High Prevalence of Dementia in a Community-Based Survey of Older People from Brazil: Association with Intellectual Activity Rather than Education

Although several surveys have been conducted around the world, few surveys have investigated the prevalence of dementia in Latin America. The aim of this study was to estimate dementia prevalence in a community sample in Ribeirao Preto, Brazil, and to evaluate its distribution across several socio-demographic and clinical characteristics and habits. The population was aged 60 years and older and a representative sample from three different social regions. The screening instruments used in the first phase were the Mini-Mental State Examination, the Fuld Object-Memory Evaluation, the Informant Questionnaire on Cognitive Decline in the Elderly, and the Bayer Activities of Daily Living Scale. In the second phase, the Cambridge Examination was employed to diagnose dementia according to the DSM-IV criteria. The estimate of dementia prevalence was adjusted for screening instrument performance, using the positive and negative predictive values. The data were weighted to compare frequencies, considering the sampling and the non-response effect, and subjected to multivariate analysis. In all, 1.145 elderly subjects were evaluated (mean age: 70.9 years), of whom 63.4% were female and 52.8% had up to 4 years of schooling (participation rates at the first and the second phases were 62.6 and 60%, respectively). The observed and estimated prevalences of dementia were 5.9% and 12.5%, respectively (n = 68). Alzheimer's disease was the main cause (60.3%). Dementia was associated with old age, low education, stroke, absence of arthritis, and not reading books. The estimated prevalence of dementia was higher than the prevalence previously found. Associated factors confirmed the importance of intellectual activities in prevention.

Introducing education for sustainable development in the undergraduate laboratory: quantitative analysis of bioethanol fuel and its blends with gasoline by using solvatochromic dyes

The concept of Education for Sustainable Development, ESD, has been introduced in a period where chemistry education is undergoing a major change, both in emphasis and methods of teaching. Studying an everyday problem, with an important socio-economic impact in the laboratory is a part of this approach. Presently, the students in many countries go to school in vehicles that run, at least partially, on biofuels; it is high time to let them test these fuels. The use of renewable fuels is not new: since 1931 the gasoline sold in Brazil contains 20 to 25 vol-% of bioethanol; this composition is being continually monitored. With ESD in mind, we have employed a constructivist approach in an undergraduate course, where UV-vis spectroscopy has been employed for the determination of the composition of two fuel blends, namely, bioethanol/water, and bioethanol/gasoline. The activities started by giving a three-part quiz. The first and second ones introduced the students to historical and practical aspects of the theme (biofuels). In the third part, we asked them to develop a UV-vis experiment for the determination of the composition of fuel blends. They have tested two approaches: (i) use of a solvatochromic dye, followed by determination of fuel composition from plots of the empirical fuel polarity versus its composition; (ii) use of an ethanol-soluble dye, followed by determination of the blend composition from a Beer's law plot; the former proved to be much more convenient. Their evaluation of the experiment was highly positive, because of the relevance of the problem; the (constructivist) approach employed, and the bright colors that the solvatochromic dye acquire in these fuel blends. Thus ESD can be fruitfully employed in order to motivate the students; make the laboratory "fun", and teach them theory (solvation). The experiments reported here can also be given to undergraduate students whose major is not chemistry (engineering, pharmacy, biology, etc.). They are low-cost and safe to be introduced at high-school level.