Reducing losses of usable waste fiber from paper mills conserves valuable resources and has the capacity to produce considerable economic returns to the manufacturer. The purpose of this research effort was to evaluate the potential for the prevention of loss and/or recovery of usable waste fiber from paper machines within a fine paper mill. Further, a preliminary evaluation of fiber loss prevention strategies and fiber recovery technologies was conducted. The paper mill in question experienced losses of usable waste fiber to the sewer in amounts approaching, and sometimes exceeding 40 tons/day. An existing database of usable fiber test results was analyzed to determine patterns of fiber loss. Further testing showed that the most significant fiber losses resulted from centrifugal cleaner cones. These cones, designed to remove foreign material from stock, are one step in a series of mechanical cleaning devices in the stock preparation area of the paper mill. Cleaner cone systems on two of the paper machines were found to contribute most significantly to total fiber loss. Contrary to cleaner cone design, the dirt content of fiber rejects from cones experiencing excessive loss was very low. Cleaner cones on other machines operated normally. These rejects were extremely dirty and quantities of fiber were low. These results indicate poor operating efficiency of two of the cleaner cone systems in question. By adding cones where space is available, system capacity and efficiency will increase, fiber losses will decrease, and the dirt content of rejects will increase. This will result in substantial resource and financial savings to the paper mill. Technologies have been developed to recover usable fiber from paper mill sludge. However, prior to further investigation of the use of such innovations at this paper mill, efforts should focus on the reduction of fiber loss from point sources. / Master of Science

Text in Afrikaans / Real empowerment of school learners requires preparing them for the age of technology. This empowerment can be achieved by developing their higher-order thinking skills. This is clearly the intention of the proposed South African FET National Curriculum Statements Grades 10 to 12 (Schools). This research shows that one method of developing higher-order thinking skills is to adopt an integrated curriculum approach. The research is based on the assumption that an integrated curriculum approach will produce learners with a more integrated knowledge structure which will help them to solve problems requiring higher-order thinking skills. These assumptions are realistic because the empirical results of several comparative research studies show that an integrated curriculum helps to improve learners' ability to use higher-order thinking skills in solving nonroutine problems. The curriculum mentions four kinds of integration, namely integration across different subject areas, integration of mathematics with the real world, integration of algebraic and geometric concepts, and integration into and the use of dynamic geometry software in the learning and teaching of geometry. This research shows that from a psychological, pedagogical, mathematical and historical perspective, the theme conic sections can be used as an integrating factor in the new proposed FET mathematics curriculum. Conics are a powerful tool for making the new proposed curriculum more integrated. Conics can be used as an integrating factor in the FET band by means of mathematical exploration, visualisation, relating learners' experiences of various parts of mathematics to one another, relating mathematics to the rest of the learners' experiences and also applying conics to solve real-life problems. / Mathematical Sciences / D.Phil. (Wiskundeonderwys)

Text in Afrikaans / Real empowerment of school learners requires preparing them for the age of technology. This empowerment can be achieved by developing their higher-order thinking skills. This is clearly the intention of the proposed South African FET National Curriculum Statements Grades 10 to 12 (Schools). This research shows that one method of developing higher-order thinking skills is to adopt an integrated curriculum approach. The research is based on the assumption that an integrated curriculum approach will produce learners with a more integrated knowledge structure which will help them to solve problems requiring higher-order thinking skills. These assumptions are realistic because the empirical results of several comparative research studies show that an integrated curriculum helps to improve learners' ability to use higher-order thinking skills in solving nonroutine problems. The curriculum mentions four kinds of integration, namely integration across different subject areas, integration of mathematics with the real world, integration of algebraic and geometric concepts, and integration into and the use of dynamic geometry software in the learning and teaching of geometry. This research shows that from a psychological, pedagogical, mathematical and historical perspective, the theme conic sections can be used as an integrating factor in the new proposed FET mathematics curriculum. Conics are a powerful tool for making the new proposed curriculum more integrated. Conics can be used as an integrating factor in the FET band by means of mathematical exploration, visualisation, relating learners' experiences of various parts of mathematics to one another, relating mathematics to the rest of the learners' experiences and also applying conics to solve real-life problems. / Mathematical Sciences / D.Phil. (Wiskundeonderwys)

nÃo hà / Teorias em Economia Internacional sÃo desenvolvidas e testadas empiricamente, esta tese pretende contribuir com algumas delas. Inicialmente, dever-se-à abordar a chamada teoria de Cones de DiversificaÃÃo. Para tanto, o primeiro capÃtulo propÃe-se a separar em dois cones os estados do Brasil que apresentam semelhanÃas nas dotaÃÃes de fatores. Isto serà realizado atravÃs de um modelo economÃtrico SUR para dezoito indÃstrias de transformaÃÃo e duas amostras anuais, em 1997 e 2007. DiferenÃas salariais entre os cones tambÃm serÃo medidas com a mesma metodologia. A teoria de cones de diversificaÃÃo à revalidada uma vez que existe diferenciaÃÃo horizontal entre os produtos. O segundo capÃtulo elabora um modelo economÃtrico que delineia os efeitos da abertura comercial sobre os salÃrios dos trabalhadores pouco e altamente qualificados. Utilizou-se o arcabouÃo teÃrico da equaÃÃo minceriana para incorporar caracterÃsticas dos trabalhadores. Este trabalho objetiva analisar se, dada maior abertura comercial, bem como outros fatores relevantes, tais quais; experiÃncia, anos de estudo, intensidade tecnolÃgica do setor ao qual se emprega e quantidade de horas trabalhadas, houve aumento da renda do trabalhador industrial dos estados do Nordeste do Brasil para os anos da amostra. Adicionalmente, uma dummy à inserida no modelo com o objetivo de diferenciar os trabalhadores empregados nos setores de alta e baixa tecnologia. Encontram-se evidÃncias de que volume de exportaÃÃes, horas de trabalho, anos de estudo e experiÃncia impactaram positivamente no retorno do trabalhador. Maior abertura comercial apresenta grande influÃncia positiva sobre os salÃrios dos trabalhadores das indÃstrias analisadas. O Ãltimo capÃtulo apresenta um modelo gravitacional que serà aplicado a fim de estudar os determinantes do fluxo comercial entre o Estado do Cearà e os demais estados brasileiros. Este capÃtulo dirigiu sua atenÃÃo aos fatores que influenciam o fluxo de comÃrcio do Estado do Cearà para os demais estados do Brasil. Entre estes fatores, apontou-se inicialmente o espaÃo que separa os centros produtivos como um fator que atua influenciando negativamente o comÃrcio. Ainda, analisou-se o impacto das variÃveis Produto Interno Bruto e tamanho populacional, encontra-se que ambas exercem impacto positivo para o fluxo comercial. / Theories in International Trade are developed and empirically tested. This thesis aims to contribute with some of them. Initially, it will address the so-called Theory of Diversification Cones. Thus, the first chapter proposes to separate Brazilian states into two cones which have similarities in factor endowments. This will be accomplished through an SUR econometric model with eighteen manufacturing industries and two annual samples, in 1997 and 2007. Wage differences between the cones will also be measured with the same methodology. The Theory of Diversifiation Cones is renewed since there is horizontal differentiation between products. The second chapter develops an econometric model that outlines the effects of trade liberalization on wages of low and high-skilled workers. We used the theoretical framework of the Mincerian equation to incorporate characteristics of workers. This study aims to examine whether, given greater trade openness as well as other relevant factors, such that; experience, years of education, technological intensity of the sector to which it is used and the amount of hours worked, an increase in income of the industrial worker in the states of Northeast Brazil for the years of the sample. In addition, a dummy is inserted into the model with the aim to differentiate the workers employed in low and high-tech industries. There are evidences that export volume, hours, years of study and experience have a positive impact on the worker's return. Greater trade openness has a large positive influence on the wages of workers in industries analyzed. The final chapter presents a gravity model which will be applied for the purpose of studying the determinants of trade flows between the State of Cearà and other Brazilian states. This chapter turned its attention to the factors that influence the trade flow in the State of Cearà in other states of Brazil. Among these factors, the separation between the production centers was initially pointed as a factor that acts negatively influencing trade. The impact of the variables GDP and population size was also analyzed, and it was expected that both of them exert positive impact on trade flows.

Les neurones établissent entre eux de nombreux contacts synaptiques, et l'on estime qu’en moyenne un neurone peut avoir dix mille contacts avec les neurones de son voisinage. L'une des synapses les plus importantes et les plus étudiées, dont les dysfonctionnements conduisent à des pathologies du cerveau, est la synapse excitatrice glutamatergique. Dans l’hippocampe, les synapses excitatrices présentent une structure postsynaptique particulière, sous la forme d’un renflement de la dendrite appelé épine dendritique. Cette épine possède un domaine particulier, la densité postsynaptique, concentrant de nombreux récepteurs aux glutamates, des protéines d’adhésion ainsi que des protéines d’échafaudage faisant le lien avec les cascades moléculaires intracellulaires et le cytosquelette d’actine. La morphologie de l’épine dendritique ainsi que le nombre de récepteurs présents dans la PSD sont des éléments clés dans la transmission synaptique et les phénomènes de potentiation et de dépression à long terme (LTP & LTD). Lors de ma thèse, j’ai identifié Scribble1 comme une nouvelle protéine régulant le trafic des récepteurs NMDA. Scribble1 est surtout connue pour son implication dans des processus de polarité, division et migration cellulaire. En modulant le taux de Scribble1, j’ai montré que je pouvais affecter le nombre et la morphologie des épines des neurones hippocampaux, ainsi que la polymérisation de l’actine. Ensuite, j’ai démontré que Scribble1 interagissait directement avec les récepteurs NMDA et permettait leur recyclage à la membrane. Enfin, chez le neurone immature, Scribble1 est impliqué dans la migration du cône axonal. Chez un animal mutant, qui n’exprime que 50% de la protéine (circletail) les performances mnésiques et sociales de l’animal sont perturbées, validant le rôle de la protéine au niveau du système nerveux. / One of the most studied and more important synapse is the glutamatergic excitatory synapse, which dysfunctions lead to brain pathologies. In the hippocampus, the most represented synapses are glutamatergic synapses using glutamate as neurotransmitter. Postsynaptic structures, such as dendritic spines, concentrate many glutamate receptors, adhesion proteins and scaffold proteins bridging receptors to molecular cascades and intracellular actin cytoskeleton. The morphology of the dendritic spine and the number of glutamate receptors at the surface of the spine are key-elements in synaptic transmission, such as of long-term potentiation (LTP). In this study, I identify Scribble1 as an important regulator of NMDA receptors trafficking. Scribble1 is well known for its roles in cell polarity, division and migration processes. First, I show that Scribble1 gain- and loss-of-function affect the number and morphology of spines, as well as the actin polymerization. Next, I showed that Scribble1 interacts directly with the NMDA receptor and stimulates its recycling to the membrane. Finally, in immature neuron, Scribble1 is involved in axon growth cone migration. In a Scribble1 mutant animal model, circletail, we observed disruption of synaptic transmission and memory and social performance defects, compatible with a role of the protein in central nervous system function.

Milhares de cones siliciosos foram mapeados próximo de Anhembi, estado de São Paulo, e sugere tratar-se do mais importante registro geológico resultante de uma intensa atividade hidrotermal ocorrida no Período Permiano. Essa ocorrência é única no mundo devido à grande quantidade de cones silicosos e sua distribuição em pequena área. Na realidade, esses cones siliciosos foram classificados como geiseritos, registrando a existência de gêiseres no final do Permiano. Os geiseritos encontrados em Anhembi desenvolveram-se simultaneamente à sedimentação do siltitos e arenitos da Formação Teresina. Os cones encontram-se bem preservados, pois estão sendo exumados pela erosão moderna. No entanto, há indícios da presença de corpos ainda soterrados nos sedimentos da Formação Teresina. A fim de identifica-los foi usado os métodos geofísicos do georradar e da resistividade para mapeamento de subsuperfície. Os resultados mostram que há corpos enterrados até seis metros de profundidade nas localidades em que os geiseritos encontram-se exumados. Portanto, o campo de ocorrência desses cones é maior que o inicialmente conhecido pelas evidências em superfície. / Thousands of siliceous mounds have been found near to Anhembi, state of São Paulo, which are supposed to be the geological record of a huge hydrothermal activity of Late Permian. This occurrence is unique in the world due to the number of siliceous mounds and its distribution in a small area. Actually, these siliceous mounds are nominated geyserites since they record the existence of geysers at Late Permian. Geyserites found in Anhembi developed simultaneously with sedimentation of siltstones and sandstones of the Teresina Formation. These geyserites are being exhumed by modern erosion and this is the reason they are well preserved. However, it´s presumed there are a lot of buried geyserites still within sediments of the Teresina Formation. In order to identify them we used GPR - ground penetrating radar - and resistivity to subsurface mapping. Results show buried geyserites four meters below the ground surface where exhumed geyserites are found. Therefore, this geyserite field is much bigger than it is supposed to be just seeing on the ground surface.

Milhares de cones siliciosos foram mapeados próximo de Anhembi, estado de São Paulo, e sugere tratar-se do mais importante registro geológico resultante de uma intensa atividade hidrotermal ocorrida no Período Permiano. Essa ocorrência é única no mundo devido à grande quantidade de cones silicosos e sua distribuição em pequena área. Na realidade, esses cones siliciosos foram classificados como geiseritos, registrando a existência de gêiseres no final do Permiano. Os geiseritos encontrados em Anhembi desenvolveram-se simultaneamente à sedimentação do siltitos e arenitos da Formação Teresina. Os cones encontram-se bem preservados, pois estão sendo exumados pela erosão moderna. No entanto, há indícios da presença de corpos ainda soterrados nos sedimentos da Formação Teresina. A fim de identifica-los foi usado os métodos geofísicos do georradar e da resistividade para mapeamento de subsuperfície. Os resultados mostram que há corpos enterrados até seis metros de profundidade nas localidades em que os geiseritos encontram-se exumados. Portanto, o campo de ocorrência desses cones é maior que o inicialmente conhecido pelas evidências em superfície. / Thousands of siliceous mounds have been found near to Anhembi, state of São Paulo, which are supposed to be the geological record of a huge hydrothermal activity of Late Permian. This occurrence is unique in the world due to the number of siliceous mounds and its distribution in a small area. Actually, these siliceous mounds are nominated geyserites since they record the existence of geysers at Late Permian. Geyserites found in Anhembi developed simultaneously with sedimentation of siltstones and sandstones of the Teresina Formation. These geyserites are being exhumed by modern erosion and this is the reason they are well preserved. However, it´s presumed there are a lot of buried geyserites still within sediments of the Teresina Formation. In order to identify them we used GPR - ground penetrating radar - and resistivity to subsurface mapping. Results show buried geyserites four meters below the ground surface where exhumed geyserites are found. Therefore, this geyserite field is much bigger than it is supposed to be just seeing on the ground surface.

As we know the most popular inference methods for order restricted model are likelihood inference. In such models, the Maximum Likelihood Estimation (MLE) and Likelihood Ratio Testing (LRT) appear some suspect behaviour and unsatisfactory. In this thesis, I review the articles that focused in the behaviour of the Likelihood methods on Order restricted models. For those situations, an alternative method is preferred. However, likelihood inference is satisfactory for simple order cone restriction. But it is unsatisfactory when the restrictions are of the tree order, umbrella order, star-shaped and stochastic order types.

Magistro darbe tiriama mikrobangų poveikis įvairių rūšių medžiams. Darbo objektas – Paprastosios pušies ( Pinus sylvestris L. ) sėklų gemalai, paprastosios eglės (Picea abies (L.) Karst.) gemalai ir augimo kūgeliai, paprastojo uosio ( Fraxinus excelsior L.) gemalai, karpotojo beržo (Betula pendula L.) žiedadulkės. Darbo tikslas – Įvertinti mikrobangų poveikį skirtingų medžių rūšių subrendusių gemalų ir žiedadulkių gyvybingumui. Darbo metodika – mikrobangomis paveikiami subrendę gemalai, augimo kūgeliai žiedadulkės ir distiliuotas vanduo. Įvertinama mikrobangų įtaka gemalų, augimo kūgelių, žiedadulkių gyvybingumui. Rezultatai – Mikrobangos 600 W rėžime neigiamai veikia eglės, pušies ir uosio subrendusių gemalų gyvybingumą. Iš tirtų 480 subrendusių gemalų gyvybingi liko 183 eksplantai ( 38,1 %). Paveikus mikrobangomis beržo žiedadulkes, bangos stabdė žiedadulkių vystymąsi. Paveiktas mikrobangomis distiliuotas vanduo teigiamai veikė karpotojo beržo žiedadulkes, skatindamas žiedadulkių dygimą. Paprastosios eglės augimo kūgeliai paveikti mikrobangomis žuvo visuose eksperimento variantuose, išskyrus nepaveikti mikrobangomis augimo kūgeliai. / In the postgraduate thesis studied effect of microwaves on different trees species. Study object. Mature germ of Common Scots pine (Pinus sylvestris L.), Common Ash (Fraxinus excelsior L.), mature germ and growth cones of Norway spruce (Picea abies (L.) Karst.), pollen of Silver Birch (Betula pendula L.). Purpose of the study – to estimate the effect of microwaves on different trees species of mature germ and pollen viability. Study methods. Affected by microwaves mature germs, growth cones, pollen and distilled water. Rated microwave power of germs, growth cones and pollen viability. Results. Microwave 600 W mode affects spruce, pine and ash mature germs viability. Of investigated 480 mature germs remained viable explants 183 (38.1%). Birch pollen exposed of microwave, the waves slowed the development of pollen. Affected by microwave distilled water acted positively Silver birch pollen and stimulating germination. Growth cones of Norway spruce were killed of microwave affect all versions on the experiment, except do not affect the growth cone of microwaves.

Mémoire (M.Ress.Renouv.)-- Université du Québec à Chicoutimi, 1994. / Document électronique également accessible en format PDF. CaQCU