生物教学中综合实践活动探究

在新一轮基础教育改革中诞生的综合实践活动是对活动课程的继承、发展与规范。因此，在生物课程中实施综合实践活动（简称生物综合实践活动）是实现六年制本科层次农村小学教师培养目标的重要教学改革措施之一。生物综合实践活动实施的原则包括实践性、学生自主性、教师有效指导和目标生成性原则；活动指导包括主题的确定、活动方案的设计、实施活动方案以及活动的交流与评价。     

鞍山 从废墟中站起的中国钢都

从共和国第一炉铁水、钢水诞生的那一刻算起,鞍钢为新中国钢铁工业创造了多个第一,被誉为"共和国钢铁工业长子"、 "新中国钢铁工业摇篮":1953年10月27日,第一根无缝钢管在鞍钢诞生,11月30日,第一根重轨在鞍钢问世; 12月19日,第一座现代化高炉流出第一炉铁水, "一五"期间,鞍钢成为新中国第一个大型钢铁生产基地,并涌现出孟泰、王崇伦等一批劳动模范……     

浅析水墨动画片的空间意识

水墨动画是中国传统水墨画与动画技术相结合的颇具民族特色的一种动画片种.它将中国传统水墨画的题材、笔墨节奏、审美空间意识引入到动画制作中,呈现"动画化"的水墨艺术.本文首先分析了传统水墨画所表现的节奏化自然、"阴阳"、"有无"的空间意识,再从属于电影范畴的水墨动画片的视听语言角度来阐述水墨艺术仅仅"动起来"还不够,还要达到真正意义上的"动画化",才能表现出比传统水墨画更有意蕴的空间意识.     

水族习惯法及其变迁——以贵州省三都水族自治县塘党寨为例

本文通过对贵州省三都水族自治县的一个典型水族村寨——恒丰乡塘党寨——的田野调查,描述了水族习惯法的表现形式、维护机制及其变迁。文章认为,水族地区社会经济的发展、国家权力的深入、长期的“送法下乡”活动以及宗教信仰等文化背景的深刻变化,是水族习惯法发生变迁的主要原因。研究这些变迁及其原因,对于理解和认识少数民族地区乃至整个农村的法治建设,具有不可忽视的作用。     

民族地区干部如何看待民族地区加快发展问题--云南地方干部问卷调查分析报告

新世纪中国民族地区面临的最大机遇是社会发展指标追赶的机遇,面临的最大挑战是人类贫困,从而使民族地区传统发展战略和宏观管理政策将面临着严峻的挑战。因此,本文依据具有民族地区代表性的云南地方干部调查问卷统计分析结果,通过考察民族地区发展战略的制定者和宏观管理政策的执行者——民族地区干部——对民族地区加快发展问题的认识和理解,总结出了一些有益的政策启示。     

试论民族地区普通中学多媒体课件制作及管理

运用现代教育技术提高教学效率是民族地区普通中学发展的必由之路。只有正确认识民族地区普通中学教育技术应用的背景,加强对此类教学资源的管理,才能使之更好服务于教学,提高民族地区教学实践活动的效率。     

法律的民族志写作与文化批评——论中国的法律人类学研究

本文针对目前我国对法律人类学的研究还没有形成独立的学科特色和明确研究方向、研究方法这一问题,提出可以以法律的民族志写作为其工具,进行法律的文化批评,用实践化的研究风格树立其独特的交叉学科形象。     

Inventory‐Based Dynamic Pricing with Costly Price Adjustment

We study an average‐cost stochastic inventory control problem in which the firm can replenish inventory and adjust the price at anytime. We establish the optimality to change the price from low to high in each replenishment cycle as inventory is depleted. With costly price adjustment, scale economies of inventory replenishment are reflected in the cycle time instead of lot size—An increased fixed ordering cost leads to an extended replenishment cycle but does not necessarily increase the order quantity. A reduced marginal cost of ordering calls for an increased order quantity, as well as speeding up product selling within a cycle. We derive useful properties of the profit function that allows for reducing computational complexity of the problem. For systems requiring short replenishment cycles, the optimal solution can be easily computed by applying these properties. For systems requiring long replenishment cycles, we further consider a relaxed problem that is computational tractable. Under this relaxation, the sum of fixed ordering cost and price adjustment cost is equal to (greater than, less than) the total inventory holding cost within a replenishment cycle when the inventory holding cost is linear (convex, concave) in the stock level. Moreover, under the optimal solution, the time‐average profit is the same across all price segments when the inventory holding cost is accounted properly. Through a numerical study, we demonstrate that inventory‐based dynamic pricing can lead to significant profit improvement compared with static pricing and limited price adjustment can yield a benefit that is close to unlimited price adjustment. To be able to enjoy the benefit of dynamic pricing, however, it is important to appropriately choose inventory levels at which the price is revised.     

Subgroup Analysis with Time‐to‐Event Data Under a Logistic‐Cox Mixture Model

Subgroup detection has received increasing attention recently in different fields such as clinical trials, public management and market segmentation analysis. In these fields, people often face time‐to‐event data, which are commonly subject to right censoring. This paper proposes a semiparametric Logistic‐Cox mixture model for subgroup analysis when the interested outcome is event time with right censoring. The proposed method mainly consists of a likelihood ratio‐based testing procedure for testing the existence of subgroups. The expectation–maximization iteration is applied to improve the testing power, and a model‐based bootstrap approach is developed to implement the testing procedure. When there exist subgroups, one can also use the proposed model to estimate the subgroup effect and construct predictive scores for the subgroup membership. The large sample properties of the proposed method are studied. The finite sample performance of the proposed method is assessed by simulation studies. A real data example is also provided for illustration.     

Estimating Abundance from Presence–Absence Maps via a Paired Negative‐Binomial Model

The estimation of abundance from presence–absence data is an intriguing problem in applied statistics. The classical Poisson model makes strong independence and homogeneity assumptions and in practice generally underestimates the true abundance. A controversial ad hoc method based on negative‐binomial counts (Am. Nat.) has been empirically successful but lacks theoretical justification. We first present an alternative estimator of abundance based on a paired negative binomial model that is consistent and asymptotically normally distributed. A quadruple negative binomial extension is also developed, which yields the previous ad hoc approach and resolves the controversy in the literature. We examine the performance of the estimators in a simulation study and estimate the abundance of 44 tree species in a permanent forest plot.