A scientific operations plan for the NASA space telescope

A ground system is described which is compatible with the operational requirements of the space telescope. The goal of the ground system is to minimize the cost of post launch operations without seriously compromising the quality and total throughput of space telescope science, or jeopardizing the safety of the space telescope in orbit. The resulting system is able to accomplish this goal through optimum use of existing and planned resources and institutional facilities. Cost is also reduced and efficiency in operation increased by drawing on existing experience in interfacing guest astronomers with spacecraft as well as mission control experience obtained in the operation of present astronomical spacecraft

Spartan Release Engagement Mechanism (REM) stress and fracture analysis

The revised stress and fracture analysis of the Spartan REM hardware for current load conditions and mass properties is presented. The stress analysis was performed using a NASTRAN math model of the Spartan REM adapter, base, and payload. Appendix A contains the material properties, loads, and stress analysis of the hardware. The computer output and model description are in Appendix B. Factors of safety used in the stress analysis were 1.4 on tested items and 2.0 on all other items. Fracture analysis of the items considered fracture critical was accomplished using the MSFC Crack Growth Analysis code. Loads and stresses were obtaind from the stress analysis. The fracture analysis notes are located in Appendix A and the computer output in Appendix B. All items analyzed met design and fracture criteria

Materials properties, loads, and stress analysis, Spartan REM: Appendix A

The mechanical properties, load tests, and stress analysis of the Spartan Release Engagement Mechanism (REM) is presented. The fracture properties of the components of the unit are also discussed. Detailed engineering drawings are included

A New Massive Type IIA Supergravity From Compactification

We consider the most general form for eleven dimensional supersymmetry compatible with on-shell superfields. This allows for the introduction of a conformal Spin(1,10) connection. In eleven dimensional Minkowski space this modification is trivial and can be removed by a field redefinition, however, upon compactification on S^1 it is possible to introduce a non-trivial `Wilson line'. The resulting ten dimensional supergravity has massive 1-form and 3-form potentials and a cosmological constant. This theory does not possess a supersymmetric eightbrane soliton but it does admit a supersymmetric non-static cosmological solution.Comment: 13 pages, phyzzx. The introduction is clarifed and a reference adde

The Threebrane Soliton of the M-Fivebrane

We discuss the supersymmetry algebra of the M theory fivebrane and obtain a new threebrane soliton preserving half of the six-dimensional supersymmetry. This solution is dimensionally reduced to various D-p-branes.Comment: 10 pages, phyzz

Mining Missing Hyperlinks from Human Navigation Traces: A Case Study of Wikipedia

Hyperlinks are an essential feature of the World Wide Web. They are especially important for online encyclopedias such as Wikipedia: an article can often only be understood in the context of related articles, and hyperlinks make it easy to explore this context. But important links are often missing, and several methods have been proposed to alleviate this problem by learning a linking model based on the structure of the existing links. Here we propose a novel approach to identifying missing links in Wikipedia. We build on the fact that the ultimate purpose of Wikipedia links is to aid navigation. Rather than merely suggesting new links that are in tune with the structure of existing links, our method finds missing links that would immediately enhance Wikipedia's navigability. We leverage data sets of navigation paths collected through a Wikipedia-based human-computation game in which users must find a short path from a start to a target article by only clicking links encountered along the way. We harness human navigational traces to identify a set of candidates for missing links and then rank these candidates. Experiments show that our procedure identifies missing links of high quality

Emergency braking for free piston energy converters

Free piston energy converters are a potential technology for future hybrid vehicles, as well as stationary power generation applications. A candidate 2-stroke system comprises of two opposing combustion chambers with a common piston rod, and integrated with a tubular permanent magnet electrical machine for the conversion of mechanical to electrical energy. A key issue for the ultimate adoption of such systems, however, is their robustness in the event of a fault to enable a safe shutdown, with minimal mechanical or electrical damage. The paper considers system braking issues and the importance of early fault detection. Results are presented to demonstrate the effectiveness of passive and active braking techniques for a range of dc-link supply voltage and operating output power

A Mobile App to Aid Smoking Cessation: Preliminary Evaluation of SmokeFree28

Background: Little is known about the effectiveness of mobile apps in aiding smoking cessation or their validity for automated collection of data on smoking cessation outcomes. Objective: We conducted a preliminary evaluation of SF28 (SF28 is the name of the app, short for SmokeFree28)—an app aimed at helping smokers to be smoke-free for 28 days. / Methods: Data on sociodemographic characteristics, smoking history, number of logins, and abstinence at each login were uploaded to a server from SF28 between August 2012 and August 2013. Users were included if they were aged 16 years or over, smoked cigarettes at the time of registration, had set a quit date, and used the app at least once on or after their quit date. Their characteristics were compared with data from a representative sample of smokers trying to stop smoking in England. The percentage of users recording 28 days of abstinence was compared with a value of 15% estimated for unaided quitting. Correlations were assessed between recorded abstinence for 28 days and well-established abstinence predictors. / Results: A total of 1170 users met the inclusion criteria. Compared with smokers trying to quit in England, they had higher consumption, and were younger, more likely to be female, and had a non-manual rather than manual occupation. In total, 18.9% (95% CI 16.7-21.1) were recorded as being abstinent from smoking for 28 days or longer. The mean number of logins was 8.5 (SD 9.0). The proportion recording abstinence for 28 days or longer was higher in users who were older, in a non-manual occupation, and in those using a smoking cessation medication. / Conclusions: The recorded 28-day abstinence rates from the mobile app, SF28, suggest that it may help some smokers to stop smoking. Further evaluation by means of a randomized trial appears to be warranted

Identification of behaviour change techniques and engagement strategies to design a smartphone app to reduce alcohol consumption using a formal consensus method

Background: Digital interventions to reduce excessive alcohol consumption have the potential to have a broader reach and be more cost-effective than traditional brief interventions. However, there is not yet a strong evidence base on their ability to engage users or on their effectiveness. Objective: This study aimed to identify the behaviour change techniques (BCTs) and engagement strategies most worthy of further study by inclusion in a smartphone application (app) to reduce alcohol consumption, using formal expert consensus methods. Methods: The first phase of the study consisted of a Delphi exercise with three rounds. It was conducted with seven international experts in the field of alcohol and/or behaviour change. In the first round, experts identified BCTs most likely to be effective at reducing alcohol consumption and strategies most likely to engage users with an app; these were rated in the second round; and those rated as effective by at least four out of seven participants were ranked in the third round. The rankings were analysed using Kendall’s W coefficient of concordance, which indicates consensus between participants. The second phase consisted of a new, independent group of experts (n=43) ranking the BCTs that were identified in the first phase. The correlation between the rankings of the two groups was assessed using Spearman’s rank correlation coefficient. Results: Twelve BCTs were identified as likely to be effective. There was moderate agreement among the experts over their ranking (W=.465, χ2(11)=35.77, P<.001) and the BCTs receiving the highest mean rankings were self-monitoring, goal-setting, action planning, and feedback in relation to goals. There was a significant correlation between the ranking of the BCTs by the group of experts who identified them and a second independent group of experts (Spearman’s rho=.690, P=.01). Seventeen responses were generated for strategies likely to engage users. There was moderate agreement among experts on the ranking of these engagement strategies (W=.563, χ2(15)=59.16, P<.001) and those with the highest mean rankings were ease of use, design – aesthetic, feedback, function, design – ability to change design to suit own preferences, tailored information, and unique smartphone features. Conclusions: The BCTs with greatest potential to include in a smartphone app to reduce alcohol consumption were judged by experts to be self-monitoring, goal-setting, action planning, and feedback in relation to goals. The strategies most likely to engage users were ease of use, design, tailoring of design and information, and unique smartphone features