Hybridization experiments: evidence of dissociation equilibrium in hemerythrin

Partial succinylation of hemerythrin alters its electrophoretic mobility even though it remains an octameric macromolecule. Mixtures of this modified protein and unmodified hemerythrin generate species of intermediate electrophoretic mobility. Such behavior provides strong evidence that the octameric macromolecule is in mobile equilibrium with monomeric subunits.     

A permian productoid brachiopod: life history

Spine arrangements on silicified specimens of Waagenoconcha abichi (Waagen) from the Khisor Range of West Pakistan suggest that the juvenile shell attached itself to a foreign object, and that the adult shell lay on its ventral valve in the substrate, anchored and stabilized by a dense corona of long slender spines around the ventral visceral disc.     

End-cretaceous brachiopod extinctions in the chalk of denmark

The results of a detailed study of the brachiopods of the most complete Cretaceous-Tertiary boundary in Denmark, Nye Klslashed circlev, show an extinction pattern for this marine invertebrate group compatible with that reported for pelagic foraminifera and coccoliths and with the impact scenario. The extinction is abrupt, coinciding with the Maastrichtian-Danian boundary. There is no warning in the form of decreasing density, decreasing diversity, or early extinction of specialized groups. The basal few meters of the Danian are almost devoid of brachiopods, and a Danian brachiopod fauna starts almost as abruptly as the Maastrichtian fauna disappeared. The new fauna is similar to the Maastrichtian as regards density and diversity, and at maximum six species are common to both stages. The northwest European Masstrichtian chalk is composed mainly of the remains of coccoliths and pelagic foraminifera. The mass extinction of these groups led to a total cessation of chalk production. The chalk is overlain by a thin clay bed deposited partly under anoxic conditions. This combination of anoxia and clay deposition coupled with a cessation of productivity led to the extinction of specialized groups such as the chalk brachiopods. The surviving species included forms that could survive in well-aerated shallow marine waters on substrates other than chalk.     

白条锦蛇耗氧量和耗氧率

测定了5种温度(14 、17、 20、 24和29℃)下,白条锦蛇的耗氧量及耗氧率.结果表明:在这5种温度条件下,白条锦蛇的耗氧量均随体质量的增加而明显增大,而白条锦蛇的耗氧率则刚好相反,随体质量的增加耗氧率反而减小; 另外,白条锦蛇的耗氧量、耗氧率与温度均呈显著的线性回归关系.在14～29℃白条锦蛇的耗氧量、耗氧率均随温度升高而增加,并得出耗氧量x0与温度t的一元线性回归方程:x0=-25.25+3.51t,耗氧率Q0与温度t的一元线性回归方程Q0=-230.25+27.14t.白条锦蛇的耗氧率与温度的变化关系,说明白条锦蛇的新陈代谢率随环境温度改变而改变,在14～29℃白条锦蛇的新陈代谢随环境温度升高而加快.     

黄花梨的动态特性试验研究

动态特性是评价水果质地和成熟程度的的一个重要指标。利用正弦曲线应力-应变动态试验测定了黄花梨的动态特性，发现在不同预加载荷、不同激振功率、不同成熟程度等条件下梨果实动态试验的弹性模量和相位角明显不同。这表明：在相同频率下，随预加载荷的增加，弹性模量值增加；在相同预载荷、激振功率和频率下，未成熟黄花梨的动态试验相位角较小、成熟黄花梨的相位角较大，未成熟黄花梨的动态试验弹性模量较大，成熟黄花梨的弹性模量较小     

超级稻平衡施肥效应研究

为建立超级稻施肥模型,应用＂3414＂设计方案在苍梧县对超级稻Y两优1号进行田间肥效试验,研究不同配方施肥对其产量的影响。结果表明,氮、磷、钾配施有显著的增产效果;在一定范围内,氮、磷、钾肥的施用量对超级稻的增产作用是氮肥大于钾肥,钾肥大于磷肥。     

复等位基因平衡群体熵的性质

研究了复等位基因平衡群体熵的性质 ,并与基因多样度 D、相对信息多样度 S′(A)、相对纯合度信息多样度 S′ J(A)、相对杂合度信息多样度 S′ H(A)及多态信息含量 PIC进行了比较研究。结果表明 ,在表征基因变异与遗传变异上 ,信息论方法与统计学方法具有一致性 ,而且信息论方法还具有信息学含义     

茶叶吸湿解吸平衡规律的分析

为探讨茶叶的吸湿解吸平衡规律,分析了不同茶叶品种在茶叶吸湿解吸平衡过程中含水率的变化趋势。采用静态重量法测定35℃下、水活度为0.06～0.90时3种红茶和3种绿茶的吸湿解吸平衡含水率,并对试验数据进行模型拟合,绘制出其水分吸湿解吸等温曲线。测定结果表明,不同茶叶品种的水分吸湿解吸等温曲线呈现的形状极似S型,解吸平衡含水率高于吸湿平衡含水率,表现出滞后现象。应用SPSS软件对红茶和绿茶的试验结果进行单因素方差分析,结果表明茶叶品种对其吸湿解吸平衡含水率的影响不显著。