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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Sergipe no contexto da Segunda Guerra Mundial (1942) : uma abordagem da Arqueologia de ambientes aquáticos

Rosa, Roberta da Silva 31 August 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research aims to discuss critically about some aspects of the social context experienced in Sergipe, during the Second World War, through the analysis and interpretation of the material culture of that time. For this, we used as a theoretical and methodological approach, the approaches of Maritime Archeology and Historical Archeology, through which we investigated the tragic-naval episodes occurred with Brazilian merchant vessels - Baependy, Araraquara and Aníbal Benévolo - which were torpedoed and sunk by the German submarine U-507, in August 1942, between the coast of Sergipe and Bahia, that caused more than 500 deaths of men, women and children, and this event, one of the biggest reasons that led Brazil to declare a State of War throughout the country. / A presente pesquisa tem como objetivo discutir de maneira crítica sobre alguns aspectos do contexto social vivenciado em Sergipe, durante a Segunda Guerra Mundial, através da análise e interpretação de parte da cultura material da época. Para isso, utilizamos como aporte teórico-metodológico, as abordagens da Arqueologia de Ambientes Aquáticos e da Arqueologia Histórica, por meio das quais investigamos alguns episódios trágico-navais ocorridos com as embarcações mercantes brasileiras - Baependy, Araraquara e Aníbal Benévolo -, que foram torpedeadas e afundadas pelo submarino alemão U-507, em agosto de 1942, entre o litoral de Sergipe e da Bahia, e que provocou mais de 500 mortes entre homens, mulheres e crianças, sendo este acontecimento, um dos motivos maiores que levou o Brasil a declarar Estado de Guerra em todo território nacional.
12

Phylogenetic analysis of aquatic microbiomes : Evolution of the brackish microbiome

Deng, Ziling January 2020 (has links)
Microorganisms play crucial roles in aquatic environments in determining ecosystemstability and driving the turnover of elements essential to life. Understanding thedistribution and evolution of aquatic microorganisms will help us predict how aquaticecosystems will respond to Global Change, and such understanding can be gained bystudying these processes of the past. In this project, we investigate the evolutionaryrelationship between brackish water bacteria from the Baltic Sea and Caspian Seawith freshwater and marine bacteria, with the goal of understanding how brackishwater bacteria have evolved. 11,276 bacterial metagenome-assembled genomes(MAGs) from seven metagenomic datasets were used to conduct a comparativeanalysis of freshwater, brackish and marine bacteria. When clustering the genomes bypairwise average nucleotide identity (ANI) at the approximate species level (96.5%ANI), the Baltic Sea genomes were more likely to form clusters with the Caspian Seagenomes than with Swedish lakes genomes, even though geographic distancesbetween Swedish lakes and the Baltic Sea are much smaller. Phylogenomic analysisand ancestral state reconstruction showed that approximately half of the brackishMAGs had freshwater ancestors and half had marine ancestors. Phylogeneticdistances were on average shorter to freshwater ancestors, but when subsampling thetree to the same number of freshwater and marine MAG clusters, the distances werenot significantly different. Brackish genomes belonging to Acidimicrobiia,Actinobacteria and Cyanobacteriia tended to originate from freshwater bacteria, whilethose of Alphaproteobacteria and Bacteroidia mainly had evolved from marinebacteria. / Mikroorganismer spelar avgörande roller i akvatiska ekosystem där de driverkretsloppen av näringsämnen. En ökad förståelse för hur mikroorganismer anpassarsig till miljöförändringar är viktigt för att förutsäga hur akvatiska ekosystem kommeratt förändras som en konsekvens av global uppvärmning, och sådan förståelse kanuppnås genom att studera tidigare skeenden i evolutionen. I detta projekt undersökervi det evolutionära förhållandet mellan brackvatten-bakterier från Östersjön ochKaspiska havet med sötvattens- och marina bakterier, med målet att förstå hurbrackvatten-bakterier har utvecklats. 11,276 bakteriella arvsmassor somrekonstruerats med metagenomik från sju data-set användes för att utföra enjämförande analys av bakterie-genom från söt-, brack och havsvatten. Klustring avgenomen baserat på parvis genomsnittlig nukleotididentitet (ANI) på ungefärligartnivå (96,5% ANI), grupperade Östersjöns bakterier tillsammans med Kaspiskahavets bakterier mer än med bakterier från svenska sjöar, trots att det geografiskaavståndet mellan svenska sjöar och Östersjön är mycket mindre. Fylogenetisk analysvisade att ungefär hälften av brackvatten arterna hade anfäder från sötvatten ochhälften från havsvatten. De fylogenetiska avstånden var i genomsnitt kortare tillanfaderna i sötvatten, men när man reducerade trädet till att ha samma antal sötvattenoch marina arter var avstånden inte längre signifikant olika. Brackvatten-arter somtillhörde Acidimicrobiia, Actinobacteria och Cyanobacteriia tenderade att härstammafrån sötvattenbakterier, medan de från Alphaproteobacteria och Bacteroidia främsthärstammade från marina bakterier.
13

An SEM Study of Blastodinium Parasitism of Estuarine Calanoid Copepods: Impact on Mankind

Toma, Nicholas, Kunigelis, Stan C, PhD 07 April 2022 (has links)
Blastodinium, a genus of the phytoplanktonic dinoflagellates, was found to be inhabiting the gut region of the copepod species Labidocera. Copepods are ubiquitous in aquatic environments, being the most numerous multicellular organisms on planet earth. Being primary consumers, they play important ecological roles, passing energy from one trophic level to the next. As zooplankton, estuarine copepods contribute substantially to carbon cycling as they undergo diurnal migration to avoid daylight UV-B damage and surface water predation. Blastodinium are presumed to infect copepods via ingestion of zoospores by juvenile hosts, who function as microhabitats for acquiring nutrients in non-photosynthetic species or in nutrient-limited environments. Blastodinium may hinder reproduction of copepod hosts, thereby influencing local copepod populations and, by extension, food webs up to humanity. Copepod populations may also help contain disease spread, such as malaria and Dengue fever, through their consumption of mosquito larvae in standing water. Further evaluation of copepods for Blastodinium may help shed light on the limited knowledge of this species and the nature of its relationship with copepods, as well as its effects on copepod populations and the higher order consequences of its parasitism.

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