Scalable designs for quantum computing with rare-earth-ion-doped crystals

Due to inhomogeneous broadening, the absorption lines of rare-earth-ion dopands in crystals are many order of magnitudes wider than the homogeneous linewidths. Several ways have been proposed to use ions with different inhomogeneous shifts as qubit registers, and to perform gate operations between such registers by means of the static dipole coupling between the ions. In this paper we show that in order to implement high-fidelity quantum gate operations by means of the static dipole interaction, we require the participating ions to be strongly coupled, and that the density of such strongly coupled registers in general scales poorly with register size. Although this is critical to previous proposals which rely on a high density of functional registers, we describe architectures and preparation strategies that will allow scalable quantum computers based on rare-earth-ion doped crystals.Comment: Submitted to Phys. Rev.

Risk factors for vulnerable youth in urban townships in South Africa: the potential contribution of reactive attachment disorder

Reactive attachment disorder (RAD) is a psychiatric disorder developing in early or middle childhood as a consequence of significant failures in the caregiving environment. RAD results in children failing to relate socially, either by exhibiting markedly inhibited behaviour or by indiscriminate social behaviour and is associated with significant socio-behavioural problems in the longer term. This study examined RAD in South Africa, a setting with high environmental risks. We recruited a sub-sample of 40 10-year-old children from a cohort enrolled during pregnancy for whom early attachment status was known. Children were purposefully selected to represent the four attachment categories using the data available on the strange situation procedure (SSP) at 18 months. The Manchester Child Attachment Story Task (MCAST) assessed current attachment and RAD was diagnosed using a standardised assessment package. A high proportion of the children (5/40% or 12.5%) fulfilled diagnostic criteria for RAD; all were boys and were displaying the disinhibited type. SSP classification at 18 months was not significantly associated with RAD symptoms at age of 10 years, while current MCAST classifications were. This suggests that children in this sample are at much higher risk of RAD than in high-income populations, and despite a fairly typical attachment distribution in this population at 18 months, RAD was evidenced in later childhood and associated with current attachment disorganisation. The strengths of this research include its longitudinal nature and use of diagnostic assessments. Given increasing evidence that RAD is relatively stable over time and introduces longer term socio-behavioural risks; the high rate of RAD in this sample (12.5%) highlights potential developmental threats to children in low- and middle-income countries (LMICs). Our results should be interpreted with caution given sample size and risk of selection bias. Further research is needed to confirm these findings

Costs and benefits of a subtype-specific surveillance system for identifying Escherichia coli O157:H7 outbreaks.

We assessed the societal costs and benefits of a subtype-specific surveillance system for identifying outbreak-associated Escherichia coli O157:H7 infections. Using data from Colorado, we estimated that if it averted five cases annually, the system would recover all its costs

Association between cognitive performance and cortical glucose metabolism in patients with mild Alzheimer's disease

Background: Neuronal and synaptic function in Alzheimer's disease (AD) is measured in vivo by glucose metabolism using positron emission tomography (PET). Objective: We hypothesized that neuronal activation as measured by PET is a more sensitive index of neuronal dysfunction than activity during rest. We investigated if the correlations between dementia severity as measured with the Mini Mental State Examination (MMSE) and glucose metabolism are an artifact of brain atrophy. Method: Glucose metabolism was measured using {[}F-18]fluorodeoxyglucose PET during rest and activation due to audiovisual stimulation in 13 mild to moderate AD patients (MMSE score >= 17). PET data were corrected for brain atrophy. Results: In the rest condition, glucose metabolism was correlated with the MMSE score primarily within the posterior cingulate and parietal lobes. For the activation condition, additional correlations were within the primary and association audiovisual areas. Most local maxima remained significant after correcting for brain atrophy. Conclusion: PET activity measured during audiovisual stimulation was more sensitive to functional alterations in glucose metabolism in AD patients compared to the resting PET. The association between glucose metabolism and MMSE score was not dependent on brain atrophy. Copyright (C) 2005 S. Karger AG, Basel

P092 improving postgraduate psychology students’ sleep and insomnia knowledge with a sleep education workshop

Abstract Introduction Trainee psychologists receive limited sleep and insomnia education during postgraduate study. This study examined the delivery of a sleep psychology training workshop for postgraduate psychology students and examined changes in sleep knowledge from pre- to post-workshop. Methods A 6-hour Sleep Psychology Workshop was delivered to postgraduate psychology students around Victoria. Online pre- and post-workshop questionnaires were used to evaluate changes in sleep psychology knowledge and collect feedback on the workshop. Results The participants were 187 students (82% female, M age = 32), most of whom were in their 5th year of psychology training (69%) and had not received any sleep education during their postgraduate studies at the date of the intervention (77%). Students’ sleep knowledge significantly improved after workshop completion (pre: 56% vs. post: 80% correct), t(107)= -21.41, p < .001. Students provided positive feedback about the workshop, with 96% rating the workshop as excellent/very good and 86% reporting that they would recommend the workshop to other postgraduate students. Overall, 94% of students agreed/strongly agreed that the sleep psychology workshop improved their confidence to manage sleep disturbances in their future psychology practice. Discussion Postgraduate psychology students require sleep and insomnia education. This study demonstrates that students’ sleep psychology knowledge can improve after a 6-hour sleep education and training workshop and provides initial positive feedback about the benefits of sleep and insomnia education for postgraduate students

Electron-Phonon Dynamics in an Ensemble of Nearly Isolated Nanoparticles

We investigate the electron population dynamics in an ensemble of nearly isolated insulating nanoparticles, each nanoparticle modeled as an electronic two-level system coupled to a single vibrational mode. We find that at short times the ensemble-averaged excited-state population oscillates but has a decaying envelope. At long times, the oscillations become purely sinusoidal about a ``plateau'' population, with a frequency determined by the electron-phonon interaction strength, and with an envelope that decays algebraically as t^-{1/2} We use this theory to predict electron-phonon dynamics in an ensemble of Y_2 O_3 nanoparticles.Comment: 11 pages, 3 figure

Mental health: Future challenges [Mental Capital and Wellbeing: Making the most of ourselves in the 21st century]

The aim of the Foresight Project on Mental Capital and Wellbeing (www.foresight.gov.uk) is to advise the Government on how to achieve the best possible mental development and mental wellbeing for everyone in the UK in the future. The starting point of the Project was to generate an understanding of the science of mental capital and wellbeing (MCW) and to develop a vision for how the size and nature of the challenges exposed by the Project could evolve over the next 20 years. To make this analysis tractable, the work was divided into five broad areas: Mental capital through life; Learning through life; Mental health; Wellbeing and work; and Learning difficulties. This report presents the findings for Mental health and draws upon a comprehensive assessment of the scientific state-of-the art: overall, around 80 reviews have been commissioned across the five areas

The Problem of Excess Reserves, Then and Now

Levy Institute scholars and conference participants. The purpose of the series is to disseminate ideas to and elicit comments from academics and professionals. Levy Economics Institute of Bard College, founded in 1986, is a nonprofit, nonpartisan, independently funded research organization devoted to public service. Through scholarship and economic research it generates viable, effective public policy responses to important economic problems that profoundly affect the quality of life in the United States and abroad

Tilted algebras and short chains of modules

We provide an affirmative answer for the question raised almost twenty years ago concerning the characterization of tilted artin algebras by the existence of a sincere finitely generated module which is not the middle of a short chain

Benchmark Calculations of Electron Impact Electronic Excitation of the Hydrogen Molecule

We present benchmark integrated and differential cross-sections for electron collisions with H$_2$ using two different theoretical approaches, namely, the R-matrix and molecular convergent close-coupling (MCCC). This is similar to comparative studies conducted on electron-atom collisions for H, He and Mg. Electron impact excitation to the $b \ ^3\Sigma_u^+$, $a \ ^3\Sigma_g^+$, $B \ ^1\Sigma_u^+$,$c \ ^3\Pi_u$,$EF \ ^1\Sigma_g^+$,$C \ ^1\Pi_u$,$e \ ^3\Sigma_u^+$,$h \ ^3\Sigma_g^+$,$B' \ ^1\Sigma_u^+$and$d \ ^3\Pi_u$excited electronic states are considered. Calculations are presented in both the fixed nuclei and adiabatic nuclei approximations, where the latter is shown only for the$b \ ^3\Sigma_u^+$ state. Good agreement is found for all transitions presented. Where available, we compare with existing experimental and recommended data.Comment: 21 pages, 25 figure