4,984 research outputs found
1998 Kansas Performance Tests with Sunflower Hybrids
Sunflower performance tests were conducted by the Kansas Agricultural Experiment Station to provide farmers, extension workers, and private industry with
unbiased agronomic information on many of the
sunflower hybrids marketed in the state. Environmental factors affecting test results and cultural
practices are presented for each individual test site
2004 Kansas Performance Tests with Sunflower Hybrids
Sunflower performance tests were conducted by the Kansas Agricultural Experiment Station to provide farmers, extension workers, and private industry with
unbiased agronomic information on many of the
sunflower hybrids marketed in the state. Environmental factors affecting test results and cultural
practices are presented for each individual test site
2007 Kansas Performance Tests with Sunflower Hybrids
Sunflower performance tests were conducted by the Kansas Agricultural Experiment Station to provide farmers, extension workers, and private industry with
unbiased agronomic information on many of the
sunflower hybrids marketed in the state. Environmental factors affecting test results and cultural
practices are presented for each individual test site
Jet-ISM Interaction in the Radio Galaxy 3C293: Jet-driven Shocks Heat ISM to Power X-ray and Molecular H2 emission
We present a 70ks Chandra observation of the radio galaxy 3C293. This galaxy
belongs to the class of molecular hydrogen emission galaxies (MOHEGs) that have
very luminous emission from warm molecular hydrogen. In radio galaxies, the
molecular gas appears to be heated by jet-driven shocks, but exactly how this
mechanism works is still poorly understood. With Chandra, we observe X-ray
emission from the jets within the host galaxy and along the 100 kpc radio jets.
We model the X-ray spectra of the nucleus, the inner jets, and the X-ray
features along the extended radio jets. Both the nucleus and the inner jets
show evidence of 10^7 K shock-heated gas. The kinetic power of the jets is more
than sufficient to heat the X-ray emitting gas within the host galaxy. The
thermal X-ray and warm H2 luminosities of 3C293 are similar, indicating similar
masses of X-ray hot gas and warm molecular gas. This is consistent with a
picture where both derive from a multiphase, shocked interstellar medium (ISM).
We find that radio-loud MOHEGs that are not brightest cluster galaxies (BCGs),
like 3C293, typically have LH2/LX~1 and MH2/MX~1, whereas MOHEGs that are BCGs
have LH2/LX~0.01 and MH2/MX~0.01. The more massive, virialized, hot atmosphere
in BCGs overwhelms any direct X-ray emission from current jet-ISM interaction.
On the other hand, LH2/LX~1 in the Spiderweb BCG at z=2, which resides in an
unvirialized protocluster and hosts a powerful radio source. Over time, jet-ISM
interaction may contribute to the establishment of a hot atmosphere in BCGs and
other massive elliptical galaxies.Comment: Accepted by ApJ 21 pages in ApJ format, 9 figures, 8 table
The Arches cluster revisited: II. A massive eclipsing spectroscopic binary in the Arches cluster
We have carried out a spectroscopic variability survey of some of the most massive stars in the Arches cluster, using K-band observations obtained with SINFONI on the VLT. One target, F2, exhibits substantial changes in radial velocity; in combination with new KMOS and archival SINFONI spectra, its primary component is found to undergo radial velocity variation with a period of 10.483+/-0.002 d and an amplitude of ~350 km/s-1. A secondary radial velocity curve is also marginally detectable. We reanalyse archival NAOS-CONICA photometric survey data in combination with our radial velocity results to confirm this object as an eclipsing SB2 system, and the first binary identified in the Arches. We model it as consisting of an 82+/-12 M⊙ WN8-9h primary and a 60+/-8 M⊙ O5-6 Ia+ secondary, and as having a slightly eccentric orbit, implying an evolutionary stage prior to strong binary interaction. As one of four X-ray bright Arches sources previously proposed as colliding-wind massive binaries, it may be only the first of several binaries to be discovered in this cluster, presenting potential challenges to recent models for the Arches' age and composition. It also appears to be one of the most massive binaries detected to date; the primary's calculated initial mass of >~120 M⊙ would arguably make this the most massive binary known in the Galaxy
Economic evaluation of short treatment for multidrugresistant tuberculosis, Ethiopia and South Africa : the STREAM trial
OBJECTIVE
STREAM was a phase-III non-inferiority randomised controlled trial (RCT) to evaluate a shortened regimen for multi-drug resistant tuberculosis (MDR-TB), and included the first-ever within-trial economic evaluation of such regimens, reported here.
METHODS
We compared the costs of ‘Long’ (20-22 months) and ‘Short’ (9-11 months) regimens in Ethiopia and South Africa. Cost data were collected from trial participants, and health system costs estimated using ‘bottom-up’ and ‘top-down’ costing approaches. A cost-effectiveness analysis was conducted with the trial primary outcome as the measure of effectiveness, including a probabilistic sensitivity analysis (PSA) to illustrate decision uncertainty.
FINDINGS
The Short-regimen reduced healthcare costs per case by 21% in South Africa (US6,619 Short) and 25% in Ethiopia (US4,552 Short). The largest component of this saving was medication in South Africa (67%) and social support in Ethiopia (35%). In Ethiopia, participants on the Short-regimen reported reductions in dietary supplementation expenditure (US13 (95%CI 11-14), South Africa US19,000 (Ethiopia) or <US$14,500 (South Africa).
CONCLUSION
The Short-regimen provided substantial health system cost savings and reduced financial burden on participants. Shorter regimens are likely to be cost-effective in most settings, and an effective strategy to support the WHO goal of eliminating catastrophic costs in T
Very Red and Extremely Red Galaxies in the Fields of z ~ 1.5 Radio-Loud Quasars
We previously identified an excess of mostly red galaxies around 31 RLQs at
z=1-2. These fields have an ERO (extremely red object, R-K>6) density 2.7 times
higher than the field. Assuming the EROs are passively evolved galaxies at the
quasar redshifts, they have characteristic luminosities of only ~L^*. We also
present new observations of four z~1.54 RLQ fields: (1) Wide-field J & Ks data
confirm an Abell richness ~2 excess within 140" of Q0835+580 but an excess only
within 50" of Q1126+101. (2) In 3 fields we present deep narrow-band redshifted
H-alpha observations. We detect five candidate galaxies at the quasar
redshifts, a surface density 2.5x higher than the field. (3) SCUBA sub-mm
observations of 3 fields detect 2 quasars and 2 galaxies with SEDs best fit as
highly reddened galaxies at the quasar z. (4) H-band adaptive optics (AO)
imaging is used to estimate redshifts for 2 red, bulge-dominated galaxies using
the Kormendy relation. Both have structural redshifts foreground to the quasar,
but these are not confirmed by photometric redshifts, possibly because their
optical photometry is corrupted by scattered light from the AO guidestar. (5)
We use quantitative SED fits to constrain the photometric redshifts z_ph for
some galaxies. Most galaxies near Q0835+580 are consistent with being at its
redshift, including a candidate very old passively evolving galaxy. Many very &
extremely red objects have z_ph z_q, and dust reddening is required to fit most
of them, including many objects whose fits also require relatively old stellar
populations. Large reddenings of E(B-V)~0.6 are required to fit four J-K
selected EROs, though all but one of them have best-fit z_ph>z_q. These objects
may represent a population of dusty high-z galaxies underrepresented in
optically selected samples. (Abridged)Comment: Missing object 1126.424 added to Table 4; title changed to save
people the apparent trouble of reading the abstract. 38 pages, 16 figures, 2
in color; all-PostScript figure version available from
http://astro.princeton.edu/~pathall/tp3.ps.g
Iris: an Extensible Application for Building and Analyzing Spectral Energy Distributions
Iris is an extensible application that provides astronomers with a
user-friendly interface capable of ingesting broad-band data from many
different sources in order to build, explore, and model spectral energy
distributions (SEDs). Iris takes advantage of the standards defined by the
International Virtual Observatory Alliance, but hides the technicalities of
such standards by implementing different layers of abstraction on top of them.
Such intermediate layers provide hooks that users and developers can exploit in
order to extend the capabilities provided by Iris. For instance, custom Python
models can be combined in arbitrary ways with the Iris built-in models or with
other custom functions. As such, Iris offers a platform for the development and
integration of SED data, services, and applications, either from the user's
system or from the web. In this paper we describe the built-in features
provided by Iris for building and analyzing SEDs. We also explore in some
detail the Iris framework and software development kit, showing how astronomers
and software developers can plug their code into an integrated SED analysis
environment.Comment: 18 pages, 8 figures, accepted for publication in Astronomy &
Computin
Spatially Resolved Chandra HETG Spectroscopy of the NLR Ionization Cone in NGC 1068
We present initial results from a new 440-ks Chandra HETG GTO observation of
the canonical Seyfert 2 galaxy NGC 1068. The proximity of NGC 1068, together
with Chandra's superb spatial and spectral resolution, allow an unprecedented
view of its nucleus and circumnuclear NLR. We perform the first spatially
resolved high-resolution X-ray spectroscopy of the `ionization cone' in any
AGN, and use the sensitive line diagnostics offered by the HETG to measure the
ionization state, density, and temperature at discrete points along the ionized
NLR. We argue that the NLR takes the form of outflowing photoionized gas,
rather than gas that has been collisionally ionized by the small-scale radio
jet in NGC 1068. We investigate evidence for any velocity gradients in the
outflow, and describe our next steps in modeling the spatially resolved spectra
as a function of distance from the nucleus.Comment: 5 pages, 2 figures, 1 video. To appear in refereed Proceedings of
"X-ray Astronomy 2009: Present Status, Multi-Wavelength Approach and Future
Perspectives", Bologna, Italy, September 7-11, 2009, AIP, eds. A. Comastri,
M. Cappi, and L. Angelin
Quantum corrections to critical phenomena in gravitational collapse
We investigate conformally coupled quantum matter fields on spherically
symmetric, continuously self-similar backgrounds. By exploiting the symmetry
associated with the self-similarity the general structure of the renormalized
quantum stress-energy tensor can be derived. As an immediate application we
consider a combination of classical, and quantum perturbations about exactly
critical collapse. Generalizing the standard argument which explains the
scaling law for black hole mass, , we
demonstrate the existence of a quantum mass gap when the classical critical
exponent satisfies . When our argument is
inconclusive; the semi-classical approximation breaks down in the spacetime
region of interest.Comment: RevTeX, 6 pages, 3 figures included using psfi
- …