• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 31
  • 26
  • 11
  • 7
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 103
  • 103
  • 65
  • 20
  • 19
  • 17
  • 15
  • 15
  • 15
  • 14
  • 12
  • 9
  • 9
  • 8
  • 8
  • 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.
21

Torkan 2018: Nationell kris eller klimatdebatt? : En kvantitativ innehållsanalys av lokal- och rikstäckande rapportering gällande torkan sommaren 2018. / The drought of 2018: A national crisis or a climate debate? : A quantitative content analysis of local and national reporting on the summer drought of 2018.

Käll, Oskar, Röriksson, Gustav January 2019 (has links)
This essay’s purpose is to investigate how the swedish media portrayed the swedish summer drought of 2018. With a quantitative content analysis focusing on two newspapers, one regional and one national, this essay answers how the drought of 2018 was portrayed from a local and national perspective, from a framing and environmental theoretical perspective. But also to what extent the newspapers connected the drought and global climate change and what voices that were emphasized in the texts concerning the drought of 2018.   This study shows that the swedish drought 2018 was portrayed with “straight” news reporting in both regional and local newspapers. The articles did rarely contain any sort of conflict and the actors in the articles were dominated by authorities and businessmen. The head consequence of the drought in both of the newspapers was the environment. Although, it was rarely connected with climate changes. In 90 percent of the local press-articles the climate change was not mentioned. Those times when the drought was connected with climate change, in both newspapers, it was in debate articles, often written by a journalist.
22

Modeling Aerosol - Water Interactions in Subsaturated and Supersaturated Environments

Fountoukis, Christos 05 June 2007 (has links)
The current dissertation is motivated by the need for an improved understanding of aerosol water interactions both in subsaturated and supersaturated atmospheric conditions with a strong emphasis on air pollution and climate change modeling. A cloud droplet formation parameterization was developed to i) predict droplet formation from a lognormal representation of aerosol size distribution and composition, and, ii) include a size-dependant mass transfer coefficient for the growth of water droplets which explicitly accounts for the impact of organics on droplet growth kinetics. The parameterization unravels most of the physics of droplet formation and is in remarkable agreement with detailed numerical parcel model simulations, even for low values of the accommodation coefficient. The parameterization offers a much needed rigorous and computationally inexpensive framework for directly linking complex chemical effects on aerosol activation in global climate models. The new aerosol activation parameterization was also tested against observations from highly polluted clouds (within the vicinity of power plant plumes). Remarkable closure was achieved (much less than the 20% measurement uncertainty). The error in predicted cloud droplet concentration was mostly sensitive to updraft velocity. Optimal closure is obtained if the water vapor uptake coefficient is equal to 0.06. These findings can serve as much needed constraints in modeling of aerosol-cloud interactions in the North America. Aerosol water interactions in ambient relative humidities less than 100% were studied using a thermodynamic equilibrium model for inorganic aerosol and a three dimensional air quality model. We developed a new thermodynamic equilibrium model, ISORROPIA-II, which predicts the partitioning of semi-volatiles and the phase state of K+/Ca2+/Mg2+/NH4+/Na+/SO42-/NO3-/Cl-/H2O aerosols. A comprehensive evaluation of its performance was conducted against the thermodynamic module SCAPE2 over a wide range of atmospherically relevant conditions. Based on its computational rigor and performance, ISORROPIA-II appears to be a highly attractive alternative for use in large scale air quality and atmospheric transport models. The new equilibrium model was also used to thermodynamically characterize aerosols measured at a highly polluted area. In the ammonia-rich environment of Mexico City, nitrate and chloride primarily partition in the aerosol phase with a 20-min equilibrium timescale; PM2.5 is insensitive to changes in ammonia but is to acidic semivolatile species. When RH is below 50%, predictions improve substantially if the aerosol follows a deliquescent behavior. The impact of including crustal species (Ca2+, K+, M2+) in equilibrium calculations within a three dimensional air quality model was also studied. A significant change in aerosol water (-19.8%) and ammonium (-27.5%) concentrations was predicted when crustals are explicitly included in the calculations even though they contributed, on average, only a few percent of the total PM2.5 mass, highlighting the need for comprehensive thermodynamic calculations in the presence of dust.
23

炭素同位体比を用いた森林土壌呼吸中の根呼吸の評価

YAMAZAWA, Hiromi, MORIIZUMI, Jun, HACHIYA, Masashi, 山澤, 弘実, 森泉, 純, 蜂谷, 真史 03 1900 (has links)
第22回名古屋大学年代測定総合研究センターシンポジウム平成21(2009)年度報告
24

Efeito do aumento da concentração de co2 atmosférico sobre o oídio, a ferrugem e o desenvolvimento de plantas de soja

Lessin, Ricardo Contreira [UNESP] 18 August 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-18Bitstream added on 2014-06-13T19:37:27Z : No. of bitstreams: 1 lessin_rc_me_botfca.pdf: 518732 bytes, checksum: 7e4d555398ff650c409d95422bc6f7ea (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os níveis de concentração de CO2 atmosférico estão se elevando nas últimas décadas devido principalmente à queima de combustíveis fósseis. Essa alteração atmosférica, além de intensificar o fenômeno do efeito estufa, pode afetar o comportamento de algumas plantas e microrganismos de interesse agrícola. O CO2, por ser um componente básico da fotossíntese, em alta concentração, pode causar alterações na morfologia e nos processos fisiológicos das plantas, assim como na interação destas com fitopatógenos. Sendo assim, o presente estudo teve por objetivo avaliar o efeito da alta concentração de CO2 atmosférico na severidade do oídio, causado por Microsphaera diffusa, e da ferrugem asiática, causado por Phakopsora pachyrhizi, na soja e também em alguns fatores relacionados ao desenvolvimento da planta que podem exercer influência na doença, como o crescimento, peso da matéria seca e nodulação. Foram realizados três ensaios em estufas de topo aberto com (E+CO2) ou sem (E) injeção de CO2 e sem estufa (T), correspondendo às concentrações de, aproximadamente, 647 ppm, 474 ppm e 453 ppm, respectivamente. No primeiro ensaio, foram avaliadas características de desenvolvimento da planta; no segundo, a severidade da ferrugem asiática, que ocorreu de forma espontânea; e no terceiro, a severidade do oídio em quatro cultivares com diferentes níveis de resistência. As cultivares foram: FT-Estrela, altamente suscetível (AS); Embrapa 48, suscetível (S); FT-Cometa, moderadamente resistente (MR) e FT-5 (Formosa), resistente (R). Nos resultados obtidos, foi verificado um aumento significativo na severidade do oídio, no tratamento com injeção de CO2,em folhas primárias e na planta inteira das cultivares analisadas em conjunto, mas não houve alteração na expressão de resistência das cultivares. Para a ferrugem asiática, houve redução da severidade... / The concentration of atmospheric CO2 is increasing in recent decades, mainly due to burning of fossil fuels. This atmospheric change can intensify the phenomenon of the greenhouse effect, and can affect the behavior of important agricultural plants and microorganisms. The CO2, as a basic component of photosynthesis, in high concentrations, can cause changes in morphological and physiological processes of plants, as well as interaction with plant pathogens. Therefore, this study aimed to assess the effect of high concentrations of atmospheric CO2 on the severity of powdery mildew in soybean, caused by Microsphaera diffusa, and also in some characteristics related to the development of the plant that may influence the disease, such as growth, weight of dry matter and nodulation. Three trials were developed under open-top chambers with (E+CO2) or without (E) injection of CO2 and without greenhouse (T), with the approximate concentrations of 647 ppm, 474 ppm, and 453 ppm, respectively. On the first trial, growth characteristics were evaluated, on the second, the severity of rust, caused by Phakopsora pachyrhizi, which occurred spontaneously; on the third, the severity of powdery mildew on four cultivars with different levels of resistance: FT-Estrela, highly susceptible (AS); Embrapa 48, ...(Complete abstract click electronic access below)
25

Cultivo de Eucalyptus urograndis em atmosfera enriquecida com CO2: mudanças no proteoma cloroplastidial / Eucalyptus urograndis growth under CO2-enriched atmosphere: changes in the chloroplast proteome

Santos, Bruna Marques dos [UNESP] 30 March 2016 (has links)
Submitted by BRUNA MARQUES DOS SANTOS null (brunamarques.bio@gmail.com) on 2016-05-20T14:43:34Z No. of bitstreams: 1 Dissertação_Bruna_Marques_Santos.pdf: 2509707 bytes, checksum: d5b8e8138728f1d899f6f957bedf5425 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-05-24T14:23:17Z (GMT) No. of bitstreams: 1 santos_bm_me_jabo.pdf: 2509707 bytes, checksum: d5b8e8138728f1d899f6f957bedf5425 (MD5) / Made available in DSpace on 2016-05-24T14:23:17Z (GMT). No. of bitstreams: 1 santos_bm_me_jabo.pdf: 2509707 bytes, checksum: d5b8e8138728f1d899f6f957bedf5425 (MD5) Previous issue date: 2016-03-30 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A emissão de dióxido de carbono (CO2) pelas atividades humanas vem aumentando desde a revolução industrial. Previsões indicam que ocorrerá um aumento expressivo da concentração atmosférica deste gás nos próximos anos. Este fato deve resultar em alterações metabólicas nas plantas e, por consequência, impactar o setor florestal brasileiro. Os cloroplastos são as organelas-chave na fixação do CO2 e início do particionamento do carbono nas plantas. Alterações na disponibilidade de CO2 podem afetar o metabolismo dessas organelas. O objetivo do presente trabalho foi avaliar se o cultivo de plantas jovens de Eucalyptus urograndis em ambiente enriquecido com CO2 resulta em alterações no proteoma cloroplastidial. Para tanto, primeiramente foram avaliados diferentes métodos de isolamento de cloroplastos quanto aos seguintes parâmetros: morfologia dos cloroplastos observada em microscopia de luz (1); rendimento protéico após isolamento plastidial (2); grau de contaminação por proteínas não cloropastidiais (3); e abundância em número de proteínas identificadas e já descritas como plastidiais (4). Após a definição da melhor metodologia para obtenção do proteoma cloroplastidial, mudas de Eucalyptus urograndis de aproximadamente três meses de idade foram cultivadas sob concentrações atmosféricas controladas de CO2 (400 e 1000 ppm) durante dez semanas. A avaliação do proteoma plastidial, por buscas restringentes contra um banco de dados de sequências protéicas de Eucalyptus grandis, resultou na identificação de 816 proteínas em E. urograndis, das quais 80% já haviam sido descritas como plastidiais. O mapeamento in silico de vias metabólicas resultou na identificação de todas as proteínas envolvidas no ciclo de Calvin-Benson, além da detecção de um aumento discreto, porém significativo na abundância de enzimas-chave: PGK, GAPDH, FBA, FBPase, SBPase e RPI. Embora a avaliação da eficiência quântica do fotossitema II tenha indicado ausência de alteração fotossintética, as plantas tratadas com 1000 ppm de CO2 apresentaram fechamento estomático em resposta à condição ambiental imposta, além da diminuição na área do tecido vascular foliar. Esta é a primeira caracterização do proteoma cloroplastidial do gênero Eucalyptus, cujos resultados indicam que a atmosfera enriquecida com CO2 causou respostas na espécie, incluindo um aumento na abundância de proteínas envolvidas na fixação de carbono. Os resultados apresentados aqui podem auxiliar na compreensão das respostas bioquímicas estimuladas por um aumento na concentração atmosférica de CO2 em plantas do tipo C3, além de contribuir para programas de melhoramento que visem obter plantas adaptadas às condições climáticas futuras. / Carbon dioxide (CO2) emissions from human activities have increased since the industrial revolution. Global projections indicate that there will be a significant increase in the atmospheric concentration of this gas in the coming years. This fact can result in metabolic changes in plants and, consequently, affect the Brazilian forest sector. Chloroplasts are key organelles in carbon fixation and early carbon partitioning in plants. Changes in the availability of CO2 may affect the metabolism of these organelles. The goal of the present study was to assess whether the cultivation of seedlings of Eucalyptus urograndis under a CO2 enriched environment could result in changes in the chloroplast proteome. For this purpose, different chloroplast isolation methods were evaluated to the following parameters: chloroplast morphology observed in bright-field microscopy (1); protein yield after plastid isolation (2); degree of contamination by non-plastidic proteins (3); and abundance in the number of identified proteins described as plastidic (4). After determining the best methodology for the isolation of the chloroplast proteome, E. urograndis seedlings about three months old were grown under CO2 controlled atmospheric concentrations (400 and 1000 ppm) for ten weeks. Evaluation of the plastid proteome, using stringent search against a protein sequence database from Eucalyptus grandis, resulted in the identification of 816 proteins in E. urograndis, from which 80% were already described as plastidic. In silico metabolic pathway mapping resulted in the identification of all proteins involved in the Calvin-Benson cycle and detection of a slight but significant increase in the abundance of key enzymes: PGK, GAPDH, FBA, FBPase, SBPase, and RPI. Although the assessment of the quantum efficiency of photosystem II suggested the absence of changes in the photosynthesis rate, plants treated with 1000 ppm of CO2 presented stomatal closure in response to the imposed environmental condition. A decreased area of the leaf vascular tissue was also detected in young leaves. This is the first characterization of chloroplast proteome of the genus Eucalyptus. Our results indicate that the CO2 enriched atmosphere stimulated metabolic responses, including an increase in the abundance of proteins involved in carbon fixation. Results showed here will assist on the understanding of the biochemical responses stimulated by an increase in the atmospheric CO2 concentration in C3-type plants, and contribute to breeding programs that aim to obtain plants adapted to future climate conditions. / FAPESP: 2014/07454-0
26

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.
27

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.
28

Revisão crítica das regulamentações ambientais à luz das supostas mudanças climáticas globais / Critical review of environmental regulations in the light of the supposed Global climate change

Guilherme Polli Rodrigues 06 September 2012 (has links)
Esta pesquisa avaliou a discussão científica acerca das supostas alterações climáticas globais de origem antrópica sob o embate das correntes cética e aquecimentista, evidenciando que o chamado consenso acerca do tema não existe. Tal análise serviu de base para a avaliação de alguns dos mais importantes tratados ambientais internacionais voltados à proteção climática que originaram diversas regulamentações ambientais nacionais também em função da causa climática. Essa análise, baseada nas verificações prévias, evidenciou que diversas regulamentações nacionais não se sustentam cientificamente e, dessa forma, legalmente, uma vez que partem de um pressuposto inverídico, além do fato de que estas se apresentam danosas aos países em desenvolvimento uma vez que obstam seu desenvolvimento quando apontam como caminho a ideologia ambientalista. / This research evaluated the scientific discussion about the alleged global climate change of anthropogenic origin in the clash of currents global warmers and skepticals, showing that the so-called consensus about the topic does not exist. This analysis formed the basis for the assessment of some of the most important international environmental treaties aimed at climate protection that arose several environmental regulations also due to the climate cause. This analysis, based on previous findings, showed that different national regulations do not hold up scientifically and thus legally, since they start from an assumption untrue, besides the fact that they present themselves harmful to developing countries since they prevent its development indicating the environmentalist ideology as the right path.
29

The effects of salinity and temperature on toxicity of permethrin to pyrethroid-resistant and Wild-type Hyalella azteca

Kent, Logan 01 September 2021 (has links)
Global climate change promotes warming temperatures and altered salinities that pose threats to aquatic ecosystems and species, such as Hyalella azteca. Moreover, these threats to aquatic ecosystems are exacerbated by agricultural, urban, and industrial pesticide runoff. In the state of California in 2012, pyrethroid insecticides were the seventh most applied group by licensed professional applicators for pest control and landscape maintenance. Some species, specifically H. azteca have developed non-target resistance to pyrethroids in California. It is imperative to understand whether the bioenergetic cost of resistance makes H. azteca more susceptible to warming and salinity effects in the presence of contaminants. This research presents an assessment on how multiple stressors can affect the toxicity of permethrin (pyrethroid insecticide) on one Wild-type and two pyrethroid- resistant species of H. azteca, belonging to different clades. A series of 96-h acute toxicity tests exposing animals to a concentration range of permethrin were performed with compounding stress from temperatures (18, 23 and 28 °C) and salinities (0.2, 1.0, and 6.0 practical salinity units [PSU]). Findings indicate resistant H. azteca cultured in pyrethroid-free settings have maintained resistance to permethrin over time, whereas the wild-type population did not develop any resistance over the course of experimentation. For resistant H. azteca, changes in salinity and temperature both increased and decreased survival of H. azteca exposed to permethrin. Between the two resistant clades, not only was survival affected, but the average slope of the dose-response curve was significantly different (p < 0.05); clade D was more susceptible to pyrethroids when coping with warming and higher salinity than clade C., Differential susceptibility potentially indicates that distinct resistance mutations confer a difference in the potency and mode of toxic action. The results provide insight to how changes posed by climate change, coupled with pyrethroid pesticides could be detrimental to this species, and conversely, how in some scenarios, changes to temperature and salinity might actually benefit the survival of H. azteca. These findings further indicate the importance of considering global climate change effects into risk assessments of emerging and legacy use contaminants.
30

Projevy chaotického chování v pozorovaných a simulovaných řadách klimatických veličin / Manifestation of chaotic behavior in observed and simulated series of climatic variables

Skořepa, Jan January 2014 (has links)
Diplomová práce se věnuje analýze chaotického chování v řadách (pseudo)pozorovaných a simulovaných klimatických veličin. Nejprve objasňuji ně- které základní teoretické pojmy související s dynamickými systémy. Potom se zabývám zp·soby rekonstrukce fázového prostoru a uvedu metody odhadu kore- lační dimenze a největšího Ljapunovova exponentu. V praktické části se zabývám pr·měrnou denní teplotou z reanalýz ERA-40 a reanalýzami NCEP/NCAR v tlakových hladinách 850 a 500 hPa z let 1960-2000. Nejprve zkoumám podrobně jednu vybranou řadu. Používám např. metodu falešných soused· a určuji míru vzájemné informace. Zjiš'uji, že korelační dimenze nenabývá konkrétní hodnotu. Pro analýzu celých tlakových hladin vyvíjím program, který počítá divergenci blízkých trajektorií, což je postup používaný při výpočtu největšího Ljapunovo- va exponentu. Tento program postupně aplikuji na oblasti velikosti 20◦ × 30◦ kterými je pokryta celá zeměkoule. Postupně ukazuji a srovnávám výsledky pro reanalýzy v obou tlakových hladinách s ročním chodem a odečteným ročním cho- dem. Tuto metodu aplikuji na výstupy globálních klimatických model· HadCM3 a MPI-ESM-MR v hladině 500 hPa. Podobnou analýzu ještě uskutečňuji u jed- nodimenzionálních řad teploty u reanalýz a u model·. Výsledky opět vizuálně srovnávám. 1

Page generated in 0.118 seconds