11,145 research outputs found

    Caracterização morfológica de plântulas de Caryocar villosum (Aubl.) Pers. - Caryocaraceae.

    Get PDF
    O objetivo deste trabalho foi avaliar o desenvolvimento de plântulas da espécie Caryocar villosum (Aubl.) Pers

    Building analytical three-field cosmological models

    Full text link
    A difficult task to deal with is the analytical treatment of models composed by three real scalar fields, once their equations of motion are in general coupled and hard to be integrated. In order to overcome this problem we introduce a methodology to construct three-field models based on the so-called "extension method". The fundamental idea of the procedure is to combine three one-field systems in a non-trivial way, to construct an effective three scalar field model. An interesting scenario where the method can be implemented is within inflationary models, where the Einstein-Hilbert Lagrangian is coupled with the scalar field Lagrangian. We exemplify how a new model constructed from our method can lead to non-trivial behaviors for cosmological parameters.Comment: 11 pages, and 3 figures, updated version published in EPJ

    Cosmological scenarios from multiquintessence

    Full text link
    In this work we derive and analyse cosmological scenarios coming from multi-component scalar field models. We consider a direct sum of a sine-Gordon with a Z2 model, and also a combination of those with a BNRT model. Moreover, we work with a modified version of the BNRT model, which breaks the Z2 x Z2 symmetry of the original BNRT potential, coupled with the sine-Gordon and with the standard Z2 models. We show that our approach can be straightforwardly elevated to NN fields. All the computations are made analytically and some parameters restriction is put forward in order to get in touch with complete and realistic cosmological scenarios

    Thermoconditional modulation of the pleiotropic sensitivity phenotype by the Saccharomyces cerevisiae PRP19 mutant allele pso4-1

    Get PDF
    The conditionally-lethal pso4-1 mutant allele of the spliceosomal-associated PRP19 gene allowed us to study this gene’s influence on pre-mRNA processing, DNA repair and sporulation. Phenotypes related to intron-containing genes were correlated to temperature. Splicing reporter systems and RT–PCR showed splicing efficiency in pso4-1 to be inversely correlated to growth temperature. A single amino acid substitution, replacing leucine with serine, was identified within the N-terminal region of the pso4-1 allele and was shown to affect the interacting properties of Pso4-1p. Amongst 24 interacting clones isolated in a two-hybrid screening, seven could be identified as parts of the RAD2, RLF2 and DBR1 genes. RAD2 encodes an endonuclease indispensable for nucleotide excision repair (NER), RLF2 encodes the major subunit of the chromatin assembly factor I, whose deletion results in sensitivity to UVC radiation, while DBR1 encodes the lariat RNA splicing debranching enzyme, which degrades intron lariat structures during splicing. Characterization of mutagen-sensitive phenotypes of rad2{Delta}, rlf2{Delta} and pso4-1 single and double mutant strains showed enhanced sensitivity for the rad2{Delta} pso4-1 and rlf2{Delta} pso4-1 double mutants, suggesting a functional interference of these proteins in DNA repair processes in Saccharomyces cerevisiae

    Condutitvidade hisráulica do solo coeso dos tabuleiros costeiros cultivado com citros.

    Get PDF
    Avalia através da determinação da condutividade hidráulica não saturada, o movimento de água em agrissolo acinzentado coeso dos tabuleiros costeiros cultivado com citros.bitstream/CPATC/19569/1/bp-22.pdfISSN 1678-1961

    Determinação do grau crítico de umidade em sementes de Cenostigma tocantinum Ducke e Dipteryx odorata Willd.

    Get PDF
    Este trabalho teve como objetivo avaliar o comportamento das sementes desta espécie quanto a sensibilidade à desidratação
    corecore