Made available in DSpace on 2014-06-11T19:30:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-02-03Bitstream added on 2014-06-13T18:59:50Z : No. of bitstreams: 1 pantuzi_ta_me_guara.pdf: 568273 bytes, checksum: a42f0347150ae7b5aed4fe7d75bf9bcc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esse trabalho mostra modelos teóricos com soluções numéricas para o comportamento térmico de um armazenador de calor sensível usando água como fluído de trabalho. Um modelo bidimensional baseado nas equações de conservação de massa, conservação da quantidade de movimento e conservação de energia é usado para simular o fenômeno da estratificação. Para a solução numérica foi utilizado o método de diferenças finitas. Foi analisada a degradação da estratificação na condição de resfriamento natural com tanque estacionário, e alguns parâmetros que influenciam os processos de carregamento e descarregamento também foram simulados pela solução numérica. Em uma comparação feita entre um armazenador estratificado e uma armazenador homogêneo, mostrou-se que a eficiência do armazenador estratificado é maior. A razão de aspecto igual a quatro foi a melhor encontrada para a operação de extração. O estudo da velocidade, nas operações de carregamento e descarregamento, mostrou que com o aumento da mesma o tempo de operação diminui, mas este aumento tem um limite para que não ocorra uma diminuição da eficiência. / This work shows theoretical models with solutions for the thermal behavior of a storing one of sensible heat using water as fluid of work. A based bidimensional model in the equations of conservation of the mass, conservation of the amount of movement and conservation of the energy is used to simulate the phenomenon of the stratification. For the numerical solution the method of finite differences was used. The degradation of the stratification in the condition of natural cooling with stationary tank was analyzed, and some parameters that also influence the shipment processes and unloading had been simulated by the numerical solution. In storing a storing comparison made between estratificado and a homogeneous one, one revealed that the estratificado efficiency of the storing one is bigger. The reason of equal aspect the four was the best one found for the operation of extration. The study of the speed, in the operations of shipment and unloading, it showed that with the increase of the same o running time it diminishes, but this increase has a limit so that a reduction of the efficiency does not occur.

O presente estudo visa dar luz sobre fenômenos ainda pouco explorados que ocorrem durante a estratificação em leitos de jigagem, bem como sobre novas possibilidades de aplicação da técnica. Por meio de testes com misturas de agregados em jigues hidráulico e pneumático descontínuos, foi pela primeira vez examinada a ocorrência de convecção granular em jigues. Os fatores envolvidos em sua formação e a influência sobre a estratificação foram analisados em detalhes. Do mesmo modo, foi examinada a influência da granulometria do leito sobre a estratificação em jigues pneumáticos e a possibilidade de uso do mesmo como um equipamento multi-separador. Os resultados revelam a existência de um fluxo ordenado e estacionário de partículas durante a pulsação do leito, ascendente na porção central e descendente nas bordas do jigue, de modo similar ao fluxo convectivo descritos na literatura para leitos vibrados mecanicamente. Este fluxo convectivo gerou uma distorção no rearranjo do leito estratificado, dando origem a um perfil horizontal de estratificação no qual as partículas leves se concentraram nas bordas e as partículas densas se concentraram preferencialmente na zona central dos estratos. Com base nos resultados, um mecanismo de formação do fluxo convectivo e um modelo preditivo do rearranjo do leito foram propostos. Observou-se também que a diminuição da granulometria e o aumento da distribuição de tamanho dos constituintes do leito teve um efeito positivo sobre a estratificação. Os resultados sugerem que isto pode estar em parte relacionado a maior compactação do leito quando da presença de partículas de menor tamanho. Também, resultados experimentais demonstraram a possibilidade de uso do jigue pneumático para realizar a operação conjunta de separação de materiais rochosos e não rochosos em um único estágio. O desempenho global na remoção de contaminantes não-rochosos foi similar ao de separadores pneumáticos e sistemas de "sorting" automático descritos na literatura. Ainda, a quantidade inicial de contaminantes no sistema teve um efeito desprezível sobre o desempenho. Os resultados obtidos, em particular aqueles relacionados à convecção granular, fornecem novas perspectivas a respeito dos fenômenos envolvidos na estratificação em jigues. Ainda, benefícios práticos podem ser extraídos a partir dos resultados da análise do efeito da granulometria sobre a estratificação e do uso de jigues pneumáticos como multi-separadores. / This study aims to shed some light on some unclear phenomena that occurs during particle stratification in jigs as well as on new possibilities of application of jigging technique. For the first time, the occurrence of granular convection in jigging beds was analyzed by considering the case of hydraulic and pneumatic jigs operating with mixtures of aggregates. The elements involved in the pattern formation and its influence on bed stratification were analyzed in detail. The influence of particle size distribution on bed stratification and the possibility of using pneumatic jigging as a multi-separator were also examined. The experimental results reveal the existence of a steady, ordered flow of particles over bed pulsation, in which particles move upward in the center of the jig bed and downward along the walls of the jig container, similarly to the circulation patterns reported in the literature. The convection gave rise to a distortion in the particle rearrangement, engendering the formation of a horizontal stratification profile in which light particles tended to be concentrated along the walls while dense particles tended to be concentrated preferentially in the center portion of the strata. On the basis of the experimental results, a mechanism of pattern formation and a prediction model were proposed. The results also revealed that the decrease of the particle size and the increase in the particle size distribution had a positive influence on stratification extent. It was suggested by the results that this behavior can be related to the higher bed compaction due to the presence of smaller particles in the bed. Also, experimental results indicated the technical feasibility of the combined use of pneumatic jigging for the removal undesired non-stony materials together with the bed stratification in only one single stage. The reported separation efficiency in the removal of low-density materials was comparable to those of air classifiers and automatic sorting systems. Also, the initial content of contaminants seemed to have a negligible effect on the separation performance. The results obtained, in particular those related to the granular convection, provides new perspectives about the phenomena involved in stratification by jigging. Moreover, practical benefits can be obtained from the results about the influence of particle size on bed stratification and about the usage of pneumatic jigging for multi-separation.

abstract: Two critical limitations for hyperspatial imagery are higher imagery variances and large data sizes. Although object-based analyses with a multi-scale framework for diverse object sizes are the solution, more data sources and large amounts of testing at high costs are required. In this study, I used tree density segmentation as the key element of a three-level hierarchical vegetation framework for reducing those costs, and a three-step procedure was used to evaluate its effects. A two-step procedure, which involved environmental stratifications and the random walker algorithm, was used for tree density segmentation. I determined whether variation in tone and texture could be reduced within environmental strata, and whether tree density segmentations could be labeled by species associations. At the final level, two tree density segmentations were partitioned into smaller subsets using eCognition in order to label individual species or tree stands in two test areas of two tree densities, and the Z values of Moran's I were used to evaluate whether imagery objects have different mean values from near segmentations as a measure of segmentation accuracy. The two-step procedure was able to delineating tree density segments and label species types robustly, compared to previous hierarchical frameworks. However, eCognition was not able to produce detailed, reasonable image objects with optimal scale parameters for species labeling. This hierarchical vegetation framework is applicable for fine-scale, time-series vegetation mapping to develop baseline data for evaluating climate change impacts on vegetation at low cost using widely available data and a personal laptop. / Dissertation/Thesis / M.A. Geography 2013

Incluído no grupo informal \"Clado Novo Mundo\" sensu Huber (2000), o gênero Mesabolivar apresenta distribuição restrita a região neotropical e inclui atualmente 45 espécies válidas. Este gênero e é composto por algumas espécies que habitam a vegetação, troncos e rochas (hábito parietal) e outras que habitam a serapilheira. Foi proposto testar o monofiletismo de Mesabolivar e estudar a evolução do habitat de vida no gênero. Foram realizadas duas análises. A primeira, em escala genérica, objetivou avaliar as relações do \"Clado Novo Mundo\" e o monofiletismo de Mesabolivar. Usando parcimônia Foram encontradas 200 árvores com 498 passos. Não foi encontrada resolução suficiente para encontrar o grupo-irmão de Mesabolivar. O gênero não é monofilético, com três espécies (M. luteus, M. levii e M. cambridgei) relacionadas a outros gêneros. As demais espécies de Mesabolivar formam um grupo monofilético, suportado pelo procurso curvado e presença de cavidade epiginal. A segunda análise, que incluiu 36 espécies descritas e 29 não descritas de Mesabolivar, encontrou 74 mais parcimoniosas com 256 passos. Foram testadas as relações entre medidas morfométricas, para que estas possam ser relacionadas com o habitat. Foi encontrado há uma correlação entre o habitat, tamanho das pernas e formato do abdomem, onde aranhas com abdomem esférico (fiandeiras quase ventrais) e pernas curtas habitam o solo e aranhas com abdomem alongado (fiandeiras subterminais) e pernas longas vivem em vegetação, troncos e rocha (habito parietal). Para realizar inferências em espécies com história natural desconhecida, foi observado que o fêmur, tíbia e metatarso representam bem o tamanho total das pernas, sendo que o metatarso é o mais adequado. Otimizando o habito de vida (com dados diretos ou inferidos pelas medidas/formato do abdomem) foi otimizado no cladograma. A condição plesiomórfica baseada no grupo externo é o habitat parietal. Entretanto, o hábito plesiomórfico para Mesabolivar é ambíguo. O clado mais basal de Mesabolivar é composto por habitantes do solo. O hábito de vida no solo é reconquistado pelo menos duas vezes. São apresentadas descrições resumidas das 29 espécies incluídas nas análises, e duas relacionadas a M. luteus / Belonging to the informal group \"New World Clade\" sensu Huber (2000), Mesabolivar has a Neotropical distribution. Includes nowadays 45 valid species. This genus comprises parietal species (shrubs, logs, trunks and rocks inhabitants) and litter inhabitant species. The Mesabolivar monophyletism was tested, and the evolution of habitat choice was studied. The phylogenetic analysis was conducted in two phases. The first one, at generic scale, tried to reevaluate the \"New World Clade\" internal relationships and verify the monophyly of Mesabolivar. The analysis using parsimony found 200 tree with 498 steps. The resolution did not allow identify the sister group of Mesabolivar. The genus Mesabolivar was found polyphyletic, with three species related to other genera (M. luteus, M. levii and M. cambridgei). All other Mesabolivar species form a monophyletic group. The second analysis included 96 known and 29 unknown Mesabolivar species. Found 74 more parsimonious trees with 256 steps. The relationship between the morfometrical traits and habitat was tested. There is a correlation between habitat, leg length and abdomen shape. Spiders with spherical abdomen (ventral spinnerets) and relatively short legs are litter inhabitants. Spiders with elongated abdomen (subterminal spinnerets) and long legs have parietal habitat. The statistical inference found the metatarsus as the best representative of leg length. Using observation and inference, the habitat was optimized. The plesiomorphic condition in Mesabolivar was ambiguous. The basal clade was composed by litter inhabitants. The litter living habitat was conquered at least two times indenpendently. Was presented 29 reduced descriptions of unprescribed species included in the phylogenetic analysis

Objective Formulation of a clinical practice guideline (CPG) for the use of thromboprophylaxis (TP) in pediatric patients with a central venous catheter (CVC). Participants The development team consisted of five experts and a doctoral candidate acting as the primary author. Evidence The guideline was developed utilizing the Appraisal of Guidelines for Research and Evaluation (AGREE) II framework. A systematic review of the evidence was performed and evidence was graded using the American Academy of Pediatrics (2004) evidence classifications for CPG recommendations. An appraisal team evaluated the guideline quality utilizing the AGREE Plus platform rating the guideline as “highest quality.” Consensus Employing a modified Delphi methodology, members of the development team reviewed available evidence and voted on proposed Key Action Statements (KAS). Consensus is defined as 80% rating the KAS “usually appropriate.” Conclusion Five KAS are included in the final CPG. Each KAS indicates level of evidence, benefit-harm relationship, and level of recommendation. KAS 1. Providers of hospitalized children (0-18 years of age) may assess for VTE risk factors using the Skrocki VTE risk stratification tool if the patient has a CVC. (Evidence Quality:C, Rec. Strength: Option). KAS 2. Providers of hospitalized children should initiate targeted pharmacologic thromboprophylaxis (tpTP) at the time of CVC insertion or hospital admission (if CVC present on admission). (Evidence Quality: B, Rec. Strength: Strong Recommendation) KAS 3. Providers of hospitalized children with a CVC should implement mechanical thromboprophylaxis (mTP) if the child is immobile (Braden Q score <2) or moderate/ high risk for VTE using the Skrocki VTE risk stratification tool and have no contraindications to mTP. (Evidence Quality: B, Rec. Strength: Recommendation). KAS 4. Providers of hospitalized children with a CVC may prescribe systemic pharmacologic thromboprophylaxis (spTP) if the patient is found to be at high risk for VTE using Skrocki VTE risk stratification tool and the patient has no contraindications to spTP. (Evidence Quality: C, Rec. Strength: Option). KAS 5. Providers of hospitalized children should avoid femoral CVCs, multilumen CVCs and/or percutaneous insertion technique if their benefit does not clearly outweigh their risks. (Evidence Quality: B, Rec. Strength: Recommendation).

In this research I first examine how Americans’ perceptions of what it takes to get ahead are influenced by their income and then compare those perceptions to measured levels of intergenerational socio-economic mobility. By better understanding these relationships I hope to gain insight into the paths people see to upward mobility, how this varies by income, and to what extent this belief is reflected in past mobility measurements. Additionally, I compare perceptions of what it takes to get ahead with responses regarding attitudes towards public assistance. The results of such a comparison could have important implications for public policy. The results reveal that there is a significant correlation between income and views of what it takes to get ahead with those at higher income levels perceiving greater levels of opportunity for mobility. Perceptions of opportunity for mobility appear high across all incomes relative to previous measurements of mobility. However, the low income group perceived less opportunity than the middle income group which reflects the pattern of measured levels of mobility. Also, views on the importance of educated parents and working hard are significant predictors of attitudes on public assistance. Belief in the less meritocratic indicators was associated with support for public assistance while belief in the more meritocratic indicators was associated with opposition.

Social stratification research has consistently found persistent inequalities in the academic outcomes of children from different socio-economic status (SES) groups. Research in the sociology of education has shown that students from higher SES groups outperform peers from lower SES groups on various academic indicators as well as make greater academic progress when assessed at two or more separate points in time. Recent evidence from the US has also shown that participation in leisure out-of-school activities (OSA) is among the factors which may contribute to maintaining or even widening these inequalities. Similar evidence is lacking in the UK. The present research focuses on this issue by analysing the role of participation in leisure OSA in the process of reproduction of social inequalities in academic outcomes among British school-aged children. The study draws on social and cultural capital theories to address the following questions: a) Are there differences in participation in OSA among school-aged children in dissimilar SES groups?; b) Taking into account children’s SES, is participation in OSA associated with their academic outcomes?; c) Does the association between participation in OSA and children’s academic outcomes vary across different SES groups? Using data from the third and fourth sweeps of the Millennium Cohort Study (MCS), when cohort members were aged 5 and 7 years old, the research explores participation in three categories of leisure activities; a) social-group activities, b) commercial-public activities, and c) home-centred activities. Children’s academic outcomes are assessed using verbal and non-verbal standardised tests, as well as by teachers’ assessment. The study applied regression models to examine the relationships between children’s SES, participation in OSA and academic outcomes. The statistical analyses were carried out in a multilevel framework which enabled the MCS hierarchical data structure and area variations to be accounted for. The findings suggest that participation in some, but not all leisure OSA is one of the factors which contributes to socio-economic inequalities in educational outcomes among British school-aged children. This is because participation in OSA is associated with better academic performance among all students, however those in high SES groups are more likely to be exposed to such activities. After controlling for SES, gender, family characteristics, school type, absenteeism and geographical variation, there is a small to moderate positive relationship between participation in a number of different leisure OSA and 7-year-olds' academic performance. Interestingly, variations among children from different SES groups were found in the extent to which attendance at certain OSA (e.g. after-school clubs) is associated with academic development between age 5 and 7: children from lower SES who attend such activities tend to progress more academically than children from intermediate and higher SES.

With a rapidly changing work environment due to increased migration and ease of travel, organisations today is challenged by a multicultural setting of individuals in employment. Additionally there is an increase in the number of highly educated employees working in the same teams as lesser educated individuals. The purpose of this paper is to research how the leadership is influenced by the cultural and educational diversity in a team. The study is a comparison study between two demographically similar teams in the same organisation. The difference between teams is that one team comprises of highly educated individuals classified under creative class based on Richard Florida's (2002) workforce classification. The other team comprises of individuals with lower education and are classified under service class. This research has found that the leadership is influenced in a different way when the level of education is included in the multicultural teams. Thus, besides culture, education also plays a big part in how the leadership is impacted.

Previous research implementing stratification on the propensity score has generally relied on using five strata, based on prior theoretical groundwork and minimal empirical evidence as to the suitability of quintiles to adequately reduce bias in all cases and across all sample sizes. This study investigates bias reduction across varying number of strata and sample sizes via a large-scale simulation to determine the adequacy of quintiles for bias reduction under all conditions. Sample sizes ranged from 100 to 50,000 and strata from 3 to 20. Both the percentage of bias reduction and the standardized selection bias were examined. The results show that while the particular covariates in the simulation met certain criteria with five strata that greater bias reduction could be achieved by increasing the number of strata, especially with larger sample sizes. Simulation code written in R is included.

This work approaches the topic of modeling the atmospheric boundary layer in four research projects, which are summarized below. i) The diurnal cycles of near-surface meteorological parameters over Antarctic sea ice in six widely used atmospheric reanalyses were validated against observations from Ice Station Weddell. The station drifted from February through May 1992 and provided the most extensive set of meteorological observations ever collected in the Antarctic sea ice zone. For the radiative and turbulent surface fluxes, both the amplitude and shape of the diurnal cycles varied considerably among different reanalyses. Near-surface temperature, specific humidity, and wind speed in the reanalyses all featured small diurnal ranges, which, in most cases, fell within the uncertainties of the observed cycle. A skill score approach revealed the superiority of the ERA-Interim reanalysis in reproducing the observed diurnal cycles. An explanation for the shortcomings in the reanalyses is their failure to capture the diurnal cycle in cloud cover fraction, which leads to errors in other quantities as well. Apart from the diurnal cycles, NCEP-CFSR gave the best error statistics. ii) The accuracy of prediction of stable atmospheric boundary layers depends on the parameterization of the surface layer which is usually derived from the Monin-Obukhov similarity theory. In this study, several surface-layer models in the format of velocity and potential temperature Deacon numbers were compared to observations from CASES-99, Cardington, and Halley datasets. The comparisons were hindered by a large amount of scatter within and among datasets. Tests utilizing R2 demonstrated that the Quasi-Normal Scale Elimination (QNSE) theory exhibits the best overall performance. Further proof of this was provided by 1D simulations with the Weather Research and Forecasting (WRF) model. iii) The increasing number of physics parameterization schemes adopted in numerical weather forecasting models has resulted in a proliferation of inter-comparison studies in recent years. Many of these studies concentrated on determining which parameterization yields results closest to observations rather than analyzing the reasons underlying the differences. In this work, the performance of two 1.5-order boundary layer parameterizations was studied, the QNSE and Mellor-Yamada-Janjić (MYJ) schemes, in the Weather Research and Forecasting (WRF) model. The objectives were to isolate the effect of stability functions on the near-surface values and vertical profiles of virtual temperature, mixing ratio and wind speed. The results demonstrate that the QNSE stability functions yield better error statistics for 2-m virtual temperature but higher up the errors related to QNSE are slightly larger for virtual temperature and mixing ratio. A surprising finding is the sensitivity of the model results to the choice of the turbulent Prandtl number for neutral stratification (Prt0): in the Monin-Obukhov similarity function for heat, the choice of Prt0 is sometimes more important than the functional form of the similarity function itself. There is a stability-related dependence to this sensitivity: with increasing near-surface stability, the relative importance of the functional form increases. In near-neutral conditions, QNSE exhibits too strong vertical mixing attributed to the applied turbulent kinetic energy subroutine and the stability functions including the effect of Prt0. iv) In recent years, many eddy-diffusivity mass flux (EDMF) planetary boundary layer (PBL) parameterizations have been introduced. Yet, most validations are based on idealized setups and/or single column models. To address this gap, this study focused on the effect the mass flux part has on the performance in the QNSE-EDMF PBL scheme in the WRF model by comparing the results to observations from the CASES-97 field campaign. In addition, two refined versions, one introducing the parameterized clouds to the WRF radiation scheme, and the second adding a different entrainment formulation, were evaluated. The introduction of mass flux reduced errors in the average moisture profile but virtual temperature and wind speed profiles did not change as much. The turbulent flux profiles for modeled virtual potential temperature were little affected, with consistent reasonable agreement with observations, if one allows for biases in the observed data and modeled surface fluxes. However, the water vapor flux divergences from QNSE tend to be more negative than observed, while including the mass flux part tends to make the divergences more positive, the latter at least partially due to deeper model PBLs resulting from excessive model surface virtual temperature fluxes. Further, both virtual potential temperature and water vapor flux profiles display spurious spikes attributed to the way the non-local and local terms interact in the model. The influence of the mass flux schemes extends to 60 – 100-km scale circulation features, which were greatly modified by both the inclusion of mass flux and the new entrainment formulation. Adding mass flux based clouds to the radiation calculation improved the time and space averaged modeled incoming shortwave flux. The choice of the representation for entrainment/detrainment often affected the results to the same extent as adding mass flux did.