1,369 research outputs found
Thank you to all our manuscript reviewers in 2015
The editors of Hereditary Cancer in Clinical Practice would like to thank all our reviewers who have contributed to the journal in 2015. Without the participation of skilful reviewers, no academic journal could succeed, and we are grateful to the committed individuals who have given their time and expertise to the peer review of manuscripts for Hereditary Cancer in Clinical Practice. We look forward to your continued support in 2016
The Second INTEGRAL AGN Catalogue
The INTEGRAL mission provides a large data set for studying the hard X-ray
properties of AGN and allows testing of the unified scheme for AGN. We present
analysis of INTEGRAL IBIS/ISGRI, JEM-X, and OMC data for 199 AGN supposedly
detected by INTEGRAL above 20 keV. The data analysed here allow a significant
spectral extraction on 148 objects and an optical variability study of 57 AGN.
The slopes of the hard X-ray spectra of Seyfert 1 and Seyfert~2 galaxies are
found to be consistent within the uncertainties, whereas higher cut-off
energies and lower luminosities are measured for the more absorbed / type 2
AGN. The intermediate Seyfert 1.5 objects exhibit hard X-ray spectra consistent
with those of Seyfert 1. When applying a Compton reflection model, the
underlying continua appear the same in Seyfert 1 and 2 with photon index 2, and
the reflection strength is about R = 1, when assuming different inclination
angles. A significant correlation is found between the hard X-ray and optical
luminosity and the mass of the central black hole in the sense that the more
luminous objects appear to be more massive. There is also a general trend
toward the absorbed sources and type 2 AGN having lower Eddington ratios. The
black holemass appears to form a fundamental plane together with the optical
and X-ray luminosity of the form Lv being proportional to Lx^0.6 M^0.2, similar
to that found between radio luminosity Lr, Lx, and M. The unified model for
Seyfert galaxies seems to hold, showing in hard X-rays that the central engine
is the same in Seyfert 1 and 2, but seen under different inclination angles and
absorption. (Abridged)Comment: 26 pages, 16 figures, accepted for publication in A&A. Corrections by
language editor included in version
Multiwavelength campaign on Mrk 509: testing realistic comptonization models
Mrk 509 was observed by XMM-Newton and INTEGRAL in October/November 2009, with one observation every four days for a total of ten observations. Each observation has been fitted with a realistic thermal Comptonization model for the continuum emission. Prompted by the correlation between the UV and soft X-ray flux, we used a thermal Comptonization component for the soft X-ray excess. The UV to X-ray/gamma-ray emission of Mrk 509 can be well fitted by these components, pointing to the existence of a hot (kT ⌠100 keV), optically-thin (Ï âŒ 0.5) corona producing the primary continuum. In contrast, the soft X-ray component requires a warm (kT ⌠1 keV), optically-thick (Ï âŒ 10-20) plasma. Estimates of the amplification ratio for this warm plasma support a configuration relatively close to the âtheoreticalâ configuration of a slab corona above a passive disk. This plasma could be the warm upper layer of the accretion disk. In contrast, the hot corona has a more photon-starved geometry. The high temperature (⌠100 eV) of the soft-photon field entering and cooling it favors a localization of the hot corona in the inner flow. This soft-photon field could be part of the comptonized emission produced by the warm plasma
Multiwavelength campaign on Mrk 509 XII. Broad band spectral analysis
(Abridged) The simultaneous UV to X-rays/gamma rays data obtained during the
multi-wavelength XMM/INTEGRAL campaign on the Seyfert 1 Mrk 509 are used in
this paper and tested against physically motivated broad band models. Each
observation has been fitted with a realistic thermal comptonisation model for
the continuum emission. Prompted by the correlation between the UV and soft
X-ray flux, we use a thermal comptonisation component for the soft X-ray
excess. The UV to X-rays/gamma-rays emission of Mrk 509 can be well fitted by
these components. The presence of a relatively hard high-energy spectrum points
to the existence of a hot (kT~100 keV), optically-thin (tau~0.5) corona
producing the primary continuum. On the contrary, the soft X-ray component
requires a warm (kT~1 keV), optically-thick (tau~15) plasma. Estimates of the
amplification ratio for this warm plasma support a configuration close to the
"theoretical" configuration of a slab corona above a passive disk. An
interesting consequence is the weak luminosity-dependence of its emission, a
possible explanation of the roughly constant spectral shape of the soft X-ray
excess seen in AGNs. The temperature (~ 3 eV) and flux of the soft-photon field
entering and cooling the warm plasma suggests that it covers the accretion disk
down to a transition radius of 10-20 . This plasma could be the
warm upper layer of the accretion disk. On the contrary the hot corona has a
more photon-starved geometry. The high temperature ( 100 eV) of the
soft-photon field entering and cooling it favors a localization of the hot
corona in the inner flow. This soft-photon field could be part of the
comptonised emission produced by the warm plasma. In this framework, the change
in the geometry (i.e. ) could explain most of the observed flux and
spectral variability.Comment: 19 pages, 14 figures. Accepted for publication in A&
Information on antiprotonic atoms and the nuclear periphery from the PS209 experiment
In the PS209 experiments at CERN two kinds of measurements were performed:
the in-beam measurement of X-rays from antiprotonic atoms and the
radiochemical, off-line determination of the yield of annihilation products
with mass number A_t -1 (less by 1 than the target mass). Both methods give
observables which allows to study the peripheral matter density composition and
distribution.Comment: LaTeX (espcrc1 style), 6 pages, 3 EPS figures, 1 table, Proceedings
of the Sixth Biennal Conference on Low-Energy Antiproton Physics LEAP 2000,
Venice, Ital
Cochlear Implants in the Workplace: A Nationwide Survey
A nation wide survey of cochlear implant recipients was conducted to study how implants may impact people at work. Using a self-reporting questionnaire, recipients using four cochlear implant designs were surveyed about spoken communication on the job, overall job performance, job satisfaction, confidence in job retention and in seeking new employment, job promotion, and income. Of the implant recipients using their implants at work (106 people), the majority used their implants during all work hours and reported positive changes in their job situations. The survey results suggest that cochlear implants may help in mitigating functional limitations in the workplace resulting from profound hearing loss
Long term study of the seismic environment at LIGO
The LIGO experiment aims to detect and study gravitational waves using ground
based laser interferometry. A critical factor to the performance of the
interferometers, and a major consideration in the design of possible future
upgrades, is isolation of the interferometer optics from seismic noise. We
present the results of a detailed program of measurements of the seismic
environment surrounding the LIGO interferometers. We describe the experimental
configuration used to collect the data, which was acquired over a 613 day
period. The measurements focused on the frequency range 0.1-10 Hz, in which the
secondary microseismic peak and noise due to human activity in the vicinity of
the detectors was found to be particularly critical to interferometer
performance. We compare the statistical distribution of the data sets from the
two interferometer sites, construct amplitude spectral densities of seismic
noise amplitude fluctuations with periods of up to 3 months, and analyze the
data for any long term trends in the amplitude of seismic noise in this
critical frequency range.Comment: To be published in Classical and Quantum Gravity. 24 pages, 15
figure
Sex differences in mathematics and reading achievement are inversely related: within- and across-nation assessment of 10 years of PISA data
We analyzed one decade of data collected by the Programme for International Student Assessment (PISA), including the mathematics and reading performance of nearly 1.5 million 15 year olds in 75 countries. Across nations, boys scored higher than girls in mathematics, but lower than girls in reading. The sex difference in reading was three times as large as in mathematics. There was considerable variation in the extent of the sex differences between nations. There are countries without a sex difference in mathematics performance, and in some countries girls scored higher than boys. Boys scored lower in reading in all nations in all four PISA assessments (2000, 2003, 2006, 2009). Contrary to several previous studies, we found no evidence that the sex differences were related to nationsâ gender equality indicators. Further, paradoxically, sex differences in mathematics were consistently and strongly inversely correlated with sex differences in reading: Countries with a smaller sex difference in mathematics had a larger sex difference in reading and vice versa. We demonstrate that this was not merely a between-nation, but also a within-nation effect. This effect is related to relative changes in these sex differences across the performance continuum: We did not find a sex difference in mathematics among the lowest performing students, but this is where the sex difference in reading was largest. In contrast, the sex difference in mathematics was largest among the higher performing students, and this is where the sex difference in reading was smallest. The implication is that if policy makers decide that changes in these sex differences are desired, different approaches will be needed to achieve this for reading and mathematics. Interventions that focus on high-achieving girls in mathematics and on low achieving boys in reading are likely to yield the strongest educational benefits
MAXI J1659-152: the shortest orbital period black-hole binary
Following the detection of a bright new X-ray source, MAXI J1659-152, a
series of observations was triggered with almost all currently flying
high-energy missions. We report here on XMM-Newton, INTEGRAL and RXTE
observations during the early phase of the X-ray outburst of this transient
black-hole candidate. We confirm the dipping nature in the X-ray light curves.
We find that the dips recur on a period of 2.4139+/-0.0005 hrs, and interpret
this as the orbital period of the system. It is thus the shortest period
black-hole X-ray binary known to date. Using the various observables, we derive
the properties of the source. The inclination of the accretion disk with
respect to the line of sight is estimated to be 60-75 degrees. The companion
star to the black hole is possibly a M5 dwarf star, with a mass and radius of
about 0.15 M_sun and 0.23 R_sun, respectively. The system is rather compact
(orbital separation is about 1.35 R_sun) and is located at a distance of
roughly 7 kpc. In quiescence, MAXI J1659-152 is expected to be optically faint,
about 28 mag in the V-band.Comment: 5 pages, 4 figures, to be published in the proceedings of the 4th
International MAXI Workshop `The First Year of MAXI: Monitoring variable
X-ray sources', 2010 Nov 30 - Dec 2, Tokyo, Japa
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