逃不掉的逃兵

这是我不训练的第一个暑假，它比想象中轻松，又比想象中难熬。二十四个小时的空调，二十四个小时的昏昏欲睡。想到曾经的队友们在此刻的展光笼罩下热身，在此刻的骄阳下冲刺，在此刻的塑胶跑道上压腿。再看到现在的自己吃着冰淇淋，拿着遥控器慢悠悠地调台。就觉得自己像逃离一线、回家投亲、享受资产阶级生活的逃兵。     

论缓冲溶液的制备

凡实验室涉及到生物学和化学的水溶液体系时,pH和离子强度(I)是两个极为重要的可变量。由于酸—碱混合物的存在,这两个参量往往相互依赖。控制pH值的通常方法是使用缓冲剂。它们是由那些对于溶液离子行为影响不大、且不活泼的稳定电解质来配制的。本文提出的方法适用于计算某种酸及其盐混合物的pH值和离子强度;或与此相反,用于计算配制预知pH值和离子强度(I)所需酸及其盐的相当量。这种计算方法很实用,具有启发性和直观教学的价值,在许多普通的可编程序计算器上容易完成。     

关于理科教育的一种理论根据

关于理科教育的任何一种合理的理论根据必须包括教育目的、学科和一种学习的模型。 教育目的 关于学校应达到的目的,曾是许多论文的主题,但它们中间存在着争论和分歧。对这些争论本文将不涉及,但有一个是例外;这个例外就是美国教育政策委员会1961年报告书中扼要陈述的,即认为教育的中心目的是教学生思维。这一任务在该委员会的“美国教育的中心目的”论文中详细地阐述如下:     

项目规模和软件维护的生产率——软件维护中的规模经济的经验理论

尽管适当的项目规模在软件开发时是信息系统管理员所关心的问题,但他们认为软件维护项目的规模对软件维护生产率没有影响。这种观点忽视了预修改策略,例如把相似的维护要求集中起来形成一个较大的项目,在提高效率方面的作用。我们对一个国有大型零售公司的研究中发现了软件维护工程的项目规模和生产率之间的关系。我们采用数据包络分析(DEA)的非参数方法来估计软件维护项目的投入和产出之间的函数关系,并且确定了这个公司的所有维护项目中生产率最高项目的规模值。我们也采用了以DEA为基础的试探法来测试这些项目中规模收益的存在。我们的结论是:在这些软件维护项目中,明显地存在规模经济。达到最高生产率的项目的规模大于样品项目中90%的项目的规模。这个结论说明:如果在这个公司中,将较小的项目集合成较大的项目予以实施就有可能提高软件维护的生产率。     

Features of the Formation of Multi-view Autostereoscopic Image without Vertical Parallax

1.Introduction The reproduction systems of 3D images without using eyeglasses and other special accessories has always attracted attention and aroused great interest of developers and consumers of such equipment because of totally accurate image and method of its presentation.Such systems can be used and are already partially used in advertising,television,different devices (i.e.smartphones,tablet computers),at the exhibitions,etc.,as well as in various technical applications,training systems,simulators,etc.     

爸爸妈妈 你们为什么不吻我呢

小女孩辛迪和她的爸爸妈妈生活在一起。她的家庭并不富裕,但一家人非常和睦,生活也很幸福。然而生活中好像还存在着什么缺憾,辛迪没意识到。辛迪9岁那年,第一次在外面过夜,那是在她的好朋友黛比家。睡觉前黛比的妈妈进来,分别轻轻地吻了吻她们的额头,并向她们道了“晚安”。“我爱你,黛比。”当黛比的妈妈吻过黛比之后,轻声地说道。“我也爱您,妈妈。”黛比喃喃地应道。面对此情此景,辛迪不禁大吃一惊,心中久久不能平静。从她记事以来,从来就没有人吻过她,还向她道晚安、说爱她之类的话。整整一夜,她的眼前始终闪现着黛比的妈妈轻吻黛比时的…     

高中-大学双学分课程体制的陷阱

2005年6月,俄勒冈立法机关通过一项支持建立高校毕业速成班的法案,该法案要求在全州范围内建立一种高中-大学双学分课程体制,允许高中三、四年级的学生选修高中和大学/学院入学考试都适用的课程。双学分课程计划的典型特征是高中学生选修社区学院的课程(社区学院在高中或学院内开课),学生在社区学院修完两年课程、取得结业证书之后可以转学到四年制大学攻读学士学位。双学分课程计划在美国越来越受欢迎。华盛顿州立法机关早在1990年就制定了一个名为《起跑线》(Running Start)的计划,允许就读11和12年级的学生自由选修该州34所技术与社区学…     

FLOSSWorld全球调查结果显示服务器更多使用开源软件

FLOSSWorld调查的主体由5部分构成,包括:个人(Private sector)、政府(Government sector)、开源社区参与者(Open Source participants community)、高校管理者(Heigher Education Institutes——Administrators)、高校信息部门主管(Heigher Education Institute——ITManagers)     

Synthetic and biological studies on a cyclopolypeptide of plant origin

Objective: A natural cyclic peptide previously isolated from Citrus medica was synthesized by coupling oftetrapep-tide units Boc-Leu-Pro-Trp-Leu-Ome and Boc-Ile-Ala-Ala-Gly-Ome after proper deprotection at carboxyl and amino terminals followed by cyclization of linear octapeptide segment.Methods: Solution phase technique was adopted for the synthesis of cyclooctapeptide--sarcodactylamide.Required tetrapeptide units were prepared by coupling of Boc-protected dipeptides viz.Boc-Leu-Pro-OH and Boc-Ile-Ala-OH with respective dipeptide methyl esters Trp-Leu-Ome and Ala-Gly-Ome.Cyclization of linear octapeptide unit was done by p-nitrophenyl ester method.The structure of synthesized cyclopolypeptide was elucidated by FTIR,1H NMR,13C NMR,FABMS spectral data and elemental analysis.The newly synthesized peptide was evaluated for dif-ferent pharmacological activities including antimicrobial,anthelmintic and cytotoxic activities.Results: Synthesis of sarcodac-tylamide was accomplished with >78% yield utilizing dicyclohexylcarbodiimide (DCC) as coupling agent.Newly synthesized peptide possessed potent cytotoxic activity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines,in addition to moderate anthelmintic activity against earthworms Megascoplex konkanensis,Pontoscotex corethruses and Eudrilus sp.Moreover,cyclopolypeptide displayed good antimicrobial activity against pathogenic fungi Candida albicans and Gram-negative bacteria Pseudomonas aeruginosa,in comparison to standard drugs griseofulvin and ciprofloxacin.Conclusion: Solution phase technique employing DCC and triethylamine (TEA) as base proved to be effective for the synthesis of natural cyclooctapeptide.N-methyl morpholine (NMM) was found to be a better base for the cyclization of linear octapeptide unit in comparison to TEA and pyridine.     

Developmental links of very early phonological and language skills to second grade reading outcomes: strong to accuracy but only minor to fluency

The authors examined second grade reading accuracy and fluency and their associations via letter knowledge to phonological and language predictors assessed at 3.5, 4.5, and 5.5 years in children in the Jyv?skyl? Longitudinal Study of Dyslexia. Structural equation modeling showed that a developmentally highly stable factor (early phonological and language processing [EPLP]) behind key dyslexia predictors (i.e., phonological awareness, short-term memory, rapid naming, vocabulary, and pseudoword repetition) could already be identified at 3.5 years. EPLP was significantly associated with reading and spelling accuracy and by age with letter knowledge. However, EPLP had only a minor link with reading fluency, which was additionally explained by early letter knowledge. The results show that reading accuracy is well predicted by early phonological and language skills. Variation in fluent reading skills is not well explained by early skills, suggesting factors other than phonological core skills. Future research is suggested to explore the factors behind the development of fast and accurate decoding skills.