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Classification of sequential data (data obtained from series of actions in chronological order) has many applications in security, marketing or ergonomy. In this paper, we present a tool for classification of sequential data. We introduce a new clean dataset of web-browsing logs, and study the case of implicit authentification from web-browsing. We then detail more of the functioning of the tool and some of its parameters.dblp:conf/ecai/KahnLR16 fatcat:xzowfbasrnhyljkscptidyhaoy
Faced with both identity theft and the theft of means of authentication, users of digital services are starting to look rather suspiciously at online systems. To increase access security it is necessary to introduce some new factor of implicit authentication such as user behavior analysis. A behavior is made up of a series of observable actions and taken as a whole, the most frequent of these actions amount to habit. The challenge is to detect identity theft as quickly as possible and,doi:10.1016/j.dam.2018.11.016 fatcat:khs6i2o3irdbbauyd5eezdwyau
more »... lly, to validate a legitimate identity for as long as possible. To take up this challenge, we introduce in this paper a closed set-based learning classifier. This classifier is inspired by classification in concept lattices from positive and negative examples and several works on emerging patterns. We also rely on the tf-idf parameter used in the context of information retrieval. We propose three heuristics named H c tf −idf , H c sup and H c supM in to select closed patterns for each class to be described. To compute performance of our models we have followed an experimental protocol described in a previous study which had the same purpose. Then, we compared the results from our own dataset of web navigation connection logs of 3, 000 users over a six-month period with the heuristic H sup introduced in this study. Moreover, to strengthen our analysis, we have designed and set up one model based on the naive Bayes classifier to be used as a reference statistical tool.
Lecture Notes in Computer Science
Classical information retrieval methods often lose valuable information when aggregating weights, which may diminish the discriminating power between documents. To cope with this problem, the paper presents an approach for ranking documents in IR, based on a vectorbased ordering technique already considered in fuzzy logic for multicriteria analysis purpose. Moreover, the proposed approach uses a possibilistic framework for evaluating queries to a document collection, which distinguishes betweendoi:10.1007/11670834_4 fatcat:mp5ivid6wjf3fo2nvhf2ic7eyq
more »... descriptors that are certainly relevant and those which are possibly relevant only. The proposal is evaluated on a standard collection that allows to compare the effectiveness of this approach with a classical one. The proposed method provides an improvement of the precision of the Mercure IR system.
Faced with both identity theft and the theft of means of authentication, users of digital services are starting to look rather suspiciously at online systems. The behavior is made up of a series of observable actions of an Internet user and, taken as a whole, the most frequent of these actions amount to habit. Habit and reputation oer ways of recognizing the user. The introduction of an implicit means of authentication based upon the user's behavior allows web sites and businesses todblp:conf/cla/CoupelonDLLR14 fatcat:f2wczfumurfuli42uuhthngrxq
more »... the risks they take when authorizing access to critical functionalities. In this paper, we propose a new model for implicit authentication of web users based on extraction of closed patterns. On a data set of web navigation connection logs of 3,000 users over a six-month period we follow the experimental protocol described in  to compute performance of our model.
Classical information retrieval (IR) methods often lose valuable information when aggregating weights, which may diminish the discriminating power between documents. To cope with this problem, the paper presents an approach for ranking documents in IR, based on a vector-based ordering technique already considered in fuzzy logic for multiple criteria analysis purpose. Moreover, the proposed approach uses a possibilistic framework for encoding the retrieval status values. The approach, applied todblp:conf/eusflat/BoughanemLP05 fatcat:uc6izdh54fgkxc2mhvqapu4loi
more »... a benchmark collection, has been shown to improve IR precision w.r.t. classical approaches.
Bacteria are able to de-epoxidize or epimerize deoxynivalenol (DON), a mycotoxin, to deepoxydeoxynivalenol (deepoxy-DON or DOM-1) or 3-epi-deoxynivalenol (3-epi-DON), respectively. Using different approaches, the intestinal toxicity of 3 molecules was compared and the molecular basis for the reduced toxicity investigated. In human intestinal epithelial cells, deepoxy-DON and 3-epi-DON were not cytotoxic, did not change the oxygen consumption or impair the barrier function. In intestinaldoi:10.1038/srep29105 pmid:27381510 pmcid:PMC4933977 fatcat:xmca7sqpinbkjji6hbjude3pfe
more »... , exposure for 4 hours to 10 μM DON induced intestinal lesions not seen in explants treated with deepoxy-DON and 3-epi-DON. A pan-genomic transcriptomic analysis was performed on intestinal explants. 747 probes, representing 323 genes, were differentially expressed, between DON-treated and control explants. By contrast, no differentially expressed genes were observed between control, deepoxy-DON and 3-epi-DON treated explants. Both DON and its biotransformation products were able to fit into the pockets of the A-site of the ribosome peptidyl transferase center. DON forms three hydrogen bonds with the A site and activates MAPKinases (mitogen-activated protein kinases). By contrast deepoxy-DON and 3-epi-DON only form two hydrogen bonds and do not activate MAPKinases. Our data demonstrate that bacterial de-epoxidation or epimerization of DON altered their interaction with the ribosome, leading to an absence of MAPKinase activation and a reduced toxicity. Mycotoxins are toxic secondary metabolites produced by various molds, such as Aspergillus, Penicillium and Fusarium which may contaminate food and feed at all stages of the food/feed chain 1,2 . Despite the improvement of agricultural and manufacturing practices, mycotoxin contamination cannot be avoided and still represents a permanent health risk for both humans and animals. It is thus important to develop decontamination strategies 3 . Among mycotoxins, deoxynivalenol (DON) produced by Fusarium species, is commonly detected in cereal crops, including wheat, barley, and maize. It is the most abundant trichothecene in food with a frequent occurrence at toxicologically relevant concentrations worldwide 4,5 . DON causes acute and chronic disorders in humans and animals, with the gastrointestinal tract being an organ sensitive to its adverse effects 6 . DON affects the intestinal histomorphology, impairs barrier function and nutrient absorption 7,8 . DON also disrupts the local intestinal immune response; it triggers and potentiates intestinal inflammation 9,10 . At the cellular and subcellular level, DON binds to the ribosome, inhibits protein and nucleic acid synthesis and triggers ribotoxic stress 11-13 leading to the activation of kinases, MAPKs and their downstream signaling pathways 14 . Several strategies have been developed to limit DON toxicity 15 , among them, bacterial biotransformation which depends on the ability of microorganisms to generate DON metabolites with reduced toxicity. De-epoxidation is a reductive chemical reaction opening the 12,13-epoxy ring transforming DON into its de-epoxide metabolite de-epoxy-deoxynivalenol (deepoxy-DON or DOM-1) (Supplementary Figure S1) 16 . Several microbial strains are capable of DON de-epoxidation 15, 17 . Several in vitro studies demonstrated the reduced toxicity of deepoxy-DON. In vivo trials on farm animals receiving feed contaminated with DON have also shown a beneficial effect of the bacteria able to de-epoxidize DON, according to zootechnical parameters and immune response 18 . The hydroxyl on carbon 3 also seems to be significant for the toxic activity of DON and a detoxification strategy targeting this part of the C3-OH, leading to the formation of 3-epi-DON, was recently proposed 19 . Four bacterial strains, all isolated from soil, have been described to epimerize DON into 3-epi-DON 20,21 . Only one paper has investigated the effect of 3-epi-DON and demonstrated the lack of toxicity, both in vitro and in vivo, of this DON metabolite 22 . The aim of the current study was to assess the efficacy of microbial transformation through analysis of the intestinal toxicity of deepoxy-DON and 3-epi-DON. Using physiological, histological and transcriptomic analysis, we have observed reduced toxicity of deepoxy-DON and 3-epi-DON, both for human intestinal epithelial cells and pig intestinal explants. We have further demonstrated that these microbial metabolites of DON fit into the ribosome pocket but do not elicit ribotoxic stress or activate the MAPKinase pathway. Our paper provides the first molecular insight for the reduced toxicity of deepoxy-DON and 3-epi-DON.
Fumonisin B1 (FB1) is a widespread mycotoxin produced by fungal Fusarium species—mainly in maize, one of the plants most commonly used for food and feed. Pigs and horses are the animal species most susceptible to this mycotoxin. FB1 exposure can cause highly diverse clinical symptoms, including hepatotoxicity, immunotoxicity, and intestinal barrier function disturbance. Inhibition of ceramide synthetase is a well-understood ubiquitous molecular mechanism of FB1 toxicity, but other moredoi:10.3390/toxins14020083 pmid:35202111 pmcid:PMC8875869 fatcat:zwsuijq455dflib56enhbsj6de
more »... ecific effects remain to be elucidated. To investigate the effects of FB1 in different exposed tissues, we cross-analyzed the transcriptomes of fours organs: liver, jejunum, jejunal Peyer's patches, and spleen. During a four-week study period, pigs were fed a control diet or a FB1-contaminated diet (10 mg/kg feed). In response to oral FB1 exposure, we observed common biological processes in the four organs, including predominant and recurrent processes (extracellular matrix organization, integrin activation, granulocyte chemotaxis, neutrophil migration, and lipid and sterol homeostasis), as well as more tissue-specific processes that appeared to be related to lipid outcomes (cell cycle regulation in jejunum, and gluconeogenesis in liver).
Easily programming behaviors is one major issue of a large and reconfigurable deployment in the Internet of Things. Such kind of devices often requires to externalize part of their behavior such as the sensing, the data aggregation or the code offloading. Most existing context-oriented programming languages integrate in the same class or close layers the whole behavior. We propose to abstract and separate the context tracking from the decision process, and to use event-based handlers todoi:10.1145/2786545.2786552 dblp:conf/ecoop/MaingretMPSCL15 fatcat:gkhzrwk4yzeynborba6emcy7ja
more »... nect them. We keep a very easy declarative and non-layered programming model. We illustrate by defining an extension to Golo-a JVM-based dynamic language.
., 2006; Loiseau et al., 2007) . ... Al, Canlet, C., Tremblay-Franco, M., Ellero-Simatos, S., Langin, D., Postic, C., Wahli, W., Loiseau, N., Guillou, H., Montagner, A., 2020. ...doi:10.1101/2022.07.22.500801 fatcat:vvlm7nwugfbcvjfemxukggrmnm
AbstractObjectivesPeroxisome proliferator activated receptor α (PPARα) acts as a fatty acid sensor to orchestrate the transcription of genes coding for rate-limiting enzymes required for lipid oxidation in hepatocytes. Mice only lacking Pparα in hepatocytes spontaneously develop steatosis without obesity in aging. Altough steatosis is a benign condition it can develop into non alcoholic steatohepatitis (NASH), which may progress to irreversible damage, such as fibrosis and hepatocarcinoma.doi:10.1101/488031 fatcat:c4pk6urs2fdtlnydwakdmppzzm
more »... NASH appears as a major public health concern worldwide, it remains an unmet medical need. Several drugs are being tested in clinical trials, including pharmacological agonists for the different PPAR isotypes. In current study, we investigated the role of hepatocyte PPARα in a preclinical model of steatosis.Methods/ResultsWe have investigated the role of hepatocyte PPARα in a preclinical model of steatosis using High Fat Diet (HFD) feeding as a model of obesity in C57BL/6J male Wild-Type mice (WT), in whole-body (Pparα-/-) mice and in mice lacking Pparα in hepatocyte (Pparαhep-/-). We provide evidence that Pparα deletion in hepatocytes promotes NASH in mice fed an HFD. This enhanced NASH susceptibility occurs without development of glucose intolerance. Moreover, our data reveal that non-hepatocytic PPARα activity predominantly contributes to the metabolic response to HFD.ConclusionTaken together, our data support hepatocyte PPARα as being essential to the prevention of steatosis progression to NASH and that extra-hepatocyte PPARα activity contributes to whole-body lipid homeostasis.HighlightsPparα deletion in hepatocytes promotes steatosis and inflammation in HFD-induced obesityHepatocyte-specific deletion of Pparα dissociates NAFLD from glucose intolerance in HFD-induced obesity obesityExtrahepatic PPARα activity contributes to the metabolic response to HFD-induced obesity
Objective: In hepatocytes, peroxisome proliferator-activated receptor alpha acts as a lipid sensor that regulates hepatic lipid catabolism during fasting and orchestrates a genomic response required for whole-body homeostasis. This includes the biosynthesis of ketone bodies and the secretion of the starvation hormone fibroblast growth factor 21 (FGF21). Several lines of evidence suggest that adipose tissue lipolysis contributes to this specific process. However, whether adipose tissue lipolysisdoi:10.1101/2021.01.28.428684 fatcat:uqqjlrw5ebdg3okjx7g7n6h4wu
more »... is a dominant signal for the extensive remodeling of liver gene expression dependent on PPARalpha has not been investigated. Methods: First, using mice lacking adipose tissue lipolysis through adipocyte-specific deletion of adipose triglyceride lipase (ATGL), we characterized the responses dependent on adipocyte ATGL during fasting. Next, we performed liver whole genome expression analysis in fasted mice upon deletion of adipocyte ATGL or hepatocyte PPARalpha. Finally, we tested the consequences of hepatocyte-specific PPARalpha deficiency during pharmacological induction of adipocyte lipolysis with a Beta3-adrenergic receptor agonist. Results: In the absence of ATGL in adipocytes, ketone body and FGF21 productions were impaired in response to starvation. Liver transcriptome analysis revealed that adipocyte ATGL is critical for regulation of hepatic gene expression during fasting and highlighted a strong enrichment in PPARalpha target genes in this condition. Genome expression analysis confirmed that a large set of fasting-induced genes are sensitive to both ATGL and PPARalpha. Adipose tissue lipolysis induced by acute activation of the Beta3-adrenergic receptor also triggered PPARalpha-dependent responses in the liver, supporting a role for adipocyte-derived fatty acids as dominant signals for hepatocyte PPARalpha activity. In addition, the absence of hepatocyte PPARalpha altered brown adipose tissue (BAT) morphology and reduced UCP1 expression upon stimulation of the Beta3-adrenergic receptor. In agreement with this finding, mice lacking hepatocyte PPARalpha showed decreased tolerance to acute cold exposure. Conclusions: These results underscore the central role of hepatocyte PPARalpha in the sensing of adipocyte-derived fatty acids and reveal that its activity is essential for full activation of BAT. Intact PPARalpha activity in hepatocytes is required for cross-talk between adipose tissues and the liver during fat mobilization during fasting and cold exposure.
In mammalian cells, gene expression is rhythmic and sensitive to various environmental and physiological stimuli. A circadian clock system helps to anticipate and synchronize gene expression with daily stimuli including cyclic light and food intake, which control the central and peripheral clock programs, respectively. Food intake also regulates insulin secretion. How much insulin contributes to the effect of feeding on the entrainment of the clock and rhythmic gene expression remains to bedoi:10.1101/2021.02.05.430014 fatcat:bhe5fil6gbb5ratfnopqout32y
more »... stigated. An important component of insulin action is mediated by changes in insulin receptor (IR)-dependent gene expression. In the liver, insulin at high levels controls the transcription of hundreds of genes involved in glucose homeostasis to promote energy storage while repressing the expression of gluconeogenic genes. In type 2 diabetes mellitus (T2DM), selective hepatic insulin resistance impairs the inhibition of hepatic glucose production while promoting lipid synthesis. This pathogenic process promoting hyperlipidemia as well as non-alcoholic fatty liver diseases. While several lines of evidence link such metabolic diseases to defective control of circadian homeostasis, the hypothesis that IR directly synchronizes the clock has not been studied in vivo. Here, we used conditional hepatocyte-restricted gene deletion to evaluate the role of IR in the regulation and oscillation of gene expression as well as in the programming of the circadian clock in adult mouse liver.
F., Guillou, H., Loiseau, N. (Auteur de correspondance), Oswald, I. P. (Auteur de correspondance) (2017). ... F., Guillou, H., Loiseau, N. (Auteur de correspondance), Oswald, I. P. (Auteur de correspondance) (2017). ...doi:10.1002/mnfr.201700433 pmid:28875582 fatcat:t3ycgidxjzcc3jci52tlli6joy
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