细胞与温度

Cells and Temperature 细胞与温度 Cells cannot remain alive outside certain limits of temperature and much narrower limits mark the boundaries of effective functioning. Enzyme systems of mammals and birds are most efficient only within a narrow range around 37C;a departure of a few degrees from this value seriously impairs their functioning. Even though cells can survive wider fluctuations the integrated actions of bodily systems are impaired. Other animals have a wider tolerance for changes of bodily temperature.

For centuries it has been recognized that mammals and birds differ from other animals in the way they regulate body temperature. Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology still reflects the old division into “warm-blooded” and “cold-blooded” species; warm-blooded included mammals and birds whereas all other creatures were considered cold-blooded. As more species were studied, it became evident that this classification was inadequate. A fence lizard or a desert iguana—each cold-blooded----usually has a body temperature only a degree or two below that of humans and so is not cold. Therefore the next distinction was made between animals that maintain a constant body temperature, called home0therms, and those whose body temperature varies with their environments, called poikilotherms. But this classification also proved inadequate, because among mammals there are many that vary their body temperatures during hibernation. Furthermore, many invertebrates that live in the depths of the ocean never experience change in the depths of the ocean never experience change in the chill of the deep water, and their body temperatures remain constant.

细胞只能在一定的温度范围内存活，而进一步保证它们有效工作的温度范围就更小了。哺乳动物和鸟类的酶系统只能在37℃左右的很小范围内才能有效工作。与此 相差仅几度的温度都会大大削弱它们的工作效率。尽管温度变化更大时细胞仍能存活，但机体系统的整体运行能力却被削弱了。其它动物对体温的变化有更强的适应 性。

几个世纪以来，人们就认识到哺乳动物和鸟类调节体温的方式与其它动物不同。随着时间的推移，人们对这种差异的描述越来越精确和有意义，但是"暖血动物" 和"冷血动物"这一古老的分类方式至今仍在大众词汇中有所反映。暖血动物包括哺乳动物和鸟类，其它动物统统被视为冷血动物。但是对更多物种进行的研究表明 这种分类显然是不适当的。美洲一种小型蜥蜴和沙漠鬣蜥同属冷血动物，但实际上它们的体温通常只比人类的体温低1～2度，因此并不是真正的冷血。因此又出现 了恒温动物(即保持恒定体温的动物)和变温动物(即体温随外界环境的变化而改变的动物)这一区分方式。但这种分类也不恰当。因为有不少哺乳动物在冬眠期间 会改变体温，而许多生活在深海的无脊椎动物在寒冷的深海水域中体温并不变化，而是恒定的。 Movie Music 电影插曲 Accustomed though we are to speaking of the films made before 1927 as “silent”, the film has never been, in the full sense of the word, silent. From the very beginning, music was regarded as an indispensable accompaniment; when the Lumiere films were shown at the first public film exhibition in the United States in February 1896, they were accompanied by piano improvisations on popular tunes. At first, the music played bore no special relationship to the films; an accompaniment of any kind was sufficient. Within a very short time, however, the incongruity of playing lively music to a solemn film became apparent, and film pianists began to take some care in matching their pieces to the mood of the film.

As movie theaters grew in number and importance, a violinist, and perhaps a cellist, would be added to the pianist in certain cases, and in the larger movie theaters small orchestras were formed. For a number of years the selection of music for each film program rested entirely in the hands of the conductor or leader of the orchestra, and very often the principal qualification for holding such a position was not skill or taste so much as the ownership of a large personal library of musical pieces. Since the conductor seldom saw the films until the night before they were to be shown(if indeed, the conductor was lucky enough to see them then), the musical arrangement was normally improvised in the greatest hurry.

To help meet this difficulty, film distributing companies started the practice of publishing suggestions for musical accompaniments. In 1909, for example, the Edison Company began issuing with their films such indications of mood as “ pleasant”, “sad”, “lively”. The suggestions became more explicit, and so emerged the musical cue sheet containing indications of mood, the titles of suitable pieces of music, and precise directions to show where one piece led into the next.

Certain films had music especially composed for them. The most famous of these early special scores was that composed and arranged for D.W Griffith’s film Birth of a Nation, which was released in 1915.

尽管我们习惯于将1927年以前的电影称为"无声电影"，但是就无声这个词完整的意义上来说，电影从未真正的无声过，从最初开始音乐就被视为必不可少的伴 奏。当卢米埃尔的电影在1896年2月美国首届影片公映展览上放映的时候，影片便用当时的流行曲临场钢琴伴奏。最初，这些音乐伴奏与电影没有什么特别的关 系，用什么曲子伴奏都行。但在很 短的时间内，为一部庄重的影片演奏快活的音乐所产生的不协调感变得显而易见，因此钢琴家们开始注意将自己的作品与影片的情调结合起来。 随着影剧院在数量上与重要性上的不断增长，在一些场合，除了钢琴师外，还要加上小提琴师，或许还有一位大提琴师。较大的影剧院里还组成了小型的管弦乐队。 在很长的时间内，为各部影片选择配乐完全掌握在乐队指挥或队长手中，而通常把持这种职位的资格不是技巧或鉴赏品味，而是拥有一个大的音乐作品的个人收藏。 因为直到电影上映的前一天晚上乐队指挥才能看到影片(如果这个指挥真正有幸能够看到影片的话)，音乐安排通常是在非常匆忙的情况下临场进行的。 为了解决以上的困难，电影发行公司开办了为音乐伴奏印制提示单的业务。例如1909年爱迪生公司开始将一些诸如"喜悦的"、"悲伤的"、"活泼的"之类表 明影片情调特征的提示与影片一起发行。这些提示逐渐变得更加具体，并且出现了包括影片情调说明、适用乐曲名称和乐曲转换点等内容的配乐说明单。某些影片拥 有专门为其创作的音乐。 这些早期特创乐谱中最著名的便是为D.W.格雷夫斯1915年上映的影片《一个国家的诞生》所创作的音乐