3,160 research outputs found

    Diseño de las obras de protección costera del malecon de la libertad, provincia del Guayas

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    PRESENTA ESTUDIOS DE INGENIERIA QUE PERMITIERON ESTABLECER LAS CONDICIONES GEOTECNICAS, OCEANOGRAFICAS Y AMBIENTALES NECESARIAS PARA EL DISEÑO. SE PLANTEARON TRES ALTERNATIVAS DE DISEÑO PARA LAS OBRAS COSTERAS, CON ALGUNAS VARIANTES EN LAS MISMAS, LAS CUALES FUERON EVALUADAS EN CUANTO A SUS CARACTERISTICAS TECNICAS Y SUS COSTOS. SE DETERMINO QUE LA MEJOR ALTERNATIVA PARA LA ESTABILIZACION DE LA COSTA, Y PARA LA PROTECCION DEL NUEVO MALECON CONTRA EL ATAQUE DEL OLEAJE, CONSISTIA EN LA CONSTRUCCION DE CINCO ESCOLLERAS COSTA-AFUERA, Y EL REVESTIMIENTO CON ENROCADO A LO LARGO DEL MALECON. SE DESCRIBE DISEÑOS ARQUITECTONICOS Y URBANISTICOS. DISEÑO DE OBRAS CIVILES PARA LA PROTECCION COSTERA

    Early Science with the Large Millimetre Telescope: Molecules in the Extreme Outflow of a proto-Planetary Nebula

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    Extremely high velocity emission likely related to jets is known to occur in some proto-Planetary Nebulae. However, the molecular complexity of this kinematic component is largely unknown. We observed the known extreme outflow from the proto-Planetary Nebula IRAS 16342-3814, a prototype water fountain, in the full frequency range from 73 to 111 GHz with the RSR receiver on the Large Millimetre Telescope. We detected the molecules SiO, HCN, SO, and 13^{13}CO. All molecular transitions, with the exception of the latter are detected for the first time in this source, and all present emission with velocities up to a few hundred km s−1^{-1}. IRAS 16342-3814 is therefore the only source of this kind presenting extreme outflow activity simultaneously in all these molecules, with SO and SiO emission showing the highest velocities found of these species in proto-Planetary Nebulae. To be confirmed is a tentative weak SO component with a FWHM ∼\sim 700 km s−1^{-1}. The extreme outflow gas consists of dense gas (nH2>_{\rm H_2} > 104.8^{4.8}--105.7^{5.7} cm−3^{-3}), with a mass larger than ∼\sim 0.02--0.15 M⊙_{\odot}. The relatively high abundances of SiO and SO may be an indication of an oxygen-rich extreme high velocity gas.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society Letter

    Thermal Diffusion and Specular Reflection, Monte Carlo-based Study on Human Skin via Pulsed Fiber Laser Energy

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    The aim of traditional Chinese medicine (TCM) in acupuncture is sometimes to restore and regulate energy balance by stimulating specific points along the specific meridians traced on the human body via different techniques such as mechanical pressure, moxibustion and others. Hence, physicians have struggled to improve treatment for common diseases such as migraine and headaches. Heat stimulation and some pharmacological effects from moxa have been attributed to the therapeutic efficacy of such techniques. As heat can diffuse through the tissue, skins temperature will rise in the surrounding tissue. In this work, heat diffusion on a simple, 5-layer model of human skin is presented. Based on this, and by using Monte Carlo techniques, a photon or a photon package is launched into the tissue for mimicking the propagation of such photons at two different wavelengths through the tissue. The method generally describes the scholastic nature of radiation interactions. Most of the laser energy is deposited within a volume which cross-sectional area is the size of the beam itself. As could be seen, in the epidermis layer of the model, the heat does not go deep and nearly all the heat diffusion occurs on the edges of the beam, causing losses. Heat dissipation occurs faster and goes down to 2°C in the adipose tissue since there is low water content in this region. On the contrary, there is a fast heat increase in the muscle layer, up to 6°C at the most superficial layer. Since melanin is the most important epidermal chromophore, it can be noted that light shows strong absorption via melanin, at 690nm laser wavelength. In the papillary dermis the heat decreases and spreads out to the surrounding tissue. Once it reaches the adipose tissue, the heat is not absorbed enough; therefore, it is transmitted into the muscle, where the temperature rise is higher and reaches nearly 40 °C. Finally, photodynamics in a simple 5-layer skin model were explored at two laser wavelengths: 690nm and 1069nm, where no thermal damage would be expected, given the energy level of the employed pulses. Such pulsed laser energy levels remain to be tested in living tissue

    Lindane and Endosulfan Sulfate Isomers in Crassostrea virginica (Gmelin, 1791) Oyster Populations in Lagoon Systems from Central Gulf of Mexico

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    The aim of this study was to determine Lindane and Endosulfan Sulfate isomers in Crassostrea virginica oyster populations (Gmelin, 1791) in the Mandinga and Alvarado lagoon systems located in the central Gulf of Mexico. Samples were taken from the main oyster banks of each lagoon system, during the three representative seasons of the region, wet, dry and north winds. By means of free diving, 30 commercial size oysters (7 ± 3 cm) were collected in four oyster banks or stations of the Mandinga lagoon system, totaling 360 organisms, while in the Alvarado lagoon system there were a total of 90 oysters during the annual cycle. Concentration of lindane and endosulfan sulfate isotopes in C. virginica was performed with a gas chromatograph (Thermo Electron Model Trace GC Ultra 115V, Thermo Fisher Scientific Inc©, Monterrey, Nuevo León, México) with an Electron capture detector. Results showed that in the Alvarado Lagoon system mean concentrations of C. virginica oysters for lindane pesticide were 4.11 ± 3.83 ng⋅g-1, whereas for the Mandinga lagoon system, were 8.69 ± 5.15 ng⋅g-1. Endosulfan sulfate showed the highest average concentration in the Mandinga lagoon system with 24.68 ± 1.20 ng ⋅g-1. In addition, the endosulfan sulfate presents differences in its spatial distribution; high concentration levels in the Mandinga lagoon system whereas the lindane heterogeneity at all sampling points in both lagoons. Values of concentrations and relationships between compounds suggest recent contributions that could correspond to the excessive fluctuations of water discharged into the lagoon caused by the atypical rains of the year of sampling. It was concluded that endosulfan sulfate and lindane show concentration in all the points of sampling in both lagoons

    Properties of iron-modified-by-silver supported on mordenite as catalysts for nox reduction

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    A series of mono and bimetallic catalysts based on a Fe-Ag mixture deposited on mordenite was prepared by ion-exchange and evaluated in the catalytic activity test of the de-NOx reaction in the presence of CO/C3H6. The activity results showed that the most active samples were the Fe-containing ones, and at high temperatures, a co-promoter effect of Ag on the activity of Fe catalysts was also observed. The influence of the order of cation deposition on catalysts formation and their physicochemical properties was studied by FTIR (Fourier Transform Infrared Spectroscopy) of adsorbed NO, XANES (X-ray Absorption Near-Edge Structure), and EXAFS (Extended X-ray Absorption Fine Structure) and discussed in terms of the state of iron. Results of Fe K-edge XANES oscillations showed that, in FeMOR catalysts, iron was present in a disordered state as Fe3+ and Fe2+. In FeAgMOR, the prevailing species was Fe3+, while in the AgFeMOR catalyst, the state of iron was intermediate or mixed between FeMOR and FeAgMOR. The Fe K-edge EXAFS results were characteristic of a disordered phase, the first coordination sphere being asymmetric with two different Fe-O distances. In FeAgMOR and AgFeMOR, coordination of Fe-O was similar to Fe2O3 with a few amount of Fe2+ species. We may conclude that, in the bimetallic FeAgMOR and AgFeMOR samples, a certain amount of tetrahedral Al3+ ions in the mordenite framework is replaced by Fe3+ ions, confirming the previous reports that these species are active sites for the de-NOx reaction. Based on the thermodynamic analysis and experimental data, also, it was confirmed that the order of deposition of the components influenced the mechanism of active sites’ formation during the two steps ion-exchange synthesis

    Seasonal and Spatial Patterns in Salinity, Nutrients, and Chlorophyll α in the Alvarado Lagoonal System, Veracruz, Mexico

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    Ten monthly collections, distributed among three seasons, were taken from July 2000 to June 2001 in the Alvarado lagoonal system, Veracruz, Mexico. Variables measured in situ included dissolved oxygen, salinity, and water temperature. Water samples were collected to determine concentrations of ammonium, nitrates, nitrites, orthophosphates, total phosphorus and chlorophyll α. Collections representing the rainy season were taken in September and October, those for the nortes season were taken in November, December, and January, and dry season collections were taken during February, March, May June, and July. There was seasonal and spatial variation in nutrient concentrations, and they were related to the discharge of the rivers; concentrations increased during the rainy and nortes seasons. Other factors affecting water quality included the constant discharge of organic materials into the system, resuspension of sediments during the nortes season and the biological activity within the system that assimilated the nutrients in the water. The Alvarado lagoonal system has three separate zones based on physicochemical characteristics; Camaronera Lagoon, Buen Pais Lagoon and the urban zone of Alvarado Lagoon, and the river zone in Alvarado Lagoon

    Drosophila Insulin Pathway Mutants Affect Visual Physiology and Brain Function Besides Growth, Lipid, and Carbohydrate Metabolism

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    OBJECTIVE—Type 2 diabetes is the most common form of diabetes worldwide. Some of its complications, such as retinop-athy and neuropathy, are long-term and protracted, with an un-clear etiology. Given this problem, genetic model systems, such as in flies where type 2 diabetes can be modeled and studied, offer distinct advantages. RESEARCH DESIGN AND METHODS—We used individual flies, control, and mutant individuals with partial loss-of-function insulin pathway genes. We measured wing size and tested body weight for growth phenotypes, the latter by means of a microbal-ance. We studied total lipid and carbohydrate content, lipids by a reaction in single fly homogenates with vanillin-phosphoric acid, and carbohydrates with an anthrone-sulfuric acid reaction. Cholinesterase activity was measured using the Ellman method in head homogenates from pooled fly heads, and electroretinogram

    A Strategy to Measure the Dark Energy Equation of State using the HII galaxy Hubble Relation & X-ray AGN Clustering: Preliminary Results

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    We explore the possibility of setting stringent constraints to the Dark Energy equation of state using alternative cosmic tracers like: (a) the Hubble relation using HII galaxies, which can be observed at much higher redshifts (z~3.5) than those currently traced by SNIa samples, and (b) the large-scale structure using the clustering of X-ray selected AGN,which have a redshift distribution peaking at z~1. We use extensive Monte-Carlo simulations to define the optimal strategy for the recovery of the dark-energy equation of state using the high redshift (z~2) Hubble relation, but accounting also for the effects of gravitational lensing, which for such high redshifts can significantly affect the derived cosmological constraints. Based on a "Figure of Merit" analysis, we provide estimates for the number of 2<z<3.5 tracers needed to reduce the cosmological solution space, presently provided by the Constitution SNIa set, by a desired factor. We find that it is much more efficient to increase the number of tracers than to reduce their individual uncertainties. Finally, we propose a framework to put constraints on the dark energy equation of state by using the joint likelihood of the X-ray AGN clustering and of the Hubble relation cosmological analyses. A preliminary joint analysis using the X-ray AGN clustering of the 2XMM survey and the Hubble relation of the Constitution SNIa set provide: Omega_m= 0.31+-0.01 and w=-1.06+-0.05. We also find that the joint SNIa-2XMM analysis provides significantly more stringent cosmological constraints, increasing the Figure of Merit by a factor ~2, with respect to that of the joint SNIa-BAO analysis.Comment: MNRAS in press, 12 colour figure
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