GD 99 - an unusual, rarely observed DAV white dwarf

New observations of GD 99 are analysed. The unusual pulsation behaviour, showing both long and short periods, has been confirmed. All the available periods show a grouping of short and long period modes with roughly regular spacing. If we interpret the groups separately, a binary nature can be a possible explanation as in the similar cases of WD 2350-0054 and G29-38.Comment: 2 pages, 1 eps figure; has been accepted for publication in Communications in Asteroseismology (Vol. 150, 2007), Proceedings of the Vienna Workshop on the Future of Asteroseismolog

Interview with Frank Petry on ‘‘Digital Entrepreneurship: Opportunities, Challenges, and Impacts’’

Frank Petry is a primal rock of Germany's startup scene. He is a serial founder, serial investor (e.g., Ticketmaster, Expedia, Lending Tree, Web.de, ESCOM), partner and member of the Advisory Board at Blue Lake VC, as well as a partner, mentor and advisory board member at the Baltic Sandbox Accelerator. Additionally, he is the CEO of PECON (Consulting) and Thundermountain (VC, Accelerator, Corporate innovation)

An Interdisciplinary Review of Investor Decision-Making in Crowdfunding

A quickly growing body of research is exploring the emerging crowdfunding phenomenon. However, in contrast to traditional startup financing or bank loans, decision-making for investments in crowdfunded ventures is not well researched. Many individual studies investigate aspects that influence investor decision-making in crowdfunding campaigns, but an integrated view of those aspects was not provided to date. We conduct a systematic and interdisciplinary literature review to examine which factors influence investment decision-making in crowdfunding. Based on the analysis of 69 articles we construct a comprehensive framework of relevant influence factors. We elicit systematic differences between crowdfunding and traditional investments, such as venture capital. The differences are: an even higher impact of social capital, the substitution of necessary with available information, and high impact of the digital context. We discuss how information systems (IS) drive those differences. Finally, we derive take-aways for IS researchers and practitioners with focus on interfaces and interactions

HOW CAN DIGITAL START-UPS SUCCESSFULLY RECRUIT IT PROFESSIONALS?

We investigate how digital start-ups can successfully recruit senior IT professionals. This is a challenge, which many young companies face due to their liabilities of newness and smallness but also due to market characteristics such as talent scarcity. We highlight success factors throughout the whole process of senior IT recruiting in a start-up context using an in-depth single case study. Our results suggest that the use of state-of-the-art technology and free choice of hardware are very important recruiting factors. Using multiple platforms to recruit first highly qualified candidates attracts further good talents. Not only typical recruiting platforms are important, but our results show that the use of expert online forums by already employed IT staff can send important signals, strengthen ties with potential candidates, and enable referrals. The recruiting process itself must be fast and interviews should communicate the appraisal of seniority, learning opportunities and management accessibility

Thermally induced subgap features in the cotunneling spectroscopy of a carbon nanotube

We report on nonlinear cotunneling spectroscopy of a carbon nanotube quantum dot coupled to Nb superconducting contacts. Our measurements show rich subgap features in the stability diagram which become more pronounced as the temperature is increased. Applying a transport theory based on the Liouville-von Neumann equation for the density matrix, we show that the transport properties can be attributed to processes involving sequential as well as elastic and inelastic cotunneling of quasiparticles thermally excited across the gap. In particular, we predict thermal replicas of the elastic and inelastic cotunneling peaks, in agreement with our experimental results.Comment: 21 pages, 9 figures, submitted to New Journal of Physic

An interdisciplinary review of investor decision-making in crowdfunding

Abstract: The Dynamic Principal Component Analysis is an adequate tool for the monitoring of large scale systems based on the model of multivariate historical data under the assumption of stationarity, however, false alarms occur for non-stationary new observations during the monitoring phase. In order to reduce the false alarms rate, this paper extends the DPCA based monitoring for non-stationary data of linear dynamic systems, including an on-line means estimator to standardize new observations according to the estimated means. The effectiveness of the proposed methodology is evaluated for fault detection in a interconnected tanks system

Temperature dependence of Andreev spectra in a superconducting carbon nanotube quantum dot

Tunneling spectroscopy of a Nb coupled carbon nanotube quantum dot reveals the formation of pairs of Andreev bound states (ABS) within the superconducting gap. A weak replica of the lower ABS is found, which is generated by quasi-particle tunnelling from the ABS to the Al tunnel probe. An inversion of the ABS-dispersion is observed at elevated temperatures, which signals the thermal occupation of the upper ABS. Our experimental findings are well supported by model calculations based on the superconducting Anderson model.Comment: 6 pages, 7 figure

A systemizing research framework for Web 2.0

Web 2.0 has recently been one of the most discussed topics in Information Systems science and practice. However, little consensus is found on what its components and characteristics actually are and what a comprehensive conceptualization might look like. This paper tries to shed light on these questions by systemizing the phenomenon’s characteristics in a hierarchical framework. In a first step, we apply content and cluster analysis on contributions of the field and inductively identify 103 raw categories which are then clustered into ten subcategories and two main categories. Namely these identified main categories of Web 2.0 are: ‘Technological Characteristics’ and ‘Socioeconomic Characteristics’. In a second step, we pretest and optimize the constructs for applicability and ambiguities and finally apply them to evaluate on the importance and weighting of the discovered subcategories. The resulting framework is found to comply with common quality measures for content analysis and classification schemes. It can be used to analyze and explore economic or social phenomena associated with Web 2.0 in a systematic manner

Building Taxonomies in IS and Management – A Systematic Approach Based on Content Analysis

Classification schemes such as taxonomies are important groundwork for research on many topics in Information Systems (IS) and Management. They make investigating topics manageable by allowing researchers to delimit their work to certain taxa or types and provide a basis for generalization. Opposed to theoretically grounded typologies, taxonomies are empirically derived from entities of a phenomenon under investigation and therefore have several advantages such as more detailed and exhaustive coverage. Nevertheless, research is still missing a clear set of procedures on how to empirically build taxonomies. We tackle this topic by suggesting an inductive approach based on the procedures of content and cluster analysis. Each of the proposed six steps is amended with comprehensive state of the art guidelines, suggestions, alternatives and formative measures of reliability and validity