5,044 research outputs found
Adaptive data acquisition multiplexing system and method
A reconfigurable telemetry multiplexer is described which includes a monitor-terminal and a plurality of remote terminals. The remote terminals each include signal conditioning for a plurality of sensors for measuring parameters which are converted by an analog to digital converter. CPU's in the remote terminals store instructions for prompting system configuration and reconfiguration commands. The measurements, instructions, and the terminal's present configuration and status data are transmitted to the monitor-terminal and displayed. In response to menu-driven prompts generated and displayed at the monitor-terminal, data generation request commands, status and health commands, and the like are input at the monitor-terminal and transmitted to the remote terminals. The CPU in each remote terminal receives the various commands, stores them in electrically alterable memory, and reacts in accordance with the commands to reconfigure a plurality of aspects of the system. The CPU in each terminal also generates parameter measurements, status and health signals, and transmits these signals of the respective terminals to the monitor-terminal for low data rate operator viewing and to higher rate external transmission/monitor equipment. Reconfiguration may be in real time during the general period of parameter measurement acquisition, and may include alteration of the gain, automatic gain rescaling, bias, and or sampling rates associated with one or more of the parameter measurements made by the remote terminals
An assessment of the efficacy of deep drains constructed in the wheatbelt of Western Australia Part 1 A discussion on drainage implmentation in the wheatbelt : a case study review, summary, conclusions and recommendations
Australia has undertaken a strategic review of current and historical deep drainage projects. A \u27rapid appraisal\u27 methodology was utilised, based principally on existing hydrological investigations and interpretation and anecdotal evidence provided by landholders to clarify the role of drainage in managing water in dry land rural landscapes.
The objectives of this discussion paper are to:
1. Review the current status of groundwater drainage practice
2. Provide an assessment of deep drains in the landscape and
3. Propose recommendations on the development of drainage policy to enable the application of best management practice in groundwater drainage.https://researchlibrary.agric.wa.gov.au/bulletins/1012/thumbnail.jp
CHANG-ES V: Nuclear Radio Outflow in a Virgo Cluster Spiral after a Tidal Disruption Event
We have observed the Virgo Cluster spiral galaxy, NGC~4845, at 1.6 and 6 GHz
using the Karl G. Jansky Very Large Array, as part of the `Continuum Halos in
Nearby Galaxies -- an EVLA Survey' (CHANG-ES). The source consists of a bright
unresolved core with a surrounding weak central disk (1.8 kpc diameter). The
core is variable over the 6 month time scale of the CHANG-ES data and has
increased by a factor of 6 since 1995. The wide bandwidths of
CHANG-ES have allowed us to determine the spectral evolution of this core which
peaks {\it between} 1.6 and 6 GHz (it is a GigaHertz-peaked spectrum source).We
show that the spectral turnover is dominated by synchrotron self-absorption and
that the spectral evolution can be explained by adiabatic expansion (outflow),
likely in the form of a jet or cone. The CHANG-ES observations serendipitously
overlap in time with the hard X-ray light curve obtained by Nikolajuk \& Walter
(2013) which they interpret as due to a tidal disruption event (TDE) of a
super-Jupiter mass object around a black hole. We outline a
standard jet model, provide an explanation for the observed circular
polarization, and quantitatively suggest a link between the peak radio and peak
X-ray emission via inverse Compton upscattering of the photons emitted by the
relativistic electrons. We predict that it should be possible to resolve a
young radio jet via VLBI as a result of this nearby TDE.Comment: 45 pages, 10 figures, accepted July 2, 2015 to the Astrophysical
Journa
Corn cutworm control for 1983
"This guide recommends management practices and insecticides for reduction of injury caused by the various cutworms attacking com in Missouri. It also discusses the life cycles of the more common species which feed at and below ground and those species which are primarily above ground foliage feeders."--First page.George W. Thomas, Armon J. Keasler, Richard N. Story and Judy A. Grundler (Department of Entomology, College of Agriculture)Revised 2/83/8
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Identification of candidate genes affecting Delta9-tetrahydrocannabinol biosynthesis in Cannabis sativa.
RNA isolated from the glands of a Delta(9)-tetrahydrocannabinolic acid (THCA)-producing strain of Cannabis sativa was used to generate a cDNA library containing over 100 000 expressed sequence tags (ESTs). Sequencing of over 2000 clones from the library resulted in the identification of over 1000 unigenes. Candidate genes for almost every step in the biochemical pathways leading from primary metabolites to THCA were identified. Quantitative PCR analysis suggested that many of the pathway genes are preferentially expressed in the glands. Hexanoyl-CoA, one of the metabolites required for THCA synthesis, could be made via either de novo fatty acids synthesis or via the breakdown of existing lipids. qPCR analysis supported the de novo pathway. Many of the ESTs encode transcription factors and two putative MYB genes were identified that were preferentially expressed in glands. Given the similarity of the Cannabis MYB genes to those in other species with known functions, these Cannabis MYBs may play roles in regulating gland development and THCA synthesis. Three candidates for the polyketide synthase (PKS) gene responsible for the first committed step in the pathway to THCA were characterized in more detail. One of these was identical to a previously reported chalcone synthase (CHS) and was found to have CHS activity. All three could use malonyl-CoA and hexanoyl-CoA as substrates, including the CHS, but reaction conditions were not identified that allowed for the production of olivetolic acid (the proposed product of the PKS activity needed for THCA synthesis). One of the PKS candidates was highly and specifically expressed in glands (relative to whole leaves) and, on the basis of these expression data, it is proposed to be the most likely PKS responsible for olivetolic acid synthesis in Cannabis glands
Detecting the stochastic gravitational wave background using pulsar timing
The direct detection of gravitational waves is a major goal of current
astrophysics. We provide details of a new method for detecting a stochastic
background of gravitational waves using pulsar timing data. Our results show
that regular timing observations of 40 pulsars each with a timing accuracy of
100 nano-seconds will be able to make a direct detection of the predicted
stochastic background from coalescing black holes within five years. With an
improved pre-whitening algorithm, or if the background is at the upper end of
the predicted range, a significant detection should be possible with only 20
pulsars.Comment: Accepted by ApJ Letter
Mapping High-velocity H-alpha and Lyman-alpha Emission from Supernova 1987A
We present new {\it Hubble Space Telescope} images of high-velocity
H- and Lyman- emission in the outer debris of SN~1987A. The
H- images are dominated by emission from hydrogen atoms crossing the
reverse shock. For the first time we observe emission from the reverse shock
surface well above and below the equatorial ring, suggesting a bipolar or
conical structure perpendicular to the ring plane. Using the H imaging,
we measure the mass flux of hydrogen atoms crossing the reverse shock front, in
the velocity intervals (7,500~~~~2,800 km s) and
(1,000~~~~7,500 km s), =
1.2~~10 M yr. We also present the first
Lyman- imaging of the whole remnant and new X-ray
observations. Comparing the spatial distribution of the Lyman- and
X-ray emission, we observe that the majority of the high-velocity
Lyman- emission originates interior to the equatorial ring. The
observed Lyman-/H- photon ratio, ~17, is significantly higher than the theoretically
predicted ratio of 5 for neutral atoms crossing the reverse shock
front. We attribute this excess to Lyman- emission produced by X-ray
heating of the outer debris. The spatial orientation of the Lyman- and
X-ray emission suggests that X-ray heating of the outer debris is the dominant
Lyman- production mechanism in SN 1987A at this phase in its evolution.Comment: 6 pages, 5 figures. ApJL - accepte
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