Matching Kasteleyn Cities for Spin Glass Ground States

As spin glass materials have extremely slow dynamics, devious numerical methods are needed to study low-temperature states. A simple and fast optimization version of the classical Kasteleyn treatment of the Ising model is described and applied to two-dimensional Ising spin glasses. The algorithm combines the Pfaffian and matching approaches to directly strip droplet excitations from an excited state. Extended ground states in Ising spin glasses on a torus, which are optimized over all boundary conditions, are used to compute precise values for ground state energy densities.Comment: 4 pages, 2 figures; minor clarification

Macrophages possess probenecid-inhibitable organic anion transporters that remove fluorescent dyes from the cytoplasmic matrix

We introduced several membrane-impermeant fluorescent dyes, including Lucifer Yellow, carboxyfluorescein, and fura-2, into the cytoplasmic matrix of J774 cells and thioglycollate-elicited mouse peritoneal macrophages by ATP permeabilization of the plasma membrane and observed the subsequent fate of these dyes. The dyes did not remain within the cytoplasmic matrix; instead they were sequestered within phase-lucent cytoplasmic vacuoles and released into the extracellular medium. We used Lucifer Yellow to study these processes further. In cells incubated at 37 degrees C, 87% of Lucifer Yellow was released from the cells within 30 min after dye loading. The dye that remained within the cells at this time was predominantly within cytoplasmic vacuoles. Lucifer yellow transport was temperature dependent and occurred against a concentration gradient; therefore it appeared to be an energy-requiring process. The fluorescent dyes used in these studies are all organic anions. We therefore examined the ability of probenecid (p-[dipropylsulfamoyl]benzoic acid), which blocks organic anion transport across many epithelia, to inhibit efflux of Lucifer Yellow, and found that this drug inhibited this process in a dose-dependent and reversible manner. Efflux of Lucifer Yellow from the cells did not require Na+ co-transport or Cl- antiport; however, it was inhibited by lowering of the extracellular pH. These experiments indicate that macrophages possess probenecid-inhibitable transporters which are similar in their functional properties to organic anion transporters of epithelial cells. Such organic anion transporters have not been described previously in macrophages; they may mediate the release of naturally occurring organic anions such as prostaglandins, leukotrienes, glutathione, bilirubin, or lactate from macrophages

Universality in phase boundary slopes for spin glasses on self dual lattices

We study the effects of disorder on the slope of the disorder--temperature phase boundary near the Onsager point (Tc = 2.269...) in spin-glass models. So far, studies have focused on marginal or irrelevant cases of disorder. Using duality arguments, as well as exact Pfaffian techniques we reproduce these analytical estimates. In addition, we obtain different estimates for spin-glass models on hierarchical lattices where the effects of disorder are relevant. We show that the phase-boundary slope near the Onsager point can be used to probe for the relevance of disorder effects.Comment: 8 pages, 6 figure

Stochastic bias of colour-selected BAO tracers by joint clustering-weak lensing analysis

The baryon acoustic oscillation (BAO) feature in the two-point correlation function of galaxies supplies a standard ruler to probe the expansion history of the Universe. We study here several galaxy selection schemes, aiming at building an emission-line galaxy (ELG) sample in the redshift range $0.6<z<1.7$, that would be suitable for future BAO studies, providing a highly biased galaxy sample. We analyse the angular galaxy clustering of galaxy selections at the redshifts 0.5, 0.7, 0.8, 1 and 1.2 and we combine this analysis with a halo occupation distribution (HOD) model to derive the properties of the haloes these galaxies inhabit, in particular the galaxy bias on large scales. We also perform a weak lensing analysis (aperture statistics) to extract the galaxy bias and the cross-correlation coefficient and compare to the HOD prediction. We apply this analysis on a data set composed of the photometry of the deep co-addition on Sloan Digital Sky Survey (SDSS) Stripe 82 (225 deg$^2$), of Canda-France-Hawai Telescope/Stripe 82 deep \emph{i}-band weak lensing survey and of the {\it Wide-Field Infrared Survey Explorer}infrared photometric band W1. The analysis on the SDSS-III/constant mass galaxies selection at $z=0.5$ is in agreement with previous studies on the tracer, moreover we measure its cross-correlation coefficient $r=1.16\pm0.35$. For the higher redshift bins, we confirm the trends that the brightest galaxy populations selected are strongly biased ($b>1.5$), but we are limited by current data sets depth to derive precise values of the galaxy bias. A survey using such tracers of the mass field will guarantee a high significance detection of the BAO.Comment: 17 pages, 15 figures, submitted to MNRA

Methods for the thematic synthesis of qualitative research in systematic reviews

<p>Abstract</p> <p>Background</p> <p>There is a growing recognition of the value of synthesising qualitative research in the evidence base in order to facilitate effective and appropriate health care. In response to this, methods for undertaking these syntheses are currently being developed. Thematic analysis is a method that is often used to analyse data in primary qualitative research. This paper reports on the use of this type of analysis in systematic reviews to bring together and integrate the findings of multiple qualitative studies.</p> <p>Methods</p> <p>We describe thematic synthesis, outline several steps for its conduct and illustrate the process and outcome of this approach using a completed review of health promotion research. Thematic synthesis has three stages: the coding of text 'line-by-line'; the development of 'descriptive themes'; and the generation of 'analytical themes'. While the development of descriptive themes remains 'close' to the primary studies, the analytical themes represent a stage of interpretation whereby the reviewers 'go beyond' the primary studies and generate new interpretive constructs, explanations or hypotheses. The use of computer software can facilitate this method of synthesis; detailed guidance is given on how this can be achieved.</p> <p>Results</p> <p>We used thematic synthesis to combine the studies of children's views and identified key themes to explore in the intervention studies. Most interventions were based in school and often combined learning about health benefits with 'hands-on' experience. The studies of children's views suggested that fruit and vegetables should be treated in different ways, and that messages should not focus on health warnings. Interventions that were in line with these suggestions tended to be more effective. Thematic synthesis enabled us to stay 'close' to the results of the primary studies, synthesising them in a transparent way, and facilitating the explicit production of new concepts and hypotheses.</p> <p>Conclusion</p> <p>We compare thematic synthesis to other methods for the synthesis of qualitative research, discussing issues of context and rigour. Thematic synthesis is presented as a tried and tested method that preserves an explicit and transparent link between conclusions and the text of primary studies; as such it preserves principles that have traditionally been important to systematic reviewing.</p

Recruitment of ethnic minority patients to a cardiac rehabilitation trial: The Birmingham Rehabilitation Uptake Maximisation (BRUM) study [ISRCTN72884263]

Background: Concerns have been raised about low participation rates of people from minority ethnic groups in clinical trials. However, the evidence is unclear as many studies do not report the ethnicity of participants and there is insufficient information about the reasons for ineligibility by ethnic group. Where there are data, there remains the key question as to whether ethnic minorities more likely to be ineligible (e.g. due to language) or decline to participate. We have addressed these questions in relation to the Birmingham Rehabilitation Uptake Maximisation (BRUM) study, a randomized controlled trial (RCT) comparing a home-based with a hospital-based cardiac rehabilitation programme in a multi-ethnic population in the UK. Methods: Analysis of the ethnicity, age and sex of presenting and recruited subjects for a trial of cardiac rehabilitation in the West-Midlands, UK. Participants: 1997 patients presenting post-myocardial infarction, percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery. Data collected: exclusion rates, reasons for exclusion and reasons for declining to participate in the trial by ethnic group. Results: Significantly more patients of South Asian ethnicity were excluded (52% of 'South Asian' v 36% 'White European' and 36% 'Other', p < 0.001). This difference in eligibility was primarily due to exclusion on the basis of language (i.e. the inability to speak English or Punjabi). Of those eligible, similar proportions were recruited from the different ethnic groups (white, South Asian and other). There was a marked difference in eligibility between people of Indian, Pakistani or Bangladeshi origin

Resolution of the clinical features of tyrosinemia following orthotopic liver transplantation for hepatoma

The clinical history before transplantation and subsequent clinical and biochemical course of 3 children and one adult with hereditary tyrosinemia treated by orthotopic hepatic transplantation is described. All four patients are now free of their previous dietary restrictions and appear to be cured of both their metabolic disease and their hepatic neoplasm. © 1986 Elsevier Science Publishers B.V. All rights reserved

Distributed Computing Grid Experiences in CMS

The CMS experiment is currently developing a computing system capable of serving, processing and archiving the large number of events that will be generated when the CMS detector starts taking data. During 2004 CMS undertook a large scale data challenge to demonstrate the ability of the CMS computing system to cope with a sustained data-taking rate equivalent to 25% of startup rate. Its goals were: to run CMS event reconstruction at CERN for a sustained period at 25 Hz input rate; to distribute the data to several regional centers; and enable data access at those centers for analysis. Grid middleware was utilized to help complete all aspects of the challenge. To continue to provide scalable access from anywhere in the world to the data, CMS is developing a layer of software that uses Grid tools to gain access to data and resources, and that aims to provide physicists with a user friendly interface for submitting their analysis jobs. This paper describes the data challenge experience with Grid infrastructure and the current development of the CMS analysis system

Systematic Reviews in Educational Research: Methodology, Perspectives and Application

This chapter explores the processes of reviewing literature as a research method. The logic of the family of research approaches called systematic review is analysed and the variation in techniques used in the different approaches explored using examples from existing reviews. The key distinctions between aggregative and configurative approaches are illustrated and the chapter signposts further reading on key issues in the systematic review process