254 research outputs found

    High developmental temperature leads to low reproduction despite adult temperature

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    Phenotypic plasticity can help organisms cope with changing thermal conditions and it may depend on which life-stage the thermal stress is imposed: for instance, exposure to stressful temperatures during development can trigger a positive plastic response in adults. Here, we analyze the thermal plastic response of laboratory populations of Drosophila subobscura, derived from two contrasting latitudes of the European cline. We measured reproductive performance through fecundity characters, after the experimental populations were exposed to five thermal treatments, with different combinations of developmental and adult temperatures (14°C, 18°C, or 26°C). Our questions were whether (1) adult performance is changed with exposure to higher (or lower) temperatures during development; (2) flies raised at lower temperatures outperform those developed at higher ones, supporting the “colder is better” hypothesis; (3) there is a cumulative effect on adult performance of exposing both juveniles and adults to higher (or lower) temperatures; (4) there is evidence for biogeographical effects on adult performance. Our main findings were that (1) higher developmental temperatures led to low reproductive performance regardless of adult temperature, while at lower temperatures reduced performance only occurred when colder conditions were persistent across juvenile and adult stages; (2) flies raised at lower temperatures did not always outperform those developed at other temperatures; (3) there were no harmful cumulative effects after exposing both juveniles and adults to higher temperatures; (4) both latitudinal populations showed similar thermal plasticity patterns. The negative effect of high developmental temperature on reproductive performance, regardless of adult temperature, highlights the developmental stage as very critical and most vulnerable to climate change and associated heat waves.info:eu-repo/semantics/publishedVersio

    Beneficial developmental acclimation in reproductive performance under cold but not heat stress

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    Thermal plasticity can help organisms coping with climate change. In this study, we analyse how laboratory populations of the ectotherm species Drosophila subobscura, originally from two distinct latitudes and evolving for several generations in a stable thermal environment (18 °C), respond plastically to new thermal challenges. We measured adult performance (fecundity traits as a fitness proxy) of the experimental populations when exposed to five thermal regimes, three with the same temperature during development and adulthood (15-15 °C, 18-18 °C, 25-25 °C), and two where flies developed at 18 °C and were exposed, during adulthood, to either 15 °C or 25 °C. Here, we test whether (1) flies undergo stress at the two more extreme temperatures; (2) development at a given temperature enhances adult performance at such temperature (i.e. acclimation), and (3) populations with different biogeographical history show plasticity differences. Our findings show (1) an optimal performance at 18 °C only if flies were subjected to the same temperature as juveniles and adults; (2) the occurrence of developmental acclimation at lower temperatures; (3) detrimental effects of higher developmental temperature on adult performance; and (4) a minor impact of historical background on thermal response. Our study indicates that thermal plasticity during development may have a limited role in helping adults cope with warmer - though not colder - temperatures, with a potential negative impact on population persistence under climate change. It also emphasizes the importance of analysing the impact of temperature on all stages of the life cycle to better characterize the thermal limits.info:eu-repo/semantics/publishedVersio

    Slow and population specific evolutionary response to a warming environment

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    Adaptation to increasingly warmer environments may be critical to avoid extinction. Whether and how these adaptive responses can arise is under debate. Though several studies have tackled evolutionary responses under different thermal selective regimes, very few have specifically addressed the underlying patterns of thermal adaptation under scenarios of progressive warming conditions. Also, considering how much past history affects such evolutionary response is critical. Here, we report a long-term experimental evolution study addressing the adaptive response of Drosophila subobscura populations with distinct biogeographical history to two thermal regimes. Our results showed clear differences between the historically differentiated populations, with adaptation to the warming conditions only evident in the low latitude populations. Furthermore, this adaptation was only detected after more than 30 generations of thermal evolution. Our findings show some evolutionary potential of Drosophila populations to respond to a warming environment, but the response was slow and population specific, emphasizing limitations to the ability of ectotherms to adapt to rapid thermal shifts.info:eu-repo/semantics/publishedVersio

    Cardiogenic shock complicating acute coronary syndromes

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    INTRODUCTION: Despite advances in the treatment of patients with acute coronary syndromes (ACS), cardiogenic shock (CS) remains the leading cause of death in these patients. PURPOSE: Determine characteristics and management of patients with an ACS complicated by CS. Determine predictors of development of CS during hospitalization and predictors of in-hospital mortality. METHODS: Retrospective study of 2064 patients consecutively admitted for ACS in a Coronary Unit over a period of 4 years. RESULTS: During the years under study, 111 patients (5.4%) developed CS. Patients with CS were more likely to be older (69.8 ± 13.2 vs 63.5 ± 13.1 years, p<0.001); there were no significant differences in other clinical characteristics. Myocardial Infarction with ST segment elevation (STEMI) was more frequent in patients with CS (p<0.001). Patients with CS underwent less often coronary angiography (p<0.001), revascularization (p = 0.004) and were less treated with β-blocker (p <0.001) and ACE inhibitors therapy (p <0.001). In multivariate analysis, predictors of occurrence of CS during hospitalization were: tachycardia (OR 3.2, 95% CI 1.6-6.3), systolic blood pressure 1 (OR 3.5, 95% CI 1.8-6.8) at admission. The in-hospital mortality of patients with CS was 45%, compared with 1.7% in those who did not develop CS. Factors associated with an increased mortality in patients with CS included absence of coronary revascularization (OR 4.9, 95% CI 1.5-16.0), GFR <60ml/min (OR 4.4, 95% CI 1.3-15.6), advanced age (OR 6.4, 95% CI 1.6-26.2) and LVEF ≤ 35 % (OR 3.9, 95% CI 1.3-12.4). CONCLUSION: According to the literature, our review showed that CS in the context of ACS is associated with a high mortality. We identified clinical markers that are associated with the development of CS and may spot patients at risk earlier. Absence of coronary revascularization remains an independent predictor of mortality in CS

    Consequences of sexual harassment in sport for female athletes

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    Sexual harassment research was first undertaken in the workplace and educational settings. Research on sexual harassment in sport is scarce but has grown steadily since the mid-1980s. Even so, very little is known about the causes and/or characteristics and/or consequences of sexual harassment in sport settings. This article reports on the findings from interviews with 25 elite female athletes in Norway who indicated in a prior survey (N =572) that they had experienced sexual harassment from someone in sport. The consequences of the incidents of sexual harassment that were reported were mostly negative, but some also reported that their experiences of sexual harassment had had no consequences for them. “Thinking about the incidents”, a “destroyed relationship to the coach”, and “more negative view of men in general” were the most often negative consequences mentioned. In addition, a surprising number had chosen to move to a different sport or to drop out of elite sport altogether because of the harassment

    Dating stalagmite from Caverna do Diabo (Devil'S Cave) by TL and EPR techniques

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    A cylindrical fragment of stalagmite from Caverna do Diabo, State of Sao Paulo, Brazil, has been studied and dated by thermoluminescence and electron paramagnetic resonance techniques. The thermoluminescence glow curves of stalagmite samples and subsequently gamma irradiated, have shown rise of three peaks at 135, 180 and 265 degrees C. From electron paramagnetic resonance spectra of stalagmite was possible to clearly identify three paramagnetic centers in the g = 2.0 region: Centers I, II and III are due to, CO3- and CO33-, respectively. The additive method was applied to calculate the accumulated dose using thermoluminescence peak at 265 degrees C and the electron paramagnetic resonance signal at g = 1.9973 of CO2- radical. The ages of the different slices of stalagmite were determined from the D-ac-values and D-an-value, obtaining an average of 86410 for central slice, 53421 for second slice, 31490 for third slice and 46390 years B.P. for the central region of upper end.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ Sao Paulo, Inst Fis, Rua Matao,187 Cidade Univ, BR-05508090 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Ciencias Mar, Rua Doutor Carvalho de Mendonca 144, BR-11070100 Santos, SP, BrazilIPEN CNEN SP, Inst Pesquisas Energet & Nucl, Av Prof Lineu Prestes,2242 Cidade Univ, BR-05508000 Sao Paulo, SP, BrazilUniv Nacl San Agustin, Fac Ciencias Nat & Formales, Escuela Profes Fis, Av Independencia S-N, Arequipa, PeruUniv Sao Paulo, Escola Politecn, Dept Engn Met & Mat, Av Prof Mello Moraes 2463, BR-05508030 Sao Paulo, SP, BrazilDepartamento de Ciências do Mar, Universidade Federal de São Paulo, Rua Doutor Carvalho de Mendonça, 144, 11070-100 Santos, SP, BrazilFAPESP: 2014/03085-0CAPES: BEX-9612130Web of Scienc
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