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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Análise de pastilhas de plantas por espectrometria de emissão óptica com plasma induzido por laser em regimes temporais de nano- e de femtossegundos / Nanosecond and femtosecond laser-induced breakdown spectroscopy for the analysis of pellets of plant materials

Gabriel Gustinelli Arantes de Carvalho 11 June 2015 (has links)
A influência das variáveis associadas ao laser como a fluência, o comprimento de onda, e a duração do pulso, assim como as relacionadas às propriedades das amostras, como a distribuição do tamanho das partículas e as características químicas da matriz, foram avaliadas visando à determinação quantitativa de macro- (P, K, Ca, Mg) e micronutrientes (Cu, Fe, Mn, Zn, B) em pastilhas de materiais vegetais por espectrometria de emissão óptica com plasma induzido por laser (LIBS). Os efeitos da distribuição do tamanho das partículas e da fluência do laser foram investigados a partir da análise de amostras peneiradas (150-20 µm) empregando-se um sistema LIBS, em regime temporal de nanossegundos (ns-LIBS), montado com um laser de Nd:YAG a 1064 nm (pulsos de 5 ns e 360 mJ)e um espectrômetro com óptica Echelle e detector ICCD. Observou-se um aumento na sensibilidade e na precisão das medições com a diminuição do tamanho das partículas usadas no preparo das pastilhas, e uma diminuição dos efeitos de matriz causados por diferenças no tamanho das partículas, quando pastilhas preparadas com partículas < 75 µm foram analisadas com pulsos de 50 J cm-2. Verificou-se uma melhora significativa na exatidão das medições de Mg, Fe, Mn e Zn feitas em um conjunto de pastilhas de folhas de cana-de-açúcar (partículas < 75 µm) empregando-se esta fluência. Em uma segunda etapa, observou-se que variações no comprimento de onda do laser de Nd:YAG (1064, 532, 355 e 266 nm) não influenciaram de maneira significativa a precisão e exatidão das medições em pastilhas de folhas de cana-de-açúcar, obtendo-se correlações lineares entre as intensidades dos sinais de emissão e as correspondentes frações de massa dos analitos. Variações no comprimento de onda do laser de Nd:YAG não afetaram a análise de um conjunto heterogêneo de amostras, composto por pastilhas de folhas de plantas de diferentes espécies, como soja, cana-de-açúcar, milho, citros, café, por exemplo, por ns-LIBS. No entanto, diferentemente do observado para o conjunto de pastilhas de folhas de cana-de-açúcar, observou-se, uma baixa correlação (r cal < 0,90) entre as frações de massa de Ca, Mg, P, Cu, Fe, Mn e Zn determinadas por ns-LIBS e os valores de referência, o que demonstra a baixa robustez de ns-LIBS frente às variações na composição química das matrizes. Posteriormente, analisou-se este conjunto heterogêneo de amostras com sistema LIBS, em regime temporal de femtossegundos (fs-LIBS), montado com laser de Ti:Safira (pulsos de 60 fs e 1,65 mJ) e espectrômetro com óptica Czerny-Turner e ICCD. Demonstrou-se que o uso de pulsos em regime de fs proporcionou calibrações e validação menos dependentes da composição química das matrizes. As frações de massa de Ca, Mg, P, Fe e Mn previstas por fs-LIBS foram estatisticamente concordantes com os valores de referência, independentemente do modelo de calibração usado. Além disso, o uso de calibração multivariada melhorou a capacidade preditiva de ns-LIBS, assemelhando-se à de fs-LIBS. Concluiu-se que o emprego de fs-LIBS foi a estratégia mais robusta e que ofereceu maior flexibilidade à variabilidade matricial / The influence of laser properties, such as fluence, wavelength and pulse duration, as well as sample characteristics, such as particle size distribution and chemical matrix composition, was evaluated aiming at the quantitative determination of macro- (P, K, Ca, Mg) and micronutrients (Cu, Fe, Mn, Zn, B) in pellets of plant materials by laser-induced breakdown spectroscopy (LIBS). Firstly, the effects of particle size distribution and laser fluence on the analysis of pellets (test samples) prepared with sieved samples (from 150 to 20 µm apertures) were investigated. Experiments were carried out with a nanosecond LIBS (ns-LIBS) system by using a Q-switched Nd:YAG laser at 1064 nm (5 ns; 360 mJ) and a spectrometer with Echelle optics and intensified charge-coupled device (ICCD) detector. Results indicated that smaller particles yielded to sensitivities\' enhancement and attained better measurements\' precision. Moreover, matrix effects were reduced by analyzing pellets prepared from < 75 ?m sieved fractions and pulses of 50 J cm-2. In addition, there was a significant improvement on accuracy of Mg, Fe, Mn and Zn measurements in a set of test samples of sugarcane leaves by using this fluence. In a second experiment, variations in the Nd:YAG laser wavelength (1064, 532, 355 and 266 nm) did not affect the analysis of test samples of sugarcane leaves, and provided linear correlations between emission signal intensities and corresponding analytes mass fractions. In addition, variations within Nd:YAG laser wavelength did not affect the analysis of a heterogeneous sample set composed by pellets of leaves from different crops, such as soy, sugarcane, maize, citrus and coffee by ns-LIBS. However, in contrast to previous findings, the univariate calibration models for ns-LIBS presented lower linearity (r cal < 0.90) for Ca, Mg, P, Cu, Fe, Mn and Zn, no matter the laser wavelength used for the analysis. These circumstances reflect the low robustness of ns-LIBS to variations within matrix chemical composition among test samples. Afterwards, test samples from different crops were analyzed by a femtosecond LIBS (fs-LIBS) by using a Ti:Sapphire laser, including a mode-locked oscillator and an ultrafast amplifier (60 fs; 1.65 mJ per pulse), and a spectrometer with Czerny-Turner optics and ICCD. Findings indicated that the pulse duration was a decisive variable for providing accurate quantification of nutrients in different plant species, which present substantial differences in terms of matrix chemical composition. Close agreement between Ca, Mg, P, Fe and Mn mass fractions predicted by fs-LIBS and those determined by ICP OES was evidenced, whatever the modeling approach used. Contrarily, for ns-LIBS analysis of test samples from different crops, only the use of multivariate partial least squares (PLS) regression appears capable for resolving the non-linear transformations of the emission intensities according to the physical mechanisms governing this temporal regime of ablation. Thus, when using multivariate modeling, the figures-of merit reflecting the predictive capabilities of ns-LIBS resemble to those achieved by fs-LIBS. Either way, fs-LIBS is a more robust approach that better offers larger flexibility to the matrix variability
222

Alimentos ultraprocessados e a qualidade nutricional das dietas dos EUA / Ultra-processed foods and the nutritional quality of US diets

Eurídice Martínez Steele 31 May 2017 (has links)
Introdução: A introdução da agricultura e pecuária foram muito recentes para que o genoma humano se adaptasse e a tecnologia avançada pós revolução Industrial foi ainda mais. Segundo Cordain, a substituição de alimentos minimamente processados por alimentos pós-agrícolas e pós-industriais influenciaram os indicadores nutricionais: carga glicêmica, composição de ácidos graxos e macronutrientes, densidade de micronutrientes, equilíbrio ácido-base, relação sódio/potássio e teor de fibras, levando a um desequilíbrio que é causa de várias doenças atuais da civilização. A Protein Leverage Hypothesis (PLH) propõe que a queda na ingestão de proteínas possa levar a obesidade e doenças cardiometabólicas associadas. Objetivos: Estudar o efeito do consumo de alimentos ultraprocessados nos indicadores nutricionais na população dos EUA, incluindo a composição de macronutrientes, densidade de fibras e micronutrientes e fitoestrógenos urinários; avaliar se a contribuição calórica de alimentos ultraprocessados é determinante para a qualidade nutricional das dietas contemporâneas; e finalmente estudar se a associação entre o consumo de alimentos ultraprocessados, proteína e energia correspondem às previsões do modelo PLH. Métodos: Foram avaliados os participantes do National Health and Nutrition Examination Survey 2009-2010, com pelo menos um recordatório alimentar de 24 horas. Os itens foram classificados em: alimentos in natura ou minimamente processados, processados, ultraprocessados e ingredientes de uso culinário. O manuscrito 1 examina a relação entre a contribuição calórica de alimentos ultraprocessados e qualidade nutricional da dieta, avaliando individual e globalmente a contribuição de cada ingrediente crítico, usando a análise de componentes principais (ACP). O manuscrito 2 estuda a associação entre a contribuição calórica dos alimentos ultraprocessados e consumo de açúcares de adição. O manuscrito 3 avalia como o consumo de alimentos ultraprocessados influencia o conteúdo proteico relativo da dieta e as ingestões absolutas de energia e proteína, e se essas relações se encaixam nas previsões da PLH. O manuscrito 4 avalia a relação entre a contribuição calórica de alimentos ultraprocessados e níveis de fitoestrógenos urinários. Resultados: O teor médio de proteínas, fibras, vitaminas A, C, D e E, zinco, potássio, fósforo, magnésio e cálcio na dieta diminuiu ao longo dos quintis de contribuição calórica de alimentos ultraprocessados, enquanto o de carboidratos, açúcares de adição e gordura saturada aumentou. Uma associação inversa de dose-resposta foi encontrada entre o consumo de alimentos ultraprocessados e qualidade nutricional total, medida através de um escore de padrão balanceado de nutrientes derivado usando ACP. Consistente com a PLH, a contribuição calórica de alimentos ultraprocessados foi inversamente associada à densidade proteica e diretamente ao consumo energético total, enquanto a ingestão absoluta de proteínas permaneceu constante com aumento do consumo de alimentos ultraprocessados. Os níveis médios de enterolignanos urinários diminuíram ao longo dos quintis de consumo de alimentos ultraprocessados, enquanto os níveis de isoflavonas permaneceram inalterados. Conclusões: Este estudo mostra que a diminuição da contribuição calórica de alimentos ultraprocessados é um meio racional e eficaz de melhorar a qualidade nutricional das dietas dos EUA / Background: The introduction of agricultural and animal husbandry has not provided the human genome time enough to adapt, much less the advancing technology after Industrial Revolution. According to Cordain et al., displacement of minimally processed foods by post-agricultural and post-industrial food items adversely affected the following dietary indicators: glycemic load, fatty acid and macronutrient compositions, micronutrient density, acid-base balance, sodium-potassium ratio and fiber content. Many current diseases of civilization, in turn may be ascribable to those unbalanced dietary indicators. Indeed, Raubenheimer and Simpson have proposed the Protein Leverage Hypothesis (PLH) to explain how a drop in dietary protein content might lead to obesity and associated cardiometabolic disease. Objective: This thesis aims to study the effect of an increased consumption of ultra-processed foods on dietary indicators in the US population, including macronutrient composition, micronutrient and fiber densities, and urinary phytoestrogens. It also explores whether the dietary share of ultra-processed foods, expressed as a percentage of total energy intake, is a meaningful determinant of overall nutritional quality of contemporary diets. Lastly, it also looks into whether the association between ultra-processed food, protein and energy consumptions fit predictions of the PLH model. Methods: Participants from cross-sectional 2009-2010 National Health and Nutrition Examination Survey with at least one 24-hour dietary recall were evaluated. Food items were classified according to extent and purpose of industrial food processing as: unprocessed or minimally processed foods, processed culinary ingredients, processed foods and ultra-processed foods. Manuscript 1, examines the relationship between dietary contribution of ultra-processed foods and nutritional quality of US diet through the evaluation of dietary contents of critical nutrients individually and also overall, using Principal Component Analysis (PCA). Manuscript 2 studies the association between dietary contribution of ultra-processed foods and energy intake from added sugars. Manuscript 3 examines how consumption of ultra-processed food influences relative dietary protein content and, absolute energy and protein intakes; it furthermore, tests whether the relationships fit PLH predictions. Manuscript 4 assesses the relationship between dietary contribution of ultra-processed foods and urinary levels of phytoestrogens. Results: The average content of protein, fiber, vitamins A, C, D and E, zinc, potassium, phosphorus, magnesium and calcium in US diet decreased significantly across quintiles of energy contribution of ultra-processed foods, while carbohydrate, added sugars and saturated fat contents increased. An inverse dose-response association was found between ultra-processed food consumption and overall dietary quality measured through a Nutrient balanced pattern PCA derived factor score. Consistent with PLH, dietary contribution of ultra-processed foods was inversely associated with protein density and directly associated with total energy intake, while absolute protein intake remained relatively constant with increases in ultra-processed food consumption. Average urinary mammal lignan levels decreased across quintiles of ultra-processed food consumption, while isoflavone levels remained unchanged. Conclusions: This study suggests that decreasing the dietary share of ultra-processed foods is a rational and effective way to improve the nutritional quality of US diets
223

Clonagem de porta-enxertos e produção de mudas de pessegueiro em sistemas de cultivo sem solo / Cloning of rootstocks and production of peach seedlings without soil cultivation system

Tomaz, Zeni Fonseca Pinto 08 March 2013 (has links)
Made available in DSpace on 2014-08-20T14:22:03Z (GMT). No. of bitstreams: 1 tese_zeni_tomaz.pdf: 2323992 bytes, checksum: 4753b60461199c97ba5226db1bc6663b (MD5) Previous issue date: 2013-03-08 / The objective of this study to get peach seedlings without soil cultivation system, from of rootstocks cloned through minicutting. The experiment was conducted in a greenhouse with controlled temperature located in the Didactic Field and Experimental Plant Science Department, Federal University of Pelotas (UFPel-RS), in the period from March 2010 to November 2011. Were evaluated variables relating to the rooting percentage of minicutting; the survival of minicutting after transplanting cultivation systems; height (cm); the lateral shoot number; the diameter (mm) at the base, 10 and 15cm; the foliar contents of macronutrients and micronutrients of rootstocks; the index of establishment; the lateral shoot number and the height of the cultivation of grafted Cup. The obtained results demonstrated that in article 3 the rootstock 'Capdeboscq' presented surviving 80% percentage in soilless cultivation system. The system of cultivation without soil improves the self-rooted of peach seedlings development, article 2, in relation to production in packaging. The rootstocks of Okinawa and Flordaguard cultivars, articles 1 and 3, were on average 70% of the index of establishment when grafted 'Maciel' in system of cultivation without soil. The average content of macronutrients presents similar relationship for macronutrients determined by leaf analysis, sampled in peach orchards, producing region of Pelotas. Clonal rootstocks provide greater height of scion grafted, articles 4 and 5. The system of cultivation without soil allows plants to have a rapid development, with reduction of vegetative cycle time, and reduction of the time for the obtaining of seedlings. / Objetivou-se com o presente estudo obter mudas de pessegueiro em sistema de cultivo sem solo, a partir de porta-enxertos clonados através da miniestaquia. O experimento foi realizado em casa de vegetação com temperatura controlada e em estufa agrícola localizadas no Campo Didático e Experimental do Departamento de Fitotecnia, Faculdade de Agronomia Eliseu Maciel da Universidade Federal de Pelotas (UFPel/RS), no período de março de 2010 a novembro de 2011. Foram avaliadas variáveis referentes à porcentagem de miniestacas enraizadas; a sobrevivência das miniestacas após o transplantio para os sistemas de cultivo; o comprimento (cm); o número de brotações laterais; os diâmetros (mm) na base, 10 e 15cm; o conteúdo foliar de macronutrientes e micronutrientes dos porta-enxertos; o índice de pega da enxertia; o número de brotações laterais e a comprimento da cultivar copa enxertada. Os resultados obtidos demonstraram que no artigo 3 Capdeboscq‟ apresentou 80% de porcentagem de sobrevivência em sistema de cultivo sem solo. O sistema de cultivo sem solo melhora o desenvolvimento das mudas autoenraizadas de pessegueiro, artigo 2, em relação à produção em embalagens. Os porta-enxertos das cultivares Okinawa e Flordaguard, artigos 1 e 3, apresentaram em média 70% de índice de pega quando enxertado Maciel‟ em sistema de cultivo sem solo. O teor médio dos macronutrientes apresenta relação semelhante naqueles determinados pela análise foliar, em amostras colhidas em pomares de pessegueiro, da região produtora de Pelotas. Os porta-enxertos clonais proporcionam maior altura de cultivar copa enxertada, artigos 4 e 5. O sistema de cultivo sem solo permite que as plantas tenham um desenvolvimento acelerado, com diminuição do ciclo vegetativo, podendo diminuir o tempo de obtenção de mudas.
224

Impact d'un régime riche en saccharose sur la sarcopénie chez le rat âgé ; Conséqences métaboliques au niveau hépatique et cérébral. Effets préventifs d'un mélange de micronutriments. Spécialité / The impact of a high sucrose diet on sarcopenia in aging rats. Metabolic consequences on liver and brain. Preventive effects of a micronutrients supplementation.

Gatineau, Eva 20 October 2015 (has links)
Au cours du vieillissement, l’organisme subit de nombreuses altérations, dont une perte de masse et de fonction musculaire appelée sarcopénie. Ses causes sont multifactorielles. Elle est partiellement liée à une altération de la stimulation de la synthèse protéique musculaire post-prandiale, et certains facteurs tels que le stress oxydant, l’inflammation et la résistance à l’insuline, responsables de nombreux dysfonctionnements métaboliques, accélèrent ce phénomène. Or, ces dérégulations peuvent être induites par une alimentation trop riche en sucres ajoutés, caractéristique des habitudes alimentaires actuelles et qui pourrait donc accélérer le vieillissement. Pourtant, à ce jour, peu d'études ont étudié les effets combinés du vieillissement et d'un régime riche en sucres ajoutés, et à notre connaissance, aucune ne s’est intéressée à la sarcopénie. Ainsi, notre objectif au cours de cette thèse a été de déterminer si un régime riche en sucres ajoutés était capable d'accélérer la sarcopénie. Il était également intéressant d'étudier les effets combinés du vieillissement et de ce régime sur d'autres tissus qui semblent particulièrement exposés, le foie, et le cerveau. Enfin, nous avons également voulu analyser les effets préventifs d'un mélange de micronutriments à la fois in vivo et in vitro. Pour cela, des rats âgés de 16 mois ont été nourris durant 5 mois avec un régime contrôle ou un régime composé à 62% de saccharose, supplémenté ou non en rutine, vitamine A, vitamine E, vitamine D, zinc, et sélénium. En outre, nous avons également inclut un groupe de témoins adultes (8 mois), nourris avec un régime contrôle. Par ailleurs, les effets anti-inflammatoires des micronutriments ont été testés in vitro.Nous avons pu constater que le régime riche en saccharose a accéléré la perte de masse musculaire liée à l’âge en altérant la synthèse protéique musculaire post prandiale, vraisemblablement via l’altération de la sensibilité à l’insuline plutôt que par une augmentation du stress oxydant et de l'inflammation, qui ont été peu affectés par le régime. Il a également entraîné un gain de masse grasse et une augmentation marquée des triglycérides hépatiques et plasmatiques, qui pourraient en partie s’expliquer par une modification de l’activité des enzymes du métabolisme lipidique dans le foie. Au niveau cérébral, la surconsommation de fructose a entraîné une diminution de la concentration protéique qui ne semble pas due à un défaut de synthèse protéique. La supplémentation en micronutriments n’a que partiellement contrecarré les effets du saccharose puisqu’elle n’a pas eu d’effet sur la masse maigre mais a permis de limiter la prise de masse grasse, notamment en inhibant la lipogenèse hépatique. Elle a également restauré la synthèse protéique diminuée au cours du vieillissement dans le cerveau. In vitro, elle a permis de réduire l'inflammation induite expérimentalement.Ainsi, cette thèse a permis de montrer qu’un régime riche en sucres ajoutés accélère la sarcopénie chez le rat âgé mais entraîne également des altérations au niveau hépatique et cérébral. La prévention par les micronutriments testés reste malgré tout limitée. / With aging, several alterations occur, including a loss of muscle mass and function, called sarcopenia. Many factors are responsible for the development of sarcopenia, but some factors as inflammation, oxidative stress and insulin resistance, which have many deleterious effects during aging, can reduce meal-induced stimulation of muscle protein synthesis which was shown to partly explain age-related muscle mass loss. Those factors can be induced by a diet rich in added sugar, characteristic of current dietary habits. Although this kind of diet could accelerate aging features, little is known about combined effect of aging and high sugar diet, particularly on sarcopenia. Thus, the purpose of this work was to determine whether high chronic intake of added sugars could accelerate sarcopenia. We also interested in the combined effect of added sugars and aging on other exposed tissues: liver and brain. Finally, we assessed the preventive effects of a micronutrient supplementation both in vivo and in vitro.In order to do that, for 5 months, 16 month old rats were starch fed or sucrose fed (62% sucrose), with or without micronutrients supplementation (rutin, vitamin A, vitamin E, vitamin D, selenium and zinc). Additionally, an adult control group of 8 month old rats was included. Besides, anti-inflammatory effects of micronutrients were tested in vitro.We showed that high sucrose diet accelerated age-related muscle mass loss by impairing postprandial protein synthesis, likely through decreased insulin sensitivity since inflammation and oxidative stress were only slightly affected by high sucrose diet. This diet also resulted in fat mass gain and increased plasma and liver triglycerides, by modulating the activity of enzymes involved in liver lipid metabolism. In the brain, high sucrose consumption led to decreased protein concentration independently of protein synthesis alteration. Micronutrients supplementation only partially reversed high sucrose diet effects: it did not act on lean body mass but prevented fat mass gain, by inhibiting hepatic lipogenesis. It also restored brain protein synthesis, which was reduced by aging. In vitro, it reduced experimentally induced inflammation.Thus, this work showed that a high sucrose diet accelerates sarcopenia in old rats but also induces liver and brain alterations. Prevention by micronutrients remained limited.
225

Factores de riesgo para la baja adherencia a la suplementación con multimicronutrientes en niños de 6 a 35 meses de edad en Apurímac, Ayacucho y Huancavelica durante los años 2009-2011

Trelles Zaracondegui, Sebastian 06 February 2021 (has links)
El objetivo de este estudio fue encontrar los factores de riesgo para la baja adherencia a la suplementación con multimicronutrientes (MMN) en niños de 6 a 35 meses de edad. Se analizó una base de datos secundaria de la vigilancia centinela realizada durante los años 2009-2011 en las regiones de Apurímac, Ayacucho y Huancavelica por el Centro Nacional de Epidemiologia, Prevención y Control de Enfermedades del Perú (CDC). Se incluyeron los datos demográficos además de otras variables que se recogieron mes a mes durante la vigilancia. Estas son si recibió consejería nutricional, si asistió a la sesión demostrativa de preparación de alimentos con MMN, si percibió alguna mejoría en el niño, si el niño presentó algún evento adverso relacionado al consumo de MMN, si recibió visitas domiciliarias, y el alimento en el que se agregó los MMN. Para el análisis estadístico se usó la regresión de ecuaciones de estimación generalizadas (GEE). Los resultados que se encontraron son que asistir a la sesión demostrativa (p=0.005), que el niño presente eventos adversos relacionados a la ingesta de MMN durante los seis primeros meses de suplementación (p<0.001) y agregar los MMN en alimentos líquidos (p=0.001) disminuyen la adherencia a la suplementación en 1.27%, 17.00% y 1.51% respectivamente. Residir en Huancavelica (p<0.001) y que la madre note a su niño más despierto (p=0.039) incrementan la adherencia en 2.51% y 0.95% respectivamente. Concluimos que se deben realizar intervenciones que aborden estos factores de riesgo, y recomendamos que se realicen más estudios en esta área. / The objective of this study was to find the risk factors for poor adherence to multimicronutrient supplementation (MMN) in children 6 to 35 months of age. A secondary database of sentinel surveillance carried out during the years 2009-2011 in the regions of Apurímac, Ayacucho and Huancavelica by the National Center for Epidemiology, Prevention and Disease Control of Perú (CDC) was analyzed. Demographic data was included in addition to other variables that were collected month by month during the surveillance. These are if they received nutritional counseling, if they attended the food preparation demonstration session with MMN, if they perceive any improvement in the child, if the child presented any adverse event related to MMN consumption, if they received home visits, and the food in which the MMNs were added. Regression of generalized estimating equations (GEE) was used for statistical analysis. The results that were found are that attending the demonstration session (p = 0.005), that the child presents adverse events related to the ingestion of MMN during the first six months of supplementation (p <0.001) and adding MMN in liquid foods (p = 0.001) decrease adherence to supplementation by 1.27%, 17.00% and 1.51% respectively. Residing in Huancavelica (p <0.001) and having the mother notice the child more awake (p = 0.039) increases adherence by 2.51% and 0.95% respectively. We conclude that interventions that address these risk factors should be performed, and we recommend that further studies be conducted in this area. / Tesis
226

Analysis of the dietary taboos affecting dietary diversity of women of reproductive age in the South and Grand’Anse departments of Haiti

Arasimowicz, Sabrina 08 1900 (has links)
Contexte. La sous-nutrition est un problème de santé publique, surtout pour les femmes et les enfants dans les pays en voie de développement. Des tabous alimentaire pour cette population existent dans plusieurs régions du monde. Ce mémoire décrit la recherche sur les tabous alimentaires et les facteurs qui peuvent influencer la diversité alimentaire des femmes en âge de procréer. Cette recherche fait partie d’un projet d’intervention qui vise à réduire la mortalité maternelle et infantile dans le Sud et la Grand’Anse d’Haïti, un pays où environ la moitié des femmes en âge de procréer sont anémiques et un tier des enfants d’âge préscolaire ont une carence en vitamine A (WHO 2009, ICF 2018). Objectifs. L’objectif de ce projet est d’identifier et comprendre les tabous alimentaires qui existent chez les femmes enceintes et allaitantes dans la région. Un deuxième objectif est d’identifier les déterminants de la diversité alimentaire des femmes en âge de procréer et de déterminer si les femmes enceintes ou allaitantes ont une alimentation moins diversifiée que les femmes qui ne le sont pas. Méthode. Le devis mixte combine la recherche qualitative et quantitative. Les données qualitatives ont été recueillies avec des groupes de discussion. Pour la collecte de données quantitatives, des entretiens ont été menées auprès de mères d’enfants de moins de cinq ans, suivi par un relevé alimentaire de 24 heures. La diversité alimentaire des participantes a été évaluée avec la DAM-F de la FAO. Les déterminants de la diversité alimentaire ont été identifiés avec des analyses de régression logistique. Résultats. Les participantes des groupes de discussion ont identifié plus de 100 tabous alimentaires. La diversité alimentaire a été influencée par la région, ainsi que les caractéristiques du ménage et de la mère. Les femmes allaitantes atteignent moins souvent une diversité alimentaire minimale et consomment moins souvent les aliments des « autres légumes » et « autres fruits », mais ces résultats sont significatifs seulement dans le modèle non ajusté. Conclusion. Les tabous alimentaires pour les femmes enceintes ou allaitantes existent dans le Grand’Anse et le Sud d’Haïti. Il y a une grande variété de croyances entre les communautés et même dans la même commune. Ces restrictions alimentaires peuvent diminuer la consommation de micronutriments comme la vitamine A et le fer dans une population déjà à risque de malnutrition. Des messages clés à inclure dans les activités éducatives du projet vont être formulés à partir des résultats de la recherche. / Context. Undernutrition, including micronutrient deficiencies, is a global public health issue, particularly for women and children in developing countries. Dietary taboos in this population have been found to exist in many regions of the world, including in Haiti. This thesis describes research looking at dietary taboos and other factors impacting dietary diversity of Women of Reproductive Age (WRA). It is part of an intervention project aiming to decrease maternal and child mortality in the South and Grand’Anse of Haiti, a country where approximately half of WRA are anemic and one third of preschool-age children are deficient in vitamin A (WHO 2009, ICF 2018). Objectives. The objective of this research is to identify and understand food taboos for pregnant and breastfeeding women in the area, to determine what factors influence dietary diversity of WRA and if pregnant or breastfeeding women consume a diet that is less diverse than that of a woman who is not. Methodology. The research design included both qualitative and quantitative components. Qualitative data regarding food taboos was collected through focus groups. Quantitative data was collected through surveys and 24-hour recalls done with WRA who have a child under the age of five. Dietary diversity of survey participants was assessed using the FAO’s MDD-W and it’s determinants were analyzed through adjusted logistic regression calculations. Results. The focus groups revealed over 100 dietary taboos. Determinants of dietary diversity were related to the region, as well as characteristics of the household and mother. Breastfeeding women were less likely to attain the MDD-W and to consume “other fruits” and “other vegetables” though these findings were only significant in the non-adjusted model. Conclusion. Dietary taboos exist in the Grand’Anse and South areas of Haiti for pregnant and breastfeeding women. These taboos vary largely between communes and even within the same community. The restriction of these foods could negatively impact the dietary intake of many micronutrients, including vitamin A and iron. Key messages to include at educative activities through the intervention project will be formed based on results of this work.
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Slurry injection to optimize nutrient use efficiency in maize: Soil nitrogen dynamics and plant nutrient status / Gülle-Depotapplikation zur Optimierung der Nährstoffnutzungseffizienz im Maisanbau: Bodenstickstoffdynamik und Pflanzennährstoffstatus

Westerschulte, Matthias 01 September 2017 (has links)
Maize is the dominant crop in northwestern Germany and is mostly cultivated on sandy soils. Additionally, due to intensive livestock husbandry and biogas production, large amounts of liquid manures are produced. The current farm practice leads to high N and P surpluses at field level accompanied by environmental pollution, like nitrate leaching, eutrophication of non-agricultural ecosystems, and N2O emissions. The accruing liquid manures are often used for maize fertilization. Thereby, slurries are mainly broadcast applied using trailing hose applicators followed by incorporation into the topsoil. In addition, a mineral N P starter fertilizer (MSF) is band-applied below the seed-corn at planting to overcome the limited nutrient availability during the early growth stages. Using a slurry injection technique below the maize row before planting might serve a substitute for MSF. Addition of a nitrification inhibitor (NI) into the slurry before injection seems to be an option to further decrease N losses. The objectives of this thesis were to compare the current and novel fertilizing strategies with a special focus on soil mineral nitrogen (SMN) dynamics and plant P, zinc (Zn) and manganese (Mn) status. For both issues the effect of adding a NI into the slurry was investigated. To characterize the SMN dynamics after slurry injection an appropriate soil sampling strategy had to be developed. Therefore, three consecutive field trials were conducted. The first testing of the new soil sampling approach was implemented in an existing experiment where the slurry was injected at a depth of 12 cm (upper rim) below the soil surface. The soil profile (75 cm wide) centered below the maize row was sampled using a grid-like approach to a depth of 90 cm. Around the injection zone, soil monoliths (SM) were sampled using a purpose-built soil shovel. Below the SMs and in the interrow space (15 and 30 cm distance to the row) a standardized auger procedure was used. The second experiment aimed to improve the sampling strategy with focus on sample homogenization quality and necessary sample sizes per pooled sample. In the third experiment this improved sampling strategy was validated. Results from the first testing of the sampling procedure showed that the strategy is suitable, although some problems occurred. Especially the high spread in values among the replications caused high coefficients of variation (CV; mostly 40 – 60%). The improvement trial revealed that for the SM, which contains the slurry band, an intensive homogenization is required. In addition, suitable sample sizes (twelve auger samples and six soil monolith samples per pooled sample) have to be collected to obtain reliable SMN values. Following this enhanced sampling strategy in the final validation trial, the spread in values was considerably reduced and resulted in CV values of mostly < 20%. The method can be adapted to other fertilizer placement strategies and further row crops. To compare both fertilizing strategies with respect to the spatial and temporal SMN dynamics as well as to the plant nutrient status two field trials were conducted using pig slurry on sandy soils in 2014 and 2015. Four treatments were tested: unfertilized control, broadcast application + MSF, injection, and injection + NI. Soil samples were taken using the new sampling strategy at several dates during the growing season. Plant samples were simultaneously collected to evaluate the plant P, Zn, and Mn status at different growth stages. In 2014, all fertilized N was displaced from the top soil layer of the broadcast treatment until the 6-leaf stage due to heavy rainfall, while N displacement was significantly smaller after slurry injection. The lateral movement of injected slurry N was negligible. In 2015, almost no displacement of fertilized N out of the top soil layer occurred independently of treatments, due to distinctly lower rainfall. The release of slurry N was delayed following broadcast application and large SMN concentrations were detected in the injection zones until the 10-leaf stage. The addition of a NI resulted in significantly increased NH4-N shares in the injection zone throughout the early growth stages (+ 46% in 2014 and + 12% in 2015 at 6-leaf stage). Thus, in 2014 SMN displacement was delayed, and in 2015 increased SMN concentrations were found around the slurry band, most probably due to lower N losses via denitrification. Furthermore, NI addition significantly increased the nutrient uptake by maize during early growth in both years. With P deficiency due to cold weather conditions in 2015, broadcast application showed higher P uptake until the 6-leaf stage (36 – 58%), while it was lower at the 8- (32%) and 10- (19%) leaf stages compared to slurry injection (+ NI). Zn availability was enhanced during early growth after slurry injection (+ NI) and Zn as well as Mn uptake were higher at harvest. Furthermore, dry matter yields were higher (2014) or equal (2015) compared to broadcast application. The P balances were decreased by 10 – 14 kg P ha-1, while Zn and Mn balances were excessive independent of treatments. The field trials showed that after slurry injection, especially when combined with a NI, the applied nitrogen is located in a soil zone with better spatial availability for plant roots compared to broadcast application. Furthermore, the MSF can be substituted without affecting early growth of maize. In conclusion, slurry injection leads to equal (or even higher) yields and enables farmers in northwestern Germany to reduce the P and N surpluses. This would support several goals concerning sustainable land use: Lower pollution of ground and surface waters, reduced emission of NH3, more efficient use of the limited rock P reserves, and less need of transporting organic manures out of regions with intensive animal husbandry and/or biogas production. However, slurry injection enhances the risk of N2O emissions, which contributes to climate change. Thus, for a final evaluation of the environmental impact a life cycle assessment would be worthwhile.
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Investigating the porphyrias through analysis of biochemical pathways.

Ruegg, Evonne Teresa Nicole January 2014 (has links)
ABSTRACT The porphyrias are a diverse group of metabolic disorders arising from diminished activity of enzymes in the heme biosynthetic pathway. They can present with acute neurovisceral symptoms, cutaneous symptoms, or both. The complexity of these disorders is demonstrated by the fact that some acute porphyria patients with the underlying genetic defect(s) are latent and asymptomatic while others present with severe symptoms. This indicates that there is at least one other risk factor required in addition to the genetic defect for symptom manifestation. A systematic review of the heme biosynthetic pathway highlighted the involvement of a number of micronutrient cofactors. An exhaustive review of the medical literature uncovered numerous reports of micronutrient deficiencies in the porphyrias as well as successful case reports of treatments with micronutrients. Many micronutrient deficiencies present with symptoms similar to those in porphyria, in particular vitamin B6. It is hypothesized that a vitamin B6 deficiency and related micronutrient deficiencies may play a major role in the pathogenesis of the acute porphyrias. In order to further investigate the porphyrias, a computational model of the heme biosynthetic pathway was developed based on kinetic parameters derived from a careful analysis of the literature. This model demonstrated aspects of normal heme biosynthesis and illustrated some of the disordered biochemistry of acute intermittent porphyria (AIP). The testing of this model highlighted the modifications necessary to develop a more comprehensive model with the potential to investigated hypotheses of the disordered biochemistry of the porphyrias as well as the discovery of new methods of treatment and symptom control. It is concluded that vitamin B6 deficiency might be the risk factor necessary in conjunction with the genetic defect to trigger porphyria symptoms.

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