696 research outputs found
Spectral and temporal properties of RX J0520.5-6932 (LXP 8.04) during a type-I outburst
We observed RX J0520.5-6932 in the X-rays and studied the optical light curve
of its counterpart to verify it as a Be/X-ray binary. We performed an
XMM-Newton anticipated target of opportunity observation in January 2013 during
an X-ray outburst of the source in order to search for pulsations and derive
its spectral properties. We monitored the source with Swift to follow the
evolution of the outburst and to look for further outbursts to verify the
regular pattern seen in the optical light curve with a period of ~24.4 d. The
XMM-Newton EPIC light curves show coherent X-ray pulsations with a period of
8.035331(15) s (1 sigma). The X-ray spectrum can be modelled by an absorbed
power law with photon index of ~0.8, an additional black-body component with
temperature of ~0.25 keV and an Fe K line. Phase-resolved X-ray spectroscopy
reveals that the spectrum varies with pulse phase. We confirm the
identification of the optical counterpart within the error circle of XMM-Newton
at an angular distance of ~0.8 arcsec, which is an O9Ve star with known Halpha
emission. By analyzing the combined data from three OGLE phases we derived an
optical period of 24.43 d.The X-ray pulsations and long-term variability, as
well as the properties of the optical counterpart, confirm that RX J0520.5-6932
is a Be/X-ray binary pulsar in the Large Magellanic Cloud. Based on the X-ray
monitoring of the source we conclude that the event in January 2013 was a
moderately bright type-I X-ray outburst, with a peak luminosity of 1.79e36
erg/s.Comment: 10 pages, 9 figures, accepted A&
Human pigmentation genes under environmental selection
Genome-wide association studies and comparative genomics have established major loci and specific polymorphisms affecting human skin, hair and eye color. Environmental changes have had an impact on selected pigmentation genes as populations have expanded into different regions of the globe
Infrared Spectroscopy of the Diffuse Ionized Halo of NGC 891
We present infrared spectroscopy from the Spitzer Space Telescope at one disk
position and two positions at a height of 1 kpc from the disk in the edge-on
spiral NGC 891, with the primary goal of studying halo ionization. Our main
result is that the [Ne III]/[Ne II] ratio, which provides a measure of the
hardness of the ionizing spectrum free from the major problems plaguing optical
line ratios, is enhanced in the extraplanar pointings relative to the disk
pointing. Using a 2D Monte Carlo-based photo-ionization code which accounts for
the effects of radiation field hardening, we find that this trend cannot be
reproduced by any plausible photo-ionization model, and that a secondary source
of ionization must therefore operate in gaseous halos. We also present the
first spectroscopic detections of extraplanar PAH features in an external
normal galaxy. If they are in an exponential layer, very rough emission
scale-heights of 330-530 pc are implied for the various features. Extinction
may be non-negligible in the midplane and reduce these scale-heights
significantly. There is little significant variation in the relative emission
from the various features between disk and extraplanar environment. Only the
17.4 micron feature is significantly enhanced in the extraplanar gas compared
to the other features, possibly indicating a preference for larger PAHs in the
halo.Comment: 35 pages in ApJ preprint format, 8 figures, accepted for publication
in ApJ. Minor change to Introduction to give appropriate credit to earlier,
related wor
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A randomised phase I study of etrolizumab (rhuMAb β7) in moderate to severe ulcerative colitis.
ObjectiveEtrolizumab (rhuMAb β7, anti-β7, PRO145223) is a humanised monoclonal antibody targeting the β7 subunit of the heterodimeric integrins α4β7 and αEβ7, which are implicated in leucocyte migration and retention in ulcerative colitis (UC). This randomised phase I study evaluated the safety and pharmacology of etrolizumab in patients with moderate to severe UC.DesignIn the single ascending dose (SAD) stage, etrolizumab (0.3, 1.0, 3.0, 10 mg/kg intravenous, 3.0 mg/kg subcutaneous (SC) or placebo) was administered 4:1 (n=25) in each cohort. In the multiple dose (MD) stage, new patients received monthly etrolizumab (0.5 mg/kg SC (n=4), 1.5 mg/kg SC (n=5), 3.0 mg/kg SC (n=4), 4.0 mg/kg intravenous (n=5)) or placebo (n=5). The pharmacokinetics was studied and Mayo Clinic Score evaluated at baseline, day 29 (SAD), and days 43 and 71 (MD).ResultsIn the SAD stage, there were no dose limiting toxicities, infusion or injection site reactions. Two impaired wound healing serious adverse events occurred in two patients receiving etrolizumab. In the MD stage, there were no dose limiting toxicities, and no infusion or injection site reactions. Headache was the most common adverse event, occurring more often in etrolizumab patients. Antietrolizumab antibodies were detected in two subjects. The duration of β7 receptor full occupancy was dose related. A clinical response was observed in 12/18 patients, and clinical remission in 3/18 patients treated with etrolizumab in the MD stage, compared with 4/5 and 1/5 placebo patients, respectively.ConclusionEtrolizumab is well tolerated in moderate to severe UC. Further investigation is warranted
Particle size dependent sinterability and magnetic properties of recycled HDDR Nd–Fe–B powders consolidated with spark plasma sintering
Insights into the mechanical properties of several triply periodic minimal surface lattice structures made by polymer additive manufacturing
Three-dimensional lattices have applications across a range of fields including structural lightweighting, impact absorption and biomedicine. In this work, lattices based on triply periodic minimal surfaces were produced by polymer additive manufacturing and examined with a combination of experimental and computational methods. This investigation elucidates their deformation mechanisms and provides numerical parameters crucial in establishing relationships between their geometries and mechanical performance. Three types of lattice were examined, with one, known as the primitive lattice, being found to have a relative elastic modulus over twice as large as those of the other two. The deformation process of the primitive lattice was also considerably different from those of the other two, exhibiting strut stretching and buckling, while the gyroid and diamond lattices deformed in a bending dominated manner. Finite element predictions of the stress distributions in the lattices under compressive loading agreed with experimental observations. These results can be used to create better informed lattice designs for a range of mechanical and biomedical applications
Frontiers in Pigment Cell and Melanoma Research
We identify emerging frontiers in clinical and basic research of melanocyte
biology and its associated biomedical disciplines. We describe challenges and
opportunities in clinical and basic research of normal and diseased melanocytes
that impact current approaches to research in melanoma and the dermatological
sciences. We focus on four themes: (1) clinical melanoma research, (2) basic
melanoma research, (3) clinical dermatology, and (4) basic pigment cell
research, with the goal of outlining current highlights, challenges, and
frontiers associated with pigmentation and melanocyte biology. Significantly,
this document encapsulates important advances in melanocyte and melanoma
research including emerging frontiers in melanoma immunotherapy, medical and
surgical oncology, dermatology, vitiligo, albinism, genomics and systems
biology, epidemiology, pigment biophysics and chemistry, and evolution
Using real-time data to test for political budget cycles
We use real‐time annual data on the fiscal balance, government current spending, current revenues and net capital outlays as published at a half yearly frequency in the OECD Economic Outlook for 25 OECD countries. For each fiscal year t we have a number of forecasts, a first release, and subsequent revisions. It turns out that revisions in the fiscal balance data are not affected by elections. However, we do find that governments spend more than reported before an election which provides support for moralhazard type of political budget cycle (PBC) models: through hidden efforts the incumbent tries to enhance his perceived competence. We also find that governments had higher current receipts than reported before an election, which is in line with adverse‐selection type of PBC models in which incumbents signal competence through expansionary fiscal policy before the elections
BRAF wild-type melanoma in situ arising in a BRAF V600E mutant dysplastic nevus
IMPORTANCE The BRAF V600E mutation accounts for the majority of BRAF mutations found in cutaneous melanoma and is also commonly found in nevi. We used dermoscopy-targeted sampling and a microbiopsy device coupled with DNA sequence analysis to highlight BRAF V600E heterogeneity within a multicomponent melanocytic proliferation. This sampling technique demonstrates the prospect of in vivo application in a clinical setting
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