443 research outputs found
Primordial non-Gaussianity with -type and -type spectral distortions: exploiting Cosmic Microwave Background polarization and dealing with secondary sources
Cross-correlations between Cosmic Microwave Background (CMB) temperature and
-spectral distortions anisotropies have been previously proposed as a way to
measure the local bispectrum parameter in a range of
scales inaccessible to either CMB (, ) bispectra or -
correlations. This is useful e.g. to test scale dependence of primordial
non-Gaussianity. Unfortunately, the primordial -T signal is strongly
contaminated by the late-time correlation between the Integrated Sachs Wolfe
and Sunyaev-Zel'dovich (SZ) effects. Moreover, SZ itself generates a large
noise contribution in the -parameter map. We consider two original ways to
address these issues. In order to remove the bias due to the SZ-CMB temperature
coupling, while also adding new signal, we include in the analysis the
cross-correlation between -distortions and CMB {\em polarization}. In order
to reduce the noise, we propose to clean the -map by subtracting a SZ
template, reconstructed via cross-correlation with external tracers (CMB and
galaxy-lensing signals). We combine this SZ template subtraction with the
previously adopted solution of directly masking detected clusters. Our final
forecasts show that, using -distortions, a PRISM-like survey can achieve
, while an ideal experiment will achieve
, with improvements of a factor
from adding the - signal, and a further from template
cleaning. These forecasts are much worse than current
boundaries from {\em Planck}, but we stress again that they refer to completely
different scales.Comment: 24 pages, 5 figure
Esecutivo e giurisdizione nell’ amministrazione straordinaria delle imprese in crisi di rilevanti dimensioni
la tesi si basa su un'analisi sistematica della procedura di amministrazione straordinaria "speciale",introdotta dal D.L. 347/03 ed innovata con il D.L. 134/08 e il D.L.1/15, ponendo l'attenzione sopratutto ai rapporti ed ai ruoli svolti rispettivamente dall esecutivo e dal Tribunale nelle dinamiche della procedur
Characterization and assessment of PAH content in spent char to be used for soil amendment and carbon sequestration
Cost minimization analysis of BoNT-As in the treatment of upper limb spasticity and cervical dystonia
Botulinum toxin type A (BoNT-A) injections are recommended for the management of upper limb spasticity (ULS) and cervical dystonia (CD). The main aim of this cost minimization analysis (CMA) was to compare the annual cost per patient for three BoNT-As (Botox®, Dysport® and Xeomin®) in the treatment of ULS or CD in Italy. A budget impact analysis (BIA) was also conducted.
Methods
The CMA was conducted from the perspective of the Italian National Health Service. Only direct medical costs (BoNT-A and standard therapy) were considered. By using a Delphi panel of twelve Italian Experts in the treatment of ULS and CD, data was collected about BoNT-As (dose, number of administrations and acquisition price) and standard therapy (concomitant medications, visits, Day-Hospital, hospitalizations, etc.). Costs were assessed in Euros 2014. The BIA was conducted to evaluate the pharmaceutical expenditure for the three BoNT-As on a five-year time horizon. A sensitivity analysis was conducted.
Results
The mean annual cost per patient with ULS was €1,840.20 with Dysport®, €2,067.12 with Botox® and €2,171.05 with Xeomin®. The mean annual cost per patient with CD was €1,353.79 with Dysport®, €1,433.12 with Botox® and €1,503.60 with Xeomin®. In the time horizon considered, the substitution process of Botox® and Xeomin® by Dysport® would result in a total saving of €620,000 when treating ULS and a total saving of €481,000 in the case of CD. Sensitivity and probabilistic analyses showed the robustness of results.
Conclusions
From the Italian National Health Service's perspective, Dysport® appears to be the cost-saving therapeutic option compared with Botox® and Xeomin® in the treatment of ULS or CD
Spectro-spatial evolution of the CMB II: generalised Boltzmann hierarchy
In this paper, we formulate a generalised photon Boltzmann hierarchy that
allows us to model the evolution and creation of spectral distortion
anisotropies in the early Universe. We directly build on our first paper in
this series, extending the thermalisation Green's function treatment to the
anisotropic case. We show that the problem can be described with the common
Boltzmann hierarchy for the photon field extended by new spectral parameters --
a step that reduces the complexity of the calculation by at least two orders of
magnitude. Our formalism describes the effects of i) Doppler and potential
driving, ii) spectral evolution by Compton scattering, iii) perturbed
thermalisation and iv) anisotropic heating on the distortion anisotropies. We
highlight some of the main physical properties of the equations and also
outline the steps for computing CMB power spectra including distortion
anisotropies. Limitations and extensions of the formulation are also briefly
discussed. The novel Boltzmann hierarchy given here is the basis for a series
of companion papers studying how distortion anisotropies evolve in the
perturbed Universe and which physical processes could be constrained using
future CMB imaging techniques.Comment: 35 pages, 1 figure, to be submitted to JCAP; comments welcom
Improved calculations of electron–ion bremsstrahlung Gaunt factors for astrophysical applications
Electron-ion Bremsstrahlung (free-free) emission and absorption occur in many
astrophysical plasmas for a wide range of physical conditions. This classical
problem has been studied multiple times, and many analytical and numerical
approximations exist. However, accurate calculations of the transition from the
non-relativistic to the relativistic regime remain sparse. Here we provide a
comprehensive study of the free-free Gaunt factors for ions with low charge
(Z<=10). We compute the Gaunt factor using the expressions for the differential
cross section given by Elwert & Haug (EH) and compare to various limiting
cases. We develop a new software package, BRpack, for direct numerical
applications. This package uses a combination of pre-computed tables and
analytical approximations to efficiently cover a wide range of electron and
photon energies, providing a representation of the EH Gaunt factor to better
than 0.03% precision for Z<=2. Our results are compared to those of previous
studies highlighting the improvements achieved here. BRpack should be useful in
computations of spectral distortions of the cosmic microwave background,
radiative transfer problems during reionization or inside galaxy clusters, and
the modeling of galactic free-free foregrounds. The developed computational
methods can furthermore be extended to higher energies and ion charge.Comment: 12 pages + 5 pages appendix and references, 17 figures, to be
submitted to MNRAS, BRpack will be made available at www.chluba.de/BRpac
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