Error in Monte Carlo, quasi-error in Quasi-Monte Carlo

While the Quasi-Monte Carlo method of numerical integration achieves smaller integration error than standard Monte Carlo, its use in particle physics phenomenology has been hindered by the abscence of a reliable way to estimate that error. The standard Monte Carlo error estimator relies on the assumption that the points are generated independently of each other and, therefore, fails to account for the error improvement advertised by the Quasi-Monte Carlo method. We advocate the construction of an estimator of stochastic nature, based on the ensemble of pointsets with a particular discrepancy value. We investigate the consequences of this choice and give some first empirical results on the suggested estimators.Comment: 41 pages, 19 figure

Pandemic Paranoia in the General Population:International Prevalence and Sociodemographic Profile

BACKGROUND: The term ‘pandemic paranoia’ has been coined to refer to heightened levels of mistrust and suspicion towards other people specifically due to the COVID-19 pandemic. In this study, we examine the international prevalence of pandemic paranoia in the general population and its associated sociodemographic profile. METHODS: A representative international sample of general population adults (N = 2510) from five sites (USA N = 535, Germany N = 516, UK N = 512, Australia N = 502 and Hong Kong N = 445) were recruited using stratified quota sampling (for age, sex, educational attainment) and completed the Pandemic Paranoia Scale (PPS). RESULTS: The overall prevalence rate of pandemic paranoia was 19%, and was highest in Australia and lowest in Germany. On the subscales of the PPS, prevalence was 11% for persecutory threat, 29% for paranoid conspiracy and 37% for interpersonal mistrust. Site and general paranoia significantly predicted pandemic paranoia. Sociodemographic variables (lower age, higher population size and income, being male, employed and no migrant status) explained additional variance and significantly improved prediction of pandemic paranoia. CONCLUSIONS: Pandemic paranoia was relatively common in a representative sample of the general population across five international sites. Sociodemographic variables explained a small but significant amount of the variance in pandemic paranoia

RELATE-a randomised controlled feasibility trial of a Relating Therapy module for distressing auditory verbal hallucinations: a study protocol

Introduction Auditory verbal hallucinations (AVHs) are associated with distress and reduced functioning. Research suggests that distress is associated with the voice hearer's responding to AVH in a passive and subordinate manner. A novel approach focuses on relating to AVH and teaches assertive responses to AVH using experiential role-plays. A small pilot study found a large effect of this approach on AVH distress but an independent multicentre study is required to ascertain effectiveness across different settings. We aim to estimate the expected effect for a subsequent trial to demonstrate that adding a module of Relating Therapy (RT) to treatment as usual (TAU) is superior to TAU alone in reducing AVH distress. We also test the feasibility of patient recruitment, therapist training, and therapy monitoring in different psychological and psychiatric outpatient facilities in Germany. Methods and analysis We will recruit 75 patients diagnosed with a schizophrenia spectrum disorder and persistent distressing AVH across four sites. Patients will be randomised to receive either 16 sessions of RT plus TAU or TAU alone within a 5-month period. Randomisation will be stratified by sites. Single-blind assessments will take place at baseline, at 5 months (T1) and at 9 months (T2). The primary outcome is the distress factor score of the AVH subscale of the Psychotic Symptoms Rating Scale at T2 adjusted for the baseline value. Secondary outcomes are change in depressive symptoms, quality of life, time spent in structured activities as well as negative relating to voices and to other people. Ethics and dissemination The trial has received ethical approval from the German Psychological Society Ethics Committee. The trial results will be disseminated through conference presentations, peer-reviewed publications and social media

Growth of epitaxially oriented Ag nanoislands on air-oxidized Si(111)-(7x7) surfaces: Influence of short range order on the substrate

Clean Si(111)-(7{x7) surfaces, followed by air-exposure, have been investigated by reflection high energy electron diffraction (RHEED) and scanning tunneling microscopy (STM). Fourier transforms (FTs) of STM images show the presence of short range (7x7) order on the air-oxidized surface. Comparison with FTs of STM images from a clean Si(111)-(7x7) surface shows that only the 1/7th order spots are present on the air-oxidized surface. The oxide layer is ~ 2-3 nm thick, as revealed by cross-sectional transmission electron microscopy (XTEM). Growth of Ag islands on these air-oxidized Si(111)-(7x7) surfaces has been investigated by in-situ RHEED and STM and ex-situ XTEM and scanning electron microscopy. Ag deposition at room temperature leads to the growth of randomly oriented Ag islands while preferred orientation evolves when Ag is deposited at higher substrate temperatures. For deposition at 550{\deg}C face centered cubic Ag nanoislands grow with a predominant epitaxial orientation [1 -1 0]Ag || [1 -1 0]Si, (111)Ag || (111)Si along with its twin [-1 1 0]Ag || [1 -1 0]Si, (111)Ag || (111)Si, as observed for epitaxial growth of Ag on Si(111) surfaces. The twins are thus rotated by a 180{\deg} rotation of the Ag unit cell about the Si [111] axis. It is intriguing that Ag nanoislands follow an epitaxial relationship with the Si(111) substrate in spite of the presence of a 2-3 nm thick oxide layer between Ag and Si. Apparently the short range order on the oxide surface influences the crystallographic orientation of the Ag nanoislands.Comment: 10 figure

Density-functional study of hydrogen chemisorption on vicinal Si(001) surfaces

Relaxed atomic geometries and chemisorption energies have been calculated for the dissociative adsorption of molecular hydrogen on vicinal Si(001) surfaces. We employ density-functional theory, together with a pseudopotential for Si, and apply the generalized gradient approximation by Perdew and Wang to the exchange-correlation functional. We find the double-atomic-height rebonded D_B step, which is known to be stable on the clean surface, to remain stable on partially hydrogen-covered surfaces. The H atoms preferentially bind to the Si atoms at the rebonded step edge, with a chemisorption energy difference with respect to the terrace sites of >sim 0.1 eV. A surface with rebonded single atomic height S_A and S_B steps gives very similar results. The interaction between H-Si-Si-H mono-hydride units is shown to be unimportant for the calculation of the step-edge hydrogen-occupation. Our results confirm the interpretation and results of the recent H_2 adsorption experiments on vicinal Si surfaces by Raschke and Hoefer described in the preceding paper.Comment: 13 pages, 8 figures, submitted to Phys. Rev. B. Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

A Cross-National Investigation of Hallucination-Like Experiences in 10 Countries: The E-CLECTIC Study

Hallucination-like experiences (HLEs) are typically defined as sensory perceptions in the absence of external stimuli. Multidimensional tools, able to assess different facets of HLEs, are helpful for a better characterization of hallucination proneness and to investigate the cross-national variation in the frequencies of HLEs. The current study set out to establish the validity, factor structure, and measurement invariance of the Launay-Slade Hallucinations Scale-Extended (LSHS-E), a tool to assess HLEs. A total of 4419 respondents from 10 countries were enrolled. Network analyses between the LSHS-E and the 3 dimensions of the Community Assessment of Psychic Experiences (CAPE) were performed to assess convergent and divergent validity of the LSHS-E. Confirmatory factor analysis was used to test its measurement invariance. The best fit was a 4-factor model, which proved invariant by country and clinical status, indicating cross-national stability of the hallucination-proneness construct. Among the different components of hallucination-proneness, auditory-visual HLEs had the strongest association with the positive dimension of the CAPE, compared with the depression and negative dimensions. Participants who reported a diagnosis of a mental disorder scored higher on the 4 LSHS-E factors. Small effect size differences by country were found in the scores of the 4 LSHS-E factors even after taking into account the role of socio-demographic and clinical variables. Due to its good psychometric properties, the LSHS-E is a strong candidate tool for large investigations of HLEs