Anomalous Hall effect in field-effect structures of (Ga,Mn)As

The anomalous Hall effect in metal-insulator-semiconductor structures having thin (Ga,Mn)As layers as a channel has been studied in a wide range of Mn and hole densities changed by the gate electric field. Strong and unanticipated temperature dependence, including a change of sign, of the anomalous Hall conductance $\sigma_{xy}$ has been found in samples with the highest Curie temperatures. For more disordered channels, the scaling relation between $\sigma_{xy}$ and $\sigma_{xx}$, similar to the one observed previously for thicker samples, is recovered.Comment: 5 pages, 5 figure

Magnetic properties of nanosized diluted magnetic semiconductors with band splitting

The continual model of the nonuniform magnetism in thin films and wires of a diluted magnetic semiconductor is considered with taking into account the finite spin polarization of carriers responsible for the indirect interaction of magnetic impurities (e.g. via RKKY mechanism). Spatial distributions (across the film thickness or the wire radius) of the magnetizaton and carrier concentrations of different spin orientations, as well as the temperature dependence of the average magnetization are determined as the solution of the nonlinear integral equation

On the merit of a Central Limit Theorem-based approximation in statistical physics

The applicability conditions of a recently reported Central Limit Theorem-based approximation method in statistical physics are investigated and rigorously determined. The failure of this method at low and intermediate temperature is proved as well as its inadequacy to disclose quantum criticalities at fixed temperatures. Its high temperature predictions are in addition shown to coincide with those stemming from straightforward appropriate expansions up to (k_B T)^(-2). Our results are clearly illustrated by comparing the exact and approximate temperature dependence of the free energy of some exemplary physical systems.Comment: 12 pages, 1 figur

Evaluation of Sub-National Population Projections: a Case Study for London and the Thames Valley

Sub-national population projections help allocate national funding to local areas for planning local services. For example, water utilities prepare plans to meet future water demand over long-term horizons. Future demand depends on projected populations and households and forecasts of per household and per capita domestic water consumption in supply zones. This paper reports on population projections prepared for a water utility, Thames Water, which supplies water to over nine million people in London and the Thames Valley. Thames Water required an evaluation of the accuracy of the delivered projections against alternatives and estimates of uncertainty. The paper reviews how such evaluations have been made by researchers. The factors leading to variation in sub-national projections are identified. The methods, assumptions and results for English sub-national areas, used in five sets of projections, are compared. There is a consensus across projections about the future fertility and mortality but varying views about the future impact of internal and international migration flows. However, the greatest differences were between projections using ethnic populations. and those using homogeneous populations. Areas with high populations of ethnic minorities were projected to grow faster when an ethnic-specific model was used. This result is important for assessing projections for countries housing diverse populations with different demographic profiles. Historic empirical prediction intervals are used to assess the uncertainty of the London and the Thames Valley projections. By 2101 the preferred projection suggests that the population of the Thames Water region will have grown by 85% within an 80% empirical prediction interval between 45 and 125%

Relations between pig growth and regulatory mechanism of pancreas - facts and hypotheses

The aim of the mini review is to more precisely determine the relationship between exocrine pancreas function and the growth of young pigs. In order to do so, it is necessary to clarify the components, pathways and messengers involved in the CCK-dependent neuro-hormonal regulation of the exocrine pancreas in the growing pigs. These mechanisms are largely unknown, and the role of CCK has been questioned since CCK receptors on the enzyme producing acinar cells are lacking. Our hitherto obtained results have shown the importance of CCK for the pancreatic enzyme secretion and that in pigs CCK functions via CCK-B receptor-mediated entero(duodenal)-pancreatic reflex and via CCK-A receptor mechanism which localization is unknown. Preliminary studies have indicated this later mechanism as being related to the growth performance of pigs. The planned studies will comprise a pharmacologic characterization and an immunohistologic localization of the components and messengers involved in the CCK-dependent neuro-hormonal pancreatic regulation using an appropriately catheterized pig model. Since the applied aim of the project is to correlate the growth of the pigs to the effectiveness of the pancreatic secretion and to the development of its regulatory mechanisms, the experiments will be performed on pigs having different growth and performance. It is expected that the discussion will provide important applicable understanding of pancreatic function and its impact on pig growth and performance and also highlight the mechanism of the inter-organ regulatory pathways of the exocrine pancreatic function