Carleton University

About: Carleton University is a education organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 15852 authors who have published 39650 publications receiving 1106610 citations.

Intolerance of uncertainty, appraisals, coping, and anxiety: The case of the 2009 H1N1 pandemic

Abstract: Objectives Although ambiguous and uncertain situations, such as those dealing with the threat of widespread viral illness, may have pronounced psychological ramifications, there have been few studies that examined the factors that contributed to such outcomes. The purpose of the present investigation was to examine emotional reactions to a health threat. Design A structural equation model examined the interplay between anxiety and intolerance of uncertainty, as sequentially mediated by appraisals and coping strategies. Methods Adult participants over the age of 18 (N = 1,027) completed online self-report measures during the H1N1 pandemic in 2009. Results Greater intolerance of uncertainty was related to lower appraisals of self- and other control, which predicted low levels of problem-focused coping and greater reports of H1N1-related anxiety. Additionally, individuals with a high intolerance of uncertainty were more likely to perceive the pandemic as threatening and also were more apt to use emotion-focused coping strategies, and both of these factors predicted elevated levels of anxiety. Conclusions Together, these data indicate that threats, such as those related to a potential pandemic, not only have implications for physical health, but also for psychological distress, and that such outcomes vary with a constellation of appraisal and coping factors. Statement of contribution What is already known on this subject? It has been established that the public is often confused by the threat that a potential pandemic virus poses and that they are unsure of what information related to the disease they can trust. Government health agencies often walk the line of minimizing the threat to prevent panic, but simultaneously emphasize the importance of action (vaccination) to prevent a worldwide pandemic. What does this study add? Beyond the physical threat of a pandemic, a significant psychological toll may occur for certain individuals. Anxiety regarding H1N1 is heightened amongst those who cannot tolerate uncertainty. Appraisals of threat, control, and the use of emotion-focused coping mediate the above relationship.

Robust voice activity detection using higher-order statistics in the LPC residual domain

Abstract: This paper presents a robust algorithm for voice activity detection (VAD) based on newly established properties of the higher order statistics (HOS) of speech. Analytical expressions for the third and fourth-order cumulants of the LPC residual of short-term speech are derived assuming a sinusoidal model. The flat spectral feature of this residual results in distinct characteristics for these cumulants in terms of phase, periodicity and harmonic content and yields closed-form expressions for the skewness and kurtosis. Important properties about these cumulants and their similarity with the autocorrelation function are revealed from this exploratory part. They show that the HOS of speech are sufficiently distinct from those of Gaussian noise and can be used as a basis for speech detection. Their immunity to Gaussian noise makes them particularly useful in algorithms designed for low SNR environments. The proposed VAD algorithm combines HOS metrics with second-order measures, such as SNR and LPC prediction error, to classify speech and noise frames. The variance of the HOS estimators is quantified and used to yield a likelihood measure for noise frames. Moreover, a voicing condition for speech frames is derived based on the relation between the skewness and kurtosis of voiced speech. The performance of the algorithm is compared to the ITU-T G.729B VAD in various noise conditions, and quantified using the probability of correct and false classifications. The results show that the proposed algorithm has an overall better performance than G.729B, with noticeable improvement in Gaussian-like noises, such as street and parking garage, and moderate to low SNR.

Supersymmetry Parameter Analysis: SPA Convention and Project

Abstract: High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e+e- linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.

Search for direct third-generation squark pair production in final states with missing transverse momentum and two b-jets in √s = 8 TeV pp collisions with the ATLAS detector

Abstract: The results of a search for pair production of supersymmetric partners of the Standard Model third-generation quarks are reported. This search uses 20.1 fb-1 of pp collisions at sqrt{s}=8 TeV collected by the ATLAS experiment at the Large Hadron Collider. The lightest bottom and top squarks (b1 and t1 respectively) are searched for in a final state with large missing transverse momentum and two jets identified as originating from b-quarks. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the visible cross section for processes beyond the Standard Model. Exclusion limits at the 95% confidence level on the masses of the third-generation squarks are derived in phenomenological supersymmetric R-parity-conserving models in which either the bottom or the top squark is the lightest squark. The b1 is assumed to decay via b1->b chi0 and the t via t1->b chipm, with undetectable products of the subsequent decay of the chipm due to the small mass splitting between the chipm and the chi0.