Reliability of a k-out-of-n: G System Subjected to Marshall-Olkin Type Shocks Concerning Magnitude

In this paper the reliability of a k-out-of-n: G system under the effect of shocks having the Marshall-Olkin type shock models, is studied. The magnitudes of the shocks are considered. The system contains n components and only functions when at least k of these components function. The system is subjected to (n + 1) shocks coming from (n + 1) different sources. The shock coming from the it h source may destroy the it h component, i = 1, . . . , n, while the shock coming from the (n + 1)t h source may destroy all components simultaneously. A shock is fatal, destroys a component (components), whenever its magnitude exceeds an upper threshold. The system reliability is obtained by considering the arrival time and the magnitude of a shock as a bivariate random variable. It is assumed that the bivariate random variables representing the arrival times and the magnitudes of the shocks are independent with non-identical bivariate distributions. Since the computation of the reliability formula obtained is not easy to handle, an algorithm is introduced for calculating the reliability formula. The reliability of a k-out-of-n: G system subjected to independent and identical shocks is obtained as a special case, as well as the reliabilities of the series and the parallel systems. As an application, the bivariate exponential Gumbel distribution is considered. Also, numerical illustrations are performed to highlight the results obtained

A Prospective Cohort Study on IRS Gene Polymorphisms in Type 2 Diabetes Mellitus Patients during Severe/Acute Hyperglycemia Phase 1: Association with Insulin Resistance

Purpose: To investigate the genetic polymorphisms that may contribute to the worsening of insulin resistance in type 2 diabetes mellitus (T2DM) with severe or acute hyperglycemia.Methods: This is a prospective cohort study involving 156 T2DM patients with severe or acute hyperglycemia from all medical wards of the National University of Malaysia Medical Centre (UKMMC) that were placed on insulin therapy. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to determine the genetic association of insulin receptor substrate (IRS) gene with insulin resistance. Insulin resistance status was determined using the homeostatic model assessment for insulin resistance (HOMA-IR) index.Results: IRS1 polymorphisms were associated with increased insulin resistance (X2 = 5.09, p = 0.023) in T2DM patients with severe/acute hyperglycemia. IRS2 polymorphisms were not associated with insulin resistance (X2 = 0.69, p = 0.406) in this group of patients.Conclusion: IRS1 genetic factor alone may be a significant genetic determinant for insulin resistance in T2DM patients during severe/acute phase hyperglycemia.Keywords: Insulin receptor substrate, Genetic, Polymorphism, Diabetes, Insulin resistance, Hyperglycemia, IRS1, IRS

Dimension dependent hypercontractivity for Gaussian kernels

We derive sharp, local and dimension dependent hypercontractive bounds on the Markov kernel of a large class of diffusion semigroups. Unlike the dimension free ones, they capture refined properties of Markov kernels, such as trace estimates. They imply classical bounds on the Ornstein-Uhlenbeck semigroup and a dimensional and refined (transportation) Talagrand inequality when applied to the Hamilton-Jacobi equation. Hypercontractive bounds on the Ornstein-Uhlenbeck semigroup driven by a non-diffusive L\'evy semigroup are also investigated. Curvature-dimension criteria are the main tool in the analysis.Comment: 24 page

On the dynamical behavior of the ABC model

We consider the ABC dynamics, with equal density of the three species, on the discrete ring with $N$ sites. In this case, the process is reversible with respect to a Gibbs measure with a mean field interaction that undergoes a second order phase transition. We analyze the relaxation time of the dynamics and show that at high temperature it grows at most as $N^2$ while it grows at least as $N^3$ at low temperature

Intermediate-Distance String Effects in Wilson Loops via Boundary Action

The density profile of the QCD flux tube is investigated within the framework of the L¨ uscher-Weisz (LW) string action with two boundary terms. The transverse action profile and potential between static quarks are considered using Wilson’s loop overlap formalism at zero temperature in SU(2) Yang-Mills theory. We find the predictions of the LWstring matching the lattice data for the width of the energy-density and Q ¯Q potential up to a small color-source separation of R = 0.32 fm

Foundation characteristics of edible Musa triploids revealed from allelic distribution of SSR markers

Background and Aims The production of triploid banana and plantain (Musa spp.) cultivars with improved characteristics (e.g. greater disease resistance or higher yield), while still preserving the main features of current popular cultivars (e.g. taste and cooking quality), remains a major challenge for Musa breeders. In this regard, breeders require a sound knowledge of the lineage of the current sterile triploid cultivars, to select diploid parents that are able to transmit desirable traits, together with a breeding strategy ensuring final triploidization and sterility. Highly polymorphic single sequence repeats (SSRs) are valuable markers for investigating phylogenetic relationships. Methods Here, the allelic distribution of each of 22 SSR loci across 561 Musa accessions is analysed. Key Results and ConclusionsWe determine the closest diploid progenitors of the triploid 'Cavendish' and 'Gros Michel' subgroups, valuable information for breeding programmes. Nevertheless, in establishing the likely monoclonal origin of the main edible triploid banana subgroups (i.e. 'Cavendish', 'Plantain' and 'Mutika- Lujugira'), we postulated that the huge phenotypic diversity observed within these subgroups did not result from gamete recombination, but rather from epigenetic regulations. This emphasizes the need to investigate the regulatory mechanisms of genome expression on a unique model in the plant kingdom. We also propose experimental standards to compare additional and independent genotyping data for reference. (Résumé d'auteur