A current-voltage model for double Schottky barrier devices

Schottky barriers are often formed at the semiconductor/metal contacts and affect the electrical behaviour of semiconductor devices. In particular, Schottky barriers have been playing a major role in the investigation of the electrical properties of mono and two-dimensional nanostructured materials, although their impact on the current-voltage characteristics has been frequently neglected or misunderstood. In this work, we propose a single equation to describe the current-voltage characteristics of two-terminal semiconductor devices with Schottky contacts. We apply the equation to numerically simulate the electrical behaviour for both ideal and non-ideal Schottky barriers. The proposed model can be used to directly estimate the Schottky barrier height and the ideality factor. We apply it to perfectly reproduce the experimental current-voltage characteristics of ultrathin molybdenum disulphide or tungsten diselenide nanosheets and tungsten disulphide nanotubes. The model constitutes a useful tool for the analysis and the extraction of relevant transport parameters in any two-terminal device with Schottky contacts

Poesías

XII, 367 p

MitoRes: a resource of nuclear-encoded mitochondrial genes and their products in Metazoa

BACKGROUND: Mitochondria are sub-cellular organelles that have a central role in energy production and in other metabolic pathways of all eukaryotic respiring cells. In the last few years, with more and more genomes being sequenced, a huge amount of data has been generated providing an unprecedented opportunity to use the comparative analysis approach in studies of evolution and functional genomics with the aim of shedding light on molecular mechanisms regulating mitochondrial biogenesis and metabolism. In this context, the problem of the optimal extraction of representative datasets of genomic and proteomic data assumes a crucial importance. Specialised resources for nuclear-encoded mitochondria-related proteins already exist; however, no mitochondrial database is currently available with the same features of MitoRes, which is an update of the MitoNuc database extensively modified in its structure, data sources and graphical interface. It contains data on nuclear-encoded mitochondria-related products for any metazoan species for which this type of data is available and also provides comprehensive sequence datasets (gene, transcript and protein) as well as useful tools for their extraction and export. DESCRIPTION: MitoRes consolidates information from publicly external sources and automatically annotates them into a relational database. Additionally, it also clusters proteins on the basis of their sequence similarity and interconnects them with genomic data. The search engine and sequence management tools allow the query/retrieval of the database content and the extraction and export of sequences (gene, transcript, protein) and related sub-sequences (intron, exon, UTR, CDS, signal peptide and gene flanking regions) ready to be used for in silico analysis. CONCLUSION: The tool we describe here has been developed to support lab scientists and bioinformaticians alike in the characterization of molecular features and evolution of mitochondrial targeting sequences. The way it provides for the retrieval and extraction of sequences allows the user to overcome the obstacles encountered in the integrative use of different bioinformatic resources and the completeness of the sequence collection allows intra- and interspecies comparison at different biological levels (gene, transcript and protein)

Computational annotation of UTR cis-regulatory modules through Frequent Pattern Mining

<p>Abstract</p> <p>Background</p> <p>Many studies report about detection and functional characterization of cis-regulatory motifs in untranslated regions (UTRs) of mRNAs but little is known about the nature and functional role of their distribution. To address this issue we have developed a computational approach based on the use of data mining techniques. The idea is that of mining frequent combinations of translation regulatory motifs, since their significant co-occurrences could reveal functional relationships important for the post-transcriptional control of gene expression. The experimentation has been focused on targeted mitochondrial transcripts to elucidate the role of translational control in mitochondrial biogenesis and function.</p> <p>Results</p> <p>The analysis is based on a two-stepped procedure using a sequential pattern mining algorithm. The first step searches for frequent patterns (FPs) of motifs without taking into account their spatial displacement. In the second step, frequent sequential patterns (FSPs) of spaced motifs are generated by taking into account the conservation of spacers between each ordered pair of co-occurring motifs. The algorithm makes no assumption on the relation among motifs and on the number of motifs involved in a pattern. Different FSPs can be found depending on different combinations of two parameters, i.e. the threshold of the minimum percentage of sequences supporting the pattern, and the granularity of spacer discretization. Results can be retrieved at the UTRminer web site: <url>http://utrminer.ba.itb.cnr.it/</url>. The discovered FPs of motifs amount to 216 in the overall dataset and to 140 in the human subset. For each FP, the system provides information on the discovered FSPs, if any. A variety of search options help users in browsing the web resource. The list of sequence IDs supporting each pattern can be used for the retrieval of information from the UTRminer database.</p> <p>Conclusion</p> <p>Computational prediction of structural properties of regulatory sequences is not trivial. The presented data mining approach is able to overcome some limits observed in other competitive tools. Preliminary results on UTR sequences from nuclear transcripts targeting mitochondria are promising and lead us to be confident on the effectiveness of the approach for future developments.</p

Biomimetic phantom with anatomical accuracy for evaluating brain volumetric measurements with magnetic resonance imaging

Purpose: Brain image volumetric measurements (BVM) methods have been used to quantify brain tissue volumes using magnetic resonance imaging (MRI) when investigating abnormalities. Although BVM methods are widely used, they need to be evaluated to quantify their reliability. Currently, the gold-standard reference to evaluate a BVM is usually manual labeling measurement. Manual volume labeling is a time-consuming and expensive task, but the confidence level ascribed to this method is not absolute. We describe and evaluate a biomimetic brain phantom as an alternative for the manual validation of BVM. Methods: We printed a three-dimensional (3D) brain mold using an MRI of a three-year-old boy diagnosed with Sturge-Weber syndrome. Then we prepared three different mixtures of styrene-ethylene/butylene-styrene gel and paraffin to mimic white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF). The mold was filled by these three mixtures with known volumes. We scanned the brain phantom using two MRI scanners, 1.5 and 3.0 Tesla. Our suggestion is a new challenging model to evaluate the BVM which includes the measured volumes of the phantom compartments and its MRI. We investigated the performance of an automatic BVM, i.e., the expectation–maximization (EM) method, to estimate its accuracy in BVM. Results: The automatic BVM results using the EM method showed a relative error (regarding the phantom volume) of 0.08, 0.03, and 0.13 (±0.03 uncertainty) percentages of the GM, CSF, and WM volume, respectively, which was in good agreement with the results reported using manual segmentation. Conclusions: The phantom can be a potential quantifier for a wide range of segmentation methods

Patient safety in organizational culture as perceived by leaderships of hospital institutions with different types of administration

OBJECTIVE To identify the perceptions of leaderships toward patient safety culture dimensions in the routine of hospitals with different administrative profiles: government, social and private organizations, and make correlations among participating institutions regarding dimensions of patient safety culture used. METHOD A quantitative cross-sectional study that used the Self Assessment Questionnaire 30 translated into Portuguese. The data were processed by analysis of variance (ANOVA) in addition to descriptive statistics, with statistical significance set at p-value ≤ 0.05. RESULTS According to the participants' perceptions, the significant dimensions of patient safety culture were 'patient safety climate' and 'organizational learning', with 81% explanatory power. Mean scores showed that among private organizations, higher values were attributed to statements; however, the correlation between dimensions was stronger among government hospitals. CONCLUSION Different hospital organizations present distinct values for each dimension of patient safety culture and their investigation enables professionals to identify which dimensions need to be introduced or improved to increase patient safety.OBJETIVO Identificar percepciones de los liderazgos acerca de las dimensiones de la cultura de seguridad del paciente en el cotidiano de hospitales de distintos perfiles administrativos: públicos, organizaciones sociales y privados, y realizar la correlación entre las instituciones participantes, de acuerdo con las dimensiones de la cultura de seguridad del paciente utilizadas. MÉTODO Estudio transversal de aspecto cuantitativo obtenido por medio de la aplicación del instrumento Self Assessment Questionnaire 30, traducido a la lengua portuguesa. Los datos fueron tratados con análisis de varianza (ANOVA), además de las estadísticas descriptivas, considerando como de significación estadística valores de p-valor ≤ 0,05. RESULTADOS Según la percepción de los participantes del estudio, las dimensiones significativas para la cultura de seguridad del paciente fueron Ambiente de Seguridad del Paciente y Aprendizaje Organizativo, con poder explicativo del 81%. El promedio de respuestas obtenidas evidenció que en las organizaciones privadas hubo mayores valores atribuidos a las cuestiones, sin embargo la correlación entre las dimensiones fue más fuerte en las organizaciones públicas. CONCLUSIÓN Las dimensiones de la cultura de seguridad del paciente tienen valores distintos en las diferentes organizaciones hospitalarias y su investigación posibilita identificar cuáles necesitan introducirse o perfeccionarse para una mayor seguridad del paciente.OBJETIVO Identificar percepções das lideranças sobre as dimensões da cultura de segurança do paciente no cotidiano de hospitais de diferentes perfis administrativos: públicos, organizações sociais e privados, e realizar correlação entre as instituições participantes, de acordo com as dimensões da cultura de segurança do paciente utilizadas. MÉTODO Estudo transversal de aspecto quantitativo obtido por meio da aplicação do instrumento Self Assessment Questionnaire 30, traduzido para a língua portuguesa. Os dados foram tratados com análise de variância (ANOVA), além das estatísticas descritivas, considerando como de significância estatística valores de p-valor ≤ 0,05. RESULTADOS Segundo a percepção dos participantes do estudo, as dimensões significativas para a cultura de segurança do paciente foram Ambiente de Segurança do Paciente e Aprendizado Organizacional, com poder explicativo de 81%. A média de respostas obtidas evidenciou que nas organizações privadas houve maiores valores atribuídos às questões, porém a correlação entre as dimensões foi mais forte nas organizações públicas. CONCLUSÃO As dimensões da cultura de segurança do paciente têm valores distintos nas diferentes organizações hospitalares e a sua investigação possibilita identificar quais necessitam ser introduzidas ou aprimoradas para maior segurança do paciente

Patient safety in organizational culture as perceived by leaderships of hospital institutions with different types of administration

OBJECTIVE To identify the perceptions of leaderships toward patient safety culture dimensions in the routine of hospitals with different administrative profiles: government, social and private organizations, and make correlations among participating institutions regarding dimensions of patient safety culture used. METHOD A quantitative cross-sectional study that used the Self Assessment Questionnaire 30 translated into Portuguese. The data were processed by analysis of variance (ANOVA) in addition to descriptive statistics, with statistical significance set at p-value ≤ 0.05. RESULTS According to the participants' perceptions, the significant dimensions of patient safety culture were 'patient safety climate' and 'organizational learning', with 81% explanatory power. Mean scores showed that among private organizations, higher values were attributed to statements; however, the correlation between dimensions was stronger among government hospitals. CONCLUSION Different hospital organizations present distinct values for each dimension of patient safety culture and their investigation enables professionals to identify which dimensions need to be introduced or improved to increase patient safety.OBJETIVO Identificar percepciones de los liderazgos acerca de las dimensiones de la cultura de seguridad del paciente en el cotidiano de hospitales de distintos perfiles administrativos: públicos, organizaciones sociales y privados, y realizar la correlación entre las instituciones participantes, de acuerdo con las dimensiones de la cultura de seguridad del paciente utilizadas. MÉTODO Estudio transversal de aspecto cuantitativo obtenido por medio de la aplicación del instrumento Self Assessment Questionnaire 30, traducido a la lengua portuguesa. Los datos fueron tratados con análisis de varianza (ANOVA), además de las estadísticas descriptivas, considerando como de significación estadística valores de p-valor ≤ 0,05. RESULTADOS Según la percepción de los participantes del estudio, las dimensiones significativas para la cultura de seguridad del paciente fueron Ambiente de Seguridad del Paciente y Aprendizaje Organizativo, con poder explicativo del 81%. El promedio de respuestas obtenidas evidenció que en las organizaciones privadas hubo mayores valores atribuidos a las cuestiones, sin embargo la correlación entre las dimensiones fue más fuerte en las organizaciones públicas. CONCLUSIÓN Las dimensiones de la cultura de seguridad del paciente tienen valores distintos en las diferentes organizaciones hospitalarias y su investigación posibilita identificar cuáles necesitan introducirse o perfeccionarse para una mayor seguridad del paciente.OBJETIVO Identificar percepções das lideranças sobre as dimensões da cultura de segurança do paciente no cotidiano de hospitais de diferentes perfis administrativos: públicos, organizações sociais e privados, e realizar correlação entre as instituições participantes, de acordo com as dimensões da cultura de segurança do paciente utilizadas. MÉTODO Estudo transversal de aspecto quantitativo obtido por meio da aplicação do instrumento Self Assessment Questionnaire 30, traduzido para a língua portuguesa. Os dados foram tratados com análise de variância (ANOVA), além das estatísticas descritivas, considerando como de significância estatística valores de p-valor ≤ 0,05. RESULTADOS Segundo a percepção dos participantes do estudo, as dimensões significativas para a cultura de segurança do paciente foram Ambiente de Segurança do Paciente e Aprendizado Organizacional, com poder explicativo de 81%. A média de respostas obtidas evidenciou que nas organizações privadas houve maiores valores atribuídos às questões, porém a correlação entre as dimensões foi mais forte nas organizações públicas. CONCLUSÃO As dimensões da cultura de segurança do paciente têm valores distintos nas diferentes organizações hospitalares e a sua investigação possibilita identificar quais necessitam ser introduzidas ou aprimoradas para maior segurança do paciente

Patient safety in organizational culture as perceived by leaderships of hospital institutions with different types of administration

OBJECTIVE To identify the perceptions of leaderships toward patient safety culture dimensions in the routine of hospitals with different administrative profiles: government, social and private organizations, and make correlations among participating institutions regarding dimensions of patient safety culture used. METHOD A quantitative cross-sectional study that used the Self Assessment Questionnaire 30 translated into Portuguese. The data were processed by analysis of variance (ANOVA) in addition to descriptive statistics, with statistical significance set at p-value ≤ 0.05. RESULTS According to the participants' perceptions, the significant dimensions of patient safety culture were 'patient safety climate' and 'organizational learning', with 81% explanatory power. Mean scores showed that among private organizations, higher values were attributed to statements; however, the correlation between dimensions was stronger among government hospitals. CONCLUSION Different hospital organizations present distinct values for each dimension of patient safety culture and their investigation enables professionals to identify which dimensions need to be introduced or improved to increase patient safety.OBJETIVO Identificar percepciones de los liderazgos acerca de las dimensiones de la cultura de seguridad del paciente en el cotidiano de hospitales de distintos perfiles administrativos: públicos, organizaciones sociales y privados, y realizar la correlación entre las instituciones participantes, de acuerdo con las dimensiones de la cultura de seguridad del paciente utilizadas. MÉTODO Estudio transversal de aspecto cuantitativo obtenido por medio de la aplicación del instrumento Self Assessment Questionnaire 30, traducido a la lengua portuguesa. Los datos fueron tratados con análisis de varianza (ANOVA), además de las estadísticas descriptivas, considerando como de significación estadística valores de p-valor ≤ 0,05. RESULTADOS Según la percepción de los participantes del estudio, las dimensiones significativas para la cultura de seguridad del paciente fueron Ambiente de Seguridad del Paciente y Aprendizaje Organizativo, con poder explicativo del 81%. El promedio de respuestas obtenidas evidenció que en las organizaciones privadas hubo mayores valores atribuidos a las cuestiones, sin embargo la correlación entre las dimensiones fue más fuerte en las organizaciones públicas. CONCLUSIÓN Las dimensiones de la cultura de seguridad del paciente tienen valores distintos en las diferentes organizaciones hospitalarias y su investigación posibilita identificar cuáles necesitan introducirse o perfeccionarse para una mayor seguridad del paciente.OBJETIVO Identificar percepções das lideranças sobre as dimensões da cultura de segurança do paciente no cotidiano de hospitais de diferentes perfis administrativos: públicos, organizações sociais e privados, e realizar correlação entre as instituições participantes, de acordo com as dimensões da cultura de segurança do paciente utilizadas. MÉTODO Estudo transversal de aspecto quantitativo obtido por meio da aplicação do instrumento Self Assessment Questionnaire 30, traduzido para a língua portuguesa. Os dados foram tratados com análise de variância (ANOVA), além das estatísticas descritivas, considerando como de significância estatística valores de p-valor ≤ 0,05. RESULTADOS Segundo a percepção dos participantes do estudo, as dimensões significativas para a cultura de segurança do paciente foram Ambiente de Segurança do Paciente e Aprendizado Organizacional, com poder explicativo de 81%. A média de respostas obtidas evidenciou que nas organizações privadas houve maiores valores atribuídos às questões, porém a correlação entre as dimensões foi mais forte nas organizações públicas. CONCLUSÃO As dimensões da cultura de segurança do paciente têm valores distintos nas diferentes organizações hospitalares e a sua investigação possibilita identificar quais necessitam ser introduzidas ou aprimoradas para maior segurança do paciente

Field emission from two-dimensional GeAs

GeAs is a layered material of the IV-V groups that is attracting growing attention for possible applications in electronic and optoelectronic devices. In this study, exfoliated multilayer GeAs nanoflakes are structurally characterized and used as the channel of back-gate field-effect transistors. It is shown that their gate-modulated p-type conduction is decreased by exposure to light or electron beam. Moreover, the observation of a field emission current demonstrates the suitability of GeAs nanoflakes as cold cathodes for electron emission and opens up new perspective applications of two-dimensional GeAs in vacuum electronics. Field emission occurs with a turn-on field of ~80 V/{\mu}m and attains a current density higher than 10 A/cm^2, following the general Fowler-Nordheim model with high reproducibility.Comment: 10 pages, 3 figure

Plataforma telemàtica de serveis administratius de l'Ajuntament de Ripollet

PTSA és el projecte resultat del desenvolupament de la Plataforma Telemàtica de Serveis Administratius proposada com a iniciativa per l'Ajuntament de Ripollet. Amb l'objectiu de promoure la utilització dels canals de comunicació segurs entre el ciutadà i l'Administració, aporta els serveis d'acreditació, registre i consulta. Integrada amb el portal ripollet.cat, implementa les tecnologies per al tractament de l'acreditació d'usuaris mitjançant certificació digital i la generació dinàmica de documents signats electrònicament. Dins el marc d'execució de la llei 11/2007 d'accés electrònic dels ciutadans als serveis públics, és un gran primer pas en el llarg camí amb destinació a una Administració electrònica completa i de qualitat.PTSA es el proyecto resultado del desarrollo de la Plataforma Telemática de Servicios Administrativos propuesta como iniciativa por el Ayuntamiento de Ripollet. Con el objetivo de promover el uso de los canales de comunicación seguros entre el ciudadano y la Administración, aporta los servicios de acreditación, registro y consulta. Integrada con el portal ripollet.cat, implementa las tecnologías para el tratamiento de la acreditación de usuarios mediante certificación digital y la generación dinámica de documentos firmados electrónicamente. En el ámbito de ejecución de la ley 11/2007 de acceso electrónico de los ciudadanos a los servicios públicos, se trata de un primer gran paso en el largo camino con destino a una Administración electrónica completa y de calidad.PTSA is the project obtained as a result of the ICT Platform Development of the Administrative Services as an initiative of Ripollet City Council. This project emerged in order to encourage the use of reliable communication channels between the citizen and the Civil Service. Moreover, it contributes the registering, accreditation and consulting process. Integrated into ripollet.cat web site, it implements technologies for the user accreditation treatment through digital certification and dynamic generation of electronic signed documents. In the implementation field of 11/2007 law about the citizens' electronic access to Public Services, it is a big first step forward in the long way to a complete and quality electronic Administration