39 research outputs found
Hilbert Expansion from the Boltzmann equation to relativistic Fluids
We study the local-in-time hydrodynamic limit of the relativistic Boltzmann
equation using a Hilbert expansion. More specifically, we prove the existence
of local solutions to the relativistic Boltzmann equation that are nearby the
local relativistic Maxwellian constructed from a class of solutions to the
relativistic Euler equations that includes a large subclass of near-constant,
non-vacuum fluid states. In particular, for small Knudsen number, these
solutions to the relativistic Boltzmann equation have dynamics that are
effectively captured by corresponding solutions to the relativistic Euler
equations.Comment: 50 page
Asymptotic Stability of the Relativistic Boltzmann Equation for the Soft Potentials
In this paper it is shown that unique solutions to the relativistic Boltzmann
equation exist for all time and decay with any polynomial rate towards their
steady state relativistic Maxwellian provided that the initial data starts out
sufficiently close in . If the initial data are continuous then
so is the corresponding solution. We work in the case of a spatially periodic
box. Conditions on the collision kernel are generic in the sense of
(Dudy{\'n}ski and Ekiel-Je{\.z}ewska, Comm. Math. Phys., 1988); this resolves
the open question of global existence for the soft potentials.Comment: 64 page
THE RATE OF BINARY BLACK HOLE MERGERS INFERRED FROM ADVANCED LIGO OBSERVATIONS SURROUNDING GW150914
A transient gravitational-wave signal, GW150914, was identi
fi
ed in the twin Advanced LIGO detectors on 2015
September 2015 at 09:50:45 UTC. To asse
ss the implications of this discovery,
the detectors remained in operation with
unchanged con
fi
gurations over a period of 39 days around the time of t
he signal. At the detection statistic threshold
corresponding to that observed for GW150914, our search of the 16 days of simultaneous two-detector observational
data is estimated to have a false-alarm rate
(
FAR
)
of
<
́
--
4.9 10 yr
61
, yielding a
p
-value for GW150914 of
<
́
-
210
7
. Parameter estimation follo
w-up on this trigger identi
fi
es its source as a binary black hole
(
BBH
)
merger
with component masses
(
)(
)
=
-
+
-
+
mm
M
,36,29
12
4
5
4
4
at redshift
=
-
+
z
0.09
0.04
0.03
(
median and 90% credible range
)
.
Here, we report on the constraints these observations place on the rate of BBH coalescences. Considering only
GW150914, assuming that all BBHs in the universe have the same masses and spins as this event, imposing a search
FAR threshold of 1 per 100 years, and assuming that the BBH merger rate is constant in the comoving frame, we infer a
90% credible range of merger rates between
–
--
2
53 Gpc yr
31
(
comoving frame
)
. Incorporating all search triggers that
pass a much lower threshold while accounting for the uncerta
inty in the astrophysical origin of each trigger, we estimate
a higher rate, ranging from
–
--
13 600 Gpc yr
31
depending on assumptions about the BBH mass distribution. All
together, our various rate estimat
es fall in the conservative range
–
--
2
600 Gpc yr
31
Effects Of Social Skills Training And Contingency Management On Reciprocal Interaction Of Preschool Children With Behavioral Handicaps
Ototoxicity and tolerance assessment of a TrisEDTA and polyhexamethylene biguanide ear flush formulation in dogs
Clinically healthy mixed breed dogs (n = 20) were used to determine if a Tris (tromethamine)-buffered test solution, Otinide((R)) (Trademark of Dermcare-Vet Pty-Ltd, Australia), containing disodium ethylenediamine tetraacetic acid (EDTA; 1.21 g/L) and polyhexamethylene biguanide (PHMB; 0.22 g/L) caused ototoxicity or vestibular dysfunction. The dogs were randomly assigned to either a control group (group A, n = 10) receiving saline, or a treatment group (group B, n = 10) receiving the test solution. Phase 1 of the study consisted of applying 5.0 mL of saline to both ears of the control group (group A) and 5 mL of test solution to both ears of the test group (group B), for 21 days. A bilateral myringotomy was then performed on each dog under deep sedation. Phase 2 of the study then consisted of applying 2.0 mL of the saline to both ears of the control group (group A) and 2.0 mL of the test solution to both ears of the test group (group B), for 14 days. Throughout the study, dogs were examined for clinical health, and underwent otoscopic, vestibular and auditory examinations. The auditory examinations included brainstem auditory evoked potential (BAEP) threshold and supra-threshold assessments using both click and 8 kHz tone burst stimuli. The absence of vestibular signs and effects on the BAEP attributable to the test solution suggested the test solution could be applied safely to dogs, including those with a damaged tympanic membrane