164 research outputs found
Properties of the Young Milky Way Globular Cluster Whiting 1 from Near-Infrared Photometry
Whiting 1 is a member of the fast-growing group of young globular clusters in
the Milky Way halo. Preliminary estimates of its fundamental parameters have
been provided using optical photometry and low resolution spectroscopy. In an
attempt to strengthen our knowledge of Whiting 1, in this study we employ a
complementary approach. Isochrone fitting method was applied on the
Near-Infrared Color-Magnitude Diagram and yields an age t=5.70.3 Gyr,
metallicity =0.0060.001 ([Fe/H]=0.50.1) and distance modulus
=17.480.10. Our results confirm that Whiting 1 is a young and
moderately metal-rich globular cluster. It is one of the youngest from the Sgr
dSph. We fitted an Elson, Fall and Freeman (EFF) profile to the near-infrared
number counts, and measured cluster core radius
=9.13.9. Two probable eclipsing
variables in the cluster were found from multi-epoch band photometry.
Finally, an unknown galaxy cluster was identified on our vs.
color-magnitude diagram. It has a redshift z1, and it is located at about
1 from the center of Whiting 1 at , ,
contaminating the cluster photometry.Comment: Accepted for publication in MNRAS, 6 pages, 8 figure
Intranight variability of 3C 454.3 during its 2010 November outburst
Context. 3C 454.3 is a very active flat spectrum radio quasar (blazar) that
has undergone a recent outburst in all observed bands, including the optical.
Aims. In this work we explore the short-term optical variability of 3C 454.3
during its outburst by searching for time delays between different optical
bands. Finding one would be important for understanding the evolution of the
spectrum of the relativistic electrons, which generate the synchrotron jet
emission.
Methods. We performed photometric monitoring of the object by repeating
exposures in different optical bands (BVRI). Occasionally, different telescopes
were used to monitor the object in the same band to verify the reliability of
the smallest variations we observed.
Results. Except on one occasion, where we found indications of a lag of the
blue wavelengths behind the red ones, the results are inconclusive for most of
the other cases. There were either no structures in the light curves to be able
to search for patterns, or else different approaches led to different
conclusions.Comment: 4 pages, 4 figures. Accepted for publication in A&
On the Possible Application of Tubercles on Pumping Impeller to Decrease Hydraulic Resistance
This article is devoted to the biomimicry engineering approaches. The main idea of a tubercle technology and its advantage are presented. The conveniences of the usage of pumping impellers with tubercles in the main pipeline transport were formulated. It was also suggested to make profound learning of application of the tubercle technology in rotating devices
Optical monitoring of the z=4.40 quasar Q 2203+292
We report Cousins R-band monitoring of the high-redshift (z=4.40) radio quiet
quasar Q 2203+292 from May 1999 to October 2007. The quasar shows maximum
peak-to-peak light curve amplitude of ~0.3 mag during the time of our
monitoring, and ~0.9 mag when combined with older literature data. The rms of a
fit to the light curve with a constant is 0.08 mag and 0.2 mag, respectively.
The detected changes are at ~3-sigma level. The quasar was in a stable state
during the recent years and it might have undergone a brightening event in the
past. The structure function analysis concluded that the object shows
variability properties similar to those of the lower redshift quasars. We set a
lower limit to the Q 2203+292 broad line region mass of 0.3-0.4 M_odot.
Narrow-band imaging search for redshifted Ly_alpha from other emission line
objects at the same redshift shows no emission line objects in the quasar
vicinity.Comment: 9 pages, 8 figures, accepted for publication in MNRA
SURGICAL VERSUS CONSERVATIVE TREATMENT OF SPONTANEOUS INTRACEREBRAL HEMORRHAGE
Background: Spontaneous intracerebral hemorrhage (sICH) causes severe disability and high mortality. Today it is still an unresolved medical problem. The choice of optimal management - surgical or conservative, remains a difficult and controversial one. Early evacuation may restrict hematoma expansion and limit the secondary brain damage, improving the outcome for the patient.
Objective: To compare the effectiveness of surgical to conservative treatment of sICH.
Material and Methods: We examined 94 patients with sICH admitted to the Neurology Clinic within 24 hours of onset. Forty-seven patients underwent surgical evacuation and the remaining 47 received conservative medical therapy. Neurological deficit and clinical outcome were assessed by the Glasgow Coma Scale (GCS), National Institutes of Health Stroke Scale (NIHSS) and Glasgow Outcome Scale (GOS). Each patient was assessed on two occasions, the first on admission and the second after one month. The statistical analysis was performed with the Statistical Package for Social Sciences, version 13.0 (SPSS).
Results: Neurological deficit, hematoma volume and location displayed a correlation with GOS in the conservative group (p>0.05), while no statistical significance between GOS and hematoma volume in the surgical group (p12 had a better final GOS relative to conservatively treated ones. There was no statistically significant difference in GOS on the 30thday of treatment for both groups. The mortality of 4.3% was significantly lower in the surgical group (p<0.05).
Conclusion: Early surgery for sICH might be a safe and effective treatment, especially for large hematomas (>60cc) in male patients with progressive impairment of consciousness
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