Retrodiction as a tool for micromaser field measurements

We use retrodictive quantum theory to describe cavity field measurements by successive atomic detections in the micromaser. We calculate the state of the micromaser cavity field prior to detection of sequences of atoms in either the excited or ground state, for atoms that are initially prepared in the excited state. This provides the POM elements, which describe such sequences of measurements.Comment: 20 pages, 4(8) figure

Weak Values and Continuous-Variable Entanglement Concentration

We demonstrate a general weak measurement model which allows Gaussian preserving entanglement concentration of the two mode squeezed vacuum. The power of this simple and elegant protocol is through the constraints it places on possible ancilla states and measurement strategies that will allow entanglement concentration. In particular, it is shown how previously discovered protocols of this kind emerge as special examples of the general model described here. Finally, as evidence of its utility, we use it to provide another novel example of such a protocol.Comment: 4 pages, 1 figure, Final version to appear in Phys. Rev.

Adaptive foveated single-pixel imaging with dynamic super-sampling

As an alternative to conventional multi-pixel cameras, single-pixel cameras enable images to be recorded using a single detector that measures the correlations between the scene and a set of patterns. However, to fully sample a scene in this way requires at least the same number of correlation measurements as there are pixels in the reconstructed image. Therefore single-pixel imaging systems typically exhibit low frame-rates. To mitigate this, a range of compressive sensing techniques have been developed which rely on a priori knowledge of the scene to reconstruct images from an under-sampled set of measurements. In this work we take a different approach and adopt a strategy inspired by the foveated vision systems found in the animal kingdom - a framework that exploits the spatio-temporal redundancy present in many dynamic scenes. In our single-pixel imaging system a high-resolution foveal region follows motion within the scene, but unlike a simple zoom, every frame delivers new spatial information from across the entire field-of-view. Using this approach we demonstrate a four-fold reduction in the time taken to record the detail of rapidly evolving features, whilst simultaneously accumulating detail of more slowly evolving regions over several consecutive frames. This tiered super-sampling technique enables the reconstruction of video streams in which both the resolution and the effective exposure-time spatially vary and adapt dynamically in response to the evolution of the scene. The methods described here can complement existing compressive sensing approaches and may be applied to enhance a variety of computational imagers that rely on sequential correlation measurements.Comment: 13 pages, 5 figure

Bounds on the lightest Higgs boson mass with three and four fermion generations

We present lower bounds on the Higgs boson mass in the Standard Model with three and four fermion generations SM(3,4), as well as upper bounds on the lightest Higgs boson mass in the minimal supersymmetric extension of the SM with three and four generations MSSM(3,4). Our analysis utilizes the SM(3,4) renormalization-group-improved one-loop effective potential of the Higgs boson to find the upper bounds on the Higgs mass in the MSSM(3,4) while the lower bounds in the SM(3,4) are derived from considerations of vacuum stability. All the bounds increase as the degenerate fourth generation mass increases, providing more room in theory space that respects the increasing experimental lower limit of the Higgs mass.Comment: 24 pages, 10 figures, Some additional discussion added. Final version to be published in International Journal of Modern Physics

Plasma homocyst(e)ine concentration, but not MTHFR genotype, is associated with variation in carotid plaque area

Background and Purpose - Elevated plasma homocyst(e)ine [H(e)] concentration is associated with premature atherosclerosis. A common cause of elevated plasma H(e) concentration is a thermolabile mutation (677T) in the gene encoding methylenetetrahydrofolate reductase (MTHFR). We sought to determine whether plasma H(e) concentration or MTHFR genotype would be more strongly associated with carotid plaque area (CPA), a potential intermediate phenotype of atherosclerosis. Methods - In 307 subjects who were ascertained through a premature atherosclerosis clinic, we measured CPA with 2- dimensional ultrasound and also determined traditional atherosclerosis risk factors, in addition to plasma H(e) concentration and MTHFR genotypes. Results - We found that the frequency of the MTHFR 677T allele was 0.363 in this sample. Mean plasma H(e) concentration was significantly higher in 677T/T homozygotes than in 677T/C heterozygotes and 677C/C homozygotes (17.1±13.7 versus 13.5±6.1 versus 12.6±5.9 μmol/L, respectively, P\u3c0.001). Analysis of variance showed that CPA was significantly associated with age, sex, smoking, diabetes, hypertension, and hyperlipidemia (each P\u3c0.05). When plasma H(e) concentration was included in the model, it was significantly associated with CPA (P\u3c0.05). However, when the MTHFR genotype was included in the model, it was not associated with CPA (P=0.50). Furthermore, there was a significant correlation of CPA with plasma H(e) (r=0.23, P\u3c0.0001). However, the mean CPA did not differ between subjects according to genotype. Conclusions - Thus, plasma H(e), but not MTHFR genotype, is significantly associated with carotid atherosclerosis, suggesting that the biochemical test may be sufficient to identify patients who may be at increased risk of atherosclerosis through this mechanism

Examining \u3cem\u3eDSM\u3c/em\u3e Criteria for Trichotillomania in A Dimensional Framework: Implications for \u3cem\u3eDSM-5\u3c/em\u3e And Diagnostic Practice

Background: Diagnosis of Trichotillomania (TTM) requires meeting several criteria that aim to embody the core pathology of the disorder. These criteria are traditionally interpreted monothetically, in that they are all equally necessary for diagnosis. Alternatively, a dimensional conceptualization of psychopathology allows for examination of the relatedness of each criterion to the TTM latent continuum. Objectives: First, to examine the ability of recently removed criteria (B and C) to identify the latent dimensions of TTM psychopathology, such that they discriminate between individuals with low and high degrees of hair pulling severity. Second, to determine the impact of removing criteria B and C on the information content of remaining diagnostic criteria. Third, to determine the psychometric properties of remaining TTM diagnostic criteria that remain largely unchanged in DSM-5; that is, whether they measure distinct or overlapping levels of TTM psychopathology. Fourth, to determine whether information content derived from diagnostic criteria aid in the prediction of disease trajectory (i.e., can relapse propensity be predicted from criteria endorsement patterns). Method: Statistics derived from Item Response Theory were used to examine diagnostic criteria endorsement in 91 adults with TTM who underwent psychotherapy. Results: The removal of two criteria in DSM-5 and psychometric validity of remaining criteria was supported. Additionally, individual trait parameters were used to predict treatment progress, uncovering predictive power where none previously existed. Conclusions: Diagnostic criteria for TTM should be examined in dimensional models, which allow for nuanced and sensitive measurement of core symptomology in treatment contexts

ROYALE: A Framework for Universally Composable Card Games with Financial Rewards and Penalties Enforcement

While many tailor made card game protocols are known, the vast majority of those suffer from three main issues: lack of mechanisms for distributing financial rewards and punishing cheaters, lack of composability guarantees and little flexibility, focusing on the specific game of poker. Even though folklore holds that poker protocols can be used to play any card game, this conjecture remains unproven and, in fact, does not hold for a number of protocols (including recent results). We both tackle the problem of constructing protocols for general card games and initiate a treatment of such protocols in the Universal Composability (UC) framework, introducing an ideal functionality that captures general card games constructed from a set of core card operations. Based on this formalism, we introduce Royale, the first UC-secure general card games which supports financial rewards/penalties enforcement. We remark that Royale also yields the first UC-secure poker protocol. Interestingly, Royale performs better than most previous works (that do not have composability guarantees), which we highlight through a detailed concrete complexity analysis and benchmarks from a prototype implementation

A reverse pathway? Actual and perceived skill proficiency and physical activity

Purpose: Motor skills are considered a prerequisite to physical activity, yet the relationship may be reciprocal and perceived sports competence might mediate associations.Methods: In 2006/2007, 215 adolescents completed motor skill proficiency (Get Skilled Get Active), perceived sport competence (Physical Self-Perception Profile) and physical activity assessments (Adolescent Physical Activity Recall Questionnaire) as part of the Physical Activity and Skills Study. Using AMOS (Version 7.0), reciprocal relationships were examined between motor skill (object control and locomotor) and moderate to vigorous physical activity (MVPA). Both models were then run in different versions to understand the role of perceived sports competence as a potential mediator. Results: Mean age was 16.4 yr (SD = 0.6), 51.6% (111/215) were females. A reciprocal relationship between object control and MVPA and a one-way relationship from MVPA to locomotor skill was found. When perceived sports competence was examined as a mediator, the best-fitting model versions explained 16% (R&sup2; = 0.16)MVPA variation, and 30% object control (R&sup2; = 0.30), and 12% locomotor skill variation (R&sup2; = 0.12) (reverse relationship). Perceived sports competence partially mediates the relationship between object control proficiency and physical activity for both directions and fully mediates the relationship between physical activity and locomotor skill; but only when locomotor skill is the outcome.Conclusions: If the relationship between object control skill and physical activity is viewed as a &lsquo;&lsquo;positive feedback loop,&rsquo;&rsquo; skill development and increasing physical activity should simultaneously be targeted in physical activity interventions. Increasing perceived sport competence should also be an intervention focus.<br /

Master Equation for Retrodiction of Quantum Communication Signals

We derive the master equation that governs the evolution of the measured state backwards in time in an open system. This allows us to determine probabilities for a given set of preparation events from the results of subsequent measurements, which has particular relevance to quantum communication.Comment: 14 pages, no figure