510 research outputs found
Best Management Practices for Nitrogen on Coarse Textured Soils
This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu
Best management practices for Nitrogen use in South-Central Minnesota
This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu
Justice Stevens: The First Three Terms
This Special Project undertakes an examination of Justice Stevens\u27 Supreme Court opinions in an effort to identify his philosophical orientations, to evaluate the consistency of his views, and to determine the extent to which he has developed workable analytical methods. To achieve these goals, Justice Stevens\u27 opinions are examined in three contexts: first, the area of federal-state relations,including commerce clause and supremacy clause questions; second, the individual rights area, emphasizing criminal constitutional and first amendment issues, and problems of fifth and fourteenth amendment analysis; and third, questions concerning the proper role of the Supreme Court in the constitutional scheme. Even though any vote cast by a Supreme Court Justice may illustrate a significant aspect of his ideology, this Special Project limits attention to opinions authored by Justice Stevens on the assumption that they most accurately represent his views.\u2
The X-ray Afterglows of GRB 020813 and GRB 021004 with Chandra HETGS: Possible Evidence for a Supernova Prior to GRB 020813
We report on the detection of an emission line near 1.3 keV, which we
associate with blue-shifted hydrogen-like sulfur (S XVI), in a 76.8 ksec
Chandra HETGS spectrum of the afterglow of GRB 020813. The line is detected at
3.3 sigma significance. We also find marginal evidence for a line possibly due
to hydrogen-like silicon (Si XIV) with the same blue-shift. A line from Fe is
not detected, though a very low significance Ni feature may be present. A
thermal model fits the data adequately, but a reflection model may provide a
better fit. There is marginal evidence that the equivalent width of the S XVI
line decrease as the burst fades. We infer from these results that a supernova
likely occurred >~ 2 months prior to the GRB. We find no discrete or variable
spectral features in the Chandra HETGS spectrum of the GRB 021004 afterglow.Comment: 26 pages, 11 figures, submitted to Ap
Associations between frailty, physical performance, and renal biomarkers in older people with advanced chronic kidney disease
Acknowledgments With thanks to the recruiting teams and participants who took part in the BiCARB trial. GS and MDW acknowledge support from the NIHR Newcastle Biomedical Research CentrePeer reviewedPublisher PD
Notch ligation by Delta1 inhibits peripheral immune responses to transplantation antigens by a CD8âș cellâdependent mechanism
Notch signaling plays a fundamental role in determining the outcome of differentiation processes in many tissues. Notch signaling has been implicated in T versus B cell lineage commitment, thymic differentiation, and bone marrow hematopoietic precursor renewal and differentiation. Notch receptors and their ligands are also expressed on the surface of mature lymphocytes and APCs, but the effects of Notch signaling in the peripheral immune system remain poorly defined. The aim of the studies reported here was to investigate the effects of signaling through the Notch receptor using a ligand of the Delta-like family. We show that Notch ligation in the mature immune system markedly decreases responses to transplantation antigens. Constitutive expression of Delta-like 1 on alloantigen-bearing cells renders them nonimmunogenic and able to induce specific unresponsiveness to a challenge with the same alloantigen, even in the form of a cardiac allograft. These effects could be reversed by depletion of CD8âș cells at the time of transplantation. Ligation of Notch on splenic CD8âș cells results in a dramatic decrease in IFN-Îł with a concomitant enhancement of IL-10 production, suggesting that Notch signaling can alter the differentiation potential of CD8âș cells. These data implicate Notch signaling in regulation of peripheral immunity and suggest a novel approach for manipulating deleterious immune responses
Symbiotic starburst-black hole AGN -- I. Isothermal hydrodynamics of the mass-loaded ISM
Compelling evidence associates the nuclei of active galaxies and massive
starbursts. The symbiosis between a compact nuclear starburst stellar cluster
and a massive black hole can self-consistently explain the properties of active
nuclei. The young stellar cluster has a profound effect on the most important
observable properties of active galaxies through its gravity, and by mass
injection through stellar winds, supernovae and stellar collisions. Mass
injection generates a nuclear ISM which flows under gravitational and radiative
forces until it leaves the nucleus or is accreted onto the black hole or
accretion disc.
The radiative force exerted by the black hole--accretion disc radiation field
is not spherically symmetric. This results in complex flows in which regions of
inflow can coexist with high Mach number outflowing winds and hydrodynamic
jets. We present two-dimensional hydrodynamic models of such nISM flows, which
are highly complex and time variable. Shocked shells, jets and explosive
bubbles are produced, with bipolar winds driving out from the nucleus. Our
results graphically illustrate why broad emission line studies have
consistently failed to identify any simple, global flow geometry. The real
structure of the flows is _inevitably_ yet more complex.Comment: 51 pages, 85 postscript figures, Latex, using MNRAS macros, to be
published in MNRAS. Postscript will full resolution pictures and mpeg
simulations available via http://ast.leeds.ac.uk/~rjrw/agn.htm
An Optically Dark GRB Observed by HETE-2: GRB 051022
GRB 051022 was detected at 13:07:58 on 22 October 2005 by HETE-2. The
location of GRB 051022 was determined immediately by the flight localization
system. This burst contains multiple pulses and has a rather long duration of
about 190 seconds. The detections of candidate X-ray and radio afterglows were
reported, whereas no optical afterglow was found. The optical spectroscopic
observations of the host galaxy revealed the redshift z = 0.8. Using the data
derived by HETE-2 observation of the prompt emission, we found the absorption
N_H = 8.8 -2.9/+3.1 x 10^22 cm^-2 and the visual extinction A_V = 49 -16/+17
mag in the host galaxy. If this is the case, no detection of any optical
transient would be quite reasonable. The absorption derived by the Swift XRT
observations of the afterglow is fully consistent with those obtained from the
early HETE-2 observation of the prompt emission. Our analysis implies an
interpretation that the absorbing medium could be outside external shock at R ~
10^16 cm, which may be a dusty molecular cloud.Comment: 6 pages, 2 figures, accepted for publication in PASJ lette
High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data II: The Spring Equatorial Stripe
This is the second paper in a series aimed at finding high-redshift quasars
from five-color (u'g'r'i'z') imaging data taken along the Celestial Equator by
the Sloan Digital Sky Survey (SDSS) during its commissioning phase. In this
paper, we present 22 high-redshift quasars (z>3.6) discovered from ~250 deg^2
of data in the spring Equatorial Stripe, plus photometry for two previously
known high-redshift quasars in the same region of sky. Our success rate of
identifying high-redshift quasars is 68%. Five of the newly discovered quasars
have redshifts higher than 4.6 (z=4.62, 4.69, 4.70, 4.92 and 5.03). All the
quasars have i* < 20.2 with absolute magnitude -28.8 < M_B < -26.1 (h=0.5,
q_0=0.5). Several of the quasars show unusual emission and absorption features
in their spectra, including an object at z=4.62 without detectable emission
lines, and a Broad Absorption Line (BAL) quasar at z=4.92.Comment: 28 pages, AJ in press (Jan 2000), final version with minor changes;
high resolution finding charts available at
http://www.astro.princeton.edu/~fan/paper/qso2.htm
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