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

Release of Polycyclic Aromatic Hydrocarbons and Heavy Metals from Rubber Crumb in Synthetic Turf Fields: Preliminary Hazard Assessment for Athletes

Synthetic turf, made with an infill of rubber crumb from used tyres or virgin rubber, is now common in many sporting facilities. It is known that it contains compounds such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals. We evaluated in nine samples of rubber crumb the total content of some heavy metals (Zn, Cd, Pb, Cu, Cr, Ni, Fe) normally found in tyres by microwave mineralization and the levels of the 14 US EPA priority PAHs by Soxhlet extraction and HPLC analysis. The results showed high levels of PAHs and zinc in all rubber crumb samples compared to rubber granulate limits set by Italian National Amateur League (LND). Following the precautionary principle, a risk assessment at 25°C was done, using the Average Daily Dose (ADD) assumed by athletes, expressed in terms of mass of contaminant per unit of body weight per day (mg/kg day), and the Lifetime Average Daily Dose (LADD) and then evaluating the Hazard Index (HI) and the Cumulative Excess Cancer Risk (∑ECR). In the different rubber granulates samples the HI ranges from a minimum of 8.94×10-7 to a maximum of 1.16×10-6, while the ∑ECR ranges from a minimum of 4.91×10-9 to a maximum of 1.10×10-8. Finally, the aim of this study was to estimate the “hazard” for athletes inhaling PAHs released at the high temperatures this synthetic turf may reach. Then a sequence of proofs was carried out at 60°C, a temperature that this rubber crumb can easily reach in sporting installations, to see whether PAH release occurs. The toxicity equivalent (TEQ) of eva

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

Insulin degludec/insulin aspart combination for the treatment of type 1 and type 2 diabetes

Glycemic control remains the major therapeutic objective to prevent or delay the onset and progression of complications related to diabetes mellitus. Insulin therapy represents a cornerstone in the treatment of diabetes and has been used widely for achieving glycemic goals. Nevertheless, a large portion of the population with diabetes does not meet the internationally agreed glycemic targets. Moreover, insulin treatment, especially if intensive, may be associated with emergency room visits and hospitalization due to hypoglycemic events. Therefore, fear of hypoglycemia or hypoglycemic events represents the main barriers to the attainment of glycemic targets. The burden associated with multiple daily injections also remains a significant obstacle to initiating and maintaining insulin therapy. The most attractive insulin treatment approach should meet the patients' preference, rather than demanding patients to change or adapt their lifestyle. Insulin degludec/insulin aspart (IDegAsp) is a new combination, formulated with ultra-long-acting insulin degludec and rapid-acting insulin aspart, with peculiar pharmacological features, clinical efficacy, safety, and tolerability. IDegAsp provides similar, noninferior glycemic control to a standard basal-bolus regimen in patients with type 1 diabetes mellitus, with additional benefits of significantly lower episodes of hypoglycemia (particularly nocturnal) and fewer daily insulin injections. Moreover, although treatment strategy and patients' viewpoint are different in type 1 and type 2 diabetes, trial results suggest that IDegAsp may be an appropriate and reasonable option for initiating insulin therapy in patients with type 2 diabetes inadequately controlled on maximal doses of conventional oral agents. This paper will discuss the role of IDegAsp combination as a novel treatment option in diabetic patients. © 2014 Dardano et al

Comparison of Three Dietary Assessment Methods to Estimate Meat Intake as Part of a Meat Reduction Intervention among Adults in the UK

Food diaries are used to estimate meat intake at an individual level but it is unclear whether simpler methods would provide similar results. This study assessed the agreement between 7 day food diaries in which composite dishes were disaggregated to assess meat content (reference method), and two simpler methods: (1) frequency meal counts from 7 day food diaries; and (2) 7 day dietary recalls, each using standard estimated portion sizes. We compared data from a randomized controlled trial testing a meat reduction intervention. We used Bland-Altman plots to assess the level of agreement between methods at baseline and linear mixed-effects models to compare estimates of intervention effectiveness. At baseline, participants consumed 132 g/d (±75) of total meat; frequency meal counts and dietary recalls underestimated this by an average of 30 and 34 g/day, respectively. This was partially explained by an underestimation of the assumed portion size. The two simpler methods also underestimated the effect of the intervention, relative to control, though the significant effect of the intervention was unchanged. Simpler methods underestimated absolute meat intake but may be suitable for use in studies to measure the change in meat intake in individuals over time