Computational analysis of the behavior of atmospheric pollution due to demographic, structural factors, vehicular flow and commerce activities

According to the latest assessments made by the world health organization (WHO2016), the atmospheric pollution (air), has become one of the main causes of morbidity and mortality in the world, with a steep growth of respiratory diseases, increase in lung cancer, ocular complications, and dermis diseases [1,2,3]. Currently, there are governments which still underestimate investments in environmental care, turning their countries into only consumers and predators of the ecosystem [1,2,3]. Worldwide, several cities have been implementing different regional strategies to decrease environmental pollution, however, these actions have not been effective enough and significant indices of contamination and emergency declarations persist [1,2,3]. Medellín is one of the cities most affected by polluting gases in Latin America due to the high growth of construction sector, high vehicular flow, increase in commerce, besides a little assertive planting trees system, among other reasons [1,2,3]. With the purpose of providing new researching elements which benefit the improvement of air quality in the cities of the world, it is pretended to mathematically model and computationally implement the behavior of the flow of air, e.g., in zones in the city of Medellín to determine the extent of pollution by tightness, impact of current architectural designs, vehicular transport, high commerce flow, and confinement in the public transport system. The simulations allowed to identify spotlights of particulate tightness caused by architectural designs of the city which do not benefit air flow. Also, recirculating gases were observed in different zones of the city. This research can offer greater knowledge around the incidence of pollution generated by structures and architecture. Likewise, these studies can contribute to a better urban, structural and ecological reordering in cities, the implementation of an assertive arborization system, and the possibility to orientate effective strategies over cleaning (purification) and contaminant extracting systems

Electrostatic internal energy using the method of images

For several configurations of charges in the presence of conductors, the method of images permits us to obtain some observables associated with such a configuration by replacing the conductors with some image charges. However, simple inspection shows that the potential energy associated with both systems does not coincide. Nevertheless, it can be shown that for a system of a grounded or neutral conductor and a distribution of charges outside, the external potential energy associated with the real charge distribution embedded in the field generated by the set of image charges is twice the value of the internal potential energy associated with the original system. This assertion is valid for any size and shape of the conductor, and regardless of the configuration of images required. In addition, even in the case in which the conductor is not grounded nor neutral, it is still possible to calculate the internal potential energy of the original configuration through the method of images. These results show that the method of images could also be useful for calculations of the internal potential energy of the original system.Comment: 5 pages, 3 figures. New discussions added. Minor change

Quantum point contact conductance in NINS junctions

The effect of an insulating barrier located at a distance $a$ from a NS quantum point contact is analyzed in this work. The Bogoliubov de Gennes equations are solved for NINS junctions (S: anysotropic superconductor, I: insulator and N: normal metal), where the NIN region is a quantum wire. For $a\neq0$, bound states and resonances in the differential conductance are predicted. These resonances depend on the symmetry of the pair potential, the strength of the insulating barrier and $a$. Our results show that in a NINS quantum point contact the number of resonances vary with the symmetry of the order parameter. This is to be contrasted with the results for the NINS junction, in which only the position of the resonances changes with the symmetry.Comment: 5 pages, 5 Figures, RevTex

Desempeño de los sistemas de vigilancia de salud pública durante la pandemia de influenza A (H1N1) en las Américas: prueba de un nuevo método basado en la Ley de Benford

The A(H1N1) influenza pandemic has been a challenge for public health surveillance systems in all countries. An objective evaluation has not been conducted, as yet, of the performance of those systems during the pandemic. This paper presents an algorithm based on Benford’s Law and the mortality ratio in order to evaluate the quality of the data and the sensitivity of surveillance systems. It analyses records of confirmed cases reported to the Pan American Health Organization by its 35 member countries between epidemiological weeks 13 and 47 in 2009. Seventeen countries did not fulfil Benford’s Law, and mortality exceeded the regional average in 40% of the countries. The results suggest uneven performance by surveillance systems in the different countries, with the most frequent problem being low diagnostic coverage. Benford’s Law proved to be a useful tool for the evaluation of a public health surveillance system’s performance

Element specific characterization of heterogeneous magnetism in (Ga,Fe)N films

We employ x-ray spectroscopy to characterize the distribution and magnetism of particular alloy constituents in (Ga,Fe)N films grown by metal organic vapor phase epitaxy. Furthermore, photoelectron microscopy gives direct evidence for the aggregation of Fe ions, leading to the formation of Fe-rich nanoregions adjacent to the samples surface. A sizable x-ray magnetic circular dichroism (XMCD) signal at the Fe L-edges in remanence and at moderate magnetic fields at 300 K links the high temperature ferromagnetism with the Fe(3d) states. The XMCD response at the N K-edge highlights that the N(2p) states carry considerable spin polarization. We conclude that FeN{\delta} nanocrystals, with \delta > 0.25, stabilize the ferromagnetic response of the films.Comment: 4 pages, 3 figures, 1 tabl

Domain-wall depinning assisted by pure spin currents

We study the depinning of domain walls by pure diffusive spin currents in a nonlocal spin valve structure based on two ferromagnetic permalloy elements with copper as the nonmagnetic spin conduit. The injected spin current is absorbed by the second permalloy structure with a domain wall and from the dependence of the wall depinning field on the spin current density we find an efficiency of 6*10^{-14}T/(A/m^2), which is more than an order of magnitude larger than for conventional current induced domain wall motion. Theoretically we reproduce this high efficiency, which arises from the surface torques exerted by the absorbed spin current that lead to efficient depinning.Comment: 11 pages, 3 figures, accepted for publication in Phys. Rev. Let

Combination of DROOL rules and Protégé knowledge bases in the ONTO-H annotation tool

ONTO-H is a semi-automatic collaborative tool for the semantic annotation of documents, built as a Protégé 3.0 tab plug-in. Among its multiple functionalities aimed at easing the document annotation process, ONTO-H uses a rule-based system to create cascading annotations out from a single drag and drop operation from a part of a document into an already existing concept or instance of the domain ontology being used for annotation. It also gives support to the detection of name conflicts and instance duplications in the creation of the annotations. The rule system runs on top of the open source rule engine DROOLS and is connected to the domain ontology used for annotation by means of an ad-hoc programmed Java proxy

phase coexistence in two dimensional fe 0 70 ni 0 30 films on w 110

n/

Finite voltage shot noise in normal-metal - superconductor junctions

We express the low-frequency shot noise in a disordered normal-metal - superconductor (NS) junction at finite (subgap) voltage in terms of the normal scattering amplitudes and the Andreev reflection amplitude. In the multichannel limit, the conductance exhibits resonances which are accompanied by an enhancement of the (differential) shot noise. In the study of multichannel single and double barrier junctions we discuss the noise properties of coherent transport at low versus high voltage with respect to the Andreev level spacing.Comment: 6 pages, Latex, 2 eps-figures, to be published in PRB, Appendix on Bogoliubov equation