193 research outputs found

    Predicting the Perceptual Demands of Urban Driving with Video Regression

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    To drive safely requires perceiving vast amounts of rapidly changing visual information. This can exhaust our limited perceptual capacity and lead to cases of 'looking but failing to see', reportedly the third largest contributing factor to road traffic accidents. In the present work we use a 3D convolutional neural network to model the perceptual demand of varied driving situations. To validate the method we introduce a new labelled dataset of approximately 2300 videos of driving in Brussels and California

    Impact of frequent apheresis blood donation on bone density: A prospective,longitudinal, randomized, controlled trial

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    Background Blood for transfusion is lifesaving and essential to many elements of modern medical practice. The global blood supply relies on volunteer blood donors. Apheresis is increasingly used to collect blood and requires anticoagulant to prevent extracorporeal coagulation. Citrate, the standard apheresis anticoagulant, chelates ionized calcium with consequent perturbations of serum calcium, parathyroid hormone, vitamin D, and markers of bone remodeling in donors. Cross-sectional studies of bone mineral density (BMD) among apheresis donors exhibit conflicting results. Methods The longitudinal, randomized, controlled ALTRUYST trial (NCT02655055) was undertaken to determine whether BMD declined following high frequency apheresis blood donation over 1 year. The study was powered at 80% to detect the primary outcome of a 3% decline in BMD. Subjects new to apheresis agreed to make ≥20 apheresis donations in a one-year period and were randomized to treatment (high frequency apheresis) or control (no apheresis). Dual-energy x-ray absorptiometry was performed before and after participation. Two-sided t-test and multivariable logistic regression were used to assess outcomes. Findings Mean lumbar spine BMD did not change during the study among control donors (−0.002 g/cm2, 95%CI [−0.020, 0.016], p = 0.78), or among donors in the apheresis arm (mean change = 0.007 g/cm2, 95%CI [−0.005, 0.018], p = 0.24). Mean total hip BMD did not change for control donors (mean change = 0.002 g/cm2, 95%CI [−0.006, 0.009], p = 0.63) or apheresis donors (−0.004 g/cm2, 95%CI [−0.10, 0.002], p = 0.16). Tests for differences in proportions of donors with change in BMD exceeding the least significant change at the lumbar spine in either a positive [8 apheresis (31%), 4 control (27%), p = 0.78] or negative direction [4 apheresis (15%), 5 control (33%)] were statistically non-significant (p = 0.18). Proportional increases [0 apheresis (0%), 1 control (7%), p = 0.18] and decreases [3 apheresis (12%), 1 control (14%)] were also not significantly different at the total hip (p = 0.61). Interpretation ALTRUYST is the first longitudinal trial to demonstrate that apheresis blood collection guidelines in the United States adequately protect the skeletal health of male volunteer blood donors

    Influence of Edge Effects on Laser-Induced Surface Displacement of Opaque Materials by Photothermal Interferometry

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    We demonstrate the influence of edge effects on the photothermal-induced phase shift measured by a homodyne quadrature laser interferometer and compare the experiments with rigorous theoretical descriptions of thermoelastic surface displacement of metals. The finite geometry of the samples is crucial in determining how the temperature is distributed across the material and how this affects the interferometer phase shift measurements. The optical path change due to the surface thermoelastic deformation and thermal lens in the surrounding air is decoded from the interferometric signal using analytical and numerical tools. The boundary/edge effects are found to be relevant to properly describe the interferometric signals. The tools developed in this study provide a framework for the study of finite size effects in heat transport in opaque materials and are applicable to describe not only the phase shift sensed by the interferometer but also to contribute to the photothermal-based technologies employing similar detection mechanisms

    On the origin of negative target currents during laser ablation of polyethylene

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    The exposure of a target to a focused laser beam results in the occurrence of a time-varying current between the target itself and the grounded vacuum chamber. This current is composed by three distinct phases, namely the ignition phase, in which the laser pulse drives the electron emission, while electrons coming from the ground through the target holder balance the positive charge generated on the target. The active phase appears at post-pulse times and it is characterized by the presence of peaked structures in the time-resolved current, representing characteristics of the target composition. Lastly, the afterglow phase is determined by a current of electrons flowing from the target to the ground. During the active phase of the target current resulting from polymers ablation with an UV KrF laser, negative target current peaks are observed, whose origin is still unknown. We investigate the dependence of these current structures on the dimensions of the target, using ultra-high molecular weight polyethylene disks of different thickness

    METSTOR: A GIS to look for potential CO2 storage zones in France

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    AbstractThe METSTOR project offers a methodology to look for potentially interesting CO2 storage areas in France at the initial stage, before the “site selection” step. Our tool, embodied in a Geographic Information System, is based on an interactive map of CO2 storage capacities. Other relevant information layers are included. The geographic layers are complemented with a series of online technical notices. It seems to be the first open online GIS that offers policy makers, businesses and the public at large an integrated access to that necessary information. Our prototype, limited mainly to the Paris Basin, is released online at www.metstor.fr

    Technical Design Report for the PANDA Solenoid and Dipole Spectrometer Magnets

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    This document is the Technical Design Report covering the two large spectrometer magnets of the PANDA detector set-up. It shows the conceptual design of the magnets and their anticipated performance. It precedes the tender and procurement of the magnets and, hence, is subject to possible modifications arising during this process.Comment: 10 pages, 14MB, accepted by FAIR STI in May 2009, editors: Inti Lehmann (chair), Andrea Bersani, Yuri Lobanov, Jost Luehning, Jerzy Smyrski, Technical Coordiantor: Lars Schmitt, Bernd Lewandowski (deputy), Spokespersons: Ulrich Wiedner, Paola Gianotti (deputy

    Role of Operon aaoSo-mutT in Antioxidant Defense in Streptococcus oligofermentans

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    Previously, we have found that an insertional inactivation of aaoSo, a gene encoding L-amino acid oxidase (LAAO), causes marked repression of the growth of Streptococcus oligofermentans. Here, we found that aaoSo and mutT, a homolog of pyrophosphohydrolase gene of Escherichia coli, constituted an operon. Deletion of either gene did not impair the growth of S. oligofermentans, but double deletion of both aaoSo and mutT was lethal. Quantitative PCR showed that the transcript abundance of mutT was reduced for 13-fold in the aaoSo insertional mutant, indicating that gene polarity derived from the inactivation of aaoSo attenuated the expression of mutT. Enzymatic assays were conducted to determine the biochemical functions of LAAO and MutT of S. oligofermentans. The results indicated that LAAO functioned as an aminoacetone oxidase [47.75 nmol H2O2 (min·mg protein)–1]; and MutT showed the pyrophosphohydrolase activity, which removed mutagens such as 8-oxo-dGTP. Like paraquat, aaoSo mutations increased the expression of SOD, and addition of aminoacetone (final concentration, 5 mM) decreased the mutant’s growth by 11%, indicating that the aaoSo mutants are under ROS stress. HPLC did reveal elevated levels of cytoplasmic aminoacetone in both the deletion and insertional gene mutants of aaoSo. Electron spin resonance spectroscopy showed increased hydroxyl radicals in both types of aaoSo mutant. This demonstrated that inactivation of aaoSo caused the elevation of the prooxidant aminoacetone, resulting the cellular ROS stress. Our study indicates that the presence of both LAAO and MutT can prevent endogenous metabolites-generated ROS and mutagens. In this way, we were able to determine the role of the aaoSo-mutT operon in antioxidant defense in S. oligofermentans
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