Optimizing the ensemble for equilibration in broad-histogram Monte Carlo simulations

We present an adaptive algorithm which optimizes the statistical-mechanical ensemble in a generalized broad-histogram Monte Carlo simulation to maximize the system's rate of round trips in total energy. The scaling of the mean round-trip time from the ground state to the maximum entropy state for this local-update method is found to be O([N log N]^2) for both the ferromagnetic and the fully frustrated 2D Ising model with N spins. Our new algorithm thereby substantially outperforms flat-histogram methods such as the Wang-Landau algorithm.Comment: 6 pages, 5 figure

Characterisation of bulk water samples from copper pipes undergoing microbially influenced corrosion by diagnostic metabolomic profiling

This paper presents the application of metabolomic techniques to determine the presence of microbial influenced corrosion (MIC). In a previous study, the extracellular metabolites expressed from pipe biofilm was identified by analysing the passing water. This investigation extends this work by successfully applying a chemometric statistical analysis to the extracellular metabolomic profile of a number of water samples to identify critical metabolomic biomarkers. The chemometric analysis was able to differentiate samples due to a reduction of carboxylic acids in samples exposed to bacteria believed to cause MIC

Absolute differential positronium-formation cross sections

The first absolute experimental determinations of the differential cross-sections for the formation of ground-state positronium are presented for He, Ar, H2 and CO2 near 0○. Results are compared with available theories. The ratio of the differential and integrated cross-sections for the targets exposes the higher propensity for forward-emission of positronium formed from He and H2

Detection of s-Triazine pesticides in natural waters by modified large-volume direct injection HPLC

There is a need for simple and inexpensive methods to quantify potentially harmful persistent pesticides often found in our water-ways and water distribution systems. This paper presents a simple, relatively inexpensive method for the detection of a group of commonly used pesticides (atrazine, simazine and hexazinone) in natural waters using large-volume direct injection high performance liquid chromatography (HPLC) utilizing a monolithic column and a single wavelength ultraviolet–visible light (UV–vis) detector. The best results for this system were obtained with a mobile phase made up of acetonitrile and water in a 30:70 ratio, a flow rate of 2.0 mL min−1, and a detector wavelength of 230 nm. Using this method, we achieved retention times of less than three minutes, and detection limits of 5.7 μg L−1 for atrazine, 4.7 μg L−1 for simazine and 4.0 μg L−1 for hexazinone. The performance of this method was validated with an inter-laboratory trial against a National Association of Testing Authorities (NATA) accredited liquid chromatography–mass spectrometry/mass spectrometry (LC–MS/MS) method commonly used in commercial laboratories

Nonexistence of self-similar singularities for the 3D incompressible Euler equations

We prove that there exists no self-similar finite time blowing up solution to the 3D incompressible Euler equations. By similar method we also show nonexistence of self-similar blowing up solutions to the divergence-free transport equation in $\Bbb R^n$. This result has direct applications to the density dependent Euler equations, the Boussinesq system, and the quasi-geostrophic equations, for which we also show nonexistence of self-similar blowing up solutions.Comment: This version refines the previous one by relaxing the condition of compact support for the vorticit

Distributions of fecal markers in wastewater from different climatic zones for human fecal pollution tracking in Australian surface waters

Recreational and potable water supplies polluted with human wastewater can pose a direct health risk to humans. Therefore, sensitive detection of human fecal pollution in environmental waters is very important to water quality authorities around the globe. Microbial source tracking (MST) utilizes human fecal markers (HFMs) to detect human wastewater pollution in environmental waters. The concentrations of these markers in raw wastewater are considered important because it is likely that a marker whose concentration is high in wastewater will be more frequently detected in polluted waters. In this study, quantitative PCR (qPCR) assays were used to determine the concentrations of fecal indicator bacteria (FIB) Escherichia coli and Enterococcus spp., HFMs Bacteroides HF183, human adenoviruses (HAdVs), and polyomaviruses (HPyVs) in raw municipal wastewater influent from various climatic zones in Australia. E. coli mean concentrations in pooled human wastewater data sets (from various climatic zones) were the highest (3.2 × 10 gene copies per ml), followed by those of HF183 (8.0 × 10 gene copies per ml) and Enterococcus spp. (3.6 × 10 gene copies per ml). HAdV and HPyV concentrations were 2 to 3 orders of magnitude lower than those of FIB and HF183. Strong positive and negative correlations were observed between the FIB and HFM concentrations within and across wastewater treatment plants (WWTPs). To identify the most sensitive marker of human fecal pollution, environmental water samples were seeded with raw human wastewater. The results from the seeding experiments indicated that Bacteroides HF183 was more sensitive for detecting human fecal pollution than HAdVs and HPyVs. Since the HF183 marker can occasionally be present in nontarget animal fecal samples, it is recommended that HF183 along with a viral marker (HAdVs or HPyVs) be used for tracking human fecal pollution in Australian environmental waters

Probability-Changing Cluster Algorithm: Study of Three-Dimensional Ising Model and Percolation Problem

We present a detailed description of the idea and procedure for the newly proposed Monte Carlo algorithm of tuning the critical point automatically, which is called the probability-changing cluster (PCC) algorithm [Y. Tomita and Y. Okabe, Phys. Rev. Lett. {\bf 86} (2001) 572]. Using the PCC algorithm, we investigate the three-dimensional Ising model and the bond percolation problem. We employ a refined finite-size scaling analysis to make estimates of critical point and exponents. With much less efforts, we obtain the results which are consistent with the previous calculations. We argue several directions for the application of the PCC algorithm.Comment: 6 pages including 8 eps figures, to appear in J. Phys. Soc. Jp

Health Technology Scenarios and Implications for Spectrum

Supporting Informatio

Council tax valuation bands, socio-economic status and health outcome: a cross-sectional analysis from the Caerphilly Health and Social Needs Study

Council tax valuation bands (CTVBs) are a categorisation of household property value in Great Britain. The aim of the study was to assess the CTVB as a measure of socio-economic status by comparing the strength of the associations between selected health and lifestyle outcomes and CTVBs with two measures of socio-economic status: the National Statistics Socio-Economic Classification (NS-SEC) and the 2001 UK census-based Townsend deprivation index. METHODS: Cross-sectional analysis of data on 12,092 respondents (adjusted response 62.7%) to the Caerphilly Health and Social Needs Study, a postal questionnaire survey undertaken in Caerphilly county borough, south-east Wales, UK. The CTVB was assigned to each individual by matching the sampling frame to the local authority council tax register. Crude and age-gender adjusted odds ratios for each category of CTVB, NS-SEC and fifth of the ward distribution of Townsend scores were estimated for smoking, poor diet, obesity, and limiting long-term illness using logistic regression. Mean mental (MCS) and physical (PCS) component summary scores of the Short-Form SF-36 health status questionnaire were estimated in general linear models. RESULTS: There were significant trends in odds ratios across the CTVB categories for all outcomes, most marked for smoking and mental and physical health status. The adjusted odds ratio for being a smoker in the lowest versus highest CTVB category was 3.80 (95% CI: 3.06, 4.71), compared to 3.00 (95% CI: 2.30, 3.90) for the NS-SEC 'never worked and long-term unemployed' versus 'higher managerial and professional' categories, and 1.61 (95% CI: 1.42, 1.83) for the most deprived versus the least deprived Townsend fifth. The difference in adjusted mean MCS scores was 5.9 points on the scale for CTVB, 9.2 for NS-SEC and 3.2 for the Townsend score. The values for the adjusted mean PCS scores were 6.3 points for CTVB, 11.3 for NS-SEC, and 2.5 for the Townsend score. CONCLUSION: CTVBs assigned to individuals were strongly associated with the health and lifestyle outcomes modelled in this study. CTVBs are readily available for all residential properties and deserve further consideration as a proxy for socio-economic status in epidemiological studies in Great Britain