258 research outputs found

    Particulate Matter Exposure Impairs Systemic Microvascular Endothelium-Dependent Dilation

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    Acute exposure to airborne pollutants, such as solid particulate matter (PM), increases the risk of cardiovascular dysfunction, but the mechanisms by which PM evokes systemic effects remain to be identified. The purpose of this study was to determine if pulmonary exposure to a PM surrogate, such as residual oil fly ash (ROFA), affects endothelium-dependent dilation in the systemic microcirculation. Rats were intratracheally instilled with ROFA at 0.1, 0.25, 1 or 2 mg/rat 24 hr before experimental measurements. Rats intratracheally instilled with saline or titanium dioxide (0.25 mg/rat) served as vehicle or particle control groups, respectively. In vivo microscopy of the spinotrapezius muscle was used to study systemic arteriolar dilator responses to the Ca(2+) ionophore A23187, administered by ejection via pressurized micropipette into the arteriolar lumen. We used analysis of bronchoalveolar lavage (BAL) samples to monitor identified pulmonary inflammation and damage. To determine if ROFA exposure affected arteriolar nitric oxide sensitivity, sodium nitroprusside was iontophoretically applied to arterioles of rats exposed to ROFA. In saline-treated rats, A23187 dilated arterioles up to 72 ± 7% of maximum. In ROFA- and TiO(2)-exposed rats, A23187-induced dilation was significantly attenuated. BAL fluid analysis revealed measurable pulmonary inflammation and damage after exposure to 1 and 2 mg ROFA (but not TiO(2) or < 1 mg ROFA), as evidenced by significantly higher polymorphonuclear leukocyte cell counts, enhanced BAL albumin levels, and increased lactate dehydrogenase activity in BAL fluid. The sensitivity of arteriolar smooth muscle to NO was similar in saline-treated and ROFA-exposed rats, suggesting that pulmonary exposure to ROFA affected endothelial rather than smooth muscle function. A significant increase in venular leukocyte adhesion and rolling was observed in ROFA-exposed rats, suggesting local inflammation at the systemic microvascular level. These results indicate that pulmonary PM exposure impairs systemic endothelium-dependent arteriolar dilation. Moreover, because rats exposed to < 1 mg ROFA or TiO(2) did not exhibit BAL signs of pulmonary damage or inflammation, it appears that PM exposure can impair systemic microvascular function independently of detectable pulmonary inflammation

    A SCUBA Scanmap of the HDF: Measuring the bright end of the sub-mm source counts

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    Using the 850 micron SCUBA camera on the JCMT and a scanning technique different from other sub-mm surveys, we have obtained a 125 square arcminute map centered on the Hubble Deep Field. The one-sigma sensitivity to point sources is roughly 3 mJy and thus our map probes the brighter end of the sub-mm source counts. We find 6 sources with a flux greater than about 12 mJy (>4 sigma) and, after a careful accounting of incompleteness and flux bias, estimate the integrated density of bright sources N(>12 mJy)= 164 (+77/-58) per square degree (68 per cent confidence bounds).Comment: 5 pages, 2 figures, Accepted for publication in MNRA

    Hadronic Event Shapes in BB Decay

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    We compute the differential momentum correlation function for hadrons produced in the decay of BB-mesons. This measure of hadronic event shapes tests the free bb-quark decay picture for nonleptonic and semileptonic decays of BB-mesons. Our results can also be applied to BsB_s and Λb\Lambda_b decay.Comment: 11 pages, 3 uuencoded figures included, uses harvmac and epsf, UTPT 93-28, CMU-HEP 93-24, CALT-68-190

    From terror to pride: Supporting faculty through a blended learning community of transformation during the COVID-19 pandemic

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    The COVID-19 pandemic and the shift to remote, blended, and online teaching and learning presented universities around the world with myriad challenges. This rapid shift into uncharted territory, however, also created an opportunity for faculty developers to lead exploration of new pedagogies, challenging teaching assumptions. In this article, we share the story of how a center for teaching and learning led the shift to remote and blended learning through a community of transformation (Kezar et al., 2018). We share results from a survey of faculty following multiple professional development opportunities and explore themes that emerged from interviews with six instructors representing a range of disciplines and experience in remote and blended teaching. We conclude by offering our design elements to consider when pursuing faculty development as a potentially transformative learning experience (Mezirow, 1991)

    New features in the simulation of neutrino oscillation experiments with GLoBES 3.0

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    We present Version 3.0 of the GLoBES (``General Long Baseline Experiment Simulator'') software, which is a simulation tool for short- and long-baseline neutrino oscillation experiments. As a new feature, GLoBES 3.0 allows for user-defined systematical errors, which can also be used to simulate experiments with multiple discrete sources and detectors. In addition, the combination with external information, such as from different experiment classes, is simplified. As far as the probability calculation is concerned, GLoBES now provides an interface for the inclusion of non-standard physics without re-compilation of the software. The set of experiment prototypes coming with GLoBES has been updated. For example, built-in fluxes are now provided for the simulation of beta beams.Comment: 14 pages, 3 figures, 1 table. Definition of chi2 refined, version to appear in Comput. Phys. Commun. GLoBES software available at http://www.mpi-hd.mpg.de/lin/globes

    Leptonic contribution to the bulk viscosity of nuclear matter

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    For beta-equilibrated nuclear matter we estimate the contribution to the bulk viscosity from purely leptonic processes, namely the conversion of electrons to and from muons. For oscillation frequencies in the kiloHertz range, we find that this process provides the dominant contribution to the bulk viscosity when the temperature is well below the critical temperature for superconductivity or superfluidity of the nuclear matter.Comment: 15 pages, LaTeX, new appendix and general clarifications in response to referee comment

    Spatially Resolved Stellar Populations of Eight GOODS-South AGN at z~1

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    We present a pilot study of the stellar populations of 8 AGN hosts at z~1 and compare to (1) lower redshift samples and (2) a sample of nonactive galaxies of similar redshift. We utilize K' images in the GOODS South field obtained with the laser guide star adaptive optics (LGSAO) system at Keck Observatory. We combine this K' data with B, V, i, and z imaging from the ACS on HST to give multi-color photometry at a matched spatial resolution better than 100 mas in all bands. The hosts harbor AGN as inferred from their high X-ray luminosities (L_X > 10^42 ergs/s) or mid-IR colors. We find a correlation between the presence of younger stellar populations and the strength of the AGN, as measured with [OIII] line luminosity or X-ray (2-10 keV) luminosity. This finding is consistent with similar studies at lower redshift. Of the three Type II galaxies, two are disk galaxies and one is of irregular type, while in the Type I sample there only one disk-like source and four sources with smooth, elliptical/spheroidal morphologies. In addition, the mid-IR SEDs of the strong Type II AGN indicate that they are excited to LIRG (Luminous InfraRed Galaxy) status via galactic starbursting, while the strong Type I AGN are excited to LIRG status via hot dust surrounding the central AGN. This supports the notion that the obscured nature of Type II AGN at z~1 is connected with global starbursting and that they may be extincted by kpc-scale dusty features that are byproducts of this starbursting.Comment: 56 pages, 39 figures, accepted to A

    The Phoenix Deep Survey: Extremely Red Galaxies and Cluster Candidates

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    We present the results of a study of a sample of 375 Extremely Red Galaxies (ERGs) in the Phoenix Deep Survey, 273 of which constitute a subsample which is 80% complete to K_s = 18.5 over an area of 1160 arcmin^2. The angular correlation function for ERGs is estimated, and the association of ERGs with faint radio sources explored. We find tentative evidence that ERGs and faint radio sources are associated at z > 0.5. A new overdensity-mapping algorithm has been used to characterize the ERG distribution, and identify a number of cluster candidates, including a likely cluster containing ERGs at 0.5 < z < 1. Our algorithm is also used in an attempt to probe the environments in which faint radio sources and ERGs are associated. We find limited evidence that the I - K_s > 4 criterion is more efficient than R - K_s > 5 at selecting dusty star-forming galaxies, rather than passively evolving ERGs.Comment: 14 emulateapj pages, 15 figures, 1 table, accepted for publication in Astronomical Journal. A version with full resolution figures is available at http://www.physics.usyd.edu.au/~asmith/research/ERGpaper.pd
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