Approximation Methods for Singular Diffusions Arising in Genetics

Stochastic models in population genetics leading to diffusion equations are considered. When the drift and the square of the diffusion coefficients are polynomials, an infinite system of ordinary differential equations for the moments of the diffusion process can be derived using the Martingale property. An example is provided to show how the classical Fokker-Planck Equation approach may not be appropriate for this derivation. A Gauss-Galerkin method for approximating the laws of the diffusion, originally proposed by Dawson (1980), is examined. In the few special cases for which exact solutions are known, comparison shows that the method is accurate and the new algorithm is efficient. Numerical results relating to population genetics models are presented and discussed. An example where the Gauss-Galerkin method fails is provided

Population Genetics: Estimation of Distributions through Systems of Non-Linear Differential Equations

In stochastic population genetics, the fundamental quantity used for describing the genetic composition of a Mendelian population is the gene frequency. The process of change in the gene frequency is generally modeled as a stochastic process satisfying a stochastic differential equation. The drift and diffusion coefficients in this equation reflect such mechanisms as mutation, selection, and migration that affect the population. Except in very simple cases, it is difficult to determine the probability law of the stochastic process of change in gene frequency. We present a method for obtaining approximations of this process, enabling us to study models more realistic than those treated previously, called the Gauss Galerkin method

Apports des réseaux sociaux pour la gestion de la relation client

National audienceDepuis quelques années, le Web s'est transformé en une plateforme d'échanges. La gestion de relation client doit évoluer pour tirer partie des données disponibles sur les réseaux sociaux et mettre l'entreprise au coeur des échanges. Nous proposons dans cet article une approche générique de détection de communautés de clients d'une entreprise, basée sur leur comportement explicite et implicite, intégrant des données de sources diverses. Nous définissons une mesure de similarité, entre un utilisateur et un tag, prenant en compte la notation et la consultation des ressources et le réseau social de l'utilisateur. Nous validons cette approche sur une base exemple en utilisant deux méthodes de détection de communautés pour trois cas d'utilisation

The Patient's Guide to Psoriasis Treatment. Part 4: Goeckerman Therapy.

BackgroundThe Goeckerman regimen remains one of the oldest, most reliable treatment options for patients with moderate to severe psoriasis. Goeckerman therapy currently consists of exposure to ultraviolet B light and application of crude coal tar. The details of the procedure can be confusing and challenging to understand for the first-time patient or provider.ObjectiveTo present a freely available online guide and video on Goeckerman treatment that explains the regimen in a patient-oriented manner.MethodsThe Goeckerman protocol used at the University of California-San Francisco Psoriasis and Skin Treatment Center as well as available information from the literature were reviewed to design a comprehensive guide for patients receiving Goeckerman treatment.ResultsWe created a printable guide and video resource that covers the supplies needed for Goeckerman regimen, the treatment procedure, expected results, how to monitor for adverse events, and discharge planning.ConclusionThis new resource is beneficial for prospective patients planning to undergo Goeckerman treatment, healthcare providers, and trainees who want to learn more about this procedure. Online media and video delivers material in a way that is flexible and often familiar to patients

The Patient's Guide to Psoriasis Treatment. Part 2: PUVA Phototherapy.

BackgroundPUVA treatment is photochemotherapy for psoriasis that combines psoralen with UVA radiation. Although PUVA is a very effective treatment option for psoriasis, there is an absence of patient resources explaining and demonstrating the process of PUVA. Studies have shown that patients who viewed videos explaining the treatment procedures for various medical conditions had a greater understanding of their treatment and were more active participants in their health.ObjectiveTo present a freely available online guide and video on PUVA treatment designed for patient education on PUVA.MethodsThe PUVA treatment protocol used at the University of California-San Francisco Psoriasis and Skin Treatment Center as well as available information from the literature was reviewed to design a comprehensive guide for patients receiving PUVA treatment.ResultsWe created a printable guide and video resource that reviews the benefits and risks of PUVA, discusses the three types of PUVA (hand-foot soak, full body soak, and systemic), demonstrates the PUVA process, and provides practical tips for safe use.ConclusionOnline media and video delivers material in a way that is flexible and often familiar to patients. This new format is beneficial for prospective patients planning to undergo PUVA treatment, health-care providers, and trainees who want to learn more about this treatment

Relationships between calpains and glutamate- or kainate-induced apoptosis in Xenopus laevis tadpoles

Abstract: Cell glutamate-damage induced by overstimulation of ionotropic receptors is initiated by modification of the intracellular Ca2+ homeostasis and the concomitant activation of Ca2+-dependent cysteine proteases, the calpain and caspase families. The resultant cleavage of target molecules mediates a critical function in the execution of the cell death. In this work, we investigated relationships between the activity of calpain and glutamate-orkainate-induced apoptosis in several organs of Xenopus laevis tadpole. Animals (stage 48) were incubated for 3 hours with glutamate (30–120 mM) or kainate (0.015–0.75 mM) and the rise of both apoptosis and calpain was observed in several organs. Our results indicated that glutamate (120 mM) or kainate (0.15 mM) exposure induced cell death with apoptotic features. The toxic effects of drugs into the organs were variable. Apoptosis was probably not the only form of cell death and option of necrosis or apoptosis was depending on the stimulation degree of the receptor, i.e. the receptor type, intensity and time course of molecule exposure. The increase of ubiquitous calpain was not correlated with the peak of apoptosis, suggesting the role of calpain in cell death was complex: calpain and caspase pathways were tightly interrelated in the glutamate- or kainate-induced cell death and the contribution of calpain to another type of death than apoptosis was perhaps preferred

Orthology guided transcriptome assembly of Italian ryegrass and meadow fescue for single-nucleotide polymorphism discovery

Single-nucleotide polymorphisms (SNPs) represent natural DNA sequence variation. They can be used for various applications including the construction of high-density genetic maps, analysis of genetic variability, genome-wide association studies, and mapbased cloning. Here we report on transcriptome sequencing in the two forage grasses, meadow fescue (Festuca pratensis Huds.) and Italian ryegrass (Lolium multiflorum Lam.), and identification of various classes of SNPs. Using the Orthology Guided Assembly (OGA) strategy, we assembled and annotated a total of 18,952 and 19,036 transcripts for Italian ryegrass and meadow fescue, respectively. In addition, we used transcriptome sequence data of perennial ryegrass (L. perenne L.) from a previous study to identify 16,613 transcripts shared across all three species. Large numbers of intraspecific SNPs were identified in all three species: 248,000 in meadow fescue, 715,000 in Italian ryegrass, and 529,000 in perennial ryegrass. Moreover, we identified almost 25,000 interspecific SNPs located in 5343 genes that can distinguish meadow fescue from Italian ryegrass and 15,000 SNPs located in 3976 genes that discriminate meadow fescue from both Lolium species. All identified SNPs were positioned in silico on the seven linkage groups (LGs) of L. perenne using the GenomeZipper approach. With the identification and positioning of interspecific SNPs, our study provides a valuable resource for the grass research and breeding community and will enable detailed characterization of genomic composition and gene expression analysis in prospective Festuca Lolium hybrids

Tracking Plasma Lactate Concentration in Vivo with a Catheter-Tip L-Lactate Sensor

To circumvent the problems of repeated blood sampling for in vitro analysis, a catheter-tip L-lactate sensor has been developed. The sensor was tested in anesthetized pigs (n=6). The sensor in vivo tracked the lactate concentration non-linearly, seeming to obey Michaelis-Menten kinetics. Calibration time was short, typically 1.5 min per lactate standard. Furthermore, time drift was small, typically -1.3% to -3.3% per hour of in vivo use

Adaptive gameplay for mobile gaming

In this article we propose a game design approach to build context adaptive games. This approach is based on a model of the game structure and a generic adaptation model. Our method consists of designing different game scenarios involving different gameplay for the game then, game engine selects and proposes the appropriate one according to the context. We have conducted a pilot experiment in order to evaluate the effect of this adaptation on game and player satisfaction. We stated as hypotheses that context adaptation does not have effects on the game and player satisfaction. We have developed two versions of a mobile game and a virtual city to test these hypotheses. The results show that context adaptation increase the number of game objectives which are succeeded and decreases the number which are failed. However, player satisfaction is not always superior for the version that includes context adaptation