957 resultados para Thermal stress index


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The ongoing process of ocean acidification already affects marine life and, according to the concept of oxygen- and capacity limitation of thermal tolerance (OCLTT), these effects may be exacerbated at the boarders of the thermal tolerance window. We studied the effects of elevated CO2 concentrations on clapping performance and energy metabolism of the commercially important scallop Pecten maximus. Individuals were exposed for at least 30 days to 4°C (winter) or to 10°C (spring/summer) at either ambient (0.04 kPa, normocapnia) or predicted future PCO2 levels (0.11 kPa, hypercapnia). Cold (4°C) exposed groups revealed thermal stress exacerbated by PCO2 indicated by a high mortality overall and its increase from 55% under normocapnia to 90% under hypercapnia. We therefore excluded the 4°C groups from further experimentation. Scallops at 10°C showed impaired clapping performance following hypercapnic exposure. Force production was significantly reduced although the number of claps was unchanged between normo- and hypercapnia exposed scallops. The difference between maximal and resting metabolic rate (aerobic scope) of the hypercapnic scallops was significantly reduced compared to normocapnic animals, indicating a reduction in net aerobic scope. Our data confirm that ocean acidification narrows the thermal tolerance range of scallops resulting in elevated vulnerability to temperature extremes and impairs the animal's performance capacity with potentially detrimental consequences for its fitness and survival in the ocean of tomorrow.

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The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response. Introduction

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Os enfermeiros não estão isentos das consequências do stress ocupacional, que embora psicológico, afeta a saúde física, constituindo um risco para a segurança e saúde quando persistente, levando ao aparecimento de Burnout. Avaliar o nível de stress e o nível de Burnout na amostra selecionada; Conhecer a relação entre as estratégias de coping e nível de stress vivenciado pelos enfermeiros. Estudo quantitativo, descritivo, correlacional e transversal. Amostra de 81 enfermeiros perioperatórios, maioritariamente do género feminino (74,1%), 66,6% dos inquiridos exercem funções nos Blocos Operatórios do Centro Hospitalar de Trás‐os‐Montes e Alto Douro, média de idades de 43 anos. A opção de trabalhar no Bloco Operatório, foi para 59,3% dos inquiridos imposta pela instituição. A experiência média neste serviço foi de 15 anos. Aplicados três instrumentos de avaliação: Maslach Burnout Inventory, Nurse Stress Index e Inventário de Resolução de Problemas. A amostra exibe um nível considerável de stress (M=81,25; DP=20,7). Observou‐se uma correlação estatisticamente significativa entre o nível de stress e o nível de Burnout (r=0,43; p<0,001); verificou‐se existir uma relação estatisticamente significativa entre o nível de stress e as estratégias de coping (r=‐0,28; p<0,05), contudo, esta relação traduziu uma relação inversa. Valores elevados de Burnout correspondem a valores elevados de stress; valores elevados nas estratégias de coping, corresponderam a níveis baixos de stress. A gestão do stress tem valorizado mais os indivíduos do que as organizações. Contudo, mais importante que prevenir o stress laboral e os riscos psicossociais, é a organização e a gestão do trabalho que deve ser prioritária.

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Research into families of children and young people with disability maintain that parents or caregivers seem to experience higher levels of global stress than parents of children without disabilities, thereby presenting a high risk of developing disorders in their health and quality of life. The aim of this study is to understand the differences in parental stress and social support among groups of parents whose children have different disabilities in the context of parental adjustment to disability. Considering that adjustment is related to the effectiveness with which the family uses its resources and the support of their social network, we intend to analyse the differences of stress and social support among groups of parents of children with different problems and to clarify the relationships between the variables under study in order to adapt family intervention strategies. For this purpose a comparative, descriptive-correlational study was undertaken. The convenience sample included 152 parents of children with different disabilities (82 with intellectual disability, 37 with motor problems and 33 with autism) supported by schools and institutions in Viseu. The instruments used were: a Portuguese version of the Parenting Stress Index (Abidin, 1995), the Social Support Questionnaire – short version (Pinheiro & Ferreira, 2001) and a Parental Questionnaire (demographic and family data). Data were collected in schools and institutions that support people with disabilities, located in the Municipality of Viseu (Portugal). The results revealed significant differences between groups of parents in the partial results of parental stress, specifically in the Hyperactivity/Distract (DI), Acceptability (AC) and Adaptability (AD), dimensions of the Child Domain subscale (CD stress) and the Role Restriction (RO), dimension of Parent Domain subscale (PD stress). With regard to social support dimensions, we found significant differences between parents in the extent and availability of the social support network (SSQN).

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This study examines the importance of thermal refugia along the majority of the geographical range of a key inter- tidal species (Patella vulgata Linnaeus, 1758) on the Atlantic coast of Europe. We asked whether differences between sun-exposed and shaded microhabitats were responsible for differences in physiological stress and ecological perfor- mance and examined the availability of refugia near equatorial range limits. Thermal differences between sun- exposed and shaded microhabitats are consistently associated with differences in physiological performance, and the frequency of occurrence of high temperatures is most probably limiting the maximum population densities sup- ported at any given place. Topographical complexity provides thermal refugia throughout most of the distribution range, although towards the equatorial edges the magnitude of the amelioration provided by shaded microhabitats is largely reduced. Importantly, the limiting effects of temperature, rather than being related to latitude, seem to be tightly associated with microsite variability, which therefore is likely to have profound effects on the way local popu- lations (and consequently species) respond to climatic changes.

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Livestock facilities, where animals carry their productive cycle, must have as main characteristic, the control of influence over climatic factors on animals. The environment variations can be controlled through the use of different ventilation systems. The objective of this research was to evaluate the influence of different environment conditioning systems on swine nursery. Three treatments have been tested: natural ventilation, cooled ventilation and forced ventilation. The climatic parameters evaluated were: air temperature, relative humidity and black globe temperature. The physiological parameters analyzed were: respiratory frequency and back fat thickness. Number of born alive piglets, average weight at weaning and number of weaned piglets were also evaluated parameters. The use of cooled ventilation systems were able to decreased animal's air temperature and respiratory frequency, and the black globe temperature and humidity index (WBGT) and the radiating thermal load (RTL).

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The swine breeder rearing environment directly affects the animal's performance. This research had the objective of developing a thermal, aerial and acoustic environmental evaluation pattern for boar housing. The experiment was carried on a commercial swine farm in Salto County -SP, Brazil. Thermal, aerial and acoustic environment data of rearing conditions were registered. Data were statistically analyzed using as threshold the ideal housing environment that leads to animal welfare. Results showed that ambient temperature was around 70% beyond normal range, while air relative humidity, air speed and gases concentration were within threshold values. Noise level data besides being within normal range did not present large variation. In relation to the fuzzy logic analysis it was possible to build up a scenario which indicated that the best welfare indexes to male swine breeders happens when thermal comfort index are close to 80%, and noise level is lower than 40 dB. In the other hand the worst welfare index occur in the sector where the thermal comfort values are below 40% at the same time that the noise level is higher than 80 dB leading to inadequate conditions to the animal, and may directly interfere in the reproduction system performance.

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Time-resolved Z-scan measurements were performed in a Nd(3+)-doped Sr(0.61)Ba(0.39)Nb(2)O(6) laser crystal through ferroelectric phase transition. Both the differences in electronic polarizability (Delta alpha(p)) and cross section (Delta sigma) of the neodymium ions have been found to be strongly modified in the surroundings of the transition temperature. This observed unusual behavior is concluded to be caused by the remarkable influence that the structural changes associated to the ferro-to-paraelectric phase transition has on the 4f -> 5d transition probabilities. The maximum polarizability change value Delta alpha(p)=1.2x10(-25) cm(3) obtained at room temperature is the largest ever measured for a Nd(3+)-doped transparent material.

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The Piracicaba, Capivari, and Jundiai River Basins (RB-PCJ) are mainly located in the State of So Paulo, Brazil. Using a dynamics systems simulation model (WRM-PCJ) to assess water resources sustainability, five 50-year simulations were run. WRM-PCJ was developed as a tool to aid decision and policy makers on the RB-PCJ Watershed Committee. The model has 254 variables. The model was calibrated and validated using available information from the 80s. Falkenmark Water Stress Index went from 1,403 m(3) person (-aEuro parts per thousand 1) year (-aEuro parts per thousand 1) in 2004 to 734 m(3) P (-aEuro parts per thousand 1) year (-aEuro parts per thousand 1) in 2054, and Xu Sustainability Index from 0.44 to 0.20. In 2004, the Keller River Basin Development Phase was Conservation, and by 2054 was Augmentation. The three criteria used to evaluate water resources showed that the watershed is at crucial water resources management turning point. The WRM-PCJ performed well, and it proved to be an excellent tool for decision and policy makers at RB-PCJ.

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The effects of some composition variables on the development of multiple emulsions by one-step method were evaluated and their morphology characterized. The formulations that remained stable during the period of the test were submitted to centrifugation and thermal stress tests. The stability and the morphology of multiple droplets were affected not only by the type and concentration of the surfactants employed, but also by the water/oil ratios used. The results suggest that the formation of multiple droplets could involve a combination of transitional and catastrophic phase inversions. The results provide improved knowledge about the one-step emulsification method, a simplified process to prepare multiple emulsions when compared to the two-steps method.

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Intraspecific Drosophila studies suggest that resistance to heal and cold stresses are largely independent and that correlations across life cycle stages are low whereas comparisons of Drosophila species indicate correlations between heat and cold resistance as well as between resistance levels in different life cycle stages. These inconsistent results may reflect differences in associations among traits at the interspecific and intraspecific levels or interspecific correlations arising because of correlated selection pressures. These alternatives were tested using Drosophila serrata, D. birchii and hybrids derived from these species. Variation among hybrid lines and families was used to test associations at the interspecific level while intraspecific variation was examined using isofemale lines of D. serrata. There was a significant association between adult heat knockdown time at 38 degreesC and adult cold resistance in one set of hybrid lines. An association between female knockdown resistance to heat and larval heat resistance was also evident in one set of hybrids. Resistance to heat anti cold at the larval stage were not correlated at either the intraspecific or interspecific levels. At the intraspecific level, lan al heat resistance and two measures of adult heat resistance were uncorrelated. Moreover, adult and larval cold resistance measures were not correlated at either the intraspecific or interspecific levels. These results suggest that there are no associations between resistance to heat and cold extremes and that extreme temperature resistance is largely independent across life cycle stages at both the intraspecific and interspecific levels. Species associations may therefore arise from correlated selection pressures rather than trait correlations. (C) 2000 The Linnean Society of London.

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The specific identity of endosymbiotic dinoflagellates (Symbiodinium spp.) from most zooxanthellate corals is unknown. In a survey of symbiotic cnidarians from the southern Great Barrier Reef (GBR), 23 symbiont types were identified from 86 host species representing 40 genera. A majority (>85%) of these symbionts belong to a single phylogenetic clade or subgenus (C) composed of closely related (as assessed by sequence data from the internal transcribed spacer region and the ribosomal large subunit gene), yet ecologically and physiologically distinct, types. A few prevalent symbiont types, or generalists, dominate the coral community of the southern GBR, whereas many rare and/or specific symbionts, or specialists, are found uniquely within certain host taxa. The comparison of symbiont diversity between southern GBR and Caribbean reefs shows an inverse relationship between coral diversity and symbiont diversity, perhaps as a consequence of more-rapid diversification of Caribbean symbionts. Among clade C types, generalists C1 and C3 are common to both Caribbean and southern GBR symbiont assemblages, whereas the rest are regionally endemic. Possibly because of environmental changes in the Caribbean after geographic isolation through the Quaternary period, a high proportion of Caribbean fauna associate with symbiont taxa from two other distantly related Symbiodinium clades (A and B) that rarely occur in Pacific hosts. The resilience of Porites spp. and the resistance of Montipora digitata to thermal stress and bleaching are partially explained by their association with a thermally tolerant symbiont type, whereas the indiscriminant widespread bleaching and death among certain Pacific corals, during El Nino Southern Oscillation events, are influenced by associations with symbionts possessing higher sensitivity to thermal stress.

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Composite resin is a widely-used direct tooth coloured restorative material. Photoactivation of the polymerisation reaction can be achieved by visible blue light from a range of light sources, including halogen lamps, metal halide lamps, plasma arc lamps, and Light Emitting Diode (LED) lights. Concerns have been raised that curing lights may induce a temperature rise that could be detrimental to the vitality of the dental pulp during the act of photoactivation. The present study examined heat changes associated with standardised class V restorations on the buccal surface of extracted premolar teeth, using a curing time of 40 seconds. The independent effects of type of light source, resin shade and remaining tooth thickness were assessed using a matrix experimental design. When a conventional halogen lamp, a metal halide lamp and two different LED lights were compared, it was found that both LED lamps elicited minimal thermal changes at the level of the dental pulp, whereas the halogen lamp induced greater changes and the metal halide lamp caused the greatest thermal insult of all the light sources. These thermal changes were influenced by resin shade, with different patterns for LED versus halogen or halide sources. Thermal stress reduced as the remaining thickness of tooth structure between the pulp and the cavity floor increased. From these results, it is concluded that LED lights produce the least thermal insult during photopolymerisation of composite resins.

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Passive techniques as an alternative to artificial cooling can bring important energy, environmental, financial, operational and qualitative benefits. However, regions such as the wet tropics can reach high levels of thermal stress in which passive means alone are unable to provide appropriate thermal comfort standards for some parts of the year. Despite a great accumulation of empirical information on the passive performance of houses for either free-running or conditioned modes, very little work has been done on the thermal performance of buildings that can operate with a mixed-running strategy in warm-humid climates. Buildings with such design features are able to balance the needs for comfort, privacy, and energy efficiency during different periods of the year. As free-running and conditioned modes are believed by many to be 'opposite' approaches, and have been presented as separate strategies, this paper demonstrates that not all parameters are directly opposite and a possible dual-mode integrated operation can be used for warm-humid locations for maximum comfort and minimum energy requirements. For this purpose, simulation runs using ESP-R (University of Strathclyde, ESRU, UK) were based on the climate data of Darwin (Australia) and on the ventilation styles of the house: free running and conditioned. Design features applicable to both, i.e. for a dual mode operation could be identified and the differences between conditioned and free running were demonstrated and proved not to be totally conflicting and therefore suitable for a dual mode operation. Different daily usage profiles (five use patterns were defined), and zoning of sleeping and living areas are presented. The dual mode use patterns compared to the base case house, for all the user possibilities, had improved performances of 17-52%, when compared to the free-running mode and 66-98% when compared to the conditioned mode. Simulation runs using other warm-humid climates (Miami, USA; Sao Luis, Brazil; Kuala Lumpur, Malaysia) were also conducted and compared to the results found for Darwin. (C) 2002 Elsevier Science Ltd. All rights reserved.