Conditions for equivalence of Statistical Ensembles in Nuclear Multifragmentation

Statistical models based on canonical and grand canonical ensembles are extensively used to study intermediate energy heavy ion collisions. The underlying physical assumption behind canonical and grand canonical models is fundamentally different, and in principle agree only in the thermodynamical limit when the number of particles become infinite. Nevertheless, we show that these models are equivalent in the sense that they predict similar results if certain conditions are met even for finite nuclei. In particular, the results converge when nuclear multifragmentation leads to the formation of predominantly nucleons and low mass clusters. The conditions under which the equivalence holds are amenable to present day experiments.Comment: 5 pages, 5 figure

Effect of transients in nuclear fission on multiplicity of prescission neutrons

Transients in the fission of highly excited nuclei are studied in the framework of the Langevin equation. Time-dependent fission widths are calculated which show that after the initial transients, a steady flow towards the scission point is established not only for nuclei which have fission barriers but also for nuclei which have no fission barrier. It is shown from a comparison of the transient time and the fission life time that fission changes from a diffusive to a transient dominated process over a certain transition region as a function of the spin of the fissioning nucleus. Multiplicities of prescission neutrons are calculated in a statistical model with as well as without a single swoop description of fission and they are found to differ in the transition region. We however find that the difference is marginal and hence a single swoop picture of fission though not strictly valid in the transition region can still be used in the statistical model calculations.Comment: 15 pages including 7 figures, to appear in The European Physical Journal

An investigation into poverty among domestic maids in Lusaka, Zambia

Despite tall claims of GDP growth, Zambian Poverty remained un addressed. Zambia has drafted its first Poverty Reduction Strategy Paper (PRSP) in 2002-2005 and mainstreamed the successive poverty reduction strategies into the National Development Plans beginning with the Fifth National Development Plan (FNDP) 2006-2010. Zambia after independence has progressively moved southwards in terms of GDP growth and achieved the status of Highly Indebted Poor Country (HIPC). Nevertheless, Zambia’s progress reports show some achievements in GDP growth and containing poverty during the initial years of FNDP. The midterm review reports show that there has been a growth in GDP and poverty reduction in Zambia, and more reduction in urban poverty. These claims have led me to find out “Has the GDP growth during the Fifth National Development Plan resulted in poverty reduction among the most vulnerable women workers- the domestic maids in Lusaka?” In the process of determining this, a review of Zambian Economy, the urban poverty levels; growth in GDP before and after FNDP; and living standards of randomly selected Domestic Maids from different compounds in Lusaka have been analyzed, evaluated and related to poverty reduction, growth and development theories. To support the analysis, a questionnaire (Appendix-I) was designed and data was collected from eight domestic maids. Apart from the primary data collection process, some data was recorded from the offices of Government of Zambia, FNDP, PRSP, and living standard surveys conducted by the United Nations Organization present in Zambia. From the information composed the appropriate data has been utilized effectively to analyze it and arrive at conclusions. In conclusion it is found that the growth in GDP and reduction in poverty levels have no tangible impact on the poverty levels of domestic maids in Lusaka.Domestic Maids, Poverty Reduction, Lusaka, Zambian Economy, Hingly Indebted Poor Country

Field-control, phase-transitions, and life's emergence

Instances of critical-like characteristics in living systems at each organizational level as well as the spontaneous emergence of computation (Langton), indicate the relevance of self-organized criticality (SOC). But extrapolating complex bio-systems to life's origins, brings up a paradox: how could simple organics--lacking the 'soft matter' response properties of today's bio-molecules--have dissipated energy from primordial reactions in a controlled manner for their 'ordering'? Nevertheless, a causal link of life's macroscopic irreversible dynamics to the microscopic reversible laws of statistical mechanics is indicated via the 'functional-takeover' of a soft magnetic scaffold by organics (c.f. Cairns-Smith's 'crystal-scaffold'). A field-controlled structure offers a mechanism for bootstrapping--bottom-up assembly with top-down control: its super-paramagnetic components obey reversible dynamics, but its dissipation of H-field energy for aggregation breaks time-reversal symmetry. The responsive adjustments of the controlled (host) mineral system to environmental changes would bring about mutual coupling between random organic sets supported by it; here the generation of long-range correlations within organic (guest) networks could include SOC-like mechanisms. And, such cooperative adjustments enable the selection of the functional configuration by altering the inorganic network's capacity to assist a spontaneous process. A non-equilibrium dynamics could now drive the kinetically-oriented system towards a series of phase-transitions with appropriate organic replacements 'taking-over' its functions.Comment: 54 pages, pdf fil