Free- und Open Source Software

Diese Arbeit betrachtet das Phänomen der Free und Open Source Software als privat bereitgestelltes öffentliches Gut. Nach einer Begriffsklärung und einer Abgrenzung von Software im Bereich der Informationsgüter, wird der Forschungsgegenstand in Bezug zum theoretischen Konzept der öffentlichen Güter gebracht. Die Entwicklung und Bereitstellung von Free und Open Source Software wird im Hauptteil der Arbeit anhand eines formalen Modells beschrieben. Dieses Modell entstand aus verschiedenen vorliegenden Modellen, die sich mit Teilaspekten der Thematik auseinandersetzen, und enthält neue Aspekte der Thematik. Zudem wurde in der Arbeit anhand verschiedener empirischer Studien auf die Motive der Entwickler, die zur privaten Bereitstellung dieses öffentlichen Gutes beitragen, eingegangen.This thesis regards Free and Open Source Software as a privately provided public good. Starting with a disambiguation and a classification of Software in the field of information goods, the thesis sets the object of research into context with the theoretical concept of public goods. The main part of the thesis describes the development and provision of Free and Open Source Software by means of a formal model. This model was generated from various existing models which deal with different aspects of the subject and contains new viewpoints of the topic. Furthermore the thesis contains a section dealing with the motives of the developers contributing to the private provision of this public good

The emergence of a self-catalysing structure in abstract origin-of-life models

We formalize a class of abstract and simple biochemical models that have been proposed for understanding the origin of life. We then analyse conditions under which 'life-like' substructures will tend to arise in such models

Dagstuhl-Manifest zur Strategischen Bedeutung des Software Engineering in Deutschland

Im Rahmen des Dagstuhl Perspektiven Workshop 05402 "Challenges for Software Engineering Research" haben führende Software Engineering Professoren den derzeitigen Stand der Softwaretechnik in Deutschland charakterisiert und Handlungsempfehlungen für Wirtschaft, Forschung und Politik abgeleitet. Das Manifest fasst die diese Empfehlungen und die Bedeutung und Entwicklung des Fachgebiets prägnant zusammen

Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition

Parameter estimation, bias correction and uncertainty quantification in the Vasicek credit portfolio model

This paper is devoted to the parameterization of correlations in the Vasicek credit portfolio model. First, we analytically approximate standard errors for value-at-risk and expected shortfall based on the standard errors of intra-cohort correlations. Second, we introduce a novel copula-based maximum likelihood estimator for inter-cohort correlations and derive an analytical expression of the standard errors. Our new approach enhances current methods in terms of both computing time and, most importantly, direct uncertainty quantification. Both contributions can be used to quantify a margin of conservatism, which is required by regulators. Third, we illustrate powerful procedures that reduce the well-known bias of current estimators, showing their favorable properties. Further, an open-source implementation of all estimators in the novel R package AssetCorr is provided and selected estimators are applied to Moody’s Default & Recovery Database

Reservas lipídicas del salmonete de fango (Mullus barbatus) durante la prepuesta en el Mediterráneo noroccidental

[EN] Lipid reserves are a particularly important attribute of fishes because they have a large influence on growth, reproduction and survival. This study analyses the lipid content of red mullet (Mullus barbatus) pre-spawners in three different areas of the northwestern Mediterranean in relation to trawling activities and river runoff. The muscle lipid was considered as an indicator of the somatic condition of individuals whilst the gonad lipid was used as a proxy of the energy invested in reproduction. The results show that fish with the highest muscle lipid levels inhabited the area where fishing impact was lowest. Since the abundance and biomass of polychaetes, which represent the main food source for red mullet, were found to be lower in trawled zones than in unfished ones, we suggest that differences in the muscle lipid levels between areas might be attributed to variation in prey abundance in relation to fishing impact. However, no impact of river runoff on lipid reserves of red mullet was observed. The results also show that muscle and gonad lipid reserves are not related to each other during pre-spawning[ES] Las reservas lipídicas constituyen un importante atributo de los peces porque juegan un papel destacado en su crecimiento, reproducción y supervivencia. Este estudio analiza las reservas lipídicas del salmonete de fango (Mullus barbatus) durante la prepuesta en tres áreas diferentes del Mediterráneo noroccidental en relación a la actividad pesquera y las descargas fluviales. Se ha considerado el contenido lipídico en el músculo y en la gónada como indicadores de la condición somática y de la energía invertida en la reproducción de los individuos respectivamente. Los resultados muestran cómo los peces con una cantidad mayor de lípidos en el músculo habitan el área donde el impacto pesquero es menor. Puesto que la abundancia y la biomasa de poliquetos, que constituyen la principal fuente de alimento del salmonete de fango, son inferiores en las zonas afectadas por el arrastre que en las zonas donde no se practica este tipo de pesca, se sugiere que las diferencias en la cantidad de lípidos en el músculo entre las distintas áreas podrían atribuirse a las diferencias en la abundancia de presas, lo cual podría guardar relación con la actividad pesquera. Sin embargo, no se observa impacto alguno de las descargas fluviales sobre las reservas de lípidos del salmonete de fango. Los resultados también muestran cómo los contenidos lipídicos en el músculo y en la gónada de los ejemplares no están relacionados entre sí durante la prepuesta de la especieThis research was funded by a Marie Curie European Reintegration Grant (MERG) of the European Commission and a C-RED Fellowship from the Government of Catalonia (Spain)Peer reviewe

Method for simultaneous luminescence sensing of two species using optical probes of different decay time, and its application to an enzymatic reaction at varying temperature

Chemical sensing, imaging and microscopy based on the use of fluorescent probes has so far been limited almost exclusively to the detection of a single parameter at a time. We present a scheme that can overcome this limitation by enabling optical sensing of two parameter simultaneously and even at identical excitation and emission wavelengths of two probes provided (a) their decay times are different enough to enable two time windows to be recorded, and (b) the emission of the shorter-lived probe decays to below the detectable limit while that of the other still can be measured. We refer to this new scheme as the dual lifetime determination (DLD) method and show that it can be widely varied by appropriate choice of probes and experimental settings. DLD is demonstrated to work by sensing oxygen and temperature independently from each other by making use of two probes, one for oxygen (a platinum porphyrin dissolved in polystyrene), and one for temperature [a europium complex dissolved in poly(vinyl methylketone)]. DLD was applied to monitor the consumption of oxygen in the glucose oxidase-catalyzed oxidation of glucose at varying temperatures. The scheme is expected to have further applications in cellular assays and biophysical imaging