185 research outputs found

    An updated annotated bibliography on arc routing problems

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    The number of arc routing publications has increased significantly in the last decade. Such an increase justifies a second annotated bibliography, a sequel to Corberán and Prins (Networks 56 (2010), 50–69), discussing arc routing studies from 2010 onwards. These studies are grouped into three main sections: single vehicle problems, multiple vehicle problems and applications. Each main section catalogs problems according to their specifics. Section 2 is therefore composed of four subsections, namely: the Chinese Postman Problem, the Rural Postman Problem, the General Routing Problem (GRP) and Arc Routing Problems (ARPs) with profits. Section 3, devoted to the multiple vehicle case, begins with three subsections on the Capacitated Arc Routing Problem (CARP) and then delves into several variants of multiple ARPs, ending with GRPs and problems with profits. Section 4 is devoted to applications, including distribution and collection routes, outdoor activities, post-disaster operations, road cleaning and marking. As new applications emerge and existing applications continue to be used and adapted, the future of arc routing research looks promising.info:eu-repo/semantics/publishedVersio

    Dissimilar arc routing problems

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    Money collection presents particular problems in terms of effective vehicle routing. Planning the collection or distribution of money for ATMs or parking meters gives rise to two problems: while the total collecting time should be minimized, tours on successive days should be different to prevent robberies. The combination of these two problems is named as the Dissimilar Routing Problem. When the safes to be collected are located along the streets, it corresponds to an arc routing problem, which we call DARP, and when the money is from ATMs, it corresponds to a vehicle routing problem, usually referred to as the peripatetic routing problem. The former problem arises in a Portuguese company in charge of street parking in Lisbon. The firm needs to define tours to collect safes from parking meters, minimizing the total collecting time. To avoid robberies these tours cannot be repeated or somehow anticipated. For this new problem, we present a mixed integer linear programming (MILP) model and develop a matheuristic. Preliminary experiments are provided with data that mimic the real confidential data. Results point to a good performance of the matheuristic, while the smaller instances can be solved to optimality with the MILP model and a commercial solver.info:eu-repo/semantics/publishedVersio

    Arc routing with trip-balancing and attractiveness measures : A waste collection case study

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    This work focuses on a household (or door to door) waste collection problem in the Portuguese municipality of Seixal, which is modelled as a generalisation of a mixed capacitated arc routing problem (MCARP). The MCARP is known to be NP-hard. The proposed methodology uses: i) a GIS (geographic information system), for input/output and to reduce problem dimensions; ii) a matheuristic that iteratively solves a new hybrid model; and iii) two versions of a two-phase matheuristic. The latter pursues the generation of connected and compacted trips. During the first phase, called initial assignment, some links requiring service are assigned to vehicle services. In the second phase, the hybrid model finishes the assignment and generates a feasible set of trips. The quality of the generated solutions is assessed through the total time, as well as by some attractiveness measures. These measures evaluate the adequacy of the solutions for the real case-study, a crucial aspect for trips that need to be accepted by practitioners. With this purpose, a new attractiveness measure that introduces space dependent penalisation of overlaps, named weighted hull overlap, is also proposed. Computational results with 18 Seixal instances, with 265–1223 nodes and 492–2254 links, point to the good performance of the proposed.info:eu-repo/semantics/publishedVersio

    Effect of bio-functional MAO layers on the electrochemical behaviour of highly porous Ti

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    Ti foams are attractive for orthopaedic applications due to reduced Young's modulus and ability of bone ingrowth. However, poor corrosion behaviour and lack of bioactivity are yet to be overcome. In the present work, highly porous Ti samples were processed by powder metallurgy with space holder technique and bio-functionalized by micro-arc oxidation, resulting in nano/micro structured TiO2 surfaces containing bioactive elements. The electrochemical behaviour of these bio-functionalized highly porous Ti surfaces was evaluated through potentiodynamic polarization and EIS in physiological solution at body temperature. Results showed that bio-functionalization improved the corrosion behaviour of highly porous Ti. However, increased macro-porosity led to an increased corrosion rate.This work is supported by FCT with the reference project UID/EEA/04436/2019, M-ERA NET/0001/2015 project, and Programa de Accoes Universitarias Integradas Luso-Francesas' (PAUILF TC-12_14). CQE is financed by FCT under Pluriannual contract 2020-2023. The authors also gratefully acknowledge the "Investissements d'avenir" programs (nos. ANR-11-IDEX-0003-02 and ANR-10-EQPX-37 MATMECA Grant) for financial support on Micro-CT analysis

    Bibliotecas da Administração Central do Estado - Que futuros?

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    O presente relatório, centrado no estudo dos futuros, constitui uma análise crítica à situação atual das Bibliotecas da Administração Central do Estado (BACE). Este documento, que pretende contribuir para o debate sobre a sustentabilidade futura das BACE, reúne e sistematiza os resultados das duas fases de reflexão desenvolvidas (abril‐setembro 2015), conjugando diferentes métodos de análise e auscultação. É proposto um conjunto de recomendações assentes em três eixos estratégicos: • Eixo 1 – Gestão dos serviços de informação • Eixo 2 – Gestão dos recursos de informação • Eixo 3 – Gestão da transição bibliográfic

    Tradução e validação da Clinician Administered PTSD Scale (CAPS-CA-5) em crianças e adolescentes portugueses

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    Introduction: The aim of this study was to translate and validate into European Portuguese the CAPS-CA-5 (Clinician Administered PTSD Scale for Children and Adolescents), a semi-structured scale for the diagnosis of post-traumatic stress disorder in children and adolescents, according to the DSM-5 criteria. Material and Methods: This study was developed in three stages. In the first stage, the translation and back-translation of CAPS-CA-5 into European Portuguese was carried out. In the second stage, the version obtained in the previous step was subjected to a pre-test. In the third stage, the final version of CAPS-CA-5, the KIDCOPE questionnaires and the Depression, Anxiety and Stress Scale-Children were applied to 101 children who had experienced at least one potentially traumatic event. The children included in this study were between seven and 18 years old and had a follow-up period in a Child Psychiatry or Pediatrics Clinic in one of the three hospitals involved in this project of at least one month. Results: Regarding the confirmatory factor analysis, our results show that the CAPS-CA-5 is a suitable psychometric instrument to assess the diagnosis and symptoms severity of post-traumatic stress disorder according to DSM-5. Convergent validity was comparable to its original version. Although there were negative relationships with almost all of its clusters, these were not statistically significant when applied with the positive coping strategies of the KIDCOPE. The European Portuguese version of the CAPS-CA-5 showed a good internal consistency (Cronbach’s α for the total scale was 0.89). Conclusion: The European Portuguese version of CAPS-CA-5 has similar psychometric properties to its original versionIntrodução: O objetivo deste estudo foi traduzir e validar para português europeu a CAPS-CA-5 (Clinician Administered PTSD Scale for Children and Adolescents), uma escala semiestruturada para o diagnóstico de perturbação de stress pós-traumático em crianças e adolescentes, de acordo com os critérios do DSM-5. Material e Métodos: Este estudo foi desenvolvido em três etapas. Na primeira, foi realizada a tradução e contra-tradução da CAPS- -CA-5 para português europeu. Na segunda etapa, a versão obtida anteriormente foi submetida a um pré-teste. Na terceira etapa, a versão final da CAPS-CA-5, os questionários KIDCOPE e a Escala de Depressão, Ansiedade e Stresse - Crianças foram aplicados em 101 crianças que experienciaram pelo menos um evento potencialmente traumático. As crianças incluídas neste estudo tinham entre sete e 18 anos e tinham um período de acompanhamento em consulta de Psiquiatria Infantil ou Pediatria de pelo menos um mês, num dos três hospitais envolvidos neste projeto. Resultados: Em relação à análise fatorial confirmatória, os nossos resultados mostram que a CAPS-CA-5 é um instrumento psico-métrico adequado para avaliar o diagnóstico e a gravidade dos sintomas de perturbação de stresse pós-traumático de acordo com o DSM-5. A validade convergente foi comparável à versão original. Embora tenha havido relações negativas com quase todos os seus clusters, estas não foram estatisticamente significativas quando aplicadas com as estratégias de coping positivo do KIDCOPE. A versão em português europeu da CAPS-CA-5 apresentou boa consistência interna (α de Cronbach para a escala total foi de 0,89). Conclusão: A versão em português europeu do CAPS-CA-5 possui propriedades psicométricas semelhantes à sua versão originalinfo:eu-repo/semantics/publishedVersio

    Bibliotecas da Administração Central do Estado - Que futuro(s)?

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    Estudo realizado por solicitação do INA. Concluído e entregue em outubro de 2015.INA - Direção-Geral da Qualificação dos Trabalhadores em Funções Pública

    Fosfolipídios Retardam e Colesterol e seus Derivados Aceleram a Formação de Tumores Induzidos por Hidrocarbonetos Cancerígenos

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    Ficou experimentalmente comprovado que os fosfolipideos retardam e o colesterol e seus derivados aceleram a formação de tumores induzidos por hidrocarbonetos cancerígenos. Acentua-se a suma importância deste fenômeno, pois trata-se de dois grupos de lipídeos comuns, aliás componentes naturais de qualquer célula animal, capazes de influenciar, positivamente, o mecanismo da carcinogênese. O fato de que os fosfolipideos e o colesterol, ao lado das proteínas, constituem quantitativamente os componentes principais da membrana celular, conduziu ao raciocínio lógico que as membranas devem representar uma posição chave na etiologia do câncer

    A prediction rule to stratify mortality risk of patients with pulmonary tuberculosis

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    Tuberculosis imposes high human and economic tolls, including in Europe. This study was conducted to develop a severity assessment tool for stratifying mortality risk in pulmonary tuberculosis (PTB) patients. A derivation cohort of 681 PTB cases was retrospectively reviewed to generate a model based on multiple logistic regression analysis of prognostic variables with 6-month mortality as the outcome measure. A clinical scoring system was developed and tested against a validation cohort of 103 patients. Five risk features were selected for the prediction model: hypoxemic respiratory failure (OR 4.7, 95% CI 2.8-7.9), age >= 50 years (OR 2.9, 95% CI 1.7-4.8), bilateral lung involvement (OR 2.5, 95% CI 1.44.4), >= 1 significant comorbidity-HIV infection, diabetes mellitus, liver failure or cirrhosis, congestive heart failure and chronic respiratory disease-(OR 2.3, 95% CI 1.3-3.8), and hemoglobin = 6) mortality risk. The mortality associated with each group was 2.9%, 22.9% and 53.9%, respectively. The model performed equally well in the validation cohort. We provide a new, easy-to-use clinical scoring system to identify PTB patients with high-mortality risk in settings with good healthcare access, helping clinicians to decide which patients are in need of closer medical care during treatment.This work was supported by Fundacao Amelia de Mello/Jose de Mello Saude and Sociedade Portuguesa de Pneumologia (SPP). This work was developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). NSO is a FCT (Fundacao para a Ciencia e Tecnologia) investigator. MS is an Associate FCT Investigator. The fundershad no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    A Joint Search for Gravitational Wave Bursts with AURIGA and LIGO

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    The first simultaneous operation of the AURIGA detector and the LIGO observatory was an opportunity to explore real data, joint analysis methods between two very different types of gravitational wave detectors: resonant bars and interferometers. This paper describes a coincident gravitational wave burst search, where data from the LIGO interferometers are cross-correlated at the time of AURIGA candidate events to identify coherent transients. The analysis pipeline is tuned with two thresholds, on the signal-to-noise ratio of AURIGA candidate events and on the significance of the cross-correlation test in LIGO. The false alarm rate is estimated by introducing time shifts between data sets and the network detection efficiency is measured with simulated signals with power in the narrower AURIGA band. In the absence of a detection, we discuss how to set an upper limit on the rate of gravitational waves and to interpret it according to different source models. Due to the short amount of analyzed data and to the high rate of non-Gaussian transients in the detectors noise at the time, the relevance of this study is methodological: this was the first joint search for gravitational wave bursts among detectors with such different spectral sensitivity and the first opportunity for the resonant and interferometric communities to unify languages and techniques in the pursuit of their common goal.Comment: 18 pages, IOP, 12 EPS figure
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