船长的勇气

很多年前,在辛辛那提州,我偶然走进一家书店,看到一个男孩儿在问老板是否有地理书出售。他大约12岁,看上去眉清目秀,可是衣衫褴褛。     

赤霉素对植物生长和开花的影响

赤霉素是在一种寄生于稻属作物的真菌(Gibbe-rella fujikuroi)分泌物中所发現的,是一种有很高生理活性的物質,这种物質能引起植物的高度发育。由于赤霉素的发現,創造了广泛的,試驗它对植物生長发育的影响及其对植物的生理表現与形态形成过程影响的基础。赤霉素对植物生長与开花影响方面的研究是特别值得注意的,最初就确定赤霉素对許多一年生或多年生植物幼苗起着显著的刺激作用。同时它对矮生型植物,例如豌豆及玉米等表現了特別强烈的反应。之后也証实了赤霉素对植物的开花也起着强烈的作用。这种試驗得出了显著的成績,不論作試驗的植物的种不同,以及进行这些試驗的条件互异,所取得的結果都是完全吻合的。     

用鸡胚心脏进行器官培养的实验

本文所述的实验是想告诉学生怎样用器官培养来研究发育问题,而此实验只需将目前许多普遍生物实验课中都进行的活鸡胚一般观察的实验,加以延伸即可。先让学生观察制作孵化48小时鸡胚标本的全过程,使他们熟悉鸡胚的介剖:要他们特别注意静脉窦、心房、心室和主动脉弓的位置。接下来发给学生一个生活了55—72小时的鸡胚,按照实验指导(许多实验手册中的指导是适用的,如Evert. Saigo,和Eichhorn 1979 Eberhard,Arms,和Camp 1927),把鸡胚     

麦田里的守望者(节选)

“什么 ?”我跟老菲芘说。她跟我说了些什么，可我没听清楚。 　　“你连一样东西都想不出来。” 　　“嗯，我想得出来。嗯，我想得出来。” 　　“呃，那你说出来。” 　　“我喜欢艾里，”我说，“我也喜欢我现在所做的事。跟你一起坐在这儿，聊聊天，想着一些玩艺儿──”“艾里已经死啦──你老这么说的 !要是一个人死了，进了天堂，那就很难说──”“我知道他已经死啦 !你以为我连这个也不知道 ?可我依旧可以喜欢他，对不对 ?不可能因为一个人死了，你就从此不再喜欢他，老天爷──尤其是那人比你认识的那些活人要好一千倍。” 　　…     

Specifications of OCLC CJK Bibliographic Records And the Adoption of CJK Records from Asia

OCLC Online Computer Library Center, the largest library automation network in the world, links nearly 20,000 libraries in the Uaited States and 60 other countries and territories. Introducing a library automatian network of Chinese, Japanese, and Korean(CJK) characters in 1986, OCLC operates the largest CJK library network in the world in terms of the member of online CAK institutional asers. As of January 1, 1995, OCLC had 40 CJK users in the United States, Aastralia, Hong Kang and Taiwan. As of October 1, 1994, there were nearly 850, 000 unique CJK bibliographic records in the OCLC database. OCLC is interested in sharing the CJK bibliographic records, especially in loading CJK records created in Asia into the OCLC database. To this end, OCLC has entered into an agreement with the National Central Library, Taiwan; the National Library of China, and Waseda University, Japan, and is in negotiation to load the Japan-MARC records. Sharing of CJK bibliographic records between libraries in Asia and those in the United States is a complex task as the CJK records created in Asia and those created in the United States are not compatible. This paper explains the specifieatioas of the OCLC CJK records, and lists eight areas where the incompatibility exists. The following five areas of incompatibility are due to different cataloging practices: 1. AACR2; 2. name and subject authorities;3.romantzation; 4.subject headings; and 5.ctassification schemes. Three additional areas of incompatibility are technical in nature; 6.MARC format; 7.character set; and 8.internal code.     

DES exposure: implications for childbearing

From the 1940s to the early 1970s, diethylstilbestrol (DES), an oral, nonsteroidal synthetic estrogen, was prescribed by physicians to 2-6 million women in the US alone to prevent miscarriages. In 1970, and article documented the correlation between in utero DES exposure and development of a rare vaginal cancer, clear-cell adenocarcinoma. In 1971, US Federal Drug Administration banned the drug from use during pregnancy. Since then, controlled studies have proven that administration of DES was associated with increased spontaneous abortions, premature delivery, complications during delivery, and neonatal deaths. DES-exposed daughters in reproductive age faced increased rates of infertility, spontaneous abortion, ectopic pregnancy, and premature delivery. DES-exposed daughters may suffer more pelvic inflammatory disease and dysmenorrhea. A 1988 study related the infertility experience of 796 daughters born to mothers who took part in a double-blind, controlled study of DES use during pregnancy at a Chicago hospital in 1951 and 1952. In early 1986, primary infertility was reported by 33% of the DES-exposed daughters as opposed to 14% of the unexposed subjects. However, 81% of pregnant DES daughters have at least one full-term live birth. Uterine abnormalities including a T-shaped or hypoplastic cavity, a septate uterus, intrauterine adhesions, or irregular uterine margins were documented in 46% of the DES-exposed daughters with primary infertility. Vaginal adenosis is reported to occur in 30%-90% of DES-exposed daughters. Cervical hypoplasia and shortened cervical structure are the primary cervical abnormalities. In addition, for 10 years researchers have observed certain alterations in the immune systems of DES-exposed women. Most physicians recommend alternative birth control methods to oral contraceptives to avoid an additional exposure to synthetic estrogens.     

电脑杀手(4)

詹妮和爸爸妈妈以及艾普丽尔都跑到院子里,但是大门上也有了电流。 凯乐带领詹妮和艾普丽尔来到地下室,拉下了中断电源的闸刀。 凯乐先生又接通了电源,詹妮插上了电脑插头。p一, \,-、/_ 0’%端麓嚣=掌蒂$≯一一毒;蠢囊穰毫鱼Il蕊囊i毫誊g蠹囊毫凳蕊 我向你发誓!向日葵。 道格马上拔掉插头。’～‰.0觚妻潮删獭佩只是个杪—’剽圳电脑游戏, 我们它也许是已经把它零了。彳陷在电脑渊.主莩。“”。 道格拿出带来的一块强大的电磁铁和变压器,连接在电源上。。 这样做可以删去记忆,但对电脑也会有损伤。 别担N心,孩子,l我们可以l修理或换. /一…     

维珍之王理查德·布兰森

无论理查德·布兰森在任何时候做任何事情,他都会相当引人注目。你已经见过那个形象了。他咧着嘴笑,那狮子头的发型让年届56岁的他看起来就像一个在船头迎风破浪的汉子。他的个子不高,但人们都说你不会注意到这一点,因为他从不在一个地方久留到让你有机     

加拿大教育局长作用的变化

在过去的好几年里,我一直把研究和实际工作的重点放在教育局长的作用,以及这种作用和组织效能(organiza之间的关系问题上。对我来说,有一点是相当明确的,即CEO和校方董事(的作用已经起了变化。并且从多方面来看,这种变化还导致了CEO与学校董事会(之间关系的改变。作为一名研究人员,尤其重要的是,作为一名热衷于对CEO和校方董     

论普通中学学生美育的实质、原则和体系

美育的实施就是要发展和提高儿童的社会主义艺术审美力,帮助他们积极抵制资产阶级的美学观念和审美力。所谓审美力就是指洞察美的技能,并对它作出客观评定的能力.