维生素B12对萼花臂尾轮虫种群的影响

温度为15℃时,添加20,40,80和100μg/mL维生素B12后,萼花臂尾轮虫(Brachionuscalyciflorus)种群密度随时间增加而增长,其回归方程依次为:y=e(0.1757+0.2974x),y=4.6765x1.2079,y=7.7798x1.0175和y=e(0.6117+0.3469x),密度显著高于对照组(t=4.56,8.15,8.53和9.86;P1.4366,y=7.7461x1.6533,y=6.3611x1.7790和y=9.064x1.6872,对照为y=7.5902x1.50192。各添加组的密度均显著高于对照组(t值分别为16.12,10.17,5.83和5.86;P(0.1376+0.4395x),y=e(0.2032+0.4856x),y=3.4615x1.9522和y=e(0.0220+0.48074x)。对照组除了和20ng/mL组间没有统计差异外(t=0.34,P>0.05),其他各实验组密度显著高出对照组(t值分别为3.66,10.23和2.13)。最高混交率分别为18.18%,7.60%,18.18%和16.67%,对照为66.70%。最大卵雌比依次为0.70,1.90,0.91,1.09,对照组为0.95。       

桔小实蝇在番石榴上的防治指标研究

番石榴是桔小实蝇Bactrocera dorsalis(Hendel)主要寄主之一,受桔小实蝇为害严重,经济损失大。为指导番石榴园桔小实蝇的防治,本文在建立番石榴被害率(y)、产量损失率(y)与桔小实蝇雄虫数量(x)的回归方程基础上,提出了番石榴园桔小实蝇的防治指标。夏果期和秋果期番石榴被害率(y)与桔小实蝇雄虫诱集数量(x)间回归方程分别为:y=0.680x+1.951和y=0.736x+0.535;产量损失率(y)与雄虫诱集数量(x)之间的回归方程:y=0.697x+2.457和y=0.730x+1.831;产量损失率(y)与番石榴被害率(x)的回归方程:y=1.115x+0.638和y=0.998x+1.756。提出的番石榴上桔小实蝇的防治指标如下:(1)以性诱剂诱集的雄虫数量为标准,对于采取喷药结合性诱剂防治的果园,夏果期和秋果期桔小实蝇防治指标分别为0.97头/瓶/4 d和2.97头/瓶/4 d;对于采取套袋防治措施的果园,夏果期和秋果期桔小实蝇防治指标分别为4.75头/瓶/4 d和5.01头/瓶/4 d;(2)以番石榴被害率为标准,对于采取套袋防治措施的果园,夏果期和秋果期防治指标分别为5.18%和4.22%;对于采取喷药结合性诱剂防治的果园,防治指标分别为2.61%和2.72%。     

一类KOLMOGOROV系统的极限环

关于两种群互相作用的Kolmogorov模型 x=xF_1(x,y), y=yF_2(x,y),文〔1〕根据生态意义对F_1、F_2给出较多限制条件下作过研究,由于现实中总结出的模型归结到F_1、F_2为x和y的多项式的形式不少〔2,3〕,本文讨论一类Kolmogorov系统x=x(a_0+a_1x-a_3x~2+a_2y+a_4xy),y=y(x-1) (1)极限环的存在性和唯一性,其中x和y分别表示两种群的密度,参数a_0>o,a_3>o,a_1、a_2、a_4不定号,它们各表示一定的生态意义,随不同的取值范围而反映两种群的不同作用〔1〕。     

一类稀疏效应下的捕食系统存在唯一极限环的充要条件

给出了如下一类稀疏效应下的捕食系统：x=bx^2k-x)-bxy,y=-cy (βx-γy)y存在唯一极限环的充要条件。     

功能反应函数为x~(1/2)的食饵-捕食系统的定性分析

本文运用Liapunov第二方法,论证了功能反应函数为x～(1/x)的食饵-捕食系统x=x-ax-2~3-x~(1/x)y,βy=-sy βx~(1/x)y-εy~2唯一正平衡点的稳定性．其次将该系统化为二次微分系统Ⅲ类方程的标准形式,进而研究了极限环的存在唯一性问题．     

珍稀濒危保护植物蒙古扁桃的生长特性研究

通过连续9 a定株观测方法,研究了蒙古扁桃物候期对应气候因子指标、年株高变化、地径生长、冠幅变化及根系变化规律,结果表明:物候期与气温、地表温度、地温(15 cm)、空气湿度和水汽压等因子关系密切,而与蒸腾量和日照时数关系较疏;年株高变化符合直线方程:y=18.91 8x-0.780 6(R2=0.991 5);年地径变化符合直线方程:y=0.275 6x 0.348 6(R2=0.999 2);年冠幅变化符合指数方程:y=50.371e0.2527x(R2=0.989 9);根系纵向和横向生长趋势分别符合指数函数方程:y=12.914e0.7358x(R2=0.971 5)和y=17.126e0.6918x(R2=0.965 4),但纵向生长落后于横向生长,即侧根生长优于主根。     

一类具功能反应的食饵-捕食者两种群模型的定性分析

对具功能反应的食饵-捕食者两种群模型x=xg(x)-y( )(x),y=y(-d+e( )(x)).在g(x)=α-baα,( )(x)=cxα(a,b,c＞0,1/2≤α＜1)且α使函数f(x)=x1/a在(-∞,+∞)上为偶函数时进行了研究,讨论了该系统平衡点的稳定性态,系统无环的充分条件以及在正平衡点外围存在惟一稳定极限环的条件.     

松树内含物与松墨天牛种群数量的关系

对不同林分松墨天牛种群密度进行解剖调查,黑松为32.63头/株,马尾松为16.69头/株,湿地松为12.44头/株,黑松与湿地松之间差异显著;对黑松、马尾松、湿地松枝条及韧皮部中蛋白质、可溶性糖、水分、N、P、K、S、Cl、Ca、Mg、Cu、Zn、Fe、Mn、16种游离氨基酸和16种水解氨基酸进行测定,并与黑松、马尾松、湿地松上的松墨天牛种群数量(y)之间关系进行数学分析。蛋白质(x1)、可溶性糖(x2)与y的关系为y=-44.07-1.5601x1+6.9355x2,复相关系数为0.8374*;游离氨基酸与y的关系为y=63.24-1.1775x5-0.0680x11+0.1665x12-0.1257x15,复相关系数为0.9999**。x5为甘氨酸、x11为酪氨酸、x12为苯丙氨酸、x15为脯氨酸;水解氨基酸与y的关系为y=37.59-0.1146x10-0.5741x11+0.0112x15+0.1468x16,复相关系数R为0.9955**,x11为酪氨酸、x15为脯氨酸、x16为精氨酸、x10为亮氨酸;矿质元素与y的关系为y=-67.94+409.4696x3+37.4746x6-1004.4480x7+4.2958x8,复相关系数R为0.9826*,x3为K、x6为Ca、x7为Mg、x8为Cu。综合分析14种入选的内含物与y的关系为y=19.94+0.0114x2+0.0457x4-0.5317x5+62.5214x9,复相关系数R为0.9966**,x2为水解酪氨酸、x4为水解脯氨酸、x5为游离酪氨酸、x9为K,综合分析表明水解和游离的酪氨酸、水解脯氨酸和K的含量对松墨天牛种群有重要影响。     

一类含单奇点的极限环的三次系统

证明具体三次系统x=y-εy~3,y=x(1-x~2)+(α-x~2)y,当α≥1或0<α≤1/3时,在区域|y|<1/ε~(1/2)内无含单奇点的极限环,这里ε>0.     

一类稀疏效应下捕食—被捕食系统极限环的唯一性

捕食与被捕食种群增长可以Lotka-Votterra模型x=ax(1-kx)-bxy y=y(-a+βx)描述,其中a,k,b,a,β皆为非负常数,其生物意义见[1],但是人们在长期的研究     

再论一类酶促反应化学动力系统

研究文[2]所讨论过的关于C.S.T.R反应器的一类两分子饱和反应模型x=-k1xy+q(x0+x),y=k1xy-kzy/1+ry-qy,并给出了一些具有指导实践意义的信息.     

一种新的分子遗传相似度计算方法

指出了Nei氏遗传相似度仅仅是用来描述两个二进制变量差异相似程度程度的一种距离系数或相似系数,与个体间亲缘程度没有必然联系。根据亲缘系数的定义,提出新的遗传相传相似计算公式即rA(x,y)=2N^2xy/NxNy或rA(x,y)=N^2/NxNy。并通过实例验证了该公式可用于判断个体间亲缘程度方面。     

On Liénard's equation and the uniqueness of limit cycles in predator-prey systems

We study a system of ODE's modelling the interaction of one predator and one prey dx/dt = xg(x) - yp(x), dy/dt = gamma y[- delta - nu y - alpha y2 + h(x)]. This system defines a two-species community which incorporates competition among prey in the absence of any predators as well as a density-dependent predator specific death rate. This system is investigated under ecologically natural regularity conditions and assumptions on g, p and h to ensure the existence and uniqueness of limit cycles. The proof uses the standard Hopf-Andronov bifurcation theory and the technique of Liénard's equation.     

黑线仓鼠种群数量动态预测研究

１９８４－１９９１年３－１０月,每月中旬在中国农科院草原研究所试验场的不同牧草和作物地进行调查,１９８４－１９９１年共捕获鼠４０９３只,其中黑线仓鼠２９２０只占７１．３４％。黑线仓鼠种群数量季节和年度变化明显,利用电子计算机对黑线仓鼠种数量进行分析,提出种群数量繁殖指数和动态模型以及短、中、长期预测公式、预测准确率为９０．０％。并对影响种群数量的因素进行了初步分析。     

Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry

The purpose of this study was to quantify the decrease in the load lifted from 1 to 5, 10, and 20 repetitions to failure for the flat barbell bench press (chest press; CP) and plate-loaded leg press (LP). Furthermore, we developed prediction equations for 1 repetition maximum (RM) strength from the multiple RM tests, including anthropometric data, gender, age, and resistance training volume. Seventy subjects (34 men, 36 women), 18-69 years of age, completed 1, 5, 10, and 20RM testing for each of the CPs and LPs. Regression analyses of mean data revealed a nonlinear decrease in load with increasing repetition number (CP: linear S(y.x) = 2.6 kg, nonlinear S(y.x) = 0.2 kg; LP: linear S(y.x) = 11.0 kg, nonlinear S(y.x) = 2.6 kg, respectively). Multiple regression analyses revealed that the 5RM data produced the greatest prediction accuracy, with R(2) data for 5, 10, and 20RM conditions being LP: 0.974, 0.933, 0.915; CP: 0.993, 0.976, and 0.955, respectively. The regression prediction equations for 1RM strength from 5RM data were LP: 1RM = 1.0970 x (5RM weight [kg]) + 14.2546, S(y.x) = 16.16 kg, R(2) = 0.974; CP: 1RM = 1.1307 x (5RM weight) + 0.6999, S(y.x) = 2.98 kg, R(2) = 0.993. Dynamic muscular strength (1RM) can be accurately estimated from multiple repetition testing. Data reveal that no more than 10 repetitions should be used in linear equations to estimate 1RM for the LP and CP actions.     

一类可逆多分子饱和生化反应系统的非线性分析

研究生化反应中一类可逆多分子饱和反应系统x=a-xy^n cy^n 1,y=xy^n-cy^n 1-dy／(y 6),应用微分方程定性理论,完整的解决了该系统极限环的存在性、不存在性和唯一性问题。     

Seasonal changes in thermoregulation of the raccoon dog (Nyctereutes procyonoides Gray 1834)

Oxygen consumption (ml X kg-0.75/min) in relation to ambient temperature (Ta) in the raccoon dog whelps at the ages of 7-9 weeks and 17-19 weeks is described by equations y = 32.9-0.69x and y = 26.2-0.49x, respectively. The corresponding equations to adults in summer and winter pelages are y = 19.6-0.46x and y = 14.5-0.32x, respectively. The cooling constant (min-1) of deceased raccoon dogs decreased exponentially with increasing body mass, while M-0.75 specific heat transfer coefficient (W X kg-0.75/degrees C) regressed linearly on body mass, y = 0.124-0.00066x. Cooling rate of deceased animals were more dependent on body mass than on pelage quality.     

Doppler echo evaluation of pulmonary venous-left atrial pressure gradients: human and numerical model studies

The simplified Bernoulli equation relates fluid convective energy derived from flow velocities to a pressure gradient and is commonly used in clinical echocardiography to determine pressure differences across stenotic orifices. Its application to pulmonary venous flow has not been described in humans. Twelve patients undergoing cardiac surgery had simultaneous high-fidelity pulmonary venous and left atrial pressure measurements and pulmonary venous pulsed Doppler echocardiography performed. Convective gradients for the systolic (S), diastolic (D), and atrial reversal (AR) phases of pulmonary venous flow were determined using the simplified Bernoulli equation and correlated with measured actual pressure differences. A linear relationship was observed between the convective (y) and actual (x) pressure differences for the S (y = 0.23x + 0.0074, r = 0.82) and D (y = 0.22x + 0.092, r = 0.81) waves, but not for the AR wave (y = 0. 030x + 0.13, r = 0.10). Numerical modeling resulted in similar slopes for the S (y = 0.200x - 0.127, r = 0.97), D (y = 0.247x - 0. 354, r = 0.99), and AR (y = 0.087x - 0.083, r = 0.96) waves. Consistent with numerical modeling, the convective term strongly correlates with but significantly underestimates actual gradient because of large inertial forces.