A novel two-stage heart arrhythmia ensemble classifier

Atrial fibrillation (AF) and ventricular arrhythmia (Arr) are among the most common and fatal cardiac arrhythmias in the world. Electrocardiogram (ECG) data, collected as part of the UK Biobank, represents an opportunity for analysis and classification of these two diseases in the UK. The main objective of our study is to investigate a two-stage model for the classification of individuals with AF and Arr in the UK Biobank dataset. The current literature addresses heart arrhythmia classification very extensively. However, the data used by most researchers lack enough instances of these common diseases. Moreover, by proposing the two-stage model and separation of normal and abnormal cases, we have improved the performance of the classifiers in detection of each specific disease. Our approach consists of two stages of classification. In the first stage, features of the ECG input are classified into two main classes: normal and abnormal. At the second stage, the features of the ECG are further categorised as abnormal and further classified into two diseases of AF and Arr. A diverse set of ECG features such as the QRS duration, PR interval and RR interval, as well as covariates such as sex, BMI, age and other factors, are used in the modelling process. For both stages, we use the XGBoost Classifier algorithm. The healthy population present in the data, has been undersampled to tackle the class imbalance present in the data. This technique has been applied and evaluated using an ECG dataset from the UKBioBank ECG taken at rest repository. The main results of our paper are as follows: The classification performance for the proposed approach has been measured using F1 score, Sensitivity (Recall) and Specificity (Precision). The results of the proposed system are 87.22%, 88.55% and 85.95%, for average F1 Score, average sensitivity and average specificity, respectively. Contribution and significance: The performance level indicates that automatic detection of AF and Arr in participants present in the UK Biobank is more precise and efficient if done in a two-stage manner. Automatic detection and classification of AF and Arr individuals this way would mean early diagnosis and prevention of more serious consequences later in their lives

Shallow extra mixing in solar twins inferred from Be abundances

Lithium and beryllium are destroyed at different temperatures in stellar interiors. As such, their relative abundances offer excellent probes of the nature and extent of mixing processes within and below the convection zone. We determine Be abundances for a sample of eight solar twins for which Li abundances have previously been determined. The analyzed solar twins span a very wide range of age, 0.5-8.2 Gyr, which enables us to study secular evolution of Li and Be depletion. We gathered high-quality UVES/VLT spectra and obtained Be abundances by spectral synthesis of the Be II 313 nm doublet. The derived beryllium abundances exhibit no significant variation with age. The more fragile Li, however, exhibits a monotonically decreasing abundance with increasing age. Therefore, relatively shallow extra mixing below the convection zone is necessary to simultaneously account for the observed Li and Be behavior in the Sun and solar twins

Intervalo I: entre geografias e cinemas

O volume II desta obra encontra-se disponível em: http://hdl.handle.net/1822/38633O encontro entre geografia(s) e cinema(s) e a ideia de intervalo impuseram-se como título do livro que aqui se apresenta por reflectirem uma metodologia de trabalho de edição, uma estruturação conceptual e uma opção política. Os objectivos que persegui-mos, de criar intervalos, de abrir vãos, de estabele-cer um entre imagens e palavras, de extrair abis-mos e pontes entre cinemas e geografias permitem espaçar uma coisa da outra, fazer circular ventos e águas por ali, insistir no desmoronamento das vertentes, no deslizar do chão, no alargamento das passagens de matéria intensa. Com isto surgem ou-tras possibilidades de vivificar – libertar e expandir – a geografia, tanto no que respeita às relações com o cinema como nas relações que essa área de con-hecimento estabelece com as imagens para além do cinema, ou ainda nas relações que cria e inventa com o mundo, esse mundo oscilante e imprevisível no qual vivemos actualmente e que é constituído pelas imagens, através delas e com elas.En el encuentro entre geografía(s) y cinema(s) la idea de intervalo se impuso como título del libro que pre-sentamos porque refleja la metodología del trabajo de edición, su estructuración conceptual así como una opción política. Los objetivos que perseguimos, de abrir brechas, crear intervalos, establecerlos en-tre imágenes y palabras, extraer abismos y puentes entre cinemas y geografías, permiten espaciar una cosa de la otra, dejando circular vientos y aguas por allí, insistiendo en el derribo de las vertientes, los movimientos del suelo y ampliando los pasajes de materia intensa. Con ello, aparecen otras posibilida-des de revivir –liberar y expandir- la geografía, tan-to en sus relaciones con el cine como los que este área de conocimiento establece con las imágenes más allá del cinema, e incluso, en las relaciones que crea e inventa con el mundo, este mundo oscilan-te e imprevisible en el que vivimos actualmente, el cual también se constituye de imágenes, a través de ellas y con ellas.Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPqSocietat Econòmica Barcelonesa d’Amics del País-SEBAPRede Internacional de Pesquisa Imagens, Geografias e Educaçã

New perspectives into Gluconobacter-catalysed biotransformations

Different from other aerobic microorganisms that oxidise carbon sources to water and carbon dioxide, Gluconobacter catalyses the incomplete oxidation of various substrates with regio- and stereoselectivity. This ability, as well as its capacity to release the resulting products into the reaction media, place Gluconobacter as a privileged member of a non-model microorganism class that may boost industrial biotechnology. Knowledge of new technologies applied to Gluconobacter has been piling up in recent years. Advancements in its genetic modification, application of immobilisation tools and careful designs of the transformations, have improved productivities and stabilities of Gluconobacter strains or enabled new bioconversions for the production of valuable marketable chemicals. In this work, the latest advancements applied to Gluconobacter-catalysed biotransformations are summarised with a special focus on recent available tools to improve them. From genetic and metabolic engineering to bioreactor design, the most recent works on the topic are analysed in depth to provide a comprehensive resource not only for scientists and technologists working on/with Gluconobacter, but for the general biotechnologist

Replicate Periodic Windows in the Parameter Space of Driven Oscillators

In the bi-dimensional parameter space of driven oscillators, shrimp-shaped periodic windows are immersed in chaotic regions. For two of these oscillators, namely, Duffing and Josephson junction, we show that a weak harmonic perturbation replicates these periodic windows giving rise to parameter regions correspondent to periodic orbits. The new windows are composed of parameters whose periodic orbits have periodicity and pattern similar to stable and unstable periodic orbits already existent for the unperturbed oscillator. These features indicate that the reported replicate periodic windows are associated with chaos control of the considered oscillators

Using geographically weighted regression to explore the spatially heterogeneous spread of bovine tuberculosis in England and Wales

An understanding of the factors that affect the spread of endemic bovine tuberculosis (bTB) is critical for the development of measures to stop and reverse this spread. Analyses of spatial data need to account for the inherent spatial heterogeneity within the data, or else spatial autocorrelation can lead to an overestimate of the significance of variables. This study used three methods of analysis—least-squares linear regression with a spatial autocorrelation term, geographically weighted regression (GWR) and boosted regression tree (BRT) analysis—to identify the factors that influence the spread of endemic bTB at a local level in England and Wales. The linear regression and GWR methods demonstrated the importance of accounting for spatial differences in risk factors for bTB, and showed some consistency in the identification of certain factors related to flooding, disease history and the presence of multiple genotypes of bTB. This is the first attempt to explore the factors associated with the spread of endemic bTB in England and Wales using GWR. This technique improves on least-squares linear regression approaches by identifying regional differences in the factors associated with bTB spread. However, interpretation of these complex regional differences is difficult and the approach does not lend itself to predictive models which are likely to be of more value to policy makers. Methods such as BRT may be more suited to such a task. Here we have demonstrated that GWR and BRT can produce comparable outputs

Intervalo II: entre geografias e cinemas

O volume I desta obra encontra-se disponível em: http://hdl.handle.net/1822/35539[Excerto introdução] Apresentamos aos leitores o volume II do livro Intervalo: entre geografias e cinemas. Esta publicação trata-se a um só tempo da continuidade do volume I e da abertura para outras proposições, fazendo-se assim tanto um tomo adicional de um livro como um tomo único, independente do primeiro. Coloca-se, portanto, mais uma maneira de arriscar o intervalo como força na produção académica, como força de experimentação, como força de invenção de ideias e práticas, como força de intervenção entre evento geográfico e evento fílmico. Na introdução ao volume I apresentamos o âmbito mais vasto deste projecto editorial, pelo que aqui apenas retomamos alguns pontos. Insistimos em alguns aspectos e desdobramos outros para que os leitores possam avançar na leitura da obra sem a necessidade de voltar ao tomo anterior, ainda que seja nele onde estão explicitadas com mais intensidade e demora as nossas propostas e pretensões. Muito sumariamente, o objectivo de expandir o diálogo entre geografia e cinema e as variações que daí se vão desvelando tendo em conta as operações da imagem e das diferentes linguagens e modalidades de comunicação, os movimentos de permanência e impermanência que marcam as diferentes instâncias de produção de conhecimento, arte e tecnologia, bem como, o interpelar das fugas e deslizamentos que decorrem desse diálogo e que se vão constituindo como testemunhos de experiências múltiplas. (...)[Extracto introducción] Presentamos a los lectores el volumen II del libro Intervalo: entre geografías y cinemas. Esta publicación debe entenderse como la continuación del volumen I pero también como la apertura hacia otras proposiciones, siendo a la vez un tomo adicional de un libro y un tomo único, independiente del primero. Se trata, en definitiva, de reposicionar el intervalo como motor de producción académica, de experimentación, de creación de ideas y procedimientos, de intervención entre el evento geográfico y el fílmico. En la introducción del volumen I presentamos más ampliamente los propósitos de este proyecto editorial, con lo que aquí simplemente retomaremos algunos de ellos. Vamos a insistir en algunos y simplemente desdoblamos otros para que los lectores puedan avanzar en la lectura de la obra sin necesidad de volver al volumen anterior, pese a que sea allí donde se encuentran explicitadas con más amplitud nuestras propuestas y pretensiones. Sintéticamente: el objetivo es expandir el diálogo entre geografía y cine y también en las variaciones que emanan teniendo en cuenta los mecanismos de la imagen y de los diferentes lenguajes y modalidades de comunicación, los movimientos de permanencia e impermanencia que marcan las diferentes instancias de producción de conocimiento, arte y tecnología o bien como interpretación de las fugas y deslizamientos que se producen de este diálogo y que se constituyen como testimonios de experiencias múltiples. (...)Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPqSocietat Econòmica Barcelonesa d’Amics del País-SEBAPRede Internacional de Pesquisa Imagens, Geografias e Educaçã