Structure-dependent electrical properties of graphene nanoribbon devices with graphene electrodes

Graphene nanoribbons (GNRs) are a novel and intriguing class of materials in the field of nanoelectronics, since their properties, solely defined by their width and edge type, are controllable with high precision directly from synthesis. Here we study the correlation between the GNR structure and the corresponding device electrical properties. We investigated a series of field effect devices consisting of a film of armchair GNRs with different structures (namely width and/or length) as the transistor channel, contacted with narrowly spaced graphene sheets as the source-drain electrodes. By analyzing several tens of junctions for each individual GNR type, we observe that the values of the output current display a width-dependent behavior, indicating electronic bandgaps in good agreement with the predicted theoretical values. These results provide insights into the link between the ribbon structure and the device properties, which are fundamental for the development of GNR-based electronics.Comment: Published in Carbon (2019

Energía solar térmica de concentración, tecnología eficiente, sustentable y gestionable en la República Argentina

El moderno concepto que se aplica hoy a las energías renovables, por el cual estas deben ser eficientes, limpias y gestionables, tiene su máximo exponente en la energía solar térmica de concentración. Este tipo de tecnología solar es la única gestionable las veinticuatro horas continuas, con un 75 % del valor agregado en productos de industria nacional. Se utiliza para ello, el almacenamiento de sales térmicas. Desde el año 2012, la Universidad Nacional de La Plata y la Comisión de Investigaciones Científicas de la provincia de Buenos Aires, a través de sus laboratorios LOCE y CEMECA, vienen desarrollando varios proyectos de I+D+i1 en generación de energía eléctrica y calor de proceso industrial con esta tecnología. En este trabajo, se muestran los estudios hechos en: diseños experimentales, materiales nacionales, métodos de determinación y medición, áreas de solarimetría accesibles, así como aplicaciones posibles. La Plataforma Solar de Almería, en España, es un centro de desarrollo tecnológico para la investigación de equipos, tecnologías y referencias en estas tecnologías, con el cual la UNLP ha firmado programas de capacitación y formación de recursos humanos, así como un programa específico de la Red CyTED, para el desarrollo de sistemas de energía solar térmica de concentración combinando híbridos con biomasa.Trabajo presentado por el Centro de Investigación en Metrología y Calidad (CEMECA

Fabrication of three terminal devices by ElectroSpray deposition of graphene nanoribbons

Electrospray deposition (ESD) in ambient conditions has been used to deposit graphene nanoribbons (GNRs) dispersed in liquid phase on different types of substrates, including ones suitable for electrical transport. The deposition process was controlled and optimized by using Raman spectroscopy, Scanning Probe Microscopies and Scanning Electron Microscopy. When deposited on graphitic electrodes, GNRs were used as semi-conducting channel in three terminal devices showing gate tunability of the electrical current. These results suggest that ESD technique can be used as an effective tool to deposit chemically synthesized GNRs onto substrates of interest for technological applications

Coronaviruses Detected in Brazilian Wild Birds Reveal Close Evolutionary Relationships with Beta- and Deltacoronaviruses Isolated From Mammals

This study showed that the most of the coronaviruses (CoVs) detected in Brazilian wild birds clustered with the mouse hepatitis virus A59 strain, belonging to the BetaCoV group. Furthermore, CoV detected in two different bird species, Amazona vinacea and Brotogeris tirica, clustered with a CoV isolated from Sparrow (SpaCoV HKU17) belonging to a monophyletic group related with the CoVs isolated from swines (PorCoV HKU15), both belonging to the DeltaCoV genus, previously unreported in South America. Considering the risk of inter-species host switching and further adaptation to new hosts, detection in bird species of CoVs closely related to mammal CoVs should warn for the potential emergence of new threatening viruses.Fundação de Amparo à Pesquisa do Estado de São Paulo (Grants 2013/03922-6 and 2011/50919-5

Convolution kernels versus spectral multipliers for sub-Laplacians on groups of polynomial growth

Let $\mathcal{L}$ be a sub-Laplacian on a connected Lie group $G$ of polynomial growth. It is well known that, if $F : \mathbb{R} \to \mathbb{C}$ is in the Schwartz class $\mathcal{S}(\mathbb{R})$, then the convolution kernel $\mathcal{K}_{F(\mathcal{L})}$ of the operator $F(\mathcal{L})$ is in the Schwartz class $\mathcal{S}(G)$. Here we prove a sort of converse implication for a class of groups $G$ including all solvable noncompact groups of polynomial growth. We also discuss the problem whether integrability of $\mathcal{K}_{F(\mathcal{L})}$ implies continuity of $F$.Comment: 27 page

Biological Random Walks: multi-omics integration for disease gene prioritization

Motivation: Over the past decade, network-based approaches have proven useful in identifying disease modules within the human interactome, often providing insights into key mechanisms and guiding the quest for therapeutic targets. This is all the more important, since experimental investigation of potential gene candidates is an expensive task, thus not always a feasible option. On the other hand, many sources of biological information exist beyond the interactome and an important research direction is the design of effective techniques for their integration. Results: In this work, we introduce the Biological Random Walks (BRW) approach for disease gene prioritization in the human interactome. The proposed framework leverages multiple biological sources within an integrated framework. We perform an extensive, comparative study of BRW's performance against well-established baselines. Availability and implementation: All code is publicly available and can be downloaded at \url{https://github.com/LeoM93/BiologicalRandomWalks}. We used publicly available datasets, details on their retrieval and preprocessing are provided in the supplementary material

A cláusula perfil no contrato de seguro de automóveis

As injustiça sociais perpetradas pela concepção liberal de mundo provocaram a derrocada da concepção tradicional do contrato. Instaurou-se uma nova ordem contratual, acompanhada do surgimento de novos princípios contendores da outrora irrestrita autonomia da vontade e autorizadores da intervenção estatal no domínio económico para a proteção do contratante mais frágil. Essa nova ordem ganhou destaque no Código de Defesa do Consumidor, o qual prevê a possibilidade de controle, pelo Poder Judiciário, das cláusulas que provocam desequilíbrio contratual. Nesse contexto, têm sido cada vez mais frequente a declaração de nulidade da cláusula perfil existente nos contratos de seguro de automóveis e a compreensão restritiva do que seja "agravação do risco", sempre com o escopo de proteger o segurado-consumidor. Entretanto, tendo-se em vista as necessidades de observar-se o princípio do mutualismo, de manter-se a dependência estreita entre o risco e o prémio e de fazer com que o prémio pago por cada segurado seja proporcional aos riscos que atingem seu interesse, a cláusula perfil não pode ser considerada uma cláusula abusiva porque ela não limita direitos instituídos pelo contrato para o segurado, mas apenas restringe previamente os riscos assumidos pelo segurador. Sua inclusão no contrato de seguro de automóveis é necessária e possível, desde que seja redigida com as cautelas exigidas pela lei consumerista e desde que sejam feitos ao segurado os esclarecimentos pertinentes