217 research outputs found

    Pairwise Fused Lasso

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    In the last decade several estimators have been proposed that enforce the grouping property. A regularized estimate exhibits the grouping property if it selects groups of highly correlated predictor rather than selecting one representative. The pairwise fused lasso is related to fusion methods but does not assume that predictors have to be ordered. By penalizing parameters and differences between pairs of coefficients it selects predictors and enforces the grouping property. Two methods how to obtain estimates are given. The first is based on LARS and works for the linear model, the second is based on quadratic approximations and works in the more general case of generalized linear models. The method is evaluated in simulation studies and applied to real data sets

    Generalized Lasso Regularization for Regression Models

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    Partial Evaluation for Java Malware Detection

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    The fact that Java is platform independent gives hackers the opportunity to write exploits that can target users on any platform, which has a JVM implementation. Metasploit is a well-known source of Java exploits and to circumvent detection by Anti Virus (AV) software, obfuscation techniques are routinely applied to make an exploit more difficult to recognise. Popular obfuscation techniques for Java include string obfuscation and applying reflection to hide method calls; two techniques that can either be used together or independently. This paper shows how to apply partial evaluation to remove these obfuscations and thereby improve AV matching. The paper presents a partial evaluator for Jimple, which is a typed three-address code suitable for optimisation and program analysis, and also demonstrates how the residual Jimple code, when transformed back into Java, improves the detection rates of a number of commercial AV products

    Reference values of impulse oscillometric lung function indices in adults of advanced age.

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    Impulse oscillometry (IOS) is a non-demanding lung function test. Its diagnostic use may be particularly useful in patients of advanced age with physical or mental limitations unable to perform spirometry. Only few reference equations are available for Caucasians, none of them covering the old age. Here, we provide reference equations up to advanced age and compare them with currently available equations. IOS was performed in a population-based sample of 1990 subjects, aged 45-91 years, from KORA cohorts (Augsburg, Germany). From those, 397 never-smoking, lung healthy subjects with normal spirometry were identified and sex-specific quantile regression models with age, height and body weight as predictors for respiratory system impedance, resistance, reactance, and other parameters of IOS applied. Women (n = 243) showed higher resistance values than men (n = 154), while reactance at low frequencies (up to 20 Hz) was lower (p<0.05). A significant age dependency was observed for the difference between resistance values at 5 Hz and 20 Hz (R5-R20), the integrated area of low-frequency reactance (AX), and resonant frequency (Fres) in both sexes whereas reactance at 5 Hz (X5) was age dependent only in females. In the healthy subjects (n = 397), mean differences between observed values and predictions for resistance (5 Hz and 20 Hz) and reactance (5 Hz) ranged between -1% and 5% when using the present model. In contrast, differences based on the currently applied equations (Vogel & Smidt 1994) ranged between -34% and 76%. Regarding our equations the indices were beyond the limits of normal in 8.1% to 18.6% of the entire KORA cohort (n = 1990), and in 0.7% to 9.4% with the currently applied equations. Our study provides up-to-date reference equations for IOS in Caucasians aged 45 to 85 years. We suggest the use of the present equations particularly in advanced age in order to detect airway dysfunction

    Which early life events or current environmental and lifestyle factors influence lung function in adolescents? - results from the GINIplus & LISAplus studies

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    BACKGROUND: Various factors may affect lung function at different stages in life. Since investigations that simultaneously consider several factors are rare, we examined the relative importance of early life, current environmental/lifestyle factors and allergic diseases on lung function in 15-year-olds. METHODS: Best subset selection was performed for linear regression models to investigate associations between 21 diverse early life events and current factors with spirometric parameters (forced vital capacity, forced expiratory volume in 1 s and maximal mid-expiratory flow (FEF25-75)) in 1326 participants of the German GINIplus and LISAplus birth cohorts. To reduce model complexity, one model for each spirometric parameter was replicated 1000 times in random subpopulations (N = 884). Only those factors that were included in >70% of the replication models were retained in the final analysis. RESULTS: A higher peak weight velocity and early lung infections were the early life events prevalently associated with airflow limitation and FEF25-75. Current environmental/lifestyle factors at age 15 years and allergic diseases that were associated with lung function were: indoor second-hand smoke exposure, vitamin D concentration, body mass index (BMI) and asthma status. Sex and height captured the majority of the explained variance (>75%), followed by BMI (</=23.7%). The variance explained by early life events was comparatively low (median: 4.8%; range: 0.2-22.4%), but these events were consistently negatively associated with airway function. CONCLUSIONS: Although the explained variance was mainly captured by well-known factors included in lung function prediction equations, our findings indicate early life and current factors that should be considered in studies on lung health among adolescents

    Early age exposure to moisture and mould is related to FeNO at the age of 6 years

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    Background Exposure to indoor moisture damage and visible mold has been found to be associated with asthma and respiratory symptoms in several questionnaire-based studies by self-report. We aimed to define the prospective association between the early life exposure to residential moisture damage or mold and fractional exhaled nitric oxide (FeNO) and lung function parameters as objective markers for airway inflammation and asthma in 6-year-old children. Methods Home inspections were performed in children's homes when infants were on average 5 months old. At age 6 years, data on FeNO (n = 322) as well as lung function (n = 216) measurements were collected. Logistic regression and generalized additive models were used for statistical analyses. Results Early age major moisture damage and moisture damage or mold in the child's main living areas were significantly associated with increased FeNO levels (>75th percentile) at the age of 6 years (adjusted odds ratios, 95% confidence intervals, aOR (95% CI): 3.10 (1.35-7.07) and 3.16 (1.43-6.98), respectively. Effects were more pronounced in those who did not change residential address throughout the study period. For lung function, major structural damage within the whole home was associated with reduced FEV1 and FVC, but not with FEV1/FVC. No association with lung function was observed with early moisture damage or mold in the child's main living areas. Conclusion These results underline the importance of prevention and remediation efforts of moisture and mold-damaged buildings in order to avoid harmful effects within the vulnerable phase of the infants and children's immunologic development.Peer reviewe

    Opinion Cascades and Echo-Chambers in Online Networks: A Proof of Concept Agent-Based Model

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    In online networks, the polarization of opinions (e.g., regarding presidential elections or referenda) has been associated with the creation of “echo-chambers” of like-minded peers, secluded from those of contrary viewpoints. Previous work has commonly attributed such phenomena to self-regarding preferences (e.g., confirmation bias), individual differences, and the pre-dispositions of users, with clusters forming over repeated interactions. The present work provides a proof of concept Agent-Based Model that demonstrates online networks are susceptible to echo-chambers from a single opinion cascade, due to the spatiotemporal order induced by lateral transmission. This susceptibility is found to vary as a function of degree of interconnectivity and opinion strength. Critically, such effects are found despite globally proportionate levels of opinions, equally rational agents (i.e. absent conformity, confirmation bias or pre-disposition architecture), and prior to cyclical interactions. The assumptions and implications of this work, including the value of Agent-Based Modelling to cognitive psychology, are discussed

    Differential effects of lung inflammation on insulin resistance in humans and mice

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    BACKGROUND: The rates of obesity, its associated diseases, and allergies are raising at alarming rates in most countries. House dust mites (HDM) are highly allergenic and exposure often associates with an urban sedentary indoor lifestyle, also resulting in obesity. The aim of this study was to investigate the epidemiological association and physiological impact of lung inflammation on obesity and glucose homeostasis. METHODS: Epidemiological data from 2207 adults of the population-based KORA FF4 cohort were used to test associations between asthma and rhinitis with metrics of body weight and insulin sensitivity. To obtain functional insights, C57BL/6J mice were intranasally sensitized and challenged with HDM and simultaneously fed with either low-fat or high-fat diet for 12&nbsp;weeks followed by a detailed metabolic and biochemical phenotyping of the lung, liver, and adipose tissues. RESULTS: We found a direct association of asthma with insulin resistance but not body weight in humans. In mice, co-development of obesity and HDM-induced lung inflammation attenuated inflammation in lung and perigonadal fat, with little impact on body weight, but small shifts in the composition of gut microbiota. Exposure to HDM improved glucose tolerance, reduced hepatosteatosis, and increased energy expenditure and basal metabolic rate. These effects associate with increased activity of thermogenic adipose tissues independent of uncoupling protein 1. CONCLUSIONS: Asthma associates with insulin resistance in humans, but HDM challenge results in opposing effects on glucose homeostasis in mice due to increased energy expenditure, reduced adipose inflammation, and hepatosteatosis

    Associations between anthropometric indicators in early life and low-grade inflammation, insulin resistance and lipid profile in adolescence

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    Background and AimsThe long-term relations between excessive adiposity in early childhood and unfavourable cardiometabolic profiles in later ages are not yet completely understood. We aimed to assess the associations between birth weight (BW) and BMI from 6 months to 6 years of age, with biomarkers indicative of low-grade inflammation, insulin resistance and lipid profiles in adolescence.Methods and ResultsRetrospective school-based study with 415 Portuguese adolescents (220 girls), mean age of 14.08±1.6 years old. Anthropometric data from birth to 6 years old was extracted from individual child health book records. Actual weight and height were measured and BMI calculated. Participants were classified at each time point as normal weight or overweight according to WHO reference values. Biomarkers were obtained from venous blood samples. Linear regressions were used to explore the associations between the biomarkers and early life anthropometric indicators. From 2 years onwards, BMI associated positively with the inflammatory score and HOMA-IR in adolescence. Children who were overweight/obese from 2 to 6 years of age presented significantly higher inflammatory score and HOMA-IR later in adolescence. TC/HDL ratio was also positively associated with BMI from the age of 5 years onwards. The associations between BMI and cardiometabolic outcomes remained positive in adolescence, with overweight adolescents presenting a higher inflammatory score, HOMA-IR and TC/HDL than normal weight adolescents.ConclusionA high BMI from an early age was consistently associated with worse inflammatory and lipid profiles and insulin resistance in adolescence. No associations were found between BW and the same studied outcomes
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