1,113 research outputs found

    Global and Seasonal Scintillation Morphology in the Equatorial Region Derived from ROCSAT-1 In-situ Data

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    The global/seasonal distributions of the scintillation occurrence rate are obtained from the in-situ density measurement of the ROCSAT-1 using a modified procedure reported by Wernik et al. (2007). A least-squares curve fitting in the optimal trust region is used to obtain the spectral slope for the density irregularity structure and the outer scale of the scintillation. The distribution of the S4 index for the weak scintillation (S4 < 0.3) is almost identical to that of the equatorial irregularity distribution reported in the literature. However, as the scintillation becomes stronger (0.3 < S4 < 0.6), the latitudinal distribution moves to the equatorial ionization anomaly (EIA) region. In addition, the distributions of the outer scale values that are useful for the study of the physical evolution of the irregularity structure are also obtained. The occurrence distribution of scintillation activity with several parameters such as dip-latitude, longitude, local time, solar activity, and geomagnetic activity during different seasons are presented and discussed in this paper

    Force correlations in molecular and stochastic dynamics

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    A molecular gas system in three dimensions is numerically studied by the energy conserving molecular dynamics (MD). The autocorrelation functions for the velocity and the force are computed and the friction coefficient is estimated. From the comparison with the stochastic dynamics (SD) of a Brownian particle, it is shown that the force correlation function in MD is different from the delta-function force correlation in SD in short time scale. However, as the measurement time scale is increased further, the ensemble equivalence between the microcanonical MD and the canonical SD is restored. We also discuss the practical implication of the result.Comment: 9 pages, 4 figures and Computer Physics Communcations (in press

    Refinement treatment of nasal bone fracture: A 6-year study of 329 patients

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    SummaryBackgroundThe reliability of X-ray radiography for diagnosing nasal bone fractures (NBFs) remains controversial. Recent studies show that, for determining the orientation and location of the displaced/depressed fracture, nasal sonography is as accurate as facial computed tomography. This retrospective study compared conductor-assisted nasal sonography (CANS) to conventional diagnostic tools and reported subjective patient satisfaction and discomfort after closed reduction combined with tube technique.MethodsThis retrospective study reports the results of 329 refinement treatments for nasal bone fracture (including 199 men and 130 women) performed from 2005 to 2011. All patients were assessed with CANS and completed a survey immediately prior to removing the packing. Questionnaires were adapted from the nasal obstruction symptom evaluation (NOSE) scale.ResultsThe study found that CANS has a 97.2% rate of accuracy in diagnosing NBF. The visual analog scale scores of nasal obstruction, nasal congestion, sleep disturbance, trouble breathing, and inability to move air through the nose were analyzed. The experimental group scores were significantly different from the control group for all scores (p < 0.001).ConclusionCompared to conventional methods, CANS is more accurate for detecting NBF. We recommend its use as an alternative tool for diagnosing a nasal fracture. Because the tube technique balances pressure between the nasopharynx and middle ear during swallowing, patient comfort is enhanced. Application of these modifications can improve accuracy in diagnosing NBF and can improve the quality of NBF treatment

    Detecting Variability in Massive Astronomical Time-series Data. II. Variable Candidates in the Northern Sky Variability Survey

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    We present variability analysis of data from the Northern Sky Variability Survey (NSVS). Using the clustering method, which defines variable candidates as outliers from large clusters, we cluster 16,189,040 light curves having data points at more than 15 epochs as variable and non-variable candidates in 638 NSVS fields. Variable candidates are selected depending on how strongly they are separated from the largest cluster and how rarely they are grouped together in eight-dimensional space spanned by variability indices. All NSVS light curves are also cross-correlated with IRAS , AKARI, Two Micron All Sky Survey, Sloan Digital Sky Survey (SDSS), and GALEX objects, as well as known objects in the SIMBAD database. The variability analysis and cross-correlation results are provided in a public online database, which can be used to select interesting objects for further investigation. Adopting conservative selection criteria for variable candidates, we find about 1.8 million light curves as possible variable candidates in the NSVS data, corresponding to about 10% of our entire NSVS sample. Multi-wavelength colors help us find specific types of variability among the variable candidates. Moreover, we also use morphological classification from other surveys such as SDSS to suppress spurious cases caused by blending objects or extended sources due to the low angular resolution of the NSVS.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98631/1/1538-3881_143_3_65.pd

    Second-trimester Maternal Serum Quadruple Test for Down Syndrome Screening: A Taiwanese Population-based Study

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    SummaryObjectiveTo assess the usefulness of quadruple test screening for Down syndrome in Taiwan.Materials and MethodsMaternal serum concentrations of a-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and inhibin A were measured in 21,481 pregnant women from 15 to 20 weeks of gestation.ResultsOf the 21,481 women, 977 returned values greater than the high-risk cut-off value (1 in 270). Most of these women (86.2%) decided to have an invasive procedure for genetic diagnosis. Nine cases of Down syndrome and 19 cases of other chromosomal anomalies were detected prenatally. Two children with Down syndrome were diagnosed after delivery even though a low estimated risk was determined following the quadruple test. The detection rate was 81.8% (nine out of 11 cases), with a 4.4% false-positive rate. The median multiple of the median value for a-fetoprotein, human chorionic gonadotropin, unconjugated estriol and inhibin A were 0.87, 2.34, 0.77 and 2.16, respectively, in affected cases.ConclusionThis is the first study of the quadruple test for Down syndrome in a Chinese population. Our findings suggested that the second-trimester quadruple test provides an effective screening tool for Down syndrome in Taiwan

    Are Primetime Diets Congruent With Dietary Recommendations? Content Analyses of Food Advertisements in the United States, China, and Singapore

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    Despite public programs to promote healthy eating among populations in developed and developing countries, the increase in obesity as a result of poor dietary patterns continues to persist. As food advertising has been implicated for contributing to this global health challenge, this study aims to provide empirical evidence on food advertising in a broader global context, across economically and culturally different nations. We conducted a large scale content analysis of the types of food advertised on primetime television in the United States, China, and Singapore, which resulted in the collection of 1,008 television hours. Using the dietary blue2376s proposed by the health authorities as the applied framework, the study compared the types of food advertised against the dietary parameters. Findings showed that despite differences in economic development and cultures, food advertised on primetime television across three countries are incongruent with dietary recommendations. The study offers insights on how misaligned and out of sync food advertising and commercial interests are from government health policies. Implications of findings to encourage healthy eating among populations worldwide are discussed

    巨額土砂匯入對和社溪河相演變之影響

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    Macro-sediment impulses induced by particular typhoons and rainstorms are the main reason for serious sediment disasters in the Heshe River. For example, the sediment input during Typhoon Morakot in 2009 which accounted for 95.8% of the annual sediment discharge is the most serious of these disasters. Since Typhoon Morakot, the sediment input has decreased, as there have been less serious typhoons and rainstorms, thus, transforming the river morphology from a braided river into meandering river. In addition, river bends and topographical notches restrain sediment from moving downstream and store it in these locations. These factors have indirectly increased the erosion density of the river banks by 2.5 to 10.5 times.特定之颱風及豪雨事件為和社溪集水區內巨額土砂進入河道造成相關土砂災害之主 要因素;尤以2009 年莫拉克颱風其間之輸砂量,佔該年總輸砂量之95.8%最為嚴重。然而,莫拉克颱風過後並無發生規模較大之颱風及豪雨事件,因此進入和社溪之土砂漸減,使得因土砂堆積造成之辮狀河川逐漸走向蜿蜒。此外,河川轉折點跟隘口處都會抑止土砂往下游運移並使土砂集中於此處,間接造成河岸淘刷密度增加2.5 至10.5 倍

    Discovery of Lorentz-violating Weyl fermion semimetal state in LaAlGe materials

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    We report theoretical and experimental discovery of Lorentz-violating Weyl fermion semimetal type-II state in the LaAlGe class of materials. Previously type-II Weyl state was predicted in WTe2 materials which remains unrealized in surface experiments. We show theoretically and experimentally that LaAlGe class of materials are the robust platforms for the study of type-II Weyl physics.Comment: This paper reports theoretical prediction and experimental discovery together. A detailed theoretical paper describing the topology of the full family of X(Lanthanides)AlGe materials will follow. Other related papers can be found at http://physics.princeton.edu/zahidhasangroup/index_WS.htm
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