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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.
111

Épidémiologie du syndrome reproducteur et respiratoire porcin dans deux régions de densités porcines différentes au Québec

Lambert, Marie-Ève 06 1900 (has links)
No description available.
112

Beteenden hos befruktad allmän dammussla (Anadonta anatina) i en stressande miljö : Kritiskt temperaturmaximum (KTM) i relation till befruktning / Behaviors of fertilized common duck mussel (Anodonta anatina) in a stressful environment : Critical temperature maximum (CTM) in relation to fertilization

Blad, Sara January 2022 (has links)
Den globala uppvärmningen förväntas öka jordens medeltemperatur framledes, vilket innebär att nederbördmönster kommer att ändras till följd av torka och översvämningar. Detta kommer att innebära ett ökat hot för många sötvattensmusslor, som redan är en av de mest hotade grupperna i världen. Temperaturen är en essentiell abiotisk faktor som styr fortplantning, tillväxt och överlevnad. Att mäta kritiskt temperaturmaximum (KTM) är en metod som är framtaget för att användas för att få en förståelse huruvida organismer tål värmeökningar. Under processen sker en gradvis uppvärmning under ett snabbt förlopp, och vid uppnådd KTM utsätts organismen för en extrem stress. Vid flertalet utförda inventeringar i Sverige har uteblivna föryngringar av sötvattensmusslor upptäckts. Syftet är därav att vi i detta experiment ska se om det råder skillnader i värmekänslighet hos befruktade musslor kontra obefruktade musslor. Hypoteserna är (1) befruktad dammussla når KTM tidigare än obefruktad dammussla och (2) befruktad dammusslas fot är utan rörelsekontroll vid en lägre temperatur än hos de obefruktade.  Allmän dammussla (Anodonta anatina) användes till experimentet, då den är helt utesluten ur den internationella rödlistan och vanligt förekommande i svenska sötvatten. Musslorna, vilka plockades i Alsterälven, acklimatiserades i fyra dygn i 10 °C. Under experimentet värmdes vattnet kontinuerligt med 0,3 °C/min, tills KTM hade uppnåtts. Resultatet för hypotes (1) visar att befruktade dammusslor hade ett signifikant högre KTM än obefruktade (t-test, p=0,039), vilket är tvärtemot min hypotes. Resultat för hypotes (2) visar ingen skillnad mellan grupperna (t-test, p=0,54). Varför befruktade musslor uppnådde ett högre KTM skulle kunna bero på att glochidierna stört filtreringen, så pass att gälfunktionen stärkts, vilket lett till att de klarar att hålla igång filtreringen och sin egen metabolism vid högre temperaturer. Mer studier behövs för att få en ökad förståelse över musslors känslighet av temperaturförändringar. / Global warming is expected to increase the earth's average temperature in the future, which means that precipitation patterns will change as a result of droughts and floods. This will pose an increased threat to many freshwater mussels, which are already one of the most endangered groups in the world. Temperature is an essential abiotic factor that controls reproduction, growth and survival. Critical temperature maximum (CTM) is a method that has been developed to be used to gain an understanding of whether organisms can tolerate heat increases. During the process, a gradual heating takes place during a rapid process, and when CTM is reached, the organism is exposed to extreme stress. In the majority of inventories carried out in Sweden, missing rejuvenations of freshwater mussels have been discovered. The purpose is that in this experiment we will see if there are differences in heat sensitivity of fertilized mussels versus unfertilized mussels. The hypotheses are that (1) fertilized mussels reaches their CTM earlier than unfertilized mussels and (2) fertilized mussels relax their foot completely at a lower temperature than the unfertilized mussels. The result for hypothesis (1) shows that fertilized mussels had a significantly higher CTM than unfertilized (t-test, p = 0.039), which is contrary to my hypothesis. Results for hypothesis (2) show no difference between the groups (t-test, p = 0.54). The common duck mussel (Anodonta anatina) was used for the experiment, as it is not in the international red list and is commonly found in Swedish freshwaters. The mussels, which are from the Alsterälven River, were acclimatized for four days in 10 °C river water before the experiment. During the experiment, the water was continuously heated at 0.3 °C/min, until the CTM was reached. Why fertilized mussels achieved a higher CTM could be due to the fact that the glochidians disrupted the filtration, so much so that the gill function was strengthened, which led to them being able to keep the filtration going and their own metabolism at higher temperatures. More studies are needed to gain an increased understanding of mussels' sensitivity to temperature changes.
113

Potential of waste-derived VFAs-bearing effluents as an external carbon source for MBBR denitrification of domestic wastewater / Potentialen av avfallshärledda VFA-bärande substrat som en extern kolkälla för MBBR-denitrifiering av avloppsvatten

Manafi Khosroshahi, Seyed Reza January 2022 (has links)
In conventional wastewater treatment plants, methanol, ethanol, and acetate are used as carbon source for the denitrification process in the biological nutrient removal. However, growing concern regarding economical costs and carbon footprints from the fossil-based production of these chemicals have forced the companies to look for other alternatives. VFAs have shown a great potential in replacing the conventionally used carbon sources. If implemented this will result in lower chemical cost and a drastic decrease in carbon footprint as well as striving WWTPs towards sustainable development. In this work denitrification has been analysed using different variations of VFAs such as fermented potato protein liquor, food waste and chicken manure VFA. This was done using a basic laboratory setup of a denitrification reactor which used basic stirring agitation and nitrogen purging to ensure anoxic conditions. Nutrients and excess sCOD were added to ensure the highest denitrification rates. The denitrifying biomass was collected at Gryaab AB in the form of k1-carriers making this process a MBBR. The most influential characteristic of the VFAs is the distribution of the acids in the VFA effluent. Butyric acid along with caproic acid showed the best potential for efficient denitrification. The possibility of concentration of VFA effluent showed a high potential when using a nanofiltration system. A C/N ratio of 4.5 conventionally used when methanol is added showed to be the most optimal condition for VFA addition. The combination of VFAs together with conventional used carbon sources showed the best potential in denitrification efficiency proving to be as good or even better than pure synthetic ones. VFAs effluents showed the best potential in removing the intermediate nitrite from the wastewater at high rates. Overall, VFAs shown a great potential for replacing conventionally used carbon sources, demonstrating the potential of substitution, which if implemented will result in lower carbon footprint and a strive towards sustainable development.
114

Effets du changement climatique sur les écosystèmes littoraux de la mer Méditerranée nord-occidentale : étude de la relation entre les conditions de température et la réponse biologique pendant les événements de mortalité massive

Crisci, Carolina 31 October 2011 (has links)
[résumé trop long] / [résumé trop long]
115

Avaliação do metabolismo oxidativo em Pitcairnia encholirioides L. B. Sm. (Bromeliaceae) in vitro e ex vitro e sob desidratação

Resende, Cristiano Ferrara de 05 March 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-23T12:29:44Z No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) / Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: Primeira letra de cada palavra chave em maiúsculo, a não ser que seja nome próprio on 2016-07-02T11:34:23Z (GMT) / Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-04T10:21:07Z No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:11:52Z (GMT) No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) / Made available in DSpace on 2016-07-13T16:11:53Z (GMT). No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) Previous issue date: 2012-03-05 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Bromeliaceae é uma família essencialmente neotropical, cujos representantes são muito utilizados para fins paisagísticos. Uma das principais fontes de abastecimento do mercado consumidor de bromélias é o extrativismo o que, associado à destruição do ambiente natural, tem levado a perdas irreparáveis na biodiversidade da família, especialmente na Mata Atlântica, onde cerca de 40% das espécies encontram-se sob alguma categoria de ameaça. Pitcairnia encholirioides L. B. Sm. é uma espécie “criticamente em perigo” de extinção, sendo conhecida somente uma população dessa espécie, com cerca de 900 indivíduos, encontrada em 2004 em um afloramento rochoso muito degradado e sujeito ao fogo e ao pisoteio de animais, no município de Santa Maria Madalena, RJ. A utilização das técnicas de micropropagação pode reverter os riscos de extinção garantindo taxas elevadas de multiplicação, fornecendo material necessário ao mercado consumidor, evitando, dessa forma, o extrativismo das plantas nos seus locais de origem. A instalação e a conservação in vitro de bancos de germoplasma possuem especial importância, garantindo a sobrevivência de espécies raras e/ou endêmicas e fornecendo plantas para iniciativas de reintrodução. A etapa final da micropropagação é a aclimatização ex vitro, realizada após os procedimentos de multiplicação e enraizamento in vitro. A aclimatização é um período crítico para as plantas devido à perda de água, o que causa estresse hídrico e, como consequência, estresse oxidativo, podendo provocar problemas metabólicos e perdas elevadas. No presente trabalho, Pitcairnia encholirioides foi cultivada in vitro por 150 dias em meio de cultura adicionado de dois reguladores de crescimento (GA3 ou ANA), além de duas concentrações de sacarose (15 ou 30 g L-1) e sob dois tipos de vedação dos tubos de ensaio (vedação hermética com tampas e filme de PVC ou vedação com tampas que permitiam trocas gasosas), totalizando 8 tratamentos, período após o qual as plantas foram transferidas para condições ex vitro, em casa de vegetação, permanecendo por mais 180 dias. Dois desses tratamentos foram selecionados para as análises de desidratação, quando suas plantas foram submetidas a 30, 42 ou 54 dias sem irrigação, além do controle irrigado periodicamente, sendo posteriormente reidratadas durante 90 dias. Após os períodos de cultivo in vitro e permanência das plantas em casa de vegetação, foram realizadas análises dos conteúdos de prolina, proteínas totais, atividades das enzimas do metabolismo antioxidativo SOD, CAT, POD e PPO, além 2 dos teores de pigmentos fotossintetizantes. Além desses parâmetros, após desidratação e reidratação foram também avaliados os teores de carboidratos. De maneira geral, o cultivo in vitro em meio adicionado da menor concentração de sacarose e em tubos vedados hermeticamente se mostrou prejudicial, o que foi evidenciado pelo menor acúmulo de prolina, aumentos nas atividades das enzimas antioxidativas e menor acúmulo de pigmentos fotossintéticos. Após o período de aclimatização, não foram encontradas diferenças entre os tratamentos para a maioria dos parâmetros analisados, ou os dados oscilaram de maneira a não permitir uma generalização quanto aos efeitos residuais da sacarose, do tipo de tampa e dos reguladores de crescimento utilizados durante o cultivo in vitro. No período em que as plantas foram submetidas à desidratação progressiva, houve maior acúmulo de prolina e proteínas solúveis totais, além de aumento nos teores de pigmentos fotossintéticos nos tecidos provenientes de plantas cultivadas in vitro em meio contendo 30 g L-1 de sacarose e GA3. Houve também, em geral, queda mais acentuada nas atividades das enzimas em meio suplementado com a menor concentração de sacarose e ANA, além de oscilações nos teores de pigmentos. As relações entre os pigmentos sofreram leve redução em ambos os tratamentos, e os teores de carboidratos solúveis totais, sacarose, açúcares redutores e amido aumentaram com o prolongamento do estresse. Após a reidratação, todas as plantas demonstraram elevada capacidade de recuperação, apresentando em todas as análises realizadas valores muito similares aos das plantas do controle, não submetidas à desidratação. Os resultados obtidos no trabalho permitem concluir que o cultivo in vitro em meio adicionado de 30 g L-1 de sacarose e em tubos de ensaio que permitem trocas gasosas é o mais apropriado para plantas de P. encholirioides. Ademais, a concentração de sacarose adicionada ao meio de cultura também influencia o desenvolvimento das plantas após aclimatização, sendo encontrados melhores resultados em plantas cultivadas nos meios de cultura suplementados com a maior concentração desse carboidrato. Acredita-se que as plantas cultivadas nessas condições apresentariam maior capacidade de sobrevivência ao transplantio e maior resistência a períodos prolongados de estresse hídrico, aos quais, frequentemente, estão submetidas no ambiente natural. / Bromeliaceae is essentially a neotropical family, whose representatives are widely used for landscaping. One major source of supply for the consumer market is the extraction, which coupled with the destruction of the natural environment, has led to irreparable losses in biodiversity of the family, especially in the Atlantic Forest, where about 40% of bromeliad species are under some category of threat. Pitcairnia encholirioides L. B. Sm. is a critically endangered species. In 2004, a unique population of this species was found, with about 900 individuals in a very degraded rocky outcrop, subject to fire and trampling by animals, located in Santa Maria Madalena, RJ. The use of micropropagation can guarantee high multiplication rates, providing necessary material for the consumer market, effectively obviating the extraction of plants in their places of origin. In addition, installation and in vitro conservation of germplasm banks have special importance, ensuring the survival of rare species and/or endemic and providing micropropagated plants for reintroduction initiatives. Following the procedures of in vitro multiplication and rooting, the final stage of micropropagation is the ex vitro acclimatization, a critical period for the plants due to water loss, which causes water stress and, consequently, oxidative stress, which can cause metabolic problems and high losses. In this study, Pitcairnia encholirioides was grown for 150 days in vitro in a culture medium supplemented with two growth regulators (GA3 or NAA), and two concentrations of sucrose (15 or 30 g L-1) in two types of sealing of test tubes (hermetic seal with lids and PVC film and seal with lids that allowed gas exchange), totaling eight treatments, after which the plants were transferred to ex vitro conditions in a greenhouse, staying for more than 180 days. Two of these treatments were selected for analysis of dehydration when their plants were subjected to 30, 42 or 54 days without irrigation, apart from control irrigated periodically, being subsequently rehydrated for 90 days. After periods of in vitro cultivation and maintenance of the plants in the greenhouse, they were analyzed for proline content, total protein, activities of antioxidant metabolism enzymes SOD, CAT, POD and PPO, besides the content of photosynthetic pigments. Apart from these parameters, after dehydration and rehydration, levels of carbohydrates were also assessed. In general, the in vitro culture in medium containing the lowest concentration of sucrose and hermetically sealed tubes proved to be harmful, which was evidenced by lower levels of proline, increased 4 activity of antioxidant enzymes and lower accumulation of photosynthetic pigments. After the acclimatization period, no differences were found between treatments for most parameters, or data varied so as to not allow a generalization about the residual effects of sucrose, the type of cover and of the growth regulators used in the in vitro cultivation. During the period in which the plants were subjected to water stress, higher accumulation of proline and total soluble proteins occurred, and also increased levels of photosynthetic pigments in tissues from plants grown in vitro in medium containing 30 g L-1 sucrose and GA3. There was also, in general, sharper decrease in enzyme activity in medium with the lowest concentration of sucrose and NAA, as well as fluctuations in pigment. Relations between pigments suffered slight reduction in both treatments, and total soluble carbohydrates, sucrose, reducing sugars and starch increased with increasing stress. After rehydration, all plants showed high resilience, presenting for all analyzes values very similar to those of control plants not subjected to dehydration. The results indicate that the in vitro culture in medium supplemented with 30 g L-1 sucrose and tubes that allow gas exchange are the most appropriate. Moreover, the concentration of sucrose added to the culture medium also influences the development of plants after acclimatization, with best results found in plants grown in media supplemented with higher amount of this carbohydrate. It is believed that plants grown under these conditions would have higher capacity of resistance to transplanting and could survive for prolonged periods of water stress, which are often subjected in the natural environment.
116

Effect of (vesicular-) arbuscular mycorrhiza on survival and post vitro development of micropropagated oil palms (Elaeis guineensis Jacq.) / Wirkung der vesikulär-arbuskulären Mykorrhiza auf die Überlebensrate und die post vitro Entwicklung von Ölpalmklonen (Elaeis guineensis Jacq.)

Schultz, Claudia 22 November 2001 (has links)
No description available.

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