Gap Filling of 3-D Microvascular Networks by Tensor Voting

We present a new algorithm which merges discontinuities in 3-D images of tubular structures presenting undesirable gaps. The application of the proposed method is mainly associated to large 3-D images of microvascular networks. In order to recover the real network topology, we need to fill the gaps between the closest discontinuous vessels. The algorithm presented in this paper aims at achieving this goal. This algorithm is based on the skeletonization of the segmented network followed by a tensor voting method. It permits to merge the most common kinds of discontinuities found in microvascular networks. It is robust, easy to use, and relatively fast. The microvascular network images were obtained using synchrotron tomography imaging at the European Synchrotron Radiation Facility. These images exhibit samples of intracortical networks. Representative results are illustrated

Momentum distribution of a dilute unitary Bose gas with three-body losses

Using Boltzmann's equation, we study the effect of three-body losses on the momentum distribution of a homogeneous unitary Bose gas in the dilute limit where quantum correlations are negligible. We calculate the momentum distribution of the gas and show that inelastic collisions are quantitatively as important as a second order virial correction.Comment: 4 pages + supplemental materia

Phase and antigenic variation in mycoplasmas

With their reduced genome bound by a single membrane, bacteria of the Mycoplasma species represent some of the simplest autonomous life forms. Yet, these minute prokaryotes are able to establish persistent infection in a wide range of hosts, even in the presence of a specific immune response. Clues to their success in host adaptation and survival reside, in part, in a number of gene families that are affected by frequent, stochastic genotypic hanges. These genetic events alter the expression, the size and the antigenic structure of abundant surface proteins, thereby creating highly versatile and dynamic surfaces within a clonal population. This phenomenon provides these wall-less pathogens with a means to escape the host immune response and to modulate surface accessibility by masking and unmasking stably expressed components that are essential in host interaction and survival

Enhanced Lasso Recovery on Graph

This work aims at recovering signals that are sparse on graphs. Compressed sensing offers techniques for signal recovery from a few linear measurements and graph Fourier analysis provides a signal representation on graph. In this paper, we leverage these two frameworks to introduce a new Lasso recovery algorithm on graphs. More precisely, we present a non-convex, non-smooth algorithm that outperforms the standard convex Lasso technique. We carry out numerical experiments on three benchmark graph datasets

Consumers' immediate memory for prices

In this article, the authors examine the cognitive mechanics involved in keeping prices in short-terme memory for subsequent recall. Consumers code and store prices verbally, visually, and in terms of their magnitude. The encoding used influences immediate recall performance. The memorability of prices depends on their verbal length, usualness and overall magnitude. They find that the performance of consumers recall prices better than what previous digit span studies with simple numbers have suggested.consumer behavior; numerical cognition; price memory

Eliciting Risk Preferences: A Field Experiment on a Sample of French Farmers

We designed a field experiment involving real payments to elicit farmers’ risk preferences. Farmers are a very interesting sample to study since risk has always played an important role in agricultural producers’ decisions. Besides, European farmers may face more risky situations in the future. In this context, it is very important for any economic analysis focusing on agriculture to correctly assess farmers’ behaviour in the face of different sources of risk. We test for two descriptions of farmers’ behaviour: expected utility and cumulative prospect theory. We use two elicitation methods based on the procedures of Holt and Laury (2002) and Tanaka et al. (2010) on a sample of 30 French farmers. The experiment consists in asking subjects to make series of choices between two lotteries with varying probabilities and outcomes. We estimate parameters describing farmers’ risk preferences derived from structural models. We find farmers are slightly risk averse in the expected utility framework. In the cumulative prospect theory frame, we find farmers display either loss aversion or probability weighting, tending to overweight small probabilities and to underweight high probabilities. In our study, expected utility is not a good description of farmers’ behaviour towards risk.Risk Attitudes, Field Experiment, Farming, Risk and Uncertainty, C93, D81, Q10,

Mode Competition in Dual-Mode Quantum Dots Semiconductor Microlaser

This paper describes the modeling of quantum dots lasers with the aim of assessing the conditions for stable cw dual-mode operation when the mode separation lies in the THz range. Several possible models suited for InAs quantum dots in InP barriers are analytically evaluated, in particular quantum dots electrically coupled through a direct exchange of excitation by the wetting layer or quantum dots optically coupled through the homogeneous broadening of their optical gain. A stable dual-mode regime is shown possible in all cases when quantum dots are used as active layer whereas a gain medium of quantum well or bulk type inevitably leads to bistable behavior. The choice of a quantum dots gain medium perfectly matched the production of dual-mode lasers devoted to THz generation by photomixing.Comment: First draft of a paper submitted to Phys Rev A. This version includes an extended discussion about dual-mode lasers and recall some known results about stability. Extended bibliograph