1,476 research outputs found
STG2Seq: Spatial-temporal Graph to Sequence Model for Multi-step Passenger Demand Forecasting
Multi-step passenger demand forecasting is a crucial task in on-demand
vehicle sharing services. However, predicting passenger demand over multiple
time horizons is generally challenging due to the nonlinear and dynamic
spatial-temporal dependencies. In this work, we propose to model multi-step
citywide passenger demand prediction based on a graph and use a hierarchical
graph convolutional structure to capture both spatial and temporal correlations
simultaneously. Our model consists of three parts: 1) a long-term encoder to
encode historical passenger demands; 2) a short-term encoder to derive the
next-step prediction for generating multi-step prediction; 3) an
attention-based output module to model the dynamic temporal and channel-wise
information. Experiments on three real-world datasets show that our model
consistently outperforms many baseline methods and state-of-the-art models.Comment: 7 page
Analysis of genetic diversity and construction of core collection of local mulberry varieties from Shanxi Province based on ISSR marker
Genetic diversity of 73 local mulberry varieties from Shanxi Province were screened using ISSR markers, with l5 primers combinations selected for their reproducibility and polymorphism. 129 bands were amplified, of which 115 bands showed polymorphism and the ratio of polymorphism bands was 89.15%. Nei’s genetic similarity coefficients ranged from 0.5891 to 0.9457 with an average of 0.7674. The observed number of alleles of each loci, effective number of alleles of each loci, Nei’s gene diversity, Shannon’s information index were 1.8915, 1.4771, 0.2780 and 0.4197, respectively. Clustering results showed that the 73 varieties could be divided into three different groups and nine subgroups. By using stepwise clustering and random methods and the modified heuristic algorithm, 21 core collections were constructed and the ratio of core collection was 28.77%. The result of t-test to the parameters (the number effective of alleles, Nei's genetic diversity index and Shannon's information index) showed that there was not significant difference between the core collection and initial sample with the exception of the number of observed alleles, that is, the core collection could well represent the initial sample.Key words: Mulberry, germplasm resource, genetic diversity, ISSR, cluster analysis, core collection
The topological AC effect on noncommutative phase space
The Aharonov-Casher (AC) effect in non-commutative(NC) quantum mechanics is
studied. Instead of using the star product method, we use a generalization of
Bopp's shift method. After solving the Dirac equations both on noncommutative
space and noncommutative phase space by the new method, we obtain the
corrections to AC phase on NC space and NC phase space respectively.Comment: 8 pages, Latex fil
Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean
Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants that
can be transferred long distances and tend to accumulate in marine sediments.
However, less is known regarding the distribution of PAHs and their natural
bioattenuation in the open sea, especially the Arctic Ocean. In this report,
sediment samples were collected at four sites from the Chukchi Plateau to the
Makarov Basin in the summer of 2010. PAH compositions and total
concentrations were examined with GC-MS. The concentrations of 16
EPA-priority PAHs varied from 2.0 to 41.6 ng g−1 dry weight and
decreased with sediment depth and movement from the southern to the northern
sites. Among the targeted PAHs, phenanthrene was relatively abundant in all
sediments. The 16S rRNA gene of the total environmental DNA was analyzed with
Illumina high-throughput sequencing (IHTS) to determine the diversity of
bacteria involved in PAH degradation in situ. The potential degraders
including Cycloclasticus, Pseudomonas, Halomonas,
Pseudoalteromonas, Marinomonas, Bacillus,
Dietzia, Colwellia, Acinetobacter,
Alcanivorax, Salinisphaera and Shewanella, with
Dietzia as the most abundant, occurred in all sediment samples.
Meanwhile, enrichment with PAHs was initiated onboard and transferred to the
laboratory for further enrichment and to obtain the degrading consortia. Most
of the abovementioned bacteria in addition to Hahella, Oleispira,
Oceanobacter and Hyphomonas occurred alternately as predominant
members in the enrichment cultures from different sediments based on IHTS and
PCR-DGGE analysis. To reconfirm their role in PAH degradation, 40 different
bacteria were isolated and characterized, among which Cycloclasticus
Pseudomonas showed the best degradation capability under low
temperatures. Taken together, PAHs and PAH-degrading bacteria were widespread
in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of
Cycloclasticus, Pseudomonas, Pseudoalteromonas,
Halomonas, Marinomonas and Dietzia may play the
most important role in PAH mineralization in situ
The HMW effect in Noncommutative Quantum Mechanics
The HMW effect in non-commutative quantum mechanics is studied. By solving
the Dirac equations on non-commutative (NC) space and non-commutative phase
space, we obtain topological HMW phase on NC space and NC phase space
respectively, where the additional terms related to the space-space and
momentum-momentum non-commutativity are given explicitly.Comment: 8 Latex page
Properties and Performance of Two Wide Field of View Cherenkov/Fluorescence Telescope Array Prototypes
A wide field of view Cherenkov/fluorescence telescope array is one of the
main components of the Large High Altitude Air Shower Observatory project. To
serve as Cherenkov and fluorescence detectors, a flexible and mobile design is
adopted for easy reconfiguring of the telescope array. Two prototype telescopes
have been constructed and successfully run at the site of the ARGO-YBJ
experiment in Tibet. The features and performance of the telescopes are
presented
\psi(2S) Decays into \J plus Two Photons
Using \gamma \gamma J/\psi, J/\psi \ra e^+ e^- and events
from a sample of \psip decays collected with the BESII
detector, the branching fractions for \psip\ra \pi^0\J, \eta\J, and
\psi(2S)\ar\gamma\chi_{c1},\gamma\chi_{c2}\ar\gamma\gamma\jpsi are measured
to be B(\psip\ra \pi^0\J) = (1.43\pm0.14\pm0.13)\times 10^{-3}, B(\psip\ra
\eta\J) = (2.98\pm0.09\pm0.23)%,
B(\psi(2S)\ar\gamma\chi_{c1}\ar\gamma\gamma\jpsi) = (2.81\pm0.05\pm 0.23)%,
and B(\psi(2S)\ar\gamma\chi_{c2}\ar\gamma\gamma\jpsi) = (1.62\pm0.04\pm
0.12)%.Comment: 7 pages, 6 figures. submitted to Phys. Rev.
First Measurement of the Branching Ratio of
Using 58 million events taken with the BES II detector at the
Beijing Electron Positron Collider, a new decay mode is observed for the
first time. The branching ratio is determined to be , where the quoted
errors are statistical and systematic, respectively.Comment: 7 pages, 3 figure
Measurements of decays into Vector- Tensor final states
Decays of the into vector plus tensor meson final states have been
studied with 14 million events collected with the BESII detector.
Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ,
and are
determined. They improve upon previous BESI results and confirm the violation
of the "12%" rule for decays to VT channels with higher precision.Comment: 7 pages, 7 figures and 2 table
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