Das MINERVA-Projekt: Datenbankselektion für Peer-to-Peer-Websuche

In diesem Artikel wird MINERVA pr?sentiert, eine prototypische Implementierung einer verteilten Suchmaschine basierend auf einer Peer-to-Peer (P2P)-Architektur. MINERVA setzt auf die in der P2P-Welt verbreitete Technik verteilter Hash-Tabellen auf und benutzt diese zum Aufbau eines verteilten Verzeichnisses. Peers in unserem Ansatz entsprechen v?llig autonomen Benutzern mit ihren lokalen Suchm"oglichkeiten, die bereit sind, ihr lokales Wissen und ihre lokalen Suchm?glichkeiten im Rahmen einer Kollaboration zur Verfügung zu stellen. Wir formalisieren unsere Systemarchitektur und beschreiben das zentrale Problem einer effizienten Suche nach vielversprechenden Peers für eine konkrete Anfrage innerhalb des Verbundes. Wir greifen dabei auf existierende Methoden zurück and passen diese an unseren Systemkontext an. Wir pr?sentieren Experimente auf realen Daten, die verschiedene dieser Ans?tze vergleichen. Diese Experimente zeigen, dass die Qualit?t der Ans?tze variiert und untermauern damit die Wichtigkeit und den Einfluss einer leistungsstarken Methode zur Auswahl guter Datenbanken. Unsere Experimente deuten an, dass eine geringe Anzahl sorgf?ltig ausgew?hlter Datenbanken typischerweise bereits einen Gro?teil aller relevanten Ergebnisse des Gesamtsystems liefert.     

Formation of embryoid bodies using dielectrophoresis

Embryoid body (EB) formation forms an important step in embryonic stem cell differentiation invivo. In murine embryonic stem cell (mESC) cultures EB formation is inhibited by the inclusion of leukaemic inhibitory factor (LIF) in the medium. Assembly of mESCs into aggregates by positive dielectrophoresis (DEP) in high field regions between interdigitated oppositely castellated electrodes was found to initiate EB formation. Embryoid body formation in aggregates formed with DEP occurred at a more rapid rate-in fact faster compared to conventional methods-in medium without LIF. However, EB formation also occurred in medium in which LIF was present when the cells were aggregated with DEP. The optimum characteristic size for the electrodes for EB formation with DEP was found to be 75-100 microns; aggregates smaller than this tended to merge, whilst aggregates larger than this tended to split to form multiple EBs. Experiments with ESCs in which green fluorescent protein (GFP) production was targeted to the mesodermal gene brachyury indicated that differentiation within embryoid bodies of this size may preferentially occur along the mesoderm lineage. As hematopoietic lineages during normal development derive from mesoderm, the finding points to a possible application of DEP formed EBs in the production of blood-based products from ESCs.     

Redefining Successful Interpretation in Art Museums

Abstract This article aims to capture the spirit and content of a lively exchange among museum staff members at the Denver Art Museum. It began as a conference call and continued as an online dialogue about how definitions of success have evolved with advances in technology and changing expectations of visitors. Together we explored how DAM staff encourage more active participation in the museum and the creative tension that ensues between visitor co‐creation and institutional control. Woven throughout this conversation are examples that demonstrate the need to move fluidly between high tech and low tech interpretives, onsite and online experiences, and the impact of environments that break down museum stereotypes. It is our hope that this discussion will spark similar dialogues among colleagues in individual institutions and in the profession at large. Readers are encouraged to respond through the blog at Curator’s new website: http://www.curatorjournal.org .     

Evaluating the Influence of an Urban High School Reform Effort on College Readiness and Access Outcomes: A Quasiexperimental Cohort Study

It is widely accepted that postsecondary education has become a necessity for US youth. College access, however, has been found not to be equal for all. As a result, federally funded college-readiness programs, such as Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP), have been established to increase the numbers of economically disadvantaged students with access to college. This quasiexperimental case study compared academic and nonacademic college-readiness indicators between cohorts of GEAR UP students and nonparticipants in 1 urban high school. Overall, cohorts of GEAR UP students outperformed their non-GEAR UP peers on all measures (grade-point average, attendance rate, behavior, graduation rate, and college enrollment) despite a dramatic demographic shift that led to greater proportions of educationally disadvantaged students in the GEAR UP cohorts.     

A high resolution laser scanning model of the Roman theater in Pinara,Turkey – comparison to previous measurements and search for the causes of damage

The archaeological site Pinara, southwest Turkey, which includes several remarkable objects of cultural heritage, has been the focus of several previous archaeoseismic studies. One of these examined the setting of the Roman theater in the east of Pinara by a lidar survey. A gross inclination of the stone rows of the auditorium of 0.81° towards N 314°E was interpreted as a consequence of recent coseismic tectonic movements. A new survey of the theater with a terrestrial phase laser scanner is the basis for a model with 15 times higher resolution and 28 times more data points. Parallel to the fieldwork in this study, the process and accuracy of the leveling of the 3D point clouds produced by the scanner was tested in a series of experiments. Based on the orientation of the blocks forming the seats of the theater, we suggest six sections with changing average inclination of the seats and a fault line separating a northern and a southern section. While the previously found overall inclination of the auditorium is confirmed by the new model and the dip direction agrees, the inclination is 0.58° compared to previously determined 0.81°. The almost perfect increase of inclination with the height of the first 10 entire seating rows and the nearly constant inclination from row 11 onward, makes systematic measurement errors during the construction a possible cause. This is an alternative scenario to the interpretation of a coseismic displacement of the conglomerate block on which the theater was built.     

Soviet military maps and archaeological survey in the Samarkand region

In Central Asia, the introduction of mechanised farming and the transformation of the landscape caused by agricultural intensification over the last 50 years have resulted in the massive destruction of archaeological remains. In this paper, we focus on an underestimated and unexploited type of remote sensing for the study of landscape change and anthropic impact on cultural heritage: 1:10,000 Soviet military maps of the 1950s. We present their use in the case study of the Archaeological Map of the Samarkand region. We argue that their precision and the early date at which they were produced make it possible to employ them as a reference tool for systematic survey and archaeological heritage management in Central Asia and throughout the former Soviet Union. We discuss the results of an archaeological survey based on these maps and show how they can be used to evaluate the destruction of archaeological mounds during the last 50 years, by contrasting them with modern satellite imagery.     

Information ambiguity,patents and the market value of innovative assets

Research and development (R&D) is often essential for firms’ profitability and growth. At the same time, R&D is long-term and risky. We show that innovation activities lead to information ambiguity about the future value of firms’ assets. This effect appears to be more pronounced for small and less reputed firms. Information ambiguity further lowers firms’ market value and, in particular, the market value of innovative assets. We further show that high quality patents mitigate the negative effect of information ambiguity to some extent.     

More is not always better: Effects of collaboration breadth and depth on radical and incremental innovation performance at the project level

This study investigates the effect of project-level collaboration breadth (i.e., the number of collaboration partner types) and collaboration depth (i.e., the intensity of the interactions with these partners) on the incremental and radical innovation performance of innovation projects. The econometric analyses, based on a Community Innovation Study sample of 218 innovation projects conducted in German manufacturing companies, reveal inverted U-shaped relationships between collaboration breadth and radical innovation performance and between collaboration depth and incremental innovation performance. These curvilinear effects speak to the high sensitivity of innovation projects to the extent of collaborative activity, which implies that practitioners should exert caution in managing collaborative innovation projects. This study contributes to the understanding of project-level open innovation and to the overall understanding of the performance effects of innovation collaboration, which, following recent assertions in the literature, could be flawed by analyses conducted at the organizational level.