575 research outputs found

    Soil and water pollution in a banana production region in tropical Mexico

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    The effects of abundant Mancozeb (Mn, Zn— bisdithiocarbamate) applications (2.5 kg ha-1week-1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the main metabolite ethylenethiourea was near the detection limit. Surface and subsurface water was highly polluted with ethylenethiourea, the main metabolite of Mancozeb (22.5 and 4.3 lg L-1, respectively), but not with manganese. In deep ground water, no ethylenethiourea was detected. The level of pollution in the region presents a worrisome risk for aquatic life and for human health

    Ovarian maturation and haemolymphatic vitellogenin concentration of Pacific white shrimp <i>Litopenaeus vannamei</i> (Boone) fed increasing levels of total dietary lipids and HUFA

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    Two experiments were carried out to determine the quantitative lipid requirements for ovarian maturation of Litopenaeus vannamei (Boone) broodstock. The first experiment tested the effect of total dietary lipid (TDL) levels of 8.1%, 8.8%, 9.8% and 11.2% on the gonadosomatic index (GSI), hepatosomatic index (HSI), survival and body weight. The second experiment tested the effect of total dietary levels of highly unsaturated fatty acids (TDH) 0.6%, 1.3%, 2.0% and 2.7% on the same parameters mentioned above and on the haemolymphatic vitellogenin (vg) concentration. The GSI was higher in females fed 8.1% TDL as compared with those fed 8.8% TDL (P=0.05), and higher in females fed 8.1% and 8.8% TDL than in those fed 9.8% and 11.2% TDL. lncreasing TDH levels led to increasing levels of highly unsaturated fatty acids (HUFA) in the ovaries (r² = 0.999). However, the GSI was not affected by dietary treatments (P > 0.05). The vg concentration was higher in animals receiving 2.0% TDH as compared with those receiving 2.7% TDH. In conclusion, high TDL levels affected ovarian maturation in a negative way, why TDH levels had no pronounced effect on ovarian maturation within the range tested in this study

    Quinoa (Chenopodium Quinoa Willd), from Nutritional Value to Potential Health Benefits: An Integrative Review

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    Chenopodium quinoa Willd, known as quinoa, has been cultivated and consumed by humans for the last 5,000-7,000 years. Quinoa was important to pre-Columbian Andean civilizations, as the Incas considered it a gift from their gods. Quinoa has potential health benefits and exceptional nutritional value: a high concentration of protein (all essential amino acids highly bioavailable), unsaturated fatty acids, a low glycemic index; vitamins, minerals and other beneficial compounds; it is also gluten-free; furthermore, quinoa is a sustainable food, as plants exhibit a carbon and water food print that is between 30 and 60 times lower than that of beef. Quinoa is easy to cook, has versatility in preparation, and could be cultivated in different environments. For these reasons, quinoa, previously considered a food of low social prestige, is now the focus of attention of many countries worldwide. However, few studies exist on quinoa or quinoa compounds, in vitro, in vivo and clinical trials, for assessing its potential clinical applications supported by strong scientific evidence; thus, there is a need for well-designed clinical trials and increased scientific research in this field

    Water, Food, and Irrigation

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    Irrigated agriculture plays a central role in global food production as it provides resilience to rainfall variability, increased productivity and production security. However, it has also gone hand in hand with serious socio-environmental challenges. Large-scale irrigated agricultural production, which depends on both surface and groundwater resources, has encountered several technical and managerial challenges. It has led to widespread environmental deterioration through drying and polluting rivers, lakes, wetlands, and aquifers. At the same time, irrigated agricultural production has been increasingly commodified, specialized and globalized through large commercial farming enterprises, contract farming and international agro-export chains. This has led to widespread processes of land and water accumulation and related socio-environmental inequities in many regions of the world. In contraposition to this tendency peasant irrigated production plays a key role in producing for local and regional fresh food markets. In this context, we explore a few innovative and promising grassroots initiatives that spring from peasant agriculture. These are agro-ecology, farmer-led irrigation development and peri-urban agriculture, all initiatives that rest on the creation of local food production and marketing networks. Finally, this book chapter closes by setting out critical questions about policies and the political implications of food consumption patterns

    Discrete Dynamic Model for The Evaluation of Performance and Components of Organizational Behavior

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    For an organization the study of behavioral factors such as performance, which can come to depend on human vigilance, family problems, communication, motivation and stress are independent factors. This research paper analyzes the relationships of performance factors by applying mathematical models that eliminate subjectivity in the evaluation process. To this end, we proceed with statistical studies that confirm the relationships between the components and study variables that allow us to define a model through multiple linear regression. The results confirm the existence of strong relationships between independent factors and performance, also a factor of 48.5% acceptance of the model
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