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Prevalence of mental disorders in the Zurich Cohort Study: a twenty year prospective study
- Jules Angst, Alex Gamma, Martin Neuenschwander, Vladeta Ajdacic-Gross, Dominique Eich, Wulf Rössler, Kathleen R. Merikangas
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- Journal:
- Epidemiologia e Psichiatria Sociale / Volume 14 / Issue 2 / June 2005
- Published online by Cambridge University Press:
- 11 October 2011, pp. 68-76
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- Article
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Background — In order to minimise retrospective recall in developing estimates of the prevalence of mental dis-orders in the general population, we conducted a prospective study of a cohort of youth from Zurich, Switzerland. Method — A 20 year prospective study of a community-based cohort aged 19-20 from Zurich Switzerland. The sample was enriched by subjects scoring high on the Symptom Checklist 90 R (Derogatis, 1977). A semi-structured diagnostic interview was administered by clinically experienced psychologists and psychiatrists. The six interviews from 1979 to 1999 assessed diagnoses and sub-threshold manifestations of major diagnostic categories (with the exception of schizophrenia) for the past twelve months, depending on the current DSM versions (DSM-IH, DSM-HI R, DSM-IV). Additional information on symptoms and treatment were collected for the years between the interviews. The reported prevalence rates are weighted for stratified sampling and cumulate the one-year rates of the six interviews. Results — The cumulative weighted prevalence rates for any psychiatric disorder were 48.6% excluding, and 57.7% including tobacco dependence. In addition 29.2% and 21.8%, respectively manifested sub-diagnostic syndromes. Overall there were no significant gender differences. The corresponding treatment prevalence rates were 22.4% and 31.1%, respectively for the diagnostic subjects and 6.9% and 6.1 %, respectively for the sub-diagnostic groups. The total treatment prevalence rate was 37.2% of the population (males 30.0%, females 44.1%). Conclusions — Our findings reveal that psychiatric disorders are quite common in the general population. When the spectra of mental disorders are considered, nearly three quarters of the general population will have manifested at least one of the mental disorders across their lifetime. Limitations — The data are based on a relatively small sample; a single age cohort, and the study was conducted in Zurich, Switzerland. These study features may diminish the generalisability of the findings.
Declaration of Interest: this work was supported by Grant 3200-050881.97/1 of the Swiss National Science Foundation, and Research Scientist Development Awards (MH 46376 and DA00293) from the US National Institutes of Health (Dr. Merikangas).
17 - Pistia stratiotes L. (Araceae)
- Edited by Rangaswamy Muniappan, Virginia Polytechnic Institute and State University, Gadi V. P. Reddy, University of Guam, Anantanarayanan Raman, Charles Sturt University, Orange, New South Wales
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- Book:
- Biological Control of Tropical Weeds Using Arthropods
- Published online:
- 04 August 2010
- Print publication:
- 05 March 2009, pp 332-352
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Summary
Taxonomy
Earliest descriptions of Pistia stratiotes L. (Araceae) were by the ancient Egyptians and by the Greek philosophers Dioscorides and Theophrastus. This plant has also been mentioned by Plinius (Stoddard, 1989). According to Bogner and Nicolson (1991) P. stratiotes is the solitary member of the subfamily Pistioidea in Araceae. However, USDA (2008) places it in the subfamily Aroideae along with the numerous other genera. The many synonyms and obsolete subspecific names (Plantatlas, 2006) attest to the variability of this taxonomically isolated species, which is the only free-floating aroid. The plant is known as water lettuce; other common names are available in Randall (2002).
Description
Pistia consists of a rosette of obovate to spatulate, velvety, light-green leaves (up to 40 cm long in African and American clones) (Fig. 17.1a, b), covered by short hairs, which trap air bubbles and thus enable buoyancy. The underside of leaves is densely hairy and almost white, with longitudinal ribs with embedded veins. The long feathery roots hang freely in the water. A clonal plant forms small colonies through stolons. Inflorescences are inconspicuous (7–12 × 5 mm) with short peduncles in the center of the rosette, growing on a stem. The spadix, enclosed in a whitish spathe, is pale green, hairy outside and glabrous inside. The spathe generally shows a constriction between the groups of male and the female flowers. The spathe below the constriction opens first in the morning hours to expose the wet stigma, whereas the male flowers remain enclosed.