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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.
141

A case study of HIV/AIDS prevention in Nigeria : assessment and recommendations

Iyiani, Christian, n/a January 2008 (has links)
This is a two-stage study of HIV/AIDS prevention. In Stage One, the study examines the HIV/AIDS approach of Western aid organisations (INGOs) and compares it to the lived realities of people who are most 'at risk', sex workers, unemployed street youth, and married low income families, in the poor migrant community of Ajegunle in Nigeria�s Lagos state. The study found that INGOs and their client NGOs emphasised Western medical models of HIV/AIDS for both intervention (e.g. testing and ARV drugs for management) and prevention (e.g. through education and behaviour change). In contrast, among 'at-risk' groups, the study revealed a high degree of knowledge about the transmission of HIV/AIDS (contrary to Western medical assumptions), but also detected strong feelings of powerlessness in being able to address it. INGOs and their client organisations were operating at the levels of tertiary or curative and secondary or behaviour change prevention, whereas the views of the local 'at-risk people' indicated relevance of the primary prevention level, the social structural conditions of the people. In analysing the results of the first stage of the study, the findings identified a process of 'talking past each other' by official aid agencies and those most at risk, thereby inhibiting effective prevention. The INGOs and NGOs used their financial power, based on the gross inequality in the world distribution of resources, to dictate their own agendas, omitting primary intervention and instead concentrating on secondary and tertiary prevention. The study suggests that new thinking about multi-sectoral responses with full community participation is necessary in order to engage in more effective preventive action. The study then sought out alternative sources of power that might permit that to happen, notably the strengths of the local Ajegunle community. As a poor community, they lacked financial resources and human capital, such as skilled workers, but they had significant knowledge capital about their own circumstances and the realities people faced. The community also had considerable cultural capital and local organisations with considerable relational capital around community links, broad based support and commitment to such action. This analysis suggests the need to identify and work through the power differentials using community development processes, especially seeking to empower local communities to take part in decision-making over prevention, if effective action is to take place. The process required is one of a negotiated, inclusive partnerships for sharing information, experience, and decision-making, involving all the relevant stakeholders - the International Organisations (INGOs), National NGOs, Community Groups and the community itself.
142

De cada labrador un soldado y de cada agricultor un propietario

Barcos, María Fernanda 25 March 2010 (has links)
En la siguiente investigación analizamos uno de los aspectos menos conocidos de la historia rural bonaerense: los ejidos de los pueblos de campaña. Estos espacios se conformaron a medida que la colonización avanzaba, primero de manera espontánea y luego por iniciativa estatal, con el objetivo de asentar a los pobladores alrededor de los centros poblados y fomentar el cultivo. Así, a diferencia de otros espacios de colonización española, los ejidos constituyeron las áreas donde se establecieron los solares, las quintas y las chacras. La historiografía tradicional reparó muy poco en ellos y cuando lo hizo, fue desde una óptica que contraponía la primera parte del siglo XIX con la expansión posterior a Pavón. Dentro de esta lógica, los pueblos rurales fueron descriptos como espacios rudimentarios y sus habitantes casi no fueron tenidos en cuenta puesto que la mirada centrada en la "estancia" opacó cualquier interés sobre los labradores y pastores que habitaban en estos espacios. En contrapartida, el período posterior fue caracterizado como de despegue de la economía exportadora y desarrollo de las instituciones. Desde ese momento los poblados habrían cobrado nueva vida convirtiéndose en importantes núcleos de población incentivados por la llegada de la inmigración. Para desandar estos supuestos, estudiamos específicamente la historia del ejido de la Guardia de Luján (Mercedes) desde el momento en que se creó el fuerte hasta 1870. Cada uno de los capítulos se estructuró en torno a núcleos problemáticos generales que fueron abordados desde lo local: la propiedad, los labradores, el mercado de tierras, la estructura productiva y la construcción del estado. El estudio demuestra la imposibilidad de definir la estructura productiva de un partido completamente sin tener en cuenta a los ejidos puesto que se puede incurrir en generalizaciones erróneas. Además, el período abarcado y los temas seleccionados permitieron reconocer los cambios y continuidades que se produjeron en estos espacios durante la transición a la Argentina Moderna.
143

A case study of HIV/AIDS prevention in Nigeria : assessment and recommendations

Iyiani, Christian, n/a January 2008 (has links)
This is a two-stage study of HIV/AIDS prevention. In Stage One, the study examines the HIV/AIDS approach of Western aid organisations (INGOs) and compares it to the lived realities of people who are most 'at risk', sex workers, unemployed street youth, and married low income families, in the poor migrant community of Ajegunle in Nigeria�s Lagos state. The study found that INGOs and their client NGOs emphasised Western medical models of HIV/AIDS for both intervention (e.g. testing and ARV drugs for management) and prevention (e.g. through education and behaviour change). In contrast, among 'at-risk' groups, the study revealed a high degree of knowledge about the transmission of HIV/AIDS (contrary to Western medical assumptions), but also detected strong feelings of powerlessness in being able to address it. INGOs and their client organisations were operating at the levels of tertiary or curative and secondary or behaviour change prevention, whereas the views of the local 'at-risk people' indicated relevance of the primary prevention level, the social structural conditions of the people. In analysing the results of the first stage of the study, the findings identified a process of 'talking past each other' by official aid agencies and those most at risk, thereby inhibiting effective prevention. The INGOs and NGOs used their financial power, based on the gross inequality in the world distribution of resources, to dictate their own agendas, omitting primary intervention and instead concentrating on secondary and tertiary prevention. The study suggests that new thinking about multi-sectoral responses with full community participation is necessary in order to engage in more effective preventive action. The study then sought out alternative sources of power that might permit that to happen, notably the strengths of the local Ajegunle community. As a poor community, they lacked financial resources and human capital, such as skilled workers, but they had significant knowledge capital about their own circumstances and the realities people faced. The community also had considerable cultural capital and local organisations with considerable relational capital around community links, broad based support and commitment to such action. This analysis suggests the need to identify and work through the power differentials using community development processes, especially seeking to empower local communities to take part in decision-making over prevention, if effective action is to take place. The process required is one of a negotiated, inclusive partnerships for sharing information, experience, and decision-making, involving all the relevant stakeholders - the International Organisations (INGOs), National NGOs, Community Groups and the community itself.
144

Equipping a select group of married couples at Shepherdhill Baptist Church, Lagos, Nigeria, in communication skills to strengthen marriage relationships

Ayinde, Olatubosun Taiwo, January 2006 (has links)
Thesis (D. Min.)--New Orleans Baptist Theological Seminary, 2006. / Includes abstract and vita. Includes final project proposal. Includes bibliographical references (leaves 96-100, 51-52).
145

Equipping a select group of married couples at Shepherdhill Baptist Church, Lagos, Nigeria, in communication skills to strengthen marriage relationships

Ayinde, Olatubosun Taiwo, January 2006 (has links)
Thesis (D. Min.)--New Orleans Baptist Theological Seminary, 2006. / Includes abstract and vita. Includes final project proposal. Includes bibliographical references (leaves 96-100, 51-52).
146

Em defesa da liberdade: as experiências de um africano liberto entre Rio de Janeiro, Salvador e Lagos (1860 -1880)

Jesus, Cristiane Santos de 28 March 2016 (has links)
Submitted by Oliveira Santos Dilzaná (dilznana@yahoo.com.br) on 2016-03-28T15:03:07Z No. of bitstreams: 1 Dissertação Cristiane Santos de Jeusus.pdf: 1790019 bytes, checksum: 3073bd60eb74ee48d8a58488132fe3fc (MD5) / Approved for entry into archive by Ana Portela (anapoli@ufba.br) on 2016-03-28T18:46:25Z (GMT) No. of bitstreams: 1 Dissertação Cristiane Santos de Jeusus.pdf: 1790019 bytes, checksum: 3073bd60eb74ee48d8a58488132fe3fc (MD5) / Made available in DSpace on 2016-03-28T18:46:25Z (GMT). No. of bitstreams: 1 Dissertação Cristiane Santos de Jeusus.pdf: 1790019 bytes, checksum: 3073bd60eb74ee48d8a58488132fe3fc (MD5) / A pesquisa consiste no estudo de caso de Lúcio José Maria de Souza, um africano liberto que enfrenta a resistência das autoridades policiais baianas, quando de seu desembarque no porto da cidade do Salvador, em 1871, após estada de onze meses na cidade de Lagos, Nigéria (África). Documentos provenientes desse embate, produzidos pelo consulado inglês e polícia do porto – atualmente, sob salvaguarda do Arquivo Público da Bahia – fornecem dados que permitem vislumbrar um panorama da intensa circulação de africanos libertos entre Salvador e a costa ocidental do continente africano. Através da abordagem micro histórica e do método indiciário de investigação, analisam-se as estratégias e mecanismos utilizados por aquele africano em defesa de sua liberdade, revelando um fluxo de pessoas que instaura uma importante conexão entre cidades do império brasileiro – Rio de Janeiro, Recife e Salvador – e o Oeste da África (Lagos, Uidá, Badagry e outras). Nesse contexto, a presente pesquisa destaca de que modo às experiências vividas por Lúcio José Maria de Souza se inserem no cenário das rotas comerciais, religiosas e afetivas que conectavam o Mundo Atlântico.La recherche concerne l’étude de cas de Lúcio José Maria de Souza, unAfricainlibéréquiaffrontelarésistencedesautoritéspolicièresbahianaises, lors de sondébarquementauport de lavilledu Salvador, en 1871, aprèsunséjour d’onze mois à laville de Lagos, Nigéria (Afrique). Des documentsprovenant de cetteconfrontation, produits par leconsulatanglais et lapoliceduport – actuellementsouslasauvegardedesArchives Publiques de Bahia – fournissentdesdonnéesquipermettent de percevoirun panorama de l’intensecirculation d’esclaveslibérés entre Salvador et lacôteoccidentaleducontinentafricain. Par lemoyen de l’approche micro historique et de laméthodeindiciaire de recherche, onanalyselesstratégies et lesmécanismesutilisés par cetAfricain à fin de défendresaliberté, tout enrévélantun flux de personnesquiétablit une liaison importante entre quelquesvilles de l’empirebrésilien – Rio de Janeiro, Recife et Salvador – et l’Ouest de l’Afrique (Lagos, Uidá, Badagryparmi d’autres). Danscecontexte, cetteétudemetenévidencelamanièredontlesexpériencesvécues par Lúcio José Maria de Souza s’insèrentdanslecadredesroutescommerciales, réligieuses et affectivesquireliaientle Monde Atlantique.
147

Estudo limnológico da Lagoa dos Tropeiros, Capitólio, MG, com ênfase na comunidade de macroinvertebrados bentônicos / Limnological study of tropeiros lake, Capitólio, MG, with emphasis on benthic macroinvertebrates community

França, Roberta Sebastiany 26 February 2010 (has links)
Made available in DSpace on 2016-06-02T19:29:21Z (GMT). No. of bitstreams: 1 2880.pdf: 4933136 bytes, checksum: 04da1395a352e195207e8a79539aeb19 (MD5) Previous issue date: 2010-02-26 / Financiadora de Estudos e Projetos / The studies on the diversity and functional role of benthic macroinvertebrates in lake ecosystems can provide relevant informations regarding the functioning and the health of these freshwater ecosystems. The aim of this study was to analyze the Tropeiros Lake, located in the municipality of Capitólio (MG), performing a limnological evaluation of the ecosystem and ecological investigation on the diversity of the benthic macroinvertebrate community. Thus, changes in the taxonomical composition, abundance, diversity, biomass and the taxa participation in the trophic functional groups were analyzed. Water and sediment were sampled in October 2006 and 2007 (dry periods) and in March 2007 and 2008 (rainy periods). The results evidenced that Tropeiros Lake is a shallow environment with maximum depth of 3 m, densely colonized by macrophytes and with high water transparency. It has low concentration of nitrogen with predominance of the ammonium ion, low concentrations of phosphorus being organic phosphate the predominant compound, low pH values with water varying from neutral to slightly acid and moderate water electrical conductivity. The sediment has high clay and organic matter contents. The Discriminant Analysis separated the sampling periods, grouping the similar rainy periods but separating the dry ones. According to the trophic state index the lake was classified as oligotrophic during the rainy periods and mesotrophic during the dry periods. Benthic community was composed by 81 taxa, mainly represented by the members of the Order Diptera, especially those belonging to the families Chironomidae and Chaoboridae. The trophic guild of collectors was the most representative, with minimum abundance of 57.2%, with the taxa Chironomus sp, Goeldichironomus sp and Tanytarsus sp, followed by that of the predators, having Chaoborus and Ablabesmyia sp as the main taxa. The mean biomass determined for the macroinvertebrate community of Tropeiros Lake was 0.94 g. m-2. Except Chironomus sp, that was abundant, regarding both, numbers and biomass, a different condition was observed for the taxa as Pisidium pulchellum, Melanoides tuberculata and a Libellulidae nymph that were numerically less abundant but contributed significantly for the total biomass. Regarding the trophic guilds, predators was more representative in the periods of October 2006 and March 2007 than the collector guild, in terms of biomass. The same was observed regarding the macroinvertebrates contribution to the biomass in each trophic guild, where predators were more abundant than collectors in October 2006 and March 2007, evidencing the importance of this approach in ecological studies. The method based on K-dominance curves (ABC curves) indicated that Tropeiros Lake is under moderate perturbation according to the cumulative values of abundance and biomass. This results corroborates those obtained for lake trophic state index, based on the mean biomass when compared to environments of different trophic states and with the species composition, formed by both, group of tolerant species as well as those more sensible to adverse environmental conditions. / A diversidade e o papel funcional dos táxons que compõem a comunidade de macroinvertebrados bentônicos dos sistemas lacustres podem fornecer informações importantes sobre a saúde e funcionamento destes ecossistemas de água doce. O objetivo deste estudo foi analisar limnologicamente a Lagoa dos Tropeiros, em Capitólio (MG), e realizar um estudo ecológico da diversidade dos macroinvertebrados bentônicos, avaliando a densidade, abundância, biomassa e participação dos táxons nas guildas tróficas funcionais. Para isso foram avaliadas as mudanças na composição taxonômica, na diversidade e na ocorrência sazonal da comunidade bentônica desse sistema. As amostras de água e de sedimento foram coletadas em outubro de 2006 e de 2007 (períodos secos) e em março de 2007 e de 2008 (períodos chuvosos). Os resultados indicaram que a lagoa caracterizou-se como sendo um ambiente raso, com profundidade máxima de 3m, grande quantidade de macrófitas aquáticas, elevada transparência da água, reduzidas concentrações de compostos de nitrogênio, com predominância do íon amônio, e baixas concentrações de fósforo com predomínio de fosfato orgânico, valores de pH variando de neutros a ligeiramente ácidos, condutividade moderada e elevados teores de argila e de matéria orgânica no sedimento. A Análise Discriminante evidenciou a separação dos períodos de amostragem, sendo que os períodos chuvosos foram muito semelhantes, diferentemente do observado para os períodos secos que se diferenciaram por diferentes características ambientais. De acordo com o Índice de Estado Trófico a lagoa foi classificada como um ambiente oligotrófico durante os períodos chuvosos e mesotrófico durante os períodos de seca. A comunidade bentônica foi composta por 81 táxons, sendo representada principalmente por organismos pertencentes à ordem Diptera, especialmente das famílias Chironomidae e Chaoboridae. A guilda trófica dos coletores foi a mais representativa, com abundância mínima de 57,2%, sendo os principais representantes os táxons Chironomus sp, Goeldichironomus sp e Tanytarsus sp, seguida pelos predadores com Chaoborus sp e Ablabesmyia sp como os principais táxons. A biomassa média calculada para a comunidade de invertebrados bentônicos na lagoa foi de 0,94 g. m-2. Com exceção de Chironomus sp, que foi abundante em termos de número de indivíduos e também de biomassa, observou-se uma condição diferente para táxons como Pisidium pulchellum, Melanoides tuberculata e uma ninfa de Libellulidae os quais foram pouco abundantes numericamente, mas apresentaram uma elevada participação na composição da biomassa total. O mesmo foi observado para a participação dos macroinvertebrados em biomassa nas guildas tróficas, onde os predadores foram mais abundantes que os coletores em outubro de 2006 e março de 2007, demonstrando a importância dessa abordagem em estudos ecológicos. O método baseado em curvas de k-dominância (curvas ABC) indicou que a Lagoa dos Tropeiros encontra-se moderadamente perturbada, de acordo com os valores cumulativos de abundância de indivíduos e biomassa. Tal resultado confirma aqueles obtidos para o índice de estado trófico, para os valores de biomassa média quando comparados com ambientes de diferentes graus de trofia e com a composição das espécies presentes, formada tanto por grupos tolerantes como também por aqueles mais sensíveis às condições ambientais adversas.
148

Limnologia de lagos de várzea do rio Madeira com ênfase na diversidade e produção secundária da comunidade zooplanctônica

Negreiros, Natalia Felix 06 March 2014 (has links)
Made available in DSpace on 2016-06-02T19:30:01Z (GMT). No. of bitstreams: 1 5864.pdf: 3534463 bytes, checksum: cd15fcfba13c323323c9b239d2f29ed8 (MD5) Previous issue date: 2014-03-06 / Financiadora de Estudos e Projetos / The study of diversity and productivity can contribute to understanding the functioning of Amazonian ecosystems as a whole and especially to the conservation of its aquatic biota, considered one of the richest in species on the planet. The present study aimed to analyze the course of three years the limnological characteristics of three floodplain lakes of the Madeira River in the area of influence of the Santo Antônio hydroelectric plant on the Madeira, in the region near to Porto Velho, Rondônia, with emphasis on the zooplankton community. Samples were quarterly covering the four major hydrological periods: low water, flood, high water and ebb over three years (2010-2013). Physical, chemical and biological variables of the lakes were collected and correlated with species composition, biomass and production of zooplankton. The zooplankton community was characterized by high species richness (195 taxa) and high degree of endemism for the group of Copepoda Calanoida. The results showed that the three lakes have eutrophic or mesotrophic characteristics. The highest values of density and biomass of zooplankton in the lake occurred Cujubim. The rotifers were numerically dominant, but the Copepoda dominated in biomass and secondary production in lakes Cuniã and San Miguel. There was little variability in secondary production of zooplankton, being slightly higher in the lake Cujubim with increased production of copepods and rotifers in this lake. The rainfall variation demarcated the occurrence of well-defined hydrological periods, directly affecting the hydrodynamics of this region, controlling population fluctuations of zooplankton, probably brought by the increased availability of resources on the Madeira River in the flood season, playing an important role in the organization of food webs, and how to link the transfer of matter and energy in food chains. / O estudo da diversidade e produtividade pode contribuir para o entendimento do funcionamento dos ecossistemas amazônicos como um todo e principalmente para a conservação da sua biota aquática, considerada uma das mais ricas em espécies no planeta. O presente estudo teve como objetivo analisar ao longo de três anos as características limnológicas de três lagos de várzea do rio Madeira na área de influência da Usina Hidroelétrica Santo Antônio do Madeira, na região próxima a Porto Velho, Rondônia, com ênfase na comunidade zooplanctônica. As amostragens foram trimestrais abrangendo os quatro períodos hidrológicos principais: Águas baixas, enchente, águas altas e vazante, ao longo de três anos (2010-2013). Foram coletadas variáveis físicas, químicas e biológicas dos lagos, correlacionando com a composição de espécies, além de determinadas a biomassa e a produção da comunidade zooplanctônica. A comunidade zooplanctônica foi caracterizada por elevada riqueza de espécies (195 táxons) e alto grau de endemismo para o grupo dos Copepoda Calanoida. Os resultados obtidos evidenciaram que os três lagos apresentam características mesotróficas ou eutróficas. Os maiores valores de densidade e biomassa da comunidade zooplanctônica ocorreram no lago Cujubim. Os Rotifera foram numericamente dominantes, mas os Copepoda dominaram em biomassa e produção secundária, nos lagos Cuniã e São Miguel. Houve pequena variabilidade na produção secundária da comunidade zooplanctônica, sendo ligeiramente superior no lago Cujubim, com maior a produção de Copepoda e Rotifera neste lago. A variação pluviométrica demarcou a ocorrência de períodos hidrológicos bem definidos, afetando diretamente a hidrodinâmica desta região, controlando flutuações populacionais da comunidade zooplanctônica, provavelmente pela maior disponibilidade de recursos trazidos do rio Madeira nos períodos de cheia, desempenhando papel importante na organização das teias tróficas, e como elo de transferência de matéria e energia nas cadeias alimentares.
149

O impacto da remo??o de peixes sobre a din?mica e estrutura dos grupos funcionais fitoplanct?nicos em um lago raso tropical durante uma seca severa

Costa, Mariana Rodrigues Amaral da 20 March 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-15T23:04:38Z No. of bitstreams: 1 MarianaRodriguesAmaralDaCosta_DISSERT.pdf: 2488995 bytes, checksum: c1bb8bd3c6d969c70744bfd049bfdd73 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-20T21:52:13Z (GMT) No. of bitstreams: 1 MarianaRodriguesAmaralDaCosta_DISSERT.pdf: 2488995 bytes, checksum: c1bb8bd3c6d969c70744bfd049bfdd73 (MD5) / Made available in DSpace on 2016-04-20T21:52:13Z (GMT). No. of bitstreams: 1 MarianaRodriguesAmaralDaCosta_DISSERT.pdf: 2488995 bytes, checksum: c1bb8bd3c6d969c70744bfd049bfdd73 (MD5) Previous issue date: 2014-03-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A eutrofiza??o artificial ? uma das grandes amea?as ? qualidade ambiental de ecossistemas aqu?ticos em todo o mundo. As expectativas dos cen?rios clim?ticos futuros para regi?es ?ridas e semi?ridas s?o per?odos de secas mais intensas e frequentes, aumentando ainda mais o risco de eutrofiza??o e de flora??es de cianobact?rias. Muitas t?cnicas de restaura??o de lagos eutrofizados foram propostas para reduzir as cargas de nutrientes e melhorar a qualidade da ?gua. Uma t?cnica bastante utilizada ? a biomanipula??o por remo??o de peixes que v?m se mostrando eficiente em lagos eutr?ficos de regi?es temperadas. Trabalha mos a hip?tese de que a remo??o de peixes bent?v oros bioturbadores reduz a biomassa total do fitopl?ncton e altera a composi??o dos grupos funcionais fitoplanct?nicos , refletindo na melhora d a qualidade da ?gua . Assim , este estudo teve como objetivo avaliar o impacto da biomanipula??o na din?mica e estr utura d os grupos funcionais fitoplanct?nicos e n a qualidade da ?gua. Aplicamos a t?cnica da biomanipula??o no lago artificial ESEC, regi?o semi?rida do nordeste brasileiro e analisamos as vari?veis f?sicas e qu?micas da ?gua e a din?mica dos grupos funcion ais fitoplanct?nicos, mensalmente durante o per?odo de novembro de 2012 a agosto de 2013. Com a remo??o dos peixes bioturbadores, observamos um aumento significativo na zona euf?tica, na riqueza de esp?cies fitoplanct?nicas e o recrutamento de grupos funci onais fitoplanct?nicos de algas verdes (grupos F e J) indicadoras de boa qualidade ambiental. Por?m, n?o observamos diferen?as significativas na concentra??o de f?sforo total e na biomassa e diversidade fitoplanct?nica. O efeito da seca severa na regi?o du rante o estudo foi evidente , proporcionando uma redu??o dr?stica no n?vel de ?gua que influenciou na disponibilidade de recursos e afetou a comunidade fitoplanct?nica antes da biomanipula??o . Para avaliar o efeito de uma seca severa sobre a din?mica dos gr upos funcionais fitoplanct?nicos e testar se per?odos de seca s?o favor?veis ? domin?ncia de cianobact?rias, estudamos dois lagos artificiais vizinhos (ESEC e Pocinhos) no semi?rido tropical durante maio de 2012 a fevereiro de 2013. Observamos uma diferenc ia??o temporal das vari?veis abi?ticas e do fitopl?ncton causada pela seca severa. Ambos os lagos apresentaram redu??o de 2 metros do n?vel da ?gua e aumento nos valores de condutividade, turbidez, nas concentra??es de nutrientes e redu??o da transpar?ncia da ?gua, durante o per?odo da seca severa. Por?m, a comunidade fitoplanct?nica respondeu diferente ?s condi??es ambientais dependendo da profundidade de cada lago. O mais profundo (Pocinhos) aumentou a biomassa total do fitopl?ncton e apresentou domin?nci a do grupo funcional de cianobact?rias heterocitadas formadoras de flora??o (grupo S N ) e o lago menos profundo (ESEC) reduziu a biomassa total e apresentou domin?ncia de grupos funcionais de algas flageladas com metabolismo mixotr?fico (grupos W 1 e W 2 ) . Su marizando, o conhecimento sobre os efeitos da biomanipula??o por remo??o de peixes bent?voros bioturbadores em um lago raso no semi?rido tropical ainda ? incipiente e o estudo possui limita??es devido ao evento de seca prolongada durante o per?odo de estud o . Sendo assim, ? necess?rio um monitoramento em longo prazo para investigar os reais efeitos da biomanipula??o no funcionamento do ecossistema. Al?m disso, per?odos de seca podem ter efeitos antag?nicos (aumento ou redu??o) na biomassa total , bem como na composi??o dos grupos funcionais fitoplanct?nicos, que nem sempre levar? ? domin?ncia de cianobact?rias. / The artifi cial eutrophication is one of the biggest t h reat for the quality of aquatic ecosystems in the whole world. The expectations for the future climatic scenarios in arid and semi - arid regions are intense and frequent droughts enhancing the risk of eutrophicati on and cyanobacterial blooms. Restoration techniques of eutrophic lakes were proposed to reduce nutrient loading and improve the water quality. A successful technique used in temperate regions is the biomanipulation by benthivorous fish removal . Our hypoth esis is that the benthivorous fish removal reduces phytoplankton total biomass and change the composition of phytoplankton functional groups, improving water quality. The aim of the study was evaluate the impact of biomanipulation on phytoplankton function al groups and in the water quality. We applied the technique of biomanipulation in the artificial lake ESEC, in a semi - arid region of Brazil and analyzed the physical and chemical variables and the dynamic of phytoplankton functional groups monthly during November 2012 to August 2013. With the removal of benthivorous fish we observed a significant increase of the euphotic depth, phytoplankton richness and the recruitment of green algae (groups F and J ), indicators of good water quality. However, we did not observe significant differences on total phosphorous concentration and on phytoplankton biomass and diversity. The drought effect in the region during the study was evident , promoting a drastic reduction on water level which influenced the availability of resource and affected phytoplankton community before the biomanipulation. To evaluate the effect of severe drought on the dynamic of phytoplankton functional groups and test if the drought periods are favorable to dominance of cyanobacterial groups, we stu died two artificial neighbors lakes (ESEC and Pocinhos) in a semi - arid tropical region during May 2012 to February 2013. We observed a temporal differentiation of biotic and abiotic variables caused by drought. Both lakes presented reduction of 2 meters of water level and increase on conductivity, turbidity, nutrients concentration and a reduction on water transparency, during the severe drought. The deeper lake (Pocinhos) increased phytoplankton total biomass and presented cyanobacterial functional group d ominance (group S N ) and the shallower lake (ESEC) reduced phytoplankton total biomass and presented dominance of mixotrophic and flagellate functional groups (groups W 1 e W 2 ). Summarizing, the knowledge of the effects of benthivorous fish removal in semi - a rid tropical lakes still unknown and this study had limitations caused by the impact of drought. Thus, it is necessary a long term monitoring to investigate the real effects of biomanipulation on the functioning of the studied ecosystems. Otherwise, period s of drought could have opposite effects (increase or reduction) on total biomass and composition of phytoplankton functional groups. Drought not always leads to dominance of cyanobacterial groups.
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Adi??o de policloreto de alum?nio e remo??o de peixes bent?voros como t?cnicas de restaura??o de lagos rasos do semi?rido brasileiro

Silva, Fabiana Oliveira de Ara?jo 03 February 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-06T20:31:23Z No. of bitstreams: 1 FabianaOliveiraDeAraujoSilva_TESE.pdf: 783632 bytes, checksum: d5a28b9c131a2a8187ccb70b95821d14 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-08T17:34:29Z (GMT) No. of bitstreams: 1 FabianaOliveiraDeAraujoSilva_TESE.pdf: 783632 bytes, checksum: d5a28b9c131a2a8187ccb70b95821d14 (MD5) / Made available in DSpace on 2016-07-08T17:34:29Z (GMT). No. of bitstreams: 1 FabianaOliveiraDeAraujoSilva_TESE.pdf: 783632 bytes, checksum: d5a28b9c131a2a8187ccb70b95821d14 (MD5) Previous issue date: 2015-02-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / A eutrofiza??o ? a causa mais comum de deteriora??o da qualidade da ?gua no mundo. Este processo se d? pela entrada excessiva de nutrientes, nitrog?nio e f?sforo, nos corpos aqu?ticos causando flora??es de algas e cianobact?rias. Em lagos rasos esses efeitos s?o mais complicados devido a uma maior intera??o do corpo aqu?tico com o entorno, com o ar e o sedimento. Existem v?rias t?cnicas de restaura??o de lagos eutrofizados, com uma vasta gama de resultados bem sucedidos, mas no Brasil h? apenas um ?nico caso de restaura??o bem sucedida: o lago Parano? em Bras?lia. A regi?o semi?rida brasileira possui milhares de lagos artificiais, regionalmente chamados de a?udes, em sua maioria rasos e eutr?ficos. A eutrofiza??o desses corpos aqu?ticos ? documentada e o fitopl?ncton desses ambientes ? frequentemente dominado por cianobact?rias potencialmente t?xicas. O principal objetivo desta tese de doutorado ? testar diferentes t?cnicas de restaura??o da qualidade da ?gua que possam ser facilmente aplicadas em lagos rasos do semi?rido brasileiro. Resultados de um experimento em laborat?rio sugerem que a aplica??o de argila adsorvente de f?sforo associada a um coagulante ? base de alum?nio ? uma t?cnica efetiva na remo??o do f?sforo reativo sol?vel e na diminui??o da taxa de crescimento da Cylindrospermopsis raciborskii, cianobact?ria potencialmente t?xica que domina nos reservat?rios do semi?rido brasileiro, mas que esse efeito ? dependente da biomassa no momento da aplica??o da t?cnica. Os resultados de um experimento de campo realizado em mesocosmos num lago raso eutrofizado demonstraram que a aplica??o de coagulante ? base de alumn?nio em conjunto com a da remo??o de peixes bent?voros ? mais eficiente na remo??o de f?sforo total e clorofila-a da coluna de ?gua do que a aplica??o isolada de apenas uma dessas t?cnicas. Por fim, testes de laborat?rio demostraram que o coagulante ? base de alum?nio apresentou um bom desempenho em remover turbidez e f?sforo total em testes de bancada com ?gua de seis reservat?rios do semi?rido, sendo a efici?ncia reduzida com o aumento da biomassa de clorofila e pH. Os resultados deste estudo mostram que ? poss?vel melhorar a qualidade da ?gua de reservat?rios eutrofizados no semi?rido brasileiro atrav?s do controle da carga interna de nutrientes seja pela precipita??o e inativa??o do f?sforo no sedimento, como tamb?m pela inibi??o da libera??o do f?sforo no sedimento por peixes bioturbadores, e que os resultados s?o aditivos quando as t?cnicas s?o aplicadas em conjunto. / Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Parano? Lake in Bras?lia city. The Brazilian semiarid region has many artificial lakes, named a?udes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate ? cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid ? but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.

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