Explaining health care expenditure variation: large-sample evidence using linked survey and health administrative data.

Science.gov (United States)

Ellis, Randall P; Fiebig, Denzil G; Johar, Meliyanni; Jones, Glenn; Savage, Elizabeth

2013-09-01

Explaining individual, regional, and provider variation in health care spending is of enormous value to policymakers but is often hampered by the lack of individual level detail in universal public health systems because budgeted spending is often not attributable to specific individuals. Even rarer is self-reported survey information that helps explain this variation in large samples. In this paper, we link a cross-sectional survey of 267 188 Australians age 45 and over to a panel dataset of annual healthcare costs calculated from several years of hospital, medical and pharmaceutical records. We use this data to distinguish between cost variations due to health shocks and those that are intrinsic (fixed) to an individual over three years. We find that high fixed expenditures are positively associated with age, especially older males, poor health, obesity, smoking, cancer, stroke and heart conditions. Being foreign born, speaking a foreign language at home and low income are more strongly associated with higher time-varying expenditures, suggesting greater exposure to adverse health shocks. Copyright © 2013 John Wiley & Sons, Ltd.

Variations in 137Cs activity concentrations in individual fruitbodies in clusters of Cantharellus tubaeformis

International Nuclear Information System (INIS)

Nikolova, I.; Johanson, K.J.

1999-01-01

Fruitbodies of Cantharellus tubaeformis grown in clusters were collected from a normal Swedish coniferous forest. In the laboratory, individual fruitbodies were transferred into plastic vials and the 137 Cs activity concentrations were determined and expressed as Bq kg -1 fresh weight. After drying at 55 o , the 137 CS levels were recalculated and expressed as Bq kg -1 dry weight. Large variations of 137 Cs activity concentrations between individual fruitbodies within the clusters were observed. In 1995, the range in the 137 CS levels of individual fruitbodies in one cluster were from 9,194 to 164,811 and in another cluster from 2,338 to 38,377 Bq kg -1 . The mean values for these two clusters were 90,294 and 13,556 Bq kg -1 respectively. In 1998, the mean value for eight clusters showed a range from 26,373 to 67,281 Bq kg -1 . The largest variations between individual fruitbodies within a cluster were from 11,875 to 107,160 Bq kg -1 . Refs. 10 (author)

Quantifying individual variation in the propensity to attribute incentive salience to reward cues.

Science.gov (United States)

Meyer, Paul J; Lovic, Vedran; Saunders, Benjamin T; Yager, Lindsay M; Flagel, Shelly B; Morrow, Jonathan D; Robinson, Terry E

2012-01-01

If reward-associated cues acquire the properties of incentive stimuli they can come to powerfully control behavior, and potentially promote maladaptive behavior. Pavlovian incentive stimuli are defined as stimuli that have three fundamental properties: they are attractive, they are themselves desired, and they can spur instrumental actions. We have found, however, that there is considerable individual variation in the extent to which animals attribute Pavlovian incentive motivational properties ("incentive salience") to reward cues. The purpose of this paper was to develop criteria for identifying and classifying individuals based on their propensity to attribute incentive salience to reward cues. To do this, we conducted a meta-analysis of a large sample of rats (N = 1,878) subjected to a classic Pavlovian conditioning procedure. We then used the propensity of animals to approach a cue predictive of reward (one index of the extent to which the cue was attributed with incentive salience), to characterize two behavioral phenotypes in this population: animals that approached the cue ("sign-trackers") vs. others that approached the location of reward delivery ("goal-trackers"). This variation in Pavlovian approach behavior predicted other behavioral indices of the propensity to attribute incentive salience to reward cues. Thus, the procedures reported here should be useful for making comparisons across studies and for assessing individual variation in incentive salience attribution in small samples of the population, or even for classifying single animals.

Individual variation in cone photoreceptor density in house sparrows: implications for between-individual differences in visual resolution and chromatic contrast.

Science.gov (United States)

Ensminger, Amanda L; Fernández-Juricic, Esteban

2014-01-01

Between-individual variation has been documented in a wide variety of taxa, especially for behavioral characteristics; however, intra-population variation in sensory systems has not received similar attention in wild animals. We measured a key trait of the visual system, the density of retinal cone photoreceptors, in a wild population of house sparrows (Passer domesticus). We tested whether individuals differed from each other in cone densities given within-individual variation across the retina and across eyes. We further tested whether the existing variation could lead to individual differences in two aspects of perception: visual resolution and chromatic contrast. We found consistent between-individual variation in the densities of all five types of avian cones, involved in chromatic and achromatic vision. Using perceptual modeling, we found that this degree of variation translated into significant between-individual differences in visual resolution and the chromatic contrast of a plumage signal that has been associated with mate choice and agonistic interactions. However, there was no evidence for a relationship between individual visual resolution and chromatic contrast. The implication is that some birds may have the sensory potential to perform "better" in certain visual tasks, but not necessarily in both resolution and contrast simultaneously. Overall, our findings (a) highlight the need to consider multiple individuals when characterizing sensory traits of a species, and (b) provide some mechanistic basis for between-individual variation in different behaviors (i.e., animal personalities) and for testing the predictions of several widely accepted hypotheses (e.g., honest signaling).

Partial diel migration: A facultative migration underpinned by long-term inter-individual variation.

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Harrison, Philip M; Gutowsky, Lee F G; Martins, Eduardo G; Patterson, David A; Cooke, Steven J; Power, Michael

2017-09-01

The variations in migration that comprise partial diel migrations, putatively occur entirely as a consequence of behavioural flexibility. However, seasonal partial migrations are increasingly recognised to be mediated by a combination of reversible plasticity in response to environmental variation and individual variation due to genetic and environmental effects. Here, we test the hypothesis that while partial diel migration heterogeneity occurs primarily due to short-term within-individual flexibility in behaviour, long-term individual differences in migratory behaviour also underpin this migration variation. Specifically, we use a hierarchical behavioural reaction norm approach to partition within- and among-individual variation in depth use and diel plasticity in depth use, across short- and long-term time-scales, in a group of 47 burbot (Lota lota) tagged with depth-sensing acoustic telemetry transmitters. We found that within-individual variation at the among-dates-within-seasons and among-seasons scale, explained the dominant proportion of phenotypic variation. However, individuals also repeatedly differed in their expression of migration behaviour over the 2 year study duration. These results reveal that diel migration variation occurs primarily due to short-term within-individual flexibility in depth use and diel migration behaviour. However, repeatable individual differences also played a key role in mediating partial diel migration. These findings represent a significant advancement of our understanding of the mechanisms generating the important, yet poorly understood phenomena of partial diel migration. Moreover, given the pervasive occurrence of diel migrations across aquatic taxa, these findings indicate that individual differences have an important, yet previously unacknowledged role in structuring the temporal and vertical dynamics of aquatic ecosystems. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

The causes of variation in learning and behavior: Why individual differences matter

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Bruno eSauce

2013-07-01

Full Text Available In a seminal paper written five decades ago, Cronbach discussed the two highly distinct approaches to scientific psychology: experimental and correlational. Today, although these two approaches are fruitfully implemented and embraced across some fields of psychology, this synergy is largely absent from other areas, such as in the study of learning and behavior. Both Tolman and Hull, in a rare case of agreement, stated that the correlational approach held little promise for the understanding of behavior. Interestingly, this dismissal of the study of individual differences was absent in the biologically-oriented branches of behavior analysis, namely, behavioral genetics and ethology. Here we propose that the distinction between causation and causes of variation (with its origins in the field of genetics reveal the potential value of the correlational approach in understanding the full complexity of learning and behavior. Although the experimental approach can illuminate the causal variables that modulate learning, the analysis of individual differences can elucidate how much and in which way variables interact to support variations in learning in complex natural environments. For example, understanding that a past experience with a stimulus influences its associability provides little insight into how individual predispositions interact to modulate this influence on associability. In this new light, we discuss examples from studies of individual differences in animals’ performance in the Morris Water Maze and from our own work on individual differences in general intelligence in mice. These studies illustrate that, opposed to what Underwood famously suggested, studies of individual differences can do much more to psychology than merely providing preliminary indications of cause-effect relationships.

Quantifying individual variation in the propensity to attribute incentive salience to reward cues.

Directory of Open Access Journals (Sweden)

Paul J Meyer

Full Text Available If reward-associated cues acquire the properties of incentive stimuli they can come to powerfully control behavior, and potentially promote maladaptive behavior. Pavlovian incentive stimuli are defined as stimuli that have three fundamental properties: they are attractive, they are themselves desired, and they can spur instrumental actions. We have found, however, that there is considerable individual variation in the extent to which animals attribute Pavlovian incentive motivational properties ("incentive salience" to reward cues. The purpose of this paper was to develop criteria for identifying and classifying individuals based on their propensity to attribute incentive salience to reward cues. To do this, we conducted a meta-analysis of a large sample of rats (N = 1,878 subjected to a classic Pavlovian conditioning procedure. We then used the propensity of animals to approach a cue predictive of reward (one index of the extent to which the cue was attributed with incentive salience, to characterize two behavioral phenotypes in this population: animals that approached the cue ("sign-trackers" vs. others that approached the location of reward delivery ("goal-trackers". This variation in Pavlovian approach behavior predicted other behavioral indices of the propensity to attribute incentive salience to reward cues. Thus, the procedures reported here should be useful for making comparisons across studies and for assessing individual variation in incentive salience attribution in small samples of the population, or even for classifying single animals.

Reducing Individual Variation for fMRI Studies in Children by Minimizing Template Related Errors.

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Jian Weng

Full Text Available Spatial normalization is an essential process for group comparisons in functional MRI studies. In practice, there is a risk of normalization errors particularly in studies involving children, seniors or diseased populations and in regions with high individual variation. One way to minimize normalization errors is to create a study-specific template based on a large sample size. However, studies with a large sample size are not always feasible, particularly for children studies. The performance of templates with a small sample size has not been evaluated in fMRI studies in children. In the current study, this issue was encountered in a working memory task with 29 children in two groups. We compared the performance of different templates: a study-specific template created by the experimental population, a Chinese children template and the widely used adult MNI template. We observed distinct differences in the right orbitofrontal region among the three templates in between-group comparisons. The study-specific template and the Chinese children template were more sensitive for the detection of between-group differences in the orbitofrontal cortex than the MNI template. Proper templates could effectively reduce individual variation. Further analysis revealed a correlation between the BOLD contrast size and the norm index of the affine transformation matrix, i.e., the SFN, which characterizes the difference between a template and a native image and differs significantly across subjects. Thereby, we proposed and tested another method to reduce individual variation that included the SFN as a covariate in group-wise statistics. This correction exhibits outstanding performance in enhancing detection power in group-level tests. A training effect of abacus-based mental calculation was also demonstrated, with significantly elevated activation in the right orbitofrontal region that correlated with behavioral response time across subjects in the trained group.

Individual Variation in Hunger, Energy Intake, and Ghrelin Responses to Acute Exercise.

Science.gov (United States)

King, James A; Deighton, Kevin; Broom, David R; Wasse, Lucy K; Douglas, Jessica A; Burns, Stephen F; Cordery, Philip A; Petherick, Emily S; Batterham, Rachel L; Goltz, Fernanda R; Thackray, Alice E; Yates, Thomas; Stensel, David J

2017-06-01

This study aimed to characterize the immediate and extended effect of acute exercise on hunger, energy intake, and circulating acylated ghrelin concentrations using a large data set of homogenous experimental trials and to describe the variation in responses between individuals. Data from 17 of our group's experimental crossover trials were aggregated yielding a total sample of 192 young, healthy males. In these studies, single bouts of moderate to high-intensity aerobic exercise (69% ± 5% V˙O2 peak; mean ± SD) were completed with detailed participant assessments occurring during and for several hours postexercise. Mean hunger ratings were determined during (n = 178) and after (n = 118) exercise from visual analog scales completed at 30-min intervals, whereas ad libitum energy intake was measured within the first hour after exercise (n = 60) and at multiple meals (n = 128) during the remainder of trials. Venous concentrations of acylated ghrelin were determined at strategic time points during (n = 118) and after (n = 89) exercise. At group level, exercise transiently suppressed hunger (P hunger and circulating acylated ghrelin concentrations with notable diversity between individuals. Care must be taken to distinguish true interindividual variation from random differences within normal limits.

King eiders use an income strategy for egg production: a case study for incorporating individual dietary variation into nutrient allocation research.

Science.gov (United States)

Oppel, Steffen; Powell, Abby N; O'Brien, Diane M

2010-09-01

The use of stored nutrients for reproduction represents an important component of life-history variation. Recent studies from several species have used stable isotopes to estimate the reliance on stored body reserves in reproduction. Such approaches rely on population-level dietary endpoints to characterize stored reserves ("capital") and current diet ("income"). Individual variation in diet choice has so far not been incorporated in such approaches, but is crucial for assessing variation in nutrient allocation strategies. We investigated nutrient allocation to egg production in a large-bodied sea duck in northern Alaska, the king eider (Somateria spectabilis). We first used Bayesian isotopic mixing models to quantify at the population level the amount of endogenous carbon and nitrogen invested into egg proteins based on carbon and nitrogen isotope ratios. We then defined the isotopic signature of the current diet of every nesting female based on isotope ratios of eggshell membranes, because diets varied isotopically among individual king eiders on breeding grounds. We used these individual-based dietary isotope signals to characterize nutrient allocation for each female in the study population. At the population level, the Bayesian and the individual-based approaches yielded identical results, and showed that king eiders used an income strategy for the synthesis of egg proteins. The majority of the carbon and nitrogen in albumen (C: 86 +/- 18%, N: 99 +/- 1%) and the nitrogen in lipid-free yolk (90 +/- 15%) were derived from food consumed on breeding grounds. Carbon in lipid-free yolk derived evenly from endogenous sources and current diet (exogenous C: 54 +/- 24%), but source contribution was highly variable among individual females. These results suggest that even large-bodied birds traditionally viewed as capital breeders use exogenous nutrients for reproduction. We recommend that investigations of nutrient allocation should incorporate individual variation into

Observer variation in grading sacroiliac radiographs in HLA-B27 positive individuals

International Nuclear Information System (INIS)

Hollingsworth, P.N.; Cheah, P.S.; Dawkins, R.L.; Owen, E.T.; Calin, A.; Wood, P.H.N.

1983-01-01

This study attempts to reconcile the apparent differences in the reported frequency of ankylosing spondylitis and radiological sacroilitis in HLA-B27 positive individuals. Pelvic radiographs from 125 Busselton subjects were mixed with 81 other films selected to illustrate the possible range of sacroiliac changes and were graded by observers who were involved in 2 of the conflicting studies and by a 3rd independent observer. Concordance was high for advanced bilateral disease but not for unilateral and milder changes. Variation between observers and the interpretation of sacroiliac radiographs is sufficiently large to account for much of the disagreement between frequency estimates

Brief report: large individual variation in outcomes of autistic children receiving low-intensity behavioral interventions in community settings.

Science.gov (United States)

Kamio, Yoko; Haraguchi, Hideyuki; Miyake, Atsuko; Hiraiwa, Mikio

2015-01-01

Despite widespread awareness of the necessity of early intervention for children with autism spectrum disorders (ASDs), evidence is still limited, in part, due to the complex nature of ASDs. This exploratory study aimed to examine the change across time in young children with autism and their mothers, who received less intensive early interventions with and without applied behavior analysis (ABA) methods in community settings in Japan. Eighteen children with autism (mean age: 45.7 months; range: 28-64 months) received ABA-based treatment (a median of 3.5 hours per week; an interquartile range of 2-5.6 hours per week) and/or eclectic treatment-as-usual (TAU) (a median of 3.1 hours per week; an interquartile range of 2-5.6 hours per week). Children's outcomes were the severity of autistic symptoms, cognitive functioning, internalizing and externalizing behavior after 6 months (a median of 192 days; an interquartile range of 178-206 days). In addition, maternal parenting stress at 6-month follow-up, and maternal depression at 1.5-year follow-up (a median of 512 days; an interquartile range of 358-545 days) were also examined. Large individual variations were observed for a broad range of children's and mothers' outcomes. Neither ABA nor TAU hours per week were significantly associated with an improvement in core autistic symptoms. A significant improvement was observed only for internalizing problems, irrespective of the type, intensity or monthly cost of treatment received. Higher ABA cost per month (a median of 1,188 USD; an interquartile range of 538-1,888 USD) was associated with less improvement in language-social DQ (a median of 9; an interquartile range of -6.75-23.75). To determine an optimal program for each child with ASD in areas with poor ASD resources, further controlled studies are needed that assess a broad range of predictive and outcome variables focusing on both individual characteristics and treatment components.

Utilising identifier error variation in linkage of large administrative data sources

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Katie Harron

2017-02-01

Full Text Available Abstract Background Linkage of administrative data sources often relies on probabilistic methods using a set of common identifiers (e.g. sex, date of birth, postcode. Variation in data quality on an individual or organisational level (e.g. by hospital can result in clustering of identifier errors, violating the assumption of independence between identifiers required for traditional probabilistic match weight estimation. This potentially introduces selection bias to the resulting linked dataset. We aimed to measure variation in identifier error rates in a large English administrative data source (Hospital Episode Statistics; HES and to incorporate this information into match weight calculation. Methods We used 30,000 randomly selected HES hospital admissions records of patients aged 0–1, 5–6 and 18–19 years, for 2011/2012, linked via NHS number with data from the Personal Demographic Service (PDS; our gold-standard. We calculated identifier error rates for sex, date of birth and postcode and used multi-level logistic regression to investigate associations with individual-level attributes (age, ethnicity, and gender and organisational variation. We then derived: i weights incorporating dependence between identifiers; ii attribute-specific weights (varying by age, ethnicity and gender; and iii organisation-specific weights (by hospital. Results were compared with traditional match weights using a simulation study. Results Identifier errors (where values disagreed in linked HES-PDS records or missing values were found in 0.11% of records for sex and date of birth and in 53% of records for postcode. Identifier error rates differed significantly by age, ethnicity and sex (p < 0.0005. Errors were less frequent in males, in 5–6 year olds and 18–19 year olds compared with infants, and were lowest for the Asian ethic group. A simulation study demonstrated that substantial bias was introduced into estimated readmission rates in the presence

Personality matters: individual variation in reactions of naive bird predators to aposematic prey

NARCIS (Netherlands)

Exnerová, A.; Hotova Svadova, K.; Fucikova, E.; Drent, P.; Stys, P.

2010-01-01

Variation in reactions to aposematic prey is common among conspecific individuals of bird predators. It may result from different individual experience but it also exists among naive birds. This variation may possibly be explained by the effect of personality—a complex of correlated, heritable

King eider use an income strategy for egg production: a case study for incorporating individual dietary variation into nutrient allocation research

Science.gov (United States)

Oppel, Steffen; Powell, Abby N.; O'Brien, Diane M.

2010-01-01

The use of stored nutrients for reproduction represents an important component of life-history variation. Recent studies from several species have used stable isotopes to estimate the reliance on stored body reserves in reproduction. Such approaches rely on population-level dietary endpoints to characterize stored reserves (“capital”) and current diet (“income”). Individual variation in diet choice has so far not been incorporated in such approaches, but is crucial for assessing variation in nutrient allocation strategies. We investigated nutrient allocation to egg production in a large-bodied sea duck in northern Alaska, the king eider (Somateria spectabilis). We first used Bayesian isotopic mixing models to quantify at the population level the amount of endogenous carbon and nitrogen invested into egg proteins based on carbon and nitrogen isotope ratios. We then defined the isotopic signature of the current diet of every nesting female based on isotope ratios of eggshell membranes, because diets varied isotopically among individual king eiders on breeding grounds. We used these individual-based dietary isotope signals to characterize nutrient allocation for each female in the study population. At the population level, the Bayesian and the individual-based approaches yielded identical results, and showed that king eiders used an income strategy for the synthesis of egg proteins. The majority of the carbon and nitrogen in albumen (C: 86 ± 18%, N: 99 ± 1%) and the nitrogen in lipid-free yolk (90 ± 15%) were derived from food consumed on breeding grounds. Carbon in lipid-free yolk derived evenly from endogenous sources and current diet (exogenous C: 54 ± 24%), but source contribution was highly variable among individual females. These results suggest that even large-bodied birds traditionally viewed as capital breeders use exogenous nutrients for reproduction. We recommend that investigations of nutrient allocation should incorporate individual

Characterization and potential functional significance of human-chimpanzee large INDEL variation

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Polavarapu Nalini

2011-10-01

Full Text Available Abstract Background Although humans and chimpanzees have accumulated significant differences in a number of phenotypic traits since diverging from a common ancestor about six million years ago, their genomes are more than 98.5% identical at protein-coding loci. This modest degree of nucleotide divergence is not sufficient to explain the extensive phenotypic differences between the two species. It has been hypothesized that the genetic basis of the phenotypic differences lies at the level of gene regulation and is associated with the extensive insertion and deletion (INDEL variation between the two species. To test the hypothesis that large INDELs (80 to 12,000 bp may have contributed significantly to differences in gene regulation between the two species, we categorized human-chimpanzee INDEL variation mapping in or around genes and determined whether this variation is significantly correlated with previously determined differences in gene expression. Results Extensive, large INDEL variation exists between the human and chimpanzee genomes. This variation is primarily attributable to retrotransposon insertions within the human lineage. There is a significant correlation between differences in gene expression and large human-chimpanzee INDEL variation mapping in genes or in proximity to them. Conclusions The results presented herein are consistent with the hypothesis that large INDELs, particularly those associated with retrotransposons, have played a significant role in human-chimpanzee regulatory evolution.

High responders and low responders: factors associated with individual variation in response to standardized training.

Science.gov (United States)

Mann, Theresa N; Lamberts, Robert P; Lambert, Michael I

2014-08-01

The response to an exercise intervention is often described in general terms, with the assumption that the group average represents a typical response for most individuals. In reality, however, it is more common for individuals to show a wide range of responses to an intervention rather than a similar response. This phenomenon of 'high responders' and 'low responders' following a standardized training intervention may provide helpful insights into mechanisms of training adaptation and methods of training prescription. Therefore, the aim of this review was to discuss factors associated with inter-individual variation in response to standardized, endurance-type training. It is well-known that genetic influences make an important contribution to individual variation in certain training responses. The association between genotype and training response has often been supported using heritability estimates; however, recent studies have been able to link variation in some training responses to specific single nucleotide polymorphisms. It would appear that hereditary influences are often expressed through hereditary influences on the pre-training phenotype, with some parameters showing a hereditary influence in the pre-training phenotype but not in the subsequent training response. In most cases, the pre-training phenotype appears to predict only a small amount of variation in the subsequent training response of that phenotype. However, the relationship between pre-training autonomic activity and subsequent maximal oxygen uptake response appears to show relatively stronger predictive potential. Individual variation in response to standardized training that cannot be explained by genetic influences may be related to the characteristics of the training program or lifestyle factors. Although standardized programs usually involve training prescribed by relative intensity and duration, some methods of relative exercise intensity prescription may be more successful in creating

Estimating variation in stomatal frequency at intra-individual, intra-site, and inter-taxonomic levels in populations of the Leonardoxa africana (Fabaceae) complex over environmental gradients in Cameroon

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Finsinger, Walter; Dos Santos, Thibaut; McKey, Doyle

2013-07-01

Variation of stomatal frequency (stomatal density and stomatal index) includes genetically-based, potentially-adaptive variation, and variation due to phenotypic plasticity, the degree of which may be fundamental to the ability to maintain high water-use efficiency and thus to deal with environmental change. We analysed stomatal frequency and morphology (pore length, pore width) in leaves from several individuals from nine populations of four sub-species of the Leonardoxa africana complex. The dataset represents a hierarchical sampling wherein factors are nested within each level (leaves in individuals, individuals in sites, etc.), allowing estimation of the contribution of different levels to overall variation, using variance-component analysis. SI showed significant variation among sites ("site" is largely confounded with "sub-species"), being highest in the sub-species localized in the highest-elevation site. However, most of the observed variance was accounted for at intra-site and intra-individual levels. This variance could reflect great phenotypic plasticity, presumably in response to highly local variation in micro-environmental conditions.

Tree phyllosphere bacterial communities: exploring the magnitude of intra- and inter-individual variation among host species

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Isabelle Laforest-Lapointe

2016-08-01

Full Text Available Background The diversity and composition of the microbial community of tree leaves (the phyllosphere varies among trees and host species and along spatial, temporal, and environmental gradients. Phyllosphere community variation within the canopy of an individual tree exists but the importance of this variation relative to among-tree and among-species variation is poorly understood. Sampling techniques employed for phyllosphere studies include picking leaves from one canopy location to mixing randomly selected leaves from throughout the canopy. In this context, our goal was to characterize the relative importance of intra-individual variation in phyllosphere communities across multiple species, and compare this variation to inter-individual and interspecific variation of phyllosphere epiphytic bacterial communities in a natural temperate forest in Quebec, Canada. Methods We targeted five dominant temperate forest tree species including angiosperms and gymnosperms: Acer saccharum, Acer rubrum, Betula papyrifera, Abies balsamea and Picea glauca. For one randomly selected tree of each species, we sampled microbial communities at six distinct canopy locations: bottom-canopy (1–2 m height, the four cardinal points of mid-canopy (2–4 m height, and the top-canopy (4–6 m height. We also collected bottom-canopy leaves from five additional trees from each species. Results Based on an analysis of bacterial community structure measured via Illumina sequencing of the bacterial 16S gene, we demonstrate that 65% of the intra-individual variation in leaf bacterial community structure could be attributed to the effect of inter-individual and inter-specific differences while the effect of canopy location was not significant. In comparison, host species identity explains 47% of inter-individual and inter-specific variation in leaf bacterial community structure followed by individual identity (32% and canopy location (6%. Discussion Our results suggest that

Seasonal variation of dystocia in a large Danish cohort.

Science.gov (United States)

Rohr Thomsen, Christine; Uldbjerg, Niels; Hvidman, Lone; Atladóttir, Hjördís Ósk; Henriksen, Tine Brink; Milidou, Ioanna

2014-01-01

Dystocia is one of the most frequent causes of cesarean delivery in nulliparous women. Despite this, its causes are largely unknown. Vitamin D receptor (VDR) has been found in the myometrium. Thus, it is possible that vitamin D affects the contractility of the myometrium and may be involved in the pathogenesis of dystocia. Seasonal variation of dystocia in areas with distinct seasonal variation in sunlight exposure, like Denmark, could imply that vitamin D may play a role. This study examined whether there was seasonal variation in the incidence of dystocia in a Danish population. We used information from a cohort of 34,261 nulliparous women with singleton pregnancies, spontaneous onset of labor between 37 and 42 completed gestational weeks, and vertex fetal presentation. All women gave birth between 1992 and 2010 at the Department of Obstetrics and Gynecology, Aarhus University Hospital, Skejby. Logistic regression combined with cubic spline was used to estimate the seasonal variation for each outcome after adjusting for calendar time. No evidence for seasonal variation was found for any of the outcomes: acute cesarean delivery due to dystocia (p = 0.44); instrumental vaginal delivery due to dystocia (p = 0.69); oxytocin augmentation due to dystocia (p = 0.46); and overall dystocia (p = 0.91). No seasonal variation in the incidence of dystocia was observed in a large cohort of Danish women. This may reflect no association between vitamin D and dystocia, or alternatively that other factors with seasonal variation and influence on the occurrence of dystocia attenuate such an association.

Who Punishes? Personality Traits Predict Individual Variation in Punitive Sentiment

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S. Craig Roberts

2013-01-01

Full Text Available Cross-culturally, participants in public goods games reward participants and punish defectors to a degree beyond that warranted by rational, profit-maximizing considerations. Costly punishment, where individuals impose costs on defectors at a cost to themselves, is thought to promote the maintenance of cooperation. However, despite substantial variation in the extent to which people punish, little is known about why some individuals, and not others, choose to pay these costs. Here, we test whether personality traits might contribute to variation in helping and punishment behavior. We first replicate a previous study using public goods scenarios to investigate effects of sex, relatedness and likelihood of future interaction on willingness to help a group member or to punish a transgressor. As in the previous study, we find that individuals are more willing to help related than unrelated needy others and that women are more likely to express desire to help than men. Desire to help was higher if the probability of future interaction is high, at least among women. In contrast, among these variables, only participant sex predicted some measures of punitive sentiment. Extending the replication, we found that punitive sentiment, but not willingness to help, was predicted by personality traits. Most notably, participants scoring lower on Agreeableness expressed more anger towards and greater desire to punish a transgressor, and were more willing to engage in costly punishment, at least in our scenario. Our results suggest that some personality traits may contribute to underpinning individual variation in social enforcement of cooperation.

Determining individual variation in growth and its implication for life-history and population processes using the empirical Bayes method.

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Simone Vincenzi

2014-09-01

Full Text Available The differences in demographic and life-history processes between organisms living in the same population have important consequences for ecological and evolutionary dynamics. Modern statistical and computational methods allow the investigation of individual and shared (among homogeneous groups determinants of the observed variation in growth. We use an Empirical Bayes approach to estimate individual and shared variation in somatic growth using a von Bertalanffy growth model with random effects. To illustrate the power and generality of the method, we consider two populations of marble trout Salmo marmoratus living in Slovenian streams, where individually tagged fish have been sampled for more than 15 years. We use year-of-birth cohort, population density during the first year of life, and individual random effects as potential predictors of the von Bertalanffy growth function's parameters k (rate of growth and L∞ (asymptotic size. Our results showed that size ranks were largely maintained throughout marble trout lifetime in both populations. According to the Akaike Information Criterion (AIC, the best models showed different growth patterns for year-of-birth cohorts as well as the existence of substantial individual variation in growth trajectories after accounting for the cohort effect. For both populations, models including density during the first year of life showed that growth tended to decrease with increasing population density early in life. Model validation showed that predictions of individual growth trajectories using the random-effects model were more accurate than predictions based on mean size-at-age of fish.

Determining individual variation in growth and its implication for life-history and population processes using the empirical Bayes method.

Science.gov (United States)

Vincenzi, Simone; Mangel, Marc; Crivelli, Alain J; Munch, Stephan; Skaug, Hans J

2014-09-01

The differences in demographic and life-history processes between organisms living in the same population have important consequences for ecological and evolutionary dynamics. Modern statistical and computational methods allow the investigation of individual and shared (among homogeneous groups) determinants of the observed variation in growth. We use an Empirical Bayes approach to estimate individual and shared variation in somatic growth using a von Bertalanffy growth model with random effects. To illustrate the power and generality of the method, we consider two populations of marble trout Salmo marmoratus living in Slovenian streams, where individually tagged fish have been sampled for more than 15 years. We use year-of-birth cohort, population density during the first year of life, and individual random effects as potential predictors of the von Bertalanffy growth function's parameters k (rate of growth) and L∞ (asymptotic size). Our results showed that size ranks were largely maintained throughout marble trout lifetime in both populations. According to the Akaike Information Criterion (AIC), the best models showed different growth patterns for year-of-birth cohorts as well as the existence of substantial individual variation in growth trajectories after accounting for the cohort effect. For both populations, models including density during the first year of life showed that growth tended to decrease with increasing population density early in life. Model validation showed that predictions of individual growth trajectories using the random-effects model were more accurate than predictions based on mean size-at-age of fish.

Demystifying animal 'personality' (or not): why individual variation matters to experimental biologists.

Science.gov (United States)

Roche, Dominique G; Careau, Vincent; Binning, Sandra A

2016-12-15

Animal 'personality', defined as repeatable inter-individual differences in behaviour, is a concept in biology that faces intense controversy. Critics argue that the field is riddled with terminological and methodological inconsistencies and lacks a sound theoretical framework. Nevertheless, experimental biologists are increasingly studying individual differences in physiology and relating these to differences in behaviour, which can lead to fascinating insights. We encourage this trend, and in this Commentary we highlight some of the benefits of estimating variation in (and covariation among) phenotypic traits at the inter- and intra-individual levels. We focus on behaviour while drawing parallels with physiological and performance-related traits. First, we outline some of the confusion surrounding the terminology used to describe repeatable inter-individual differences in behaviour. Second, we argue that acknowledging individual behavioural differences can help researchers avoid sampling and experimental bias, increase explanatory power and, ultimately, understand how selection acts on physiological traits. Third, we summarize the latest methods to collect, analyse and present data on individual trait variation. We note that, while measuring the repeatability of phenotypic traits is informative in its own right, it is only the first step towards understanding how natural selection and genetic architecture shape intra-specific variation in complex, labile traits. Thus, understanding how and why behavioural traits evolve requires linking repeatable inter-individual behavioural differences with core aspects of physiology (e.g. neurophysiology, endocrinology, energy metabolism) and evolutionary biology (e.g. selection gradients, heritability). © 2016. Published by The Company of Biologists Ltd.

Consistent Individual Behavioral Variation: The Difference between Temperament, Personality and Behavioral Syndromes

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Jill R. D. MacKay

2015-07-01

Full Text Available Ethologists use a variety of terminology such as “personality”, “temperament” and “behavioral syndromes” almost interchangeably to discuss the phenomenon of individuals within a population of animals consistently varying from one another in their behavioral responses to stimuli. This interchangeable usage of terminology has contributed to confusion within the field of animal behavior and limits the study of the phenomenon. Here we use a rapid, non-exhaustive and repeatable search strategy literature review to investigate where there were unique distinctions between these three terms and where there was an overlap in their usage. We identified three main areas of confusion in terminology: historical usage which is not updated; a lack of precision between different fields of study; and a lack of precision between different levels of variation. We propose a framework with which to understand and define the terms based on the levels of variation ethologists are interested in. Consistent individual animal behavioral variation relates to the different structures of variation of between-individual/between-population and between and across contexts. By formalizing this framework we provide clarity between the three terms which can be easily defined and understood.

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

Energy Technology Data Exchange (ETDEWEB)

Jager, Yetta [ORNL

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.

Individual quality explains variation in reproductive success better than territory quality in a long-lived territorial raptor.

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Jabi Zabala

Full Text Available Evolution by natural selection depends on the relationship between individual traits and fitness. Variation in individual fitness can result from habitat (territory quality and individual variation. Individual quality and specialization can have a deep impact on fitness, yet in most studies on territorial species the quality of territory and individuals are confused. We aimed to determine if variation in breeding success is better explained by territories, individual quality or a combination of both. We analysed the number of fledglings and the breeding quality index (the difference between the number of fledglings of an individual/breeding pair and the average number of fledglings of the monitored territories in the same year as part of a long term (16 years peregrine falcon (Falco peregrinus monitoring program with identification of individuals. Using individual and territory identities as correlates of quality, we built Generalised Linear Models with Mixed effects, in which random factors depicted different hypotheses for sources of variation (territory/individual quality in the reproductive success of unique breeding pairs, males and females, and assessed their performance. Most evidence supported the hypothesis that variation in breeding success is explained by individual identity, particularly male identity, rather than territory. There is also some evidence for inter year variations in the breeding success of females and a territory effect in the case of males. We argue that, in territorial species, individual quality is a major source of variation in breeding success, often masked by territory. Future ecological and conservation studies on habitat use should consider and include the effect of individuals, in order to avoid misleading results.

Camouflage and individual variation in shore crabs (Carcinus maenas from different habitats.

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Martin Stevens

Full Text Available Camouflage is widespread throughout the natural world and conceals animals from predators in a vast range of habitats. Because successful camouflage usually involves matching aspects of the background environment, species and populations should evolve appearances tuned to their local habitat, termed phenotype-environment associations. However, although this has been studied in various species, little work has objectively quantified the appearances of camouflaged animals from different habitats, or related this to factors such as ontogeny and individual variation. Here, we tested for phenotype-environment associations in the common shore crab (Carcinus maenas, a species highly variable in appearance and found in a wide range of habitats. We used field surveys and digital image analysis of the colors and patterns of crabs found in four locations around Cornwall in the UK to quantify how individuals vary with habitat (predominantly rockpool, mussel bed, and mudflat. We find that individuals from sites comprising different backgrounds show substantial differences in several aspects of color and pattern, and that this is also dependent on life stage (adult or juvenile. Furthermore, the level of individual variation is dependent on site and life stage, with juvenile crabs often more variable than adults, and individuals from more homogenous habitats less diverse. Ours is the most comprehensive study to date exploring phenotype-environment associations for camouflage and individual variation in a species, and we discuss the implications of our results in terms of the mechanisms and selection pressures that may drive this.

Camouflage and individual variation in shore crabs (Carcinus maenas) from different habitats.

Science.gov (United States)

Stevens, Martin; Lown, Alice E; Wood, Louisa E

2014-01-01

Camouflage is widespread throughout the natural world and conceals animals from predators in a vast range of habitats. Because successful camouflage usually involves matching aspects of the background environment, species and populations should evolve appearances tuned to their local habitat, termed phenotype-environment associations. However, although this has been studied in various species, little work has objectively quantified the appearances of camouflaged animals from different habitats, or related this to factors such as ontogeny and individual variation. Here, we tested for phenotype-environment associations in the common shore crab (Carcinus maenas), a species highly variable in appearance and found in a wide range of habitats. We used field surveys and digital image analysis of the colors and patterns of crabs found in four locations around Cornwall in the UK to quantify how individuals vary with habitat (predominantly rockpool, mussel bed, and mudflat). We find that individuals from sites comprising different backgrounds show substantial differences in several aspects of color and pattern, and that this is also dependent on life stage (adult or juvenile). Furthermore, the level of individual variation is dependent on site and life stage, with juvenile crabs often more variable than adults, and individuals from more homogenous habitats less diverse. Ours is the most comprehensive study to date exploring phenotype-environment associations for camouflage and individual variation in a species, and we discuss the implications of our results in terms of the mechanisms and selection pressures that may drive this.

High temperature triggers latent variation among individuals: oviposition rate and probability for outbreaks.

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Christer Björkman

2011-01-01

Full Text Available It is anticipated that extreme population events, such as extinctions and outbreaks, will become more frequent as a consequence of climate change. To evaluate the increased probability of such events, it is crucial to understand the mechanisms involved. Variation between individuals in their response to climatic factors is an important consideration, especially if microevolution is expected to change the composition of populations.Here we present data of a willow leaf beetle species, showing high variation among individuals in oviposition rate at a high temperature (20 °C. It is particularly noteworthy that not all individuals responded to changes in temperature; individuals laying few eggs at 20 °C continued to do so when transferred to 12 °C, whereas individuals that laid many eggs at 20 °C reduced their oviposition and laid the same number of eggs as the others when transferred to 12 °C. When transferred back to 20 °C most individuals reverted to their original oviposition rate. Thus, high variation among individuals was only observed at the higher temperature. Using a simple population model and based on regional climate change scenarios we show that the probability of outbreaks increases if there is a realistic increase in the number of warm summers. The probability of outbreaks also increased with increasing heritability of the ability to respond to increased temperature.If climate becomes warmer and there is latent variation among individuals in their temperature response, the probability for outbreaks may increase. However, the likelihood for microevolution to play a role may be low. This conclusion is based on the fact that it has been difficult to show that microevolution affect the probability for extinctions. Our results highlight the urge for cautiousness when predicting the future concerning probabilities for extreme population events.

Rare copy number deletions predict individual variation in intelligence.

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Ronald A Yeo

2011-01-01

Full Text Available Phenotypic variation in human intellectual functioning shows substantial heritability, as demonstrated by a long history of behavior genetic studies. Many recent molecular genetic studies have attempted to uncover specific genetic variations responsible for this heritability, but identified effects capture little variance and have proven difficult to replicate. The present study, motivated an interest in "mutation load" emerging from evolutionary perspectives, examined the importance of the number of rare (or infrequent copy number variations (CNVs, and the total number of base pairs included in such deletions, for psychometric intelligence. Genetic data was collected using the Illumina 1MDuoBeadChip Array from a sample of 202 adult individuals with alcohol dependence, and a subset of these (N = 77 had been administered the Wechsler Abbreviated Scale of Intelligence (WASI. After removing CNV outliers, the impact of rare genetic deletions on psychometric intelligence was investigated in 74 individuals. The total length of the rare deletions significantly and negatively predicted intelligence (r = -.30, p = .01. As prior studies have indicated greater heritability in individuals with relatively higher parental socioeconomic status (SES, we also examined the impact of ethnicity (Anglo/White vs. Other, as a proxy measure of SES; these groups did not differ on any genetic variable. This categorical variable significantly moderated the effect of length of deletions on intelligence, with larger effects being noted in the Anglo/White group. Overall, these results suggest that rare deletions (between 5% and 1% population frequency or less adversely affect intellectual functioning, and that pleotropic effects might partly account for the association of intelligence with health and mental health status. Significant limitations of this research, including issues of generalizability and CNV measurement, are discussed.

Rare Copy Number Deletions Predict Individual Variation in Intelligence

Science.gov (United States)

Yeo, Ronald A.; Gangestad, Steven W.; Liu, Jingyu; Calhoun, Vince D.; Hutchison, Kent E.

2011-01-01

Phenotypic variation in human intellectual functioning shows substantial heritability, as demonstrated by a long history of behavior genetic studies. Many recent molecular genetic studies have attempted to uncover specific genetic variations responsible for this heritability, but identified effects capture little variance and have proven difficult to replicate. The present study, motivated an interest in “mutation load” emerging from evolutionary perspectives, examined the importance of the number of rare (or infrequent) copy number variations (CNVs), and the total number of base pairs included in such deletions, for psychometric intelligence. Genetic data was collected using the Illumina 1MDuoBeadChip Array from a sample of 202 adult individuals with alcohol dependence, and a subset of these (N = 77) had been administered the Wechsler Abbreviated Scale of Intelligence (WASI). After removing CNV outliers, the impact of rare genetic deletions on psychometric intelligence was investigated in 74 individuals. The total length of the rare deletions significantly and negatively predicted intelligence (r = −.30, p = .01). As prior studies have indicated greater heritability in individuals with relatively higher parental socioeconomic status (SES), we also examined the impact of ethnicity (Anglo/White vs. Other), as a proxy measure of SES; these groups did not differ on any genetic variable. This categorical variable significantly moderated the effect of length of deletions on intelligence, with larger effects being noted in the Anglo/White group. Overall, these results suggest that rare deletions (between 5% and 1% population frequency or less) adversely affect intellectual functioning, and that pleotropic effects might partly account for the association of intelligence with health and mental health status. Significant limitations of this research, including issues of generalizability and CNV measurement, are discussed. PMID:21298096

Individual variation in ontogenetic niche shifts in habitat use and movement patterns of a large estuarine predator (Carcharhinus leucas).

Science.gov (United States)

Matich, Philip; Heithaus, Michael R

2015-06-01

Ontogenetic niche shifts are common among animals, yet most studies only investigate niche shifts at the population level, which may overlook considerable differences among individuals in the timing and dynamics of these shifts. Such divergent behaviors within size-/age-classes have important implications for the roles a population-and specific age-classes-play in their respective ecosystem(s). Using acoustic telemetry, we tracked the movements of juvenile bull sharks in the Shark River Estuary of Everglades National Park, Florida, and found that sharks increased their use of marine microhabitats with age to take advantage of more abundant resources, but continued to use freshwater and estuarine microhabitats as refuges from marine predators. Within this population-level ontogenetic niche shift, however, movement patterns varied among individual sharks, with 47 % of sharks exhibiting condition-dependent habitat use and 53 % appearing risk-averse regardless of body condition. Among sharks older than age 0, fifty percent made regular movements between adjacent regions of the estuary, while the other half made less predictable movements that often featured long-term residence in specific regions. Individual differences were apparently shaped by both intrinsic and extrinsic factors, including individual responses to food-risk trade-offs and body condition. These differences appear to develop early in the lives of bull sharks, and persist throughout their residencies in nursery habitats. The widespread occurrence of intraspecific variation in behavior among mobile taxa suggests it is important in shaping population dynamics of at least some species, and elucidating the contexts and timing in which it develops and persists is important for understanding its role within communities.

Individual variation in children's reading comprehension across digital text types

NARCIS (Netherlands)

Fesel, S.S.; Segers, P.C.J.; Verhoeven, L.T.W.

2018-01-01

The present study examined children's digital text comprehension of digital text types linear digital text vs hypertext, with or without graphical navigable overviews. We investigated to what extent individual variation in children's comprehension could be explained by lexical quality (word reading

Individualism, collectivism, and Chinese adolescents' aggression: intracultural variations.

Science.gov (United States)

Li, Yan; Wang, Mo; Wang, Cixin; Shi, Junqi

2010-01-01

This study examined the relations between cultural values (i.e., individualism and collectivism) and aggression among 460 (234 girls) Chinese adolescents. Conflict level and social status insecurity were examined as potential explaining mechanisms for these relations. The results showed that adolescents' endorsement of collectivism was negatively related to their use of overt and relational aggression as reported by teachers and peers, whereas positive associations were found between the endorsement of individualism and adolescent aggression. Adolescents' conflict level and social status insecurity accounted for a significant part of these associations. Findings of this study demonstrate the importance of examining intracultural variations of cultural values in relation to adolescent aggression as well as the process variables in explaining the relations. (c) 2010 Wiley-Liss, Inc.

Transcriptome analysis of the sea cucumber (Apostichopus japonicus) with variation in individual growth.

Science.gov (United States)

Gao, Lei; He, Chongbo; Bao, Xiangbo; Tian, Meilin; Ma, Zhen

2017-01-01

The sea cucumber (Apostichopus japonicus) is an economically important aquaculture species in China. However, the serious individual growth variation often caused financial losses to farmers and the genetic mechanisms are poorly understood. In the present study, the extensively analysis at the transcriptome level for individual growth variation in sea cucumber was carried out. A total of 118946 unigenes were assembled from 255861 transcripts, with N50 of 1700. Of all unigenes, about 23% were identified with at least one significant match to known databases. In all four pair of comparison, 1840 genes were found to be expressed differently. Global hypometabolism was found to be occurred in the slow growing population, based on which the hypothesis was raised that growth retardation in individual growth variation of sea cucumber is one type of dormancy which is used to be against to adverse circumstances. Besides, the pathways such as ECM-receptor interaction and focal adhesion were enriched in the maintenance of cell and tissue structure and communication. Further, 76645 SSRs, 765242 SNPs and 146886 ins-dels were detected in the current study providing an extensive set of data for future studies of genetic mapping and selective breeding. In summary, these results will provides deep insight into the molecular basis of individual growth variation in marine invertebrates, and be valuable for understanding the physiological differences of growth process.

Transcriptome analysis of the sea cucumber (Apostichopus japonicus with variation in individual growth.

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Lei Gao

Full Text Available The sea cucumber (Apostichopus japonicus is an economically important aquaculture species in China. However, the serious individual growth variation often caused financial losses to farmers and the genetic mechanisms are poorly understood. In the present study, the extensively analysis at the transcriptome level for individual growth variation in sea cucumber was carried out. A total of 118946 unigenes were assembled from 255861 transcripts, with N50 of 1700. Of all unigenes, about 23% were identified with at least one significant match to known databases. In all four pair of comparison, 1840 genes were found to be expressed differently. Global hypometabolism was found to be occurred in the slow growing population, based on which the hypothesis was raised that growth retardation in individual growth variation of sea cucumber is one type of dormancy which is used to be against to adverse circumstances. Besides, the pathways such as ECM-receptor interaction and focal adhesion were enriched in the maintenance of cell and tissue structure and communication. Further, 76645 SSRs, 765242 SNPs and 146886 ins-dels were detected in the current study providing an extensive set of data for future studies of genetic mapping and selective breeding. In summary, these results will provides deep insight into the molecular basis of individual growth variation in marine invertebrates, and be valuable for understanding the physiological differences of growth process.

Gene expression variation resolves species and individual strains among coral-associated dinoflagellates within the genus Symbiodinium

KAUST Repository

Parkinson, John Everett; Baumgarten, Sebastian; Michell, Craig; Baums, Iliana B.; LaJeunesse, Todd C.; Voolstra, Christian R.

2016-01-01

Reef-building corals depend on symbiotic mutualisms with photosynthetic dinoflagellates in the genus Symbiodinium. This large microalgal group comprises many highly divergent lineages (“Clades A-I”) and hundreds of undescribed species. Given their ecological importance, efforts have turned to genomic approaches to characterize the functional ecology of Symbiodinium. To date, investigators have only compared gene expression between representatives from separate clades—the equivalent of contrasting genera or families in other dinoflagellate groups—making it impossible to distinguish between clade-level and species-level functional differences. Here, we examined the transcriptomes of four species within one Symbiodinium clade (Clade B) at ~20,000 orthologous genes, as well as multiple isoclonal cell lines within species (i.e. cultured strains). These species span two major adaptive radiations within Clade B, each encompassing both host-specialized and ecologically cryptic taxa. Species-specific expression differences were consistently enriched for photosynthesis-related genes, likely reflecting selection pressures driving niche diversification. Transcriptional variation among strains involved fatty acid metabolism and biosynthesis pathways. Such differences among individuals are potentially a major source of physiological variation, contributing to the functional diversity of coral holobionts composed of unique host-symbiont genotype pairings. Our findings expand the genomic resources available for this important symbiont group and emphasize the power of comparative transcriptomics as a method for studying speciation processes and inter-individual variation in non-model organisms.

Gene expression variation resolves species and individual strains among coral-associated dinoflagellates within the genus Symbiodinium

KAUST Repository

Parkinson, John Everett

2016-02-11

Reef-building corals depend on symbiotic mutualisms with photosynthetic dinoflagellates in the genus Symbiodinium. This large microalgal group comprises many highly divergent lineages (“Clades A-I”) and hundreds of undescribed species. Given their ecological importance, efforts have turned to genomic approaches to characterize the functional ecology of Symbiodinium. To date, investigators have only compared gene expression between representatives from separate clades—the equivalent of contrasting genera or families in other dinoflagellate groups—making it impossible to distinguish between clade-level and species-level functional differences. Here, we examined the transcriptomes of four species within one Symbiodinium clade (Clade B) at ~20,000 orthologous genes, as well as multiple isoclonal cell lines within species (i.e. cultured strains). These species span two major adaptive radiations within Clade B, each encompassing both host-specialized and ecologically cryptic taxa. Species-specific expression differences were consistently enriched for photosynthesis-related genes, likely reflecting selection pressures driving niche diversification. Transcriptional variation among strains involved fatty acid metabolism and biosynthesis pathways. Such differences among individuals are potentially a major source of physiological variation, contributing to the functional diversity of coral holobionts composed of unique host-symbiont genotype pairings. Our findings expand the genomic resources available for this important symbiont group and emphasize the power of comparative transcriptomics as a method for studying speciation processes and inter-individual variation in non-model organisms.

Individual variation in social aggression and the probability of inheritance: theory and a field test.

Science.gov (United States)

Cant, Michael A; Llop, Justine B; Field, Jeremy

2006-06-01

Recent theory suggests that much of the wide variation in individual behavior that exists within cooperative animal societies can be explained by variation in the future direct component of fitness, or the probability of inheritance. Here we develop two models to explore the effect of variation in future fitness on social aggression. The models predict that rates of aggression will be highest toward the front of the queue to inherit and will be higher in larger, more productive groups. A third prediction is that, in seasonal animals, aggression will increase as the time available to inherit the breeding position runs out. We tested these predictions using a model social species, the paper wasp Polistes dominulus. We found that rates of both aggressive "displays" (aimed at individuals of lower rank) and aggressive "tests" (aimed at individuals of higher rank) decreased down the hierarchy, as predicted by our models. The only other significant factor affecting aggression rates was date, with more aggression observed later in the season, also as predicted. Variation in future fitness due to inheritance rank is the hidden factor accounting for much of the variation in aggressiveness among apparently equivalent individuals in this species.

Effect of culture methods on individual variation in the growth of sea cucumber Apostichopus japonicus within a cohort and family

Science.gov (United States)

Qiu, Tianlong; Zhang, Libin; Zhang, Tao; Bai, Yucen; Yang, Hongsheng

2014-07-01

There is substantial individual variation in the growth rates of sea cucumber Apostichopus japonicus individuals. This necessitates additional work to grade the seed stock and lengthens the production period. We evaluated the influence of three culture methods (free-mixed, isolated-mixed, isolated-alone) on individual variation in growth and assessed the relationship between feeding, energy conversion efficiency, and individual growth variation in individually cultured sea cucumbers. Of the different culture methods, animals grew best when reared in the isolated-mixed treatment (i.e., size classes were held separately), though there was no difference in individual variation in growth between rearing treatment groups. The individual variation in growth was primarily attributed to genetic factors. The difference in food conversion efficiency caused by genetic differences among individuals was thought to be the origin of the variance. The level of individual growth variation may be altered by interactions among individuals and environmental heterogeneity. Our results suggest that, in addition to traditional seed grading, design of a new kind of substrate that changes the spatial distribution of sea cucumbers would effectively enhance growth and reduce individual variation in growth of sea cucumbers in culture.

Ontogenetic and among-individual variation in foraging strategies of northeast Pacific white sharks based on stable isotope analysis.

Science.gov (United States)

Kim, Sora L; Tinker, M Tim; Estes, James A; Koch, Paul L

2012-01-01

There is growing evidence for individuality in dietary preferences and foraging behaviors within populations of various species. This is especially important for apex predators, since they can potentially have wide dietary niches and a large impact on trophic dynamics within ecosystems. We evaluate the diet of an apex predator, the white shark (Carcharodon carcharias), by measuring the stable carbon and nitrogen isotope composition of vertebral growth bands to create lifetime records for 15 individuals from California. Isotopic variations in white shark diets can reflect within-region differences among prey (most importantly related to trophic level), as well as differences in baseline values among the regions in which sharks forage, and both prey and habitat preferences may shift with age. The magnitude of isotopic variation among sharks in our study (>5‰ for both elements) is too great to be explained solely by geographic differences, and so must reflect differences in prey choice that may vary with sex, size, age and location. Ontogenetic patterns in δ(15)N values vary considerably among individuals, and one third of the population fit each of these descriptions: 1) δ(15)N values increased throughout life, 2) δ(15)N values increased to a plateau at ∼5 years of age, and 3) δ(15)N values remained roughly constant values throughout life. Isotopic data for the population span more than one trophic level, and we offer a qualitative evaluation of diet using shark-specific collagen discrimination factors estimated from a 3+ year captive feeding experiment (Δ(13)C(shark-diet) and Δ(15)N(shark-diet) equal 4.2‰ and 2.5‰, respectively). We assess the degree of individuality with a proportional similarity index that distinguishes specialists and generalists. The isotopic variance is partitioned among differences between-individual (48%), within-individuals (40%), and by calendar year of sub-adulthood (12%). Our data reveal substantial ontogenetic and

Ontogenetic and among-individual variation in foraging strategies of northeast Pacific white sharks based on stable isotope analysis

Science.gov (United States)

Kim, S.L.; Tinker, M. Tim; Estes, J.A.; Koch, P.L.

2012-01-01

There is growing evidence for individuality in dietary preferences and foraging behaviors within populations of various species. This is especially important for apex predators, since they can potentially have wide dietary niches and a large impact on trophic dynamics within ecosystems. We evaluate the diet of an apex predator, the white shark (Carcharodon carcharias), by measuring the stable carbon and nitrogen isotope composition of vertebral growth bands to create lifetime records for 15 individuals from California. Isotopic variations in white shark diets can reflect within-region differences among prey (most importantly related to trophic level), as well as differences in baseline values among the regions in which sharks forage, and both prey and habitat preferences may shift with age. The magnitude of isotopic variation among sharks in our study (>5‰ for both elements) is too great to be explained solely by geographic differences, and so must reflect differences in prey choice that may vary with sex, size, age and location. Ontogenetic patterns in δ15N values vary considerably among individuals, and one third of the population fit each of these descriptions: 1) δ15N values increased throughout life, 2) δ15N values increased to a plateau at ~5 years of age, and 3) δ15N values remained roughly constant values throughout life. Isotopic data for the population span more than one trophic level, and we offer a qualitative evaluation of diet using shark-specific collagen discrimination factors estimated from a 3+ year captive feeding experiment (Δ13Cshark-diet and Δ15Nshark-diet equal 4.2‰ and 2.5‰, respectively). We assess the degree of individuality with a proportional similarity index that distinguishes specialists and generalists. The isotopic variance is partitioned among differences between-individual (48%), within-individuals (40%), and by calendar year of sub-adulthood (12%). Our data reveal substantial ontogenetic and individual dietary

Ontogenetic and among-individual variation in foraging strategies of northeast Pacific white sharks based on stable isotope analysis.

Directory of Open Access Journals (Sweden)

Sora L Kim

Full Text Available There is growing evidence for individuality in dietary preferences and foraging behaviors within populations of various species. This is especially important for apex predators, since they can potentially have wide dietary niches and a large impact on trophic dynamics within ecosystems. We evaluate the diet of an apex predator, the white shark (Carcharodon carcharias, by measuring the stable carbon and nitrogen isotope composition of vertebral growth bands to create lifetime records for 15 individuals from California. Isotopic variations in white shark diets can reflect within-region differences among prey (most importantly related to trophic level, as well as differences in baseline values among the regions in which sharks forage, and both prey and habitat preferences may shift with age. The magnitude of isotopic variation among sharks in our study (>5‰ for both elements is too great to be explained solely by geographic differences, and so must reflect differences in prey choice that may vary with sex, size, age and location. Ontogenetic patterns in δ(15N values vary considerably among individuals, and one third of the population fit each of these descriptions: 1 δ(15N values increased throughout life, 2 δ(15N values increased to a plateau at ∼5 years of age, and 3 δ(15N values remained roughly constant values throughout life. Isotopic data for the population span more than one trophic level, and we offer a qualitative evaluation of diet using shark-specific collagen discrimination factors estimated from a 3+ year captive feeding experiment (Δ(13C(shark-diet and Δ(15N(shark-diet equal 4.2‰ and 2.5‰, respectively. We assess the degree of individuality with a proportional similarity index that distinguishes specialists and generalists. The isotopic variance is partitioned among differences between-individual (48%, within-individuals (40%, and by calendar year of sub-adulthood (12%. Our data reveal substantial ontogenetic and

Variation in thickness of the large cryosections cut for whole-body autoradiography

International Nuclear Information System (INIS)

Ito, Tsunao; Brill, A.B.

1991-01-01

A method to assess variation in thickness of the large cryosections for whole-body autoradiography (WBARG) was described, and the degree of intraslice and interslice variations were determined for our cryomicrotome system (LKB PMV-2250). Intraslice variation in thickness of the 180 x 80 mm cryosection was 0.72-0.92 μm within the range of section thickness for WBARG (15-50 μm), and interslice variation was 0.89-1.21 μm. These potential variations in section thickness should be kept in mind whenever working with quantitative WBARG. (author)

Seasonal variation of daily physical activity in individuals with heart failure

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Michael J. Shoemaker

2016-09-01

Full Text Available BackgroundPrevious studies indicate that seasonal variation affects daily physical activity (PA, but none have investigated this relationship in individuals with heart failure (HF who also have implanted cardioverter defibrillators and cardiac resynchronization therapy (ICD/CRT devices. The purpose of the present study was to determine if seasonal variation in temperature affects daily PA in patients with HF and ICD/CRTs.Patients and methodsSecondary analysis of data from 16 subjects with HF and Medtronic® ICD/CRT devices enrolled in a randomized trial investigating interventions to improve daily PA. Due to the rolling study enrollment, daily PA data for all subjects were not available for the entire time frame and were divided into two groups. Determination of seasonal variation of daily PA was determined using visual analysis of daily PA plotted with average temperature, autocorrelation, visual analysis of seasonal subseries plots and boxplot analysis, as well as Wilcoxon signed-rank tests.ResultsSubjects 1-8 demonstrated the greatest differences in daily PA during periods of seasonal transition whereas subjects 9-16 demonstrated the greatest variation in daily PA with greatest seasonal temperature difference. Wilcoxon signed-rank testing of the lowest and highest months for daily PA revealed median differences of 0.30 (p = 0.050 and 0.36 hours (p = 0.036 for subjects 1-8 and 9-16, with effect sizes of 0.69 and 0.74, respectively.ConclusionsSeasonal variation in mean temperature appears to affect daily PA in individuals with HF and ICD/CRT devices by a magnitude of 0.30-0.36 hours, which may need to be accounted for in future research investigating interventions to improve daily PA.

Measuring total health inequality: adding individual variation to group-level differences

Directory of Open Access Journals (Sweden)

Gakidou Emmanuela

2002-08-01

Full Text Available Abstract Background Studies have revealed large variations in average health status across social, economic, and other groups. No study exists on the distribution of the risk of ill-health across individuals, either within groups or across all people in a society, and as such a crucial piece of total health inequality has been overlooked. Some of the reason for this neglect has been that the risk of death, which forms the basis for most measures, is impossible to observe directly and difficult to estimate. Methods We develop a measure of total health inequality – encompassing all inequalities among people in a society, including variation between and within groups – by adapting a beta-binomial regression model. We apply it to children under age two in 50 low- and middle-income countries. Our method has been adopted by the World Health Organization and is being implemented in surveys around the world; preliminary estimates have appeared in the World Health Report (2000. Results Countries with similar average child mortality differ considerably in total health inequality. Liberia and Mozambique have the largest inequalities in child survival, while Colombia, the Philippines and Kazakhstan have the lowest levels among the countries measured. Conclusions Total health inequality estimates should be routinely reported alongside average levels of health in populations and groups, as they reveal important policy-related information not otherwise knowable. This approach enables meaningful comparisons of inequality across countries and future analyses of the determinants of inequality.

Modeling the growth of individuals in plant populations: local density variation in a strand population of Xanthium strumarium (Asteraceae).

Science.gov (United States)

Weiner, J; Kinsman, S; Williams, S

1998-11-01

We studied the growth of individual Xanthium strumarium plants growing at four naturally occurring local densities on a beach in Maine: (1) isolated plants, (2) pairs of plants ≤1 cm apart, (3) four plants within 4 cm of each other, and (4) discrete dense clumps of 10-39 plants. A combination of nondestructive measurements every 2 wk and parallel calibration harvests provided very good estimates of the growth in aboveground biomass of over 400 individual plants over 8 wk and afforded the opportunity to fit explicit growth models to 293 of them. There was large individual variation in growth and resultant size within the population and within all densities. Local crowding played a role in determining plant size within the population: there were significant differences in final size between all densities except pairs and quadruples, which were almost identical. Overall, plants growing at higher densities were more variable in growth and final size than plants growing at lower densities, but this was due to increased variation among groups (greater variation in local density and/or greater environmental heterogeneity), not to increased variation within groups. Thus, there was no evidence of size asymmetric competition in this population. The growth of most plants was close to exponential over the study period, but half the plants were slightly better fit by a sigmoidal (logistic) model. The proportion of plants better fit by the logistic model increased with density and with initial plant size. The use of explicit growth models over several growth intervals to describe stand development can provide more biological content and more statistical power than "growth-size" methods that analyze growth intervals separately.

Large observer variation of clinical assessment of dyspnoeic wheezing children.

Science.gov (United States)

Bekhof, Jolita; Reimink, Roelien; Bartels, Ine-Marije; Eggink, Hendriekje; Brand, Paul L P

2015-07-01

In children with acute dyspnoea, the assessment of severity of dyspnoea and response to treatment is often performed by different professionals, implying that knowledge of the interobserver variation of this clinical assessment is important. To determine intraobserver and interobserver variation in clinical assessment of children with dyspnoea. From September 2009 to September 2010, we recorded a convenience sample of 27 acutely wheezing children (aged 3 months-7 years) in the emergency department of a general teaching hospital in the Netherlands, on video before and after treatment with inhaled bronchodilators. These video recordings were independently assessed by nine observers scoring wheeze, prolonged expiratory phase, retractions, nasal flaring and a general assessment of dyspnoea on a Likert scale (0-10). Assessment was repeated after 2 weeks to evaluate intraobserver variation. We analysed 972 observations. Intraobserver reliability was the highest for supraclavicular retractions (κ 0.84) and moderate-to-substantial for other items (κ 0.49-0.65). Interobserver reliability was considerably worse, with κ3 points) was larger than the minimal important change (meaning that in 69% of observations a clinically important change after treatment cannot be distinguished from measurement error. Intraobserver variation is modest, and interobserver variation is large for most clinical findings in children with dyspnoea. The measurement error induced by this variation is too large to distinguish potentially clinically relevant changes in dyspnoea after treatment in two-thirds of observations. The poor interobserver reliability of clinical dyspnoea assessment in children limits its usefulness in clinical practice and research, and highlights the need to use more objective measurements in these patients. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Natural selection on individual variation in tolerance of gastrointestinal nematode infection.

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Adam D Hayward

2014-07-01

Full Text Available Hosts may mitigate the impact of parasites by two broad strategies: resistance, which limits parasite burden, and tolerance, which limits the fitness or health cost of increasing parasite burden. The degree and causes of variation in both resistance and tolerance are expected to influence host-parasite evolutionary and epidemiological dynamics and inform disease management, yet very little empirical work has addressed tolerance in wild vertebrates. Here, we applied random regression models to longitudinal data from an unmanaged population of Soay sheep to estimate individual tolerance, defined as the rate of decline in body weight with increasing burden of highly prevalent gastrointestinal nematode parasites. On average, individuals lost weight as parasite burden increased, but whereas some lost weight slowly as burden increased (exhibiting high tolerance, other individuals lost weight significantly more rapidly (exhibiting low tolerance. We then investigated associations between tolerance and fitness using selection gradients that accounted for selection on correlated traits, including body weight. We found evidence for positive phenotypic selection on tolerance: on average, individuals who lost weight more slowly with increasing parasite burden had higher lifetime breeding success. This variation did not have an additive genetic basis. These results reveal that selection on tolerance operates under natural conditions. They also support theoretical predictions for the erosion of additive genetic variance of traits under strong directional selection and fixation of genes conferring tolerance. Our findings provide the first evidence of selection on individual tolerance of infection in animals and suggest practical applications in animal and human disease management in the face of highly prevalent parasites.

The Right Superior Frontal Gyrus and Individual Variation in Proactive Control of Impulsive Response.

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Hu, Sien; Ide, Jaime S; Zhang, Sheng; Li, Chiang-Shan R

2016-12-14

A hallmark of cognitive control is the ability to rein in impulsive responses. Previously, we used a Bayesian model to describe trial-by-trial likelihood of the stop signal or p(Stop) and related regional activations to p(Stop) to response slowing in a stop signal task. Here, we characterized the regional processes of conflict anticipation in association with intersubject variation in impulse control in 114 young adults. We computed the stop signal reaction time (SSRT) and a measure of motor urgency, indexed by the reaction time (RT) difference between go and stop error trials or "GoRT - SERT," where GoRT is the go trial RT and SERT is the stop error RT. Motor urgency and SSRT were positively correlated across subjects. A linear regression identified regional activations to p(Stop), each in correlation with SSRT and motor urgency. We hypothesized that shared neural activities mediate the correlation between motor urgency and SSRT in proactive control of impulsivity. Activation of the ventromedial prefrontal cortex, posterior cingulate cortex and right superior frontal gyrus (SFG) during conflict anticipation correlated negatively with the SSRT. Activation of the right SFG also correlated negatively with GoRT - SERT. Therefore, activation of the right SFG was associated with more efficient response inhibition and less motor urgency. A mediation analysis showed that right SFG activation to conflict anticipation mediates the correlation between SSRT and motor urgency bidirectionally. The current results highlight a specific role of the right SFG in translating conflict anticipation to the control of impulsive response, which is consistent with earlier studies suggesting its function in action restraint. Individuals vary in impulse control. However, the neural bases underlying individual variation in proactive control of impulsive responses remain unknown. Here, in a large sample of young adults, we showed that activation of the right superior frontal gyrus (SFG

Modeling Individual Cyclic Variation in Human Behavior.

Science.gov (United States)

Pierson, Emma; Althoff, Tim; Leskovec, Jure

2018-04-01

Cycles are fundamental to human health and behavior. Examples include mood cycles, circadian rhythms, and the menstrual cycle. However, modeling cycles in time series data is challenging because in most cases the cycles are not labeled or directly observed and need to be inferred from multidimensional measurements taken over time. Here, we present Cyclic Hidden Markov Models (CyH-MMs) for detecting and modeling cycles in a collection of multidimensional heterogeneous time series data. In contrast to previous cycle modeling methods, CyHMMs deal with a number of challenges encountered in modeling real-world cycles: they can model multivariate data with both discrete and continuous dimensions; they explicitly model and are robust to missing data; and they can share information across individuals to accommodate variation both within and between individual time series. Experiments on synthetic and real-world health-tracking data demonstrate that CyHMMs infer cycle lengths more accurately than existing methods, with 58% lower error on simulated data and 63% lower error on real-world data compared to the best-performing baseline. CyHMMs can also perform functions which baselines cannot: they can model the progression of individual features/symptoms over the course of the cycle, identify the most variable features, and cluster individual time series into groups with distinct characteristics. Applying CyHMMs to two real-world health-tracking datasets-of human menstrual cycle symptoms and physical activity tracking data-yields important insights including which symptoms to expect at each point during the cycle. We also find that people fall into several groups with distinct cycle patterns, and that these groups differ along dimensions not provided to the model. For example, by modeling missing data in the menstrual cycles dataset, we are able to discover a medically relevant group of birth control users even though information on birth control is not given to the model.

Individual variation in habituation: behaviour over time toward different stimuli in threespine sticklebacks (Gasterosteus aculeatus)

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Bell, Alison M.; Peeke, Harman V.S.

2014-01-01

Habituation, or the relatively permanent waning of a response as a result of repeated stimulation, is a form of behavioural plasticity that allows animals to filter out irrelevant stimuli and to focus selectively on important stimuli. Individuals that fail to habituate might be at a disadvantage if they continue to respond to irrelevant stimuli; therefore, habituation can have adaptive significance. In this study we compared rates of behaviour over time toward three different ecologically-relevant stimuli (food, a male intruder and a gravid female) in threespine sticklebacks (Gasterosteus aculeatus). We detected evidence for habituation to the stimuli, and males in this study were especially aggressive toward both male and female conspecifics. Although there were some clear temporal patterns that could be detected by looking at average behaviour, not all individuals behaved in the same ‘average’ way. We detected substantial inter-individual variation in behaviour toward all three stimuli, inter-individual variation in rates of habituation to both male and female conspecifics, but no evidence for correlations between behaviours across stimuli (behavioural syndromes). These results suggest that individual animals vary in rates of habituation, and prompt hypotheses about the causes and consequences of variation in rates of habituation. PMID:25678715

Microclimate and Individual Variation in Pollinators: Flowering Plants are More than Their Flowers

OpenAIRE

Herrera, Carlos M.

1995-01-01

Variation in pollinator composition at the individual plant level is an important prerequisite for plant specialization on pollinators that does not seem to have been investigated previously. I studied variation in pollinator composition in a southeastern Spanish population of the insect-pollinated shrub Lavandula latifolia (Labiatae) and examined its correlates, with particular reference to the distinction between factors intrinsic (flower morphology, nectar standing crop, size of floral dis...

Selenium:Mercury Molar Ratios in Freshwater Fish from Tennessee: Individual, Species, and Geographical Variations have Implications for Management

Science.gov (United States)

Burger, Joanna; Gochfeld, Michael; Jeitner, C.; Donio, M.; Pittfield, T.

2014-01-01

Vertebrates, including humans, can experience adverse effects from mercury consumed in fish. Humans often prefer large predatory fish that bioaccumulate high mercury levels. Recent attention has focused on the role of selenium countering mercury toxicity, but there is little research on the selenium:mercury molar ratios in freshwater fish. We examine selenium:mercury molar ratios in freshwater fish from Tennessee at Poplar Creek which receives ongoing inputs of mercury from the Department of Energy’s Oak Ridge Y-12 facility. Our objective was to determine variation of the ratios within species that might affect the protectiveness of selenium against mercury toxicity. Within species, the ratio was correlated significantly and positively with fish length only for two species. There was great individual variation in the selenium:mercury molar ratio within each species, except striped bass. The lack of a clear relationship between the selenium:mercury molar ratio and fish length, and the intraspecific variation, suggests that it would be difficult to use the molar ratio in predicting either the risk from mercury toxicity or in devising consumption advisories. PMID:22456727

AIDS, individual behaviour and the unexplained remaining variation.

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Katz, Alison

2002-01-01

From the start of the AIDS pandemic, individual behaviour has been put forward, implicitly or explicitly, as the main explanatory concept for understanding the epidemiology of HIV infection and in particular for the rapid spread and high prevalence in sub-Saharan Africa. This has had enormous implications for the international response to AIDS and has heavily influenced public health policy and strategy and the design of prevention and care interventions at national, community and individual level. It is argued that individual behaviour alone cannot possibly account for the enormous variation in HIV prevalence between population groups, countries and regions and that the unexplained remaining variation has been neglected by the international AIDS community. Biological vulnerability to HIV due to seriously deficient immune systems has been ignored as a determinant of the high levels of infection in certain populations. This is in sharp contrast to well proven public health approaches to other infectious diseases. In particular, it is argued that poor nutrition and co-infection with the myriad of other diseases of poverty including tuberculosis, malaria, leishmaniasis and parasitic infections, have been neglected as root causes of susceptibility, infectiousness and high rates of transmission of HIV at the level of populations. Vulnerability in terms of non-biological factors such as labour migration, prostitution, exchange of sex for survival, population movements due to war and violence, has received some attention but the solutions proposed to these problems are also inappropriately focused on individual behaviour and suffer from the same neglect of economic and political root causes. As the foundation for the international community's response to the AIDS pandemic, explanations of HIV/AIDS epidemiology in terms of individual behaviour are not only grossly inadequate, they are highly stigmatising and may in some cases, be racist. They have diverted attention from

Variation between individual cows in in situ rumen degradation characteristics of maize and grass silages

NARCIS (Netherlands)

Ali, M.; Cone, J. W.; van Duinkerken, G.; Klop, A.; Blok, M. C.; Bruinenberg, M.; Khan, N. A.; Hendriks, W. H.

2016-01-01

Different numbers of animals have been used in different studies to cover the variation between individual animals in in situ rumen degradation characteristics of maize and grass silages. The objective of this study was to determine whether three cows are sufficient or not to cover the variation

Genomic variation landscape of the human gut microbiome

DEFF Research Database (Denmark)

Schloissnig, Siegfried; Arumugam, Manimozhiyan; Sunagawa, Shinichi

2013-01-01

Whereas large-scale efforts have rapidly advanced the understanding and practical impact of human genomic variation, the practical impact of variation is largely unexplored in the human microbiome. We therefore developed a framework for metagenomic variation analysis and applied it to 252 faecal...... polymorphism rates of 0.11 was more variable between gut microbial species than across human hosts. Subjects sampled at varying time intervals exhibited individuality and temporal stability of SNP variation patterns, despite considerable composition changes of their gut microbiota. This indicates...

Untangling individual variation in natural populations: ecological, genetic and epigenetic correlates of long-term inequality in herbivory.

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Herrera, C M; Bazaga, P

2011-04-01

Individual variation in ecologically important features of organisms is a crucial element in ecology and evolution, yet disentangling its underlying causes is difficult in natural populations. We applied a genomic scan approach using amplified fragment length polymorphism (AFLP) markers to quantify the genetic basis of long-term individual differences in herbivory by mammals at a wild population of the violet Viola cazorlensis monitored for two decades. In addition, methylation-sensitive amplified polymorphism (MSAP) analyses were used to investigate the association between browsing damage and epigenetic characteristics of individuals, an aspect that has been not previously explored for any wild plant. Structural equation modelling was used to identify likely causal structures linking genotypes, epigenotypes and herbivory. Individuals of V. cazorlensis differed widely in the incidence of browsing mammals over the 20-year study period. Six AFLP markers (1.6% of total) were significantly related to herbivory, accounting altogether for 44% of population-wide variance in herbivory levels. MSAP analyses revealed considerable epigenetic variation among individuals, and differential browsing damage was significantly related to variation in multilocus epigenotypes. In addition, variation across plants in epigenetic characteristics was related to variation in several herbivory-related AFLP markers. Statistical comparison of alternative causal models suggested that individual differences in herbivory are the outcome of a complex causal structure where genotypes and epigenotypes are interconnected and have direct and indirect effects on herbivory. Insofar as methylation states of MSAP markers influential on herbivory are transgenerationally heritable, herbivore-driven evolutionary changes at the study population will involve correlated changes in genotypic and epigenotypic distributions. © 2011 Blackwell Publishing Ltd.

Individual Variation in Children's Reading Comprehension across Digital Text Types

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Fesel, Sabine S.; Segers, Eliane; Verhoeven, Ludo

2018-01-01

The present study examined children's digital text comprehension of digital text types linear digital text vs hypertext, with or without graphical navigable overviews. We investigated to what extent individual variation in children's comprehension could be explained by lexical quality (word reading efficiency and vocabulary knowledge), cognitive…

A marker of biological age explains individual variation in the strength of the adult stress response.

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Andrews, Clare; Nettle, Daniel; Larriva, Maria; Gillespie, Robert; Reichert, Sophie; Brilot, Ben O; Bedford, Thomas; Monaghan, Pat; Spencer, Karen A; Bateson, Melissa

2017-09-01

The acute stress response functions to prioritize behavioural and physiological processes that maximize survival in the face of immediate threat. There is variation between individuals in the strength of the adult stress response that is of interest in both evolutionary biology and medicine. Age is an established source of this variation-stress responsiveness diminishes with increasing age in a range of species-but unexplained variation remains. Since individuals of the same chronological age may differ markedly in their pace of biological ageing, we asked whether biological age-measured here via erythrocyte telomere length-predicts variation in stress responsiveness in adult animals of the same chronological age. We studied two cohorts of European starlings in which we had previously manipulated the rate of biological ageing by experimentally altering the competition experienced by chicks in the fortnight following hatching. We predicted that individuals with greater developmental telomere attrition, and hence greater biological age, would show an attenuated corticosterone (CORT) response to an acute stressor when tested as adults. In both cohorts, we found that birds with greater developmental telomere attrition had lower peak CORT levels and a more negative change in CORT levels between 15 and 30 min following stress exposure. Our results, therefore, provide strong evidence that a measure of biological age explains individual variation in stress responsiveness: birds that were biologically older were less stress responsive. Our results provide a novel explanation for the phenomenon of developmental programming of the stress response: observed changes in stress physiology as a result of exposure to early-life adversity may reflect changes in ageing.

Measurement and Socio-Demographic Variation of Social Capital in a Large Population-Based Survey

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Nieminen, Tarja; Martelin, Tuija; Koskinen, Seppo; Simpura, Jussi; Alanen, Erkki; Harkanen, Tommi; Aromaa, Arpo

2008-01-01

Objectives: The main objective of this study was to describe the variation of individual social capital according to socio-demographic factors, and to develop a suitable way to measure social capital for this purpose. The similarity of socio-demographic variation between the genders was also assessed. Data and methods: The study applied…

Absolute consistency: individual versus population variation in annual-cycle schedules of a long-distance migrant bird.

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Jesse R Conklin

Full Text Available Flexibility in scheduling varies throughout an organism's annual cycle, reflecting relative temporal constraints and fitness consequences among life-history stages. Time-selection can act at different scales, either by limiting the range of alternative strategies in the population, or by increasing the precision of individual performance. We tracked individual bar-tailed godwits Limosa lapponica baueri for two full years (including direct observation during non-breeding seasons in New Zealand and geolocator tracking of round-trip migrations to Alaska to present a full annual-cycle view of molt, breeding, and migration schedules. At both population and individual scales, temporal variation was greater in post-breeding than pre-breeding stages, and greater in molts than in movements, but schedules did not tighten across successive stages of migration toward the breeding grounds. In general, individual godwits were quite consistent in timing of events throughout the year, and repeatability of pre-breeding movements was particularly high (r = 0.82-0.92. However, we demonstrate that r values misrepresent absolute consistency by confounding inter- and intra-individual variation; the biological significance of r values can only be understood when these are considered separately. By doing so, we show that some stages have considerable tolerance for alternative strategies within the population, whereas scheduling of northbound migratory movements was similar for all individuals. How time-selection simultaneously shapes both individual and population variation is central to understanding and predicting adaptive phenological responses to environmental change.

Temporal Variation of Large Scale Flows in the Solar Interior ...

Indian Academy of Sciences (India)

tribpo

Temporal Variation of Large Scale Flows in the Solar Interior. 355. Figure 2. Zonal and meridional components of the time-dependent residual velocity at a few selected depths as marked above each panel, are plotted as contours of constant velocity in the longitude-latitude plane. The left panels show the zonal component, ...

Possible individual variation in susceptibility to radiation-induced genetic changes

International Nuclear Information System (INIS)

Gentner, N.E.; Walker, J.A.

1990-01-01

Several studies have shown variation between individuals in radiosensitivity. A person could have a high level of cytogenetic indicator because of high exposure or high susceptibility. To relate spontaneous cytogenetic end-points to dose it is advisable to have a measure of both the spontaneous level and of induced susceptibility. These end points need to be compared in irradiated persons who have developed cancer versus those who have not, as a guide to what end points are appropriate for susceptibility to radiogenic cancer. The use of inbred rodent strains may not be appropriate to derive specific locus mutation data relevant to the human situation, in which large differences in susceptibility appear to exist. Variability in response because of differential DNA repair capacity should be kept in mind when evaluating existing human data. For accident situations, using acute exposures for testing susceptibility may be appropriate, but to be relevant to low dose, low dose rate exposures, more use of protracted dose delivery in testing is recommended. There is a need for international collaborative study where these different tests are done on the same donors at the same time. It might now be prudent for radiation protection to take into account the occurrence of critical groups in the population on the basis of their increased radiation sensitivity. (12 refs., 3 figs.)

Testing a key assumption in animal communication: between-individual variation in female visual systems alters perception of male signals

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Kelly L. Ronald

2017-12-01

Full Text Available Variation in male signal production has been extensively studied because of its relevance to animal communication and sexual selection. Although we now know much about the mechanisms that can lead to variation between males in the properties of their signals, there is still a general assumption that there is little variation in terms of how females process these male signals. Variation between females in signal processing may lead to variation between females in how they rank individual males, meaning that one single signal may not be universally attractive to all females. We tested this assumption in a group of female wild-caught brown-headed cowbirds (Molothrus ater, a species that uses a male visual signal (e.g. a wingspread display to make its mate-choice decisions. We found that females varied in two key parameters of their visual sensory systems related to chromatic and achromatic vision: cone densities (both total and proportions and cone oil droplet absorbance. Using visual chromatic and achromatic contrast modeling, we then found that this between-individual variation in visual physiology leads to significant between-individual differences in how females perceive chromatic and achromatic male signals. These differences may lead to variation in female preferences for male visual signals, which would provide a potential mechanism for explaining individual differences in mate-choice behavior.

Testing a key assumption in animal communication: between-individual variation in female visual systems alters perception of male signals.

Science.gov (United States)

Ronald, Kelly L; Ensminger, Amanda L; Shawkey, Matthew D; Lucas, Jeffrey R; Fernández-Juricic, Esteban

2017-12-15

Variation in male signal production has been extensively studied because of its relevance to animal communication and sexual selection. Although we now know much about the mechanisms that can lead to variation between males in the properties of their signals, there is still a general assumption that there is little variation in terms of how females process these male signals. Variation between females in signal processing may lead to variation between females in how they rank individual males, meaning that one single signal may not be universally attractive to all females. We tested this assumption in a group of female wild-caught brown-headed cowbirds ( Molothrus ater ), a species that uses a male visual signal (e.g. a wingspread display) to make its mate-choice decisions. We found that females varied in two key parameters of their visual sensory systems related to chromatic and achromatic vision: cone densities (both total and proportions) and cone oil droplet absorbance. Using visual chromatic and achromatic contrast modeling, we then found that this between-individual variation in visual physiology leads to significant between-individual differences in how females perceive chromatic and achromatic male signals. These differences may lead to variation in female preferences for male visual signals, which would provide a potential mechanism for explaining individual differences in mate-choice behavior. © 2017. Published by The Company of Biologists Ltd.

Macrophytes shape trophic niche variation among generalist fishes.

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Ivana Vejříková

Full Text Available Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation among generalist fishes is facilitated by the presence of macrophytes, which provides niches and predation shelter for fish and their prey items. Based on results from stable nitrogen (δ15N and carbon (δ13C isotopic mixing models, perch (Perca fluviatilis L. and rudd (Scardinius erythrophthalmus (L. showed larger individual variation (i.e., variance in trophic position in Milada as compared to Most, whereas no significant between-lake differences were observed for roach (Rutilus rutilus (L.. Contrary to our hypothesis, all the three species showed significantly lower individual variation in the relative reliance on littoral food resources in Milada than in Most. Rudd relied significantly more whereas perch and roach relied less on littoral food resources in Milada than in Most, likely due to prevalent herbivory by rudd and prevalent zooplanktivory by perch and roach in the macrophyte-rich Milada as compared to macrophyte-poor Most. Our study demonstrates how the succession of macrophyte vegetation, via its effects on the physical and biological complexity of the littoral zone and on the availability of small prey fish and zooplankton, can strongly influence individual niche variation among generalist fishes with different ontogenetic trajectories, and hence

Macrophytes shape trophic niche variation among generalist fishes

Science.gov (United States)

Vejřík, Lukáš; Šmejkal, Marek; Čech, Martin; Sajdlová, Zuzana; Frouzová, Jaroslava; Kiljunen, Mikko; Peterka, Jiří

2017-01-01

Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation among generalist fishes is facilitated by the presence of macrophytes, which provides niches and predation shelter for fish and their prey items. Based on results from stable nitrogen (δ15N) and carbon (δ13C) isotopic mixing models, perch (Perca fluviatilis L.) and rudd (Scardinius erythrophthalmus (L.)) showed larger individual variation (i.e., variance) in trophic position in Milada as compared to Most, whereas no significant between-lake differences were observed for roach (Rutilus rutilus (L.)). Contrary to our hypothesis, all the three species showed significantly lower individual variation in the relative reliance on littoral food resources in Milada than in Most. Rudd relied significantly more whereas perch and roach relied less on littoral food resources in Milada than in Most, likely due to prevalent herbivory by rudd and prevalent zooplanktivory by perch and roach in the macrophyte-rich Milada as compared to macrophyte-poor Most. Our study demonstrates how the succession of macrophyte vegetation, via its effects on the physical and biological complexity of the littoral zone and on the availability of small prey fish and zooplankton, can strongly influence individual niche variation among generalist fishes with different ontogenetic trajectories, and hence the overall

Individuals and the variation needed for high species diversity in forest trees

Science.gov (United States)

James S. Clark

2010-01-01

In the past, explanations for high species diversity have been sought at the species level. Theory shows that coexistence requires substantial differences between species, but species-level data rarely provide evidence for such differences. Using data from forests in the southeastern United States, I show here that variation evident at the individual level provides for...

Individual identification and genetic variation of lions (Panthera leo from two protected areas in Nigeria.

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Talatu Tende

Full Text Available This survey was conducted in two protected areas in Nigeria to genetically identify individual lions and to determine the genetic variation within and between the populations. We used faecal sample DNA, a non-invasive alternative to the risky and laborious task of taking samples directly from the animals, often preceded by catching and immobilization. Data collection in Yankari Game Reserve (YGR spanned through a period of five years (2008 -2012, whereas data in Kainji Lake National Park (KLNP was gathered for a period of three years (2009, 2010 and 2012. We identified a minimum of eight individuals (2 males, 3 females, 3 unknown from YGR and a minimum of ten individuals (7 males, 3 females from KLNP. The two populations were found to be genetically distinct as shown by the relatively high fixation index (FST  = 0.17 with each population exhibiting signs of inbreeding (YGR FIS  = 0.49, KLNP FIS  = 0.38. The genetic differentiation between the Yankari and Kainji lions is assumed to result from large spatial geographic distance and physical barriers reducing gene flow between these two remaining wild lion populations in Nigeria. To mitigate the probable inbreeding depression in the lion populations within Nigeria it might be important to transfer lions between parks or reserves or to reintroduce lions from the zoos back to the wild.

Handheld mechanical nociceptive threshold testing in dairy cows - intra-individual variation, inter-observer agreement and variation over time.

Science.gov (United States)

Raundal, Peter M; Andersen, Pia H; Toft, Nils; Forkman, Björn; Munksgaard, Lene; Herskin, Mette S

2014-11-01

To examine the use of handheld methodology to assess mechanical nociceptive threshold (MNT) on cows kept loose-housed. Prospective randomized partial cross-over experimental study. A one-factor (test day) design was used to evaluate MNT over time. One hundred and fifteen healthy, loose-housed Danish Holstein cattle. We evaluated intra-individual variation, inter-observer agreement and variation over time of MNT using two handheld devices and two stimulation sites. Mechanical, ramped stimulations were performed with an algometer (6.5 mm diameter steel probe, 0-10.0 kgf) or an electronic von Frey device (plastic tip with diameter 0.8 mm, 0-1000 gf). Each cow received 5-6 consecutive stimulations within a 2 × 5 cm skin area on the dorsal or lateral aspect of the left third metatarsus until an avoidance reaction occurred. We investigated the difference in precision [expressed as coefficient of variation (CV)] between the combinations of devices and stimulation sites. The inter-observer agreement and the difference in MNT between test day 1, 3, 7, 10 and 24 were investigated for selected combinations. Data were analysed in mixed models and Bland-Altman as relevant. The CVs did not differ [range 0.34-0.52 (p = 0.1)]. Difference between observers (95% limits) was 0.2 kgf (2.8) and 4 gf (369) for the algometer and von Frey device, respectively. Mechanical nociceptive threshold increased from 361 on test day one to 495 gf on test day 24 (p < 0.01). All methods showed a high degree of intra-individual variation, and no combination of device and stimulation site showed superior precision. Mean difference between observers was low, and MNT was not consistent over time. Further development of the methods is required before they can be used in research to investigate possible relations between claw lesions and hyperalgesia. © 2014 The Authors Veterinary Anaesthesia and Analgesia published by John Wiley & Sons Ltd on behalf of Association of Veterinary Anaesthetists and the

Stability of Grid-Connected PV Inverters with Large Grid Impedance Variation

DEFF Research Database (Denmark)

Liserre, Marco; Teodorescu, Remus; Blaabjerg, Frede

2004-01-01

Photovoltaic (PV) inverters used in dispersed power generation of houses in the range of 1-5 kW are currently available from several manufactures. However, large grid impedance variation is challenging the control and the grid filter design in terms of stability. In fact the PV systems are well...... suited for loads connected in a great distance to the transformer (long wires) and the situation becomes even more difficult in low-developed remote areas characterized by low power transformers and long distribution wires with high grid impedance. Hence a theoretical analysis is needed because the grid...... impedance variation leads to dynamic and stability problems both in the low frequency range (around the current controller bandwidth frequency) as well as in the high frequency range (around the LCL-filter resonance frequency). In the low frequency range the possible variation of the impedance challenges...

The contribution of additive genetic variation to personality variation: heritability of personality.

Science.gov (United States)

Dochtermann, Ned A; Schwab, Tori; Sih, Andrew

2015-01-07

Individual animals frequently exhibit repeatable differences from other members of their population, differences now commonly referred to as 'animal personality'. Personality differences can arise, for example, from differences in permanent environmental effects--including parental and epigenetic contributors--and the effect of additive genetic variation. Although several studies have evaluated the heritability of behaviour, less is known about general patterns of heritability and additive genetic variation in animal personality. As overall variation in behaviour includes both the among-individual differences that reflect different personalities and temporary environmental effects, it is possible for personality to be largely genetically influenced even when heritability of behaviour per se is quite low. The relative contribution of additive genetic variation to personality variation can be estimated whenever both repeatability and heritability are estimated for the same data. Using published estimates to address this issue, we found that approximately 52% of animal personality variation was attributable to additive genetic variation. Thus, while the heritability of behaviour is often moderate or low, the heritability of personality is much higher. Our results therefore (i) demonstrate that genetic differences are likely to be a major contributor to variation in animal personality and (ii) support the phenotypic gambit: that evolutionary inferences drawn from repeatability estimates may often be justified. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Individual and contextual determinants of regional variation in prescription drug use: an analysis of administrative data from British Columbia.

Directory of Open Access Journals (Sweden)

Steven G Morgan

2010-12-01

Full Text Available Increasing attention is being paid to variations in the use of prescription drugs because their role in health care has grown to the point where their use can be considered a proxy for health system performance. Studies have shown that prescription drug use varies across regions in the US, UK, and Canada by more than would be predicted based on age and health status alone. In this paper, we explore the determinants of variations in the use of prescription drugs, drawing on health services theories of access to care.We conducted a cross-sectional analysis using population-based administrative health care data for British Columbia (BC, Canada. We used logistic and hierarchical regressions to analyze the effects of individual- and area-level determinants of use of prescriptions overall and rates of purchase of prescriptions from five therapeutic categories representing a range of indications: antihypertensives, statins, acid reducing drugs, opioid drugs, and antidepressants. To indicate the relative scale of regional variations and the importance of individual- and area-level variables in explaining them, we computed standardized rates of utilization for 49 local health areas in BC.We found that characteristics of individuals and the areas in which they live affect likelihood of prescription drug purchase. Individual-level factors influenced prescription drug purchases in ways generally consistent with behavioral models of health services use. Contextual variables exerted influences that differed by type of drug studied. Population health, education levels, and ethnic composition of local areas were associated with significant differences in the likelihood of purchasing medications. Relatively modest regional variations remained after both individual-level and area-level determinants were taken into account.The results of this study suggest that individual- and area-level factors should be considered when studying variations in the use of

Individual and contextual determinants of regional variation in prescription drug use: an analysis of administrative data from British Columbia.

Science.gov (United States)

Morgan, Steven G; Cunningham, Colleen M; Hanley, Gillian E

2010-12-29

Increasing attention is being paid to variations in the use of prescription drugs because their role in health care has grown to the point where their use can be considered a proxy for health system performance. Studies have shown that prescription drug use varies across regions in the US, UK, and Canada by more than would be predicted based on age and health status alone. In this paper, we explore the determinants of variations in the use of prescription drugs, drawing on health services theories of access to care. We conducted a cross-sectional analysis using population-based administrative health care data for British Columbia (BC), Canada. We used logistic and hierarchical regressions to analyze the effects of individual- and area-level determinants of use of prescriptions overall and rates of purchase of prescriptions from five therapeutic categories representing a range of indications: antihypertensives, statins, acid reducing drugs, opioid drugs, and antidepressants. To indicate the relative scale of regional variations and the importance of individual- and area-level variables in explaining them, we computed standardized rates of utilization for 49 local health areas in BC. We found that characteristics of individuals and the areas in which they live affect likelihood of prescription drug purchase. Individual-level factors influenced prescription drug purchases in ways generally consistent with behavioral models of health services use. Contextual variables exerted influences that differed by type of drug studied. Population health, education levels, and ethnic composition of local areas were associated with significant differences in the likelihood of purchasing medications. Relatively modest regional variations remained after both individual-level and area-level determinants were taken into account. The results of this study suggest that individual- and area-level factors should be considered when studying variations in the use of prescription drugs. Some

Omics approaches to individual variation: modeling networks and the virtual patient

OpenAIRE

Lehrach, Hans

2016-01-01

Every human is unique. We differ in our genomes, environment, behavior, disease history, and past and current medical treatment?a complex catalog of differences that often leads to variations in the way each of us responds to a particular therapy. We argue here that true personalization of drug therapies will rely on ?virtual patient? models based on a detailed characterization of the individual patient by molecular, imaging, and sensor techniques. The models will be based, wherever possible,...

Variation in sensory profile between individual Rainbow trout from the same production batch

DEFF Research Database (Denmark)

Hyldig, Grethe; Green-Petersen, Ditte

The variation in sensory properties between individual Rainbow trout (Oncorhynchus mykiss) belonging to the same aquaculture production batch was explored by using objective sensory profiling on minced and heat treated fillets. Additionally, Quality Index, mechanical texture, pH, fat and water...... content were measured. 30 fish, all from the same production batch, were sampled at three different times making three groups (ten fish each time). The results showed differences in the sensory profile between individual fish within all three groups. Also sensory differences between the three groups...... of fish were found. Similar differences in mechanical texture were found between individuals in two of the three groups and between the groups. No differences were found in Quality Index neither between individuals nor groups. A significant correlation between lipid content and firm texture was observed...

Efficient inference of population size histories and locus-specific mutation rates from large-sample genomic variation data.

Science.gov (United States)

Bhaskar, Anand; Wang, Y X Rachel; Song, Yun S

2015-02-01

With the recent increase in study sample sizes in human genetics, there has been growing interest in inferring historical population demography from genomic variation data. Here, we present an efficient inference method that can scale up to very large samples, with tens or hundreds of thousands of individuals. Specifically, by utilizing analytic results on the expected frequency spectrum under the coalescent and by leveraging the technique of automatic differentiation, which allows us to compute gradients exactly, we develop a very efficient algorithm to infer piecewise-exponential models of the historical effective population size from the distribution of sample allele frequencies. Our method is orders of magnitude faster than previous demographic inference methods based on the frequency spectrum. In addition to inferring demography, our method can also accurately estimate locus-specific mutation rates. We perform extensive validation of our method on simulated data and show that it can accurately infer multiple recent epochs of rapid exponential growth, a signal that is difficult to pick up with small sample sizes. Lastly, we use our method to analyze data from recent sequencing studies, including a large-sample exome-sequencing data set of tens of thousands of individuals assayed at a few hundred genic regions. © 2015 Bhaskar et al.; Published by Cold Spring Harbor Laboratory Press.

The association of environmental, individual factors, and dopamine pathway gene variation with smoking cessation.

Science.gov (United States)

Li, Suyun; Wang, Qiang; Pan, Lulu; Yang, Xiaorong; Li, Huijie; Jiang, Fan; Zhang, Nan; Han, Mingkui; Jia, Chongqi

2017-09-01

This study aimed to examine whether dopamine (DA) pathway gene variation were associated with smoking cessation, and compare the relative importance of infulence factors on smoking cessation. Participants were recruited from 17 villages of Shandong Province, China. Twenty-five single nucleotide polymorphisms in 8 DA pathway genes were genotyped. Weighted gene score of each gene was used to analyze the whole gene effect. Logistic regression was used to calculate odds ratios (OR) of the total gene score for smoking cessation. Dominance analysis was employed to compare the relative importance of individual, heaviness of smoking, psychological and genetic factors on smoking cessation. 415 successful spontaneous smoking quitters served as the cases, and 404 unsuccessful quitters served as the controls. A significant negative association of total DA pathway gene score and smoking cessation was observed (p smoking cessation was heaviness of smoking score (42%), following by individual (40%), genetic (10%) and psychological score (8%). In conclusion, although the DA pathway gene variation was significantly associated with successful smoking cessation, heaviness of smoking and individual factors had bigger effect than genetic factors on smoking cessation.

Midsagittal brain variation and MRI shape analysis of the precuneus in adult individuals

Science.gov (United States)

Bruner, Emiliano; Rangel de Lázaro, Gizéh; de la Cuétara, José Manuel; Martín-Loeches, Manuel; Colom, Roberto; Jacobs, Heidi I L

2014-01-01

Recent analyses indicate that the precuneus is one of the main centres of integration in terms of functional and structural processes within the human brain. This neuroanatomical element is formed by different subregions, involved in visuo-spatial integration, memory and self-awareness. We analysed the midsagittal brain shape in a sample of adult humans (n = 90) to evidence the patterns of variability and geometrical organization of this area. Interestingly, the major brain covariance pattern within adult humans is strictly associated with the relative proportions of the precuneus. Its morphology displays a marked individual variation, both in terms of geometry (mostly in its longitudinal dimensions) and anatomy (patterns of convolution). No patent differences are evident between males and females, and the allometric effect of size is minimal. However, in terms of morphology, the precuneus does not represent an individual module, being influenced by different neighbouring structures. Taking into consideration the apparent involvement of the precuneus in higher-order human brain functions and evolution, its wide variation further stresses the important role of these deep parietal areas in modern neuroanatomical organization. PMID:24397462

Inter-donor variation in cell subset specific immune signaling responses in healthy individuals.

Science.gov (United States)

Longo, Diane M; Louie, Brent; Wang, Ena; Pos, Zoltan; Marincola, Francesco M; Hawtin, Rachael E; Cesano, Alessandra

2012-01-01

Single cell network profiling (SCNP) is a multi-parameter flow cytometry based approach that allows for the simultaneous interrogation of intracellular signaling pathways in multiple cell subpopulations within heterogeneous tissues, without the need for individual cell subset isolation. Thus, the technology is extremely well-suited for characterizing the multitude of interconnected signaling pathways and immune cell subpopulations that regulate the function of the immune system. Recently, SCNP was applied to generate a functional map of the healthy human immune cell signaling network by profiling immune signaling pathways downstream of 12 immunomodulators in 7 distinct immune cell subsets within peripheral blood mononuclear cells (PBMCs) from 60 healthy donors. In the study reported here, the degree of inter-donor variation in the magnitude of the immune signaling responses was analyzed. The highest inter-donor differences in immune signaling pathway activity occurred following perturbation of the immune signaling network, rather than in basal signaling. When examining the full panel of immune signaling responses, as one may expect, the overall degree of inter-donor variation was positively correlated (r = 0.727) with the magnitude of node response (i.e. a larger median signaling response was associated with greater inter-donor variation). However, when examining the degree of heterogeneity across cell subpopulations for individual signaling nodes, cell subset specificity in the degree of inter-donor variation was observed for several nodes. For such nodes, relatively weak correlations between inter-donor variation and the magnitude of the response were observed. Further, within the phenotypically distinct subpopulations, a fraction of the immune signaling responses had bimodal response profiles in which (a) only a portion of the cells had elevated phospho-protein levels following modulation and (b) the proportion of responsive cells varied by donor. These data

Body weight in relation to variation in body size of Oystercatchers Haematopus ostralegus

NARCIS (Netherlands)

Zwarts, L; Hulscher, JB; Koopman, K; Zegers, PM

1996-01-01

This paper analyses the relationships between body weight in the Oystercatcher and two measures of its body size, bill length and wing length. The weight variation between individuals due to differences in body size is nearly as large as the seasonal variation in body weight within individuals. Wing

Handheld mechanical nociceptive threshold testing in dairy cows – intra-individual variation, inter-observer agreement and variation over time

Science.gov (United States)

Raundal, Peter M; Andersen, Pia H; Toft, Nils; Forkman, Björn; Munksgaard, Lene; Herskin, Mette S

2014-01-01

Objective To examine the use of handheld methodology to assess mechanical nociceptive threshold (MNT) on cows kept loose-housed. Study design Prospective randomized partial cross-over experimental study. A one-factor (test day) design was used to evaluate MNT over time. Animals One hundred and fifteen healthy, loose-housed Danish Holstein cattle. Methods We evaluated intra-individual variation, inter-observer agreement and variation over time of MNT using two handheld devices and two stimulation sites. Mechanical, ramped stimulations were performed with an algometer (6.5 mm diameter steel probe, 0–10.0 kgf) or an electronic von Frey device (plastic tip with diameter 0.8 mm, 0–1000 gf). Each cow received 5–6 consecutive stimulations within a 2 × 5 cm skin area on the dorsal or lateral aspect of the left third metatarsus until an avoidance reaction occurred. We investigated the difference in precision [expressed as coefficient of variation (CV)] between the combinations of devices and stimulation sites. The inter-observer agreement and the difference in MNT between test day 1, 3, 7, 10 and 24 were investigated for selected combinations. Data were analysed in mixed models and Bland-Altman as relevant. Results The CVs did not differ [range 0.34–0.52 (p = 0.1)]. Difference between observers (95% limits) was 0.2 kgf (2.8) and 4 gf (369) for the algometer and von Frey device, respectively. Mechanical nociceptive threshold increased from 361 on test day one to 495 gf on test day 24 (p < 0.01). Conclusion and clinical relevance All methods showed a high degree of intra-individual variation, and no combination of device and stimulation site showed superior precision. Mean difference between observers was low, and MNT was not consistent over time. Further development of the methods is required before they can be used in research to investigate possible relations between claw lesions and hyperalgesia. PMID:24734991

Sensitivity of the scale partition for variational multiscale large-eddy simulation of channel flow

NARCIS (Netherlands)

Holmen, J.; Hughes, T.J.R.; Oberai, A.A.; Wells, G.N.

2004-01-01

The variational multiscale method has been shown to perform well for large-eddy simulation (LES) of turbulent flows. The method relies upon a partition of the resolved velocity field into large- and small-scale components. The subgrid model then acts only on the small scales of motion, unlike

An evolutionary ecology of individual differences

Science.gov (United States)

Dall, Sasha R. X.; Bell, Alison M.; Bolnick, Daniel I.; Ratnieks, Francis L. W.

2014-01-01

Individuals often differ in what they do. This has been recognised since antiquity. Nevertheless, the ecological and evolutionary significance of such variation is attracting widespread interest, which is burgeoning to an extent that is fragmenting the literature. As a first attempt at synthesis, we focus on individual differences in behaviour within populations that exceed the day-to-day variation in individual behaviour (i.e. behavioural specialisation). Indeed, the factors promoting ecologically relevant behavioural specialisation within natural populations are likely to have far-reaching ecological and evolutionary consequences. We discuss such individual differences from three distinct perspectives: individual niche specialisations, the division of labour within insect societies and animal personality variation. In the process, while recognising that each area has its own unique motivations, we identify a number of opportunities for productive ‘crossfertilisation’ among the (largely independent) bodies of work. We conclude that a complete understanding of evolutionarily and ecologically relevant individual differences must specify how ecological interactions impact the basic biological process (e.g. Darwinian selection, development and information processing) that underpin the organismal features determining behavioural specialisations. Moreover, there is likely to be covariation amongst behavioural specialisations. Thus, we sketch the key elements of a general framework for studying the evolutionary ecology of individual differences. PMID:22897772

Variations between world regions in individual health: a multilevel analysis of the role of socio-economic factors

NARCIS (Netherlands)

Witvliet, Margot I.; Kunst, Anton E.; Stronks, Karien; Arah, Onyebuchi A.

2012-01-01

Background: Living in a particular region might affect health. We aimed to assess variations between regions in individual health. The role of socio-economic factors in the associations was also investigated. Methods: World Health Survey data were analysed on 220 487 individuals. Main outcomes

Factors affecting individual foraging specialization and temporal diet stability across the range of a large "generalist" apex predator.

Science.gov (United States)

Rosenblatt, Adam E; Nifong, James C; Heithaus, Michael R; Mazzotti, Frank J; Cherkiss, Michael S; Jeffery, Brian M; Elsey, Ruth M; Decker, Rachel A; Silliman, Brian R; Guillette, Louis J; Lowers, Russell H; Larson, Justin C

2015-05-01

Individual niche specialization (INS) is increasingly recognized as an important component of ecological and evolutionary dynamics. However, most studies that have investigated INS have focused on the effects of niche width and inter- and intraspecific competition on INS in small-bodied species for short time periods, with less attention paid to INS in large-bodied reptilian predators and the effects of available prey types on INS. We investigated the prevalence, causes, and consequences of INS in foraging behaviors across different populations of American alligators (Alligator mississippiensis), the dominant aquatic apex predator across the southeast US, using stomach contents and stable isotopes. Gut contents revealed that, over the short term, although alligator populations occupied wide ranges of the INS spectrum, general patterns were apparent. Alligator populations inhabiting lakes exhibited lower INS than coastal populations, likely driven by variation in habitat type and available prey types. Stable isotopes revealed that over longer time spans alligators exhibited remarkably consistent use of variable mixtures of carbon pools (e.g., marine and freshwater food webs). We conclude that INS in large-bodied reptilian predator populations is likely affected by variation in available prey types and habitat heterogeneity, and that INS should be incorporated into management strategies to efficiently meet intended goals. Also, ecological models, which typically do not consider behavioral variability, should include INS to increase model realism and applicability.

Milk fat depression in dairy ewes fed fish oil: Might differences in rumen biohydrogenation, fermentation, or bacterial community explain the individual variation?

Science.gov (United States)

Frutos, P; Toral, P G; Belenguer, A; Hervás, G

2018-07-01

Dairy ewes show large individual variation in the extent of diet-induced milk fat depression (MFD) but reasons behind this variability remain uncertain. Previous results offered no convincing support for these differences being related to relevant changes in the milk fatty acid (FA) profile, including potentially antilipogenic FA, or in the transcript abundance of candidate genes involved in mammary lipogenesis. Therefore, we hypothesized that alterations in the processes of rumen biohydrogenation and fermentation, as well as in the bacterial community structure, might account for individual variation in fish oil-induced MFD severity. To test this explanation, 15 ewes received a total mixed ration without lipid supplementation (control; n = 5) or supplemented with 20 g of fish oil/kg of dry matter [10 animals divided into those showing a strong (RESPON+; -25.4%; n = 5) or a mild (RESPON-; -7.7%; n = 5) decrease in milk fat concentration] for 5 wk. Rumen fermentation parameters, biohydrogenation metabolites, and bacterial structure and diversity were analyzed in rumen samples collected before and after treatments. Although the fish oil supplementation increased the concentration of demonstrated or putative antilipogenic FA (e.g., cis-9 16:1, cis-11 18:1, or trans-10,cis-12 CLA), surprisingly, none of them differed significantly in relation to the extent of MFD (i.e., between RESPON- and RESPON+), and this was the case only for a few minor FA (e.g., cis-6+7 16:1 or 17:0 anteiso). Changes in total volatile FA, acetate, and propionate concentrations were associated with MFD severity, with higher decreases in more susceptible animals. Individual responses were not related to shifts in rumen bacterial structure but some terminal restriction fragments compatible with Clostridiales, Ruminococcaceae, Lachnospiraceae, and Succiniclasticum showed greater abundances in RESPON-, whereas some others that may correspond to Prevotella, Mogibacterium, and Quinella-related spp. were

Multigrid solution of the Navier-Stokes equations at low speeds with large temperature variations

International Nuclear Information System (INIS)

Sockol, Peter M.

2003-01-01

Multigrid methods for the Navier-Stokes equations at low speeds and large temperature variations are investigated. The compressible equations with time-derivative preconditioning and preconditioned flux-difference splitting of the inviscid terms are used. Three implicit smoothers have been incorporated into a common multigrid procedure. Both full coarsening and semi-coarsening with directional fine-grid defect correction have been studied. The resulting methods have been tested on four 2D laminar problems over a range of Reynolds numbers on both uniform and highly stretched grids. Two of the three methods show efficient and robust performance over the entire range of conditions. In addition, none of the methods has any difficulty with the large temperature variations

Implications for risk assessment of host factors causing large pharmacokinetic variations

Energy Technology Data Exchange (ETDEWEB)

Vesell, E.S.

1985-12-01

Normal human subjects vary widely in their capacity to eliminate many drugs and environmental chemicals. These variations range in magnitude from fourfold to fortyfold depending on the drug and the population studied. Pharmacogenetics deals with only one of many host factors responsible for these large pharmacokinetic differences. Age, sex, diet and exposure to other drugs and chemicals, including oral contraceptives, ethanol and cigarette smoking, can alter the genetically determined rate at which a particular subject eliminates drugs and environmental chemicals. These elimination rates, therefore, are dynamic and change even in the same subject with time and condition. Regulatory legislation has only recently begun to recognize this very broad spectrum of human susceptibility and the existence of multiple special subgroups of particularly sensitive subjects. In setting standards for environmental chemicals, EPA and NIOSH have attempted to protect the most sensitive humans and should be encouraged to continue this policy. For some drugs and environmental chemicals, the commonly used safety factor of 100 may be too low; for these chemicals large, interindividual pharmacokinetic variations produced by pharmacogenetic and other host factors may make a safety factor of 400 or 500 more adequate.

Azimuthal angle correlations at large rapidities. Revisiting density variation mechanism

Energy Technology Data Exchange (ETDEWEB)

Gotsman, E. [Tel Aviv University, Department of Particle Physics, Raymond and Beverly Sackler Faculty of Exact Science, School of Physics and Astronomy, Tel Aviv (Israel); Levin, E. [Tel Aviv University, Department of Particle Physics, Raymond and Beverly Sackler Faculty of Exact Science, School of Physics and Astronomy, Tel Aviv (Israel); Universidad Tecnica Federico Santa Maria, Departemento de Fisica, Valparaiso (Chile); Centro Cientifico-Tecnologico de Valparaiso, Valparaiso (Chile)

2017-11-15

We discuss the angular correlation present in hadron-hadron collisions at large rapidity difference (anti α{sub S}y{sub 12} >> 1). We find that in the CGC/saturation approach the largest contribution stems from the density variation mechanism. Our principal results are that the odd Fourier harmonics (v{sub 2n+1}) decrease substantially as a function of y{sub 12}, while the even harmonics (v{sub 2n}) increase considerably with the growth of y{sub 12}. (orig.)

Large Interstellar Polarisation Survey. II. UV/optical study of cloud-to-cloud variations of dust in the diffuse ISM

Science.gov (United States)

Siebenmorgen, R.; Voshchinnikov, N. V.; Bagnulo, S.; Cox, N. L. J.; Cami, J.; Peest, C.

2018-03-01

It is well known that the dust properties of the diffuse interstellar medium exhibit variations towards different sight-lines on a large scale. We have investigated the variability of the dust characteristics on a small scale, and from cloud-to-cloud. We use low-resolution spectro-polarimetric data obtained in the context of the Large Interstellar Polarisation Survey (LIPS) towards 59 sight-lines in the Southern Hemisphere, and we fit these data using a dust model composed of silicate and carbon particles with sizes from the molecular to the sub-micrometre domain. Large (≥6 nm) silicates of prolate shape account for the observed polarisation. For 32 sight-lines we complement our data set with UVES archive high-resolution spectra, which enable us to establish the presence of single-cloud or multiple-clouds towards individual sight-lines. We find that the majority of these 35 sight-lines intersect two or more clouds, while eight of them are dominated by a single absorbing cloud. We confirm several correlations between extinction and parameters of the Serkowski law with dust parameters, but we also find previously undetected correlations between these parameters that are valid only in single-cloud sight-lines. We find that interstellar polarisation from multiple-clouds is smaller than from single-cloud sight-lines, showing that the presence of a second or more clouds depolarises the incoming radiation. We find large variations of the dust characteristics from cloud-to-cloud. However, when we average a sufficiently large number of clouds in single-cloud or multiple-cloud sight-lines, we always retrieve similar mean dust parameters. The typical dust abundances of the single-cloud cases are [C]/[H] = 92 ppm and [Si]/[H] = 20 ppm.

Genetically-based olfactory signatures persist despite dietary variation.

Directory of Open Access Journals (Sweden)

Jae Kwak

Full Text Available Individual mice have a unique odor, or odortype, that facilitates individual recognition. Odortypes, like other phenotypes, can be influenced by genetic and environmental variation. The genetic influence derives in part from genes of the major histocompatibility complex (MHC. A major environmental influence is diet, which could obscure the genetic contribution to odortype. Because odortype stability is a prerequisite for individual recognition under normal behavioral conditions, we investigated whether MHC-determined urinary odortypes of inbred mice can be identified in the face of large diet-induced variation. Mice trained to discriminate urines from panels of mice that differed both in diet and MHC type found the diet odor more salient in generalization trials. Nevertheless, when mice were trained to discriminate mice with only MHC differences (but on the same diet, they recognized the MHC difference when tested with urines from mice on a different diet. This indicates that MHC odor profiles remain despite large dietary variation. Chemical analyses of urinary volatile organic compounds (VOCs extracted by solid phase microextraction (SPME and analyzed by gas chromatography/mass spectrometry (GC/MS are consistent with this inference. Although diet influenced VOC variation more than MHC, with algorithmic training (supervised classification MHC types could be accurately discriminated across different diets. Thus, although there are clear diet effects on urinary volatile profiles, they do not obscure MHC effects.

Selection on Coding and Regulatory Variation Maintains Individuality in Major Urinary Protein Scent Marks in Wild Mice.

Directory of Open Access Journals (Sweden)

Michael J Sheehan

2016-03-01

Full Text Available Recognition of individuals by scent is widespread across animal taxa. Though animals can often discriminate chemical blends based on many compounds, recent work shows that specific protein pheromones are necessary and sufficient for individual recognition via scent marks in mice. The genetic nature of individuality in scent marks (e.g. coding versus regulatory variation and the evolutionary processes that maintain diversity are poorly understood. The individual signatures in scent marks of house mice are the protein products of a group of highly similar paralogs in the major urinary protein (Mup gene family. Using the offspring of wild-caught mice, we examine individuality in the major urinary protein (MUP scent marks at the DNA, RNA and protein levels. We show that individuality arises through a combination of variation at amino acid coding sites and differential transcription of central Mup genes across individuals, and we identify eSNPs in promoters. There is no evidence of post-transcriptional processes influencing phenotypic diversity as transcripts accurately predict the relative abundance of proteins in urine samples. The match between transcripts and urine samples taken six months earlier also emphasizes that the proportional relationships across central MUP isoforms in urine is stable. Balancing selection maintains coding variants at moderate frequencies, though pheromone diversity appears limited by interactions with vomeronasal receptors. We find that differential transcription of the central Mup paralogs within and between individuals significantly increases the individuality of pheromone blends. Balancing selection on gene regulation allows for increased individuality via combinatorial diversity in a limited number of pheromones.

Genome size variation affects song attractiveness in grasshoppers: evidence for sexual selection against large genomes.

Science.gov (United States)

Schielzeth, Holger; Streitner, Corinna; Lampe, Ulrike; Franzke, Alexandra; Reinhold, Klaus

2014-12-01

Genome size is largely uncorrelated to organismal complexity and adaptive scenarios. Genetic drift as well as intragenomic conflict have been put forward to explain this observation. We here study the impact of genome size on sexual attractiveness in the bow-winged grasshopper Chorthippus biguttulus. Grasshoppers show particularly large variation in genome size due to the high prevalence of supernumerary chromosomes that are considered (mildly) selfish, as evidenced by non-Mendelian inheritance and fitness costs if present in high numbers. We ranked male grasshoppers by song characteristics that are known to affect female preferences in this species and scored genome sizes of attractive and unattractive individuals from the extremes of this distribution. We find that attractive singers have significantly smaller genomes, demonstrating that genome size is reflected in male courtship songs and that females prefer songs of males with small genomes. Such a genome size dependent mate preference effectively selects against selfish genetic elements that tend to increase genome size. The data therefore provide a novel example of how sexual selection can reinforce natural selection and can act as an agent in an intragenomic arms race. Furthermore, our findings indicate an underappreciated route of how choosy females could gain indirect benefits. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

An integration of minimum local feature representation methods to recognize large variation of foods

Science.gov (United States)

Razali, Mohd Norhisham bin; Manshor, Noridayu; Halin, Alfian Abdul; Mustapha, Norwati; Yaakob, Razali

2017-10-01

Local invariant features have shown to be successful in describing object appearances for image classification tasks. Such features are robust towards occlusion and clutter and are also invariant against scale and orientation changes. This makes them suitable for classification tasks with little inter-class similarity and large intra-class difference. In this paper, we propose an integrated representation of the Speeded-Up Robust Feature (SURF) and Scale Invariant Feature Transform (SIFT) descriptors, using late fusion strategy. The proposed representation is used for food recognition from a dataset of food images with complex appearance variations. The Bag of Features (BOF) approach is employed to enhance the discriminative ability of the local features. Firstly, the individual local features are extracted to construct two kinds of visual vocabularies, representing SURF and SIFT. The visual vocabularies are then concatenated and fed into a Linear Support Vector Machine (SVM) to classify the respective food categories. Experimental results demonstrate impressive overall recognition at 82.38% classification accuracy based on the challenging UEC-Food100 dataset.

Conserved Genetic Architecture Underlying Individual Recombination Rate Variation in a Wild Population of Soay Sheep (Ovis aries).

Science.gov (United States)

Johnston, Susan E; Bérénos, Camillo; Slate, Jon; Pemberton, Josephine M

2016-05-01

Meiotic recombination breaks down linkage disequilibrium (LD) and forms new haplotypes, meaning that it is an important driver of diversity in eukaryotic genomes. Understanding the causes of variation in recombination rate is important in interpreting and predicting evolutionary phenomena and in understanding the potential of a population to respond to selection. However, despite attention in model systems, there remains little data on how recombination rate varies at the individual level in natural populations. Here we used extensive pedigree and high-density SNP information in a wild population of Soay sheep (Ovis aries) to investigate the genetic architecture of individual autosomal recombination rates. Individual rates were high relative to other mammal systems and were higher in males than in females (autosomal map lengths of 3748 and 2860 cM, respectively). The heritability of autosomal recombination rate was low but significant in both sexes (h(2) = 0.16 and 0.12 in females and males, respectively). In females, 46.7% of the heritable variation was explained by a subtelomeric region on chromosome 6; a genome-wide association study showed the strongest associations at locus RNF212, with further associations observed at a nearby ∼374-kb region of complete LD containing three additional candidate loci, CPLX1, GAK, and PCGF3 A second region on chromosome 7 containing REC8 and RNF212B explained 26.2% of the heritable variation in recombination rate in both sexes. Comparative analyses with 40 other sheep breeds showed that haplotypes associated with recombination rates are both old and globally distributed. Both regions have been implicated in rate variation in mice, cattle, and humans, suggesting a common genetic architecture of recombination rate variation in mammals. Copyright © 2016 by the Genetics Society of America.

Factors affecting individual foraging specialization and temporal diet stability across the range of a large “generalist” apex predator

Science.gov (United States)

Rosenblatt, Adam E.; Nifong, James C.; Heithaus, Michael R.; Mazzotti, Frank J.; Cherkiss, Michael S.; Jeffery, Brian M.; Elsey, Ruth M.; Decker, Rachel A.; Silliman, Brian R.; Guillette, Louis J.; Lowers, Russell H.; Larson, Justin C.

2015-01-01

Individual niche specialization (INS) is increasingly recognized as an important component of ecological and evolutionary dynamics. However, most studies that have investigated INS have focused on the effects of niche width and inter- and intraspecific competition on INS in small-bodied species for short time periods, with less attention paid to INS in large-bodied reptilian predators and the effects of available prey types on INS. We investigated the prevalence, causes, and consequences of INS in foraging behaviors across different populations of American alligators (Alligator mississippiensis), the dominant aquatic apex predator across the southeast US, using stomach contents and stable isotopes. Gut contents revealed that, over the short term, although alligator populations occupied wide ranges of the INS spectrum, general patterns were apparent. Alligator populations inhabiting lakes exhibited lower INS than coastal populations, likely driven by variation in habitat type and available prey types. Stable isotopes revealed that over longer time spans alligators exhibited remarkably consistent use of variable mixtures of carbon pools (e.g., marine and freshwater food webs). We conclude that INS in large-bodied reptilian predator populations is likely affected by variation in available prey types and habitat heterogeneity, and that INS should be incorporated into management strategies to efficiently meet intended goals. Also, ecological models, which typically do not consider behavioral variability, should include INS to increase model realism and applicability.

Variation in the expression of ergot alkaloids between individual tillers of perennial ryegrass

Science.gov (United States)

Mace, Wade; Lunn, Kristy; Lloyd-West, Catherine

2014-11-01

Epichloë fungal endophytes of cool season grasses are well known to produce a range of alkaloids of benefit to the host. Some of these compounds are advantageous to agriculture due to qualities that promote pasture persistence (e.g. the loline class of alkaloids confer insect protection) while others are detrimental to the wellbeing of grazing livestock. The ergot alkaloids (e.g. ergovaline), produced in ryegrass and tall fescue associations, causes poor animal health in farming regions in many countries around the world and further study is required to improve our knowledge on this class of compounds. Here we present the application of a quantitative LC-MS/MS (liquid chromatography coupled to mass spectrometry) method measuring eight ergot alkaloids (chanoclavine, agroclavine, elymoclavine, lysergol, lysergic acid, ergine, lysergyl alanine, ergovaline) produced by endophyte infected grasses, to monitor levels in individual tillers from multiple plants of a single cultivar of perennial ryegrass (Lolium perenne cv. ‘Grasslands Samson’) infected with a common toxic endophyte strain (Epichloë festucae var. lolii). Monitoring the expression in individual tillers allows an estimation of the variability within a plant (between tillers) as well as between plants. The study showed that there is significant variation in the concentration of the ergot alkaloids between tillers of a single plant, at or exceeding the level of variation observed between individual plants of a population. This result emphasizes the fundamental importance of robust experimental design and sampling procedures when alkaloid expression assessment is required and these need to be rigorously tailored to the hypothesis being tested.

Variation in the expression of ergot alkaloids between individual tillers of perennial ryegrass

Directory of Open Access Journals (Sweden)

Wade Jeffray Mace

2014-11-01

Full Text Available Epichloë fungal endophytes of cool season grasses are well known to produce a range of alkaloids of benefit to the host. Some of these compounds are advantageous to agriculture due to qualities that promote pasture persistence (e.g. the loline class of alkaloids confer insect protection while others are detrimental to the wellbeing of grazing livestock. The ergot alkaloids (e.g. ergovaline, produced in ryegrass and tall fescue associations, causes poor animal health in farming regions in many countries around the world and further study is required to improve our knowledge on this class of compounds. Here we present the application of a quantitative LC-MS/MS (liquid chromatography coupled to mass spectrometry method measuring eight ergot alkaloids (chanoclavine, agroclavine, elymoclavine, lysergol, lysergic acid, ergine, lysergyl alanine, ergovaline produced by endophyte infected grasses, to monitor levels in individual tillers from multiple plants of a single cultivar of perennial ryegrass (Lolium perenne cv. ‘Grasslands Samson’ infected with a common toxic endophyte strain (Epichloë festucae var. lolii. Monitoring the expression in individual tillers allows an estimation of the variability within a plant (between tillers as well as between plants.The study showed that there is significant variation in the concentration of the ergot alkaloids between tillers of a single plant, at or exceeding the level of variation observed between individual plants of a population. This result emphasizes the fundamental importance of robust experimental design and sampling procedures when alkaloid expression assessment is required and these need to be rigorously tailored to the hypothesis being tested.

Genetic Variation in the Scavenger Receptor MARCO and Its Association with Chronic Obstructive Pulmonary Disease and Lung Infection in 10,604 Individuals

DEFF Research Database (Denmark)

Thomsen, Mette; Nordestgaard, Børge G; Kobzik, Lester

2013-01-01

Background: MARCO (macrophage receptor with collagenous structure) is a dominant receptor for unopsonized particles and bacteria in the lungs. Reduced function of this receptor due to genetic variation may be associated with susceptibility to chronic obstructive pulmonary disease (COPD) and lung...... infection. Objectives: To identify novel genetic variants in MARCO that are associated with reduced lung function, or increased risk of COPD or lung infection. Methods: We first screened 760 individuals with extreme lung phenotypes in a large general population study to identify novel variants in the MARCO...... the entire cohort for these variants, we found low minor allele frequencies ranging from 0.005 to 5%. None of the individual MARCO genotypes were associated with reduced lung function, or risk of COPD or lung infection. H101Q heterozygotes had an increased odds ratio for sepsis of 2.2 (95% CI: 1...

Offspring fitness and individual optimization of clutch size

Science.gov (United States)

Both, C.; Tinbergen, J. M.; Noordwijk, A. J. van

1998-01-01

Within-year variation in clutch size has been claimed to be an adaptation to variation in the individual capacity to raise offspring. We tested this hypothesis by manipulating brood size to one common size, and predicted that if clutch size is individually optimized, then birds with originally large clutches have a higher fitness than birds with originally small clutches. No evidence was found that fitness was related to the original clutch size, and in this population clutch size is thus not related to the parental capacity to raise offspring. However, offspring from larger original clutches recruited better than their nest mates that came from smaller original clutches. This suggests that early maternal or genetic variation in viability is related to clutch size.

The role of individual variation in marine larval dispersal

KAUST Repository

Nanninga, Gerrit B.

2014-12-08

The exchange of individuals among patchy habitats plays a central role in spatial ecology and metapopulation dynamics. Dispersal is frequently observed to vary non-randomly within populations (e.g., short vs. long), indicating that variability among individuals may shape heterogeneity in patterns of connectivity. The concept of context- and condition-dependent dispersal describes the balance between the costs and benefits of dispersal that arises from the interaction of temporal and spatial landscape heterogeneity (the context) with phenotypic variability among individuals (the condition). While this hypothesis is widely accepted in terrestrial theory, it remains questionable to what extent the concept of adaptive dispersal strategies may apply to marine larval dispersal, a process that is largely determined by stochastic forces. Yet, larvae of many taxa exhibit strong navigational capabilities and there is mounting evidence of widespread intra-specific variability in biological traits that are potentially correlated with dispersal potential. While so far there are few known examples of real larval dispersal polymorphisms, intra-specifically variable dispersal strategies may be common in marine systems. Whether adaptive or not, it is becoming apparent that inter-individual heterogeneity in morphology, behavior, condition, and life history traits may have critical effects on population-level heterogeneity in dispersal. Here, we explore the eco-evolutionary causes and consequences of intrinsic and extrinsic variability on larval dispersal by synthesizing the existing literature and drawing conceptual parallels from terrestrial theory. We emphasize the potential importance of larval dispersal polymorphisms in marine population dynamics.

Individual, spatial and inter-sex variation in somatic growth: a study of Piaractus mesopotamicus (Characiformes: Serrasalmidae, a long-distance freshwater Neotropical migratory fish

Directory of Open Access Journals (Sweden)

Luzia da S. Lourenço

2017-06-01

Full Text Available ABSTRACT Growth is a fundamental biological process, driven by multiple endogenous (intra-individual and exogenous (environmental factors that maintain individual fitness and population stability. The current study aims to assess whether individual, spatial (headwaters and floodplains and inter-sex variation occurs in the growth of Piaractus mesopotamicus in the Cuiabá River basin. Samples were collected monthly from July 2006 to July 2007, at two areas in the Cuiabá River basin (headwaters and floodplain. Three growth models (individuals; individuals and sex factors; individuals and areas factors were developed and compared the fish growth parameters using Akaike information criterion (AIC. The best fit to the length-at-age data was obtained by a model that considered individual variation and sex. The theoretical maximum average length ( L∞ was 64.99 cm for females, and 63.23 cm for males. Females showed a growth rate (k of 0.230 yr-1and males of 0.196 yr-1. Thus, could be concluded that individual variability and sex were the main sources of variation in P. mesopotamicus somatic growth parameters.

Individual and age-related variation in chromatic contrast adaptation

Science.gov (United States)

Elliott, Sarah L.; Werner, John S.; Webster, Michael A.

2012-01-01

Precortical color channels are tuned primarily to the LvsM (stimulation of L and M cones varied, but S cone stimulation held constant) or SvsLM (stimulation of S cones varied, but L and M cone stimulation held constant) cone-opponent (cardinal) axes, but appear elaborated in the cortex to form higher-order mechanisms tuned to both cardinal and intermediate directions. One source of evidence for these higher-order mechanisms has been the selectivity of color contrast adaptation for noncardinal directions, yet the degree of this selectivity has varied widely across the small sample of observers tested in previous studies. This study explored the possible bases for this variation, and in particular tested whether it reflected age-related changes in the distribution or tuning of color mechanisms. Observers included 15 younger (18–22 years of age) and 15 older individuals (66–82), who adapted to temporal modulations along one of four chromatic axes (two cardinal and two intermediate axes) and then matched the hue and contrast of test stimuli lying along eight different directions in the equiluminant plane. All observers exhibited aftereffects that were selective for both the cardinal and intermediate directions, although selectivity was weaker for the intermediate axes. The degree of selectivity increased with the magnitude of adaptation for all axes, and thus adaptation strength alone may account for much of the variance in selectivity among observers. Older observers showed a stronger magnitude of adaptation thus, surprisingly, more conspicuous evidence for higher-order mechanisms. For both age groups the aftereffects were well predicted by response changes in chromatic channels with linear spectral sensitivities, and there was no evidence for weakened channel tuning with aging. The results suggest that higher-order mechanisms may become more exposed in observers or conditions in which the strength of adaptation is greater, and that both chromatic contrast

Host behaviour and physiology underpin individual variation in avian influenza virus infection in migratory Bewick's swans

NARCIS (Netherlands)

Hoye, B.J.; Fouchier, R.A.M; Klaassen, M.R.J.

2012-01-01

Individual variation in infection modulates both the dynamics of pathogens and their impact on host populations. It is therefore crucial to identify differential patterns of infection and understand the mechanisms responsible. Yet our understanding of infection heterogeneity in wildlife is limited,

PGen: large-scale genomic variations analysis workflow and browser in SoyKB.

Science.gov (United States)

Liu, Yang; Khan, Saad M; Wang, Juexin; Rynge, Mats; Zhang, Yuanxun; Zeng, Shuai; Chen, Shiyuan; Maldonado Dos Santos, Joao V; Valliyodan, Babu; Calyam, Prasad P; Merchant, Nirav; Nguyen, Henry T; Xu, Dong; Joshi, Trupti

2016-10-06

With the advances in next-generation sequencing (NGS) technology and significant reductions in sequencing costs, it is now possible to sequence large collections of germplasm in crops for detecting genome-scale genetic variations and to apply the knowledge towards improvements in traits. To efficiently facilitate large-scale NGS resequencing data analysis of genomic variations, we have developed "PGen", an integrated and optimized workflow using the Extreme Science and Engineering Discovery Environment (XSEDE) high-performance computing (HPC) virtual system, iPlant cloud data storage resources and Pegasus workflow management system (Pegasus-WMS). The workflow allows users to identify single nucleotide polymorphisms (SNPs) and insertion-deletions (indels), perform SNP annotations and conduct copy number variation analyses on multiple resequencing datasets in a user-friendly and seamless way. We have developed both a Linux version in GitHub ( https://github.com/pegasus-isi/PGen-GenomicVariations-Workflow ) and a web-based implementation of the PGen workflow integrated within the Soybean Knowledge Base (SoyKB), ( http://soykb.org/Pegasus/index.php ). Using PGen, we identified 10,218,140 single-nucleotide polymorphisms (SNPs) and 1,398,982 indels from analysis of 106 soybean lines sequenced at 15X coverage. 297,245 non-synonymous SNPs and 3330 copy number variation (CNV) regions were identified from this analysis. SNPs identified using PGen from additional soybean resequencing projects adding to 500+ soybean germplasm lines in total have been integrated. These SNPs are being utilized for trait improvement using genotype to phenotype prediction approaches developed in-house. In order to browse and access NGS data easily, we have also developed an NGS resequencing data browser ( http://soykb.org/NGS_Resequence/NGS_index.php ) within SoyKB to provide easy access to SNP and downstream analysis results for soybean researchers. PGen workflow has been optimized for the most

Sexual dimorphism and inter-individual variation in the rove beetle, Creophilus maxillosus L. (Col: Staphylinidae

Directory of Open Access Journals (Sweden)

Mohammad Shahbaz

2017-12-01

Full Text Available Sexual selection is expected to drive phenotypic differences between conspecific male and females, a widespread phenomenon known as sexual dimorphism. At the same time, individuals may exhibit some degree of intra-sexual variation. We examined the sexual dimorphism and inter-individual variation in different body parts of Creophilus maxillosus L. (Col: Staphylinidae, a cosmopolitan rove beetle commonly found on carrion. Male C. maxillosus had significantly wider head and pronotum, longer mandibles, and more distant eyes than females. The head width was positively correlated to mandible length, which may reflect stronger adductor muscles and higher bite force in larger individuals. The allometry of traits can be examined by plotting the logarithms of that specific trait against the logarithm of body size and determining the slope (b of the regression line. Isometry occurs when b=1, i.e. the ratio of given traits to body size remains constant across individuals. Negative allometry occurs when b1, so that larger individuals have disproportionately larger traits. A positive allometry was found in head width (b=1.32, mandible length (b=2.28, and ocular distance (b=1.49 of males. Our results show that, particularly head size, mandible length and ocular distance are probably under sexual selection in males, while traits such as eye size are isometric to body size. The potential role of these traits in male-male combat as well as female attractiveness has been frequently documented in different insect taxa. The striking similarities in patterns of sexual dimorphism among independently evolved insects indicate that common evolutionary force(s are probably at work.

Analysis of Inter- and Intra-individual Variation in Foraging Habits of the Endangered Hawaiian Petrel Using Stables Isotopes

Science.gov (United States)

Morra, K. E.; Ostrom, P. H.; Wiley, A. E.; James, H. F.; Stricker, C. A.; Gandhi, H.

2014-12-01

Stable isotope analysis of the endangered Hawaiian petrel's (Pterodroma sandwichensis, HAPE) feathers provides otherwise intractable information regarding non-breeding season foraging habits. Adult HAPE spend 3.5-6 months at sea during the non-breeding season, at which time they sequentially molt their flight feathers. Because feathers are metabolically inert once synthesized, they capture isotopic signals while they are grown, providing an opportunity to study foraging habits over time. Here we use stable hydrogen (δD), carbon (δ13C) and nitrogen (δ15N) isotopes to assess variation in foraging habits within and between individuals, and among four breeding colonies. δD is an indicator of prevalence of fish vs. invertebrates in the diet. In one analysis, we observed large variation in feather δD (125‰), with adults from Maui and Kauai having significantly higher δD values than corresponding hatch-year birds, indicating significant dietary differences between age groups. In a second analysis, we utilized δ13C and δ15N of Hawaii, Maui and Lanai adults, values which vary with trophic level and also at the base of the food web across HAPE's foraging range, potentially revealing information about feeding location, as well as diet. Furthermore, because the sequence of molt is known, we are able to determine whether individual foraging specialization (continued use of the same foraging behavior over time) exists in this species. To do this, we analyzed two primary feathers, P1 and P6, which reflect the beginning and the middle of the non-breeding season, respectively. We did not find significant differences in δ13C or δ15N between P1 and P6, suggesting consistent foraging habits within individuals over time. This provides evidence that individual foraging specialization exists within these populations. Analysis of a secondary feather grown late in the molt sequence would further illuminate the extent of foraging specialization. Finally, δ15N differs

Inter-doctor variations in the assessment of functional incapacities by insurance physicians

NARCIS (Netherlands)

Schellart, A.J.; Mulders, H.; Steenbeek, R.; Anema, J.R.; Kroneman, H.; Besseling, J.

2011-01-01

Background. The aim of this study was to determine the - largely unexplored - extent of systematic variation in the work disability assessment by Dutch insurance physicians (IPs) of employees on long-term sick leave, and to ascertain whether this variation was associated with the individual

Chaos in balance: non-linear measures of postural control predict individual variations in visual illusions of motion.

Directory of Open Access Journals (Sweden)

Deborah Apthorp

Full Text Available Visually-induced illusions of self-motion (vection can be compelling for some people, but they are subject to large individual variations in strength. Do these variations depend, at least in part, on the extent to which people rely on vision to maintain their postural stability? We investigated by comparing physical posture measures to subjective vection ratings. Using a Bertec balance plate in a brightly-lit room, we measured 13 participants' excursions of the centre of foot pressure (CoP over a 60-second period with eyes open and with eyes closed during quiet stance. Subsequently, we collected vection strength ratings for large optic flow displays while seated, using both verbal ratings and online throttle measures. We also collected measures of postural sway (changes in anterior-posterior CoP in response to the same visual motion stimuli while standing on the plate. The magnitude of standing sway in response to expanding optic flow (in comparison to blank fixation periods was predictive of both verbal and throttle measures for seated vection. In addition, the ratio between eyes-open and eyes-closed CoP excursions during quiet stance (using the area of postural sway significantly predicted seated vection for both measures. Interestingly, these relationships were weaker for contracting optic flow displays, though these produced both stronger vection and more sway. Next we used a non-linear analysis (recurrence quantification analysis, RQA of the fluctuations in anterior-posterior position during quiet stance (both with eyes closed and eyes open; this was a much stronger predictor of seated vection for both expanding and contracting stimuli. Given the complex multisensory integration involved in postural control, our study adds to the growing evidence that non-linear measures drawn from complexity theory may provide a more informative measure of postural sway than the conventional linear measures.

Bayesian Image Restoration Using a Large-Scale Total Patch Variation Prior

Directory of Open Access Journals (Sweden)

Yang Chen

2011-01-01

Full Text Available Edge-preserving Bayesian restorations using nonquadratic priors are often inefficient in restoring continuous variations and tend to produce block artifacts around edges in ill-posed inverse image restorations. To overcome this, we have proposed a spatial adaptive (SA prior with improved performance. However, this SA prior restoration suffers from high computational cost and the unguaranteed convergence problem. Concerning these issues, this paper proposes a Large-scale Total Patch Variation (LS-TPV Prior model for Bayesian image restoration. In this model, the prior for each pixel is defined as a singleton conditional probability, which is in a mixture prior form of one patch similarity prior and one weight entropy prior. A joint MAP estimation is thus built to ensure the iteration monotonicity. The intensive calculation of patch distances is greatly alleviated by the parallelization of Compute Unified Device Architecture(CUDA. Experiments with both simulated and real data validate the good performance of the proposed restoration.

Variation in Surficial Hydrated Minerals on Large Low-Albedo Asteroids

Science.gov (United States)

Rivkin, Andrew S.; Emery, Joshua P.; Howell, Ellen S.

2017-10-01

Observations of asteroids in the 3-µm spectral region, where absorptions diagnostic for hydrated minerals are found, show low-albedo asteroid spectra can be classified into at least 3 groups (Takir et al. 2013, Rivkin et al. 2015). While definitions of these groups vary between authors, they hold in common a group with spectra like what we see for CM/CI meteorites, one group with spectra like that of Ceres, and a group with spectra that have been interpreted as ice frost. The relationship between these groups is not yet clear. One possibility is that the spectrum reflects (no pun intended) the formation location for the asteroids and that a given object is undifferentiated and homogeneous in the composition of its hydrated minerals. However, models of the thermal and chemical evolution of large, low-albedo asteroids suggests that differentiation may be more common than we had thought, and impacts could exhume once-deep layers or expose complicated mixes of salts and silicates (for instance, Castillo-Rogez et al. LPSC 2017 model of Ceres). In this case, we might expect variation in the 3-µm spectral region to be seen on the surfaces of some objects as they rotate. We will present evidence for such variation in the spectrum of two large asteroids, 704 Interamnia (306 km diameter) and 324 Bamberga (220 km diameter). In the first case, Interamnia’s spectrum seems to have a combination of Ceres- and CM/CI-like features and has aspects where one or another component is dominant, while Bamberga’s spectrum is not easily placed in previously-defined groups.

Assessing Activity and Location of Individual Laying Hens in Large Groups Using Modern Technology.

Science.gov (United States)

Siegford, Janice M; Berezowski, John; Biswas, Subir K; Daigle, Courtney L; Gebhardt-Henrich, Sabine G; Hernandez, Carlos E; Thurner, Stefan; Toscano, Michael J

2016-02-02

Tracking individual animals within large groups is increasingly possible, offering an exciting opportunity to researchers. Whereas previously only relatively indistinguishable groups of individual animals could be observed and combined into pen level data, we can now focus on individual actors within these large groups and track their activities across time and space with minimal intervention and disturbance. The development is particularly relevant to the poultry industry as, due to a shift away from battery cages, flock sizes are increasingly becoming larger and environments more complex. Many efforts have been made to track individual bird behavior and activity in large groups using a variety of methodologies with variable success. Of the technologies in use, each has associated benefits and detriments, which can make the approach more or less suitable for certain environments and experiments. Within this article, we have divided several tracking systems that are currently available into two major categories (radio frequency identification and radio signal strength) and review the strengths and weaknesses of each, as well as environments or conditions for which they may be most suitable. We also describe related topics including types of analysis for the data and concerns with selecting focal birds.

Assessing Activity and Location of Individual Laying Hens in Large Groups Using Modern Technology

Directory of Open Access Journals (Sweden)

Janice M. Siegford

2016-02-01

Full Text Available Tracking individual animals within large groups is increasingly possible, offering an exciting opportunity to researchers. Whereas previously only relatively indistinguishable groups of individual animals could be observed and combined into pen level data, we can now focus on individual actors within these large groups and track their activities across time and space with minimal intervention and disturbance. The development is particularly relevant to the poultry industry as, due to a shift away from battery cages, flock sizes are increasingly becoming larger and environments more complex. Many efforts have been made to track individual bird behavior and activity in large groups using a variety of methodologies with variable success. Of the technologies in use, each has associated benefits and detriments, which can make the approach more or less suitable for certain environments and experiments. Within this article, we have divided several tracking systems that are currently available into two major categories (radio frequency identification and radio signal strength and review the strengths and weaknesses of each, as well as environments or conditions for which they may be most suitable. We also describe related topics including types of analysis for the data and concerns with selecting focal birds.

Assessment of the magnitude of geographical variations in the duration of non-work-related sickness absence by individual and contextual factors.

Science.gov (United States)

Torá-Rocamora, Isabel; Martínez, José Miguel; Gimeno, David; Alberti, Constança; Jardí, Josefina; Manzanera, Rafael; Benavides, Fernando G; Delclos, George

2015-01-01

To examine variation in the duration of non-work-related sickness absence (NWRSA) across geographical areas and the degree to which this variation can be explained by individual and/or contextual factors. All first NWRSA episodes ending in 2007 and 2010 were analyzed. Individual (diagnosis, age, sex) and contextual factors (healthcare resources, socioeconomic factors) were analyzed to assess how much of the geographical variation was explained by these factors. Median NWRSA durations in quartiles were mapped by counties in Catalonia. Multilevel Cox proportional hazard regression models with episodes nested within counties were fitted to quantify the magnitude of this variation. The proportional change in variance (PCV), median hazard ratios (MHR) and interquartile hazard ratios (IHR) were calculated. We found a geographical pattern in the duration of NWRSA, with longer duration in northwestern Catalonia. There was a small, but statistically significant, geographical variation in the duration of NWRSA, which mostly decreased after adjustment for individual factors in both women (PCV=34.98%, MHR=1.09, IHR=1.13 in 2007; PCV=34.68%, MHR=1.11, IHR=1.28 in 2010) and men (PCV=39.88%, MHR=1.10, IHR=1.27 in 2007; PCV=45.93%, MHR=1.10, IHR=1.25 in 2010); only in the case of women in 2010 was there a reduction in county-level variance due to contextual covariates (PCV=16.18%, MHR=1.12, IHR=1.32). County-level variation in the duration of NWRSA was small and was explained more by individual than by contextual variables. Knowledge of geographic differences in NWRSA duration is needed to plan specific programs and interventions to minimize these differences. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics

DEFF Research Database (Denmark)

Slik, J.W.Ferry; Paoli, Gary; McGuire, Krista

2013-01-01

.3 ± 109.3 Mg ha−1). Pan-tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature...

Magnitude determination for large underground nuclear explosions

Energy Technology Data Exchange (ETDEWEB)

Porter, Lawrence D [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1970-05-15

A method is presented for determining the local magnitudes for large underground nuclear explosions. The Gutenberg-Richter nomograph is applied to the peak amplitudes for 24 large underground nuclear explosions that took place in Nevada. The amplitudes were measured at 18 California Wood-Anderson stations located 150-810 km from the explosion epicenter. The variation of the individual station magnitudes and magnitude corrections and the variation of the average and rms error estimates in the magnitude determinations are examined with respect to distance, azimuth, and event location. The magnitude prediction capability of the Gutenberg-Richter nomograph is examined on the basis of these two criteria, and certain corrections are suggested. The azimuthal dependence of the individual station magnitudes is investigated, and corrections for the California stations are calculated. Statistical weighting schemes for two-component data are employed, and the assumptions and limitations in the use of peak amplitudes are discussed. (author)

Evaluation of within-litter birth weight variation in piglets

African Journals Online (AJOL)

VaZindove

2014-03-23

Mar 23, 2014 ... rates. Large weight variation at birth also requires the use of more pens, ... defined as the distribution of individual weights within a litter, has not been ..... the economic values of selection responses from the component traits ...

Narrow intra-individual variation of maternal thyroid function in pregnancy based on a longitudinal study on 132 women

DEFF Research Database (Denmark)

Boas, M.; Forman, Julie Lyng; Juul, A.

2009-01-01

BACKGROUND: Adaptive alterations in maternal physiology cause changes in thyroid hormone levels throughout pregnancy, and precise biochemical evaluation is thus highly dependent on gestation-specific reference intervals and expected intra-individual variation. OBJECTIVE: The aim of the study...... was the assessment of the intra-individual variation as well as the longitudinal course of thyroid hormones during normal pregnancy and factors that influence the normal reference range for thyroid function. For this purpose, a longitudinal statistical model was applied. DESIGN: In a cohort of 132 pregnant women......, serial blood samples were obtained and ultrasound scans were performed throughout pregnancy. METHODS: Serum levels of TSH, free and total thyroxine (T(4)), free and total triiodothyronine (T(3)) as well as autoantibodies against thyroid peroxidase and thyroglobulin were measured in 979 serum samples...

Big Data Analysis of Human Genome Variations

KAUST Repository

Gojobori, Takashi

2016-01-25

Since the human genome draft sequence was in public for the first time in 2000, genomic analyses have been intensively extended to the population level. The following three international projects are good examples for large-scale studies of human genome variations: 1) HapMap Data (1,417 individuals) (http://hapmap.ncbi.nlm.nih.gov/downloads/genotypes/2010-08_phaseII+III/forward/), 2) HGDP (Human Genome Diversity Project) Data (940 individuals) (http://www.hagsc.org/hgdp/files.html), 3) 1000 genomes Data (2,504 individuals) http://ftp.1000genomes.ebi.ac.uk/vol1/ftp/release/20130502/ If we can integrate all three data into a single volume of data, we should be able to conduct a more detailed analysis of human genome variations for a total number of 4,861 individuals (= 1,417+940+2,504 individuals). In fact, we successfully integrated these three data sets by use of information on the reference human genome sequence, and we conducted the big data analysis. In particular, we constructed a phylogenetic tree of about 5,000 human individuals at the genome level. As a result, we were able to identify clusters of ethnic groups, with detectable admixture, that were not possible by an analysis of each of the three data sets. Here, we report the outcome of this kind of big data analyses and discuss evolutionary significance of human genomic variations. Note that the present study was conducted in collaboration with Katsuhiko Mineta and Kosuke Goto at KAUST.

The neurobiology of individuality

Science.gov (United States)

de Bivort, Benjamin

2015-03-01

Individuals often display conspicuously different patterns of behavior, even when they are very closely related genetically. These differences give rise to our sense of individuality, but what is their molecular and neurobiological basis? Individuals that are nominally genetically identical differ at various molecular and neurobiological levels: cell-to-cell variation in somatic genomes, cell-to-cell variation in expression patterns, individual-to-individual variation in neuronal morphology and physiology, and individual-to-individual variation in patterns of brain activity. It is unknown which of these levels is fundamentally causal of behavioral differences. To investigate this problem, we use the fruit fly Drosophila melanogaster, whose genetic toolkit allows the manipulation of each of these mechanistic levels, and whose rapid lifecycle and small size allows for high-throughput automation of behavioral assays. This latter point is crucial; identifying inter-individual behavioral differences requires high sample sizes both within and across individual animals. Automated behavioral characterization is at the heart of our research strategy. In every behavior examined, individual flies have individual behavioral preferences, and we have begun to identify both neural genes and circuits that control the degree of behavioral variability between individuals.

Structure and mechanism of diet specialisation: testing models of individual variation in resource use with sea otters

Science.gov (United States)

Tinker, M. Tim; Guimarães, Paulo R.; Novak, Mark; Marquitti, Flavia Maria Darcie; Bodkin, James L.; Staedler, Michelle; Bentall, Gena B.; Estes, James A.

2012-01-01

Studies of consumer-resource interactions suggest that individual diet specialisation is empirically widespread and theoretically important to the organisation and dynamics of populations and communities. We used weighted networks to analyze the resource use by sea otters, testing three alternative models for how individual diet specialisation may arise. As expected, individual specialisation was absent when otter density was low, but increased at high-otter density. A high-density emergence of nested resource-use networks was consistent with the model assuming individuals share preference ranks. However, a density-dependent emergence of a non-nested modular network for ‘core’ resources was more consistent with the ‘competitive refuge’ model. Individuals from different diet modules showed predictable variation in rank-order prey preferences and handling times of core resources, further supporting the competitive refuge model. Our findings support a hierarchical organisation of diet specialisation and suggest individual use of core and marginal resources may be driven by different selective pressures.

Intra- and inter-individual variations of blood and urinary water-soluble vitamins in Japanese young adults consuming a semi-purified diet for 7 days.

Science.gov (United States)

Shibata, Katsumi; Fukuwatari, Tsutomu; Watanabe, Toshiaki; Nishimuta, Mamoru

2009-12-01

We have previously reported the levels of water-soluble vitamins in the blood and urine of Japanese young adults. In the present paper, to assess the variations in these water-soluble vitamin markers during the above experiment, we comprehensively determined the intra- and inter-individual variations of blood and urinary water-soluble vitamins to exactly the same amount of water-soluble vitamin intakes in the same experiment. The blood samples before breakfast and the 24-h urine samples were periodically collected from Japanese college male (n=10) and female (n=10) students consuming a semi-purified diet with water-soluble vitamins based on Japanese Dietary Reference Intakes for 7 d, and the intra- and inter-individual variations of blood and urinary water-soluble vitamins or their metabolites in blood and urine samples after adaptation were calculated. Although urinary excretion of vitamin B(12) and vitamin C showed high intra-individual variations in both males and females, other urinary vitamins and all blood vitamins showed less than 20% of within-subject coefficients of variance in either male or female. Those showing more than 20% of between-subject coefficients of variances in both male and female were blood vitamin B(6), vitamin B(12) and folate levels, and urinary vitamin B(1), vitamin B(2), vitamin B(12), nicotinamide metabolites, pantothenic acid, biotin and vitamin C. These results showed that oral administration of constant of water-soluble vitamins generally decreased intra-individual variation, while individual differences in urinary vitamin excretion were observed.

Canopy area of large trees explains aboveground biomass variations across neotropical forest landscapes

Science.gov (United States)

Meyer, Victoria; Saatchi, Sassan; Clark, David B.; Keller, Michael; Vincent, Grégoire; Ferraz, António; Espírito-Santo, Fernando; d'Oliveira, Marcus V. N.; Kaki, Dahlia; Chave, Jérôme

2018-06-01

Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new lidar-derived index, the large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this simple measure of forest structure representing the crown area of large canopy trees could consistently explain the landscape variations in forest volume and aboveground biomass (AGB) across a range of climate and edaphic conditions. To test this hypothesis, we assembled a unique dataset of high-resolution airborne light detection and ranging (lidar) and ground inventory data in nine undisturbed old-growth Neotropical forests, of which four had plots large enough (1 ha) to calibrate our model. We found that the LCA for trees greater than 27 m (˜ 25-30 m) in height and at least 100 m2 crown size in a unit area (1 ha), explains more than 75 % of total forest volume variations, irrespective of the forest biogeographic conditions. When weighted by average wood density of the stand, LCA can be used as an unbiased estimator of AGB across sites (R2 = 0.78, RMSE = 46.02 Mg ha-1, bias = -0.63 Mg ha-1). Unlike other lidar-derived metrics with complex nonlinear relations to biomass, the relationship between LCA and AGB is linear and remains unique across forest types. A comparison with tree inventories across the study sites indicates that LCA correlates best with the crown area (or basal area) of trees with diameter greater than 50 cm. The spatial invariance of the LCA-AGB relationship across the Neotropics suggests a remarkable regularity of forest structure across the landscape and a new technique for systematic monitoring of large trees for their contribution to AGB and changes associated with selective logging, tree mortality and other types of tropical forest disturbance and dynamics.

The Ecology of Exercise: Mechanisms Underlying Individual Variation in Behavior, Activity, and Performance: An Introduction to Symposium.

Science.gov (United States)

Killen, Shaun S; Calsbeek, Ryan; Williams, Tony D

2017-08-01

Wild animals often engage in intense physical activity while performing tasks vital for their survival and reproduction associated with foraging, avoiding predators, fighting, providing parental care, and migrating. In this theme issue we consider how viewing these tasks as "exercise"-analogous to that performed by human athletes-may help provide insight into the mechanisms underlying individual variation in these types of behaviors and the importance of physical activity in an ecological context. In this article and throughout this issue, we focus on four key questions relevant to the study of behavioral ecology that may be addressed by studying wild animal behavior from the perspective of exercise physiology: (1) How hard do individual animals work in response to ecological (or evolutionary) demands?; (2) Do lab-based studies of activity provide good models for understanding activity in free-living animals and individual variation in traits?; (3) Can animals work too hard during "routine" activities?; and (4) Can paradigms of "exercise" and "training" be applied to free-living animals? Attempts to address these issues are currently being facilitated by rapid technological developments associated with physiological measurements and the remote tracking of wild animals, to provide mechanistic insights into the behavior of free-ranging animals at spatial and temporal scales that were previously impossible. We further suggest that viewing the behaviors of non-human animals in terms of the physical exercise performed will allow us to fully take advantage of these technological advances, draw from knowledge and conceptual frameworks already in use by human exercise physiologists, and identify key traits that constrain performance and generate variation in performance among individuals. It is our hope that, by highlighting mechanisms of behavior and performance, the articles in this issue will spur on further synergies between physiologists and ecologists, to take

Genome Variation Map: a data repository of genome variations in BIG Data Center.

Science.gov (United States)

Song, Shuhui; Tian, Dongmei; Li, Cuiping; Tang, Bixia; Dong, Lili; Xiao, Jingfa; Bao, Yiming; Zhao, Wenming; He, Hang; Zhang, Zhang

2018-01-04

The Genome Variation Map (GVM; http://bigd.big.ac.cn/gvm/) is a public data repository of genome variations. As a core resource in the BIG Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences, GVM dedicates to collect, integrate and visualize genome variations for a wide range of species, accepts submissions of different types of genome variations from all over the world and provides free open access to all publicly available data in support of worldwide research activities. Unlike existing related databases, GVM features integration of a large number of genome variations for a broad diversity of species including human, cultivated plants and domesticated animals. Specifically, the current implementation of GVM not only houses a total of ∼4.9 billion variants for 19 species including chicken, dog, goat, human, poplar, rice and tomato, but also incorporates 8669 individual genotypes and 13 262 manually curated high-quality genotype-to-phenotype associations for non-human species. In addition, GVM provides friendly intuitive web interfaces for data submission, browse, search and visualization. Collectively, GVM serves as an important resource for archiving genomic variation data, helpful for better understanding population genetic diversity and deciphering complex mechanisms associated with different phenotypes. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Genome Variation Map: a data repository of genome variations in BIG Data Center

Science.gov (United States)

Tian, Dongmei; Li, Cuiping; Tang, Bixia; Dong, Lili; Xiao, Jingfa; Bao, Yiming; Zhao, Wenming; He, Hang

2018-01-01

Abstract The Genome Variation Map (GVM; http://bigd.big.ac.cn/gvm/) is a public data repository of genome variations. As a core resource in the BIG Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences, GVM dedicates to collect, integrate and visualize genome variations for a wide range of species, accepts submissions of different types of genome variations from all over the world and provides free open access to all publicly available data in support of worldwide research activities. Unlike existing related databases, GVM features integration of a large number of genome variations for a broad diversity of species including human, cultivated plants and domesticated animals. Specifically, the current implementation of GVM not only houses a total of ∼4.9 billion variants for 19 species including chicken, dog, goat, human, poplar, rice and tomato, but also incorporates 8669 individual genotypes and 13 262 manually curated high-quality genotype-to-phenotype associations for non-human species. In addition, GVM provides friendly intuitive web interfaces for data submission, browse, search and visualization. Collectively, GVM serves as an important resource for archiving genomic variation data, helpful for better understanding population genetic diversity and deciphering complex mechanisms associated with different phenotypes. PMID:29069473

Longwave thermal infrared spectral variability in individual rocks

Energy Technology Data Exchange (ETDEWEB)

Balick, Lee K [Los Alamos National Laboratory; Gillespie, Alan [UN. WASHINGTON; French, Andrew [USDA-ARS; Danilina, Iryna [UN. WASHINGTON

2008-01-01

A hyperspectral imaging spectrometer measuring in the longwave thermal infrared (7.6-11.6 {micro}m) with a spatial resolution less than 4 mm was used in the field to observe the variability of emissivity spectra within individual rocks. The rocks were obtained commercially, were on the order of 20 cm in size and were selected to have distinct spectral features: they include alabaster (gypsum), soapstone (steatite with talc), obsidian (volcanic glass), norite (plagioclase and orthopyroxene), and 'jasper' (silica with iron oxides). The advantages of using an imaging spectrometer to spectrally characterize these rocks are apparent. Large spectral variations were observed within individual rocks that may be attributed to roughness, surface geometry, and compositional variation. Non-imaging spectrometers would normally miss these variations as would small samples used in laboratory measurements, spatially averaged spectra can miss the optimum spectra for identification materials and spatially localized components of the rock can be obscured.

Identifying tagging SNPs for African specific genetic variation from the African Diaspora Genome.

Science.gov (United States)

Johnston, Henry Richard; Hu, Yi-Juan; Gao, Jingjing; O'Connor, Timothy D; Abecasis, Gonçalo R; Wojcik, Genevieve L; Gignoux, Christopher R; Gourraud, Pierre-Antoine; Lizee, Antoine; Hansen, Mark; Genuario, Rob; Bullis, Dave; Lawley, Cindy; Kenny, Eimear E; Bustamante, Carlos; Beaty, Terri H; Mathias, Rasika A; Barnes, Kathleen C; Qin, Zhaohui S

2017-04-21

A primary goal of The Consortium on Asthma among African-ancestry Populations in the Americas (CAAPA) is to develop an 'African Diaspora Power Chip' (ADPC), a genotyping array consisting of tagging SNPs, useful in comprehensively identifying African specific genetic variation. This array is designed based on the novel variation identified in 642 CAAPA samples of African ancestry with high coverage whole genome sequence data (~30× depth). This novel variation extends the pattern of variation catalogued in the 1000 Genomes and Exome Sequencing Projects to a spectrum of populations representing the wide range of West African genomic diversity. These individuals from CAAPA also comprise a large swath of the African Diaspora population and incorporate historical genetic diversity covering nearly the entire Atlantic coast of the Americas. Here we show the results of designing and producing such a microchip array. This novel array covers African specific variation far better than other commercially available arrays, and will enable better GWAS analyses for researchers with individuals of African descent in their study populations. A recent study cataloging variation in continental African populations suggests this type of African-specific genotyping array is both necessary and valuable for facilitating large-scale GWAS in populations of African ancestry.

Reconciling the Log-Linear and Non-Log-Linear Nature of the TSH-Free T4 Relationship: Intra-Individual Analysis of a Large Population.

Science.gov (United States)

Rothacker, Karen M; Brown, Suzanne J; Hadlow, Narelle C; Wardrop, Robert; Walsh, John P

2016-03-01

The TSH-T4 relationship was thought to be inverse log-linear, but recent cross-sectional studies report a complex, nonlinear relationship; large, intra-individual studies are lacking. Our objective was to analyze the TSH-free T4 relationship within individuals. We analyzed data from 13 379 patients, each with six or more TSH/free T4 measurements and at least a 5-fold difference between individual median TSH and minimum or maximum TSH. Linear and nonlinear regression models of log TSH on free T4 were fitted to data from individuals and goodness of fit compared by likelihood ratio testing. Comparing all models, the linear model achieved best fit in 31% of individuals, followed by quartic (27%), cubic (15%), null (12%), and quadratic (11%) models. After eliminating least favored models (with individuals reassigned to best fitting, available models), the linear model fit best in 42% of participants, quartic in 43%, and null model in 15%. As the number of observations per individual increased, so did the proportion of individuals in whom the linear model achieved best fit, to 66% in those with more than 20 observations. When linear models were applied to all individuals and averaged according to individual median free T4 values, variations in slope and intercept indicated a nonlinear log TSH-free T4 relationship across the population. The log TSH-free T4 relationship appears linear in some individuals and nonlinear in others, but is predominantly linear in those with the largest number of observations. A log-linear relationship within individuals can be reconciled with a non-log-linear relationship in a population.

Seasonal variation in the mating system of a selfing annual with large floral displays.

Science.gov (United States)

Yin, Ge; Barrett, Spencer C H; Luo, Yi-Bo; Bai, Wei-Ning

2016-03-01

Flowering plants display considerable variation in mating system, specifically the relative frequency of cross- and self-fertilization. The majority of estimates of outcrossing rate do not account for temporal variation, particularly during the flowering season. Here, we investigated seasonal variation in mating and fertility in Incarvillea sinensis (Bignoniaceae), an annual with showy, insect-pollinated, 'one-day' flowers capable of delayed selfing. We examined the influence of several biotic and abiotic environmental factors on day-to-day variation in fruit set, seed set and patterns of mating. We recorded daily flower number and pollinator abundance in nine 3 × 3-m patches in a population at Mu Us Sand land, Inner Mongolia, China. From marked flowers we collected data on daily fruit and seed set and estimated outcrossing rate and biparental inbreeding using six microsatellite loci and 172 open-pollinated families throughout the flowering period. Flower density increased significantly over most of the 50-d flowering season, but was associated with a decline in levels of pollinator service by bees, particularly on windy days. Fruit and seed set declined over time, especially during the latter third of the flowering period. Multilocus estimates of outcrossing rate were obtained using two methods (the programs MLTR and BORICE) and both indicated high selfing rates of ∼80 %. There was evidence for a significant increase in levels of selfing as the flowering season progressed and pollinator visitation declined. Biparental inbreeding also declined significantly as the flowering season progressed. Temporal variation in outcrossing rates may be a common feature of the mating biology of annual, insect-pollinated plants of harsh environments but our study is the first to examine seasonal mating-system dynamics in this context. Despite having large flowers and showy floral displays, I. sinensis attracted relatively few pollinators. Delayed selfing by corolla dragging

Inter-individual and inter-cell type variation in residual DNA damage after in vivo irradiation of human skin

International Nuclear Information System (INIS)

Chua, Melvin Lee Kiang; Somaiah, Navita; Bourne, Sara; Daley, Frances; A'Hern, Roger; Nuta, Otilia; Davies, Sue; Herskind, Carsten; Pearson, Ann; Warrington, Jim; Helyer, Sarah; Owen, Roger; Yarnold, John; Rothkamm, Kai

2011-01-01

Purpose: The aim of this study was to compare inter-individual and inter-cell type variation in DNA double-strand break (DSB) repair following in vivo irradiation of human skin. Materials and methods: Duplicate 4 mm core biopsies of irradiated and unirradiated skin were collected from 35 patients 24 h after 4 Gy exposure using 6 MeV electrons. Residual DSB were quantified by scoring 53BP1 foci in dermal fibroblasts, endothelial cells, superficial keratinocytes and basal epidermal cells. Results: Coefficients of inter-individual variation for levels of residual foci 24 h after in vivo irradiation of skin were 39.9% in dermal fibroblasts, 44.3% in endothelial cells, 32.9% in superficial keratinocytes and 46.4% in basal epidermal cells (p < 0.001, ANOVA). In contrast, the coefficient of inter-cell type variation for residual foci levels was only 11.3% in human skin between the different epidermal and dermal cells (p = 0.034, ANOVA). Foci levels between the different skin cell types were correlated (Pearson's R = 0.855-0.955, p < 0.001). Conclusions: Patient-specific factors appear to be more important than cell type-specific factors in determining residual foci levels following in vivo irradiation of human skin.

Individual variation in p53 and Cip1 expression profiles in normal human fibroblast strains following exposure to high-let radiation

Energy Technology Data Exchange (ETDEWEB)

Carpenter, T.R.; Johnson, N.F.; Gilliland, F.D. [Univ. of New Mexico, Albuquerque, NM (United States)] [and others

1995-12-01

Exposure to {alpha}-particles emitted by radon progeny appears to be the second-leading cause of lung cancer mortality. However, individual susceptibility to the carcinogenic effects of {alpha}-particles remains poorly characterized. Variation in susceptibility to cancer produced by certian classes of DNA-damaging chemicals is suspected to involve differences in metabolic activation and detoxication. Susceptibility to {alpha}-particle-induced cancer may involve variations in capacity or opportunity to repair DNA damage. Subtle variations in DNA repair capacity would more likely explain radon-related lung cancer susceptibility. The p53 tumor suppressor protein accumulates as a cellular response to DNA damage from ionizing radiation and regulates arrest in the G{sub 1} portion of the cell cycle. Arrest in G{sub 1} portion of the cell cycle. While upstream regulation of p53 protein stability is poorly understood, variations in the ability to accumulate p53 following DNA damage represent potential variations in lung cancer susceptibility related to radon progeny. Further, transcription of the cell-cycle regulatory gene Cip1 is regulated by p53 and increases following ionizing radiation. Therefore, variations in the expression of Cip1 following {alpha}-particle exposure may also be a susceptibility factor in radon-related lung cancers. The purpose of the present investigation was to measure p53 and Cip1 protein induction following {alpha}-particle exposure of fibroblast lines from nine individuals to determine if there were significant variations. The expression of Cip1 protein indicates the differences in response are biologically relevant.

Individual variation in p53 and Cip1 expression profiles in normal human fibroblast strains following exposure to high-let radiation

International Nuclear Information System (INIS)

Carpenter, T.R.; Johnson, N.F.; Gilliland, F.D.

1995-01-01

Exposure to α-particles emitted by radon progeny appears to be the second-leading cause of lung cancer mortality. However, individual susceptibility to the carcinogenic effects of α-particles remains poorly characterized. Variation in susceptibility to cancer produced by certian classes of DNA-damaging chemicals is suspected to involve differences in metabolic activation and detoxication. Susceptibility to α-particle-induced cancer may involve variations in capacity or opportunity to repair DNA damage. Subtle variations in DNA repair capacity would more likely explain radon-related lung cancer susceptibility. The p53 tumor suppressor protein accumulates as a cellular response to DNA damage from ionizing radiation and regulates arrest in the G 1 portion of the cell cycle. Arrest in G 1 portion of the cell cycle. While upstream regulation of p53 protein stability is poorly understood, variations in the ability to accumulate p53 following DNA damage represent potential variations in lung cancer susceptibility related to radon progeny. Further, transcription of the cell-cycle regulatory gene Cip1 is regulated by p53 and increases following ionizing radiation. Therefore, variations in the expression of Cip1 following α-particle exposure may also be a susceptibility factor in radon-related lung cancers. The purpose of the present investigation was to measure p53 and Cip1 protein induction following α-particle exposure of fibroblast lines from nine individuals to determine if there were significant variations. The expression of Cip1 protein indicates the differences in response are biologically relevant

Pluck or Luck: Does Trait Variation or Chance Drive Variation in Lifetime Reproductive Success?

Science.gov (United States)

Snyder, Robin E; Ellner, Stephen P

2018-04-01

While there has been extensive interest in how intraspecific trait variation affects ecological processes, outcomes are highly variable even when individuals are identical: some are lucky, while others are not. Trait variation is therefore important only if it adds substantially to the variability produced by luck. We ask when trait variation has a substantial effect on variability in lifetime reproductive success (LRS), using two approaches: (1) we partition the variation in LRS into contributions from luck and trait variation and (2) we ask what can be inferred about an individual's traits and with what certainty, given their observed LRS. In theoretical stage- and size-structured models and two empirical case studies, we find that luck usually dominates the variance of LRS. Even when individuals differ substantially in ways that affect expected LRS, unless the effects of luck are substantially reduced (e.g., low variability in reproductive life span or annual fecundity), most variance in lifetime outcomes is due to luck, implying that departures from "null" models omitting trait variation will be hard to detect. Luck also obscures the relationship between realized LRS and individual traits. While trait variation may influence the fate of populations, luck often governs the lives of individuals.

Large-scale geographical variation in eggshell metal and calcium content in a passerine bird (Ficedula hypoleuca).

Science.gov (United States)

Ruuskanen, Suvi; Laaksonen, Toni; Morales, Judith; Moreno, Juan; Mateo, Rafael; Belskii, Eugen; Bushuev, Andrey; Järvinen, Antero; Kerimov, Anvar; Krams, Indrikis; Morosinotto, Chiara; Mänd, Raivo; Orell, Markku; Qvarnström, Anna; Slate, Fred; Tilgar, Vallo; Visser, Marcel E; Winkel, Wolfgang; Zang, Herwig; Eeva, Tapio

2014-03-01

Birds have been used as bioindicators of pollution, such as toxic metals. Levels of pollutants in eggs are especially interesting, as developing birds are more sensitive to detrimental effects of pollutants than adults. Only very few studies have monitored intraspecific, large-scale variation in metal pollution across a species' breeding range. We studied large-scale geographic variation in metal levels in the eggs of a small passerine, the pied flycatcher (Ficedula hypoleuca), sampled from 15 populations across Europe. We measured 10 eggshell elements (As, Cd, Cr, Cu, Ni, Pb, Zn, Se, Sr, and Ca) and several shell characteristics (mass, thickness, porosity, and color). We found significant variation among populations in eggshell metal levels for all metals except copper. Eggshell lead, zinc, and chromium levels decreased from central Europe to the north, in line with the gradient in pollution levels over Europe, thus suggesting that eggshell can be used as an indicator of pollution levels. Eggshell lead levels were also correlated with soil lead levels and pH. Most of the metals were not correlated with eggshell characteristics, with the exception of shell mass, or with breeding success, which may suggest that birds can cope well with the current background exposure levels across Europe.

Small Tails Tell Tall Tales--Intra-Individual Variation in the Stable Isotope Values of Fish Fin.

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Brian Hayden

Full Text Available Fish fin is a widely used, non-lethal sample material in studies using stable isotopes to assess the ecology of fishes. However, fish fin is composed of two distinct tissues (ray and membrane which may have different stable isotope values and are not homogeneously distributed within a fin. As such, estimates of the stable isotope values of a fish may vary according to the section of fin sampled.To assess the magnitude of this variation, we analysed carbon (δ13C, nitrogen (δ15N, hydrogen (δ2H and oxygen (δ18O stable isotopes of caudal fin from juvenile, riverine stages of Atlantic salmon (Salmo salar and brown trout (Salmo trutta. Individual fins were sub-sectioned into tip, mid and base, of which a further subset were divided into ray and membrane.Isotope variation between fin sections, evident in all four elements, was primarily related to differences between ray and membrane. Base sections were13C depleted relative to tip (~1‰ with equivalent variation evident between ray and membrane. A similar trend was evident in δ2H, though the degree of variation was far greater (~10‰. Base and ray sections were 18O enriched (~2‰ relative to tip and membrane, respectively. Ray and membrane sections displayed longitudinal variation in 15N mirroring that of composite fin (~1‰, indicating that variation in15N values was likely related to ontogenetic variation.To account for the effects of intra-fin variability in stable isotope analyses we suggest that researchers sampling fish fin, in increasing priority, 1 also analyse muscle (or liver tissue from a subsample of fish to calibrate their data, or 2 standardize sampling by selecting tissue only from the extreme tip of a fin, or 3 homogenize fins prior to analysis.

Variation in Sensory Profile of Individual Rainbow Trout (Oncorhynchus mykiss) from the Same Production Batch

DEFF Research Database (Denmark)

Green-Petersen, Ditte; Hyldig, Grethe

2010-01-01

The variation in sensory profile of rainbow trout (Oncorhynchus mykiss), belonging to the same aquaculture production batch and handled the same way, was explored by using objective sensory profiling on heat-treated minced fillets. In addition, quality index, mechanical texture, pH, fat, and water...... content were measured. Different groups of fish were sampled 3 different times during a production day. The results showed significant differences in the sensory profiles of individual fish within all 3 groups as well as significant differences between the groups. Differences in mechanical texture were...... not explain the differences in the sensory profiling or in the mechanical texture measurements. The results showed that significant differences in the sensory profiles of individual fish from the same aquaculture production batch may occur. Furthermore, the results also showed sensory differences between...

Genetic architecture of natural variation in cuticular hydrocarbon composition in Drosophila melanogaster.

Science.gov (United States)

Dembeck, Lauren M; Böröczky, Katalin; Huang, Wen; Schal, Coby; Anholt, Robert R H; Mackay, Trudy F C

2015-11-14

Insect cuticular hydrocarbons (CHCs) prevent desiccation and serve as chemical signals that mediate social interactions. Drosophila melanogaster CHCs have been studied extensively, but the genetic basis for individual variation in CHC composition is largely unknown. We quantified variation in CHC profiles in the D. melanogaster Genetic Reference Panel (DGRP) and identified novel CHCs. We used principal component (PC) analysis to extract PCs that explain the majority of CHC variation and identified polymorphisms in or near 305 and 173 genes in females and males, respectively, associated with variation in these PCs. In addition, 17 DGRP lines contain the functional Desat2 allele characteristic of African and Caribbean D. melanogaster females (more 5,9-C27:2 and less 7,11-C27:2, female sex pheromone isomers). Disruption of expression of 24 candidate genes affected CHC composition in at least one sex. These genes are associated with fatty acid metabolism and represent mechanistic targets for individual variation in CHC composition.

Within- and between-individual variation in energy and nutrient intake in Japanese adults: effect of age and sex differences on group size and number of records required for adequate dietary assessment.

Science.gov (United States)

Fukumoto, Azusa; Asakura, Keiko; Murakami, Kentaro; Sasaki, Satoshi; Okubo, Hitomi; Hirota, Naoko; Notsu, Akiko; Todoriki, Hidemi; Miura, Ayako; Fukui, Mitsuru; Date, Chigusa

2013-01-01

Information on within- and between-individual variation in energy and nutrient intake is critical for precisely estimating usual dietary intake; however, data from Japanese populations are limited. We used dietary records to examine within- and between-individual variation by age and sex in the intake of energy and 31 selected nutrients among Japanese adults. We also calculated the group size required to estimate mean intake for a group and number of days required both to rank individuals within a group and to assess an individual's usual intake, all with appropriate arbitrary precision. A group of Japanese women (younger: 30-49 years, n = 58; older: 50-69 years, n = 63) and men (younger: 30-49 years, n = 54; older: 50-76 years, n = 67) completed dietary records for 4 nonconsecutive days in each season (16 days in total). Coefficients of within-individual variation and between-individual variation were generally larger in the younger group than in the older group and in men as compared with women. The group size required to estimate a group's mean intake, and number of days required to assess an individual's usual intake, were generally larger for the younger group and for men. In general, a longer period was required to rank women and older adults. In a group of Japanese adults, coefficients of within-individual variation and between-individual variation, which were used to estimate the group size and number of records required for adequate dietary assessment, differed by age, sex, and nutrient.

Temporal and spatial variations of travel-time residuals in central California for Novaya Zemlya events

International Nuclear Information System (INIS)

Robinson, R.; Iyer, H.M.

1976-01-01

Eight large nuclear explosions in Novaya Zemlya from October 1969 through November 1974 were used to monitor long-term variations in crustal seismic velocity near the San Andreas fault in central California. Relative P-wave travel-time residuals appear to be accurate to approximately +-0.1 sec. Of the over 100 stations used, none show clearly significant temporal variations in residual greater than this amount, corresponding to about a 4 percent change in velocity in the upper crust. Average relative residuals at individual stations show a large spatial variation of about 1.5 sec. These variations reflect both a complex crustal geology and changes in crustal thickness and provide a potentially powerful tool for studying crustal structure

Variation in Cognitive Failures: An Individual Differences Investigation of Everyday Attention and Memory Failures

Science.gov (United States)

Unsworth, Nash; Brewer, Gene A.; Spillers, Gregory J.

2012-01-01

The present study examined individual differences in everyday cognitive failures assessed by diaries. A large sample of participants completed various cognitive ability measures in the laboratory. Furthermore, a subset of these participants also recorded everyday cognitive failures (attention, retrospective memory, and prospective memory failures)…

Translating inter-individual genetic variation to biological function in complex phenotypes

DEFF Research Database (Denmark)

Yadav, Rachita

, Chapter 1 provides an introduction to various methodologies utilised in this thesis work. Subsequently, chapters 2, 3 and 4 in the second section, address finding causal variations in childhood asthma. Chapter 2 focuses on a genome wide association study (GWAS) performed on asthma exacerbation case cohort....... This study reports a new susceptibility locus within the gene CDHR3 for exacerbation phenotype of childhood asthma. Chapter 3 of the thesis presents a pilot study, which aims at designing a candidate gene panel for childhood asthma to identify the causal variants from known asthma genes. Chapter 4 describes...... in adipose depots, which is a major tissue implicated in obesity. Chapter 5 sheds light on different mechanisms that result in the replacement of metabolism efficient brown fat with the storage-type white fat in large mammals (including human) especially within the first few months following birth...

Random matrix approach to the dynamics of stock inventory variations

International Nuclear Information System (INIS)

Zhou Weixing; Mu Guohua; Kertész, János

2012-01-01

It is well accepted that investors can be classified into groups owing to distinct trading strategies, which forms the basic assumption of many agent-based models for financial markets when agents are not zero-intelligent. However, empirical tests of these assumptions are still very rare due to the lack of order flow data. Here we adopt the order flow data of Chinese stocks to tackle this problem by investigating the dynamics of inventory variations for individual and institutional investors that contain rich information about the trading behavior of investors and have a crucial influence on price fluctuations. We find that the distributions of cross-correlation coefficient C ij have power-law forms in the bulk that are followed by exponential tails, and there are more positive coefficients than negative ones. In addition, it is more likely that two individuals or two institutions have a stronger inventory variation correlation than one individual and one institution. We find that the largest and the second largest eigenvalues (λ 1 and λ 2 ) of the correlation matrix cannot be explained by random matrix theory and the projections of investors' inventory variations on the first eigenvector u(λ 1 ) are linearly correlated with stock returns, where individual investors play a dominating role. The investors are classified into three categories based on the cross-correlation coefficients C VR between inventory variations and stock returns. A strong Granger causality is unveiled from stock returns to inventory variations, which means that a large proportion of individuals hold the reversing trading strategy and a small part of individuals hold the trending strategy. Our empirical findings have scientific significance in the understanding of investors' trading behavior and in the construction of agent-based models for emerging stock markets. (paper)

Random matrix approach to the dynamics of stock inventory variations

Science.gov (United States)

Zhou, Wei-Xing; Mu, Guo-Hua; Kertész, János

2012-09-01

It is well accepted that investors can be classified into groups owing to distinct trading strategies, which forms the basic assumption of many agent-based models for financial markets when agents are not zero-intelligent. However, empirical tests of these assumptions are still very rare due to the lack of order flow data. Here we adopt the order flow data of Chinese stocks to tackle this problem by investigating the dynamics of inventory variations for individual and institutional investors that contain rich information about the trading behavior of investors and have a crucial influence on price fluctuations. We find that the distributions of cross-correlation coefficient Cij have power-law forms in the bulk that are followed by exponential tails, and there are more positive coefficients than negative ones. In addition, it is more likely that two individuals or two institutions have a stronger inventory variation correlation than one individual and one institution. We find that the largest and the second largest eigenvalues (λ1 and λ2) of the correlation matrix cannot be explained by random matrix theory and the projections of investors' inventory variations on the first eigenvector u(λ1) are linearly correlated with stock returns, where individual investors play a dominating role. The investors are classified into three categories based on the cross-correlation coefficients CV R between inventory variations and stock returns. A strong Granger causality is unveiled from stock returns to inventory variations, which means that a large proportion of individuals hold the reversing trading strategy and a small part of individuals hold the trending strategy. Our empirical findings have scientific significance in the understanding of investors' trading behavior and in the construction of agent-based models for emerging stock markets.

Collective Functionality through Bacterial Individuality

Science.gov (United States)

Ackermann, Martin

According to the conventional view, the properties of an organism are a product of nature and nurture - of its genes and the environment it lives in. Recent experiments with unicellular organisms have challenged this view: several molecular mechanisms generate phenotypic variation independently of environmental signals, leading to variation in clonal groups. My presentation will focus on the causes and consequences of this microbial individuality. Using examples from bacterial genetic model systems, I will first discuss different molecular and cellular mechanisms that give rise to bacterial individuality. Then, I will discuss the consequences of individuality, and focus on how phenotypic variation in clonal populations of bacteria can promote interactions between individuals, lead to the division of labor, and allow clonal groups of bacteria to cope with environmental uncertainty. Variation between individuals thus provides clonal groups with collective functionality.

Within- and between-culture variation: individual differences and the cultural logics of honor, face, and dignity cultures.

Science.gov (United States)

Leung, Angela K-Y; Cohen, Dov

2011-03-01

The CuPS (Culture × Person × Situation) approach attempts to jointly consider culture and individual differences, without treating either as noise and without reducing one to the other. Culture is important because it helps define psychological situations and create meaningful clusters of behavior according to particular logics. Individual differences are important because individuals vary in the extent to which they endorse or reject a culture's ideals. Further, because different cultures are organized by different logics, individual differences mean something different in each. Central to these studies are concepts of honor-related violence and individual worth as being inalienable versus socially conferred. We illustrate our argument with 2 experiments involving participants from honor, face, and dignity cultures. The studies showed that the same "type" of person who was most helpful, honest, and likely to behave with integrity in one culture was the "type" of person least likely to do so in another culture. We discuss how CuPS can provide a rudimentary but integrated approach to understanding both within- and between-culture variation. (c) 2011 APA, all rights reserved

Variation in human recombination rates and its genetic determinants.

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Adi Fledel-Alon

Full Text Available Despite the fundamental role of crossing-over in the pairing and segregation of chromosomes during human meiosis, the rates and placements of events vary markedly among individuals. Characterizing this variation and identifying its determinants are essential steps in our understanding of the human recombination process and its evolution.Using three large sets of European-American pedigrees, we examined variation in five recombination phenotypes that capture distinct aspects of crossing-over patterns. We found that the mean recombination rate in males and females and the historical hotspot usage are significantly heritable and are uncorrelated with one another. We then conducted a genome-wide association study in order to identify loci that influence them. We replicated associations of RNF212 with the mean rate in males and in females as well as the association of Inversion 17q21.31 with the female mean rate. We also replicated the association of PRDM9 with historical hotspot usage, finding that it explains most of the genetic variance in this phenotype. In addition, we identified a set of new candidate regions for further validation.These findings suggest that variation at broad and fine scales is largely separable and that, beyond three known loci, there is no evidence for common variation with large effects on recombination phenotypes.

Spinal cord compression caused by anaplastic large cell lymphoma in an HIV infected individual

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Kumar Susheel

2010-01-01

Full Text Available Lymphomas occur with an increased frequency in patients with Human Immunodeficiency Virus (HIV infection. These are usually high-grade immunoblastic lymphomas and primary central nervous system lymphomas. Anaplastic large cell lymphoma (ALCL is a distinct type of non-Hodgkin′s lymphoma. It is uncommon in HIV infected individuals. We describe here an uncommon presentation of this relatively rare lymphoma in the form of spinal cord compression syndrome in a young HIV infected individual.

Effects of uncertainty in model predictions of individual tree volume on large area volume estimates

Science.gov (United States)

Ronald E. McRoberts; James A. Westfall

2014-01-01

Forest inventory estimates of tree volume for large areas are typically calculated by adding model predictions of volumes for individual trees. However, the uncertainty in the model predictions is generally ignored with the result that the precision of the large area volume estimates is overestimated. The primary study objective was to estimate the effects of model...

Model-based diagnosis of large diesel engines based on angular speed variations of the crankshaft

Science.gov (United States)

Desbazeille, M.; Randall, R. B.; Guillet, F.; El Badaoui, M.; Hoisnard, C.

2010-07-01

This work aims at monitoring large diesel engines by analyzing the crankshaft angular speed variations. It focuses on a powerful 20-cylinder diesel engine with crankshaft natural frequencies within the operating speed range. First, the angular speed variations are modeled at the crankshaft free end. This includes modeling both the crankshaft dynamical behavior and the excitation torques. As the engine is very large, the first crankshaft torsional modes are in the low frequency range. A model with the assumption of a flexible crankshaft is required. The excitation torques depend on the in-cylinder pressure curve. The latter is modeled with a phenomenological model. Mechanical and combustion parameters of the model are optimized with the help of actual data. Then, an automated diagnosis based on an artificially intelligent system is proposed. Neural networks are used for pattern recognition of the angular speed waveforms in normal and faulty conditions. Reference patterns required in the training phase are computed with the model, calibrated using a small number of actual measurements. Promising results are obtained. An experimental fuel leakage fault is successfully diagnosed, including detection and localization of the faulty cylinder, as well as the approximation of the fault severity.

Individual variation in resisting temptation: implications for addiction

Science.gov (United States)

Saunders, Benjamin T.; Robinson, Terry E.

2013-01-01

When exposed to the sights, sounds, smells and/or places that have been associated with rewards, such as food or drugs, some individuals have difficulty resisting the temptation to seek out and consume them. Others have less difficulty restraining themselves. Thus, Pavlovian reward cues may motivate maladaptive patterns of behavior to a greater extent in some individuals than in others. We are just beginning to understand the factors underlying individual differences in the extent to which reward cues acquire powerful motivational properties, and therefore, the ability to act as incentive stimuli. Here we review converging evidence from studies in both human and non-human animals suggesting that a subset of individuals are more “cue reactive”, in that certain reward cues are more likely to attract these individuals to them and motivate actions to get them. We suggest that those individuals for whom Pavlovian reward cues become especially powerful incentives may be more vulnerable to impulse control disorders, such as binge eating and addiction. PMID:23438893

Individual co-variation between viral RNA load and gene expression reveals novel host factors during early dengue virus infection of the Aedes aegypti midgut.

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Vincent Raquin

2017-12-01

Full Text Available Dengue virus (DENV causes more human infections than any other mosquito-borne virus. The current lack of antiviral strategies has prompted genome-wide screens for host genes that are required for DENV infectivity. Earlier transcriptomic studies that identified DENV host factors in the primary vector Aedes aegypti used inbred laboratory colonies and/or pools of mosquitoes that erase individual variation. Here, we performed transcriptome sequencing on individual midguts in a field-derived Ae. aegypti population to identify new candidate host factors modulating DENV replication. We analyzed the transcriptomic data using an approach that accounts for individual co-variation between viral RNA load and gene expression. This approach generates a prediction about the agonist or antagonist effect of candidate genes on DENV replication based on the sign of the correlation between gene expression and viral RNA load. Using this method, we identified 39 candidate genes that went undetected by conventional pairwise comparison of gene expression levels between DENV-infected midguts and uninfected controls. Only four candidate genes were detected by both methods, emphasizing their complementarity. We demonstrated the value of our approach by functional validation of a candidate agonist gene encoding a sterol regulatory element-binding protein (SREBP, which was identified by correlation analysis but not by pairwise comparison. We confirmed that SREBP promotes DENV infection in the midgut by RNAi-mediated gene knockdown in vivo. We suggest that our approach for transcriptomic analysis can empower genome-wide screens for potential agonist or antagonist factors by leveraging inter-individual variation in gene expression. More generally, this method is applicable to a wide range of phenotypic traits displaying inter-individual variation.

The origin of the lower fourth molar in canids, inferred by individual variation

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Masakazu Asahara

2016-11-01

Full Text Available Background An increase in tooth number is an exception during mammalian evolution. The acquisition of the lower fourth molar in the bat-eared fox (Otocyon megalotis, Canidae, Carnivora, Mammalia is one example; however, its developmental origin is not clear. In some canids (Canidae, individual variation exist as supernumerary molar M4. This study focuses on the acquisition of the lower fourth molar in canids and proposes that the inhibitory cascade model can explain its origin. Methods Occlusal view projected area of lower molars was determined from 740 mandibles obtained from Canis latrans, Nyctereutes procyonoides, and Urocyon cinereoargenteus museum specimens. For each molar, relative sizes of molars (M2/M1 and M3/M1 scores affected by inhibition/activation dynamics during development, were compared between individuals with and without supernumerary molar (M4. Results Possession of a supernumerary molar was associated with significantly larger M2/M1 score in Canis latrans, M3/M1 score in Nyctereutes procyonoides, and M2/M1 and M3/M1 scores in Urocyon cinereoargenteus compared to individuals of these species that lacked supernumerary molars. Discussion We propose that, in canids, the supernumerary fourth molar is attributable to reduced inhibition and greater activation during molar development. In the bat-eared fox, altered inhibition and activation dynamics of dental development during omnivorous-insectivorous adaptation may be a contributing factor in the origin of the lower fourth molar.

Large-scale geographical variation in eggshell heavy metal and calcium content in a passerine bird (Ficedula hypoleuca)

NARCIS (Netherlands)

Ruuskanen, S.; Morales, J.; Laaksonen, T.; Moreno, J.; Mateo, R.; Belskii, E.; Bushuev, A.; Jarvinen, A.; Kerimov, A.; Krams, I.; Morosinotto, C.; Mand, R.; Orell, M.; Qvarnstrom, A.; Slater, F.M.; Siitari, H.; Tilgar, V.; Visser, M.E.; Winkel, W.; Zang, H.; Eeva, T.

2014-01-01

Birds have been used as bioindicators of pollution, such as toxic metals. Levels of pollutants in eggs are especially interesting, as developing birds are more sensitive to detrimental effects of pollutants than adults. Only very few studies have monitored intraspecific, large-scale variation in

Individual variation in resisting temptation: implications for addiction.

Science.gov (United States)

Saunders, Benjamin T; Robinson, Terry E

2013-11-01

When exposed to the sights, sounds, smells and/or places that have been associated with rewards, such as food or drugs, some individuals have difficulty resisting the temptation to seek out and consume them. Others have less difficulty restraining themselves. Thus, Pavlovian reward cues may motivate maladaptive patterns of behavior to a greater extent in some individuals than in others. We are just beginning to understand the factors underlying individual differences in the extent to which reward cues acquire powerful motivational properties, and therefore, the ability to act as incentive stimuli. Here we review converging evidence from studies in both human and non-human animals suggesting that a subset of individuals are more "cue reactive", in that certain reward cues are more likely to attract these individuals to them and motivate actions to get them. We suggest that those individuals for whom Pavlovian reward cues become especially powerful incentives may be more vulnerable to impulse control disorders, such as binge eating and addiction. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genetic Variation in Cardiomyopathy and Cardiovascular Disorders.

Science.gov (United States)

McNally, Elizabeth M; Puckelwartz, Megan J

2015-01-01

With the wider deployment of massively-parallel, next-generation sequencing, it is now possible to survey human genome data for research and clinical purposes. The reduced cost of producing short-read sequencing has now shifted the burden to data analysis. Analysis of genome sequencing remains challenged by the complexity of the human genome, including redundancy and the repetitive nature of genome elements and the large amount of variation in individual genomes. Public databases of human genome sequences greatly facilitate interpretation of common and rare genetic variation, although linking database sequence information to detailed clinical information is limited by privacy and practical issues. Genetic variation is a rich source of knowledge for cardiovascular disease because many, if not all, cardiovascular disorders are highly heritable. The role of rare genetic variation in predicting risk and complications of cardiovascular diseases has been well established for hypertrophic and dilated cardiomyopathy, where the number of genes that are linked to these disorders is growing. Bolstered by family data, where genetic variants segregate with disease, rare variation can be linked to specific genetic variation that offers profound diagnostic information. Understanding genetic variation in cardiomyopathy is likely to help stratify forms of heart failure and guide therapy. Ultimately, genetic variation may be amenable to gene correction and gene editing strategies.

Variation in heterozygosity predicts variation in human substitution rates between populations, individuals and genomic regions.

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William Amos

Full Text Available The "heterozygote instability" (HI hypothesis suggests that gene conversion events focused on heterozygous sites during meiosis locally increase the mutation rate, but this hypothesis remains largely untested. As humans left Africa they lost variability, which, if HI operates, should have reduced the mutation rate in non-Africans. Relative substitution rates were quantified in diverse humans using aligned whole genome sequences from the 1,000 genomes project. Substitution rate is consistently greater in Africans than in non-Africans, but only in diploid regions of the genome, consistent with a role for heterozygosity. Analysing the same data partitioned into a series of non-overlapping 2 Mb windows reveals a strong, non-linear correlation between the amount of heterozygosity lost "out of Africa" and the difference in substitution rate between Africans and non-Africans. Putative recent mutations, derived variants that occur only once among the 80 human chromosomes sampled, occur preferentially at the centre of 2 Kb windows that have elevated heterozygosity compared both with the same region in a closely related population and with an immediately adjacent region in the same population. More than half of all substitutions appear attributable to variation in heterozygosity. This observation provides strong support for HI with implications for many branches of evolutionary biology.

Family relationship of female breeders reduce the systematic inter-individual variation in the gut microbiota of inbred laboratory mice

DEFF Research Database (Denmark)

Hufeldt, Majbritt Ravn; Nielsen, Dennis Sandris; Vogensen, Finn Kvist

2010-01-01

The gut microbiota (GM) may influence disease expression in several animal models for inflammatory diseases. It may therefore seem reasonable to pursue reduction in the number of animals used for individual studies by reducing the variation in the GM. Previous studies have shown that the composit...... the family relatedness of the breeding pairs....

Among-Individual Variation in Desert Iguanas (Squamata: Dipsosaurus dorsalis): Endurance Capacity Is Positively Related to Home Range Size.

Science.gov (United States)

Singleton, Jennifer M; Garland, Theodore

Among species of lizards, endurance capacity measured on a motorized treadmill is positively related to daily movement distance and time spent moving, but few studies have addressed such relationships at the level of individual variation within a sex and age category in a single population. Both endurance capacity and home range size show substantial individual variation in lizards, rendering them suitable for such studies. We predicted that these traits would be positively related because endurance capacity is one of the factors that has the potential to limit home range size. We measured the endurance capacity and home range size of adult male desert iguanas (Dipsosaurus dorsalis). Lizards were field captured for measurements of endurance, and home range data were gathered using visual identification of previously marked individuals. Endurance was significantly repeatable between replicate trials, conducted 1-17 d apart ([Formula: see text] for log-transformed values, [Formula: see text], [Formula: see text]). The log of the higher of two endurance trials was positively but not significantly related to log body mass. The log of home range area was positively but not significantly related to log body mass, the number of sightings, or the time span from first to last sighting. As predicted, log endurance was positively correlated with log home range area ([Formula: see text], [Formula: see text], one-tailed [Formula: see text]; for body-mass residual endurance values: [Formula: see text], one-tailed [Formula: see text]). These results suggest that endurance capacity may have a permissive effect on home range size. Alternatively, individuals with larger home ranges may experience training effects (phenotypic plasticity) that increase their endurance.

Inter-individual variation among young children growing up in a bidialectal community : the acquisition of dialect and standard Dutch vocabulary.

NARCIS (Netherlands)

Francot, Ryanne; van den Heuij, Kirsten; Blom, Elma; Heeringa, W.J.; Cornips, L.M.E.A.; Buchstaller, Isabella; Siebenhaar, Beat

2017-01-01

This study focuses on the relationship between dialect use and the acquisition of standard Dutch vocabulary by young children in the Dutch province of Limburg. The results of a newly-developed dialect expressive vocabulary task show extensive inter-individual variation that does not support a

The intertidal community in West Greenland: Large-scale patterns and small-scale variation on ecosystem dynamics along a climate gradient

DEFF Research Database (Denmark)

Thyrring, Jakob; Blicher, Martin; Sejr, Mikael Kristian

are largely unknown. The West Greenland coast is north - south orientated. This provides an ideal setting to study the impact of climate change on marine species population dynamics and distribution. We investigated the latitudinal changes in the rocky intertidal community along 18° latitudes (59-77°N......) in West Greenland. Using cleared quadrats we quantified patterns in abundance, biomass and species richness in the intertidal zone. We use this data to disentangle patterns in Arctic intertidal communities at different scales. We describe the effects of different environmental drivers and species...... interactions on distribution and dynamics of intertidal species. Our results indicate that changes in distribution and abundance of foundation species can have large effects on the ecosystem. We also show that the importance of small-scale variation may be of same magnitude as large- scale variation. Only...

Multi-state models for clustered duration data: an application to workplace effects on individual sickness absenteeism

OpenAIRE

Lindeboom, Maarten; Kerkhofs, Marcel

1998-01-01

In this paper we specify and estimate three state duration models of work, sickness and exit from the job to explain individual absenteeism behaviour of primary school teachers. There is a large variation of sickness absenteeism records across schools and absenteeism records of workers within a school appear to be related. This clustering of individual absenteeism data may to a large extend be caused by workplace effects. Since it will be difficult to fully capture workplace effects with obse...

Variation in gene expression within clones of the earthworm Dendrobaena octaedra.

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Marina Mustonen

Full Text Available Gene expression is highly plastic, which can help organisms to both acclimate and adapt to changing environments. Possible variation in gene expression among individuals with the same genotype (among clones is not widely considered, even though it could impact the results of studies that focus on gene expression phenotypes, for example studies using clonal lines. We examined the extent of within and between clone variation in gene expression in the earthworm Dendrobaena octaedra, which reproduces through apomictic parthenogenesis. Five microsatellite markers were developed and used to confirm that offspring are genetic clones of their parent. After that, expression of 12 genes was measured from five individuals each from six clonal lines after exposure to copper contaminated soil. Variation in gene expression was higher over all genotypes than within genotypes, as initially assumed. A subset of the genes was also examined in the offspring of exposed individuals in two of the clonal lines. In this case, variation in gene expression within genotypes was as high as that observed over all genotypes. One gene in particular (chymotrypsin inhibitor also showed significant differences in the expression levels among genetically identical individuals. Gene expression can vary considerably, and the extent of variation may depend on the genotypes and genes studied. Ensuring a large sample, with many different genotypes, is critical in studies comparing gene expression phenotypes. Researchers should be especially cautious inferring gene expression phenotypes when using only a single clonal or inbred line, since the results might be specific to only certain genotypes.

Variation in Primary Cesarean Delivery Rates by Individual Physician within a Single Hospital Laborist Model

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METZ, Torri D.; ALLSHOUSE, Amanda A.; GILBERT, Sara A Babcock; DOYLE, Reina; TONG, Angie; CAREY, J. Christopher

2016-01-01

Background Laborist practice models are associated with lower cesarean delivery rates than individual private practice models in several studies; however, this effect is not uniform. Further exploration of laborist models may help us better understand the observed reduction in cesarean delivery rates in some hospitals with implementation of a laborist model. Objective Our objective was to evaluate the degree of variation in primary cesarean delivery rates by individual laborists within a single institution employing a laborist model. In addition, we sought to evaluate whether differences in cesarean delivery rates resulted in different maternal or short-term neonatal outcomes. Study Design At this teaching institution, one laborist (either a generalist or maternal-fetal medicine attending physician) is directly responsible for labor and delivery management during each shift. No patients are followed in a private practice model nor are physicians incentivized to perform deliveries. We retrospectively identified all laborists who delivered nulliparous, term women with cephalic singletons at this institution from 2007-14. Overall and individual primary cesarean delivery rates were reported as percentages with exact Pearson 95% CI. Laborists were grouped by tertile as having low, medium or high cesarean delivery rates. Characteristics of the women delivered, indications for cesarean delivery, and short-term neonatal outcomes were compared between these groups. A binomial regression model of cesarean delivery was estimated, where the relative rates of each laborist compared to the lowest-unadjusted laborist rate were calculated; a second model was estimated to adjust for patient-level maternal characteristics. Results Twenty laborists delivered 2,224 nulliparous, term women with cephalic singletons. The overall cesarean delivery rate was 24.1% (95% CI 21.4-26.8). In an unadjusted binomial model, the overall effect of individual laborist was significant (pcesarean

Individual killer whale vocal variation during intra-group behavioral dynamics

Science.gov (United States)

Grebner, Dawn M.

The scientific goal of this dissertation was to carefully study the signal structure of killer whale communications and vocal complexity and link them to behavioral circumstances. The overall objective of this research sought to provide insight into killer whale call content and usage which may be conveying information to conspecifics in order to maintain group cohesion. Data were collected in the summers of 2006 and 2007 in Johnstone Strait, British Columbia. For both individuals and small groups, vocalizations were isolated using a triangular hydrophone array and the behavioral movement patterns were captured by a theodolite and video camera positioned on a cliff overlooking the hyrophone locations. This dissertation is divided into four analysis chapters. In Chapter 3, discriminant analysis was used to validate the four N04 call subtypes which were originally parsed due to variations in slope segments. The first two functions of the discriminant analysis explained 97% of the variability. Most of the variability for the N04 call was found in the front convex and the terminal portions of the call, while very little variability was found in the center region of the call. This research revealed that individual killer whales produced multiple subtypes of the N04 call. No correlations of behaviors to acoustic parameters obtained were found. The aim of the Chapter 4 was to determine if killer whale calling behavior varied prior to and after the animals had joined. Pulsed call rates were found to be greater pre- compared to post-joining events. Two-way vocal exchanges were more common occurring 74% of the time during pre-joining events. In Chapter 5, initiated and first response to calls varied between age/sex class groups when mothers were separated from an offspring. Solo mothers and calves initiated pulsed calls more often than they responded. Most of the no vocal responses were due to mothers who were foraging. Finally, observations of the frequency split in N04

A large-scale survey of genetic copy number variations among Han Chinese residing in Taiwan

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Wu Jer-Yuarn

2008-12-01

Full Text Available Abstract Background Copy number variations (CNVs have recently been recognized as important structural variations in the human genome. CNVs can affect gene expression and thus may contribute to phenotypic differences. The copy number inferring tool (CNIT is an effective hidden Markov model-based algorithm for estimating allele-specific copy number and predicting chromosomal alterations from single nucleotide polymorphism microarrays. The CNIT algorithm, which was constructed using data from 270 HapMap multi-ethnic individuals, was applied to identify CNVs from 300 unrelated Han Chinese individuals in Taiwan. Results Using stringent selection criteria, 230 regions with variable copy numbers were identified in the Han Chinese population; 133 (57.83% had been reported previously, 64 displayed greater than 1% CNV allele frequency. The average size of the CNV regions was 322 kb (ranging from 1.48 kb to 5.68 Mb and covered a total of 2.47% of the human genome. A total of 196 of the CNV regions were simple deletions and 27 were simple amplifications. There were 449 genes and 5 microRNAs within these CNV regions; some of these genes are known to be associated with diseases. Conclusion The identified CNVs are characteristic of the Han Chinese population and should be considered when genetic studies are conducted. The CNV distribution in the human genome is still poorly characterized, and there is much diversity among different ethnic populations.

Individual Aesthetic Preferences for Faces Are Shaped Mostly by Environments, Not Genes.

Science.gov (United States)

Germine, Laura; Russell, Richard; Bronstad, P Matthew; Blokland, Gabriëlla A M; Smoller, Jordan W; Kwok, Holum; Anthony, Samuel E; Nakayama, Ken; Rhodes, Gillian; Wilmer, Jeremy B

2015-10-19

Although certain characteristics of human faces are broadly considered more attractive (e.g., symmetry, averageness), people also routinely disagree with each other on the relative attractiveness of faces. That is, to some significant degree, beauty is in the "eye of the beholder." Here, we investigate the origins of these individual differences in face preferences using a twin design, allowing us to estimate the relative contributions of genetic and environmental variation to individual face attractiveness judgments or face preferences. We first show that individual face preferences (IP) can be reliably measured and are readily dissociable from other types of attractiveness judgments (e.g., judgments of scenes, objects). Next, we show that individual face preferences result primarily from environments that are unique to each individual. This is in striking contrast to individual differences in face identity recognition, which result primarily from variations in genes [1]. We thus complete an etiological double dissociation between two core domains of social perception (judgments of identity versus attractiveness) within the same visual stimulus (the face). At the same time, we provide an example, rare in behavioral genetics, of a reliably and objectively measured behavioral characteristic where variations are shaped mostly by the environment. The large impact of experience on individual face preferences provides a novel window into the evolution and architecture of the social brain, while lending new empirical support to the long-standing claim that environments shape individual notions of what is attractive. Copyright © 2015 Elsevier Ltd. All rights reserved.

What I experienced yesterday is who I am today: relationship of work motivations and behaviors to within-individual variation in the five-factor model of personality.

Science.gov (United States)

Judge, Timothy A; Simon, Lauren S; Hurst, Charlice; Kelley, Ken

2014-03-01

Historically, organizational and personality psychologists have ignored within-individual variation in personality across situations or have treated it as measurement error. However, we conducted a 10-day experience sampling study consistent with whole trait theory (Fleeson, 2012), which conceptualizes personality as a system of stable tendencies and patterns of intraindividual variation along the dimensions of the Big Five personality traits (Costa & McCrae, 1992). The study examined whether (a) internal events (i.e., motivation), performance episodes, and interpersonal experiences at work predict deviations from central tendencies in trait-relevant behavior, affect, and cognition (i.e., state personality), and (b) there are individual differences in responsiveness to work experiences. Results revealed that personality at work exhibited both stability and variation within individuals. Trait measures predicted average levels of trait manifestation in daily behavior at work, whereas daily work experiences (i.e., organizational citizenship, interpersonal conflict, and motivation) predicted deviations from baseline tendencies. Additionally, correlations of neuroticism with standard deviations in the daily personality variables suggest that, although work experiences influence state personality, people higher in neuroticism exhibit higher levels of intraindividual variation in personality than do those who are more emotionally stable.

Unexpected Nongenetic Individual Heterogeneity and Trait Covariance in Daphnia and Its Consequences for Ecological and Evolutionary Dynamics.

Science.gov (United States)

Cressler, Clayton E; Bengtson, Stefan; Nelson, William A

2017-07-01

Individual differences in genetics, age, or environment can cause tremendous differences in individual life-history traits. This individual heterogeneity generates demographic heterogeneity at the population level, which is predicted to have a strong impact on both ecological and evolutionary dynamics. However, we know surprisingly little about the sources of individual heterogeneity for particular taxa or how different sources scale up to impact ecological and evolutionary dynamics. Here we experimentally study the individual heterogeneity that emerges from both genetic and nongenetic sources in a species of freshwater zooplankton across a large gradient of food quality. Despite the tight control of environment, we still find that the variation from nongenetic sources is greater than that from genetic sources over a wide range of food quality and that this variation has strong positive covariance between growth and reproduction. We evaluate the general consequences of genetic and nongenetic covariance for ecological and evolutionary dynamics theoretically and find that increasing nongenetic variation slows evolution independent of the correlation in heritable life-history traits but that the impact on ecological dynamics depends on both nongenetic and genetic covariance. Our results demonstrate that variation in the relative magnitude of nongenetic versus genetic sources of variation impacts the predicted ecological and evolutionary dynamics.

Patterns of variations in large pelagic fish: A comparative approach between the Indian and the Atlantic Oceans

Science.gov (United States)

Corbineau, A.; Rouyer, T.; Fromentin, J.-M.; Cazelles, B.; Fonteneau, A.; Ménard, F.

2010-07-01

Catch data of large pelagic fish such as tuna, swordfish and billfish are highly variable ranging from short to long term. Based on fisheries data, these time series are noisy and reflect mixed information on exploitation (targeting, strategy, fishing power), population dynamics (recruitment, growth, mortality, migration, etc.), and environmental forcing (local conditions or dominant climate patterns). In this work, we investigated patterns of variation of large pelagic fish (i.e. yellowfin tuna, bigeye tuna, swordfish and blue marlin) in Japanese longliners catch data from 1960 to 2004. We performed wavelet analyses on the yearly time series of each fish species in each biogeographic province of the tropical Indian and Atlantic Oceans. In addition, we carried out cross-wavelet analyses between these biological time series and a large-scale climatic index, i.e. the Southern Oscillation Index (SOI). Results showed that the biogeographic province was the most important factor structuring the patterns of variability of Japanese catch time series. Relationships between the SOI and the fish catches in the Indian and Atlantic Oceans also pointed out the role of climatic variability for structuring patterns of variation of catch time series. This work finally confirmed that Japanese longline CPUE data poorly reflect the underlying population dynamics of tunas.

Large earthquake rupture process variations on the Middle America megathrust

Science.gov (United States)

Ye, Lingling; Lay, Thorne; Kanamori, Hiroo

2013-11-01

The megathrust fault between the underthrusting Cocos plate and overriding Caribbean plate recently experienced three large ruptures: the August 27, 2012 (Mw 7.3) El Salvador; September 5, 2012 (Mw 7.6) Costa Rica; and November 7, 2012 (Mw 7.4) Guatemala earthquakes. All three events involve shallow-dipping thrust faulting on the plate boundary, but they had variable rupture processes. The El Salvador earthquake ruptured from about 4 to 20 km depth, with a relatively large centroid time of ˜19 s, low seismic moment-scaled energy release, and a depleted teleseismic short-period source spectrum similar to that of the September 2, 1992 (Mw 7.6) Nicaragua tsunami earthquake that ruptured the adjacent shallow portion of the plate boundary. The Costa Rica and Guatemala earthquakes had large slip in the depth range 15 to 30 km, and more typical teleseismic source spectra. Regional seismic recordings have higher short-period energy levels for the Costa Rica event relative to the El Salvador event, consistent with the teleseismic observations. A broadband regional waveform template correlation analysis is applied to categorize the focal mechanisms for larger aftershocks of the three events. Modeling of regional wave spectral ratios for clustered events with similar mechanisms indicates that interplate thrust events have corner frequencies, normalized by a reference model, that increase down-dip from anomalously low values near the Middle America trench. Relatively high corner frequencies are found for thrust events near Costa Rica; thus, variations along strike of the trench may also be important. Geodetic observations indicate trench-parallel motion of a forearc sliver extending from Costa Rica to Guatemala, and low seismic coupling on the megathrust has been inferred from a lack of boundary-perpendicular strain accumulation. The slip distributions and seismic radiation from the large regional thrust events indicate relatively strong seismic coupling near Nicoya, Costa

Feature discrimination/identification based upon SAR return variations

Science.gov (United States)

Rasco, W. A., Sr.; Pietsch, R.

1978-01-01

A study of the statistics of The look-to-look variation statistics in the returns recorded in-flight by a digital, realtime SAR system are analyzed. The determination that the variations in the look-to-look returns from different classes do carry information content unique to the classes was illustrated by a model based on four variants derived from four look in-flight SAR data under study. The model was limited to four classes of returns: mowed grass on a athletic field, rough unmowed grass and weeds on a large vacant field, young fruit trees in a large orchard, and metal mobile homes and storage buildings in a large mobile home park. The data population in excess of 1000 returns represented over 250 individual pixels from the four classes. The multivariant discriminant model operated on the set of returns for each pixel and assigned that pixel to one of the four classes, based on the target variants and the probability distribution function of the four variants for each class.

Does SGLT2 inhibition with dapagliflozin overcome individual therapy resistance to RAAS inhibition?

NARCIS (Netherlands)

Petrykiv, Sergei; Laverman, Gozewijn D.; de Zeeuw, Dick; Heerspink, Hiddo J. L.

Individual patients show a large variation in their response to renin-angiotensin-aldosteron system (RAAS) inhibition (RAASi), both in surrogates such as albuminuria and in hard renal outcomes. Sodium-glucose co-transporter 2 inhibitors (SGLT2) have been shown to lower albuminuria and to confer

Assessment of the magnitude of geographical variations in the duration of non-work-related sickness absence by individual and contextual factors

Directory of Open Access Journals (Sweden)

Isabel Torá-Rocamora

2015-05-01

Conclusions: County-level variation in the duration of NWRSA was small and was explained more by individual than by contextual variables. Knowledge of geographic differences in NWRSA duration is needed to plan specific programs and interventions to minimize these differences.

Long-Term Survival of Individuals Born Small and Large for Gestational Age.

Directory of Open Access Journals (Sweden)

E Christina M Wennerström

Full Text Available Little is known on long-term survival and causes of death among individuals born small or large for gestational age. This study investigates birth weight in relation to survival and causes of death over time.A national cohort of 1.7 million live-born singletons in Denmark was followed during 1979-2011, using the Danish Civil Registration System, the Medical Birth Registry and the Cause of Death Registry. Cox proportional hazards were estimated for the impact of small (SGA and large (LGA gestation weight and mortality overall, by age group and birth cohort.Compared to normal weight children, SGA children were associated with increased risk of dying over time. Though most of the deaths occurred during the first year of life, the cumulative mortality risk was increased until 30 years of age. The hazard ratios [HR] for dying among SGA children ages <2 years were: 3.47 (95% CI, 3.30-3.64 and 1.06 (95% CI, 0.60-1.87 in 30 years and older. HR for dying among SGA adults (20-29 years were: 1.20 (95% CI, 0.99-1.46 in years 1979-1982 and 1.61 (95% CI, 1.04-2.51 in years 1989-1994. The SGA born had increased risk of dying from infection, heart disease, respiratory disease, digestive disease, congenital malformation, perinatal conditions, and accidents, suicide, and homicide. Individuals born LGA were associated with decreased mortality risk, but with increased risk of dying from malignant neoplasm.Survival has improved independently of birth weight the past 30 years. However, children born SGA remain at significantly increased risk of dying up till they turn 30 years of age. Individuals born LGA have lower mortality risk but only in the first two years of life.

Noise genetics: inferring protein function by correlating phenotype with protein levels and localization in individual human cells.

Directory of Open Access Journals (Sweden)

Shlomit Farkash-Amar

2014-03-01

Full Text Available To understand gene function, genetic analysis uses large perturbations such as gene deletion, knockdown or over-expression. Large perturbations have drawbacks: they move the cell far from its normal working point, and can thus be masked by off-target effects or compensation by other genes. Here, we offer a complementary approach, called noise genetics. We use natural cell-cell variations in protein level and localization, and correlate them to the natural variations of the phenotype of the same cells. Observing these variations is made possible by recent advances in dynamic proteomics that allow measuring proteins over time in individual living cells. Using motility of human cancer cells as a model system, and time-lapse microscopy on 566 fluorescently tagged proteins, we found 74 candidate motility genes whose level or localization strongly correlate with motility in individual cells. We recovered 30 known motility genes, and validated several novel ones by mild knockdown experiments. Noise genetics can complement standard genetics for a variety of phenotypes.

Multistate models for clustered duration data - An application to workplace effects on individual sickness absenteeism

NARCIS (Netherlands)

Lindeboom, Maarten; Kerkhofs, Marcel

2000-01-01

Sickness absenteeism figures show a relatively large amount of variation across firms and organizations, indicating substantial within-firm correlations between absenteeism records of individual workers. To study the role of firm-specific circumstances and workforce composition, we specify

Individualization of treatments with drugs metabolized by CES1: combining genetics and metabolomics

DEFF Research Database (Denmark)

Rasmussen, Henrik B.; Bjerre, Ditte; Linnet, Kristian

2015-01-01

CES1 is involved in the hydrolysis of ester group-containing xenobiotic and endobiotic compounds including several essential and commonly used drugs. The individual variation in the efficacy and tolerability of many drugs metabolized by CES1 is considerable. Hence, there is a large interest in in...

Global Climate Forcing from Albedo Change Caused by Large-scale Deforestation and Reforestation: Quantification and Attribution of Geographic Variation

Science.gov (United States)

Jiao, Tong; Williams, Christopher A.; Ghimire, Bardan; Masek, Jeffrey; Gao, Feng; Schaaf, Crystal

2017-01-01

Large-scale deforestation and reforestation have contributed substantially to historical and contemporary global climate change in part through albedo-induced radiative forcing, with meaningful implications for forest management aiming to mitigate climate change. Associated warming or cooling varies widely across the globe due to a range of factors including forest type, snow cover, and insolation, but resulting geographic variation remain spoorly described and has been largely based on model assessments. This study provides an observation-based approach to quantify local and global radiative forcings from large-scale deforestation and reforestation and further examines mechanisms that result in the spatial heterogeneity of radiative forcing. We incorporate a new spatially and temporally explicit land cover-specific albedo product derived from Moderate Resolution Imaging Spectroradiometer with a historical land use data set (Land Use Harmonization product). Spatial variation in radiative forcing was attributed to four mechanisms, including the change in snow-covered albedo, change in snow-free albedo, snow cover fraction, and incoming solar radiation. We find an albedo-only radiative forcing (RF) of -0.819 W m(exp -2) if year 2000 forests were completely deforested and converted to croplands. Albedo RF from global reforestation of present-day croplands to recover year 1700 forests is estimated to be 0.161 W m)exp -2). Snow-cover fraction is identified as the primary factor in determining the spatial variation of radiative forcing in winter, while the magnitude of the change in snow-free albedo is the primary factor determining variations in summertime RF. Findings reinforce the notion that, for conifers at the snowier high latitudes, albedo RF diminishes the warming from forest loss and the cooling from forest gain more so than for other forest types, latitudes, and climate settings.

Genetic variation in adaptability and pleiotropy in budding yeast.

Science.gov (United States)

Jerison, Elizabeth R; Kryazhimskiy, Sergey; Mitchell, James Kameron; Bloom, Joshua S; Kruglyak, Leonid; Desai, Michael M

2017-08-17

Evolution can favor organisms that are more adaptable, provided that genetic variation in adaptability exists. Here, we quantify this variation among 230 offspring of a cross between diverged yeast strains. We measure the adaptability of each offspring genotype, defined as its average rate of adaptation in a specific environmental condition, and analyze the heritability, predictability, and genetic basis of this trait. We find that initial genotype strongly affects adaptability and can alter the genetic basis of future evolution. Initial genotype also affects the pleiotropic consequences of adaptation for fitness in a different environment. This genetic variation in adaptability and pleiotropy is largely determined by initial fitness, according to a rule of declining adaptability with increasing initial fitness, but several individual QTLs also have a significant idiosyncratic role. Our results demonstrate that both adaptability and pleiotropy are complex traits, with extensive heritable differences arising from naturally occurring variation.

Variations in levels of care between nursing home patients in a public health care system.

Science.gov (United States)

Døhl, Øystein; Garåsen, Helge; Kalseth, Jorid; Magnussen, Jon

2014-03-05

Within the setting of a public health service we analyse the distribution of resources between individuals in nursing homes funded by global budgets. Three questions are pursued. Firstly, whether there are systematic variations between nursing homes in the level of care given to patients. Secondly, whether such variations can be explained by nursing home characteristics. And thirdly, how individual need-related variables are associated with differences in the level of care given. The study included 1204 residents in 35 nursing homes and extra care sheltered housing facilities. Direct time spent with patients was recorded. In average each patient received 14.8 hours direct care each week. Multilevel regression analysis is used to analyse the relationship between individual characteristics, nursing home characteristics and time spent with patients in nursing homes. The study setting is the city of Trondheim, with a population of approximately 180 000. There are large variations between nursing homes in the total amount of individual care given to patients. As much as 24 percent of the variation of individual care between patients could be explained by variation between nursing homes. Adjusting for structural nursing home characteristics did not substantially reduce the variation between nursing homes. As expected a negative association was found between individual care and case-mix, implying that at nursing home level a more resource demanding case-mix is compensated by lowering the average amount of care. At individual level ADL-disability is the strongest predictor for use of resources in nursing homes. For the average user one point increase in ADL-disability increases the use of resources with 27 percent. In a financial reimbursement model for nursing homes with no adjustment for case-mix, the amount of care patients receive does not solely depend on the patients' own needs, but also on the needs of all the other residents.

Chinese L1 children's English L2 verb morphology over time: individual variation in long-term outcomes.

Science.gov (United States)

Paradis, Johanne; Tulpar, Yasemin; Arppe, Antti

2016-05-01

This study examined accuracy in production and grammaticality judgements of verb morphology by eighteen Chinese-speaking children learning English as a second language (L2) followed longitudinally from four to six years of exposure to English, and who began to learn English at age 4;2. Children's growth in accuracy with verb morphology reached a plateau by six years, where 11/18 children did not display native-speaker levels of accuracy for one or more morphemes. Variation in children's accuracy with verb morphology was predicted by their English vocabulary size and verbal short-term memories primarily, and quality and quantity of English input at home secondarily. This study shows that even very young L2 learners might not all catch up to native speakers in this time frame and that non-age factors play a role in determining individual variation in child L2 learners' long-term outcomes with English morphology.

Fission Product Release Behavior of Individual Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

International Nuclear Information System (INIS)

Minato, Kazuo; Sawa, Kazuhiro; Koya, Toshio; Tomita, Takeshi; Ishikawa, Akiyoshi; Baldwin, Charles A.; Gabbard, William Alexander; Malone, Charlie M.

2000-01-01

Postirradiation heating tests of TRISO-coated UO 2 particles at 1700 and 1800degC were performed to understand fission product release behavior at accident temperatures. The inventory measurements of the individual particles were carried out before and after the heating tests with gamma-ray spectrometry to study the behavior of the individual particles. The time-dependent release behavior of 85 Kr, 110m Ag, 134 Cs, 137 Cs, and 154 Eu were obtained with on-line measurements of fission gas release and intermittent measurements of metallic fission product release during the heating tests. The inventory measurements of the individual particles revealed that fission product release behavior of the individual particles was not uniform, and large particle-to-particle variations in the release behavior of 110m Ag, 134 Cs, 137 Cs, and 154 Eu were found. X-ray microradiography and ceramography showed that the variations could not be explained by only the presence or absence of cracks in the SiC coating layer. The SiC degradation may have been related to the variations

The African Genome Variation Project shapes medical genetics in Africa

Science.gov (United States)

Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.

2015-01-01

Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.

The African Genome Variation Project shapes medical genetics in Africa.

Science.gov (United States)

Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O; Choudhury, Ananyo; Ritchie, Graham R S; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N; Young, Elizabeth H; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S

2015-01-15

Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.

Differences and effects of medium and large adult cuffs on blood pressure readings in individuals with muscular arms.

Science.gov (United States)

Fonseca-Reyes, Salvador; Fajardo-Flores, Ismael; Montes-Casillas, Mayra; Forsyth-Macquarrie, Avril

2009-08-01

This study analyzed systolic and diastolic blood pressure (SBP and DBP) reading differences in individuals with muscular arms, using medium and large adult cuffs. Resting blood pressures (BPs) were measured in bodybuilders competing at the Mexican National Bodybuilding and Fitness Championship. The means of two bilateral simultaneous arm BP measurements were obtained using two different cuff sizes, 12 cm (medium adult) and 16 cm (large adult). A total of 193 bodybuilders completed the measurements. With an arm circumference greater than 33 cm, the SBP and DBP average taken with the medium adult cuff was higher than that obtained with the large adult cuff, 8.2+/-10.6 and 1.6+/-7.4 mmHg, respectively; however, a significant difference was observed only with the SBP. With the medium adult cuff, 48 of 144 individuals showed SBP at least 140 mmHg, whereas with the large adult cuff there were only 17 of 144 individuals. In those participants with an arm circumference less than 33 cm, the BP was nonsignificantly lower with the large cuff, -4.24+/-9.2 and -2.24+/-5.4 mmHg for the SBP and DBP, respectively. Incorrect cuffing of a muscular arm leads to significant errors in the measurement of SBP and DBP, similar to that observed in miscuffing of nonmuscular arms.

Inter individual variations of the fish skin microbiota: host genetics basis of mutualism?

Science.gov (United States)

Boutin, Sébastien; Sauvage, Christopher; Bernatchez, Louis; Audet, Céline; Derome, Nicolas

2014-01-01

The commensal microbiota of fish skin is suspected to provide a protection against opportunist infections. The skin of fish harbors a complex and diverse microbiota that closely interacts with the surrounding water microbial communities. Up to now there is no clear evidence as to whether the host regulates the recruitment of environmental bacteria to build a specific skin microbiota. To address this question, we detected Quantitative Trait Loci (QTL) associated with the abundance of specific skin microbiota bacterial strains in brook charr (Salvelinus fontinalis), combining 16S RNA tagged-amplicon 454 pyrosequencing with genetic linkage analysis. Skin microbiota analysis revealed high inter-individual variation among 86 F2 fish progeny based upon the relative abundance of bacterial operational taxonomic units (OTUs). Out of those OTUs, the pathogenic strain Flavobacterium psychrophilum and the non-pathogenic strain Methylobacterium rhodesianum explained the majority of inter-individual distances. Furthermore, a strong negative correlation was found between Flavobacterium and Methylobacterium, suggesting a mutually competitive relationship. Finally, after considering a total of 266 markers, genetic linkage analysis highlighted three major QTL associated with the abundance of Lysobacter, Rheinheimera and Methylobacterium. All these three genera are known for their beneficial antibacterial activity. Overall, our results provide evidence that host genotype may regulate the abundance of specific genera among their surface microbiota. They also indicate that Lysobacter, Rheinheimera and Methylobacterium are potentially important genera in providing protection against pathogens.

Humans and Deep Networks Largely Agree on Which Kinds of Variation Make Object Recognition Harder.

Science.gov (United States)

Kheradpisheh, Saeed R; Ghodrati, Masoud; Ganjtabesh, Mohammad; Masquelier, Timothée

2016-01-01

View-invariant object recognition is a challenging problem that has attracted much attention among the psychology, neuroscience, and computer vision communities. Humans are notoriously good at it, even if some variations are presumably more difficult to handle than others (e.g., 3D rotations). Humans are thought to solve the problem through hierarchical processing along the ventral stream, which progressively extracts more and more invariant visual features. This feed-forward architecture has inspired a new generation of bio-inspired computer vision systems called deep convolutional neural networks (DCNN), which are currently the best models for object recognition in natural images. Here, for the first time, we systematically compared human feed-forward vision and DCNNs at view-invariant object recognition task using the same set of images and controlling the kinds of transformation (position, scale, rotation in plane, and rotation in depth) as well as their magnitude, which we call "variation level." We used four object categories: car, ship, motorcycle, and animal. In total, 89 human subjects participated in 10 experiments in which they had to discriminate between two or four categories after rapid presentation with backward masking. We also tested two recent DCNNs (proposed respectively by Hinton's group and Zisserman's group) on the same tasks. We found that humans and DCNNs largely agreed on the relative difficulties of each kind of variation: rotation in depth is by far the hardest transformation to handle, followed by scale, then rotation in plane, and finally position (much easier). This suggests that DCNNs would be reasonable models of human feed-forward vision. In addition, our results show that the variation levels in rotation in depth and scale strongly modulate both humans' and DCNNs' recognition performances. We thus argue that these variations should be controlled in the image datasets used in vision research.

Humans and deep networks largely agree on which kinds of variation make object recognition harder

Directory of Open Access Journals (Sweden)

Saeed Reza Kheradpisheh

2016-08-01

Full Text Available View-invariant object recognition is a challenging problem that has attracted much attention among the psychology, neuroscience, and computer vision communities. Humans are notoriously good at it, even if some variations are presumably more difficult to handle than others (e.g. 3D rotations. Humans are thought to solve the problem through hierarchical processing along the ventral stream, which progressively extracts more and more invariant visual features. This feed-forward architecture has inspired a new generation of bio-inspired computer vision systems called deep convolutional neural networks (DCNN, which are currently the best models for object recognition in natural images. Here, for the first time, we systematically compared human feed-forward vision and DCNNs at view-invariant object recognition task using the same set of images and controlling the kinds of transformation (position, scale, rotation in plane, and rotation in depth as well as their magnitude, which we call variation level. We used four object categories: car, ship, motorcycle, and animal. In total, 89 human subjects participated in 10 experiments in which they had to discriminate between two or four categories after rapid presentation with backward masking. We also tested two recent DCNNs (proposed respectively by Hinton's group and Zisserman's group on the same tasks. We found that humans and DCNNs largely agreed on the relative difficulties of each kind of variation: rotation in depth is by far the hardest transformation to handle, followed by scale, then rotation in plane, and finally position (much easier. This suggests that DCNNs would be reasonable models of human feed-forward vision. In addition, our results show that the variation levels in rotation in depth and scale strongly modulate both humans' and DCNNs' recognition performances. We thus argue that these variations should be controlled in the image datasets used in vision research.

Linking neurogenetics and individual differences in language learning: the dopamine hypothesis.

Science.gov (United States)

Wong, Patrick C M; Morgan-Short, Kara; Ettlinger, Marc; Zheng, Jing

2012-10-01

Fundamental advances in neuroscience have come from investigations into neuroplasticity and learning. These investigations often focus on identifying universal principles across different individuals of the same species. Increasingly, individual differences in learning success have also been observed, such that any seemingly universal principle might only be applicable to a certain extent within a particular learner. One potential source of this variation is individuals' genetic differences. Adult language learning provides a unique opportunity for understanding individual differences and genetic bases of neuroplasticity because of the large individual differences in learning success that have already been documented, and because of the body of empirical work connecting language learning and neurocognition. In this article, we review the literature on the genetic bases of neurocognition, especially studies examining polymorphisms of dopamine (DA)-related genes and procedural learning. This review leads us to hypothesize that there may be an association between DA-related genetic variation and language learning differences. If this hypothesis is supported by future empirical findings we suggest that it may point to neurogenetic markers that allow for language learning to be personalized. Copyright © 2012 Elsevier Srl. All rights reserved.

Inter-individual variation of selenium in maternal plasma, cord plasma and placenta

International Nuclear Information System (INIS)

Lee, Anne M.; Huel, Guy; Godin, Jean; Hellier, Georgette; Sahuquillo, Josiane; Moreau, Thierry; Blot, Phillipe

1994-01-01

Selenium (Se) in high doses has been known to cause injury to the fetus and newborn. The major difficulty in assessing the effects of selenium on human reproduction stems from the need for a suitable means of estimating maternal and fetal exposure. The present investigation, therefore, examines the respective reliability of maternal plasma, cord plasma and placenta as epidemiological indicators as well as inter-individual variation of this trace element. An unselected population of 128 pregnancies was studied. Obstetrical characteristics were noted. Selenium concentrations were determined for maternal plasma, cord plasma, and placental tissue by fluorometric analysis. Maternal plasma selenium concentrations (Se-Bm) were significantly greater than fetal concentrations (Se-Bc). Placental selenium (Se-Pl) levels were four times that of fetal levels. Variability of Se-Bc is best explained by placental concentrations. Maternal weight and ethnic origin are significantly correlated with Se-Bc. Female newborn have higher selenium levels than male newborn. The present study demonstrates the significance of the placenta as an indicator of fetal selenium exposure

Natural variation in casein composition of milk

OpenAIRE

Bijl, E.

2014-01-01

Bovine milk contains 3-4 % protein and almost 80% of the milk protein fraction consist of four caseins; αs1-casein, β-casein, αs2-casein and κ-casein. Most of the caseins in milk are assembled in casein micelles, which consist of several thousands of individual casein molecules and salts. The unique structure of casein micelles allows the delivery of large amounts of calcium and phosphate to the neonate. Considerable natural variation in casein content and composition exists between milk sam...

Retrospectively reported month-to-month variation in sleeping problems of people naturally exposed to high-amplitude annual variation in daylength and/or temperature

Directory of Open Access Journals (Sweden)

Arcady A. Putilov

Full Text Available Compared to literature on seasonal variation in mood and well-being, reports on seasonality of trouble sleeping are scarce and contradictive. To extend geography of such reports on example of people naturally exposed to high-amplitude annual variation in daylength and/or temperature. Participants were the residents of Turkmenia, West Siberia, South and North Yakutia, Chukotka, and Alaska. Health and sleep-wake adaptabilities, month-to-month variation in sleeping problems, well-being and behaviors were self-assessed. More than a half of 2398 respondents acknowledged seasonality of sleeping problems. Four of the assessed sleeping problems demonstrated three different patterns of seasonal variation. Rate of the problems significantly increased in winter months with long nights and cold days (daytime sleepiness and difficulties falling and staying asleep as well as in summer months with either long days (premature awakening and difficulties falling and staying asleep or hot nights and days (all 4 sleeping problems. Individual differences between respondents in pattern and level of seasonality of sleeping problems were significantly associated with differences in several other domains of individual variation, such as gender, age, ethnicity, physical health, morning-evening preference, sleep quality, and adaptability of the sleep-wake cycle. These results have practical relevance to understanding of the roles playing by natural environmental factors in seasonality of sleeping problems as well as to research on prevalence of sleep disorders and methods of their prevention and treatment in regions with large seasonal differences in temperature and daylength.

Individual variation of human S1P₁ coding sequence leads to heterogeneity in receptor function and drug interactions.

Science.gov (United States)

Obinata, Hideru; Gutkind, Sarah; Stitham, Jeremiah; Okuno, Toshiaki; Yokomizo, Takehiko; Hwa, John; Hla, Timothy

2014-12-01

Sphingosine 1-phosphate receptor 1 (S1P₁), an abundantly-expressed G protein-coupled receptor which regulates key vascular and immune responses, is a therapeutic target in autoimmune diseases. Fingolimod/Gilenya (FTY720), an oral medication for relapsing-remitting multiple sclerosis, targets S1P₁ receptors on immune and neural cells to suppress neuroinflammation. However, suppression of endothelial S1P₁ receptors is associated with cardiac and vascular adverse effects. Here we report the genetic variations of the S1P₁ coding region from exon sequencing of >12,000 individuals and their functional consequences. We conducted functional analyses of 14 nonsynonymous single nucleotide polymorphisms (SNPs) of the S1PR1 gene. One SNP mutant (Arg¹²⁰ to Pro) failed to transmit sphingosine 1-phosphate (S1P)-induced intracellular signals such as calcium increase and activation of p44/42 MAPK and Akt. Two other mutants (Ile⁴⁵ to Thr and Gly³⁰⁵ to Cys) showed normal intracellular signals but impaired S1P-induced endocytosis, which made the receptor resistant to FTY720-induced degradation. Another SNP mutant (Arg¹³ to Gly) demonstrated protection from coronary artery disease in a high cardiovascular risk population. Individuals with this mutation showed a significantly lower percentage of multi-vessel coronary obstruction in a risk factor-matched case-control study. This study suggests that individual genetic variations of S1P₁ can influence receptor function and, therefore, infer differential disease risks and interaction with S1P₁-targeted therapeutics. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.

Annotating individual human genomes.

Science.gov (United States)

Torkamani, Ali; Scott-Van Zeeland, Ashley A; Topol, Eric J; Schork, Nicholas J

2011-10-01

Advances in DNA sequencing technologies have made it possible to rapidly, accurately and affordably sequence entire individual human genomes. As impressive as this ability seems, however, it will not likely amount to much if one cannot extract meaningful information from individual sequence data. Annotating variations within individual genomes and providing information about their biological or phenotypic impact will thus be crucially important in moving individual sequencing projects forward, especially in the context of the clinical use of sequence information. In this paper we consider the various ways in which one might annotate individual sequence variations and point out limitations in the available methods for doing so. It is arguable that, in the foreseeable future, DNA sequencing of individual genomes will become routine for clinical, research, forensic, and personal purposes. We therefore also consider directions and areas for further research in annotating genomic variants. Copyright © 2011 Elsevier Inc. All rights reserved.

ANNOTATING INDIVIDUAL HUMAN GENOMES*

Science.gov (United States)

Torkamani, Ali; Scott-Van Zeeland, Ashley A.; Topol, Eric J.; Schork, Nicholas J.

2014-01-01

Advances in DNA sequencing technologies have made it possible to rapidly, accurately and affordably sequence entire individual human genomes. As impressive as this ability seems, however, it will not likely to amount to much if one cannot extract meaningful information from individual sequence data. Annotating variations within individual genomes and providing information about their biological or phenotypic impact will thus be crucially important in moving individual sequencing projects forward, especially in the context of the clinical use of sequence information. In this paper we consider the various ways in which one might annotate individual sequence variations and point out limitations in the available methods for doing so. It is arguable that, in the foreseeable future, DNA sequencing of individual genomes will become routine for clinical, research, forensic, and personal purposes. We therefore also consider directions and areas for further research in annotating genomic variants. PMID:21839162

Extensive Variation in Chromatin States Across Humans

KAUST Repository

Kasowski, M.

2013-10-17

The majority of disease-associated variants lie outside protein-coding regions, suggesting a link between variation in regulatory regions and disease predisposition. We studied differences in chromatin states using five histone modifications, cohesin, and CTCF in lymphoblastoid lines from 19 individuals of diverse ancestry. We found extensive signal variation in regulatory regions, which often switch between active and repressed states across individuals. Enhancer activity is particularly diverse among individuals, whereas gene expression remains relatively stable. Chromatin variability shows genetic inheritance in trios, correlates with genetic variation and population divergence, and is associated with disruptions of transcription factor binding motifs. Overall, our results provide insights into chromatin variation among humans.

Extensive Variation in Chromatin States Across Humans

KAUST Repository

Kasowski, M.; Kyriazopoulou-Panagiotopoulou, S.; Grubert, F.; Zaugg, J. B.; Kundaje, A.; Liu, Y.; Boyle, A. P.; Zhang, Q. C.; Zakharia, F.; Spacek, D. V.; Li, J.; Xie, D.; Olarerin-George, A.; Steinmetz, L. M.; Hogenesch, J. B.; Kellis, M.; Batzoglou, S.; Snyder, M.

2013-01-01

The majority of disease-associated variants lie outside protein-coding regions, suggesting a link between variation in regulatory regions and disease predisposition. We studied differences in chromatin states using five histone modifications, cohesin, and CTCF in lymphoblastoid lines from 19 individuals of diverse ancestry. We found extensive signal variation in regulatory regions, which often switch between active and repressed states across individuals. Enhancer activity is particularly diverse among individuals, whereas gene expression remains relatively stable. Chromatin variability shows genetic inheritance in trios, correlates with genetic variation and population divergence, and is associated with disruptions of transcription factor binding motifs. Overall, our results provide insights into chromatin variation among humans.

Individual variation in working memory is associated with fear extinction performance.

Science.gov (United States)

Stout, Daniel M; Acheson, Dean T; Moore, Tyler M; Gur, Ruben C; Baker, Dewleen G; Geyer, Mark A; Risbrough, Victoria B

2018-03-01

PTSD has been associated consistently with abnormalities in fear acquisition and extinction learning and retention. Fear acquisition refers to learning to discriminate between threat and safety cues. Extinction learning reflects the formation of a new inhibitory-memory that competes with a previously learned threat-related memory. Adjudicating the competition between threat memory and the new inhibitory memory during extinction may rely, in part, on cognitive processes such as working memory (WM). Despite significant shared neural circuits and signaling pathways the relationship between WM, fear acquisition, and extinction is poorly understood. Here, we analyzed data from a large sample of healthy Marines who underwent an assessment battery including tests of fear acquisition, extinction learning, and WM (N-back). Fear potentiated startle (FPS), fear expectancy ratings, and self-reported anxiety served as the primary dependent variables. High WM ability (N = 192) was associated with greater CS + fear inhibition during the late block of extinction and greater US expectancy change during extinction learning compared to individuals with low WM ability (N = 204). WM ability was not associated with magnitude of fear conditioning/expression. Attention ability was unrelated to fear acquisition or extinction supporting specificity of WM associations with extinction. These results support the conclusion that individual differences in WM may contribute to regulating fear responses. Copyright © 2018. Published by Elsevier Ltd.

Psychological distress among children and adolescents. Do individual or contextual factors matter?

DEFF Research Database (Denmark)

Meilstrup, Charlotte; Ersbøll, Annette Kjær; Nielsen, Line

Psychological distress among children and adolescents. Do individual or contextual factors matter? Authors Meilstrup C, Ersbøll AK, Nielsen L, Due P, Holstein BE Background A large minority of children and adolescents suffer from mental distress and it is important to identify contributing factors......% across schools. Individual level variables such as low socio-economic position and family composition explained much of the variation across schools. Still, class level variables also contributed to this variation. In classes where many students reported that the class-mates doesn´t like being together...... (compositional effects), this study suggest that contextual factors are important to take into account in the research on psychological complaints among children and adolescents. This analytical model presents a way for future studies about contextual influences on psychological complaints....

Epigenetic Variation in Monozygotic Twins: A Genome-Wide Analysis of DNA Methylation in Buccal Cells

NARCIS (Netherlands)

van Dongen, J.; Ehli, E.A.; Slieker, R.C.; Bartels, M.; Weber, Z.M.; Davies, G.E.; Slagboom, P.E.; Heijmans, B.T.; Boomsma, D.I.

2014-01-01

DNA methylation is one of the most extensively studied epigenetic marks in humans. Yet, it is largely unknown what causes variation in DNA methylation between individuals. The comparison of DNA methylation profiles of monozygotic (MZ) twins offers a unique experimental design to examine the extent

Spatial variations in food web structures with alternative stable states: evidence from stable isotope analysis in a large eutrophic lake

Science.gov (United States)

Li, Yunkai; Zhang, Yuying; Xu, Jun; Zhang, Shuo

2018-03-01

Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in different trophic pathways. Stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic differences between basins with different environmental characteristics. Such differences likely result from isotopic baseline differences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem.

Spatial variations in food web structures with alternative stable states: evidence from stable isotope analysis in a large eutrophic lake

Science.gov (United States)

Li, Yunkai; Zhang, Yuying; Xu, Jun; Zhang, Shuo

2017-05-01

Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in different trophic pathways. Stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic differences between basins with different environmental characteristics. Such differences likely result from isotopic baseline differences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem.

Chernobyl derived activity in sheep: variation within a single flock and with time

International Nuclear Information System (INIS)

Walters, B.

1988-01-01

The continuous monitoring of the caesium contents of sheep grazing a high fell in Cumbria, UK, is described. The technique of in-vivo monitoring, using portable NaI crystal detectors, is shown to be robust and capable of producing accurate quantitative data. Results are presented from the monitoring of 100 sheep at fortnightly intervals over a period of 13 weeks. The peak average activity (1300 Bq kg -1 ) was reached five weeks after introduction of the sheep to grazing land with up to 2000 Bq kg -1 in herbage. Activity had fallen, on average, to 68% of the peak value after eight weeks. The variation in activity between individual sheep is large and usually symmetrically distributed. The temporal trend of activity in the whole flock is a combination of the many disparate individual trends. The technique has allowed the variation between animals and individual time trends to be followed. (author)

Inter individual variations of the fish skin microbiota: host genetics basis of mutualism?

Directory of Open Access Journals (Sweden)

Sébastien Boutin

Full Text Available The commensal microbiota of fish skin is suspected to provide a protection against opportunist infections. The skin of fish harbors a complex and diverse microbiota that closely interacts with the surrounding water microbial communities. Up to now there is no clear evidence as to whether the host regulates the recruitment of environmental bacteria to build a specific skin microbiota. To address this question, we detected Quantitative Trait Loci (QTL associated with the abundance of specific skin microbiota bacterial strains in brook charr (Salvelinus fontinalis, combining 16S RNA tagged-amplicon 454 pyrosequencing with genetic linkage analysis. Skin microbiota analysis revealed high inter-individual variation among 86 F2 fish progeny based upon the relative abundance of bacterial operational taxonomic units (OTUs. Out of those OTUs, the pathogenic strain Flavobacterium psychrophilum and the non-pathogenic strain Methylobacterium rhodesianum explained the majority of inter-individual distances. Furthermore, a strong negative correlation was found between Flavobacterium and Methylobacterium, suggesting a mutually competitive relationship. Finally, after considering a total of 266 markers, genetic linkage analysis highlighted three major QTL associated with the abundance of Lysobacter, Rheinheimera and Methylobacterium. All these three genera are known for their beneficial antibacterial activity. Overall, our results provide evidence that host genotype may regulate the abundance of specific genera among their surface microbiota. They also indicate that Lysobacter, Rheinheimera and Methylobacterium are potentially important genera in providing protection against pathogens.

Examination of Automation-Induced Complacency and Individual Difference Variates

Science.gov (United States)

Prinzel, Lawrence J., III; DeVries, Holly; Freeman, Fred G.; Mikulka, Peter

2001-01-01

Automation-induced complacency has been documented as a cause or contributing factor in many airplane accidents throughout the last two decades. It is surmised that the condition results when a crew is working in highly reliable automated environments in which they serve as supervisory controllers monitoring system states for occasional automation failures. Although many reports have discussed the dangers of complacency, little empirical research has been produced to substantiate its harmful effects on performance as well as what factors produce complacency. There have been some suggestions, however, that individual characteristics could serve as possible predictors of performance in automated systems. The present study examined relationship between the individual differences of complacency potential, boredom proneness, and cognitive failure, automation-induced complacency. Workload and boredom scores were also collected and analyzed in relation to the three individual differences. The results of the study demonstrated that there are personality individual differences that are related to whether an individual will succumb to automation-induced complacency. Theoretical and practical implications are discussed.

High biological variation of serum hyaluronic acid and Hepascore, a biochemical marker model for the prediction of liver fibrosis.

Science.gov (United States)

Rossi, Enrico; Adams, Leon A; Ching, Helena L; Bulsara, Max; MacQuillan, Gerry C; Jeffrey, Gary P

2013-05-01

Serum hyaluronic acid and biochemical models which require hyaluronic acid analysis are commonly used as predictors of liver fibrosis in patients with chronic liver disease, however biological variation data for hyaluronic acid are deficient. Four serial serum samples were obtained at weekly intervals from healthy volunteers and patients with chronic hepatitis B, chronic hepatitis C and non- alcoholic fatty liver disease (NAFLD; 20 in each group). The within-individual week-to-week variation (CVI) and reference change values for hyaluronic acid, α₂-macroglobulin and Hepascore were obtained. Hepascore is calculated from hyaluronic acid, α2-macroglobulin, bilirubin and γ-glutamyltransferase activity. Hyaluronic acid displayed large within-individual variation, the CVI values were 62% in healthy subjects, 38% in hepatitis C, 37% in hepatitis B and 36% in NAFLD patients. Hepascore CVIs were 43% in healthy subjects, 24% in hepatitis C, 28% in hepatitis B and 39% in NAFLD patients. α₂-Macroglobulin was much less variable with CVIs ranging from 4.4% to 7.6%. Bland-Altman plots of week-to-week variations showed rates of significant disagreement for samples collected in any 2 successive weeks varied from 5% in NAFLD patients to 8.3% in healthy subjects. When using non-fasting serum samples, hyaluronic acid and to a lesser extent, the Hepascore model display large within-individual variations in both health and chronic liver disease. This information is critical for interpreting the significance of both single measurements and changes in serial measurements.

The Regression Analysis of Individual Financial Performance: Evidence from Croatia

OpenAIRE

Bahovec, Vlasta; Barbić, Dajana; Palić, Irena

2017-01-01

Background: A large body of empirical literature indicates that gender and financial literacy are significant determinants of individual financial performance. Objectives: The purpose of this paper is to recognize the impact of the variable financial literacy and the variable gender on the variation of the financial performance using the regression analysis. Methods/Approach: The survey was conducted using the systematically chosen random sample of Croatian financial consumers. The cross sect...

Big bees do a better job: intraspecific size variation influences pollination effectiveness

Directory of Open Access Journals (Sweden)

Pat Willmer

2014-09-01

Full Text Available 1. Bumblebees (Bombus spp. are efficient pollinators of many flowering plants, yet the pollen deposition performance of individual bees has not been investigated. Worker bumblebees exhibit large intraspecific and intra-nest size variation, in contrast with other eusocial bees; and their size influences collection and deposition of pollen grains. 2. Laboratory studies with B. terrestris workers and Vinca minor flowers showed that pollination effectiveness PE, as measured from pollen grains deposited on stigmas in single visits (SVD, was significantly positively related to bee size; larger bees deposited more grains, while the smallest individuals, with proportionally shorter tongues, were unable to collect or deposit pollen in these flowers. Individuals did not increase their pollen deposition over time, so handling experience does not influence SVD in Vinca minor. 3. Field studies using Geranium sanguineum and Echium vulgare, and multiple visiting species, confirmed that individual size affects SVD. All bumblebee species showed positive SVD/size effects, though even the smallest individuals did deposit pollen. Apis with its limited size variation showed no such detectable effect when visiting Geranium flowers. Two abundant hoverfly species also showed size effects, particularly when feeding for nectar on Echium. 4. Mean size of foragers also varied diurnally, with larger individuals active earlier and later, so that pollination effectiveness varies through a day; flowers routinely pollinated by bees may best be served by early morning dehiscence and visits from larger individuals. 5. Thus, while there are well-documented species-level variations in pollination effectiveness, the fine-scale individual differences between foragers should also be taken into account when assessing the reproductive outputs of biotically-pollinated plants.

Genomic variation among populations of threatened coral: Acropora cervicornis.

Science.gov (United States)

Drury, C; Dale, K E; Panlilio, J M; Miller, S V; Lirman, D; Larson, E A; Bartels, E; Crawford, D L; Oleksiak, M F

2016-04-13

Acropora cervicornis, a threatened, keystone reef-building coral has undergone severe declines (>90 %) throughout the Caribbean. These declines could reduce genetic variation and thus hamper the species' ability to adapt. Active restoration strategies are a common conservation approach to mitigate species' declines and require genetic data on surviving populations to efficiently respond to declines while maintaining the genetic diversity needed to adapt to changing conditions. To evaluate active restoration strategies for the staghorn coral, the genetic diversity of A. cervicornis within and among populations was assessed in 77 individuals collected from 68 locations along the Florida Reef Tract (FRT) and in the Dominican Republic. Genotyping by Sequencing (GBS) identified 4,764 single nucleotide polymorphisms (SNPs). Pairwise nucleotide differences (π) within a population are large (~37 %) and similar to π across all individuals. This high level of genetic diversity along the FRT is similar to the diversity within a small, isolated reef. Much of the genetic diversity (>90 %) exists within a population, yet GBS analysis shows significant variation along the FRT, including 300 SNPs with significant FST values and significant divergence relative to distance. There are also significant differences in SNP allele frequencies over small spatial scales, exemplified by the large FST values among corals collected within Miami-Dade county. Large standing diversity was found within each population even after recent declines in abundance, including significant, potentially adaptive divergence over short distances. The data here inform conservation and management actions by uncovering population structure and high levels of diversity maintained within coral collections among sites previously shown to have little genetic divergence. More broadly, this approach demonstrates the power of GBS to resolve differences among individuals and identify subtle genetic structure

Individual differences in normal body temperature: longitudinal big data analysis of patient records

Science.gov (United States)

Samra, Jasmeet K; Mullainathan, Sendhil

2017-01-01

Abstract Objective To estimate individual level body temperature and to correlate it with other measures of physiology and health. Design Observational cohort study. Setting Outpatient clinics of a large academic hospital, 2009-14. Participants 35 488 patients who neither received a diagnosis for infections nor were prescribed antibiotics, in whom temperature was expected to be within normal limits. Main outcome measures Baseline temperatures at individual level, estimated using random effects regression and controlling for ambient conditions at the time of measurement, body site, and time factors. Baseline temperatures were correlated with demographics, medical comorbidities, vital signs, and subsequent one year mortality. Results In a diverse cohort of 35 488 patients (mean age 52.9 years, 64% women, 41% non-white race) with 243 506 temperature measurements, mean temperature was 36.6°C (95% range 35.7-37.3°C, 99% range 35.3-37.7°C). Several demographic factors were linked to individual level temperature, with older people the coolest (–0.021°C for every decade, Ptemperature (eg, hypothyroidism: –0.013°C, P=0.01) or higher temperature (eg, cancer: 0.020, Pbody mass index: 0.002 per m/kg2, Ptemperature variation. Despite this, unexplained temperature variation was a significant predictor of subsequent mortality: controlling for all measured factors, an increase of 0.149°C (1 SD of individual temperature in the data) was linked to 8.4% higher one year mortality (P=0.014). Conclusions Individuals’ baseline temperatures showed meaningful variation that was not due solely to measurement error or environmental factors. Baseline temperatures correlated with demographics, comorbid conditions, and physiology, but these factors explained only a small part of individual temperature variation. Unexplained variation in baseline temperature, however, strongly predicted mortality. PMID:29237616

Variation in perceptions of physical dominance and trustworthiness predicts individual differences in the effect of relationship context on women's preferences for masculine pitch in men's voices.

Science.gov (United States)

Vukovic, Jovana; Jones, Benedict C; Feinberg, David R; Debruine, Lisa M; Smith, Finlay G; Welling, Lisa L M; Little, Anthony C

2011-02-01

Several studies have found that women tend to demonstrate stronger preferences for masculine men as short-term partners than as long-term partners, though there is considerable variation among women in the magnitude of this effect. One possible source of this variation is individual differences in the extent to which women perceive masculine men to possess antisocial traits that are less costly in short-term relationships than in long-term relationships. Consistent with this proposal, here we show that the extent to which women report stronger preferences for men with low (i.e., masculine) voice pitch as short-term partners than as long-term partners is associated with the extent to which they attribute physical dominance and low trustworthiness to these masculine voices. Thus, our findings suggest that variation in the extent to which women attribute negative personality characteristics to masculine men predicts individual differences in the magnitude of the effect of relationship context on women's masculinity preferences, highlighting the importance of perceived personality attributions for individual differences in women's judgments of men's vocal attractiveness and, potentially, their mate preferences. ©2010 The British Psychological Society.

Intraspecific variation in social organization by genetic variation, developmental plasticity, social flexibility or entirely extrinsic factors.

Science.gov (United States)

Schradin, Carsten

2013-05-19

Previously, it was widely believed that each species has a specific social organization, but we know now that many species show intraspecific variation in their social organization. Four different processes can lead to intraspecific variation in social organization: (i) genetic variation between individuals owing to local adaptation (between populations) or evolutionarily stable strategies within populations; (ii) developmental plasticity evolved in long-term (more than one generation) unpredictable and short-term (one generation) predictable environments, which is mediated by organizational physiological effects during early ontogeny; (iii) social flexibility evolved in highly unpredictable environments, which is mediated by activational physiological effects in adults; (iv) entirely extrinsic factors such as the death of a dominant breeder. Variation in social behaviour occurs between individuals in the case of genetic variation and developmental plasticity, but within individuals in the case of social flexibility. It is important to study intraspecific variation in social organization to understand the social systems of species because it reveals the mechanisms by which species can adapt to changing environments, offers a useful tool to study the ultimate and proximate causes of sociality, and is an interesting phenomenon by itself that needs scientific explanation.

Fission Product Release Behavior of Individual Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

Energy Technology Data Exchange (ETDEWEB)

Minato, Kazuo [Japan Atomic Energy Research Institute (Japan); Sawa, Kazuhiro [Japan Atomic Energy Research Institute (Japan); Koya, Toshio [Japan Atomic Energy Research Institute (Japan); Tomita, Takeshi [Japan Atomic Energy Research Institute (Japan); Ishikawa, Akiyoshi [Japan Atomic Energy Research Institute (Japan); Baldwin, Charles A; Gabbard, William Alexander [Oak Ridge National Laboratory (United States); Malone, Charlie M [Oak Ridge National Laboratory (United States)

2000-07-15

Postirradiation heating tests of TRISO-coated UO{sub 2} particles at 1700 and 1800degC were performed to understand fission product release behavior at accident temperatures. The inventory measurements of the individual particles were carried out before and after the heating tests with gamma-ray spectrometry to study the behavior of the individual particles. The time-dependent release behavior of {sup 85}Kr, {sup 110m}Ag, {sup 134}Cs, {sup 137}Cs, and {sup 154}Eu were obtained with on-line measurements of fission gas release and intermittent measurements of metallic fission product release during the heating tests. The inventory measurements of the individual particles revealed that fission product release behavior of the individual particles was not uniform, and large particle-to-particle variations in the release behavior of {sup 110m}Ag, {sup 134}Cs, {sup 137}Cs, and {sup 154}Eu were found. X-ray microradiography and ceramography showed that the variations could not be explained by only the presence or absence of cracks in the SiC coating layer. The SiC degradation may have been related to the variations.

Glomerular epithelial foot processes in normal man and rats. Distribution of true width and its intra- and inter-individual variation.

Science.gov (United States)

Gundersen, H J; Seefeldt, T; Osterby, R

1980-01-01

The width of individual glomerular epithelial foot processes appears very different on electron micrographs. A method for obtainining distributions of the true width of foot processes from that of their apparent width on electron micrographs has been developed based on geometric probability theory pertaining to a specific geometric model. Analyses of foot process width in humans and rats show a remarkable interindividual invariance implying rigid control and therefore great biological significance of foot process width or a derivative thereof. The very low inter-individual variation of the true width, shown in the present paper, makes it possible to demonstrate slight changes in rather small groups of patients or experimental animals.

Genic intolerance to functional variation and the interpretation of personal genomes.

Directory of Open Access Journals (Sweden)

Slavé Petrovski

Full Text Available A central challenge in interpreting personal genomes is determining which mutations most likely influence disease. Although progress has been made in scoring the functional impact of individual mutations, the characteristics of the genes in which those mutations are found remain largely unexplored. For example, genes known to carry few common functional variants in healthy individuals may be judged more likely to cause certain kinds of disease than genes known to carry many such variants. Until now, however, it has not been possible to develop a quantitative assessment of how well genes tolerate functional genetic variation on a genome-wide scale. Here we describe an effort that uses sequence data from 6503 whole exome sequences made available by the NHLBI Exome Sequencing Project (ESP. Specifically, we develop an intolerance scoring system that assesses whether genes have relatively more or less functional genetic variation than expected based on the apparently neutral variation found in the gene. To illustrate the utility of this intolerance score, we show that genes responsible for Mendelian diseases are significantly more intolerant to functional genetic variation than genes that do not cause any known disease, but with striking variation in intolerance among genes causing different classes of genetic disease. We conclude by showing that use of an intolerance ranking system can aid in interpreting personal genomes and identifying pathogenic mutations.

A database and API for variation, dense genotyping and resequencing data

Directory of Open Access Journals (Sweden)

Flicek Paul

2010-05-01

Full Text Available Abstract Background Advances in sequencing and genotyping technologies are leading to the widespread availability of multi-species variation data, dense genotype data and large-scale resequencing projects. The 1000 Genomes Project and similar efforts in other species are challenging the methods previously used for storage and manipulation of such data necessitating the redesign of existing genome-wide bioinformatics resources. Results Ensembl has created a database and software library to support data storage, analysis and access to the existing and emerging variation data from large mammalian and vertebrate genomes. These tools scale to thousands of individual genome sequences and are integrated into the Ensembl infrastructure for genome annotation and visualisation. The database and software system is easily expanded to integrate both public and non-public data sources in the context of an Ensembl software installation and is already being used outside of the Ensembl project in a number of database and application environments. Conclusions Ensembl's powerful, flexible and open source infrastructure for the management of variation, genotyping and resequencing data is freely available at http://www.ensembl.org.

Pesticide residues in individual versus composite samples of apples after fine or coarse spray quality application

DEFF Research Database (Denmark)

Poulsen, Mette E.; Wenneker, Marcel; Withagen, Jacques

2012-01-01

. None of the results for the pesticides residues measured in individual apples exceeded the EU Maximum Residue Levels (MRLs). However, there was a large variation in the residues levels in the apples, with levels from 0.01 to 1.4 mg kg−1 for captan, the pesticide with the highest variation, and from 0.......01 to 0.2 mg kg−1 for pyraclostrobin, the pesticide with the lowest variation. Residues of fenoxycarb and indoxacarb were only found in a few apples, probably due to the early application time of these two compounds. The evaluation of the effect of spray quality did not show any major difference between......In this study, field trials on fine and coarse spray quality application of pesticides on apples were performed. The main objectives were to study the variation of pesticide residue levels in individual fruits versus composite samples, and the effect of standard fine spray quality application...

Individual radiosensitivity and its relevance to health physics

International Nuclear Information System (INIS)

Schnarr, K.; Dayes, I.; Sathya, J.; Boreham, D.

2006-01-01

Full text: In the radiation protection industry, dose limits are developed to keep the workers safe. These limits assume that people have equal responses to ionizing radiation and that there is no variation in radiation risk. In radiotherapy, where patients receive large doses of radiation to their tumours and the surrounding tissue volume, 5-10% of individuals are sensitive to the treatment (adverse reactions). A radiation sensitive individual may have increased toxicity in the tissue around the tumour. This can result in necrosis, loss of organ function or even death. The cause of this sensitivity is only speculative. We postulate that this variation is due to the individual's intrinsic cellular response to radiation. Therefore, this systemic predisposition results in a lack of ability for damaged cells to be eliminated properly or repaired and consequently causes an adverse reaction. Understanding this phenomenon is crucial for radiation protection practices, since these radiosensitive individuals may also be at increased risk to high occupational or medical exposures. We have investigated individual radiosensitivity using a number of different biological endpoints. Apoptosis, or programmed cell death, was measured in human lymphocytes after receiving in vitro doses of 0, 2, 4, and 8Gy. At high doses (8Gy), radiation induced apoptosis showed a wide range of responses (mean = 34% apoptosis, o = 8.2) with z-scores ranging from -1.5 to 2.4. Low dose responses (mGy range) were also studied measuring apoptosis, DNA double strand break induction and repair in human lymphocytes exposed in vivo when patients a whole body radiation dose during diagnostic PET scans. The results showed varied individual responses and indicates that individuals may be at increased risk due to differences in DNA repair capabilities. Being able to measure radiation sensitivity would allow the radiation protection industry to tailor dose limits to an individual, reducing risk to the worker

The myth of individualism-collectivism: a critical review.

Science.gov (United States)

Voronov, Maxim; Singer, Jefferson A

2002-08-01

The authors critically assess the dimension of individualism-collectivism (I-C) and its various uses in cross-cultural psychology. They argue that I-C research is characterized largely by insufficient conceptual clarity and a lack of systematic data. As a result, they call into question the utility of I-C as an explanatory tool for cultural variation in behavior, suggest alternative dimensions for cross-cultural research, and interpret the weaknesses of research on I-C as illustrative of a general trend in social psychology.

Omics approaches to individual variation: modeling networks and the virtual patient.

Science.gov (United States)

Lehrach, Hans

2016-09-01

Every human is unique. We differ in our genomes, environment, behavior, disease history, and past and current medical treatment-a complex catalog of differences that often leads to variations in the way each of us responds to a particular therapy. We argue here that true personalization of drug therapies will rely on "virtual patient" models based on a detailed characterization of the individual patient by molecular, imaging, and sensor techniques. The models will be based, wherever possible, on the molecular mechanisms of disease processes and drug action but can also expand to hybrid models including statistics/machine learning/artificial intelligence-based elements trained on available data to address therapeutic areas or therapies for which insufficient information on mechanisms is available. Depending on the disease, its mechanisms, and the therapy, virtual patient models can be implemented at a fairly high level of abstraction, with molecular models representing cells, cell types, or organs relevant to the clinical question, interacting not only with each other but also the environment. In the future, "virtual patient/in-silico self" models may not only become a central element of our health care system, reducing otherwise unavoidable mistakes and unnecessary costs, but also act as "guardian angels" accompanying us through life to protect us against dangers and to help us to deal intelligently with our own health and wellness.

Cone-Beam Computed Tomography–Guided Positioning of Laryngeal Cancer Patients with Large Interfraction Time Trends in Setup and Nonrigid Anatomy Variations

International Nuclear Information System (INIS)

Gangsaas, Anne; Astreinidou, Eleftheria; Quint, Sandra; Levendag, Peter C.; Heijmen, Ben

2013-01-01

Purpose: To investigate interfraction setup variations of the primary tumor, elective nodes, and vertebrae in laryngeal cancer patients and to validate protocols for cone beam computed tomography (CBCT)-guided correction. Methods and Materials: For 30 patients, CBCT-measured displacements in fractionated treatments were used to investigate population setup errors and to simulate residual setup errors for the no action level (NAL) offline protocol, the extended NAL (eNAL) protocol, and daily CBCT acquisition with online analysis and repositioning. Results: Without corrections, 12 of 26 patients treated with radical radiation therapy would have experienced a gradual change (time trend) in primary tumor setup ≥4 mm in the craniocaudal (CC) direction during the fractionated treatment (11/12 in caudal direction, maximum 11 mm). Due to these trends, correction of primary tumor displacements with NAL resulted in large residual CC errors (required margin 6.7 mm). With the weekly correction vector adjustments in eNAL, the trends could be largely compensated (CC margin 3.5 mm). Correlation between movements of the primary and nodal clinical target volumes (CTVs) in the CC direction was poor (r 2 =0.15). Therefore, even with online setup corrections of the primary CTV, the required CC margin for the nodal CTV was as large as 6.8 mm. Also for the vertebrae, large time trends were observed for some patients. Because of poor CC correlation (r 2 =0.19) between displacements of the primary CTV and the vertebrae, even with daily online repositioning of the vertebrae, the required CC margin around the primary CTV was 6.9 mm. Conclusions: Laryngeal cancer patients showed substantial interfraction setup variations, including large time trends, and poor CC correlation between primary tumor displacements and motion of the nodes and vertebrae (internal tumor motion). These trends and nonrigid anatomy variations have to be considered in the choice of setup verification protocol and

Donations and dependence: Individual contributor strategies in house elections.

Science.gov (United States)

Heerwig, Jennifer A

2016-11-01

Despite the importance of individual contributors to financing federal candidates, past work has largely neglected this crucial financial constituency in favor of research on corporate and trade political action committees (PACs). By contrast, in this study I offer the first analysis of aggregate contributions from the population of individual contributors to House candidates. Using an original big dataset constructed from over fifteen million Federal Election Commission (FEC) disclosure records, I identify individual contributors (rather than contributions) and trace the variation in their strategies across types of House candidates. I distinguish between frequent donors, who are theorized to have more contact with members of Congress, versus infrequent donors in these elections. I find evidence that the character of aggregate donations from repeat donors is more access-oriented even while controlling for other salient candidate characteristics. Funds from infrequent donors, in contrast, appear more ideologically motivated. By also examining the percentage of funds that House candidates receive from repeat donors, I show that the fundraising coalitions of candidates may reproduce reliance on more access-oriented, repeat donors despite the influx of dollars from infrequent donors. I suggest that my findings provide a persuasive case for re-evaluating the diversity of roles individual contributors play in the campaign finance system, and for systematically analyzing variation in contributor strategies. Copyright © 2016 Elsevier Inc. All rights reserved.

Genetic variation of the ghrelin signalling system in individuals with amphetamine dependence.

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Suchankova, Petra; Jerlhag, Elisabet; Jayaram-Lindström, Nitya; Nilsson, Staffan; Toren, Kjell; Rosengren, Annika; Engel, Jörgen A; Franck, Johan

2013-01-01

The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL) as well as GHS-R1A (GHSR) genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs) and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104) and controls from the general population (n = 310). A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI) composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (pc  = 0.02). A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (pc  = 0.03). The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.

Genetic variation of the ghrelin signalling system in individuals with amphetamine dependence.

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Petra Suchankova

Full Text Available The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL as well as GHS-R1A (GHSR genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104 and controls from the general population (n = 310. A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (pc  = 0.02. A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (pc  = 0.03. The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.

[Correlation of intraocular pressure variation after visual field examination with 24-hour intraocular pressure variations in primary open-angle glaucoma].

Science.gov (United States)

Noro, Takahiko; Nakamoto, Kenji; Sato, Makoto; Yasuda, Noriko; Ito, Yoshinori; Ogawa, Shumpei; Nakano, Tadashi; Tsuneoka, Hiroshi

2014-10-01

We retrospectively examined intraocular pressure variations after visual field examination in primary open angle glaucoma (POAG), together with its influencing factors and its association with 24-hour intraocular pressure variations. Subjects were 94 eyes (52 POAG patients) subjected to measurements of 24-hour intraocular pressure and of changes in intraocular pressure after visual field examination using a Humphrey Visual Field Analyzer. Subjects were classified into three groups according to the magnitude of variation (large, intermediate and small), and 24-hour intraocular pressure variations were compared among the three groups. Factors influencing intraocular pressure variations after visual field examination and those associated with the large variation group were investigated. Average intraocular pressure variation after visual field examination was -0.28 ± 1.90 (range - 6.0(-) + 5.0) mmHg. No significant influencing factors were identified. The intraocular pressure at 3 a.m. was significantly higher in the large variation group than other two groups (p field examination. Increases in intraocular pressure during the night might be associated with large intraocular pressure variations after visual field examination.

Stiffness of the large arteries in individuals with and without Down syndrome

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Nunes Rodrigues A

2011-06-01

Full Text Available Anabel N Rodrigues1,2, Luan Cesar Coelho1, Washington LS Goncalves1,2, Sonia Alves Gouvea2, Maria José Rossi Vasconcellos1, Roberto S Cunha2, Glaucia R Abreu21School of Medicine, University Center of Espírito Santo, Colatina; 2Postgraduate Program in Physiological Sciences, Center for Health Sciences, Federal University of Espirito Santo, Vitória, BrazilBackground: Down syndrome is known to cause premature aging in several organ systems. However, it remains unclear whether this aging effect also affects the structure and function of the large arterial trunks. In this controlled study, the possibility of changes in the large arteries due to aging was evaluated in patients with Down syndrome.Methods: Eighty-two subjects of both genders were selected. The Down syndrome group had 41 active subjects consisting of 19 males and 22 females (mean age 21 ± 1, range 13–42 years without cardiovascular complications and who did not use vasoactive drugs. The control group consisted of 41 healthy individuals without trisomy 21 of the same gender and age as the Down syndrome group and who did not use vasoactive medication. Carotid–femoral pulse wave velocity was obtained as an index of aortic stiffness using an automatic noninvasive method.Results: Individuals with Down syndrome had significantly lower blood pressure than those in the control group. Systolic blood pressure for the Down syndrome group and control group was 106 ± 2 mmHg vs 117 ± 2 mmHg (P < 0.001, respectively; diastolic blood pressure was 66 ± 2 mmHg vs 77 ± 2 mmHg (P <0.001; and mean arterial pressure was 80 ± 1 mmHg vs 90 ± 1 mmHg (P < 0.001. Only age and systolic blood pressure were shown to correlate significantly with pulse wave velocity, but the slopes of the linear regression curves of these two variables showed no significant difference between the two study groups. Pulse wave velocity, which was initially significantly lower in the Down syndrome group (7.51 ± 0.14 m/s vs

Homogenization of Large-Scale Movement Models in Ecology

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Garlick, M.J.; Powell, J.A.; Hooten, M.B.; McFarlane, L.R.

2011-01-01

A difficulty in using diffusion models to predict large scale animal population dispersal is that individuals move differently based on local information (as opposed to gradients) in differing habitat types. This can be accommodated by using ecological diffusion. However, real environments are often spatially complex, limiting application of a direct approach. Homogenization for partial differential equations has long been applied to Fickian diffusion (in which average individual movement is organized along gradients of habitat and population density). We derive a homogenization procedure for ecological diffusion and apply it to a simple model for chronic wasting disease in mule deer. Homogenization allows us to determine the impact of small scale (10-100 m) habitat variability on large scale (10-100 km) movement. The procedure generates asymptotic equations for solutions on the large scale with parameters defined by small-scale variation. The simplicity of this homogenization procedure is striking when compared to the multi-dimensional homogenization procedure for Fickian diffusion,and the method will be equally straightforward for more complex models. ?? 2010 Society for Mathematical Biology.

Monte Carlo estimation of total variation distance of Markov chains on large spaces, with application to phylogenetics.

Science.gov (United States)

Herbei, Radu; Kubatko, Laura

2013-03-26

Markov chains are widely used for modeling in many areas of molecular biology and genetics. As the complexity of such models advances, it becomes increasingly important to assess the rate at which a Markov chain converges to its stationary distribution in order to carry out accurate inference. A common measure of convergence to the stationary distribution is the total variation distance, but this measure can be difficult to compute when the state space of the chain is large. We propose a Monte Carlo method to estimate the total variation distance that can be applied in this situation, and we demonstrate how the method can be efficiently implemented by taking advantage of GPU computing techniques. We apply the method to two Markov chains on the space of phylogenetic trees, and discuss the implications of our findings for the development of algorithms for phylogenetic inference.

Ensembl variation resources

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Marin-Garcia Pablo

2010-05-01

Full Text Available Abstract Background The maturing field of genomics is rapidly increasing the number of sequenced genomes and producing more information from those previously sequenced. Much of this additional information is variation data derived from sampling multiple individuals of a given species with the goal of discovering new variants and characterising the population frequencies of the variants that are already known. These data have immense value for many studies, including those designed to understand evolution and connect genotype to phenotype. Maximising the utility of the data requires that it be stored in an accessible manner that facilitates the integration of variation data with other genome resources such as gene annotation and comparative genomics. Description The Ensembl project provides comprehensive and integrated variation resources for a wide variety of chordate genomes. This paper provides a detailed description of the sources of data and the methods for creating the Ensembl variation databases. It also explores the utility of the information by explaining the range of query options available, from using interactive web displays, to online data mining tools and connecting directly to the data servers programmatically. It gives a good overview of the variation resources and future plans for expanding the variation data within Ensembl. Conclusions Variation data is an important key to understanding the functional and phenotypic differences between individuals. The development of new sequencing and genotyping technologies is greatly increasing the amount of variation data known for almost all genomes. The Ensembl variation resources are integrated into the Ensembl genome browser and provide a comprehensive way to access this data in the context of a widely used genome bioinformatics system. All Ensembl data is freely available at http://www.ensembl.org and from the public MySQL database server at ensembldb.ensembl.org.

Individual Variations in Inorganic Arsenic Metabolism Associated with AS3MT Genetic Polymorphisms

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Haruo Takeshita

2011-04-01

Full Text Available Individual variations in inorganic arsenic metabolism may influence the toxic effects. Arsenic (+3 oxidation state methyltransferase (AS3MT that can catalyze the transfer of a methyl group from S-adenosyl-L-methionine (AdoMet to trivalent arsenical, may play a role in arsenic metabolism in humans. Since the genetic polymorphisms of AS3MT gene may be associated with the susceptibility to inorganic arsenic toxicity, relationships of several single nucleotide polymorphisms (SNPs in AS3MT with inorganic arsenic metabolism have been investigated. Here, we summarize our recent findings and other previous studies on the inorganic arsenic metabolism and AS3MT genetic polymorphisms in humans. Results of genotype dependent differences in arsenic metabolism for most of SNPs in AS3MT were Inconsistent throughout the studies. Nevertheless, two SNPs, AS3MT 12390 (rs3740393 and 14458 (rs11191439 were consistently related to arsenic methylation regardless of the populations examined for the analysis. Thus, these SNPs may be useful indicators to predict the arsenic metabolism via methylation pathways.

Structured approaches to large-scale systems: Variational integrators for interconnected Lagrange-Dirac systems and structured model reduction on Lie groups

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Parks, Helen Frances

This dissertation presents two projects related to the structured integration of large-scale mechanical systems. Structured integration uses the considerable differential geometric structure inherent in mechanical motion to inform the design of numerical integration schemes. This process improves the qualitative properties of simulations and becomes especially valuable as a measure of accuracy over long time simulations in which traditional Gronwall accuracy estimates lose their meaning. Often, structured integration schemes replicate continuous symmetries and their associated conservation laws at the discrete level. Such is the case for variational integrators, which discretely replicate the process of deriving equations of motion from variational principles. This results in the conservation of momenta associated to symmetries in the discrete system and conservation of a symplectic form when applicable. In the case of Lagrange-Dirac systems, variational integrators preserve a discrete analogue of the Dirac structure preserved in the continuous flow. In the first project of this thesis, we extend Dirac variational integrators to accommodate interconnected systems. We hope this work will find use in the fields of control, where a controlled system can be thought of as a "plant" system joined to its controller, and in the approach of very large systems, where modular modeling may prove easier than monolithically modeling the entire system. The second project of the thesis considers a different approach to large systems. Given a detailed model of the full system, can we reduce it to a more computationally efficient model without losing essential geometric structures in the system? Asked without the reference to structure, this is the essential question of the field of model reduction. The answer there has been a resounding yes, with Principal Orthogonal Decomposition (POD) with snapshots rising as one of the most successful methods. Our project builds on previous work

Consideration of sample heterogeneity and in-depth analysis of individual differences in sensory analysis

DEFF Research Database (Denmark)

Bavay, Cécile; Brockhoff, Per B.; Kuznetsova, Alexandra

2014-01-01

In descriptive sensory analysis, large variations may be observed between scores. Individual differences between assessors have been identified as one cause for these variations. Much work has been done on modeling these differences and accounting for them through analysis of variance (ANOVA). When......, an extended version of the assessor model approach is applied. The data set used in the paper is based on sensory evaluations of three apple samples scored by a panel of 19 assessors using seven descriptors in four replicates. The application of the extended assessor model approach to unbalanced data provides...

Epigenetic Variation in Monozygotic Twins: A Genome-Wide Analysis of DNA Methylation in Buccal Cells

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Jenny van Dongen

2014-05-01

Full Text Available DNA methylation is one of the most extensively studied epigenetic marks in humans. Yet, it is largely unknown what causes variation in DNA methylation between individuals. The comparison of DNA methylation profiles of monozygotic (MZ twins offers a unique experimental design to examine the extent to which such variation is related to individual-specific environmental influences and stochastic events or to familial factors (DNA sequence and shared environment. We measured genome-wide DNA methylation in buccal samples from ten MZ pairs (age 8–19 using the Illumina 450k array and examined twin correlations for methylation level at 420,921 CpGs after QC. After selecting CpGs showing the most variation in the methylation level between subjects, the mean genome-wide correlation (rho was 0.54. The correlation was higher, on average, for CpGs within CpG islands (CGIs, compared to CGI shores, shelves and non-CGI regions, particularly at hypomethylated CpGs. This finding suggests that individual-specific environmental and stochastic influences account for more variation in DNA methylation in CpG-poor regions. Our findings also indicate that it is worthwhile to examine heritable and shared environmental influences on buccal DNA methylation in larger studies that also include dizygotic twins.

Techniques to assess biological variation in destructive data

NARCIS (Netherlands)

Tijskens, L.M.M.; Schouten, R.E.; Jongbloed, G.; Konopacki, P.J.

2018-01-01

Variation is present in all measured data, due to variation between individuals (biological variation) and variation induced by the measuring system (technical variation). Biological variation present in experimental data is not the result of a random process but strictly subject to deterministic

Geographic variation and effect of area-level poverty rate on colorectal cancer screening

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Schootman Mario

2008-10-01

Full Text Available Abstract Background With a secular trend of increasing colorectal cancer (CRC screening, concerns about disparities in CRC screening also have been rising. It is unclear if CRC screening varies geographically, if area-level poverty rate affects CRC screening, and if individual-level characteristics mediate the area-level effects on CRC screening. Methods Using 2006 Missouri Behavioral Risk Factor Surveillance System (BRFSS data, a multilevel study was conducted to examine geographic variation and the effect of area-level poverty rate on CRC screening use among persons age 50 or older. Individuals were nested within ZIP codes (ZIP5 areas, which in turn, were nested within aggregations of ZIP codes (ZIP3 areas. Six groups of individual-level covariates were considered as potential mediators. Results An estimated 51.8% of Missourians aged 50 or older adhered to CRC screening recommendations. Nearly 15% of the total variation in CRC screening lay between ZIP5 areas. Persons residing in ZIP5 areas with ≥ 10% of poverty rate had lower odds of CRC screening use than those residing in ZIP5 areas with Conclusion Large geographic variation of CRC screening exists in Missouri. Area-level poverty rate, independent of individual-level characteristics, is a significant predictor of CRC screening, but it only explains a small portion of the geographic heterogeneity of CRC screening. Individual-level factors we examined do not mediate the effect of the area-level poverty rate on CRC screening. Future studies should identify other area- and individual-level characteristics associated with CRC screening in Missouri.

Dopa decarboxylase (Ddc) affects variation in Drosophila longevity.

Science.gov (United States)

De Luca, Maria; Roshina, Nataliya V; Geiger-Thornsberry, Gretchen L; Lyman, Richard F; Pasyukova, Elena G; Mackay, Trudy F C

2003-08-01

Mutational analyses in model organisms have shown that genes affecting metabolism and stress resistance regulate life span, but the genes responsible for variation in longevity in natural populations are largely unidentified. Previously, we mapped quantitative trait loci (QTLs) affecting variation in longevity between two Drosophila melanogaster strains. Here, we show that the longevity QTL in the 36E;38B cytogenetic interval on chromosome 2 contains multiple closely linked QTLs, including the Dopa decarboxylase (Ddc) locus. Complementation tests to mutations show that Ddc is a positional candidate gene for life span in these strains. Linkage disequilibrium (LD) mapping in a sample of 173 alleles from a single population shows that three common molecular polymorphisms in Ddc account for 15.5% of the genetic contribution to variance in life span from chromosome 2. The polymorphisms are in strong LD, and the effects of the haplotypes on longevity suggest that the polymorphisms are maintained by balancing selection. DDC catalyzes the final step in the synthesis of the neurotransmitters, dopamine and serotonin. Thus, these data implicate variation in the synthesis of bioamines as a factor contributing to natural variation in individual life span.

Quasi-periodic variations of cometary ion fluxes at large distances from comet Halley

Energy Technology Data Exchange (ETDEWEB)

Richter, A.K.; Daly, P.W.; Verigin, M.I.; Gringauz, K.I.; Erdos, G.; Kecskemety, K.; Somogyi, A.J.; Szego, K.; Varga, A.; McKenna-Lawlor, S.

1989-04-01

Large variations, with a period of about 4 h, in the energetic ion fluxes have been observed far upstream (between 2 and 10 million kilometers) of comet Halley on both the Vega-1 and Giotto spacecraft. We have fitted the cometocentric distances of the occurrences to a simple model of expanding shells of neutral particles, the production of which is modulated by the spin of the comet nucleus, and have achieved excellent agreement between the two spacecraft. We derive an expansion speed for the neutrals of 6.18 +- 0.14 km s/sup -1/. Possible candidates for the neutrals are hydrogen atoms, created by the photo-dissociation of OH with a speed of 8 km s/sup -1/, or oxygen atoms, produced from the photo-dissociation of CO/sub 2/ with a speed of 6.5 km s/sup -1/.

Resection of large invasive pituitary adenomas with individualized approach under neuronavigator guidance:a report of 17 cases

OpenAIRE

Jing-min CHENG; Jian-wen GU; Yong-qin KUANG; Wei-qi HE; Xue-min XING; Hai-dong HUANG; Yuan MA; Xun XIA; Tao YANG; Xiu-zhong ZHANG; Lin CHENG; Fan-jun ZENG

2011-01-01

Objective To explore the operative method and therapeutic efficacy of surgical resection of large invasive pituitary adenomas with individualized approach under neuronavigator guidance.Methods Seventeen patients(10 males and 7 females,aged from 22 to 78 years with a mean of 39.2±9.2 years) suffering from large invasive pituitary adenoma of higher than Hardy IV grade hospitalized from 2004 to 2009 were involved in the present study.All procedures were performed with the assistance of neuronavi...

How within-group behavioural variation and task efficiency enhance fitness in a social group.

Science.gov (United States)

Pruitt, Jonathan N; Riechert, Susan E

2011-04-22

How task specialization, individual task performance and within-group behavioural variation affects fitness is a longstanding and unresolved problem in our understanding of animal societies. In the temperate social spider, Anelosimus studiosus, colony members exhibit a behavioural polymorphism; females either exhibit an aggressive 'asocial' or docile 'social' phenotype. We assessed individual prey-capture success for both phenotypes, and the role of phenotypic composition on group-level prey-capture success for three prey size classes. We then estimated the effect of group phenotypic composition on fitness in a common garden, as inferred from individual egg-case masses. On average, asocial females were more successful than social females at capturing large prey, and colony-level prey-capture success was positively associated with the frequency of the asocial phenotype. Asocial colony members were also more likely to engage in prey-capture behaviour in group-foraging situations. Interestingly, our fitness estimates indicate females of both phenotypes experience increased fitness when occupying colonies containing unlike individuals. These results imply a reciprocal fitness benefit of within-colony behavioural variation, and perhaps division of labour in a spider society.

Individual-based modeling of ecological and evolutionary processes

NARCIS (Netherlands)

DeAngelis, D.L.; Mooij, W.M.

2005-01-01

Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential and difference equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis

An extended algebraic variational multiscale-multigrid-multifractal method (XAVM4) for large-eddy simulation of turbulent two-phase flow

Science.gov (United States)

Rasthofer, U.; Wall, W. A.; Gravemeier, V.

2018-04-01

A novel and comprehensive computational method, referred to as the eXtended Algebraic Variational Multiscale-Multigrid-Multifractal Method (XAVM4), is proposed for large-eddy simulation of the particularly challenging problem of turbulent two-phase flow. The XAVM4 involves multifractal subgrid-scale modeling as well as a Nitsche-type extended finite element method as an approach for two-phase flow. The application of an advanced structural subgrid-scale modeling approach in conjunction with a sharp representation of the discontinuities at the interface between two bulk fluids promise high-fidelity large-eddy simulation of turbulent two-phase flow. The high potential of the XAVM4 is demonstrated for large-eddy simulation of turbulent two-phase bubbly channel flow, that is, turbulent channel flow carrying a single large bubble of the size of the channel half-width in this particular application.

Geographical variation in egg mass and egg content in a passerine bird.

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Suvi Ruuskanen

Full Text Available Reproductive, phenotypic and life-history traits in many animal and plant taxa show geographic variation, indicating spatial variation in selection regimes. Maternal deposition to avian eggs, such as hormones, antibodies and antioxidants, critically affect development of the offspring, with long-lasting effects on the phenotype and fitness. Little is however known about large-scale geographical patterns of variation in maternal deposition to eggs. We studied geographical variation in egg components of a passerine bird, the pied flycatcher (Ficedula hypoleuca, by collecting samples from 16 populations and measuring egg and yolk mass, albumen lysozyme activity, yolk immunoglobulins, yolk androgens and yolk total carotenoids. We found significant variation among populations in most egg components, but ca. 90% of the variation was among individuals within populations. Population however explained 40% of the variation in carotenoid levels. In contrast to our hypothesis, we found geographical trends only in carotenoids, but not in any of the other egg components. Our results thus suggest high within-population variation and leave little scope for local adaptation and genetic differentiation in deposition of different egg components. The role of these maternally-derived resources in evolutionary change should be further investigated.

Exploring language variation across Europe

DEFF Research Database (Denmark)

Hovy, Dirk; Johannsen, Anders Trærup

2016-01-01

Language varies not only between countries, but also along regional and sociodemographic lines. This variation is one of the driving factors behind language change. However, investigating language variation is a complex undertaking: the more factors we want to consider, the more data we need. Tra...... use of large amounts of data and provides statistical analyses, maps, and interactive features that enable scholars to explore language variation in a data-driven way.......Language varies not only between countries, but also along regional and sociodemographic lines. This variation is one of the driving factors behind language change. However, investigating language variation is a complex undertaking: the more factors we want to consider, the more data we need...... training in both variational linguistics and computational methods, a combination that is still not common. We take a first step here to alleviate the problem by providing an interface to explore large-scale language variation along several socio-demographic factors without programming knowledge. It makes...

Individual variation in baseline and stress-induced corticosterone and prolactin levels predicts parental effort by nesting mourning doves

Science.gov (United States)

Miller, David A.; Vleck, Carol M.; Otis, David L.

2009-01-01

Endocrine systems have an important mechanistic role in structuring life-history trade-offs. During breeding, individual variation in prolactin (PRL) and corticosterone (CORT) levels affects behavioral and physiological processes that drive trade-offs between reproduction and self-maintenance. We examined patterns in baseline (BL) and stress induced (SI; level following a standard capture-restraint protocol) levels of PRL and CORT for breeding mourning doves (Zenaida macroura). We determined whether the relationship of adult condition and parental effort to hormone levels in wild birds was consistent with life-history predictions. Both BL PRL and BL CORT level in adults were positively related to nestling weight at early nestling ages, consistent with the prediction of a positive relationship of hormone levels to current parental effort of adults and associated increased energy demand. Results are consistent with the two hormones acting together at baseline levels to limit negative effects of CORT on reproduction while maintaining beneficial effects such as increased foraging for nestling feeding. Our data did not support predictions that SI responses would vary in response to nestling or adult condition. The magnitude of CORT response in the parents to our capture-restraint protocol was negatively correlated with subsequent parental effort. Average nestling weights for adults with the highest SI CORT response were on average 10–15% lighter than expected for their age in follow-up visits after the stress event. Our results demonstrated a relationship between individual hormone levels and within population variation in parental effort and suggested that hormonal control plays an important role in structuring reproductive decisions for mourning doves.

Satisfaction with job and income among older individuals across European countries

OpenAIRE

Bonsang, E.D.M.; van Soest, A.

2010-01-01

Using data on individuals of age 50 and older from 11 European countries, we analyze two economic aspects of subjective well-being of older Europeans: satisfaction with household income, and job satisfaction. Both have been shown to contribute substantially to overall well-being (satisfaction with life or happiness). We use anchoring vignettes to correct for potential differences in response scales across countries. The results highlight a large variation in self-reported income satisfaction,...

Variational estimates of point-kinetics parameters

International Nuclear Information System (INIS)

Favorite, J.A.; Stacey, W.M. Jr.

1995-01-01

Variational estimates of the effect of flux shifts on the integral reactivity parameter of the point-kinetics equations and on regional power fractions were calculated for a variety of localized perturbations in two light water reactor (LWR) model problems representing a small, tightly coupled core and a large, loosely coupled core. For the small core, the flux shifts resulting from even relatively large localized reactivity changes (∼600 pcm) were small, and the standard point-kinetics approximation estimates of reactivity were in error by only ∼10% or less, while the variational estimates were accurate to within ∼1%. For the larger core, significant (>50%) flux shifts occurred in response to local perturbations, leading to errors of the same magnitude in the standard point-kinetics approximation of the reactivity worth. For positive reactivity, the error in the variational estimate of reactivity was only a few percent in the larger core, and the resulting transient power prediction was 1 to 2 orders of magnitude more accurate than with the standard point-kinetics approximation. For a large, local negative reactivity insertion resulting in a large flux shift, the accuracy of the variational estimate broke down. The variational estimate of the effect of flux shifts on reactivity in point-kinetics calculations of transients in LWR cores was found to generally result in greatly improved accuracy, relative to the standard point-kinetics approximation, the exception being for large negative reactivity insertions with large flux shifts in large, loosely coupled cores

Developing natural convection in a fluid layer with localized heating and large viscosity variation

Energy Technology Data Exchange (ETDEWEB)

Hickox, C.E.; Chu, Tze Yao.

1991-01-01

Numerical simulations and laboratory experiments are used to elucidate aspects of transient natural convection in a magma chamber. The magma chamber is modeled as a horizontal fluid layer confined within an enclosure of square planform and heated from below by a strip heater centered on the lower boundary of the enclosure. The width of the strip heater and the depth of the fluid layer are one-fourth of the layer width. Corn syrup is used as the working fluid in order to approximate the large viscosity variation with temperature and the large Prandtl number typical of magma. The quiescent, uniform, fluid layer is subjected to instantaneous heating from the strip heater producing a transient flow which is dominated by two counter-rotating convective cells. Experimentally determined characteristics of the developing flow are compared with numerical simulations carried out with a finite element computer program. The results of numerical simulations are in essential agreement with experimental data. Differences between the numerical simulations and experimental measurements are conjectured to result from non-ideal effects present in the experiment which are difficult to represent accurately in a numerical simulation.

Rocky intertidal macrobenthic communities across a large-scale estuarine gradient

Directory of Open Access Journals (Sweden)

Luis Giménez

2010-03-01

Full Text Available We evaluated relationships between (1 salinity and species richness and (2 frontal zones and community structure for the rocky intertidal macrobenthic community of the Uruguayan coast. A large-scale sampling design (extent ~500 km covering 9 rocky shores across 3 intertidal levels was performed between September and November 2002. The linear relationship between salinity and species richness (minimum at the freshwater extreme and the lack of correlation between variation in salinity and richness rejected two previous empirical models, explaining variations in species richness along the salinity gradient. Other factors (e.g. turbidity may explain this discrepancy. The estuarine front defined two communities—freshwater and estuarine-marine—differing in species composition and richness. The freshwater community was characterised by low richness and few individuals confined to crevices or tide pools, and must be structured by physical processes (e.g. desiccation; the estuarine-marine community, with individuals occupying almost all available substrata, must be structured by both physical and biological processes. A marine front, separating estuarine and marine habitats, had a weak effect on community structure although estuarine and marine assemblages differed according to species characterising different functional groups. We conclude that the position of the estuarine frontal zones is important for explaining large-scale patterns of community structure in the study area.

Explaining individual- and country-level variations in unregistered employment using a multi-level model: evidence from 35 Eurasian countries

Directory of Open Access Journals (Sweden)

Krasniqi Besnik A.

2017-12-01

Full Text Available The aim of this paper is to evaluate the individual- and country-level variations in unregistered employment. To analyse whether it is marginalised groups who are more likely to engage in unregistered employment and explain the country-level variations, a 2010 Life in Transition Survey (LiTS involving 38,864 interviews in 35 Eurasian countries is reported. Multilevel logistic regression analysis reveals that younger age groups, the divorced, and those with fewer years in education, are more likely to be unregistered employed. On a country-level, meanwhile, the prevalence of unregistered employment is strongly associated with tax morale; the greater the asymmetry between informal and formal institutions, the greater is the prevalence of unregistered employment. It is also higher when GDP per capita as well as social distribution and state intervention (subsidies and transfers, social contribution expenditure, health expenditure are lower. The paper concludes by discussing the theoretical and policy implications.

Temporal variation in individual factors associated with hantavirus infection in bank voles during an epizootic: implications for Puumala virus transmission dynamics.

Science.gov (United States)

Tersago, Katrien; Verhagen, Ron; Leirs, Herwig

2011-06-01

Puumala virus (PUUV), the causal agent of nephropathia epidemica in humans, is one of the many hantaviruses included in the list of emerging pathogens. Hantavirus infection is not distributed evenly among PUUV reservoir hosts (i.e., bank voles [Myodes glareolus]). Besides environmental factors and local population features, individual characteristics play an important role in vole PUUV infection risk. Identifying the relative importance of these individual characteristics can provide crucial information on PUUV transmission processes. In the present study, bank voles were monitored during the nephropathia epidemica outbreak of 2005 in Belgium. Vole sera were tested for presence of immunoglobulin G against PUUV, and a logistic mixed model was built to investigate the temporal variation in individual characteristics and their relative importance to PUUV infection risk in bank voles. Relative risk calculations for individual vole characteristics related to PUUV infection in the reservoir host show that reproductive activity dominates infection risk. The gender effect is only found in reproductively active voles, where reproductively active males have the highest infection risk. Results also revealed a clear seasonal variation in the importance of reproductive activity linked to PUUV infection. In contrast to the main effect found in other trapping sessions, no difference in infection risk ratio was found between reproductively active and nonactive voles in the spring period. Combined with increased infection risk for the reproductively nonactive group at that time, these results indicate a shift in the transmission process due to changes in bank vole behavior, physiology, or climate conditions. Hence, our results suggest that mathematical models should take into account seasonal shifts in transmission mechanisms. When these results are combined with the seasonal changes in population structure during the epizootic period, we identify vole reproductive activity and

Phenotypic integration in an extended phenotype: among-individual variation in nest-building traits of the alfalfa leafcutting bee (Megachile rotundata).

Science.gov (United States)

Royauté, Raphaël; Wilson, Elisabeth S; Helm, Bryan R; Mallinger, Rachel E; Prasifka, Jarrad; Greenlee, Kendra J; Bowsher, Julia H

2018-03-02

Structures such as nests and burrows are an essential component of many organisms' life-cycle and require a complex sequence of behaviours. Because behaviours can vary consistently among individuals and be correlated with one another, we hypothesized that these structures would (1) show evidence of among-individual variation, (2) be organized into distinct functional modules and (3) show evidence of trade-offs among functional modules due to limits on energy budgets. We tested these hypotheses using the alfalfa leafcutting bee, Megachile rotundata, a solitary bee and important crop pollinator. Megachile rotundata constructs complex nests by gathering leaf materials to form a linear series of cells in pre-existing cavities. In this study, we examined variation in the following nest construction traits: reproduction (number of cells per nest and nest length), nest protection (cap length and number of leaves per cap), cell construction (cell size and number of leaves per cell) and cell provisioning (cell mass) from 60 nests. We found a general decline in investment in cell construction and provisioning with each new cell built. In addition, we found evidence for both repeatability and plasticity in cell provisioning with little evidence for trade-offs among traits. Instead, most traits were positively, albeit weakly, correlated (r ~ 0.15), and traits were loosely organized into covarying modules. Our results show that individual differences in nest construction are detectable at a level similar to that of other behavioural traits and that these traits are only weakly integrated. This suggests that nest components are capable of independent evolutionary trajectories. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

The effect of a distinct diameter variation on the thermoelectric properties of individual Bi0.39Te0.61 nanowires

International Nuclear Information System (INIS)

Kojda, D; Mitdank, R; Fischer, S F; Mogilatenko, A; Töllner, W; Nielsch, K; Wang, Z; Kröner, M; Woias, P

2014-01-01

The reduction of the thermal conductivity induced by nano-patterning is one of the major approaches for tailoring thermoelectric material properties. In particular, the role of surface roughness and morphology is under debate. Here, we choose two individual bismuth telluride nanowires (NWs), one with a strong diameter variation between 190 nm and 320 nm (NW1) and the other of 187 nm diameter with smooth sidewalls (NW2). Both serve as model systems for which bulk properties are expected if surface properties do not contribute. We investigate the role of the diameter variation by means of a combined full-thermoelectrical, structural and chemical characterization. By transmission electron microscopy the structure, chemical composition and morphology were determined after the thermoelectrical investigation. The NWs showed an oriented growth along the [110] direction and the same composition. The Seebeck coefficients of both NWs are comparable to each other. The electrical conductivity of both NWs exceeds the bulk value indicating the presence of a topological surface state. Whereas the thermal conductivity of NW2 compares to the bulk, the thermal conductivity of NW1 is about half of NW2 which is discussed with respect to its distinct diameter variation. (invited article)

Variation of the rare earth element concentrations in the soil, soil extract and in individual plants from the same site

International Nuclear Information System (INIS)

Wyttenbach, A.; Tobler, L.; Furrer, V.; Schleppi, P.

1998-01-01

Samples of various types (spruce needles, blackberry leaves, soils, and soil extracts) have each been taken at 6 places from the same site. In addition, 4 whirls each from 2 spruce trees were sampled. Rare earth elements (REEs) were determined in these samples by neutron activation analysis with a chemical group separation. Variations between places were found to be small with soils and soil extracts, but large with plants. Variations between whirls were small. Plants neither reflected the soil nor the soil extract. Both plant species were dissimilar, but the logarithm of their ratio was a linear function of the atomic number of the REE. A negative Ce anomaly (with respect to soil) was found in both plant species. (author)

Variation in the macrofaunal community over large temporal and spatial scales in the southern Yellow Sea

Science.gov (United States)

Xu, Yong; Sui, Jixing; Yang, Mei; Sun, Yue; Li, Xinzheng; Wang, Hongfa; Zhang, Baolin

2017-09-01

To detect large, temporal- and spatial-scale variations in the macrofaunal community in the southern Yellow Sea, data collected along the western, middle and eastern regions of the southern Yellow Sea from 1958 to 2014 were organized and analyzed. Statistical methods such as cluster analysis, non-metric multidimensional scaling ordination (nMDS), permutational multivariate analysis of variance (PERMANOVA), redundancy analysis (RDA) and canonical correspondence analysis (CCA) were applied. The abundance of polychaetes increased in the western region but decreased in the eastern region from 1958 to 2014, whereas the abundance of echinoderms showed an opposite trend. For the entire macrofaunal community, Margalef's richness (d), the Shannon-Wiener index (H‧) and Pielou's evenness (J‧) were significantly lower in the eastern region when compared with the other two regions. No significant temporal differences were found for d and H‧, but there were significantly lower values of J‧ in 2014. Considerable variation in the macrofaunal community structure over the past several decades and among the geographical regions at the species, genus and family levels were observed. The species, genera and families that contributed to the temporal variation in each region were also identified. The most conspicuous pattern was the increase in the species Ophiura sarsii vadicola in the eastern region. In the western region, five polychaetes (Ninoe palmata, Notomastus latericeus, Paralacydonia paradoxa, Paraprionospio pinnata and Sternaspis scutata) increased consistently from 1958 to 2014. The dominance curves showed that both the species diversity and the dominance patterns were relatively stable in the western and middle regions. Environmental parameters such as depth, temperature and salinity could only partially explain the observed biological variation in the southern Yellow Sea. Anthropogenic activities such as demersal fishing and other unmeasured environmental variables

Individual differences in normal body temperature: longitudinal big data analysis of patient records.

Science.gov (United States)

Obermeyer, Ziad; Samra, Jasmeet K; Mullainathan, Sendhil

2017-12-13

To estimate individual level body temperature and to correlate it with other measures of physiology and health. Observational cohort study. Outpatient clinics of a large academic hospital, 2009-14. 35 488 patients who neither received a diagnosis for infections nor were prescribed antibiotics, in whom temperature was expected to be within normal limits. Baseline temperatures at individual level, estimated using random effects regression and controlling for ambient conditions at the time of measurement, body site, and time factors. Baseline temperatures were correlated with demographics, medical comorbidities, vital signs, and subsequent one year mortality. In a diverse cohort of 35 488 patients (mean age 52.9 years, 64% women, 41% non-white race) with 243 506 temperature measurements, mean temperature was 36.6°C (95% range 35.7-37.3°C, 99% range 35.3-37.7°C). Several demographic factors were linked to individual level temperature, with older people the coolest (-0.021°C for every decade, Pdata) was linked to 8.4% higher one year mortality (P=0.014). Individuals' baseline temperatures showed meaningful variation that was not due solely to measurement error or environmental factors. Baseline temperatures correlated with demographics, comorbid conditions, and physiology, but these factors explained only a small part of individual temperature variation. Unexplained variation in baseline temperature, however, strongly predicted mortality. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The effects of a stress-management training program in individuals at risk in the community at large

NARCIS (Netherlands)

Timmerman, IGH; Emmelkamp, PMG; Sanderman, R

In this study we examine the effects of a stress-management training program on individuals without serious (mental) health complaints but with an increased chance of developing them as a consequence of stress. Potential subjects were randomly selected from the community at large and, then screened

Sources of variation in innate immunity in great tit nestlings living along a metal pollution gradient: An individual-based approach

International Nuclear Information System (INIS)

Vermeulen, Anke; Müller, Wendt; Matson, Kevin D.; Irene Tieleman, B.; Bervoets, Lieven; Eens, Marcel

2015-01-01

Excessive deposition of metals in the environment is a well-known example of pollution worldwide. Chronic exposure of organisms to metals can have a detrimental effect on reproduction, behavior, health and survival, due to the negative effects on components of the immune system. However, little is known about the effects of chronic sublethal metal exposure on immunity, especially for wildlife. In our study, we examined the constitutive innate immunity of great tit (Parus major) nestlings (N = 234) living in four populations along a metal pollution gradient. For each nestling, we determined the individual metal concentrations (lead, cadmium, arsenic) present in the red blood cells and measured four different innate immune parameters (agglutination, lysis, haptoglobin concentrations and nitric oxide concentrations) to investigate the relationship between metal exposure and immunological condition. While we found significant differences in endogenous metal concentrations among populations with the highest concentrations closest to the pollution source, we did not observe corresponding patterns in our immune measures. However, when evaluating relationships between metal concentrations and immune parameters at the individual level, we found negative effects of lead and, to a lesser extent, arsenic and cadmium on lysis. In addition, high arsenic concentrations appear to elicit inflammation, as reflected by elevated haptoglobin concentrations. Thus despite the lack of a geographic association between pollution and immunity, this type of association was present at the individual level at a very early life stage. The high variation in metal concentrations and immune measures observed within populations indicates a high level of heterogeneity along an existing pollution gradient. Interestingly, we also found substantial within nest variation, for which the sources remain unclear, and which highlights the need of an individual-based approach. - Highlights: • Innate immunity

Sources of variation in innate immunity in great tit nestlings living along a metal pollution gradient: An individual-based approach

Energy Technology Data Exchange (ETDEWEB)

Vermeulen, Anke, E-mail: anke.vermeulen@uantwerpen.be [Department of Biology — Ethology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Müller, Wendt, E-mail: wendt.mueller@uantwerpen.be [Department of Biology — Ethology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Matson, Kevin D., E-mail: k.d.matson@rug.nl [Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, P.O. Box 11103, 9700 CC Groningen (Netherlands); The Resource Ecology Group, Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3a, 6708PB Wageningen (Netherlands); Irene Tieleman, B., E-mail: b.i.tieleman@rug.nl [Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, P.O. Box 11103, 9700 CC Groningen (Netherlands); Bervoets, Lieven, E-mail: lieven.bervoets@uantwerpen.be [Department of Biology — SPHERE, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Eens, Marcel, E-mail: marcel.eens@uantwerpen.be [Department of Biology — Ethology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium)

2015-03-01

Excessive deposition of metals in the environment is a well-known example of pollution worldwide. Chronic exposure of organisms to metals can have a detrimental effect on reproduction, behavior, health and survival, due to the negative effects on components of the immune system. However, little is known about the effects of chronic sublethal metal exposure on immunity, especially for wildlife. In our study, we examined the constitutive innate immunity of great tit (Parus major) nestlings (N = 234) living in four populations along a metal pollution gradient. For each nestling, we determined the individual metal concentrations (lead, cadmium, arsenic) present in the red blood cells and measured four different innate immune parameters (agglutination, lysis, haptoglobin concentrations and nitric oxide concentrations) to investigate the relationship between metal exposure and immunological condition. While we found significant differences in endogenous metal concentrations among populations with the highest concentrations closest to the pollution source, we did not observe corresponding patterns in our immune measures. However, when evaluating relationships between metal concentrations and immune parameters at the individual level, we found negative effects of lead and, to a lesser extent, arsenic and cadmium on lysis. In addition, high arsenic concentrations appear to elicit inflammation, as reflected by elevated haptoglobin concentrations. Thus despite the lack of a geographic association between pollution and immunity, this type of association was present at the individual level at a very early life stage. The high variation in metal concentrations and immune measures observed within populations indicates a high level of heterogeneity along an existing pollution gradient. Interestingly, we also found substantial within nest variation, for which the sources remain unclear, and which highlights the need of an individual-based approach. - Highlights: • Innate immunity

Seasonal and annual variation in body weight, nutrient stores and mortality of Oystercatchers Haematopus ostralegus

NARCIS (Netherlands)

Zwarts, L.; Hulscher, J.B.; Koopman, K.; Piersma, T.; Zegers, P.M.

1996-01-01

The average body weight of Oystercatchers captured in the Dutch Wadden Sea and ajoining breeding areas varies between 520 g in mid summer and 620 g in mid winter, but the individual differences remain large: between 450 and 650 g in summer and 500 and 725 g in winter. A part of this variation can be

Prediction of coronary artery calcium progression by FDG uptake of large arteries in asymptomatic individuals

Energy Technology Data Exchange (ETDEWEB)

Cho, Sang-Geon; Park, Ki Seong; Kim, Jahae; Song, Ho-Chun [Chonnam National University Hospital, Department of Nuclear Medicine, Gwang-ju (Korea, Republic of); Kang, Sae-Ryung; Kwon, Seong Young; Jabin, Zeenat; Kim, Young Jae; Jeong, Geum-Cheol; Song, Minchul; Min, Jung-Joon; Bom, Hee-Seung [Chonnam National University Hwasun Hospital, Department of Nuclear Medicine, Hwasun-gun, Jeollanam-do (Korea, Republic of); Seon, Hyun Ju [Chonnam National University Hwasun Hospital, Department of Radiology, Hwasun-gun, Jeollanam-do (Korea, Republic of)

2017-01-15

The purpose of this study is to evaluate whether fluorodeoxyglucose (FDG) uptake of the large arteries can predict coronary artery calcium (CAC) progression in asymptomatic individuals. Ninety-six asymptomatic individuals who underwent FDG positron emission tomography (PET) and CAC scoring on the same day for health screening and follow-up CAC scoring ≥1 year after baseline studies (mean 4.3 years) were included. Vascular FDG uptake was measured and corrected for blood pool activity to obtain peak and average target-to-blood pool ratios (TBRpeak and TBRavg, respectively) for the carotid arteries, and ascending and abdominal aorta. CAC scores at baseline and follow-up of each individual were measured and absolute CAC change (ΔCAC), annual CAC change (ΔCAC/year), and annual CAC change rate (ΔCAC%/year) were calculated. CAC progression was defined as ΔCAC >0 for individuals with negative baseline CAC; ΔCAC/year ≥10 for those with baseline CAC of 0large arteries is

Variation in cheliped form in two species of squat lobsters (Decapoda: Anomura from Chile

Directory of Open Access Journals (Sweden)

Aníbal H. Lezcano

2015-09-01

Full Text Available AbstractThe current study describes the variation in cheliped form of two species of squat lobsters that inhabit the continental margin off Chile: Cervimunida johni and Pleuroncodes monodon. We compared their cheliped form in the context of the reproductive strategy. The general tendency of form variation of both species is similar: chelipeds change, on average, from longer and narrower pollex with short manus to a relatively shorter and wider pollex with longer manus from small to large individuals, respectively. The degree of cheliped arching was greater in males than in females of similar carapace length, and only C. johni males showed fully arched morphology. The allometric trajectories (cheliped shape vs. carapace length were largely aligned with vectors of mean shape difference in both species. Cheliped form variation of C. johni (extended mate-guarding resembles the cheliped morphology reported for the related species Munida rugosa more than P. monodon (short mate-guarding. Our results are consistent with previous finding and suggest that the cheliped form variation (from straight and slender to a fully arched morphology is, or has been, subject to sexual selection through male-male competition for mates.

Progranulin gene variation affects serum progranulin levels differently in Danish bipolar individuals compared with healthy controls.

Science.gov (United States)

Buttenschøn, Henriette N; Nielsen, Marit N; Thotakura, Gangadaar; Lee, Chris W; Nykjær, Anders; Mors, Ole; Glerup, Simon

2017-06-01

The identification of peripheral biomarkers for bipolar disorder is of great importance and has the potential to improve diagnosis, treatment and prognosis. Recent studies have reported lower plasma progranulin levels in bipolar individuals compared with controls and association with single nucleotide polymorphisms (SNPs) within the progranulin gene (GRN). In the present study, we investigated the effect of GRN and sortilin (SORT1) gene variation on serum progranulin levels in bipolar individuals and controls. In a Danish cohort of individuals with bipolar disorder and controls, we analysed the serum progranulin level (nbipolar=80, ncontrols=76) and five SNPs located within GRN and two SNPs near the SORT1 gene encoding sortilin, a progranulin scavenger receptor known to affect circulating progranulin levels (nbipolar=166, ncontrols=186). We observed no significant difference in the serum progranulin level between cases and controls and none of the analysed SNPs located within GRN or close to SORT1 were associated with bipolar disorder. Crude and adjusted (adjusted for case-control status, sex and age) linear regression analyses showed no effect of any SNPs on the serum progranulin level. However, we observed that the mean serum progranulin level in cases and controls is affected differently depending on the genotypes of two SNPs within GRN (rs2879096 and rs4792938). The sample size is relatively small and detailed information on medication and polarity of the disorder is not available. No correction for multiple testing was performed. Our study suggests that the potential of progranulin as a biomarker for bipolar disorder is genotype dependent.

Full-Scale Modeling Explaining Large Spatial Variations of Nitrous Oxide Fluxes in a Step-Feed Plug-Flow Wastewater Treatment Reactor.

Science.gov (United States)

Ni, Bing-Jie; Pan, Yuting; van den Akker, Ben; Ye, Liu; Yuan, Zhiguo

2015-08-04

Nitrous oxide (N2O) emission data collected from wastewater treatment plants (WWTPs) show huge variations between plants and within one plant (both spatially and temporarily). Such variations and the relative contributions of various N2O production pathways are not fully understood. This study applied a previously established N2O model incorporating two currently known N2O production pathways by ammonia-oxidizing bacteria (AOB) (namely the AOB denitrification and the hydroxylamine pathways) and the N2O production pathway by heterotrophic denitrifiers to describe and provide insights into the large spatial variations of N2O fluxes in a step-feed full-scale activated sludge plant. The model was calibrated and validated by comparing simulation results with 40 days of N2O emission monitoring data as well as other water quality parameters from the plant. The model demonstrated that the relatively high biomass specific nitrogen loading rate in the Second Step of the reactor was responsible for the much higher N2O fluxes from this section. The results further revealed the AOB denitrification pathway decreased and the NH2OH oxidation pathway increased along the path of both Steps due to the increasing dissolved oxygen concentration. The overall N2O emission from this step-feed WWTP would be largely mitigated if 30% of the returned sludge were returned to the Second Step to reduce its biomass nitrogen loading rate.

Intra-individual metameric variation expressed at the enamel-dentine junction of lower post-canine dentition of South African fossil hominins and modern humans.

Science.gov (United States)

Pan, Lei; Thackeray, John Francis; Dumoncel, Jean; Zanolli, Clément; Oettlé, Anna; de Beer, Frikkie; Hoffman, Jakobus; Duployer, Benjamin; Tenailleau, Christophe; Braga, José

2017-08-01

The aim of this study is to compare the degree and patterning of inter- and intra-individual metameric variation in South African australopiths, early Homo and modern humans. Metameric variation likely reflects developmental and taxonomical issues, and could also be used to infer ecological and functional adaptations. However, its patterning along the early hominin postcanine dentition, particularly among South African fossil hominins, remains unexplored. Using microfocus X-ray computed tomography (µXCT) and geometric morphometric tools, we studied the enamel-dentine junction (EDJ) morphology and we investigated the intra- and inter-individual EDJ metameric variation among eight australopiths and two early Homo specimens from South Africa, as well as 32 modern humans. Along post-canine dentition, shape changes between metameres represented by relative positions and height of dentine horns, outlines of the EDJ occlusal table are reported in modern and fossil taxa. Comparisons of EDJ mean shapes and multivariate analyses reveal substantial variation in the direction and magnitude of metameric shape changes among taxa, but some common trends can be found. In modern humans, both the direction and magnitude of metameric shape change show increased variability in M 2 -M 3 compared to M 1 -M 2 . Fossil specimens are clustered together showing similar magnitudes of shape change. Along M 2 -M 3 , the lengths of their metameric vectors are not as variable as those of modern humans, but they display considerable variability in the direction of shape change. The distalward increase of metameric variation along the modern human molar row is consistent with the odontogenetic models of molar row structure (inhibitory cascade model). Though much remains to be tested, the variable trends and magnitudes in metamerism in fossil hominins reported here, together with differences in the scale of shape change between modern humans and fossil hominins may provide valuable information

Host behaviour and physiology underpin individual variation in avian influenza virus infection in migratory Bewick's swans.

Science.gov (United States)

Hoye, Bethany J; Fouchier, Ron A M; Klaassen, Marcel

2012-02-07

Individual variation in infection modulates both the dynamics of pathogens and their impact on host populations. It is therefore crucial to identify differential patterns of infection and understand the mechanisms responsible. Yet our understanding of infection heterogeneity in wildlife is limited, even for important zoonotic host-pathogen systems, owing to the intractability of host status prior to infection. Using novel applications of stable isotope ecology and eco-immunology, we distinguish antecedent behavioural and physiological traits associated with avian influenza virus (AIV) infection in free-living Bewick's swans (Cygnus columbianus bewickii). Swans infected with AIV exhibited higher serum δ13C (-25.3±0.4) than their non-infected counterparts (-26.3±0.2). Thus, individuals preferentially foraging in aquatic rather than terrestrial habitats experienced a higher risk of infection, suggesting that the abiotic requirements of AIV give rise to heterogeneity in pathogen exposure. Juveniles were more likely to be infected (30.8% compared with 11.3% for adults), shed approximately 15-fold higher quantity of virus and exhibited a lower specific immune response than adults. Together, these results demonstrate the potential for heterogeneity in infection to have a profound influence on the dynamics of pathogens, with concomitant impacts on host habitat selection and fitness.

Adipose tissue CIDEA is associated, independently of weight variation, to change in insulin resistance during a longitudinal weight control dietary program in obese individuals.

Science.gov (United States)

Montastier, Emilie; Déjean, Sébastien; Le Gall, Caroline; Saris, Wim H M; Langin, Dominique; Viguerie, Nathalie

2014-01-01

Weight loss reduces risk factors associated with obesity. However, long-term metabolic improvement remains a challenge. We investigated quantitative gene expression of subcutaneous adipose tissue in obese individuals and its relationship with low calorie diet and long term weight maintenance induced changes in insulin resistance. Three hundred eleven overweight and obese individuals followed a dietary protocol consisting of an 8-week low calorie diet followed by a 6-month ad libitum weight-maintenance diet. Individuals were clustered according to insulin resistance trajectories assessed using homeostasis model assessment of insulin resistance (HOMA-IR) index. Adipose tissue mRNA levels of 267 genes selected for regulation according to obesity, metabolic status and response to dieting was assessed using high throughput RT-qPCR. A combination of discriminant analyses was used to identify genes with regulation according to insulin resistance trajectories. Partial correlation was used to control for change in body mass index. Three different HOMA-IR profile groups were determined. HOMA-IR improved during low calorie diet in the 3 groups. At the end of the 6-month follow-up, groups A and B had reduced HOMA-IR by 50%. In group C, HOMA-IR had returned to baseline values. Genes were differentially expressed in the adipose tissue of individuals according to groups but a single gene, CIDEA, was common to all phases of the dietary intervention. Changes in adipose tissue CIDEA mRNA levels paralleled variations in insulin sensitivity independently of change in body mass index. Overall, CIDEA was up-regulated in adipose tissue of individuals with successful long term insulin resistance relapse and not in adipose tissue of unsuccessful individuals. The concomitant change in adipose tissue CIDEA mRNA levels and insulin sensitivity suggests a beneficial role of adipose tissue CIDEA in long term glucose homeostasis, independently of weight variation. ClinicalTrials.gov NCT00390637.

Ulysses: accurate detection of low-frequency structural variations in large insert-size sequencing libraries.

Science.gov (United States)

Gillet-Markowska, Alexandre; Richard, Hugues; Fischer, Gilles; Lafontaine, Ingrid

2015-03-15

The detection of structural variations (SVs) in short-range Paired-End (PE) libraries remains challenging because SV breakpoints can involve large dispersed repeated sequences, or carry inherent complexity, hardly resolvable with classical PE sequencing data. In contrast, large insert-size sequencing libraries (Mate-Pair libraries) provide higher physical coverage of the genome and give access to repeat-containing regions. They can thus theoretically overcome previous limitations as they are becoming routinely accessible. Nevertheless, broad insert size distributions and high rates of chimerical sequences are usually associated to this type of libraries, which makes the accurate annotation of SV challenging. Here, we present Ulysses, a tool that achieves drastically higher detection accuracy than existing tools, both on simulated and real mate-pair sequencing datasets from the 1000 Human Genome project. Ulysses achieves high specificity over the complete spectrum of variants by assessing, in a principled manner, the statistical significance of each possible variant (duplications, deletions, translocations, insertions and inversions) against an explicit model for the generation of experimental noise. This statistical model proves particularly useful for the detection of low frequency variants. SV detection performed on a large insert Mate-Pair library from a breast cancer sample revealed a high level of somatic duplications in the tumor and, to a lesser extent, in the blood sample as well. Altogether, these results show that Ulysses is a valuable tool for the characterization of somatic mosaicism in human tissues and in cancer genomes. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Specific Gravity Variation in a Lower Mississippi Valley Cottonwood Population

Science.gov (United States)

R. E. Farmer; J. R. Wilcox

1966-01-01

Specific gravity varied from 0,32 to 0.46, averaging 0.38. Most of the variation was associated with individual trees; samples within locations accounted for a smaller, but statistically significant, portion of the variation. Variation between locatians was not significant. It was concluded that individual high-density trees' should be sought throughout the...

Variation in immune parameters and disease prevalence among Lesser Black-backed Gulls (Larus fuscus sp. with different migratory strategies.

Directory of Open Access Journals (Sweden)

Elena Arriero

Full Text Available The ability to control infections is a key trait for migrants that must be balanced against other costly features of the migratory life. In this study we explored the links between migration and disease ecology by examining natural variation in parasite exposure and immunity in several populations of Lesser Black-backed Gulls (Larus fuscus with different migratory strategies. We found higher activity of natural antibodies in long distance migrants from the nominate subspecies L.f.fuscus. Circulating levels of IgY showed large variation at the population level, while immune parameters associated with antimicrobial activity showed extensive variation at the individual level irrespective of population or migratory strategy. Pathogen prevalence showed large geographical variation. However, the seroprevalence of one of the gull-specific subtypes of avian influenza (H16 was associated to the migratory strategy, with lower prevalence among the long-distance migrants, suggesting that migration may play a role in disease dynamics of certain pathogens at the population level.

Ontogenetic Variation of Individual and Total Capsaicinoids in Malagueta Peppers (Capsicum frutescens) during Fruit Maturation.

Science.gov (United States)

Fayos, Oreto; de Aguiar, Ana Carolina; Jiménez-Cantizano, Ana; Ferreiro-González, Marta; Garcés-Claver, Ana; Martínez, Julián; Mallor, Cristina; Ruiz-Rodríguez, Ana; Palma, Miguel; Barroso, Carmelo G; Barbero, Gerardo F

2017-05-03

The ontogenetic variation of total and individual capsaicinoids (nordihydrocapsaicin (n-DHC), capsaicin (C), dihydrocapsaicin (DHC), homocapsaicin (h-C) and homodihydrocapsaicin (h-DHC)) present in Malagueta pepper ( Capsicum frutescens ) during fruit ripening has been studied. Malagueta peppers were grown in a greenhouse under controlled temperature and humidity conditions. Capsaicinoids were extracted using ultrasound-assisted extraction (UAE) and the extracts were analyzed by ultra-performance liquid chromatography (UHPLC) with fluorescence detection. A significant increase in the total content of capsaicinoids was observed in the early days (between 12 and 33). Between day 33 and 40 there was a slight reduction in the total capsaicinoid content (3.3% decrease). C was the major capsaicinoid, followed by DHC, n-DHC, h-C and h-DHC. By considering the evolution of standardized values of the capsaicinoids it was verified that n-DHC, DHC and h-DHC (dihydrocapsaicin-like capsaicinoids) present a similar behavior pattern, while h-C and C (capsaicin-like capsaicinoids) show different evolution patterns.

Genetic variation of common walnut (Juglans regia in Piedmont, Northwestern Italy

Directory of Open Access Journals (Sweden)

Ferrazzini D

2007-12-01

Full Text Available The European or common walnut is a large tree prized as a multipurpose species: it provides valuable timber and produces a high-quality edible nut. The diffusion of the species in Italy has been largely influenced by the human activity, mainly through germplasm movement, selection of genotypes most suited for wood or fruit production and adaptation induced on fruit crop reproductive materials. As a consequence, genetic variability has been reduced, so that programs aimed at its preservation appear of the utmost importance. 104 walnut plants growing in Piedmont, northwestern Italy, were investigated through genetic variation scored at RAPD loci, yielded by PCR amplification of 10 decamer primers. Among the 101 studied loci, only 53 were polymorphic, showing a low level of genetic variation within the studied material. Genetic differentiation was estimated both at individual and geographical area level. Only in few cases trees growing in the same area showed to be genetically similar, while the differentiation between areas accounted for about 10% of the total variation, according to AMOVA. No significant correlation was found between genetic and geographic distances. The results of the study showed that also in Piedmont (such as it was already demonstrated in other parts of Italy the distribution of common walnut is a direct consequence of the human activity. The selection of individual trees, to be used as basic materials for seed supply, should therefore be based mainly on phenotypic traits, rather than ecological features of the location: in species characterized by artificial diffusion, the adoption of Region of Provenance has a scarce significance and prominence should be given to the phenotype selection.

Alpine ibex males grow large horns at no survival cost for most of their lifetime.

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Toïgo, Carole; Gaillard, Jean-Michel; Loison, Anne

2013-12-01

Large horns or antlers require a high energy allocation to produce and carry both physiological and social reproductive costs. Following the principle of energy allocation that implies trade-offs among fitness components, growing large weapons early in life should thus reduce future growth and survival. Evidence for such costs is ambiguous, however, partly because individual heterogeneity can counterbalance trade-offs. Individuals with larger horns or antlers may be of better quality and thus have a greater capacity to survive. We investigated trade-offs between male early horn growth and future horn growth, baseline mortality, onset of actuarial senescence, and rate of ageing in an Alpine ibex (Capra ibex ibex) population. Horn growth of males in early life was positively correlated to their horn length throughout their entire life. Cohort variation and individual heterogeneity both accounted for among-individual variation in horn length, suggesting both long-lasting effects of early life conditions and individual-specific horn growth trajectories. Early horn growth did not influence annual survival until 12 years of age, indicating that males do not invest in horn growth at survival costs over most of their lifetime. However, males with fast-growing horns early in life tended to have lower survival at very old ages. Individual heterogeneity, along with the particular life-history tactic of male ibex (weak participation to the rut until an old age after which they burn out in high mating investment), are likely to explain why the expected trade-off between horn growth and survival does not show up, at least until very old ages.

Intra and Interspecific Variations of Gene Expression Levels in Yeast Are Largely Neutral: (Nei Lecture, SMBE 2016, Gold Coast).

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Yang, Jian-Rong; Maclean, Calum J; Park, Chungoo; Zhao, Huabin; Zhang, Jianzhi

2017-09-01

It is commonly, although not universally, accepted that most intra and interspecific genome sequence variations are more or less neutral, whereas a large fraction of organism-level phenotypic variations are adaptive. Gene expression levels are molecular phenotypes that bridge the gap between genotypes and corresponding organism-level phenotypes. Yet, it is unknown whether natural variations in gene expression levels are mostly neutral or adaptive. Here we address this fundamental question by genome-wide profiling and comparison of gene expression levels in nine yeast strains belonging to three closely related Saccharomyces species and originating from five different ecological environments. We find that the transcriptome-based clustering of the nine strains approximates the genome sequence-based phylogeny irrespective of their ecological environments. Remarkably, only ∼0.5% of genes exhibit similar expression levels among strains from a common ecological environment, no greater than that among strains with comparable phylogenetic relationships but different environments. These and other observations strongly suggest that most intra and interspecific variations in yeast gene expression levels result from the accumulation of random mutations rather than environmental adaptations. This finding has profound implications for understanding the driving force of gene expression evolution, genetic basis of phenotypic adaptation, and general role of stochasticity in evolution. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Epigenetic variation, inheritance, and parent-of-origin effects of cytosine methylation in maize (Zea mays).

Science.gov (United States)

Lauria, Massimiliano; Piccinini, Sara; Pirona, Raul; Lund, Gertrud; Viotti, Angelo; Motto, Mario

2014-03-01

Pure epigenetic variation, or epigenetic variation that is independent of genetic context, may provide a mechanism for phenotypic variation in the absence of DNA mutations. To estimate the extent of pure epigenetic variation within and across generations and to identify the DNA regions targeted, a group of eight plants derived from a highly inbred line of maize (Zea mays) was analyzed by the methylation-sensitive amplified polymorphism (MSAP) technique. We found that cytosine methylation (mC) differences among individuals accounted for up to 7.4% of CCGG sites investigated by MSAP. Of the differentially methylated fragments (DMFs) identified in the S0 generation, ∼12% were meiotically inherited for at least six generations. We show that meiotically heritable mC variation was consistently generated for an average of 0.5% CCGG sites per generation and that it largely occurred somatically. We provide evidence that mC variation can be established and inherited in a parent-of-origin manner, given that the paternal lineage is more prone to both forward and reverse mC changes. The molecular characterization of selected DMFs revealed that the variation was largely determined by CG methylation changes that map within gene regions. The expression analysis of genes overlapping with DMFs did not reveal an obvious correlation between mC variation and transcription, reinforcing the idea that the primary function of gene-body methylation is not to control gene expression. Because this study focuses on epigenetic variation in field-grown plants, the data presented herein pertain to spontaneous epigenetic changes of the maize genome in a natural context.

Biological variation in tPA-induced plasma clot lysis time.

Science.gov (United States)

Talens, Simone; Malfliet, Joyce J M C; Rudež, Goran; Spronk, Henri M H; Janssen, Nicole A H; Meijer, Piet; Kluft, Cornelis; de Maat, Moniek P M; Rijken, Dingeman C

2012-10-01

Hypofibrinolysis is a risk factor for venous and arterial thrombosis, and can be assessed by using a turbidimetric tPA-induced clot lysis time (CLT) assay. Biological variation in clot lysis time may affect the interpretation and usefulness of CLT as a risk factor for thrombosis. Sufficient information about assay variation and biological variation in CLT is not yet available. Thus, this study aimed to determine the analytical, within-subject and between-subject variation in CLT. We collected blood samples from 40 healthy individuals throughout a period of one year (average 11.8 visits) and determined the CLT of each plasma sample in duplicate. The mean (± SD) CLT was 83.8 (± 11.1) minutes. The coefficients of variation for total variation, analytical variation, within-subject variation and between-subject variation were 13.4%, 2.6%, 8.2% and 10.2%, respectively. One measurement can estimate the CLT that does not deviate more than 20% from its true value. The contribution of analytical variation to the within-subject variation was 5.0%, the index of individuality was 0.84 and the reference change value was 23.8%. The CLT was longer in the morning compared to the afternoon and was slightly longer in older individuals (> 40 years) compared to younger (≤40 years) individuals. There was no seasonal variation in CLT and no association with air pollution. CLT correlated weakly with fibrinogen, C-reactive protein, prothrombin time and thrombin generation. This study provides insight into the biological variation of CLT, which can be used in future studies testing CLT as a potential risk factor for thrombosis.

Large-scale hydrology in Europe : observed patterns and model performance

Energy Technology Data Exchange (ETDEWEB)

Gudmundsson, Lukas

2011-06-15

In a changing climate, terrestrial water storages are of great interest as water availability impacts key aspects of ecosystem functioning. Thus, a better understanding of the variations of wet and dry periods will contribute to fully grasp processes of the earth system such as nutrient cycling and vegetation dynamics. Currently, river runoff from small, nearly natural, catchments is one of the few variables of the terrestrial water balance that is regularly monitored with detailed spatial and temporal coverage on large scales. River runoff, therefore, provides a foundation to approach European hydrology with respect to observed patterns on large scales, with regard to the ability of models to capture these.The analysis of observed river flow from small catchments, focused on the identification and description of spatial patterns of simultaneous temporal variations of runoff. These are dominated by large-scale variations of climatic variables but also altered by catchment processes. It was shown that time series of annual low, mean and high flows follow the same atmospheric drivers. The observation that high flows are more closely coupled to large scale atmospheric drivers than low flows, indicates the increasing influence of catchment properties on runoff under dry conditions. Further, it was shown that the low-frequency variability of European runoff is dominated by two opposing centres of simultaneous variations, such that dry years in the north are accompanied by wet years in the south.Large-scale hydrological models are simplified representations of our current perception of the terrestrial water balance on large scales. Quantification of the models strengths and weaknesses is the prerequisite for a reliable interpretation of simulation results. Model evaluations may also enable to detect shortcomings with model assumptions and thus enable a refinement of the current perception of hydrological systems. The ability of a multi model ensemble of nine large

Large-Scale Exome-wide Association Analysis Identifies Loci for White Blood Cell Traits and Pleiotropy with Immune-Mediated Diseases

NARCIS (Netherlands)

Tajuddin, S.M. (Salman M.); U.M. Schick (Ursula); Eicher, J.D. (John D.); Chami, N. (Nathalie); Giri, A. (Ayush); J. Brody (Jennifer); W.D. Hill (W. David); T. Kacprowski (Tim); Li, J. (Jin); L.-P. Lyytikäinen (Leo-Pekka); A. Manichaikul (Ani); E. Mihailov (Evelin); M.L. O'Donoghue (Michelle L.); V.S. Pankratz (Shane); R. Pazoki (Raha); Polfus, L.M. (Linda M.); A.V. Smith (Albert Vernon); C. Schurmann (Claudia); Vacchi-Suzzi, C. (Caterina); D. Waterworth (Dawn); E. Evangelou (Evangelos); L.R. Yanek (Lisa); A.D. Burt (Alastair); M.-H. Chen (Ming-Huei); F.J.A. van Rooij (Frank); J. Floyd (James); A. Greinacher (Andreas); T.B. Harris (Tamara); H. Highland (Heather); L.A. Lange (Leslie); Y. Liu (YongMei); R. Mägi (Reedik); M.A. Nalls (Michael); J. Mathias (Jasmine); D.A. Nickerson (Deborah); K. Nikus (Kjell); J.M. Starr (John); J.-C. Tardif (Jean-Claude); I. Tzoulaki; Velez Edwards, D.R. (Digna R.); L.C. Wallentin (Lars); T.M. Bartz (Traci M.); L.C. Becker (Lewis); Denny, J.C. (Joshua C.); Raffield, L.M. (Laura M.); J.D. Rioux (John); N. Friedrich (Nele); M. Fornage (Myriam); Gao, H. (He); J.N. Hirschhorn (Joel); D.C. Liewald (David C.); S.S. Rich (Stephen); A.G. Uitterlinden (André); Bastarache, L. (Lisa); D.M. Becker (Diane); E.A. Boerwinkle (Eric); de Denus, S. (Simon); E.P. Bottinger (Erwin); C. Hayward (Caroline); Hofman, A. (Albert); G. Homuth (Georg); E.M. Lange (Ethan); Launer, L.J. (Lenore J.); T. Lehtimäki (Terho); Y. Lu (Yingchang); A. Metspalu (Andres); C.J. O'Donnell (Christopher); Quarells, R.C. (Rakale C.); Richard, M. (Melissa); Torstenson, E.S. (Eric S.); K.D. Taylor (Kent); Vergnaud, A.-C. (Anne-Claire); A.B. Zonderman; D.R. Crosslin (David); I.J. Deary (Ian J.); M. Dörr (Marcus); P. Elliott (Paul); M. Evans (Michele); V. Gudnason (Vilmundur); M. Kähönen (Mika); B.M. Psaty (Bruce); Rotter, J.I. (Jerome I.); Slater, A.J. (Andrew J.); A. Dehghan (Abbas); White, H.D. (Harvey D.); S.K. Ganesh (Santhi); R.J.F. Loos (Ruth); T. Esko (Tõnu); Faraday, N. (Nauder); J.F. Wilson (James); M. Cushman (Mary Ann); A.D. Johnson (Andrew); T.L. Edwards (Todd L.); N.A. Zakai (Neil); G. Lettre (Guillaume); A. Reiner (Alexander); P. Auer (Paul)

2016-01-01

textabstractWhite blood cells play diverse roles in innate and adaptive immunity. Genetic association analyses of phenotypic variation in circulating white blood cell (WBC) counts from large samples of otherwise healthy individuals can provide insights into genes and biologic pathways involved in

Analysis of Inter-Individual Bacterial Variation in Gut of Cicada Meimuna mongolica (Hemiptera: Cicadidae).

Science.gov (United States)

Zhou, Wenting; Nan, Xiaoning; Zheng, Zhou; Wei, Cong; He, Hong

2015-01-01

Intestinal bacterial community plays a crucial role in the nutrition, development, survival, and reproduction of insects. When compared with other insects with piercing-sucking mouthparts, the habitats of cicada nymphs and adults are totally different. However, little is known about the differences in the gut bacterial communities in the nymphs and adults within any cicada species. The diversity of bacteria in the gut of nymphs and adults of both genders of Meimuna mongolica (Distant) was studied using the denaturing gradient gel electrophoresis (DGGE) method. Few inter-individual variations among gut microbiota were observed, suggesting that M. mongolica typically harbors a limited and consistent suite of bacterial species. Bacteria in the genera Pseudomonas and Enterobacter were the predominant components of the gut microflora of M. mongolica at all life stages. Bacteria of Pantoea, Streptococcus, and Uruburuella were also widespread in the cicada samples but at relatively lower concentrations. The relative stability and similarity of the PCR-DGGE patterns indicate that all individuals of this cicada species harbor a characteristic bacterial community which is independent from developmental stages and genders. Related endosymbionts that could be harbored in bacteromes of cicadas were not detected in any gut samples, which could be related to the cicada species and the distribution of these endosymbionts in the cicada cavity, or due to some of the possible limitations of PCR-DGGE community profiling. It is worthwhile to further address if related cicada endosymbiont clades distribute in the alimentary canals and other internal organs through diagnostic PCR using group-specific primer sets. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Community patterns of tropical tree phenology derived from Unmanned Aerial Vehicle images: intra- and interspecific variation, association with species plant traits, and response to interannual climate variation

Science.gov (United States)

Bohlman, Stephanie; Rifai, Sami; Park, John; Dandois, Jonathan; Muller-Landau, Helene

2017-04-01

Phenology is a key life history trait of plant species and critical driver of ecosystem processes. There is strong evidence that phenology is shifting in temperate ecosystems in response to climate change, but tropical forest phenology remains poorly quantified and understood. A key challenge is that tropical forests contain hundreds of plant species with a wide variety of phenological patterns, which makes it difficult to collect sufficient ground-based field data to characterize individual tropical tree species phenologies. Satellite-based observations, an important source of phenology data in northern latitudes, are hindered by frequent cloud cover in the tropics. To quantify phenology over a large number of individuals and species, we collected bi-weekly images from unmanned aerial vehicles (UAVs) in the well-studied 50-ha forest inventory plot on Barro Colorado Island, Panama. The objective of this study is to quantify inter- and intra-specific responses of tropical tree leaf phenology to environmental variation over large spatial scales and identify key environmental variables and physiological mechanisms underpinning phenological variation. Between October 2014 and December 2015 and again in May 2015, we collected a total of 35 sets of UAV images, each with continuous coverage of the 50-ha plot, where every tree ≥ 1 cm DBH is mapped. UAV imagery was corrected for exposure, orthorectified, and then processed to extract spectral, texture, and image information for individual tree crowns, which was then used as inputs for a machine learning algorithm that successfully predicted the percentages of leaf, branch, and flower cover for each tree crown (r2=0.76 between observed and predicted percent branch cover for individual tree crowns). We then quantified cumulative annual deciduousness for each crown by fitting a non-parametric curve of flexible shape to its predicted percent branch time series and calculated the area under the curve. We obtained the species

Development and application of an optogenetic platform for controlling and imaging a large number of individual neurons

Science.gov (United States)

Mohammed, Ali Ibrahim Ali

The understanding and treatment of brain disorders as well as the development of intelligent machines is hampered by the lack of knowledge of how the brain fundamentally functions. Over the past century, we have learned much about how individual neurons and neural networks behave, however new tools are critically needed to interrogate how neural networks give rise to complex brain processes and disease conditions. Recent innovations in molecular techniques, such as optogenetics, have enabled neuroscientists unprecedented precision to excite, inhibit and record defined neurons. The impressive sensitivity of currently available optogenetic sensors and actuators has now enabled the possibility of analyzing a large number of individual neurons in the brains of behaving animals. To promote the use of these optogenetic tools, this thesis integrates cutting edge optogenetic molecular sensors which is ultrasensitive for imaging neuronal activity with custom wide field optical microscope to analyze a large number of individual neurons in living brains. Wide-field microscopy provides a large field of view and better spatial resolution approaching the Abbe diffraction limit of fluorescent microscope. To demonstrate the advantages of this optical platform, we imaged a deep brain structure, the Hippocampus, and tracked hundreds of neurons over time while mouse was performing a memory task to investigate how those individual neurons related to behavior. In addition, we tested our optical platform in investigating transient neural network changes upon mechanical perturbation related to blast injuries. In this experiment, all blasted mice show a consistent change in neural network. A small portion of neurons showed a sustained calcium increase for an extended period of time, whereas the majority lost their activities. Finally, using optogenetic silencer to control selective motor cortex neurons, we examined their contributions to the network pathology of basal ganglia related to

Inhibitory Effects of Juices Prepared from Individual Vegetables on CYP3A4 Activity in Recombinant CYP3A4 and LS180 Cells.

Science.gov (United States)

Tsujimoto, Masayuki; Agawa, Chie; Ueda, Shinya; Yamane, Takayoshi; Kitayama, Haruna; Terao, Aya; Fukuda, Tomoya; Minegaki, Tetsuya; Nishiguchi, Kohshi

2017-01-01

Human intestinal absorption and drug metabolism vary to a large extent among individuals. For example, CYP3A4 activity has large individual variation that cannot be attributed to only genetic differences. Various flavonoids in vegetables, such as kaempferol and quercetin, possess inhibitory effects, and some vegetable and fruit juices have also been found to inhibit CYP3A4 activity. Therefore, differences in daily intake of flavonoid-containing vegetables may induce individual variation in intestinal bioavailability. To identify a vegetable that strongly inhibits CYP3A4, we investigated the effects of juices, prepared from individual vegetables, on CYP3A4 activity using recombinant CYP3A4 and LS180 cells in this study. Nine vegetable juices (cabbage, Japanese radish, onion, tomato, eggplant, carrot, Chinese cabbage, green pepper, and lettuce), were prepared and recombinant CYP3A4 and LS180 cells were used for evaluation of CYP3A4 activity. Metabolism to 6β-hydroxytestosterone by recombinant CYP3A4 was strongly inhibited by cabbage, onion, and green pepper juices, and cabbage and green pepper juices significantly inhibited CYP3A4 activity in a preincubation time-dependent manner. In addition, CYP3A4 activity in LS180 cells was significantly inhibited by cabbage and onion juices. In conclusion, this study showed that juices prepared from some individual vegetables could significantly inhibit CYP3A4 activity. Therefore, variation in the daily intake of vegetables such as cabbage and onion may be one of the factors responsible for individual differences in intestinal bioavailability.

Genomic tools for behavioural ecologists to understand repeatable individual differences in behaviour.

Science.gov (United States)

Bengston, Sarah E; Dahan, Romain A; Donaldson, Zoe; Phelps, Steven M; van Oers, Kees; Sih, Andrew; Bell, Alison M

2018-06-01

Behaviour is a key interface between an animal's genome and its environment. Repeatable individual differences in behaviour have been extensively documented in animals, but the molecular underpinnings of behavioural variation among individuals within natural populations remain largely unknown. Here, we offer a critical review of when molecular techniques may yield new insights, and we provide specific guidance on how and whether the latest tools available are appropriate given different resources, system and organismal constraints, and experimental designs. Integrating molecular genetic techniques with other strategies to study the proximal causes of behaviour provides opportunities to expand rapidly into new avenues of exploration. Such endeavours will enable us to better understand how repeatable individual differences in behaviour have evolved, how they are expressed and how they can be maintained within natural populations of animals.

Hospital Variation in Cesarean Delivery: A Multilevel Analysis.

Science.gov (United States)

Vecino-Ortiz, Andres I; Bardey, David; Castano-Yepes, Ramon

2015-12-01

To assess the issue of hospital variations in Colombia and to contribute to the methodology on health care variations by using a model that clusters the variance between hospitals while accounting for individual-level reimbursement rates and objective health-status variables. We used data on all births (N = 11,954) taking place in a contributory-regimen insurer network in Colombia during 2007. A multilevel logistic regression model was used to account for the share of unexplained variance between hospitals. In addition, an alternative variance decomposition specification was further carried out to measure the proportion of such unexplained variance due to the region effect. Hospitals account for 20% of the variation in performing cesarean sections, whereas region explains only one-third of such variance. Variables accounting for preferences on the demand side as well as reimbursement rates are found to predict the probability of performing cesarean sections. Hospital variations explain large variances within a single-payer's network. Because this insurer company is highly regarded in terms of performance and finance, these results might provide a lower bound for the scale of hospital variation in the Colombian health care market. Such lower bound provides guidance on the relevance of this issue for Colombia. Some factors such as demand-side preferences and physician reimbursement rates increase variations in health care even within a single-payer network. This is a source of inefficiencies, threatening the quality of health care and financial sustainability. The proposed methodology should be considered in further research on health care variations. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Inter- and intra-individual variation in allele-specific DNA methylation and gene expression in children conceived using assisted reproductive technology.

Directory of Open Access Journals (Sweden)

Nahid Turan

2010-07-01

Full Text Available Epidemiological studies have reported a higher incidence of rare disorders involving imprinted genes among children conceived using assisted reproductive technology (ART, suggesting that ART procedures may be disruptive to imprinted gene methylation patterns. We examined intra- and inter-individual variation in DNA methylation at the differentially methylated regions (DMRs of the IGF2/H19 and IGF2R loci in a population of children conceived in vitro or in vivo. We found substantial variation in allele-specific methylation at both loci in both groups. Aberrant methylation of the maternal IGF2/H19 DMR was more common in the in vitro group, and the overall variance was also significantly greater in the in vitro group. We estimated the number of trophoblast stem cells in each group based on approximation of the variance of the binomial distribution of IGF2/H19 methylation ratios, as well as the distribution of X chromosome inactivation scores in placenta. Both of these independent measures indicated that placentas of the in vitro group were derived from fewer stem cells than the in vivo conceived group. Both IGF2 and H19 mRNAs were significantly lower in placenta from the in vitro group. Although average birth weight was lower in the in vitro group, we found no correlation between birth weight and IGF2 or IGF2R transcript levels or the ratio of IGF2/IGF2R transcript levels. Our results show that in vitro conception is associated with aberrant methylation patterns at the IGF2/H19 locus. However, very little of the inter- or intra-individual variation in H19 or IGF2 mRNA levels can be explained by differences in maternal DMR DNA methylation, in contrast to the expectations of current transcriptional imprinting models. Extraembryonic tissues of embryos cultured in vitro appear to be derived from fewer trophoblast stem cells. It is possible that this developmental difference has an effect on placental and fetal growth.

Body size and allometric variation in facial shape in children.

Science.gov (United States)

Larson, Jacinda R; Manyama, Mange F; Cole, Joanne B; Gonzalez, Paula N; Percival, Christopher J; Liberton, Denise K; Ferrara, Tracey M; Riccardi, Sheri L; Kimwaga, Emmanuel A; Mathayo, Joshua; Spitzmacher, Jared A; Rolian, Campbell; Jamniczky, Heather A; Weinberg, Seth M; Roseman, Charles C; Klein, Ophir; Lukowiak, Ken; Spritz, Richard A; Hallgrimsson, Benedikt

2018-02-01

Morphological integration, or the tendency for covariation, is commonly seen in complex traits such as the human face. The effects of growth on shape, or allometry, represent a ubiquitous but poorly understood axis of integration. We address the question of to what extent age and measures of size converge on a single pattern of allometry for human facial shape. Our study is based on two large cross-sectional cohorts of children, one from Tanzania and the other from the United States (N = 7,173). We employ 3D facial imaging and geometric morphometrics to relate facial shape to age and anthropometric measures. The two populations differ significantly in facial shape, but the magnitude of this difference is small relative to the variation within each group. Allometric variation for facial shape is similar in both populations, representing a small but significant proportion of total variation in facial shape. Different measures of size are associated with overlapping but statistically distinct aspects of shape variation. Only half of the size-related variation in facial shape can be explained by the first principal component of four size measures and age while the remainder associates distinctly with individual measures. Allometric variation in the human face is complex and should not be regarded as a singular effect. This finding has important implications for how size is treated in studies of human facial shape and for the developmental basis for allometric variation more generally. © 2017 Wiley Periodicals, Inc.

Inferring relationships between pairs of individuals from locus heterozygosities

Directory of Open Access Journals (Sweden)

Spinetti Isabella

2002-11-01

Full Text Available Abstract Background The traditional exact method for inferring relationships between individuals from genetic data is not easily applicable in all situations that may be encountered in several fields of applied genetics. This study describes an approach that gives affordable results and is easily applicable; it is based on the probabilities that two individuals share 0, 1 or both alleles at a locus identical by state. Results We show that these probabilities (zi depend on locus heterozygosity (H, and are scarcely affected by variation of the distribution of allele frequencies. This allows us to obtain empirical curves relating zi's to H for a series of common relationships, so that the likelihood ratio of a pair of relationships between any two individuals, given their genotypes at a locus, is a function of a single parameter, H. Application to large samples of mother-child and full-sib pairs shows that the statistical power of this method to infer the correct relationship is not much lower than the exact method. Analysis of a large database of STR data proves that locus heterozygosity does not vary significantly among Caucasian populations, apart from special cases, so that the likelihood ratio of the more common relationships between pairs of individuals may be obtained by looking at tabulated zi values. Conclusions A simple method is provided, which may be used by any scientist with the help of a calculator or a spreadsheet to compute the likelihood ratios of common alternative relationships between pairs of individuals.

Prediction of individual differences in risky behavior in young adults via variations in local brain structure

Science.gov (United States)

Nasiriavanaki, Zahra; ArianNik, Mohsen; Abbassian, Abdolhosein; Mahmoudi, Elham; Roufigari, Neda; Shahzadi, Sohrab; Nasiriavanaki, Mohammadreza; Bahrami, Bahador

2015-01-01

In recent years the problem of how inter-individual differences play a role in risk-taking behavior has become a much debated issue. We investigated this problem based on the well-known balloon analog risk task (BART) in 48 healthy subjects in which participants inflate a virtual balloon opting for a higher score in the face of a riskier chance of the balloon explosion. In this study, based on a structural Voxel Based Morphometry (VBM) technique we demonstrate a significant positive correlation between BART score and size of the gray matter volume in the anterior insula in riskier subjects. Although the anterior insula is among the candidate brain areas that were involved in the risk taking behavior in fMRI studies, here based on our structural data it is the only area that was significantly related to structural variation among different subjects. PMID:26500482

Life course variations in the heritability of body size

DEFF Research Database (Denmark)

Zhao, J.; Luan, J.A.; Sharp, S.J.

aim was to use this approach to investigate the life course variations in heritability of body size. Methods: We analysed height, weight and body mass index variables at 11 time-points in 2,452 individuals (1,225 men, 1,227 women) born in 1946 and enrolled in the MRC National Survey of Health...... and Development (NSHD), with genotypes at 147,949 single nucleotide polymorphisms (SNPs) on Metabochips which were subsequently imputed to 506,255 according to the 1000Genomes project. We obtained genome-wide kinship matrices using genotypes at SNPs on Metabochips and genotypes at all SNPs, which were used.......11(0-0.20), 0.10(0-0.22) for height, weight and body mass index, respectively. Variation in estimates was also seen between alternative procedures. Conclusion: This work supports the utility of large-scale genotype data in heritability estimation and highlights the age-related variability in genetic...

Parents' Goals for Children: The Dynamic Coexistence of Individualism and Collectivism in Cultures and Individuals

Science.gov (United States)

Tamis-LeMonda, Catherine S.; Way, Niobe; Hughes, Diane; Yoshikawa, Hirokazu; Kalman, Ronit Kahana; Niwa, Erika Y.

2008-01-01

Current scholarship on the cultural value systems of individualism and collectivism, and the associated developmental goals of autonomy and relatedness, has moved beyond grand divide theories to emphasize variation within individuals and cultures. We present a theoretical model on the dynamic coexistence of cultural value systems (at the macro…

Reducing the variation in animal models by standardizing the gut microbiota

DEFF Research Database (Denmark)

Ellekilde, Merete; Hufeldt, Majbritt Ravn; Hansen, Camilla Hartmann Friis

2011-01-01

, a large proportion of laboratory animals are used to study such diseases, but inter-individual variation in these animal models leads to the need for larger group sizes to reach statistical significance and adequate power. By standardizing the microbial and immunological status of laboratory animals we...... mice changed the glucose tolerance without affecting weight or mucosal immunity. Further investigations concerning the mechanisms of how GM influences disease development is necessary, but based on these results it seems reasonable to assume that by manipulating the GM we may produce animal models...... may therefore be able to produce animals with a more standardized response and less variation. This would lead to more precise results and a reduced number of animals needed for statistical significance. Denaturing gradient gel electrophoresis (DGGE) - a culture independent approach separating PCR...

Variations in the Quality of Care at Large Public Hospitals in Beijing, China: A Condition-Based Outcome Approach.

Science.gov (United States)

Xu, Ye; Liu, Yuanli; Shu, Ting; Yang, Wei; Liang, Minghui

2015-01-01

Public hospitals deliver over ninety percent of all outpatient and inpatient services in China. Their quality is graded into three levels (A, B, and C) largely based on structural resources, but empirical evidence on the quality of process and outcome of care is extremely scarce. As expectations for quality care rise with higher living standards and cost of care, such evidence is urgently needed and vital to improve care and to inform future health reforms. We compiled and analyzed a multicenter database of over 4 million inpatient discharge summary records to provide a comprehensive assessment of the level and variations in clinical outcomes of hospitalization at 39 tertiary hospitals in Beijing. We assessed six outcome measures of clinical quality: in-hospital mortality rates (RSMR) for AMI, stroke, pneumonia and CABG, post-procedural complication rate (RS-CR), and failure-to-rescue rate (RS-FTR). The measures were adjusted for pre-admission patient case-mix using indirect standardization method with hierarchical linear mixed models. We found good overall quality with large variations by hospital and condition (mean/range, in %): RSMR-AMI: 6.23 (2.37-14.48), RSMR-stroke: 4.18 (3.58-4.44), RSMR-pneumonia: 7.78 (7.20-8.59), RSMR-CABG: 1.93 (1.55-2.23), RS-CR: 11.38 (9.9-12.88), and RS-FTR: 6.41 (5.17-7.58). Hospital grade was not significantly associated with any risk-adjusted outcome measures. Going to a higher grade public hospital does not always lead to better patient outcome because hospital grade only contains information about hospital structural resources. A hospital report card with some outcome measures of quality would provide valuable information to patients in choosing providers, and for regulators to identify gaps in health care quality. Reducing the variations in clinical practice and patient outcome should be a focus for policy makers in the next round of health sector reforms in China.

Quantum variational calculus

CERN Document Server

Malinowska, Agnieszka B

2014-01-01

This Brief puts together two subjects, quantum and variational calculi by considering variational problems involving Hahn quantum operators. The main advantage of its results is that they are able to deal with nondifferentiable (even discontinuous) functions, which are important in applications. Possible applications in economics are discussed. Economists model time as continuous or discrete. Although individual economic decisions are generally made at discrete time intervals, they may well be less than perfectly synchronized in ways discrete models postulate. On the other hand, the usual assumption that economic activity takes place continuously, is nothing else than a convenient abstraction that in many applications is far from reality. The Hahn quantum calculus helps to bridge the gap between the two families of models: continuous and discrete. Quantum Variational Calculus is self-contained and unified in presentation. It provides an opportunity for an introduction to the quantum calculus of variations fo...

Individual differences in visual perception and memory

NARCIS (Netherlands)

Colizoli, O.

2014-01-01

There is substantial variation in perception and memory in humans. There are individuals who cannot see red at all, and there are individuals who hear colors and taste words. What determines the differences and similarities between individuals' perception and memory? Can we characterize the neural

A variational analysis for large deflection of skew plates under ...

African Journals Online (AJOL)

In the present paper, the static behaviour of thin isotropic skew plates under uniformly distributed load is analyzed with the geometric nonlinearity of the model properly handled. A variational method based on total potential energy has been implemented through assumed displacement field. The computational work has ...

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

Energy Technology Data Exchange (ETDEWEB)

Tolezani, Elaine Cristina; Costa-Hong, Valéria, E-mail: hong.valeria@gmail.com; Correia, Gustavo; Mansur, Alfredo José; Drager, Luciano Ferreira; Bortolotto, Luiz Aparecido [Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

2014-11-15

Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior{sup ®} device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure related to the carotid functional measure

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

International Nuclear Information System (INIS)

Tolezani, Elaine Cristina; Costa-Hong, Valéria; Correia, Gustavo; Mansur, Alfredo José; Drager, Luciano Ferreira; Bortolotto, Luiz Aparecido

2014-01-01

Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior ® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure related to the carotid functional measure. The

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

Directory of Open Access Journals (Sweden)

Elaine Cristina Tolezani

2014-11-01

Full Text Available Background: Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. Objective: To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. Methods: This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. Results: The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01 and triglycerides (p = 0.02; intima-media thickness, to age (p < 0.01; diameter, to creatinine (p = 0.03 and age (p = 0.02; relative distensibility, to age (p < 0.01 and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively. Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01 and with relative distensibility (p < 0.01, while diameter showed a positive correlation with distensibility (p = 0.03. Conclusion: In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic

Host genetic variation influences gene expression response to rhinovirus infection.

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Minal Çalışkan

2015-04-01

Full Text Available Rhinovirus (RV is the most prevalent human respiratory virus and is responsible for at least half of all common colds. RV infections may result in a broad spectrum of effects that range from asymptomatic infections to severe lower respiratory illnesses. The basis for inter-individual variation in the response to RV infection is not well understood. In this study, we explored whether host genetic variation is associated with variation in gene expression response to RV infections between individuals. To do so, we obtained genome-wide genotype and gene expression data in uninfected and RV-infected peripheral blood mononuclear cells (PBMCs from 98 individuals. We mapped local and distant genetic variation that is associated with inter-individual differences in gene expression levels (eQTLs in both uninfected and RV-infected cells. We focused specifically on response eQTLs (reQTLs, namely, genetic associations with inter-individual variation in gene expression response to RV infection. We identified local reQTLs for 38 genes, including genes with known functions in viral response (UBA7, OAS1, IRF5 and genes that have been associated with immune and RV-related diseases (e.g., ITGA2, MSR1, GSTM3. The putative regulatory regions of genes with reQTLs were enriched for binding sites of virus-activated STAT2, highlighting the role of condition-specific transcription factors in genotype-by-environment interactions. Overall, we suggest that the 38 loci associated with inter-individual variation in gene expression response to RV-infection represent promising candidates for affecting immune and RV-related respiratory diseases.

Host genetic variation influences gene expression response to rhinovirus infection.

Science.gov (United States)

Çalışkan, Minal; Baker, Samuel W; Gilad, Yoav; Ober, Carole

2015-04-01

Rhinovirus (RV) is the most prevalent human respiratory virus and is responsible for at least half of all common colds. RV infections may result in a broad spectrum of effects that range from asymptomatic infections to severe lower respiratory illnesses. The basis for inter-individual variation in the response to RV infection is not well understood. In this study, we explored whether host genetic variation is associated with variation in gene expression response to RV infections between individuals. To do so, we obtained genome-wide genotype and gene expression data in uninfected and RV-infected peripheral blood mononuclear cells (PBMCs) from 98 individuals. We mapped local and distant genetic variation that is associated with inter-individual differences in gene expression levels (eQTLs) in both uninfected and RV-infected cells. We focused specifically on response eQTLs (reQTLs), namely, genetic associations with inter-individual variation in gene expression response to RV infection. We identified local reQTLs for 38 genes, including genes with known functions in viral response (UBA7, OAS1, IRF5) and genes that have been associated with immune and RV-related diseases (e.g., ITGA2, MSR1, GSTM3). The putative regulatory regions of genes with reQTLs were enriched for binding sites of virus-activated STAT2, highlighting the role of condition-specific transcription factors in genotype-by-environment interactions. Overall, we suggest that the 38 loci associated with inter-individual variation in gene expression response to RV-infection represent promising candidates for affecting immune and RV-related respiratory diseases.

Individual-based modeling of ecological and evolutionary processes

Science.gov (United States)

DeAngelis, Donald L.; Mooij, Wolf M.

2005-01-01

Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential-equation and difference-equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis for IBMs by describing five major types of individual variation in IBMs: spatial, ontogenetic, phenotypic, cognitive, and genetic. IBMs are now used in almost all subfields of ecology and evolutionary biology. We map those subfields and look more closely at selected key papers on fish recruitment, forest dynamics, sympatric speciation, metapopulation dynamics, maintenance of diversity, and species conservation. Theorists are currently divided on whether IBMs represent only a practical tool for extending classical theory to more complex situations, or whether individual-based theory represents a radically new research program. We feel that the tension between these two poles of thinking can be a source of creativity in ecology and evolutionary theory.

The Circadian Variation of Psychophysiological Reactivity to Stress : A Study of Individual Differences

Science.gov (United States)

1994-08-25

and/ or peak during the morning hours (Millar- Craig , Bishop, and Raftery, 1978; Turton and Deegan , 1974; and Weitzman et al., 1971). Furthermore, a...hematological factors showing distinct c i rcadian variations (e.g. Millar- Craig , Bishop, and Raftery, 1978; Weitzman, Fukushima, Nogeire, Roffwarg...examined the circadian variation o f blood pressure (BP), and have observed a morning peak in blood pressure (e.g., Millar- Craig , Bishop, & Raftery

Seasonal and Diurnal Variations of Atmospheric Non-Methane Hydrocarbons in Guangzhou, China

Directory of Open Access Journals (Sweden)

Longfeng Li

2012-05-01

Full Text Available In recent decades, high ambient ozone concentrations have become one of the major regional air quality issues in the Pearl River Delta (PRD region. Non-methane hydrocarbons (NMHCs, as key precursors of ozone, were found to be the limiting factor in photochemical ozone formation for large areas in the PRD. For source apportioning of NMHCs as well as ozone pollution control strategies, it is necessary to obtain typical seasonal and diurnal patterns of NMHCs with a large pool of field data. To date, few studies have focused on seasonal and diurnal variations of NMHCs in urban areas of Guangzhou. This study explored the seasonal variations of most hydrocarbons concentrations with autumn maximum and spring minimum in Guangzhou. The diurnal variations of most anthropogenic NMHCs typically showed two-peak pattern with one at 8:00 in the morning and another at 20:00 in the evening, both corresponding to traffic rush hours in Guangzhou, whereas isoprene displayed a different bimodal diurnal curve. Propene, ethene, m, p-xylene and toluene were the four largest contributors to ozone formation in Guangzhou, based on the evaluation of individual NMHCs’ photochemical reactivity. Therefore, an effective strategy for controlling ozone pollution may be achieved by the reduction of vehicle emissions in Guangzhou.

LEGO-NMR spectroscopy: a method to visualize individual subunits in large heteromeric complexes.

Science.gov (United States)

Mund, Markus; Overbeck, Jan H; Ullmann, Janina; Sprangers, Remco

2013-10-18

Seeing the big picture: Asymmetric macromolecular complexes that are NMR active in only a subset of their subunits can be prepared, thus decreasing NMR spectral complexity. For the hetero heptameric LSm1-7 and LSm2-8 rings NMR spectra of the individual subunits of the complete complex are obtained, showing a conserved RNA binding site. This LEGO-NMR technique makes large asymmetric complexes accessible to detailed NMR spectroscopic studies. © 2013 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of Creative Commons the Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Resection of large invasive pituitary adenomas with individualized approach under neuronavigator guidance:a report of 17 cases

Directory of Open Access Journals (Sweden)

Jing-min CHENG

2011-05-01

Full Text Available Objective To explore the operative method and therapeutic efficacy of surgical resection of large invasive pituitary adenomas with individualized approach under neuronavigator guidance.Methods Seventeen patients(10 males and 7 females,aged from 22 to 78 years with a mean of 39.2±9.2 years suffering from large invasive pituitary adenoma of higher than Hardy IV grade hospitalized from 2004 to 2009 were involved in the present study.All procedures were performed with the assistance of neuronavigator via individualized pterion approach,subfrontal extradural approach,trans-sphenoidal approach,or combined approach.The dispersedly invasive pituitary adenomas were resected under the guidance of neuronavigator by fully utilizing the natural anatomical cleavages.All the patients received follow-up CT scanning 3 days after operation,MRI scanning 1 to 3 months after operation,and clinical follow-up ranged from 6 to 72 months.The resection extent and outcome were assessed by imaging examination and clinical results.Results Total tumor removal was achieved in 15 cases,subtotal removal in 1 case,and extensive partial removal in 1 case.The visual impairment and headache were ameliorated in most cases,but in 1 patient they were worsened.Transient diabetes insipidus occurred in 8 cases,electrolyte disturbances were observed in 2 cases,leakage of cerebrospinal fluid appeared in 2 cases,hyposmia in 2 cases,visual impairment aggravated in 1 case,oculomotor nerve and abducens nerve paralysis on the operative side in 1 case,epidural hematoma in occipital and parietal regions in 1 case.No patient died during the follow-up period.Conclusions Individualized surgical approach designed according to the growth direction of tumor under neuronavigator guidance is helpful for the operators to identify the vessels and nerves in the operative field distinctly during the operation,thus the total removal rate is improved,safely of the operation to remove large invasive pituitary

Population characteristics may reduce the levels of individual call identity.

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María del Mar Delgado

Full Text Available Individual variability influences the demographic and evolutionary dynamics of spatially structured populations, and conversely ecological and evolutionary dynamics provide the context under which variations at the individual level occur. Therefore, it is essential to identify and characterize the importance of the different factors that may promote or hinder individual variability. Animal signaling is a prime example of a type of behavior that is largely dependent on both the features of individuals and the characteristics of the population to which they belong. After 10 years studying the dynamics of a population of a long-lived species, the eagle owl (Bubo bubo, we investigated the emergence and maintenance of traits that reveal individual identity by focusing on vocal features. We found that individuals inhabiting a high density population characterized by a relative lack of heterogeneity (in terms of prey availability and breeding success among breeding sites might be selected for reducing the levels of identity. Two non-mutually exclusive hypotheses may explain the structural call patterns we detected: (1 similarity in calls may be principally a consequence of the particular characteristics of the population; and (2 high density may encourage individuals to mimic each other's vocalizations in a cascade effect, leading to a widespread and unique communication network.

Large-scale geographic variation in distribution and abundance of Australian deep-water kelp forests.

Directory of Open Access Journals (Sweden)

Ezequiel M Marzinelli

Full Text Available Despite the significance of marine habitat-forming organisms, little is known about their large-scale distribution and abundance in deeper waters, where they are difficult to access. Such information is necessary to develop sound conservation and management strategies. Kelps are main habitat-formers in temperate reefs worldwide; however, these habitats are highly sensitive to environmental change. The kelp Ecklonia radiate is the major habitat-forming organism on subtidal reefs in temperate Australia. Here, we provide large-scale ecological data encompassing the latitudinal distribution along the continent of these kelp forests, which is a necessary first step towards quantitative inferences about the effects of climatic change and other stressors on these valuable habitats. We used the Autonomous Underwater Vehicle (AUV facility of Australia's Integrated Marine Observing System (IMOS to survey 157,000 m2 of seabed, of which ca 13,000 m2 were used to quantify kelp covers at multiple spatial scales (10-100 m to 100-1,000 km and depths (15-60 m across several regions ca 2-6° latitude apart along the East and West coast of Australia. We investigated the large-scale geographic variation in distribution and abundance of deep-water kelp (>15 m depth and their relationships with physical variables. Kelp cover generally increased with latitude despite great variability at smaller spatial scales. Maximum depth of kelp occurrence was 40-50 m. Kelp latitudinal distribution along the continent was most strongly related to water temperature and substratum availability. This extensive survey data, coupled with ongoing AUV missions, will allow for the detection of long-term shifts in the distribution and abundance of habitat-forming kelp and the organisms they support on a continental scale, and provide information necessary for successful implementation and management of conservation reserves.

Chuck Watson's ``differential psychoacoustics:'' Individual differences in auditory abilities

Science.gov (United States)

Kidd, Gary R.

2004-05-01

Chuck Watson was among the first in the psychoacoustic community to seriously address the topic of individual differences. At a time when there was little concern with variation among ``normal listeners'' in psychoacoustic research, Watson began a research program to document the range of human auditory abilities. The primary goals were to determine the number of distinct abilities, to specify the nature of each ability, and to document the distribution of these abilities in the general population. Thanks to Watson's talent for organizing and directing large-scale projects and his workmanlike approach to science, a large and valuable body of data on human individual differences has been collected. The research program began about 20 years ago with the study of basic auditory abilities, and it has expanded to include other modalities and cognitive/intellectual abilities in adults and children. A somewhat biased view of the importance of this work will be presented by one of Watson's many colleagues in this endeavor. The talk will provide an overview of this ongoing research program as well as a brief review of some related research by other investigators. New findings from recent extensions of this work will also be discussed.

The role of individual variation in marine larval dispersal

KAUST Repository

Nanninga, Gerrit B.; Berumen, Michael L.

2014-01-01

individuals may shape heterogeneity in patterns of connectivity. The concept of context- and condition-dependent dispersal describes the balance between the costs and benefits of dispersal that arises from the interaction of temporal and spatial landscape

On the variation of the gravitational constant G

International Nuclear Information System (INIS)

De Sabbata, V.

1980-01-01

We consider the variation of the gravitational constant G starting from Dirac's large number hypothesis. After a brief description of the various gravitational theories which, other than General Relativity, incorporate the variation of G, we consider the geophysical and astrophysical consequences of the variation of G and the present status of the performed experiments. Finally, a short account on strong gravity is given which seems to provide a basis for Dirac's large number hypothesis. (author)

HERITABLE VARIATION FOR AGGRESSION AS A REFLECTION OF INDIVIDUAL COPING STRATEGIES

NARCIS (Netherlands)

BENUS, RF; BOHUS, B; KOOLHAAS, JM; VANOORTMERSSEN, GA

1991-01-01

Evidence is presented in rodents, that individual differences in aggression reflect heritable, fundamentally different, but equally valuable alternative strategies to cope with environmental demands. Generally, aggressive individuals show an active response to aversive situations. In a social

The Role of Self-Monitoring in Assessing Individual Students' Quantity and Quality of Comments in Large-Class Discussion

Science.gov (United States)

Carstens, B. A.; Wright, J. M.; Coles, J. T.; McCleary, L. N.; Williams, R. L.

2013-01-01

This study developed a reliable and valid self-monitoring procedure for student use in recording and rating the quality of their individual comments in large college classes. Students used daily record cards immediately to record and rate each comment they made each day. However, a limit was set on the amount of credit students could claim for…

The Impact on Individualizing Student Models on Necessary Practice Opportunities

Science.gov (United States)

Lee, Jung In; Brunskill, Emma

2012-01-01

When modeling student learning, tutors that use the Knowledge Tracing framework often assume that all students have the same set of model parameters. We find that when fitting parameters to individual students, there is significant variation among the individual's parameters. We examine if this variation is important in terms of instructional…

Causal Genetic Variation Underlying Metabolome Differences.

Science.gov (United States)

Swain-Lenz, Devjanee; Nikolskiy, Igor; Cheng, Jiye; Sudarsanam, Priya; Nayler, Darcy; Staller, Max V; Cohen, Barak A

2017-08-01

An ongoing challenge in biology is to predict the phenotypes of individuals from their genotypes. Genetic variants that cause disease often change an individual's total metabolite profile, or metabolome. In light of our extensive knowledge of metabolic pathways, genetic variants that alter the metabolome may help predict novel phenotypes. To link genetic variants to changes in the metabolome, we studied natural variation in the yeast Saccharomyces cerevisiae We used an untargeted mass spectrometry method to identify dozens of metabolite Quantitative Trait Loci (mQTL), genomic regions containing genetic variation that control differences in metabolite levels between individuals. We mapped differences in urea cycle metabolites to genetic variation in specific genes known to regulate amino acid biosynthesis. Our functional assays reveal that genetic variation in two genes, AUA1 and ARG81 , cause the differences in the abundance of several urea cycle metabolites. Based on knowledge of the urea cycle, we predicted and then validated a new phenotype: sensitivity to a particular class of amino acid isomers. Our results are a proof-of-concept that untargeted mass spectrometry can reveal links between natural genetic variants and metabolome diversity. The interpretability of our results demonstrates the promise of using genetic variants underlying natural differences in the metabolome to predict novel phenotypes from genotype. Copyright © 2017 by the Genetics Society of America.

Gender-based differences in the shape of the human corpus callosum are associated with allometric variations

Science.gov (United States)

Bruner, Emiliano; de la Cuétara, José Manuel; Colom, Roberto; Martin-Loeches, Manuel

2012-01-01

The corpus callosum displays considerable morphological variability between individuals. Although some characteristics are thought to differ between male and female brains, there is no agreement regarding the source of this variation. Biomedical imaging and geometric morphometrics have provided tools to investigate shape and size variation in terms of integration and correlation. Here we analyze variations at the midsagittal outline of the corpus callosum in a sample of 102 young adults in order to describe and quantify the pattern of covariation associated with its morphology. Our results suggest that the shape of the corpus callosum is characterized by low levels of morphological integration, which explains the large variability. In larger brains, a minor allometric component involves a relative reduction of the splenium. Small differences between males and?females are associated with this allometric pattern, induced primarily by size variation rather than gender-specific characteristics. PMID:22296183

Large variations in ocular dimensions in a multiethnic population with similar genetic background.

Science.gov (United States)

Niu, Zhiqiang; Li, Jun; Zhong, Hua; Yuan, Zhonghua; Zhou, Hua; Zhang, Yang; Yuan, Yuansheng; Chen, Qin; Pan, Chen-Wei

2016-03-07

We aimed to describe the ethnic variations in ocular dimensions among three ethnic groups with similar genetic ancestry from mainland of China. We included 2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han adults aged 50 years or older in the study. Ocular dimensions including axial length (AL), anterior chamber depth (ACD), vitreous chamber depth (VCD) and lens thickness (LT) were measured using A-scan ultrasonography. Bai Chinese had longer ALs (P variations in LTs. Diabetes was associated with shallower ACDs and this association was stronger in Bai Chinese compared with Yi or Han Chinese (P for interaction = 0.02). Thicker lenses were associated with younger age (P = 0.04), male gender (P variations in cultures and lifestyles.

Electrical transport properties of large, individual NiCo{sub 2}O{sub 4} nanoplates

Energy Technology Data Exchange (ETDEWEB)

Hu, Linfeng; Wu, Limin; Hu, Xinhua; Fang, Xiaosheng [Department of Materials Science, Fudan University, Shanghai (China); Liao, Meiyong [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), Namiki, Tsukuba, Ibaraki (Japan)

2012-03-07

Understanding the electrical transport properties of individual semiconductor nanostructures is crucial to advancing their practical applications in high-performance nanodevices. Large-sized individual nanostructures with smooth surfaces are preferred because they can be easily made into nanodevices using conventional photolithography procedures rather than having to rely on costly and complex electron-beam lithography techniques. In this study, micrometer-sized NiCo{sub 2}O{sub 4} nanoplates are successfully prepared from their corresponding hydroxide precursor using a quasi-topotactic transformation. The Co/Ni atomic arrangement shows no changes during the transformation from the rhombohedral LDH precursor (space group R anti 3 m) to the cubic NiCo{sub 2}O{sub 4} spinel (space group Fd anti 3 m), and the nanoplate retains its initial morphology during the conversion process. In particular, electrical transport within an individual NiCo{sub 2}O{sub 4} nanoplate is further investigated. The mechanisms of electrical conduction in the low-temperature range (T < 100 K) can be explained in terms of the Mott's variable-range hopping model. At high temperatures (T > 100 K), both the variable-range hopping and nearest-neighbor hopping mechanisms contribute to the electrical transport properties of the NiCo{sub 2}O{sub 4} nanoplate. These initial results will be useful to understanding the fundamental characteristics of these nanoplates and to designing functional nanodevices from NiCo{sub 2}O{sub 4} nanostructures. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

High voltage distribution scheme for large size GEM detector

International Nuclear Information System (INIS)

Saini, J.; Kumar, A.; Dubey, A.K.; Negi, V.S.; Chattopadhyay, S.

2016-01-01

Gas Electron Multiplier (GEM) detectors will be used for Muon tracking in the Compressed Baryonic Matter (CBM) experiment at the Facility for Anti-proton Ion Research (FAIR) at Darmstadt, Germany. The sizes of the detector modules in the Muon chambers are of the order of 1 metre x 0.5 metre. For construction of these chambers, three GEM foils are used per chamber. These foils are made by two layered 50μm thin kapton foil. Each GEM foil has millions of holes on it. In such a large scale manufacturing of the foils, even after stringent quality controls, some of the holes may still have defects or defects might develop over the time with operating conditions. These defects may result in short-circuit of the entire GEM foil. A short even in a single hole will make entire foil un-usable. To reduce such occurrences, high voltage (HV) segmentation within the foils has been introduced. These segments are powered either by individual HV supply per segment or through an active HV distribution to manage such a large number of segments across the foil. Individual supplies apart from being costly, are highly complex to implement. Additionally, CBM will have high intensity of particles bombarding on the detector causing the change of resistive chain current feeding the GEM detector with the variation in the intensity. This leads to voltage fluctuations across the foil resulting in the gain variation with the particle intensity. Hence, a low cost active HV distribution is designed to take care of the above discussed issues

Differential DNA methylation at birth associated with mental disorder in individuals with 22q11.2 deletion syndrome

DEFF Research Database (Denmark)

Starnawska, A; Hansen, C S; Sparsø, T

2017-01-01

Individuals with 22q11.2 deletion syndrome (DS) have an increased risk of comorbid mental disorders including schizophrenia, attention deficit hyperactivity disorder, depression, as well as intellectual disability. Although most 22q11.2 deletion carriers have the long 3-Mb form of the hemizygous...... deletion, there remains a large variation in the development and progression of psychiatric disorders, which suggests that alternative factors contribute to the pathogenesis. In this study we investigated whether neonatal DNA methylation signatures in individuals with the 22q11.2 deletion associate...

Genetic Architecture of Natural Variation Underlying Adult Foraging Behavior That Is Essential for Survival of Drosophila melanogaster.

Science.gov (United States)

Lee, Yuh Chwen G; Yang, Qian; Chi, Wanhao; Turkson, Susie A; Du, Wei A; Kemkemer, Claus; Zeng, Zhao-Bang; Long, Manyuan; Zhuang, Xiaoxi

2017-05-01

Foraging behavior is critical for the fitness of individuals. However, the genetic basis of variation in foraging behavior and the evolutionary forces underlying such natural variation have rarely been investigated. We developed a systematic approach to assay the variation in survival rate in a foraging environment for adult flies derived from a wild Drosophila melanogaster population. Despite being such an essential trait, there is substantial variation of foraging behavior among D. melanogaster strains. Importantly, we provided the first evaluation of the potential caveats of using inbred Drosophila strains to perform genome-wide association studies on life-history traits, and concluded that inbreeding depression is unlikely a major contributor for the observed large variation in adult foraging behavior. We found that adult foraging behavior has a strong genetic component and, unlike larval foraging behavior, depends on multiple loci. Identified candidate genes are enriched in those with high expression in adult heads and, demonstrated by expression knock down assay, are involved in maintaining normal functions of the nervous system. Our study not only identified candidate genes for foraging behavior that is relevant to individual fitness, but also shed light on the initial stage underlying the evolution of the behavior. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Copy number variation of Fc gamma receptor genes in HIV-infected and HIV-tuberculosis co-infected individuals in sub-Saharan Africa.

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Lee R Machado

Full Text Available AIDS, caused by the retrovirus HIV, remains the largest cause of morbidity in sub-Saharan Africa yet almost all genetic studies have focused on cohorts from Western countries. HIV shows high co-morbidity with tuberculosis (TB, as HIV stimulates the reactivation of latent tuberculosis (TB. Recent clinical trials suggest that an effective anti-HIV response correlates with non-neutralising antibodies. Given that Fcγ receptors are critical in mediating the non-neutralising effects of antibodies, analysis of the extensive variation at Fcγ receptor genes is important. Single nucleotide variation and copy number variation (CNV of Fcγ receptor genes affects the expression profile, activatory/inhibitory balance, and IgG affinity of the Fcγ receptor repertoire of each individual. In this study we investigated whether CNV of FCGR2C, FCGR3A and FCGR3B as well as the HNA1 allotype of FCGR3B is associated with HIV load, response to highly-active antiretroviral therapy (HAART and co-infection with TB. We confirmed an effect of TB-co-infection status on HIV load and response to HAART, but no conclusive effect of the genetic variants we tested. We observed a small effect, in Ethiopians, of FCGR3B copy number, where deletion was more frequent in HIV-TB co-infected patients than those infected with HIV alone.

Patterns of variation at Ustilago maydis virulence clusters 2A and 19A largely reflect the demographic history of its populations.

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Ronny Kellner

Full Text Available The maintenance of an intimate interaction between plant-biotrophic fungi and their hosts over evolutionary times involves strong selection and adaptative evolution of virulence-related genes. The highly specialised maize pathogen Ustilago maydis is assigned with a high evolutionary capability to overcome host resistances due to its high rates of sexual recombination, large population sizes and long distance dispersal. Unlike most studied fungus-plant interactions, the U. maydis - Zea mays pathosystem lacks a typical gene-for-gene interaction. It exerts a large set of secreted fungal virulence factors that are mostly organised in gene clusters. Their contribution to virulence has been experimentally demonstrated but their genetic diversity within U. maydis remains poorly understood. Here, we report on the intraspecific diversity of 34 potential virulence factor genes of U. maydis. We analysed their sequence polymorphisms in 17 isolates of U. maydis from Europe, North and Latin America. We focused on gene cluster 2A, associated with virulence attenuation, cluster 19A that is crucial for virulence, and the cluster-independent effector gene pep1. Although higher compared to four house-keeping genes, the overall levels of intraspecific genetic variation of virulence clusters 2A and 19A, and pep1 are remarkably low and commensurate to the levels of 14 studied non-virulence genes. In addition, each gene is present in all studied isolates and synteny in cluster 2A is conserved. Furthermore, 7 out of 34 virulence genes contain either no polymorphisms or only synonymous substitutions among all isolates. However, genetic variation of clusters 2A and 19A each resolve the large scale population structure of U. maydis indicating subpopulations with decreased gene flow. Hence, the genetic diversity of these virulence-related genes largely reflect the demographic history of U. maydis populations.

Variations among Japanese of the factor IX gene (F9) detected by PCR-denaturing gradient gel electrophoresis

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Satoh, Chiyoko; Takahashi, Norio; Asakawa, Junichi; Hiyama, Keiko; Kodaira, Meiko (Radiation Effects Research Foundation, Hiroshima (Japan))

1993-01-01

In the course of feasibility studies to examine the efficiencies and practicalities of various techniques for screening for genetic variations, the human coagulation factor IX (F9) genes of 63 Japanese families were examined by PCR-denaturing gradient gel electrophoresis (PCR-DGGE). Four target sequences with lengths of 983-2,891 bp from the F9 genes of 126 unrelated individuals from Hiroshima and their 100 children were amplified by PCR, digested with restriction enzymes to approximately 500-bp fragments, and examined by DGGE - a total of 6,724 bp being examined per individual. GC-rich sequences (GC-clamps) of 40 bp were attached to both ends of the target sequences, as far as was feasible. Eleven types of new nucleotide substitutions were detected in the population, none of which produced RFLPs or caused hemophilia B. By examining two target sequences in a single lane, approximately 8,000 bp in a diploid individual could be examined. This approach is very effective for the detection of variations in DNA and is applicable to large-scale population studies. 46 refs., 3 figs., 1 tab.

Inhibition and Updating, but Not Switching, Predict Developmental Dyslexia and Individual Variation in Reading Ability

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Caoilainn Doyle

2018-05-01

Full Text Available To elucidate the core executive function profile (strengths and weaknesses in inhibition, updating, and switching associated with dyslexia, this study explored executive function in 27 children with dyslexia and 29 age matched controls using sensitive z-mean measures of each ability and controlled for individual differences in processing speed. This study found that developmental dyslexia is associated with inhibition and updating, but not switching impairments, at the error z-mean composite level, whilst controlling for processing speed. Inhibition and updating (but not switching error composites predicted both dyslexia likelihood and reading ability across the full range of variation from typical to atypical. The predictive relationships were such that those with poorer performance on inhibition and updating measures were significantly more likely to have a diagnosis of developmental dyslexia and also demonstrate poorer reading ability. These findings suggest that inhibition and updating abilities are associated with developmental dyslexia and predict reading ability. Future studies should explore executive function training as an intervention for children with dyslexia as core executive functions appear to be modifiable with training and may transfer to improved reading ability.

Intrapopulation genome size variation in D. melanogaster reflects life history variation and plasticity.

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Lisa L Ellis

2014-07-01

Full Text Available We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions.

Intrapopulation Genome Size Variation in D. melanogaster Reflects Life History Variation and Plasticity

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Ellis, Lisa L.; Huang, Wen; Quinn, Andrew M.; Ahuja, Astha; Alfrejd, Ben; Gomez, Francisco E.; Hjelmen, Carl E.; Moore, Kristi L.; Mackay, Trudy F. C.; Johnston, J. Spencer; Tarone, Aaron M.

2014-01-01

We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions. PMID:25057905

Temporal variations and trends in loads of commonly used pharmaceuticals to large wastewater treatment plants in Sweden, a case study (Ryaverket)

DEFF Research Database (Denmark)

Paxeus, Nicklas; Bester, Kai; El-taliawy, Haitham

Loads of individual commonly used analgesics (ibuprofen, diclofenac), antibiotics (sulfamethoxazole, trimethoprim), β-blockers (atenolol, metoprolol, sotalol, propranolol) and neuroleptics (carbamazepine, citalopram) to a large scale operating WWTP in Sweden (Ryaverket) were studied by monitoring...

An Ensemble Three-Dimensional Constrained Variational Analysis Method to Derive Large-Scale Forcing Data for Single-Column Models

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Tang, Shuaiqi

Atmospheric vertical velocities and advective tendencies are essential as large-scale forcing data to drive single-column models (SCM), cloud-resolving models (CRM) and large-eddy simulations (LES). They cannot be directly measured or easily calculated with great accuracy from field measurements. In the Atmospheric Radiation Measurement (ARM) program, a constrained variational algorithm (1DCVA) has been used to derive large-scale forcing data over a sounding network domain with the aid of flux measurements at the surface and top of the atmosphere (TOA). We extend the 1DCVA algorithm into three dimensions (3DCVA) along with other improvements to calculate gridded large-scale forcing data. We also introduce an ensemble framework using different background data, error covariance matrices and constraint variables to quantify the uncertainties of the large-scale forcing data. The results of sensitivity study show that the derived forcing data and SCM simulated clouds are more sensitive to the background data than to the error covariance matrices and constraint variables, while horizontal moisture advection has relatively large sensitivities to the precipitation, the dominate constraint variable. Using a mid-latitude cyclone case study in March 3rd, 2000 at the ARM Southern Great Plains (SGP) site, we investigate the spatial distribution of diabatic heating sources (Q1) and moisture sinks (Q2), and show that they are consistent with the satellite clouds and intuitive structure of the mid-latitude cyclone. We also evaluate the Q1 and Q2 in analysis/reanalysis, finding that the regional analysis/reanalysis all tend to underestimate the sub-grid scale upward transport of moist static energy in the lower troposphere. With the uncertainties from large-scale forcing data and observation specified, we compare SCM results and observations and find that models have large biases on cloud properties which could not be fully explained by the uncertainty from the large-scale forcing

System for face recognition under expression variations of neutral-sampled individuals using recognized expression warping and a virtual expression-face database

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Petpairote, Chayanut; Madarasmi, Suthep; Chamnongthai, Kosin

2018-01-01

The practical identification of individuals using facial recognition techniques requires the matching of faces with specific expressions to faces from a neutral face database. A method for facial recognition under varied expressions against neutral face samples of individuals via recognition of expression warping and the use of a virtual expression-face database is proposed. In this method, facial expressions are recognized and the input expression faces are classified into facial expression groups. To aid facial recognition, the virtual expression-face database is sorted into average facial-expression shapes and by coarse- and fine-featured facial textures. Wrinkle information is also employed in classification by using a process of masking to adjust input faces to match the expression-face database. We evaluate the performance of the proposed method using the CMU multi-PIE, Cohn-Kanade, and AR expression-face databases, and we find that it provides significantly improved results in terms of face recognition accuracy compared to conventional methods and is acceptable for facial recognition under expression variation.

Variation in recombination frequency and distribution across eukaryotes: patterns and processes

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Feulner, Philine G. D.; Johnston, Susan E.; Santure, Anna W.; Smadja, Carole M.

2017-01-01

Recombination, the exchange of DNA between maternal and paternal chromosomes during meiosis, is an essential feature of sexual reproduction in nearly all multicellular organisms. While the role of recombination in the evolution of sex has received theoretical and empirical attention, less is known about how recombination rate itself evolves and what influence this has on evolutionary processes within sexually reproducing organisms. Here, we explore the patterns of, and processes governing recombination in eukaryotes. We summarize patterns of variation, integrating current knowledge with an analysis of linkage map data in 353 organisms. We then discuss proximate and ultimate processes governing recombination rate variation and consider how these influence evolutionary processes. Genome-wide recombination rates (cM/Mb) can vary more than tenfold across eukaryotes, and there is large variation in the distribution of recombination events across closely related taxa, populations and individuals. We discuss how variation in rate and distribution relates to genome architecture, genetic and epigenetic mechanisms, sex, environmental perturbations and variable selective pressures. There has been great progress in determining the molecular mechanisms governing recombination, and with the continued development of new modelling and empirical approaches, there is now also great opportunity to further our understanding of how and why recombination rate varies. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’. PMID:29109219

Variational principles in physics

CERN Document Server

Basdevant, Jean-Louis

2007-01-01

Optimization under constraints is an essential part of everyday life. Indeed, we routinely solve problems by striking a balance between contradictory interests, individual desires and material contingencies. This notion of equilibrium was dear to thinkers of the enlightenment, as illustrated by Montesquieu’s famous formulation: "In all magistracies, the greatness of the power must be compensated by the brevity of the duration." Astonishingly, natural laws are guided by a similar principle. Variational principles have proven to be surprisingly fertile. For example, Fermat used variational methods to demonstrate that light follows the fastest route from one point to another, an idea which came to be known as Fermat’s principle, a cornerstone of geometrical optics. Variational Principles in Physics explains variational principles and charts their use throughout modern physics. The heart of the book is devoted to the analytical mechanics of Lagrange and Hamilton, the basic tools of any physicist. Prof. Basdev...

The African Genome Variation Project shapes medical genetics in Africa

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Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.

2014-01-01

Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterisation of African genetic diversity is needed. The African Genome Variation Project (AGVP) provides a resource to help design, implement and interpret genomic studies in sub-Saharan Africa (SSA) and worldwide. The AGVP represents dense genotypes from 1,481 and whole genome sequences (WGS) from 320 individuals across SSA. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across SSA. We identify new loci under selection, including for malaria and hypertension. We show that modern imputation panels can identify association signals at highly differentiated loci across populations in SSA. Using WGS, we show further improvement in imputation accuracy supporting efforts for large-scale sequencing of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa, showing for the first time that such designs are feasible. PMID:25470054

Species conservation and natural variation among populations [Chapter 5

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Leonard F. Ruggiero; Michael K. Schwartz; Keith B. Aubry; Charles J. Krebs; Amanda Stanley; Steven W. Buskirk

2000-01-01

In conservation planning, the importance of natural variation is often given inadequate consideration. However, ignoring the implications of variation within species may result in conservation strategies that jeopardize, rather than conserve, target species (see Grieg 1979; Turcek 1951; Storfer 1999). Natural variation in the traits of individuals and populations is...

Variation in Patients' Travel Times among Imaging Examination Types at a Large Academic Health System.

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Rosenkrantz, Andrew B; Liang, Yu; Duszak, Richard; Recht, Michael P

2017-08-01

Patients' willingness to travel farther distances for certain imaging services may reflect their perceptions of the degree of differentiation of such services. We compare patients' travel times for a range of imaging examinations performed across a large academic health system. We searched the NYU Langone Medical Center Enterprise Data Warehouse to identify 442,990 adult outpatient imaging examinations performed over a recent 3.5-year period. Geocoding software was used to estimate typical driving times from patients' residences to imaging facilities. Variation in travel times was assessed among examination types. The mean expected travel time was 29.2 ± 20.6 minutes, but this varied significantly (p travel times were shortest for ultrasound (26.8 ± 18.9) and longest for positron emission tomography-computed tomography (31.9 ± 21.5). For magnetic resonance imaging, travel times were shortest for musculoskeletal extremity (26.4 ± 19.2) and spine (28.6 ± 21.0) examinations and longest for prostate (35.9 ± 25.6) and breast (32.4 ± 22.3) examinations. For computed tomography, travel times were shortest for a range of screening examinations [colonography (25.5 ± 20.8), coronary artery calcium scoring (26.1 ± 19.2), and lung cancer screening (26.4 ± 14.9)] and longest for angiography (32.0 ± 22.6). For ultrasound, travel times were shortest for aortic aneurysm screening (22.3 ± 18.4) and longest for breast (30.1 ± 19.2) examinations. Overall, men (29.9 ± 21.6) had longer (p travel times than women (27.8 ± 20.3); this difference persisted for each modality individually (p ≤ 0.006). Patients' willingness to travel longer times for certain imaging examination types (particularly breast and prostate imaging) supports the role of specialized services in combating potential commoditization of imaging services. Disparities in travel times by gender warrant further investigation. Copyright �

Unexpectedly high genetic variation in large unisexual clumps of the subdioecious plant Honckenya peploides

DEFF Research Database (Denmark)

Sánchez-Vilas, Julia; Philipp, Marianne; Retuerto, Rubén

2010-01-01

Honckenya peploides is a subdioecious dune plant that reproduces both sexually and by clonal growth. In northwest Spain this species was found to exhibit an extreme spatial segregation of the sexes, and our objective was to investigate genetic variation in unisexual clumps. Genetic variation was ...

Humeral torsion revisited: a functional and ontogenetic model for populational variation.

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Cowgill, Libby W

2007-12-01

Anthropological interest in humeral torsion has a long history, and several functional explanations for observed variation in the orientation of the humeral head have been proposed. Recent clinical studies have revived this topic by linking patterns of humeral torsion to habitual activities such as overhand throwing. However, the precise functional implications and ontogenetic history of humeral torsion remain unclear. This study examines the ontogeny of humeral torsion in a large sample of primarily immature remains from six different skeletal collections (n = 407). The results of this research confirm that humeral torsion displays consistent developmental variation within all populations of growing children; neonates display relatively posteriorly oriented humeral heads, and the level of torsion declines steadily into adulthood. As in adults, variation in the angle of humeral torsion in immature individuals varies by population, and these differences arise early in development. However, when examined in the context of the developing muscles of the shoulder complex, it becomes apparent that variation in the angle of humeral torsion is not necessarily related to specific habitual activities. Variability in this feature is more likely caused by a generalized functional imbalance between muscles of medial and lateral rotation that can be produced by a wide variety of upper limb activity patterns during growth. (c) 2007 Wiley-Liss, Inc.

Regional variation in short distance homogamy

OpenAIRE

Haandrikman, Karen; van Wissen, Leo

2011-01-01

A third of all Dutch cohabiters choose a partner from the same municipality, so-called short distance homogamy. This article analyses the regional variation in this phenomenon, and it explains this variation in terms of geographical, socioeconomic, demographic and cultural determinants. Population register data on all new cohabiters in 2004 were used. Regression methods were employed to explain spatial patterns. Regional variation in short distance homogamy is largely explained by geographica...

Genetic factors for individual administration of immunosuppressants in organ transplantation

Institute of Scientific and Technical Information of China (English)

Song-Feng Yu; Li-Hua Wu; Shu-Sen Zheng

2006-01-01

BACKGROUND: The immunosuppressive drugs used worldwide have a narrow therapeutic index, which results in a need to individualize the dose regimen for different recipients. The oxidative enzymes cytochrome P450 (CYP)3A and the drug eflfux pump P-glycoprotein (P-gp) are two potential factors in the processes of metabolism. Pharmacogenetic study of immunosuppressive drugs has focused on these two enzymes. This review was undertaken to assess the role of single nuclear polymorphisms (SNPs) of these two enzymes in the individual administration of immunosuppressive drugs. DATA SOURCES: An English-language literature search was made using MEDLINE for articles on CYP3A and P-gp in organ transplantation. RESULTS: The SNPs of CYP3A and P-gp are closely correlated to the large variations of cyclosporine and tacrolimus dosage between different patients, although conlficting results were obtained by some authors. CONCLUSIONS: More studies should be conducted to elucidate further the pharmacogenetics of immuno-suppressive drugs in organ transplantation, a deep understanding of which would provide an important step toward drug regimen individualization in the posttransplant therapy.

A global reference for human genetic variation

DEFF Research Database (Denmark)

Auton, Adam; Abecasis, Goncalo R.; M. Altshuler, David

2015-01-01

The 1000 Genomes Project set out to provide a comprehensive description of common human genetic variation by applying whole-genome sequencing to a diverse set of individuals from multiple populations. Here we report completion of the project, having reconstructed the genomes of 2,504 individuals ...

Variations in pollinator density and impacts on large cardamom (Amomum subulatum Roxb. crop yield in Sikkim Himalaya, India

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Kailash S. Gaira

2016-03-01

Full Text Available Large cardamom (Amomum subulatum Roxb., a perennial cash crop, cultivated under an agroforestry system in the eastern Himalaya of India, is well recognized as a pollination-dependent crop. Observations on pollinator abundance in Mamlay watershed of Sikkim Himalaya were collected during the blooming season to evaluate the pollinator abundance across sites and time frames, and impact of pollinator abundance on crop yield from 2010 to 2012. The results revealed that the bumblebees and honeybees are most frequent visitors of large cardamom flowers. The abundance of honeybees, however, varied between sites for the years 2010–2012, while that of bumblebees varied for the years 2011 and 2012. The abundance of honeybees resulted in a variation within time frames for 2010 and 2011, while that of bumblebees varied for 2010 and 2012 (p<0.01. The density of pollinators correlated positively with the number of flowers of the target crop. The impact of pollinator abundance revealed that the increasing bumblebee visitation resulted in a higher yield of the crop (i.e. 17–41 g/plant and the increasing abundance of all bees (21–41 g/plant was significant (p<0.03. Therefore, the study concluded that the large cardamom yield is sensitive to pollinator abundance and there is a need for adopting the best pollinator conservation and management practices toward sustaining the yield of large cardamom.

Tests for the replication of an association between Egfr and natural variation in Drosophila melanogaster wing morphology

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Dodgson James

2005-08-01

Full Text Available Abstract Background Quantitative differences between individuals stem from a combination of genetic and environmental factors, with the heritable variation being shaped by evolutionary forces. Drosophila wing shape has emerged as an attractive system for genetic dissection of multi-dimensional traits. We utilize several experimental genetic methods to validation of the contribution of several polymorphisms in the Epidermal growth factor receptor (Egfr gene to wing shape and size, that were previously mapped in populations of Drosophila melanogaster from North Carolina (NC and California (CA. This re-evaluation utilized different genetic testcrosses to generate heterozygous individuals with a variety of genetic backgrounds as well as sampling of new alleles from Kenyan stocks. Results Only one variant, in the Egfr promoter, had replicable effects in all new experiments. However, expanded genotyping of the initial sample of inbred lines rendered the association non-significant in the CA population, while it persisted in the NC sample, suggesting population specific modification of the quantitative trait nucleotide QTN effect. Conclusion Dissection of quantitative trait variation to the nucleotide level can identify sites with replicable effects as small as one percent of the segregating genetic variation. However, the testcross approach to validate QTNs is both labor intensive and time-consuming, and is probably less useful than resampling of large independent sets of outbred individuals.

Estimating Common Growth Patterns in Juvenile Chinook Salmon (Oncorhynchus tshawytscha from Diverse Genetic Stocks and a Large Spatial Extent.

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Pascale A L Goertler

Full Text Available Life history variation in Pacific salmon (Oncorhynchus spp. supports species resilience to natural disturbances and fishery exploitation. Within salmon species, life-history variation often manifests during freshwater and estuarine rearing, as variation in growth. To date, however, characterizing variability in growth patterns within and among individuals has been difficult via conventional sampling methods because of the inability to obtain repeated size measurements. In this study we related otolith microstructures to growth rates of individual juvenile Chinook salmon (O. tshawytscha from the Columbia River estuary over a two-year period (2010-2012. We used dynamic factor analysis to determine whether there were common patterns in growth rates within juveniles based on their natal region, capture location habitat type, and whether they were wild or of hatchery origin. We identified up to five large-scale trends in juvenile growth rates depending on month and year of capture. We also found that hatchery fish had a narrower range of trend loadings for some capture groups, suggesting that hatchery fish do not express the same breadth of growth variability as wild fish. However, we were unable to resolve a relationship between specific growth patterns and habitat transitions. Our study exemplifies how a relatively new statistical analysis can be applied to dating or aging techniques to summarize individual variation, and characterize aspects of life history diversity.

Analyzing structural variations along strike in a deep-water thrust belt

Science.gov (United States)

Totake, Yukitsugu; Butler, Robert W. H.; Bond, Clare E.; Aziz, Aznan

2018-03-01

We characterize a deep-water fold-thrust arrays imaged by a high-resolution 3D seismic dataset in the offshore NW Borneo, Malaysia, to understand the kinematics behind spatial arrangement of structural variations throughout the fold-thrust system. The seismic volume used covers two sub-parallel fold trains associated with a series of fore-thrusts and back-thrusts. We measured fault heave, shortening value, fold geometries (forelimb dip, interlimb angle and crest depth) along strike in individual fold trains. Heave plot on strike projection allows to identify individual thrust segments showing semi-elliptical to triangular to bimodal patterns, and linkages of these segments. The linkage sites are marked by local minima in cumulative heave. These local heave minima are compensated by additional structures, such as small imbricate thrusts and tight folds indicated by large forelimb dip and small interlimb angle. Complementary profiles of the shortening amount for the two fold trains result in smoother gradient of total shortening across the structures. We interpret this reflects kinematic interaction between two fold-thrust trains. This type of along-strike variation analysis provides comprehensive understanding of a fold-thrust system and may provide an interpretative strategy for inferring the presence of complex multiple faults in less well-imaged parts of seismic volumes.

Mate-finding as an overlooked critical determinant of dispersal variation in sexually-reproducing animals.

Science.gov (United States)

Gilroy, James J; Lockwood, Julie L

2012-01-01

Dispersal is a critically important process in ecology, but robust predictive models of animal dispersal remain elusive. We identify a potentially ubiquitous component of variation in animal dispersal that has been largely overlooked until now: the influence of mate encounters on settlement probability. We use an individual-based model to simulate dispersal in sexually-reproducing organisms that follow a simple set of movement rules based on conspecific encounters, within an environment lacking spatial habitat heterogeneity. We show that dispersal distances vary dramatically with fluctuations in population density in such a model, even in the absence of variation in dispersive traits between individuals. In a simple random-walk model with promiscuous mating, dispersal distributions become increasingly 'fat-tailed' at low population densities due to the increasing scarcity of mates. Similar variation arises in models incorporating territoriality. In a model with polygynous mating, we show that patterns of sex-biased dispersal can even be reversed across a gradient of population density, despite underlying dispersal mechanisms remaining unchanged. We show that some widespread dispersal patterns found in nature (e.g. fat tailed distributions) can arise as a result of demographic variability in the absence of heterogeneity in dispersive traits across the population. This implies that models in which individual dispersal distances are considered to be fixed traits might be unrealistic, as dispersal distances vary widely under a single dispersal mechanism when settlement is influenced by mate encounters. Mechanistic models offer a promising means of advancing our understanding of dispersal in sexually-reproducing organisms.

Variations in the service quality of medical practices.

Science.gov (United States)

Ly, Dan P; Glied, Sherry A

2013-11-01

To examine regional variation in the service quality of physician practices and to assess the association of this variation with the supply and organization of physicians. Secondary analyses of the Community Tracking Study (CTS) household and physician surveys. A total of 40,339 individuals who had seen a primary care physician because of an illness or injury and 17,345 generalist physicians across 4 survey time periods in 60 CTS sites were included. Service quality measures used were lag between making an appointment and seeing a physician, and wait time at the physician's office. Our supply measure was the physician-to-population ratio. Our organizational measure was the percentage of physicians in group practices. Multivariate regressions were performed to examine the relationship between service quality and the supply and organization of physicians. There was substantial variation in the service quality of physician visits across the country. For example, in 2003, the average wait time to see a doctor was 16 minutes in Milwaukee but more than 41 minutes in Miami; the average appointment lag for a sick visit in 2003 was 1.2 days in west-central Alabama but almost 6 days in Northwestern Washington. Service quality was not associated with the primary care physician-to-population ratio and had varying associations with the organization of practices. Cross-site variation in service quality of care in primary care has been large, persistent, and associated with the organization of practices. Areas with higher primary care physician-to-population ratios had longer, not shorter, appointment lags.

Why is seed production so variable among individuals? A ten-year study with oaks reveals the importance of soil environment.

Science.gov (United States)

Pérez-Ramos, Ignacio M; Aponte, Cristina; García, Luis V; Padilla-Díaz, Carmen M; Marañón, Teodoro

2014-01-01

Mast-seeding species exhibit not only a large inter-annual variability in seed production but also considerable variability among individuals within the same year. However, very little is known about the causes and consequences for population dynamics of this potentially large between-individual variability. Here, we quantified seed production over ten consecutive years in two Mediterranean oak species - the deciduous Quercus canariensis and the evergreen Q. suber - that coexist in forests of southern Spain. First, we calibrated likelihood models to identify which abiotic and biotic variables best explain the magnitude (hereafter seed productivity) and temporal variation of seed production at the individual level (hereafter CVi), and infer whether reproductive effort results from the available soil resources for the plant or is primarily determined by selectively favoured strategies. Second, we explored the contribution of between-individual variability in seed production as a potential mechanism of satiation for predispersal seed predators. We found that Q. canariensis trees inhabiting moister and more fertile soils were more productive than those growing in more resource-limited sites. Regarding temporal variation, individuals of the two studied oak species inhabiting these resource-rich environments also exhibited larger values of CVi. Interestingly, we detected a satiating effect on granivorous insects at the tree level in Q. suber, which was evident in those years where between-individual variability in acorn production was higher. These findings suggest that individual seed production (both in terms of seed productivity and inter-annual variability) is strongly dependent on soil resource heterogeneity (at least for one of the two studied oak species) with potential repercussions for recruitment and population dynamics. However, other external factors (such as soil heterogeneity in pathogen abundance) or certain inherent characteristics of the tree might be

Global variations of large megathrust earthquake rupture characteristics

Science.gov (United States)

Kanamori, Hiroo

2018-01-01

Despite the surge of great earthquakes along subduction zones over the last decade and advances in observations and analysis techniques, it remains unclear whether earthquake complexity is primarily controlled by persistent fault properties or by dynamics of the failure process. We introduce the radiated energy enhancement factor (REEF), given by the ratio of an event’s directly measured radiated energy to the calculated minimum radiated energy for a source with the same seismic moment and duration, to quantify the rupture complexity. The REEF measurements for 119 large [moment magnitude (Mw) 7.0 to 9.2] megathrust earthquakes distributed globally show marked systematic regional patterns, suggesting that the rupture complexity is strongly influenced by persistent geological factors. We characterize this as the existence of smooth and rough rupture patches with varying interpatch separation, along with failure dynamics producing triggering interactions that augment the regional influences on large events. We present an improved asperity scenario incorporating both effects and categorize global subduction zones and great earthquakes based on their REEF values and slip patterns. Giant earthquakes rupturing over several hundred kilometers can occur in regions with low-REEF patches and small interpatch spacing, such as for the 1960 Chile, 1964 Alaska, and 2011 Tohoku earthquakes, or in regions with high-REEF patches and large interpatch spacing as in the case for the 2004 Sumatra and 1906 Ecuador-Colombia earthquakes. Thus, combining seismic magnitude Mw and REEF, we provide a quantitative framework to better represent the span of rupture characteristics of great earthquakes and to understand global seismicity. PMID:29750186

Modeling of Individual and Organizational Factors Affecting Traumatic Occupational Injuries Based on the Structural Equation Modeling: A Case Study in Large Construction Industries.

Science.gov (United States)

Mohammadfam, Iraj; Soltanzadeh, Ahmad; Moghimbeigi, Abbas; Akbarzadeh, Mehdi

2016-09-01

Individual and organizational factors are the factors influencing traumatic occupational injuries. The aim of the present study was the short path analysis of the severity of occupational injuries based on individual and organizational factors. The present cross-sectional analytical study was implemented on traumatic occupational injuries within a ten-year timeframe in 13 large Iranian construction industries. Modeling and data analysis were done using the structural equation modeling (SEM) approach and the IBM SPSS AMOS statistical software version 22.0, respectively. The mean age and working experience of the injured workers were 28.03 ± 5.33 and 4.53 ± 3.82 years, respectively. The portions of construction and installation activities of traumatic occupational injuries were 64.4% and 18.1%, respectively. The SEM findings showed that the individual, organizational and accident type factors significantly were considered as effective factors on occupational injuries' severity (P accidents' severity in large construction industries.

Inter-individual variation in nucleotide excision repair pathway is modulated by non-synonymous polymorphisms in ERCC4 and MBD4 genes

Energy Technology Data Exchange (ETDEWEB)

Allione, Alessandra, E-mail: alessandra.allione@hugef-torino.org [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Guarrera, Simonetta; Russo, Alessia [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Ricceri, Fulvio [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Department of Medical Sciences, University of Turin, Via Santena 19, 10126 Turin (Italy); Purohit, Rituraj [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Bioinformatics Division, School of Bio Sciences and Technology, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu (India); Pagnani, Andrea; Rosa, Fabio; Polidoro, Silvia; Voglino, Floriana [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Matullo, Giuseppe [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Department of Medical Sciences, University of Turin, Via Santena 19, 10126 Turin (Italy)

2013-11-15

Highlights: • We reported a large inter-individual variability of NER capacity. • ERCC4 rs1800124 and MBD4 rs10342 nsSNP variants were associated with DNA repair capacity. • DNA–protein interaction analyses showed alteration of binding for ERCC4 and MBD4 variants. • A new possible cross-talk between NER and BER pathways has been reported. - Abstract: Inter-individual differences in DNA repair capacity (DRC) may lead to genome instability and, consequently, modulate individual cancer risk. Among the different DNA repair pathways, nucleotide excision repair (NER) is one of the most versatile, as it can eliminate a wide range of helix-distorting DNA lesions caused by ultraviolet light irradiation and chemical mutagens. We performed a genotype–phenotype correlation study in 122 healthy subjects in order to assess if any associations exist between phenotypic profiles of NER and DNA repair gene single nucleotide polymorphisms (SNPs). Individuals were genotyped for 768 SNPs with a custom Illumina Golden Gate Assay, and peripheral blood mononuclear cells (PBMCs) of the same subjects were tested for a NER comet assay to measure DRC after challenging cells by benzo(a)pyrene diolepoxide (BPDE). We observed a large inter-individual variability of NER capacity, with women showing a statistically significant lower DRC (mean ± SD: 6.68 ± 4.76; p = 0.004) than men (mean ± SD: 8.89 ± 5.20). Moreover, DRC was significantly lower in individuals carrying a variant allele for the ERCC4 rs1800124 non-synonymous SNP (nsSNP) (p = 0.006) and significantly higher in subjects with the variant allele of MBD4 rs2005618 SNP (p = 0.008), in linkage disequilibrium (r{sup 2} = 0.908) with rs10342 nsSNP. Traditional in silico docking approaches on protein–DNA and protein–protein interaction showed that Gly875 variant in ERCC4 (rs1800124) decreases the DNA–protein interaction and that Ser273 and Thr273 variants in MBD4 (rs10342) indicate complete loss of protein�

An investigation into the relationship between thickness variations and manufacturing techniques of mouthguards.

Science.gov (United States)

Farrington, Timothy; Coward, Trevor; Onambele-Pearson, Gladys; Taylor, Rebecca L; Earl, Philip; Winwood, Keith

2016-02-01

The aim of this study was to measure the finished thickness of a single identical 4-mm EVA mouthguard model from a large fabricated sample group and to evaluate the degree of material thinning and variations during the fabrication process. Twenty boxes were distributed to dental technician participants, each containing five duplicated dental models (n = 100), alongside 5 × 4 mm mouthguard blanks and a questionnaire. The mouthguards were measured using electronic callipers (resolution: ±0.01 mm) at three specific points. The five thickest and thinnest mouthguards were examined using a CT scanner to describe the surface typography unique to each mouthguard, highlighting dimensional thinning patterns during the fabrication process. Of the three measurement points, the anterior sulcus point of the mouthguard showed a significant degree of variation (up to 34% coefficient of variation), in finished mouthguard thickness between individuals. The mean thickness of the mouthguards in the anterior region was 1.62 ± 0.38 mm with a range of 0.77-2.80 mm. This variation was also evident in the occlusion and posterior lingual regions but to a lesser extent (up to 12.2% and 9.8% variations, respectively). This study highlights variability in the finished thickness of the mouthguards especially in the anterior sulcus region measurement point, both within and between individuals. At the anterior region measurement point of the mouthguard, the mean thickness was 1.62 mm, equating to an overall material thinning of 59.5% when using a single 4-mm EVA blank. This degree of thinning is comparative to previous single operator research studies. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sensitive plant (Mimosa pudica hiding time depends on individual and state

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Sarah Reed-Guy

2017-07-01

Full Text Available The decisions animals make to adjust their antipredator behavior to rapidly changing conditions have been well studied. Inducible defenses in plants are an antipredator behavior that acts on a longer time scale, but sensitive plants, Mimosa pudica, have a much more rapid antipredator response; they temporarily close their leaves when touched. The time they remain closed is defined as hiding time. We studied hiding time in sensitive plants and found that individual plants differed significantly in their hiding times. We then showed that the effect of individual explained substantial variation in hiding time on a short time scale. Finally, on a longer time scale, individuality persisted but the amount of variation attributed to individual decreased. We hypothesized that variation in plant condition might explain this change. We therefore manipulated sunlight availability and quantified hiding time. When deprived of light for 6 h, sensitive plants significantly shortened their hiding times. But when only half a plant was deprived of light, hiding times on the deprived half and light exposed half were not significantly different. This suggests that overall condition best explains variation in sensitive plant antipredator behavior. Just like in animals, sensitive plant antipredator behavior is condition dependent, and, just like in animals, a substantial amount of the remaining variation is explained by individual differences between plants. Thus, models designed to predict plasticity in animal behavior may be successfully applied to understand behavior in other organisms, including plants.

Curbing variations in packaging process through Six Sigma way in a large-scale food-processing industry

Science.gov (United States)

Desai, Darshak A.; Kotadiya, Parth; Makwana, Nikheel; Patel, Sonalinkumar

2015-03-01

Indian industries need overall operational excellence for sustainable profitability and growth in the present age of global competitiveness. Among different quality and productivity improvement techniques, Six Sigma has emerged as one of the most effective breakthrough improvement strategies. Though Indian industries are exploring this improvement methodology to their advantage and reaping the benefits, not much has been presented and published regarding experience of Six Sigma in the food-processing industries. This paper is an effort to exemplify the application of Six Sigma quality improvement drive to one of the large-scale food-processing sectors in India. The paper discusses the phase wiz implementation of define, measure, analyze, improve, and control (DMAIC) on one of the chronic problems, variations in the weight of milk powder pouch. The paper wraps up with the improvements achieved and projected bottom-line gain to the unit by application of Six Sigma methodology.

Genomic variation in CYP3A4: type, frequencies and potential implications for pharmacogenetic understanding.

OpenAIRE

Creemer, O.

2012-01-01

The human cytochrome P450 3A subfamily metabolises endogenous substances and approximately half of all currently available drugs. There is marked inter-individual variation in hepatic expression of the major adult isoform, CYP3A4; the genetic component of this variability is estimated at 60-90% and, as yet, remains largely uncharacterised. Elucidation of genetic factors determining CYP3A4 activity would permit personalised dose-adjustment in therapies with CYP3A4 drug substrates. CYP3A4 genom...

In the Same Boat? On Metaphor Variation as Mediating the Individual Voice in Organizational Change

Science.gov (United States)

Argaman, Einav

2008-01-01

This paper discusses the notion of metaphor variation, and argues that it may play a significant role as a linguistic tool for positioning the subjects in a given organizational change. More specifically, it is argued that metaphor variation enables the subject to corroborate the organization's centripetal forces on the one hand, and to express…

Spontaneous micronucleus frequencies in human peripheral blood lymphocytes as a screening test for an individual variation in a different population and radiation-induced micronucleus induction

International Nuclear Information System (INIS)

Kang, Chang-Mo; Jeon, Hye-Jeong; Cho, Chul-Koo

2004-01-01

Our studies were to evaluate the role of epigenetic factors in the variation of radiosensitivity on human peripheral blood lymphocytes by measuring the frequencies of micronucleus (MN) from 293 healthy subjects of different population for assessing the radiation health risk in Korea. We analyzed the frequencies of both spontaneous and in vitro 60 Co γ-rays or 50MeV neutron-induced MNs. The frequencies of spontaneous NMs not only vary greatly between individuals, but also working or living areas. The increased levels of cells with spontaneous MNs were observed with an increasing age. The frequencies of spontaneous MNs were significantly higher in females than in males. For both sexes, MN frequency was significantly and positively correlated with age. Age and gender are the most important demographic variables impacting on the MN index. Donors who had ever smoked showed significantly increased frequencies of MNs compared to nonsmokers. The main lifestyle factors influencing the MN index in the subjects are correlated significantly and positively with smoke while measuring the spontaneous frequencies of micronuclei. Therefore, it is evident that with regard to the application of MN assay all future studies to evaluate the association between radiosensitivity and susceptibility for radiation health risks in different populations should take into account the effect of age, gender and lifestyle. For the dose-response study, the induced MNs were observed at all doses, and the numerical changes according to doses. The dose-response curves were fitted with a linear-quadratic forms of the dose, and the results were different for γ-rays and neutrons significantly. Neutrons were more effective than γ-rays in producing MN with a dose-dependent manner. The frequency of MN varies with dose. The RBE for a micronuclei was 2.37 ± 0.17. The results suggested that the MN assay have a high potential to ensure appropriate quality control and a standard documentation protocol, which

Energetic Physiology Mediates Individual Optimization of Breeding Phenology in a Migratory Arctic Seabird.

Science.gov (United States)

Hennin, Holly L; Bêty, Jöel; Legagneux, Pierre; Gilchrist, H Grant; Williams, Tony D; Love, Oliver P

2016-10-01

The influence of variation in individual state on key reproductive decisions impacting fitness is well appreciated in evolutionary ecology. Rowe et al. (1994) developed a condition-dependent individual optimization model predicting that three key factors impact the ability of migratory female birds to individually optimize breeding phenology to maximize fitness in seasonal environments: arrival condition, arrival date, and ability to gain in condition on the breeding grounds. While empirical studies have confirmed that greater arrival body mass and earlier arrival dates result in earlier laying, no study has assessed whether individual variation in energetic management of condition gain effects this key fitness-related decision. Using an 8-year data set from over 350 prebreeding female Arctic common eiders (Somateria mollissima), we tested this component of the model by examining whether individual variation in two physiological traits influencing energetic management (plasma triglycerides: physiological fattening rate; baseline corticosterone: energetic demand) predicted individual variation in breeding phenology after controlling for arrival date and body mass. As predicted by the optimization model, individuals with higher fattening rates and lower energetic demand had the earliest breeding phenology (shortest delays between arrival and laying; earliest laying dates). Our results are the first to empirically determine that individual flexibility in prebreeding energetic management influences key fitness-related reproductive decisions, suggesting that individuals have the capacity to optimally manage reproductive investment.

Individualized Marriage and the Integration of Resources

Science.gov (United States)

Lauer, Sean R.; Yodanis, Carrie

2011-01-01

In individualized marriages, spouses maintain independence in their relationship. In individualized marriages, do married couples manage their money in pooled accounts or do they keep separate accounts? We answer this question with the 2002 International Social Survey Programme (N = 18,587;31 country contexts) and examine how variation in the…

Geographic variation of strontium and hydrogen isotopes in avian tissue: implications for tracking migration and dispersal.

Directory of Open Access Journals (Sweden)

Megan J Sellick

Full Text Available Isotopes can provide unique solutions to fundamental problems related to the ecology and evolution of migration and dispersal because prior movements of individuals can theoretically be tracked from tissues collected from a single capture. However, there is still remarkably little information available about how and why isotopes vary in wild animal tissues, especially over large spatial scales.Here, we describe variation in both stable-hydrogen (deltaD(F and strontium ((87Sr/(86Sr(F isotopic compositions in the feathers of a migratory songbird, the Tree Swallow (Tachycineta bicolor, across 18 sampling sites in North America and then examine potential mechanisms driving this variation. We found that deltaD(F was correlated with latitude of the sampling site, whereas (87Sr/(86Sr(F was correlated with longitude. deltaD(F was related to deltaD of meteoric waters where molting occurred and (87Sr/(86Sr(F was influenced primarily by the geology in the area where feathers were grown. Using simulation models, we then assessed the utility of combining both markers to estimate the origin of individuals. Using 13 geographic regions, we found that the number of individuals correctly assigned to their site of origin increased from less than 40% using either deltaD or (87Sr/(86Sr alone to 74% using both isotopes.Our results suggest that these isotopes have the potential to provide predictable and complementary markers for estimating long-distance animal movements. Combining isotopes influenced by different global-scale processes may allow researchers to link the population dynamics of animals across large geographic ranges.

Anatomical variations of the circle of Willis and cerebrovascular accidents in transitional Albania

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Edlira Harizi (Shemsi

2015-12-01

Full Text Available Aim: The purpose of this study was twofold: i in a case-control design, to determine the relationship between anatomical variations of the circle of Willis and cerebrovascular accidents; ii to assess the association between anatomical variations of the circle of Willis and aneurisms among patients with subarachnoid hemorrhage. Methods: A case-control study was conducted in Albania in 2013-2014, including 100 patients with subarachnoid hemorrhage and 100 controls (individuals without cerebrovascular accidents. Patients with subarachnoid hemorrhage underwent a CT angiography procedure, whereas individuals in the control group underwent a magnetic resonance angiography procedure. Binary logistic regression was used to assess the association between cerebrovascular accidents and the anatomical variations of the circle of Willis. Conversely, Fisher’s exact test was used to compare the prevalence of aneurisms between subarachnoid hemorrhage patients with and without anatomical variations of the circle of Willis. Results: Among patients, there were 22 (22% cases with anatomical variations of the circle of Willis compared with 10 (10% individuals in the control group (P=0.033. There was no evidence of a statistically significant difference in the types of the anatomical variations of the circle of Willis between patients and controls (P=0.402. In age- and-sex adjusted logistic regression models, there was evidence of a significant positive association between cerebrovascular accidents and the anatomical variations of the circle of Willis (OR=1.87, 95%CI=1.03-4.68, P=0.048. Within the patients’ group, of the 52 cases with aneurisms, there were 22 (42.3% individuals with anatomical variations of the circle of Willis compared with no individuals with anatomical variations among the 48 patients without aneurisms (P<0.001. Conclusion: This study provides useful evidence on the association between anatomical variations of the circle of Willis and

Contrasting patterns of leaf trait variation among and within species during tropical dry forest succession in Costa Rica.

Science.gov (United States)

Derroire, Géraldine; Powers, Jennifer S; Hulshof, Catherine M; Cárdenas Varela, Luis E; Healey, John R

2018-01-10

A coordinated response to environmental drivers amongst individual functional traits is central to the plant strategy concept. However, whether the trait co-ordination observed at the global scale occurs at other ecological scales (especially within species) remains an open question. Here, for sapling communities of two tropical dry forest types in Costa Rica, we show large differences amongst traits in the relative contribution of species turnover and intraspecific variation to their directional changes in response to environmental changes along a successional gradient. We studied the response of functional traits associated with the leaf economics spectrum and drought tolerance using intensive sampling to analyse inter- and intra-specific responses to environmental changes and ontogeny. Although the overall functional composition of the sapling communities changed during succession more through species turnover than through intraspecific trait variation, their relative contributions differed greatly amongst traits. For instance, community mean specific leaf area changed mostly due to intraspecific variation. Traits of the leaf economics spectrum showed decoupled responses to environmental drivers and ontogeny. These findings emphasise how divergent ecological mechanisms combine to cause great differences in changes of individual functional traits over environmental gradients and ecological scales.

Variation in chick-a-dee calls of tufted titmice, Baeolophus bicolor: note type and individual distinctiveness.

Science.gov (United States)

Owens, Jessica L; Freeberg, Todd M

2007-08-01

The chick-a-dee call of chickadee species (genus Poecile) has been the focus of much research. A great deal is known about the structural complexity and the meaning of variation in notes making up calls in these species. However, little is known about the likely homologous "chick-a-dee" call of the closely related tufted titmouse, Baeolophus bicolor. Tufted titmice are a prime candidate for comparative analyses of the call, because their vocal and social systems share many characteristics with those of chickadees. To address the paucity of data on the structure of chick-a-dee calls of tufted titmice, we recorded birds in field and aviary settings. Four main note types were identified in the call: Z, A, D(h), and D notes. Several acoustic parameters of each note type were measured, and statistical analyses revealed that the note types are acoustically distinct from one another. Furthermore, note types vary in the extent of individual distinctiveness reflected in their acoustic parameters. This first step towards understanding the chick-a-dee call of tufted titmice indicates that the call is comparable in structure and complexity to the calls of chickadees.

Explaining growth variation over large spatial scales: Effects of temperature and food on walleye growth

DEFF Research Database (Denmark)

Mosgaard, Thomas; Venturelli, Paul; Lester, Nigel P.

2012-01-01

freshwater fish species in North America. We then use length at age data from yellow perch (Perca flavescens) to identify the mechanisms behind the remaining variation in the length at age – temperature relationship for walleye. A positive perch – walleye relationship indicates that the mechanism behind......Most fishes exhibit strong spatial variation in growth. Because fish growth and production are tightly linked, quantifying and explaining variation in growth can mean the difference between successful management and unforeseen collapse. However, disentangling the factors that are responsible...

Patient dose variation investigated in four Irish hospitals for barium meal and barium enema examinations

International Nuclear Information System (INIS)

Carroll, E.; Brennan, P.C.

2001-01-01

Four hospitals have been studied, intra- and inter-hospital variations examined and the mean DAP values recorded for barium enemas and barium meals. Mean DAP values for barium meals and barium enemas at 11.4 Gy.cm 2 and 20.1 Gy.cm 2 respectively have been shown. Differences between individual examinations for barium meals varied by up to a factor of 185 and for barium enemas, up to a factor of 19, with hospital means for barium meal and enema examinations each differing by up to a factor of 3. The data provided by this study have suggested that large variations in patient dose do exist in Ireland for barium meal and barium enema examinations. Fluoroscopy time was shown to be a major contributor to the variations reported, with number of images playing a minor role. Results have demonstrated the need for standardisation of technique throughout the country for these examinations. (author)

Geographic variation and effect of area-level poverty rate on colorectal cancer screening.

Science.gov (United States)

Lian, Min; Schootman, Mario; Yun, Shumei

2008-10-16

With a secular trend of increasing colorectal cancer (CRC) screening, concerns about disparities in CRC screening also have been rising. It is unclear if CRC screening varies geographically, if area-level poverty rate affects CRC screening, and if individual-level characteristics mediate the area-level effects on CRC screening. Using 2006 Missouri Behavioral Risk Factor Surveillance System (BRFSS) data, a multilevel study was conducted to examine geographic variation and the effect of area-level poverty rate on CRC screening use among persons age 50 or older. Individuals were nested within ZIP codes (ZIP5 areas), which in turn, were nested within aggregations of ZIP codes (ZIP3 areas). Six groups of individual-level covariates were considered as potential mediators. An estimated 51.8% of Missourians aged 50 or older adhered to CRC screening recommendations. Nearly 15% of the total variation in CRC screening lay between ZIP5 areas. Persons residing in ZIP5 areas with > or = 10% of poverty rate had lower odds of CRC screening use than those residing in ZIP5 areas with poverty rate (unadjusted odds ratio [OR], 0.69; 95% confidence interval [95% CI], 0.58-0.81; adjusted OR, 0.81; 95% CI, 0.67-0.98). Persons who resided in ZIP3 areas with > or = 20% poverty rate also had lower odds of following CRC screening guidelines than those residing in ZIP3 areas with poverty rate (unadjusted OR, 0.66; 95% CI, 0.52-0.83; adjusted OR, 0.64; 95% CI, 0.50-0.83). Obesity, history of depression/anxiety and access to care were associated with CRC screening, but did not mediate the effect of area-level poverty on CRC screening. Large geographic variation of CRC screening exists in Missouri. Area-level poverty rate, independent of individual-level characteristics, is a significant predictor of CRC screening, but it only explains a small portion of the geographic heterogeneity of CRC screening. Individual-level factors we examined do not mediate the effect of the area-level poverty rate on

Inter-doctor variations in the assessment of functional incapacities by insurance physicians

Directory of Open Access Journals (Sweden)

Schellart Antonius JM

2011-11-01

Full Text Available Abstract Background The aim of this study was to determine the - largely unexplored - extent of systematic variation in the work disability assessment by Dutch insurance physicians (IPs of employees on long-term sick leave, and to ascertain whether this variation was associated with the individual characteristics and opinions of IPs. Methods In March 2008 we conducted a survey among IPs on the basis of the 'Attitude - Social norm - self-Efficacy' (ASE model. We used the ensuing data to form latent variables for the ASE constructs. We then linked the background variables and the measured constructs for IPs (n = 199 working at regional offices (n = 27 to the work disability assessments of clients (n = 83,755 and their characteristics. These assessments were carried out between July 2003 and April 2008. We performed multilevel regression analysis on three important assessment outcomes: No Sustainable Capacity or Restrictions for Working Hours (binominal, Functional Incapacity Score (scale 0-6 and Maximum Work Disability Class (binominal. We calculated Intra Class Correlations (ICCs at IP level and office level and explained variances (R2 for the three outcomes. A higher ICC reflects stronger systematic variation. Results The ICCs at IP level were approximately 6% for No Sustainable Capacity or Restrictions for Working Hours and Maximum Work Disability Class and 12% for Functional Incapacity Score. Background IP variables and the measured ASE constructs for physicians contributed very little to the variation - at most 1%. The ICCs at office level ranged from 0% to around 1%. The R2 was 11% for No Sustainable Capacity or Restrictions for Working Hours, 19% for Functional Incapacity Score and 37% for Maximum Work Disability Class. Conclusion Our study uncovered small to moderate systematic variations in the outcome of disability assessments in the Netherlands. However, the individual characteristics and opinions of insurance physicians have very

Large Torque Variations in Two Soft Gamma Repeaters

NARCIS (Netherlands)

Woods, P.M.; Kouveliotou, C.; Göğüş, E.; Finger, M.H.; Swank, J.; Markwardt, C.B.; Hurley, K.; van der Klis, M.

2002-01-01

We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-Ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor

Genetic analysis of variation in human meiotic recombination.

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Reshmi Chowdhury

2009-09-01

Full Text Available The number of recombination events per meiosis varies extensively among individuals. This recombination phenotype differs between female and male, and also among individuals of each gender. In this study, we used high-density SNP genotypes of over 2,300 individuals and their offspring in two datasets to characterize recombination landscape and to map the genetic variants that contribute to variation in recombination phenotypes. We found six genetic loci that are associated with recombination phenotypes. Two of these (RNF212 and an inversion on chromosome 17q21.31 were previously reported in the Icelandic population, and this is the first replication in any other population. Of the four newly identified loci (KIAA1462, PDZK1, UGCG, NUB1, results from expression studies provide support for their roles in meiosis. Each of the variants that we identified explains only a small fraction of the individual variation in recombination. Notably, we found different sequence variants associated with female and male recombination phenotypes, suggesting that they are regulated by different genes. Characterization of genetic variants that influence natural variation in meiotic recombination will lead to a better understanding of normal meiotic events as well as of non-disjunction, the primary cause of pregnancy loss.

Variation, structure and norms

DEFF Research Database (Denmark)

Harder, Peter

2014-01-01

in linguistics: those that see linguistic norms as antithetical to a descriptive and variational linguistics. Once such a re-evaluation has taken place, however, the social recontextualization of cognition will enable linguistics (including sociolinguistics as an integral part), to eliminate the cracks...... that an evolutionary account can reintegrate the opposed fragments into a whole picture that puts each of them in their ‘ecological position’ with respect to each other. Empirical usage facts should be seen in the context of operational norms in relation to which actual linguistic choices represent adaptations....... Variational patterns should be seen in the context of structural categories without which there would be only ‘differences’ rather than variation. And emergence, individual choice, and flux should be seen in the context of the individual’s dependence on lineages of community practice sustained by collective...

The global role of health care delivery science: learning from variation to build health systems that avoid waste and harm.

Science.gov (United States)

Mulley, Albert G

2013-09-01

This paper addresses the fourth theme of the Indiana Global Health Research Working Conference, Clinical Effectiveness and Health Systems Research. It explores geographic variation in health care delivery and health outcomes as a source of learning how to achieve better health outcomes at lower cost. It focuses particularly on the relationship between investments made in capacities to deliver different health care services to a population and the value thereby created by that care for individual patients. The framing begins with the dramatic variation in per capita health care expenditures across the nations of the world, which is largely explained by variations in national wealth. The 1978 Declaration of Alma Ata is briefly noted as a response to such inequities with great promise that has not as yet been realized. This failure to realize the promise of Alma Ata grows in significance with the increasing momentum for universal health coverage that is emerging in the current global debate about post-2015 development goals. Drawing upon work done at Dartmouth over more than three decades, the framing then turns to within-country variations in per capita expenditures, utilization of different services, and health outcomes. A case is made for greater attention to the question of value by bringing better information to bear at both the population and individual levels. Specific opportunities to identify and reduce waste in health care, and the harm that is so often associated with it, are identified by learning from outcome variations and practice variations.

Individual and contextual variation in Thomas langur male loud calls

NARCIS (Netherlands)

Wich, S.A.; Koski, S.; Vries, Han de; Schaik, Carel P. van

2003-01-01

Individual and contextual differences in male loud calls of wild Thomas langurs (Presbytis thomasi) were studied in northern Sumatra, Indonesia. Loud calls were given in the following contexts: morning calls, vocal responses to other groups, between-group encounter calls and alarmcalls. Loud

Isogeometric variational multiscale large-eddy simulation of fully-developed turbulent flow over a wavy wall

KAUST Repository

Chang, Kyungsik; Hughes, Thomas Jr R; Calo, Victor M.

2012-01-01

We report on the isogeometric residual-based variational multiscale (VMS) large eddy simulation of a fully developed turbulent flow over a wavy wall. To assess the predictive capability of the VMS modeling framework, we compare its predictions against the results from direct numerical simulation (DNS) and large eddy simulation (LES) and, when available, against experimental measurements. We use C 1 quadratic B-spline basis functions to represent the smooth geometry of the sinusoidal lower wall and the solution variables. The Reynolds numbers of the flows considered are 6760 and 30,000 based on the bulk velocity and average channel height. The ratio of amplitude to wavelength (α/λ) of the sinusoidal wavy surface is set to 0.05. The computational domain is 2λ×1.05λ×λ in the streamwise, wall-normal and spanwise directions, respectively. For the Re=6760 case, mean averaged quantities, including velocity and pressure profiles, and the separation/reattachment points in the recirculation region, are compared with DNS and experimental data. The turbulent kinetic energy and Reynolds stress are in good agreement with benchmark data. Coherent structures over the wavy wall are observed in isosurfaces of the Q-criterion and show similar features to those previously reported in the literature. Comparable accuracy to DNS solutions is obtained with at least one order of magnitude fewer degrees of freedom. For the Re=30,000 case, good agreement was obtained for mean wall shear stress and velocity profiles compared with available LES results reported in the literature. © 2012 Elsevier Ltd.

Isogeometric variational multiscale large-eddy simulation of fully-developed turbulent flow over a wavy wall

KAUST Repository

Chang, Kyungsik

2012-09-01

We report on the isogeometric residual-based variational multiscale (VMS) large eddy simulation of a fully developed turbulent flow over a wavy wall. To assess the predictive capability of the VMS modeling framework, we compare its predictions against the results from direct numerical simulation (DNS) and large eddy simulation (LES) and, when available, against experimental measurements. We use C 1 quadratic B-spline basis functions to represent the smooth geometry of the sinusoidal lower wall and the solution variables. The Reynolds numbers of the flows considered are 6760 and 30,000 based on the bulk velocity and average channel height. The ratio of amplitude to wavelength (α/λ) of the sinusoidal wavy surface is set to 0.05. The computational domain is 2λ×1.05λ×λ in the streamwise, wall-normal and spanwise directions, respectively. For the Re=6760 case, mean averaged quantities, including velocity and pressure profiles, and the separation/reattachment points in the recirculation region, are compared with DNS and experimental data. The turbulent kinetic energy and Reynolds stress are in good agreement with benchmark data. Coherent structures over the wavy wall are observed in isosurfaces of the Q-criterion and show similar features to those previously reported in the literature. Comparable accuracy to DNS solutions is obtained with at least one order of magnitude fewer degrees of freedom. For the Re=30,000 case, good agreement was obtained for mean wall shear stress and velocity profiles compared with available LES results reported in the literature. © 2012 Elsevier Ltd.

A study of diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India

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Jenny Jayapal

2014-01-01

Full Text Available Background: Peak Expiratory Flow Rate (PEFR reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. PEFR shows hour to hour variation that follows a specific pattern in asthmatics and healthy individuals. Adequate data is not available for the diurnal variation in normal individuals who are students in professional courses and had a sedentary life style. Hence, this study was undertaken to study the diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India. Materials and Methods: Peak expiratory flow rate was recorded in 50 adult healthy female students aged 18-23 years and studying in professional courses. Mini Wright′s peak flow meter was used to measure the peak expiratory flow rate. PEFR were recorded at 7-8 a.m., 10-11 a.m., 1-2 p.m., 4-5 p.m., and 7-8 p.m. for two consecutive days. Results: On analysis of PEFR records of individual subjects, it was seen that there was an overall dip in the morning at 7-8 h PEFR, which increased in the daytime, peaking in the afternoon at 1-2 p.m. and eventually decreased in the night. Subjects did not show the peak PEFR values at the same time point, 10% of subjects had a rise in PEFR in the early morning, afternoon (1-2 p.m. peak was observed in 48% subjects and evening (4-5 p.m. peak was observed in 16% subjects. 14% subjects showed a peak in the night time (7-8 p.m. PEFR values. Conclusion: This study provided the preliminary reference data of diurnal variation of peak expiratory flow rate in healthy adults. Since, there is a variation in the peak expiratory flow rate recorded during different time points of the day; hence, to compare the PEFR between individuals it is advisable to record the PEFR at the same time point.

Large variations in diurnal and seasonal patterns of sap flux among Aleppo pine trees in semi-arid forest reflect tree-scale hydraulic adjustments

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Preisler, Yakir; Tatarinov, Fyodor; Rohatyn, Shani; Rotenberg, Eyal; Grünzweig, José M.; Klein, Tamir; Yakir, Dan

2015-04-01

Adjustments and adaptations of trees to drought vary across different biomes, species and habitats, with important implications for tree mortality and forest dieback associated with global climate change. The aim of this study was to investigate possible links between the patterns of variations in water flux dynamics and drought resistance in Aleppo pine (Pinus halepensis) trees in a semi-arid stand (Yatir forest, Israel). We measured sap flow (SF) and variations in stem diameter, complemented with short-term campaigns of leaf-scale measurements of water vapour and CO2 gas exchange, branch water potential and hydraulic conductivity, as well as eddy flux measurements of evapotranspiration (ET) from a permanent flux tower at the site. SF rates were well synchronized with ET, reaching maximum rates during midday in all trees during the rainy season (Dec-Apr). However, during the dry season (May-Nov), the daily trend in the rates of SF greatly varied among trees, allowing classification into three tree classes: 1) trees with SF maximum rate constantly occurring in mid-day (12:00-13:00); 2)trees showing a shift to an early morning SF peak (04:00-06:00); and 3) trees shifting their daily SF peak to the evening (16:00-18:00). This classification did not change during the four years study period, between 2010 and 2014. Checking for correlation of tree parameters as DBH, tree height, crown size, and competition indices with rates of SF, indicated that timing of maximum SF in summer was mainly related to tree size (DBH), when large trees tended to have a later SF maximum. Dendrometer measurements indicated that large trees (high DBH) had maximum daily diameter in the morning during summer and winter, while small trees typically had maximum daily diameter during midday and afternoon in winter and summer, respectively. Leaf-scale transpiration (T) measurements showed typical morning peak in all trees, and another peak in the afternoon in large trees only. Different diurnal

Genome Wide Distributions and Functional Characterization of Copy Number Variations between Chinese and Western Pigs.

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Hongyang Wang

Full Text Available Copy number variations (CNVs refer to large insertions, deletions and duplications in the genomic structure ranging from one thousand to several million bases in size. Since the development of next generation sequencing technology, several methods have been well built for detection of copy number variations with high credibility and accuracy. Evidence has shown that CNV occurring in gene region could lead to phenotypic changes due to the alteration in gene structure and dosage. However, it still remains unexplored whether CNVs underlie the phenotypic differences between Chinese and Western domestic pigs. Based on the read-depth methods, we investigated copy number variations using 49 individuals derived from both Chinese and Western pig breeds. A total of 3,131 copy number variation regions (CNVRs were identified with an average size of 13.4 Kb in all individuals during domestication, harboring 1,363 genes. Among them, 129 and 147 CNVRs were Chinese and Western pig specific, respectively. Gene functional enrichments revealed that these CNVRs contribute to strong disease resistance and high prolificacy in Chinese domestic pigs, but strong muscle tissue development in Western domestic pigs. This finding is strongly consistent with the morphologic characteristics of Chinese and Western pigs, indicating that these group-specific CNVRs might have been preserved by artificial selection for the favored phenotypes during independent domestication of Chinese and Western pigs. In this study, we built high-resolution CNV maps in several domestic pig breeds and discovered the group specific CNVs by comparing Chinese and Western pigs, which could provide new insight into genomic variations during pigs' independent domestication, and facilitate further functional studies of CNV-associated genes.

Size variation in Middle Pleistocene humans.

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Arsuaga, J L; Carretero, J M; Lorenzo, C; Gracia, A; Martínez, I; Bermúdez de Castro, J M; Carbonell, E

1997-08-22

It has been suggested that European Middle Pleistocene humans, Neandertals, and prehistoric modern humans had a greater sexual dimorphism than modern humans. Analysis of body size variation and cranial capacity variation in the large sample from the Sima de los Huesos site in Spain showed instead that the sexual dimorphism is comparable in Middle Pleistocene and modern populations.

Effect of laying sequence on egg mercury in captive zebra finches: an interpretation considering individual variation.

Science.gov (United States)

Ou, Langbo; Varian-Ramos, Claire W; Cristol, Daniel A

2015-08-01

Bird eggs are used widely as noninvasive bioindicators for environmental mercury availability. Previous studies, however, have found varying relationships between laying sequence and egg mercury concentrations. Some studies have reported that the mercury concentration was higher in first-laid eggs or declined across the laying sequence, whereas in other studies mercury concentration was not related to egg order. Approximately 300 eggs (61 clutches) were collected from captive zebra finches dosed throughout their reproductive lives with methylmercury (0.3 μg/g, 0.6 μg/g, 1.2 μg/g, or 2.4 μg/g wet wt in diet); the total mercury concentration (mean ± standard deviation [SD] dry wt basis) of their eggs was 7.03 ± 1.38 μg/g, 14.15 ± 2.52 μg/g, 26.85 ± 5.85 μg/g, and 49.76 ± 10.37 μg/g, respectively (equivalent to fresh wt egg mercury concentrations of 1.24 μg/g, 2.50 μg/g, 4.74 μg/g, and 8.79 μg/g). The authors observed a significant decrease in the mercury concentration of successive eggs when compared with the first egg and notable variation between clutches within treatments. The mercury level of individual females within and among treatments did not alter this relationship. Based on the results, sampling of a single egg in each clutch from any position in the laying sequence is sufficient for purposes of population risk assessment, but it is not recommended as a proxy for individual female exposure or as an estimate of average mercury level within the clutch. © 2015 SETAC.

Epigenetic variation predicts regional and local intraspecific functional diversity in a perennial herb.

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Medrano, Mónica; Herrera, Carlos M; Bazaga, Pilar

2014-10-01

The ecological significance of epigenetic variation has been generally inferred from studies on model plants under artificial conditions, but the importance of epigenetic differences between individuals as a source of intraspecific diversity in natural plant populations remains essentially unknown. This study investigates the relationship between epigenetic variation and functional plant diversity by conducting epigenetic (methylation-sensitive amplified fragment length polymorphisms, MSAP) and genetic (amplified fragment length polymorphisms, AFLP) marker-trait association analyses for 20 whole-plant, leaf and regenerative functional traits in a large sample of wild-growing plants of the perennial herb Helleborus foetidus from ten sampling sites in south-eastern Spain. Plants differed widely in functional characteristics, and exhibited greater epigenetic than genetic diversity, as shown by per cent polymorphism of MSAP fragments (92%) or markers (69%) greatly exceeding that for AFLP ones (41%). After controlling for genetic structuring and possible cryptic relatedness, every functional trait considered exhibited a significant association with at least one AFLP or MSAP marker. A total of 27 MSAP (13.0% of total) and 12 AFLP (4.4%) markers were involved in significant associations, which explained on average 8.2% and 8.0% of trait variance, respectively. Individual MSAP markers were more likely to be associated with functional traits than AFLP markers. Between-site differences in multivariate functional diversity were directly related to variation in multilocus epigenetic diversity after multilocus genetic diversity was statistically accounted for. Results suggest that epigenetic variation can be an important source of intraspecific functional diversity in H. foetidus, possibly endowing this species with the capacity to exploit a broad range of ecological conditions despite its modest genetic diversity. © 2014 John Wiley & Sons Ltd.

Identify and Quantify the Mechanistic Sources of Sensor Performance Variation Between Individual Sensors SN1 and SN2

Energy Technology Data Exchange (ETDEWEB)

Diaz, Aaron A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baldwin, David L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cinson, Anthony D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Anthony M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Larche, Michael R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mathews, Royce [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mullen, Crystal A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pardini, Allan F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Posakony, Gerald J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Prowant, Matthew S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hartman, Trenton S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Edwards, Matthew K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-08-06

This Technical Letter Report satisfies the M3AR-14PN2301022 milestone, and is focused on identifying and quantifying the mechanistic sources of sensor performance variation between individual 22-element, linear phased-array sensor prototypes, SN1 and SN2. This effort constitutes an iterative evolution that supports the longer term goal of producing and demonstrating a pre-manufacturing prototype ultrasonic probe that possesses the fundamental performance characteristics necessary to enable the development of a high-temperature sodium-cooled fast reactor inspection system. The scope of the work for this portion of the PNNL effort conducted in FY14 includes performing a comparative evaluation and assessment of the performance characteristics of the SN1 and SN2 22 element PA-UT probes manufactured at PNNL. Key transducer performance parameters, such as sound field dimensions, resolution capabilities, frequency response, and bandwidth are used as a metric for the comparative evaluation and assessment of the SN1 and SN2 engineering test units.

Variations in Branching Pattern of Renal Artery in Kidney Donors Using CT Angiography.

Science.gov (United States)

Munnusamy, Kumaresan; Kasirajan, Sankaran Ponnusamy; Gurusamy, Karthikeyan; Raghunath, Gunapriya; Bolshetty, Shilpakala Leshappa; Chakrabarti, Sudakshina; Annadurai, Priyadarshini; Miyajan, Zareena Begum

2016-03-01

Each kidney is supplied by a single renal artery originating from abdominal aorta. Since there are lots of renal surgeries happening now-a-days, it becomes mandatory for the surgeons to understand the abnormality and variations in the renal vasculature. To study the variations in the branching pattern of renal artery for the presence of early division and accessory renal artery in Indian kidney donors using CT angiography. The CT angiogram images of 100 normal individuals willing for kidney donation were analysed for early divisions and occurrence of accessory renal artery. A 51% of kidney donors showed variation in the renal artery. Out of 51% variations 38 individuals had accessory renal artery and 13 individuals had early division of renal artery. The distribution of accessory renal artery was equal on both sides (13% on right and left) and 12% of individuals had accessory renal artery on both sides. Out of 13% earlier divisions, 5% was on right side, 7% was on left side and 1% was on both sides. This study concludes that 51% of kidney donors had renal artery variations. Hence, awareness of variations by evaluating the donors is a must before renal transplantation, urological procedures and angiographic interventions.

When intensions do not map onto extensions: Individual differences in conceptualization.

Science.gov (United States)

Hampton, James A; Passanisi, Alessia

2016-04-01

Concepts are represented in the mind through knowledge of their extensions (the class of items to which the concept applies) and intensions (features that distinguish that class of items). A common assumption among theories of concepts is that the 2 aspects are intimately related. Hence if there is systematic individual variation in concept representation, the variation should correlate between extensional and intensional measures. A pair of individuals with similar extensional beliefs about a given concept should also share similar intensional beliefs. To test this notion, exemplars (extensions) and features (intensions) of common categories were rated for typicality and importance respectively across 2 occasions. Within-subject consistency was greater than between-subjects consensus on each task, providing evidence for systematic individual variation. Furthermore, the similarity structure between individuals for each task was stable across occasions. However, across 5 samples, similarity between individuals for extensional judgments did not map onto similarity between individuals for intensional judgments. The results challenge the assumption common to many theories of conceptual representation that intensions determine extensions and support a hybrid view of concepts where there is a disconnection between the conceptual resources that are used for the 2 tasks. (c) 2016 APA, all rights reserved).

Seed predators exert selection on the subindividual variation of seed size.

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Sobral, M; Guitián, J; Guitián, P; Larrinaga, A R

2014-07-01

Subindividual variation among repeated organs in plants constitutes an overlooked level of variation in phenotypic selection studies, despite being a major component of phenotypic variation. Animals that interact with plants could be selective agents on subindividual variation. This study examines selective pressures exerted during post-dispersal seed predation and germination on the subindividual variation of seed size in hawthorn (Crataegus monogyna). With a seed offering experiment and a germination test, we estimated phenotypic selection differentials for average and subindividual variation of seed size due to seed predation and germination. Seed size affects germination, growth rate and the probability of an individual seed of escaping predation. Longer seeds showed higher germination rates, but this did not result in significant selection on phenotypes of the maternal trees. On the other hand, seed predators avoided wider seeds, and by doing so exerted phenotypic selection on adult average and subindividual variation of seed size. The detected selection on subindividual variation suggests that the levels of phenotypic variation within individual plants may be, at least partly, the adaptive consequence of animal-mediated selection. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

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

Science.gov (United States)

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

2018-01-01

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

Relationships among and variation within rare breeds of swine.

Science.gov (United States)

Roberts, K S; Lamberson, W R

2015-08-01

Extinction of rare breeds of livestock threatens to reduce the total genetic variation available for selection in the face of the changing environment and new diseases. Swine breeds facing extinction typically share characteristics such as small size, slow growth rate, and high fat percentage, which limit them from contributing to commercial production. Compounding the risk of loss of variation is the lack of pedigree information for many rare breeds due to inadequate herd books, which increases the chance that producers are breeding closely related individuals. By making genetic data available, producers can make more educated breeding decisions to preserve genetic diversity in future generations, and conservation organizations can prioritize investments in breed preservation. The objective of this study was to characterize genetic variation within and among breeds of swine and prioritize heritage breeds for preservation. Genotypes from the Illumina PorcineSNP60 BeadChip (GeneSeek, Lincoln, NE) were obtained for Guinea, Ossabaw Island, Red Wattle, American Saddleback, Mulefoot, British Saddleback, Duroc, Landrace, Large White, Pietrain, and Tamworth pigs. A whole-genome analysis toolset was used to construct a genomic relationship matrix and to calculate inbreeding coefficients for the animals within each breed. Relatedness and average inbreeding coefficient differed among breeds, and pigs from rare breeds were generally more closely related and more inbred ( Guinea pigs. Tamworth, Duroc, and Mulefoot tended to not cluster with the other 7 breeds.

Solution of problems in calculus of variations via He's variational iteration method

International Nuclear Information System (INIS)

Tatari, Mehdi; Dehghan, Mehdi

2007-01-01

In the modeling of a large class of problems in science and engineering, the minimization of a functional is appeared. Finding the solution of these problems needs to solve the corresponding ordinary differential equations which are generally nonlinear. In recent years He's variational iteration method has been attracted a lot of attention of the researchers for solving nonlinear problems. This method finds the solution of the problem without any discretization of the equation. Since this method gives a closed form solution of the problem and avoids the round off errors, it can be considered as an efficient method for solving various kinds of problems. In this research He's variational iteration method will be employed for solving some problems in calculus of variations. Some examples are presented to show the efficiency of the proposed technique

A comparison of vowel normalization procedures for language variation research

Science.gov (United States)

Adank, Patti; Smits, Roel; van Hout, Roeland

2004-11-01

An evaluation of vowel normalization procedures for the purpose of studying language variation is presented. The procedures were compared on how effectively they (a) preserve phonemic information, (b) preserve information about the talker's regional background (or sociolinguistic information), and (c) minimize anatomical/physiological variation in acoustic representations of vowels. Recordings were made for 80 female talkers and 80 male talkers of Dutch. These talkers were stratified according to their gender and regional background. The normalization procedures were applied to measurements of the fundamental frequency and the first three formant frequencies for a large set of vowel tokens. The normalization procedures were evaluated through statistical pattern analysis. The results show that normalization procedures that use information across multiple vowels (``vowel-extrinsic'' information) to normalize a single vowel token performed better than those that include only information contained in the vowel token itself (``vowel-intrinsic'' information). Furthermore, the results show that normalization procedures that operate on individual formants performed better than those that use information across multiple formants (e.g., ``formant-extrinsic'' F2-F1). .

Morphological variations of hippocampal formation in epilepsy: image, clinical and electrophysiological data.

Science.gov (United States)

Hamad, Ana Paula Andrade; Carrete, Henrique; Bianchin, Marino Muxfeldt; Ferrari-Marinho, Taissa; Lin, Katia; Yacubian, Elza Márcia Targas; Vilanova, Luiz Celso Pereira; Garzon, Eliana; Caboclo, Luís Otávio; Sakamoto, Américo Ceiki

2013-01-01

Morphological variations of hippocampal formation (MVHF) are observed in patients with epilepsy but also in asymptomatic individuals. The precise role of these findings in epilepsy is not yet fully understood. This study analyzes the hippocampal formation (HF) morphology of asymptomatic individuals (n = 30) and of patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) (n = 68), patients with malformations of cortical development (MCD) (n = 34), or patients with pure morphological variations of hippocampal formation (pure MVHF) (n = 12). Main clinical and electrophysiological data of patients with MVHF were also analyzed. Morphological variations of hippocampal formation are more frequently observed in patients with MCD than in patients with MTLE-HS or in asymptomatic individuals. Patients with pure morphological variations of hippocampal formation showed higher incidence of extratemporal seizure onset. Refractoriness seems to be more associated with other abnormalities, like HS or MCD, than with the HF variation itself. Thus, although morphological HF abnormalities might play a role in epileptogenicity, they seem to contribute less to refractoriness. Copyright © 2012 Elsevier Inc. All rights reserved.

Asymptotic Behaviour of Total Generalised Variation

KAUST Repository

Papafitsoros, Konstantinos; Valkonen, Tuomo

2015-01-01

© Springer International Publishing Switzerland 2015. The recently introduced second order total generalised variation functional TGV2 β,α has been a successful regulariser for image processing purposes. Its definition involves two positive parameters α and β whose values determine the amount and the quality of the regularisation. In this paper we report on the behaviour of TGV2 β,α in the cases where the parameters α, β as well as their ratio β/α becomes very large or very small. Among others, we prove that for sufficiently symmetric two dimensional data and large ratio β/α, TGV2 β,α regularisation coincides with total variation (TV) regularization

Analysis of cyclic variations of liquid fuel-air mixing processes in a realistic DISI IC-engine using Large Eddy Simulation

International Nuclear Information System (INIS)

Goryntsev, D.; Sadiki, A.; Klein, M.; Janicka, J.

2010-01-01

Direct injection spark ignition (DISI) engines have a large potential to reduce emissions and specific fuel consumption. One of the most important problem in the design of DISI engines is the cycle-to-cycle variations of the flow, mixing and combustion processes. The Large Eddy Simulation (LES) based analysis is used to characterize the cycle-to-cycle fluctuations of the flow field as well as the mixture preparation in a realistic four-stroke internal combustion engine with variable charge motion system. Based on the analysis of cycle-to-cycle velocity fluctuations of in-cylinder flow, the impact of various fuel spray boundary conditions on injection processes and mixture preparation is pointed out. The joint effect of both cycle-to-cycle velocity fluctuations and variable spray boundary conditions is discussed in terms of mean and standard deviation of relative air-fuel ratio, velocity and mass fraction. Finally a qualitative analysis of the intensity of cyclic fluctuations below the spark plug is provided.

Clinical characteristics, etiology and antimicrobial susceptibility among overweight and obese individuals with diarrhea: observed at a large diarrheal disease hospital, Bangladesh.

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Sumon Kumar Das

Full Text Available BACKGROUND: The present study aimed to determine the clinical characteristics and etiology of overweight and obese (OO individuals with diarrhea attending an urban Dhaka Hospital, International Centre for Diarrheal Disease Research (icddr,b, Bangladesh. METHODS: Total of 508 under-5 children, 96 individuals of 5-19 years and 1331 of >19 years were identified as OO from the Diarrheal Disease Surveillance System (DDSS between 1993-2011. Two comparison groups such as well-nourished and malnourished individuals from respective age stratums were selected. RESULTS: Isolation rate of rotavirus was higher among OO under-5 children compared to malnourished group (46% vs. 28%. Rotavirus infection among OO individuals aged 5-19 years (9% vs. 3% (9% vs. 3% and >19 years (6% vs. 4% (6% vs. 3% was higher compared to well-nourished and malnourished children. Conversely, Vibrio cholerae was lower among all OO age groups compared to well-nourished and malnourished ones. Shigella (4% vs. 6% (4% vs. 8%, and Campylobacter (3% vs. 5% (3% vs. 5% were lower only among OO in >19 years individuals compared to their counterparts of the same age stratum. Salmonella was similarly isolated in all age strata and nutritional groups. In multinomial logistic regression among under-5 children, significant association was observed only with use of antimicrobials at home [OR-1.97] and duration of hospital stay [OR-0.68]. For individuals aged 5-19 years, use of antimicrobials at home (OR-1.83, some or severe dehydration (OR-3.12, having received intravenous saline (OR-0.46 and rotavirus diarrhea (OR-2.96 were found to be associated with OO respectively. Moreover, significant associations were also found for duration of diarrhea before coming to hospital (>24 hours (OR-1.24, Shigella (OR-0.46, and Campylobacter (OR-0.58 among >19 years OO individuals along with other associated co-variates in 5-19 years group (all p<0.05. CONCLUSION AND SIGNIFICANCE: Higher proportion of OO were

Individual behavioural characteristics in pigs and their consequences for pig husbandry

NARCIS (Netherlands)

Hessing, M.J.C.

1994-01-01

Introduction
The main aspect of this thesis is individual behavioural variation. Behavioural variability among individuals within a population may provide information on strategies or roles in social behaviour, on personality traits and individual recognition.

Effect of litter size on the variation in birth and weaning weights of Landrace piglets

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Camila Duarte Prazeres

2016-03-01

Full Text Available The objective of this study was to evaluate the effect of the size class of the litter at birth on the variation in birth and weaning weights and on the survival rate of piglets from birth to weaning. For this purpose, records of individual weight at birth and weaning of piglets obtained from a database of 295 Landrace litters born between 2000 and 2010 on a pig farm in the western region of the State of Paraná were used. The litters were classified as small (up to 7 piglets, medium (8 to 13 piglets, and large (> 14 piglets according to the total number of piglets born. The data were analyzed considering the effects of the year of sow mating and size class of the litter at birth. The correlations between mean weight and variance in litter weight and size were higher for medium and large litters. The size class of the litter significantly influenced the mean weight of piglets at birth and weaning and the variance in birth weight. Piglets born in medium and large litters weighed less and exhibited greater birth weight variation and a lower survival rate until weaning than piglets born in small litters.

Regional Inequalities in Lung Cancer Mortality in Belgium at the Beginning of the 21st Century: The Contribution of Individual and Area-Level Socioeconomic Status and Industrial Exposure.

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Paulien Hagedoorn

Full Text Available Being a highly industrialized country with one of the highest male lung cancer mortality rates in Europe, Belgium is an interesting study area for lung cancer research. This study investigates geographical patterns in lung cancer mortality in Belgium. More specifically it probes into the contribution of individual as well as area-level characteristics to (sub-district patterns in lung cancer mortality. Data from the 2001 census linked to register data from 2001-2011 are used, selecting all Belgian inhabitants aged 65+ at time of the census. Individual characteristics include education, housing status and home ownership. Urbanicity, unemployment rate, the percentage employed in mining and the percentage employed in other high-risk industries are included as sub-district characteristics. Regional variation in lung cancer mortality at sub-district level is estimated using directly age-standardized mortality rates. The association between lung cancer mortality and individual and area characteristics, and their impact on the variation of sub-district level is estimated using multilevel Poisson models. Significant sub-district variations in lung cancer mortality are observed. Individual characteristics explain a small share of this variation, while a large share is explained by sub-district characteristics. Individuals with a low socioeconomic status experience a higher lung cancer mortality risk. Among women, an association with lung cancer mortality is found for the sub-district characteristics urbanicity and unemployment rate, while for men lung cancer mortality was associated with the percentage employed in mining. Not just individual characteristics, but also area characteristics are thus important determinants of (regional differences in lung cancer mortality.

Variation among chlorine concentration ratios for native and agronomic plants

International Nuclear Information System (INIS)

Sheppard, S.C.; Evenden, W.G.; Macdonald, C.R.

1999-01-01

Variation among plant/soil concentration ratios (CRs) for important radionuclides requires attention because it is a major source of uncertainty in nuclear environmental safety assessments. For agronomic plants, variation among plant species is easy to deal with because there are relatively few species. In natural settings, there are vastly more species and the question becomes how to develop representative statistical distributions of CRs. Chlorine (Cl) is a good element with which to address this problem, because 36 Cl is a key radionuclide in nuclear waste disposal and yet stable Cl is easily measured in the environment. We measured CRs (dry weight basis) for Cl among edible parts of agronomic plants at one site, and found a geometric mean (GM) of 10, a geometric standard deviation (GSD) of 1.9 and a range of 5-66. When the GM was weighted by the relative contributions of the various plants to the human diet, it rose to 16. Among native plants at five sites, each site representative of a specific environment, the GMs were 4.0-13 and the GSDs were 2.9-6.2. The CRs for individual species ranged from 0.8 to 170. However, when weighted by relative contributions of the plants to selected animal diets, the GMs were as high as 50. The conclusions are that: the variation in CR for agronomic plants is a subset of the variation among native or all plants, variation among species (the GSD) can be sixfold, and variation among species is large enough that typical diets of specific animals could expose them to several-fold higher amounts of Cl (or 36 Cl) than expected from generic CR values. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

MPQS with three large primes

NARCIS (Netherlands)

Leyland, P.; Lenstra, A.K.; Dodson, B.; Muffett, A.; Wagstaff, S.; Fieker, C.; Kohel, D.R.

2002-01-01

We report the factorization of a 135-digit integer by the triple-large-prime variation of the multiple polynomial quadratic sieve. Previous workers [6][10] had suggested that using more than two large primes would be counterproductive, because of the greatly increased number of false reports from

Convergence analysis of variational and non-variational multigrid algorithms for the Laplace-Beltrami operator

KAUST Repository

Bonito, Andrea

2012-09-01

We design and analyze variational and non-variational multigrid algorithms for the Laplace-Beltrami operator on a smooth and closed surface. In both cases, a uniform convergence for the V -cycle algorithm is obtained provided the surface geometry is captured well enough by the coarsest grid. The main argument hinges on a perturbation analysis from an auxiliary variational algorithm defined directly on the smooth surface. In addition, the vanishing mean value constraint is imposed on each level, thereby avoiding singular quadratic forms without adding additional computational cost. Numerical results supporting our analysis are reported. In particular, the algorithms perform well even when applied to surfaces with a large aspect ratio. © 2011 American Mathematical Society.