905 resultados para Restoration and conservation


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This article details the use of photographic rectification as support for the graphic documentation of historical and archaeological heritage and specifically the southern facade of the Torre del Pretori (Praetorium Tower) in Tarragona. The Praetorium Tower is part of a larger monumental complex and one of the towers that connected different parts of the Tarraco Provincial Forum, the politic-administrative centre of the ancient capital of Hispania Citerioris. It is therefore a valuable example of the evolution of Roman urban architecture. The aim of this project is to provide accurate graphic documentation of the structure to facilitate the restoration and conservation of the tower, as well as to provide a more profound architectural and archaeological understanding of the Roman forum. The use of photographic rectification enabled us to overcome the spatial and time difficulties involved in collecting data caused by the size and location of the building. Specific software made it easier to obtain accurate two-dimensional images. For this reason, in our case, photographic rectification helped us to make a direct analysis of the monument and facilitated interpretation of the architectural stratigraphy. We currently separate the line of research into two concepts: the construction processes and the architecture of the building. The documentation collected permitted various analyses: the characterisation of the building modules, identification of the tools used to work the building materials, etc. In conclusion, the use of orthoimages is a powerful tool that permits the systematic study of a Roman building that has evolved over the centuries and is now in a modern urban context.

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Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate change. It is expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human development. In this article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological responses. We also discuss current knowledge gaps and conservation challenges. Expected climate alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and fires. Recent observations, which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental changes. Accurate forecasts of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding hydrology. Long-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate change. Investments should focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Africa. Scientists, policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge.

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In Chile, mediterranean climate conditions only occur in the Central Zone (ChMZ). Despite its small area, this mediterranean climate region (med-region) has been recognised as a hotspot for biodiversity. However, in contrast to the rivers of other med-regions, the rivers in the ChMZ have been studied infrequently, and knowledge of their freshwater biodiversity is scarce and fragmented. We gathered information on the freshwater biodiversity of ChMZ, and present a review of the current knowledge of the principal floral and faunal groups. Existing knowledge indicates that the ChMZ has high levels of endemism, with many primitive species being of Gondwanan origin. Although detailed information is available on most floral groups, most faunal groups remain poorly known. In addition, numerous rivers in the ChMZ remain completely unexplored. Taxonomic specialists are scarce, and the information available on freshwater biodiversity has resulted from studies with objectives that did not directly address biodiversity issues. Research funding in this med-region has a strong applied character and is not focused on the knowledge of natural systems and their biodiversity. Species conservation policies are urgently required in this highly diverse med-region, which is also the most severely impacted and most populated region of the country.

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Brown trout is a cold-adapted freshwater species with restricted distribution to headwater streams in rivers of the South European peninsulas, where populations are highly vulnerable because Mediterranean regions are highly sensitive to the global climatic warming. Moreover, these populations are endangered due to the introgressive hybridization with cultured stocks. Individuals from six remnant populations in Western Mediterranean rivers were sequenced for the complete mitochondrial DNA control region and genotyped for 11 nuclear markers. Three different brown trout lineages were present in the studied region. Significant genetic divergence was observed among locations and a strong effect of genetic drift was suggested. An important stocking impact (close to 25%) was detected in the zone. Significant correlations between mitochondrial-based rates of hatchery introgression and water flow variation suggested a higher impact of stocked females in unstable habitats. In spite of hatchery introgression, all populations remained highly differentiated, suggesting that native genetic resources are still abundant. However, climatic predictions indicated that suitable habitats for the species in these rivers will be reduced and hence trout populations are highly endangered and vulnerable. Thus, management policies should take into account these predictions to design upstream refuge areas to protect remnant native trout in the region

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Paraphrasing what Gregory Bateson says on evolution, we might say that: "Immunology has long been badly taught. In particular, students - and even professional immunologists - acquire theories of immunological activity without any deep understanding of what problems these theories attempt to solve."

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Diabetes mellitus represents a serious public health problem owing to its global prevalence in the last decade. The causes of this metabolic disease include dysfunction and/or insufficient number of β cells. Existing diabetes mellitus treatments do not reverse or control the disease. Therefore, β-cell mass restoration might be a promising treatment. Several restoration approaches have been developed: inducing the proliferation of remaining insulin-producing cells, de novo islet formation from pancreatic progenitor cells (neogenesis), and converting non-β cells within the pancreas to β cells (transdifferentiation) are the most direct, simple, and least invasive ways to increase β-cell mass. However, their clinical significance is yet to be determined. Hypothetically, β cells or islet transplantation methods might be curative strategies for diabetes mellitus; however, the scarcity of donors limits the clinical application of these approaches. Thus, alternative cell sources for β-cell replacement could include embryonic stem cells, induced pluripotent stem cells, and mesenchymal stem cells. However, most differentiated cells obtained using these techniques are functionally immature and show poor glucose-stimulated insulin secretion compared with native β cells. Currently, their clinical use is still hampered by ethical issues and the risk of tumor development post transplantation. In this review, we briefly summarize the current knowledge of mouse pancreas organogenesis, morphogenesis, and maturation, including the molecular mechanisms involved. We then discuss two possible approaches of β-cell mass restoration for diabetes mellitus therapy: β-cell regeneration and β-cell replacement. We critically analyze each strategy with respect to the accessibility of the cells, potential risk to patients, and possible clinical outcomes.

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A wild bee community in southern St. Catharines, Ontario, Canada, was studied from 2003 to 2012 to analyze the effects of primary succession on abundance and diversity. At a former landfill site near Brock University, which previously contained no bees, the number of bees and bee species was expected to increase rapidly following measures to restore the site to grassy meadow habitat. The Intermediate Disturbance Hypothesis (IDH) states that over time, succession occurs. Abundance and diversity increase initially and peak when pioneers coexist with specialized species, then decline because of competitive exclusion. Alternatively, abundance and diversity may continue to increase and stabilize without declining. Bees were sampled repeatedly among years from newer restoration sites (revegetated in 2003), older restoration sites on the periphery of the former landfill (revegetated in 2000), and nearby low disturbance grassy field (i.e. control) sites. In the newer sites, bee abundance and diversity increased then decreased while in older restoration and control sites mainly decreased. This pattern of succession matches the general predictions of the IDH, although declines were at least partially related to drought. By 2006, total bee abundance levels converged among all sites, indicating rapid colonization and succession, and by 2012 diversity levels were similar among sites as well, suggesting that the bee community was fully restored or nearly so within the ten-year study period.

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The present study on the sustainability of medicinal plants in Kerala economic considerations in domestication and conservation of forest resources. There is worldwide consensus on the fact that medicinal plants are important not only in the local health support systems but in rural income and foreign exchange earnings. Sustainability of medicinal plants is important for the survival of forest dwellers, the forest ecosystem, conserving a heritage of human knowledge and overall development through linkages. More equitable sharing of the benefits from commercial utilization of the medicinal plants was found essential for the sustainability of the plants. Cultivation is very crucial for the sustainability of the sector. Through a direct tie-up with the industry, the societies can earn more income and repatriate better collection charges to its members. Cultivation should be carried out in wastelands, tiger reserves and in plantation forests. In short, the various players in the in the sector could find solution to their specific problems through co-operation and networking among them. They should rely on self-help rather than urging the government to take care of their needs. As far as the government is concerned, the forest department through checking over- exploitation of wild plants and the Agriculture Dept. through encouraging cultivation could contribute to the sustainable development of the medicinal plant sector.

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Present work deals with the studies on energy requirement and convervation in selected fish harvesting systems.Modem fishing is one of the most energy intensive methods of food production. Fossil fuels used for motorised and mechanised fishing are nonrenewable and limited. Most of the environmental problems that confront mankind today are connected to the use of energy in one way or another. Code of Conduct for Responsible Fisheries (FAO, 1995) highlights the need for efficient use of energy in the fisheries sector. Information on energy requirement in different fish harvesting systems, based on the principles of energy analysis, is entirely lacking in respect of Indian fisheries. Such an analysis will provide an unbiased decision making support for maximising the yield per unit of non-renewable energy use, from different fishery resource systems, by rational deployment of harvesting systems. In the present study, results of investigations conducted during 1997-2000 on energy requirement in selected fish harvesting systems and approaches to energy conservation in fishing, are presented along with a detailed description of the fish harvesting systems and their operation. The content of the thesis is organised into 8 Chapters.

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Analiza las causas de polución y algunas de las acciones que han tomado los gobiernos para la conservación del medio ambiente. Ofrece tres experimentos con explicaciones paso a paso para el aprendizaje por descubrimiento. Los experimentos hacen hincapié en la necesidad del niño de investigar. Hay glosario, bibliografía y direcciones de páginas webs para ampliar información.

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Two types of ecological thresholds are now being widely used to develop conservation targets: breakpoint-based thresholds represent tipping points where system properties change dramatically, whereas classification thresholds identify groups of data points with contrasting properties. Both breakpoint-based and classification thresholds are useful tools in evidence-based conservation. However, it is critical that the type of threshold to be estimated corresponds with the question of interest and that appropriate statistical procedures are used to determine its location. On the basis of their statistical properties, we recommend using piecewise regression methods to identify breakpoint-based thresholds and discriminant analysis or classification and regression trees to identify classification thresholds.

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