A Layer-Stripping Method for 3D Near-Surface Velocity Model Building Using Seismic First-Arrival Times

In order to improve the efficiency of 3D near-surface velocity model building, we develop a layer-stripping method using seismic first-arrival times. The velocity model within a Common Mid-Point (CMP) ...     

Defining G protein-coupled receptor peptide ligand expressomes and signalomes in human and mouse islets

Introduction

Islets synthesise and secrete numerous peptides, some of which are known to be important regulators of islet function and glucose homeostasis. In this study, we quantified mRNAs encoding all peptide ligands of islet G protein-coupled receptors (GPCRs) in isolated human and mouse islets and carried out in vitro islet hormone secretion studies to provide functional confirmation for the species-specific role of peptide YY (PYY) in mouse islets.

Materials and methods

GPCR peptide ligand mRNAs in human and mouse islets were quantified by quantitative real-time PCR relative to the reference genes ACTB, GAPDH, PPIA, TBP and TFRC. The pathways connecting GPCR peptide ligands with their receptors were identified by manual searches in the PubMed, IUPHAR and Ingenuity databases. Distribution of PYY protein in mouse and human islets was determined by immunohistochemistry. Insulin, glucagon and somatostatin secretion from islets was measured by radioimmunoassay.

Results

We have quantified GPCR peptide ligand mRNA expression in human and mouse islets and created specific signalomes mapping the pathways by which islet peptide ligands regulate human and mouse GPCR signalling. We also identified species-specific islet expression of several GPCR ligands. In particular, PYY mRNA levels were ~ 40,000-fold higher in mouse than human islets, suggesting a more important role of locally secreted Pyy in mouse islets. This was confirmed by IHC and functional experiments measuring insulin, glucagon and somatostatin secretion.

Discussion

The detailed human and mouse islet GPCR peptide ligand atlases will allow accurate translation of mouse islet functional studies for the identification of GPCR/peptide signalling pathways relevant for human physiology, which may lead to novel treatment modalities of diabetes and metabolic disease.

     

An Economic Model-Based Matching Approach Between Buyers and Sellers Through a Broker in an Open E-Marketplace

A broker in an open e-marketplace enables buyers and sellers to do business with each other. Although a broker plays an important role in e-marketplaces, theory and guidelines for matching between buyers and sellers in multi-attribute exchanges are limited. Therefore, a challenge for a broker’s responsibility is how to maximize a buyer’s total satisfaction degree as its goals under the consideration of trade-off between a buyer’s buying quantity and price paid to a seller, and other attributes. To solve this challenge, this paper proposes an economic model-based matching approach between a buyer’s requirements and a seller’s offers. The major contributions of this paper are that (i) a broker can model a seller’s price policy as per a buyer’s buying quantity through communication between a broker and a seller; (ii) due to each buyer’s different quantity demand, a broker models a buyer’s satisfaction degree as per a buyer’s buying quantity based on communication between a broker and a buyer; and (iii) to carry out a broker’s matching processes, an objective function and a set of constraints are generated to help a broker to maximize a buyer’s total satisfaction degree. Experimental results demonstrate the good performance of the proposed approach.     

基于回转输运试验的煤散料离散元接触参数修正

为获取精确的刮板输送机离散元模拟结果，基于回转输运试验，通过响应面法对煤料的接触参数进行修正.采用Plackett-Burman试验考察接触参数对受力及堆积角的影响，发现煤-钢静摩擦系数、煤-煤摩擦系数具有显著正效应.根据爬坡试验结果，以受力及堆积角为响应值规划Box-Behnken试验，建立受力、堆积角与显著项间的二次回归多项式，以实测数据为目标值求得最佳参数:煤-钢静摩擦系数为0.401，煤-煤静摩擦系数为0.333，煤-煤滚动摩擦系数为0.041.通过不同输运条件下的回转试验验证了参数的准确性，为刮板输送机的离散元研究提供参考.     

部件寿命服从威布尔分布时典型系统的寿命与剩余寿命估计

在实际工程中,对系统寿命以及剩余寿命的估计非常重要。在已知系统中部件寿命与可靠度的前提下,关于如何快速得到系统级寿命与剩余寿命的相关研究比较缺乏。针对这一问题,首先研究了可靠度、寿命以及剩余寿命的关系,进一步假设部件寿命服从同一威布尔分布,根据部件的寿命与可靠度函数,推导得到串联、并联和表决系统寿命与剩余寿命期望的封闭表达式,并给出了相应的计算方法。对于冷备系统,当部件寿命服从同一指数分布时,推得了系统寿命及剩余寿命期望的封闭表达式,而当部件寿命服从同一威布尔分布时,给出了系统寿命与剩余寿命的数值计算方法。仿真试验证明本文所提出的方法是准确高效的。最后,以卫星中的动量轮r/n(G)表决系统为例开展了实例研究,证明了该方法在工程实践中的有效性。     

Hierarchical Community Detection Based on Partial Matrix Convergence Using Random Walks

Random walks are a standard tool for modeling the spreading process in social and biological systems.But in the face of large-scale networks,to achieve convergence,iterative calculation of the transition matrix in random walk methods consumes a lot of time.In this paper,we propose a three-stage hierarchical community detection algorithm based on Partial Matrix Approximation Convergence(PMAC) using random walks.First,this algorithm identifies the initial core nodes in a network by classical measurement and then utilizes the error function of the partial transition matrix convergence of the core nodes to determine the number of random walks steps.As such,the PMAC of the core nodes replaces the final convergence of all the nodes in the whole matrix.Finally,based on the approximation convergence transition matrix,we cluster the communities around core nodes and use a closeness index to merge two communities.By recursively repeating the process,a dendrogram of the communities is eventually constructed.We validated the performance of the PMAC by comparing its results with those of two representative methods for three real-world networks with different scales.     

Fuzzy Views on Black-Litterman Portfolio Selection Model

In this paper, views of investor are described in fuzzy sets, and two fuzzy Black-Litterman models are constructed with fuzzy views and fuzzy random views respectively. In the models, expected returns and uncertainty matrix of views are redefined and the views are formulated by fuzzy approaches suitably. Then the models are tested with data from Chinese financial markets. Empirical results show that the fuzzy random views model performs the best, and both the fuzzy models are better than the traditional ones, demonstrating that the fuzzy approaches can contain more information in the views and measure the uncertainty more correctly.     

等候区手术患者家属的心理影响因素及干预措施

目的:探讨等候区手术患者家属的心理影响因素及其干预措施.方法:通过临床护理实践及查阅相关文献进行总结分析.结果:影响因素及其干预措施包括详解病情及手术风险性;对手术环境及术中情况的告知;完善急诊手术患者家属心理干预;根据不同文化水平进行健康宣教;尽量以病情为主,设计最经济有效的治疗方案;提高医护人员从业技能及道德品质.结论:对等候区手术患者家属进行积极有效的心理干预,可很大程度上减轻患者家属的焦虑程度,缓和医患关系,一定程度上提升了医疗质量.     

数字量子模拟已经应用到两费米子体系了（英文）

In a recent work,a group of researchers led by Gui-Lu Long of Tsinghua University proposed a digital quantum simulation algorithm for the dynamics of interacting quantum systems in real space.They experimentally implemented the algorithm to simulate the dynamics of two interacting fermions using a nuclear magnetic resonance(NMR)setup[1].