盈余管理理论研究综述

本文主要梳理国内外学者对盈余管理的理论研究,从对其概念的差异,到存在的原因,盈余管理的目的、方式,及其盈余管理的利弊都做了全面的回顾与探讨,以期为从事盈余管理理论与实证研究的学者提供价值参考。     

办公自动化的发展

介绍国内外办公自动化现状及其发展概况，进一步说明多媒体、多文种、开放性等是未来办公自动化应具有的基本特征．     

铅锌矿采矿废物污染对土壤原生动物的影响

对甘肃省成县王家山严家沟铅锌矿采矿废物污染土壤及对照土壤中的原生动物进行了研究。结果表明，铅锌矿采矿废物污染对原生动物群落有很大影响，主要体现在物种多样性十分显著地下降，群落组成和结构发生巨大变化，污染土壤和土壤群落的优势类群和优势种不同。根据研究结果，腐生波豆虫（Bodo putrinus)和梅氏扁豆虫（Phacodinium metchnico ffi)可作为铅锌类污染土壤环境的指示种类。     

Heterochromatin characterization and distribution in the chromosomes of two populations ofIdotea baltica basteri Audouin, 1826 (Isopoda,Valvifera)

Two mediterranean populations ofIdotea baltica basteri from Messina and Naples showed a set of chromosomes composed by 58 all-biarmed chromosomes. The heterochromatin was located in the pericentromeric region of the chromosomes, and its composition appeared heterogeneous. In fact, not all the homologs showed heterochromatin resistant to digestion with three restriction enzymes (Alu I, Hae III and Sau 3A). Moreover, the two populations showed polymorphism in a band of G+C-rich telomeric heterochromatin, which was present only in the population from Messina. It is hypothesized that chromosomal polymorphism might reflect the geographical isolation of the two populations. It is also suggested that a process of diversification is taking place.     

The margin of overgrowth of the embryonic chick blastoderm as a study model for cell-to-cell contacts

Zusammenfassung Die Entwicklung vom «margin of overgrowth» junger Hühnerkeime ist verschieden nach Kontakt mit Helazellen und mit Mesonephros oder Hautgewebe; die ersteren hemmen die Entwicklung, die anderen werden vom Keim aufgenommen. Deshalb wird der «margin of overgrowth» als Modell für die Studie von Zellkontakten vorgeschlagen.