1,325 research outputs found
Chaos in the Outer Solar System
We study the effect of a perturber on the energy and angular momentum of a test particle on a highly eccentric orbit. We find that both the energy and angular momentum of the test particle are adiabatic invariants when the perturber is on a circular orbit with radius much smaller than the periaps of the test particle. We derive analytical expression for the energy change, or kick, of the test particle with every periaps passage. Using this kick function we formulate mapping for the highly eccentric test particle. We also analyze the stability of resonances and find conditions for asymmetric libration to occur. The resonance widths for highly eccentric orbits are calculated and the criterion for the onset of global chaos is determined
Self-dual SU(2) invariant Einstein metrics and modular dependence of theta-functions
We simplify Hitchin's description of SU(2)-invariant self-dual Einstein
metrics, making use of the tau-function of related four-pole Schlesinger
system.Comment: A wrong sign in the formula for W_1 is corrected; we thank Owen
Dearricott who pointed out this mistake in the original version of the pape
Primordial Bispectrum Information from CMB Polarization
After the precise observations of the Cosmic Microwave Background (CMB)
anisotropy power spectrum, attention is now being focused on the higher order
statistics of the CMB anisotropies. Since linear evolution preserves the
statistical properties of the initial conditions, observed non-Gaussianity of
the CMB will mirror primordial non-Gaussianity. Single field slow-roll
inflation robustly predicts negligible non-Gaussianity so an indication of
non-Gaussianity will suggest alternative scenarios need to be considered. In
this paper we calculate the information on primordial non-Gaussianity encoded
in the polarization of the CMB. After deriving the optimal weights for a cubic
estimator we evaluate the Signal-to-Noise ratio of the estimator for WMAP,
Planck and an ideal cosmic variance limited experiment. We find that when the
experiment can observe CMB polarization with good sensitivity, the sensitivity
to primordial non-Gaussianity increases by roughly a factor of two. We also
test the weakly non-Gaussian assumption used to derive the optimal weight
factor by calculating the degradation factor produced by the gravitational
lensing induced connected four-point function. The physical scales in the
radiative transfer functions are largely irrelevant for the constraints on the
primordial non-Gaussianity. We show that the total (S/N)^2 is simply
proportional to the number of observed pixels on the sky.Comment: To be submitted to PRD, 25 pages, 6 figure
Consistency relation for single scalar inflation
Single scalar field inflation with a generic, non-quadratic in derivatives,
field Lagrangian is considered. It is shown that non-Gaussianity of curvature
perturbations is characterized by two dimensionless amplitudes. One of these
amplitudes can be expressed in terms of the usual inflationary observables --
the scalar power, the tensor power, and the tensor index. This consistency
relation provides an observational test for the single scalar inflation.Comment: 6 page
Thermal energy consumption at drying saw-timber in periodic convection drying chambers
Calculation of thermal energy consumption is executed at drying saw-timber in periodic convection chambers. It is established, that with the mode rigidity increase the total drying heat consumption decreases. It is recommended to apply more rigid modes to reduce the thermal energy consumption
CMB Anisotropies from Outflows in Lyman Break Galaxies
Thomson scattering of the Cosmic Microwave Background (CMB) on moving
electrons in the outflows of Lyman Break Galaxies (LBGs) at redshifts 2-8
contributes to the small-scale CMB anisotropies. The net effect produced by
each outflow depends on its level of deviation from spherical symmetry, caused
either by an anisotropic energy injection from the nuclear starburst or quasar
activity, or by an inhomogeneous intergalactic environment. We find that for
plausible outflow parameters consistent with spectroscopic observations of
LBGs, the induced CMB anisotropies on arcminute scales reach up to K, comparable to the level produced during the epoch of reionization.Comment: 5 pages, 2 figures; to be submitted to MNRA
Effect of cyclosporin and tacrolimus on kidney function in liver recipients
The objective of the study was to evaluate the dynamics of renal function, depending on the use of various calcineurin inhibitors in the long-term postoperative period in liver recipients in real clinical practic
Gender and age differences of compliance in liver transplant recipients
The aim of the paper was to evaluate the compliance in patients who have undergone orthotopic liver transplantation (OLT). A voluntary anonymous survey was conducted among liver transplant recipients. The control group included patients with chronic non-infectious diseases requiring persistent treatment. Liver transplant patients have higher levels of general, behavioral and emotional compliance compared to patients with chronic diseases. Neither gender nor age differences were identified in any types of complianc
Limits on non-Gaussianities from WMAP data
We develop a method to constrain the level of non-Gaussianity of density
perturbations when the 3-point function is of the "equilateral" type.
Departures from Gaussianity of this form are produced by single field models
such as ghost or DBI inflation and in general by the presence of higher order
derivative operators in the effective Lagrangian of the inflaton. We show that
the induced shape of the 3-point function can be very well approximated by a
factorizable form, making the analysis practical. We also show that, unless one
has a full sky map with uniform noise, in order to saturate the Cramer-Rao
bound for the error on the amplitude of the 3-point function, the estimator
must contain a piece that is linear in the data. We apply our technique to the
WMAP data obtaining a constraint on the amplitude f_NL^equil of "equilateral"
non-Gaussianity: -366 < f_NL^equil < 238 at 95% C.L. We also apply our
technique to constrain the so-called "local" shape, which is predicted for
example by the curvaton and variable decay width models. We show that the
inclusion of the linear piece in the estimator improves the constraint over
those obtained by the WMAP team, to -27 < f_NL^local < 121 at 95% C.L.Comment: 20 pages, 12 eps figure
- …