2,441 research outputs found
Neutrino Spin Transitions and the Violation of the Equivalence Principle
The violation of the equivalence principle (VEP) causing neutrino
oscillations is of current interest. We study here the possibility of not only
flavor oscillation but spin flavor oscillation of ultra high energy ( 1
PeV) neutrinos emanating from AGN due to VEP and due to the presence of a large
magnetic field ( 1 Tesla) in AGN. In particular we look at the resonance
spin flavor conversion driven by the AGN potential. Interesting bounds on the
transition magnetic moment of neutrinos may therefore be obtained.Comment: Latex, 12 pages, no figures. To appear in Journal of Physics G:
Nuclear and Particle Physics. Two references adde
Опыт участия в международном летнем кампусе РАНХиГС 2017
Extraordinarily well-preserved chitinozoans from an Upper Silurian sedimentary sequence in south-east Turkey were recovered from different depth levels, hand-picked from the palynological residue, cleaned and analysed by micro-FTIR and Curie point pyrolysis-gas chromatography-mass spectrometry. Hand-picked chitinozoans were predominantly represented by the genera Bursachitina, Calpichitina, Cingulochitina, Ancyrochitina, Angochitina and Pterochitina. Both spectroscopic and pyrolytic investigations suggest that biogeomacromolecules of these Chitinozoa consist of both aliphatic and aromatic moieties. The micro-FTIR spectra of Chitinozoa are characterized by aliphatic CH, (3000-2800 and 1460-1450 cm(-1)) and CH3 (1375 cm(-1)) absorptions and aromatic C = C (1560-1610 cm(-1)) and CH (3050 cm(-1) and 700-900 cm(-1)) absorptions. Major pyrolysis products from the Chitinozoa include both aromatic compounds such as alkylbenzenes, alkylnaphthalenes, alkylphenols and alkylphenanthrenes and aliphatic hydrocarbons including a homologous series of n-alkene/n-alkane doublets. Aromatic compounds predominate over aliphatic compounds. 1,2,3,4-Tetramethylbenzene is the most abundant pyrolysis product of the studied Chitinozoa. No pyrolysis products diagnostic of chitin were detected in the present study and it is unlikely that the original biomacromolecules of Chitinozoa prior to fossilization were made of chitin. (c) 200
Systemic therapy for vulval Erosive Lichen Planus (the 'hELP' trial): study protocol for a randomised controlled trial
BACKGROUND: Erosive lichen planus affecting the vulva (ELPV) is a relatively rare, chronic condition causing painful raw areas in the vulvovaginal region. Symptoms are pain and burning, which impact upon daily living. There is paucity of evidence regarding therapy. A 2012 Cochrane systematic review found no randomised controlled trials (RCTs) in this field. Topically administered corticosteroids are the accepted first-line therapy: however, there is uncertainty as to which second-line treatments to use. Several systemic agents have been clinically noted to show promise for ELPV refractory to topically administered corticosteroids but there is no RCT evidence to support these. The 'hELP' study is a RCT with an internal pilot phase designed to provide high-quality evidence. METHODS/DESIGN: The objective is to test whether systemic therapy in addition to standard topical therapy is a beneficial second-line treatment for ELPV. Adjunctive systemic therapies used are hydroxychloroquine, methotrexate, mycophenolate mofetil and prednisolone. Topical therapy plus a short course of prednisolone given orally is considered the comparator intervention. The trial is a four-armed, open-label, pragmatic RCT which uses a blinded independent clinical assessor. To provide 80 % power for each comparison, 96 participants are required in total. The pilot phase aims to recruit 40 participants. The primary clinical outcome is the proportion of patients achieving treatment success at 6 months. 'Success' is defined by a composite measure of Patient Global Assessment score of 0 or 1 on a 4-point scale plus improvement from baseline on clinical photographs scored by a clinician blinded to treatment allocation. Secondary clinical outcomes include 6-month assessment of: (1) Reduction in pain/soreness; (2) Global assessment of disease; (3) Response at other affected mucosal sites; (4) Hospital Anxiety and Depression Scale scores; (5) Sexual function; (6) Health-related quality of life using 'Short Form 36' and 'Skindex-29' questionnaires; (7) Days of topical steroid use; (8) Treatment satisfaction; (9) Discontinuation of medications due to treatment failure; (10) Per participant cost of intervention in each treatment group. Adverse events will also be reported. DISCUSSION: 'hELP' is the first RCT to address second-line treatment of ELPV. The trial has encountered unique methodological challenges and has required collaborative efforts of the UK Dermatology Clinical Trials Network alongside expert clinicians. TRIAL REGISTRATION: CURRENT CONTROLLED TRIALS: ISRCTN 81883379 . Date of registration 12 June 2014
BeppoSAX Observations of the Maser Sy2 Galaxy: ESO103-G35
We have made BeppoSAX observations of the Seyfert 2/1.9 galaxy ESO103-G35,
which contains a nuclear maser source and is known to be heavily absorbed in
the X-rays. Analysis of the X-ray spectra observed by SAX in October 1996 and
1997 yields a spectral index 0.74+/-0.07, typical of Seyfert galaxies and
consistent with earlier observations of this source. The strong, soft X-ray
absorption has column density 1.79E(23)/cm^2, again consistent with earlier
results. The best fitting spectrum is that of a power law with a high energy
cutoff at 29+/-10 keV, a cold, marginally resolved Fe Kalpha line with EW 290
eV (1996) and a mildly ionized Fe K-edge at 7.37 keV. The Kalpha line and cold
absorption are consistent with origin in a accretion disk/torus through which
our line-of-sight passes at a radial distance of pc. The Fe K-edge is
mildly ionized suggesting the presence of ionized gas probably in the inner
accretion disk, close to the central source or in a separate warm absorber. The
data quality is too low to distinguish between these possibilities but the
edge-on geometry implied by the water maser emission favors the former.
Comparison with earlier observations of ESO103-G35 shows little/no change in
spectral parameters while the flux changes by factors of a few on timescales of
a few months. The 2--10 keV flux decreased by a factor of 2.7 between Oct 1996
and Oct 1997 with no detectable change in the count rate >20 keV suggesting a
constant or delayed response reflection component. The high energy cutoff is
lower than the typical 300keV values seen in Seyfert galaxies. A significant
subset of similar sources would affect current models of the AGN contribution
to the cosmic X-ray background which generally assume a high energy cutoff of
300 keV.Comment: 22 pages, postscript file, accepted for publication in Ap
Infrared Properties of High Redshift and X-ray Selected AGN Samples
The NASA/ISO Key Project on active galactic nuclei (AGN) seeks to better
understand the broad-band spectral energy distributions (SEDs) of these sources
from radio to X-rays, with particular emphasis on infrared properties. The ISO
sample includes a wide variety of AGN types and spans a large redshift range.
Two subsamples are considered herein: 8 high-redshift (1 < z < 4.7) quasars;
and 22 hard X-ray selected sources.
The X-ray selected AGN show a wide range of IR continuum shapes, extending to
cooler colors than the optical/radio sample of Elvis et al. (1994). Where a
far-IR turnover is clearly observed, the slopes are < 2.5 in all but one case
so that non-thermal emission remains a possibility. The highest redshift
quasars show extremely strong, hot IR continua requiring ~ 100 solar masses of
500 - 1000 Kelvin dust with ~ 100 times weaker optical emission. Possible
explanations for these unusual properties include: reflection of the optical
light from material above/below a torus; strong obscuration of the optical
continuum; or an intrinsic deficit of optical emission.Comment: 8 pages, 3 figures (2 color), to be published in the Springer Lecture
Notes of Physics Series as part of the proceedings for "ISO Surveys of a
Dusty Universe," a workshop held at Ringberg Castle, Germany, November 8 -
12, 1999. Requires latex style files for this series: cl2emult.cls,
cropmark.sty, lnp.sty, sprmindx.sty, subeqnar.sty (included with submission
The reddest ISO-2MASS quasar
In the course of the NIR/MIR AGN search combining the 6.7 mu ISOCAM Parallel
Survey and 2MASS we have discovered 24 type-1 quasars about a third of which
are too red to be discriminated by optical/UV search techniques. Here we report
on a detailed case study of the reddest type-1 quasar of our sample (J2341) at
redshift z=0.236 with M_K=-25.8 and J-K=1.95. We performed spectroscopy in the
optical with VLT/FORS1 and in the MIR with Spitzer as well as NIR imaging with
ISPI at CTIO. The optical and NIR observations reveal a star forming
emission-line galaxy at the same redshift as the quasar with a projected linear
separation of 1.8 arcsec (6.7 kpc). The quasar and its companion are embedded
in diffuse extended continuum emission. Compared with its companion the quasar
exhibits redder optical-NIR colours, which we attribute to hot nuclear dust.
The MIR spectrum shows only few emission lines superimposed on a power-law
spectral energy distribution. However, the lack of strong FIR emission suggests
that our potentially interacting object contains much less gas and dust and is
in a stage different from dust reddened ULIRG-AGN like Mrk 231. The optical
spectrum shows signatures for reddening in the emission-lines and no
post-starburst stellar population is detected in the host galaxy of the quasar.
The optical continuum emission of the active nucleus appears absorbed and
diluted. Even the combination of absorption and host dilution is not able to
match J2341 with standard quasar templates. While the BLR shows only a rather
moderate absorption of E_(B-V)=0.3, the continuum shorter than 4500 AA requires
strong obscuration with E_(B-V)=0.7, exceeding the constraints from the low
upper limit on the 9.7 mu silicate absorption. This leads us to conclude that
the continuum of J2341 is intrinsically redder than that of typical quasars.Comment: 8 pages, 9 figure
Fluorescence Imaging of Underexpanded Jets and Comparison with CFD
An experimental study of underexpanded and highly underexpanded axisymmetric nitrogen free jets seeded with 0.5% nitric oxide (NO) and issuing from a sonic orifice was conducted at NASA Langley Research Center. Reynolds numbers based on nozzle exit conditions ranged from 770 to 35,700, and nozzle exit-to-ambient jet pressure ratios ranged from 2 to 35. These flows were non-intrusively visualized with a spatial resolution of approximately 0.14 mm x 0.14 mm x 1 mm thick and a temporal resolution of 1 s using planar laser-induced fluorescence (PLIF) of NO, with the laser tuned to the strongly-fluorescing UV absorption bands of the Q1 band head near 226.256 nm. Three laminar cases were selected for comparison with computational fluid dynamics (CFD). The cases were run using GASP (General Aerodynamic Simulation Program) Version 4. Comparisons of the fundamental wavelength of the jet flow showed good agreement between CFD and experiment for all three test cases, while comparisons of Mach disk location and Mach disk diameter showed good agreement at lower jet pressure ratios, with a tendency to slightly underpredict these parameters with increasing jet pressure ratio
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