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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

Climate-induced changes of vegetation in broadleaved deciduous forests / Plačialapių lapuočių miškų augalijos kaita skirtingais klimatinių sąlygų metais

Abraitienė, Jolita 24 October 2012 (has links)
The aim of the study was to investigate the influence of meteorological factors on the phenological phases of the vegetation in broadleaved forests under varying climatic conditions. To attain the aim, the following objectives were set: 1. Characterize the changes of values of meteorological parameters (temperature, precipitation) in the studied period; 2. Determine solar radiation intensity under the canopies of trees, phenological phases of trees and bushes and their changes; 3. Determine the changes of projection coverage, height and phenological phases of herbaceous plants during the growing period; 4. Ascertain the relationship between meteorological factors and phenological phases of woody and herbaceous plants. Scientific novelty, theoretical and practical significance. Up till now in Lithuania phenological studies mostly of agricultural plants have been conducted. Phenological studies on woody and herbaceous plants in the forests of Lithuania are almost absent. Most of the studies were conducted with indicator species, such as hazel, coltsfoot, etc. During the study, for the first time in Lithuania a complex investigation of forest community was carried out and the influence of meteorological factors on the phenological phases of herbaceous and woody plants in Kamša botanical-zoological reserve was determined. The results of the study allow to better assess the influence of meteorological factors on seasonal development (phenology) of herbaceous plants, trees and... [to full text] / Darbo tikslas – ištirti meteorologinių veiksnių įtaką plačialapių lapuočių miškų augalijos fenologiniams tarpsniams skirtingų klimatinių sąlygų metais. Tyrimo uždaviniai: 1. charakterizuoti meteorologinių rodiklių (temperatūros, kritulių) reikšmių kaitą tiriamuoju laikotarpiu; 2. nustatyti apšvietimą po medžių lajomis, medžių ir krūmų lapojimo fenologinius tarpsnius ir jų pokyčius; 3. nustatyti žolinių augalų projekcinio padengimo, aukščio, fenologinių tarpsnių kaitą vegetacijos metu; 4. nustatyti ryšį tarp meteorologinių veiksnių ir sumedėjusių, žolinių augalų fenologinių tarpsnių. Darbo mokslinis naujumas, teorinė ir praktinė reikšmė. Lietuvoje iki šiol daugiausia atlikta fenologinių tyrimų su žemės ūkio augalais. Sumedėjusių augalų ir miško žolinių augalų detalių fenologinių tyrimų Lietuvoje beveik nėra. Daugiausia atlikta indikatorinių rūšių, kaip paprastasis lazdynas, paprastasis šalpusnis ir kt., tyrimų. Pirmą kartą Lietuvoje kompleksiškai tirta miško bendrija, nustatyta meteorologinių veiksnių įtaka sumedėjusių augalų lapojimo ir žolinių augalų fenologiniams tarpsniams Kamšos botaniniame-zoologiniame draustinyje. Darbo rezultatai leidžia geriau įvertinti meteorologinių veiksnių įtaką miško žolinės augalijos, medžių ir krūmų sezoniniam vystymuisi (fenologijai). Gautos žinios svarbios ne tik teoriniam išsamesniam atskirų rūšių biologijos pažinimui, bet ir praktiniams tikslams: dendrologijoje, fitopatologijoje ir t. t.
32

Climate model study of the role of global climate in the late Pleistocene migration of anatomically modern humans out of Africa

Carto, Shannon Leigh 26 January 2010 (has links)
According to the "Out-of-Africa 2" theory of human evolution all living humans today descend from a group of Anatomically Modern Homo sapiens or Anatomically Modem Humans that evolved in Africa 200,000 years ago and subsequently migrated out of Africa and spread into the rest of the World around 100,000 years. As a result an interest has developed in establishing a concrete theory of the factors that compelled and/or motivated our ancestors to venture out of their African origins at this time. Interestingly, the Earth's Last Glacial Cycle also dates from this period--stretching from 115,000 to 10,000 years ago. Current paleoclimate evidence suggests that the climatic repercussions of this glacial cycle in Africa resulted in a shift towards a drier and somewhat cooler climate state and the fragmentation of the formerly extensive forested African landscape. As a result, theories of early human migration have cited African climate change during the late Pleistocene as a determinant; however, the mechanisms responsible for the development of hyper-arid conditions in Africa at this time have remained unresolved. Although, past global climate change has been ascribed to changes in radiative forcing and changes in atmospheric carbon dioxide, recent paleoclimate studies have revealed that African climate is sensitive to changes in SSTs in the Atlantic, as it appears that subtropical Africa was more arid when North Atlantic sea surface temperatures (SSTs) were cold during glacial periods. The forcing mechanism believed to be responsible for the development of these cold SSTs are the so-called Heinrich Events that are documented as massive surges of icebergs (from high-latitude ice sheets) into the North Atlantic Ocean during high-latitude glaciations. These Heinrich events resulted in the release of large quantities of freshwater into the North Atlantic, which in turn led to a weakening on the global ocean thermohaline circulation and widespread cooling throughout the region. In particular, marine sediment records from the Nordic Sea document a widespread cooling and ice-rafting event that occurred around 105 kya, known as Heinrich event 9. In order to investigate the climate processes responsible for promoting cooler and drier conditions in Africa during the migration event of AMH (around 100 kya) I used the University of Victoria Earth System Climate Model (UVic ESCM) to conduct two climate model experiments that compared the global-scale response of climate at 105 kya, in particular the Atlantic Ocean and the African climate system, to: 1) orbitally-controlled solar radiation and atmospheric carbon dioxide forcing appropriate for 105 kya and 2) the combined effect of orbitally-controlled solar radiation and atmospheric carbon dioxide at 105 kya, and North Atlantic freshwater forcing. The ultimate goal of this study is to understand how low-latitude and high-latitude climate processes affect the African climate. Overall the comparative analysis of these two climate model states revealed that the complex interaction between orbitally-controlled solar radiation and atmospheric CO2 forcing at 105 kya produced a significant part of the cooling and drying in Africa at this time interval. However, the model also indicated that the climate perturbations, caused by the freshwater forcing, amplified the cooling and drying that was already taking place in Africa due to orbital and CO2 forcing. Guided by paleoclimate data, archaeological data and the results of this study, I consider it likely that the development of hyper-arid conditions in Africa around 100 kya served as the impetus for the migration event of AMH out of Africa, as these climate changes would have rendered Africa unsuitable for hominid occupation at this time. These climate model results also provide compelling evidence that high-latitude cold events, induced by Heinrich Events, are strongly covariant with African aridity, and thus provide support to previous assertions that North Atlantic climate changes can be effectively propagated throughout the globe to produce seemingly simultaneous climate change.
33

Climate change impacts on the catchment contribution to lake water quantity and quality /

Moore, Karen, January 2007 (has links)
Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill 5 uppsatser.
34

Spatiotemporal relationships between climate and whitebark pine mortality in the greater Yellowstone ecosystem

Jewett, Jeffrey Thomas. January 2009 (has links) (PDF)
Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Rick L. Lawrence. Includes bibliographical references (leaves 93-106).
35

Emise skleníkových plynů při pěstování zeleniny / Greenhouse gasses emission load during vegetable growing

KRATOCHVÍLOVÁ, Pavla January 2013 (has links)
This thesis is focused on a survey whether the production of greenhouse gases by cultivation of vegetable, concretely garlic, is higher in a conventional way of cultivation or in an organic way of cultivation of garlic (from view of the environment). The study is composed on the base of all system processes which are used during cultivation of garlic. It was clear from collection of input data (which were obtained by questionnaire or telephone survey) that main processes for calculation would be mainly agricultural processes. An emission load of CO2 equivalent to a kilogram of individual product was calculated from obtained data and information from a database Ecoinvent. The purpose of this work is making information about possibility of choice of food and its influence on the environment available to people. It should help them to choose which food they want to eat. The conclusion of this thesis is the result which shows that organic cultivation of garlic is more sparing to the environment because it produces less emission than conventional agriculture.
36

Emise skleníkových plynů v živočišné výrobě / Greenhouse gasses emission load within animal production

LAŠTŮVKOVÁ, Jana January 2013 (has links)
This thesis deals with a quantity of CO2 emissions produced during breeding of pigs. Two systems of farming (conventional and organic) were compared between each other. With help of questionnaire survey the data were obtained ? they were needed for a calculation of CO2 emissions in software program SIMA PRO which calculates emissions produced in agricultural phase: the breeding of animal from its birth to the end of fattening and converts them into CO2 equivalent. The aim of this work was to find out, which system of farming produces more CO2 emissions.
37

Vliv vodního stresu na klíčení a růst trav a jetelovin / The influence of water stress on germination and growth of grasses and legumes

HRDA, Lukáš January 2014 (has links)
The negative impact of climate change on agricultural production is consistently increasing all over the world. As a result of these changes, the yields of some crops have been decreasing. The main problems include frequent weather changes, especially long periods of drought accompanied by high temperatures. The aim of this diploma thesis was to assess the effect of water deficit on offshoot germination and longevity of selected species of grasses and clovers. The evaluation of resistance to water deficit was carried out using both laboratory and pot experiments. The results of these experiments were used to evaluate the drought resistance of the tested species of grasses and legumes. Based on the proven drought resistance, appropriate species and varieties have been recommended for cultivation in conditions of water deficit. The issue of drought resistance is to be paid more and more attention in the future. According to most forecasts, increasingly long periods of drought are likely to occur. For this reason, there will be the need for crops and varieties that best resist to various abiotic stresses.
38

[en] ANALYSIS OF THE COORDINATION AND ALIGNMENT BETWEEN THE CLIMATE MITIGATION STRATEGIES OF BRAZIL AND THE CITIES OF RIO DE JANEIRO, SÃO PAULO AND BELO HORIZONTE / [pt] ANÁLISE DA COORDENAÇÃO E DO ALINHAMENTO ENTRE AS ESTRATÉGIAS CLIMÁTICAS DE MITIGAÇÃO DO BRASIL E DAS CIDADES DO RIO DE JANEIRO, SÃO PAULO E BELO HORIZONTE

GABRIELLA MELLO LATTARI 28 September 2018 (has links)
[pt] Em setembro de 2016, no Acordo de Paris, o Brasil, por meio de sua iNDC, assumiu o compromisso de reduzir em 37 por cento suas emissões de GEE até 2025 e em 43 por cento até 2030, com base nos níveis de emissão de 2005. Estas metas foram estabelecidas a partir de uma visão da esfera nacional. Os governos locais tiveram pouca ou nenhuma participação nas discussões e estudos que levaram à elaboração da iNDC brasileira e, portanto, pouco puderam contribuir com a visão de menor escala, apesar da crescente influência das cidades no contexto climático global. Esta falta de articulação entre os níveis de governo dificulta a cooperação vertical entre eles. Neste cenário é possível questionar a coordenação e o alinhamento entre as estratégias climáticas de mitigação nacionais e locais. Com esta preocupação em foco, este trabalho busca avaliar as coerências e divergências entre as estratégias de mitigação de emissão de GEE do Brasil com as estratégias de três grandes capitais brasileiras: Rio de Janeiro, São Paulo e Belo Horizontes. A avaliação da coordenação e do alinhamento entre as estratégias climáticas das três cidades e do Brasil foi realizada à luz de oito critério comuns nas estratégias climáticas padrões. A partir das análises realizadas, percebe-se que não há coordenação entre as estratégias climáticas analisadas. Dos oito critérios avaliados, apenas em um foi encontrado alinhamento entre as quatro estratégias, o que prejudica a mitigação tanto no nível local quanto nacional, dificultando o alcance das metas e compromissos assumidos por ambos os níveis de governo. / [en] The aim of the Paris climate agreement is to guide governments actions to limit global average temperature rises by up to 2 degrees Celsius above pre-industrial levels, with substantial commitment of the Parties to ensure that this increase does not exceed 1.5 degrees Celsius (Rogel, 2016). This agreement seeks to establish a compromise that is not so bold as to be unacceptable to the parties, but also not so trivial as to be ineffective. The nations theirselves that stipulate their goals and contributions to achieve the central objective through so-called Intended Nationally Determined Contributions (iNDCs), which exposes how each Nation intends to reduce GHG emissions according to their own characteristics, needs and economic and social interests (Brazilian Ministry of the Environment website). Brazil through it s iNDC has comitted to reduce GHG emissions by 37 percent in 2025 and 43 percent in 2030 compared to 2005 levels. The goals and contributions assumed by Brazil were decided and stipulated based on a vision of the national sphere. Local governments had little or no participation in the discussions and studies that led to the elaboration of the Brazilian iNDC, and therefore did not have the opportunity to contribute to the vision of a smaller scale. However, according to IBGE, currently around 85 percent of the Brazilian population is urban, and this high concentration of inhabitants makes cities more vulnerable to climate change, as well as more cost-effective for mitigation and adaptation actions. In addition, the generation of knowledge, innovations, agile communication and dissemination of information, economic importance and proximity between governors and their population are other factors that make cities important pieces in the climate context. However, despite this growing influence of cities in the global climate context, the Brazilian federal government continues to focus in rural issues, with little consideration of urban climate issues. On the other hand, cities are advancing and leading the urban climate theme with little or no support from the federal government, which represents a big loss of opportunity for vertical cooperation between different levels of government. In this context, the coordination and alignment between national and local climate mitigation strategies is questioned, and it is discussed how different levels of government can cooperate with one another in order to address their climate challenges in a coordinated and cohesive way. Therefore, the goal of this paper is to evaluate the coherence and divergence between the climate mitigation strategies of GHG emissions of Brazil and the cities of Rio de Janeiro, São Paulo and Belo Horizonte and to suggest actions that facilitate the coordination of these strategies. These three cities were chosen because they are capitals with national influence and mainly because they present an advanced climate agenda.
39

Resposta das circulações oceânica e atmosférica associada ao enfraquecimento da circulação termohalina global / Response of the oceanic and atmospheric circulations associated with the weakening of global thermohaline circulation

Machado, Jéferson Prietsch 28 July 2009 (has links)
Made available in DSpace on 2015-03-26T13:50:02Z (GMT). No. of bitstreams: 1 texto completo.pdf: 3607155 bytes, checksum: 0ba931da234b886d1f1b534578664639 (MD5) Previous issue date: 2009-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The global thermohaline circulation (THC) is the transport of ocean water masses caused by differences in the sea water density due to variations in temperature and salinity. Studies have shown that increased precipitation in high latitudes of the Northern Hemisphere and the sea ice melting of the Arctic region generates a freshwater flow of in the North Atlantic which is able to shutoff the formation of deep water and hence desintensifies the THC. Considering the above, this study investigates the anomalous pattern of the oceanic and atmospheric circulation by introducing an increase of 1 Sverdrup (Sv) (1 Sv = 106m3s-1) of freshwater into the North Atlantic, based on simulations performed with the LOVECLIM model. The results show that the weakening of the THC leads to strong cooling in the North Atlantic region whereas the extratropical Southern Hemisphere warms. The weakening of the THC also changes the patterns of atmospheric circulation, inducing a reduction in the subtropical jet speed due to the smooth thermal gradient between the equator and the southern hemisphere polar region. Furthermore, the intertropical convergence zone moves southwards and changes the precipitation regime of the north and the northeastern part of Brazil. The reduction of the THC also leads to changes in the baroclinic instability in the middle and high latitudes of the Southern Hemisphere. / A Circulação Termohalina Global (CTG) consiste no transporte de massas d água oceânicas associado a diferenças na densidade da água do mar devido a variações de temperatura e salinidade. Estudos têm demonstrado que o aumento da precipitação em altas latitudes do Hemisfério Norte e o derretimento do gelo da região do Ártico podem gerar um fluxo de água doce no Oceano Atlântico Norte, capaz de interromper a formação de água profunda e, conseqüentemente, reduzir a CTG. Diante do exposto, o objetivo do trabalho é investigar o comportamento anômalo das circulações oceânica e atmosférica devido a um aumento de 1 Sverdrup (Sv) (1 Sv = 106m3s-1) no transporte de água doce no Atlântico Norte, com base em simulações realizadas com um modelo climático acoplado (LOVECLIM). Os resultados demonstram que o enfraquecimento da CTG provoca um forte resfriamento no Atlântico Norte enquanto que a região extratropical do Hemisfério Sul aquece. A inibição da CTG também muda os padrões da circulação atmosférica, se observa uma redução na corrente de jato subtropical devido o menor gradiente térmico entre o equador e a região polar austral. Além disso, a zona de convergência intertropical desloca-se para sul alterando o regime de precipitação das regiões norte e nordeste do Brasil. Por outro lado existe um enfraquecimento da instabilidade baroclínica nas latitudes médias e altas do Hemisfério Sul.
40

Modelo computacional para previsão de mortalidade de galinhas poedeiras em função de ondas de calor e tipologia dos aviários / Computational model for prediction of laying hens mortality due to heat waves and avian typology

Riquena, Rodrigo da Silva [UNESP] 13 February 2017 (has links)
Submitted by RODRIGO DA SILVA RIQUENA null (r.riquena@hotmail.com) on 2017-04-08T14:36:36Z No. of bitstreams: 1 RodrigoRiquena_PGAD_TUPA_02217.pdf: 2586767 bytes, checksum: 6bbcda45670b228af1c74a3153a5c33e (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-17T14:58:41Z (GMT) No. of bitstreams: 1 riquena_rs_me_tupa.pdf: 2586767 bytes, checksum: 6bbcda45670b228af1c74a3153a5c33e (MD5) / Made available in DSpace on 2017-04-17T14:58:41Z (GMT). No. of bitstreams: 1 riquena_rs_me_tupa.pdf: 2586767 bytes, checksum: 6bbcda45670b228af1c74a3153a5c33e (MD5) Previous issue date: 2017-02-13 / A mortalidade na produção de galinhas poedeiras é fato preocupante para produtores e constitui considerável perda econômica. Alguns eventos climáticos, como ondas de calor, estão diretamente relacionados ao aumento da mortalidade. O objetivo deste trabalho foi relacionar a ocorrência de ondas de calor com a mortalidade de poedeiras, considerando o efeito de duas diferentes tipologias de galpão utilizado na produção de ovos. Os dados de mortalidade diária foram obtidos em dois aviários localizados na cidade de Bastos-SP para o período de outubro de 2014 a janeiro de 2016. Para padronizar a coleta de informações foi construída uma ferramenta para registro diário da mortalidade na granja. Os dados do clima foram obtidos de duas estações meteorológicas localizadas nos municípios Tupã-SP e Rancharia-SP para o período de 2010 a 2015. As ondas de calor foram classificadas na base de dados climática usando diferentes definições da literatura. Os dados de mortalidade e clima foram relacionados em um mesmo banco de dados e foram classificados em mortalidade normal e alta de acordo com manual da linhagem. Após serem relacionados os dados foram levados a mineração, a técnica utilizada foi a CRISP-DM utilizando o algoritmo J48. A classificação para ondas de calor do INMET foi a mais adequada para região. Foi possível associar as ocorrências de onda de calor ao aumento da mortalidade de poedeiras e as variáveis construtivas dos aviários influenciam na mortalidade e produção. A árvore de classificação gerada identificou com precisão 71%, das ocorrências de mortalidade alta e 95% de todos os dados de mortalidade. A árvore de classificação permitiu relacionar o aumento da mortalidade de poedeiras em função de ondas de calor e permite que se faça uma previsão de quando haverá maior chance de ocorrer mortalidade alta. / Mortality in the production of laying hens is a concern for producers and constitutes a considerable economic loss. Some climatic events, such as heat waves, are directly related to increase of mortality. The aim of this work was to relate the occurrence of heat waves with laying hens mortality, considering the effect of two different typologies of shed used in egg production. Daily mortality data were obtained from two aviaries located in the city of Bastos-SP for the period from October 2014 to January 2016. To standardize the collection of information, a tool was created to record daily mortality on the farm. The climate data were obtained from two meteorological stations located in the cities of Tupã-SP and Rancharia-SP for the period from 2010 to 2015. The heat waves were classified in the climatic database using different definitions of the literature. Mortality and climate data were related in a single database and were classified into normal and high mortality according to the lineage manual. After being related the data were taken to mining, the technique used was the CRISP-DM using the algorithm J48. The classification for INMET heat waves was the most adequate for region. It was possible to associate the occurrences of heat wave to the increase of laying hens mortality and the constructive variables of the aviaries influence the mortality and production. The classification tree generated accurately identified 71% of occurrences of high mortality and 95% of all mortality data. The classification tree allowed to relate the increase in laying mortality as a function of heat waves and allows a forecast of when there is a higher chance of high mortality occurrence.

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