带参数集值向量优化问题ε-强有效点集的连通性

主要研究了带参数ε-强有效点集的连通性。首先在局部凸的Hausdorff拓扑线性空间中引进了带参数的ε-强有效点集的概念,然后在可行域为弧连通紧、目标函数为C-弧连通的集值映射的情况下,证明了ε-强有效点集非空并得到了带参数的ε-强有效点集的连通性。

Motor Control Network Effective Connectivity in Regulating Muscle Force Output

Objective of the study: This study aimed at characterizing output features of the higher-order motor control centers (hoMCCs), including secondary (premotor cortex [Pre] and supplementary motor area [SMA]) and association (prefrontal cortex [PFC]) motor regions to the primary motor cortex (M1) during graded force tasks. It is well known that one of the major roles of the primary motor cortex (M1) is controlling motor output such as muscle force. However, it is unclear how the hoMCCs interact with M1 in regulating voluntary muscle contractions. Methods: fMRI data was acquired during graded force tasks and fMRI-based effective connectivity (EC) and muscle force analyses were performed to study the relationship between hoMCCs-M1 effective connectivity and voluntarily exerted handgrip force. Results: The results show that there is a consistent information flow from the hoMCCs to M1 under all force conditions, suggesting a hierarchical control mechanism in the brain in regulating voluntary muscle force. Only the premotor cortex exhibited a significant role in mediating the level of force production through its EC with M1 but that role diminished when the exerted force was high, suggesting perhaps a ceiling and/or fatigue effect on the EC. A flip in the direction of EC from the primary sensory cortex (S1) to the hoMCCs (PFC, SMA, and Pre) at lower force levels while at higher forces EC was observed from the hoMCCs to S1. Conclusion: The hoMCCs regulate M1 output to produce desired voluntary muscle force. Only the Pre-to-M1 connectivity strength directly correlates with the force level especially from low to moderate levels. The hoMCCs are involved in modulating higher force production likely by strengthening M1 output and downgrading inhibition from S1 to M1.

中美国债收益率溢出效应及其影响因素研究

中美国债收益率之间的溢出效应对于国际资本流动、货币政策有效性乃至金融市场稳定具有重要影响。本文采用动态Nelson-Siegel模型提取了中美两国国债收益率水平、斜率和曲率三个因子,反映利率期限结构曲线的不同特征。在此基础上,运用时变参数向量自回归关联(TVP-VAR connectedness)方法与TVP-VAR模型,分析中美国债收益率因子的溢出效应及其影响因素,发现中美国债收益率之间的溢出效应具有较强的时变性与非对称性,人民币汇率贬值与中国短期跨境资本流动增加可放大中美国债收益率的溢出效应,中国宏观经济景气程度与中美国债收益率净溢出水平反向变动。基于此,中国应继续健全和发展国债市场,完善国债交易品种与交易机制;继续深化汇率市场化改革,坚持金融市场双向开放,提高抵御短期资本流动风险的能力,保持货币政策的独立性,增强抵御国际债券市场联动冲击的能力。

子公司“自下而上”的制衡:实现路径、弱化因素与作用边界

如何有效约束大股东掏空行为是公司治理学术界与实践界共同关注的焦点问题。传统的委托代理框架遵循母子公司“自上而下”的单向治理逻辑,忽视了子公司的自主性及其“自下而上”的制衡能力,难以从根本上解决子公司及其中小股东利益保护问题。尽管单向治理范式已经受到学者的质疑,但子公司通过何种方式对母公司产生制衡亟需进一步探索。文章基于前景理论的核心观点,运用2012—2017年中国上市子公司的平衡面板数据,采用多元回归方法验证了子公司管理者异质性对大股东掏空行为的影响,阐释了子公司“自下而上”制衡作用的实现路径、弱化因素及其作用边界。研究结果表明:上市子公司拥有能力较强的管理团队能够显著抑制大股东掏空行为。一方面,能力较强的管理者可以为大股东带来更多的控制权共享收益,限制了其控制权私有收益的获取,另一方面,也能够更加有效地识别与监督大股东的掏空行为,进而起到对大股东“自下而上”的制衡作用。作为具有双重效应的情境变量,CEO声誉及CEO与母公司关联度在中国情境下的负面效应更为凸显,二者均会弱化管理者能力对大股东掏空行为的制衡作用,即在子公司CEO声誉水平较高、子公司CEO与母公司关联度较强的情境下,子公司管理者能力对大股东掏空行为的抑制作用较弱。在拓展性研究中,根据子公司股权集中度与股权制衡度进行分组,对不同股权结构下子公司管理者能力的制衡作用进行比较。结果发现,在低股权集中度与高股权制衡度的样本中,子公司管理者能力对大股东掏空行为的抑制效应显著,而在高股权集中度与低股权制衡度的样本中,即在大股东拥有较多的控制权,其他股东对大股东的制衡作用较弱的情况下,子公司管理者能力对大股东掏空行为的抑制作用难以显现,进一步揭示了子公司管理者能力的作用边界。经过工具变量法、分组回归、替换变量等稳健性检验与内生性处理之后,原结论依旧成立。研究结论补充和丰富了管理者能力在公司治理领域的研究,突破了传统“自上而下”单向治理理论的观点,验证了子公司“自下而上”制衡机制的可行性,为解决以大股东机会主义为特征的第二类代理问题提供了新的思路与经验证据。

双重视角下金融与科技的空间关联效应研究

本文构建基于邻接权重矩阵和经济权重矩阵的空间面板模型,从宏观层面和企业层面双重视角探索中国31个省份金融发展对科技创新的空间关联效应。通过研究发现:在宏观层面,金融结构和政府科技资金投入会推动本地科技创新,金融规模会推动周边地区的科技创新,但科技资金投入与金融规模的交互项能抑制周边地区的科技创新。在企业层面,金融发展和企业科技资金、人员投入会推动本地企业科技创新,但企业科技资金投入和金融效率的交互项能抑制本地和周边地区企业的科技创新。基于此,本文提出了优化科技金融资源配置、鼓励区域间科技创新合作、合理选择企业融资方式与竞争合作战略等建议。

Differential aberrant connectivity of precuneus and anterior insula may underpin the diagnosis of schizophrenia and mood disorders

BACKGROUND Over the past decade,resting-state functional magnetic resonance imaging(rsfMRI)has concentrated on brain networks such as the default mode network(DMN),the salience network(SN),and the central executive network(CEN),allowing for a better understanding of cognitive deficits observed in mental disorders,as well as other characteristic psychopathological phenomena such as thought and behavior disorganization.AIM To investigate differential patterns of effective connectivity across distributed brain networks involved in schizophrenia(SCH)and mood disorders.METHODS The sample comprised 58 patients with either paranoid syndrome in the context of SCH(n=26)or depressive syndrome(Ds)(n=32),in the context of major depressive disorder or bipolar disorder.The methods used include rs-fMRI and subsequent dynamic causal modeling to determine the direction and strength of connections to and from various nodes in the DMN,SN and CEN.RESULTS A significant excitatory connection from the dorsal anterior cingulate cortex to the anterior insula(aI)was observed in the SCH patient group,whereas inhibitory connections from the precuneus to the ventrolateral prefrontal cortex and from the aI to the precuneus were observed in the Ds group.CONCLUSION The results delineate specific patterns associated with SCH and Ds and offer a better explanation of the underlying mechanisms of these disorders,and inform differential diagnosis and precise treatment targeting.

中学生自信与未来受教育取向的关系:学校联结的中介作用

为了探讨中学生自信与未来受教育取向的关系以及学校联结的中介作用,采用未来取向问卷、学校联结问卷和青年学生自信问卷对412名中学生进行了测查。结果显示,总体自信与学校联结,总体自信与未来受教育取向,学校联结与未来受教育取向均存在正相关;学校联结在总体自信与未来受教育取向之间存在显著的部分中介效应;学校联结在成就自信与未来受教育取向,品质自信与未来受教育取向之间也存在显著的部分中介效应。中学生的学校联结既是总体自信与未来受教育取向之间的中介变量,也是成就自信与未来受教育取向之间、品质自信与未来受教育取向之间的中介变量。

特质敬畏对大学生自然联结的影响:自然美感的中介作用

采用特质敬畏量表、自然联结量表、自然美感量表对566名大学生进行测量,考察特质敬畏与自然联结的关系,以及自然美感在特质敬畏与自然联结关系中的中介作用。结果显示:(1)特质敬畏显著正向预测自然联结;(2)特质敬畏可以通过自然美感显著正向预测大学生自然联结。结论:特质敬畏可以通过自然美感的部分中介作用对大学生自然联结产生影响。

关于多因子方差模型的互补约束和互补连通性

对于多因子不完全实验和模型,笔者提出了效应互补约束和模型互补连通问题;证明了具有互补约束和两个方差模型,其最小无偏设计的网子点子集也具有互补性.这一互补连通原理将文[1]关于谱系效应模型连通性和定理扩展为关于谱系余效应模型的相应结果.

全球股票市场系统性金融风险的溢出效应研究——基于关联网络的研究视角

在开放的全球经济体系下,各国或地区金融市场的关联性不断上升,局部金融风险通过关联网络不断地扩散,进而形成全球性的金融危机,系统性风险溢出的网络特征受到各界的广泛关注。根据2005—2019年全球主要股票市场的股指数据,采用网络拓扑方法测度全球股市风险溢出效应,并采用滚窗估计对系统性风险溢出进行动态分析。实证结果表明,美国处于全球风险溢出网络的中心地位,而中国尚处于网络边缘,并与周边经济体产生明显的溢出效应。此外,全球系统性金融风险溢出水平呈现出一种“脆弱”的状态,易受风险事件的冲击。

Establishment of Long-term Mechanism for Preventing Poverty Return through Education in Rural Revitalization in Southern Shaanxi

General Secretary of CPC Central Committee Xi Jinping has stated that education must be emphasized in order to fundamentally eliminate poverty and achieve effective linkage with rural revitalization.According to the Outline of China's Rural Poverty Alleviation and Development(2011-2020),Shaanxi Province has 29 poverty-stricken counties,of which 27 are in southern Shaanxi and 11 are deeply poverty-stricken counties,accounting for nearly 40%of the contiguous poverty-stricken areas in Qinling-Daba mountains.Therefore,the key to poverty alleviation and rural revitalization in Shaanxi lies in southern Shaanxi.Although the current poverty alleviation in southern Shaanxi has achieved remarkable results,there are still high risks and hidden dangers of poverty return.Therefore,taking southern Shaanxi as the field survey point,based on the problem orientation and the main line,this paper deeply explored the common risks and causes of establishing education anti-poverty mechanism to connect with the rural revitalization strategy,and effectively put forward the feasible ideas and countermeasures for establishing long-term mechanism for preventing poverty return through education.

The right inferior frontal gyrus as pivotal node and effective regulator of the basal ganglia-thalamocortical response inhibition circuit

Background:The involvement of specific basal ganglia-thalamocortical circuits in response inhibition has been extensively mapped in animal models.However,the pivotal nodes and directed causal regulation within this inhibitory circuit in humans remains con-troversial.Objective:The main aim of the present study was to determine the causal information flow and critical nodes in the basal ganglia-thalamocortical inhibitory circuits and also to examine whether these are modulated by biological factors(i.e.sex)and behavioral performance.Methods:Here,we capitalize on the recent progress in robust and biologically plausible directed causal modeling(DCM-PEB)and a large response inhibition dataset(n=250)acquired with concomitant functional magnetic resonance imaging to determine key nodes,their causal regulation and modulation via biological variables(sex)and inhibitory performance in the inhibitory circuit encompassing the right inferior frontal gyrus(rIFG),caudate nucleus(rCau),globus pallidum(rGP),and thalamus(rThal).Results:The entire neural circuit exhibited high intrinsic connectivity and response inhibition critically increased causal projections from the rIFG to both rCau and rThal.Direct comparison further demonstrated that response inhibition induced an increasing rIFG inflow and increased the causal regulation of this region over the rCau and rThal.In addition,sex and performance influenced the functional architecture of the regulatory circuits such that women displayed increased rThal self-inhibition and decreased rThal to GP modulation,while better inhibitory performance was associated with stronger rThal to rIFG communication.Furthermore,control analyses did not reveal a similar key communication in a left lateralized model.Conclusions:Together,these findings indicate a pivotal role of the rIFG as input and causal regulator of subcortical response inhibition nodes.

Age-related connectivity differences between attention deficit and hyperactivity disorder patients and typically developing subjects：a resting-state functional MRI study

Attention deficit and hyperactivity disorder（ADHD） is a disorder characterized by behavioral symptoms including hyperactivity/impulsivity among children,adolescents,and adults.These ADHD related symptoms are influenced by the complex interaction of brain networks which were under explored.We explored age-related brain network differences between ADHD patients and typically developing（TD） subjects using resting state f MRI（rs-f MRI） for three age groups of children,adolescents,and adults.We collected rs-f MRI data from 184 individuals（27 ADHD children and 31 TD children;32 ADHD adolescents and 32 TD adolescents;and 31 ADHD adults and 31 TD adults）.The Brainnetome Atlas was used to define nodes in the network analysis.We compared three age groups of ADHD and TD subjects to identify the distinct regions that could explain age-related brain network differences based on degree centrality,a well-known measure of nodal centrality.The left middle temporal gyrus showed significant interaction effects between disease status（i.e.,ADHD or TD） and age（i.e.,child,adolescent,or adult）（P 0.001）.Additional regions were identified at a relaxed threshold（P 0.05）.Many of the identified regions（the left inferior frontal gyrus,the left middle temporal gyrus,and the left insular gyrus） were related to cognitive function.The results of our study suggest that aberrant development in cognitive brain regions might be associated with age-related brain network changes in ADHD patients.These findings contribute to better understand how brain function influences the symptoms of ADHD.

Abnormal Effective Connectivity in the Brain is Involved in Auditory Verbal Hallucinations in Schizophrenia

Information flow among auditory and language processing-related regions implicated in the pathophysiology of auditory verbal hallucinations（AVHs） in schizophrenia（SZ） remains unclear. In this study, we used stochastic dynamic causal modeling（s DCM） to quantify connections among the left dorsolateral prefrontal cortex（inner speech monitoring）, auditory cortex（auditory processing）, hippocampus（memory retrieval）, thalamus（information filtering）, and Broca＇s area（language production） in 17 first-episode drug-na？¨ve SZ patients with AVHs, 15 without AVHs, and 19 healthy controls using resting-state functional magnetic resonance imaging.Finally, we performed receiver operating characteristic（ROC） analysis and correlation analysis between image measures and symptoms. s DCM revealed an increasedsensitivity of auditory cortex to its thalamic afferents and a decrease in hippocampal sensitivity to auditory inputs in SZ patients with AVHs. The area under the ROC curve showed the diagnostic value of these two connections to distinguish SZ patients with AVHs from those without AVHs. Furthermore, we found a positive correlation between the strength of the connectivity from Broca＇s area to the auditory cortex and the severity of AVHs. These findings demonstrate, for the first time, augmented AVHspecific excitatory afferents from the thalamus to the auditory cortex in SZ patients, resulting in auditory perception without external auditory stimuli. Our results provide insights into the neural mechanisms underlying AVHs in SZ. This thalamic-auditory cortical-hippocampal dysconnectivity may also serve as a diagnostic biomarker of AVHs in SZ and a therapeutic target based on direct in vivo evidence.

我国金融机构的系统性风险溢出研究:测度、渠道与防范对策

本文采用基于QFVAR模型的广义方差分解方法测度我国上市金融机构在极端负面与正面冲击下的尾部风险溢出,并分析金融体系和各家机构的风险溢出水平。在此基础上,本文使用面板回归模型检验了机构间风险溢出的主要渠道以及两类宏观审慎政策工具的有效性。研究发现:第一,在样本期间,金融体系面对不同方向冲击所产生的风险溢出水平具有截然不同的趋势特征,左尾溢出(负面冲击)和右尾溢出(正面冲击)分别由金融市场波动与行业杠杆水平所驱动。第二,受到负面冲击后,规模较大的金融机构具有较高的风险溢出水平,而杠杆水平较高的机构则是正面冲击下的高风险溢出机构。第三,金融机构在负面冲击下通过直接关联与间接关联渠道向外溢出风险,而正面冲击引发的风险溢出则主要通过信息关联渠道得以实现。第四,流动类政策工具可以显著减弱金融机构在直接关联渠道下的风险溢出水平,而资本类政策工具则可以显著减弱机构在间接关联与信息关联渠道下的风险溢出水平。

城市房价波动关联性、溢出效应及影响因素分析

本文基于大型时变参数向量自回归(TVP-VAR)模型测度了全国35个大中城市房价波动的整体时变关联性,以及城市间的时变波动溢出效应。研究表明,房价波动关联性指数呈周期性震荡态势,易受外部冲击急剧攀升;不同城市的波动溢出效应呈显著结构性差异,二线城市的波动溢出作用在房价下行期间表现更为强烈。具体来看,东部二线城市是波动溢出作用的主要输出方,而中西部城市则是波动溢出的主要接受者。进一步地,本文基于部分宏观经济指标及区域性数据探讨房价波动关联的背后成因,发现货币供给量、宏观经济状况及经济政策不确定与房价波动的整体关联性显著相关,而跨地区的波动溢出效应则可以较好地由经济基本面及市场传染机制加以解释。

国际股市间动态相依性及高阶矩风险溢出效应研究

基于DECO-FIAPARCH和cADCC-FIAPARCH模型从全局视角及两两股市层面刻画国际股市间的相依结构,并首次将GARCHSK高阶矩波动模型与Connectedness方法相结合,量化国际股市间的高阶矩风险溢出效应.实证结果表明:国际股市间的动态等相关性具备显著的时变性,且易受到重大危机事件的冲击而增强.总体而言,欧美股市间的相关性高于亚洲股市,中国大陆与中国香港、日本、印度以及东南亚股市的相关性较高,而与欧美(美国、加拿大、法国、德国、阿根廷、希腊)股市的相关性较低.国际股市间的高阶矩风险溢出效应较为显著,且美国、墨西哥、加拿大和英国(日本、菲律宾、泰国、土耳其、中国香港)股市是最主要的高阶矩风险净溢出者(净接受者),重大国际危机事件会强化高阶矩风险溢出效应,中国香港股市既是中国大陆的风险传染源之一,同时也是大陆股市与国际股市间风险溢出的重要传播媒介.构建包含中国大陆股市与其余股市的投资组合可以显著降低原始投资组合的风险,最优权重投资组合较等权重投资组合具备更高的风险管理有效性.

A review of functional magnetic resonance imaging for Brainnetome

The functional brain network using blood-oxygen-level-dependent（BOLD） functional magnetic resonance imaging（fMRI） has revealed the potentials for probing brain architecture,as well as for identifying clinical biomarkers for brain diseases.In the general context of Brainnetome,this review focuses on the development of approaches for modeling and analyzing functional brain networks with BOLD fMRI.The prospects for these approaches are also discussed.

Separate Neural Networks for Gains and Losses in Intertemporal Choice

An important and unresolved question is how human brain regions process information and interact with each other in intertemporal choice related to gains and losses. Using psychophysiological interaction and dynamic causal modeling analyses, we investigated the functional interactions between regions involved in the decision- making process while participants performed temporal discounting tasks in both the gains and losses domains. We found two distinct intrinsic valuation systems underlying temporal discounting in the gains and losses domains： gains were specifically evaluated in the medial regions, including the medial prefrontal and orbitofrontal cortices, and losses were evaluated in the lateral dorsolateral prefrontal cortex. In addition, immediate reward or pun- ishment was found to modulate the functional interactions between the dorsolateral prefrontal cortex and distinct regions in both the gains and losses domains： in the gains domain, the mesolimbic regions; in the losses domain, the medial prefrontal cortex, anterior cingulate cortex, and insula. These findings suggest that intertemporal choice of gains and losses might involve distinct valuation systems, and more importantly, separate neural interactions may implement the intertemporal choices of gains and losses. These findings may provide a new biological perspective for understanding the neural mechanisms underlying intertemporal choice of gains and losses.

自然联结对大学生抑郁的影响:有调节的中介模型

为考察自然联结与大学生抑郁的关系,采用问卷法对中部地区6所高校四个年级共720名大学生进行调查。结果显示:(1)自然联结显著负向预测大学生抑郁;(2)生命意义感在自然联结与抑郁的关系中起部分中介作用;(3)自然联结对大学生抑郁的直接效应和生命意义感的中介效应均受到了感恩的调节,且这两种效应均在感恩水平较高时更为显著。在前半路径中,感恩增强了自然联结对生命意义感的影响;在直接路径中,自然联结对抑郁的影响在感恩水平较高时更强。研究结果对于预防大学生抑郁具有重要参考价值。