2,413 research outputs found
Size Gap for Zero Temperature Black Holes in Semiclassical Gravity
We show that a gap exists in the allowed sizes of all zero temperature static
spherically symmetric black holes in semiclassical gravity when only
conformally invariant fields are present. The result holds for both charged and
uncharged black holes. By size we mean the proper area of the event horizon.
The range of sizes that do not occur depends on the numbers and types of
quantized fields that are present. We also derive some general properties that
both zero and nonzero temperature black holes have in all classical and
semiclassical metric theories of gravity.Comment: 4 pages, ReVTeX, no figure
Translation products of RNA from Indian peanut clump virus
When RNA from particles of Indian peanut clump virus (IPCV) was translated using messenger-dependent reticulocyte lysate the largest product had a mol. wt. of about 195000 and the other main products had mol. wt. of 143000 and 24500. The 24500 mol. wt. polypeptide co-migrated with IPCV coat protein and was the only product that reacted with antiserum to IPCV particles. Translation of separated RNA species showed that the 195000 mol. wt. and 143000 mol. wt., as well as some smaller less abundant products, arose from translation of RNA-1 (mol. wt. 1.9 x 106) whereas RNA-2 (mol. wt. 1.6 x 106) was translated to give only the 24500 mol. wt. product Translation ofRNA ofmol, wt. 0.5 x 106 to 0.9 × 106 gave a 50000 mol. wt. product that was present and sometimes prominent in translation products of unfractionated RNA. A product of about 20000 mol. wt. was made by translation of RNA of about 0.2 x 106 tool. wt. IPCV resembles the viruses with bipartite genomes whose larger RNA species is translated into large polypeptides and whose coat protein gene is on the smaller RNA species. The other translation products may be those of subgenomic messenger, or of satellite, RNA species
Mechanism of Generation of Black Hole Entropy in Sakharov's Induced Gravity
The mechanism of generation of the Bekenstein-Hawking entropy of a
black hole in the Sakharov's induced gravity is proposed. It is suggested that
the "physical" degrees of freedom, which explain the entropy , form
only a finite subset of the standard Rindler-like modes defined outside the
black hole horizon. The entropy of the Rindler modes, or entanglement
entropy, is always ultraviolet divergent, while the entropy of the "physical"
modes is finite and it coincides in the induced gravity with . The two
entropies and differ by a surface integral Q interpreted as a
Noether charge of non-minimally coupled scalar constituents of the model. We
demonstrate that energy E and Hamiltonian H of the fields localized in a part
of space-time, restricted by the Killing horizon , differ by the
quantity , where is the temperature of a black hole. The first law
of the black hole thermodynamics enables one to relate the probability
distribution of fluctuations of the black hole mass, caused by the quantum
fluctuations of the fields, to the probability distribution of "physical" modes
over energy E. The latter turns out to be different from the distribution of
the Rindler modes. We show that the probability distribution of the "physical"
degrees of freedom has a sharp peak at E=0 with the width proportional to the
Planck mass. The logarithm of number of "physical" states at the peak coincides
exactly with the black hole entropy . It enables us to argue that the
energy distribution of the "physical" modes and distribution of the black hole
mass are equivalent in the induced gravity. Finally it is shown that the
Noether charge Q is related to the entropy of the low frequency modes
propagating in the vicinity of the bifurcation surface of the horizon.Comment: 28 pages, Latex fil
Angular Forces Around Transition Metals in Biomolecules
Quantum-mechanical analysis based on an exact sum rule is used to extract an
semiclassical angle-dependent energy function for transition metal ions in
biomolecules. The angular dependence is simple but different from existing
classical potentials. Comparison of predicted energies with a
computer-generated database shows that the semiclassical energy function is
remarkably accurate, and that its angular dependence is optimal.Comment: Tex file plus 4 postscript figure
No Scalar Hair Theorem for a Charged Spherical Black Hole
This paper consolidates noscalar hair theorem for a charged spherically
symmetric black hole in four dimension in general relativity as well as in all
scalar tensor theories, both minimally and nonminimally coupled, when the
effective Newtonian constant of gravity is positive. However, there is an
exception when the matter field itself is coupled to the scalar field, such as
in dilaton gravity.Comment: 13 pages, Latex format, some minor corrections are made, accepted for
publication in Physical Review
In Vitro Evaluation of the Toxicological Profile and Oxidative Stress of Relevant Diet-Related Advanced Glycation End Products and Related 1,2-Dicarbonyls
During food processing and storage, and in tissues and fluids under physiological conditions, the Maillard reaction occurs. During this reaction, reactive 1,2-dicarbonyl compounds arise as intermediates that undergo further reactions to form advanced glycation end products (AGEs). Diet is the primary source of exogenous AGEs. Endogenously formed AGEs have been proposed as a risk factor in the pathogenesis of diet-related diseases such as diabetes, insulin resistance, cardiovascular diseases, or chronic disease. AGEs may differently contribute to the diet-related exacerbation of oxidative stress, inflammation, and protein modifications. Here, to understand the contribution of each compound, we tested individually, for the first time, the effect of five 1,2-dicarbonyl compounds 3-deoxyglucosone (3-DG), 3-deoxygalactosone (3-DGal), 3,4-dideoxyglucosone-3-ene (3,4-DGE), glyoxal (GO), and methylglyoxal (MGO) and four different glycated amino acids N-ε-(carboxyethyl)lysine (CEL), N-ε-(carboxymethyl)lysine (CML), methylglyoxal-derived hydroimidazolone-1 (MG-H1), and pyrraline (Pyrr) in a cell line of human keratinocytes (HaCaT). We found that most of the glycated amino acids, i.e., CEL, CML, and MG-H1, did not show any cytotoxicity. At the same time, 1,2-dicarbonyl compounds 3-DGal, 3,4-DGE, GO, and MGO increased the production of reactive oxygen species and induced cell death. MGO induced cell death by apoptosis, whereas 3-DGal and 3,4-DGE induced nuclear translocation of the proinflammatory NF-κB transcription pathway, and the activation of the pyroptosis-related NLRP3 inflammasome cascade. Overall, these results demonstrate the higher toxic impact of 1,2-dicarbonyl compounds on mucosal epithelial cells when compared to glycated amino acids and the selective activation of intracellular signaling pathways involved in the crosstalk mechanisms linking oxidative stress to excessive inflammation
Highly damped quasinormal modes of Kerr black holes
Motivated by recent suggestions that highly damped black hole quasinormal
modes (QNM's) may provide a link between classical general relativity and
quantum gravity, we present an extensive computation of highly damped QNM's of
Kerr black holes. We do not limit our attention to gravitational modes, thus
filling some gaps in the existing literature. The frequency of gravitational
modes with l=m=2 tends to \omega_R=2 \Omega, \Omega being the angular velocity
of the black hole horizon. If Hod's conjecture is valid, this asymptotic
behaviour is related to reversible black hole transformations. Other highly
damped modes with m>0 that we computed do not show a similar behaviour. The
real part of modes with l=2 and m<0 seems to asymptotically approach a constant
value \omega_R\simeq -m\varpi, \varpi\simeq 0.12 being (almost) independent of
a. For any perturbing field, trajectories in the complex plane of QNM's with
m=0 show a spiralling behaviour, similar to the one observed for
Reissner-Nordstrom (RN) black holes. Finally, for any perturbing field, the
asymptotic separation in the imaginary part of consecutive modes with m>0 is
given by 2\pi T_H (T_H being the black hole temperature). We conjecture that
for all values of l and m>0 there is an infinity of modes tending to the
critical frequency for superradiance (\omega_R=m) in the extremal limit.
Finally, we study in some detail modes branching off the so--called
``algebraically special frequency'' of Schwarzschild black holes. For the first
time we find numerically that QNM multiplets emerge from the algebraically
special Schwarzschild modes, confirming a recent speculation.Comment: 19 pages, 11 figures. Minor typos corrected. Updated references to
take into account some recent development
VerdictDB: Universalizing Approximate Query Processing
Despite 25 years of research in academia, approximate query processing (AQP)
has had little industrial adoption. One of the major causes of this slow
adoption is the reluctance of traditional vendors to make radical changes to
their legacy codebases, and the preoccupation of newer vendors (e.g.,
SQL-on-Hadoop products) with implementing standard features. Additionally, the
few AQP engines that are available are each tied to a specific platform and
require users to completely abandon their existing databases---an unrealistic
expectation given the infancy of the AQP technology. Therefore, we argue that a
universal solution is needed: a database-agnostic approximation engine that
will widen the reach of this emerging technology across various platforms.
Our proposal, called VerdictDB, uses a middleware architecture that requires
no changes to the backend database, and thus, can work with all off-the-shelf
engines. Operating at the driver-level, VerdictDB intercepts analytical queries
issued to the database and rewrites them into another query that, if executed
by any standard relational engine, will yield sufficient information for
computing an approximate answer. VerdictDB uses the returned result set to
compute an approximate answer and error estimates, which are then passed on to
the user or application. However, lack of access to the query execution layer
introduces significant challenges in terms of generality, correctness, and
efficiency. This paper shows how VerdictDB overcomes these challenges and
delivers up to 171 speedup (18.45 on average) for a variety of
existing engines, such as Impala, Spark SQL, and Amazon Redshift, while
incurring less than 2.6% relative error. VerdictDB is open-sourced under Apache
License.Comment: Extended technical report of the paper that appeared in Proceedings
of the 2018 International Conference on Management of Data, pp. 1461-1476.
ACM, 201
Area Spectrum of Kerr and extremal Kerr Black Holes from Quasinormal Modes
Motivated by the recent interest in quantization of black hole area spectrum,
we consider the area spectrum of Kerr and extremal Kerr black holes. Based on
the proposal by Bekenstein and others that the black hole area spectrum is
discrete and equally spaced, we implement Kunstatter's method to derive the
area spectrum for the Kerr and extremal Kerr black holes. The real part of the
quasinormal frequencies of Kerr black hole used for this computation is of the
form where is the angular velocity of the black hole
horizon. The resulting spectrum is discrete but not as expected uniformly
spaced. Thus, we infer that the function describing the real part of
quasinormal frequencies of Kerr black hole is not the correct one. This
conclusion is in agreement with the numerical results for the highly damped
quasinormal modes of Kerr black hole recently presented by Berti, Cardoso and
Yoshida. On the contrary, extremal Kerr black hole is shown to have a discrete
area spectrum which in addition is evenly spaced. The area spacing derived in
our analysis for the extremal Kerr black hole area spectrum is not proportional
to . Therefore, it does not give support to Hod's statement that the
area spectrum should be valid for a generic
Kerr-Newman black hole.Comment: 10 pages, no figure, LaTeX; v2: 12 pages, clarifying comments and an
Appendix are added, version to appear in Mod. Phys. Lett.
Late-time evolution of the Yang-Mills field in the spherically symmetric gravitational collapse
We investigate the late-time evolution of the Yang-Mills field in the
self-gravitating backgrounds: Schwarzschild and Reissner-Nordstr\"om
spacetimes. The late-time power-law tails develop in the three asymptotic
regions: the future timelike infinity, the future null infinity and the black
hole horizon. In these two backgrounds, however, the late-time evolution has
quantitative and qualitative differences. In the Schwarzschild black hole
background, the late-time tails of the Yang-Mills field are the same as those
of the neutral massless scalar field with multipole moment l=1. The late-time
evolution is dominated by the spacetime curvature. When the background is the
Reissner-Nordstr\"om black hole, the late-time tails have not only a smaller
power-law exponent, but also an oscillatory factor. The late-time evolution is
dominated by the self-interacting term of the Yang-Mills field. The cause
responsible for the differences is revealed.Comment: Revtex, 14 pages, no figure
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