Prediction of Search Targets From Fixations in Open-World Settings

Previous work on predicting the target of visual search from human fixations only considered closed-world settings in which training labels are available and predictions are performed for a known set of potential targets. In this work we go beyond the state of the art by studying search target prediction in an open-world setting in which we no longer assume that we have fixation data to train for the search targets. We present a dataset containing fixation data of 18 users searching for natural images from three image categories within synthesised image collages of about 80 images. In a closed-world baseline experiment we show that we can predict the correct target image out of a candidate set of five images. We then present a new problem formulation for search target prediction in the open-world setting that is based on learning compatibilities between fixations and potential targets

Sustainability of Open Source Software Projects: On the Influence of Technical Interdependencies in Software Ecosystems on Developer Participation

In the community-based model of open source software (OSS) development, OSS projects are built and maintained by developers that voluntarily contribute their skills, knowledge, and time, thus making them dependent on their continued participation. Therefore, the question of how projects can attract and retain developers is of major concern for their sustainability. OSS projects are embedded into a complex network of technical interdependent projects that emerges from building upon and reusing existing software components. In these so-called software ecosystems, the issue of sustained participation is not only a concern of a single project but also other dependent projects. However, the role and influence of these interdependencies between projects have so far been neglected by Information Systems researchers. This dissertation thus asks: _How do technical interdependencies in software ecosystems influence the sustainability of open source software projects?_ To answer this question, this dissertation consists of three independent empirical studies that focus on three aspects of how technical interdependencies influence developer participation and thus contribute to the sustainability of open source projects: (1) the ability to attract developers, (2) the influences on developers' participation decision, and (3) the retention of developers in a project. This dissertation finds that OSS projects attract more developers when depending on other projects and their ability to retain developers increases with the number of shared developers with other technical interrelated projects. Furthermore, the participation decisions of developers are also positively influenced by these technical relations. Together, these studies contribute to the body of knowledge on developer participation by highlighting the role of technical interdependencies for the overall sustainability of open source projects

The Mavuradonha Layered Complex

Der Mavuradonha Layered Complex repräsentiert einen 862 ? 4 Ma alten Komplex, der in einem tiefkrustalen Milieu intrudierte. Eine mehrphasige magmatische Differentiation ist in macro-rhythmischen Einheiten und kleinmaßstäblichen Lagenbau erkennbar, aus denen die Kristallisationssequenzen Pyroxenite, Gabbros/Norite, Leuko-Gabbros oder Ferro-Gabbro und Anorthosite resultieren. ?Nd-Werte zwischen + 0.3 und + 6.6 zeigen krustale Kontamination eines aus dem verarmten Mantel stammenden, tholeiitischen Ursprungsmagma an. ?Nd-Werte (+ 2.4 bis - 3.5) anderer tholeiitischer Gabbros in unmittelbarer Nähe des Komplexes deuten ebenfalls auf Krustenkontamination hin, jedoch in stärkerem Maße.Der Komplex wurde um 554 ? 13 Ma unter granulitfaziellen Bedingungen von 13 ? 2 kbar und 840 ? 30° C überprägt. Die anschließende retrograde, amphibolitfazielle Metamorphose mit Bedingungen von 11 ? 2 kbar und 680 ? 20° C ereignete sich um 546 ? 9 Ma. Abkühlung bis zur Grünschieferfazies erfolgte spätestens um 501 ? 6 Ma.Die vorgestellten Daten zeigen, dass sich der Sambesi-Gürtel im NE Simbabwes als fehlgeschlagenes Rift oder intrakratonisches Becken während einer frühen Pan-Afrikanischen Extensionsphase entwickelte, während die granulitfazielle Metamorphose um 300 Ma später erfolgte. Somit deutet die Intrusion des Mavuradonha Layered Complex rift-bedingten Magmatismus in einer frühen Riftphase an, während das Becken oder Rift während der Pan-Afrikanischen Orogenese geschlossen wurde.The Mavuradonha Layered Complex represents a lower crustal complex that was emplaced at about 862 ? 4 Ma. Multiphase magmatic differentiation produced macro rhythmic units and small-scale layering with sequences of pyroxenites, gabbro/norites, leuco-gabbros or ferro-gabbros, anorthosites. ?Nd values between + 0.3 and + 6.6 indicate crustal contamination of the tholeiitic, depleted mantle derived parental magma. Further tholeiitic gabbros nearby the complex indicate higher degrees of crustal contamination (?Nd ranging from + 2.4 to - 3.5).The complex was overprinted at about 554 ? 13 Ma by granulite-facies metamorphism with conditions of 13 ? 2 kbar at 840 ? 30° C followed by amphibolite-facies retrogression at about 546 ? 9 Ma (11 ? 2 kbar at 680 ? 20° C). Further cooling to greenschist-facies conditions occurred latest at 501 ? 6 Ma.The presented data suggest an evolution of the Zambezi belt in NE-Zimbabwe as a failed rift or an intracratonic basin during an early Pan-African extensional event. At least 300 Ma later occurred the granulite-facies regional metamorphism. Therefore, emplacement of the Mavuradonha Layered Complex represents an episode of intense plutonic activity during an early stage of rifting. The basin or failed rift was closed during the late Pan-African orogeny

The Influence of Dependency Networks on Developer Attraction in Open Source Software Ecosystems

Open source software projects rely on the continuous attraction of developers and therefore access to the pool of available developer resources. In modern software ecosystems, these projects are related through technical dependencies. In this study, we investigate the influence of these dependencies on a project’s ability to attract developers. We develop and test our hypothesis by observing the dependency networks and repository activities of 1832 projects in the JavaScript ecosystem. We find that dependencies to other projects have a positive effect on developer attraction while we did not find an effect of dependencies from other projects. Our study contributes theoretically and practically to the understanding of developer attraction and highlights the role of technical interdependencies in software ecosystems

The Role of Dependency Networks in Developer Participation Decisions in Open Source Software Ecosystems: An Application of Stochastic Actor-Oriented Models

Open source software relies on the contributions of developers who participate voluntarily in projects. While prior research has investigated social characteristics, relations, and connections that influence a developer’s participation, we argue that the technical relations and connections of projects, which emerge through dependencies between packages in software ecosystems, play a focal role in that decision as well. We empirically test these assertions by applying stochastic actor-oriented models to an affiliation network in the JavaScript software ecosystem. Our results show that while the number of dependencies of a project does not influence participation, developers are more likely to participate in projects to which their own projects have dependency relations. This study thereby contributes to the understanding of antecedents that influence developers’ participation decisions by highlighting the importance of project interdependencies in software ecosystems

Renal Involvement in Preeclampsia: Similarities to VEGF Ablation Therapy

Glomerular VEGF expression is critical for the maintenance and function of an intact filtration barrier. Alterations in glomerular VEGF bioavailability result in endothelial as well as in podocyte damage. Renal involvement in preeclampsia includes proteinuria, podocyturia, elevated blood pressure, edema, glomerular capillary endotheliosis, and thrombotic microangiopathy. At least the renal signs, symptoms, and other evidence can sufficiently be explained by reduced VEGF levels. The aim of this paper was to summarize our pathophysiological understanding of the renal involvement of preeclampsia and point out similarities to the renal side effects of VEGF-ablation therapy

HD 135344B: a young star has reached its rotational limit

We search for periodic variations in the radial velocity of the young Herbig star HD 135344B with the aim to determine a rotation period. We analyzed 44 high-resolution optical spectra taken over a time range of 151 days. The spectra were acquired with FEROS at the 2.2m MPG/ESO telescope in La Silla. The stellar parameters of HD 135344B are determined by fitting synthetic spectra to the stellar spectrum. In order to obtain radial velocity measurements, the stellar spectra have been cross-correlated with a theoretical template computed from determined stellar parameters. We report the first direct measurement of the rotation period of a Herbig star from radial-velocity measurements. The rotation period is found to be 0.16 d (3.9 hr), which makes HD 135344B a rapid rotator at or close to its break-up velocity. The rapid rotation could explain some of the properties of the circumstellar environment of HD 135344B such as the presence of an inner disk with properties (composition, inclination), that are significantly different from the outer disk.Comment: Accepted for publication in Astronomy & Astrophysics, 9 pages, 12 figure