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1.
随着人类文明的进步、社会的发展以及信息技术的普及,教育时间和空间得到迅速拓展。教育时空拓展正如一把双刃剑,给教育活动的实施带来机遇的同时也带来了挑战。教师作为教育活动的主要组织者和实施者,在享受机遇的同时也要迎接教育时空拓展所带来的挑战。通过分析教育时空拓展的内涵与表征,发现教师专业成长正处在社会化、终身化与数字化的发展大潮中,因此教师要充分利用好教育时空拓展带来的机遇,同时慎重应对由此面临的挑战,不断提高应变能力,以促进教师专业成长和教育事业的发展。  相似文献   
2.
文章基于2000—2016年重庆37个县(区)面板数据,使用序列DEA方法测算了重庆农业全要素生产率变动,在此基础上探讨了重庆农业全要素生产率增长的时间演变,并从理论和实证层面系统考察了城镇化和工业化对农业全要素生产率增长的影响。结果表明:首先,2000—2016年间重庆市农业全要素生产率呈上升趋势,2007年后重庆市农业全要素生产率增长更为明显,并且重庆市各地区呈现出明显的空间不平衡性。其次,动态面板模型的实证结果表明城镇化对农业全要素生产率增长具有显著正向影响,工业化对农业全要素生产率增长也具有显著正向影响。最后,研究还发现基础设施、教育水平以及金融发展程度对农业全要素生产率增长均具有显著正向影响,而产业结构对农业全要素生产率增长具有显著负向影响。  相似文献   
3.
This study explores the identity work carried out by three female owner‐managers in creative industry businesses, identified in Government reports as a discriminatory industrial sector for women in the UK. Through the development of narratives by the owners and other participants, observation of practice and review of online and offline materials, three cases emerged. These showed overlapping, different identities developed and performed through identity work. Each presented rational and logical persona as business leaders despite observation showing extensive use of intuition and gut feeling in both creative and entrepreneurial aspects of the business. Intuition and gut feeling were seen as inappropriate at work as they belonged to the home sphere, emotionally based and therefore automatically unreliable. While occupying male stereotypes and avoiding the female realm of emotion at work, these women expressed femininity through their emphasis on the maternal, ‘being a good mother' as a desired ideal being embedded in work as well as home practice.  相似文献   
4.
Objective: To compare anthropometric measures of body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and sagittal abdominal diameter (SAD) as predictors of blood pressure in college students. Participants: Students (N = 116) were recruited from November 2012 to May 2014 at an urban university and rural community colleges. Methods: Students underwent a brief physical examination during which anthropometric measures were obtained and blood pressure was measured. Covariates were measured using self-reported questionnaires. Hierarchical multiple linear regressions were used for the data analysis. Results: All anthropometric measures were predictive of systolic (SBP) and diastolic blood pressure (DBP). WC was the strongest predictor of SBP (β = .582, p < .01) explaining an additional 3–4% of the variance than BMI, WHtR, or SAD. The measures were similar in predicting DBP. WC predicted SBP independent of BMI. Conclusions: Clinicians should consider using WC to assess the risk for hypertension in college students.  相似文献   
5.
Availability analysis is an important issue in many practical fields. This paper investigates the availability for general repairable systems with repair time threshold. Based on practical applications, a repair time threshold is introduced. If the period of a repair is less than a predefined time threshold, then the system may be considered as working during this period, i.e., the effect of the repair could be neglected. Otherwise, if the period of a repair is longer than the given threshold, then the system is considered as working from the beginning of the system failure until the repair time exceeding the threshold, i.e., the time point of the system down could be delayed. We consider both constant and random repair time threshold. This paper valuates the user-perceived availability, when the user does not experience any service interruption because the duration of repair is too short. The results can be applied in reliability engineering, queueing theory and many other fields. A numerical example for ventilator system is presented to demonstrate the application of the developed approach.  相似文献   
6.
We propose a thresholding generalized method of moments (GMM) estimator for misspecified time series moment condition models. This estimator has the following oracle property: its asymptotic behavior is the same as of any efficient GMM estimator obtained under the a priori information that the true model were known. We propose data adaptive selection methods for thresholding parameter using multiple testing procedures. We determine the limiting null distributions of classical parameter tests and show the consistency of the corresponding block-bootstrap tests used in conjunction with thresholding GMM inference. We present the results of a simulation study for a misspecified instrumental variable regression model and for a vector autoregressive model with measurement error. We illustrate an application of the proposed methodology to data analysis of a real-world dataset.  相似文献   
7.
魏红珊 《民族学刊》2019,10(6):61-70, 127-129
风云激荡的近代“川边”,历任主政者的川边治理成效殊异:赵尔丰籍“平康三策”,锐意进取,开拓出广阔的川边境域,成功践行“固川保藏”方略。尹昌衡藉个人英雄主义维持短暂的绚烂;其后走马灯式的镇守使无法掌控川边局势,失地溃败;颇具政治韬略的刘文辉,妥善处理民族关系,稳固川边,促使西康成功建省。34年的川边治理为现代西南边疆治理留下了鲜活的经验教训,川滇藏结合部需要新的边疆治理统筹。  相似文献   
8.
Longitudinal studies are the gold standard of empirical work and stress research whenever experiments are not plausible. Frequently, scales are used to assess risk factors and their consequences, and cross-lagged effects are estimated to determine possible risks. Methods to translate cross-lagged effects into risk ratios to facilitate risk assessment do not yet exist, which creates a divide between psychological and epidemiological work stress research. The aim of the present paper is to demonstrate how cross-lagged effects can be used to assess the risk ratio of different levels of psychosocial safety climate (PSC) in organisations, an important psychosocial risk for the development of depression. We used available longitudinal evidence from the Australian Workplace Barometer (N?=?1905) to estimate cross-lagged effects of PSC on depression. We applied continuous time modelling to obtain time-scalable cross effects. These were further investigated in a 4-year Monte Carlo simulation, which translated them into 4-year incident rates. Incident rates were determined by relying on clinically relevant 2-year periods of depression. We suggest a critical value of PSC?=?26 (corresponding to ?1.4 SD), which is indicative of more than 100% increased incidents of persistent depressive disorder in 4-year periods compared to average levels of PSC across 4 years.  相似文献   
9.
本文基于期望效用最大化和L1-中位数估计研究了在线投资组合选择问题。与EG(Exponential Gradient)策略仅利用单期价格信息估计价格趋势不同,本文将利用多期价格信息估计价格趋势,以提高在线策略的性能。首先,基于多期价格数据,利用L1-中位数估计得到预期价格趋势。然后,通过期望效用最大化,提出一个新的具有线型时间复杂度的在线策略,EGLM(Exponential Gradient via L1-Median)。并通过相对熵函数定义资产权重向量的距离,进而证明了EGLM策略具有泛证券投资组合性质。最后,利用国内外6个证券市场的历史数据进行实证分析,结果表明相较于UP(Universal Portfolio)策略和EG策略,EGLM策略有更好的竞争性能。  相似文献   
10.
现阶段多种门诊挂号方式并存时,根据患者特性制定不同的等待时间策略尤为重要。本文考虑门诊挂号的三种渠道:直接排队挂号渠道、电话预约挂号渠道与O2O预约挂号渠道。在价格外生前提下,综合考虑患者的渠道偏好程度、时间敏感性与提前支付敏感性,基于效用理论构建患者的渠道选择模型。根据该模型推导得出不同市场条件下医院的需求,医院再据此制定患者的等待时间策略以达到利润最大化的目的。研究发现:当医院仅开通单一挂号渠道时,若患者的时间敏感度越大、渠道偏好程度越小,等待时间均越小;开通某两种挂号渠道时,还需考虑患者对两种渠道的偏好比例,偏好某种渠道的患者比例增加,选择该渠道的患者等待时间增加,选择另一渠道的患者等待时间减小;同时开通三种渠道时,最偏好某渠道的患者比例越大,选择该渠道的患者的等待时间也越大;在所有情况下,患者对提前支付的敏感度均不影响最优等待时间的制定。  相似文献   
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