Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA

Correlations between charged particles in deep inelastic ep scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C

Household headship and child death: Evidence from Nepal

<p>Abstract</p> <p>Background</p> <p>Nepal has seen substantial improvements in its reproductive health outcomes, but infant and child mortality are still high. This study attempts to examine the prevalence and factors influencing the experience of child death of mothers who have given birth during a five-year period. More specifically, this paper aims to investigate whether household headship has an impact on child death in Nepal.</p> <p>Methods</p> <p>This paper reports on data drawn from the Nepal Demographic and Health Survey (NDHS 2006), a nationally representative sample survey. The analysis is confined to women who had given birth during the five years preceding the survey (n = 4066). The association between experience of child death of mother and the explanatory variables was assessed via bivariate analysis using a chi-square test. The variables were also examined using multivariate analysis (binary logistic regression) to assess the net effect of household headship on child death after controlling for the other variables.</p> <p>Results</p> <p>Out of all the mothers who had given birth during a five-years period, 3,229 (79.4%) were from male-headed households; the remaining 837 (20.6%) were from female-headed households. A significantly higher proportion of mothers from male-headed households (6.5%) than female-headed households (4.5%) had experienced the death of a child over the five years preceding the survey. Several socio-demographic, economic, and cultural variables were significant predicators for death of a child. For instance, women who had given birth to three or more children and who were Hindu were more likely to experience a child's death than were their counterparts. On the other hand, women who were literate, who had ever used family planning methods, who had visited a health facility, who utilized antenatal care for the last pregnancy, and who were from female-headed households were less likely to see a child die than were women in their comparison group. Notably, keeping all other control variables constant in the logistic model, women from female-headed households were 31 percent less likely to experience the death of a child (odds ratio = 0.69) than were women from male-headed households.</p> <p>Conclusion</p> <p>The death of children is not uncommon in Nepal. No single factor can account for the high child mortality in the country; many factors contribute to the problem. After controlling for other variables, this study found that, among many other factors, household headship was a strong predictor. Programs seeking to help remedy this problem should focus on the issues identified here regarding women's autonomy, such as reducing the number of children born, increasing women's literacy status, increasing the use of family planning, increasing the use of antenatal care, and increasing female household headship so that child mortality will decrease and the overall well-being of the family can be maintained and enhance.</p

Demographic, socio-economic, and cultural factors affecting fertility differentials in Nepal

<p>Abstract</p> <p>Background</p> <p>Traditionally Nepalese society favors high fertility. Children are a symbol of well-being both socially and economically. Although fertility has been decreasing in Nepal since 1981, it is still high compared to many other developing countries. This paper is an attempt to examine the demographic, socio-economic, and cultural factors for fertility differentials in Nepal.</p> <p>Methods</p> <p>This paper has used data from the Nepal Demographic and Health Survey (NDHS 2006). The analysis is confined to ever married women of reproductive age (8,644). Both bivariate and multivariate analyses have been performed to describe the fertility differentials. The bivariate analysis (one-way ANOVA) was applied to examine the association between children ever born and women's demographic, socio-economic, and cultural characteristics. Besides bivariate analysis, the net effect of each independent variable on the dependent variable after controlling for the effect of other predictors has also been measured through multivariate analysis (multiple linear regressions).</p> <p>Results</p> <p>The mean numbers of children ever born (CEB) among married Nepali women of reproductive age and among women aged 40-49 were three and five children, respectively. There are considerable differentials in the average number of children ever born according to women's demographic, socio-economic, and cultural settings. Regression analysis revealed that age at first marriage, perceived ideal number of children, place of residence, literacy status, religion, mass media exposure, use of family planning methods, household headship, and experience of child death were the most important variables that explained the variance in fertility. Women who considered a higher number of children as ideal (β = 0.03; p < 0.001), those who resided in rural areas (β = 0.02; p < 0.05), Muslim women (β = 0.07; p < 0.001), those who had ever used family planning methods (β = 0.08; p < 0.001), and those who had a child-death experience (β = 0.31; p < 0.001) were more likely to have a higher number of CEB compared to their counterparts. On the other hand, those who married at a later age (β = -0.15; p < 0.001), were literate (β = -0.05; p < 0.001), were exposed to both (radio/TV) mass media (β = -0.05; p < 0.001), were richest (β = -0.12; p < 0.001), and were from female-headed households (β = -0.02; p < 0.05) had a lower number of children ever born than their counterparts.</p> <p>Conclusion</p> <p>The average number of children ever born is high among women in Nepal. There are many contributing factors for the high fertility, among which are age at first marriage, perceived ideal number of children, literacy status, mass media exposure, wealth status, and child-death experience by mothers. All of these were strong predictors for CEB. It can be concluded that programs should aim to reduce fertility rates by focusing on these identified factors so that fertility as well as infant and maternal mortality and morbidity will be decreased and the overall well-being of the family maintained and enhanced.</p

Angular and Current-target Correlations in Deep Inelastic Scattering at HERA

Correlations between charged particles in deep inelastic e+ p scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation

Measurement of Proton-dissociative Diffractive Photoproduction of Vector Mesons at Large Momentum Transfer at HERA: The ZEUS Collaboration

Diffractive photoproduction of vector mesons, γp → VY, where Y is a proton-dissociative system, has been measured in e+p interactions with the ZEUS detector at HERA using an integrated luminosity of 25 pb-1. The differential cross section, dσ/dt, is presented for 1.2 \u3c -t \u3c 12 GeV2, where t is the square of the four-momentum transferred to the vector meson. The data span the range in photon-proton centre-of-mass energy, W, from 80 GeV to 120 GeV. The t distributions are well fit by a power law, dσ/dt ∝ (-t)-n. The slope of the effective Pomeron trajectory, measured from the W dependence of the ρ0 and φ cross sections in bins of t, is consistent with zero. The ratios dσγp→φY/dt to dσγp→ρ0Y/dt and dσγp→J/ψY/dt to dσγp→ρ0Y/dt increase with increasing -t. Decay-angle analyses for ρ0, φ and J/ψ mesons have been carried out. For the ρ0 and φ mesons, contributions from single and double helicity flip are observed. The results are compared to expectations of theoretical models