Large-Scale User Modeling with Recurrent Neural Networks for Music Discovery on Multiple Time Scales

The amount of content on online music streaming platforms is immense, and most users only access a tiny fraction of this content. Recommender systems are the application of choice to open up the collection to these users. Collaborative filtering has the disadvantage that it relies on explicit ratings, which are often unavailable, and generally disregards the temporal nature of music consumption. On the other hand, item co-occurrence algorithms, such as the recently introduced word2vec-based recommenders, are typically left without an effective user representation. In this paper, we present a new approach to model users through recurrent neural networks by sequentially processing consumed items, represented by any type of embeddings and other context features. This way we obtain semantically rich user representations, which capture a user's musical taste over time. Our experimental analysis on large-scale user data shows that our model can be used to predict future songs a user will likely listen to, both in the short and long term.Comment: Author pre-print version, 20 pages, 6 figures, 4 table

Outcomes of conservatively managed coracoid fractures in wild birds in the United Kingdom

Coracoid fractures are a frequent presentation in wild birds, commonly due to collisions with motor vehicles, windows, or other obstacles such as pylons. Despite this, there are few literature reports of outcomes, and those published consist of small numbers of animals, with conflicting results when comparing conservative management with surgical intervention. Outcomes of 232 adult wild birds in the United Kingdom (UK), surviving more than 48 hours after admission, with only closed unilateral coracoid fractures confirmed on radiography were retrospectively analysed. There was a high success rate for conservative management, with 75% (95% confidence interval of 69-80%, n=174/232) of all birds successfully released back to the wild. The proportion of raptors successfully returned to the wild was even higher at 97% (95% CI 85-99%, n=34/35). A statistically significant difference of 26% (95% CI of 18-34%, Fishers exact test p<0.001, Z=6.08) was demonstrated, when comparing the raptor outcomes (97% success, n=34/35) to the non-raptor outcomes (71%, n=140/198). The median time in captive care until released back to the wild was 30 days (95% CI 27-33 days). Conservative management of coracoid fractures in wild birds in the UK, and in particular in raptors, appears to result in good outcomes. The approach is low cost and non-invasive, in contrast to surgery, and is recommended as the first line approach of choice in these cases

Poverty and inequality in real-world schizophrenia: a national study

BackgroundSchizophrenia has high socioeconomic impact among severe psychiatric disorders.AimsTo explore clinician-reported and patient-reported inequities between patients under the poverty threshold vs. the others.Method916 patients consecutively recruited in 10 national centers received a comprehensive standardized evaluation of illness severity, addictions and patient-reported outcomes.Results739 (80.7%) of the patients were classified in the poverty group. This group had poorer objective illness outcomes (lower positive, negative, cognitive, excitement/aggressive and self-neglect symptoms and lifetime history of planned suicide) in multivariate analyses. While they had similar access to treatments and psychotherapy, they had lower access to socially useful activities, couple’s life, housing and parenthood. They had also more disturbed metabolic parameters. On the contrary, the poverty group reported better self-esteem. No significant difference for depression, risky health behavior including addictions and sedentary behavior was found.InterpretationThe equity in access to care is attributed to the French social system. However, mental and physical health remain poorer in these patients, and they still experience poor access to social roles independently of illness severity and despite healthcare interventions. These patients may have paradoxically better self-esteem due to decreased contact with society and therefore lower stigma exposure (especially at work). Schizophrenia presents itself as a distinct impoverished population concerning health-related outcomes and social integration, warranting focus in public health initiatives and improved treatment, including tailored interventions, collaborative care models, accessible mental health services, housing support, vocational training and employment support, community integration, education and awareness, research and data collection, culturally competent approaches, and long-term support

Original use of a direct injection high efficiency nebulizer for the standardization of liquid fuels spray flames

International audienceIt is of practical importance to lead laboratory-scale experiments allowing a better understanding of the impact of commercial fuels composition on the formation of combustion residues such as soot particles. To this end, a hybrid burner has been designed recently to burn high-speed sprays of small liquid fuel droplets. It consists of a Holthui

Stratégie d'amélioration de la modélisation de l'interaction lumière-agrégats de suie

La métrologie des aérosols ainsi que la modélisation de leurs propriétés radiatives reposent sur notre capacité à modéliser l’interaction lumière-particules (détermination de leurs sections efficaces d’absorption et de diffusion). La théorie de Mie joue parfaitement ce rôle pour des particules sphériques mais n’est pas adaptée aux particules de type agrégats fractals comme les particules de suie. La théorie Rayleigh-Debye-Gans for Fractal Aggregates a été développée pour tenir compte de la morphologie spécifique des agrégats de suie en considérant leur « petite » dimension relativement à la lumière visible. Mais cette théorie repose sur certaines hypothèses simplificatrices (notamment l’absence de couplage optique interne entre les sphérules primaires) conduisant à des erreurs parfois importantes qu’il convient de réduire. Pour améliorer cette théorie RDG-FA et proposer des termes correctifs, il est nécéssaire de mieux comprendre comment le couplage optique impacte l’évaluation des sections efficaces. Pour répondre à cet enjeu, le CORIA a développé une stratégie en trois étapes :-Production d’agrégats virtuels à morphologie réaliste, prenant en compte le recouvrement des sphérules et l’évolution des conditions thermodynamiques au sein d’une flamme (couplage à la CFD),-Détermination du champ électrique au sein de ces particules en résolvant de façon rigoureuse les équations de Maxwell (usage de l’approche discrète dipolaire),-Interprétation du champ électrique local à l’aide de l’outil phasoriel afin d’aboutir à des termes correctifs de la théorie RDG-FA.Cette présentation illustrera ces différentes étapes et fera l’état d’avancement de ce projet et dressera les perspectives de ce travail ainsi que son impact potentiel, par exemple pour la métrologie LIDAR des aérosols carbonés

ON THE IMPACT OF THE INTERNAL COUPLING ON FRACTAL AGGREGATES STRUCTURE FACTORS

International audienceAngular light scattering by aerosol particles, including complex particles such as fractal aggregates, can give access to the size and morphology through an in-situ approach. For this purpose, the angular scattering signal must be processed by a theory that provides a structure factor, which takes into account particle shape. Such a function is accurately determined for X-rays or for transparent objects in the visible range since the assumption of no internal coupling is fairly well respected. However, for some materials such as fractal soot aggregates, the internal coupling is suspected to modify the morphological and size dependence of the structure factor. The objective of this work is to understand and quantify such a deviation from the internal electric field analysis using a phasor approach

Assessing the limits of Rayleigh-Debye-Gans theory: Phasor analysis of a bisphere

International audienceRayleigh–Debye–Gans (RDG) theory is a commonly used approximation for light scattering and absorption by nanoparticles in the visible spectrum. The aim of this study is to advance our understanding for the origin of empirically observed deviations between accurate calculations of forward scattering and the absorption cross-sections and those predicted by RDG. For this purpose, we investigate the internal electric field within bi-spherical nanoparticles in several cases. The fixed-size constituent spheres of the bispheres are either separated or overlapped and are investigated using the discrete dipole approximation (DDA). To study the internal electric fields, we apply a phasor approach, which provides a semi-graphical way to understand the deviation of the forward scattering (A) and that of the absorption cross section (h) with respect to the RDG. The phasor approach reveals the influence of the bisphere orientation, absorption function E(m), scattering function F(m) and wavelength. It is observed that RDG tends to overestimate the forward scattering, i.e., A<1, as well as absorption h<1 for larger size parameters, and thus, shorter wavelengths. At the opposite limit, a decreasing absorption function E(m) leads to RDG underestimating the true scattered intensity. An explanation for this effect is a competition between the non-uniformity of the internal electric field and the phase shift of the phasors, leading to different results than those predicted by RDG and the amount of dipoles scattering in-phase

Electromagnetic coupling and determination of the structure factor of fractal aggregates

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Accounting for multiple scattering effects for the evaluation of absorption and scattering cross sections

International audienceAerosols such as soot are a matter of concern in our daily life. Due to their impact on human healthbut also on global warming, their characterization is of extremely high relevance. In this context,extensive work has been done to characterize soot particles by optical techniques because suchapproaches enable an in-situ determination. These techniques essentially rely on the attenuationof the light (LOSA), on the scattering properties (Angular Light Scattering) or on their thermalbehaviour after laser heating (LII). In any cases, the signals are interpreted based on modelsrequiring precise light-particles theories in order to express the absorption and scattering crosssections. For nano-aerosols as soot, the Rayleigh-Debye-Gans (RDG) approximation for fractalaggregates (FA) is frequently used essentially due to its simplicity since it provides a simpleanalytical expression of the scattering and absorption cross sections. However, this approximationrelies on two strong assumptions. First, the monomers composing the aggregate behave asRayleigh spheres, i.e., they are small enough compared to the wavelength and transparentenough to make the phase shift negligible. Second, it is supposed that there is no electromagneticcoupling between the monomers (internal multiple-scattering), i.e., each one sees only the incidentlight and not the light scattered by its neighbours.Many studies have compared rigorous solutions with RDG-FA ones and observed importantdiscrepancies. Indeed, RDG-FA can lead to errors up to 45% on the predicted forward scattering[1, 2] and optical determination of the fractal dimension can be overestimated by a factor up to10% [3]. Also, impact on LII measurements has been shown to be potentially important [4].Nevertheless, the precise underlying mechanisms leading to these discrepancies were not well understood and thus, until now, no models where proposed to improve RDG-FA theory regarding the internal coupling effects.The present communication aims to show to the LII and soot communities the recent advances made on this topic which were achieved by the use of the phasor approach which enables a comprehensive description of the internal electric field and its link with corrections to bring to RDGFA. The internal coupling effects will be first illustrated for a pair of monomers [5] followed by fractal aggregates [6]. Correction factors will be proposed for absorption and forward scattering. Recent advances concerning the impact of internal coupling on scattering structure factor will be also presented

MISE EN EVIDENCE DE L’AUTO-ABSORPTION ET DU COUPLAGE INTERNE AU SEIN DES AGREGATS FRACTALS

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