9,150 research outputs found
Graph Element Networks: adaptive, structured computation and memory
We explore the use of graph neural networks (GNNs) to model spatial processes
in which there is no a priori graphical structure. Similar to finite element
analysis, we assign nodes of a GNN to spatial locations and use a computational
process defined on the graph to model the relationship between an initial
function defined over a space and a resulting function in the same space. We
use GNNs as a computational substrate, and show that the locations of the nodes
in space as well as their connectivity can be optimized to focus on the most
complex parts of the space. Moreover, this representational strategy allows the
learned input-output relationship to generalize over the size of the underlying
space and run the same model at different levels of precision, trading
computation for accuracy. We demonstrate this method on a traditional PDE
problem, a physical prediction problem from robotics, and learning to predict
scene images from novel viewpoints.Comment: Accepted to ICML 201
Coherent absorption and enhanced photoluminescence in thin layers of nanorods
We demonstrate a large light absorptance (80%) in a nanometric layer of
quantum dots in rods (QRs) with a thickness of 23 nm. This behavior is
explained in terms of the coherent absorption by interference of the light
incident at a certain angle onto the very thin QR layer. We exploit this
coherent light absorption to enhance the photoluminescent emission from the
QRs. Up to a seven- and fivefold enhancement of the photoluminescence is
observed for p- and s-polarized incident light, respectively.Comment: Physical Review B 201
Updating Bounds on -Parity Violating Supersymmetry from Meson Oscillation Data
We update the bounds on -parity violating supersymmetry originating from
meson oscillations in the and systems. To this end, we
explicitly calculate all corresponding contributions from -parity violating
operators at the one-loop level, thereby completing and correcting existing
calculations. We apply our results to the derivation of bounds on -parity
violating couplings, based on up-to-date experimental measurements. In
addition, we consider the possibility of cancellations among flavor-changing
contributions of various origins, e.g. from multiple -parity violating
couplings or -parity conserving soft terms. Destructive interferences among
new-physics contributions could then open phenomenologically allowed regions,
for values of the parameters that are naively excluded when the parameters are
varied individually.Comment: 53 pages, 10 figures, 2 tables; final versio
The semantic effects of verb raising and its consequences in second language grammars
This article considers whether highly proficient second language speakers of English can distinguish meaning contrasts associated with constructions where there is a raising be, and constructions where there is a non-raising thematic verb, as illustrated in the difference between (1a) and (1b): 1a. Kim is reading a novel (`event-in-progress/existential ? interpretation
Genomic prediction and quantitative trait locus discovery in a cassava training population constructed from multiple breeding stages
Open Access Article; Published online: 11 Dec 2019Assembly of a training population (TP) is an important component of effective genomic selection‐based breeding programs. In this study, we examined the power of diverse germplasm assembled from two cassava (Manihot esculenta Crantz) breeding programs in Tanzania at different breeding stages to predict traits and discover quantitative trait loci (QTL). This is the first genomic selection and genome‐wide association study (GWAS) on Tanzanian cassava data. We detected QTL associated with cassava mosaic disease (CMD) resistance on chromosomes 12 and 16; QTL conferring resistance to cassava brown streak disease (CBSD) on chromosomes 9 and 11; and QTL on chromosomes 2, 3, 8, and 10 associated with resistance to CBSD for root necrosis. We detected a QTL on chromosome 4 and two QTL on chromosome 12 conferring dual resistance to CMD and CBSD. The use of clones in the same stage to construct TPs provided higher trait prediction accuracy than TPs with a mixture of clones from multiple breeding stages. Moreover, clones in the early breeding stage provided more reliable trait prediction accuracy and are better candidates for constructing a TP. Although larger TP sizes have been associated with improved accuracy, in this study, adding clones from Kibaha to those from Ukiriguru and vice versa did not improve the prediction accuracy of either population. Including the Ugandan TP in either population did not improve trait prediction accuracy. This study applied genomic prediction to understand the implications of constructing TP from clones at different breeding stages pooled from different locations on trait accuracy
Quantum Rod Emission Coupled to Plasmonic Lattice Resonances: A Collective Directional Source of Polarized Light
We demonstrate that an array of optical antennas may render a thin layer of
randomly oriented semiconductor nanocrystals into an enhanced and highly
directional source of polarized light. The array sustains collective plasmonic
lattice resonances which are in spectral overlap with the emission of the
nanocrystals over narrow angular regions. Consequently, different photon
energies of visible light are enhanced and beamed into definite directions.Comment: 4 pages, 3 figure
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