Recursive Stochastic Effects in Valley Hybrid Inflation

Hybrid Inflation is a two-field model where inflation ends by a tachyonic instability, the duration of which is determined by stochastic effects and has important observational implications. Making use of the recursive approach to the stochastic formalism presented in Ref. [1], these effects are consistently computed. Through an analysis of back-reaction, this method is shown to converge in the valley but points toward an (expected) instability in the waterfall. It is further shown that quasi-stationarity of the auxiliary field distribution breaks down in the case of a short-lived waterfall. It is found that the typical dispersion of the waterfall field at the critical point is then diminished, thus increasing the duration of the waterfall phase and jeopardizing the possibility of a short transition. Finally, it is found that stochastic effects worsen the blue tilt of the curvature perturbations by an order one factor when compared with the usual slow-roll contribution.Comment: 26 pages, 6 figure

Limit theorems for Markov processes indexed by continuous time Galton--Watson trees

We study the evolution of a particle system whose genealogy is given by a supercritical continuous time Galton--Watson tree. The particles move independently according to a Markov process and when a branching event occurs, the offspring locations depend on the position of the mother and the number of offspring. We prove a law of large numbers for the empirical measure of individuals alive at time t. This relies on a probabilistic interpretation of its intensity by mean of an auxiliary process. The latter has the same generator as the Markov process along the branches plus additional jumps, associated with branching events of accelerated rate and biased distribution. This comes from the fact that choosing an individual uniformly at time t favors lineages with more branching events and larger offspring number. The central limit theorem is considered on a special case. Several examples are developed, including applications to splitting diffusions, cellular aging, branching L\'{e}vy processes.Comment: Published in at http://dx.doi.org/10.1214/10-AAP757 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Tapered, tubular polyester fabric

A tapered tubular polyester sleeve is described to serve as the flexible foundation for a spacesuit limb covering. The tube has a large end and a small end with a length to be determined. The ratio of taper is also determined by scale factors. All the warp yarns extend to the large end. A requisite number of warp yarns extend the full length of the sleeve. Other warp yarns extend from the large end but are terminated along the length of the sleeve. It is then woven with a filling yarn which extends in a full circle along the full length of the sleeve to thereby define the tapered sleeve. The sleeve after fabrication is then placed on a mandrel, heated in an oven, and then attached to the arm or other limb of the spacesuit

Handheld Augmented Reality: Effect of registration jitter on cursor-based pointing techniques

International audienceHandheld Augmented Reality relies on the registration of digital content on physical objects. Yet, the accuracy of this registration depends on environmental conditions. It is therefore important to study the impact of registration jitter on interaction and in particular on pointing at augmented objects where precision may be required. We present an experiment that compares the effect of registration jitter on the following two pointing techniques: (1) screen-centered crosshair pointing; and (2) relative pointing with a cursor bound to the physical object's frame of reference and controlled by indirect relative touch strokes on the screen. The experiment considered both tablet and smartphone form factors. Results indicate that relative pointing in the frame of the physical object is less error prone and is less subject to registration jitter than screencentered crosshair pointing

Size and polydispersity effect on the magnetization of densely packed magnetic nanoparticles

The magnetic properties of densely packed magnetic nanoparticles (MNP) assemblies are investigated from Monte Carlo simulations. The case of iron oxide nanoparticles is considered as a typical example of MNP. The main focus is put on particle size and size polydispersity influences on the magnetization curve. The particles are modeled as uniformly magnetized spheres isolated one from each other by a non magnetic layer representing the organic coating. A comparison with recent experimental results on $\gamma-$Fe$_2$O$_3$ powder samples differing by their size is given.Comment: To be published in the Journal of Applied Physics, to be found at http://jap.aip.org

Evolution after the COVID of the invisibility of precarities (ECOVIP): Overview of an action research project to decipher the urban factory of invisibility

Due to weak economies or ill-adapted public policies aggravated by the pandemic, official services dedicated to the unconditional reception and support of people in psychosocial distress in large urban areas are often put to the test. Here is the approach of the action research “Evolution after COVid-19 of the Invisibility of Precarities” (ECOVIP) dedicated to this phenomenon, as well as its first results concerning the precarity of unemployed “young” seniors (50-64 years old) in Lyon, France. This participative research is based on workshops that bring together professionals from both the front-line psychosocial field and other fields such as employment or work, and in which they are offered a free expression of their lived situations of reception of precarious people. The first results provided by the scientific and transparent analysis of these exchanges show both a fairly precise understanding of the institutional decision leading to increasing invisibility, and the emergence of innovative professional resources capable of curbing it.Due to weak economies or ill-adapted public policies aggravated by the pandemic, official services dedicated to the unconditional reception and support of people in psychosocial distress in large urban areas are often put to the test. Here is an overview of the approach of the action research “Evolution after COVid-19 of the Invisibility of Precarities” (ECOVIP) dedicated to this phenomenon, as along with its first steps showing preliminary results concerning the precarity of unemployed pre-old people in Lyon, France.This participative research is based on workshops that bring together professionals from both the front-line psychosocial field and other fields such as employment or work, and in which they are offered a free expression of their lived situations of reception of precarious people. The first results provided by the scientific and transparent analysis of these exchanges show both a fairly precise understanding of the institutional decision leading to increasing invisibility, and the emergence of innovative professional resources capable of curbing it.

Evolution after the COVID of the invisibility of precarities (ECOVIP): Overview of an action research project to decipher the urban factory of invisibility

Due to weak economies or ill-adapted public policies aggravated by the pandemic, official services dedicated to the unconditional reception and support of people in psychosocial distress in large urban areas are often put to the test. Here is the approach of the action research “Evolution after COVid-19 of the Invisibility of Precarities” (ECOVIP) dedicated to this phenomenon, as well as its first results concerning the precarity of unemployed “young” seniors (50-64 years old) in Lyon, France. This participative research is based on workshops that bring together professionals from both the front-line psychosocial field and other fields such as employment or work, and in which they are offered a free expression of their lived situations of reception of precarious people. The first results provided by the scientific and transparent analysis of these exchanges show both a fairly precise understanding of the institutional decision leading to increasing invisibility, and the emergence of innovative professional resources capable of curbing it.Due to weak economies or ill-adapted public policies aggravated by the pandemic, official services dedicated to the unconditional reception and support of people in psychosocial distress in large urban areas are often put to the test. Here is an overview of the approach of the action research “Evolution after COVid-19 of the Invisibility of Precarities” (ECOVIP) dedicated to this phenomenon, as along with its first steps showing preliminary results concerning the precarity of unemployed pre-old people in Lyon, France.This participative research is based on workshops that bring together professionals from both the front-line psychosocial field and other fields such as employment or work, and in which they are offered a free expression of their lived situations of reception of precarious people. The first results provided by the scientific and transparent analysis of these exchanges show both a fairly precise understanding of the institutional decision leading to increasing invisibility, and the emergence of innovative professional resources capable of curbing it.

Reply to comment by A. Revil and N. Linde on 'Streaming potential dependence on water-content in Fontainebleau sand'

International audienceRevil and Linde recently commented our paper concerning streaming potential (SP) measurements in unsaturated sand during drainage experiments. This comment suggests that the approach used to infer SP coefficients was inappropriate for unsaturated conditions, and therefore yielded wrong conclusions and 'unphysical' results regarding the behaviour of the relative SP coefficient. This reply argues that even if in Allègre et al. we neglected some secondary electrokinetic sources, the resulting conclusions are still representative of the behaviour of the true SP coefficient, and that the remarks of Revil & Linde arose from a misunderstanding of the drainage experiment conditions. We also find support for our results from a comparison between our observations and previous experimental studies