10,669 research outputs found

    Trade and Labor Outcomes in Latin America's Rural Areas: A Cross-Household Surveys Approach

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    This paper explores the potential link between trade and labor outcomes in rural areas in Latin America by estimating cross household-survey regression models with microdata from 60 Latin American household surveys and country aggregate data. We find a significant positive association between labor outcomes in rural areas and some measures of international trade, in particular exports, trade as a share of GDP, and the price of exports. International trade has been associated with higher wages and labor income in rural areas, in particular for those workers located in the bottom quantiles of the conditional wage distribution. Instead, our results suggest that all individuals in rural areas benefit about the same due to higher export prices. Results for urban areas are rarely statistically significant.trade, wages, labor, rural, Latin America

    Enhancement of superconductivity near the ferromagnetic quantum critical point in UCoGe

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    We report a high-pressure single crystal study of the superconducting ferromagnet UCoGe. Ac-susceptibility and resistivity measurements under pressures up to 2.2 GPa show ferromagnetism is smoothly depressed and vanishes at a critical pressure pc=1.4p_c = 1.4 GPa. Near the ferromagnetic critical point superconductivity is enhanced. Upper-critical field measurements under pressure show Bc2(0)B_{c2}(0) attains remarkably large values, which provides solid evidence for spin-triplet superconductivity over the whole pressure range. The obtained pTp-T phase diagram reveals superconductivity is closely connected to a ferromagnetic quantum critical point hidden under the superconducting `dome'.Comment: 4 pages, 3 figures; accepted for publication in PR

    The contribution of targeted therapy to the neoadjuvant chemoradiation of rectal cancer.

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    Neoadjuvant chemoradiation therapy is a commonly used option aimed to make less aggressive surgery approaches and to improve quality of life allowing a high proportion of patients operated with sphincter-sparing surgical techniques in locally advanced rectal cancer (LARC). During the last 5 years a number of studies have tested the efficacy of more intensive chemotherapeutic approaches by combining irinotecan or oxaliplatin with fluoropyrimidines and standard radiation treatments as well as testing combined treatments with targeted agents directed against epidermal growth factor receptor (EGFR) or angiogenesis. Herein, we review the results and critiques of the published studies based on the introduction of novel targeted agents in neoadjuvant therapy of LARC

    Performance of a large limited streamer tube cell in drift mode

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    The performance of a large (3x3 cm2cm^2) streamer tube cell in drift mode is shown. The detector space resolution has been studied using cosmic muons crossing an high precision silicon telescope. The experimental results are compared with a GARFIELD simulation.Comment: 18 pages, 7 figures. Accepted by Nucl. Instr. and Methods

    Inferior alveolar nerve impairment after mandibular sagittal split osteotomy: an analysis of spontaneous recovery pattern observed in 60 patients

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    Sensory impairment after bilateral sagittal split osteotomy (BSSO) due to inferior alveolar nerve (IAN) lesions may be either temporary or permanent and either complete or partial. The aim of this prospective study is to evaluate, by means of objective sensory testing, IAN sensory disturbances development in patients who underwent BSSO.IAN sensory disturbances development at the first week, fourth week, sixth month, and twelfth month of follow-up review in a group of 60 patients who underwent BSSO from January 1, 1998, to July 31, 1999, at the Maxillofacial Surgery Department of the "La Sapienza" University of Rome. The 60 patients were examined in the presurgical period; the IAN functionality regarding thermal sensibility, nociception, and two-point discrimination, was assessed at follow-up in 120 sides. In our study the highest rate of spontaneous recovery of the entire IAN functionality was observed at the sixth month. This finding witnesses how neuropraxia and axonotmesis give a spontaneous recovery that most frequently occurs within 6 months from surgery, independently from age and sex of the patient. The persistence of anesthesia over 12 months could be a sign of neurotmesis

    Exact and Asymptotic Inference in Clinical Trials with Small Event Rates under Inverse Sampling

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    In this paper we discuss statistical inference for a two-by-two table under inverse sampling, where the total number of cases is fixed by design. We demonstrate that the exact unconditional distributions of some relevant statistics differ from the distributions under conventional sampling, where the sample size is fixed by design. This permits us to define a simple unconditional alternative to Fisher’s exact test. We provide an asymptotic argument including simulations to demonstrate that there is little power-loss associated with the alternative test when the expected response rates are rare. We then apply the method to design a clinical trial in cataract surgery, where a rare side effect occurs in one in one-thousand patients. Objective of the trial is to demonstrate that adjuvant treatment with an antibiotic will reduce this risk to one in two-thousand. We use an inverse sampling design and demonstrate how to set this up in a sequential manner. Particularly simple stopping rules can be defined when using the unconditional alternative to Fisher’s exact test

    Electronic contribution to the oscillations of a gravitational antenna

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    We carefully analyse the contribution to the oscillations of a metallic gravitational antenna due to the interaction between the electrons of the bar and the incoming gravitational wave. To this end, we first derive the total microscopic Hamiltonian of the wave-antenna system and then compute the contribution to the attenuation factor due to the electron-graviton interaction. As compared to the ordinary damping factor, which is due to the electron viscosity, this term turns out to be totally negligible. This result confirms that the only relevant mechanism for the interaction of a gravitational wave with a metallic antenna is its direct coupling with the bar normal modes.Comment: 25 pages, no figure

    Muon spin rotation and relaxation in the superconducting ferromagnet UCoGe

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    We report zero-field muon spin rotation and relaxation measurements on the superconducting ferromagnet UCoGe. Weak itinerant ferromagnetic order is detected by a spontaneous muon spin precession frequency below the Curie temperature TC=3T_C = 3 K. The μ+\mu^+ precession frequency persists below the bulk superconducting transition temperature Tsc=0.5T_{sc} = 0.5 K, where it measures a local magnetic field Bloc=0.015B_{loc} = 0.015 T. The amplitude of the μ\muSR signal provides unambiguous proof for ferromagnetism present in the whole sample volume. We conclude ferromagnetism coexists with superconductivity on the microscopic scale.Comment: 4 pages, 3 figures, accepted for publication in PR

    Plasma Membranes in Psoriatic Cells. A Freeze-fracture Study

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    A freeze-fracture study of affected and unaffected psoriatic skin has demonstrated the presence of marked modification of the plasma membrane in the psoriatic lesion. In the lower layers of the epidermis, an increase of membrane associated particles was observed in many keratinocytes, possibly representing the morphological intramembranous equivalent of changes in the outer cell membrane demonstrated with cytochemical techniques. Furthermore, in the malphighian layer, numerous gap junctions have been found, which may be interpreted as a phenomenon compensating the uncontrolled proliferation, and may represent a point of differentiation between cell proliferation in psoriasis and neoplasia. This technique confirmed the poor tendency to adhesion of keratinocytes in extrajunctional areas, which had already been shown by other morphological techniques

    Mechanical Systems: Symmetry and Reduction

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    Reduction theory is concerned with mechanical systems with symmetries. It constructs a lower dimensional reduced space in which associated conservation laws are taken out and symmetries are \factored out" and studies the relation between the dynamics of the given system with the dynamics on the reduced space. This subject is important in many areas, such as stability of relative equilibria, geometric phases and integrable systems
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