On the Sunyaev-Zel'dovich effect from dark matter annihilation or decay in galaxy clusters

We revisit the prospects for detecting the Sunyaev Zel'dovich (SZ) effect induced by dark matter (DM) annihilation or decay. We show that with standard (or even extreme) assumptions for DM properties, the optical depth associated with relativistic electrons injected from DM annihilation or decay is much smaller than that associated with thermal electrons, when averaged over the angular resolution of current and future experiments. For example, we find: $\tau_{\rm DM} \sim 10^{-9}-10^{-5}$ (depending on the assumptions) for \mchi = 1 GeV and a density profile $\rho\propto r^{-1}$ for a template cluster located at 50 Mpc and observed within an angular resolution of $10"$, compared to $\tau_{\rm th}\sim 10^{-3}-10^{-2}$. This, together with a full spectral analysis, enables us to demonstrate that, for a template cluster with generic properties, the SZ effect due to DM annihilation or decay is far below the sensitivity of the Planck satellite. This is at variance with previous claims regarding heavier annihilating DM particles. Should DM be made of lighter particles, the current constraints from 511 keV observations on the annihilation cross section or decay rate still prevent a detectable SZ effect. Finally, we show that spatial diffusion sets a core of a few kpc in the electron distribution, even for very cuspy DM profiles, such that improving the angular resolution of the instrument, e.g. with ALMA, does not necessarily improve the detection potential. We provide useful analytical formulae parameterized in terms of the DM mass, decay rate or annihilation cross section and DM halo features, that allow quick estimates of the SZ effect induced by any given candidate and any DM halo profile.Comment: 27 p, 6 figs, additional section on spatial diffusion effects. Accepted for publication in JCA

Multi-level experimental and numerical analysis of composite stiffener debonding. Part 1: Non-specific specimen level

International audienceA multi-level analysis of skin/stiffener debonding is used for the fuselage design of future aircraft during postbuckling. The specimens composed of a laminate (the skin) to which an over-thickness (the flange) had been added were subjected to four-point bending, which led to interface failure between the flange and the skin. These tests were performed with several configurations and parameters, such as the orientation of the plies located at the interface, temperature (-50°C, 20°C and 70°C), ageing and manufacturing mode: co-cured or co-bonded. The flange shape (tapered or not) and thickness were also considered. Test data are presented and analyzed and critical configurations are identified. Finite element models were developed and the flange debonding loads computed, firstly by use of cohesive models and then through a fracture mechanics approach (Virtual Crack Closure Technique). In both cases, the Benzeg-gagh-Kenane criterion was selected and proved its efficiency but the fracture mechanics approach was an order of magnitude less time consuming, which will enable future modelling to include larger sizes

Change of scale strategy for the microstructural modelling of polymeric rohacell foams

International audienceIn this paper a numerical model dedicated to the simulation of the mechanical behaviour of polymeric Rohacell foams is presented. The finite elements model is developed at the scale of the microstructure idealized by a representative unit cell: the truncated octahedron. Observations made on micrographs of Rohacell lead to mesh this representative unit cell as a lattice of beam elements. Each beam is assigned a brittle linear elastic mechanical behaviour in tension and an elasto-plastic behaviour in compression. The plasticity in compression is introduced as a way to mimic the buckling of the edges of the cells observed in experimental crushing tests. A contact law introduced between the beams stands for densification. A change in scale is then realized by increasing the length of the edges of the unit cell. Several computations show the ability of the proposed approach to preserve the physical degradation phenomena and the loads while drastically decreasing the computational time

Changes in Motor Competence after a Brief Physical Education Intervention Program in 4 and 5-Year-Old Preschool Children

Low motor competence (MC) can cause low participation in physical activities in preschool children, and together with a high caloric intake, it can lead to obesity. Interventions on motor skills are effective in the short term to improve MC, therefore the objectives of this study were (1) to investigate the effect of a short six-week program on levels of motor competence in preschool children, and (2) to examine the effects of gender-based intervention. A total of 156 preschool children (5.20 ± 0.54 years old) from Lugo (Spain) participated. A quasi-experimental pre–post-test design was used with a control group of 76 students. The Movement Assessment Battery for Children—2nd Edition (MABC-2) was used to collect the data. Significant differences between the control and experimental groups were found after the intervention program in aiming and catching (p < 0.001), balance (p < 0.001), the total score of eight tests (p < 0.001), and total percentile score (p < 0.001). The results regarding gender in the experimental group showed a reduction in differences with respect to the initial results except in aiming and catching, where scores were higher in boys. The data suggest that the application of specific intervention programs in MC could positively influence the improvement of MC in preschool children, thus reducing differences between gendersS

Filtros para un cabezal de comunicaciones entre vehículos

In this paper two reconfigurable bandpass filters able to switch between WiFi and UMTS for transmit and receive band standards are presented. The filters are designed in such a way that center frequency and bandwidth specifications are precisely met by defining two switchable filter topologies. Design specifications require two center frequency states, one at 2.440 GHz with an 80 MHz bandwidth and a second center frequency state at 1.955 GHz with a 140 MHz bandwidth for the WiFi and UMTS transmit bands. The second filter is able to have one center frequency at 2.440 GHz with an 80 MHz bandwidth and a second center frequency state at 2.165 GHz with a 110 MHz bandwidth for the WiFi and UMTS receive bands, respectively. Filter simulations were performed to match the required filters specifications. Measured results on the transmit filter show a very good agreement with the simulations where a 2.428 GHz center frequency with a 71 MHz bandwidth was obtained for the WiFi state, and a 1.939 GHz center frequency with a 144 MHz bandwidth was obtained for the UMTS filter state. Simulated results on the receive filter show a very good agreement with the specified parameters. The filters specifications were successfully matched with the proposed filter topologies.Postprint (published version

Quantitative full-colour transmitted light microscopy and dyes for concentration mapping and measurement of diffusion coefficients in microfluidic architectures

International audienceA simple and versatile methodology has been developed for the simultaneous measurement of multiple concentration profiles of colourants in transparent microfluidic systems, using a conventional transmitted light microscope, a digital colour (RGB) camera and numerical image processing combined with multicomponent analysis. Rigorous application of the Beer-Lambert law would require monochromatic probe conditions, but in spite of the broad spectral bandwidths of the three colour channels of the camera, a linear relation between the measured optical density and dye concentration is established under certain conditions. An optimised collection of dye solutions for the quantitative optical microscopic characterisation of microfluidic devices is proposed. Using the methodology for optical concentration measurement we then implement and validate a simplified and robust method for the microfluidic measurement of diffusion coefficients using an H-filter architecture. It consists of measuring the ratio of the concentrations of the two output channels of the H-filter. It enables facile determination of the diffusion coefficient, even for non-fluorescent molecules and nanoparticles, and is compatible with non-optical detection of the analyte

Analysing the performance and costs of reactive programming libraries in Java

International audienceModern services running in cloud and edge environments need to be resource-efficient to increase deployment density and reduce operating costs. Asynchronous I/O combined with asynchronous programming provides a solid technical foundation to reach these goals. Reactive programming and reactive streams are gaining traction in the Java ecosystem. However, reactive streams implementations tend to be complex to work with and maintain. This paper discusses the performance of the three major reactive streams compliant libraries used in Java applications: RxJava, Project Reactor, and SmallRye Mutiny. As we will show, advanced optimization techniques such as operator fusion do not yield better performance on realistic I/O-bound workloads, and they significantly increase development and maintenance costs

OpenMATB: A Task Battery promoting task customization, software extensibility and experiment replicability

The original Multi-Attribute Task Battery (MATB) contains a set of interactive tasks that are representative of those performed during aircraft piloting (Comstock & Arnegard, 1992). More precisely, it requires participants to simultaneously perform four tasks that are distributed over the screen: a system monitoring task, a compensatory tracking task, an auditory communication task and a resource management task. MATB task set offers a robust way to study the effects of various parameters (e.g., automation, priorities, instructions and so on) on the participant’s multitasking behavior, such as his/her decision-making, level of performance, ocular behavior, mental workload, and so on. Moreover, the nature of the reduction allows researchers to design experiments that can be used even with participants having no prior experience of aircraft. This probably explains why, since it was first published, MATB has undoubtedly become one of the most firmly established micro-world used by human factors researchers. However, as thirty years have passed since the original MATB it appears no longer adequate to meet up-to-date research requirements. Multiple incompatible re-implementations have been designed, such as MATB-II (Santiago-Espada, Myer, Latorella, & Comstock, 2011), AF-MATB (Miller, 2010), or TSU-MATB (Thanoon, Zein-Sabatto, & McCurry, 2017)

Cosmic-ray antiproton constraints on light dark matter candidates

Some direct detection experiments have recently collected excess events that could be interpreted as a dark matter (DM) signal, pointing to particles in the $\sim$10 GeV mass range. We show that scenarios in which DM can self-annihilate with significant couplings to quarks are likely excluded by the cosmic-ray (CR) antiproton data, provided the annihilation is S-wave dominated when DM decouples in the early universe. These limits apply to most of supersymmetric candidates, eg in the minimal supersymmetric standard model (MSSM) and in the next-to-MSSM (NMSSM), and more generally to any thermal DM particle with hadronizing annihilation final states.Comment: Contribution to the proceedings of TAUP-2011 (Munich, 5-9 IX 2011). 4 page

ANÁLISE DA ABORDAGEM DA CONTROLADORIA NAS DISSERTAÇÕES E TESES DOS PROGRAMAS ACADÊMICOS DE MESTRADO E DOUTORADO EM CIÊNCIAS CONTÁBEIS NO BRASIL

O objetivo do artigo é analisar a abordagem da controladoria nas dissertações e teses dos Programas acadêmicos de mestrado e doutorado em Ciências Contábeis do Brasil, defendidas no período de 2001 a 2004, em cursos recomendados pela Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), que é uma Fundação do Ministério da Educação. Trata-se de pesquisa descritiva, do tipo levantamento, com análise quantitativa e qualitativa. A população de 13 Instituições de Ensino Superior (IES) deste estudo foi identificada no sítio da CAPES entre os programas recomendados, extraindo-se uma amostra por acessibilidade de quatro instituições para compor este estudo. Os resultados da pesquisa evidenciam que entre os 201 trabalhos aprovados nas instituições da amostra, 9,45% abordaram temas de controladoria, como Balanced Scorecard, indicadores de avaliação de desempenho, planejamento estratégico e controladoria plena. Conclui-se que os trabalhos desenvolvidos com o tema específico controladoria e seus instrumentos, localizados por meio da metodologia selecionada, totalizaram um número reduzido comparativamente às linhas de pesquisa ou áreas de concentração dos Programas