bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluación costo efectividad del tratamiento en un solo tiempo de colelitiasis con coledocolitiasis mediante el uso de laparoscopia y su asociación con el abordaje laparo-endoscópico
Authors: Mendoza Orquera Alicia Guadalupe , Vélez Páez Jorge Luis 
Published: February 2018

El tratamiento de colelitiasis con coledocolitiasis (CBD) en tiempo único es efectivo, más la relación costo efectividad del acceso exclusivo por laparoscopia es aún motivo de investigación siendo este nuestro objetivo. Métodos: análisis retrospectivo, transversal de pacientes operados laparoscópicamente por colelitiasis y coledocolitiasis en servicios públicos de salud, distribuidos en dos grupos: Grupo L (exploración laparoscópica de la vía biliar, Hospital Pablo Arturo Suárez - Quito (H.PAS). Grupo LE (exploración laparo endoscópica, Hospital de Clínicas de la Facultad de Medicina de Ribeirão Preto - Universidad de Sao Paulo (USP HCFMRP) período de junio 2016- junio 2017. Resultados: Los grupos fueron homogéneos para la mayoría de las variables epidemiológicas y clínicas antes de los procedimientos quirúrgicos, la efectividad del tratamiento quirúrgico valorado como aclaramiento del colédoco fue 100% , la tasa de complicaciones precoces fueron equivalentes en los dos grupos (16,6 %); el tiempo quirúrgico en el G L fue 168,36 minutos (58,36 minutos DP), y en el G LE de 117,06 minutos (29,43 DP), p= 0,001; el período de internación fue 2,2 días (1,83 DP) en el Grupo I-L y para el Grupo LE 1. 1 días (1,83 DP) p= 0,01. La selección de casos en el GLE benefició a 14 pacientes tratados ambulatoriamente, con una efectividad de 100% y un costo medio de atención hospitalaria de $1179,81 (DP $200,60), en comparación con los pacientes que requirieron hospitalización $ 1509,19 (DP $ 426,04) generando una diferencia de costos estadística significativa p=0,039. Concluimos que el tratamiento quirúrgico laparoendoscópico es costo efectivo.
Los estilos de aprendizajes y el rendimiento académico
Authors: Alcivar Vaca Paola Rosalin 
Published: February 2018

En el siglo XXI las teorías del aprendizaje son de mayor interés en los investigadores, naciendo nuevas incógnitas como por ejemplo el ¿Cómo aprendemos? Que detonan estudios importantes sobre el individuo como ente aprendiz dejando de lado aspectos como estrategias, técnicas, tipo, niveles. En el proceso educativo muy pocas veces se ha hablado de los estilos de aprendizaje, es decir su manera de apropiarse del conocimiento, ya que todos reciben el mismo contenido pero no todos se lo adjudican. Uno de los problemas que principales que existen en la educación es que conductismo del aprendizaje, dejando a un lado los aspectos metodológicos como son las estrategias didácticas de acuerdo a cada estilo de aprender de los educandos. En el desarrollo de esta investigación se planteó como objetivo general analizar de qué manera incidencia de los estilos de aprendizaje en el rendimiento académico de los estudiantes de la carrera de educación parvularia de la Universidad Laica Eloy Alfaro de Manabí, así como conocer las estrategias y el nivel de capacitación que poseen los docentes sobre los estilos de aprendizajes. El estudio se realizó con la población total de estudiantes legalmente matriculados, docentes y autoridad de la Carrera de Educación parvularia; las técnicas que se utilizaron para la recolección de datos fueron la entrevista, la encuesta y el Test de CHOEA. Se consideró importante realizar este estudio para conocer cómo la relación de las dos variables permitiendo conocer como el estudiante aprende, concluyendo que el docente utiliza estrategias didácticas tradicionalistas.
A New Mathematical Model of Heat Equations And its Application on the Agriculture Soil
Authors: Allahem Ali , Boulaaras Salah , Zennir Khaled , Haiour Mohamed 
Published: February 2018

The goal of this paper is to provide a mathematical model which based on numerical simulation applied to heat equationsÂ and comparing the obtained results with virtualÂ temperatures results for different depths of the homogeneous agricultural soil. TheÂ model was treated through this research that enable to know the degree of soil temperature homogeneous without recourse to tools ofÂ measuring physical expensive. The importance of this lies in the agricultural seed germination at temperatures suitable.
Volumetric analysis of magnetic resonance–guided focused ultrasound thalamotomy lesions
Authors: Harary Maya , Essayed Walid I. , Valdes Pablo A. , McDannold Nathan , Cosgrove G. Rees 
Published: February 2018

OBJECTIVEMagnetic resonance–guided focused ultrasound (MRgFUS) thalamotomy was recently approved for use in the treatment of medication-refractory essential tremor (ET). Previous work has described lesion appearance and volume on MRI up to 6 months after treatment. Here, the authors report on the volumetric segmentation of the thalamotomy lesion and associated edema in the immediate postoperative period and 1 year following treatment, and relate these radiographic characteristics with clinical outcome.METHODSSeven patients with medication-refractory ET underwent MRgFUS thalamotomy at Brigham and Women’s Hospital and were monitored clinically for 1 year posttreatment. Treatment effect was measured using the Clinical Rating Scale for Tremor (CRST). MRI was performed immediately postoperatively, 24 hours posttreatment, and at 1 year. Lesion location and the volumes of the necrotic core (zone I) and surrounding edema (cytotoxic, zone II; vasogenic, zone III) were measured on thin-slice T2-weighted images using Slicer 3D software.RESULTSPatients had significant improvement in overall CRST scores (baseline 51.4 ± 10.8 to 24.9 ± 11.0 at 1 year, p = 0.001). The most common adverse events (AEs) in the 1-month posttreatment period were transient gait disturbance (6 patients) and paresthesia (3 patients). The center of zone I immediately posttreatment was 5.61 ± 0.9 mm anterior to the posterior commissure, 14.6 ± 0.8 mm lateral to midline, and 11.0 ± 0.5 mm lateral to the border of the third ventricle on the anterior commissure–posterior commissure plane. Zone I, II, and III volumes immediately posttreatment were 0.01 ± 0.01, 0.05 ± 0.02, and 0.33 ± 0.21 cm3, respectively. These volumes increased significantly over the first 24 hours following surgery. The edema did not spread evenly, with more notable expansion in the superoinferior and lateral directions. The spread of edema inferiorly was associated with the incidence of gait disturbance. At 1 year, the remaining lesion location and size were comparable to those of zone I immediately posttreatment. Zone volumes were not associated with clinical efficacy in a statistically significant way.CONCLUSIONSMRgFUS thalamotomy demonstrates sustained clinical efficacy at 1 year for the treatment of medication-refractory ET. This technology can create accurate, predictable, and small-volume lesions that are stable over time. Instances of AEs are transient and are associated with the pattern of perilesional edema expansion. Additional analysis of a larger MRgFUS thalamotomy cohort could provide more information to maximize clinical effect and reduce the rate of long-lasting AEs.
Predicting lesion size during focused ultrasound thalamotomy: a review of 63 lesions over 3 clinical trials
Authors: Bond Aaron E. , Elias W. Jeffrey 
Published: February 2018

OBJECTIVEThe goal of this study was to improve the predictability of lesion size during focused ultrasound (FUS) thalamotomy procedures.METHODSTreatment profiles and T2-weighted MRI (T2 MRI) studies obtained in 63 patients who participated in 3 clinical trials of FUS thalamotomy from February 2011 to March 2015 were reviewed retrospectively. Four damage estimate models were compared with lesion sizes measured on postprocedural T2 MRI. Models were based on 54°C × 3 seconds, 240 cumulative equivalent minutes at 43°C, and simple thermal threshold analysis, which recorded the maximum diameter that reached a temperature of at least 51°C and 54°C. Energy requirements per °C thermal rise above 37°C were also recorded.RESULTSLesion diameters from T2 MRI correlated poorly from the day of the procedure to day 1 postprocedure (mean increase 78% [SD 79%]). There was more predictability of lesion size from day 1 to day 30, with a mean reduction in lesion diameter of 11% (SD 24%). Of the 4 models tested, the most correlative model to day 1 findings on T2 MRI was a 51°C threshold. The authors observed an increase in the energy requirement for each subsequent treatment sonication, with the largest percentage increase from treatment sonication 1 to treatment sonication 2 (mean increase 20% in energy required per °C increase in temperature above 37°C).CONCLUSIONSAt the margins, 51°C temperature threshold diameters correlated best to lesion diameters measured at day 1 with T2 MRI. The lesion size from T2 MRI decreases from day 1 to day 30 in a predictable manner, much more so than from the day of the procedure to day 1 postprocedure. Energy requirements per °C rise above 37°C continuously increase with each successive sonication.
Effects on cognition and quality of life with unilateral magnetic resonance–guided focused ultrasound thalamotomy for essential tremor
Authors: Jung Na Young , Park Chang Kyu , Chang Won Seok , Jung Hyun Ho , Chang Jin Woo 
Published: February 2018

OBJECTIVEAlthough neurosurgical procedures are effective treatments for controlling involuntary tremor in patients with essential tremor (ET), they can cause cognitive decline, which can affect quality of life (QOL). The purpose of this study is to assess the changes in the neuropsychological profile and QOL of patients following MR-guided focused ultrasound (MRgFUS) thalamotomy for ET.METHODSThe authors prospectively analyzed 20 patients with ET who underwent unilateral MRgFUS thalamotomy at their institute in the period from March 2012 to September 2014. Patients were regularly evaluated with the Clinical Rating Scale for Tremor (CRST), neuroimaging, and cognition and QOL measures. The Seoul Neuropsychological Screening Battery was used to assess cognitive function, and the Quality of Life in Essential Tremor Questionnaire (QUEST) was used to evaluate the postoperative change in QOL.RESULTSThe total CRST score improved by 67.3% (from 44.75 ± 9.57 to 14.65 ± 9.19, p < 0.001) at 1 year following MRgFUS thalamotomy. Mean tremor scores improved by 68% in the hand contralateral to the thalamotomy, but there was no significant improvement in the ipsilateral hand. Although minimal cognitive decline was observed without statistical significance, memory function was much improved (p = 0.031). The total QUEST score also showed the same trend of improving (64.16 ± 17.75 vs 27.38 ± 13.96, p < 0.001).CONCLUSIONSThe authors report that MRgFUS thalamotomy had beneficial effects in terms of not only tremor control but also safety for cognitive function and QOL. Acceptable postoperative changes in cognition and much-improved QOL positively support the clinical significance of MRgFUS thalamotomy as a new, favorable surgical treatment in patients with ET.
Development of the wave spectrum of the northern region of the Bay of Bengal based on Indian National Centre for Ocean Information Services (INCOIS) moored buoy data
Authors: Mansur M. , Enam F B , Baree M S 
Published: February 2018

The wave spectrum of the northern region of the Bay of Bengal is developed and analyzed. A meticulous analysis shows variations of the wave spectrum of this region in the four meteorological seasons namely spring (March, April, May), summer (June, July, August), autumn (September, October, November) and winter (December, January, February). Real time wave data have been collected from a moored buoy of Indian National Centre for Ocean Information Service (INCOIS) located at 89.675° E longitude and 18.191° N latitude. Varyingtwo-parameter (mean wave period and significant wave height) wave spectra for the four seasons are obtained and formulae for all the four spectra are derived. The adequacy of the different spectra is indicated by comparing with different wave spectra of known formulations.
APPLICATION OF PATTERN RECOGNITION TECHNIQUES FOR FAULT DETECTION OF CLUTCH RETAINER OF TRACTOR
Authors: Bahrami Mostafa , Javadikia Hossein , Ebrahimi Ebrahim 
Published: February 2018

This study develops a technique based on pattern recognition for fault diagnosis of clutch retainer mechanism of MF285 tractor using the neural network. In this technique, time features and frequency domain features consist of Fast Fourier Transform (FFT) phase angle and Power Spectral Density (PSD) proposes to improve diagnosis ability. Three different cases, such as: normal condition, bearing wears and shaft wears were applied for signal processing. The data divides in two parts; in part one 70% data are dataset1 and in part two 30% for dataset2.At first, the artificial neural networks (ANN) are trained by 60% dataset1 and validated by 20% dataset1 and tested by 20% dataset1. Then, to more test of the proposed model, the network using the datasets2 are simulated. The results indicate effective ability in accurate diagnosis of various clutch retainer mechanism of MF285 tractor faults using pattern recognition networks.
Tensile Studies on Random Oriented Human Hair Fiber Reinforced Polyester Composites
Authors: Rao P. Divakara , Kiran C. Udaya , Prasad K. Eshwara 
Published: February 2018

Composite specimens are prepared by impregnating human hair in polyester resin. Randomlyoriented chopped Human hair with varied weight ratios and Fiber lengths are used for the present experimental study. The composites are compression moulded using hand layup technique. An attempt is made to find out the influence of fiber weight ratio and length on the Tensile strength and tensile modulus. Optimum Fiber weight ratio and Fiber length are identified for maximizing the tensile strength and tensile modulus of the Human hair polyester composites. Experiments are carried out as per the standards and results are discussed.Further, Tensile stress and Tensile Modulus of the composite at optimum fiber length are estimated using different theoretical models and are compared with the experimental results.
In the Crosshair: Astrometric Exoplanet Detection with WFIRST's Diffraction Spikes
Authors: Melchior Peter , Spergel David , Lanz Arianna 
Published: February 2018

Abstract

WFIRST will conduct a coronagraphic program that characterizes the atmospheres of planets around bright nearby stars. When observed with the WFIRST Wide Field Camera, these stars will saturate the detector and produce very strong diffraction spikes. In this paper, we forecast the astrometric precision that WFIRST can achieve by centering on the diffraction spikes of highly saturated stars. This measurement principle is strongly facilitated by the WFIRST H4RG detectors, which confine excess charges within the potential well of saturated pixels. By adopting a simplified analytical model of the diffraction spike caused by a single support strut obscuring the telescope aperture, integrated over the WFIRST pixel size, we predict the performance of this approach with the Fisher-matrix formalism. We discuss the validity of the model and find that

astrometric precision is achievable with a single 100 s exposure of an

or a

star. We discuss observational limitations from the optical distortion correction and pixel-level artifacts, which need to be calibrated at the level of

so as to not dominate the error budget. To suppress those systematics, we suggest a series of short exposures, dithered by at least several hundred pixels, to reach an effective per-visit astrometric precision better than

. If this can be achieved, a dedicated WFIRST GO program will be able to detect Earth-mass exoplanets with orbital periods of

around stars within a few pc as well as Neptune-like planets with shorter periods or around more massive or distant stars. Such a program will also enable mass measurements of many anticipated direct-imaging exoplanet targets of the WFIRST coronagraph and a “starshade” occulter.
The Spectroscopic Variations of the FU Orionis Object V960 Mon
Authors: Takagi Yuhei , Honda Satoshi , Arai Akira , Morihana Kumiko , Takahashi Jun , Oasa Yumiko , Itoh Yoichi 
Published: February 2018

Abstract
We present the results of the spectroscopic monitoring of the FU Orionis type star V960 Mon. Spectroscopic variations of an FU Orionis type star will provide valuable information of its physical nature and the mechanism of the outburst. We conducted medium-resolution (R ∼ 10000) spectroscopic observations of V960 Mon with the 2 m Nayuta telescope at the Nishi-Harima Astronomical Observatory, from 2015 January to 2017 January, for 53 nights in total. We focused on Hα line and nearby atomic lines, and we detected the strength variations in both absorption and emission lines. The observed variation in the equivalent width of the absorption lines corresponds to a decrease in effective temperature and increase in surface gravity. These variations were likely to originate from the luminosity fading of the accretion disk due to the decrease in mass accretion rate.
A Fast Radio Burst Search Method for VLBI Observation
Authors: Liu Lei , Tong Fengxian , Zheng Weimin , Zhang Juan , Tong Li 
Published: February 2018

Abstract
We introduce the cross-spectrum-based fast radio burst (FRB) search method for Very Long Baseline Interferometer (VLBI) observation. This method optimizes the fringe fitting scheme in geodetic VLBI data post-processing, which fully utilizes the cross-spectrum fringe phase information and therefore maximizes the power of single-pulse signals. Working with cross-spectrum greatly reduces the effect of radio frequency interference compared with using auto-power spectrum. Single-pulse detection confidence increases by cross-identifying detections from multiple baselines. By combining the power of multiple baselines, we may improve the detection sensitivity. Our method is similar to that of coherent beam forming, but without the computational expense to form a great number of beams to cover the whole field of view of our telescopes. The data processing pipeline designed for this method is easy to implement and parallelize, which can be deployed in various kinds of VLBI observations. In particular, we point out that VGOS observations are very suitable for FRB search.
The Complex Morphology of the Young Disk MWC 758: Spirals and Dust Clumps around a Large Cavity
Authors: Boehler Y. , Ricci L. , Weaver E. , Isella A. , Benisty M. , Carpenter J. , Grady C. , Shen Bo-Ting , Tang Ya-Wen , Perez L. 
Published: February 2018

Abstract
We present Atacama Large Millimeter Array observations at an angular resolution of 0.″1–0.″2 of the disk surrounding the young Herbig Ae star MWC 758. The data consist of images of the dust continuum emission recorded at 0.88 millimeter, as well as images of the 13CO and C18O J = 3–2 emission lines. The dust continuum emission is characterized by a large cavity of roughly 40 au in radius which might contain a mildly inner warped disk. The outer disk features two bright emission clumps at radii of ∼47 and 82 au that present azimuthal extensions and form a double-ring structure. The comparison with radiative transfer models indicates that these two maxima of emission correspond to local increases in the dust surface density of about a factor 2.5 and 6.5 for the south and north clumps, respectively. The optically thick 13CO peak emission, which traces the temperature, and the dust continuum emission, which probes the disk midplane, additionally reveal two spirals previously detected in near-IR at the disk surface. The spirals seen in the dust continuum emission present, however, a slight shift of a few au toward larger radii and one of the spirals crosses the south dust clump. Finally, we present different scenarios to explain the complex structure of the disk.
Absence of Reflection Features in NuSTAR Spectra of the Luminous Neutron Star X-Ray Binary GX 5–1
Authors: Homan Jeroen , Steiner James F. , Lin Dacheng , Fridriksson Joel K. , A. Remillard Ronald , Miller Jon M. , Ludlam Renee M. 
Published: February 2018

Abstract
We present NuSTAR observations of the luminous neutron star low-mass X-ray binary (NS LMXB) and Z source GX 5−1. During our three observations made with separations of roughly two days, the source traced out an almost complete Z track. We extract spectra from the various branches and fit them with a continuum model that has been successfully applied to other Z sources. Surprisingly, and unlike most of the (luminous) NS-LMXBs observed with NuSTAR, we do not find evidence for reflection features in any of the spectra of GX 5−1. We discuss several possible explanations for the absence of reflection features. Based on a comparison with other accreting neutron star systems, and given the high luminosity of GX 5−1 (∼1.6–2.3 times the Eddington luminosity, for a distance of 9 kpc), we consider a highly ionized disk the most likely explanation for the absence of reflection features in GX 5−1.
Ubiquitous and Continuous Propagating Disturbances in the Solar Corona
Authors: Morgan Huw , Hutton Joseph 
Published: February 2018

Abstract
A new processing method applied to Atmospheric Imaging Assembly/Solar Dynamic Observatory observations reveals continuous propagating faint motions throughout the corona. The amplitudes are small, typically 2% of the background intensity. An hour’s data are processed from four AIA channels for a region near disk center, and the motions are characterized using an optical flow method. The motions trace the underlying large-scale magnetic field. The motion vector field describes large-scale coherent regions that tend to converge at narrow corridors. Large-scale vortices can also be seen. The hotter channels have larger-scale regions of coherent motion compared to the cooler channels, interpreted as the typical length of magnetic loops at different heights. Regions of low mean and high time variance in velocity are where the dominant motion component is along the line of sight as a result of a largely vertical magnetic field. The mean apparent magnitude of the optical velocities are a few tens of km s−1, with different distributions in different channels. Over time, the velocities vary smoothly between a few km s−1 to 100 km s−1 or higher, varying on timescales of minutes. A clear bias of a few km s−1 toward positive x-velocities is due to solar rotation and may be used as calibration in future work. All regions of the low corona thus experience a continuous stream of propagating disturbances at the limit of both spatial resolution and signal level. The method provides a powerful new diagnostic tool for tracing the magnetic field, and to probe motions at sub-pixel scales, with important implications for models of heating and of the magnetic field.