The Key Factors Affecting Students' Individual Interest in School Science Lessons

ERIC Educational Resources Information Center

Cheung, Derek

2018-01-01

Individual interest in school science lessons can be defined as a relatively stable and enduring personal emotion comprising affective and behavioural reactions to events in the regular science lessons at school. Little research has compared the importance of different factors affecting students' individual interest in school science lessons. The…

Moralized Rationality: Relying on Logic and Evidence in the Formation and Evaluation of Belief Can Be Seen as a Moral Issue.

PubMed

Ståhl, Tomas; Zaal, Maarten P; Skitka, Linda J

2016-01-01

In the present article we demonstrate stable individual differences in the extent to which a reliance on logic and evidence in the formation and evaluation of beliefs is perceived as a moral virtue, and a reliance on less rational processes is perceived as a vice. We refer to this individual difference variable as moralized rationality. Eight studies are reported in which an instrument to measure individual differences in moralized rationality is validated. Results show that the Moralized Rationality Scale (MRS) is internally consistent, and captures something distinct from the personal importance people attach to being rational (Studies 1-3). Furthermore, the MRS has high test-retest reliability (Study 4), is conceptually distinct from frequently used measures of individual differences in moral values, and it is negatively related to common beliefs that are not supported by scientific evidence (Study 5). We further demonstrate that the MRS predicts morally laden reactions, such as a desire for punishment, of people who rely on irrational (vs. rational) ways of forming and evaluating beliefs (Studies 6 and 7). Finally, we show that the MRS uniquely predicts motivation to contribute to a charity that works to prevent the spread of irrational beliefs (Study 8). We conclude that (1) there are stable individual differences in the extent to which people moralize a reliance on rationality in the formation and evaluation of beliefs, (2) that these individual differences do not reduce to the personal importance attached to rationality, and (3) that individual differences in moralized rationality have important motivational and interpersonal consequences.

Moralized Rationality: Relying on Logic and Evidence in the Formation and Evaluation of Belief Can Be Seen as a Moral Issue

PubMed Central

Skitka, Linda J.

2016-01-01

In the present article we demonstrate stable individual differences in the extent to which a reliance on logic and evidence in the formation and evaluation of beliefs is perceived as a moral virtue, and a reliance on less rational processes is perceived as a vice. We refer to this individual difference variable as moralized rationality. Eight studies are reported in which an instrument to measure individual differences in moralized rationality is validated. Results show that the Moralized Rationality Scale (MRS) is internally consistent, and captures something distinct from the personal importance people attach to being rational (Studies 1–3). Furthermore, the MRS has high test-retest reliability (Study 4), is conceptually distinct from frequently used measures of individual differences in moral values, and it is negatively related to common beliefs that are not supported by scientific evidence (Study 5). We further demonstrate that the MRS predicts morally laden reactions, such as a desire for punishment, of people who rely on irrational (vs. rational) ways of forming and evaluating beliefs (Studies 6 and 7). Finally, we show that the MRS uniquely predicts motivation to contribute to a charity that works to prevent the spread of irrational beliefs (Study 8). We conclude that (1) there are stable individual differences in the extent to which people moralize a reliance on rationality in the formation and evaluation of beliefs, (2) that these individual differences do not reduce to the personal importance attached to rationality, and (3) that individual differences in moralized rationality have important motivational and interpersonal consequences. PMID:27851777

Diet-to-female and female-to-pup isotopic discrimination in South American sea lions.

PubMed

Drago, Massimiliano; Franco-Trecu, Valentina; Cardona, Luis; Inchausti, Pablo

2015-08-30

The use of accurate, species-specific diet-tissue discrimination factors is a critical requirement when applying stable isotope mixing models to predict consumer diet composition. Thus, diet-to-female and female-to-pup isotopic discrimination factors in several tissues for both captive and wild South American sea lions were estimated to provide appropriate values for quantifying feeding preferences at different timescales in the wild populations of this species. Stable carbon and nitrogen isotope ratios in the blood components of two female-pup pairs and females' prey muscle from captive individuals were determined by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS) to calculate the respective isotopic discrimination factors. The same analysis was carried out in both blood components, and skin and hair tissues for eight female-pup pairs from wild individuals. Mean diet-to-female Δ(13) C and Δ(15) N values were higher than the female-to-pup ones. Pup tissues were more (15) N-enriched than their mothers but (13) C-depleted in serum and plasma tissues. In most of the tissue comparisons, we found differences in both Δ(15) N and Δ(13) C values, supporting tissue-specific discrimination. We found no differences between captive and wild female-to-pup discrimination factors either in Δ(13) C or Δ(15) N values of blood components. Only the stable isotope ratios in pup blood are good proxies of the individual lactating females. Thus, we suggest that blood components are more appropriate to quantify the feeding habits of wild individuals of this species. Furthermore, because female-to-pup discrimination factors for blood components did not differ between captive and wild individuals, we suggest that results for captive experiments can be extrapolated to wild South American sea lion populations. Copyright © 2015 John Wiley & Sons, Ltd.

Understanding Individual Differences in Language Development across the School Years. Language and Speech Disorders

ERIC Educational Resources Information Center

Tomblin, J. Bruce, Ed.; Nippold, Marilyn A., Ed.

2014-01-01

This volume presents the findings of a large-scale study of individual differences in spoken (and heard) language development during the school years. The goal of the study was to investigate the degree to which language abilities at school entry were stable over time and influential in the child's overall success in important aspects of…

Cognitive models of risky choice: parameter stability and predictive accuracy of prospect theory.

PubMed

Glöckner, Andreas; Pachur, Thorsten

2012-04-01

In the behavioral sciences, a popular approach to describe and predict behavior is cognitive modeling with adjustable parameters (i.e., which can be fitted to data). Modeling with adjustable parameters allows, among other things, measuring differences between people. At the same time, parameter estimation also bears the risk of overfitting. Are individual differences as measured by model parameters stable enough to improve the ability to predict behavior as compared to modeling without adjustable parameters? We examined this issue in cumulative prospect theory (CPT), arguably the most widely used framework to model decisions under risk. Specifically, we examined (a) the temporal stability of CPT's parameters; and (b) how well different implementations of CPT, varying in the number of adjustable parameters, predict individual choice relative to models with no adjustable parameters (such as CPT with fixed parameters, expected value theory, and various heuristics). We presented participants with risky choice problems and fitted CPT to each individual's choices in two separate sessions (which were 1 week apart). All parameters were correlated across time, in particular when using a simple implementation of CPT. CPT allowing for individual variability in parameter values predicted individual choice better than CPT with fixed parameters, expected value theory, and the heuristics. CPT's parameters thus seem to pick up stable individual differences that need to be considered when predicting risky choice. Copyright © 2011 Elsevier B.V. All rights reserved.

Predicting risk in space: Genetic markers for differential vulnerability to sleep restriction

NASA Astrophysics Data System (ADS)

Goel, Namni; Dinges, David F.

2012-08-01

Several laboratories have found large, highly reliable individual differences in the magnitude of cognitive performance, fatigue and sleepiness, and sleep homeostatic vulnerability to acute total sleep deprivation and to chronic sleep restriction in healthy adults. Such individual differences in neurobehavioral performance are also observed in space flight as a result of sleep loss. The reasons for these stable phenotypic differential vulnerabilities are unknown: such differences are not yet accounted for by demographic factors, IQ or sleep need, and moreover, psychometric scales do not predict those individuals cognitively vulnerable to sleep loss. The stable, trait-like (phenotypic) inter-individual differences observed in response to sleep loss—with intraclass correlation coefficients accounting for 58-92% of the variance in neurobehavioral measures—point to an underlying genetic component. To this end, we utilized multi-day highly controlled laboratory studies to investigate the role of various common candidate gene variants—each independently—in relation to cumulative neurobehavioral and sleep homeostatic responses to sleep restriction. These data suggest that common genetic variations (polymorphisms) involved in sleep-wake, circadian, and cognitive regulation may serve as markers for prediction of inter-individual differences in sleep homeostatic and neurobehavioral vulnerability to sleep restriction in healthy adults. Identification of genetic predictors of differential vulnerability to sleep restriction—as determined from candidate gene studies—will help identify astronauts most in need of fatigue countermeasures in space flight and inform medical standards for obtaining adequate sleep in space. This review summarizes individual differences in neurobehavioral vulnerability to sleep deprivation and ongoing genetic efforts to identify markers of such differences.

Relationship of Serum Klotho Level With ACE Gene Polymorphism in Stable Kidney Allograft Recipients.

PubMed

Zaare Nahandi, Maryam; Ardalan, Mohamad Reza; Banagozar Mohamadi, Ali; Ghorbani Haghjo, Amir; Jabbarpor Bonyadi, Morteza; Mohamadian, Tahere

2017-03-01

The kidney is the main source of serum Klotho production. Immunosuppressive agents could affect the kidney in this regard. The effect of the ACE gene polymorphism on Klotho production is a less studied area. This study aimed to assess serum Klotho and ACE gene in a group of stable kidney transplant recipients. In a cross-sectional study, 30 kidney transplant recipients with stable allograft function and 27 healthy young individuals were assessed for their serum Klotho levels. The ACE gene polymorphisms were studied in both groups. Klotho level was higher in kidney transplant recipients than the controls, but the difference was not significant (2.76 ± 2.41 ng/mL versus 2.01 ± 1.41 ng/mL, respectively). In both groups, serum Klotho level was higher in those with the I>I polymorphism, the men, those with higher glomerular filtration rate, and younger individuals, but the differences did not reach a significant level. Higher body mass index was significantly associated with lower serum Klotho level in both groups. Klotho level after kidney transplantation meets the range in healthy individuals, and it is not affected by the ACE gene polymorphism.

Stability and change of personality traits, self-esteem, and well-being: Introducing the meta-analytic stability and change model of retest correlations.

PubMed

Anusic, Ivana; Schimmack, Ulrich

2016-05-01

The stability of individual differences is a fundamental issue in personality psychology. Although accumulating evidence suggests that many psychological attributes are both stable and change over time, existing research rarely takes advantage of theoretical models that capture both stability and change. In this article, we present the Meta-Analytic Stability and Change model (MASC), a novel meta-analytic model for synthesizing data from longitudinal studies. MASC is based on trait-state models that can separate influences of stable and changing factors from unreliable variance (Kenny & Zautra, 1995). We used MASC to evaluate the extent to which personality traits, life satisfaction, affect, and self-esteem are influenced by these different factors. The results showed that the majority of reliable variance in personality traits is attributable to stable influences (83%). Changing factors had a greater influence on reliable variance in life satisfaction, self-esteem, and affect than in personality (42%-56% vs. 17%). In addition, changing influences on well-being were more stable than changing influences on personality traits, suggesting that different changing factors contribute to personality and well-being. Measures of affect were less reliable than measures of the other 3 constructs, reflecting influences of transient factors, such as mood on affective judgments. After accounting for differences in reliability, stability of affect did not differ from other well-being variables. Consistent with previous research, we found that stability of individual differences increases with age. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Personality stability is associated with better cognitive performance in adulthood: are the stable more able?

PubMed

Graham, Eileen K; Lachman, Margie E

2012-09-01

Although personality is relatively stable over time, there are individual differences in the patterns and magnitude of change. There is some evidence that personality change in adulthood is related to physical health and longevity. The present study expanded this work to consider whether personality stability or change would be associated with better cognitive functioning, especially in later adulthood. A total of 4,974 individuals participated in two waves of The Midlife in the United States Study (MIDUS) in 1994-1995 and 2004-2005. Participants completed the MIDUS personality inventory at both times and the Brief Test of Adult Cognition by Telephone cognitive battery at Time 2. Multiple regression and analysis of covariance analyses showed that, consistent with predictions, individuals remaining stable in openness to experience and neuroticism had faster reaction times and better inductive reasoning than those who changed. Among older adults, those who remained stable or decreased in neuroticism had significantly faster reaction times than those who increased. As predicted, personality stability on some traits was associated with more adaptive cognitive performance on reasoning and reaction time. Personality is discussed as a possible resource for protecting against or minimizing age-related declines in cognition.

Domain independence and stability in young and older adults' discounting of delayed rewards

PubMed Central

Jimura, Koji; Myerson, Joel; Hilgard, Joseph; Keighley, Julia; Braver, Todd S.; Green, Leonard

2011-01-01

Individual discounting rates for different types of delayed reward are typically assumed to reflect a single, underlying trait of impulsivity. Recently, we showed that discounting rates are orders of magnitude steeper for directly consumable liquid rewards than for monetary rewards (Jimura et al. 2009), raising the question of whether discounting rates for different types of reward covary at the individual level. Accordingly, the present study examined the relation between discounting of hypothetical money and real liquid rewards in young adults (Experiment 1) and older adults (Experiment 2). At the group level, young adults discounted monetary rewards more steeply than the older adults, but the reverse pattern was observed with liquid rewards. At the individual level, the rates at which young and older participants discounted each reward type were stable over a two- to fifteen-week interval (rs >.70), but there was no significant correlation between the rates at which they discounted the two reward types. These results suggest that although similar decision-making processes may underlie the discounting of different types of rewards, the rates at which individuals discount money and directly consumable rewards may reflect separate, stable traits, rather than a single trait of impulsivity. PMID:21550384

Why Some People Discount More than Others: Baseline Activation in the Dorsal PFC Mediates the Link between COMT Genotype and Impatient Choice

PubMed Central

Gianotti, Lorena R. R.; Figner, Bernd; Ebstein, Richard P.; Knoch, Daria

2012-01-01

Individuals differ widely in how steeply they discount future rewards. The sources of these stable individual differences in delay discounting (DD) are largely unknown. One candidate is the COMT Val158Met polymorphism, known to modulate prefrontal dopamine levels and affect DD. To identify possible neural mechanisms by which this polymorphism may contribute to stable individual DD differences, we measured 73 participants’ neural baseline activation using resting electroencephalogram (EEG). Such neural baseline activation measures are highly heritable and stable over time, thus an ideal endophenotype candidate to explain how genes may influence behavior via individual differences in neural function. After EEG-recording, participants made a series of incentive-compatible intertemporal choices to determine the steepness of their DD. We found that COMT significantly affected DD and that this effect was mediated by baseline activation level in the left dorsal prefrontal cortex (DPFC): (i) COMT had a significant effect on DD such that the number of Val alleles was positively correlated with steeper DD (higher numbers of Val alleles means greater COMT activity and thus lower dopamine levels). (ii) A whole-brain search identified a cluster in left DPFC where baseline activation was correlated with DD; lower activation was associated with steeper DD. (iii) COMT had a significant effect on the baseline activation level in this left DPFC cluster such that a higher number of Val alleles was associated with lower baseline activation. (iv) The effect of COMT on DD was explained by the mediating effect of neural baseline activation in the left DPFC cluster. Our study thus establishes baseline activation level in left DPFC as salient neural signature in the form of an endophenotype that mediates the link between COMT and DD. PMID:22586360

Stable isotope analyses-A method to distinguish intensively farmed from wild frogs.

PubMed

Dittrich, Carolin; Struck, Ulrich; Rödel, Mark-Oliver

2017-04-01

Consumption of frog legs is increasing worldwide, with potentially dramatic effects for ecosystems. More and more functioning frog farms are reported to exist. However, due to the lack of reliable methods to distinguish farmed from wild-caught individuals, the origin of frogs in the international trade is often uncertain. Here, we present a new methodological approach to this problem. We investigated the isotopic composition of legally traded frog legs from suppliers in Vietnam and Indonesia. Muscle and bone tissue samples were examined for δ 15 N, δ 13 C, and δ 18 O stable isotope compositions, to elucidate the conditions under which the frogs grew up. We used DNA barcoding (16S rRNA) to verify species identities. We identified three traded species ( Hoplobatrachus rugulosus, Fejervarya cancrivora and Limnonectes macrodon ); species identities were partly deviating from package labeling. Isotopic values of δ 15 N and δ 18 O showed significant differences between species and country of origin. Based on low δ 15 N composition and generally little variation in stable isotope values, our results imply that frogs from Vietnam were indeed farmed. In contrast, the frogs from the Indonesian supplier likely grew up under natural conditions, indicated by higher δ 15 N values and stronger variability in the stable isotope composition. Our results indicate that stable isotope analyses seem to be a useful tool to distinguish between naturally growing and intensively farmed frogs. We believe that this method can be used to improve the control in the international trade of frog legs, as well as for other biological products, thus supporting farming activities and decreasing pressure on wild populations. However, we examined different species from different countries and had no access to samples of individuals with confirmed origin and living conditions. Therefore, we suggest improving this method further with individuals of known origin and history, preferably including samples of the respective nutritive bases.

Individual Differences in False Belief Understanding Are Stable from 3 to 6 Years of Age and Predict Children's Mental State Talk with School Friends

ERIC Educational Resources Information Center

Hughes, Claire; Ensor, Rosie; Marks, Alex

2011-01-01

Despite a wealth of studies in the field, longitudinal assessments of both the stability and predictive utility of individual differences in preschoolers' understanding of the mind remain scarce. To address these gaps, we applied latent variable analyses to (a) experimental data gathered from a socially diverse sample (N = 101, 60 boys and 41…

Domain independence and stability in young and older adults' discounting of delayed rewards.

PubMed

Jimura, Koji; Myerson, Joel; Hilgard, Joseph; Keighley, Julia; Braver, Todd S; Green, Leonard

2011-07-01

Individual discounting rates for different types of delayed reward are typically assumed to reflect a single, underlying trait of impulsivity. Recently, we showed that discounting rates are orders of magnitude steeper for directly consumable liquid rewards than for monetary rewards (Jimura et al., 2009), raising the question of whether discounting rates for different types of reward covary at the individual level. Accordingly, the present study examined the relation between discounting of hypothetical money and real liquid rewards in young adults (Experiment 1) and older adults (Experiment 2). At the group level, young adults discounted monetary rewards more steeply than the older adults, but there was no significant age difference with respect to liquid rewards. At the individual level, the rates at which young and older participants discounted each reward type were stable over a two- to fifteen-week interval (rs>70), but there was no significant correlation between the rates at which they discounted the two reward types. These results suggest that although similar decision-making processes may underlie the discounting of different types of rewards, the rates at which individuals discount money and directly consumable rewards may reflect separate, stable traits, rather than a single trait of impulsivity. Copyright © 2011 Elsevier B.V. All rights reserved.

Individual differences and their measurement: A review of 100 years of research.

PubMed

Sackett, Paul R; Lievens, Filip; Van Iddekinge, Chad H; Kuncel, Nathan R

2017-03-01

This article reviews 100 years of research on individual differences and their measurement, with a focus on research published in the Journal of Applied Psychology. We focus on 3 major individual differences domains: (a) knowledge, skill, and ability, including both the cognitive and physical domains; (b) personality, including integrity, emotional intelligence, stable motivational attributes (e.g., achievement motivation, core self-evaluations), and creativity; and (c) vocational interests. For each domain, we describe the evolution of the domain across the years and highlight major theoretical, empirical, and methodological developments, including relationships between individual differences and variables such as job performance, job satisfaction, and career development. We conclude by discussing future directions for individual differences research. Trends in the literature include a growing focus on substantive issues rather than on the measurement of individual differences, a differentiation between constructs and measurement methods, and the use of innovative ways of assessing individual differences, such as simulations, other-reports, and implicit measures. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Are Some Negotiators Better Than Others? Individual Differences in Bargaining Outcomes

PubMed Central

Elfenbein, Hillary Anger; Curhan, Jared R.; Eisenkraft, Noah; Shirako, Aiwa; Baccaro, Lucio

2008-01-01

The authors address the long-standing mystery of stable individual differences in negotiation performance, on which intuition and conventional wisdom have clashed with inconsistent empirical findings. The present study used the Social Relations Model to examine individual differences directly via consistency in performance across multiple negotiations and to disentangle the roles of both parties within these inherently dyadic interactions. Individual differences explained a substantial 46% of objective performance and 19% of subjective performance in a mixed-motive bargaining exercise. Previous work may have understated the influence of individual differences because conventional research designs require specific traits to be identified and measured. Exploratory analyses of a battery of traits revealed few reliable associations with consistent individual differences in objective performance—except for positive beliefs about negotiation, positive affect, and concern for one's outcome, each of which predicted better performance. Findings suggest that the field has large untapped potential to explain substantial individual differences. Limitations, areas for future research, and practical implications are discussed. PMID:21720453

Verbal learning changes in older adults across 18 months.

PubMed

Zimprich, Daniel; Rast, Philippe

2009-07-01

The major aim of this study was to investigate individual changes in verbal learning across a period of 18 months. Individual differences in verbal learning have largely been neglected in the last years and, even more so, individual differences in change in verbal learning. The sample for this study comes from the Zurich Longitudinal Study on Cognitive Aging (ZULU; Zimprich et al., 2008a) and comprised 336 older adults in the age range of 65-80 years at first measurement occasion. In order to address change in verbal learning we used a latent change model of structured latent growth curves to account for the non-linearity of the verbal learning data. The individual learning trajectories were captured by a hyperbolic function which yielded three psychologically distinct parameters: initial performance, learning rate, and asymptotic performance. We found that average performance increased with respect to initial performance, but not in learning rate or in asymptotic performance. Further, variances and covariances remained stable across both measurement occasions, indicating that the amount of individual differences in the three parameters remained stable, as did the relationships among them. Moreover, older adults differed reliably in their amount of change in initial performance and asymptotic performance. Eventually, changes in asymptotic performance and learning rate were strongly negatively correlated. It thus appears as if change in verbal learning in old age is a constrained process: an increase in total learning capacity implies that it takes longer to learn. Together, these results point to the significance of individual differences in change of verbal learning in the elderly.

The effect of social environment on markers of vascular oxidative stress and inflammation in the Watanabe heritable hyperlipidemic rabbit.

PubMed

Nation, Daniel A; Gonzales, Julie A; Mendez, Armando J; Zaias, Julia; Szeto, Angela; Brooks, Larry G; Paredes, Jamespaul; D'Angola, Alyssa; Schneiderman, Neil; McCabe, Philip M

2008-04-01

Previous research demonstrated that social environment can influence progression of atherosclerosis in the Watanabe Heritable Hyperlipidemic (WHHL) rabbit. This study examined the effect of social environment on markers of oxidative stress and inflammation to clarify the physiological pathways potentially responsible for the influence of social environment on disease. WHHL rabbits were assigned to 1 of 3 social groups: an unstable group, in which unfamiliar rabbits were paired daily, with the pairing switched each week; a stable group, in which littermates were paired daily; and an individually-caged group. The stable group engaged in more affiliative social behavior than the unstable group. The unstable group showed more agonistic behavior compared with the stable group and higher C-reactive protein levels than the individually caged group. The individually caged group was behaviorally sedentary, had higher 24-hour urinary catecholamine levels than the other groups, and exhibited higher NAD(P)H-oxidase activity in the aortic arch relative to the stable group. The results suggest that social environment creates distinct behavioral contexts that can affect markers of inflammation and oxidative stress early in the development of atherosclerosis. Specifically, physical inactivity associated with individual caging affects indices of oxidative stress and inflammation. These pathophysiological markers may help to explain behaviorally related differences in the extent of atherosclerosis observed in prior studies.

Stable isotope evidence for sex- and status-based variations in diet and life history at medieval Trino Vercellese, Italy.

PubMed

Reitsema, Laurie J; Vercellotti, Giuseppe

2012-08-01

The medieval period in Europe was a time of unprecedented social complexity that affected human diet. The diets of certain subgroups-for example, children, women, and the poor-are chronically underrepresented in historical sources from the medieval period. To better understand diet and the distribution of foods during the medieval period, we investigated stable carbon and nitrogen isotope ratios of 30 individuals from Trino Vercellese, Northern Italy (8th-13th c.). Specifically, we examined diet differences between subgroups (males and females, and high- and low-status individuals), and diet change throughout the life course among these groups by comparing dentine and bone collagen. Our results show a diet based on terrestrial resources with input from C(4) plants, which could include proso and/or foxtail millet. Diets of low-status males differ from those of females (both status groups) and of high-status males. These differences develop in adulthood. Childhood diets are similar among the subgroups, but sex- and status-based differences appear in adulthood. We discuss the possibility of cultural buffering and dietary selectivity of females and high-status individuals. Copyright © 2012 Wiley Periodicals, Inc.

Biochemical properties of beta-glucosidase in leukocytes from patients and obligated heterozygotes for Gaucher disease carriers.

PubMed

Michelin, Kristiane; Wajner, Alessandro; Bock, Hugo; Fachel, Angela; Rosenberg, Roberto; Pires, Ricardo Flores; Pereira, Maria Luiza Saraiva; Giugliani, Roberto; Coelho, Janice Carneiro

2005-12-01

Gaucher's disease (GD) is a disorder caused by the deficiency of lysosomal beta-glucosidase, an enzyme that participates in the degradation of glycosphingolipids. Deficiency of this enzyme results in the storage of glucocerebrosides in lysosomes of macrophage. No studies are available in the literature comparing biochemical and kinetic behavior of this enzyme in leukocytes and fibroblasts from normal individuals, obligate heterozygotes and patients with GD. The behavior of beta-glu in terms of optimum pH, heat stability, Km and Vmax in leukocytes from patients with GD and obligated heterozygotes with different genotypes and normal individuals were characterized. Optimum pH was similar in all groups analyzed. In terms of Km and Vmax, several differences among heterozygotes and homozygotes groups and among these groups and normal enzyme were observed. Enzyme from all groups were inactivated when preincubated at 60 degrees C, but some enzymes were more stable than other. Results showed a different behavior of the enzyme in the 3 groups under analysis. Such behavior varied according to individual mutation. The catalytic gradient presented by beta-glu allowed the correlation of N370S mutation-which presented more stable biochemical properties-with the non-neurological clinical condition of the disease and the catalytically less stable mutation (D409H), with the neurological clinical condition of GD. This study contributes to a better understanding of the repercussion of the different mutations on the protein function, thus allowing to predict the severity of such complex metabolic disorder and to anticipate the most appropriate intervention for each case specifically.

In Defence of Situational Morality: Genetic, Dispositional and Situational Determinants of Children's Donating to Charity

ERIC Educational Resources Information Center

van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Pannebakker, Fieke; Out, Dorothee

2010-01-01

In this paper we argue that moral behaviour is largely situation-specific. Genetic make-up, neurobiological factors, attachment security and rearing experiences have only limited influence on individual differences in moral performance. Moral behaviour does not develop in a linear and cumulative fashion and individual morality is not stable across…

Asian American Self-Concept.

ERIC Educational Resources Information Center

Ito, Karen L.; Tashima, Eugene

While an individual in his own culture is expected to have a stable self concept, one who is placed in a totally different context may experience difficulties because ideas about self in the old society are no longer appropriate in the new one. In order to survive, the individual has to redefine his self concept to make it more functional in the…

Identifying Two Groups of Entitled Individuals: Cluster Analysis Reveals Emotional Stability and Self-Esteem Distinction.

PubMed

Crowe, Michael L; LoPilato, Alexander C; Campbell, W Keith; Miller, Joshua D

2016-12-01

The present study hypothesized that there exist two distinct groups of entitled individuals: grandiose-entitled, and vulnerable-entitled. Self-report scores of entitlement were collected for 916 individuals using an online platform. Model-based cluster analyses were conducted on the individuals with scores one standard deviation above mean (n = 159) using the five-factor model dimensions as clustering variables. The results support the existence of two groups of entitled individuals categorized as emotionally stable and emotionally vulnerable. The emotionally stable cluster reported emotional stability, high self-esteem, more positive affect, and antisocial behavior. The emotionally vulnerable cluster reported low self-esteem and high levels of neuroticism, disinhibition, conventionality, psychopathy, negative affect, childhood abuse, intrusive parenting, and attachment difficulties. Compared to the control group, both clusters reported being more antagonistic, extraverted, Machiavellian, and narcissistic. These results suggest important differences are missed when simply examining the linear relationships between entitlement and various aspects of its nomological network.

Positive and negative affect dimensions in chronic knee osteoarthritis: effects on clinical and laboratory pain.

PubMed

Finan, Patrick H; Quartana, Phillip J; Smith, Michael T

2013-06-01

This study investigated whether daily and laboratory assessed pain differs as a function of the temporal stability and valence of affect in individuals with chronic knee osteoarthritis (KOA). One hundred fifty-one men and women with KOA completed 14 days of electronic diaries assessing positive affect (PA), negative affect (NA), and clinical pain. A subset of participants (n =79) engaged in quantitative sensory testing (QST). State PA and NA were assessed prior to administration of stimuli that induced suprathreshold pain and temporal summation. Multilevel modeling and multiple regression evaluated associations of affect and pain as a function of valence (i.e., positive versus negative) and stability (i.e., stable versus state). In the diary, stable NA (B = -.63, standard error [SE] = .13, p < .001) was a stronger predictor of clinical KOA pain than stable PA (B = -.18, SE = .11, p = .091), and state PA (B = -.09, p < .001) was a stronger predictor of concurrent daily clinical pain than state NA (B = .04, SE = .02, p = .068). In the laboratory, state PA (B = -.05, SE = .02, p = .042), but not state NA (p = .46), predicted diminished temporal summation of mechanical pain. Stable NA is more predictive of clinical pain than stable PA, whereas state PA is more predictive of both clinical and laboratory pain than state NA. The findings suggest that dynamic affect-pain processes in the field may reflect individual differences in central pain facilitation.

You are what you eat: diet shapes body composition, personality and behavioural stability.

PubMed

Han, Chang S; Dingemanse, Niels J

2017-01-10

Behavioural phenotypes vary within and among individuals. While early-life experiences have repeatedly been proposed to underpin interactions between these two hierarchical levels, the environmental factors causing such effects remain under-studied. We tested whether an individual's diet affected both its body composition, average behaviour (thereby causing among-individual variation or 'personality') and within-individual variability in behaviour and body weight (thereby causing among-individual differences in residual within-individual variance or 'stability'), using the Southern field cricket Gryllus bimaculatus as a model. We further asked whether effects of diet on the expression of these variance components were sex-specific. Manipulating both juvenile and adult diet in a full factorial design, individuals were put, in each life-stage, on a diet that was either relatively high in carbohydrates or relatively high in protein. We subsequently measured the expression of multiple behavioural (exploration, aggression and mating activity) and morphological traits (body weight and lipid mass) during adulthood. Dietary history affected both average phenotype and level of within-individual variability: males raised as juveniles on high-protein diets were heavier, more aggressive, more active during mating, and behaviourally less stable, than conspecifics raised on high-carbohydrate diets. Females preferred more protein in their diet compared to males, and dietary history affected average phenotype and within-individual variability in a sex-specific manner: individuals raised on high-protein diets were behaviourally less stable in their aggressiveness but this effect was only present in males. Diet also influenced individual differences in male body weight, but within-individual variance in female body weight. This study thereby provides experimental evidence that dietary history explains both heterogeneous residual within-individual variance (i.e., individual variation in 'behavioural stability') and individual differences in average behaviour (i.e., 'personality'), though dietary effects were notably trait-specific. These findings call for future studies integrating proximate and ultimate perspectives on the role of diet in the evolution of repeatedly expressed traits, such as behaviour and body weight.

Trait and Social Influences in the Links among Adolescent Attachment, Depressive Symptoms, and Coping

ERIC Educational Resources Information Center

Merlo, Lisa J.; Lakey, Brian

2007-01-01

Attachment insecurity and maladaptive coping are associated with depression in adolescence; however, it is unclear whether these links primarily reflect stable individual differences among teens (trait influences), experiential differences in their interactions with relationship partners (social influences) or both. In this study, teens (ages…

Evidence of cryptic individual specialization in an opportunistic insectivorous bat

USGS Publications Warehouse

Cryan, Paul M.; Stricker, Craig A.; Wunder, Michael B.

2012-01-01

Habitat use and feeding behaviors of cryptic animals are often poorly understood. Analyses of stable isotope ratios in animal body tissues can help reveal an individual's location and resource use during tissue growth. We investigated variation in stable isotope ratios of 4 elements (H, C, N, and S) in the hair of a sedentary species of insectivorous bat (Eptesicus fuscus) inhabiting a chemically complex urban landscape. Our objective was to quantify population-level isotopic variation and test for evidence of resource specialization by individuals. Bats were sampled over 3 annual molt cycles at maternity roosts in buildings and variance components analysis was used to test whether intraindividual isotopic variation among molts differed from interindividual variation, after controlling for year and roost-group effects. Consistent with prior evidence that E. fuscus is opportunistic in its habitat use and foraging at the population level, we observed wide population-level variation for all isotopes. This variation likely reflects the chemical complexity of the urban landscape studied. However, isotopic variation among years within marked individuals was lower than variation among marked individuals within year for all isotopes, and carbon signatures indicated resource specialization by roost groups and individuals. This is the 1st study to examine variation in stable isotope ratios of individual wild bats over multiple years. Although our results suggest this population tends toward opportunistic habitat use or prey selection, or both, during molt periods, results also indicate that individuals and groups of bats composing the population might be habitat or dietary specialists—a novel finding for insectivorous bats.

Long working hours and sickness absence-a fixed effects design.

PubMed

Bernstrøm, Vilde Hoff

2018-05-02

While long working hours seem to lead to impaired health, several studies have also shown that long working hours are related to lower levels of sickness absence. Previous studies on the relationship between long working hours and sickness absence have compared those who work long hours to those who do not, looking only at between-individual correlations. Those results might therefore reflect relatively stable differences between employees who typically work long hours and employees who typically do not. The aim of the present study is to examine within-individual correlations between long working hours and sickness absence. Records from the Human Resources department in a large Norwegian hospital from 2012 to 2015 provided objective data on both working hours and sickness absence. Two analyses were performed: a prospective cohort analysis to replicate the results from previous between-individual analyses and a second analysis of within-individual correlations using a fixed effect design. In line with existing research, both between-individual and within-individual analyses showed a negative relationship between long working hours (> 48 h/week) and short-term sickness absence (1-8 days) and no significant difference in incidence of long-term sickness absence (> 8 days). The results indicate that the negative relationship between long working hours and sickness absence is not due only to relatively stable individual differences between those who typically work long hours and those who do not. The results from both analyses therefore still contrast with previous research showing a negative relationship between long working hours and other health indicators.

Ontogenetic and Among-Individual Variation in Foraging Strategies of Northeast Pacific White Sharks Based on Stable Isotope Analysis

PubMed Central

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 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 variation within a white shark population. PMID:23028766

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

USGS Publications Warehouse

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 variation within a white shark population.

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

PubMed

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 individual dietary variation within a white shark population.

A distinct section of the Early Bronze Age society? Stable isotope investigations of burials in settlement pits and multiple inhumations of the Únětice culture in central Germany.

PubMed

Knipper, Corina; Fragata, Matthias; Nicklisch, Nicole; Siebert, Angelina; Szécsényi-Nagy, Anna; Hubensack, Vera; Metzner-Nebelsick, Carola; Meller, Harald; Alt, Kurt W

2016-03-01

Inhumations in so-called settlement pits and multiple interments are subordinate burial practices of the Early Bronze Age Únětice culture in central Germany (2200-1700/1650 BC). The majority of the Únětice population was entombed as single inhumations in rectangular grave pits with a normative position of the body. The goal of the study was to test archaeological hypotheses that the deviant burials may represent socially distinct or nonlocal individuals. The study comprised up to two teeth and one bone each of 74 human individuals from eight sites and faunal comparative samples. The inhumations included regular, deviant burials in so-called settlement or storage pits, and multiple burials. We investigated radiogenic strontium isotope compositions of tooth enamel ((87) Sr/(86) Sr) and light stable isotope ratios of carbon and nitrogen of bone collagen (δ(13) C, δ(15) N) aiming at the disclosure of residential changes and dietary patterns. Site-specific strontium isotope data ranges mirror different geological properties including calcareous bedrock, loess, and glacial till. Independent from burial types, they disclose low portions of nonlocal individuals of up to some 20% at the individual sites. The light stable isotope ratios of burials in settlement pits and rectangular graves overlap widely and indicate highly similar dietary habits. The analytical results let to conclude that inhumations in settlement pits and multiple burials were two of the manifold burial practices of the Early Bronze Age. The selection criteria of the individuals for the different forms of inhumation remained undisclosed. © 2015 Wiley Periodicals, Inc.

Inter-individual differences in trait negative affect moderate cortisol's effects on memory formation: preliminary findings from two studies.

PubMed

Abercrombie, Heather C; Wirth, Michelle M; Hoks, Roxanne M

2012-05-01

Acute emotional arousal moderates the effects of cortisol on memory. However, it is currently unknown how stable inter-individual differences (i.e., traits) moderate cortisol's effects on memory. In two studies using within-subjects designs - 31 healthy males in Study 1 and 42 healthy subjects (22 female) in Study 2 - we measured trait negative affect (NA) and presented emotional and neutral pictures. In Study 1, we manipulated endogenous cortisol levels using a speech stressor following encoding. In Study 2, using a randomized placebo-controlled design, we pharmacologically manipulated cortisol levels prior to encoding (0.1mg/kg hydrocortisone vs. saline infused over 30min). Free recall for pictures was subsequently assessed. Trait NA repeatedly moderated the relationship between cortisol and memory formation. Findings suggested the speculative conclusion that the direction of effects may vary by sex. In males, cortisol was related to memory facilitation in subjects with lower Trait NA. Conversely, females with higher Trait NA showed greater cortisol-related increases in memory. Trait NA may be a stable inter-individual difference predicting neurocognitive effects of cortisol during stressors. Copyright © 2011 Elsevier Ltd. All rights reserved.

Detection of stable community structures within gut microbiota co-occurrence networks from different human populations.

PubMed

Jackson, Matthew A; Bonder, Marc Jan; Kuncheva, Zhana; Zierer, Jonas; Fu, Jingyuan; Kurilshikov, Alexander; Wijmenga, Cisca; Zhernakova, Alexandra; Bell, Jordana T; Spector, Tim D; Steves, Claire J

2018-01-01

Microbes in the gut microbiome form sub-communities based on shared niche specialisations and specific interactions between individual taxa. The inter-microbial relationships that define these communities can be inferred from the co-occurrence of taxa across multiple samples. Here, we present an approach to identify comparable communities within different gut microbiota co-occurrence networks, and demonstrate its use by comparing the gut microbiota community structures of three geographically diverse populations. We combine gut microbiota profiles from 2,764 British, 1,023 Dutch, and 639 Israeli individuals, derive co-occurrence networks between their operational taxonomic units, and detect comparable communities within them. Comparing populations we find that community structure is significantly more similar between datasets than expected by chance. Mapping communities across the datasets, we also show that communities can have similar associations to host phenotypes in different populations. This study shows that the community structure within the gut microbiota is stable across populations, and describes a novel approach that facilitates comparative community-centric microbiome analyses.

Biological variation, reference change value (RCV) and minimal important difference (MID) of inspiratory muscle strength (PImax) in patients with stable chronic heart failure.

PubMed

Täger, Tobias; Schell, Miriam; Cebola, Rita; Fröhlich, Hanna; Dösch, Andreas; Franke, Jennifer; Katus, Hugo A; Wians, Frank H; Frankenstein, Lutz

2015-10-01

Despite the widespread application of measurements of respiratory muscle force (PImax) in clinical trials there is no data on biological variation, reference change value (RCV), or the minimal important difference (MID) for PImax irrespective of the target cohort. We addressed this issue for patients with chronic stable heart failure. From the outpatients' clinic of the University of Heidelberg we retrospectively selected three groups of patients with stable systolic chronic heart failure (CHF). Each group had two measurements of PImax: 90 days apart in Group A (n = 25), 180 days apart in Group B (n = 93), and 365 days apart in Group C (n = 184). Stability was defined as (a) no change in NYHA class between visits and (b) absence of cardiac decompensation 3 months prior, during, and 3 months after measurements. For each group, we determined within-subject (CVI), between-subject (CVG), and total (CVT) coefficient of variation (CV), the index of individuality (II), RCV, reliability coefficient, and MID of PImax. CVT was 8.7, 7.5, and 6.9 % for groups A, B, and C, respectively. The II and RCV were 0.21, 0.20, 0.16 and 13.6, 11.6, 10.8 %, respectively. The reliability coefficient and MID were 0.83, 0.87, 0.88 and 1.44, 1.06, 1.12 kPa, respectively. Results were similar between age, gender, and aetiology subgroups. In patients with stable CHF, measurements of PImax are highly stable for intervals up to 1 year. The low values for II suggest that evaluation of change in PImax should be performed on an individual (per patient) basis. Individually significant change can be assumed beyond 14 % (RCV) or 1.12 kPa (MID).

The Stability of Social Desirability: A Latent Change Analysis.

PubMed

Haberecht, Katja; Schnuerer, Inga; Gaertner, Beate; John, Ulrich; Freyer-Adam, Jennis

2015-08-01

Social desirability has been shown to be stable in samples with higher school education. However, little is known about the stability of social desirability in more heterogeneous samples differing in school education. This study aimed to investigate the stability of social desirability and which factors predict interindividual differences in intraindividual change. As part of a randomized controlled trial, 1,243 job seekers with unhealthy alcohol use were systematically recruited at three job agencies. A total of 1,094 individuals (87.8%) participated in at least one of two follow-ups (6 and 15 months after baseline) and constitute this study's sample. The Social Desirability Scale-17 was applied. Two latent change models were conducted: Model 1 tested for interindividual differences in intraindividual change of social desirability between both follow-ups; Model 2 included possible predictors (age, sex, education, current employment status) of interindividual differences in intraindividual change. Model 1 revealed a significant decrease of social desirability over time. Model 2 revealed school education to be the only significant predictor of change. These findings indicate that stability of social desirability may depend on school education. It may not be as stable in individuals with higher school education as in individuals with lower education. © 2014 Wiley Periodicals, Inc.

Latent trait cortisol (LTC) during pregnancy: Composition, continuity, change, and concomitants.

PubMed

Giesbrecht, Gerald F; Bryce, Crystal I; Letourneau, Nicole; Granger, Douglas A

2015-12-01

Individual differences in the activity of the hypothalamic pituitary adrenal (HPA) axis are often operationalized using summary measures of cortisol that are taken to represent stable individual differences. Here we extend our understanding of a novel latent variable approach to latent trait cortisol (LTC) as a measure of trait-like HPA axis function during pregnancy. Pregnant women (n=380) prospectively collected 8 diurnal saliva samples (4 samples/day, 2 days) within each trimester. Saliva was assayed for cortisol. Confirmatory factor analyses were used to fit LTC models to early morning and daytime cortisol. For individual trimester data, only the daytime LTC models had adequate fit. These daytime LTC models were strongly correlated between trimesters and stable over pregnancy. Daytime LTC was unrelated to the cortisol awakening response and the daytime slope but strongly correlated with the area under the curve from ground. The findings support the validity of LTC as a measure of cortisol during pregnancy and suggest that it is not affected by pregnancy-related changes in HPA axis function. Copyright © 2015 Elsevier Ltd. All rights reserved.

Routes of Motivation: Stable Psychological Dispositions Are Associated with Dynamic Changes in Cortico-Cortical Functional Connectivity

PubMed Central

Viola, Vanda; Tosoni, Annalisa; Kruglanski, Arie W.; Galati, Gaspare; Mannetti, Lucia

2014-01-01

The present study provides a neurobiological framework to the theory of epistemic motivation that has been extensively studied for the last three decades in the domain of social cognition. Epistemic motivations affect the way people generate and validate hypotheses, and ultimately form and modify knowledge. Strong dispositional measures such as need for cognitive closure (NCC), the desire for a quick firm answer (any answer) to a question, show gross and stable inter-individual differences. The cognitive mechanisms and neural underpinnings of such differences, however, remain largely unexplored. Here we show that high (compared to low) levels of NCC, measured with need for cognitive closure scale, are associated with reduced online adjustment in cognitive control, as indexed by behavioral conflict adaptation. This behavioral effect is mediated by dynamic changes in cortico-cortical functional connectivity between prefrontal regions involved in conflict monitoring and implementation of cognitive control. In particular, these regions show increased functional connectivity after exposure to conflict in low but not high NCC individuals. These results demonstrate that the level of flexibility of functional cortico-cortical connections can mediate stable psychological dispositions. PMID:24892718

Individual Morphological Brain Network Construction Based on Multivariate Euclidean Distances Between Brain Regions.

PubMed

Yu, Kaixin; Wang, Xuetong; Li, Qiongling; Zhang, Xiaohui; Li, Xinwei; Li, Shuyu

2018-01-01

Morphological brain network plays a key role in investigating abnormalities in neurological diseases such as mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, most of the morphological brain network construction methods only considered a single morphological feature. Each type of morphological feature has specific neurological and genetic underpinnings. A combination of morphological features has been proven to have better diagnostic performance compared with a single feature, which suggests that an individual morphological brain network based on multiple morphological features would be beneficial in disease diagnosis. Here, we proposed a novel method to construct individual morphological brain networks for two datasets by calculating the exponential function of multivariate Euclidean distance as the evaluation of similarity between two regions. The first dataset included 24 healthy subjects who were scanned twice within a 3-month period. The topological properties of these brain networks were analyzed and compared with previous studies that used different methods and modalities. Small world property was observed in all of the subjects, and the high reproducibility indicated the robustness of our method. The second dataset included 170 patients with MCI (86 stable MCI and 84 progressive MCI cases) and 169 normal controls (NC). The edge features extracted from the individual morphological brain networks were used to distinguish MCI from NC and separate MCI subgroups (progressive vs. stable) through the support vector machine in order to validate our method. The results showed that our method achieved an accuracy of 79.65% (MCI vs. NC) and 70.59% (stable MCI vs. progressive MCI) in a one-dimension situation. In a multiple-dimension situation, our method improved the classification performance with an accuracy of 80.53% (MCI vs. NC) and 77.06% (stable MCI vs. progressive MCI) compared with the method using a single feature. The results indicated that our method could effectively construct an individual morphological brain network based on multiple morphological features and could accurately discriminate MCI from NC and stable MCI from progressive MCI, and may provide a valuable tool for the investigation of individual morphological brain networks.

Childhood Family Structure and Intergenerational Income Mobility in the United States.

PubMed

Bloome, Deirdre

2017-04-01

The declining prevalence of two-parent families helped increase income inequality over recent decades. Does family structure also condition how economic (dis)advantages pass from parents to children? If so, shifts in the organization of family life may contribute to enduring inequality between groups defined by childhood family structure. Using National Longitudinal Survey of Youth data, I combine parametric and nonparametric methods to reveal how family structure moderates intergenerational income mobility in the United States. I find that individuals raised outside stable two-parent homes are much more mobile than individuals from stable two-parent families. Mobility increases with the number of family transitions but does not vary with children's time spent coresiding with both parents or stepparents conditional on a transition. However, this mobility indicates insecurity, not opportunity. Difficulties maintaining middle-class incomes create downward mobility among people raised outside stable two-parent homes. Regardless of parental income, these people are relatively likely to become low-income adults, reflecting a new form of perverse equality. People raised outside stable two-parent families are also less likely to become high-income adults than people from stable two-parent homes. Mobility differences account for about one-quarter of family-structure inequalities in income at the bottom of the income distribution and more than one-third of these inequalities at the top.

Individual Differences in Resting Corticospinal Excitability Are Correlated with Reaction Time and GABA Content in Motor Cortex

PubMed Central

Ivry, Richard B.

2017-01-01

Individuals differ in the intrinsic excitability of their corticospinal pathways and, perhaps more generally, their entire nervous system. At present, we have little understanding of the mechanisms underlying these differences and how variation in intrinsic excitability relates to behavior. Here, we examined the relationship between individual differences in intrinsic corticospinal excitability, local cortical GABA levels, and reaction time (RT) in a group of 20 healthy human adults. We measured corticospinal excitability at rest with transcranial magnetic stimulation, local concentrations of basal GABA with magnetic resonance spectroscopy, and RT with a behavioral task. All measurements were repeated in two separate sessions, and tests of reliability confirmed the presence of stable individual differences. There was a negative correlation between corticospinal excitability and RT, such that larger motor-evoked potentials (MEPs) measured at rest were associated with faster RTs. Interestingly, larger MEPs were associated with higher levels of GABA in M1, but not in three other cortical regions. Together, these results suggest that individuals with more excitable corticospinal pathways are faster to initiate planned responses and have higher levels of GABA within M1, possibly to compensate for a more excitable motor system. SIGNIFICANCE STATEMENT This study brings together physiological, behavioral, and neurochemical evidence to examine variability in the excitability of the human motor system. Previous work has focused on state-based factors (e.g., preparedness, uncertainty), with little attention given to the influence of inherent stable characteristics. Here, we examined how the excitability of the motor system relates to reaction time and the regional content of the inhibitory neurotransmitter GABA. Importantly, motor pathway excitability and GABA concentrations were measured at rest, outside a task context, providing assays of intrinsic properties of the individuals. Individuals with more excitable motor pathways had faster reaction times and, paradoxically, higher concentrations of GABA. We propose that greater GABA capacity in the motor cortex counteracts an intrinsically more excitable motor system. PMID:28179557

Investigation into the Individualized Treatment of Traditional Chinese Medicine through a Series of N-of-1 Trials

PubMed Central

Yang, Peilan; Wang, Jie; Wu, Yingen; Zi, Suna; Tang, Jie; Wang, Zhenwei

2018-01-01

Purpose To compare the efficacy of individualized herbal decoction with standard decoction for patients with stable bronchiectasis through N-of-1 trials. Methods We conducted a single center N-of-1 trials in 17 patients with stable bronchiectasis. Each N-of-1 trial contains three cycles. Each cycle is divided into two 4-week intervention including individualized decoction and fixed decoction (control). The primary outcome was patient self-reported symptoms scores on a 1–7 point Likert scale. Secondary outcomes were 24-hour sputum volume and CAT scores. Results Among 14 completed trials, five showed that the individualized decoction was statistically better than the control decoction on symptom scores (P < 0.05) but was not clinically significant. The group data of all the trials showed that individualized decoction was superior to control decoction on symptom scores (2.13 ± 0.58 versus 2.30 ± 0.65, P = 0.002, mean difference and 95% CI: 0.18 (0.10, 0.25)), 24 h sputum volume (P = 0.009), and CAT scores (9.69 ± 4.89 versus 11.64 ± 5.59, P = 0.013, mean difference and 95% CI: 1.95 (1.04, 2.86)) but not clinically significant. Conclusion Optimizing the combined analysis of individual and group data and the improvement of statistical models may make contribution in establishing a method of evaluating clinical efficacy in line with the characteristics of traditional Chinese medicine individual diagnosis and treatment. PMID:29552084

Using stable isotopes to investigate individual diet specialization in California sea otters (Enhydra lutris nereis)

USGS Publications Warehouse

Newsome, S.D.; Tinker, M.T.; Monson, Daniel H.; Oftedal, O.T.; Ralls, K.; Staedler, M.M.; Fogel, M.L.; Estes, J.A.

2009-01-01

Differences in diet composition among conspecifics (dietary specialization) have been documented across a broad range of taxonomic groups and habitats, and such variation at the individual level is increasingly recognized as an important component of diversity in trophic interactions. Accurate identification of individual dietary specialization, however, requires longitudinal dietary records that are labor-intensive and cost-prohibitive to obtain for many species. Here we explore the use of stable isotopes (δ13C and δ15N) as a promising technique for detecting and quantifying patterns of individual dietary specialization. Southern sea otters (Enhydra lutris nereis) offer a unique opportunity for testing this approach because (1) they consume a wide variety of prey that span multiple trophic levels, habitats, and ecologically defined functional groups; and (2) individual diet specialization can be validated with existing observational data. We analyzed the isotopic composition of sea otter vibrissae (n = 31) in order to characterize inter- and intra-individual variation in sea otter diets at Monterey Bay, California, USA. At the population level, sea otters showed substantial variation in both δ13C and δ15N values, occupying nearly all of the “isotopic space” created by the diversity of isotopic signatures of potential prey taxa. Most of the variation in sea otter vibrissae was accounted for by differences between individuals, with much less contributed by within-individual variation. A majority of sea otters (∼80%) showed relatively little temporal variability in isotopic composition, suggesting that the proportional composition of most individuals' diets is relatively constant over time; a few individuals (∼20%) exhibited a high degree of intra-vibrissa isotopic variability, suggesting seasonal shifts in diet composition. These results and our interpretation of them were supported by long-term observational data on the diets of radio-tagged sea otters from the same population (n = 23). Our results demonstrate that stable isotopes can provide an efficient tool for measuring individual- and population-level dietary breadth and may be useful for studying populations where longitudinal data on individuals would otherwise be impossible to acquire. This will be critical for examining the causes and consequences of dietary variation within and among consumer populations, thereby improving our understanding of these important ecological and evolutionary processes at the community level.

Stable Isotope and Trace Element Studies on Gladiators and Contemporary Romans from Ephesus (Turkey, 2nd and 3rd Ct. AD) - Implications for Differences in Diet

PubMed Central

Lösch, Sandra; Moghaddam, Negahnaz; Grossschmidt, Karl; Risser, Daniele U.; Kanz, Fabian

2014-01-01

The gladiator cemetery discovered in Ephesus (Turkey) in 1993 dates to the 2nd and 3rd century AD. The aim of this study is to reconstruct diverse diet, social stratification, and migration of the inhabitants of Roman Ephesus and the distinct group of gladiators. Stable carbon, nitrogen, and sulphur isotope analysis were applied, and inorganic bone elements (strontium, calcium) were determined. In total, 53 individuals, including 22 gladiators, were analysed. All individuals consumed C3 plants like wheat and barley as staple food. A few individuals show indication of consumption of C4 plants. The δ13C values of one female from the gladiator cemetery and one gladiator differ from all other individuals. Their δ34S values indicate that they probably migrated from another geographical region or consumed different foods. The δ15N values are relatively low in comparison to other sites from Roman times. A probable cause for the depletion of 15N in Ephesus could be the frequent consumption of legumes. The Sr/Ca-ratios of the gladiators were significantly higher than the values of the contemporary Roman inhabitants. Since the Sr/Ca-ratio reflects the main Ca-supplier in the diet, the elevated values of the gladiators might suggest a frequent use of a plant ash beverage, as mentioned in ancient texts. PMID:25333366

MHC odours are not required or sufficient for recognition of individual scent owners

PubMed Central

Hurst, Jane L; Thom, Michael D; Nevison, Charlotte M; Humphries, Richard E; Beynon, Robert J

2005-01-01

To provide information about specific depositors, scent marks need to encode a stable signal of individual ownership. The highly polymorphic major histocompatibility complex (MHC) influences scents and contributes to the recognition of close kin and avoidance of inbreeding when MHC haplotypes are shared. MHC diversity between individuals has also been proposed as a primary source of scents used in individual recognition. We tested this in the context of scent owner recognition among male mice, which scent mark their territories and countermark scents from other males. We examined responses towards urine scent according to the scent owner's genetic difference to the territory owner (MHC, genetic background, both and neither) or genetic match to a familiar neighbour. While urine of a different genetic background from the subject always stimulated greater scent marking than own, regardless of familiarity, MHC-associated odours were neither necessary nor sufficient for scent owner recognition and failed to stimulate countermarking. Urine of a different MHC type to the subject stimulated increased investigation only when this matched both the MHC and genetic background of a familiar neighbour. We propose an associative model of scent owner recognition in which volatile scent profiles, contributed by both fixed genetic and varying non-genetic factors, are learnt in association with a stable involatile ownership signal provided by other highly polymorphic urine components. PMID:15906464

Misleading first impressions: different for different facial images of the same person.

PubMed

Todorov, Alexander; Porter, Jenny M

2014-07-01

Studies on first impressions from facial appearance have rapidly proliferated in the past decade. Almost all of these studies have relied on a single face image per target individual, and differences in impressions have been interpreted as originating in stable physiognomic differences between individuals. Here we show that images of the same individual can lead to different impressions, with within-individual image variance comparable to or exceeding between-individuals variance for a variety of social judgments (Experiment 1). We further show that preferences for images shift as a function of the context (e.g., selecting an image for online dating vs. a political campaign; Experiment 2), that preferences are predictably biased by the selection of the images (e.g., an image fitting a political campaign vs. a randomly selected image; Experiment 3), and that these biases are evident after extremely brief (40-ms) presentation of the images (Experiment 4). We discuss the implications of these findings for studies on the accuracy of first impressions. © The Author(s) 2014.

Contributions of temperament to buffering and sensitization processes in children's development.

PubMed

Wachs, Theodore D

2006-12-01

Temperament refers to relatively stable, early appearing, biologically rooted individual differences in behavioral traits. Individual differences in temperament are multidetermined encompassing both biological and experiential influences. Evidence indicates that certain temperament traits, such as impulsivity, inhibition, and negative emotionality, can serve as developmental risk factors. Evidence also indicates that other temperament traits, such as flexible self-regulation, sociability, and task orientation, can serve to increase children's resilience. Five potential mechanisms through which individual differences in temperament can increase vulnerability or facilitate resilience are presented: (1) Differential treatment of children with different temperaments by caregivers or teachers (reactive covariance). (2) Children with different temperament styles seeking out environments that may increase risk or promote resilience (active covariance). (3) Goodness or poorness of fit between child temperament characteristics and environmental demands. (4) Children with different temperaments reacting to similar levels or types of stress in different ways. (5) Different coping strategies used by children with different temperaments.

Understanding individual differences in representational abstraction: The role of working memory capacity.

PubMed

Stukken, Loes; Van Rensbergen, Bram; Vanpaemel, Wolf; Storms, Gert

2016-10-01

Several studies have reported differences in categorization strategies among participants: some learn a category by making abstraction across the category members while others use a memorization strategy. Despite the prevalence of these differences, little attention has been paid to investigating what influences some to use an abstraction strategy and others a memorization strategy. The current study had two goals: in a first experiment we investigated whether these differences were stable across time, using the parallel form method often used in psychometric research, and in a second experiment we investigated whether the individual differences in categorization strategy were related to working memory capacity. We used a modelling strategy, in which we not only focused on full abstraction and memorization strategies, but also on intermediate strategies in which some category members are abstracted and others are not. The first study revealed that the individual abstraction strategy of individual participants in two different experiments, performed at different times, correlate significantly, and second study showed that these individual differences were related to the working memory capacity of the participants. Copyright © 2016 Elsevier B.V. All rights reserved.

[A new strategy for Chinese medicine processing technologies: coupled with individuation processed and cybernetics].

PubMed

Zhang, Ding-kun; Yang, Ming; Han, Xue; Lin, Jun-zhi; Wang, Jia-bo; Xiao, Xiao-he

2015-08-01

The stable and controllable quality of decoction pieces is an important factor to ensure the efficacy of clinical medicine. Considering the dilemma that the existing standardization of processing mode cannot effectively eliminate the variability of quality raw ingredients, and ensure the stability between different batches, we first propose a new strategy for Chinese medicine processing technologies that coupled with individuation processed and cybernetics. In order to explain this thinking, an individual study case about different grades aconite is provided. We hope this strategy could better serve for clinical medicine, and promote the inheritance and innovation of Chinese medicine processing skills and theories.

Individual specialization in diet by a generalist marine predator reflects specialization in foraging behaviour.

PubMed

Woo, Kerry J; Elliott, Kyle Hamish; Davidson, Melissa; Gaston, Anthony J; Davoren, Gail K

2008-11-01

1. We studied chick diet in a known-age, sexed population of a long-lived seabird, the Brünnich's guillemot (Uria lomvia), over 15 years (N = 136; 1993-2007) and attached time-depth-temperature recorders to examine foraging behaviour in multiple years (N = 36; 2004-07). 2. Adults showed specialization in prey fed to offspring, described by multiple indices calculated over 15 years: 27% of diet diversity was attributable to among-individual variation (within-individual component of total niche width = 0.73); average similarity of an individual's diet to the overall diet was 65% (mean proportional similarity between individuals and population = 0.65); diet was significantly more specialized than expected for 70% of individuals (mean likelihood = 0.53). These indices suggest higher specialization than the average for an across-taxa comparison of 49 taxa. 3. Foraging behaviour varied along three axes: flight time, dive depth and dive shape. Individuals showed specialized individual foraging behaviour along each axis. These foraging strategies were reflected in the prey type delivered to their offspring and were maintained over scales of hours to years. 4. Specialization in foraging behaviour and diet was greater over short time spans (hours, days) than over long time spans (years). Regardless of sex or age, the main component of variation in foraging behaviour and chick diet was between individuals. 5. Plasma stable isotope values were similar across years, within a given individual, and variance was low relative to that expected from prey isotope values, suggesting adult diet specialized across years. Stable isotope values were similar among individuals that fed their nestlings similar prey items and there was no difference in trophic level between adults and chicks. We suggest that guillemots specialize on a single foraging strategy regardless of whether chick-provisioning and self-feeding. With little individual difference in body mass and physiology, specialization likely represents learning and memorizing optimal feeding locations and behaviours. 6. There was no difference in survival or reproductive success between specialists and generalists, suggesting these are largely equivalent strategies in terms of evolutionary fitness, presumably because different strategies were advantageous at different levels of prey abundance or predictability. The development of individual specialization may be an important precursor to diversification among seabirds.

Self-esteem Is Mostly Stable Across Young Adulthood: Evidence from Latent STARTS Models.

PubMed

Wagner, Jenny; Lüdtke, Oliver; Trautwein, Ulrich

2016-08-01

How stable is self-esteem? This long-standing debate has led to different conclusions across different areas of psychology. Longitudinal data and up-to-date statistical models have recently indicated that self-esteem has stable and autoregressive trait-like components and state-like components. We applied latent STARTS models with the goal of replicating previous findings in a longitudinal sample of young adults (N = 4,532; Mage  = 19.60, SD = 0.85; 55% female). In addition, we applied multigroup models to extend previous findings on different patterns of stability for men versus women and for people with high versus low levels of depressive symptoms. We found evidence for the general pattern of a major proportion of stable and autoregressive trait variance and a smaller yet substantial amount of state variance in self-esteem across 10 years. Furthermore, multigroup models suggested substantial differences in the variance components: Females showed more state variability than males. Individuals with higher levels of depressive symptoms showed more state and less autoregressive trait variance in self-esteem. Results are discussed with respect to the ongoing trait-state debate and possible implications of the group differences that we found in the stability of self-esteem. © 2015 Wiley Periodicals, Inc.

Consistent individual differences in the social phenotypes of wild great tits, Parus major

PubMed Central

Aplin, L.M.; Firth, J.A.; Farine, D.R.; Voelkl, B.; Crates, R.A.; Culina, A.; Garroway, C.J.; Hinde, C.A.; Kidd, L.R.; Psorakis, I.; Milligan, N.D.; Radersma, R.; Verhelst, B.L.; Sheldon, B.C.

2015-01-01

Despite growing interest in animal social networks, surprisingly little is known about whether individuals are consistent in their social network characteristics. Networks are rarely repeatedly sampled; yet an assumption of individual consistency in social behaviour is often made when drawing conclusions about the consequences of social processes and structure. A characterization of such social phenotypes is therefore vital to understanding the significance of social network structure for individual fitness outcomes, and for understanding the evolution and ecology of individual variation in social behaviour more broadly. Here, we measured foraging associations over three winters in a large PIT-tagged population of great tits, and used a range of social network metrics to quantify individual variation in social behaviour. We then examined repeatability in social behaviour over both short (week to week) and long (year to year) timescales, and investigated variation in repeatability across age and sex classes. Social behaviours were significantly repeatable across all timescales, with the highest repeatability observed in group size choice and unweighted degree, a measure of gregariousness. By conducting randomizations to control for the spatial and temporal distribution of individuals, we further show that differences in social phenotypes were not solely explained by within-population variation in local densities, but also reflected fine-scale variation in social decision making. Our results provide rare evidence of stable social phenotypes in a wild population of animals. Such stable social phenotypes can be targets of selection and may have important fitness consequences, both for individuals and for their social-foraging associates. PMID:26512142

Airway clearance techniques for bronchiectasis.

PubMed

Lee, Annemarie L; Burge, Angela; Holland, Anne E

2013-05-31

People with non-cystic fibrosis bronchiectasis commonly experience chronic cough and sputum production and these features may be associated with progressive decline in clinical status. Airway clearance techniques (ACTs) are often prescribed to facilitate expectoration of sputum from the lungs, but the efficacy of these techniques in a stable clinical state or during an acute exacerbation of bronchiectasis is unclear. Primary: to determine the effects of ACTs on the rate of acute exacerbations, incidence of hospitalisation and health-related quality of life in individuals with acute and stable bronchiectasis.Secondary: to determine whether a) ACTs are safe for individuals with acute and stable bronchiectasis and b) ACTs have beneficial effects on physiology and symptoms in individuals with acute and stable bronchiectasis. We searched the Cochrane Airways Group Specialised Register of trials from inception to October 2012, PEDro in October 2012 and handsearched relevant journals. Randomised controlled parallel and cross-over trials that compared an ACT to no treatment, sham ACT or directed coughing in participants with bronchiectasis. We used standard methodological procedures expected by The Cochrane Collaboration. Five studies involving 51 participants met the inclusion criteria of the review, all of which were cross-over design. Four studies were on adults with stable bronchiectasis, and the other study was on clinically stable children with bronchiectasis. Three studies were single treatment sessions, two were longer-term studies. The interventions varied and some control groups received a sham intervention while others were inactive. The methodological quality of the studies was variable and the studies were not able to blind participants and personal. Heterogeneity between studies precluded these data from meta-analysis and the review was therefore narrative.One study on 20 adults comparing an airway oscillatory device with no treatment found no significant difference in the number of exacerbations at 12 weeks (low-quality evidence). No data were available to assess the impact of ACTs on the time to exacerbation, duration of, incidence of hospitalisation or total number of hospitalised days. The same study reported clinically significant improvements in health-related quality of life in both disease-specific and cough-related measures. While based on a small number of participants and the data were skewed, the median difference in the change in total St George's Respiratory Questionnaire (SGRQ) score over three months in this study was 8.5 units (P value = 0.005 (Wilcoxon), low-quality evidence). Two studies reported mean increases in volume of sputum expectorated with airway oscillatory devices in the short term of 8.4 mL (95% CI 3.4 to 13.4 mL) and in the long term of 3 mL (P value = 0.02), with no significant effect on lung function. One study reported an immediate reduction in pulmonary hyperinflation in adults with non-positive expiratory pressure (PEP) ACTs (difference in functional residual capacity (FRC) of 19%, P value < 0.05) and with airway oscillatory devices (difference in FRC of 30%, P value < 0.05) compared to no ACTs. A similar decrease in pulmonary hyperinflation (difference in FRC of 6%) was found in children using an airway oscillatory device for 3 months compared to sham therapy. No studies reported on the effects of gas exchange, people's symptoms or antibiotic usage. ACTs appear to be safe for individuals (adults and children) with stable bronchiectasis, where there may be improvements in sputum expectoration, selected measures of lung function and health-related quality of life. The role of these techniques in people with an acute exacerbation of bronchiectasis is unknown. In view of the chronic nature of bronchiectasis, more data are needed to establish the clinical value of ACTs over the short and long term on patient-important outcomes, including symptoms, on physiological outcomes which may clarify the rationale for each technique and on long-term parameters that impact on disease progression in individuals with stable bronchiectasis. This is necessary in order to provide further guidance of specific ACT prescription for people with bronchiectasis. It may also be important to establish the comparative effect of different types of ACTs in people with bronchiectasis.

Contextual and Developmental Differences in the Neural Architecture of Cognitive Control.

PubMed

Petrican, Raluca; Grady, Cheryl L

2017-08-09

Because both development and context impact functional brain architecture, the neural connectivity signature of a cognitive or affective predisposition may similarly vary across different ages and circumstances. To test this hypothesis, we investigated the effects of age and cognitive versus social-affective context on the stable and time-varying neural architecture of inhibition, the putative core cognitive control component, in a subsample ( N = 359, 22-36 years, 174 men) of the Human Connectome Project. Among younger individuals, a neural signature of superior inhibition emerged in both stable and dynamic connectivity analyses. Dynamically, a context-free signature emerged as stronger segregation of internal cognition (default mode) and environmentally driven control (salience, cingulo-opercular) systems. A dynamic social-affective context-specific signature was observed most clearly in the visual system. Stable connectivity analyses revealed both context-free (greater default mode segregation) and context-specific (greater frontoparietal segregation for higher cognitive load; greater attentional and environmentally driven control system segregation for greater reward value) signatures of inhibition. Superior inhibition in more mature adulthood was typified by reduced segregation in the default network with increasing reward value and increased ventral attention but reduced cingulo-opercular and subcortical system segregation with increasing cognitive load. Failure to evidence this neural profile after the age of 30 predicted poorer life functioning. Our results suggest that distinguishable neural mechanisms underlie individual differences in cognitive control during different young adult stages and across tasks, thereby underscoring the importance of better understanding the interplay among dispositional, developmental, and contextual factors in shaping adaptive versus maladaptive patterns of thought and behavior. SIGNIFICANCE STATEMENT The brain's functional architecture changes across different contexts and life stages. To test whether the neural signature of a trait similarly varies, we investigated cognitive versus social-affective context effects on the stable and time-varying neural architecture of inhibition during a period of neurobehavioral fine-tuning (age 22-36 years). Younger individuals with superior inhibition showed distinguishable context-free and context-specific neural profiles, evidenced in both static and dynamic connectivity analyses. More mature individuals with superior inhibition evidenced only context-specific profiles, revealed in the static connectivity patterns linked to increased reward or cognitive load. Delayed expression of this profile predicted poorer life functioning. Our results underscore the importance of understanding the interplay among dispositional, developmental, and contextual factors in shaping behavior. Copyright © 2017 the authors 0270-6474/17/377711-16$15.00/0.

Unique and Persistent Individual Patterns of Brain Activity Across Different Memory Retrieval Tasks

PubMed Central

Miller, Michael B.; Donovan, Christa-Lynn; Van Horn, John D.; German, Elaine; Sokol-Hessner, Peter; Wolford, George L.

2009-01-01

Fourteen subjects were scanned in two fMRI sessions separated by several months. During each session, subjects performed an episodic retrieval task, a semantic retrieval task, and a working memory task. We found that 1) despite extensive intersubject variability in the pattern of activity across the whole brain, individual activity patterns were stable over time, 2) activity patterns of the same individual performing different tasks were more similar than activity patterns of different individuals performing the same task, and 3) that individual differences in decision criterion on a recognition test predicted the degree of similarity between any two individuals’ patterns of brain activity, but individual differences in memory accuracy or similarity in structural anatomy did not. These results imply that the exclusive use of group maps may be ineffective in profiling the pattern of activations for a given task. This may be particularly true for a task like episodic retrieval, which is relatively strategic and can involve widely-distributed specialized processes that are peripheral to the actual retrieval of stored information. Further, these processes may be differentially engaged depending on individual differences in cognitive processing and/or physiology. PMID:19540922

Preschool Drawing and School Mathematics: The Nature of the Association

PubMed Central

Malanchini, M.; Tosto, M.G.; Garfield, V.; Czerwik, A.; Dirik, A.; Arden, R.; Malykh, S.

2016-01-01

The study examined the aetiology of individual differences in early drawing and of its longitudinal association with school mathematics. Participants (N = 14,760), members of the Twins Early Development Study, were assessed on their ability to draw a human figure, including number of features, symmetry and proportionality. Human figure drawing was moderately stable across six months (average r = .40). Individual differences in drawing at age 4½ were influenced by genetic (.21), shared environmental (.30) and non-shared environmental (.49) factors. Drawing was related to later (age 12) mathematical ability (average r = .24). This association was explained by genetic and shared environmental factors that also influenced general intelligence. Some genetic factors, unrelated to intelligence, also contributed to individual differences in drawing. PMID:27079561

Insular Activity during Passive Viewing of Aversive Stimuli Reflects Individual Differences in State Negative Affect

ERIC Educational Resources Information Center

Meriau, Katja; Wartenburger, Isabell; Kazzer, Philipp; Prehn, Kristin; Villringer, Arno; van der Meer, Elke; Heekeren, Hauke R.

2009-01-01

People differ with regard to how they perceive, experience, and express negative affect. While trait negative affect reflects a stable, sustained personality trait, state negative affect represents a stimulus limited and temporally acute emotion. So far, little is known about the neural systems mediating the relationship between negative affect…

Lifetime Stable isotopes profiles in whale earplug: assessment of foraging and migrations in the Northern Hemisphere

NASA Astrophysics Data System (ADS)

Mansouri, F.; Crain, D.; Winfield, Z.; Trumble, S.; Usenko, S.

2017-12-01

Whale earplugs, historically used for aging, were used to reconstruct lifetime stable isotope profiles for carbon (δ13C) and nitrogen (δ15N) for individual whales by delaminating lamina within the earplug. These stable isotope profile, which provide Continuous lifetime records of feeding, foraging ecology, and migration, were determined for 20 individuals from 4 baleen species including fin, minke, humpback, and blue whales spanning more than a century (1869 - 2014) using stable isotope analysis. Approximately 1 mg tissue from each lamina (n=1200) was analyzed for carbon and nitrogen stable isotope using continuous flow isotope ratio mass spectrometer (CF-IRMS). This research using whale earplugs have combined age estimates with stable isotope measurements to reconstruct lifetime foraging profiles with a 6-month resolution, providing an unprecedented opportunity to assess periods and trends in dietary fluctuations as well as migration between different foraging area which have distinct isotope values. Trends with these profiles suggest long-term changing in migration, while annual variability highlights seasonal fasting and feeding. Isotopic ratios were also used to identify subpopulations of Atlantic fin whales, which enabled us to assign unidentified humpback and minke whales to the Atlantic or Pacific Oceans. This historical archive of data provides us an unprecedented tool to assess long term marine ecosystem and subsequently marine organism transition to alternate foraging area and shed light on the whale's population status in the Northern hemisphere.

Tiwanaku influence and social inequality: A bioarchaeological, biogeochemical, and contextual analysis of the Larache cemetery, San Pedro de Atacama, Northern Chile.

PubMed

Torres-Rouff, Christina; Knudson, Kelly J; Pestle, William J; Stovel, Emily M

2015-12-01

To assess the relationship between the Tiwanaku polity and the individuals buried at the Middle Horizon (∼AD500-1000) cemetery of Larache in northern Chile, a site that has been singled out as a potential elite foreign enclave. We explore this association through the skeletal remains of 48 individuals interred at the cemetery of Larache using bioarchaeological, biogeochemical, and artifactual evidence. Data from cranial modification practices, violent injury, and the mortuary assemblage are used to explore culturally constructed elements of status and identity, radiogenic strontium isotope analyses provide us with a perspective on the geographic origins of these individuals, and stable carbon and nitrogen analyses allow discussion of paleodiet and access to resources. Radiogenic strontium isotope values show the presence of multiple first generation migrants at Larache. Stable carbon and nitrogen isotope data reveal significant differences among individuals. The mortuary context reveals a standard pattern for the oases but also includes a series of unusual burials with abundant gold and few other objects. Interestingly, both local and nonlocal individuals with different head shapes had access to the differentiated burial context; however nonlocal individuals appear to be the only ones with a heavily maize-based diet. Our evidence shows that Larache served as a burial place for a diverse, yet culturally integrated and potentially elite segment of the Atacameño population, but not a foreign enclave as had been postulated. © 2015 Wiley Periodicals, Inc.

Fractionation of metal stable isotopes by higher plants

USGS Publications Warehouse

Von Blanckenburg, F.; Von Wiren, N.; Guelke, M.; Weiss, D.J.; Bullen, T.D.

2009-01-01

Higher plants induce chemical reactions in the rhizosphere, facilitating metal uptake by roots. Fractionation of the isotopes in nutrients such as calcium, iron, magnesium, and zinc produces a stable isotope composition in the plants that generally differs from that of the growth medium. Isotope fractionation also occurs during transport of the metals within most plants, but its extent depends on plant species and on the metal, in particular, on the metal's redox state and what ligand it is bound to. The metal stable isotope variations observed in plants create an isotope signature of life at the Earth's surface, contributing substantially to our understanding of metal cycling processes in the environment and in individual organisms.

Two-year stability of individual differences in (para)sympathetic and HPA-axis responses to public speaking in childhood and adolescence.

PubMed

van den Bos, Esther; Westenberg, P Michiel

2015-03-01

Long-term stability of individual differences in stress responses has repeatedly been demonstrated in adults, but few studies have investigated the development of stability in adolescence. The present study was the first to investigate the stability of individual differences in heart rate, parasympathetic (RMSSD, pNN50, HF), sympathetic (LF/HF, SC), and HPA-axis (salivary cortisol) responses in a youth sample (8-19 years). Responses to public speaking were measured twice over 2 years. Stability was moderate for absolute responses and task delta responses of HR, RMSSD, pNN50, and HF. Stability was lower for SC and task delta responses of LF/HF and cortisol. Anticipation delta responses showed low stability for HR and cortisol. The latter was moderated by age or puberty, so that individual differences were more stable in more mature individuals. The results support the suggestion that stress responses may be reset during adolescence, but only for the HPA axis. © 2014 Society for Psychophysiological Research.

Risk, resources and state-dependent adaptive behavioural syndromes

PubMed Central

Luttbeg, Barney; Sih, Andrew

2010-01-01

Many animals exhibit behavioural syndromes—consistent individual differences in behaviour across two or more contexts or situations. Here, we present adaptive, state-dependent mathematical models for analysing issues about behavioural syndromes. We find that asset protection (where individuals with more ‘assets’ tend be more cautious) and starvation avoidance, two state-dependent mechanisms, can explain short-term behavioural consistency, but not long-term stable behavioural types (BTs). These negative-feedback mechanisms tend to produce convergence in state and behaviour over time. In contrast, a positive-feedback mechanism, state-dependent safety (where individuals with higher energy reserves, size, condition or vigour are better at coping with predators), can explain stable differences in personality over the long term. The relative importance of negative- and positive-feedback mechanisms in governing behavioural consistency depends on environmental conditions (predation risk and resource availability). Behavioural syndromes emerge more readily in conditions of intermediate ecological favourability (e.g. medium risk and medium resources, or high risk and resources, or low risk and resources). Under these conditions, individuals with higher initial state maintain a tendency to be bolder than individuals that start with low initial state; i.e. later BT is determined by state during an early ‘developmental window’. In contrast, when conditions are highly favourable (low risk, high resources) or highly unfavourable (high risk, low resources), individuals converge to be all relatively bold or all relatively cautious, respectively. In those circumstances, initial differences in BT are not maintained over the long term, and there is no early developmental window where initial state governs later BT. The exact range of ecological conditions favouring behavioural syndromes depends also on the strength of state-dependent safety. PMID:21078650

Integration of stable isotope and trace contaminant concentration for enhanced forensic acetone discrimination.

PubMed

Moran, James J; Ehrhardt, Christopher J; Wahl, Jon H; Kreuzer, Helen W; Wahl, Karen L

2013-11-15

We analyzed 21 neat acetone samples from 15 different suppliers to demonstrate the utility of a coupled stable isotope and trace contaminant strategy for distinguishing forensically-relevant samples. By combining these two pieces of orthogonal data we could discriminate all of the acetones that were produced by the 15 different suppliers. Using stable isotope ratios alone, we were able to distinguish 8 acetone samples, while the remaining 13 fell into four clusters with highly similar signatures. Adding trace chemical contaminant information enhanced discrimination to 13 individual acetones with three residual clusters. The acetones within each cluster shared a common manufacturer and might, therefore, not be expected to be resolved. The data presented here demonstrates the power of combining orthogonal data sets to enhance sample fingerprinting and highlights the role disparate data could play in future forensic investigations. © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Childhood Family Structure and Intergenerational Income Mobility in the United States

PubMed Central

2018-01-01

The declining prevalence of two-parent families helped increase income inequality over recent decades. Does family structure also condition how economic (dis)advantages pass from parents to children? If so, shifts in the organization of family life may contribute to enduring inequality between groups defined by childhood family structure. Using National Longitudinal Survey of Youth data, I combine parametric and nonparametric methods to reveal how family structure moderates intergenerational income mobility in the United States. I find that individuals raised outside stable two-parent homes are much more mobile than individuals from stable two-parent families. Mobility increases with the number of family transitions but does not vary with children’s time spent coresiding with both parents or stepparents conditional on a transition. However, this mobility indicates insecurity, not opportunity. Difficulties maintaining middle-class incomes create downward mobility among people raised outside stable two-parent homes. Regardless of parental income, these people are relatively likely to become low-income adults, reflecting a new form of perverse equality. People raised outside stable two-parent families are also less likely to become high-income adults than people from stable two-parent homes. Mobility differences account for about one-quarter of family-structure inequalities in income at the bottom of the income distribution and more than one-third of these inequalities at the top. PMID:28315158

The cognitive-behavioral system of leadership: cognitive antecedents of active and passive leadership behaviors

PubMed Central

Dóci, Edina; Stouten, Jeroen; Hofmans, Joeri

2015-01-01

In the present paper, we propose a cognitive-behavioral understanding of active and passive leadership. Building on core evaluations theory, we offer a model that explains the emergence of leaders’ active and passive behaviors, thereby predicting stable, inter-individual, as well as variable, intra-individual differences in both types of leadership behavior. We explain leaders’ stable behavioral tendencies by their fundamental beliefs about themselves, others, and the world (core evaluations), while their variable, momentary behaviors are explained by the leaders’ momentary appraisals of themselves, others, and the world (specific evaluations). By introducing interactions between the situation the leader enters, the leader’s beliefs, appraisals, and behavior, we propose a comprehensive system of cognitive mechanisms that underlie active and passive leadership behavior. PMID:26441721

Bilateral improvements in lower extremity function after unilateral balance training in individuals with chronic ankle instability.

PubMed

Hale, Sheri A; Fergus, Andrea; Axmacher, Rachel; Kiser, Kimberly

2014-01-01

Bilateral improvements in postural control have been reported among individuals with acute lateral ankle sprains and individuals with chronic ankle instability (CAI) when only the unstable ankle is rehabilitated. We do not know if training the stable ankle will improve function on the unstable side. To explore the effects of a unilateral balance-training program on bilateral lower extremity balance and function in individuals with CAI when only the stable limb is trained. Cohort study. University clinical research laboratory. A total of 34 volunteers (8 men, 26 women; age = 24.32 ± 4.95 years, height = 167.01 ± 9.45 cm, mass = 77.54 ± 23.76 kg) with CAI were assigned to the rehabilitation (n = 17) or control (n = 17) group. Of those, 27 (13 rehabilitation group, 14 control group) completed the study. Balance training twice weekly for 4 weeks. Foot and Ankle Disability Index (FADI), FADI Sport (FADI-S), Star Excursion Balance Test, and Balance Error Scoring System. The rehabilitation and control groups differed in changes in FADI-S and Star Excursion Balance Test scores over time. Only the rehabilitation group improved in the FADI-S and in the posteromedial and anterior reaches of the Star Excursion Balance Test. Both groups demonstrated improvements in posterolateral reach; however, the rehabilitation group demonstrated greater improvement than the control group. When the groups were combined, participants reported improvements in FADI and FADI-S scores for the unstable ankle but not the stable ankle. Our data suggest training the stable ankle may result in improvements in balance and lower extremity function in the unstable ankle. This further supports the existence of a centrally mediated mechanism in the development of postural-control deficits after injury, as well as improved postural control after rehabilitation.

A comparison of freeze-drying and oven-drying preparation methods for bulk and compound-specific carbon stable isotope analyses: examples using the benthic macroinvertebrates Stenopsyche marmorata and Epeorus latifolium.

PubMed

Akamatsu, Fumikazu; Suzuki, Yaeko; Kato, Yoshikazu; Yoshimizu, Chikage; Tayasu, Ichiro

2016-01-15

Carbon stable isotope analysis of bulk samples and fatty acids is an established method for tracing carbon flow pathways and reconstructing trophic interactions, but there is no consensus on which sample drying method should be used for sample preparation. The aim of this study was to determine if freeze-drying and oven-drying treatments used to prepare samples of the benthic macroinvertebrates Stenopsyche marmorata and Epeorus latifolium for bulk and fatty-acid-specific carbon stable isotope analysis yield different isotopic ratio values. Five individuals each from two species were split in half; one half was freeze-dried and the other half was oven-dried. The samples were ground and the δ(13)C values of the bulk samples and eight fatty acids were measured following combustion using an isotope ratio mass spectrometer coupled to an elemental analyzer or gas chromatography system. The mean difference in the bulk and fatty acid δ(13)C values between freeze-dried and oven-dried samples was small (≤0.1‰ in both cases), although relatively large variations were observed in individual fatty-acid-specific δ(13)C values (maximum of ≤0.9 ‰). There were no significant differences in either bulk sample or fatty-acid-specific δ(13)C values between freeze-dried or oven-dried samples of the same species. Freeze-drying and oven-drying are equally acceptable methods for preparing freshly caught S. marmorata and E. latifolium samples for bulk and fatty-acid-specific carbon stable isotope analyses. Copyright © 2015 John Wiley & Sons, Ltd.

Biomechanical versus inertial information: stable individual differences in perception of self-rotation.

PubMed

Bruggeman, Hugo; Piuneu, Vadzim S; Rieser, John J; Pick, Herbert L

2009-10-01

When turning without vision or audition, people tend to perceive their locomotion as a change in heading relative to objects in the remembered surroundings. Such perception of self-rotation depends on sensitivity to information for movement from biomechanical activity of the locomotor system or from inertial activation of the vestibular and postural systems. The authors report 3 experiments that investigated the relative contributions of biomechanical and inertial information to perceiving the speed of self-rotation. Using a circular treadmill, the proportions of the 2 sources of proprioceptive information were varied, creating walking conditions with a constant rate of biomechanical activity but with variable speeds of rotation relative to inertial space. The results reveal stable individual differences in sensitivity to information for the perception of locomotion. Just more than half of the participants based their perceived speed of self-rotation on biomechanical information, whereas the others based theirs on inertial information. PsycINFO Database Record (c) 2009 APA, all rights reserved.

State and trait effects on individual differences in children's mathematical development.

PubMed

Bailey, Drew H; Watts, Tyler W; Littlefield, Andrew K; Geary, David C

2014-11-01

Substantial longitudinal relations between children's early mathematics achievement and their much later mathematics achievement are firmly established. These findings are seemingly at odds with studies showing that early educational interventions have diminishing effects on children's mathematics achievement across time. We hypothesized that individual differences in children's later mathematical knowledge are more an indicator of stable, underlying characteristics related to mathematics learning throughout development than of direct effects of early mathematical competency on later mathematical competency. We tested this hypothesis in two longitudinal data sets, by simultaneously modeling effects of latent traits (stable characteristics that influence learning across time) and states (e.g., prior knowledge) on children's mathematics achievement over time. Latent trait effects on children's mathematical development were substantially larger than state effects. Approximately 60% of the variance in trait mathematics achievement was accounted for by commonly used control variables, such as working memory, but residual trait effects remained larger than state effects. Implications for research and practice are discussed. © The Author(s) 2014.

Lipoprotein (a): impact by ethnicity and environmental and medical conditions

PubMed Central

Enkhmaa, Byambaa; Anuurad, Erdembileg; Berglund, Lars

2016-01-01

Levels of lipoprotein (a) [Lp(a)], a complex between an LDL-like lipid moiety containing one copy of apoB, and apo(a), a plasminogen-derived carbohydrate-rich hydrophilic protein, are primarily genetically regulated. Although stable intra-individually, Lp(a) levels have a skewed distribution inter-individually and are strongly impacted by a size polymorphism of the LPA gene, resulting in a variable number of kringle IV (KIV) units, a key motif of apo(a). The variation in KIV units is a strong predictor of plasma Lp(a) levels resulting in stable plasma levels across the lifespan. Studies have demonstrated pronounced differences across ethnicities with regard to Lp(a) levels and some of this difference, but not all of it, can be explained by genetic variations across ethnic groups. Increasing evidence suggests that age, sex, and hormonal impact may have a modest modulatory influence on Lp(a) levels. Among clinical conditions, Lp(a) levels are reported to be affected by kidney and liver diseases. PMID:26637279

State and Trait Effects on Individual Differences in Children's Mathematical Development

PubMed Central

Bailey, Drew H.; Watts, Tyler W.; Littlefield, Andrew K.; Geary, David C.

2015-01-01

Substantial longitudinal relations between children's early mathematics achievement and their much later mathematics achievement are firmly established. These findings are seemingly at odds with studies showing that early educational interventions have diminishing effects on children's mathematics achievement across time. We hypothesized that individual differences in children's later mathematical knowledge are more an indicator of stable, underlying characteristics related to mathematics learning throughout development than of direct effects of early mathematical competency on later mathematical competency. We tested this hypothesis in two longitudinal data sets, by simultaneously modeling effects of latent traits (stable characteristics that influence learning across time) and states (e.g., prior knowledge) on children's mathematics achievement over time. Latent trait effects on children's mathematical development were substantially larger than state effects. Approximately 60% of the variance in trait mathematics achievement was accounted for by commonly used control variables, such as working memory, but residual trait effects remained larger than state effects. Implications for research and practice are discussed. PMID:25231900

Gender differences in the relationship between marital status transitions and life satisfaction in later life.

PubMed

Chipperfield, J G; Havens, B

2001-05-01

This study examined life satisfaction among individuals who had undergone a transition in marital status and those whose marital status remained stable over a 7-year period. In particular, using data from a large-scale, longitudinal study we assessed life satisfaction as measured in 1983 and 1990 among 2,180 men and women between the ages of 67 and 102. Groups of individuals were identified on the basis of whether a spouse was present or absent at the two measurement points. This allowed for a classification of groups who experienced stability or transitions in marital status. Among those individuals whose marital status remained stable over the 7 years, women's life satisfaction declined and men's remained constant. Among those who experienced a transition--in particular, the loss of a spouse--a decline in life satisfaction was found for both men and women, decline being more predominant for men. In addition, men's life satisfaction increased over the 7-year period if they gained a spouse, whereas the same was not true for women. Generally, these findings imply that the relationship between marital status transitions or stability differs for men and women.

Stable isotope analysis of a pre-Hispanic Andean community: Reconstructing pre-Wari and Wari era diets in the hinterland of the Wari empire, Peru.

PubMed

Tung, Tiffiny A; Knudson, Kelly J

2018-01-01

Stable carbon and nitrogen isotope analysis is used to reconstruct diet among a pre-Hispanic population from the Peruvian Andes to evaluate whether local foodways changed with Wari imperial influence in the region. This study also compares local diet to other Wari-era sites. Samples derive from the site of Beringa in Peru and correspond primarily to pre-Wari (200-600 CE) and Wari (600-1,000 CE). We examine stable carbon isotopes from enamel (n = 29) and bone apatite (n = 22), and stable carbon and nitrogen isotopes from bone collagen (n = 29), and we present stable carbon and nitrogen isotope data on archaeological and modern fauna (n = 37) and plants (n = 19) from the region. There were no significant differences in either δ 13 C or δ 15 N from the pre-Wari to Wari era, indicating that those measurable aspects of diet did not change with Wari influence. There were no sex-based differences among juveniles (as inferred from δ 13 C from enamel carbonates) nor among adults (based on δ 13 C and δ 15 N from adult bone collagen). Comparisons to other Wari era sites show that Beringa individuals exhibited significantly lower δ 13 C values, suggesting that they consumed significantly less maize, a socially valued food. Further, the Froehle et al. (2012) stable isotope model suggests that the majority of the Beringa individuals consumed more C 3 than C 4 plants, and dietary protein was derived primarily from terrestrial animals and some marine resources. The similar diets from pre-Wari to Wari times hint at strong local dietary traditions and durable food trade networks during the period of Wari imperial influence. The presence of limited marine foods in the diet suggests a trade network with coastal groups or sojourns to the coast to gather marine resources. © 2017 Wiley Periodicals, Inc.

Reliabilities of mental rotation tasks: limits to the assessment of individual differences.

PubMed

Hirschfeld, Gerrit; Thielsch, Meinald T; Zernikow, Boris

2013-01-01

Mental rotation tasks with objects and body parts as targets are widely used in cognitive neuropsychology. Even though these tasks are well established to study between-groups differences, the reliability on an individual level is largely unknown. We present a systematic study on the internal consistency and test-retest reliability of individual differences in mental rotation tasks comparing different target types and orders of presentations. In total n = 99 participants (n = 63 for the retest) completed the mental rotation tasks with hands, feet, faces, and cars as targets. Different target types were presented in either randomly mixed blocks or blocks of homogeneous targets. Across all target types, the consistency (split-half reliability) and stability (test-retest reliabilities) were good or acceptable both for intercepts and slopes. At the level of individual targets, only intercepts showed acceptable reliabilities. Blocked presentations resulted in significantly faster and numerically more consistent and stable responses. Mental rotation tasks-especially in blocked variants-can be used to reliably assess individual differences in global processing speed. However, the assessment of the theoretically important slope parameter for individual targets requires further adaptations to mental rotation tests.

Terminal Decline in Well-Being: The Role of Multi-Indicator Constellations of Physical Health and Psychosocial Correlates

ERIC Educational Resources Information Center

Brandmaier, Andreas M.; Ram, Nilam; Wagner, Gert G.; Gerstorf, Denis

2017-01-01

Well-being is often relatively stable across adulthood and old age, but typically exhibits pronounced deteriorations and vast individual differences in the terminal phase of life. However, the factors contributing to these differences are not well understood. Using up to 25-year annual longitudinal data obtained from 4,404 now-deceased…

Testing the predictions of coping styles theory in threespined sticklebacks

PubMed Central

Bensky, Miles K.; Paitz, Ryan; Pereira, Laura; Bell, Alison M.

2017-01-01

Coping styles theory provides a framework for understanding individual variation in how animals respond to environmental change, and predicts how individual differences in stress responsiveness and behavior might relate to cognitive differences. According to coping styles theory, proactive individuals are bolder, less reactive to stressors, and more routinized than their reactive counterparts. A key tenet of coping styles theory is that variation in coping styles is maintained by tradeoffs with behavioral flexibility: proactive individuals excel in stable environments while more flexible, reactive individuals perform better in variable environments. Here, we assess evidence for coping styles within a natural population of threespined sticklebacks (Gasterosteus aculeatus). We developed a criterion-based learning paradigm to evaluate individual variation in initial and reversal learning. We observed strong individual differences in boldness, cortisol production, and learning performance. Consistent with coping styles, fish that released more cortisol were more timid in response to a predator attack and slower to learn a color discrimination task. However, there was no evidence that reactive individuals performed better when the environment changed (when the rewarded color was reversed). The failure to detect trade-offs between behavioral routinization and flexibility prompts other explanations for the maintenance of differing coping styles. PMID:28017848

The Origins of Individual Differences in How Learning Is Expressed in Rats: A General-Process Perspective

PubMed Central

2016-01-01

Laboratory rats can exhibit marked, qualitative individual differences in the form of acquired behaviors. For example, when exposed to a signal-reinforcer relationship some rats show marked and consistent changes in sign-tracking (interacting with the signal; e.g., a lever) and others show marked and consistent changes in goal-tracking (interacting with the location of the predicted reinforcer; e.g., the food well). Here, stable individual differences in rats’ sign-tracking and goal-tracking emerged over the course of training, but these differences did not generalize across different signal-reinforcer relationships (Experiment 1). This selectivity suggests that individual differences in sign- and goal-tracking reflect differences in the value placed on individual reinforcers. Two findings provide direct support for this interpretation: the palatability of a reinforcer (as measured by an analysis of lick-cluster size) was positively correlated with goal-tracking (and negatively correlated with sign-tracking); and sating rats with a reinforcer affected goal-tracking but not sign-tracking (Experiment 2). These results indicate that the observed individual differences in sign- and goal-tracking behavior arise from the interaction between the palatability or value of the reinforcer and processes of association as opposed to dispositional differences (e.g., in sensory processes, “temperament,” or response repertoire). PMID:27732045

Functional Brain Networks Are Dominated by Stable Group and Individual Factors, Not Cognitive or Daily Variation.

PubMed

Gratton, Caterina; Laumann, Timothy O; Nielsen, Ashley N; Greene, Deanna J; Gordon, Evan M; Gilmore, Adrian W; Nelson, Steven M; Coalson, Rebecca S; Snyder, Abraham Z; Schlaggar, Bradley L; Dosenbach, Nico U F; Petersen, Steven E

2018-04-18

The organization of human brain networks can be measured by capturing correlated brain activity with fMRI. There is considerable interest in understanding how brain networks vary across individuals or neuropsychiatric populations or are altered during the performance of specific behaviors. However, the plausibility and validity of such measurements is dependent on the extent to which functional networks are stable over time or are state dependent. We analyzed data from nine high-quality, highly sampled individuals to parse the magnitude and anatomical distribution of network variability across subjects, sessions, and tasks. Critically, we find that functional networks are dominated by common organizational principles and stable individual features, with substantially more modest contributions from task-state and day-to-day variability. Sources of variation were differentially distributed across the brain and differentially linked to intrinsic and task-evoked sources. We conclude that functional networks are suited to measuring stable individual characteristics, suggesting utility in personalized medicine. Copyright © 2018 Elsevier Inc. All rights reserved.

A dynamic game-theoretic model of parental care.

PubMed

Mcnamara, J M; Székely, T; Webb, J N; Houston, A I

2000-08-21

We present a model in which members of a mated pair decide whether to care for their offspring or desert them. There is a breeding season of finite length during which it is possible to produce and raise several batches of offspring. On deserting its offspring, an individual can search for a new mate. The probability of finding a mate depends on the number of individuals of each sex that are searching, which in turn depends upon the previous care and desertion decisions of all population members. We find the evolutionarily stable pattern of care over the breeding season. The feedback between behaviour and mating opportunity can result in a pattern of stable oscillations between different forms of care over the breeding season. Oscillations can also arise because the best thing for an individual to do at a particular time in the season depends on future behaviour of all population members. In the baseline model, a pair splits up after a breeding attempt, even if they both care for the offspring. In a version of the model in which a pair stays together if they both care, the feedback between behaviour and mating opportunity can lead to more than one evolutionarily stable form of care. Copyright 2000 Academic Press.

Longitudinal Effects on Early Adolescent Language: A Twin Study

ERIC Educational Resources Information Center

Harlarr, Nicole; De Thorne, Laura Segebart; Smith, Jamie Mahurin; Betancourt, Mariana Aparicio; Petrill, Stephen A.

2016-01-01

Purpose: We evaluated genetic and environmental contributions to individual differences in language skills during early adolescence, measured by both language sampling and standardized tests, and examined the extent to which these genetic and environmental effects are stable across time. Purpose: We evaluated genetic and environmental…

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

NASA Astrophysics Data System (ADS)

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 significantly between Hawaii and Maui adults, suggesting foraging segregation between these two populations. HAPE may be sensitive to changes in prey availability, given evidence of foraging specialization. However, conserving HAPE populations with apparently different foraging habits may be critical to preserve ecological diversity within the species.

Affect intensity and individual differences in informational style.

PubMed

Larsen, R J; Billings, D W; Cutler, S E

1996-03-01

Although individuals differ widely in the typical intensity of their affective experience, the mechanisms that create or maintain these differences are unclear. Larsen, Diener, and Cropanzano (1987) examined the hypothesis that individual differences in affect intensity (AI) are related to how people interpret emotional stimuli. They found that high AI individuals engaged in more personalizing and generalizing cognitions while construing emotional stimuli than low AI individuals. The present study extends these findings by examining cognitive activity during a different task-the generation of information to communicate about life events. Participants provided free-response descriptions of 16 life events. These descriptions were content coded for five informational style variables. It was found that the descriptive information generated by high AI participants contained significantly more references to emotional arousal, more focus on feelings, and more generalization compared to participants low in AI. These results are consistent with the notion that specific cognitive activity may lead to, or at least be associated with, dispositional affect intensity. In addition, the informational style variables identified in this study were stable over time and consistent across situations. Although men and women differ in AI, this difference becomes insignificant after controlling for informational style variation. Overall results are discussed in terms of a model of various psychological mechanisms that may potentially create or maintain individual differences in affect intensity.

Boldness predicts an individual's position along an exploration-exploitation foraging trade-off.

PubMed

Patrick, Samantha C; Pinaud, David; Weimerskirch, Henri

2017-09-01

Individuals do not have complete information about the environment and therefore they face a trade-off between gathering information (exploration) and gathering resources (exploitation). Studies have shown individual differences in components of this trade-off but how stable these strategies are in a population and the intrinsic drivers of these differences is not well understood. Top marine predators are expected to experience a particularly strong trade-off as many species have large foraging ranges and their prey often have a patchy distribution. This environment leads these species to exhibit pronounced exploration and exploitation phases but differences between individuals are poorly resolved. Personality differences are known to be important in foraging behaviour but also in the trade-off between exploration and exploitation. Here we test whether personality predicts an individual exploration-exploitation strategy using wide ranging wandering albatrosses (Diomedea exulans) as a model system. Using GPS tracking data from 276 wandering albatrosses, we extract foraging parameters indicative of exploration (searching) and exploitation (foraging) and show that foraging effort, time in patch and size of patch are strongly correlated, demonstrating these are indicative of an exploration-exploitation (EE) strategy. Furthermore, we show these are consistent within individuals and appear stable in the population, with no reproductive advantage. The searching and foraging behaviour of bolder birds placed them towards the exploration end of the trade-off, whereas shy birds showed greater exploitation. This result provides a mechanism through which individual foraging strategies may emerge. Age and sex affected components of the trade-off, but not the trade-off itself, suggesting these factors may drive behavioural compensation to maintain resource acquisition and this was supported by the evidence that there were no fitness consequence of any EE trait nor the trade-off itself. These results demonstrate a clear trade-off between information gathering and exploitation of prey patches, and reveals for the first time that boldness may drive these differences. This provides a mechanism through which widely reported links between personality and foraging may emerge. © 2017 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Stable Scalp EEG Spatiospectral Patterns Across Paradigms Estimated by Group ICA.

PubMed

Labounek, René; Bridwell, David A; Mareček, Radek; Lamoš, Martin; Mikl, Michal; Slavíček, Tomáš; Bednařík, Petr; Baštinec, Jaromír; Hluštík, Petr; Brázdil, Milan; Jan, Jiří

2018-01-01

Electroencephalography (EEG) oscillations reflect the superposition of different cortical sources with potentially different frequencies. Various blind source separation (BSS) approaches have been developed and implemented in order to decompose these oscillations, and a subset of approaches have been developed for decomposition of multi-subject data. Group independent component analysis (Group ICA) is one such approach, revealing spatiospectral maps at the group level with distinct frequency and spatial characteristics. The reproducibility of these distinct maps across subjects and paradigms is relatively unexplored domain, and the topic of the present study. To address this, we conducted separate group ICA decompositions of EEG spatiospectral patterns on data collected during three different paradigms or tasks (resting-state, semantic decision task and visual oddball task). K-means clustering analysis of back-reconstructed individual subject maps demonstrates that fourteen different independent spatiospectral maps are present across the different paradigms/tasks, i.e. they are generally stable.

Graph theoretic analysis of structural connectivity across the spectrum of Alzheimer's disease: The importance of graph creation methods

PubMed Central

Phillips, David J.; McGlaughlin, Alec; Ruth, David; Jager, Leah R.; Soldan, Anja

2015-01-01

Graph theory is increasingly being used to study brain connectivity across the spectrum of Alzheimer's disease (AD), but prior findings have been inconsistent, likely reflecting methodological differences. We systematically investigated how methods of graph creation (i.e., type of correlation matrix and edge weighting) affect structural network properties and group differences. We estimated the structural connectivity of brain networks based on correlation maps of cortical thickness obtained from MRI. Four groups were compared: 126 cognitively normal older adults, 103 individuals with Mild Cognitive Impairment (MCI) who retained MCI status for at least 3 years (stable MCI), 108 individuals with MCI who progressed to AD-dementia within 3 years (progressive MCI), and 105 individuals with AD-dementia. Small-world measures of connectivity (characteristic path length and clustering coefficient) differed across groups, consistent with prior studies. Groups were best discriminated by the Randić index, which measures the degree to which highly connected nodes connect to other highly connected nodes. The Randić index differentiated the stable and progressive MCI groups, suggesting that it might be useful for tracking and predicting the progression of AD. Notably, however, the magnitude and direction of group differences in all three measures were dependent on the method of graph creation, indicating that it is crucial to take into account how graphs are constructed when interpreting differences across diagnostic groups and studies. The algebraic connectivity measures showed few group differences, independent of the method of graph construction, suggesting that global connectivity as it relates to node degree is not altered in early AD. PMID:25984446

Origin and Manipulation of Stable Vortex Ground States in Permalloy Nanotubes.

PubMed

Zimmermann, Michael; Meier, Thomas Norbert Gerhard; Dirnberger, Florian; Kákay, Attila; Decker, Martin; Wintz, Sebastian; Finizio, Simone; Josten, Elisabeth; Raabe, Jörg; Kronseder, Matthias; Bougeard, Dominique; Lindner, Jürgen; Back, Christian Horst

2018-05-09

We present a detailed study on the static magnetic properties of individual permalloy nanotubes (NTs) with hexagonal cross-sections. Anisotropic magnetoresistance (AMR) measurements and scanning transmission X-ray microscopy (STXM) are used to investigate their magnetic ground states and its stability. We find that the magnetization in zero applied magnetic field is in a very stable vortex state. Its origin is attributed to a strong growth-induced anisotropy with easy axis perpendicular to the long axis of the tubes. AMR measurements of individual NTs in combination with micromagnetic simulations allow the determination of the magnitude of the growth-induced anisotropy for different types of NT coatings. We show that the strength of the anisotropy can be controlled by introducing a buffer layer underneath the magnetic layer. The magnetic ground states depend on the external magnetic field history and are directly imaged using STXM. Stable vortex domains can be introduced by external magnetic fields and can be erased by radio-frequency magnetic fields applied at the center of the tubes via a strip line antenna.

Social-class differences in self-concept clarity and their implications for well-being

PubMed Central

Na, Jinkyung; Chan, Micaela Y.; Lodi-Smith, Jennifer; Park, Denise C.

2017-01-01

A consistent/stable sense of the self is more valued in middle-class contexts than working-class contexts; hence we predicted that middle-class individuals would have higher SCC than working-class individuals. It is further expected that SCC would be more important to one’s well-being among middle-class individuals than among working-class individuals. Supporting these predictions, SCC was positively associated with higher social-class. Moreover, although SCC was associated with higher life satisfaction and better mental health, the association significantly attenuated among working-class individuals. In addition, SCC was not associated with physical health and its association with physical health did not interact with social class. PMID:27114215

Enjoyment and Anxiety in Second Language Communication: An Idiodynamic Approach

ERIC Educational Resources Information Center

Boudreau, Carmen; MacIntyre, Peter D.; Dewaele, Jean-Marc

2018-01-01

Emotions are a fleeting experience, sometimes lasting only moments before dissipating. Prior research in SLA has either ignored emotions, underestimated their relevance, or has studied them as a relatively stable individual difference variable. In contrast, the present study takes an idiodynamic approach to examine the rapidly changing…

Circadian Activity Rhythms, Time Urgency, and Achievement Concerns.

ERIC Educational Resources Information Center

Watts, Barbara L.

Many physiological and psychological processes fluctuate throughout the day in fairly stable, rhythmic patterns. The relationship between individual differences in circadian activity rhythms and a sense of time urgency were explored as well as a number of achievement-related variables. Undergraduates (N=308), whose circadian activity rhythms were…

A Genetic Analysis of Individual Differences in Dissociative Behaviors in Childhood and Adolescence

ERIC Educational Resources Information Center

Becker-Blease, Kathryn A.; Deater-Deckard, Kirby; Eley, Thalia; Freyd, Jennifer J.; Stevenson, Jim; Plomin, Robert

2004-01-01

Background: Dissociation--a pattern of general disruption in memory and consciousness--has been found to be an important cognitive component of children's and adults' coping with severe trauma. Dissociative experiences include amnesia, identity disturbance, age regression, difficulty with concentration, and trance states. Stable individual…

Short-Term and Long-Term Effects on Visual Word Recognition

ERIC Educational Resources Information Center

Protopapas, Athanassios; Kapnoula, Efthymia C.

2016-01-01

Effects of lexical and sublexical variables on visual word recognition are often treated as homogeneous across participants and stable over time. In this study, we examine the modulation of frequency, length, syllable and bigram frequency, orthographic neighborhood, and graphophonemic consistency effects by (a) individual differences, and (b) item…

Individual differences in GABA content are reliable but are not uniform across the human cortex

PubMed Central

Greenhouse, Ian; Noah, Sean; Maddock, Richard J; Ivry, Richard B

2016-01-01

1H magnetic resonance spectroscopy (MRS) provides a powerful tool to measure gamma-aminobutyric acid (GABA), the principle inhibitory neurotransmitter in the human brain. We asked whether individual differences in MRS estimates of GABA are uniform across the cortex or vary between regions. In two sessions, resting GABA concentrations in the lateral prefrontal, sensorimotor, dorsal premotor, and occipital cortices were measured in twenty-eight healthy individuals. GABA estimates within each region were stable across weeks, with low coefficients of variation. Despite this stability, the GABA estimates were not correlated between regions. In contrast, the percentage of brain tissue per volume, a control measure, was correlated between the three anterior regions. These results provide an interesting dissociation between an anatomical measure of individual differences and a neurochemical measure. The different patterns of anatomy and GABA concentrations have implications for understanding regional variation in the molecular topography of the brain in health and disease. PMID:27288552

Individual behavioral phenotypes: an integrative meta-theoretical framework. Why "behavioral syndromes" are not analogs of "personality".

PubMed

Uher, Jana

2011-09-01

Animal researchers are increasingly interested in individual differences in behavior. Their interpretation as meaningful differences in behavioral strategies stable over time and across contexts, adaptive, heritable, and acted upon by natural selection has triggered new theoretical developments. However, the analytical approaches used to explore behavioral data still address population-level phenomena, and statistical methods suitable to analyze individual behavior are rarely applied. I discuss fundamental investigative principles and analytical approaches to explore whether, in what ways, and under which conditions individual behavioral differences are actually meaningful. I elaborate the meta-theoretical ideas underlying common theoretical concepts and integrate them into an overarching meta-theoretical and methodological framework. This unravels commonalities and differences, and shows that assumptions of analogy to concepts of human personality are not always warranted and that some theoretical developments may be based on methodological artifacts. Yet, my results also highlight possible directions for new theoretical developments in animal behavior research. Copyright © 2011 Wiley Periodicals, Inc.

Neurocognitive function in clinically stable individuals with long-term bipolar I disorder: Comparisons with schizophrenia patients and controls.

PubMed

Lin, Pei-Yun; Wang, Peng-Wei; Chen, Cheng-Sheng; Yen, Cheng-Fang

2017-05-01

This study compared the levels of the five domains of neurocognitive function-executive function, attention, memory, verbal comprehension, and perceptual organization-among clinically stable individuals with long-term bipolar I disorder, individuals with long-term schizophrenia, and a group of controls. We recruited a total of 93 clinically stable individuals with bipolar I disorder, 94 individuals with schizophrenia, and 106 controls in this study. Their neurocognitive function was measured using a series of neurocognitive function tests: the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III), Line Cancellation Test, Visual Form Discrimination, Controlled Oral Word Association Test, Wisconsin Card Sorting Test, Continuous Performance Task, and Wechsler Memory Scale-Third Edition. Neurocognitive function was compared among the three groups through a multivariate analysis of variance. The results indicated that when the effect of age was controlled, clinically stable individuals with bipolar I disorder and those with schizophrenia demonstrated poor neurocognitive function on all tests except for the WAIS-III Similarity and Information and the Line Cancellation Test. The individuals with bipolar I disorder had similar levels of neurocognitive function compared with the schizophrenia group, but higher levels of neurocognitive function on the WAIS-III Comprehension, Controlled Oral Word Association Test, and Wechsler Memory Scale-Third Edition Auditory Immediate and Delayed Index and Visual Immediate and Delayed Index. The conclusions of this study suggest that compared with controls, individuals with long-term bipolar I disorder and those with long-term schizophrenia have poorer neurocognitive function, even when clinically stable. Individuals with long-term bipolar I disorder and those with long-term schizophrenia have similar levels of deficits in several domains of neurocognitive function. Copyright © 2017. Published by Elsevier Taiwan.

Stable isotope ratio analysis for authentication of lamb meat.

PubMed

Piasentier, E; Valusso, R; Camin, F; Versini, G

2003-07-01

The effectiveness of the analysis of stable isotope ratios ((13)C/(12)C and (15)N/(14)N) in fractions of lamb meat, measured by isotope ratio mass spectrometry, was evaluated as a method of feeding and geographical origin authentication. Analyses were carried out on meat from 12 lamb types, produced in couples in six European countries (country of origin, CO) and divided in three groups according to the feeding regime during their finishing period: suckled milk only, pasture without any solid supplementation and supplementation containing maize grain (feeding regime, FR). These analyses were made on two samples of longissimus thoracis muscle, taken from the 13th rib section of the left side of two different lambs, randomly chosen between the 120 selected to represent each lamb type. δ(13)C values varied significantly in different meat fractions, the difference being higher in protein than in fat (average difference 5.0‰). However, the pairs δ(13)C values of crude fat and protein were highly correlated (r=0.976) and affected by lamb type in a similar fashion, mainly reflecting animals' feeding regime. Even δ(15)N values of meat protein fraction showed significant differences between lamb types, not dependant on the feeding regime. In fact, lambs fed on similar diets, but in different countries, gave meat with different (15)N relative abundances. These findings provide the possibility of discriminating lamb types within the same feeding regime. Canonical discriminant analysis was carried out to evaluate whether lamb meat from different CO or FR or CO×FR interaction could be mathematically distinguished by its stable isotope ratios. On the basis of CO, the corrected empirical allocation of 79.2% of the initial observations and the corrected cross-validation of two thirds of the individual meat samples was obtained. FR gave better results: 91.7% of the individual meat samples was both correctly allocated and cross-validated, indicating the high potential of stable isotope ratio analysis as a tool for lamb diet characterisation. The most satisfactory classification attained, using K-means clustering technique and canonical discriminant analysis, enabled a good resolution of six CO×FR groups of lamb types: Icelandic fed on pasture; British and French grazing; Italian; suckled and Karagouniko concentrates finished; French Lacaune; Ternasco de Aragon. It was concluded that multielement stable isotope analysis may be considered promising for the reliable evaluation of lamb meat authenticity, in the same way as for wine, fruit juice, honey and dairy products.

Expertise Effects in Face-Selective Areas are Robust to Clutter and Diverted Attention, but not to Competition

PubMed Central

McGugin, Rankin Williams; Van Gulick, Ana E.; Tamber-Rosenau, Benjamin J.; Ross, David A.; Gauthier, Isabel

2015-01-01

Expertise effects for nonface objects in face-selective brain areas may reflect stable aspects of neuronal selectivity that determine how observers perceive objects. However, bottom-up (e.g., clutter from irrelevant objects) and top-down manipulations (e.g., attentional selection) can influence activity, affecting the link between category selectivity and individual performance. We test the prediction that individual differences expressed as neural expertise effects for cars in face-selective areas are sufficiently stable to survive clutter and manipulations of attention. Additionally, behavioral work and work using event related potentials suggest that expertise effects may not survive competition; we investigate this using functional magnetic resonance imaging. Subjects varying in expertise with cars made 1-back decisions about cars, faces, and objects in displays containing one or 2 objects, with only one category attended. Univariate analyses suggest car expertise effects are robust to clutter, dampened by reducing attention to cars, but nonetheless more robust to manipulations of attention than competition. While univariate expertise effects are severely abolished by competition between cars and faces, multivariate analyses reveal new information related to car expertise. These results demonstrate that signals in face-selective areas predict expertise effects for nonface objects in a variety of conditions, although individual differences may be expressed in different dependent measures depending on task and instructions. PMID:24682187

Does the early social environment prepare individuals for the future? A match-mismatch experiment in female wild cavies.

PubMed

Sangenstedt, Susanne; Szardenings, Carsten; Sachser, Norbert; Kaiser, Sylvia

2018-01-01

The social environment that mothers experience during pregnancy and lactation has a strong effect on the developing offspring. Whether offspring can be adaptively shaped to match an environment that is similar to the maternal one is still a major question in research. Our previous work in wild cavies showed that females whose mothers lived in a stable social environment with few social challenges during pregnancy and lactation (SE-daughters) developed different behavioral phenotypes than females whose mothers lived in an unstable social environment with frequent social challenges during pregnancy and lactation (UE-daughters). In the present study we investigated whether SE-daughters are better adapted to a stable social environment, similar to their maternal one, than are UE-daughters, for which the stable social environment represents a mismatch with their maternal one. For this purpose, we established pairs of one UE- and one SE-daughter and housed them together under stable social conditions for one week. Dominance ranks, behavioral profiles, glucocorticoid levels, cortisol responsiveness and body weight changes were compared between the groups. We hypothesized that SE-daughters fare better in a stable social setting compared to UE-daughters. After one week of cohabitation in the stable social condition, UE-daughters had higher glucocorticoid levels, tended to gain less body weight within the first three days and displayed higher frequencies of energy-demanding behaviors such as rearing and digging than SE-daughters. However, there was no difference in cortisol responsiveness as well as in dominance ranks between UE- and SE-daughters. Higher glucocorticoid levels and less body weight gain imply that UE-daughters had higher energy demands than SE-daughters. This high energy demand of UE-daughters is further indicated by the increased display of rearing and digging behavior. Rearing implies increased vigilance, which is far too energy demanding in a stable social condition but may confer an advantage in an unstable social environment. Hence, SE-daughters seem to better match a stable social environment, similar to their maternal one, than do UE-daughters, who encountered a mismatch to their maternal environment. This data supports the environmental matching hypothesis, stating that individuals manage the best in environments that correspond to their maternal ones.

Preschool Drawing and School Mathematics: The Nature of the Association.

PubMed

Malanchini, Margherita; Tosto, Maria G; Garfield, Victoria; Dirik, Aysegul; Czerwik, Adrian; Arden, Rosalind; Malykh, Sergey; Kovas, Yulia

2016-05-01

The study examined the etiology of individual differences in early drawing and of its longitudinal association with school mathematics. Participants (N = 14,760), members of the Twins Early Development Study, were assessed on their ability to draw a human figure, including number of features, symmetry, and proportionality. Human figure drawing was moderately stable across 6 months (average r = .40). Individual differences in drawing at age 4½ were influenced by genetic (.21), shared environmental (.30), and nonshared environmental (.49) factors. Drawing was related to later (age 12) mathematical ability (average r = .24). This association was explained by genetic and shared environmental factors that also influenced general intelligence. Some genetic factors, unrelated to intelligence, also contributed to individual differences in drawing. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

Long-Term Species, Sexual and Individual Variations in Foraging Strategies of Fur Seals Revealed by Stable Isotopes in Whiskers

PubMed Central

Kernaléguen, Laëtitia; Cazelles, Bernard; Arnould, John P. Y.; Richard, Pierre; Guinet, Christophe; Cherel, Yves

2012-01-01

Background Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals. Methodology/Principal Findings The foraging strategies of sympatric fur seals (Arctocephalus gazella and A. tropicalis) were examined using the stable isotope signature of serially sampled whiskers. Most whiskers exhibited synchronous δ13C and δ15N oscillations that correspond to the seal annual movements over the long term (up to 8 years). δ13C and δ15N values were spread over large ranges, with differences between species, sexes and individuals. The main segregating mechanism operates at the spatial scale. Most seals favored foraging in subantarctic waters (where the Crozet Islands are located) where they fed on myctophids. However, A. gazella dispersed in the Antarctic Zone and A. tropicalis more in the subtropics. Gender differences in annual time budget shape the seal movements. Males that do not perform any parental care exhibited large isotopic oscillations reflecting broad annual migrations, while isotopic values of females confined to a limited foraging range during lactation exhibited smaller changes. Limited inter-individual isotopic variations occurred in female seals and in male A. tropicalis. In contrast, male A. gazella showed large inter-individual variations, with some males migrating repeatedly to high-Antarctic waters where they fed on krill, thus meaning that individual specialization occurred over years. Conclusions/Significance Whisker isotopic signature yields unique long-term information on individual behaviour that integrates the spatial, trophic and temporal dimensions of the ecological niche. The method allows depicting the entire realized niche of the species, including some of its less well-known components such as age-, sex-, individual- and migration-related changes. It highlights intrapopulation heterogeneity in foraging strategies that could have important implications for likely demographic responses to environmental variability. PMID:22431988

Emerging Hyperprolactinemic Galactorrhea in Obsessive Compulsive Disorder with a Stable Dose of Fluoxetine.

PubMed

Chatterjee, Seshadri Sekhar; Mitra, Sayantanava; Mallik, Nitu

2015-12-31

While fluoxetine (FXT) is a frequently prescribed selective serotonin reuptake inhibitor (SSRI), with few major side-effects; altered serotonergic transmissions in hypothalamic pathways might lead to a distressing, and often embarrassing, manifestation of galactorrhea by altering prolactin release in those on FXT. We report here a case of FXT-induced hyperprolactinemic galactorrhea developing late into treatment on a stable regimen, who responded well to subsequent replacement with sertraline. Based on present finding, we suggest that while SSRIs may share similar mechanisms of action, there exist individual differences in their effects on prolactin secretion pathways.

Why do the lonely stay lonely? Chronically lonely adolescents' attributions and emotions in situations of social inclusion and exclusion.

PubMed

Vanhalst, Janne; Soenens, Bart; Luyckx, Koen; Van Petegem, Stijn; Weeks, Molly S; Asher, Steven R

2015-11-01

The goal of this study was to identify mechanisms associated with chronic loneliness by examining the effect of adolescents' accumulated history of loneliness on responses to new social situations. Specifically, this study investigated whether attributions and emotions in situations of social inclusion and exclusion differ between chronically lonely adolescents and adolescents with a different loneliness history. A total of 730 adolescents (Mage at Wave 1 = 15.43 years) participated in a 4-wave longitudinal study with annual loneliness assessments. A chronic loneliness trajectory was identified, in addition to low-stable, moderate-stable, moderate-increasing, and high-decreasing loneliness trajectories. At Wave 4, vignettes depicting social inclusion and exclusion were presented, and participants rated a set of attributions and emotions following each vignette. Compared with individuals following other trajectories, chronically lonely adolescents were characterized by hypersensitivity to social exclusion (i.e., higher levels of negative emotions) and hyposensitivity to social inclusion (i.e., lower levels of enthusiasm). Further, chronically lonely adolescents had a stronger tendency to attribute social inclusion to circumstantial factors and social exclusion to internal and stable characteristics. This maladaptive attribution style partially mediated their emotional experiences. Together, results indicate that chronically lonely individuals respond to social situations in ways that may perpetuate rather than reduce their loneliness. (c) 2015 APA, all rights reserved).

Does Group Size Matter for Behavior in Online Trust Dilemmas?

PubMed

Artinger, Sabrina; Vulkan, Nir

2016-01-01

How does group size influence behavior in online trust dilemmas? We investigate cooperation in groups of 4 to 100 players. While overall levels of cooperation are stable across group sizes, we find significant gender differences: women increase cooperation with group size and cooperate significantly more than men in large groups. These results are robust when controlling for risk aversion, age, and other individual differences. They highlight the importance of studying behavior and gender differences in large groups.

Individual Variation in Contagious Yawning Susceptibility Is Highly Stable and Largely Unexplained by Empathy or Other Known Factors

PubMed Central

Bartholomew, Alex J.; Cirulli, Elizabeth T.

2014-01-01

The contagious aspect of yawning is a well-known phenomenon that exhibits variation in the human population. Despite the observed variation, few studies have addressed its intra-individual reliability or the factors modulating differences in the susceptibility of healthy volunteers. Due to its obvious biological basis and impairment in diseases like autism and schizophrenia, a better understanding of this trait could lead to novel insights into these conditions and the general biological functioning of humans. We administered 328 participants a 3-minute yawning video stimulus, a cognitive battery, and a comprehensive questionnaire that included measures of empathy, emotional contagion, circadian energy rhythms, and sleepiness. Individual contagious yawning measurements were found to be highly stable across testing sessions, both in a lab setting and if administered remotely online, confirming that certain healthy individuals are less susceptible to contagious yawns than are others. Additionally, most individuals who failed to contagiously yawn in our study were not simply suppressing their reaction, as they reported not even feeling like yawning in response to the stimulus. In contrast to previous studies indicating that empathy, time of day, or intelligence may influence contagious yawning susceptibility, we found no influence of these variables once accounting for the age of the participant. Participants were less likely to show contagious yawning as their age increased, even when restricting to ages of less than 40 years. However, age was only able to explain 8% of the variability in the contagious yawn response. The vast majority of the variability in this extremely stable trait remained unexplained, suggesting that studies of its inheritance are warranted. PMID:24632594

Curriculum Designed for an Equitable Pedagogy

ERIC Educational Resources Information Center

Cullen, Roxanne; Hill, Reinhold R.

2013-01-01

Rather than viewing curriculum as linear, a post-modern, learner-centered curriculum design is a spiral or recursive curriculum. Post-modernism provides a much less stable foundation upon which to build a model of student learning, a model that recognizes and even celebrates individual difference and one that is supported by research on how people…

Motivational Dynamics in Language Learning: Change, Stability, and Context

ERIC Educational Resources Information Center

Waninge, Freerkien; Dörnyei, Zoltán; De Bot, Kees

2014-01-01

Motivation as a variable in L2 development is no longer seen as the stable individual difference factor it was once believed to be: Influenced by process-oriented models and principles, and especially by the growing understanding of how complex dynamic systems work, researchers have been focusing increasingly on the dynamic and changeable nature…

Cultural Differences in the Self Esteem and Adaptation of Spanish-Speaking Second Generation Adolescents.

ERIC Educational Resources Information Center

Portes, Pedro R.; Zady, Madelon F.

Development of self-esteem tends to become stable in middle adolescence for mainstream groups, but relatively little is known about self-esteem development of individuals in groups undergoing cultural adaptation, such as Spanish-speaking adolescents. The idea that immigrant students (voluntary minorities) are alike in many psychological and social…

The Development of a Scale To Measure Negative Affectivity.

ERIC Educational Resources Information Center

Stokes, Joseph; Levin, Ira

Negative affectivity (NA) has been defined as a stable and pervasive individual difference characterized by a disposition to experience aversive emotional states (D. Watson and L. A. Clark, 1984). A brief self-report scale was developed to assess NA. The initial 28-item scale (which included seven items each representing nervousness/calmness,…

Temperament and Development: The Role of Context in a Biologically Based System

ERIC Educational Resources Information Center

Wachs, Theodore D.

2004-01-01

One way to connect research with its clinical application is to examine the interplay between context and child. This article discusses the relationship between temperamental characteristics and the caregiving environment. During the first year of life, individual temperament differences in newborns are moderately stable and influence the nature…

Biomechanical versus Inertial Information: Stable Individual Differences in Perception of Self-Rotation

ERIC Educational Resources Information Center

Bruggeman, Hugo; Piuneu, Vadzim S.; Rieser, John J.; Pick, Herbert L., Jr.

2009-01-01

When turning without vision or audition, people tend to perceive their locomotion as a change in heading relative to objects in the remembered surroundings. Such perception of self-rotation depends on sensitivity to information for movement from biomechanical activity of the locomotor system or from inertial activation of the vestibular and…

Working Memory Is Related to Perceptual Processing: A Case from Color Perception

ERIC Educational Resources Information Center

Allen, Elizabeth C.; Beilock, Sian L.; Shevell, Steven K.

2011-01-01

We explored the relation between individual differences in working memory (WM) and color constancy, the phenomenon of color perception that allows us to perceive the color of an object as relatively stable under changes in illumination. Successive color constancy (measured by first viewing a colored surface under a particular illumination and…

Developmental Changes in the Coherence of Essentialist Beliefs about Psychological Characteristics

ERIC Educational Resources Information Center

Gelman, Susan A.; Heyman, Gail D.; Legare, Cristine H.

2007-01-01

Essentialism is the belief that certain characteristics (of individuals or categories) may be relatively stable, unchanging, likely to be present at birth, and biologically based. The current studies examined how different essentialist beliefs interrelate. For example, does thinking that a property is innate imply that the property cannot be…

Defensive aggregation (huddling) in Rattus norvegicus toward predator odor: individual differences, social buffering effects and neural correlates.

PubMed

Bowen, Michael T; Kevin, Richard C; May, Matthew; Staples, Lauren G; Hunt, Glenn E; McGregor, Iain S

2013-01-01

Aggregation is a defensive strategy employed by many prey species in response to predatory threat. Our group has characterized defensive aggregation (huddling) in Rattus norvegicus in response to a ball of cat fur. In this situation some rats huddle less, and approach the threatening cue more than others (active vs. passive responders). The present study explored whether active responding is a stable phenotype associated with behaviors outside direct predatory encounters. The neural substrates of active and passive responding under predatory threat were explored using c-Fos immunohistochemistry. Finally, we examined whether the presence of conspecifics during predatory threat biases behavior towards active responding. Active and passive responding styles were found to be stable in individual rats across consecutive group exposures to cat fur, and were predicted by anxiety-like behavior in an open-field emergence test. Active responders displayed less conditioned fear in an environment associated with predatory threat, and had higher post-exposure intake of a weak sucrose solution (a test of "anhedonia"). Active responding was associated with: greater cat fur-induced activation of the accessory olfactory bulb, reflecting greater olfactory stimulation in rats actively approaching the fur; lowered activation of somatosensory cortex, reflecting reduced huddling with conspecifics; and reduced activation in the lateral septum. Social exposure to cat fur promoted active responding relative to individual exposure, and lowered c-Fos expression in the dorsomedial periaqueductal grey, medial caudate putamen and lateral habenula. We conclude that individual differences in anti-predator behavior appear stable traits with active responders having a more resilient phenotype. Social exposure to predatory threat has an acute buffering effect, subtly changing the neural and behavioral response towards threat and encouraging active responding. An association between active responding and lower c-Fos expression in the lateral septum is consistent with previous studies that highlight this region as an important neurobiological substrate of defensive aggregation.

Defensive Aggregation (Huddling) in Rattus Norvegicus toward Predator Odor: Individual Differences, Social Buffering Effects and Neural Correlates

PubMed Central

Bowen, Michael T.; Kevin, Richard C.; May, Matthew; Staples, Lauren G.; Hunt, Glenn E.; McGregor, Iain S.

2013-01-01

Aggregation is a defensive strategy employed by many prey species in response to predatory threat. Our group has characterized defensive aggregation (huddling) in Rattus norvegicus in response to a ball of cat fur. In this situation some rats huddle less, and approach the threatening cue more than others (active vs. passive responders). The present study explored whether active responding is a stable phenotype associated with behaviors outside direct predatory encounters. The neural substrates of active and passive responding under predatory threat were explored using c-Fos immunohistochemistry. Finally, we examined whether the presence of conspecifics during predatory threat biases behavior towards active responding. Active and passive responding styles were found to be stable in individual rats across consecutive group exposures to cat fur, and were predicted by anxiety-like behavior in an open-field emergence test. Active responders displayed less conditioned fear in an environment associated with predatory threat, and had higher post-exposure intake of a weak sucrose solution (a test of “anhedonia”). Active responding was associated with: greater cat fur-induced activation of the accessory olfactory bulb, reflecting greater olfactory stimulation in rats actively approaching the fur; lowered activation of somatosensory cortex, reflecting reduced huddling with conspecifics; and reduced activation in the lateral septum. Social exposure to cat fur promoted active responding relative to individual exposure, and lowered c-Fos expression in the dorsomedial periaqueductal grey, medial caudate putamen and lateral habenula. We conclude that individual differences in anti-predator behavior appear stable traits with active responders having a more resilient phenotype. Social exposure to predatory threat has an acute buffering effect, subtly changing the neural and behavioral response towards threat and encouraging active responding. An association between active responding and lower c-Fos expression in the lateral septum is consistent with previous studies that highlight this region as an important neurobiological substrate of defensive aggregation. PMID:23922655

Three, six, or twelve months of dual antiplatelet therapy after DES implantation in patients with or without acute coronary syndromes: an individual patient data pairwise and network meta-analysis of six randomized trials and 11 473 patients.

PubMed

Palmerini, Tullio; Della Riva, Diego; Benedetto, Umberto; Bacchi Reggiani, Letizia; Feres, Fausto; Abizaid, Alexandre; Gilard, Martine; Morice, Marie-Claude; Valgimigli, Marco; Hong, Myeong-Ki; Kim, Byeong-Keuk; Jang, Yangsoo; Kim, Hyo-Soo; Park, Kyung Woo; Colombo, Antonio; Chieffo, Alaide; Sangiorgi, Diego; Biondi-Zoccai, Giuseppe; Généreux, Philippe; Angelini, Gianni D; Pufulete, Maria; White, Jonathon; Bhatt, Deepak L; Stone, Gregg W

2017-04-07

We sought to determine whether the optimal dual antiplatelet therapy (DAPT) duration after drug-eluting stent (DES) placement varies according to clinical presentation. We performed an individual patient data pairwise and network meta-analysis comparing short-term (≤6-months) versus long-term (1-year) DAPT as well as 3-month vs. 6-month vs 1-year DAPT. The primary study outcome was the 1-year composite risk of myocardial infarction (MI) or definite/probable stent thrombosis (ST). Six trials were included in which DAPT after DES consisted of aspirin and clopidogrel. Among 11 473 randomized patients 6714 (58.5%) had stable CAD and 4758 (41.5%) presented with acute coronary syndrome (ACS), the majority of whom (67.0%) had unstable angina. In ACS patients, ≤6-month DAPT was associated with non-significantly higher 1-year rates of MI or ST compared with 1-year DAPT (Hazard Ratio (HR) 1.48, 95% Confidence interval (CI) 0.98-2.22; P = 0.059), whereas in stable patients rates of MI and ST were similar between the two DAPT strategies (HR 0.93, 95%CI 0.65-1.35; P = 0.71; Pinteraction = 0.09). By network meta-analysis, 3-month DAPT, but not 6-month DAPT, was associated with higher rates of MI or ST in ACS, whereas no significant differences were apparent in stable patients. Short DAPT was associated with lower rates of major bleeding compared with 1-year DAPT, irrespective of clinical presentation. All-cause mortality was not significantly different with short vs. long DAPT in both patients with stable CAD and ACS. Optimal DAPT duration after DES differs according to clinical presentation. In the present meta-analysis, despite the fact that most enrolled ACS patients were relatively low risk, 3-month DAPT was associated with increased ischaemic risk, whereas 3-month DAPT appeared safe in stable CAD. Prolonged DAPT increases bleeding regardless of clinical presentation. Further study is required to identify the optimal duration of DAPT after DES in individual patients based on their relative ischaemic and bleeding risks. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Social-class differences in self-concept clarity and their implications for well-being.

PubMed

Na, Jinkyung; Chan, Micaela Y; Lodi-Smith, Jennifer; Park, Denise C

2018-06-01

A consistent/stable sense of the self is more valued in middle-class contexts than working-class contexts; hence, we predicted that middle-class individuals would have higher self-concept clarity than working-class individuals. It is further expected that self-concept clarity would be more important to one's well-being among middle-class individuals than among working-class individuals. Supporting these predictions, self-concept clarity was positively associated with higher social class. Moreover, although self-concept clarity was associated with higher life satisfaction and better mental health, the association significantly attenuated among working-class individuals. In addition, self-concept clarity was not associated with physical health and its association with physical health did not interact with social class.

The Cultural Boundaries of Perspective-Taking: When and Why Perspective-Taking Reduces Stereotyping.

PubMed

Wang, Cynthia S; Lee, Margaret; Ku, Gillian; Leung, Angela K-Y

2018-06-01

Research conducted in Western cultures indicates that perspective-taking is an effective social strategy for reducing stereotyping. The current article explores whether and why the effects of perspective-taking on stereotyping differ across cultures. Studies 1 and 2 established that perspective-taking reduces stereotyping in Western but not in East Asian cultures. Using a socioecological framework, Studies 2 and 3 found that relational mobility, that is, the extent to which individuals' social environments provide them opportunities to choose new relationships and terminate old ones, explained our effect: Perspective-taking was negatively associated with stereotyping in relationally mobile (Western) but not in relationally stable (East Asian) environments. Finally, Study 4 examined the proximal psychological mechanism underlying the socioecological effect: Individuals in relationally mobile environments are more motivated to develop new relationships than those in relationally stable environments. Subsequently, when this motivation is high, perspective-taking increases self-target group overlap, which then decreases stereotyping.

State-trait decomposition of Name Letter Test scores and relationships with global self-esteem.

PubMed

Perinelli, Enrico; Alessandri, Guido; Donnellan, M Brent; Łaguna, Mariola

2018-06-01

The Name Letter Test (NLT) assesses the degree that participants show a preference for an individual's own initials. The NLT was often thought to measure implicit self-esteem, but recent literature reviews do not equivocally support this hypothesis. Several authors have argued that the NLT is most strongly associated with the state component of self-esteem. The current research uses a modified STARTS model to (a) estimate the percentage of stable and transient components of the NLT and (b) estimate the covariances between stable/transient components of the NLT and stable/transient components of self-esteem and positive and negative affect. Two longitudinal studies were conducted with different time lags: In Study 1, participants were assessed daily for 7 consecutive days, whereas in Study 2, participants were assessed weekly for 8 consecutive weeks. Participants also completed a battery of questionnaires including global self-esteem, positive affect, and negative affect. In both studies, the NLT showed (a) high stability across time, (b) a high percentage of stable variance, (c) no significant covariance with stable and transient factors for global self-esteem, and (d) a different pattern of correlations with stable and transient factors of affect than global self-esteem. Collectively, these results further undermine the claim that the NLT is a valid measure of implicit self-esteem. Future work is needed to identify theoretically grounded correlates of the NLT. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Bilateral Improvements in Lower Extremity Function After Unilateral Balance Training in Individuals With Chronic Ankle Instability

PubMed Central

Hale, Sheri A.; Fergus, Andrea; Axmacher, Rachel; Kiser, Kimberly

2014-01-01

Context: Bilateral improvements in postural control have been reported among individuals with acute lateral ankle sprains and individuals with chronic ankle instability (CAI) when only the unstable ankle is rehabilitated. We do not know if training the stable ankle will improve function on the unstable side. Objective: To explore the effects of a unilateral balance-training program on bilateral lower extremity balance and function in individuals with CAI when only the stable limb is trained. Design: Cohort study. Setting: University clinical research laboratory. Patients or Other Participants: A total of 34 volunteers (8 men, 26 women; age = 24.32 ± 4.95 years, height = 167.01 ± 9.45 cm, mass = 77.54 ± 23.76 kg) with CAI were assigned to the rehabilitation (n = 17) or control (n = 17) group. Of those, 27 (13 rehabilitation group, 14 control group) completed the study. Intervention(s): Balance training twice weekly for 4 weeks. Main Outcome Measure(s): Foot and Ankle Disability Index (FADI), FADI Sport (FADI-S), Star Excursion Balance Test, and Balance Error Scoring System. Results: The rehabilitation and control groups differed in changes in FADI-S and Star Excursion Balance Test scores over time. Only the rehabilitation group improved in the FADI-S and in the posteromedial and anterior reaches of the Star Excursion Balance Test. Both groups demonstrated improvements in posterolateral reach; however, the rehabilitation group demonstrated greater improvement than the control group. When the groups were combined, participants reported improvements in FADI and FADI-S scores for the unstable ankle but not the stable ankle. Conclusions: Our data suggest training the stable ankle may result in improvements in balance and lower extremity function in the unstable ankle. This further supports the existence of a centrally mediated mechanism in the development of postural-control deficits after injury, as well as improved postural control after rehabilitation. PMID:24568231

Patterns of mortality among South Florida Manatees: Evidence from oxygen, sulfur and deuterium stable isotopes

NASA Astrophysics Data System (ADS)

MacAvoy, S. E.; Bacalan, V.; Kazantseva, M.; Rhodes, J.; Kim, K.

2012-12-01

The Florida manatee (Trichechus manatus latirostris) is an endangered marine mammal whose coastal habitat has been heavily altered by human development. Sources of mortality include anthropogenic and environmental causes. Necropsies were completed on 75 deceased individuals, and tissues, including bone samples, were collected for later analysis. This study investigates the utility of manatee bone stable oxygen (δ18O), sulfur (δ34S) and deuterium (δD) for determining where the animals lived (which may not be where they where their bodies were recovered), and the relative importance of marine versus freshwater for the individual animals. The isotopes can provide a "geochemical map" showing the distribution of mortality, aiding in the evaluation of geographical patterns in mortality. The δ18O signatures of the bones ranged from 14 to 18.5‰, with no significant difference between male and female mean values. δ18O significantly decreased with increasing latitude (p=.0016), a trend positively correlated with coastal Florida seawater δ18O literature values obtained from the NASA Global Seawater Oxygen-18 Database (http://data.giss.nasa.gov/o18data/) and the EAIA stable isotope database (http://www.univie.ac.at/cartography/project/wiser/). Bone δ34S indicated the influence of marine versus coastal freshwater dietary sources on the animals. Most individuals showed 34S-depleted signatures, which indicated a non-marine sulfur source; however some individuals clearly had taken up marine sulfate (mean 4.9 ± 3.7‰, range 0.8 to 13.8‰). Deuterium values were not available at the time this abstract was written, however we hypothesize that those values will co-vary with δ18O. We conclude that manatee diets are based on both marine and freshwater sources, but freshwater sources exert more influence. Marine water and manatee δ18O co-vary with latitude, suggesting that stable oxygen isotopes may be useful indicators of the latitude where manatees lived.

Working memory is related to perceptual processing: a case from color perception.

PubMed

Allen, Elizabeth C; Beilock, Sian L; Shevell, Steven K

2011-07-01

We explored the relation between individual differences in working memory (WM) and color constancy, the phenomenon of color perception that allows us to perceive the color of an object as relatively stable under changes in illumination. Successive color constancy (measured by first viewing a colored surface under a particular illumination and later recalling it under a new illumination) was better for higher WM individuals than for lower WM individuals. Moreover, the magnitude of this WM difference depended on how much contextual information was available in the scene, which typically improves color constancy. By contrast, simple color memory, measured by viewing and recalling a colored surface under the same illumination, showed no significant relation to WM. This study reveals a relation between WM and a low-level perceptual process not previously thought to operate within the confines of attentional control, and it provides a first account of the individual differences in color constancy known about for decades.

Working memory is related to perceptual processing: A case from color perception

PubMed Central

Allen, Elizabeth C.; Beilock, Sian L.; Shevell, Steven K.

2011-01-01

We explored the relation between individual differences in working memory (WM) and color constancy, the phenomenon of color perception that allows us to perceive the color of an object as relatively stable under changes in illumination. Successive color constancy (measured by first viewing a colored surface under a particular illumination and later recalling it under a new illumination) was better for higher-WM individuals than for lower-WM individuals. Moreover, the magnitude of this WM difference depended on how much contextual information was available in the scene, which typically improves color constancy. By contrast, simple color memory, measured by viewing and recalling a colored surface under the same illumination, showed no significant relation to WM. This study reveals a relation between WM and a low-level perceptual process not previously thought to operate within the confines of attentional control, and provides a first account of the individual differences in color constancy known about for decades. PMID:21480748

Large inter-individual and intra-individual variability in the effect of perceptual load

PubMed Central

Yeshurun, Yaffa

2017-01-01

This study examined whether the recurrent difficulty to replicate results obtained with paradigms measuring distractor processing as a function of perceptual load is due to individual differences. We first reanalyzed, at the individual level, the data of eight previously reported experiments. These reanalyses revealed substantial inter-individual differences, with particularly low percentage of participants whose performance matched the load theory’s predictions (i.e., larger distractor interference with low than high levels of load). Moreover, frequently the results were opposite to the theory's predictions–larger interference in the high than low load condition; and often a reversed compatibility effect emerged–better performance in the incompatible than neutral condition. Subsequently, seven observers participated in five identical experimental sessions. If the observed inter-individual differences are due to some stable trait or perceptual capacity, similar results should have emerged in all sessions of a given participant. However, all seven participants showed large between-sessions variations with similar patterns to those found between participants. These findings question the theoretical foundation implemented with these paradigms, as none of the theories suggested thus far can account for such inter- and intra-individual differences. Thus, these paradigms should be used with caution until further research will provide better understanding of what they actually measure. PMID:28406997

Evolutionarily stable learning schedules and cumulative culture in discrete generation models.

PubMed

Aoki, Kenichi; Wakano, Joe Yuichiro; Lehmann, Laurent

2012-06-01

Individual learning (e.g., trial-and-error) and social learning (e.g., imitation) are alternative ways of acquiring and expressing the appropriate phenotype in an environment. The optimal choice between using individual learning and/or social learning may be dictated by the life-stage or age of an organism. Of special interest is a learning schedule in which social learning precedes individual learning, because such a schedule is apparently a necessary condition for cumulative culture. Assuming two obligatory learning stages per discrete generation, we obtain the evolutionarily stable learning schedules for the three situations where the environment is constant, fluctuates between generations, or fluctuates within generations. During each learning stage, we assume that an organism may target the optimal phenotype in the current environment by individual learning, and/or the mature phenotype of the previous generation by oblique social learning. In the absence of exogenous costs to learning, the evolutionarily stable learning schedules are predicted to be either pure social learning followed by pure individual learning ("bang-bang" control) or pure individual learning at both stages ("flat" control). Moreover, we find for each situation that the evolutionarily stable learning schedule is also the one that optimizes the learned phenotype at equilibrium. Copyright © 2012 Elsevier Inc. All rights reserved.

Transitions of Developmental Trajectories of Depressive Symptoms Between Junior and Senior High School Among Youths in Taiwan: Linkages to Symptoms in Young Adulthood.

PubMed

Wang, Yu-Chung Lawrence; Chan, Hsun-Yu; Chen, Pei-Chun

2018-02-21

We investigated the heterogeneous developmental trajectories of depressive symptoms in junior and senior high school, the transitions to different trajectories after entering senior high school, and the linkages to the development of depressive symptoms in early adulthood among Taiwanese adolescents. An eight-wave longitudinal data set was analyzed, including 2687 Taiwanese adolescents (51.2% boys, M age = 14.3 at first wave). Using a manual three-step latent transition growth mixture model, we found that a three-class solution fit the data for both junior high school (termed high-improving, cumulative, and JS-low-stable) and senior high school period (termed heightening, moderate-stable, and HS-low-stable). The depressive symptoms of most individuals maintained at a low level (i.e., low-stable) from adolescence to early adulthood; however, nearly a quarter of the adolescents reported depressive symptoms that were moderately or highly severe in senior high school and beyond. More than 30% of the participants experienced transitioning into a different developmental trajectory between junior and senior high school. When perceiving a higher level of paternal behavioral control, adolescents categorized in the high-improving class in junior high school would have a higher chance to transition to the moderate-stable class than to HS-low-stable class in senior high school. Adolescent boys and girls did not differ in the probability of transitioning between trajectories across junior and senior high school. However, a clear and consistent pattern of symptoms between late adolescence and early adulthood was not observed. These results help elucidate the heterogeneity and fluidity associated with the development of depressive symptoms between early adolescence and early adulthood in light of school transition among youths in Taiwan.

Group and individual stability of three parenting dimensions

PubMed Central

2011-01-01

Background The Parental Bonding Instrument, present self-report version, (PBI-PCh) includes three scales, Warmth, Protectiveness and Authoritarianism, which describe three dimensions of current parenting. The purposes of this study were to (1) evaluate the true and observed stability of these parenting dimensions related to older children, (2) explore the distribution of individual-level change across nine months and (3) test potential parental predictors of parenting instability. Methods Questionnaires were distributed to school-based samples of community parents of both genders (n = 150) twice, nine months apart. These questionnaires measured parenting, parental personality and emotional symptoms. Results Based on 1) stability correlations, 2) true stability estimates from structural equation modeling (SEM) and 3) distribution of individual-level change, Warmth appeared rather stable, although not as stable as personality traits. Protectiveness was moderately stable, whereas Authoritarianism was the least stable parenting dimension among community parents. The differences in stability between the three dimensions were consistent in both estimated true stability and observed stability. Most of the instability in Warmth originated from a minority of parents with personality, childhood care characteristics and lower current parenting warmth. For the Protectiveness dimension, instability was associated with higher Protectiveness scores. Conclusions True instability with all three self-reported parenting dimensions can occur across nine months in a community sample related to older children (7-15), but it may occur with varying degrees among dimensions and subpopulations. The highest stability was found for the Warmth parenting dimension, but a subgroup of "unstably cold" parents could be identified. Stability needs to be taken into account when interpreting longitudinal research on parenting and when planning and evaluating parenting interventions in research and clinical practice. PMID:21609442

Social exclusion: the interplay of group goals and individual characteristics.

PubMed

Richardson, Cameron B; Hitti, Aline; Mulvey, Kelly Lynn; Killen, Melanie

2014-08-01

Past research has shown that adolescents justify social exclusion based on concerns for group functioning, and yet, to date, no study has evaluated whether group functioning justifications shift or remain stable across different exclusion contexts. In this study, we systematically manipulated exclusion context (i.e., competitive or noncompetitive soccer groups) and individual characteristics of the target of exclusion to test the nature of the interaction between these factors during exclusion judgments. Adolescents' (N = 201; 61% Female) exclusion judgments differed across contexts only when an individual's ability was under consideration. Intergroup (i.e., gender, nationality) and interpersonal (i.e., aggression, shyness) characteristics overwhelmed contextual considerations. Results indicate the complexity of factors weighed by adolescents when making exclusion judgments, and suggest the need for extension of the present findings to understand more fully the interaction between the context of exclusion and individual characteristics in exclusion judgments.

Metabolite ratios to assumed stable creatine level may confound the quantification of proton brain MR spectroscopy.

PubMed

Li, Belinda S Y; Wang, Hao; Gonen, Oded

2003-10-01

In localized brain proton MR spectroscopy ((1)H-MRS), metabolites' levels are often expressed as ratios, rather than as absolute concentrations. Frequently, their denominator is the creatine [Cr], which level is explicitly assumed to be stable in normal as well as in many pathologic states. The rationale is that ratios self-correct for imager and localization method differences, gain instabilities, regional susceptibility variations and partial volume effects. The implicit assumption is that these benefits are worth their cost(w)-(w) propagation of the individual variation of each of the ratio's components. To test this hypothesis, absolute levels of N-acetylaspartate [NAA], choline [Cho] and [Cr] were quantified in various regions of the brains of 8 volunteers, using 3-dimensional (3D) (1)H-MRS at 1.5 T. The results show that in over 50% of approximately 2000 voxels examined, [NAA]/[Cr] and [Cho]/[Cr] exhibited higher coefficients of variations (CV) than [NAA] and [Cho] individually. Furthermore, in approximately 33% of these voxels, the ratios' CVs exceeded even the combined constituents' CVs. Consequently, basing metabolite quantification on ratios and assuming stable [Cr] introduces more variability into (1)H-MRS than it prevents. Therefore, its cost exceeds the benefit.

From heavy-tailed to exponential distribution of interevent time in cellphone top-up behavior

NASA Astrophysics Data System (ADS)

Wang, Peng; Ma, Qiang

2017-05-01

Cellphone top-up is a kind of activities, to a great extent, driven by individual consumption rather than personal interest and this behavior should be stable in common sense. However, our researches find there are heavy-tails both in interevent time distribution and purchase frequency distribution at the global level. Moreover, we find both memories of interevent time and unit price series are negative, which is different from previous bursty activities. We divide individuals into five groups according to the purchase frequency and the average unit price respectively. Then, the group analysis shows some significant heterogeneity in this behavior. On one hand, we obtain only the individuals with high purchase frequency have the heavy-tailed nature in interevent time distribution. On the contrary, the negative memory is only caused by low purchase-frequency individuals without burstiness. On the other hand, the individuals with different preferential price also have different power-law exponents at the group level and there is no data collapse after rescaling between these distributions. Our findings produce the evidence for the significant heterogeneity of human activity in many aspects.

Expertise Effects in Face-Selective Areas are Robust to Clutter and Diverted Attention, but not to Competition.

PubMed

McGugin, Rankin Williams; Van Gulick, Ana E; Tamber-Rosenau, Benjamin J; Ross, David A; Gauthier, Isabel

2015-09-01

Expertise effects for nonface objects in face-selective brain areas may reflect stable aspects of neuronal selectivity that determine how observers perceive objects. However, bottom-up (e.g., clutter from irrelevant objects) and top-down manipulations (e.g., attentional selection) can influence activity, affecting the link between category selectivity and individual performance. We test the prediction that individual differences expressed as neural expertise effects for cars in face-selective areas are sufficiently stable to survive clutter and manipulations of attention. Additionally, behavioral work and work using event related potentials suggest that expertise effects may not survive competition; we investigate this using functional magnetic resonance imaging. Subjects varying in expertise with cars made 1-back decisions about cars, faces, and objects in displays containing one or 2 objects, with only one category attended. Univariate analyses suggest car expertise effects are robust to clutter, dampened by reducing attention to cars, but nonetheless more robust to manipulations of attention than competition. While univariate expertise effects are severely abolished by competition between cars and faces, multivariate analyses reveal new information related to car expertise. These results demonstrate that signals in face-selective areas predict expertise effects for nonface objects in a variety of conditions, although individual differences may be expressed in different dependent measures depending on task and instructions. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

Moran, James J.; Ehrhardt, Christopher J.; Wahl, Jon H.

We analyzed 21 neat acetone samples from 15 different suppliers to demonstrate the utility of a coupled stable isotope and trace contaminant strategy for distinguishing forensically-relevant samples. By combining these two pieces of orthogonal data we could discriminate all of the acetones that were produced by the 15 different suppliers. Using stable isotope ratios alone, we were able to distinguish 9 acetone samples, while the remaining 12 fell into four clusters with highly similar signatures. Adding trace chemical contaminant information enhanced discrimination to 13 individual acetones with three residual clusters. The acetones within each cluster shared a common manufacturer andmore » might, therefore, not be expected to be resolved. The data presented here demonstrates the power of combining orthogonal data sets to enhance sample fingerprinting and highlights the role disparate data could play in future forensic investigations.« less

24-Hour protein, arginine and citrulline metabolism in fed critically ill children – a stable isotope tracer study

PubMed Central

de Betue, Carlijn T.I.; Garcia Casal, Xiomara C.; van Waardenburg, Dick A.; Schexnayder, Stephen M.; Joosten, Koen F.M.; Deutz, Nicolaas E.P.; Engelen, Marielle P.K.J.

2017-01-01

Background & aims The reference method to study protein and arginine metabolism in critically ill children is measuring plasma amino acid appearances with stable isotopes during a short (4–8h) time period and extrapolate results to 24-hour. However, 24-hour measurements may be variable due to critical illness related factors and a circadian rhythm could be present. Since only short duration stable isotope studies in critically ill children have been conducted before, the aim of this study was to investigate 24-hour appearance of specific amino acids representing protein and arginine metabolism, with stable isotope techniques in continuously fed critically ill children. Methods In eight critically ill children, admitted to the pediatric (n=4) or cardiovascular (n=4) intensive care unit, aged 0–10 years, receiving continuous (par)enteral nutrition with protein intake 1.0–3.7 g/kg/day, a 24-hour stable isotope tracer protocol was carried out. L-[ring-2H5]-phenylalanine, L-[3,3-2H2]-tyrosine, L-[5,5,5-2H3]-leucine, L-[guanido-15N2]-arginine and L-[5-13C-3,3,4,4-2H4]-citrulline were infused intravenously and L-[15N]-phenylalanine and L-[1-13C]leucine enterally. Arterial blood was sampled every hour. Results Coefficients of variation, representing intra-individual variability, of the amino acid appearances of phenylalanine, tyrosine, leucine, arginine and citrulline were high, on average 14–19% for intravenous tracers and 23–26% for enteral tracers. No evident circadian rhythm was present. The pattern and overall 24-hour level of whole body protein balance differed per individual. Conclusions In continuously fed stable critically ill children, the amino acid appearances of phenylalanine, tyrosine, leucine, arginine and citrulline show high variability. This should be kept in mind when performing stable isotope studies in this population. There was no apparent circadian rhythm. PMID:28089618

Airway clearance techniques for bronchiectasis.

PubMed

Lee, Annemarie L; Burge, Angela T; Holland, Anne E

2015-11-23

People with non-cystic fibrosis bronchiectasis commonly experience chronic cough and sputum production, features that may be associated with progressive decline in clinical and functional status. Airway clearance techniques (ACTs) are often prescribed to facilitate expectoration of sputum from the lungs, but the efficacy of these techniques in a stable clinical state or during an acute exacerbation of bronchiectasis is unclear. Primary: to determine effects of ACTs on rates of acute exacerbation, incidence of hospitalisation and health-related quality of life (HRQoL) in individuals with acute and stable bronchiectasis. Secondary: to determine whether:• ACTs are safe for individuals with acute and stable bronchiectasis; and• ACTs have beneficial effects on physiology and symptoms in individuals with acute and stable bronchiectasis. We searched the Cochrane Airways Group Specialised Register of trials from inception to November 2015 and PEDro in March 2015, and we handsearched relevant journals. Randomised controlled parallel and cross-over trials that compared an ACT versus no treatment, sham ACT or directed coughing in participants with bronchiectasis. We used standard methodological procedures as expected by The Cochrane Collaboration. Seven studies involving 105 participants met the inclusion criteria of this review, six of which were cross-over in design. Six studies included adults with stable bronchiectasis; the other study examined clinically stable children with bronchiectasis. Three studies provided single treatment sessions, two lasted 15 to 21 days and two were longer-term studies. Interventions varied; some control groups received a sham intervention and others were inactive. The methodological quality of these studies was variable, with most studies failing to use concealed allocation for group assignment and with absence of blinding of participants and personnel for outcome measure assessment. Heterogeneity between studies precluded inclusion of these data in the meta-analysis; the review is therefore narrative.One study including 20 adults that compared an airway oscillatory device versus no treatment found no significant difference in the number of exacerbations at 12 weeks (low-quality evidence). Data were not available for assessment of the impact of ACTs on time to exacerbation, duration or incidence of hospitalisation or total number of hospitalised days. The same study reported clinically significant improvements in HRQoL on both disease-specific and cough-related measures. The median difference in the change in total St George's Respiratory Questionnaire (SGRQ) score over three months in this study was 7.5 units (P value = 0.005 (Wilcoxon)). Treatment consisting of high-frequency chest wall oscillation (HFCWO) or a mix of ACTs prescribed for 15 days significantly improved HRQoL when compared with no treatment (low-quality evidence). Two studies reported mean increases in sputum expectoration with airway oscillatory devices in the short term of 8.4 mL (95% confidence interval (CI) 3.4 to 13.4 mL) and in the long term of 3 mL (P value = 0.02). HFCWO improved forced expiratory volume in one second (FEV1) by 156 mL and forced vital capacity (FVC) by 229.1 mL when applied for 15 days, but other types of ACTs showed no effect on dynamic lung volumes. Two studies reported a reduction in pulmonary hyperinflation among adults with non-positive expiratory pressure (PEP) ACTs (difference in functional residual capacity (FRC) of 19%, P value < 0.05; difference in total lung capacity (TLC) of 703 mL, P value = 0.02) and with airway oscillatory devices (difference in FRC of 30%, P value < 0.05) compared with no ACTs. Low-quality evidence suggests that ACTs (HFCWO, airway oscillatory devices or a mix of ACTs) reduce symptoms of breathlessness and cough and improve ease of sputum expectoration compared with no treatment (P value < 0.05). ACTs had no effect on gas exchange, and no studies reported effects of antibiotic usage. Among studies exploring airway oscillating devices, investigators reported no adverse events. ACTs appear to be safe for individuals (adults and children) with stable bronchiectasis and may account for improvements in sputum expectoration, selected measures of lung function, symptoms and HRQoL. The role of these techniques in acute exacerbation of bronchiectasis is unknown. In view of the chronic nature of bronchiectasis, additional data are needed to establish the short-term and long-term clinical value of ACTs for patient-important outcomes and for long-term clinical parameters that impact disease progression in individuals with stable bronchiectasis, allowing further guidance on prescription of specific ACTs for people with bronchiectasis.

A retrospective analysis of pollen host plant use by stable and declining bumble bee species.

PubMed

Kleijn, David; Raemakers, Ivo

2008-07-01

Understanding population declines has been the objective of a wide range of ecological studies. When species have become rare such studies are complicated because particular behavior or life history traits may be the cause but also the result of the decline of a species. We approached this problem by studying species' characteristics on specimens that were collected before the onset of their decline and preserved in natural history museums. In northwestern Europe, some bumble bee species declined dramatically during the 20th century whereas other, ecologically similar, species maintained stable populations. A long-standing debate focuses on whether this is caused by declining species having stricter host plant preferences. We compared the composition of pollen loads of five bumble bee species with stable populations and five with declining populations using museum specimens collected before 1950 in Belgium, England, and The Netherlands. Prior to 1950, the number of plant taxa in pollen loads of declining species was almost one-third lower than that in stable species even though individuals of stable and declining species generally originated from the same areas. There were no systematic differences in the composition of pollen loads between stable and declining species, but the plant taxa preferred by declining species before 1950 had experienced a stronger decline in the 20th century than those preferred by stable species. In 2004 and 2005, we surveyed the areas where bumble bees had been caught in the past and compared the composition of past and present pollen loads of the stable, but not of the by now locally extinct declining species. The number of collected pollen taxa was similar, but the composition differed significantly between the two periods. Differences in composition reflected the major changes in land use in northwestern Europe but also the spread of the invasive plant species Impatiens glandulifera. The main question now is why declining species apparently were not able to switch to less preferred food plants when stable species were. This study shows that natural history collections can play an important role in improving our understanding of the ecological mechanisms driving species population change.

Evaluating cleansing effects on trace elements and stable isotope values in feathers of oiled birds.

PubMed

Valladares, Sonia; Moreno, Roćio; Jover, Lluis; Sanpera, Carola

2010-01-01

Feathers of seabirds are widely used as a nondestructive tissue for pollution monitoring of trace elements, as well as convenient samples for trophic ecology studies by means of stable isotope analysis (SIA). Nevertheless, feathers can be occasionally impregnated with oil from deliberate ship discharges and from massive oil spill accidents. The feather structure makes them effective traps for particles and are subject to external contamination. It is unknown to what extent the oil adhered to feathers can change trace element concentrations or stable isotope signatures. This study has two primary objectives: (1) to assess if there are differences between trace element concentrations and stable isotope signatures of oiled and clean feathers, and (2) to determine if the cleansing of oiled feathers using commonly applied techniques such as sodium hydroxide (NaOH) washes in combination with an organic solvent (hexane) is more effective than using NaOH alone. In order to do this, we analysed trace elements (Se, Hg, Pb, Cu and Zn) and stable isotopes (delta(13)C and delta(15)N) of individual feathers of yellow-legged gulls (Larus michahellis) which were affected by the 2002 Prestige oil spill in Galicia (NW Spain). Two sets of feathers were analysed, one group were oil-free (Control group) and the other had oil adhered to its surface (Oiled group). We expected to find differences between control and oiled feathers when cleaning exclusively with NaOH and no differences when using hexane. Our results did not show significant differences between Control and Oiled groups as a consequence of the cleansing method used. Unexpectedly, the additional cleansing with hexane resulted in decreasing selenium concentrations and increasing zinc and delta(15)N values in all groups of feathers.

INDIVIDUAL DIFFERENCES IN ORAL NICOTINE INTAKE IN RATS

PubMed Central

Nesil, Tanseli; Kanit, Lutfiye; Collins, Allan C; Pogun, Sakire

2011-01-01

To study individual differences in nicotine preference and intake, male and female rats were given free access to a choice of oral nicotine (10 or 20 mg/L) or water for 24 hours/day for periods of at least six weeks, starting at adolescence or adulthood. A total of 341 rats, were used in four different experiments; weight, nicotine intake and total liquid consumption were recorded weekly. Results show that rats can discriminate nicotine from water, can regulate their intake, and that there are readily detected individual differences in nicotine preference. Ward analyses indicated that the animals could be divided into minimum, median and maximum preferring subgroups in all experiments. The effect of saccharine on nicotine intake was also evaluated; although the addition of saccharine increased total intake, rats drank unsweetened nicotine solutions and those with higher preferences for nicotine, preferred nicotine over water with or without saccharine added. Nicotine reduced weight gain and the effect was more pronounced in females than males. The average nicotine consumption of adolescent rats was higher than adults and nicotine exposure during adolescence reduced nicotine intake in adult rats. About half of the rats which had access to nicotine as adolescents and also as adults had a persistent pattern of consumption; the behavior was very stable in the female minimum preferring groups and a much higher ratio of rats sustained their adolescent behavior as adults. The change in preference was more pronounced when there was an interval between adolescent and adult exposure; female rats showed a more stable behavior than males suggesting a greater role for environmental influences on males. In conclusion, marked individual differences were observed in oral nicotine intake as measured in a continuous access 2-bottle choice test. Age and sex of the subjects and previous exposure to nicotine are significant factors which affect preference in rats. PMID:21504750

What Process Mediates Predictions of Childhood IQ from Infant Habituation and Recognition Memory? Speculations on the Roles of Inhibition and Rate of Information Processing.

ERIC Educational Resources Information Center

McCall, Robert B.

1994-01-01

This editorial proposes that the dependent variables that predict childhood intelligence quotient (IQ) from habituation and recognition memory assessments made during infancy may primarily reflect individual differences in rate of information processing. Inhibition may be a stable thread in mental development. (Author/SLD)

Dampening of Adrenocortical Responses during Infancy: Normative Changes and Individual Differences.

ERIC Educational Resources Information Center

Gunnar, Megan R.; And Others

1996-01-01

Examined changes in cortisol and behavioral responses in 83 infants. Found that salivary cortisol responses before and after inoculation were high at 2 months, decreased between 2 and 4 months, remained stable, then declined again between 6 and 15 months. Found some evidence that emergence of circadian rhythm in cortisol might be related to early…

Growth and Decline in Language and Phonological Memory over Two Years among Adolescents with Down Syndrome

ERIC Educational Resources Information Center

Conners, Frances A.; Tungate, Andrew S.; Abbeduto, Leonard; Merrill, Edward C.; Faught, Gayle G.

2018-01-01

Forty-two adolescents with Down syndrome (DS) ages 10 to 21 years completed a battery of language and phonological memory measures twice, 2 years apart. Individual differences were highly stable across two years. Receptive vocabulary scores improved, there was no change in receptive or expressive grammar scores, and nonword repetition scores…

The Development of Sex-Gender Constancy Among Children in Four Cultures.

ERIC Educational Resources Information Center

Munroe, Ruth H.; Munroe, Robert L.

The study examines the acquisition of gender constancy in children as it relates to cultural, socioenvironmental, or individual differences. Gender constancy refers to the stages from simple identification of biological sex of self and others, to the understanding that one's sex is stable over time, and to comprehension of one's sex as consistent…

Dynamics and optimal control of a non-linear epidemic model with relapse and cure

NASA Astrophysics Data System (ADS)

Lahrouz, A.; El Mahjour, H.; Settati, A.; Bernoussi, A.

2018-04-01

In this work, we introduce the basic reproduction number R0 for a general epidemic model with graded cure, relapse and nonlinear incidence rate in a non-constant population size. We established that the disease free-equilibrium state Ef is globally asymptotically exponentially stable if R0 < 1 and globally asymptotically stable if R0 = 1. If R0 > 1, we proved that the system model has at least one endemic state Ee. Then, by means of an appropriate Lyapunov function, we showed that Ee is unique and globally asymptotically stable under some acceptable biological conditions. On the other hand, we use two types of control to reduce the number of infectious individuals. The optimality system is formulated and solved numerically using a Gauss-Seidel-like implicit finite-difference method.

Persistence of Space Radiation Induced Cytogenetic Damage in the Blood Lymphocytes of Astronauts

NASA Technical Reports Server (NTRS)

George, Kerry; Cucinotta, Francis A.

2008-01-01

Cytogenetic damage in astronaut's peripheral blood lymphocytes is a useful in vivo marker of space radiation induced damage. Moreover, if radiation induced chromosome translocations persist in peripheral blood lymphocytes for many years, as has been assumed, they could potentially be used to measure retrospective doses or prolonged low dose rate exposures. However, as more data becomes available, evidence suggests that the yield of translocations may decline with time after exposure, at least in the case of space radiation exposures. We present our latest follow-up measurements of chromosome aberrations in astronauts blood lymphocytes assessed by FISH painting and collected a various times beginning directly after return from space to several years after flight. For most individuals the analysis of individual time-courses for translocations revealed a temporal decline of yields with different half-lives. Since the level of stable aberrations depends on the interplay between natural loss of circulating T-lymphocytes and replenishment from the stem or progenitor cells, the differences in the rates of decay could be explained by inter-individual variation in lymphocyte turn over. Biodosimetry estimates derived from cytogenetic analysis of samples collected a few days after return to earth lie within the range expected from physical dosimetry. However, a temporal decline in yields may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure. In addition, limited data on multiple flights show a lack of correlation between time in space and translocation yields. Data from one crewmember who has participated in two separate long-duration space missions and has been followed up for over 10 years provides limited information on the effect of repeat flights and show a possible adaptive response to space radiation exposure.

Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation

PubMed Central

Maire, Micheline; Reichert, Carolin F.; Gabel, Virginie; Viola, Antoine U.; Krebs, Julia; Strobel, Werner; Landolt, Hans-Peter; Bachmann, Valérie; Cajochen, Christian; Schmidt, Christina

2014-01-01

Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3). By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition) and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition) in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER35/5) experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses) in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER34/4). These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioral vulnerability. PMID:24639634

Individual consistency and flexibility in human social information use.

PubMed

Toelch, Ulf; Bruce, Matthew J; Newson, Lesley; Richerson, Peter J; Reader, Simon M

2014-02-07

Copying others appears to be a cost-effective way of obtaining adaptive information, particularly when flexibly employed. However, adult humans differ considerably in their propensity to use information from others, even when this 'social information' is beneficial, raising the possibility that stable individual differences constrain flexibility in social information use. We used two dissimilar decision-making computer games to investigate whether individuals flexibly adjusted their use of social information to current conditions or whether they valued social information similarly in both games. Participants also completed established personality questionnaires. We found that participants demonstrated considerable flexibility, adjusting social information use to current conditions. In particular, individuals employed a 'copy-when-uncertain' social learning strategy, supporting a core, but untested, assumption of influential theoretical models of cultural transmission. Moreover, participants adjusted the amount invested in their decision based on the perceived reliability of personally gathered information combined with the available social information. However, despite this strategic flexibility, participants also exhibited consistent individual differences in their propensities to use and value social information. Moreover, individuals who favoured social information self-reported as more collectivist than others. We discuss the implications of our results for social information use and cultural transmission.

Individual consistency and flexibility in human social information use

PubMed Central

Toelch, Ulf; Bruce, Matthew J.; Newson, Lesley; Richerson, Peter J.; Reader, Simon M.

2014-01-01

Copying others appears to be a cost-effective way of obtaining adaptive information, particularly when flexibly employed. However, adult humans differ considerably in their propensity to use information from others, even when this ‘social information’ is beneficial, raising the possibility that stable individual differences constrain flexibility in social information use. We used two dissimilar decision-making computer games to investigate whether individuals flexibly adjusted their use of social information to current conditions or whether they valued social information similarly in both games. Participants also completed established personality questionnaires. We found that participants demonstrated considerable flexibility, adjusting social information use to current conditions. In particular, individuals employed a ‘copy-when-uncertain’ social learning strategy, supporting a core, but untested, assumption of influential theoretical models of cultural transmission. Moreover, participants adjusted the amount invested in their decision based on the perceived reliability of personally gathered information combined with the available social information. However, despite this strategic flexibility, participants also exhibited consistent individual differences in their propensities to use and value social information. Moreover, individuals who favoured social information self-reported as more collectivist than others. We discuss the implications of our results for social information use and cultural transmission. PMID:24352950

Does personality in small rodents vary depending on population density?

PubMed

Korpela, Katri; Sundell, Janne; Ylönen, Hannu

2011-01-01

Personality means an individual's unique way of behaving and reacting to the environment. It is a stable and heritable trait, which is expressed consistently in different situations. The aim of our study was to develop novel tests to depict the personality structure of the bank vole Myodes glareolus, and to determine if the phase of the population cycle, i.e. population density, affects personality. We focused on some central aspects of bank vole behaviour: mobility, risk taking, exploratory behaviour, dominance, and aggressive behaviour towards pups. These behaviours were chosen because they directly affect bank vole survival or fitness or are classified as important factors of personality in other species. In total, 192 males from different populations went through four behavioural tests, in which 20 variables were measured. The tests were repeated after 3 weeks, which verified that all traits were stable, i.e. repeatable between trials. Three personality compounds emerged, named extroversion, novelty seeking and infanticide. Extroversion included dominance and mobility, while novelty seeking consisted of risk taking and exploration. Infanticide encompassed all indices measuring harmful behaviour towards pups. Mobility and dominance were connected, possibly because both seem to depend on condition. Time spent in captivity increased extroversion, which may be explained by good food, stable conditions and acclimation to strong social cues. Novelty seeking was connected to repeatability which could mean that novelty avoiding individuals adjust their behaviour to match new environments. Population density affected the infanticide trait but not novelty seeking or extroversion.

Longitudinal trajectories of intellectual and adaptive functioning in adolescents and adults with Williams syndrome.

PubMed

Fisher, M H; Lense, M D; Dykens, E M

2016-10-01

Williams syndrome (WS) is associated with a distinct cognitive-behavioural phenotype including mild to moderate intellectual disability, visual-spatial deficits, hypersociability, inattention and anxiety. Researchers typically characterise samples of individuals with WS by their intellectual functioning and adaptive behaviour. Because of the low prevalence of the syndrome, researchers often include participants with WS across a broad age range throughout childhood and adulthood and assume participants demonstrate consistent cognitive development across ages. Indeed, IQ scores are generally stable for children and adolescents with WS, although there are significant individual differences. It is less clear whether this pattern of stable intellectual ability persists into adulthood. Furthermore, while adaptive behaviour is an important indicator of an individual's ability to apply their conceptual skills to everyday functioning, conflicting findings on the trajectories of adaptive behaviour in adolescents and adults with WS have been reported. The current study examined longitudinal profiles of cognitive and adaptive functioning in adolescents and adults with WS. To examine cognitive functioning, participants included 52 individuals with WS (51.9% men) who were assessed with the Kaufman Brief Intelligence Test, 2nd edition (KBIT-2) between two and seven times. At their first assessment, participants had a mean age of 25.4 years (SD = 8.4), ranging in age from 14.2 to 48.9 years. To assess adaptive behaviour, participants included a subset of 28 individuals with WS whose parents completed the Vineland Adaptive Behavior Scale, 2nd edition (VABS-II) between two and five times. At their initial administration, participants ranged from 17.1-40.2 years of age, with a mean age of 26.5 years (SD = 7.3). A series of multilevel models were used to examine changes in KBIT-2 Composite IQ, Verbal IQ and Nonverbal IQ standard scores over time, as well as the Adaptive Behavior Composite, and the Communication, Daily Living Skills and Socialization subdomains of the VABS-II. Consistent with the WS cognitive profile, IQ scores were significantly lower than the general population IQ score of 100, and there was significant variability in individual IQ scores and slopes. KBIT-2 IQ scores were generally stable across adolescents and adults with WS. Adaptive behaviour scores were significantly lower than the population mean score of 100, and there was significant variability in individuals' adaptive behaviour scores but not trajectories. However, in contrast to the findings with the KBIT-2, VABS-II scores were observed to significantly decrease over time. Findings suggest that while intellectual functioning remains stable, adaptive functioning does not remain stable across adolescence and adulthood in individuals with WS. Implications for the relation between cognitive and adaptive functioning across development are discussed, with a focus on how this relates to specific aspects of the WS phenotype. © 2016 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

The Wang Landau parallel algorithm for the simple grids. Optimizing OpenMPI parallel implementation

NASA Astrophysics Data System (ADS)

Kussainov, A. S.

2017-12-01

The Wang Landau Monte Carlo algorithm to calculate density of states for the different simple spin lattices was implemented. The energy space was split between the individual threads and balanced according to the expected runtime for the individual processes. Custom spin clustering mechanism, necessary for overcoming of the critical slowdown in the certain energy subspaces, was devised. Stable reconstruction of the density of states was of primary importance. Some data post-processing techniques were involved to produce the expected smooth density of states.

Uniform diet in a diverse society. Revealing new dietary evidence of the Danish Roman Iron Age based on stable isotope analysis.

PubMed

Jørkov, Marie Louise S; Jørgensen, Lars; Lynnerup, Niels

2010-12-01

A systematic dietary investigation during Danish Roman Iron Age (1-375AD) is conducted by analyzing stable isotope ratios of carbon (δ(13) C) and nitrogen (δ(15) N) in the collagen of human and animal bone. The human sample comprises 77 individuals from 10 burial sites. In addition 31 samples of mammals and fish were analyzed from same geographical area. The investigation characterizes the human diet among different social groupings and analyses dietary differences present between sex, age, and site phase groups. Diachronically, the study investigates the Roman influences that had an effect on social structure and subsistence economy in both the Early and Late Period. Geographically the locations are both inland and coastal. The isotopic data indicate extremely uniform diet both between and within population groups from Early and Late Roman periods and the data are consistent throughout the Roman Iron Age. Protein consumption was dominated by terrestrial animals with no differences among social status, age, sex, or time period, while terrestrial plant protein only seems to have contributed little in the diet. Furthermore, the consumption of marine or aquatic resources does not seem to have been important, even among the individuals living next to the coast. Copyright © 2010 Wiley-Liss, Inc.

Retirement is associated with change in self-esteem.

PubMed

Bleidorn, Wiebke; Schwaba, Ted

2018-05-07

We examined the course of self-esteem during the transition to retirement in a sample of 690 retirees (ages 51-81) and a propensity-score matched-comparison group of 515 nonretirees drawn from a nationally representative longitudinal study in the Netherlands. The average retiree decreased in self-esteem in the 5 years before retirement and remained stable in self-esteem in the 5 years following retirement. We also found significant individual differences in retirees' self-esteem trajectories but failed to identify moderators that may account for these individual differences. We discuss the implications of these results for theory and future research on life span self-esteem development. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Stability analysis of oil yield in oil palm (Elaeis guineensis) progenies in different environments.

PubMed

Rafii, M Y; Jalani, B S; Rajanaidu, N; Kushairi, A; Puteh, A; Latif, M A

2012-10-04

We evaluated 38 dura x pisifera (DP) oil palm progenies in four locations in Malaysia for genotype by environment interaction and genotypic stability studies. The DP progenies derived from crosses between pisifera palms of AVROS, Serdang S27B, Serdang 29/36, and Lever Cameroon were chosen to be the males' parent and Deli dura palms designated as females' parent. All the locations differed in terms of soil physical and chemical properties, and the soil types ranged from coastal clay to inland soils. The genotype by environment interaction and stability of the individual genotypes were analyzed for oil yield trait using several stability techniques. A genotype by environment interaction was detected for oil yield and it had a larger variance component than genotypic variance (σ(2)(gl)/σ(2)(g) = 139.7%). Genotype by environment interaction of oil yield was largely explained by a non-linear relationship between genotypic and environmental values. Overall assessment of individual genotypic stability showed that seven genotypes were highly stable and had consistent performance over the environments for the oil yield trait [total individual genotype stability scored more than 10 and mean oil yielded above the average of the environment (genotype means are more than 34.37 kg·palm(-1)·year(-1))]. These genotypes will be useful for oil palm breeding and tissue culture programs for developing high oil yielding planting materials with stable performance.

Isotopic Differences between Forage Consumed by a Large Herbivore in Open, Closed, and Coastal Habitats: New Evidence from a Boreal Study System.

PubMed

Giroux, Marie-Andrée; Valiquette, Éliane; Tremblay, Jean-Pierre; Côté, Steeve D

2015-01-01

Documenting habitat-related patterns in foraging behaviour at the individual level and over large temporal scales remains challenging for large herbivores. Stable isotope analysis could represent a valuable tool to quantify habitat-related foraging behaviour at the scale of individuals and over large temporal scales in forest dwelling large herbivores living in coastal environments, because the carbon (δ13C) or nitrogen (δ15N) isotopic signatures of forage can differ between open and closed habitats or between terrestrial and littoral forage, respectively. Here, we examined if we could detect isotopic differences between the different assemblages of forage taxa consumed by white-tailed deer that can be found in open, closed, supralittoral, and littoral habitats. We showed that δ13C of assemblages of forage taxa were 3.0 ‰ lower in closed than in open habitats, while δ15N were 2.0 ‰ and 7.4 ‰ higher in supralittoral and littoral habitats, respectively, than in terrestrial habitats. Stable isotope analysis may represent an additional technique for ecologists interested in quantifiying the consumption of terrestrial vs. marine autotrophs. Yet, given the relative isotopic proximity and the overlap between forage from open, closed, and supralittoral habitats, the next step would be to determine the potential to estimate their contribution to herbivore diet.

A study of distribution, sex differences and stability of lip print patterns in an Indian population.

PubMed

Kapoor, Neeti; Badiye, Ashish

2017-09-01

Lip prints are very useful in forensic investigations. The objective of this study is to determine predominant lip print pattern found among a central Indian population, to evaluate whether any sex difference exists and to study the permanence of the pattern over a 6 month duration. This study included 200 healthy adult subjects comprising of 100 males and 100 females in the age group of 18-25 years. A convenient and easier method of data collection i.e., digital photography was used instead of the traditional lipstick methods. Lip prints were then divided into four quadrants and recognized as per Suzuki and Tsuchihashi's classification. Type I (30.63%) was found to be most predominant overall in the Marathi population. Type I (29.75%) and Type III (35.75%) were found most prevalent in males and females respectively. Applying the Chi-Square test, statistically significant differences ( p  < 0.05) were observed between male and female lip print patterns in each of the quadrants individually and all quadrants taken together. The lip print patterns remained stable over a period of six-months. Being stable and with significant sex differences, lip prints can be effectively used as an important tool in forensic investigations for individualization as well as identification of sex of the donor, thus, narrowing down the scope of investigation to almost half.

Retest reliability of individual alpha ERD topography assessed by human electroencephalography.

PubMed

Vázquez-Marrufo, Manuel; Galvao-Carmona, Alejandro; Benítez Lugo, María Luisa; Ruíz-Peña, Juan Luis; Borges Guerra, Mónica; Izquierdo Ayuso, Guillermo

2017-01-01

Despite the immense literature related to diverse human electroencephalographic (EEG) parameters, very few studies have focused on the reliability of these measures. Some of the most studied components (i.e., P3 or MMN) have received more attention regarding the stability of their main parameters, such as latency, amplitude or topography. However, spectral modulations have not been as extensively evaluated considering that different analysis methods are available. The main aim of the present study is to assess the reliability of the latency, amplitude and topography of event-related desynchronization (ERD) for the alpha band (10-14 Hz) observed in a cognitive task (visual oddball). Topography reliability was analysed at different levels (for the group, within-subjects individually and between-subjects individually). The latency for alpha ERD showed stable behaviour between two sessions, and the amplitude exhibited an increment (more negative) in the second session. Alpha ERD topography exhibited a high correlation score between sessions at the group level (r = 0.903, p<0.001). The mean value for within-subject correlations was 0.750 (with a range from 0.391 to 0.954). Regarding between-subject topography comparisons, some subjects showed a highly specific topography, whereas other subjects showed topographies that were more similar to those of other subjects. ERD was mainly stable between the two sessions with the exception of amplitude, which exhibited an increment in the second session. Topography exhibits excellent reliability at the group level; however, it exhibits highly heterogeneous behaviour at the individual level. Considering that the P3 was previously evaluated for this group of subjects, a direct comparison of the correlation scores was possible, and it showed that the ERD component is less reliable in individual topography than in the ERP component (P3).

Retest reliability of individual alpha ERD topography assessed by human electroencephalography

PubMed Central

Vázquez-Marrufo, Manuel; Benítez Lugo, María Luisa; Ruíz-Peña, Juan Luis; Borges Guerra, Mónica; Izquierdo Ayuso, Guillermo

2017-01-01

Background Despite the immense literature related to diverse human electroencephalographic (EEG) parameters, very few studies have focused on the reliability of these measures. Some of the most studied components (i.e., P3 or MMN) have received more attention regarding the stability of their main parameters, such as latency, amplitude or topography. However, spectral modulations have not been as extensively evaluated considering that different analysis methods are available. The main aim of the present study is to assess the reliability of the latency, amplitude and topography of event-related desynchronization (ERD) for the alpha band (10–14 Hz) observed in a cognitive task (visual oddball). Topography reliability was analysed at different levels (for the group, within-subjects individually and between-subjects individually). Results The latency for alpha ERD showed stable behaviour between two sessions, and the amplitude exhibited an increment (more negative) in the second session. Alpha ERD topography exhibited a high correlation score between sessions at the group level (r = 0.903, p<0.001). The mean value for within-subject correlations was 0.750 (with a range from 0.391 to 0.954). Regarding between-subject topography comparisons, some subjects showed a highly specific topography, whereas other subjects showed topographies that were more similar to those of other subjects. Conclusion ERD was mainly stable between the two sessions with the exception of amplitude, which exhibited an increment in the second session. Topography exhibits excellent reliability at the group level; however, it exhibits highly heterogeneous behaviour at the individual level. Considering that the P3 was previously evaluated for this group of subjects, a direct comparison of the correlation scores was possible, and it showed that the ERD component is less reliable in individual topography than in the ERP component (P3). PMID:29088307

Stable isotope analysis of Dacryoconarid carbonate microfossils: a new tool for Devonian oxygen and carbon isotope stratigraphy.

PubMed

Frappier, Amy Benoit; Lindemann, Richard H; Frappier, Brian R

2015-04-30

Dacryoconarids are extinct marine zooplankton known from abundant, globally distributed calcite microfossils in the Devonian, but their shell stable isotope composition has not been previously explored. Devonian stable isotope stratigraphy is currently limited to less common invertebrates or bulk rock analyses of uncertain provenance. As with Cenozoic planktonic foraminifera, isotopic analysis of dacryoconarid shells could facilitate higher-resolution, geographically widespread stable isotope records of paleoenvironmental change, including marine hypoxia events, climate changes, and biocrises. We explored the use of Dacryoconarid isotope stratigraphy as a viable method in interpreting paleoenvironments. We applied an established method for determining stable isotope ratios (δ(13) C, δ(18) O values) of small carbonate microfossils to very well-preserved dacryoconarid shells. We analyzed individual calcite shells representing five common genera using a Kiel carbonate device coupled to a MAT 253 isotope ratio mass spectrometer. Calcite shell δ(13) C and δ(18) O values were compared by taxonomic group, rock unit, and locality. Single dacryoconarid calcite shells are suitable for stable isotope analysis using a Kiel-IRMS setup. The dacryoconarid shell δ(13) C values (-4.7 to 2.3‰) and δ(18) O values (-10.3 to -4.8‰) were consistent across taxa, independent of shell size or part, but varied systematically through time. Lower fossil δ(18) O values were associated with warmer water temperature and more variable δ(13) C values were associated with major bioevents. Dacryoconarid δ(13) C and δ(18) O values differed from bulk rock carbonate values. Dacryoconarid individual microfossil δ(13) C and δ(18) O values are highly sensitive to paleoenvironmental changes, thus providing a promising avenue for stable isotope chemostratigraphy to better resolve regional to global paleoceanographic changes throughout the upper Silurian to the upper Devonian. Our results warrant further exploration of dacryoconarid stable isotope proxy sensitivity, the isotopic contrast among dacryoconarids, other taxa, and bulk rock, as well as other potential dacryoconarid proxies (Mg/Ca, Sr/Ca, (87) Sr/(86) Sr, microlaser and ion microprobe isotope techniques, and clumped isotopes) for stratigraphic research. Copyright © 2015 John Wiley & Sons, Ltd.

English children as personality theorists: accounts of the modifiability, development, and origin of traits.

PubMed

Yuill, N

1997-02-01

Forty-eight children, 4, 6, 7, and 10 years old, were interviewed to assess their accounts of the modifiability, development, and origin of four character traits (grumpy, shy, mean, fussy) and two physical traits (fat, thin). The youngest children described traits as moderately controllable and usually stable, whereas for the 2 middle groups, physiological traits in particular were highly modifiable and less stable. Six-year-olds frequently cited preferences as sources of individual differences, possibly as a precursor to a fuller understanding of traits as internal, partly uncontrollable, and idiosyncratic attributes. Seven-year-olds were more likely to mention cognitively mediated accounts of personality change, as were 10-year-olds, who were also more aware of the interactive and variable nature of influences on personality. All age groups showed coherent patterns of trait explanation and used different models of explanation for different traits. The results suggest that a monolithic model of trait understanding is misleading, because the children used a variety of different models of development.

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.

PubMed

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.

Intergroup Variation of Social Relationships in Wild Vervet Monkeys: A Dynamic Network Approach.

PubMed

Borgeaud, Christèle; Sosa, Sebastian; Bshary, Redouan; Sueur, Cédric; van de Waal, Erica

2016-01-01

Social network analysis is a powerful tool that enables us to describe and quantify relationships between individuals. So far most of the studies rely on the analyses of various network snapshots, but do not capture changes over time. Here we use a stochastic actor-oriented model (SAOM) to test both the structure and the dynamics of relationships of three groups of wild vervet monkeys. We found that triadic closure (i.e., the friend of a friend is a friend) was significant in all three groups while degree popularity (i.e., the willingness to associate with individuals with high degree of connections) was significant in only two groups (AK, BD). The structure and dynamics of relationships according to the attributes of sex, matrilineand age differed significantly among groups. With respect to the structure, when analyzing the likelihood of bonds according to the different attributes, we found that individuals associate themselves preferably to individuals of the same sex only in two groups (AK, NH), while significant results for attachment to individuals of the same matriline were found also in two groups (BD, NH). With respect to the dynamics, i.e., how quickly relationships are modified, we found in two groups (AK, BD) that females' relationships were more prone to variation than males.' In the BD group, relationships within high-ranking matrilines were less stable than low-ranking ones while in the NH group, juveniles' relationships were also less stable than adults' ones. The intergroup variation indicates that establishing species-specific or even population specific characteristics of social networks for later between-species comparisons will be challenging. Although, such variation could also indicate some methodological issue, we are quite confident that data was collected similarly within the different groups. Our study therefore provides a potential new method to quantify social complexity according to natural demographic variation.

Habitat Use and Trophic Structure in a Highly Migratory Predatory Fish Identified with Geochemical Proxies in Scales

NASA Astrophysics Data System (ADS)

Seeley, M.; Walther, B. D.

2016-02-01

Atlantic tarpon, Megalops atlanticus, are highly migratory euryhaline predators that occupy different habitats throughout ontogeny. Specifically, Atlantic tarpon are known to inhabit oligohaline waters, although the frequency and duration of movements across estuarine gradients into these waters are relatively unknown. This species supports over a two billion dollar industry within the Gulf of Mexico and is currently listed as vulnerable under the International Union for the Conservation of Nature (IUCN). A new non-lethal method for reconstructing migrations across estuaries relies on trace element and stable isotope compositions of growth increments in scales. We analyzed Atlantic tarpon scales from the Texas coast to validate this method using inductively coupled plasma mass spectrometry (ICP-MS) for trace elements and isotope ratio mass spectrometry (IR-MS) for stable isotope ratios. Multiple scales were also taken from the same individual to confirm the consistency of elemental uptake within the same individual. Results show that scale Ba:Ca, Sr:Ca and δ13C are effective proxies for salinity, while enrichments in δ15N are consistent with known ontogenetic trophic shifts. In addition, chemical transects across multiple scales from the same individual were highly consistent, suggesting that any non-regenerated scale removed from a fish can provide equivalent time series. Continuous life history profiles of scales were obtained via laser ablation transects of scale cross-sections to quantify trace element concentrations from the core (youngest increments) to the edge (oldest increments). Stable isotope and trace element results together indicate that behavior is highly variable between individuals, with some but not all fish transiting estuarine gradients into oligohaline waters. Our findings will provide novel opportunities to investigate alternative non-lethal methods to monitor fish migrations across chemical gradients.

Estimating pathway-specific contributions to biodegradation in aquifers based on dual isotope analysis: theoretical analysis and reactive transport simulations.

PubMed

Centler, Florian; Heße, Falk; Thullner, Martin

2013-09-01

At field sites with varying redox conditions, different redox-specific microbial degradation pathways contribute to total contaminant degradation. The identification of pathway-specific contributions to total contaminant removal is of high practical relevance, yet difficult to achieve with current methods. Current stable-isotope-fractionation-based techniques focus on the identification of dominant biodegradation pathways under constant environmental conditions. We present an approach based on dual stable isotope data to estimate the individual contributions of two redox-specific pathways. We apply this approach to carbon and hydrogen isotope data obtained from reactive transport simulations of an organic contaminant plume in a two-dimensional aquifer cross section to test the applicability of the method. To take aspects typically encountered at field sites into account, additional simulations addressed the effects of transverse mixing, diffusion-induced stable-isotope fractionation, heterogeneities in the flow field, and mixing in sampling wells on isotope-based estimates for aerobic and anaerobic pathway contributions to total contaminant biodegradation. Results confirm the general applicability of the presented estimation method which is most accurate along the plume core and less accurate towards the fringe where flow paths receive contaminant mass and associated isotope signatures from the core by transverse dispersion. The presented method complements the stable-isotope-fractionation-based analysis toolbox. At field sites with varying redox conditions, it provides a means to identify the relative importance of individual, redox-specific degradation pathways. © 2013.

Using Proactivity, Time Discounting, and the Theory of Planned Behavior to Identify Predictors of Retirement Planning

ERIC Educational Resources Information Center

Griffin, Barbara; Loe, David; Hesketh, Beryl

2012-01-01

This study developed and tested a model to identify the predictors of retirement planning based on an extension of the theory of planned behavior ([TPB], Ajzen, 1991) that included individual differences in proactivity and time discounting. The results showed that personal attitudes, sense of control, social influence, and stable traits have a…

A multilevel latent growth modelling of the longitudinal changes in motivation regulations in physical education.

PubMed

Jaakkola, Timo; Wang, John; Yli-Piipari, Sami; Liukkonen, Jarmo

2015-03-01

The purpose of this study was to examine individual- and classroom-level differences in the longitudinal change in motivational regulations during physical education students' transition from elementary (Grade 6) across middle school (Grades 7 to 9). A sample of 757 Finnish adolescents (M = 12.71, SD = 0.23) participated in this study. Participants of the study responded to questionnaires collected six times. A multilevel latent growth modelling approach was used to analyze the data. Results showed that motivational regulations in physical education developed at different rates during middle school. More specifically, students': (a) identified regulation increased across Grades 6 to 9; (b) amotivation increased during middle school transition from Grade 6 to 7; and (c) introjected regulation declined from Grade 8 to 9. Other motivational regulations remained stable across time. The changes in amotivation and introjected regulation were largely due to individual factors, whereas the changes in identified regulation were due to environmental factors. Key pointsStudents' identified regulation increased across Grades 6 to 9.Students' amotivation increased across middle school transition from Grade 6 to 7.Students' introjected regulation declined from Grade 8 to 9.Other motivational regulations remained stable across time.

A Multilevel Latent Growth Modelling of the Longitudinal Changes in Motivation Regulations in Physical Education

PubMed Central

Jaakkola, Timo; Wang, John; Yli-Piipari, Sami; Liukkonen, Jarmo

2015-01-01

The purpose of this study was to examine individual- and classroom-level differences in the longitudinal change in motivational regulations during physical education students’ transition from elementary (Grade 6) across middle school (Grades 7 to 9). A sample of 757 Finnish adolescents (M = 12.71, SD = 0.23) participated in this study. Participants of the study responded to questionnaires collected six times. A multilevel latent growth modelling approach was used to analyze the data. Results showed that motivational regulations in physical education developed at different rates during middle school. More specifically, students’: (a) identified regulation increased across Grades 6 to 9; (b) amotivation increased during middle school transition from Grade 6 to 7; and (c) introjected regulation declined from Grade 8 to 9. Other motivational regulations remained stable across time. The changes in amotivation and introjected regulation were largely due to individual factors, whereas the changes in identified regulation were due to environmental factors. Key points Students’ identified regulation increased across Grades 6 to 9. Students’ amotivation increased across middle school transition from Grade 6 to 7. Students’ introjected regulation declined from Grade 8 to 9. Other motivational regulations remained stable across time. PMID:25729304

The chicken or the egg? Systematic investigation of the effect of order of administration of Memory Questionnaires and Well-being Scales.

PubMed

Philippe, Frederick L; Bouizegarene, Nabil; Guilbault, Valérie; Rajotte, Guillaume; Houle, Iliane

2015-01-01

Narrative research claims that episodic/autobiographical memory characteristics and themes represent stable individual differences that relate to well-being. However, the effects of the order of administration of memory descriptions and well-being scales have never been investigated. Of importance, social cognitive research has shown that trivial contextual factors, such as completing a self-report measure, can influence the type of memories recollected afterwards and that memory recollection can transiently affect subsequent self-report ratings--both of which underscore that transient contextual effects, rather than stable individual differences in memory could be responsible for the correlation between memory characteristics and well-being. The present study examined if the order in which (positive or negative) memory and well-being scales are completed affects the characteristics and themes of the memory described, the scores of well-being reported and the relationship between the two. The results revealed some effects of order of administration when memories were described before completing well-being scales, but only on a situational measure of well-being, not on a trait measure. In sum, we recommend assessing memory-related material at the end of questionnaires to avoid potential mood-priming effects.

Proinsulin is stable at room temperature for 24 hours in EDTA: A clinical laboratory analysis (adAPT 3).

PubMed

Davidson, Jane; McDonald, Timothy; Sutherland, Calum; Mostazir, Mohammod; VanAalten, Lidy; Wilkin, Terence

2017-01-01

Reference laboratories advise immediate separation and freezing of samples for the assay of proinsulin, which limit its practicability for smaller centres. Following the demonstration that insulin and C-peptide are stable in EDTA at room temperature for at least 24hours, we undertook simple stability studies to establish whether the same might apply to proinsulin. Venous blood samples were drawn from six adult women, some fasting, some not, aliquoted and assayed immediately and after storage at either 4°C or ambient temperature for periods from 2h to 24h. There was no significant variation or difference with storage time or storage condition in either individual or group analysis. Proinsulin appears to be stable at room temperature in EDTA for at least 24h. Immediate separation and storage on ice of samples for proinsulin assay is not necessary, which will simplify sample transport, particularly for multicentre trials.

Temporal dynamics of different cases of bi-stable figure-ground perception.

PubMed

Kogo, Naoki; Hermans, Lore; Stuer, David; van Ee, Raymond; Wagemans, Johan

2015-01-01

Segmentation of a visual scene in "figure" and "ground" is essential for perception of the three-dimensional layout of a scene. In cases of bi-stable perception, two distinct figure-ground interpretations alternate over time. We were interested in the temporal dynamics of these alternations, in particular when the same image is presented repeatedly, with short blank periods in-between. Surprisingly, we found that the intermittent presentation of Rubin's classical "face-or-vase" figure, which is frequently taken as a standard case of bi-stable figure-ground perception, often evoked perceptual switches during the short presentations and stabilization was not prominent. Interestingly, bi-stable perception of Kanizsa's anomalous transparency figure did strongly stabilize across blanks. We also found stabilization for the Necker cube, which we used for comparison. The degree of stabilization (and the lack of it) varied across stimuli and across individuals. Our results indicate, against common expectation, that the stabilization phenomenon cannot be generally evoked by intermittent presentation. We argue that top-down feedback factors such as familiarity, semantics, expectation, and perceptual bias contribute to the complex processes underlying the temporal dynamics of bi-stable figure-ground perception. Copyright © 2014 Elsevier Ltd. All rights reserved.

Novel Insights into DNA Methylation Features in Spermatozoa: Stability and Peculiarities

PubMed Central

Sayols, Sergi; Chianese, Chiara; Giachini, Claudia; Heyn, Holger; Esteller, Manel

2012-01-01

Data about the entire sperm DNA methylome are limited to two sperm donors whereas studies dealing with a greater number of subjects focused only on a few genes or were based on low resolution arrays. This implies that information about what we can consider as a normal sperm DNA methylome and whether it is stable among different normozoospermic individuals is still missing. The definition of the DNA methylation profile of normozoospermic men, the entity of inter-individual variability and the epigenetic characterization of quality-fractioned sperm subpopulations in the same subject (intra-individual variability) are relevant for a better understanding of pathological conditions. We addressed these questions by using the high resolution Infinium 450K methylation array and compared normal sperm DNA methylomes against somatic and cancer cells. Our study, based on the largest number of subjects (n = 8) ever considered for such a large number of CpGs (n = 487,517), provided clear evidence for i) a highly conserved DNA methylation profile among normozoospermic subjects; ii) a stable sperm DNA methylation pattern in different quality-fractioned sperm populations of the same individual. The latter finding is particularly relevant if we consider that different quality fractioned sperm subpopulations show differences in their structural features, metabolic and genomic profiles. We demonstrate, for the first time, that DNA methylation in normozoospermic men remains highly uniform regardless the quality of sperm subpopulations. In addition, our analysis provided both confirmatory and novel data concerning the sperm DNA methylome, including its peculiar features in respect to somatic and cancer cells. Our description about a highly polarized sperm DNA methylation profile, the clearly distinct genomic and functional organization of hypo- versus hypermethylated loci as well as the association of histone-enriched hypomethylated loci with embryonic development, which we now extended also to hypomethylated piRNAs-linked genes, provides solid basis for future basic and clinical research. PMID:23071498

Analysis of Lung Microbiota in Bronchoalveolar Lavage, Protected Brush and Sputum Samples from Subjects with Mild-To-Moderate Cystic Fibrosis Lung Disease

PubMed Central

Hogan, Deborah A.; Willger, Sven D.; Dolben, Emily L.; Hampton, Thomas H.; Stanton, Bruce A.; Morrison, Hilary G.; Sogin, Mitchell L.; Czum, Julianna; Ashare, Alix

2016-01-01

Individuals with cystic fibrosis (CF) often acquire chronic lung infections that lead to irreversible damage. We sought to examine regional variation in the microbial communities in the lungs of individuals with mild-to-moderate CF lung disease, to examine the relationship between the local microbiota and local damage, and to determine the relationships between microbiota in samples taken directly from the lung and the microbiota in spontaneously expectorated sputum. In this initial study, nine stable, adult CF patients with an FEV1>50% underwent regional sampling of different lobes of the right lung by bronchoalveolar lavage (BAL) and protected brush (PB) sampling of mucus plugs. Sputum samples were obtained from six of the nine subjects immediately prior to the procedure. Microbial community analysis was performed on DNA extracted from these samples and the extent of damage in each lobe was quantified from a recent CT scan. The extent of damage observed in regions of the right lung did not correlate with specific microbial genera, levels of community diversity or composition, or bacterial genome copies per ml of BAL fluid. In all subjects, BAL fluid from different regions of the lung contained similar microbial communities. In eight out of nine subjects, PB samples from different regions of the lung were also similar in microbial community composition, and were similar to microbial communities in BAL fluid from the same lobe. Microbial communities in PB samples were more diverse than those in BAL samples, suggesting enrichment of some taxa in mucus plugs. To our knowledge, this study is the first to examine the microbiota in different regions of the CF lung in clinically stable individuals with mild-to-moderate CF-related lung disease. PMID:26943329

Crevicular Fluid Biomarkers and Periodontal Disease Progression

PubMed Central

Oh, Min; Braun, Thomas M.; Ramseier, Christoph A.; Sugai, Jim V.; Giannobile, William V.

2014-01-01

Aim Assess the ability of a panel of gingival crevicular fluid (GCF) biomarkers as predictors of periodontal disease progression (PDP). Materials and Methods 100 individuals participated in a 12-month longitudinal investigation and categorized into 4 groups according to their periodontal status. GCF, clinical parameters, and saliva were collected bi-monthly. Sub-gingival plaque and serum were collected bi-annually. For 6 months, no periodontal treatment was provided. At 6-months, patients received periodontal therapy and continued participation from 6-12 months. GCF samples were analyzed by ELISA for MMP-8, MMP-9, OPG, CRP and IL-1β. Differences in median levels of GCF biomarkers were compared between stable and progressing participants using Wilcoxon Rank Sum test (p=0.05). Clustering algorithm was used to evaluate the ability of oral biomarkers to classify patients as either stable or progressing. Results Eighty-three individuals completed the 6-month monitoring phase. With the exception of GCF C-reactive protein, all biomarkers were significantly higher in the PDP group compared to stable patients. Clustering analysis showed highest sensitivity levels when biofilm pathogens and GCF biomarkers were combined with clinical measures, 74% (95% CI = 61,86). Conclusions Signature of GCF fluid-derived biomarkers combined with pathogens and clinical measures provides a sensitive measure for discrimination of PDP (ClinicalTrials.gov NCT00277745). PMID:24303954

Measuring sperm whales from their clicks: Stability of interpulse intervals and validation that they indicate whale length

NASA Astrophysics Data System (ADS)

Rhinelander, Marcus Q.; Dawson, Stephen M.

2004-04-01

Multiple pulses can often be distinguished in the clicks of sperm whales (Physeter macrocephalus). Norris and Harvey [in Animal Orientation and Navigation, NASA SP-262 (1972), pp. 397-417] proposed that this results from reflections within the head, and thus that interpulse interval (IPI) is an indicator of head length, and by extrapolation, total length. For this idea to hold, IPIs must be stable within individuals, but differ systematically among individuals of different size. IPI stability was examined in photographically identified individuals recorded repeatedly over different dives, days, and years. IPI variation among dives in a single day and days in a single year was statistically significant, although small in magnitude (it would change total length estimates by <3%). As expected, IPIs varied significantly among individuals. Most individuals showed significant increases in IPIs over several years, suggesting growth. Mean total lengths calculated from published IPI regressions were 13.1 to 16.1 m, longer than photogrammetric estimates of the same whales (12.3 to 15.3 m). These discrepancies probably arise from the paucity of large (12-16 m) whales in data used in published regressions. A new regression is offered for this size range.

The Magnitude of Trial-By-Trial Neural Variability Is Reproducible over Time and across Tasks in Humans.

PubMed

Arazi, Ayelet; Gonen-Yaacovi, Gil; Dinstein, Ilan

2017-01-01

Numerous studies have shown that neural activity in sensory cortices is remarkably variable over time and across trials even when subjects are presented with an identical repeating stimulus or task. This trial-by-trial neural variability is relatively large in the prestimulus period and considerably smaller (quenched) following stimulus presentation. Previous studies have suggested that the magnitude of neural variability affects behavior such that perceptual performance is better on trials and in individuals where variability quenching is larger. To what degree are neural variability magnitudes of individual subjects flexible or static? Here, we used EEG recordings from adult humans to demonstrate that neural variability magnitudes in visual cortex are remarkably consistent across different tasks and recording sessions. While magnitudes of neural variability differed dramatically across individual subjects, they were surprisingly stable across four tasks with different stimuli, temporal structures, and attentional/cognitive demands as well as across experimental sessions separated by one year. These experiments reveal that, in adults, neural variability magnitudes are mostly solidified individual characteristics that change little with task or time, and are likely to predispose individual subjects to exhibit distinct behavioral capabilities.

Neuroticism and locus of control as moderators of the relationships of charismatic and autocratic leadership with burnout.

PubMed

De Hoogh, Annebel H B; Den Hartog, Deanne N

2009-07-01

This study examined the moderating role of personality traits in the relationship between leader behavior and burnout. In two samples, employees (N = 91; N = 190) filled out the Maslach Burnout Inventory-General Survey and rated their leader's autocratic and charismatic leader behavior and their own neuroticism and internal work locus of control. As expected, neuroticism and internal work locus of control moderated the relationship between leader behavior and burnout. Charisma was associated with lower burnout, particularly for individuals low on internal locus. The relationship between autocratic leadership and burnout was positive for neurotic individuals, whereas for emotionally stable individuals this relationship weakened. These results were consistent across two independent samples: one with individual employee ratings of manager's leadership styles and the other with aggregate ratings of manager's leadership styles among employees in diverse organizations. Thus, although charismatic and autocratic leader behavior may respectively act to hinder or enhance overload and stress, the relationship between these leadership styles and burnout differs for followers with different traits.

The temporal stability and predictive validity of affect-based and cognition-based intentions.

PubMed

Keer, Mario; Conner, Mark; Van den Putte, Bas; Neijens, Peter

2014-06-01

Recent research has revealed individual differences in the extent to which people base their intentions on affect and cognition. Two studies are presented that assess whether such differences predict the strength of individuals' intention-behaviour relationships. Participants completed measures of affect, cognition, intention, and behaviour regarding a range of health behaviours. Study 1 (N = 300) found that the strength of the intention-behaviour relationship was significantly related to the extent to which individuals based their intentions on affect, but not to the extent they based them on cognition. Study 2 (N = 387) replicated the findings of the first study. In addition, Study 2 revealed that intention stability mediated the relationship between the degree people based their intentions on affect and the strength of the intention-behaviour relationship. Thus, individuals who base their intentions strongly on affect have more stable intentions, and are therefore more likely to enact them. © 2013 The British Psychological Society.

Determining origin in a migratory marine vertebrate: a novel method to integrate stable isotopes and satellite tracking

USGS Publications Warehouse

Vander Zanden, Hannah B.; Tucker, Anton D.; Hart, Kristen M.; Lamont, Margaret M.; Fujisaki, Ikuko; Addison, David S.; Mansfield, Katherine L.; Phillips, Katrina F.; Wunder, Michael B.; Bowen, Gabriel J.; Pajuelo, Mariela; Bolten, Alan B.; Bjorndal, Karen A.

2015-01-01

Stable isotope analysis is a useful tool to track animal movements in both terrestrial and marine environments. These intrinsic markers are assimilated through the diet and may exhibit spatial gradients as a result of biogeochemical processes at the base of the food web. In the marine environment, maps to predict the spatial distribution of stable isotopes are limited, and thus determining geographic origin has been reliant upon integrating satellite telemetry and stable isotope data. Migratory sea turtles regularly move between foraging and reproductive areas. Whereas most nesting populations can be easily accessed and regularly monitored, little is known about the demographic trends in foraging populations. The purpose of the present study was to examine migration patterns of loggerhead nesting aggregations in the Gulf of Mexico (GoM), where sea turtles have been historically understudied. Two methods of geographic assignment using stable isotope values in known-origin samples from satellite telemetry were compared: 1) a nominal approach through discriminant analysis and 2) a novel continuous-surface approach using bivariate carbon and nitrogen isoscapes (isotopic landscapes) developed for this study. Tissue samples for stable isotope analysis were obtained from 60 satellite-tracked individuals at five nesting beaches within the GoM. Both methodological approaches for assignment resulted in high accuracy of foraging area determination, though each has advantages and disadvantages. The nominal approach is more appropriate when defined boundaries are necessary, but up to 42% of the individuals could not be considered in this approach. All individuals can be included in the continuous-surface approach, and individual results can be aggregated to identify geographic hotspots of foraging area use, though the accuracy rate was lower than nominal assignment. The methodological validation provides a foundation for future sea turtle studies in the region to inexpensively determine geographic origin for large numbers of untracked individuals. Regular monitoring of sea turtle nesting aggregations with stable isotope sampling can be used to fill critical data gaps regarding habitat use and migration patterns. Probabilistic assignment to origin with isoscapes has not been previously used in the marine environment, but the methods presented here could also be applied to other migratory marine species.

Determining origin in a migratory marine vertebrate: a novel method to integrate stable isotopes and satellite tracking.

PubMed

Zanden, Hannah B Vander; Tucker, Anton D; Hart, Kristen M; Lamont, Margaret M; Fuisaki, Ikuko; Addison, David; Mansfield, Katherine L; Phillips, Katrina F; Wunder, Michael B; Bowen, Gabriel J; Pajuelo, Mariela; Bolten, Alan B; Bjorndal, Karen A

2015-03-01

Stable isotope analysis is a useful tool to track animal movements in both terrestrial and marine environments. These intrinsic markers are assimilated through the diet and may exhibit spatial gradients as a result of biogeochemical processes at the base of the food web. In the marine environment, maps to predict the spatial distribution of stable isotopes are limited, and thus determining geographic origin has been reliant upon integrating satellite telemetry and stable isotope data. Migratory sea turtles regularly move between foraging and reproductive areas. Whereas most nesting populations can be easily accessed and regularly monitored, little is known about the demographic trends in foraging populations. The purpose of the present study was to examine migration patterns of loggerhead nesting aggregations in the Gulf of Mexico (GoM), where sea turtles have been historically understudied. Two methods of geographic assignment using stable isotope values in known-origin samples from satellite telemetry were compared: (1) a nominal approach through discriminant analysis and (2) a novel continuous-surface approach using bivariate carbon and nitrogen isoscapes (isotopic landscapes) developed for this study. Tissue samples for stable isotope analysis were obtained from 60 satellite-tracked individuals at five nesting beaches within the GoM. Both methodological approaches for assignment resulted in high accuracy of foraging area determination, though each has advantages and disadvantages. The nominal approach is more appropriate when defined boundaries are necessary, but up to 42% of the individuals could not be considered in this approach. All individuals can be included in the continuous-surface approach, and individual results can be aggregated to identify geographic hotspots of foraging area use, though the accuracy rate was lower than nominal assignment. The methodological validation provides a foundation for future sea turtle studies in the region to inexpensively determine geographic origin for large numbers of untracked individuals. Regular monitoring of sea turtle nesting aggregations with stable isotope sampling can be used to fill critical data gaps regarding habitat use and migration patterns. Probabilistic assignment to origin with isoscapes has not been previously used in the marine environment, but the methods presented here could also be applied to other migratory marine species.

Who Sees Human? The Stability and Importance of Individual Differences in Anthropomorphism

PubMed Central

Waytz, Adam; Cacioppo, John; Epley, Nicholas

2014-01-01

Anthropomorphism is a far-reaching phenomenon that incorporates ideas from social psychology, cognitive psychology, developmental psychology, and the neurosciences. Although commonly considered to be a relatively universal phenomenon with only limited importance in modern industrialized societies—more cute than critical—our research suggests precisely the opposite. In particular, we provide a measure of stable individual differences in anthropomorphism that predicts three important consequences for everyday life. This research demonstrates that individual differences in anthropomorphism predict the degree of moral care and concern afforded to an agent, the amount of responsibility and trust placed on an agent, and the extent to which an agent serves as a source of social influence on the self. These consequences have implications for disciplines outside of psychology including human–computer interaction, business (marketing and finance), and law. Concluding discussion addresses how understanding anthropomorphism not only informs the burgeoning study of nonpersons, but how it informs classic issues underlying person perception as well. PMID:24839457

ANIMAL BEHAVIOR AND WELL-BEING SYMPOSIUM: Interaction between coping style/personality, stress, and welfare: Relevance for domestic farm animals.

PubMed

Koolhaas, J M; Van Reenen, C G

2016-06-01

This paper will argue that understanding animal welfare and the individual vulnerability to stress-related disease requires a fundamental understanding of functional individual variation as it occurs in nature as well as the underlying neurobiology and neuroendocrinology. Ecological studies in feral populations of mice, fish, and birds start to recognize the functional significance of phenotypes that individually differ in their behavioral and neuroendocrine response to environmental challenge. Recent studies indicate that the individual variation within a species may buffer the species for strong fluctuations in the natural habitat. Similarly, evolutionary ancient behavioral trait characteristics have now been identified in a range of domestic farm animals including cattle, pigs, and horses. Individual variation in behavior can be summarized in a 3-dimensional model with coping style, emotionality, and sociality as independent dimensions. These dimensions can be considered trait characteristics that are stable over time and across situations within the individual. This conceptual model has several consequences. First, the coping style dimension is strongly associated with differential stress vulnerability. Social stress studies show that proactive individuals are resilient under stable environmental conditions but vulnerable when outcome expectancies are violated. Reactive individuals are, in fact, rather flexible and seem to adapt more easily to a changing environment. A second consequence relates to genetics and breeding. Genetic selection for one trait usually implies selection for other traits as well. It is discussed that a more balanced breeding program that takes into account biologically functional temperamental traits will lead to more robust domestic farm animals. Finally, the relationship between temperamental traits, animal production, fitness, and welfare is discussed.

HIV-1 infections with multiple founders are associated with higher viral loads than infections with single founders.

PubMed

Janes, Holly; Herbeck, Joshua T; Tovanabutra, Sodsai; Thomas, Rasmi; Frahm, Nicole; Duerr, Ann; Hural, John; Corey, Lawrence; Self, Steve G; Buchbinder, Susan P; McElrath, M Juliana; O'Connell, Robert J; Paris, Robert M; Rerks-Ngarm, Supachai; Nitayaphan, Sorachai; Pitisuttihum, Punnee; Kaewkungwal, Jaranit; Robb, Merlin L; Michael, Nelson L; Mullins, James I; Kim, Jerome H; Gilbert, Peter B; Rolland, Morgane

2015-10-01

Given the variation in the HIV-1 viral load (VL) set point across subjects, as opposed to a fairly stable VL over time within an infected individual, it is important to identify the characteristics of the host and virus that affect VL set point. Although recently infected individuals with multiple phylogenetically linked HIV-1 founder variants represent a minority of HIV-1 infections, we found--n two different cohorts--hat more diverse HIV-1 populations in early infection were associated with significantly higher VL 1 year after HIV-1 diagnosis.

"Coming out" in the age of social constructionism.

PubMed

Rust, P C

1997-01-01

Abstract This article examines sexual identity formation among 346 lesbian-identified and 60 bisexual-identified women. On average, bisexuals come out at later ages and exhibit less "stable" identity histories. However, variations in identity history among lesbians and bisexuals overshadow the differences between them and demonstrate that coming out is not a linear, goal-oriented, developmental process. Sexual identity formation must be reconceptualized as a process of describing one's social location within a changing social context. Changes in sexual identity are, therefore, expected of mature individuals as they maintain an accurate description of their position vis-à-vis other individuals, groups, and institutions.

Spatial and temporal variance in fatty acid and stable isotope signatures across trophic levels in large river systems

USGS Publications Warehouse

Fritts, Andrea; Knights, Brent C.; Lafrancois, Toben D.; Bartsch, Lynn; Vallazza, Jon; Bartsch, Michelle; Richardson, William B.; Karns, Byron N.; Bailey, Sean; Kreiling, Rebecca

2018-01-01

Fatty acid and stable isotope signatures allow researchers to better understand food webs, food sources, and trophic relationships. Research in marine and lentic systems has indicated that the variance of these biomarkers can exhibit substantial differences across spatial and temporal scales, but this type of analysis has not been completed for large river systems. Our objectives were to evaluate variance structures for fatty acids and stable isotopes (i.e. δ13C and δ15N) of seston, threeridge mussels, hydropsychid caddisflies, gizzard shad, and bluegill across spatial scales (10s-100s km) in large rivers of the Upper Mississippi River Basin, USA that were sampled annually for two years, and to evaluate the implications of this variance on the design and interpretation of trophic studies. The highest variance for both isotopes was present at the largest spatial scale for all taxa (except seston δ15N) indicating that these isotopic signatures are responding to factors at a larger geographic level rather than being influenced by local-scale alterations. Conversely, the highest variance for fatty acids was present at the smallest spatial scale (i.e. among individuals) for all taxa except caddisflies, indicating that the physiological and metabolic processes that influence fatty acid profiles can differ substantially between individuals at a given site. Our results highlight the need to consider the spatial partitioning of variance during sample design and analysis, as some taxa may not be suitable to assess ecological questions at larger spatial scales.

Relationships between water and paddlefish Polyodon spathula dentary elemental and stable-isotopic signatures: potential application for reconstructing environmental history

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

Bock, Lindsey R.; Whitledge, Gregory W.; Pracheil, Brenda M.

The objectives of this study were to characterize relationships between water and paddlefish Polyodon spathula dentary Sr:Ca, δ 18O and stable hydrogen isotope ratio (δD) to determine the accuracy with which individual P. spathula could be assigned to their collection locations using dentary-edge Sr:Ca, δD and δ 18O. A laboratory experiment was also conducted to determine whether dentary Sr:Ca in age 0 year P. spathula would reflect shifts in water Sr:Ca to which fish were exposed. Significant linear relationships between water and dentary Sr:Ca, δD and δ 18O were observed, although the relationship between water and dentary δ 18O wasmore » weaker than those for Sr:Ca and δD. Classification success for individual fish to collection locations that differed in water Sr:Ca, δD and δ 18O ranged from 86 to 100% based on dentary-edge Sr:Ca, δD and δ18O. Dentary Sr:Ca increased significantly in laboratory-reared age 0 year P. spathula following 4 weeks of exposure to elevated water Sr:Ca; dentary Sr:Ca of fish held in water with elevated Sr:Ca was also significantly higher than that of control fish reared in ambient laboratory water. Results indicated that P. spathula dentaries reflect water signatures for commonly-applied natural chemical markers and strongly suggest that dentary microchemistry and stable-isotopic compositions will be applicable for reconstructing P. spathula environmental history in locations where sufficient spatial differences in water chemistry occur.« less

Ankle instability effects on joint position sense when stepping across the active movement extent discrimination apparatus.

PubMed

Witchalls, Jeremy; Waddington, Gordon; Blanch, Peter; Adams, Roger

2012-01-01

Individuals with and without functional ankle instability have been tested for deficits in lower limb proprioception with varied results. To determine whether a new protocol for testing participants' joint position sense during stepping is reliable and can detect differences between participants with unstable and stable ankles. Descriptive laboratory study. University clinical laboratory. Sample of convenience involving 21 young adult university students and staff. Ankle stability was categorized by score on the Cumberland Ankle Instability Tool; 13 had functional ankle instability, 8 had healthy ankles. Test-retest of ankle joint position sense when stepping onto and across the Active Movement Extent Discrimination Apparatus twice, separated by an interim test, standing still on the apparatus and moving only 1 ankle into inversion. Difference in scores between groups with stable and unstable ankles and between test repeats. Participants with unstable ankles were worse at differentiating between inversion angles underfoot in both testing protocols. On repeated testing with the stepping protocol, performance of the group with unstable ankles was improved (Cohen d = 1.06, P = .006), whereas scores in the stable ankle group did not change in the second test (Cohen d = 0.04, P = .899). Despite this improvement, the unstable group remained worse at differentiating inversion angles on the stepping retest (Cohen d = 0.99, P = .020). The deficits on proprioceptive tests shown by individuals with functional ankle instability improved with repeated exposure to the test situation. The learning effect may be the result of systematic exposure to ankle-angle variation that led to movement-specific learning or increased confidence when stepping across the apparatus.

Relationships between water and paddlefish Polyodon spathula dentary elemental and stable-isotopic signatures: potential application for reconstructing environmental history

DOE PAGES

Bock, Lindsey R.; Whitledge, Gregory W.; Pracheil, Brenda M.; ...

2016-07-26

The objectives of this study were to characterize relationships between water and paddlefish Polyodon spathula dentary Sr:Ca, δ 18O and stable hydrogen isotope ratio (δD) to determine the accuracy with which individual P. spathula could be assigned to their collection locations using dentary-edge Sr:Ca, δD and δ 18O. A laboratory experiment was also conducted to determine whether dentary Sr:Ca in age 0 year P. spathula would reflect shifts in water Sr:Ca to which fish were exposed. Significant linear relationships between water and dentary Sr:Ca, δD and δ 18O were observed, although the relationship between water and dentary δ 18O wasmore » weaker than those for Sr:Ca and δD. Classification success for individual fish to collection locations that differed in water Sr:Ca, δD and δ 18O ranged from 86 to 100% based on dentary-edge Sr:Ca, δD and δ18O. Dentary Sr:Ca increased significantly in laboratory-reared age 0 year P. spathula following 4 weeks of exposure to elevated water Sr:Ca; dentary Sr:Ca of fish held in water with elevated Sr:Ca was also significantly higher than that of control fish reared in ambient laboratory water. Results indicated that P. spathula dentaries reflect water signatures for commonly-applied natural chemical markers and strongly suggest that dentary microchemistry and stable-isotopic compositions will be applicable for reconstructing P. spathula environmental history in locations where sufficient spatial differences in water chemistry occur.« less

Stoichiometric Control of Multiple Different Tectons in Coordination-Driven Self-assembly

PubMed Central

Lee, Junseong; Ghosh, Koushik; Stang, Peter J.

2009-01-01

We present a general strategy for the synthesis of stable, multi-component fused polygon complexes where coordination-driven self-assembly allows for single supramolecular species can be formed from multi-component self-assembly and the shape of the obtained polygons can be controlled by simply changing the ratio of individual components. The compounds are characterized by Multinuclear NMR, ESI Mass spectrometry. PMID:19663439

Self-Esteem Is Relatively Stable Late in Life: The Role of Resources in the Health, Self-Regulation, and Social Domains

ERIC Educational Resources Information Center

Wagner, Jenny; Hoppmann, Christiane; Ram, Nilam; Gerstorf, Denis

2015-01-01

A large body of research has documented changes in self-esteem across adulthood and individual-difference correlates thereof. However, little is known about whether people maintain their self-esteem until the end of life and what role key risk factors in the health, cognitive, self-regulatory, and social domains play. To examine these questions,…

Consistency in boldness, activity and exploration at different stages of life

PubMed Central

2013-01-01

Background Animals show consistent individual behavioural patterns over time and over situations. This phenomenon has been referred to as animal personality or behavioural syndromes. Little is known about consistency of animal personalities over entire life times. We investigated the repeatability of behaviour in common voles (Microtus arvalis) at different life stages, with different time intervals, and in different situations. Animals were tested using four behavioural tests in three experimental groups: 1. before and after maturation over three months, 2. twice as adults during one week, and 3. twice as adult animals over three months, which resembles a substantial part of their entire adult life span of several months. Results Different behaviours were correlated within and between tests and a cluster analysis showed three possible behavioural syndrome-axes, which we name boldness, exploration and activity. Activity and exploration behaviour in all tests was highly repeatable in adult animals tested over one week. In animals tested over maturation, exploration behaviour was consistent whereas activity was not. Voles that were tested as adults with a three-month interval showed the opposite pattern with stable activity but unstable exploration behaviour. Conclusions The consistency in behaviour over time suggests that common voles do express stable personality over short time. Over longer periods however, behaviour is more flexible and depending on life stage (i.e. tested before/after maturation or as adults) of the tested individual. Level of boldness or activity does not differ between tested groups and maintenance of variation in behavioural traits can therefore not be explained by expected future assets as reported in other studies. PMID:24314274

Consistency in boldness, activity and exploration at different stages of life.

PubMed

Herde, Antje; Eccard, Jana A

2013-12-07

Animals show consistent individual behavioural patterns over time and over situations. This phenomenon has been referred to as animal personality or behavioural syndromes. Little is known about consistency of animal personalities over entire life times. We investigated the repeatability of behaviour in common voles (Microtus arvalis) at different life stages, with different time intervals, and in different situations. Animals were tested using four behavioural tests in three experimental groups: 1. before and after maturation over three months, 2. twice as adults during one week, and 3. twice as adult animals over three months, which resembles a substantial part of their entire adult life span of several months. Different behaviours were correlated within and between tests and a cluster analysis showed three possible behavioural syndrome-axes, which we name boldness, exploration and activity. Activity and exploration behaviour in all tests was highly repeatable in adult animals tested over one week. In animals tested over maturation, exploration behaviour was consistent whereas activity was not. Voles that were tested as adults with a three-month interval showed the opposite pattern with stable activity but unstable exploration behaviour. The consistency in behaviour over time suggests that common voles do express stable personality over short time. Over longer periods however, behaviour is more flexible and depending on life stage (i.e. tested before/after maturation or as adults) of the tested individual. Level of boldness or activity does not differ between tested groups and maintenance of variation in behavioural traits can therefore not be explained by expected future assets as reported in other studies.

Seasonal variation in the free-running period in two Talitrus saltator populations from Italian beaches differing in morphodynamics and human disturbance

NASA Astrophysics Data System (ADS)

Nardi, M.; Morgan, E.; Scapini, F.

2003-10-01

The sandhopper Talitrus saltator Montagu (Amphipoda) is a widespread species adapted to different changing environmental conditions and which typically shows a clear circadian rhythm of locomotor activity. The populations from two beaches on the western Italian coast differing in coastline dynamics (eroded versus dynamically stable) and human disturbance (inside a natural park versus freely used and cleaned for leisure) were studied to highlight intrapopulation variation in the endogenous locomotor rhythm. The activity of adult sandhoppers was studied under constant laboratory conditions within individual recording chambers. Variation of the free-running period was analysed at individual level within each population. Greater variability was found than previously reported for the circadian rhythm period of T. saltator, and seasonal variation was shown for the first time. Differences in the level of variation were correlated with coastline dynamics.

Comparing Multiple Criteria for Species Identification in Two Recently Diverged Seabirds

PubMed Central

Militão, Teresa; Gómez-Díaz, Elena; Kaliontzopoulou, Antigoni; González-Solís, Jacob

2014-01-01

Correct species identification is a crucial issue in systematics with key implications for prioritising conservation effort. However, it can be particularly challenging in recently diverged species due to their strong similarity and relatedness. In such cases, species identification requires multiple and integrative approaches. In this study we used multiple criteria, namely plumage colouration, biometric measurements, geometric morphometrics, stable isotopes analysis (SIA) and genetics (mtDNA), to identify the species of 107 bycatch birds from two closely related seabird species, the Balearic (Puffinus mauretanicus) and Yelkouan (P. yelkouan) shearwaters. Biometric measurements, stable isotopes and genetic data produced two stable clusters of bycatch birds matching the two study species, as indicated by reference birds of known origin. Geometric morphometrics was excluded as a species identification criterion since the two clusters were not stable. The combination of plumage colouration, linear biometrics, stable isotope and genetic criteria was crucial to infer the species of 103 of the bycatch specimens. In the present study, particularly SIA emerged as a powerful criterion for species identification, but temporal stability of the isotopic values is critical for this purpose. Indeed, we found some variability in stable isotope values over the years within each species, but species differences explained most of the variance in the isotopic data. Yet this result pinpoints the importance of examining sources of variability in the isotopic data in a case-by-case basis prior to the cross-application of the SIA approach to other species. Our findings illustrate how the integration of several methodological approaches can help to correctly identify individuals from recently diverged species, as each criterion measures different biological phenomena and species divergence is not expressed simultaneously in all biological traits. PMID:25541978

24-Hour protein, arginine and citrulline metabolism in fed critically ill children - A stable isotope tracer study.

PubMed

de Betue, Carlijn T I; Garcia Casal, Xiomara C; van Waardenburg, Dick A; Schexnayder, Stephen M; Joosten, Koen F M; Deutz, Nicolaas E P; Engelen, Marielle P K J

2017-06-01

The reference method to study protein and arginine metabolism in critically ill children is measuring plasma amino acid appearances with stable isotopes during a short (4-8 h) time period and extrapolate results to 24-h. However, 24-h measurements may be variable due to critical illness related factors and a circadian rhythm could be present. Since only short duration stable isotope studies in critically ill children have been conducted before, the aim of this study was to investigate 24-h appearance of specific amino acids representing protein and arginine metabolism, with stable isotope techniques in continuously fed critically ill children. In eight critically ill children, admitted to the pediatric (n = 4) or cardiovascular (n = 4) intensive care unit, aged 0-10 years, receiving continuous (par)enteral nutrition with protein intake 1.0-3.7 g/kg/day, a 24-h stable isotope tracer protocol was carried out. L-[ring- 2 H 5 ]-phenylalanine, L-[3,3- 2 H 2 ]-tyrosine, L-[5,5,5- 2 H 3 ]-leucine, L-[guanido- 15 N 2 ]-arginine and L-[5- 13 C-3,3,4,4- 2 H 4 ]-citrulline were infused intravenously and L-[ 15 N]-phenylalanine and L-[1- 13 C]leucine enterally. Arterial blood was sampled every hour. Coefficients of variation, representing intra-individual variability, of the amino acid appearances of phenylalanine, tyrosine, leucine, arginine and citrulline were high, on average 14-19% for intravenous tracers and 23-26% for enteral tracers. No evident circadian rhythm was present. The pattern and overall 24-h level of whole body protein balance differed per individual. In continuously fed stable critically ill children, the amino acid appearances of phenylalanine, tyrosine, leucine, arginine and citrulline show high variability. This should be kept in mind when performing stable isotope studies in this population. There was no apparent circadian rhythm. NCT01511354 on clinicaltrials.gov. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Flying Drosophilamelanogaster maintain arbitrary but stable headings relative to the angle of polarized light.

PubMed

Warren, Timothy L; Weir, Peter T; Dickinson, Michael H

2018-05-11

Animals must use external cues to maintain a straight course over long distances. In this study, we investigated how the fruit fly Drosophila melanogaster selects and maintains a flight heading relative to the axis of linearly polarized light, a visual cue produced by the atmospheric scattering of sunlight. To track flies' headings over extended periods, we used a flight simulator that coupled the angular velocity of dorsally presented polarized light to the stroke amplitude difference of the animals' wings. In the simulator, most flies actively maintained a stable heading relative to the axis of polarized light for the duration of 15 min flights. We found that individuals selected arbitrary, unpredictable headings relative to the polarization axis, which demonstrates that D . melanogaster can perform proportional navigation using a polarized light pattern. When flies flew in two consecutive bouts separated by a 5 min gap, the two flight headings were correlated, suggesting individuals retain a memory of their chosen heading. We found that adding a polarized light pattern to a light intensity gradient enhanced flies' orientation ability, suggesting D . melanogaster use a combination of cues to navigate. For both polarized light and intensity cues, flies' capacity to maintain a stable heading gradually increased over several minutes from the onset of flight. Our findings are consistent with a model in which each individual initially orients haphazardly but then settles on a heading which is maintained via a self-reinforcing process. This may be a general dispersal strategy for animals with no target destination. © 2018. Published by The Company of Biologists Ltd.

Electromyographic amplitude variability of chewing cycles in deaf individuals.

PubMed

de Oliveira, A Siriani; Vitti, M; Chaves, T C; Bevilaqua-Grossi, D; Zuccolotto, M C C; Regalo, S C H

2006-09-01

This study had the goal of determining if the amplitude of the surface electromyograph signals changes in terms of time of analysis and subjects, deaf or normal listeners, when estimated in a 250 ms of length window, visually determined, considering the most stable signal period from the center of the chewing cycle. In order to do this, groups with control subjects, listeners and deaf individuals, who made use of the Brazilian sign language (LIBRAS), were studied. All participants performed continuous 5 s of chewing for the electromyographic recording of the temporalis and masseter muscles. The normalized RMS values of three chewing cycles were compared between and among groups. The results from the Kruskall-Wallis test did not show any statistically significant differences (p > 0.05) between the normalized RMS values obtained in the three individual chewing cycles, for each of the two completed and evaluated cycles, in both groups studied. The Mann-Whitney test showed that the mean normalized RMS values obtained in the first chewing cycle were higher for the control group when compared to the mean amplitude values of the first chewing cycle of the group of deaf volunteers. It can be concluded that, in these experimental conditions, the RMS values obtained from the select windows of 250 ms length duration, in relatively stable periods of the electromyographic signal of chewing cycles did not suffer any changes in terms of EMG register duration, in both studied groups, but does give evidence of the differences among the groups.

Outcomes of childhood conduct problem trajectories in early adulthood: findings from the ALSPAC study.

PubMed

Kretschmer, Tina; Hickman, Matthew; Doerner, Rita; Emond, Alan; Lewis, Glyn; Macleod, John; Maughan, Barbara; Munafò, Marcus R; Heron, Jon

2014-07-01

Although conduct problems in childhood are stably associated with problem outcomes, not every child who presents with conduct problems is at risk. This study extends previous studies by testing whether childhood conduct problem trajectories are predictive of a wide range of other health and behavior problems in early adulthood using a general population sample. Based on 7,218 individuals from the Avon longitudinal study of parents and children, a three-step approach was used to model childhood conduct problem development and identify differences in early adult health and behavior problems. Childhood conduct problems were assessed on six occasions between age 4 and 13 and health and behavior outcomes were measured at age 18. Individuals who displayed early-onset persistent conduct problems throughout childhood were at greater risk for almost all forms of later problems. Individuals on the adolescent-onset conduct problem path consumed more tobacco and illegal drugs and engaged more often in risky sexual behavior than individuals without childhood conduct problems. Levels of health and behavior problems for individuals on the childhood-limited path were in between those for stable low and stable high trajectories. Childhood conduct problems are pervasive and substantially affect adjustment in early adulthood both in at-risk samples as shown in previous studies, but also in a general population sample. Knowing a child's developmental course can help to evaluate the risk for later maladjustment and be indicative of the need for early intervention.

Fear of predation drives stable and differentiated social relationships in guppies

PubMed Central

Heathcote, Robert J. P.; Darden, Safi K.; Franks, Daniel W.; Ramnarine, Indar W.; Croft, Darren P.

2017-01-01

Social relationships can have important consequences for fitness in animals. Whilst numerous studies have shown that individuals often join larger groups in response to perceived predation risk (i.e. fear of predation), the importance of predation risk in driving the formation and stability of social relationships within groups has been relatively ignored. We experimentally tested how predation threat influenced fine-scale social network structure using Trinidadian guppies (Poecilia reticulata). When perceived predation risk was high, individuals developed stable and more differentiated social ties compared to when perceived risk was low. Intriguingly, social differentiation coincided with shoals being somewhat smaller under high-perceived risk, suggesting a possible conflict between forming stable social relationships and larger social groups. Individuals most at risk of predation (large and bold individuals) showed the most exaggerated responses in several social measures. Taken together, we provide the first experimental evidence that proximate risk of predation can increase the intensity of social relationships and fine-scale social structure in animal populations. PMID:28150706

Fear of predation drives stable and differentiated social relationships in guppies.

PubMed

Heathcote, Robert J P; Darden, Safi K; Franks, Daniel W; Ramnarine, Indar W; Croft, Darren P

2017-02-02

Social relationships can have important consequences for fitness in animals. Whilst numerous studies have shown that individuals often join larger groups in response to perceived predation risk (i.e. fear of predation), the importance of predation risk in driving the formation and stability of social relationships within groups has been relatively ignored. We experimentally tested how predation threat influenced fine-scale social network structure using Trinidadian guppies (Poecilia reticulata). When perceived predation risk was high, individuals developed stable and more differentiated social ties compared to when perceived risk was low. Intriguingly, social differentiation coincided with shoals being somewhat smaller under high-perceived risk, suggesting a possible conflict between forming stable social relationships and larger social groups. Individuals most at risk of predation (large and bold individuals) showed the most exaggerated responses in several social measures. Taken together, we provide the first experimental evidence that proximate risk of predation can increase the intensity of social relationships and fine-scale social structure in animal populations.

Longitudinal Effects on Early Adolescent Language: A Twin Study

PubMed Central

DeThorne, Laura Segebart; Smith, Jamie Mahurin; Betancourt, Mariana Aparicio; Petrill, Stephen A.

2016-01-01

Purpose We evaluated genetic and environmental contributions to individual differences in language skills during early adolescence, measured by both language sampling and standardized tests, and examined the extent to which these genetic and environmental effects are stable across time. Method We used structural equation modeling on latent factors to estimate additive genetic, shared environmental, and nonshared environmental effects on variance in standardized language skills (i.e., Formal Language) and productive language-sample measures (i.e., Productive Language) in a sample of 527 twins across 3 time points (mean ages 10–12 years). Results Individual differences in the Formal Language factor were influenced primarily by genetic factors at each age, whereas individual differences in the Productive Language factor were primarily due to nonshared environmental influences. For the Formal Language factor, the stability of genetic effects was high across all 3 time points. For the Productive Language factor, nonshared environmental effects showed low but statistically significant stability across adjacent time points. Conclusions The etiology of language outcomes may differ substantially depending on assessment context. In addition, the potential mechanisms for nonshared environmental influences on language development warrant further investigation. PMID:27732720

Body Schema Illusions: A Study of the Link between the Rubber Hand and Kinesthetic Mirror Illusions through Individual Differences

PubMed Central

Metral, Morgane; Gonthier, Corentin; Luyat, Marion

2017-01-01

Background The well-known rubber hand paradigm induces an illusion by having participants feel the touch applied to a fake hand. In parallel, the kinesthetic mirror illusion elicits illusions of movement by moving the reflection of a participant's arm. Experimental manipulation of sensory inputs leads to emergence of these multisensory illusions. There are strong conceptual similarities between these two illusions, suggesting that they rely on the same neurophysiological mechanisms, but this relationship has never been investigated. Studies indicate that participants differ in their sensitivity to these illusions, which provides a possibility for studying the relationship between these two illusions. Method We tested 36 healthy participants to confirm that there exist reliable individual differences in sensitivity to the two illusions and that participants sensitive to one illusion are also sensitive to the other. Results The results revealed that illusion sensitivity was very stable across trials and that individual differences in sensitivity to the kinesthetic mirror illusion were highly related to individual differences in sensitivity to the rubber hand illusion. Conclusions Overall, these results support the idea that these two illusions may be both linked to a transitory modification of body schema, wherein the most sensitive people have the most malleable body schema. PMID:29201910

Body Schema Illusions: A Study of the Link between the Rubber Hand and Kinesthetic Mirror Illusions through Individual Differences.

PubMed

Metral, Morgane; Gonthier, Corentin; Luyat, Marion; Guerraz, Michel

2017-01-01

The well-known rubber hand paradigm induces an illusion by having participants feel the touch applied to a fake hand. In parallel, the kinesthetic mirror illusion elicits illusions of movement by moving the reflection of a participant's arm. Experimental manipulation of sensory inputs leads to emergence of these multisensory illusions. There are strong conceptual similarities between these two illusions, suggesting that they rely on the same neurophysiological mechanisms, but this relationship has never been investigated. Studies indicate that participants differ in their sensitivity to these illusions, which provides a possibility for studying the relationship between these two illusions. We tested 36 healthy participants to confirm that there exist reliable individual differences in sensitivity to the two illusions and that participants sensitive to one illusion are also sensitive to the other. The results revealed that illusion sensitivity was very stable across trials and that individual differences in sensitivity to the kinesthetic mirror illusion were highly related to individual differences in sensitivity to the rubber hand illusion. Overall, these results support the idea that these two illusions may be both linked to a transitory modification of body schema, wherein the most sensitive people have the most malleable body schema.

Litter type control on soil C and N stabilization dynamics in a temperate forest.

PubMed

Hatton, Pierre-Joseph; Castanha, Cristina; Torn, Margaret S; Bird, Jeffrey A

2015-03-01

While plant litters are the main source of soil organic matter (SOM) in forests, the controllers and pathways to stable SOM formation remain unclear. Here, we address how litter type ((13) C/(15) N-labeled needles vs. fine roots) and placement-depth (O vs. A horizon) affect in situ C and N dynamics in a temperate forest soil after 5 years. Litter type rather than placement-depth controlled soil C and N retention after 5 years in situ, with belowground fine root inputs greatly enhancing soil C (x1.4) and N (x1.2) retention compared with aboveground needles. While the proportions of added needle and fine root-derived C and N recovered into stable SOM fractions were similar, they followed different transformation pathways into stable SOM fractions: fine root transfer was slower than for needles, but proportionally more of the remaining needle-derived C and N was transferred into stable SOM fractions. The stoichiometry of litter-derived C vs. N within individual SOM fractions revealed the presence at least two pools of different turnover times (per SOM fraction) and emphasized the role of N-rich compounds for long-term persistence. Finally, a regression approach suggested that models may underestimate soil C retention from litter with fast decomposition rates. © 2014 John Wiley & Sons Ltd.

Hawks, doves, and mixed-symmetry games.

PubMed

Crowley, P H

2000-06-21

The hawk-dove game has proved to be an important tool for understanding the role of aggression in social interactions. Here, the game is presented in a more general form (GHD) to facilitate analyses of interactions between individuals that may differ in "size", where size is interpreted as a surrogate for resource holding power. Three different situations are considered, based on the availability and use of information that interacting individuals have about their sizes: the classical symmetric case, in which no information about sizes is used, the asymmetric case, in which the individuals know their relative sizes and thus their chances of prevailing in combat, and a mixed-symmetry case, in which each individual only knows its own size (or only knows its opponent's size). I describe and use some recently developed methods for multitype games-evolutionary games involving two or more categories of players. With these methods and others, the evolutionarily stable strategies (ESSs) that emerge for the three different cases are identified and compared. A proof of the form and uniqueness of the ESS for the mixed-symmetry case is presented. In this situation, one size category at most can play a mixed strategy; larger individuals are aggressive and smaller individuals are not. As the number of size categories approaches infinity and the size distribution becomes continuous, there is a threshold size, above which all individuals are aggressive, and below which they are not. Copyright 2000 Academic Press.

Cognitive Abilities, Monitoring Confidence, and Control Thresholds Explain Individual Differences in Heuristics and Biases

PubMed Central

Jackson, Simon A.; Kleitman, Sabina; Howie, Pauline; Stankov, Lazar

2016-01-01

In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence, and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgments, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing that lower monitoring confidence and higher control thresholds promote error checking. Participants (N = 250) completed tasks assessing their fluid reasoning abilities, stable monitoring confidence levels, and the control threshold they impose on their decisions. They also completed seven typical heuristic and biases tasks such as the cognitive reflection test and Resistance to Framing. Using structural equation modeling, we found that individuals with higher reasoning abilities, lower monitoring confidence, and higher control threshold performed significantly and, at times, substantially better on the heuristic and biases tasks. Individuals with higher control thresholds also showed lower preferences for risky alternatives in a gambling task. Furthermore, residual correlations among the heuristic and biases tasks were reduced to null, indicating that cognitive abilities, monitoring confidence, and control thresholds accounted for their shared variance. Implications include the proposal that the capacity to detect errors does not differ between individuals. Rather, individuals might adopt varied strategies that promote error checking to different degrees, regardless of whether they have made a mistake or not. The results support growing evidence that decision-making involves cognitive abilities that construct actions and monitoring and control processes that manage their initiation. PMID:27790170

Cognitive Abilities, Monitoring Confidence, and Control Thresholds Explain Individual Differences in Heuristics and Biases.

PubMed

Jackson, Simon A; Kleitman, Sabina; Howie, Pauline; Stankov, Lazar

2016-01-01

In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence, and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgments, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing that lower monitoring confidence and higher control thresholds promote error checking. Participants ( N = 250) completed tasks assessing their fluid reasoning abilities, stable monitoring confidence levels, and the control threshold they impose on their decisions. They also completed seven typical heuristic and biases tasks such as the cognitive reflection test and Resistance to Framing. Using structural equation modeling, we found that individuals with higher reasoning abilities, lower monitoring confidence, and higher control threshold performed significantly and, at times, substantially better on the heuristic and biases tasks. Individuals with higher control thresholds also showed lower preferences for risky alternatives in a gambling task. Furthermore, residual correlations among the heuristic and biases tasks were reduced to null, indicating that cognitive abilities, monitoring confidence, and control thresholds accounted for their shared variance. Implications include the proposal that the capacity to detect errors does not differ between individuals. Rather, individuals might adopt varied strategies that promote error checking to different degrees, regardless of whether they have made a mistake or not. The results support growing evidence that decision-making involves cognitive abilities that construct actions and monitoring and control processes that manage their initiation.

Range-wide patterns of migratory connectivity in the western sandpiper Calidris mauri

USGS Publications Warehouse

Franks, Samantha E.; Norris, D. Ryan; Kyser, T. Kurt; Fernández, Guillermo; Schwarz, Birgit; Carmona, Roberto; Colwell, Mark A.; Sandoval, Jorge Correa; Dondua, Alexey; Gates, H. River; Haase, Ben; Hodkinson, David J.; Jiménez, Ariam; Lanctot, Richard B.; Ortego, Brent; Sandercock, Brett K.; Sanders, Felicia J.; Takekawa, John Y.; Warnock, Nils; Ydenberg, Ron C.; Lank, David B.

2012-01-01

Understanding the population dynamics of migratory animals and predicting the consequences of environmental change requires knowing how populations are spatially connected between different periods of the annual cycle. We used stable isotopes to examine patterns of migratory connectivity across the range of the western sandpiper Calidris mauri. First, we developed a winter isotope basemap from stable-hydrogen (δD), -carbon (δ13C), and -nitrogen (δ15N) isotopes of feathers grown in wintering areas. δD and δ15N values from wintering individuals varied with the latitude and longitude of capture location, while δ13C varied with longitude only. We then tested the ability of the basemap to assign known-origin individuals. Sixty percent of wintering individuals were correctly assigned to their region of origin out of seven possible regions. Finally, we estimated the winter origins of breeding and migrant individuals and compared the resulting empirical distribution against the distribution that would be expected based on patterns of winter relative abundance. For breeding birds, the distribution of winter origins differed from expected only among males in the Yukon-Kuskokwim (Y-K) Delta and Nome, Alaska. Males in the Y-K Delta originated overwhelmingly from western Mexico, while in Nome, there were fewer males from western North America and more from the Baja Peninsula than expected. An unexpectedly high proportion of migrants captured at a stopover site in the interior United States originated from eastern and southern wintering areas, while none originated from western North America. In general, we document substantial mixing between the breeding and wintering populations of both sexes, which will buffer the global population of western sandpipers from the effects of local habitat loss on both breeding and wintering grounds.

The impact of symptom stability on time frame and recall reliability in CFS.

PubMed

Evans, Meredyth; Jason, Leonard A

This study is an investigation of the potential impact of perceived symptom stability on the recall reliability of symptom severity and frequency as reported by individuals with chronic fatigue syndrome (CFS). Symptoms were recalled using three different recall timeframes (the past week, the past month, and the past six months) and at two assessment points (with one week in between each assessment). Participants were 51 adults (45 women and 6 men), between the ages of 29 and 66 with a current diagnosis of CFS. Multilevel Model (MLM) Analyses were used to determine the optimal recall timeframe (in terms of test-retest reliability) for reporting symptoms perceived as variable and as stable over time. Headaches were recalled more reliably when they were reported as stable over time. Furthermore, the optimal timeframe in terms of test-retest reliability for stable symptoms was highly uniform, such that all Fukuda 1 CFS symptoms were more reliably recalled at the six month timeframe. Furthermore, the optimal timeframe for CFS symptoms perceived as variable, differed across symptoms. Symptom stability and recall timeframe are important to consider in order to improve the accuracy and reliability of the current methods for diagnosing this illness.

Regulation of EMMPRIN (CD147) on monocyte subsets in patients with symptomatic coronary artery disease.

PubMed

Sturhan, Henrik; Ungern-Sternberg, Saskia N I v; Langer, Harald; Gawaz, Meinrad; Geisler, Tobias; May, Andreas E; Seizer, Peter

2015-06-01

The role of individual monocyte subsets in inflammatory cardiovascular diseases is insufficiently understood. Although the Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) regulates important processes for inflammation such as MMP-release, its expression and regulation on monocyte subsets has not been characterized. In this clinical study, blood was obtained from 80 patients with stable coronary artery disease (CAD), 49 with acute myocardial infarction (AMI) and 34 healthy controls. Monocytes were divided into 3 subsets: CD14(++)CD16(-) (low), CD14(++)CD16(+) (intermediate), CD14(+)CD16(++) (high) according to phenotypic markers analyzed by flow cytometry. Surface expression of EMMPRIN was evaluated and compared with CD36 and CD47 expression. In all patients, EMMPRIN expression was significantly different among monocyte subsets with the highest expression on "classical" CD14(++)CD16(-) monocytes. EMMPRIN was upregulated on all monocyte subsets in patients with AMI as compared to patients with stable CAD. Notably, neither CD47 nor CD36 revealed a significant difference in patients with AMI compared to patients with stable CAD. EMMPRIN could serve as a marker for classical monocytes, which is upregulated in patients with acute myocardial infarction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Utility of stable isotope analysis in studying foraging ecology of herbivores: Examples from moose and caribou

USGS Publications Warehouse

Ben-David, Merav; Shochat, Einav; Adams, Layne G.

2001-01-01

Recently, researchers emphasized that patterns of stable isotope ratios observed at the individual level are a result of an interaction between ecological, physiological, and biochemical processes. Isotopic models for herbivores provide additional complications because those mammals consume foods that have high variability in nitrogen concentrations. In addition, distribution of amino acids in plants may differ greatly from that required by a herbivore. At northern latitudes, where the growing season of vegetation is short, isotope ratios in herbivore tissues are expected to differ between seasons. Summer ratios likely reflect diet composition, whereas winter ratios would reflect diet and nutrient recycling by the animals. We tested this hypothesis using data collected from blood samples of caribou (Rangifer tarandus) and moose (Alces alces) in Denali National Park and Preserve, Alaska, USA. Stable isotope ratios of moose and caribou were significantly different from each other in late summer-autumn and winter. Also, late summer-autumn and winter ratios differed significantly between seasons in both species. Nonetheless, we were unable to evaluate whether differences in seasonal isotopic ratios were a result of diet selection or a response to nutrient recycling. We believe that additional studies on plant isotopic ratios as related to ecological factors in conjunction with investigations of diet selection by the herbivores will enhance our understanding of those interactions. Also, controlled studies investigating the relation between diet and physiological responses in herbivores will increase the utility of isotopic analysis in studying foraging ecology of herbivores.

Minimal important difference for 6-minute walk test distances among patients with chronic heart failure.

PubMed

Täger, Tobias; Hanholz, Wiebke; Cebola, Rita; Fröhlich, Hanna; Franke, Jennifer; Doesch, Andreas; Katus, Hugo A; Wians, Frank H; Frankenstein, Lutz

2014-09-01

The 6-minute walk test (6 WT) is an established tool in the assessment of endurance and prognosis in patients with chronic heart failure (CHF). For these patients there is very limited data on biological variation of 6 WT distances. We determined the minimal important difference (MID) for the 6 WT in patients with stable systolic CHF. Two cohorts of patients with stable systolic CHF were included from the outpatients' clinic of the University of Heidelberg. In these cohorts, two 6 WT measurements were performed - in cohort 1 (n=461) 180 days and in cohort 2 (n=512) 365 days apart. Stability was defined as the absence of clinical events (3 months before the first test, between both tests, and 6 months after the second test) and stability of symptoms (NYHA) between tests. Using a standard error of measurement (SEM)-based approach, we determined the MID for both cohorts. The intraclass correlation coefficient was 0.89 at 180 days and 0.88 at 365 days. The results were consistent for groups stratified for age, gender, etiology of CHF, and individual NYHA class. The MID for the 6 WT in stable CHF patients was 35 m and 37 m between presentation and 180 and 365 days, respectively. Submaximal exercise capacity as represented by the 6 WT varies little in stable CHF patients for up to 1-year intervals. The MID for changes in 6 WT values in patients with stable CHF over a period of 6 to 12 months is ~ 36 m. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The role of one-shot learning in #TheDress.

PubMed

Drissi Daoudi, Leila; Doerig, Adrien; Parkosadze, Khatuna; Kunchulia, Marina; Herzog, Michael H

2017-03-01

#TheDress is remarkable in two aspects. First, there is a bimodal split of the population in the perception of the dress's colors (white/gold vs. black/blue). Second, whereas interobserver variance is high, intra-observer variance is low, i.e., the percept rarely switches in a given individual. There are two plausible routes of explanations: either one-shot learning during the first presentation of the image splits observers into two different, stable populations, or the differences are caused by stable traits of observers, such as different visual systems. Here, we hid large parts of the image by white occluders. The majority of naïve participants perceived the dress as black and blue. With black occluders, the majority of observers perceived the dress as white and gold. The percept did not change when we subsequently presented the full image, arguing for a crucial role of one-shot learning. Next, we investigated whether the first fixation determines the perceived color in naïve observers. We found no such effect. It remains thus a puzzling question where the source of variability in the different percepts comes from.

RNAi-dependent and -independent antiviral phenotypes of chromosomally integrated shRNA clones: role of VASP in respiratory syncytial virus growth.

PubMed

Musiyenko, Alla; Bitko, Vira; Barik, Sailen

2007-07-01

Stable RNA interference (RNAi) is commonly achieved by recombinant expression of short hairpin RNA (shRNA). To generate virus-resistant cell lines, we cloned a shRNA cassette against the phosphoprotein gene of respiratory syncytial virus (RSV) into a polIII-driven plasmid vector. Analysis of individual stable transfectants showed a spectrum of RSV resistance correlating with the levels of shRNA expressed from different chromosomal locations. Interestingly, resistance in a minority of clones was due to mono-allelic disruption of the cellular gene for vasodilator-stimulated phosphoprotein (VASP). Thus, pure clones of chromosomally integrated DNA-directed RNAi can exhibit gene disruption phenotypes resembling but unrelated to RNAi.

Thermal, Structural, and Optical Analysis of a Balloon-Based Imaging System

NASA Astrophysics Data System (ADS)

Borden, Michael; Lewis, Derek; Ochoa, Hared; Jones-Wilson, Laura; Susca, Sara; Porter, Michael; Massey, Richard; Clark, Paul; Netterfield, Barth

2017-03-01

The Subarcsecond Telescope And BaLloon Experiment, STABLE, is the fine stage of a guidance system for a high-altitude ballooning platform designed to demonstrate subarcsecond pointing stability over one minute using relatively dim guide stars in the visible spectrum. The STABLE system uses an attitude rate sensor and the motion of the guide star on a detector to control a Fast Steering Mirror to stabilize the image. The characteristics of the thermal-optical-mechanical elements in the system directly affect the quality of the point-spread function of the guide star on the detector, so a series of thermal, structural, and optical models were built to simulate system performance and ultimately inform the final pointing stability predictions. This paper describes the modeling techniques employed in each of these subsystems. The results from those models are discussed in detail, highlighting the development of the worst-case cold and hot cases, the optical metrics generated from the finite element model, and the expected STABLE residual wavefront error and decenter. Finally, the paper concludes with the predicted sensitivities in the STABLE system, which show that thermal deadbanding, structural pre-loading, and self-deflection under different loading conditions, and the speed of individual optical elements were particularly important to the resulting STABLE optical performance.

Deficits in agency in schizophrenia, and additional deficits in body image, body schema, and internal timing, in passivity symptoms.

PubMed

Graham, Kyran T; Martin-Iverson, Mathew T; Holmes, Nicholas P; Jablensky, Assen; Waters, Flavie

2014-01-01

Individuals with schizophrenia, particularly those with passivity symptoms, may not feel in control of their actions, believing them to be controlled by external agents. Cognitive operations that contribute to these symptoms may include abnormal processing in agency as well as body representations that deal with body schema and body image. However, these operations in schizophrenia are not fully understood, and the questions of general versus specific deficits in individuals with different symptom profiles remain unanswered. Using the projected-hand illusion (a digital video version of the rubber-hand illusion) with synchronous and asynchronous stroking (500 ms delay), and a hand laterality judgment task, we assessed sense of agency, body image, and body schema in 53 people with clinically stable schizophrenia (with a current, past, and no history of passivity symptoms) and 48 healthy controls. The results revealed a stable trait in schizophrenia with no difference between clinical subgroups (sense of agency) and some quantitative (specific) differences depending on the passivity symptom profile (body image and body schema). Specifically, a reduced sense of self-agency was a common feature of all clinical subgroups. However, subgroup comparisons showed that individuals with passivity symptoms (both current and past) had significantly greater deficits on tasks assessing body image and body schema, relative to the other groups. In addition, patients with current passivity symptoms failed to demonstrate the normal reduction in body illusion typically seen with a 500 ms delay in visual feedback (asynchronous condition), suggesting internal timing problems. Altogether, the results underscore self-abnormalities in schizophrenia, provide evidence for both trait abnormalities and state changes specific to passivity symptoms, and point to a role for internal timing deficits as a mechanistic explanation for external cues becoming a possible source of self-body input.

High intraspecific variability in the functional niche of a predator is associated with ontogenetic shift and individual specialization

PubMed Central

Zhao, Tian; Villéger, Sébastien; Lek, Sovan; Cucherousset, Julien

2014-01-01

Investigations on the functional niche of organisms have primarily focused on differences among species and tended to neglect the potential effects of intraspecific variability despite the fact that its potential ecological and evolutionary importance is now widely recognized. In this study, we measured the distribution of functional traits in an entire population of largemouth bass (Micropterus salmoides) to quantify the magnitude of intraspecific variability in functional traits and niche (size, position, and overlap) between age classes. Stable isotope analyses (δ13C and δ15N) were also used to determine the association between individual trophic ecology and intraspecific functional trait variability. We observed that functional traits were highly variable within the population (mean coefficient variation: 15.62% ± 1.78% SE) and predominantly different between age classes. In addition, functional and trophic niche overlap between age classes was extremely low. Differences in functional niche between age classes were associated with strong changes in trophic niche occurring during ontogeny while, within age classes, differences among individuals were likely driven by trophic specialization. Each age class filled only a small portion of the total functional niche of the population and age classes occupied distinct portions in the functional space, indicating the existence of ontogenetic specialists with different functional roles within the population. The high amplitude of intraspecific variability in functional traits and differences in functional niche position among individuals reported here supports the recent claims for an individual-based approach in functional ecology. PMID:25558359

Does Repeated Testing Impact Concordance Between Genital and Self-Reported Sexual Arousal in Women?

PubMed

Velten, Julia; Chivers, Meredith L; Brotto, Lori A

2018-04-01

Women show a substantial variability in their genital and subjective responses to sexual stimuli. The level of agreement between these two aspects of response is termed sexual concordance and has been increasingly investigated because of its implications for understanding models of sexual response and as a potential endpoint in clinical trials of treatments to improve women's sexual dysfunction. However, interpreting changes in sexual concordance may be problematic because, to date, it still is unclear how repeated testing itself influences sexual concordance in women. We are aware of only one study that evaluated temporal stability of concordance in women, and it found no evidence of stability. However, time stability would be necessary for arguing that concordance is a stable individual difference. The main goal of this study was to investigate the test-retest reliability of sexual concordance in a sample of 30 women with sexual difficulties. Using hierarchical linear modeling, we found that sexual concordance was not influenced by repeated testing 12 weeks later, but showed test-retest reliability suggesting temporal stability. Our findings support the hypothesis that sexual concordance is a relatively stable individual difference and that changes in sexual concordance after treatment or experimental conditions could, therefore, be attributed to effects of those conditions.

Is boldness a resource-holding potential trait? Fighting prowess and changes in startle response in the sea anemone, Actinia equina.

PubMed

Rudin, Fabian S; Briffa, Mark

2012-05-22

Contest theory predicts the evolution of a stable mixture of different strategies for fighting. Here, we investigate the possibility that stable between-individual differences in startle-response durations influence fighting ability or 'resource-holding potential' (RHP) in the beadlet sea anemone, Actinia equina. Both winners and losers showed significant repeatability of pre-fight startle-response durations but mean pre-fight startle-response durations were greater for eventual losers than for eventual winners, indicating that RHP varies with boldness. In particular, individuals with short startle responses inflicted more attacks on their opponent. Both repeatability and mean-level responses were changed by the experience of fighting, and these changes varied with outcome. In losers, repeatability was disrupted to a greater extent and the mean startle-response durations were subject to a greater increase than in winners. Thus, following a fight, this behavioural correlate of RHP behaves in a way similar to post-fight changes in physiological status, which can also vary between winners and losers. Understanding the links between aggression and boldness therefore has the potential to enhance our understanding of both the evolution of animal personality and the 'winner and loser effects' of post-fight changes in RHP.

Ultrasound assisted synthesis of stable oil in milk emulsion: Study of operating parameters and scale-up aspects.

PubMed

Patil, Leena; Gogate, Parag R

2018-01-01

In the present work, application of ultrasound and stirring individually or in combination for improved emulsification of turmeric oil in skimmed milk has been investigated. The effect of different operating parameters/strategies such as addition of surfactant, sodium dodecyl sulfate (SDS), at different concentrations, quantity of oil phase, applied power, sonication time and duty cycle on the droplet size have been investigated. The stability of emulsion was analyzed in terms of the fraction of the emulsion that remains stable for a period of 28days. Optimized set of major emulsification process variables has been used at higher emulsion volumes. The effectiveness of treatment approach was analyzed based on oil droplet size, energy density and the time required for the formation of stable emulsion. It was observed that the stable emulsion at 50mL capacity with mean droplet diameter of about 235.4nm was obtained with the surfactant concentration of 5mg/mL, 11% of rated power (power density: 0.31W/mL) and irradiation time of 5min. The emulsion stability was higher in the case of ultrasound assisted approach as compared to the stirring. For the preparation of stable emulsion at 300mL capacity, it was observed that the sequential approach, i.e., stirring followed by ultrasound, gave lower mean droplet diameter (232.6nm) than the simultaneous approach, i.e., ultrasound and stirring together (257.9nm). However, the study also revealed that the simultaneous approach required very less time (15min) to synthesize stable emulsion as compared to the sequential approach (30min stirring and 60min ultrasound). It was successfully demonstrated that the ultrasound-assisted emulsification in the presence of SDS could be used for the preparation of stable turmeric oil-dairy emulsions, also providing insights into the role of SDS in increasing the stability of emulsions and of ultrasound in giving lower droplet sizes. Copyright © 2017 Elsevier B.V. All rights reserved.

Insights into Wilson's Warbler migration from analyses of hydrogen stable-isotope ratios

Treesearch

Jeffrey F. Kelly; Viorel Atudorei; Zachary D. Sharp; Deborah M. Finch

2002-01-01

Our ability to link the breeding locations of individual passerines to migration stopover sites and wintering locations is limited. Stable isotopes of hydrogen contained in bird feathers have recently shown potential in this regard. We measured hydrogen stable-isotope ratios (deltaD) of feathers from breeding, migrating, and wintering Wilson's Warblers. Analyses...

Further examination of the temporal stability of alcohol demand.

PubMed

Acuff, Samuel F; Murphy, James G

2017-08-01

Demand, or the amount of a substance consumed as a function of price, is a central dependent measure in behavioral economic research and represents the relative valuation of a substance. Although demand is often utilized as an index of substance use severity and is assumed to be relatively stable, recent experimental and clinical research has identified conditions in which demand can be manipulated, such as through craving and stress inductions, and treatment. Our study examines the 1-month reliability of the alcohol purchase task in a sample of heavy drinking college students. We also analyzed reliability in subgroup of individuals whose consumption decreased, increased, or stayed the same over the 1-month period, and in individuals with moderate/severe Alcohol Use Disorder (AUD) vs. those with no/mild AUD. Reliability was moderate in the full sample, high in the group with stable consumption, and did not differ appreciably between AUD groups. Observed indices and indices derived from an exponentiated equation (Koffarnus et al., 2015) were generally comparable, although P max observed had very low reliability. Area under the curve, O max derived, and essential value showed the greatest reliability in the full sample (rs=0.75-0.77). These results provide evidence for the relative stability over time of demand and across AUD groups, particularly in those whose consumption remains stable. Copyright © 2017 Elsevier B.V. All rights reserved.

Crevicular fluid biomarkers and periodontal disease progression.

PubMed

Kinney, Janet S; Morelli, Thiago; Oh, Min; Braun, Thomas M; Ramseier, Christoph A; Sugai, Jim V; Giannobile, William V

2014-02-01

Assess the ability of a panel of gingival crevicular fluid (GCF) biomarkers as predictors of periodontal disease progression (PDP). In this study, 100 individuals participated in a 12-month longitudinal investigation and were categorized into four groups according to their periodontal status. GCF, clinical parameters and saliva were collected bi-monthly. Subgingival plaque and serum were collected bi-annually. For 6 months, no periodontal treatment was provided. At 6 months, patients received periodontal therapy and continued participation from 6 to 12 months. GCF samples were analysed by ELISA for MMP-8, MMP-9, Osteoprotegerin, C-reactive Protein and IL-1β. Differences in median levels of GCF biomarkers were compared between stable and progressing participants using Wilcoxon Rank Sum test (p = 0.05). Clustering algorithm was used to evaluate the ability of oral biomarkers to classify patients as either stable or progressing. Eighty-three individuals completed the 6-month monitoring phase. With the exception of GCF C-reactive protein, all biomarkers were significantly higher in the PDP group compared to stable patients. Clustering analysis showed highest sensitivity levels when biofilm pathogens and GCF biomarkers were combined with clinical measures, 74% (95% CI = 61, 86). Signature of GCF fluid-derived biomarkers combined with pathogens and clinical measures provides a sensitive measure for discrimination of PDP (ClinicalTrials.gov NCT00277745). © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Stable sequential Kuhn-Tucker theorem in iterative form or a regularized Uzawa algorithm in a regular nonlinear programming problem

NASA Astrophysics Data System (ADS)

Sumin, M. I.

2015-06-01

A parametric nonlinear programming problem in a metric space with an operator equality constraint in a Hilbert space is studied assuming that its lower semicontinuous value function at a chosen individual parameter value has certain subdifferentiability properties in the sense of nonlinear (nonsmooth) analysis. Such subdifferentiability can be understood as the existence of a proximal subgradient or a Fréchet subdifferential. In other words, an individual problem has a corresponding generalized Kuhn-Tucker vector. Under this assumption, a stable sequential Kuhn-Tucker theorem in nondifferential iterative form is proved and discussed in terms of minimizing sequences on the basis of the dual regularization method. This theorem provides necessary and sufficient conditions for the stable construction of a minimizing approximate solution in the sense of Warga in the considered problem, whose initial data can be approximately specified. A substantial difference of the proved theorem from its classical same-named analogue is that the former takes into account the possible instability of the problem in the case of perturbed initial data and, as a consequence, allows for the inherited instability of classical optimality conditions. This theorem can be treated as a regularized generalization of the classical Uzawa algorithm to nonlinear programming problems. Finally, the theorem is applied to the "simplest" nonlinear optimal control problem, namely, to a time-optimal control problem.

Behavioral and neuronal determinants of negative reciprocity in the ultimatum game

PubMed Central

Hildebrandt, Andrea; Wilhelm, Oliver; Sommer, Werner

2016-01-01

The rejection of unfair offers in the ultimatum game (UG) indicates negative reciprocity. The model of strong reciprocity claims that negative reciprocity reflects prosociality because the rejecting individual is sacrificing resources in order to punish unfair behavior. However, a recent study found that the rejection rate of unfair offers is linked to assertiveness (status defense model). To pursue the question what drives negative reciprocity, the present study investigated individual differences in the rejection of unfair offers along with their behavioral and neuronal determinants. We measured fairness preferences and event-related potentials (ERP) in 200 healthy participants playing a computerized version of the UG with pictures of unfair and fair proposers. Structural equation modeling (SEM) on the behavioral data corroborated both the strong reciprocity and the status defense models of human cooperation: Not only more prosocial but also more assertive individuals were more likely to show negative reciprocity by rejecting unfair offers. Experimental ERP results confirmed the feedback negativity (FN) as a neural signature of fairness processing. Multilevel SEM of brain–behavior relationships revealed that negative reciprocity was significantly associated with individual differences in FN amplitudes in response to proposers. Our results confirm stable individual differences in fairness processing at the behavioral and neuronal level. PMID:27261490

The embodiment of emotion: language use during the feeling of social emotions predicts cortical somatosensory activity.

PubMed

Saxbe, Darby E; Yang, Xiao-Fei; Borofsky, Larissa A; Immordino-Yang, Mary Helen

2013-10-01

Complex social emotions involve both abstract cognitions and bodily sensations, and individuals may differ on their relative reliance on these. We hypothesized that individuals' descriptions of their feelings during a semi-structured emotion induction interview would reveal two distinct psychological styles-a more abstract, cognitive style and a more body-based, affective style-and that these would be associated with somatosensory neural activity. We examined 28 participants' open-ended verbal responses to admiration- and compassion-provoking narratives in an interview and BOLD activity to the same narratives during subsequent functional magnetic resonance imaging scanning. Consistent with hypotheses, individuals' affective and cognitive word use were stable across emotion conditions, negatively correlated and unrelated to reported emotion strength in the scanner. Greater use of affective relative to cognitive words predicted more activation in SI, SII, middle anterior cingulate cortex and insula during emotion trials. The results suggest that individuals' verbal descriptions of their feelings reflect differential recruitment of neural regions supporting physical body awareness. Although somatosensation has long been recognized as an important component of emotion processing, these results offer 'proof of concept' that individual differences in open-ended speech reflect different processing styles at the neurobiological level. This study also demonstrates SI involvement during social emotional experience.

Assortative social learning and its implications for human (and animal?) societies.

PubMed

Katsnelson, Edith; Lotem, Arnon; Feldman, Marcus W

2014-07-01

Choosing from whom to learn is an important element of social learning. It affects learner success and the profile of behaviors in the population. Because individuals often differ in their traits and capabilities, their benefits from different behaviors may also vary. Homophily, or assortment, the tendency of individuals to interact with other individuals with similar traits, is known to affect the spread of behaviors in humans. We introduce models to study the evolution of assortative social learning (ASL), where assorting on a trait acts as an individual-specific mechanism for filtering relevant models from which to learn when that trait varies. We show that when the trait is polymorphic, ASL may maintain a stable behavioral polymorphism within a population (independently of coexistence with individual learning in a population). We explore the evolution of ASL when assortment is based on a nonheritable or partially heritable trait, and when ASL competes with different non-ASL strategies: oblique (learning from the parental generation) and vertical (learning from the parent). We suggest that the tendency to assort may be advantageous in the context of social learning, and that ASL might be an important concept for the evolutionary theory of social learning. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Correlation between the trajectory of systolic blood pressure and new renal damage in a nonhypertensive population.

PubMed

Wang, Zhi-Jun; Jia, Dao; Tian, Jun; Liu, Jie; Li, Li-Jie; Huang, Yu-Ling; Cao, Xin-Ying; Ning, Chun-Hong; Zhao, Quan-Hui; Yu, Jun-Xing; Zhang, Rui-Ying; Zhang, Ya-Jing; Gao, Jing-Sheng; Wu, Shou-Ling

2017-10-01

This study aims to investigate the correlation between the trajectory of systolic blood pressure (SBP) and new renal damage in a nonhypertensive population. This prospective cohort study included a total of 14 382 nonhypertensive individuals, employees of Kailuan Group of Companies, who took part in five healthy examinations in 2006-2007, 2008-2009, 2010-2011, 2012-2013, and 2014-2015, and had complete data. These individuals were divided into four groups according to the different trajectories of SBP: low-low, low-stable, middle-high, and high-high groups. The correlation between the trajectory of SBP and new renal damage in a nonhypertensive population was analyzed using a multivariate Cox's proportional hazard regression model. (a) A total of 14 382 individuals had complete data and the average age of these individuals was 44.6±10.8 years. Among these, 10 888 (75.7%) individuals were men and 3494 (24.3%) individuals were women. (b) These individuals were divided into four groups according to different trajectories of blood pressure: low-low group, accounting for 13.15% (blood pressure was <106 mmHg); low-stable group, accounting for 53.91% (blood pressure was between 115 and 116 mmHg); middle-high group, accounting for 28.77% (blood pressure was between 125 and 131 mmHg); and high-high group, accounting for 4.6% (blood pressure was between 126 and 151 mmHg). (c) With the increase in the trajectory of SBP, the detection rate of renal damage increased gradually. From the low-low group to the high-high group, the detection rates of estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73 m were 2.3, 2.4, 3.6, and 4.3%, respectively; the positive rates of urinary protein were 1.7, 2.9, 3.8, and 5.5%, respectively; and the detection rates of eGFR less than 60 ml/min/1.73 m or positive urinary protein were 4, 5.2, 7.3, and 9.3%, respectively (P<0.05). (d) After adjustment for other confounding factors, multivariate Cox's proportional hazard regression analysis showed that compared with the low-low group, the risk of eGFR less than 60 ml/min/1.73 m increased by nearly 1.5 times in the high-high group and in the low-stable, middle-high, and high-high groups, the risks of positive urinary protein, eGFR less than 60 ml/min/1.73 m, or positive urinary protein increased by 1.48-2.34 and 1.20-1.70 times, respectively. In a nonhypertensive population, the high trajectory of SBP is a risk factor for kidney damage.

Estimating individual contribution from group-based structural correlation networks.

PubMed

Saggar, Manish; Hosseini, S M Hadi; Bruno, Jennifer L; Quintin, Eve-Marie; Raman, Mira M; Kesler, Shelli R; Reiss, Allan L

2015-10-15

Coordinated variations in brain morphology (e.g., cortical thickness) across individuals have been widely used to infer large-scale population brain networks. These structural correlation networks (SCNs) have been shown to reflect synchronized maturational changes in connected brain regions. Further, evidence suggests that SCNs, to some extent, reflect both anatomical and functional connectivity and hence provide a complementary measure of brain connectivity in addition to diffusion weighted networks and resting-state functional networks. Although widely used to study between-group differences in network properties, SCNs are inferred only at the group-level using brain morphology data from a set of participants, thereby not providing any knowledge regarding how the observed differences in SCNs are associated with individual behavioral, cognitive and disorder states. In the present study, we introduce two novel distance-based approaches to extract information regarding individual differences from the group-level SCNs. We applied the proposed approaches to a moderately large dataset (n=100) consisting of individuals with fragile X syndrome (FXS; n=50) and age-matched typically developing individuals (TD; n=50). We tested the stability of proposed approaches using permutation analysis. Lastly, to test the efficacy of our method, individual contributions extracted from the group-level SCNs were examined for associations with intelligence scores and genetic data. The extracted individual contributions were stable and were significantly related to both genetic and intelligence estimates, in both typically developing individuals and participants with FXS. We anticipate that the approaches developed in this work could be used as a putative biomarker for altered connectivity in individuals with neurodevelopmental disorders. Copyright © 2015 Elsevier Inc. All rights reserved.

Monoatomic and dimer Mn adsorption on the Au(111) surface from first principles

NASA Astrophysics Data System (ADS)

Muñoz, Francisco; Romero, Aldo H.; Mejía-López, Jose; Morán-López, J. L.

2011-05-01

A theoretical study based on the density functional theory of the adsorption of Mn monomers and dimers on a Au-(111) surface is presented. As necessary preliminary steps, the bulk and clean surface electronic structure are calculated, which agree well with previous reports. Then, the electronic structure of the Mn adatom, chemisorbed on four different surface geometries, is analyzed. It is found that the most stable geometry is when the Mn atom is chemisorbed on threefold coordinated sites. Using this geometry for a single adatom a second Mn atom is chemisorbed and the most stable dimer geometrical structure is calculated. The lowest-energy configuration corresponds to the molecule lying parallel to the surface, adsorbed on two topological equivalent threefold coordinated sites. It is also found that the lowest-energy magnetic configuration corresponds to the antiferromagnetic arrangement with individual magnetic moments of 4.64μB. Finally, it is concluded that the dimer is not stable and should fragment at the surface.

Proinsulin is stable at room temperature for 24 hours in EDTA: A clinical laboratory analysis (adAPT 3)

PubMed Central

Davidson, Jane; McDonald, Timothy; Sutherland, Calum; Mostazir, Mohammod; VanAalten, Lidy

2017-01-01

Aims Reference laboratories advise immediate separation and freezing of samples for the assay of proinsulin, which limit its practicability for smaller centres. Following the demonstration that insulin and C-peptide are stable in EDTA at room temperature for at least 24hours, we undertook simple stability studies to establish whether the same might apply to proinsulin. Methods Venous blood samples were drawn from six adult women, some fasting, some not, aliquoted and assayed immediately and after storage at either 4°C or ambient temperature for periods from 2h to 24h. Results There was no significant variation or difference with storage time or storage condition in either individual or group analysis. Conclusion Proinsulin appears to be stable at room temperature in EDTA for at least 24h. Immediate separation and storage on ice of samples for proinsulin assay is not necessary, which will simplify sample transport, particularly for multicentre trials. PMID:28426711

Spousal Similarity in Life Satisfaction before and after Divorce

PubMed Central

Wortman, Jessica; Lucas, Richard E.

2015-01-01

Previous research has explored possible origins of individual differences in subjective well-being, focusing largely on stable, internal characteristics of traits as predictors of life satisfaction (Diener & Lucas, 1999). Although past work has demonstrated that life satisfaction is largely stable over the life span, other evidence has also demonstrated the lasting impact of life events. In this study, we use married couples as a test of the impact of life circumstances on life satisfaction, focusing on similarity in life satisfaction before and after divorce. If life satisfaction is impacted by shared life circumstances, married couples (who share life circumstances) should show greater similarity in life satisfaction before divorce than after. We tested this possibility using a dyadic latent-state-trait model that examined cross-spouse similarity in the stable and changing components of life satisfaction. Using a nationally representative panel study from Germany (Wagner, Frick & Schupp, 2007), we showed that similarity declined substantially following divorce. This suggests that life satisfaction is related to shared life circumstances. PMID:26436842

Spousal similarity in life satisfaction before and after divorce.

PubMed

Wortman, Jessica; Lucas, Richard E

2016-04-01

Previous research has explored possible origins of individual differences in subjective well-being, focusing largely on stable, internal characteristics of traits as predictors of life satisfaction (Diener & Lucas, 1999). Although past work has demonstrated that life satisfaction is largely stable over the life span, other evidence has also demonstrated the lasting impact of life events. In this study, we use married couples as a test of the impact of life circumstances on life satisfaction, focusing on similarity in life satisfaction before and after divorce. If life satisfaction is impacted by shared life circumstances, married couples (who share life circumstances) should show greater similarity in life satisfaction before divorce than after. We tested this possibility using a dyadic latent-state-trait model that examined cross-spouse similarity in the stable and changing components of life satisfaction. Using a nationally representative panel study from Germany (Wagner, Frick & Schupp, 2007), we showed that similarity declined substantially following divorce. This suggests that life satisfaction is related to shared life circumstances. (c) 2016 APA, all rights reserved).

Observed differences in learning ability of heart rate self-regulation as a function of hypnotic susceptibility

NASA Technical Reports Server (NTRS)

Cowings, P. S.

1977-01-01

Three groups of eight male and female subjects (aged 20-27 yr) categorized by low and high hypnotic susceptibility were taught to control their heart rates by means of an appropriate autogenic therapy/biofeedback technique. The experimental groups were trained by autogenic therapy and biofeedback, while the control group received only biofeedback. Significant differences are observed in all psychological test scores between subjects of high and low hypnotic susceptibility. The results confirm that (1) there are qualitative and quantitative differences between the performance of individuals with high and low hypnotic susceptibility; (2) interindividual-variability tests yield data relevant to individual performance in visceral learning tasks; (3) the combined autogenic therapy/biofeedback/verbal feedback technique is suitable for conditioning large stable autonomic responses in humans; and (4) this kind of conditioning is effective in eliminating or alleviating physiological reactions to some environmental stressors.

Family matters: Intergenerational and interpersonal processes of executive function and attentive behavior

PubMed Central

Deater-Deckard, Kirby

2014-01-01

Individual differences in self-regulation include executive function (EF) components that serve self-regulation of attentive behavior by modulating reactive responses to the environment. These factors “run in families”. The purpose of this review is to summarize a program of research that addresses familial inter-generational transmission and inter-personal processes in development. Self-regulation of attentive behavior involves inter-related aspects of executive function (EF) including attention, inhibitory control, and working memory. Individual differences in EF skills develop in systematic ways over childhood, resulting in moderately stable differences between people by early adolescence. Through complex gene-environment transactions, EF is transmitted across generations within parent-child relationships that provide powerful socialization and experiential contexts in which EF and related attentive behavior are forged and practiced. Families matter as parents regulate home environments and themselves as best they can while also supporting cognitive self-regulation of attentive behavior in their children. PMID:25197171

Integration of Stable Isotope and other Mass Spectral Data for Microbial Forensics

NASA Astrophysics Data System (ADS)

Kreuzer-Martin, H. W.; Jarman, K. H.

2008-12-01

The nascent field of microbial forensics requires the development of diverse signatures as indicators of various aspects of the production environment of microorganisms. We have characterized isotopic relationships between Bacillus subtilis ATCC 6051 spores and their growth environment, using as a database the carbon, nitrogen, oxygen and hydrogen stable isotope ratios of a total of 247 separate cultures of spores produced on a total of 32 different culture media. We have analyzed variation within individual samples, between cultures produced in tandem, and between cultures produced in the same medium but at different times in the context of using stable isotope ratios as a signature for sample matching. We have correlated the stable isotope ratios of carbon, nitrogen, oxygen, and hydrogen of growth medium nutrients or water and spores and show examples of how these relationships can be used to exclude nutrient or water samples as possible growth substrates for specific cultures. The power of stable isotope ratio data can be greatly enhanced by combining it with orthogonal datasets that speak to different aspects of an organism's production environment. We developed a Bayesian network that follows the causal relationship from culture medium recipe to spore elemental content as measured by secondary ion mass spectrometry (SIMS), carbon and nitrogen stable isotope ratios, and to the presence of residual agar by electrospray ionization MS (ESI-MS). The network was developed and tested on data from three replicate cultures of B. subtilis ATCC 49760 in broth and agar-containing versions of four different nutrient media. To test the network, data from SIMS analyses of B. subtilis 49760 produced in a different medium, from approximately 200 ESI MS analyses of B. thuringensis ATCC 58890 and B. anthracis Sterne grown in five additional media, and the stable isotope data from the 247 cultures of B. subtilis 6051 spores were used. This network was able to characterize Bacillus spores grown under multiple culture conditions with an error rate of less than 0.07 in characterizing carbon and nitrogen source, addition of metals, and presence of agar, and an error rate of 0.19 in characterizing the culture medium recipe. The integration of multiple analytical techniques allowed us to maximize the amount of information obtained from unknown source microorganisms. The Bayesian network approach allowed us to combine scientific understanding with well established statistical methodologies to characterize a microbe's growth environment without the need for reference signatures. Similar approaches could be applied to data from other scientific disciplines, as well as to other problems of attribution.

Ankle Instability Effects on Joint Position Sense When Stepping Across the Active Movement Extent Discrimination Apparatus

PubMed Central

Witchalls, Jeremy; Waddington, Gordon; Blanch, Peter; Adams, Roger

2012-01-01

Context Individuals with and without functional ankle instability have been tested for deficits in lower limb proprioception with varied results. Objective To determine whether a new protocol for testing participants' joint position sense during stepping is reliable and can detect differences between participants with unstable and stable ankles. Design Descriptive laboratory study. Setting University clinical laboratory. Patients or Other Participants Sample of convenience involving 21 young adult university students and staff. Ankle stability was categorized by score on the Cumberland Ankle Instability Tool; 13 had functional ankle instability, 8 had healthy ankles. Intervention(s) Test-retest of ankle joint position sense when stepping onto and across the Active Movement Extent Discrimination Apparatus twice, separated by an interim test, standing still on the apparatus and moving only 1 ankle into inversion. Main Outcome Measure(s) Difference in scores between groups with stable and unstable ankles and between test repeats. Results Participants with unstable ankles were worse at differentiating between inversion angles underfoot in both testing protocols. On repeated testing with the stepping protocol, performance of the group with unstable ankles was improved (Cohen d = 1.06, P = .006), whereas scores in the stable ankle group did not change in the second test (Cohen d = 0.04, P = .899). Despite this improvement, the unstable group remained worse at differentiating inversion angles on the stepping retest (Cohen d = 0.99, P = .020). Conclusions The deficits on proprioceptive tests shown by individuals with functional ankle instability improved with repeated exposure to the test situation. The learning effect may be the result of systematic exposure to ankle-angle variation that led to movement-specific learning or increased confidence when stepping across the apparatus. PMID:23182010

Individual differences in phonetic cue use in production and perception of a non-native sound contrast

PubMed Central

Schertz, Jessamyn; Cho, Taehong; Lotto, Andrew; Warner, Natasha

2015-01-01

The current work examines native Korean speakers’ perception and production of stop contrasts in their native language (L1, Korean) and second language (L2, English), focusing on three acoustic dimensions that are all used, albeit to different extents, in both languages: voice onset time (VOT), f0 at vowel onset, and closure duration. Participants used all three cues to distinguish the L1 Korean three-way stop distinction in both production and perception. Speakers’ productions of the L2 English contrasts were reliably distinguished using both VOT and f0 (even though f0 is only a very weak cue to the English contrast), and, to a lesser extent, closure duration. In contrast to the relative homogeneity of the L2 productions, group patterns on a forced-choice perception task were less clear-cut, due to considerable individual differences in perceptual categorization strategies, with listeners using either primarily VOT duration, primarily f0, or both dimensions equally to distinguish the L2 English contrast. Differences in perception, which were stable across experimental sessions, were not predicted by individual variation in production patterns. This work suggests that reliance on multiple cues in representation of a phonetic contrast can form the basis for distinct individual cue-weighting strategies in phonetic categorization. PMID:26644630

Sight and sound persistently out of synch: stable individual differences in audiovisual synchronisation revealed by implicit measures of lip-voice integration

PubMed Central

Ipser, Alberta; Agolli, Vlera; Bajraktari, Anisa; Al-Alawi, Fatimah; Djaafara, Nurfitriani; Freeman, Elliot D.

2017-01-01

Are sight and sound out of synch? Signs that they are have been dismissed for over two centuries as an artefact of attentional and response bias, to which traditional subjective methods are prone. To avoid such biases, we measured performance on objective tasks that depend implicitly on achieving good lip-synch. We measured the McGurk effect (in which incongruent lip-voice pairs evoke illusory phonemes), and also identification of degraded speech, while manipulating audiovisual asynchrony. Peak performance was found at an average auditory lag of ~100 ms, but this varied widely between individuals. Participants’ individual optimal asynchronies showed trait-like stability when the same task was re-tested one week later, but measures based on different tasks did not correlate. This discounts the possible influence of common biasing factors, suggesting instead that our different tasks probe different brain networks, each subject to their own intrinsic auditory and visual processing latencies. Our findings call for renewed interest in the biological causes and cognitive consequences of individual sensory asynchronies, leading potentially to fresh insights into the neural representation of sensory timing. A concrete implication is that speech comprehension might be enhanced, by first measuring each individual’s optimal asynchrony and then applying a compensatory auditory delay. PMID:28429784

Gender, level of participation, and type of sport: differences in achievement goal orientation and attributional style.

PubMed

Hanrahan, Stephanie J; Cerin, Ester

2009-07-01

Findings regarding gender differences in achievement goal orientations and attributional style have been somewhat inconsistent. One possible explanation for varied findings is that potentially confounding variables such as level of participation and type of sport have not been considered. Athletes (108 males and 164 females) from team and individual sports, competing at recreational and competitive levels, completed the Task and Ego Orientation in Sport Questionnaire, the Sport Attributional Style Scale, and a demographic questionnaire. Athletes competing in individual sports had a higher ego orientation than those from team sports, and females scored higher in task orientation than males. Individual sport athletes made more internal, stable, and global, and less externally controllable attributions for positive events, and more internal attributions for negative events than team sport athletes. Competitive female athletes made less global attributions for positive events than did recreational female athletes. This difference was not observed in male athletes. Competitive individual, but not team, athletes made less global attributions than recreational individual athletes. The significant interactions regarding globality suggest that the tradition in sport psychology attribution research to focus solely on internality, stability, and controllability may be inadequate. From an applied perspective, sport psychologists and coaches may find it beneficial to target individual sport athletes and males for interventions designed to enhance task orientation. Similarly, team sport athletes may be appropriate as a focus for attribution retraining programs.

Consistent inter-individual differences in common marmosets (Callithrix jacchus) in Boldness-Shyness, Stress-Activity, and Exploration-Avoidance.

PubMed

Šlipogor, Vedrana; Gunhold-de Oliveira, Tina; Tadić, Zoran; Massen, Jorg J M; Bugnyar, Thomas

2016-09-01

The study of animal personality, defined as consistent inter-individual differences in correlated behavioral traits stable throughout time and/or contexts, has recently become one of the fastest growing areas in animal biology, with study species ranging from insects to non-human primates. The latter have, however, only occasionally been tested with standardized experiments. Instead their personality has usually been assessed using questionnaires. Therefore, this study aimed to test 21 common marmosets (Callithrix jacchus) living in three family groups, in five different experiments, and their corresponding controls. We found that behavioral differences between our animals were not only consistent over time, but also across different contexts. Moreover, the consistent behaviors formed a construct of four major non-social personality components: Boldness-Shyness in Foraging, Boldness-Shyness in Predation, Stress-Activity, and Exploration-Avoidance. We found no sex or age differences in these components, but our results did reveal differences in Exploration-Avoidance between the three family groups. As social environment can have a large influence on behavior of individuals, our results may suggest group-level similarity in personality (i.e., "group personality") in common marmosets, a species living in highly cohesive social groups. Am. J. Primatol. 78:961-973, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Retrospective characterization of ontogenetic shifts in killer whale diets via δ13C and δ15N analysis of teeth

USGS Publications Warehouse

Newsome, Seth D.; Etnier, Michael A.; Monson, Daniel H.; Fogel, Marilyn L.

2009-01-01

Metabolically inert, accretionary structures such as the dentin growth layers in teeth provide a life history record of individual diet with near-annual resolution. We constructed ontogenetic ??13C and ??15N profiles by analyzing tooth dentin growth layers from 13 individual killer whales Orcinus orca collected in the eastern northeast Pacific Ocean between 1961 and 2003. The individuals sampled were 6 to 52 yr old, representing 2 ecotypes-resident and transient - collected across ???25?? of latitude. The average isotopic values of transient individuals (n = 10) are consistent with a reliance on mammalian prey, while the average isotopic values of residents (n = 3) are consistent with piscivory. Regardless of ecotype, most individuals show a decrease in ??15N values of ???2.5% through the first 3 yr of life, roughly equivalent to a decrease of one trophic level. We interpret this as evidence of gradual weaning, after which, ontogenetic shifts in isotopic values are highly variable. A few individuals (n = 2) maintained relatively stable ??15N and ??13C values throughout the remainder of their lives, whereas ??15N values of most (n = 11) increased by ???1.5%, suggestive of an ontogenetic increase in trophic level. Significant differences in mean ??13C and ??15N values among transients collected off California suggest that individuality in prey preferences may be prevalent within this ecotype. Our approach provides retrospective individual life history and dietary information that cannot be obtained through traditional field observations of free-ranging and elusive species such as killer whales, including unique historic ecological information that pre-dates modern studies. By providing insights into individual diet composition, stable isotope analysis of teeth and/or bones may be the only means of evaluating a number of hypothesized historical dietary shifts in killer whales of the northeast Pacific Ocean. ?? Inter-Research 2009.

Retrospective characterization of ontogenetic shifts in killer whale diets via δ13C and δ15N analysis of teeth

USGS Publications Warehouse

Newsome, Seth D.; Etnier, Michael A.; Monson, Daniel H.; Fogel, Marilyn L.

2009-01-01

Metabolically inert, accretionary structures such as the dentin growth layers in teeth provide a life history record of individual diet with near-annual resolution. We constructed ontogenetic δ13C and δ15N profiles by analyzing tooth dentin growth layers from 13 individual killer whales Orcinus orca collected in the eastern northeast Pacific Ocean between 1961 and 2003. The individuals sampled were 6 to 52 yr old, representing 2 ecotypes—resident and transient—collected across ~25° of latitude. The average isotopic values of transient individuals (n = 10) are consistent with a reliance on mammalian prey, while the average isotopic values of residents (n = 3) are consistent with piscivory. Regardless of ecotype, most individuals show a decrease in δ15N values of ~2.5‰ through the first 3 yr of life, roughly equivalent to a decrease of one trophic level. We interpret this as evidence of gradual weaning, after which, ontogenetic shifts in isotopic values are highly variable. A few individuals (n = 2) maintained relatively stable δ15N and δ13C values throughout the remainder of their lives, whereas δ15N values of most (n = 11) increased by ~1.5‰, suggestive of an ontogenetic increase in trophic level. Significant differences in mean δ13C and δ15N values among transients collected off California suggest that individuality in prey preferences may be prevalent within this ecotype. Our approach provides retrospective individual life history and dietary information that cannot be obtained through traditional field observations of free-ranging and elusive species such as killer whales, including unique historic ecological information that pre-dates modern studies. By providing insights into individual diet composition, stable isotope analysis of teeth and/or bones may be the only means of evaluating a number of hypothesized historical dietary shifts in killer whales of the northeast Pacific Ocean

Lipid Extraction Techniques for Stable Isotope Analysis and Ecological Assays.

PubMed

Elliott, Kyle H; Roth, James D; Crook, Kevin

2017-01-01

Lipid extraction is an important component of many ecological and ecotoxicological measurements. For instance, percent lipid is often used as a measure of body condition, under the assumption that those individuals with higher lipid reserves are healthier. Likewise, lipids are depleted in 13 C compared with protein, and it is consequently a routine to remove lipids prior to measuring carbon isotopes in ecological studies so that variation in lipid content does not obscure variation in diet. We provide detailed methods for two different protocols for lipid extraction: Soxhlet apparatus and manual distillation. We also provide methods for polar and nonpolar solvents. Neutral (nonpolar) solvents remove some lipids but few non-lipid compounds, whereas polar solvents remove most lipids but also many non-lipid compounds. We discuss each of the methods and provide guidelines for best practices. We recommend that, for stable isotope analysis, researchers test for a relationship between the change in carbon stable isotope ratio and the amount of lipid extracted to see if the degree of extraction has an impact on isotope ratios. Stable isotope analysis is widely used by ecologists, and we provide a detailed methodology that minimizes known biases.

Plasticity varies with boldness in a weakly-electric fish.

PubMed

Kareklas, Kyriacos; Arnott, Gareth; Elwood, Robert W; Holland, Richard A

2016-01-01

The expression of animal personality is indicated by patterns of consistency in individual behaviour. Often, the differences exhibited between individuals are consistent across situations. However, between some situations, this can be biased by variable levels of individual plasticity. The interaction between individual plasticity and animal personality can be illustrated by examining situation-sensitive personality traits such as boldness (i.e. risk-taking and exploration tendency). For the weakly electric fish Gnathonemus petersii, light condition is a major factor influencing behaviour. Adapted to navigate in low-light conditions, this species chooses to be more active in dark environments where risk from visual predators is lower. However, G. petersii also exhibit individual differences in their degree of behavioural change from light to dark. The present study, therefore, aims to examine if an increase of motivation to explore in the safety of the dark, not only affects mean levels of boldness, but also the variation between individuals, as a result of differences in individual plasticity. Boldness was consistent between a novel-object and a novel-environment situation in bright light. However, no consistency in boldness was noted between a bright (risky) and a dark (safe) novel environment. Furthermore, there was a negative association between boldness and the degree of change across novel environments, with shier individuals exhibiting greater behavioural plasticity. This study highlights that individual plasticity can vary with personality. In addition, the effect of light suggests that variation in boldness is situation specific. Finally, there appears to be a trade-off between personality and individual plasticity with shy but plastic individuals minimizing costs when perceiving risk and bold but stable individuals consistently maximizing rewards, which can be maladaptive.

Evolution of Cooperation in Adaptive Social Networks

NASA Astrophysics Data System (ADS)

Segbroeck, Sven Van; Santos, Francisco C.; Traulsen, Arne; Lenaerts, Tom; Pacheco, Jorge M.

Humans are organized in societies, a phenomenon that would never have been possible without the evolution of cooperative behavior. Several mechanisms that foster this evolution have been unraveled over the years, with population structure as a prominent promoter of cooperation. Modern networks of exchange and cooperation are, however, becoming increasingly volatile, and less and less based on long-term stable structure. Here, we address how this change of paradigm aspects the evolution of cooperation. We discuss analytical and numerical models in which individuals can break social ties and create new ones. Interactions are modeled as two-player dilemmas of cooperation. Once a link between two individuals has formed, the productivity of this link is evaluated. Links can be broken off at different rates. This individual capacity of forming new links or severing inconvenient ones can effectively change the nature of the game. We address random formation of new links and local linking rules as well as different individual capacities to maintain social interactions. We conclude by discussing how adaptive social networks can become an important step towards more realistic models of cultural dynamics.

Molecular Phenotypes Distinguish Patients with Relatively Stable from Progressive Idiopathic Pulmonary Fibrosis (IPF)

PubMed Central

Boon, Kathy; Bailey, Nathaniel W.; Yang, Jun; Steel, Mark P.; Groshong, Steve; Kervitsky, Dolly; Brown, Kevin K.; Schwarz, Marvin I.; Schwartz, David A.

2009-01-01

Background Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic interstitial lung disease that is unresponsive to current therapy and often leads to death. However, the rate of disease progression differs among patients. We hypothesized that comparing the gene expression profiles between patients with stable disease and those in which the disease progressed rapidly will lead to biomarker discovery and contribute to the understanding of disease pathogenesis. Methodology and Principal Findings To begin to address this hypothesis, we applied Serial Analysis of Gene Expression (SAGE) to generate lung expression profiles from diagnostic surgical lung biopsies in 6 individuals with relatively stable (or slowly progressive) IPF and 6 individuals with progressive IPF (based on changes in DLCO and FVC over 12 months). Our results indicate that this comprehensive lung IPF SAGE transcriptome is distinct from normal lung tissue and other chronic lung diseases. To identify candidate markers of disease progression, we compared the IPF SAGE profiles in stable and progressive disease, and identified a set of 102 transcripts that were at least 5-fold up regulated and a set of 89 transcripts that were at least 5-fold down regulated in the progressive group (P-value≤0.05). The over expressed genes included surfactant protein A1, two members of the MAPK-EGR-1-HSP70 pathway that regulate cigarette-smoke induced inflammation, and Plunc (palate, lung and nasal epithelium associated), a gene not previously implicated in IPF. Interestingly, 26 of the up regulated genes are also increased in lung adenocarcinomas and have low or no expression in normal lung tissue. More importantly, we defined a SAGE molecular expression signature of 134 transcripts that sufficiently distinguished relatively stable from progressive IPF. Conclusions These findings indicate that molecular signatures from lung parenchyma at the time of diagnosis could prove helpful in predicting the likelihood of disease progression or possibly understanding the biological activity of IPF. PMID:19347046

Stoichiometric control of multiple different tectons in coordination-driven self-assembly: preparation of fused metallacyclic polygons.

PubMed

Lee, Junseong; Ghosh, Koushik; Stang, Peter J

2009-09-02

We present a general strategy for the synthesis of stable, multicomponent fused polygon complexes in which coordination-driven self-assembly allows for single supramolecular species to be formed from multicomponent self-assembly and the shape of the obtained polygons can be controlled simply by changing the ratio of individual components. The compounds have been characterized by multinuclear NMR spectroscopy and electrospray ionization mass spectrometry.

Individual differences in face-looking behavior generalize from the lab to the world.

PubMed

Peterson, Matthew F; Lin, Jing; Zaun, Ian; Kanwisher, Nancy

2016-05-01

Recent laboratory studies have found large, stable individual differences in the location people first fixate when identifying faces, ranging from the brows to the mouth. Importantly, this variation is strongly associated with differences in fixation-specific identification performance such that individuals' recognition ability is maximized when looking at their preferred location (Mehoudar, Arizpe, Baker, & Yovel, 2014; Peterson & Eckstein, 2013). This finding suggests that face representations are retinotopic and individuals enact gaze strategies that optimize identification, yet the extent to which this behavior reflects real-world gaze behavior is unknown. Here, we used mobile eye trackers to test whether individual differences in face gaze generalize from lab to real-world vision. In-lab fixations were measured with a speeded face identification task, while real-world behavior was measured as subjects freely walked around the Massachusetts Institute of Technology campus. We found a strong correlation between the patterns of individual differences in face gaze in the lab and real-world settings. Our findings support the hypothesis that individuals optimize real-world face identification by consistently fixating the same location and thus strongly constraining the space of retinotopic input. The methods developed for this study entailed collecting a large set of high-definition, wide field-of-view natural videos from head-mounted cameras and the viewer's fixation position, allowing us to characterize subjects' actually experienced real-world retinotopic images. These images enable us to ask how vision is optimized not just for the statistics of the "natural images" found in web databases, but of the truly natural, retinotopic images that have landed on actual human retinae during real-world experience.

The movement ecology of the straw-colored fruit bat, Eidolon helvum, in sub-Saharan Africa assessed by stable isotope ratios.

PubMed

Ossa, Gonzalo; Kramer-Schadt, Stephanie; Peel, Alison J; Scharf, Anne K; Voigt, Christian C

2012-01-01

Flying foxes (Pteropodidae) are key seed dispersers on the African continent, yet their migratory behavior is largely unknown. Here, we studied the movement ecology of the straw-colored fruit bat, Eidolon helvum, and other fruit bats by analyzing stable isotope ratios in fur collected from museum specimens. In a triple-isotope approach based on samples of two ecologically similar non-migratory pteropodids, we first confirmed that a stable isotope approach is capable of delineating between geographically distinct locations in Sub-Saharan Africa. A discriminant function analysis assigned 84% of individuals correctly to their capture site. Further, we assessed how well hydrogen stable isotope ratios (δ(2)H) of fur keratin collected from non-migratory species (n = 191 individuals) records variation in δ(2)H of precipitation water in sub-Saharan Africa. Overall, we found positive, negative and no correlations within the six studied species. We then developed a reduced major axis regression equation based on individual data of non-migratory species to predict where potentially migratory E. helvum (n = 88) would come from based on their keratin δ(2)H. Across non-migratory species, δ(2)H of keratin and local water correlated positively. Based on the isoscape origin model, 22% of E. helvum were migratory, i.e. individuals had migrated over at least 250 km prior to their capture. Migratory individuals came from locations at a median distance of about 860 km from the collection site, four even from distances of at least 2,000 km. Ground-truthing of our isoscape origin model based on keratin δ(2)H of extant E. helvum (n = 76) supported a high predictive power of assigning the provenance of African flying foxes. Our study highlights that stable isotope ratios can be used to explain the migratory behavior of flying foxes, even on the isotopically relatively homogenous African continent, and with material collected by museums many decades or more than a century ago.

Temporal Stability of the Human Skin Microbiome.

PubMed

Oh, Julia; Byrd, Allyson L; Park, Morgan; Kong, Heidi H; Segre, Julia A

2016-05-05

Biogeography and individuality shape the structural and functional composition of the human skin microbiome. To explore these factors' contribution to skin microbial community stability, we generated metagenomic sequence data from longitudinal samples collected over months and years. Analyzing these samples using a multi-kingdom, reference-based approach, we found that despite the skin's exposure to the external environment, its bacterial, fungal, and viral communities were largely stable over time. Site, individuality, and phylogeny were all determinants of stability. Foot sites exhibited the most variability; individuals differed in stability; and transience was a particular characteristic of eukaryotic viruses, which showed little site-specificity in colonization. Strain and single-nucleotide variant-level analysis showed that individuals maintain, rather than reacquire, prevalent microbes from the environment. Longitudinal stability of skin microbial communities generates hypotheses about colonization resistance and empowers clinical studies exploring alterations observed in disease states. Copyright © 2016 Elsevier Inc. All rights reserved.

(Sample) Size Matters: Best Practices for Defining Error in Planktic Foraminiferal Proxy Records

NASA Astrophysics Data System (ADS)

Lowery, C.; Fraass, A. J.

2016-02-01

Paleoceanographic research is a vital tool to extend modern observational datasets and to study the impact of climate events for which there is no modern analog. Foraminifera are one of the most widely used tools for this type of work, both as paleoecological indicators and as carriers for geochemical proxies. However, the use of microfossils as proxies for paleoceanographic conditions brings about a unique set of problems. This is primarily due to the fact that groups of individual foraminifera, which usually live about a month, are used to infer average conditions for time periods ranging from hundreds to tens of thousands of years. Because of this, adequate sample size is very important for generating statistically robust datasets, particularly for stable isotopes. In the early days of stable isotope geochemistry, instrumental limitations required hundreds of individual foraminiferal tests to return a value. This had the fortunate side-effect of smoothing any seasonal to decadal changes within the planktic foram population. With the advent of more sensitive mass spectrometers, smaller sample sizes have now become standard. While this has many advantages, the use of smaller numbers of individuals to generate a data point has lessened the amount of time averaging in the isotopic analysis and decreased precision in paleoceanographic datasets. With fewer individuals per sample, the differences between individual specimens will result in larger variation, and therefore error, and less precise values for each sample. Unfortunately, most (the authors included) do not make a habit of reporting the error associated with their sample size. We have created an open-source model in R to quantify the effect of sample sizes under various realistic and highly modifiable parameters (calcification depth, diagenesis in a subset of the population, improper identification, vital effects, mass, etc.). For example, a sample in which only 1 in 10 specimens is diagenetically altered can be off by >0.3‰ δ18O VPDB, or 1°C. Here, we demonstrate the use of this tool to quantify error in micropaleontological datasets, and suggest best practices for minimizing error when generating stable isotope data with foraminifera.

Competitive helping increases with the size of biological markets and invades defection.

PubMed

Barclay, Pat

2011-07-21

Cooperation between unrelated individuals remains a puzzle in evolutionary biology. Recent work indicates that partner choice can select for high levels of helping. More generally, helping can be seen as but one strategy used to compete for partners within a broader biological market, yet giving within such markets has received little mathematical investigation. In the present model, individuals help others to attract attention from them and thus receive a larger share of any help actively or passively provided by those others. The evolutionarily stable level of helping increases with the size of the biological market and the degree of partner choice. Furthermore, if individuals passively produce some no-cost help to partners, competitive helping can then invade populations of non-helpers because helpers directly benefit from increasing their access to potential partners. This framework of competitive helping demonstrates how high helping can be achieved and why different populations may differ in helping levels. Copyright © 2011 Elsevier Ltd. All rights reserved.

Predicting future learning from baseline network architecture.

PubMed

Mattar, Marcelo G; Wymbs, Nicholas F; Bock, Andrew S; Aguirre, Geoffrey K; Grafton, Scott T; Bassett, Danielle S

2018-05-15

Human behavior and cognition result from a complex pattern of interactions between brain regions. The flexible reconfiguration of these patterns enables behavioral adaptation, such as the acquisition of a new motor skill. Yet, the degree to which these reconfigurations depend on the brain's baseline sensorimotor integration is far from understood. Here, we asked whether spontaneous fluctuations in sensorimotor networks at baseline were predictive of individual differences in future learning. We analyzed functional MRI data from 19 participants prior to six weeks of training on a new motor skill. We found that visual-motor connectivity was inversely related to learning rate: sensorimotor autonomy at baseline corresponded to faster learning in the future. Using three additional scans, we found that visual-motor connectivity at baseline is a relatively stable individual trait. These results suggest that individual differences in motor skill learning can be predicted from sensorimotor autonomy at baseline prior to task execution. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Adaptive disengagement buffers self-esteem from negative social feedback.

PubMed

Leitner, Jordan B; Hehman, Eric; Deegan, Matthew P; Jones, James M

2014-11-01

The degree to which self-esteem hinges on feedback in a domain is known as a contingency of self-worth, or engagement. Although previous research has conceptualized engagement as stable, it would be advantageous for individuals to dynamically regulate engagement. The current research examined whether the tendency to disengage from negative feedback accounts for variability in self-esteem. We created the Adaptive Disengagement Scale (ADS) to capture individual differences in the tendency to disengage self-esteem from negative outcomes. Results demonstrated that the ADS is reliable and valid (Studies 1 and 2). Furthermore, in response to negative social feedback, higher scores on the ADS predicted greater state self-esteem (Study 3), and this relationship was mediated by disengagement (Study 4). These findings demonstrate that adaptive disengagement protects self-esteem from negative outcomes and that the ADS is a valid measure of individual differences in the implementation of this process. © 2014 by the Society for Personality and Social Psychology, Inc.

Fine-Scale Spatial Variability of Precipitation, Soil, and Plant Water Isotopes

NASA Astrophysics Data System (ADS)

Goldsmith, G. R.; Braun, S.; Romero, C.; Engbersen, N.; Gessler, A.; Siegwolf, R. T.; Schmid, L.

2015-12-01

Introduction: The measurement of stable isotope ratios of water has become fundamental in advancing our understanding of environmental patterns and processes, particularly with respect to understanding the movement of water within the soil-plant-atmosphere continuum. While considerable research has explored the temporal variation in stable isotope ratios of water in the environment, our understanding of the spatial variability of these isotopes remains poorly understood. Methods: We collected spatially explicit samples of throughfall and soil water (n=150 locations) from a 1 ha plot delineated in a mixed deciduous forest in the northern Alps of Switzerland. We complemented this with fully sunlit branch and leaf samples (n = 60 individuals) collected from Picea abies and Fagus sylvatica between 14:00 and 16:00 on the same day by means of a helicopter. Soil and plant waters were extracted using cryogenic vacuum distillation and all samples were analyzed for δ18O using an isotope ratio mass spectrometer. Results: The mean δ18O of throughfall (-3.3 ± 0.8‰) indicated some evaporative enrichment associated with passage through the canopy, but this did not significantly differ from the precipitation collected in nearby open sites (-4.05‰). However, soil was depleted (-7.0 ± 1.8‰) compared to throughfall and there was no significant relationship between the two, suggesting that the sampling for precipitation inputs did not capture all the sources (e.g. stream water, which was -11.5‰) contributing to soil water δ18O ratios. Evaporative enrichment of δ18O was higher in leaves of Fagus (14.8 ± 1.8‰) than in leaves of Picea (11.8 ± 1.7‰). Sampling within crowns of each species (n = 5 branches each from 5 individuals) indicated that variability in a single individual is similar to that among individuals. Discussion: Stable isotopes of water are frequently engaged for studies of ecohydrology, plant ecophysiology, and paleoclimatology. Our results help constrain the variability within different water sources across space (e.g. when vizualized as isoscapes), as well as the extent of fractionation among those sources as water moves through the critical zone. In doing so, we also provide insight into how environment shapes this fine-scale variation in order to inform future applications of water isotopes.

Stable hydrogen isotope analysis of bat hair as evidence for seasonal molt and long-distance migration

USGS Publications Warehouse

Cryan, P.M.; Bogan, M.A.; Rye, R.O.; Landis, G.P.; Kester, C.L.

2004-01-01

Although hoary bats (Lasiurus cinereus) are presumed to be migratory and capable of long-distance dispersal, traditional marking techniques have failed to provide direct evidence of migratory movements by individuals. We measured the stable hydrogen isotope ratios of bat hair (δDh) and determined how these values relate to stable hydrogen isotope ratios of precipitation (δDp). Our results indicate that the major assumptions of stable isotope migration studies hold true for hoary bats and that the methodology provides a viable means of determining their migratory movements. We present evidence that a single annual molt occurs in L. cinereus prior to migration and that there is a strong relationship between δDh and δDp during the molt period. This presumably reflects the incorporation of local δDp into newly grown hair. Furthermore, we present evidence that individual hoary bats are capable of traveling distances in excess of 2,000 km and that hair is grown at a wide range of latitudes and elevations. Stable hydrogen isotope analysis offers a promising new tool for the study of bat migration.

No Associations between Interindividual Differences in Sleep Parameters and Episodic Memory Consolidation.

PubMed

Ackermann, Sandra; Hartmann, Francina; Papassotiropoulos, Andreas; de Quervain, Dominique J-F; Rasch, Björn

2015-06-01

Sleep and memory are stable and heritable traits that strongly differ between individuals. Sleep benefits memory consolidation, and the amount of slow wave sleep, sleep spindles, and rapid eye movement sleep have been repeatedly identified as reliable predictors for the amount of declarative and/or emotional memories retrieved after a consolidation period filled with sleep. These studies typically encompass small sample sizes, increasing the probability of overestimating the real association strength. In a large sample we tested whether individual differences in sleep are predictive for individual differences in memory for emotional and neutral pictures. Between-subject design. Cognitive testing took place at the University of Basel, Switzerland. Sleep was recorded at participants' homes, using portable electroencephalograph-recording devices. Nine hundred-twenty-nine healthy young participants (mean age 22.48 ± 3.60 y standard deviation). None. In striking contrast to our expectations as well as numerous previous findings, we did not find any significant correlations between sleep and memory consolidation for pictorial stimuli. Our results indicate that individual differences in sleep are much less predictive for pictorial memory processes than previously assumed and suggest that previous studies using small sample sizes might have overestimated the association strength between sleep stage duration and pictorial memory performance. Future studies need to determine whether intraindividual differences rather than interindividual differences in sleep stage duration might be more predictive for the consolidation of emotional and neutral pictures during sleep. © 2015 Associated Professional Sleep Societies, LLC.

Rosiglitazone and Cognitive Stability in Older Individuals With Type 2 Diabetes and Mild Cognitive Impairment

PubMed Central

Abbatecola, Angela M.; Lattanzio, Fabrizia; Molinari, Anna M.; Cioffi, Michele; Mansi, Luigi; Rambaldi, Pierfrancesco; DiCioccio, Luigi; Cacciapuoti, Federico; Canonico, Raffaele; Paolisso, Giuseppe

2010-01-01

OBJECTIVE Studies have suggested that insulin resistance plays a role in cognitive impairment in individuals with type 2 diabetes. We aimed to determine whether an improvement in insulin resistance could explain cognitive performance variations over 36 weeks in older individuals with mild cognitive impairment (MCI) and type 2 diabetes. RESEARCH DESIGN AND METHODS A total of 97 older individuals (mean ± SD age 76 ± 6 years) who had recently (<2 months) started an antidiabetes treatment of metformin (500 mg twice a day) (n = 30) or metformin (500 mg/day)+rosiglitazone (4 mg/day) (n = 32) or diet (n = 35) volunteered. The neuropsychological test battery consisted of the Mini-Mental State Examination (MMSE), Rey Verbal Auditory Learning Test (RAVLT) total recall, and Trail Making Tests (TMT-A and TMT-B) performed at baseline and every 12 weeks for 36 weeks along with clinical testing. RESULTS At baseline, no significant differences were found between groups in clinical or neuropsychological parameters. Mean ± SD values in the entire population were as follows: A1C 7.5 ± 0.5%, fasting plasma glucose (FPG) 8.6 ± 1.3 mmol/l, fasting plasma insulin (FPI) 148 ± 74 pmol/l, MMSE 24.9 ± 2.4, TMT-A 61.6 ± 42.0, TMT-B 162.8 ± 78.7, the difference between TMT-B and TMT-A [DIFFBA] 101.2 ± 58.1, and RAVLT 24.3 ± 2.1. At follow-up, ANOVA models tested changes in metabolic control parameters (FPI, FPG, and A1C). Such parameters improved in the metformin and metformin/rosiglitazone groups (Ptrend < 0.05 in both groups). ANCOVA repeated models showed that results for the metformin/rosiglitazone group remained stable for all neuropsychological tests, and results for the diet group remained stable for the MMSE and TMT-A and declined for the TMT-B (Ptrend = 0.024), executive efficiency (DIFFBA) (Ptrend = 0.026), and RAVLT memory test (Ptrend = 0.011). Results for the metformin group remained stable for the MMSE and TMTs but declined for the RAVLT (Ptrend = 0.011). With use of linear mixed-effects models, the interaction term, FPI × time, correlated with cognitive stability on the RAVLT in the metformin/rosiglitazone group (β = −1.899; P = 0.009). CONCLUSIONS Rosiglitazone may protect against cognitive decline in older individuals with type 2 diabetes and MCI. PMID:20435794

Lapita diet and subsistence strategies on Watom Island, Papua New Guinea: New stable isotope evidence from humans and animals.

PubMed

Kinaston, Rebecca L; Anson, Dimitri; Petchey, Peter; Walter, Richard; Robb, Kasey; Buckley, Hallie

2015-05-01

Stable isotope ratios (δ(13)C and δ(15)N) were analyzed from the bone collagen of individuals (n = 8) from a Lapita burial ground (ca. 2800-2350 BP) on Watom Island, located off northeast New Britain in the Bismarck Archipelago. The aim of this study was to assess the diet and subsistence strategies of humans that lived during the later Lapita period in Near Oceania. To aid in the interpretation of the human diet we analyzed the stable isotope ratios of faunal material from the site (n = 27). We also aim to assess methods of animal husbandry at the site over time from an analysis of the stable isotope ratios (δ(13)C and δ(15)N) of pig bones (n = 22) from different temporal periods (Lapita, post-Lapita, and late prehistoric). The protein diet of the humans consisted of marine organisms from the inshore environment and some deep-water species, most likely marine turtle, in addition to higher trophic level terrestrial foods, likely pig and native animals (e.g., fruit bat, Cuscus and bandicoot). Although the sample sizes were small, females (n = 4) displayed more variable δ(13)C and δ(15)N values compared with males (n = 4), which may be associated with the movement of adult females to the island. The stable isotope analysis of the pig bones indicated that there were few differences between the diets of the pigs from the Lapita and post-Lapita layers, suggesting that the method of pig husbandry was similar between these two periods and was likely relatively free-range. © 2015 Wiley Periodicals, Inc.

Population variation in isotopic composition of shorebird feathers: Implications for determining molting grounds

USGS Publications Warehouse

Torres-Dowdall, J.; Farmer, A.H.; Bucher, E.H.; Rye, R.O.; Landis, G.

2009-01-01

Stable isotope analyses have revolutionized the study of migratory connectivity. However, as with all tools, their limitations must be understood in order to derive the maximum benefit of a particular application. The goal of this study was to evaluate the efficacy of stable isotopes of C, N, H, O and S for assigning known-origin feathers to the molting sites of migrant shorebird species wintering and breeding in Argentina. Specific objectives were to: 1) compare the efficacy of the technique for studying shorebird species with different migration patterns, life histories and habitat-use patterns; 2) evaluate the grouping of species with similar migration and habitat use patterns in a single analysis to potentially improve prediction accuracy; and 3) evaluate the potential gains in prediction accuracy that might be achieved from using multiple stable isotopes. The efficacy of stable isotope ratios to determine origin was found to vary with species. While one species (White-rumped Sandpiper, Calidris fuscicollis) had high levels of accuracy assigning samples to known origin (91% of samples correctly assigned), another (Collared Plover, Charadrius collaris) showed low levels of accuracy (52% of samples correctly assigned). Intra-individual variability may account for this difference in efficacy. The prediction model for three species with similar migration and habitat-use patterns performed poorly compared with the model for just one of the species (71% versus 91% of samples correctly assigned). Thus, combining multiple sympatric species may not improve model prediction accuracy. Increasing the number of stable isotopes in the analyses increased the accuracy of assigning shorebirds to their molting origin, but the best combination - involving a subset of all the isotopes analyzed - varied among species.

Specialist Individuals, Generalist Populations, and Gentoo Penguin Foraging Ecology Across the Scotia Arc During a Time of Rapid Environmental Change

NASA Astrophysics Data System (ADS)

Herman, R.; Polito, M. J.

2016-02-01

Populations of Gentoo penguins (Pygoscelis papua), have increased in the Scotia arc in the last four decades, while sister species such as Chinstrap (P. antarctics) and Adélie penguins (P. adeliae) have experienced substantial declines in numbers. Previous dietary analyses suggest Gentoo penguins have a generalist foraging niche, which may help buffer them from recent climate-driven declines in key prey species, such as Antarctic krill (Euphausia superba). Ecological theory indicates that generalist populations fall under two different categories: Type A generalist populations exhibit large variation within individuals, and little variation between individuals, where Type B generalist populations are comprised of individual specialists, with large variation between individuals. It is important to identify which type of generalist population Gentoo penguins fall under, as these strategies impart differing ecological and evolutionary ramifications under times of environmental change. We conducted stable isotope analysis using tail feathers from Gentoo penguins at four breeding sites across the Scotia arc, including the Falkland Islands, South Georgia, the South Shetland Islands, and the Western Antarctic Peninsula, to assess individual variation in winter diets and determine the type of generalist strategies that Gentoo penguins utilize. Preliminary analysis indicates the presence of individual specialization within the four geographically distinct breeding colonies, suggesting that individual resilience to further shifts in food availability may vary within Gentoo penguin populations.

Opinion competition dynamics on multiplex networks

NASA Astrophysics Data System (ADS)

Amato, R.; Kouvaris, N. E.; San Miguel, M.; Díaz-Guilera, A.

2017-12-01

Multilayer and multiplex networks represent a good proxy for the description of social phenomena where social structure is important and can have different origins. Here, we propose a model of opinion competition where individuals are organized according to two different structures in two layers. Agents exchange opinions according to the Abrams-Strogatz model in each layer separately and opinions can be copied across layers by the same individual. In each layer a different opinion is dominant, so each layer has a different absorbing state. Consensus in one opinion is not the only possible stable solution because of the interaction between the two layers. A new mean field solution has been found where both opinions coexist. In a finite system there is a long transient time for the dynamical coexistence of both opinions. However, the system ends in a consensus state due to finite size effects. We analyze sparse topologies in the two layers and the existence of positive correlations between them, which enables the coexistence of inter-layer groups of agents sharing the same opinion.

Trophic relationships on a fucoid shore in south-western Iceland as revealed by stable isotope analyses, laboratory experiments, field observations and gut analyses

NASA Astrophysics Data System (ADS)

Steinarsdóttir, M. B.; Ingólfsson, A.; Ólafsson, E.

2009-04-01

Rocky shores in the North Atlantic are known for their zonation patterns of both algae and animals, which can be expected to greatly affect food availability to consumers at different height levels on the shore. We tested the hypothesis that consumers would feed on the most abundant suitable food source in their surroundings. In total 36 species/taxa of common primary producers and consumers were sampled for stable isotope analyses from a sheltered fucoid shore at Hvassahraun in south-western Iceland. A selection of these species was also collected seasonally and from different height levels. Feeding experiments, field observations and gut analyses were also conducted. Our results were in good overall agreement with pre-existing knowledge of trophic relationships in the rocky intertidal. Consumers often appeared to be assimilating carbon and nitrogen from the most common diet in their immediate surroundings. The predator Nucella lapillus was thus feeding on different prey at different height levels in accordance with different densities of prey species. When tested in the laboratory, individuals taken from low on the shore would ignore the gastropod Littorina obtusata, uncommon at that height level, even when starved, while individuals from mid-shore readily ate the gastropod. This indicated that some kind of learned behaviour was involved. There were, however, important exceptions, most noteworthy the relatively small contribution to herbivores, both slow moving (the gastropod L. obtusata) and fast moving (the isopod Idotea granulosa and the amphipod Gammarus obtusatus) of the dominant alga at this site, Ascophyllum nodosum. The recent colonizer Fucus serratus seemed to be favoured. Selective feeding was indicated both by isotope signatures as well as by results of feeding experiments. Seasonal migrations of both slow and fast moving species could partly explain patterns observed.

The molecular dimension of microbial species: 1. Ecological distinctions among, and homogeneity within, putative ecotypes of Synechococcus inhabiting the cyanobacterial mat of Mushroom Spring, Yellowstone National Park

PubMed Central

Becraft, Eric D.; Wood, Jason M.; Rusch, Douglas B.; Kühl, Michael; Jensen, Sheila I.; Bryant, Donald A.; Roberts, David W.; Cohan, Frederick M.; Ward, David M.

2015-01-01

Based on the Stable Ecotype Model, evolution leads to the divergence of ecologically distinct populations (e.g., with different niches and/or behaviors) of ecologically interchangeable membership. In this study, pyrosequencing was used to provide deep sequence coverage of Synechococcus psaA genes and transcripts over a large number of habitat types in the Mushroom Spring microbial mat. Putative ecological species [putative ecotypes (PEs)], which were predicted by an evolutionary simulation based on the Stable Ecotype Model (Ecotype Simulation), exhibited distinct distributions relative to temperature-defined positions in the effluent channel and vertical position in the upper 1 mm-thick mat layer. Importantly, in most cases variants predicted to belong to the same PE formed unique clusters relative to temperature and depth in the mat in canonical correspondence analysis, supporting the hypothesis that while the PEs are ecologically distinct, the members of each ecotype are ecologically homogeneous. PEs responded differently to experimental perturbations of temperature and light, but the genetic variation within each PE was maintained as the relative abundances of PEs changed, further indicating that each population responded as a set of ecologically interchangeable individuals. Compared to PEs that predominate deeper within the mat photic zone, the timing of transcript abundances for selected genes differed for PEs that predominate in microenvironments closer to upper surface of the mat with spatiotemporal differences in light and O2 concentration. All of these findings are consistent with the hypotheses that Synechococcus species in hot spring mats are sets of ecologically interchangeable individuals that are differently adapted, that these adaptations control their distributions, and that the resulting distributions constrain the activities of the species in space and time. PMID:26157420

Trophic specialization and morphological divergence between two sympatric species in Lake Catemaco, Mexico.

PubMed

Ornelas-García, Claudia Patricia; Córdova-Tapia, Fernando; Zambrano, Luis; Bermúdez-González, María Pamela; Mercado-Silva, Norman; Mendoza-Garfias, Berenit; Bautista, Amando

2018-05-01

The association of morphological divergence with ecological segregation among closely related species could be considered as a signal of divergent selection in ecological speciation processes. Environmental signals such as diet can trigger phenotypic evolution, making polymorphic species valuable systems for studying the evolution of trophic-related traits. The main goal of this study was to analyze the association between morphological differences in trophic-related traits and ecological divergence in two sympatric species, Astyanax aeneus and A. caballeroi, inhabiting Lake Catemaco, Mexico. The trophic differences of a total of 70 individuals (35 A. aeneus and 35 A. caballeroi ) were examined using stable isotopes and gut content analysis; a subset of the sample was used to characterize six trophic and six ecomorphological variables. In our results, we recovered significant differences between both species in the values of stable isotopes, with higher values of δ 15 N for A. caballeroi than for A. aeneus . Gut content results were consistent with the stable isotope data, with a higher proportion of invertebrates in A. caballeroi (a consumption of invertebrates ten times higher than that of A. aeneus , which in turn consumed three times more vegetal material than A. caballeroi ). Finally, we found significant relationship between ecomorphology and stable isotopes ( r  = .24, p  < .01), hence, head length, preorbital length, eye diameter, and δ 15 N were all positively correlated; these characteristics correspond to A. caballeroi . While longer gut and gill rakers, deeper bodies, and vegetal material consumption were positively correlated and corresponded to A. aeneus . Our results are consistent with the hypothesis that morphological divergence in trophic-related traits could be associated with niche partitioning, allowing the coexistence of closely related species and reducing interspecific competition.

Temporal stability and change in the social call repertoire of migrating humpback whales.

PubMed

Rekdahl, Melinda L; Dunlop, Rebecca A; Noad, Michael J; Goldizen, Anne W

2013-03-01

Quantifying the stability of a species vocal repertoire is fundamental for further investigations into repertoire function and geographic variation. Changes to the repertoire of sounds used in the song displays of male humpback whales have been well studied. In contrast, little is known about the stability of this species' non-song vocal calls. The stability of the social call repertoire of east Australian humpback whales was investigated from 1997, 2003-2004, and 2008. Out of 46 qualitatively defined call types, 19 were classified as "song-unit calls" that tended to change with the song, and 15 were "inconsistent" and only found in one or two years. Twelve call types were "stable" and present in all years and were commonly produced (64.2% of calls). Stable calls tended to vary in some of the measured call parameters but there was no clear trend between years. This result could indicate that minor changes to calls are not permanent, but reflect individual differences in call production or the graded nature of calls within different social environments. This research has clearly identified stable calls in the call repertoire of humpback whales and while their function is not well understood, their stability suggests an important role in social interactions.

ASE extraction method for simultaneous carbon and nitrogen stable isotope analysis in soft tissues of aquatic organisms.

PubMed

Bodin, Nathalie; Budzinski, Hélène; Le Ménach, Karyn; Tapie, Nathalie

2009-06-08

Since lipids are depleted in 13C relative to proteins and carbohydrates, variations in lipid composition among species and within individuals significantly influence delta13C and may result in misleading ecological interpretations. Whereas lipid extraction before IRMS analysis constitutes a way of stable isotope result lipid-normalisation, such a procedure was given up because of the un-controlled effects of the methods used (i.e., "Bligh & Dyer", Soxhlet, etc.) on delta15N. The aim of this work was to develop a simple, rapid and efficient lipid extraction method allowing for simultaneous C and N stable isotope analysis in the biological soft tissues of aquatic organisms. The goal was to be free from the lipid influence on delta13C values without interfering with delta15N values. For that purpose, the modern automated pressurized liquid extraction technique ASE (accelerated solvent extraction) was selected. Eel muscles representative of a broad range of fat contents were extracted via ASE by using different semi-polar solvents (100% dichloromethane and 80% n-hexane/20% acetone) and by operating at different temperature (ambient temperature and 100 degrees C) and pressure (750 and 1900 psi) conditions. The results were discussed in terms of lipid extraction efficiency as well as delta13C and delta15N variability.

Individual Differences in Exercise Behavior: Stability and Change in Genetic and Environmental Determinants From Age 7 to 18.

PubMed

Huppertz, Charlotte; Bartels, Meike; de Zeeuw, Eveline L; van Beijsterveldt, Catharina E M; Hudziak, James J; Willemsen, Gonneke; Boomsma, Dorret I; de Geus, Eco J C

2016-09-01

Exercise behavior during leisure time is a major source of health-promoting physical activity and moderately tracks across childhood and adolescence. This study aims to investigate the absolute and relative contribution of genes and the environment to variance in exercise behavior from age 7 to 18, and to elucidate the stability and change of genetic and shared environmental factors that underlie this behavior. The Netherlands Twin Register collected data on exercise behavior in twins aged approximately 7, 10, 12, 14, 16 and 18 years (N = 27,332 twins; 48 % males; 47 % with longitudinal assessments). Three exercise categories (low, middle, high) were analyzed by means of liability threshold models. First, a univariate model was fitted using the largest available cross-sectional dataset with linear and quadratic effects of age as modifiers on the means and variance components. Second, a simplex model was fitted on the longitudinal dataset. Heritability was low in 7-year-olds (14 % in males and 12 % in females), but gradually increased up to age 18 (79 % in males and 49 % in females), whereas the initially substantial relative influence of the shared environment decreased with age (from 80 to 4 % in males and from 80 to 19 % in females). This decrease was due to a large increase in the genetic variance. The longitudinal model showed the genetic effects in males to be largely stable and to accumulate from childhood to late adolescence, whereas in females, they were marked by both transmission and innovation at all ages. The shared environmental effects tended to be less stable in both males and females. In sum, the clear age-moderation of exercise behavior implies that family-based interventions might be useful to increase this behavior in children, whereas individual-based interventions might be better suited for adolescents. We showed that some determinants of individual differences in exercise behavior are stable across childhood and youth, whereas others come into play at specific ages. In view of the many benefits of regular exercise, identifying these determinants at specific ages should be a public health priority.

Tolerant indirect reciprocity can boost social welfare through solidarity with unconditional cooperators in private monitoring.

PubMed

Okada, Isamu; Sasaki, Tatsuya; Nakai, Yutaka

2017-08-29

Indirect reciprocity is an important mechanism for resolving social dilemmas. Previous studies explore several types of assessment rules that are evolutionarily stable for keeping cooperation regimes. However, little is known about the effects of private information on social systems. Most indirect reciprocity studies assume public monitoring in which individuals share a single assessment for each individual. Here, we consider a private monitoring system that loosens such an unnatural assumption. We explore the stable norms in the private system using an individual-based simulation. We have three main findings. First, narrow and unstable cooperation: cooperation in private monitoring becomes unstable and the restricted norms cannot maintain cooperative regimes while they can in public monitoring. Second, stable coexistence of discriminators and unconditional cooperators: under private monitoring, unconditional cooperation can play a role in keeping a high level of cooperation in tolerant norm situations. Finally, Pareto improvement: private monitoring can achieve a higher cooperation rate than does public monitoring.

Mind your errors: evidence for a neural mechanism linking growth mind-set to adaptive posterror adjustments.

PubMed

Moser, Jason S; Schroder, Hans S; Heeter, Carrie; Moran, Tim P; Lee, Yu-Hao

2011-12-01

How well people bounce back from mistakes depends on their beliefs about learning and intelligence. For individuals with a growth mind-set, who believe intelligence develops through effort, mistakes are seen as opportunities to learn and improve. For individuals with a fixed mind-set, who believe intelligence is a stable characteristic, mistakes indicate lack of ability. We examined performance-monitoring event-related potentials (ERPs) to probe the neural mechanisms underlying these different reactions to mistakes. Findings revealed that a growth mind-set was associated with enhancement of the error positivity component (Pe), which reflects awareness of and allocation of attention to mistakes. More growth-minded individuals also showed superior accuracy after mistakes compared with individuals endorsing a more fixed mind-set. It is critical to note that Pe amplitude mediated the relationship between mind-set and posterror accuracy. These results suggest that neural mechanisms indexing on-line awareness of and attention to mistakes are intimately involved in growth-minded individuals' ability to rebound from mistakes.

Stable structures of coalitions in competitive and altruistic military teams

NASA Astrophysics Data System (ADS)

Aurangzeb, M.; Mikulski, D.; Hudas, G.; Lewis, F. L.; Gu, Edward

2013-05-01

In heterogeneous battlefield teams, the balance between team and individual objectives forms the basis for the internal topological structure of teams. The stability of team structure is studied by presenting a graphical coalitional game (GCG) with Positional Advantage (PA). PA is Shapley value strengthened by the Axioms of value. The notion of team and individual objectives is studied by defining altruistic and competitive contribution made by an individual; altruistic and competitive contributions made by an agent are components of its total or marginal contribution. Moreover, the paper examines dynamic team effects by defining three online sequential decision games based on marginal, competitive and altruistic contributions of the individuals towards team. The stable graphs under these sequential decision games are studied and found to be structurally connected, complete, or tree respectively.

Ability, Experience, and Task Difficulty Predictors of Task Performance

DTIC Science & Technology

1987-08-01

Per:or::o.ance :2. ;:>E~ SONAi . :..U7H0R(S) :ance, C. ~., Eedg~, ŗa. TYPE OF ?I.!:?OR"t" 39 ::s :. ~., & A1 ley, W. ~- 1130. ":"tM€ CO VERSO 114...haracteristics and stable individual differences determine behavior (e . g ., James & White, 1983; Kozlowski & Hults, 1986). Both intrasituational and...documented (e . g ., Mullins, Earles, & Ree, 1981 ) . ASVAB aptitude indices (Ais ), of which there are four (Mechanical, Administrative, General

Coping with Uncertainty: Woodpecker Finches (Cactospiza pallida) from an Unpredictable Habitat Are More Flexible than Birds from a Stable Habitat

PubMed Central

Tebbich, Sabine; Teschke, Irmgard

2014-01-01

Behavioural flexibility is thought to be a major factor in evolution. It may facilitate the discovery and exploitation of new resources, which in turn may expose populations to novel selective forces and facilitate adaptive radiation. Darwin's finches are a textbook example of adaptive radiation. They are fast learners and show a range of unusual foraging techniques, probably as a result of their flexibility. In this study we aimed to test whether variability of the environment is correlated with flexibility. We compared woodpecker finches from a dry area (hereafter, Arid Zone), where food availability is variable, with individuals from a cloud forest (hereafter, Scalesia zone) where food abundance is stable. As parameters for flexibility, we measured neophilia and neophobia, which are two aspects of reaction to novelty, reversal learning and problem-solving. We found no differences in performance on a problem-solving task but, in line with our prediction, individuals from the Arid Zone were significantly faster reversal learners and more neophilic than their conspecifics from the Scalesia zone. The latter result supports the notion that environmental variability drives flexibility. In contrast to our prediction, Arid Zone birds were even more neophobic than birds from the Scalesia Zone. The latter result could be the consequence of differences in predation pressure between the two vegetation zones. PMID:24638107

Group size, individual role differentiation and effectiveness of cooperation in a homogeneous group of hunters

PubMed Central

Escobedo, R.; Muro, C.; Spector, L.; Coppinger, R. P.

2014-01-01

The emergence of cooperation in wolf-pack hunting is studied using a simple, homogeneous, particle-based computational model. Wolves and prey are modelled as particles that interact through attractive and repulsive forces. Realistic patterns of wolf aggregation readily emerge in numerical simulations, even though the model includes no explicit wolf–wolf attractive forces, showing that the form of cooperation needed for wolf-pack hunting can take place even among strangers. Simulations are used to obtain the stationary states and equilibria of the wolves and prey system and to characterize their stability. Different geometric configurations for different pack sizes arise. In small packs, the stable configuration is a regular polygon centred on the prey, while in large packs, individual behavioural differentiation occurs and induces the emergence of complex behavioural patterns between privileged positions. Stable configurations of large wolf-packs include travelling and rotating formations, periodic oscillatory behaviours and chaotic group behaviours. These findings suggest a possible mechanism by which larger pack sizes can trigger collective behaviours that lead to the reduction and loss of group hunting effectiveness, thus explaining the observed tendency of hunting success to peak at small pack sizes. They also explain how seemingly complex collective behaviours can emerge from simple rules, among agents that need not have significant cognitive skills or social organization. PMID:24694897

Modulation of Reward-Related Neural Activation on Sensation Seeking across Development

PubMed Central

Hawes, Samuel W.; Chahal, Rajpreet; Hallquist, Michael N.; Paulsen, David J.; Geier, Charles F.; Luna, Beatriz

2017-01-01

Sensation seeking is a personality construct associated with an increased propensity for engaging in risk-taking. Associations with deleterious outcomes ranging from mental health impairments to increased mortality rates highlight important public health concerns related to this construct. Although some have suggested that increased neural responsivity to reward within the ventral striatum (e.g., nucleus accumbens) may drive sensation seeking behaviors, few studies have examined the neural mechanisms associated with stable individual differences in sensation seeking across development. To address this issue, the current study used functional magnetic resonance imaging to examine the association between neural responding to reward and stable patterns of sensation seeking across a three-year follow-up period among healthy adolescents and young adults (N = 139). Results indicated that during early adolescence (~ages 10–12), increased reactivity to reward within the nucleus accumbens (NAcc) was associated with lower levels of sensation seeking across a three-year follow-up. In middle adolescence (~ages 12–16), there was no evidence of a relationship between NAcc reactivity and sensation seeking. However, during the transition from late adolescence into adulthood (~ages 17–25), heightened reward-related reactivity in the NAcc was linked to increased sensation seeking. Findings suggest that the neural mechanisms underlying individual differences in trait-like levels of sensation seeking change from early to late adolescence. PMID:27956207

Reconstructing diet in Napoleon's Grand Army using stable carbon and nitrogen isotope analysis.

PubMed

Holder, Sammantha; Dupras, Tosha L; Jankauskas, Rimantas; Williams, Lana; Schultz, John

2017-05-01

Historical evidence has provided information regarding disease and mortality in Napoleon Bonaparte's Grand Army, but dietary information beyond individual soldier accounts remains scarce. The purpose of this research is to reconstruct the diets of Napoleon's multiethnic army who were associated with the Russian Campaign of 1812. We conducted stable carbon and nitrogen isotope ratio analysis on femoral bone collagen of 78 individuals recovered from a salvage excavation at the mass gravesite of Šiaurės miestelis in Vilnius, Lithuania. These individuals were later discovered to be Napoleonic soldiers and camp followers who participated in the 1812 Russian Campaign. Stable carbon isotope ratios range from -19.2‰ to -11.8‰, with a mean of -17.8‰ ± 1.5‰ (1 σ). Stable nitrogen isotope ratios range from 7.1‰ to 13.6‰, with a mean of 10.5‰ ± 1.4‰ (1 σ). Both δ 13 C and δ 15 N values show a wide range of variation. Stable isotope data indicate considerable dietary variation in this population associated with a multiethnic and socially stratified military population. Diets ranged from predominantly C 3 -based to predominantly C 4 -based, with varying inputs of terrestrial, freshwater, and marine animal protein. Comparison with other European populations further denotes the exceptional range of dietary variation of soldiers and camp followers in Napoleon's army. © 2017 Wiley Periodicals, Inc.

Emotional Granularity Effects on Event-Related Brain Potentials during Affective Picture Processing.

PubMed

Lee, Ja Y; Lindquist, Kristen A; Nam, Chang S

2017-01-01

There is debate about whether emotional granularity , the tendency to label emotions in a nuanced and specific manner, is merely a product of labeling abilities, or a systematic difference in the experience of emotion during emotionally evocative events. According to the Conceptual Act Theory of Emotion (CAT) (Barrett, 2006), emotional granularity is due to the latter and is a product of on-going temporal differences in how individuals categorize and thus make meaning of their affective states. To address this question, the present study investigated the effects of individual differences in emotional granularity on electroencephalography-based brain activity during the experience of emotion in response to affective images. Event-related potentials (ERP) and event-related desynchronization and synchronization (ERD/ERS) analysis techniques were used. We found that ERP responses during the very early (60-90 ms), middle (270-300 ms), and later (540-570 ms) moments of stimulus presentation were associated with individuals' level of granularity. We also observed that highly granular individuals, compared to lowly granular individuals, exhibited relatively stable desynchronization of alpha power (8-12 Hz) and synchronization of gamma power (30-50 Hz) during the 3 s of stimulus presentation. Overall, our results suggest that emotional granularity is related to differences in neural processing throughout emotional experiences and that high granularity could be associated with access to executive control resources and a more habitual processing of affective stimuli, or a kind of "emotional complexity." Implications for models of emotion are also discussed.

Radar signal categorization using a neural network

NASA Technical Reports Server (NTRS)

Anderson, James A.; Gately, Michael T.; Penz, P. Andrew; Collins, Dean R.

1991-01-01

Neural networks were used to analyze a complex simulated radar environment which contains noisy radar pulses generated by many different emitters. The neural network used is an energy minimizing network (the BSB model) which forms energy minima - attractors in the network dynamical system - based on learned input data. The system first determines how many emitters are present (the deinterleaving problem). Pulses from individual simulated emitters give rise to separate stable attractors in the network. Once individual emitters are characterized, it is possible to make tentative identifications of them based on their observed parameters. As a test of this idea, a neural network was used to form a small data base that potentially could make emitter identifications.

Is the Rational Addiction model inherently impossible to estimate?

PubMed

Laporte, Audrey; Dass, Adrian Rohit; Ferguson, Brian S

2017-07-01

The Rational Addiction (RA) model is increasingly often estimated using individual level panel data with mixed results; in particular, with regard to the implied rate of time discount. This paper suggests that the odd values of the rate of discount frequently found in the literature may in fact be a consequence of the saddle-point dynamics associated with individual level inter-temporal optimization problems. We report the results of Monte Carlo experiments estimating RA-type difference equations that seem to suggest the possibility that the presence of both a stable and an unstable root in the dynamic process may create serious problems for the estimation of RA equations. Copyright © 2016 Elsevier B.V. All rights reserved.

Behavioral and neuronal determinants of negative reciprocity in the ultimatum game.

PubMed

Kaltwasser, Laura; Hildebrandt, Andrea; Wilhelm, Oliver; Sommer, Werner

2016-10-01

The rejection of unfair offers in the ultimatum game (UG) indicates negative reciprocity. The model of strong reciprocity claims that negative reciprocity reflects prosociality because the rejecting individual is sacrificing resources in order to punish unfair behavior. However, a recent study found that the rejection rate of unfair offers is linked to assertiveness (status defense model). To pursue the question what drives negative reciprocity, the present study investigated individual differences in the rejection of unfair offers along with their behavioral and neuronal determinants. We measured fairness preferences and event-related potentials (ERP) in 200 healthy participants playing a computerized version of the UG with pictures of unfair and fair proposers. Structural equation modeling (SEM) on the behavioral data corroborated both the strong reciprocity and the status defense models of human cooperation: Not only more prosocial but also more assertive individuals were more likely to show negative reciprocity by rejecting unfair offers. Experimental ERP results confirmed the feedback negativity (FN) as a neural signature of fairness processing. Multilevel SEM of brain-behavior relationships revealed that negative reciprocity was significantly associated with individual differences in FN amplitudes in response to proposers. Our results confirm stable individual differences in fairness processing at the behavioral and neuronal level. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

The evolutionary psychology of left and right: costs and benefits of lateralization.

PubMed

Vallortigara, Giorgio

2006-09-01

Why do the left and right sides of the vertebrate brain play different functions? Having a lateralized brain, in which each hemisphere carries out different functions, is ubiquitous among vertebrates. The different specialization of the left and right side of the brain may increase brain efficiency--and some evidence for that is reported here. However, lateral biases due to brain lateralization (such as preferences in the use of a limb or, in animals with laterally placed eyes, of a visual hemifield) usually occur at the population level, with most individuals showing similar direction of bias. Individual brain efficiency does not require the alignment of lateralization in the population. Why then are not left--and right-type individuals equally common? Not only humans, but most vertebrates show a similar pattern. For instance, in the paper I report evidence that most toads, chickens, and fish react faster when a predator approaches from the left. I argue that invoking individual brain efficiency (lateralization may increase fitness), evolutionary chance or direct genetic mechanisms cannot explain this widespread pattern. Instead, using concepts from mathematical theory of games, I show that alignment of lateralization at the population level may arise as an "evolutionarily stable strategy" when individually asymmetrical organisms must coordinate their behavior with that of other asymmetrical organisms. Thus, the population structure of lateralization may result from genes specifying the direction of asymmetries which have been selected under "social" pressures.

Individual differences in personality traits reflect structural variance in specific brain regions.

PubMed

Gardini, Simona; Cloninger, C Robert; Venneri, Annalena

2009-06-30

Personality dimensions such as novelty seeking (NS), harm avoidance (HA), reward dependence (RD) and persistence (PER) are said to be heritable, stable across time and dependent on genetic and neurobiological factors. Recently a better understanding of the relationship between personality traits and brain structures/systems has become possible due to advances in neuroimaging techniques. This Magnetic Resonance Imaging (MRI) study investigated if individual differences in these personality traits reflected structural variance in specific brain regions. A large sample of eighty five young adult participants completed the Three-dimensional Personality Questionnaire (TPQ) and had their brain imaged with MRI. A voxel-based correlation analysis was carried out between individuals' personality trait scores and grey matter volume values extracted from 3D brain scans. NS correlated positively with grey matter volume in frontal and posterior cingulate regions. HA showed a negative correlation with grey matter volume in orbito-frontal, occipital and parietal structures. RD was negatively correlated with grey matter volume in the caudate nucleus and in the rectal frontal gyrus. PER showed a positive correlation with grey matter volume in the precuneus, paracentral lobule and parahippocampal gyrus. These results indicate that individual differences in the main personality dimensions of NS, HA, RD and PER, may reflect structural variance in specific brain areas.

The pain of a model in the personality of an onlooker: influence of state-reactivity and personality traits on embodied empathy for pain.

PubMed

Avenanti, Alessio; Minio-Paluello, Ilaria; Bufalari, Ilaria; Aglioti, Salvatore M

2009-01-01

The study of inter-individual differences at behavioural and neural levels represents a new avenue for neuroscience. The response to socio-emotional stimuli varies greatly across individuals. For example, identification with the feelings of a movie character may be total for some people or virtually absent for others. Inter-individual differences may reflect both the on-line effect (state) of the observed stimuli and more stable personal characteristics (trait). Here we show that somatomotor mirror responses when viewing others' pain are modulated by both state- and trait-differences in empathy. We recorded motor-evoked potentials (MEPs) induced by Transcranial Magnetic Stimulation (TMS) in healthy individuals observing needles penetrating a model's hand. We found a reduction of corticospinal excitability that was specific for the muscle that subjects observed being penetrated. This inhibition correlated with sensory qualities of the pain ascribed to the model. Moreover, it was greater in subjects with high trait-cognitive empathy and lower in subjects with high trait-personal distress and in those with high aversion for the observed movies. Results indicate that somatomotor responses to others' pain are influenced by specific onlookers' personality traits and self-oriented emotional reactions. Our findings suggest that multiple distinct mechanisms shape mirror mapping of others' pain.

Patterns of Change in Collaboration Are Associated with Baseline Characteristics and Predict Outcome and Dropout Rates in Treatment of Multi-Problem Families. A Validation Study

PubMed Central

Bachler, Egon; Fruehmann, Alexander; Bachler, Herbert; Aas, Benjamin; Nickel, Marius; Schiepek, Guenter K.

2017-01-01

Objective: The present study validates the Multi-Problem Family (MPF)-Collaboration Scale), which measures the progress of goal directed collaboration of patients in the treatment of families with MPF and its relation to drop-out rates and treatment outcome. Method: Naturalistic study of symptom and competence-related changes in children of ages 4–18 and their caregivers. Setting: Integrative, structural outreach family therapy. Measures: The data of five different groups of goal directed collaboration (deteriorating collaboration, stable low collaboration, stable medium collaboration, stable high collaboration, improving collaboration) were analyzed in their relation to treatment expectation, individual therapeutic goals (ITG), family adversity index, severity of problems and global assessment of a caregiver’s functioning, child, and relational aspects. Results: From N = 810 families, 20% displayed stable high collaboration (n = 162) and 21% had a pattern of improving collaboration. The families with stable high or improving collaboration rates achieved significantly more progress throughout therapy in terms of treatment outcome expectancy (d = 0.96; r = 0.43), reaching ITG (d = 1.17; r = 0.50), family adversities (d = 0.55; r = 0.26), and severity of psychiatric symptoms (d = 0.31; r = 0.15). Furthermore, families with stable high or improving collaboration maintained longer treatments and had a bigger chance of finishing the therapy as planned. The odds of having a stable low or deteriorating collaboration throughout treatment were significantly higher for subjects who started treatment with low treatment expectation or high family-related adversities. Conclusion: The positive outcomes of homebased interventions for multi-problem families are closely related to “stable high” and an “improving” collaboration as measured with the MPF-Collaboration Scale. Patients who fall into these groups have a high treatment outcome expectancy and reduce psychological stress. For therapeutic interventions with multi-problem families it seems beneficial to maintain a stable high collaboration or help the collaboration, e.g., by fostering treatment expectation. PMID:28785232

Macrophytes shape trophic niche variation among generalist fishes.

PubMed

Vejříková, Ivana; Eloranta, Antti P; 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 food-web structures in lake ecosystems.

Bistability of Evolutionary Stable Vaccination Strategies in the Reinfection SIRI Model.

PubMed

Martins, José; Pinto, Alberto

2017-04-01

We use the reinfection SIRI epidemiological model to analyze the impact of education programs and vaccine scares on individuals decisions to vaccinate or not. The presence of the reinfection provokes the novelty of the existence of three Nash equilibria for the same level of the morbidity relative risk instead of a single Nash equilibrium as occurs in the SIR model studied by Bauch and Earn (PNAS 101:13391-13394, 2004). The existence of three Nash equilibria, with two of them being evolutionary stable, introduces two scenarios with relevant and opposite features for the same level of the morbidity relative risk: the low-vaccination scenario corresponding to the evolutionary stable vaccination strategy, where individuals will vaccinate with a low probability; and the high-vaccination scenario corresponding to the evolutionary stable vaccination strategy, where individuals will vaccinate with a high probability. We introduce the evolutionary vaccination dynamics for the SIRI model and we prove that it is bistable. The bistability of the evolutionary dynamics indicates that the damage provoked by false scares on the vaccination perceived morbidity risks can be much higher and much more persistent than in the SIR model. Furthermore, the vaccination education programs to be efficient they need to implement a mechanism to suddenly increase the vaccination coverage level.

Why is intelligence associated with stability of happiness?

PubMed

Kanazawa, Satoshi

2014-08-01

In the National Child Development Study, life-course variability in happiness over 18 years was significantly negatively associated with its mean level (happier individuals were more stable in their happiness, and it was not due to the ceiling effect), as well as childhood general intelligence and all Big Five personality factors (except for Agreeableness). In a multiple regression analysis, childhood general intelligence was the strongest predictor of life-course variability in life satisfaction, stronger than all Big Five personality factors, including Emotional stability. More intelligent individuals were significantly more stable in their happiness, and it was not entirely because: (1) they were more educated and wealthier (even though they were); (2) they were healthier (even though they were); (3) they were more stable in their marital status (even though they were); (4) they were happier (even though they were); (5) they were better able to assess their own happiness accurately (even though they were); or (6) they were better able to recall their previous responses more accurately or they were more honest in their survey responses (even though they were both). While I could exclude all of these alternative explanations, it ultimately remained unclear why more intelligent individuals were more stable in their happiness. © 2013 The British Psychological Society.

Correlates of individual differences in compensatory nicotine self-administration in rats following a decrease in nicotine unit dose

PubMed Central

Harris, Andrew C.; Pentel, Paul R.; LeSage, Mark G.

2013-01-01

Rationale The ability of tobacco harm reduction strategies to produce significant reductions in toxin exposure is limited by compensatory increases in smoking behavior. Characterizing factors contributing to the marked individual variability in compensation may be useful for understanding this phenomenon and assessing the feasibility of harm reduction interventions. Objective To use an animal model of human compensatory smoking that involves a decrease in unit dose supporting nicotine self-administration (NSA) to examine potential contributors to individual differences in compensation. Methods Rats were trained for NSA during daily 23 hr sessions at a unit dose of 0.06 mg/kg/inf until responding was stable. The unit dose was then reduced to 0.03 mg/kg/inf for at least 10 sessions. Following reacquisition of NSA at the training dose and extinction, single-dose nicotine pharmacokinetic parameters were determined. Results Decreases in nicotine intake following dose reduction were proportionally less than the decrease in unit dose, indicating partial compensation. Compensatory increases in infusion rates were observed across the course of the 23 hr sessions. The magnitude of compensation differed considerably between rats. Rats exhibiting the highest baseline infusion rates exhibited the lowest levels of compensation. Nicotine pharmacokinetic parameters were not significantly correlated with compensation. Infusion rates immediately returned to pre-reduction levels when baseline conditions were restored. Conclusions These findings provide initial insights into correlates of individual differences in compensation following a reduction in nicotine unit dose. The present assay may be useful for characterizing mechanisms and potential consequences of the marked individual differences in compensatory smoking observed in humans. PMID:19475400

Individual differences in learning and transfer: stable tendencies for learning exemplars versus abstracting rules.

PubMed

McDaniel, Mark A; Cahill, Michael J; Robbins, Mathew; Wiener, Chelsea

2014-04-01

We hypothesize that during training some learners may focus on acquiring the particular exemplars and responses associated with the exemplars (termed exemplar learners), whereas other learners attempt to abstract underlying regularities reflected in the particular exemplars linked to an appropriate response (termed rule learners). Supporting this distinction, after training (on a function-learning task), participants displayed an extrapolation profile reflecting either acquisition of the trained cue-criterion associations (exemplar learners) or abstraction of the function rule (rule learners; Studies 1a and 1b). Further, working memory capacity (measured by operation span [Ospan]) was associated with the tendency to rely on rule versus exemplar processes. Studies 1c and 2 examined the persistence of these learning tendencies on several categorization tasks. Study 1c showed that rule learners were more likely than exemplar learners (indexed a priori by extrapolation profiles) to resist using idiosyncratic features (exemplar similarity) in generalization (transfer) of the trained category. Study 2 showed that the rule learners but not the exemplar learners performed well on a novel categorization task (transfer) after training on an abstract coherent category. These patterns suggest that in complex conceptual tasks, (a) individuals tend to either focus on exemplars during learning or on extracting some abstraction of the concept, (b) this tendency might be a relatively stable characteristic of the individual, and (c) transfer patterns are determined by that tendency.

The stability and predictors of peer group deviance in university students.

PubMed

Kendler, Kenneth S; Myers, John; Dick, Danielle

2015-09-01

Peer group deviance (PGD) is strongly associated with current and future externalizing behaviors. Debate remains about the degree to which this association arises from social selection. The first year of university constitutes a social experiment in which most individuals leave their home environment and recreate for themselves a new peer group. PGD was measured in newly arrived university students and then 6 and 18 months later. Other personality and family traits were also assessed. PGD reported for high school friends at the start of university and university friends 6 months later were substantially correlated (+0.60). This correlation was only slightly diminished if restricted to students whose home was greater than 50 miles from the university. PGD was strongly predicted across three cohorts by male sex (+), extraversion (+), conscientiousness (-), a family history of alcohol use disorders (+) and depression (+), and religiosity (-).These predictors of PGD had a relatively stable impact over 18 months and, aside from sex, differed only modestly in males and females. As individuals change social groups from high school to university, the level of PGD remains relatively stable, suggesting that individuals play a strong role in selecting peer groups with consistent characteristics. PGD is also predicted cross-sectionally and longitudinally by personality, family background and religiosity. Our results suggest that the association between personal and peer deviance is due at least in part to the effects of social selection.

Individual Differences in Learning and Transfer: Stable Tendencies for Learning Exemplars versus Abstracting Rules

PubMed Central

McDaniel, Mark A.; Cahill, Michael J.; Robbins, Mathew; Wiener, Chelsea

2013-01-01

We hypothesize that during training some learners may focus on acquiring the particular exemplars and responses associated with the exemplars (termed exemplar learners), whereas other learners attempt to abstract underlying regularities reflected in the particular exemplars linked to an appropriate response (termed rule learners). Supporting this distinction, after training (on a function-learning task), participants either displayed an extrapolation profile reflecting acquisition of the trained cue-criterion associations (exemplar learners) or abstraction of the function rule (rule learners; Studies 1a and 1b). Further, working memory capacity (measured by Ospan) was associated with the tendency to rely on rule versus exemplar processes. Studies 1c and 2 examined the persistence of these learning tendencies on several categorization tasks. Study 1c showed that rule learners were more likely than exemplar learners (indexed a priori by extrapolation profiles) to resist using idiosyncratic features (exemplar similarity) in generalization (transfer) of the trained category. Study 2 showed that the rule learners but not the exemplar learners performed well on a novel categorization task (transfer) after training on an abstract coherent category. These patterns suggest that in complex conceptual tasks, (a) individuals tend to either focus on exemplars during learning or on extracting some abstraction of the concept, (b) this tendency might be a relatively stable characteristic of the individual, and (c) transfer patterns are determined by that tendency. PMID:23750912

The evolution of cooperation by negotiation in a noisy world.

PubMed

Ito, K; McNamara, J M; Yamauchi, A; Higginson, A D

2017-03-01

Cooperative interactions among individuals are ubiquitous despite the possibility of exploitation by selfish free riders. One mechanism that may promote cooperation is 'negotiation': individuals altering their behaviour in response to the behaviour of others. Negotiating individuals decide their actions through a recursive process of reciprocal observation, thereby reducing the possibility of free riding. Evolutionary games with response rules have shown that infinitely many forms of the rule can be evolutionarily stable simultaneously, unless there is variation in individual quality. This potentially restricts the conditions under which negotiation could maintain cooperation. Organisms interact with one another in a noisy world in which cooperative effort and the assessment of effort may be subject to error. Here, we show that such noise can make the number of evolutionarily stable rules finite, even without quality variation, and so noise could help maintain cooperative behaviour. We show that the curvature of the benefit function is the key factor determining whether individuals invest more or less as their partner's investment increases, investing less when the benefit to investment has diminishing returns. If the benefits of low investment are very small then behavioural flexibility tends to promote cooperation, because negotiation enables cooperators to reach large benefits. Under some conditions, this leads to a repeating cycle in which cooperative behaviour rises and falls over time, which may explain between-population differences in cooperative behaviour. In other conditions, negotiation leads to extremely high levels of cooperative behaviour, suggesting that behavioural flexibility could facilitate the evolution of eusociality in the absence of high relatedness. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Reexamining the Efficacy and Value of Percutaneous Coronary Intervention for Patients With Stable Ischemic Heart Disease

PubMed Central

Weintraub, William S.; Boden, William E.

2017-01-01

Percutaneous coronary intervention (PCI) continues to be performed frequently for patients with stable ischemic heart disease, despite uncertain efficacy. Individual randomized trial data and meta-analyses have not demonstrated that PCI in addition to optimal medical therapy reduces the incidence of death or myocardial infarction in patients with stable disease. The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) Trial did not show benefit for cardiovascular outcomes or mortality but did find a modest improvement in quality of life that did not persist at 3 years. Long-term follow-up from COURAGE (up to 15 years) found no differences in mortality, consistent with other published literature. How PCI could reduce long-term mortality or prevent myocardial infarction is not clear because sites of future plaque rupture leading to myocardial infarction are unpredictable and PCI can only treat localized anatomic segments of obstructive atherosclerosis. In addition, PCI is expensive, and the value to society of PCI for stable disease has not been demonstrated. The ISCHEMIA trial will assess the role of PCI for stable ischemic heart disease using newer technology and in patients with greater ischemic burden than in COURAGE. After nearly a decade, the COURAGE trial and other studies have given us pause to critically reexamine the role of PCI for patients with stable ischemic heart disease. Until further research can show that PCI can reduce cardiovascular events in these patients, a first-line strategy of optimal medical therapy is known to be safe, effective, and noninferior to PCI, and our practice should more closely follow this strategy. PMID:27380178

Health status, quality of life, residential stability, substance use, and health care utilization among adults applying to a supportive housing program.

PubMed

Hwang, Stephen W; Gogosis, Evie; Chambers, Catharine; Dunn, James R; Hoch, Jeffrey S; Aubry, Tim

2011-12-01

Supportive housing, defined as subsidized housing in conjunction with site-based social services, may help improve the health and residential stability of highly disadvantaged individuals. This study examined changes in health status, quality of life, substance use, health care utilization, and residential stability among 112 homeless and vulnerably housed individuals who applied to a supportive housing program in Toronto, Canada, from December 2005 to June 2007. Follow-up interviews were conducted every 6 months for 18 months. Comparisons were made between individuals who were accepted into the program (intervention) and those who were wait-listed (usual care) using repeated-measures analyses. Individuals who were accepted into the housing program experienced significantly greater improvements in satisfaction with living situation compared with individuals in the usual care group (time, F(3,3,261) = 47.68, p < 0.01; group × time, F(3,3,261) = 14.60, p < 0.01). There were no significant differences in other quality of life measures, health status, health care utilization, or substance use between the two groups over time. Significant improvement in residential stability occurred over time, independent of assigned housing group (time, F(3,3,261) = 9.96, p < 0.01; group × time, F(3,3,261) = 1.74, p = 0.17). The ability to examine the effects of supportive housing on homeless individuals was limited by the small number of participants who were literally homeless at baseline and by the large number of participants who gained stable housing during the study period regardless of their assigned housing status. Nonetheless, this study shows that highly disadvantaged individuals with a high prevalence of poor physical and mental health and substance use can achieve stable housing.

Winter diets of immature green turtles (Chelonia mydas) on a northern feeding ground: integrating stomach contents and stable isotope analyses

USGS Publications Warehouse

Williams, Natalie C.; Bjorndal, Karen A.; Lamont, Margaret M.; Carthy, Raymond R.

2015-01-01

The foraging ecology and diet of the green turtle, Chelonia mydas, remain understudied, particularly in peripheral areas of its distribution. We assessed the diet of an aggregation of juvenile green turtles at the northern edge of its range during winter months using two approaches. Stomach content analyses provide a single time sample, and stable isotope analyses integrate diet over a several-month period. We evaluated diet consistency in prey choice over time by comparing the results of these two approaches. We examined stomach contents from 43 juvenile green turtles that died during cold stunning events in St. Joseph Bay, Florida, in 2008 and 2011. Stomach contents were evaluated for volume, dry mass, percent frequency of occurrence, and index of relative importance of individual diet items. Juvenile green turtles were omnivorous, feeding primarily on seagrasses and tunicates. Diet characterizations from stomach contents differed from those based on stable isotope analyses, indicating the turtles are not feeding consistently during winter months. Evaluation of diets during warm months is needed.

Evaluating stability and change in personality and depression.

PubMed

Santor, D A; Bagby, R M; Joffe, R T

1997-12-01

Critics have argued that personality factors believed to represent a vulnerability to depression are not stable and are therefore state dependent. However, conclusions regarding the stability of personality and the relation between personality and depression have been drawn (a) without differentiating relative stability among individual differences from absolute stability of change scores and (b) without explicitly modeling change in personality as a function of change in depression. The relation between neuroticism and depression was examined in a sample of depressed outpatients (N = 71) receiving a 5-week trial of pharmacotherapy. Measures of neuroticism and extraversion demonstrated both relative stability and absolute change, and changes in neuroticism and extraversion scores were modestly or not at all accounted for by changes in depression scores. Claims that personality scores are not stable and are state dependent must be reconsidered.

Development of personality disorder symptoms and the risk for partner violence.

PubMed

Ehrensaft, Miriam K; Cohen, Patricia; Johnson, Jeffrey G

2006-08-01

In a community sample (N = 543) followed over 20 years, the authors studied associations among childhood family violence exposure, personality disorder (PD) symptoms, and adult partner violence. PD symptoms (DSM-III-R Clusters A, B, and C) in early adulthood partially mediated the effect of earlier childhood risks on the odds of perpetrating partner violence. The authors tested whether stability of PD symptoms from adolescence to the early 20s differs for individuals who later perpetrated partner violence. Cluster A ("Odd/Eccentric") symptoms declined less with age among partner violent versus nonviolent men and women. Cluster B ("Dramatic/Erratic") symptoms were more stable through late adolescence in partner violent men, compared with nonviolent men and violent women. Cluster C ("Anxious") symptoms were most stable among partner violent men. Copyright 2006 APA, all rights reserved.

Does Early Mathematics Intervention Change the Processes Underlying Children’s Learning?

PubMed Central

Watts, Tyler W.; Clements, Douglas H.; Sarama, Julie; Wolfe, Christopher B.; Spitler, Mary Elaine; Bailey, Drew H.

2017-01-01

Early educational intervention effects typically fade in the years following treatment, and few studies have investigated why achievement impacts diminish over time. The current study tested the effects of a preschool mathematics intervention on two aspects of children’s mathematical development. We tested for separate effects of the intervention on “state” (occasion-specific) and “trait” (relatively stable) variability in mathematics achievement. Results indicated that, although the treatment had a large impact on state mathematics, the treatment had no effect on trait mathematics, or the aspect of mathematics achievement that influences stable individual differences in mathematics achievement over time. Results did suggest, however, that the intervention could affect the underlying processes in children’s mathematical development by inducing more transfer of knowledge immediately following the intervention for students in the treated group. PMID:29399243

Personality traits and ego-network dynamics

PubMed Central

Centellegher, Simone; López, Eduardo; Saramäki, Jari; Lepri, Bruno

2017-01-01

Strong and supportive social relationships are fundamental to our well-being. However, there are costs to their maintenance, resulting in a trade-off between quality and quantity, a typical strategy being to put a lot of effort on a few high-intensity relationships while maintaining larger numbers of less close relationships. It has also been shown that there are persistent individual differences in this pattern; some individuals allocate their efforts more uniformly across their networks, while others strongly focus on their closest relationships. Furthermore, some individuals maintain more stable networks than others. Here, we focus on how personality traits of individuals affect this picture, using mobile phone calls records and survey data from the Mobile Territorial Lab (MTL) study. In particular, we look at the relationship between personality traits and the (i) persistence of social signatures, namely the similarity of the social signature shape of an individual measured in different time intervals; (ii) the turnover in egocentric networks, that is, differences in the set of alters present at two consecutive temporal intervals; and (iii) the rank dynamics defined as the variation of alter rankings in egocentric networks in consecutive intervals. We observe that some traits have effects on the stability of the social signatures as well as network turnover and rank dynamics. As an example, individuals who score highly in the Openness to Experience trait tend to have higher levels of network turnover and larger alter rank variations. On broader terms, our study shows that personality traits clearly affect the ways in which individuals maintain their personal networks. PMID:28253333

Local Nash equilibrium in social networks.

PubMed

Zhang, Yichao; Aziz-Alaoui, M A; Bertelle, Cyrille; Guan, Jihong

2014-08-29

Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures.

Local Nash Equilibrium in Social Networks

PubMed Central

Zhang, Yichao; Aziz-Alaoui, M. A.; Bertelle, Cyrille; Guan, Jihong

2014-01-01

Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures. PMID:25169150

Local Nash Equilibrium in Social Networks

NASA Astrophysics Data System (ADS)

Zhang, Yichao; Aziz-Alaoui, M. A.; Bertelle, Cyrille; Guan, Jihong

2014-08-01

Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures.

The stability of individual patterns of autonomic responses to motion sickness stimulation

NASA Technical Reports Server (NTRS)

Cowings, Patricia S.; Toscano, William B.; Naifeh, Karen H.

1990-01-01

As part of a program to develop a treatment for motion sickness based on self-regulation of autonomic nervous system (ANS) activity, this study examined the stability of an individual's pattern of ANS responses to motion sickness stimulation on repeated occasions. Motion sickness symptoms were induced in 58 people during two rotating chair test. Physiological responses measured were heart rate, finger pulse volume, respiration rate, and skin conductance. Using standard scores, stability of responses of specific magnitudes across both tests is as examined. Correlational analyses, analysis of variance, and a components of variance analysis all revealed marked, but quite stable, individual differences in ANS responses to both mild and severe motion sickness. These findings confirm the prior observation that people are sufficiently unique in their ANS responses to motion sickness provocation to make it nesessary to individually tailor self-regulation training. Further, these data support the contention that individual ANS patterns are sufficiently consistent from test to test so as to serve as an objective indicator of individual motion sickness malaise levels.

Online analysis of chlorine stable isotopes in chlorinated ethylenes: an inter-laboratory study

NASA Astrophysics Data System (ADS)

Bernstein, Anat; Shouakar-Stash, Orfan; Hunkeler, Daniel; Sakaguchi-Söder, Kaori; Laskov, Christine; Aravena, Ramon; Elsner, Martin

2010-05-01

In the last decade, compound-specific stable isotopes analysis of groundwater pollutants became an important tool to identify different sources of the same pollutant and for tracking natural attenuating processes in the sub-surface. It has been shown that trends in the isotopic composition of the target compounds can shed light on in-situ processes that are otherwise difficult to track. Analytical methods of carbon, nitrogen and hydrogen were established and are by now frequently used for a variety of organic pollutants. Yet, the motivation of introducing analytical methods for new isotopes is emerging. This motivation is further enhanced, as advantages of using two or more stable isotopes for gaining better insight on degradation pathways are well accepted. One important element which demands the development of appropriate analytical methods is chlorine, which is found in various groups of organic pollutants, among them the chlorinated ethylenes. Chlorinated ethylenes are considered as high priority environmental pollutants, and the development of suitable chlorine isotope methods for this group of pollutants is highly desired. Ideally, stable isotope techniques should have the capability to determine the isotopic composition of and individual target compound in a non-pure mixture, without the requirement of a laborious off-line treatment. Indeed, in the last years two different concepts for on-line chlorine isotope analysis methods were introduced, by using either a standard quadrapole GC/MS (Sakaguchi-Söder et al., 2007) or by using a GC/IRMS (Shouakar-Stash et al., 2006). We present a comparison of the performances of two concepts, carried out in five different laboratories: Waterloo (GC/IRMS), Neuchâtel (GC/MS), Darmstadt (GC/MS), Tübingen (GC/MS) and Munich (GC/IRMS). This comparison was performed on pure trichloroethylene and dichloroethylene products of different manufactures, as well as trichloroethylene and dichloroethylene samples that were exposed to biodegradation. This study sets standards for further application of these techniques to distinguish sources and track degradation processes in the sub-surface.

Trophic Interactions in Louisiana Salt Marshes: Combining Stomach Content, Stable Isotope, and Fatty Acid Approaches

NASA Astrophysics Data System (ADS)

Lopez-Duarte, P. C.; Able, K.; Fodrie, J.; McCann, M. J.; Melara, S.; Noji, C.; Olin, J.; Pincin, J.; Plank, K.; Polito, M. J.; Jensen, O.

2016-02-01

Multiple studies conducted over five years since the 2010 Macondo oil spill in the Gulf of Mexico indicate that oil impacts vary widely among taxonomic groups. For instance, fishes inhabiting the marsh surface show no clear differences in either community composition or population characteristics between oiled and unoiled sites, despite clear evidence of physiological impacts on individual fish. In contrast, marsh insects and spiders are sensitive to the effects of hydrocarbons. Both insects and spiders are components of the marsh food web and represent an important trophic link between marsh plants and higher trophic levels. Because differences in oil impacts throughout the marsh food web have the potential to significantly alter food webs and energy flow pathways and reduce food web resilience, our goal is to quantify differences in marsh food webs between oiled and unoiled sites to test the hypothesis that oiling has resulted in simpler and less resilient food webs. Diets and food web connections were quantified through a combination of stomach content, stable isotope, and fatty acid analysis. The combination of these three techniques provides a more robust approach to quantifying trophic relationships than any of these methods alone. Stomach content analysis provides a detailed snapshot of diets, while fatty acid and stable isotopes reflect diets averaged over weeks to months. Initial results focus on samples collected in May 2015 from a range of terrestrial and aquatic consumer species, including insects, mollusks, crustaceans, and piscivorous fishes.

Trophic level and macronutrient shift effects associated with the weaning process in the Postclassic Maya.

PubMed

Williams, Jocelyn S; White, Christine D; Longstaffe, Fred J

2005-12-01

The weaning process was investigated at two Maya sites dominated by Postclassic remains: Marco Gonzalez (100 BC-AD 1350) and San Pedro (1400-AD 1650), Belize. Bone collagen and bioapatite were analyzed from 67 individuals (n < or = 6 years = 15, n > 6 years = 52). Five isotopic measures were used to reconstruct diet and weaning: stable nitrogen- and carbon-isotope ratios in collagen, stable carbon- and oxygen-isotope ratios in bioapatite, and the difference in stable carbon-isotope values of coexisting collagen and bioapatite. Nitrogen-isotope ratios in infant collagen from both sites are distinct from adult females, indicating a trophic level effect. Collagen-to-bioapatite differences in infant bone from both sites are distinct from adult females, indicating a shift in macronutrients. Oxygen-isotope ratios in infant bioapatite from both sites are also distinct from adult females, indicating the consumption of breast milk. Among infants, carbon- and nitrogen-isotope ratios vary, indicating death during different stages in the weaning process. The ethnohistoric and paleopathological literature on the Maya indicate cessation of breast-feeding between ages 3-4 years. Isotopic data from Marco Gonzalez and San Pedro also indicate an average weaning age of 3-4 years. Based on various isotopic indicators, weaning likely began around age 12 months. This data set is not only important for understanding the weaning process during the Postclassic, but also demonstrates the use of collagen-to-bioapatite spacing as an indicator of macronutrient shifts associated with weaning. 2005 Wiley-Liss, Inc.

Aging-Resilient Associations between the Arcuate Fasciculus and Vocabulary Knowledge: Microstructure or Morphology?

PubMed Central

Vaden, Kenneth I.; Cute, Stephanie L.; Yeatman, Jason D.; Dougherty, Robert F.

2016-01-01

Vocabulary knowledge is one of the few cognitive functions that is relatively preserved in older adults, but the reasons for this relative preservation have not been well delineated. We tested the hypothesis that individual differences in vocabulary knowledge are influenced by arcuate fasciculus macrostructure (i.e., shape and volume) properties that remain stable during the aging process, rather than white matter microstructure that demonstrates age-related declines. Vocabulary was not associated with age compared to pronounced age-related declines in cognitive processing speed across 106 healthy adults (19.92–88.29 years) who participated in this neuroimaging experiment. Fractional anisotropy in the left arcuate fasciculus was significantly related to individual variability in vocabulary. This effect was present despite marked age-related differences in a T1-weighted/T2-weighted ratio (T1w/T2w) estimate of myelin that were observed throughout the left arcuate fasciculus and associated with age-related differences in cognitive processing speed. However, atypical patterns of arcuate fasciculus morphology or macrostructure were associated with decreased vocabulary knowledge. These results suggest that deterioration of tissue in the arcuate fasciculus occurs with normal aging, while having limited impact on tract organization that underlies individual differences in the acquisition and retrieval of lexical and semantic information. SIGNIFICANCE STATEMENT Vocabulary knowledge is resilient to widespread age-related declines in brain structure that limit other cognitive functions. We tested the hypothesis that arcuate fasciculus morphology, which supports the development of reading skills that bolster vocabulary, could explain this relative preservation. We disentangled (1) the effects of age-related declines in arcuate microstructure (mean diffusivity; myelin content estimate) that predicted cognitive processing speed but not vocabulary, from (2) relatively stable arcuate macrostructure (shape/volume) that explained significant variance in an age-independent association between fractional anisotropy and vocabulary. This latter result may reflect differences in fiber trajectory and organization that are resilient to aging. We propose that developmental sculpting of the arcuate fasciculus determines acquisition, storage, and access of lexical information across the adult lifespan. PMID:27383595

High-Order Entropy Stable Finite Difference Schemes for Nonlinear Conservation Laws: Finite Domains

NASA Technical Reports Server (NTRS)

Fisher, Travis C.; Carpenter, Mark H.

2013-01-01

Developing stable and robust high-order finite difference schemes requires mathematical formalism and appropriate methods of analysis. In this work, nonlinear entropy stability is used to derive provably stable high-order finite difference methods with formal boundary closures for conservation laws. Particular emphasis is placed on the entropy stability of the compressible Navier-Stokes equations. A newly derived entropy stable weighted essentially non-oscillatory finite difference method is used to simulate problems with shocks and a conservative, entropy stable, narrow-stencil finite difference approach is used to approximate viscous terms.

Turing patterns and a stochastic individual-based model for predator-prey systems

NASA Astrophysics Data System (ADS)

Nagano, Seido

2012-02-01

Reaction-diffusion theory has played a very important role in the study of pattern formations in biology. However, a group of individuals is described by a single state variable representing population density in reaction-diffusion models and interaction between individuals can be included only phenomenologically. Recently, we have seamlessly combined individual-based models with elements of reaction-diffusion theory. To include animal migration in the scheme, we have adopted a relationship between the diffusion and the random numbers generated according to a two-dimensional bivariate normal distribution. Thus, we have observed the transition of population patterns from an extinction mode, a stable mode, or an oscillatory mode to the chaotic mode as the population growth rate increases. We show our phase diagram of predator-prey systems and discuss the microscopic mechanism for the stable lattice formation in detail.

Beyond Contagion: Reality Mining Reveals Complex Patterns of Social Influence.

PubMed

Alshamsi, Aamena; Pianesi, Fabio; Lepri, Bruno; Pentland, Alex; Rahwan, Iyad

2015-01-01

Contagion, a concept from epidemiology, has long been used to characterize social influence on people's behavior and affective (emotional) states. While it has revealed many useful insights, it is not clear whether the contagion metaphor is sufficient to fully characterize the complex dynamics of psychological states in a social context. Using wearable sensors that capture daily face-to-face interaction, combined with three daily experience sampling surveys, we collected the most comprehensive data set of personality and emotion dynamics of an entire community of work. From this high-resolution data about actual (rather than self-reported) face-to-face interaction, a complex picture emerges where contagion (that can be seen as adaptation of behavioral responses to the behavior of other people) cannot fully capture the dynamics of transitory states. We found that social influence has two opposing effects on states: adaptation effects that go beyond mere contagion, and complementarity effects whereby individuals' behaviors tend to complement the behaviors of others. Surprisingly, these effects can exhibit completely different directions depending on the stable personality or emotional dispositions (stable traits) of target individuals. Our findings provide a foundation for richer models of social dynamics, and have implications on organizational engineering and workplace well-being.

Cognitively-Impaired-Not-Demented Status Moderates the Time-Varying Association between Finger Tapping Inconsistency and Executive Performance.

PubMed

Halliday, Drew W R; Stawski, Robert S; MacDonald, Stuart W S

2017-02-01

Response time inconsistency (RTI) in cognitive performance predicts deleterious health outcomes in late-life; however, RTI estimates are often confounded by additional influences (e.g., individual differences in learning). Finger tapping is a basic sensorimotor measure largely independent of higher-order cognition that may circumvent such confounds of RTI estimates. We examined the within-person coupling of finger-tapping mean and RTI on working memory, and the moderation of these associations by cognitive status. A total of 262 older adults were recruited and classified as controls, cognitively-impaired-not-demented (CIND) unstable or CIND stable. Participants completed finger-tapping and working-memory tasks during multiple weekly assessments, repeated annually for 4 years. Within-person coupling estimates from multilevel models indicated that on occasions when RTI was greater, working-memory response latency was slower for the CIND-stable, but not for the CIND-unstable or control individuals. The finger-tapping task shows potential for minimizing confounds on RTI estimates, and for yielding RTI estimates sensitive to central nervous system function and cognitive status. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Stability Subtypes of Callous-Unemotional Traits and Conduct Disorder Symptoms and Their Correlates.

PubMed

Eisenbarth, Hedwig; Demetriou, Chara A; Kyranides, Melina Nicole; Fanti, Kostas A

2016-09-01

Callous-unemotional traits and conduct disorder symptoms tend to co-occur across development, with existing evidence pointing to individual differences in the co-development of these problems. The current study identified groups of at risk adolescents showing stable (i.e., high on both conduct disorder and callous-unemotional symptoms, high only on either callous-unemotional or conduct disorder symptoms) or increasing conduct disorder and callous-unemotional symptoms. Data were collected from a sample of 2038 community adolescents between 15 and 18 years (1070 females, M age = 16) of age. A longitudinal design was followed in that adolescent reports were collected at two time points, 1 year apart. Increases in conduct disorder symptoms and callous-unemotional traits were accompanied by increases in anxiety, depressive symptoms, narcissism, proactive and reactive aggression and decreases in self-esteem. Furthermore, adolescents with high and stable conduct disorder symptoms and callous-unemotional traits were consistently at high risk for individual, behavioral and contextual problems. In contrast, youth high on callous-unemotional traits without conduct disorder symptoms remained at low-risk for anxiety, depressive symptoms, narcissism, and aggression, pointing to a potential protective function of pure callous-unemotional traits against the development of psychopathological problems.

Habitat stability, predation risk and 'memory syndromes'.

PubMed

Dalesman, S; Rendle, A; Dall, S R X

2015-05-27

Habitat stability and predation pressure are thought to be major drivers in the evolutionary maintenance of behavioural syndromes, with trait covariance only occurring within specific habitats. However, animals also exhibit behavioural plasticity, often through memory formation. Memory formation across traits may be linked, with covariance in memory traits (memory syndromes) selected under particular environmental conditions. This study tests whether the pond snail, Lymnaea stagnalis, demonstrates consistency among memory traits ('memory syndrome') related to threat avoidance and foraging. We used eight populations originating from three different habitat types: i) laboratory populations (stable habitat, predator-free); ii) river populations (fairly stable habitat, fish predation); and iii) ditch populations (unstable habitat, invertebrate predation). At a population level, there was a negative relationship between memories related to threat avoidance and food selectivity, but no consistency within habitat type. At an individual level, covariance between memory traits was dependent on habitat. Laboratory populations showed no covariance among memory traits, whereas river populations showed a positive correlation between food memories, and ditch populations demonstrated a negative relationship between threat memory and food memories. Therefore, selection pressures among habitats appear to act independently on memory trait covariation at an individual level and the average response within a population.

Resting states are resting traits--an FMRI study of sex differences and menstrual cycle effects in resting state cognitive control networks.

PubMed

Hjelmervik, Helene; Hausmann, Markus; Osnes, Berge; Westerhausen, René; Specht, Karsten

2014-01-01

To what degree resting state fMRI is stable or susceptible to internal mind states of the individual is currently an issue of debate. To address this issue, the present study focuses on sex differences and investigates whether resting state fMRI is stable in men and women or changes within relative short-term periods (i.e., across the menstrual cycle). Due to the fact that we recently reported menstrual cycle effects on cognitive control based on data collected during the same sessions, the current study is particularly interested in fronto-parietal resting state networks. Resting state fMRI was measured in sixteen women during three different cycle phases (menstrual, follicular, and luteal). Fifteen men underwent three sessions in corresponding time intervals. We used independent component analysis to identify four fronto-parietal networks. The results showed sex differences in two of these networks with women exhibiting higher functional connectivity in general, including the prefrontal cortex. Menstrual cycle effects on resting states were non-existent. It is concluded that sex differences in resting state fMRI might reflect sexual dimorphisms in the brain rather than transitory activating effects of sex hormones on the functional connectivity in the resting brain.

Resting States Are Resting Traits – An fMRI Study of Sex Differences and Menstrual Cycle Effects in Resting State Cognitive Control Networks

PubMed Central

Hjelmervik, Helene; Hausmann, Markus; Osnes, Berge; Westerhausen, René; Specht, Karsten

2014-01-01

To what degree resting state fMRI is stable or susceptible to internal mind states of the individual is currently an issue of debate. To address this issue, the present study focuses on sex differences and investigates whether resting state fMRI is stable in men and women or changes within relative short-term periods (i.e., across the menstrual cycle). Due to the fact that we recently reported menstrual cycle effects on cognitive control based on data collected during the same sessions, the current study is particularly interested in fronto-parietal resting state networks. Resting state fMRI was measured in sixteen women during three different cycle phases (menstrual, follicular, and luteal). Fifteen men underwent three sessions in corresponding time intervals. We used independent component analysis to identify four fronto-parietal networks. The results showed sex differences in two of these networks with women exhibiting higher functional connectivity in general, including the prefrontal cortex. Menstrual cycle effects on resting states were non-existent. It is concluded that sex differences in resting state fMRI might reflect sexual dimorphisms in the brain rather than transitory activating effects of sex hormones on the functional connectivity in the resting brain. PMID:25057823

Activity of Pure Streptovaricins and Fractionated Streptovaricin Complex Against Friend Virus

PubMed Central

Horoszewicz, Julius S.; Rinehart, Kenneth L.; Leong, Susan S.; Carter, William A.

1975-01-01

Chromatographic fractionation of streptovaricin complex yields two stable components enriched (4- to 16-fold) in activity directed against the polycythemic strain of Friend virus; both components apparently contain no streptovaricins. When compared with their unfractionated parent streptovaricin complex, eight individual intact streptovaricins (A through G and J) show at least a 30-fold reduction in antiviral activity. These results further support the conclusion that the diversified biological properties of streptovaricin complex probably reside in different molecular structures. PMID:237470

Reactivity to unpredictable threat as a treatment target for fear-based anxiety disorders.

PubMed

Gorka, S M; Lieberman, L; Klumpp, H; Kinney, K L; Kennedy, A E; Ajilore, O; Francis, J; Duffecy, J; Craske, M G; Nathan, J; Langenecker, S; Shankman, S A; Phan, K L

2017-10-01

Heightened reactivity to unpredictable threat (U-threat) is a core individual difference factor underlying fear-based psychopathology. Little is known, however, about whether reactivity to U-threat is a stable marker of fear-based psychopathology or if it is malleable to treatment. The aim of the current study was to address this question by examining differences in reactivity to U-threat within patients before and after 12-weeks of selective serotonin reuptake inhibitors (SSRIs) or cognitive-behavioral therapy (CBT). Participants included patients with principal fear (n = 22) and distress/misery disorders (n = 29), and a group of healthy controls (n = 21) assessed 12-weeks apart. A well-validated threat-of-shock task was used to probe reactivity to predictable (P-) and U-threat and startle eyeblink magnitude was recorded as an index of defensive responding. Across both assessments, individuals with fear-based disorders displayed greater startle magnitude to U-threat relative to healthy controls and distress/misery patients (who did not differ). From pre- to post-treatment, startle magnitude during U-threat decreased only within the fear patients who received CBT. Moreover, within fear patients, the magnitude of decline in startle to U-threat correlated with the magnitude of decline in fear symptoms. For the healthy controls, startle to U-threat across the two time points was highly reliable and stable. Together, these results indicate that startle to U-threat characterizes fear disorder patients and is malleable to treatment with CBT but not SSRIs within fear patients. Startle to U-threat may therefore reflect an objective, psychophysiological indicator of fear disorder status and CBT treatment response.

Shifting diet, shifting culture? A bioarchaeological approach to island dietary development on Iron-Age Öland, Baltic Sea.

PubMed

Wilhelmson, Helene

2017-06-01

The diet and subsistence in Iron-Age Öland is debated as earlier studies and different archaeological sources seemingly provide conflicting interpretations. The objectives of this study are therefore to: (i) add new insights on diet and (ii) investigate the chronological variation in detail. It is common in studies of diet to investigate differences between datasets defined by archaeological periods (determined by artefact typology), but it is rare to explore whether these dietary changes are, in fact, well correlated with these temporal categories or not. Stable isotope analysis of 108 individuals and 25 animals was used to interpret diet in comparison with data from earlier studies. Different values of TLE (Trophic Level Effect) for δ 15 N were compared for interpretations of diet. Of the 108 individuals, 42 were subjected to 14 C analysis in this study. The isotopes from Iron-Age animals on Öland indicate that the local, contemporary ecology is specific. The human isotope values show chronological development both when pooled in chronological groups by typology and by more specific 14 C chronology. The new samples of animals as well as the use of 5‰ TLE for δ 15 N values results in the diet reinterpreted as mainly domesticate-based, with at least two shifts in diet occurring in the Iron Age. The use of 14 C dates in connection with the stable isotope results indicates a dietary transition occurring between 200 BC and AD 200, a date range that spans two typologically determined time periods. © 2017 Wiley Periodicals, Inc.

Vineyard zonal management for grape quality assessment by combining airborne remote sensed imagery and soil sensors

NASA Astrophysics Data System (ADS)

Bonilla, I.; Martínez De Toda, F.; Martínez-Casasnovas, J. A.

2014-10-01

Vineyard variability within the fields is well known by grape growers, producing different plant responses and fruit characteristics. Many technologies have been developed in last recent decades in order to assess this spatial variability, including remote sensing and soil sensors. In this paper we study the possibility of creating a stable classification system that better provides useful information for the grower, especially in terms of grape batch quality sorting. The work was carried out during 4 years in a rain-fed Tempranillo vineyard located in Rioja (Spain). NDVI was extracted from airborne imagery, and soil conductivity (EC) data was acquired by an EM38 sensor. Fifty-four vines were sampled at véraison for vegetative parameters and before harvest for yield and grape analysis. An Isocluster unsupervised classification in two classes was performed in 5 different ways, combining NDVI maps individually, collectively and combined with EC. The target vines were assigned in different zones depending on the clustering combination. Analysis of variance was performed in order to verify the ability of the combinations to provide the most accurate information. All combinations showed a similar behaviour concerning vegetative parameters. Yield parameters classify better by the EC-based clustering, whilst maturity grape parameters seemed to give more accuracy by combining all NDVIs and EC. Quality grape parameters (anthocyanins and phenolics), presented similar results for all combinations except for the NDVI map of the individual year, where the results were poorer. This results reveal that stable parameters (EC or/and NDVI all-together) clustering outcomes in better information for a vineyard zonal management strategy.

Neurophysiological measures of involuntary and voluntary attention allocation and dispositional differences in need for cognition.

PubMed

Enge, Sören; Fleischhauer, Monika; Brocke, Burkhard; Strobel, Alexander

2008-06-01

Need for cognition (NFC) refers to stable individual differences in the intrinsic motivation to engage in and enjoy effortful cognitive endeavors and has been a useful predictor of dispositional differences in information processing. Although cognitive resource allocation conceptualized as cognitive effort is assumed to be the key mediator of NFC-specific processing, to date no research has systematically addressed its underpinnings. Using a neurocognitive paradigm and recording event-related potentials associated with bottom-up and top-down-driven aspects of attention, the present research contributes to filling this gap. In Study 1, high-NFC individuals showed larger P3a amplitudes to contextually novel events, indicating greater involuntary (automatic) attention allocation. This effect was replicated in Study 2, where NFC also was positively correlated with the P3b to target stimuli, indicating voluntary (controlled) processes of attention allocation. Thus, our findings provide first evidence for neurophysiological correlates of NFC and can improve the understanding of NFC-specific processing.

Time to stabilization in single leg drop jump landings: an examination of calculation methods and assessment of differences in sample rate, filter settings and trial length on outcome values.

PubMed

Fransz, Duncan P; Huurnink, Arnold; de Boode, Vosse A; Kingma, Idsart; van Dieën, Jaap H

2015-01-01

Time to stabilization (TTS) is the time it takes for an individual to return to a baseline or stable state following a jump or hop landing. A large variety exists in methods to calculate the TTS. These methods can be described based on four aspects: (1) the input signal used (vertical, anteroposterior, or mediolateral ground reaction force) (2) signal processing (smoothed by sequential averaging, a moving root-mean-square window, or fitting an unbounded third order polynomial), (3) the stable state (threshold), and (4) the definition of when the (processed) signal is considered stable. Furthermore, differences exist with regard to the sample rate, filter settings and trial length. Twenty-five healthy volunteers performed ten 'single leg drop jump landing' trials. For each trial, TTS was calculated according to 18 previously reported methods. Additionally, the effects of sample rate (1000, 500, 200 and 100 samples/s), filter settings (no filter, 40, 15 and 10 Hz), and trial length (20, 14, 10, 7, 5 and 3s) were assessed. The TTS values varied considerably across the calculation methods. The maximum effect of alterations in the processing settings, averaged over calculation methods, were 2.8% (SD 3.3%) for sample rate, 8.8% (SD 7.7%) for filter settings, and 100.5% (SD 100.9%) for trial length. Differences in TTS calculation methods are affected differently by sample rate, filter settings and trial length. The effects of differences in sample rate and filter settings are generally small, while trial length has a large effect on TTS values. Copyright © 2014 Elsevier B.V. All rights reserved.

Inattentional Blindness and Individual Differences in Cognitive Abilities.

PubMed

Kreitz, Carina; Furley, Philip; Memmert, Daniel; Simons, Daniel J

2015-01-01

People sometimes fail to notice salient unexpected objects when their attention is otherwise occupied, a phenomenon known as inattentional blindness. To explore individual differences in inattentional blindness, we employed both static and dynamic tasks that either presented the unexpected object away from the focus of attention (spatial) or near the focus of attention (central). We hypothesized that noticing in central tasks might be driven by the availability of cognitive resources like working memory, and that noticing in spatial tasks might be driven by the limits on spatial attention like attention breadth. However, none of the cognitive measures predicted noticing in the dynamic central task or in either the static or dynamic spatial task. Only in the central static task did working memory capacity predict noticing, and that relationship was fairly weak. Furthermore, whether or not participants noticed an unexpected object in a static task was only weakly associated with their odds of noticing an unexpected object in a dynamic task. Taken together, our results are largely consistent with the notion that noticing unexpected objects is driven more by stochastic processes common to all people than by stable individual differences in cognitive abilities.

Inattentional Blindness and Individual Differences in Cognitive Abilities

PubMed Central

Kreitz, Carina; Furley, Philip; Memmert, Daniel; Simons, Daniel J.

2015-01-01

People sometimes fail to notice salient unexpected objects when their attention is otherwise occupied, a phenomenon known as inattentional blindness. To explore individual differences in inattentional blindness, we employed both static and dynamic tasks that either presented the unexpected object away from the focus of attention (spatial) or near the focus of attention (central). We hypothesized that noticing in central tasks might be driven by the availability of cognitive resources like working memory, and that noticing in spatial tasks might be driven by the limits on spatial attention like attention breadth. However, none of the cognitive measures predicted noticing in the dynamic central task or in either the static or dynamic spatial task. Only in the central static task did working memory capacity predict noticing, and that relationship was fairly weak. Furthermore, whether or not participants noticed an unexpected object in a static task was only weakly associated with their odds of noticing an unexpected object in a dynamic task. Taken together, our results are largely consistent with the notion that noticing unexpected objects is driven more by stochastic processes common to all people than by stable individual differences in cognitive abilities. PMID:26258545

Individual differences in the development of early peer aggression: integrating contributions of self-regulation, theory of mind, and parenting.

PubMed

Olson, Sheryl L; Lopez-Duran, Nestor; Lunkenheimer, Erika S; Chang, Hyein; Sameroff, Arnold J

2011-02-01

This prospective longitudinal study focused on self-regulatory, social-cognitive, and parenting precursors of individual differences in children's peer-directed aggression at early school age. Participants were 199 3-year-old boys and girls who were reassessed following the transition to kindergarten (5.5-6 years). Peer aggression was assessed in preschool and school settings using naturalistic observations and teacher reports. Children's self-regulation abilities and theory of mind understanding were assessed during a laboratory visit, and parenting risk (corporal punishment and low warmth/responsiveness) was assessed using interview-based and questionnaire measures. Individual differences in children's peer aggression were moderately stable across the preschool to school transition. Preschool-age children who manifested high levels of aggressive peer interactions also showed lower levels of self-regulation and theory of mind understanding, and experienced higher levels of adverse parenting than others. Our main finding was that early corporal punishment was associated with increased levels of peer aggression across the transition from preschool to school, as was the interaction between low maternal emotional support and children's early delays in theory of mind understanding. These data highlight the need for family-directed preventive efforts during the early preschool years.

USE OF FATTY ACID STABLE CARBON ISOTOPE RATIO TO INDICATE MICROBIAL CARBON SOURCE IN TROPICAL SOILS

EPA Science Inventory

We use measurements of the concentration and stable carbon isotope ratio of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels, broad microbial community structure, and microbial carbon source. For studies of soil o...

75 FR 80889 - Qualification of Drivers; Exemption Applications; Diabetes Mellitus

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-23

... individuals for exemption from the prohibition against persons with insulin-treated diabetes mellitus (ITDM...; understands diabetes management and monitoring; has stable control of his diabetes using insulin; and is able... monitoring; has stable control of his diabetes using insulin; and is able to drive a CMV safely. Mr. Barner...

76 FR 17478 - Qualification of Drivers; Exemption Applications; Diabetes Mellitus

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-29

... individuals for exemption from the prohibition against persons with insulin-treated diabetes mellitus (ITDM... monitoring, has stable control of his diabetes using insulin, and is able to drive a CMV safely. Mr. Amendola... understands diabetes management and monitoring, has stable control of his diabetes using insulin, and is able...

USE OF THE COMPOSITION AND STABLE CARBONIISOTOPE RATIO OF MICROBIAL FATTY ACIDS TO STUDY CARBON CYCLING

EPA Science Inventory

We use measurements of the concentration and stable carbon isotopic ratio (*13C) of individual microbial phospholipid fatty acids (PLFAs) in soils and sediments as indicators of live microbial biomass levels and microbial carbon source. For studies of soil organic matter (SOM) cy...

FATTY ACID STABLE ISOTOPE INDICATORS OF MICROBIAL CARBON SOURCE IN TROPICAL SOILS

EPA Science Inventory

The soil microbial community plays an important role in tropical ecosystem functioning because of its importance in the soil organic matter (SOM) cycle. We have measured the stable carbon isotopic ratio (delta13C) of individual phospholipid fatty acids (PLFAs) in a variety of tr...

Individual variation in functional response parameters is explained by body size but not by behavioural types in a poeciliid fish.

PubMed

Schröder, Arne; Kalinkat, Gregor; Arlinghaus, Robert

2016-12-01

Functional responses are per-capita feeding rate models whose parameters often scale with individual body size but the parameters may also be further influenced by behavioural traits consistently differing among individuals, i.e. behavioural types or animal personalities. Behavioural types may intrinsically lead to lower feeding rates when consistently shy, inactive and easily stressed individuals cannot identify or respond to risk-free environments or need less food due to lower metabolic rates linked to behaviour. To test how much variation in functional response parameters is explained by body size and how much by behavioural types, we estimated attack rate and handling time individually for differently sized female least killifish (Heterandria formosa) and repeatedly measured behavioural traits for each individual. We found that individual fish varied substantially in their attack rate and in their handling time. Behavioural traits were stable over time and varied consistently among individuals along two distinct personality axes. The individual variation in functional responses was explained solely by body size, and contrary to our expectations, not additionally by the existing behavioural types in exploration activity and coping style. While behavioural trait-dependent functional responses may offer a route to the understanding of the food web level consequences of behavioural types, our study is so far only the second one on this topic. Importantly, our results indicate in contrast to that previous study that behavioural types do not per se affect individual functional responses assessed in the absence of external biotic stressors.

Nucleosynthetic and Mass-Dependent Titanium Isotope Variations in Individual Chondrules of Ordinary Chondrites

NASA Astrophysics Data System (ADS)

Schönbächler, M.; Bauer, K. K.; Fehr, M. A.; Chaumard, N.; Zanda, B.

2017-02-01

We present evidence for nucleosynthetic Ti isotope heterogeneity between individual chondrules of ordinary chondrites difficult to reconcile with chondrule formation from molten planetesimals. Metamorphism resulted in stable Ti isotope fractionation.

Quantifying inter- and intra-population niche variability using hierarchical bayesian stable isotope mixing models.

PubMed

Semmens, Brice X; Ward, Eric J; Moore, Jonathan W; Darimont, Chris T

2009-07-09

Variability in resource use defines the width of a trophic niche occupied by a population. Intra-population variability in resource use may occur across hierarchical levels of population structure from individuals to subpopulations. Understanding how levels of population organization contribute to population niche width is critical to ecology and evolution. Here we describe a hierarchical stable isotope mixing model that can simultaneously estimate both the prey composition of a consumer diet and the diet variability among individuals and across levels of population organization. By explicitly estimating variance components for multiple scales, the model can deconstruct the niche width of a consumer population into relevant levels of population structure. We apply this new approach to stable isotope data from a population of gray wolves from coastal British Columbia, and show support for extensive intra-population niche variability among individuals, social groups, and geographically isolated subpopulations. The analytic method we describe improves mixing models by accounting for diet variability, and improves isotope niche width analysis by quantitatively assessing the contribution of levels of organization to the niche width of a population.

Comparison of the bioavailability and adhesiveness of different rotigotine transdermal patch formulations.

PubMed

Elshoff, Jan-Peer; Timmermann, Lars; Schmid, Miriam; Arth, Christoph; Komenda, Michael; Brunnert, Marcus; Bauer, Lars

2013-12-01

Rotigotine transdermal patch is approved for the treatment of early and advanced idiopathic Parkinson's disease (PD) and moderate-to-severe idiopathic restless legs syndrome (RLS). A cold chain manufacturing and distribution process was temporarily implemented in 2008, as this reduced the crystal formation reported within patches stored at room temperature. In order to overcome the crystallization issue and meet EMA and FDA requirements, a new room temperature stable formulation was developed. The three studies reported here were conducted to determine whether the new room temperature stable patch demonstrated similar bioavailability and adhesiveness to the original and intermediate patches. Data are reported from three cross-over studies that compared the original, cold chain and room temperature stable patch. Two open-label bioequivalence studies investigated the 2 mg/24 h dosage in healthy individuals (SP951, n = 52 [Clinicaltrials.gov: NCT00881894]; SP0987, n = 50 [NCT01059903]) and a double-blind patch adhesiveness study investigated the 8 mg/24 h dosage in patients with PD (SP1066, n = 56 [NCT01338896]). Plasma concentration-time curves and geometric means for pharmacokinetic parameters were similar for the cold chain vs. original patch in SP951 (AUC(0-tz): 2.68 vs. 2.71 ng/mL*h; point estimate: 0.99 [90% confidence interval (CI): 0.91, 1.07]) (Cmax: 0.131 vs. 0.136 ng/mL; 0.96 [0.89, 1.04]) and for the room temperature stable vs. cold chain patch in SP0987 (AUC(0-tz): 4.51 vs. 4.87 ng/mL*h; 0.90 [0.84, 0.97]) (Cmax: 0.23 vs. 0.23 ng/mL; 0.95 [0.88, 1.02]). In both studies, 90% CIs for ratios of AUC(0-tz) and Cmax were within the bioequivalence acceptance range (0.8-1.25). In SP1066, overall median adhesiveness scores were similar for cold chain (0.5 [range: 0-4]) and room temperature stable (0 [0-4]) formulations. These results demonstrated bioequivalence and indicated similar adhesiveness of the approved room temperature stable rotigotine patch with the original and cold chain patches. Potential limitations include the enrolment of healthy volunteers in the bioequivalence studies, as these individuals were likely to be younger than the general PD or RLS population.

Emergence of Leadership within a Homogeneous Group

PubMed Central

Eskridge, Brent E.; Valle, Elizabeth; Schlupp, Ingo

2015-01-01

Large scale coordination without dominant, consistent leadership is frequent in nature. How individuals emerge from within the group as leaders, however transitory this position may be, has become an increasingly common question asked. This question is further complicated by the fact that in many of these aggregations, differences between individuals are minor and the group is largely considered to be homogeneous. In the simulations presented here, we investigate the emergence of leadership in the extreme situation in which all individuals are initially identical. Using a mathematical model developed using observations of natural systems, we show that the addition of a simple concept of leadership tendencies which is inspired by observations of natural systems and is affected by experience can produce distinct leaders and followers using a nonlinear feedback loop. Most importantly, our results show that small differences in experience can promote the rapid emergence of stable roles for leaders and followers. Our findings have implications for our understanding of adaptive behaviors in initially homogeneous groups, the role experience can play in shaping leadership tendencies, and the use of self-assessment in adapting behavior and, ultimately, self-role-assignment. PMID:26226381

Emergence of Leadership within a Homogeneous Group.

PubMed

Eskridge, Brent E; Valle, Elizabeth; Schlupp, Ingo

2015-01-01

Large scale coordination without dominant, consistent leadership is frequent in nature. How individuals emerge from within the group as leaders, however transitory this position may be, has become an increasingly common question asked. This question is further complicated by the fact that in many of these aggregations, differences between individuals are minor and the group is largely considered to be homogeneous. In the simulations presented here, we investigate the emergence of leadership in the extreme situation in which all individuals are initially identical. Using a mathematical model developed using observations of natural systems, we show that the addition of a simple concept of leadership tendencies which is inspired by observations of natural systems and is affected by experience can produce distinct leaders and followers using a nonlinear feedback loop. Most importantly, our results show that small differences in experience can promote the rapid emergence of stable roles for leaders and followers. Our findings have implications for our understanding of adaptive behaviors in initially homogeneous groups, the role experience can play in shaping leadership tendencies, and the use of self-assessment in adapting behavior and, ultimately, self-role-assignment.

Genetic variation in serotonin function impacts on altruistic punishment in the ultimatum game: A longitudinal approach.

PubMed

Gärtner, Anne; Strobel, Alexander; Reif, Andreas; Lesch, Klaus-Peter; Enge, Sören

2018-05-30

Growing evidence demonstrates that the serotonin system influences punishment behavior in social decision-making and that individual differences in the propensity to punish are, at least in part, due to genetic variation. However, the specific genes and their mechanisms by which they influence punishment behavior are not yet fully characterized. Here, we examined whether serotonin system-related gene variation impacts on altruistic punishment in the ultimatum game by using a longitudinal approach with three time points, covering a time frame up to four months in young adults (N = 106). Specifically, we investigated additive effects of 5-HTTLPR and TPH2 G-703T genotypes by using a composite score. This composite score was significantly associated with altruistic punishment, with individuals carrying both the S-allele and the G-allele demonstrating less punishment behavior. The results suggest that serotonin system-related gene variation contributes to individual differences in altruistic punishment. Furthermore, comparably high test-retest correlations suggest that punishment behavior in the ultimatum game represents a relatively stable, trait-like behavior. Copyright © 2018 Elsevier Inc. All rights reserved.

Correlation of individual differences in audiovisual asynchrony across stimuli and tasks: New constraints on temporal renormalization theory.

PubMed

Ipser, Alberta; Karlinski, Maayan; Freeman, Elliot D

2018-05-07

Sight and sound are out of synch in different people by different amounts for different tasks. But surprisingly, different concurrent measures of perceptual asynchrony correlate negatively (Freeman et al., 2013). Thus, if vision subjectively leads audition in one individual, the same individual might show a visual lag in other measures of audiovisual integration (e.g., McGurk illusion, Stream-Bounce illusion). This curious negative correlation was first observed between explicit temporal order judgments and implicit phoneme identification tasks, performed concurrently as a dual task, using incongruent McGurk stimuli. Here we used a new set of explicit and implicit tasks and congruent stimuli, to test whether this negative correlation persists across testing sessions, and whether it might be an artifact of using specific incongruent stimuli. None of these manipulations eliminated the negative correlation between explicit and implicit measures. This supports the generalizability and validity of the phenomenon, and offers new theoretical insights into its explanation. Our previously proposed "temporal renormalization" theory assumes that the timings of sensory events registered within the brain's different multimodal subnetworks are each perceived relative to a representation of the typical average timing of such events across the wider network. Our new data suggest that this representation is stable and generic, rather than dependent on specific stimuli or task contexts, and that it may be acquired through experience with a variety of simultaneous stimuli. Our results also add further evidence that speech comprehension may be improved in some individuals by artificially delaying voices relative to lip-movements. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Transfer of Learning Relates to Intrinsic Connectivity between Hippocampus, Ventromedial Prefrontal Cortex, and Large-Scale Networks

PubMed Central

Gerraty, Raphael T.; Davidow, Juliet Y.; Wimmer, G. Elliott; Kahn, Itamar

2014-01-01

An important aspect of adaptive learning is the ability to flexibly use past experiences to guide new decisions. When facing a new decision, some people automatically leverage previously learned associations, while others do not. This variability in transfer of learning across individuals has been demonstrated repeatedly and has important implications for understanding adaptive behavior, yet the source of these individual differences remains poorly understood. In particular, it is unknown why such variability in transfer emerges even among homogeneous groups of young healthy participants who do not vary on other learning-related measures. Here we hypothesized that individual differences in the transfer of learning could be related to relatively stable differences in intrinsic brain connectivity, which could constrain how individuals learn. To test this, we obtained a behavioral measure of memory-based transfer outside of the scanner and on a separate day acquired resting-state functional MRI images in 42 participants. We then analyzed connectivity across independent component analysis-derived brain networks during rest, and tested whether intrinsic connectivity in learning-related networks was associated with transfer. We found that individual differences in transfer were related to intrinsic connectivity between the hippocampus and the ventromedial prefrontal cortex, and between these regions and large-scale functional brain networks. Together, the findings demonstrate a novel role for intrinsic brain dynamics in flexible learning-guided behavior, both within a set of functionally specific regions known to be important for learning, as well as between these regions and the default and frontoparietal networks, which are thought to serve more general cognitive functions. PMID:25143610

Exploring Differences in Dogs’ and Wolves’ Preference for Risk in a Foraging Task

PubMed Central

Marshall-Pescini, Sarah; Besserdich, Ingo; Kratz, Corinna; Range, Friederike

2016-01-01

Both human and non-humans species face decisions in their daily lives which may entail taking risks. At the individual level, a propensity for risk-taking has been shown to be positively correlated with explorative tendencies, whereas, at the species level a more variable and less stable feeding ecology has been associated with a greater preference for risky choices. In the current study we compared two closely related species; wolves and dogs, which differ significantly in their feeding ecology and their explorative tendencies. Wolves depend on hunting for survival with a success rate of between 15 and 50%, whereas free-ranging dogs (which make up 80% of the world dog population), are largely scavengers specialized on human produce (i.e., a more geographically and temporally stable resource). Here, we used a foraging paradigm, which allowed subjects to choose between a guaranteed less preferred food vs. a more preferred food, which was however, delivered only 50% of the time (a stone being delivered the rest of time). We compared identically raised adult wolves and dogs and found that in line with the differing feeding ecologies of the two species and their explorative tendencies, wolves were more risk prone than dogs. PMID:27602005

"Hits" emerge through self-organized coordination in collective response of free agents

NASA Astrophysics Data System (ADS)

Chakrabarti, Anindya S.; Sinha, Sitabhra

2016-10-01

Individuals in free societies frequently exhibit striking coordination when making independent decisions en masse. Examples include the regular appearance of hit products or memes with substantially higher popularity compared to their otherwise equivalent competitors or extreme polarization in public opinion. Such segregation of events manifests as bimodality in the distribution of collective choices. Here we quantify how apparently independent choices made by individuals result in a significantly polarized but stable distribution of success in the context of the box-office performance of movies and show that it is an emergent feature of a system of noninteracting agents who respond to sequentially arriving signals. The aggregate response exhibits extreme variability amplifying much smaller differences in individual cost of adoption. Due to self-organization of the competitive landscape, most events elicit only a muted response but a few stimulate widespread adoption, emerging as "hits".

"Hits" emerge through self-organized coordination in collective response of free agents.

PubMed

Chakrabarti, Anindya S; Sinha, Sitabhra

2016-10-01

Individuals in free societies frequently exhibit striking coordination when making independent decisions en masse. Examples include the regular appearance of hit products or memes with substantially higher popularity compared to their otherwise equivalent competitors or extreme polarization in public opinion. Such segregation of events manifests as bimodality in the distribution of collective choices. Here we quantify how apparently independent choices made by individuals result in a significantly polarized but stable distribution of success in the context of the box-office performance of movies and show that it is an emergent feature of a system of noninteracting agents who respond to sequentially arriving signals. The aggregate response exhibits extreme variability amplifying much smaller differences in individual cost of adoption. Due to self-organization of the competitive landscape, most events elicit only a muted response but a few stimulate widespread adoption, emerging as "hits".

Prevalence of individual and bulk tank milk antibodies of bovine herpesvirus type 1 and its relation to milk quality parameters on dairy farms in Catalonia (north-east Spain)

PubMed Central

Armengol, Ramon; Villalba, Daniel; Coma, Ester; Porquet, Lourdes; Jubert, Anna

2017-01-01

Bovine herpesvirus type 1 (BoHV-1) is the causative agent for infectious bovine rhinotracheitis and infectious pustular vulvovaginitis in cows or balanoposthitis in bulls. In this study, individual and bulk tank milk (BTM) samples from 5 Catalan dairy farms with different control strategies against BoHV-1 were analysed during the course of a year for milk quality parameters and glycoprotein E (gE) antibodies. Detection of gE antibodies was carried out with ELISA techniques. Prevalence of BoHV-1 varied between farms, and was stable during the study in individual and BTM samples. Comparing the antibody results of samples with milk quality parameters, positive samples with higher levels of antibodies corresponded to lower lactose and to higher percentages of fat and somatic cells. PMID:28761669

Intra-individual and inter-individual variations in sperm aneuploidy frequencies in normal men.

PubMed

Tempest, Helen G; Ko, Evelyn; Rademaker, Alfred; Chan, Peter; Robaire, Bernard; Martin, Renée H

2009-01-01

To investigate whether there are intra-individual and/or inter-individual variations in sperm aneuploidy frequencies within the normal male population, and, if this is the case, whether they are sporadic or time-stable variants. Prospective study. University research laboratory. Ten men aged 18-32 years. None. Fluorescence in situ hybridization was used to investigate sperm aneuploidy frequencies for chromosomes X, Y, 13, and 21 in serial semen samples collected over a period of 12-18 months. Intra-individual and inter-individual variations were investigated by comparing serial samples from the same donor and by comparing the donors with each other, respectively. Intra-individual variations were found in all 10 donors for at least one investigated chromosome; variations tended to be sporadic events affecting only one time point. Inter-individual variations were found for all chromosomes (except XX and YY disomy and disomy 21), with three men identified as stable variants, consistently producing higher levels of aneuploidy for at least one of the following aneuploidies: sex chromosome nullisomy; disomy 13, or diploidy. These results suggest that there are a number of factors and mechanisms that have the potential to sporadically or consistently affect sperm aneuploidy.

When intensions do not map onto extensions: Individual differences in conceptualization.

PubMed

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).

Stable-isotope analysis of a deep-sea benthic-fish assemblage: evidence of an enriched benthic food web.

PubMed

Boyle, M D; Ebert, D A; Cailliet, G M

2012-04-01

In this study, fishes and invertebrates collected from the continental slope (1000 m) of the eastern North Pacific Ocean were analysed using stable-isotope analysis (SIA). Resulting trophic positions (T(P) ) were compared to known diets and habitats from the literature. Dual isotope plots indicated that most species groups (invertebrates and fishes) sorted as expected along the carbon and nitrogen axes, with less intraspecific variability than interspecific variability. Results also indicated an isotopically distinct benthic and pelagic food web, as the benthic food web was more enriched in both nitrogen and carbon isotopes. Trophic positions from SIA supported this finding, resulting in the assignment of fishes to different trophic positions from those expected based on published dietary information. These differences can be explained largely by the habitat of the prey and the percentage of the diet that was scavenged. A mixing model estimated dietary contributions of prey similar to those of the known diet of Bathyraja trachura from stomach-content analysis (SCA). Linear regressions indicated that trophic positions calculated from SIA and SCA, when plotted against B. trachura total length for 32 individuals, exhibited similar variation and patterns. Only the T(P) from SCA yielded significant results (stomach content: P < 0·05, stable isotope: P > 0·05). © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Spatial and temporal variation of diet within a presumed metapopulation of Adelie penguins

USGS Publications Warehouse

Ainley, D.G.; Ballard, G.; Barton, K.J.; Karl, B.J.; Rau, G.H.; Ribic, C.A.; Wilson, P.R.

2003-01-01

We investigated temporal and spatial variability in the diet of chick-provisioning Ade??lie Penguins (Pygoscelis adeliae) breeding at all colonies within one isolated cluster in the southwestern Ross Sea, Antarctica, 1994-2000. We wished to determine if prey quality explained different population growth and emigration rates among colonies. Diet composition was described both by conventional means (stomach samples) and by analysis of stable isotopes in chick tissues (toenails of individuals killed by skuas [Stercorarius maccormicki]). Diets were similar among the four study colonies compared to the disparity apparent among 14 widely spaced sites around the continent. Calorimetry indicated that fish are more energetically valuable than krill, implying that if diet varied by colony, diet quality could attract recruits and help to explain differential rates of colony growth. However, a multiple-regression analysis indicated that diet varied as a function of year, time within the year, and percent of foraging area covered by sea ice, but not by colony location. Stable isotopes revealed similarity of diet at one colony where conventional sampling was not possible. We confirmed that sea ice importantly affects diet composition of this species in neritic waters, and found that (1) quality of summer diet cannot explain different population growth rates among colonies, and (2) stable isotope analysis of chick tissues (toenails) is a useful tool to synoptically describe diet in this species over a large area.

Investigating preferences for color-shape combinations with gaze driven optimization method based on evolutionary algorithms.

PubMed

Holmes, Tim; Zanker, Johannes M

2013-01-01

Studying aesthetic preference is notoriously difficult because it targets individual experience. Eye movements provide a rich source of behavioral measures that directly reflect subjective choice. To determine individual preferences for simple composition rules we here use fixation duration as the fitness measure in a Gaze Driven Evolutionary Algorithm (GDEA), which has been demonstrated as a tool to identify aesthetic preferences (Holmes and Zanker, 2012). In the present study, the GDEA was used to investigate the preferred combination of color and shape which have been promoted in the Bauhaus arts school. We used the same three shapes (square, circle, triangle) used by Kandinsky (1923), with the three color palette from the original experiment (A), an extended seven color palette (B), and eight different shape orientation (C). Participants were instructed to look for their preferred circle, triangle or square in displays with eight stimuli of different shapes, colors and rotations, in an attempt to test for a strong preference for red squares, yellow triangles and blue circles in such an unbiased experimental design and with an extended set of possible combinations. We Tested six participants extensively on the different conditions and found consistent preferences for color-shape combinations for individuals, but little evidence at the group level for clear color/shape preference consistent with Kandinsky's claims, apart from some weak link between yellow and triangles. Our findings suggest substantial inter-individual differences in the presence of stable individual associations of color and shapes, but also that these associations are robust within a single individual. These individual differences go some way toward challenging the claims of the universal preference for color/shape combinations proposed by Kandinsky, but also indicate that a much larger sample size would be needed to confidently reject that hypothesis. Moreover, these experiments highlight the vast potential of the GDEA methodology in experimental aesthetics and beyond.

Is the Limit-Cycle-Attractor an (almost) invariable characteristic in human walking?

PubMed

Broscheid, Kim-Charline; Dettmers, Christian; Vieten, Manfred

2018-05-16

Common methods of gait analyses measure step length/width, gait velocity and gait variability to name just a few. Those parameters tend to be changing with fitness and skill of the subjects. But, do stable subject characteristic parameters in walking exist? Does the Limit-Cycle-Attractor qualify as such a parameter?. The attractor method is a new approach focusing on the dynamics of human motion. It classifies the fundamental walking pattern by calculating the Limit-Cycle-Attractor and its variability from acceleration data of the feet. Our hypothesis is that the fundamental walking pattern in healthy controls and in people with Multiple Sclerosis (pwMS) is stable, but can be altered through acute interventions or rehabilitation. For this purpose, two investigations were conducted involving 113 subjects. The short-term stability was tested pre and post a 15 min passive/active MOTOmed (ergometer) session as well as up to 20 min afterwards. The long-term stability was tested over five weeks of rehabilitation once a week in pwMS. The main parameter of interest describes the velocity normalized average difference between two attractors (δM), which is an indicator for the change in movement pattern. The Friedman's two-way ANOVA by ranks did not reveal any significant difference in δM. However, the conventional walking tests (6 min.10 m) improved significantly (p < 0.05) during rehabilitation. Contrary to our original hypothesis, the fundamental walking pattern was highly stable against controlled motor-assisted movement initiation via MOTOmed and rehabilitation treatment. Movement characteristics appeared to be independent of the improved fitness as indicated by the enhanced walking speed and distance. The individual Limit-Cycle-Attractor is extremely robust and might indeed qualify as an (almost) invariable characteristic in human walking. This opens up the possibility to encode the individual walking characteristics. Conditions as Parkinson, Multiple Sclerosis etc., might display disease specific distinctions via the Limit-Cycle-Attractor. Copyright © 2018 Elsevier B.V. All rights reserved.

No Associations between Interindividual Differences in Sleep Parameters and Episodic Memory Consolidation

PubMed Central

Ackermann, Sandra; Hartmann, Francina; Papassotiropoulos, Andreas; de Quervain, Dominique J.F.; Rasch, Björn

2015-01-01

Study Objectives: Sleep and memory are stable and heritable traits that strongly differ between individuals. Sleep benefits memory consolidation, and the amount of slow wave sleep, sleep spindles, and rapid eye movement sleep have been repeatedly identified as reliable predictors for the amount of declarative and/or emotional memories retrieved after a consolidation period filled with sleep. These studies typically encompass small sample sizes, increasing the probability of overestimating the real association strength. In a large sample we tested whether individual differences in sleep are predictive for individual differences in memory for emotional and neutral pictures. Design: Between-subject design. Setting: Cognitive testing took place at the University of Basel, Switzerland. Sleep was recorded at participants' homes, using portable electroencephalograph-recording devices. Participants: Nine hundred-twenty-nine healthy young participants (mean age 22.48 ± 3.60 y standard deviation). Interventions: None. Measurements and results: In striking contrast to our expectations as well as numerous previous findings, we did not find any significant correlations between sleep and memory consolidation for pictorial stimuli. Conclusions: Our results indicate that individual differences in sleep are much less predictive for pictorial memory processes than previously assumed and suggest that previous studies using small sample sizes might have overestimated the association strength between sleep stage duration and pictorial memory performance. Future studies need to determine whether intraindividual differences rather than interindividual differences in sleep stage duration might be more predictive for the consolidation of emotional and neutral pictures during sleep. Citation: Ackermann S, Hartmann F, Papassotiropoulos A, de Quervain DJF, Rasch B. No associations between interindividual differences in sleep parameters and episodic memory consolidation. SLEEP 2015;38(6):951–959. PMID:25325488

Multiple Diphtheria Antigen-Antibody Systems Investigated by Passive Haemagglutination Techniques and Other Methods

PubMed Central

Fulthorpe, A. J.

1962-01-01

A fair degree of correlation has been found between the in vivo antitoxin content of sera from horses immunized with crude Corynebacterium diphtheriae culture filtrates and the direct agglutinin titre of the sera when tested with sheep cells sensitized with diphtheria toxoid. Haemagglutination inhibition tests at the LA level of test with the same sera showed some rather large discrepancies from the in vivo and further tests with special agglutinin inhibiting toxins suggested that specific antitoxin free from other accessory antibodies might be non-agglutinating, and therefore not titratable by haemagglutination inhibition. The phosphate-stable, pepsin-stable and trypsin-stable antigens isolated from culture filtrates of C. diphtheriae were found to contain extremely small quantities of specific toxoid, and cross titration of each of the three antigen preparations showed that there was very little contamination by other antigens within the group. Absorption of diphtheria antiserum with red cells sensitized with each of the three accessory antigens individually, showed that the antibodies were highly specific and distinct. Absorption of diphtheria antiserum with a mixture of red cells sensitized with the three different antigens removed all demonstrable accessory antibodies, and the absorbed serum would no longer agglutinate cells sensitized with complete diphtheria toxoid. The absorbed serum, however, retained a large proportion of its neutralizing capacity for diphtheria toxin, when titrated in vivo. Titration of each of the accessory antibodies in a number of horse sera by haemagglutination inhibition demonstrated a correlation between the values for the accessory antibodies to the phosphate-stable and pepsin-stable antigens, but no correlation with the values for the antibody to the trypsin-stable antigen, when compared with results of the flocculation test. The relative proportions of diphtheria toxin and of the phosphate-stable and pepsin-stable antigens remained constant at all stages of purification of a filtrate including several recrystallization procedures. However, the concentration of the trypsin-stable antigen declined steadily during the process. The relative proportions of toxin, phosphate-stable and pepsin-stable antigens in several crude culture filtrates were constant under reasonable conditions of storage and very varied where deterioration had occurred. These three antigens also maintained a constant ratio in growing culture, the trypsin-stable antigen did not. PMID:13895880

Operating principles of tristable circuits regulating cellular differentiation

NASA Astrophysics Data System (ADS)

Jia, Dongya; Jolly, Mohit Kumar; Harrison, William; Boareto, Marcelo; Ben-Jacob, Eshel; Levine, Herbert

2017-06-01

Many cell-fate decisions during embryonic development are governed by a motif comprised of two transcription factors (TFs) A and B that mutually inhibit each other and may self-activate. This motif, called as a self-activating toggle switch (SATS), can typically have three stable states (phenotypes)—two corresponding to differentiated cell fates, each of which has a much higher level of one TF than the other—≤ft(A,~B\\right)=≤ft(1,~0\\right) or ≤ft(0,~1\\right) —and the third state corresponding to an ‘undecided’ stem-like state with similar levels of both A and B—≤ft(A,~B\\right)=≤ft(1/2,1/2\\right) . Furthermore, two or more SATSes can be coupled together in various topologies in different contexts, thereby affecting the coordination between multiple cellular decisions. However, two questions remain largely unanswered: (a) what governs the co-existence and relative stability of these three stable states? (b) What orchestrates the decision-making of coupled SATSes? Here, we first demonstrate that the co-existence and relative stability of the three stable states in an individual SATS can be governed by the relative strength of self-activation, external signals activating and/or inhibiting A and B, and mutual degradation between A and B. Simultaneously, we investigate the effects of these factors on the decision-making of two coupled SATSes. Our results offer novel understanding into the operating principles of individual and coupled tristable self-activating toggle switches (SATSes) regulating cellular differentiation and can yield insights into synthesizing three-way genetic circuits and understanding of cellular reprogramming.

The development of family alliance from pregnancy to toddlerhood and child outcomes at 5 years.

PubMed

Favez, Nicolas; Lopes, Francesco; Bernard, Mathieu; Frascarolo, France; Lavanchy Scaiola, Chloe; Corboz-Warnery, Antoinette; Fivaz-Depeursinge, Elisabeth

2012-12-01

This article presents a longitudinal study of the development of "family alliance" from pregnancy to toddlerhood in a community sample, as well as its links with the emotional and cognitive development of the child at age 5 years. Family alliance is defined as the quality of the interactive coordination between family members. We consider that the alliance constitutes a context for the child to learn emotion regulation and to develop an understanding of inner states. Family interactions (N = 38) were observed at the 5th month of pregnancy and at 3, 9, and 18 months after birth in a standardized situation of observation (Lausanne Trilogue Play). Marital satisfaction and child temperament were assessed through self-reported questionnaires. Several outcomes of the child at age 5 years were measured: theory of mind performances, predominant emotional themes in pretend play, internalized and externalized symptoms. Results show that (a) three patterns of evolution of family alliance occur: "high stable" (n = 19), "high to low" (n = 10), and "low stable" (n = 9); (b) a high stable alliance is predictive of better outcomes in children at age 5 years, especially regarding theory of mind; (c) the temperament of the child is predictive of child outcomes; and (d) an interaction effect occurs between family alliance and temperament. These results highlight the importance of both family-level and individual-level variables for understanding individual differences in the social and cognitive development of children. © FPI, Inc.

Identifying Stable Variants of Callous-Unemotional Traits: A Longitudinal Study of At-Risk Girls

ERIC Educational Resources Information Center

Goulter, Natalie; Kimonis, Eva R.; Hawes, Samuel W.; Stepp, Stephanie; Hipwell, Alison E.

2017-01-01

Callous-unemotional (CU) traits have proven important for designating children and adolescents showing a pattern of particularly severe, stable, and aggressive antisocial behaviors (Frick, Ray, Thornton, & Kahn, 2014). Individuals with secondary CU traits represent a subpopulation that are distinguished from those with primary CU traits by…

Predictors of Stable Employment among Female Inmates in New Jersey: Implications for Successful Reintegration

ERIC Educational Resources Information Center

Blitz, Cynthia L.

2006-01-01

The ability of inmates to secure stable, legal employment for themselves upon release from prison has been shown to be a crucial element for successful community reintegration. These individuals, however, often fail to find employment due to a multitude of personal, relational, structural, and institutional barriers. Formerly incarcerated women…

USE OF GC-MS/COMBUSTION/IRMS TO IDENTIFY AND DETERMINE THE STABLE CARBON ISOTOPIC RATIO OF INDIVIDUAL LIPIDS

EPA Science Inventory

A system that couples a gas chromatograph (GC) via a split to a quadrapole mass spectrometer (MS) and, through a combustion interface, to an isotope ratio mass spectrometer (IRMS) allows the simultaneous detection of electron impact mass spectra and stable carbon isotope ratio an...

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans

USDA-ARS?s Scientific Manuscript database

Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool to enable individuals to lose weight. In a pilot study, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath d13C values) reflects shifts between negat...

Getting a Picture that Is Both Accurate and Stable: Situation Models and Epistemic Validation

ERIC Educational Resources Information Center

Schroeder, Sascha; Richter, Tobias; Hoever, Inga

2008-01-01

Text comprehension entails the construction of a situation model that prepares individuals for situated action. In order to meet this function, situation model representations are required to be both accurate and stable. We propose a framework according to which comprehenders rely on epistemic validation to prevent inaccurate information from…

USE OF THE COMPOSITION AND STABLE CARBON ISOTOPE RATIO OF MICROBIAL FATTY ACIDS TO STUDY CARBON CYCLING

EPA Science Inventory

We use measurements of the concentration and stable carbon isotopic ratio (Gamma 13C) of individual microbial phospholipid fatty acids (PLFAS) in soils and sediments as indicators of live microbial biomass levels and microbial carbon source. For studies of soil organic matter (SO...

USE OF STABLE CARBON ISOTOPE RATIOS OF FATTY ACIDS TO EVALUATE MICROBIAL CARBON SOURCES IN TERRESTRIAL ENVIRONMENTS

EPA Science Inventory

We use measurements of the concentration and stable carbon isotopic ratio (D 13C) of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels and microbial carbon source. We found that intensive sugar cane cultivation leads to ...

Time-response of cultured deep-sea benthic foraminifera to different algal diets

NASA Astrophysics Data System (ADS)

Heinz, P.; Hemleben, Ch; Kitazato, H.

2002-03-01

The vertical distribution of benthic foraminifera in the surface sediment is influenced by environmental factors, mainly by food and oxygen supply. An experiment of three different time series was performed to investigate the response of deep-sea benthic foraminifera to simulated phytodetritus pulses under stable oxygen concentrations. Each series was fed constantly with one distinct algal species in equivalent amounts. The temporal reactions of the benthic foraminifera with regard to the vertical distribution in the sediment, the total number, and the species composition were observed and compared within the three series. Additionally, oxygen contents and bacterial cell numbers were measured to ensure that these factors were invariable and did not influence foraminiferal communities. The addition of algae leads to higher population densities 21 days after food was added. Higher numbers of individuals were probably caused by higher organic levels, which in turn induced reproduction. A stronger response is found after feeding with Amphiprora sp. and Pyramimonas sp., compared to Dunaliella tertiolecta. At a constant high oxygen supply, no migration to upper layers was observed after food addition, and more individuals were found in deeper layers. The laboratory results thus agree with the predictions of the TROX-model. An epifaunal microhabitat preference was shown for Adercotryma glomerata. Hippocrepina sp. was spread over the entire sediment depth with a shallow infaunal maximum. Melonis barleeanum preferred a deeper infaunal habitat. Bacterial cell concentrations were stable during the laboratory experiments and showed no significant response to higher organic fluxes.

Variability in Puff Topography and Exhaled CO in Waterpipe Tobacco Smoking.

PubMed

Kim, Hyoshin; Brinkman, Marielle C; Sharma, Eva; Gordon, Sydney M; Clark, Pamela I

2016-10-01

We examined intra-individual variability in puff topography and CO measures collected during laboratory waterpipe (WP) tobacco smoking using a research-grade waterpipe (RWP). WP smoking topography and exhaled CO measures were obtained from 10 established WP smokers in a single-blind, crossover design. Using a previously validated RWP, each participant smoked "Two Apples" WP tobacco ad libitum with a single quick-light charcoal to satiation in 3 laboratory sessions spaced at least one week apart. To examine the intra-individual variability, the intraclass correlation coefficient ( ρ ) for topography and CO measures were estimated. Results: The majority of the topography and CO measures were stable. Most stable were puff frequency ( ρ = 0.88), number of puffs ( ρ = 0.86), and puff duration (ρ = 0.80). Less stable were peak flow ( ρ = 0.57) and total puff volume ( ρ = 0.52). The results provide the first set of empirical evidence that most topography and CO measurements collected using the RWP from a single laboratory smoking session are stable such that they can be representative of a smoker's puffing behaviors and reproducible among 3 sessions spread equally across 3 weeks.

Abnormal-induced theta activity supports early directed-attention network deficits in progressive MCI.

PubMed

Deiber, Marie-Pierre; Ibañez, Vicente; Missonnier, Pascal; Herrmann, François; Fazio-Costa, Lara; Gold, Gabriel; Giannakopoulos, Panteleimon

2009-09-01

The electroencephalography (EEG) theta frequency band reacts to memory and selective attention paradigms. Global theta oscillatory activity includes a posterior phase-locked component related to stimulus processing and a frontal-induced component modulated by directed attention. To investigate the presence of early deficits in the directed attention-related network in elderly individuals with mild cognitive impairment (MCI), time-frequency analysis at baseline was used to assess global and induced theta oscillatory activity (4-6Hz) during n-back working memory tasks in 29 individuals with MCI and 24 elderly controls (EC). At 1-year follow-up, 13 MCI patients were still stable and 16 had progressed. Baseline task performance was similar in stable and progressive MCI cases. Induced theta activity at baseline was significantly reduced in progressive MCI as compared to EC and stable MCI in all n-back tasks, which were similar in terms of directed attention requirements. While performance is maintained, the decrease of induced theta activity suggests early deficits in the directed-attention network in progressive MCI, whereas this network is functionally preserved in stable MCI.

Characterizing Early Maternal Style in a Population of Guide Dogs

PubMed Central

Bray, Emily E.; Sammel, Mary D.; Cheney, Dorothy L.; Serpell, James A.; Seyfarth, Robert M.

2017-01-01

In both humans and non-humans, differences in maternal style during the first few weeks of life can be reliably characterized, and these differences affect offspring's temperament and cognition in later life. Drawing on the breeding population of dogs at The Seeing Eye, a guide dog school in Morristown, New Jersey, we conducted videotaped focal follows on 21 mothers and their litters (n = 138 puppies) over the first 3 weeks of the puppies' lives in an effort to characterize maternal style. We found that a mother's attitude and actions toward her offspring varied naturally between individuals, and that these variations could be summarized by a single principal component, which we described as Maternal behavior. This component was stable across weeks, associated with breed, litter size, and parity, but not redundant with these attributes. Furthermore, this component was significantly associated with an independent experimental measure of maternal behavior, and with maternal stress as measured by salivary cortisol. In summary, Maternal behavior captured a significant proportion of the variation in maternal style; was stable over time; and had both discriminant and predictive validity. PMID:28239365

Phenotypic vulnerability of energy balance responses to sleep loss in healthy adults

PubMed Central

Spaeth, Andrea M.; Dinges, David F.; Goel, Namni

2015-01-01

Short sleep duration is a risk factor for increased hunger and caloric intake, late-night eating, attenuated fat loss when dieting, and for weight gain and obesity. It is unknown whether altered energy-balance responses to sleep loss are stable (phenotypic) over time, and the extent to which individuals differ in vulnerability to such responses. Healthy adults experienced two laboratory exposures to sleep restriction separated by 60–2132 days. Caloric intake, meal timing and weight were objectively measured. Although there were substantial phenotypic differences among participants in weight gain, increased caloric intake, and late-night eating and fat intake, responses within participants showed stability across sleep restriction exposures. Weight change was consistent in both normal-weight and overweight adults. Weight change and increased caloric intake were more stable in men whereas late-night eating was consistent in both genders. This is the first evidence of phenotypic differential vulnerability and trait-like stability of energy balance responses to repeated sleep restriction, underscoring the need for biomarkers and countermeasures to predict and mitigate this vulnerability. PMID:26446681

Phenotypic vulnerability of energy balance responses to sleep loss in healthy adults.

PubMed

Spaeth, Andrea M; Dinges, David F; Goel, Namni

2015-10-08

Short sleep duration is a risk factor for increased hunger and caloric intake, late-night eating, attenuated fat loss when dieting, and for weight gain and obesity. It is unknown whether altered energy-balance responses to sleep loss are stable (phenotypic) over time, and the extent to which individuals differ in vulnerability to such responses. Healthy adults experienced two laboratory exposures to sleep restriction separated by 60-2132 days. Caloric intake, meal timing and weight were objectively measured. Although there were substantial phenotypic differences among participants in weight gain, increased caloric intake, and late-night eating and fat intake, responses within participants showed stability across sleep restriction exposures. Weight change was consistent in both normal-weight and overweight adults. Weight change and increased caloric intake were more stable in men whereas late-night eating was consistent in both genders. This is the first evidence of phenotypic differential vulnerability and trait-like stability of energy balance responses to repeated sleep restriction, underscoring the need for biomarkers and countermeasures to predict and mitigate this vulnerability.

The Emerging Field of Human Social Genomics

PubMed Central

Slavich, George M.; Cole, Steven W.

2013-01-01

Although we generally experience our bodies as being biologically stable across time and situations, an emerging field of research is demonstrating that external social conditions, especially our subjective perceptions of those conditions, can influence our most basic internal biological processes—namely, the expression of our genes. This research on human social genomics has begun to identify the types of genes that are subject to social-environmental regulation, the neural and molecular mechanisms that mediate the effects of social processes on gene expression, and the genetic polymorphisms that moderate individual differences in genomic sensitivity to social context. The molecular models resulting from this research provide new opportunities for understanding how social and genetic factors interact to shape complex behavioral phenotypes and susceptibility to disease. This research also sheds new light on the evolution of the human genome and challenges the fundamental belief that our molecular makeup is relatively stable and impermeable to social-environmental influence. PMID:23853742

Heterogeneous network promotes species coexistence: metapopulation model for rock-paper-scissors game.

PubMed

Nagatani, Takashi; Ichinose, Genki; Tainaka, Kei-Ichi

2018-05-04

Understanding mechanisms of biodiversity has been a central question in ecology. The coexistence of three species in rock-paper-scissors (RPS) systems are discussed by many authors; however, the relation between coexistence and network structure is rarely discussed. Here we present a metapopulation model for RPS game. The total population is assumed to consist of three subpopulations (nodes). Each individual migrates by random walk; the destination of migration is randomly determined. From reaction-migration equations, we obtain the population dynamics. It is found that the dynamic highly depends on network structures. When a network is homogeneous, the dynamics are neutrally stable: each node has a periodic solution, and the oscillations synchronize in all nodes. However, when a network is heterogeneous, the dynamics approach stable focus and all nodes reach equilibriums with different densities. Hence, the heterogeneity of the network promotes biodiversity.

Parent and Peer Links to Trajectories of Anxious Withdrawal From Grades 5 to 8

PubMed Central

Booth-LaForce, Cathryn; Oh, Wonjung; Kennedy, Amy E.; Rubin, Kenneth H.; Rose-Krasnor, Linda; Laursen, Brett

2013-01-01

Individual differences in trajectories of anxious withdrawal were examined from Grades 5 to 8 across the transition to middle school in a community sample (N = 283), using General Growth Mixture Modeling. Three distinct pathways of anxious withdrawal were identified: low-stable (78%), high-decreasing (12%), and high-increasing (10%). In Grade 6, relative to the low-stable class, greater peer exclusion and more free time spent with mother predicted membership in the high-decreasing class; higher peer exclusion predicted membership in the high-increasing class. Within the high-increasing class, the growth of anxious withdrawal was predicted by lower parental autonomy-granting, less free time with mother, both nurturing and restrictive parenting, and greater peer exclusion. Results highlight the role of both parent–child relationship and peer difficulties in increasing the adjustment risk among youth who are anxiously withdrawn prior to the middle-school transition. PMID:22417188

Inter-individual Differences in the Effects of Aircraft Noise on Sleep Fragmentation.

PubMed

McGuire, Sarah; Müller, Uwe; Elmenhorst, Eva-Maria; Basner, Mathias

2016-05-01

Environmental noise exposure disturbs sleep and impairs recuperation, and may contribute to the increased risk for (cardiovascular) disease. Noise policy and regulation are usually based on average responses despite potentially large inter-individual differences in the effects of traffic noise on sleep. In this analysis, we investigated what percentage of the total variance in noise-induced awakening reactions can be explained by stable inter-individual differences. We investigated 69 healthy subjects polysomnographically (mean ± standard deviation 40 ± 13 years, range 18-68 years, 32 male) in this randomized, balanced, double-blind, repeated measures laboratory study. This study included one adaptation night, 9 nights with exposure to 40, 80, or 120 road, rail, and/or air traffic noise events (including one noise-free control night), and one recovery night. Mixed-effects models of variance controlling for reaction probability in noise-free control nights, age, sex, number of noise events, and study night showed that 40.5% of the total variance in awakening probability and 52.0% of the total variance in EEG arousal probability were explained by inter-individual differences. If the data set was restricted to nights (4 exposure nights with 80 noise events per night), 46.7% of the total variance in awakening probability and 57.9% of the total variance in EEG arousal probability were explained by inter-individual differences. The results thus demonstrate that, even in this relatively homogeneous, healthy, adult study population, a considerable amount of the variance observed in noise-induced sleep disturbance can be explained by inter-individual differences that cannot be explained by age, gender, or specific study design aspects. It will be important to identify those at higher risk for noise induced sleep disturbance. Furthermore, the custom to base noise policy and legislation on average responses should be re-assessed based on these findings. © 2016 Associated Professional Sleep Societies, LLC.

Caffeine Citrate Dosing Adjustments to Assure Stable Caffeine Concentrations in Preterm Neonates.

PubMed

Koch, Gilbert; Datta, Alexandre N; Jost, Kerstin; Schulzke, Sven M; van den Anker, John; Pfister, Marc

2017-12-01

To identify dosing strategies that will assure stable caffeine concentrations in preterm neonates despite changing caffeine clearance during the first 8 weeks of life. A 3-step simulation approach was used to compute caffeine doses that would achieve stable caffeine concentrations in the first 8 weeks after birth: (1) a mathematical weight change model was developed based on published weight distribution data; (2) a pharmacokinetic model was developed based on published models that accounts for individual body weight, postnatal, and gestational age on caffeine clearance and volume of distribution; and (3) caffeine concentrations were simulated for different dosing regimens. A standard dosing regimen of caffeine citrate (using a 20 mg/kg loading dose and 5 mg/kg/day maintenance dose) is associated with a maximal trough caffeine concentration of 15 mg/L after 1 week of treatment. However, trough concentrations subsequently exhibit a clinically relevant decrease because of increasing clearance. Model-based simulations indicate that an adjusted maintenance dose of 6 mg/kg/day in the second week, 7 mg/kg/day in the third to fourth week and 8 mg/kg/day in the fifth to eighth week assures stable caffeine concentrations with a target trough concentration of 15 mg/L. To assure stable caffeine concentrations during the first 8 weeks of life, the caffeine citrate maintenance dose needs to be increased by 1 mg/kg every 1-2 weeks. These simple adjustments are expected to maintain exposure to stable caffeine concentrations throughout this important developmental period and might enhance both the short- and long-term beneficial effects of caffeine treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of different lower-limb sensory stimulation strategies on postural regulation—A systematic review and meta-analysis

PubMed Central

Davids, Keith; Liukkonen, Jarmo; Orth, Dominic; Chow, Jia Yi; Jaakkola, Timo

2017-01-01

Systematic reviews of balance control have tended to only focus on the effects of single lower-limb stimulation strategies, and a current limitation is the lack of comparison between different relevant stimulation strategies. The aim of this systematic review and meta-analysis was to examine evidence of effects of different lower-limb sensory stimulation strategies on postural regulation and stability. Moderate- to high- pooled effect sizes (Unbiased (Hedges’ g) standardized mean differences (SMD) = 0.31–0.66) were observed with the addition of noise in a Stochastic Resonance Stimulation Strategy (SRSS), in three populations (i.e., healthy young adults, older adults, and individuals with lower-limb injuries), and under different task constraints (i.e., unipedal, bipedal, and eyes open). A Textured Material Stimulation Strategy (TMSS) enhanced postural control in the most challenging condition—eyes-closed on a stable surface (SMD = 0.61), and in older adults (SMD = 0.30). The Wearable Garments Stimulation Strategy (WGSS) showed no or adverse effects (SMD = -0.68–0.05) under all task constraints and in all populations, except in individuals with lower-limb injuries (SMD = 0.20). Results of our systematic review and meta-analysis revealed that future research could consider combining two or more stimulation strategies in intervention treatments for postural regulation and balance problems, depending on individual needs. PMID:28355265

The plasticity of intellectual development: insights from preventive intervention.

PubMed

Ramey, C T; Yeates, K O; Short, E J

1984-10-01

Debates regarding the plasticity of intelligence are often fired by a confusion between 2 distinct realms of development, that is, between developmental functions (e.g., a group's average IQ over time) and individual differences (e.g., the relative rank ordering of individual IQs within a group). Questions concerning the stability of these 2 realms are statistically independent. Thus there are 2 kinds of intellectual plasticity, and there may be no developmental convergences between them. In the present study, data from an early intervention program were used to investigate the 2 kinds of plasticity separately and to examine certain possible convergences between them. The program involved children at risk for developmental retardation who were randomly assigned at birth to 2 rearing conditions (i.e., educational daycare vs. no educational intervention) and whose intellectual development was then studied longitudinally to 4 years of age. Our findings indicate that developmental functions are moderately alterable through systemic early education, particularly after infancy, whereas individual differences are moderately stable, again particularly after infancy. They also indicate that the 2 kinds of plasticity are independent; the alteration of developmental functions through daycare affects neither the stability nor the determinants of individual differences. We discuss the implications that these findings have for current models of mental development, for the nature-nurture debate, and for arguments concerning the efficacy of early intervention programs.

Recombinant human G6PD for quality control and quality assurance of novel point-of-care diagnostics for G6PD deficiency.

PubMed

Kahn, Maria; LaRue, Nicole; Zhu, Changcheng; Pal, Sampa; Mo, Jack S; Barrett, Lynn K; Hewitt, Steve N; Dumais, Mitchell; Hemmington, Sandra; Walker, Adrian; Joynson, Jeff; Leader, Brandon T; Van Voorhis, Wesley C; Domingo, Gonzalo J

2017-01-01

A large gap for the support of point-of-care testing is the availability of reagents to support quality control (QC) of diagnostic assays along the supply chain from the manufacturer to the end user. While reagents and systems exist to support QC of laboratory screening tests for glucose-6-phosphate dehydrogenase (G6PD) deficiency, they are not configured appropriately to support point-of-care testing. The feasibility of using lyophilized recombinant human G6PD as a QC reagent in novel point-of-care tests for G6PD deficiency is demonstrated. Human recombinant G6PD (r-G6PD) was expressed in Escherichia coli and purified. Aliquots were stored at -80°C. Prior to lyophilization, aliquots were thawed, and three concentrations of r-G6PD (representing normal, intermediate, and deficient clinical G6PD levels) were prepared and mixed with a protective formulation, which protects the enzyme activity against degradation from denaturation during the lyophilization process. Following lyophilization, individual single-use tubes of lyophilized r-G6PD were placed in individual packs with desiccants and stored at five temperatures for one year. An enzyme assay for G6PD activity was used to ascertain the stability of r-G6PD activity while stored at different temperatures. Lyophilized r-G6PD is stable and can be used as a control indicator. Results presented here show that G6PD activity is stable for at least 365 days when stored at -80°C, 4°C, 30°C, and 45°C. When stored at 55°C, enzyme activity was found to be stable only through day 28. Lyophilized r-G6PD enzyme is stable and can be used as a control for point-of-care tests for G6PD deficiency.

Allo-allo-triploid Sphagnum × falcatulum: single individuals contain most of the Holantarctic diversity for ancestrally indicative markers.

PubMed

Karlin, Eric F; Smouse, Peter E

2017-08-01

Allopolyploids exhibit both different levels and different patterns of genetic variation than are typical of diploids. However, scant attention has been given to the partitioning of allelic information and diversity in allopolyploids, particularly that among homeologous monoploid components of the hologenome. Sphagnum × falcatulum is a double allopolyploid peat moss that spans a considerable portion of the Holantarctic. With monoploid genomes from three ancestral species, this organism exhibits a complex evolutionary history involving serial inter-subgeneric allopolyploidizations. Studying populations from three disjunct regions [South Island (New Zealand); Tierra de Fuego archipelago (Chile, Argentina); Tasmania (Australia)], allelic information for five highly stable microsatellite markers that differed among the three (ancestral) monoploid genomes was examined. Using Shannon information and diversity measures, the holoploid information, as well as the information within and among the three component monoploid genomes, was partitioned into separate components for individuals within and among populations and regions, and those information components were then converted into corresponding diversity measures. The majority (76 %) of alleles detected across these five markers are most likely to have been captured by hybridization, but the information within each of the three monoploid genomes varied, suggesting a history of recurrent allopolyploidization between ancestral species containing different levels of genetic diversity. Information within individuals, equivalent to the information among monoploid genomes (for this dataset), was relatively stable, and represented 83 % of the grand total information across the Holantarctic, with both inter-regional and inter-population diversification each accounting for about 5 % of the total information. Sphagnum × falcatulum probably inherited the great majority of its genetic diversity at these markers by reticulation, rather than by subsequent evolutionary radiation. However, some post-hybridization genetic diversification has become fixed in at least one regional population. Methodology allowing statistical analysis of any ploidy level is presented. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Stable Chimeras and Independently Synchronizable Clusters

NASA Astrophysics Data System (ADS)

Cho, Young Sul; Nishikawa, Takashi; Motter, Adilson E.

2017-08-01

Cluster synchronization is a phenomenon in which a network self-organizes into a pattern of synchronized sets. It has been shown that diverse patterns of stable cluster synchronization can be captured by symmetries of the network. Here, we establish a theoretical basis to divide an arbitrary pattern of symmetry clusters into independently synchronizable cluster sets, in which the synchronization stability of the individual clusters in each set is decoupled from that in all the other sets. Using this framework, we suggest a new approach to find permanently stable chimera states by capturing two or more symmetry clusters—at least one stable and one unstable—that compose the entire fully symmetric network.

Relationships between mercury concentration and food selectivity of many kinds of fishes in Minamata Bay

NASA Astrophysics Data System (ADS)

Mori, K.; Kanaya, G.

2016-02-01

Serious injuries occurred in residents who consumed fish and shellfishes in Minamata Bay polluted by high-concentration methyl-mercury in the 1950s. Pollution has fallen to a safe level because of the pollution prevention project (dredging etc.) carried out from 1977 to 1990. From 2010 we have been researching the bioaccumulation of mercury in several fishes in Minamata Bay and surrounding areas. We selected several sampling points that showed different environmental conditions, species composition and food web patterns. For the determination of feeding types of 60 species fishes (600 samples) sampled by gill net, we measured mercury levels of each sample and directly checked food items in gut, and distinguished carnivore, omnivore, herbivore and detritivore. At this time, we introduced a stable isotope analysis for checking the food history and feeding habits of dominant fish. In about 300 individuals of 30 species of dominant fish selected from the 600 samples, we measured the stable nitrogen and carbon isotope ratios (δ15N, δ13C) of each sample. Checking the food items in gut of fishes, more than 80% of fishes were carnivorous, and showed different selectivity of food items, such as fish, crustacean and so on. From the results of stable isotope ratios, benthic fish tended to show a higher ratio of δ13C. Usually benthic microalgae evidenced a higher ratio of δ13C than planktonic microalgae, and the ratio conservative through the food chain. In general, δ15N increases through the food chain with +3 to +4 ‰ enrichment per trophic step. In these data, carnivorous fishes of benthic and pelagic type showed medium and high ratios of δ15N. From comparing the stable isotope ratio to the mercury concentration of fishes, all of the high-mercury fishes belonged to benthic and carnivorous types. We consider the joint method of food web analysis and stable isotope analysis to be useful for understanding the mechanism of mercury bioaccumulation through the food web

Prevalence and prognostic significance of adrenergic escape during chronic beta-blocker therapy in chronic heart failure.

PubMed

Frankenstein, Lutz; Zugck, Christian; Schellberg, Dieter; Nelles, Manfred; Froehlich, Hanna; Katus, Hugo; Remppis, Andrew

2009-02-01

Like aldosterone escape to ACE-inhibitors, adrenergic escape (AE) to beta-blockers appears conceivable in chronic heart failure (CHF), as generalized systemic neurohumoral activation has been described as the pathophysiological basis of this syndrome. The aim of this study was to examine the prevalence and prognostic value of AE with respect to different beta-blocker agents and doses. This was a prospective, observational study of 415 patients with systolic CHF receiving chronic stable beta-blocker therapy. AE was defined by norepinephrine levels above the upper limit of normal. Irrespective of the individual beta-blocker agents used and the dose equivalent taken, the prevalence of AE was 31-39%. Norepinephrine levels neither correlated with heart rate (r=0.02; 95% CI: -0.08-0.11; P=0.74) nor were they related to underlying rhythm (P=0.09) or the individual beta-blocker agent used (P=0.87). The presence of AE was a strong and independent indicator of mortality (adjusted HR: 1.915; 95% CI: 1.387-2.645; chi2: 15.60). We verified the presence of AE in CHF patients on chronic stable beta-blocker therapy, irrespective of the individual beta-blocker agent and the dose equivalent. As AE might indicate therapeutic failure, the determination of AE could help to identify those patients with CHF that might benefit from more aggressive treatment modalities. Heart rate, however, is not a surrogate for adrenergic escape.

Prevalence and prognostic significance of adrenergic escape during chronic β-blocker therapy in chronic heart failure

PubMed Central

Frankenstein, Lutz; Zugck, Christian; Schellberg, Dieter; Nelles, Manfred; Froehlich, Hanna; Katus, Hugo; Remppis, Andrew

2009-01-01

Aims Like aldosterone escape to ACE-inhibitors, adrenergic escape (AE) to β-blockers appears conceivable in chronic heart failure (CHF), as generalized systemic neurohumoral activation has been described as the pathophysiological basis of this syndrome. The aim of this study was to examine the prevalence and prognostic value of AE with respect to different β-blocker agents and doses. Methods and results This was a prospective, observational study of 415 patients with systolic CHF receiving chronic stable β-blocker therapy. AE was defined by norepinephrine levels above the upper limit of normal. Irrespective of the individual β-blocker agents used and the dose equivalent taken, the prevalence of AE was 31–39%. Norepinephrine levels neither correlated with heart rate (r = 0.02; 95% CI: −0.08–0.11; P = 0.74) nor were they related to underlying rhythm (P = 0.09) or the individual β-blocker agent used (P = 0.87). The presence of AE was a strong and independent indicator of mortality (adjusted HR: 1.915; 95% CI: 1.387–2.645; χ2: 15.60). Conclusion We verified the presence of AE in CHF patients on chronic stable β-blocker therapy, irrespective of the individual β-blocker agent and the dose equivalent. As AE might indicate therapeutic failure, the determination of AE could help to identify those patients with CHF that might benefit from more aggressive treatment modalities. Heart rate, however, is not a surrogate for adrenergic escape. PMID:19168516

Use of Shark Dental Protein to Estimate Trophic Position via Amino Acid Compound-Specific Isotope Analysis

NASA Astrophysics Data System (ADS)

Hayes, M.; Herbert, G.; Ellis, G.

2017-12-01

The diets of apex predators such as sharks are expected to change in response to overfishing of their mesopredator prey, but pre-anthropogenic baselines necessary to test for such changes are lacking. Stable isotope analysis (SIA) of soft tissues is commonly used to study diets in animals based on the bioaccumulation of heavier isotopes of carbon and nitrogen with increasing trophic level. In specimens representing pre-anthropogenic baselines, however, a modified SIA approach is needed to deal with taphonomic challenges, such as loss of soft tissues or selective loss of less stable amino acids (AAs) in other sources of organic compounds (e.g., teeth or bone) which can alter bulk isotope values. These challenges can be overcome with a compound-specific isotope analysis of individual AAs (AA-CSIA), but this first requires a thorough understanding of trophic enrichment factors for individual AAs within biomineralized tissues. In this study, we compare dental and muscle proteins of individual sharks via AA-CSIA to determine how trophic position is recorded within teeth and whether that information differs from that obtained from soft tissues. If skeletal organics reliably record information about shark ecology, then archaeological and perhaps paleontological specimens can be used to investigate pre-anthropogenic ecosystems. Preliminary experiments show that the commonly used glutamic acid/phenylalanine AA pairing may not be useful for establishing trophic position from dental proteins, but that estimated trophic position determined from alternate AA pairs are comparable to those from muscle tissue within the same species.

The stability and predictors of peer group deviance in university students

PubMed Central

Myers, John; Dick, Danielle

2015-01-01

Background Peer group deviance (PGD) is strongly associated with current and future externalizing behaviors. Debate remains about the degree to which this association arises from social selection. The first year of university constitutes a social experiment in which most individuals leave their home environment and recreate for themselves a new peer group. Methods PGD was measured in newly arrived university students and then 6 and 18 months later. Other personality and family traits were also assessed. Results PGD reported for high school friends at the start of university and university friends 6 months later were substantially correlated (+0.60). This correlation was only slightly diminished if restricted to students whose home was greater than 50 miles from the university. PGD was strongly predicted across three cohorts by male sex (+), extraversion (+), conscientiousness (−), a family history of alcohol use disorders (+) and depression (+), and religiosity (−). These predictors of PGD had a relatively stable impact over 18 months and, aside from sex, differed only modestly in males and females. Conclusions As individuals change social groups from high school to university, the level of PGD remains relatively stable, suggesting that individuals play a strong role in selecting peer groups with consistent characteristics. PGD is also predicted cross-sectionally and longitudinally by personality, family background and religiosity. Our results suggest that the association between personal and peer deviance is due at least in part to the effects of social selection. PMID:25702166

Dose reconstruction for individuals exposed to ionizing radiation using chromosome painting

NASA Technical Reports Server (NTRS)

Lucas, J. N.; Cox, A. B. (Principal Investigator)

1997-01-01

To be most useful, a biomarker for dose reconstruction should employ an end point that is highly quantitative, stable with time and easily measured. Reciprocal translocations have been shown to be a promising biomarker that is linked to both prior exposure and risk, and they can be measured easily and quantitatively using fluorescence in situ hybridization. In contrast to other biomarkers that are available, the frequency of reciprocal translocations in individuals exposed to whole-body radiation is stable with time after exposure, has rather small interindividual variability and can be measured accurately at low levels of exposure. Results from recent studies demonstrate that measurements of reciprocal translocation frequencies, facilitated by chromosome painting, can be used to reconstruct radiation dose for individuals exposed in the distant past.

Population aging through survival of the fit and stable

NASA Astrophysics Data System (ADS)

Brotto, Tommaso; Bunin, Guy; Kurchan, Jorge

2016-03-01

Motivated by the wide range of known self-replicating systems, some far from genetics, we study a system composed by individuals having an internal dynamics with many possible states that are partially stable, with varying mutation rates. Individuals reproduce and die with a rate that is a property of each state, not necessarily related to its stability, and the offspring is born on the parent’s state. The total population is limited by resources or space, as for example in a chemostat or a Petri dish. Our aim is to show that mutation rate and fitness become more correlated, even if they are completely uncorrelated for an isolated individual, underlining the fact that the interaction induced by limitation of resources is by itself efficient for generating collective effects.

Dose reconstruction for individuals exposed to ionizing radiation using chromosome painting.

PubMed

Lucas, J N

1997-11-01

To be most useful, a biomarker for dose reconstruction should employ an end point that is highly quantitative, stable with time and easily measured. Reciprocal translocations have been shown to be a promising biomarker that is linked to both prior exposure and risk, and they can be measured easily and quantitatively using fluorescence in situ hybridization. In contrast to other biomarkers that are available, the frequency of reciprocal translocations in individuals exposed to whole-body radiation is stable with time after exposure, has rather small interindividual variability and can be measured accurately at low levels of exposure. Results from recent studies demonstrate that measurements of reciprocal translocation frequencies, facilitated by chromosome painting, can be used to reconstruct radiation dose for individuals exposed in the distant past.

Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki)

PubMed Central

Drago, Massimiliano; Franco-Trecu, Valentina; Cardona, Luis; Inchausti, Pablo; Tapia, Washington; Páez-Rosas, Diego

2016-01-01

Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ13C and δ15N) of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months), resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years), may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago. PMID:26808381

Discrimination Factors and Incorporation Rates for Organic Matrix in Shark Teeth Based on a Captive Feeding Study.

PubMed

Zeichner, S S; Colman, A S; Koch, P L; Polo-Silva, C; Galván-Magaña, F; Kim, S L

Sharks migrate annually over large distances and occupy a wide variety of habitats, complicating analysis of lifestyle and diet. A biogeochemical technique often used to reconstruct shark diet and environment preferences is stable isotope analysis, which is minimally invasive and integrates through time and space. There are previous studies that focus on isotopic analysis of shark soft tissues, but there are limited applications to shark teeth. However, shark teeth offer an advantage of multiple ecological snapshots and minimum invasiveness during removal because of their distinct conveyor belt tooth replacement system. In this study, we analyze δ 13 C and δ 15 N values of the organic matrix in leopard shark teeth (Triakis semifasciata) from a captive experiment and report discrimination factors as well as incorporation rates. We found differences in tooth discrimination factors for individuals fed different prey sources (mean ± SD; Δ 13 C squid = 4.7‰ ± 0.5‰, Δ 13 C tilapia = 3.1‰ ± 1.0‰, Δ 15 N squid = 2.0‰ ± 0.7‰, Δ 15 N tilapia = 2.8‰ ± 0.6‰). In addition, these values differed from previously published discrimination factors for plasma, red blood cells, and muscle of the same leopard sharks. Incorporation rates of shark teeth were similar for carbon and nitrogen (mean ± SE; λ C = 0.021 ± 0.009, λ N = 0.024 ± 0.007) and comparable to those of plasma. We emphasize the difference in biological parameters on the basis of tissue substrate and diet items to interpret stable isotope data and apply our results to stable isotope values from blue shark (Prionace glauca) teeth to illustrate the importance of biological parameters to interpret the complex ecology of a migratory shark.

The role of stable housing as a determinant of poverty-related quality of life in vulnerable individuals.

PubMed

Baumstarck, Karine; Boyer, Laurent; Auquier, Pascal

2015-10-01

The aim of this study was to identify potential socio-demographic and socio-economic determinants associated with quality of life (QoL) in impoverished individuals admitted in emergency departments (EDs) using a self-administered multidimensional poverty-related QoL questionnaire (PQoL) and a generic QoL questionnaire (Duke). cross-sectional study. Ten EDs in France. All participants included in this study lived in impoverished conditions. We collected socio-demographic information, economic data, and data related to the ED visit. Multiple linear regressions were performed to determine which variables were linked to QoL scores. Three-hundred and eighty-seven individuals were enrolled, and 378 (98%) responded to the QoL questionnaires. PQoL was significantly lower for single individuals (β from -0.15 to -0.23), without a stable home (β from -0.17 to -0.34) and individuals without general health coverage (β = 0.20). Compared with men, women reported lower scores in the psychological well-being dimension (β = -0.19) and higher scores in the relationships with friends dimension (β = 0.17). Not having stable housing was the most important factor associated with low QoL in impoverished people. This finding demonstrates the need for support from policymakers at the national and local levels for these vulnerable populations. © The Author 2015. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved.

Inter-individual Differences in the Effects of Aircraft Noise on Sleep Fragmentation

PubMed Central

McGuire, Sarah; Müller, Uwe; Elmenhorst, Eva-Maria; Basner, Mathias

2016-01-01

Study Objectives: Environmental noise exposure disturbs sleep and impairs recuperation, and may contribute to the increased risk for (cardiovascular) disease. Noise policy and regulation are usually based on average responses despite potentially large inter-individual differences in the effects of traffic noise on sleep. In this analysis, we investigated what percentage of the total variance in noise-induced awakening reactions can be explained by stable inter-individual differences. Methods: We investigated 69 healthy subjects polysomnographically (mean ± standard deviation 40 ± 13 years, range 18–68 years, 32 male) in this randomized, balanced, double-blind, repeated measures laboratory study. This study included one adaptation night, 9 nights with exposure to 40, 80, or 120 road, rail, and/or air traffic noise events (including one noise-free control night), and one recovery night. Results: Mixed-effects models of variance controlling for reaction probability in noise-free control nights, age, sex, number of noise events, and study night showed that 40.5% of the total variance in awakening probability and 52.0% of the total variance in EEG arousal probability were explained by inter-individual differences. If the data set was restricted to nights (4 exposure nights with 80 noise events per night), 46.7% of the total variance in awakening probability and 57.9% of the total variance in EEG arousal probability were explained by inter-individual differences. The results thus demonstrate that, even in this relatively homogeneous, healthy, adult study population, a considerable amount of the variance observed in noise-induced sleep disturbance can be explained by inter-individual differences that cannot be explained by age, gender, or specific study design aspects. Conclusions: It will be important to identify those at higher risk for noise induced sleep disturbance. Furthermore, the custom to base noise policy and legislation on average responses should be re-assessed based on these findings. Citation: McGuire S, Müller U, Elmenhorst EM, Basner M. Inter-individual differences in the effects of aircraft noise on sleep fragmentation. SLEEP 2016;39(5):1107–1110. PMID:26856901

Change in Work-Time Control and Work-Home Interference Among Swedish Working Men and Women: Findings from the SLOSH Cohort Study.

PubMed

Leineweber, Constanze; Kecklund, Göran; Lindfors, Petra; Magnusson Hanson, Linda L

2016-12-01

The aim is to study the influence of change in work-time control (WTC) on work-home interference (WHI) while adjusting for other work-related factors, demographics, changes at work and WHI at baseline among women and men. An additional aim was to explore sex differences in the relation between change in WTC and WHI. The study included working participants of the Swedish Longitudinal Occupational Survey of Health (SLOSH) study of the third (2010) and fourth (2012) waves (n = 5440). Based on a seven-item index, four groups of WTC were formed: stable high (40 %), stable low (42 %), increasing (9 %), or decreasing (9 %) WTC over the 2 years. WHI was measured by four items and individuals were categorised in whether suffering or not suffering of WHI. Sex-stratified logistic regression analyses with 95 % confidence intervals (CI) were used to estimate the odds of experiencing WHI by change in WTC. Controlling for demographics and work-related factors, women with stable low (OR = 1.46; 95 % CI 1.14-1.88) and women and men with decreasing WTC (women OR = 1.99; 95 % CI 1.38-2.85; men OR = 1.80; 95 % CI 1.18-2.73) had higher odds of WHI than those with a stable high WTC. Additionally, adjusting for changes at work and WHI at baseline did not alter the results substantially. Interaction analysis did not reveal any significant sex difference in the relation between WTC and WHI. For both women and men decreased and for women only, low control over working hours resulted in WHI also after adjusting for work-related factors and demographics.

Psychosocial work conditions, social participation and social capital: a causal pathway investigated in a longitudinal study.

PubMed

Lindström, Martin

2006-01-01

Social capital is often claimed to be promoted by stable social structures such as low migration rates between neighbourhoods and social networks that remain stable over time. However, stable social structures may also inhibit the formation of social capital in the form of social networks and social participation. One example is psychosocial conditions at work, which may be determined by characteristics such as demand and control in the work situation. The study examines the active workforce subpopulation within the Swedish Malmö Shoulder Neck Study. A total of 7836 individuals aged 45-69 years, were interviewed at baseline between 1992 and 1994, and at a 1-year follow-up. Four groups of baseline psychosocial work conditions categories defined by the Karasek-Theorell model (jobstrain, passive, active, relaxed) were analysed according to 13 different social participation items during the past year reported at the 1-year follow-up. Odds ratios and 95% confidence intervals with the jobstrain group as a reference were estimated. A multivariate logistic regression model was used to assess differences in different aspects of social participation between the four psychosocial work conditions groups. The results show that the respondents within the active category in particular but also the relaxed category, have significantly higher participation in many of the 13 social participation items, even after multivariate adjustments. The results strongly suggest that psychosocial work conditions may be an important determinant of social capital measured as social participation, a finding of immediate public health relevance because of the well known positive association between social participation and health-related behaviours.

Topological States in Partially-PT -Symmetric Azimuthal Potentials

NASA Astrophysics Data System (ADS)

Kartashov, Yaroslav V.; Konotop, Vladimir V.; Torner, Lluis

2015-11-01

We introduce partially-parity-time (p PT ) -symmetric azimuthal potentials composed from individual PT -symmetric cells located on a ring, where two azimuthal directions are nonequivalent in a sense that in such potential excitations carrying topological dislocations exhibit different dynamics for different directions of energy circulation in the initial field distribution. Such nonconservative ratchetlike structures support rich families of stable vortex solitons in cubic nonlinear media, whose properties depend on the sign of the topological charge due to the nonequivalence of azimuthal directions. In contrast, oppositely charged vortex solitons remain equivalent in similar fully-P T -symmetric potentials. The vortex solitons in the p P T - and P T -symmetric potentials are shown to feature qualitatively different internal current distributions, which are described by different discrete rotation symmetries of the intensity profiles.

The Effect of Parasite Infection on Stable Isotope Turnover Rates of δ15N, δ13C and δ34S in Multiple Tissues of Eurasian Perch Perca fluviatilis.

PubMed

Yohannes, Elizabeth; Grimm, Claudia; Rothhaupt, Karl-Otto; Behrmann-Godel, Jasminca

2017-01-01

Stable isotope analysis of commercially and ecologically important fish can improve understanding of life-history and trophic ecology. However, accurate interpretation of stable isotope values requires knowledge of tissue-specific isotopic turnover that will help to describe differences in the isotopic composition of tissues and diet. We performed a diet-switch experiment using captive-reared parasite-free Eurasian perch (Perca fluviatilis) and wild caught specimens of the same species, infected with the pike tapeworm Triaenophorus nodulosus living in host liver tissue. We hypothesize that metabolic processes related to infection status play a major role in isotopic turnover and examined the influence of parasite infection on isotopic turn-over rate of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) in liver, blood and muscle. The δ15N and δ13C turnovers were fastest in liver tissues, followed by blood and muscle. In infected fish, liver and blood δ15N and δ13C turnover rates were similar. However, in infected fish, liver and blood δ13C turnover was faster than that of δ15N. Moreover, in infected subjects, liver δ15N and δ13C turnover rates were three to five times faster than in livers of uninfected subjects (isotopic half-life of ca.3-4 days compared to 16 and 10 days, respectively). Blood δ34S turnover rate were about twice faster in non-infected individuals implying that parasite infection could retard the turnover rate of δ34S and sulphur containing amino acids. Slower turnover rate of essential amino acid could probably decrease individual immune function. These indicate potential hidden costs of chronic and persistent infections that may have accumulated adverse effects and might eventually impair life-history fitness. For the first time, we were able to shift the isotope values of parasites encapsulated in the liver by changing the dietary source of the host. We also report variability in isotopic turnover rates between tissues, elements and between infected and parasite-free individuals. These results contribute to our understanding of data obtained from field and commercial hatcheries; and strongly improve the applicability of the stable isotope method in understanding life-history and trophic ecology of fish populations.

The Effect of Parasite Infection on Stable Isotope Turnover Rates of δ15N, δ13C and δ34S in Multiple Tissues of Eurasian Perch Perca fluviatilis

PubMed Central

Yohannes, Elizabeth; Grimm, Claudia; Rothhaupt, Karl-Otto; Behrmann-Godel, Jasminca

2017-01-01

Stable isotope analysis of commercially and ecologically important fish can improve understanding of life-history and trophic ecology. However, accurate interpretation of stable isotope values requires knowledge of tissue-specific isotopic turnover that will help to describe differences in the isotopic composition of tissues and diet. We performed a diet-switch experiment using captive-reared parasite-free Eurasian perch (Perca fluviatilis) and wild caught specimens of the same species, infected with the pike tapeworm Triaenophorus nodulosus living in host liver tissue. We hypothesize that metabolic processes related to infection status play a major role in isotopic turnover and examined the influence of parasite infection on isotopic turn-over rate of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) in liver, blood and muscle. The δ15N and δ13C turnovers were fastest in liver tissues, followed by blood and muscle. In infected fish, liver and blood δ15N and δ13C turnover rates were similar. However, in infected fish, liver and blood δ13C turnover was faster than that of δ15N. Moreover, in infected subjects, liver δ15N and δ13C turnover rates were three to five times faster than in livers of uninfected subjects (isotopic half-life of ca.3-4 days compared to 16 and 10 days, respectively). Blood δ34S turnover rate were about twice faster in non-infected individuals implying that parasite infection could retard the turnover rate of δ34S and sulphur containing amino acids. Slower turnover rate of essential amino acid could probably decrease individual immune function. These indicate potential hidden costs of chronic and persistent infections that may have accumulated adverse effects and might eventually impair life-history fitness. For the first time, we were able to shift the isotope values of parasites encapsulated in the liver by changing the dietary source of the host. We also report variability in isotopic turnover rates between tissues, elements and between infected and parasite-free individuals. These results contribute to our understanding of data obtained from field and commercial hatcheries; and strongly improve the applicability of the stable isotope method in understanding life-history and trophic ecology of fish populations. PMID:28046021

Trends in health complaints from 2002 to 2010 in 34 countries and their association with health behaviours and social context factors at individual and macro-level.

PubMed

Ottová-Jordan, Veronika; Smith, Otto R F; Augustine, Lilly; Gobina, Inese; Rathmann, Katharina; Torsheim, Torbjørn; Mazur, Joanna; Välimaa, Raili; Cavallo, Franco; Jericek Klanscek, Helena; Vollebergh, Wilma; Meilstrup, Charlotte; Richter, Matthias; Moor, Irene; Ravens-Sieberer, Ulrike

2015-04-01

This article describes trends and stability over time in health complaints in adolescents from 2002 to 2010 and investigates associations between health complaints, behavioural and social contextual factors at individual level and economic factors at macro-level. Comprising N = 510 876 11-, 13- and 15-year-old children and adolescents in Europe, North America and Israel, data came from three survey cycles of the international Health Behaviour in School-aged Children (HBSC) study. Age- and gender-adjusted trends in health complaints were examined in each country by means of linear regression. By using the country as the random effects variable, we tested to what extent individual and contextual variables were associated with health complaints. Significant associations are stronger for individual level determinants (e.g. being bullied, smoking) than for determinants at macro-level (e.g. GDP, Gini), as can be seen by the small effect sizes (less than 5% for different trends). Health complaints are fairly stable over time in most countries, and no clear international trend in health complaints can be observed between 2002 and 2010. The most prominent stable determinants were being female, being bullied, school pressure and smoking. Factors associated with health complaints are more related to the proximal environment than to distal macro-level factors. This points towards intensifying targeted interventions, (e.g. for bullying) and also targeting specific risk groups. The comparably small effect size at country-level indicates that country-level factors have an impact on health and should not be ignored. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Inter- and intra-individual variability in the levels of plasma homovanillic acid in schizophrenic patients.

PubMed

Zumárraga, Mercedes; Dávila, Ricardo; González-Torres, Miguel Angel; Anguiano, Juan B; Zabalo, María José; Basterreche, Nieves; Arrúe, Aurora; Zamalloa, María Isabel; Guimón, José

2007-04-13

Changes in the levels of homovanillic acid in blood plasma (pHVA) may reflect changes which occur in the brain. In healthy individuals, this concentration of pHVA is stable over time. Over the course of one month, we studied 98 acute schizophrenic patients who had not been taking any medication but were administered neuroleptics upon hospital admission, together with 23 chronic schizophrenic patients on long-term treatment from whom medication was withdrawn. Blood samples were taken at regular intervals from each individual and the concentration of plasma homovanillic acid was measured. We found relative stable values of pHVA with an intraclass correlation coefficient of 0.363 in acute patients and 0.638 (p<0.0001) in chronic patients, although no differences were found in mean values (13.79 and 14.18 microg/L, respectively) or in the variation range (7.20 to 26.7 microg/L and 6.96 to 29.96 microg/L respectively). The index of individuality was calculated to be 1.36 in acute patients and 0.74 in chronic patients. Despite the wide range of values in the concentration of pHVA and the presence of pharmacological stimuli, we found a certain reproducibility in the levels of this dopamine metabolite. These findings are consistent with the idea that the dopaminergic activity is characterized by a constitutive value which would be under genetic control. The higher stability observed in chronic patients may reflect a weaker, age-related dopaminergic plasticity; conversely, it may indicate that a lack of plasticity in response to a pharmacological stimulus may be an indicator of poorer prognosis.

Stability of whole brain and regional network topology within and between resting and cognitive states.

PubMed

Rzucidlo, Justyna K; Roseman, Paige L; Laurienti, Paul J; Dagenbach, Dale

2013-01-01

Graph-theory based analyses of resting state functional Magnetic Resonance Imaging (fMRI) data have been used to map the network organization of the brain. While numerous analyses of resting state brain organization exist, many questions remain unexplored. The present study examines the stability of findings based on this approach over repeated resting state and working memory state sessions within the same individuals. This allows assessment of stability of network topology within the same state for both rest and working memory, and between rest and working memory as well. fMRI scans were performed on five participants while at rest and while performing the 2-back working memory task five times each, with task state alternating while they were in the scanner. Voxel-based whole brain network analyses were performed on the resulting data along with analyses of functional connectivity in regions associated with resting state and working memory. Network topology was fairly stable across repeated sessions of the same task, but varied significantly between rest and working memory. In the whole brain analysis, local efficiency, Eloc, differed significantly between rest and working memory. Analyses of network statistics for the precuneus and dorsolateral prefrontal cortex revealed significant differences in degree as a function of task state for both regions and in local efficiency for the precuneus. Conversely, no significant differences were observed across repeated sessions of the same state. These findings suggest that network topology is fairly stable within individuals across time for the same state, but also fluid between states. Whole brain voxel-based network analyses may prove to be a valuable tool for exploring how functional connectivity changes in response to task demands.

Stability and change: Stress responses and the shaping of behavioral phenotypes over the life span.

PubMed

Hennessy, Michael B; Kaiser, Sylvia; Tiedtke, Tobias; Sachser, Norbert

2015-01-01

In mammals, maternal signals conveyed via influences on hypothalamic-pituitary-adrenal (HPA) activity may shape behavior of the young to be better adapted for prevailing environmental conditions. However, the mother's influence extends beyond classic stress response systems. In guinea pigs, several hours (h) of separation from the mother activates not only the HPA axis, but also the innate immune system, which effects immediate behavioral change, as well as modifies behavioral responsiveness in the future. Moreover, the presence of the mother potently suppresses the behavioral consequences of this innate immune activation. These findings raise the possibility that long-term adaptive behavioral change can be mediated by the mother's influence on immune-related activity of her pups. Furthermore, the impact of social partners on physiological stress responses and their behavioral outcomes are not limited to the infantile period. A particularly crucial period for social development in male guinea pigs is that surrounding the attainment of sexual maturation. At this time, social interactions with adults can dramatically affect circulating cortisol concentrations and social behavior in ways that appear to prepare the male to best cope in its likely future social environment. Despite such multiple social influences on the behavior of guinea pigs at different ages, inter-individual differences in the magnitude of the cortisol response remain surprisingly stable over most of the life span. Together, it appears that throughout the life span, physiological stress responses may be regulated by social stimuli. These influences are hypothesized to adjust behavior for predicted environmental conditions. In addition, stable individual differences might provide a means of facilitating adaptation to less predictable conditions.

Individual specialization in the foraging habits of female bottlenose dolphins living in a trophically diverse and habitat rich estuary

USGS Publications Warehouse

Rossman, Sam; Ostrom, Peggy H.; Stolen, Megan; Barros, Nélio B.; Gandhi, Hasand; Stricker, Craig A.; Wells, Randall S.

2015-01-01

We examine individual specialization in foraging habits (foraging habitat and trophic level) of female bottlenose dolphins (Tursiops truncatus) resident in Sarasota Bay, Florida, USA, by analyzing time series of stable isotope (δ15N and δ13C) values in sequential growth layer groups within teeth. The isotope data provide a chronology of foraging habits over the lifetime of the individual and allowed us to show that female bottlenose dolphins exhibit a high degree of individual specialization in both foraging habitat and trophic level. The foraging habits used by adult females are similar to those they used as calves and may be passed down from mother to calf through social learning. We also characterized the foraging habits and home range of each individual by constructing standard ellipses from isotope values and dolphin sightings data (latitude and longitude), respectively. These data show that Sarasota Bay bottlenose dolphins forage within a subset of the habitats in which they are observed. Moreover, females with similar observational standard ellipses often possessed different foraging specializations. Female bottlenose dolphins may demonstrate individual specialization in foraging habits because it reduces some of the cost of living in groups, such as competition for prey.

Valuing the chances of survival of two distinct Eurasian lynx populations in Poland - do people want to keep the doors open?

PubMed

Bartczak, Anna; Meyerhoff, Jürgen

2013-11-15

This study investigates individuals' preferences toward protection programs aimed at increasing the chances of survival of the two distinct Eurasian lynx populations in Poland. Those two groups, the Lowland and the Carpathian population, are exposed to different risks of extinction as they have different numbers, different-sized areas of occupation and different migration possibilities. Using a discrete choice experiment we examine the influence of the initial degree of endangerment on the allocation of respondents' funds. The results show that people prefer to invest in the conservation of the lynx population, which has initially lower chances of survival. The main driver of respondents' choices seems to be loss aversion rather than the urge to invest in an option with an expected higher outcome. This observation can be interpreted as people trying to keep all the options - doors - open by devoting more funds to the more vulnerable population than to the more stable one. Employing a scale-extended latent class model allowed us to detect segments among individuals showing different types of response behavior, including a form of serial non-participation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Design of latex-layered double hydroxide composites by tuning the aggregation in suspensions.

PubMed

Pavlovic, Marko; Rouster, Paul; Bourgeat-Lami, Elodie; Prevot, Vanessa; Szilagyi, Istvan

2017-01-25

Colloidal stability of polymeric latex particles was studied in the presence of oppositely charged layered double hydroxide (LDH) platelets of different interlayer anions. Adsorption of the LDH particles led to charge neutralization and to overcharging of the latex at appropriate concentrations. Mixing stable colloidal suspensions of individual particles results in rapid aggregation once the LDH adsorption neutralizes the negative charges of the polymer spheres, while stable suspensions were observed at high and low LDH doses. The governing interparticle interactions included repulsive electrical double layer forces as well as van der Waals and patch-charge attractions, whose strength depended on the amount of LDH particles adsorbed on the latex surface. The type of the LDH interlayer anions did not affect the colloidal stability of the samples. Structural investigation of the obtained latex-LDH composites revealed that the polymer spheres were completely coated with the inorganic platelets once their concentration was sufficiently high. These results are especially important for designing synthetic routes for hybrid systems in suspensions, where stable colloids are required for uniform film-formation and for the homogeneous distribution of the inorganic filler within the composite materials.

Non-lethal sampling of walleye for stable isotope analysis: a comparison of three tissues

USGS Publications Warehouse

Chipps, Steven R.; VanDeHey, J.A.; Fincel, M.J.

2012-01-01

Stable isotope analysis of fishes is often performed using muscle or organ tissues that require sacrificing animals. Non-lethal sampling provides an alternative for evaluating isotopic composition for species of concern or individuals of exceptional value. Stable isotope values of white muscle (lethal) were compared with those from fins and scales (non-lethal) in walleye, Sander vitreus (Mitchill), from multiple systems, size classes and across a range of isotopic values. Isotopic variability was also compared among populations to determine the potential of non-lethal tissues for diet-variability analyses. Muscle-derived isotope values were enriched compared with fins and depleted relative to scales. A split-sample validation technique and linear regression found that isotopic composition of walleye fins and scales was significantly related to that in muscle tissue for both δ13C and δ15N (r2 = 0.79–0.93). However, isotopic variability was significantly different between tissue types in two of six populations for δ15N and three of six populations for δ13C. Although species and population specific, these findings indicate that isotopic measures obtained from non-lethal tissues are indicative of those obtained from muscle.

Effects of acid washing on stable isotope ratios of C and N in penaeid shrimp and seagrass: Implications for food-web studies using multiple stable isotopes

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

Bunn, S.E.; Kempster, M.A.; Loneragan, N.R.

1995-05-01

We investigated the effects of acid washing on the carbon and nitrogen composition and stable isotope ratios of C and N in shrimp (Metapenaeus spp.) and seagrass (Enhalus acoroides). Acid washing did not affect the mean {delta}{sup 13}C ratios for juvenile Metapenaeus moyebi and resulted in only an ecologically insignificant change (0.3%) in mean {delta}{sup 13}C ratios for larger metapenaeus bennettae. In contrast, acid washing increased the mean {delta}{sup 15}N signatures of shrimp tissue ({approximately}3%) and decreased that of seagrass ({approximately}1.8%) to a degree that may confound the interpretation of food webs. The increase in %C and %N in bothmore » shrimp and seagrass after acid washing suggests that the changes in isotope ratios are due to loss of molecules comparatively low in C and N. Treating samples by acid washing also resulted in an increase in the variation among individuals for both {delta}{sup 15}N and {delta}{sup 13}C, which would lead to a loss of statistical power for testing differences between species, sites, or seasons. 13 refs., 2 figs., 1 tab.« less

Heritable influences on behavioural problems from early childhood to mid-adolescence: evidence for genetic stability and innovation.

PubMed

Lewis, G J; Plomin, R

2015-07-01

Although behavioural problems (e.g., anxiety, conduct, hyperactivity, peer problems) are known to be heritable both in early childhood and in adolescence, limited work has examined prediction across these ages, and none using a genetically informative sample. We examined, first, whether parental ratings of behavioural problems (indexed by the Strengths and Difficulties questionnaire) at ages 4, 7, 9, 12, and 16 years were stable across these ages. Second, we examined the extent to which stability reflected genetic or environmental effects through multivariate quantitative genetic analysis on data from a large (n > 3000) population (UK) sample of monozygotic and dizygotic twins. Behavioural problems in early childhood (age 4 years) showed significant associations with the corresponding behavioural problem at all subsequent ages. Moreover, stable genetic influences were observed across ages, indicating that biological bases underlying behavioural problems in adolescence are underpinned by genetic influences expressed as early as age 4 years. However, genetic and environmental innovations were also observed at each age. These observations indicate that genetic factors are important for understanding stable individual differences in behavioural problems across childhood and adolescence, although novel genetic influences also facilitate change in such behaviours.

[Early attachement relationships and epigenetic customization].

PubMed

Rocchi, Giordana; Serio, Valentina; Carluccio, Giuseppe Mattia; Marini, Isabella; Meuti, Valentina; Zaccagni, Michela; Giacchetti, Nicoletta; Aceti, Franca

2015-01-01

Recently, new findings in epigenetic science switched the focus from the observation of physiological intragenomic dynamics to the idea of an environmental co-construction of phenotypic expression. In psichodynamic field, objectual relations and attachement theoreticians emphasized the interpersonal dimension of individual development, focusing the attention on the relational matrix of self organization. The construction of stable affective-behavioral traits throughout different parenting styles has actually found a coincidence in ethological studies, which have explored the epigenetic processes underlying the relationship between caregiving and HPA stress responsiveness. An adequate parenting style seems to support affective regulation throughout psychobiological hidden moderators, which would tend to rebalance the physiological systems homeostasis; an unconfident attachment style would promote, on the other hand, the allostatic load rise. Sites of longlife epigenetic susceptibility have also been identified in humans; although associated with risk of maladaptive developing in adverse environmental conditions, they seem to confer protection under favorable conditions. This persisting possibility of reorganization of stable traits throughout lifetime, which seems to be activated by a relevant environmental input, grant to significant relationships, and to therapeutical one as well, an implicit reconditioning potential which could result into the configuration of new stable affective-behavioral styles.

[The genetic effects in the somatic cells of persons working under chronic irradiation of different intensities after the accident at the Chernobyl Atomic Electric Power Station].

PubMed

Pilinskaia, M A; Shemetun, A M; Dybskiĭ, S S; Red'ko, D V

1996-01-01

A complex genetic study of two groups from of Chernobyl NPP personnel (from "Shelter" unit and 3rd Block) has been carried out using classical cytogenetic and GPA methods. The first group was the most vulnerable from the viewpoint of accumulated dose (exceeding 25 cGy for the moment of study). Positive correlation between individual and group frequencies of cytogenetic markers of irradiation (stable and unstable chromosomes aberrations) and NO mutations in the GPA locus was found.

Persistence of Space Radiation-Induced Cytogenetic Damage in the Blood Lymphocytes of Astronauts and the Effects of Repeat Long Duration Space Missions

NASA Technical Reports Server (NTRS)

George, Kerry A.; Cucinotta, Francis A.

2009-01-01

The yield of chromosome damage in astronauts blood lymphocytes has been shown to increase after long duration space missions of a few months or more. This provides a useful in vivo measurement of space radiation induced damage that takes into account individual radiosensitivity and considers the influence of microgravity and other stress conditions. We present our latest follow-up analyses of chromosome damage in astronauts blood lymphocytes assessed by fluorescence in situ hybridization (FISH) chromosome painting and collected at various times, from directly after return from space to several years after flight. For most individuals the analysis of individual time-courses for translocations revealed a temporal decline of yields with different half-lives. Dose was derived from frequencies of chromosome exchanges using preflight calibration curves, and estimates derived from samples collected a few days after return to earth lie within the range expected from physical dosimetry. However, a temporal decline in yields may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure. Limited data on three individuals who have participated in repeat long duration space flights indicates a lack of correlation between time in space and translocation yields, and show a possible adaptive response to space radiation exposure.

Four-year prospective evaluation of the relationship between meaning in life and smoking status

PubMed Central

2013-01-01

Background To date, all investigations on the relationship between smoking and perceived level of meaning in life have used cross-sectional designs. Therefore, the purpose of the present prospective study, conducted with a four-year time lag, was to test the predictive power of the life meaning construct concerning changes in smoking status. Methods The data of 4,294 respondents (40.3% male, Mage = 54.7 ± 16.5 yrs) from the Hungarian Epidemiological Panel Survey were analyzed using the Kruskal-Wallis and Mann–Whitney U-test and structural equation modeling (SEM) with a nominal outcome variable. Gender, age, and educational level were included in the study as covariates. Results On the bivariate level, results showed that both baseline and follow-up meaning in life scores were higher in stable non-smokers when compared to stable smokers. However, quitters and starters differed from stable non-smokers in their baseline but not in follow-up life meaning scores. The other relationships (stable smokers vs. quitters; stable smokers vs. starters, starters vs. quitters) were non-significant in both time points. According to the SEM-analysis, a higher sense of meaning in life measured at baseline and follow-up is associated with a lower likelihood (OR = 0.54, z = 2.80, p = 0.005; OR = 0.64, z = 2.88, p = 0.004, respectively) of being a stable smoker compared to being a stable non-smoker, confirming the expected relationship between smoking and decreased level of meaning in life. However, neither baseline nor follow-up life meaning scores predicted significantly quitting and uptake of smoking. Conclusions If future research from other cultures verifies the protective role of a higher level of meaning in life against smoking, then smoking prevention and cessation programs will also have to include such components that help individuals experience more meaning in their lives. PMID:23433067

Complex chromosome aberrations persist in individuals many years after occupational exposure to densely ionizing radiation: an mFISH study.

PubMed

Hande, M Prakash; Azizova, Tamara V; Burak, Ludmilla E; Khokhryakov, Valentin F; Geard, Charles R; Brenner, David J

2005-09-01

Long-lived, sensitive, and specific biomarkers of particular mutagenic agents are much sought after and potentially have broad applications in the fields of cancer biology, epidemiology, and prevention. Many clastogens induce a spectrum of chromosome aberrations, and some of them can be exploited as biomarkers of exposure. Densely ionizing radiation, for example, alpha particle radiation (from radon or plutonium) and neutron radiation, preferentially induces complex chromosome aberrations, which can be detected by the 24-color multifluor fluorescence in situ hybridization (mFISH) technique. We report the detection and quantification of stable complex chromosome aberrations in lymphocytes of healthy former nuclear-weapons workers, who were exposed many years ago to plutonium, gamma rays, or both, at the Mayak weapons complex in Russia. We analyzed peripheral-blood lymphocytes from these individuals for the presence of persistent complex chromosome aberrations. A significantly elevated frequency of complex chromosome translocations was detected in the highly exposed plutonium workers but not in the group exposed only to high doses of gamma radiation. No such differences were found for simple chromosomal aberrations. The results suggest that stable complex chromosomal translocations represent a long-lived, quantitative, low-background biomarker of densely ionizing radiation for human populations exposed many years ago. (c) 2005 Wiley-Liss, Inc.

Incest versus abstinence: reproductive trade-offs between mate limitation and progeny fitness in a self-incompatible invasive plant

PubMed Central

Pierson, Jennifer C; Swain, Stephen M; Young, Andrew G

2013-01-01

Plant mating systems represent an evolutionary and ecological trade-off between reproductive assurance through selfing and maximizing progeny fitness through outbreeding. However, many plants with sporophytic self-incompatibility systems exhibit dominance interactions at the S-locus that allow biparental inbreeding, thereby facilitating mating between individuals that share alleles at the S-locus. We investigated this trade-off by estimating mate availability and biparental inbreeding depression in wild radish from five different populations across Australia. We found dominance interactions among S-alleles increased mate availability relative to estimates based on individuals that did not share S-alleles. Twelve of the sixteen fitness variables were significantly reduced by inbreeding. For all the three life-history phases evaluated, self-fertilized offspring suffered a greater than 50% reduction in fitness, while full-sib and half-sib offspring suffered a less than 50% reduction in fitness. Theory indicates that fitness costs greater than 50% can result in an evolutionary trajectory toward a stable state of self-incompatibility (SI). This study suggests that dominance interactions at the S-locus provide a possible third stable state between SI and SC where biparental inbreeding increases mate availability with relatively minor fitness costs. This strategy allows weeds to establish in new environments while maintaining a functional SI system. PMID:24455137

Incest versus abstinence: reproductive trade-offs between mate limitation and progeny fitness in a self-incompatible invasive plant.

PubMed

Pierson, Jennifer C; Swain, Stephen M; Young, Andrew G

2013-12-01

Plant mating systems represent an evolutionary and ecological trade-off between reproductive assurance through selfing and maximizing progeny fitness through outbreeding. However, many plants with sporophytic self-incompatibility systems exhibit dominance interactions at the S-locus that allow biparental inbreeding, thereby facilitating mating between individuals that share alleles at the S-locus. We investigated this trade-off by estimating mate availability and biparental inbreeding depression in wild radish from five different populations across Australia. We found dominance interactions among S-alleles increased mate availability relative to estimates based on individuals that did not share S-alleles. Twelve of the sixteen fitness variables were significantly reduced by inbreeding. For all the three life-history phases evaluated, self-fertilized offspring suffered a greater than 50% reduction in fitness, while full-sib and half-sib offspring suffered a less than 50% reduction in fitness. Theory indicates that fitness costs greater than 50% can result in an evolutionary trajectory toward a stable state of self-incompatibility (SI). This study suggests that dominance interactions at the S-locus provide a possible third stable state between SI and SC where biparental inbreeding increases mate availability with relatively minor fitness costs. This strategy allows weeds to establish in new environments while maintaining a functional SI system.

Constrained paths based on the Farey sequence in learning to juggle.

PubMed

Yamamoto, Kota; Tsutsui, Seijiro; Yamamoto, Yuji

2015-12-01

In this article we report the results of a study conducted to investigate the learning dynamics of three-ball juggling from the perspective of frequency locking. Based on the Farey sequence, we predicted that four stable coordination patterns, corresponding to dwell ratios of 0.83, 0.75, 0.67, and 0.50, would appear in the learning process. We examined the learning process in terms of task performance, taking into account individual differences in the amount of learning. We observed that the participants acquired individual-specific coordination patterns in a relatively early stage of learning, and that those coordination patterns were preserved in subsequent learning, even though performance in terms of number of successful consecutive throws increased substantially. This increase appeared to be related to a reduction in spatial variability of the juggling movements. Finally, the observed coordination patterns were in agreement with the predicted patterns, with the proviso that the pattern corresponding to a dwell ratio of 0.50 was not realized and only a hint of evidence was found for the dwell ratio of 0.67. This implies that the dwell ratios of 0.83 and 0.75 in particular exhibited a stable coordination structure due to strong frequency locking between the temporal variables of juggling. Copyright © 2015 Elsevier B.V. All rights reserved.

A theory for the evolution of other-regard integrating proximate and ultimate perspectives.

PubMed

Akçay, Erol; Van Cleve, Jeremy; Feldman, Marcus W; Roughgarden, Joan

2009-11-10

Although much previous work describes evolutionary mechanisms that promote or stabilize different social behaviors, we still have little understanding of the factors that drive animal behavior proximately. Here we present a modeling approach to answer this question. Our model rests on motivations to achieve objectives as the proximate determinants of behavior. We develop a two-tiered framework by first modeling the dynamics of a social interaction at the behavioral time scale and then find the evolutionarily stable objectives that result from the outcomes these dynamics produce. We use this framework to ask whether "other-regarding" motivations, which result from a kind of nonselfish objective, can evolve when individuals are engaged in a social interaction that entails a conflict between their material payoffs. We find that, at the evolutionarily stable state, individuals can be other-regarding in that they are motivated to increase their partners' payoff as well as their own. In contrast to previous theories, we find that such motivations can evolve because of their direct effect on fitness and do not require kin selection or a special group structure. We also derive general conditions for the evolutionary stability of other-regarding motivations. Our conditions indicate that other-regarding motivations are more likely to evolve when social interactions and behavioral objectives are both synergistic.

Positive expiratory pressure therapy versus other airway clearance techniques for bronchiectasis.

PubMed

Lee, Annemarie L; Burge, Angela T; Holland, Anne E

2017-09-27

People with bronchiectasis experience chronic cough and sputum production and require the prescription of airway clearance techniques (ACTs). A common type of ACT prescribed is positive expiratory pressure (PEP) therapy. A previous review has suggested that ACTs including PEP therapy are beneficial compared to no treatment in people with bronchiectasis. However, the efficacy of PEP therapy in a stable clinical state or during an acute exacerbation compared to other ACTs in bronchiectasis is unknown. The primary aim of this review was to determine the effects of PEP therapy compared with other ACTs on health-related quality of life (HRQOL), rate of acute exacerbations, and incidence of hospitalisation in individuals with stable or an acute exacerbation of bronchiectasis.Secondary aims included determining the effects of PEP therapy upon physiological outcomes and clinical signs and symptoms compared with other ACTs in individuals with stable or an acute exacerbation of bronchiectasis. We searched the Cochrane Airways Group Specialised Register of Trials, PEDro and clinical trials registries from inception to February 2017 and we handsearched relevant journals. Randomised controlled parallel and cross-over trials that compared PEP therapy versus other ACTs in participants with bronchiectasis. We used standard methodological procedures as outlined by Cochrane. Nine studies involving 213 participants met the inclusion criteria, of which seven were cross-over in design. All studies included adults with bronchiectasis, with eight including participants in a stable clinical state and one including participants experiencing an acute exacerbation. Eight studies used oscillatory PEP therapy, using either a Flutter or Acapella device and one study used Minimal PEP therapy. The comparison intervention differed between studies. The methodological quality of studies was poor, with cross-over studies including suboptimal or no washout period, and a lack of blinding of participants, therapists or personnel for outcome measure assessment in most studies. Clinical heterogeneity between studies limited meta-analysis.Daily use of oscillatory PEP therapy for four weeks was associated with improved general health according to the Short-Form 36 questionnaire compared to the active cycle of breathing technique (ACBT). When applied for three sessions over one week, minimal PEP therapy resulted in similar improvement in cough-related quality of life as autogenic drainage (AD) and L'expiration Lente Totale Glotte Ouverte en Decubitus Lateral (ELTGOL). Oscillatory PEP therapy twice daily for four weeks had similar effects on disease-specific HRQOL (MD -0.09, 95% CI -0.37 to 0.19; low-quality evidence). Data were not available to determine the incidence of hospitalisation or rate of exacerbation in clinically stable participants.Two studies of a single session comparison of oscillatory PEP therapy and gravity-assisted drainage (GAD) with ACBT had contrasting findings. One study found a similar sputum weight produced with both techniques (SMD 0.54g (-0.38 to 1.46; 20 participants); the other found greater sputum expectoration with GAD and ACBT (SMD 5.6 g (95% CI 2.91 to 8.29: 36 participants). There was no difference in sputum weight yielded between oscillatory PEP therapy and ACBT with GAD when applied daily for four weeks or during an acute exacerbation. Although a single session of oscillatory PEP therapy was associated with less sputum compared to AD (median difference 3.1 g (95% CI 1.5 to 4.8 g; one study, 31 participants), no difference between oscillatory PEP therapy and seated ACBT was evident. PEP therapy had a similar effect on dynamic and static measures of lung volumes and gas exchange as all other ACTs. A single session of oscillatory PEP therapy (Flutter) generated a similar level of fatigue as ACBT with GAD, but greater fatigue was noted with oscillatory PEP therapy compared to ACBT alone. The degree of breathlessness experienced with PEP therapy did not differ from other techniques. Among studies exploring adverse events, only one study reported nausea with use of oscillatory PEP therapy. PEP therapy appears to have similar effects on HRQOL, symptoms of breathlessness, sputum expectoration, and lung volumes compared to other ACTs when prescribed within a stable clinical state or during an acute exacerbation. The number of studies and the overall quality of the evidence were both low. In view of the chronic nature of bronchiectasis, additional information is needed to establish the long-term clinical effects of PEP therapy over other ACTs for outcomes that are important to people with bronchiectasis and on clinical parameters which impact on disease progression and patient morbidity in individuals with stable bronchiectasis. In addition, the role of PEP therapy during an acute exacerbation requires further exploration. This information is necessary to provide further guidance for prescription of PEP therapy for people with bronchiectasis.

Mixture modeling methods for the assessment of normal and abnormal personality, part II: longitudinal models.

PubMed

Wright, Aidan G C; Hallquist, Michael N

2014-01-01

Studying personality and its pathology as it changes, develops, or remains stable over time offers exciting insight into the nature of individual differences. Researchers interested in examining personal characteristics over time have a number of time-honored analytic approaches at their disposal. In recent years there have also been considerable advances in person-oriented analytic approaches, particularly longitudinal mixture models. In this methodological primer we focus on mixture modeling approaches to the study of normative and individual change in the form of growth mixture models and ipsative change in the form of latent transition analysis. We describe the conceptual underpinnings of each of these models, outline approaches for their implementation, and provide accessible examples for researchers studying personality and its assessment.

Intraindividual variability in cognitive performance in older adults: comparison of adults with mild dementia, adults with arthritis, and healthy adults.

PubMed

Hultsch, D F; MacDonald, S W; Hunter, M A; Levy-Bencheton, J; Strauss, E

2000-10-01

Intraindividual variability in latency and accuracy of cognitive performance across both trials and occasions was examined in 3 groups of older adults: healthy adults, adults with arthritis, and adults diagnosed with mild dementia. Participants completed 2 reaction-time and 2 episodic-memory tasks on 4 occasions. Results indicated that intraindividual variability in latency was greater in individuals diagnosed with mild dementia than in adults who were neurologically intact, regardless of their health status. Individual differences in variability were stable over time and across cognitive domains. Intraindividual variability was also related to level of performance and was uniquely predictive of neurological status, independent of level of performance. Results suggest that intraindividual variability may be a behavioral indicator of compromised neurological mechanisms.

Stability of chromosome aberrations in the blood lymphocytes of astronauts measured after space flight by FISH chromosome painting.

PubMed

George, K; Willingham, V; Cucinotta, F A

2005-10-01

Follow-up measurements of chromosome aberrations in the blood lymphocytes of astronauts were performed by FISH chromosome painting at various intervals from 5 months to more than 5 years after space flight and compared to preflight baseline measurements. For five of the six astronauts studied, the analysis of individual time courses for translocations revealed a temporal decline of yields with half-lives ranging from 10 to 58 months. The yield of exchanges remained unchanged for the sixth astronaut during an observation period of 5 months after flight. These results may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure.

Stability of chromosome aberrations in the blood lymphocytes of astronauts measured after space flight by FISH chromosome painting

NASA Technical Reports Server (NTRS)

George, K.; Willingham, V.; Cucinotta, F. A.

2005-01-01

Follow-up measurements of chromosome aberrations in the blood lymphocytes of astronauts were performed by FISH chromosome painting at various intervals from 5 months to more than 5 years after space flight and compared to preflight baseline measurements. For five of the six astronauts studied, the analysis of individual time courses for translocations revealed a temporal decline of yields with half-lives ranging from 10 to 58 months. The yield of exchanges remained unchanged for the sixth astronaut during an observation period of 5 months after flight. These results may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure.

Stress hormones predict hyperbolic time-discount rates six months later in adults.

PubMed

Takahashi, Taiki; Shinada, Mizuho; Inukai, Keigo; Tanida, Shigehito; Takahashi, Chisato; Mifune, Nobuhiro; Takagishi, Haruto; Horita, Yutaka; Hashimoto, Hirofumi; Yokota, Kunihiro; Kameda, Tatsuya; Yamagishi, Toshio

2010-01-01

Stress hormones have been associated with temporal discounting. Although time-discount rate is shown to be stable over a long term, no study to date examines whether individual differences in stress hormones could predict individuals' time-discount rates in the relatively distant future (e.g., six month later), which is of interest in neuroeconomics of stress-addiction association. We assessed 87 participants' salivary stress hormone (cortisol, cortisone, and alpha-amylase) levels and hyperbolic discounting of delayed rewards consisting of three magnitudes, at the time-interval of six months. For salivary steroid assays, we employed a liquid chromatography/ mass spectroscopy (LC/MS) method. The correlations between the stress hormone levels and time-discount rates were examined. We observed that salivary alpha-amylase (sAA) levels were negatively associated with time-discount rates in never-smokers. Notably, salivary levels of stress steroids (i.e., cortisol and cortisone) negatively and positively related to time-discount rates in men and women, respectively, in never-smokers. Ever-smokers' discount rates were not predicted from these stress hormone levels. Individual differences in stress hormone levels predict impulsivity in temporal discounting in the future. There are sex differences in the effect of stress steroids on temporal discounting; while there was no sex defference in the relationship between sAA and temporal discounting.

LABORATORY EVALUATION OF THE DEVELOPMENT OF Aedes aegypti IN TWO SEASONS: INFLUENCE OF DIFFERENT PLACES AND DIFFERENT DENSITIES

PubMed Central

Lopes, Tatiana Forte; Holcman, Marcia Moreira; Barbosa, Gerson Laurindo; Domingos, Maria de Fatima; Barreiros, Rosa Maria Oliveira Veiga

2014-01-01

Aedes aegypti is an important vector in Brazil being the main vector of the dengue-fever. This paper employs survival curves to describe the time in days from larvae to adult forms of Aedes aegypti raised, individually and collectively, and compares it during winter and spring when positioned inside and outside a laboratory. The study was conducted in São Vicente, a coastal city in Southeastern Brazil. The lowest water temperature in winter and in spring was 20 °C and the highest was 26 °C in spring. Higher and more stable temperatures were measured in the intra compared to the peri in both seasons. Consequently, larvae positioned in the intra resulted in the lowest median time to develop in the individual and collective experiment (nine and ten days, respectively). At least 25% of the larvae positioned in the intra in the individual experiment in the spring took only seven days to reach adulthood. Sex ratios and the median time development by sex did not show significant differences. These results indicate that efforts to control Aedes aegypti must be continuous and directed mainly to prevent the intra-domiciliary sites that can be infested in a week in order to reduce the human-vector contact. PMID:25229215

Individual differences in the development of early peer aggression: Integrating contributions of self-regulation, theory of mind, and parenting

PubMed Central

OLSON, SHERYL L.; LOPEZ-DURAN, NESTOR; LUNKENHEIMER, ERIKA S.; CHANG, HYEIN; SAMEROFF, ARNOLD J.

2014-01-01

This prospective longitudinal study focused on self-regulatory, social–cognitive, and parenting precursors of individual differences in children’s peer-directed aggression at early school age. Participants were 1993-year-old boys and girls who were reassessed following the transition to kindergarten (5.5–6 years). Peer aggression was assessed in preschool and school settings using naturalistic observations and teacher reports. Children’s self-regulation abilities and theory of mind understanding were assessed during a laboratory visit, and parenting risk (corporal punishment and low warmth/responsiveness) was assessed using interview-based and questionnaire measures. Individual differences in children’s peer aggression were moderately stable across the preschool to school transition. Preschool-age children who manifested high levels of aggressive peer interactions also showed lower levels of self-regulation and theory of mind understanding, and experienced higher levels of adverse parenting than others. Our main finding was that early corporal punishment was associated with increased levels of peer aggression across the transition from preschool to school, as was the interaction between low maternal emotional support and children’s early delays in theory of mind understanding. These data highlight the need for family-directed preventive efforts during the early preschool years. PMID:21262052

Using the SRQ–20 Factor Structure to Examine Changes in Mental Distress Following Typhoon Exposure

PubMed Central

Stratton, Kelcey J.; Richardson, Lisa K.; Tran, Trinh Luong; Tam, Nguyen Thanh; Aggen, Steven H.; Berenz, Erin C.; Trung, Lam Tu; Tuan, Tran; Buoi, La Thi; Ha, Tran Thu; Thach, Tran Duc; Amstadter, Ananda B.

2014-01-01

Empirical research is limited regarding postdisaster assessment of distress in developing nations. This study aimed to evaluate the factor structure of the 20-item Self-Reporting Questionnaire (SRQ–20) before and after an acute trauma, Typhoon Xangsane, in order to examine changes in mental health symptoms in an epidemiologic sample of Vietnamese adults. The study examined a model estimating individual item factor loadings, thresholds, and a latent change factor for the SRQ–20's single “general distress” common factor. The covariates of sex, age, and severity of typhoon exposure were used to evaluate the disaster-induced changes in SRQ–20 scores while accounting for possible differences in the relationship between individual measurement scale items and the latent mental health construct. Evidence for measurement noninvariance was found. However, allowing sex and age effects on the pre-typhoon and post-typhoon factors accounted for much of the noninvariance in the SRQ–20 measurement structure. A test of no latent change failed, indicating that the SRQ–20 detected significant individual differences in distress between pre- and post-typhoon assessment. Conditioning on age and sex, several typhoon exposure variables differentially predicted levels of distress change, including evacuation, personal injury, and peri-event fear. On average, females and older individuals reported higher levels of distress than males and younger individuals, respectively. The SRQ–20 is a valid and reasonably stable instrument that may be used in postdisaster contexts to assess emotional distress and individual changes in mental health symptoms. PMID:24512425

Measuring Individual Differences in Generic Beliefs in Conspiracy Theories Across Cultures: Conspiracy Mentality Questionnaire

PubMed Central

Bruder, Martin; Haffke, Peter; Neave, Nick; Nouripanah, Nina; Imhoff, Roland

2013-01-01

Conspiracy theories are ubiquitous when it comes to explaining political events and societal phenomena. Individuals differ not only in the degree to which they believe in specific conspiracy theories, but also in their general susceptibility to explanations based on such theories, that is, their conspiracy mentality. We present the Conspiracy Mentality Questionnaire (CMQ), an instrument designed to efficiently assess differences in the generic tendency to engage in conspiracist ideation within and across cultures. The CMQ is available in English, German, and Turkish. In four studies, we examined the CMQ’s factorial structure, reliability, measurement equivalence across cultures, and its convergent, discriminant, and predictive validity. Analyses based on a cross-cultural sample (Study 1a; N = 7,766) supported the conceptualization of conspiracy mentality as a one-dimensional construct across the three language versions of the CMQ that is stable across time (Study 1b; N = 141). Multi-group confirmatory factor analysis demonstrated cross-cultural measurement equivalence of the CMQ items. The instrument could therefore be used to examine differences in conspiracy mentality between European, North American, and Middle Eastern cultures. In Studies 2–4 (total N = 476), we report (re-)analyses of three datasets demonstrating the validity of the CMQ in student and working population samples in the UK and Germany. First, attesting to its convergent validity, the CMQ was highly correlated with another measure of generic conspiracy belief. Second, the CMQ showed patterns of meaningful associations with personality measures (e.g., Big Five dimensions, schizotypy), other generalized political attitudes (e.g., social dominance orientation and right-wing authoritarianism), and further individual differences (e.g., paranormal belief, lack of socio-political control). Finally, the CMQ predicted beliefs in specific conspiracy theories over and above other individual difference measures. PMID:23641227

Individuals in food webs: the relationships between trophic position, omnivory and among-individual diet variation.

PubMed

Svanbäck, Richard; Quevedo, Mario; Olsson, Jens; Eklöv, Peter

2015-05-01

Among-individual diet variation is common in natural populations and may occur at any trophic level within a food web. Yet, little is known about its variation among trophic levels and how such variation could affect phenotypic divergence within populations. In this study we investigate the relationships between trophic position (the population's range and average) and among-individual diet variation. We test for diet variation among individuals and across size classes of Eurasian perch (Perca fluviatilis), a widespread predatory freshwater fish that undergoes ontogenetic niche shifts. Second, we investigate among-individual diet variation within fish and invertebrate populations in two different lake communities using stable isotopes. Third, we test potential evolutionary implications of population trophic position by assessing the relationship between the proportion of piscivorous perch (populations of higher trophic position) and the degree of phenotypic divergence between littoral and pelagic perch sub-populations. We show that among-individual diet variation is highest at intermediate trophic positions, and that this high degree of among-individual variation likely causes an increase in the range of trophic positions among individuals. We also found that phenotypic divergence was negatively related to trophic position in a population. This study thus shows that trophic position is related to and may be important for among-individual diet variation as well as to phenotypic divergence within populations.

Transfer of learning relates to intrinsic connectivity between hippocampus, ventromedial prefrontal cortex, and large-scale networks.

PubMed

Gerraty, Raphael T; Davidow, Juliet Y; Wimmer, G Elliott; Kahn, Itamar; Shohamy, Daphna

2014-08-20

An important aspect of adaptive learning is the ability to flexibly use past experiences to guide new decisions. When facing a new decision, some people automatically leverage previously learned associations, while others do not. This variability in transfer of learning across individuals has been demonstrated repeatedly and has important implications for understanding adaptive behavior, yet the source of these individual differences remains poorly understood. In particular, it is unknown why such variability in transfer emerges even among homogeneous groups of young healthy participants who do not vary on other learning-related measures. Here we hypothesized that individual differences in the transfer of learning could be related to relatively stable differences in intrinsic brain connectivity, which could constrain how individuals learn. To test this, we obtained a behavioral measure of memory-based transfer outside of the scanner and on a separate day acquired resting-state functional MRI images in 42 participants. We then analyzed connectivity across independent component analysis-derived brain networks during rest, and tested whether intrinsic connectivity in learning-related networks was associated with transfer. We found that individual differences in transfer were related to intrinsic connectivity between the hippocampus and the ventromedial prefrontal cortex, and between these regions and large-scale functional brain networks. Together, the findings demonstrate a novel role for intrinsic brain dynamics in flexible learning-guided behavior, both within a set of functionally specific regions known to be important for learning, as well as between these regions and the default and frontoparietal networks, which are thought to serve more general cognitive functions. Copyright © 2014 the authors 0270-6474/14/3411297-07$15.00/0.

Reverters from PD-MCI to cognitively intact are at risk for future cognitive impairment: Analysis of the PPMI cohort.

PubMed

Jones, Jacob D; Kuhn, Taylor P; Szymkowicz, Sarah M

2018-02-01

Past studies have shown that a large portion of individuals with Parkinson's disease (PD) and mild cognitive impairment (MCI) will revert to a cognitively intact (CI) status in the future. Aging studies have shown that individuals who revert from MCI to CI are at increased risk for reconverting to MCI or dementia in the future. The current study examined if individuals who revert from PD-mild cognitive impairment (PD-MCI) to CI will be at increased risk for future PD-MCI and Parkinson's disease dementia (PDD). The study utilized data from the Parkinson's Progression Markers Initiative (PPMI). The sample included 364 newly diagnosed PD participants who were followed annually for up to 4 years. Based on the first and second assessments, we identified individuals who were CI at each assessment (CI-Stable) and individuals who were PD-MCI at baseline but then reverted to CI (Reversion). Analyses examined if participants in the Reversion group were at greater risk, relative to the CI-Stable group, for cognitive impairment at future assessments. Participants in the Reversion group were at greater risk for future cognitive impairment (PD-MCI or PDD) at the 2nd, 3rd and 4th annual follow-up, relative to the CI-Stable group. The Reversion group continued to be at increased risk for future cognitive impairment when adjusting for age, gender, education, depressive symptoms, and motor severity. A large proportion of individuals with PD-MCI will not show evidence of cognitive impairment within a year. However, these "reverters" continue to be at risk for future development of cognitive impairment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Uncovering patterns of spring migration in the monarch butterfly using stable isotopes and demographic models

NASA Astrophysics Data System (ADS)

Norris, R.; Miller, N.; Wassenaar, L.; Hobson, K.

2010-12-01

Each spring, millions of monarch butterflies (Danaus plexippus) migrate up to 3000 km from central Mexico to re-colonize eastern North America. However, despite centuries of research, the patterns of re-colonization are not well understood. We combined stable-hydrogen (δD) and -carbon (δ13C) isotope measurements with demographic models to test (1) whether individuals sampled in the northern part of the breeding range in the Great Lakes originate directly from Mexico or are second generation individuals born in the southern US and (2) to estimate whether populations on the eastern seaboard migrate longitudinally over the Appalachians or originate directly from the Gulf Coast. In the Great Lakes, we found that the majority of individuals were second-generation monarchs born in the Gulf Coast and Central regions of the US. However, 25% individuals originated directly from Mexico and we estimated that these individuals produced the majority of offspring born in the Great Lakes region during June. On the eastern seaboard, we found the majority of monarchs (88%) originated in the mid-west and Great Lakes regions, providing the first direct evidence that second generation monarchs born in June complete a (trans-) longitudinal migration across the Appalachian mountains. The remaining individuals (12%) originated from parents that migrated directly from the Gulf coast during early spring. Our results demonstrate how stable isotopes, when combined with ecological data, can provide insights into patterns of connectivity in migratory insects that have been impossible to test using conventional techniques. The migration patterns presented here have important implications for predicting future changes in population size and for developing effective conservation plans for this species.

Feeding range of age 1+ year Eurasian perch Perca fluviatilis in the Baltic Sea.

PubMed

Ahlbeck Bergendahl, I; Holliland, P B; Hansson, S; Karlöf, O

2017-05-01

Using the widespread Eurasian perch Perca fluviatilis as a model organism, feeding ranges were investigated using stable-isotope ratios (δ 15 N and δ 13 C) and body condition. Differences were found between closely located sampling sites in a littoral area without obvious migration barriers, indicating that individual fish had small feeding ranges. Body condition differences between sampled stations were consistent over 4 years. Such sedentary behaviour is important to consider in, e.g. fisheries management and environmental monitoring, as local catch regulations may be meaningful or geographic stability in sampling locations may reduce noise in data. © 2017 The Fisheries Society of the British Isles.

Why does working memory capacity predict variation in reading comprehension? On the influence of mind wandering and executive attention.

PubMed

McVay, Jennifer C; Kane, Michael J

2012-05-01

Some people are better readers than others, and this variation in comprehension ability is predicted by measures of working memory capacity (WMC). The primary goal of this study was to investigate the mediating role of mind-wandering experiences in the association between WMC and normal individual differences in reading comprehension, as predicted by the executive-attention theory of WMC (e.g., Engle & Kane, 2004). We used a latent-variable, structural-equation-model approach, testing skilled adult readers on 3 WMC span tasks, 7 varied reading-comprehension tasks, and 3 attention-control tasks. Mind wandering was assessed using experimenter-scheduled thought probes during 4 different tasks (2 reading, 2 attention-control). The results support the executive-attention theory of WMC. Mind wandering across the 4 tasks loaded onto a single latent factor, reflecting a stable individual difference. Most important, mind wandering was a significant mediator in the relationship between WMC and reading comprehension, suggesting that the WMC-comprehension correlation is driven, in part, by attention control over intruding thoughts. We discuss implications for theories of WMC, attention control, and reading comprehension.

Unfolding dimension and the search for functional markers in the human electroencephalogram

NASA Astrophysics Data System (ADS)

Dünki, Rudolf M.; Schmid, Gary Bruno

1998-02-01

A biparametric approach to dimensional analysis in terms of a so-called ``unfolding dimension'' is introduced to explore the extent to which the human EEG can be described by stable features characteristic of an individual despite the well-known problems of intraindividual variability. Our analysis comprises an EEG data set recorded from healthy individuals over a time span of 5 years. The outcome is shown to be comparable to advanced linear methods of spectral analysis with regard to intraindividual specificity and stability over time. Such linear methods have not yet proven to be specific to the EEG of different brain states. Thus we have also investigated the specificity of our biparametric approach by comparing the mental states schizophrenic psychosis and remission, i.e., illness versus full recovery. A difference between EEG in psychosis and remission became apparent within recordings taken at rest with eyes closed and no stimulated or requested mental activity. Hence our approach distinguishes these functional brain states even in the absence of an active or intentional stimulus. This sheds a different light upon theories of schizophrenia as an information-processing disturbance of the brain.

A bright side, facet analysis of histrionic personality disorder: the relationship between the HDS Colourful factor and the NEO-PI-R facets in a large adult sample.

PubMed

Furnham, Adrian

2014-01-01

This study looks at "bright-side," Big Five Personality trait correlates of a "dark-side" Personality Disorder, namely Histrionic Personality Disorder (HPD). More than 5000 British adults completed the Neuroticism Extraversion Openness Personality Inventory-Revised (Costa & McCrae, 1985), which measures the Big Five Personality factors at the Domain (Super Factor) and the Facet (Factor) level, as well as the Hogan Development Survey (HDS; Hogan & Hogan, 2009), which has a measure of HPD, exclusively called "Colourful" in the HDS terminology. Correlation and regression results confirmed many of the associations between these "bright" and "dark" side individual difference variables. The Colourful (HPD) score from the HDS was the criterion variable in all analyses. Colourful individuals are high on Extraversion and Openness, but also Stable and disagreeable. The Facet analysis identified Assertiveness and Immodesty as particularly characteristic of that type. The study confirmed work on HPD using different population groups and different measures, showing that personality traits are predictable and correlated with various personality disorders.

Trajectories of premorbid childhood and adolescent functioning in schizophrenia-spectrum psychoses: A first-episode study.

PubMed

Horton, Leslie E; Tarbox, Sarah I; Olino, Thomas M; Haas, Gretchen L

2015-06-30

Evidence of social and behavioral problems preceding the onset of schizophrenia-spectrum psychoses is consistent with a neurodevelopmental model of these disorders. Here we predict that individuals with a first episode of schizophrenia-spectrum psychoses will evidence one of three patterns of premorbid adjustment: an early deficit, a deteriorating pattern, or adequate or good social adjustment. Participants were 164 (38% female; 31% black) individuals ages 15-50 with a first episode of schizophrenia-spectrum psychoses. Premorbid adjustment was assessed using the Cannon-Spoor Premorbid Adjustment Scale. We compared the fit of a series of growth mixture models to examine premorbid adjustment trajectories, and found the following 3-class model provided the best fit with: a "stable-poor" adjustment class (54%), a "stable-good" adjustment class (39%), and a "deteriorating" adjustment class (7%). Relative to the "stable-good" class, the "stable-poor" class experienced worse negative symptoms at 1-year follow-up, particularly in the social amotivation domain. This represents the first known growth mixture modeling study to examine premorbid functioning patterns in first-episode schizophrenia-spectrum psychoses. Given that the stable-poor adjustment pattern was most prevalent, detection of social and academic maladjustment as early as childhood may help identify people at increased risk for schizophrenia-spectrum psychoses, potentially increasing feasibility of early interventions. Published by Elsevier Ireland Ltd.

Sources of individual differences in depressive symptoms: analysis of two samples of twins and their families.

PubMed

Kendler, K S; Walters, E E; Truett, K R; Heath, A C; Neale, M C; Martin, N G; Eaves, L J

1994-11-01

Self-reported symptoms of depression are commonly used in mental health research to assess current psychiatric state, yet wide variation in these symptoms among individuals has been found in both clinical and epidemiologic populations. The authors sought to understand, from a genetic-epidemiologic perspective, the sources of individual differences in depressive symptoms. Self-reported symptoms of depression were assessed in two samples of twins and their spouses, parents, siblings, and offspring: one sample contained volunteer twins recruited through the American Association of Retired Persons and their relatives (N = 19,203 individuals) and the other contained twins from a population-based twin registry in Virginia and their relatives (N = 11,242 individuals). Model fitting by an iterative, diagonal, weighted least squares method was applied to the 80 different family relationships in the extended twin-family design. Independent analyses of the two samples revealed that the level of depressive symptoms was modestly familial, and familial resemblance could be explained solely by genetic factors and spousal resemblance. The estimated heritability of depressive symptoms was between 30% and 37%. There was no evidence that the liability to depressive symptoms was environmentally transmitted from parents to offspring or was influenced by environmental factors shared either generally among siblings or specifically between twins. With correction for unreliability of measurement, genetic factors accounted for half of the stable variance in depressive symptoms. Depressive symptoms in adulthood partly reflect enduring characteristics of temperament that are substantially influenced by hereditary factors but little, or not at all, by shared environmental experiences in the family of origin.

Patterns of Kidney Function Decline in Autosomal Dominant Polycystic Kidney Disease: A Post Hoc Analysis From the HALT-PKD Trials.

PubMed

Brosnahan, Godela M; Abebe, Kaleab Z; Moore, Charity G; Rahbari-Oskoui, Frederic F; Bae, Kyongtae T; Grantham, Jared J; Schrier, Robert W; Braun, William E; Chapman, Arlene B; Flessner, Michael F; Harris, Peter C; Hogan, Marie C; Perrone, Ronald D; Miskulin, Dana C; Steinman, Theodore I; Torres, Vicente E

2018-05-01

Previous clinical studies of autosomal dominant polycystic kidney disease (ADPKD) reported that loss of kidney function usually follows a steep and relentless course. A detailed examination of individual patterns of decline in estimated glomerular filtration rate (eGFR) has not been performed. Longitudinal post hoc analysis of data collected during the Halt Progression of Polycystic Kidney Disease (HALT-PKD) trials. 494 HALT-PKD Study A participants (younger; preserved eGFR) and 435 Study B participants (older; reduced eGFR) who had more than 3 years of follow-up and 7 or more eGFR assessments. Longitudinal eGFR assessments using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation. Demographic, clinical, laboratory, and imaging features of participants. Probability of linear and nonlinear decline patterns or of stable eGFR calculated for each participant from a Bayesian model of individual eGFR trajectories. Most (62.5% in Study A and 81% in Study B) participants had a linear decline in eGFR during up to 8 years of follow-up. A proportion (22% in Study A and 13% in Study B) of progressors had a nonlinear pattern. 15.5% of participants in Study A and 6% in Study B had a prolonged (≥4.5 years) period of stable eGFRs. These individuals (Study A) had significantly smaller total kidney volumes, higher renal blood flows, lower urinary albumin excretion, and lower body mass index at baseline and study end. In Study B, participants with reduced but stable eGFRs were older than the progressors. Two-thirds of nonprogressors in both studies had PKD1 mutations, with enrichment for weak nontruncating mutations. Relatively short follow-up of a clinical trial population. Although many individuals with ADPKD have a linear decline in eGFR, prolonged intervals of stable GFRs occur in a substantial fraction. Lower body mass index was associated with more stable kidney function in early ADPKD. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Bechstein's bats maintain individual social links despite a complete reorganisation of their colony structure

NASA Astrophysics Data System (ADS)

Baigger, A.; Perony, N.; Reuter, M.; Leinert, V.; Melber, M.; Grünberger, S.; Fleischmann, D.; Kerth, G.

2013-09-01

Several social mammals, including elephants and some primates, whales and bats, live in multilevel societies that form temporary subgroups. Despite these fission-fusion dynamics, group members often maintain long-term bonds. However, it is unclear whether such individual links and the resulting stable social subunits continue to exist after a complete reorganisation of a society, e.g. following a population crash. Here, we employed a weighted network analysis on 7,109 individual roosting records collected over 4 years in a wild Bechstein's bat colony. We show that, in response to a strong population decline, the colony's two stable social subunits fused into a non-modular social network. Nevertheless, in the first year after the crash, long-term bonds were still detectable, suggesting that the bats remembered previous individual relationships. Our findings are important for understanding the flexibility of animal societies in the face of dramatic changes and for the conservation of social mammals with declining populations.

Bechstein's bats maintain individual social links despite a complete reorganisation of their colony structure.

PubMed

Baigger, A; Perony, N; Reuter, M; Leinert, V; Melber, M; Grünberger, S; Fleischmann, D; Kerth, G

2013-09-01

Several social mammals, including elephants and some primates, whales and bats, live in multilevel societies that form temporary subgroups. Despite these fission-fusion dynamics, group members often maintain long-term bonds. However, it is unclear whether such individual links and the resulting stable social subunits continue to exist after a complete reorganisation of a society, e.g. following a population crash. Here, we employed a weighted network analysis on 7,109 individual roosting records collected over 4 years in a wild Bechstein's bat colony. We show that, in response to a strong population decline, the colony's two stable social subunits fused into a non-modular social network. Nevertheless, in the first year after the crash, long-term bonds were still detectable, suggesting that the bats remembered previous individual relationships. Our findings are important for understanding the flexibility of animal societies in the face of dramatic changes and for the conservation of social mammals with declining populations.

Emotion-related self-regulation and its relation to children's maladjustment.

PubMed

Eisenberg, Nancy; Spinrad, Tracy L; Eggum, Natalie D

2010-01-01

The development of children's emotion-related self-regulation appears to be related to, and likely involved in, many aspects of children's development. In this review, the distinction between effortful self-regulatory processes and those that are somewhat less voluntary is discussed, and literature on the former capacities is reviewed. Emotion-related self-regulation develops rapidly in the early years of life and improves more slowly into adulthood. Individual differences in children's self-regulation are fairly stable after the first year or two of life. Such individual differences are inversely related to at least some types of externalizing problems. Findings for internalizing problems are less consistent and robust, although emotion-related self-regulation appears to be inversely related to internalizing problems after the early years. Self-regulatory capacities have been related to both genetic and environmental factors and their interaction. Some interventions designed to foster self-regulation and, hence, reduce maladjustment, have proved to be at least partially effective.

Emotion-Related Self-Regulation and Its Relation to Children’s Maladjustment

PubMed Central

Eisenberg, Nancy; Spinrad, Tracy L.; Eggum, Natalie D.

2010-01-01

The development of children’s emotion-related self-regulation appears to be related to, and likely involved in, many aspects of children’s development. In this review, the distinction between effortful self-regulatory processes and those that are somewhat less voluntary is discussed, and literature on the former capacities is reviewed. Emotion-related self-regulation develops rapidly in the early years of life and improves more slowly into adulthood. Individual differences in children’s self-regulation are fairly stable after the first year or two of life. Such individual differences are inversely related to at least some types of externalizing problems. Findings for internalizing problems are less consistent and robust, although emotion-related self-regulation appears to be inversely related to internalizing problems after the early years. Self-regulatory capacities have been related to both genetic and environmental factors and their interaction. Some interventions designed to foster self-regulation and, hence, reduce maladjustment, have proved to be at least partially effective. PMID:20192797

Angels and demons are among us: assessing individual differences in belief in pure evil and belief in pure good.

PubMed

Webster, Russell J; Saucier, Donald A

2013-11-01

We conducted five studies to demonstrate that individuals' beliefs in pure evil (BPE) and in pure good (BPG) are valid and important psychological constructs. First, these studies together demonstrated that BPE and BPG are reliable, unitary, and stable constructs each composed of eight theoretically interdependent dimensions. Second, these studies showed that across a wide variety of different measures, higher BPE consistently related to greater intergroup aggression (e.g., supporting the death penalty and preemptive military aggression) and less intergroup prosociality (e.g., opposing criminal rehabilitation, proracial policies, and beneficial social programs), while higher BPG consistently related to less intergroup aggression (e.g., opposing proviolent foreign relations and torture) and greater intergroup prosociality (e.g., supporting criminal rehabilitation and support for diplomacy). In sum, these studies evidence that BPE and BPG relate to aggressive and prosocial orientations toward others and have strong potential to advance current theories on prejudice, aggression, and prosociality.

Unraveling the nature of autism: finding order amid change

PubMed Central

Hellendoorn, Annika; Wijnroks, Lex; Leseman, Paul P. M.

2015-01-01

In this article, we hypothesize that individuals with autism spectrum disorder (ASD) are born with a deficit in invariance detection, which is a learning process whereby people and animals come to attend the relatively stable patterns or structural regularities in the changing stimulus array. This paper synthesizes a substantial body of research which suggests that a deficit in the domain-general perceptual learning process of invariant detection in ASD can lead to a cascade of consequences in different developmental domains. We will outline how this deficit in invariant detection can cause uncertainty, unpredictability, and a lack of control for individuals with ASD and how varying degrees of impairments in this learning process can account for the heterogeneity of the ASD phenotype. We also describe how differences in neural plasticity in ASD underlie the impairments in perceptual learning. The present account offers an alternative to prior theories and contributes to the challenge of understanding the developmental trajectories that result in the variety of autistic behaviors. PMID:25870581

Efficiency of Leptotrombidium chiggers (Acari: Trombiculidae) at transmitting Orientia tsutsugamushi to laboratory mice.

PubMed

Lerdthusnee, Kriangkrai; Khlaimanee, Nittaya; Monkanna, Taweesak; Sangjun, Noppadon; Mungviriya, Siriporn; Linthicum, Kenneth J; Frances, Stephen P; Kollars, Thomas M; Coleman, Russell E

2002-05-01

Thirteen different laboratory colonies of Leptotrombidim chiggers [L. chiangraiensis Tanskul & Linthicum, L. deliense Walch and L. imphalum (Vercammen-Grandjean &Langston)] were evaluated for their ability to transmit Orientia tsutsugamushi (Hyashi) to mice. Of 4,372 transmission attempts using individual chiggers from all 13 colonies, 75% (n = 3,275) successfully infected mice. Transmission rates for the individual chigger colonies ranged from 7 to 80%. Increasing the number of chiggers that fed on a given mouse generally increased transmission rates. Transmission of O. tsutsugamushi to mice by different generations (F1-F11) of certain chigger colonies was stable; however, transmission rates varied greatly in other colonies. Transmission rates (both vertical and horizontal) of several L. changraiensis colonies and the L. deliense colony were the highest, suggesting that these colonies may be useful for the development of a chigger-challenge model that can be used to evaluate the efficacy of candidate scrub typhus vaccines or therapeutic agents in laboratory mice.

Stability of upper face sexual dimorphism in central European populations (Czech Republic) during the modern age.

PubMed

Bejdová, Šárka; Dupej, Ján; Krajíček, Václav; Velemínská, Jana; Velemínský, Petr

2018-01-01

One of the most fundamental issues in forensic anthropology is the determination of sex and population affinity based on various skeletal elements. Therefore, we compared the sexual dimorphism of the upper facial skeleton from a recent Czech population (twenty-first century) with that of a population from Early Modern Age Bohemia (sixteenth to eighteenth centuries). Methods of geometric morphometrics were applied. According to the results, sexual dimorphism in terms of size, shape, and form was statistically significant in both populations. The best results of sex estimation originated from analyses of form. Thus, both size and shape differences should be taken into account for determination of the sex. The accuracy of prediction achieved 91.1% for individuals in the recent population and 87.5% for individuals from the early modern population. Only minor differences were found between sexual dimorphism in the studied populations. We conclude that sexual dimorphism of the upper facial skeleton is stable during the relatively short time period.

Multivariable Sensors for Ubiquitous Monitoring of Gases in the Era of Internet of Things and Industrial Internet.

PubMed

Potyrailo, Radislav A

2016-10-12

Modern gas monitoring scenarios for medical diagnostics, environmental surveillance, industrial safety, and other applications demand new sensing capabilities. This Review provides analysis of development of new generation of gas sensors based on the multivariable response principles. Design criteria of these individual sensors involve a sensing material with multiresponse mechanisms to different gases and a multivariable transducer with independent outputs to recognize these different gas responses. These new sensors quantify individual components in mixtures, reject interferences, and offer more stable response over sensor arrays. Such performance is attractive when selectivity advantages of classic gas chromatography, ion mobility, and mass spectrometry instruments are canceled by requirements for no consumables, low power, low cost, and unobtrusive form factors for Internet of Things, Industrial Internet, and other applications. This Review is concluded with a perspective for future needs in fundamental and applied aspects of gas sensing and with the 2025 roadmap for ubiquitous gas monitoring.

Multiple Near Wake Patterns Behind Annular Rings

NASA Astrophysics Data System (ADS)

Zhang, Jinzhong; Higuchi, Hiroshi; Muzas, Brian K.; Furuya, Shojiro

1996-11-01

Wake interactions behind concentric annular rings at different spacing ratios were experimentally investigated. The flow visualization, laser Doppler velocimetry data and results from the particle tracking velocimetry are presented and discussed. Jets through individual slots merged in multiply-stable, axisymmetric manners. Most flow patterns were persistent unless the flow was strongly disturbed. The vortex interactions from individual annular elements were also axisymmetric in the near wake. This is in contrast to the asymmetric flows observed earlier behind two-dimensional slotted plates (Higuchi et al. J. Aircraft 26 1989, Phys. Fluids 6(1), 1994). The intermediate wake, however, was dominated by large scale, three-dimensional wake motions even at moderate porosity. Onset of the specific flow patterns was associated with the interactions among start-up vortices. Given model geometry, different turbulent structures and mean velocity profiles were observed in the intermediate wake depending on the near wake pattern. *BKM was a NSF-REU Program undergrad. from Princeton U. and SF was from Mitsubishi Heavy Industries. This work was suppoted in part by the Naval Air Warfare Center.

Improving the Signal for U.S. Navy Officer Productivity

DTIC Science & Technology

2014-12-01

American Economic Review, 93(1), 216–240. Retrieved from http://www.jstor.org/stable/3132169 Mankiw , G., Romer, D., & Weil, D. (1992). A contribution...individual perfonnance appraisal system to optimally signal officer productivity. This paper utilizes the economics literature on individual perfonnance...signal officer productivity. This paper utilizes the economics literature on individual performance appraisals and promotion systems as the lens

Long-term and within-day variability of working memory performance and EEG in individuals.

PubMed

Gevins, Alan; McEvoy, Linda K; Smith, Michael E; Chan, Cynthia S; Sam-Vargas, Lita; Baum, Cliff; Ilan, Aaron B

2012-07-01

Assess individual-subject long-term and within-day variability of a combined behavioral and EEG test of working memory. EEGs were recorded from 16 adults performing n-back working memory tasks, with 10 tested in morning and afternoon sessions over several years. Participants were also tested after ingesting non-prescription medications or recreational substances. Performance and EEG measures were analyzed to derive an Overall score and three constituent sub-scores characterizing changes in performance, cortical activation, and alertness from each individual's baseline. Long-term and within-day variability were determined for each score; medication effects were assessed by reference to each individual's normal day-to-day variability. Over the several year period, the mean Overall score and sub-scores were approximately zero with standard deviations less than one. Overall scores were lower and their variability higher in afternoon relative to morning sessions. At the group level, alcohol, diphenhydramine and marijuana produced significant effects, but there were large individual differences. Objective working memory measures incorporating performance and EEG are stable over time and sensitive at the level of individual subjects to interventions that affect neurocognitive function. With further research these measures may be suitable for use in individualized medical care by providing a sensitive assessment of incipient illness and response to treatment. Published by Elsevier Ireland Ltd.

Daytime bright light exposure, metabolism, and individual differences in wake and sleep energy expenditure during circadian entrainment and misalignment

PubMed Central

Melanson, Edward L.; Ritchie, Hannah K.; Dear, Tristan B.; Catenacci, Victoria; Shea, Karen; Connick, Elizabeth; Moehlman, Thomas M.; Stothard, Ellen R.; Higgins, Janine; McHill, Andrew W.; Wright, Kenneth P.

2018-01-01

Daytime light exposure has been reported to impact or have no influence on energy metabolism in humans. Further, whether inter-individual differences in wake, sleep, 24 h energy expenditure, and RQ during circadian entrainment and circadian misalignment are stable across repeated 24 h assessments is largely unknown. We present data from two studies: Study 1 of 15 participants (7 females) exposed to three light exposure conditions: continuous typical room ~100 lx warm white light, continuous ~750 lx warm white light, and alternating hourly ~750 lx warm white and blue-enriched white light on three separate days in a randomized order; and Study 2 of 14 participants (8 females) during circadian misalignment induced by a simulated night shift protocol. Participants were healthy, free of medical disorders, medications, and illicit drugs. Participants maintained a consistent 8 h per night sleep schedule for one week as an outpatient prior to the study verified by wrist actigraphy, sleep diaries, and call-ins to a time stamped recorder. Participants consumed an outpatient energy balance research diet for three days prior to the study. The inpatient protocol for both studies consisted of an initial sleep disorder screening night. For study 1, this was followed by three standard days with 16 h scheduled wakefulness and 8 h scheduled nighttime sleep. For Study 2, it was followed by 16 h scheduled wake and 8 h scheduled sleep at habitual bedtime followed by three night shifts with 8 h scheduled daytime sleep. Energy expenditure was measured using whole-room indirect calorimetry. Constant posture bedrest conditions were maintained to control for energy expenditure associated with activity and the baseline energy balance diet was continued with the same exact meals across days to control for thermic effects of food. No significant impact of light exposure was observed on metabolic outcomes in response to daytime light exposure. Inter-individual variability in energy expenditure was systematic and ranged from substantial to almost perfect consistency during both nighttime sleep and circadian misalignment. Findings show robust and stable trait-like individual differences in whole body 24 h, waking, and sleep energy expenditure, 24 h respiratory quotient—an index of a fat and carbohydrate oxidation—during repeated assessments under entrained conditions, and also in 24 h and sleep energy expenditure during repeated days of circadian misalignment. PMID:29876528

Daytime bright light exposure, metabolism, and individual differences in wake and sleep energy expenditure during circadian entrainment and misalignment.

PubMed

Melanson, Edward L; Ritchie, Hannah K; Dear, Tristan B; Catenacci, Victoria; Shea, Karen; Connick, Elizabeth; Moehlman, Thomas M; Stothard, Ellen R; Higgins, Janine; McHill, Andrew W; Wright, Kenneth P

2018-01-01

Daytime light exposure has been reported to impact or have no influence on energy metabolism in humans. Further, whether inter-individual differences in wake, sleep, 24 h energy expenditure, and RQ during circadian entrainment and circadian misalignment are stable across repeated 24 h assessments is largely unknown. We present data from two studies: Study 1 of 15 participants (7 females) exposed to three light exposure conditions: continuous typical room ~100 lx warm white light, continuous ~750 lx warm white light, and alternating hourly ~750 lx warm white and blue-enriched white light on three separate days in a randomized order; and Study 2 of 14 participants (8 females) during circadian misalignment induced by a simulated night shift protocol. Participants were healthy, free of medical disorders, medications, and illicit drugs. Participants maintained a consistent 8 h per night sleep schedule for one week as an outpatient prior to the study verified by wrist actigraphy, sleep diaries, and call-ins to a time stamped recorder. Participants consumed an outpatient energy balance research diet for three days prior to the study. The inpatient protocol for both studies consisted of an initial sleep disorder screening night. For study 1, this was followed by three standard days with 16 h scheduled wakefulness and 8 h scheduled nighttime sleep. For Study 2, it was followed by 16 h scheduled wake and 8 h scheduled sleep at habitual bedtime followed by three night shifts with 8 h scheduled daytime sleep. Energy expenditure was measured using whole-room indirect calorimetry. Constant posture bedrest conditions were maintained to control for energy expenditure associated with activity and the baseline energy balance diet was continued with the same exact meals across days to control for thermic effects of food. No significant impact of light exposure was observed on metabolic outcomes in response to daytime light exposure. Inter-individual variability in energy expenditure was systematic and ranged from substantial to almost perfect consistency during both nighttime sleep and circadian misalignment. Findings show robust and stable trait-like individual differences in whole body 24 h, waking, and sleep energy expenditure, 24 h respiratory quotient-an index of a fat and carbohydrate oxidation-during repeated assessments under entrained conditions, and also in 24 h and sleep energy expenditure during repeated days of circadian misalignment.

Identification of suitable reference genes for quantitative gene expression analysis in rat adipose stromal cells induced to trilineage differentiation.

PubMed

Santos, Bruno Paiva Dos; da Costa Diesel, Luciana Fraga; da Silva Meirelles, Lindolfo; Nardi, Nance Beyer; Camassola, Melissa

2016-12-15

This study was designed to (i) identify stable reference genes for the analysis of gene expression during in vitro differentiation of rat adipose stromal cells (rASCs), (ii) recommend stable genes for individual treatment conditions, and (iii) validate these genes by comparison with normalization results from stable and unstable reference genes. On the basis of a literature review, eight genes were selected: Actb, B2m, Hprt1, Ppia, Rplp0, Rpl13a, Rpl5, and Ywhaz. Genes were ranked according to their stability under different culture conditions as assessed using GenNorm, NormFinder, and RefFinder algorithms. Although the employed algorithms returned different rankings, the most frequently top-ranked genes were: B2m and/or Ppia for all 28day treatments (ALL28); Ppia and Hprt1 (adipogenic differentiation; A28), B2m (chondrogenic differentiation; C28), Rpl5 (controls maintained in complete culture medium; CCM), Rplp0 (osteogenic differentiation for 3days; O3), Rpl13a and Actb (osteogenic differentiation for 7days; O7), Rplp0 and Ppia (osteogenic differentiation for 14days; O14), Hprt1 and Ppia (osteogenic differentiation for 28days; O28), as well as Actb (all osteogenesis time points combined; ALLOSTEO). The obtained results indicate that the performance of reference genes depends on the differentiation protocol and on the analysis time, thus providing valuable information for the design of RT-PCR experiments. Copyright © 2016. Published by Elsevier B.V.

Does natural weathering change the stable isotope composition (²H, ¹³C, ¹⁵N, ¹⁸O and ³⁴S) of cattle hair?

PubMed

Auerswald, Karl; Rossmann, Andreas; Schäufele, Rudi; Schwertl, Michael; Monahan, Frank J; Schnyder, Hans

2011-12-30

Stable isotope analysis of hair has found applications in many fields of science because it provides a temporally resolved, fairly stable isotopic archive of mammalian individuals. We investigated whether this hair archive is modified by natural weathering while attached to a living animal. We analyzed the tail switch hairs of one suckler cow, sampled seven times over a period of four annual summer pasture-winter stall feeding cycles. We compared relative isotope ratios (δ²H, δ¹³C, δ¹⁵N, δ¹⁸O and δ³⁴S) of sections of hair that grew simultaneously but were exposed to natural weathering conditions over different periods of time. Natural wear caused a loss of mass of approx. 0.13% day⁻¹, with no apparent effect of environmental conditions. Changes in δ²H, δ¹³C, δ¹⁵N and δ¹⁸O were below the detection limit, indicating that hair is a reliable archive for the isotopes of these elements. In contrast, δ³⁴S values increased during the grazing period by about 1‰, with exposure to UV radiation appearing to have a major influence on this result. The δ³⁴S values decreased during the subsequent stall period, probably due to abrasion. Seasonal variation in δ³⁴S may indicate alternating environments that differ in their weathering conditions.

Cognition-emotion interactions: patterns of change and implications for math problem solving

PubMed Central

Trezise, Kelly; Reeve, Robert A.

2014-01-01

Surprisingly little is known about whether relationships between cognitive and emotional states remain stable or change over time, or how different patterns of stability and/or change in the relationships affect problem solving abilities. Nevertheless, cross-sectional studies show that anxiety/worry may reduce working memory (WM) resources, and the ability to minimize the effects anxiety/worry is higher in individuals with greater WM capacity. To investigate the patterns of stability and/or change in cognition-emotion relations over time and their implications for problem solving, 126 14-year-olds’ algebraic WM and worry levels were assessed twice in a single day before completing an algebraic math problem solving test. We used latent transition analysis to identify stability/change in cognition-emotion relations, which yielded a six subgroup solution. Subgroups varied in WM capacity, worry, and stability/change relationships. Among the subgroups, we identified a high WM/low worry subgroup that remained stable over time and a high WM/high worry, and a moderate WM/low worry subgroup that changed to low WM subgroups over time. Patterns of stability/change in subgroup membership predicted algebraic test results. The stable high WM/low worry subgroup performed best and the low WM capacity-high worry “unstable across time” subgroup performed worst. The findings highlight the importance of assessing variations in cognition-emotion relationships over time (rather than assessing cognition or emotion states alone) to account for differences in problem solving abilities. PMID:25132830

Heavy episodic drinking is a trait-state: a cautionary note.

PubMed

Mushquash, Aislin R; Sherry, Simon B; Mackinnon, Sean P; Mushquash, Christopher J; Stewart, Sherry H

2014-01-01

Heavy episodic (binge) drinking is common in and problematic for undergraduates. Researchers often assume that an individual's heavy episodic drinking is stable and trait-like. However, this fails to consider fluctuating, state-like variation in heavy episodic drinking. This study proposes and tests a novel conceptualization of heavy episodic drinking as a trait-state wherein the contribution of both trait-like stability and state-like fluctuations are quantified. It was hypothesized that heavy episodic drinking is a trait-state such that individuals have trait-like tendencies to engage in heavy episodic drinking, and state-like differences in the expression of this tendency over time. A sample of 114 first-year undergraduates from a Canadian university completed self-report measures of heavy episodic drinking at 3 time points across 130 days. Hypotheses were tested with repeated-measures analysis of variance (ANOVA), test-retest correlations, and generalizability theory analyses. A substantial proportion of the variance in heavy episodic drinking is attributable to trait-like stability, with a smaller proportion attributable to state-like fluctuations. The heavy episodic drinker seems characterized by a stable, trait-like tendency to drink in a risky manner, and this trait-like tendency seems to fluctuate in degree of expression over time. Findings complement research suggesting that people have trait-like predispositions that increase their risk for heavy episodic drinking. However, despite this stable tendency to drink heavily, the frequency of heavy episodic drinking appears to be at least partly sporadic or situation dependent. These findings serve as a caution to alcohol researchers and clinicians who often assume that a single assessment of heavy episodic drinking captures a person's usual drinking behavior.

Stable centromere positioning in diverse sequence contexts of complex and satellite centromeres of maize and wild relatives.

PubMed

Gent, Jonathan I; Wang, Na; Dawe, R Kelly

2017-06-21

Paradoxically, centromeres are known both for their characteristic repeat sequences (satellite DNA) and for being epigenetically defined. Maize (Zea mays mays) is an attractive model for studying centromere positioning because many of its large (~2 Mb) centromeres are not dominated by satellite DNA. These centromeres, which we call complex centromeres, allow for both assembly into reference genomes and for mapping short reads from ChIP-seq with antibodies to centromeric histone H3 (cenH3). We found frequent complex centromeres in maize and its wild relatives Z. mays parviglumis, Z. mays mexicana, and particularly Z. mays huehuetenangensis. Analysis of individual plants reveals minor variation in the positions of complex centromeres among siblings. However, such positional shifts are stochastic and not heritable, consistent with prior findings that centromere positioning is stable at the population level. Centromeres are also stable in multiple F1 hybrid contexts. Analysis of repeats in Z. mays and other species (Zea diploperennis, Zea luxurians, and Tripsacum dactyloides) reveals tenfold differences in abundance of the major satellite CentC, but similar high levels of sequence polymorphism in individual CentC copies. Deviation from the CentC consensus has little or no effect on binding of cenH3. These data indicate that complex centromeres are neither a peculiarity of cultivation nor inbreeding in Z. mays. While extensive arrays of CentC may be the norm for other Zea and Tripsacum species, these data also reveal that a wide diversity of DNA sequences and multiple types of genetic elements in and near centromeres support centromere function and constrain centromere positions.

Utilization of Sugarcane Habitat by Feral Pig (Sus scrofa) in Northern Tropical Queensland: Evidence from the Stable Isotope Composition of Hair

PubMed Central

Wurster, Christopher M.; Robertson, Jack; Westcott, David A.; Dryden, Bart; Zazzo, Antoine; Bird, Michael I.

2012-01-01

Feral pigs (Sus scrofa) are an invasive species that disrupt ecosystem functioning throughout their introduced range. In tropical environments, feral pigs are associated with predation and displacement of endangered species, modification of habitat, and act as a vector for the spread of exotic vegetation and disease. Across many parts of their introduced range, the diet of feral pigs is poorly known. Although the remote location and difficult terrain of far north Queensland makes observing feral pig behavior difficult, feral pigs are perceived to seek refuge in World Heritage tropical rainforests and seasonally ‘crop raid’ into lowland sugarcane crops. Thus, identifying how feral pigs are using different components of the landscape is important to the design of management strategies. We used the stable isotope composition of captured feral pigs to determine the extent of rainforest and sugarcane habitat usage. Recently grown hair (basal hair) from feral pigs captured in remote rainforest indicated pigs met their dietary needs solely within this habitat. Stable carbon and nitrogen isotope values of basal hair from feral pigs captured near sugarcane plantations were more variable, with some individuals estimated to consume over 85% of their diet within a sugarcane habitat, while a few consumed as much as 90% of their diet from adjacent forested environments. We estimated whether feral pigs switch habitats by sequentially sampling δ 13C and δ 15N values of long tail hair from a subset of seven captured animals, and demonstrate that four of these individuals moved between habitats. Our results indicate that feral pigs utilize both sugarcane and forest habitats, and can switch between these resources. PMID:22957029

Consequences of the genetic threshold model for observing partial migration under climate change scenarios.

PubMed

Cobben, Marleen M P; van Noordwijk, Arie J

2017-10-01

Migration is a widespread phenomenon across the animal kingdom as a response to seasonality in environmental conditions. Partially migratory populations are populations that consist of both migratory and residential individuals. Such populations are very common, yet their stability has long been debated. The inheritance of migratory activity is currently best described by the threshold model of quantitative genetics. The inclusion of such a genetic threshold model for migratory behavior leads to a stable zone in time and space of partially migratory populations under a wide range of demographic parameter values, when assuming stable environmental conditions and unlimited genetic diversity. Migratory species are expected to be particularly sensitive to global warming, as arrival at the breeding grounds might be increasingly mistimed as a result of the uncoupling of long-used cues and actual environmental conditions, with decreasing reproduction as a consequence. Here, we investigate the consequences for migratory behavior and the stability of partially migratory populations under five climate change scenarios and the assumption of a genetic threshold value for migratory behavior in an individual-based model. The results show a spatially and temporally stable zone of partially migratory populations after different lengths of time in all scenarios. In the scenarios in which the species expands its range from a particular set of starting populations, the genetic diversity and location at initialization determine the species' colonization speed across the zone of partial migration and therefore across the entire landscape. Abruptly changing environmental conditions after model initialization never caused a qualitative change in phenotype distributions, or complete extinction. This suggests that climate change-induced shifts in species' ranges as well as changes in survival probabilities and reproductive success can be met with flexibility in migratory behavior at the species level, which will reduce the risk of extinction.

Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter

PubMed Central

Trathan, Philip N.; Ceia, Filipe R.; Tarling, Geraint A.; Adlard, Stacey; Fox, Derren; Edwards, Ewan W. J.; Vieira, Rui P.; Medeiros, Renata; De Broyer, Claude; Cherel, Yves

2017-01-01

Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the “Intersexual Competition Hypothesis” for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do), in that they have a wider habitat and trophic niche during the Antarctic Winter (in comparison to Summer). We also detected individual specialization in feeding/trophic levels for each gender, with certain males feeding mainly on fish and certain females mainly on crustaceans, which may be driven the prevailing environmental conditions that lead individuals to search for alternative prey, and cause sexual diet segregation. Our results provide further information to help improve understanding about sexual segregation and individual specialization of marine organisms, while contributing valuable information on the winter diet for Antarctic monitoring programs and for modelling Antarctic marine food webs. PMID:28362847

Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter.

PubMed

Xavier, José C; Trathan, Philip N; Ceia, Filipe R; Tarling, Geraint A; Adlard, Stacey; Fox, Derren; Edwards, Ewan W J; Vieira, Rui P; Medeiros, Renata; De Broyer, Claude; Cherel, Yves

2017-01-01

Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the "Intersexual Competition Hypothesis" for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do), in that they have a wider habitat and trophic niche during the Antarctic Winter (in comparison to Summer). We also detected individual specialization in feeding/trophic levels for each gender, with certain males feeding mainly on fish and certain females mainly on crustaceans, which may be driven the prevailing environmental conditions that lead individuals to search for alternative prey, and cause sexual diet segregation. Our results provide further information to help improve understanding about sexual segregation and individual specialization of marine organisms, while contributing valuable information on the winter diet for Antarctic monitoring programs and for modelling Antarctic marine food webs.

Desert Tortoise (Gopherus agassizii) Dietary Specialization Decreases across a Precipitation Gradient

PubMed Central

Murray, Ian W.; Wolf, Blair O.

2013-01-01

We studied the plant resource use between and within populations of desert tortoise (Gopherus agassizii) across a precipitation gradient in the Sonoran Desert of Arizona. The carbon and nitrogen stable isotope values in animal tissues are a reflection of the carbon and nitrogen isotope values in diet, and consequently represent a powerful tool to study animal feeding ecology. We measured the δ13C and δ15N values in the growth rings on the shells of tortoises in different populations to characterize dietary specialization and track tortoise use of isotopically distinct C4/CAM versus C3 plant resources. Plants using C3 photosynthesis are generally more nutritious than C4 plants and these trait differences can have important growth and fitness consequences for consumers. We found that dietary specialization decreases in successively drier and less vegetated sites, and that broader population niche widths are accompanied by an increase in the dietary variability between individuals. Our results highlight how individual consumer plant resource use is bounded under a varying regime of precipitation and plant productivity, lending insight into how intra-individual dietary specialization varies over a spatial scale of environmental variability. PMID:23840495

Problem-solving and learning in Carib grackles: individuals show a consistent speed-accuracy trade-off.

PubMed

Ducatez, S; Audet, J N; Lefebvre, L

2015-03-01

The generation and maintenance of within-population variation in cognitive abilities remain poorly understood. Recent theories propose that this variation might reflect the existence of consistent cognitive strategies distributed along a slow-fast continuum influenced by shyness. The slow-fast continuum might be reflected in the well-known speed-accuracy trade-off, where animals cannot simultaneously maximise the speed and the accuracy with which they perform a task. We test this idea on 49 wild-caught Carib grackles (Quiscalus lugubris), a tame opportunistic generalist Icterid bird in Barbados. Grackles that are fast at solving novel problems involving obstacle removal to reach visible food perform consistently over two different tasks, spend more time per trial attending to both tasks, and are those that show more shyness in a pretest. However, they are also the individuals that make more errors in a colour discrimination task requiring no new motor act. Our data reconcile some of the mixed positive and negative correlations reported in the comparative literature on cognitive tasks, suggesting that a speed-accuracy trade-off could lead to negative correlations between tasks favouring speed and tasks favouring accuracy, but still reveal consistent strategies based on stable individual differences.

Divergence of a stereotyped call in northern resident killer whales.

PubMed

Grebner, Dawn M; Parks, Susan E; Bradley, David L; Miksis-Olds, Jennifer L; Capone, Dean E; Ford, John K B

2011-02-01

Northern resident killer whale pods (Orcinus orca) have distinctive stereotyped pulsed call repertoires that can be used to distinguish groups acoustically. Repertoires are generally stable, with the same call types comprising the repertoire of a given pod over a period of years to decades. Previous studies have shown that some discrete pulsed calls can be subdivided into variants or subtypes. This study suggests that new stereotyped calls may result from the gradual modification of existing call types through subtypes. Vocalizations of individuals and small groups of killer whales were collected using a bottom-mounted hydrophone array in Johnstone Strait, British Columbia in 2006 and 2007. Discriminant analysis of slope variations of a predominant call type, N4, revealed the presence of four distinct call subtypes. Similar to previous studies, there was a divergence of the N4 call between members of different matrilines of the same pod. However, this study reveals that individual killer whales produced multiple subtypes of the N4 call, indicating that divergence in the N4 call is not the result of individual differences, but rather may indicate the gradual evolution of a new stereotyped call.

Variable threshold algorithm for division of labor analyzed as a dynamical system.

PubMed

Castillo-Cagigal, Manuel; Matallanas, Eduardo; Navarro, Iñaki; Caamaño-Martín, Estefanía; Monasterio-Huelin, Félix; Gutiérrez, Álvaro

2014-12-01

Division of labor is a widely studied aspect of colony behavior of social insects. Division of labor models indicate how individuals distribute themselves in order to perform different tasks simultaneously. However, models that study division of labor from a dynamical system point of view cannot be found in the literature. In this paper, we define a division of labor model as a discrete-time dynamical system, in order to study the equilibrium points and their properties related to convergence and stability. By making use of this analytical model, an adaptive algorithm based on division of labor can be designed to satisfy dynamic criteria. In this way, we have designed and tested an algorithm that varies the response thresholds in order to modify the dynamic behavior of the system. This behavior modification allows the system to adapt to specific environmental and collective situations, making the algorithm a good candidate for distributed control applications. The variable threshold algorithm is based on specialization mechanisms. It is able to achieve an asymptotically stable behavior of the system in different environments and independently of the number of individuals. The algorithm has been successfully tested under several initial conditions and number of individuals.

Real beards and real networks: a spin-glass model for interacting individuals

NASA Astrophysics Data System (ADS)

O'Neale, Dion

''I want to be different, just like all the other different people'' sang the band King Missile. Whether they are the Beatniks of the 1950s, the punks of the 1970s, or the hipsters of today, non-conformists often tend to look the same, seemingly at odds with their goal of non-conformity. The spin-glass model, originally developed to describe the interaction of magnetic spins, and since applied to situations as diverse as the electrical activity of networks of neurons, to trades on a financial market, has recently been used in social science to study populations of interacting individuals comprised of a mix of both conformists and anti-conformists - or hipsters. Including delay effects for the interactions between individuals has been shown to give a system with non-trivial dynamics with a phase transition from stable behaviour to periodic switching between two states (let's call them bushy bearded and clean shaven). Analytic solutions to such a model are possible, but only for particular assumptions about the interaction and delay matrices. In this work we will show what happens when the interactions in the model are based on real-world networks with ''small-world'' effects and clustering.

Moderators of the Dynamic Link between Alcohol Use and Aggressive Behavior among Adolescent Males

PubMed Central

White, Helene Raskin; Fite, Paula; Pardini, Dustin; Mun, Eun-Young; Loeber, Rolf

2012-01-01

Although longitudinal evidence has linked alcohol use with aggressive behavior during adolescence, most studies have failed to adequately control for the numerous between-individual differences that may underlie this association. In addition, few studies of adolescents have examined whether the nature of the within-individual association between alcohol use and aggression depends on individual and contextual factors. To address these limitations, this study examined the association between within-individual changes in alcohol use and aggressive behavior across adolescence and determined whether impulsive behavior, positive attitudes toward violence, violent peers, neighborhood crime, and race moderated this association. Data from 971 adolescent males assessed annually from ages 13 to 18 were analyzed using a within-individual regression panel model that eliminated all stable between-individual factors as potential confounds. Findings indicated that within-individual increases in alcohol use quantity from one’s own typical levels of drinking were concurrently associated with within-individual increases in aggressive behavior, and vice versa. However, increases in alcohol were more strongly linked to increases in aggressive behavior among boys with attitudes favoring violence and those who lived in high-crime neighborhoods. The association between alcohol and aggressive behavior was similar for White and Black young men. Interventions designed to reduce aggressive behaviors should consider targeting not only alcohol use, but also individual and environmental risk factors that contribute to this link. PMID:22911129

Biological auctions with multiple rewards

PubMed Central

Reiter, Johannes G.; Kanodia, Ayush; Gupta, Raghav; Nowak, Martin A.; Chatterjee, Krishnendu

2015-01-01

The competition for resources among cells, individuals or species is a fundamental characteristic of evolution. Biological all-pay auctions have been used to model situations where multiple individuals compete for a single resource. However, in many situations multiple resources with various values exist and single reward auctions are not applicable. We generalize the model to multiple rewards and study the evolution of strategies. In biological all-pay auctions the bid of an individual corresponds to its strategy and is equivalent to its payment in the auction. The decreasingly ordered rewards are distributed according to the decreasingly ordered bids of the participating individuals. The reproductive success of an individual is proportional to its fitness given by the sum of the rewards won minus its payments. Hence, successful bidding strategies spread in the population. We find that the results for the multiple reward case are very different from the single reward case. While the mixed strategy equilibrium in the single reward case with more than two players consists of mostly low-bidding individuals, we show that the equilibrium can convert to many high-bidding individuals and a few low-bidding individuals in the multiple reward case. Some reward values lead to a specialization among the individuals where one subpopulation competes for the rewards and the other subpopulation largely avoids costly competitions. Whether the mixed strategy equilibrium is an evolutionarily stable strategy (ESS) depends on the specific values of the rewards. PMID:26180069

A piecewise smooth model of evolutionary game for residential mobility and segregation

NASA Astrophysics Data System (ADS)

Radi, D.; Gardini, L.

2018-05-01

The paper proposes an evolutionary version of a Schelling-type dynamic system to model the patterns of residential segregation when two groups of people are involved. The payoff functions of agents are the individual preferences for integration which are empirically grounded. Differently from Schelling's model, where the limited levels of tolerance are the driving force of segregation, in the current setup agents benefit from integration. Despite the differences, the evolutionary model shows a dynamics of segregation that is qualitatively similar to the one of the classical Schelling's model: segregation is always a stable equilibrium, while equilibria of integration exist only for peculiar configurations of the payoff functions and their asymptotic stability is highly sensitive to parameter variations. Moreover, a rich variety of integrated dynamic behaviors can be observed. In particular, the dynamics of the evolutionary game is regulated by a one-dimensional piecewise smooth map with two kink points that is rigorously analyzed using techniques recently developed for piecewise smooth dynamical systems. The investigation reveals that when a stable internal equilibrium exists, the bimodal shape of the map leads to several different kinds of bifurcations, smooth, and border collision, in a complicated interplay. Our global analysis can give intuitions to be used by a social planner to maximize integration through social policies that manipulate people's preferences for integration.

Food and social complexity at Çayönü Tepesi, southeastern Anatolia: Stable isotope evidence of differentiation in diet according to burial practice and sex in the early Neolithic

PubMed Central

Pearson, Jessica; Grove, Matt; Özbek, Metin; Hongo, Hitomi

2013-01-01

The identification of early social complexity and differentiation in early village societies has been approached in the past most notably through the evaluation of rituals and architectural layouts. Such studies could be complemented by an approach that provides data about everyday behaviours of individuals. We took 540 human and animal bone samples for stable carbon and nitrogen isotope analysis from the Neolithic site of Çayönü Tepesi in southeastern Anatolia. The inhabitants at this site chose to bury their dead in two different ways at different times during its occupation: beneath the floors of their houses, but also inside a public mortuary building known as the Skull Building. This variation provides an opportunity using isotope methods to test whether there was evidence for structuring of daily activities (diet in this case) that might serve to reinforce this change in burial practice. We show that when the inhabitants of Çayönü Tepesi changed their architecture and operated different burial practices in conjunction, this coincided with other aspects of behaviour including socially-constituted food consumption practices, which served to reinforce social identities. PMID:24976671

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

Cantone, M.C.

The interest in biokinetic studies is driven by problems related to the physiopathology of oligoelements, chemical elemental pollution and radioactive release in case of nuclear accidents. The application of stable isotopes as tracers in studies of trace elements in the area of nutritional and food science is particularly attractive and specifically if considering the investigations on the most radiosensitive age groups of the population and the repeated studies on healthy people for the assessment of the bioavailability of different compounds. A tracer method based on stable isotope administration, which combines the simultaneous use of two tracers and proton activation analysismore » is presented. A study aimed to obtain molybdenum biokinetic data in humans was performed. One tracer ({sup 96}Mo) was orally administered and another ({sup 95}Mo) was intravenously injected to two fasting volunteer subjects. Venous blood samples were withdrawn at different postinjection times. The concentration in plasma for both the isotopes was determined by measuring the intensities of the gamma-lines from the technetium radioisotopes produced via (p,n) reactions. In the adopted experimental conditions a minimum detectable concentration of 2 ng isotope/ml plasma was attained. The parameters describing molybdenum kinetics were obtained for the two individuals. Moreover, the investigation was repeated with different tracer amounts for one of the two subjects, in both fasting and non-fasting condition.« less

Patterns and sources of personality development in old age.

PubMed

Kandler, Christian; Kornadt, Anna E; Hagemeyer, Birk; Neyer, Franz J

2015-07-01

Despite abundant evidence that personality development continues in adulthood, little is known about the patterns and sources of personality development in old age. We thus investigated mean-level trends and individual differences in change as well as the genetic and environmental sources of rank-order continuity and change in several personality traits (neuroticism, extraversion, openness, agreeableness, conscientiousness, perceived control, and affect intensity) and well-being. In addition, we analyzed the interrelation between perceived control and change in other personality traits as well as between change in personality traits and change in well-being. We analyzed data from older adult twins, aged 64-85 years at Time 1 (N = 410; 135 males and 275 females; 134 monozygotic and 63 dizygotic twin pairs), collected at 2 different time points about 5 years apart. On average, neuroticism increased, whereas extraversion, conscientiousness, and perceived control significantly decreased over time. Change in perceived control was associated with change in neuroticism and conscientiousness, pointing to particular adaptation mechanisms specific to old age. Whereas individual differences in personality traits were fairly stable due to both genetic and environmental sources, individual differences in change were primarily due to environmental sources (beyond random error) indicating plasticity in old age. Even though the average level of well-being did not significantly change over time, individual well-being tended to decrease with strongly increasing levels of neuroticism as well as decreasing extraversion, conscientiousness, and perceived control, indicating that personality traits predict well-being but not vice versa. We discuss implications for theory on personality development across the lifespan. (c) 2015 APA, all rights reserved).

Emotional Granularity Effects on Event-Related Brain Potentials during Affective Picture Processing

PubMed Central

Lee, Ja Y.; Lindquist, Kristen A.; Nam, Chang S.

2017-01-01

There is debate about whether emotional granularity, the tendency to label emotions in a nuanced and specific manner, is merely a product of labeling abilities, or a systematic difference in the experience of emotion during emotionally evocative events. According to the Conceptual Act Theory of Emotion (CAT) (Barrett, 2006), emotional granularity is due to the latter and is a product of on-going temporal differences in how individuals categorize and thus make meaning of their affective states. To address this question, the present study investigated the effects of individual differences in emotional granularity on electroencephalography-based brain activity during the experience of emotion in response to affective images. Event-related potentials (ERP) and event-related desynchronization and synchronization (ERD/ERS) analysis techniques were used. We found that ERP responses during the very early (60–90 ms), middle (270–300 ms), and later (540–570 ms) moments of stimulus presentation were associated with individuals’ level of granularity. We also observed that highly granular individuals, compared to lowly granular individuals, exhibited relatively stable desynchronization of alpha power (8–12 Hz) and synchronization of gamma power (30–50 Hz) during the 3 s of stimulus presentation. Overall, our results suggest that emotional granularity is related to differences in neural processing throughout emotional experiences and that high granularity could be associated with access to executive control resources and a more habitual processing of affective stimuli, or a kind of “emotional complexity.” Implications for models of emotion are also discussed. PMID:28392761

Seasonal variations in the stable oxygen isotope ratio of wood cellulose reveal annual rings of trees in a Central Amazon terra firme forest.

PubMed

Ohashi, Shinta; Durgante, Flávia M; Kagawa, Akira; Kajimoto, Takuya; Trumbore, Susan E; Xu, Xiaomei; Ishizuka, Moriyoshi; Higuchi, Niro

2016-03-01

In Amazonian non-flooded forests with a moderate dry season, many trees do not form anatomically definite annual rings. Alternative indicators of annual rings, such as the oxygen (δ(18)Owc) and carbon stable isotope ratios of wood cellulose (δ(13)Cwc), have been proposed; however, their applicability in Amazonian forests remains unclear. We examined seasonal variations in the δ(18)Owc and δ(13)Cwc of three common species (Eschweilera coriacea, Iryanthera coriacea, and Protium hebetatum) in Manaus, Brazil (Central Amazon). E. coriacea was also sampled in two other regions to determine the synchronicity of the isotopic signals among different regions. The annual cyclicity of δ(18)Owc variation was cross-checked by (14)C dating. The δ(18)Owc showed distinct seasonal variations that matched the amplitude observed in the δ(18)O of precipitation, whereas seasonal δ(13)Cwc variations were less distinct in most cases. The δ(18)Owc variation patterns were similar within and between some individual trees in Manaus. However, the δ(18)Owc patterns of E. coriacea differed by region. The ages of some samples estimated from the δ(18)Owc cycles were offset from the ages estimated by (14)C dating. In the case of E. coriacea, this phenomenon suggested that missing or wedging rings may occur frequently even in well-grown individuals. Successful cross-dating may be facilitated by establishing δ(18)Owc master chronologies at both seasonal and inter-annual scales for tree species with distinct annual rings in each region.

Paid and unpaid working hours among Swedish men and women in relation to depressive symptom trajectories: results from four waves of the Swedish Longitudinal Occupational Survey of Health.

PubMed

Peristera, Paraskevi; Westerlund, Hugo; Magnusson Hanson, Linda L

2018-06-07

Long working hours and unpaid work are possible risk factors for depressive symptoms. However, little is known about how working hours influence the course of depressive symptoms. This study examined the influence of paid, unpaid working hours and total working hours on depressive symptoms trajectories. The study was based on data from four waves of the Swedish Longitudinal Occupational Survey of Health (SLOSH 2008-2014). We applied group-based trajectory modelling in order to identify trajectories of depressive symptoms and studied paid and unpaid working hours and total working hours as risk factors. Six trajectory groups were identified with symptoms: 'very low stable', 'low stable', 'doubtful increasing', 'high decreasing', 'mild decreasing' and 'high stable'. More time spent on unpaid work was associated with the 'low stable' (OR 1.16, 95% CI 1.04 to 1.30) and the 'high stable (OR 1.40, 95% CI 1.18 to 1.65) symptom trajectories compared with being in the 'very low stable' symptom group. In addition, more total working hours was associated with a higher probability of having 'high decreasing' (OR 1.30, 95% CI 1.14 to 1.48) and 'high stable' (OR 1.22, 95% CI 1.01 to 1.47) symptoms, when adjusting for sex, age, civil status and socioeconomic status. The results, however, differed somewhat for men and women. More unpaid working hours was more clearly associated with higher symptom trajectories among women. More total working hours was associated with 'high stable' symptoms among women only. This study supported heterogeneous individual patterns of depressive symptoms over time among the Swedish working population. The results also indicate that a higher burden of unpaid work and longer total working hours, which indicate a double burden from paid and unpaid work, may be associated with higher depressive symptom trajectories, especially among women. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Stable isotopes identify dietary changes associated with beak deformities in Black-Capped Chickadees (Poecile atricapillus)

USGS Publications Warehouse

Van Hemert, Caroline; Handel, Colleen M.; O'Brien, Diane M.

2012-01-01

A large number of beak deformities of unknown etiology have recently been reported in Black-capped Chickadees (Poecile atricapillus) and other resident avian species in Alaska. We investigated the potential association between diet and beak deformities. We analyzed carbon (δ13C) and nitrogen (δ15N) isotopes in whole blood of Black-capped Chickadees captured at three semiurban sites in south-central Alaska. For dietary analysis, we included natural foods (arthropods, seeds, and berries) and anthropogenic items commonly provided in bird feeders (sunflower seeds, peanut butter, and suet). Blood samples from individuals with beak deformities exhibited lower δ15N values and more variable δ13C values than birds with normal beaks. Isotopic values of blood also differed by location for both carbon and nitrogen, but we did not detect a difference in natural dietary items across the three sites. Contributions of individual diet items differed between birds with and without beak deformities, a pattern that likely reflected reduced function of the beak. Affected birds generally consumed fewer arthropods and sunflower seeds and more peanut butter and natural seeds and berries. Although some individuals with beak deformities relied heavily on feeder foods, we did not find evidence of an anthropogenic food source shared by all affected birds. In addition, dietary differences were most pronounced for moderately to severely affected birds, which suggests that these differences are more likely to be a consequence than a cause of deformities.

The role of personality in task and relationship conflict.

PubMed

Bono, Joyce E; Boles, Terry L; Judge, Timothy A; Lauver, Kristy J

2002-06-01

Two studies explored the extent to which dispositions influence the attributions individuals make about the type of conflict they experience. Traits from the Five-Factor Model of personality (FFM) were linked to the tendency to experience task-and relationship-oriented conflict. Results provide some support for the idea that individuals have stable tendencies in the attributions they make about their conflict experiences across time, partners, and situations. Agreeableness and openness were related to reports of relationship conflict at the individual level. However, the strongest effects of personality on conflict attributions were found in the analysis of dyads. This analysis revealed that partner levels of extraversion and conscientiousness were associated with individuals' tendencies to report relationship conflict. Moreover, mean levels of extraversion and conscientiousness in a pair were associated with reports of relationship conflict. Differences between partners in extraversion were associated with more frequent conflict and a greater likelihood of reporting task-related conflict. Implications of these findings with respect to the role of personality in interpersonal relationships are discussed. Finally, these studies provide confirmatory evidence that conflict attributions have a meaningful impact on relationship satisfaction.

Reconsideration of r/K Selection Theory Using Stochastic Control Theory and Nonlinear Structured Population Models.

PubMed

Oizumi, Ryo; Kuniya, Toshikazu; Enatsu, Yoichi

2016-01-01

Despite the fact that density effects and individual differences in life history are considered to be important for evolution, these factors lead to several difficulties in understanding the evolution of life history, especially when population sizes reach the carrying capacity. r/K selection theory explains what types of life strategies evolve in the presence of density effects and individual differences. However, the relationship between the life schedules of individuals and population size is still unclear, even if the theory can classify life strategies appropriately. To address this issue, we propose a few equations on adaptive life strategies in r/K selection where density effects are absent or present. The equations detail not only the adaptive life history but also the population dynamics. Furthermore, the equations can incorporate temporal individual differences, which are referred to as internal stochasticity. Our framework reveals that maximizing density effects is an evolutionarily stable strategy related to the carrying capacity. A significant consequence of our analysis is that adaptive strategies in both selections maximize an identical function, providing both population growth rate and carrying capacity. We apply our method to an optimal foraging problem in a semelparous species model and demonstrate that the adaptive strategy yields a lower intrinsic growth rate as well as a lower basic reproductive number than those obtained with other strategies. This study proposes that the diversity of life strategies arises due to the effects of density and internal stochasticity.

Change and Stability in Religiousness and Spirituality in Emerging Adulthood.

PubMed

Koenig, Laura B

2015-01-01

The author investigated the change and stability of different aspects of religiousness and spirituality, as well as whether personality traits may help explain why individuals increase or decrease in religiousness and spirituality during emerging adulthood. Self-report measures of childhood and current religiousness were completed by 224 college-aged participants. A subset of participants also completed a measure of personality and measures of religious and spiritual belief trajectories by rating the importance of each belief at successive age brackets across their lifespan. Analyses of mean-level, rank-order, and individual-level stability and change in religiousness indicated that while average religiousness scores decreased, there was still moderate to high rank-order stability in scores. Additionally, service attendance was less stable and decreased more than importance of religion in daily life. Examination of the trajectories of religiousness and spirituality over time showed similar differences: religiousness decreased, on average, whereas spirituality increased slightly, but significantly, across successive age brackets. Personality traits did not significantly predict change in religiousness over time, although openness predicted change in spirituality. Conclusions include the idea that religiousness in emerging adulthood is comprised on different components that change at different rates.

Stable isotope series from elephant ivory reveal lifetime histories of a true dietary generalist

PubMed Central

Codron, Jacqueline; Codron, Daryl; Sponheimer, Matt; Kirkman, Kevin; Duffy, Kevin J.; Raubenheimer, Erich J.; Mélice, Jean-Luc; Grant, Rina; Clauss, Marcus; Lee-Thorp, Julia A.

2012-01-01

Longitudinal studies have revealed how variation in resource use within consumer populations can impact their dynamics and functional significance in communities. Here, we investigate multi-decadal diet variations within individuals of a keystone megaherbivore species, the African elephant (Loxodonta africana), using serial stable isotope analysis of tusks from the Kruger National Park, South Africa. These records, representing the longest continuous diet histories documented for any extant species, reveal extensive seasonal and annual variations in isotopic—and hence dietary—niches of individuals, but little variation between them. Lack of niche distinction across individuals contrasts several recent studies, which found relatively high levels of individual niche specialization in various taxa. Our result is consistent with theory that individual mammal herbivores are nutritionally constrained to maintain broad diet niches. Individual diet specialization would also be a costly strategy for large-bodied taxa foraging over wide areas in spatio-temporally heterogeneous environments. High levels of within-individual diet variability occurred within and across seasons, and persisted despite an overall increase in inferred C4 grass consumption through the twentieth century. We suggest that switching between C3 browsing and C4 grazing over extended time scales facilitates elephant survival through environmental change, and could even allow recovery of overused resources. PMID:22337695

Stable isotope series from elephant ivory reveal lifetime histories of a true dietary generalist.

PubMed

Codron, Jacqueline; Codron, Daryl; Sponheimer, Matt; Kirkman, Kevin; Duffy, Kevin J; Raubenheimer, Erich J; Mélice, Jean-Luc; Grant, Rina; Clauss, Marcus; Lee-Thorp, Julia A

2012-06-22

Longitudinal studies have revealed how variation in resource use within consumer populations can impact their dynamics and functional significance in communities. Here, we investigate multi-decadal diet variations within individuals of a keystone megaherbivore species, the African elephant (Loxodonta africana), using serial stable isotope analysis of tusks from the Kruger National Park, South Africa. These records, representing the longest continuous diet histories documented for any extant species, reveal extensive seasonal and annual variations in isotopic--and hence dietary--niches of individuals, but little variation between them. Lack of niche distinction across individuals contrasts several recent studies, which found relatively high levels of individual niche specialization in various taxa. Our result is consistent with theory that individual mammal herbivores are nutritionally constrained to maintain broad diet niches. Individual diet specialization would also be a costly strategy for large-bodied taxa foraging over wide areas in spatio-temporally heterogeneous environments. High levels of within-individual diet variability occurred within and across seasons, and persisted despite an overall increase in inferred C(4) grass consumption through the twentieth century. We suggest that switching between C(3) browsing and C(4) grazing over extended time scales facilitates elephant survival through environmental change, and could even allow recovery of overused resources.

Religious Belief and Practice: New Forces in American Politics?

ERIC Educational Resources Information Center

Beatty, Kathleen Murphy; Walter, Oliver

Exploratory research suggests that denominational preferences, fundamentalism, and church attendance are related to an individual's position on political issues. A review of research reveals that religious beliefs are stable, developed early in life, and are central to an individual's other orientations. Research on religious orientation is…

Dental disease and dietary isotopes of individuals from St Gertrude Church cemetery, Riga, Latvia.

PubMed

Petersone-Gordina, Elina; Roberts, Charlotte; Millard, Andrew R; Montgomery, Janet; Gerhards, Guntis

2018-01-01

This research explores oral health indicators and stable carbon and nitrogen isotope data to explore diet, and differences in diet, between people buried in the four different contexts of the St Gertrude Church cemetery (15th- 17th centuries AD): the general cemetery, two mass graves, and a collective mass burial pit within the general cemetery. The main aim is to assess whether people buried in the mass graves were rural immigrants, or if they were more likely to be the victims of plague (or another epidemic) who lived in Riga and its suburbs. The data produced (from dental disease assessments and isotope analyses) were compared within, as well as between, the contexts. Most differences emerged when comparing the prevalence rates of dental diseases and other oral health indicators in males and females between the contexts, while isotope analysis revealed more individual, rather than context-specific, differences. The data suggested that the populations buried in the mass graves were different from those buried in the general cemetery, and support the theory that rural immigrants were buried in both mass graves. Significant differences were observed in some aspects of the data between the mass graves, however, possibly indicating that the people buried in them do not represent the same community.

Dental disease and dietary isotopes of individuals from St Gertrude Church cemetery, Riga, Latvia

PubMed Central

Roberts, Charlotte; Millard, Andrew R.; Montgomery, Janet; Gerhards, Guntis

2018-01-01

This research explores oral health indicators and stable carbon and nitrogen isotope data to explore diet, and differences in diet, between people buried in the four different contexts of the St Gertrude Church cemetery (15th– 17th centuries AD): the general cemetery, two mass graves, and a collective mass burial pit within the general cemetery. The main aim is to assess whether people buried in the mass graves were rural immigrants, or if they were more likely to be the victims of plague (or another epidemic) who lived in Riga and its suburbs. The data produced (from dental disease assessments and isotope analyses) were compared within, as well as between, the contexts. Most differences emerged when comparing the prevalence rates of dental diseases and other oral health indicators in males and females between the contexts, while isotope analysis revealed more individual, rather than context-specific, differences. The data suggested that the populations buried in the mass graves were different from those buried in the general cemetery, and support the theory that rural immigrants were buried in both mass graves. Significant differences were observed in some aspects of the data between the mass graves, however, possibly indicating that the people buried in them do not represent the same community. PMID:29364968

Stable isotopes differentiate bottlenose dolphins off west-central Florida

USGS Publications Warehouse

Barros, Nélio B.; Ostrom, P. H.; Stricker, Craig A.; Wells, R.S.

2010-01-01

Distinguishing discrete population units among continuously distributed coastal small cetaceans is challenging and crucial to conservation. We evaluated the utility of stable isotopes in assessing group membership in bottlenose dolphins (Tursiops truncatus) off west-central Florida by analyzing carbon, nitrogen, and sulfur isotope values (δ13C, δ15N, and δ34S) of tooth collagen from stranded dolphins. Individuals derived from three putative general population units: Sarasota Bay (SB), nearshore Gulf of Mexico (GULF), and offshore waters (OFF). Animals of known history (SB) served to ground truth the approach against animals of unknown history from the Gulf of Mexico (GULF, OFF). Dolphin groups differed significantly for each isotope. Average δ13C values from SB dolphins (−10.6‰) utilizing sea grass ecosystems differed from those of GULF (−11.9‰) and OFF (−11.9‰). Average δ15N values of GULF (12.7‰) and OFF (13.2‰) were higher than those of SB dolphins (11.9‰), consistent with differences in prey trophic levels. δ34S values showed definitive differences among SB (7.1‰), GULF (11.3‰), and OFF (16.5‰) dolphins. This is the first application of isotopes to population assignment of bottlenose dolphins in the Gulf of Mexico and results suggest that isotopes may provide a powerful tool in the conservation of small cetaceans.

Gas and particle concentrations in horse stables with individual boxes as a function of the bedding material and the mucking regimen.

PubMed

Fleming, K; Hessel, E F; Van den Weghe, H F A

2009-11-01

The aim of this study was to compare different types of bedding and mucking regimens used in horse stables on the generation of airborne particulate matter <10 microm (PM10) and 3 biogenic gases (carbon dioxide, nitrous oxide, and especially ammonia). Three separate experiments were undertaken. The experiments were carried out in an enclosed stable (9.7 m long, 8.7 m wide, and 3.5 m high) that had 5 single boxes housing 4 horses. The measuring instruments were set up in the middle of one side of the stable. In Exp. 1, 3 types of bedding material (wheat straw, straw pellets, and wood shavings) used for horses were assessed according to their ammonia generation. Each type of bedding was used for 2 wk, with 3 repetitions. The mean ammonia concentrations within the stable were 3.07 +/- 0.23 mg/m(3) for wheat straw, 4.79 +/- 0.23 mg/m(3) for straw pellets, and 4.27 +/- 0.17 mg/m(3) for wood shavings. In Exp. 2, the effects of the mucking regimen on the generation of ammonia and PM10 from wheat straw (the bedding with the least ammonia generation in the previous experiment) were examined using 3 different daily regimens: 1) no mucking out, 2) complete mucking out, and 3) partial mucking out (removing only feces). The mean ammonia concentrations in the stable differed significantly among all 3 mucking regimens (P < 0.05). The greatest values were recorded when the stalls were mucked out completely every day [least squares means (LSM) = 2.25 +/- 0.1 mg/m(3)]. No mucking out resulted in an LSM of 1.92 +/- 0.1 mg of ammonia/m(3), whereas an LSM of 1.54 +/- 0.1 mg of ammonia/m(3) was found when the partial mucking out method was used. No mucking out also resulted in significantly less average PM10 (124.4 +/- 13.4 microg/m(3)) than in the other 2 regimens (P < 0.05). In Exp. 3, a 6-wk bedding regimen without mucking out was evaluated with regard to gas and airborne particle generation. The ammonia values were found not to increase constantly during the course of the 6-wk period. The average weekly values for PM10 also did not increase constantly but varied between approximately 90 and 140 microg/m. It can be concluded from the particle and gas generation patterns found in the results of all 3 experiments that wheat straw was the most suitable bedding of the 3 types investigated and that mucking out completely on a daily basis should not be undertaken in horse stables.

2014 status of the Lake Ontario lower trophic levels

USGS Publications Warehouse

Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana; Connerton, Michael J.; LaPan, Steve; Biesinger, Zy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

2015-01-01

Soluble reactive phosphorus (SRP) concentrations have been stable in nearshore and offshore habitats since 1998 (0.4 – 3.3 μg/L). SRP concentrations were low in 2014; Apr/May – Oct mean values were <1 μg/L at most sites. Spring TP concentrations at individual sites exceeded 10 μg/L on occasion, but spring means were below the 10 μg/L target set by the Great Lakes Water Quality Agreement of 1978 for offshore waters of Lake Ontario. TP concentrations were low at both nearshore and offshore locations; Apr/May – Oct mean values from individual sites ranged from 4.6 – 9.1 μg/L. Spring TP has declined significantly in the longer data series (since 1981), but not since 1995 indicating stable nutrient loading into Lake Ontario for nearly two decades. It averaged 7.8 μg/L in the nearshore and 5.6 μg/L in the offshore in 2014.Chlorophyll-a and secchi depth values are indicative of oligotrophic conditions in nearshore and offshore habitats. Offshore summer chlorophyll-a declined significantly in both the short- (2000-2014) and long-term (1981-2014) time series at a rate of 4-6% per year. Nearshore chlorophyll-a increased after 2003 but then declined again after 2009. Epilimnetic chlorophyll-a averaged between 0.6 and 1.6 μg/L across sites with no difference between nearshore and offshore habitats. Apr/May – Oct Secchi depth ranged from 4.0 m to 10.8 m at individual sites and was higher in the offshore (average 9.1 m) than nearshore (5.9 m).In 2014, Apr/May – Oct epilimnetic zooplankton density, size, and biomass were not different between the offshore and the nearshore, and there were no differences in epilimnetic biomass between offshore and nearshore areas for any of the zooplankton groups.Zooplankton density and biomass peaked in September, an atypical pattern. This coincided with peaks in calanoid copepod, daphnid, and Holopedium biomass. Holopedium biomass in the nearshore increased significantly since 1995.The predatory cladoceran Cercopagis continued to be abundant in the summer, peaking at ~10 mg/m3in the offshore. Bythotrephes biomass was at its lowest level since 2005 in both offshore and nearshore habitats.Summer nearshore zooplankton density and biomass have declined significantly since 1995 at rates of 9-10% per year but have remained stable since 2005. However, bosminids and daphnids increased in 2013 and 2014.Summer offshore zooplankton density and biomass declined significantly in the long-term (since 1981), but remained at a lower stable level 2000 – 2014. A positive change point in 2013 is due to increases in bosminids, cyclopoid copepods, and daphnids.The observed decline in zooplankton biomass may be due in part to redistribution of zooplankton throughout the water column. Most of the zooplankton biomass was in the metalimnion and hypolimnion during the stratified period in 2014. By October, the bulk of the biomass was in the epilimnion.

Seasonal distribution and abundance of cetaceans within French waters- Part II: The Bay of Biscay and the English Channel

NASA Astrophysics Data System (ADS)

Laran, Sophie; Authier, Matthieu; Blanck, Aurélie; Doremus, Ghislain; Falchetto, Hélène; Monestiez, Pascal; Pettex, Emeline; Stephan, Eric; Van Canneyt, Olivier; Ridoux, Vincent

2017-07-01

From the Habitat Directive to the recent Marine Strategy Framework Directive, the conservation status of cetaceans in European water has been of concern for over two decades. In this study, a seasonal comparison of the abundance and distribution of cetaceans was carried out in two contrasted regions of the Eastern North Atlantic, the Bay of Biscay and the English Channel. Estimates were obtained in the two sub-regions (375,000 km²) from large aerial surveys conducted in the winter (November 2011 to February 2012) and in the summer (May to August 2012). The most abundant species encountered in the Channel, the harbour porpoise, displayed strong seasonal variations in its distribution but a stable abundance (18,000 individuals, CV=30%). In the Bay of Biscay, abundance and distribution patterns of common / striped dolphins varied from 285,000 individuals (95% CI: 174,000-481,000) in the winter, preferentially distributed close to the shelf break, to 494,000 individuals (95% CI: 342,000-719,000) distributed beyond the shelf break in summer. Baleen whales also exhibited an increase of their density in summer. Seasonal abundances of bottlenose dolphins were quite stable, with a large number of 'pelagic' encounters offshore in winter. No significant seasonal difference was estimated for pilot whales and sperm whale. These surveys provided baseline estimates to inform policies to be developed, or for existing conservation instruments such as the Habitats Directive. In addition, our results supported the hypothesis of a shift in the summer distributions of some species such as harbour porpoise and minke whale in European waters.

Relationships Between Individual Endorsement of Aggressive Behaviors and Thoughts With Prejudice Relevant Correlates Among Adolescents

PubMed Central

Piumatti, Giovanni; Mosso, Cristina

2017-01-01

The current study explored how individual differences in endorsement of aggressive behaviors and thoughts relate to individual levels of tolerance and prejudice toward immigrants and established prejudice correlates such as social dominance orientation (SDO) and ethnic out-groups ratings among adolescents. Participants (N = 141; Age M = 16.08, 68% girls) completed the Readiness for Interpersonal Aggression Inventory, the Tolerance and Prejudice Questionnaire, and measures of SDO and ethnic out-groups ratings. Results indicated that higher individual endorsement of aggression was related to higher prejudice and SDO and lower tolerance and ethnic out-groups ratings. Patterns of endorsement of aggression related to habitual and socially determined aggressive acts or stable needs to hurt others as a source of satisfaction were significantly correlated with prejudice. Conversely, the relationship between prejudice and endorsement of impulsive actions lacking of emotional control resulted was less marked. The results highlight how in the cognitive spectrum of prejudice, individual levels of endorsement of aggression may play a significant triggering role during adolescence. These findings may have implications for future studies and interventions aimed at reducing prejudice already in young ages. PMID:28344674