4,026 research outputs found

    Mars Orbiter Laser Altimeter: Experiment summary after the first year of global mapping of Mars

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    The Mars Orbiter Laser Altimeter (MOLA), an instrument on the Mars Global Surveyor spacecraft, has measured the topography, surface roughness, and 1.064-μm reflectivity of Mars and the heights of volatile and dust clouds. This paper discusses the function of the MOLA instrument and the acquisition, processing, and correction of observations to produce global data sets. The altimeter measurements have been converted to both gridded and spherical harmonic models for the topography and shape of Mars that have vertical and radial accuracies of ~1 m with respect to the planet's center of mass. The current global topographic grid has a resolution of 1/64° in latitude × 1/32° in longitude (1 × 2 km^2 at the equator). Reconstruction of the locations of incident laser pulses on the Martian surface appears to be at the 100-m spatial accuracy level and results in 2 orders of magnitude improvement in the global geodetic grid of Mars. Global maps of optical pulse width indicative of 100-m-scale surface roughness and 1.064-μm reflectivity with an accuracy of 5% have also been obtained

    Exploring the Impact of Third-Party Web Tracking on the Healthcare Providers’ Business Value

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    Organizations worldwide have been widely utilizing Internet and networking technologies to reach out the potential customers and positively impact its business outcomes. By signaling its quality- and behavior-related characteristics to online users, hospitals, are able to reduce information asymmetry and positively impact the hospital selection process. To facilitate the signaling process, many commonly rely on the third-party web tracking (TPWT) technologies. This study seeks to answer if the benefits of online engagement though TPWT are substantial enough to outweigh the potential risks associated with it. The preliminary results indicate: (1) web tracking significantly impacts the business value; and (2) its direction and magnitude vary depending on the tracker type (i.e., the impact of ad networks is negative (-18%), and that of customer engagement and website analytics is positive (25% and 55%, respectively)

    SU(2) reductions in N=4 multidimensional supersymmetric mechanics

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    We perform an su(2) Hamiltonian reduction in the bosonic sector of the su(2)-invariant action for two free (4, 4, 0) supermultiplets. As a result, we get the five dimensional N=4 supersymmetric mechanics describing the motion of an isospin carrying particle interacting with a Yang monopole. We provide the Lagrangian and Hamiltonian descriptions of this system. Some possible generalizations of the action to the cases of systems with a more general bosonic action, a four-dimensional system which still includes eight fermionic components, and a variant of five-dimensional N=4 mechanics constructed with the help of the ordinary and twisted N=4 hypermultiplets were also considered.Comment: 11 pages, LaTeX file, no figures; 3 references added, minor correction

    Peritoneal metastases in colorectal cancer

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    Peritoneal carcinomatosis (PC) is a common evolution of cancer of the gastrointestinal tract, and has been traditionally regarded as a terminal disease with short median survival. During the last 20 years, due to its favourable oncologic results, a new loco-regional therapeutic approach, combining cytoreductive surgery with intra-operative intraperitoneal chemotherapy has achieved an important development. After liver metastatic disease, peritoneal carcinomatosis is the second most frequent cause of death in colorectal cancer patient is defined as a stage IV tumour which prognosis is the worst. The extent of peritoneal carcinomatosis is, however, difficult for assessment preoperatively, and precise evaluation is most often performed during surgical exploration. Cytoreductive surgery associated with chemotherapy for the treatment of peritoneal carcinomatosis should be performed in young patients with limited and resectable carcinomatosis, in specialized institutions involved in the management of peritoneal surface malignancies

    Practical Deep Stereo (PDS): Toward applications-friendly deep stereo matching

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    End-to-end deep-learning networks recently demonstrated extremely good perfor- mance for stereo matching. However, existing networks are difficult to use for practical applications since (1) they are memory-hungry and unable to process even modest-size images, (2) they have to be trained for a given disparity range. The Practical Deep Stereo (PDS) network that we propose addresses both issues: First, its architecture relies on novel bottleneck modules that drastically reduce the memory footprint in inference, and additional design choices allow to handle greater image size during training. This results in a model that leverages large image context to resolve matching ambiguities. Second, a novel sub-pixel cross- entropy loss combined with a MAP estimator make this network less sensitive to ambiguous matches, and applicable to any disparity range without re-training. We compare PDS to state-of-the-art methods published over the recent months, and demonstrate its superior performance on FlyingThings3D and KITTI sets

    Heat increments and oxidation enthalpies of (Y,Pr,Gd)BaCo2O6-δ double perovskites

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    Complex oxides (Y,Gd,Pr)BaCo2O6-δ attracts researchers’ attention due to it are promising materials for cathodes for solid state fuel cells. However, fundamental thermodynamic properties of these double perovskites such as heat increments, heat capacity and enthalpy of oxidation are not investigated so far. Powder samples of (Y,Gd,Pr)BaCo2O6-δ were prepared using glycerol–nitrate technique. Phase composition of investigated double perovskites was controlled by X-ray powder diffraction. Then samples with composition GdBaCo2O5.51, PrBaCo2O5.77, YBaCo2O5.33 were prepared by slowly cooling with speed rate 100 K/h, whereas sample YBaCo2O5.0 was prepared by annealing at 1373 K and quenching. Enthalpy increments of all as-prepared samples were measured by high temperature drop-calorimetry method on the SETARAM MHTC 96 calorimeter. Since YBaCo2O6-δ is stable only above 1123 K in air, calorimetry measurements were carried out in region 1123≤T, K≤1323. Oxidation enthalpies of (Gd,Pr)BaCo2O6-δ were measured by means of DSC sensors of MHTC 96 calorimeter at 1173K. Oxidation enthalpy of YBaCo2O6-δ was calculated from heat increments measurements. Obtained data allow us to calculate a heat capacity dependency from temperature for these compounds. Acknowledgement: This study was supported by the Russian Foundation for Basic Research (Grant No. 18-33-20243)

    The Power of Collective Insight: Harnessing the Wisdom of the Crowd for Digital Auction Success

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    During the COVID-19 pandemic, online auction markets gained significant importance for their efficient and transparent handling of the shift in economic activity. Renowned digital car auction platform Bring a Trailer (BaT) experienced remarkable growth, with its revenue reaching $828 million in 2020. This study investigates the factors contributing to BaT\u27s success, focusing on the role of its unique community comment feature, which leverages the collective intelligence of its users, known as wisdom of the crowd (WOC) in IS literature. Analyzing a dataset of 13,451 car listings, the study explores how WOC elements such as information quality and user identity impact auction performance. The analysis reveals that helpful WOC content positively influences auction outcomes, reducing information asymmetry and increasing market efficiency. The impact of WOC contributor reputations, however, showed less consistent results. These findings are relevant for stakeholders in the automotive market, providing insights to inform decision-making in online auction markets
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