2,382 research outputs found
Confirmatory factor analysis of Clinical Outocmes in Routine Evaluation (CORE-OM) used as a measure of emotional distress in people with tinnitus
BACKGROUND:
People with troublesome tinnitus often experience emotional distress. Therefore a psychometrically sound instrument which can evaluate levels of distress and change over time is necessary to understand this experience. Clinical Outcomes in Routine Evaluation (CORE-OM) is a measure of emotional distress which has been widely used in mental health research. Although originally designed as a 4-factor questionnaire, factor analyses have not supported this structure and a number of alternative factor structures have been proposed in different samples. The aims of this study were to test the factor structure of the CORE-OM using a large representative tinnitus sample and to use it to investigate levels of emotional distress amongst people with a range of tinnitus experience.
METHODS:
The CORE-OM was completed by 342 people experiencing tinnitus who self-rated their tinnitus on a 5-point scale from ‘not a problem’ to ‘a very big problem’. Confirmatory factor analysis was used to test all ten factor models which have been previously derived across a range of population samples. Model fit was assessed using fit criterion and theoretical considerations. Mean scores on the full questionnaire and its subscales were compared between tinnitus problem categories using one-way ANOVA.
RESULTS:
The best fitting model included 33 of the 34 original items and was divided into three factors: negatively worded items, positively worded items and risk. The full questionnaire and each factor were found to have good internal consistency and factor loadings were high. There was a statistically significant difference in total CORE-OM scores across the five tinnitus problem categories. However there was no significant difference between those who rated their tinnitus ‘not a problem’, and ‘a small problem’ or ‘a moderate problem.’
CONCLUSION:
This study found a 3-factor structure for the CORE-OM to be a good fit for a tinnitus population. It also found evidence of a relationship between emotional distress as measured by CORE-OM and perception of tinnitus as a problem. Its use in tinnitus clinics is to be recommended, particularly when emotional distress is a target of therapy
Online Data Collection to Evaluate a Theoretical Cognitive Model of Tinnitus
Purpose The purpose of this article is to describe data collection considerations, methods, and response rates for a survey available both online and on paper. Methodological issues in the design of online data collection, and advantages and disadvantages of different data collection methods are discussed. Method A survey was compiled that included 9 full or partial clinical questionnaires designed to measure different components relevant to tinnitus distress. It was completed once by 342 members of the public with tinnitus. Respondents could choose whether to complete the survey online or on paper. Results Ninety-five percent of participants chose to complete the survey online. The advantages of an online self-administered questionnaire include low numbers of unanswered questions, convenience (particularly in a longer survey such as this), a fast return rate, and reduced expense. Age emerged as an important variable, with those opting to complete the paper-based version of the survey being older. Conclusions Online data collection has several advantages to both participants and researchers. However, cross-sectional studies such as that presented here should also offer paper questionnaires to avoid excluding certain subgroups of the population. Ethics and reporting guidelines for Internet-delivered questionnaire studies are available. These can usefully inform study design and guide high-quality reporting.Lucy Handscomb was funded by the British Tinnitus Asso-ciation. Deborah A. Hall and Derek J. Hoare were funded bythe Nat ional Institute for Health Research (NIHR) BiomedicalResearch Unit program
Twist Deformations of the Supersymmetric Quantum Mechanics
The N-extended Supersymmetric Quantum Mechanics is deformed via an abelian
twist which preserves the super-Hopf algebra structure of its Universal
Enveloping Superalgebra. Two constructions are possible. For even N one can
identify the 1D N-extended superalgebra with the fermionic Heisenberg algebra.
Alternatively, supersymmetry generators can be realized as operators belonging
to the Universal Enveloping Superalgebra of one bosonic and several fermionic
oscillators. The deformed system is described in terms of twisted operators
satisfying twist-deformed (anti)commutators. The main differences between an
abelian twist defined in terms of fermionic operators and an abelian twist
defined in terms of bosonic operators are discussed.Comment: 18 pages; two references adde
Hearts deficient in both Mfn1 and Mfn2 are protected against acute myocardial infarction
Mitochondria alter their shape by undergoing cycles of fusion and fission. Changes in mitochondrial morphology impact on the cellular response to stress, and their interactions with other organelles such as the sarcoplasmic reticulum (SR). Inhibiting mitochondrial fission can protect the heart against acute ischemia/reperfusion (I/R) injury. However, the role of the mitochondrial fusion proteins, Mfn1 and Mfn2, in the response of the adult heart to acute I/R injury is not clear, and is investigated in this study. To determine the effect of combined Mfn1/Mfn2 ablation on the susceptibility to acute myocardial I/R injury, cardiac-specific ablation of both Mfn1 and Mfn2 (DKO) was initiated in mice aged 4-6 weeks, leading to knockout of both these proteins in 8-10-week-old animals. This resulted in fragmented mitochondria (electron microscopy), decreased mitochondrial respiratory function (respirometry), and impaired myocardial contractile function (echocardiography). In DKO mice subjected to in vivo regional myocardial ischemia (30 min) followed by 24 h reperfusion, myocardial infarct size (IS, expressed as a % of the area-at-risk) was reduced by 46% compared with wild-type (WT) hearts. In addition, mitochondria from DKO animals had decreased MPTP opening susceptibility (assessed by Ca(2+)-induced mitochondrial swelling), compared with WT hearts. Mfn2 is a key mediator of mitochondrial/SR tethering, and accordingly, the loss of Mfn2 in DKO hearts reduced the number of interactions measured between these organelles (quantified by proximal ligation assay), attenuated mitochondrial calcium overload (Rhod2 confocal microscopy), and decreased reactive oxygen species production (DCF confocal microscopy) in response to acute I/R injury. No differences in isolated mitochondrial ROS emissions (Amplex Red) were detected in response to Ca(2+) and Antimycin A, further implicating disruption of mitochondria/SR tethering as the protective mechanism. In summary, despite apparent mitochondrial dysfunction, hearts deficient in both Mfn1 and Mfn2 are protected against acute myocardial infarction due to impaired mitochondria/SR tethering
Dark Matter, Muon g-2 and Other SUSY Constraints
Recent developments constraining the SUSY parameter space are reviewed within
the framework of SUGRA GUT models. The WMAP data is seen to reduce the error in
the density of cold dark matter by about a factor of four, implying that the
lightest stau is only 5 -10 GeV heavier than the lightest neutralino when m_0,
m_{1/2} < 1 TeV. The CMD-2 re-analysis of their data has reduced the
disagreement between the Standard Model prediction and the Brookhaven
measurement of the muon magnetic moment to 1.9 sigma, while using the tau decay
data plus CVC, the disagreement is 0.7 sigma. (However, the two sets of data
remain inconsistent at the 2.9 sigma level.) The recent Belle and BABAR
measurements of the B -> phi K CP violating parameters and branching ratios are
discussed. They are analyzed theoretically within the BBNS improved
factorization method. The CP parameters are in disagreement with the Standard
Model at the 2.7 sigma level, and the branching ratios are low by a factor of
two or more over most of the parameter space. It is shown that both anomalies
can naturally be accounted for by adding a non-universal cubic soft breaking
term at M_G mixing the second and third generations.Comment: 16 pages, 7 figures, plenary talk at Beyond The Desert '03, Castle
Ringberg, Germany, June 9, 2003. Typos correcte
Minkowski distances and standardisation for clustering and classification of high dimensional data
There are many distance-based methods for classification and clustering, and
for data with a high number of dimensions and a lower number of observations,
processing distances is computationally advantageous compared to the raw data
matrix. Euclidean distances are used as a default for continuous multivariate
data, but there are alternatives. Here the so-called Minkowski distances,
(city block)-, (Euclidean)-, -, -, and maximum distances are
combined with different schemes of standardisation of the variables before
aggregating them. Boxplot transformation is proposed, a new transformation
method for a single variable that standardises the majority of observations but
brings outliers closer to the main bulk of the data. Distances are compared in
simulations for clustering by partitioning around medoids, complete and average
linkage, and classification by nearest neighbours, of data with a low number of
observations but high dimensionality. The -distance and the boxplot
transformation show good results.Comment: Preliminary version; final version to be published by Springer, using
Springer's svmult LATEX styl
Yukawa unification in SO(10) with light sparticle spectrum
We investigate supersymmetric SO(10) GUT model with \mu<0. The requirements
of top-bottom-tau Yukawa unification, correct radiative electroweak symmetry
breaking and agreement with the present experimental data may be met when the
soft masses of scalars and gauginos are non-universal. We show how appropriate
non-universalities can easily be obtained in the SO(10) GUT broken to the
Standard Model. We discuss how values of BR(b-->s \gamma) and (g-2)_\mu
simultaneously in a good agreement with the experimental data can be achieved
in SO(10) model with \mu<0. In the region of the parameter space preferred by
our analysis there are two main mechanisms leading to the LSP relic abundance
consistent with the WMAP results. One is the co-annihilation with the stau and
the second is the resonant annihilation via exchange of the Z boson or the
light Higgs scalar. A very interesting feature of SO(10) models with negative
\mu is that they predict relatively light sparticle spectra. Even the heaviest
superpartners may easily have masses below 1.5 TeV in contrast to multi-TeV
particles typical for models with positive \mu.Comment: 23 pages, 5 figure
Polarization due to rotational distortion in the bright star Regulus
This is the full published article (retrieved from the 6 months post-publication posting on arXiv) including the Methods and Supplementary Information sections: 33 pages, 10 figures, 8 tablesPolarization in stars was first predicted by Chandrasekhar [1] who calculated a substantial linear polarization at the stellar limb for a pure electron-scattering atmosphere. This polarization will average to zero when integrated over a spherical star but could be detected if the symmetry is broken, for example by the eclipse of a binary companion. Nearly 50 years ago, Harrington and Collins [2] modeled another way of breaking the symmetry and producing net polarization - the distortion of a rapidly rotating hot star. Here we report the first detection of this effect. Observations of the linear polarization of Regulus, with two different high-precision polarimeters, range from +42 parts-per-million (ppm) at a wavelength of 741 nm to -22 ppm at 395 nm. The reversal from red to blue is a distinctive feature of rotation-induced polarization. Using a new set of models for the polarization of rapidly rotating stars we find that Regulus is rotating at 96.5(+0.6/-0.8)% of its critical angular velocity for breakup, and has an inclination greater than 76.5 degrees. The rotation axis of the star is at a position angle of 79.5+/-0.7 degrees. The conclusions are independent of, but in good agreement with, the results of previously published interferometric observations of Regulus [3]. The accurate measurement of rotation in early-type stars is important for understanding their stellar environments [4], and course of their evolution [5].Peer reviewedFinal Accepted Versio
Effects of ocean acidification on invertebrate settlement at volcanic CO<inf>2</inf> vents
We present the first study of the effects of ocean acidification on settlement of benthic invertebrates and microfauna. Artificial collectors were placed for 1 month along pH gradients at CO2 vents off Ischia (Tyrrhenian Sea, Italy). Seventy-nine taxa were identified from six main taxonomic groups (foraminiferans, nematodes, polychaetes, molluscs, crustaceans and chaetognaths). Calcareous foraminiferans, serpulid polychaetes, gastropods and bivalves showed highly significant reductions in recruitment to the collectors as pCO2 rose from normal (336-341 ppm, pH 8.09-8.15) to high levels (886-5,148 ppm) causing acidified conditions near the vents (pH 7.08-7.79). Only the syllid polychaete Syllis prolifera had higher abundances at the most acidified station, although a wide range of polychaetes and small crustaceans was able to settle and survive under these conditions. A few taxa (Amphiglena mediterranea, Leptochelia dubia, Caprella acanthifera) were particularly abundant at stations acidified by intermediate amounts of CO2 (pH 7. 41-7.99). These results show that increased levels of CO2 can profoundly affect the settlement of a wide range of benthic organisms. © 2010 Springer-Verlag
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