Time Series Cluster Kernel for Learning Similarities between Multivariate Time Series with Missing Data

Similarity-based approaches represent a promising direction for time series analysis. However, many such methods rely on parameter tuning, and some have shortcomings if the time series are multivariate (MTS), due to dependencies between attributes, or the time series contain missing data. In this paper, we address these challenges within the powerful context of kernel methods by proposing the robust \emph{time series cluster kernel} (TCK). The approach taken leverages the missing data handling properties of Gaussian mixture models (GMM) augmented with informative prior distributions. An ensemble learning approach is exploited to ensure robustness to parameters by combining the clustering results of many GMM to form the final kernel. We evaluate the TCK on synthetic and real data and compare to other state-of-the-art techniques. The experimental results demonstrate that the TCK is robust to parameter choices, provides competitive results for MTS without missing data and outstanding results for missing data.Comment: 23 pages, 6 figure

Fonds d'archives de la Cie Philippe Saire: guide pour la mise en place d'un processus de traitement

Le présent travail a été mandaté par Valérie Niederoest pour la Compagnie Philippe Saire qui est active dans le domaine de la danse contemporaine depuis sa fondation en 1986. Les diverses activités de la Compagnie ont engendré l’accumulation de nombreux documents de supports variés et divers ainsi que d’objets. En l’absence d’outils et de processus de gestion structurés, le repérage et l’accès aux documents n’est actuellement pas des plus aisés. Afin de remédier à cela, mes recherches visent à proposer des solutions qui permettront à la Compagnie d’organiser, contrôler, rechercher, repérer et accéder à ses archives de manière aisée afin qu’elle puisse les utiliser pour des projets particuliers ou pour des tâches quotidiennes. Mon étude se partage donc en trois axes : une revue de la littérature, une analyse de l’existant, la proposition d’un cadre de classification, ainsi qu’un guide proposant et expliquant comment et pourquoi appliquer les recommandations principales issues du domaine professionnel ou académique et adaptées au cas de la Compagnie. Ce guide est structuré selon les différentes activités archivistiques qui interviennent le long du cycle de vie du document : création, classification, tri et évaluation, conservation et préservation. Mes principales recommandations sont les suivantes : la validation et l’implémentation d’un cadre de classification, l’élaboration et l’application d’un calendrier de conservation, de règles de création et d’une politique de conservation, et pour finir la conservation et récolte de toute information et outil utile au contrôle du contenu du fonds

Classification of postoperative surgical site infections from blood measurements with missing data using recurrent neural networks

Clinical measurements that can be represented as time series constitute an important fraction of the electronic health records and are often both uncertain and incomplete. Recurrent neural networks are a special class of neural networks that are particularly suitable to process time series data but, in their original formulation, cannot explicitly deal with missing data. In this paper, we explore imputation strategies for handling missing values in classifiers based on recurrent neural network (RNN) and apply a recently proposed recurrent architecture, the Gated Recurrent Unit with Decay, specifically designed to handle missing data. We focus on the problem of detecting surgical site infection in patients by analyzing time series of their blood sample measurements and we compare the results obtained with different RNN-based classifiers

Oxidative Stress as a predictor of cardiovascular events in coronari artery disease patients

Abstract Background: Enhanced oxidative stress has been associated with atherosclerosis and coronary artery disease (CAD). However, the predictive value of circulating oxidative stress biomarkers for cardiovascular events (CE) in patients with CAD has remained poorly understood. Aim: To assess the prognostic significance of reactive oxygen metabolites, estimated as index of oxidative stress in serum samples by means of a commercial kit (ROMs, Diacron, Italy) on the rate of mortality and major adverse CE (MACE) in CAD. Methods: A study of 93 consecutive patients with angiographically documented CAD (75 males, age: 68?10 years, mean?SD) was made during a mean follow-up of 66 months until the occurrence of one of the following CE: cardiac and all cause death, non-fatal myocardial infarction and coronary revascularization [percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG)]. Patient data were retrospectively collected from the Institute\u27s electronic databank that saves demographic, clinical, instrumental and follow-up data of all patients admitted to our department. Results: The Kaplan-Meier survival estimates showed a significantly worst outcome in patients presenting elevated ROM level (>75th percentile, corresponding to 481 AU) (log rank=11, 7.5, 5.1; p<0.001, p<0.01, p<0.05 for cardiac and all cause death and MACEs, respectively). In a multivariate Cox regression model, elevated oxidative stress remained a significant predictor of cardiac and all cause death [hazard ratio (HR) 3.9, 95% confidence interval, 95% (CI) 1.4-11.1, p=0.01; HR=2.6, 95% CI 1.1-6.2, p=0.02) and MACE (HR=1.8, 95% CI 1.1-3.1, p=0.03)]. Conclusions: The estimation of ROMs may represent an additional prognostic tool in the assessment of CE in CAD patients

The hypoxic transcription factor KlMga2 mediates the response to oxidative stress and influences longevity in the yeast Kluyveromyces lactis

Hypoxia is defined as the decline of oxygen availability, depending on environmental supply and cellular consumption rate. The decrease in O2 results in reduction of available energy in facultative aerobes. The response and/or adaptation to hypoxia and other changing environmental conditions can influence the properties and functions of membranes by modifying lipid composition. In the yeast Kluyveromyces lactis, the KlMga2 gene is a hypoxic regulatory factor for lipid biosynthesis-fatty acids and sterols-and is also involved in glucose signaling, glucose catabolism and is generally important for cellular fitness. In this work we show that, in addition to the above defects, the absence of the KlMGA2 gene caused increased resistance to oxidative stress and extended lifespan of the yeast, associated with increased expression levels of catalase and SOD genes. We propose that KlMga2 might also act as a mediator of the oxidative stress response/adaptation, thus revealing connections among hypoxia, glucose signaling, fatty acid biosynthesis and ROS metabolism in K. lactis

Composite material comprising pectin and calcium phosphate and method for its realisation

A method for obtaining a composite material including an aqueous solution of pectin and a suspension/solution of calcium phosphate mixed together, wherein said solution of pectin cross-links with a portion of the calcium obtained from the solution of calcium phosphate and wherein a portion of the calcium phosphate in suspension remains as inorganic phase and composite materials obtained by this method

Mitochondrial Complex I: Structural and functional aspects

AbstractThis review examines two aspects of the structure and function of mitochondrial Complex I (NADH Coenzyme Q oxidoreductase) that have become matter of recent debate. The supramolecular organization of Complex I and its structural relation with the remainder of the respiratory chain are uncertain. Although the random diffusion model [C.R. Hackenbrock, B. Chazotte, S.S. Gupte, The random collision model and a critical assessment of diffusion and collision in mitochondrial electron transport, J. Bioenerg. Biomembranes 18 (1986) 331–368] has been widely accepted, recent evidence suggests the presence of supramolecular aggregates. In particular, evidence for a Complex I–Complex III supercomplex stems from both structural and kinetic studies. Electron transfer in the supercomplex may occur by electron channelling through bound Coenzyme Q in equilibrium with the pool in the membrane lipids. The amount and nature of the lipids modify the aggregation state and there is evidence that lipid peroxidation induces supercomplex disaggregation. Another important aspect in Complex I is its capacity to reduce oxygen with formation of superoxide anion. The site of escape of the single electron is debated and either FMN, iron–sulphur clusters, and ubisemiquinone have been suggested. The finding in our laboratory that two classes of hydrophobic inhibitors have opposite effects on superoxide production favours an iron–sulphur cluster (presumably N2) is the direct oxygen reductant. The implications in human pathology of better knowledge on these aspects of Complex I structure and function are briefly discussed

Sperimentazione di una tecnica naturale di decontaminazione di sedimenti marini di dragaggio per il riutilizzo come terreno agrario

The proposed technique is based on the use of natural plants (paspalum v., tamarix g.,spartium j.), and organic amendment, with the aim of reaching the following objectives: (1) sediment decontamination; (2) physical, chemical and biological amelioration of sediments. Good results were obtained in terms of adaptation of the plants used, decrease in contamination (about 20% for metals and 70% for hydrocarbons) and increase in nutrient content and microbial activity. Moreover, the proper monitoring of irrigation has permitted to reset the volume of leachate, ensuring, however, the field capacity and the decrease of salinity in the medium. The experiment was carried out at pilot-scale, treating 80 m3 of sediment with AGRIPORT technology

Detection and genotyping of human Papillomavirus in urine samples from unvaccinated male and female adolescents in Italy

The introduction of vaccination against Human Papillomavirus (HPV) in adolescent girls in 2006 has focused virological surveillance on this age group. As few studies have evaluated HPV infections in young populations, further data are needed in order to improve and extend prophylactic policy and to monitor epidemiological changes. The present study aimed at evaluating overall and type-specific HPV prevalence in both female and male adolescents in Italy. HPV DNA detection and genotyping was performed on urine samples collected from 870 unvaccinated adolescents (369 females, 501 males, 11-18 years of age) in five cities in Italy. Following DNA extraction by means of a commercial kit (NucliSENS®-miniMAG®, bioMérieux), the L1 gene fragment was PCR amplified and genotyped by restriction fragment length polymorphism analysis. HPV DNA was detected in 1.5% of all samples, and in 3% and 0.4% of samples from females and males, respectively. In approximately 70% of HPV DNA positive adolescents, the infection was due to a single genotype, with 88.9% of genotypes belonging to the HR-clade. The only two HPV-positive boys (14 and 18 years old) had HPV-70 genotype. Only one of the 11 HPV-infected girls was in the 11-14 age-group. HPV prevalence was 4.2% in girls aged 15-18 years and 60% of infections were due to vaccine types HPV-16 or HPV-6/-11. This is one of the few studies, the first conducted in Italy, on HPV infection in adolescents. Urine testing is the easier way of detecting HPV infection in younger populations. Our data revealed a very low HPV prevalence, and no infections were observed in the 12-year-old vaccine target population. The majority of infections were seen in females aged 15-18 years. Overall, more than 50% and 30% of the potentially persistent HPV infections detected in this group could have been prevented by the quadrivalent and the bivalent vaccines, respectively

Identificazione e caratterizzazione genotipica e fenotipica dei soggetti a rischio di diabete

Introduzione. La prevalenza del diabete mellito tipo 2 (DM2) è in aumento in tutto il mondo. L’individuazione di strumenti migliori per lo screening del DM2 e per l’identificazione dei soggetti ad elevato rischio può favorire un intervento mirato più efficace ed economicamente vantaggioso. Obiettivo dello studio. Lo studio GENFIEV (GENetica, FIsiopatologia ed Evoluzione del diabete tipo 2) si propone di identificare le caratteristiche genotipiche e fenotipiche dei soggetti che sviluppano DM2. Pazienti e metodi. A tal fine 1017 soggetti (589 donne e 428 uomini), indirizzati dal medico di medicina generale al Centro Diabetologico perché ad alto rischio di diabete (screening opportunistico) sono stati sottoposti a questionario FINDRISC, visita medica, esami ematochimici di routine ed OGTT con misurazioni multiple di glicemia, insulinemia e c-peptide per la valutazione della secrezione e della sensibilità insulinica. Sono stati, inoltre, valutai i seguenti polimorfismi rs7903146 di TCF7L2 e rs1111875 di HHEX/IDE. Risultati. Gli algoritmi di rischio basati su criteri clinici (come il questionario FINDRISC) rappresentano uno strumento efficace per la predizione del DM2. Tale capacità predittiva può essere migliorata con l’uso di biomarcatori di rischio non tradizionali. Il deficit di secrezione insulinica rappresenta l’alterazione metabolica caratteristica della condizione di disglicemia. Nell’ambito dei soggetti ad alto rischio di DM2 ma con normale regolazione glicemica è possibile identificare un deficit della funzione β-cellulare correlato a valori glicemici più elevati già nelle fasi precoci del carico orale di glucosio (1 ora). Nella popolazione italiana il TCF7L2, uno dei geni di rischio candidati, risulta altamente prevalente fra i soggetti con alterazioni della regolazione glucidica e si associa al difetto della funzione β-cellulare. Gli effetti epistatici di altri geni possono potenziare le azioni del TCF7L2 a livello β-cellulare. L’identificazione di soggetti a rischio di DM2 può contribuire a ridurre l’impatto di tale condizione sul rischio cardiovascolare. Conclusioni. La caratterizzazione clinica e fisiopatologica dei soggetti a rischio di DM2 può contribuire ad identificare gruppi di individui a rischio più elevato ai quali indirizzare maggiori risorse per la prevenzione della malattia