Methylthiolate-induced reconstruction of Ag(1 1 1): A medium energy ion scattering study

Medium energy ion scattering (MEIS), using 100 keV H+ incident ions, has been used to investigate the structure of the Ag(1 1 1)(√7 × √7)R19° –CH3S surface phase. The results provide the first direct evidence that this structure does involve substantial reconstruction of the Ag surface layer. The measured absolute scattered ion yields and blocking curves are in generally good agreement with a specific structural model of the surface based on a reconstructed layer containing 3/7 ML Ag atoms, previously suggested on the basis of scanning tunnelling microscopy (STM) and normal incidence X-ray standing wave (NIXSW) studies. However, the MEIS data indicate that any rumpling of the thiolate layer, is small, and probably 0.2 Å. This value is smaller than the amplitude suggested in the STM and NIXSW studies, but could be entirely consistent with the earlier experimental data

A gauge model for quantum mechanics on a stratified space

In the Hamiltonian approach on a single spatial plaquette, we construct a quantum (lattice) gauge theory which incorporates the classical singularities. The reduced phase space is a stratified K\"ahler space, and we make explicit the requisite singular holomorphic quantization procedure on this space. On the quantum level, this procedure furnishes a costratified Hilbert space, that is, a Hilbert space together with a system which consists of the subspaces associated with the strata of the reduced phase space and of the corresponding orthoprojectors. The costratified Hilbert space structure reflects the stratification of the reduced phase space. For the special case where the structure group is $\mathrm{SU}(2)$, we discuss the tunneling probabilities between the strata, determine the energy eigenstates and study the corresponding expectation values of the orthoprojectors onto the subspaces associated with the strata in the strong and weak coupling approximations.Comment: 38 pages, 9 figures. Changes: comments on the heat kernel and coherent states have been adde

Multivariate analysis of 1.5 million people identifies genetic associations with traits related to self-regulation and addiction

Behaviors and disorders related to self-regulation, such as substance use, antisocial behavior and attention-deficit/hyperactivity disorder, are collectively referred to as externalizing and have shared genetic liability. We applied a multivariate approach that leverages genetic correlations among externalizing traits for genome-wide association analyses. By pooling data from ~1.5 million people, our approach is statistically more powerful than single-trait analyses and identifies more than 500 genetic loci. The loci were enriched for genes expressed in the brain and related to nervous system development. A polygenic score constructed from our results predicts a range of behavioral and medical outcomes that were not part of genome-wide analyses, including traits that until now lacked well-performing polygenic scores, such as opioid use disorder, suicide, HIV infections, criminal convictions and unemployment. Our findings are consistent with the idea that persistent difficulties in self-regulation can be conceptualized as a neurodevelopmental trait with complex and far-reaching social and health correlates

Book Reviews

Book Review 1Book Title: Gastroenterological procedures: Manual of Gastroenterologic ProceduresBook Author: D.A. Drossman (Ed,)3rd ed. Pp. xv + 288. illustrated. New York: Raven Press. 1992.Book Review 2Book Title: Safety in diagnostic ultrasound: Exposure Criteria for Medical Diagnostic Ultrasound: I. Criteria Based on Thennal MechanismsBook Author: NCRP Report No. 113Pp. xv + 278. Illustrated. Bethesda MD: NCRP. 1992.Book Review 3Book Title: Knee arthroplasty: Total Knee ArthroplastyBook Author: James A. Rand (Ed.)pp. xiv + 464. illustrated. New York: Raven Press. 1992.Book Review 4Book Title: Drug-induced skin changes: Cutaneous Drug Reactions. An Integral Synopsis of Today's Systemic DrugsBook Authors: K. Zürcher & A. Krebs (Eds.)2nd Ed. pp. viii +570. Basel: Karger. 1992Book Review 5Book Title: Rabies WHO Expert Couunittee on Rabies: 8th ReportBook Author: WHOTechnical Report Series No. 824. Pp. vii + 84. Geneva: WHO. 1992.Book Review 6Book Title: Entomology and malaria. Entomological Field Techniques for Malaria ControlBook Author: WHOpp. 77. Geneva: WHO. 1992.Book Review 7Book Title: Handbook of PCVC. Handbook of Percutaneous Central Venous CatheterisationBook Authors: M. Rosen, P. Lano & S. Nig (Eds.)2nd Ed. pp. viii + 249. illustrated. Kent: Harcourt Brace and Jovanovich. 1992Book Review 8Book Title: HIV/AIDS resource directory: Resource Directory for HIV and AIDSBook Authors: Stewart Harris & Geoffrey Taylor (Eds.)83 + iv. 1992.Book Review 9Book Title: Laparoscopic surgery: Atlas of Laparoscopic SurgeryBook Authors:  E. J. Reddick, with W. B. Say & J. D. Corbitt (Eds.)Pp. ix + 116. illustrated. New York: Raven Press. 1992Book Review 10Book Title: Medical history. The illustrated History of MedicineBook Author:  Jean-Charles SourniaPp. 585. Illustrated. London: Harold Starke. 1992. (Distributed by Medical Association of South Africa, Private Bag XI, Pinelands 7430).Book Review 11Book Title: Plants in Cardiology. Plants in Cardiology Book Author: A. HollmanPp. vii + 40. Illustrated. London: BMJ. 1992.Book Review 12Book Title: Fraud in medical research. Fraud and Misconduct in Medical ResearchBook Authors: Stephen Lock & Frank Wells (Eds.)Pp. xi + 202. London: BMJ. 1993.Book Review 13Book Title: Anaesthesiology in emergencies Bailliere's Clinical Anaesthesiology: Emergency Medicine and the AnaesthetistBook Authors: H.H. Delooz (Ed.)Pp. xi + 212. Illustrated.London: Bailliere Tindall. 1992.Book Review 14Book Title: BMJ literary extracts. Soundings from BMJ ColunmistsBook Author: Ruth Holland (Ed.)Pp. xi + 89. London: BMJ 1992.Book Review 15Book Title: Chest imaging. Atlas of Chest Imaging: Correlated Anatomy with MRI and CTBook Authors: Marvin Wagner & Thomas L. Lawson (Eds.)Pp. ix + 134. lllustrated. New York: Raven Press. 1992.Book Review 16Book Title: Knee Meniscus: Basic and Clinical FoundationsBook Authors: Van C. Mow, Steven P. Amoczky & Douglas W. Jackson (Eds.)Pp. xi + 190. Illustrated. New York: Raven Press. 1992Book Review 17Book Title: Cryptorchidism. Descent of the TestisBook Authors: John M. Hutson & Spencer W. BeasleyPp. 187. Price: Illustrated. London: Edward Arnold. 1992.Book Review 18Book Title: Radiosurgery: Baseline and TrendsBook Authors: L. SteinerPp. xiv + 302. Illustrated. New York: Raven Press. 1992

Galaxy and mass assembly (GAMA): colour- and luminosity-dependent clustering from calibrated photometric redshifts

We measure the two-point angular correlation function of a sample of 4289 223 galaxies with r < 19.4 mag from the Sloan Digital Sky Survey (SDSS) as a function of photometric redshift, absolute magnitude and colour down to Mr − 5 log h = −14 mag. Photometric redshifts are estimated from ugriz model magnitudes and two Petrosian radii using the artificial neural network package ANNz, taking advantage of the Galaxy And Mass Assembly (GAMA) spectroscopic sample as our training set. These photometric redshifts are then used to determine absolute magnitudes and colours. For all our samples, we estimate the underlying redshift and absolute magnitude distributions using Monte Carlo resampling. These redshift distributions are used in Limber's equation to obtain spatial correlation function parameters from power-law fits to the angular correlation function. We confirm an increase in clustering strength for sub-L* red galaxies compared with ∼L* red galaxies at small scales in all redshift bins, whereas for the blue population the correlation length is almost independent of luminosity for ∼L* galaxies and fainter. A linear relation between relative bias and log luminosity is found to hold down to luminosities L ∼ 0.03L*. We find that the redshift dependence of the bias of the L* population can be described by the passive evolution model of Tegmark & Peebles. A visual inspection of a random sample from our r < 19.4 sample of SDSS galaxies reveals that about 10 per cent are spurious, with a higher contamination rate towards very faint absolute magnitudes due to over-deblended nearby galaxies. We correct for this contamination in our clustering analysis