Experimental evaluation of outer planets probe thermal insulation concepts

An experimental program was conducted to evaluate various thermal insulation concepts for use in the Outer Planets Probe (OPP) during entry and descent into the atmospheres of Jupiter, Saturn, and Uranus. Phenolic fiberglass honeycomb specimens representative of the OPP structure were packed and tested with various fillers: Thermal conductivity measurements were made over a temperature range of 300 K to 483 K and pressures from vacuum up to 10 atmospheres in helium and nitrogen gas environments. The conductivity results could not be fully explained so new test specimens were designed with improved venting characteristics, and tested to determine the validity of the original data. All of the conductivity data showed results that were substantially higher than expected. The original test data in helium were lower than the data from the redesigned specimens, probably due to inadequate venting of nitrogen gas from the original specimens. The thermal conductivity test results show only a marginal improvement in probe thermal protection performance for a filled honeycomb core compared to an unfilled core. In addition, flatwise tension tests showed a severe bond strength degradation due to the inclusion of either the powder or foam fillers. In view of these results, it is recommended that the baseline OPP design utilize an unfilled core

Dream team or nightmare? Collaboration in project teams

Project teams are a contemporary organizing principle. They work on non-routine tasks. Team composition in project teams is often interdisciplinary (i.e., uniting team members from different departments or areas of expertise within an organization). Project teams face a number of challenges. In particular, collaborative task accomplishment is often accompanied by conflict in project teams. This chapter describes the specific challenges in project teams and showcases different approaches for conflict management and team development in project teams

"Das schnelle Date". Internetgestützte Sexkontakte und HIV-Infektionsrisiko. Ergebnisse einer 2006 durchgeführten Internetbefragung

Der seit Ende der 1990er Jahre diskutierten Frage, ob bei Sexualkontakten, die über Kontaktseiten im Internet hergestellt werden, in geringerem Umfang präventive Vorkehrungen in Hinblick auf HIV-Übertragungen erfolgen als bei andernorts angebahnten Kontakten, sollte in einer im Frühjahr 2006 durchgeführten Online-Umfrage nachgegangen werden. Die Umfrage erfolgte über vier Dating-Portale für heterosexuelle Frauen und Männer und über vier Portale für homound bisexuelle Männer. Von den berücksichtigten 5.050 Fragebögen entfielen 76 Prozent auf Männer, die ausschließlich gleichgeschlechtliche Sexualkontakte in den 12 Monaten vor der Befragung angaben, 11 Prozent der Männer wurden aufgrund ihrer Angaben als bisexuell und weitere 11 Prozent als heterosexuell definiert. Frauen stellten lediglich 2 Prozent der BefragungsteilnehmerInnen. Etwa drei Viertel aller Befragten schätzten an Kontaktseiten, das sie darüber Menschen „mit gleichen Vorlieben“ kennenlernen können, dabei muss es sich nicht um sexuelle Vorlieben handeln: So haben etwa 22 Prozent der Frauen, 12 Prozent der homosexuellen, 9 Prozent der heterosexuellen und 6 Prozent der bisexuellen Männer überhaupt keine(n) Sexpartner(in) in den 12 Monaten vor der Befragung gesucht. Online gesucht aber keine(n) Partner(in) gefunden haben 18 Prozent der Frauen, 21 Prozent der homosexuellen, 24 Prozent der bisexuellen und 45 Prozent der heterosexuellen Männer. Etwa die Hälfte der homo- und bisexuellen Männer haben ihre SexualpartnerInnen mehrheitlich oder ausschließlich über das Internet kennengelernt, während dies nur auf 39 Prozent der heterosexuellen Männer zutrifft (zwei Drittel geben dies in der kleinen Gruppe der Frauen an). Dass heterosexuelle Männer die geringsten Erfolge beim Anbahnen von Sexualkontakten über das Internet haben, zeigen auch andere erhobene Daten. Unter den Befragungsteilnehmern erfolgte regelmäßiger Kondomgebrauch bei Vaginal- oder Analverkehr – je nach Gruppenzugehörigkeit - zu sehr unterschiedlichen Anteilen. 55 Prozent der homosexuellen und 47 Prozent der bisexuellen Männer benutzten grundsätzlich Kondome, 38 Prozent der heterosexuellen Männer und 34 Prozent der Frauen gaben dies an. Hinsichtlich des Risikos, sich mit HIV zu infizieren (ungeschützter Anal- oder Vaginalverkehr mit PartnerInnen mit unbekanntem oder diskordantem Serostatus - Expositionsrisiko), bestanden nur geringe Unterschiede zwischen homo- (27%), bi- (31%) und heterosexuellen Männern (26%) bzw. Frauen (27%). Ein Transmissionsrisiko konnte lediglich in der Teilgruppe der homosexuellen (8%) und bisexuellen (1%) Männer festgestellt werden, da in den anderen beiden Gruppen niemand HIV-positiv war. Es zeigt sich, dass bei der überwiegenden Mehrheit aller Befragten das HIV-bezogene sexuelle Risikoverhalten bei online- und offline-Dates gleich ist. Are people more likely to risk an HIV infection with sex partners they meet online as compared to those whom they meet offline? This question has been the subject of research since the late 1990s in several post-industrialized countries. This paper presents the results of a study conducted in Germany in 2006. A link to an anonymous, self-administered online questionnaire was posted on four dating websites for heterosexual men and women and on four dating websites for men who have sex with men. Of the 5,050 respondents included in the analysis, 76 per cent were men who reported sexual contacts in the previous twelve months exclusively with other men; 11 per cent could be classified as bisexual men (sexual contacts with men and women), and 11 per cent as heterosexual men (sexual contact with women only).. Two per cent of all respondents were women; because of the small number of respondents this group was not further stratified in the analysis. Finding persons “with similar interests” was the most frequently expressed positive aspect of dating websites (78% among homosexual men, 80% among bisexual men, 74% among heterosexual men, and 73% among women). This did not necessarily mean similar sexual interests: 22 per cent of the women, 12 per cent of the homosexual men, 6 per cent of the bisexual men, and 9 per cent of the heterosexual men claimed they had not been looking for sex partners during their visits to the sites in the previous twelve months. Many respondents reported being unsuccessful in finding a sex partner online: 18 per cent of the women, 21 per cent of the homosexual men, 24 per cent of the bisexual men, and 45 per cent of the heterosexual men. While during the previous twelve months half of the homo- and bisexual men found most (if not all) of their sex partners on the Internet, the respective proportions were 39 per cent among heterosexual men, and 67% in the small group of female respondents. Taken together, heterosexual men were the least successful in finding sex partners on the Internet. Regular use of condoms for every anal or vaginal intercourse was reported by 55 per cent of the homosexual men, 47 per cent of the bisexual men, 38 of the heterosexual men, and 34 per cent of the women. However, regarding unprotected anal or vaginal intercourse with a sex partner of unknown or discordant HIV serostatus, the proportions among the different subgroups were very similar (homosexual men: 27%; bisexual men: 31%; heterosexual men: 26%; women: 27%). The risk of transmitting a known HIV infection to sex partners was only present among homosexual (8%) and bisexual (1%) men, primarily because only respondents from these two subgroups identified as HIV-positive. For the large majority (83-86%) of men, HIV risk behaviours are the same, regardless if sex partners are met online or offline

Evidence of English language proficiency and academic achievement of non-English-speaking background students

The increasing number of international students enrolled in Australian universities over the last decade has met with a corresponding concern that many non-English-speaking background (NESB) students experience considerable difficulty in their courses. Consequently, concerns about admission procedures have been raised regarding how English language proficiency (ELP) is determined for NESB students (both domestic and international). In addition to standardised ELP tests, some universities accept other forms of evidence, such as the completion of English-medium courses. This large-scale quantitative study analysed data on 5675 undergraduate and postgraduate students available from one university's database over a three-year period to ascertain if its ELP requirements were sufficient to ensure the academic progress of adequate numbers of these students. The best evidence for potential academic success was found to be standardised tests while students submitting other forms of ELP evidence tended to have more difficulties

The upgrade of GEO600

The German / British gravitational wave detector GEO 600 is in the process of being upgraded. The upgrading process of GEO 600, called GEO-HF, will concentrate on the improvement of the sensitivity for high frequency signals and the demonstration of advanced technologies. In the years 2009 to 2011 the detector will undergo a series of upgrade steps, which are described in this paper.Comment: 9 pages, Amaldi 8 conference contributio

Optimal Alignment Sensing of a Readout Mode Cleaner Cavity

Critically coupled resonant optical cavities are often used as mode cleaners in optical systems to improve the signal to noise ratio (SNR) of a signal that is encoded as an amplitude modulation of a laser beam. Achieving the best SNR requires maintaining the alignment of the mode cleaner relative to the laser beam on which the signal is encoded. An automatic alignment system which is primarily sensitive to the carrier field component of the beam will not, in general, provide optimal SNR. We present an approach that modifies traditional dither alignment sensing by applying a large amplitude modulation on the signal field, thereby producing error signals that are sensitive to the signal sideband field alignment. When used in conjunction with alignment actuators, this approach can improve the detected SNR; we demonstrate a factor of 3 improvement in the SNR of a kilometer-scale detector of the Laser Interferometer Gravitational-wave Observatory. This approach can be generalized to other types of alignment sensors

Beyond ‘ignorance’: using the cultural stereotypes of Americans studying in the UK as a resource for learning and teaching about British culture

A course introducing British culture is a standard component of many study abroad programmes running in this country that are aimed at international students who will be spending a limited amount of time in the United Kingdom. However, it is not often acknowledged that such students possess a range of strong pre-conceptions about British culture and society prior to their arrival. Conventional teaching strategies assume student ignorance of the subject. However, an alternative approach which makes us of pre-arrival stereotypes can be more productive in terms of engaging students in active processes of comparative analysis of their new and existing knowledge. A case study of American student stereotypes of the British monarchy is presented and it is suggested that these can be used as the basis for refining student understanding of cultural politics in the United Kingdom. International students, therefore, should not be treated as being culturally ignorant of Britain in the sense of having no knowledge or opinions at all. Rather, it should be understood that they possess a culturally mediated state of subjectivity which I refer to as ‘ignorance’ and that this can become a valuable resource for teaching and learning

ABAEnrichment: An R package to test for gene set expression enrichment in the adult and developing human brain

Summary: We present ABAEnrichment, an R package that tests for expression enrichment in specific brain regions at different developmental stages using expression information gathered from multiple regions of the adult and developing human brain, together with ontologically organized structural information about the brain, both provided by the Allen Brain Atlas. We validate ABAEnrichment by successfully recovering the origin of gene sets identified in specific brain cell-types and developmental stages. Availability and Implementation: ABAEnrichment was implemented as an R package and is available under GPL (≥ 2) from the Bioconductor website (http://bioconductor.org/packages/3.3/bioc/html/ABAEnrichment.html). Contacts: [email protected], [email protected] or [email protected] Supplementary information: Supplementary data are available at Bioinformatics online