38 research outputs found

    Music Recommendations in Hyperbolic Space: An Application of Empirical Bayes and Hierarchical Poincar\'e Embeddings

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    Matrix Factorization (MF) is a common method for generating recommendations, where the proximity of entities like users or items in the embedded space indicates their similarity to one another. Though almost all applications implicitly use a Euclidean embedding space to represent two entity types, recent work has suggested that a hyperbolic Poincar\'e ball may be more well suited to representing multiple entity types, and in particular, hierarchies. We describe a novel method to embed a hierarchy of related music entities in hyperbolic space. We also describe how a parametric empirical Bayes approach can be used to estimate link reliability between entities in the hierarchy. Applying these methods together to build personalized playlists for users in a digital music service yielded a large and statistically significant increase in performance during an A/B test, as compared to the Euclidean model

    Modelling baryonic feedback for survey cosmology

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    Observational cosmology in the next decade will rely on probes of the distribution of matter in the redshift range between 0<z<30<z<3 to elucidate the nature of dark matter and dark energy. In this redshift range, galaxy formation is known to have a significant impact on observables such as two-point correlations of galaxy shapes and positions, altering their amplitude and scale dependence beyond the expected statistical uncertainty of upcoming experiments at separations under 10 Mpc. Successful extraction of information in such a regime thus requires, at the very least, unbiased models for the impact of galaxy formation on the matter distribution, and can benefit from complementary observational priors. This work reviews the current state of the art in the modelling of baryons for cosmology, from numerical methods to approximate analytical prescriptions, and makes recommendations for studies in the next decade, including a discussion of potential probe combinations that can help constrain the role of baryons in cosmological studies. We focus, in particular, on the modelling of the matter power spectrum, P(k,z)P(k,z), as a function of scale and redshift, and of the observables derived from this quantity. This work is the result of a workshop held at the University of Oxford in November of 2018

    Liver Is Able to Activate NaĂŻve CD8+ T Cells with Dysfunctional Anti-Viral Activity in the Murine System

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    The liver possesses distinct tolerogenic properties because of continuous exposure to bacterial constituents and nonpathogenic food antigen. The central immune mediators required for the generation of effective immune responses in the liver environment have not been fully elucidated. In this report, we demonstrate that the liver can indeed support effector CD8+ T cells during adenovirus infection when the T cells are primed in secondary lymphoid tissues. In contrast, when viral antigen is delivered predominantly to the liver via intravenous (IV) adenovirus infection, intrahepatic CD8+ T cells are significantly impaired in their ability to produce inflammatory cytokines and lyse target cells. Additionally, intrahepatic CD8+ T cells generated during IV adenovirus infection express elevated levels of PD-1. Notably, lower doses of adenovirus infection do not rescue the impaired effector function of intrahepatic CD8+ T cell responses. Instead, intrahepatic antigen recognition limits the generation of potent anti-viral responses at both priming and effector stages of the CD8+ T cell response and accounts for the dysfunctional CD8+ T cell response observed during IV adenovirus infection. These results also implicate that manipulation of antigen delivery will facilitate the design of improved vaccination strategies to persistent viral infection

    Praziquantel Facilitates IFN-Îł-Producing CD8+ T Cells (Tc1) and IL-17-Producing CD8+ T Cells (Tc17) Responses to DNA Vaccination in Mice

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    BACKGROUND: CD8(+) cytotoxic T lymphocytes (CTLs) are crucial for eliminating hepatitis B virus (HBV) infected cells. DNA vaccination, a novel therapeutic strategy for chronic virus infection, has been shown to induce CTL responses. However, accumulated data have shown that CTLs could not be effectively induced by HBV DNA vaccination. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that praziquantel (PZQ), an anti-schistoma drug, could act as an adjuvant to overcome the lack of potent CTL responses by HBV DNA vaccination in mice. PZQ in combination with HBV DNA vaccination augmented the induction of CD8(+) T cell-dependent and HBV-specific delayed hypersensitivity responses (DTH) in C57BL/6 mice. Furthermore, the induced CD8(+) T cells consisted of both Tc1 and Tc17 subtypes. By using IFN-Îł knockout (KO) mice and IL-17 KO mice, both cytokines were found to be involved in the DTH. The relevance of these findings to HBV immunization was established in HBsAg transgenic mice, in which PZQ also augmented the induction of HBV-specific Tc1 and Tc17 cells and resulted in reduction of HBsAg positive hepatocytes. Adoptive transfer experiments further showed that PZQ-primed CD8(+) T cells from wild type mice, but not the counterpart from IFN-Îł KO or IL-17 KO mice, resulted in elimination of HBsAg positive hepatocytes. CONCLUSIONS/SIGNIFICANCE: Our results suggest that PZQ is an effective adjuvant to facilitate Tc1 and Tc17 responses to HBV DNA vaccination, inducing broad CD8(+) T cell-based immunotherapy that breaks tolerance to HBsAg

    Rubin-Euclid Derived Data Products:Initial Recommendations

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    This report is the result of a joint discussion between the Rubin and Euclid scientific communities. The work presented in this report was focused on designing and recommending an initial set of Derived Data products (DDPs) that could realize the science goals enabled by joint processing. All interested Rubin and Euclid data rights holders were invited to contribute via an online discussion forum and a series of virtual meetings. Strong interest in enhancing science with joint DDPs emerged from across a wide range of astrophysical domains: Solar System, the Galaxy, the Local Volume, from the nearby to the primaeval Universe, and cosmology

    The Evolution of Enterprise Reform in Africa: From State-Owned Enterprises to Private Participation in Infrastructure - and Back?

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    Acoustic Emissions analysis of a four-point bending test on a Reinforced Concrete beam

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    Assessment of existing structures by means of non-destructive techniques is an important research topic in modern engineering, because of its potential in estimating structural health status without introducing undesired damage. Among several recognized techniques, Acoustic Emission (AE) analysis is growing interest in the scientific community, since it can be used to detect the initiation of cracking processes, to determine cracking typology and to extract other information from the specimen. In this paper, the authors present the results of a four-point bending test on a Reinforce Concrete (RC) beam, performed at the University of Salerno. The test has been conducted according to a loading protocol characterised by several loading-unloading cycles, and both mechanical and acoustic data have been recorded. The results will be presented in terms of standard AE parameters, commonly adopted in literature, such as Felicity ratio, signal strength and cumulative signal strength, historic index and b value. It will be underlined that these parameters allow to detect interesting moments of the phenomenon (cracking onset and development) and to assess the damage of the structure

    Acoustic Emissions analysis of a four-point bending test on a Reinforced Concrete beam

    No full text
    Assessment of existing structures by means of non-destructive techniques is an important research topic in modern engineering, because of its potential in estimating structural health status without introducing undesired damage. Among several recognized techniques, Acoustic Emission (AE) analysis is growing interest in the scientific community, since it can be used to detect the initiation of cracking processes, to determine cracking typology and to extract other information from the specimen. In this paper, the authors present the results of a four-point bending test on a Reinforce Concrete (RC) beam, performed at the University of Salerno. The test has been conducted according to a loading protocol characterised by several loading-unloading cycles, and both mechanical and acoustic data have been recorded. The results will be presented in terms of standard AE parameters, commonly adopted in literature, such as Felicity ratio, signal strength and cumulative signal strength, historic index and b value. It will be underlined that these parameters allow to detect interesting moments of the phenomenon (cracking onset and development) and to assess the damage of the structure

    An Ultrasound Technique for the Characterization of the Acoustic Emission of Reinforced Concrete Beam

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    Among the various non-destructive techniques for health monitoring in structures, the Acoustic Emission (AE) is well known in scientific literature. Ultrasonic waves emitted by the creation and propagation of cracks in concrete or Reinforced Concrete specimens are usually collected by means of ultrasonic sensors. The signals must be treated in front-end readout process with preamplifiers and filters, to be able to set a proper trigger level and to cut the background noise (belonging to different frequency ranges). In addition, the post processing of the data is important to “clean up” the dataset, removing fake events, and to extract the proper information, useful for structure damage assessment. In this paper, the authors present the experimental set up and the transducers used to acquire the AE signals recorded during a four-point bending test on a RC beam. The ad hoc realized amplifier and filtering circuit used in the test are also described. Then, an example of an AE signal is also reported, in terms of frequency spectrum analysis and noise filterin
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