Spelling suggestions: "subject:"cross""
311 |
Captura e alocação de carbono em Pinus taeda e Pinus caribaea var. hondurensis sob manejos hídricos e nutricionais distintos / Carbon sequestration and allocation in Pinus taeda and Pinus caribaea var. hondurensis under distinct hidric and nutritional regimesIsabel Deliberali 25 January 2016 (has links)
O gênero Pinus ocupa no Brasil uma área plantada de 1,59 milhão de hectares e tem uma ampla faixa de produtividade florestal (18 a 45 m3 ha-1 ano-1), em função das espécies utilizadas, das limitações edáficas, dos tipos de clima, melhoramento genético e, e alguns casos, pela ocorrência de pragas e doenças. Apesar do conhecimento de que o aumento da disponibilidade de recursos naturais (luz, água e nutrientes) eleva a produção de madeira, faz-se necessário compreender como estes recursos influenciam os processos de captura (produção primária bruta ou GPP) e alocação de carbono (C) para os diferentes compartimentos da floresta (raiz, lenho, galhos e folhas). Além disso, o grau de controle genético é de grande importância nesses processos e também deve ser analisado. Assim, este projeto objetivou quantificar as taxas de captura e alocação de carbono em uma espécie de Pinus tropical (P. caribaea var. hondurensis) e em uma subtropical (P. taeda), dos 6,5 aos 8,5 anos de idade, em parcelas controle (sem fertilização e sem irrigação) e parcelas fertilizadas e irrigadas. O experimento está localizado no município de Itatinga - SP e se utilizou o método do balanço de carbono para estimar a produtividade primária líquida da parte aérea (ANPP), o fluxo de carbono para o solo (TBCF), produtividade primária bruta (GPP) e produtividade líquida do ecossistema (NEP). Ao final do estudo, a biomassa do tronco foi 75% superior no P. caribaea var. hondurensis (126 Mg ha-1) do que no P. taeda (72 Mg ha-1), sendo que em ambas as espécies houveram ganhos significativos com a fertilização e irrigação. O primeiro ano avaliado foi mais seco do que o segundo (1195 contra 1487 mm), resultando em diferenças nos fluxos calculados. A produção de tronco do P. caribaea var. hondurensis variou de 722 a 1569 gC m-2 ano-1, enquanto do P. taeda foi de 221 a 452 gC m-2 ano-1. A espécie subtropical obteve os maiores valores de TBCF, variando de 1150 a 2197 gC m-2 ano-1, e para as duas espécies se encontrou relação do TBCF com a ANPP e GPP. Assim, encontrou-se que a maior produtividade da espécie tropical é resultado de seu maior GPP (4964 contra 3744 gC m-2 ano-1 no P. taeda), maior partição de carbono para incremento de tronco (22% contra 9% no P. taeda) e menor partição para TBCF (23% contra 45% no P. taeda). Já a fertilização e irrigação não mudaram a partição da GPP para a ANPP e TBCF comparado ao tratamento controle, e o ganho em produção de madeira foi explicado apenas pelo aumento na GPP (11%). A NEP para ambas as espécies foi positiva, mostrando que essas espécies estão atuando como drenos de carbono. Assim, o conhecimento de como a captura e alocação de C é afetada pela espécie, água e nutrição terá aplicação sobre o manejo florestal, além de propiciar valores de fluxos essenciais para a calibração de modelos ecofisiológicos de produção, ainda inexistentes para essas espécies no Brasil. / The genus Pinus in Brazil has a planted area of 1.59 million hectares and it has a wide range of forest productivity (18-45 m3 ha-1 yr-1) depending on the species, edaphic limitations, climate, breeding and, in some cases, the occurrence of pests and diseases. Despite knowing that the increased resources availability (light, water and nutrients) improves the production of wood, it is necessary to understand how these features influence the uptake processes (gross primary production or GPP) and carbon allocation (C) on the different forest compartments (root, bole, branch and leaf). Furthermore, the degree of genetic control is rather important in these processes and should also be analyzed. Thus, this project aimed to quantify carbon sequestration and allocation rates in a tropical pine (P. caribaea var. hondurensis) and a subtropical one (P. taeda), from ages 6.5 to 8.5 years old, in control plots (no fertilization and no irrigation) and fertilized and irrigated plots. The experimental site is located in Itatinga- SP and the carbon balance approach was used to estimate the above ground net primary production (ANPP), total belowground carbon flux (TBCF), gross primary production (GPP) and net ecosystem production (NEP). At the end of the study, the bole biomass was 75% higher in the P. caribaea var. hondurensis (126 Mg ha-1) than in P. taeda (72 Mg ha-1), and in both species there were substantial improvements with fertilization and irrigation. The first year evaluated was drier than the second (from 1195 to 1487 mm), resulting in differences in the calculated fluxes. The P. caribaea var. hondurensis bole production ranged from 722 to 1569 gC m-2 yr- 1, while the P. taeda showed values from 221 to 452 gC m-2 yr-1. The subtropical specie obtained the largest values of TBCF (from 1150 to 2197 gC m-2 yr-1), and on both species there was relationship between TBCF and ANPP and GPP.Thus, the higher productivity of tropical specie is a result of higher GPP (4964 versus 3744 gC m-2 yr-1 in the P. taeda), increased carbon partitioning to bole increment (22% versus 9% in the P. taeda) and smaller partitioning for TBCF (23% versus 45% in the P. taeda). Fertilization and irrigation have not changed the partitioning from GPP to ANPP and TBCF compared to the control plots, and increase in the production of wood it has been explained only by increased GPP (11%). The NEP for both species was positive, showing that these species are acting as carbon sinks. Therefore, the knowledge of how the carbon sequestration and allocation is affected by the species, water and nutrition will have application on forest management, besides providing values of essential fluxes for calibration of ecophysiological production models, still non-existent for these species in Brazil.
|
312 |
Fontes nitrogenadas e teor de proteína bruta em dietas com cana de açúcar para vacas em lactação: balanço de nitrogênio e análise econômica / Nitrogen sources and level of crude protein in diets with sugarcane for lactating dairy cows: nitrogen balance and economical evaluationCamila Silano 14 February 2014 (has links)
O estudo consistiu de dois experimentos com o objetivo de avaliar o efeito metabólico, custos e viabilidade econômica de dietas com diferentes fontes nitrogenadas e teores proteicos. No primeiro experimento avaliou-se o efeito de dois teores de proteína bruta (PB) (130 e 148g/kg de MS) e duas fontes nitrogenadas (farelo de algodão 38 e grão de soja cru integral) na dieta de vacas leiteiras com cana de açúcar como volumoso, sobre as frações nitrogenadas do leite, balanço de nitrogênio e perfil metabólico. Foram utilizadas 12 vacas da raça Holandesa com 155 (±65) dias em lactação, agrupadas em três quadrados latinos 4x4 contemporâneos, com período experimental de 21 dias, sendo 14 dias para adaptação às dietas e os sete últimos para a realização das coletas. As vacas foram alojadas em baias individuais e alimentadas ad libitum. As amostras de leite para análise do balanço nitrogenado e frações nitrogenadas foram coletadas no 15° dia de cada período. O consumo e balanço de nitrogênio foram maiores para vacas alimentadas com dietas com 148 g PB/kg de MS. Por outro lado, vacas alimentadas com dietas contendo farelo de algodão apresentaram maior excreção de nitrogênio no leite do que vacas alimentadas com grão de soja cru integral. A relação entre caseína e proteína verdadeira no leite foi maior em vacas alimentadas com grão de soja cru integral. Houve interação entre fonte nitrogenada e teor de PB da dieta sobre as concentrações de nitrogênio ureico no leite (NUL) e nitrogênio não proteico (NNP). A concentração de NUL foi maior em vacas alimentadas com farelo de algodão e com maior teor de PB, em contrapartida houve menor excreção de NUL em vacas alimentadas com grão de soja com maior teor proteico. Não houve efeito das dietas sobre os teores de proteína do leite, nitrogênio não caseinoso (NNC), caseína e proteína do soro. Conclui-se que o uso de dietas com 130g de PB/Kg na MS não altera o balanço de nitrogênio e de composição do leite de vacas leiteiras em comparação com teores de 148g/Kg de PB na MS, e resultam em menor excreção de nitrogênio no ambiente. No segundo experimento foram calculados os custos e margens totais de dietas com cinco fontes nitrogenadas principais (ureia, farelo de soja, farelo de algodão, grão de soja cru integral e farelo de glúten de milho) e cinco teores proteicos (130, 145, 148, 157 e 160 g/kg de MS) com cana de açúcar como volumoso para vacas em lactação. Os dados foram provenientes de três estudos conduzidos com a finalidade de coleta de dados produtivos e respostas metabólicas. A análise econômica foi realizada com base nos preços históricos deflacionados (corrigidos do efeito da inflação) praticados durante o período 2002 a 2012, e no cálculo dos custos de alimentação, em função do consumo de alimento, da produção de leite e do teor de proteína bruta no leite. Dietas com cana de açúcar com teor proteico de 14,5% com ureia como fonte nitrogenada principal apresentaram a maior margem bruta (diferença entre a receita da venda do leite e do custo da dieta) com valor médio anual de R$1,85.vaca-1.dia-1. A dieta com 14,8% de PB com grão de soja cru integral apresentou a menor margem bruta de R$ 2,16.vaca-1.dia-1. / The study consisted of two experiments to evaluate the N balance and economical analysis of diets with different nitrogen sources and crude protein levels. On the first experiment it was evaluated the effect of two crude protein (CP) levels (130 e 148 g/kg DM) and two nitrogen sources (cottonseed meal 38% and whole raw soybean) in diets of dairy cows using sugar cane as forage on nitrogen in milk, nitrogen balance and metabolic parameters. Twelve Holstein cows with 155 (±65) days in lactation were distributed into three contemporary 4x4 Latin squares, with experimental period of 21 days, 14 days for diet adaptation and the remaining seven days for sampling. The cows were housed in individual pens and fed ad libitum. Milk samples for nitrogen balance and milk nitrogen fractions analysis were collected on the 15th day of each experimental period. Nitrogen intake and nitrogen balance were higher for the cows fed diets with 148 g CP/kg DM. However cows fed diets with cottonseed meal had higher nitrogen excretion in milk than cows fed diets with whole raw soybean. The casein: true milk protein ratio was higher in cows fed diets with whole raw soybean. There was interaction between the nitrogen source and the diet CP content on the milk urea nitrogen and non-protein nitrogen. Milk urea nitrogen was higher in cows fed diets with cottonseed meal and higher CP concentrations, however lower milk urea nitrogen was observed in cows fed diets with whole raw soybean and higher CP concentration. The concentration of crude protein, noncasein protein, casein and whey protein in milk did not differ between diets. In conclusion the use of low concentrations of protein (130g/Kg in MS) does not affect the performance of dairy cows and provides lower excretion of nitrogen in the environment. On the second experiment, the costs and the gross margin were calculated for diets formulated with five nitrogen sources (urea, soybean meal, cottonseed meal, whole raw soybean and corn gluten meal) and five protein levels (130, 145, 148, 157 e 160 g/kg DM) using sugar cane as forage. Performance data were obtained from three experiments conducted previously. Economical analysis were performed based on historical prices adjusted for the effect of inflation during the period between 2002 and 2012 and based on the feed costs, cow intake, milk prodution and milk protein levels. The higher gross margin (difference between the income from milk sale and diet costs) were obtained for 145 g/kg of CP in DM diets and urea as main nitrogen source, with mean of R$1,85.vaca-1.dia-1. The lower gross margin were observed in the 148 g/kg of CP in DM diet and whole raw soybean as nitrogen source, with mean of R$ 2,16.vaca-1.dia-1.
|
313 |
Indicadores municipais para o monitoramento da evolução econômica e social / Municipal indicators for monitoring the economic and social evolutionHilda Pena Porto de Oliveira 08 November 2010 (has links)
O objetivo do trabalho é pesquisar indicadores que possibilitem aos usuários interessados, acompanhar o desempenho econômico e social dos municípios do Estado de São Paulo. Comparar cada indicador em relação ao seu objetivo, formulação, abrangência, periodicidade, responsabilidade, limitação e disponibilidade. Posteriormente, selecionar os indicadores que se mostraram mais apropriados para mensurar a desigualdade sócio-econômica entre os municípios. Parte dos dados obtidos serão espacializados com a geração de mapas temáticos utilizando o aplicativo desenvolvido pelo DATASUS, do Ministério da Saúde. A geração e utilização de Indicadores Sociais e Econômicos espacializáveis, além de possibilitar o conhecimento das condições de vida de uma população, é uma ferramenta fundamental para orientar as políticas públicas no sentido de promover o bem-estar social dos munícipes. / The objective of this research is to search for indicators to enable interested users to monitor the economic and social performance of the São Paulo States Municipalities. Comparing each indicator in relation to its objective, formulation, comprehensiveness, timeliness, responsibility, control and availability. Afterwards, to select the indicators that were more appropriate to measure the socioeconomic inequality among these municipalities. Part of the obtained data will be spatialized with the generation of thematic maps using an application developed by DATASUS, the Ministry of Health. The generation and use of Social and Economic Indicators, in addition to providing the knowledge of populations living conditions, is a suitable tool to guide public policies to promote the citizens welfare.
|
314 |
Ausência de pré-natal e gravidez na adolescência : um estudo ecológico no Estado de São Paulo / Lack of prenatal care and teenage pregnancy : ecological study in São PauloGuerra, Maria Silvia Bergo, 1983- 25 August 2018 (has links)
Orientador: Antonio Carlos Pereira / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-25T23:32:42Z (GMT). No. of bitstreams: 1
Guerra_MariaSilviaBergo_M.pdf: 875000 bytes, checksum: f66d397442562d93e5033ed703495ebe (MD5)
Previous issue date: 2014 / Resumo: O pré-natal inadequado e a gestação durante a adolescência são alguns dos fatores que, conhecidamente, interferem na saúde materno-infantil. Modelos conceituais defendem as condições contextuais e os modelos de atenção em saúde como determinantes nesse processo. Essa dissertação produziu dois artigos, que foram divididos capítulos e que tiveram como objetivos verificar como as variáveis contextuais e do modelo de atenção em saúde interferem: a.) na ausência de pré-natal (capítulo 1); e, b.) na gestação durante a adolescência (capítulo 2). Através de um estudo ecológico, em todos os 645 municípios do Estado de São Paulo, durante os anos de 1998 a 2008, pesquisou-se a tendência da ausência de pré-natal e da gravidez na adolescência, bem como possíveis variáveis contextuais e de modelo de atenção podem impactá-las. Para avaliar a ausência de pré natal, a variável dependente foi o coeficiente de nascidos vivos de mães que não fizeram pré-natal (zero consultas); e para avaliar a gestação na adolescência, utilizou-se como variável dependente o coeficiente de nascidos vivos de mães adolescentes (menores de 20 anos). Foram consideradas como características contextuais o PIB per capta e o número de habitantes, por município. Para avaliar o modelo de atenção, foram consideradas a proporção de equipes de Saúde da Família e de Agentes Comunitários de Saúde implantados, por município. Verificou-se que as características contextuais e do modelo de atenção foram significativas, ou seja, o PIB per capta (p<0,0001) e o número de habitantes de cada município (p<0,05) e proporção de equipes de Saúde da Família implantadas (p<0,05) interferiram na variação da ausência de pré-natal; e que, PIB per capta e proporção de Agentes Comunitários de Saúde influenciaram na variação de mães adolescentes(p<0,0001 e p<0,0013, respectivamente). A ausência de pré-natal e a gravidez na adolescência demonstraram tendência de queda, no Estado de São Paulo, no período estudado, influenciada principalmente pelo PIB per capta e pelo modelo de atenção em saúde / Abstract: Inadequate prenatal care and pregnancy during adolescence are some of the factors, known to interfere in maternal and child health. Conceptual models advocate the contextual conditions and models of health care as determinants in this process. This thesis has produced two articles, which were divided chapters and had as aim to verify how the contextual and the health care model variables affect: a) the absence of prenatal care (Chapter 1);. and b.) in pregnancy during adolescence (Chapter 2). Through an ecological study, in all 645 counties of the State of São Paulo, during the years 1998 to 2008, researched the trend of lack of prenatal care and teen pregnancy, as well as possible contextual variables and model attention may have an impact on them. To assess the absence of prenatal, the dependent variable was the ratio of live births to mothers who did not receive prenatal care (consultations zero); and to assess adolescent pregnancy, was used as the dependent variable coefficient of live births to teenage mothers (under 20 years). Contextual characteristics were considered as GDP per capita and the number of inhabitants per municipality. To evaluate the model of care were considered the proportion of Family Health Teams and Community Health Agents deployed, by municipality. It was found that the contextual features and the care model were significant, ie, GDP per capita (p <0.0001) and the number of inhabitants in each municipality (p <0.05) and proportion of Health teams deployed family (p <0.05) variation interfered in the absence of prenatal care; and that GDP per capita and proportion of community health workers influenced the variation in teenage mothers (p <0.0001 and p <0.0013, respectively). The lack of prenatal care and teen pregnancy have shown a declining trend in the state of São Paulo in the period studied, mainly influenced by per capita GDP and the model of health care / Mestrado / Odontologia em Saude Coletiva / Mestra em Odontologia em Saúde Coletiva
|
315 |
Localisation d'Anderson avec des atomes froids : dynamique dans le désordre et perspectives avec des modèles chaotiques / Anderson localization with cold atoms : dynamics in disorder and prospects from chaosPrat, Tony 25 September 2017 (has links)
Dans cette thèse, nous étudions théoriquement plusieurs effets liés à la localisation d'Anderson, dans le contexte des atomes froids. Dans les systèmes d'atomes froids, le désordre est généralement créé à l'aide d'une figure de tavelure optique. Dans la première partie de la thèse, nous discutons des spécificités de ces potentiels optiques, et nous nous intéressons en particulier aux propriétés spectrales. Les expériences usant de l'interaction lumière-matière offrent d'intéressantes possibilités. Dans ce cadre, nous considérons dans une deuxième partie de la thèse l'étalement d'un paquet d'ondes atomique, initialement lancé avec une vitesse non nulle dans un potentiel désordonné. Nous trouvons qu'après un mouvement balistique, le centre de masse du paquet subit une rétro-réflection et retourne lentement à sa position initialle, se comportant comme un boomerang. Nous introduisons ensuite les interactions inter-atomiques dans une troisième partie. Nous considèrons des gaz dilués de bosons condensés, et traitons les interactions au niveau champ moyen. Plusieurs situations sont étudiées numériquement, en particulier le boomerang quantique, et l'étalement dynamique -- à la fois en impulsion et en énergie -- d'ondes de matière préparées en ondes planes. Dans la dernière partie de la thèse, nous montrons que des modèles chaotiques offrent des perspectives intéressantes pour l'étude de la localisation d'Anderson. D'une part, nous présentons des éléments probants en faveur d'un kick rotor sans spin dans l'ensemble symplectique. D'autre part, le réexamen de modèles communément étudiés de kick rotors quasi-périodiques révèle des résultats intrigants. / This thesis theoretically investigates several effects related to Anderson localization, focusing on the context of disordered and chaotic cold-atomic systems. In cold-atomic systems, optical speckle patterns are often used to create the disorder. The resulting potentials felt by the atoms differ from Gaussian random potentials, commonly assumed in the description of condensed-matter systems. In the first part of the thesis, we discuss their specificities, with an emphasis on the spectral properties. Atom-optics experiments offer interesting possibilities, such as the possibility to directly probe the atoms inside the disordered potential. In view of these possibilities, we consider in the second part of the thesis the spreading of matter wave packets initially launched with a non-zero velocity. We find that after an initial ballistic motion, the packet center-of-mass experiences a retroreflection and slowly returns to its initial position, mimicking a boomerang. Atom-atom interactions are then introduced in a third part. We consider dilute condensed bosonic gases, and treat the interactions at the mean-field (Gross-Pitaevskii) level. Various situations are studied numerically, in particular the quantum boomerang scenario, and the dynamical spreading both in momentum and energy of matter waves prepared as plane waves. In the last part, we show that chaotic models offer interesting prospects for the study of Anderson localization. On the one hand, we present strong evidences in favor of a spinless kicked rotor in the sympletic ensemble. On the other hand, a second look at a commonly studied quasi-periodically modulated kicked rotor reveals intriguing results.
|
316 |
Optical studies of polar InGaN/GaN quantum well structuresBlenkhorn, William Eric January 2016 (has links)
In this thesis, I will present and discuss research performed on InGaN/GaN multiple quantum well (QW) structures. The results of which were taken using photoluminescence (PL) spectroscopy and PL time decay spectroscopy. In the first two experimental chapters, I report on the effects of QW growth methodology on the optical properties of c-plane InGaN/GaN QWs. I compare structures grown using the single temperature (1T), quasi-two temperature (Q2T), temperature bounced (T-bounced) and two temperature (2T) QW growth methodologies. The T-bounced and 2T structures are observed to have gross well width fluctuations (GWWF), where the QW width varies from 0 to 100 % created when the QWs are exposed to a temperature ramp. Whereas, the 1T and Q2T structures have continuous QWs with only one or two monolayer well width fluctuations. The structures with GWWFs are observed to have a larger room temperature internal quantum efficiency (RT-IQE) at low excitation conditions i.e. below efficiency droop compared to those without. The larger RT-IQE is ascribed to several factors which include an increased radiative recombination rate, increased thermal activation energy of non-radiative recombination and reduced defect density of the QWs. The effect of barrier growth temperature is also investigated. No clear trend is observed between barrier growth temperature and RT-IQE.In the last experimental chapter I report on studies of carrier localisation in InGaN/GaN QWs using resonant PL spectroscopy. The effect of carrier localisation on the independently localised electrons and holes are investigated and the resonant PL spectrum is studied in detail. The InGaN/GaN QW structure is observed to exhibit an effective mobility edge at 12 K where delocalised carriers are created above a particular excitation energy. The emission from the resonantly excited localised states which are accompanied by the emission of a longitudinal optical phonon (resonant LO feature) is investigated as a function of temperature and excitation energy. The integrated PL intensity of the resonant LO feature is observed to quench rapidly with temperature up to around 45 K, independent of excitation energy. The integrated PL intensity of the resonant LO feature is fitted to an Arrhenius model and a thermal activation energy of ∼ 1(±1) meV is extracted. This activation energy is speculated to be consistent with the localisation energy of electrons.
|
317 |
NÁRODOHODSPODÁŘSKÉ DOPADY INSTITUCIONÁLNÍ RESTRUKTURALIZACE APLIKOVANÉHO ČESKÉHO ZEMĚDĚLSKÉHO VÝZKUMU / Institutional restructuring Czech Agricultural ResearchŠlajs, Jan January 2017 (has links)
This dissertation entitled The Economical Implications of Institutional Restructuring of Applied Czech Agricultural Research solves the issue of effectiveness of applied national agrarian research, which is financed from public funds. The purpose of this thesis is to describe the current basis of applied agricultural research funded by the governance, respectively those scientific institutions that are eligible for an annual institutional grant to long-term development. Describe their focus and structure of results. Another purpose is to look for possible reserves in the system and to propose the restructuring of national applied agricultural research in organizations established by the Ministry of Agriculture of the Czech Republic. I have focused on comparing the outputs of scientific institutions in the periods of science and research support programs since 2007. In the data evaluated by the research institutions, I have been using bases in the last five years. From the point of view of the effectiveness of applied agricultural research, I am using data from 1989, respectively 2003. I solved the chosen topic of the dissertation by progressive steps. First, I evaluated the individual research institutions in terms of their outputs within the announced programs of support for science and research. I was looking for the argument that there is a substitute in the form of a private research organization in the current system of public research institutions. Which I didn´t find. State established applied agricultural research is unique in its content. For a comprehensive view, I have analysed the structure and types of research results achieved in the announced support programs. Problematics was solved mainly by comparison analysis based on literature, data and their aggregated results. The economic and social policy impacts are processed on the performance of the agriculture - food industry complex in terms of gross added value, socio-demographic data about workers in the field and complex. The dissertation proposes a new organization structure of applied agricultural research established by the state. A system of the central agriculture research organization is designed on the base of the current geographical distribution on the territory of the capital city Prague and Brno. The solution provides a more complex use of the existing unused potential of agriculture public research organizations. At the same time the standard elements of modern management are applied. Research has shown that the current system of funding science and research, which prefer quantity rather than output quality, is a major failure. At the same time, the work has shown that there is a way-out from the current fragmented system of the organization of applied agricultural research while preserving its unique possibilities. The results of this work enable, in the case of political will, the realization of greater efficiency of applied agricultural research established by the state in the Czech Republic.
|
318 |
The interrelationships between foreign direct investment and economic growth in AfricaBolani, Lindelwa Mandisa January 2015 (has links)
There has been a long search for the keys to development and economic growth in Africa. This study investigates the relationship between FDI and economic growth over the period 2000-2012 using data from 48 African countries. On the aggregate regional level FDI and economic growth were found to be positively correlated during this period. Using panel data econometric techniques and the Panel Granger Causality test, results revealed that a bi-directional causality relationship existed between FDI and GDP. Thus, the results suggest that GDP is a requirement for increased investment, and at the same time is the result of increased foreign investment. Thus, the conclusion is that African policy makers are justified in increasing their attempts to create an attractive business environment for foreign investors, as it is beneficial for economic growth.
|
319 |
Interférométrie atomique avec un condensat de Bose-Eintein : effet des interactions internes / Atom interferometry with a Bose-Einstein condensate : effect of internal interactionsJannin, Raphaël 08 October 2015 (has links)
Le travail réalisé dans le cadre de cette thèse s'articule en deux volets. Le premier porte sur l'étude de l'effet des interactions entre atomes au sein d'un interféromètre atomique, dont la source est un condensat de Bose-Eintein. Nous présentons un modèle analytiquepermettant d'obtenir des expressions simples pour le déphasage induit par celles-ci. Ce modèle est comparé à des simulations numériques résolvant les équations de Gross-Pitaevskii couplées, et présente un excellent accord. Le second concerne la conception et la construction d'un nouveau dispositif expérimental visant à obtenir un condensat de Bose-Einteindans le but de réaliser des mesures de haute précision par interférométrie atomique. / The work performed during this thesis comprises two orientations. The first one is the study of the effect of interactions between atoms in an atom interferometer which source of atoms is a Bose-Einstein condensate. We present an analytical model allowing to obtain simple expressions for the phase shift induced by them. This model is compared to numerical simulations solving the coupled Gross-Pitaevskii equations and presents a good agreement. The second one is the design and construction of a new experimental set-up for the production of a Bose-Einstein condensate to perform high precision measurements with the use of atom interferometry.
|
320 |
Odhad kapitálových služeb v České republice / Estimate of Capital Services in the Czech RepublicHudrlíková, Lenka January 2009 (has links)
This diploma paper discusses the importance of implementation of capital into the system national accounts. The purpose of this work is an estimation of capital services for real data of the Czech Republic. Conducted its own calculation is first such comprehensive estimate of the capital services, which was made. The diploma paper is divided into three parts. In the first part there is a explaination of concept of capital services and the methods of estimation and possible ways of calculating the necessary data. In the second part there is already done my own calculations of estimate of capital services used the methodology recommended by the OECD, but subject to certain adjustments, which are better suited to national conditions. Due to the volume of data all the calculations are listed in the Annex. In the text work is illustrative example of one sector of economic activity and the economy as a whole. The last section deals with experimental estimates of impact of capital services on macroeconomic aggregates, particularly gross domestic product. Other possibilities obtained an estimate of capital services, it is possible to estimate multi-factor productivity. Capital services can be used to express the input of capital.
|
Page generated in 0.0848 seconds