6,768 research outputs found

    Kent M. Terwilliger; graduate school at Berkeley and early years at Michigan, 1949–1959

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    Kent Terwilliger’s years as a graduate student and a junior faculty member at Michigan are recalled. The early research activities at Michigan with the synchrotron and the cyclotron, the beginnings of MURA, and the Michigan Model FFAG accelerator are described. (AIP)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87537/2/1_1.pd

    Particle accelerators and discoveries in elementary particle physics

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    Some discoveries in elementary particle physics are recounted from personal and historical perspective with particular reference to their interaction with particle accelerators. The particle examples chosen include the ψ/J, the Υ, and the study of nucleon constituents with inelastic electron scattering. Precursors experiments are cited together with the better known discoveries.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87362/2/2280_1.pd

    Possible experiments with polarized neutrons at the ZGS and at FNAL

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87413/2/158_1.pd

    THE FIRST CENTURY OF COSMIC RAYS, AN HISTORICAL OVERVIEW

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    The 1912 balloon flights of Victor Hess and related activities in those years are reviewed. Subsequent research during the early 20th Century is noted, including the discovery of the positron, mesons, and air showers. The cosmic ray–accelerator interrelations are noted, including cosmic ray studies at Echo Lake and Mt. Evans, Colorado (USA). The more recent evolution of cosmic ray research programs to astrophysical and cosmological studies, and the major programs such as Auger and AMS conclude this discussion of the century of cosmic ray research

    Kinematics of X‐Ray–Emitting Components in Cassiopeia A

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    We present high-resolution X-ray proper-motion measurements of Cassiopeia A using Chandra X-Ray Observatory observations from 2000 and 2002. We separate the emission into four spectrally distinct classes: Si-dominated, Fe-dominated, low-energy-enhanced, and continuum-dominated. These classes also represent distinct spatial and kinematic components. The Si- and Fe-dominated classes are ejecta and have a mean expansion rate of 0.2% yr-1. This is the same as for the forward shock filaments but less than the 0.3% yr-1 characteristic of optical ejecta. The low-energy-enhanced spectral class possibly illuminates a clumpy circumstellar component and has a mean expansion rate of 0.05% yr-1. The continuum-dominated emission likely represents the forward shock and consists of diffuse circumstellar material, which is seen as a circular ring around the periphery of the remnant as well as projected across the center

    The separations between hadrons and electromagnetic particles using an ionization calorimeter

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    The separation of hadrons from photons or electrons using an ionization spectrometer or calorimeter is studied. The seperate recording of ionization and Cherenkov signals from the same sampling layer is suggested as a means of achieving a separation down to 0.1%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22871/1/0000434.pd

    Radio Galaxy Zoo: The Distortion of Radio Galaxies by Galaxy Clusters

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    We study the impact of cluster environment on the morphology of a sample of 4304 extended radio galaxies from Radio Galaxy Zoo. A total of 87% of the sample lies within a projected 15 Mpc of an optically identified cluster. Brightest cluster galaxies (BCGs) are more likely than other cluster members to be radio sources, and are also moderately bent. The surface density as a function of separation from cluster center of non-BCG radio galaxies follows a power law with index 1.10±0.03-1.10\pm 0.03 out to 10 r50010~r_{500} (7 \sim 7~Mpc), which is steeper than the corresponding distribution for optically selected galaxies. Non-BCG radio galaxies are statistically more bent the closer they are to the cluster center. Within the inner 1.5 r5001.5~r_{500} (1 \sim 1~Mpc) of a cluster, non-BCG radio galaxies are statistically more bent in high-mass clusters than in low-mass clusters. Together, we find that non-BCG sources are statistically more bent in environments that exert greater ram pressure. We use the orientation of bent radio galaxies as an indicator of galaxy orbits and find that they are preferentially in radial orbits. Away from clusters, there is a large population of bent radio galaxies, limiting their use as cluster locators; however, they are still located within statistically overdense regions. We investigate the asymmetry in the tail length of sources that have their tails aligned along the radius vector from the cluster center, and find that the length of the inward-pointing tail is weakly suppressed for sources close to the center of the cluster.Comment: 23 pages, 17 figures, 2 tables. Supplemental data files available in The Astronomical Journal or contact autho

    A prompt neutrino measurement

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    A test has been made to explore the possibility of beam dump neutrino experiments with short target‐detector separations and modest detectors. Results have given a positive neutrino signal which is interpreted in the context of various charmed‐meson production models. A limit to the lifetime and mass of the axion is also a byproduct of this test.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87326/2/246_1.pd

    Drip Paintings and Fractal Analysis

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    It has been claimed [1-6] that fractal analysis can be applied to unambiguously characterize works of art such as the drip paintings of Jackson Pollock. This academic issue has become of more general interest following the recent discovery of a cache of disputed Pollock paintings. We definitively demonstrate here, by analyzing paintings by Pollock and others, that fractal criteria provide no information about artistic authenticity. This work has also led to two new results in fractal analysis of more general scientific significance. First, the composite of two fractals is not generally scale invariant and exhibits complex multifractal scaling in the small distance asymptotic limit. Second the statistics of box-counting and related staircases provide a new way to characterize geometry and distinguish fractals from Euclidean objects

    Characterization of a panel of six β2-adrenergic receptor antibodies by indirect immunofluorescence microscopy

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    <p>Abstract</p> <p>Background</p> <p>The β<sub>2</sub>-adrenergic receptor (β<sub>2</sub>AR) is a primary target for medications used to treat asthma. Due to the low abundance of β<sub>2</sub>AR, very few studies have reported its localization in tissues. However, the intracellular location of β<sub>2</sub>AR in lung tissue, especially in airway smooth muscle cells, is very likely to have a significant impact on how the airways respond to β-agonist medications. Thus, a method for visualizing β<sub>2</sub>AR in tissues would be of utility. The purpose of this study was to develop an immunofluorescent labeling technique for localizing native and recombinant β<sub>2</sub>AR in primary cell cultures.</p> <p>Methods</p> <p>A panel of six different antibodies were evaluated in indirect immunofluorescence assays for their ability to recognize human and rat β<sub>2</sub>AR expressed in HEK 293 cells. Antibodies capable of recognizing rat β<sub>2</sub>AR were identified and used to localize native β<sub>2</sub>AR in primary cultures of rat airway smooth muscle and epithelial cells. β<sub>2</sub>AR expression was confirmed by performing ligand binding assays using the β-adrenergic antagonist [3H] dihydroalprenolol <sup>([3H]DHA)</sup>.</p> <p>Results</p> <p>Among the six antibodies tested, we identified three of interest. An antibody developed against the C-terminal 15 amino acids of the human β<sub>2</sub>AR (Ab-Bethyl) specifically recognized human but not rat β<sub>2</sub>AR. An antibody developed against the C-terminal domain of the mouse β<sub>2</sub>AR (Ab-sc570) specifically recognized rat but not human β<sub>2</sub>AR. An antibody developed against 78 amino acids of the C-terminus of the human β<sub>2</sub>AR (Ab-13989) was capable of recognizing both rat and human β<sub>2</sub>ARs. In HEK 293 cells, the receptors were predominantly localized to the cell surface. By contrast, about half of the native rat β<sub>2</sub>AR that we visualized in primary cultures of rat airway epithelial and smooth muscle cells using Ab-sc570 and Ab-13989 was found inside cells rather than on their surface.</p> <p>Conclusion</p> <p>Antibodies have been identified that recognize human β<sub>2</sub>AR, rat β<sub>2</sub>AR or both rat and human β<sub>2</sub>AR. Interestingly, the pattern of expression in transfected cells expressing millions of receptors was dramatically different from that in primary cell cultures expressing only a few thousand native receptors. We anticipate that these antibodies will provide a valuable tool for evaluating the expression and trafficking of β<sub>2</sub>AR in tissues.</p
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