503 research outputs found

    In vitro effects of regulators on growth and morphogenesis of Ocimum basilicum L. ‘Alfavaca Green’ stem apexes

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    Large-scale cultivation of contamination free plants requires a good standardization protocol and production methods. Basil is widely used for cosmetics, food and pharmaceutical industries as it is rich in many bioactive compounds. This present study aimed to evaluate the growth and in vitro anatomical aspects of apical buds of basil grown under different concentrations rowth regulators like: NAA (Naphthalenoacetic Acid), BAP (6-benzylaminopurine), and KIN (Kinetin). The in vitro establishment was evaluated every 20 days to calculate the, the percentage of plants with calluses, appearance of the roots, any abnormal seedlings, any oxidized seedlings, and the number of sprouts per plant. Growth, physiological, and morpho-anatomical evaluations were performed at 80 days. Basal callogenesis was observed when cytokinin’s and auxins are used in combination. Auxin treatments caused hyperhydricity in the stems and leaves. Medium A2 (0.05 mg L -1 of NAA and 0.1 mg L -1 of BAP), and A3 (0.05 mg L -1 of NAA and 0.1 mg L -1 of KIN) resulted in the best development of basil plants, cultivar ‘Alfavaca Green’. The A2 produced plants with greater numbers of leaves, an average bud length of 59.81 mm, and the best root properties. A2 and A1 have a higher percentage of hyperhydricity (83 and 67%). The A3 resulted in an acceptable number of leaves (range: 21–39), and this treatment produced the best shoot properties as well as fewer plants with hyperhydricity. In addition, the A3 treatment produced plants with a shoot length, high shoot fresh and dry mass (2.82 and 0.23 g), high chlorophyll index and leaf anatomy that was similar to the control. Excluding the control, the other treatments presented more than 90% of the explants with calluses in their bases

    Selection of strawberry cultivars with tolerance to Tetranychus urticae (Acari: Tetranychidae) and high yield under different managements.

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    Tetranychus urticae Koch (Acari: Tetranychidae) is considered the main pest of strawberry. Several factors can favor its development, among them the genotype susceptibility and cropping system. The aims of this study were to evaluate the agronomic performance of strawberry cultivars under different managements and to identify strawberry cultivars that meet tolerance to T. urticae and high fruit yield. Thirteen cultivars of strawberry ('Albion', 'Aleluia', 'Aromas', 'Camarosa', 'Camino Real', 'Campinas', 'Diamante', 'Dover', 'Festival', 'Seascape', 'Toyonoka', 'Tudla', and 'Ventana') under three managements (open field, low tunnel, and high tunnel) were evaluated. The T. urticae attack to different cultivars was influenced by managements, being low tunnel the one that provided higher infestations in the most evaluated cultivars. 'Camarosa' was the cultivar with the lower incidence of pest and 'Dover' had the higher infestation. The genotype most suitable for growing under different managements is the 'Festival' genotype, since it meets tolerance to T. urticae, high fruit yield, and phenotypic stability

    Radiation recoil from highly distorted black holes

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    We present results from numerical evolutions of single black holes distorted by axisymmetric, but equatorially asymmetric, gravitational (Brill) waves. Net radiated energies, apparent horizon embeddings, and recoil velocities are shown for a range of Brill wave parameters, including both even and odd parity distortions of Schwarzschild black holes. We find that a wave packet initially concentrated on the black hole throat, a likely model also for highly asymmetric stellar collapse and late stage binary mergers, can generate a maximum recoil velocity of about 150 (23) km/sec for even (odd) parity perturbations, significantly less than that required to eject black holes from galactic cores.Comment: 15 pages, 8 figure

    Economic efficiency and productivity of life-cycle beef cattle production systems in the South of Bahia

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    Estudaram-se a produtividade e a eficiência econômica de quatro sistemas de bovinos de corte, por meio de simulação, que diferiram quanto à taxa de natalidade (TN). A pesquisa foi realizada em uma fazenda de ciclo completo (SCC) com TN de 87%, e mais três sistemas simulados: -4TN com TN de 83%; -2TN com TN de 85%; e +2TN com TN de 89%. O SCC foi baseado em dados de um sistema de cria, recria e engorda com média de 3.453 cabeças, localizado no sul da Bahia, no período de janeiro de 2000 a dezembro de 2002. As TN foram ajustadas à demanda energética dos animais em cada sistema e à evolução do rebanho durante três anos. A quantidade de carne vendida foi de 149, 146, 144, 141 kg/ha/ano para -4TN, -2TN, SCC e +2TN, respectivamente. O lucro total acumulado, na mesma ordem de citação, foi de R780.695,42;R780.695,42; R737.526,16; R727.031,52eR727.031,52 e R703.907,58. O retorno do capital investido acumulado foi de 7,8; 7,4; 7,3 e 7,0% para -4 TN, -2TN, SCC e +2TN, respectivamente. A variação da TN na atividade de cria, recria e engorda de bovinos alterou a produtividade e a eficiência econômica dos sistemas simulados. As respostas em produtividade e eficiência econômica diminuíram com o aumento da taxa de natalidade.Economic efficiency and productivity of life-cycle cattle raising systems were studied by simulations that differed in calving rates (CR). The study was conducted on a life-cycle cattle production system (SCC) with 87% CR, and three simulated systems: -4CR with 83% CR, -2CR with 85% CR, and +2CR with 89% CR. The SCC was based on data from a life-cycle cattle system of 3,453 animals in the South of Bahia State, from January 2000 to December 2002. CR was adjusted according to energy requirement and herd composition in SCC during three years. Meat amount sold was 149, 146, 144, and 141kg/ha/year for -4CR, -2CR, SCC, and +2CR, respectively. Accumulated profit and return on invested capital were R780,695.42and7.8 780,695.42 and 7.8%; R 737,526.16 and 7.4%; R727,031.52and7.3 727,031.52 and 7.3%; and R 703,907.58 and 7.0% for -4CR, -2CR, SCC, and +2CR, respectively. Calving rate variation modified the economic efficiency and productivity of simulated production systems. Economic efficiency and productivity results decreased as calving rate increased

    Dynamic Scaling in Diluted Systems Phase Transitions: Deactivation trough Thermal Dilution

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    Activated scaling is confirmed to hold in transverse field induced phase transitions of randomly diluted Ising systems. Quantum Monte Carlo calculations have been made not just at the percolation threshold but well bellow and above it including the Griffiths-McCoy phase. A novel deactivation phenomena in the Griffiths-McCoy phase is observed using a thermal (in contrast to random) dilution of the system.Comment: 4 pages, 4 figures, RevTe

    In silico analysis of cytochrome p450 genes involved in the metabolism of diterpenes in Coffea.

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    Brazil is the largest world producer and exporter of coffee, being also the second largest consumer market. Among the main goals of coffee breeders, studies aiming the improvement of cup quality and plant tolerance to biotic and abiotic stresses have extreme importance. Beverage nutraceutical properties and plant defense mechanisms are directly linked to diterpenes present in the lipid fraction of coffee beans, such as cafestol (Caf ) and caveol (Cav). Many members of P 450 gene family are involved in plant secondary metabolism, including diterpenes synthesis. In order to depict biochemical and genetic aspects of diterpenes byosinthesis, we did an in silico characterization of p450 gene family in Coffea spp., and we also quantified Caf and Cav in coffee fruit tissues for further gene expression studies involving diterpens metabolism. Using keyword and Blast search, 1396 ESTs related to Cyt p450 were selected from the Brazilian Coffee Genome Project (http://www.lge.ibi. unicamp.br/cafe). After assembling, we observed 157 putative unigenes, distributed in 92 contigs and 65 singlets. The contigs were analyzed using BLAST X versus public sequences databases (GenBank and Harvest Coffea), confirming their identity to 91 Cyt P450 genes. Expression profiles were inferred by electronic Northern blot of all contigs, allowing the selection of 7 candidate genes for transcriptional analysis based in fruit cDNA library expression. Caf and Cav were measured using HPLC in two different fruit developmental stages: 90 DAF (Days After Flowering) vs 120 DAF and in fruits (120 DAF) treated with 2?M methyl Jasmonate (MJ). Fruits at 120 DAF had an increase of 42% in Cav and 19% in Caf levels in relation to 90DAF fruits. MJ treatment resulted in samples with an average increase of 18% of Cav and 35% of Caf. RNAs were extracted from these samples for future transcriptional analyses. This study establish a platform for expression analysis of cyt P450 candidate genes in RNA samples from tissues with contrasting accumulation of Cav and Caf. (Texte intégral

    On the critical behavior of disordered quantum magnets: The relevance of rare regions

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    The effects of quenched disorder on the critical properties of itinerant quantum antiferromagnets and ferromagnets are considered. Particular attention is paid to locally ordered spatial regions that are formed in the presence of quenched disorder even when the bulk system is still in the paramagnetic phase. These rare regions or local moments are reflected in the existence of spatially inhomogeneous saddle points of the Landau-Ginzburg-Wilson functional. We derive an effective theory that takes into account small fluctuations around all of these saddle points. The resulting free energy functional contains a new term in addition to those obtained within the conventional perturbative approach, and it comprises what would be considered non-perturbative effects within the latter. A renormalization group analysis shows that in the case of antiferromagnets, the previously found critical fixed point is unstable with respect to this new term, and that no stable critical fixed point exists at one-loop order. This is contrasted with the case of itinerant ferromagnets, where we find that the previously found critical behavior is unaffected by the rare regions due to an effective long-ranged interaction between the order parameter fluctuations.Comment: 16 pp., REVTeX, epsf, 2 figs, final version as publishe

    Quantum Griffiths effects and smeared phase transitions in metals: theory and experiment

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    In this paper, we review theoretical and experimental research on rare region effects at quantum phase transitions in disordered itinerant electron systems. After summarizing a few basic concepts about phase transitions in the presence of quenched randomness, we introduce the idea of rare regions and discuss their importance. We then analyze in detail the different phenomena that can arise at magnetic quantum phase transitions in disordered metals, including quantum Griffiths singularities, smeared phase transitions, and cluster-glass formation. For each scenario, we discuss the resulting phase diagram and summarize the behavior of various observables. We then review several recent experiments that provide examples of these rare region phenomena. We conclude by discussing limitations of current approaches and open questions.Comment: 31 pages, 7 eps figures included, v2: discussion of the dissipative Ising chain fixed, references added, v3: final version as publishe
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