5,938 research outputs found
Hypervelocity binary stars: smoking gun of massive binary black holes
The hypervelocity stars recently found in the Galactic halo are expelled from
the Galactic center through interactions between binary stars and the central
massive black hole or between single stars and a hypothetical massive binary
black hole. In this paper, we demonstrate that binary stars can be ejected out
of the Galactic center with velocities up to 10^3 km/s, while preserving their
integrity, through interactions with a massive binary black hole. Binary stars
are unlikely to attain such high velocities via scattering by a single massive
black hole or through any other mechanisms. Based on the above theoretical
prediction, we propose a search for binary systems among the hypervelocity
stars. Discovery of hypervelocity binary stars, even one, is a definitive
evidence of the existence of a massive binary black hole in the Galactic
center.Comment: 5 pages, 3 figures, shortened version, ApJL in pres
Sensing Subjective Well-being from Social Media
Subjective Well-being(SWB), which refers to how people experience the quality
of their lives, is of great use to public policy-makers as well as economic,
sociological research, etc. Traditionally, the measurement of SWB relies on
time-consuming and costly self-report questionnaires. Nowadays, people are
motivated to share their experiences and feelings on social media, so we
propose to sense SWB from the vast user generated data on social media. By
utilizing 1785 users' social media data with SWB labels, we train machine
learning models that are able to "sense" individual SWB from users' social
media. Our model, which attains the state-by-art prediction accuracy, can then
be used to identify SWB of large population of social media users in time with
very low cost.Comment: 12 pages, 1 figures, 2 tables, 10th International Conference, AMT
2014, Warsaw, Poland, August 11-14, 2014. Proceeding
Fermion Superfluids of Non-Zero Orbital Angular Momentum near Resonance
We study the pairing of Fermi gases near the scattering resonance of the
partial wave. Using a model potential which reproduces the actual
two-body low energy scattering amplitude, we have obtained an analytic solution
of the gap equation. We show that the ground state of and
superfluid are orbital ferromagnets with pairing wavefunctions and
respectively. For , there is a degeneracy between and
a "cyclic state". Dipole energy will orient the angular momentum axis. The gap
function can be determined by the angular dependence of the momentum
distribution of the fermions.Comment: 4 pages, 1 figur
IMMUNOLOGICAL TOLERANCE IN VITRO: KINETIC STUDIES AT THE CELLULAR LEVEL
When normal mouse spleen, cells in suspension are cultured in vitro in the presence of polymer from S. adelaide flagellin, an immune response can be obtained as measured at the level of single antibody-forming cells. Cultures were stimulated with different doses of antigen, ranging from 0.2 ng to 3 µg/ml of tissue culture fluid and it was found that the peak number of approximately 500 antibody-forming cells per 106 harvested cells by day 4 was antigen dose dependent, 2–20 ng/ml being the optimal concentration. When more than 1 µg/ml of polymer from S. adelaide together with either 20 ng/ml of polymer from S. waycross or with 4 x 106 sheep erythrocytes were placed in the system, unresponsiveness to S. adelaide, but immunity to the other antigens occurred simultaneously. Cells made immunologically tolerant in vitro to S. adelaide H antigens were transferred into syngeneic lethally irradiated recipients and challenged with the same antigen. The adoptive immune capacity in these mice, as measured at the level of the immunologically competent cell was reduced by 80–90% as compared with relevant controls. Attempts to induce low zone tolerance in vitro were without success. To study the kinetics of tolerance induction in vitro, cells were cultured with tolerogenic doses of antigen for various periods of time, washed, and subsequently cultured with immunogenic doses of antigen for 4 days. It was found, that immunological tolerance may be induced to a significant degree in vitro within a period of 15 min. Similar results were obtained when spleen cells were exposed for various lengths of time to tolerogenic doses of antigen but at a temperature of 4°C instead of 37°C. The results are taken as suggestive evidence that the initial step in tolerance induction is related to the direct interaction between the surface of immune competent cells and antigen molecules
General Relativistic Three-Dimensional Multi-Group Neutrino Radiation-Hydrodynamics Simulations of Core-Collapse Supernovae
We report on a set of long-term general-relativistic three-dimensional (3D)
multi-group (energy-dependent) neutrino-radiation hydrodynamics simulations of
core-collapse supernovae. We employ a full 3D two-moment scheme with the local
M1 closure, three neutrino species, and 12 energy groups per species. With
this, we follow the post-core-bounce evolution of the core of a nonrotating
- progenitor in full unconstrained 3D and in octant symmetry for
. We find the development of an asymmetric runaway
explosion in our unconstrained simulation. We test the resolution dependence of
our results and, in agreement with previous work, find that low resolution
artificially aids explosion and leads to an earlier runaway expansion of the
shock. At low resolution, the octant and full 3D dynamics are qualitatively
very similar, but at high resolution, only the full 3D simulation exhibits the
onset of explosion.Comment: Accepted to Ap
Accurate Evolutions of Orbiting Binary Black Holes
We present a detailed analysis of binary black hole evolutions in the last orbit and demonstrate consistent and convergent results for the trajectories of the individual bodies. The gauge choice can significantly affect the overall accuracy of the evolution. It is possible to reconcile certain gauge-dependent discrepancies by examining the convergence limit. We illustrate these results using an initial data set recently evolved by Brügmann et al. [Phys. Rev. Lett. 92, 211101 (2004)]. For our highest resolution and most accurate gauge, we estimate the duration of this data set's last orbit to be approximately 59MADM
Calcitonin gene-related peptide receptor antagonist BIBN 4096 BS for the acute treatment of migraine
Background: Calcitonin gene–related peptide (CGRP) may have a causative role in migraine. We therefore hypothesized that a CGRP-receptor antagonist might be effective in the treatment of migraine attacks.
Methods: In an international, multicenter, double-blind, randomized clinical trial of BIBN 4096 BS, a highly specific and potent nonpeptide CGRP-receptor antagonist, 126 patients with migraine received one of the following: placebo or 0.25, 0.5, 1, 2.5, 5, or 10 mg of BIBN 4096 BS intravenously over a period of 10 minutes. A group-sequential adaptive treatment-assignment design was used to minimize the number of patients exposed.
Results: The 2.5-mg dose was selected, with a response rate of 66 percent, as compared with 27 percent for placebo (P=0.001). The BIBN 4096 BS group as a whole had a response rate of 60 percent. Significant superiority over placebo was also observed with respect to most secondary end points: the pain-free rate at 2 hours; the rate of sustained response over a period of 24 hours; the rate of recurrence of headache; improvement in nausea, photophobia, phonophobia, and functional capacity; and the time to meaningful relief. An effect was apparent after 30 minutes and increased over the next few hours. The overall rate of adverse events was 25 percent after the 2.5-mg dose of the drug and 20 percent for the BIBN 4096 BS group as a whole, as compared with 12 percent for placebo. The most frequent side effect was paresthesia. There were no serious adverse events.
Conclusions: The CGRP antagonist BIBN 4096 BS was effective in treating acute attacks of migraine
Local and global properties of conformally flat initial data for black hole collisions
We study physical properties of conformal initial value data for single and
binary black hole configurations obtained using conformal-imaging and
conformal-puncture methods. We investigate how the total mass M_tot of a
dataset with two black holes depends on the configuration of linear or angular
momentum and separation of the holes. The asymptotic behavior of M_tot with
increasing separation allows us to make conclusions about an unphysical
``junk'' gravitation field introduced in the solutions by the conformal
approaches. We also calculate the spatial distribution of scalar invariants of
the Riemann tensor which determine the gravitational tidal forces. For single
black hole configurations, these are compared to known analytical solutions.
Spatial distribution of the invariants allows us to make certain conclusions
about the local distribution of the additional field in the numerical datasets
Constructive aspects of Riemann's permutation theorem for series
The notions of permutable and weak-permutable convergence of a series
of real numbers are introduced. Classically, these
two notions are equivalent, and, by Riemann's two main theorems on the
convergence of series, a convergent series is permutably convergent if and only
if it is absolutely convergent. Working within Bishop-style constructive
mathematics, we prove that Ishihara's principle \BDN implies that every
permutably convergent series is absolutely convergent. Since there are models
of constructive mathematics in which the Riemann permutation theorem for series
holds but \BDN does not, the best we can hope for as a partial converse to our
first theorem is that the absolute convergence of series with a permutability
property classically equivalent to that of Riemann implies \BDN. We show that
this is the case when the property is weak-permutable convergence
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