595 research outputs found
CBR Anisotropy from Primordial Gravitational Waves in Two-Component Inflationary Cosmology
We examine stochastic temperature fluctuations of the cosmic background
radiation (CBR) arising via the Sachs-Wolfe effect from gravitational wave
perturbations produced in the early universe. We consider spatially flat,
perturbed FRW models that begin with an inflationary phase, followed by a mixed
phase containing both radiation and dust. The scale factor during the mixed
phase takes the form , where are
constants. During the mixed phase the universe smoothly transforms from being
radiation to dust dominated. We find analytic expressions for the graviton mode
function during the mixed phase in terms of spheroidal wave functions. This
mode function is used to find an analytic expression for the multipole moments
of the two-point angular correlation function
for the CBR anisotropy. The analytic expression for the multipole
moments is written in terms of two integrals, which are evaluated numerically.
The results are compared to multipoles calculated for models that are {\it
completely} dust dominated at last-scattering. We find that the multipoles
of the CBR temperature perturbations for are
significantly larger for a universe that contains both radiation and dust at
last-scattering. We compare our results with recent, similar numerical work and
find good agreement. The spheroidal wave functions may have applications to
other problems of cosmological interest.Comment: 28 pgs + 6 postscript figures, RevTe
Persistent organic pollutants (POPs) increase rage signaling to promote downstream cardiovascular remodeling
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Background: Antimicrobial resistance (AMR) is a global threat and the antimicrobial stewardship program (ASP) is a globally used tool to combat AMR. There is little information on the views among Pakistani physicians regarding AMR and the benefits of hospital antimicrobial stewardship implementation. This study was designed to explore the physicians’ views about ASP. Methods: Qualitative face-to-face and telephonic interviews were conducted by using purposive sampling method with 22 physicians working in seven tertiary care public hospitals of Punjab, Pakistan. All interviews were audio recorded and transcribed verbatim. Qualitative software was used, and a thematic analysis was conducted. Results: Three broad themes were identified: (1) the growing concern of antimicrobial resistance in Pakistan, (2) the role(s) of healthcare professionals in antibiotic prescribing, and (3) managing antibiotic resistance in hospitals. Inadequate resources, poor healthcare facilities, and insufficiently trained medical staff were the major hurdles in ASP implementation in Pakistan. Conclusions: Our study found a poor familiarity of hospital ASP among physicians working in public sector tertiary care teaching hospitals, and a number of distinct themes emerged during this study that could be helpful in establishing the concept of hospital ASP in Pakistan. Overall, physicians showed a positive attitude towards the enforcement of ASP in all healthcare settings, including teaching hospitals
Theory of Multiphonon Excitation in Heavy-Ion Collisions
We study the effects of channel coupling in the excitation dynamics of giant
resonances in relativistic heavy ions collisions. For this purpose, we use a
semiclassical approximation to the Coupled-Channels problem and separate the
Coulomb and the nuclear parts of the coupling into their main multipole
components. In order to assess the importance of multi-step processes, we
neglect the resonance widths and solve the set of coupled equations exactly.
Finite widths are then considered. In this case, we handle the coupling of the
ground state with the dominant Giant Dipole Resonance exactly and study the
excitation of the remaining resonances within the Coupled-Channels Born
Approximation. A comparison with recent experimental data is made.Comment: 29 pages, 7 Postscript figures available upon reques
Fluctuation-Dissipation relations in Driven Granular Gases
We study the dynamics of a 2d driven inelastic gas, by means of Direct
Simulation Monte Carlo (DSMC) techniques, i.e. under the assumption of
Molecular Chaos. Under the effect of a uniform stochastic driving in the form
of a white noise plus a friction term, the gas is kept in a non-equilibrium
Steady State characterized by fractal density correlations and non-Gaussian
distributions of velocities; the mean squared velocity, that is the so-called
{\em granular temperature}, is lower than the bath temperature. We observe that
a modified form of the Kubo relation, which relates the autocorrelation and the
linear response for the dynamics of a system {\em at equilibrium}, still holds
for the off-equilibrium, though stationary, dynamics of the systems under
investigation. Interestingly, the only needed modification to the equilibrium
Kubo relation is the replacement of the equilibrium temperature with an
effective temperature, which results equal to the global granular temperature.
We present two independent numerical experiment, i.e. two different observables
are studied: (a) the staggered density current, whose response to an impulsive
shear is proportional to its autocorrelation in the unperturbed system and (b)
the response of a tracer to a small constant force, switched on at time ,
which is proportional to the mean-square displacement in the unperturbed
system. Both measures confirm the validity of Kubo's formula, provided that the
granular temperature is used as the proportionality factor between response and
autocorrelation, at least for not too large inelasticities.Comment: 11 pages, 7 figures, submitted for publicatio
3D silicon microdosimetry and RBE study using C-12 ion of different energies
This paper presents a new version of the 3D mesa "bridge" microdosimeter comprised of an array of 4248 silicon cells fabricated on 10 µm thick silicon-on-insulator substrate. This microdosimeter has been designed to overcome limitations existing in previous generation silicon microdosimeters and it provides well-defined sensitive volumes and high spatial resolution. The charge collection characteristics of the new 3D mesa microdosimeter were investigated using the ANSTO heavy ion microprobe, utilizing 5.5 MeV He2+ ions. Measurement of microdosimetric quantities allowed for the determination of the Relative Biological Effectiveness of 290 MeV/u and 350 MeV/u 12C heavy ion therapy beams at the Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. The microdosimetric RBE obtained showed good agreement with the tissue-equivalent proportional counter. Utilizing the high spatial resolution of the SOI microdosimeter, the LET spectra for 70 MeV 12C+6 ions, like those present at the distal edge of 290 and 350 MeV/u beams, were obtained as the ions passed through thin layers of polyethylene film. This microdosimeter can provide useful information about the lineal energy transfer (LET) spectra downstream of the protective layers used for shielding of electronic devices for single event upset prediction
The HERMES Dual-Radiator Ring Imaging Cerenkov Detector
The construction and use of a dual radiator Ring Imaging Cerenkov(RICH)
detector is described. This instrument was developed for the HERMES experiment
at DESY which emphasizes measurements of semi-inclusive deep-inelastic
scattering. It provides particle identification for pions, kaons, and protons
in the momentum range from 2 to 15 GeV, which is essential to these studies.
The instrument uses two radiators, C4F10, a heavy fluorocarbon gas, and a wall
of silica aerogel tiles. The use of aerogel in a RICH detector has only
recently become possible with the development of clear, large homogeneous and
hydrophobic aerogel. A lightweight mirror was constructed using a newly
perfected technique to make resin-coated carbon-fiber surfaces of optical
quality. The photon detector consists of 1934 photomultiplier tubes for each
detector half, held in a soft steel matrix to provide shielding against the
residual field of the main spectrometer magnet.Comment: 25 pages, 23 figure
Systemic delivery of a DUX4-targeting antisense oligonucleotide to treat facioscapulohumeral muscular dystrophy
Facioscapulohumeral muscular dystrophy (FSHD) is one of the most prevalent skeletal muscle dystrophies. Skeletal muscle pathology in individuals with FSHD is caused by inappropriate expression of the transcription factor DUX4, which activates different myotoxic pathways. At the moment there is no molecular therapy that can delay or prevent skeletal muscle wasting in FSHD. In this study, a systemically delivered antisense oligonucleotide (ASO) targeting the DUX4 transcript was tested in vivo in ACTA1-MCM;FLExDUX4 mice that express DUX4 in skeletal muscles. We show that the DUX4 ASO was well tolerated and repressed the DUX4 transcript, DUX4 protein, and mouse DUX4 target gene expression in skeletal muscles. In addition, the DUX4 ASO alleviated the severity of skeletal muscle pathology and partially prevented the dysregulation of inflammatory and extracellular matrix genes. DUX4 ASOtreated ACTA1-MCM;FLExDUX4 mice performed better on a treadmill; however, the hanging grid and four-limb grip strength tests were not improved compared to control ASOtreated ACTA1-MCM;FLExDUX4 mice. This study shows that systemic delivery of ASOs targeting DUX4 is a promising therapeutic strategy for FSHD and strategies that further improve the ASO efficacy in skeletal muscle are warranted.Functional Genomics of Muscle, Nerve and Brain Disorder
Holographic anatomy of fuzzballs
We present a comprehensive analysis of 2-charge fuzzball solutions, that is,
horizon-free non-singular solutions of IIB supergravity characterized by a
curve on R^4. We propose a precise map that relates any given curve to a
specific superposition of R ground states of the D1-D5 system. To test this
proposal we compute the holographic 1-point functions associated with these
solutions, namely the conserved charges and the vacuum expectation values of
chiral primary operators of the boundary theory, and find perfect agreement
within the approximations used. In particular, all kinematical constraints are
satisfied and the proposal is compatible with dynamical constraints although
detailed quantitative tests would require going beyond the leading supergravity
approximation. We also discuss which geometries may be dual to a given R ground
state. We present the general asymptotic form that such solutions must have and
present exact solutions which have such asymptotics and therefore pass all
kinematical constraints. Dynamical constraints would again require going beyond
the leading supergravity approximation.Comment: 87 pages, begins with 10 page self contained summary of
results;v2:JHEP version; v3: typos corrected, see in particular formula D.1
Fine root biomass and root length density in a lowland and a montane tropical rain forest, SP, Brazil
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