Consumption of food away from home (FAFH) is widely believed to be a contributing factor to the current obesity crisis and other diet related problems in North America. At present, in Canada, a number of issues related to FAFH consumption such as the relationship between obesity and fast foods, trans-fats, sugar and sodium content of restaurant foods, and restaurant advertising for children are being widely discussed. In these discussions, it is apparent that the interrelationships between FAFH, nutrition and diet related diseases are complex. Therefore, there are significant gaps in our knowledge. In this study, a number of important research questions related to FAFH consumption were studied in order to provide a detailed understanding of FAFH purchase trends, nutrient demand trends, factors affecting these trends and to provide some idea of the possible effectiveness of proposed policy interventions in the area. In paper one of this study, a sample of Canadian FAFH purchases were analysed using a two stage demand model to examine the impact of industry advertising, households habit forming preferences and socio-demographic and economic variables. Given the unique method of restaurant categorization, results provide new and additional information of the impact of above variables in Canadian context. The second study examined the demand for selected nutrients in FAFH to understand factors affecting nutrient intake in FAFH foods focusing on chain restaurants. An innovative measure of nutrient content (nutrient density) was used in the analysis and study results provides interesting new information about nutrient consumption from chain restaurants in the FAFH market. The third study examined how some specific food industry changes in product formulations aimed at reducing trans-fatty acids (TFAs) could and have affected consumers overall diet quality and their demand for food away from home. This study provides some indications of effectiveness of the current trans-fat recommendations in Canada. In summary, this study is an empirical investigation of a number of questions related to Canadian FAFH consumption: What is the structure of the FAFH market in Canada? What are the households FAFH purchasing patterns? What is the impact of advertising and habit forming preferences and socio-economic and demographic factors on FAFH purchases? What are the nutrition profiles of the most popular menu items of chain restaurants? What are the factors affecting nutrient demand in FAFH foods? Would a specific food industry change in product formulation such as reducing TFAs have affect consumers overall diet quality and their demand for FAFH? In general, results from the three independent studies provide useful information to fill some of the gaps in our knowledge of FAFH consumption, especially on health and nutrition with implications for public policy. / Agricultural and Resource Economics

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Autotrophs and heterotrophs differ in their demand, acquisition and use of materials, but fundamentally nutrient demand is inherently linked to metabolism based on the stoichiometry of biochemical reactions. The differences between these two groups of organisms confound straightforward regression approaches to quantifying the relationship between nutrient demand and metabolism at an ecosystem level. We address how nutrient demand in headwater streams changes with shifts in organic matter supply and associated microbial activity by investigating these relationships in the predominantly heterotrophic conditions of a southern Appalachian stream. We measured litter input, organic matter standing crops, litter respiration rates and nitrate demand several times during the course of decomposition. There was a strong relationship between leaf standing crop and nitrate uptake efficiency across dates with maximal efficiency occurring when litter standing crops were highest. There was also an increase in nitrogen (N) uptake rate relative to respiration rates as breakdown progressed, which appears to be due to a shift in nutrient supply from the substrate to the water column associated with the depletion of labile, high quality organic matter in the substrate. It is our contention that streams establish a gradient of resource supply from particulate to dissolved sources that coincides with the movement of materials from terrestrial to marine systems. / Master of Science

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O meloeiro à uma das cucurbitÃceas mais exigentes em relaÃÃo à adubaÃÃo, sendo necessÃrios conhecimentos de solo, exigÃncia nutricional e eficiÃncia na utilizaÃÃo de nutrientes, para uma adubaÃÃo adequada. Objetivou-se a parametrizaÃÃo de um sistema para recomendaÃÃo de corretivos e fertilizantes para a cultura do meloeiro (Ferticalc-MelÃo) com base no balanÃo nutricional. O sistema apresenta um mÃdulo para correÃÃo da acidez no solo utilizando dois mÃtodos de recomendaÃÃo de calagem. Para estimar a adubaÃÃo recomendada o sistema foi subdividido: subsistema requerimento (REQ), que contempla a demanda de nutrientes pela planta, considerando a eficiÃncia de recuperaÃÃo dos nutrientes aplicados, alÃm de uma dose que atende ao critÃrio de âsustentabilidadeâ apenas para o nutriente K, e o subsistema suprimento (SUP), que corresponde à oferta de nutrientes pelo solo e Ãgua de irrigaÃÃo. ApÃs a determinaÃÃo do REQtotal e SUPtotal, realizou-se o balanÃo nutricional, no qual em resultado positivo (REQ > SUP), recomenda-se a aplicaÃÃo de fertilizantes, e negativo ou nulo (REQ ≤ SUP), nÃo se recomenda aplicar. Foram feitas simulaÃÃes para quatro diferentes tipos de meloeiro: Amarelo, Cantaloupe, GÃlia e Pele-de-sapo, numa faixa de produtividade esperada total de 15.000 a 45.000 kg ha-1 considerando diferentes valores de P-rem. O sistema estimou que o GÃlia foi o menos exigente em P enquanto o Pele-de-sapo mostrou-se mais exigente. Dentre os tipos, o Cantaloupe foi menos exigente em N e Ca, enquanto o Amarelo exigiu menos K, Mg e S. Para os micronutrientes, o Amarelo foi o que menos exigiu Fe, Cu e Zn, enquanto Mn foi menos demandado pelo Cantaloupe. O suprimento dos nutrientes K, Ca e Mg pela Ãgua de irrigaÃÃo foram respectivamente, 23,40; 1.216,00 e 136,08 kg ha-1 para as condiÃÃes de solo (AS - I) e 6,24; 48,00 e 4,86 kg ha-1 para (AS-II). De maneira geral, o sistema recomendou adubaÃÃo com macronutrientes para (AS-II) com exceÃÃo para Mg e Ca, enquanto para (AS-I) foi recomendado apenas para N e P, em funÃÃo dos altos teores de K, Ca e Mg no solo e Ãgua de irrigaÃÃo. Comparando com outros mÃtodos o sistema mostrou-se mais dinÃmico e flexÃvel nas suas recomendaÃÃes. AtravÃs da anÃlise de sensibilidade do sistema, constatou que a variÃvel que mais influenciou as recomendaÃÃes foi a produtividade, seguida dos teores de nutriente no solo. O sistema apresentou resultados satisfatÃrios em relaÃÃo Ãs recomendaÃÃes, porÃm necessita ser avaliado sob condiÃÃes de campo para seu aperfeiÃoamento em futuras versÃes. / The melon is one of cucurbitaceae most demanding in relation to fertilization, being necessary knowledge of soil, nutritional requirements and nutrient use efficiency, for a proper fertilization. The objective was parameterization of a system for recommendation of fertilizers for the melon (Ferticalc-Melon) based on the nutrient balance. The system features a module for soil acidity correction using two methods of liming. To estimate the fertilizer recommended, the system was subdivided: requirement subsystem (REQ), which includes the demand for nutrients by the plant, whereas the efficiency of nutrient recovery, and a dose that meets the criterion of "sustainability" only for the nutrient K, and supply subsystem (SUP), which corresponds to the supply of nutrients from the soil and irrigation water. After determining the REQamount and SUPamount, held the nutritional balance, in which a positive result (REQ > SUP), it is recommended that the application of fertilizer, and negative or zero (REQ ≤ SUP), not recommended to apply. Simulations were made for four different types of melon: Amarelo, Cantaloupe, GÃlia e Pele-de-sapo, in the range of productivity expected total of 15,000 to 45,000 kg ha-1 considering different values of P-rem. The system estimated that the GÃlia was the least demanding in P while Pele-de-sapo was the most demanding. Among the types, Cantaloupe was the least demanding in N and Ca, while the Amarelo requires less K, Mg and S. For the micronutrients, Amarelo was the least demanded that Fe, Cu and Zn, whereas Mn was less demanded by Cantaloupe. The supply of nutrients K, Ca and Mg by irrigation water were respectively, 23.40; 1,216.00 e 136.08 kg ha-1 to soil conditions (AS - I) and 6.24; 48.00 and 4.86 kg ha-1 to (AS-II). In general, the system recommended fertilization with macronutrients for (AS-II) except for Mg and Ca, while for (AS-I) was recommended only N and P, due to high levels of K, Ca and Mg in the soil and irrigation water. Compared with other methods the system proved to be more dynamic and flexible in its recommendations. By analyzing the sensitivity of the system, found that the variable that most influenced the recommendations was the productivity, then the nutrient content in soil. The system showed good results in relation to the recommendations, but needs to be evaluated under field conditions for your improvement in future versions.