Infra-red Divergences in Light-Front QED and Coherent State Basis

We present a next to leading order calculation of electron mass renormalization in Light-Front Quantum Electrodynamics (LFQED) using old-fashioned time ordered perturbation theory (TOPT). We show that the true infrared divergences in $\delta m^2$ get canceled up to $O(e^4)$ if one uses coherent state basis instead of fock basis to calculate the transition matrix elements.Comment: 44 pages,11 figure

Renormalized quark-antiquark Hamiltonian induced by a gluon mass ansatz in heavy-flavor QCD

In response to the growing need for theoretical tools that can be used in QCD to describe and understand the dynamics of gluons in hadrons in the Minkowski space-time, the renormalization group procedure for effective particles (RGPEP) is shown in the simplest available context of heavy quarkonia to exhibit a welcome degree of universality in the first approximation it yields once one assumes that beyond perturbation theory gluons obtain effective mass. Namely, in the second-order terms, the Coulomb potential with Breit-Fermi spin couplings in the effective quark-antiquark component of a heavy quarkonium, is corrected in one-flavor QCD by a spin-independent harmonic oscillator term that does not depend on the assumed effective gluon mass or the choice of the RGPEP generator. The new generator we use here is much simpler than the ones used before and has the advantage of being suitable for studies of the effective gluon dynamics at higher orders than the second and beyond the perturbative expansion.Comment: 8 pages, 2 figures, journal versio

Design, fabrication, and test of a composite material wind turbine rotor blade

The aerodynamic design, structural design, fabrication, and structural testing is described for a 60 foot long filament wound, fiberglass/epoxy resin matrix wind turbine rotor blade for a 125 foot diameter, 100 kW wind energy conversion system. One blade was fabricated which met all aerodynamic shape requirements and was structurally capable of operating under all specified design conditions. The feasibility of filament winding large rotor blades was demonstrated

Inequalities in maternity care and newborn outcomes: one-year surveillance of births in vulnerable slum communities in Mumbai

Background: Aggregate urban health statistics mask inequalities. We described maternity care in vulnerable slum communities in Mumbai, and examined differences in care and outcomes between more and less deprived groups. Methods: We collected information through a birth surveillance system covering a population of over 280 000 in 48 vulnerable slum localities. Resident women identified births in their own localities and mothers and families were interviewed at 6 weeks after delivery. We analysed data on 5687 births over one year to September 2006. Socioeconomic status was classified using quartiles of standardized asset scores. Results: Women in higher socioeconomic quartile groups were less likely to have married and conceived in their teens (Odds ratio 0.74, 95% confidence interval 0.69–0.79, and 0.82, 0.78–0.87, respectively). There was a socioeconomic gradient away from public sector maternity care with increasing socioeconomic status (0.75, 0.70–0.79 for antenatal care and 0.66, 0.61–0.71 for institutional delivery). Women in the least poor group were five times less likely to deliver at home (0.17, 0.10–0.27) as women in the poorest group and about four times less likely to deliver in the public sector (0.27, 0.21–0.35). Rising socioeconomic status was associated with a lower prevalence of low birth weight (0.91, 0.85–0.97). Stillbirth rates did not vary, but neonatal mortality rates fell non-significantly as socioeconomic status increased (0.88, 0.71–1.08). Conclusion: Analyses of this type have usually been applied across the population spectrum from richest to poorest, and we were struck by the regularly stepped picture of inequalities within the urban poor, a group that might inadvertently be considered relatively homogeneous. The poorest slum residents are more dependent upon public sector health care, but the regular progression towards the private sector raises questions about its quality and regulation. It also underlines the need for healthcare provision strategies to take account of both sectors

Deuterium-deuterium nuclear cross-sections in insulator and metallic environments

The three-dimensional Thomas-Fermi (TF) model is used to simulate the variation of the d+d to t + p cross-section at low impact energies, when the target deuterium nucleus is embedded in metallic or insulator environments. Comparison of the computational results to recent experiments demonstrates that even though the TF model can explain some increase in the low energy cross section for metallic host, a full explanation of the experimental results is still lacking. Possible reasons for the disagreement are discussed.Comment: 6 pages;6 figures. Accepted for publication in Eur. Phys. Jour.