11,883 research outputs found
Orbital Perturbations of the Galilean Satellites During Planetary Encounters
The Nice model of the dynamical instability and migration of the giant
planets can explain many properties of the present Solar System, and can be
used to constrain its early architecture. In the jumping-Jupiter version of the
Nice model, required from the terrestrial planet constraint and dynamical
structure of the asteroid belt, Jupiter has encounters with an ice giant. Here
we study the survival of the Galilean satellites in the jumping-Jupiter model.
This is an important concern because the ice-giant encounters, if deep enough,
could dynamically perturb the orbits of the Galilean satellites, and lead to
implausible results. We performed numerical integrations where we tracked the
effect of planetary encounters on the Galilean moons. We considered three
instability cases from Nesvorny & Morbidelli (2012) that differed in the number
and distribution of encounters. We found that in one case, where the number of
close encounters was relatively small, the Galilean satellite orbits were not
significantly affected. In the other two, the orbital eccentricities of all
moons were excited by encounters, Callisto's semimajor axis changed, and, in a
large fraction of trials, the Laplace resonance of the inner three moons was
disrupted. The subsequent evolution by tides damps eccentricities and can
recapture the moons in the Laplace resonance. A more important constraint is
represented by the orbital inclinations of the moons, which can be excited
during the encounters and not appreciably damped by tides. We find that one
instability case taken from Nesvorny & Morbidelli (2012) clearly fails this
constraint. This shows how the regular satellites of Jupiter can be used to set
limits on the properties of encounters in the jumping-Jupiter model, and help
us to better understand how the early Solar System evolved.Comment: The Astronomical Journal, in pres
Large scale CMB anomalies from thawing cosmic strings
Cosmic strings formed during inflation are expected to be either diluted over
super-Hubble distances, i.e., invisible today, or to have crossed our past
light cone very recently. We discuss the latter situation in which a few
strings imprint their signature in the Cosmic Microwave Background (CMB)
Anisotropies after recombination. Being almost frozen in the Hubble flow, these
strings are quasi static and evade almost all of the previously derived
constraints on their tension while being able to source large scale
anisotropies in the CMB sky. Using a local variance estimator on thousand of
numerically simulated Nambu-Goto all sky maps, we compute the expected signal
and show that it can mimic a dipole modulation at large angular scales while
being negligible at small angles. Interestingly, such a scenario generically
produces one cold spot from the thawing of a cosmic string loop. Mixed with
anisotropies of inflationary origin, we find that a few strings of tension GU =
O(1) x 10^(-6) match the amplitude of the dipole modulation reported in the
Planck satellite measurements and could be at the origin of other large scale
anomalies.Comment: 23 pages, 11 figures, uses jcappub. References added, matches
published versio
Role of strong correlation in the recent ARPES experiments for cuprate superconductors
Motivated by recent photoemission experiments on cuprates, the low-lying
excitations of a strongly correlated superconducting state are studied
numerically. It is observed that along the nodal direction these low-lying
one-particle excitations show a linear momentum dependence for a wide range of
excitation energies and, thus, they do not present a kink-like structure. The
nodal Fermi velocity , as well as other observables, are
systematically evaluated directly from the calculated dispersions, and they are
found to compare well with experiments. It is argued that the parameter
dependence of is quantitatively explained by a simple picture of a
renormalized Fermi velocity.Comment: 5 pages, 4 figures, to be published in Phys. Rev. Let
Endotoxemia and human liver transplantation
Ninety liver transplantations were performed in 81 patients. Plasma endotoxin was measured preoperatively, at the end of the anhepatic phase, and on postoperative days 1, 3, and 7. The presence of high endotoxin levels preoperatively and at the end of the anhepatic period was associated with graft failure and a high mortality. Patients with primary nonfunction of their transplants typically had severe endotoxemia. Endotoxemia could be a cause rather than an effect of perioperative complications and graft loss
The inverse problem of the optimal regulator
Inverse problem of optimal regulator for class of systems with integral type performance indice
Unitarity, Crossing Symmetry and Duality of the S-matrix in large N Chern-Simons theories with fundamental matter
We present explicit computations and conjectures for scattering
matrices in large {\it } Chern-Simons theories coupled to fundamental
bosonic or fermionic matter to all orders in the 't Hooft coupling expansion.
The bosonic and fermionic S-matrices map to each other under the recently
conjectured Bose-Fermi duality after a level-rank transposition. The S-matrices
presented in this paper may be regarded as relativistic generalization of
Aharonov-Bohm scattering. They have unusual structural features: they include a
non analytic piece localized on forward scattering, and obey modified crossing
symmetry rules. We conjecture that these unusual features are properties of
S-matrices in all Chern-Simons matter theories. The S-matrix in one of the
exchange channels in our paper has an anyonic character; the parameter map of
the conjectured Bose-Fermi duality may be derived by equating the anyonic phase
in the bosonic and fermionic theories.Comment: 66 pages+ 45 pages appendices, 20 figures, Few typos corrected and
few references adde
Long-term dynamics of Methone, Anthe and Pallene
We numerically investigate the long-term dynamics of the Saturn's small
satellites Methone (S/2004 S1), Anthe (S/2007 S4) and Pallene (S/2004 S2). In
our numerical integrations, these satellites are disturbed by non-spherical
shape of Saturn and the six nearest regular satellites. The stability of the
small bodies is studied here by analyzing long-term evolution of their orbital
elements.
We show that long-term evolution of Pallene is dictated by a quasi secular
resonance involving the ascending nodes () and longitudes of
pericentric distances () of Mimas (subscript 1) and Pallene (subscript
2), which critical argument is . Long-term
orbital evolution of Methone and Anthe are probably chaotic since: i) their
orbits randomly cross the orbit of Mimas in time scales of thousands years);
ii) numerical simulations involving both small satellites are strongly affected
by small changes in the initial conditions.Comment: 9 pages; 4 figures. Submitted to Proceedings IAU Symposium No. S263,
200
High-Potential C112D/M121X (X = M, E, H, L) Pseudomonas aeruginosa Azurins
Site-directed mutagenesis of Pseudomonas aeruginosa azurin
C112D at the M121 position has afforded a series of proteins with
elevated Cu^(II/I) reduction potentials relative to the CuII aquo ion.
The high potential and low axial hyperfine splitting (Cu^(II) electron
paramagnetic resonance A|) of the C112D/M121L protein are
remarkably similar to features normally associated with type 1
copper centers
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