910 resultados para Environmental influence


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This work is about the role that environment plays in the production of evolutionary significant variations. It starts with an historical introduction about the concept of variation and the role of environment in its production. Then, I show how a lack of attention to these topics may lead to serious mistakes in data interpretation. A statistical re-analysis of published data on the effects of malnutrition on dental eruption, shows that what has been interpreted as an increase in the mean value, is actually linked to increase of variability. In Chapter 3 I present the topic of development as a link between variability and environmental influence, giving a review of the possible mechanisms by which development influences evolutionary dynamics. Chapter 4 is the core chapter of the thesis; I investigated the role of environment in the development of dental morphology. I used dental hypoplasia as a marker of stress, characterizing two groups. Comparing the morphology of upper molars in the two groups, three major results came out: (i) there is a significant effect of environmental stressors on the overall morphology of upper molars; (ii) the developmental response increases morphological variability of the stressed population; (iii) increase of variability is directional: stressed individuals have increased cusps dimensions and number. I also hypothesized the molecular mechanisms that could be responsible of the observed effects. In Chapter 5, I present future perspectives for developing this research. The direction of dental development response is the same direction of the trend in mammalian dental evolution. Since malnutrition triggers the developmental response, and this particular kind of stressor must have been very common in our class evolutionary history, I propose the possibility that environmental stress actively influenced mammals evolution. Moreover, I discuss the possibility of reconsidering the role of natural selection in the evolution of dental morphology.

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Determining the habitat use of mobile marine species is important for understanding responses to climate change and aids the implementation of management and conservation measures. Inference of preferred habitat use has been greatly improved by combining satellite-based oceanographic data with animal tracking techniques. Although there have been several satellite-tracking studies on ocean sunfish Mola mola, limited information is available about either horizontal or vertical environmental preferences. In this study, both geographical movements and diving behaviour of ocean sunfish were explored together with the environmental factors influencing this species’ space use in the north-east Atlantic.

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Determining the habitat use of mobile marine species is important for understanding responses to climate change and aids the implementation of management and conservation measures. Inference of preferred habitat use has been greatly improved by combining satellite-based oceanographic data with animal tracking techniques. Although there have been several satellite-tracking studies on ocean sunfish Mola mola, limited information is available about either horizontal or vertical environmental preferences. In this study, both geographical movements and diving behaviour of ocean sunfish were explored together with the environmental factors influencing this species’ space use in the north-east Atlantic.

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Small pelagic fishes are particularly abundant in areas with high environmental variability (zones of coastal upwelling and areas of tidal mixing and river discharge), and because of this, their abundance suffers large inter-annual and inter-decadal fluctuations. In Portugal, the most important species in terms of landings are European sardine, Atlantic horse mackerel and Atlantic chub mackerel. Small pelagic fish landings account for 62.8 % of the total fish biomass and represent 32.7 % of the economical value of all catches. We have investigated trends in landings of these small pelagic fishes and detected the effects of environmental factors in this fishery. In order to explain the variability of landings of small pelagic fishes, we have used official landings (1965-2012) for trawling and purse seine fisheries and applied generalized linear models, using the North Atlantic Oscillation index (NAO) (annual and winter NAO index), sea surface temperature (SST), wind data (strength and North-South and East-West wind components) and rainfall, as explanatory variables. Regression analysis was used to describe the relationship between landings and SST. The models explained between 50.16 and 51.07 % of the variability of the LPUE, with the most important factors being winter NAO index, SST and wind strength. The LPUE of European sardine and Atlantic horse mackerel was negatively correlated with SST, and LPUE of Atlantic chub mackerel was positively correlated with SST. The use of landings of three important species of small pelagic fishes allowed the detection of variations in landings associated with changes in sea water temperature and NAO index.

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Turtles are among the most endangered vertebrate groups, and the main threats to populations are environmental pollution and habitat degradation. The species Phrynops geoffroanus, popularly known as “Geoffroy’s side-necked turtle”, has proliferated in polluted environments, where adverse conditions could influence their living habits and physiological condition. Studies that monitor the effects of environmental pollution are key to understanding the species’ biology and designing effective conservation strategies. Thus, the analysis of hematological and biochemical parameters has been shown to be important in assessing the health of wild animals and risks for the animal and ecosystem. This study aimed to assess the environmental influence on the physiology of a P. geoffroanus population through the evaluation of antioxidant status and responses to environmental stressors, compared to specimens from a place under controlled conditions. Blood samples of 60 specimens were collected, 30 from the Felicidade Stream, polluted environment, within the city of São José do Rio Preto, and 30 from the “Reginaldo Uvo Leone” breeding farm, Tabapuã, SP, a place under controlled conditions, whose samples constituted the control group. They were evaluated by hemogram and by determining thiobarbituric acid reactive species (TBARS), Trolox-equivalent antioxidant capacity (TEAC) and the activities of the antioxidant enzymes catalase and glucose-6-phosphate dehydrogenase (G6PDH). There was a wide variation in hematological parameters of P. geoffroanus from the urban environment. The red blood cell count and hemoglobin values were significantly less than those observed in animals from the breeding farm (P = 0.0004; P = 0.0371, respectively). There was a significant increase in the number of thrombocytes (P < 0.0001) and leukocytes (P < 0.0001) in the animals from Felicidade Stream. The stress indices were similar between the two groups (P = 0.4077). TBARS levels showed the cytotoxic potential of compounds in the urban environment, whose animals had elevated levels of lipid peroxidation (P < 0.0001), despite showing a response to environmental damages with increase in antioxidant capacity, as demonstrated by the TEAC assay (P = 0.0207). The lower catalase enzyme activity noted in individuals from the urban environment (P = 0.000184) could be due to the presence of inhibitory compounds. On the other hand, G6PDH activity was higher (P = 0.002962), where this enzyme acts in the generation of NADPH, which is used in several detoxification pathways. We conclude that environmental contamination can increase oxidative damages and generate physiological changes in this species. These data are very useful for the conservation of P. geoffroanus and turtles in general, and confirm that these techniques are effective in monitoring natural regions and that P. geoffroanus can serve as an environmental contamination bioindicator.

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Blood pressure (BP) and physical activity (PA) levels are inversely associated. Since genetic factors account for the observed variation in each of these traits, it is possible that part of their association may be related to common genetic and/or environmental influences. Thus, this study was designed to estimate the genetic and environmental correlations of BP and PA phenotypes in nuclear families from Muzambinho, Brazil. Families including 236 offspring (6 to 24 years) and their 82 fathers and 122 mothers (24 to 65 years) were evaluated. BP was measured, and total PA (TPA) was assessed by an interview (commuting, occupational, leisure time, and school time PA). Quantitative genetic modeling was used to estimate maximal heritability (h²), and genetic and environmental correlations. Heritability was significant for all phenotypes (systolic BP: h² = 0.37 ± 0.10, P < 0.05; diastolic BP: h² = 0.39 ± 0.09, P < 0.05; TPA: h² = 0.24 ± 0.09, P < 0.05). Significant genetic (r g) and environmental (r e) correlations were detected between systolic and diastolic BP (r g = 0.67 ± 0.12 and r e = 0.48 ± 0.08, P < 0.05). Genetic correlations between BP and TPA were not significant, while a tendency to an environmental cross-trait correlation was found between diastolic BP and TPA (r e = -0.18 ± 0.09, P = 0.057). In conclusion, BP and PA are under genetic influences. Systolic and diastolic BP share common genes and environmental influences. Diastolic BP and TPA are probably under similar environmental influences.

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Aim: This paper addresses issues arising in the literature regarding the environmental design of inpatient healthcare settings and their impact on care.

Background: Environmental design in healthcare settings is an important feature of the holistic delivery of healthcare. The environmental influence of the delivery of care is manifested by such things as lighting, proximity to bedside, technology, family involvement, and space. The need to respond rapidly in places such as emergency and intensive care can override space needs for family support. In some settings with aging buildings, the available space is no longer appropriate to the needs—for example, the need for privacy in emergency departments. Many aspects of care have changed over the last three decades and the environment of care appears not to have been adapted to contemporary healthcare requirements nor involved consumers in ascertaining environmental requirements. The issues found in the literature are addressed under five themes: the design of physical space, family needs, privacy considerations, the impact of technology, and patient safety.

Conclusion: There is a need for greater input into the design of healthcare spaces from those who use them, to incorporate dignified and expedient care delivery in the care of the person and to meet the needs of family.

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Determining the ecologically relevant spatial scales for predicting species occurrences is an important concept when determining species–environment relationships. Therefore species distribution modelling should consider all ecologically relevant spatial scales. While several recent studies have addressed this problem in artificially fragmented landscapes, few studies have researched relevant ecological scales for organisms that also live in naturally fragmented landscapes. This situation is exemplified by the Australian rock-wallabies’ preference for rugged terrain and we addressed the issue of scale using the threatened brush-tailed rock-wallaby (Petrogale penicillata) in eastern Australia. We surveyed for brush-tailed rock-wallabies at 200 sites in southeast Queensland, collecting potentially influential site level and landscape level variables. We applied classification trees at either scale to capture a hierarchy of relationships between the explanatory variables and brush-tailed rock-wallaby presence/absence. Habitat complexity at the site level and geology at the landscape level were the best predictors of where we observed brush-tailed rock-wallabies. Our study showed that the distribution of the species is affected by both site scale and landscape scale factors, reinforcing the need for a multi-scale approach to understanding the relationship between a species and its environment. We demonstrate that careful design of data collection, using coarse scale spatial datasets and finer scale field data, can provide useful information for identifying the ecologically relevant scales for studying species–environment relationships. Our study highlights the need to determine patterns of environmental influence at multiple scales to conserve specialist species such as the brush-tailed rock-wallaby in naturally fragmented landscapes.

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Post-transcriptional control of gene expression has gone from a curiosity involving a few special genes to a highly diverse and widespread set of processes that is truly pervasive in plant gene expression. Thus, Plant Cell readers interested in almost any aspect of plant gene expression in response to any environmental influence, or in development, are advised to read on. In May 2001, what has become the de facto third biennial Symposium on Post-Transcriptional Control of Gene Expression in Plants was held in Ames, Iowa. The meeting was hosted by the new Plant Sciences Institute of Iowa State University with additional funding from the National Science Foundation and the United States Department of Agriculture. In 1997, the annual University of California-Riverside Plant Physiology Symposium was devoted to this topic. This provided a wake-up call to the plant world, summarized in this journal (Gallie and Bailey-Serres, 1997), that not all gene expression is controlled at the level of transcription. This was expanded upon at a European Molecular Biology Organization Workshop in Leysin, Switzerland, in 1999 (Bailey-Serres et al., 1999). The 3-day meeting in Ames brought together a strong and diverse contingent of plant biologists from four continents. The participants represented an unusually heterogeneous group of disciplines ranging from virology to stress response to computational biology. The research approaches and techniques represented were similarly diverse. Here we discuss a sample of the many fascinating aspects of post-transcriptional control that were presented at this meeting; we apologize to those whose work is not described here.

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The photochemical and photophysical processes of many organic compounds are a function of the environment in which they are present. In this connection we have chosen to investigate the environmental perturbations on the photodimerization of coumarin,l and the results of our study in aqueous and micellar media are presented in this paper. Coumarin has historically been the subject of intense photochemical and spectroscopic interest, mainly as a consequence of its importance in biological systems. Coumarin has been chosen for our investigation as its fascinating photochemical behavior has been fairly well explored,2 and therefore the environmental influence, which is the subject of our concern, would be easily understandable.

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"Greenhouse heating" of the atmosphere due to trace gases seems apparent to those who model with averages but not to those who examine individual temperature records. Temperature trends are on the minds of all those concerned with the environmental influence of the increasing human population. The big problem remains - where and how do we take the Earth's temperature? ... In California, there are 112 temperature records for 1910 to 1989; all of them were used here to examine trends in annual temperature.

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A penning trap system called LPT (LANZHOU PENNING TRAP) is now being developed for precise mass measurements in IMP (Institute of Modern Physics). The most key component of LPT is a superconducting magnet. A Phi 156 mm warm bore and two cylinder good field regions with a distance of 220 mm are required for trapping ions and measurements. As the required homogeneity is better than 0.5 ppm, several complicated coaxial coils are used to produce such a magnetic field. The size and position of these coils are optimized by using a method combining linear program with multiobjective optimization. Superconducting shim coils and passive shim pieces are used to eliminate inevitable winding tolerances and environmental influence. The fringe field is decreased to 5 Gs at 2 m line from the center of the magnet by active shielding coils. The designs of the mechanical structure, the quench protection system are also introduced in this paper.

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洞穴次生沉积物(尤其是石笋)所包含的古环境、古气候信息是当今研究的热点,但它所包含的环境气候信息对外界的响应灵敏度如何,这是最为关注的问题。石笋的微层厚度变化及荧光强度变化是来自洞穴上覆土壤中的有机碳沉积产生的,这些有机碳是由雨季早期冲刷进入洞穴形成的微层,微层厚度变化及荧光强度变化包含了环境(植被)、气候(温度和降水量)信息,它们可作为环境、气候替代指标使用,但需要进行现代环境、气候的校正,以往研究仅从某个侧面进行研究,系统研究有机碳在岩溶洞穴系统的演化过程较少。本论文通过对四个洞穴系统(凉风洞、七星洞、将军洞和犀牛洞)的溶解有机碳及其荧光系统的研究,探讨了溶解有机碳及其荧光的演化及其对环境气候的响应,根据分析论述,得出如下几点认识: 1. 通过对四个岩溶洞穴系统中DOC浓度月际、季节、年际变化研究,洞穴滴水在春季及夏初具有较大的DOC浓度,而在秋季变化最小、浓度也是最低的。滴水点出现DOC峰值的时间不一致,有的在春季、有的则在夏初,一方面反映降水时间的提前或推迟,另一方面也反映了水在洞穴顶板内的运移途径的长短等过程。个别滴水点能在不同时间出现不同的DOC浓度峰值,可能反映了滴水点对降水的响应灵敏,或不同的径流途径在时间上的提前或推迟,水动力条件的不同造成滴水补给源运移路径的差异应该是产生滴水点DOC浓度具有多个峰值的原因。由于洞穴次生沉积物在DOC的参与下形成,季节性的DOC高浓度产生较厚微层,但对降水敏感的滴水点可能产生了不同厚度的微层,不仅具有季节性微层,可能还能产生降水模式的微层。 2. 洞穴系统中溶解有机碳和荧光的空间变化分析上,得出溶解有机碳浓度在各个洞穴系统中纵向和横向上是有变化的。在滴水中滴水点间DOC浓度也有空间变化,而洞穴之间变化差异不明显,可能与土壤有机碳进入洞穴的运移途径有关;在土壤水中溶解有机碳浓度空间变化能反映了土壤有机碳的来源,即表层50cm以上的土壤层是输入土壤的有机碳主要来源。 3. 根据三维荧光光谱,四个岩溶洞穴系统的DOC的荧光类型可分为三个范围,即类富里酸、类蛋白和紫外类富里酸、类腐殖酸、类蛋白的混合荧光类型。在其它洞穴滴水的研究中未发现类腐殖酸类型的荧光峰,四个洞穴系统滴水中也不具有该类型荧光峰。在与植被类型的联系上反映出森林植被下的荧光波长变化较小,而土壤覆盖较连续的荧光强度较稳定。 4. 荧光波长的变化,反映了输入滴水中有机碳物质类型的差异,即有机碳在空间分布上的不均匀性和植被差异导致荧光波长的变化。从土壤水到洞穴滴水,溶解有机碳与荧光强度具有很好的线性相关性,表明洞穴滴水溶解有机碳是土壤有机碳运移至滴水中;土壤有机碳运移过程沿运移途径产生一系列变化,滴水DOC浓度低于土壤溶解有机碳一个数量级。土壤水DOC在将军洞的荧光强度除受外界因素影响,还受到内滤效应导致DOC浓度与荧光的强度线性关系不明显。在溶解有机碳和荧光的空间变化关系上,应联系表层环境对它们的影响,对它们充分认识才能得出合理的空间变化推论。 5. 荧光强度在洞穴滴水的变化趋势,一方面反映表层环境的变化,另一方面可能因水动力条件的不同,产生荧光性物质滤除效应,在DOC浓度变化较小的将军洞表现得最突出。在季节性水流输入的凉风洞和犀牛洞、和有滴水长期输入的七星洞和将军洞塘水,前三个洞穴塘水溶解有机碳及其荧光强度都明显高于滴水的,而后一洞穴塘水的低于滴水的,可能洞内蒸发作用对后者影响小,这样洞穴次生沉积除以表层环境的影响,其洞内环境的变化也可能是影响它的一个因素,但相对于表层环境变化,洞内的变化是微小的。 6. 从四个洞穴系统DOC变化来看,DOC浓度变化对植被类型变化不是很灵敏。从原生性喀斯特森林→灌丛草坡→灌草丛→刺丛草坡的岩溶洞穴系统,虽然土壤水DOC浓度变化较大,反映了输入土壤的及土壤中有机碳的分解难易程度,但在洞穴滴水中DOC浓度变化不是很明显,都显示相近的浓度水平。由于输入土壤的有机碳更新周期长,在水运移过程中受不同时间段降解的有机碳溶解,且来源不同的有机碳混合程度不同,导致不能很好地反映当年输入的有机碳的含量变化,应该是造成洞穴滴水DOC浓度不能很好区分植被类型的原因。 7. DOC浓度变化响应于降水量,也响应于气温。春夏季,当降水量达到一定雨量值(如有效降水量)时,入渗的雨水使表层有机物质溶入土壤水中,土壤水下渗到洞穴滴水中后,滴水DOC浓度较大,荧光强度也较大。降水对DOC浓度有稀释作用,是造成部分月份DOC浓度下降的原因。在7月份以前洞穴滴水DOC就已达到最大浓度,在8~10月份因气温高、降水量偏少,可能对微生物有抑制作用,造成其分解有机碳活动减弱,导致DOC浓度变化差异小。这反映了洞穴滴水DOC浓度与气候关系比较密切,进一步证实利用洞穴次生沉积物微层的厚度变化来反映气候变化是可行的,至少可以作为一个辅助指标来运用。 8. DOC及其荧光受多种因素影响,我们分析了pH、HCO3-、SIC、PPCO2、洞穴盖层厚度和岩石的溶解对它们的影响。分析表明洞穴盖层厚度和Ca2+、Mg2+离子浓度变化对它们的影响较大,pH变化范围小,认为它对DOC及其荧光的影响较小;HCO3-、SIC和PPCO2与DOC和荧光强度分别具有一些较好的线性关系(置信度=90%),但总的趋势是线性关系不显著,这表明了HCO3-、SIC和PPCO2与DOC和荧光强度联系不明显,指出它们只是影响DOC及其荧光强度的一个次要因素,并不是主要因素。洞穴盖层厚度影响洞穴滴水DOC及其荧光,表明在应用洞穴次生沉积物记录指标反演洞穴环境变化的研究过程中,对于次生沉积物形成点的发生在洞穴顶板内的水文地化学过程应该有一个清晰的了解,才有可能获取完整、正确的信息。