Why We Read Wikipedia

Wikipedia is one of the most popular sites on the Web, with millions of users relying on it to satisfy a broad range of information needs every day. Although it is crucial to understand what exactly these needs are in order to be able to meet them, little is currently known about why users visit Wikipedia. The goal of this paper is to fill this gap by combining a survey of Wikipedia readers with a log-based analysis of user activity. Based on an initial series of user surveys, we build a taxonomy of Wikipedia use cases along several dimensions, capturing users' motivations to visit Wikipedia, the depth of knowledge they are seeking, and their knowledge of the topic of interest prior to visiting Wikipedia. Then, we quantify the prevalence of these use cases via a large-scale user survey conducted on live Wikipedia with almost 30,000 responses. Our analyses highlight the variety of factors driving users to Wikipedia, such as current events, media coverage of a topic, personal curiosity, work or school assignments, or boredom. Finally, we match survey responses to the respondents' digital traces in Wikipedia's server logs, enabling the discovery of behavioral patterns associated with specific use cases. For instance, we observe long and fast-paced page sequences across topics for users who are bored or exploring randomly, whereas those using Wikipedia for work or school spend more time on individual articles focused on topics such as science. Our findings advance our understanding of reader motivations and behavior on Wikipedia and can have implications for developers aiming to improve Wikipedia's user experience, editors striving to cater to their readers' needs, third-party services (such as search engines) providing access to Wikipedia content, and researchers aiming to build tools such as recommendation engines.Comment: Published in WWW'17; v2 fixes caption of Table

Fluid and Diffusion Limits for Bike Sharing Systems

Bike sharing systems have rapidly developed around the world, and they are served as a promising strategy to improve urban traffic congestion and to decrease polluting gas emissions. So far performance analysis of bike sharing systems always exists many difficulties and challenges under some more general factors. In this paper, a more general large-scale bike sharing system is discussed by means of heavy traffic approximation of multiclass closed queueing networks with non-exponential factors. Based on this, the fluid scaled equations and the diffusion scaled equations are established by means of the numbers of bikes both at the stations and on the roads, respectively. Furthermore, the scaling processes for the numbers of bikes both at the stations and on the roads are proved to converge in distribution to a semimartingale reflecting Brownian motion (SRBM) in a $N^{2}$-dimensional box, and also the fluid and diffusion limit theorems are obtained. Furthermore, performance analysis of the bike sharing system is provided. Thus the results and methodology of this paper provide new highlight in the study of more general large-scale bike sharing systems.Comment: 34 pages, 1 figure

Update of the best practice dietetic management of overweight and obese children and adolescents: a systematic review protocol

To update an existing systematic review series of randomized controlled trials (RCT) that include a dietary intervention for the management of overweight or obesity in children or adolescents.Specifically, the review questions are: In randomized controlled trials of interventions which include a dietary intervention for the management of overweight or obesity in children or adolescents

Impact of weight management nutrition interventions on dietary outcomes in children and adolescents with overweight or obesity: A systematic review with meta-analysis

Background The impact of obesity interventions on dietary intake in children and adolescents with overweight or obesity is unclear. This systematic review aimed to investigate the impact of the dietary component of weight management interventions on the change in diet in children and adolescents with overweight or obesity. Methods Eligible RCTs published between 1975 and 2020 were identified by a systematic search following PRISMA guidelines. Meta-analyses of eligible study outcomes was performed using R statistical software. A multi-level random effects model was used with three significant random effects fitted using Restricted Maximum Likelihood estimation. Results This review identified 109 RCTs, including 95 that reported at least one statistically significant dietary outcome change, and 14 reporting no significant dietary change. Results from the meta-analyses (n= 29 studies) indicated that compared to control groups, intervention groups achieved significantly greater reductions in mean total energy intake at ≤6 months (-194kcal/day, 95%CI -275.80 to -112.90kcal/day, p<0.001) and up to 12 months (-112k cal/ day 95% CI -218.92 to -5.83kcal/ day)p=0.038), increases in fruit and/or vegetable intakes over 2-12 months (n=34, range +0.6 to +1.5 servings/day) and reductions in consumption of sugar-sweetened beverages (n=28, range -0.25 to -1.5 servings/day) at 4-24 months follow-up. Conclusions Obesity interventions with a dietary component have a modest, but sustained impact on reducing total energy intake and improving intakes of specific food groups in children and adolescents with overweight or obesity. High quality RCTs that are powered to detect change in diet as a primary outcome are warranted

Using Cognitive Interviewing for the Semantic Enhancement of Multi-Lingual Versions of Personality Questionnaires

We discuss the use of cognitive interviewing with bilinguals as an integral part of cross-cultural adaptation of personality questionnaires. The aim is to maximize semantic equivalence to increase the likelihood of items maintaining the intended structure and meaning in the target language. We refer to this part of adaptation as semantic enhancement, and integrate cognitive interviewing within it as a tool for scrutinizing translations, the connotative meaning, and the psychological impact of items across languages. During the adaptation of a work-based personality questionnaire from English to Arabic, Chinese (Mandarin), and Spanish, we cognitively interviewed 12 bilingual participants about 136 items in different languages (17% of all items), of which 67 were changed. A content analysis categorizing the reasons for amending items elicited eleven errors that affect two identified forms of semantic equivalence. We provide the resultant coding scheme as a framework for designing cognitive interviewing protocols and propose a procedure for implementing them. We discuss implications for theory and practic

The Radio Observatory on the Lunar Surface for Solar studies

Abstract The Radio Observatory on the Lunar Surface for Solar studies (ROLSS) is a concept for a near-side low radio frequency imaging interferometric array designed to study particle acceleration at the Sun and in the inner heliosphere. The prime science mission is to image the radio emission generated by Type II and III solar radio burst processes with the aim of determining the sites at and mechanisms by which the radiating particles are accelerated. Specific questions to be addressed include the following: (1) Isolating the sites of electron acceleration responsible for Type II and III solar radio bursts during coronal mass ejections (CMEs); and (2) Determining if and the mechanism(s) by which multiple, successive CMEs produce unusually efficient particle acceleration and intense radio emission. Secondary science goals include constraining the density of the lunar ionosphere by searching for a low radio frequency cutoff to solar radio emission and constraining the low energy electron population in astrophysical sources. Key design requirements on ROLSS include the operational frequency and angular resolution. The electron densities in the solar corona and inner heliosphere are such that the relevant emission occurs at frequencies below 10 MHz. Second, resolving the potential sites of particle acceleration requires an instrument with an angular resolution of at least 2°, equivalent to a linear array size of approximately 1000 m. Operations would consist of data acquisition during the lunar day, with regular data downlinks. No operations would occur during lunar night. ROLSS is envisioned as an interferometric array, because a single aperture would be impractically large. The major components of the ROLSS array are 3 antenna arms arranged in a Y shape, with a central electronics package (CEP) located at the center. The Y configuration for the antenna arms both allows for the formation of reasonably high dynamic range images on short time scales as well as relatively easy deployment. Each antenna arm is a linear strip of polyimide film (e.g., Kaptone) on which 16 science antennas are located by depositing a conductor (e.g., silver). The antenna arms can be rolled for transport, with deployment consisting of unrolling the rolls. Each science antenna is a single polarization dipole. The arms also contain transmission lines for carrying the radio signals from the science antennas to the CEP. The CEP itself houses the receivers for the science antennas, the command and data handling hardware, and, mounted externally, the downlink antenna. We have conducted two experiments relevant to the ROLSS concept. First, we deployed a proof-of-concept science antenna. Comparison of the impedance of the antenna feed points with simulations showed a high level of agreement, lending credence to the antenna concept. Second, we exposed a sample of space-qualified polyimide film, with a silver coating on one side, to temperature cycling and UV 2011) 1942-1957 exposure designed to replicate a year on the lunar surface. No degradation of the polyimide film&apos;s material or electric properties was found. Both of these tests support the notion of using polyimide-film based antennas. The prime science mission favors an equatorial site, and a site on the limb could simplify certain aspects of the instrument design. A site on the lunar near side is sufficient for meeting the science goals. While the site should be of relatively low relief topography, the entire site does not have to be flat as the fraction of the area occupied by the antenna arms is relatively small ($0.3%). Further, the antenna arms do not have to lay flat as deviations of ±1 m are still small relative to the observational wavelengths. Deployment could be accomplished either with astronauts, completely robotically, or via a combination of crewed and robotic means. Future work for the ROLSS concept includes more exhaustive testing of the radio frequency (RF) and environmental suitability of polyimide film-based science antennas, ultra-low power electronics in order to minimize the amount of power storage needed, batteries with a larger temperature range for both survival and operation, and rovers (robotic, crewed, or both) for deployment. The ROLSS array could also serve as the precursor to a larger array on the far side of the Moon for astrophysical and cosmological studies

Determinants of health-related quality of life in elderly in Tehran, Iran

BACKGROUND: As Iran started to experience population ageing, it is important to consider and address the elderly people's needs and concerns, which might have direct impacts on their well-being and quality of life. There have been only a few researches into different aspects of life of the elderly population in Iran including their health-related quality of life. The purpose of this study was to measure health-related quality of life (HRQoL) of elderly Iranians and to identify its some determinant factors. METHODS: This was a cross-sectional survey of a random sample of community residents of Tehran aged 65 years old and over. HRQoL was measured using the Short From Health Survey (SF-36). The study participants were interviewed at their homes. Uni-variate analysis was performed for group comparison and logistic regression analysis conducted to predict quality of life determinants. RESULTS: In all, 400 elderly Iranian were interviewed. The majority of the participants were men (56.5%) and almost half of the participants were illiterate (n = 199, 49.8%). Eighty-five percent of the elderly were living with their family or relatives and about 70% were married. Only 12% of participants evaluated their economic status as being good and most of people had moderate or poor economic status. The mean scores for the SF-36 subscales ranged from 70.0 (SD = 25.9) for physical functioning to 53.5 (SD = 29.1) for bodily pain and in general, the respondents significantly showed better condition on mental component of the SF-36 than its physical component (mean scores 63.8 versus 55.0). Performing uni-variate analysis we found that women reported significantly poorer HRQoL. Multiple logistic regression analysis showed that for the physical component summary score of the SF-36, age, gender, education and economic status were significant determinants of poorer physical health-related quality of life; while for the mental component summary score only gender and economic status were significant determinants of poorer mental health-related quality of life. The analysis suggested that the elderly people's economic status was the most significant predictor of their HRQoL. CONCLUSION: The study findings, although with a small number of participants, indicate that elderly people living in Tehran, Iran suffer from relatively poor HRQoL; particularly elderly women and those with lower education. Indeed to improve quality of life among elderly Iranians much more attention should be paid to all aspects of their life including their health, and economic status