795 resultados para Risk-taking Behavior


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Starvation during early development can have lasting effects that influence organismal fitness and disease risk. We characterized the long-term phenotypic consequences of starvation during early larval development in Caenorhabditis elegans to determine potential fitness effects and develop it as a model for mechanistic studies. We varied the amount of time that larvae were developmentally arrested by starvation after hatching ("L1 arrest"). Worms recovering from extended starvation grew slowly, taking longer to become reproductive, and were smaller as adults. Fecundity was also reduced, with the smallest individuals most severely affected. Feeding behavior was impaired, possibly contributing to deficits in growth and reproduction. Previously starved larvae were more sensitive to subsequent starvation, suggesting decreased fitness even in poor conditions. We discovered that smaller larvae are more resistant to heat, but this correlation does not require passage through L1 arrest. The progeny of starved animals were also adversely affected: Embryo quality was diminished, incidence of males was increased, progeny were smaller, and their brood size was reduced. However, the progeny and grandprogeny of starved larvae were more resistant to starvation. In addition, the progeny, grandprogeny, and great-grandprogeny were more resistant to heat, suggesting epigenetic inheritance of acquired resistance to starvation and heat. Notably, such resistance was inherited exclusively from individuals most severely affected by starvation in the first generation, suggesting an evolutionary bet-hedging strategy. In summary, our results demonstrate that starvation affects a variety of life-history traits in the exposed animals and their descendants, some presumably reflecting fitness costs but others potentially adaptive.

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Design for manufacture of system-in-package (SiP) structures is dependent on a number of physical processes that affect the final quality of the package in terms of its performance and reliability. Solder joints are key structures in a SiP and their behavior can be the critical factor in terms of reliability. This paper discusses the results from a research programme on design for manufacturing of system in package (SiP) technologies. The focus of the paper is on thermo-mechanical modelling of solder joints. This includes the behavior of the joints during testing plus some important insights into the reflow process and how physical phenomena taking place at the assembly stage can affect solder joint behavior. Finite element analysis of a numerical model of an SiP structure with various design parameters is discussed. The goal of this analysis is to identify the most promising combination of design parameters which guarantee longer lifetime of the solder joints and hence the SiP component. The parameters that were studied are the size of the package (i.e. number of solder joints per row), the presence of the underfill and/or the reinforcement as well as the thickness of the passive die. Discussion was also provided on phenomena that take place during the reflow process where the solder joints are formed. In particular, the formation of intermetallics at the solder-pad interfaces

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Cooperatives have a long historical experience in the Spanish economy and have demonstrated their ability to compete against traditional firms in the market. To maintain this capability, while taking advantage of the competitive advantages associated with their idiosyncrasies as social economy enterprises, they should take into consideration that the economy is increasingly globalized and increasingly knowledge-based, especially with regards to technological content. As a consequence, the innovative capacity appears to be a key aspect in order to be able to challenge competitors. This article characterizes the innovative behavior of cooperatives in the region of Castile and Leon and analyses the internal and external factors affecting their innovative performance, based on data from a survey of 581 cooperatives. The results of the empirical analysis, which is performed by multivariate binary logistic regression on various types of innovation, lead us to identify the size of the organizations, the existence of planning, the R & D activities and the human capital as the main determining factors.

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Livestock face complex foraging options associated with optimizing nutrient intake while being able to avoid areas posing risk of parasites or disease. Areas of tall nutrient-rich swards around fecal deposits may be attractive for grazing, but might incur fitness costs from parasites. We use the example of dairy cattle and the risks of tuberculosis transmission posed to them by pastures contaminated with badger excreta to examine this trade-off. A risk may be posed either by aerosolized inhalation through investigation or by ingestion via grazing contaminated swards. We quantified the levels of investigation and grazing of 150 dairy cows at badger latrines (accumulations of feces and urine) and crossing points (urination-only sites). Grazing behavior was compared between strip-grazed and rotation-grazed fields. Strip grazing had fields subdivided for grazing periods of

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We examined the trade-off between the behaviours associated with predator avoidance and mate acquisition in the mate-guarding amphipod crustacean Gammarus duebeni. We used laboratory experiments to investigate the impact of olfactory predator cues on activity, mate choice and mate-guarding behaviour of males and females. Pair formation declined under perceived risk of predation, reflecting reduced activity of both males and females and hence a reduced likelihood of encountering a mate. We also observed a reduction in the choosiness of both males and females. Under increased perceived predation risk, assessment of the female by the male was more likely to be followed by pair formation, and males showed a nonsignificant trend towards reduced discrimination in favour of large females and were less tenacious in their pair bond when they paired during exposure to predator cues. Females also showed less resistance behaviour, suggesting that both males and females trade off the costs of maximizing current reproductive success against the benefits of predator avoidance for survival and reproduction in the future. We discuss the implications of such context-dependent mating behaviours for ecological interactions between species and suggest that predators, via the effects of perceived predation risk on mate choice and mate guarding in the prey species, induce trait-mediated indirect effects with the potential to influence population dynamics and community structure. (C) 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

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1.How much should an individual invest in reproduction as it grows older? Answering this question involves determining whether individuals measure their age as the time left for future reproduction or as the rate of deterioration in their state. Theory suggests that in the former case individuals should increase their allocation of resources to reproduction as opportunities for future breeding dwindle, and terminally invest when they breed for the last time. In the latter case they should reduce their investment in reproduction with age, either through adaptive reproductive restraint or as a passive by-product of senescence.
2.Here we present the results of experiments on female burying beetles, Nicrophorus vespilloides, in which we independently manipulated the perceived risk of death (by activating the immune system) and the extent of deterioration in state (by changing age of first reproduction and/or prior investment in reproduction).
3.We found that the risk of death and state each independently influenced the extent of reproductive investment. Specifically, we found a state-dependent decline in reproductive investment as females grew older that could be attributed to both adaptive reproductive restraint and senescence. A perceived increase in the risk of death, induced by activation of the immune system, caused females to switch from a strategy of reproductive restraint to terminal investment. Nevertheless, absolute reproductive investment was lower in older females, indicating constraints of senescence.
4.Our results show that a decline in reproductive investment with age does not necessarily constitute evidence of reproductive senescence but can also result from adaptive reproductive restraint.
5.Our results further suggest that the extent of reproductive investment is dependent on several different intrinsic cues and that the particular blend of cues available at any given age can yield very different patterns of investment. Perhaps this explains why age-related reproductive investment patterns seen in nature are so diverse.

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Sex differences in schizophrenia are well known, but their genetic basis has not been identified. We performed a genome-wide association scan for schizophrenia in an Ashkenazi Jewish population using DNA pooling. We found a female-specific association with rs7341475, a SNP in the fourth intron of the reelin ( RELN) gene (p = 2.9 x 10(-5) in women), with a significant gene-sex effect (p = 1.8 x 10(-4)). We studied rs7341475 in four additional populations, totaling 2,274 cases and 4,401 controls. A significant effect was observed only in women, replicating the initial result (p = 2.1 x 10(-3) in women; p = 4.2 x 10(-3) for gene-sex interaction). Based on all populations the estimated relative risk of women carrying the common genotype is 1.58 (p = 8.8 x 10(-7); p = 1.6 x 10(-5) for gene-sex interaction). The female-specific association between RELN and schizophrenia is one of the few examples of a replicated sex-specific genetic association in any disease.

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Background: Previous studies have not demonstrated a consistent association between potentially inappropriate medicines (PIMs) in older patients as defined by Beers criteria and avoidable adverse drug events (ADEs). This study aimed to assess whether PIMs defined by new STOPP (Screening Tool of Older Persons’ potentially inappropriate Prescriptions) criteria are significantly associated with ADEs in older people with acute illness.

Methods: We prospectively studied 600 consecutive patients 65 years or older who were admitted with acute illness to a university teaching hospital over a 4-month interval. Potentially inappropriate medicines were defined by both Beers and STOPP criteria. Adverse drug events were defined by World Health Organization–Uppsala Monitoring Centre criteria and verified by a local expert consensus panel, which also assessed whether ADEs were causal or contributory to current hospitalization. Hallas criteria defined ADE avoidability.Wecompared the proportions of patients taking Beers criteria PIMs
and STOPP criteria PIMs with avoidable ADEs that were causal or contributory to admission.

Results: A total of 329 ADEs were detected in 158 of 600 patients (26.3%); 219 of 329 ADEs (66.6%) were considered causal or contributory to admission. Of the 219 ADEs, 151(68.9%)considered causal or contributory to admission were avoidable or potentially avoidable. After adjusting for age, sex, comorbidity, dementia, baseline activities of daily living function, and number of medications, the likelihood of a serious avoidable ADE increased significantly when STOPP PIMs were prescribed (odds ratio, 1.847; 95% confidence interval [CI], 1.506-2.264; P.001); prescription of Beers criteria PIMs did not significantly increase ADE risk (odds ratio, 1.276; 95% CI, 0.945-1.722; P=.11).

Conclusion: STOPP criteria PIMs,unlike Beers criteria PIMs, are significantly associated with avoidable ADEs in older people that cause or contribute to urgent hospitalization.

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This study examined the role of prolonged, repeated traumatic experiences such as childhood and sectarian trauma in the development of posttraumatic aggression and self-harm. Forty-four adult participants attending therapy for complex trauma in Northern Ireland were obtained via convenience sampling. When social desirability was controlled, childhood emotional and physical neglect were significant correlates of posttraumatic hostility and history of self-harm. These relationships were mediated by alterations in self-perception (e.g., shame, guilt). Severity of sectarian-related experiences was not related to self-destructive behaviors. Moreover, none of the trauma factors were related to overt aggressive behavior. The findings have implications for understanding risk factors for posttraumatic aggression and self-harm, as well as their treatment. © 2013 Copyright Taylor & Francis Group, LLC.

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Background Previous research has shown that home ownership is associated with a reduced risk of admission to institutional care. The extent to which this reflects associations between wealth and health, between wealth and ability to buy in care or increased motivation to avoid admission related to policies on charging is unclear. Taking account of the value of the home, as well as housing tenure, may provide some clarification as to the relative importance of these factors.
Aims To analyse the probability of admission to residential and nursing home care according to housing tenure and house value.
Methods Cox regression was used to examine the association between home ownership, house value and risk of care home admissions over 6 years of follow-up among a cohort of 51 619 people aged 65 years or older drawn from the Northern Ireland Longitudinal Study, a representative sample of approximate to 28% of the population of Northern Ireland.
Results 4% of the cohort (2138) was admitted during follow-up. Homeowners were less likely than those who rented to be admitted to care homes (HR 0.77, 95% CI 0.70 to 0.85, after adjusting for age, sex, health, living arrangement and urban/rural differences). There was a strong association between house value/tenure and health with those in the highest valued houses having the lowest odds of less than good health or limiting long-term illness. However, there was no difference in probability of admission according to house value; HRs of 0.78 (95% CI 0.67 to 0.90) and 0.81 (95% CI 0.70 to 0.95), respectively, for the lowest and highest value houses compared with renters.
Conclusions The requirement for people in the UK with capital resources to contribute to their care is a significant disincentive to institutional admission. This may place an additional burden on carers.

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Prostate cancer is the most commonly diagnosed cancer in men. Evidence suggests that smokers may be at increased risk of prostate cancer compared to non-smokers. In the present study we ask whether adult men who smoke are also less likely to undergo screening for prostate cancer. Adult men aged 46 and above completed a single questionnaire including demographic items and items concerning their smoking status and previous testing for prostate cancer. The questionnaire also included an 11 item numeracy scale. Compared to smokers, non-smokers and ex-smokers were around two times more likely to have undergone screening for prostate cancer, and had been tested more frequently. Smokers are not only more likely to develop prostate cancer, they are, paradoxically, less likely to undergo screening for prostate cancer. Health care professionals need to be cognizant of individual differences in screening behavior and that smokers have a reduced likelihood of choosing to screen. © 2012 Elsevier Ltd.

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To investigate whether prenatal selective serotonin reuptake inhibitor (SSRI) antidepressant exposure affects behavior in 3-year-olds of antenatally anxious or depressed mothers and whether risk was moderated by the serotonin transporter promoter (SLC6A4) genotype.

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There is evidence that the developmental trajectory of cortisol secretion in preterm infants is altered, with elevated basal cortisol levels observed postnatally through at least 18 months corrected age (CA). This alteration is possibly due to neonatal pain-related stress. High cortisol levels might contribute to greater risk of impaired neurodevelopment. Since maternal factors are important for the regulation of infant stress responses, we investigated relationships between infant (neonatal pain-related stress, attention, cortisol) and maternal (stress, interactive behaviors) factors at age 8 months CA. We found that interactive maternal behaviors buffered the relationship between high neonatal pain-related stress exposure and poorer focused attention in mothers who self-reported low concurrent stress. Furthermore, in preterm infants exposed to high concurrent maternal stress and overwhelming interactive maternal behaviors, higher basal cortisol levels were associated with poor focused attention. Overall, these findings suggest that maternal factors can influence the cognitive resilience at 8 months of preterm infants exposed to early life stress.