Determining maximum k-width-connectivity on meshes

AbstractLet I be a n × n binary image stored in a n × n mesh of processors with one pixel per processor. Image I is k-width-connected if, informally, between any pair of 1-pixels there exists a path of width k (composed of 1-pixels only). We consider the problem of determining the largest integer k such that I is k-width-connected, and present an optimal O(n) time algorithm for the mesh architecture

Aus der Not eine Tugend machen? Ethische, juristische und praktische Implikationen funktionaler Psychopathen in Wirtschaft und Gesellschaft

Das Themengebiet der Psychopathie hat in den letzten Jahrzehnten vor allem durch Filme, die sich mit (vermeintlich) psychopathischen Charakteren beschäfti- gen, ein breites gesellschaftliches Interesse erfahren (vgl. Swart 2016). Holly- woods Blockbuster zeigen hier Beispiele hochintelligenter (z. B. Hanibal Lector in „Das Schweigen der Lämmer“) oder sexuell devianter (z. B. Patrick Bateman in „American Psycho“) Serienkiller, welche aus klinischer Sicht tatsächlich hoch psy- chopathische Tendenzen aufweisen. Demgegenüber werden psychisch andersartig beeinträchtigte Filmcharaktere, wie z. B. Norman Bates („Psycho“) oder Travis Bickel („Taxi Driver“) wohl aufgrund ihrer schreckenseinflößenden Wirkung im allgemeinen Sprachgebrauch oft als Psychopathen bezeichnet, obwohl ihre Symptome aus forensisch-psychiatrischer Sicht eher schizoiden Wahnvorstellungen ähneln und keine Anzeichen einer klas- sischen Psychopathie darstellen (vgl. Leistedt / Linkowski 2014). Auch Medienbe- richte über tatsächlich existierende, brutale (z.B. Serienkiller Ted Bundy) oder dreiste (z.B. Anlagebetrüger Bernard Madoff) Figuren der Zeitgeschichte haben die konzeptionelle Unübersichtlichkeit des in der Öffentlichkeit wahrgenommenen Bildes der Psychopathie befeuert. Und sogar in medizinischen bzw. psychiatri- schen Kreisen scheint eine uneinheitliche Sichtweise die Konfusion um das Stö- rungsbild Psychopathie weiter anzufachen (vgl. Berg et al. 2013)

Distance Oracles for Time-Dependent Networks

We present the first approximate distance oracle for sparse directed networks with time-dependent arc-travel-times determined by continuous, piecewise linear, positive functions possessing the FIFO property. Our approach precomputes $(1+\epsilon)-$approximate distance summaries from selected landmark vertices to all other vertices in the network. Our oracle uses subquadratic space and time preprocessing, and provides two sublinear-time query algorithms that deliver constant and $(1+\sigma)-$approximate shortest-travel-times, respectively, for arbitrary origin-destination pairs in the network, for any constant $\sigma > \epsilon$. Our oracle is based only on the sparsity of the network, along with two quite natural assumptions about travel-time functions which allow the smooth transition towards asymmetric and time-dependent distance metrics.Comment: A preliminary version appeared as Technical Report ECOMPASS-TR-025 of EU funded research project eCOMPASS (http://www.ecompass-project.eu/). An extended abstract also appeared in the 41st International Colloquium on Automata, Languages, and Programming (ICALP 2014, track-A

Understanding Methods for Estimating HIV-Associated Maternal Mortality

The impact of HIV on maternal mortality and more broadly on the health of women, remains poorly documented and understood. Two recent reports attempt to address the conceptual and methodological challenges that arise in estimating HIV-related maternal mortality and trends. This paper presents and compares the methods and discusses how they affect estimates at global and regional levels. Country examples of likely patterns of mortality among women of reproductive age are provided to illustrate the critical interactions between HIV and complications of pregnancy in high-HIV-burden countries. The implications for collaboration between HIV and reproductive health programmes are discussed, in support of accelerated action to reach the Millennium Development Goals and improve the health of women

HIV decline in Zimbabwe due to reductions in risky sex? Evidence from a comprehensive epidemiological review.

Published versio

On Feedback Vertex Set: New Measure and New Structures

We present a new parameterized algorithm for the {feedback vertex set} problem ({\sc fvs}) on undirected graphs. We approach the problem by considering a variation of it, the {disjoint feedback vertex set} problem ({\sc disjoint-fvs}), which finds a feedback vertex set of size $k$ that has no overlap with a given feedback vertex set $F$ of the graph $G$. We develop an improved kernelization algorithm for {\sc disjoint-fvs} and show that {\sc disjoint-fvs} can be solved in polynomial time when all vertices in $G \setminus F$ have degrees upper bounded by three. We then propose a new branch-and-search process on {\sc disjoint-fvs}, and introduce a new branch-and-search measure. The process effectively reduces a given graph to a graph on which {\sc disjoint-fvs} becomes polynomial-time solvable, and the new measure more accurately evaluates the efficiency of the process. These algorithmic and combinatorial studies enable us to develop an $O^*(3.83^k)$-time parameterized algorithm for the general {\sc fvs} problem, improving all previous algorithms for the problem.Comment: Final version, to appear in Algorithmic

HIV and maternal mortality: turning the tide

The two top causes of death in women of reproductive age globally are HIV/AIDS and complications related to pregnancy and childbearing, which account for 19% and 15% of all deaths in women aged 15–44 years, respectively. The growing burden of HIV infection in young sexually active women and the maternal health problems that they face have been described as two intersecting epidemics. In settings with a high HIV burden and high maternal mortality ratios, especially in sub-Saharan Africa, many HIV-infected pregnant women are confronted not only with the risk of death associated with advancing HIV disease, but also with an increased risk of pregnancy-related death

Social representations of HIV/AIDS in five Central European and Eastern European countries: A multidimensional analysis

Cognitive processing models of risky sexual behaviour have proliferated in the two decades since the first reporting of HIV/AIDS, but far less attention has been paid to individual and group representations of the epidemic and the relationship between these representations and reported sexual behaviours. In this study, 494 business people and medics from Estonia, Georgia, Hungary, Poland and Russia sorted free associations around HIV/AIDS in a matrix completion task. Exploratory factor and multidimensional scaling analyses revealed two main dimensions (labelled ‘Sex’ and ‘Deadly disease’), with significant cultural and gender variations along both dimension scores. Possible explanations for these results are discussed in the light of growing concerns over the spread of the epidemic in this region