基于角膜图像的人体死亡时间推断模型初探

目的尸体角膜随死后时间延长发生的形态学变化是规律性较好的指标,常用来判断死亡时间(postmortem interval,PMI)。本文尝试用机器视觉代替人的肉眼主观判断,收集尸体样本以建立通过人体角膜图像推断PMI的模型。方法收集实际案例建立包含505例人体死后角膜图像的数据库,PMI范围为0.24h(约死后14min)至492h(约死后20.5d),大致分为三类(依次为:0~<6h、6~<20h、20h及以上)或二类(0~<15h、15h及以上);使用由华盛顿大学陈天奇博士提出的Xgboost模型分别进行二分类与三分类分析;使用多种卷积神经网络模型分别进行分类和回归学习,并通过比较最终选择了由微软研究院提出的ResNet模型进行分析。结果Xgboost在三分类时预测准确率依次为71.8%、40.7%、65.7%,二分类时为90%、48.5%。ResNet分类模型中,精准率、召回率在三分类时分别依次为:81%、75%,30%、50%,61%、71%,二分类时为:70%、92%,76%、38%。ResNet回归模型中,比较整个模型的预测结果,0~6h内的预测值与真实值较为接近,均值误差为0.5616,均方误差为0.5873,6h之后开始出现较大误差。结论分类和回归模型都在0~6h之内得到了很好的结果,说明在此时间段内,角膜图像噪声较低,可预测性强。     

Introduction to Performing Refusal/Refusing to Perform

This introduction outlines an aesthetic of refusal as it emerges from instances of racialized exhaustion. Described as an aesthetics of minoritarian inaction and non-reproductivity, refusal challenges the centrality of action and repetition as the central tenets of political performance. Instead, the two valences of performing refusal/refusing to perform name an ethics of relation under racial capitalism, negating the dialectic of assimilation or resistance that shape minoritarian political performance, in favor of tactics such as opacity, imperceptibility, and obscurity.     

利用尸体角膜内皮细胞活性率判定死后经过时间的研究

本研究对已知死亡时间的500只非正常死亡者的角膜内皮细胞进行染色观察，以单位面积内的活性内皮细胞与细胞总数之比作为活性率，发现角膜内皮细胞活性率（Endothelialcelllivinsrate，ECLR）随死后经过时间（postmorteminterval，PMI）的延长而逐渐降低，数理分析表明两者之间的关系为负相关，因此，认为检测尸体角膜内皮细胞活性的方法可为法医学推断死后经过时间提供一新的组织学手段。     

家兔死后不同时间角膜基质胶原纤维的超微结构观察

目的探讨角膜基质胶原纤维直径变化与死亡时间的关系。方法28只家兔空气栓塞致死后,按死后不同时间取角膜,常规方法制作超薄切片,应用透射电镜观察角膜基质0.5μm×0.5μm区域内的胶原纤维,并用图像分析系统测量反映胶原纤维直径变化的横切面面积(Y1)、周长(Y2)、平均直径(Y3)、等效直径(Y4)4个参数,所得数据用EXCEL2000和SPSS10.0软件进行统计分析。结果在死后0～72h内,角膜胶原纤维横断面的面积从1131±53nm增加到1628±26nm,周长从132.8±23nm增加到167.5nm,等效直径从38nm增加到45nm,平均直径从37.71±6nm增加到44.89±5nm。结论死后72h内,角膜基质胶原纤维直径随死后时间的延长逐渐增大,4个参数有望作为判断死后时间的新指标。     

Political Risk: The Institutional Dimension

The argument developed in this paper is that the political arrangements and institutions that help leaders stay in office are not necessarily the ones that promote economic growth and prosperity. Indeed political leaders can remain in office more securely by rewarding the groups that keep them in power with privileged access to public resources. The net result is that the leadership remains in office but at the price of poor economic performance. It is not that the consequences of mismanaging the economy are unforeseen; rather the increased chances of an economic crisis are an acceptable price to pay if it means avoiding a political crisis which challenges the leaders' hold on power. Political survival, not peace and prosperity, is what determines the choice of policies. In this way bad economics can be good politics. The principal hypothesis addressed is that the smaller the size of the winning coalition the more the leadership depends on distributing private goods to the coalition members in order to purchase their loyalty, and, therefore the greater is the level of political risk. The ultimate effects of coalition size and the corruption attending the competition for private goods are the reduction of foreign direct investment per capita. These hypotheses were tested in a three stage least squares (3SLS) simultaneous estimation. The results generally supported the theoretical expectations.     

The observer actant in the contemporary legal discourse: a semiotic meditation*

ABSTRACT

The sensorial access to the law that a society grants to its members is underpinned by a logic of exhibition and disclosure that, in turn, results from a more abstract cultural propensity to either transparency or opacity. Through investigating the systems of signs by which the functioning of the law is either concealed to external audiences or manifested to them in a more or less spectacular way, one can gain a firmer grasp on the juridical aesthetics of a society. This semiotic approach entails two advantages: on the one hand, the possibility to compare and contrast different regimes of disclosure and secrecy in the synchronic dimension, connecting the discourse of the law with other – apparently distant – types of discourse, adopting the same aesthetics of transparency or opaqueness in other domains of social life and discursive production; on the other hand, the opportunity for a more insightful intelligence of the diachronic development of such aesthetics, so that it may be interpreted as the long-term byproduct of historical watersheds in the history of culture. The article, in particular, proposes to link the socio-pathology of anorexia with several other practices and texts of present-day culture that adopt the same rhetoric of transparency in other discursive arena, including that of law. In all these sign productions, indeed, the trend that predominates is one that, adhering to an ideology of immediacy and transparency, pretends to eliminate all filters, all hindrances, but also all material signifiers that would mar the purity of the content. Although this utopia cannot correspond to any actual semiotic state – for any content needs a material expression to be conveyed – it nevertheless exerts a powerful influence on the present time, until it manifests itself in extreme forms of ‘transparentist’ radicalism.     

Introduction to queer circuits: Critical performance and digital praxis

This introduction situates the articles making up this special issue within four thematic clouds, positing queer theorization as broadly relevant for critically engaging with computational technologies and culture. These sub-themes offer suggestions for future queer inquiry and praxis and reflect key terms in performance studies and queer theory that have undergone transformation with the ubiquity of digital technology.     

角膜混浊的形成机制及法医学应用进展

角膜混浊是一种重要的死后变化。本文通过对角膜基质胶原纤维特殊结构,蛋白多糖水合作用及离子强度变化在角膜混浊发生中的作用及机理进行综述,并对其法医学应用进行初步探讨。     

Issue opacity and sustainability standard effectiveness

Many voluntary sustainability standards govern opaque environmental and social issues, which are difficult to understand and address. Extant studies show mixed evidence around the effectiveness of such standards. We develop a theoretical framework that relates different degrees and types of opacity to standard effectiveness. Systemic opacity results from issues embedded in complex, diverse, and dynamic settings, whereas behavioral opacity stems from human challenges in interpreting and acting upon focal issues. Rigid sustainability standards, oriented toward compliance, are effective for addressing issues that are transparent or enshrouded by behavioral opacity, but are counterproductive for issues with systemic opacity. The trade-off between rigidity and flexibility leads to optimal effectiveness when standards governing systemically and behaviorally opaque issues are moderately rigid. Our ideas are illustrated with two leading sustainability standards in the fisheries and real estate sectors, which effectively address transparent issues but show limited success when facing opacity. We conclude that unpacking issue opacity is instrumental in designing and implementing more effective sustainability standards.