133 research outputs found

    Arithmetic fuchsian groups and space time block codes

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    In the context of space time block codes (STBCs) the theory of arithmetic Fuchsian groups is presented. Additionally, in this work we present a new class of STBCs based on arithmetic Fuchsian groups. This new class of codes satisfies the property full-diversity, linear dispersion and full-rate. Mathematical subject classification: 18B35, 94A15, 20H10

    Arithmetic fuchsian groups and space time block codes

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    In the context of space time block codes (STBCs) the theory of arithmetic Fuchsian groups is presented. Additionally, in this work we present a new class of STBCs based on arithmetic Fuchsian groups. This new class of codes satisfies the property full-diversity, linear dispersion and full-rate. Mathematical subject classification: 18B35, 94A15, 20H10.48549

    Very Low Temperature Tunnelling Spectroscopy in the heavy fermion superconductor PrOs4_4Sb12_{12}

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    We present scanning tunnelling spectroscopy measurements on the heavy fermion superconductor PrOs4_4Sb12_{12}. Our results show that the superconducting gap opens over a large part of the Fermi surface. The deviations from isotropic BCS s-wave behavior are discussed in terms of a finite distribution of values of the superconducting gap.Comment: 4 pages, 4 figure

    Overcoming seed dormancy in visgueiro-of-the-igapĂł (Parkia discolor)

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    This study aimed to evaluate the effects of pregerminative mechanical scarification treatments, as well as heat pre-treatments on the germination of visgueiro-of-the-igapĂł (Parkia discolor Spruce ex Benth.) seeds. The first experiment, with a completely randomized design and four repetitions, evaluated these pre-treatments: control (without pre-treatment); clipping at the distal portion; clipping at the proximal portion (hilum); clipping at the proximal and distal portions; scraping at the distal portion; scraping at the proximal portion; scraping at the proximal and distal portions; perforation of the husk with a soldering-iron; and perforation by pyrography. In the second experiment, with a completely randomized design and factorial 2 (heat: dry and wet) x 4 (temperature: 40ÂșC, 50ÂșC, 60ÂșC and 70ÂșC) x 5 (period of conditioning: 6, 16, 24, 30 and 48 hours), with three repetitions. The clipping or scraping of the seeds in the proximal portion and proximal and distal portions allowed faster imbibition of the seeds (143-163% in three days and half), and consequently, better germination (98-100% in four days), germination speed rate (1,351-1,460) and average time of germination (3 days). The pre-treatment with heat (wet and dry), under different temperatures and different conditioning periods did not overcome the dormancy of P. discolor seeds.O presente trabalho teve como objetivo avaliar os efeitos da aplicação de tratamentos prĂ©-germinativos de escarificação mecĂąnica, bem como prĂ©-tratamentos com calor, sobre a germinação de sementes de visgueiro-do-igapĂł (Parkia discolor Spruce ex Benth.). No primeiro experimento, sob delineamento inteiramente ao acaso, com quatro repetiçÔes, foram avaliados os prĂ©-tratamentostestemunha (sem prĂ©-tratamento); desponte no lado distal; desponte no lado proximal; desponte nos lados distal e proximal; lixamento no lado distal; lixamento no lado proximal; lixamento nos lados distal e proximal; perfuração do tegumento com ferro-de-solda; e perfuração com pirĂłgrafo. No segundo experimento, foi adotado o delineamento inteiramente casualizado, em esquema fatorial 2 (calorseco e Ășmido) x 4 (temperatura40ÂșC, 50ÂșC, 60ÂșC e 70ÂșC) x 5 (perĂ­odo de condicionamento6, 16, 24, 30 e 48 horas), com trĂȘs repetiçÔes. O desponte ou lixamento das sementes na porção proximal e porçÔes proximal e distal possibilitaram uma embebição mais rĂĄpida (143-163%, aos trĂȘs dias e meio) e, conseqĂŒentemente, melhores resultados de germinação (98-100%, aos quatro dias), do Ă­ndice de velocidade de germinação (1,351-1,460) e do tempo mĂ©dio de germinação (3 dias). Os prĂ©-tratamentos com calor (Ășmido e seco), sob diferentes temperaturas, e por vĂĄrios perĂ­odos de condicionamento nĂŁo superaram a dormĂȘncia de sementes de P. discolor

    Evaluation of basil extract ( Ocimum basilicum L.) on oxidative, anti-genotoxic and anti-inflammatory effects in human leukocytes cell cultures exposed to challenging agents

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    ABSTRACT Ocimum is one of the most important genera of the Lamiaceae family. Several studies about basil and its popular use reveal many characteristics of the herb, including its use as antioxidant, anti-aging, anti-inflammatory, anti-carcinogenic, anti-microbial, and cardiovascular agents, among others. In this paper, we evaluated genotoxic, oxidative, and anti-inflammatory parameters from the extract of Ocimum basilicum in different concentrations, using human leukocytes cultures exposed to challenging agents. Our results confirm that the O. basilicum extract acts as an antioxidant and effectively reverts or subjugates the effects of high oxidizing agents such as hydrogen peroxide. These actions are attributed to its composition, which is rich in polyphenols and flavonoids as well as compounds such as rosmarinic acid, all of which have well-known antioxidant activity. We also show that our basil extract presents anti-inflammatory properties, the mechanism of which is a composed interaction between the inhibition of pro-inflammatory mediator and the stimulation of anti-inflammatory cytokines. Although pharmacodynamics studies are necessary to evaluate the activities in vivo, our results demonstrated that basil could act as an antioxidant and anti-inflammatory and a possible alternative for medicinal treatment
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