10,416 research outputs found
Agribusiness and space: No limits to growth
Technological developments responding to world food needs are examined. It is noted that agribusiness technology has become more space-related in recent years. Although crops forecasting and improvements in yield (the green revolution) were developed prior to the space era, it would be unthinkable today to ignore the contributions of operational meteorological and communications satellites and experimental Earth observation satellites in agribusiness. Space-driven communications now permit national agribusiness database management networks, with a significant portion of the data being space-derived. In demonstration experiments, space communications were shown to improve those aspects of the food problem related to education and communications
Turbulence and waves over irregularly sloping topography : cruise report - Oceanus 324
This report documents the work of R/V Oceanus cruise 324, which occurred during May of 1998.
This cruise was the field component of the Turbulence and Waves in Irregularly Sloping
Topography (TWIST) program. TWIST was part of the Littoral Internal Wave Initiative (LIW)
supported by the Office of Naval Research.
The objective of TWIST was to sample the background, internal wave and turbulence properties
on the Continental Slope in the Mid-Atlantic Bight. Previous investigations have revealed
strongly enhanced finescale internal wavefields and much more energetic turbulence due to
internal wave breaking above topographic roughness associated with the Mid-Atlantic Ridge. So,
an area of steeply sloping ridges and troughs running perpendicular to the continental slope near
36Ëš34'N, 74Ëš39'W was chosen as the site of the observational program due to its topographic
similarity to the Mid-Atlantic Ridge.
FĂve instrument systems were employed to make observations during this cruise: the High
Resolution Profier (HRP), three Moored Profiler (MP) moorings, a Lowered Acoustic Doppler
Current Profiler/Conductivity, Temperature, Depth (LADCP/CTD) rosette, eXpendable Current
Profilers/eXpendable CTD (XCP/XCTD), and finally, the shipboard ADCP. The data from these
instruments (more than 1100 full depth profiles) provide adequate spatial and temporal resolution
to describe the finescale and turbulent processes observed.Funding was provided by the Office of Naval Research under Grant No. N00014-97-1-0087
Influence of PCR reagents on DNA polymerase extension rates measured on real-time PCR instruments
pre-printBACKGROUND: Radioactive DNA polymerase activity methods are cumbersome and do not provide initial extension rates. A simple extension rate assay would enable study of basic assumptions about PCR and define the limits of rapid PCR. METHODS: A continuous assay that monitors DNA polymerase extension using noncovalent DNA dyes on common real-time PCR instruments was developed. Extension rates were measured in nucleotides per second per molecule of polymerase. To initiate the reaction, a nucleotide analog was heat activated at 95 °C for 5 min, the temperature decreased to 75 °C, and fluorescence monitored until substrate exhaustion in 30-90 min. RESULTS: The assay was linear with time for over 40% of the reaction and for polymerase concentrations over a 100-fold range (1-100 pmol/L). Extension rates decreased continuously with increasing monovalent cation concentrations (lithium, sodium, potassium, cesium, and ammonium). Melting-temperature depressors had variable effects. DMSO increased rates up to 33%, whereas glycerol had little effect. Betaine, formamide, and 1,2-propanediol decreased rates with increasing concentrations. Four common noncovalent DNA dyes inhibited polymerase extension. Heat-activated nucleotide analogs were 92% activated after 5 min, and hot start DNA polymerases were 73%-90% activated after 20 min. CONCLUSIONS: Simple DNAextension rate assays can be performed on real-time PCR instruments. Activity is decreased by monovalent cations,DNA dyes, and most melting temperature depressors. Rational inclusion of PCR components on the basis of their effects on polymerase extension is likely to be useful in PCR, particularly rapid-cycle or fast PCR
Kinetic modelling and molecular dynamics simulation of ultracold neutral plasmas including ionic correlations
A kinetic approach for the evolution of ultracold neutral plasmas including
interionic correlations and the treatment of ionization/excitation and
recombination/deexcitation by rate equations is described in detail. To assess
the reliability of the approximations inherent in the kinetic model, we have
developed a hybrid molecular dynamics method. Comparison of the results reveals
that the kinetic model describes the atomic and ionic observables of the
ultracold plasma surprisingly well, confirming our earlier findings concerning
the role of ion-ion correlations [Phys. Rev. A {\bf 68}, 010703]. In addition,
the molecular dynamics approach allows one to study the relaxation of the ionic
plasma component towards thermodynamical equilibrium
A Bayesian approach to the estimation of maps between riemannian manifolds
Let \Theta be a smooth compact oriented manifold without boundary, embedded
in a euclidean space and let \gamma be a smooth map \Theta into a riemannian
manifold \Lambda. An unknown state \theta \in \Theta is observed via
X=\theta+\epsilon \xi where \epsilon>0 is a small parameter and \xi is a white
Gaussian noise. For a given smooth prior on \Theta and smooth estimator g of
the map \gamma we derive a second-order asymptotic expansion for the related
Bayesian risk. The calculation involves the geometry of the underlying spaces
\Theta and \Lambda, in particular, the integration-by-parts formula. Using this
result, a second-order minimax estimator of \gamma is found based on the modern
theory of harmonic maps and hypo-elliptic differential operators.Comment: 20 pages, no figures published version includes correction to eq.s
31, 41, 4
Lipid droplet detection by the cavity perturbation method
There are currently no point-of-care diagnosis strategies available to indicate the presence of neoplasmic growth. This research aims to develop a novel diagnostic strategy based on detecting TAG accumulation in cells. This element of the research is a preliminary experiment to prove the concept of detecting TAG lipid droplets in YEPD media. It was found that a change in mono-unsaturated concentration can be detected by the frequency shift in a resonant cavity. The dielectric constant of TAG vegetable oils was calculated at 2.34-2.39. It was also found that concentrations of lipid droplet can be differentiated up to 5% (v/v)
Components of active music interventions in therapeutic settings: Present and future applications
Musical interventions in therapy have become increasingly relevant for rehabilitation in many clinics. What was long known for physiotherapy training-that the agency of the participant is crucial and moving is much more efficient for rehabilitation success than being moved-has over recent years also been shown to be true for music therapy. Accumulating evidence suggests that active musical interventions are especially efficient at helping rehabilitation success. Here, we review various approaches to active music therapy. Furthermore, we present several components that allow for manipulating musical expressiveness and physical engagement during active musical interventions, applying a technology-based music feedback paradigm. This paper will allow for a transfer of insights to other domains of music-based therapeutic interventions
Optimal rotations of deformable bodies and orbits in magnetic fields
Deformations can induce rotation with zero angular momentum where dissipation
is a natural ``cost function''. This gives rise to an optimization problem of
finding the most effective rotation with zero angular momentum. For certain
plastic and viscous media in two dimensions the optimal path is the orbit of a
charged particle on a surface of constant negative curvature with magnetic
field whose total flux is half a quantum unit.Comment: 4 pages revtex, 4 figures + animation in multiframe GIF forma
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