875 resultados para Encountering the past in nature : essays in environmental history
Resumo:
The human exploitation of marine resources is characterised by the preferential removal of the largest species. Although this is expected to modify the structure of food webs, we have a relatively poor understanding of the potential consequences of such alteration. Here, we take advantage of a collection of ancient consumer tissues, using stable isotope analysis and SIBER to assess changes in the structure of coastal marine food webs in the South-western Atlantic through the second half of the Holocene as a result of the sequential exploitation of marine resources by hunter-gatherers, western sealers and modern fishermen. Samples were collected from shell middens and museums. Shells of both modern and archaeological intertidal herbivorous molluscs were used to reconstruct changes in the stable isotopic baseline, while modern and archaeological bones of the South American sea lion Otaria flavescens, South American fur seal Arctocephalus australis and Magellanic penguin Spheniscus magellanicus were used to analyse changes in the structure of the community of top predators. We found that ancient food webs were shorter, more redundant and more overlapping than current ones, both in northern-central Patagonia and southern Patagonia. These surprising results may be best explained by the huge impact of western sealing on pinnipeds during the fur trade period, rather than the impact of fishing on fish populations. As a consequence, the populations of pinnipeds at the end of the sealing period were likely well below the ecosystem's carrying capacity, which resulted in a release of intraspecific competition and a shift towards larger and higher trophic level prey. This in turn led to longer and less overlapping food webs.
Resumo:
A simple cloud point extraction procedure is presented for the preconcentration of copper in various samples. After complexation by 4-hydroxy-2-mercapto-6-propylpyrimidine (PTU), copper ions are quantitatively extracted into the phase rich in Triton X-114 after centrifugation. Methanol acidified with 0.5 mol L-1 HNO3 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). Analytical parameters including concentrations for PTU, Triton X-114 and HNO3, bath temperature, centrifugation rate and time were optimized. The influences of the matrix ions on the recoveries of copper ions were investigated. The detection limits (3SDb/m, n=4) of 1.6 ng mL-1 along with enrichment factors of 30 for Cu were achieved. The proposed procedure was applied to the analysis of environmental samples.
Resumo:
This study is concerned with 'nature' specifically as the subject-matter of physics, or natural science, as described by Aristotle in his "Physics". It also discusses the definitions of nature, and more specifically physical nature, provided by Avicenna (d. 1037) and Averroes (d. 1198) in their commentaries on Aristotle's "Physics". Avicenna and Averroes share Aristotle's conception of nature as a principle of motion and rest. While according to Aristotle the subject matter of physics appears to be nature, or what exists by nature, Avicenna believes that it is the natural body, and Averroes holds that the subject matter of physics or natural science consists in the natural things, in what constitutes a slight shift in focus.
Resumo:
All aerobic organisms have to deal with the toxicity of oxygen. Oxygen enables more efficient energy production compared to anaerobic respiration or fermentation, but at the same time reactive oxygen species (ROS) are being formed. ROS can also be produced by external factors such as UV-radiation and contamination. ROS can cause damage to biomolecules such as DNA, lipids and proteins and organisms try to keep the damage as small as possible by repairing biomolecules and metabolizing ROS. All ROS are not harmful, because they are used as signaling molecules. To cope against ROS organism have an antioxidant (AOX) system which consists both enzymatic and non-enzymatic AOX defense. Some AOX are produced by the organism itself and some are gained via diet. In this thesis I studied environmentally caused changes in the redox regulation of different wild vertebrate animals to gain knowledge on the temporal, spatial and pollution-derived-effects on the AOX systems. As study species I used barn swallow, ringed seal and the Baltic salmon. For the barn swallow the main interest was the seasonal fluctuation in the redox regulation and its connection to migration and breeding. The more contaminated ringed seals of the Baltic Sea were compared to seals from cleaner Svalbard to investigate whether they suffered from contaminant induced oxidative stress. The regional and temporal variation in redox regulation and regional variation in mRNA and protein expressions of Baltic salmon were studied to gain knowledge if the salmon from different areas are equally stressed. As a comparative aspect the redox responses of these different species were investigated to see which parts of the AOX system are substantial in which species. Certain parts of AOX system were connected to breeding and others to migration in barn swallows, there was also differences in biotransformation between birds caught from Africa and Finland. The Baltic ringed seal did not differ much from the seals from Svalbard, despite the difference in contaminant load. A possible explanation to this could be the enhanced AOX mechanisms against dive-associated oxidative stress in diving air-breathing animals, which also helps to cope with ROS derived from other sourses. The Baltic salmon from Gulf of Finland (GoF) showed higher activities in their AOX defense enzymes and more oxidative damage than fish from other areas. Also on mRNA and proteomic level, stress related metabolic changes were most profound in in the fish from GoF. Mainly my findings on species related differences followed the pattern of mammals showing highest activities and least damage and birds showing lower activities and most damage, fish being intermediate. In general, the glutathione recycling-related enzymes and the ratio of oxidized and reduced glutathione seemed to be the most affected parameters in all of the species.
Resumo:
The European Council has invited the European Commission to present the first macro-regional strategy – the EU Strategy for the Baltic Sea Region (EUSBSR) on the 14th of December 2007, primarily to address collective challenges and opportunities of the Region and also to engender cohesion in support of an European integration policy. However, macro-regional strategies conceived to aid European integration and territorial cohesion were viewed by academics with skepticism, obscuring the strategies’ potential impact. This thesis intends to investigate and measure the added value of the EUSBSR in order to analyze its impact on regional development and its feasibility as a guide for future programs intending to strengthen European cohesion and integration. To determine the added value of the EUSBSR the thesis is organized into three sections, so as to address environmental, social, and economic concerns, respectively. The first case examines EU-Russia cooperation in an environmental context to investigate how environmental cooperation with an external neighbor could forge increased cohesion in a macro-regional setting. To figure the added cooperation that academic cooperation among universities would contribute to social dimension, the work has chosen several study results. Lastly, to measure out the added value for the economic strategy objective, the study employs the project for Improved Global Competitiveness in an example of ‘A Baltic Sea Region Program for Innovation, Cluster and SME-Networks’ as an economic plan.
Resumo:
La pratique du design industriel dans la province canadienne de l’Alberta est en pleine croissance. Ses activités sont principalement concentrées à Edmonton et à Calgary, qui sont les plus grandes villes de la province. On y trouve des studios de design de renom, des communautés de design complexes et des programmes universitaires de design bien établis. Cependant, la pratique du design industriel albertaine est sous-développée en comparaison avec celle du reste du Canada et il y a peu de recherches et de documentation sur le design industriel en Alberta. Dans ce projet de mémoire, la pratique du design industriel en Alberta a été explorée depuis une approche historique. Pour pallier le manque de documentation, la collecte de données a été faite par une recherche qualitative, des entretiens narratifs et une recherche quantitative statistique. Une base d’information historique sur le design industriel albertain a été établie puis située par rapport au développement de la pratique du design industriel ailleurs au Canada. Les facteurs, événements et tendances dans l’histoire de la pratique du design industriel en Alberta ont été identifiés. De plus, le développement de la pratique du design industriel de l’Alberta a été comparé à celui du Québec et de l’Ontario. Les retombées de cette étude indiquent que la pratique du design industriel en Alberta présente quatre domaines de spécialisations distincts se développant depuis les années 1980. La pratique du design industriel en Alberta est sous-développée en comparaison à celui du Québec et de l’Ontario, mais elle peut devenir plus compétitive, au niveau canadien, avec plus de soutien gouvernemental, de meilleures relations avec l’industrie manufacturière et les institutions académiques, une communauté de design plus unifiée et en portant une plus grande attention aux domaines les plus prometteurs de l’industrie. Ces informations supportent une meilleure compréhension de la pratique du design industriel en Alberta et pourront informer les praticiens, enseignants et administrateurs du domaine du design industriel dans la province. Finalement, le mémoire servira de base à d’autres projets de recherche sur les changements potentiels dans la pratique du design industriel en Alberta et l’étude du design canadien et des industries de design régionales.
Resumo:
Il s'agit d'une hypothèse largement répandue que l’égo-dystonie et l’égo-syntonie caractérisent les obsessions dans les troubles des conduites alimentaires (TCA) et que ces facteurs sont cliniquement pertinents pour la conceptualisation et le traitement des TCA. Cependant, les résultats empiriques sur ce sujet sont rares. Compte tenu du chevauchement reconnu entre les TCA, notamment l'anorexie et la boulimie (BN), et le trouble obsessionnel-compulsif (TOC) dans la phénoménologie et les caractéristiques psychologiques, un programme de thérapie cognitive basée sur les inférences (TBI) de 24 semaines, démontré efficace dans le traitement des TOC, a été adapté pour traiter les TCA. La recherche sur le TOC suggère que la transformation des pensées intrusives en obsessions est liée à la mesure dans laquelle les pensées intrusives menacent des perceptions fondamentales du soi et de l’identité. Cette thèse a pour objectif d'examiner le lien entre l’égo-dystonie et les TCA. Pour se faire, nous avons exploré le lien entre la nature égo-dystone des obsessions chez les patients souffrant d'un TCA et la peur de l'image de soi. Nous avons également étudié la relation entre la sévérité des symptômes TCA et l’égo-dystonie dans les obsessions. En outre, nous avons investigué les différences dans la présence de pensées égo-dystones et de peur face à son identité entre des sujets non-cliniques et des personnes atteintes d’un TCA. Enfin, nous avons comparé le degré d’égo-dystonie dans les pensées de personnes atteintes d’un TCA à celui dans les pensées d’individus souffrant d’un TOC. L’égo-dystonie dans les pensées a été mesurée par l'Ego Dystonicity Questionnaire (EDQ) et le degré de peur face à l’identité a été mesuré par le Fear of Self Questionnaire (FSQ) d’une part dans un échantillon de femmes souffrant d’un TCA (n = 57) et d’autre part dans un échantillon de participantes non-cliniques (n = 45). Les résultats révèlent que l’égo-dystonie et la peur face à l’identité étaient fortement corrélées à la fois dans l’échantillon clinique et non-clinique. Les scores de l’EDQ n’étaient pas significativement corrélés à la sévérité des symptômes TCA à l'exception de la sous-échelle d’irrationalité de l’EDQ qui était fortement associée à la sévérité des comportements compulsifs compensatoires. Les participantes souffrant d'un TCA avaient des scores significativement plus élevés à l’EDQ et au FSQ que les sujets non-cliniques. Ensuite, une étude de cas décrit l’application du programme de thérapie cognitive TBI pour une femme de 35 ans avec un diagnostic de BN. La pathologie TCA s’est significativement améliorée au cours de la TBI et six mois suivant la thérapie. Cette étude de cas met en évidence l'importance de cibler les idées surévaluées, les doutes et le raisonnement face au soi et à l’identité dans le traitement psychologique pour les TCA. Enfin, l’objectif final de cette thèse était d’examiner les changements au niveau (1) des symptômes TCA, (2) du degré d’égo-syntonie dans les obsessions, et (3) des mesures de peur face à l’identité, de motivation, d’humeur et d’anxiété au cours de la TBI et au suivi post six mois. L’égo-dystonie, la peur face à l’identité, les symptômes TCA et le stade motivationnel ont été mesurés chez 15 femmes souffrant de BN au cours du traitement et six mois après la TBI. Quatre vingt pourcent de l’échantillon, soit 12 des 15 participantes, ont démontré une diminution cliniquement significative des symptômes TCA et 53% ont cessé leurs comportements compensatoires au suivi post six mois. Les retombées cliniques relatives au traitement des TCA sont discutées.
Resumo:
The Union Territory of Pondicherry prior to its merger with the Indian Union was a French Colony. The erstwhile territory of Pondicherry along with its hamlets, namely, KARAIKKAL, MAHE and YANAM was administered by the French Regime. Before it was established by French in 1 6 74 A.D. it was part of Vijayanagara Empire. Prior to this, Pondicherry was a part of the Kingdom of Chola and Pallava Kings. During French Regime, the laws which were in force in France in relation to administration of civil and criminal justice were extended to the erstwhile Territory of Pondicherry. Thus while Pondicherry stood influenced by the Inquisitorial system since the beginning of the 18th century, the neighboring states forming part of the Indian Union since Independence came under the Influence of the British system, viz. accusatorial system. The territory of Pondicherry, for administrative reasons, came to be merged with the Indian Union in the early 60's. Following the merger, the Indian administration sought to extent its own laws from time to time replacing erstwhile French Laws, however, subject to certain savings. Thus the transitional period witnessed consequential changes in the administration of the territory, including the sphere of judicial system. Since I 963, the Union Territory of Pondicherry was brought under the spell of the Indian Legal System The people in Pondicherry ' thus have had the benefit of experiencing both the svstems. Their experiences will be of much help to those who undertake comparative studies in law. The plus and minus points of the respective systems help one to develop a detachment that helps independent evaluation of the svstents. The result of these studies could be relevant in revitalising our criminal systems.The present system is evaluated in the light of the past system. New dimensions are added by way' of an empirical study also.
Resumo:
Sediments are the reserve of environmental variation and analysis gives the diverse nature of the environmental chemical pattern. Present attempt provides an insight on the biogeochemistry (BGC) of sediment in selected stations of Kerala coast, India. Sampling along the Kerala coast was done during May – June 2009 in cruise no: 267 of Fishery and Oceanographic Research Vessel, Sagar Sampada. Eleven samples were collected from four stations - Cape, Trivandrum, Kollam and Cochin. Study of organic matter (OM) is significant as it exerts a strong control on the diagenic alterations in the sediment. Samples were analyzed for their Texture; OM- Protein, Carbohydrate, Tannin and lignin, Lipid; Trace metal; Total phosphorus and CHN. Among the eleven analyzed sediment, sample from Cochin station has high clay (>30%) and silt (>40%) content. The rest of the stations showed elevated amount of sand content. Generally the investigation reveals an inverse relation between lipid with other OM- Protein, Carbohydrate, Tannin and lignin. The order of relative distribution of OM were Protein > Carbohydrate > Tannin and Lignin > Lipid. High concentration of trace metal, Fe was found at Kollam and Cochin. Trace metal concentration was directly related to OM distribution. But C/N and Fe/P ratios were inversely related to OM and trace metal.
Resumo:
Previous research has shown that richer people are more likely to engage in an environmentalcause. We extend it by considering the joint effect between subjective income and a set of macroeconomicvariables. For doing so, we employ the fifth wave of the World Values Survey (WVS).This study provides clear evidence that even when both factors matter, people´s attitudes cruciallydepend on the interaction effect. Hence, those measures that affect the characteristics of thecountry would also change the disposition to be involved.
Resumo:
This paper deals with second-generation Barbadians or 'Bajan-Brits', who have decided to,return' to the birthplace of their parents, focusing on their reactions to matters relating to race relations and racialised identities. The importance of race and the operation of the 'colour-class' system in the Caribbean are established at the outset. Based on fifty-two qualitative in-depth interviews, the paper initially considers the positive things that the second-generation migrants report about living in a majority black country and the salience of such racial affirmation as part of their migration process. The paper then presents an analysis of the narratives provided by the Bajan-Brits concerning their reactions to issues relating to race relations in Barbadian society. The impressions of the young returnees provide clear commentaries on what are regarded as (i) the 'acceptance of white hegemony' within Barbadian society, (ii) the occurrence of de facto 'racial segregation, (iii) perceptions of the 'existence of apartheid, and (iv) 'the continuation of slavery'. The account then turns to the contemporary operation of the colour-class system. It is concluded that, despite academic arguments that the colour-class dimension has to be put to one side as the principal dimension of social stratification in the contemporary Caribbean, the second-generation migrants are acutely aware of the continued existence and salience of such gradations within society. Thus, the analysis not only serves to emphasise the continued importance of racial-based stratification in the contemporary Caribbean, but also speaks of the 'hybrid' and 'in-between' racialised identities of the second-generation migrants.
Resumo:
The performance of the atmospheric component of the new Hadley Centre Global Environmental Model (HadGEM1) is assessed in terms of its ability to represent a selection of key aspects of variability in the Tropics and extratropics. These include midlatitude storm tracks and blocking activity, synoptic variability over Europe, and the North Atlantic Oscillation together with tropical convection, the Madden-Julian oscillation, and the Asian summer monsoon. Comparisons with the previous model, the Third Hadley Centre Coupled Ocean-Atmosphere GCM (HadCM3), demonstrate that there has been a considerable increase in the transient eddy kinetic energy (EKE), bringing HadGEM1 into closer agreement with current reanalyses. This increase in EKE results from the increased horizontal resolution and, in combination with the improved physical parameterizations, leads to improvements in the representation of Northern Hemisphere storm tracks and blocking. The simulation of synoptic weather regimes over Europe is also greatly improved compared to HadCM3, again due to both increased resolution and other model developments. The variability of convection in the equatorial region is generally stronger and closer to observations than in HadCM3. There is, however, still limited convective variance coincident with several of the observed equatorial wave modes. Simulation of the Madden-Julian oscillation is improved in HadGEM1: both the activity and interannual variability are increased and the eastward propagation, although slower than observed, is much better simulated. While some aspects of the climatology of the Asian summer monsoon are improved in HadGEM1, the upper-level winds are too weak and the simulation of precipitation deteriorates. The dominant modes of monsoon interannual variability are similar in the two models, although in HadCM3 this is linked to SST forcing, while in HadGEM1 internal variability dominates. Overall, analysis of the phenomena considered here indicates that HadGEM1 performs well and, in many important respects, improves upon HadCM3. Together with the improved representation of the mean climate, this improvement in the simulation of atmospheric variability suggests that HadGEM1 provides a sound basis for future studies of climate and climate change.