Efficient Algorithms for Distributed Detection of Holes and Boundaries in Wireless Networks

We propose two novel algorithms for distributed and location-free boundary recognition in wireless sensor networks. Both approaches enable a node to decide autonomously whether it is a boundary node, based solely on connectivity information of a small neighborhood. This makes our algorithms highly applicable for dynamic networks where nodes can move or become inoperative. We compare our algorithms qualitatively and quantitatively with several previous approaches. In extensive simulations, we consider various models and scenarios. Although our algorithms use less information than most other approaches, they produce significantly better results. They are very robust against variations in node degree and do not rely on simplified assumptions of the communication model. Moreover, they are much easier to implement on real sensor nodes than most existing approaches.Comment: extended version of accepted submission to SEA 201

Drawing Binary Tanglegrams: An Experimental Evaluation

A binary tanglegram is a pair of binary trees whose leaf sets are in one-to-one correspondence; matching leaves are connected by inter-tree edges. For applications, for example in phylogenetics or software engineering, it is required that the individual trees are drawn crossing-free. A natural optimization problem, denoted tanglegram layout problem, is thus to minimize the number of crossings between inter-tree edges. The tanglegram layout problem is NP-hard and is currently considered both in application domains and theory. In this paper we present an experimental comparison of a recursive algorithm of Buchin et al., our variant of their algorithm, the algorithm hierarchy sort of Holten and van Wijk, and an integer quadratic program that yields optimal solutions.Comment: see http://www.siam.org/proceedings/alenex/2009/alx09_011_nollenburgm.pd

The Foundations of Human Pro-Social Behaviour: Some Economic Aspects

Pro-social behaviour has an economic foundation. Income rate, social discount rates, incentives and welfare motives force agents to act pro-socially. Pro-social behaviour is realized through the institution of social responsibility, which includes non-market coordination mechanism, altruism, social capital and trust. The nature of the institute of social responsibility and its components are described in the first part of the paper. The second part describes the conditions that promote pro-social behaviour and reflect the main features of the institute of social responsibility. In the third part we tested the hypothesis of the second part on the basis of a comparative analysis of pro-social behaviour in Russia and OECD countries. In the fourth part we summed up the conclusions of the study. The study found a direct connection between the pro-social behaviour, the level of trust, volunteer and charitable activities. For empirical testing of theoretical hypotheses we use sociological surveys data of WVS (2010-2014), ESS (2012). In this paper we evaluated the pro-social behaviour in Russia in comparison with OECD countries. We used the following indicators: positive expectations for the future, trust, participation in volunteer activities and charity. We found that pro-social activity is poorly implemented in Russia. The low level of per capita income, low level of interpersonal trust, weak development of volunteer and charitable activities and pessimistic expectations of the future - these are the key factors that reduce pro-social activity in Russia

Konzepte und Strategien für ein zielfunktionsorientiertes Prozess-Mapping von Mitarbeiter-Ressourcen innerhalb der Auftragsfertigung

Der Planungsprozess des Produktionsablaufes ist insbesondere in personalintensiven Bereichen durch einen hohen Komplexitätsgrad gekennzeichnet. Dies gilt nicht allein für die Domäne der Fertigung von Industriegütern, sondern ist überall dort charakteristisch, wo projektähnliche Aufgaben und Tätigkeiten im Kurzfristbereich hinsichtlich Ressourcenzuteilung determiniert werden müssen. Personal ist hierbei weitaus weniger homogen, als dies auf andere Ressourcentypen zutrifft. Daher gilt es der Heterogenität der Prozesse und Strukturen unter Beachtung individuell ausgeprägter Eigenschaften und Fähigkeiten des Personals einen quantitativ beschreibbaren und damit operationali-sierbaren Rahmen zu geben. Die Komplexität einer personalbezogenen, zielfunktionsorientierten Zuteilungsentscheidung kann im Kontext der Kapazitätsplanung damit signifikant reduziert werden

PROGRESS – prospective observational study on hospitalized community acquired pneumonia

Background: Community acquired pneumonia (CAP) is a high incidence disease resulting in about 260,000 hospital admissions per year in Germany, more than myocardial infarction or stroke. Worldwide, CAP is the most frequent infectious disease with high lethality ranging from 1.2 % in those 20–29 years old to over 10 % in patients older than 70 years, even in industrial nations. CAP poses numerous medical challenges, which the PROGRESS (Pneumonia Research Network on Genetic Resistance and Susceptibility for the Evolution of Severe Sepsis) network aims to tackle: Operationalization of disease severity throughout the course of disease, outcome prediction for hospitalized patients and prediction of transitions from uncomplicated CAP to severe CAP, and finally, to CAP with sepsis and organ failure as a life-threatening condition. It is a major aim of PROGRESS to understand and predict patient heterogeneity regarding outcome in the hospital and to develop novel treatment concepts. Methods: PROGRESS was designed as a clinical, observational, multi-center study of patients with CAP requiring hospitalization. More than 1600 patients selected for low burden of co-morbidities have been enrolled, aiming at a total of 3000. Course of disease, along with therapy, was closely monitored by daily assessments and long-term follow-up. Daily blood samples allow in depth molecular-genetic characterization of patients. We established a well-organized workflow for sample logistics and a comprehensive data management system to collect and manage data from more than 50 study centers in Germany and Austria. Samples are stored in a central biobank and clinical data are stored in a central data base which also integrates all data from molecular assessments. Discussion: With the PROGRESS study, we established a comprehensive data base of high quality clinical and molecular data allowing investigation of pressing research questions regarding CAP. In-depth molecular characterization will contribute to the discovery of disease mechanisms and establishment of diagnostic and predictive biomarkers. A strength of PROGRESS is the focus on younger patients with low burden of co-morbidities, allowing a more direct look at host biology with less confounding. As a resulting limitation, insights from PROGRESS will require validation in representative patient cohorts to assess clinical utility. Trial registration: The PROGRESS study was retrospectively registered on May 24th, 2016 with ClinicalTrials.gov: NCT0278201

Predictive Value of HAS-BLED Score Regarding Bleeding Events and Graft Survival following Renal Transplantation

Objective: Due to the high prevalence and incidence of cardio- and cerebrovascular diseases among dialysis-dependent patients with end-stage renal disease (ERSD) scheduled for kidney transplantation (KT), the use of antiplatelet therapy (APT) and/or anticoagulant drugs in this patient population is common. However, these patients share a high risk of complications, either due to thromboembolic or bleeding events, which makes adequate peri- and post-transplant anticoagulation management challenging. Predictive clinical models, such as the HAS-BLED score developed for predicting major bleeding events in patients under anticoagulation therapy, could be helpful tools for the optimization of antithrombotic management and could reduce peri- and postoperative morbidity and mortality. Methods: Data from 204 patients undergoing kidney transplantation (KT) between 2011 and 2018 at the University Hospital Leipzig were retrospectively analyzed. Patients were stratified and categorized postoperatively into the prophylaxis group (group A)—patients without pretransplant anticoagulation/antiplatelet therapy and receiving postoperative heparin in prophylactic doses—and into the (sub)therapeutic group (group B)—patients with postoperative continued use of pretransplant antithrombotic medication used (sub)therapeutically. The primary outcome was the incidence of postoperative bleeding events, which was evaluated for a possible association with the use of antithrombotic therapy. Secondary analyses were conducted for the associations of other potential risk factors, specifically the HAS-BLED score, with allograft outcome. Univariate and multivariate logistic regression as well as a Cox proportional hazard model were used to identify risk factors for long-term allograft function, outcome and survival. The calibration and prognostic accuracy of the risk models were evaluated using the Hosmer–Lemshow test (HLT) and the area under the receiver operating characteristic curve (AUC) model. Results: In total, 94 of 204 (47%) patients received (sub)therapeutic antithrombotic therapy after transplantation and 108 (53%) patients received prophylactic antithrombotic therapy. A total of 61 (29%) patients showed signs of postoperative bleeding. The incidence (p < 0.01) and timepoint of bleeding (p < 0.01) varied significantly between the different antithrombotic treatment groups. After applying multivariate analyses, pre-existing cardiovascular disease (CVD) (OR 2.89 (95% CI: 1.02–8.21); p = 0.04), procedure-specific complications (blood loss (OR 1.03 (95% CI: 1.0–1.05); p = 0.014), Clavien–Dindo classification > grade II (OR 1.03 (95% CI: 1.0–1.05); p = 0.018)), HAS-BLED score (OR 1.49 (95% CI: 1.08–2.07); p = 0.018), vit K antagonists (VKA) (OR 5.89 (95% CI: 1.10–31.28); p = 0.037), the combination of APT and therapeutic heparin (OR 5.44 (95% CI: 1.33–22.31); p = 0.018) as well as postoperative therapeutic heparin (OR 3.37 (95% CI: 1.37–8.26); p < 0.01) were independently associated with an increased risk for bleeding. The intraoperative use of heparin, prior antiplatelet therapy and APT in combination with prophylactic heparin was not associated with increased bleeding risk. Higher recipient body mass index (BMI) (OR 0.32 per 10 kg/m2 increase in BMI (95% CI: 0.12–0.91); p = 0.023) as well as living donor KT (OR 0.43 (95% CI: 0.18–0.94); p = 0.036) were associated with a decreased risk for bleeding. Regarding bleeding events and graft failure, the HAS-BLED risk model demonstrated good calibration (bleeding and graft failure: HLT: chi-square: 4.572, p = 0.802, versus chi-square: 6.52, p = 0.18, respectively) and moderate predictive performance (bleeding AUC: 0.72 (0.63–0.79); graft failure: AUC: 0.7 (0.6–0.78)). Conclusions: In our current study, we could demonstrate the HAS-BLED risk score as a helpful tool with acceptable predictive accuracy regarding bleeding events and graft failure following KT. The intensified monitoring and precise stratification/assessment of bleeding risk factors may be helpful in identifying patients at higher risks of bleeding, improved individualized anticoagulation decisions and choices of antithrombotic therapy in order to optimize outcome after kidney transplantatio

Characterization of a short isoform of the kidney protein podocin in human kidney

BACKGROUND: Steroid resistant nephrotic syndrome is a severe hereditary disease often caused by mutations in the NPHS2 gene. This gene encodes the lipid binding protein podocin which localizes to the slit diaphragm of podocytes and is essential for the maintenance of an intact glomerular filtration barrier. Podocin is a hairpin-like membrane-associated protein that multimerizes to recruit lipids of the plasma membrane. Recent evidence suggested that podocin may exist in a canonical, well-studied large isoform and an ill-defined short isoform. Conclusive proof of the presence of this new podocin protein in the human system is still lacking. METHODS: We used database analyses to identify organisms for which an alternative splice variant has been annotated. Mass spectrometry was employed to prove the presence of the shorter isoform of podocin in human kidney lysates. Immunofluorescence, sucrose density gradient fractionation and PNGase-F assays were used to characterize this short isoform of human podocin. RESULTS: Mass spectrometry revealed the existence of the short isoform of human podocin on protein level. We cloned the coding sequence from a human kidney cDNA library and showed that the expressed short variant was retained in the endoplasmic reticulum while still associating with detergent-resistant membrane fractions in sucrose gradient density centrifugation. The protein is partially N-glycosylated which implies the presence of a transmembranous form of the short isoform. CONCLUSIONS: A second isoform of human podocin is expressed in the kidney. This isoform lacks part of the PHB domain. It can be detected on protein level. Distinct subcellular localization suggests a physiological role for this isoform which may be different from the well-studied canonical variant. Possibly, the short isoform influences lipid and protein composition of the slit diaphragm complex by sequestration of lipid and protein interactors into the endoplasmic reticulum

sPLINK : a hybrid federated tool as a robust alternative to meta-analysis in genome-wide association studies

Meta-analysis has been established as an effective approach to combining summary statistics of several genome-wide association studies (GWAS). However, the accuracy of meta-analysis can be attenuated in the presence of cross-study heterogeneity. We present sPLINK, a hybrid federated and user-friendly tool, which performs privacy-aware GWAS on distributed datasets while preserving the accuracy of the results. sPLINK is robust against heterogeneous distributions of data across cohorts while meta-analysis considerably loses accuracy in such scenarios. sPLINK achieves practical runtime and acceptable network usage for chi-square and linear/logistic regression tests.Peer reviewe

Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD