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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.
11

Estudo do efeito de pausas introduzidas em testes de fadiga de amplitude variável. / Study of the effect of introduced pauses in fatigue tests under variable amplitude.

Clayton Mamedes Angelo 28 January 2016 (has links)
É muito importante para a indústria fornecer produtos competitivos e que exerçam corretamente as suas funções perante o cliente. Uma das ferramentas existentes para atingir estes objetivos é a realização de testes de fadiga e durabilidade cada vez mais refinados e em espaço mais curto de tempo. Uma das maneiras de se executar testes de fadiga mais precisos é utilizando parâmetros que sejam fiéis à solicitação que o produto sofre durante o seu uso. Com esse intuito surgiram os testes de fadiga sob amplitude variável. Juntamente com eles surgem as particularidades deste tipo de solicitação, que é de natureza complexa. Algumas particularidades são a dependência do resultado na história de carregamento (também chamada de \"interação de cargas\") e a variação abrupta do nível de carga durante o tempo de aplicação. Fenômenos estes chamados de sobrecarga ou subcarga (overload e underload), que aqui serão agrupados, muitas vezes de forma simplista, de perturbações no espectro de fadiga. A finalidade principal deste trabalho é descrever a influência das perturbações ocorridas nas solicitações nos testes de fadiga em regime de amplitude variável, mais precisamente em testes de bancada, em que se busca a reprodução de situações de trabalho reais de um componente. Apesar de esse assunto ser alvo de diversas investigações recentes, nenhum trabalho tem como foco a influência das paradas (completa remoção de carga) realizadas durante um teste de fadiga acelerado. Essas paradas são extremamente comuns na prática laboratorial, seja por manutenção do equipamento, inspeção da amostra ou necessidade de operação. O objeto alvo de estudo nesta pesquisa é um suporte metálico de buzina, utilizado em automóveis de passeio. Apesar de sua concepção simples, tal componente é responsável por exercer funções importantes e é sujeito a uma interessante gama de solicitações. Como resultado observou-se que a aplicação das paradas durante os testes de fadiga simulados no componente automotivo, provoca variações em sua vida útil total. E o tempo de parada também exerce influência nesta variação observada. Essas paradas não se encaixam perfeitamente nas classificações de perturbações no espectro registradas na literatura. Por esse motivo o trabalho se propõe ainda a sintetizar e uniformizar a terminologia para as variações abruptas de tensão aplicadas no tempo (as sobrecargas e as subcargas), tendo em vista que ocorre a falta de consenso entre os termos utilizados atualmente na literatura e seus respectivos conceitos. / It is very important to the industry to deliver competitive products that can properly perform their functions to the final customer. One existing tool for achieve this objective is the usage of abbreviated durability and fatigue tests. For more precise tests, the required parameters must be reliable when compared to the efforts that the component is submitted at the field during your real performance. In order to achieve these results, the fatigue tests under variable amplitude loading came to existence. Together came also in existence the singularities from this complex behavior. Some of these singularities are the dependence in loading history (also called \"load interaction effects\") and the abrupt load variation level during the test time. These phenomenons are called overloads or underloads. These particularities will be grouped in this work as \"perturbations\" on the fatigue spectrum. The main objective of this work is to describe the influence of these perturbations upon the fatigue tests under variable amplitude loading, more precisely on bench tests, where one seeks the concise reproduction of the real work situations for one component or system. Although this subject lately has caused more interest to the researchers, no work which focuses on the influence of the \"pauses\" (complete absence of load during the test) upon accelerated fatigue tests has been published yet until this moment. These pauses are extremely common due to equipment maintenance, test sample inspections or operational routines. The target of this work is a metallic horn bracket, which is used in light passenger vehicles. Although this is a simple component, it has important functions to perform and is subjected to a wide range of loads types. As result, there was been verified that the presence of the \"pause\" during the simulated fatigue tests causes changes in their total useful life. And the magnitude of the pause has your role too. Moreover, the pause do not properly fits into the current classifications for the perturbations on the fatigue specter that are today available on the literature. For theses reason, this work tries to resume and unify the terminology of the abrupt load variations during time (overloads and underloads) because there is some lack of consensus between the actual terminology and their concepts.
12

Produção, comércio e acumulação de riqueza em um município escravista mineiro: Lavras/MG (1870-1888) / Production, trade and accumulation of wealth in a municipality slave: Lavras/MG (1870 - 1888)

Vieira, Eduardo José 19 March 2015 (has links)
Esta pesquisa busca analisar a população e a riqueza do município de Lavras/MG, nos anos finais do regime escravista brasileiro, observando a estrutura da riqueza acumulada e as principais atividades produtivas da localidade. Tratou-se da riqueza da população total e, em especial, da elite local, sendo considerado como tal os processos que somaram mais de trinta contos de reis ou que possuíam mais de vinte cativos. Foram utilizados como fontes o Recenseamento Geral do Império de 1872 e os inventários post-morten disponíveis para o período. A partir dos dados do censo, buscou-se caracterizar a população lavrense acerca de indicadores como condição social, sexo, idade, condição conjugal e ocupação. De forma complementar, foram utilizados os dados dos inventários para caracterizar a população cativa de acordo com os diferentes tamanhos de escravarias. Os inventários foram utilizados também para identificar a estrutura da riqueza acumulada no município. Considerando os ativos divididos entre bens móveis, animais, escravos, imóveis rurais, imóveis urbanos, culturas e mantimentos, dívidas ativas, passivas e dinheiro e ações, foi possível identificar as principais opções de investimento da população local, considerando as diferentes faixas de riqueza e com especial atenção à riqueza da elite. Com os recursos apresentados foi possível concluir quanto à característica predominantemente rural e escravista do município, demonstrada tanto nos dados referentes à ocupação da população quanto na riqueza apresentada nos inventários, onde predomina a propriedade rural e o trabalho cativo. As principais atividades produtivas verificadas foram a criação de animais, o cultivo de alimentos como milho, arroz, feijão, e a produção de cana de açúcar, destinada à fabricação de açúcar e aguardente. As atividades comerciais se mostraram de grande importância no município, sendo que os maiores proprietários de riqueza eram, com frequência ao mesmo tempo, fazendeiros e comerciantes. Os altos valores aplicados em dívidas ativas também atestam a importância das atividades comerciais no município. Espera-se conseguir demonstrar, portanto, a importância das atividades de produção agropecuária e comércio na economia do município de Lavras e, em especial, no processo de acumulação de riqueza da elite lavrense. / This research seeks to analyze the Lavras / MG wealth, in the Brazilian slave final years, noting the structure of accumulated wealth and the main productive activities of the locality. It was focused the total population wealth and in particular the local elite, being considered as such processes which totaled more than thirty thousand reis or who had more than twenty captives. The Empire Census of 1872 and inventories postmortem available for the period were used as sources. From census data, we sought to characterize the Lavras population about indicators such as social status, gender, age, marital status and occupation. As a complement, the inventory data were used to characterize the captive population according to the different sizes of slave owners. The inventories were also used to identify the structure of the accumulated wealth in town. Considering the assets divided between movable, animals, slaves, rural properties, urban properties, crops and supplies, active debts, payables and cash and stock, it was possible to identify the main investment options of the local population, considering the different wealth groups and with special attention to the elite wealth. With the sources presented it was possible to conclude the predominantly rural and slave character of the city, demonstrated through the data regarding the occupation of the population and in wealth presented in inventories, dominated by rural property and bonded labor. The main productive activities verified were breeding, growing food such as corn, rice, beans, and the production of sugar cane, for the manufacture of sugar and brandy. Commercial activities showed great importance in the city, where the greatest wealth owners were often at the same time, farmers and traders. The high values applied to outstanding debt also attest to the importance of trade in the city. It is expected to demonstrate, therefore, the importance of agricultural production and trade activities in the economy of Lavras and in particular in the wealth accumulation process of Lavras elite.
13

The research of investment strategy analysis in Taiwan stock market-¡XThe comparison of value investment and growth investment

Yang, Ching-haur 02 August 2007 (has links)
The Value investment and Growth investment are investment strategies of choosing stocks. These two methods are adopted by international financial investment institutions and mutual fund managers. The study is aim to learn when we classify value stock and growth stock by market-to-book ratio and price-earning ratio, if the investment return would be higher than TSEC weighted index. In addition, we seek for a better investment strategy to improve investment performance further. The study also looks into market abnormal effects , such as January effect, size effect¡Ketc, and also discuss about the variables of stocks holding period and debt ratio. The monthly and yearly investment return rates are used to calculate 1, 2, 3, 4, and 5 year accumulated abnormal stock return ratio and evaluate if these variables affect investment performance of value stock and growth stock. The results are as following: 1. When classification of market-to-book ratio are adopted, the investment return of value stock is higher than growth stock. 2. When classification of market-to-book ratio are adopted, the investment return of low debt ratio stock is higher than high debt ratio stock. However, when classification of price-earning ratio are adopted, it is not obvious. 3. When bull market is formed in Taiwan stock market whose index is still low, invest in value stock could get a good long term investment performance. 4. Regarding the evaluation of risk, the vibration of growth stock is more than value stock. The vibration of TSEC weighted index is the least. 5. The January effect exists in Taiwan stock market. However, the size effect is not obvious. 6. TSEC weighted index and the Dow Jones Industrial index affect the investment return of value stock and growth stock; the TSEC weighted index, value stock and growth stock are positively correlated. The Dow Jones Industrial Index, value stock and growth stock are negatively correlated.
14

Efeitos da radiação em transistores túnel-FET de porta tripla. / Radiation effects on triple-gate tunnel-FET transistors.

Henrique Lanza Faria Torres 28 May 2018 (has links)
Frente à crescente necessidade de que novas tecnologias sejam capazes de operar com confiabilidade em ambientes hostis, a análise dos efeitos da radiação ionizante em dispositivos semicondutores se tornou um ramo de pesquisa em contínua ascensão, contribuindo para o desenvolvimento de tecnologias estratégicas e promovendo o aprimoramento científico e o desenvolvimento tecnológico da humanidade. Por outro lado, a atual tecnologia CMOS de fabricação de circuitos integrados apresenta sinais de limitação, em grande parte, devido às características físicas inerentes ao seu princípio de funcionamento, sendo necessário, portanto, que dispositivos com novos mecanismos de operação e geometrias sejam desenvolvidos. Dentre eles, transistores de tunelamento induzido por efeito de campo (TFET) se destacam por apresentarem menor corrente de dreno quando desligados e a possibilidade de se atingir inclinações de sublimiar abaixo do limite teórico estabelecido por dispositivos MOSFET de 60 mV/déc à temperatura ambiente, permitindo-se a redução da tensão de alimentação dos transistores para cerca de 0,5 V. Buscando contribuir com as necessidades destas duas áreas de pesquisa, neste projeto de mestrado, foi analisado o comportamento de TFETs de silício com porta tripla, fabricados sobre lâmina SOI (silício sobre isolante), submetidos a até 10 Mrad(Si) de dose acumulada total enquanto não polarizados, gerada por uma fonte de prótons de 600 keV de energia. Em uma análise inicial, após exposição de dispositivos de 1 µm de largura de aleta a uma dose de 1 Mrad(Si), foi possível observar uma redução no nível corrente de dreno de estado ligado do dispositivo (ION ? 300 pA) de até 10%, não associada à uma alteração da corrente de porta. Além disso, o efeito da radiação nesses transistores reduz de 10% para 2% quando se aumenta o comprimento do canal de 150 nm para 1 µm. As razões para ambos os fenômenos foram discutidas com base na competição entre os efeitos de divisão da corrente de dreno na primeira e segunda interfaces e do aumento da resistência de canal em dispositivos mais longos. Para uma análise em função da dose acumulada total, dispositivos SOI TFET e SOI MOSFET, ambos de porta tripla, foram caracterizados eletricamente 14 dias após cada etapa de irradiação. De maneira geral, dispositivos de ambas as tecnologias, com largura de aleta igual a 40 nm, apresentaram baixa susceptibilidade aos efeitos cumulativos da radiação ionizante. No entanto, quando considerados dispositivos com largura de aleta muito maior que a altura da aleta (WFIN = 1 µm), nos quais a influência das portas laterais sobre o acoplamento eletrostático do canal é praticamente inexistente, transistores túnel-FET se destacaram positivamente. Esses dispositivos se mostraram resistentes aos efeitos de dose ionizante total (TID) mesmo para doses de 5 Mrad(Si), enquanto os transistores SOI MOSFET apresentaram uma variação gradual de seus parâmetros a cada dose acumulada. Um exemplo disso é a variação observada na inclinação de sublimiar, de 32,5% nos transistores SOI MOSFET e 5,6% nos transistores SOI TFET. Somente após 10 Mrad(Si) de irradiação por prótons é que os TFETs de aleta larga apresentaram variações mais significativas em sua curva de transferência (ID x VG). Tanto para a configuração como tipo P quanto para a configuração como tipo N, notou-se um deslocamento de até 80 mV da curva de transferência do dispositivo para a esquerda, provocado, segundo análise via simulações, pelas cargas fixas positivas geradas pela irradiação no óxido enterrado do dispositivo. Adicionalmente, foi possível observar um aumento da corrente de tunelamento assistido por armadilhas (TAT) nesses dispositivos, provocada pelo aumento da densidade de estados de interface causada também pelos efeitos de TID. O aumento de TAT foi reconhecido como o principal responsável pela degradação de 23,3% da inclinação de sublimiar dos TFETs, com WFIN igual 1 µm, após 10 Mrad(Si). Apesar das mudanças observadas, foi possível se sugerir, através da comparação com transistores SOI MOSFET de dimensões equivalentes, que transistores de tunelamento induzido por efeito de campo podem, futuramente, se tornar referência no quesito imunidade aos efeitos de dose ionizante total. / In light of the increasing need for new technologies to be able to operate reliably in harsh environments, the analysis of the effects of ionizing radiation on semiconductor devices has become a continually rising field of research, contributing to the development of strategic technologies and promoting scientific improvement and technological development of humankind. On the other hand, the current CMOS technology for the manufacture of integrated circuits shows signs of limitation, mostly, due to the physical characteristics inherent to its operating principle, thus, it is necessary that devices with new operating mechanisms and geometries be developed. Among them, tunnel field-effect transistors (TFET) stand out because of its lower OFF state current and the possibility of reaching subthreshold swing below the theoretical limit established by MOSFET devices of 60 mV/dec at room temperature, allowing to reduce transistors supply voltage to about 0.5 V. In order to contribute with both areas, the behavior of silicon based triple gate TFETs fabricated on a SOI (silicon-on-insulator) substrate and exposed to a total cumulative dose of 10 Mrad (Si) (while not biased) generated by a 600 keV proton beam was analyzed. In an initial analysis after exposure of 1 µm width devices to 1 Mrad(Si), it was possible to observe an ON state current reduction (ION ? 300 pA) up to 10%, not associated to a gate current change. Beyond that, irradiation effects on these devices reduce from 10% to 2% with the channel length increasing from 150 nm to 1 µm. The reasons behind these phenomena were discussed based on the competition between a high channel resistance present in longer devices and the TFET drain current reduction due to the irradiation. For a total cumulative dose analysis, triple gate SOI TFET and triple gate SOI MOSFET devices were characterized 14 days after each irradiation phase. In general, devices of both technologies, with 40 nm fin width, presented low susceptibility to the cumulative effects of ionizing radiation. However, for devices with fin width larger than fin height (WFIN = 1 µm) in which the influence of side gates on the electrostatic coupling of the channel is weak, tunnel-FET transistors have stood out. These devices were resistant to the effects of total ionizing dose (TID) even for doses as high as 5 Mrad(Si), while SOI MOSFET transistors showed a gradual variation of their parameters at each accumulated dose. The variation observed for the subthreshold swing, for example, was about 32.5% for SOI MOSFET devices and 5.6% for SOI TFET devices. TFETs with wider fin have shown significant variations on its transfer characteristic (ID x VG) only after 10 Mrad(Si) of proton irradiation. For both P-type and N-type configurations, it was observed a shift of the transfer curve to the left up to 80 mV caused by, according to simulations, the positive fixed charges generated in the buried oxide by irradiation. In addition, it was possible to observe a trap assisted tunneling (TAT) current increase caused by interface states promoted by TID effects. The increase of TAT was recognized as the main responsible for the degradation of 23.3% of the subthreshold swing of the TFETs after 10 Mrad(Si). In spite of the observed changes, it was possible to suggest, through comparison with SOI MOSFET devices of equivalent dimensions, which tunnel field-effect transistors may become a reference when considering immunity against total ionizing dose effects.
15

Nova abordagem para a interpretação da Reserva Legal com auxílio da geoestatística. / New approach to the interpretation of the Legal Reserve with the aid of geostatistics.

Miriam Harumi Okumura 17 February 2014 (has links)
A Floresta Amazônica é palco de um grande número de atividades de desflorestamento, como a mineração artesanal, agropecuária e comércio de madeira. A fim de se ter uma diminuição dos impactos ambientais, os órgãos fiscalizadores têm tentado regular estas atividades e orientá-las para métodos de operação mais responsável. Este trabalho descreve a iniciativa por meio do monitoramento dessas áreas de floresta localizadas perto dessas regiões de desmatamento, porque os elementos fundamentais, tais como a biomassa e acúmulo de carbono das árvores podem ser adequadamente monitorados contra distúrbios ocasionais trazidos por essas atividades. A atual abordagem padrão na Amazônia é monitorar todas as árvores da floresta dentro de uma área chamada de transecto, também designado como inventário florestal, mantendo um registro rigoroso de seu comportamento e crescimento. No entanto, essas atividades são restritas às áreas de controle que estão localizados em regiões estratégicas e não representam toda a área a ser monitorada. Esta pesquisa explora uma nova metodologia baseada na geoestatística e destinada a otimização da amostragem, estendendo-se para o estudo de áreas florestais muito maiores, mantendo a utilização dos recursos humanos unitária inalterada, e, ao mesmo tempo, aumentar a superfície das áreas de estudo e a manter a confiança nos resultados. A metodologia proposta permite a seleção da Reserva Legal - RL, a ser feita de acordo com a distribuição real de acumulação de carbono da floresta, em vez de confiar na utilização de área percentual proposta por lei e no senso comum de proprietários / órgãos fiscalizadores. Esta metodologia foi aplicada na Floresta Nacional de Tapajós (FLONA Tapajós), no Estado do Pará, Brasil, utilizou-se de conjunto de dados disponíveis, para otimizar as amostras e monitorar a capacidade da floresta de armazenar carbono. A presente metodologia pretende contribuir para uma diminuição do custo das atividades de monitoramento por unidade de área, aumento da precisão para localização RL, e simplificação dos procedimentos através da aplicação de um conjunto de ferramentas de fácil utilização. Os resultados mostraram que a aplicação de estudos geoestatísticos para determinação de RL é um procedimento viável, pois a estrutura do variograma se mantém mesmo com a amostragem sofrendo uma diminuição randômica de até 50% da área de cobertura vegetal, conseguindo manter o mesmo resultado da amostragem na totalidade da cobertura vegetal. / The Amazon Rainforest is the scene of a large number of deforestation activities such as artisanal mining, agriculture and timber trade. For the purpose of have reduced environmental impacts, regulatory agencies have attempted to regulate these activities and direct them towards more responsible methods of operation. This paper describes the initiative by monitoring these forest areas located near these regions of deforestation, because the core elements, such as biomass and carbon accumulation of the trees can be adequately monitored against occasional disturbances brought by these activities. The current standard approach in the Amazon is to monitor all the trees of the forest within an area called the transect, also designated as forest inventory, keeping a strict record of their behavior and growth. However, these activities are restricted to control areas that are located in strategic regions and do not represent the whole area to be monitored. This research explores a new methodology based on geostatistics and designed to optimize the sampling, extending the study of much larger forest areas, keeping unchanged the use of human resources unit, and at the same time increase the surface areas of study and to maintain confidence in the results. The proposed methodology allows the selection of the Legal Reserve - RL, to be made according to the actual distribution of carbon accumulation in the forest, instead relying in using area percentage proposed by law and common sense of proprietary / regulatory agencies. This methodology was applied in the Tapajós National Forest (FLONA Tapajós), State of Pará, Brazil, we used the data set available, to optimize the sample and monitor the forest\'s ability to store carbon. This methodology intends to contribute to reducing the cost of monitoring activities per unit area, increased precision for location RL, and simplifying procedures by applying a set of easy to use tools. The results showed that application of geostatistical studies for determination of RL is a viable procedure, because the structure of the variogram is maintained even with a random sampling suffering decreased to 50% of the area of vegetation, even managing to keep the sampling result the total vegetation cover.
16

Efeito da ingestão de cafeina sobre o deficit acumulado de oxigenio, sinal eletromiografico dos musculos superficiais do quadriceps e desempenho fisico de ciclistas / Effect of the caffeine ingestion on the maximum accumulated deficit of oxygen, electromyographic signs of the superficial quadrideps muscles and performance in cyclists

Altimari, Leandro Ricardo 31 July 2008 (has links)
Orientador: Antonio Carlos de Moraes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação Fisica / Made available in DSpace on 2018-08-11T14:01:30Z (GMT). No. of bitstreams: 1 Altimari_LeandroRicardo_D.pdf: 2753845 bytes, checksum: 72487f2f03add9833dd0a2e582f711e2 (MD5) Previous issue date: 2008 / Resumo: O propósito do presente estudo foi investigar o efeitos da ingestão de cafeína (6 mg.kg-1) sobre o desempenho físico e mecanismos associados à fadiga de ciclistas em esforços supramáximos. Fizeram parte do estudo dez ciclistas com idade média de 27,5 ± 4,1 anos e tempo médio de prática na modalidade de 9,8 ± 4,7 anos. Os indivíduos foram submetidos a diferentes situações experimentais: 1) Determinação do consumo de oxigênio de pico (VO2pico) e limiar ventilatório (LV2); 2) Determinação da demanda acumulada de oxigênio (DEO2) (4 sessões de exercício submáximo - 60, 70, 80 e 90% do VO2pico), e 3) Teste retangular supramáximo (110% do VO2pico) para determinação do MAOD realizado em duas situações distintas (CAF - cafeína e PL - placebo/maltodextrina) aleatoriamente, em sistema duplo cego, com no mínimo 72 horas de intervalo entre os testes. Os sujeitos foram submetidos a mensuração de parâmetros antropométricos e anamnese nutricional para determinação do habito alimentar. Os sinais EMG foram coletados durante o teste retangular supramáximo (MAOD). O esforço percebido utilizando a escala de 6-20 pontos de Borg (1982) foi reportado a cada 30s de exercício no teste retangular supramáximo (MAOD). A concentração de lactato sangüíneo foi analisada em repouso (-60 min), imediatamente antes (0 min) e após (1, 3, 5, 7 e 10 min) o teste de MAOD nas condições CAF e PL. Os resultados demonstraram que o tempo de exaustão, a DEAO2 e o MAOD foram significantemente maiores na condição CAF comparada a PL (P<0,05). Não foram constatadas diferenças significantes na atividade EMG (RMS) dos músculos VL, VM, RF e QF integrados entre as condições CAF e PL em todos os períodos de tempo analisados (P>0,05). Quando comparado os slopes de FM dos músculos VL, VM, RF e QF integrados entre as condições CAF e PL estes se mostraram significantemente menores para ambos os músculos na condição CAF (P<0,05). O slope da PSE foi significantemente maior na condição CAF comparado a PL (P<0,05). Entretanto, o y-intercepto apresentou valor significantemente menor na condição CAF comparado a PL (P<0,05). Vale ressaltar que o valor de PSE inicial (30 s) medido durante o teste de MAOD na condição CAF foi significantemente menor comparado a PL (P <0,05). Não foram constatadas diferenças significantes nas concentrações de lactato sanguíneo entre as condições CAF e PL (P>0,05). Podemos concluir que a ingestão de cafeína (6 mg.kg-1) melhorou o desempenho anaeróbio pela atenuação da taxa de fadiga muscular causada por provável aumento na velocidade da condução dos impulsos nervosos para as fibras musculares / Abstract: The purpose of this study was to investigate the effects of the caffeine ingestion (6 mg.kg-1) on performance and mechanisms associated with the fatigue of cyclists in efforts supramaximum. Ten cyclists (age 27.5 ± 4.1 years; cycling experience 9.8 ± 4.7 years) were submitted to different experimental situations: 1) determination of the peak oxygen consumption (VO2pico) and ventilatory threshold (LV); 2) Determination of the accumulated oxygen demand (DEO2) (4 sessions of submaximum exercise - 60, 70, 80 and 90% of VO2pico), and 3) Supramaximum constant load test (110% of VO2pico) for determination of MAOD accomplished randomized in two different situations (CAF - caffeine and PL - placebo/maltodextrine), in double blind way, with an interval among tests with at least 72 hours. The subjects were submitted to anthropometric measurement and nutritional anamnesis for determination of the eating habits. The EMG signs were collected during the supramaximum constant load test (MAOD). The ratings of perceived exertion (PSE) were acquired using the 6-20 Borg scale (1982) being reported at each 30s of exercise during MAOD test. The blood lactate was analyzed in rest (-60 min), immediately before (0 min) and after (1, 3, 5, 7 and 10 min) during the MAOD test at CAF and PL conditions. The results demonstrated that the time of exhaustion, DEAO2 and MAOD were significantly larger in CAF than in PL condition (P < 0.05). Significant differences were not verified in the EMG activity (RMS) from Vastus Lateralis (VL), Vastus Medialis (VM), Rectus Femoris (RF) and integrated Quadriceps Femoris (QF) muscles among CAF and PL conditions during all of the analyzed periods (P > 0.05). When compared the mean power frequency (MPF) slopes of the muscles VL, VM, RF and QF integrated among the conditions CAF and PL these smaller significantly were shown for both muscles in the condition CAF (P < 0.05). The PSE slope was significantly higher during CAF when compare to PL condition (P < 0.05). However, the y-intercept presented significantly smaller value in CAF than in PL condition (P < 0.05). It is worthwhile to highlight that the initial value of PSE (30 s) measured during the MAOD test during CAF condition was significantly smaller than PL (P < 0.05). No significant differences were verified in the blood lactate concentrations between CAF and PL conditions (P > 0.05). It is possible to conclude that caffeine ingestion (6 mg.kg-1) improved anaerobic performance with the reduction of the rate of muscle fatigue, which could be explained by an increase in the firing rate of the neural impulse to muscles fibers / Doutorado / Ciencias do Desporto / Doutor em Educação Física
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Produção, comércio e acumulação de riqueza em um município escravista mineiro: Lavras/MG (1870-1888) / Production, trade and accumulation of wealth in a municipality slave: Lavras/MG (1870 - 1888)

Eduardo José Vieira 19 March 2015 (has links)
Esta pesquisa busca analisar a população e a riqueza do município de Lavras/MG, nos anos finais do regime escravista brasileiro, observando a estrutura da riqueza acumulada e as principais atividades produtivas da localidade. Tratou-se da riqueza da população total e, em especial, da elite local, sendo considerado como tal os processos que somaram mais de trinta contos de reis ou que possuíam mais de vinte cativos. Foram utilizados como fontes o Recenseamento Geral do Império de 1872 e os inventários post-morten disponíveis para o período. A partir dos dados do censo, buscou-se caracterizar a população lavrense acerca de indicadores como condição social, sexo, idade, condição conjugal e ocupação. De forma complementar, foram utilizados os dados dos inventários para caracterizar a população cativa de acordo com os diferentes tamanhos de escravarias. Os inventários foram utilizados também para identificar a estrutura da riqueza acumulada no município. Considerando os ativos divididos entre bens móveis, animais, escravos, imóveis rurais, imóveis urbanos, culturas e mantimentos, dívidas ativas, passivas e dinheiro e ações, foi possível identificar as principais opções de investimento da população local, considerando as diferentes faixas de riqueza e com especial atenção à riqueza da elite. Com os recursos apresentados foi possível concluir quanto à característica predominantemente rural e escravista do município, demonstrada tanto nos dados referentes à ocupação da população quanto na riqueza apresentada nos inventários, onde predomina a propriedade rural e o trabalho cativo. As principais atividades produtivas verificadas foram a criação de animais, o cultivo de alimentos como milho, arroz, feijão, e a produção de cana de açúcar, destinada à fabricação de açúcar e aguardente. As atividades comerciais se mostraram de grande importância no município, sendo que os maiores proprietários de riqueza eram, com frequência ao mesmo tempo, fazendeiros e comerciantes. Os altos valores aplicados em dívidas ativas também atestam a importância das atividades comerciais no município. Espera-se conseguir demonstrar, portanto, a importância das atividades de produção agropecuária e comércio na economia do município de Lavras e, em especial, no processo de acumulação de riqueza da elite lavrense. / This research seeks to analyze the Lavras / MG wealth, in the Brazilian slave final years, noting the structure of accumulated wealth and the main productive activities of the locality. It was focused the total population wealth and in particular the local elite, being considered as such processes which totaled more than thirty thousand reis or who had more than twenty captives. The Empire Census of 1872 and inventories postmortem available for the period were used as sources. From census data, we sought to characterize the Lavras population about indicators such as social status, gender, age, marital status and occupation. As a complement, the inventory data were used to characterize the captive population according to the different sizes of slave owners. The inventories were also used to identify the structure of the accumulated wealth in town. Considering the assets divided between movable, animals, slaves, rural properties, urban properties, crops and supplies, active debts, payables and cash and stock, it was possible to identify the main investment options of the local population, considering the different wealth groups and with special attention to the elite wealth. With the sources presented it was possible to conclude the predominantly rural and slave character of the city, demonstrated through the data regarding the occupation of the population and in wealth presented in inventories, dominated by rural property and bonded labor. The main productive activities verified were breeding, growing food such as corn, rice, beans, and the production of sugar cane, for the manufacture of sugar and brandy. Commercial activities showed great importance in the city, where the greatest wealth owners were often at the same time, farmers and traders. The high values applied to outstanding debt also attest to the importance of trade in the city. It is expected to demonstrate, therefore, the importance of agricultural production and trade activities in the economy of Lavras and in particular in the wealth accumulation process of Lavras elite.
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Optimal retirement savings : a South African perspective

Louw, Elbie January 2015 (has links)
is worldwide concern that people do not save enough towards retirement. To stimulate savings, tax incentives are a method employed by governments to encourage retirement savings. In this context, the asset allocation decisions that individuals make and the asset allocation restrictions that are imposed by regulators in an attempt to protect retirement savings, potentially impact the retirement ending wealth, which could be accumulated in the pre-retirement phase of an individual. The objective of the study was to determine the impact of tax legislation, Regulation 28 of the Pension Funds Act (24/1956) and asset allocation choices on accumulated retirement ending wealth and what could be deemed appropriate for most individuals considering different time horizons. Therefore, the aim of this study was two-fold: to determine whether pension fund legislation which limits the exposure to risky asset classes resulted in sub-optimal accumulated retirement ending wealth despite the associated tax savings; and to determine whether life cycle retirement funds, as opposed to different balanced retirement funds, were appropriate for most individuals. The study did not find support for the notion that direct investment funds dominated high equity balanced retirement funds that complied with Regulation 28 as measured by firstorder and almost stochastic dominance. Despite the higher asset allocation to equities that was possible with direct investments, this benefit was outweighed by the tax savings attributable to retirement funds. Additionally, the results of the study refuted the notion that a direct investment fund could be optimal over a long investment horizon. The implication of the finding was that an individual saving for retirement should, firstly, do so by taking full advantage of the tax savings that retirement funds offered. Hence retirement funds are an effective retirement saving tool despite the limitations on high-risk asset class allocations. The study found only limited support for the hypothesis that a theoretical retirement fund with a 100 per cent allocation to equities dominated a high equity balanced retirement fund that complied with Regulation 28 (particularly in the case of a 100 per cent local equity retirement fund compared with a Regulation 28 high equity balanced fund with no foreign equity exposure). Because the South African equity asset class was very volatile (annualised standard deviation of 19.8 per cent against 17.4 per cent for local against foreign equity in the data used in the study), a high exposure could lead to very low accumulated retirement ending wealth values; the intent of Regulation 28 was to protect the retirement savings of individuals against such adversity. Despite being perceived as very restrictive on the individual, the findings could not conclude that Regulation 28 restrictions on asset classes were inappropriate. This study provided no support for the notion that a life cycle fund dominated a balanced fund with similar starting asset allocation from the perspective of accumulated retirement ending wealth. This raised the question whether life cycle funds, which are often included as default options for members of retirement funds, have a place. Hence they were likely not the optimal choice compared with a balanced fund counterpart with similar starting asset allocation. However, they could be attuned to the preferences of the individual (such as risk and personal preferences) rather than a rational objective assessment of one fund compared with another. The study provided mixed support for whether a life cycle fund dominated a balanced fund with dissimilar starting asset allocations. This indicated that whether there was a place for a life cycle fund in any retirement fund default options, or whether it was optimal compared with an alternative balanced fund, strongly depended on the underlying asset allocations of the funds while the length of the glide path, the investment horizon as well as the risk and return characteristics of the investable universe could also influence the conclusion. The study uniquely contributed to the retirement savings question with evidence that did not support the notion that Regulation 28 of the Pension Funds Act was necessarily inappropriate to serve the purpose of protecting retirement savings. The study also showed how the lower risk attribute of life cycle strategies impacted on accumulated retirement ending wealth, how it compared with balanced funds and which choice would be appropriate for most individuals. Because the life cycle industry is a fast-growing portion of the retirement fund market and becoming more popular as default options in retirement funds, the study contributed by contrasting life cycle funds with balanced funds and showed that the choice of which fund was optimal, was driven by the different characteristics of the funds such as investment horizon, starting and ending asset allocations as well as the length of the glide path. / Thesis (PhD)--University of Pretoria, 2015. / tm2016 / Financial Management / PhD / Unrestricted
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The applicability of accumulated degree-day calculations on enclosed remains in a lotic aquatic environment

Stark, Sally C. 09 November 2019 (has links)
This study examined the differences in decomposition rates and the resulting postmortem submergence interval (PMSI) of stillborn pigs and decapitated adult pig heads enclosed in plastic trash bags. Sixteen neonate pigs were divided into two variable categories: exposed and submerged in water, enclosed in a plastic trash bag and submerged in water. Upon recovery, each sample was assigned a Total Body Score. Eighteen decapitated adult pig heads were divided into two variable categories: nine heads were enclosed in plastic trash bags, and nine heads left exposed in the water. Twelve decapitated pig heads were divided into two terrestrial variable categories: six heads were enclosed in plastic trash bags and allowed to decompose on land, and six heads were left exposed on land. Accumulated degree-days (ADD) were calculated following the scoring guides provided in Moffatt et al. (2016), Megyesi et al. (2005) and Heaton et al. (2010). These guides were used to create a baseline decomposition rate established from the control groups decay rate. This baseline in the decomposition rate was then used to establish a measurable difference between exposed and enclosed samples. It was hypothesized that head samples submerged (enclosed/exposed) would decompose slower than the terrestrial samples (enclosed/exposed). It was further hypothesized that all enclosed/submerged samples would decompose slower than the exposed/terrestrial remains. A univariate analysis of variance (ANOVA) test found no statistically significant interactions between submerged, enclosed or exposed remains, indicating that the enclosure of remains in a plastic trash bag, and subsequent submergence or not did not affect the decomposition rate of either sample. An additional ANOVA found statistically significant differences between the rate of neonate sample decomposition and adult head sample decomposition. Paired sample t-tests produced statistically significant results that indicate the inaccuracy of the ADD calculation methods developed by Megyesi et al. (2005) and Heaton et al. (2010) to neonate-sized remains, decapitated heads, submerged enclosed/exposed samples or terrestrial enclosed/exposed samples.
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The Effects of Coarse Aggregate Cleanliness on Asphalt Concrete Compactability and Moisture Susceptibility

Williams, Kevin Lamar 11 August 2012 (has links)
Twelve field projects were studied where fortyour locations were evaluated to assess the cause or causes of asphalt concrete that exhibits ‘tender zone’ characteristics and to investigate the tendency of these mixes to be susceptible to moisture damage. Data was collected during construction and samples were obtained to conduct laboratory tests. Field and laboratory data was used to develop multiple regression equations to predict final in place air voids and moisture susceptibility. The overall conclusion was that compactability appeared to be predicted in a reasonable manner while moisture susceptibility did not. The Methylene Blue test appears promising when used in conjunction with cold feed and/or mix moisture as a means of providing guidance for achieving higher in place density. The tensile strength ratio (TSR) test as performed in this research on laboratory compacted specimens was found to be questionable in terms of its ability to predict field moisture susceptibility.

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