High-energy radiation from the relativistic jet of Cygnus X-3

Cygnus X-3 is an accreting high-mass X-ray binary composed of a Wolf-Rayet star and an unknown compact object, possibly a black hole. The gamma-ray space telescope Fermi found definitive evidence that high-energy emission is produced in this system. We propose a scenario to explain the GeV gamma-ray emission in Cygnus X-3. In this model, energetic electron-positron pairs are accelerated at a specific location in the relativistic jet, possibly related to a recollimation shock, and upscatter the stellar photons to high energies. The comparison with Fermi observations shows that the jet should be inclined close to the line of sight and pairs should not be located within the system. Energetically speaking, a massive compact object is favored. We report also on our investigations of the gamma-ray absorption of GeV photons with the radiation emitted by a standard accretion disk in Cygnus X-3. This study shows that the gamma-ray source should not lie too close to the compact object.Comment: 4 pages, 3 figures, Proceedings of the SF2A conference held in Marseille, 21-24 June 201

Représentations sociales et conditions de vie des personnes âgées classées malades mentales ou déficientes intellectuelles en résidence d’accueil1

Le vieillissement de la population au Québec, comme ailleurs en Occident, met aussi en évidence des personnes qui jusqu'alors étaient grandement marginalisées. C'est le cas des personnes classées malades mentales (PCMM) ou déficientes intellectuelles (PCDI) qui, jusqu'à tout récemment, vivaient pour la plupart leur vieillesse à l'ombre des institutions psychiatriques. Ces personnes ont-elles désormais trouvé, avec le programme de désinstitutionnalisation, la possibilité de vivre leur vieillesse au sein de la société ? Ce texte analyse les conditions d'intégration et les réseaux de soutien, en somme la prise en charge collective des PCDI et des PCMM vieillissantes en résidence d'accueil.The aging of the population in Québec as in the rest of the western world, brings to the fore people who until now were greatly marginalized. This is the case of mentally ill and mentally retarded elderly who until recently, lived their aging in the shadow of psychiatric institutions. Have these people now found with deinstitutionalization, the possibility of growing old within society ? This article analyses the conditions of integration and support networks, in sum a collective responsability of these aging people in nursing homes.El envejecimiento de la población en el Quebec, como en todo Occidente, evidencia claramente las personas que hasta entonces habían sido muy marginadas. Este es el caso de las personas clasificadas enfermas mentales (PCEM) o deficientes intelectuales (PCDI) quienes en su mayoría y hasta hace poco, vivían su vejez a la sombra de las instituciones psiquiátricas. A pesar de todo, con los programas de desinstitucionalización, han encontrado estas personas la posibilidad de vivir en sociedad ? Este texto analiza las condiciones de integración y las redes de apoyo, en resumen, la toma a cargo colectiva de personas PCEM y PCDI que envejecen en albergues - residencias

Augmentation of tibial plateau fractures with Trabecular Metal™: a biomechanical study

<p>Abstract</p> <p>Background</p> <p>Restoration and maintenance of the plateau surface are the key points in the treatment of tibial plateau fractures. Any deformity of the articular surface jeopardizes the future of the knee by causing osteoarthritis and axis deviation. The purpose of this study is to evaluate the effect of Trabecular Metal (porous tantalum metal) on stability and strength of fracture repair in the central depression tibial plateau fracture.</p> <p>Method</p> <p>Six matched pairs of fresh frozen human cadaveric tibias were fractured and randomly assigned to be treated with either the standard of treatment (impacted cancellous bone graft stabilized by two 4.5 mm screws under the comminuted articular surface) or the experimental method (the same screws supporting a 2 cm diameter Trabecular Metal (TM) disc placed under the comminuted articular surface). Each tibia was tested on a MTS machine simulating immediate postoperative load transmission with 500 Newton for 10,000 cycles and then loaded to failure to determine the ultimate strength of the construct.</p> <p>Results</p> <p>The trabecular metal construct showed 40% less caudad displacement of the articular surface (1, 32 ± 0.1 mm vs. 0, 80 ± 0.1 mm) in cyclic loading (p < 0.05). Its mechanical failure occurred at a mean of 3275 N compared to 2650 N for the standard of care construct (p < 0, 05).</p> <p>Conclusion</p> <p>The current study shows the biomechanical superiority of the trabecular metal construct compared to the current standard of treatment with regards to both its resistance to caudad displacement of the articular surface in cyclic loading and its strength at load to failure.</p

Scheduling Computational Workflows on Failure-Prone Platforms

International audienceWe study the scheduling of computational workflows on compute resources that experience exponentially distributed failures. When a failure occurs, roll-back and recovery is used to resume the execution from the last checkpointed state. The scheduling problem is to minimize the expected execution time by deciding in which order to execute the tasks in the workflow and whether to checkpoint or not checkpoint a task after it completes. We give a polynomial-time algorithm for fork graphs and show that the problem is NP-complete with join graphs. Our main result is a polynomial-time algorithm to compute the execution time of a workflow with specified to-be-checkpointed tasks. Using this algorithm as a basis, we propose efficient heuristics for solving the scheduling problem. We evaluate these heuristics for representative workflow configurations

3D face recognition under varying expressions using an integrated morphable model

Master'sMASTER OF ENGINEERIN

Resource Allocation Strategies for In-Network Stream Processing

In this paper we consider the operator mapping problem for in-network stream processing applications. In-network stream processing consists in applying a tree of operators in steady-state to multiple data objects that are continually updated at various locations on a network. Examples of in-network stream processing include the processing of data in a sensor network, or of continuous queries on distributed relational databases. We study the operator mapping problem in a ``constructive'' scenario, i.e., a scenario in which one builds a platform dedicated to the application buy purchasing processing servers with various costs and capabilities. The objective is to minimize the cost of the platform while ensuring that the application achieves a minimum steady-state throughput. The first contribution of this paper is the formalization of a set of relevant operator-placement problems as linear programs, and a proof that even simple versions of the problem are NP-complete. Our second contribution is the design of several polynomial time heuristics, which are evaluated via extensive simulations and compared to theoretical bounds for optimal solutions

Capacity and reliability of LVL beams manufactured from juvenile hardwood plantation logs

This paper summarises parts of the research outcomes of a university-government collaborative project aiming at determining the capacity and reliability of veneer-based structural products manufactured from early to midrotation (juvenile) hardwood plantations logs. Two species planted for solid timber end-products (Eucalyptus cloeziana and Corymbia citriodora) and one species traditionally grown for pulpwood (Eucalyptus globulus) were studied for the manufacture of the new products. Focus of this paper is on LVL beams. To cost-effectively determine the nominal design bending strengths of the new beams, a numerical model was developed. The model was found to accurately predict the strength of LVL beams with an average predicted to experimental ratio of 1.00 with a low coefficient of variation of 0.10. Using an established probabilistic database of the material properties of the veneered resources as model input, Monte-Carlo simulations were then performed. The design strength of the new LVL beams was established and found to be comparable to, and in some cases up to 2.5 times higher than, the ones of commercially available softwood products. Recommendations are also made in the paper on the appropriate capacity factors to be used for various service categories of structures. The proposed capacity factors were found to be 5% to 12% lower than the ones currently used in Australia for beams manufactured from mature softwood logs

Capacity and reliability of LVL beams manufactured from juvenile hardwood plantation logs

This paper summarises parts of the research outcomes of a university-government collaborative project aiming at determining the capacity and reliability of veneer-based structural products manufactured from early to midrotation (juvenile) hardwood plantations logs. Two species planted for solid timber end-products (Eucalyptus cloeziana and Corymbia citriodora) and one species traditionally grown for pulpwood (Eucalyptus globulus) were studied for the manufacture of the new products. Focus of this paper is on LVL beams. To cost-effectively determine the nominal design bending strengths of the new beams, a numerical model was developed. The model was found to accurately predict the strength of LVL beams with an average predicted to experimental ratio of 1.00 with a low coefficient of variation of 0.10. Using an established probabilistic database of the material properties of the veneered resources as model input, Monte-Carlo simulations were then performed. The design strength of the new LVL beams was established and found to be comparable to, and in some cases up to 2.5 times higher than, the ones of commercially available softwood products. Recommendations are also made in the paper on the appropriate capacity factors to be used for various service categories of structures. The proposed capacity factors were found to be 5% to 12% lower than the ones currently used in Australia for beams manufactured from mature softwood logs