2,030 research outputs found
Global large solutions to 3-D inhomogeneous Navier-Stokes system with one slow variable
In this paper, we are concerned with the global wellposedness of 3-D
inhomogeneous incompressible Navier-Stokes equations \eqref{1.3} in the
critical Besov spaces with the norm of which are invariant by the scaling of
the equations and under a nonlinear smallness condition on the isentropic
critical Besov norm to the fluctuation of the initial density and the critical
anisotropic Besov norm of the horizontal components of the initial velocity
which have to be exponentially small compared with the critical anisotropic
Besov norm to the third component of the initial velocity. The novelty of this
results is that the isentropic space structure to the homogeneity of the
initial density function is consistent with the propagation of anisotropic
regularity for the velocity field. In the second part, we apply the same idea
to prove the global wellposedness of \eqref{1.3} with some large data which are
slowly varying in one direction
The pollen receptor kinase LePRK2 mediates growth-promoting signals and positively regulates pollen germination and tube growth
In flowering plants, the process of pollen germination and tube growth is required for successful fertilization. A pollen receptor kinase from tomato (Solanum lycopersicum), LePRK2, has been implicated in signaling during pollen germination and tube growth as well as in mediating pollen (tube)-pistil communication. Here we show that reduced expression of LePRK2 affects four aspects of pollen germination and tube growth. First, the percentage of pollen that germinates is reduced, and the time window for competence to germinate is also shorter. Second, the pollen tube growth rate is reduced both in vitro and in the pistil. Third, tip-localized superoxide production by pollen tubes cannot be increased by exogenous calcium ions. Fourth, pollen tubes have defects in responses to style extract component (STIL), an extracellular growth-promoting signal from the pistil. Pollen tubes transiently overexpressing LePRK2-fluorescent protein fusions had slightly wider tips, whereas pollen tubes coexpressing LePRK2 and its cytoplasmic partner protein KPP (a Rop-GEF) had much wider tips. Together these results show that LePRK2 positively regulates pollen germination and tube growth and is involved in transducing responses to extracellular growth-promoting signals.Fil: Zhang, Dong. Chinese Academy of Sciences; República de ChinaFil: Wengier, Diego Leonardo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en IngenierÃa Genética y BiologÃa Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de FisiologÃa, BiologÃa Molecular y Celular. Laboratorio de FisiologÃa y BiologÃa Molecular; Argentina. University of California at Berkeley; Estados UnidosFil: Shuai, Bin. University of California at Berkeley; Estados UnidosFil: Gui, Cai Ping. Chinese Academy of Sciences; República de ChinaFil: Muschietti, Jorge Prometeo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en IngenierÃa Genética y BiologÃa Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de FisiologÃa, BiologÃa Molecular y Celular. Laboratorio de FisiologÃa y BiologÃa Molecular; ArgentinaFil: McCormick, Sheila. University of California at Berkeley; Estados UnidosFil: Tang, Wei Hua. Chinese Academy of Sciences; República de China. University of California at Berkeley; Estados Unido
A coordination polymer of CdII with benzene-1,3-dicarboxylÂate and 1,4-bisÂ[1-(2-pyridylmethÂyl)benzimidazol-2-yl]butane
The title CdII coordination polymer, catena-poly[[{1,4-bisÂ[1-(2-pyridylmethÂyl)benzimidazol-2-yl]butane}cadmium(II)]-μ-benzene-1,3-dicarboxylÂato], [Cd(C8H4O4)(C30H28N6)]n, was obtained by reaction of CdCO3, benzene-1,3-dicarboxylic acid (H2btc) and 1,4-bisÂ[1-(2-pyridylmethÂyl)benzimidazol-2-yl]butane (L). The CdII cation is six-coordinated by an N2O4-donor set. L acts as a bidentate ligand and btc anions link CdII centers into a chain propagating parallel to [010]
Lattice study on and X(3872)
Properties of charmonium are investigated in quenched
lattice QCD. The mass of is determined to be 3.80(3) GeV, which is
close to the mass of -wave charmonium and in agreement with
quark model predictions. The transition width of
is also obtained with a value keV. Since the possible
assignment to X(3872) has not been ruled out by experiments, our results help
to clarify the nature of X(3872).Comment: 15 pages, 8 figures. typos, grammatical errors and some references
corrected, redundant discussions deleted, conclusion does not change.
published versio
Quantum control of two interacting electrons in a coupled quantum dot
Quantum-state engineering, i.e., active manipulation over the coherent
dynamics of suitable quantum-mechanical systems, has become a fascinating
prospect of modern physics. Here we discuss the dynamics of two interacting
electrons in a coupled quantum dot driven by external electric field. We show
the two quantum dots can be used to prepare maximally entangled Bell state by
varying the strength and duration of an oscillatory electric field. Different
from suggestion given by Loss \QTR{it}{et al}.[Phys. Rev. A, \QTR{bf}{57}
(1998) 120], the present entanglement involves the spatial degree of freedom
for the two electrons. We also find that the coherent tunneling suppression
discussed by Grossmann \QTR{it}{et al}.[Phys. Rev. Lett., \QTR{bf}{67} (1991)
516] persists in the two-particle case, i.e., two electrons initially localized
in one dot can remain dynamically localized, although the strong Coulomb
repulsion prevents them behaving so. Surprisingly, the interaction enhances the
degree of localization to a larger extent compared to non-interacting case. We
can call this phenomenon Coulomb-enhanced dynamical localization.Comment: 9 pages, 10 figure
A compositional approach for traffic distribution evaluation of triple left-turn lanes from an individual perspective
This study analysed unbalanced traffic distribution on Triple Left-Turn Lanes (TLTLs) at signalized intersections that is caused by left-turn drivers’ unequal lane preferences. To develop statistical bonding between the multilane traffic flow and individual lane choices, the lane volumes are formatted as compositional data to subject the sum-constant constraint. One-way and two-way Compositional ANalysis Of VAriance (CANOVA) models were formulated respectively to estimate the independent effect of one factor and its joint effects with other factors on the multilane traffic distribution. TLTL volume composition was the dependent variable of the models, while the factors of geometric design and traffic control that could affect left-turn drivers’ lane choice were the independent variables. Results indicate that variance of vehicle turning curve, length of the upstream segment, the location of triple left-turn sign, signal phase / cycle length, could affect the traffic distribution, and its balance could be achieved at specific levels of a factor. The joint effects of some factor couples could improve the unbalanced traffic distribution while others could not work
- …