737 research outputs found

    LCrowdV: Generating Labeled Videos for Simulation-based Crowd Behavior Learning

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    We present a novel procedural framework to generate an arbitrary number of labeled crowd videos (LCrowdV). The resulting crowd video datasets are used to design accurate algorithms or training models for crowded scene understanding. Our overall approach is composed of two components: a procedural simulation framework for generating crowd movements and behaviors, and a procedural rendering framework to generate different videos or images. Each video or image is automatically labeled based on the environment, number of pedestrians, density, behavior, flow, lighting conditions, viewpoint, noise, etc. Furthermore, we can increase the realism by combining synthetically-generated behaviors with real-world background videos. We demonstrate the benefits of LCrowdV over prior lableled crowd datasets by improving the accuracy of pedestrian detection and crowd behavior classification algorithms. LCrowdV would be released on the WWW

    Signal yields, energy resolution, and recombination fluctuations in liquid xenon

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    This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon re- combination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2-16 keV with 3^3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.Comment: 11 pages, 12 figures, 3 table

    Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches

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    The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of 238^{238}Ue_{e}~<<1.6~mBq/kg, 238^{238}Ul_{l}~<<0.09~mBq/kg, 232^{232}The_{e}~=0.28±0.03=0.28\pm 0.03~mBq/kg, 232^{232}Thl_{l}~=0.25±0.02=0.25\pm 0.02~mBq/kg, 40^{40}K~<<0.54~mBq/kg, and 60^{60}Co~<<0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of 0.160±0.0010.160\pm0.001(stat)±0.030\pm0.030(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle Physic

    Laparoscopic Ventral Mesh Fixation in Patients with Pelvic Organ Prolapse

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    Pelvic organ prolapse (POP) is a condition with a high incidence rate and often creates difficulties in surgical coloproctology and gynecology. The aim of this study was to evaluate the effectiveness of laparoscopic ventral reticular sacrocolporectopexy and sacrorectopexi in women and men with POP, respectively. This study was conducted at the Educational-Surgical Clinic of Azerbaijan Medical University and Department of Surgery of the Faculty of Medicine of Ankara University (2016-2019) on 21 patients with POP (15 women and 6 men). Results of diagnostics and surgical treatment of POP were studied with preferences towards endoscopic, radiation, and functional methods. The surgical methods used in these patients included laparoscopic fixation methods (sacrocolpopexy, sacrocolporectopexy) of protruding organs (uterus, vaginal vault/vaginal cuff, rectum) and simultaneous vaginal (colporrhaphy, colpolevatoroplasty, vaginal plastic surgery) and proctological surgeries (circulatory resection, hemorrhoidectomy, sphincteroplasty). The findings demonstrated that the most progressive POP mostly occurred in women of premenopausal age and during menopause. Based on the results of the long-term evaluation of the surgical treatment (6-12 months), the rates of recurrence of prolapse and complications were low (up to 4.8% and 9.5%, respectively) with favorable long-term functional results,  such as a decrease in the degree of fecal incontinence and constipation, observed in the evaluation. Due to the concomitant weakness of the ligamentous apparatus of the pelvic floor in these patients, there is the need for intra-abdominal apical support of organs. In conclusion, that laparoscopic sacrocolpopexy in women and sacrorectopexy in men are reliable surgical method to treat POP. However, specific skills need to be acquired by both gynecologist and coloproctologist to be able to do these laparoscopic surgery techniques

    A Map of Dielectric Heterogeneity in a Membrane Protein: the Hetero-Oligomeric Cytochrome b 6 f Complex

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    The cytochrome b6f complex, a member of the cytochrome bc family that mediates energy transduction in photosynthetic and respiratory membranes, is a hetero-oligomeric complex that utilizes two pairs of b-hemes in a symmetric dimer to accomplish trans-membrane electron transfer, quinone oxidation–reduction, and generation of a proton electrochemical potential. Analysis of electron storage in this pathway, utilizing simultaneous measurement of heme reduction, and of circular dichroism (CD) spectra, to assay heme–heme interactions, implies a heterogeneous distribution of the dielectric constants that mediate electrostatic interactions between the four hemes in the complex. Crystallographic information was used to determine the identity of the interacting hemes. The Soret band CD signal is dominated by excitonic interaction between the intramonomer b-hemes, bn and bp, on the electrochemically negative and positive sides of the complex. Kinetic data imply that the most probable pathway for transfer of the two electrons needed for quinone oxidation–reduction utilizes this intramonomer heme pair, contradicting the expectation based on heme redox potentials and thermodynamics, that the two higher potential hemes bn on different monomers would be preferentially reduced. Energetically preferred intramonomer electron storage of electrons on the intramonomer b-hemes is found to require heterogeneity of interheme dielectric constants. Relative to the medium separating the two higher potential hemes bn, a relatively large dielectric constant must exist between the intramonomer b-hemes, allowing a smaller electrostatic repulsion between the reduced hemes. Heterogeneity of dielectric constants is an additional structure–function parameter of membrane protein complexes
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