4,295 research outputs found
Updates of effects on CP angles determination in B decays
The recently observed CP violation in B decay and -\ovar{B} mixing data
put constraints on the mass of and the parameters of the right-handed
current quark mixing matrix in gauge
model. It is shown that the allowed region of parameters are severely
restricted for light with mass on the order of 1 TeV. There exist sets of
parameters which can accommodate large CP violation as measured by Belle,
, for TeV.Comment: 11pages, 19 figures, LaTeX2
Unknotting numbers and triple point cancelling numbers of torus-covering knots
It is known that any surface knot can be transformed to an unknotted surface
knot or a surface knot which has a diagram with no triple points by a finite
number of 1-handle additions. The minimum number of such 1-handles is called
the unknotting number or the triple point cancelling number, respectively. In
this paper, we give upper bounds and lower bounds of unknotting numbers and
triple point cancelling numbers of torus-covering knots, which are surface
knots in the form of coverings over the standard torus . Upper bounds are
given by using -charts on presenting torus-covering knots, and lower
bounds are given by using quandle colorings and quandle cocycle invariants.Comment: 26 pages, 14 figures, added Corollary 1.7, to appear in J. Knot
Theory Ramification
Occurrence Distribution of Polar Cap Patches: Dependences on UT, Season and Hemisphere
Polar cap patches are islands of enhanced electron density in the polar cap F region ionosphere, which sometimes affect the propagation of trans-ionospheric radio waves. Considering the intake of daytime sunlit plasma by the high-latitude convection as the primary cause of patches, the spatial overlap between the convection and the daytime sunlit plasma should be one of the critical factors controlling the generation of patches. To confirm this hypothesis, we statistically investigated the UT and seasonal distributions of patch occurrence frequency in both the hemispheres by using in situ plasma density data from the Swarm satellite. As a result, it was found that the occurrence distribution of patches is a complex function of UT, season and hemisphere, but it can be mostly interpreted by the spatial overlap between the high-latitude convection and the solar terminator. This suggests that polar cap patches are not necessarily phenomena that occur only during winter months. That is, patches can often be observed even in periods away from the winter solstice if the location of solar terminator in the magnetic coordinate system is appropriate for the generation of patches. For example, in the southern hemisphere, where the offset between the geographic and magnetic poles is larger than that in the northern hemisphere, the highest patch occurrence rate is obtained around the equinoctial periods. These results indicate that it is needed to take these dependences into account when we discuss and predict the space weather impacts of patches on the trans-ionospheric radio propagation
Theoretical Models of Multi-waveband QSO Luminosity Functions
Cosmological evolution of the QSO luminosity functions (LFs) at
NIR/optical/X-ray bands for 1.3 < z < 3.5 is investigated based on the
realistic QSO spectra. The accretion-disk theory predicts that although QSO
luminosities only depend on mass-accretion rate, \Mdot, QSO spectra have a
dependence on black-hole mass, M_{BH}, as well. The smaller M_{BH} is and/or
the larger \Mdot is, the harder becomes the QSO NIR/optical/UV spectrum. We
model disk spectra which can reproduce these features and calculated LFs for
redshift z ~ 3 with the assumption of new-born QSOs being shining at the
Eddington luminosity. The main results are: (i) the observed LFs at optical and
X-rays can be simultaneously reproduced. (ii) LFs at optical and X-ray bands
are not sensitive to M_{BH}, while LFs at NIR bands are; about one order of
magnitude difference is expected in volume number densities at L_{I, J} ~
10^{46} erg s^{-1} between the case that all QSOs would have the same spectral
shape as that of M_{BH} = 10^{9} M_sun and the case with M_{BH} = 10^{11}
M_sun. (iii) The resultant LFs at NIR are dominated by 10^{7} M_sun black-holes
at L_{I, J} ~ 10^{44} erg s^{-1}, and by 10^{11} M_sun black-holes at L_{I, J}
\~ 10^{46} erg s^{-1}. Future infrared observations from space(e.g.NGST) will
probe cosmological evolution of black hole masses. For redshift z < 3, on the
other hand, the observed optical/X-ray LFs can be fitted, if the initial QSO
luminosity L_0 is below the Eddington luminosity. Interestingly, the best
fitting values of l = L_0/L_{Edd} are different in B- and X-ray bands; l_B ~
2.5 l_X. The reason for this discrepancy is briefly discussed.Comment: 10 pages,7 Figures,to be published in Publications of the
Astronomical Society of Japa
Clinical neurophysiological assessment of sepsis-associated brain dysfunction: a systematic review.
IntroductionSeveral studies have reported the presence of electroencephalography (EEG) abnormalities or altered evoked potentials (EPs) during sepsis. However, the role of these tests in the diagnosis and prognostic assessment of sepsis-associated encephalopathy remains unclear.MethodsWe performed a systematic search for studies evaluating EEG and/or EPs in adult (¿18 years) patients with sepsis-associated encephalopathy. The following outcomes were extracted: a) incidence of EEG/EP abnormalities; b) diagnosis of sepsis-associated delirium or encephalopathy with EEG/EP; c) outcome.ResultsAmong 1976 citations, 17 articles met the inclusion criteria. The incidence of EEG abnormalities during sepsis ranged from 12% to 100% for background abnormality and 6% to 12% for presence of triphasic waves. Two studies found that epileptiform discharges and electrographic seizures were more common in critically ill patients with than without sepsis. In one study, EEG background abnormalities were related to the presence and the severity of encephalopathy. Background slowing or suppression and the presence of triphasic waves were also associated with higher mortality. A few studies demonstrated that quantitative EEG analysis and EP could show significant differences in patients with sepsis compared to controls but their association with encephalopathy and outcome was not evaluated.ConclusionsAbnormalities in EEG and EPs are present in the majority of septic patients. There is some evidence to support EEG use in the detection and prognostication of sepsis-associated encephalopathy, but further clinical investigation is needed to confirm this suggestion
Statistical Description of Hydrodynamic Processes in Ionic Melts with taking into account Polarization Effects
Statistical description of hydrodynamic processes for ionic melts is proposed
with taking into account polarization effects caused by the deformation of
external ionic shells. This description is carried out by means of the Zubarev
nonequilibrium statistical operator method, appropriate for investigations of
both strong and weak nonequilibrium processes. The nonequilibrium statistical
operator and the generalized hydrodynamic equations that take into account
polarization processes are received for ionic-polarization model of ionic
molten salts when the nonequilibrium averaged values of densities of ions
number, their momentum, dipole momentum and total energy are chosen for the
reduced description parameters. A spectrum of collective excitations is
investigated within the viscoelastic approximation for ion-polarization model
of ionic melts.Comment: 24 pages, RevTex4.1-format, no figure
Charge density wave soliton liquid
We investigate the charge density wave transport in a quasi-one-dimensional
conductor, orthorhombic tantalum trisulfide (-TaS), by applying a
radio-frequency ac voltage. We find a new ac-dc interference spectrum in the
differential conductance, which appear on both sides of the zero-bias peak. The
frequency and amplitude dependences of the new spectrum do not correspond to
those of any usual ac-dc interference spectrum (Shapiro steps). The results
suggest that CDW phase dynamics has a hidden degree of freedom. We propose a
model in which phase solitons behave as liquid. The origin of the new
spectrum is that the solitons are depinned from impurity potentials assisted by
an ac field when small dc field is applied. Our results provide a new insight
as regards our understanding of an elementary process in CDW dynamics.Comment: 16 pages, 5 figure
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