Caracterização hidrogeoquímica de água subterrânea em área de influência de futuras instalações de usinas hidrelétricas: bacia hidrográfica do rio Taquari-Antas/RS, Brasil

The identification and characterization of the hydrochemistry of the groundwaters has been done for seven wells. The sampling occurred during three bimonthly campaigns. The results classified the waters as of the calcium bicarbonated type for the majority of the samples, except for one well, whose composition is of the sodium bicarbonated type. The major ions found and how they determine the quality parameters are consistent with the reactions of mineral dissolution of the majority of volcanic rocks and the reactions with intrusion of alkaline rock in only one well. Anomalous values of nitrate in some wells alert to the impact of especially polluting sources at the time the reservoirs of the hydroeletric plant were formed.

Em busca da conservação ambiental: a contribuição da percepção ambiental para a formação e atuação dos profissionais da Química

Planet transformations caused by human intervention in the last 200 years are largely due to chemical impact. Therefore, this study aimed to identify and analyze the environmental perception of undergraduate students and lecturers in the Chemistry course of the Federal University of Lavras, accounting for the topics "Environmental Definition" and "Relationship between Chemistry and Environment". Two thematic axes for discussion were proposed using theories of Social Representation and Environmental Complexity, with the aim of stimulating the conservationist reasoning and actions. Such axes were proposed to give support to the education of chemists at the undergraduate level.

Paradigmas e evidências da nutrição peri-operatória

Understanding perioperative pathophysiology and implementing care regimes, through a multimodal approach, to reduce the organic response to stress after surgery and the related postoperative ileus, are major challenges. Multimodal surgical strategies such as pre-operative intake of a carbohydrate drink, instead of the usually recommended 2- to 6-hour period of nothing-bymouth, together with patient's education of the postoperative care plan, plus efficacious analgesia and early postoperative nutrition, among others, have been described to significantly impact on the previous variables. Therefore, these strategies accelerate rehabilitation and, as a consequence, decrease complications and hospital length of stay and, its related costs.

Callus induction and plant regeneration by Brazilian triticale and wheat genotypes

In order to determine the in vitro behavior of Brazilian triticale, 16 triticale genotypes, and three wheat genotypes used as checks, were sown in June 1994. The explants used were immature embryos. In addition to the genotype tests, two culture media for callus induction were also evaluated, i.e., MS (Murashige and Skoog, Physiol. Plant. 15: 473-497, 1962) medium containing 2.0 mg 2,4D/l, and MS medium containing 4.0 mg 2,4D/l. The plant regeneration protocol used was the one employed at the Laboratório de Cultura de Tecidos, Departamento de Plantas de Lavoura, Universidade Federal do Rio Grande do Sul, for wheat. Differences in plant regeneration were observed both among triticale and wheat genotypes, with triticale usually showing better regeneration than wheat. No differences were observed between the callus induction media.

Implications of ischemic penumbra for the diagnosis of brain death

The data reviewed here suggest the possibility that a global reduction of blood supply to the whole brain or solely to the infratentorial structures down to the range of ischemic penumbra for several hours or a few days may lead to misdiagnosis of irreversible brain or brain stem damage in a subset of deeply comatose patients with cephalic areflexia. The following proposals are advanced: 1) the lack of any set of clinically detectable brain functions does not provide a safe diagnosis of brain or brain stem death; 2) apnea testing may induce irreversible brain damage and should be abandoned; 3) moderate hypothermia, antipyresis, prevention of arterial hypotension, and occasionally intra-arterial thrombolysis may contribute to good recovery of a possibly large subset of cases of brain injury currently regarded as irreversible; 4) confirmatory tests for brain death should not replace or delay the administration of potentially effective therapeutic measures; 5) in order to validate confirmatory tests, further research is needed to relate their results to specific levels of blood supply to the brain. The current criteria for the diagnosis of brain death should be revised.

Plasma metanephrines: a novel and cost-effective test for pheochromocytoma

Pheochromocytomas are rare chromaffin cell tumors that nevertheless must be excluded in large numbers of patients who develop sustained or episodic hypertension as well as in many others with suggestive symptoms or with a familial history of pheochromocytoma. Diagnosis of pheochromocytoma depends importantly on biochemical evidence of excess catecholamine production by a tumor. Imperfect sensitivity and specificity of commonly available biochemical tests and the low incidence of the tumor among the tested population mean that considerable time and effort can be expended in confirming or ruling out pheochromocytoma in patients where the tumor is suspected. Measurements of plasma free metanephrines provide a superior test compared to other available tests for diagnosis of pheochromocytoma. In particular, the high sensitivity of plasma free metanephrines means that a normal test result reliably excludes all but the smallest of pheochromocytomas so that no other tests are necessary. Measurements of plasma free metanephrines, when systematically combined with other diagnostic procedures outlined in this review, provide a more efficient, reliable and cost-effective approach for diagnosis of pheochromocytoma than offered by previously available approaches.

Comparison of voluntary ethanol intake by two pairs of rat lines used as genetic models of anxiety

The relationship between anxiety-related behaviors and voluntary ethanol intake was examined in two pairs of rat lines by the oral ethanol self-administration procedure. Floripa high (H) and low (L) rats selectively bred for contrasting anxiety responses in the open-field test, and two inbred strains, spontaneously hypertensive rats (SHR) and Lewis rats which are known to differ significantly when submitted to several behavioral tests of anxiety/emotionality, were used (9-10 animals/line/sex). No differences in the choice of ethanol solutions (2%, days 1-4, and 4%, days 5-8, respectively) in a 2-bottle paradigm were detected between Floripa H and L rats (1.94 ± 0.37 vs 1.61 ± 0.37 g/kg for ethanol intake on day 8 by the Floripa H and L rat lines, respectively). Contrary to expectations, the less anxious SHR rats consumed significantly more ethanol than Lewis rats (respective intake of 2.30 ± 0.45 and 0.72 ± 0.33 g/kg on day 8) which are known to be both addiction-prone and highly anxious. Regardless of strain, female rats consumed more ethanol than males (approximately 46%). The results showed no relationship between high anxiety and voluntary intake of ethanol for Floripa H and L rats. A negative association between these two variables, however, was found for SHR and Lewis rat strains. Data from the literature regarding the association between anxiety and alcohol intake in animal models are not conclusive, but the present results indicate that factors other than increased inborn anxiety probably lead to the individual differences in ethanol drinking behavior.

Effect of hormone replacement on exercise cardiopulmonary reserve and recovery performance in subclinical hypothyroidism

Subclinical hypothyroidism (SH) patients present cardiopulmonary, vascular and muscle dysfunction, but there is no consensus about the benefits of levothyroxine (L-T4) intervention on cardiopulmonary performance during exercise. The aim of the present study was to investigate the effects of L-T4 on cardiopulmonary exercise reserve and recovery in SH patients. Twenty-three SH women, 44 (40-50) years old, were submitted to two ergospirometry tests, with an interval of 6 months of normalization of thyroid-stimulating hormone (TSH) levels (L-T4 replacement group) or simple observation (TSH = 6.90 μIU/mL; L-T4 = 1.02 ng/dL). Patients with TSH >10 μIU/mL were excluded from the study to assure that they would receive treatment in this later stage of SH. Twenty 30- to 57-year-old women with no thyroid dysfunction (TSH = 1.38 μIU/mL; L-T4 = 1.18 ng/dL) were also evaluated. At baseline, lower values of gas exchange ratio reserve (0.24 vs 0.30; P < 0.05) were found for SH patients. The treated group presented greater variation than the untreated group for pulmonary ventilation reserve (20.45 to 21.60 L/min; median variation = 5.2 vs 25.09 to 22.45 L/min; median variation = -4.75, respectively) and for gas exchange ratio reserve (0.19 to 0.27; median variation = 0.06 vs 0.28 to 0.18; median variation = -0.08, respectively). There were no relevant differences in cardiopulmonary recovery for either group at baseline or after follow-up. In the sample studied, L-T4 replacement improved exercise cardiopulmonary reserve, but no modification was found in recovery performance after exercise during this period of analysis.

Effect of air-temperature and diet composition on the drying process of pellets for japanese abalone (Haliotis discus hannai) feeding

The aim of this research was to study the effect of air-temperature and diet composition on the mass transfer kinetics during the drying process of pellets used for Japanese Abalone (Haliotis discus hannai) feeding. In the experimental design, three temperatures were used for convective drying, as well as three different diet compositions (Diets A, B and C), in which the amount of fishmeal, spirulin, algae, fish oil and cornstarch varied. The water diffusion coefficient of the pellets was determined using the equation of Fick's second law, which resulted in values between 0.84-1.94×10-10 m²/s. The drying kinetics was modeled using Page, Modified Page, Root of time, Exponential, Logarithmic, Two-Terms, Modified Henderson-Pabis and Weibull models. In addition, two new models, referred to as 'Proposed' models 1 and 2, were used to simulate this process. According to the statistical tests applied, the models that best fitted the experimental data were Modified Henderson-Pabis, Weibull and Proposed model 2, respectively. Bifactorial analysis of variance ANOVA showed that Diet A (fishmeal 44%, spirulin 9%, fish oil 1% and cornstarch 36%) presented the highest diffusion coefficient values, which were favored by the temperature increase in the drying process.

Assessing environmental impacts using a comparative LCA of industrial and artisanal production processes: "Minas Cheese" case

This study uses the Life Cycle Assessment (LCA) methodology to evaluate and compare the environmental impacts caused by both the artisanal and the industrial manufacturing processes of "Minas cheese". This is a traditional cheese produced in the state of Minas Gerais (Brazil), and it is considered a "cultural patrimony" in the country. The high participation of artisanal producers in the market justifies this research, and this analysis can help the identification of opportunities to improve the environmental performance of several stages of the production system. The environmental impacts caused were also assessed and compared. The functional unit adopted was 1 kilogram (Kg) of cheese. The system boundaries considered were the production process, conservation of product (before sale), and transport to consumer market. The milk production process was considered similar in both cases, and therefore it was not included in the assessment. The data were collected through interviews with the producers, observation, and a literature review; they were ordered and processed using the SimaPro 7 LCA software. According to the impact categories analyzed, the artisanal production exerted lower environmental impacts. This can be justified mainly because the industrial process includes the pasteurization stage, which uses dry wood as an energy source and refrigeration.

Sulphuric acid scarification effects on Brachiaria brizantha, B. humidicola and Panicum maximum seed dormancy release

Most tropical forage grass species have dormant seeds, which reduce percentages in germination tests. The objective of this study was to evaluate H2SO4 scarification effects on seed dormancy releasing, through germination time (T50) and variability among germination test replicates, in 630, 94 and 82 seed samples of B. brizantha, B. humidicola and P. maximum, respectively, tested at the Central Seed Testing Laboratory, Campinas, Brazil, from 1991 to 1999. Germination tests used two 4 x 100 replicates of intact and scarified seeds (15-, 10-, 5-minute treatments, respectively). Mean germination time (T50) and variability among germination replicates were also analysed. Statistical analysis was performed by t-test paired samples for means. Scarification promoted general decreases in T50, while variability among germination test replicates was reduced in B. brizantha. Scarification increase germination in B. brizantha and P. maximum, but is deleterious in B. humidicola.

Respiratory activity for the differentiation of vigor on soybean seeds lots

Currently, the highest interest with respect to the assessment of seed physiological quality is to obtain reliable results in a relatively short period of time. This initiative allows for prompt decisions during different phases of seed production primarily after physiological maturity. This research was performed to verify the efficiency and rapidity of the method of Pettenkofer to determine the respiratory activity and to differentiate vigor levels of soybean seed lots. Three lots of soybean seeds cv. 8000 were used. Seed performance was determined by respiratory activity, compared to the following tests: standard germination, germination first count, electrical conductivity, seedling emergence, seedling shoot and root length and total dry mass. Results ranked seed lots according to defferences in physiological quality. Seed imbibition and conditioning period in Pettenkofer's equipment were enough to detect differences in vigor among seed lots, showing that the determination of the respiratory activity is a promising procedure to identify differences in vigor levels among soybean seed lots.