273 research outputs found

    Child health in rural Colombia: determinants and policy interventions

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    In this paper we study the determinants of child anthropometrics on a sample of poor Colombian children living in small municipalities. We focus on the influence of household consumption, and public infrastructure. We take into account the endogeneity of household consumption using two different sets of instruments: household assets and municipality average wage. We find that household consumption is an important determinant of child health. The importance of the effect is confirmed by the two different sets of instruments. We find that using ordinary least squares would lead to conclude that the importance of household consumption is much smaller than the instrumental variable estimates suggest. The presence of a public hospital in the municipality positively influences child health. The extent of the piped water network positively influences the health of children if their parents have at least some education. The number of hours of growth and development check-ups is also an important determinant of child health. We find that some of these results only show up once squared and interaction terms have been included in the regression. Overall, our estimates suggest that both public and private investments are important to improve child health in poor environments

    Total thyroidectomy versus hemithyroidectomy for patients with follicular neoplasm. A cost-utility analysis

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    AbstractIntroductionThyroid nodules are a common condition. Overall, 20% of the nodules assessed with FNAB correspond to the follicular pattern. A partial thyroidectomy is the minimal procedure that should be performed to determine the nature of these nodules. Some authors have suggested performing a total thyroidectomy based on the elimination of reoperation and ultrasound follow-up. The aim of this study was to evaluate the most cost-useful surgical strategy in a patient with an undetermined nodule, assessing complications, reoperation, recurrence and costs.Material and methodsA cost-utility study was designed to compare hemithyroidectomy and total thyroidectomy. The outcomes were complications (definitive RLN palsy, permanent hypoparathyroidism, reoperation for cancer, and recurrence of the disease), direct costs and utility. We used the payer perspective at 5 years. A deterministic and probabilistic sensitivity analysis was completed.ResultsIn a deterministic analysis, the cost, utility and cost-utility ratio was COP 12.981.801,44.5andCOP12.981.801, 44.5 and COP 291.310 for total thyroidectomy and COP 14.309.889,42.0and14.309.889, 42.0 and 340.044 for partial thyroidectomy, respectively. The incremental cost-utility ratio was −$535.302 favoring total thyroidectomy. Partial thyroidectomy was more cost-effective when the risks of RLN injury and definitive hypoparathyroidism were greater than 8% and 9% in total thyroidectomy, respectively. In total, 46.8% of the simulations for partial thyroidectomy were located in the quadrant of more costly and less effective.ConclusionUnder a common range of complications, and considering the patient's preference and costs, total thyroidectomy should be selected as the most cost-effective treatment for patients with thyroid nodules and follicular patterns

    Synthesis of quinoxaline 1,4-di-N-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

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    We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield

    Caustic Formation in Tachyon Effective Field Theories

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    Certain configurations of D-branes, for example wrong dimensional branes or the brane-antibrane system, are unstable to decay. This instability is described by the appearance of a tachyonic mode in the spectrum of open strings ending on the brane(s). The decay of these unstable systems is described by the rolling of the tachyon field from the unstable maximum to the minimum of its potential. We analytically study the dynamics of the inhomogeneous tachyon field as it rolls towards the true vacuum of the theory in the context of several different tachyon effective actions. We find that the vacuum dynamics of these theories is remarkably similar and in particular we show that in all cases the tachyon field forms caustics where second and higher derivatives of the field blow up. The formation of caustics signals a pathology in the evolution since each of the effective actions considered is not reliable in the vicinity of a caustic. We speculate that the formation of caustics is an artifact of truncating the tachyon action, which should contain all orders of derivatives acting on the field, to a finite number of derivatives. Finally, we consider inhomogeneous solutions in p-adic string theory, a toy model of the bosonic tachyon which contains derivatives of all orders acting on the field. For a large class of initial conditions we conclusively show that the evolution is well behaved in this case. It is unclear if these caustics are a genuine prediction of string theory or not.Comment: 23 pages, 5 figures; accepted for publication in JHEP. Revised derivation of eikonal equation for the DBI action. Added comments concerning the relationship between p-adic string theory and tachyon matter. Added second example of inhomogeneous evolution in p-adic string theory. Misleading statements concerning caustic-free evolution removed, references adde

    “Desenvolver virtualmente”: Estudio de los fardos funerarios de PachacĂĄmac a travĂ©s de la tomografĂ­a computarizada y los rayos X.

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    El proyecto colaborativo "Las momias como microcosmos“ tiene como objetivo evaluar el impacto del Imperio Inca en la costa central. En el 2019 se iniciaron las investigaciones sobre una colecciĂłn de fardos funerarios del Intermedio TardĂ­o recuperados en el marco del proyecto de rescate arqueolĂłgico para la construcciĂłn del Museo Nacional de ArqueologĂ­a (MUNA) y que hoy forman parte de la colecciĂłn del Museo Pachacamac; con la finalidad de reconstruir la osteobiografĂ­a de los individuos, para conocer sus condiciones de salud, enfermedades y sus ritos funerarios mediante el anĂĄlisis paleoradiolĂłgico no destructivo a travĂ©s de CT-Scan y rayos-X

    Improved imputation quality of low-frequency and rare variants in European samples using the 'Genome of the Netherlands'

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    Although genome-wide association studies (GWAS) have identified many common variants associated with complex traits, low-frequency and rare variants have not been interrogated in a comprehensive manner. Imputation from dense reference panels, such as the 1000 Genomes Project (1000G), enables testing of ungenotyped variants for association. Here we present the results of imputation using a large, new population-specific panel: the Genome of The Netherlands (GoNL). We benchmarked the performance of the 1000G and GoNL reference sets by comparing imputation genotypes with 'true' genotypes typed on ImmunoChip in three European populations (Dutch, British, and Italian). GoNL showed significant improvement in the imputation quality for rare variants (MAF 0.05-0.5%) compared with 1000G. In Dutch samples, the mean observed Pearson correlation, r 2, increased from 0.61 to 0.71. W

    Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

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    We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e,eâ€Čp)Îł(e,e'p)\gamma exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the WW-dependence at fixed Q2=1Q^2=1 GeV2^2, and for the Q2Q^2-dependence at fixed WW near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q2Q^2-dependence is smooth. The measured ratio of H(e,eâ€Čp)Îł(e,e'p)\gamma to H(e,eâ€Čp)π0(e,e'p)\pi^0 cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest WW (1.8-1.9 GeV) show a striking Q2Q^2- independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.Comment: 20 pages, 8 figures. To appear in Phys.Rev.

    Photoproduction of mesons off nuclei

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    Recent results for the photoproduction of mesons off nuclei are reviewed. These experiments have been performed for two major lines of research related to the properties of the strong interaction. The investigation of nucleon resonances requires light nuclei as targets for the extraction of the isospin composition of the electromagnetic excitations. This is done with quasi-free meson photoproduction off the bound neutron and supplemented with the measurement of coherent photoproduction reactions, serving as spin and/or isospin filters. Furthermore, photoproduction from light and heavy nuclei is a very efficient tool for the study of the interactions of mesons with nuclear matter and the in-medium properties of hadrons. Experiments are currently rapidly developing due to the combination of high quality tagged (and polarized) photon beams with state-of-the-art 4pi detectors and polarized targets