细胞遗传工程:植物育种的一项新技术吗?

有一项道传工程的新技术,它不象重组DNA技术那样被广为宣传,那就是通过无性细胞融合来转移遗传物质。采用这一有前途的方法交换整块基因,不必象在重组DNA技术中那样需事先进行鉴定和分离。今后几年内,这类方法可使基因块(geneblock)从一物种转侈到另一物种成为可能,例如可以把杂草的抗除草剂抗性赋予农作物。     

教育工作者及其报酬： 政策、实施与系统协调问题（上）

本文从管理学和政策学的视角,探讨了公立学校教师薪酬改革的问题.文章在回溯了教师薪酬制度历史沿革的基础上,分析了当前教师薪酬体制的结构及其对个人和组织层面的消极后果.作者认为,绩效工资改革是增强学校效能、促进学生成绩提高的有效途径;改革的未来取决于一系列多变因素之间的复杂互动,而系统的整合与协调是确保绩效工资计划有效并持久推进的关键.     

Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors

The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.     

Disability in higher education: a position paper

Leadership in education, particularly special education, implies both knowledge and application of professional behaviors, decisions, and ethics within the field. University students look for best practices in education to be modeled by faculty; this, in turn, underscores a fundamental belief in inclusionary principles. Such modeling is important on every level in teacher education programs, particularly special education programs. The higher a student's level (i.e., undergraduate vs. doctoral), the more notice that student will take of disparities between rhetoric and actions. While reflective practices are explicitly taught in teacher preparation programs to enable professionals to reflect on their own personal and professional practices, teacher education faculty need to employ the same strategy to ensure that they are indeed modeling the practices they teach. This position paper documents the impressions of a doctoral cohort in special education in terms of inclusionary practices demonstrated in a real-life context.     

Inquiry-based learning in China: Do teachers practice what they preach, and why?

China is undergoing an education reform that calls for a change from a rigid, fixed curriculum and didactic pedagogy to a more flexible, school-based curriculum and more inquiry-based pedagogy. This study investigated the extent to which Chinese middle and high school teachers (a) endorse an inquiry-based approach and underlying learning principles, (b) practice this mode of teaching, and (c) believe that the approach is practically viable in the current educational contexts in China. A structured survey was developed to solicit Chinese teachers’ responses to the above three issues. A total of 582 valid responses were collected, representing middle and high schools in different geographic locations. The results show that Chinese teachers are receptive to inquiry-based pedagogy but find practical constraints in fully implementing it. Several cultural and pragmatic reasons are explored. Policy implications are discussed with respect to teacher education/development, capacity building for the new pedagogy, and teaching/evaluation alignment. Finally cultural issues are discussed regarding using inquiry-based learning to enhance critical thinking and nurture independent thinkers.     

氟

不寻常的酸苏联的乌拉尔是富饶的地区。在乌拉尔山脉的内部蕴藏着大量的各种各样的有用的矿物。沿着流经乌拉尔地区的兹拉托乌思金斯基的米亚斯河的右岸绵延着不太高的依立敏斯基山脉。在乌拉尔山脉里天然造成了一个蕴藏着稀有矿物(如黄玉、钛铁矿和其他矿物)的珍奇的仓库。萤石是具有最多样颜色的一种矿石。在阳光照耀下,它的各色晶体闪耀得好像春天里的花朵一样。在萤石的结晶体中显现出光谱中所有的颜色—从红色到紫色。然而萤石值得注     

提心吊胆的华尔街

The war in Iraq, terrorism, rising oil prices-and now the threat of higher interest rates-are all preying on the market. There comes a point in virtually every bull market when     

创业者的白金思维法

任何一个复杂的问题都是近乎无数的事实和关系的组合。商业行为尤其受到方方面面的影响,包括过去的、非逻辑的和不可知的事物的影响。这种复杂性又因目标不同与服务于各种各样的顾客的需要而更加盘根错节,而顾客的许多目标不得不经过权衡后放弃。在这样复杂的条件下解决问题需要井井有条的、系统的方法以试图优化最后的决定。     

丝绸之路经济带区域创新与区域信息化的耦合协调性分析

通过计算2006—2014年丝绸之路经济带九省(区、市)的区域创新及信息化评价指数,进而构建耦合协调模型,算出二者之间的协调度,并测算区域间和区域内协调度的差异变动,得到如下结论:(1)丝绸之路经济带各地区的区域创新水平与信息化水平整体不高,且区域创新要滞后于区域信息化(2)各地区的区域创新与区域信息化发展呈现出高水平耦合共振状态,但是当考虑二者的综合发展水平时,二者的耦合协调发展程度虽然逐年向好,但发展状况参差不齐,考察期内尚未达到优质协调状态;(3)经济带整体协调度差异先扩大后缩小,地区内差异是总体差异的主要贡献方,而地区内的差异又主要来自于西北地区的贡献。在分析和解释相关结论的基础上,提出若干政策建议。     

引导基金参股方式对创投机构后续募资的影响

本文通过私募通数据库搜集数据构造匹配样本,使用logit模型、Cox模型和多元线性回归模型,从后续募资的可能性、时间间隔、募资规模三个方面,实证分析引导基金单独参股和联合参股这两种参股方式对创投机构后续募资的影响。研究发现:(1)引导基金联合参股可以促进创投机构后续募资,而单独参股则不能。(2)引导基金无论联合参股高声誉创投机构还是低声誉创投机构,都会促进其后续募资。(3)引导基金联合参股非国有背景创投机构可以促进其后续募资,但联合参股国有背景创投机构则不能促进其后续募资。