5,935 research outputs found

    A Study on the Impact of Climate Variability/Change on Water Resources in the Philippines

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    This paper presents an effort toward a better understanding of the potential impact of climate variability and change on the hydrology and water resources in the Philippines. Impacts of extreme events such as droughts are discussed. A preliminary study on the variability of inflow in relation to rainfall at the major dams in Luzon and the natural water reservoir of Lake Lanao is presented. Areas for future study are also mentioned.watershed

    A Study on the Impact of Climate Variability/Change on Water Resources in the Philippines

    Get PDF
    This paper presents an effort toward a better understanding of the potential impact of climate variability and change on the hydrology and water resources in the Philippines. Impacts of extreme events such as droughts are discussed. A preliminary study on the variability of inflow in relation to rainfall at the major dams in Luzon and the natural water reservoir of Lake Lanao is presented. Areas for future study are also mentioned.watershed

    Spontaneous chirality via long-range electrostatic forces

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    We consider a model for periodic patterns of charges constrained over a cylindrical surface. In particular we focus on patterns of chiral helices, achiral rings or vertical lamellae, with the constraint of global electroneutrality. We study the dependence of the patterns' size and pitch angle on the radius of the cylinder and salt concentration. We obtain a phase diagram by using numerical and analytic techniques. For pure Coulomb interactions, we find a ring phase for small radii and a chiral helical phase for large radii. At a critical salt concentration, the characteristic domain size diverges, resulting in macroscopic phase segregation of the components and restoring chiral symmetry. We discuss possible consequences and generalizations of our model.Comment: Revtex, 4 pages, 4 figure

    Charged Particles on Surfaces: Coexistence of Dilute Phases and Periodic Structures on Membranes

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    We consider a mixture of one neutral and two oppositely charged types of molecules confined to a surface. Using analytical techniques and molecular dynamics simulations, we construct the phase diagram of the system and exhibit the coexistence between a patterned solid phase and a charge-dilute phase. The patterns in the solid phase arise from competition between short-range immiscibility and long-range electrostatic attractions between the charged species. The coexistence between phases leads to observations of stable patterned domains immersed in a neutral matrix background.Comment: 5 pages, 3 figure

    La Garza Real en España. I. Población reproductora (1950-2000)

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    En este trabajo se analiza la evolución de la población reproductora de Garza Real, Ardea cinerea, en España durante el período 1950-2000. El territorio español se ha dividido en siete grandes zonas: Norte, Levante, y las cuencas de los cinco grandes ríos (Guadalquivir, Guadiana, Tajo, Duero y Ebro). Los datos sobre colonias y número de parejas nidificantes fueron obtenidos a partir de prospecciones de los autores, de citas bibliográficas y de comunicaciones de organismos y personas conocedoras de las colonias. Es probable que ya antes de 1950 hubiera colonias ocupadas, pero se carece de datos publicados sobre ellas. En 1950 pudo haber 168 parejas reproductoras en 4 colonias, mientras que en 2000 hubo 4790 parejas en 75 colonias. Las subpoblaciones de garza real asentadas de las cuencas del Duero y Tajo parecen estar próximas al equilibrio numérico, mientras que las del Ebro, Guadalquivir y Levante han aumentado notablemente su tamaño en la década 1990-2000. La cuenca del Guadiana contenía relativamente pocas parejas en el período de estudio y en el Norte de España la población reproductora de la garza real es aún poco significativa

    Monosized dripping mode of axisymmetric flow focusing

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    We identify and analyze the perfectly regular dripping mode of flow focusing. This mode occurs within narrow intervals of injected flow rates and applied pressure drops and leads to homogeneous-size droplets with diameters similar to or smaller than that of the discharge orifice. The balance between the local acceleration of the fluid particle and the applied pressure drop yields the scaling law for the droplet diameter. This scaling law is validated experimentally with excellent accord.Ministerio de Economía, Industria y Competitividad DPI2013-46485Gobierno de Extremadura GR1004

    An Optimisation Algorithm to Establish the Location of Stations of a Mixed Fleet Biking System: An Application to the City of Lisbon

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    AbstractThis paper presents the design and deployment of a bike-sharing system developed for Lisbon. The design of this new service is performed through an heuristic, encompassing a Mixed Integer Linear Program (MILP), that simultaneously optimise the location of shared biking stations, the fleet dimension and measuring the bicycle relocation activities required in a regular operation day. The results obtained for the several tested scenarios provided better insights into knowing how to improve the design and operation of these systems

    A Proposal for a Modified Moller-Plesset Perturbation Theory

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    A modified version of the Moller-Plesset approach for obtaining the correlation energy associated to a Hartree-Fock ground state is proposed. The method is tested in a model of interacting fermions that allows for an exact solution. Using up to third order terms improved results are obtained, even more accurate in the limit of loosely bound particles. This result suggests the possible convenience of the scheme for the study of chemical bound problems.Comment: 10 pages, 1 figur
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