Carrier depletion and grain misorientations on individual grain boundaries of polycrystalline si thin films

Structural and microelectrical properties of grain boundaries (GBs) in polycrystalline Si thin films were investigated by electron backscattering diffraction (EBSD) and scanning capacitance microscopy (SCM). The SCM measurements revealed highly nonuniform carrier depletions among the GBs, indicating the variety of electrical properties due to the specific GB structures. The EBSD measurement showed that the films are weakly [001]-oriented with small fractions of grains in the [111] and [110] orientations. Comparison of the SCM and EBSD measurements taken on the same film area led to the following observations: (1) Σ3 GBs do not exhibit carrier depletions and thus do not have charged deep levels; (2) Some Σ9 GBs exhibit carrier depletions and some do not, indicating that the intrinsic Σ9 GBs do not have charged deep levels and the carrier depletions are due to impurity gettering at the GBs; (3) No significant relationship between the carrier depletion behavior and the grain misorientationwas found so far on the GBs with random misorientations; (4) The carrier depletion behavior does not depend only on the grain misorientation but also on the facet where the GB is taken. ©2009 IEEE.published_or_final_versionThe 34th IEEE Conference on Photovoltaic Specialists (PVSC 2009), Philadelphia, PA., 7-12 June 2009. In Conference Record, 2009, p. 000471-00047

Cognitively-inspired Agent-based Service Composition for Mobile & Pervasive Computing

Automatic service composition in mobile and pervasive computing faces many challenges due to the complex and highly dynamic nature of the environment. Common approaches consider service composition as a decision problem whose solution is usually addressed from optimization perspectives which are not feasible in practice due to the intractability of the problem, limited computational resources of smart devices, service host's mobility, and time constraints to tailor composition plans. Thus, our main contribution is the development of a cognitively-inspired agent-based service composition model focused on bounded rationality rather than optimality, which allows the system to compensate for limited resources by selectively filtering out continuous streams of data. Our approach exhibits features such as distributedness, modularity, emergent global functionality, and robustness, which endow it with capabilities to perform decentralized service composition by orchestrating manifold service providers and conflicting goals from multiple users. The evaluation of our approach shows promising results when compared against state-of-the-art service composition models.Comment: This paper will appear on AIMS'19 (International Conference on Artificial Intelligence and Mobile Services) on June 2

Information fusion from multiple databases using meta-association rules

Nowadays, data volume, distribution, and volatility make it difficult to search global patterns by applying traditional Data Mining techniques. In the case of data in a distributed environment, sometimes a local analysis of each dataset separately is adequate but some other times a global decision is needed by the analysis of the entire data. Association rules discovering methods typically require a single uniform dataset and managing with the entire set of distributed data is not possible due to its size. To address the scenarios in which satisfying this requirement is not practical or even feasible, we propose a new method for fusing information, in the form of rules, extracted from multiple datasets. The proposed model produces meta-association rules, i.e. rules in which the antecedent or the consequent may contain rules as well, for finding joint correlations among trends found individually in each dataset. In this paper, we describe the formulation and the implementation of two alternative frameworks that obtain, respectively, crisp meta-rules and fuzzy meta-rules. We compare our proposal with the information obtained when the datasets are not separated, in order to see the main differences between traditional association rules and meta-association rules. We also compare crisp and fuzzy methods for meta-association rule mining, observing that the fuzzy approach offers several advantages: it is more accurate since it incorporates the strength or validity of the previous information, produces a more manageable set of rules for human inspection, and allows the incorporation of contextual information to the mining process expressed in a more human-friendly format

Probabilistic Guarded P Systems, A New Formal Modelling Framework

Multienvironment P systems constitute a general, formal framework for modelling the dynamics of population biology, which consists of two main approaches: stochastic and probabilistic. The framework has been successfully used to model biologic systems at both micro (e.g. bacteria colony) and macro (e.g. real ecosystems) levels, respectively. In this paper, we extend the general framework in order to include a new case study related to P. Oleracea species. The extension is made by a new variant within the probabilistic approach, called Probabilistic Guarded P systems (in short, PGP systems). We provide a formal definition, a simulation algorithm to capture the dynamics, and a survey of the associated software.Ministerio de Economía y Competitividad TIN2012- 37434Junta de Andalucía P08-TIC-0420

Optical response of grain boundaries in upgraded metallurgical-grade silicon for photovoltaics

Using upgraded metallurgical-grade silicon (UMG-Si) is a cost-effective and energy-efficient approach for the production of solar cells. Grain boundaries (GBs) play a major role in determining the device performance of multicrystalline Si (mc-Si) solar cells. In this study two UMG-Si wafers, one from the middle part of a brick and the other from the top part of the same brick, were investigated. An excellent correlation was found between the grain misorientation and the corresponding optical response of GBs as indicated by photoluminescence (PL) imaging, electron backscattered diffraction (EBSD), and cross-sectional transmission electron microscopy (TEM). In addition, the PL features at random GBs depend also on the impurity levels in the wafer. In particular the PL emission was greatly enhanced in the narrow regions close to the random GB in the top wafer, which is an interesting phenomenon that may have potential application in high efficiency light-emission diodes (LEDs) based on Si. © 2011 Elsevier B.V.postprin

More productive in vitro culture of Cryptosporidium parvum for better study of the intra- and extracellular phases

The great difficulties in treating people and animals suffering from cryptosporidiosis have prompted the development of in vitro experimental models. Due to the models of in vitro culture, new extracellular stages of Cryptosporidium have been demonstrated. The development of these extracellular phases depends on the technique of in vitro culture and on the species and genotype of Cryptosporidium used. Here, we undertake the molecular characterization by polymerase chain reaction-restriction fragment lenght polymorphism of different Cryptosporidium isolates from calves, concluding that all are C. parvum of cattle genotype, although differing in the nucleotide at positions 472 and 498. Using these parasites, modified the in vitro culture technique for HCT-8 cells achieving greater multiplication of parasites. The HCT-8 cell cultures, for which the culture had not been renewed in seven days, were infected with C. parvum sporozoites in RPMI-1640 medium with 10% IFBS, CaCl2 and MgCl2 1 mM at pH 7.2. Percentages of cell parasitism were increased with respect to control cultures (71% at 48 h vs 14.5%), even after two weeks (47% vs 1.9%). Also, the percentage of extracellular stages augmented (25.3% vs 1.1% at 96 h). This new model of in vitro culture of C. parvum will enable easier study of the developmental phases of C. parvum in performing new chemotherapeutic assays

Learning to breathe: developmental phase transitions in oxygen status

Plants are developmentally disposed to considerable changes in oxygen availability, yet our understanding of the importance of hypoxia is almost entirely limited to stress biology. Differential patterns of the abundance of oxygen, nitric oxide (.NO) and reactive oxygen species (ROS), and redox potential occur in organs and meristems, and examples are emerging in the literature of mechanistic relationships of these to development. Here, we describe the convergence of these cues in meristematic and reproductive tissues, and discuss the evidence for regulated hypoxic niches, within which oxygen-, ROS-, .NO- and redox-dependent signalling curate developmental transitions in plants

Identification and Characterization of Epithelial Cell-Derived Dense Bodies Produced upon Cytomegalovirus Infection

Dense bodies (DB) are complex, noninfectious particles produced during CMVinfection containing envelope and tegument proteins that may be ideal candidates as vaccines. Although DB were previously described in fibroblasts, no evidence of DB formation has been shown after propagating CMV in epithelial cells. In the present study, both fibroblast MRC-5 and epithelial ARPE-19 cells were used to study DB production during CMV infection. We demonstrate the formation of epithelial cell-derived DB, mostly located as cytoplasmic inclusions in the perinuclear area of the infected cell. DB were gradient-purified, and the nature of the viral particles was confirmed using CMV-specific immunelabeling. Epithelial cell-derived DB had higher density and more homogeneous size (200-300 nm) compared to fibroblast-derived DB (100-600 nm).In agreement with previous results characterizing DB from CMV-infected fibroblasts, the pp65 tegument protein was predominant in the epithelial cell-derived DB. Our results also suggest that epithelial cells had more CMV capsids in the cytoplasm and had spherical bodies compatible with nucleus condensation (pyknosis) in cells undergoing apoptosis that were not detected in MRC-5 infected cells at the tested time post-infection. Our results demonstrate the formation of DB in CMV-infected ARPE-19 epithelial cells that may be suitable candidate to develop a multiprotein vaccine with antigenic properties similar to that of the virions while not including the viral genome.This study was supported by the Spanish Ministry of Science, Innovation and University, Instituto de Salud Carlos III Grant/Award Numbers: PI17CIII-00014 (MPY110/18); PI20CIII-00009 (MPY303/20); DTS18CIII/00006 (MPY127/19). E.G-R is supported by the Sara Borrell Program (CD18CIII/00007), Instituto de Salud Carlos III, Ministerio de Ciencia, Innovación y Universidades. MJR is supported by the PTA Program (PTA2017-14233-I), Ministerio de Ciencia, Innovación y Universidades.S

SpikingLab: modelling agents controlled by Spiking Neural Networks in Netlogo

The scientific interest attracted by Spiking Neural Networks (SNN) has lead to the development of tools for the simulation and study of neuronal dynamics ranging from phenomenological models to the more sophisticated and biologically accurate Hodgkin-and-Huxley-based and multi-compartmental models. However, despite the multiple features offered by neural modelling tools, their integration with environments for the simulation of robots and agents can be challenging and time consuming. The implementation of artificial neural circuits to control robots generally involves the following tasks: (1) understanding the simulation tools, (2) creating the neural circuit in the neural simulator, (3) linking the simulated neural circuit with the environment of the agent and (4) programming the appropriate interface in the robot or agent to use the neural controller. The accomplishment of the above-mentioned tasks can be challenging, especially for undergraduate students or novice researchers. This paper presents an alternative tool which facilitates the simulation of simple SNN circuits using the multi-agent simulation and the programming environment Netlogo (educational software that simplifies the study and experimentation of complex systems). The engine proposed and implemented in Netlogo for the simulation of a functional model of SNN is a simplification of integrate and fire (I&F) models. The characteristics of the engine (including neuronal dynamics, STDP learning and synaptic delay) are demonstrated through the implementation of an agent representing an artificial insect controlled by a simple neural circuit. The setup of the experiment and its outcomes are described in this work

England SimSmoke: the impact of nicotine vaping on smoking prevalence and smoking‐attributable deaths in England

BACKGROUND AND AIMS: While the use of nicotine vaping products (NVPs) is widespread, their impact on smoking prevalence is controversial. This study considered the potential impact of NVPs on smoking prevalence in England. DESIGN: Indirect simulation model. The England SimSmoke model is validated through 2012, before NVP use became more widely used by smokers. Because information on NVP-related transitions is limited, an indirect method is used; the difference in observed smoking prevalence (reflecting NVPs) is compared with a 2012-2019 counterfactual No-NVP scenario (without NVPs) to estimate the impact of NVPs on smoking and smoking-attributable deaths. SETTING: England, 2000-2019. PARTICIPANTS: Nationally representative sample of population. MEASUREMENTS: England's population, mortality rates, and smoking prevalence estimates from three national surveys and tobacco control policies. FINDINGS: Between 2000 and 2012, SimSmoke projected a decline in age 18+ smoking prevalence of 23.5% in men and 27.0% in women. These projections, as well as those by specific age groups, were generally consistent with findings from the three national surveys. Comparing 2012-2019 relative reduction in age 18+ prevalence from the Annual Population Survey (males 27.5%) with the model-predicted No-NVP reduction (males 7.3%), the implied NVP-attributable relative reduction in adult smoking prevalence was 20.2% (95% CI, 18.8%-22.0%) for males and 20.4% (18.7%-22.2%) for females. The NVP-attributable reduction was 27.2% (22.8%-31.6%) for males and 31.7% (27.4%-36.5%) for females ages 18-24 and 18.6% (15.2%-21.8%) for males and 15.0% (11.1%-18.8%) for females ages 25-34, with similar reductions for ages 35 and above. The implied reduction in smoking prevalence between 2012 and 2019 equates to 165,660 (132,453-199,501) averted deaths by 2052. Other surveys yielded smaller, but relatively consistent results. CONCLUSIONS: An indirect method of simulation modeling indicates that substantial reductions in smoking prevalence occurred in England from 2012 to 2019 coinciding with the growth in nicotine vaping product use