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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.
71

Resposta fisiológica, qualidade da carne e expressão gênica no músculo esquelético de frangos de corte sob estresse por calor que receberam antioxidantes na dieta /

Zeferino, Cynthia Pieri, 1981- January 2012 (has links)
Orientador: Ana Silvia Alves Meira Tavares Moura / Banca: José Roberto Sartori / Banca: Dirlei Antonio Berto / Banca: Luiz Lehmann Coutinho / Banca: José F. M. Mendes / Resumo: A temperatura ambiente elevada representa o principal fator limitante do desenvolvimento da produção avícola em regiões de clima quente. O objetivo do trabalho foi verificar se a dieta suplementada com vitaminas C e E, seria capaz de neutralizar, ou reduzir, os efeitos do estresse por calor, aplicado dos 28 aos 42 dias de idade, sobre a resposta fisiológica, o desempenho, rendimento de carcaça e qualidade da carne de frangos. Foram utilizados 384 frangos de corte machos distribuídos num delineamento inteiramente casualizado, com arranjo fatorial 2 x 3 (com e sem suplementação da dieta com vitaminas e temperaturas ambientais associadas ao pair-feeding) e 16 repetições. As aves foram mantidas em termoneutralidade até os 28 dias. A partir desta idade, foram alojadas em grupos de quatro por gaiola, em três salas climatizadas: duas termoneutras (22,6 e 22,5ºC) e uma de estresse por calor (31,7ºC). Metade das aves recebeu dieta suplementada com vitaminas C (536 mg/kg) e E (127 mg/kg). Na sala de estresse por calor as aves tiveram livre acesso à ração; nas salas termoneutras metade das aves recebeu ração à vontade e a outra metade recebeu quantidade limitada, no sistema pair-feeding. Foram avaliados a temperatura retal e da superfície da pele e características de desempenho, rendimento de carcaça e qualidade instrumental da carne. As análises de qualidade de carne foram realizadas no músculo pectoralis major (peito) 24 horas após o abate. A suplementação da dieta com vitaminas C e E não foi capaz de neutralizar, nem de reduzir, os efeitos negativos do estresse por calor sobre as características de desempenho, rendimento de carcaça e qualidade de carne das aves. A semelhança nos resultados de desempenho entre aves em estresse por calor e em pair-feeding sugere que a queda no desempenho sob estresse por calor deveu-se, principalmente, à redução no consumo de alimentos / Abstract : Elevated ambient temperature represents the main limiting factor for the development of chicken production in hot climate regions. The objective of this study was to evaluate if the diet supplemented with vitamins C and E would be able to reduce, or neutralize the negative effects of heat stress applied between 28 and 42 days of age, on the physiological response, performance, slaughter yield and meat quality of chickens. A total of 384 male broiler chickens were assigned to a completely randomized design, with a 2 x 3 factorial arrangement (diet with or without vitamins supplementation and ambient temperatures associated with pair-feeding) and 16 replications. The chickens were kept in thermoneutral conditions up to 28 days of age. From this age and on, were housed in groups of four per cage, in three environmentally controlled chambers: two were thermoneutral (22,6 e 22,5ºC) and one for heat stress (31,7ºC). Half the chickens were offered a diet supplemented with vitamins C (536 mg/kg) and E (127 mg/kg). In the heat stress chamber, the chickens had free access to the feed; in the thermoneutral chambers half the chickens had free access to the feed and the other half received a limited amount, in a pair-feeding system. Rectal and body surface temperatures and performance, slaughter yield and meat quality traits were evaluated. Meat quality analyses were performed in the pectoralis major muscle 24 hours after slaughter. Diet supplementation with vitamins C and E were not able to neutralize, neither to reduce, the negative effects of heat stress on the performance, slaughter yield and meat quality traits. The similarity of performance results between the chickens submitted to heat stress and pair-feeding, suggested that the reduction in performance under heat stress were due mainly to the drop in feed consumption / Doutor
72

Influência da variação sazonal da temperatura e umidade do solo na germinação de sementes de espécies do cerrado : Xylopia aromatica (Lam.) Mart. (Annonaceae), Banisteriopsis variabilis B. Gates (malpighiaceae) e Vochysia tucanorum Mart. (Vochysiaceace) /

Locardi, Bruna. January 2011 (has links)
Orientador: Massanori Takaki / Banca: Edvaldo Aparecido Amaral da Silva / Banca: Antonio Carlos Silva de Andrade / Resumo: A diversidade de estratégias reprodutivas e de germinação de sementes da flora do cerrado brasileiro é consequência da heterogeneidade fisionômica e da sazonalidade. Essas estratégias são adaptativas para o momento onde temperatura e umidade permitam o estabelecimento de uma nova geração de plantas. O momento de dispersão e o controle fisiológico da aptidão a germinar são estratégias para a sincronização com a estação chuvosa. A sincronização fisiológica é feita pela flutuação da dormência a partir de sinais ambientais, e seus principais sinalizadores são os hormônios vegetais ABA (inibidor da germinação e agente do aprofundamento da dormência) e GA (promotor da germinação). Por nível de dormência entende-se um estado de estabilidade da semente onde certas condições ambientais podem promover a germinação, inibi-la ou ainda aprofundar esse nível a um estado sensível a outras condições ambientais. Buscamos compreender a influencia da variação da temperatura e umidade de solo pos dispersão na germinação de sementes X. aromatica, B. variabilis e V. tucanorum. Para inferir a flutuação hormonal causada pela sazonalidade, a sensibilidade das sementes a GA4+7 e fluridona e água foi acompanhada pós enterrio. As áreas experimentais foram duas, a Reserva Experimental de Mogi-Guaçu e o Jardim Experimental da UNESP Rio Claro. Os dados de temperatura, umidade do solo foram registrados a cada na profundidade de 5 cm, mesma do enterrio. A viabilidade inicial das sementres das três espécies é acima de 75%, mas a germinabilidade de B. variabilis é de 30%. As sementes de V. tucanorum e B. variabilis têm embriões morfologicamente maduros já as sementes de X. aromatica são morfo-fisiologicamente dormentes. Sendo pós-dispersão, sensíveis a GA e perdendo a sensibilidade com o aprofundamento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A great number of reproduction and germination strategies are found in plants of the neotropical savannas (Brazilian Cerrados) due to its physiognomic diversity and seasonality. That allows a new generation establishment when temperature and moisture are less harsh than the dry winter. Dispersion time and physiological control of germination ability are regular strategies used to synchronize it with rainy season. Synchronization is regulated by changes on dormancy level by environmental cues, mainly controlled by ABA (germination inhibitor and dormancy agent) and GA (germination promoter). Dormancy level is a seed stable state in which environmental cues can promote or inhibit germination or also change it into a different level more sensitive to other environmental condition. Observing X. aromatica, B. variabilis and V. tucanorum seeds morphology, germination and viability, after dispersion and burial and incubated on water, GA4+7 .Its in situ germination was observed at 2 burial sites (Reserva Experimental de Mogi-Guaçu (MG) and Jardim Experimental da UNESP Rio Claro(JD)) after dispersion, combined with soil temperature and moisture at 5cm deep, and environmental data we search to comprehend how seasonality affects the seed's dormancy levels, germination, mortality and hormonal sensitivity. All the three species have over 75% viable embryos, although B. variabilis germinability is less than 30%. X. aromatica seeds are morpho physiolocally dormant, being sensible to GA after dispersion and losing this sensitivity by dormancy enhanced by the burials and alternating high amplitude of temperature followed by days with amplitude lower than 10°C break these deep dormancy and on moisture soil, allows the embryo development and germinate. Lower moisture content delays the embryo... (Complete abstract click electronic access below) / Mestre
73

Avaliação da qualidade de cultivares de alface submetidas a distintos métodos de resfriamento / Evaluation quality of lettuce cultivars subjected to different cooling methods : Rodolpho Cesar dos Reis Tinini

Tinini, Rodolpho César dos Reis, 1987- 02 June 2012 (has links)
Orientador: Barbara Janet Teruel Mederos, Paulo Ademar Martins Leal / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-20T03:40:17Z (GMT). No. of bitstreams: 1 Tinini_RodolphoCesardosReis_M.pdf: 2113855 bytes, checksum: bf35d4b21243161421a237dd2edcc622 (MD5) Previous issue date: 2012 / Resumo: A hortaliça folhosa mais consumida e produzida no Brasil é a alface (Lactuca sativa L.) e seu consumo vem crescendo a cada ano devido a uma tendência da população mundial em adquirir hábitos de vida mais saudáveis. Existem diferentes métodos de resfriamento para conservação pós-colheita, já utilizados e aplicados em olerícolas, porém não se tem conhecimento sobre seus efeitos e benefícios para a alface. O objetivo deste estudo foi avaliar a aplicação de diferentes métodos de resfriamento e sua adequação para diferentes variedades de alface. Os tipos de alfaces analisadas foram a repolhuda crespa ou americana, a solta crespa, a repolhuda lisa e a solta lisa, adquiridas de um produtor da região de Campinas-SP. Foram avaliados três métodos de resfriamento seguidos de acondicionamento em câmara fria a 5ºC: resfriamento com ar forçado (com controle da umidade relativa do ar e sem controle da umidade relativa do ar), resfriamento evaporativo em túnel (nebulização e ventilador-meio poroso) e resfriamento com água fria (imersão e aspersão), sendo que o controle consistiu apenas no acondicionamento do produto em câmara fria a 5ºC, e os parâmetros físico-químicos (pH, ácido ascórbico, clorofila e perda de massa). O delineamento experimental foi inteiramente casualizado (DIC) com cinco repetições por tratamento, observando-se a interação entre os métodos de resfriamento e tempo de armazenamento, e estes parâmetros foram submetidos à análise estatística multivariada aplicando-se a análise de componentes principais. Conclui-se que o melhor método para o resfriamento de alface é o do ar forçado com umidificação, pois equilibra eficiência de resfriamento e menor degradação do produto. O resfriamento da alface pelo método evaporativo apresenta uma lenta retirada de calor especifico, desfavorecendo a manutenção da vida útil do produto, assim como o método por água fria que causa acúmulo de água no interior do produto facilitando as reações de deterioração. Com relação à análise de custo energético, o resfriamento de alface pelo método ar forçado se torna mais interessante em termos de aplicabilidade e manutenção da qualidade do produto, mesmo apresentando um maior custo se comparado ao resfriamento de alface pelo método evaporativo / Abstract: The leafy vegetable most consumed and produced in Brazil is the lettuce (Lactuca sativa L.) and its consumption is growing up every year due a tendency of world population to acquire healthier lifestyle. There are different cooling methods for post-harvest quality, already used and applied in vegetable crops, but there is no knowledge about yours effects and benefits for lettuce. The objective of this study was evaluating the application of different cooling methods and their suitability for different varieties of lettuce. The types of lettuce analyzed were "repolhuda crespa" ou "americana", a "solta crespa", a "repolhuda lisa" e a "solta lisa", acquired from a region producer in Campinas-SP. We evaluated three cooling methods followed to a storage in cold chamber at 5 ° C: forced air cooling (with relative humidity control and no relative humidity control), evaporative cooling tunnel (misting and porous-fan) and hydroccoling (immersion and spray), and control consisted in the product cold storage at 5°C, was evaluate the physic-chemical parameters (pH, ascorbic acid, chlorophyll and weight loss). The experimental design was completely randomized, with five replicates per treatment, observing the interaction between cooling methods and storage time, and these parameters were subjected to multivariate statistical analysis with applying the principal component analysis. It is concluded that the best method for cooling lettuce is forced air with humidification it balances cooling efficiency and less degradation of the product. The cooling of the lettuce by evaporative method has a slower specific heat removed, which does not favor the maintenance product shelf-life, as well as the hydrocooling causes water accumulation in the product facilitates the degradation reactions. Regarding the analysis of cost energy, the cooling lettuce by forced air method becomes more interesting in terms of applicability and maintenance at product quality, even with a higher cost compared to the cooling of lettuce evaporative method / Mestrado / Tecnologia Pós-Colheita / Mestre em Engenharia Agrícola
74

Modifiable Risk in a Changing Climate: Linking household-level temperature, humidity, and air pollution to population health

Quinn, Ashlinn Ko January 2016 (has links)
Background: This dissertation comprises research conducted on two distinct projects. Project I focuses on the connection between household air pollution (HAP) from cooking with biomass fuels and blood pressure (BP); this research is situated in the context of a large randomized trial of a cookstove intervention in Ghana, West Africa. The setting of Project II, meanwhile, is the residential environment of New York City, where we explore temperature and humidity conditions in homes and relate these conditions to summertime heat wave risk and to the survival and transmission of respiratory viruses in the winter. Although these projects are quite distinct, each relates to the complex relationship between climate change and health. Reducing HAP to improve health (the focus of Project I) will simultaneously reduce climate change through a reduction in emissions of short-lived climate pollutants into the atmosphere. Meanwhile, furthering our understanding of heat and humidity levels inside urban residences (the focus of Project II) is crucial to our ability to protect health in light of projections for a changing climate. Domestic activities associated with heating, cooling, and cooking are thus very relevant both to human health and to climate change mitigation and adaptation. Objectives and Methods: Our overall objective for Project I was to investigate exposure- response relationships between HAP and BP in a cohort of pregnant women taking part in the Ghana Randomized Air Pollution and Health Study (GRAPHS). We first explored this association in a cross-sectional study (Chapter 1), in which we used 72-hour personal monitoring to ascertain levels of exposure among the GRAPHS women to carbon monoxide (CO), one of the pollutants emitted by traditional wood-fed cooking fires. These exposure data were collected at enrollment into the GRAPHS study, prior to the initiation of cooking with improved cookstoves. We investigated the association between these “baseline” CO exposure levels and the women’s blood pressure at enrollment into GRAPHS. A limitation of this study was that BP was only measured once. We followed this with a second study of 44 women drawn from the same cohort (Chapter 2), for whom we designed BP protocols using 24-hour ambulatory blood pressure monitoring (ABPM), the current gold standard for clinical diagnosis of hypertension. As we were not aware of any prior research in Africa that had employed ABPM, we also designed a parallel BP protocol using home blood pressure monitoring (HBPM) equipment for comparison with ABPM. The use of ABPM with concurrent personal CO monitoring enabled us to investigate hourly associations between CO exposure and changes in BP. We also evaluated BP in these women both before and after the cookstove intervention; this allowed us to investigate whether any changes in BP were associated with switching to an improved cookstove. Our objectives for Project II were to understand the distribution of temperature and humidity conditions in a range of New York City homes during the summer and winter seasons, to evaluate the impact of structural and behavioral factors (e.g. building size, use of air conditioning, and use of humidifiers) on these conditions, and to build models that could help predict indoor conditions from more readily available outdoor measurements. We conducted this research in two ways. We first analyzed a set of indoor temperature and humidity measurements that were collected in 285 New York City apartments during portions of summers 2003-2011 and used these data to simulate indoor conditions during two heat wave scenarios, one of which was more moderate and the other of which was more extreme (Chapter 3). Second, we designed and conducted a new study in which temperature and humidity were monitored in a set of 40 NYC apartments between 2013 and 2015 (Chapters 4-6). This second study enabled us extend our research into the winter season, and also to explore how factors such as air conditioning and humidifier use impacted indoor temperature and humidity. We also investigated relationships between the monitored conditions, self-reported perceptions of the indoor environment, and symptoms that were experienced among household members. Results: In the cross-sectional analysis of CO and BP in the GRAPHS cohort (Chapter 1), we found a significant positive association between CO exposure and diastolic blood pressure (DBP): on average, each 1 ppm increase in exposure to CO was associated with 0.43 mmHg higher DBP [0.01, 0.86]. A non-significant positive trend was also observed for systolic blood pressure (SBP). In our study of the acute relationship between CO exposure and BP (Chapter 2), we determined that peak CO exposure (defined as above the 90th percentile of the exposure distribution, or an average of 4.1ppm) in the two hours prior to BP measurement was associated with elevations in hourly systolic BP (4.3 mmHg [95% CI: 1.1, 7.4]) and diastolic BP (4.5 mmHg [95% CI: 1.9, 7.2]), as compared to BP following lower CO exposures. We also observed a non-significant trend toward lower BP following initiation of cooking with an improved cookstove. Lastly, we demonstrated that ABPM was a feasible and well-tolerated tool for BP assessment in a rural West African setting. For Project II in New York City, we first determined that there was a great deal of variability in indoor summer heat index (HI) between homes in association with similar outdoor conditions, and that this variability increased with increasing outdoor heat (Chapter 3). Our simulation of a moderate heat wave led us to conclude that the hottest 5% of the homes would reach peak indoor heat index (HI) values of 39°C. In a more extreme heat wave simulation, HI in the hottest 5% of homes reached a peak of 41oC and did not drop below 34oC for the entire nine- day simulated heat wave period. Our second indoor monitoring study yielded the following findings: in the summer season (Chapter 4), we found significant differences in indoor temperature and heat index according to the type of air conditioning (AC) in the home. Homes with central AC were the coolest, followed by homes with ductless AC, window AC, and no AC. Apartments on the top floor of a building were significantly hotter than other apartments regardless of the presence of AC. During the winter season (Chapter 5), median vapor pressure in our sample of apartments was 6.5mb. Comparing humidity levels in the apartments to a threshold of 10mb vapor pressure that has been proposed as protective against influenza virus transmission, levels of absolute humidity in the homes remained below this threshold for 86% of the winter: a total of over three months. Residential use of humidifiers was not associated with higher indoor humidity levels. Larger building size (above 100 units) was significantly associated with lower humidity, while the presence of a radiator heating system was non-significantly associated with higher humidity. Lastly, perceptions of indoor temperature and measured temperature were significantly associated in both the summer and the winter (Chapter 6), while sleep quality was inversely related to measured indoor temperature in the summer season only. Reports of heat- stress symptoms were associated with perceived, but not measured, temperature in the summer season. Conclusions: The work presented in this dissertation adds to a growing body of evidence on the importance of exposures in the domestic environment to health and well-being. The research reported here on household air pollution in Ghana documents an exposure-response relationship between air pollution from cookstoves and elevations in blood pressure, on both a chronic and an acute basis. As elevated BP is a known risk factor for cardiovascular disease (CVD), our research provides support for a plausible factor linking HAP exposure to CVD. Meanwhile, our research on temperature and humidity in New York City residences provides concrete data to supplement the very slim literature to date documenting these conditions in the home environment, where Americans spend over half their time. We conclude, first, that AC may not be fully protective against summertime heat risk, and second, that the levels of humidity we observed in residential environments are consistent with levels that have been shown to promote enhanced survival and transmission of respiratory viruses in experimental settings. We suggest that interventions that can reduce exposure to household air pollution and excess indoor heat can also mitigate climate change, and that with thoughtful planning we can improve health at the same time as we foster resiliency in the face of a changing climate.
75

Condições de estresse e conforto térmico em fábrica de pré-moldado em Ponta Grossa - PR / Conditions of heat stress and thermal comfort in precast industry in Ponta Grossa - PR

Galvan, Tanise Fuckner de Oliveira 28 February 2018 (has links)
O estresse térmico é um risco reconhecido a que os trabalhadores de várias indústrias estão expostos. De forma a verificar a condição de estresse e também conforto térmico na fábrica de pré-moldado em concreto, foi realizada uma pesquisa na qual as variáveis ambientais e pessoais foram obtidas através de medições e questionários. A avaliação preliminar do estresse térmico foi realizada pela escala HSSI, a qual indicou a não existência do mesmo nessa fábrica. Foi efetuada a avaliação do ambiente, através dos índices IBUTG e PHS, que ratificaram a não existência do estresse térmico. Como não houve a incidência do estresse térmico, o ambiente foi avaliado com relação ao conforto térmico, nas medições em que o índice PMV era aplicável, e foi calculado o índice PET. Através do cálculo do índice do PMV, verificou-se que em apenas uma medição o ambiente pode ser considerado confortável, nas demais o ambiente é considerado desconfortável termicamente. Os resultados do índice PET, demonstram que na maioria das medições também ficou caracterizada o desconforto térmico. / Heat stress is a recognized risk that workers in various industries are exposed. In order to verify the stress condition and also thermal comfort in the precast concrete factory, a research was carried out in which the environmental and personal variables were obtained through measurements and questionnaires. The preliminary evaluation of the heat stress was performed by the HSSI scale, which indicated the absence of heat stress in this factory. To confirm this conclusion, the evaluation of the environment was carried out through the IBUTG and PHS indices, which confirmed the absence of heat stress. As there was no incidence of heat stress, the environment was evaluated with respect to thermal comfort, in the measurements in which the PMV index was applicable and the PET index was calculated. Through the calculation of the PMV index, it was verified that in only one measurement the environment can be considered comfortable, in the others the environment is considered to be thermally uncomfortable. Through the calculation of the PMV index, it was verified that in only one measurement the environment can be considered comfortable, in the others the environment is considered to be thermally uncomfortable. The results of the PET index show that thermal discomfort was also characterized in most of the measurements.

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