Statistical Mechanics Characterization of Neuronal Mosaics

The spatial distribution of neuronal cells is an important requirement for achieving proper neuronal function in several parts of the nervous system of most animals. For instance, specific distribution of photoreceptors and related neuronal cells, particularly the ganglion cells, in mammal's retina is required in order to properly sample the projected scene. This work presents how two concepts from the areas of statistical mechanics and complex systems, namely the \emph{lacunarity} and the \emph{multiscale entropy} (i.e. the entropy calculated over progressively diffused representations of the cell mosaic), have allowed effective characterization of the spatial distribution of retinal cells.Comment: 3 pages, 1 figure, The following article has been submitted to Applied Physics Letters. If it is published, it will be found online at http://apl.aip.org

Diagnóstico da hepatite por vírus C em doadores de sangue brasileiros, usando a reação de transcrição reversa e a reação em cadeia da polimerase "nested": comparação com os ensaios imunoenzimáticos e imunoblot recombinante

Screening blood donations for anti-HCV antibodies and alanine aminotransferase (ALT) serum levels generally prevents the transmission of hepatitis C virus (HCV) by transfusion. The aim of the present study was to evaluate the efficiency of the enzyme immunoassay (EIA) screening policy in identifying potentially infectious blood donors capable to transmit hepatitis C through blood transfusion. We have used a reverse transcriptase (RT)-nested polymerase chain reaction (PCR) to investigate the presence of HCV-RNA in blood donors. The prevalence of HCV-RNA positive individuals was compared with the recombinant immunoblot assay (RIBA-2) results in order to assess the usefulness of both tests as confirmatory assays. Both tests results were also compared with the EIA-2 OD/C ratio (optical densities of the samples divided by the cut off value). ALT results were expressed as the ALT quotient (qALT), calculated dividing the ALT value of the samples by the maximum normal value (53UI/l) for the method. Donors (n=178) were divided into five groups according to their EIA anti-HCV status and qALT: group A (EIA >; or = 3, ALT; or = 3, ALT>;1), group C (1Na prevenção da transmissão de Hepatite por Vírus C (HCV) em transfusões de hemocomponentes, utiliza-se rotineiramente, como testes de triagem de doadores de sangue, ensaios que detectam anticorpos anti-HCV e dosagens da enzima alanina-aminotransferase (ALT). O presente estudo tem como objetivo principal avaliar a eficiência do ensaio imunoenzimático de segunda geração (EIA-2) como teste de triagem, na identificação de doadores de sangue potencialmente infectados, e portanto, capazes de transmitir hepatite C pelos hemocomponentes. Nós utilizamos o ensaio de transcrição reversa (RT) e a reação em cadeia da polimerase "nested" («nested PCR») para investigar a presença do RNA do vírus da hepatite C (HCV) em doadores de sangue. A prevalência do RNA-HCV em indivíduos positivos foi comparada com os resultados do ensaio complementar imunoblot recombinante de segunda geração (RIBA-2) com o intuito de avaliar a utilidade de ambos como testes confirmatórios. Estes dois testes também foram comparados com a razão DO/C (valores de densidade óptica das amostras dividida pelo valor de corte da reação) no EIA-2. Os resultados das dosagens da ALT foram expressos como uma razão unitária denominada qALT, que representa o cálculo do valor do ALT da amostra dividido pelo valor máximo considerado normal para o teste (53UI/L). Os doadores de sangue foram divididos em cinco grupos de acordo com os resultados do EIA-2 e o qALT: grupo A (EIA >; ou = 3, ALT; ou = 3, ALT>;1), grupo C (

Memoria republicana y memoria católica. Cuestión religiosa y conmemoración pública en la Barcelona republicana (1931-1936)

Este artículo aborda el debate sobre la cuestión religiosa en la Barcelona republicana desde una nueva perspectiva. En concreto, estudia cómo la memoria pública fue un escenario simbólico privilegiado para el pulso entre el paradigma laico y el paradigma católico. El autor analiza el despliegue de un nuevo relato conmemorativo republicano, nacionalista, obrerista y laico. Describe la secularización del tiempo y del espacio que llevaron a cabo las élites políti-cas y culturales de la ciudad, comandadas por ERC. Sostiene, sin embargo, que en el trasfondo de la nueva memoria republicana subyace una gramática y una semántica narrativa de resonancias judeocristianas. Al mismo tiempo, remarca el esfuerzo de la ciudadanía católica por mantener su visibilidad en el espacio público, precisamente a través de la vindicación de la propia cultura de memoria. El autor estudia también el posicionamiento de las principales fuerzas políticas del momento (Esquerra Republicana de Catalunya y la Lliga Regionalista) ante la cuestión religiosa, así como su distinta hermenéutica de la tradición catalana. Esta investigación se lleva a cabo con una amplia gama de fuentes periodísticas, bibliográficas y administrativas de la época. El texto se aproxima a la relación entre republicanismo y catolicismo desde un prisma innovador y ofrece una nueva panorámica sobre los imaginarios sociales y la actividad política en la Barcelona de la Segunda República

The structure of information in the internationalization processes of universities

In this work we were interested in the relation between internationalization of universities and the information demands associated with it. The internationalization process of universities is accompanied by a process of dissemination of information, which fulfills several purposes. The aim of this work was to evaluate, in a systematic way, the international indicators and rankings that are proposed in the literature and that are used by the higher education institutions (HEI), and to propose an information model based on that analysis. The research methodology was based on a literature review, documental analysis, informal interviews and observation of events related to internationalization of universities. An exercise of compilation, analysis and synthesis of indicators of the internationalization process of universities resulted in the proposal of a structure of information that includes the most common used indicators, and that can be related to the various perspectives that drive the internationalization process. The structure can be used to guide the process of construction of models of information by universities, particularly in the process of design of web pages, which is nowadays a preferred vehicle of information dissemination from the part of the universities and of information gathering from the part of entities interested in universities.This work has been supported by FCT -Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Automatic control system for an oil-hydraulic actuator of a scissor lift

Lifting equipment’s have the purpose to lift goods within their safe working load and design rules specified in standards. However, some applications require additional care regarding handling the load when this care is out of the standard’s specifications. This paper presents the control and supervision system development of a scissor lift table, which should ensure, during its motion, that the vertical speed is constant. This lift table is working alongside a system for handling boxes composed by 3 entry conveyors and 1 exit conveyor. In this work, it was carried out the study of the direct and inverse kinematics to obtain the equations of position, speed and force for the oil-hydraulic actuator and the applicability of Denavit-Hartenberg’s algorithm for these equations. It was proposed a hydraulic circuit, with the selection of the main hydraulic components and the design of the oil-hydraulic actuator (a cylinder) with the magnetostrictive transducer as well. A programmable logical controller was selected, as well as the sensors and actuators for the conveyor system and a program was developed which allows to automatically control the system. The lift table’s velocity control is done by equations which define an oil flow profile of the hydraulic cylinder, which ensures a constant vertical speed of the lift table. To improve the control of the system, initial and final flow ramps were added to the equations, with reduced oil flow at the target height. It was observed that the use of Denavit-Hartenberg’s algorithm revealed to be limited, on which it was necessary to use other calculation methods to obtain the equations of speed and force. However, the proposed oil-hydraulic circuit, as well as the developed speed control, allow the control of the lift table’s position and speed.info:eu-repo/semantics/publishedVersio

Characterization of the structural, thermal, mechanical and electrical properties of bacterial cellulose

Although chemically similar to plant cellulose, bacterial cellulose (BC) produced by Gluconoacetobacter xylinum, a strict aerobe bacteria, is chemically pure, as is deprived of non-cellulosic polysaccharides (Jonas et al., 1998; Vandamme et al., 1998; Klemm et al., 2001; Amano, et al., 2005; Helenius et al., 2006). Its unique properties include high water holding capacity, high crystallinity, ultrafine fiber network, high tensile strength in the wet state, the ability to be shaped into 3D structures during synthesis (in-situ moldability) and excellent shape retention (Klemm et al., 2001; Helenius et al., 2006). The unique properties provided by the nanomeric structure of BC offer a wide range of applications such as in the human and veterinary medicine, odonthology, pharmaceutical industry, acoustic and filter membranes, biotechnological devices and in the food and paper industry. This work is focused on the production and characterization of bacterial cellulose from Gluconoacetobacter xylinus (ATCC 53582 and ATCC 10245 strains) concerning its structural, thermal, mechanical, electrical and morphological properties

Bot’n roll robotic kit as a learning tool for youngsters

Activities involving robotics, projecting assembling and programming robots are in essence hands-on and inquiry-based activities leading to an effective learning of different aspects of science and technology among others. Different approaches have being used to introduce robotics in the education of young children. In this communication we will present an approach that in an inquiry based science education, IBSE, perspective, uses an informal environment to introduced robotics, as well as a range of other science and technology, concepts and competencies to young students. Many youngsters are getting interested on general technology and the robotics field in particular. Even though their knowledge is very basic they are very enthusiastic and willing to learn quickly. Most robotics events consist of competitions, and that means the youngsters still need guidance by professionals. RoboParty is a different educational robotics event that teaches the participants, with IBSE hands-on techniques, how to build a robot from scratch to program it and in the end they keep the robot they built for themselves for further exploration. Such robot to be built by the young children for the first time needs to be very easy and with a friendly programming language. The Bot’n Roll robotics kit was developed specifically for the RoboParty event, and has since then been improved with more sensors and actuators, which are simple to built and easy to use. The Bot’n Roll robot family launched recently another more complex robot that uses omnidirectional wheels and that can be used on other robotic competitions like world known RoboCup. This paper describes also the Bot’n Roll robots and show how they are built, bearing in mind that these robots were developed for youngsters who never worked with robotics

A dynamic approach to teaching LSS at universities

Alongside the European Students of Industrial Engineering and Management (ESTIEM) a team of students from the University of Minho, in cooperation with a corporate partner, developed a free and scalable Lean Six Sigma (LSS) Green-Belt level course for Engineering students. Purpose: The authors aim to depict how free access to LSS Green-Belt knowledge before graduation can positively impact both engineering education and the students when in real-life projects. The purpose is not to build on existing literature, but to provide a practical teaching structure. Methodology: The authors chose to follow the hypothetico-deductive method which consists of formulating hypotheses and comparing them with real-life brought up from their personal experiences while teaching the course. Findings: This case study found a positive impact on both the students responsible for facilitating the training sessions, as well as the ones receiving practical and theoretical knowledge. With more than 60 course graduates, this model is generating positive results in growing awareness for LSS methods. Practical implications: This paper describes a practical application of a novel approach to teaching LSS in Universities along the obstacles surpassed to design it, blending it in the course curricula. It aims to foster similar implementations in other institutions. Originality: A teaching system built with students for students is scalable, low-cost, and highly engaging. Its deployment not only shows how it is possible to advance education by blending an existing LSS course structure but also how students can greatly benefit from a deeper LSS knowledge before their graduation.(undefined