993 resultados para CANALIZACIÓN DE RÍOS


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This work describes the mechanism of action of some reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the oxidative stress of the human body, and their consequences on damage to DNA, RNA, proteins and lipids. It also illustrates the defense system of our organism against these ROS and RNS species. The action of nonenzymatic protection systems is reported, with emphasis on micromolecules like Q10 coenzyme, vitamin C, alpha-tocopherol, carotenoids and flavonoids. The importance of flavonoids is also emphasized, and their body protection mechanism is detailed.

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En febrero de 1813 la edificación del Convento de San Carlos Borromeo de San Lorenzo resguardó al cuerpo de granaderos al mando del coronel José de San Martín en su lucha contra el ejército español. Pero también fue el escenario en el que se produjo, en abril de 1819, el conocido "Armisticio de San Lorenzo" que se firmó entre representantes de las provincias de Buenos Aires, Santa Fe y Entre Ríos para acordar el cese de la hostilidad.

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The cost of reusing water in micro-irrigation at the field level has not been studied in depth although the use of effluents in agriculture is a viable alternative in areas where water is scarce or there is intense competition for its use. The aim of the present study is to analyse the private costs of water reuse in micro-irrigation in an experimental plot. This analysis is intended to provide information about the decision a farmer would make when the choice to use conventional or reclaimed water is guided by cost criteria. The components of the total costs of different combinations of four types of filters and five emitters that can be installed in micro-irrigation systems using reclaimed water have been studied with the data obtained from an experimental plot in conditions similar to those of fruit orchards. Different scenarios that compared the costs of using conventional or reclaimed water in terms of water price and nutrient content were also studied. The results show that a proper combination of filters and emitters can save up to 33% in irrigation costs. Capital costs and maintenance costs were the most variable among the different combinations. Scenario analysis showed that the greater price of reclaimed water could be compensated by high nutrient contents, which would reduce fertilizer costs

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A micellar electrokinetic chromatographic method (MEKC) is described for determining residues of amphenicols(chloramphenicol,thiamphenicol and florfenicol) in bovine milk. MEKC is conducted by using a separation buffer consisting of 20 mM Na2HPO4, 10 mM Na2B4O7, 50 mM SDS at pH 8.0; UV detection at 210 nm and 10 kV of voltage. The limit of detection ranged from 4.3-5.3 µg L-1. The MEKC method was applied for the simultaneous determination of amphenicols in milk samples spiked with amphenicols at three concentration levels: 10, 30 and 50 µg L-1. Recoveries ranging from 91-105% were obtained by following a simple extraction/preconcentration procedure.

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The generation of reactive oxygen species (ROS) may be both beneficial to cells, performing functions in intracellular signaling and detrimental, modifying cellular biomolecules. ROS can cause DNA damage, such as base damage and strand breaks. Organisms respond to chromosome insults by activation of a complex and hierarchical DNA-damage response pathway. The extent of DNA damages determines cell fate: cell cycle arrest and DNA repair or cell death. The ATM is a central protein in the response to DNA double-strand breaks by acting as a transducer protein. Collected evidences suggest that ATM is also involved in the response to oxidative DNA damage.

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The generation of reactive oxygen and nitrogen species (ROS and RNS) during metabolism is capable of damaging cellular biomolecules. To be protected against oxidative injury, cells evolved complex cellular defense mechanisms and the capability to use exogenous antioxidants to eliminate ROS/RNS. The potential role of micronutrients as antioxidants (vitamin C, vitamin E, carotenoids and poliphenols) has stimulated intense research efforts. In various human supplementation studies, however, these compounds presented pro-oxidant effects at high doses for most risk groups. Therefore, more studies about the bioavailability, tissue uptake, metabolism and biological activities should be performed before establishing recommendations for disease prevention.

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Lipid overload in obesity and type 2 diabetes is associated with adipocyte dysfunction, inflammation, macrophage infiltration, and decreased fatty acid oxidation (FAO). Here, we report that the expression of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme in mitochondrial FAO, is higher in human adipose tissue macrophages than in adipocytes and that it is differentially expressed in visceral vs. subcutaneous adipose tissue in both an obese and a type 2 diabetes cohort. These observations led us to further investigate the potential role of CPT1A in adipocytes and macrophages. We expressed CPT1AM, a permanently active mutant form of CPT1A, in 3T3-L1 CARΔ1 adipocytes and RAW 264.7 macrophages through adenoviral infection. Enhanced FAO in palmitate-incubated adipocytes and macrophages reduced triglyceride content and inflammation, improved insulin sensitivity in adipocytes, and reduced endoplasmic reticulum stress and ROS damage in macrophages. We conclude that increasing FAO in adipocytes and macrophages improves palmitate-induced derangements. This indicates that enhancing FAO in metabolically relevant cells such as adipocytes and macrophages may be a promising strategy for the treatment of chronic inflammatory pathologies such as obesity and type 2 diabetes.

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Lipid overload in obesity and type 2 diabetes is associated with adipocyte dysfunction, inflammation, macrophage infiltration, and decreased fatty acid oxidation (FAO). Here, we report that the expression of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme in mitochondrial FAO, is higher in human adipose tissue macrophages than in adipocytes and that it is differentially expressed in visceral vs. subcutaneous adipose tissue in both an obese and a type 2 diabetes cohort. These observations led us to further investigate the potential role of CPT1A in adipocytes and macrophages. We expressed CPT1AM, a permanently active mutant form of CPT1A, in 3T3-L1 CARΔ1 adipocytes and RAW 264.7 macrophages through adenoviral infection. Enhanced FAO in palmitate-incubated adipocytes and macrophages reduced triglyceride content and inflammation, improved insulin sensitivity in adipocytes, and reduced endoplasmic reticulum stress and ROS damage in macrophages. We conclude that increasing FAO in adipocytes and macrophages improves palmitate-induced derangements. This indicates that enhancing FAO in metabolically relevant cells such as adipocytes and macrophages may be a promising strategy for the treatment of chronic inflammatory pathologies such as obesity and type 2 diabetes.

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L’OpenGL és un motor 3D que s’utilitza com a lligam entre el software i el hardware gràfic. Actualment és una de les tecnologies més utilitzades en el disseny d’aplicacions 3D. El treball està realitzat amb el programa Visual C++, que és el més recomanat per al desenvolupament d’aplicacions OpenGL. L’objectiu principal d’aquest treball és aprendre a programar amb aquest tipus de tecnologia que no hem estudiat durant el període de carrera. Un altre objectiu del treball era trobar una funció útil i pràctica per a l’aplicació i ens vam decantar per a realitzar un editor d’habitacions per un botiga o empresa de mobles. L’usuari pot de forma molt ràpida i senzilla dibuixar com és l’habitació que vol decorar de forma totalment personalitzada. El programa li generarà l’habitació en tres dimensions i amb els materials que s’han escollit (terra, parets, portes…). Després pot editar-hi mobles personalitzats o pertanyents a la llibreria del programa. El programa incorpora també una base de dades per a l’empresa que ens portarà la gestió de clients, habitacions, textures i mobles (permet ampliar la llibreria del programa). Un cop acabada l’habitació el programa ens hi permet fer una visita de forma interactiva i generar-ne la factura entre altres funcions. La conclusió principal després d’haver acabat aquest projecte, és que a part d’haver après OpenGL, hem aconseguit realitzar una aplicació molt pràctica de cares al disseny d’interiorisme.

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An evaluation of the performance of a continuous flow hydride generator-nebulizer for flame atomic absorption spectrometry was carried out. Optimization of nebulizer gas flow rate, sample acid concentration, sample and tetrahydroborate uptake rates and reductant concentration, on the As and Se absorbance signals was carried out. A hydrogen-argon flame was used. An improvement of the analytical sensitivity relative to the conventional bead nebulizer used in flame AA was obtained (2 (As) and 4.8 (Se) µg L-1). Detection limits (3σb) of 1 (As) and 1.3 (Se) µg L-1 were obtained. Accuracy of the method was checked by analyzing an oyster tissue reference material.

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To assess the psychological and family factors associated with suicidal ideation in preadolescent children, we studied a sample of 361 students, average age 9 years old. Twogroups were formed, on the basis of the presence (n = 34) or absence (n = 44) of suicidal ideation. Suicidal ideation was assessed with the Children’s Depression Inventory and the Children’s Depression Rating Scale-Revised. Depression, hopelessness, self-esteem, and perceived family environment were compared in both the suicidal ideation and the control groups. Students with suicidal ideation generally presented greater depressive symptoms and hopelessness, and lower self-esteem and family expressiveness, although there weredifferences both between sexes, and when the variable depression was controlled. Identifying these risk factors in pre-adolescents may have an impact on prevention of suicidal behavior at higher risk ages

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The characteristics of games make them excellent tools for multiple learning situations in the area of Physical Education, aswell as learning those necessary skills that allow students to handle social situations and especially conflicts. Understandingthat a conflict may be considered from a constructive perspective and that it may represent an excellent learningopportunity is a fundamental point. Games can help us in this task but it is important that the teacher knows theircharacteristics and which may be the most convenient in each educational moment

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Sport is a fundamental content in the teaching and learning of Physical Education independently of whether it is seen assuch by some authors. In whichever case according to the treatment that we give it, it will have sufficient educationalpotential without forgetting that it is the student who is the important figure in the process. To achieve the objectives wemust facilitate practices that are in agreement with the indispensable ethical principles to try to bring about a meaningfuland functional learning. The methodological criteria that we present in this article have this intention helped by examplesthat make it easier to understand the teaching learning process

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The physical education curriculum stresses the importance of improving students’ key motor skills. This idea agrees with the contributions of research into motor development concerning the important role these skills play in child development. In order to facilitate this improvement is essential to know the different basic aspects of how these key motor skills evolve as well as the essential factors related to the characteristics and conditions of educational practice