180 research outputs found

    Análisis agroclimático de la región de la Mojana :informe final

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    El área de La Mojana presenta una forma de elipse donde el eje mayor de la región tiene una longitud de 119.5 km aproximadamente, con dirección norte sur y el eje menor es perpendicular, con 71.5 km, es una zona plana baja, donde se ubican los conos deltáicos de los río Cauca y Magdalena y San Jorge, cuyas características geomorfológicas han generado gran cantidad de ciénagas y pantanos sujetos continuamente a inundaciones dadas por los altos niveles de los río durante períodos invernales. Estas zonas de inundación son elementos de amortiguación temporal de las crecientes de los ríos Cauca, San Jorge y Brazo de Loba, y de acumulación y depositación de sedimentos transportados por éstos. La región constituye entonces un importante sistema regulador de las corrientes fluviales, a la vez un sistema fuertemente deteriorado por la intensa acumulación de sedimentos y contaminantes provenientes de sus cuencas tributarias. En consecuencia este, deterioro del sistema debe mitigarse mediante acciones que propendan por la recuperación y preservación de los ecosistemas y por el desarrollo sostenible de actividades productivas. (Mehestre, A. et al, 1997)

    Accumulation of scandium in plasma in patients with chronic renal failure

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    Scandium (Sc) is an element with many industrial applications, but relatively little is known about its physiological and/or toxicological effects, and very little data are available concerning the role of Sc in chronic renal failure (CRF). This paper examines the changes in plasma levels of Sc in predialysis patients with CRF and the relationship with blood parameters. The participants in this trial were 48 patients with CRF in predialysis and 53 healthy controls. Erythrocyte, haemoglobin, and haematocrit counts in blood were determined, and levels of creatinine, urea, uric acid, albumin, total protein and Sc were measured in plasma. The glomerular filtration rate (GFR) was calculated using the Cockcroft-Gault index. The CRF patients were found to have higher plasma levels of creatinine, urea, uric acid, albumin, total protein, and Sc and a lower GFR than that the controls. Scandium in plasma was positively correlated with creatinine and plasma urea and negatively correlated with GFR, haemoglobin, and haematocrit and was associated with the risk of lower levels of erythrocytes, haemoglobin, and haematocrit. CRF was associated with increases in the circulating levels of scandium.This research was supported by Plan Nacional I+D Project 1FD 1997-0642

    Changes in iron metabolism and oxidative status in STZ-induced diabetic rats treated with bis(maltolato) oxovanadium(IV) as an antidiabetic agent

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    The role of vanadium as a micronutrient and hypoglycaemic agent has yet to be fully clarified. The present study was undertaken to investigate changes in the metabolism of iron and in antioxidant defences of diabetic STZ rats following treatment with vanadium. Four groups were examined: control; diabetic; diabetic treated with 1 mgV/day; and Diabetic treated with 3 mgV/day. The vanadium was supplied in drinking water as bis(maltolato) oxovanadium (IV) (BMOV). The experiment had a duration of five weeks. Iron was measured in food, faeces, urine, serum, muscle, kidney, liver, spleen, and femur. Superoxide dismutase, catalase, NAD(P)H: quinone-oxidoreductase-1 (NQO1) activity, and protein carbonyl group levels in the liver were determined. In the diabetic rats, higher levels of Fe absorbed, Fe content in kidney, muscle, and femur, and NQO1 activity were recorded, together with decreased catalase activity, in comparison with the control rats. In the rats treated with 3 mgV/day, there was a significant decrease in fasting glycaemia, Fe content in the liver, spleen, and heart, catalase activity, and levels of protein carbonyl groups in comparison with the diabetic group. In conclusion BMOV was a dose-dependent hypoglycaemic agent. Treatment with 3 mgV/day provoked increased Fe deposits in the tissues, which promoted a protein oxidative damage in the liver.The authors are grateful for support received from the Consejería de Innovación, Ciencia y Empresa, Andalusian Regional Government (Project P06-CTS-01435)

    Cacao Pod Husk Flour as an Ingredient for Reformulating Frankfurters: Effects on Quality Properties

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    The cocoa pod husk is considered a source of dietary fiber with a high content of water-soluble pectins, bioactive compounds which should be viewed as a by-product with the potential to be incorporated into food. This study aimed to investigate the effect of adding different cocoa pod husk flour (CPHF) levels as a starch replacement for reformulating frankfurters. Results showed that the addition of 1.5 and 3.0% pod husk proportionally increased the frankfurter's fiber content by 0.49 ± 0.08 and 0.96 ± 0.19 g/100 g, which is acceptable for a product that does not contain fiber. Textural properties and sensory characteristics were affected when substituting the starch with CPHF, either totally or partially, although these samples had higher water content, hardness, and adhesiveness while springiness decreased. Non-adverse effects of nitrite on polyphenolic compounds content were evidenced in samples enriched with CPHF. The incorporation of CPHF did not significantly affect the color parameters (DeltaE < 3). Finally, the panelists indicated a sensation of the unsalted sausage, suggesting that CPHF may have natural mucoadhesion properties. In conclusion, in formulated meat products such as sausages, plant co-products such as cacao pod husks could be a valid new ingredient to improve technological parameters, functional characteristics, and stability

    Free-form Fresnel RXI-RR Köhler design for high-concentration photovoltaics with spectrum-splitting

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    Development of a novel HCPV nonimaging concentrator with high concentration (>500x) and built-in spectrum splitting concept is presented. It uses the combination of a commercial concentration GaInP/GaInAs/Ge 3J cell and a concentration Back-Point-Contact (BPC) silicon cell for efficient spectral utilization, and external confinement techniques for recovering the 3J cell's reflection. The primary optical element (POE) is a flat Fresnel lens and the secondary optical element (SOE) is a free-form RXI-type concentrator with a band-pass filter embedded in it - Both the POE and SOE performing Köhler integration to produce light homogenization on the receiver. The band-pass filter transmits the IR photons in the 900-1200 nm band to the silicon cell. A design target of an "equivalent" cell efficiency ~46% is predicted using commercial 39% 3J and 26% Si cells. A projected CPV module efficiency of greater than 38% is achievable at a concentration level larger than 500X with a wide acceptance angle of ±1°. A first proof-of concept receiver prototype has been manufactured using a simpler optical architecture (with a lower concentration, ~100x and lower simulated added efficiency), and experimental measurements have shown up to 39.8% 4J receiver efficiency using a 3J cell with a peak efficiency of 36.9%

    Freeform Fresnel RXI-RR Köhler design with spectrum-splitting for photovoltaics

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    The development of a novel optical design for the high concentration photovoltaics (HPCV) nonimaging concentrator (>500x) that utilizes a built-in spectrum splitting concept is presented. The primary optical element (POE) is a flat Fresnel lens and the secondary optical element (SOE) is a free-form RXI-type concentrator with a band-pass filter embedded in it. The POE and SOE perform Köhler integration to produce light homogenization on the receiver. The system uses a combination of a commercial concentration GaInP/GaInAs/Ge 3J cell and a concentration Back-PointContact (BPC) silicon cell for efficient spectral utilization, and an external confinement technique for recovering the 3J cell’s reflection. A design target of an “equivalent” cell efficiency ~46% is predicted using commercial 39% 3J and 26% Si cells. A projected CPV module efficiency of greater than 38% is achievable at a concentration level greater than 500X with a wide acceptance angle of ±1º. A first proof-of concept receiver prototype has been manufactured using a simpler optical architecture (with a lower concentration, ~100x and lower simulated added efficiency), and experimental measurements have shown up to 39.8% 4J receiver efficiency using a 3J cell with a peak efficiency of 36.9

    Ultra-High Efficiency, High-Concentration PV System Based On Spectral Division Between GaInP/GaInAs/Ge And BPC Silicon Cells

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    A novel HCPV nonimaging concentrator concept with high concentration (>500×) is presented. It uses the combination of a commercial concentration GaInP∕GaInAs∕Ge 3J cell and a concentration Back‐Point‐Contact (BPC) concentration silicon cell for efficient spectral utilization, and external confinement techniques for recovering the 3J cell′s reflection. The primary optical element (POE) is a flat Fresnel lens and the secondary optical element (SOE) is a free‐form RXI‐type concentrator with a band‐pass filter embedded it, both POE and SOE performing Köhler integration to produce light homogenization. The band‐pass filter sends the IR photons in the 900–1200 nm band to the silicon cell. Computer simulations predict that four‐terminal terminal designs could achieve ∼46% added cell efficiencies using commercial 39% 3J and 26% Si cells. A first proof‐of concept receiver prototype has been manufactured using a simpler optical architecture (with a lower concentration, ∼ 100× and lower simulated added efficiency), and experimental measurements have shown up to 39.8% 4J receiver efficiency using a 3J with peak efficiency of 36.9

    Entre la guerra y la paz: aproximaciones metodológicas al estudio de las mujeres y la guerra en el mundo antiguo

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    La aplicación de la metodología de género a la investigación sobre la guerra permite comprender la relación de las mujeres con la misma en las sociedades antiguas. Siendo el ejército y la guerra componentes esenciales de la identidad masculina, a la mujer queda reservado el papel de madre de soldados o víctima del conflicto. Cualquier otra forma de intervención femenina se considera desde ese punto de vista una inversión de los roles establecidos. Analizando los casos griego y romano, a través de las fuentes literarias e iconográficas – especialmente útiles para Roma – trataremos de caracterizar los diferentes papeles de las mujeres en la guerra: imagen de la paz, instigadoras de guerras, combatientes activas o colaboradoras directas, mediadoras, víctimas y beneficiarias del conflicto. Los modelos de relaciones de género oficialmente difundidos en las sociedades clásicas resultan no ser los únicos posibles.The application of gender methodology to war research provides an understanding of the relationship that women had with war in ancient societies. The army and war being one of the essential components of male gender identity, women are reserved the role of mother of soldiers or victims of the conflict. Any other form of female intervention is considered from this point of view as a reversal of established roles. Analyzing the Greek and Roman cases, through the literary and iconographic sources – especially useful for Rome – we will try to characterize the different roles of women in war: image of peace, instigators of wars, active combatants or direct collaborators, mediators, victims and beneficiaries of the conflict. The models of gender relations officially spread in classical societies are not the only possible ones

    Accumulation of Scandium in Plasma in Patients with Chronic Renal Failure

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    Scandium (Sc) is an element with many industrial applications, but relatively little is known about its physiological and/or toxicological effects, and very little data are available concerning the role of Sc in chronic renal failure (CRF). This paper examines the changes in plasma levels of Sc in predialysis patients with CRF and the relationship with blood parameters. The participants in this trial were 48 patients with CRF in predialysis and 53 healthy controls. Erythrocyte, haemoglobin, and haematocrit counts in blood were determined, and levels of creatinine, urea, uric acid, albumin, total protein and Sc were measured in plasma. The glomerular filtration rate (GFR) was calculated using the Cockcroft-Gault index. The CRF patients were found to have higher plasma levels of creatinine, urea, uric acid, albumin, total protein, and Sc and a lower GFR than that the controls. Scandium in plasma was positively correlated with creatinine and plasma urea and negatively correlated with GFR, haemoglobin, and haematocrit and was associated with the risk of lower levels of erythrocytes, haemoglobin, and haematocrit. CRF was associated with increases in the circulating levels of scandium
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