RESUMEN
BACKGROUND: In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated. METHODS: The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species. RESULTS: Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed. CONCLUSION: Marine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3) was detected.
Asunto(s)
Ácidos Grasos Insaturados/análisis , Algas Marinas/química , Clima Tropical , Acilación , Océano Atlántico , Vías Biosintéticas , Ácidos Grasos Insaturados/biosíntesis , Cromatografía de Gases y Espectrometría de Masas , Especificidad de la EspecieRESUMEN
Bio-economic farm models are tools to evaluate ex-post or to assess ex-ante the impact of policy and technology change on agriculture, economics and environment. Recently, various BEFMs have been developed, often for one purpose or location, but hardly any of these models are re-used later for other purposes or locations. The Farm System Simulator (FSSIM) provides a generic framework enabling the application of BEFMs under various situations and for different purposes (generating supply response functions and detailed regional or farm type assessments). FSSIM is set up as a component-based framework with components representing farmer objectives, risk, calibration, policies, current activities, alternative activities and different types of activities (e.g., annual and perennial cropping and livestock). The generic nature of FSSIM is evaluated using five criteria by examining its applications. FSSIM has been applied for different climate zones and soil types (criterion 1) and to a range of different farm types (criterion 2) with different specializations, intensities and sizes. In most applications FSSIM has been used to assess the effects of policy changes and in two applications to assess the impact of technological innovations (criterion 3). In the various applications, different data sources, level of detail (e.g., criterion 4) and model configurations have been used. FSSIM has been linked to an economic and several biophysical models (criterion 5). The model is available for applications to other conditions and research issues, and it is open to be further tested and to be extended with new components, indicators or linkages to other models.
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Agricultura/economía , Modelos Biológicos , Modelos Económicos , Agricultura/métodos , Conservación de los Recursos Naturales , Ambiente , Política AmbientalRESUMEN
Numerous agro-environmental indicators have been developed by agronomists and ecologists during the last 20 years to assess the environmental impact of farmers' practices, and to monitor effects of agro-environmental policies. The objectives of this paper were (i) to measure the accuracy of a wide range of agro-environmental indicators from experimental data and (ii) to discuss the value of different information typically used by these indicators, i.e. information on farmers' practices, and on plant and soil characteristics. Four series of indicators were considered in this paper: indicators of habitat quality for grassland bird species, indicators of risk of disease in oilseed rape crops, indicators of risk of pollution by nitrogen fertilizer, and indicators of weed infestation. Several datasets were used to measure their accuracy in cultivated plots and in grasslands. The sensitivity, specificity, and probability of correctly ranking plots were estimated for each indicator. Our results showed that the indicators had widely varying levels of accuracy. Some show very poor performance and had no discriminatory ability. Other indicators were informative and performed better than random decisions. Among the tested indicators, the best ones were those using information on plant characteristics such as grass height, fraction of diseased flowers, or crop yield. The statistical method applied in this paper could support researchers, farm advisers, and decision makers in comparing various indicators.
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Agricultura , Conservación de los Recursos Naturales , Ambiente , Monitoreo del Ambiente/métodos , Agricultura/estadística & datos numéricos , Animales , Área Bajo la Curva , Aves , Brassica napus , Ecosistema , Fertilizantes , Funciones de Verosimilitud , Nitrógeno , Enfermedades de las Plantas , Plantas , Curva ROC , Contaminación Química del AguaRESUMEN
In a sowing by stages test with winter wheat variety Jingdong 8 (JD8) as reference, this paper studied the photothermal characteristics of a non-photosensitive and extra- premature winter wheat variety Dongzao 5 (DZ5), and the effects of sowing stages on its growth and yield. The results showed that the harvest date of DZ5 was 4-5 days earlier than that of JD8, and its yield with standard sowing date increased by 43.4%. In addition, DZ5 had a shorter thermoperiod for ear differentiation, and didn't need strict vernalization process and photoperiod, which could be sown either before or after winter.
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Fotosíntesis/fisiología , Triticum/clasificación , Fotoquímica , Estaciones del Año , TemperaturaRESUMEN
Este estudio evaluó sistemas de cultivo de Iguana iguana (iguana verde) en Nicaragua, Costa Rica y Panamá. Los datos fueron acopiados en 1997, a través de entrevistas a cultivadores de iguana, sus vecinos, expertos en iguana y funcionarios gubernamentales acerca de los beneficios socieconómicos y ecológicos del cultivo de iguanas. Se esperaba que este cultivo proveería ingresos adicionales, estimularía la conservación de la naturaleza y la producción de proteína animal, y aumentaría el número de árboles y el conocimiento acerca de la naturaleza. Una limitación mayor fue la inversión inicial, en especial porque los bancos no contemplan programas crediticios y los pequeños productores dependían de esquemas crediticios de ONGs. En nicaragua y Panamá, los sistemas de cultivo de iguana existentes tenían pocas perspectivas de generar ingresos adicionales. El cultivo de iguanas tuvo beneficios ecológicos al estimular actitudes de conservación de la naturaleza y los árboles, aumentó el conocimiento de la naturaleza de los campesinos, y se basó en alimentos locales. La legislación existente y las regulaciones del cultivo y comercio de iguanas limitaron las posibilidades de comercialización de iguanas y sus productos. La mayoría de los sistemas de cultivo de iguana no generaron ingresos adicionales, tuvieron altos costos iniciales y necesitaron de ayuda profesional para cumplir con los requisitos formales. Para introducir exitosamente el cultivo de iguana, éste debe resultar en ganancias para los campesinos, quienes deben recibir ayuda profesional para cumplir los requisitos formales para el cultivo de iguana