31,400 research outputs found
Regional mapping of the crustal structure in southern California from receiver functions
Lateral variations of the crustal structure in southern California are determined from receiver function (RF) studies using data from the Southern California Seismic Network broadband stations and Los Angeles Regional Seismic Experiment surveys. The results include crustal thickness estimates at the stations themselves, and where possible, cross sections are drawn. The large-scale Moho depth variation pattern generally correlates well with the current status of the Mesozoic batholith: Deep Moho of 35–39 km is observed beneath the western Peninsula Ranges, Sierra Nevada, and San Bernardino Mountains, where the batholith is relatively intact, and shallow Moho of 26–32 km is observed in the Mojave Desert, where the batholith is highly deformed and disrupted. High-resolution lateral variations of the crustal structure for individual geographic provinces are investigated, and distinctive features are identified. The crustal structure is strongly heterogeneous beneath the central Transverse Ranges, and deep Moho of 36–39 km is locally observed beneath several station groups in the western San Gabriel Mountains. Moho is relatively flat and smooth beneath the western Mojave Desert but gets shallower and complicated to the east. Anomalous RFs are observed at two stations in the eastern Mojave Desert, where a Moho step of ∼8–10 km is found between the NW and SE back-azimuthal groups of station DAN in the Fenner Valley. Asymmetric extension of the Salton Trough is inferred from the Moho geometry. Depth extension of several major faults, such as the San Andreas Fault and San Gabriel Fault, to the Moho is inferred
Transmutation prospect of long-lived nuclear waste induced by high-charge electron beam from laser plasma accelerator
Photo-transmutation of long-lived nuclear waste induced by high-charge
relativistic electron beam (e-beam) from laser plasma accelerator is
demonstrated. Collimated relativistic e-beam with a high charge of
approximately 100 nC is produced from high-intensity laser interaction with
near-critical-density (NCD) plasma. Such e-beam impinges on a high-Z convertor
and then radiates energetic bremsstrahlung photons with flux approaching
10^{11} per laser shot. Taking long-lived radionuclide ^{126}Sn as an example,
the resulting transmutation reaction yield is the order of 10^{9} per laser
shot, which is two orders of magnitude higher than obtained from previous
studies. It is found that at lower densities, tightly focused laser irradiating
relatively longer NCD plasmas can effectively enhance the transmutation
efficiency. Furthermore, the photo-transmutation is generalized by considering
mixed-nuclide waste samples, which suggests that the laser-accelerated
high-charge e-beam could be an efficient tool to transmute long-lived nuclear
waste.Comment: 13 pages, 8 figures, it has been submitted to Physics of Plasm
Deep Multi-instance Networks with Sparse Label Assignment for Whole Mammogram Classification
Mammogram classification is directly related to computer-aided diagnosis of
breast cancer. Traditional methods rely on regions of interest (ROIs) which
require great efforts to annotate. Inspired by the success of using deep
convolutional features for natural image analysis and multi-instance learning
(MIL) for labeling a set of instances/patches, we propose end-to-end trained
deep multi-instance networks for mass classification based on whole mammogram
without the aforementioned ROIs. We explore three different schemes to
construct deep multi-instance networks for whole mammogram classification.
Experimental results on the INbreast dataset demonstrate the robustness of
proposed networks compared to previous work using segmentation and detection
annotations.Comment: MICCAI 2017 Camera Read
Coherent Microwave Control of Ultracold NaK Molecules
We demonstrate coherent microwave control of rotational and hyperfine states
of trapped, ultracold, and chemically stable NaK molecules.
Starting with all molecules in the absolute rovibrational and hyperfine ground
state, we study rotational transitions in combined magnetic and electric fields
and explain the rich hyperfine structure. Following the transfer of the entire
molecular ensemble into a single hyperfine level of the first rotationally
excited state, , we observe collisional lifetimes of more than , comparable to those in the rovibrational ground state, . Long-lived
ensembles and full quantum state control are prerequisites for the use of
ultracold molecules in quantum simulation, precision measurements and quantum
information processing.Comment: 5 pages, 4 figure
A parity-breaking electronic nematic phase transition in the spin-orbit coupled metal CdReO
Strong electron interactions can drive metallic systems toward a variety of
well-known symmetry-broken phases, but the instabilities of correlated metals
with strong spin-orbit coupling have only recently begun to be explored. We
uncovered a multipolar nematic phase of matter in the metallic pyrochlore
CdReO using spatially resolved second-harmonic optical anisotropy
measurements. Like previously discovered electronic nematic phases, this
multipolar phase spontaneously breaks rotational symmetry while preserving
translational invariance. However, it has the distinguishing property of being
odd under spatial inversion, which is allowed only in the presence of
spin-orbit coupling. By examining the critical behavior of the multipolar
nematic order parameter, we show that it drives the thermal phase transition
near 200 kelvin in CdReO and induces a parity-breaking lattice
distortion as a secondary order.Comment: 9 pages main text, 4 figures, 10 pages supplementary informatio
Recombination between Fusarium oxysporum telomeres and pUC ampicillin resistance gene in a transforming vector.
Transformations using certain vector/host combinations of Fusarium oxysporum have been shown to promote in vivo production of linear, autonomously replicating plasmids (Powell and Kistler, 1990, J. Bact. 172:3163-3171). The modifications to the transforming vector included: linearization of a circular plasmid, addition of putative fungal telomeres to one end of the plasmid, and duplication and translocation of the modified DNA to the other end of the plasmid. This report confirms that the putative telomere repeats (TTAGGG) from one of these fungal-modified vectors, pFOLT4R4, are also located at the ends of F. oxysporum chromosomes and indicates that these telomere sequences were added to the vector by a recombinational event
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