306 research outputs found

    Threshold Effects in the Relationship Between Inflation and Growth

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    This paper re-examines the issue of the existence of threshold effects in the relationship between inflation and growth, using new econometric techniques that provide appropriate procedures for estimation and inference. The threshold level of inflation above which inflation significantly slows growth is estimated at 1-3 percent for industrial countries and 11-12 percent for developing countries. The negative and significant relationship between inflation and growth, for inflation rates above the threshold level, is quite robust with respect to the estimation method, perturbations in the location of the threshold level, the exclusion of high-inflation observations, data frequency, and alternative specifications. Copyright 2001, International Monetary Fund

    Time Series Analysis of Export Demand Equations: A Cross-Country Analysis

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    The paper estimates export demand elasticities for a large number of developing and industrial countries, using time-series techniques that account for the nonstationarity in the data. The average long-run price and income elasticities are found to be approximately -1 and 1.5, respectively. Thus, exports do react to both the trade partners' income and to relative prices. Africa faces the lowest income elasticities for its exports, while Asia has both the highest income and price elasticities. The price and income elasticity estimates have good statistical properties. Copyright 1999, International Monetary Fund

    Semiparametric Inference and Lower Bounds for Real Elliptically Symmetric Distributions

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    This paper has a twofold goal. The first aim is to provide a deeper understanding of the family of the Real Elliptically Symmetric (RES) distributions by investigating their intrinsic semiparametric nature. The second aim is to derive a semiparametric lower bound for the estimation of the parametric component of the model. The RES distributions represent a semiparametric model where the parametric part is given by the mean vector and by the scatter matrix while the non-parametric, infinite-dimensional, part is represented by the density generator. Since, in practical applications, we are often interested only in the estimation of the parametric component, the density generator can be considered as nuisance. The first part of the paper is dedicated to conveniently place the RES distributions in the framework of the semiparametric group models. The second part of the paper, building on the mathematical tools previously introduced, the Constrained Semiparametric Cram\'{e}r-Rao Bound (CSCRB) for the estimation of the mean vector and of the constrained scatter matrix of a RES distributed random vector is introduced. The CSCRB provides a lower bound on the Mean Squared Error (MSE) of any robust MM-estimator of mean vector and scatter matrix when no a-priori information on the density generator is available. A closed form expression for the CSCRB is derived. Finally, in simulations, we assess the statistical efficiency of the Tyler's and Huber's scatter matrix MM-estimators with respect to the CSCRB.Comment: This paper has been accepted for publication in IEEE Transactions on Signal Processin

    Mediterranean Founder Mutation Database (MFMD): Taking Advantage from Founder Mutations in Genetics Diagnosis, Genetic Diversity and Migration History of the Mediterranean Population

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    The Mediterranean basin has been the theater of migration crossroads followed by settlement of several societies and cultures in prehistoric and historical times, with important consequences on genetic and genomic determinisms. Here, we present the Mediterranean Founder Mutation Database (MFMD), established to offer web-based access to founder mutation information in the Mediterranean population. Mutation data were collected from the literature and other online resources and systematically reviewed and assembled into this database. The information provided for each founder mutation includes DNA change, amino-acid change, mutation type and mutation effect, as well as mutation frequency and coalescence time when available. Currently, the database contains 383 founder mutations found in 210 genes related to 219 diseases. We believe that MFMD will help scientists and physicians to design more rapid and less expensive genetic diagnostic tests. Moreover, the coalescence time of founder mutations gives an overview about the migration history of the Mediterranean population. MFMD can be publicly accessed from http://mfmd.pasteur.ma

    Iron for Africa-Report of an Expert Workshop.

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    Scientific experts from nine countries gathered to share their views and experience around iron interventions in Africa. Inappropriate eating habits, infections and parasitism are responsible for significant prevalence of iron deficiency, but reliable and country-comparable prevalence estimates are lacking: improvements in biomarkers and cut-offs values adapted to context of use are needed. Benefits of iron interventions on growth and development are indisputable and outweigh risks, which exist in populations with a high infectious burden. Indeed, pathogen growth may increase with enhanced available iron, calling for caution and preventive measures where malaria or other infections are prevalent. Most African countries programmatically fortify flour and supplement pregnant women, while iron deficiency in young children is rather addressed at individual level. Coverage and efficacy could improve through increased access for target populations, raised awareness and lower cost. More bioavailable iron forms, helping to decrease iron dose, or prebiotics, which both may lower risk of infections are attractive opportunities for Africa. Fortifying specific food products could be a relevant route, adapted to local context and needs of population groups while providing education and training. More globally, partnerships involving various stakeholders are encouraged, that could tackle all aspects of the issue

    Higgs Physics: Theory

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    I review the theoretical aspects of the physics of Higgs bosons, focusing on the elements that are relevant for the production and detection at present hadron colliders. After briefly summarizing the basics of electroweak symmetry breaking in the Standard Model, I discuss Higgs production at the LHC and at the Tevatron, with some focus on the main production mechanism, the gluon-gluon fusion process, and summarize the main Higgs decay modes and the experimental detection channels. I then briefly survey the case of the minimal supersymmetric extension of the Standard Model. In a last section, I review the prospects for determining the fundamental properties of the Higgs particles once they have been experimentally observed.Comment: 21 pages, 15 figures. Talk given at the XXV International Symposium on Lepton Photon Interactions at High Energies (Lepton Photon 11), 22-27 August 2011, Mumbai, Indi

    Direct detection of Higgs-portal dark matter at the LHC

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    We consider the process in which a Higgs particle is produced in association with jets and show that monojet searches at the LHC already provide interesting constraints on the invisible decays of a 125 GeV Higgs boson. Using the existing monojet searches performed by CMS and ATLAS, we show the 95% confidence level limit on the invisible Higgs decay rate is of the order of the total Higgs production rate in the Standard Model. This limit could be significantly improved when more data at higher center of mass energies are collected, provided systematic errors on the Standard Model contribution to the monojet background can be reduced. We also compare these direct constraints on the invisible rate with indirect ones based on measuring the Higgs rates in visible channels. In the context of Higgs portal models of dark matter, we then discuss how the LHC limits on the invisible Higgs branching fraction impose strong constraints on the dark matter scattering cross section on nucleons probed in direct detection experiments.Comment: 6 pages, 3 figures; v2: references added; v3: monojet and Higgs data updated, version published in EPJ

    Charged Higgs production from SUSY particle cascade decays at the LHC

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    We analyze the cascade decays of the scalar quarks and gluinos of the Minimal Supersymmetric extension of the Standard Model, which are abundantly produced at the Large Hadron Collider, into heavier charginos and neutralinos which then decay into the lighter ones and charged Higgs particles, and show that they can have substantial branching fractions. The production rates of these Higgs bosons can be much larger than those from the direct production mechanisms, in particular for intermediate values of the parameter tan⁥ÎČ\tan \beta, and could therefore allow for the detection of these particles. We also discuss charged Higgs boson production from direct two-body top and bottom squark decays as well as from two- and three-body gluino decays.Comment: 30 pages with 10 figures, latex. Uses axodraw.sty and epsfig.st

    Degradation of pollutants in water by Fenton-like oxidation over LaFe-catalysts: Optimization by experimental design

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    The effect of different parameters such as temperature, type of catalyst and hydrogen peroxide (H2O2) concentration on the degradation of pollutants in water by Fenton-like oxidation was studied by using the Box-Behnken design (BBD), an effective statistical model to design the experiments. Concerning the heterogeneous catalysts, three bimetallic catalysts with lanthanum (La) and iron (Fe) ion-exchanged into zeolites (NaY and ZSM5) and a natural clay from Morocco were prepared and used for Fenton-like oxidation of organic pollutants in water. Tartrazine (Tar, a food coloring compound known as E102) and caffeine (Caf, a stimulant drug present in popular beverages such as coffee and tea) were selected as pollutants due to their presence in several commercial products for daily consumption. The BBD model indicated that the optimum catalytic conditions for Fenton-like reaction with an initial pollutant concentration of 30ppm at pH 3.0 were T=40°C and 90mM of H2O2. The maximum conversion values achieved with the best catalyst, LaFeZSM5, were 96.6% for Tar after 180min and 51.0% for Caf after 300min of reaction. To increase the conversion of Caf, a modified zeolite electrode was used for electro Fenton-like oxidation without H2O2, at room temperature.O.A. thanks to ERASMUS + Program for the mobility Ph.D. grant and O.B. thanks to Fundação para CiĂȘncia e Tecnologia, Portugal (FCT) for his Ph.D. grant (SFRH/BD/140362/2018).This research work has been funded by national funds funded through FCT/MCTES (PIDDAC) over the projects: LA/P/0045/2020 (ALiCE), UIDB/50020/2020 and UIDP/50020/2020 (LSRE-LCM), UIDB/04469/2020 (CEB) and by LA/P/0029/2020 (LABBELS), Centre of Chemistry (UID/QUI/0686/2020) and project BioTecNorte (operation NORTE-01-0145-FEDER-000004), supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

    Remission of hypertension after treatment of giant simple renal cyst: a case report

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    Renal cysts are common in old patients, and usually remain untreated. Giant renal cysts measuring more than 15 cm in greatest diameter are uncommon and the association with hypertension is very rare. We present a case of a 25-year-old woman with a giant right renal cyst associated with hypertension that was treated by laparoscopic excision, followed by resolution hypertension
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