RESUMO O objetivo deste estudo é melhorar o modelo de cadeias de Markov de dois estados usado em Hidrologia para geração sintética de fluxos diários. O modelo apresentado em (4) e estudado em (2) e (3) baseia-se em duas cadeias de Markov, ambas de ordem um, para a determinação do estado do fluxo. Em algumas áreas da Hidrologia, onde cadeias de Markov de ordem um são usadas com sucesso para modelar eventos como precipitação diária, pesquisadores têm se mostrado preocupados com a ordem ótima de tais cadeias (10). Neste artigo, uma resposta a uma preocupação similar sobre o modelo desenvolvido em (4) é dada, usando o critério de informação de Bayes para estabelecer a ordem de cadeia de Markov que melhor se encaixa nos dados. A metodologia é aplicada a uma série de fluxos diários de sete rios brasileiros. Observa-se que os dados gerados usando a ordem estimada de cada cadeia são mais próximos dos dados reais do que o modelo proposto em (4), com exceção de dois locais que têm as menores séries temporais e estão - localizados nas regiões mais secas.

ABSTRACT The aim of this study is to further investigate the two-state Markov chain model for synthetic generation of daily streamflows. The model presented in (4) to determine the state of the stream and later studied in (2) and (3) is based on two Markov chains, both of order one. In some areas of Hydrology, where Markov chains of order one have been successfully used to model events such as daily rainfall, researchers are concerned about the optimal order of the Markov chain (10). In this paper, an answer to a similar concern about the model developed in (4) is given using the Bayesian Information Criterion (BIC) to establish the order of the Markov chain which best fits the data. The methodology is applied to daily flow series from seven Brazilian sites. It is seen that the data generated using the optimal order are closer to the real data than when compared to the model proposed in (4) with the exception of two sites, which exhibit the shortest time series and are located in the driest regions.

Solos associados aos Complexos Rupestres de Altitude no Brasil destacam-se pela baixa fertilidade química, baixa saturação de bases e elevados teores de alumínio trocável. Esta condição estressante impõe pressões evolutivas que determinam o sucesso ecológico de espécies capazes de tolerar ou acumular grandes quantidades de alumínio. Vários métodos analíticos são utilizados para mapeamento de elementos químicos em estruturas biológicas, como microfluorescência de raios-X (μ-EDX) e testes histoquímicos. O objetivo do presente trabalho foi combinar a μ-EDX e testes histoquímicos para quantificar o teor de Al em espécies vegetais de Complexos Rupestres de Altitude, e identificar os principais sítios de bioacumulação de Al. Cinco das espécies investigadas apresentaram concentração total de Al maior que 1000 mg kg−1. As principais hiperacumuladoras de Al,Lavoisiera pectinata, Lycopodium clavatume Trembleya parviflora, apresentaram reação positiva nos testes histoquímicos com Chrome Azurol e Aluminon. Alta correlação positiva foi observada entre as concentrações totais de Al e as magnitudes de sinal obtidas por μ-EDX. A análise com o uso da μ-EDX mostrou-se uma ferramenta promissora para mapear e quantificar Al em espécies hiperacumuladoras, constituindo uma importante técnica não destrutiva. Testes histoquímicos podem ser úteis na identificação de padrões de acumulação de Al em amostras vegetais antes de serem submetidas a uma minuciosa análise com a μ-EDX.

The soils developed under High Altitude Rocky Complexes in Brazil are generally of very low chemical fertility, with low base saturation and high exchangeable aluminium concentration. This stressful condition imposes evolutionary pressures that lead to ecological success of plant species that are able to tolerate or accumulate high amounts of aluminium. Several analytical methods are currently available for elemental mapping of biological structures, such as micro-X-ray fluorescence (μ-EDX) and histochemical tests. The aim of this study was to combine μ-EDX analysis and histochemical tests to quantify aluminium in plants from High Altitude Rocky Complexes, identifying the main sites for Al-accumulation. Among the studied species, five showed total Al concentration higher than 1000 mg kg−1. The main Al-hyperaccumulator plants,Lavoisiera pectinata, Lycopodium clavatumand Trembleya parviflora presented positive reactions in the histochemical tests using Chrome Azurol and Aluminon. Strong positive correlations were observed between the total Al concentrations and data obtained by μ-EDX analysis. The μ-EDX analysis is a potential tool to map and quantify Al in hyperaccumulator species, and a valuable technique due to its non-destructive capacity. Histochemical tests can be helpful to indicate the accumulation pattern of samples before they are submitted for further μ-EDX scrutiny.

Our aim was to determine the frequencies of the angiotensin-converting enzyme (ACE) gene alleles D and I and any associations to cardiovascular risk factors in a population sample from Rio de Janeiro, Brazil. Eighty-four adults were selected consecutively during a 6-month period from a cohort subgroup of a previous large cross-sectional survey in Rio de Janeiro. Anthropometric data and blood pressure measurements, echocardiogram, albuminuria, glycemia, lipid profile, and ACE genotype and serum enzyme activity were determined. The frequency of the ACE*D and I alleles in the population under study, determined by PCR, was 0.59 and 0.41, respectively, and the frequencies of the DD, DI, and II genotypes were 0.33, 0.51, and 0.16, respectively. No association between hypertension and genotype was detected using the Kruskal-Wallis method. Mean plasma ACE activity (U/mL) in the DD (N = 28), DI (N = 45) and II (N = 13) groups was 43 (in males) and 52 (in females), 37 and 39, and 22 and 27, respectively; mean microalbuminuria (mg/dL) was 1.41 and 1.6, 0.85 and 0.9, and 0.6 and 0.63, respectively; mean HDL cholesterol (mg/dL) was 40 and 43, 37 and 45, and 41 and 49, respectively, and mean glucose (mg/dL) was 93 and 108, 107 and 98, and 85 and 124, respectively. A high level of ACE activity and albuminuria, and a low level of HDL cholesterol and glucose, were found to be associated with the DD genotype. Finally, the II genotype was found to be associated with variables related to glucose intolerance.

The effectiveness of an aqueous extract of Caryocar brasiliense (Caryocaraceae) Camb pulp, popularly known in Brazil as pequi, against clastogenicity induced by cyclophosphamide and bleomycin was evaluated using an in vivo mouse bone marrow cell micronuclei test, an in vitro Chinese hamster ovary cell (CHO-K1) chromosome aberration test and an in vitro antioxidant assay based on the oxidative damage to 2-deoxy-D-ribose (2-DR) induced by hydroxyl radicals (•OH) generated by the reaction between ascorbic acid and (Fe III)-EDTA. In mouse bone marrow cells the extract showed a protective effect against micronuclei induced by cyclophosphamide and bleomycin but did not interfere with polychromatic bone marrow erythrocyte proliferation, except when the mice had been treated with the highest dose of cyclophosphamide. When CHO-K1 cells were pretreated by adding 0.01, 0.05 or 0.1 mL of extract per mL of cell culture medium 24 or 48 h before bleomycin or cyclophosphamide there was a protective effect against chromosome breaks and a significant decrease in the mitotic index (a measure of cytotoxicity) of the CHO-K1 cells. The extract also had a protective effect against oxidative hydroxyl radical damage to 2-DR. This study suggests that C. brasiliense pulp aqueous extract has anticlastogenic potential, possibly due to its antioxidative properties.

The objective of this work was to identify QTLs for liveweight in a candidate region of bovine chromosome 5. Half-sib families from two lines, one traditional and the other new, of Canchim beef cattle (5/8 Charolais + 3/8 Zebu) were genotyped for four microsatellite markers, including the microsatellite in the IGF-1 (insulin-like growth factor-1) promoter region. Significant differences in allele distribution between the two lines were found for three markers. Interval mapping analyses in this region indicated the presence of a QTL controlling birth weight (p < 0.05) and of a QTL influencing breeding value for yearling weight (p < 0.01) in the newer line of the breed. The previously identified interaction between the IGF-1 genotype and genetic group strengthens the hypothesis of a linked QTL rather than an IGF-1 effect on growth traits in the Canchim cattle.