33,557 research outputs found
Evidence of Two Distinct Dynamic Critical Exponents in Connection with Vortex Physics
The dynamic critical exponent is determined from numerical simulations
for the three-dimensional (3D) lattice Coulomb gas (LCG) and the 3D XY models
with relaxational dynamics. It is suggested that the dynamics is characterized
by two distinct dynamic critical indices and related to the
divergence of the relaxation time by and
, where is the correlation length and the
wavevector. The values determined are and for the
3D LCG and and for the 3D XY model. It is argued
that the nonlinear exponent relates to , whereas the usual
Hohenberg-Halperin classification relates to . Possible implications for the
interpretation of experiments are pointed out. Comparisons with other existing
results are discussed.Comment: to appear in PR
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Rac GTPases in Human Diseases
Rho GTPases are members of the Ras superfamily of GTPases that regulate a wide variety of cellular functions. While Rho GTPase pathways have been implicated in various pathological conditions in humans, to date coding mutations in only the hematopoietic specific GTPase, RAC2, have been found to cause a human disease, a severe phagocytic immunodeficiency characterized by life-threatening infections in infancy. Interestingly, the phenotype was predicted by a mouse knock-out of RAC2 and resembles leukocyte adhesion deficiency (LAD). Here we review Rho GTPases with a specific focus on Rac GTPases. In particular, we discuss a new understanding of the unique and overlapping roles of Rac2 in blood cells that has developed since the generation of mice deficient in Rac1, Rac2 and Rac3 proteins. We propose that Rac2 mutations leading to disease be termed LAD type IV
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Fight or flight? Crime as a driving force in business failure and business mobility.
A growing body of research has documented the consequences of neighborhood crime for a myriad of individual, household, and community outcomes. Given that neighborhood businesses figure into the link between neighborhood structure and crime as sources of employment or sites for neighbor interaction, the present study examines the extent to which neighborhood crime is associated with the survival, mobility, and destination locations of businesses in the subsequent year. Using business data from Reference USA (Infogroup, 2015) and crime data from the Southern California Crime Study (SCCS) we assess this question for neighborhoods across cities in the Southern California region. We find that in general, higher violent and property crime are significantly associated with both business failure and mobility, and that higher crime in a destination neighborhood reduces the likelihood that a business locates there. We also present findings specific to industries, and discuss the implications of our findings for future research
Confirmation of the Electrostatic Self-Assembly of Nanodiamonds
A reliable explanation for the underlying mechanism responsible for the
persistent aggregation and self-assembly of colloidal 5 nm diamond
nanoparticles is critical to the development of nanodiamond-based technologies.
Although a number of mechanisms have been proposed, validation has been
hindered by the inherent difficulty associated with the identification and
characterisation of the inter-particle interfaces. In this paper we present
results of high resolution aberration corrected electron microscopy and
complementary computer simulations to explicate the features involved, and
confirm the electrostatic interaction mechanism as the most probable cause for
the formation of agglutinates and agglomerates of primary particles.Comment: 9 pages (including Supplementary Information), accepted for
publication by Nanoscal
Country planning for health interventions under development: lessons from the malaria vaccine decision-making framework and implications for other new interventions
Traditionally it has taken years or decades for new public health interventions targeting diseases found in developing countries to be accessible to those most in need. One reason for the delay has been insufficient anticipation of the eventual processes and evidence required for decision making by countries. This paper describes research into the anticipated processes and data needed to inform decision making on malaria vaccines, the most advanced of which is still in phase 3 trials. From 2006 to 2008, a series of country consultations in Africa led to the development of a guide to assist countries in preparing their malaria vaccine decision-making frameworks. The guide builds upon the World Health Organization’s Vaccine Introduction Guidelines. It identifies the processes and data for decisions, when they would be needed relative to the development timelines of the intervention, and where they will come from. Policy development will be supported by data (e.g. malaria disease burden; roles of other malaria interventions; malaria vaccine impact; economic and financial issues; malaria vaccine efficacy, quality and safety) as will implementation decisions (e.g. programmatic issues and socio-cultural environment). This generic guide can now be applied to any future malaria vaccine. The paper discusses the opportunities and challenges to early planning for country decision-making—from the potential for timely, evidence-informed decisions to the risks of over-promising around an intervention still under development. Careful and well-structured planning by countries is an important way to ensure that new interventions do not remain unused for years or decades after they become available
Evaluation of the efficacy of Alpron disinfectant for dental unit water lines
AIMS: To assess the efficacy of a disinfectant, Alpron, for controlling microbial contamination within dental unit water lines. METHODS: The microbiological quality of water emerging from the triple syringe, high speed handpiece, cup filler and surgery hand wash basin from six dental units was assessed for microbiological total viable counts at 22 degrees C and 37 degrees C before and after treatment with Alpron solutions. RESULTS: The study found that the use of Alpron disinfectant solutions could reduce microbial counts in dental unit water lines to similar levels for drinking water. This effect was maintained in all units for up to six weeks following one course of treatment. In four out of six units the low microbial counts were maintained for 13 weeks. CONCLUSIONS: Disinfectants may have a short term role to play in controlling microbial contamination of dental unit water lines to drinking water quality. However, in the longer term attention must be paid to redesigning dental units to discourage the build up of microbial biofilms
Report on the Findings of the 2004 Australian National eProcurement Survey
This report highlights the key findings from the 2004 Australian National eProcurement Survey. The aim of the 2004 Australian National eProcurement Survey is to establish the nature, extent and adoption profile of eProcurement strategies and processes of Australian organisations.Australian Research Council (Grant No. LP0214841
Report on the Findings of the 2004 Australian National eProcurement Survey
This report highlights the key findings from the 2004 Australian National eProcurement Survey. The aim of the 2004 Australian National eProcurement Survey is to establish the nature, extent and adoption profile of eProcurement strategies and processes of Australian organisations.Australian Research Council (Grant No. LP0214841
Spiral shocks and the formation of molecular clouds in a two phase medium
We extend recent numerical results (Dobbs et. al. 2006) on molecular cloud
formation in spiral galaxies by including a multi-phase medium. The addition of
a hot phase of gas enhances the structure in the cold gas, and significantly
increases the fraction of molecular hydrogen that is formed when the cold gas
passes through a spiral shock. The difference in structure is reflected in the
mass power spectrum of the molecular clouds, which is steeper for the
multi-phase calculations. The increase in molecular gas occurs as the addition
of a hot phase leads to higher densities in the cold gas. In particular, cold
gas is confined in clumps between the spiral arms and retains a higher
molecular fraction. Unlike the single phase results, molecular clouds are
present in the inter-arm regions for the multi-phase medium. However the
density of the inter-arm molecular hydrogen is generally below that which can
be reliably determined from CO measurements. We therefore predict that for a
multi-phase medium, there will be low density clouds containing cold atomic and
molecular hydrogen, which are potentially entering the spiral arms.Comment: 11 pages, 14 figures, accepted for publication in MNRA
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