基于无条件分位回归的民营上市公司高管薪酬问题研究

高级管理人员的薪酬作为现代企业委托代理关系中的核心问题一直是社会的焦点.本文以我国民营上市公司为样本,首先研究了公司规模、每股收益、营业收入、流动负债和高管持股比例作用于高管薪酬不同分位点处的条件分位偏效应,结果表明它们在不同分位水平下的影响各异;然后为了获得这些因素的一般边际影响,利用无条件分位回归分析了它们的无条件分位偏效应,结果指出公司规模、每股收益和营业收入与各个分位水平的高管薪酬呈不同程度的正相关而流动负债则为负相关,高管持股比例与低分位水平的高管薪酬正相关而对中高分位水平的影响不显著;最后对相关结果进行了对比,发现每个影响因素的条件和无条件分位偏效应有所区别,并且无条件分位偏效应的解释意义更具有现实价值.     

一类含参半正二阶离散周期边值问题正解的存在性

用Guo-Krasnoselskii不动点定理给出半正二阶离散周期边值问题正解的存在性和多解性结果, 其中λ>0为参数, ［1,T］_z={1,2,…,T}, f: ［1,T］_z×［0,∞)→R连续且存在常数D>0, 使得f(t,u)≥-D, (t,u)∈［1,T］_z×［0,∞), a: ［1,T］_z→(0,∞), 02(π/2T).     

Multifunctional artificial nacre via biomimetic matrix-directed mineralization

Natural nacre, one of the most studied biological structural materials with delicate hierarchical structures and extraordinary performance, has inspired the design and fabrication of artificial structural ceramics with high fracture toughness. However, to meet the diverse requirements of different applications, future structural materials must be multifunctional with superior mechanical properties, such as strength, hardness, and toughness. Herein, based on the matrix-directed mineralization method for producing biomimetic structural materials, we introduce nanoparticles with different inherent functions into the platelets of artificial nacre via the co-mineralization of aragonite and the nanoparticles. Besides their enhanced mechanical properties, the obtained artificial nacre materials also exhibit different functions depending on the type of the nanoparticles. To extend the versatility of this strategy, the effects of nanoparticles of different sizes and zeta potentials on mineralization are also analyzed. This universal strategy can be applied to the fabrication of other types of functionalized biomimetic structural ceramics that have potential applications in various fields, such as biomedical science.     

Evolutionary game analysis of low-carbon behavior credit supervision of logistics enterprises

Based on the low-carbon obligation fulfillment of Chinese logistics enterprises, this study constructs a tripartite evolutionary game model to analyze the evolutionary process of the interaction between the local government, logistics enterprises and the public in the process of low-carbon behavior credit supervision. Then using Netlogo software, a parameter simulation experiment is conducted to determine the optimal policy for improving the effect of supervision. The results are as follows: ① The combined influence of the local government and the public can effectively change the strategic choice of enterprises and promote the low-carbon behavior of enterprises. ② In terms of improving the effect of supervision, reducing the cost of government supervision would have a highly significant effect, and reducing the cost of the public would be counterproductive. ③ Increasing the government subsidies to enterprises and the government’s fines to enterprises both have a significant effect, and the effect of improving the former is better. However, increasing the severity of higher-level governments punishing local governments will reduce the stability of the system. ④ Supervision can be more effective by increasing the public’s impact on enterprises’ earnings rather than by increasing government subsidies to the public.     

基于动态博弈的补贴模式对机场群航线网络结构的影响研究

为探讨不同补贴模式对机场群航线网络结构的影响，本文构建了关于机场、航空公司和乘客之间的动态博弈模型，通过逆向归纳法得到了纳什均衡条件. 研究结果发现：（1）不同的补贴模式对多机场航线网络结构产生重要影响，低补贴模式促使机场群倾向于形成点对点航线网络结构，反之，在高补贴模式下机场群易于形成枢纽辐射航线网络； （2）在较低的空铁联运总运营成本环境下，补贴竞争使得航空公司倾向于选择系统内的大型机场作为枢纽机场；反之，如果空铁联运总运营成本相对较高，补贴竞争使得航空公司倾向于选择小机场作为枢纽节点； （3）随航班固定成本和空铁联运总运营成本的增大，大型机场作为枢纽节点的概率逐渐减少，而小机场被选为枢纽节点的概率将逐渐增大. 随着机场群内大型机场腹地服务人口比例的增大，航空公司选择点对点航线网络的概率在减小. 研究结论能够为民航管理部门科学制定和应用航线补贴政策提供决策依据.     

烃族组成对柴油储存安定性影响研究

针对柴油储存过程中质量衰变问题，利用典型柴油样品，开展烃化合物对中国成品柴油储存安定性影响规律研究。烃组成分析测定结果表明，柴油中总芳烃和链烷烃之间存在很强的相关性（相关系数为0.90）。综合采用相关分析、逐步线性回归等方法，建立了安定性指标与烃组成的关联模型，拟合验证表明模型可靠，可以直接用于柴油储存安定性预测；研究确定了柴油储存安定性的主要影响物质，按照对储存安定性指标影响的严重程度将烃类物质分为三个等级，其中苊烯和三环芳烃对柴油质量衰变影响最大，链烷烃对十六烷值和热值影响最大。     

Blockage of the NLRP3 inflammasome by MCC950 improves anti-tumor immune responses in head and neck squamous cell carcinoma

The NLRP3 inflammasome is a critical innate immune pathway responsible for producing active interleukin (IL)-1β, which is associated with tumor development and immunity. However, the mechanisms regulating the inflammatory microenvironment, tumorigenesis and tumor immunity are unclear. Herein, we show that the NLRP3 inflammasome was over-expressed in human HNSCC tissues and that the IL-1β concentration was increased in the peripheral blood of HNSCC patients. Additionally, elevated NLRP3 inflammasome levels were detected in tumor tissues of Tgfbr1/Pten 2cKO HNSCC mice, and elevated IL-1β levels were detected in the peripheral blood serum, spleen, draining lymph nodes and tumor tissues. Blocking NLRP3 inflammasome activation using MCC950 remarkably reduced IL-1β production in an HNSCC mouse model and reduced the numbers of myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) and tumor-associated macrophages (TAMs). Moreover, inhibiting NLRP3 inflammasome activation increased the numbers of CD4⁺ and CD8⁺ T cells in HNSCC mice. Notably, the numbers of exhausted PD-1⁺ and Tim3⁺ T cells were significantly reduced. A human HNSCC tissue microarray showed that NLRP3 inflammasome expression was correlated with the expression of CD8 and CD4, the Treg marker Foxp3, the MDSC markers CD11b and CD33, and the TAM markers CD68 and CD163, PD-1 and Tim3. Overall, our results demonstrate that the NLRP3 inflammasome/IL-1β pathway promotes tumorigenesis in HNSCC and inactivation of this pathway delays tumor growth, accompanied by decreased immunosuppressive cell accumulation and an increased number of effector T cells. Thus, inhibition of the tumor microenvironment through the NLRP3 inflammasome/IL-1β pathway may provide a novel approach for HNSCC therapy.     

定期保障模式下舰船编队携行备件配置优化

舰船编队海上任务期间,需要制定合理的携行备件方案以提高装备的战备完好性.针对海上定期保障模式下,将多层级复杂装备结构等效为单层级,提出一种备件需求分析与配置优化的近似方法,根据系统可靠性理论,建立了多阶段任务下的装备可用度评估模型,采用基于补给周期的分段求解方法.通过算例,采用边际优化算法得到携行备件优化方案,对模型结果进行了仿真验证,结果表明:模型计算结果与仿真结果吻合,两种取整方式下的方案费效比相当,采用定期保障模式能够提高备件供应效率,进一步增强备件方案的鲁棒性.     

基于深度学习的建筑物识别

针对随着城市化的快速发展,城市与城市间的辨识度越来越弱,城市地标的概念越来越热门这一现象,提出了一种基于深度学习的建筑物识别方法;使用改进的Faster R-CNN算法作为训练模型,首先,将需要识别的图片输入深度神经网络,提取出特征框图;然后,模型通过区域建议网络预测目标建筑物所在位置的区域建议,并将这些区域建议映射到特征框图上,RoI Pooling层将这些区域建议转换成固定大小的特征框图;最后使用非极大值抑制从预测边界框中移除相似的结果,得到预测边界框以及边框中目标建筑物的类别和概率;实验结果表明:在训练数据集充足的条件下,使用此方法对地标建筑物的识别率能达到90. 8%,通过与其他模型比较分析,该模型具有较好的识别效果。     

Exendin-4螺旋结构对生物活性及稳定性的影响

针对Exendin-4的螺旋结构特点, 采用去掉螺旋序列、 用3个连续Ala替换螺旋以及Gln13替换为Tyr13的方式对N端α-螺旋及C端α-螺旋进行改造, 设计出4个结构模拟物. 通过圆二光谱和荧光光谱进行结构分析, 结合模拟物生物活性实验, 分析Exendin-4螺旋结构与生物活性的关系. 结果表明：  Exendin-4的N端螺旋比C端螺旋对生物活性影响更大； 在抗二肽基肽酶（DPPⅣ酶）的稳定性实验中, C端螺旋比N端螺旋具有更好维系Exendin-4稳定性的作用； 螺旋结构中Tyr13可作为提高Exendin-4生物活性的重要优化位点.