38 resultados para Self-directed behavior

em Université de Lausanne, Switzerland


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Acquired behavioral changes have essentially been described in advanced multiple sclerosis (MS). The present study was designed to determine whether behavioral modifications specifically related to the MS pathological process could be identified in the initial phase of the disease, as compared to control patients with chronic, relapsing and progressive inflammatory disorders not involving the central nervous system (CNS). Eighty-eight early MS patients (Expanded Disability Status Scale score <or= 2.5) and 48 controls were tested. Perceived changes by informants in behavioral control, goal-directed behavior, decision making, emotional expression, insight and interpersonal relationships were assessed using the Iowa Scale of Personality Change (ISPC). Executive behavioral disturbances were screened using the Dysexecutive Questionnaire (DEX). The mean change between the premorbid and postmorbid ISPC ratings was similar in the MS [12.2 (SD 15.6)] and in the control [11.5 (SD 15.1)] group. The perceived behavioral changes (PBCs) most frequently reported in both groups were lack of stamina, lability/moodiness, anxiety, vulnerability to stress and irritability. Pathological scores in the DEX were also similar in both groups. Correlations between PBCs and DEX scores were different in MS and control groups. MS patients with cognitive impairment had a marginally higher number of PBCs than control patients (p=0.056) and a significantly higher DEXp score (p=0.04). These results suggest that (1) PBCs occurring in early MS patients were not different from those induced by comparable chronic non-CNS disorders, (2) qualitative differences in the relationship between behavioral symptoms and executive-behavioral changes may exist between MS and control groups, and (3) behavioral symptoms seem associated with cognitive deficits in MS. We further plan to assess these observations longitudinally.

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It has recently been proposed that the SSAT gene plays a role in the predisposition to suicidal behavior. SSAT expression was found to be down-regulated in the brain of suicide completers. In addition, a single nucleotide polymorphism (SNP) rs6526342 was associated both with variation in SSAT expression and with suicidal behavior. In this study, we aimed to characterize the relationship between SSAT dysregulation and suicide behavior. To this end, we measured SSAT expression levels in the ventral prefrontal cortex (VPFC) of suicide completers (n = 20) and controls (n = 20) and found them to be significantly down-regulated in suicide victims (P = 0.007). To identify the basis of the regulation of SSAT expression, we performed an association analysis of 309 SNPs with SSAT transcript levels in 53 lymphoblastoid cell lines from the CEPH collection. We then examined the methylation status of the SSAT promoter region in males and females suicide completers and control subjects whose SSAT brain expression had been measured. We found no evidence to support a role for SNPs in controlling the level of SSAT expression. SSAT promoter methylation levels were not different between suicide completers and controls and did not correlate with SSAT expression levels. In addition, we found no indication of a genetic association between suicidal behavior and SNPs located within the SSAT gene. Our study provides new results which show that dysregulation of SSAT expression does play a role in suicide behavior. However, our data do not support any association between rs6526342 and variation in SSAT expression or suicidal behavior.

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In this paper, I reframe the long-standing controversy between 'psychological egoism', which argues that human beings never perform altruistic actions, and the opposing thesis of 'psychological altruism', which claims that human beings are, at least sometimes, capable of acting in an altruistic fashion. After a brief sketch of the controversy, I begin by presenting some representative arguments in favour of psychological altruism before showing that they can all be called into question by appealing to the idea of an unconscious self-directed motive. I will then point out that this argumentative strategy not only debunks the reasons for favouring psychological altruism, but also those for favouring psychological egoism; hence it is no use in settling the dispute between the two views. In the second part of the paper, I will try to break this deadlock by reframing the whole controversy, shifting it away from the concept of motive, towards the broader notion of motivation. As it turns out, this shift enables the debate to centre on altruistic emotions and their motivational power, thereby allowing evolutionary arguments to enter the debate and settle the dispute in favour of psychological altruism.

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Summary Aims.-To explore whether fatigue-induced changes in spring-mass behavior during a 5000m self-paced run varied according to the runner's training status. Methods and results.-Six highly- and six well-trained triathletes completed a 5000m time trial. Running velocity and vertical stiffness decreased significantly (P < 0.05) with fatigue, whereas leg stiffness remained constant. None of these parameters displayed a significant interaction between fatigue and training status, despite vertical stiffness being higher (P < 0.05) in highly-trained triathletes. Conclusions.-During a 5000m self-paced run, impairments in leg-spring behavior that occur with fatigue are not affected by athletes' training status. © 2009 Elsevier Masson SAS. All rights reserved. Objectifs.-Étudier, chez des athlètes de niveaux différents, les modifications de raideur mécanique liées à l'apparition de la fatigue lors d'une course de 5000 m. Synthèse des faits.-Six triathlètes très entraînés et six autres bien entraînés ont réalisé une course de 5000 m. La vitesse de course et la raideur verticale diminuaient significativement (p < 0,05) avec la fatigue, alors que la raideur de la jambe demeurait inchangée. Aucune interaction entre la fatigue et le niveau d'entraînement n'a été détectée, malgré des niveaux de raideur verticale plus élevés (p < 0,05) chez les sujets les mieux entraînés.

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Trade-offs between the benefits of current reproduction and the costs to future reproduction and survival are widely recognized. However, such trade-offs might only be detected when resources become limited to the point where investment in one activity jeopardizes investment in others. The resolution of the trade-off between reproduction and self-maintenance is mediated by hormones such as glucocorticoids which direct behaviour and physiology towards self-maintenance under stressful situations. We investigated this trade-off in male and female barn owls in relation to the degree of heritable melanin-based coloration, a trait that reflects the ability to cope with various sources of stress in nestlings. We increased circulating corticosterone in breeding adults by implanting a corticosterone-releasing-pellet, using birds implanted with a placebo-pellet as controls. In males, elevated corticosterone reduced the activity (i.e. reduced home-range size and distance covered within the home-range) independently of coloration, while we could not detect any effect on hunting efficiency. The effect of experimentally elevated corticosterone on female behaviour was correlated with their melanin-based coloration. Corticosterone (cort-) induced an increase in brooding behaviour in small-spotted females, while this hormone had no detectable effect in large-spotted females. Cort-females with small eumelanic spots showed the normal body-mass loss during the early nestling period, while large spotted cort-females did not lose body mass. This indicates that corticosterone induced a shift towards self-maintenance in males independently on their plumage, whereas in females this shift was observed only in large-spotted females.

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This study on determinants of sexual protection behavior among HIV-positive gay men used the empirically tested information-motivation-behavioral skills (IMB) model. HIV-specific variables were added to the model to determine factors decisive for condom use with steady and casual partners. Data were collected using an anonymous, standardized self-administered questionnaire. Study participants were recruited at HIV outpatient clinics associated with the Eurosupport Study Group and the Swiss HIV Cohort Study. To identify factors associated with condom use, backward elimination regression analyses were performed. Overall, 838 HIV-infected gay men from 14 European countries were included in this analysis. About 53% of them reported at least one sexual contact with a steady partner; 62.5% had sex with a casual partner during the last 6 months. Forty-three percent always used condoms with steady partners and 44% with casual partners. High self-efficacy and subjective norms in favor of condom-use were associated with increased condom use with casual and steady partners, whereas feeling depressed was associated with decreased condom use with casual partners. Condoms were used less often with HIV-positive partners. Self-efficacy as an important behavioral skill to perform protection behavior was influenced by lower perceived vulnerability, higher subjective norms, and more positive safer sex attitudes. The IMB-model constructs appeared to be valid; however, not all the model predictors could be determined as hypothesized. Besides the original IMB constructs, HIV-specific variables, including sexual partners' serostatus and mental health, explained condom use. Such factors should be considered in clinical interventions to promote "positive prevention."

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Purpose: to assess the trends of self-reported prevalence of cardiovascular risk factors (CV RFs: hypertension, dyslipidaemia, diabetes) and their management for period 1992 to 2007 in the Swiss population. Methods: four National health interview surveys conducted between 1992 and 2007 in representative samples of the Swiss population (63,782 subjects overall). Self-reported CV RFs prevalence, treatment and controllevels were computed after weighting. Weights were calculated by raking ratio such that the marginal distribution of the weighted totals conforms to the marginal distribution of the targeted population. Multivariate analysis adjusted on age, sex, education, nationality and SMI was conducted using logistic regression. Results: prevalence of ail CV RFs increased between 1992 and 2007, see table. Although the self-reported prevalence of treatment among subjects with CV RFs increased, and this was confirmed by multivariate analysis: OR for hypocholesterolaemic treatment relative to 1992: 0.64 [0.52-0.78]; 1.39 [1.18-1.65] and 2.00 [1.69-2.36] for 1997, 2002 and 2007, respectively. Still, in 2007, circa 40% of hypertensive, 60% of dyslipidaemic and 50% of diabetic subjects weren't treated. Conversely, an adequate control of CV RFs was reported by treated subjects, with an increase during the study period. This increase was confirmed by multivariate analysis (not shown). Conclusion: the self-reported prevalence of hypertension, dyslipidaemia and diabetes increased between 1992 and 2007 in the Swiss population. Despite a good control of treated subjects, still a significant percentage of subjects with CV RFs are not treated.

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MOTIVATION: Regulatory gene networks contain generic modules such as feedback loops that are essential for the regulation of many biological functions. The study of the stochastic mechanisms of gene regulation is instrumental for the understanding of how cells maintain their expression at levels commensurate with their biological role, as well as to engineer gene expression switches of appropriate behavior. The lack of precise knowledge on the steady-state distribution of gene expression requires the use of Gillespie algorithms and Monte-Carlo approximations. METHODOLOGY: In this study, we provide new exact formulas and efficient numerical algorithms for computing/modeling the steady-state of a class of self-regulated genes, and we use it to model/compute the stochastic expression of a gene of interest in an engineered network introduced in mammalian cells. The behavior of the genetic network is then analyzed experimentally in living cells. RESULTS: Stochastic models often reveal counter-intuitive experimental behaviors, and we find that this genetic architecture displays a unimodal behavior in mammalian cells, which was unexpected given its known bimodal response in unicellular organisms. We provide a molecular rationale for this behavior, and we implement it in the mathematical picture to explain the experimental results obtained from this network.

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Epidemiological data indicate that 75% of subjects with major psychiatric disorders have their onset in the age range of 17-24 years. An estimated 35-50% of college and university students drop out prematurely due to insufficient coping skills under chronic stress, while 85% of students receiving a psychiatric diagnosis withdraw from college/university prior to the completion of their education. In this study we aimed at developing standardized means for identifying students with insufficient coping skills under chronic stress and at risk for mental health problems. A sample of 1,217 college students from 3 different sites in the U.S. and Switzerland completed 2 self-report questionnaires: the Coping Strategies Inventory "COPE" and the Zurich Health Questionnaire "ZHQ" which assesses "regular exercises", "consumption behavior", "impaired physical health", "psychosomatic disturbances", and "impaired mental health". The data were subjected to structure analyses by means of a Neural Network approach. We found 2 highly stable and reproducible COPE scales that explained the observed inter-individual variation in coping behavior sufficiently well and in a socio-culturally independent way. The scales reflected basic coping behavior in terms of "activity-passivity" and "defeatism-resilience", and in the sense of stable, socio-culturally independent personality traits. Correlation analyses carried out for external validation revealed a close relationship between high scores on the defeatism scale and impaired physical and mental health. This underlined the role of insufficient coping behavior as a risk factor for physical and mental health problems. The combined COPE and ZHQ instruments appear to constitute powerful screening tools for insufficient coping skills under chronic stress and for risks of mental health problems.

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BACKGROUND: We examined body image perception and its association with reported weight-control behavior among adolescents in the Seychelles.METHODS: We conducted a school-based survey of 1432 students aging 11-17 years in the Seychelles. Perception of body image was assessed using both a closed-ended question (CEQ) and Stunkard's pictorial silhouettes (SPS). Voluntary attempts to change weight were also assessed.RESULTS: A substantial proportion of the overweight students did not consider themselves as overweight (SPS: 24%, CEQ: 34%), and a substantial proportion of the normal-weight students considered themselves as too thin (SPS: 29%, CEQ: 15%). Logistic regression analysis showed that students with an accurate weight perception were more likely to have appropriate weight-control behavior.CONCLUSIONS: We found that substantial proportions of students had an inaccurate perception of their weight and that weight perception was associated with weight-control behavior. These findings point to forces that can drive the upwards overweight trends.

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BACKGROUND: The second Swiss Multicenter Adolescent Survey on Health (SMASH02) was conducted among a representative sample (n = 7428) of students and apprentices aged 16 to 20 from the three language areas of Switzerland during the year 2002. This paper reports on health needs expressed by adolescents and their use of health care services over the 12 months preceding the survey. METHODS: Nineteen cantons representing 80% of the resident population agreed to participate. A complex iterative random cluster sample of 600 classes was drawn with classes as primary sampling unit. The participation rate was 97.7% for the classes and 99.8% for the youths in attendance. The self-administered questionnaire included 565 items. The median rate of item non-response was 1.8%. Ethical and legal requirements applying to surveys of adolescent populations were respected. RESULTS: Overall more than 90% of adolescents felt in good to excellent health. Suffering often or very often from different physical complaints or pain was also reported such as headache (boys: 15.9%, girls: 37.4%), stomach-ache (boys: 9.7%, girls: 30.0%), joint pain (boys: 24.7%, girls: 29.5%) or back pain (boys: 24.3%, girls: 34.7%). Many adolescents reported a need for help on psychosocial and lifestyle issues, such as stress (boys: 28.5%, girls: 47.7%) or depression (boys: 18.9%, girls: 34.4%). Although about 75% of adolescents reported having consulted a general practitioner and about one-third having seen another specialist, reported reasons for visits do not correspond to the expressed needs. Less than 10% of adolescents had visited a psychiatrist, a family planning centre or a social worker. CONCLUSIONS: The reported rates of health services utilisation by adolescents does not match the substantial reported needs for help in various areas. This may indicate that the corresponding problems are not adequately detected and/or addressed by professionals from the health and social sectors.