397 research outputs found
Einstein's Field Equations for the Interior of a Uniformly Rotating Stationary Axisymmetric Perfect Fluid
We reduce Einstein's field equations for the interior of a uniformly
rotating, axisymmetric perfect fluid to a system of six second order partial
differential equations for the pressure p the energy density and four
dependent variables.Four of these equations do not depend on p and and
the other two determine p and
Black Hole in a Model with Dilaton and Monopole Fields
We present an exact black hole solution in a model having besides gravity a
dilaton and a monopole field. The solution has three free parameters, one of
which can be identified with the monopole charge, and another with the ADM
mass. The metric is asymptotically flat and has two horizons and irremovable
singularity only at . The dilaton field is singular only at . The
dominant and the strong energy condition are satisfied outside and on the
external horizon. According to a formulation of the no hair conjecture the
solution is "hairy". Also the well know GHS-GM solution is obtained from our
solution for certain values of its parameters.Comment: Selected for Honorable Mention in the Gravity Research Foundation
Essay Competition, 2006, 7 page
Family Of Rotating Anisotropic Fluid Solutions which Match to Kerr's Solution
We present a family of exact rotating anisotropic fluid solutions, which
satisfy all energy conditions for certain values of their parameters. The
components of the Ricci tensor the eigenvalues of the tensor
and the energy-momentum tensor of the solutions are
given explicitly. All members of the family have the ring singularity of Kerr's
solution and most of them one or two more singularities. The solutions can be
matched to the solution of Kerr on three closed surfaces, which for proper
values of the parameters of the solutions approximate oblate spheroids. All
matching surfaces are thin shells. For some values of a constant the surface
density in one of them is positive everywhere and in this surface and in its
interior all energy conditions are satisfied.Comment: Published version in IJMP
Rotating Black Hole Solutions with Axion Dilaton and Two Vector Fields and Solutions with Metric and Fields of the Same Form
We present two rotating black hole solutions with axion , dilaton
and two U(1) vector fields. By applying the "Newman-Janis trick" to a metric
with 3 arbitrary parameters we find a rotating metric with 4 such
parameters , and then a solution with this as
metric. Our solution is asymptotically flat and has angular momentum ,
gyromagnetic ratio , two horizons, the singularities of Kerr's solution,
axion and dilaton singular only for . Applying to the solution
we have found the duality transformation we get a new solution, whose
axion, dilaton and vector fields have one more parameter. The metric, each
vector field and the of our solutions and the
solution of : Sen for , Sen for and , Kerr-Newman for and
, Kerr, Ref. 9, STW, GM-GHS, Reissner-Nordstr\"{o}m,Schwarzschild are the
same function of , and two functions and
, of , and two functions, and of , and
respectively, where , , and are constants. It is shown that from
our solutions a number of known solutions can be obtained, which together with
our solutions are listed in an Appendix. Also it is shown that all solutions
which are mentioned in the paper satisfy all energy conditions, and mass
formulae are obtained for them.Comment: 50 page
Finite element inversion of DInSAR data from the Mw 6.3 L’Aquila earthquake, 2009 (Italy)
Fault slip distribution is usually retrieved from geodetic
data assuming that the local crust is an elastic, homogeneous
and isotropic half‐space. In the last decades spatially dense
geodetic data (e.g., DInSAR maps) have highlighted complex
patterns of coseismic deformation that require new modeling
tools, such as numerical methods, able to represent rheological
and geometrical complexities of the Earth’s crust. In this
work, we develop a procedure to perform inversion of geodetic
data based on the finite element method, accounting for
a more realistic description of the local crust. The method
is applied to the 2009 L’Aquila earthquake (Mw 6.3), using
DInSAR images of the coseismic displacement. Results
highlight the non‐negligible influence of the medium structure:
homogeneous and heterogeneous models show discrepancies
up to 20% in the fault slip distribution values.
Furthermore, in the heterogeneous models a new area of slip
appears above the hypocenter. We also perform a resolution
study, showing that the information about fault slip distributions
retrieved from geodetic data should be considered
as averaged on surrounding patches
Contact symmetry of time-dependent Schr\"odinger equation for a two-particle system: symmetry classification of two-body central potentials
Symmetry classification of two-body central potentials in a two-particle
Schr\"{o}dinger equation in terms of contact transformations of the equation
has been investigated. Explicit calculation has shown that they are of the same
four different classes as for the point transformations. Thus in this problem
contact transformations are not essentially different from point
transformations. We have also obtained the detailed algebraic structures of the
corresponding Lie algebras and the functional bases of invariants for the
transformation groups in all the four classes
Dilatonic interpolation between Reissner-Nordstrom and Bertotti-Robinson spacetimes with physical consequences
We give a general class of static, spherically symmetric, non-asymptotically
flat and asymptotically non-(anti) de Sitter black hole solutions in
Einstein-Maxwell-Dilaton (EMD) theory of gravity in 4-dimensions. In this
general study we couple a magnetic Maxwell field with a general dilaton
potential, while double Liouville-type potentials are coupled with the gravity.
We show that the dilatonic parameters play the key role in switching between
the Bertotti-Robinson and Reissner-Nordstr\"om spacetimes. We study the
stability of such black holes under a linear radial perturbation, and in this
sense we find exceptional cases that the EMD black holes are unstable. In
continuation we give a detailed study of the spin-weighted harmonics in
dilatonic Hawking radiation spectrum and compare our results with the
previously known ones. Finally, we investigate the status of resulting naked
singularities of our general solution when probed with quantum test particles.Comment: 27 pages, 4 figures, to appear in CQG
PARP inhibitors in metastatic prostate cancer
Poly-ADP ribose polymerase inhibitors (PARPi) are an emerging therapeutic option for the treatment of prostate cancer. Their primary mechanism of action is via induction of synthetic lethality in cells with underlying deficiencies in homologous recombination repair (HRR). In men with metastatic castrate-resistant prostate cancer (mCRPC) and select HRR pathway alterations, PARPi treatment has been shown to induce objective tumor responses as well as improve progression free and overall survival. Presently, there are two PARPi, olaparib and rucaparib, that are FDA approved in the treatment of mCRPC. Ongoing research is focused on identifying which HRR alterations are best suited to predict response to PARPi so that these therapies can be most effectively utilized in the clinic. While resistance to PARPi remains a concern, combination therapies may represent a mechanism to overcome or delay resistance
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