Trapped-ion quantum error-correcting protocols using only global operations

Quantum error-correcting codes are many-body entangled states that are prepared and measured using complex sequences of entangling operations. Each element of such an entangling sequence introduces noise to delicate quantum information during the encoding or reading out of the code. It is important therefore to find efficient entangling protocols to avoid the loss of information. Here we propose an experiment that uses only global entangling operations to encode an arbitrary logical qubit to either the five-qubit repetition code or the five-qubit code, with a six-ion Coulomb crystal architecture in a Penning trap. We show that the use of global operations enables us to prepare and read out these codes using only six and ten global entangling pulses, respectively. The proposed experiment also allows the acquisition of syndrome information during readout. We provide a noise analysis for the presented protocols, estimating that we can achieve a six-fold improvement in coherence time with noise as high as $\sim 1\%$ on each entangling operation.Comment: 7 pages, 4 figures, published version, comments are welcom

Optimal body size with respect to maximal speed for the yellow-spotted monitor lizard (Varanus panoptes; varanidae)

Studies of locomotor performance often link variation in morphology with ecology. While maximum sprint speed is a commonly used performance variable, the absolute limits for this performance trait are not completely understood. Absolute maximal speed has often been shown to increase linearly with body size, but several comparative studies covering a large range of body sizes suggest that maximal speed does not increase indefinitely with body mass but rather reaches an optimum after which speed declines. Because of the comparative nature of these studies, it is difficult to determine whether this decrease is due to biomechanical constraints on maximal speed or is a consequence of phylogenetic inertia or perhaps relaxed selection for lower maximal speed at large body size. To explore this issue, we have examined intraspecific variations in morphology, maximal sprint speed, and kinematics for the yellowspotted monitor lizard Varanus panoptes, which varied in body mass from 0.09 to 5.75 kg. We show a curvilinear relationship between body size and absolute maximal sprint speed with an optimal body mass with respect to speed of 1.245 kg. This excludes the phylogenetic inertia hypothesis, because this effect should be absent intraspecifically, while supporting the biomechanical constraints hypothesis. The relaxed selection hypothesis cannot be excluded if there is a size-based behavioral shift intraspecifically, but the biomechanical constraints hypothesis is better supported from kinematic analyses. Kinematic measurements of hind limb movement suggest that the distance moved by the body during the stance phase may limit maximum speed. This limit is thought to be imposed by a decreased ability of the bones and muscles to support body mass for larger lizards

Conceptualisations of children’s wellbeing at school: the contribution of recognition theory

A large study in Australian schools aimed to elucidate understandings of ‘wellbeing’ and of factors in school life that contribute to it. Students and teachers understood wellbeing primarily, and holistically, in terms of interpersonal relationships, in contrast to policy documents which mainly focused on ‘problem areas’ such as mental health. The study also drew on recognition theory as developed by the social philosopher Axel Honneth. Results indicate that recognition theory may be useful in understanding wellbeing in schools, and that empirical research in schools may give rise to further questions regarding theory

Methods for Estimating Environmental Effects and Constraints on NexGen: High Density Case Study

This document provides a summary of the current methods developed by Metron Aviation for the estimate of environmental effects and constraints on the Next Generation Air Transportation System (NextGen). This body of work incorporates many of the key elements necessary to achieve such an estimate. Each section contains the background and motivation for the technical elements of the work, a description of the methods used, and possible next steps. The current methods described in this document were selected in an attempt to provide a good balance between accuracy and fairly rapid turn around times to best advance Joint Planning and Development Office (JPDO) System Modeling and Analysis Division (SMAD) objectives while also supporting the needs of the JPDO Environmental Working Group (EWG). In particular this document describes methods applied to support the High Density (HD) Case Study performed during the spring of 2008. A reference day (in 2006) is modeled to describe current system capabilities while the future demand is applied to multiple alternatives to analyze system performance. The major variables in the alternatives are operational/procedural capabilities for airport, terminal, and en route airspace along with projected improvements to airframe, engine and navigational equipment

Operational reliability assessment of the GEOS A spacecraft

Decision theory application to GEOS A spacecraft operational reliability assessmen

Assessing wellbeing at school entry using the strengths and difficulties questionnaire: professional perspectives

<p>Background: Emotional and behavioural disorders in early childhood are related to poorer academic attainment and school engagement, and difficulties already evident at the point of starting school can affect a child’s later social and academic development. Successful transfer from pre-school settings to primary education is helped by communication between pre-school staff and primary school teachers. Typically, in Scotland, pre-school establishments prepare individual profiles of children before they start school around the age of five years, highlighting their strengths and development needs, for transfer to primary schools. There is, however, no consistent approach to the identification of potential social, emotional and behavioural problems. In 2010, in one local authority area in Scotland, the Strengths and Difficulties Questionnaire (SDQ) was introduced for children about to start school as a routine, structured, component of the transition process to help teachers plan support arrangements for classes and individual children. The SDQ assesses emotional, conduct, hyperactivity/ inattention and peer-relationship problems as well as pro-social behaviour. In order to be an effective means of communicating social and emotional functioning, the use of instruments such as the SDQ needs to be practicable. Finding out the views of pre-school education staff with experience of assessing children using the SDQ was, therefore, essential to establish its future utility.</p> <p>Aim: The purpose of this study was to explore the views of pre-school education staff about assessing social and emotional wellbeing of children at school entry using the SDQ. The objectives were to examine the opinions of pre-school workers about completing the SDQ and to elicit their thoughts on the value of doing this and their perceptions of the usefulness of the information collected.</p> <p>Method: Pre-school establishments were approached using a purposive sampling strategy in order to achieve a mix of local authority (n=14) and ‘partnership’ establishments (n=8) as well as different socio-economic areas. Semi-structured interviews (n=25) were conducted with pre-school head teachers (n=14) and child development officers (n=11) in order to explore the process of completing the SDQ along with perceptions of its value. The interviews were transcribed verbatim and analysed thematically.</p> <p>Results: In general, staff in pre-school establishments viewed the use of the SDQ positively. It was seen as a chance to highlight the social and emotional development of children rather than just their academic or educational ability. Most felt that the SDQ had not identified anything they did not already know about a child. A minority, nevertheless, suggested that a previously unrecognised potential difficulty was brought to light, most commonly emotional problems. Completing the SDQ was felt to be relatively straightforward even though the staff felt under pressure from competing priorities. Concerns were, however, raised about the potential of labelling a child at an early stage of formal education.</p> <p>Conclusion: The findings from this small scale study suggest that, from the point of view of pre-school education staff, it is feasible to assess children systematically for social and behavioural problems as part of the routine transition process at school entry.</p&gt

No Association of Obesity and Type 2 Diabetes Mellitus Related Genetic Variants With Colon Cancer

Background: Obesity and type 2 diabetes mellitus (T2D) are known risk factors for colon cancer. Recent reports from a number of genome wide association studies (GWAS) have identified several single nucleotide polymorphisms (SNPs) associated with obesity and T2D. Here we tested the hypothesis that these SNPs may also be associated with risk of colon cancer. Methods: We genotyped nine SNPs reported in GWAS of obesity and/or T2D, including SNPs in HHEX, KCNJ11, SLC30A8, FTO, CDKN2, CDKAL1, TCF2, and the rs9300039 SNP in an intergenic region, in 561 colon cancer cases and 721 population controls. Results: None of these SNPs were statistically significantly associated with colon cancer in our sample. Conclusions: Overall, these results suggest that these obesity and T2D genetic susceptibility loci are unlikely to influence the risk of colon cancer

Directional hydrophone clusters reveal evasive responses of small cetaceans to disturbance during construction at offshore windfarms

This study was funded by Moray Offshore Wind Farm (East) Ltd.Mitigation measures to disperse marine mammals prior to pile-driving include acoustic deterrent devices and piling soft starts, but their efficacy remains uncertain. We developed a self-contained portable hydrophone cluster to detect small cetacean movements from the distributions of bearings to detections. Using an array of clusters within 10 km of foundation pile installations, we tested the hypothesis that harbour porpoises (Phocoena phocoena) respond to mitigation measures at offshore windfarm sites by moving away. During baseline periods, porpoise movements were evenly distributed in all directions. By contrast, animals showed significant directional movement away from sound sources during acoustic deterrent device use and piling soft starts. We demonstrate that porpoises respond to measures aimed to mitigate the most severe impacts of construction at offshore windfarms by swimming directly away from these sound sources. Portable directional hydrophone clusters now provide opportunities to characterize responses to disturbance sources across a broad suite of habitats and contexts.Publisher PDFPeer reviewe