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

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

A Modified Stern-Gerlach Experiment Using a Quantum Two-State Magnetic Field

The Stern-Gerlach experiment has played an important role in our understanding of quantum behavior. We propose and analyze a modified version of this experiment where the magnetic field of the detector is in a quantum superposition, which may be experimentally realized using a superconducting flux qubit. We show that if incident spin-$1/2$ particles couple with the two-state magnetic field, a discrete target distribution results that resembles the distribution in the classical Stern-Gerlach experiment. As an application of the general result, we compute the distribution for a square waveform of the incident fermion. This experimental setup allows us to establish: (1) the quantization of the intrinsic angular momentum of a spin-$1/2$ particle, and (2) a correlation between EPR pairs leading to nonlocality, without necessarily collapsing the particle's spin wavefunction.Comment: 12 pages, 2 figure

Actively Tuned and Spatially Trapped Polaritons

We report active tuning of the polariton resonance of quantum well excitons in a semiconductor microcavity using applied stress. Starting with the quantum well exciton energy higher than the cavity photon mode, we use stress to reduce the exciton energy and bring it into resonance with the photon mode. At the point of zero detuning, line narrowing and strong increase of the photoluminescence are seen. By the same means, we create an in-plane harmonic potential for the polaritons, which allows trapping, potentially making Bose-Einstein condensation of polaritons analogous to trapped atoms possible. We demonstrate drift of the polaritons into this trap.Comment: 10 pages, 5 figure

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

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

Cometary Astrometry

Modern techniques for making cometary astrometric observations, reducing these observations, using accurate reference star catalogs, and computing precise orbits and ephemerides are discussed in detail and recommendations and suggestions are given in each area

Genetic stratigraphy of the Fort Scott Limestone (Pennsylvanian, Desmoinesian), southeastern Kansas

The punctuated aggradational cycle (PAC) approach of Anderson and Goodwin (1980) and transgressive-regressive units of Busch and Rollins (1984) were used to differentiate small-scale [1-3 m (3.3-10 ft) thick] genetic units in strata of the 9+-m-thick (30+-ft-thick) Fort Scott Limestone (Marmaton Group, Desmoinesian Stage, Middle Pennsylvanian Series) of southeastern Kansas, northeastern Oklahoma, and west-central Missouri. Nine outcrop exposures were observed directly, and information from 20 stratigraphic sections was taken from the literature. The lithologic sequence of the Marmaton Group is similar to cyclothems of the Illinois basin, and thus the genesis of coal is important. Many recent studies have interpreted midcontinent sedimentary strata using Heckel's (1977) model of the basic Kansas cyclothem, which emphasizes a lithostratigraphic approach. The PAC hypothesis is a genetic approach that provides a chronostratigraphic framework for interpreting the strata, reveals a more detailed sea-level history compared to the cyclothem approach, and provides more details for inferring the paleotopography, structural controls, paleogeography and paleoclimatology of the interval. We have identified four (possibly five) sixth-order cycles (Brett et al., 1990) or PACs (Goodwin and Anderson, 1985), which include as many flooding surfaces, in an interval previously interpreted as one cyclothem [the upper Fort Scott cyclothem of Knight (1985)]. These PACs can be traced and correlated throughout the outcrop area, a distance of over 300 km (190 mi), and are similar to small-scale cycles recognized by others in the Triassic of Italy and in the Silurian-Devonian sequence of New York. Recognition and correlation of sixth-order cycles (Brett et al., 1990) or PACs is of value to sedimentary modelers because the more detailed relative sea-level curves and finer scale stratigraphic details will result in better defined parameters, such as sedimentation rates, magnitudes of sea-level changes, and climatic perturbations

Influencing the physiology and decisions of groups: Physiological linkage during group decision-making

Many of the most important decisions in our society are made within groups, yet we know little about how the physiological responses of group members predict the decisions that groups make. In the current work, we examine whether physiological linkage from “senders” to “receivers”—which occurs when a sender’s physiological response predicts a receiver’s physiological response—is associated with senders’ success at persuading the group to make a decision in their favor. We also examine whether experimentally manipulated status—an important predictor of social behavior—is associated with physiological linkage. In groups of 5, we randomly assigned 1 person to be high status, 1 low status, and 3 middle status. Groups completed a collaborative decision-making task that required them to come to a consensus on a decision to hire 1 of 5 firms. Unbeknownst to the 3 middle-status members, high- and low-status members surreptitiously were told to each argue for different firms. We measured cardiac interbeat intervals of all group members throughout the decision-making process to assess physiological linkage. We found that the more receivers were physiologically linked to senders, the more likely groups were to make a decision in favor of the senders. We did not find that people were physiologically linked to their group members as a function of their fellow group members’ status. This work identifies physiological linkage as a novel correlate of persuasion and highlights the need to understand the relationship between group members’ physiological responses during group decision-making