Research on WASH sector, environment and water resources in the Central Rift Valley of Ethiopia

Peer ReviewedPostprint (published version

Equation of State in a Strongly Interacting Relativistic System

We study the evolution of the equation of state of a strongly interacting quark system as a function of the diquark interaction strength. We show that for the system to avoid collapsing into a pressureless Boson gas at sufficiently strong diquark coupling strength, the diquark-diquark repulsion has to be self-consistently taken into account. In particular, we find that the tendency at zero temperature of the strongly interacting diquark gas to condense into the system ground state is compensated by the repulsion between diquarks if the diquark-diquark coupling constant is higher than a critical value $\lambda_C=7.65$. Considering such diquark-diquark repulsion, a positive pressure with no significant variation along the whole strongly interacting region is obtained. A consequence of the diquark-diquark repulsion is that the system maintains its BCS character in the whole strongly interacting region.Comment: 9 pages, 7 figs, To appear in Phys. Rev.

Effects of Bose-Einstein Condensation on forces among bodies sitting in a boson heat bath

We explore the consequences of Bose-Einstein condensation on two-scalar-exchange mediated forces among bodies that sit in a boson gas. We find that below the condensation temperature the range of the forces becomes infinite while it is finite at temperatures above condensation.Comment: 10 pages, 2 figure

The Subjective Costs of Health Losses Due to Chronic Diseases: An Alternative Model for Monetary Appraisal

This paper proposes a method to evaluate health losses or gains by looking at the impact on well-being of a change in health status. The paper presents estimates of the equivalent income change that would be necessary to change general satisfaction with life to the same extent as a change in health satisfaction would do. In other words, we estimate the income equivalent of health changes. Next, the health satisfaction changes are linked to specific diseases in order to estimate the income equivalent for various diseases. This method uses answers to well-being and health satisfaction questions as posed in a large German data set. We distinguish between workers and non-workers and between inhabitants of East- and West- Germany. We find, for instance, that for West-workers hearing impediments are on average equivalent to an income reduction of about 20%, and that heart blood difficulties are for the same group equivalent to a 47% income reduction.chronic diseases, equivalent income, health damages, health satisfaction, well-being.

Income Satisfaction Inequality and Its Causes

In this paper, the concept of Income Satisfaction Inequality is operationalized on the basis of individual responses to an Income Satisfaction question posed in the German Socio-Economic Panel (GSOEP). Income satisfaction is the subjective analogue of the objective income concept and includes objective income inequality as a special case. The paper introduces a method to decompose Income Satisfaction Inequality according to the contributions from variables such as income, education, and the number of children. Given the panel structure of the data, inequality may be attributed partly to permanent individual circumstances and partly to transitory changes. The paper shows that by far the largest part of the satisfaction inequality has to be ascribed to unobserved heterogeneity. Distinguishing between a structural and an unexplained part of inequality we find that income explains the largest part of structural Income Satisfaction Inequality together with household membership; for non-working individuals, the age distribution is very relevant as well.Equivalent Income, Financial Satisfaction, Income Satisfaction, Income Inequality, Variance Decomposition.

ab inito local vibrational modes of light impurities in silicon

We have developed a formulation of density functional perturbation theory for the calculation of vibrational frequencies in molecules and solids, which uses numerical atomic orbitals as a basis set for the electronic states. The (harmonic) dynamical matrix is extracted directly from the first order change in the density matrix with respect to infinitesimal atomic displacements from the equilibrium configuration. We have applied this method to study the vibrational properties of a number of hydrogen-related complexes and light impurities in silicon. The diagonalization of the dynamical matrix provides the vibrational modes and frequencies, including the local vibrational modes (LVMs) associated with the defects. In addition to tests on simple molecules, results for interstitial hydrogen, hydrogen dimers, vacancy-hydrogen and self-interstitial-hydrogen complexes, the boron-hydrogen pair, substitutional C, and several O-related defects in c-Si are presented. The average error relative to experiment for the aprox.60 predicted LVMs is about 2% with most highly harmonic modes being extremely close and the more anharmonic ones within 5-6% of the measured values.Comment: 18 pages, 1 figur

The Anatomy of Subjective Well-Being

Subjective Well-Being has increasingly been studied by several economists. This paper fits in that literature but takes into account that there are different aspects of life such as health, financial situation, and job. We call them domains. In this paper, we consider Subjective Well-Being as a composite of various domain satisfactions (DS). We postulate a two -layer model where individual Subjective Well-Being is explained by individual subjective domain satisfactions with respect to job, finance, health, leisure, housing, and environment. We distinguish between long -term and short - term effects. Next, we explain domain satisfactions and Subjective Well-Being by objectively measurable variables such as income. We estimate a model for the GS and DS equations with individual random effects and fix time effects.Subjective Well-Being, satisfaction measurement, qualitative regressors, health satisfaction, job satisfaction

Tuning the electrical conductivity of nanotube-encapsulated metallocene wires

We analyze a new family of carbon nanotube-based molecular wires, formed by encapsulating metallocene molecules inside the nanotubes. Our simulations, that are based on a combination of non-equilibrium Green function techniques and density functional theory, indicate that these wires can be engineered to exhibit desirable magnetotransport effects for use in spintronics devices. The proposed structures should also be resilient to room-temperature fluctuations, and are expected to have a high yield.Comment: 4 pages, 6 figures. Accepted in Physical Review Letter