Physical and mathematical justification of the numerical Brillouin zone integration of the Boltzmann rate equation by Gaussian smearing

Scatterings of electrons at quasiparticles or photons are very important for many topics in solid state physics, e.g., spintronics, magnonics or photonics, and therefore a correct numerical treatment of these scatterings is very important. For a quantum-mechanical description of these scatterings Fermi's golden rule is used in order to calculate the transition rate from an initial state to a final state in a first-order time-dependent perturbation theory. One can calculate the total transition rate from all initial states to all final states with Boltzmann rate equations involving Brillouin zone integrations. The numerical treatment of these integrations on a finite grid is often done via a replacement of the Dirac delta distribution by a Gaussian. The Dirac delta distribution appears in Fermi's golden rule where it describes the energy conservation among the interacting particles. Since the Dirac delta distribution is a not a function it is not clear from a mathematical point of view that this procedure is justified. We show with physical and mathematical arguments that this numerical procedure is in general correct, and we comment on critical points

Modern Towed Systems: New developments of multipurpose platforms

Towed systems for the inspection of trawl netshave been in use for several decades. Mariscope got into the game with thedevelopment of the Magnus Tow for the German Bundesanstalt für Fischrei inHamburg in 1995. This system used Magnus rotors instead of propellers toposition itself in the trawl net during the trawl. This system was a hybridsince propulsion was used to position the unit at the right place during theoperation within the net. The company has developed a new hybrid system withoutrotors: the Observer III. The first application is a standalone system to beattached inside a trawl net during operation. Here, the position is fixed, butthe system needs to automatically start and stop recording and control thelights and other sensors in order to reduce power consumption.Fil: Haag, Christian. Mariscope Meerestechnik; AlemaniaFil: Dreyschultze, Christian. Mariscope Meerestechnik; AlemaniaFil: González, Raul Alberto Candido. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentin

Svendy Wittmann / Thomas Rauschenbach / Hans Rudolf Leu (Hrsg.): Kinder in Deutschland. Eine Bilanz empirischer Studien. Weinheim / München: Juventa 2011 (308 S.) [Rezension]

Rezension von: Svendy Wittmann / Thomas Rauschenbach / Hans Rudolf Leu (Hrsg.): Kinder in Deutschland. Eine Bilanz empirischer Studien. Weinheim / München: Juventa 2011 (308 S.; ISBN 978-3-7799-2240-7; 26,00 EUR)

Adjusting to the Survey: How Interviewer Experience Relates to Interview Duration

Interview duration has been shown to become shorter as fieldwork progresses. This has been attributed to a learning effect interviewers go through as they gather experience. In this study, we expand on this knowledge by focusing on how two kinds of interviewer experience relate to interview duration in telephone surveys. Using data from the German National Educational Panel Study (NEPS), we employ multilevel models, accounting for the clustering of respondents within interviewers. The results strengthen previous findings associating within-survey interviewer experience with decreasing interview duration. On the other hand, countering previous work, we find evidence that interview duration also decreases with overall interviewer experience. The results add to our knowledge concerning the effect of interviewer experience in the telephone survey mode. The effects are robust to several model specifications and to different interviewer, respondent, and interview characteristics. We conclude with a discussion about how to manage interviewer experience during training and fieldwork

Kinderwunsch und Vaterschaftspläne homosexueller Männer: erste Ergebnisse der ifb-Studie "Gleichgeschlechtliche Lebensweisen in Deutschland"

Inhaltsverzeichnis: 1 Einleitung; 2 Strukturelle Entwicklungen; 2.1 Globalisierungseinflüsse; 2.2 Individualisierte Lebensverläufe; 3 Entwicklung der Rahmenbedingungen gleichgeschlechtlicher Lebensweisen; 3.1 Pluralisierung von Familien- und Lebensformen; 3.2 Gleichgeschlechtliche Lebensweisen in Deutschland; 4 KINDERWUNSCH; 4.1 Konzept "Kinderwunsch"; 4.2 Männlicher Kinderwunsch; 4.3 Kinderwunsch homosexueller Männer; 5 Entwicklung der Forschungsfrage und Hypothesen; 6 Methodik; 6.1 Instrument; 6.2 Zugang; 6.3 Stichprobe; 7 Ergebnisse der Befragung; 7.1 Soziodemographie der Befragten; 7.2 Die Bedeutung von Kindern; 7.3 Kinderwunsch homosexueller Männer; 7.4 Begründungen negativen Kinderwunsches; 7.5 Kinderwunschmotive – Value of Children (VoC); 7.6 Einflussfaktoren auf den Kinderwunsch; 7.7 Voraussetzungen zur Verwirklichung; 7.8 Vorstellungen von der Verwirklichung; 7.9 Verwirklichung in Angriff genommen; 7.10 Zusammenfassung der Ergebnisse und Hypothesenprüfung

Emergence of a new type of family? Parenting intentions of homosexual women and men

Christian Haag holds a diploma degree in Sociology from the University of Bamberg and also studied at the National University of Ireland in Galway. He has taught and researched at the chair of Sociology I at the University of Bamberg, at the State Institute for Family Research at the University of Bamberg (ifb), and at the Goethe University Frankfurt. His work is focussed on social inequality, life course research, and family sociology. Specialties include employment of women and mothers, reconciliation of family and employment, same-sex relationships and homosexuality, attitudes towards the family and normative images of the family, and parenting intentions, particularly in the context of artificial reproductive techniques. In his dissertation, Christian Haag contributes to the body of research in family sociology in providing original results on parenting intentions of homosexual women and men. Based on a quantitative German dataset from the State Institute for Family Research at the University of Bamberg (ifb), the thesis delineates parenting intentions, finds evidence for influencing factors which are important in the development of these intentions, and furthermore describes and discusses intended family patterns of homosexual women and men. The implications are discussed at an individual and a societal level. Results throughout point towards the importance of the social and legal framework. Results and their implications extend to common issues and topics for all couples in treatment with assisted reproductive techniques

Research Agenda on Families and Family Wellbeing for Europe

This report is the final outcome of FAMILYPLATFORM and the result of the encounter between more than 170 experts and stakeholders from all over Europe and beyond, creating a lively think tank on family issues. It summarises important policy questions, research gaps and research issues that were highlighted during the 18 months of working together closely within FAMILYPLATFORM. A series of societal challenges for families, family‐related policy and research have been identified through the work of FAMILYPLATFORM. Based on these crucial societal challenges, seven important research areas are outlined in this report: 1. Family Policy, 2. Care, 3. Life Course and Transitions, 4. Doing Family, 5. Migration and Mobility, 6. Inequalities and Insecurities, 7. Media and New Information Technologies. In each research area vital research questions are identified, combined with general remarks on methodological issues and approaches. Altogether, these challenges, research areas and methodological issues are building a research roadmap for the European Union for the years ahead. The realisation of this research roadmap could help policy makers to meet future societal challenges and to improve the wellbeing of families