Understanding thio-effects in simple phosphoryl systems : role of solvent effects and nucleophile charge.

Recent experimental work (J. Org. Chem., 2012, 77, 5829) demonstrated pronounced differences in measured thio-effects for the hydrolysis of (thio)phosphodichloridates by water and hydroxide nucleophiles. In the present work, we have performed detailed quantum chemical calculations of these reactions, with the aim of rationalizing the molecular bases for this discrimination. The calculations highlight the interplay between nucleophile charge and transition state solvation in SN2(P) mechanisms as the basis of these differences, rather than a change in mechanism

Predictive learning, prediction errors, and attention: evidence from event-related potentials and eye tracking

Prediction error (‘‘surprise’’) affects the rate of learning: We learn more rapidly about cues for which we initially make incorrect predictions than cues for which our initial predictions are correct. The current studies employ electrophysiological measures to reveal early attentional differentiation of events that differ in their previous involvement in errors of predictive judgment. Error-related events attract more attention, as evidenced by features of event-related scalp potentials previously implicated in selective visual attention (selection negativity, augmented anterior N1). The earliest differences detected occurred around 120 msec after stimulus onset, and distributed source localization (LORETA) indicated that the inferior temporal regions were one source of the earliest differences. In addition, stimuli associated with the production of prediction errors show higher dwell times in an eyetracking procedure. Our data support the view that early attentional processes play a role in human associative learning

The Effect of the Hall Term on the Nonlinear Evolution of the Magnetorotational Instability: I. Local Axisymmetric Simulations

The effect of the Hall term on the evolution of the magnetorotational instability (MRI) in weakly ionized accretion disks is investigated using local axisymmetric simulations. First, we show that the Hall term has important effects on the MRI when the temperature and density in the disk is below a few thousand K and between 10^13 and 10^18 cm^{-3} respectively. Such conditions can occur in the quiescent phase of dwarf nova disks, or in the inner part (inside 10 - 100 AU) of protoplanetary disks. When the Hall term is important, the properties of the MRI are dependent on the direction of the magnetic field with respect to the angular velocity vector \Omega. If the disk is threaded by a uniform vertical field oriented in the same sense as \Omega, the axisymmetric evolution of the MRI is an exponentially growing two-channel flow without saturation. When the field is oppositely directed to \Omega, however, small scale fluctuations prevent the nonlinear growth of the channel flow and the MRI evolves into MHD turbulence. These results are anticipated from the characteristics of the linear dispersion relation. In axisymmetry on a field with zero-net flux, the evolution of the MRI is independent of the size of the Hall term relative to the inductive term. The evolution in this case is determined mostly by the effect of ohmic dissipation.Comment: 31 pages, 3 tables, 12 figures, accepted for publication in ApJ, postscript version also available from http://www.astro.umd.edu/~sano/publications

External and internal noise surveys of London primary schools

Internal and external noise surveys have been carried out around schools in London, UK, to provide information on typical levels and sources to which children are exposed while at school. Noise levels were measured outside 142 schools, in areas away from flightpaths into major airports. 86% of the schools surveyed were exposed to noise from road traffic, the average external noise level outside a school being 57 dB LAeq. Detailed internal noise surveys have been carried out in 140 classrooms in 16 schools, together with classroom observations. It was found that noise levels inside classrooms depend upon the activities in which the children are engaged, with a difference of 20 dB LAeq between the 'quietest' and 'noisiest' activities. The average background noise level in classrooms exceeds the level recommended in current standards. The number of children in the classroom was found to affect noise levels. External noise influenced internal noise levels only when children were engaged in the quietest classroom activities. The effects of the age of the school buildings and types of window upon internal noise were examined but results were inconclusive

Dust sedimentation and self-sustained Kelvin-Helmholtz turbulence in protoplanetary disk mid-planes. I. Radially symmetric simulations

We perform numerical simulations of the Kelvin-Helmholtz instability in the mid-plane of a protoplanetary disk. A two-dimensional corotating slice in the azimuthal--vertical plane of the disk is considered where we include the Coriolis force and the radial advection of the Keplerian rotation flow. Dust grains, treated as individual particles, move under the influence of friction with the gas, while the gas is treated as a compressible fluid. The friction force from the dust grains on the gas leads to a vertical shear in the gas rotation velocity. As the particles settle around the mid-plane due to gravity, the shear increases, and eventually the flow becomes unstable to the Kelvin-Helmholtz instability. The Kelvin-Helmholtz turbulence saturates when the vertical settling of the dust is balanced by the turbulent diffusion away from the mid-plane. The azimuthally averaged state of the self-sustained Kelvin-Helmholtz turbulence is found to have a constant Richardson number in the region around the mid-plane where the dust-to-gas ratio is significant. Nevertheless the dust density has a strong non-axisymmetric component. We identify a powerful clumping mechanism, caused by the dependence of the rotation velocity of the dust grains on the dust-to-gas ratio, as the source of the non-axisymmetry. Our simulations confirm recent findings that the critical Richardson number for Kelvin-Helmholtz instability is around unity or larger, rather than the classical value of 1/4Comment: Accepted for publication in ApJ. Some minor changes due to referee report, most notably that the clumping mechanism has been identified as the streaming instability of Youdin & Goodman (2005). Movies of the simulations are still available at http://www.mpia.de/homes/johansen/research_en.ph

Medication supply for people evacuated during disasters.

© 2015 Chinese Cochrane Center, West China Hospital of Sichuan University and Wiley Publishing Asia Pty Ltd.Medication loss is a major problem in disaster settings, and it is crucial for patients to bring their medication and healthcare items with them when they leave their homes during an evacuation. This article is based on a systematic literature review on medication loss, the objectives of which were to identify the extent and implications of medication loss, to identify the burden of prescription refill, and to make recommendations on effective preparedness. The review revealed that medication loss, prescription loss and refills, and the loss of medical aids are a significant burden on the medical relief teams. The medical aids are not limited to drugs, but include routine medications, medical/allergy records, devices for specific care and daily life, and emergency medications. One possible solution is to make a personal emergency pack and for people to carry this with them at all times. To ensure that patients are adequately prepared, stakeholders, especially health professionals, need to be actively involved in the preparation plans. Since our findings have little impact on disaster risk reduction unless shared broadly, we are now taking actions to spread our findings, such as presenting in conferences and via posters, in order to raise awareness among patients and healthcare professionals. As part of these activities, our findings were presented at the Evidence Aid Symposium on 20 September 2014, at Hyderabad, India

Disaster-driven evacuation and medication loss: a systematic literature review

AIM: The aim of this systematic literature review was to identify the extent and implications of medication loss and the burden of prescription refill on medical relief teams following extreme weather events and other natural hazards. METHOD: The search strategy followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Key health journal databases (Medline, Embase, PsycINFO, Maternity and Infant Care, and Health Management Information Consortium (HMIC)) were searched via the OvidSP search engine. Search terms were identified by consulting MeSH terms. The inclusion criteria comprised articles published from January 2003 to August 2013, written in English and containing an abstract. The exclusion criteria included abstracts for conferences or dissertations, book chapters and articles written in a language other than English. A total of 70 articles which fulfilled the inclusion criteria were included in this systematic review. RESULTS: All relevant information was collated regarding medication loss, prescription loss and refills, and medical aids loss which indicated a significant burden on the medical relief teams. Data also showed the difficulty in filling prescriptions due to lack of information from the evacuees. People with chronic conditions are most at risk when their medication is not available. This systematic review also showed that medical aids such as eye glasses, hearing aids as well as dental treatment are a high necessity among evacuees. DISCUSSION: This systematic review revealed that a considerable number of patients lose their medication during evacuation, many lose essential medical aids such as insulin pens and many do not bring prescriptions with them when evacuated.. Since medication loss is partly a responsibility of evacuees, understanding the impact of medication loss may lead to raising awareness and better preparations among the patients and health care professionals. People who are not prepared could have worse outcomes and many risk dying when their medication is not available