2,237 research outputs found
Structure-activity relationships of synthetic analogs of jasmonic acid and coronatine on induction of benzo[c]phenanthridine alkaloid accumulation in Eschscholzia californica cell cultures
A facile test system based on the accumulation of benzo[c]phenanthridine alkaloids in Eschscholzia californica cell suspension culture (an indicator of defense gene activation) has been used to analyze a series of synthetic compounds for elicitor-like activity. Of the 200 jasmonic acid and coronatine analogs tested with this system, representative results obtained with 49 of them are presented here. The following can be summarized concerning structure-actvity relationships: there is a large degree of plasticity allowed at the C-3 of jasmonic acid in the activation of defense genes. The carbonyl moiety is not strictly required, but exocyclic double bond character appears necessary. The pentenyl side chain at C-2 cannot tolerate bulky groups at the terminal carbon and still be biologically active. Substitutions to the C-1' position are tolerated if they can potentially undergo beta-oxidation. Either an alkanoic acid or methyl ester is required at c-l, or a side chain that can be shortened by beta-oxidation or by peptidase hydrolysis. Coronatine and various derivatives thereof are not as effective as jasmonic acid, and derivatives in inducing benzo[c]phenanthridine alkaloid accumulation. Jasmonic acid rather than the octadecanoic precursors is therefore considered to be a likely signal transducer of defense gene activation in planta
Hyperbolic Kac-Moody superalgebras
We present a classification of the hyperbolic Kac-Moody (HKM) superalgebras.
The HKM superalgebras of rank larger or equal than 3 are finite in number (213)
and limited in rank (6). The Dynkin-Kac diagrams and the corresponding simple
root systems are determined. We also discuss a class of singular
sub(super)algebras obtained by a folding procedure
Pressure-induced phase transition and bi-polaronic sliding in a hole-doped Cu_2O_3 ladder system
We study a hole-doped two-leg ladder system including metal ions, oxygen, and
electron-lattice interaction, as a model for Sr_{14-x}Ca_xCu_{24}O_{41-\delta}.
Single- and bi-polaronic states at 1/4-hole doping are modeled as functions of
pressure by applying an unrestricted Hartree-Fock approximation to a multiband
Peierls-Hubbard Hamiltonian. We find evidence for a pressure-induced phase
transition between single-polaron and bi-polaron states. The electronic and
phononic excitations in those states, including distinctive local lattice
vibrational modes, are calculated by means of a direct-space Random Phase
approximation. Finally, as a function of pressure, we identify a transition
between site- and bond-centered bi-polarons, accompanied by a soft mode and a
low-energy charge-sliding mode. We suggest comparisons with available
experimented data
"Avaliação da higienização do resÃduo de caixa de areia de estações de tratamento de esgoto"
O processo de tratamento de esgoto doméstico gera resÃduos sólidos que precisam ser constantemente removidos afim de se manter a eficiência do tratamento, dentre eles, o resÃduo depositado no fundo das caixas de areia. A caixa de areia tem como objetivo remover do esgoto areia e outras partÃculas, incluindo as orgânicas, presentes no esgoto in natura, que através do processo de sedimentação são arrastadas para o fundo. Apesar de não receber a devida importância, uma vez que a prática é enterrar este resÃduo em valas ou dispor no solo sem tratamento, atualmente, este resÃduo passou a ser considerado um problema no gerenciamento de estações no que se refere ao manuseio, tratamento e destinação final, devido a exigências por parte das empresas de saneamento. Visto a necessidade de buscar novas fontes de obtenção de areia, o resÃduo de caixa de areia poderia ser uma opção a ser utilizada na construção civil desde que seja realizada a higienização prévia do material. O objetivo deste trabalho foi avaliar a eficiência da caleagem e da insolação natural na higienização do resÃduo de caixa de areia através da avaliação da redução de bactérias do grupo coliforme e de ovos de helmintos. A metodologia adotada neste trabalho possui 2 etapas. Na primeira etapa, Estudos Preliminares, buscou-se conhecer as caracterÃsticas fÃsicas e microbiológicas da areia, desenvolver procedimentos de coleta e montagem dos experimentos e testar processos de higienização através da caleagem, cloração e insolação natural. Na segunda etapa, Estudo Piloto, avaliou-se a eficiência da caleagem na higienização através da repetição de experimentos. Os resultados obtidos permitiram constatar a eficiência da caleagem na higienização do resÃduo de caixa de areia a partir da dosagem de 10% pode ser considerada eficiente na remoção de bactérias e ovos de helmintos após uma semana de tratamento e a dosagem a partir de 15% eficiente após 48 horas de tratamento e as análises preliminares visando utilizar a areia higienizada demonstram ser viável sua aplicação na construção civil sob o ponto de vista sanitário, e garantem a segurança do manuseio, transporte e destinação final
Vertex Operators, Screen Currents and Correlation Functions at Arbitrary Level
Bosonized q-vertex operators related to the 4-dimensional evaluation modules
of the quantum affine superalgebra are constructed for
arbitrary level , where is a complex parameter
appearing in the 4-dimensional evaluation representations. They are
intertwiners among the level- highest weight Fock-Wakimoto modules.
Screen currents which commute with the action of up to
total differences are presented. Integral formulae for N-point functions of
type I and type II q-vertex operators are proposed.Comment: Latex file 18 page
Anyonic Realization of the Quantum Affine Lie Superalgebra U_q(A(M,N)^{(1)})
We give a realization of the quantum affine Lie superalgebras U_q(A(M,N))^(1)
in terms of anyons defined on a one or two-dimensional lattice, the deformation
parameter q being related to the statistical parameter of the anyons by q
= exp(i\pi\nu). The construction uses anyons contructed from usual fermionic
oscillators and deformed bosonic oscillators. As a byproduct, realization
deformed in any sector of the quantum superalgebras U_q(A(M,N)) is obtained.Comment: 14p LaTeX Document (should be run twice
Level-one Highest Weight Representation of and Bosonization of the Multi-component Super t-J Model
We study the level-one irreducible highest weight representations of the
quantum affine superalgebra , and calculate their
characters and supercharacters. We obtain bosonized q-vertex operators acting
on the irreducible -modules and derive the exchange
relations satisfied by the vertex operators. We give the bosonization of the
multi-component super model by using the bosonized vertex operators.Comment: LaTex file 21 page
Transfer matrix eigenvalues of the anisotropic multiparametric U model
A multiparametric extension of the anisotropic U model is discussed which
maintains integrability. The R-matrix solving the Yang-Baxter equation is
obtained through a twisting construction applied to the underlying Uq(sl(2|1))
superalgebraic structure which introduces the additional free parameters that
arise in the model. Three forms of Bethe ansatz solution for the transfer
matrix eigenvalues are given which we show to be equivalent.Comment: 26 pages, no figures, LaTe
Molecular Clouds associated with the Type Ia SNR N103B in the Large Magellanic Cloud
N103B is a Type Ia supernova remnant (SNR) in the Large Magellanic Cloud
(LMC). We carried out new CO( = 3-2) and CO( = 1-0)
observations using ASTE and ALMA. We have confirmed the existence of a giant
molecular cloud (GMC) at 245 km s towards the
southeast of the SNR using ASTE CO( = 3-2) data at an angular
resolution of 25 (6 pc in the LMC). Using the ALMA CO(
= 1-0) data, we have spatially resolved CO clouds along the southeastern edge
of the SNR with an angular resolution of 1.8 (0.4 pc in the
LMC). The molecular clouds show an expanding gas motion in the
position-velocity diagram with an expansion velocity of km s.
The spatial extent of the expanding shell is roughly similar to that of the
SNR. We also find tiny molecular clumps in the directions of optical nebula
knots. We present a possible scenario that N103B exploded in the wind-bubble
formed by the accretion winds from the progenitor system, and is now
interacting with the dense gas wall. This is consistent with a
single-degenerate scenario.Comment: 12 pages, 1 table, 8 figures, accepted for publication in The
Astrophysical Journal (ApJ
Drinfel'd Realization of Quantum Affine Superalgebra
We obtain Drinfel'd's realization of quantum affine superalgebra
based on the super version of RS construction method and
Gauss decomposition
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