Early antebellum defenders of slavery acknowledged that slavery created problems for southern society. They contended, however, that slave society was better and more natural than other forms of social organization. Thomas R. Dew, William Harper, and James Henry Hammond each expressed a social philosophy in which slavery had a crucial role in preserving social order. They argued from the basis of social organicism, the idea that society should have an elite that controlled the masses. For all three men, slavery represented a system of order that helped balance the dangers of democracy. Significantly, however, all three men recognized that the slave system was not perfect, and despite their defense of slavery, argued that it was a human institution and therefore corruptible.

Doctor of Philosophy / Department of History / Mark P. Parillo / The Distant Early Warning (DEW) Line, a key program under President Dwight D. Eisenhower’s “New Look” policy, prepared the United States defense posture for “the long haul” in the Cold War. Eisenhower wanted to prevent the escalation of military costs while still providing an adequate defense. Eisenhower emphasized a retaliatory capability and improved continental defenses, the so-called “sword and shield,” which are key features of the New Look. The DEW Line would prove to be a vital component of both. Whereas the initial emphasis of the DEW Line was to warn against attack providing for both active and passive defense measures, soon there was a definite “counter-offensive” role for the DEW Line as well—the protection of the primary retaliatory capability of the United States: the Strategic Air Command (SAC). The place of the DEW Line in the history of the Cold War has been an under appreciated topic. With the exception of the scholarship from the 1950s and early 1960s, only recently have continental defense and particularly the DEW Line been removed from the shadows of other Cold War events, strategies, and military programs. This doctoral thesis is an account of the DEW Line’s conception, implementation, and position in Eisenhower’s New Look and deterrent strategy. The DEW Line proved to be a cardinal feature of Eisenhower’s New Look strategy: it strengthened overall U.S. defenses and defense posture as the one element of U.S. defense policy (“New Look”) that improved and connected both the active and passive measures of continental defense by providing early warning against manned bombers flying over the polar region; it bolstered the deterrent value of SAC; and it was instrumental in developing closer peacetime military cooperation between the United States and Canada. In fact, U.S.- Canadian diplomacy during the 1950s offers an important case study in “superpowermiddle power” interaction. However, despite the asymmetry in their relationship, U.S.- Canadian defense policies proved to be analogous. All of these objectives could not have been accomplished without the technological and logistical abilities necessary to construct successfully the DEW Line.

Ce manuscrit présente une étude de la susceptibilité d’un amplificateur faible bruit (LNA)AsGa aux agressions électromagnétiques de forte puissance. La notion d’agressionélectromagnétique de forte puissance définit, du point de vue de la CEM, un environnementélectromagnétique particulier où les niveaux de champ électromagnétique sont tels qu’ilspeuvent engendrer une dégradation physique des composants électroniques du systèmevictime. Ces champs peuvent être générés par des systèmes particuliers appelés AED EM(arme à énergie dirigée électromagnétique).Cette étude s’intéresse ainsi non seulement à l’explication des effets physiques observés surles composants cibles, mais également à l’influence des paramètres de la sourceélectromagnétique sur la susceptibilité du composant.Cette thèse a été encadrée par les équipes du laboratoire IMS de l’université de Bordeauxd’une part, et du CEA Gramat d’autre part. / In this PhD thesis dissertation, a study of a GaAs low-noise amplifier (LNA) susceptibility tohigh power electromagnetic interference is presented.The term high power electromagnetic interference refers to a particular electromagneticenvironment in which E-field and H-field levels are high enough to cause physical damage tothe victim’s system electronic components.Such high level fields can be generated by dedicated systems, called electromagneticdirected energy weapons (DEW).The study presented in this document focuses not only on explaining failure mechanismstriggered by such interference, but also shows discussion on electromagnetic sourcesparameters trimming influence on component’s susceptibility.

A duração do período de molhamento (DPM) é de grande importância para a epidemiologia de doenças de plantas, pois desempenha papel fundamental em alguns processos epidemiológicos. Dessa forma, sua determinação torna-se indispensável para o entendimento da relação entre o clima e doenças de plantas. Sendo assim, este estudo teve como objetivos: definir uma posição padrão de instalação de sensores cilíndricos para a medida da DPM sobre gramado, avaliar a variabilidade espacial dessa variável em três diferentes culturas, relacionar a DPM medida em culturas agrícolas com aquela obtida em posto meteorológico e comparar a estimativa da DPM obtida com modelos empíricos com aquela medida com sensores eletrônicos. Na fase anterior à sua instalação no campo, todos os sensores eletrônicos foram previamente pintados com tinta látex e tratados termicamente. Após essa etapa, os sensores cilíndricos foram instalados sobre gramado a 30 cm de altura voltados para o sul. No período inicial, os sensores cilíndricos foram mantidos paralelos à horizontal, visando-se a avaliar a variabilidade entre os mesmos. Posteriormente, foram testados cinco diferentes ângulos de instalação. As medidas obtidas por esses sensores foram comparadas com a medida padrão, obtida por sensor de placa a 30 cm de altura e 45º de inclinação. Com a finalidade de se avaliar a variabilidade espacial da DPM, sensores eletrônicos de DPM foram distribuídos no dossel de três culturas: algodão, banana e café. As medidas obtidas nessas culturas foram comparadas com as fornecidas por sensor de placa em posição padrão. A estimativa da DPM foi feita por meio dos seguintes modelos: NHUR > 87%, CART, DPO e limiar estendido de umidade relativa para os períodos seco e chuvoso. As medidas obtidas por sensores cilíndricos sobre gramado apresentaram boa acurácia e precisão. A variação do ângulo de instalação não demonstrou ter efeito expressivo sobre a medida dos sensores cilíndricos para as condições locais. Contudo, é recomendável inclinar o sensor cilíndrico, uma vez que, trabalhos anteriores demonstram que esse pode superestimar a DPM quando instalado na horizontal. A avaliação da variabilidade espacial da DPM demonstrou que essa variável é influenciada pelas condições determinantes do microclima das culturas. O padrão de variação da DPM foi distinto para cada uma das culturas. Na cultura do algodão não foram observadas variações expressivas da DPM. Já no cafeeiro a DPM foi mais longa nas partes baixas da planta, enquanto que na cultura da banana essa foi mais longa no topo da cultura. Foram obtidas boas relações entre a DPM medida sobre gramado e aquela obtida no topo das culturas, demonstrando que é possível estimar tal variável por meio de dados obtidos em posto meteorológico. Os modelos NHUR > 87%, CART e DPO forneceram boas estimativas da DPM com erro absoluto médio variando de 1,4 a 2,8 h nos dois períodos avaliados. Durante a estação seca, os três primeiros modelos tenderam a subestimar a DPM. O modelo do limiar estendido de umidade relativa foi o que apresentou o pior desempenho entre os modelos avaliados, não sendo recomendável sua aplicação para condições semelhantes às deste estudo. / Leaf wetness duration (LWD) is a very important variable for plant disease epidemiology, since it plays an important role in some epidemiological processes. So its determination is essential for the understanding of the climate and plant disease relationship. Therefore, the objectives of this study were: to determine the standard deployment for cylindrical LWD sensors over turfgrass; to assess the spatial variability of this variable in three different crops; to relate the LWD measured at three different crop canopies to that obtained in a weather station; and to compare the LWD estimated by empirical model with that measured by electronic sensors. Before the field assessments, all electronic sensors were painted with white latex paint and submitted to a heat treatment. After this first stage, all cylindrical sensors where installed over turfgrass at 30-cm height deployed facing south. Firstly, all cylindrical sensors were deployed at horizontal in order to assess the variability among them. After that, five different deployment angles were tested. The measurements provided by those sensors were compared with the standard measurement, provided by flat plate sensors at 30-cm height and deployed at 45º. In order to assess the LWD spatial variability, electronic sensors were placed in three different crop canopies: cotton, banana and coffee. The measurements obtained in those crops were compared with LWD measured by flat plate sensors in a standard deployment over turfgrass. LWD were estimated using the following models: NHRH>87%, CART, DPD e extended threshold of relative humidity, for the dry and wet seasons. The measurements provided by cylindrical sensors over turfgrass had good accuracy and precision. The change in the angle of sensor deployment had no effect on LWD measured by cylindrical sensors, for the studied conditions. However, cylindrical sensors should not be deployed at horizontal because previous studies showed that they could overestimate LWD when deployed at horizontal. The LWD spatial variability assessment showed that this variable is dependent on the plant and/or crop conditions, which control the canopy microclimate. The pattern of variation of LWD was different for each crop assessed. In the cotton crop, LWD variations were negligible. On the other hand, in the coffee crop LWD was longer in the lower parts of the canopy while in the banana crop it was longer in the top of the canopy. A good correlation between LWD measured over turfgrass and that obtained in the crop top was achieved, which demonstrates that it is possible to estimate LWD using weather station data. The models NHRH>87%, CART, DPD provided good estimates of LWD with mean absolute error ranging from 1.4 to 2.8 h in both dry and wet periods. During the dry season, those models overestimated the LWD. The extended threshold model had the worst performance in relation to the other models, so it is not advised to use this model for similar climate conditions to this study.

A duração do período de molhamento (DPM) é de grande importância para a epidemiologia de doenças de plantas, pois desempenha papel fundamental em alguns processos epidemiológicos. Dessa forma, sua determinação torna-se indispensável para o entendimento da relação entre o clima e doenças de plantas. Sendo assim, este estudo teve como objetivos: definir uma posição padrão de instalação de sensores cilíndricos para a medida da DPM sobre gramado, avaliar a variabilidade espacial dessa variável em três diferentes culturas, relacionar a DPM medida em culturas agrícolas com aquela obtida em posto meteorológico e comparar a estimativa da DPM obtida com modelos empíricos com aquela medida com sensores eletrônicos. Na fase anterior à sua instalação no campo, todos os sensores eletrônicos foram previamente pintados com tinta látex e tratados termicamente. Após essa etapa, os sensores cilíndricos foram instalados sobre gramado a 30 cm de altura voltados para o sul. No período inicial, os sensores cilíndricos foram mantidos paralelos à horizontal, visando-se a avaliar a variabilidade entre os mesmos. Posteriormente, foram testados cinco diferentes ângulos de instalação. As medidas obtidas por esses sensores foram comparadas com a medida padrão, obtida por sensor de placa a 30 cm de altura e 45º de inclinação. Com a finalidade de se avaliar a variabilidade espacial da DPM, sensores eletrônicos de DPM foram distribuídos no dossel de três culturas: algodão, banana e café. As medidas obtidas nessas culturas foram comparadas com as fornecidas por sensor de placa em posição padrão. A estimativa da DPM foi feita por meio dos seguintes modelos: NHUR > 87%, CART, DPO e limiar estendido de umidade relativa para os períodos seco e chuvoso. As medidas obtidas por sensores cilíndricos sobre gramado apresentaram boa acurácia e precisão. A variação do ângulo de instalação não demonstrou ter efeito expressivo sobre a medida dos sensores cilíndricos para as condições locais. Contudo, é recomendável inclinar o sensor cilíndrico, uma vez que, trabalhos anteriores demonstram que esse pode superestimar a DPM quando instalado na horizontal. A avaliação da variabilidade espacial da DPM demonstrou que essa variável é influenciada pelas condições determinantes do microclima das culturas. O padrão de variação da DPM foi distinto para cada uma das culturas. Na cultura do algodão não foram observadas variações expressivas da DPM. Já no cafeeiro a DPM foi mais longa nas partes baixas da planta, enquanto que na cultura da banana essa foi mais longa no topo da cultura. Foram obtidas boas relações entre a DPM medida sobre gramado e aquela obtida no topo das culturas, demonstrando que é possível estimar tal variável por meio de dados obtidos em posto meteorológico. Os modelos NHUR > 87%, CART e DPO forneceram boas estimativas da DPM com erro absoluto médio variando de 1,4 a 2,8 h nos dois períodos avaliados. Durante a estação seca, os três primeiros modelos tenderam a subestimar a DPM. O modelo do limiar estendido de umidade relativa foi o que apresentou o pior desempenho entre os modelos avaliados, não sendo recomendável sua aplicação para condições semelhantes às deste estudo. / Leaf wetness duration (LWD) is a very important variable for plant disease epidemiology, since it plays an important role in some epidemiological processes. So its determination is essential for the understanding of the climate and plant disease relationship. Therefore, the objectives of this study were: to determine the standard deployment for cylindrical LWD sensors over turfgrass; to assess the spatial variability of this variable in three different crops; to relate the LWD measured at three different crop canopies to that obtained in a weather station; and to compare the LWD estimated by empirical model with that measured by electronic sensors. Before the field assessments, all electronic sensors were painted with white latex paint and submitted to a heat treatment. After this first stage, all cylindrical sensors where installed over turfgrass at 30-cm height deployed facing south. Firstly, all cylindrical sensors were deployed at horizontal in order to assess the variability among them. After that, five different deployment angles were tested. The measurements provided by those sensors were compared with the standard measurement, provided by flat plate sensors at 30-cm height and deployed at 45º. In order to assess the LWD spatial variability, electronic sensors were placed in three different crop canopies: cotton, banana and coffee. The measurements obtained in those crops were compared with LWD measured by flat plate sensors in a standard deployment over turfgrass. LWD were estimated using the following models: NHRH>87%, CART, DPD e extended threshold of relative humidity, for the dry and wet seasons. The measurements provided by cylindrical sensors over turfgrass had good accuracy and precision. The change in the angle of sensor deployment had no effect on LWD measured by cylindrical sensors, for the studied conditions. However, cylindrical sensors should not be deployed at horizontal because previous studies showed that they could overestimate LWD when deployed at horizontal. The LWD spatial variability assessment showed that this variable is dependent on the plant and/or crop conditions, which control the canopy microclimate. The pattern of variation of LWD was different for each crop assessed. In the cotton crop, LWD variations were negligible. On the other hand, in the coffee crop LWD was longer in the lower parts of the canopy while in the banana crop it was longer in the top of the canopy. A good correlation between LWD measured over turfgrass and that obtained in the crop top was achieved, which demonstrates that it is possible to estimate LWD using weather station data. The models NHRH>87%, CART, DPD provided good estimates of LWD with mean absolute error ranging from 1.4 to 2.8 h in both dry and wet periods. During the dry season, those models overestimated the LWD. The extended threshold model had the worst performance in relation to the other models, so it is not advised to use this model for similar climate conditions to this study.

<p>Elevated temperatures accompanying climate warming are expected to have adverse effects on sensitive lichen species. This premise was examined by measuring the sensitivity of different lichen species to elevated temperatures in the laboratory and in the field. Laboratory studies involved the exposure of nine hydrated lichen species (Xanthoparmelia austro-africana, X. hyporhytida, Xanthoparmelia sp., Xanthomaculina hottentotta, Teloschistes capensis, Ramalina sp., Flavopuntelia caperata, Lasallia papulosa, Parmotrema austrosinensis) collected from sites of different aridity and mean annual temperature for 2 hourly intervals to temperatures ranging from 24&ordm / C to 48&ordm / C in a forced daft oven and measuring their respiration rates and maximum quantum yield of PSII. Field studies involved simultaneous hourly measurements of ground surface air temperatures and Lichen effective quantum yield of PSII of hydrated lichen species populations under ambient and artificially modified environmental conditions.</p>

<p>Elevated temperatures accompanying climate warming are expected to have adverse effects on sensitive lichen species. This premise was examined by measuring the sensitivity of different lichen species to elevated temperatures in the laboratory and in the field. Laboratory studies involved the exposure of nine hydrated lichen species (Xanthoparmelia austro-africana, X. hyporhytida, Xanthoparmelia sp., Xanthomaculina hottentotta, Teloschistes capensis, Ramalina sp., Flavopuntelia caperata, Lasallia papulosa, Parmotrema austrosinensis) collected from sites of different aridity and mean annual temperature for 2 hourly intervals to temperatures ranging from 24&ordm / C to 48&ordm / C in a forced daft oven and measuring their respiration rates and maximum quantum yield of PSII. Field studies involved simultaneous hourly measurements of ground surface air temperatures and Lichen effective quantum yield of PSII of hydrated lichen species populations under ambient and artificially modified environmental conditions.</p>

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The presence of dew at fungicide spray might change de efficiency. So, the work was carried out to evaluate changes on fungicides efficiency on control of wheat diseases due to presence of dew on leaf surface at the moment of spray. In addition, the time of spray and gallonage of the product was considered. Two experiments were carried out at Itaara RS. The first experiment was structured based on three factorial design which factors were fungicides, nozzles (hollow cone, flat fan and twin jet) and dew (presence or absence). It was used the gallonage of 200 L/ha. The second experiment considered the time of spray and fungicide gallonage (60, 80 and 100 L/ha). The fungicide spray was not influenced by the presence of dew on leaf surface at the moment of application since the nozzles produce very small droplets with no wash out. Application of fungicides with no dew on the leaf surface produced good disease control. However, the nozzle utilized should produce small droplets. Fungicide application with a gallonage of 100 L/ha showed efficiency if temperature, humidity and wind velocity were adequate to the spray. / A presença de orvalho no momento das aplicações de fungicidas pode interferir ou não na eficiência agronômica dos produtos. Assim, o presente trabalho teve como objetivo avaliar a eficiência da aplicação de fungicidas na presença e/ou ausência de orvalho no controle de doenças foliares na cultura do trigo bem como avaliar a influência do horário de aplicação e do volume de calda utilizado sobre a eficácia de fungicidas no controle de manchas foliares na cultura do trigo. Foram instalados dois experimentos em Itaara RS. O primeiro foi estruturado com base na interação de três fungicidas, três tipos de pontas de pulverização (cone, leque, duplo leque), presença ou ausência de orvalho na planta submetida aos fungicidas. Para aplicação dos fungicidas foi utilizado vazão de 200 L/ha. No segundo experimento foram avaliados diversos fatores da aplicação como horários e volumes de calda (60, 80 e 100 L/ha). Os resultados obtidos mostraram que as aplicações dos fungicidas não foram influenciadas pela presença de orvalho, quando utilizadas pontas que produziram gotas do tipo muito fina e que não causaram escorrimento dos fungicidas. Aplicações de fungicidas na ausência de orvalho apresentaram bom controle quando as pontas utilizadas produziram gotas classificadas como finas. Aplicações de fungicidas com a utilização de 100 L/ha se tornaram eficientes quando aplicadas sob condições adequadas de temperatura, umidade e velocidade do vento.

The beginning of wetness and the end of leaf drying in potato crop was determined aiming to compare observed values of wetness duration with values estimated from meteorological data and from mathematical models. Three growing seasons with potato were performed at the experimental area of the Crop Science Department of the Federal University of Santa Maria, from 05/03 to 07/06/2004, from 23/07 to 20/10/2004, and from 10/03 to 09/06/2005. Plants were grown at a 0.3x0.8 m spacing. The duration of the leaf wetness was observed visually in the 2004 growing seasons and with six electronic wetness sensors in the 2005 growing season. Meteorological data were measured in an automated weather station installed at 1.5 m above the canopy and a datalogger with psycrometric sensors installed within the canopy (0.1 m height), and above it at 0.4 m, 1.0 m and 1.5 m heights in 2004 and at 0.5 m and 1.5 m heights in 2005. Net radiation was also measured above the canopy. For estimating the duration of the wetness period, the relative humidity thresholds of ≥80%, ≥85%, ≥87%, ≥90%, and ≥87% with an extension up to values of 70% relative humidity. This extension for relative humidity to values of 70%, considered that the beginning of leaf wetness was assumed when a minimum increase of 3% in relative humidity occurred in the 70% and 87% range, during half an hour, and the end of drying was assumed when a decrease of relative humidity greater than 2% occurred in half an hour in the range of 87% and 70% relative humidity. In addition, estimates from the difference of temperature and dew point temperature, and vapor pressure deficit at different heights were performed after defining the thresholds for the moments of beginning of wetness and end of leaf drying. Estimates were also performed with CART model, leaf energy budget model, and Penman model. Visual observations showed that, regardless of the time of the year, wetness and drying of leaves lasts about 1h15min and 3h at evening and dawn, respectively, when conditions are favorable to both processes. It was verified that the duration of leaf wetness can be estimated using the 87% relative humidity threshold with an extension down to 70% measured in the canopy at 1.5 m height. It was also verified that the 90% relative humidity threshold above canopy is not appropriated to estimate the dew wetness period, but this threshold can be used when is measured at 0.1 m within the canopy and so is the 87% relative humidity threshold. CART model with correction of wind speed to the top canopy can be used to estimate the wetness period, with equivalent results to the relative humidity at 1.5 m height approach. The leaf energy budget model is the most appropriated for estimating dew wetness period in a potato canopy, even though this model needs additional calculation and meteorological variables compared to others models. / Determinou-se o início do molhamento e o término da secagem das folhas da cultura da batata com o objetivo de realizar a comparação dos valores reais da duração do período de molhamento por orvalho com os valores estimados a partir da utilização de dados micrometeorológicos e de modelos matemáticos. Foram realizados três cultivos de batata, na área experimental do Departamento de Fitotecnia da Universidade Federal de Santa Maria, nos períodos de 05/03 a 07/06/2004, de 23/07 a 20/10/2004 e de 10/03 a 09/06/2005. As plantas foram cultivadas distanciadas de 0,3 m entre si e de 0,8 m nas fileiras. A determinação da duração do período de molhamento foliar foi realizada por observação visual nos cultivos de 2004 e por seis sensores eletrônicos de molhamento no cultivo em 2005. Os elementos meteorológicos foram obtidos através de uma estação automática da marca μ-Metos instalada a 1,5 m no interior dos cultivos e de um datalogger com sensores psicrométricos instalados no interior do dossel (0,1 m de altura) e acima deste nas alturas de 0,4 m, 1,0 m e 1,5 m em 2004 e de 0,5 m e 1,5 m em 2005, além da medição do saldo de radiação acima do dossel. Na estimativa da duração do período de molhamento foram utilizados os limites de umidade relativa do ar ≥80%, ≥85%, ≥87%, ≥90% e ≥87% com a extensão até valores de 70%, sendo considerado início do molhamento foliar o momento em que, entre os valores de 70% e 87% de umidade relativa do ar, ocorreu um incremento mínimo de 3% em meia hora e o término da secagem quando, entre 87% e 70% de umidade relativa do ar, ocorreu um decréscimo maior do que 2% em meia hora. Foram obtidas ainda estimativas através da diferença entre a temperatura e a temperatura do ponto de orvalho do ar e do déficit de pressão de vapor do ar nas diferentes alturas, após a definição dos seus limites para os momentos de início do molhamento e de término da secagem das folhas. Também foram obtidas estimativas através do modelo CART e dos modelos do balanço de energia de folhas individuais e do modelo de Penman. A partir do acompanhamento visual foi possível verificar que, independente da estação do ano, o processo de molhamento e de secagem das folhas dura em torno de 1h15min e 3h, no anoitecer e na manhã, respectivamente, quando ocorrem condições favoráveis para ambos os processos. Foi verificado que a duração do período de molhamento foliar pode ser estimada a partir do limite de umidade relativa ≥87% com a extensão dos valores até 70%, medidos no cultivo a 1,5 m de altura do solo. Verificou-se também que o limite de 90% de umidade relativa do ar medida acima da cultura não é adequado para estimar o período de molhamento por orvalho, mas pode ser utilizado quando a medição é feita a 0,1 m de altura em meio às plantas, da mesma forma que o limite de 87%. Verificou-se ainda que o modelo CART com correção da velocidade do vento para o nível do topo das plantas pode ser utilizado na estimativa do período de molhamento, com resultados equivalentes à umidade relativa medida a 1,5 m de altura e que o modelo do balanço de energia das folhas é o mais adequado para estimar o período de molhamento por orvalho em um dossel de plantas de batata, embora seja necessário utilizar um número maior de cálculos e de variáveis meteorológicas do que nos outros modelos.

Magister Scientiae (Biodiversity and Conservation Biology) / Elevated temperatures accompanying climate warming are expected to have adverse effects on sensitive lichen species. This premise was examined by measuring the sensitivity of different lichen species to elevated temperatures in the laboratory and in the field. Laboratory studies involved the exposure of nine hydrated lichen species (Xanthoparmelia austro-africana, X. hyporhytida, Xanthoparmelia sp., Xanthomaculina hottentotta, Teloschistes capensis, Ramalina sp., Flavopuntelia caperata, Lasallia papulosa, Parmotrema austrosinensis) collected from sites of different aridity and mean annual temperature for 2 hourly intervals to temperatures ranging from 24ºC to 48ºC in a forced daft oven and measuring their respiration rates and maximum quantum yield of PSII. Field studies involved simultaneous hourly measurements of ground surface air temperatures and Lichen effective quantum yield of PSII of hydrated lichen species populations under ambient and artificially modified environmental conditions. / South Africa