1,581 research outputs found
OPTIMAL IRRIGATION PIVOT LOCATION ON IRREGULARLY SHAPED FIELDS
Although annual rainfall in the Southeast is adequate, its distribution is a potential constraint to agricultural production. Farmers require production information concerning efficient use of irrigation technology adapted to regional growing conditions. Selection of optimal position, size, and number of pivots in center pivot irrigation systems poses special problems on small, irregularly shaped fields. In the southeastern United States, field size and shape are often varied and irregular. A mixed integer programming model was constructed to assist in irrigation investment decisions. The model is illustrated using irrigated peanut production in southeast Alabama. Results indicate the importance of economic engineering considerations.Farm Management,
Nonlinear magneto-optical rotation in optically thick media
Nonlinear magneto-optical rotation is a sensitive technique for measuring
magnetic fields. Here, the shot-noise-limited magnetometric sensitivity is
analyzed for the case of optically-thick media and high light power, which has
been the subject of recent experimental and theoretical investigations.Comment: 7 pages, 4 figure
What are the important thresholds and relationships to inform the management of COTS? Draft report, 30 June 2014
[Extract] The crown-of-thorns seastar (COTS), Acanthaster planci, is one of the main contributors to declines in coral cover on the Great Barrier Reef (GBR), and remains one of the major acute disturbances on coral reefs throughout much of the Indo-Pacific. The aim of this project is to investigate important ecological thresholds and relationships to inform the management of COTS. To do this we use a range of modelling methods as well as analyses of all available empirical data. Data from the management program removals of COTS provide near-real-time CPUE (Catch-Per-Unit-Effort) data that can be used to inform management
Production and detection of atomic hexadecapole at Earth's magnetic field
Anisotropy of atomic states is characterized by population differences and
coherences between Zeeman sublevels. It can be efficiently created and probed
via resonant interactions with light, the technique which is at the heart of
modern atomic clocks and magnetometers. Recently, nonlinear magneto-optical
techniques have been developed for selective production and detection of higher
polarization moments, hexadecapole and hexacontatetrapole, in the ground states
of the alkali atoms. Extension of these techniques into the range of
geomagnetic fields is important for practical applications. This is because
hexadecapole polarization corresponding to the Zeeman coherence,
with maximum possible for electronic angular momentum and
nuclear spin , is insensitive to the nonlinear Zeeman effect (NLZ). This
is of particular interest because NLZ normally leads to resonance splitting and
systematic errors in atomic magnetometers. However, optical signals due to the
hexadecapole moment decline sharply as a function of magnetic field. We report
a novel method that allows selective creation of a macroscopic long-lived
ground-state hexadecapole polarization. The immunity of the hexadecapole signal
to NLZ is demonstrated with F=2 Rb atoms at Earth's field.Comment: 4 pages, 5 figure
Toward a regulatory qualification of real-world mobility performance biomarkers in Parkinson’s patients using Digital Mobility Outcomes
Wearable inertial sensors can be used to monitor mobility in real-world settings over extended periods. Although these technologies are widely used in human movement research, they have not yet been qualified by drug regulatory agencies for their use in regulatory drug trials. This is because the first generation of these sensors was unreliable when used on slow-walking subjects. However, intense research in this area is now offering a new generation of algorithms to quantify Digital Mobility Outcomes so accurate they may be considered as biomarkers in regulatory drug trials. This perspective paper summarises the work in the Mobilise-D consortium around the regulatory qualification of the use of wearable sensors to quantify real-world mobility performance in patients affected by Parkinson’s Disease. The paper describes the qualification strategy and both the technical and clinical validation plans, which have recently received highly supportive qualification advice from the European Medicines Agency. The scope is to provide detailed guidance for the preparation of similar qualification submissions to broaden the use of real-world mobility assessment in regulatory drug trials
Microarray Analyses of Gene Expression during the Tetrahymena thermophila Life Cycle
The model eukaryote, Tetrahymena thermophila, is the first ciliated protozoan whose genome has been sequenced, enabling genome-wide analysis of gene expression.A genome-wide microarray platform containing the predicted coding sequences (putative genes) for T. thermophila is described, validated and used to study gene expression during the three major stages of the organism's life cycle: growth, starvation and conjugation.Of the approximately 27,000 predicted open reading frames, transcripts homologous to only approximately 5900 are not detectable in any of these life cycle stages, indicating that this single-celled organism does indeed contain a large number of functional genes. Transcripts from over 5000 predicted genes are expressed at levels >5x corrected background and 95 genes are expressed at >250x corrected background in all stages. Transcripts homologous to 91 predicted genes are specifically expressed and 155 more are highly up-regulated in growing cells, while 90 are specifically expressed and 616 are up-regulated during starvation. Strikingly, transcripts homologous to 1068 predicted genes are specifically expressed and 1753 are significantly up-regulated during conjugation. The patterns of gene expression during conjugation correlate well with the developmental stages of meiosis, nuclear differentiation and DNA elimination. The relationship between gene expression and chromosome fragmentation is analyzed. Genes encoding proteins known to interact or to function in complexes show similar expression patterns, indicating that co-ordinate expression with putative genes of known function can identify genes with related functions. New candidate genes associated with the RNAi-like process of DNA elimination and with meiosis are identified and the late stages of conjugation are shown to be characterized by specific expression of an unexpectedly large and diverse number of genes not involved in nuclear functions
Nonlinear magneto-optical rotation with frequency-modulated light in the geophysical field range
Recent work investigating resonant nonlinear magneto-optical rotation (NMOR)
related to long-lived (\tau\ts{rel} \sim 1 {\rm s}) ground-state atomic
coherences has demonstrated potential magnetometric sensitivities exceeding
for small () magnetic
fields. In the present work, NMOR using frequency-modulated light (FM NMOR) is
studied in the regime where the longitudinal magnetic field is in the
geophysical range (), of particular interest for many
applications. In this regime a splitting of the FM NMOR resonance due to the
nonlinear Zeeman effect is observed. At sufficiently high light intensities,
there is also a splitting of the FM NMOR resonances due to ac Stark shifts
induced by the optical field, as well as evidence of alignment-to-orientation
conversion type processes. The consequences of these effects for FM-NMOR-based
atomic magnetometry in the geophysical field range are considered.Comment: 8 pages, 8 figure
Selective addressing of high-rank atomic polarization moments
We describe a method of selective generation and study of polarization
moments of up to the highest rank possible for a quantum state with
total angular momentum . The technique is based on nonlinear magneto-optical
rotation with frequency-modulated light. Various polarization moments are
distinguished by the periodicity of light-polarization rotation induced by the
atoms during Larmor precession and exhibit distinct light-intensity and
frequency dependences. We apply the method to study polarization moments of
Rb atoms contained in a vapor cell with antirelaxation coating. Distinct
ultra-narrow (1-Hz wide) resonances, corresponding to different multipoles,
appear in the magnetic-field dependence of the optical rotation. The use of the
highest-multipole resonances has important applications in quantum and
nonlinear optics and in magnetometry.Comment: 5 pages, 6 figure
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