Scanning tunneling spectroscopy of a dilute two-dimensional electron system exhibiting Rashba spin splitting

Using scanning tunneling spectroscopy (STS) at 5 K in B-fields up to 7 T, we investigate the local density of states of a two-dimensional electron system (2DES) created by Cs adsorption on p-type InSb(110). The 2DES, which in contrast to previous STS studies exhibits a 2D Fermi level, shows standing waves at B = 0 T with corrugations decreasing with energy and with wave numbers in accordance with theory. In magnetic field percolating drift states are observed within the disorder broadened Landau levels. Due to the large electric field perpendicular to the surface, a beating pattern of the Landau levels is found and explained quantitatively by Rashba spin splitting within the lowest 2DES subband. The Rashba splitting does not contribute significantly to the standing wave patterns in accordance with theory.Comment: 9 pages, 9 figures, submitted to Phys. Rev.

A Note on Flux Induced Superpotentials in String Theory

Non-vanishing fluxes in M-theory and string theory compactifications induce a superpotential in the lower dimensional theory. Gukov has conjectured the explicit form of this superpotential. We check this conjecture for the heterotic string compactified on a Calabi-Yau three-fold as well as for warped M-theory compactifications on Spin(7) holonomy manifolds, by performing a Kaluza-Klein reduction.Comment: 19 pages, no figure

Disability in Kazakhstan : an evaluation of official data

In order to answer the questions of (a) what is the true pattern of disability in Kazakhstan; (b) whether the incidence of disability is decreasing; and (c) what is the life expectancy of Kazakhstan's disabled, this paper attempts first to create an historical picture of disability in Kazakhstan by analyzing government population statistics and studying the evolution of disability determination procedure in the former Soviet Union and independent Kazakhstan. Doing so is not a trivial task, as there has been almost no systematic research, either in Russian or English. The paper concludes that the optimistic official picture of disability patterns in Kazakhstan is almost certainly inaccurate. The paper details that the quality of official disability data is high, and much can be learned from the patterns. However, changing definitions and strictness of enforcement make time series comparisons problematic, and the improvements in adult disability recorded are inconsistent both with trends for children, and with mortality trends. Rather, the authors note that barriers for applying disability benefits have increased and incentives to report disabilities have decreased markedly in the past 15 years, so that it is virtually certain that there is substantial hidden disability.Population Policies,Disease Control&Prevention,Disability,,Social Protections&Assistance

Cosmic Microwave Background constraints of decaying dark matter particle properties

If a component of cosmological dark matter is made up of massive particles - such as sterile neutrinos - that decay with cosmological lifetime to emit photons, the reionization history of the universe would be affected, and cosmic microwave background anisotropies can be used to constrain such a decaying particle model of dark matter. The optical depth depends rather sensitively on the decaying dark matter particle mass m_{dm}, lifetime tau_{dm}, and the mass fraction of cold dark matter f that they account for in this model. Assuming that there are no other sources of reionization and using the WMAP 7-year data, we find that 250 eV < m_{dm} < 1 MeV, whereas 2.23*10^3 yr < tau_{dm} < 1.23*10^18 yr. The best fit values for m_{dm} and tau_{dm}/f are 17.3 keV and 2.03*10^16 yr respectively.Comment: 17 pages, 3 figure

Kazakhstan's Pension System: Pressures for Change and Dramatic Reforms

Five years ago, Kazakhstan embarked on a dramatic reform of its pension and social security system in order to move from an unsustainable public defined benefit ("solidarity") system to one of defined mandatory contributions (accumulative system). While assessment of long-run success is premature, early results have exceeded expectations. This paper considers the reform's rationale and initial impact: Why did the Government of Kazakhstan decide to introduce a new pension system? What advantages did the state perceive? Was the Government's decision appropriate, and what alternatives existed? The paper also analyzes pension reform issues that have yet to be fully resolved.

Fertility and Marriage in Kazakhstan's Transition Period: Implications for Social Security Policy

Seven years ago, Kazakhstan embarked on a dramatic reform of its pension and social security system in order to move from an unsustainable public defined benefit ("solidarity") system to one of defined mandatory contributions (accumulative system). While much has been written on the financial implications for individual contributors, and on macro budgetary impacts, there has been no examination of how changing demographic structure is likely to affect the size of vulnerable pools. This paper explores the impact of these changes, and links demographic structure to economic performance. Focusing on changes in nuptiality (marriage) and fertility, we conclude that demographic structural shifts will increase overall system risk, but that current trends are favorable.