The dietary and medicinal uses of indigenous green vegetables were studied quantitatively over a 13-month period in a rural, semi-rural and urban K'ekchi population in Guatemala. Seventeen species of indigenous greens were consumed, with seasonal variation in intake (p $<$.001) being related to agricultural practices. There was a lower frequency of consumption of greens among the urban group (p $<$.001). Within, and between, the communities, individuals exhibited heterogeneity in dietary intake and approaches to treatment of helminthic infection. There was no association between dietary intake of indigenous greens and the socioeconomic indicators measured (age, type of employment, household size and land use score). Proximate composition, calcium, phosphorus, iron, potassium, magnesium, phylloquinone and total carotenes were determined for 13 species of indigenous greens. Composition of 5 of these has not been previously reported. Plasma phylloquinone was tested as a biochemical marker for validating determination of green plant intake.

Thesis (M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographical references.

Thesis (M.Sc.). / Written for the School of Dietetics and Human Nutrition. Title from title page of PDF (viewed 2008/07/30). Includes bibliographical references.

Thesis (M.Sc.(Plant Production and Soil Science))--University of Pretoria, 2007. / Abstract in English. Includes bibliographical references (leaves 179 - 194).

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Neste trabalho estudamos o problema da segregação de impurezas substitucionais em sistemas nanoestruturados metálicos formados pela justaposição de camadas (multicamadas). Utilizamos o modelo de ligações fortes (tight-binding) com um orbital por sítio para calcular a estrutura eletrônica desses sistemas, considerando a rede cristalina cubica simples em duas direções de crescimento: (001) e (011). Devido à perda de simetria do sistema, escrevemos o hamiltoniano em termos de um vetor de onda k, paralelo ao plano, e um &#305;ndice l que denota um plano arbitrario do sistema. Primeiramente, calculamos a estrutura eletrônica do sistema considerando-o formado por átomos do tipo A e, posteriormente, investigamos as modificações nessa estrutura eletrônica ao introduzirmos uma impureza do tipo B em um plano arbitrário do sistema. Calculamos o potencial introduzido por esta impureza levando-se em conta a neutralidade de carga através da regra de soma de Friedel. Calculamos a variação da energia eletrônica total &#916;El como função da posição da impureza. Como substrato, consideramos sistemas com ocupações iguais a 0.94 e 0.54 elétrons por banda, o que dentro do modelo nos permite chamá-los de Nie Cr. As impurezas sao tambem metais de transição - Mn, Fee Co. Em todos os casos investigados, foi verificado que a variação de energia eletrônica total apresenta um comportamento oscilatorio em função da posição da impureza no sistema, desde o plano superficial, até vários planos interiores do sistema. Como resultado, verificamos a ocorrencia de planos mais favoráveis à localização da impureza. Ao considerarmos um número relativamente grande de planos, um caso em particular foi destacado pelo aparecimento de um batimentono comportamento oscilatório de &#916;El. Estudamos também o comportamento da variação da energia total, quando camadas (filmes) são crescidas sobre o substrato e uma impureza do mesmo tipo das camadas é colocada no substrato. Levamos em conta a diferença de tamanho entre os átomos do substrato e os átomos dos filmes. Analisamos ainda a influência da temperatura sobre o comportamento oscilatório da energia total, considerando a expansão de Sommerfeld. / In this work we study the problem of substitutional impurity segregation in metallic nanostructured systems consisting of juxtaposition of layers (multilayer). Using a single band tight-binding model we calculate the electronic structure of these systems, considering a simple cubic lattice in two growth directions: (001) and (011). Due to the loss of symmetry of the system, the Hamiltonian is written as a function of a wave vector k parallel to the plane, and an index l which denotes an arbitrary plane of the system. Firstly, we calculate the electronic structure of the system with atoms of type A and investigate the changes in the electronic structure when an impurity of type B is introduced in an arbitrary plane of the system. We calculate the potential introduced by this impurity taking into account the charge neutrality through the Friedel sum rule. We also calculate the total electronic energy variation &#916;El as a function of the impurity position. As a substrate we consider systems with occupations equal to 0.94 and 0.54 per band, simulating Niand Crsystems in our model. The impurities are also transition metals - Mn, Feand Co. In all investigated cases, it was verified that the variation of the total electronic energy presents an oscillatory behavior that depends on the position in which the impurity is placed, from the surface plane up to several inner planes of the system. As a result, in all cases it has been verified the occurrence of more favorable planes to the location of impurity. When considering a relatively large number of planes, one case in particular drew attention by a remarkable beatingon the oscillatory behavior of &#916;El. We also study the behavior of the total electronic energy variation, when layers (films) are grown up on the substrate and an impurity of the same type of the layers is placed in the substrate. In our model calculation, a difference between the size of the atoms of the substrate and the film is taken into account. We also investigate the influence of temperature on the total electronic energy oscillatory behavior, considering the Sommerfeld expansion.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Neste trabalho estudamos o problema da segregação de impurezas substitucionais em sistemas nanoestruturados metálicos formados pela justaposição de camadas (multicamadas). Utilizamos o modelo de ligações fortes (tight-binding) com um orbital por sítio para calcular a estrutura eletrônica desses sistemas, considerando a rede cristalina cubica simples em duas direções de crescimento: (001) e (011). Devido à perda de simetria do sistema, escrevemos o hamiltoniano em termos de um vetor de onda k, paralelo ao plano, e um &#305;ndice l que denota um plano arbitrario do sistema. Primeiramente, calculamos a estrutura eletrônica do sistema considerando-o formado por átomos do tipo A e, posteriormente, investigamos as modificações nessa estrutura eletrônica ao introduzirmos uma impureza do tipo B em um plano arbitrário do sistema. Calculamos o potencial introduzido por esta impureza levando-se em conta a neutralidade de carga através da regra de soma de Friedel. Calculamos a variação da energia eletrônica total &#916;El como função da posição da impureza. Como substrato, consideramos sistemas com ocupações iguais a 0.94 e 0.54 elétrons por banda, o que dentro do modelo nos permite chamá-los de Nie Cr. As impurezas sao tambem metais de transição - Mn, Fee Co. Em todos os casos investigados, foi verificado que a variação de energia eletrônica total apresenta um comportamento oscilatorio em função da posição da impureza no sistema, desde o plano superficial, até vários planos interiores do sistema. Como resultado, verificamos a ocorrencia de planos mais favoráveis à localização da impureza. Ao considerarmos um número relativamente grande de planos, um caso em particular foi destacado pelo aparecimento de um batimentono comportamento oscilatório de &#916;El. Estudamos também o comportamento da variação da energia total, quando camadas (filmes) são crescidas sobre o substrato e uma impureza do mesmo tipo das camadas é colocada no substrato. Levamos em conta a diferença de tamanho entre os átomos do substrato e os átomos dos filmes. Analisamos ainda a influência da temperatura sobre o comportamento oscilatório da energia total, considerando a expansão de Sommerfeld. / In this work we study the problem of substitutional impurity segregation in metallic nanostructured systems consisting of juxtaposition of layers (multilayer). Using a single band tight-binding model we calculate the electronic structure of these systems, considering a simple cubic lattice in two growth directions: (001) and (011). Due to the loss of symmetry of the system, the Hamiltonian is written as a function of a wave vector k parallel to the plane, and an index l which denotes an arbitrary plane of the system. Firstly, we calculate the electronic structure of the system with atoms of type A and investigate the changes in the electronic structure when an impurity of type B is introduced in an arbitrary plane of the system. We calculate the potential introduced by this impurity taking into account the charge neutrality through the Friedel sum rule. We also calculate the total electronic energy variation &#916;El as a function of the impurity position. As a substrate we consider systems with occupations equal to 0.94 and 0.54 per band, simulating Niand Crsystems in our model. The impurities are also transition metals - Mn, Feand Co. In all investigated cases, it was verified that the variation of the total electronic energy presents an oscillatory behavior that depends on the position in which the impurity is placed, from the surface plane up to several inner planes of the system. As a result, in all cases it has been verified the occurrence of more favorable planes to the location of impurity. When considering a relatively large number of planes, one case in particular drew attention by a remarkable beatingon the oscillatory behavior of &#916;El. We also study the behavior of the total electronic energy variation, when layers (films) are grown up on the substrate and an impurity of the same type of the layers is placed in the substrate. In our model calculation, a difference between the size of the atoms of the substrate and the film is taken into account. We also investigate the influence of temperature on the total electronic energy oscillatory behavior, considering the Sommerfeld expansion.

This study used cross-sectional survey data to estimate farmers` perceptions of, and commonly cultivated ILVs, factors that influence the participation of smallholder famers in the production of Indigenous Leafy Vegetables and its contribution to household food security]. With regard to farmers` perceptions of ILVs, descriptive results reveal that a majority of the people from the study area share positive perceptions with respect to ILVs. Regression estimates for determinants of participation indicate that the production of ILVs is primarily conditioned by shared perceptions and institutional factors rather than the socio-economic attributes of farmers. Public policies that address the institutional framework (extension, credit, market and social networks) in favour of ILVs are more likely to promote production. Also, more research on the documentation and benefits of ILVs, supported by investments targeting educational campaigns towards promoting positive attitudes and dispelling fears and myths surrounding ILVs, will further promote production. With reference to the contribution of ILVs to food security, descriptive results indicate that participation in the production of ILVs leads to a higher HDDS and a lower HFIAS. Regression estimates further revealed that participation positively contributes to a higher HDDS and a lower HFIAS, suggesting that households who participate in the production of ILVs are more likely to be food secure than non-participants. Therefore, participation in the production of ILVs has significant potential to address household food security.

Thesis(M.Sc.(Agriculture Horticulture)) -- University of Limpopo, 2019 / Innovative methods of preserving the quality of traditionally processed green leafy vegetables are underway in Africa. Improvement of processing and preservation methods of leafy vegetables is another way of overcoming perishability restrictions and guaranteeing continued quality food supply in rural areas. The objectives of this study were: to determine the effect of time-based oven-drying on (1) mineral composition, (2) proximate composition and (3) microbial profiling of cowpea (Vigna unguiculata). Separate experiments were conducted for raw and cooked cowpea leaves with four treatments, viz 0 (sun dried), 24, 48 and 72 hours of oven-drying, arranged in a randomised complete block design with 5 replications. In raw cowpea leaves, relative to control (sun-drying), oven-drying period 48hrs, significantly decreased Potassium (K), Manganese (Mn), and Sodium (Na) content in raw cowpea leaves by 6, 9 and 13%, respectively. Similarly, oven-drying period 72hrs significantly decreased Ca, Fe, Mg, Zn, P and S by 5, 11, 16, 18 and 57%, respectively. In cooked cowpea leaves, relative to control (sun-drying), oven-drying period 24hrs significantly increased Na by 18%. Similarly 48hrs oven-drying periods increased Fe and K by 6 and 8%, respectively. Similarly, oven-drying period 72hrs significantly increased Ca, Mg and Mn by 8, 8 and 3%, respectively. In contrast, oven-drying period 72hrs significantly reduced Zn, P and S by 16, 10 and 39%, respectively. Relative to control (sun-drying), oven-drying period 24hrs significantly increased fat by 46% in raw cowpea leaves, however oven-drying period 72hrs significantly decreased protein, moisture, ash, fibre and carbohydrate by 10, 29, 18, 0.5, and 7% respectively. In contrast, relative to control (sun-drying), 72hrs increased energy by 3%. In cooked cowpea leaves, relative to control (sun-drying), ovendrying period 24hrs significantly increased energy by 1%. In contrast, relative to control (sun-drying) 72hrs oven-drying period decreased energy by 1%. Similarly, oven-drying 72hrs significantly decreased protein, moisture, ash, fat, fibre and carbohydrate by 8, 14, 13, 19, 0.4 and 10% respectively. Relative to control (sun-drying), oven-drying periods 24hrs significantly increased Staphylococcus spp. in raw cowpea leaves by 6%, respectively. Relative to control (sun-drying) 72hrs oven-drying period significantly decreased Shigella spp. by 92%, respectively. In cooked leaves, relative to control (sundrying), 72hrs drying periods decreased both Shigella spp. and Staphylococcus spp. by 99 and 21%, respectively. Total coliforms unit of Salmonella spp, Escherichia coli, Pseudomonas spp, and Bacillus cereus were absent and/or at an undetectable level according to the Tempo Biomerieux system results. In conclusion, cooked leaves retained most essential mineral elements as compared to raw when subjected to 72hrs of ovendrying as there was an improvement in the concentration of Ca, Fe, K, Mg, Mn and Na. However, in both raw and cooked cowpea leaves proximate composition was negatively affected as there was a decrease in protein content. Oven-drying period of 24 hours can be used to minimize the loss of protein. Cooked cowpea leaves subjected to 72hrs of oven-drying had least total coliforms for both Shigella spp and Staphylococcus spp, therefore have potential to serve as an alternative to sun-drying to reduce microorganism causing spoilage in leafy vegetables. Drying raw cowpea leaves under oven-drying periods less than 72 hours should be avoided as it reduces the mineral concentration and increase microbial count of microorganisms responsible for spoilage / National Research Foundation (NRF)

No description available.

High-profile outbreaks in the U.S. have been increasingly linked to the consumption of leafy greens (Xue et al. 2007), making traceability an important issue (Corkery and Popper 2018). Consumers' increasing attention to traceability (Hansstein 2014) has led to the implementation of blockchain-based traceability systems. This study measures U.S. consumers' willingness-to-pay (WTP) for blockchain-based traceability information in packages of romaine lettuce and spinach. We conduct two online Discrete Choice Experiments (DCEs) and surveys to understand consumer preferences for USDA-certified organic leafy greens, access to blockchain-based traceability information via QR codes, and the FDA's voluntary labeling guidelines involving growing region information. Our findings suggest that some U.S. consumers are willing to pay a premium for food products with blockchain-based traceability or standard traceability information delivered via QR-codes. Findings also reflect some consumers' interest in organic products, and in knowing the detailed growing region information, particularly if leafy greens are grown in Arizona.