Confinement of Spin and Charge in High-Temperature Superconductors

By exploiting the internal gauge-invariance intrinsic to a spin-charge separated electron, we show that such degrees of freedom must be confined in two-dimensional superconductors experiencing strong inter-electron repulsion. We also demonstrate that incipient confinement in the normal state can prevent chiral spin-fluctuations from destroying the cross-over between strange and psuedo-gap regimes in under-doped high-temperature superconductors. Last, we suggest that the negative Hall anomaly observed in these materials is connected with this confinement effect.Comment: 12 pages, 1 postscript figure, to appear in PRB (RC), May 199

Postnatal β-cell maturation is associated with islet-specific microRNA changes induced by nutrient shifts at weaning.

Glucose-induced insulin secretion is an essential function of pancreatic β-cells that is partially lost in individuals affected by Type 2 diabetes. This unique property of β-cells is acquired through a poorly understood postnatal maturation process involving major modifications in gene expression programs. Here we show that β-cell maturation is associated with changes in microRNA expression induced by the nutritional transition that occurs at weaning. When mimicked in newborn islet cells, modifications in the level of specific microRNAs result in a switch in the expression of metabolic enzymes and cause the acquisition of glucose-induced insulin release. Our data suggest microRNAs have a central role in postnatal β-cell maturation and in the determination of adult functional β-cell mass. A better understanding of the events governing β-cell maturation may help understand why some individuals are predisposed to developing diabetes and could lead to new strategies for the treatment of this common metabolic disease

Editorial

Editoria

Low Temperature Measurements by Infrared Spectroscopy in CoFe2_2O4_4 Ceramic

In this paper results of new far-infrared and middle-infrared measurements (wavenumber range of 4000cm-1 - 100cm-1) in the range of the temperature from 300K to 8K of the CoFe2O4 ceramic are presented. The bands positions and their shapes are the same in the wide temperature range. The quality of the sample was investigated by X-ray, EDS and EPMA studies. The CoFe2O4 reveals the cubic structure (Fd-3m) in the temperature range from 85K to 360 K without any traces of distortion. On the current level of knowledge the polycrystalline CoFe2O4 does not exhibit phase transition in the temperature range from 8 K to 300 K.Comment: 10 pages, 6 figure

An evaluation of enhanced geotextile layer in permeable pavement to improve stormwater infiltration and attenuation

This paper reports on an evaluation of the properties of a novel structure known as OASIS® which was designed at Coventry University as an enhancement of the commercially available geotextiles when incorporated in the permeable pavement system (PPS). The impact on the hydraulic behaviour of a PPS was analysed through the study of infiltration rate, throughout the PPS and time required to reach the steady-state stage behaviour of the water within the PPS, under extreme rainfall intensities of 100 mm/hr, 200 mm/hr and 400 mm/hr, corresponding to a 100-year return period rainfall over a duration of 15 min in different parts of the world. The result indicated that the novel structure provides an extra benefit when incorporated in PPSs, delaying peak flow of a rainfall event by retaining and storing great volumes of water within its structure. These additional benefits are especially important under extreme rainfall events

Geometry and material effects in Casimir physics - Scattering theory

We give a comprehensive presentation of methods for calculating the Casimir force to arbitrary accuracy, for any number of objects, arbitrary shapes, susceptibility functions, and separations. The technique is applicable to objects immersed in media other than vacuum, to nonzero temperatures, and to spatial arrangements in which one object is enclosed in another. Our method combines each object's classical electromagnetic scattering amplitude with universal translation matrices, which convert between the bases used to calculate scattering for each object, but are otherwise independent of the details of the individual objects. This approach, which combines methods of statistical physics and scattering theory, is well suited to analyze many diverse phenomena. We illustrate its power and versatility by a number of examples, which show how the interplay of geometry and material properties helps to understand and control Casimir forces. We also examine whether electrodynamic Casimir forces can lead to stable levitation. Neglecting permeabilities, we prove that any equilibrium position of objects subject to such forces is unstable if the permittivities of all objects are higher or lower than that of the enveloping medium; the former being the generic case for ordinary materials in vacuum.Comment: 44 pages, 11 figures, to appear in upcoming Lecture Notes in Physics volume in Casimir physic

Land use, residential density, and walking. The multi-ethnic study of atherosclerosis.

BACKGROUND: The neighborhood environment may play a role in encouraging sedentary patterns, especially for middle-aged and older adults. PURPOSE: The aim of this study was to examine the associations between walking and neighborhood population density, retail availability, and land-use distribution using data from a cohort of adults aged 45 to 84 years. METHODS: Data from a multi-ethnic sample of 5529 adult residents of Baltimore MD, Chicago IL, Forsyth County NC, Los Angeles CA, New York NY, and St. Paul MN enrolled in the Multi-Ethnic Study of Atherosclerosis in 2000-2002 were linked to secondary land-use and population data. Participant reports of access to destinations and stores and objective measures of the percentage of land area in parcels devoted to retail land uses, the population divided by land area in parcels, and the mixture of uses for areas within 200 m of each participant's residence were examined. Multinomial logistic regression was used to investigate associations of self-reported and objective neighborhood characteristics with walking. All analyses were conducted in 2008 and 2009. RESULTS: After adjustment for individual-level characteristics and neighborhood connectivity, it was found that higher density, greater land area devoted to retail uses, and self-reported proximity of destinations and ease of walking to places were each related to walking. In models including all land-use measures, population density was positively associated with walking to places and with walking for exercise for more than 90 minutes/week, both relative to no walking. Availability of retail was associated with walking to places relative to not walking, and having a more proportional mix of land uses was associated with walking for exercise for more than 90 minutes/week, while self-reported ease of access to places was related to higher levels of exercise walking, both relative to not walking. CONCLUSIONS: Residential density and the presence of retail uses are related to various walking behaviors. Efforts to increase walking may benefit from attention to the intensity and type of land development.http://deepblue.lib.umich.edu/bitstream/2027.42/78515/1/RodriguezEvenson2009_Am J Prev Med.pd

A spatial analysis of health-related resources in three diverse metropolitan areas

Few studies have investigated the spatial clustering of multiple health-related resources. We constructed 0.5 mile kernel densities of resources for census areas in New York City, NY (n=819 block groups), Baltimore, MD (n=737), and Winston-Salem, NC (n=169). Three of the four resource densities (supermarkets/produce stores, retail areas, and recreational facilities) tended to be correlated with each other, whereas park density was less consistently and sometimes negatively correlated with others. Blacks were more likely to live in block groups with multiple low resource densities. Spatial regression models showed that block groups with higher proportions of black residents tended to have lower supermarket/produce, retail, and recreational facility densities, although these associations did not always achieve statistical significance. A measure that combined local and neighboring block group racial composition was often a stronger predictor of resources than the local measure alone. Overall, our results from three diverse U.S. cities show that health-related resources are not randomly distributed across space and that disadvantage in multiple domains often clusters with residential racial patterning.http://deepblue.lib.umich.edu/bitstream/2027.42/78330/1/SmileyDiezRoux2010_HealthPlace.pd