799 research outputs found
Fast, exact CMB power spectrum estimation for a certain class of observational strategies
We describe a class of observational strategies for probing the anisotropies
in the cosmic microwave background (CMB) where the instrument scans on rings
which can be combined into an n-torus, the {\em ring torus}. This class has the
remarkable property that it allows exact maximum likelihood power spectrum
estimation in of order operations (if the size of the data set is )
under circumstances which would previously have made this analysis intractable:
correlated receiver noise, arbitrary asymmetric beam shapes and far side lobes,
non-uniform distribution of integration time on the sky and partial sky
coverage. This ease of computation gives us an important theoretical tool for
understanding the impact of instrumental effects on CMB observables and hence
for the design and analysis of the CMB observations of the future. There are
members of this class which closely approximate the MAP and Planck satellite
missions. We present a numerical example where we apply our ring torus methods
to a simulated data set from a CMB mission covering a 20 degree patch on the
sky to compute the maximum likelihood estimate of the power spectrum
with unprecedented efficiency.Comment: RevTeX, 14 pages, 5 figures. A full resolution version of Figure 1
and additional materials are at http://feynman.princeton.edu/~bwandelt/RT
Conditional KCa3.1-transgene induction in murine skin produces pruritic eczematous dermatitis with severe epidermal hyperplasia and hyperkeratosis
Ion channels have recently attracted attention as potential mediators of skin disease. Here, we explored the consequences of genetically encoded induction of the cell volume-regulating Ca2+-activated KCa3.1 channel (Kcnn4) for murine epidermal homeostasis. Doxycycline-treated mice harboring the KCa3.1+-transgene under the control of the reverse tetracycline-sensitive transactivator (rtTA) showed 800-fold channel overexpression above basal levels in the skin and solid KCa3.1-currents in keratinocytes. This overexpression resulted in epidermal spongiosis, progressive epidermal hyperplasia and hyperkeratosis, itch and ulcers. The condition was accompanied by production of the pro-proliferative and pro-inflammatory cytokines, IL-ß1 (60-fold), IL-6 (33-fold), and TNFa (26-fold) in the skin. Treatment of mice with the KCa3.1-selective blocker, Senicapoc, significantly suppressed spongiosis and hyperplasia, as well as induction of IL-ß1 (-88%) and IL-6 (-90%). In conclusion, KCa3.1-induction in the epidermis caused expression of pro-proliferative cytokines leading to spongiosis, hyperplasia and hyperkeratosis. This skin condition resembles pathological features of eczematous dermatitis and identifies KCa3.1 as a regulator of epidermal homeostasis and spongiosis, and as a potential therapeutic target
Estimating the age of domestic fowl (Gallus gallus domesticus L. 1758) cockerels through spur development
Determining the age of bird remains after the cessation of growth is challenging due to the absence of techniques such as tooth eruption and wear available for mammals. Without these techniques, it is difficult to reconstruct hunting strategies, husbandry regimes, and wider human–animal relationships. This paper presents a new method, developed from a collection (n = 71) of known-age specimens of domestic fowl (Gallus gallus domesticus L. 1758), for assessing age based on the fusion and size of the tarsometatarsal spur. Using this method, we reconstruct the demographics of domestic fowl from Iron Age to Early Modern sites in Britain to reveal the changing dynamics of human–domestic fowl relationships. We highlight the advanced age that cockerels often attained in their early history and how their life expectancies have subsequently declined
Solar Wind Turbulence and the Role of Ion Instabilities
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On recrystallization in metal matrix composites
The plane strain deformation of model continuous fibre composites such as Cu-W provides a vehicle for the study of the macroscopic effects of second phase particles on the strain distribution in the matrix and its possible effects on subsequent recrystallization behaviour. By using metallographic studies based both on optical gridding methods and low temperature recrystallization, the pattern of flow enforced by the fibres can be quantified and related to the spatial distribution of recrystallization events
The Relation Between the Surface Brightness and the Diameter for Galactic Supernova Remnants
In this work, we have constructed a relation between the surface brightness
() and diameter (D) of Galactic C- and S-type supernova remnants
(SNRs). In order to calibrate the -D dependence, we have carefully
examined some intrinsic (e.g. explosion energy) and extrinsic (e.g. density of
the ambient medium) properties of the remnants and, taking into account also
the distance values given in the literature, we have adopted distances for some
of the SNRs which have relatively more reliable distance values. These
calibrator SNRs are all C- and S-type SNRs, i.e. F-type SNRs (and S-type SNR
Cas A which has an exceptionally high surface brightness) are excluded. The
Sigma-D relation has 2 slopes with a turning point at D=36.5 pc: (at 1
GHz)=8.4 D
WmHzster (for
WmHzster and D36.5 pc) and (at 1
GHz)=2.7 10 D
WmHzster (for
WmHzster and D36.5 pc). We discussed the theoretical
basis for the -D dependence and particularly the reasons for the change
in slope of the relation were stated. Added to this, we have shown the
dependence between the radio luminosity and the diameter which seems to have a
slope close to zero up to about D=36.5 pc. We have also adopted distance and
diameter values for all of the observed Galactic SNRs by examining all the
available distance values presented in the literature together with the
distances found from our -D relation.Comment: 45 pages, 2 figures, accepted for publication in Astronomical and
Astrophysical Transaction
Detector Description and Performance for the First Coincidence Observations between LIGO and GEO
For 17 days in August and September 2002, the LIGO and GEO interferometer
gravitational wave detectors were operated in coincidence to produce their
first data for scientific analysis. Although the detectors were still far from
their design sensitivity levels, the data can be used to place better upper
limits on the flux of gravitational waves incident on the earth than previous
direct measurements. This paper describes the instruments and the data in some
detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial
change
Quantum walks: a comprehensive review
Quantum walks, the quantum mechanical counterpart of classical random walks,
is an advanced tool for building quantum algorithms that has been recently
shown to constitute a universal model of quantum computation. Quantum walks is
now a solid field of research of quantum computation full of exciting open
problems for physicists, computer scientists, mathematicians and engineers.
In this paper we review theoretical advances on the foundations of both
discrete- and continuous-time quantum walks, together with the role that
randomness plays in quantum walks, the connections between the mathematical
models of coined discrete quantum walks and continuous quantum walks, the
quantumness of quantum walks, a summary of papers published on discrete quantum
walks and entanglement as well as a succinct review of experimental proposals
and realizations of discrete-time quantum walks. Furthermore, we have reviewed
several algorithms based on both discrete- and continuous-time quantum walks as
well as a most important result: the computational universality of both
continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing
Journa
Spectroscopic examinations of hydro- and glaciovolcanic basaltic tuffs: Modes of alteration and relevance for Mars
Hydro- and glaciovolcanism are processes that have taken place on both Earth and Mars. The amount of materials produced by these processes that are present in the martian surface layer is unknown, but may be substantial. We have used Mars rover analogue analysis techniques to examine altered tuff samples collected from multiple hydrovolcanic features, tuff rings and tuff cones, in the American west and from glaciovolcanic hyaloclastite ridges in Washington state and in Iceland. Analysis methods include VNIR-SWIR reflectance, MWIR thermal emissivity, thin section petrography, XRD, XRF, and Mössbauer spectroscopy. We distinguish three main types of tuff that differ prominently in petrography and VNIR-SWIR reflectance: minimally altered sideromelane tuff, gray to brown colored smectite-bearing tuff, and highly palagonitized tuff. Differences are also observed between the tuffs associated with hydrovolcanic tuff rings and tuff cones and those forming glaciovolcanic hyaloclastite ridges. For the locations sampled, hydrovolcanic palagonite tuffs are more smectite and zeolite rich while the palagonitized hyaloclastites from the sampled sites are largely devoid of zeolites and relatively lacking in smectites as well. The gray to brown colored tuffs are only observed in the hydrovolcanic deposits and appear to represent a distinct alteration pathway, with formation of smectites without associated palagonite formation. This is attributed to lower temperatures and possibly longer time scale alteration. Altered hydro- or glaciovolcanic materials might be recognized on the surface of Mars with rover-based instrumentation based on the results of this study
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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