826 resultados para Ecological and environmental anthropology


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The study of investigating the spatial and temporal variability of macroinvertebrate and their relation to hydrology, hydraulic and environmental factors was done along the Sigi River during two sampling periods in the dry (March) and wet (May) periods of 2012. The river was demarcated based on slope ranges and five river zones were identified as mountains streams (MS), upper foothills (UF), lower foothills (LF), rejuvenated foothills (REJ) and mature lower river (MR). Samples of macroinvertebrate were collected from the five river zones and measurements of hydrological (discharge), hydraulics (Depth, velocity and Froude number) and Environmental (pH, Temperature, substrate, conductivity) parameters were done in each zone. In characterizing the macroinvertebrate assemblages along the Sigi River diversity indices (number of taxa, total abundances, Margalef richness index and ShannonWiener index) were calculated and the most representative species for the spatial and temporal variation were identified. Melanoides and Afronurous showed differences in abundance in two samplings periods while Cleopatra, Potamonautes, Ephemerythus, Neoperla, Caenis, Ceratogomphus and Cheumatopsyche showed significant difference among the river zones. Spearman rank correlation and Distance Linear Model (DistLM) used to revealed physical factors governing the macroinvertebrate assemblages distribution. The study demonstrated that the variation of physical factors like discharge, temperature, conductivity and pH have an important role in the spatial distribution of macroinvertebrate assemblages along the river and the life cycle of macroinvertebrate (Afronurus) is important in determining the temporal variability.

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Tese de doutoramento, Biologia (Biologia Marinha e Aquacultuta), Universidade de Lisboa, Faculdade de Ciências, 2014

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This paper reviews the options available to policy makers in their efforts to reduce the negative impacts of urban freight transport. After providing a summary of the categories of negative impacts that can be targeted together with the specific policy initiatives available, it reviews the actions taken by policy makers across in cities within four countries (UK, Japan, the Netherlands and France). In the case of the UK and Japan attention is focused on a single city as an exemplar of some of the developments. In the case of the Netherlands and France the discussion is wider.

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Air pollution represents a serious risk not only to environment and human health, but also to historical heritage. In this study, air pollution of the Oporto Metropolitan Area and its main impacts were characterized. The results showed that levels of CO, PM10 and SO2 have been continuously decreasing in the respective metropolitan area while levels of NOx and NO2 have not changed significantly. Traffic emissions were the main source of the determined polycyclic aromatic hydrocarbons (PAHs; 16 PAHs considered by U.S. EPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) in air of the respective metropolitan area. The mean concentration of 18 PAHs in air was 69.9±39.7 ng m−3 with 3–4 rings PAHs accounting for 75% of the total ΣPAHs. The health risk analysis of PAHs in air showed that the estimated values of lifetime lung cancer risks considerably exceeded the health-based guideline level. Analytical results also confirm that historical monuments in urban areas act as passive repositories for air pollutants present in the surrounding atmosphere. FTIR and EDX analyses showed that gypsum was the most important constituent of black crusts of the characterized historical monument Monastery of Serra do Pilar classified as “UNESCO World Cultural Heritage”. In black crusts, 4–6 rings compounds accounted approximately for 85% of ΣPAHs. The diagnostic ratios confirmed that traffic emissions were the major source of PAHs in black crusts; PAH composition profiles were very similar for crusts and PM10 and PM2.5.

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The recent changes on power systems paradigm requires the active participation of small and medium players in energy management. With an electricity price fluctuation these players must manage the consumption. Lowering costs and ensuring adequate user comfort levels. Demand response can improve the power system management and bring benefits for the small and medium players. The work presented in this paper, which is developed aiming the smart grid context, can also be used in the current power system paradigm. The proposed system is the combination of several fields of research, namely multi-agent systems and artificial neural networks. This system is physically implemented in our laboratories and it is used daily by researchers. The physical implementation gives the system an improvement in the proof of concept, distancing itself from the conventional systems. This paper presents a case study illustrating the simulation of real-time pricing in a laboratory.

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The occurrence of seven pharmaceuticals and two metabolites belonging to non-steroidal anti-inflammatory drugs and analgesics therapeutic classes was studied in seawaters. A total of 101 samples covering fourteen beaches and five cities were evaluated in order to assess the spatial distribution of pharmaceuticals among north Portuguese coast. Seawaters were selected in order to embrace different bathing water quality (excellent, good and sufficient). Acetaminophen, ketoprofen and the metabolite hydroxyibuprofen were detected in all the seawater samples at maximum concentrations of 584, 89.7 and 287 ng L− 1, respectively. Carboxyibuprofen had the highest seawater concentration (1227 ng L− 1). The temporal distribution of the selected pharmaceuticals during the bathing season showed that, in general, higher concentrations were detected in August and September. The environmental risk posed by the pharmaceuticals detected in seawaters towards different trophic levels (fish, daphnids and algae) was also assessed. Only diclofenac showed hazard quotients above one for fish, representing a potential risk for aquatic organisms. These results were observed in seawaters classified as excellent bathing water. Additional data is needed in order to support the identification and prioritization of risks posed by pharmaceuticals in marine environment.

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The use of buffers to maintain the pH within a desired range is a very common practice in chemical, biochemical and biological studies. Among them, zwitterionic N-substituted aminosulfonic acids, usually known as Good’s buffers, although widely used, can complex metals and interact with biological systems. The present work reviews, discusses and updates the metal complexation characteristics of thirty one commercially available buffers. In addition, their impact on biological systems is also presented. The influences of these buffers on the results obtained in biological, biochemical and environmental studies, with special focus on their interaction with metal ions, are highlighted and critically reviewed. Using chemical speciation simulations, based on the current knowledge of the metal–buffer stability constants, a proposal of the most adequate buffer to employ for a given metal ion is presented.

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Intracellular, vertically transmitted bacteria form complex and intimate relationships with their hosts. Wolbachia, maternally transmitted α- proteobacteria, live within the cells of numerous arthropod species. Wolbachia are famous master manipulators of insect reproduction: to favour their own spread they can induce male killing, parthenogenesis or cytoplasmic incompatibility. Wolbachia can also protect various insects from pathogens, which makes them a promising tool for the control of vector-borne diseases. Mosquitoes with Wolbachia have already been released in the wild to eliminate dengue. Yet, how Wolbachia manipulate their hosts remains largely unknown.(...)

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This paper demonstrates the significance of culture in examining the relationshipbetween democratic capital and environmental performance.The aim is to examine the relationship among scores on the Environmental Performance Index and the two dimensions of cross cultural variation suggested by Ronald Inglehart and Christian Welzel. Significantional interrelationships among democracy, cultural and environmental sustaintability measures could be found, following the regression results. Firstly, higher levels of democratic capital stock are associated with better environmental performance. Secondly importance to distinguish between cultural groups could be confirmed.

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Double degree

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Most metabolic functions are optimized within a narrow range of body temperatures, which is why thermoregulation is of great importance for the survival and overall fitness of an animal. It has been proposed that lizards will thermoregulate less precisely in low thermal quality environments, where the costs associated with thermoregulation are high; in the case of lizards, whose thermoregulation is mainly behavioural, the primary costs ofthermoregulation are those derived from locomotion. Decreasing thermoregulatory precision in costly situations is a strategy that enhances fitness by allowing lizards to be more flexible to changing environmental conditions. It allows animals to maximize the benefits of maintaining a relatively high body temperature while minimizing energy expenditure. In situations where oxygen concentration is low, the costs of thermoregulation are relatively high (i.e. in relation to the amount of oxygen available for metabolic functions). As a result, it is likely that exposures to hypoxic conditions induce a decrease in the precision of thermoregulation. This study evaluated the effects of hypoxia and low environmental thermal quality, two energetically costly conditions, on the precision and level of thermoregulation in the bearded dragon, Pogona vitticeps, in an electronic temperature-choice shuttle box. Four levels of hypoxia (1O, 7, 5 and 4% 02) were tested. Environmental thermal quality was manipulated by varying the rate of temperature change (oTa) in an electronic temperature-choice shuttle box. Higher oT a's translate into more thermally challenging environments, since under these conditions the animals are forced to move a greater number of times (and hence invest more energy in locomotion) to maintain similar temperatures than at lower oTa's. In addition, lizards were tested in an "extreme temperatures" treatment during which air temperatures of the hot and cold compartments of the shuttle box were maintained at a constant 50 and 15°C respectively. This was considered the most thermally challenging environment. The selected ambient (T a) and internal body temperatures (Tb) of bearded dragons, as well as the thermoregulatory precision (measured by the central 68% ofthe Ta and T b distribution) were evaluated. The thermoregulatory response was similar to both conditions. A significant increase in the size of the Tb range, reflecting a decrease in thermoregulatory precision, and a drop in preferred body temperature of ~2 °C, were observed at both 4% oxygen and at the environment of lowest thermal quality. The present study suggests that in energetically costly situations, such as the ones tested in this study, the bearded dragon reduces energy expenditure by decreasing preferred body temperature and minimizing locomotion, at the expense of precise behavioural thermoregulation. The close similarity of the behavioural thermoregulatory response to two very different stimuli suggests a possible common mechanism and neuronal pathway to the thermoregulatory response.

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Scientists have overwhelmingly concluded that global warming occurs as a consequence of human activities and that climate change, combined with the depletion of resources, could have catastrophic consequences for the human civilization later this century. However, in political circles and in the public sphere these conclusions are not taken seriously, or they are laid aside for future generations to deal with; at the same time, significant efforts are being deployed to discredit the scientific evidence. In this thesis I have studied the positions of climate scientists as well as those of climate change deniers, and I also examined how their points of view are likely to impact the interests and habits of corporations and citizens. The work of Thomas Homer-Dixon was used as an important source for analyzing the complex interaction between our natural, economic, and social systems, and John Dewey's pattern of inquiry provided the theoretical foundation for an analysis of the current crisis and its possible solutions. No concerted action to deal with climate change has yet been taken by the leaders of the Western world; I corroborated data from four reliable sources (Hansen, 2009; IPCC, 2007; Lynas, 2007; Steffen, 2011) regarding several development scenarios and their likely consequences on greenhouse gas emissions, and I concluded that a future temperature increase of more than 2°C appears now as unavoidable. In the light of this conclusion I argue that education for increasing the resilience of smaller communities is a realistic alternative that can offer some hope in dealing with the challenges ahead.

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Introduction: Chez les mammifères, la naissance de nouveaux neurones se poursuit à l’âge adulte dans deux régions du cerveau: 1) l’hippocampe et 2) la zone sous-ventriculaire du prosencéphale. La neurogenèse adulte n’est pas un processus stable et peut être affectée par divers facteurs tels que l’âge et la maladie. De plus, les modifications de la neurogenèse peuvent être à l’origine des maladies de sorte que la régulation ainsi que le rétablissement de la neurogenèse adulte doivent être considérés comme d’importants objectifs thérapeutiques. Chez la souris saine ou malade, la neurogenèse hippocampale peut être fortement régulée par l’enrichissement environnemental ainsi que par l’activité physique. Cependant, lors même que l’activité physique et l’enrichissement environnemental pourraient contribuer au traitement de certaines maladies, très peu d’études porte sur les mécanismes moléculaires et physiologiques responsables des changements qui sont en lien avec ces stimuli. Objectifs et hypothèses: Les principaux objectifs de cette étude sont de caractériser les effets de stimuli externes sur la neurogenèse et, par le fait même, d’élucider les mécanismes sous-jacents aux changements observés. En utilisant le modèle d’activité physique volontaire sur roue, cette étude teste les deux hypothèses suivantes: tout d’abord 1) qu’une période prolongée d’activité physique peut influencer la neurogenèse adulte dans le prosencéphale et l’hippocampe, et 2) que l’activité volontaire sur roue peut favoriser la neurogenèse à travers des stimuli dépendants ou indépendants de la course. Méthodes: Afin de valider la première hypothèse, nous avons utilisé un paradigme incluant une activité physique volontaire prolongée sur une durée de six semaines, ainsi que des analyses immunohistochimiques permettant de caractériser l’activité de précurseurs neuronaux dans la zone sous-ventriculaire et l’hippocampe. Ensuite, pour valider la seconde hypothèse, nous avons utlisé une version modifiée du paradigme ci-dessous, en plaçant les animaux (souris) soit dans des cages traditionnelles, soit dans des cages munies d’une roue bloquée soit dans des cages munies d’une roue fonctionnelle. Résultats: En accord avec la première hypothèse, l’activité physique prolongée volontaire a augmenté la prolifération des précurseurs neuronaux ainsi que la neurogenèse dans le gyrus dentelé de l’hippocampe comparativement aux animaux témoins, confirmant les résultats d’études antérieures. Par ailleurs, dans ce paradigme, nous avons aussi observé de la prolifération acrue au sein de la zone sous-ventriculaire du prosencéphale. De plus, en accord avec la seconde hypothèse, les souris placées dans une cage à roue bloquée ont montré une augmentation de la prolifération des précurseurs neuronaux dans l’hippocampe comparable à celle observée chez les souris ayant accès à une roue fonctionnelle (coureurs). Cependant, seuls les animaux coureurs ont présenté une augmentation de la neurogenèse hippocampale. Conclusions: Ces résultats nous ont permis de tirer deux conclusions nouvelles concernant les effets de l’activité physique (course) sur la neurogenèse. Premièrement, en plus de la prolifération et de la neurogenèse dans le gyrus dentelé de l’hippocampe, la prolifération dans la zone sous-ventriculaire du prosencéphale peut être augmentée par l’activité physique sur roue. Deuxièmement, l’environnement dans lequel l’activité physique a lieu contient différents stimuli qui peuvent influencer certains aspects de la neurogenèse hippocampale en l’absence d’activité physique sur roue (course).

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The main objectives of the present investigation were to evaluate the qualitative and quantitative distribution of natural cyanobacterial population and their ecobiological properties along the Cochin estuary and their application in aquaculture systems as a nutritional supplement due to their nutrient-rich biochemical composition and antioxidant potential. This thesis presents a detailed account of the distribution of cyanobacteria in Cochin estuary, an assessment of physico-chemical parameters and the nutrients of the study site, an evaluation of the effect of physico-chemical parameters on cyanobacterial distribution and abundance, isolation, identification and culturing of cyanobacteria, the biochemical composition an productivity of cyanobacteria, and an evaluation of the potential of the selected cyanobacteria as antioxidants against ethanol induced lipid peroxidation. The pH, salinity and nutritional requirements were optimized for low-cost production of the selected cyanobacterial strains. The present study provides an insight into the distribution, abundance, diversity and ecology of cyanobacteria of Cochin estuary. From the results, it is evident that the ecological conditions of Cochin estuary support a rich cyanobacterial growth.