It is possible to make specific complementary DNA’s (cDNA’s)that can serve as molecular probes to seek out the messenger RNA’ s (mRNA’ s) of the peptide hormones. If brain cells are making the hormones,the cells will contain these Mrna’S.

If the products the brain cells make resemble the hormones but are not identical to them,then the cDNA’s should still bind to these mRNA’s,but should not bind as tightly as they would to mRNA’s for the true hormones.

The molecular approach to detecting peptide hormones using cDNA probes should also be much faster than the immunological method because it can take years of tedious purifications to isolate peptide hormones and then develop antiserums to them.

Nevertheless, researchers of the Pleistocene epoch have developed all sorts of more or less fanciful model schemes of how they would have arranged the Ice Age had they been in charge of events.

This succession was based primarily on a series of deposits and events not directly related to glacial and interglacial periods,rather than on the more usual modern method of studying biological remains found in interglacial beds themselves interstratified within glacial deposits.

There have been attempts to explain these taboos in terms of inappropriate social relationships either between those who are involved and those who are not simultaneously involved in the satisfaction of a bodily need,or between those already satiated and those who appear to be shamelessly gorging.

Many critics of Family Bronte’s novel Wuthering Heights see its second part as a counterpoint that comments on,if it does not reverse,the first part,where a "romantic" reading receives more confirmation.

Granted that the presence of these elements need not argue an authorial awareness of novelistic construction comparable to that of Henry James, their presence does(15) encourage attempts to unify the novel’s heterogeneous parts.

This is not because such an interpretation necessarily stiffens into a thesis(although rigidity in any interpretation of this or of any novel is always a danger),but because Wuthering Heights has recalcitrant elements of undeniable power that,ultimately,resist inclusion in an all-encompassing interpretation.

The isotopic composition of lead often varies from one source of common copper ore to another,with variations exceeding the measurement error;and preliminary studies indicate virtually uniform is topic composition of the lead from a single copper-ore source.

More probable is bird transport,either externally,by accidental attachment of the seeds to feathers,or internally,by the swallowing of fruit and subsequent excretion of the seeds.

明朝统治中国276年,被人们描绘成人类历史上治理有序、社会稳定的最伟大的时代之一。

这一时期,手工业的发展促进了市场经济和城市化。大量商品,包括酒和丝绸,都在市场销售。同时,还进口许多外国商品,如时钟和烟草。

北京、南京、扬州、苏州这样的大商业中心相继形成。也是在明代,由郑和率领的船队曾到印度洋进行了七次大规模探险航行。还值得一提的是,中国文学的四大经典名著中有三部写于明朝。

宋朝宋朝始于960年,一直延续到1279年。这一时期,中国经济大幅增长,成为世界上最先进的经济体,科学、技术、哲学和数学蓬勃发展,宋代中国是世界历史上首先发行纸币的国家。