Convergence of the critical attractor of dissipative maps: Log-periodic oscillations, fractality and nonextensivity

For a family of logistic-like maps, we investigate the rate of convergence to the critical attractor when an ensemble of initial conditions is uniformly spread over the entire phase space. We found that the phase space volume occupied by the ensemble W(t) depicts a power-law decay with log-periodic oscillations reflecting the multifractal character of the critical attractor. We explore the parametric dependence of the power-law exponent and the amplitude of the log-periodic oscillations with the attractor's fractal dimension governed by the inflexion of the map near its extremal point. Further, we investigate the temporal evolution of W(t) for the circle map whose critical attractor is dense. In this case, we found W(t) to exhibit a rich pattern with a slow logarithmic decay of the lower bounds. These results are discussed in the context of nonextensive Tsallis entropies.Comment: 8 pages and 8 fig

Application of Comet assay to assess the effects of white bean meal on DNA of human lymphocytes

This study was conducted to evaluate the potential induction of genotoxic effects of white bean flour using the Comet assay. The test was conducted with human lymphocytes present in whole blood immediately after collection, by incubation with white bean flour in three concentrations (3.92, 9.52 and 18.18 mg/mL) at 37 ºC for 4 h followed by preparation of slides. Samples were considered positive (above 20% damage) when the damage observed to cellular DNA was higher than the negative control. No genotoxic potential was found at the doses tested. However, it would be premature to suggest absence of risk to human health of DNA damage since the exposure of cells to the extract was restricted to four hours rather than a whole cell cycle. Additionally, further information on toxicology should be obtained in future studies.Este estudo foi realizado para avaliar o potencial de indução de efeitos genotóxicos da farinha de feijão branco utilizando o teste do Cometa. O ensaio foi realizado com linfócitos humanos presentes no sangue imediatamente após a coleta, por incubação com farinha de feijão branco em três concentrações (3,92, 9,52 e 18,18 mg/mL) a 37 ºC por 4 h, seguida de preparação das lâminas. As amostras foram consideradas positivas (acima de 20% de dano), quando os danos observados no DNA celular foram maiores do que o controle negativo. Verificou-se que as doses testadas não mostraram potencial genotóxico. No entanto, seria prematuro fazer recomendações sobre o padrão de riscos para a saúde humana resultantes de danos ao DNA já que exposição das células ao extrato foi restrito ao período de quatro horas e não durante um ciclo celular completo. Além disso, outras informações sobre a toxicologia devem ser obtidas no futuro

Preliminary in vitro assessment of the potential toxicity and antioxidant activity of Ceiba speciosa (A. St.-Hill) Ravenna (Paineira)

ABSTRACT The bark tea of Ceiba speciosa, a tropical tree of the Malvaceae family, is used in the Northwestern Region of Rio Grande do Sul state, Brazil, to reduce blood cholesterol levels. However, there are no scientific data on the efficacy and safety of this plant. The aim of the present study was to evaluate the in vitro antioxidant and toxic potential of bark extracts of C. speciosa. We performed a preliminary phytochemical analysis by high-performance liquid chromatography-diode array detection (HPLC-DAD) and evaluated the oxidative damage to proteins and lipids, the radical scavenging effect, and genotoxicity of the lyophilized aqueous extract (LAECs) and the precipitate obtained from the raw ethanol extract (Cs1). The phytochemical profile demonstrated the presence of phenolic and flavonoid compounds. The LAECs and Cs1 prevented damage to lipids and proteins at concentrations of 50 and 10 µg/mL. They also showed a scavenging effect on 2,2-diphenyl-1-pricril-hydrazyl (DPPH) radicals in a concentration-dependent manner. Furthermore, no genotoxic effect was observed at concentrations of 10, 5 and 2 µg/mL in the Comet assay. The present study is the first evaluation regarding the characterization of C. speciosa and its safety, and the results demonstrate its antioxidant potential and suggest that its therapeutic use may be relatively safe

INVITED ARTICLE: YOUTH IN THE SRI LANKAN POPULATION: EXPANSION OF THEIR SIZE, ENGAGEMENT IN EDUCATION AND EMERGING CHALLENGES

The main objective of the paper is to investigate the population dynamics of present and future decades with special reference to the youth population, and emerging challenges of youth with special reference to their education. Apart from the population projection information, data was collected from various publications of the Ministry of Education and the Department of Census and Statistics. The youth (age 15-29 years) bulge will be at its peak during the period of 2030s and 2040s. The data indicates a significant increase of school dropouts in Sri Lanka – compared to 2018 by 2020 the student population declined by about 151,000. Although, during the period 2016 to 2018 there was an increase of students in the Collegiate cycle (Grade 12/13), during 2018 to 2020 the student population declined by 146,000 – ‘Lost Generation’. The COVID-19 impact on school education could be attributed to this drop and economic recession and escalation of inflation have further discouraged students to move into Grade 11 and above levels. In this present serious economic recession and inflation, those who left schools would be pushed into vulnerable employment categories, including the sex industry. Thus, appropriate policy reform is an immediate need, to capitalize on the full potential of the Sri Lankan youth for the development of the nation

Informacoes sobre os genotipos do bloco de cruzamentos de trigo do CNPT em 1990.

A Embrapa - Centro Nacional de Pesquisa de Trigo (CNPT), desenvolve germoplasma para as diversas regioes triticolas do pais, onde sistemas de cultivo, condicoes ambientais e outros fatores sao diferenciados. Para que esse objetivo seja alcancado, ha necessidade de uma grande variabilidade genetica, a qual e buscada pela observacao e avaliacao de trigos nacionais e estrangeiros.O objetivo deste trabalho e fornecer informacoes sobre os genotipos incluidos no Bloco de Cruzamentos, no ano de 1990, relativas a reacao as doencas (ferrugem do colmo, ferrugem da folha, oidio, giberela e virus do mosaico do trigo), a reacao ao aluminio do solo (crestamento) e as caracteristicas de planta (altura, ciclo, diametro do colmo, comprimento da espiga, numero de afilhos ferteis e numero de espiguetas ferteis), alem de dados sobre os cruzamentos. O Bloco de Cruzamento foi constituido de 264 genotipos, provenientes do Brasil e de outros 15 paises. O plantio foi realizado em duas epocas, no campo experimental do CNPT, e a reacao as racas de ferrugens e ao oidio foi avaliada em casa de vegetacao. Apresentaram-se com maior valor absoluto os seguintes genotipos: PF 85159 (para numero de afilhos), Tivoli e Triticale BR 4 (para diametro do colmo), IOF 54835 (para comprimento da espiga) e Triticale BR 4 (para numero de espiguetas ferteis). As cultivares PF 84491, PF 85202, PF 859238, PF 87167, PF 87373, PF 87509, PF 87915, PF 892 e Triticale BR 4 detacaram-se por apresentar resistencias as racas de ferrugens da folha e do colmo testadas e ao oidio.199