梅叶蜂的初步研究

<正> 梅叶蜂Nematus sp.属膜翅目,叶蜂科(Tenthredinidae)、丝叶蜂亚科(Nematinae),是四川省梅产区叶片上重要害虫之一。国内对该虫尚无报道。我们于1984～1985年在四川省大邑县邮江区对该虫作了初步观察和研究,现将结果整理如下。     

怎样做好高中生物新教材中的实验(二)

（续１９９９年第３４卷第１期第３０页）［实验７］影响酶活性的实验１实验的准备工作实验需要的冰水条件，教师应根据学生人数的多少，提前几天制备相应数量的冰块。２实验成功的关键及注意事项实验成功的关键是操作顺序的正确。本实验是验证温度和ｐＨ对酶活性的影响，...     

Diseases and deaths; a summary of data from the Los Angeles County General Hospital, 1918 to 1948

Classification of the 2,557,035 diagnoses made in 1,168,139 different patients at the Los Angeles County General Hospital in the period 1918-48 has been compiled according to the new International List of Causes of Diseases and Death. Similar tabulation of the 377,776 diagnoses made in the 112,409 patients who died while in the hospital reflects the fatality rates associated with these diagnoses. Striking differences are shown in the incidence and fatality rates in the various conditions and great changes have occurred in both during this time. Defects and sources of error in these data are recognized, but they offer a wealth of valuable material for further study and interpretation.