1,116 research outputs found

    CURRENCY HEDGING AND INTERNATIONAL PORTFOLIO INVESTMENTS: A LOCAL PERSPECTIVE

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    Should we use currency hedging? Naturally the answer depends on who asks the question and the effects of hedging on risk and expected returns. This paper considers the perspective of an international investor based in Chile, but also explores whether similar conclusions can be obtained from the perspective of a global investor that invests in Chile. It also analyzes whether the exchange rate regime affects the answers to this question. This question is relevant since foreign portfolio investments by locals has increased significantly in recent years and a large fraction of it is hedged, partly as a response to current pension fund regulations. The paper proposes methodologies and provides evidence which should allow local investors to find optimal hedging policies.

    The Structure of Real Interest Rates in Chile.

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    This paper describes the structure of real interest rates (the real yield curve) in Chile and shows its evolution through time. It provides a practical tool for the systematic study of the determinants of Chilean yield curves. Empirical estimations are based on transaction and auction data for Central Bank bonds and pension recognition bonds issued by the government, applying the Nelson and Siegel method. Estimation results are used to measure the liquidity premium in the market maker’s bond yield, simulate the evolution of the very short and long-term rates, and analyze issues of Central Bank zero-coupon bonds and the response of domestic interest rates to local and international economic events.

    Coulomb blockade conductance peak fluctuations in quantum dots and the independent particle model

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    We study the combined effect of finite temperature, underlying classical dynamics, and deformations on the statistical properties of Coulomb blockade conductance peaks in quantum dots. These effects are considered in the context of the single-particle plus constant-interaction theory of the Coulomb blockade. We present numerical studies of two chaotic models, representative of different mean-field potentials: a parametric random Hamiltonian and the smooth stadium. In addition, we study conductance fluctuations for different integrable confining potentials. For temperatures smaller than the mean level spacing, our results indicate that the peak height distribution is nearly always in good agreement with the available experimental data, irrespective of the confining potential (integrable or chaotic). We find that the peak bunching effect seen in the experiments is reproduced in the theoretical models under certain special conditions. Although the independent particle model fails, in general, to explain quantitatively the short-range part of the peak height correlations observed experimentally, we argue that it allows for an understanding of the long-range part.Comment: RevTex 3.1, 34 pages (including 13 EPS and PS figures), submitted to Phys. Rev.

    Semliki Forest virus induced, immune mediated demyelination: the effect of irradiation

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    International audienceThe Dark Energy Camera has captured a large set of images as part of Science Verification (SV) for the Dark Energy Survey (DES). The SV footprint covers a large portion of the outer Large Magellanic Cloud (LMC), providing photometry 1.5 mag fainter than the main sequence turn-off of the oldest LMC stellar population. We derive geometrical and structural parameters for various stellar populations in the LMC disc. For the distribution of all LMC stars, we find an inclination of i = -38.14° ± 0.08° (near side in the north) and a position angle for the line of nodes of θ0 = 129.51° ± 0.17°. We find that stars younger than ∼4 Gyr are more centrally concentrated than older stars. Fitting a projected exponential disc shows that the scale radius of the old populations is R>4 Gyr = 1.41 ± 0.01 kpc, while the younger population has R = 0.72 ± 0.01 kpc. However, the spatial distribution of the younger population deviates significantly from the projected exponential disc model. The distribution of old stars suggests a large truncation radius of Rt = 13.5 ± 0.8 kpc. If this truncation is dominated by the tidal field of the Galaxy, we find that the LMC is {∼eq } 24^{+9}_{-6} times less massive than the encircled Galactic mass. By measuring the Red Clump peak magnitude and comparing with the best-fitting LMC disc model, we find that the LMC disc is warped and thicker in the outer regions north of the LMC centre. Our findings may either be interpreted as a warped and flared disc in the LMC outskirts, or as evidence of a spheroidal halo component

    Chemokine (C-C Motif) Receptor 2 Mediates Dendritic Cell Recruitment to the Human Colon but Is Not Responsible for Differences Observed in Dendritic Cell Subsets, Phenotype, and Function Between the Proximal and Distal Colon.

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    BACKGROUND & AIMS: Most knowledge about gastrointestinal (GI)-tract dendritic cells (DC) relies on murine studies where CD103+ DC specialize in generating immune tolerance with the functionality of CD11b+/- subsets being unclear. Information about human GI-DC is scarce, especially regarding regional specifications. Here, we characterized human DC properties throughout the human colon. METHODS: Paired proximal (right/ascending) and distal (left/descending) human colonic biopsies from 95 healthy subjects were taken; DC were assessed by flow cytometry and microbiota composition assessed by 16S rRNA gene sequencing. RESULTS: Colonic DC identified were myeloid (mDC, CD11c+CD123-) and further divided based on CD103 and SIRPα (human analog of murine CD11b) expression. CD103-SIRPα+ DC were the major population and with CD103+SIRPα+ DC were CD1c+ILT3+CCR2+ (although CCR2 was not expressed on all CD103+SIRPα+ DC). CD103+SIRPα- DC constituted a minor subset that were CD141+ILT3-CCR2-. Proximal colon samples had higher total DC counts and fewer CD103+SIRPα+ cells. Proximal colon DC were more mature than distal DC with higher stimulatory capacity for CD4+CD45RA+ T-cells. However, DC and DC-invoked T-cell expression of mucosal homing markers (β7, CCR9) was lower for proximal DC. CCR2 was expressed on circulating CD1c+, but not CD141+ mDC, and mediated DC recruitment by colonic culture supernatants in transwell assays. Proximal colon DC produced higher levels of cytokines. Mucosal microbiota profiling showed a lower microbiota load in the proximal colon, but with no differences in microbiota composition between compartments. CONCLUSIONS: Proximal colonic DC subsets differ from those in distal colon and are more mature. Targeted immunotherapy using DC in T-cell mediated GI tract inflammation may therefore need to reflect this immune compartmentalization

    The caribbean coastal marine productivity program (CARICOMP)

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    CARICOMP is a regional scientific program to study land-sea interaction processes in the Caribbean coastal zone. It has been collecting data since 1992, when a Data Management Centre was established at the University of the West Indies in Jamaica. Initially it focuses on documenting the structure and productivity of major coastal communities (mangrove forests, seagrass meadows and coral reefs) at relatively undisturbed sites in diverse physical settings. Second, by regular recording of physical and biological parameters, it monitors for change, seeking to distinguish natural from anthropogenic disturbance. Third, it constitutes a regional network of observers, able to collaborate on studies of region-wide events. Examples are presented of the diverse data sets collected by the Program.Fil: Alcolado, Pedro M.. Instituto de Oceanología; CubaFil: Alleng, Gerard. No especifíca;Fil: Bonair, Kurt. No especifíca;Fil: Bone, David. Universidad Simón Bolívar; VenezuelaFil: Buchan, Kenneth. No especifíca;Fil: Bush, Phillippe G.. Protection and Conservation Unit; Islas CaimánFil: De Meyer, Kalli. No especifíca;Fil: Garcia, Jorge R.. Universidad de Puerto Rico; Puerto RicoFil: Garzón Ferreira, Jaime. Instituto de Investigaciones Marinas y Costeras; ColombiaFil: Gayle, Peter M. H.. Discovery Bay Marine Laboratory; JamaicaFil: Gerace, Donald T.. Bahamian Field Station; BahamasFil: Geraldes, Francisco X.. Universidad Autonoma de Santo Domingo.; República DominicanaFil: Dahlgren, Eric Jordán. Universidad Nacional Autónoma de México; MéxicoFil: Kjferve, Björn. University of South Carolina; Estados UnidosFil: Klein, Eduardo. Universidad Simón Bolívar; VenezuelaFil: Koltes, Karen. Smithsonian Institution; Estados UnidosFil: Laydoo, Richard S.. No especifíca;Fil: Linton, Dulcie M.. University of the West Indies ; JamaicaFil: Ogden, John C.. Florida Institute of Oceanography; Estados UnidosFil: Oxenford, Hazel A.. McGill University; BarbadosFil: Parker, Christoph. McGill University; BarbadosFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Pors, Leon P. P. J.. Universidad Simón Bolívar; VenezuelaFil: Ramírez Ramírez, Javier. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Física; MéxicoFil: Ruiz Rentería, Francisco. Universidad Nacional Autónoma de México; MéxicoFil: Ryan, Joseph D.. Centro de Investigación y Documentación de la Costa Atlántica; NicaraguaFil: Smith, Struan R.. Bermuda Biological Station for Research; BermudasFil: Tschirky, John. Latin American and Caribbean Division; Estados UnidosFil: Varela, Ramon. Estación de Investigaciones Marinas de Margarita; VenezuelaFil: Walker, Susan. No especifíca;Fil: Weil, Ernesto. Universidad de Puerto Rico; Puerto RicoFil: Wiebe, William J.. University of Georgia; Estados UnidosFil: Woodley, Jeremy D.. University of the West Indies; JamaicaFil: Zieman, Joseph C.. University of Virginia; Estados Unido

    Impact of multi-metals (Cd, Pb and Zn) exposure on the physiology of the yeast Pichia kudriavzevii

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    Metal contamination of the environment is frequently associated to the presence of two or more metals. This work aimed to study the impact of a mixture of metals (Cd, Pb and Zn) on the physiology of the non-conventional yeast Pichia kudriavzevii. The incubation of yeast cells with 5 mg/l Cd, 10 mg/l Pb and 5 mg/l Zn, for 6 h, induced a loss of metabolic activity (assessed by FUN-1 staining) and proliferation capacity (evaluated by a clonogenic assay), with a small loss of membrane integrity (measured by trypan blue exclusion assay). The staining of yeast cells with calcofluor white revealed that no modification of chitin deposition pattern occurred during the exposure to metal mixture. Extending for 24 h, the exposure of yeast cells to metal mixture provoked a loss of membrane integrity, which was accompanied by the leakage of intracellular components. A marked loss of the metabolic activity and the loss of proliferation capacity were also observed. The analysis of the impact of a single metal has shown that, under the conditions studied, Pb was the metal responsible for the toxic effect observed in the metal mixture. Intracellular accumulation of Pb seems to be correlated with the metals toxic effects observed.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project "BioInd-Biotechnology and Bioengineering for improved Industrial and Agro-Food processes" (NORTE-07-0124-FEDER-000028), Co-funded by the Programa Operacional Regional do Norte (ON.2-O Novo Norte), QREN, FEDER. Manuela D. Machado gratefully acknowledges the post-doctoral grant from FCT (SFRH/BPD/72816/2010). Vanessa A. Mesquita gratefully acknowledges the grant from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES). The authors also thank to Doctor Rosane Freitas Schwan to offer the yeast strain and to Doctor Helena M.V.M. Soares, from the Faculty of Engineering of Porto University, for the use of analytical facilities (AAS with flame atomization and AAS with electrothermal atomization)

    Singing the same tune? International continuities and discontinuities in how police talk about using force

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    This article focuses on a research project conducted in six jurisdictions: England, The Netherlands, Germany, Australia, Venezuela, and Brazil. These societies are very different ethnically, socially, politically, economically, historically and have wildly different levels of crime. Their policing arrangements also differ significantly: how they are organised; how their officers are equipped and trained; what routine operating procedures they employ; whether they are armed; and much else besides. Most relevant for this research, they represent policing systems with wildly different levels of police shootings, Police in the two Latin American countries represented here have a justified reputation for the frequency with which they shoot people, whereas at the other extreme the police in England do not routinely carry firearms and rarely shoot anyone. To probe whether these differences are reflected in the way that officers talk about the use of force, police officers in these different jurisdictions were invited to discuss in focus groups a scenario in which police are thwarted in their attempt to arrest two youths (one of whom is a known local criminal) by the youths driving off with the police in pursuit, and concludes with the youths crashing their car and escaping in apparent possession of a gun, It might be expected that focus groups would prove starkly different, and indeed they were, but not in the way that might be expected. There was little difference in affirmation of normative and legal standards regarding the use of force. It was in how officers in different jurisdictions envisaged the circumstances in which the scenario took place that led Latin American officers to anticipate that they would shoot the suspects, whereas officers in the other jurisdictions had little expectation that they would open fire in the conditions as they imagined them to be
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