泰乐松注射液的毒理学试验研究

为提供泰乐松注射液的安全性毒理学评价资料,本试验采用改进Karber法测定小鼠LD_(50);以剂量递增法测定小鼠蓄积性和耐受性;分别以剂量340、130、30mg／kg为3个试验组．设阴性和阳性对照组进行小鼠骨髓微核试验;分别以剂量500、250、120mg／kg为3个剂量组．设阴性和阳性对照组进行小鼠精于畸形试验。结果表明：其LD_(50)为669．80mg／kg,蓄积系数大于5．3,无明显蓄积毒性和耐受性（P＞0．05）,小鼠骨髓微核试验和精子畸形试验结果均为阴性。     

中国二板市场应无限期推迟——从海外二板市场的教训看中国开设二板的艰难性

德国、日本、澳大利亚及香港等海外二板市场失败的原因是由于其大幅度降低了公司入市的标准和要求,有其必然性。美国纳斯达克市场尚存的原因是其特性与主板有重叠之处,从超长期看,其是否成功还难以确定。本文指出中国拟创立的二板市场理由、目标与海外二板市场衰败的原因如出一辙;加之中国A股市场股本结构分裂,股价高企,没有做空机制,二板市场贸然推出,不仅本身可能会蹈海外多数二板市场的覆辙,而且可能对主板A股市场形成严重影响,故建议中国二板市场无限期推迟。在主板市场可通过附设一个科技创业分板,并应尽快恢复深圳证券市场新股发行工作。     

Stable and visualizable Gaussian parsimonious clustering models

Gaussian mixture model-based clustering is now a standard tool to determine a hypothetical underlying structure in continuous data. However, many usual parsimonious models, despite either their appealing geometrical interpretation or their ability to deal with high dimensional data, suffer from major drawbacks due to scale dependence or unsustainability of the constraints after projection. In this work we present a new family of parsimonious Gaussian models based on a variance-correlation decomposition of the covariance matrices. These new models are stable when projected into the canonical planes and, so, faithfully representable in low dimension. They are also stable by modification of the measurement units of the data and such a modification does not change the model selection based on likelihood criteria. We highlight all these stability properties by a specific graphical representation of each model. A detailed Generalized EM (GEM) algorithm is also provided for every model inference. Then, on biological and geological data, we compare our stable models to standard ones (geometrical models and factor analyzer models), which underlines all the profit to obtain unit-free models.     

乡村教师科研培训课程体系的构建——基于粤西北的调查

调查显示，乡村教师的科研处于初始或停滞状态，亟需构建科研能力培训课程体系。乡村教师缺乏教育教学反思能力是现实中普遍存在的问题，为此要加强对乡村教师教育理论知识的重温与重构。另外，针对乡村教师科研热情不高的现状，要建立科研培训课程体系。一方面，根据教育实践问题为科研活动提供研究方向，设置侧重科研过程原则性和步骤性的培训课程；另一方面，将乡村教师在日常教育教学中生发的心得体会和经验总结转化为科研论文，设置科研论文写作的培训课程。     

城市高密度人口分布下的社区建设——以广州荔湾区为例

以广州荔湾区“六普”资料为根据，就人口高密度分布与社区建设的关系进行梳理与探讨。荔湾区“六普”数据显示，城区人口密度过高，成为影响社区生活的主要因素，给居民生命安全、公共生活质量与日常生活便利性带来负面效应。科学化与人性化人口密度干预是治理高密度人口问题的理性策略，如“跳出”社区视野，在城市“一盘棋”中均衡人口布局，在社区建设中，通过社区更新改造，增强人口承载能力，通过建构便利舒适人居环境，提升社区生活质量。     

小微民营企业政治参与研究——以我国中部地区为例

改革开放以来,小微民营企业对我国经济发展做出了重要贡献。不仅如此,它们在技术创新、吸纳就业乃至社会稳定等领域的贡献也是有目共睹。然而,在我国的政治舞台上,却始终看不到小微民营企业的身影。它们一方面希望能够维持企业的生存,另一方面却不得不面对诸多的政策障碍。在遇到上述问题时,由于缺乏参政议政和投诉的渠道,多数小微民营企业只能选择沉默或忍气吞声。而且,长期以来与决策者沟通的缺乏导致它们对政治参与缺乏热情,对决策过程缺乏了解,对政府扶持心存疑虑。针对这些问题,要求政府在行政方面做出改进的同时,小微民营企业也应该改进自己的行为。     

Split Hamiltonian Monte Carlo

We show how the Hamiltonian Monte Carlo algorithm can sometimes be speeded up by “splitting” the Hamiltonian in a way that allows much of the movement around the state space to be done at low computational cost. One context where this is possible is when the log density of the distribution of interest (the potential energy function) can be written as the log of a Gaussian density, which is a quadratic function, plus a slowly-varying function. Hamiltonian dynamics for quadratic energy functions can be analytically solved. With the splitting technique, only the slowly-varying part of the energy needs to be handled numerically, and this can be done with a larger stepsize (and hence fewer steps) than would be necessary with a direct simulation of the dynamics. Another context where splitting helps is when the most important terms of the potential energy function and its gradient can be evaluated quickly, with only a slowly-varying part requiring costly computations. With splitting, the quick portion can be handled with a small stepsize, while the costly portion uses a larger stepsize. We show that both of these splitting approaches can reduce the computational cost of sampling from the posterior distribution for a logistic regression model, using either a Gaussian approximation centered on the posterior mode, or a Hamiltonian split into a term that depends on only a small number of critical cases, and another term that involves the larger number of cases whose influence on the posterior distribution is small.     

人工智能时代的话语悖论与结构转向

以追求智能、精准为核心的技术认知对突发社会问题的预测失灵,形塑了人工智能时代的话语悖论。此悖论体现出盲目崇尚加速的、闭合化的现代性认知结构的困窘,且揭示了晚近技术反思的谱系化与经验"二分"的双重结构观的局限性,进而使超越悖论的结构转向成为必须面对的命题。因此关键在于以突发社会问题为节点,面向日常生活,实现对"二分"的总体性统合。唯有把握日常生活在突发问题中可能产生的反转契机,合理审视智能化的技术,促使技术的精准思维融入于日常生活之中,方能为加速多变的现代科学创设总体化的良善格局。     

Fibonacci helps to evacuate from a convex region in a grid network

This study considers an evacuation problem where the evacuees try to escape to the boundary of an affected area, which is convex, and a grid network is embedded in the area. The boundary is unknown to the evacuees and we propose an online evacuation strategy based on the Fibonacci sequence. This strategy is proved to have a competitive ratio of 19.5, which is better than the best previously reported result of 21.     

Factors that Determine or Influence Managerial Innovation in Public Contexts: The Case of Local Performance Management

The use of Performance-Based Management (PBM) by French public organizations has sharply accelerated over the last few years. Moreover, very few studies have analyzed this change. The object of this article is thus to conduct an in-depth analysis of the dynamics of managerial innovation in three French local authorities via the study of the factors that foster the adoption and implementation of PBM by this type of organization. We demonstrate a tendency to overestimate the explanatory power of the neo-institutionalist theories. Indeed, our analysis illustrates a balanced vision of the human, technical and contextual factors at the origin of this type of managerial innovation.