2,476 research outputs found
Photometric and proper motion study of neglected open cluster NGC 2215
Optical UBVRI photometric measurements using the Faulkes Telescope North were
taken in early 2011 and combined with 2MASS JHK and WISE infrared
photometry as well as UCAC4 proper motion data in order to estimate the main
parameters of the galactic open cluster NGC 2215 of which large uncertainty
exists in the current literature. Fitting a King model we estimate a core
radius of 1.120.04 (0.240.01pc) and a limiting radius of
0.5 (0.940.11pc) for the cluster. The results of isochrone
fits indicates an age of with a distance of
pc, a metallicity of dex and a reddening of
. A proportion of the work in this study was undertaken by
Australian and Canadian upper secondary school students involved in the Space
to Grow astronomy education project, and is the first scientific publication to
have utilized our star cluster photometry curriculum materials.Comment: 10 pages, 9 Figures, 3 Table
Coherently Dedispersed Polarimetry of Millisecond Pulsars
We present a large sample of high-precision, coherently-dedispersed
polarization profiles of millisecond pulsars (MSPs) at frequencies between 410
and 1414 MHz. These data include the first polarimetric observations of several
of the pulsars, and the first low-frequency polarization profiles for others.
Our observations support previous suggestions that the pulse shapes and
polarimetry of MSPs are more complex than those of their slower relatives. An
immediate conclusion is that polarimetry-based classification schemes proposed
for young pulsars are of only limited use when applied to millisecond pulsars.Comment: 28 pages, 10 figures. Text matches version that appeared in ApJS.
Full paper with high-resolution figures available at
ftp://ftp.jb.man.ac.uk/pub/psr/papers/msppolpton.ps.g
Experimental study of digital image processing techniques for LANDSAT data
The author has identified the following significant results. Results are reported for: (1) subscene registration, (2) full scene rectification and registration, (3) resampling techniques, (4) and ground control point (GCP) extraction. Subscenes (354 pixels x 234 lines) were registered to approximately 1/4 pixel accuracy and evaluated by change detection imagery for three cases: (1) bulk data registration, (2) precision correction of a reference subscene using GCP data, and (3) independently precision processed subscenes. Full scene rectification and registration results were evaluated by using a correlation technique to measure registration errors of 0.3 pixel rms thoughout the full scene. Resampling evaluations of nearest neighbor and TRW cubic convolution processed data included change detection imagery and feature classification. Resampled data were also evaluated for an MSS scene containing specular solar reflections
Ethnicity-specific epigenetic variation in naïve CD4+ T cells and the susceptibility to autoimmunity
Abstract
Background
Genetic and epigenetic variability contributes to the susceptibility and pathogenesis of autoimmune diseases. T cells play an important role in several autoimmune conditions, including lupus, which is more common and more severe in people of African descent. To investigate inherent epigenetic differences in T cells between ethnicities, we characterized genome-wide DNA methylation patterns in naïve CD4+ T cells in healthy African-Americans and European-Americans, and then confirmed our findings in lupus patients.
Results
Impressive ethnicity-specific clustering of DNA methylation profiling in naïve CD4+ T cells was revealed. Hypomethylated loci in healthy African-Americans were significantly enriched in pro-apoptotic and pro-inflammatory genes. We also found hypomethylated genes in African-Americans to be disproportionately related to autoimmune diseases including lupus. We then confirmed that these genes, such as IL32, CD226, CDKN1A, and PTPRN2 were similarly hypomethylated in lupus patients of African-American compared to European-American descent. Using patch DNA methylation and luciferase reporter constructs, we showed that methylation of the IL32 promoter region reduces gene expression in vitro. Importantly, bisulfite DNA sequencing demonstrated that cis-acting genetic variants within and directly disrupting CpG sites account for some ethnicity-specific variability in DNA methylation.
Conclusion
Ethnicity-specific inherited epigenetic susceptibility loci in CD4+ T cells provide clues to explain differences in the susceptibility to autoimmunity and possibly other T cell-related diseases between populations.http://deepblue.lib.umich.edu/bitstream/2027.42/116042/1/13072_2015_Article_37.pd
Polarimetric Properties of the Crab Pulsar between 1.4 and 8.4 GHz
New polarimetric observations of the Crab pulsar at frequencies between 1.4
and 8.4 GHz are presented. Additional pulse components discovered in earlier
observations (Moffett & Hankins 1996, astro-ph/9604163) are found to have high
levels of linear polarization, even at 8.4 GHz. No abrupt sweeps in position
angle are found within pulse components; however, the position angle and
rotational phase of the interpulse do change dramatically between 1.4 and 4.9
GHz. The multi-frequency profile morphology and polarization properties
indicate a non-standard origin of the emission. Several emission geometries are
discussed, but the one favored locates sites of emission both near the pulsar
surface and in the outer magnetosphere.Comment: 20 pages, 7 postscript figures, uses aaspp4 Latex style. To appear in
Volume 522 of The Astrophysical Journa
Return to Sport after Surgical Treatment of Lisfranc Injuries in Athletes: A Retrospective Case Series
Introduction
A Lisfranc injury can be a devastating injury in athletes,and if inadequately treated, may lead to chronic pain and lossof function. The purpose of this study was to determine the rate andtime until return to sport after surgical fixation for a ligamentous Lisfrancinjury. We hypothesized that open reduction and screw fixationof a ligamentous Lisfranc injury can be a successful treatment in theathletic population and allow patients to return to sport at close totheir preinjury level of play.
Methods
All patients who were analyzed underwent repair of aligamentous Lisfranc injury with open reduction and screw fixationby a single surgeon, were between 18 - 40 years old at time of theirfinal follow up, and were identified as being an athlete (either recreationalor competitive). Eligible patients were given a questionnairethat included if they were able to return to sport, time until return tosport, subjective percentage of pre-injury level of play, current pain(0 - 10), and complications.
Results
Eleven patients were identified as athletes. Ten (91%) wereavailable for follow-up with a mean of 36.5 months (range, 14 - 60).The average age was 25.4 years (range, 15 - 37) at time of surgery.Eighty percent (8/10) were able to return to sport. The average timeuntil return to sport was 29.4 weeks (range, 22 - 52) with an averagesubjective value of their pre-injury level of play of 87% (range, 70 -100%). However, 67% (6/9) of the athletes had occasional pain withsport with an average pain level of 2.1 (range, 0 - 5). Two patientshad complications, a superficial infection and a deep vein thrombosis.
Conclusion
Most athletes were able to return to sport after undergoingopen reduction and internal fixation of a ligamentous Lisfrancinjury by less than 30 weeks post-surgery with a subjective value of87% of their previous function. However, the majority of the patientsalso experienced some residual pain with their respective sport.These findings suggested that athletes with a ligamentous Lisfrancinjury can have reliably good outcomes with operative repair
3C 286: a bright, compact, stable, and highly polarized calibrator for millimeter-wavelength observations
(Context.) A number of millimeter and submillimeter facilities with linear
polarization observing capabilities have started operating during last years.
These facilities, as well as other previous millimeter telescopes and
interferometers, require bright and stable linear polarization calibrators to
calibrate new instruments and to monitor their instrumental polarization. The
current limited number of adequate calibrators implies difficulties in the
acquisition of these calibration observations. (Aims.) Looking for additional
linear polarization calibrators in the millimeter spectral range, in mid-2006
we started monitoring 3C 286, a standard and highly stable polarization
calibrator for radio observations. (Methods.) Here we present the 3 and 1 mm
monitoring observations obtained between September 2006 and January 2012 with
the XPOL polarimeter on the IRAM 30 m Millimeter Telescope. (Results.) Our
observations show that 3C 286 is a bright source of constant total flux with 3
mm flux density S_3mm = (0.91 \pm 0.02) Jy. The 3mm linear polarization degree
(p_3mm =[13.5\pm0.3]%) and polarization angle (chi_3mm
=[37.3\pm0.8]deg.,expressed in the equatorial coordinate system) are also
constant during the time span of our observations. Although with poorer time
sampling and signal-to-noise ratio, our 1 mm observations of 3C 286 are also
reproduced by a constant source of 1 mm flux density (S_1mm = [0.30 \pm 0.03]
Jy), polarization fraction (p_1mm = [14.4 \pm 1.8] %), and polarization angle
(chi_1mm = [33.1 \pm 5.7]deg.). (Conclusions.) This, together with the
previously known compact structure of 3C 286 -extended by ~3.5" in the sky-
allow us to propose 3C 286 as a new calibrator for both single dish and
interferometric polarization observations at 3 mm, and possibly at shorter
wavelengths.Comment: Accepted for publication in A&A. 7 pages, 4 figures, 8 tables.
Updated data sets with regard to previous version. New discussion about multi
frequency properties of the source. Section 3.3, Figures 3 and 4, and Tables
7 and 8 are ne
A Pilot Study Assessing the Effects of Goal Management Training on Cognitive Functions among Individuals with Major Depressive Disorder and the Effect of Post-Traumatic Symptoms on Response to Intervention
Recent meta-analyses highlight alterations in cognitive functioning among individuals with major depressive disorder (MDD), with performance deficits observed across multiple cognitive domains including executive functioning, memory, and attention. Moreover, impaired concentration is a formal diagnostic criterion for a major depressive episode. Notably, cognitive impairment is reported frequently in MDD and is associated with poor treatment response. Despite this knowledge, research examining the effectiveness of top-down, adjunctive treatments for cognitive dysfunction in MDD remains in its infancy. The primary aim of the present study was to perform a pilot investigation of the implementation of a standardized cognitive remediation program, Goal Management Training (GMT), among individuals with a primary diagnosis of MDD. A secondary aim was to explore how comorbid symptoms of post-traumatic stress disorder (PTSD) among those MDD patients exposed to trauma may affect treatment response. A final sample of thirty individuals were randomized to either participate in the nine-week GMT program (active group; n = 16) or to complete a nine-week waiting period (waitlist control; n = 14). One participant was excluded from the GMT group analysis following study completion due to meeting an exclusion criteria. In total, 60% of the individuals allocated to the GMT program were trauma exposed (n = 9). Groups were assessed at baseline, post-treatment, and at three-month follow-up. The assessment comprised neuropsychological tasks assessing a variety of cognitive domains, subjective measures of functioning and symptom severity, as well as a clinical interview to establish a primary diagnosis of MDD. Significant gains in processing speed, attention/concentration, and response inhibition were observed for the participants in the GMT condition relative to participants in the waitlist control condition. Individuals in the GMT condition also reported improvements in subjective cognitive functioning from baseline to post-treatment. Heightened PTSD symptom severity was associated with reduced response to treatment with respect to the domain of processing speed. The results of this pilot investigation highlight not only the potential utility of GMT as an augmentative treatment in MDD, but also highlight the contribution of comorbid symptoms of PTSD to diminished treatment response among trauma-exposed individuals with MDD. The study is limited primarily by its small pilot sample and the absence of a program evaluation component to gauge participant opinions and feedback of the treatment protocol
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