1,647 research outputs found
Water turbidity detection using ERTS-1 imagery
ERTS-1 images of two federal reservoirs in Kansas exhibit good correlation with suspended load. The major reservoirs in Kansas, as well as in other Great Plains states, are playing increasingly important roles in flood control, recreation, agriculture, and urban water supply. Satellite imagery may prove useful for acquiring timely low cost water quality data required for optimum management of these fresh water resources
Improved statistical learning abilities in adult bilinguals
Using multiple languages may confer distinct advantages in cognitive control, yet it is unclear whether bilingualism is associated with better implicit statistical learning, a core cognitive ability underlying language. We tested bilingual adults on a challenging task requiring simultaneous learning of two miniature grammars characterized by different statistics. We found that participants learned each grammar significantly better than chance and both grammars equally well. Crucially, a validated continuous measure of bilingual dominance predicted accuracy scores for both artificial grammars in a generalized linear model. The study thus demonstrates the first graded advantage in learning novel statistical relations in adult bilinguals
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Statistical learning bias predicts second-language reading efficiency
Statistical learning (SL) is increasingly invoked as a set of general-purpose mechanisms upon which language learning is built during infancy and childhood. Here we investigated the extent to which SL is related to adult language processing. In particular, we asked whether SL proclivities towards relations that are more informative of English are related to efficiency in reading English sentences by native speakers of Korean. We found that individuals with a stronger statistical learning sensitivity showed a larger effect of conditional word probability on word reading times, indicating that they more efficiently incorporated statistical regularities of the language during reading. In contrast, L2 English proficiency was related to overall reading speed but not to the use of statistical regularities
Is statistical learning trainable?
Statistical learning (SL) is the ability to implicitly extract regularities in the environment, and likely supports various
higher-order behaviors, from language to music and vision. While specific patterns experience are likely to influence SL outcomes, this ability is tacitly conceptualized as a fixed construct, and few studies to date have investigated how
experience may shape statistical learning. We report one experiment that directly tested whether SL can be modulated by previous experience. We used a prepost treatment design allowing us to pinpoint what specific
aspects of \u201cprevious experience\u201d matter for SL. The results show that performance on an artificial grammar learning task at post-test depends on whether the grammar to be learned at post-test matches the underlying grammar structures learned during treatment. Our study is the first to adopt a pre-post test design to directly modulate the effects of learning on learning itself
Electronic structure and chemical bonding of nc-TiC/a-C nanocomposites
The electronic structure of nanocrystalline (nc-) TiC/amorphous C
nanocomposites has been investigated by soft x-ray absorption and emission
spectroscopy. The measured spectra at the Ti 2p and C 1s thresholds of the
nanocomposites are compared to those of Ti metal and amorphous C. The
corresponding intensities of the electronic states for the valence and
conduction bands in the nanocomposites are shown to strongly depend on the TiC
carbide grain size. An increased charge-transfer between the Ti 3d-eg states
and the C 2p states has been identified as the grain size decreases, causing an
increased ionicity of the TiC nanocrystallites. It is suggested that the
charge-transfer occurs at the interface between the nanocrystalline TiC and the
amorphous C matrix and represents an interface bonding which may be essential
for the understanding of the properties of nc-TiC/amorphous C and similar
nanocomposites.Comment: 13 pages, 6 figures, 1 table;
http://link.aps.org/doi/10.1103/PhysRevB.80.23510
Magnetic circular dichroism in X-ray fluorescence of Heusler alloys at threshold excitation
The results of fluorescence measurements of magnetic circular dichroism (MCD)
in Mn L_2,L_3 X-ray emission and absorption for Heusler alloys NiMnSb and
Co2MnSb are presented. Very intense resonance Mn L_3 emission is found at the
Mn 2p_3/2 threshold and is attributed to a peculiarity of the threshold
excitation in materials with the half-metallic character of the electronic
structure. A theoretical model for the description of resonance scattering of
polarized x-rays is suggested.Comment: 3 pages, 2 figures. Discussed at conferences, submitting process in
progres
Large magnetic circular dichroism in resonant inelastic x-ray scattering at the Mn L-edge of Mn-Zn ferrite
We report resonant inelastic x-ray scattering (RIXS) excited by circularly
polarized x-rays on Mn-Zn ferrite at the Mn L2,3-resonances. We demonstrate
that crystal field excitations, as expected for localized systems, dominate the
RIXS spectra and thus their dichroic asymmetry cannot be interpreted in terms
of spin-resolved partial density of states, which has been the standard
approach for RIXS dichroism. We observe large dichroic RIXS at the L2-resonance
which we attribute to the absence of metallic core hole screening in the
insulating Mn-ferrite. On the other hand, reduced L3-RIXS dichroism is
interpreted as an effect of longer scattering time that enables spin-lattice
core hole relaxation via magnons and phonons occurring on a femtosecond time
scale.Comment: 7 pages, 2 figures,
http://link.aps.org/doi/10.1103/PhysRevB.74.17240
Bonding mechanism in the nitrides Ti2AlN and TiN: an experimental and theoretical investigation
The electronic structure of nanolaminate Ti2AlN and TiN thin films has been
investigated by bulk-sensitive soft x-ray emission spectroscopy. The measured
Ti L, N K, Al L1 and Al L2,3 emission spectra are compared with calculated
spectra using ab initio density-functional theory including dipole transition
matrix elements. Three different types of bond regions are identified; a
relatively weak Ti 3d - Al 3p bonding between -1 and -2 eV below the Fermi
level, and Ti 3d - N 2p and Ti 3d - N 2s bonding which are deeper in energy
observed at -4.8 eV and -15 eV below the Fermi level, respectively. A strongly
modified spectral shape of 3s states of Al L2,3 emission from Ti2AlN in
comparison to pure Al metal is found, which reflects the Ti 3d - Al 3p
hybridization observed in the Al L1 emission. The differences between the
electronic and crystal structures of Ti2AlN and TiN are discussed in relation
to the intercalated Al layers of the former compound and the change of the
materials properties in comparison to the isostructural carbides.Comment: 18 pages, 7 figures;
http://link.aps.org/doi/10.1103/PhysRevB.76.19512
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