The diversity-accuracy duality in ensembles of classifiersd

Horizontal scaling of Machine Learning algorithms has the potential to tackle concerns over the scalability and sustainability of Deep Learning methods, viz. their consumption of energy and computational resources, as well their increasing inaccessibility to researchers. One way to enact horizontal scaling is by employing ensemble learning methods, since they enable distribution. There is a consensus on the point that diversity between individual learners leads to better performance, which is why we have focused on it as the criterion for distributing the base models of an ensemble. However, there is no standard agreement on how diversity should be defined and thus how to exploit it to construct a high-performing classifier. Therefore, we have proposed different definitions of diversity and innovative algorithms which promote it in a systematic way. We have first considered architectural diversity with an algorithm called WILDA: Wide Learning of Diverse Architectures. In a distributed fashion, this algorithm evolves a set of neural networks that are pretrained on the target task and diverse w.r.t. architectural feature descriptors. We have then generalised this notion by defining behavioural diversity on the basis of the divergence between the errors made by different models on a dataset. We have defined several diversity metrics and used them to guide a novelty search algorithm which builds an ensemble of behaviourally diverse classifiers. The algorithm promotes diversity in ensembles by explicitly searching for it, without selecting for accuracy. We have then extended this approach with a surrogate diversity model, which reduces the computational burden of this search by eliminating the need to train each network in the population with stochastic gradient descent at each step. These methods have enabled us to investigate the role that both architectural and behavioural diversity play in contributing to the performance of an ensemble. In order to study the relationship between diversity and accuracy in classifier ensembles, we have then proposed several methods that extend the novelty search with accuracy objectives. Surprisingly, we have observed that, with the highest-performing diversity metrics, there is an equivalence between searching for diversity objectives and searching for accuracy objectives. This contradicts widespread assumptions that a trade-off must be found by balancing diversity and accuracy objectives. We therefore posit the existence of a diversity-accuracy duality in ensembles of classifiers. An implication of this is the possibility of evolving diverse ensembles without detriment to their accuracy, since it is implicitly ensured.Open Acces

Validation of the portuguese version of the attitudes to evidence-based practice questionnaire: an exploratory approach

Background: The lack of cultural and linguistically sensitive instruments prevents the opportunity of assessing attitudes and barriers of health care staff towards evidence-based practice. The aim of this communication is to report the validation process in the Portuguese context of the Attitudes to Evidence Based Practice Questionnaire. Methods: We developed a cross-sectional, descriptive psychometric validation study. For cultural adaptation, a bidirectional translation was carried out, accordingly to common standards. To determine the psychometric properties of the questionnaire we conducted a Principal Component Analysis with Varimax orthogonal rotation. The reliability of the questionnaire was assessed by Cronbach's alpha. Results: We obtained 244 valid questionnaires with a 64.2% response rate. Data collected explained that the questionnaire showed an acceptable internal consistency (a = .63). Subjected the questionnaire to a principal components analysis using Varimax method, we obtained eight dimensions that explain 56.66% of total variance. Conclusions: The exploratory factorial analysis conducted demonstrated valid empiric evidence and the questionnaire could be used in our context

Actitudes y barreras para la práctica de enfermería basada en la evidencia en un contexto comunitario

Trabalho de Investigação desenvolvido no âmbito da atribuição da Bolsa de Investigação Enfermeira Maria Aurora Bessa pela Secção Regional do Norte da Ordem dos Enfermeiros em 2010Enquadramento: Várias pesquisas, têm identificado barreiras à prática baseada em evidência (PBE). A maioria dessas investigações foi realizada em contextos diferenciados. Justifica-se o desenvolvimento de investigação para identificar barreiras e atitudes face à PBE em contexto comunitário, atendendo à reorganização e centralidade dos Cuidados de Saúde Primários. Os objetivos de pesquisa foram: a) identificar barreiras percecionadas face à adoção de uma prática de enfermagem baseada na evidência em contexto comunitário; b) descrever as atitudes dos enfermeiros em relação à prática baseada em evidência. Metodologia: Desenvolveu-se um estudo transversal, exploratório e descritivo que decorreu numa Unidade Local de Saúde do norte de Portugal, recorrendo à versão teste do “Questionário de Atitudes face à Prática Baseada em Evidência” (Mckenna, Ashton e Keeney, 2004). Os resultados sobrepõem-se aos dos estudos internacionais embora considerem especificidades nacionais. No geral, as barreiras identificadas são de várias etiologias: pessoal, organizacional, cultural e científica. Em conclusão, uma PBE vai ao encontro da obrigação social da enfermagem, alicerça a sua credibilidade entre as ciências da saúde e sustenta eventuais mudanças ao nível político. É fundamental identificar, barreiras e atitudes, independentemente das suas origens de modo a estruturar estratégias de intervenção futuras.Background: Several studies have identified barriers to evidence-based practice (EBP). Most of these investigations were carried out in different contexts. Therefore it is justified the development of research to identify barriers and attitudes to EBP in a community context, given the centrality of the reorganization and Primary Health Care. The research objectives were: a) identify barriers perceived considering the adoption of an evidence-based nursing practice in a community setting; b) describe the nurse’s attitudes related to evidence-based practice. Methodology: We developed a cross-sectional study, exploratory and descriptive which took place in Local Health Unit in northern Portugal, using the test version of the "Questionnaire Attitudes to Evidence Based Practice" (McKenna, Ashton and Keeney, 2004). The results overlaid with those of international studies but consider national specificities. Overall, the barriers identified have various etiologies: personal, organizational, cultural and scientific. In conclusion, a PBE meets the social obligation of nursing, reinforcing his credibility among the health sciences and supports changes at the political level. It is important to identify barriers and attitudes, regardless their origins in order to structure future intervention strategies.Encuadramiento: Varios estudios han identificado las barreras para la práctica basada en la evidencia (PBE). La mayoría de estas investigaciones se llevó a cabo en diferentes contextos. Se justifica el desarrollo de la investigación para identificar las barreras y actitudes de PBE en un contexto comunitario, dada la importancia de la reorganización y la Atención Primaria de Salud. Los objetivos de la investigación fueron los siguientes: a) identificar las barreras percecionadas contra de la adopción de una práctica de enfermería basada en la evidencia en un contexto comunitario, b) describir las actitudes de las enfermeras en relación con la práctica basada en la evidencia. Metodología: Se desarrolló un estudio transversal, exploratorio y descriptivo que tuvo lugar en una Unidad Local de Salud en el norte de Portugal, con la versión de test del "Cuestionario de Actitudes Práctica Basada en Evidencias" (McKenna, Ashton y Keeney, 2004). Los resultados coinciden con los de estudios internacionales, pero teniendo en cuenta las circunstancias nacionales. En general, las barreras identificadas son de diversas etiologías: personal, organizacional, cultural y científico. En conclusión, una PBE cumple con la obligación social de la enfermería, fundó su credibilidad entre las ciencias de la salud y es compatible con cualquier cambio en el nivel político. Es importante identificar las barreras y actitudes, independientemente de sus orígenes con el fin de estructurar futuras estrategias de intervención.Secção Regional do Norte da Ordem dos Enfermeiro

Atitudes e barreiras à prática de enfermagem baseada na evidência em contexto comunitário

Introdução: Várias pesquisas têm identificado diferentes atitudes e barreiras à prática baseada em evidência (PBE), nomeadamente em contextos diferenciados. Embora muitos dos resultados destes estudos possam ser transpostos para os cuidados de saúde primários (CSP), a realidade é que a importância especial e crescente da PBE, justifica o desenvolvimento de investigação destinada a precisar um diagnóstico de situação às atuais barreiras e atitudes face à PBE em CSP, especialmente considerando a reorganização e centralidade destes no Serviço de Saúde Português. Objetivos: Os objetivos de pesquisa foram: a) identificar barreiras percecionadas face à adoção de uma prática de enfermagem baseada na evidência em contexto comunitário; b) descrever as atitudes dos enfermeiros em relação à prática baseada em evidência. Para a sua consecução, procedeu-se à ordenação das atitudes e barreiras face à PBE identificadas, com base na pontuação agregada, considerando apenas as médias que totalizavam scores superiores a 50% (15 em 26 itens). Metodologia: Desenvolveu-se um estudo transversal, exploratório e descritivo que decorreu numa Unidade Local de Saúde (ULS) do norte de Portugal, recorrendo à versão teste do “Questionário de Atitudes face à Prática Baseada em Evidência” (Mckenna, Ashton e Keeney, 2004) e ainda à caraterização de diversas variáveis sociodemográficas. Foram incluídos todos os enfermeiros (N=129) a trabalhar em contexto comunitário: Unidades de Saúde Familiar, Unidades de Cuidados de Saúde Personalizados, Unidades de Cuidados na Comunidade e Unidade de Saúde Pública. A colheita de dados decorreu entre dezembro de 2010 e março de 2011. Resultados: A amostra (n=95), é maioritariamente constituída por mulheres, sendo a faixa etária mais representativa dos 21-30 anos. São detentores de especialização em enfermagem 43,16% (n=41), tendo 28,4% (n=27) participado em trabalhos de investigação. Quanto às principais fontes de informação/conhecimento utilizadas para apoio às práticas, destacam-se os protocolos e os cursos, em detrimento do acesso a revistas científicas. Complementarmente foi quantificada a percentagem estimada pelos inquiridos, segundo os quais, a sua prática clínica diária é baseada em evidências: 62,6% (n=82). Em relação às barreiras identificadas, os resultados obtidos sobrepõem-se aos dos estudos internacionais embora considerem especificidades nacionais. No geral, as barreiras identificadas são de várias etiologias: pessoal, organizacional, cultural e científica, embora com predomínio da dimensão pessoal. No que se refere às atitudes é de destacar o elevado interesse e convicção demonstrados em assumir que uma PBE conduziria à adoção das melhores práticas clínicas e consequentemente a cuidados de maior qualidade, associando esta dimensão a um maior desenvolvimento profissional. Conclusões: A prática de enfermagem baseada em evidência vai ao encontro da obrigação social da enfermagem, alicerça a sua credibilidade entre as ciências da saúde e sustenta eventuais mudanças ao nível político. É portanto fundamental identificar barreiras e atitudes, independentemente das suas origens, de modo a estruturar estratégias de intervenção futuras. No nosso estudo, os enfermeiros demonstram acreditar na importância da prática baseada em evidência para o futuro da profissão, tendo uma atitude positiva face à mesma. Contudo, assumem que sentir-se-iam mais seguros se discutissem os resultados de investigação com alguém mais experiente ou se detivessem formação adequada nesta área

Validation of the Portuguese version of the attitudes and barriers to evidence-based practice questionnaire

1. Objective: Several studies have demonstrated a wide range of attitudes and barriers towards the evidence-based practice from health professionals in general and nurses in particular. This communication aims to describe the process of linguistic and cultural validation to the Portuguese language of the Attitudes and Barriers Questionnaire to Evidence Based Practice (QABPBE). Its availability should provide an additional tool that can contribute to a better assessment of attitudes and perceived barriers related to evidence-based practice. 2. Methods: The QABPBE is an instrument whose objective is to assess the attitudes and barriers with which nurses are faced regarding evidence based practice (EBP) and includes 26 items measured on an ordinal Likert scale ranging from 1 ( strongly disagree) to 5 ( strongly agree ). We decided to proceed with its translation and adaptation to our context, studying the psychometric properties of the Portuguese version by developing a cross-sectional study. For cultural adaptation we performed a bidirectional translation according to the usual standards. To examine the construct validity, we used the Principal Component Analysis with a Varimax orthogonal rotation. For the selection of factors we follow the criterion: eingvalues specific > 1 and excluding loads below 0.30 factor. The reliability of the questionnaire was assessed using the Cronbach’s alpha. 3 Results: Participated 244 nurses providing care in different contexts in a local health unit in northern Portugal corresponding to a response rate of 64.2 %. The majority of subjects were women (85.8%) aged 31 and 40 years (45.7%) followed by 21 to 30 years (32.4%) and 41 to 50 (17.4%). Of the participants, 80.7 % completed a graduate program (licensure degree) in nursing education with a duration of four academic year’s full time. In terms of postgraduate qualification (Masters and/or PhD), 12.3% already obtain it and 15 % found himself presently attending it. Approximately 48.4 % had a specialist professional title in nursing. We also observed that only 26.3 % of nurses had been involved with variable and heterogeneous statutes in several research projects. The version we study has 26 items and presents an acceptable internal consistency (α = 0.60). The principal components analysis suggests eight dimensions that explain 55.7 % of the total variance. 4 Discussion: Analysis demonstrated empirical evidence that the questionnaire is valid for use in the studied context and therefore may contribute to its implementation and dissemination among nurses. The assessment of attitudes and barriers should be a first step and a structural support for the definition of personalized and directed interventions to specific contexts, to promote evidence-based practice among health professionals

Validación de la versión portuguesa del Cuestionario de Eficacia Clínica y Práctica Basada en Evidencias

OBJETIVOS: descrever o processo de tradução e validação linguística e cultural para o contexto português do Questionário de Eficácia Clínica e Prática Baseada em Evidências (QECPBE). MÉTODO: desenvolveu-se um estudo metodológico e transversal. Foi efetuada tradução e retroversão, de acordo com os padrões usuais. Na determinação das características psicométricas do QECPBE utilizou-se a Análise de Componentes Principais com rotação ortogonal, segundo o método Varimax, seguida de análise fatorial confirmatória. A consistência interna foi determinada pelo valor alfa de Cronbach. A coleta de dados ocorreu entre dezembro de 2013 e fevereiro de 2014. RESULTADOS: participaram 358 enfermeiros que exercem a prática clínica num centro hospitalar do norte de Portugal. O QECPBE apresenta 20 itens e três subescalas: Práticas (α=0,74); Atitudes (α=0,75); Conhecimentos/Habilidades e Competências (α=0,95), apresentando consistência interna global de α=0,74. No modelo testado obteve-se variância explicada de 55,86%. O modelo demonstrou um bom ajuste: χ2(167)=520,009; p=0,0001; χ2df=3,114; CFI=0,908; GFI=0,865; PCFI=0,798; PGFI=0,678; RMSEA=0,077 (IC90%=0,07-0,08). CONCLUSÃO: através da análise fatorial confirmatória realizada demonstrou-se que o questionário é válido e adequado para utilização no contexto estudado.OBJETIVOS: describir el proceso de traducción y validación lingüística y cultural para el contexto portugués del Cuestionario de Eficacia Clínica y Práctica Basada en Evidencias (CECPBE). MÉTODO: se desarrolló un estudio metodológico y transversal. Fue efectuada traducción y retroversión de acuerdo con los estándares usuales. En la determinación de las características psicométricas del CECPBE se utilizó el Análisis de Componentes Principales con rotación ortogonal, según el método Varimax, seguido por análisis factorial confirmatorio. La consistencia interna fue determinada por el valor alfa de Cronbach. La recolección de datos ocurrió entre diciembre de 2013 y febrero de 2014. RESULTADOS: participaron 358 enfermeros que ejercían la práctica clínica en un centro hospitalario en el norte de Portugal. El CECPBE presenta 20 ítems y tres subescalas: Prácticas (α=0,74); Actitudes (α=0,75); Conocimientos/Habilidades y Competencias (α=0,95), presentando consistencia interna global de α=0,74. En el modelo probado se obtuvo variancia explicada de 55,86%. El modelo demostró un buen ajuste: χ2(167)=520,009; p=0,0001; χ2df=3,114; CFI=0,908; GFI=0,865; PCFI=0,798; PGFI = 0,678; RMSEA = 0,077 (IC90%=0,07-0,08). CONCLUSIÓN: a través del análisis factorial confirmatorio se demostró que el cuestionario es válido y adecuado para utilización en el contexto estudiado.OBJECTIVES: to describe the process of translation and linguistic and cultural validation of the Evidence Based Practice Questionnaire for the Portuguese context: Questionário de Eficácia Clínica e Prática Baseada em Evidências (QECPBE). METHOD: a methodological and cross-sectional study was developed. The translation and back translation was performed according to traditional standards. Principal Components Analysis with orthogonal rotation according to the Varimax method was used to verify the QECPBE's psychometric characteristics, followed by confirmatory factor analysis. Internal consistency was determined by Cronbach's alpha. Data were collected between December 2013 and February 2014. RESULTS: 358 nurses delivering care in a hospital facility in North of Portugal participated in the study. QECPBE contains 20 items and three subscales: Practice (α=0.74); Attitudes (α=0.75); Knowledge/Skills and Competencies (α=0.95), presenting an overall internal consistency of α=0.74. The tested model explained 55.86% of the variance and presented good fit: χ2(167)=520.009; p = 0.0001; χ2df=3.114; CFI=0.908; GFI=0.865; PCFI=0.798; PGFI=0.678; RMSEA=0.077 (CI90%=0.07-0.08). CONCLUSION: confirmatory factor analysis revealed the questionnaire is valid and appropriate to be used in the studied context

Portuguese propolis: a source of valuable bioactivities

To FEDER/COMPETE/POCI– Operational Competitiveness and Internationalization Programme, under Project POCI-01-0145-FEDER-006958 and FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks