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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.
31

Estudo de associações entre o gene PER3 e a sincronização de ritmos circadianos pelo claro/escuro / Study of association between PER3 gene and circadian rhythms synchronization to light/dark]

Pereira, Danyella Silva [UNIFESP] 28 September 2011 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:50:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-09-28. Added 1 bitstream(s) on 2015-08-11T03:26:14Z : No. of bitstreams: 1 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:14Z : No. of bitstreams: 2 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5) Publico-12928b.pdf: 1880217 bytes, checksum: 6648abaf82f0acd825d3dcf9d25f4b07 (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:14Z : No. of bitstreams: 3 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5) Publico-12928b.pdf: 1880217 bytes, checksum: 6648abaf82f0acd825d3dcf9d25f4b07 (MD5) Publico-12928c.pdf: 1411727 bytes, checksum: 904935188925dceb52a7097df537522d (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:14Z : No. of bitstreams: 4 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5) Publico-12928b.pdf: 1880217 bytes, checksum: 6648abaf82f0acd825d3dcf9d25f4b07 (MD5) Publico-12928c.pdf: 1411727 bytes, checksum: 904935188925dceb52a7097df537522d (MD5) Publico-12928d.pdf: 1530766 bytes, checksum: fd42298f053da9b0b24eef36db4b9c2d (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:14Z : No. of bitstreams: 5 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5) Publico-12928b.pdf: 1880217 bytes, checksum: 6648abaf82f0acd825d3dcf9d25f4b07 (MD5) Publico-12928c.pdf: 1411727 bytes, checksum: 904935188925dceb52a7097df537522d (MD5) Publico-12928d.pdf: 1530766 bytes, checksum: fd42298f053da9b0b24eef36db4b9c2d (MD5) Publico-12928e.pdf: 1829757 bytes, checksum: 3ebbd3100e4ba4e752ade51bb28b8af5 (MD5). 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Added 1 bitstream(s) on 2015-08-11T03:26:15Z : No. of bitstreams: 8 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5) Publico-12928b.pdf: 1880217 bytes, checksum: 6648abaf82f0acd825d3dcf9d25f4b07 (MD5) Publico-12928c.pdf: 1411727 bytes, checksum: 904935188925dceb52a7097df537522d (MD5) Publico-12928d.pdf: 1530766 bytes, checksum: fd42298f053da9b0b24eef36db4b9c2d (MD5) Publico-12928e.pdf: 1829757 bytes, checksum: 3ebbd3100e4ba4e752ade51bb28b8af5 (MD5) Publico-12928f.pdf: 2021777 bytes, checksum: 63f4cd02d7bbbcbba66e14684b70d86a (MD5) Publico-12928g.pdf: 1989001 bytes, checksum: ab8b7e8b8b3a00cf39a9dd8112fe7885 (MD5) Publico-12928h.pdf: 1973579 bytes, checksum: dae2b81265b61957bc28aac9f5a10857 (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:15Z : No. of bitstreams: 9 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5) Publico-12928b.pdf: 1880217 bytes, checksum: 6648abaf82f0acd825d3dcf9d25f4b07 (MD5) Publico-12928c.pdf: 1411727 bytes, checksum: 904935188925dceb52a7097df537522d (MD5) Publico-12928d.pdf: 1530766 bytes, checksum: fd42298f053da9b0b24eef36db4b9c2d (MD5) Publico-12928e.pdf: 1829757 bytes, checksum: 3ebbd3100e4ba4e752ade51bb28b8af5 (MD5) Publico-12928f.pdf: 2021777 bytes, checksum: 63f4cd02d7bbbcbba66e14684b70d86a (MD5) Publico-12928g.pdf: 1989001 bytes, checksum: ab8b7e8b8b3a00cf39a9dd8112fe7885 (MD5) Publico-12928h.pdf: 1973579 bytes, checksum: dae2b81265b61957bc28aac9f5a10857 (MD5) Publico-12928i.pdf: 1974866 bytes, checksum: 8527e8ec136a64da7ca5923c045bb127 (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:15Z : No. of bitstreams: 10 Publico-12928a.pdf: 1350312 bytes, checksum: a1b87661651bcb379be01ed1780b6311 (MD5) Publico-12928b.pdf: 1880217 bytes, checksum: 6648abaf82f0acd825d3dcf9d25f4b07 (MD5) Publico-12928c.pdf: 1411727 bytes, checksum: 904935188925dceb52a7097df537522d (MD5) Publico-12928d.pdf: 1530766 bytes, checksum: fd42298f053da9b0b24eef36db4b9c2d (MD5) Publico-12928e.pdf: 1829757 bytes, checksum: 3ebbd3100e4ba4e752ade51bb28b8af5 (MD5) Publico-12928f.pdf: 2021777 bytes, checksum: 63f4cd02d7bbbcbba66e14684b70d86a (MD5) Publico-12928g.pdf: 1989001 bytes, checksum: ab8b7e8b8b3a00cf39a9dd8112fe7885 (MD5) Publico-12928h.pdf: 1973579 bytes, checksum: dae2b81265b61957bc28aac9f5a10857 (MD5) Publico-12928i.pdf: 1974866 bytes, checksum: 8527e8ec136a64da7ca5923c045bb127 (MD5) Publico-12928j.pdf: 1928961 bytes, checksum: bfccdba529b27f5fabe99133543b72bf (MD5) / O gene Per3 está envolvido na regulação de mecanismos de temporização circadiana. Sua real função ainda não está totalmente elucidada. Algumas hipóteses atuais nos levam a crer que este gene tenha algum papel no mecanismo de sincronização ao estímulo luminoso em ciclos claro/escuro. O principal objetivo deste trabalho foi investigar as possíveis associações entre o gene Per3 e a regulação da ritmicidade circadiana dependente da duração da fotofase. A parte experimental foi dividida em duas etapas: 1. Trabalhamos com camundongos knockout para o gene (Per3-/-) e avaliamos os possíveis mecanismos pelos quais o gene poderia estar envolvido na adaptação e duração da fotofase, expondo esses animais a regimes de claro/escuro diferenciados de forma que houvesse fotofases muito curtas ou longas. 2. Foi feito um experimento em humanos, em duas localidades (Natal e São Paulo) situadas em diferentes latitudes (05°47’S e 23°32’S, respectivamente). O protocolo experimental foi realizado em estações do ano diferentes de forma que pudéssemos mimetizar a variação de fotofase usada em condições laboratoriais. O experimento em humanos foi feito com o intuito de verificar se as inferências feitas a partir do modelo animal eram de alguma forma aplicáveis. Sugerimos a partir dos resultados obtidos na primeira fase do estudo que os animais Per3-/- sejam menos sensíveis ao mascaramento à luz e os resultados da segunda etapa mostram, um atraso nas fases das variáveis circadianas analisadas (início e final da atividade, meia fase de M10 da atividade e meia fase de M6 da temperatura) em Natal, principalmente no grupo de indivíduos do genótipo PER35/5 durante o mês de novembro. De maneira geral, os dados nos camundongos apontam um caminho relacionado com estudos de mascaramento à luz para elucidação da função do gene e os dados em humanos mostram que é possível associá-lo aos ajustes de fase derivados de características específicas do ciclo claro/escuro dados por diferentes latitudes. / Per3 gene is a component of the circadian molecular mechanism. Its function is not completely understood. One of the hypotheses is that Per3 gene may be involved in light synchronization mechanism. The aim of this project was investigate the association between Per3 gene and circadian rhythmicity dependent of the photophase duration in different light/dark cycle regimens. The experimental protocol was divided in two parts: 1. We investigated the possible mechanisms of association between Per3 gene and adaptation/duration of the photophase in Per3-/- mice by exposing the animals to different light/dark cycles with long or short photophases 2. Based on the results of experiment 1, we developed an experiment in humans in order to investigate if the results in mice were someway applicable to our population. Subjects from two locations with different latitudes were selected (Natal and São Paulo) and the experiment was carried out in two different seasons of the year to mimic photophase variation. The first part of our results suggested that Per3 gene is associated with sensitivity of masking by light. In the second part of the study, we found a phase delay in the circadian parameters analyzed (beginning and end of activity, markers of activity (M10) and temperature (M6)) in the PER35/5 group from Natal on November, when compared to the São Paulo group. Our data in mice point out a new hypothesis related to masking effect that may contribute to the understanding of Per3 gene function in the regulation of circadian rhythms and the human data show that it is possible to associate Per3 gene with the phase adjustments derived from specific characteristics of light/dark cycle in different latitudes. / TEDE / BV UNIFESP: Teses e dissertações
32

Efeitos espaço temporais da poluição pontual e não pontual em uma bacia hidrográfica subtropical : ecohidrologia como ferramenta de controle

Gatti Junior, Pedro 27 July 2015 (has links)
Submitted by Daniele Amaral (daniee_ni@hotmail.com) on 2016-09-14T20:55:19Z No. of bitstreams: 1 TesePGJ.pdf: 2065946 bytes, checksum: 88cecd364b6c5b24ea99e24abd33e1d9 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-16T19:46:32Z (GMT) No. of bitstreams: 1 TesePGJ.pdf: 2065946 bytes, checksum: 88cecd364b6c5b24ea99e24abd33e1d9 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-16T19:46:40Z (GMT) No. of bitstreams: 1 TesePGJ.pdf: 2065946 bytes, checksum: 88cecd364b6c5b24ea99e24abd33e1d9 (MD5) / Made available in DSpace on 2016-09-16T19:46:47Z (GMT). No. of bitstreams: 1 TesePGJ.pdf: 2065946 bytes, checksum: 88cecd364b6c5b24ea99e24abd33e1d9 (MD5) Previous issue date: 2015-07-27 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Contaminants are introduced into aquatic ecosystems, both from point and diffuse sources and usually are deposited in the sediments of lakes and reservoirs. The input of diffuse pollutants in the environment is of difficult control and identification, while the control of point sources is more efficient because they are easily identified. However, the frequent discharges of effluents, althought undergoing treatment, may change the input of elements and substances in a given region. The aim of this study was to assess the spatial-temporal influence of point and non-point source pollution on the characteristics of surface water and sediment in a watershed with well-marked seasons. In addition, concepts and attempts at ecosystems restoration in different regions were reviewed in order to understand the main drivers of abiotic-biotic regulation among watersheds and aquatic ecosystems, based on the principles of Ecohydrology. For this purpose, the concentrations of Cd, Cr, Fe, Ni, Zn, Pb, Al, Cu, Mn, Hg, As, Se, total phosphorus, total nitrogen and ions in water and sediment were examined. Furthermore, levels of metals (Al, Fe, Mn, Cu, Zn, Hg and As) in the sediment profile of stations under of the influence of different impact were evaluated. This study showed that the point source pollution promote a high load of contaminants in sediment, regardless of the season. Furthermore, the point pollution sources seem to be spatially and temporally the main cause of reservoir sediment chemical composition due its frequent effluent release. This study also indicates that, despite several biogeographical differences, hydrology seems to be the main factor that controls the primary and secondary production and sustainability in rivers and lakes (reservoirs). In conclusion, the hydrology in the tropics seems to decrease the expected effects of a higher temperature. Therefore, to increase resilience in tropical freshwaters integrated actions according to hydrological stages are highly recommended. / Contaminantes são introduzidos em ecossistemas aquáticos, a partir de fontes pontuais e difusas e geralmente são depositados nos sedimentos de lagos e reservatórios. A entrada de poluentes difusos no ambiente é de difícil controle e identificação, enquanto que o controle de fontes pontuais é mais eficiente, pois são facilmente identificados. No entanto, as frequentes descargas de efluentes, mesmo passando por tratamento, podem mudar a dinâmica de entrada de elementos e substâncias em uma região. O objetivo deste estudo foi avaliar a influência espaço-temporal de fontes de poluição pontual e não pontual nas características das águas superficiais e do sedimento de um reservatório (Lobo/Broa, SP) em uma bacia hidrográfica com estações climáticas bem definidas. Além disso, conceitos e tentativas de restauração em diferentes ecossistemas foram revisados com o objetivo de entender quais são os principais controladores da regulação abiótica-biótica entre bacias hidrográficas e ecossistemas aquáticos, com base nos princípios da Ecohidrologia. Para este propósito, as concentrações de Cd, Cr, Fe, Ni, Zn, Pb, Al, Cu, Mn, Hg, As, Se, fósforo total, nitrogênio total e íons na água e no sedimento foram examinadas. Além disso, os níveis de metais (Al, Fe, Mn, Cu, Zn, Hg e As) no perfil do sedimento de pontos amostrais sob influência de diferentes impactos foram avaliados. Este estudo mostrou que as fontes pontuais de poluição promovem uma alta carga de contaminantes nos sedimentos, independentemente da estação. Além disso, as fontes de poluição pontual parecem ser espacialmente e temporalmente as principais causa da composição química de sedimentos do reservatório por causa da frequente liberação de efluentes. Esse estudo também indica que, apesar de várias diferenças biogeográficas, a hidrologia parece ser o principal fator que controla a produção primária, secundária e a sustentabilidade em rios e lagos (reservatórios). Em conclusão, a hidrologia nos trópicos parece diminuir os efeitos esperados de uma temperatura mais elevada. Portanto, para aumentar a resiliência nas águas doces tropicais ações integradas de acordo com as fases hidrológicas são altamente recomendadas.
33

Changes in the South Atlantic Subtropical Gyre circulation from the 20th into the 21st century / Mudanças na circulação do Giro Subtropical do Atlântico Sul do século 20 para o século 21

Fernanda Marcello de Oliveira 09 March 2017 (has links)
Through analysis of large-scale ocean gyre dynamics from simulation results of the ocean component of the Community Earth System Model version 1 - the Parallel Ocean Program version 2 (CESM1-POP2) - this study builds upon existing research suggesting recent changes in the circulation of global subtropical gyres with respect to the South Atlantic Ocean. Results all point to an increase in the total counterclockwise circulation and a southward displacement of the sub- tropical gyre system. The northern boundary of the South Atlantic Subtropical Gyre (SASG) is represented by the bifurcation of the southern branch of the South Equatorial Current (sSEC) into the North Brazil Undercurrent/Current (NBUC/NBC) to the north and the Brazil Current (BC) to the south. The sSEC Bifurcation Latitude (SBL) dictates the partition between waters flowing poleward and those flowing equatorward. Although a northward migration of the SBL would be expected with the gyre spin up and associated poleward transport increase, the SBL migrates southwards at a rate of 0.051o/yr, in conjunction to a substantial increase in the equatorward advection of waters within the sSEC-SBL-NBUC system, which is included in the upper-branch of the Atlantic Meridional Overturning Circulation. / Através de análises da dinâmica de grande-escala do giro oceânico, proveniente dos resultados de simulação da componente oceânica do Community Earth System Model versão 1 - o Parallel Ocean Program versão 2 (CESM1-POP2) - este estudo se baseia em estudos prévios sugerindo mudanças recentes na circulação dos giros subtropicais globais, com respeito ao oceano Atlântico Sul. Os resultados apontam para uma intensificação da circulação anti-horária e um deslocamento para sul de todo o sistema do giro subtropical. A borda norte do Giro Subtropical do Atlântico Sul (GSAS) é representada pela bifurcação do ramo sul da Corrente Sul Equatorial (CSEs) em Subcorrente/Corrente Norte do Brasil (SCNB/CNB) para norte e Corrente do Brasil (CB) para sul. A Latitude da Bifurcação da CSEs (LBC) determina a partição entre as águas fluindo em direção ao pólo e aquelas fluindo em direção ao equador. Embora seja esperada uma migração para norte da LBC com a aceleração da circulação do giro e consequente aumento do transporte em direção ao pólo, a LBC migra para sul a uma taxa de 0.051o/ano. Esta migração ocorre em conjunto à um aumento substancial na advecção de águas em direção ao equador com o sistema CSEs-LBC-SCNB, o qual está incluso no ramo superior da Circulação de Revolvimento Meridional do Atlântico.
34

Contribution à l'analyse de la transformation du système de gouvernance des universités à travers la mise en place de l'audit légal / A contribution in the analysis of the University’s governance system transformation through the implementation of the legal audit

El Kaddouri, Hamza 13 December 2016 (has links)
Les universités françaises ont fait l’objet d’un ensemble de réformes qui, dans l’esprit, visent à moderniser leur gestion et leur mode de gouvernance. Ces réformes se sont traduites par la mise en place d’un ensemble de mesures notamment l’adoption de la Loi Relative aux Universités (LRU) en 2007 qui permet auxdites universités d’accéder aux Responsabilités et Compétences Elargies (RCE). Ce passage s’est accompagné de l’obligation de certification des comptes des universités par un auditeur légal dont la mission d’audit vient s’ajouter à un ensemble complexe de mécanismes de gouvernance des universités déjà en place. En conséquence, le problème qui se pose est la question de l’utilité et de l’apport potentiel d’un contrôle externe supplémentaire au sein des universités.Cette thèse a pour objectif d’examiner les facteurs d’efficience et de légitimité de la de la transformation du système de gouvernance des universités par l’introduction de l’audit légal à travers deux objectifs : d’une part, explorer les perceptions qu’ont les membres des équipes dirigeantes du rôle de l’audit légal dans la gouvernance et son impact sur la latitude managériale des présidents des universités et d’autre part, mettre en évidence l’apport potentiel de l’audit légal au système de gouvernance en place.Pour répondre à ses objectifs, nous avons opté méthodologiquement pour une approche mixte combinant les études qualitative (46 entretiens) et quantitative (113 questionnaires exploitables) réalisées auprès des équipes dirigeantes des universités. Les résultats révèlent que l’audit légal, en tant que mécanisme de gouvernance, contribue en dynamique à réduire et à renforcer la latitude managériale des dirigeants des universités, et sa dimension cognitive semble être dominante aux yeux des équipes dirigeantes des universités. Cette étude met également en évidence certaines insuffisances du système de gouvernance des universités et montre le rôle de complémentarité joué par l’audit légal. En ce sens, cette recherche contribue à une approche intégrée de la gouvernance, en examinant la complémentarité des dimensions disciplinaire et cognitive de l’audit légal au sein d’un système de gouvernance.Cette thèse montre par conséquent la contribution de l’audit légal à l’amélioration de l’efficacité du système de gouvernance des universités. / The French Universities were submitted to a pool of reforms and measures that were aiming to modernize their management and governance process. These reforms are translated by the implementation of a set of measures, especially by the adoption of the « Loi Relative aux Universités LRU » in 2007 which allows Universities to have access to the « Expanded Responsibilities and Competencies » (Responsabilités et Compétences Elargies RCE). This transition to RCE states that it’s an obligation to certificate the accounts of the University by an external auditor, whose audit mission is in addition to the existing complex governance system. Consequently, the main question is the utility and the potential contribution of a supplementary external control within the Universities.The purpose of this research is to assess the efficiency and the legitimacy factors of the transformation process in the University’s governance system by introducing the legal audit through two main objectives: firstly, exploring the management team’s perceptions of the role that the legal audit has in the governance process and its impact on the president’s managerial latitude; and secondly, highlighting the potential contribution of the legal audit to the current governance system.In order to meet the objective of the research, we have chosen a mixed methods approach by combining a qualitative (46 interviews) with a quantitative study (113 questionnaires), realized with the help of the University’s management teams. The results reveal that legal audit, as a governance mechanism, is contributing simultaneously at diminishing and reinforcing the managerial latitude of a President in an University and that the cognitive dimension appears to be prevailing in the eyes of the University’s management teams. This study highlights also certain weaknesses of the governance system in the universities and underlines the complementarity role of the legal audit. Therefore, this thesis contributes to an integrated approach of the governance by examining the complementarity between the disciplinary and the cognitive dimensions of the legal audit.In conclusion, this research illustrates the contribution of the legal audit for improving the efficiency of the governance system in the French Universities.
35

Global study of lake surface water temperature (LSWT) behaviour and the tuning of a 1-dimensional model to determine the LSWTs of large lakes worldwide

Layden, Aisling January 2014 (has links)
Lake surface water temperatures (LSWTs) of 246 globally distributed large lakes were derived from Along-Track Scanning Radiometers (ATSR) for the period 1991 to 2011. These LSWTs, derived in a systematic manner, presents an ideal opportunity to study LSWT behaviour on a global scale. In this thesis, the annual cycles of lake-mean LSWTs derived from these data quantify the responses of large lakes’ surface temperatures to the annual cycle of forcing by solar radiation and the ambient air temperature. Minimum monthly net surface solar irradiance (netSSI) strongly influences minimum LSWTs of non-seasonally ice covered lakes (where lake-mean LSWT remains above 1 ºC throughout the annual cycle), explaining > 0.88 (R2 adj) of the inter-lake variation in both hemispheres. In some regions, for seasonally ice covered lakes (where lake-mean LSWT remains below 1 ºC for part of the annual cycle) the minimum monthly netSSI is a better predictor than latitude, of the length of the frozen period, which shows the importance of local cloud climatological conditions. Additionally, at lake locations between 1º S to 12º N, the netSSI, shown to peak twice annually, is reflected in the LSWT annual cycle. The summer maximum LSWTs of lakes from 25º S to 35º N show a linear decrease with increasing altitude; -3.76 + 0.17 ºC km-1 (R2 adj = 0.95), marginally lower than the corresponding air temperature -4.15 + 0.24 ºC km-1 (R2 adj = 0.95) decrease with altitude. The start and end of the period where the lake-mean LSWT is greater than 4 ºC shows strong correlation with the spring and autumn 0 ºC air temperature crossing days, (R2 adj = 0.74 and 0.80 respectively). The temporally and spatially resolved LSWT observations allows for a greater practical understanding of LSWT behaviour of large lakes. For example, lakes with a greater LSWT annual range have more observed variability in the LSWT extremes, highlighting that they may be more responsive to changes in the climate than lakes with a low annual range. The nighttime LSWT trends show stronger warming than day-night trends in the all regions, except Europe. The lake centre LSWT trends and absolute values can be generally considered representative of the lake-mean LSWT trends and absolute values. The observed LSWT time series are used to tune a 1-dimensional thermodynamic lake model, FLake. By tuning FLake using only 3 basic lake properties, shown by myself to have the most influence over LSWTs (depth, snow and ice albedo and light extinction co-efficient), the daily mean absolute differences for 244 lakes is reduced from 3.38 + 2.74 ºC (untuned model) to 0.85 + 0.61 ºC (tuned model). The effect of wind speed, lake depth, albedo and light extinction co-efficient on LSWTs is demonstrated throughout the tuning process. The modelled summer LSWT response to changes in ice-off is strongly affected by lake depth and latitude explaining 0.50 (R2 adj, p = 0.001) of the inter-lake variation in summer LSWTs. Lake depth alone explains 0.35 (p = 0.003) of the variation, highlighting the sensitivity of the summer LSWTs of deeper lakes to changes in the ice-off. Statistically significant summer/ maximum month modelled LSWT trends, from 1979-2011 are presented for lakes where the modelled LSWTs are strongly supported by observed LSWTs over the period of available observed LSWTs. For these lakes, the trends show LSWT warming of between 0.73 – 2.10 ºC for 29 lakes in northern temperate regions over the 33 year period (1979 – 2011). The modelled regional trends of all lakes over the same period show least warming in Africa of 0.30 ºC and the greatest warming in Europe, 1.35 º.
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Ecological investigations of euphausiids at high latitudes

Saunders, Ryan Alexander January 2007 (has links)
1. Euphausiids are an important component of high latitude pelagic ecosystems, but there is a paucity of information on their distribution, abundance and population processes on within-year time scales. This thesis encompasses new research into the euphausiid-ocean component of two important high latitude ecosystems (South Georgia and the Irminger Sea) on sub-annual time scales. 2. A new method for measuring abundance of Antarctic krill (Euphausia superba) continuously at South Georgia (Southern Ocean) was devised using upward-looking acoustic devices deployed on moorings. These novel platforms provide a new window of observations onto marine systems not open from conventional research vessels. At South Georgia, the moorings provided data at a high temporal resolution giving completely new insight to the function of the coupled biological-physical marine ecosystem. The use of moorings may aid ecosystem-based management at South Georgia and elsewhere. 3. Analysis of mooring data collected between October 2002 and December 2005 indicated a regular annual cycle in krill density: high in summer and low in winter. Mooring estimates of krill density were not statistically different from estimates derived from standard ship-based surveys in adjacent time periods suggesting that the mooring point estimates had relevance in a wider spatial context (c. 100 x 100 km). The results indicated that because of the sharp peaks in the biomass cycle, the exact timing of repeated ship-based acoustic surveys might be critical. Surveys that differ in their timing by only a few weeks might exhibit quite different estimates of biomass because they fall at different points of the cycle. Additionally, within this intra-annual framework, annual ship-based surveys may be able to detect differences between high and low krill years only if they differ by densities of c. 35 g per square m. in summer and c. 20 g per square m. in winter. 4. The mechanisms driving intra-annual variability in Antarctic krill density at South Georgia are likely to be complex. Analysis of mooring data revealed a possible association between high krill density and low water temperatures (at 200 m) at South Georgia. There was evidence that seasonal variation in krill density off-shelf was linked to seasonal variation in current velocity: marked increases in velocity at the end of summer coincided with marked decreases in krill density and abrupt changes in water temperature characteristic of the Sub-Antarctic Current Front (SACCF). Oceanographic data indicated that the SACCF might have impinged in proximity to the moorings during the winter season. However, krill densities were low during these periods and analyses suggest that seasonal variations in krill density were not driven by seasonal oscillations in the position of the SACCF. The data are not consistent with a pattern of seasonal growth, production and mortality of a resident krill population at South Georgia, but are consistent with the notion of large influxes of krill in early summer, and of a predator-driven reduction at between mid- and late-summer. 5. The seasonal distribution, abundance and growth of key euphauiids in the Irminger Sea, North Atlantic was quantified using the first net haul data from the region since the 1930s. Results show a high degree of spatial heterogeneity in the seasonal distribution of euphausiid abundance/biomass during 2001-2002. There was evidence to suggest regional variation in growth and population processes of Meganyctiphanes norvegica and Thysanoessa longicaudata, and this corresponded broadly to distinct physical zones in the Irminger Sea. There were, however, no significant links between growth and temperature and chlorophyll a concentration. This was attributed to high spatial and temporal variability in biological and physical sampling. These data are a prerequisite for understanding ecosystems dynamics in the North Atlantic, and are important for robust ecosystem-based management strategies. 6. Controls on euphausiid spatial heterogeneity at high latitudes are likely to be complex. Important factors include horizontal advection, temperature, resource availability and behavioural mechanisms. Short-term (intra-annual), small-scale (basin-scale) data are fundamental to understanding variability in euphausiid abundance and distribution on broader spatial and temporal scales in these ecosystems.
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Linking mid-latitude storms, atmospheric composition and climate variability

Knowland, Katherine Emma January 2016 (has links)
In this thesis, the role of mid-latitude cyclones in air pollution transport in the Northern Hemisphere is quantified. The storm tracking model, TRACK, is used to study the mechanisms through which pollution, specifically ozone (O3) and carbon monoxide (CO), are vented from the boundary layer to the free troposphere and thus transported over large distances, as well as the introduction of O3 from the stratosphere into the troposphere. The relationship between mid-latitude cyclones and air pollution transport of O3 and CO is explored for the first time using the Monitoring Atmospheric Composition and Climate (MACC) reanalysis, a combined meteorology and composition reanalysis dataset. A comparison between springtime surface ozone measurements at rural background sites on the west coast of Europe and cyclone track frequency in the surrounding regions was used to first establish the correlation between cyclone location and surface air quality. The focus is on spring as it tends to be the season of maximum intercontinental transport of O3. The surface observations were compared to the MACC O3 values at the same locations and case studies of how cyclones can influence surface O3 measurements are described. When cyclones track north of 53°N, there is a significant probability that the surface O3 will be high (> the 75th percentile), due to the close proximity to stratospheric intrusions and the transport at low levels across the North Atlantic Ocean. The most intense spring cyclones (95th percentile) were selected for two regions, the North Atlantic and the North Pacific, for further investigation into the mechanisms which impact O3 and CO concentrations near cyclones. These intense cyclones ( 60 over each region) often tracked over the major emission sources of eastern North America and East Asia. The distributions of MACC O3 and CO within a "typical" intense cyclone are examined by compositing the cyclones together. The cyclone-centered composites were compared to background composites of "average conditions" created by sampling the reanalysis data of the previous year to the cyclone locations. Mid-latitude cyclones are found to redistribute concentrations of O3 and CO horizontally and vertically throughout the cyclone. This is clearly shown to occur through two main mechanisms: (1) vertical lifting of CO-rich and O3-poor air isentropically from near the surface to the mid- to upper-troposphere in the region of the warm conveyor belt; and (2) descent of O3-rich and CO-poor air isentropically in the vicinity of the dry intrusion, from the stratosphere toward the mid-troposphere. This work was expanded to identify the links between teleconnection patterns, mainly the North Atlantic Oscillation (NAO), that affect the major storm track pathways in the North Atlantic sector and the distribution of MACC O3 and CO throughout the troposphere and lower stratosphere. For this analysis, TRACK was used to calculate seasonal weighted-average O3 and CO distribution maps based on the monthly NAO index. During positive NAO phase, the persistence of low pressures over the North Atlantic coupled with the Azores High promotes transport across the North Atlantic throughout the troposphere. During negative NAO phase, blocking high pressure in the eastern North Atlantic are known to occur, which shifts transport pathways to a more southerly zonal flow. This work demonstrates the complex relationship between the horizontal and vertical distribution of pollution, including surface concentrations, and synoptic-scale systems.
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Self-Efficacy, Decision Latitude, and Work Ethic Among Educated Women

Harris, Elisa 01 January 2019 (has links)
Although women are more likely to seek advanced degrees, there are substantial gaps between men and women in terms of employment rates, wages, and positions of power. This cross-sectional study aligned with the social cognitive career theory and investigated how specific demographic variables (age and education level) interacted and influenced work-related characteristics (decision latitude, self-efficacy, and work ethic) to address issues women experience in the workplace. Females who identified as working a minimum of 15 hours per week and over the age of 18 were contacted via social media or in person. A snowball effect occurred when participants invited peers to participate. Two-hundred and eighty-six females completed an online survey including demographic questions and items from 3 instruments: Job Content Questionnaire, Short Occupational Self-Efficacy Scale, and Multidimensional Work Ethic Profile-Short Form. The research questions helped evaluate the differences and interactions between the independent variables age and education level on the dependent variables decision latitude, self-efficacy, and work ethic. Six one-way analyses of variance were used to assess for differences, and 3 two-way analyses of variance were used to assess for interactions between 5 age groups and 4 education levels. The analyses showed only 1 significant difference between education level and decision latitude. The current research may influence social change at an individual level within career or therapeutic counseling and policies and procedures at the organizational level. The information can create positive change for women within current work environments as they increase responsibilities or advance to positions of power.
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Comparisons of the biological and genetic characteristics of the Mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia

bryn_farmer@hotmail.com, Bryn Farmer January 2008 (has links)
The research conducted for this thesis has produced quantitative data on the biology and population genetic structure of the Mulloway Argyrosomus japonicus in Western Australia, where this sciaenid is recreationally and commercially fished. These data were used 1) to test various hypotheses regarding the relationship between key biological characteristics of A. japonicus and both latitude and environmental variables, 2) to investigate the population structure and genetic characteristics of populations of A. japonicus on the west and south coasts of Western Australia and to assess the relationships between these populations and those of A. japonicus in eastern Australia and South Africa, and 3) to consider the implications of the biological and genetic results for management.
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Linking landscape variables, hydrology and weathering regime in Taiga and Tundra ecoregions of Northern Sweden

Smedberg, Erik January 2008 (has links)
<p>High-latitude watersheds have been regarded as a carbon sink with soil carbon accumulating at low temperature. This sink is now believed to turn into a source, acting as positive feedback to climate warming. However, thawing permafrost soils would allow more water to percolate down to deeper soil layers where some of the carbon could be “consumed” in weathering and exported as bicarbonate to the sea. Using a hydrological mixing model showed that this could counterbalance the predicted positive feedback resulting from thawing soils.</p><p>Vegetation-covered riparian zones in headwater areas appear to have a significant role for the dissolved constituent fluxes. Higher concentrations of weathering products are found in taiga and tundra rivers with larger areas of forest and peat cover in the watershed. These landscape elements can thus be regarded as “hot spots” of river loading with dissolved constituents.</p><p>Comparing a regulated and an unregulated river tested the hypothesis that damming leads to a depletion of major elements also in oligotrophic river systems as a consequence of changes in landscape elements. A loss of upper soils and vegetation through inundation prevents the contact of surface waters with vegetated soil, and consequently reduces weathering fluxes. The hypothesis that the lower fluxes of dissolved silica (DSi) in the regulated river could also be explained by biological uptake was then tested using a model, and budget calculations indicate a significant reduction as a result of regulation. About 10% of this reduction can be attributed to the flooding of the fluvial corridor and the rest to diatom blooms in the reservoirs. A more detailed study of landscape elements for the headwaters of the river Luleälven showed that only 3% of the surface area has been inundated by reservoirs but ca. 37% of the deciduous forest. Such a significant loss of hot spots may indeed explain the observed lower DSi fluxes in the regulated watersheds of northern Sweden.</p>

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