164 resultados para biological traits


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The evolution of grasses using C4 photosynthesis and their sudden rise to ecological dominance 3 to 8 million years ago is among the most dramatic examples of biome assembly in the geological record. A growing body of work suggests that the patterns and drivers of C4 grassland expansion were considerably more complex than originally assumed. Previous research has benefited substantially from dialog between geologists and ecologists, but current research must now integrate fully with phylogenetics. A synthesis of grass evolutionary biology with grassland ecosystem science will further our knowledge of the evolution of traits that promote dominance in grassland systems and will provide a new context in which to evaluate the relative importance of C4 photosynthesis in transforming ecosystems across large regions of Earth.

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Research suggests that implicit attitudes play a key role in the occurrence of antisocial behaviours. This study assessed implicit attitudes and self-concepts related to aggression and transgression in community and offender adolescents, using a new set of Implicit Association Tests (IATs), and examined their association with of psychopathic traits. Thirty-six offenders and 66 community adolescents performed 4 IATs assessing 1) implicit attitudes about a) aggression and b) transgression as good, and 2) implicit self-concepts about a) aggression and b) transgression as self-descriptive. They filled in self-report questionnaires: the Youth Psychopathic Traits Inventory, the Child Behaviour Checklist, and explicit measures of their attitudes and self-concepts towards transgression and aggression. Results showed few differences between community and offender adolescents on implicit attitudes and self-concepts, and unexpected negative associations between some implicit attitudes and psychopathic traits, while the association was positive for the corresponding explicit attitudes. Possible explanations of these findings are discussed.

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Trait decay may occur when selective pressures shift, owing to changes in environment or life style, rendering formerly adaptive traits non-functional or even maladaptive. It remains largely unknown if such decay would stem from multiple mutations with small effects or rather involve few loci with major phenotypic effects. Here, we investigate the decay of female sexual traits, and the genetic causes thereof, in a transition from haplodiploid sexual reproduction to endosymbiont-induced asexual reproduction in the parasitoid wasp Asobara japonica. We take advantage of the fact that asexual females cured of their endosymbionts produce sons instead of daughters, and that these sons can be crossed with sexual females. By combining behavioral experiments with crosses designed to introgress alleles from the asexual into the sexual genome, we found that sexual attractiveness, mating, egg fertilization and plastic adjustment of offspring sex ratio (in response to variation in local mate competition) are decayed in asexual A. japonica females. Furthermore, introgression experiments revealed that the propensity for cured asexual females to produce only sons (because of decayed sexual attractiveness, mating behavior and/or egg fertilization) is likely caused by recessive genetic effects at a single locus. Recessive effects were also found to cause decay of plastic sex-ratio adjustment under variable levels of local mate competition. Our results suggest that few recessive mutations drive decay of female sexual traits, at least in asexual species deriving from haplodiploid sexual ancestors.

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BACKGROUND AND AIMS: Both personality changes and behavioural and psychological symptoms (BPS) may be associated with mild cognitive impairment (MCI) in later life and help identify incipient dementia. We wished to investigate the links between personality and BPS in MCI. METHOD: We studied premorbid personality traits as estimated 5 years back and their changes in 83 control subjects and 52 MCI patients using the revised NEO Personality Inventory for the Five-Factor Model completed by a proxy. Information on BPS was obtained using the Neuropsychiatric Inventory (NPI). Analyses were controlled for current depression and anxiety. RESULTS: Premorbid neuroticism and openness to experience were associated with the total NPI score. The changes in neuroticism, extraversion, openness to experiences, and conscientiousness were associated with apathy and affective symptoms. CONCLUSIONS: Personality changes and BPS occur in MCI. The occurrence of affective BPS and apathy is associated with both premorbid personality traits and their changes.

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OBJECTIVE: The origins of behavioral and psychological symptoms (BPS) in Alzheimer's disease (AD) are still poorly understood. Focusing on individual personality structure, we explored the relationship between premorbid personality and its changes over 5 years, and BPS in patients at an early stage of AD. METHOD: A total of 54 patients at an early stage of AD according to ICD-10 and NINCDS-ADRDA criteria and 64 control subjects were included. Family members filled in the Neuropsychiatric Inventory Questionnaire to evaluate their proxies' current BPS and the NEO Personality Inventory Revised twice, the first time to evaluate the participants' current personality and the second time to assess personality traits as they were remembered to be 5 years earlier. RESULTS: Behavioral and psychological symptoms, in particular apathy, depression, anxiety, and agitation, are frequent occurrences in early stage AD. Premorbid personality differed between AD patients and normal control, but it was not predictive of BPS in patients with AD. Personality traits clearly change in the course of beginning AD, and this change seems to develop in parallel with BPS as early signs of AD. CONCLUSIONS: Premorbid personality was not associated with BPS in early stage of AD, although complex and non-linear relationships between the two are not excluded. However, both personality and behavioral changes occur early in the course of AD, and recognizing them as possible, early warning signs of neurodegeneration may prove to be a key factor for early detection and intervention. Copyright © 2012 John Wiley & Sons, Ltd.

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Since 1990, several techniques have been developed to photochemically inactivate pathogens in platelet concentrates, potentially leading to safer transfusion therapy. The three most common methods are amotosalen/UVA (INTERCEPT Blood System), riboflavin/UVA-UVB (MIRASOL PRT), and UVC (Theraflex-UV). We review the biology of pathogen inactivation methods, present their efficacy in reducing pathogens, discuss their impact on the functional aspects of treated platelets, and review clinical studies showing the clinical efficiency of the pathogen inactivation methods and their possible toxicity.

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AIM: In normal aging, subjective cognitive decline (SCD) might reflect personality traits or affective states rather than objective cognitive decline. However, little is known on the correlates of SCD in mild cognitive impairment (MCI). The present study investigates SCD in MCI patients and healthy older adults, and explores the association of SCD with personality traits, affective states, behavioral and psychological symptoms (BPS), and episodic memory in patients with MCI as compared with healthy older adults. METHODS: A total of 55 patients with MCI and 84 healthy older adults were recruited. Standard instruments were used to evaluate SCD, episodic memory, BPS and affective states. Premorbid and current personality traits were assessed by proxies using the NEO Personality Inventory Revised. RESULTS: Patients with MCI generally reported SCD more often than healthy older adults. SCD was positively associated with depressive symptoms in both groups. With regard to personality, no significant relationship was found in the healthy older group, whereas agreeableness was significantly negatively related to SCD in the MCI group. No significant association was found between SCD and episodic memory. CONCLUSIONS: SCD is more prevalent in patients with MCI than in the healthy elderly, but it does not reflect an objective cognitive impairment. SCD rather echoes depressive symptoms in both patients with MCI and healthy subjects. The negative association of SCD with agreeableness observed in patients with MCI could indicate that MCI patients scoring high on the agreeableness trait would not report SCD in order to prevent their relatives worrying about their increasing cognitive difficulties.

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The ability to identify the species origin of an unknown biological sample is relevant in the fields of human and wildlife forensics. However, the detection of several species mixed in the same sample still remains a challenge. We developed and tested a new approach for mammal DNA identification in mixtures of two or three species, based on the analysis of mitochondrial DNA control region interspecific length polymorphism followed by direct sequencing. Contrary to other published methods dealing with species mixtures, our protocol requires a single universal primer pair and is not based on a pre-defined panel of species. Amplicons can be separated either on agarose gels or using CE. The advantages and limitations of the assay are discussed under different conditions, such as variable template concentration, amplicon sizes and size difference among the amplicons present in the mixture. For the first time, this protocol provides a simple, reliable and flexible method for simultaneous identification of multiple mammalian species from mixtures, without any prior knowledge of the species involved.

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BACKGROUND: The FIFA has implemented an important antidoping programme for the 2014 FIFA World Cup. AIM: To perform the analyses before and during the World Cup with biological monitoring of blood and urine samples. METHODS: All qualified players from the 32 teams participating in the World Cup were tested out-of-competition. During the World Cup, 2-8 players per match were tested. Over 1000 samples were collected in total and analysed in the WADA accredited Laboratory of Lausanne. RESULTS: The quality of the analyses was at the required level as described in the WADA technical documents. The urinary steroid profiles of the players were stable and consistent with previously published papers on football players. During the competition, amphetamine was detected in a sample collected on a player who had a therapeutic use exemption for attention deficit hyperactivity disorder. The blood passport data showed no significant difference in haemoglobin values between out-of-competition and postmatch samples. CONCLUSIONS: Logistical issues linked to biological samples collection, and the overseas shipment during the World Cup did not impair the quality of the analyses, especially when used as the biological passport of football players.

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BACKGROUND/AIMS: Prospective studies on factors associated with adverse kidney outcomes in European general populations are scant. Also, few studies consider the potential confounding effect of baseline kidney function. METHODS: We used baseline (2003-2006) and 5-year follow-up data of adults from the general population to evaluate the effect of baseline kidney function and proteinuria on the association of clinical, biological (e.g. uric acid, homocysteine, cytokines), and socioeconomic factors with change in kidney function, rapid decline in kidney function, and incidence of chronic kidney disease (CKD). Estimated glomerular filtration rate (eGFR) and urinary albuminuria-to-creatinine ratio (UACR) were collected. Kidney outcomes were modeled using multivariable regressions. RESULTS: A total of 4,441 subjects were included in the analysis. Among participants without CKD at baseline, 11.4% presented rapid decline in eGFR and/or incident CKD. After adjustment for baseline eGFR and log UACR, only age (Odds Ratio; 1.25 [95%CI 1.18-1.33]), diabetes (OR 1.48 [1.03-2.13]), education (OR middle vs. high 1.51 [1.08-2.11]) and log ultrasensitive CRP (OR 1.16 [1.05-1.22]) were associated with rapid decline in eGFR or incident CKD. Baseline log UACR (OR 1.18 [1.06-1.32]) but not eGFR was associated with rapid decline in eGFR and/or incident CKD. CONCLUSION: In addition to age and diabetes, education and CRP levels are associated with adverse kidney outcomes independently of baseline kidney function.

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Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms.

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The Athlete Biological Passport (ABP) is an individual electronic document that collects data regarding a specific athlete that is useful in differentiating between natural physiologic variations of selected biomarkers and deviations caused by artificial manipulations. A subsidiary of the endocrine module of the ABP, that which here is called Athlete Steroidal Passport (ASP), collects data on markers of an altered metabolism of endogenous steroidal hormones measured in urine samples. The ASP aims to identify not only doping with anabolic-androgenic steroids, but also most indirect steroid doping strategies such as doping with estrogen receptor antagonists and aromatase inhibitors. Development of specific markers of steroid doping, use of the athlete's previous measurements to define individual limits, with the athlete becoming his or her own reference, the inclusion of heterogeneous factors such as the UDPglucuronosyltransferase B17 genotype of the athlete, the knowledge of potentially confounding effects such as heavy alcohol consumption, the development of an external quality control system to control analytical uncertainty, and finally the use of Bayesian inferential methods to evaluate the value of indirect evidence have made the ASP a valuable alternative to deter steroid doping in elite sports. The ASP can be used to target athletes for gas chromatography/combustion/ isotope ratio mass spectrometry (GC/C/IRMS) testing, to withdraw temporarily the athlete from competing when an abnormality has been detected, and ultimately to lead to an antidoping infraction if that abnormality cannot be explained by a medical condition. Although the ASP has been developed primarily to ensure fairness in elite sports, its application in endocrinology for clinical purposes is straightforward in an evidence-based medicine paradigm.

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The study of culturally inherited traits has led to the suggestion that the evolution of helping behaviors is more likely with cultural transmission than without. Here we evaluate this idea through a comparative analysis of selection on helping under both genetic and cultural inheritance. We develop two simple models for the evolution of helping through cultural group selection: one in which selection on the trait depends solely on Darwinian fitness effects and one in which selection is driven by nonreproductive factors, specifically imitation of strategies achieving higher payoffs. We show that when cultural variants affect Darwinian fitness, the selection pressure on helping can be markedly increased relative to that under genetic transmission. By contrast, when variants are driven by nonreproductive factors, the selection pressure on helping may be reduced relative to that under genetic inheritance. This occurs because, unlike biological offspring, the spread of cultural variants from one group to another through imitation does not reduce the number of these variants in the source group. As a consequence, there is increased within-group competition associated with traits increasing group productivity, which reduces the benefits of helping. In these cases, selection for harming behavior (decreasing the payoff to neighbors) may occur rather than selection for helping.

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Four West Malaysian shrew populations of the genus Crocidura were investigated through their karyotype and allozyme variations, and, in part, by interfertility experiments. Two different karyotypes characterize these shrews. The first, restricted to the Cameron Highlands (Peninsular Malaysia), invariably has 2n = 40 chromosomes but a varying fundamental number (FN = 54-58). The second karyotype shows a fundamental number of 62-68 and a polymorphic chromosomal number of 2n = 38, 39 or 40, a rare event in the genus Crocidura. Thus both can be distinguished by either a low or a higher number of meta- and submetacentric elements. In heterospecific breeding experiments, mutual avoidance was observed suggesting prezygotic barriers, whereas intraspecific pairs produced 13 liters (mean 2.1 young). Furthermore, our biochemical results indicate that both karyotypes correspond to a relatively ancient separation (Nei's D = 0.354), an amount of genetic differentiation comparable to the distance separating them from the West Palearctic C. russula (D = 0.429-0.583). In contrast, conspecific island and mainland Malaysian shrews possessing the second karyotype had only one fixed allelic difference over the 35 loci surveyed. The problem of naming the two biological species remains unsolved and requires further comparative investigations.

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Several recent studies have explored various aspects of animal personality and their ecological consequences. However, the processes responsible for the maintenance of personality variability within a population are still largely unknown. We have recently demonstrated that social personality traits exist in the common lizard (Lacerta vivipara) and that the variation in sociability provides an explanation for variable dispersal responses within a given species. However, we need to know the fitness consequences of variation in sociability across environmental contexts in order to better understand the maintenance of such variation. In order to achieve this, we investigated the relationship between sociability and survival, body growth and fecundity, in one-year-old individuals in semi-natural populations with varying density. 'Asocial' and 'social' lizards displayed different fitness outcomes in populations of different densities. Asocial lizards survived better in low-density populations, while social females reproduced better. Spatiotemporal variation in environmental conditions might thus be the process underlying the maintenance of these personality traits within a population. Finally, we also discuss the position of sociability in a more general individual behavioural pattern including boldness, exploration and aggressiveness.