17,514 research outputs found
Transient Relativistically-Shifted Lines as a Probe of Black Hole Systems
X-ray spectra of Seyfert galaxies have revealed a new type of X-ray spectral
feature, one which appears to offer important new insight into the black hole
system. XMM/Chandra revealed several narrow emission lines redward of Fe Kalpha
in NGC 3516. Since that discovery the phenomenon has been observed in other
Seyfert galaxies, e.g. NGC 7314 and ESO 198-G24. We present new evidence for a
redshifted Fe line in XMM spectra of Mrk 766. These data reveal the first
evidence for a significant shift in the energy of such a line, occurring over a
few tens of kiloseconds. This shift may be interpreted as deceleration of an
ejected blob of gas traveling close to the escape velocity.Comment: 13 pages, 5 figures (4 color) accepted by Ap
Extended Infusions of Meropenem for Febrile Neutropenia
Background: Neutropenic fever is an oncologic emergency that requires quick intervention with anti-pseudomonal beta-lactam antibiotics, such as meropenem. Previous literature suggests that extended infusions of beta-lactam antibiotics may improve clinical outcomes. To date, there are 3 prior studies utilizing an extended infusion beta-lactam in this population; however, there is only one previous study investigating the use of extended infusion meropenem in patients with febrile neutropenia.
Objective: To describe the outcomes of eight patients receiving extended infusions of meropenem for the treatment of febrile neutropenia.
Methods: A retrospective chart review was completed including adult patients admitted to a community teaching hospital who received extended infusions of meropenem for febrile neutropenia.
Results: In this descriptive study, no patients receiving extended infusions of meropenem failed treatment, were readmitted for an infectious issue within 30 days, or endured inpatient mortality. Additionally, all eight patients defervesced within 48 hours, and four patients had a microbiologically documented infection. One patient incurred Clostridium difficile on day 2 of meropenem therapy.
Conclusions: Extended infusions of meropenem may be effective in the treatment of febrile neutropenia. Future studies comparing extended infusions to intermittent infusions of meropenem for febrile neutropenia are warranted
Barefoot running improves economy at high intensities and peak treadmill velocity
Aim: Barefoot running can improve running economy (RE) compared to shod running at low exercise intensities, but data is lacking for the higher intensities typical during many distance running competitions. The influence of barefoot running on the velocity at maximal oxygen uptake (vVO2max) and peak incremental treadmill test velocity (vmax) is unknown. The present study tested the hypotheses that barefoot running would improve RE, vVO2max and vmax relative to shod running.
Methods: Using a balanced within-subject repeated measures design, eight male runners (aged 23.1±4.5 years, height 1.80±0.06 m, mass 73.8±11.5 kg, VO2max 4.08±0.39 L·min-1) completed a familiarization followed by one barefoot and one shod treadmill running trial, 2-14 days apart. Trial sessions consisted of a 5 minute warm-up, 5 minute rest, followed by 4×4 minute stages, at speeds corresponding to ~67, 75, 84 and 91% shod VO2max respectively, separated by a 1 minute rest. After the 4th stage treadmill speed was incremented by 0.1 km·h-1 every 15 s until participants reached volitional exhaustion.
Results: RE was improved by 4.4±7.0% across intensities in the barefoot condition (P=0.040). The improvement in RE was related to removed shoe mass (r2=0.80, P=0.003) with an intercept at 0% improvement for RE at 0.520 kg total shoe mass. Both vVO2max (by 4.5±5.0%, P=0.048) and vmax (by 3.9±4.0%, P=0.030) also improved but VO2max was unchanged (p=0.747).
Conclusion: Barefoot running improves RE at high exercise intensities and increases vVO2max and vmax, but further research is required to clarify the influence of very light shoe weights on RE
In vitro assessment of antioxidant properties of cocoa extract in cosmetic formulations: comparison between analysis by emitted light (ABEL) and ORAC antioxidant capacity methods
X-ray spectral complexity in narrow-line Seyfert 1 galaxies
We present a systematic analysis of the X-ray spectral properties of a sample
of 22 ``narrow-line'' Seyfert 1 galaxies for which data are available from the
ASCA public archive. Many of these sources, which were selected on the basis of
their relatively narrow H-beta line width (FWHM <= 2000 km/s), show significant
spectral complexity in the X-ray band. Their measured hard power-law continua
have photon indices spanning the range 1.6 - 2.5 with a mean of 2.1, which is
only slightly steeper than the norm for ``broad-line'' Seyfert 1s. All but four
of the sources exhibit a soft excess, which can be modelled as blackbody
emission (T_{bb} ~ 100 - 300 eV) superposed on the underlying power-law. This
soft component is often so strong that, even in the relatively hard bandpass of
ASCA, it contains a significant fraction, if not the bulk, of the X-ray
luminosity, apparently ruling out models in which the soft excess is produced
entirely through reprocessing of the hard continuum.
Most notably, 6 of the 22 objects show evidence for a broad absorption
feature centred in the energy range 1.1 - 1.4 keV, which could be the signature
of resonance absorption in highly ionized material. A further 3 sources exhibit
``warm absorption'' edges in the 0.7 - 0.9 keV bandpass. Remarkably, all 9
``absorbed'' sources have H-beta line widths below 1000 km/s, which is less
than the median value for the sample taken as a whole. This tendency for very
narrow line widths to correlate with the presence of ionized absorption
features in the soft X-ray spectra of NLS1s, if confirmed in larger samples,
may provide a further clue in the puzzle of active galactic nuclei.Comment: 13 pages, 5 figures, accepted for publication in MNRA
The introduction of a ward-based medical team system within a General and Emergency Medical Directorate
Evidence for a circum-nuclear and ionised absorber in the X-ray obscured BroadLine Radio Galaxy 3C 445
Here we present the results of a Suzaku observation of the Broad Line Radio
Galaxy 3C 445. We confirm the results obtained with the previous X-ray
observations which unveiled the presence of several soft X-ray emission lines
and an overall X-ray emission which strongly resembles a typical Seyfert 2
despite of the optical classification as an unobscured AGN. The broad band
spectrum allowed us to measure for the first time the amount of reflection
(R~0.9) which together with the relatively strong neutral Fe Kalpha emission
line (EW ~ 100 eV) strongly supports a scenario where a Compton-thick mirror is
present. The primary X-ray continuum is strongly obscured by an absorber with a
column density of NH =2-3 x10^{23} cm^{-2}. Two possible scenarios are proposed
for the absorber: a neutral partial covering or a mildly ionised absorber with
an ionisation parameter log\xi ~ 1.0 erg cm s^{-1}. A comparison with the past
and more recent X-ray observations of 3C 445 performed with XMM-Newton and
Chandra is presented, which provided tentative evidence that the ionised and
outflowing absorber varied. We argue that the absorber is probably associated
with an equatorial disk-wind located within the parsec scale molecular torus.Comment: Accepted by MNRAS; 13 pages, 6 figures, 4 table
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