University of Konstanz

About: University of Konstanz is a education organization based out in Konstanz, Baden-Württemberg, Germany. It is known for research contribution in the topics: Population & Membrane. The organization has 12115 authors who have published 27401 publications receiving 951162 citations. The organization is also known as: University of Constance & Universität Konstanz.

A quantum memory intrinsic to single nitrogen-vacancy centres in diamond

Abstract: A nitrogen impurity in diamond—where two of the carbon atoms are replaced by a nitrogen atom and a vacant lattice site—is seen as a valuable qubit. The spin of an electron localized to the nitrogen-vacancy centre is commonly used for processing. Researchers now show that this electron spin state can be transferred to the nitrogen nuclear spin, where it can be stored until needed.

Treatment of posttraumatic stress disorder by trained lay counselors in an African refugee settlement: a randomized controlled trial.

Abstract: Traumatic stress due to conflict and war causes major mental health problems in many resource-poor countries. The objective of this study was to examine whether trained lay counselors can carry out effective treatment of posttraumatic stress disorder (PTSD) in a refugee settlement. In a randomized controlled dissemination trial in Uganda with 277 Rwandan and Somalian refugees who were diagnosed with PTSD the authors investigated the effectiveness of psychotherapy administered by lay counselors. Strictly manualized narrative exposure therapy (NET) was compared with more flexible trauma counseling (TC) and a no-treatment monitoring group (MG). Fewer participants (4%) dropped out of NET treatment than TC (21%). Both active treatment groups were statistically and clinically superior to MG on PTSD symptoms and physical health but did not differ from each other. At follow-up, a PTSD diagnosis could not be established anymore in 70% of NET and 65% TC participants, whereas only 37% in MG did not meet PTSD criteria anymore. Short-term psychotherapy carried out by lay counselors with limited training can be effective to treat war-related PTSD in a refugee settlement.

Improving pairwise learning for item recommendation from implicit feedback

Abstract: Pairwise algorithms are popular for learning recommender systems from implicit feedback. For each user, or more generally context, they try to discriminate between a small set of selected items and the large set of remaining (irrelevant) items. Learning is typically based on stochastic gradient descent (SGD) with uniformly drawn pairs. In this work, we show that convergence of such SGD learning algorithms slows down considerably if the item popularity has a tailed distribution. We propose a non-uniform item sampler to overcome this problem. The proposed sampler is context-dependent and oversamples informative pairs to speed up convergence. An efficient implementation with constant amortized runtime costs is developed. Furthermore, it is shown how the proposed learning algorithm can be applied to a large class of recommender models. The properties of the new learning algorithm are studied empirically on two real-world recommender system problems. The experiments indicate that the proposed adaptive sampler improves the state-of-the art learning algorithm largely in convergence without negative effects on prediction quality or iteration runtime.

Hyperventilation Induces Release of Cytokines from Perfused Mouse Lung

Abstract: Artificial mechanical ventilation represents a major cause of iatrogenic lung damage in intensive care. It is largely unknown which mediators, if any, contribute to the onset of such complications. We investigated whether stress caused by artificial mechanical ventilation leads to induction, synthesis, and release of cytokines or eicosanoids from lung tissue. We used the isolated perfused and ventilated mouse lung where frequent perfusate sampling allows determination of mediator release into the perfusate. Hyperventilation was executed with either negative (NPV) or positive pressure ventilation (PPV) at a transpulmonary pressure that was increased 2.5-fold above normal. Both modes of hyperventilation resulted in an approximately 1.75-fold increased expression of tumor necrosis factor α (TNF α ) and interleukin-6 (IL-6) mRNA, but not of cyclooxygenase-2 mRNA. After switching to hyperventilation, prostacyclin release into the perfusate increased almost instantaneously from 19 ± 17 pg/ min to 230 ± 160 pg/m...