A phase transition in a system driven by coloured noise

For a system driven by coloured noise, we investigate the activation energy of escape, and the dynamics during the escape. We have performed analogue experiments to measure the change in activation energy as the power spectrum of the noise varies. An adiabatic approach based on path integral theory allows us to calculate analytically the critical value at which a phase transition in the activation energy occurs

Large fluctuations and irreversibility in nonequilibrium systems.

Large rare fluctuations in a nonequilibrium system are investigated theoretically and by analogue electronic experiment. It is emphasized that the optimal paths calculated via the eikonal approximation of the Fokker-Planck equation can be identified with the locus of the ridges of the prehistory probability distributions which can be calculated and measured experimentally for paths terminating at a given final point in configuration sspace. The pattern of optimal paths and its singularities, such as caustics, cusps and switching lines has been calculated and measured experimentally for a periodically driven overdamped oscillator, yielding results that are shown to be in good agreement with each other

Symmetry breaking of fluctuation dynamics by noise color.

Activated escape is investigated for systems that are driven by noise whose power spectrum peaks at a finite frequency. Analytic theory and analog and digital experiments show that the system dynamics during escape exhibit a symmetry-breaking transition as the width of the fluctuational spectral peak is varied. For double-well potentials, even a small asymmetry may result in a parametrically large difference of the activation energies for escape from different wells

The epidemiology of major depression in South Africa: Results from the South African Stress and Health study

Background. Mental disorders are a major contributor to the burden of disease in all regions of the world. There are limited data on the epidemiology of major depressive disorder in South Africa. Methods. A nationally representative household survey was conducted between 2002 and 2004 using the World Health Organization Composite International Diagnostic Interview (CIDI) to establish a diagnosis of depression. The dataset analysed included 4 351 adult South Africans of all racial groups. Results. The prevalence of major depression was 9.7% for lifetime and 4.9% for the 12 months prior to the interview. The prevalence of depression was significantly higher among females than among males. The prevalence was also higher among those with a low level of education. Over 90% of all respondents with depression reported global role impairment. Conclusion. In comparison with data from other countries, South Africa has lower rates of depression than the USA but higher rates than Nigeria. The findings are broadly consistent with previous findings in South Africa. These findings are the first step in documenting a level of need for care in a context of significant under-funding of mental health services and research in South Africa

Burden of disease studies in the WHO European Region—a mapping exercise

The World Health Organization (WHO) and the Institute for Health Metrics and Evaluation (IHME) have produced numerous global burden of disease (GBD) estimates since the 1990s, using disability-adjusted life-years (DALYs). Here we attempt to identify studies that have either independent DALY estimates or build on the work of WHO and IHME, for the WHO European Region, categorize them by scope of disease analysis and geographic coverage, and briefly compare their methodology (age weighting, discounting and disability weights). Methods: Google and Google Scholar were used with the search terms ‘DALY’, ‘national burden of disease’, Member State names and researcher’s names, covering all years. Studies were categorized as: ‘specific’ (fewer than five disease categories or just risk factors for a single country), ‘specific, multicountry’ (fewer than five disease categories or just risk factors for more than one country), ‘extensive’ (covering five or more but not all disease categories for one country), ‘full, sub country’ (covering all relevant disease categories for part of one country) and ‘full, country’ (covering all relevant disease categories for one country). Results: A total of 198 studies were identified: 143 ‘specific’, 26 ‘specific, multicountry’, 7 ‘extensive’, 10 ‘full, sub country’ and 12 ‘full, country’ [England (1), Estonia (2), France (1), Romania (1), Serbia (1), Spain (3), Sweden (2) and Turkey (1)]. About 5 (20%) of the 25 examinable ‘extensive’, ‘full, sub country’ and ‘full, country’ studies calculated DALYs using GBD 2010 methodology. Conclusions: Independent burden of diseases studies in Europe have been located, and categorized by scope of disease analysis and geographic coverage. Methodological choices varied between independent ‘full, country’ studies

Hyperviscosity Syndrome Complicating Rheumatoid Arthritis: Report of Two Additional Cases and Review of the Literature

A hyperviscosity syndrome developed in two patients with rheumatoid arthritis. Analytic ultracentrifugation of the sera from one patient demonstrated 22S complexes. Intermediate, 22S, and 31S complexes were found in the second case. Platelet aggregometry and electron microscopy surveys of the platelet reactivity in one patient demonstrated inhibition of platelet reactivity caused by the presence of the high molecular weight complexes. These abnormalities, as well as the clinical bleeding, whole blood, and plasma viscosity, became normal after treatment. In vivo leukocytic function was studied with the Rebuck skin window technique, and phagosomal inclusions were observed in both the polymorphonuclear neutrophils and macrophages

Nonconventional stochastic resonance.

It is argued, on the basis of linear response theory (LRT), that new types of stochastic resonance (SR) are to be anticipated in diverse systems, quite different from the one most commonly studied to date, which has a static double-well potential and is driven by a net force equal to the sum of periodic and stochastic terms. On this basis, three new nonconventional forms of SR are predicted, sought, found, and investigated both theoretically and by analogue electronic experiment: (a) in monostable systems; (b) in bistable systems with periodically modulated noise; and (c) in a system with coexisting periodic attractors. In each case, it is shown that LRT can provide a good quantitative description of the experimental results for sufficiently weak driving fields. It is concluded that SR is a much more general phenomenon than has hitherto been appreciated

Surgical treatment of uterine prolapse in women with bladder exstrophy: report of two cases with modified Prolift™ procedure

The incidence of pelvic organ prolapse is 18% in women with bladder exstrophy. A vaginal technique to correct the prolapse may be preferable in these women with multiple abdominal operations in their histories. We have performed a modified Prolift™ procedure for the repair of severe uterine prolapse in two young women. A review of the literature is presented

Lunar regolith and structure mechanics

The topics are presented in viewgraph form and include the following: modeling of regolith-structure interaction in extraterrestrial constructed facilities; densification of lunar soil simulant; and vibration assisted penetration of lunar soil simulant