超冷的水

又发现了两种新水。要是没有水，我们原本不会来到这个世界。水的热容量在-45℃时应该变成无穷大。水的其它特性似乎也变得一团糟，就像水经历了某种灾变一样，为什么？如果想象在太平洋之下11公里处的马里亚那海沟中即在海洋最深之处的高压之下，人还能生活，便会看到这是一个寂静的、永远黑暗的世界，压力高达1000个大气压。那是一座相当于洋底每平方米承受1000吨压力的海水之增。在如此恶劣的条件下，生存必定不易。然而现在有些物理学家相信在这样高的压力下甚至水本身可能也难于保持不变。他们认为如果在以上压力下水若能保持不变即仍…     

物理学阻止了克隆

无论存活与否 ,制造出与本身完全一致的复制品是不可能的     

The role of sex steroids in the acquisition and production of birdsong

Male birdsong is generally regarded as a secondary sexual characteristic under the control of gonadal steroids. Song typically waxes and wanes with the seasonal cycle of testicular growth and regression and decreases after adult castration. Testosterone therapy reinstates song, induces it in females, augments it in intact males, and spring testosterone profiles correlate with seasonal song production. Thus, testosterone has been viewed as a major factor in song acquisition and production acting either directly, or after aromatization within the brain. We show here, however, that song learning and early phases of the development of singing both take place in castrated male birds with no significant levels of testosterone in their blood plasma. Testosterone seems to be required for song crystallization, however. Oestradiol was unexpectedly still present after castration, evidently from a non-testicular source, throughout the period of male song acquisition.     

Glycine absorption from the small intestines of rats after secondary infections with Eimeria nieschulzi

A second (challenge) infection of Eimeria nieschulzi in clinically immune rats did not produce weight gain depression but caused a decrease in the absorption of glycine from the ileum. The malabsorption due to challenge was equivalent to that caused by the primary infection which did cause weight loss.