The NIR structure of the barred galaxy NGC253 from VISTA

[abridged] We used J and Ks band images acquired with the VISTA telescope as part of the science verification to quantify the structures in the stellar disk of the barred Sc galaxy NGC253. Moving outward from the galaxy center, we find a nuclear ring within the bright 1 kpc diameter nucleus, then a bar, a ring with 2.9 kpc radius. From the Ks image we obtain a new measure of the deprojected length of the bar of 2.5 kpc. The bar's strength, as derived from the curvature of the dust lanes in the J-Ks image, is typical of weak bars. From the deprojected length of the bar, we establish the corotation radius (R_CR=3 kpc) and bar pattern speed (Omega_b = 61.3 km /s kpc), which provides the connection between the high-frequency structures in the disk and the orbital resonances induced by the bar. The nuclear ring is located at the inner Lindblad resonance. The second ring does not have a resonant origin, but it could be a merger remnant or a transient structure formed during an intermediate stage of the bar formation. The inferred bar pattern speed places the outer Lindblad resonance within the optical disk at 4.9 kpc, in the same radial range as the peak in the HI surface density. The disk of NGC253 has a down-bending profile with a break at R~9.3 kpc, which corresponds to about 3 times the scale length of the inner disk. We discuss the evidence for a threshold in star formation efficiency as a possible explanation of the steep gradient in the surface brightness profile at large radii. The NIR photometry unveils the dynamical response of the NGC253 stellar disk to its central bar. The formation of the bar may be related to the merger event that determined the truncation of stars and gas at large radii and the perturbation of the disk's outer edge.Comment: Accepted for publication in Astronomy & Astrphysics. High resolution pdf file is available at the following link: https://www.dropbox.com/s/4o4cofs1lyjrtpv/NGC253.pd

Efficient Symmetry Reduction and the Use of State Symmetries for Symbolic Model Checking

One technique to reduce the state-space explosion problem in temporal logic model checking is symmetry reduction. The combination of symmetry reduction and symbolic model checking by using BDDs suffered a long time from the prohibitively large BDD for the orbit relation. Dynamic symmetry reduction calculates representatives of equivalence classes of states dynamically and thus avoids the construction of the orbit relation. In this paper, we present a new efficient model checking algorithm based on dynamic symmetry reduction. Our experiments show that the algorithm is very fast and allows the verification of larger systems. We additionally implemented the use of state symmetries for symbolic symmetry reduction. To our knowledge we are the first who investigated state symmetries in combination with BDD based symbolic model checking

Randomized benchmarking of single and multi-qubit control in liquid-state NMR quantum information processing

Being able to quantify the level of coherent control in a proposed device implementing a quantum information processor (QIP) is an important task for both comparing different devices and assessing a device's prospects with regards to achieving fault-tolerant quantum control. We implement in a liquid-state nuclear magnetic resonance QIP the randomized benchmarking protocol presented by Knill et al (PRA 77: 012307 (2008)). We report an error per randomized $\frac{\pi}{2}$ pulse of $1.3 \pm 0.1 \times 10^{-4}$ with a single qubit QIP and show an experimentally relevant error model where the randomized benchmarking gives a signature fidelity decay which is not possible to interpret as a single error per gate. We explore and experimentally investigate multi-qubit extensions of this protocol and report an average error rate for one and two qubit gates of $4.7 \pm 0.3 \times 10^{-3}$ for a three qubit QIP. We estimate that these error rates are still not decoherence limited and thus can be improved with modifications to the control hardware and software.Comment: 10 pages, 6 figures, submitted versio

Experimental effects of mindfulness inductions on self-regulation: Systematic review and meta-analysis.

Self-regulation is the control of aspects of the self to allow pursuit of long-term goals, and it is proposed as a central pathway through which mindfulness may exert benefits on well-being. However, the effects of a single mindfulness induction on self-regulation are not clear, as there has been no comprehensive review of this evidence. The current review synthesized existing findings relating to the effect of a mindfulness induction delivered in a laboratory setting on measures of self-regulation. Twenty-seven studies were included and grouped according to 3 outcomes: regulation of experimentally induced negative affect (k = 15; meta-analysis), emotion-regulation strategies (k = 7) and executive functions (k = 9; narrative synthesis). A mindfulness induction was superior to comparison groups in enhancing the regulation of negative affect (d = -.28). Executive-function performance was enhanced only when the experimental design included an affect induction or when the outcome was sustained attention. The effect on emotion-regulation strategies was inconclusive, but with emerging evidence for an effect on rumination. Overall, the findings indicate that, in the form of an induction, mindfulness may have the most immediate effect on attention mechanisms rather than exerting cognitive changes in other domains, as are often reported outcomes of longer mindfulness training. Through effecting change in attention, emotion regulation of negative affect can be enhanced, and subsequently, executive-function performance more quickly restored. The interpretations of the findings are caveated with consideration of the low quality of many of the included study designs determined by the quality appraisal tool

A systematic review of the role of parents in the development of anxious cognitions in children

Anxious cognitions and parental behavior are important in the development of child anxiety. The current review aims to appraise the literature on the relationship between parental factors and chid anxious cognitions. Online database searches of PsycInfo, Scopus, ProQuest Dissertations and Web of Science were systematically searched using key terms related to 'parent', 'child', 'anxiety' and 'cognitions'. Included studies (N = 13) were quality assessed and study findings were appraised in line with cognitive behavioral frameworks of the parental pathways to the development of anxious cognitions in children. Reviewed studies confirmed that parental factors have a role in the development of their children's anxious cognitions by modelling fearful responses, reducing their child's autonomy, and indirectly via their own expectations about their child. Limitations of the literature are considered, including issues of measurement. Future research should consider multi-modal assessment of parental factors and examine parental behavior and child anxious cognitions in the context of real-life threatening events

Model Checking CTL is Almost Always Inherently Sequential

The model checking problem for CTL is known to be P-complete (Clarke, Emerson, and Sistla (1986), see Schnoebelen (2002)). We consider fragments of CTL obtained by restricting the use of temporal modalities or the use of negations---restrictions already studied for LTL by Sistla and Clarke (1985) and Markey (2004). For all these fragments, except for the trivial case without any temporal operator, we systematically prove model checking to be either inherently sequential (P-complete) or very efficiently parallelizable (LOGCFL-complete). For most fragments, however, model checking for CTL is already P-complete. Hence our results indicate that, in cases where the combined complexity is of relevance, approaching CTL model checking by parallelism cannot be expected to result in any significant speedup. We also completely determine the complexity of the model checking problem for all fragments of the extensions ECTL, CTL+, and ECTL+

United Kingdom: Citizenship education in the United Kingdom: comparing England, Northern Ireland, Scotland and Wales

Purpose: In this country case study the authors undertake a comparative analysis of citizenship education across the four nations of the UK. The curriculum and contexts in England, Scotland, Wales and Northern Ireland are first described. Then the article considers how each national example engages with fundamental expectations of citizenship education, specifically in relation to questions of citizenship status and the relationship between citizens and the state; political identity; and active citizenship processes. Approach: Drawing on the authors’ collective experience and insights into policy and practice in each nation, we started with a ‘generative conversation’ to identify key issues for inclusion in this case study. Findings: The article unearths a variety of constraints and problems, and situates these in a broader policyscape in which policy accretion and policy approximation generate a permissive culture, which has undermined the promise of citizenship education as an entitlement for all young people

Frequentist Evaluation of Group Sequential Clinical Trial Designs

Group sequential stopping rules are often used as guidelines in the monitoring of clinical trials in order to address the ethical and efficiency issues inherent in human testing of a new treatment or preventive agent for disease. Such stopping rules have been proposed based on a variety of different criteria, both scientific (e.g., estimates of treatment effect) and statistical (e.g., frequentist type I error, Bayesian posterior probabilities, stochastic curtailment). It is easily shown, however, that a stopping rule based on one of those criteria induces a stopping rule on all other criteria. Thus the basis used to initially define a stopping rule is relatively unimportant so long as the operating characteristics of the stopping rule are fully investigated. In this paper we describe how the frequentist operating characteristics of a particular stopping rule might be evaluated in order to ensure that the selected clinical trial design satisfies the constraints imposed by the many different disciplines represented by the clinical trial collaborators

Bayesian Evaluation of Group Sequential Clinical Trial Designs

Clincal trial designs often incorporate a sequential stopping rule to serve as a guide in the early termination of a study. When choosing a particular stopping rule, it is most common to examine frequentist operating characteristics such as type I error, statistical power, and precision of confi- dence intervals (Emerson, et al. [1]). Increasingly, however, clinical trials are designed and analyzed in the Bayesian paradigm. In this paper we describe how the Bayesian operating characteristics of a particular stopping rule might be evaluated and communicated to the scientific community. In particular, we consider a choice of probability models and a family of prior distributions that allows concise presentation of Bayesian properties for a specified sampling plan

Information-theoretic equilibration: the appearance of irreversibility under complex quantum dynamics

The question of how irreversibility can emerge as a generic phenomena when the underlying mechanical theory is reversible has been a long-standing fundamental problem for both classical and quantum mechanics. We describe a mechanism for the appearance of irreversibility that applies to coherent, isolated systems in a pure quantum state. This equilibration mechanism requires only an assumption of sufficiently complex internal dynamics and natural information-theoretic constraints arising from the infeasibility of collecting an astronomical amount of measurement data. Remarkably, we are able to prove that irreversibility can be understood as typical without assuming decoherence or restricting to coarse-grained observables, and hence occurs under distinct conditions and time-scales than those implied by the usual decoherence point of view. We illustrate the effect numerically in several model systems and prove that the effect is typical under the standard random-matrix conjecture for complex quantum systems.Comment: 15 pages, 7 figures. Discussion has been clarified and additional numerical evidence for information theoretic equilibration is provided for a variant of the Heisenberg model as well as one and two-dimensional random local Hamiltonian