First excited state calculation using different phonon bases for the two-site Holstein model

The single-electron energy and static charge-lattice deformation correlations have been calculated for the first excited state of a two-site Holstein model within perturbative expansions using different standard phonon bases obtained through Lang-Firsov (LF) transformation, LF with squeezed phonon states, modified LF, modified LF transformation with squeezed phonon states, and also within weak-coupling perturbation approach. Comparisons of the convergence of the perturbative expansions for different phonon bases reveal that modified LF approach works much better than other approaches for major range of the coupling strength.Comment: 11 pages (REVTEX), 4 postscript figure

Dynamics of Fluctuation Dominated Phase Ordering: Hard-core Passive Sliders on a Fluctuating Surface

We study the dynamics of a system of hard-core particles sliding downwards on a one dimensional fluctuating interface, which in a special case can be mapped to the problem of a passive scalar advected by a Burgers fluid. Driven by the surface fluctuations, the particles show a tendency to cluster, but the hard-core interaction prevents collapse. We use numerical simulations to measure the auto-correlation function in steady state and in the aging regime, and space-time correlation functions in steady state. We have also calculated these quantities analytically in a related surface model. The steady state auto-correlation is a scaling function of t/L^z, where L is the system size and z the dynamic exponent. Starting from a finite intercept, the scaling function decays with a cusp, in the small argument limit. The finite value of the intercept indicates the existence of long range order in the system. The space-time correlation, which is a function of r/L and t/L^z, is non-monotonic in t for fixed r. The aging auto-correlation is a scaling function of t_1 and t_2 where t_1 is the waiting time and t_2 the time difference. This scaling function decays as a power law for t_2 \gg t_1; for t_1 \gg t_2, it decays with a cusp as in steady state. To reconcile the occurrence of strong fluctuations in the steady state with the fact of an ordered state, we measured the distribution function of the length of the largest cluster. This shows that fluctuations never destroy ordering, but rather the system meanders from one ordered configuration to another on a relatively rapid time scale

ACUTE PORPHYRIA AMONGST PSYCHIATRIC PATIENTS

A total of 519 consecutive patients, admitted to psychiatric wards of two different hospitals, were screened for evidence of increased excretion of porphobilinogen in the urine by original Watson Schwartz test and modified Watson Schwartz test supported with quantitative estimation of porphobilinogen by Remington's method in search of cases of acute porphyria amongst psychiatric patients. An additional 273 normal healthy volunteers were also screened as controls. Two cases (0.38%) were found which could be unequivocally diagnosed to be suffering from acute intermittent porphyria amongst psychiatric patients. These cases belonged to the category of missed diagnosis being labelled as hysterical. Seven more cases were positive by modified Watson Schwartz test but the test was only transiently positive and the Ehrlichaldehyde reactor substance was unstable. In the absence of detailed enzymatic and family studies, these cases have been kept under the category of suspected prophyria. A significant number of psychiatric patients (12.9%) gave positive original Watson-Schwartz test but were negative for modified test. Similar reaction was seen in 2.6% of healthy controls. The significance of this finding needs to be evaluated

The pure effect of social preferences on regional location choices: The evolving dynamics of convergence to a steady state population distribution

This paper tracks the consequences of individuals’ desire to align their location with their social preferences. The social preference studied in the paper is distaste for relative deprivation, measured in a cardinal manner. Location is conceived as social space, with individuals choosing to relocate if, as a result, their relative deprivation will be reduced, holding their incomes constant. Conditions are provided under which the associated dynamics reaches a spatial steady state, the number of periods it takes to reach a steady state is specified, and light is shed on the robustness of the steady state outcome. By way of simulation it is shown that for large populations, a steady state of the relocation dynamics is almost always reached, typically in one period, and that cycles are more likely to occur when the populations’ income distributions are more equal

Indigenous entrepreneurship: Closing the gap on local terms

Australian federal government policy over the last ten years has renewed the focus on closing the gap between Indigenous and non-Indigenous Australians, targeting chiefly improvements in health and economic participation among Indigenous people. Thus far, however, the results have been mixed, in part because of the endurance of Indigenous socio-economic disadvantage in Australia which cannot be expected to be undone within a matter of years. Failure to deliver better policy outcomes, however, can also be seen as a function of an inflexible policy design, which aims at the mainstreaming of Indigenous communities on non-Indigenous terms, whilst militating against the potential for Indigenous entrepreneurial activities especially in rural and remote regions.Against this policy background, this paper reports on local entrepreneurial activities by local Yolngu clans in East Arnhem Land in the Northern Territories (NT). In particular, attention is directed to local for-profit and not-for-profit activities by members of the Gumatj clan south of the regional centre of Nhulunbuy and the Rirratjingu operations in the town Yirrkala respectively. The paper describes how the ventures run by the Gumatj and Rirratjingu clans offer pathways for the creation of income, employment and social capital within the respective local communities whilst also being axiomatic in the protection of cultural vitality and integrity. The findings point to the need for more flexible approaches to policy design and delivery, enabling the establishment and growth of Indigenous business activities outside the economic mainstream targeted by federal government policy. As such, the authors echo calls in the literature for policy support for what has been described as the 'hybrid economy', which allows for participation in both economic and cultural activities both of which are crucial for Indigenous future well-being as they are for any cultural group

Dynamics of Shock Probes in Driven Diffusive Systems

We study the dynamics of shock-tracking probe particles in driven diffusive systems and also in equilibrium systems. In a driven system, they induce a diverging timescale that marks the crossover between a passive scalar regime at early times and a diffusive regime at late times; a scaling form characterises this crossover. Introduction of probes into an equilibrium system gives rise to a system-wide density gradient, and the presence of even a single probe can be felt across the entire system.Comment: Accepted in Journal of Statistical Mechanics: Theory and Experimen

Rate of convergence of linear functions on the unitary group

We study the rate of convergence to a normal random variable of the real and imaginary parts of Tr(AU), where U is an N x N random unitary matrix and A is a deterministic complex matrix. We show that the rate of convergence is O(N^{-2 + b}), with 0 <= b < 1, depending only on the asymptotic behaviour of the singular values of A; for example, if the singular values are non-degenerate, different from zero and O(1) as N -> infinity, then b=0. The proof uses a Berry-Esse'en inequality for linear combinations of eigenvalues of random unitary, matrices, and so appropriate for strongly dependent random variables.Comment: 34 pages, 1 figure; corrected typos, added remark 3.3, added 3 reference

The Vertical Structure of Warm Ionised Gas in the Milky Way

We present a new joint analysis of pulsar dispersion measures and diffuse H-alpha emission in the Milky Way, which we use to derive the density, pressure and filling factor of the thick disk component of the warm ionised medium (WIM) as a function of height above the Galactic disk. By excluding sightlines at low Galactic latitude that are contaminated by HII regions and spiral arms, we find that the exponential scale-height of free electrons in the diffuse WIM is 1830 (+120, -250) pc, a factor of two larger than has been derived in previous studies. The corresponding inconsistent scale heights for dispersion measure and emission measure imply that the vertical profiles of mass and pressure in the WIM are decoupled, and that the filling factor of WIM clouds is a geometric response to the competing environmental influences of thermal and non-thermal processes. Extrapolating the properties of the thick-disk WIM to mid-plane, we infer a volume-averaged electron density 0.014 +- 0.001 cm^-3, produced by clouds of typical electron density 0.34 +- 0.06 cm^-3 with a volume filling factor 0.04 +- 0.01. As one moves off the plane, the filling factor increases to a maximum of ~30% at a height of approximately 1-1.5 kpc, before then declining to accommodate the increasing presence of hot, coronal gas. Since models for the WIM with a ~1 kpc scale-height have been widely used to estimate distances to radio pulsars, our revised parameters suggest that the distances to many high-latitude pulsars have been substantially underestimated.Comment: 20 pages, including 5 PS figures (4 in color). Publications of the Astronomical Society of Australia, in pres