682 research outputs found

    Dynamic Matrix Factorization with Priors on Unknown Values

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    Advanced and effective collaborative filtering methods based on explicit feedback assume that unknown ratings do not follow the same model as the observed ones (\emph{not missing at random}). In this work, we build on this assumption, and introduce a novel dynamic matrix factorization framework that allows to set an explicit prior on unknown values. When new ratings, users, or items enter the system, we can update the factorization in time independent of the size of data (number of users, items and ratings). Hence, we can quickly recommend items even to very recent users. We test our methods on three large datasets, including two very sparse ones, in static and dynamic conditions. In each case, we outrank state-of-the-art matrix factorization methods that do not use a prior on unknown ratings.Comment: in the Proceedings of 21st ACM SIGKDD Conference on Knowledge Discovery and Data Mining 201

    Pattern measurements of a low-sidelobe horn antenna

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    The techniques and results of power pattern measurements of a corrugated horn antenna designed for low sidelobes are reported. The power pattern was measured to levels 90 dB below the main beam maximum in both the E- and H-planes. The measured patterns were found to be in good agreement with predictions from existing theory for the performance of corrugated scalar feeds

    Intra-seasonal Variability of Near-bottom Current in the Halmahera Sea

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    The secondary entry portal of the Indonesian Throughflow (ITF) from the Pacific to Indian Oceans is considered to be via the Halmahera Sea (HS). However, few ITF studies have been done within the passage. This motivated the Internal Tides and Mixing in the Indonesian Througflow (INDOMIX) program to conduct direct measurements of currents and its variability across the eastern path of the ITF. This study focused on the intra-seasonal variability of near-bottom current in HS (129°E, 0°S), its origin and correlation with surface zonal winds and sea surface height over the equatorial Pacific Ocean. The result showed a strong northwestward mean flow with velocity exceeding 40 cm/s, which represented the current-following topography with the northwest orientation. Meridional current component was much stronger than the zonal component. The energy of power spectral density (PSD) of the current peaked on 14-days and 27-days periods. The first period was presumably related to the tidal oscillation, but the latter may be associated with surface winds perturbation. Furthermore, cross-PSD revealed a significant coherency between the observed currents and the surface zonal winds in the central equatorial Pacific zonal winds (180°E-160°W), which corroborates westward propagation of intra-seasonal sea surface height signals along the 5°S with its mean phase speeds of 50 cm/s, depicting the low-latitude westward Rossby waves on intra-seasonal band

    Mental Health Carve-Outs: Effects and Implications

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    To control the rise in expenditures and to increase access to mental health and substance abuse (MH/SA) services, a growing number of employers and states are implementing a “carve-out.” Under this arrangement, the sponsor separates insurance benefits by disease or condition, service category, or population and contracts separately for the management of care and/or associated risks. A carve-out allows a unique set of managed care techniques to be applied to a subset of particularly costly or complex benefits. This article describes various carve-out models, discusses the potential advantages and disadvantages of a full carve-out, and summarizes recent public and private sector research regarding the strategy’s effects on access and use, cost savings and shifting, and quality of care. It concludes by discussing approaches to the assessment and monitoring of the processes and outcomes associated with a MH/SA carve-out.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68797/2/10.1177_107755879905600203.pd

    Square-wave voltammetric determination of primaquine in urine using a multi-walled carbon nanotube modified electrode

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    The electrochemical process involving primaquine was studied at a glassy carbon (GC) electrode modified with multi-walled carbon nanotubes (MWCNT). The GC/MWCNTs electrode promoted an intense oxidation peak for primaquine, improving signal when compared to the one observed using bare GC as electrode. Besides the increasing in active electrode area, the MWCNTs seemed to provide faster electron transfer. The linear analytical response for primaquine, in the concentration range from 0.1 to 5.0 μmol L−1, was achieved on a supporting electrolyte consisting of Britton-Robinson buffer (0.02 mol L−1; pH 7.00) and KCl (0.25 mol L−1). The quantitative assay using square-wave voltammetry was performed by successive additions of standard into the electrochemical cell, containing the sample, with instrumental limit of detection (LOD) of 7.3 μg L−1 (28 nmol L−1). A procedure involving liquid-liquid extraction and thin-layer chromatography provided selectivity and pre-concentration required for the determination of traces of primaquine in urine samples (LOD of the method of 146 ng L−1). Recoveries in urine samples were statistically similar to the one achieved by HPLC

    Protocorm Like Bodies (PLBs) dendrobium orchid “Gatton Sunray”

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    The Dendrobium Orchid Gatton Sunray is a hybrid orchid of Dendrobium pulchellum × Dendrobium illustre. A study was aimed to find the best type of medium and type of banana for the multiplication of Protocorm-Like Bodies (PLBs) of this orchid. This research was conducted from February to September 2020 at the Plant Tissue Culture Laboratory, Faculty of Agriculture, The University of Bengkulu. Treatments included type of media and cultivar of ripe banana fruit, added as source of organic complex, consisted of 4 cultivars, namely Ambon Curup, Kepok, Tanduk and Mas. Ripe bananas were mashed and added to the in vitro medium as much as 50 g.L-1. Types of media consist of Murashige and Skoog (MS), ½ Doses of Murashige and Skoog (MS) media, and Complex of fertilizer media. The results showed that the ½ MS medium added with 50 g.L-1 cv. Kepok fruit produced the greatest multiplication (11.8 PLBs per jar), the best growth of PLBs, including the greatest PLBs number (28.5 PLBs per jar), the heaviest fresh weight (1.30 g per jar) and the longest PLBs (2.56 cm)

    Effects of air pollution and the introduction of the London Low Emission Zone on the prevalence of respiratory and allergic symptoms in schoolchildren in East London: a sequential cross-sectional study

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    The adverse effects of traffic-related air pollution on children’s respiratory health have been widely reported, but few studies have evaluated the impact of traffic-control policies designed to reduce urban air pollution. We assessed associations between traffic-related air pollutants and respiratory/allergic symptoms amongst 8–9 year-old schoolchildren living within the London Low Emission Zone (LEZ). Information on respiratory/allergic symptoms was obtained using a parent-completed questionnaire and linked to modelled annual air pollutant concentrations based on the residential address of each child, using a multivariable mixed effects logistic regression analysis. Exposure to traffic-related air pollutants was associated with current rhinitis: NOx (OR 1.01, 95% CI 1.00–1.02), NO2 (1.03, 1.00–1.06), PM10 (1.16, 1.04–1.28) and PM2.5 (1.38, 1.08–1.78), all per μg/m3 of pollutant, but not with other respiratory/allergic symptoms. The LEZ did not reduce ambient air pollution levels, or affect the prevalence of respiratory/allergic symptoms over the period studied. These data confirm the previous association between traffic-related air pollutant exposures and symptoms of current rhinitis. Importantly, the London LEZ has not significantly improved air quality within the city, or the respiratory health of the resident population in its first three years of operation. This highlights the need for more robust measures to reduce traffic emissions

    Higher education analytics: New trends in program assessments

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    © 2018, Springer International Publishing AG, part of Springer Nature. End of course evaluations technologies can provide critical analytics that can be used to improve the academic outcomes of almost any university. This paper presents key findings from a study conducted on more than twenty different academic degree-programs, regarding their use of end of course evaluation technology. Data was collected from an online survey instrument, in-depth interviews with academic administrators, and two case studies, one in the US and another in the UAE. The study reveals new trends including sectioning and categorization; questions standardization and benchmarking; alignment with key performance indicators and key learning outcomes; and grouping by course, program outcome, program, college, etc. in addition to those vertical structures, higher education institutions are vertically examining a specific question(s) across
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