961 research outputs found

    Location of franchises and large retail chains following the Great Recession. The case of the city of Zaragoza (Spain)

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    The current retail activity model is rapidly evolving, in order to adapt to consumer changes. For a long time, shopping centres have stood out as the most attractive model. However, the implementation of franchises and large commercial chains in cities is transforming the uses of urban space and configuring new spatial relationships. The city of Saragossa serves as a case study

    Weak Hopf algebras with projection and weak smash bialgebra structures

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    AbstractIn this paper we study weak Hopf algebras with projection. If f:H→B, g:B→H are morphisms of weak Hopf algebras such that g∘f=idH, we prove that it is possible to find an object BH, in the new category of weak Yetter–Drinfeld modules, that verifies similar conditions to the ones include in the definition of weak Hopf algebra. Finally, we define weak smash bialgebra structures and prove that, under central and cocentral conditions, BH and H determine an example of them

    Characterization of the rat Na+/nucleoside cotransporter 2 and transport of nucleoside-derived drugs using electrophysiological methods.

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    The Na(+)-dependent nucleoside transporter 2 (CNT2) mediates active transport of purine nucleosides and uridine as well as therapeutic nucleoside analogs. We used the two-electrode voltage-clamp technique to investigate rat CNT2 (rCNT2) transport mechanism and study the interaction of nucleoside-derived drugs with the transporter expressed in Xenopus laevis oocytes. The kinetic parameters for sodium, natural nucleosides, and nucleoside derivatives were obtained as a function of membrane potential. For natural substrates, apparent affinity (K(0.5)) was in the low micromolar range (12-34) and was voltage independent for hyperpolarizing membrane potentials, whereas maximal current (I(max)) was voltage dependent. Uridine and 2'-deoxyuridine analogs modified at the 5-position were substrates of rCNT2. Lack of the 2'-hydroxyl group decreased affinity but increased I(max). Increase in the size and decrease in the electronegativity of the residue at the 5-position affected the interaction with the transporter by decreasing both affinity and I(max). Fludarabine and formycin B were also transported with higher I(max) than uridine and moderate affinity (102 +/- 10 and 66 +/- 6 microM, respectively). Analysis of the pre-steady-state currents revealed a half-maximal activation voltage of about -39 mV and a valence of about -0.8. K(0.5) for Na(+) was 2.3 mM at -50 mV and decreased at hyperpolarizing membrane potentials. The Hill coefficient was 1 at all voltages. Direct measurements of radiolabeled nucleoside fluxes with the charge associated showed a ratio of two positive inward charges per nucleoside, suggesting a stoichiometry of two Na(+) per nucleoside. This discrepancy in the number of Na(+) molecules that bind rCNT2 may indicate a low degree of cooperativity between the Na(+) binding sites

    Particulate air pollution and health effects for cardiovascular and respiratory causes over an industrial neighborhood; Linking epidemiological time series studies and the power of a health perception survey

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    Talcahuano and Hualpén counties are one of the most highly industrial-polluted coastal zones in Chile, overhanging the iron foundry industry, coal burning power plants, chemical industry, and petroleum refinery, etc. The relationship between air pollution from PM2.5 measured at the Libertad monitoring station and health effects as the daily number of deaths and hospital admissions, for specific cardiovascular and respiratory diseases were studied. The results were compared with a health perception survey applied to the local population during spring 2008. Significant statistical associations were found between daily mortality and morbidity in Talcahuano-Hualpén area for cardiovascular and respiratory diseases and daily PM2.5 concentration, coinciding with the health perception of the inhabitants from these counties. The results suggest that point sources may be responsible for increased mortality in that industrial area. This has an important implication in relation with the size and chemical composition of the particles, but also for monitoring and control strategies. This is an abstract of a paper presented at the 103rd AWMA Annual Conference and Exhibition (Alberta, Canada 6/22-25/2010)

    Ubicación de franquicias y grandes cadenas comerciales después de la gran recesión. El caso de la ciudad de Zaragoza

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    El modelo comercial actual evoluciona de manera acelerada, adaptĂĄndose a los cambios del consumidor. Si hasta hace bien poco las grandes superficies comerciales eran las locomotoras de esta actividad, la implantaciĂłn de franquicias y grandes cadenas comerciales en las ciudades estĂĄ transformando los usos del espacio urbano y configurando nuevas relaciones espaciales. Como ejemplo se ha seleccionado la ciudad de Zaragoza

    Health Assessment and Seroepidemiologic Survey of Potential Pathogens in Wild Antillean Manatees (Trichechus manatus manatus)

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    The Antillean manatee (Trichechus manatus manatus), a subspecies of the West Indian manatee, inhabits fresh, brackish, and warm coastal waters distributed along the eastern border of Central America, the northern coast of South America, and throughout the Wider Caribbean Region. Threatened primarily by human encroachment, poaching, and habitat degradation, Antillean manatees are listed as endangered by the International Union for the Conservation of Nature. The impact of disease on population viability remains unknown in spite of concerns surrounding the species' ability to rebound from a population crash should an epizootic occur. To gain insight on the baseline health of this subspecies, a total of 191 blood samples were collected opportunistically from wild Antillean manatees in Belize between 1997 and 2009. Hematologic and biochemical reference intervals were established, and antibody prevalence to eight pathogens with zoonotic potential was determined. Age was found to be a significant factor of variation in mean blood values, whereas sex, capture site, and season contributed less to overall differences in parameter values. Negative antibody titers were reported for all pathogens surveyed except for Leptospira bratislava, L. canicola, and L. icterohemorrhagiae, Toxoplasma gondii, and morbillivirus. As part of comprehensive health assessment in manatees from Belize, this study will serve as a benchmark aiding in early disease detection and in the discernment of important epidemiologic patterns in the manatees of this region. Additionally, it will provide some of the initial tools to explore the broader application of manatees as sentinel species of nearshore ecosystem health

    Proton Conductors based on Metal Phosphonate Hybrid Materials for PEM Fuel Cells

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    The necessity of energy and power generation is constantly growing. Fossils fuels are quickly becoming unsatisfactory substrates due to both their emission of pollutants and their finite expectancy. Fuel cells are one of the best alternatives as they are clean, durable, and highly efficient 1. MOFs will be attractive candidates for this application because of their tuneable pore size functionality as well as their chemical and thermal stability and presence of acidic protons within their structure2. In the present work, we report the syntheses, crystal structural and proton conductivities of various metal phosphonate derivatives, using both rigid (5-(dihydroxyphosphoryl)isophthalic acid, PiPhtA and 2-hydroxyphosphonoacetic acid, HPAA) and flexible (hexa- or octamethylenediamine-N,N,Nâ€Č,Nâ€Č-tetrakis-(methylenephosphonic acid, H8HDTMP or H8ODTMP) multifunctional ligands. These materials show 3D open-frameworks containing 1D channels decorated with phosphonic and carboxylic acid groups and filled with hydrogen bonded water molecules what make them good candidates as proton conductors. For instance, Ca-PiPhtA, containing a rigid ligand, exhibits a proton conductivity of 5.7‱10-4 S/cm which increases to 6.6‱10-3 S/cm when the sample is exposed to ammonia vapors3. Other magnesium or lanthanides metal phosphonates, built with flexible ligands, show conductivities values range between 1.6 10-3 S/cm (for MgODTMP4) and 8.6 10-3 S/cm (for LaHDTMP5) at T=292K at ~100% relative humidity, and activation energies values typically attributed to a Grotthuss mechanism.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech

    Particulate air pollution and health effects for cardiovascular and respiratory causes in Temuco, Chile: A wood-smoke-polluted urban area

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    Temuco is one of the most highly wood-smoke-polluted cities in the world. Its population in 2004 was 340,000 inhabitants with 1587 annual deaths, of which 24% were due to cardiovascular and 11% to respiratory causes. For hospital admissions, cardiovascular diseases represented 6% and respiratory diseases 13%. Emergency room visits for acute respiratory infections represented 28%. The objective of the study presented here was to determine the relationship between air pollution from particulate matter less than or equal to 10 ÎŒm in aerodynamic diameter (PM10; mostly PM2.5, or particulate matter <2.5 ÎŒm in aerodynamic diameter) and health effects measured as the daily number of deaths, hospital admissions, and emergency room visits for cardiovascular, respiratory, and acute respiratory infection (ARI) diseases. The Air Pollution Health Effects European Approach (APHEA2) protocol was followed, and a multivariate Poisson regression model was fitted, controlling for trend, seasonality, and confounders for Temuco during 1998-2006. The results show that PM10 had a significant association with daily mortality and morbidity, with the elderly (population >65 yr of age) being the group that presented the greatest risk. The relative risk for respiratory causes, with an increase of 100 ÎŒg/m3 of PM10, was 1.163 with a 95% confidence interval (CI) of 1.057-1.279 for mortality, 1.137 (CI 1.096-1.178) for hospital admissions, and 1.162 for ARI (CI 1.144-1.181). There is evidence in Temuco of positive relationships between ambient particulate levels and mortality, hospital admissions, and ARI for cardiovascular and respiratory diseases. These results are consistent with those of comparable studies in other similar cities where wood smoke is the most important air pollution problem. Copyright 2009 Air & Waste Management Association

    Nonlinear Structural Analysis of the Elliptical Dome of the Church in the Universidad Laboral, Gijon, Spain

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    The Church of the Laboral University of GijĂłn has the world's largest elliptical masonry roof with 40.8 meters of mayor axis. This big structure is vertically supported with no columns using twenty pairs of masonry ribs crossing each other, and horizontally supported by means of two elliptical ring beams located at the top of the Church. In order to study this historical building, this paper presents the overall three-dimensional structural numerical analysis of the Church, taking into account different material nonlinearities - including masonry and reinforced concrete - as well as geometrical nonlinearities, such as contact effects among the different structural components of the building. Furthermore, a coupled thermal-structural analysis was carried out considering the summer temperature distribution and the Spanish standard rule dead and live loads. The most relevant results, in terms of maximum displacement, stress and, cracking and crushing phenomena are presented. Finally, valuable information from the interaction among the structural elements of the Church are discussed and the most critical points of the building are located, giving place to the most important conclusions of the nonlinear numerical analysis of this interesting structure
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