Comparison in the aplication of the exploitation by optimal head model to hydroelectronic power station in run-of-the-river systems equipped with different types of turbines

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Aspectos clínicos y terapéuticos de las Trombosis Venosas y Arteriales

La integridad del endotelio vascular desempeña un papel crucial en el mantenimiento de la fluidez sanguínea al igual que las sustancias expresadas y liberadas por las células endoteliales y sus membranas. La trombosis venosa y arterial son trastornos comunes, potencialmente letales y afectan por igual a todas las etnias. Estos padecimientos aumentan progresivamente con la edad y se tornan comunes en pacientes hospitalizados. La heparina a bajas dosis se emplea como medida profiláctica de la Trombosis Venosa Profunda (TVP), y a dosis altas se utiliza cuando la patología implica un riesgo trombótico mayor, ya sea arterial o venoso; las Heparinas de Bajo Peso Molecular (HBPM) son ideales para la prevención de TVP. Los anticoagulantes orales constituyen agentes muy importantes en el arsenal terapéutico contra los fenómenos trombóticos, independientemente de su etiología. La Aspirina es el agente más estudiado y usado de los antiagregantes plaquetarios; se ha utilizado en el control y evaluación de otros agentes antiplaquetarios como ticlopidina, clopidogrel, aspirina más dipiridamol de liberación prolongada, actualmente recomendados. Como alternativa y para evitar la trombocitopenia inducida por la heparina, tenemos en estudio los inhibidores de la trombina y se esperan resultados alentadores. En relación con el tratamiento trombolítico, éste se debe instaurar en las primeras horas después de realizado el diagnóstico, teniendo en cuenta sus indicaciones y contraindicaciones, siendo cuidadosos al escoger el agente y que éste sea manejado por manos expertas, en centros adecuados y en aquellos casos que así lo ameriten; siempre debe tenerse presente el riesgo de hemorragia como efecto adverso con el uso de cualquiera de estos agentes.ABSTRACTThe integrity of the vascular endothelium is of primary importance for the maintenance of blood fluidity as well as the substances expressed and released by endothelial cells and membranes. Venous and arterial thrombosis are common diseases potentially fatal affecting equally to all races. These ailments are more frequent with increasing age and there are common in hospitalized patients. Heparin at low dosage is being used as preventive for Deep Vein Thrombosis (DVT); higher doses are given in pathologies with a higher risk of venous or arterial thrombosis; Low Molecular Weight Heparins (LMWH) are ideal for prevention of DVT. Oral anticoagulants are a very important therapeutic group against events of thrombosis regardless of ethiology. Aspirin has been the most studied and used molecule to prevent platelet aggregation; actually is recommended at low doses and as been compared with other products used at present for the prevention of platelet aggregation such as ticlopidin, clopidrogrel and slow liberation of aspirin combined with dipiridamol. To overcome the heparin-induced thrombocytopenia there are being tryed thrombin inhibitors with great hope in good results. As for the thrombolytic treatment itself, it should be initiated during the first hours of diagnosis keeping in mind indications and counterindications, being very careful in the choice of the agent, used by experts, in those cases where necessary and in patients in hospitals with facilities for adequate control. It should also be kept in mind the risk of hemorrhage as side effect in the therapeutic with these agents

Passivity-Based Control: An Approach to Regulate Nonlinear Chemical Processes

This paper presents the development of a Passivity-Based Controller (PBCr) from a First-Order-Plus-Dead-Time model of the process. This approach results in a fixed structure controller that depends on the characteristic parameters of the model. This allows a unique controller of adjustable parameters that can be used in several processes. Computer simulations on a nonlinear chemical process judge the controller performance. The simulation results showed effectiveness and good performance for the studied case