311 research outputs found

    Fluctuation Theorems for Entropy Production and Heat Dissipation in Periodically Driven Markov Chains

    Get PDF
    Asymptotic fluctuation theorems are statements of a Gallavotti-Cohen symmetry in the rate function of either the time-averaged entropy production or heat dissipation of a process. Such theorems have been proved for various general classes of continuous-time deterministic and stochastic processes, but always under the assumption that the forces driving the system are time independent, and often relying on the existence of a limiting ergodic distribution. In this paper we extend the asymptotic fluctuation theorem for the first time to inhomogeneous continuous-time processes without a stationary distribution, considering specifically a finite state Markov chain driven by periodic transition rates. We find that for both entropy production and heat dissipation, the usual Gallavotti-Cohen symmetry of the rate function is generalized to an analogous relation between the rate functions of the original process and its corresponding backward process, in which the trajectory and the driving protocol have been time-reversed. The effect is that spontaneous positive fluctuations in the long time average of each quantity in the forward process are exponentially more likely than spontaneous negative fluctuations in the backward process, and vice-versa, revealing that the distributions of fluctuations in universes in which time moves forward and backward are related. As an additional result, the asymptotic time-averaged entropy production is obtained as the integral of a periodic entropy production rate that generalizes the constant rate pertaining to homogeneous dynamics

    Multilocus microsatellite analysis of European and African Candida glabrata isolates

    Get PDF
    This study aimed to elucidate the genetic relatedness and epidemiology of 127 clinical and environmental Candida glabrata isolates from Europe and Africa using multilocus microsatellite analysis. Each isolate was first identified using phenotypic and molecular methods and subsequently, six unlinked microsatellite loci were analyzed using automated fluorescent genotyping. Genetic relationships were estimated using the minimum-spanning tree (MStree) method. Microsatellite analyses revealed the existence of 47 different genotypes. The fungal population showed an irregular distribution owing to the over-representation of genetically different infectious haplotypes. The most common genotype was MG-9, which was frequently found in both European and African isolates. In conclusion, the data reported here emphasize the role of specific C. glabrata genotypes in human infections for at least some decades and highlight the widespread distribution of some isolates, which seem to be more able to cause disease than others.This research was supported in part by the EU Mare Nostrum (EUMN-III Call) program of the European Union, grant agreement number 2011-4050/001-EMA2. Dr Sanae Rharmitt was the recipient of a scholarship (10 months) signed within the EUMN program for PhD students (F.S. 1.04.11.01 UORI) under the supervision of Prof Orazio Romeo.info:eu-repo/semantics/publishedVersio

    The restorative role of annexin A1 at the blood–brain barrier

    Get PDF
    Annexin A1 is a potent anti-inflammatory molecule that has been extensively studied in the peripheral immune system, but has not as yet been exploited as a therapeutic target/agent. In the last decade, we have undertaken the study of this molecule in the central nervous system (CNS), focusing particularly on the primary interface between the peripheral body and CNS: the blood–brain barrier. In this review, we provide an overview of the role of this molecule in the brain, with a particular emphasis on its functions in the endothelium of the blood–brain barrier, and the protective actions the molecule may exert in neuroinflammatory, neurovascular and metabolic disease. We focus on the possible new therapeutic avenues opened up by an increased understanding of the role of annexin A1 in the CNS vasculature, and its potential for repairing blood–brain barrier damage in disease and aging

    Wetlands for wastewater treatment and subsequent recycling of treated effluent : a review

    Get PDF
    Due to water scarcity challenges around the world, it is essential to think about non-conventional water resources to address the increased demand in clean freshwater. Environmental and public health problems may result from insufficient provision of sanitation and wastewater disposal facilities. Because of this, wastewater treatment and recycling methods will be vital to provide sufficient freshwater in the coming decades, since water resources are limited and more than 70% of water are consumed for irrigation purposes. Therefore, the application of treated wastewater for agricultural irrigation has much potential, especially when incorporating the reuse of nutrients like nitrogen and phosphorous, which are essential for plant production. Among the current treatment technologies applied in urban wastewater reuse for irrigation, wetlands were concluded to be the one of the most suitable ones in terms of pollutant removal and have advantages due to both low maintenance costs and required energy. Wetland behavior and efficiency concerning wastewater treatment is mainly linked to macrophyte composition, substrate, hydrology, surface loading rate, influent feeding mode, microorganism availability, and temperature. Constructed wetlands are very effective in removing organics and suspended solids, whereas the removal of nitrogen is relatively low, but could be improved by using a combination of various types of constructed wetlands meeting the irrigation reuse standards. The removal of phosphorus is usually low, unless special media with high sorption capacity are used. Pathogen removal from wetland effluent to meet irrigation reuse standards is a challenge unless supplementary lagoons or hybrid wetland systems are used
    • …
    corecore