109 research outputs found
Effect of Particle Spin on Trajectory Deflection and Gravitational Lensing
Spin of a test particle is a fundamental property that can affect its motion
in a gravitational field. In this work we consider the effect of particle spin
on its deflection angle and gravitational lensing in the equatorial plane of
arbitrary stationary and axisymmetric spacetimes. To do this we developed a
perturbative method that can be applied to spinning signals with arbitrary
asymptotic velocity and takes into account the finite distance effect of the
source and the observer. The deflection angle and total travel
time are expressed as (quasi-)power series whose coefficients are
polynomials of the asymptotic expansion coefficients of the metric functions.
It is found that when the spin and orbital angular momenta are parallel (or
antiparallel), the deflection angle is decreased (or increased). Apparent
angles of the images in gravitational lensing and their time delays
are also solved. In Kerr spacetime, spin affects the apparent angle
in a way similar to its effect on . The time delay between
signals with opposite spins is found to be proportional to the signal spin at
leading order. These time delays might be used to constrain the spin to mass
ratio of neutrinos.Comment: 33 pages, 7 figures, to match the published versio
Investigation of impact of shoreline alteration on coastal hydrodynamics using Dimension REduced Surrogate based Sensitivity Analysis
Stochastic Sampling for Efficient Seismic Risk Assessment of Transportation Network
For accurate seismic risk assessment of transportation network under probabilistic seismic hazard, the uncertainty in the seismic hazard, the damage states of links/bridges in the network, and network performance need to be quantified. Stochastic simulation is well suited for this task. However, it typically requires large number of model evaluations, which entails significant computational effort, especially for large network. To address the above challenges, an efficient stochastic sampling-based approach is proposed. It relies on generating one set of samples for earthquake magnitude and carrying out analysis for the corresponding set of networks. This set of evaluations are used for seismic risk assessment under different risk measures, different probabilistic seismic hazards (e.g., with or without considering spatial correlation), and also for risk-based importance ranking of all bridges/links in the network for risk mitigation purpose. No additional evaluation of the network model is needed. The proposed approach is applied to seismic risk assessment and mitigation of the transportation network of Los Angeles and Orange countries. The impact of spatial correlation in seismic hazard on the seismic risk assessment and mitigation is investigated
Fractal Evolution Characteristics on the Three-Dimensional Fractures in Coal Induced by CO2 Phase Transition Fracturing
To analyze the transformed effect of three-dimensional (3D) fracture in coal by CO2 phase
transition fracturing (CO2
-PTF), the CO2
-PTF experiment under a fracturing pressure of 185 MPa was
carried out. Computed Tomography (CT) scanning and fractal theory were used to analyze the 3D
fracture structure parameters. The fractal evolution characteristics of the 3D fractures in coal induced
by CO2
-PTF were analyzed. The results indicate that the CO2 phase transition fracturing coal has
the fracture generation effect and fracture expansion-transformation effect, causing the maximum
fracture length, fracture number, fracture volume and fracture surface area to be increased by 71.25%,
161.94%, 3970.88% and 1330.03%. The fractal dimension (DN) for fracture number increases from
2.3523 to 2.3668, and the fractal dimension (DV) for fracture volume increases from 2.8440 to 2.9040.
The early dynamic high-pressure gas jet stage of CO2
-PTF coal influences the fracture generation
effect and promotes the generation of 3D fractures with a length greater than 140 µm. The subsequent
quasi-static high-pressure gas stage influences the fracture expansion-transformation effect, which
promotes the expansion transformation of 3D fractures with a length of less than 140 µm. The
140 µm is the critical value for the fracture expansion-transformation effect and fracture generation
effect. Five indicators are proposed to evaluate the 3D fracture evolution in coal caused by CO2
-PTF,
which can provide theoretical and methodological references for the study of fracture evolution
characteristics of other unconventional natural gas reservoirs and their reservoir stimulation
SNP Assay Development for Linkage Map Construction, Anchoring Whole-Genome Sequence, and Other Genetic and Genomic Applications in Common Bean.
A total of 992,682 single-nucleotide polymorphisms (SNPs) was identified as ideal for Illumina Infinium II BeadChip design after sequencing a diverse set of 17 common bean (Phaseolus vulgaris L) varieties with the aid of next-generation sequencing technology. From these, two BeadChips each with >5000 SNPs were designed. The BARCBean6K_1 BeadChip was selected for the purpose of optimizing polymorphism among market classes and, when possible, SNPs were targeted to sequence scaffolds in the Phaseolus vulgaris 14× genome assembly with sequence lengths >10 kb. The BARCBean6K_2 BeadChip was designed with the objective of anchoring additional scaffolds and to facilitate orientation of large scaffolds. Analysis of 267 F2 plants from a cross of varieties Stampede × Red Hawk with the two BeadChips resulted in linkage maps with a total of 7040 markers including 7015 SNPs. With the linkage map, a total of 432.3 Mb of sequence from 2766 scaffolds was anchored to create the Phaseolus vulgaris v1.0 assembly, which accounted for approximately 89% of the 487 Mb of available sequence scaffolds of the Phaseolus vulgaris v0.9 assembly. A core set of 6000 SNPs (BARCBean6K_3 BeadChip) with high genotyping quality and polymorphism was selected based on the genotyping of 365 dry bean and 134 snap bean accessions with the BARCBean6K_1 and BARCBean6K_2 BeadChips. The BARCBean6K_3 BeadChip is a useful tool for genetics and genomics research and it is widely used by breeders and geneticists in the United States and abroad
Secure Source-Relay Link Based Threshold DF Relaying Scheme
In this work, a dual-hop cooperative system, in which there are a Source-Destination (S-D) pair, a relay node (R) and an eavesdropper (E), which attempts to eavesdrop the confidential message sent by S and forwarded by R, is considered. In order to enhance the system performance and save the system resource, we propose an S - R link based threshold decode-and-forward (DF) relaying scheme for R to decide whether to aid S-D pair’s information transmission or not, other than the traditional DF relaying scheme. The secrecy outage performance of the considered system is investigated and the closed-form analytical expression for secrecy outage probability is derived and verified via Monte-Carlo simulations
On indoor visible light communication systems with spatially random receiver
This paper studies the performance of an indoor optical wireless communication system with visible light communication (VLC) technology in a cuboid room with a spatially random receiver. Considering that the receiver is uniformly distributed on the floor of a 4a m x 4b m x H m (where a > 0, b > 0 and H > 0) cuboid room, 4 light emitting diode (LED) lamps are all located at the center of 2a m x 2b m rectangle, which is a quarter of the ceiling area. The receiver chooses the best channel link to receive the information from the LED lamps, which depends on the distance between the receiver and each lamp. By using stochastic geometry theory, we derive the exact/approximated analytical expressions for the outage probability and the ergodic capacity, respectively. Finally, our derived analytical results are verified by Monte Carlo simulations
Indeterminate pulmonary subsolid nodules in patients with no history of cancer: growing prediction, CT pattern, and pathological diagnosis
PURPOSEWe aimed to evaluate and compare the growth patterns among pathological types of inde- terminate subsolid nodules in patients without a history of cancer as observed on computed tomography (CT).METHODSThis retrospective study included 77 consecutive patients with 80 indeterminate subsolid nod- ules on unenhanced thin-section CT. Subsolid nodules were classified into 2 growth pattern groups based on volume: growth (n = 35) and non-growth (n = 42). According to the pathologi- cal diagnosis, subsolid nodules were further subdivided into 3 groups: adenocarcinoma in situ (growth, n = 8 vs. non-growth, n = 22), minimally invasive adenocarcinoma (n = 14 vs. n = 15), and invasive adenocarcinoma (n=13 vs. n=5). Kaplan–Meier and Cox proportional hazards regres- sion analyses were performed to identify the risk factors for subsolid nodules growth. The CT findings of the 35 subsolid nodules in the growth group were compared among the 3 pathologi- cal groups.RESULTSIn the growth group, the overall mean volume doubling time and mass doubling time (MDT) were 811.5 days and 616.5 days, respectively. Patient’s age (odds ratio=1.041, P=.045) and CT subtype of non-solid nodule and part-solid nodule (odds ratio=3.430, P=.002) could predict subsolid nodule growth. The baseline volume, mass, and mean CT value were larger in the inva- sive adenocarcinoma group than in the adenocarcinoma in situ group (all P < .01). The shortest volume doubling time was observed in the invasive adenocarcinoma group, followed by the minimally invasive adenocarcinoma group and the adenocarcinoma in situ group. A shorter mass doubling time was observed in the minimally invasive adenocarcinoma group than in the adenocarcinoma in situ group (all P < .02).CONCLUSIONAs age increases, the risk of pulmonary subsolid nodule growth increases by 4% each year, and part-solid nodules have a 3 times higher risk of growth compared to non-solid nodules in patients with no history of cancer. Subsolid nodules with more aggressive pathological charac- teristics grow at a faster rate
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