304 research outputs found
SN 2015ba: A type IIP supernova with a long plateau
We present optical photometry and spectroscopy from about a week after
explosion to 272 d of an atypical Type IIP supernova, SN 2015ba, which
exploded in the edge-on galaxy IC 1029. SN 2015ba is a luminous event with an
absolute V-band magnitude of -17.10.2 mag at 50 d since explosion and has
a long plateau lasting for 123 d. The distance to the SN is estimated to
be 34.80.7 Mpc using the expanding photosphere and standard candle
methods. High-velocity H-Balmer components constant with time are observed in
the late-plateau phase spectra of SN 2015ba, which suggests a possible role of
circumstellar interaction at these phases. Both hydrodynamical and analytical
modelling suggest a massive progenitor of SN 2015ba with a pre-explosion mass
of 24-26 M. However, the nebular spectra of SN 2015ba exhibit
insignificant levels of oxygen, which is otherwise expected from a massive
progenitor. This might be suggestive of the non-monotonical link between O-core
masses and the zero-age main-sequence mass of pre-supernova stars and/or
uncertainties in the mixing scenario in the ejecta of supernovae.Comment: 42 pages, 7 pages Appendix, 20 figures, 10 tables, Accepted for
publication in MNRAS, 14-June-201
Urban stream microbial communities show resistance to pharmaceutical exposure
Residues of pharmaceuticals are increasingly detected in surface waters throughout the world. In four streams in Baltimore, Maryland, USA, we detected analgesics, stimulants, antihistamines, and antibiotics using passive organic samplers. We exposed biofilm communities in these streams to the common drugs caffeine, cimetidine, ciprofloxacin, and diphenhydramine. Respiration rates in the least urban stream were suppressed when exposed to these drugs, but biofilm functioning in the most urban stream was resistant to drug exposure. Exposure to the antibiotic ciprofloxacin altered bacterial community composition at all sites, with the greatest change occurring in the most urban stream. These results indicated that continuous exposure to drugs in urban streams may select for sub-populations of highly resistant bacteria that maintain community function in response to urban contaminants
Stream Microbial Communities Show Resistance to Pharmaceutical Exposure
Residues of pharmaceuticals are increasingly detected in surface waters throughout the world. In four streams in Baltimore, Maryland, USA, we detected analgesics, stimulants, antihistamines, and antibiotics using passive organic samplers. We exposed biofilm communities in these streams to the common drugs caffeine, cimetidine, ciprofloxacin, and diphenhydramine. Respiration rates in the least urban stream were suppressed when exposed to these drugs, but biofilm functioning in the most urban stream was resistant to drug exposure. Exposure to the antibiotic ciprofloxacin altered bacterial community composition at all sites, with the greatest change occurring in the most urban stream. These results indicated that continuous exposure to drugs in urban streams may select for sub‐populations of highly resistant bacteria that maintain community function in response to urban contaminants
SN 2015as: A low luminosity Type IIb supernova without an early light curve peak
We present results of the photometric (from 3 to 509 days past explosion) and
spectroscopic (up to 230 days past explosion) monitoring campaign of the
He-rich Type IIb supernova (SN) 2015as. The {\it (B-V)} colour evolution of SN
2015as closely resemble those of SN 2008ax, suggesting that SN 2015as belongs
to the SN IIb subgroup that does not show the early, short-duration photometric
peak. The light curve of SN 2015as reaches the -band maximum about 22 days
after the explosion, at an absolute magnitude of -16.82 0.18 mag. At
75 days after the explosion, its spectrum transitions from that of a SN
II to a SN Ib. P~Cygni features due to He I lines appear at around 30 days
after explosion, indicating that the progenitor of SN 2015as was partially
stripped. For SN~2015as, we estimate a Ni mass of 0.08
M and ejecta mass of 1.1--2.2 M, which are similar to the
values inferred for SN 2008ax. The quasi bolometric analytical light curve
modelling suggests that the progenitor of SN 2015as has a modest mass (
0.1 M), a nearly-compact ( 0.0510 cm) H envelope
on top of a dense, compact ( 210 cm) and a more massive
( 1.2 M) He core. The analysis of the nebular phase spectra
indicates that 0.44 M of O is ejected in the explosion. The
intensity ratio of the [Ca II]/[O I] nebular lines favours either a main
sequence progenitor mass of 15 M or a Wolf Rayet star of 20
M.Comment: 23 pages, 18 figures, 10 tables, Accepted for publication in MNRAS,
16 February, 201
The optical properties of three type II supernovae: 2014cx, 2014cy and 2015cz
We present the photometric and spectroscopic analysis of three Type II SNe:
2014cx, 2014cy and 2015cz. SN 2014cx is a conventional Type IIP with a shallow
slope (0.2 mag/50d) and an atypical short plateau (86 d). SNe 2014cy and
2015cz show relatively large decline rates (0.88 and 1.64 mag/50d,
respectively) at early times before settling to the plateau phase, unlike the
canonical Type IIP/L SN light curves. All of them are normal luminosity SN II
with an absolute magnitude at mid-plateau of
M=16.60.4,
M=16.50.2 and
M=17.40.3. A relatively broad range of
Ni masses is ejected in these explosions (0.027-0.070 M). The
spectra show the classical evolution of Type II SNe, dominated by a blue
continuum with broad H lines at early phases and narrower metal lines with P
Cygni profiles during the plateau. High-velocity H I features are identified in
the plateau spectra of SN 2014cx at 11600 km s, possibly a sign of
ejecta-circumstellar interaction. The spectra of SN 2014cy exhibit strong
absorption profile of H I similar to normal luminosity events whereas strong
metal lines akin to sub-luminous SNe. The analytical modelling of the
bolometric light curve of the three events yields similar radii for the three
objects within errors (478, 507 and 608 R for SNe 2014cx, 2014cy and
2015cz, respectively) and a range of ejecta masses (15.0, 22.2 and 18.7
M for SNe 2014cx, 2014cy and 2015cz), and a modest range of explosion
energies (3.3 - 6.0 foe where 1 foe = 10 erg).Comment: 20 pages, 23 Figures, 3 figures in appendix, accepted for publication
in MNRA
Clinical Spectrum and Management of Diabetic Ketoacidosis: Experience in A Tertiary Care Hospital
Abstract Background: Diabetic ketoacidosis (DKA) is an acute metabolic complication of diabetes mellitus (DM). It may be the presenting feature in type 1 DM, but more commonly it complicates previously diagnosed diabetic patients, both type 1 and type 2. If not recognized early and treated in a judicious way the outcome is often fatal
Discovery and Rapid Follow-up Observations of the Unusual Type II SN 2018ivc in NGC 1068
We present the discovery and high-cadence follow-up observations of SN 2018ivc, an unusual SNe II that
exploded in NGC 1068 (D = 10.1 Mpc). The light curve of SN 2018ivc declines piecewise-linearly, changing
slope frequently, with four clear slope changes in the first 30 days of evolution. This rapidly changing light
curve indicates that interaction between the circumstellar material and ejecta plays a significant role in the
evolution. Circumstellar interaction is further supported by a strong X-ray detection. The spectra are rapidly
evolving and dominated by hydrogen, helium, and calcium emission lines. We identify a rare high-velocity
emission-line feature blueshifted at ∼7800 - km s 1 (in Hα, Hβ, Pβ, Pγ, He I, and Ca II), which is visible from
day 18 until at least day 78 and could be evidence of an asymmetric progenitor or explosion. From the overall
similarity between SN 2018ivc and SN 1996al, the Hα equivalent width of its parent H II region, and
constraints from pre-explosion archival Hubble Space Telescope images, we find that the progenitor of
SN 2018ivc could be as massive as 52 M but is more likely <12 M. SN 2018ivc demonstrates the importance
of the early discovery and rapid follow-up observations of nearby supernovae to study the physics and
progenitors of these cosmic explosions
Non-Hodgkin lymphoma response evaluation with MRI texture classification
<p>Abstract</p> <p>Background</p> <p>To show magnetic resonance imaging (MRI) texture appearance change in non-Hodgkin lymphoma (NHL) during treatment with response controlled by quantitative volume analysis.</p> <p>Methods</p> <p>A total of 19 patients having NHL with an evaluable lymphoma lesion were scanned at three imaging timepoints with 1.5T device during clinical treatment evaluation. Texture characteristics of images were analyzed and classified with MaZda application and statistical tests.</p> <p>Results</p> <p>NHL tissue MRI texture imaged before treatment and under chemotherapy was classified within several subgroups, showing best discrimination with 96% correct classification in non-linear discriminant analysis of T2-weighted images.</p> <p>Texture parameters of MRI data were successfully tested with statistical tests to assess the impact of the separability of the parameters in evaluating chemotherapy response in lymphoma tissue.</p> <p>Conclusion</p> <p>Texture characteristics of MRI data were classified successfully; this proved texture analysis to be potential quantitative means of representing lymphoma tissue changes during chemotherapy response monitoring.</p
Texture analysis of MR images of patients with Mild Traumatic Brain Injury
<p>Abstract</p> <p>Background</p> <p>Our objective was to study the effect of trauma on texture features in cerebral tissue in mild traumatic brain injury (MTBI). Our hypothesis was that a mild trauma may cause microstructural changes, which are not necessarily perceptible by visual inspection but could be detected with texture analysis (TA).</p> <p>Methods</p> <p>We imaged 42 MTBI patients by using 1.5 T MRI within three weeks of onset of trauma. TA was performed on the area of mesencephalon, cerebral white matter at the levels of mesencephalon, corona radiata and centrum semiovale and in different segments of corpus callosum (CC) which have been found to be sensitive to damage. The same procedure was carried out on a control group of ten healthy volunteers. Patients' TA data was compared with the TA results of the control group comparing the amount of statistically significantly differing TA parameters between the left and right sides of the cerebral tissue and comparing the most discriminative parameters.</p> <p>Results</p> <p>There were statistically significant differences especially in several co-occurrence and run-length matrix based parameters between left and right side in the area of mesencephalon, in cerebral white matter at the level of corona radiata and in the segments of CC in patients. Considerably less difference was observed in the healthy controls.</p> <p>Conclusions</p> <p>TA revealed significant changes in texture parameters of cerebral tissue between hemispheres and CC segments in TBI patients. TA may serve as a novel additional tool for detecting the conventionally invisible changes in cerebral tissue in MTBI and help the clinicians to make an early diagnosis.</p
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