Resumo A fração solúvel de petróleo (WSF) prejudica os organismos, porém os danos podem variar entre os níveis celular e tecidual. O objetivo do presente estudo foi avaliar o efeito agudo (24 h, 48 h e 72 h) e subcrônico (36 dias) da WSF (0%, 25% e 100%) em juvenis do peixe neotropical predador topo Hoplias aff. malabaricus. Os efeitos da WSF foram avaliados no nível molecular utilizando o ensaio do cometa e o teste do micronúcleo para o dano genômico e no nível morfológico através da identificação histológica de lesões patológicas no fígado. Em ambas exposições (aguda e subcrônica) encontramos baixos níveis de dano no DNA (< 10% de DNA na cauda do cometa) e frequência de micronúcleos não significativa em peixes expostos a WSF. As lesões mais significativas no fígado dos peixes expostos a WSF foram a vacuolização lipídica, hipertrofia e focos de necroses. Como estas lesões foram progressivas e persistentes, sua irreversibilidade pode afetar negativamente o recrutamento dos peixes, mesmo sendo um predador topo resistente.

Abstract Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage (< 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Abstract Since the first reported case of COVID-19 in Brazil, the public and private educational system started to close. Up to November 2020, scientific discussions about the return of schooling activities have been rarely performed by the national scientific community and police-makers. The great delay of school returning in Brazil contrasts with successful international strategies of school reopening worldwide and seems counterintuitive with the reopening of non-essential activities. Here, important issues to be considered before and during school reopening are reviewed and discussed. COVID-19 testing is essential to avoid disease spreading, but high cost of individual RT-qPCRs impairs an extensive testing strategy for school returning. To reduce costs and increase the speed of diagnosis, we tested the efficiency of a pooled-sample PCR strategy in a cohort of the educational staff in the city of Macaé/RJ, finding five asymptomatic individuals (0,66%) among the 754 people tested. Thus, a polled-sample PCR testing strategy of the educational staff might prevent infection spreading in schools at a reasonable cost. We discuss how our test strategy could be coupled with internationally recognized safety rules to allow for a safe school return and how countries from different world regions are dealing with educational activities during COVID-19 pandemic.

Abstract Campomanesia xanthocarpa (Mart.) O. Berg is a South American fruit tree species with important ecological and medicinal properties, which remnants are currently found mainly in isolated forest fragments. In this study, SSR markers from three different genomic origins (gene-linked, nuclear neutral, and organellar) were used to evaluate the patterns of genetic diversity, fine-scale spatial genetic structure and historical gene flow in fragmented forest formations of C. xanthocarpa from the Atlantic Forest in southern Brazil. Our results show that the forest fragments present moderate to high levels of genetic diversity in comparison to species presenting similar life traits, although a trend opposite to expected was observed concerning gene-linked and neutral SSR markers. The fine-scale spatial genetic structure revealed different patterns in short and large distance classes, with a distinct influence of gene-linked and neutral markers in driving the genetic structure in each distance class. The presence of an isolation-by-adaptation pattern implies the need for maintenance of the current remnants to assure the conservation of the private alleles. Finally, as the genetic diversity is found predominantly within forest fragments, programs of seed collection and/or genetic rescue should prioritize a larger number of individuals within each fragment, to increase the sampled diversity.

Resumo As características das cascas de árvores hospedeiras podem influenciar na distribuição e no desenvolvimento de epífitos. Amostras de casca foram suspensas em 10 e 20 mL de água destilada por 1, 4 e 24 h, para avaliação de métodos para a determinação do pH. Cascas de Myrcia brasiliensis, M. glabra e Myrsine coriacea hospedeiras de Cattleya intermedia foram coletadas no fuste e na copa, para avaliação do pH, da capacidade de retenção de água e da espessura. A altura da parte aérea e o número de raízes de C. intermedia crescidas no fuste e na copa das três espécies de árvore foram avaliados. O volume de solvente e o tempo de suspensão da casca influenciaram nos valores de pH. O pH e a espessura da casca de Myrsine coriacea foram maiores do que nas espécies de Myrcia. A altura da parte aérea e o número de raízes dos indivíduos de C. intermedia foram superiores na copa. Os parâmetros de crescimento das plantas não se relacionaram com o pH e a espessura da casca. Os dados trazem informações para subsequentes estudos sobre epífitos vasculares que incluam novos parâmetros e maiores amostragens, visando a subsidiar propostas de conservação de espécies ameaçadas.

Abstract The traits of the bark of host trees can influence the distribution and development of epiphytes. Bark samples were suspended in 10 and 20 mL of distilled water for 1, 4 and 24 h, to evaluate pH determination methods. Bark samples of Myrcia brasiliensis, M. glabra and Myrsine coriacea, three host trees of Cattleya intermedia had bark samples collected from the trunk and the crown, for the evaluation of the pH, water retention capacity and thickness. Shoot height (cm) and number of roots of C. intermedia grown on trunk and into the crown of the three species were evaluated. Volume of solvent and suspension time of the bark samples influenced pH values. The pH and thickness of Myrsine coriacea barks were higher when compared to Myrcia species. Shoot height and number of roots of C. intermedia individuals were significantly higher in the crown. The growth parameters of the reintroduced plants were unrelated to pH and bark thickness. The data bring information for the application of further vascular epiphyte studies including new parameters and greater samplings, in order to support proposals of the conservation of endangered species.

Abstract Formulations containing chitosan incorporated with methanolic fraction of Euphorbia umbellata (Pax) Bruyns, Euphorbiaceae, were studied aiming future applications of this new material as medicine. In order to investigate potential interactions between chitosan and the methanolic fraction (10, 50 and 100% in relation to the amount of chitosan) physicochemical characterization was performed by scanning electron microscopy, density, differential scanning calorimetry, thermogravimetry, X-ray diffraction, Fourier-transform infrared spectroscopy and colorimetry techniques. The phenolic compounds released from the chitosan membranes were evaluated using the Folin-Ciocalteau quantification method; antioxidant and antimicrobial activity were also studied. Increasing amounts of the methanolic fraction added to polymeric matrix produced different numbers of pores on the surface of the membranes, changes in the calorimetric, spectroscopic and crystalline properties as well as color changes, when compared to the inert membrane. These changes can be attributed to chemical interactions that occurred between the structure of the chitosan and the phenolic compounds present in the studied fraction. The matrix samples incorporated with 50 and 100% of the methanolic fraction presented different release profiles of phenolic compounds from the membranes (controlled manner) and promoted antioxidant and antimicrobial activity.

Carotenoid analysis in citrus is still a challenge due to their complex carotenoid profile and matrix acidity, which can promote isomerization and epoxide-furanoid rearrangements of these compounds. A new method for carotenoid extraction from freeze-dried citrus was developed. Extraction was carried out by magnetic stirring using ethyl acetate and methanol as solvents and Na2CO3 to neutralize organic acids. Liquid-liquid partition was achieved by centrifugation. Carotenoid quantification was accomplished by both UV-Vis and high-performance liquid chromatography-diode array detection (HPLC-DAD). Method repeatability (2.9 to 8.5%) and recovery (82 to 88%) were similar to reported values for procedures including all the carotenoid analysis steps. In 'Valencia' orange pulp, xanthophylls accounted for 98% of the total carotenoid content and the predominant carotenoids were (9Z)-violaxanthin, (all-E)-lutein and (9Z)-antheraxanthin. This method was further applied for carotenoid analysis in freeze-dried 'Tommy Atkins' mango pulp. The developed method is precise, accurate, fast and able to maintain epoxy-carotenoids stability during analysis.

RESUMO Introdução Substâncias psicoestimulantes são aquelas com capacidade de aumentar o estado de alerta e a motivação, além de possuírem propriedades antidepressivas, de melhora no humor e no desempenho cognitivo. Por esse motivo, muitos estudantes fazem consumo indiscriminado dessas substâncias. O objetivo deste estudo foi investigar o uso de substâncias estimulantes do sistema nervoso central pelos estudantes de graduação em Medicina da Universidade Federal do Rio Grande – Furg (RS), verificando as substâncias mais utilizadas, os motivos de uso e o perfil dos usuários. Métodos Foi realizado um estudo quantitativo observacional do tipo transversal com 200 estudantes de graduação em Medicina da Furg, matriculados nessa instituição no segundo semestre de 2015. Para a coleta de dados, utilizou-se um questionário padronizado e de autopreenchimento, com questões demográficas, comportamentais e sobre o uso de estimulantes. Foram coletadas informações acerca do consumo de cafeína, metilfenidato (Ritalina®), modafinil, piracetam, bebidas energéticas, anfetaminas e MDMA (ecstasy). Os dados foram analisados pelo teste exato de Fisher no pacote estatístico Stata 11.2. Resultados A prevalência de uso de substâncias estimulantes na vida foi de 57,5% (IC95% 50,9 a 64,4), sendo que 51,3% destes começaram a usá-las durante a faculdade. O uso de psicoestimulantes no momento da pesquisa teve prevalência de 52,3% (IC95% 45,3 a 59,3), valendo destacar que 16,6% dos estudantes consumiam mais de uma substância psicoestimulante. As substâncias mais consumidas foram bebidas energéticas (38,0%) e cafeína mais de cinco vezes por semana (27,0%). O consumo de estimulantes foi maior entre os estudantes das séries iniciais do curso. Os principais motivos alegados para o consumo de estimulantes foram compensar a privação de sono (47,4%) e melhorar raciocínio, atenção e/ou memória (31,6%). Em relação aos efeitos percebidos com o uso de estimulantes, 81,2% relataram redução do sono, 70,8% perceberam melhora na concentração, 58,0%, 56,1% e 54,0% reportaram, respectivamente, redução da fadiga, melhora no raciocínio e melhora do bem-estar. Conclusões O consumo de estimulantes entre os estudantes de Medicina foi elevado. Mais da metade dos estudantes relataram consumir psicoestimulantes, e um em cada três destes usou para melhorar o desempenho cognitivo. O uso dessas substâncias foi considerado eficaz pela maioria dos usuários, o que pode dificultar o combate a esse consumo.

ABSTRACT Introduction Psychostimulants are substances with the capacity to heighten alertness and motivation, also featuring antidepressant proprieties improving mood and cognitive performance. For this reason, many students use these substances indiscriminately. The purpose of the study was to investigate the use of substances stimulating the central nervous system by medical students at the Universidade Federal do Rio Grande (Furg), Brazil, verifying the most commonly used substances, the reason for use, and the user’s profile. Methods A quantitative, observational and cross-sectional study was conducted on 200 of Furg’s medical students enrolled at the institution in the second semester of 2015. Data collection was conducted by means of a standardized and auto-fill questionnaire, featuring questions on demographics, behavior and stimulant use. Information about the consumption of caffeine, methylphenidate, modafinil, piracetam, energy drinks, amphetamines, and MDMA was collected, with the results analyzed by means of the Fisher’s exact test on statistics program Stata 11.2. Results The prevalence of stimulant substance usage at some point in the students’ lives was 57.5% (95% CI 50.9 to 64.4), with 51.3% having started during college. Usage of psycho stimulants at the time of the research was 52.3% (95% CI 45.3 to 59.3), with 16.6% of the students consuming more than one psycho stimulant substance. The most popular substances were energy drinks (38%) and caffeine, consumed more than five times a week (27%). The consumption of stimulants was higher among students in the earlier stages of the degree. The main reasons given by the students were to compensate for sleep deprivation (47.7%) and to improve reasoning, attention, and/or memory (31.6%). Perceived effects of the stimulant use saw 81.2% reporting sleep reduction, 70.8% concentration improvement, 58.0% fatigue reduction, 56.1% improved reasoning abilities, and 54.0% heightened wellbeing. Conclusions Stimulant consumption among medical students was high. More than half of the students reported consuming psycho stimulants and one in three of them used them to improve cognitive performance. The use of these substances was considered effective by most of the users, which may hamper the fight against these substances.

ABSTRACT This study proposes eight stages according to the main discernible changes recorded throughout the embryonic development of Jenynsia multidentata. The development of morphological embryo structures, pigmentation, and changes in tissues connecting mother and embryo were included in the stage characterization. From the fertilized egg (Stage 1), an embryo reaches the intermediary stages when presenting yolk syncytial layer (Stage 2), initial pigmentation of the outer layers of the retina and dorsal region of the head (Stage 3), and the sprouting of the caudal (Stage 4), dorsal and anal fins (Stage 5). During the later stages, the ovarian folds enter the gills, and the body pigmentation becomes more intense (Stage 6), the body becomes elongated (Stage 7), and there is a greater intensity in body pigmentation and increased muscle mass (Stage 8). The dry weight of the batches varied between 0.6 ± 0.3 mg (Stage 3) to 54.6 ± 19.7 mg (Stage 8), but the dry weight of the maternal-embryonic connecting tissues remained almost constant. After controlling the effect of those reproductive tissues, the gain in dry weight of the batches throughout development increased exponentially from Stage 6, reflecting the increase in size and weight of the embryos due to matrotrophy.

RESUMEN Este estudio propone una clasificación constituida por ocho etapas, establecidas con base en los principales cambios macroscópicos registrados a lo largo del desarrollo embrionario de Jenynsia multidentata. El desarrollo de estructuras embrionarias, los patrones de pigmentación y los cambios en los tejidos de conexión entre la madre y el embrión fueron incluidos en la caracterización de cada etapa. Inicia con el huevo fertilizado (Etapa 1), siguiendo con etapas intermedias del embrión en las cuales es visible la capa sincitial del vitelo (Etapa 2), la pigmentación inicial de las capas externas de la retina y el dorso de la cabeza (Etapa 3), y la aparición de las aletas caudal (Etapa 4), dorsal y anal (Etapa 5). En las etapas posteriores, los pliegues del tejido ovárico se introducen por las branquias y se intensifica la pigmentación corporal (Etapa 6), el cuerpo se extiende (Etapa 7) y hay un marcado aumento en la pigmentación corporal y masa muscular (Etapa 8). El peso seco de los lotes varió entre 0,6 ± 0,3 mg (Etapa 3) y 54,6 ± 19,7 mg (Etapa 8); sin embargo, el peso seco del tejido que conecta a la madre con el embrión se mantuvo prácticamente constante. Después de controlar el efecto del peso seco de estos tejidos, la ganancia de peso seco de los lotes de embriones a lo largo del desarrollo aumentó de forma exponencial a partir de la Etapa 6, evidenciándose en el aumento en tamaño y peso de los embriones debido a la matrotrofia.

Resumo A influência da fração solúvel de petróleo (FSP) no consumo de presas e crescimento de juvenis da traíra Hoplias aff. malabaricus foi investigada. Os juvenis foram submetidos aos tratamentos FSP e Controle durante 28 dias, e adultos de matogrosso Hyphessobrycon eques foram oferecidos diariamente como presa para cada predador. O total de presas consumidas variou de 16 a 86 indivíduos. Apesar do menor consumo inicial de presas sob exposição de FSP, não houve diferenças significativas nas taxas de consumo entre os dois tratamentos. A FSP teve um efeito negativo no crescimento em tamanho de juvenis de H. aff. malabaricus. Embora a ausência de efeito no consumo de presas sugira uma relativa resistência de H. aff. malabaricus à exposição à FSP, o menor crescimento em tamanho dos indivíduos expostos ao poluente reflete possivelmente custos metabólicos. As implicações dos principais resultados nos níveis do organismo e da cadeia alimentar são discutidos, incluindo aspectos comportamentais e o papel desempenhado por este predador em ecossistemas aquáticos rasos.

Abstract The influence of the water-soluble fraction of petroleum (WSF) on prey consumption and growth of juvenile trahira Hoplias aff. malabaricus was investigated. Juveniles were submitted to either WSF or Control treatment over 28 days, and jewel tetra Hyphessobrycon eques adults were offered daily as prey for each predator. Total prey consumption ranged from 16 to 86 individuals. Despite the initially lower prey consumption under WSF exposure, there were no significant differences in overall feeding rates between the two treatments. Water-soluble fraction of petroleum had a negative effect on the growth in length of H. aff. malabaricus juveniles. Although unaffected, prey consumption suggested a relative resistance in H. aff. malabaricus to WSF exposition and the lower growth of individuals exposed to WSF than the Control possibly reflects metabolic costs. The implications of the main findings for the individual and the food chain are discussed, including behavioral aspects and the role played by this predator in shallow aquatic systems.

Resumo O presente estudo avaliou os efeitos genotóxicos do ar atmosférico sobre Tradescantia pallida var. purpurea em áreas urbanas com diferentes intensidades de tráfego veicular e em fragmentos de mata ciliar na Bacia do Rio dos Sinos (Rio Grande do Sul, Brasil), considerando a influência de condições climáticas prevalecentes nesses ambientes. Bimensalmente, de maio de 2012 a março de 2013, ramos com botões florais foram expostos por 8 h em ambientes urbanos e de mata ciliar nos municípios de Caraá, Taquara e Campo Bom nos trechos superior, médio e inferior, respectivamente, da Bacia do Rio dos Sinos. Simultaneamente, foram realizados controles negativos e levantados dados climáticos. Frequências de micronúcleos (MCN) foram determinadas em tétrades jovens de células-mãe de grãos de pólen e expressas como MCN/100 tétrades. Frequências de MCN significativamente superiores foram observadas em botões expostos nos ambientes urbanos e de matas ciliares em Taquara (até 7,23 e 4,80, respectivamente) e Campo Bom (até 4,90 e 4,23, respectivamente) do que em botões expostos em Caraá (até 2,90 e 2,50, respectivamente), na maioria das amostragens, e em relação ao controle negativo (até 1,93) em todos os meses. Ao longo do período monitorado, ocorreram variações significativas nas frequências de MCN em todos os pontos amostrais, com exceção do ambiente urbano de Caraá. Para os ambientes urbanos, foi observada relação entre a frequência de MCN, tráfego veicular e temperatura média. Para os fragmentos de mata ciliar, não houve associação entre a frequência de MCN e fatores climáticos. Tradescantia pallida var. purpurea pode ser considerada uma ferramenta útil para apontar áreas com poluição atmosférica aumentada, desde que, sob condições climáticas severas, a exposição das plantas seja evitada, para minimizar o efeito destas sobre a formação de micronúcleos.

Abstract The present study evaluated the genotoxic effects of the atmospheric air on Tradescantia pallida var. purpurea in urban areas with different intensities of vehicular traffic and in riparian forest fragments in the Sinos River Basin (Rio Grande do Sul, Brazil), considering the influence of climatic conditions prevailing in these environments. Bimonthly, from May 2012 to March 2013, cuttings with flower buds were exposed for 8 h in urban and riparian forest environments in the municipalities of Caraá, Taquara and Campo Bom in the upper, middle and lower sections, respectively, of the Sinos River Basin. Simultaneously, negative controls were made and climatic data were recorded. Micronuclei (MCN) frequencies were determined in young tetrads of pollen mother cells and expressed as MCN/100 tetrads. Significantly higher MCN frequencies were observed in buds exposed in urban and riparian forest environments in Taquara (up to 7.23 and 4.80, respectively) and Campo Bom (up to 4.90 and 4.23, respectively) than in buds exposed in Caraá (up to 2.90 and 2.50, respectively), in the majority of samplings, and in relation to the negative control (up to 1.93) in all months. Over the course of the period monitored, there were significant variations in MCN frequencies at all sampling points, with the exception of the urban environment in Caraá. For the urban environments, relation between the MCN frequency, vehicular traffic and mean temperature was observed. For the riparian forest fragments, there was no association between MCN frequency and climatic factors. Tradescantia pallida var. purpurea can be considered a useful tool to point out areas with increased atmospheric pollution, since the exposure of plants under severe climatic conditions is avoided to minimize their negative influence on the formation of micronuclei.

A Ipomoea cairica (L.) Sweet é uma trepadeira herbácea nativa, amplamente utilizada na medicina popular brasileira e inexistem informações sobre a propagação vegetativa. Em vista disso, objetivou-se avaliar a presença de folhas nas estacas, o substrato e a dose de reguladores vegetais mais adequados para a propagação por estaquia. Foram conduzidos dois experimentos, no primeiro, foram avaliados dois tipos de estacas (com e sem folhas) e quatro substratos (areia, casca de arroz carbonizada, latossolo vermelho distrófico + matéria orgânica - 1:1, latossolo vermelho distrófico + matéria orgânica + areia - 1:1:2), enquanto no segundo foram testadas cinco concentrações diferentes de AIB (0, 250, 500, 750 e 1000 mg L-1). Após 20 dias, obteve-se 86,2% de estacas enraizadas no substrato areia e, no segundo experimento, observou-se que o AIB não influenciou a porcentagem de enraizamento (94% em média). Conclui-se que a presença de folhas melhora a qualidade do enraizamento, que os substratos indicados para a propagação são areia e casca de arroz carbonizada devido ao maior enraizamento, fácil disponibilidade e baixo custo, e que a utilização de AIB na concentração 250 mg L-1 é a mais adequada para propagação por estaquia de I. cairica.

Ipomoea cairica (L.) Sweet is an herbaceous climbing plant widely used in Brazilian folk medicine and there is no information regarding its vegetative propagation. In view of this, the aim of this study was to evaluate the presence of leaves on stem cuttings and the most adequate substrate and level of plant growth regulators for propagation by stem cuttings of this morning glory. Two experiments were conducted, in the first, two types of stem cuttings (with and without leaves) and four substrates (sand; carbonized rice hull; Haplortox + organic matter - 1:1; Haplortox + organic matter + sand - 1:1:2) were evaluated, and in the second experiment five different concentrations of IBA (0, 250, 500, 750 and 1000 mg L-1) were tested. After 20 days, we obtained 86.2% of cuttings rooted in sand substrate and in the second experiment IBA did not affect the rooting percentage (94% on average). We can conclude that the presence of leaves improved the quality of rooting, the substrates indicated for propagation are sand and carbonized rice hull due to greater rooting, easy availability and low cost, and the use of IBA at 250 mg L-1 is more appropriate to propagation by stem cuttings of I. cairica.

No meio rural, a água de consumo humano é frequentemente captada por meio de sistemas precários. O objetivo do trabalho foi o de monitorar parâmetros físicos, químicos e microbiológicos da qualidade de água subterrânea captada em fontes para uso doméstico, relacionando suas posições na paisagem e à presença de proteção física. Trinta e cinco fontes de água subterrânea, localizadas na pequena bacia hidrográfica-PBH do Arroio Lino, área rural do Município de Agudo - RS, foram amostradas e classificadas quanto à proteção física e à posição na paisagem. Monitoraram-se, de janeiro a agosto de 2002, os seguintes parâmetros da água: pH, cor, carbono orgânico solúvel total (COST), N-NO3, N-NH3 e fósforo total (PT), Escherichia coli e coliformes totais. Em geral, os parâmetros variaram com a época de coleta, ficando ora acima, ora abaixo dos Valores Máximos Permissíveis previstos pelo Ministério da Saúde do Brasil. A posição das fontes nas cotas mais altas da paisagem da PBH mostrou-se determinante unicamente para a cor e o PT. A proteção rudimentar mostrou-se eficaz para o PT nas fontes posicionadas em cotas altas, no entanto apresentou respostas discrepantes na parte baixa da paisagem, considerando-se os parâmetros COST e N-NO3. A fonte drenada coletiva, sistema recomendado pela assistência técnica oficial, mostrou-se a mais eficaz em evitar a contaminação por Escherichia coli, restringindo também coliformes totais, fósforo total e N-NO3 em relação à fonte individual. A posição das fontes na paisagem e a presença de proteção física rudimentar podem ser utilizadas como critério parcial ao uso de fontes para captação de água.

In rural areas, water for human consumption is often captured by insecure systems. The objective of this work was monitoring some parameters of the quality of groundwater taken from sources, pointing out their position in the landscape and the presence of physical protection. For this , 36 sources in the watershed of Arroio Lino, a rural area of Agudo, RS, Brazil, were sampled and classified according their physical protection and position in the landscape. A monitoring program, from January to August 2002, was carried out to analyze the following parameters: pH, color, total soluble organic carbon - TSOC, N-NO3, N-NH3 and total phosphorus, E. coli and total coliforms. The parameters values changed with the time of collection and were often above the Maximum Allowable values provided by the Brazilian Ministry of Health. A rudimentary protection was efficient to the PT of the sources located in high levels; however it has present discrepant results for the low part of the landscape, considering the parameters TSOC e N-NO3. The collective drained source, system recommended by the official technical assistance, was the most efficient to avoid contamination by Escherichia coli, restricting also the levels of total coliforms, total phosphorus and N-NO3 as compared to the individual sources. The sources position in the landscape and the presence of a rudimentary physical protection can be employed as a partial criterion to accept that a water source be used for collecting water.

OBJETIVO: Verificar a prevalência de sintomas de distúrbios respiratórios do sono em crianças de baixo nível socioeconômico no Sul do Brasil. MÉTODOS: Foi realizado um estudo transversal em Uruguaiana (RS), utilizando questionário específico sobre sintomas de distúrbios respiratórios do sono, respondido pelos pais, em uma amostra de escolares de 9 a 14 anos participantes do International Study of Asthma and Allergies in Childhood (ISAAC). RESULTADOS: Foram respondidos 998 questionários de um total de 1.011 escolares elegíveis. Relato de ronco habitual ocorreu em 27,6% das crianças, apnéia em 0,8%, respiração oral diurna em 15,5% e sonolência diurna excessiva em 7,8%. Crianças com sonolência diurna excessiva apresentaram maior risco de ronco habitual (OR = 2,7; IC95% 1,4-5,4), apnéia (OR = 9,9; IC95% 1,2-51), respiração oral (OR = 13,1; IC95% 6,2-27,4) e problemas de aprendizado (OR = 9,9; IC95% 1,9-51,0). Rinite, fumo materno e testes cutâneos alérgicos estiveram significativamente associados a ronco habitual e respiração oral diurna. CONCLUSÕES: A prevalência de sintomas de distúrbios respiratórios do sono é elevada em crianças de 9 a 14 anos na cidade de Uruguaiana. A prevalência de ronco habitual foi quase duas vezes maior que a descrita nessa faixa etária em outras populações. Crianças com sonolência diurna excessiva parecem ter quase 10 vezes mais risco de problemas de aprendizado.

OBJECTIVE: To identify the prevalence of symptoms of sleep-disordered breathing among children of low socioeconomic status in the South of Brazil. METHODS: This was a cross-sectional study, carried out in the city of Uruguaiana, RS, in which specific questionnaire about the symptoms of sleep-disordered breathing was completed by the parents of a sample of schoolchildren aged 9 to 14 years, enrolled on the International Study of Asthma and Allergies in Childhood (ISAAC). RESULTS: From the total of 1,011 eligible schoolchildren, 998 questionnaires were completed. The parents of 27.6% of the children reported habitual snoring, while 0.8% reported apnea, 15.5% described daytime mouth breathing and 7.8% complained of excessive daytime sleepiness. Children with excessive daytime sleepiness were at greater risk of habitual snoring (OR = 2.7; 95%CI 1.4-5.4), apnea (OR = 9.9; 95%CI 1.2-51), mouth breathing (OR = 13.1; 95%CI 6.2-27.4) and learning difficulties (OR = 9.9; 95%CI 1.9-51.0). Rhinitis, maternal smoking and positive allergy skin test results were significantly associated with habitual snoring and daytime mouth breathing. CONCLUSIONS: There is an elevated prevalence of symptoms of sleep-disordered breathing among children from 9 to 14 in the city of Uruguaiana. The prevalence of habitual snoring was almost twice that described in this age group in other populations. Children with excessive daytime sleepiness appear to have almost 10 times the risk of learning difficulties.

Em muitos riachos e rios o ictioplâncton é mais abundante à noite do que de dia. Entretanto, em alguns rios isto não acontece e as larvas são igualmente abundantes durante o dia. Essa informação é importante para avaliar a distribuição e a produção de larvas nos rios. O objetivo deste trabalho foi testar se ocorrem diferenças na deriva larval durante os dois períodos do dia no Rio Solimões/Amazonas e no Rio Negro. Testamos esta hipótese comparando as densidades diurna e noturna em larvas de characiformes, clupeiformes e siluriformes durante cinco anos no Rio Solimões/Amazonas e um ano no Rio Negro. Encontramos que as larvas de três espécies de Characiformes e as larvas de Siluriformes de fato não modulavam sua deriva sendo igualmente abundantes durante o dia e à noite. Ao contrário, as larvas de Pellona spp. eram mais abundantes durante o dia. No Rio Negro as larvas eram mais abundantes à noite. Este resultado tem impor-tantes implicações para o planejamento de amostragem de larvas no Rio Solimões/Amazonas, pois indica que coletas diurnas estimam adequadamente a deriva de larvas de algumas espécies de characiformes e siluriformes no Rio Solimões/Amazonas, mas não das larvas de clupeiformes e das larvas do Rio Negro.

Many streams and large rivers present higher ichthyoplankton densities at night. However, in some rivers this does not occur and larvae are equally abundant during the day. Larval drift diel variation is an important information for planning sampling programs for evaluating larval distribution and production. The aim of this study was to test whether the abundance of larval fish was different at either period. We tested it by comparing day and night densities of characiform, clupeiform and siluriform larvae during five years in the Amazon and one year in Rio Negro. We found that larvae of three species of characiform and larvae of siluriform were equally abundant during day and night in the Amazon. Conversely, the catch of Pellona spp. larvae was significantly higher during the day. In Rio Negro, however, larval abundance was higher during the night. These results imply that day samplings estimate adequately the abundance of these characiform and siluriform larvae in the Amazon, but not Pellona larvae. Evaluations of larved densities of Rio Negro will have to consider night sampling.

Com o objetivo de investigar o efeito do conhecimento e atitudes pessoais, hábitos de higiene oral e uso de fluoretos sobre a total ausência de cáries, realizou-se um estudo do tipo caso-controle entre estudantes universitários da região sul do Brasil. A análise bruta por regressão logística condicional não demonstrou efeito para as variáveis relacionadas ao uso de fluoretos e hábitos de higiene oral (p > 0,20). Já o uso de fio dental apareceu como um fator de risco: os que afirmaram não usá-lo apresentaram "odds ratio" (OR) bruto de 0,70, e de 0,73 quando ajustado para visitas regulares ao dentista. O efeito para as visitas regulares ao dentista foi de risco. Pessoas com história de cárie visitavam mais os profissionais. Aqueles com história de cárie apresentaram um "odds ratio" bruto de 1,55; após o ajuste para uso de fio dental o risco foi levemente superior (OR = 1,67). Hábitos de higiene oral não demonstraram efeito protetor esperado. O uso de fluoretos não esteve significativamente associado à ausência de cáries. Permanece intrigando o fato de que algumas pessoas não desenvolvam cáries, mesmo não relatando cuidados considerados ideais à saúde bucal.

The purpose of this article was to investigate the effect of personal awareness and attitudes, the dentist's role, oral hygiene habits, and fluoride use on total absence of caries in adults, using a case-control study matched for sex and age with undergraduate students from two private Brazilian universities. Crude analysis using conditional logistic regression failed to show any effect for the related variables regarding fluoride use and oral hygiene habits (p > 0.20). Use of dental floss was the only exception in this set. It appeared as a risk factor, since individuals who stated not flossing presented a crude odds ratio (OR) of 0.70, or 0.73 when adjusted for regular visits to the dentist. The effect for regular visits to the dentist was that of a risk. Those with a history of caries presented a crude odds ratio of 1.55; after adjusting for dental floss use, the risk was slightly higher (OR = 1.67). Oral hygiene habits, contrary to the formulated hypothesis, did not display the expected protective effect. Likewise, fluoride use was not significantly associated with absence of caries. Individuals with a history of caries were used to visiting more professionals, confirming the formulated hypothesis for this variable. Nevertheless, it is still intriguing that some people fail to develop caries, even when they report not practicing measures considered ideal for oral health.