鳥类的干制

在生物学課堂教学中,直观教具的演示,是教学和教育工作中不可缺少的一部分。但生物教师却不能每一堂都能安排好必要的教具。这是由于教师不会自己制备教具的緣故。我从事各种直观教具,特别是对爬行类、鳥类与哺乳类动物的干制标本,已有十余年的經驗。本文將介紹应用40%的福尔馬林溶液注射于动物屍体的方法干制鳥类标本的经验。剥制法虽比干制法效果好一些,但时間需要较长;此外,剥制时所用的砒霜或砷酸钠这些毒物,往往有危險,而且这些毒物又不易买到。干制只需用福尔馬林,危險性少,而每个藥房也都可买到。干制不同于剝制,以后会干縮变小,但形狀颜色不变。在一定的保存条件(玻璃柜中)下和适当的保养(每一年撒上一层萘粉、六六六药剂等),干制标     

对医预科学校学习目标的建议

最近，美国医学院校协会（ＡＡＭＣ）发表了医学院校学习目标报告（ＭＳＯＰ）以协助各院校培养“能够满足社会需求”的新一代医生。两份ＭＳＯＰ报告总体上是鼓励开发医预科学校的学习目标，建立这种学习目标能确保这些未来的医学生较好地面对医学院校的课程，这些课程已经限定了他们在四年中所学的内容。那些不能在标准医学课程中扩展的教育要素能在本科生教育中予以提供，医预科教育也能包含这些内容，例如：通讯技能，写作和演讲；医学的心理社会方面内容，从伦理学到医患关系的延伸；统计学，包括介绍以证据为基础的医学的概论；信息学…     

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.     

Recognition of facial emotions among maltreated children with high rates of post-traumatic stress disorder

OBJECTIVE: The purpose of this study is to examine processing of facial emotions in a sample of maltreated children showing high rates of post-traumatic stress disorder (PTSD). Maltreatment during childhood has been associated independently with both atypical processing of emotion and the development of PTSD. However, research has provided little evidence indicating how high rates of PTSD might relate to maltreated children's processing of emotions. METHOD: Participants' reaction time and labeling of emotions were measured using a morphed facial emotion identification task. Participants included a diverse sample of maltreated children with and without PTSD and controls ranging in age from 8 to 15 years. Maltreated children had been removed from their homes and placed in state custody following experiences of maltreatment. Diagnoses of PTSD and other disorders were determined through combination of parent, child, and teacher reports. RESULTS: Maltreated children displayed faster reaction times than controls when labeling emotional facial expressions, and this result was most pronounced for fearful faces. Relative to children who were not maltreated, maltreated children both with and without PTSD showed enhanced response times when identifying fearful faces. There was no group difference in labeling of emotions when identifying different facial emotions. CONCLUSIONS: Maltreated children show heightened ability to identify fearful faces, evidenced by faster reaction times relative to controls. This association between maltreatment and atypical processing of emotion is independent of PTSD diagnosis.     

关于猫、黄金、老头和金字塔的三个不同故事

两位考古专家一同前去参观金字塔,晚上便住在开罗市郊的一家小旅馆里,一个人留在房间里面写工作日记,另一个人就上街闲逛。他在路边发现有一个老妇人在卖一只黑色的工艺猫,要价1000元。他忽然发现这只猫的两只眼睛竟是两颗大     

基于国家教育标准的地理教材

为进一步增强美国地理教育。我们要做的许多事情之一就是改进教材的质量。其中最主要的三个方面的任务是:(1)开发优良的教材,(2)利用教师联盟的在职培训网络和职前教育计划培训教师使用这种新教材,(3)通过提供强有力的课程指导,特别是将教材与师资培训和基于国家     

心路历程--流逝的岁月

Old age gives us the privilege to explore, to innovate, to challenge.Dear Friends,This is our twelfth monthly column and the first-year anniversary of our conversation together in the pages of Overseas English. We call this a milestone in English. Is there a Chinese word for it?I would like to begin our column with one of my own poems.     

Failure to obtain value enhancement by within-trial contrast in simultaneous and successive discriminations

The present research tested the generality of the “work ethic“ effect described by Clement, Feltus, Kaiser, and Zentall (2000). In Experiment 1, we trained 10 pigeons on a pair of either simultaneous or successive discriminations. One discrimination followed a high-effort requirement (20 pecks to the center key) and the other followed a low-effort requirement (1 peck). Contrary to Clement et al.’s results, we found that preferences between the S⁺ and S⁻ stimuli in transfer tests depended on the event that initiated the trial: Pigeons preferred the stimulus from the baseline discrimination whose initiating event was most dissimilar from that preceding the test trial. Preferences were similar but less extreme in the successive condition. In Experiment 2, we investigated whether test preferences depended on the amount of training. A total of 12 pigeons were trained on a pair of simultaneous discriminations, except that test sessions were scheduled after every three baseline sessions. Preferences increased across test sessions but were similar to those in Experiment 1. Together with Vasconcelos, Urcuioli, and Lionello-DeNolf (2007a), our study represents a second failure to replicate Clement et al.’s work ethic effect. The finding that preference depends on the event that initiates the test trial suggests that choice probes may not provide unambiguous assessments of stimulus value.