356 research outputs found
Extending the Reach of the Library with a Mobile Reference Program
Creating a mobile reference service can improve library support for research and scholarship, cultivate and strengthen relationships with other campus departments, and enhance marketing and delivery of library resources and services. In this session, the University of St. Thomas will share their experience in developing a mobile reference program - i.e. roving librarian or librarian with a laptop. Librarians have visited public areas on campus to provide research assistance and the program has even evolved into a partnership with the campus career development center providing company research for students doing on-campus interviews. We’ll share how the program was developed, the tools used to provide this service, lessons learned and the reactions of our campus community
Sequential and Spontaneous Star Formation Around the Mid-Infrared Halo HII Region KR 140
We use 2MASS and MSX infrared observations, along with new molecular line
(CO) observations, to examine the distribution of young stellar objects (YSOs)
in the molecular cloud surrounding the halo HII region KR 140 in order to
determine if the ongoing star-formation activity in this region is dominated by
sequential star formation within the photodissociation region (PDR) surrounding
the HII region. We find that KR 140 has an extensive population of YSOs that
have spontaneously formed due to processes not related to the expansion of the
HII region. Much of the YSO population in the molecular cloud is concentrated
along a dense filamentary molecular structure, traced by C18O, that has not
been erased by the formation of the exciting O star. Some of the previously
observed submillimetre clumps surrounding the HII region are shown to be sites
of recent intermediate and low-mass star formation while other massive starless
clumps clearly associated with the PDR may be the next sites of sequential star
formation.Comment: Accepted for publication in MNRAS, 8 pages, 10 figure
Evaluating blood-brain barrier permeability in delayed cerebral infarction after aneurysmal subarachnoid hemorrhage
BACKGROUND AND PURPOSE: Patients with SAH are at increased risk of delayed infarction. Early detection and treatment of delayed infarction remain challenging. We assessed blood-brain barrier permeability, measured as permeability surface area product, by using CTP in patients with SAH with delayed infarction. MATERIALS AND METHODS: We performed a retrospective study of patients with SAH with delayed infarction on follow-up NCCT. CTP was performed before the development of delayed infarction. CTP data were postprocessed into permeability surface area product, CBF, and MTT maps. Coregistration was performed to align the infarcted region on the follow-up NCCT with the corresponding location on the CTP maps obtained before infarction. Permeability surface area product, CBF, and MTT values were then obtained in the location of the subsequent infarction. The contralateral noninfarcted region was compared with the affected side in each patient. Wilcoxon signed rank tests were performed to determine statistical significance. Clinical data were collected at the time of CTP and at the time of follow-up NCCT. RESULTS: Twenty-one patients with SAH were included in the study. There was a statistically significant increase in permeability surface area product in the regions of subsequent infarction compared with the contralateral control regions (P \u3c .0001). However, CBF and MTT values were not significantly different in these 2 regions. Subsequent follow-up NCCT demonstrated new delayed infarction in all 21 patients, at which time 38% of patients had new focal neurologic deficits. CONCLUSIONS: Our study reveals a statistically significant increase in permeability surface area product preceding delayed infarction in patients with SAH. Further investigation of early permeability changes in SAH may provide new insights into the prediction of delayed infarction
The HII Region KR 140: Spontaneous Formation of a High Mass Star
We have used a multiwavelength data set from the Canadian Galactic Plane
Survey (CGPS) to study the Galactic HII region KR 140, both on the scale of the
nebula itself and in the context of the star forming activity in the nearby
W3/W4/W5 complex of molecular clouds and HII regions. From both radio and
infrared data we have found a covering factor of about 0.5 for KR 140 and we
interpret the nebula as a bowl-shaped region viewed close to face on.
Extinction measurements place the region on the near side of its parent
molecular cloud. The nebula is kept ionized by one O8.5 V(e) star, VES 735,
which is less than a few million years old. CO data show that VES 735 has
disrupted much of the original molecular cloud for which the estimated mass and
density are about 5000 and 100 cm, respectively. KR 140 is
isolated from the nearest star forming activity, in W3. Our data suggest that
KR 140 is an example of spontaneous (i.e., non-triggered) formation of,
unusually, a high mass star.Comment: 46 pages; includes 15 figures; accepted by the Ap
Imaging and spectroscopy of the faint remnant G 114.3+0.3
We present the first calibrated CCD images of the faint supernova remnant G
114.3+0.3 in the emission lines of [OII], [OIII], Halpha+[NII] and [SII]. The
deep low ionization CCD images reveal diffuse emission in the south and central
areas of the remnant. These are correlated with areas of intense radio
emission, while estimates of the [SII]/Halpha ratio suggest that the detected
emission originates from shock heated gas. In the medium ionization image of
[OIII] we discovered a thin filament in the south matching very well the outer
radio contours. This filament is not continuous over its total extent but shows
variations in the intensity, mainly in the south-west suggesting inhomogeneous
interstellar clouds. Deep long-slit spectra were also taken along the [OIII]
filament clearly identifying the observed emission as emission from shock
heated gas. The Halpha emission is a few times 10^(-17) erg s^(-1) cm^(-2)
arcsec^(-2), while the variations seen in the [OIII] flux suggest shock
velocities into the interstellar clouds around or below 100 km/s. The sulfur
line ratio approaches the low density limit implying electron densities less
than ~500 cm^(-3).Comment: 6 pages, 4 figures, accepted for publication in A&
Radio polarimetric imaging of the interstellar medium: magnetic field and diffuse ionized gas structure near the W3/W4/W5/HB3 complex
We have used polarimetric imaging to study the magneto-ionic medium of the
Galaxy, obtaining 1420 MHz images with an angular resolution of 1' over more
than 40 square-degrees of sky around the W3/W4/W5/HB3 HII region/SNR complex in
the Perseus Arm. Features detected in polarization angle are imposed on the
linearly polarized Galactic synchrotron background emission by Faraday rotation
arising in foreground ionized gas having an emission measure as low as 1
cm^{-6} pc. Several new remarkable phenomena have been identified, including:
mottled polarization arising from random fluctuations in a magneto-ionic screen
that we identify with a medium in the Perseus Arm, probably in the vicinity of
the HII regions themselves; depolarization arising from very high rotation
measures (several times 10^3 rad m^{-2}) and rotation measure gradients due to
the dense, turbulent environs of the HII regions; highly ordered features
spanning up to several degrees; and an extended influence of the HII regions
beyond the boundaries defined by earlier observations. In particular, the
effects of an extended, low-density ionized halo around the HII region W4 are
evident, probably an example of the extended HII envelopes postulated as the
origin of weak recombination-line emission detected from the Galactic ridge.
Our polarization observations can be understood if the uniform magnetic field
component in this envelope scales with the square-root of electron density and
is 20 microG at the edge of the depolarized region around W4, although this is
probably an over-estimate since the random field component will have a
significant effect.Comment: 18 pages, 8 figures (7 jpeg and 1 postscript), accepted for
publication in the Astrophysical Journa
A Sino-German 6 cm polarization survey of the Galactic plane II. The region from 129 degree to 230 degree longitude
Linearly polarized Galactic synchrotron emission provides valuable
information about the properties of the Galactic magnetic field and the
interstellar magneto-ionic medium, when Faraday rotation along the line of
sight is properly taken into account. We aim to survey the Galactic plane at 6
cm including linear polarization. At such a short wavelength Faraday rotation
effects are in general small and the Galactic magnetic field properties can be
probed to larger distances than at long wavelengths. The Urumqi 25-m telescope
is used for a sensitive 6 cm survey in total and polarized intensities. WMAP
K-band (22.8 GHz) polarization data are used to restore the absolute zero-level
of the Urumqi U and Q maps by extrapolation. Total intensity and polarization
maps are presented for a Galactic plane region of 129 degree < l < 230 degree
and |b| < 5 degree in the anti-centre with an angular resolution of 9'5 and an
average sensitivity of 0.6 mK and 0.4 mK Tb in total and polarized intensity,
respectively. We briefly discuss the properties of some extended Faraday
Screens detected in the 6 cm polarization maps. The Sino-German 6 cm
polarization survey provides new information about the properties of the
magnetic ISM. The survey also adds valuable information for discrete Galactic
objects and is in particular suited to detect extended Faraday Screens with
large rotation measures hosting strong regular magnetic fields.Comment: 17 pages, 20 figures, accepted by A&A. Resolutions of the figures
have been significantly reduced. For version with full resolution, see
http://159.226.88.6/zmtt/6cm/papers/gao.paper2.pd
Association between circulating exhausted CD4+ T cells with poor meningococcal C conjugate vaccine antibody response in HIV-infected children and adolescents
OBJECTIVES: To investigate the expression levels of surface markers of activation (CD38 and HLA-DR), inhibition (PD-1, TIGIT and CD57) and co-stimulation (CD28 and CD127) on CD4+ T cells of children/adolescents with vertical HIV infection (HI patients) and HIV-uninfected (HU) controls vaccinated with the meningococcal C conjugate vaccine (MCC). METHODS: HI patients (n=12), aged 8–17 years, were immunized with two MCC injections, while HU controls (n=9), aged 5.3–10.7 years, received a single MCC dose (as per national recommendation at the time of this study, a single MCC vaccine dose should be given for healthy children and youth aged 1–18 years). The HI patients were categorized according to the combined antiretroviral therapy (cART) treatment. Blood samples were obtained before vaccination, after priming, and after the administration of a booster dose of vaccine to determine the serum bactericidal antibody (SBA) titers and the expression levels of surface markers on CD4+ T cells by flow cytometry. The levels of serum cytokines, IL-4 and CXCL-13 were also measured using Luminex kits. RESULTS: The co-expression of the TIGIT-HLA-DR-CD38 molecules increased in the CD4+ T cells of HI patients/ no-cART who also showed a lower frequency of CD127+CD28+ CD4+ T cells than HI patients/cART and HU group subjects. There were significant negative correlations between the frequency of exhausted CD4+ T cells and the SBA response. IL-4 levels were higher in HI patients/cART and positively correlated with SBA titers but negatively associated with the expression of exhaustion markers. Moreover, the CXCL-13 levels were positively correlated with the exhausted CD4+ T cells. CONCLUSION: The results of our study suggest that the co-expression of exhaustion markers and/or loss of co-stimulatory molecules influence the SBA response in HI patients
Detection of Extended VHE Gamma Ray Emission from G106.3+2.7 with VERITAS
We report the detection of very-high-energy (VHE) gamma-ray emission from
supernova remnant (SNR) G106.3+2.7. Observations performed in 2008 with the
VERITAS atmospheric Cherenkov gamma-ray telescope resolve extended emission
overlapping the elongated radio SNR. The 7.3 sigma (pre-trials) detection has a
full angular extent of roughly 0.6deg by 0.4deg. Most notably, the centroid of
the VHE emission is centered near the peak of the coincident 12CO (J = 1-0)
emission, 0.4deg away from the pulsar PSR J2229+6114, situated at the northern
end of the SNR. Evidently the current-epoch particles from the pulsar wind
nebula are not participating in the gamma-ray production. The VHE energy
spectrum measured with VERITAS is well characterized by a power law dN/dE =
N_0(E/3 TeV)^{-G} with a differential index of G = 2.29 +/- 0.33stat +/-
0.30sys and a flux of N_0 = (1.15 +/- 0.27stat +/- 0.35sys)x 10^{-13} cm^{-2}
s^{-1} TeV^{-1}. The integral flux above 1 TeV corresponds to ~5 percent of the
steady Crab Nebula emission above the same energy. We describe the observations
and analysis of the object and briefly discuss the implications of the
detection in a multiwavelength context.Comment: 5 pages, 2 figure
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