Reliability, validity and factor structure of the GHQ-28 used among elderly Iranians

Background: The object of this study was to develop an Iranian version of the General Health Questionnaire-28 (GHQ-28) for use with elderly subjects. Methods: The GHQ-28 Farsi version was evaluated for face validity among 204 elderly subjects aged 59 years or older, chosen randomly from residents of Tehran. The Composite International Diagnostic Interview (CIDI) was used to establish a gold standard diagnosis of mental disorders. Results: The GHQ-28 was an internally consistent measure. Cronbach's α, split-half coefficients and test-retest reliability were 0.9, 0.89 and 0.58 respectively. Four factors were extracted using factor analysis: "depression," "psychosocial activity," "anxiety," and "somatic." Using receiver operating curve (ROC) analysis, the optimum cutoff score for the GHQ-28 in this group was 19/20 (sensitivity 0.83, specificity 0.76). Using a loading of 0.6 or greater, a short form of the instrument (GHQ-15) (α = 0.9) was derived and correlated well with the longer form of the scale (r = 0.97). Using ROC analysis, the optimum cutoff score was 10/11 (sensitivity 0.83, specificity 0.69). Conclusions: The short and long forms of the GHQ-28 are suitable screening instruments for elderly Iranian residents, particularly those living in urban areas. © 2006 International Psychogeriatric Association

Cosmological and Black Hole Spacetimes in Twisted Noncommutative Gravity

We derive noncommutative Einstein equations for abelian twists and their solutions in consistently symmetry reduced sectors, corresponding to twisted FRW cosmology and Schwarzschild black holes. While some of these solutions must be rejected as models for physical spacetimes because they contradict observations, we find also solutions that can be made compatible with low energy phenomenology, while exhibiting strong noncommutativity at very short distances and early times.Comment: LaTeX 12 pages, JHEP.st

Reliability, validity and factor structure of the GHQ-28 used among elderly Iranians

Background: The object of this study was to develop an Iranian version of the General Health Questionnaire-28 (GHQ-28) for use with elderly subjects. Methods: The GHQ-28 Farsi version was evaluated for face validity among 204 elderly subjects aged 59 years or older, chosen randomly from residents of Tehran. The Composite International Diagnostic Interview (CIDI) was used to establish a gold standard diagnosis of mental disorders. Results: The GHQ-28 was an internally consistent measure. Cronbach's α, split-half coefficients and test-retest reliability were 0.9, 0.89 and 0.58 respectively. Four factors were extracted using factor analysis: "depression," "psychosocial activity," "anxiety," and "somatic." Using receiver operating curve (ROC) analysis, the optimum cutoff score for the GHQ-28 in this group was 19/20 (sensitivity 0.83, specificity 0.76). Using a loading of 0.6 or greater, a short form of the instrument (GHQ-15) (α = 0.9) was derived and correlated well with the longer form of the scale (r = 0.97). Using ROC analysis, the optimum cutoff score was 10/11 (sensitivity 0.83, specificity 0.69). Conclusions: The short and long forms of the GHQ-28 are suitable screening instruments for elderly Iranian residents, particularly those living in urban areas. © 2006 International Psychogeriatric Association

Do Quarks Obey D-Brane Dynamics?

The potential between two D0-branes at rest is calculated to be a linear. Also the potential between two fast decaying D0-branes is found in agreement with phenomenological heavy-quark potentials.Comment: 7 pages, no figures, LaTe

Quantum mechanics on space with SU(2) fuzziness

Quantum mechanics of models is considered which are constructed in spaces with Lie algebra type commutation relations between spatial coordinates. The case is specialized to that of the group SU(2), for which the formulation of the problem via the Euler parameterization is also presented. SU(2)-invariant systems are discussed, and the corresponding eigenvalue problem for the Hamiltonian is reduced to an ordinary differential equation, as it is the case with such models on commutative spaces.Comment: 12 pages, no figs, LaTe

Direction-Dependent CMB Power Spectrum and Statistical Anisotropy from Noncommutative Geometry

Modern cosmology has now emerged as a testing ground for theories beyond the standard model of particle physics. In this paper, we consider quantum fluctuations of the inflaton scalar field on certain noncommutative spacetimes and look for noncommutative corrections in the cosmic microwave background (CMB) radiation. Inhomogeneities in the distribution of large scale structure and anisotropies in the CMB radiation can carry traces of noncommutativity of the early universe. We show that its power spectrum becomes direction-dependent when spacetime is noncommutative. (The effects due to noncommutativity can be observed experimentally in the distribution of large scale structure of matter as well.) Furthermore, we have shown that the probability distribution determining the temperature fluctuations is not Gaussian for our noncommutative spacetimes.Comment: 26 pages. v3: Minor correction

M(atrix) Theory: Matrix Quantum Mechanics as a Fundamental Theory

A self-contained review is given of the matrix model of M-theory. The introductory part of the review is intended to be accessible to the general reader. M-theory is an eleven-dimensional quantum theory of gravity which is believed to underlie all superstring theories. This is the only candidate at present for a theory of fundamental physics which reconciles gravity and quantum field theory in a potentially realistic fashion. Evidence for the existence of M-theory is still only circumstantial---no complete background-independent formulation of the theory yet exists. Matrix theory was first developed as a regularized theory of a supersymmetric quantum membrane. More recently, the theory appeared in a different guise as the discrete light-cone quantization of M-theory in flat space. These two approaches to matrix theory are described in detail and compared. It is shown that matrix theory is a well-defined quantum theory which reduces to a supersymmetric theory of gravity at low energies. Although the fundamental degrees of freedom of matrix theory are essentially pointlike, it is shown that higher-dimensional fluctuating objects (branes) arise through the nonabelian structure of the matrix degrees of freedom. The problem of formulating matrix theory in a general space-time background is discussed, and the connections between matrix theory and other related models are reviewed.Comment: 56 pages, 3 figures, LaTeX, revtex style; v2: references adde

Wilson loops in strongly coupled noncommutative gauge theories

We discuss Wilson loop averages in 4-dimensional non-commutative superYang-Mills theory using the dual supergravity description. We postulate that the Wilson loops are located at the mimimum length scale $R$ in the fifth radial coordinate. We find that they exhibit a crossover from Coulomb type of behaviour for large loops, for which non-commutativity is unimportant, to area law for small loops, for which non-commutativity effects are large. The string tension, which can be read off from the area law, is controlled by the non-commutativity scale. The crossover itself, however, appears to involve loops of size of order $R$ which is much larger than the non-commutativity scale. The existence of the area law in non-commutative super Yang-Mills theory which persists up to a large crossover length scale provides further evidence for connection to an underlying string theory.Comment: 18 pages, Revised version to appear in Phys. Rev.

Reliability, validilty and factor structure of the GDS-15 in Iranian elderly

Objectives: Depressive disorders are a public health problem even in developing countries. Access to valid and reliable screening instruments is needed for conducting community surveys. The main objective of this study is to provide the Iranian version of the Geriatric Depression Scale-15 (GDS). Methods: The GDS-15 Farsi version was developed by translation and back translation. Two hundred and four subjects aged 59 years or older, who were chosen randomly from residents of the Ekbatan district of Tehran, the capital city of Iran, completed the GDS-15. The Composite International Diagnostic Interview (CIDI) was used to establish a gold standard diagnosis of major depressive disorders. Results: The GDS was found to be an internally consistent measure. Alpha, split-half coefficients and test-retest reliability were 0.9, 0.89 and 0.58 respectively. Two factors were extracted by using factor analysis and the principle component analysis (varimax rotation): 'depression' and 'psychosocial activity'. The Depression factor (omitting items 2, 9, 10, 13), which could be considered as a short form of the scale (α = 0.92), has significant correlation with the main scale (r = 0.58). Using receiver operating curve (ROC) analysis, the optimum cutoff score for GDS-15 is 7/8, yielding a sensitivity of 0.9 and a specificity of 0.84. The optimum cutoff score for GDS-11 is 6, yielding a sensitivity of 0.9 and a specificity of 0.83. Conclusion: The long and short forms of the GDS have excellent properties as screening instruments for major depression in older dwellers in Iran, particularly in urban areas, as presented in our findings. Copyright © 2006 John Wiley & Sons, Ltd