17,931 research outputs found
Q-operator and fusion relations for
The construction of the Q-operator for twisted affine superalgebra
is given. It is shown that the corresponding prefundamental
representations give rise to evaluation modules some of which do not have a
classical limit, which nevertheless appear to be a necessary part of fusion
relations.Comment: 22 p, published versio
Phase Diagram of the 1D Kondo Lattice Model
We determine the boundary of the fully polarized ferromagnetic ground state
in the one dimensional Kondo lattice model at partial conduction electron band
filling by using a newly developed infinite size DMRG method which conserves
the total spin quantum number. The obtained paramagnetic to ferromagnetic phase
boundary is below for the whole range of band filling. By this
we solve the controversy in the phase diagram over the extent of the
ferromagnetic region close to half filling.Comment: 6 pages, 4 EPS figures. Presented at MOS9
Functional Relationships between Kinetic, Flow, and Geometrical Parameters in a High-Temperature Chemical Microreactor.
Computational fluid dynamics (CFD) simulations and isothermal approximation were applied for the interpretation of experimental measurements of the C10H7Br pyrolysis efficiency in the high-temperature microreactor and of the pressure drop in the flow tube of the reactor. Applying isothermal approximation allows the derivation of analytical relationships between the kinetic, gas flow, and geometrical parameters of the microreactor, which, along with CFD simulations, accurately predict the experimental observations. On the basis of the obtained analytical relationships, a clear strategy for measuring rate coefficients of (pseudo) first-order bimolecular and unimolecular reactions using the microreactor was proposed. The pressure- and temperature-dependent rate coefficients for the C10H7Br pyrolysis calculated using variable reaction coordinate transition state theory were invoked to interpret the experimental data on the pyrolysis efficiency
Uterine spiral artery remodeling involves endothelial apoptosis induced by extravillous trophoblasts through Fas/FasL interactions.
Objective— Invasion of uterine spiral arteries by extravillous trophoblasts in the first trimester of pregnancy results in loss of endothelial and musculoelastic layers. This remodeling is crucial for an adequate blood supply to the fetus with a failure to remodel implicated in the etiology of the hypertensive disorder preeclampsia. The mechanism by which trophoblasts induce this key process is unknown. This study gives the first insights into the potential mechanisms involved.
Methods and Results— Spiral arteries were dissected from nonplacental bed biopsies obtained at Caesarean section, and a novel model was used to mimic in vivo events. Arteries were cultured with trophoblasts in the lumen, and apoptotic changes in the endothelial layer were detected after 20 hours, leading to loss of endothelium by 96 hours. In vitro, coculture experiments showed that trophoblasts stimulated apoptosis of primary decidual endothelial cells and an endothelial cell line. This was blocked by caspase inhibition and NOK2, a FasL blocking antibody. NOK2 also abrogated trophoblast-induced endothelial apoptosis in the vessel model.
Conclusions— Extravillous trophoblast induction of endothelial apoptosis is a possible mechanism by which the endothelium is removed, and vascular remodeling may occur in uterine spiral arteries. Fas/FasL interactions have an important role in trophoblast-induced endothelial apoptosis
Long-Term Monitoring of Comet 103P/Hartley 2
We reported the monitoring results on spectrophotometry, photometry and
imaging of comet 103P/Hartley 2 obtained at Lulin (1m), Calar Alto (2.2m) and
Beijing Astronomical (2.16m) Observatory from April to December 2010. We found
that a dust feature at sunward direction was detected starting from the end of
September until the beginning of December (our last observation from the Lulin
and Calar Alto observatory). Two distinct sunward jet features in the processed
images were observed on October 11 and after October 29 until November 2. In
parallel, the CN images reveal two asymmetrical jet features which are nearly
perpendicular to the Sun-nucleus direction and this asymmetrical features
implies that the comet was in a nearly side-on view in late-October and
early-November. Additional to the jet features, the average result of the
C2-to-CN production rate ratio ranges from 0.7 to 1.5 which places 103P/Hartley
2 as being of typical cometary chemistry. We found that the dependence
for the dust production rate, Afrho (5,000 km), is -3.75+-0.45 before
perihelion and is -3.44 +-1.20 during post-perihelion period. We detected the
higher dust reddening is around the optocenter and getting bluer outward along
the sunward jet feature and concluded that the former one, higher dust
reddening, could be associated with strong jet activity and the latter one, the
lowering of the reddening, might imply the optical properties changed or could
be associated with outburst. The average dust color did not appear to vary
significantly as the comet passed through perihelion
CP properties of symmetry-constrained two-Higgs-doublet models
The two-Higgs-doublet model can be constrained by imposing Higgs-family
symmetries and/or generalized CP symmetries. It is known that there are only
six independent classes of such symmetry-constrained models. We study the CP
properties of all cases in the bilinear formalism. An exact symmetry implies CP
conservation. We show that soft breaking of the symmetry can lead to
spontaneous CP violation (CPV) in three of the classes.Comment: 14 pages, 2 tables, revised version adapted to the journal
publicatio
Densities and abundances of hot cometary ions in the coma of P/Halley
On its flight by P/Halley, the Giotto spacecraft carried a High Energy Range Spectrometer (HERS) for measuring the properties of cometary ions picked up by the solar wind in the nearly collisionless regions of the coma. Preliminary estimates of the ion densities observed by HERS were reevaluated and extended; density profiles along the Giotto trajectory are presented for 13 values of ion mass/charge. Comparison with the physical-chemical model of the interaction of sunlight and the solar wind with the comet by other researchers reveals that, with the exception of protons and H2(+), all ion densities were at least an order of magnitude higher than predicted. The high ion densities cannot be explained on the basis of compression of the plasma, but require additional or stronger ionization mechanisms. Ratios of the densities of different ion species reveal an overabundance of carbonaceous material and an underabundance of H2(+) compared to the predictions of the Schmidt. While the densities of solar wind ions (H(+) and He(++)) changed sharply across a magnetic discontinuity located 1.35(10)(exp 5) km from the comet, this feature, which has been called both the 'cometopause' and the 'magnetic pileup boundary' was barely distinguishable in the density profiles of hot cometary ions. This result is consistent with the interpretation that the magnetic pileup boundary detected by Giotto was caused by a discontinuity in the solar wind and is not an intrinsic feature of the interaction of the solar wind with an active comet
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