An Exploratory Study of Black Male College Athletes' Perceptions on Race and Athlete Activism

The authors conducted a quantitative study of six black male athletes at American universities. Using the intellectual paradigm of critical race theory, they analyze the athletes' views on race and the role of athlete activism in their generation

Ultrafast Acousto-Plasmonics in Gold Nanoparticles Superlattice

We report the investigation of the generation and detection of GHz coherent acoustic phonons in plasmonic gold nanoparticles superlattices (NPS). The experiments have been performed from an optical femtosecond pump-probe scheme across the optical plasmon resonance of the superlattice. Our experiments allow to estimate the collective elastic response (sound velocity) of the NPS as well as an estimate of the nano-contact elastic stiffness. It appears that the light-induced coherent acoustic phonon pulse has a typical in-depth spatial extension of about 45 nm which is roughly 4 times the optical skin depth in gold. The modeling of the transient optical reflectivity indicates that the mechanism of phonon generation is achieved through ultrafast heating of the NPS assisted by light excitation of the volume plasmon. These results demonstrate how it is possible to map the photon-electron-phonon interaction in subwavelength nanostructures

A trans-diagnostic perspective on obsessive-compulsive disorder

© Cambridge University Press 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.Progress in understanding the underlying neurobiology of obsessive-compulsive disorder (OCD) has stalled in part because of the considerable problem of heterogeneity within this diagnostic category, and homogeneity across other putatively discrete, diagnostic categories. As psychiatry begins to recognize the shortcomings of a purely symptom-based psychiatric nosology, new data-driven approaches have begun to be utilized with the goal of solving these problems: specifically, identifying trans-diagnostic aspects of clinical phenomenology based on their association with neurobiological processes. In this review, we describe key methodological approaches to understanding OCD from this perspective and highlight the candidate traits that have already been identified as a result of these early endeavours. We discuss how important inferences can be made from pre-existing case-control studies as well as showcasing newer methods that rely on large general population datasets to refine and validate psychiatric phenotypes. As exemplars, we take 'compulsivity' and 'anxiety', putatively trans-diagnostic symptom dimensions that are linked to well-defined neurobiological mechanisms, goal-directed learning and error-related negativity, respectively. We argue that the identification of biologically valid, more homogeneous, dimensions such as these provides renewed optimism for identifying reliable genetic contributions to OCD and other disorders, improving animal models and critically, provides a path towards a future of more targeted psychiatric treatments.Peer reviewedFinal Published versio

Elaboration de surfaces nano/micro-structurées pour limiter l’adhésion de micro-organismes

Avec plus d’un million de dispositifs posés par an dans le monde, l’utilisation des chambres implantables s’est maintenant généralisée pour le traitement de certains cancers. Constituées d’un réservoir de quelques dixièmes de microlitres, le plus souvent en titane, relié à un cathéter dont l’extrémité est placée dans une veine à fort débit, ils permettent de délivrer un traitement de chimiothérapie avec un confort augmenté pour le patient. Ces dispositifs permettent aussi le cas échéant d’apporter une nutrition parentérale. Cette dernière utilisation provoque de nombreuses infections, qui conduisent dans la plupart des cas au retrait du dispositif. Afin de réduire le risque de contamination, il est donc nécessaire de mieux comprendre les facteurs favorisant l’adhérence des micro-organismes (bactéries et levures) dans ces dispositifs médicaux invasifs et leur colonisation ultérieure. Dans le cadre du projet régional MAT-INNO, nos travaux de recherche visent à mieux comprendre l’impact des propriétés de surface (en termes de topographie, hydrophobicité et fonctionnalisation) sur l’adhésion de bactéries et de levures. En agissant sur les propriétés physiques et/ou chimiques de surface, nous espérons réduire les capacités d\u27adhérence des micro-organismes et ainsi limiter le risque d\u27infection. Les études actuelles sont réalisées sur des substrats de silicium sur lesquels est déposée une couche mince nanométrique d’oxyde de titane. Nos efforts portent, dans un premier temps, sur la maîtrise de la topographie de surface à l’échelle nanométrique et micrométrique, notamment par la mise au point de procédés de fabrication reproductibles. L’utilisation de la pulvérisation cathodique sur les supports de silicium ultra-lisses permet d’obtenir des surfaces d’oxyde de titane ayant des rugosités inférieures au nanomètre. De plus, l’attaque du silicium par l’hydroxyde de potassium permet de modifier la topographie des surfaces avant le dépôt de films minces d’oxyde de titane. Nous présentons sur le poster les résultats obtenus récemment par microscopie à force atomique et par microscopie électronique à balayage sur les différents types de surface. L’analyse des courbes de réflectivité des rayons X nous a permis de déterminer précisément l’épaisseur des films déposés et de suivre les modifications de la composition chimique suivant les paramètres appliqués

Improved flow-based formulations for the skiving stock problem

Thanks to the rapidly advancing development of (commercial) MILP software and hardware components, pseudo-polynomial formulations have been established as a powerful tool for solving cutting and packing problems in recent years. In this paper, we focus on the one-dimensional skiving stock problem (SSP), where a given inventory of small items has to be recomposed to obtain a maximum number of larger objects, each satisfying a minimum threshold length. In the literature, different modeling approaches for the SSP have been proposed, and the standard flow-based formulation has turned out to lead to the best trade-off between efficiency and solution time. However, especially for instances of practically meaningful sizes, the resulting models involve very large numbers of variables and constraints, so that appropriate reduction techniques are required to decrease the numerical efforts. For that reason, this paper introduces two improved flow-based formulations for the skiving stock problem that are able to cope with much larger problem sizes. By means of extensive experiments, these new models are shown to possess significantly fewer variables as well as an average better computational performance compared to the standard arcflow formulation

Self-assembled monolayers of bisphosphonates: Influence of side chain steric hindrance

Bisphosphonates form self-assembled monolayers (SAMs) spontaneously on stainless steel, silicon, and titanium oxidized surfaces. We used contact angle measurements, atomic force microscopy, and X-ray reflectivity analysis to study the formation of SAMs on a model surface of ultraflat titanium (rms=0.2 nm). The results were extended to standard materials (mechanically polished titanium, stainless steel, and silicon) and showed that water-soluble bisphosphonic perfluoropolyether can easily form SAMs, with 100% surface coverage and a layer thickness of less than 3 nm. Hydrophobic (water contact angle >110° on stainless steel or titanium) and lipophobic (methylene iodide contact angle >105° on titanium) properties are discussed in terms of industrial applications

Extrasolar planets and brown dwarfs around A--F type stars. VIII. A giant planet orbiting the young star HD113337

In the frame of the search for extrasolar planets and brown dwarfs around early-type main-sequence stars, we present the detection of a giant planet around the young F-type star HD113337. We estimated the age of the system to be 150 +100/-50 Myr. Interestingly, an IR excess attributed to a cold debris disk was previously detected on this star. The SOPHIE spectrograph on the 1.93m telescope at Observatoire de Haute-Provence was used to obtain ~300 spectra over 6 years. We used our SAFIR tool, dedicated to the spectra analysis of A and F stars, to derive the radial velocity variations. The data reveal a 324.0 +1.7/-3.3 days period that we attribute to a giant planet with a minimum mass of 2.83 +- 0.24 Mjup in an eccentric orbit with e=0.46 +- 0.04. A long-term quadratic drift, that we assign to be probably of stellar origin, is superimposed to the Keplerian solution.Comment: 7 pages, 4 figure

Synthesis of hollow vaterite CaCO(3) microspheres in supercritical carbon dioxide medium

We here describe a rapid method for synthesizing hollow core, porous crystalline calcium carbonate microspheres composed of vaterite using supercritical carbon dioxide in aqueous media, without surfactants. We show that the reaction in alkaline media rapidly conducts to the formation of microspheres with an average diameter of 5 mu m. SEM, TEM and AFM observations reveal that the microspheres have a hollow core of around 0.7 mu m width and are composed of nanograins with an average diameter of 40 nm. These nanograins are responsible for the high specific surface area of 16 m(2) g(-1) deduced from nitrogen absorption/desorption isotherms, which moreover confers an important porosity to the microspheres. We believe this work may pave the way for the elaboration of a biomaterial with a large potential for therapeutic as well as diagnostic applications

A Markovian event-based framework for stochastic spiking neural networks

In spiking neural networks, the information is conveyed by the spike times, that depend on the intrinsic dynamics of each neuron, the input they receive and on the connections between neurons. In this article we study the Markovian nature of the sequence of spike times in stochastic neural networks, and in particular the ability to deduce from a spike train the next spike time, and therefore produce a description of the network activity only based on the spike times regardless of the membrane potential process. To study this question in a rigorous manner, we introduce and study an event-based description of networks of noisy integrate-and-fire neurons, i.e. that is based on the computation of the spike times. We show that the firing times of the neurons in the networks constitute a Markov chain, whose transition probability is related to the probability distribution of the interspike interval of the neurons in the network. In the cases where the Markovian model can be developed, the transition probability is explicitly derived in such classical cases of neural networks as the linear integrate-and-fire neuron models with excitatory and inhibitory interactions, for different types of synapses, possibly featuring noisy synaptic integration, transmission delays and absolute and relative refractory period. This covers most of the cases that have been investigated in the event-based description of spiking deterministic neural networks