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Réduction de la dimension en régression / Dimension reduction in regressionPortier, François 02 July 2013 (has links)
Dans cette thèse, nous étudions le problème de réduction de la dimension dans le cadre du modèle de régression suivant Y=g(B X,e), où X est un vecteur de dimension p, Y appartient à R, la fonction g est inconnue et le bruit e est indépendant de X. Nous nous intéressons à l'estimation de la matrice B, de taille dxp où d est plus petit que p, (dont la connaissance permet d'obtenir de bonnes vitesses de convergence pour l'estimation de g). Ce problème est traité en utilisant deux approches distinctes. La première, appelée régression inverse nécessite la condition de linéarité sur X. La seconde, appelée semi-paramétrique ne requiert pas une telle condition mais seulement que X possède une densité lisse. Dans le cadre de la régression inverse, nous étudions deux familles de méthodes respectivement basées sur E[X f(Y)] et E[XX^T f(Y)]. Pour chacune de ces familles, nous obtenons les conditions sur f permettant une estimation exhaustive de B, aussi nous calculons la fonction f optimale par minimisation de la variance asymptotique. Dans le cadre de l'approche semi-paramétrique, nous proposons une méthode permettant l'estimation du gradient de la fonction de régression. Sous des hypothèses semi-paramétriques classiques, nous montrons la normalité asymptotique de notre estimateur et l'exhaustivité de l'estimation de B. Quel que soit l'approche considérée, une question fondamentale est soulevée : comment choisir la dimension de B ? Pour cela, nous proposons une méthode d'estimation du rang d'une matrice par test d'hypothèse bootstrap. / In this thesis, we study the problem of dimension reduction through the following regression model Y=g(BX,e), where X is a p dimensional vector, Y belongs to R, the function g is unknown and the noise e is independent of X. We are interested in the estimation of the matrix B, with dimension d times p where d is smaller than p (whose knowledge provides good convergence rates for the estimation of g). This problem is processed according to two different approaches. The first one, called the inverse regression, needs the linearity condition on X. The second one, called semiparametric, do not require such an assumption but only that X has a smooth density. In the context of inverse regression, we focus on two families of methods respectively based on E[X f(Y)] and E[XX^T f(Y)]. For both families, we provide conditions on f that allow an exhaustive estimation of B, and also we compute the better function f by minimizing the asymptotic variance. In the semiparametric context, we give a method for the estimation of the gradient of the regression function. Under some classical semiparametric assumptions, we show the root n consistency of our estimator, the exhaustivity of the estimation and the convergence in the processes space. Within each point, an important question is raised : how to choose the dimension of B ? For this we propose a method that estimates of the rank of a matrix by bootstrap hypothesis testing.
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Voedselsekerheid as ontwikkelingsdoelwit in Suid-Afrikaanse wetgewing : 'n menseregte-gebaseerde benadering / Anél TerblancheTerblanche, Anél January 2011 (has links)
Various South African government reports list food security as a development priority. Despite this prioritisation and despite the fact that South Africa is currently food self-sufficient, ongoing food shortages remain a daily reality for approximately 35% of the South African population. The government's commitment to food security to date of writing (being 30 November 2011) manifests in related policies, strategies, programmes and sectoral legislation with the focus on food production, distribution, safety and assistance.
A paradigm shift in the international food security debate was encouraged during 2009, namely to base food security initiatives on the right to sufficient food. During a 2011 visit to South Africa, the Special Rapporteur for the Right to Food of the United Nations, accordingly confirmed that a human rights-based approach to food security is necessary in the South African legal and policy framework in order to address the huge disparities in terms of food security (especially concerning geography, gender and race). A human rights-based approach to food security will add dimensions of dignity, transparency, accountability, participation and empowerment to food security initiatives. The achievement of food security is further seen as the realisation of existing rights, notably the right of access to sufficient food.
The right of access to sufficient food, as entrenched in section 27(1)(b) of the Constitution of the Republic of South Africa, 1996 will accordingly play a central role within a human rights-based approach to food security. Section 27(2) of the Constitution of the Republic of South Africa, 1996 qualifies section 27(1)(b) by requiring the state to take reasonable legislative and other measures, within its available resources, to achieve the progressive realisation of each of the section 27(1) rights. The South African government's commitment to food security, as already mentioned, currently manifests in related policies, strategies and programmes, which initiatives will qualify as other measures as referred to in section 27(2) mentioned above.
This study, however, aims to elucidate the constitutional duty to take reasonable legislative measures as required by section 27(2) within the wider context of food security. This study is more specifically confined to the ways in which a human rights-based approach to food security as a development objective can be accommodated in South African national legislative measures. Hence, this study focuses on three national legislative levels, namely constitutional incorporation, the adoption of a framework law and revision of sectoral legislation.
Several underlying and foundational themes are addressed in the course of this study, amongst others: (a) the development of the food security concept; (b) the relationship between food security and the right of access to sufficient food; (c) key elements of a human right-based approach; and (d) the increasing trend to apply a human rights-based approach to development initiatives in general, but also to food security. / Thesis (PhD (Law))--North-West University, Potchefstroom Campus, 2012
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Voedselsekerheid as ontwikkelingsdoelwit in Suid-Afrikaanse wetgewing : 'n menseregte-gebaseerde benadering / Anél TerblancheTerblanche, Anél January 2011 (has links)
Various South African government reports list food security as a development priority. Despite this prioritisation and despite the fact that South Africa is currently food self-sufficient, ongoing food shortages remain a daily reality for approximately 35% of the South African population. The government's commitment to food security to date of writing (being 30 November 2011) manifests in related policies, strategies, programmes and sectoral legislation with the focus on food production, distribution, safety and assistance.
A paradigm shift in the international food security debate was encouraged during 2009, namely to base food security initiatives on the right to sufficient food. During a 2011 visit to South Africa, the Special Rapporteur for the Right to Food of the United Nations, accordingly confirmed that a human rights-based approach to food security is necessary in the South African legal and policy framework in order to address the huge disparities in terms of food security (especially concerning geography, gender and race). A human rights-based approach to food security will add dimensions of dignity, transparency, accountability, participation and empowerment to food security initiatives. The achievement of food security is further seen as the realisation of existing rights, notably the right of access to sufficient food.
The right of access to sufficient food, as entrenched in section 27(1)(b) of the Constitution of the Republic of South Africa, 1996 will accordingly play a central role within a human rights-based approach to food security. Section 27(2) of the Constitution of the Republic of South Africa, 1996 qualifies section 27(1)(b) by requiring the state to take reasonable legislative and other measures, within its available resources, to achieve the progressive realisation of each of the section 27(1) rights. The South African government's commitment to food security, as already mentioned, currently manifests in related policies, strategies and programmes, which initiatives will qualify as other measures as referred to in section 27(2) mentioned above.
This study, however, aims to elucidate the constitutional duty to take reasonable legislative measures as required by section 27(2) within the wider context of food security. This study is more specifically confined to the ways in which a human rights-based approach to food security as a development objective can be accommodated in South African national legislative measures. Hence, this study focuses on three national legislative levels, namely constitutional incorporation, the adoption of a framework law and revision of sectoral legislation.
Several underlying and foundational themes are addressed in the course of this study, amongst others: (a) the development of the food security concept; (b) the relationship between food security and the right of access to sufficient food; (c) key elements of a human right-based approach; and (d) the increasing trend to apply a human rights-based approach to development initiatives in general, but also to food security. / Thesis (PhD (Law))--North-West University, Potchefstroom Campus, 2012
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RECOMENDAÇÕES DE FERTILIZAÇÃO FOSFATADA E POTÁSSICA PARA AS PRINCIPAIS CULTURAS DE GRÃOS SOB SISTEMA PLANTIO DIRETO NO PARAGUAI / RECOMMENDATION OF PHOSPHATE AND POTASSIUM FERTILIZATION TO THE MAIN GRAIN CROPS UNDER NOTILLAGE IN PARAGUAYRiquelme, Ursino Federico Barreto 06 March 2008 (has links)
The recommendations of fertilization have as main purpose to facilitate and aid the decisions about application of fertilizers necessary to obtain yields of maximum economic
efficiency. Pointing out the importance of the numerical tables indications, should be also important the crops and area history, the history of fertilizations and calcareous use, the yields obtained and expected, the farmer social-economic conditions, the management system and soil type, the area climatic conditions and the environmental impact of the technology used. With the no-till (SPD) adoption in Paraguay, questions appeared about the use of fertilizers technical recommendations, especially of phosphorus (P) and potassium (K), considering that this tables had been elaborated having as base researches accomplished with experiments carried out in soil conventional tillage system (SC). This research aimed to generate recommendations of phosphate and potassium fertilization through experiments of calibration in seven places in the Região Oriental of Paraguay. The experiments, in no-till, were carried out since 2003 to 2006, in soils with different texture and initial levels of fertility, in
representative areas of grains crops production and in areas with known history of no-tillage adoption in the country. In the Misiones Department experiments were carried in two areas (one of medium and another of low fertility, both with the same texture); in the Itapúa Department in two areas (one of high and another of low fertility, with different texture); in the Alto Paraná Department (two areas of low fertility, but with the same texture) and one of low fertility in the Amambay Department. The experimental design used was randomized blocks, with subdivided plots and three replicates. For phosphorus, the main plots were fertilized with five doses of P (0, 50, 100, 200 e 400 kg ha-1 of P2O5) with the purpose to create levels of fertility and seeded with wheat later. In the sub plots were applied four doses of P (0, 40, 80 e 120 kg ha-1 of P2O5) during corn and soybean seeding, aiming to obtain the response curve. For potassium, the treatments were five doses of K2O (0, 25, 50, 75 and 100 kg ha-1), with applications in soil surface before the crops seeding. The doses were applied every planting, respecting the same amounts and in the same plots, which varied in the second phase of the experiments, for the winter of 2005 and summer of 2005-2006. To obtain more points in the response curves in the project second phase, an application of 120 kg of phosphorus was done in the plots with level 200 kg of P2O5, and in the plots of K2O were applied 25 kg of K2O. Were sampled ten soil samples by plot in the depth of 0 to 10 cm before seeding and after crop harvest. The P build level was more influenced by P start level and by areas fertilization history than soil texture. In the soils with low P level and with no fertilization history was necessary to apply 35,4 kg of P2O5 ha-1 to increase 1 mg dm-3 of P in the soil. On the other hand, to soils with intermediate to high level and history of previous fertilizer application was necessary to apply 20,3 kg of P2O5 ha-1 to increase 1 mg dm-3 of P in the soil. Was necessary to add 27,85 kg of P2O5 ha-1 to increase 1 mg dm-3 of P in the soil, when the distinction between soils with or without history of fertilization was not done. To reach the P critical level in the soil, the addition of 210 kg ha-1 of P2O5 is recommended for class "very low", 105 kg ha-1 for class "low" and 30 kg ha-1 for class "medium". The critical level of P was higher than that established by the ROLAS, and the influence of the soil texture was smaller than that previewed by the ROLAS. The critical level for soils with 410-600 g kg-
1 of clay (Class 1) was 12 mg dm-3 and for soils of 210 a 400 g kg-1 of clay (Class 2) was 15 mg dm-3. The critical level determined for soybean, corn and wheat crops were of 15, 10 and 12 mg dm-3, respectively. The K critical level determined by Mehlich-1 for wheat, corn and soybean under no-tillage in the Paraguay is 75 mg dm-3. To reach the K critical level in the soil, the addition of 250 kg ha-1 of K2O is recommended for class "very low", 125 kg ha-1 for class "low" and 40 kg ha-1 for class "medium". It is necessary 5 kg ha-1 of K2O to increase one mg dm-3 of its level in the soil. In K2O soil levels upper 150 mg dm-3, the plants presents low probability of answer to potassium fertilizers application. Smaller relative and absolute yields were obtained with wheat after soybean than after corn. / As recomendações de fertilização têm como principal finalidade facilitar e auxiliar na tomada de decisão de aplicação de fertilizantes, que se necessita para obtenção de
rendimentos de máxima eficiência econômica. Salientando a importância das indicações numéricas das tabelas, devemos também dar importância ao histórico de cultivo e da área, o
histórico de adubação e calagem, as produtividades obtidas e a esperadas, as condições sócioeconômicas do produtor rural, o sistema de manejo e tipo de solo, o clima da região e o
impacto ambiental da tecnologia a ser utilizada. No Paraguai surgiram questionamentos com a adoção do SPD quando se referia a utilização das recomendações técnicas de fertilizantes, especialmente de fósforo (P) e potássio (K), considerando que as mesmas haviam sido elaboradas tendo como base pesquisas realizadas com experimentos conduzidos no sistema convencional (SC) de preparo do solo. O objetivo deste trabalho foi a obtenção de tabelas próprias para a recomendação fosfatada e potássica das principais culturas sob sistema de plantio direto no Paraguai. Os experimentos foram conduzidos desde 2003 a 2006, em solos com diferentes texturas e níveis iniciais de fertilidade, em regiões representativas de produção de grãos e em locais com histórico de adoção do SPD do país. No Departamento de Misiones conduziu-se experimentos em dois locais (um de média e outro de baixa fertilidade inicial com a mesma textura); no Departamento de Itapúa em dois locais (um de alta e o outro de baixa fertilidade inicial com diferente textura); no Departamento de Alto Paraná (dois locais
de baixa fertilidade, porém com diferente textura) e um no Departamento de Amambay de baixa fertilidade. O delineamento experimental foi de blocos ao acaso em parcelas
subdivididas com três repetições. Para o fósforo as parcelas principais foram adubadas com cinco doses de P (0, 50, 100, 200 e 400 kg ha-1 de P2O5) visando a criação de níveis de
fertilidade e semeadas posteriomente com trigo. Nas subparcelas foram aplicadas quatro doses de P (0, 40, 80 e 120 kg ha-1 de P2O5) no momento da implantação do milho e da soja visando a obtenção de curva de resposta. E para o potássio os tratamentos consistiram de cinco doses
de K2O (0, 25, 50, 75 e 100 kg ha-1) e as aplicações foram efetuadas em superfície antes da semeadura das culturas. As doses foram aplicadas em todas as safras, respeitando as mesmas quantidades e nas mesmas parcelas, o que variou na segunda etapa da condução dos experimentos, para as safras de inverno de 2005, e de verão de 2005/2006. Para se obter mais pontos nas curvas de resposta na segunda fase do projeto, foi realizada uma aplicação de 120 kg de fósforo nas parcelas com nível 200 kg de P2O5, e nas parcelas de K2O foram aplicadas 25 kg de K2O. Foram coletadas dez amostras de solo por parcela na profundidade de 0-10 cm antes da semeadura e após a colheita de cada cultura. A construção do nível de P foi mais influenciada pelo teor inicial de P e histórico de adubação das áreas do que pela textura do
solo. Em solos com baixo teor de P e sem histórico de adubação foi necessário aplicar 35,4 kg P2O5 ha-1 para elevar 1 mg dm-3 de P no solo. Por outro lado, para solos com teor médio a alto com histórico de adubação foi necessário aplicar 20,3 kg P2O5 ha-1 para elevar 1 mg dm-3 de P
no solo. E foram necessários adicionar em média geral 27,85 Kg P2O5 ha-1 para elevar 1 mg dm-3 de P no solo, quando não se faz a distinção entre áreas com e sem histórico de adubação. Para atingir o teor crítico de P no solo é recomendada a adição de 210 kg ha-1 de P2O5 para a
classe muito baixo , 105 kg ha-1 para a classe baixo e 30 kg ha-1 para a classe médio . O teor crítico de P foi superior ao estabelecido pela ROLAS, também a influência da textura foi inferior em relação à prevista pela ROLAS. O teor critico para solos de 410-600 g kg-1 de argila (Classe 1) foi de 12 mg dm-3 e para solos de 210 a 400 g kg-1 de argila (Classe 2) foi de 15 mg dm-3. O teor crítico determinado para as culturas de soja, milho e trigo, foram de 15, 10 e 12 mg dm-3, respectivamente. O teor crítico de K no solo determinado por Mehlich-1 para trigo, milho e soja sob sistema plantio direto no Paraguai é de 75 mg dm-3. Para atingir o teor crítico de K no solo é recomendada a adição de 250 kg ha-1 de K2O, quando se encontra na classe muito baixo , 125 kg ha-1 quando se encontra na classe baixo e 40 kg ha-1 quando se
encontra na classe médio . São necessários 5 kg ha-1 de K2O para elevar em um mg dm-3 o teor de potássio no solo. Em teores no solo acima de 150 mg dm-3, as plantas apresentam baixa probabilidade de resposta à aplicação de fertilizantes potássicos. Maiores rendimentos relativos e absolutos foram atingidos com o trigo após a soja do que após o milho.
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Uso do clorofilômetro portátil na determinação da adubação nitrogenada de cobertura em cultivares de feijoeiro /Maia, Suelen Cristina Mendonça, 1986. January 2011 (has links)
Orientador: Rogério Peres Soratto / Banca: Roberto Lyra Villas Boas / Banca: Marcelo Andreotti / Resumo: Técnicas de manejo que possibilitem a maximização de absorção de N pelo feijoeiro são de extrema importância, em razão do alto custo dos fertilizantes nitrogenados e das perdas de N, que podem representar prejuízos aos produtores e riscos ao ambiente. Nesse sentido, a estimativa da necessidade de N pelo feijoeiro mediante a leitura indireta de clorofila, pelo clorofilômetro portátil, pode ser uma alternativa viável. Contudo, ainda existe a necessidade de estabelecimento de critérios para a utilização desse aparelho na cultura do feijão. Os objetivos do presente trabalho foram: a) verificar a correlação entre o índice relativo de clorofila (IRC), obtido mediante leituras do clorofilômetro portátil (SPAD- 502), e o teor de N da folha de dois cultivares de feijão (IAC Alvorada e Pérola) em diversos estádios de desenvolvimento; b) verificar o comportamento do IRC e do índice de suficiência de N (ISN) em função dos manejos de N aplicado em cobertura; c) avaliar o ISN calculado com base nas medidas IRC nas folhas como indicador do momento de aplicação de N em cobertura na cultura do feijão e, d) verificar qual valor do ISN (90% e 95%) em relação ao tratamento referência é o mais adequado para indicar o momento da adubação nitrogenada em cada cultivar utilizado. O trabalho foi constituído de um experimento conduzido durantes as safras "das águas" e "da seca" do ano agrícola 2009/2010, na Fazenda Experimental Lageado da FCA/UNESP - Botucatu-SP. O delineamento experimental foi em blocos ao acaso, em esquema de parcela subdividias, com quatro repetições. As parcelas foram constituídas por dois cultivares de feijão (Pérola e IAC Alvorada) e as subparcelas por seis manejos do N M1: 40 kg ha-1 de N na semeadura + 80 kg ha-1 de N aos 15 dias após a emergência (DAE) + 80 kg ha-1 de N aos 30 DAE; M2: 20 kg ha-1 de N na semeadura... (Complete abstract click electronic access below) / Abstract: Management techniques that allow the maximization of N uptake by bean crop are extremely important, because of high cost of nitrogen fertilizers and N losing, which may represent losses to producers and risks to the environment. In this sense, the estimation of N needs of common bean crop by indirect reading of chlorophyll can be a viable alternative. However, there is remains the need to establish criteria for using this device in the bean. The aims of this study were: a) determine the correlation between relative chlorophyll index (RCI), obtained by reading of chlorophyll (SPAD 502) and leaf N content of two bean cultivars (IAC Alvorada and Pérola) in various stages of development; b) verify the behavior of the RCI and N sufficiency index (NSI) for different sidedressing N management practices; c) evaluated the NSI calculated based on the measures RCI leaves as an indicator of time of N application in sidedressing on bean crop and d) verify that value of NSI (90% and 95%) compared to the reference treatment is most appropriate to indicate the moment of fertilization in each cultivar. The work was composed of an experiment conducted in "rainy" and "dry" season of agricultural year 2009/2010 at the Experimental Lageado Farm FCA/UNESP - Botucatu-SP. A randomized block in split plot scheme, with four replications was used. Plots consisted of two bean cultivars (IAC Alvorada and Pérola) and subplots of six N managements M1: 40 kg ha-1 N at sowing + 80 kg ha-1 at 15 days after emergence (DAE) + 80 kg ha-1 N at 30 DAE; M2: 20 kg ha-1 N at sowing + 40 kg ha-1 N at 15 DAE + 40 kg ha-1 N at 30 DAE; M3: 10 kg ha-1 N at sowing + 20 kg ha-1 N at 15 DAE + 20 kg ha-1 N at 30 DAE; M4: 20 kg ha-1 N at sowing + 30 kg ha-1 N when chlorophyll meter readings indicated NSI <95%; M5: 20 kg ha-1 N at sowing + 30 kg N ha-1 N when chlorophyll meter readings indicated NSI <90% and, M6: control (without nitrogen)... (Complete abstract click electronic access below) / Mestre
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Calibração visando recomendações de fertilização fosfatada para as principais culturas de grãos sob sistema plantio direto no Paraguai / Recommendation of phosphorus fertilization to main grain crops in no-till ParaguaiAndrada, Martín Maria Cubilla 08 August 2005 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / At present time, 60% of the grain crop area in Paraguay is under the no-till (NT)
system. This fact puts the country as a leader in this conservation practice. With the
expansion of NT in the country, some questions were raised with respect to fertilizer
recommendations, specially with Phosphorus (P). Those recommendations were
conducted on the conventional system of soil tillage (plow + disc). The objective of
this work was to conduct calibration studies in seven different locations of the Eastern
Regions of Paraguay, in order to obtain phosphate fertilizer recommendations for
crops such as wheat, corn and soybean under NT system. These experiments were
conducted since 2003 to 2005, with soils with different texture and initial fertility
levels, located on regions that were representative of the grain production area, with
different records of NT adoption. In the Misiones Department, experiments were
carried out in two sites (one with medium and another with high level of initial fertility,
both with same texture); in the Itapúa Department, in two sites (one with high and
another with low initial fertility, both with different textures); in the Department of Alto
Paraná (two sites of low fertility, and with different textures); and one in the
Department of Amambay, with low initial fertility. The experimental design was
random blocks with split plots and three replications. The main plots received five
P205 dosis (0, 50, 100, 200 and 400 kg ha-1) with the objective of building up soil
fertility levels. In these plots wheat were seeded. In the split plot four P205 dosis were
applied for corn and soybean crops in order to obtain the response curve. In each
plot 10 soil samples at 0 to 10 cm depth were taken before seeding and right after
harvest of each crop. The phosphorus source were 0-46-0 fertilizer, denominated
triple super phosphate, being applied over the soil surface. The build up of P was
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more influenced by initial level than by soil texture. In soils with low initial P level it
was necessary to apply 36.5 kg P205 ha-1 to increase 1 mg dm-3 of soil P. In the soils
with medium to high initial P level (with historic of fertilization) it was necessary to
apply 18.6 kg P205 ha-1 to increase 1 mg dm-3 of soil P. The sufficient P level was
higher than that used in Southern Brazil being the influence of texture lesser than as
related by ROLAS, the sufficient P level for soils from 410 to 600 g kg-1 of clay was
12 mg dm-3 and for soils from 210 to 400 g kg-1 of clay was 15 mg dm-3. These
results probably are due to two main reasons: 1) the shallow soil layer sampled (0 to
10 cm) has a higher P concentration in no-till compared to the deeper layer sampled
(0 to 20 cm) in conventional tillage; 2) crops varieties used in these experiments have
more yield potential, and as a result, they have higher nutrient demand as compared
to older varieties used in previous experiments. In conclusion of this research, a
proposal P of fertilization is recommended in NT system in Paraguay. / Atualmente 60% da área de cultivo de grãos do Paraguai utiliza o sistema
de plantio direto (SPD), posicionando o país como um dos líderes nesse sistema
conservacionista. Com a expansão do SPD no país, surgiram questionamentos
quanto à adaptação das recomendações técnicas de fertilização, especialmente
de fósforo (P), pois estas haviam sido elaboradas com base em resultados
obtidos no sistema convencional de preparo de solo (aração + gradagens) e
experimentos conduzidos a pelos uma década atrás. O objetivo deste trabalho foi
à condução de experimentos de calibração em sete diferentes locais na Região
Oriental do Paraguai, visando gerar as recomendações de adubação fosfatada
para as culturas de trigo, milho e soja sob SPD. Os experimentos foram
conduzidos de 2003 a 2005, em solos com diferente texturas e níveis iniciais de
fertilidade, em regiões representativas de produção de grãos e em locais com
histórico de adoção do SPD do país. No Departamento de Misiones conduziu-se
experimentos em dois locais (um de média e outro de baixa fertilidade inicial com
a mesma textura); no Departamento de Itapúa em dois locais (um de alta e o
outro de baixa fertilidade inicial com diferente textura); no Departamento de Alto
Paraná (dois locais de baixa fertilidade, porém com diferente textura) e um no
Departamento de Amambay de baixa fertilidade. O delineamento experimental foi
de blocos ao acaso em parcelas subdivididas com três repetições. As parcelas
principais foram adubadas com cinco doses de P (0, 50, 100, 200 e 400 kg ha-1 de
P2O5) visando a criação de níveis de fertilidade e semeadas posteriomente com
trigo. Nas subparcelas foram aplicadas quatro doses de P (0, 40, 80 e 120 kg ha-1
de P2O5) no momento da implantação do milho e da soja visando a obtenção de
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curva de resposta. Foram coletadas dez amostras de solo por parcela na
profundidade de 0 a 10 cm antes da semeadura e após a colheita de cada cultura.
A fonte de P utilizada foi o superfosfato triplo com as aplicações sendo realizadas
a lanço. A construção do nível de P foi mais influenciada pelo teor inicial de P e
histórico de adubação das áreas do que pela textura do solo. Em solos com baixo
teor de P e sem histórico de adubação foi necessário aplicar 35,3 kg P2O5 ha-1
para elevar 1 mg dm-3 de P no solo. Por outro lado, para solos com teor médio a
alto com histórico de adubação foi necessário aplicar 18,6 kg P2O5 ha-1 para
elevar 1 mg dm-3 de P no solo. O teor crítico de P foi superior ao estabelecido pela
ROLAS, também a influência da textura foi inferior em relação à prevista pela
ROLAS. O teor critico para solos de 410-600 g kg-1 de argila (Classe 1) foi de 12
mg dm-3 e para solos de 210 a 400 g kg-1 de argila (Classe 2) foi de 15 mg dm-3.
Este resultado está relacionado a dois fatores principais: 1) à camada superficial
amostrada (0 a 10 cm) durante a condução do experimento, a qual possui
superior concentração de P, em comparação a camada de 0 a 20 cm; b) maior
potencial produtivo, e conseqüentemente maior demanda por P, das cultivares
utilizadas neste experimento em relação a de experimentos conduzidos
anteriormente. Como conclusão deste trabalho é apresentada uma proposta de
adubação fosfatada adaptada ao SPD no Paraguai.
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Logistika v Povltavských mlékárnách, a.s. / Logistics in Povltavské mlékárny, a. s.Prokůpková, Soňa January 2008 (has links)
The graduation theses is focused on an application of logistics in food company. Theoretical part defines terms like stocking, manipulation units, wraps, material flow etc. The application part is based on the logistics in Povltavské mlékárny, a. s. It describes different departments like purchase (and also program Milsoft), estimates of sale, finished stock room and fleet department. The second part of the application part is based on the thoughts and calculation of sufficient capacity of the finished stock room after implementation of laboratory tests for listeria.
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Second Order Sufficient Optimality Conditions for Nonlinear Parabolic Control Problems with State ConstraintsRaymond, Jean-Pierre, Tröltzsch, Fredi 30 October 1998 (has links)
In this paper, optimal control problems for semilinear parabolic equations with
distributed and boundary controls are considered. Pointwise constraints on the control and on
the state are given. Main emphasis is laid on the discussion of second order sufficient optimality
conditions. Sufficiency for local optimality is verified under different assumptions imposed
on the dimension of the domain and on the smoothness of the given data.
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Exploring vocabulary deficiencies of English first additional language learners at a selected public high school in South Africa, Limpopo ProvinceSeanego, Morobadi Johannes January 2022 (has links)
Thesis (M.A. (English Studies)) -- University of Limpopo, 2022 / Sufficient English vocabulary in language learning is a fundamental tool for academic
success in Further Education and Training (FET). In every school where English is the
medium of instruction, learners are anticipated to be proficient and competent in
English. This is a target language for content comprehension and content engagement
for academic success. The aim of the study was to explore the vocabulary deficiencies
of English First Additional Language (EFAL) learners at a selected public high school
in Limpopo Province, South Africa. A mixed method approach was used to accumulate
the qualitative data and quantify the results. The study used a purposive sampling for
the population of twenty (20) EFAL learners and one (1) EFAL teacher. The data
collection methods in the study incorporated criterion-referenced test, semi-interviews,
and a focus group discussion. The data was analysed thematically. The findings show
that EFAL Grade 10 learners have challenges with EFAL vocabulary deficiencies,
which causes academic failure, delay, and school drop-out. The implication is that
strategic interventions are required to eradicate the vocabulary deficiencies of EFAL
Grade 10 learners in the selected school. The limitation of the study is that it sampled
a small population which does not reflect the predicament of every EFAL Grade 10
learner. However, the findings have shown that vocabulary deficiencies is a challenge
for EFAL Grade 10 learners.
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Optimization and Flow-Invariance via High Order Tangent ConesConstantin, Elena January 2005 (has links)
No description available.
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