12 research outputs found

    Convergent types for shared memory

    Get PDF
    Dissertação de mestrado em Computer ScienceIt is well-known that consistency in shared memory concurrent programming comes with the price of degrading performance and scalability. Some of the existing solutions to this problem end up with high-level complexity and are not programmer friendly. We present a simple and well-defined approach to obtain relevant results for shared memory environments through relaxing synchronization. For that, we will look into Mergeable Data Types, data structures analogous to Conflict-Free Replicated Data Types but designed to perform in shared memory. CRDTs were the first formal approach engaging a solid theoretical study about eventual consistency on distributed systems, answering the CAP Theorem problem and providing high-availability. With CRDTs, updates are unsynchronized, and replicas eventually converge to a correct common state. However, CRDTs are not designed to perform in shared memory. In large-scale distributed systems the merge cost is negligible when compared to network mediated synchronization. Therefore, we have migrated the concept by developing the already existent Mergeable Data Types through formally defining a programming model that we named Global-Local View. Furthermore, we have created a portfolio of MDTs and demonstrated that in the appropriated scenarios we can largely benefit from the model.É bem sabido que para garantir coerência em programas concorrentes num ambiente de memória partilhada sacrifica-se performance e escalabilidade. Alguns dos métodos existentes para garantirem resultados significativos introduzem uma elevada complexidade e não são práticos. O nosso objetivo é o de garantir uma abordagem simples e bem definida de alcançar resultados notáveis em ambientes de memória partilhada, quando comparados com os métodos existentes, relaxando a coerência. Para tal, vamos analisar o conceito de Mergeable Data Type, estruturas análogas aos Conflict-Free Replicated Data Types mas concebidas para memória partilhada. CRDTs foram a primeira abordagem a desenvolver um estudo formal sobre eventual consistency, respondendo ao problema descrito no CAP Theorem e garantindo elevada disponibilidade. Com CRDTs os updates não são síncronos e as réplicas convergem eventualmente para um estado correto e comum. No entanto, não foram concebidos para atuar em memória partilhada. Em sistemas distribuídos de larga escala o custo da operação de merge é negligenciável quando comparado com a sincronização global. Portanto, migramos o conceito desenvolvendo os já existentes Mergeable Data Type através da criação de uma formalização de um modelo de programação ao qual chamamos de Global-Local View. Além do mais, criamos um portfolio de MDTs e demonstramos que nos cenários apropriados podemos beneficiar largamente do modelo

    Boas práticas ao Serviço do Utente - Centro Hospitalar do Tâmega e Sousa, EPE

    No full text
    O CHTS pretende e ambiciona na literacia em saúde, na vertente do cidadão, que haja mais igualdades em saúde e que, este cidadão perante a necessidade de tomar decisões de forma autónoma (muitas vezes de elevada complexidade), sobre a promoção de saúde, prevenção das doenças ou seu tratamento, esteja informado e com conhecimentos para o fazer. Pretende que o cidadão seja capaz de obter melhor acesso aos cuidados de saúde, usar e usufruir da forma mais adequada e, de forma intencional e consciente, possa obter os maiores benefíciospara a manutenção do seu estado de saúde. A OMS, define Literacia em Saúde como “o grau em que os indivíduos têm a capacidade de obter, processar e entender as informações básicas de saúde para utilizarem os serviços e tomarem decisões adequadas de saúde”, ou seja, a literacia em saúde contempla um conjunto de conhecimentos, atitudes, habilidades e até competências que capacitam a pessoa no acesso, compreensão das informações para que possa avaliar de forma critica a sua relevância no uso responsável desse conhecimento. Foi, neste contexto, que surgiu no CHTS uma nova ótica de leitura e de intervenção das suas equipas multidisciplinares, na consecução de projetos e ações que visam reforçar os níveis de literacia, de forma multidimensional e colaborativa, aproximando-se cada vez mais da centralidade no cidadão, bem como de uma maior eficiência e eficácia dos serviços, qualidade assistencial e satisfação do cidadão e profissional. Deve-se muito à capacidade dos profissionais de saúde, mesmo com diferenças de uns para outros, em identificar as necessidades das pessoas, em estarem disponíveis para promover mudança, a avaliar diariamente o nível de compreensão, capacidades para realizar tarefas prescritas, motivação e nível de mudança comportamental do cidadão, tendo em conta a sua idade e o seu estado de saúde. José Ribeiro Nunes, Enf. Diretor, Prefácioinfo:eu-repo/semantics/publishedVersio

    The Political Uses of the Past During the Cold War: Conservative Intellectuals and the Military Dictatorship in Brazil

    No full text

    Characterisation of microbial attack on archaeological bone

    Get PDF
    As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

    NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

    No full text
    Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

    NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

    No full text
    Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data
    corecore