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Search Results: 1 - 10 of 256 matches for " Cerdá "
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Ciencias agrarias
Cerdá Cerdá, Antonio
Arbor : Ciencia, Pensamiento y Cultura , 2000,
Abstract: Not available La actividad investigadora en el área de Ciencias Agrarias compatibiliza y complementa la investigación básica con la aplicada en los aspectos relacionados con el suelo, el agua, la mejora vegetal y ganadera, los estreses bióticos y abióticos, los organismos fijadores de nitrógeno atmosférico, la fotosíntesis, etc. Los inicios de la actividad investigadora en este campo, la importancia en la actualidad, el potencial científico, el número y ubicación de los Institutos que la practican y las principales líneas de investigación del área se describen en esta publicación. Finalmente, se hace una reflexión acerca del papel de las Ciencias Agrarias en el futuro, basándose en que el sector primario tiene que seguir alimentando a la humanidad. La investigación agraria en el próximo milenio tendrá que desarrollar sistemas productivos que mejoren el manejo del suelo, agua y medio ambiente. Incidencia especial en todo lo referente a la transformación genética, a la protección vegetal, etc. En definitiva, desarrollar variedades de plantas que presente caracteres deseables en un concepto de agricultura sostenible.
Influencia de la litología en los procesos de erosión en badlands. Los casos de Anna (Valencia) y Petrer (Alicante)
Cerdà, A.
Pirineos : Revista de Ecología de Monta?a , 1997,
Abstract: By means of experiments with simulated rainfall the hydrological and erosional behaviour of degraded surfaces (badlands) developed on two different parent materials (marls and clays) is studied. On the Keuper clays, the ponding (4'07") and runoff (6' 36") initiation is delayed, the infiltration rates (38.63 mm h-1) are high, and the runoff coefficient (11.2 % after 30 minutes and 19.4 % after 60 minutes) and the erosion rates (13 g m2 h-1) are low. On the contrary, over Cretaceous marls, the ponding (1’ 37") and the surface runoff (2' 52") initiation is very rapid, the infiltration rates are low (11.2 mm h-1), and the runoff coefficient (64.7 % after 30 minutes and 72.2 % after 60 minutes) and the erosion rates (2,198 g m2 h-1) are very high. The activity of the surface runoff on the badlands over marls results in very low possibilities of soil and vegetation cover regeneration. [es] A partir de experimentos con lluvia simulada se estudia el comportamiento hidrológico y erosivo de superficies degradadas (badlands) desarrolladas sobre dos litologías distintas: margas y arcillas. En las arcillas del Keuper el encharcamiento (4' 07") y la escorrentía (6' 36") es retrasada, las tasas de infiltración son elevadas (38,63 mm h-1), y los coeficientes de escorrentía (11,2 % tras 30 minutos y 19,4 % tras 60 minutos) y las tasas de erosión (13 g m2 h-1) reducidas. En cambio, sobre margas Cretácicas, el encharcamiento (1' 37") y la escorrentía superficial (2' 52") se produce casi inmediatamente, las tasas de infiltración son muy bajas (11,2 mm h-1), y los coeficientes de escorrentía (64,7 % tras 30 minutos y 72,2 % tras 60 minutos) y las tasas de erosión son elevadísimas (2.198 g m2 h-1). La actividad de la arroyada superficial en los badlands sobre margas hace que las posibilidades de regeneración de los suelos y la cubierta vegetal sean reducidas. [fr] Sur la base de différentes experiments de pluie simulée l'auteur étudie le comportement hydrologique et érosif de deux badlands établis su deux types deroche-mère: mames et argile. Sur les argiles du Keuper l'accumulation d'eau (4' 05") et l'écoulement (6' 36") sont retardés, les taux d'infiltration son élevés (38,63 mmh-1) et les coefficients d'écoulement (11,2% après 30 minutes et 19,4% après 60 minutes) et les taux d'érosion sont réduits. Par contre, sur les marnes de Crétacé, l'accumulation d'eau (1' 37") et l'écoulement superficielle (2’ 52") ont lieu presque immédiatement, les taux d'infiltration restent très basse (11,2 mm h-1) et les coefficients d'écoulement (64,7% après 30 minutes et 72,2% après 60 minute
Preface
Cerdá Jaime
Brazilian Journal of Chemical Engineering , 2003,
Abstract:
Role of Aquaporins during Teleost Gametogenesis and Early Embryogenesis
Joan Cerdà
Frontiers in Physiology , 2011, DOI: 10.3389/fphys.2011.00066
Abstract: Aquaporins are believed to be involved in homeosmotic mechanisms of marine teleosts. Increasing data suggest that these molecular water channels play critical roles associated with the adaptation of gametes and early embryos to the external spawning environment. In this mini-review, we discuss recent studies suggesting the function of aquaporin-mediated fluid homeostasis during spermatozoa activation and egg formation in teleosts. In addition, we address the potential role of water channels in osmosensing and cell migration during early embryonic development.
A simple scheme to find the solutions to Brocard-Ramanujan Diophantine Equation n! + 1 = m^2
S. Cerdá
Mathematics , 2015,
Abstract: In this paper we present a method to find the solutions to the Brocard-Ramanujan's problem n! + 1 = m^2.
Analysis of the interaction between [Ru(phenanthroline)3]2+ and bovine serum albumin  [PDF]
Laura Luzuriaga, María Fernanda Cerdá
Advances in Biological Chemistry (ABC) , 2012, DOI: 10.4236/abc.2012.23033
Abstract: The interaction of compounds with potential use as pharmaceutical with a carrier protein as serum albumin is of great importance in their biodistribution. Albumin offers different sites for binding metallic compounds. Using a combination of spectropho-tometric and electrochemical techniques, the interaction between [Ru(phen)3]Cl2 (phen = phenantroline) and bovine serum albumin was evaluated. In particular, it was possible to calculate an apparent binding constant (Kb) of 4.4 × 103 (for concentrations expressed in M) for the main interaction site of the protein. A number of ca. 40 molecules of Ru-phen per molecule of BSA under saturation conditions, and a positive cooperative behavior towards association from the protein were found.
Mercado de trabajo y condiciones de vida en Mendoza a comienzos del siglo XX
Cerdá,Juan Manuel;
Mundo agrario , 2006,
Abstract: the aim of this work is to analyze the changes and continuities during the process of formation of the labor market in the province of mendoza in the early 1900s. wide sectors of the mendoza population saw their life conditions and social interactions change as a result of the absorption of a significant amount of immigrants by the end of 19 th century, together with a restructuring of production connected to the development of the wine industry. shortly after the turn of the century, wine had become the main productive activity of that province, which was the most important of the field in nation-wide terms. people involved in different stages of the wine production, from vine growers to industrialists, took part in a society increasingly heterogeneous and diverse. a society, product of the development of capitalism that went on in the province in the last third of 19 th century, that played a part in the process of inclusion of the argentinean economy in the world market. this period is of great significance because the productive system consolidated around wine production, thus shaping the regional labor market. in this context, the insertion of laborers was uneven in a productive process that requires highly seasonal and unspecialized labor.
An MILP framework for dynamic vehicle routing problems with time windows
Dondo,R.; Cerdá,J.;
Latin American applied research , 2006,
Abstract: a key issue in logistics is the efficient management of a vehicle fleet servicing a set of customers with known demands. every vehicle route must start and finish at the assigned depot, each customer is to be visited by a single vehicle and vehicle capacities must not be exceeded. these are the constraints for the capacitated vehicle routing problem (vrp) whose objective is usually the minimization of the travel distance. when every customer has an associated time window, we are dealing with the vehicle routing problem with time windows (vrptw), an np-hard problem extensively studied. in the static vprtw, all the problem data are given. a more challenging subject is the dynamic vrptw (drvptw) where routes must be periodically updated because of new service requests. in dvrptw, the information on the problem is time-dependent since the data are in part given a priori and in part dynamically updated. as a result, the best solution must be periodically revised. there are two classes of dvrptw solution methodologies: the immediate assignment that updates vehicle routes as soon as a new service request is received, and the deferred assignment retaining the new service calls for a certain time period before dispatching them all at once. the latter type has been adopted in this paper. at the time of revising their routes, the vehicles are already on duty and some nodes have already been visited. the remaining old customers that have designated vehicles are either being serviced or awaiting service. the customers to be considered in the dvrptw include not only old customers still to be serviced but also new visit requests. the dvrptw is tackled by solving a series of static vrptw problems, with each one being defined every time the input data is updated. the approach assumes that each vehicle will start its new route at the location where it is servicing or to which it is traveling.
Los Censos históricos como fuente para el estudio de la participación femenina en el mercado: El caso de la provincia de Mendoza a comienzos del siglo XX
Cerdá,Juan Manuel;
Mora (Buenos Aires) , 2009,
Abstract: the insertion of women in the labor market in the early 20th century is an issue scarcely explored by traditional historians and it deserves an individual analysis, not only from the point of view of the gender, but also as a social group that was affected by the capitalist development of the agro-exporting argentina. the purpose of this paper is to evaluate the potential and the limitations of the information provided by the national census of 1896, 1895, and 1914 in order to recreate the female contribution to the labor market. the forementioned process determined a change in the labor market as a whole that, according to some papers, brought along the reduction of the female share in the first decades of the 20th century. this paper aims to argue that point, based on the study of the province of mendoza. this province is significant given that, in the early 20th century, the production of wine became the main productive activity, thus transforming the labor market and having a distinctive impact on women.
An MILP framework for dynamic vehicle routing problems with time windows
R. Dondo,J. Cerdá
Latin American applied research , 2006,
Abstract: A key issue in logistics is the efficient management of a vehicle fleet servicing a set of customers with known demands. Every vehicle route must start and finish at the assigned depot, each customer is to be visited by a single vehicle and vehicle capacities must not be exceeded. These are the constraints for the capacitated vehicle routing problem (VRP) whose objective is usually the minimization of the travel distance. When every customer has an associated time window, we are dealing with the vehicle routing problem with time windows (VRPTW), an NP-hard problem extensively studied. In the static VPRTW, all the problem data are given. A more challenging subject is the dynamic VRPTW (DRVPTW) where routes must be periodically updated because of new service requests. In DVRPTW, the information on the problem is time-dependent since the data are in part given a priori and in part dynamically updated. As a result, the best solution must be periodically revised. There are two classes of DVRPTW solution methodologies: the immediate assignment that updates vehicle routes as soon as a new service request is received, and the deferred assignment retaining the new service calls for a certain time period before dispatching them all at once. The latter type has been adopted in this paper. At the time of revising their routes, the vehicles are already on duty and some nodes have already been visited. The remaining old customers that have designated vehicles are either being serviced or awaiting service. The customers to be considered in the DVRPTW include not only old customers still to be serviced but also new visit requests. The DVRPTW is tackled by solving a series of static VRPTW problems, with each one being defined every time the input data is updated. The approach assumes that each vehicle will start its new route at the location where it is servicing or to which it is traveling.
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