1,685 research outputs found

    ARMWRESTLING EXERCISE AND SHOULDER INTERNAL ROTATION STRENGTH

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    The purpose of this study was to investigate the differences in shoulder internal rotation strength between winner and loser during armwrestling. Prior to the armwrestling experiment, subjects would be tested for strength of shoulder internal rotation with 45 Ā°/sec and 60 Ā°/sec by isokinetic dynamometer. The results showed that the strength of shoulder internal rotation at angular velocity of 45Ā°/sec and 60Ā°/sec had significant difference between winner and loser (

    Site classification and Vs30 estimation of free-field TSMIP stations using the logging data of EGDT

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    The Engineering Geological Database for TSMIP (EGDT), the Taiwan Strong Motion Instrumentation Program, has been under construction by the National Center for Research on Earthquake Engineering and the Central Weather Bureau in Taiwan since 2000. Site characterization, comprising surface investigations and logging measurements, was carried out throughout the project. We provide a set of specifications and a description to help users understand the subject matter of the database. EGDT contains 469 surveyed stations, 439 of which were drilled and the logging measurements completed. Of these, 385 had logging data reaching at least 30 m, and we used these to examine and determine the most accurate extrapolation of Vs30 (the average S-wave velocity of the top 30 m of strata) for the other 54 stations with velocity profiles less than 30 m. The chosen method assumed that the bottom velocity is identical from the actual depth of the hole to a distance of 30 m, that is, the Bottom Constant Velocity (BCV) method. In order to utilize other existing boreholes which have only N values but no velocities in the future, the empirical S-wave velocity equations for seven different regions and the whole of Taiwan were evaluated by a multivariable analysis. Henceforth, for those existing boreholes which have an N profile less than 30 m, the S-wave velocity profile can first be calculated by empirical S-wave velocity equations, and then Vs30 can be estimated by reliable extrapolation. Some other studies of site classifications of TSMIP stations were compared with our results to demonstrate the necessity of reclassification. Ultimately, the Vs30 values of the 439 drilled free-field TSMIP stations were derived and the new site classification was achieved according to the Vs30-based provisions of the National Earthquake Hazards Reduction Program

    Sampling Neural Radiance Fields for Refractive Objects

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    Recently, differentiable volume rendering in neural radiance fields (NeRF) has gained a lot of popularity, and its variants have attained many impressive results. However, existing methods usually assume the scene is a homogeneous volume so that a ray is cast along the straight path. In this work, the scene is instead a heterogeneous volume with a piecewise-constant refractive index, where the path will be curved if it intersects the different refractive indices. For novel view synthesis of refractive objects, our NeRF-based framework aims to optimize the radiance fields of bounded volume and boundary from multi-view posed images with refractive object silhouettes. To tackle this challenging problem, the refractive index of a scene is reconstructed from silhouettes. Given the refractive index, we extend the stratified and hierarchical sampling techniques in NeRF to allow drawing samples along a curved path tracked by the Eikonal equation. The results indicate that our framework outperforms the state-of-the-art method both quantitatively and qualitatively, demonstrating better performance on the perceptual similarity metric and an apparent improvement in the rendering quality on several synthetic and real scenes.Comment: SIGGRAPH Asia 2022 Technical Communications. 4 pages, 4 figures, 1 table. Project: https://alexkeroro86.github.io/SampleNeRFRO/ Code: https://github.com/alexkeroro86/SampleNeRFR

    Increasing fMRI Sampling Rate Improves Granger Causality Estimates

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    Estimation of causal interactions between brain areas is necessary for elucidating large-scale functional brain networks underlying behavior and cognition. Granger causality analysis of time series data can quantitatively estimate directional information flow between brain regions. Here, we show that such estimates are significantly improved when the temporal sampling rate of functional magnetic resonance imaging (fMRI) is increased 20-fold. Specifically, healthy volunteers performed a simple visuomotor task during blood oxygenation level dependent (BOLD) contrast based whole-head inverse imaging (InI). Granger causality analysis based on raw InI BOLD data sampled at 100-ms resolution detected the expected causal relations, whereas when the data were downsampled to the temporal resolution of 2 s typically used in echo-planar fMRI, the causality could not be detected. An additional control analysis, in which we SINC interpolated additional data points to the downsampled time series at 0.1-s intervals, confirmed that the improvements achieved with the real InI data were not explainable by the increased time-series length alone. We therefore conclude that the high-temporal resolution of InI improves the Granger causality connectivity analysis of the human brain

    High-Frequency Sea Level Variations Observed by GPS Buoys Using Precise Point Positioning Technique

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    In this study, sea level variation observed by a 1-Hz Global Positioning System (GPS) buoy system is verified by comparing with tide gauge records and is decomposed to reveal high-frequency signals that cannot be detected from 6-minute tide gauge records. Compared to tide gauges traditionally used to monitor sea level changes and affected by land motion, GPS buoys provide high-frequency geocentric measurements of sea level variations. Data from five GPS buoy campaigns near a tide gauge at Anping, Tainan, Taiwan, were processed using the Precise Point Positioning (PPP) technique with four different satellite orbit products from the International GNSS Service (IGS). The GPS buoy data were also processed by a differential GPS (DGPS) method that needs an additional GPS receiver as a reference station and the accuracy of the solution depends on the baseline length. The computation shows the average Root Mean Square Error (RMSE) difference of the GPS buoy using DGPS and tide gauge records is around 3 - 5 cm. When using the aforementioned IGS orbit products for the buoy derived by PPP, its average RMSE differences are 5 - 8 cm, 8 - 13 cm, decimeter level, and decimeter-meter level, respectively, so the accuracy of the solution derived by PPP highly depends on the accuracy of IGS orbit products. Therefore, the result indicates that the accuracy of a GPS buoy using PPP has the potential to measure the sea surface variations to several cm. Finally, high-frequency sea level signals with periods of a few seconds to a day can be successfully detected in GPS buoy observations using the Ensemble Empirical Mode Decomposition (EMD) method and are identified as waves, meteotsunamis, and tides

    Risk of death in patients with post-traumatic cerebrospinal fluid leakageā€”Analysis of 1773 cases

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    AbstractBackgroundPost-traumatic cerebrospinal fluid (CSF) leakage is one of the most troublesome conditions associated with head trauma. CSF fistulae, meningitis/central nervous infection, or even death may accompany it. Few studies have discussed post-traumatic CSF leakage as a risk factor in mortality following head trauma. We conducted this cohort study to examine the issue.MethodsWe reviewed the records in the Taiwan Traumatic Brain Injury (TBI) Registry System between 1993 and 2008. The study group included patients with acute TBI and post-traumatic CSF leakage, and the control group included cases with TBI but without CSF leakage, selected randomly at a 5:1 ratio with respect to the study group. The demographic data, Glasgow Coma Scale, brain computerized tomography, association of skull fractures and intracranial lesions, and 1-year mortality rates between these two cohorts were reviewed meticulously and analyzed statistically.ResultsOf 174,236 cases, 1773 with post-traumatic CSF leakage were included in the study group, and 8865 cases in the control group. Of the total 10,638 sampled cases, 406 (3.8%) died during the 1-year follow-up period, 159 (9.0%) cases in the CSF leakages group, and 247 (2.8%) in the control group. The patients with CSF leakage had a significantly higher mortality rate within 1 year (adjusted hazard ratioĀ =Ā 1.44, pĀ <Ā 0.001) than those without. We divided the CSF leakage group into three subgroups: otorrhea (nĀ =Ā 568), rhinorrhea (nĀ =Ā 302), and tension pneumocephalus (nĀ =Ā 903). The mortality rates were 8.5% (48/568) in the otorrhea subgroup, 10.9% (33/302) in the rhinorrhea subgroup, and 8.6% (78/903) in the tension pneumocephalus subgroup. The cases with CSF rhinorrhea had a significantly higher mortality rate than the other two subgroups (pĀ <Ā 0.05). All three subgroups had significantly higher mortality rates than the control group during the 1-year follow-up period (adjusted hazard ratiosĀ =Ā 2.29, 1.35, and 1.32 in the rhinorrhea, tension pneumocephalus, and otorrhea subgroups, respectively).ConclusionPost-traumatic CSF leakages had higher mortality rates than those without CSF leakages in TBI cases, and the cases with CSF rhinorrhea had worse outcomes compared with CSF leakages with pneumocephalus or otorrhea

    Postchallenge responses of nitrotyrosine and TNF-alpha during 75-g oral glucose tolerance test are associated with the presence of coronary artery diseases in patients with prediabetes

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    <p>Abstract</p> <p>Background</p> <p>Meta-analysis has demonstrated an exponential relationship between 2-hr postchallenge hyperglycemia and coronary artery disease (CAD). Pulsatile hyperglycemia can acutely increase proinflammatory cytokines by oxidative stress. We hypothesized that postchallenge proinflammatory and nitrosative responses after 75 g oral glucose tolerance tests (75 g-OGTT) might be associated with CAD in patients without previously recognized type 2 diabetes mellitus (T2DM).</p> <p>Methods</p> <p>Serial changes of plasma glucose (PG), tumor necrosis factor-alpha (TNF-Ī±), interleukin-6 (IL-6) and nitrotyrosine levels were analyzed during 75 g-OGTT in 120 patients (81 male; age 62 Ā± 11 years) before coronary angiography. Patients were classified as normal (NGT; 42%), impaired (IGT; 34%) and diabetic (T2DM; 24%) glucose tolerance by 75 g-OGTT.</p> <p>Results</p> <p>Postchallenge hyperglycemia elicited TNF-Ī±, IL-6 and nitrotyrosine levels time-dependently, and 2-hr median levels of TNF-Ī± (7.1 versus 6.4 pg/ml; <it>P </it>< 0.05) and nitrotyrosine (1.01 versus 0.83 <it>Ī¼</it>mol/l; <it>P </it>< 0.05), but not IL-6 or PG, were significantly higher in patients with CAD in either IGT or T2DM groups. After adjusting risk factors and glucose tolerance status, 2-hr nitrotyrosine in highest quartiles (OR: 3.1, <it>P </it>< 0.05) remained an independent predictor of CAD by logistic regression analysis.</p> <p>Conclusions</p> <p>These results highlight postchallenge proinflammatory and nitrosative responses by 75 g-OGTT, rather than hyperglycemia <it>per se</it>, are associated with CAD in patients without previous recognized diabetes.</p
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