6,416 research outputs found
Axions and SN1987A
The effect of free-streaming axion emission on numerical models for the cooling of the newly born neutron star associated with SN1987A is considered. It is found that for an axion mass of greater than approximately 10 to the -3 eV, axion emission shortens the duration of the expected neutrino burst so significantly that it would be inconsistent with the neutrino observations made by the Kamiokande II and Irvine-Michigan-Brookhaven detectors. However, the possibility has not been investigated that axion trapping (which should occur for masses greater than or equal to 0.02 eV) sufficiently reduces axion emission so that axion masses greater than approximately 2 eV would be consistent with the neutrino observations
Alveolar macrophages and the diagnosis of drowning
In the present study, we examined the number of alveolar macrophages in lung tissue from 17 cases of fresh water drowning, 22 cases of acute death and 6 cases of lung emphysema. When counting only the number of alveolar macrophages per alveolus without consideration of the alveolar size we found no relevant differences between the groups investigated. To exclude any influence of the alveolar size on the results the surface density of the alveolar macrophages and interstitial tissue was estimated and compared in the different groups. In cases of drowning, the lungs showed significantly lower values in both categories. The ratio of ‘alveolar macrophages/interstitial tissue’ was also reduced in cases of drowning in comparison to the other groups, however, without significant differences. These morphometrical results characterizing the ‘emphysema aquosum’ with almost ‘empty’ and dilated alveoli could be explained by a wash-out effect of the drowning fluid leading to a partial removal of the macrophages from the alveoli. This hypothesis was confirmed by the detection of alveolar macrophages in the drowning froth by immunohistochemical analysis. Even though alveolar macrophages were unambiguously identified in advanced putrefied lungs in HE-stained sections as well as by immunohistochemical staining, an estimation of the number of these cells cannot provide further information for the diagnosis of drowning in putrefied corpses due to the autolytic destruction of the lung architecture providing no reliable values
SDSS AGNs with X-ray Emission from ROSAT PSPC Pointed Observations
We present a sample of 1744 type 1 active galactic nuclei (AGNs) from the
Sloan Digital Sky Survey (SDSS DR4) spectroscopic catalog with X-ray
counterparts in the White-Giommi-Angelini Catalog (WGACAT) of ROSAT PSPC
pointed observations. Of 1744 X-ray sources, 1410 (80.9%) are new AGN
identifications. Of 4574 SDSS DR4 AGNs for which we found radio matches in the
catalog of radio sources from the FIRST catalog, 224 turned up in our sample of
SDSS X-ray AGNs. The sample objects are given in a catalog that contains
optical and X-ray parameters along with radio emission parameters where
available. We illustrate the content of our catalog and its potential for AGN
science by providing statistical relationships for the catalog data. The
potential of the morphological information is emphasized by confronting the
statistics of optically resolved and unresolved AGNs. The immediate properties
of the catalog objects include significant correlation of X-ray and optical
fluxes, which is consistent with expectations. Also expected is the decrease of
X-ray flux toward higher redshifts. The X-ray to optical flux ratio for the
unresolved AGNs exhibits a decline toward higher redshifts, in agreement with
previous results. The resolved AGNs, however, display the opposite trend. At a
given optical brightness, X-ray fluxes of radio-quiet AGNs by a factor of 2. We
caution, however, that because of the variety of selection effects present in
both the WGACAT and the SDSS, the interpretation of any relationships based on
our sample of X-ray AGNs requires a careful analysis of these effects.Comment: 34 pages, 18 figure
Prospects for CW and LP operation of the European XFEL in hard X-ray regime
The European XFEL will operate nominally at 17.5 GeV in SP (short pulse) mode
with 0.65 ms long bunch train and 10 Hz repetition rate. A possible upgrade of
the linac to CW (continuous wave) or LP (long pulse) modes with a corresponding
reduction of electron beam energy is under discussion since many years. Recent
successes in the dedicated R&D program allow to forecast a technical
feasibility of such an upgrade in the foreseeable future. One of the challenges
is to provide sub-Angstrom FEL operation in CW and LP modes. In this paper we
perform a preliminary analysis of a possible operation of the European XFEL in
the hard X-ray regime in CW and LP modes with the energies of 7 GeV and 10 GeV,
respectively. We consider lasing in the baseline XFEL undulator as well as in a
new undulator with a reduced period. We show that, with reasonable requirements
on electron beam quality, lasing on the fundamental will be possible in
sub-Angstrom regime. As an option for generation of brilliant photon beams at
short wavelengths we also consider harmonic lasing that has recently attracted
a significant attention
Thyroid hormones correlate with field metabolic rate in ponies, Equus ferus caballus
Acknowledgments The authors thank Jürgen Dörl for technical help and for taking care of the animals and Peter Thompson for technical assistance with the doubly labelled water analysis. Funding The study was supported by a grant from the German Research Foundation (DFG;GE 704/13-1).Peer reviewedPublisher PD
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