6,728 research outputs found
Providing Real-World Experiences: the Virginia Tech Externship for Mathematics Specialists
We describe the structure and implementation of the yearlong Externship experience associated with the Mathematics Specialist program at Virginia Polytechnic Institute & State University (Virginia Tech). We discuss the assignments and experiences included in the Externship, the alignment of those experiences with the job description developed by the Virginia Mathematics and Science Coalition Task Force, and teacher comments on the effectiveness of their Externship experiences [1]
Giotto Extended Mission (GEM)
The primary objectives of the Giotto Extended Mission (GEM), are to determine the composition and physical state of the Grigg Skjellerup Comet's nucleus; to determine the processes that govern the composition and distribution of neutral and ionized species in the cometary atmosphere. Giotto consists of a single European Space Agency (ESA) spacecraft that was launched in 1985 from Center Spatial Guyanis in French Guiana on an Ariane launch vehicle. After a successful launch into geostationary orbit and a heliocentric transfer trajectory, the spacecraft successfully encountered Halley's Comet in 1986. One month after encountering Halley's Comet, Mar. 1986, the spacecraft was placed in hibernation in a heliocentric orbit slightly less than 1 AU. Between Feb. and Jul. 1990 the spacecraft was successfully reactivated, checked out, and placed on a trajectory course to intercept comet Grigg Skjellerup. The spacecraft has been in hibernation since Jul. 1990. Information is presented in tabular form in the following areas: coverage goals, Deep Space Network Support, frequency assignments, telemetry, command, and tracking support responsibility
Management of the Rice Tungro Virus Vector \u3ci\u3eNephotettix virescens\u3c/i\u3e (Homoptera: Cicadellidae) with Controlled-Release Formulations of Carbofuran
Field trials were conducted in lowland flooded rice in the Philippines to evaluate a number of carbofuran controlled-release formulations in comparison with commercial formulations. The test formulations were based on a biodegradable matrix of pine kraft lignin and were used as granules of different sizes and also in the form of small strips. The release rates were assessed under field conditions by bioassaying rice plants in the field, using adult rice green leafhopper, Nephotettix virescens Distant. The lignin formulations with a high level of active ingredient (15–45% by weight) gave as good or better control than the commercial 3% granules in tests based on three application techniques: broadcast into the floodwater, soil incorporation, and root zone injection. The improvements in control levels of green leafhoppers were most marked with soil incorporation and root zone application. The best lignin-based formulation reduced levels of tungro virus infection from 23% for a conventional flowable carbofuran formulation to 1.0% at an application rate of 0.5 kg (AI)/ha. At the same rate, the grain yield was increased from 3.56 t/ha to 5.5 t/ha, using the controlled-released formulation
Image Processing Failure and Deep Learning Success in Lawn Measurement
Lawn area measurement is an application of image processing and deep
learning. Researchers have been used hierarchical networks, segmented images
and many other methods to measure lawn area. Methods effectiveness and accuracy
varies. In this project Image processing and deep learning methods has been
compared to find the best way to measure the lawn area. Three Image processing
methods using OpenCV has been compared to Convolutional Neural network which is
one of the most famous and effective deep learning methods. We used Keras and
TensorFlow to estimate the lawn area. Convolutional Neural Network or shortly
CNN shows very high accuracy (94-97%) for this purpose. In image processing
methods, Thresholding with 80-87% accuracy and Edge detection are effective
methods to measure the lawn area but Contouring with 26-31% accuracy does not
calculate the lawn area successfully. We may conclude that deep learning
methods especially CNN could be the best detective method comparing to image
processing and other deep learning techniques
Life inside black holes
We consider test planet and photon orbits of the third kind inside a black
hole, which are stable, periodic and neither come out of the black hole nor
terminate at the singularity. Interiors of supermassive black holes may be
inhabited by advanced civilizations living on planets with the third-kind
orbits. In principle, one can get information from the interiors of black holes
by observing their white hole counterparts.Comment: 4 pages, 2 figure
Inductive algebras and homogeneous shifts
Inductive algebras for the irreducible unitary representations of the
universal cover of the group of unimodular two by two matrices are classified.
The classification of homogeneous shift operators is obtained as a direct
consequence. This gives a new approach to the results of Bagchi and Misra
Disentangling multipole resonances through a full x-ray polarization analysis
Complete polarization analysis applied to resonant x-ray scattering at the Cr
K-edge in K2CrO4 shows that incident linearly polarized x-rays can be converted
into circularly polarized x-rays by diffraction at the Cr pre-edge (E = 5994
eV). The physical mechanism behind this phenomenon is a subtle interference
effect between purely dipole (E1-E1) and purely quadrupole (E2-E2) transitions,
leading to a phase shift between the respective scattering amplitudes. This
effect may be exploited to disentangle two close-lying resonances that appear
as a single peak in a conventional energy scan, in this way allowing to single
out and identify the different multipole order parameters involved.Comment: 6 pages, 6 figure
Influence of static Jahn-Teller distortion on the magnetic excitation spectrum of PrO2: A synchrotron x-ray and neutron inelastic scattering study
A synchrotron x-ray diffraction study of the crystallographic structure of
PrO2 in the Jahn-Teller distorted phase is reported. The distortion of the
oxygen sublattice, which was previously ambiguous, is shown to be a chiral
structure in which neighbouring oxygen chains have opposite chiralities. A
temperature dependent study of the magnetic excitation spectrum, probed by
neutron inelastic scattering, is also reported. Changes in the energies and
relative intensities of the crystal field transitions provide an insight into
the interplay between the static and dynamic Jahn-Teller effects.Comment: 7 pages, 6 figure
Comparison of charge modulations in LaBaCuO and YBaCuO
A charge modulation has recently been reported in (Y,Nd)BaCuO
[Ghiringhelli {\em et al.} Science 337, 821 (2013)]. Here we report Cu
edge soft x-ray scattering studies comparing the lattice modulation associated
with the charge modulation in YBaCuO with that associated with
the well known charge and spin stripe order in LaBaCuO.
We find that the correlation length in the CuO plane is isotropic in both
cases, and is \AA for LaBaCuO and \AA for YBaCuO. Assuming weak inter-planar correlations of
the charge ordering in both compounds, we conclude that the order parameters of
the lattice modulations in LaBaCuO and
YBaCuO are of the same order of magnitude.Comment: 3 pages, 2 figure
Rotated stripe order and its competition with superconductivity in LaSrCuO
We report the observation of a bulk charge modulation in
LaSrCuO (LSCO) with a characteristic in-plane wave-vector
of (0.236, ), with =0.011 r.l.u. The transverse shift of
the ordering wave-vector indicates the presence of rotated charge-stripe
ordering, demonstrating that the charge ordering is not pinned to the Cu-O bond
direction. On cooling through the superconducting transition, we find an abrupt
change in the growth of the charge correlations and a suppression of the charge
order parameter indicating competition between the two orderings. Orthorhombic
LSCO thus helps bridge the apparent disparities between the behavior previously
observed in the tetragonal "214" cuprates and the orthorhombic yttrium and
bismuth-based cuprates and thus lends strong support to the idea that there is
a common motif to charge order in all cuprate families.Comment: 6 pages, 4 figue
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