The fictitious domain method and applications in wave propagation

International audienceThis paper deals with the convergence analysis of the fictitious domain method used for taking into account the Neumann boundary condition on the surface of a crack (or more generally an object) in the context of acoustic and elastic wave propagation. For both types of waves we consider the first order in time formulation of the problem known as mixed velocity-pressure formulation for acoustics and velocity-stress formulation for elastodynamics. The convergence analysis for the discrete problem depends on the mixed finite elements used. We consider here two families of mixed finite elements that are compatible with mass lumping. When using the first one which is less expensive and corresponds to the choice made in a previous paper, it is shown that the fictitious domain method does not always converge. For the second one a theoretical convergence analysis was carried out in [7] for the acoustic case. Here we present numerical results that illustrate the convergence of the method both for acoustic and elastic waves

Computational Analysis of Distance Operators for the Iterative Closest Point Algorithm

The Iterative Closest Point (ICP) algorithm is currently one of the most popular methods for rigid registration so that it has become the standard in the Robotics and Computer Vision communities. Many applications take advantage of it to align 2D/3D surfaces due to its popularity and simplicity. Nevertheless, some of its phases present a high computational cost thus rendering impossible some of its applications. In this work, it is proposed an efficient approach for the matching phase of the Iterative Closest Point algorithm. This stage is the main bottleneck of that method so that any efficiency improvement has a great positive impact on the performance of the algorithm. The proposal consists in using low computational cost point-to-point distance metrics instead of classic Euclidean one. The candidates analysed are the Chebyshev and Manhattan distance metrics due to their simpler formulation. The experiments carried out have validated the performance, robustness and quality of the proposal. Different experimental cases and configurations have been set up including a heterogeneous set of 3D figures, several scenarios with partial data and random noise. The results prove that an average speed up of 14% can be obtained while preserving the convergence properties of the algorithm and the quality of the final results

Normas Internacionales de Auditoria NIA : Aplicación de las normas internacionales de auditoria 705 (REVISADA) opinión modificada en el informe de auditoria emitido por un auditor independiente y 706 (REVISADA) párrafos de enfasís y párrados sobre otros cuestiones en la auditoria a los estados financieros al 31 de diciembre de 2016 a la empresa AGROMAR,S.A

El presente seminario de graduación tiene como propósito la realización de una auditoria a los estados financieros de la empresa AGROMAR, S.A. al 31 de Diciembre de 2016 con énfasis a las cuentas por cobrar aplicando de forma práctica las Normas Internacionales de Auditoria como una herramienta necesaria en la profesión contable que tiene como finalidad ayudar al auditor a alcanzar una seguridad razonable en su opinión sobre la evaluación de los estados financieros; 705 (Revisadas) que contempla tres tipos de opiniones modificadas; con salvedad, adversa y abstención, y 706 (Revisadas) la cual establece el uso de los párrafos de énfasis o de un párrafo sobre otras cuestiones en el informe de auditoría de acuerdo a su naturaleza o a su significatividad de la información que se va a comunicar. Hemos desarrollado un amplio concepto sobre las Normas Internacionales de Auditoría y lo que estas indican para la práctica de un profesional contable, considerando los distintos aspectos para poder llevar a cabo una auditoria a los estados financieros, su estructura considerada y avalada por el Colegio de Contadores Públicos de Nicaragua (CCPN). Por medio de la revisión sistemática de los diferentes programas, procedimientos y controles operativos, finalizamos con las recomendaciones y conclusiones de acuerdo a los resultados obtenidos

Convergence analysis and validation of low cost distance metrics for computational cost reduction of the Iterative Closest Point algorithm

The Iterative Closest Point algorithm (ICP) is commonly used in engineering applications to solve the rigid registration problem of partially overlapped point sets which are pre-aligned with a coarse estimate of their relative positions. This iterative algorithm is applied in many areas such as the medicine for volumetric reconstruction of tomography data, in robotics to reconstruct surfaces or scenes using range sensor information, in industrial systems for quality control of manufactured objects or even in biology to study the structure and folding of proteins. One of the algorithm’s main problems is its high computational complexity (quadratic in the number of points with the non-optimized original variant) in a context where high density point sets, acquired by high resolution scanners, are processed. Many variants have been proposed in the literature whose goal is the performance improvement either by reducing the number of points or the required iterations or even enhancing the complexity of the most expensive phase: the closest neighbor search. In spite of decreasing its complexity, some of the variants tend to have a negative impact on the final registration precision or the convergence domain thus limiting the possible application scenarios. The goal of this work is the improvement of the algorithm’s computational cost so that a wider range of computationally demanding problems from among the ones described before can be addressed. For that purpose, an experimental and mathematical convergence analysis and validation of point-to-point distance metrics has been performed taking into account those distances with lower computational cost than the Euclidean one, which is used as the de facto standard for the algorithm’s implementations in the literature. In that analysis, the functioning of the algorithm in diverse topological spaces, characterized by different metrics, has been studied to check the convergence, efficacy and cost of the method in order to determine the one which offers the best results. Given that the distance calculation represents a significant part of the whole set of computations performed by the algorithm, it is expected that any reduction of that operation affects significantly and positively the overall performance of the method. As a result, a performance improvement has been achieved by the application of those reduced cost metrics whose quality in terms of convergence and error has been analyzed and validated experimentally as comparable with respect to the Euclidean distance using a heterogeneous set of objects, scenarios and initial situations

Oxidação catalítica da água: catalisadores organometálicos de ferro

Dissertação para obtenção do Grau de Mestre em Engenharia Química e BioquímicaA criação de catalisadores capazes de catalisar a reação de splitting da água, nomeadamente a oxidação da água são fundamentais para o desenvolvimento de sistemas capazes de produzir hidrogénio molecular, que é considerado um combustível verdadeiramente “verde”. A aplicação de catalisadores baseados em metais de transição preciosos como o irídio e o ruténio, já é conhecida em catálise da oxidação da água. No entanto a sua relativa toxicidade e escassez na crosta terreste tornam vantajosa a procura de novos catalisadores baseados em metais de transição da primeira linha da tabela periódica, os quais são benignos e mais abundantes na crosta terreste. O ferro é um exemplo deste tipo de metais e o seu uso em catálise para oxidação da água já foi provada, mas encontra-se ainda muito pouco explorada. O desenvolvimento destes catalisadores baseados em ferro podem vir a tornar possível o uso de sistemas catalíticos à grande escala, resolvendo potencialmente parte dos problemas energéticos do nosso planeta

Amamentação de mulheres trabalhadoras inscritas em unidades de saúde de meio urbano e rural

La combinación de los roles de madre y mujer asalariada en áreas urbanas o rurales puede ser un obstáculo para la lactancia materna. Se desarrolló un estudio descriptivo y transversal con 79 madres, que se registraron en una Unidad de Salud Familiar de un área urbana y ocho centros de salud rurales. La recolección de datos se realizó mediante un cuestionario, que se administró a una muestra de conveniencia compuesta de madres que mantuvieron la lactancia después de regresar a sus puestos de trabajo. Se tenía la intención de estudiar el mantenimiento de la lactancia materna exclusiva y total de madres registradas en Unidades de Salud Familiar urbanas y rurales, después de volver a sus puestos de trabajo. El 7,6% de las madres mantuvo la leche materna hasta los seis meses de edad y sólo el 1,3% estuvo amamantados hasta los 18 meses. Sólo el 13,9% hizo la introducción a los 6 meses de edad y el 34,2% de las madres informó que la vuelta al trabajo era la principal causa de la introducción de otros alimentos en la dieta del niño, además de la leche de las mujeres. Nuestros resultados están en buen acuerdo con el estudio desarrollado por Pedroso y otros (2011), que llegó a la conclusión de que el 34,8% de las madres mantiene la lactancia de su hijo durante más de 6 meses después de la vuelta al trabajo. Se requiere que sociedad mire a la lactancia materna como una tarea productiva y significativa, desarrollando acciones educativas que aborden la importancia y las ventajas de la lactancia materna exclusiva.Combining the roles of mother and employed woman in urban or rural areas can be a hurdle to the breastfeeding. It was developed a descriptive and transversal study with 79 mothers, who were registered in a Family Health Unit from one urban and eight rural health centres. The data collection was carried out using a questionnaire, which was administered to a convenience sample composed of mothers who remained breastfeeding after coming back to their jobs. It was intended to study the maintenance of exclusive and total breastfeeding of mothers registered in urban and rural Family Health Units, after coming back to their jobs. 7.6% of mothers breastfed up to six months of age and only 1.3 % breastfed up to 18 months. Only 13.9% made the introduction at 6 months of age and 34.2% of mothers reported the return to work as the main cause for the introduction of other food in the child diet, besides the women milk. Our results are in good agreement with the study developed by Pedroso et al (2011), who concluded that 34.8% of mothers kept child’s breastfeeding for more than 6 months after the return to work. It will be required that the society look to breastfeeding as productive and significant work, developing educational actions which address the importance and the advantages of exclusive breastfeeding.Conciliar as funções maternas com as funções de mulher trabalhadora em meio urbano ou rural pode ser um obstáculo à amamentação. Desenvolveu-se um estudo descritivo e transversal junto de 79 mães, inscritas numa Unidade de Saúde Familiar (USF), de um Centro de Saúde urbano e 8 Centros de Saúde de meio rural. A recolha de dados foi realizada através de um formulário aplicado a uma amostra de conveniência constituída por mães que se encontravam a amamentar quando regressaram ao trabalho. Pretendeu-se estudar a manutenção da amamentação exclusiva e total, de mães inscritas em Unidades de Saúde de meio urbano e rural, após regresso ao trabalho. 7.6% amamentou até aos 6 meses e apenas 1.3% das mães amamentou até aos 18 meses de idade. Apenas 13.9% fez a introdução aos 6 meses de idade, e 34.2% das mães referiram o regresso ao trabalho como primeiro motivo para a introdução de outros alimentos na dieta da criança, para além do leite materno. Os nossos resultados vão de encontro ao estudo de Pedroso (2011), que concluiu que apenas 34.8% das mães continuaram a amamentar o filho durante mais de 6 meses, após o regresso ao trabalho. Será necessário que a sociedade considere o aleitamento materno como um trabalho produtivo e significativo, realizando educações à população em geral acerca da importância e vantagens da amamentação exclusiva.peerReviewe

When expectancies harm comprehension : Encoding flexibility in impression formation

Peer reviewedPostprin

A amamentação de mulheres trabalhadoras e alunas de instituições do Ensino Superior publico de Coimbra

La vuelta al trabajo ha sido mencionada por las madres que trabajan como causa de la interrupción de la lactancia materna. Se desarrolla un estudio descriptivo transversal para estudiar las prácticas y las limitaciones de la lactancia materna entre madres/estudiantes que regresan al trabajo/actividades escolares en Instituciones Superiores públicas en Coimbra, así como evaluar los factores que facilitan/impiden el mantenimiento de la lactancia materna. Se aplicó un cuestionario a una muestra de 109 madres trabajadoras y 121 estudiantes, con niños sanos nacidos en los últimos cinco años y una edad gestación por encima de 34 semanas. Se concluyó que sólo el 34,8% de las madres continuaron amamantando más de seis meses después de regresar al trabajo y 27,8% lo hizo menos de un mes, 57,8% sacando y almacenando leche materna, 62.2% ejercieron sus derechos como madre/estudiante en el trabajo, 72,2% no dio de amamantar durante las horas del trabajo, 95.7% no contaba con nadie que pudiera llevar a sus hijos al trabajo para ser amamantados, y 54,3% experimentó limitaciones personales para mantener la lactancia materna. Los compañeros de trabajo/escuela (92.6%) y superiores y profesores (84.8%) conocían sobre la lactancia materna. Las madres que tenían apoyo de la familia (64.7%) y de sus compañeros (64,8%) facilitaron la situación en el trabajo (58,6%) y las no se sentían cansadas (52,5%) continuaron amamantando durante un periodo más largo de tiempo. Esto es importante para aumentar el conocimiento que deben tener las instituciones de educación acerca de la importancia de continuar amamantando a estas edades y el hecho de que todas las madres/estudiantes trabajadoras deben tener las condiciones necesarias y el apoyo que les permita seguir a amamantando.The return to work has been mentioned by working mothers as a cause of breastfeeding cessation. A cross-sectional descriptive study was developed to study the practices and constraints to breastfeeding among working mothers/students after returning to work/school activities in public higher institutions in Coimbra, as well as to assess the factors which facilitate/impede the maintenance of breastfeeding. A questionnaire was applied to a sample of 109 working mothers and 121 students, with healthy children born in the past five years and a gestational age above 34 weeks. It was concluded that only 34.8% of the mothers continued to breastfeed for more than six months after returning to work and 27.8% did it for less than one month, 57.8% pumped and stored breast milk, 62.2% exercised their working mother/student rights, 72.2% did not travel during work hours to breastfeed, 95.7% had no one to bring their child to work to breastfeed, and 54.3% experienced personal constraints to maintain breastfeeding. Work/school colleagues (92.6%) and superiors/teachers (84.8%) knew about the breastfeeding. Mothers who had support from the family (64.7%) and from colleagues (64.8%), with a facilitating situation at work (58.6%) and that did not feel tired (52.5%) continued to breastfeed for a longer period of time. It will be important to raise the awareness of education institutions about the importance of continuing to breastfeed and the fact that all working mothers/students should have the necessary conditions and support to continue to breastfeed.peerReviewe

Amamentação em mulheres trabalhadoras e alunas do ensino superior público de Coimbra

Desarrollamos un estudio descriptivo de corte transversal en las Instituciones Públicas de Educación Superior de Coimbra que prentende estudiar las prácticas y de los límites de la lactancia materna en madres trabajadoras y estudiantes después de su regreso al trabajo o a las actividades académicas; evaluar los factores que facilitan o dificultan mantener la lactancia; verificar si las instituciones promueven la lactancia materna; y describir experiencias de lactancia de las madres. Se aplicó un cuestionario a las madres que estaban amamantando, así como una entrevista semiestructurada a éstas, a los presidentes de los consejos pedagógicos y a los coordinadores Recursos Humanos. De acuerdo con el estudio cuantitativo, las madres con apoyo de la familia y de algunos colegas, con facilidades en el lugar de trabajo y sin cansancio, tenderán a continuar con la lactancia. Para el estudio cualitativo, la lactancia materna se consideró como un momento de relación madre-hijo y de compartir, generando beneficios físicos y emocionales para la salud de ambos. La viabilidad, la flexibilización de horarios, el apoyo familiar, la existencia de recursos materiales, el espacio físico y el cumplimiento de la legislación fueron considerados factores facilitadores. Como dificultadores a la adaptación al trabajo y a las actividades académicas, la falta de flexibilidad de horarios, el estrés y la fatiga, la falta de un jardín de infancia o centro de cuidado infantil, la ausencia de una habitación con una nevera, la falta de apoyo familiar, los aspectos sociales, los aspectos relacionados con los profesionales de la salud, las sanciones, la falta de apoyo psicológico y el dilema entre mantener la lactancia materna o volver a las actividades profesional o académicas.Desenvolvemos um estudo descritivo/transversal em Instituições Públicas do Ensino Superior de Coimbra que pretende estudar práticas e limites à amamentação em mulheres trabalhadoras/alunas após regresso ao trabalho/atividades escolares, avaliar os fatores que facilitam/dificultam a manutenção da amamentação, verificar se as Instituições são promotoras da amamentação e descrever as vivências de amamentação das mães. Aplicámos um questionário às mães que ainda amamentavam e uma entrevista semi-estruturada a estas, aos Presidentes dos Conselhos Pedagógicos e aos Responsáveis pelos Recursos Humanos. Segundo o estudo quantitativo, as mães com apoio familiar e/ou dos colegas, com alguma condição facilitadora no local de trabalho e sem cansaço, tenderam a manter a amamentação. Pelo estudo qualitativo, a amamentação foi considerada um momento de relação mãe-filho e de partilha, trazendo benefícios físicos e emocionais para a saúde de ambos. A praticabilidade, flexibilização de horário, apoio familiar, existência de recursos materiais, espaço físico e cumprimento da legislação foram considerados fatores facilitadores. Como dificultadores a adaptação ao trabalho/atividades escolares, não flexibilidade de horário, stress/cansaço, ausência de infantário/creche, ausência de sala com frigorífico, ausência de apoio familiar, aspetos sociais, aspetos relativos aos profissionais de saúde, penalizações, ausência de apoio psicológico e o dilema em manter a amamentação e rei- niciar as atividades profissionais/escolares.A descriptive cross-sectional study was carried out in Public Higher Education Institutions in Coimbra. It aimed to: study the practices and limits to breastfeeding in working mothers/students after their return to work/academic activities; assess the factors which facilitate/hinder breastfeeding maintenance; observe if the institutions promote breastfeeding; and describe mothers’ breastfeeding experiences. A questionnaire was applied to mothers who were still breastfeeding, as well as a semistructured interview to those, the Presidents of Pedagogical Boards and Human Resources coordinators. According to the quantitative study, mothers with family support and colleagues, some facilitating condition at the workplace and those who weren’t tired continued to breastfeed. For the qualitative study, breastfeeding was considered as a moment of mother-son relationship and sharing, with physical and emotional benefits to both mothers’ and children’s health. Some facilitating factors included practicability, schedule flexibility, family support, existence of material resources, physical space, legal compliance; while some hindering factors included adaptation to work/academic activities, lack of schedule flexibility, stress/fatigue, lack of a kindergarten/daycare center, lack of a room with a fridge, lack of family support, social aspects, aspects related to health professionals, penalties, lack of psychological support and dilemma between continuing to breastfeed and return to professional/academic activities

A Quantitative Comparison of Calibration Methods for RGB-D Sensors Using Different Technologies

RGB-D (Red Green Blue and Depth) sensors are devices that can provide color and depth information from a scene at the same time. Recently, they have been widely used in many solutions due to their commercial growth from the entertainment market to many diverse areas (e.g., robotics, CAD, etc.). In the research community, these devices have had good uptake due to their acceptable level of accuracy for many applications and their low cost, but in some cases, they work at the limit of their sensitivity, near to the minimum feature size that can be perceived. For this reason, calibration processes are critical in order to increase their accuracy and enable them to meet the requirements of such kinds of applications. To the best of our knowledge, there is not a comparative study of calibration algorithms evaluating its results in multiple RGB-D sensors. Specifically, in this paper, a comparison of the three most used calibration methods have been applied to three different RGB-D sensors based on structured light and time-of-flight. The comparison of methods has been carried out by a set of experiments to evaluate the accuracy of depth measurements. Additionally, an object reconstruction application has been used as example of an application for which the sensor works at the limit of its sensitivity. The obtained results of reconstruction have been evaluated through visual inspection and quantitative measurements