The Effects of Amplification Bias in Gravitational Microlensing Experiments

Although a source star is fainter than the detection limit imposed by crowding, it is still possible to detect an event if the star is located in the seeing disk of a bright star is and gravitationally amplified: amplification bias. Using a well-constrained luminosity function, I show that $\sim 40\%$ of events detected toward the Galactic bulge are affected by amplification bias and the optical depth might be overestimated by a factor $\sim 1.7$. In addition, I show that if one takes amplification bias into consideration, the observed time scale distribution matches significantly better, especially in the short time-scale region, with the distribution expected from a mass-spectrum model in which lenses are composed of the known stellar population plus an additional population of brown dwarfs than it is without the effect of the amplification bias.Comment: 16 pages including 4 figures, ApJ, submitte

Adiabatic theorem for bipartite quantum systems in weak coupling limit

We study the adiabatic approximation of the dynamics of a bipartite quantum system with respect to one of the components, when the coupling between its two components is perturbative. We show that the density matrix of the considered component is described by adiabatic transport formulae exhibiting operator-valued geometric and dynamical phases. The present results can be used to study the quantum control of the dynamics of qubits and of open quantum systems where the two components are the system and its environment. We treat two examples, the control of an atomic qubit interacting with another one and the control of a spin in the middle of a Heisenberg spin chain

Analyses of the transmission of the disorder from a disturbed environment to a spin chain

We study spin chains submitted to disturbed kick trains described by classical dynamical processes. The spin chains are described by Heisenberg and Ising models. We consider decoherence, entanglement and relaxation processes induced by the kick irregularity in the multipartite system (the spin chain). We show that the different couplings transmit the disorder along the chain differently and also to each spin density matrix with different efficiencies. In order to analyze and to interpret the observed effects we use a semi-classical analysis across the Husimi distribution. It consists to consider the classical spin orientation movements. A possibility of conserving the order into the spin chain is finally analyzed.Comment: arXiv admin note: substantial text overlap with arXiv:1402.241

Quantum chimera states

We study a theoretical model of closed quasi-hermitian chain of spins which exhibits quantum analogues of chimera states, i.e. long life classical states for which a part of an oscillator chain presents an ordered dynamics whereas another part presents a disordered chaotic dynamics. For the quantum analogue, the chimera behavior deals with the entanglement between the spins of the chain. We discuss the entanglement properties, quantum chaos, quantum disorder and semi-classical similarity of our quantum chimera system. The quantum chimera concept is novel and induces new perspectives concerning the entanglement of multipartite systems

Nonlocal resonances in weak turbulence of gravity-capillary waves

We report a laboratory investigation of weak turbulence of water surface waves in the gravity-capillary crossover. By using time-space resolved profilometry and a bicoherence analysis, we observe that the nonlinear processes involve 3-wave resonant interactions. By studying the solutions of the resonance conditions we show that the nonlinear interaction is dominantly 1D and involves collinear wave vectors. Furthermore taking into account the spectral widening due to weak nonlinearity explains that nonlocal interactions are possible between a gravity wave and high frequency capillary ones. We observe also that nonlinear 3-wave coupling is possible among gravity waves and we raise the question of the relevance of this mechanism for oceanic waves.Comment: accepted for publication in Physical Review Letter

Dance Movement Therapy with Adolescents in a Partial Hospital Program: A Method for Engagement

Therapeutic engagement during adolescence can be a major challenge in adolescent mental health. Research has indicated therapeutic techniques designed for engaging clients are often ineffective for adolescents because adolescents bring distinctive qualities to the therapy process that differentiate them from other therapy populations. There is also limited research showing effectiveness of Dance/Movement Therapy (DMT) with the adolescent population. This capstone will present an adaptable method utilizing dance/movement therapy interventions with participants ages 12-17 in a Partial Hospital Program. The objective of this project was to examine how DMT can improve engagement in treatment with adolescents in a partial hospital program through movement experiences and emotional content. The participants were asked to engage in a series of interventions such as movement exercises, body awareness, improvisation, writing, and processing emotions. The goal of the method was to bring awareness to dance movement therapy’s value, benefits, strength and creativity. To develop a better understanding of this topic, this writer designed and adapted four dance/movement therapy sessions for the adolescents. Based on pre and post emotional responses, motivation to attend group, positive engagement and positive responses, the DMT interventions had a positive effect and can benefit adolescents and younger populations

Dance Movement Therapy with Adolescents in a Partial Hospital Program: A Method for Engagement

Therapeutic engagement during adolescence can be a major challenge in adolescent mental health. Research has indicated therapeutic techniques designed for engaging clients are often ineffective for adolescents because adolescents bring distinctive qualities to the therapy process that differentiate them from other therapy populations. There is also limited research showing effectiveness of Dance/Movement Therapy (DMT) with the adolescent population. This capstone will present an adaptable method utilizing dance/movement therapy interventions with participants ages 12-17 in a Partial Hospital Program. The objective of this project was to examine how DMT can improve engagement in treatment with adolescents in a partial hospital program through movement experiences and emotional content. The participants were asked to engage in a series of interventions such as movement exercises, body awareness, improvisation, writing, and processing emotions. The goal of the method was to bring awareness to dance movement therapy’s value, benefits, strength and creativity. To develop a better understanding of this topic, this writer designed and adapted four dance/movement therapy sessions for the adolescents. Based on pre and post emotional responses, motivation to attend group, positive engagement and positive responses, the DMT interventions had a positive effect and can benefit adolescents and younger populations

Not enough stellar mass Machos in the Galactic halo

We present an update of results from the search for microlensing towards the Large Magellanic Cloud (LMC) by EROS (Experience de Recherche d'Objets Sombres). We have now monitored 25 million stars over three years. Because of the small number of observed microlensing candidates (four), our results are best presented as upper limits on the amount of dark compact objects in the halo of our Galaxy. We discuss critically the candidates and the possible location of the lenses, halo or LMC . We compare our results to those of the MACHO group. Finally, we combine these new results with those from our search towards the Small Magellanic Cloud as well as earlier ones from the EROS1 phase of our survey. The combined data is sensitive to compact objects in the broad mass range $10^{-7} - 10$ solar masses. The derived upper limit on the abundance of stellar mass MACHOs rules out such objects as the dominant component of the Galactic halo if their mass is smaller than 2 solar masses.Comment: 7 pages, 4 figures, presented at the XIX International Conference on Neutrino Physics and Astrophysics, Sudbury, Canada, June 200

Unsupervised Classification for Tiling Arrays: ChIP-chip and Transcriptome

Tiling arrays make possible a large scale exploration of the genome thanks to probes which cover the whole genome with very high density until 2 000 000 probes. Biological questions usually addressed are either the expression difference between two conditions or the detection of transcribed regions. In this work we propose to consider simultaneously both questions as an unsupervised classification problem by modeling the joint distribution of the two conditions. In contrast to previous methods, we account for all available information on the probes as well as biological knowledge like annotation and spatial dependence between probes. Since probes are not biologically relevant units we propose a classification rule for non-connected regions covered by several probes. Applications to transcriptomic and ChIP-chip data of Arabidopsis thaliana obtained with a NimbleGen tiling array highlight the importance of a precise modeling and the region classification