The Macro-Economic and Sectoral Impacts of HIV and AIDS in India

The adverse economic impact of HIV and AIDS occurs at three levels : the individual/household, sector, and national or macro-levels. In the early phase of the epidemic, the impacts at the sector and macro-levels are rather mild and, hence, not easily measurable or quantifiable. So far in India, given the low overall prevalence, the focus has been on the effects at the level of the individual and the household. The enlisted study, by Pradhan, Sundar and Singh (2006)1 also focuses on the impact of HIV and AIDS on affected households, which it finds to be seriously adverse, and, therefore, a matter of acute concern. At the same time, the study underplays the adverse economywide impact of AIDS. Given the current prevalence rate, the extrapolation of the household-level impact to the level of the state or the national economy does not reveal a large macro-economic impact. But, this is because the survey, on which the study is based, captures the snapshot of the economy at a given point of time, while the question of the macroeconomic impact of AIDS is essentially a dynamic one. As the HIV epidemic unfolds, its impacts are bound to be deeply compounded. These impacts cannot be assessed in their totality by a mere extrapolation of the household level impact. Furthermore, in 2005, the number of HIV-infected persons exceeds 5 million, and this number is expected to quintuple to between 20 million and 25 million by 2010. With that kind of a jump in the number of HIV cases in the next 5-10 years, there is bound to be a visible impact on the national economy. At present, little or nothing is known about the potential macro-economic impact of HIV and AIDS on the Indian economy. The rough-and-ready estimates of the macro-economic costs of AIDS that are available are of no help in guiding and accelerating the response of the Government of India to the potential threat to the economy imposed by this epidemic. A quantitative assessment of the macro-economic impact of AIDS on the Indian economy, therefore, needs to be undertaken urgently to assist the policy makers. Keeping this in mind, the study analyses the macro-economic and sectoral impacts of HIV and AIDS in India, using a fivesector computable general equilibrium (CGE) model.HIV, AIDS, macroeconomic impact of AIDS, computable general equilibrium

Additivity property and emergence of power laws in nonequilibrium steady states

We show that an equilibriumlike additivity property can remarkably lead to power-law distributions observed frequently in a wide class of out-of-equilibrium systems. The additivity property can determine the full scaling form of the distribution functions and the associated exponents. The asymptotic behavior of these distributions is solely governed by branch-cut singularity in the variance of subsystem mass. To substantiate these claims, we explicitly calculate, using the additivity property, subsystem mass distributions in a wide class of previously studied mass aggregation models as well as in their variants. These results could help in the thermodynamic characterization of nonequilibrium critical phenomena.Comment: Revised longer version, 4 figure

Highly Excited Core Resonances in Photoionization of Fe XVII : Implications for Plasma Opacities

A comprehensive study of high-accuracy photoionization cross sections is carried out using the relativistic Breit-Pauli R-matrix (BPRM) method for (hnu + Fe XVII --> Fe XVIII + e). Owing to its importance in high-temperature plasmas the calculations cover a large energy range, particularly the myriad photoexciation-of-core (PEC) resonances including the n = 3 levels not heretofore considered. The calculations employ a close coupling wave function expansion of 60 levels of the core ion Fe XVIII ranging over a wide energy range of nearly 900 eV between the n = 2 and n = 3 levels. Strong coupling effects due to dipole transition arrays 2p^5 --> 2p^4 (3s,3d) manifest themselves as large PEC resonances throughout this range, and enhance the effective photoionization cross sections orders of magnitude above the background. Comparisons with the erstwhile Opacity Project (OP) and other previous calculations shows that the currently available cross sections considerably underestimate the bound-free cross sections. A level-identification scheme is used for spectroscopic designation of the 454 bound fine structure levels of Fe XVII. Level-specific photoionization cross sections are computed for all levels. In addition, partial cross sections for leaving the core ion Fe XVII in the ground state are also obtained. These results should be relevant to modeling of astrophysical and laboratory plasma sources requiring (i) photoionization rates, (ii) extensive non-local-thermodynamic-equilibrium models, (iii) total unified electron-ion recombination rates including radiative and dielectronic recombination, and (iv) plasma opacities. We particularly examine PEC and non-PEC resonance strengths and emphasize their expanded role to incorporate inner-shell excitations for improved opacities, as shown by the computed monochromatic opacity of Fe XVII.Comment: 12 pages, 5 figures, Physical Review A (in press

Magnetic Order Beyond RKKY in the Classical Kondo Lattice

We study the Kondo lattice model of band electrons coupled to classical spins, in three dimensions, using a combination of variational calculation and Monte Carlo. We use the weak coupling `RKKY' window and the strong coupling regime as benchmarks, but focus on the physically relevant intermediate coupling regime. Even for modest electron-spin coupling the phase boundaries move away from the RKKY results, the non interacting Fermi surface no longer dictates magnetic order, and weak coupling `spiral' phases give way to collinear order. We use these results to revisit the classic problem of 4f magnetism and demonstrate how both electronic structure and coupling effects beyond RKKY control the magnetism in these materials.Comment: 6 pages, 4 figs. Improved figures, expanded captions. To appear in Europhys. Let