Causal inference for continuous-time processes when covariates are observed only at discrete times

Most of the work on the structural nested model and g-estimation for causal inference in longitudinal data assumes a discrete-time underlying data generating process. However, in some observational studies, it is more reasonable to assume that the data are generated from a continuous-time process and are only observable at discrete time points. When these circumstances arise, the sequential randomization assumption in the observed discrete-time data, which is essential in justifying discrete-time g-estimation, may not be reasonable. Under a deterministic model, we discuss other useful assumptions that guarantee the consistency of discrete-time g-estimation. In more general cases, when those assumptions are violated, we propose a controlling-the-future method that performs at least as well as g-estimation in most scenarios and which provides consistent estimation in some cases where g-estimation is severely inconsistent. We apply the methods discussed in this paper to simulated data, as well as to a data set collected following a massive flood in Bangladesh, estimating the effect of diarrhea on children's height. Results from different methods are compared in both simulation and the real application.Comment: Published in at http://dx.doi.org/10.1214/10-AOS830 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Associated Charmonium Production in p-pbar Annihilation

In this paper we summarize our recent results for low energy associated charmonium production cross sections, using 1) crossing symmetry, and 2) an explicit hadronic model. These predictions are of relevance to the planned charmonium and charmonium hybrid production experiment PANDA at GSI.Comment: 5 pages, 5 figures. Contribution to the Second Meeting of the APS Topical Group on Hadron Physics GHP2006. (Nashville, TN, 22-24 Oct. 2006

Do dictionary users really look up frequent words? — on the overestimation of the value of corpus-based lexicography

An innovative online Swahili–English dictionary project is presented. A careful study of some of the log files attached to this reference work reveals some hitherto unknown as-pects of true dictionary look-up behaviour, which results in the depreciation of the importance of corpora for dictionary making. Three lexicography software modules are advanced to further enhance the success of the online dictionary. Keywords: lexicography, software, online, dictionary, log file, corpus, frequency, rank, correlation, swahili, english, tshwanele

Young Adults' Experience of Loneliness in London's Most Deprived Areas

Young adults (16-24 years old) are currently the loneliest group in Western countries. In particular, young adults of lower socio-economic status (SES) living in the most deprived areas are loneliest in the United Kingdom. This mixed-methods study explored the experience of loneliness among this under-explored demographic in London. Using a novel free association technique, the experience of loneliness was found to be characterized by: a sense of isolation, negative emotions and thoughts, coping and a positive orientation to aloneness. An exploration of these themes revealed that: one can feel isolated or excluded even when surrounded by people; the experience of loneliness is accompanied by a set of interrelated feelings and thoughts like rumination; and technological and/or non-technological outlets can be used to cope. Social media play both a positive and negative role in loneliness, and loneliness is not always experienced negatively. The quantitative data indicated that this sample was lonely. By providing insight into young adults' loneliness, the findings indicate what types of interventions are likely to diminish it

School mathematics and dyslexia: aspects of the interrelationship

This investigation sought to explore the nature and extent of school mathematical difficulties among the dyslexic population. Anecdotal reports have suggested that many dyslexics may have difficulties in arithmetic, but few systematic studies have previously been undertaken. The literature pertaining to dyslexia and school mathematics respectively is reviewed. Clues are sought in studies of dyscalculia. These seem inadequate in accounting for dyslexics' reported mathematical difficulties. Similarities between aspects of language and mathematics are examined for underlying commonalities that may partially account for concomitant problems in mathematics, in individuals with a written language dysfunction. The performance of children taught using different mathematics work-schemes is assessed to ascertain if these are associated with differential levels of achievement that may be reflected in the dyslexic population few are found. Findings from studies designed to assess the relationship between written language failure and achievement in mathematics are reported. Study 1 reveals large correlational differences between subtest scores (Wechsler Intelligence Scale for Children, Wechsler, 1976) and three mathematics tests, for young dyslexics and children without literacy difficulties. However, few differences are found between levels of attainment, at this age (6 ½ - 9 years). Further studies indicate that, for dyslexics, achievement in school mathematics, may be independent of measured intelligence, as is the case with their literacy skills. Studies 3 and 4 reveal that dyslexics' performances on a range of school mathematical topics gets relatively worse compared with that of Controls (age range 8 - 17 years), as they get older. Extensive item analyses reveal many errors relating strongly to known deficits in the dyslexics' learning style - poor short-term memory, sequencing skills and verbal labelling strategies. Subgroups of dyslexics are identified on the basis of mathematical performance. Tentative explanations, involving alternative neuropsychological approaches, are offered for the measured differences in attainment between these groups

Position related differences in physiological measures of collegiate rugby union players

Position related differences have previously been identified in elite rugby union players however similar research into non-elite rugby union players is limited. The purpose of this study was to investigate the differences due to playing position in physiological measures of collegiate rugby union players

Wellbeing in the city: Young adults' sense of loneliness and social connection in deprived urban neighbourhoods

Neighbourhood characteristics can facilitate or hinder the development of social ties, thereby influencing the loneliness of those who live in them. Most research to date has focused upon how either older adults (65+) or youth (under 19 years old) view and experience their neighbourhood, paying little attention to young adults (aged 16–24). Young adults are the loneliest age-group within the UK and other Western countries. Their loneliness is associated with living in deprived communities (e.g., areas experiencing social-economic inequalities), feeling a strong sense of disconnection from their neighbourhoods and having little trust in others within these spaces. Therefore, this study utilises social representations theory to explore how young adults (18–24 years old) from London's four most deprived boroughs view and experience their neighbourhood using a systematic, qualitative methodology. In particular, the concept of dialogical antimonies, known as themata are used. A purposive sample of forty-eight participants was asked to write and/or draw where they felt loneliest and where they felt most socially connected in their neighbourhoods. These associations were then explored via an open-ended, exploratory interview. This revealed that the experience of neighbourhood was structured around four themata: 1) having no one to talk to/being disconnected from others vs. being with family or friends, 2) feeling bored/having nothing to do vs. having shared interests, goals or activities, 3) being in an unfamiliar environment vs. seeing familiar faces/having a sense of community, 4) busy vs. peaceful environment. On this basis, suggestions and implications for the design of wellbeing-enhancing neighbourhoods are discussed

How young adults cope with loneliness: a study of London’s most deprived boroughs

There is growing recognition that young adults of low socioeconomic status are among the loneliest in the United Kingdom. However, there has been a dearth of qualitative research exploring how they cope with their loneliness. Using a novel free association technique, this study sought to explore how young adults (n = 48) in London’s most deprived areas cope with feeling lonely. A thematic analysis, informed by an inductive approach, identified six key themes. Seeking connection, avoidance, seeking support and cognitive strategies were most prevalent. Meaning-focused coping and distraction were also identified, albeit less often. Overall, there were diverse ways of coping within and across respondents and important differences were found between the genders. The findings call for the early identification of those at risk of persistent avoidance behaviours and for interventions that provide meaningful leisure activities, with mutual goals in communities, alongside the strengthening of support and authenticity in relationships

Measurement of the τ Lepton Polarization and R(D^{*}) in the Decay B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ}

We report the first measurement of the τ lepton polarization Pτ (D ∗ ) in the decay B¯ → D ∗ τ −ν¯τ as well as a new measurement of the ratio of the branching fractions R(D ∗ ) = B(B¯ → D ∗ τ −ν¯τ )/B(B¯ → D ∗ ` −ν¯`), where ` − denotes an electron or a muon, and the τ is reconstructed in the modes τ − → π −ντ and τ − → ρ −ντ . We use the full data sample of 772×106 BB¯ pairs recorded with the Belle detector at the KEKB electron-positron collider. Our results, Pτ (D ∗ ) = −0.38±0.51(stat.) +0.21 −0.16(syst.) and R(D ∗ ) = 0.270 ± 0.035(stat.) +0.028 −0.025(syst.), are consistent with the theoretical predictions of the Standard Model