82 research outputs found
A Time-Dependent Fuzzy Programming Approach for the Green Multimodal Routing Problem with Rail Service Capacity Uncertainty and Road Traffic Congestion
This study explores an operational-level container routing problem in the road-rail multimodal service network. In response to
the demand for an environmentally friendly transportation, we extend the problem into a green version by using both
emission charging method and bi-objective optimization to optimize the CO2 emissions in the routing. Two uncertain
factors, including capacity uncertainty of rail services and travel time uncertainty of road services, are formulated in order
to improve the reliability of the routes. By using the triangular fuzzy numbers and time-dependent travel time to separately
model the capacity uncertainty and travel time uncertainty, we establish a fuzzy chance-constrained mixed integer nonlinear
programming model. A linearization-based exact solution strategy is designed, so that the problem can be effectively solved
by any exact solution algorithm on any mathematical programming software. An empirical case is presented to demonstrate
the feasibility of the proposed methods. In the case discussion, sensitivity analysis and bi-objective optimization analysis are
used to find that the bi-objective optimization method is more effective than the emission charging method in lowering the
CO2 emissions for the given case. Then, we combine sensitivity analysis and fuzzy simulation to identify the best
confidence value in the fuzzy chance constraint. All the discussion will help decision makers to better organize the green
multimodal transportation
STDA-Meta: A Meta-Learning Framework for Few-Shot Traffic Prediction
As the development of cities, traffic congestion becomes an increasingly
pressing issue, and traffic prediction is a classic method to relieve that
issue. Traffic prediction is one specific application of spatio-temporal
prediction learning, like taxi scheduling, weather prediction, and ship
trajectory prediction. Against these problems, classical spatio-temporal
prediction learning methods including deep learning, require large amounts of
training data. In reality, some newly developed cities with insufficient
sensors would not hold that assumption, and the data scarcity makes predictive
performance worse. In such situation, the learning method on insufficient data
is known as few-shot learning (FSL), and the FSL of traffic prediction remains
challenges. On the one hand, graph structures' irregularity and dynamic nature
of graphs cannot hold the performance of spatio-temporal learning method. On
the other hand, conventional domain adaptation methods cannot work well on
insufficient training data, when transferring knowledge from different domains
to the intended target domain.To address these challenges, we propose a novel
spatio-temporal domain adaptation (STDA) method that learns transferable
spatio-temporal meta-knowledge from data-sufficient cities in an adversarial
manner. This learned meta-knowledge can improve the prediction performance of
data-scarce cities. Specifically, we train the STDA model using a
Model-Agnostic Meta-Learning (MAML) based episode learning process, which is a
model-agnostic meta-learning framework that enables the model to solve new
learning tasks using only a small number of training samples. We conduct
numerous experiments on four traffic prediction datasets, and our results show
that the prediction performance of our model has improved by 7\% compared to
baseline models on the two metrics of MAE and RMSE
Xiao-Shen-Formula, a Traditional Chinese Medicine, Improves Glomerular Hyper-Filtration in Diabetic Nephropathy via Inhibiting Arginase Activation and Heparanase Expression
Hyperglycemia induces glomerular hyper-filtration, which contributes to the development of diabetic nephropathy (DN), a condition that remains a challenge for treatment. The present study investigated the effect of Xiao-Shen-Formula (XSF) used for treatment of renal injury in type 1 DN mice model induced by streptozotocin (STZ) and its underlying mechanism in cultured human glomerular endothelial cell (hGECs). Studies were performed using control, diabetic DN, DN treated with XSF groups (1 g/kg/d, LXSF or 3 g/kg/d, HXSF) for 6 weeks and hGECs were post-treated with mice serum containing HXSF (MS-HXSF) and arginase inhibitor (ABH, 100 μM) in high glucose medium. HXSF treatment restored STZ-induced renal hyper-filtration, glomerulosclerosis, renal microvascular remodeling and the increased levels of systemic reactive oxidative species and inflammatory cytokines, accompanied by preventing the decreased expression of glomerular heparin sulfate and the increased levels of cortical heparanase and argianse2 protein and arginase activity. In hGECs study, MS-HXSF ameliorated the enhancement in arginase activity, the protein/mRNA expression of heparanase, mRNA levels of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and permeability of hGECs monolayers as well as the depression of nitric oxide production. Besides all these protective effects, XSF blunted the mRNA expression of TNF-α in vivo and vitro studies as well, which was not changed by the post-treatment of ABH or HXSF plus ABH. This study demonstrated that the protective effect of XSF might be related with vascular prevention, anti-inflammation and anti-oxidation through intervening multi-targets including glomerular endothelial arginase-heparanase signaling pathway in DN model
An Empirical Study on the Comprehensive Optimization Method of a Train Diagram of the China High Speed Railway Express
The rapid and stable development of China’s economy has driven the increasing demand for express transportation. Based on network operation, China Railway Corporation of High-speed Railway launched high-speed rail products, which have attracted wide attention from all walks of life. With the application of high-speed express trains, the market structure of express transportation in China will change dramatically, from highways as the main mode of transportation to high-speed railway transportation relying on a high-speed railway network, which will effectively reduce the environmental pollution caused by express transportation and further improve the sustainable development of the economy and the logistics industry. At present, the freight Electric Multiple Units (EMU) has been successfully developed and has entered the final test stage. In the last paper, we have introduced the theory and method of the high-speed rail express train operation plan. In addition, a train diagram is an important foundation of railway transportation organization. In order to ensure the sustainable development of high-speed rail express trains after they are put into use, based on the operation plan of high-speed rail express trains, this paper establishes a comprehensive compilation model of a high-speed rail express train diagram, considering train running time, freight flow distribution scheme, and the operation plan of freight multiple units, and an exact solution algorithm based on the Lagrange relaxation algorithm is designed. The computational results are encouraging and demonstrate the effectiveness of the model and solution method.
Document type: Articl
Mutational Analysis of Highly Conserved Residues in the Phage PhiC31 Integrase Reveals Key Amino Acids Necessary for the DNA Recombination
Background: Amino acid sequence alignment of phage phiC31 integrase with the serine recombinases family revealed highly conserved regions outside the catalytic domain. Until now, no system mutational or biochemical studies have been carried out to assess the roles of these conserved residues in the recombinaton of phiC31 integrase. Methodology/Principal Findings: To determine the functional roles of these conserved residues, a series of conserved residues were targeted by site-directed mutagenesis. Out of the 17 mutants, 11 mutants showed impaired or no recombination ability, as analyzed by recombination assay both in vivo and in vitro. Results of DNA binding activity assays showed that mutants (R18A, I141A, L143A,E153A, I432A and V571A) exhibited a great decrease in DNA binding affinity, and mutants (G182A/F183A, C374A, C376A/G377A, Y393A and V566A) had completely lost their ability to bind to the specific target DNA attB as compared with wild-type protein. Further analysis of mutants (R18A, I141A, L143A and E153A) synapse and cleavage showed that these mutants were blocked in recombination at the stage of strand cleavage. Conclusions/Significance: This data reveals that some of the highly conserved residues both in the N-terminus and C-terminus region of phiC31 integrase, play vital roles in the substrate binding and cleavage. The cysteine-rich motif and th
Hydrological Changes Related to ENSO-Like States During the Last Deglaciation in Central Eastern China
Present knowledge of hydrological changes in the East Asian summer monsoon region during the last deglaciation lacks precision, most especially for central eastern China. A hydrological reconstruction based on elemental ratios, such as Rubidium/Strontium (Rb/Sr) and Zirconium/Rubidium (Zr/Rb), and grain-size distribution for the period of 22.8–7.4 ka was derived from the Dajiuhu basin in central eastern China. The reconstruction shows that there were some small wet-dry fluctuations within the basin between 22.8 and 17.5 ka, but an abrupt wetting after 17.5 ka, with a maximum occurring around 15.0 ka, then a drying trend until the early Holocene. This pattern parallels the zonal gradient of sea surface temperature (SST) across the tropical Pacific, which suggests that wet conditions in the Dajiuhu basin respond to the decreased SST zonal gradient. A marked decrease in the tropical Pacific SST zonal gradient, seen as an El Niño-like state, could lead to an anomalous anticyclonic circulation at the Western Pacific and a southward excursion of the Western Pacific Subtropical High, which favors the occurrence of wet conditions in central eastern China. Meanwhile, this El Niño-like state could sharpen the SST meridional gradient between the tropics and the extratropics, and then shift the upper tropospheric westerlies southward, which in turn induces a prolonged Mei-yu and more precipitation in central eastern China. Overall, it is concluded that the El Niño-Southern Oscillation-like states might be a major forcing for hydrological changes in central eastern China during the last deglaciation
Local Vibrational Modes Competitions in Mn-Doped ZnO Epitaxial Films with Tunable Ferromagnetism
We reported spectroscopic investigations of high quality Mn-doped ZnO (ZnMnO) films grown by oxygen plasma-assisted molecular beam epitaxy. Raman scattering spectra revealed two local vibrational modes (LVMs) associated with Mn dopants at 523 and 712cm-1. The LVMs and magnetic properties of ZnMnO films can be synchronously modulated by post annealing processing or by introducing tiny Co. The relative intensity of two LVMs clearly shows competitions arising from uncompensated acceptor and donor defects competition for ferromagnetic and nonmagnetic films. The experimental results indicated that LVM at 523 cm-1 is attributed to Mn—(Zinc-vacancy) complexes, while LVM at 712 cm-1 is attributed to Mn—(Oxygen-vacancy) complexes
An Empirical Study on the Comprehensive Optimization Method of a Train Diagram of the China High Speed Railway Express
The rapid and stable development of China’s economy has driven the increasing demand for express transportation. Based on network operation, China Railway Corporation of High-speed Railway launched high-speed rail products, which have attracted wide attention from all walks of life. With the application of high-speed express trains, the market structure of express transportation in China will change dramatically, from highways as the main mode of transportation to high-speed railway transportation relying on a high-speed railway network, which will effectively reduce the environmental pollution caused by express transportation and further improve the sustainable development of the economy and the logistics industry. At present, the freight Electric Multiple Units (EMU) has been successfully developed and has entered the final test stage. In the last paper, we have introduced the theory and method of the high-speed rail express train operation plan. In addition, a train diagram is an important foundation of railway transportation organization. In order to ensure the sustainable development of high-speed rail express trains after they are put into use, based on the operation plan of high-speed rail express trains, this paper establishes a comprehensive compilation model of a high-speed rail express train diagram, considering train running time, freight flow distribution scheme, and the operation plan of freight multiple units, and an exact solution algorithm based on the Lagrange relaxation algorithm is designed. The computational results are encouraging and demonstrate the effectiveness of the model and solution method
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