RESUMO
It is presented an alternative biological method based on biomineralization mechanisms of Magnetotactic Bacteria (MTB) for the removal in groundwater, of soluble elements such as Fe+2and Mn+2. In first place, it was compared the effectiveness of MTB retention methods for obtention of concentrated volumes in microorganisms, then, it was carried out an inoculation process in groundwater samples and evaluate the removal rate of Fe+2 and Mn+2 in constant conditions of pH and temperature. It was identified electromagnetic method is more efficient in MTB retention, and that the inoculation processes of an enriched solution with MTB in groundwater samples allow to get average removal rates of 47.86% for Fe+2 and 15.26% for Mn+2. In addition, it was evaluated the removal rate of other metals due to magnetic properties of biominerals inside of MTB magnetosome. The highest removal in all cases occurred between the interval of 3 and 5â¯min of interaction and tended to stabilize in time.
Assuntos
Água Subterrânea , Magnetossomos , Bactérias Aeróbias , Ferro , ManganêsRESUMO
SETTING AND OBJECTIVE: The International Study of Asthma and Allergies in Childhood (ISAAC) reported asthma prevalence in Peru to be among the highest in the world. We assessed the prevalence and morbidity of self-reported asthma in an underserved, peri-urban area of Lima, Peru, with limited medical access. DESIGN: The study was conducted in the outskirts of Lima from March to May 2011. Five hundred children aged 6-18 years were selected through cluster sampling. Parents completed a modified version of the ISAAC questionnaire. Children underwent spirometry testing. Those with a forced expiratory volume in one second (FEV1% predicted) îº80% were tested for reversibility using salbutamol. RESULTS: Of the 500 children selected, 71% participated. The prevalence of asthma was 16.7%. Asthma symptoms were associated with self-reported asthma (P < 0.001); 52.5% of children with asthma had ever used an inhaler (P < 0.001), and 27.1% had never been to the doctor for respiratory problems (P < 0.001). CONCLUSION: We found a high prevalence of self-reported asthma and high morbidity related to asthma symptoms in the previous 12 months among the study cohort. Symptoms were poorly controlled due to limited availability of medication and access to medical services.
Assuntos
Asma/epidemiologia , Acessibilidade aos Serviços de Saúde , Estudantes/estatística & dados numéricos , Adolescente , Asma/diagnóstico , Criança , Estudos de Coortes , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Pais , Peru/epidemiologia , Prevalência , Autorrelato , Espirometria , Inquéritos e Questionários , População UrbanaRESUMO
Three limestone slabs (approx. 20 cm2 each) were extracted from the El Tajin archaeological zone in Veracruz, Mexico. X-ray diffraction analysis revealed three components: calcite (81.2%), quartz (17.9%) and feldspar (0.9%). Calcite content by x-ray diffraction analysis was slightly higher than that determined by chemical reaction between the limestone sample and nitric acid. The latter analysis, carried out in triplicate, yielded a calcite content of 77.1%. Mean water absorption, density and porosity of the limestone samples were also determined. Dissolution of limestone samples was investigated using an experimental rainfall simulation chamber, in which the stone samples were irrigated with artificial rain matching the pH and the ionic composition with 40 rainfall samples collected at El Tajin from August 18, 2002, to April 9, 2003. According to calcium and bicarbonate net concentrations found in the effluent of the chamber, a chemical mechanism by which limestone at El Tajin is dissolved by acid rain is proposed. A model used to investigate the air transport pathways corresponding to precipitation events at El Tajin shows that air parcels come mainly from the Gulf of Mexico, although no directional preference is evident for acidic vs. non-acidic events.
Assuntos
Chuva Ácida/efeitos adversos , Arqueologia , Carbonato de Cálcio , Poluentes Químicos da Água/efeitos adversos , Movimentos do Ar , Silicatos de Alumínio , Bicarbonatos/análise , Cálcio/análise , Humanos , Concentração de Íons de Hidrogênio , México , Compostos de Potássio , QuartzoRESUMO
The present paper deals with the urban-rural differences in food consumption patterns and nutrient intake of poor families in Guatemala, based on consumption data collected in 1987 using the 24-hour dietary recall method. The main results show mean intake energy and protein levels below the mean recommended allowances in both groups of families included in the study. Higher levels of protein and calorie intakes, however, are also reported for families in the urban areas. In spite of the fact that caloric and protein intake levels are lower in the urban sector, the food consumption pattern is more diversified and of better quality than the habitual diet of the rural families. This explains why a higher average level of calcium and vitamin A (retinol equivalents) is observed, in comparison with the rural families.
Assuntos
Dieta , Ingestão de Energia , Necessidades Nutricionais , Estudos de Coortes , Registros de Dieta , Comportamento Alimentar , Guatemala , Humanos , Estado Nutricional , Pobreza , Desnutrição Proteico-Calórica , Distribuição Aleatória , Estudos Retrospectivos , População Rural , População UrbanaRESUMO
The purpose of the present study was to evaluate the impact of changes in income and retail prices on the consumption of foods by low income groups living in Guatemala. A representative sample of 200 low-income families living in a marginal area of Guatemala City, known as "El Milagro", was studied. Of five surveys conducted, two concerned food demand exclusively. In the first one the food consumption survey used was the 24-hr recall method, and the second survey was related to income expenditures, obtaining weekly information on expenses on foods and in other items. The expenditures were utilized to estimate the elasticity of demand, including foods. Total family expenses were used as an estimation of total income. Analyses of the data were obtained by forming three income groups: families with per capita expenses below the per capita cost of the foods basket; families with per capita expenses within the cost of the food basket, and the cost of a modified food basket (all expenses); families with an income above the modified food basket. The analyzed data clearly confirmed that: a) food expenses increase less as a response to income increases than expenses for other family needs; the income elasticity for foods high in carbohydrates content is lower with respect to food of animal origin and the income elasticity of the demand for rice and wheat bread are higher in comparison to the more basic foods such as beans, maize and maize products, roots and tubers.
Assuntos
Dieta/economia , Alimentos/economia , Renda , Áreas de Pobreza , Criança , Pré-Escolar , Custos e Análise de Custo , Guatemala , Humanos , Necessidades Nutricionais , Análise de Regressão , Estudos de AmostragemRESUMO
The present study was conducted as part of an evaluation of the economic and nutritional effects of a crop diversification program for small-scale farmers in the Western highlands of Guatemala. Linear programming models are employed in order to obtain optimal combinations of traditional and non-traditional food crops under different ecological conditions that: a) provide minimum cost diets for auto-consumption, and b) maximize net income and market availability of dietary energy. Data used were generated by means of an agroeconomic survey conducted in 1983 among 726 farming households. Food prices were obtained from the Institute of Agrarian Marketing; data on production costs, from the National Bank of Agricultural Development in Guatemala. The gestation periods for each crop were obtained from three different sources, and then averaged. The results indicated that the optimal cropping pattern for the minimum-cost diets for auto consumption include traditional foods (corn, beans, broad bean, wheat, potato), non-traditional foods (carrots, broccoli, beets) and foods of animal origin (milk, eggs). A significant number of farmers included in the sample did not have sufficient land availability to produce all foods included in the minimum-cost diet. Cropping patterns which maximize net incomes include only non-traditional foods: onions, carrots, broccoli and beets for farmers in the low highland areas, and raddish, broccoli, cauliflower and carrots for farmers in the higher parts. Optimal cropping patterns which maximize market availability of dietary energy include traditional and non-traditional foods; for farmers in the lower areas: wheat, corn, beets, carrots and onions; for farmers in the higher areas: potato, wheat, raddish, carrots and cabbage.