTI: −12.2%) compared to the other two shoes. Conclusion The findings of this study indicate that the location of the sole flexion point of the shoe influences plantar loading patterns during gait. Specifically, shoes with a sole flexion point located under the midfoot significantly decrease the magnitude and duration of loading under the midfoot and hindfoot, which

  19. Jet mixing into a heated cross flow in a cylindrical duct: Influence of geometry and flow variations

    NASA Technical Reports Server (NTRS)

    Hatch, M. S.; Sowa, W. A.; Samuelsen, G. S.; Holdeman, J. D.

    1992-01-01

    To examine the mixing characteristics of jets in an axi-symmetric can geometry, temperature measurements were obtained downstream of a row of cold jets injected into a heated cross stream. Parametric, non-reacting experiments were conducted to determine the influence of geometry and flow variations on mixing patterns in a cylindrical configuration. Results show that jet to mainstream momentum flux ratio and orifice geometry significantly impact the mixing characteristics of jets in a can geometry. For a fixed number of orifices, the coupling between momentum flux ratio and injector determines (1) the degree of jet penetration at the injection plane, and (2) the extent of circumferential mixing downstream of the injection plane. The results also show that, at a fixed momentum flux ratio, jet penetration decreases with (1) an increase in slanted slot aspect ratio, and (2) an increase in the angle of the slots with respect to the mainstream direction.

  20. Methylation interactions in Arabidopsis hybrids require RNA-directed DNA methylation and are influenced by genetic variation.

    PubMed

    Zhang, Qingzhu; Wang, Dong; Lang, Zhaobo; He, Li; Yang, Lan; Zeng, Liang; Li, Yanqiang; Zhao, Cheng; Huang, Huan; Zhang, Heng; Zhang, Huiming; Zhu, Jian-Kang

    2016-07-19

    DNA methylation is a conserved epigenetic mark in plants and many animals. How parental alleles interact in progeny to influence the epigenome is poorly understood. We analyzed the DNA methylomes of Arabidopsis Col and C24 ecotypes, and their hybrid progeny. Hybrids displayed nonadditive DNA methylation levels, termed methylation interactions, throughout the genome. Approximately 2,500 methylation interactions occurred at regions where parental DNA methylation levels are similar, whereas almost 1,000 were at differentially methylated regions in parents. Methylation interactions were characterized by an abundance of 24-nt small interfering RNAs. Furthermore, dysfunction of the RNA-directed DNA methylation pathway abolished methylation interactions but did not affect the increased biomass observed in hybrid progeny. Methylation interactions correlated with altered genetic variation within the genome, suggesting that they may play a role in genome evolution. PMID:27382183

  1. Influence of Temperature Variation on Field Effect Transistor Properties Using a Solution-Processed Liquid Crystalline Semiconductor, 8TNAT8.

    PubMed

    Monobe, Hirosato; Kimoto, Masaomi; Shimizu, Yo

    2016-04-01

    In this study, we used a liquid crystalline (LC) semiconductor, 8TNAT8, solution (e.g., 0.1 wt% in toluene) for forming an organic semiconductor layer by solution casting method, and fabricated bottom-gate/bottom-contact type field effect transistors (FETs). These LC semiconductors show FET characteristic properties and have high carrier mobility of 0.01 cm2 V-1 s-1. We have investigated the surface morphology and the influence of temperature variation on LC FET properties across the phase transition from crystal to mesophase of a LC semiconductor, 8TNAT8. In the most cases, FET mobility was irreversibly decreased after. temperature heat stress above the melting point of 8TNAT8, owing to the morphological change of LC layer. PMID:27451617

  2. Defect Generation and Propagation in MC-Si Ingots: Influence on Cell-to-Cell Performance Variation

    SciTech Connect

    Sopori, B.; Rupnowski, P.; Shet, S.; Mehta, V.; Seacrist, M.; Shi, G.; Chen, J.; Deshpande, A.

    2011-01-01

    This paper describes results of our study aimed at understanding mechanism(s) of dislocation generation and propagation in multicrystalline silicon (mc-Si) ingots, and evaluating their influence on the solar cell performance. This work was done in two parts: (i) Measurement of dislocation distributions along various bricks, selected from strategic locations within several ingots; and (ii) Theoretical modeling of the cell performance corresponding to the measured dislocation distributions. Solar cells were fabricated on wafers of known dislocation distribution, and the results were compared with the theory. These results show that cell performance can be accurately predicted from the dislocation distribution, and the changes in the dislocation distribution are the primary cause for variations in the cell-to-cell performance. The dislocation generation and propagation mechanisms, suggested by our results, are described in this paper.

  3. Influence of influent wastewater communities on temporal variation of activated sludge communities.

    PubMed

    Lee, Sang-Hoon; Kang, Hyun-Jin; Park, Hee-Deung

    2015-04-15

    Continuously feeding influent wastewater containing diverse bacterial species to a wastewater treatment activated sludge bioreactor may influence the activated sludge bacterial community temporal dynamics. To explore this possibility, this study tracked influent wastewater and activated sludge bacterial communities by pyrosequencing 16S rRNA genes from four full-scale wastewater treatment plants over a 9-month period. The activated sludge communities showed significantly higher richness and evenness than the influent wastewater communities. Furthermore, the two communities were different in composition and temporal dynamics. These results demonstrate that the impact of the influent wastewater communities on the activated sludge communities was weak. Nevertheless, 4.3-9.3% of the operational taxonomic units (OTUs) detected in the activated sludge were shared with the influent wastewater, implying contribution from influent wastewater communities to some extent. However, the relative OTU abundance of the influent wastewater was not maintained in the activated sludge communities (i.e., weak neutral assembly). In addition, the variability of the communities of the shared OTUs was moderately correlated with abiotic factors imposed to the bioreactors. Taken together, temporal dynamics of activated sludge communities appear to be predominantly explained by species sorting processes in response to influent wastewater communities. PMID:25655320

  4. Political disagreement in intergroup terms: contextual variation and the influence of power.

    PubMed

    OBrien, Léan V; McGarty, Craig

    2009-03-01

    In two studies we examined justified attributions made in the face of political disagreement. Study 1 showed that Australian supporters and opponents of Australian involvement in the 2003 invasion of Iraq made stereotypical attributions that justified the superiority of the in-group over the out-group. Stereotypical attributions were consistent with the justification that the supporters of the war had been misled by dishonest political leaders. Study 2 replicated this pattern with supporters and opponents of Australia's policy of mandatory detention of asylum seekers. It also identified pragmatism as a dimension that dominant, government-aligned, groups may use to justify the superiority of the in-group over the out-group. In both studies political leaders were seen as more competent than members of the public. The results show the influence of intergroup power and within-group leader/supporter distinctions on people's attributions about political disagreement. They point to the power of social psychological theory to help analyse important contemporary political concerns.

  5. Geographic variations in anthropogenic drivers that influence the vulnerability and resilience of social-ecological systems.

    PubMed

    Forbes, Bruce C; Fresco, Nancy; Shvidenko, Anatoly; Danell, Kjell; Chapin, F Stuart

    2004-08-01

    Across the circumpolar North large disparities in the distribution of renewable and nonrenewable resources, human population density, capital investments, and basic residential and transportation infrastructure combine to create recognizable hotspots of recent and foreseeable change. Northern Fennoscandia exemplifies a relatively benign situation due to its current economic and political stability. Northern Russia is experiencing rapid, mostly negative changes reflecting the general state of crisis since the collapse of the Soviet Union. North America enjoys a relatively stable regulatory structure to mitigate environmental degradation associated with industry, but is on the verge of approving massive new development schemes that would significantly expand the spatial extent of potentially affected social-ecological systems. Institutional or regulatory context influences the extent to which ecosystem services are buffered against environmental change. With or without a warming climate, certain geographic areas appear especially vulnerable to damages that may threaten their ability to supply goods and services in the near future. Climate change may exacerbate this situation in some places but may offer opportunities to enhance resilience in the long term.

  6. Influence of gene interaction on complex trait variation with multilocus models.

    PubMed

    Mäki-Tanila, Asko; Hill, William G

    2014-09-01

    Although research effort is being expended into determining the importance of epistasis and epistatic variance for complex traits, there is considerable controversy about their importance. Here we undertake an analysis for quantitative traits utilizing a range of multilocus quantitative genetic models and gene frequency distributions, focusing on the potential magnitude of the epistatic variance. All the epistatic terms involving a particular locus appear in its average effect, with the number of two-locus interaction terms increasing in proportion to the square of the number of loci and that of third order as the cube and so on. Hence multilocus epistasis makes substantial contributions to the additive variance and does not, per se, lead to large increases in the nonadditive part of the genotypic variance. Even though this proportion can be high where epistasis is antagonistic to direct effects, it reduces with multiple loci. As the magnitude of the epistatic variance depends critically on the heterozygosity, for models where frequencies are widely dispersed, such as for selectively neutral mutations, contributions of epistatic variance are always small. Epistasis may be important in understanding the genetic architecture, for example, of function or human disease, but that does not imply that loci exhibiting it will contribute much genetic variance. Overall we conclude that theoretical predictions and experimental observations of low amounts of epistatic variance in outbred populations are concordant. It is not a likely source of missing heritability, for example, or major influence on predictions of rates of evolution.

  7. Geographic variations in anthropogenic drivers that influence the vulnerability and resilience of social-ecological systems.

    PubMed

    Forbes, Bruce C; Fresco, Nancy; Shvidenko, Anatoly; Danell, Kjell; Chapin, F Stuart

    2004-08-01

    Across the circumpolar North large disparities in the distribution of renewable and nonrenewable resources, human population density, capital investments, and basic residential and transportation infrastructure combine to create recognizable hotspots of recent and foreseeable change. Northern Fennoscandia exemplifies a relatively benign situation due to its current economic and political stability. Northern Russia is experiencing rapid, mostly negative changes reflecting the general state of crisis since the collapse of the Soviet Union. North America enjoys a relatively stable regulatory structure to mitigate environmental degradation associated with industry, but is on the verge of approving massive new development schemes that would significantly expand the spatial extent of potentially affected social-ecological systems. Institutional or regulatory context influences the extent to which ecosystem services are buffered against environmental change. With or without a warming climate, certain geographic areas appear especially vulnerable to damages that may threaten their ability to supply goods and services in the near future. Climate change may exacerbate this situation in some places but may offer opportunities to enhance resilience in the long term. PMID:15387078

  8. Genetic, environmental and epigenetic influences on variation in human tooth number, size and shape.

    PubMed

    Townsend, Grant; Bockmann, Michelle; Hughes, Toby; Brook, Alan

    2012-01-01

    The aim of this review is to highlight some key recent developments in studies of tooth number, size and shape that are providing better insights into the roles of genetic, environmental and epigenetic factors in the process of dental development. Advances in molecular genetics are helping to clarify how epigenetic factors influence the spatial and temporal regulation of the complex processes involved in odontogenesis. At the phenotypic level, the development of sophisticated systems for image analysis is enabling new dental phenotypes to be defined. The 2D and 3D data that are generated by these imaging systems can then be analysed with mathematical approaches, such as geometric morphometric analysis. By gathering phenotypic data and DNA from twins, it is now possible to use 'genome-wide' association studies and the monozygotic co-twin design to identify important genes in odontogenesis and also to clarify how epigenetic and environmental factors can affect this process. Given that many of the common dental anomalies affecting the human dentition are interrelated, apparently reflecting pleiotropic genetic effects, the discoveries and new directions described in this paper should have important implications for clinical dental practice in the future.

  9. Influence of Curve Number variation on peak discharge of small catchment

    NASA Astrophysics Data System (ADS)

    Banasik, Kazimierz; Hejduk, Leszek; Banasik, Jerzy; Rutkowska, Agnieszka

    2014-05-01

    In this study, we have examined the impact of Curve Number variability on peak discharge, estimated with the use of lumped parametric model SEGMO. Analysis has been conducted for a small (82 km2) agro-forested lowland catchment, located in the center of Poland. Both, the curve number, which is determining runoff depth from rainfall depth, and the IUH characteristics (such as lag time, time to peak, maximum ordinate), which are used to transform the runoff depth into direct runoff hydrograph, have been estimated on the base of recorded in the catchment rainfall-runoff events (Banasik et al. 2011, Banasik et al. 2013). All of them include some stochastic variables, however IUH has been approximated, and used in computation as deterministic. A big variability in CNs has been found, when they were computed from recorded rainfall-runoff data. Next, using the 40 rainfall-runoff data set, the curve numbers were computed again, for each of the ordered pairs, and finally plotted against rainfall depth. Curve numbers were found to approximate an exponential function, varying with storm depth (i.e. decreasing with rainfall increase), and approaches a constant value (CN∞=69.8, which was very close to that value estimated on the base of soil type and land use) at higher rainfalls, what is call a standard behavior (Van Mullem et al. 2002). Standard error of estimation of CN was 1.54. The examination indicated high sensitivity of the flood discharge, estimated as catchment response to 100-year rainfall, to CN changes. Banasik K., Hejduk L. & Oygarden L., 2011. Prediction and reduction of diffuse pollution, solid emission and extreme flows from rural areas - case study of small agricultural catchments. Warsaw University of Life Sciences Press, Warsaw. Banasik K., Hejduk L., Banasik J., 2013. Variation of IUH shapes with size of rainfall-runoff events in a small agricultural catchment. EGU General Assembly, Abstract & Poster. Van Mullem J.A., Woodward D.E., Hawkins R

  10. Patient, Physician and Organizational Influences on Variation in Antipsychotic Prescribing Behavior

    PubMed Central

    Tang, Yan; Chang, Chung-Chou H.; Lave, Judith R.; Gellad, Walid F.; Huskamp, Haiden A.; Donohue, Julie M.

    2016-01-01

    Background Physicians face the choice of multiple ingredients when prescribing drugs in many therapeutic categories. For conditions with considerable patient heterogeneity in treatment response, customizing treatment to individual patient needs and preferences may improve outcomes. Aims of the Study To assess variation in the diversity of antipsychotic prescribing for mental health conditions, a necessary although not sufficient condition for personalizing treatment. To identify patient caseload, physician, and organizational factors associated with the diversity of antipsychotic prescribing. Methods Using 2011 data from Pennsylvania’s Medicaid program, IMS Health’s HCOS™ database, and the AMA Masterfile, we identified 764 psychiatrists who prescribed antipsychotics to ≥10 patients. We constructed three physician-level measures of diversity/concentration of antipsychotic prescribing: number of ingredients prescribed, share of prescriptions for most preferred ingredient, and Herfindahl-Hirschman index (HHI). We used multiple membership linear mixed models to examine patient caseload, physician, and healthcare organizational predictors of physician concentration of antipsychotic prescribing. Results There was substantial variability in antipsychotic prescribing concentration among psychiatrists, with number of ingredients ranging from 2-17, share for most preferred ingredient from 16%-85%, and HHI from 1,088-7,270. On average, psychiatrist prescribing behavior was relatively diversified; however, 11% of psychiatrists wrote an average of 55% of their prescriptions for their most preferred ingredient. Female prescribers and those with smaller shares of disabled or serious mental illness patients had more concentrated prescribing behavior on average. Discussion Antipsychotic prescribing by individual psychiatrists in a large state Medicaid program varied substantially across psychiatrists. Our findings illustrate the importance of understanding physicians

  11. The influence of partial panmixia on neutral models of spatial variation.

    PubMed

    Nagylaki, Thomas

    2011-01-01

    Partial panmixia can be regarded as the limiting case of long-distance migration. The effect of incorporating partial panmixia into neutral models of geographical variation is investigated. The monoecious, diploid population is subdivided into randomly mating colonies that exchange gametes independently of genotype. The gametes fuse wholly at random, including self-fertilization. Generations are discrete and nonoverlapping; the analysis is restricted to a single locus; every allele mutates to new alleles at the same rate. Introducing some panmixia intensifies sufficiently weak migration. A general formula is derived for the migration effective population number, N(e), and N(e) is evaluated explicitly in a number of models with nonconservative migration. Usually, N(e) increases as the panmictic rate, b, increases; in particular, this result holds for two demes, and generically if the underlying migration is either sufficiently weak or panmixia is sufficiently strong. However, in an analytic model, there exists an open set of parameters for which N(e) decreases as b increases. Migration is conservative in the island and circular-habitat models, which are studied in detail. In the former, including some panmixia simply alters the underlying migration rate, increasing (decreasing) it if it is less (greater) than the panmictic value. For the circular habitat, the probability of identity in allelic state at equilibrium is calculated in a nonlocal, continuous-space, continuous-time approximation. In both models, by an efficient, general method, the expected homozygosity, effective number of alleles, and differentiation of gene frequencies are evaluated and discussed; their monotonicity properties with respect to all the parameters are determined; and in the model of infinitely many sites, the mean coalescence times and nucleotide diversities are studied similarly. For the probability of identity at equilibrium in the unbounded stepping-stone model in arbitrarily many

  12. Corticotropin-Releasing Hormone Receptor Type 1 (CRHR1) Genetic Variation and Stress Interact to Influence Reward Learning

    PubMed Central

    Bogdan, Ryan; Santesso, Diane L.; Fagerness, Jesen; Perlis, Roy H.; Pizzagalli, Diego A.

    2011-01-01

    Stress is a general risk factor for psychopathology but the mechanisms underlying this relationship remain largely unknown. Animal studies and limited human research suggest that stress can induce anhedonic behavior. Moreover, emerging data indicate that genetic variation within the corticotropin-releasing hormone type 1 receptor gene (CRHR1) at rs12938031 may promote psychopathology, particularly in the context of stress. Using an intermediate phenotypic neurogenetics approach, we assessed how stress and CRHR1 genetic variation (rs12938031) influence reward learning, an important component of anhedonia. Psychiatrically healthy female participants (n = 75) completed a probabilistic reward learning task during stress and no-stress conditions while 128-channel event-related potentials were recorded. Fifty-six participants were also genotyped across CRHR1. Response bias, an individual’s ability to modulate behavior as a function of reward, was the primary behavioral variable of interest. The feedback-related positivity (FRP) in response to reward feedback was used as a neural index of reward learning. Relative to the no-stress condition, acute stress was associated with blunted response bias as well as a smaller and delayed FRP (indicative of disrupted reward learning) and reduced anterior cingulate and orbitofrontal cortex activation to reward. Critically, rs12938031 interacted with stress to influence reward learning: both behaviorally and neurally, A homozygotes showed stress-induced reward learning abnormalities. These findings indicate that acute, uncontrollable stressors reduce participants’ ability to modulate behavior as a function of reward, and that such effects are modulated by CRHR1 genotype. Homozygosity for the A allele at rs12938031 may increase risk for psychopathology via stress-induced reward learning deficits. PMID:21917807

  13. Temporal Variations of Water Productivity in Irrigated Corn: An Analysis of Factors Influencing Yield and Water Use across Central Nebraska

    PubMed Central

    Carr, Tony; Yang, Haishun; Ray, Chittaranjan

    2016-01-01

    Water Productivity (WP) of a crop defines the relationship between the economic or physical yield of the crop and its water use. With this concept it is possible to identify disproportionate water use or water-limited yield gaps and thereby support improvements in agricultural water management. However, too often important qualitative and quantitative environmental factors are not part of a WP analysis and therefore neglect the aspect of maintaining a sustainable agricultural system. In this study, we examine both the physical and economic WP in perspective with temporally changing environmental conditions. The physical WP analysis was performed by comparing simulated maximum attainable corn yields per unit of water using the crop model Hybrid-Maize with observed data from 2005 through 2013 from 108 farm plots in the Central Platte and the Tri Basin Natural Resource Districts of Nebraska. In order to expand the WP analysis on external factors influencing yields, a second model, Maize-N, was used to estimate optimal nitrogen (N)–fertilizer rate for specific fields in the study area. Finally, a vadose zone flow and transport model, HYDRUS-1D for simulating vertical nutrient transport in the soil, was used to estimate locations of nitrogen pulses in the soil profile. The comparison of simulated and observed data revealed that WP was not on an optimal level, mainly due to large amounts of irrigation used in the study area. The further analysis illustrated year-to-year variations of WP during the nine consecutive years, as well as the need to improve fertilizer management to favor WP and environmental quality. In addition, we addressed the negative influence of groundwater depletion on the economic WP through increasing pumping costs. In summary, this study demonstrated that involving temporal variations of WP as well as associated environmental and economic issues can represent a bigger picture of WP that can help to create incentives to sustainably improve

  14. Corticotropin-releasing hormone receptor type 1 (CRHR1) genetic variation and stress interact to influence reward learning.

    PubMed

    Bogdan, Ryan; Santesso, Diane L; Fagerness, Jesen; Perlis, Roy H; Pizzagalli, Diego A

    2011-09-14

    Stress is a general risk factor for psychopathology, but the mechanisms underlying this relationship remain largely unknown. Animal studies and limited human research suggest that stress can induce anhedonic behavior. Moreover, emerging data indicate that genetic variation within the corticotropin-releasing hormone type 1 receptor gene (CRHR1) at rs12938031 may promote psychopathology, particularly in the context of stress. Using an intermediate phenotypic neurogenetics approach, we assessed how stress and CRHR1 genetic variation (rs12938031) influence reward learning, an important component of anhedonia. Psychiatrically healthy female participants (n = 75) completed a probabilistic reward learning task during stress and no-stress conditions while 128-channel event-related potentials were recorded. Fifty-six participants were also genotyped across CRHR1. Response bias, an individual's ability to modulate behavior as a function of reward, was the primary behavioral variable of interest. The feedback-related positivity (FRP) in response to reward feedback was used as a neural index of reward learning. Relative to the no-stress condition, acute stress was associated with blunted response bias as well as a smaller and delayed FRP (indicative of disrupted reward learning) and reduced anterior cingulate and orbitofrontal cortex activation to reward. Critically, rs12938031 interacted with stress to influence reward learning: both behaviorally and neurally, A homozygotes showed stress-induced reward learning abnormalities. These findings indicate that acute, uncontrollable stressors reduce participants' ability to modulate behavior as a function of reward, and that such effects are modulated by CRHR1 genotype. Homozygosity for the A allele at rs12938031 may increase risk for psychopathology via stress-induced reward learning deficits.

  15. Temporal Variations of Water Productivity in Irrigated Corn: An Analysis of Factors Influencing Yield and Water Use across Central Nebraska.

    PubMed

    Carr, Tony; Yang, Haishun; Ray, Chittaranjan

    2016-01-01

    Water Productivity (WP) of a crop defines the relationship between the economic or physical yield of the crop and its water use. With this concept it is possible to identify disproportionate water use or water-limited yield gaps and thereby support improvements in agricultural water management. However, too often important qualitative and quantitative environmental factors are not part of a WP analysis and therefore neglect the aspect of maintaining a sustainable agricultural system. In this study, we examine both the physical and economic WP in perspective with temporally changing environmental conditions. The physical WP analysis was performed by comparing simulated maximum attainable corn yields per unit of water using the crop model Hybrid-Maize with observed data from 2005 through 2013 from 108 farm plots in the Central Platte and the Tri Basin Natural Resource Districts of Nebraska. In order to expand the WP analysis on external factors influencing yields, a second model, Maize-N, was used to estimate optimal nitrogen (N)-fertilizer rate for specific fields in the study area. Finally, a vadose zone flow and transport model, HYDRUS-1D for simulating vertical nutrient transport in the soil, was used to estimate locations of nitrogen pulses in the soil profile. The comparison of simulated and observed data revealed that WP was not on an optimal level, mainly due to large amounts of irrigation used in the study area. The further analysis illustrated year-to-year variations of WP during the nine consecutive years, as well as the need to improve fertilizer management to favor WP and environmental quality. In addition, we addressed the negative influence of groundwater depletion on the economic WP through increasing pumping costs. In summary, this study demonstrated that involving temporal variations of WP as well as associated environmental and economic issues can represent a bigger picture of WP that can help to create incentives to sustainably improve

  16. Temporal Variations of Water Productivity in Irrigated Corn: An Analysis of Factors Influencing Yield and Water Use across Central Nebraska.

    PubMed

    Carr, Tony; Yang, Haishun; Ray, Chittaranjan

    2016-01-01

    Water Productivity (WP) of a crop defines the relationship between the economic or physical yield of the crop and its water use. With this concept it is possible to identify disproportionate water use or water-limited yield gaps and thereby support improvements in agricultural water management. However, too often important qualitative and quantitative environmental factors are not part of a WP analysis and therefore neglect the aspect of maintaining a sustainable agricultural system. In this study, we examine both the physical and economic WP in perspective with temporally changing environmental conditions. The physical WP analysis was performed by comparing simulated maximum attainable corn yields per unit of water using the crop model Hybrid-Maize with observed data from 2005 through 2013 from 108 farm plots in the Central Platte and the Tri Basin Natural Resource Districts of Nebraska. In order to expand the WP analysis on external factors influencing yields, a second model, Maize-N, was used to estimate optimal nitrogen (N)-fertilizer rate for specific fields in the study area. Finally, a vadose zone flow and transport model, HYDRUS-1D for simulating vertical nutrient transport in the soil, was used to estimate locations of nitrogen pulses in the soil profile. The comparison of simulated and observed data revealed that WP was not on an optimal level, mainly due to large amounts of irrigation used in the study area. The further analysis illustrated year-to-year variations of WP during the nine consecutive years, as well as the need to improve fertilizer management to favor WP and environmental quality. In addition, we addressed the negative influence of groundwater depletion on the economic WP through increasing pumping costs. In summary, this study demonstrated that involving temporal variations of WP as well as associated environmental and economic issues can represent a bigger picture of WP that can help to create incentives to sustainably improve

  17. Influence of late Quaternary climate change on present patterns of genetic variation in valley oak, Quercus lobata Née.

    PubMed

    Gugger, Paul F; Ikegami, Makihiko; Sork, Victoria L

    2013-07-01

    Phylogeography and ecological niche models (ENMs) suggest that late Quaternary glacial cycles have played a prominent role in shaping present population genetic structure and diversity, but have not applied quantitative methods to dissect the relative contribution of past and present climate vs. other forces. We integrate multilocus phylogeography, climate-based ENMs and multivariate statistical approaches to infer the effects of late Quaternary climate change on contemporary genetic variation of valley oak (Quercus lobata Née). ENMs indicated that valley oak maintained a stable distribution with local migration from the last interglacial period (~120 ka) to the Last Glacial Maximum (~21 ka, LGM) to the present compared with large-scale range shifts for an eastern North American white oak (Quercus alba L.). Coast Range and Sierra Nevada foothill populations diverged in the late Pleistocene before the LGM [104 ka (28-1622)] and have occupied somewhat distinct climate niches, according to ENMs and coalescent analyses of divergence time. In accordance with neutral expectations for stable populations, nuclear microsatellite diversity positively correlated with niche stability from the LGM to present. Most strikingly, nuclear and chloroplast microsatellite variation significantly correlated with LGM climate, even after controlling for associations with geographic location and present climate using partial redundancy analyses. Variance partitioning showed that LGM climate uniquely explains a similar proportion of genetic variance as present climate (16% vs. 11-18%), and together, past and present climate explains more than geography (19%). Climate can influence local expansion-contraction dynamics, flowering phenology and thus gene flow, and/or impose selective pressures. These results highlight the lingering effect of past climate on genetic variation in species with stable distributions.

  18. Vitamins, stress and growth: the availability of antioxidants in early life influences the expression of cryptic genetic variation.

    PubMed

    Kim, S-Y; Noguera, J C; Tato, A; Velando, A

    2013-06-01

    Environmental inputs during early development can shape the expression of phenotypes, which has long-lasting consequences in physiology and life history of an organism. Here, we study whether experimentally manipulated availability of dietary antioxidants, vitamins C and E, influences the expression of genetic variance for antioxidant defence, endocrine signal and body mass in yellow-legged gull chicks using quantitative genetic models based on full siblings. Our experimental study in a natural population reveals that the expression of genetic variance in total antioxidant capacity in plasma increased in chicks supplemented with vitamins C and E despite the negligible effects on the average phenotype. This suggests that individuals differ in their ability to capture and transport dietary antioxidants or to respond to these extra resources, and importantly, this ability has a genetic basis. Corticosterone level in plasma and body mass were negatively correlated at the phenotypic level. Significant genetic variance of corticosterone level appeared only in control chicks nonsupplemented with vitamins, suggesting that the genetic variation of endocrine system, which transmits environmental cues to adaptively control chick development, appeared in stressful conditions (i.e. poor antioxidant availability). Therefore, environmental inputs may shape evolutionary trajectories of antioxidant capacity and endocrine system by affecting the expression of cryptic genetic variation.

  19. Influence of Atmospheric Variations on Photovoltaic Performance and Modeling Their Effects for Days with Clear Skies: Preprint

    SciTech Connect

    Marion, B.

    2012-06-01

    Although variation in photovoltaic (PV) performance is predominantly influenced by clouds, performance variations also exist for days with clear skies with different amounts of atmospheric constituents that absorb and reflect different amounts of radiation as it passes through the earth's atmosphere. The extent of the attenuation is determined by the mass of air and the amounts of water vapor, aerosols, and ozone that constitute the atmosphere for a particular day and location. Because these constituents selectively absorb radiation of particular wavelengths, their impact on PV performance is sensitive to the spectral response of the PV device. The impact may be assessed by calculating the spectral mismatch correction. This approach was validated using PV module performance data at the National Renewable Energy Laboratory (NREL) for summer, fall, and winter days with clear skies. The standard deviation of daily efficiencies for single-crystal Si, a-Si/a-Si/a-Si:Ge, CdTe, and CIGS PV modules were reduced to 0.4% to 1.0% (relative) by correcting for spectral mismatch, temperature, and angle-of-incidence effects.

  20. Are South Texas Streamflow Variations Influenced by Sea Surface Temperature Changes in Pacific and Atlantic Oceans?

    NASA Astrophysics Data System (ADS)

    Murgulet, V.; Hay, R.; Ard, R.

    2013-12-01

    The impact of sea surface temperature (SST) anomalies of the Pacific and Atlantic Oceans on several major river basins in the continental U. S. has recently become well documented. Clear relationships have been identified between El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO) and continental U. S. streamflow. Because these relationships can be potentially used to predict streamflow variability, it would also be of great importance to evaluate whether these climate phenomena affect river basins at the sub-regional and/or local scale, objectives that are not usually addressed in previous studies. Therefore, this study is focused on the basin river system of South Texas, an area that encompasses approximately 30,000 km2 and is climatologically defined as subtropical subhumid. Streamflow data (1940-2011) from sixteen unimpaired U.S. Geological Survey gage stations were normalized into a South Texas streamflow data set and evaluated with respect to ENSO, PDO and AMO index time series. The comparison of South Texas annual streamflow with Pacific Decadal Oscillation and El Niño Southern Oscillation Indices shows that the warm phases of ENSO and PDO are generally associated with increased streamflow, whereas cold phases of ENSO and PDO result in lower streamflow volumes. In addition, cross-correlation analyses show a 7-8 month delayed streamflow response to sea surface temperature signals. Furthermore, annual streamflow variability in the South Texas river basins can be also due to sea surface temperature anomalies in the Atlantic Ocean. Higher streamflow values are shown during the cold phase of AMO, while relatively low streamflow values are illustrated during the warm phase of AMO. Thus, preliminary results show that SST anomalies in both Pacific and Atlantic Oceans influence the streamflow variability in the South Texas area. Current research is also focused on evaluating if these climate phenomena

  1. Genetic variation influences immune responses in sensitive rats following exposure to TiO2 nanoparticles.

    PubMed

    Gustafsson, Asa; Jonasson, Sofia; Sandström, Thomas; Lorentzen, Johnny C; Bucht, Anders

    2014-12-01

    This study examines the immunological responses in rats following inhalation to titanium dioxide nanoparticles (TiO2 NPs), in naïve rats and in rats with induced allergic airway disease. The responses of two different inbred rat strains were compared: the Dark Aguoti (DA), susceptible to chronic inflammatory disorders, and the Brown Norwegian (BN), susceptible to atopic allergic inflammation. Naïve rats were exposed to an aerosol of TiO2 NPs once daily for 10 days. Another subset of rats was sensitized to the allergen ovalbumin (OVA) in order to induce airway inflammation. These sensitized rats were exposed to TiO2 NPs before and during the allergen challenge. Naïve rats exposed to TiO2 NPs developed an increase of neutrophils and lymphocytes in both rat strains. Airway hyperreactivity and production of inflammatory mediators typical of a T helper 1 type immune response were significantly increased, only in DA rats. Sensitization of the rats induced a prominent OVA-specific-IgE and IgG response in the BN rat while DA rats only showed an increased IgG response. Sensitized rats of both strains developed airway eosinophilia following allergen challenge, which declined upon exposure to TiO2 NPs. The level of neutrophils and lymphocytes increased upon exposure to TiO2 NPs in the airways of DA rats but remained unchanged in the airways of BN rats. In conclusion, the responses to TiO2 NPs were strain-dependent, indicating that genetics play a role in both immune and airway reactivity. DA rats were found to be higher responder compared to BN rats, both when it comes to responses in naïve and sensitized rats. The impact of genetically determined factors influencing the inflammatory reactions pinpoints the complexity of assessing health risks associated with nanoparticle exposures.

  2. Variation in Wildfire Impacts on Vegetation Influences Longterm Recovery of C Stocks Lost to Disturbance

    NASA Astrophysics Data System (ADS)

    Carlson, C. H.; Dobrowski, S. Z.; Safford, H.

    2010-12-01

    Recent studies have used fire behavior and stand growth models to examine how we might use thinning regimes to maximize carbon (C) storage in fire prone forests. Although these studies investigate a number of different forest structures and thinning practices, they model a narrow range of wildfire effects, and do not consider how variability in regeneration and mortality may impact long term C stocks. Mortality and regeneration rates are highly variable within a single fire event, but it is unclear how this variability may impact the time it takes a stand to recover carbon removed during thinning or fire. We use data collected from a natural mixed severity wildfire in the central Sierra Nevada, California to assess the performance of FVS-FFE in predicting carbon transformations due to fire. Secondly we investigate how rates of mortality and tree regeneration, measured over 3 years after fire, impact future estimates of C stocks in thinned and unthinned stands. We perform a sensitivity analysis to assess the importance of mortality and regeneration in controlling the timescales required to restore C stocks lost to disturbance. Mortality rates averaged 30% lower in treated stands; the distribution of mortality rates was skewed towards low and high values, with fewer stands experiencing intermediate rates. Regeneration rates also varied greatly in space and time. Very few seedlings emerged one year after fire, but two thirds of plots had regeneration in year two and three, with densities varying from 30 seedlings ha-1 to over 18,000. Results suggest that model predictions of post-fire carbon accumulation are highly influenced by mortality and regeneration rates.

  3. Genetic Variation of the Alpha Subunit of the Epithelial Na+ Channels Influences Exhaled Na+ in Healthy Humans

    PubMed Central

    Foxx-Lupo, William T.; Wheatley, Courtney M.; Baker, Sarah E.; Cassuto, Nicholas A.; Delamere, Nicholas A.; Snyder, Eric M.

    2011-01-01

    Epithelial Na+ Channels (ENaC) are located on alveolar cells and are important in β2-adrenergic receptor-mediated lung fluid clearance through the removal of Na+ from the alveolar airspace. Previous work has demonstrated that genetic variation of the alpha subunit of ENaC at amino acid 663 is important in channel function: cells with the genotype resulting in alanine at amino acid 663 (A663) demonstrate attenuated function when compared to genotypes with at least one allele encoding threonine (T663, AT/TT). We sought to determine the influence of genetic variation at position 663 of ENaC on exhaled Na+ in healthy humans. Exhaled Na+ was measured in 18 AA and 13 AT/TT subjects (age=27±8 vs. 30±10yrs., ht.=174±12 vs. 171±10cm., wt=68±12 vs. 73±14kg., BMI=22±3 vs. 25±4kg/m2, mean±SD, for AA and AT/TT, respectively). Measurements were made at baseline and at 30, 60 and 90 minutes following the administration of a nebulized β2-agonist (albuterol sulfate, 2.5mg diluted in 3ml normal saline). The AA group had a higher baseline level of exhaled Na+ and a greater response to β2-agonist stimulation (baseline= 3.1±1.8 vs. 2.3±1.5mmol/l; 30min-post= 2.1±0.7 vs. 2.2±0.8mmol/l; 60min-post= 2.0±0.5 vs. 2.3±1.0mmol/l; 90min-post= 1.8±0.8 vs. 2.6±1.5mmol/l, mean±SD, for AA and AT/TT, respectively, p<0.05). The results are consistent with the notion that genetic variation of ENaC influences β2-adrenergic receptor stimulated Na+ clearance in the lungs, as there was a significant reduction in exhaled Na+ over time in the AA group. PMID:21889619

  4. [Distribution, seasonal variation and influence factors of dissolved inorganic arsenic in the Sanggou Bay].

    PubMed

    Li, Lei; Ren, Jing-Ling; Liu, Su-Mei; Jiang, Zeng-Jie; Du, Jin-Zhou; Fang, Jian-Guang

    2014-07-01

    The biogeochemical behavior of arsenic in the aquatic environment has already captured the attentions of scientists due to its complex forms and toxicity. Four cruises were carried out in April, August, October 2011 and January 2012 in the Sanggou Bay. The concentrations of total dissolved inorganic arsenic (TDIAs, TDIAs = [ As(5+] + [As(3+)]) and arsenite (As(3+)) were measured by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS). The concentrations of TDIAs ranged from 3.4-12.4 nmol x L(-1) in April, 8.9-16.9 nmol x L(-1) in August, 14.7-21.3 nmol x L(-1) in October and 13.8-21.9 nmol x L(-1) in January. The concentrations of arsenite ranged from 0.3-2.1 nmol x L(-1), 0.4-3.8 nmol x L(-1), 1.8-4.0 nmol x L(-1) and 0.3-2.9 nmol x L(-1) during four cruises, respectively. The concentrations of TDIAs in spring and summer were lower than those in autumn and winter, and high values of TDIAs appeared in the bay-mouth and the coastal estuary. The concentrations of arsenite in spring and winter were lower than those in summer and autumn. The maximum As(3+)/TDIAs ratios appeared in summer. The mean value of TDIAs in the Sanggou Bay was (13.9 +/- 4.7) nmol x L(-1), which was lower than the national primary drinking in water Standards from USEPA and met the first grade water quality based on the environmental quality standards for surface water of China. It indicates that there is no obvious anthropogenic pollution. The concentrations of TDIAs in the Sanggou Bay were lower than those in the Ailian Bay and the Lidao Bay in spring and summer due to the different hydrological environments and terrestrial inputs. Riverine input, incursion of Yellow Sea and biological activities were the three main factors impacting the distribution of TDIAs in the Sanggou Bay, and the influence of aquaculture activities was particularly significant. The enrichment of arsenic by aquaculture may lead to potential ecological crisis and food safety problems, and need to be paid more

  5. [Distribution, seasonal variation and influence factors of dissolved inorganic arsenic in the Sanggou Bay].

    PubMed

    Li, Lei; Ren, Jing-Ling; Liu, Su-Mei; Jiang, Zeng-Jie; Du, Jin-Zhou; Fang, Jian-Guang

    2014-07-01

    The biogeochemical behavior of arsenic in the aquatic environment has already captured the attentions of scientists due to its complex forms and toxicity. Four cruises were carried out in April, August, October 2011 and January 2012 in the Sanggou Bay. The concentrations of total dissolved inorganic arsenic (TDIAs, TDIAs = [ As(5+] + [As(3+)]) and arsenite (As(3+)) were measured by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS). The concentrations of TDIAs ranged from 3.4-12.4 nmol x L(-1) in April, 8.9-16.9 nmol x L(-1) in August, 14.7-21.3 nmol x L(-1) in October and 13.8-21.9 nmol x L(-1) in January. The concentrations of arsenite ranged from 0.3-2.1 nmol x L(-1), 0.4-3.8 nmol x L(-1), 1.8-4.0 nmol x L(-1) and 0.3-2.9 nmol x L(-1) during four cruises, respectively. The concentrations of TDIAs in spring and summer were lower than those in autumn and winter, and high values of TDIAs appeared in the bay-mouth and the coastal estuary. The concentrations of arsenite in spring and winter were lower than those in summer and autumn. The maximum As(3+)/TDIAs ratios appeared in summer. The mean value of TDIAs in the Sanggou Bay was (13.9 +/- 4.7) nmol x L(-1), which was lower than the national primary drinking in water Standards from USEPA and met the first grade water quality based on the environmental quality standards for surface water of China. It indicates that there is no obvious anthropogenic pollution. The concentrations of TDIAs in the Sanggou Bay were lower than those in the Ailian Bay and the Lidao Bay in spring and summer due to the different hydrological environments and terrestrial inputs. Riverine input, incursion of Yellow Sea and biological activities were the three main factors impacting the distribution of TDIAs in the Sanggou Bay, and the influence of aquaculture activities was particularly significant. The enrichment of arsenic by aquaculture may lead to potential ecological crisis and food safety problems, and need to be paid more

  6. Influence of hydrography of Central Mexican Pacific in the spatial variation of inorganic nutrients during 2010

    NASA Astrophysics Data System (ADS)

    Olivos-Ortiz, A.; Gaviño-Rodríguez, J. H.; Quijano-Scheggia, S.; Pelayo-Martinez, G.; Torres-Orozco, E.; Calva-Chavez, M.

    2014-12-01

    The Mexican Central Pacific (MCP) is considered an oligotrophic area that holds important populations of different species with ecological and economic importance like marine mammals, billfish and tunas. Hydrographic mechanisms are responsible to interplay with the biogeochemical cycles of nutrients to support primary productivity for these food webs. It is argued that seasonal upwelling of bottom waters rich in nutrients generates distributed in patches of high-productivity, which are also linked to topographic continental forcing. The goal of this study is determine the presence of water masses, depth of the mixed layer, temperature, salinity, patterns of geostrophic currents and their influence on the spatiotemporal variability of inorganic nutrients. For that pupose, three oceanographic cruises were conducted in January, May-June, and October of 2010 off the coast of the MCP. Each campaign consisted of 15 stations in five perpendicular transects with stations at 2, 50 and 100 nm offshore. At each station samples were taken to determine the concentration of NO3-+ NO2-, NH4+, PO43- and SiO2 at 0, 10, 25, 50, 75, 100, 150 and 200 m depth. CTD casts were made up to 500m to obtain profiles of salinity, temperature, water masses, and identify geostrophic currents (direction and intensity). Identified water masses were: Pacific Tropical Surface Water (PTSW), Pacific Equatorial Surface Water (PESW), Equatorial Pacific Water (EPW), California Current Water (CCW), Subtropical Subsurface Water (STSsW), and Pacific Intermediate Water (PIT); these water masses were present in all three seasons being more clear the presence of CCW during autumn and PTSW in winter. The interaction between coastal topography, geostrophic circulation, and the depth of the mixed layer (55m oceanic part in January and 10m coastal area in October) were the factors that determined the location of areas of high concentration of nutrients. The distribution of nutrients was heterogeneous

  7. Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and influence of Asian outflows

    NASA Astrophysics Data System (ADS)

    Han, J.; Shin, B.; Lee, M.; Hwang, G.; Kim, J.; Shim, J.; Lee, G.; Shim, C.

    2015-06-01

    Ieodo Ocean Research Station (IORS), a research tower (~ 40 m a.s.l.) for atmospheric and oceanographic observations, is located in the East China Sea (32.07° N, 125.10° E). The IORS is almost equidistant from South Korea, China, and Japan and, therefore, it is an ideal place to observe Asian outflows without local emission effects. The average ozone concentrations were 51.8 ± 15.9 ppbv during June 2003-December 2010. The seasonal variation of ozone was distinct, with a summer minimum (37.8 ppbv) and a spring maximum (61.1 ppbv), and was largely affected by seasonal wind pattern over East Asia. The fractional contribution of ozone at IORS could be attributed to six well distinguished air masses that were classified by the cluster analysis of backward trajectories. Marine air from the Pacific Ocean represents a relatively clean background air with a lowest ozone level of 32.2 ppbv in summer. In spring and winter the influence of Chinese outflows was dominant with higher ozone concentrations of 61.6 and 49.3 ppbv, respectively. This study confirms that the influence of Chinese outflows was the main factor determining O3 levels at IORS, of which extent was apt to be changed by meteorological state, particularly at a long-term scale.

  8. Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows

    NASA Astrophysics Data System (ADS)

    Han, J.; Shin, B.; Lee, M.; Hwang, G.; Kim, J.; Shim, J.; Lee, G.; Shim, C.

    2015-11-01

    Ieodo Ocean Research Station (IORS), a research tower (~ 40 m a.s.l.) for atmospheric and oceanographic observations, is located in the East China Sea (32.07° N, 125.10° E). The IORS is almost equidistant from South Korea, China, and Japan and, therefore, it is an ideal place to observe Asian outflows without local emission effects. The seasonal variation of ozone was distinct, with a minimum in August (37 ppbv) and two peaks in April and October (62 ppbv), and was largely affected by the seasonal wind pattern over east Asia. At IORS, six types of air masses were distinguished with different levels of O3 concentrations by the cluster analysis of backward trajectories. Marine air masses from the Pacific Ocean represent a relatively clean background air with a lowest ozone level of 32 ppbv, which was most frequently observed in summer (July-August). In spring (March-April) and winter (December-February), the influence of Chinese outflows was dominant with higher ozone concentrations of 62 and 49 ppbv, respectively. This study confirms that the influence of Chinese outflows was the main factor determining O3 levels at IORS and its extent was dependent on meteorological state, particularly at a long-term scale.

  9. Climate effects on volcanism: influence on magmatic systems of loading and unloading from ice mass variations, with examples from Iceland.

    PubMed

    Sigmundsson, Freysteinn; Pinel, Virginie; Lund, Björn; Albino, Fabien; Pagli, Carolina; Geirsson, Halldór; Sturkell, Erik

    2010-05-28

    Pressure influences both magma production and the failure of magma chambers. Changes in pressure interact with the local tectonic settings and can affect magmatic activity. Present-day reduction in ice load on subglacial volcanoes due to global warming is modifying pressure conditions in magmatic systems. The large pulse in volcanic production at the end of the last glaciation in Iceland suggests a link between unloading and volcanism, and models of that process can help to evaluate future scenarios. A viscoelastic model of glacio-isostatic adjustment that considers melt generation demonstrates how surface unloading may lead to a pulse in magmatic activity. Iceland's ice caps have been thinning since 1890 and glacial rebound at rates exceeding 20 mm yr(-1) is ongoing. Modelling predicts a significant amount of 'additional' magma generation under Iceland due to ice retreat. The unloading also influences stress conditions in shallow magma chambers, modifying their failure conditions in a manner that depends critically on ice retreat, the shape and depth of magma chambers as well as the compressibility of the magma. An annual cycle of land elevation in Iceland, due to seasonal variation of ice mass, indicates an annual modulation of failure conditions in subglacial magma chambers.

  10. Flooding of lignite mines: isotope variations and processes in a system influenced by saline groundwater.

    PubMed

    Trettin, Rolf; Glässer, Walter; Lerche, Ian; Seelig, Ulrike; Treutler, Hanns-Christian

    2006-06-01

    The quality of both groundwaters and surface waters that arise during flooding of abandoned lignite open pits are influenced by regional and local factors. A typical regional factor is due to oxidised sedimentary sulfides. A more local factor is the interaction of shallow water with highly saline groundwater, which is important in Merseburg-Ost (Germany). Investigation of this system is aided by the use of many environmental isotope tracers but special problems can arise. In order to reveal processes in the mine environment (shallow groundwater, lake water) and to characterise mixtures with saline groundwater results are described using the tracers deltaD, delta18O, delta13C, delta34S, 87Sr/86Sr, 3H, 14C, 39Ar, and 222Rn. Deep highly saline groundwater had a radiocarbon concentration typically below 10 pMC. The values of delta13C(DIC) are around-5 per thousand. As delta13C of the aquifer rock samples (Permian, Zechstein carbonates) was in the range of-6...+5 per thousand, residence time corrections based on delta13C are questionable. Additional checks with 39Ar, as well as results from the variationof delta18O (or deltaD) with respect to the salinity, emphasise a Holocene age; as is also the case for most mineralised groundwaters and also for water having a low delta18O (and deltaD). For saline groundwater residing in the Zechstein aquifer the measured delta34S values of about 12 per thousand are close to those expected from the literature. In contrast, the 87Sr/86Sr ratio of dissolved strontium is far from the values anticipated for the aquifer rocks despite there being proportionality between the chloride concentration and the strontium concentration. Furthermore, the proportionality is not valid in lower mineralised water. The 87Sr/86Sr ratio can, therefore, hardly be used as a tracer for the distribution of ascending saline water. The amount of salt-water coming from below into the residual quarry basins is an essential contribution to the lake inventories

  11. Belled end fittings: A recently qualified, high strength, low cost, and production friendly welded fitting design

    SciTech Connect

    Bayard, R.R.; Oakes, F.D. Jr.

    1996-07-01

    This paper presents an overview of the design development, fatigue testing, MSS Standard Practice development and Navy shipboard use of light wall (Schedule 10) socket welded cold formed fittings designed to replace B16.9 type butt welded fittings in sizes 1/4 through 12 NPS. Variations of the belled end fitting design have been successfully used -- thus proven in service -- for almost 40 years. This Government-sponsored program has legitimized the fittings by laboratory testing, has standardized the fittings by Standard Practice publication and has given the fittings a market presence by acceptance on Navy ship new construction and repair.

  12. Partnerships for the Fit.

    ERIC Educational Resources Information Center

    Golding, Lawrence A.

    1984-01-01

    The YMCA has helped train and employ fitness leaders while educating the public on physical fitness. Colleges and universities can help develop careers in fitness while maintaining their traditional role of developing teachers and coaches. (DF)

  13. The influence of the internalization of emotional regulation on mental health among the Taiwanese people: the moderating effect of cultural fit.

    PubMed

    Chu, Li-Chuan

    2015-03-01

    This study used a 2-stage questionnaire survey to explore whether self-regulation by withholding negative emotions (SRWNE) affects mental health and examines further whether cultural fit can moderate the relationship between SRWNE and mental health. The 2-stage studies used data collected from 405 (time 1) and 313 (time 2) full-time staff employed by private and public enterprises in Taiwan. The author tested hypotheses through the use of hierarchical multiple regression. The results showed that controlled SRWNE through external regulation and introjected regulation is significantly associated positively with somatic symptoms, anxiety and insomnia, social dysfunction, and severe depression, whereas autonomous SRWNE through identified regulation is significantly associated negatively with anxiety and insomnia, and social dysfunction. In addition, this study also found that cultural fit may moderate the relationship between SRWNE or introjected regulation and identified regulation and the mental health indicators.

  14. Reading fitness landscape diagrams through HSAB concepts

    NASA Astrophysics Data System (ADS)

    Vigneresse, Jean-Louis

    2014-10-01

    Fitness landscapes are conceived as range of mountains, with local peaks and valleys. In terms of potential, such topographic variations indicate places of local instability or stability. The chemical potential, or electronegativity, its value changed of sign, carries similar information. In addition to chemical descriptors defined through hard-soft acid-base (HSAB) concepts and computed through density functional theory (DFT), the principles that rule chemical reactions allow the design of such landscape diagrams. The simplest diagram uses electrophilicity and hardness as coordinates. It allows examining the influence of maximum hardness or minimum electrophilicity principles. A third dimension is introduced within such a diagram by mapping the topography of electronegativity, polarizability or charge exchange. Introducing charge exchange during chemical reactions, or mapping a third parameter (f.i. polarizability) reinforces the information carried by a simple binary diagram. Examples of such diagrams are provided, using data from Earth Sciences, simple oxides or ligands.

  15. Response of Foot-and-Mouth Disease Virus to Increased Mutagenesis: Influence of Viral Load and Fitness in Loss of Infectivity

    PubMed Central

    Sierra, Saleta; Dávila, Mercedes; Lowenstein, Pedro R.; Domingo, Esteban

    2000-01-01

    Passage of foot-and-mouth disease virus (FMDV) in cell culture in the presence of the mutagenic base analog 5-fluorouracil or 5-azacytidine resulted in decreases of infectivity and occasional extinction of the virus. Low viral loads and low viral fitness enhanced the frequency of extinction events; this finding was shown with a number of closely related FMDV clones and populations differing by up to 106-fold in relative fitness in infections involving either single or multiple passages in the absence or presence of the chemical mutagens. The mutagenic treatments resulted in increases of 2- to 6.4-fold in mutation frequency and up to 3-fold in mutant spectrum complexity. The largest increase observed corresponded to the 3D (polymerase)-coding region, which is highly conserved in nonmutagenized FMDV populations. As a result, nucleotide sequence heterogeneity for the 3D-coding region became very similar to that for the variable VP1-coding region in FMDVs multiply passaged in the presence of chemical mutagens. The results suggest that strategies to combine reductions of viral load and viral fitness could be effectively associated with extinction mutagenesis as a potential new antiviral strategy. PMID:10954530

  16. Herbivory strongly influences among-population variation in reproductive output of Lythrum salicaria in its native range.

    PubMed

    Lehndal, Lina; Hambäck, Peter A; Ericson, Lars; Ågren, Jon

    2016-04-01

    Herbivory can negatively affect several components of plant reproduction. Yet, because of a lack of experimental studies involving multiple populations, the extent to which differences in herbivory contribute to among-population variation in plant reproductive success is poorly known. We experimentally determined the effects of insect herbivory on reproductive output in nine natural populations of the perennial herb Lythrum salicaria along a disturbance gradient in an archipelago in northern Sweden, and we quantified among-population differentiation in resistance to herbivory in a common-garden experiment in the same area. The intensity of leaf herbivory varied >500-fold and mean female reproductive success >400-fold among the study populations. The intensity of herbivory was lowest in populations subject to strong disturbance from ice and wave action. Experimental removal of insect herbivores showed that the effect of herbivory on female reproductive success was correlated with the intensity of herbivory and that differences in insect herbivory could explain much of the among-population variation in the proportion of plants flowering and seed production. Population differentiation in resistance to herbivory was limited. The results demonstrate that the intensity of herbivory is a major determinant of flowering and seed output in L. salicaria, but that differences in herbivory are not associated with differences in plant resistance at the spatial scale examined. They further suggest that the physical disturbance regime may strongly influence the performance and abundance of perennial herbs and patterns of selection not only because of its effect on interspecific competition, but also because of effects on interactions with specialized herbivores.

  17. Leucine-responsive regulatory protein Lrp and PapI homologues influence phase variation of CS31A fimbriae.

    PubMed

    Graveline, Richard; Garneau, Philippe; Martin, Christine; Mourez, Michaël; Hancock, Mark A; Lavoie, Rémi; Harel, Josée

    2014-08-15

    CS31A, a K88-related surface antigen specified by the clp operon, is a member of the type P family of adhesive factors and plays a key role in the establishment of disease caused by septicemic and enterotoxigenic Escherichia coli strains. Its expression is under the control of methylation-dependent transcriptional regulation, for which the leucine-responsive regulatory protein (Lrp) is essential. CS31A is preferentially in the OFF state and exhibits distinct regulatory features compared to the regulation of other P family members. In the present study, surface plasmon resonance and DNase I protection assays showed that Lrp binds to the distal moiety of the clp regulatory region with low micromolar affinity compared to its binding to the proximal moiety, which exhibits stronger, nanomolar affinity. The complex formation was also influenced by the addition of PapI or FooI, which increased the affinity of Lrp for the clp distal and proximal regions and was required to induce phase variation. The influence of PapI or FooI, however, was predominantly associated with a more complete shutdown of clp expression, in contrast to what has previously been observed with AfaF (a PapI ortholog). Taken together, these results suggest that the preferential OFF state observed in CS31A cells is mainly due to the weak interaction of the leucine-responsive regulatory protein with the clp distal region and that the PapI homolog favors the OFF phase. Within the large repertoire of fimbrial variants in the P family, our study illustrates that having a fimbrial operon that lacks its own PapI ortholog allows it to be more flexibly regulated by other orthologs in the cell. PMID:24914179

  18. ON THE INFLUENCE OF COLD WORK ON RESISTIVITY VARIATIONS WITH THERMAL EXPOSURE IN IN-718 NICKEL-BASE SUPERALLOY

    SciTech Connect

    Madhi, Elhoucine; Nagy, Peter B.

    2010-02-22

    In nickel-base superalloys, irreversible electrical conductivity changes occur above a transition temperature where thermally-activated microstructural evolution initiates. The electrical conductivity first decreases above about 450 deg. C then increases above 600 deg. C. However, the presence of plastic deformation results in accelerated microstructure evolution at an earlier transition temperature. It was recently suggested that this well-known phenomenon might explain the notable conductivity difference between the peened near-surface part and the intact part at sufficiently large depth in surface-treated specimens. The influence of cold work on the electrical conductivity change with thermal exposure offers a probable answer to one of the main remaining questions in eddy current residual stress assessment, namely unusually fast and occasionally even non-monotonic decay of the apparent eddy current conductivity (AECC) change that was observed at temperatures as low as 400 deg. C. To validate this explanation, the present study investigates the influence of cold work on low-frequency Alternating Current Potential Drop (ACPD) resistivity variations with thermal exposure. In-situ resistivity monitoring was conducted throughout various heating cycles using the ACPD technique. IN-718 nickel-base superalloy specimens with different levels of cold work were exposed to gradually increasing peak temperatures from 400 deg. C to 800 deg. C. The results indicate that the initial irreversible rise in resistivity is approximately one order of magnitude higher and occurs at about 50 deg. C lower temperature in cold-worked samples of 30% plastic strain than in the intact material.

  19. Influence of tidal variation and wave forcing on shallow groundwater discharge to the sea adjoining the Bay of Bengal, India

    NASA Astrophysics Data System (ADS)

    Debnath, P.; Mukherjee, A.; Gujral, K. S.

    2015-12-01

    Tidal fluctuation and wave pumping control the groundwater discharge and solute transport from the coastal aquifers to the sea. This discharged groundwater and solute flux could cause significant geochemical evolution at the groundwater-seawater (GW-SW) interaction zone, and have a potential impact on marine ecosystems. In this study we have tried to trace these tidal influences on discharging groundwater flow path and its quality at the Bay of Bengal, India by using numerical modelling. We have done multi-season time-series sea-bed porewater sampling from nested wells throughout a tidal cycle, along with groundwater sampling from the tube-wells in the vicinity, aquifer parameter estimation and beach geomorphology, to delineate the variations of solute chemistry within a tidal cycle. Numerical modelled data suggest that the tidal pumping at the study area leads seawater intrusion in the backshore aquifers. The local geology and low beach slope (<1°) also accentuate this phenomenon. The salinity of porewater at a specific well was found to vary temporally along tidal cycle, from being highest at the start of high tide and lowest during a low tide period. Time series analysis of chemical characteristics of the samples depicts that tidal fluctuation on a diurnal-scale significantly affects the ionic composition of the discharged groundwater along with piezometric level for unconfined aquifer. Graphical geochemical plots suggest that ionic exchanges at GW-SW interaction zone along with redox cycles are likely to be the main processes responsible for water quality changes. These findings highlight the significant influence of tidal fluctuations and wave pumping on discharged groundwater quality and groundwater-seawater hydrodynamics in the coastal areas.

  20. Potential Influence of Arctic Sea Ice to the Inter-annual Variations of East Asian Spring Precipitation

    NASA Astrophysics Data System (ADS)

    Li, Xinxin; Wu, Zhiwei; Li, Yanjie

    2016-04-01

    Arctic sea ice (ASI) and its potential climatic impacts have received increasing attention during the past decades, yet the relevant mechanisms are far from being understood, particularly on how anomalous ASI affects climate in midlatitudes. The spring precipitation takes up as much as 30% of the annual total and has significant influences to agriculture in East Asia. Here, observed evidence and numerical experiment results manifest that the ASI variability in the Norwegian Sea and the Barents Sea in preceding winter is intimately connected with interannual variations of the East Asian spring precipitation (EAP). The former can explain about 14% of the total variances of the latter. The ASI anomalies persist from winter through the ensuing spring and excite downstream tele-connections of a distinct Rossby wave train prevailing over the Eurasian continent. For the reduced ASI, such a wave train pattern is usually associated with an anomalous low pressure center over Mongolian Plateau, which accelerates the East Asian subtropical westerly jet. The intensified subtropical westerly jet, concurrent with lower-level convergence and upper-level divergence, enhances the local convection and consequently favors rich spring precipitation over East Asia. For the excessive ASI, the situation tends to be opposite. Given that seasonal prediction of the EAP remains a challenging issue, the winter ASI variability may provide another potential predictability source besides El Niño-Southern Oscillation.

  1. Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste.

    PubMed

    Jin, Rong; Zhan, Jiayu; Liu, Guorui; Zhao, Yuyang; Zheng, Minghui

    2016-09-01

    Pilot studies of unintentionally produced pollutants should be performed before waste being co-processed in cement kilns. Polychlorinated naphthalene (PCN) formation and emission from cement kilns co-processing sorted municipal solid waste, sewage sludge, and waste acid, however, have not previously been studied. Here, PCNs were analyzed in stack gas samples and solid samples from different stages of three cement production runs. PCN destruction efficiencies were higher when waste was co-processed (93.1% and 88.7% in two tests) than when waste was not co-processed (39.1%), so co-processing waste would not increase PCN outputs. The PCN concentrations were higher in particle samples from the C1 preheater and stages at back end of kiln than in particle samples from other stages, suggesting that cyclone preheater and back end of kiln should be focused for controlling PCN emissions. Besides that, based on the variation of PCN concentrations and corresponding operating conditions in different stages, the temperature, feeding materials, and chlorine content were suggested as the main factors influencing PCN formation. The PCN homologue and congener profiles suggested chlorination and dechlorination were the main PCN formation and decomposition pathways, and congeners CN-23, CN-46, and CN-59 appear to be appropriate indicators of PCNs emitted from coal-burning sources.

  2. Expression of stemness markers in mouse parthenogenetic-diploid blastocysts is influenced by slight variation of activation protocol adopted.

    PubMed

    Bianchi, Enrica; Geremia, Raffaele; Sette, Claudio

    2010-07-01

    The importance of obtaining stem cells through alternative methods has increased progressively in the recent years due to the potential role that embryonic stem (ES) cells play in the field of regenerative medicine. In this regard, generation of parthenogenetic blastocysts allows the production of ethic-free ES cells without the need to manipulate normal embryos. Our work was aimed at clarifying whether variations in the method adopted to generate diploid parthenogenetic blastocysts could determine differences in the quality of blastocysts produced. In vitro development of mouse oocytes activated with three protocols, using Sr2+ and cytochalasin for different time, was compared with that of in vivo fertilized embryos. We have evaluated the efficiency of blastocyst formation and analysed the expression pattern of the stemness markers OCT4, CDX2, and NANOG. Our results indicate that the yield of diploid parthenogenotes and the segregation of the stemness marker OCT4 in the developing blastocyst are influenced by the parthenogenetic protocol adopted. Particularly, even if all methods tested allowed the production of blastocysts in vitro, the correct segregation of OCT4 occurred only in blastocysts developed from oocytes concomitantly treated for 4 h with Sr2+ and cytochalasin D. Our results indicate that the protocol employed to develop parthenogenetic blastocysts in vitro affects the quality of cells in the inner cell mass.

  3. Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste.

    PubMed

    Jin, Rong; Zhan, Jiayu; Liu, Guorui; Zhao, Yuyang; Zheng, Minghui

    2016-09-01

    Pilot studies of unintentionally produced pollutants should be performed before waste being co-processed in cement kilns. Polychlorinated naphthalene (PCN) formation and emission from cement kilns co-processing sorted municipal solid waste, sewage sludge, and waste acid, however, have not previously been studied. Here, PCNs were analyzed in stack gas samples and solid samples from different stages of three cement production runs. PCN destruction efficiencies were higher when waste was co-processed (93.1% and 88.7% in two tests) than when waste was not co-processed (39.1%), so co-processing waste would not increase PCN outputs. The PCN concentrations were higher in particle samples from the C1 preheater and stages at back end of kiln than in particle samples from other stages, suggesting that cyclone preheater and back end of kiln should be focused for controlling PCN emissions. Besides that, based on the variation of PCN concentrations and corresponding operating conditions in different stages, the temperature, feeding materials, and chlorine content were suggested as the main factors influencing PCN formation. The PCN homologue and congener profiles suggested chlorination and dechlorination were the main PCN formation and decomposition pathways, and congeners CN-23, CN-46, and CN-59 appear to be appropriate indicators of PCNs emitted from coal-burning sources. PMID:27187059

  4. Expression of stemness markers in mouse parthenogenetic-diploid blastocysts is influenced by slight variation of activation protocol adopted.

    PubMed

    Bianchi, Enrica; Geremia, Raffaele; Sette, Claudio

    2010-07-01

    The importance of obtaining stem cells through alternative methods has increased progressively in the recent years due to the potential role that embryonic stem (ES) cells play in the field of regenerative medicine. In this regard, generation of parthenogenetic blastocysts allows the production of ethic-free ES cells without the need to manipulate normal embryos. Our work was aimed at clarifying whether variations in the method adopted to generate diploid parthenogenetic blastocysts could determine differences in the quality of blastocysts produced. In vitro development of mouse oocytes activated with three protocols, using Sr2+ and cytochalasin for different time, was compared with that of in vivo fertilized embryos. We have evaluated the efficiency of blastocyst formation and analysed the expression pattern of the stemness markers OCT4, CDX2, and NANOG. Our results indicate that the yield of diploid parthenogenotes and the segregation of the stemness marker OCT4 in the developing blastocyst are influenced by the parthenogenetic protocol adopted. Particularly, even if all methods tested allowed the production of blastocysts in vitro, the correct segregation of OCT4 occurred only in blastocysts developed from oocytes concomitantly treated for 4 h with Sr2+ and cytochalasin D. Our results indicate that the protocol employed to develop parthenogenetic blastocysts in vitro affects the quality of cells in the inner cell mass. PMID:20376706

  5. Influence of carbon and lipid sources on variation of mercury and other trace elements in polar bears (Ursus maritimus).

    PubMed

    Routti, Heli; Letcher, Robert J; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; McKinney, Melissa A; Peacock, Elizabeth; Sonne, Christian

    2012-12-01

    In the present study, the authors investigated the influence of carbon and lipid sources on regional differences in liver trace element (As, Cd, Cu, total Hg, Mn, Pb, Rb, Se, and Zn) concentrations measured in polar bears (Ursus maritimus) (n = 121) from 10 Alaskan, Canadian Arctic, and East Greenland subpopulations. Carbon and lipid sources were assessed using δ(13) C in muscle tissue and fatty acid (FA) profiles in subcutaneous adipose tissue as chemical tracers. A negative relationship between total Hg and δ(13) C suggested that polar bears feeding in areas with higher riverine inputs of terrestrial carbon accumulate more Hg than bears feeding in areas with lower freshwater input. Mercury concentrations were also positively related to the FA 20:1n-9, which is biosynthesized in large amounts in Calanus copepods. This result raises the hypothesis that Calanus glacialis are an important link in the uptake of Hg in the marine food web and ultimately in polar bears. Unadjusted total Hg, Se, and As concentrations showed greater geographical variation among polar bear subpopulations compared with concentrations adjusted for carbon and lipid sources. The Hg concentrations adjusted for carbon and lipid sources in Bering-Chukchi Sea polar bear liver tissue remained the lowest among subpopulations. Based on these findings, the authors suggest that carbon and lipid sources for polar bears should be taken into account when one is assessing spatial and temporal trends of long-range transported trace elements.

  6. A Pretty Good Fit

    ERIC Educational Resources Information Center

    Erickson, Tim

    2008-01-01

    We often look for a best-fit function to a set of data. This article describes how a "pretty good" fit might be better than a "best" fit when it comes to promoting conceptual understanding of functions. In a pretty good fit, students design the function themselves rather than choosing it from a menu; they use appropriate variable names; and they…

  7. Physical Fitness Assessment.

    ERIC Educational Resources Information Center

    Valdes, Alice

    This document presents baseline data on physical fitness that provides an outline for assessing the physical fitness of students. It consists of 4 tasks and a 13-item questionnaire on fitness-related behaviors. The fitness test evaluates cardiorespiratory endurance by a steady state jog; muscular strength and endurance with a two-minute bent-knee…

  8. An Evaluation of the Significance of Work-Related Influence Factors on Fitness and the Development of Medical and Orthopaedic Conditions in Military Executives

    PubMed Central

    Becker, Michael; Finze, Susanne; Holtherm, Christoph; Hinder, Jens; Lison, Andreas

    2016-01-01

    Occupational health promotion is an effective tool to improve the state of health of employees. As part of occupational health promotion in the German Bundeswehr, top-ranking military executives are offered a medical examination and training programme. Health-related data is collected as a basis for training and lifestyle counselling. This data was subjected to a retrospective evaluation in order to identify occupational risk factors and their correlation with cardiovascular resilience, trunk strength, and the development of orthopaedic and internal disorders. A total of 122 military executives (all male, age 54.6 ± 4.2 years) answered a questionnaire aimed at evaluating private and occupational stress factors. The medical history was followed by a medical and orthopaedic examination involving a lactate performance test (treadmill or bicycle ergometry) and an isometric trunk strength measurement. The data obtained was then statistically evaluated. For military executives, work-related travelling and commuting involve a high risk of medical and orthopaedic conditions. Regular exercise leads to improved fitness levels. In order to prevent medical problems, military executives working long hours should regularly take part in fitness and weight training under professional instructions. PMID:27774505

  9. An ethnographic exploration of influences on prescribing in general practice: why is there variation in prescribing practices?

    PubMed Central

    2013-01-01

    Background Prescribing is a core activity for general practitioners, yet significant variation in the quality of prescribing has been reported. This suggests there may be room for improvement in the application of the current best research evidence. There has been substantial investment in technologies and interventions to address this issue, but effect sizes so far have been small to moderate. This suggests that prescribing is a decision-making process that is not sufficiently understood. By understanding more about prescribing processes and the implementation of research evidence, variation may more easily be understood and more effective interventions proposed. Methods An ethnographic study in three Scottish general practices with diverse organizational characteristics. Practices were ranked by their performance against Audit Scotland prescribing quality indicators, incorporating established best research evidence. Two practices of high prescribing quality and one practice of low prescribing quality were recruited. Participant observation, formal and informal interviews, and a review of practice documentation were employed. Results Practices ranked as high prescribing quality consistently made and applied macro and micro prescribing decisions, whereas the low-ranking practice only made micro prescribing decisions. Macro prescribing decisions were collective, policy decisions made considering research evidence in light of the average patient, one disease, condition, or drug. Micro prescribing decisions were made in consultation with the patient considering their views, preferences, circumstances and other conditions (if necessary). Although micro prescribing can operate independently, the implementation of evidence-based, quality prescribing was attributable to an interdependent relationship. Macro prescribing policy enabled prescribing decisions to be based on scientific evidence and applied consistently where possible. Ultimately, this influenced prescribing

  10. SU-E-I-96: A Study About the Influence of ROI Variation On Tumor Segmentation in PET

    SciTech Connect

    Li, L; Tan, S; Lu, W; D'Souza, W

    2014-06-01

    Purpose: To study the influence of different regions of interest (ROI) on tumor segmentation in PET. Methods: The experiments were conducted on a cylindrical phantom. Six spheres with different volumes (0.5ml, 1ml, 6ml, 12ml, 16ml and 20 ml) were placed inside a cylindrical container to mimic tumors of different sizes. The spheres were filled with 11C solution as sources and the cylindrical container was filled with 18F-FDG solution as the background. The phantom was continuously scanned in a Biograph-40 True Point/True View PET/CT scanner, and 42 images were reconstructed with source-to-background ratio (SBR) ranging from 16:1 to 1.8:1. We took a large and a small ROI for each sphere, both of which contain the whole sphere and does not contain any other spheres. Six other ROIs of different sizes were then taken between the large and the small ROI. For each ROI, all images were segmented by eitht thresholding methods and eight advanced methods, respectively. The segmentation results were evaluated by dice similarity index (DSI), classification error (CE) and volume error (VE). The robustness of different methods to ROI variation was quantified using the interrun variation and a generalized Cohen's kappa. Results: With the change of ROI, the segmentation results of all tested methods changed more or less. Compared with all advanced methods, thresholding methods were less affected by the ROI change. In addition, most of the thresholding methods got more accurate segmentation results for all sphere sizes. Conclusion: The results showed that the segmentation performance of all tested methods was affected by the change of ROI. Thresholding methods were more robust to this change and they can segment the PET image more accurately. This work was supported in part by National Natural Science Foundation of China (NNSFC), under Grant Nos. 60971112 and 61375018, and Fundamental Research Funds for the Central Universities, under Grant No. 2012QN086. Wei Lu was supported in

  11. Influence of seasonal variation on water quality in tropical water distribution system: is the disease burden significant?

    PubMed

    Etchie, Ayotunde T; Etchie, Tunde O; Adewuyi, Gregory O; Kannan, Krishnamurthi; Wate, Satish R; Sivanesan, Saravanadevi; Chukwu, Angela U

    2014-02-01

    Recent evidence shows that water distribution system (WDS) is a major risk factor in piped water supply system and the degree of contamination of water in WDS is usually influenced by seasonal variation. Risk assessment studies eliminate the effect of seasonality whenever annualized estimate of concentration of contaminants in water is used to determine the risk to health. In tropical climate where strong seasonal variation prevails, the excess risk during dry and hot season, above the annualized risk can be significant. This study investigates what impact seasonal adjustment may have on health improvement targets for WDS. Water quality data of two Nigerian water supply schemes were used to estimate the impact of WDS on water quality. Seasonal deviation from the annualized impact was quantified as the latent risk in disability-adjusted life years (DALYs). The hazards identified in both WDSs were cadmium and lead, and the estimated 95th-percentile risk of the metals, over the course of dry season was about 31-38%, and 1-3% higher than the estimated yearly average risk, respectively. Wilcoxon signed-rank test showed that the risk distributions during the dry season was significantly higher (p < 0.05) than the yearly average. The median latent risks (5th, 95th-percentiles), for both WDS were 0.014 (7.6 × 10(-3), 0.023) and 4.8 × 10(-3) (-, 7.6 × 10(-3)) DALYs/person/year for cadmium and 0.87 × 10(-3) (0, 0.1 × 10(-3)) and 0.16 × 10(-3) (0, 0.031 × 10(-3)) DALYs/person/year, respectively, for lead. These risks are substantially higher than the WHO limit (1 × 10(-6) DALYs/person/year). Therefore, to achieve effective health improvement target, mitigation measures should be planned and executed by season.

  12. Fitting in or opting out: A review of key social-psychological factors influencing a sense of belonging for women in physics

    NASA Astrophysics Data System (ADS)

    Lewis, Karyn L.; Stout, Jane G.; Pollock, Steven J.; Finkelstein, Noah D.; Ito, Tiffany A.

    2016-12-01

    [This paper is part of the Focused Collection on Gender in Physics.] A number of cultural, social, environmental, and biological factors have been suggested to explain women's relatively lower representation in physics and other science, technology, engineering, and math (STEM) fields. Given its persistence, the causes of gender disparities are likely to be complex and multiply determined. In this review paper, we discuss how a sense of belonging relates to women's interest, persistence, and achievement in physics. We explore what it means to "fit in" and belong in academic contexts, the situational and interpersonal antecedents to belonging, and the consequences of a lack of belonging. We review the empirical evidence for the efficacy of interventions designed to bolster a sense of belonging. Based on these interventions we conclude the paper with a number of practical recommendations to affirm women's sense of belonging and create more welcoming and inclusive physics environments for all students.

  13. [Diurnal and Seasonal Dynamic Variation of Soil Respiration and Its Influencing Factors of Different Fenced Enclosure Years in Desert Steppec].

    PubMed

    Cui, Hai; Zhang, Ya-hong

    2016-04-15

    The fenced measures could improve the ecological environment of degraded grassland, it's a main measure for restoration of degraded grassland vegetation in China. Soil respiration (Rs) is an important component of an ecosystem's carbon cycle and the main pathway for carbon moving from the ecosystem to the atmosphere. In order to explore soil respiration characteristics and influencing factors of the different fenced years in arid desert grassland, we continuously observed Rs rate and environmental factors in the growing season of fenced enclosure 11a, 7a and no fenced (CK) desert steppe in Ningxia. The results showed that: (1) Both the diurnal andseasonal variations of Rs rate showed a single asymmetric peak changing in fenced enclosure of 11 years, 7 years, CK desert steppe. On the daily scale, the maximum and minimum values of Rs rate were found in the periods of 12:00-16:00 and 00:00-06:00,respectively. On the seasonal variation scale, the maximum value of Rs rate occurred in August with suitable precipitation and temperature conditions. And the Rs rate of the growing season of different fenced enclosure years was in the order of 11a [0.143 g · (m² · h)⁻¹] > 7a [0.138 g · (m² · h)⁻¹] > CK [0.106 g · (m2 - h)⁻¹]. (2) According to statistical analysis, it indicated that R² rate had a significant exponential positive relationship with air and soil temperature in fenced enclosure of 11 years, 7 years, CK desert steppe (P < 0.01). The order of the correlation of Rs rate and temperature was shown as soil surface temperature (R²: 0.408-0.413) > air temperature (R2: 0.355-0.376) > 5-20 cm soil temperature (R2: 0.263-0.394). The temperature sensitivity coefficient Q, increased gradually with the soil depth, and Q1, of different fenced enclosure years was showed as 11 a (2.728) > 7a (2.436) > CK (2.086). (3) A significant quadratic function model (P < 0.05) was observed for the relationship between Rs rate and relative air humidity, soil moisture content

  14. [Diurnal and Seasonal Dynamic Variation of Soil Respiration and Its Influencing Factors of Different Fenced Enclosure Years in Desert Steppec].

    PubMed

    Cui, Hai; Zhang, Ya-hong

    2016-04-15

    The fenced measures could improve the ecological environment of degraded grassland, it's a main measure for restoration of degraded grassland vegetation in China. Soil respiration (Rs) is an important component of an ecosystem's carbon cycle and the main pathway for carbon moving from the ecosystem to the atmosphere. In order to explore soil respiration characteristics and influencing factors of the different fenced years in arid desert grassland, we continuously observed Rs rate and environmental factors in the growing season of fenced enclosure 11a, 7a and no fenced (CK) desert steppe in Ningxia. The results showed that: (1) Both the diurnal andseasonal variations of Rs rate showed a single asymmetric peak changing in fenced enclosure of 11 years, 7 years, CK desert steppe. On the daily scale, the maximum and minimum values of Rs rate were found in the periods of 12:00-16:00 and 00:00-06:00,respectively. On the seasonal variation scale, the maximum value of Rs rate occurred in August with suitable precipitation and temperature conditions. And the Rs rate of the growing season of different fenced enclosure years was in the order of 11a [0.143 g · (m² · h)⁻¹] > 7a [0.138 g · (m² · h)⁻¹] > CK [0.106 g · (m2 - h)⁻¹]. (2) According to statistical analysis, it indicated that R² rate had a significant exponential positive relationship with air and soil temperature in fenced enclosure of 11 years, 7 years, CK desert steppe (P < 0.01). The order of the correlation of Rs rate and temperature was shown as soil surface temperature (R²: 0.408-0.413) > air temperature (R2: 0.355-0.376) > 5-20 cm soil temperature (R2: 0.263-0.394). The temperature sensitivity coefficient Q, increased gradually with the soil depth, and Q1, of different fenced enclosure years was showed as 11 a (2.728) > 7a (2.436) > CK (2.086). (3) A significant quadratic function model (P < 0.05) was observed for the relationship between Rs rate and relative air humidity, soil moisture content

  15. Variation in migratory behavior influences regional genetic diversity and structure among American Kestrel populations (Falco sparverius) in North America.

    PubMed

    Miller, Mark P; Mullins, Thomas D; Parrish, John W; Walters, Jeffrey R; Haig, Susan M

    2012-07-01

    Birds employ numerous strategies to cope with seasonal fluctuations in high-quality habitat availability. Long distance migration is a common tactic; however, partial migration is especially common among broadly distributed species. Under partial migration systems, a portion of a species migrates, whereas the remainder inhabits breeding grounds year round. In this study, we identified effects of migratory behavior variation on genetic structure and diversity of American Kestrels (Falco sparverius), a widespread partial migrant in North America. American Kestrels generally migrate; however, a resident group inhabits the southeastern United States year round. The southeastern group is designated as a separate subspecies (F. s. paulus) from the migratory group (F. s. sparverius). Using mitochondrial DNA and microsatellites from 183 and 211 individuals, respectively, we illustrate that genetic structure is stronger among nonmigratory populations, with differentiation measures ranging from 0.060 to 0.189 depending on genetic marker and analysis approach. In contrast, measures from western North American populations ranged from 0 to 0.032. These findings suggest that seasonal migratory behavior is also associated with natal and breeding dispersal tendencies. We likewise detected significantly lower genetic diversity within nonmigratory populations, reflecting the greater influence of genetic drift in small populations. We identified the signal of population expansion among nonmigratory populations, consistent with the recent establishment of higher latitude breeding locations following Pleistocene glacial retreat. Differentiation of F. s. paulus and F. s. sparverius reflected subtle differences in allele frequencies. Because migratory behavior can evolve quickly, our analyses suggest recent origins of migratory American Kestrel populations in North America.

  16. Lateral variations in mylonite zone thickness as influenced by fluid-rock interactions, Linville falls fault, North Carolina

    NASA Astrophysics Data System (ADS)

    Newman, J.; Mitra, G.

    1993-07-01

    Over a distance of approximately 20 km, along strike, the Linville Falls mylonite varies in thickness from 1 m at Linville Falls to >60 m at Banner Elk. Along strike, pressure, temperature and displacement variations are minimized, allowing this study to focus on the influences of fluid behavior and protolith mineralogy on fault zone development. The protolith at Linville Falls contains mainly K-feldspar, perthite and quartz, while at Banner Elk the protolith contains plagioclase and quartz. At Linville Falls, quartz deformed by dynamic recrystallization, feldspar by intragranular fracturing and alteration to quartz and mica, and mica by sliding along cleavage planes. Modal mineralogies change from the protolith to the mylonite with quartz decreasing from 39 to 19% and feldspar from 59 to 1.5%; muscovite increases from <1 to 80%. Mean grain size of the quartz and feldspar also decreased, from 30 to 20 μm and from 110 to 50 μm, respectively. At Banner Elk, deformation occurred predominantly by dynamic recrystallization within the quartz and by sliding along cleavage planes in mica; no feldspar remains within the mylonite zone. Modal mineralogies change from the protolith to the mylonite with quartz and muscovite increasing from 21 to 50% and from < 1 to 44%, respectively. Mean grain size of quartz decreases from 60 to 24 μm. Mass-balance calculations, based on major- and trace-element geochemistry, indicate approximately 75% volume loss at Linville Falls and 20% at Banner Elk. Fluid-rock ratios estimated from the calculated depletions of Si are an order of magnitude higher at Linville Falls than at Banner Elk. Fluids infiltrated the fault zone over a thicker zone at Banner Elk than at Linville Falls because the plagioclase altered more readily than K-feldspar, creating new pathways for fluids. Fluids migrated preferentially through channels along the fault zone, creating a three-dimensional network of higher fluid flow.

  17. Variation in migratory behavior influences regional genetic diversity and structure among American kestrel populations (Falco sparverius) in North America

    USGS Publications Warehouse

    Miller, Mark P.; Mullins, Thomas D.; Parrish, John G.; Walters, Jeffrey R.; Haig, Susan M.

    2012-01-01

    Birds employ numerous strategies to cope with seasonal fluctuations in high-quality habitat availability. Long distance migration is a common tactic; however, partial migration is especially common among broadly distributed species. Under partial migration systems, a portion of a species migrates, whereas the remainder inhabits breeding grounds year round. In this study, we identified effects of migratory behavior variation on genetic structure and diversity of American Kestrels (Falco sparverius), a widespread partial migrant in North America. American Kestrels generally migrate; however, a resident group inhabits the southeastern United States year round. The southeastern group is designated as a separate subspecies (F. s. paulus) from the migratory group (F. s. sparverius). Using mitochondrial DNA and microsatellites from 183 and 211 individuals, respectively, we illustrate that genetic structure is stronger among nonmigratory populations, with differentiation measures ranging from 0.060 to 0.189 depending on genetic marker and analysis approach. In contrast, measures from western North American populations ranged from 0 to 0.032. These findings suggest that seasonal migratory behavior is also associated with natal and breeding dispersal tendencies. We likewise detected significantly lower genetic diversity within nonmigratory populations, reflecting the greater influence of genetic drift in small populations. We identified the signal of population expansion among nonmigratory populations, consistent with the recent establishment of higher latitude breeding locations following Pleistocene glacial retreat. Differentiation of F. s. paulus and F. s. sparverius reflected subtle differences in allele frequencies. Because migratory behavior can evolve quickly, our analyses suggest recent origins of migratory American Kestrel populations in North America.

  18. FIT3D: Fitting optical spectra

    NASA Astrophysics Data System (ADS)

    Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosales-Ortega, F. F.; Cano-Díaz, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.

    2016-09-01

    FIT3D fits optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. FIT3D is focused on the analysis of Integral Field Spectroscopy data, but is not restricted to it, and is the basis of Pipe3D, a pipeline used in the analysis of datasets like CALIFA, MaNGA, and SAMI. It can run iteratively or in an automatic way to derive the parameters of a large set of spectra.

  19. Influence of a medium-impact exercise program on health-related quality of life and cardiorespiratory fitness in females with subclinical hypothyroidism: an open-label pilot study.

    PubMed

    Garces-Arteaga, Andrea; Nieto-Garcia, Nataly; Suarez-Sanchez, Freddy; Triana-Reina, Héctor Reynaldo; Ramírez-Vélez, Robinson

    2013-01-01

    Objective. To examine the influence of a medium-impact exercise program (MIEP) on health-related quality of life (HRQoL) and cardiorespiratory fitness (VO2max) in females with subclinical hypothyroidism (sHT). Materials and Methods. We selected 17 sedentary women with sHT (mean age: 43.1 (standard deviation: 9.7) years). Participants carried out an MIEP consisting of 3 weekly sessions of 60 minutes during 12 weeks. Before and after the exercise program HRQoL was assessed by the SF-12v2 questionnaire, and VO2max was evaluated by Rockport walk test. Results. After the 12-week intervention, the participants that performed an MIEP showed improvements in HRQoL in most domains, particularly the vitality domain by 7 points, the social functioning domain by 10 points, the mental health domain by 7 points, and the mental component summary by 7 points. One of the four domains within the physical component summary (general health domain) showed significant effect of the exercise intervention: 6 points. Moreover, the participants that performed exercise showed a higher VO2max (28%; P < 0.01). Conclusion. After 12 weeks of medium-impact exercise program, there were remarkable improvements in HRQoL in most domains. Moreover, this exercise program proved to have a positive influence on cardiorespiratory fitness.