10,955 research outputs found
Trade and Labor Outcomes in Latin America's Rural Areas: A Cross-Household Surveys Approach
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
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 GPa. Near the ferromagnetic critical point
superconductivity is enhanced. Upper-critical field measurements under pressure
show attains remarkably large values, which provides solid evidence
for spin-triplet superconductivity over the whole pressure range. The obtained
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.
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
The performance of a large (3x3 ) 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
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
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
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
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 K. The precession frequency persists below the
bulk superconducting transition temperature K, where it measures
a local magnetic field T. The amplitude of the SR 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
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
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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