346 research outputs found
X-rays from Radio-Galaxies: BeppoSAX Observations
We briefly review BeppoSAX observations of X-ray bright radio-galaxies. Their
X-ray spectra are quite varied, and perhaps surprisingly, any similarity
between radio-loud AGN and Seyfert galaxies is the exception rather than the
rule. When detected, reprocessing features (iron line and reflection) are
generally weak, suggesting two possible scenarios: either: (1) non-thermal
(jet?) radiation dilutes the X-ray emission from the disk in radio-loud
objects, or (2) the solid angle subtended by the X-ray reprocessing material is
smaller in radio-loud than in radio-quiet AGN due to different characteristics
of the accretion disk itself.Comment: 6 pages, to appear in `Life Cycles of Radio Galaxies', ed. J. Biretta
et al., New Astronomy Review
Comparison of and Quasielastic Scattering
We formulate -nucleus quasielastic scattering in a manner which closely
parallels standard treatments of -nucleus quasielastic scattering. For
scattering, new responses involving scalar contributions appear in
addition to the Coulomb (or longitudinal) and transverse responses
which are of vector character. We compute these responses using both nuclear
matter and finite nucleus versions of the Relativistic Hartree Approximation to
Quantum Hadrodynamics including RPA correlations. Overall agreement with
measured responses and new quasielastic scattering data for
Ca at |\qs|=500 MeV/c is good. Strong RPA quenching is essential for
agreement with the Coulomb response. This quenching is notably less for the
cross section even though the new scalar contributions are even more
strongly quenched than the vector contributions. We show that this
``differential quenching'' alters sensitive cancellations in the expression for
the cross section so that it is reduced much less than the individual
responses. We emphasize the role of the purely relativistic distinction between
vector and scalar contributions in obtaining an accurate and consistent
description of the and data within the framework of our nuclear
structure model.Comment: 26 pages, 5 uuencoded figures appended to end of this fil
Foreground removal from WMAP 7yr polarization maps using an MLP neural network
One of the fundamental problems in extracting the cosmic microwave background
signal (CMB) from millimeter/submillimeter observations is the pollution by
emission from the Milky Way: synchrotron, free-free, and thermal dust emission.
To extract the fundamental cosmological parameters from CMB signal, it is
mandatory to minimize this pollution since it will create systematic errors in
the CMB power spectra. In previous investigations, it has been demonstrated
that the neural network method provide high quality CMB maps from temperature
data. Here the analysis is extended to polarization maps. As a concrete
example, the WMAP 7-year polarization data, the most reliable determination of
the polarization properties of the CMB, has been analysed. The analysis has
adopted the frequency maps, noise models, window functions and the foreground
models as provided by the WMAP Team, and no auxiliary data is included. Within
this framework it is demonstrated that the network can extract the CMB
polarization signal with no sign of pollution by the polarized foregrounds. The
errors in the derived polarization power spectra are improved compared to the
errors derived by the WMAP Team.Comment: Accepted for publication in Astrophysics & Space Scienc
Numerical Solutions of ideal two-fluid equations very closed to the event horizon of Schwarzschild black hole
The 3+1 formalism of Thorne, Price and Macdonald has been used to derive the
linear two-fluid equations describing transverse and longitudinal waves
propagating in the two-fluid ideal collisionless plasmas surrounding a
Schwarzschild black hole. The plasma is assumed to be falling in radial
direction toward the event horizon. The relativistic two-fluid equations have
been reformulate, in analogy with the special relativistic formulation as
explained in an earlier paper, to take account of relativistic effects due to
the event horizon. Here a WKB approximation is used to derive the local
dispersion relation for these waves and solved numerically for the wave number
k.Comment: 16 pages, 15 figures. arXiv admin note: text overlap with
arXiv:0902.3766, arXiv:0807.459
Role of hyaluronan in human adipogenesis : evidence from in-vitro and in-vivo studies
Hyaluronan (HA), an extra-cellular matrix glycosaminoglycan, may play a role in mesenchymal stem cell differentiation to fat but results using murine models and cell lines are conflicting. Our previous data, illustrating decreased HA production during human adipogenesis, suggested an inhibitory role. We have investigated the role of HA in adipogenesis and fat accumulation using human primary subcutaneous preadipocyte/fibroblasts (PFs, n = 12) and subjects of varying body mass index (BMI). The impact of HA on peroxisome proliferator-activated receptor gamma (PPARÎł) expression was analysed following siRNA knockdown or HA synthase (HAS)1 and HAS2 overexpression. PFs were cultured in complete or adipogenic medium (ADM) with/without 4-methylumbelliferone (4-MU = HA synthesis inhibitor). Adipogenesis was evaluated using oil red O (ORO), counting adipogenic foci, and measurement of a terminal differentiation marker. Modulating HA production by HAS2 knockdown or overexpression increased (16%, p < 0.04) or decreased (30%, p = 0.01) PPARÎł transcripts respectively. The inhibition of HA by 4-MU significantly enhanced ADM-induced adipogenesis with 1.52 ± 0.18- (ORO), 4.09 ± 0.63- (foci) and 2.6 ± 0.21-(marker)-fold increases compared with the controls, also increased PPARÎł protein expression (40%, (p < 0.04)). In human subjects, circulating HA correlated negatively with BMI and triglycerides (r = â0.396 (p = 0.002), r = â0.269 (p = 0.038), respectively), confirming an inhibitory role of HA in human adipogenesis. Thus, enhancing HA action may provide a therapeutic target in obesity
VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager
In this paper we describe in detail the implementation and main properties of
a new inversion code for the polarized radiative transfer equation (VFISV: Very
Fast inversion of the Stokes vector). VFISV will routinely analyze pipeline
data from the Helioseismic and Magnetic Imager (HMI) on-board of the Solar
Dynamics Observatory (SDO). It will provide full-disk maps (40964096
pixels) of the magnetic field vector on the Solar Photosphere every 10 minutes.
For this reason VFISV is optimized to achieve an inversion speed that will
allow it to invert 16 million pixels every 10 minutes with a modest number
(approx. 50) of CPUs. Here we focus on describing a number of important
details, simplifications and tweaks that have allowed us to significantly speed
up the inversion process. We also give details on tests performed with data
from the spectropolarimeter on-board of the Hinode spacecraft.Comment: 23 pages, 9 figures (2 color). Submitted for publication to Solar
Physic
Active Galaxies in the UV
In this article we present different aspects of AGN studies demonstrating the
importance of the UV spectral range. Most important diagnostic lines for
studying the general physical conditions as well as the metalicities in the
central broad line region in AGN are emitted in the UV. The UV/FUV continuum in
AGN excites not only the emission lines in the immediate surrounding but it is
responsible for the ionization of the intergalactic medium in the early stages
of the universe. Variability studies of the emission line profiles of AGN in
the UV give us information on the structure and kinematics of the immediate
surrounding of the central supermassive black hole as well as on its mass
itself.Comment: 29 pages, 13 figures, Ap&SS in pres
Nothophytophthora gen. nov., a new sister genus of Phytophthora from natural and semi-natural ecosystem
During various surveys of Phytophthora diversity in Europe, Chile and Vietnam slow growing oomycete
isolates were obtained from rhizosphere soil samples and small streams in natural and planted forest stands.
Phylogenetic analyses of sequences from the nuclear ITS, LSU, ÎČ-tubulin and HSP90 loci and the mitochondrial
cox1 and NADH1 genes revealed they belong to six new species of a new genus, officially described here as
Nothophytophthora gen. nov., which clustered as sister group to Phytophthora. Nothophytophthora species share
numerous morphological characters with Phytophthora: persistent (all Nothophytophthora spp.) and caducous
(N. caduca, N. chlamydospora, N. valdiviana, N. vietnamensis) sporangia with variable shapes, internal differentiation
of zoospores and internal, nested and extended (N. caduca, N. chlamydospora) and external (all Nothophytophthora
spp.) sporangial proliferation; smooth-walled oogonia with amphigynous (N. amphigynosa) and paragynous
(N. amphigynosa, N. intricata, N. vietnamensis) attachment of the antheridia; chlamydospores (N. chlamydospora)
and hyphal swellings. Main differing features of the new genus are the presence of a conspicuous, opaque plug
inside the sporangiophore close to the base of most mature sporangia in all known Nothophytophthora species and
intraspecific co-occurrence of caducity and non-papillate sporangia with internal nested and extended proliferation
in several Nothophytophthora species. Comparisons of morphological structures of both genera allow hypotheses
about the morphology and ecology of their common ancestor which are discussed. Production of caducous sporangia
by N. caduca, N. chlamydospora and N. valdiviana from Valdivian rainforests and N. vietnamensis from a
mountain forest in Vietnam suggests a partially aerial lifestyle as adaptation to these humid habitats. Presence of
tree dieback in all forests from which Nothophytophthora spp. were recovered and partial sporangial caducity of
several Nothophytophthora species indicate a pathogenic rather than a saprophytic lifestyle. Isolation tests from
symptomatic plant tissues in these forests and pathogenicity tests are urgently required to clarify the lifestyle of the
six Nothophytophthora species.info:eu-repo/semantics/publishedVersio
Glucose self-monitoring in non-insulin-treated patients with type 2 diabetes in primary care settings: A randomized trial
IMPORTANCE The value of self-monitoring of blood glucose (SMBG) levels in patients with non-insulin-treated type 2 diabetes has been debated. OBJECTIVE To compare 3 approaches of SMBG for effects on hemoglobin A1c levels and health-related quality of life (HRQOL) among people with non-insulin-treated type 2 diabetes in primary care practice. DESIGN, SETTING, AND PARTICIPANTS The Monitor Trial studywas a pragmatic, open-label randomized trial conducted in 15 primary care practices in central North Carolina. Participants were randomized between January 2014 and July 2015. Eligible patients with type 2 non-insulin-treated diabetes were: older than 30 years, established with a primary care physician at a participating practice, had glycemic control (hemoglobin A1c) levels higher than 6.5%but lower than 9.5%within the 6 months preceding screening, as obtained from the electronic medical record, and willing to comply with the results of random assignment into a study group. Of the 1032 assessed for eligibility, 450 were randomized. INTERVENTIONS No SMBG, once-daily SMBG, and once-daily SMBG with enhanced patient feedback including automatic tailored messages delivered via the meter. MAIN OUTCOMES AND MEASURES Coprimary outcomes included hemoglobin A1c levels and HRQOL at 52 weeks. RESULTS A total of 450 patients were randomized and 418 (92.9%) completed the final visit. There were no significant differences in hemoglobin A1c levels across all 3 groups (P = .74; estimated adjusted mean hemoglobin A1c difference, SMBG with messaging vs no SMBG, -0.09%; 95%CI, -0.31% to 0.14%; SMBG vs no SMBG, -0.05%; 95%CI, -0.27%to 0.17%). There were also no significant differences found in HRQOL. There were no notable differences in key adverse events including hypoglycemia frequency, health care utilization, or insulin initiation. CONCLUSIONS AND RELEVANCE In patients with non-insulin-treated type 2 diabetes, we observed no clinically or statistically significant differences at 1 year in glycemic control or HRQOL between patients who performed SMBG compared with those who did not perform SMBG. The addition of this type of tailored feedback provided through messaging via ameter did not provide any advantage in glycemic control
Dimensionless cosmology
Although it is well known that any consideration of the variations of
fundamental constants should be restricted to their dimensionless combinations,
the literature on variations of the gravitational constant is entirely
dimensionful. To illustrate applications of this to cosmology, we explicitly
give a dimensionless version of the parameters of the standard cosmological
model, and describe the physics of Big Bang Neucleosynthesis and recombination
in a dimensionless manner. The issue that appears to have been missed in many
studies is that in cosmology the strength of gravity is bound up in the
cosmological equations, and the epoch at which we live is a crucial part of the
model. We argue that it is useful to consider the hypothetical situation of
communicating with another civilization (with entirely different units),
comparing only dimensionless constants, in order to decide if we live in a
Universe governed by precisely the same physical laws. In this thought
experiment, we would also have to compare epochs, which can be defined by
giving the value of any {\it one} of the evolving cosmological parameters. By
setting things up carefully in this way one can avoid inconsistent results when
considering variable constants, caused by effectively fixing more than one
parameter today. We show examples of this effect by considering microwave
background anisotropies, being careful to maintain dimensionlessness
throughout. We present Fisher matrix calculations to estimate how well the fine
structure constants for electromagnetism and gravity can be determined with
future microwave background experiments. We highlight how one can be misled by
simply adding to the usual cosmological parameter set
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