Multiplicity Distributions and Charged-neutral Fluctuations

Results from the multiplicity distributions of inclusive photons and charged particles, scaling of particle multiplicities, event-by-event multiplicity fluctuations, and charged-neutral fluctuations in 158$\cdot A$ GeV Pb+Pb collisions are presented and discussed. A scaling of charged particle multiplicity as $N_{part}^{1.07\pm 0.05}$ and photons as $N_{part}^{1.12\pm 0.03}$ have been observed, indicating violation of naive wounded nucleon model. The analysis of localized charged-neutral fluctuation indicates a model-independent demonstration of non-statistical fluctuations in both charged particles and photons in limited azimuthal regions. However, no correlated charged-neutral fluctuations are observed.Comment: Talk given at the International Symposium on Nuclear Physics (ISNP-2000), Mumbai, India, 18-22 Dec 2000, Proceedings to be published in Pramana, Journal of Physic

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Statistical modelling of key variables in social survey data analysis

The application of statistical modelling techniques has become a cornerstone of analyses of large-scale social survey data. Bringing this special section on key variables to a close, this final article discusses several important issues relating to the inclusion of key variables in statistical modelling analyses. We outline two, often neglected, issues that are relevant to a great many applications of statistical models based upon social survey data. The first is known as the reference category problem and is related to the interpretation of categorical explanatory variables. The second is the interpretation and comparison of the effects from models for non-linear outcomes. We then briefly discuss other common complexities in using statistical models for social science research; these include the non-linear transformation of variables, and considerations of intersectionality and interaction effects. We conclude by emphasising the importance of two, often overlooked, elements of the social survey data analysis process, sensitivity analysis and documentation for replication. We argue that more attention should routinely be devoted to these issues

A review of educational attainment measures for social survey research

This article is a review of issues associated with measuring education and using educational measures in social science research. The review is orientated towards researchers who undertake secondary analyses of large-scale micro-level social science datasets. The article begins with an outline of important context, which impinges upon the measurement of education. The United Kingdom is the focus of this review, but similar issues apply to other nation states. We provide a critical introduction to the main approaches to measuring education in social survey research, which include measuring years of education, using categorical qualification based measures and scaling approaches. We advocate the use of established education measures to better facilitate comparability and replication. We conclude by making the recommendation that researchers place careful thought into which educational measure they select, and that researchers should routinely engage in appropriate sensitivity analyses

Missing the Unhealthy? Examining Empirical Validity of Material Deprivation Indices (MDIs) Using a Partial Criterion Variable

This study investigates the empirical validity of the material deprivation indices (MDIs) using a partial criterion variable, namely UHCNIR (unmet health care need due to inadequate resources). This alternative approach helps to assess absolute validity (Type I and II errors) and sources of error in the measurement of poverty for a specific aspect of poverty (in this case inability to receive adequate health care due to affordability problems). A simple mismatch analysis identifies a sizable group, around 1% of the adult EU population, missed by MDIs despite being in UHCNIR. A majority of this 1% experiences not only UHCNIR but also multiple other deprivations, commonly reports having some difficulties making ends meet, and prevalently has a disability or a chronic health problem. The analysis reveals that MDIs miss specifically those "unhealthy poor" since these measures do not include a relevant item, and thus cannot adjust for different needs and costs in health care and account for the distinct poverty experiences of these people. Therefore, the main methodological assumption of MDIs, identifying the people in poverty with only a limited set of key deprivation indicators is not supported by this empirical analysis

Gender differences in the prevalence and socio-demographic correlates of mobility disability among older adults in Nigeria

The aim of the current study is to examine gender differences in mobility disability among older people in Nigeria, and to explore factors associated with gender differences in mobility disability in later life. Data were used from the first (2010–2011) wave of the Nigeria General Household Survey-Panel, which included 3586 respondents aged 50 years and above. Mobility disability was assessed as self-reported difficulty in walking 100 m, walking 1 km, walking uphill, running, bending or stooping, and climbing stairs. Regression analyses were used to estimate the extent to which socio-demographic conditions contribute to gender differences in mobility disability. We observed a higher prevalence of mobility disability among women compared to men (20.1 vs. 12.5 %, P < 0.001). The prevalence ratios (PR) of mobility disability for women versus men was 1.61 (95 % CI 1.38–1.88, P < 0.001); after adjusting for age, marital status, place of residence, self-reported health status and cognitive difficulties, the PR was 1.55 (95 % CI 1.30–1.85, P < 0.001). In the fully adjusted model, mobility disability still remained significantly higher among women (PR 1.60, 95 % CI 1.32–1.93, P < 0.001). The marginal effects of socio-demographic and health factors were stronger for women than for men. Socio-demographic and health variables considered in this study explained between 19.3 % (men) and 22.3 % (women) of variance in mobility disability suggesting that additional factors beyond those considered in this study warrant further investigation, so that differences in mobility disability between older men and women in Nigeria can be fully understood