633 research outputs found
Regular solutions to higher order curvature Einstein--Yang-Mills systems in higher dimensions
We study regular, static, spherically symmetric solutions of Yang-Mills
theories employing higher order invariants of the field strength coupled to
gravity in dimensions. We consider models with only two such invariants
characterised by integers and . These models depend on one dimensionless
parameter leading to one-parameter families of regular solutions,
obtainable by numerical solution of the corresponding boundary value problem.
Much emphasis is put on an analytical understanding of the numerical results.Comment: 34 pages, 12 figure
H7N9 influenza A virus transmission in a multispecies barnyard model
Influenza A viruses are a diverse group of pathogens that have been responsible for millions of human and avian deaths throughout history. Here, we illustrate the transmission potential of H7N9 influenza A virus between Coturnix quail (Coturnix sp.), domestic ducks (Anas platyrhynchos domesticus), chickens (Gallus gallus domesticus), and house sparrows (Passer domesticus) co-housed in an artificial barnyard setting. In each of four replicates, individuals from a single species were infected with the virus. Quail shed virus orally and were a source of infection for both chickens and ducks. Infected chickens transmitted the virus to quail but not to ducks or house sparrows. Infected ducks transmitted to chickens, resulting in seroconversion without viral shedding. House sparrows did not shed virus sufficiently to transmit to other species. These results demonstrate that onward transmission varies by index species, and that gallinaceous birds are more likely to maintain H7N9 than ducks or passerines
Oncomodulin, an EF-hand Ca2+ buffer, is critical for maintaining cochlear function in mice
UNLABELLED: Oncomodulin (Ocm), a member of the parvalbumin family of calcium binding proteins, is expressed predominantly by cochlear outer hair cells in subcellular regions associated with either mechanoelectric transduction or electromotility. Targeted deletion of Ocm caused progressive cochlear dysfunction. Although sound-evoked responses are normal at 1 month, by 4 months, mutants show only minimal distortion product otoacoustic emissions and 70-80 dB threshold shifts in auditory brainstem responses. Thus, Ocm is not critical for cochlear development but does play an essential role for cochlear function in the adult mouse.
SIGNIFICANCE STATEMENT: Numerous proteins act as buffers, sensors, or pumps to control calcium levels in cochlear hair cells. In the inner ear, EF-hand calcium buffers may play a significant role in hair cell function but have been very difficult to study. Unlike other reports of genetic disruption of EF-hand calcium buffers, deletion of oncomodulin (Ocm), which is predominately found in outer hair cells, leads to a progressive hearing loss after 1 month, suggesting that Ocm critically protects hearing in the mature ear
Black Hole Critical Phenomena Without Black Holes
Studying the threshold of black hole formation via numerical evolution has
led to the discovery of fascinating nonlinear phenomena. Power-law mass
scaling, aspects of universality, and self-similarity have now been found for a
large variety of models. However, questions remain. Here I briefly review
critical phenomena, discuss some recent results, and describe a model which
demonstrates similar phenomena without gravity.Comment: 13 pages, 6 figures; Submission for the proceedings of ICGC 2000 in
the journal Preman
Chiral models in dilaton-Maxwell gravity
We study symmetry properties of the Einstein-Maxwell theory nonminimaly
coupled to the dilaton field. We consider a static case with pure electric
(magnetic) Maxwell field and show that the resulting system becomes a nonlinear
sigma-model wich possesses a chiral representation. We construct the
corresponding chiral matrix and establish a representation which is related to
the pair of Ernst-like potentials. These potentials are used for separation of
the symmetry group into the gauge and nongauge (charging) sectors. New
variables, which linearize the action of charging symmetries, are also
established; a solution generation technique based on the use of charging
symmetries is formulated. This technique is used for generation of the
elecricaly (magneticaly) charged dilatonic fields from the static General
Relativity ones.Comment: 9 pages in LaTex; published in Gen. Rel. Grav. 32 (2000) pp 1389-139
Non-asymptotically flat, non-AdS dilaton black holes
We show that previously known non-asymptotically flat static black hole
solutions of Einstein-Maxwell-dilaton theory may be obtained as near-horizon
limits of asymptotically flat black holes. Specializing to the case of the
dilaton coupling constant , we generate from the
non-asymptotically flat magnetostatic or electrostatic black holes two classes
of rotating dyonic black hole solutions. The rotating dyonic black holes of the
``magnetic'' class are dimensional reductions of the five-dimensional
Myers-Perry black holes relative to one of the azimuthal angles, while those of
the ``electric'' class are twisted dimensional reductions of rotating dyonic
Rasheed black strings. We compute the quasi-local mass and angular momentum of
our rotating dyonic black holes, and show that they satisfy the first law of
black hole thermodynamics, as well as a generalized Smarr formula. We also
discuss the construction of non-asymptotically flat multi-extreme black hole
configurations.Comment: Minor corrections. 2 references added. To appear in Physical Review
Gravitating Magnetic Monopole in the Global Monopole Spacetime
In this paper we study the regular self-gravitating 't Hooft-Polyakov
magnetic monopole in a global monopole spacetime. We show that for the large
distance, the structure of the manifold corresponds to the
Reissner-Nordstr\"{o}m spacetime with a solid angle deficit factor. Although we
analyze static and spherically symmetric solutions, it is not possible to solve
analytically the system of coupled differential equations and only numerical
evaluations can provide detailed information about the behavior of this system
at the neighborhood of the defect's core. So, for this reason we solve
numerically the set of differential equations for the metric tensor and for the
matter fields for different values of the Higgs field vacuum expectation value,
, and the self-coupling constant, .Comment: 26 pages, 6 figures, LaTex forma
Potential Use for Serosurveillance of Feral Swine to Map Risk for Anthrax Exposure, Texas, USA
Anthrax is a disease of concern in many mammals, including humans. Management primarily consists of prevention through vaccination and tracking clinical-level observations because environmental isolation is laborious and bacterial distribution across large geographic areas diffi cult to confi rm. Feral swine (Sus scrofa) are an invasive species with an extensive range in the southern United States that rarely succumbs to anthrax. We present evidence that feral swine might serve as biosentinels based on comparative seroprevalence in swine from historically defi ned anthrax-endemic and non–anthraxendemic regions of Texas. Overall seropositivity was 43.7% (n = 478), and logistic regression revealed county endemicity status, age-class, sex, latitude, and longitude were informative for predicting antibody status. However, of these covariates, only latitude was statistically signifi cant (β = –0.153, p = 0.047). These results suggests anthrax exposure in swine, when paired with continuous location data, could serve as a proxy for bacterial presence in specifi c areas
Inverse dualisation and non-local dualities between Einstein gravity and supergravities
We investigate non-local dualities between suitably compactified
higher-dimensional Einstein gravity and supergravities which can be revealed if
one reinterprets the dualised Kaluza-Klein two-forms in as antisymmetric
forms belonging to supergravities. We find several examples of such a
correspondence including one between the six-dimensional Einstein gravity and
the four-dimensional Einstein-Maxwell-dilaton-axion theory (truncated N=4
supergravity), and others between the compactified eleven and ten-dimensional
supergravities and the eight or ten-dimensional pure gravity. The Killing
spinor equation of the D=11 supergravity is shown to be equivalent to the
geometric Killing spinor equation in the dual gravity. We give several examples
of using new dualities for solution generation and demonstrate how -branes
can be interpreted as non-local duals of pure gravity solutions. New
supersymmetric solutions are presented including -brane with two
rotation parameters.Comment: 32 pages, Late
- …