A general framework for consistent estimation of charge transport properties via random walks in random environments

A general framework is proposed for the study of the charge transport properties of materials via random walks in random environments (RWRE). The material of interest is modeled by a random environment, and the charge carrier is modeled by a random walker. The framework combines a model for the fast generation of random environments that realistically mimic materials morphology with an algorithm for efficient estimation of key properties of the resulting random walk. The model of the environment makes use of tools from spatial statistics and the theory of random geometric graphs. More precisely, the disordered medium is represented by a random spatial graph with directed edge weights, where the edge weights represent the transition rates of a Markov jump process (MJP) modeling the motion of the random walker. This MJP is a multiscale stochastic process. In the long term, it explores all vertices of the random graph model. In the short term, however, it becomes trapped in small subsets of the state space and makes many transitions in these small regions. This behavior makes efficient estimation of velocity by Monte Carlo simulations a challenging task. Therefore, we use aggregate Monte Carlo (AMC), introduced in [T. Brereton et al., Methodol. Comput. Appl. Probab., 16 (2014), pp. 465-484], for estimating the velocity of a random walker as it passes through a realization of the random environment. In this paper, we prove the strong consistency of the AMC velocity estimator and use this result to conduct a detailed case study, in which we describe the motion of holes in an amorphous mesophase of an organic semiconductor, dicyanovinyl-substituted oligothiophene (DCV4T). In particular, we analyze the effect of system size (i.e., number of molecules) on the velocity of single charge carriers

A task execution scheme for dew computing with state-of-the-art smartphones

The computing resources of today’s smartphones are underutilized most of the time. Using these resources could be highly beneficial in edge computing and fog computing contexts, for example, to support urban services for citizens. However, new challenges, especially regarding job scheduling, arise. Smartphones may form ad hoc networks, but individual devices highly differ in computational capabilities and (tolerable) energy usage. We take into account these particularities to validate a task execution scheme that relies on the computing power that clusters of mobile devices could provide. In this paper, we expand the study of several practical heuristics for job scheduling including execution scenarios with state-of-the-art smartphones. With the results of new simulated scenarios, we confirm previous findings and better comprehend the baseline approaches already proposed for the problem. This study also sheds some light on the capabilities of small-sized clusters comprising mid-range and low-end smartphones when the objective is to achieve real-time stream processing using Tensorflow object recognition models as edge jobs. Ultimately, we strive for industry applications to improve task scheduling for dew computing contexts. Heuristics such as ours plus supporting dew middleware could improve citizen participation by allowing a much wider use of dew computing resources, especially in urban contexts in order to help build smart cities.publishedVersio

A Simulation-based Performance Evaluation of Heuristics for Dew Computing

The evolution of smartphones allows the continuous exploitation of computing resources. This increasingly applies also to distributed environments as exemplified through utilization of network router loads in edge computing and fog computing. Combining cloud computing and mobile smart devices in dew computing contexts enables new techniques for resource utilization, data collection and data processing. However, new challenges regarding job scheduling arise. Smartphones may be used in ad-hoc networks in this context, but their heterogeneity and energy usage must be considered. We propose novel heuristics for performance measuring of distributed computing systems integrated with mobile devices and compare them with previous heuristics in a simulation environment. Our results show an overall improvement in job completion and load balancing metrics compared to previous approaches. They highlight the usefulness of pursuing this research stream for aiming at industrial implementation and evaluation

Aplicabilidade da teoria das essential facilities à propriedade industrial no sistema antitruste brasileiro

Orientador: Márcia Carla Pereira RibeiroMonografia (graduação) - Universidade Federal do Paraná,Setor de Ciências Jurídicas, Curso de Graduação em DireitoO presente trabalho apresenta a interação existente entre a propriedade industrial e as normas antitruste e busca demonstrar como a inovação adquire um papel central no processo competitivo. Além disso, analisa a propriedade industrial sob um aspecto funcional, destacando como seus objetivos fundamentais o incentivo económico à inovação e a disseminação de tecnologia, a partir de conceitos derivados da análise económica do direito e da economia da informação. Posteriormente, trata da teoria das essential facilities e descreve seus pressupostos de aplicação, bem como trata da sua compatibilidade com o ordenamento jurídico brasileiro. Por fim, versa das características das condutas anticoncorrenciais envolvendo o uso de propriedade industrial e as situações em que se apresenta como uma um bem essencial ao desenvolvimento de uma atividade económica, ponderando-se sobre as possibilidades de aplicação da teoria das essential facilities a estes casos

Hemopexin Therapy Improves Cardiovascular Function by Preventing Heme-Induced Endothelial Toxicity in Mouse Models of Hemolytic Diseases

Background-Hemolytic diseases are characterized by enhanced intravascular hemolysis resulting in heme-catalyzed reactive oxygen species generation, which leads to endothelial dysfunction and oxidative damage. Hemopexin (Hx) is a plasma heme scavenger able to prevent endothelial damage and tissue congestion in a model of heme overload. Here, we tested whether Hx could be used as a therapeutic tool to counteract heme toxic effects on the cardiovascular system in hemolytic diseases. Methods and Results\u2014By using a model of heme overload in Hx-null mice, we demonstrated that heme excess in plasma, if not bound to Hx, promoted the production of reactive oxygen species and the induction of adhesion molecules and caused the reduction of nitric oxide availability. Then, we used \u3b2-thalassemia and sickle cell disease mice as models of hemolytic diseases to evaluate the efficacy of an Hx-based therapy in the treatment of vascular dysfunction related to heme overload. Our data demonstrated that Hx prevented heme-iron loading in the cardiovascular system, thus limiting the production of reactive oxygen species, the induction of adhesion molecules, and the oxidative inactivation of nitric oxide synthase/nitric oxide, and promoted heme recovery and detoxification by the liver mainly through the induction of heme oxygenase activity. Moreover, we showed that in sickle cell disease mice, endothelial activation and oxidation were associated with increased blood pressure and altered cardiac function, and the administration of exogenous Hx was found to almost completely normalize these parameters. Conclusions-Hemopexin treatment is a promising novel therapy to protect against heme-induced cardiovascular dysfunction in hemolytic disorders

Is there sufficient Ensifer and Rhizobium species diversity in UK farmland soils to support red clover (Trifolium pratense), white clover (T. repens), lucerne (Medicago sativa) and black medic (M. lupulina)?

Rhizobia play important roles in agriculture owing to their ability to fix nitrogen through a symbiosis with legumes. The specificity of rhizobia-legume associations means that underused legume species may depend on seed inoculation with their rhizobial partners. For black medic (Medicago lupulina) and lucerne (Medicago sativa) little is known about the natural prevalence of their rhizobial partner Ensifer meliloti in UK soils, so that the need for inoculating them is unclear. We analysed the site-dependence of rhizobial seed inoculation effects on the subsequent ability of rhizobial communities to form symbioses with four legume species (Medicago lupulina, M. sativa, Trifolium repens and T. pratense). At ten organic farms across the UK, a species-diverse legume based mixture (LBM) which included these four species was grown. The LBM seed was inoculated with a mix of commercial inocula specific for clover and lucerne. At each site, soil from the LBM treatment was compared to the soil sampled prior to the sowing of the LBM (the control). From each site and each of the two treatments, a suspension of soils was applied to seedlings of the four legume species and grown in axenic conditions for six weeks. Root nodules were counted and their rhizobia isolated. PCR and sequencing of a fragment of the gyrB gene from rhizobial isolates allowed identification of strains. The number of nodules on each of the four legume species was significantly increased when inoculated with soil from the LBM treatment compared to the control. Both the proportion of plants forming nodules and the number of nodules formed varied significantly by site, with sites significantly affecting the Medicago species but not the Trifolium species. These differences in nodulation were broadly reflected in plant biomass where site and treatment interacted; at some sites there was a significant advantage from inoculation with the commercial inoculum but not at others. In particular, this study has demonstrated the commercial merit of inoculation of lucerne with compatible rhizobia