2,458 research outputs found
1+3 Covariant Cosmic Microwave Background anisotropies II: The almost - Friedmann Lemaitre model
This is the second of a series of papers extending the 1+3 covariant and
gauge invariant treatment of kinetic theory to an examination of Cosmic
Microwave Background temperature anisotropies arising from inhomogeneities in
the early universe. The first paper dealt with algebraic issues.
Here we derive the mode form of the integrated Boltzmann equations, first,
giving a covariant version of the standard derivation using the mode recursion
relations, second, demonstrating the link to the multipole divergence equations
and finally various analytic ways of solving the resulting equations are
discussed.
A general integral form of solution is obtained for the equations with
Thomson scattering. The covariant Friedmann-Lemaitre multipole form of the
transport equations are found using the covariant and gauge-invariant
generalization of the Peebles and Yu expansion in Thompson scattering time. The
dispersion relations and damping scale are then obtained from the covariant
approach. The equations are integrated to give the covariant and
gauge-invariant equivalent of the canonical scalar sourced anisotropies.
We carry out a simple treatment of the matter dominated free-streaming
projection, slow decoupling, and tight-coupling cases, with the aim both giving
a unified transparent derivation of this range of results and clarifying the
connection between the more usual approaches (for example that of Hu and
Sugiyama) and the treatment for scalar perturbations (for example the treatment
of Challinor and Lasenby).Comment: To appear in Annals of Physic
Small but crucial : the novel small heat shock protein Hsp21 mediates stress adaptation and virulence in Candida albicans
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Mites Parasitic on Australasian and African Spiders Found in the Pet Trade; a Redescription of Ljunghia pulleinei Womersley
Parasitic mites associated with spiders are spreading world-wide through the trade in tarantulas and other pet species.
Ljunghia pulleinei Womersley, a mesostigmatic laelapid mite originally found in association with the mygalomorph spider
Selenocosmia stirlingi Hogg (Theraphosidae) in Australia, is redescribed and illustrated on the basis of specimens from the
African theraphosid spider Pterinochilus chordatus (Gersta¨cker) kept in captivity in the British Isles (Wales). The mite is known
from older original descriptions of Womersley in 1956; the subsequent redescription of Domrow in 1975 seems to be
questionable in conspecificity of treated specimens with the type material. Some inconsistencies in both descriptions are
recognised here as intraspecific variability of the studied specimens. The genus Arachnyssus Ma, with species A. guangxiensis
(type) and A. huwenae, is not considered to be a valid genus, and is included in synonymy with Ljunghia Oudemans. A new
key to world species of the genus Ljunghia is provided
Gauge-ready formulation of the cosmological kinetic theory in generalized gravity theories
We present cosmological perturbations of kinetic components based on
relativistic Boltzmann equations in the context of generalized gravity
theories. Our general theory considers an arbitrary number of scalar fields
generally coupled with the gravity, an arbitrary number of mutually interacting
hydrodynamic fluids, and components described by the relativistic Boltzmann
equations like massive/massless collisionless particles and the photon with the
accompanying polarizations. We also include direct interactions among fluids
and fields. The background FLRW model includes the general spatial curvature
and the cosmological constant. We consider three different types of
perturbations, and all the scalar-type perturbation equations are arranged in a
gauge-ready form so that one can implement easily the convenient gauge
conditions depending on the situation. In the numerical calculation of the
Boltzmann equations we have implemented four different gauge conditions in a
gauge-ready manner where two of them are new. By comparing solutions solved
separately in different gauge conditions we can naturally check the numerical
accuracy.Comment: 26 pages, 9 figures, revised thoroughly, to appear in Phys. Rev.
Evaluation of a synthetic single-crystal diamond detector for relative dosimetry on the Leksell Gamma Knife Perfexion radiosurgery system
Purpose: To evaluate the new commercial PTW-60019 synthetic single-crystal microDiamond detector (PTW, Freiburg, Germany) for relative dosimetry measurements on a clinical Leksell Gamma Knife Perfexion radiosurgery system. Methods: Detector output ratios (DORs) for 4 and 8 mm beams were measured using a micro- Diamond (PTW-60019), a stereotactic unshielded diode [IBA stereotactic field detector (SFD)], a shielded diode (IBA photon field detector), and GafChromic EBT3 films. Both parallel and transversal acquisition directions were considered for PTW-60019 measurements. Measured DORs were compared to the new output factor reference values for Gamma Knife Perfexion (0.814 and 0.900 for 4 and 8 mm, respectively). Profiles in the three directions were also measured for the 4 mm beam to evaluate full width at half maximum (FWHM) and penumbra and to compare them with the corresponding Leksell GammaPlan profiles. Results: FWHM and penumbra for PTW-60019 differed from the calculated values by less than 0.2 and 0.3 mm, for the parallel and transversal acquisitions, respectively. GafChromic films showed FWHM and penumbra within 0.1 mm. The output ratio obtained with the PTW-60019 for the 4 mm field was 1.6% greater in transverse direction compared to the nominal value. Comparable differences up to 0.8% and 1.0% for, respectively, GafChromic films and SFD were found. Conclusions: The microDiamond PTW-60019 is a suitable detector for commissioning and routine use of Gamma Knife with good agreement of both DORs and profiles in the three directions
A search for the decay modes B+/- to h+/- tau l
We present a search for the lepton flavor violating decay modes B+/- to h+/-
tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472
million BBbar pairs. The search uses events where one B meson is fully
reconstructed in one of several hadronic final states. Using the momenta of the
reconstructed B, h, and l candidates, we are able to fully determine the tau
four-momentum. The resulting tau candidate mass is our main discriminant
against combinatorial background. We see no evidence for B+/- to h+/- tau l
decays and set a 90% confidence level upper limit on each branching fraction at
the level of a few times 10^-5.Comment: 15 pages, 7 figures, submitted to Phys. Rev.
Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo
We use data from the second science run of the LIGO gravitational-wave
detectors to search for the gravitational waves from primordial black hole
(PBH) binary coalescence with component masses in the range 0.2--.
The analysis requires a signal to be found in the data from both LIGO
observatories, according to a set of coincidence criteria. No inspiral signals
were found. Assuming a spherical halo with core radius 5 kpc extending to 50
kpc containing non-spinning black holes with masses in the range 0.2--, we place an observational upper limit on the rate of PBH coalescence
of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
Macrocheles species (Acari: Macrochelidae) associated with human corpses in Europe
The biology of macrochelid mites might offer new venues for the interpretation of the environmental conditions surrounding human death and decomposition. Three human corpses, one from Sweden and two from Spain, have been analysed for the occurrence of Macrochelidae species.
Macrocheles muscaedomesticae females were associated with a corpse that was found in a popular beach area of southeast Spain. Their arrival coincides with the occurrence of one of their major carrier species, the filth fly Fannia scalaris, the activity of which peaks during mid-summer. M. glaber specimens were collected from a corpse in a shallow grave in a forest in Sweden at the end of summer, concurrent with the arrival of beetles attracted by odours from the corpse. M. perglaber adults were sampled from a corpse found indoors in the rural surroundings of Granada city, Spain. The phoretic behaviour of this species is similar to that of M. glaber, but being more specific to Scarabaeidae and Geotrupidae dung beetles, most of which favour human faeces.
M. muscaedomesticae is known from urban and rural areas and poultry farms; M. glaber from outdoors, particularly the countryside; while M. perglaber from outdoor, rural, and remote, potentially mountainous locations.
M. muscaedomesticae and M. perglaber are reported for the first time from the Iberian Peninsula. This is the first record of M. perglaber from human remains
Evidence for an excess of B -> D(*) Tau Nu decays
Based on the full BaBar data sample, we report improved measurements of the
ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or
mu. These ratios are sensitive to new physics contributions in the form of a
charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) =
0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0
sigma and 2.7 sigma, respectively. Taken together, our results disagree with
these expectations at the 3.4 sigma level. This excess cannot be explained by a
charged Higgs boson in the type II two-Higgs-doublet model. We also report the
observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the
format of Figure 2 and included the effect of the change of the Tau
polarization due to the charged Higg
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