987 resultados para Euphrates River--Maps--Early works to 1800


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The commensal microbiota impacts specific immune cell populations and their functions at peripheral sites, such as gut mucosal tissues. However, it remains unknown whether gut microbiota control immunity through regulation of hematopoiesis at primary immune sites. We reveal that germ-free mice display reduced proportions and differentiation potential of specific myeloid cell progenitors of both yolk sac and bone marrow origin. Homeostatic innate immune defects may lead to impaired early responses to pathogens. Indeed, following systemic infection with Listeria monocytogenes, germ-free and oral antibiotic-treated mice display increased pathogen burden and acute death. Recolonization of germ-free mice with a complex microbiota restores defects in myelopoiesis and resistance to Listeria. These findings reveal that gut bacteria direct innate immune cell development via promoting hematopoiesis, contributing to our appreciation of the deep evolutionary connection between mammals and their microbiota.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The severe problems caused by large phytoplankton populations in the River Meuse date back to the beginning of the 1980s. However, no clear relationship can be established between an increase of algal growth and dissolved nutrient concentrations, at least in the Belgian part of the river. Most probably, plankton algae start developing in France, utilizing large inputs of phosphorus from some of the tributaries: this point will be investigated further, as well as the effect of a reduction in the releases of phosphorus. A mathematical model helps to understand the main factors which control algal growth: underwater light, temperature, discharge and grazing by zooplankton. The last is a major loss process in summer and, as shown by recent observations, may trigger a seasonal succession leading to dominance by large phytoplankton taxa. With regard to water quality, eutrophication is a major problem in drinking-water treatment (filter clogging, etc.) and large numbers of decomposing algae may adversely affect the oxygen budget of the river. On the other hand, algal photosynthesis is the most important oxygen source at periods of low discharge, and reduced algal production may result in dramatic oxygen decreases in heavily polluted stretches of the river.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

River structure and functioning are governed naturally by geography and climate but are vulnerable to natural and human-related disturbances, ranging from channel engineering to pollution and biological invasions. Biological communities in river ecosystems are able to respond to disturbances faster than those in most other aquatic systems. However, some extremely strong or lasting disturbances constrain the responses of river organisms and jeopardise their extraordinary resilience. Among these, the artificial alteration of river drainage structure and the intense use of water resources by humans may irreversibly influence these systems. The increased canalisation and damming of river courses interferes with sediment transport, alters biogeochemical cycles and leads to a decrease in biodiversity, both at local and global scales. Furthermore, water abstraction can especially affect the functioning of arid and semi-arid rivers. In particular, interception and assimilation of inorganic nutrients can be detrimental under hydrologically abnormal conditions. Among other effects, abstraction and increased nutrient loading might cause a shift from heterotrophy to autotrophy, through direct effects on primary producers and indirect effects through food webs, even in low-light river systems. The simultaneous desires to conserve and to provide ecosystem services present several challenges, both in research and management.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Geology is the science that studies the Earth, its composition, structure and origin in addition to past and present phenomena that leave their mark on rocks. So why does society need geologists? Some of the main reasons are listed below: - Geologists compile and interpret information about the earth’s surface and subsoil, which allows us to establish the planet’s past history, any foreseeable changes and its relationship with the rest of the solar system. - Society needs natural resources (metals, non-metals, water and fossil fuels) to survive. The work of geologists is therefore a key part of finding new deposits and establishing a guide for exploring and managing resources in an environmentally-friendly way. - The creation of geological maps allows us to identify potential risk areas and survey different land uses; in other words, they make an essential contribution to land planning and proposing sustainable development strategies in a region. - Learning about Geology and the proper use of geological information contributes to saving lives and reducing financial loss caused by natural catastrophes such as earthquakes, tsunamis, volcanic eruptions, flooding and landslides, while also helping to develop construction projects, public works, etc. Through the proposed activities we aim to explain some of the basic elements of the different specialities within the field of Geological Sciences. In order to do this, four sessions have been organised that will allow for a quick insight into the fields of Palaeontology, Mineralogy, Petrology and Tectonics.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Geology is the science that studies the Earth, its composition, structure and origin in addition to past and present phenomena that leave their mark on rocks. So why does society need geologists? Some of the main reasons are listed below: - Geologists compile and interpret information about the earth’s surface and subsoil, which allows us to establish the planet’s past history, any foreseeable changes and its relationship with the rest of the solar system. - Society needs natural resources (metals, non-metals, water and fossil fuels) to survive. The work of geologists is therefore a key part of finding new deposits and establishing a guide for exploring and managing resources in an environmentally-friendly way. - The creation of geological maps allows us to identify potential risk areas and survey different land uses; in other words, they make an essential contribution to land planning and proposing sustainable development strategies in a region. - Learning about Geology and the proper use of geological information contributes to saving lives and reducing financial loss caused by natural catastrophes such as earthquakes, tsunamis, volcanic eruptions, flooding and landslides, while also helping to develop construction projects, public works, etc. Through the proposed activities we aim to explain some of the basic elements of the different specialities within the field of Geological Sciences. In order to do this, four sessions have been organised that will allow for a quick insight into the fields of Palaeontology, Mineralogy, Petrology and Tectonics.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Esta tese desenvolvida na linha de pesquisa Política e Cultura destaca o interesse pelos fenômenos da transmissão do conhecimento intelectual. A tese reconstrói a expressão da cultura política medieval germânica pela ótica de dois poetas, Walther von der Vogelweide e Wolfram von Eschenbach, integrantes da aristocracia guerreira. Os suportes teóricos dos Sprüche, sentenças de natureza política de Vogelweide e do Parzifal de Eschenbach, foram fundamentais para compreender o posicionamento político e cultural alemão frente às transformações que afetaram a Cristandade no período de fins do século XII ao início do século XIII. Esse período foi marcado pelo confronto de Papas e Imperadores em torno do direito de exercer a autoridade no âmbito do Sacro Império Romano-Germânico. O movimento cruzadista, o renascimento urbano e a ascensão de novos atores sociais burgueses integram o conjunto dos elementos a serem levados em conta na elaboração da tese. A ideia norteadora do trabalho tornou necessário recorrer a obras literárias com objetivo de elucidar questões de natureza histórica, tendo claro que a Literatura não é um contraponto da História e o texto resultante contribua para ressignificar a produção política da cultura medieval e um melhor entendimento dos mecanismos do poder na Alemanha medieval. No plano teórico-metodológico recorremos à chamada História Cultural fornecendo uma visão integradora dos planos político, social e econômico.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The importance of the process of Neolithization for the genetic make-up of European populations has been hotly debated, with shifting hypotheses from a demic diffusion (DD) to a cultural diffusion (CD) model. In this regard, ancient DNA data from the Balkan Peninsula, which is an important source of information to assess the process of Neolithization in Europe, is however missing. In the present study we show genetic information on ancient populations of the South-East of Europe. We assessed mtDNA from ten sites from the current territory of Romania, spanning a time-period from the Early Neolithic to the Late Bronze Age. mtDNA data from Early Neolithic farmers of the Starcevo Cris culture in Romania (Carcea, Gura Baciului and Negrilesti sites), confirm their genetic relationship with those of the LBK culture (Linienbandkeramik Kultur) in Central Europe, and they show little genetic continuity with modern European populations. On the other hand, populations of the Middle-Late Neolithic (Boian, Zau and Gumelnita cultures), supposedly a second wave of Neolithic migration from Anatolia, had a much stronger effect on the genetic heritage of the European populations. In contrast, we find a smaller contribution of Late Bronze Age migrations to the genetic composition of Europeans. Based on these findings, we propose that permeation of mtDNA lineages from a second wave of Middle-Late Neolithic migration from North-West Anatolia into the Balkan Peninsula and Central Europe represent an important contribution to the genetic shift between Early and Late Neolithic populations in Europe, and consequently to the genetic make-up of modern European populations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is the second River Dart Fisheries Survey produced by the Devon River Authority; which was carried out from April to July, 1969. The objective was to examine the distribution and relative abundance of salmonid fish in the River Dart, in order to assess the possibility or desirability, of increasing salmon smolt production of the river by artificial propagation or other means. In addition to the tributaries examined in the 1965 survey, further sections were studied on the River Hems and Holy Brook and reference should be made to the River Survey Report, 1965 for introductory information. The method includes the choice of sections and sampling techniques. The results go through the number/type/class of fishes counted while the survey took place and distribution patterns within the different transects/brooks. The discussion tries to remark the importance of understanding the differences between 1965 and 1969 surveys. The Appendix contains tables with totals of salmonid fish found and distribution sizes for each section, population density tables and a map with new surveyed sections.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is the River Erme Fisheries Survey, 1965 by the Devon River Authority. The survey was carried out during April and May 1965, with the principal object being the determination of the abundance and distribution of salmonid fish in the River Erme in relation to the discharge from Stowford Paper Mills, Ivybridge. It contains a brief introduction of general aspects of the catchment, chemistry, pollution, biology and fisheries in the river, methodology that looks at the selected transects and techniques for sampling, results and recommendations. It contains tables with totals of all salmonid fish found at each section, size distribution of trout, surface area of section and population density.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is the River Plym Salmon Action Plan Final document produced by the Environment Agency in 2003. This final Salmon Action Plan (SAP) for the River Plym catchment has been produced after consideration of feedback from external consultation. It provides a list of the agreed issues and actions for the next five years to maintain and improve the River Lynher salmon stock. These issues and actions follow on from the detailed analysis of the catchment, which is presented in the River Plym SAP Consultation document.The actions presented within this final Salmon Action Plan clarify the important issues and factors currently limiting the salmon stock on the river. The resolution of these issues should ensure that a sustainable salmon population will be maintained for future generations. The main objective of the River Plym SAP therefore, is to maintain, improve and develop the River Plym salmon stocks to a sustainable level that, on the basis of historic catch records, the catchment can clearly support. The River Plym has failed to pass its conservation limit since 1996, and the consultees felt very strongly that there were three major factors limiting the salmon stock of the River Plym.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is the River Yealm Salmon Action Plan Final document produced by the Environment Agency in 2003. This final Salmon Action Plan (SAP) for the River Yealm catchment has been produced after consideration of feedback from external consultation. It provides a list of the agreed issues and actions for the next five years to maintain and improve the River Yealm salmon stock. The actions presented within this Salmon Action Plan clarify the important issues and factors currently limiting the salmon stock on the river. The resolution of these issues should ensure that a sustainable salmon population will be maintained for future generations. An attempt has been made to cost these actions, identify possible sources of funding and to provide a timescale for action. The main objective of the River Yealm SAP is to maintain, improve and develop the River Yealm salmon stocks to a sustainable level that, on the basis of historic catch records, the catchment can clearly support.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is the River Taw Salmon Action Plan Final document produced by the Environment Agency in 2000. This final Salmon Action Plan (SAP) for the River Taw catchment has been produced after consideration of feedback from external consultation. The SAP provides a list of the issues and actions which were agreed for a five-year programme to maintain and improve the River Taw salmon stock. Some of these actions have already been delivered before finalising the SAP, but others have yet to be addressed. An attempt has been made to estimate the cost of the actions, identify possible sources of funding and the timescale under which they will be dealt with. The Taw salmon stock is currently failing to meet its spawning target. However, there was a period of compliance in the 1990s following a decade of failure through the 1980s. The freshwater environment of the Taw has improved in recent years. The actions presented in this SAP are perceived as those that are required to address, as far as possible, the important issues and factors currently limiting the salmon stock on the river. This SAP aims to promote long term collaboration between the Agency and other interested parties in managing the River Taw salmon stock and fisheries.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is the River Lemon (Teign catchment) fisheries survey report produced by South West Water Authority in 1979. This report aims to determine the penetration of Salmon into the River Lemon System and to a lesser degree estimate the population of resident salmonids. Five sections were surveyed being easily accessible and fishable by electro fishing methods.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is the River Avon (including Glazebrook) fisheries survey 1978 report produced by South West Water Authority in 1978. This report aims to determine the penetration of Salmon into the River Avon system and to a lesser degree estimate the population of resident salmonids and other indigenous species. Six sections were electro fished at accessible points as detailed below. All fish were identified and measured. Each section was fished through three times to take the majority of the resident species. Small specimens of salmonid fry, eels and lamprey were common in almost all River Avon sections with the exception of Shipley bridge and Avon Dam but due to the mesh size of the standard dip nets used, many slipped through making accurate number estimation impossible.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A avaliação da qualidade dos solos e a redução da Mata Atlântica tem sido alvo de diversas pesquisas no Brasil e no mundo, principalmente quando estes estão atrelados ao recorte espacial de Unidades de Conservação. No entanto, tem sido difícil para os gestores dessas unidades a avaliação dos impactos ambientais gerados ao longo dos anos nas bacias hidrográficas, principalmente pela falta de investimentos. Esta dissertação teve por objetivo geral avaliar o atual estágio de degradação da bacia hidrográfica do Córrego da Caçada pertencente à Área de Proteção Ambiental Federal de Cairuçu, no município de Paraty RJ, analisando quantitativamente e qualitativamente a redução dos fragmentos de Mata Atlântica e estabelecendo relações com a degradação física e química dos solos dentro e fora dos fragmentos florestais. A metodologia utilizada para a redução ou avanço dos fragmentos de Mata Atlântica baseou-se no uso de fotografias aéreas do ano de 1956 e imagens de satélite de 2012, onde possibilitou a avaliação espaço-temporal do uso e cobertura das terras, através da produção de um mapa temático final. Além disso, foram elaborados mapas temáticos de reconhecimento da área de estudo, como o de hipsometria, de declividade, de orientação e forma das encostas, além da geração de perfis topográficos. Para a avaliação da qualidade física, química e biológica dos solos foram determinadas as curvas de distribuição granulométrica, a densidade relativa dos grãos sólidos e a densidade aparente, porosidade total, os limites de liquidez e plasticidade, a estabilidade dos agregados em água, análises morfológicas, a saturação de bases, a capacidade de troca catiônica (CTC), a saturação por alumínio, fósforo, pH e o carbono orgânico. Para tal, foi realizada a abertura de três perfis, sendo um em área de fragmento florestal e dois em áreas de pasto. O resultado das análises permitiu, segundo a Sociedade Brasileira de Ciência do solo, a classificação de dois tipos de solos na bacia, sendo: Cambissolo Háplico Tb Distrófico Típico em área fragmento florestal e em área de pasto, e um Latossolo Amarelo Tb Distrófico Típico em área de pasto. Os resultados de laboratório mostraram que os solos avaliados têm baixa fertilidade e valores variados nos resultados de física do solo. No entanto, além do histórico de uso do solo caracterizado pelas práticas rudimentares do manejo empregado pelos Caiçaras, o clima predominante na região possibilita um regime pluviométrico anual que passa dos 2.000mm de chuva/ano, caracterizando solos muito lixiviados e pobres quimicamente. Portanto, conclui-se que a relação das propriedades físicas e químicas avaliadas junto ao manejo inadequado ao longo dos anos tem apresentado um cenário de grandes dificuldades para a recuperação florestal na bacia hidrográfica do Córrego da Caçada, o que mostra a importância da avaliação dos impactos ambientais não só pelo recorte de bacias hidrográficas, como contextualizar seu posicionamento dentro de Unidades de Conservação, com legislações e objetivos específicos.