485 research outputs found
OBSERVATIONS ON NAVICULA THALLODES (BACILLARIOPHYCEAE), A BLADE-FORMING DIATOM FROM THE BERING SEA 1
A thallus-forming diatom, Navicula thallodes Proschkina-Lavrenko, previously known only from the original collection at Bering Island (U.S.S.R.), has been found at Amchitka Island in the Aleutians, Alaska. The most remarkable observation of the present report is that N. thallodes may form blades up to 50 cm long, which to our knowledge is the greatest length reported for a colonial diatom. SEM observations of this diatom are presented for the first time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65176/1/j.1529-8817.1988.tb04487.x.pd
Development of an international standard set of outcome measures for patients with atrial fibrillation: a report of the International Consortium for Health Outcomes Measurement (ICHOM) atrial fibrillation working group.
AIMS: As health systems around the world increasingly look to measure and improve the value of care that they provide to patients, being able to measure the outcomes that matter most to patients is vital. To support the shift towards value-based health care in atrial fibrillation (AF), the International Consortium for Health Outcomes Measurement (ICHOM) assembled an international Working Group (WG) of 30 volunteers, including health professionals and patient representatives to develop a standardized minimum set of outcomes for benchmarking care delivery in clinical settings. METHODS AND RESULTS: Using an online-modified Delphi process, outcomes important to patients and health professionals were selected and categorized into (i) long-term consequences of disease outcomes, (ii) complications of treatment outcomes, and (iii) patient-reported outcomes. The WG identified demographic and clinical variables for use as case-mix risk adjusters. These included baseline demographics, comorbidities, cognitive function, date of diagnosis, disease duration, medications prescribed and AF procedures, as well as smoking, body mass index (BMI), alcohol intake, and physical activity. Where appropriate, and for ease of implementation, standardization of outcomes and case-mix variables was achieved using ICD codes. The standard set underwent an open review process in which over 80% of patients surveyed agreed with the outcomes captured by the standard set. CONCLUSION: Implementation of these consensus recommendations could help institutions to monitor, compare and improve the quality and delivery of chronic AF care. Their consistent definition and collection, using ICD codes where applicable, could also broaden the implementation of more patient-centric clinical outcomes research in AF
Iron line profiles in Suzaku spectra of bare Seyfert galaxies
We methodically model the broad-band Suzaku spectra of a small sample of six
'bare' Seyfert galaxies: Ark 120, Fairall 9, MCG-02-14-009, Mrk 335, NGC 7469
and SWIFT J2127.4+5654. The analysis of bare Seyferts allows a consistent and
physical modelling of AGN due to a weak amount of any intrinsic warm
absorption, removing the degeneracy between the spectral curvature due to warm
absorption and the red-wing of the Fe K region. Through effective modelling of
the broad-band spectrum and investigating the presence of narrow neutral or
ionized emission lines and reflection from distant material, we obtain an
accurate and detailed description of the Fe K line region using models such as
laor, kerrdisk and kerrconv.
Results suggest that ionized emission lines at 6.7 keV and 6.97 keV
(particularly Fe XXVI) are relatively common and the inclusion of these lines
can greatly affect the parameters obtained with relativistic models i.e. spin,
emissivity, inner radius of emission and inclination. Moderately broad
components are found in all objects, but typically the emission originates from
tens of Rg, rather than within <6Rg of the black hole. Results obtained with
kerrdisk line profiles suggest an average emissivity of q~2.3 at intermediate
spin values with all objects ruling out the presence of a maximally spinning
black hole at the 90% confidence level. We also present new spin constraints
for Mrk 335 and NGC 7469 with intermediate values of a=0.70(+0.12,-0.01) and
a=0.69(+0.09,-0.09) respectively.Comment: 19 pages, 7 figures, 9 tables, MNRAS accepte
The Hot and Energetic Universe: Astrophysics of feedback in local AGN
Understanding the astrophysics of feedback in active galactic nuclei (AGN) is
key to understanding the growth and co-evolution of supermassive black holes
and galaxies. AGN-driven winds/outflows are potentially the most effective way
of transporting energy and momentum from the nuclear scales to the host galaxy,
quenching star formation by sweeping away the gas reservoir. Key questions in
this field are: 1) how do accretion disks around black holes launch
winds/outflows, and how much energy do these carry? 2) How are the energy and
metals accelerated in winds/outflows transferred and deposited into the
circumgalactic medium? X-ray observations are a unique way to address these
questions because they probe the phase of the outflows which carries most of
the kinetic energy. We show how a high throughput, high spectral resolution
instrument like the X-ray Integral Field Unit (X-IFU) on Athena+ will allow us
to address these questions by determining the physical parameters (ionization
state, density, temperature, abundances, velocities, geometry, etc.) of the
outflows on a dynamical time-scale, in a broad sample of nearby bright AGN. The
X-IFU will also allow direct spectral imaging of the impact of these winds on
the host galaxy for local AGN, forming a template for understanding AGN at
higher redshifts where wind shocks cannot be resolved.Comment: Supporting paper for the science theme "The Hot and Energetic
Universe" to be implemented by the Athena+ X-ray observatory
(http://www.the-athena-x-ray-observatory.eu). 10 pages, 6 figure
NGC454: unveiling a new "changing look" AGN
We present a detailed analysis of the X-ray spectrum of the Seyfert 2 galaxy
NGC454E, belonging to the interacting system NGC454. Observations performed
with Suzaku, XMM-Newton and Swift allowed us to detect a dramatic change in the
curvature of the 2-10 keV spectrum, revealing a significant variation of the
absorbing column density along the line of sight (from ~ 1 x10^{24}cm^{-2} to ~
1x10^{23}cm^{-2}). Consequently, we propose this source as a new member of the
class of "changing look" AGN, i.e. AGN that have been observed both in
Compton-thin (NH =10^{23 cm^{-2}) and reflection dominated states
(Compton-thick, NH >10^{24} cm^{-2}). Due to the quite long time lag (6 months)
between the Suzaku and XMM-Newton observations we cannot infer the possible
location of the obscuring material causing the observed variability. In the 6-7
keV range the XMM-Newton observation also shows a clear signature of the
presence of an ionized absorber. Since this feature is not detected during the
Suzaku observation (despite its detectability), the simplest interpretation is
that the ionized absorber is also variable; its location is estimated to be
within ~10^{-3} pc from the central black hole, probably much closer in than
the rather neutral absorber.Comment: 10 page
The first broad-band X-ray view of the narrow-line Seyfert 1 Ton S180
We present joint \textit{XMM-Newton} and \textit{NuSTAR} observations of the
`bare' narrow line Seyfert 1 Ton S180 (), carried out in 2016 and
providing the first hard X-ray view of this luminous galaxy. We find that the
0.4--30 keV band cannot be self-consistently reproduced by relativistic
reflection models, which fail to account simultaneously for the soft and hard
X-ray emission. The smooth soft excess prefers extreme blurring parameters,
confirmed by the nearly featureless nature of the RGS spectrum, while the
moderately broad Fe K line and the modest hard excess above 10 keV appear to
arise in a milder gravity regime. By allowing a different origin of the soft
excess, the broadband X-ray spectrum and overall spectral energy distribution
(SED) are well explained by a combination of: (a) direct thermal emission from
the accretion disc, dominating from the optical to the far/extreme UV; (b)
Comptonization of seed disc photons by a warm ( keV) and
optically thick () corona, mostly contributing to the soft X-rays;
(c) Comptonization by a standard hot ( keV) and
optically thin () corona, responsible for the primary X-ray
continuum; and (d) reflection from the mid/outer part of the disc. The two
coronae are suggested to be rather compact, with R. Our SED analysis implies that Ton S180 accretes
at super-Eddington rates. This is a key condition for the launch of a wind,
marginal (i.e., 3.1 significance) evidence of which is indeed found in
the RGS spectrum.Comment: 20 pages, 12 figures. Accepted for publication MNRA
Search for Narrow Diphoton Resonances and for gamma-gamma+W/Z Signatures in p\bar p Collisions at sqrt(s)=1.8 TeV
We present results of searches for diphoton resonances produced both
inclusively and also in association with a vector boson (W or Z) using 100
pb^{-1} of p\bar p collisions using the CDF detector. We set upper limits on
the product of cross section times branching ratio for both p\bar
p\to\gamma\gamma + X and p\bar p\to\gamma\gamma + W/Z. Comparing the inclusive
production to the expectations from heavy sgoldstinos we derive limits on the
supersymmetry-breaking scale sqrt{F} in the TeV range, depending on the
sgoldstino mass and the choice of other parameters. Also, using a NLO
prediction for the associated production of a Higgs boson with a W or Z boson,
we set an upper limit on the branching ratio for H\to\gamma\gamma. Finally, we
set a lower limit on the mass of a `bosophilic' Higgs boson (e.g. one which
couples only to \gamma, W, and Z$ bosons with standard model couplings) of 82
GeV/c^2 at 95% confidence level.Comment: 30 pages, 11 figure
Measurement of the p\bar{p}\sqrt{s}$ = 1.8 TeV
We update the measurement of the top production cross section using the CDF
detector at the Fermilab Tevatron. This measurement uses decays to
the final states +jets and +jets. We search for quarks from
decays via secondary-vertex identification or the identification of
semileptonic decays of the and cascade quarks. The background to the
production is determined primarily through a Monte Carlo simulation.
However, we calibrate the simulation and evaluate its uncertainty using several
independent data samples. For a top mass of 175 , we measure
pb and pb using
the secondary vertex and the lepton tagging algorithms, respectively. Finally,
we combine these results with those from other decay channels and
obtain pb.Comment: The manuscript consists of 130 pages, 35 figures and 42 tables in
RevTex. The manuscript is submitted to Physical Review D. Fixed typo in
author lis
Measurement of the Strong Coupling Constant from Inclusive Jet Production at the Tevatron Collider
We report a measurement of the strong coupling constant, ,
extracted from inclusive jet production in collisions at
1800 GeV. The QCD prediction for the evolution of with
jet transverse energy is tested over the range 40<<450 GeV using
for the renormalization scale. The data show good agreement with QCD in
the region below 250 GeV. In the text we discuss the data-theory comparison in
the region from 250 to 450 GeV. The value of at the mass of the
boson averaged over the range 40<<250 GeV is found to be
. The associated theoretical uncertainties are mainly due to the choice
of renormalization scale (^{+6%}_{-4%}) and input parton distribution
functions (5%).Comment: 7 pages, 3 figures, using RevTeX. Submitted to Physical Review
Letter
Neural processing of criticism and positive comments from relatives in individuals with schizotypal personality traits
Objectives. High negative expressed emotion by family members towards schizophrenia patients increases the risk of subsequent relapse. The study aimed to determine whether individuals with high schizotypy (HS) and low schizotypy (LS) would differ in activation of brain areas involved in cognitive control when listening to relative criticism
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