Orientador: Marco Eustaquio de Sa / Banca: João Antonio da Costa Andrade / Banca: Kuniko Iwamoto Haga / Banca: Gisele Herbst Vazquez / Banca: Neli Cristina Belmiro dos Santos / Resumo: O uso de sementes com alto nível de vigor é fundamental para o sucesso de um empreendimento agrícola, pois apresentam melhor desempenho em campo, resultando em maior produção. O objetivo do trabalho foi verificar o nível do vigor em sementes de três híbridos de milho submetidas ao envelhecimento acelerado e seus desempenhos em laboratório e em campo. Para tanto sementes dos híbridos AG-5020, AG-8088 e BG-7049 foram envelhecidas artificialmente à 41oC por 0, 48 e 72 horas e secadas em estufa à 38 °C/48 horas para a formação dos diferentes lotes. Experimento 1 - No laboratório, verificou-se o nível de vigor e o desempenho das sementes dos diferentes lotes por meio de análises de germinação, primeira contagem, deterioração controlada, tetrazólio, comprimento de raiz primária e mesocótilo, número de raízes/plântula, massa de matéria seca de plântula e emergência em solo. Experimento 2 - No campo as sementes foram semeadas manualmente em parcelas de 8 linhas de 5m, espaçamento de 0,5m e densidade de 80.000 plantas ha-1. Verificou-se o nível de vigor e o desempenho das plantas em campo pelas avaliações de características morfológicas das plantas, caracteres da espiga e componentes de produtividade. O delineamento experimental foi o inteiramente casualizado com os tratamentos obtidos da combinação 3 x 3 (híbridos x níveis de vigor) com quatro repetições. Em laboratório as sementes mais vigorosas apresentaram melhores desempenhos e em campo proporcionaram a obtenção de maior produtividade, o que se deve principalmente ao maior estande final obtido. As características das plantas e das espigas estão relacionadas ao genótipo de cada híbrido não se verificando efeito do vigor das sementes / Abstract: The use of seeds with high level of vigor is fundamental to the success of an agricultural development, since its have better performance in the field, resulting in increased production. The objective of this study was to assess the level of vigor in seeds of three maize hybrids submitted to accelerated aging and their performance in laboratory and field. Seeds of AG-5020, AG-8088 and BG-7049 were artificially aged at 41°C for 0, 48 and 72 hours and dried in an stove at 38 °C /48 hours for the formation of the different lots. Experiment 1 - in the laboratory, we found the level of vigor and the performance of different seed lots by means of analysis of germination, first count, controlled deterioration, tetrazolium, length of primary root and mesocotyl, number of roots/seedling, seedling mass dry matter and seedling emergence in soil. Experiment -2 the seeds were manually sown in plots of 8 rows of 5m, 0,5 m spacing and density of 80000 plants ha-1. The level of vigor and performance of plants in the field evaluations of morphological characteristics of plants, components and characters of the spike in productivity. The experimental design was completely randomized treatments obtained with the combination 3 x 3 (hybrid x vigor levels) with four replications. In the laboratory the most vigorous seeds showed better performances and the field higher productivity, which is mainly due to higher final stand. As characteristics of plants and spike are related to the genotype of each hybrid was not observed effect of vigor seeds / Doutor

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / The mineralogical composition of the Beige Bahia (BB) limestone was characterized by petrographic analysis, XRD, total-rock (TR) chemical analysis, and SEM on figurative elements of lytic texture. The results demonstrated that this type of calcrete is dolomitic (dolomite > 10% in TR), reaching over 50% in its lumpy features. The matrix is primarily calcite, whereas quartz (< 5% TR) and palygorskite are the most common accessory minerals. The changing mechanisms of the BB, as a building covering, were investigated from the loss of brightness, using in natura polished boards in bench, for comparison with observations carried out in situ in a metropolitan coastal area (Recife-PE), under humid tropical climate. Tests of accelerated changeability involving atmospheres with saline saturation (NaCl) and in SO2, attacks by acid solutions (HCl, HNO3, H2SO4), rain water and sea water, were conducted according to the Brazilian Association of Technical Standards/ABNT or experimentally, involving in natura polished test specimen. By considering as critical a brightness intensity &#8804; 40, whether for test specimen or for applications carried out in situ, a reliable prediction is possible based on bench data. In most cases, this critical level is reached around the third testing cycle, corresponding to ten years in in situ changing conditions. The most active mechanisms were the gas chamber with SO2 saturation, and the sea water; and the critical brightness was reached between 2 and 2.5 cycles in bench. The set of results did not confirm if the ferric staining and black crusts are of lithogenic origin, whereas âwhite crustsâ are made of gypsum (CaSO4.H2O), by the reaction of H2SO4 with the calcite surface of the BB. Therefore, the inadequacy of the application of this product on external coverings is confirmed, particularly in the presence of sea spray or in metropolitan situations, where the atmosphere is mpregnated with SO2. / A composiÃÃo mineralÃgica do calcÃrio Bege Bahia (BB) foi caracterizada por anÃlise petrogrÃfica, DRX, anÃlises quÃmicas sobre rocha-total (RT), e MEV sobre elementos figurados da textura lÃtica. Os resultados demonstraram que este tipo de calcrete à dolomÃtico (dolomita > 10% em RT), atingindo mais de 50% em suas feiÃÃes grumosas. A matriz à essencialmente calcÃtica, enquanto quartzo (< 5% RT) e palygorskita sÃo os minerais acessÃrios mais frequentes. Os mecanismos de alteraÃÃo do BB, como revestimento de edificaÃÃes, foram investigados a partir da perda de brilho, utilizando-se placas lustradas in natura em bancada, para comparaÃÃo com observaÃÃes in situ em Ãrea litorÃnea metropolitana (Recife-PE), sob clima tropical Ãmido. Ensaios de alterabilidade acelerada envolvendo atmosferas com saturaÃÃo salina (NaCl) e em SO2, ataques por soluÃÃes Ãcidas (HCl, HNO3, H2SO4), Ãgua de chuva e Ãgua do mar, foram conduzidos segundo normas ABNT ou experimentalmente, envolvendo corpos de prova lustrados in natura. Considerando-se crÃtica uma intensidade de brilho &#8804; 40, seja para os corpos de prova quanto em aplicaÃÃes in situ, torna-se possÃvel uma confiÃvel prediÃÃo a partir dos dados de bancada. Na maior parte dos casos, este nÃvel crÃtico à atingido em torno do terceiro ciclo dos ensaios, correspondendo a 10 anos em condiÃÃes de alteraÃÃo in situ. Os mecanismos mais atuantes foram a cÃmara de gÃs com saturaÃÃo em SO2 e a Ãgua do mar, sendo o brilho crÃtico atingido entre 2 a 2,5 ciclos em bancada. O conjunto dos resultados nÃo confirmou se manchamentos fÃrricos e crostas negras sÃo de origem litogÃnica, enquanto que âcrostas brancasâ sÃo constituÃdas de gipsita (CaSO4.H2O), por reaÃÃo de H2SO4 com a superfÃcie calcÃtica do BB. Assim, confirma-se a inadequaÃÃo de aplicaÃÃo deste produto em revestimentos externos, particularmente em presenÃa de spray marinho ou situaÃÃes metropolitanas, onde a atmosfera apresenta-se impregnada com SO2.

O objetivo principal deste trabalho é a análise e possível otimização de um projeto de válvulas de esfera. É apresentado um estudo para determinação do torque de acionamento de válvulas de esfera industriais, bem como um estudo de vida útil das válvulas. Os estudos foram realizados utilizando projeto de experimentos e permitiram a construção de modelos de previsão de torque e de previsão de vida útil. A previsão de torque é fundamental para possibilitar a otimização do projeto das válvulas, na fase de desenvolvimento do produto. O uso dos modelos permitiu a determinação do ajuste ótimo, levando em conta pressão, temperatura, esmagamento das sedes, torque de aperto na porca da haste e torque de acionamento desejado. Já os estudos de vida útil são importantes para informar à empresa o número de ciclos até o vazamento. Os resultados do estudo, realizado através de ensaios acelerados, permitiram a construção de modelos de confiabilidade associada ao número de ciclos de operação, permitindo assim a avaliação e possível melhoria do projeto das válvulas. / The main objective of this dissertation is the analysis and optimization of a ball valve project. A study for determining the operational torque of industrial ball valves as well as a life study of valves are presented. The studies were performed using design of experiments and allowed the construction of torque and life prevision models. The prevision of torque is fundamental to enable project optimization on the phase of product development. Results allowed the definition of an optimal setting regarding pressure, temperature, seats tightening, stem nut tightening torque and the desired operational torque. Further, the life studies are helpful to inform the company the number of cycles until leakage. Results, obtained through accelerated tests, allowed the construction of reliability models associated to the number of operational cycles, conducting to valve design evaluation and optimization.

Traditionally, flexible pavement design relies on past experience and semi-empirical methods developed through a combination of element testing and modelling. Element testing in this area especially, has centred on the performance of clean sands. This is in conflict with actual practice where a wide range of fines and soil gradations could be present in a real-world project. This research investigates the characteristics of natural sands and examines the influence of these marginal materials in pavement design using element testing and controlled modelling of an actual flexible pavement system. The element tests concentrated on separate, natural soils sourced from Kazakhstan which had similar mineralogy, but varying amounts of fines. One of the key parameters examined was equivalent void ratio and its efficiency to account for the behaviour change in granular materials which comes from increased fines content. Starting with monotonic triaxial results combined with strength-dilatancy methods it was shown that prediction of shear strength in a silty-sand could be improved by 13%. Incorporating this finding into repeat load triaxial tests, the transitions between elastic, plastic, and ratcheting failure behaviours (i.e. shakedown boundaries), commonly used to help predict the lifespan of a flexible pavement, were examined. It was seen that cycling a silty-sand, the stress path and yield surface could change depending on the fines content. The Cambridge Airfield Pavement Tester (APT) was designed and constructed to measure permanent subgrade deformation resulting from various surface loads. The number of input variables required to design flexible pavements is one of the most frequently stated problems in the field; variation of aircraft types, environmental conditions, and materials makes mechanistic design of the soil foundation problematic. Accordingly physical pavement modelling continues to be the only experimental method that allows input parameters and material characteristics to be examined simultaneously. Digital image correlation (DIC) was incorporated into the system; the first time this technology has been used in flexible pavement research. A Null Pressure System was also installed to measure soil stress distributions. It was observed that the critical failure mechanisms for thin and thick surficial layers are different, resulting in changes in the rates of surface rutting. Finally, by combining element and APT results, knowledge of the causal relationships between subsurface deformation and failure mechanisms in flexible pavement were advanced. In-situ soils, which are frequently incorporated into subgrade designs, were found to have a substantial role in the serviceability of the pavement. Correlations between element tests and APT results highlighted the complicated loading and boundary conditions present in a pavement.

O objetivo desse estudo foi avaliar sistematicamente o efeito da escovação simulada e do envelhecimento artificial acelerado (EAA) sobre estabilidade de cor e rugosidade de superfície de compósitos odontológicos de nanopartículas (Z350 - 3M ESPE) e híbrido (Tetric N-Ceram - Ivoclar Vivadent). Foram confeccionados 24 corpos-de-prova (12mm de diâmetro X 2mm de espessura) para cada compósito e uma cerâmica de revestimento (IPS e.max Ceram - Ivoclar Vivadent) como controle. Após sua confecção, os corpos-de-prova foram polidos com lixas d&lsquo;água em abrasividades decrescentes (compósitos = 600, 1200 e 2000 e cerâmica = 100, 320, 1200 e 2000). Em seguida, foram realizadas leituras iniciais de cor (Espectrofotômetro PCB 6807) e rugosidade de superfície (Rugosímetro Surfcorder SE 1700 - Kosakalab). As amostras foram separadas em 3 grupos (n=8), segundo o tratamento a que foram submetidas: Grupo 1: EAA; Grupo 2: escovação mecânica com dentifrício RDA* 68 (Colgate); e Grupo 3: escovação mecânica com dentifrício RDA* 180 (Colgate Total Plus Whitening). Após 480 horas de EAA e em intervalos de 41 minutos de escovação (=14.600 ciclos) até 205 minutos novas leituras de cor e rugosidade de superfície foram realizadas. Amostras inicialmente submetidas a EAA (n=4) receberam escovação mecânica com dentifrício RDA* 68 e 180, conforme metodologia descrita anteriormente e novas leituras de cor e rugosidade foram obtidas. Os dados (antes e após os testes) foram analisados estatisticamente (2-way ANOVA análises repetidas, Bonferroni, p<0,05) e verificou-se que houve maior alteração de cor dos compósitos quando submetidos a EAA com diferença estatisticamente significante (p<0,05) em relação à escovação mecânica. Não houve diferença estatisticamente significante (p>0,05) na estabilidade de cor dos materiais quando comparadas as abrasividades dos dentifrícios, porém esse fator foi significante para a alteração de rugosidade de superfície (p<0,05), sendo maior quando os materiais foram escovados com RDA* 180. Quanto ao tempo de escovação, não houve diferença estatisticamente significante (p>0,05) para a alteração de cor e de rugosidade de superfície dos materiais, o mesmo ocorrendo para amostras escovadas após EAA. Conclui-se que o EAA interfere na estabilidade de cor e a escovação simulada nas alterações de rugosidade de superfície dos compósitos, independente do tempo de utilização do dentifrício, sendo maior para dentifrícios mais abrasivos. Além disso, a abrasividade e o tempo de utilização do dentifrício não alteram a capacidade de remoção do manchamento e a rugosidade de superfície de compósitos. / The purpose of this study was to evaluate the effect of simulated toothbrushing and accelerated artificial aging (AAA) on color stability and surface roughness of nanofill (Z350 - 3M ESPE) and hybrid (Tetric N-Ceram - Ivoclar Vivadent) composites. Twenty-four diskshaped specimens (12mm in diameter X 2 mm thick) were made for each composite and one feldspatic ceramic (IPS e.max Ceram - Ivoclar Vivadent) as a control. The specimens were polished with decreasing abrasiveness sandpapers (composites = 600, 1200, 2000 and ceramic = 100, 320, 1200, 2000). Then, initial readings were taken on color (Spectrophotometer PCB 6807) and surface roughness (Rugosimeter Surfcorder SE 1700 - Kosakalab). The samples were separated in 3 groups (n=8) according to the submitted treatments: Group 1: AAA; Group 2: mechanical brushing with dentifrice RDA* 68 (Colgate); and Group 3: mechanical brushing with dentifrice RDA* 180 (Colgate Total Plus Whitening). New readings on color and surface roughness were taken after 480 hours of AAA and in intervals of 41 minutes of brushing (=14.600 cycles) until 205 minutes. The samples initially submitted to AAA (n=4) received mechanical brushing with dentifrice RDA* 68 and 180, according to previously described methodology and new readings on color and roughness were taken. Data (before and after tests) were statistically analyzed (2- way ANOVA repeated measures, Bonferroni, p<0,05) and it was observed a higher composite color alteration compared with mechanical brushing when submitted to AAA with a statistically significant difference (p<0,05) between them. There was no statistically significant difference (p>0,05) on color stability of materials when the dentifrices abrasiveness were compared, but it was significant for surface roughness degradation (p<0,05), higher when materials were brushed with RDA* 180. Regarding time brushing, there was no statistically significant difference (p>0,05) for color alteration and roughness surface of materials and the same occurred for samples brushed after AAA. It was concluded that AAA interferes on color stability and the simulated brushing on surface roughness degradation of composites regardless the time of used dentifrice, but it was higher for more abrasive dentifrices. Moreover, abrasiveness and time of used dentifrice do not alter the capacity of staining removal and the surface roughness of composites.

This study used simulated results to evaluate four alternative methods of computing confidence intervals for class means in the context of student evaluations of teaching in a university setting. Because of the skewed and bounded nature of the ratings, the goal was to identify a procedure for constructing confidence intervals that would be asymmetric and not dependent upon normal curve theory. The four methods included (a) a logit transformation, (b) a resampling procedure, (c) a nonparametric, bias corrected accelerated Bootstrapping procedure, and (d) a Bayesian bootstrap procedure. The methods were compared against four criteria including (a) coverage probability, (b) coverage error, (c) average interval width, and (d) the lower and upper error probability. The results of each method were also compared with a classical procedure for computing the confidence interval based on normal curve theory. In addition, Student evaluations of teaching effectiveness (SET) ratings from all courses taught during one semester at Brigham Young University were analyzed using multilevel generalizability theory to estimate variance components and to estimate the reliability of the class means as a function of the number of respondents in each class. The results showed that the logit transformation procedure outperformed the alternative methods. The results also showed that the reliability of the class means exceeded .80 for classes averaging 15 respondents or more. The study demonstrates the need to routinely report a margin of error associated with the mean SET rating for each class and recommends that a confidence interval based on the logit transformation procedure be used for this purpose.

The purpose of this study was to determine if a difference existed between TCAP scores of students who used the Accelerated Reader (AR) program and students who used Sustained Silent Reading strategy (SSR) as measured by the Tennessee Comprehensive Assessment Program (TCAP). The variables of grade level (6th, 7th, and 8th), gender, and socioeconomic status (free- or reduced- price meals program) were considered. The population consisted of 108 6th graders who attended a Cocke County school or a McMinn County school in Tennessee. Data were obtained from the TCAP for 3 consecutive years beginning in 2004-2005 for students who completed the tests all 3 years. A t test for independent samples and analysis of variance (ANOVA) were used to determine if there was a difference on associations and interactions between variables. The researcher's investigation of the reading achievement of students who used Accelerated Reader and those who used Sustained Silent Reading should assist educators in planning for supplemental reading instruction. The information gathered from this research might be beneficial to other school systems when determining which method of reading instruction to use to increase students' reading achievement. The findings indicated the students who used the Accelerated Reader program had an increase in reading-language arts scale scores for 3 consecutive years. The findings of this study also revealed that gender had no significance on student achievement for 6th graders. The findings did indicate a significant interaction between gender and type of program used during 7th and 8th grades. Females who used the Accelerated Reader program outscored males who used the program. The findings of this study also determined that socioeconomic status had no association with TCAP scores during the 6th, 7th, or 8th grades.

The objective of this study was to evaluate ewe and lamb performance in an accelerated lamb production system, and to compare the performance and lamb output between a conventional and an accelerated lamb production system. In the “Conventional” system, ewes were bred in March to lamb in August. The “Accelerated” system was based on the “STAR” system (Lewis et al., 1996), in which there were five breeding periods within each year. In the current experiment these were 14th January, 28th March, 9th June, 21st August and 2nd November. Progesterone was used to synchronise the breeding periods and during the non-breeding season, eCG was used to induce reproductive activity. Lambing began on each of these dates and weaning was 73 days later, coinciding with the next breeding period. The experiment ran over a three-year period beginning with breeding in March 2003 and was complete with the weaning of lambs from the January 2006-bred ewes. This resulted in 15 lambing and breeding periods over the three years in the Accelerated system and three lambing and breeding periods in the Conventional system. Average pregnancy rates were lower in the Accelerated system than in the Conventional system. Lamb growth rates were similar between the two systems, although lamb live weights at weaning were lower in the Accelerated system due to the age of the lambs at weaning (average = 69 vs 96 days). More lambs were born and weaned, resulting in more kilograms of lamb weaned in the Accelerated system relative to the Conventional system over the experimental period (26,200 vs 24,300 kg). Labour input was 35% higher in the Accelerated system, or 13% higher per lamb weaned. Average annual ewe energy requirements were 6% higher in the Accelerated system. Ewe energy requirements per kilogram of lamb weaned was lower (6%) in the Accelerated system due to more breeding and lambing periods per ewe per year. Laparoscopic observation of ewes’ ovaries at each breeding period revealed that most ewes had active ovaries and were therefore capable of successfully producing a viable foetus. In a subsequent experiment, blood samples were collected for analysis of progesterone concentrations from ewes bred during the spring and autumn breeding periods. Observations of data indicated that a small number of ewes conceived and lost their conceptus, or had abnormal corpora lutea. Results suggested that pregnancies were failing due to a lack of an appropriate signal from the embryo to the dam/uterus. Exposing Romney ewes to an artificial lighting regimen was unsuccessful for inducing reproductive activity during spring. In another experiment, melatonin implants administered to Romney ewes in spring and used in conjunction with eCG and progesterone, resulted in 61% more lambs born per ewe treated, compared to eCG and progesterone alone. This result indicated that melatonin implants, used with eCG and progesterone may be a suitable method for improving reproductive performance in sheep bred out of season in New Zealand. Delaying weaning of lambs and breeding lactating ewes can be used to obtain heavier lamb weaning weights in the Accelerated system. Spring-bred ewes had lambs weaned at either 69 days post partum or 90 days post partum. Reproductive performance was similar between the two groups of ewes, and lamb live weights in the later weaned group were heavier when lambs were 90 and 120 days of age. This research has shown that accelerated or out-of-season lamb production is an option for some New Zealand sheep farmers. However, the mechanisms associated with reproductive seasonality and methods of successfully circumventing this seasonality require further attention in order to achieve optimum reproductive performance.

Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.

Medical cost has received increasing interest recently in Biostatistics and public health. Statistical analysis and inference of life time medical cost have been challenging by the fact that the survival times are censored on some study subjects and their subsequent cost are unknown. Huang (2002) proposed the calibration regression model which is a semiparametric regression tool to study the medical cost associated with covariates. In this thesis, an inference procedure is investigated using empirical likelihood ratio method. The unadjusted and adjusted empirical likelihood confidence regions are constructed for the regression parameters. We compare the proposed empirical likelihood methods with normal approximation based method. Simulation results show that the proposed empirical likelihood ratio method outperforms the normal approximation based method in terms of coverage probability. In particular, the adjusted empirical likelihood is the best one which overcomes the under coverage problem.