Last 7 days     Results 661-680 of 59947.   29 30 31 32 33 34 35 36 37 38 39   A new asteroseismic diagnostic for internal rotation in γ Doradus starsOuazzani, Rhita-Maria; Salmon, Sébastien ; Antoci, V. et alin Monthly Notices of the Royal Astronomical Society (2017), 465With four years of nearly-continuous photometry from Kepler, we are finally in a good position to apply asteroseismology to $\gamma$ Doradus stars. In particular several analyses have demonstrated the ... [more ▼]With four years of nearly-continuous photometry from Kepler, we are finally in a good position to apply asteroseismology to $\gamma$ Doradus stars. In particular several analyses have demonstrated the possibility to detect non-uniform period spacings, which have been predicted to be directly related to rotation. In the present work, we define a new seismic diagnostic for rotation in $\gamma$ Doradus stars that are too rapidly rotating to present rotational splittings. Based on the non uniformity of their period spacings, we define the observable $\Sigma$ as the slope of the period spacing when plotted as a function of period. We provide a one-to-one relation between this observable $\Sigma$ and the internal rotation, which applies widely in the instability strip of $\gamma$ Doradus stars. We apply the diagnostic to a handful of stars observed by Kepler. Thanks to g-modes in $\gamma$ Doradus stars, we are now able to determine the internal rotation of stars on the lower main sequence, which is still not possible for Sun-like stars. [less ▲]Detailed reference viewed: 13 (2 ULg) Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1Wheatley, Peter J.; Louden, Tom; Bourrier, Vincent et alin Monthly Notices of the Royal Astronomical Society (2017), 465We present an XMM-Newton X-ray observation of TRAPPIST-1, which is an ultracool dwarf star recently discovered to host three transiting and temperate Earth-sized planets. We find the star is a relatively ... [more ▼]We present an XMM-Newton X-ray observation of TRAPPIST-1, which is an ultracool dwarf star recently discovered to host three transiting and temperate Earth-sized planets. We find the star is a relatively strong and variable coronal X-ray source with an X-ray luminosity similar to that of the quiet Sun, despite its much lower bolometric luminosity. We find L_x/L_bol=2-4x10^-4, with the total XUV emission in the range L_xuv/L_bol=6-9x10^-4. Using a simple energy-limited model we show that the relatively close-in Earth-sized planets, which span the classical habitable zone of the star, are subject to sufficient X-ray and EUV irradiation to significantly alter their primary and perhaps secondary atmospheres. Understanding whether this high-energy irradiation makes the planets more or less habitable is a complex question, but our measured fluxes will be an important input to the necessary models of atmospheric evolution. [less ▲]Detailed reference viewed: 9 (1 ULg) Clinical settings in knee osteoarthritis: Pathophysiology guides treatmentHerrero-Beaumont, Gabriel; Roman-Blas, Jorge A; Bruyère, Olivier et alin Maturitas (2017), 96Osteoarthritis (OA) is the most common chronic joint disorder and its prevalence increases rapidly during midlife. Complex interactions of genetic alterations, sex hormone deficit, and aging with ... [more ▼]Osteoarthritis (OA) is the most common chronic joint disorder and its prevalence increases rapidly during midlife. Complex interactions of genetic alterations, sex hormone deficit, and aging with mechanical factors and systemic inflammation-associated metabolic syndrome lead to joint damage. Thus, the expression of a clinical phenotype in the early stages of OA relies on the main underlying pathway and predominant joint tissue involved at a given time. Moreover, OA often coexists with other morbidities in the same patient, which in turn condition the OA process. In this scenario, an appropriate identification of clinical phenotypes, especially in the early stages of the disease, may optimize the design of individualized treatments in OA. An ESCEO-EUGMS (European Union Geriatric Medicine Society) working group has recently suggested possible patient profiles in OA. Hereby, we propose the existence of 4 clinical phenotypes – biomechanical, osteoporotic, metabolic and inflammatory – whose characterization would help to properly stratify patients with OA in clinical trials or studies. Further research in this field is warranted. [less ▲]Detailed reference viewed: 15 (1 ULg) Quantitative determination of salbutamol sulfate impurities using achiral supercritical fluid chromatographyDispas, Amandine ; Desfontaine, Vincent; Andri, Bertyl et alin Journal of Pharmaceutical & Biomedical Analysis (2017), 134In the last years, supercritical fluid chromatography has largely been acknowledged as a singular and performing technique in the field of separation sciences. Recent studies highlighted the interest of ... [more ▼]In the last years, supercritical fluid chromatography has largely been acknowledged as a singular and performing technique in the field of separation sciences. Recent studies highlighted the interest of SFC for the quality control of pharmaceuticals, especially in the case of the determination of the active pharmaceutical ingredient (API).Nevertheless, quality control requires also the determination of impurities. The objectives of the present work were to i) demonstrate the interest of SFC as a reference technique for the determination of impurities in salbutamol sulfate API and ii) to propose an alternative to a reference HPLC method from the European Pharmacopeia (EP) involving ionpairing reagent. Firstly, a screening was carried out to select the most adequate and selective stationary phase. Secondly, in the context of robust optimization strategy, the method was developed using design space methodology. The separation of salbutamol sulfate and related impurities was achieved in 7 minutes, which is seven times faster than the LC-UV method proposed by European Pharmacopeia (total run time of 50 minutes). Finally, full validation using accuracy profile approach was successfully achieved for the determination of impurities B, D, F and G in salbutamol sulfate raw material. The validated dosing range covered 50 to 150 % of the targeted concentration (corresponding to 0.3 % concentration level), LODs close to 0.5 μg/mL were estimated. The SFC method proposed in this study could be presented as a suitable fast alternative to EP LC method for the quantitative determination of salbutamol impurities. [less ▲]Detailed reference viewed: 12 (2 ULg) Les acteurs: introductionDubois, Christophe in Hendrick, Aude; Musin, Aude; Rousseaux, Xavier (Eds.) et al Les mots de la justice (2017)Detailed reference viewed: 10 (0 ULg) VictimeDubois, Christophe ; Martin, Danielin Hendrick, Aude; Musin, Aude; Rousseaux, Xavier (Eds.) et al Les mots de la justice (2017)Detailed reference viewed: 14 (0 ULg) Justice restauratriceDubois, Christophe in Hendrick, Aude; Musin, Aude; Rousseaux, Xavier (Eds.) et al Les mots de la justice (2017)Detailed reference viewed: 9 (0 ULg) De Actoren: inleidingDubois, Christophe in Hendrick, Aude; Musin, Aude; Rousseaux, Xavier (Eds.) et al Het verhaal van justitie (2017)Detailed reference viewed: 11 (0 ULg) SlachtofferDubois, Christophe ; Martin, Danielin Hendrick, Aude; Musin, Aude; Rousseaux, Xavier (Eds.) et al Het verhaal van justitie (2017)Detailed reference viewed: 8 (0 ULg) Herstelgerichte JustitieDubois, Christophe in Hendrick, Aude; Musin, Aude; Rousseaux, Xavier (Eds.) et al Het verhaal van justitie (2017)Detailed reference viewed: 9 (0 ULg) Learning from blind tests: Determining the function of experimental grinding stones through use-wear and residue analysisHayes, Elspeth H.; Cnuts, Dries ; Lepers, Christian et alin Journal of Archaeological Science: Reports (2017), 11Abstract Blind tests provide an objective means to evaluate the accuracy of functional interpretations based on the presence of use-wear and residue traces on stone tools. Previous blind tests have ... [more ▼]Abstract Blind tests provide an objective means to evaluate the accuracy of functional interpretations based on the presence of use-wear and residue traces on stone tools. Previous blind tests have highlighted interpretive errors commonly associated with use-wear and residue analyses leading to significant methodological developments in each of the respective fields. While a number of blind tests have been performed on flaked stone tools, only a single blind test has been published for use-wear on grinding tools. We present the results of a two-part blind test performed on 15 experimental grinding implements that were used in a controlled setting, designed to evaluate the relative importance of residue analysis for determining the worked material (1) when contextual information is available and (2) when contextual information is absent. We argue that use-wear and residue analyses are successful procedures to identify the use of grinding stones, and that residue analysis may be a particularly valuable means for determining the worked material on tools that have insufficient use-wear development. We suggest that residues should be sufficiently abundant to infer use, if we are to avoid the potential confusion caused by contamination. [less ▲]Detailed reference viewed: 18 (2 ULg) The importance of open data and software: Is energy research lagging behind?Pfenninger, Stefan; DeCariolis, Joseph; Hirth, Lion et alin Energy Policy (2017)Energy policy often builds on insights gained from quantitative energy models and their underlying data. As climate change mitigation and economic concerns drive a sustained transformation of the energy ... [more ▼]Energy policy often builds on insights gained from quantitative energy models and their underlying data. As climate change mitigation and economic concerns drive a sustained transformation of the energy sector, transparent and well-founded analyses are more important than ever. We assert that models and their associated data must be openly available to facilitate higher quality science, greater productivity through less duplicated effort, and a more effective science-policy boundary. There are also valid reasons why data and code are not open: ethical and security concerns, unwanted exposure, additional workload, and institutional or personal inertia. Overall, energy policy research ostensibly lags behind other fields in promoting more open and reproducible science. We take stock of the status quo and propose actionable steps forward for the energy research community to ensure that it can better engage with decision-makers and continues to deliver robust policy advice in a transparent and reproducible way. [less ▲]Detailed reference viewed: 28 (2 ULg) Approximate Bayes Optimal Policy Search using Neural NetworksCastronovo, Michaël ; François-Lavet, Vincent ; Fonteneau, Raphaël et alin Proceedings of the 9th International Conference on Agents and Artificial Intelligence (ICAART 2017) (2017, February)Bayesian Reinforcement Learning (BRL) agents aim to maximise the expected collected rewards obtained when interacting with an unknown Markov Decision Process (MDP) while using some prior knowledge. State ... [more ▼]Bayesian Reinforcement Learning (BRL) agents aim to maximise the expected collected rewards obtained when interacting with an unknown Markov Decision Process (MDP) while using some prior knowledge. State-of-the-art BRL agents rely on frequent updates of the belief on the MDP, as new observations of the environment are made. This offers theoretical guarantees to converge to an optimum, but is computationally intractable, even on small-scale problems. In this paper, we present a method that circumvents this issue by training a parametric policy able to recommend an action directly from raw observations. Artificial Neural Networks (ANNs) are used to represent this policy, and are trained on the trajectories sampled from the prior. The trained model is then used online, and is able to act on the real MDP at a very low computational cost. Our new algorithm shows strong empirical performance, on a wide range of test problems, and is robust to inaccuracies of the prior distribution. [less ▲]Detailed reference viewed: 129 (14 ULg) New data on the Mesozoic radiation of chelonioidsScavezzoni, Isaure ; Fischer, Valentin Poster (2017, February)Detailed reference viewed: 13 (1 ULg) Megaloolithid dinosaur eggs: scrambled parataxonomy and nesting strategiesJentgen, Benjamin ; Stein, Koen; Fischer, Valentin Poster (2017, February)Detailed reference viewed: 13 (1 ULg) La notion d’attention virtuelle dans la philosophie médiévaleDubouclez, Olivier Scientific conference (2017, February)Detailed reference viewed: 12 (0 ULg) Chez Froidmont au Nord : lectures polyphoniques d’une quête identitaireBaiwir, Esther ; Adams, Juliette; Demonchaux, Chloé et alin Tortue verte. Revue en ligne des littératures francophones (2017)Detailed reference viewed: 11 (0 ULg) Voyage[s] à travers le thymusGeenen, Vincent in Science et Culture (2017), (465), 14-15Detailed reference viewed: 15 (0 ULg) An App-based Algorithmic Approach for Harvesting Local and Renewable Energy Using Electric VehiclesDubois, Antoine; Wehenkel, Antoine; Fonteneau, Raphaël et alin Proceedings of the 9th International Conference on Agents and Artificial Intelligence (ICAART 2017) (2017, February)The emergence of electric vehicles (EVs), combined with the rise of renewable energy production capacities, will strongly impact the way electricity is produced, distributed and consumed in the very near ... [more ▼]The emergence of electric vehicles (EVs), combined with the rise of renewable energy production capacities, will strongly impact the way electricity is produced, distributed and consumed in the very near future. This position paper focuses on the problem of optimizing charging strategies for a fleet of EVs in the context where a significant amount of electricity is generated by (distributed) renewable energy. It exposes how a mobile application may offer an efficient solution for addressing this problem. This app can play two main roles. Firstly, it would incite and help people to play a more active role in the energy sector by allowing photovoltaic (PV) panel owners to sell their electrical production directly to consumers, here the EVs’ agents. Secondly, it would help distribution system operators (DSOs) or transmission system operators (TSOs) to modulate more efficiently the load by allowing them to influence EV charging behaviour in real time. Finally, the present paper advocates for the introduction of a two-sided market-type model between EV drivers and electricity producers. [less ▲]Detailed reference viewed: 367 (49 ULg) Residential heat pump as flexible load for direct control service with parametrized duration and rebound effectGeorges, Emeline ; Cornélusse, Bertrand ; Ernst, Damien et alin Applied Energy (2017), 187This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service consists of a power modulation, upward or downward, that is ... [more ▼]This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service consists of a power modulation, upward or downward, that is activated at a given time period over a fixed number of periods. The service modulation is relative to an optimized baseline that minimizes the energy costs. The load modulation is directly followed by a constrained rebound effect, consisting of a delay time with no deviations from the baseline consumption and a payback time to return to the baseline state. The potential amount of modulation and the constrained rebound effect are computed by solving mixed integer linear problems. Within these problems, the thermal behavior of the building is modeled by an equivalent thermal network made of resistances and lumped capacitances. Simulations are performed for different sets of buildings typical of the Belgian residential building stock and are presented in terms of achievable modulation amplitude, deviations from the baseline and associated costs. A cluster of one hundred ideal buildings, corresponding to retrofitted freestanding houses, is then chosen to investigate the influence of each parameter defined within the service. Results show that with a set of one hundred heat pumps, a load aggregator could expect to harvest mean modulation amplitudes of up to 138 kW for an upward modulation and up to 51 kW for a downward modulation. The obtained values strongly depend on the proposed flexibility service. For example, they can decrease down to 2.6 kW and 0.4 kW, respectively, if no rebound effect is allowed. [less ▲]Detailed reference viewed: 265 (25 ULg)