897 research outputs found
Single-realization recovery of a random Schr\"odinger equation with unknown source and potential
In this paper, we study an inverse scattering problem associated with the
stationary Schr\"odinger equation where both the potential and the source terms
are unknown. The source term is assumed to be a generalised Gaussian random
distribution of the microlocally isotropic type, whereas the potential function
is assumed to be deterministic. The well-posedness of the forward scattering
problem is first established in a proper sense. It is then proved that the
rough strength of the random source can be uniquely recovered, independent of
the unknown potential, by a single realisation of the passive scattering
measurement. We develop novel techniques to completely remove a restrictive
geometric condition in our earlier study [25], at an unobjectionable cost of
requiring the unknown potential to be deterministic. The ergodicity is used to
establish the single realization recovery, and the asymptotic arguments in our
analysis are based on techniques from the theory of pseudo-differential
operators and the stationary phase principle.Comment: 28 page
Microsatellite Markers in the Mud Crab (Scylla paramamosain) and their Application in Population Genetics and Marker- Assisted Selection
The mud crab (Scylla paramamosain) is a commercially important species for aquaculture and fisheries in China. In this study, a total of 302 polymorphic microsatellite markers have been isolated and characterized. The observed and expected heterozygosity ranged from 0.04 to 1.00 and from 0.04 to 0.96 per locus. The wild populations distributed along South-eastern China coasts showed high genetic diversity (HO ranged from 0.62 to 0.77) and low genetic differentiation (FST = 0.018). Meanwhile, a significant association (r2 = 0.11) was identified between genetic and geographic distance of 11 locations. Furthermore, a PCR-based parentage assignment method was successfully developed using seven polymorphic microsatellite loci that could correctly assign 95% of the progeny to their parents. Moreover, three polymorphic microsatellite loci were identified to be significantly associated with 12 growth traits of S. paramamosain, and four genotypes were considered to be great potential for marker-assisted selection. Finally, a first preliminary genetic linkage map with 65 linkage groups and 212 molecular markers was constructed using microsatellite and AFLP markers for S. paramamosain. This map was 2746 cM in length, and covered approximately 50% of the estimated genome. This study provides novel insights into genome biology and molecular marker-assisted selection for S. paramamosain
Exact Transcript Quantification Over Splice Graphs
The probability of sequencing a set of RNA-seq reads can be directly modeled using the abundances of splice junctions in splice graphs instead of the abundances of a list of transcripts. We call this model graph quantification, which was first proposed by Bernard et al. (2014). The model can be viewed as a generalization of transcript expression quantification where every full path in the splice graph is a possible transcript. However, the previous graph quantification model assumes the length of single-end reads or paired-end fragments is fixed. We provide an improvement of this model to handle variable-length reads or fragments and incorporate bias correction. We prove that our model is equivalent to running a transcript quantifier with exactly the set of all compatible transcripts. The key to our method is constructing an extension of the splice graph based on Aho-Corasick automata. The proof of equivalence is based on a novel reparameterization of the read generation model of a state-of-art transcript quantification method. This new approach is useful for modeling scenarios where reference transcriptome is incomplete or not available and can be further used in transcriptome assembly or alternative splicing analysis
A Penalized Multi-trait Mixed Model for Association Mapping in Pedigree-based GWAS
In genome-wide association studies (GWAS), penalization is an important
approach for identifying genetic markers associated with trait while mixed
model is successful in accounting for a complicated dependence structure among
samples. Therefore, penalized linear mixed model is a tool that combines the
advantages of penalization approach and linear mixed model. In this study, a
GWAS with multiple highly correlated traits is analyzed. For GWAS with multiple
quantitative traits that are highly correlated, the analysis using traits
marginally inevitably lose some essential information among multiple traits. We
propose a penalized-MTMM, a penalized multivariate linear mixed model that
allows both the within-trait and between-trait variance components
simultaneously for multiple traits. The proposed penalized-MTMM estimates
variance components using an AI-REML method and conducts variable selection and
point estimation simultaneously using group MCP and sparse group MCP. Best
linear unbiased predictor (BLUP) is used to find predictive values and the
Pearson's correlations between predictive values and their corresponding
observations are used to evaluate prediction performance. Both prediction and
selection performance of the proposed approach and its comparison with the
uni-trait penalized-LMM are evaluated through simulation studies. We apply the
proposed approach to a GWAS data from Genetic Analysis Workshop (GAW) 18
Targeting of carbon ion-induced G2 checkpoint activation in lung cancer cells using Wee-1 inhibitor MK-1775
学位記番号:医博甲1572
Links Assignment Scheme based on Potential Edges Importance in Dual-layer Wavelength Routing Optical Satellite Networks
With the development of the massive satellite constellation and the on-orbit
laser-based communication equipment, the wavelength routing optical satellite
network (WROSN) becomes a potential solution for on-orbit, high-capacity, and
high-speed communication. Since the inter-satellite links (ISLs) are
time-varying, one of the fundamental considerations in the construction of the
WROSN is assigning limited laser communication terminals for each satellite to
establish ISLs with the visible satellites. Therefore, we propose a links
assignment scheme (LAS) based on the potential edges importance matrix (PEIM)
algorithm to construct a temporarily stable topology of the ISLs for a
dual-layer constellation. The simulation results showed that the LAS based on
the PEIM algorithm is better than LAS based on the random or Greedy algorithm
in terms of node-to-node distance, node pair connectivity, wavelength demand,
and transmission delay. The node pair connectivity and wavelength demand in
WROSN is a trade-off problem. The research in this paper also brings a novel
method for reduction of the cost of the on-board resources, that is through
designing topology of the ISLs with links assignment algorithm.Comment: This is the manuscript version that was submitted to the
International Journal of Satellite Communications and Networking
(SAT-23-0018
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