472 research outputs found
Flutter and oscillating air-force calculations for an airfoil in a two-dimensional supersonic flow
An account is given of the Possio theory of non stationary flow for small disturbances in a two-dimensional supersonic flow and of its application to determination of the aerodynamic forces on an oscillating airfoil. Further application is made to the problem of wing flutter in the degrees of freedom - torsion, bending, and aileron torsion. Numerical tables for flutter calculations are provided for numerous values of the Mach number greater than unity. Results for bending-torsion wing flutter are discussed. The static instabilities of divergence and aileron reversal are examined as is a one degree of freedom case of torsional oscillatory instability
Theoretical study of air forces on an oscillating or steady thin wing in a supersonic main stream
Two-dimensional random walk in a bounded domain
In a recent Letter Ciftci and Cakmak [EPL 87, 60003 (2009)] showed that the
two dimensional random walk in a bounded domain, where walkers which cross the
boundary return to a base curve near origin with deterministic rules, can
produce regular patterns. Our numerical calculations suggest that the
cumulative probability distribution function of the returning walkers along the
base curve is a Devil's staircase, which can be explained from the mapping of
these walks to a non-linear stochastic map. The non-trivial probability
distribution function(PDF) is a universal feature of CCRW characterized by the
fractal dimension d=1.75(0) of the PDF bounding curve.Comment: 4 pages, 7 eps figures, revtex
Estradiol variability, stressful life events, and the emergence of depressive symptomatology during the menopausal transition
To examine the role of estradiol fluctuation in triggering depressive symptoms in the menopause transition and assess the role of recent very stressful life events (VSLEs) as a moderating factor in this relationship
Cardiovascular, hemodynamic, neuroendocrine, and inflammatory markers in women with and without vasomotor symptoms
Vasomotor symptoms (VMS) may be associated with an increased risk of cardiovascular disease. One candidate mechanism may involve alterations in physiological responses to stress. The current study therefore examined the relationship between self-reported VMS bother and cardiovascular, hemodynamic, neuroendocrine and inflammatory responses to an acute psychosocial stress protocol
Histories of abuse predict stronger within-person covariation of ovarian steroids and mood symptoms in women with menstrually related mood disorder
Individual differences in sensitivity to cyclical changes in ovarian steroids estradiol (E2) and progesterone (P4) have been implicated in the pathophysiology of menstrually related mood disorder (MRMD). However, no prospective studies have investigated psychosocial risk factors for sensitivity to hormone effects on mood in MRMD. Using a repeated measures approach and multilevel models, we tested the hypothesis that a history of abuse provides a context in which within-person elevations of E2 and P4 prospectively predict daily symptoms
Semiclassical Time Evolution and Trace Formula for Relativistic Spin-1/2 Particles
We investigate the Dirac equation in the semiclassical limit \hbar --> 0. A
semiclassical propagator and a trace formula are derived and are shown to be
determined by the classical orbits of a relativistic point particle. In
addition, two phase factors enter, one of which can be calculated from the
Thomas precession of a classical spin transported along the particle orbits.
For the second factor we provide an interpretation in terms of dynamical and
geometric phases.Comment: 8 pages, no figure
Toward the Reliable Diagnosis of DSM-5 Premenstrual Dysphoric Disorder: The Carolina Premenstrual Assessment Scoring System (C-PASS)
Despite evidence for the validity of premenstrual dysphoric disorder (PMDD) and its recent inclusion in DSM-5, variable diagnostic practices compromise the construct validity of the diagnosis and threaten the clarity of efforts to understand and treat its underlying pathophysiology. In an effort to hasten and streamline the translation of the new DSM-5 criteria for PMDD into terms compatible with existing research practices, we present the development and initial validation of the Carolina Premenstrual Assessment Scoring System (C-PASS). The C-PASS is a standardized scoring system for making DSM-5 PMDD diagnoses using 2 or more menstrual cycles of daily symptom ratings using the Daily Record of Severity of Problems (DRSP)
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