Orthogonal Polynomial Representation of Imaginary-Time Green's Functions

We study the expansion of single-particle and two-particle imaginary-time Matsubara Green's functions of quantum impurity models in the basis of Legendre orthogonal polynomials. We discuss various applications within the dynamical mean-field theory (DMFT) framework. The method provides a more compact representation of the Green's functions than standard Matsubara frequencies and therefore significantly reduces the memory-storage size of these quantities. Moreover, it can be used as an efficient noise filter for various physical quantities within the continuous-time quantum Monte Carlo impurity solvers recently developed for DMFT and its extensions. In particular, we show how to use it for the computation of energies in the context of realistic DMFT calculations in combination with the local density approximation to the density functional theory (LDA+DMFT) and for the calculation of lattice susceptibilities from the local irreducible vertex function.Comment: 14 pages, 11 figure

Chromosome mapping: radiation hybrid data and stochastic spin models

This work approaches human chromosome mapping by developing algorithms for ordering markers associated with radiation hybrid data. Motivated by recent work of Boehnke et al. [1], we formulate the ordering problem by developing stochastic spin models to search for minimum-break marker configurations. As a particular application, the methods developed are applied to 14 human chromosome-21 markers tested by Cox et al. [2]. The methods generate configurations consistent with the best found by others. Additionally, we find that the set of low-lying configurations is described by a Markov-like ordering probability distribution. The distribution displays cluster correlations reflecting closely linked loci.Comment: 26 Pages, uuencoded LaTex, Submitted to Phys. Rev. E, [email protected], [email protected]

Toxic effects of indocyanine green, infracyanine green, and trypan blue on the human retinal pigmented epithelium

Background: Indocyanine green, infracyanine green, and trypan blue are frequently used as aids to visualize structures removed during vitreoretinal surgery. But they may have toxic effects on the retina. We therefore compared the acute and chronic toxicities of these stains on cultured human retinal pigmented epithelial (RPE) cells using clinically relevant concentrations and an identical experimental setup for each agent. Methods: Monolayers of RPE cells were incubated with various concentrations of indocyanine green, infracyanine green (each at 0.005%, 0.05%, and 0.5%) or trypan blue (0.05%, 0.06%, 0.1%, 0.15%, and 0.5%) for 5min (acute exposure) or 6 days (chronic exposure). Using the propidium iodide assay, acute cytotoxicity was monitored at 15-min intervals for up to 3h. Chronic cytotoxicity was assessed by monitoring cell calcein esterase activity, cell proliferation, and cell morphology (viability) after 6 days of exposure. Results: Indocyanine and infracyanine green induced acute and chronic toxicities at a concentration above 0.05%. Trypan blue evoked no acute toxicity, but it was chronically cytotoxic at all tested concentrations. Conclusions: Despite thorough rinsing after application, significant amounts of the not sufficiently water soluble indocyanine and infracyanine green are retained after surgery by the eye. Trypan blue, being more water-soluble than ICG, is probably retained to the least degree. This circumstance is fortunate given that trypan blue exhibits a chronic cytotoxicity comparable to ICG at all clinically relevant concentrations. During vitrectomy, surgeons should aim to expose retinal tissue to only low concentrations of these stains and for as short a period as possibl

A meeting report: OECD-GESIS Seminar on Translating and Adapting Instruments in Large-Scale Assessments (2018)

This report summarizes the main themes and conclusions from the OECD-GESIS Seminar on Translating and Adapting Instruments in Large-Scale Assessments, which took place at the Organization for Economic Co-operation and Development (OECD), Paris, in June 2018. The five sessions covered the topics (1) etic (universal) vs. emic (culture-specific) measurement instruments, (2) language- and culture-sensitive development of measurement instruments, (3) international guidelines vs. implementation in countries and by translators, (4) tools and technological developments, and (5) quality control of translations. Key players in the field presented on best practice, lessons learned, and innovations and also made suggestions for moving the field forward

LocusZoom: regional visualization of genome-wide association scan results

Summary: Genome-wide association studies (GWAS) have revealed hundreds of loci associated with common human genetic diseases and traits. We have developed a web-based plotting tool that provides fast visual display of GWAS results in a publication-ready format. LocusZoom visually displays regional information such as the strength and extent of the association signal relative to genomic position, local linkage disequilibrium (LD) and recombination patterns and the positions of genes in the region

Genetic risk scores in the prediction of plasma glucose, impaired insulin secretion, insulin resistance and incident type 2 diabetes in the METSIM study

Aims/hypothesis: Many SNPs have been associated with glycaemic traits and type 2 diabetes, but their joint effects on glycaemic traits and the underlying mechanisms leading to hyperglycaemia over time are largely unknown. We aimed to investigate the association of six genetic risk scores (GRSs) with changes in plasma glucose, insulin sensitivity, insulin secretion and incident type 2 diabetes in the prospective METabolic Syndrome In Men (METSIM) study. Methods: We generated weighted GRSs for fasting plasma glucose ([FPG] GRSFPG, 35 SNPs), 2 h plasma glucose ([2hPG] GRS2hPG, 9 SNPs), insulin secretion (GRSIS, 17 SNPs), insulin resistance (GRSIR, 9 SNPs) and BMI (GRSBMI, 95 SNPs) and a non-weighted GRS for type 2 diabetes (GRST2D, 76 SNPs) in up to 8749 non-diabetic Finnish men. Linear regression was used to test associations of the GRSs with changes in glycaemic traits over time. Results: GRST2D, GRSFPG and GRSIS were associated with an increase in FPG, GRST2D with an increase in glucose AUC and a decrease in insulin secretion, and GRS2hPG with an increase in 2hPG during the follow-up (p < 0.0017 for all models). GRST2D, GRSFPG and GRSIS were associated with incident type 2 diabetes (p < 0.008 for all models). GRSBMI and GRSIR were not significantly associated with any changes in glycaemic traits. Conclusions/interpretation: In the METSIM follow-up study, GRST2D, GRSFPG and GRSIS were associated with the worsening of FPG and an increase in incident type 2 diabetes. GRST2D was additionally associated with a decrease in insulin secretion, and GRS2hPG with an increase in 2hPG

Bayesian methods and optimal experimental design for gene mapping by radiation hybrids

Radiation hybrid mapping is a somatic cell technique for ordering human loci along a chromosome and estimating the physical distance between adjacent loci. The present paper considers a realistic model of fragment generation and retention. This model assumes that fragments are generated in the ancestral cell of a clone according to a Poisson breakage process along the chromosome. Once generated, fragments are independently retained in the clone with a common retention probability. Based on this and less restrictive models, statistical criteria such as minimum obligate breaks, maximum likelihood, and Bayesian posterior probabilities can be used to decide order. Distances can be estimated by either maximum likelihood or Bayesian posterior means. The model also permits rational design of radiation dose for optimal statistical precision. A brief examination of some real data illustrates our criteria and computational algorithms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65749/1/j.1469-1809.1992.tb01139.x.pd

Knowledge and response to the COVID-19 pandemic in people with severe mental illness in Bangladesh and Pakistan:A cross-sectional survey

BACKGROUND: People with severe mental illnesses (SMIs) are likely to face disproportionate challenges during a pandemic. They may not receive or be able to respond to public health messages to prevent infection or to limit its spread. Additionally, they may be more severely affected, particularly in low- and middle-income countries. METHODS: We conducted a telephone survey (May–June 2020) in a sample of 1,299 people with SMI who had attended national mental health institutes in Bangladesh and Pakistan before the pandemic. We collected information on top worries, socioeconomic impact of the pandemic, knowledge of COVID-19 (symptoms, prevention), and prevention-related practices (social distancing, hygiene). We explored the predictive value of socio-demographic and health-related variables for relative levels of COVID-19 knowledge and practice using regularized logistic regression models. FINDINGS: Mass media were the major source of information about COVID-19. Finances, employment, and physical health were the most frequently mentioned concerns. Overall, participants reported good knowledge and following advice. In Bangladesh, being female and higher levels of health-related quality of life (HRQoL) predicted poor and better knowledge, respectively, while in Pakistan being female predicted better knowledge. Receiving information from television predicted better knowledge in both countries. In Bangladesh, being female, accessing information from multiple media sources, and better HRQoL predicted better practice. In Pakistan, poorer knowledge of COVID-19 prevention measures predicted poorer practice. CONCLUSION: Our paper adds to the literature on people living with SMIs and their knowledge and practices relevant to COVID-19 prevention. Our results emphasize the importance of access to mass and social media for the dissemination of advice and that the likely gendered uptake of both knowledge and practice requires further attention