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41.
This qualitative case-study explores questions about the stratifying role of public alternative schools created for ‘at-risk’ youth by analyzing the school experience of students who attend a single continuation high school and the process of student enrollment and referral to that school. Drawing on the concept of whiteness as property, this article demonstrates how the continuation high school maintained and protected the property functions of whiteness through acts of symbolic violence and the systematic removal of non-white students from the school district’s mainstream high school. Instead, students were placed in a substandard alternative school lacking in material and intellectual resources. Furthermore, teachers, counselors, and administrative staff at the mainstream and continuation high schools alike drew upon the racial ideology of merit to rationalize the overrepresentation of non-white youths at the study school and to ‘deracialize’ the student referral process.  相似文献   
42.
相对一般的技术创新,高新技术创新有其独有的一些特点,这些特点决定了文化对高新技术创新具有重要作用。高新技术创新的文化路径包括观念文化路径、制度文化路径和行动文化路径三个方面。基于文化视角优化高新技术创新的政策选择,完善我国科技政策,有助于推动高新技术的进一步创新。  相似文献   
43.
高速铁路具有高度集成、高精度的技术特点,运营过程中经受列车质量、速度、密度等多种因素影响,地理位置因素往往是影响铁路设备状态演变的决定性因素。采用网格化管理技术可将空间上连续分布的管理对象划分成较小的单元网格,有利于从空间位置角度研究管理对象状态的变化规律。随着信息系统技术、大数据技术的迅猛发展,基于位置而不是基于专业更符合高速铁路的管理需求,网格化管理技术给高速铁路管理带来了新的视角。  相似文献   
44.
Multivariate control charts are used to monitor stochastic processes for changes and unusual observations. Hotelling's T2 statistic is calculated for each new observation and an out‐of‐control signal is issued if it goes beyond the control limits. However, this classical approach becomes unreliable as the number of variables p approaches the number of observations n, and impossible when p exceeds n. In this paper, we devise an improvement to the monitoring procedure in high‐dimensional settings. We regularise the covariance matrix to estimate the baseline parameter and incorporate a leave‐one‐out re‐sampling approach to estimate the empirical distribution of future observations. An extensive simulation study demonstrates that the new method outperforms the classical Hotelling T2 approach in power, and maintains appropriate false positive rates. We demonstrate the utility of the method using a set of quality control samples collected to monitor a gas chromatography–mass spectrometry apparatus over a period of 67 days.  相似文献   
45.
The three classic pillars of risk analysis are risk assessment (how big is the risk and how sure can we be?), risk management (what shall we do about it?), and risk communication (what shall we say about it, to whom, when, and how?). We propose two complements as important parts of these three bases: risk attribution (who or what addressable conditions actually caused an accident or loss?) and learning from experience about risk reduction (what works, and how well?). Failures in complex systems usually evoke blame, often with insufficient attention to root causes of failure, including some aspects of the situation, design decisions, or social norms and culture. Focusing on blame, however, can inhibit effective learning, instead eliciting excuses to deflect attention and perceived culpability. Productive understanding of what went wrong, and how to do better, thus requires moving past recrimination and excuses. This article identifies common blame‐shifting “lame excuses” for poor risk management. These generally contribute little to effective improvements and may leave real risks and preventable causes unaddressed. We propose principles from risk and decision sciences and organizational design to improve results. These start with organizational leadership. More specifically, they include: deliberate testing and learning—especially from near‐misses and accident precursors; careful causal analysis of accidents; risk quantification; candid expression of uncertainties about costs and benefits of risk‐reduction options; optimization of tradeoffs between gathering additional information and immediate action; promotion of safety culture; and mindful allocation of people, responsibilities, and resources to reduce risks. We propose that these principles provide sound foundations for improving successful risk management.  相似文献   
46.
水平井分段多簇压裂在现场得到了广泛运用,其压裂过程中普遍存在缝间干扰现象。缝间干扰有助于形成复 杂裂缝网络以提高储层导流能力,但是也会导致起裂困难,甚至形成砂堵。因此有必要对分段多簇压裂的缝间干扰问 题进行研究。对此,基于弹性力学建立了分析多簇裂缝诱导应力的数学模型,从起裂压力、裂缝宽度、簇间距等多方面 研究了缝间干扰对水平井分段多簇压裂施工的影响。模拟结果显示,诱导应力会导致起裂压力升高、裂缝变窄,严重 时将造成压裂施工失败。通过进行分析,给出了起裂过程及延伸过程中缝间干扰的影响关系。分析认为,利用缝间干 扰提高改造体积时应当控制簇间距防止对压裂施工造成负面影响。研究结论对优化水平井分段多簇压裂设计具有指 导意义。  相似文献   
47.
We present an analysis of the contexts within which adolescents graduate from high school and enroll in college. Data from the National Longitudinal Study of Adolescent Health show that adolescents’ school engagement, maternal academic monitoring, and community poverty significantly interact to explain differences in high school graduation and college enrollment rates (n?=?7100). To examine this association, we performed weighted logistic regression analyses, controlling for gender, race, block level unemployment, and block level median income. Findings suggest that protective factors can help youth overcome the challenges associated with community poverty and achieve academically in low and medium levels of poverty, but that youth in high-poverty contexts may need more resources to reach higher levels of academic attainment.  相似文献   
48.
当今人才作为第一资源是各国家与地区之间争夺的对象,如何引进、使用和留住人才对国家和地区的经济发展具有重要意义。深圳市是全国改革开放的先锋军,在海外高层次人才引进方面走在全国前列。对深圳市海外高层次人才引进特色和优势分析,可为三亚市海外高层次人才的引进提供借鉴和启示意义,以促进三亚市发挥自身优势,吸引优势人才资源,为建设海南省国际旅游岛做出一份贡献。  相似文献   
49.
Research finds lower levels of academic performance among sexual minority high school students, but some studies suggest sexual minorities have higher levels of educational attainment in adulthood. To further our understanding of how and why sexual orientation is associated with educational success, this study turns attention to the pathways to college completion, examining points along educational trajectories in which sexual minorities fall behind or surpass their heterosexual peers. Using data from the National Longitudinal Study of Adolescent to Adult Health, we find that sexual minority women are less likely than women with no same-sex sexuality to complete college, in part due to their high school performance and transition into college. Men who experience same-sex sexuality only in adolescence struggle in high school, but men who experience same-sex sexuality for the first time in adulthood are more likely to earn a college degree than men who do not experience same-sex sexuality.  相似文献   
50.
在科学证据研究中,存在"正相关"和"高概率"两种科学证据的概率定义。从这两个定义出发,能够比较清晰直观地解释科学证据的许多相关问题,如科学证据中的"比较级"和"可接受性"等。然而,两个定义自身存在着不可忽视的缺陷:"正相关"不是证据的充要条件,"高概率"也不足以使证据之为证据。  相似文献   
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