POTABILIDADE DA ÁGUA DE CACIMBAS: ESTUDO DE CASO EM UM DISTRITO DA CIDADE DE BARRO, CEARÁ

Nesse sentido, o presente trabalho buscou analisar a qualidade físico-química e microbiológica da água proveniente de cacimbas na zona rural do distrito de Iara, cidade de Barro, Ceará. As amostras de água foram coletadas diretamente nas cacimbas em fracos esterilizados, depois foram armazenadas em caixas térmicas com gelo para conservação e transportadas para análises em laboratório. Foram realizadas análises físico-químicas para determinação da turbidez, condutividade elétrica, dureza total, cloretos, nitrogênio amoniacal, nitrato, nitrito, pH, alumínio, ferro total, sólidos totais dissolvidos e manganês, e análises microbiológicas para determinação de coliformes totais e Escherichia coli. Os resultados mostraram que a maioria das amostras de água proveniente das cacimbas apresentaram qualidade em relação aos parâmetros físico-químicos, mas algumas mostraram alterações em relação a dureza, e aos teores de nitrato e ferro. Todas as amostras apresentaram contaminação microbiológica por coliformes totais e somente uma não teve contaminação por E. coli. Os dados reforçam a questão da susceptibilidade das cacimbas a vários fatores de contaminação e a necessidade de maiores medidas para se rever hábitos da população que provocam a contaminação de cacimbas.

Assessment of the ozone tolerance of two soybean cultivars (Glycine max cv. Sambaíba and Tracajá) cultivated in Amazonian areas

Brazilian soybean cultivars (Glycine max Sambaíba and Tracajá) routinely grown in Amazonian areas were exposed to filtered air (FA) and filtered air enriched with ozone (40 and 80 ppb, 6 h/day for 5 days) to assess their level of tolerance to this pollutant by measuring changes in key biochemical, physiological, and morphological indicators of injury and in enzymatic and non-enzymatic antioxidants. Sambaíba plants were more sensitive to ozone than Tracajá plants, as revealed by comparing indicator injury responses and antioxidant stimulations. Sambaíba exhibited higher visible leaf injury, higher stomatal conductance, and a severe decrease in the carbon assimilation rate. Higher ozone level (80 ppb) caused an increase in cell death in both cultivars. Levels of malondialdehyde and hydrogen peroxide also increased in Tracajá exposed under 80 ppb. Sambaíba plants exhibited decreases in ascorbate and glutathione levels and in enzymatic activities associated with these antioxidants. The higher tolerance of the Tracajá soybean appeared to be indicated by reduced physiological injuries and lower stomatal conductance, which might decrease the influx of ozone and enhance oxidation-reduction reactions involving catalase, ascorbate peroxidase, ascorbate, and glutathione, most likely stimulated by higher hydrogen peroxide.

Dynamical model for competing opinions

We propose an opinion model based on agents located at the vertices of a regular lattice. Each agent has an independent opinion (among an arbitrary, but fixed, number of choices) and its own degree of conviction. The latter changes every time two agents which have different opinions interact with each other. The dynamics leads to size distributions of clusters (made up of agents which have the same opinion and are located at contiguous spatial positions) which follow a power law, as long as the range of the interaction between the agents is not too short; i.e., the system self-organizes into a critical state. Short range interactions lead to an exponential cutoff in the size distribution and to spatial correlations which cause agents which have the same opinion to be closely grouped. When the diversity of opinions is restricted to two, a nonconsensus dynamic is observed, with unequal population fractions, whereas consensus is reached if the agents are also allowed to interact with those located far from them. The individual agents' convictions, the preestablished interaction range, and the locality of the interaction between a pair of agents (their neighborhood has no effect on the interaction) are the main characteristics which distinguish our model from previous ones.

Experimental analysis of lateral impact on planar brittle material: spatial properties of cracks

The breakup of alkaline glass and alumina plates due to planar impacts on one of their lateral sides is studied. Particular attention is given to investigating the spatial location of the cracks within the plates. Analysis based on a phenomenological model suggests that bifurcations along the cracks' paths are more likely to take place closer to the impact region than far away from it, i.e., the bifurcation probability seems to lower as the perpendicular distance from the impacted lateral increases. It is also found that many observables are not sensitive to the plate material used in this work, as long as the fragment multiplicities corresponding to the fragmentation of the plates are similar. This gives support to the universal properties of the fragmentation process reported in previous experiments. However, even under the just mentioned circumstances, some spatial observables are capable of distinguishing the material of which the plates are made, which therefore suggests that this universality should be carefully investigated.

Polymorphism of the progesterone receptor gene associated with endometriosis in patients from Goiás, Brazil

We investigated a possible link between endometriosis and polymorphism of the progesterone receptor gene (PROGINS). The endometriosis group consisted of 54 patients with a diagnosis of endometriosis by laparoscopy, and the control group comprised 44 women without endometriosis. Genotypes for PROGINS polymorphisms (A1/A1, A1/A2 and A2/A2) were determined by polymerase chain reaction and analyzed on a 2% agarose gel stained with ethidium bromide. The frequency of polymorphic genotypes (A1/A2 and A2/A2) was significantly higher in patients with endometriosis (33%) than in the control group (16%). We conclude that there is a significant correlation between PROGINS polymorphism and endometriosis.

RsaI polymorphism of the ERβ gene in women with endometriosis

We examined the frequency of RsaI polymorphism of the ERβ gene in 54 patients diagnosed with endometriosis and 46 controls. Peripheral blood was collected from women undergoing laparoscopy with a confirmed diagnosis of endometriosis. Polymorphisms of the ERβ gene and p53 were assessed by PCR and analyzed on 2% agarose gel stained with ethidium bromide. The AG polymorphism genotype frequency in patients with endometriosis was 59.3%, with 40.7% GG. In the control group, the frequency of AG was 6.5%, with 93.5% GG. The frequency of heterozygous AG was nine times higher in patients with endometriosis than in the control group (P < 0.0001).

Experimental analysis of lateral impact on planar brittle material

The fragmentation of alumina and glass plates due to lateral impact is studied. A few hundred plates have been fragmented at different impact velocities and the produced fragments are analyzed. The method employed in this work allows one to investigate some geometrical properties of the fragments, besides the traditional size distribution usually studied in former experiments. We found that, although both materials exhibit qualitative similar fragment size distribution function, their geometrical properties appear to be quite different. A schematic model for two-dimensional fragmentation is also presented and its predictions are compared to our experimental results. The comparison suggests that the analysis of the fragments' geometrical properties constitutes a more stringent test of the theoretical models' assumptions than the size distribution.

Design and assembly of an experimental laboratory for the study of atmosphere-plant interactions in the system of fumigation chambers

An experimental laboratory was designed and assembled at the Botanical Institute of São Paulo, Brazil, in order to research atmosphere-plant interactions through the use of a system of fumigation chambers. A system of three "closed" fumigation chambers was designed to be used inside or outside the laboratory. The system was built to be used with a single pollutant or a mix of them. The innovation in this system is to allow chemical reactions inside the chambers that simulate atmospheric chemistry, especially photochemical processes involving high levels of ozone. Assessment of the performance and applicability of the system was based on the response of Nicotiana tabacum Bel W3 exposed to ozone produced alternatively by a generator and inside the chamber by reactions of its precursors. The results showed that the system can be well applied to the study of atmospheric chemistry interactions and the effects on plants.

Electrochemical potential of free and immobilized Cratylia mollis seed lectin

The electrochemical potentials for free or immobilized Cratylia mollis seed lectin (Cra) were obtained through potentiostatic techniques. A saline solution was used as support to control the charge distribution between saturated calomel electrode and platinum electrode (working electrode). The electrochemical potential to free Cra was determined at the following concentrations: 0.6, 0.9 and 1.0 mg/ml in an aerated environment under different temperatures (5, 10 and 20 degrees C). The best electrochemical potential was obtained with 1.0 mg/ml, at 5 and 10 degrees C, 87 and 102 mV, respectively. Electrochemical potential to Cra immobilized on glass beads activated with 3-aminopropyltriethoxysilane described a linear behavior in relation to the increase in glucose concentration. The development of techniques to define interface electrical parameters will be able to give information about charged groups adsorbed to electrode surface revealing interactions particularly in biological systems.

Measurements of atmospheric carboxylic acids and carbonyl compounds in São Paulo City, Brazil

Winter atmospheric measurements of gaseous lower carbonyl and carboxylic acids were carried out simultaneously (in 1999) at two distinct urban sites located in the city of São Paulo, Brazil. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. It has an unconventional mix of vehicle types in that a variety of gasoline blends, including oxygenated ones, are used. Mixing ratios of formic and acetic acids ranged, respectively, from 0.6 to 19.4 and from 0.1 to 10.6 ppbv in one of the sites studied and from 1.4 to 18.4 and from 0.4 to 6.7 ppbv in the other site. High values of formic to acetic ratios were found, especially in the latter site (average = 4.3), suggesting that photochemical production was the predominant source of the formic and acetic acid during the afternoon. Differing from the acids, levels of carbonyls were similar at both sites. Higher average mixing ratios of acetaldehyde and formaldehyde were found in the morning (18.9 and 17.2 ppbv) and gradually decreased from midday (9.5 and 11.8 ppbv) to evening (7.2 and 10.2 ppbv). In the morning, vehicular direct emission seemed to be the main primary source of formaldehyde and acetaldehyde, whereas at midday and evening these compounds appeared to be mainly formed by photochemistry. Secondary photochemical production of organic acids and aldehydes (rather than primary emissions from vehicles) was shown to be more important in São Paulo's atmosphere from midday to evening, particularly on days with strong solar radiation.