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161.
A commonly used measure of ordinal association in two-way contingency tables is Goodman and Kruskal's gamma. In a randomized clinical trial setting, the row variable may consist of increasing doses of a drug and placebo (i.e., treatments) and the column variable may be an ordinal response variable (e.g., physician's global evaluation of treatment effectiveness). Typically, patients are randomly assigned to treatments (rows) such that the row totals are fixed and the rows form a product-multinomial sample of the ordinal response variable. For the above situation, we provide the asymptotic variance of gamma using the delta method. The population version of gamma and its standard error can be estimated by their sample counterparts, enabling us to construct approximate tests and confidence intervals using the normal distribution. 相似文献
162.
163.
Genetically manipulated Brassica genotypes affect demography and performance of Diadegma semiclausum parasitizing Plutella xylostella
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M. Nikooei Y. Fathipour M. Jalali Javaran M. Soufbaf 《Journal of Applied Entomology》2017,141(3):161-171
The performance of Diadegma semiclausum (Hellen) (Hymenoptera: Ichneumonidae) on Plutella xylostella (L.) (Lepidoptera: Plutellidae) reared on canola's progenitor (Brassica rapa L.), two cultivated canola cultivars (Opera and RGS003), one hybrid (Hyula401), one gamma‐ray mutant‐RGS003 and one transgenic (PF) genotype was compared using the age‐stage, two‐sex life table parameters. All experiments were carried out in a growth chamber at 25 ± 1°C, 65 ± 5% RH and a photoperiod of 16 : 8 (L : D) h. There were significant differences in duration of different life stages of D. semiclausum on its host larvae reared on different plant genotypes. The shortest (12.27 days) and longest (15.21 days) pre‐adult developmental times were observed on cultivar‐RGS003 and hybrid‐Hyula401, respectively. The intrinsic rate of increase (r) in D. semiclausum ranged between 0.189/day (cultivar‐Opera) and 0.141/day (transgenic‐PF). Moreover, the highest (20.078 offspring) and lowest (12.027 offspring) net reproductive rates (R0) were observed on cultivar‐Opera and hybrid‐Hyula401. The mean generation time (T) of D. semiclausum was the highest (18.34 days) and lowest (15.05 days) on mutant‐RGS003 and cultivar‐RGS003. The maximum and minimum parasitism values of this parasitoid were observed on canola's progenitor (44.28%) and hybrid‐Hyula401 (37.09%). The heaviest pupae (3.82 mg) and females (3.22 mg) of the parasitoid were found on canola's progenitor and cultivar‐Opera, respectively. The results showed that performance of this parasitoid was better on canola's progenitor and cultivated plants known to have higher levels of glucosinolates concentration than others. 相似文献
164.
Host plants mixture and fitness of Kolla paulula: with an evaluation of the application of Weibull function
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S.‐J. Tuan P.‐W. Chang P. Saska R. Atlihan H. Chi 《Journal of Applied Entomology》2017,141(5):329-338
The xylem‐feeding leafhopper Kolla paulula (Walker), a vector of Pierce's disease, occurs primarily on weeds in and around fruit and ornamental crop orchards in Taiwan. Because our preliminary studies showed that K. paulula performed poorly when reared on pilose beggarticks (Bidens pilosa L. var. radiata) (PB) or trilobate wedelia (Wedelia triloba (L.)) (TW) alone, we collected the life table data of K. paulula reared on a mixture of both host plants to determine the effect at the population level. During their lifespan, 95.6% of feeding time was spent on the major host plant (PB) and only 4.4% on the minor host plant (TW). The intrinsic rate of increase (r), finite rate of increase (λ), net reproduction rate (R0) and mean generation time (T) of K. paulula were 0.0487, 1.0500 day?1, 35.86 offspring and 73.4 days, respectively. Because more than 95% of the insects have been observed feeding on both plants, this would indicate that the minor host plant may play an important role in the fitness of K. paulula regardless of the short feeding time. We calculated the percentage contribution to the population parameters made by females that had fed on both PB and TW and compared these with the values obtained for offspring of females that had fed solely on PB. We also evaluated the usefulness of applying the Weibull distribution in demographic studies. We demonstrated that when there is a higher mortality in specific life stages, the fitted Weibull distribution would be inaccurate in describing the survival curve and that application of the fitted curve to the calculation of life expectancy or other statistics would result in significant discrepancy to the actual curve. 相似文献
165.
磷酸化是蛋白质翻译后的主要修饰,可分为激酶特异性和非激酶特异性两种类型.以非激酶特异性磷酸化位点Dou数据集为基础,本文发展了一种基于位置的卡方差表特征χ2-pos,融合伪氨基酸序列进化信息PsePSSM表征序列,构建正负样本均衡的支持向量机分类器,S, T, Y独立测试Matthew相关系数、ROC曲线下面积分及准确率分别达到了(0.59、0.87、79.74%),(0.55、0.85、77.68%)和(0.50、0.81、75.22%),明显优于文献报道结果. χ2-pos、PsePSSM两种特征的融合在蛋白质磷酸化位点预测中有广泛应用前景. 相似文献
166.
郭飙 《中国应用生理学杂志》2016,32(2):170-172
目的:探讨长期乒乓球运动对老年人身体健康的影响,以期为当前严重老龄化的社会背景下为老年群体提供一种简易、有效且易养成运动习惯的体育锻炼方式。方法:选取30名长期从事乒乓球运动的老年人为运动组,另选取30名无体育运动习惯的老年人作为对照组,通过相关仪器测试对运动组及对照组身体形态、身体素质及机能指标进行测试、分析。结果:运动组老年人身体形态、身体素质及身体机能状态等指标明显好于对照组;其中身体形态指标以皮脂变化最为明显(P<0.05)、身体素质指标以反应时、握力变化最为明显(P<0.05)、身体机能状态指标以骨密度、血压、肺活量变化最为明显(P<0.05)。结论:长期从事乒乓球运动可明显改善老年人身体形态、身体素质及身体机能状态,对提高老人身体健康有着重要的意义。 相似文献
167.
【目的】 研究阐明不同光周期条件下棉花粉蚧Phenacoccus solenopsis Tinsley实验种群的发育历期、繁殖和数量动态规律,为制定该虫防治对策、研究治理措施等提供科学依据。【方法】 以扶桑为寄主,在温度27±1℃、相对湿度70%±5%、光照强度4 000 lx及不同光周期(8L∶16D, 10L∶14D, 12L∶12D, 14L∶10D和16L∶8D)条件下,观察了棉花粉蚧实验种群的生长发育特性和繁殖能力,组建了实验种群生命表。【结果】 不同光周期处理下棉花粉蚧1龄若虫和3龄若虫的发育历期及雌成虫产仔量均发生了变化,但不同龄期若虫存活率之间差异不大。随着光照时间增加,棉花粉蚧1龄若虫、3龄若虫发育速率加快,8 h光照时发育历期分别为5.43 d和6.35 d,而16 h光照时发育历期分别缩短至4.16 d和4.75 d;整个若虫发育历期也由8 h光照时的15.54 d缩短至16 h光照时的12.74 d,世代历期由27.75 d缩短至23.45 d。长光照时雌虫更早进入产仔期,也有利于雌虫繁殖后代,16 h光照时进入产仔期是18日龄,8 和10 h光照时均推迟至22日龄;16 h光照时单雌产仔量为417.06头,明显高于12 ,10 和8 h光照时的353.59,347.61和336.00头。长光照条件下实验种群趋势指数(I)明显较大,增长潜能更大,16,10 和8 h光照时种群趋势指数分别为 175.37,133.94和141.99。该虫生命表参数表明,随着光照时间加长净增值率(R0)呈逐渐增大趋势,8, 10,12,14和16 h光照时分别为88.57,86.85,100.77,124.16和126.86;内禀增长率、周限增长率表现类似的规律,8~16 h光照时内禀增长率(rm)为0.1616~0.2066,周限增长率(λ)为1.1754~1.2294;而种群倍增时间(t)则随着光照时加长而缩短,8~16 h光照时为4.29~3.36 d。【结论】 长光照有利于棉花粉蚧生长发育和繁殖,世代历期缩短,种群增长潜能变强。 相似文献
168.
温度对桃蚜和马铃薯长管蚜实验种群生命表参数的影响 总被引:1,自引:0,他引:1
【目的】桃蚜Myzus persicae (Sulzer)和马铃薯长管蚜Macrosiphum euphorbiae (Thomas)是2种主要的马铃薯害虫。本研究旨在明确温度对这两种马铃薯蚜虫生长发育、存活、繁殖及种群增长的影响。【方法】在室内测定了5个温度(10, 15, 20, 25和30℃)下桃蚜和马铃薯长管蚜的生长发育、存活和繁殖指标,并组建了4个恒温条件下(10,15,20和25℃)的实验种群生命表。【结果】在10~25℃范围内,2种蚜虫的若蚜期、世代历期、成蚜寿命和产蚜期等均随温度的升高而缩短,而30℃高温抑制了其发育、存活和繁殖。2种蚜虫的平均世代历期(T)随温度的升高而缩短,桃蚜和马铃薯长管蚜分别从10℃的30.08 d和35.35 d缩短至25℃的14.28 d和12.95 d。桃蚜的净增殖率(R0)在15℃时最高(86.00),其次为20℃(73.75),再次为25℃(62.49),最低为10℃(51.00);马铃薯长管蚜的R0在15℃最高(58.97),其次为10℃(51.98),再次为20℃(48.94),最低为25℃(12.36)。桃蚜的内禀增长率(rm)随温度的升高而增大,从最小10℃的0.1307增大到25℃的0.2896;马铃薯长管蚜的rm在20℃时最大(0.2182),其次为25℃(0.1942),再次为15℃(0.1485),最小为10℃(0.1118)。在相同的温度下,桃蚜的发育速率、净增殖率和内禀增长率均高于马铃薯长管蚜。【结论】温度对2种马铃薯蚜虫的生长发育、存活、繁殖及种群增长有显著的影响,桃蚜在马铃薯上的种群增长能力强于马铃薯长管蚜。这一结果为马铃薯蚜虫预测模型的建立奠定了必要的基础,并解释了桃蚜在马铃薯上发生数量多于马铃薯长管蚜的原因。 相似文献
169.
Preimaginal development and adult longevity and reproduction of Dichochrysa prasina Burmeister were studied at six constant temperatures (15, 20, 25, 27, 30 and 33 °C) and a photoperiod of 16:8 (L:D). Eggs of the flour moth Ephestia kuehniella (Zeller) were used as food throughout preimaginal development, whereas the adults of D. prasina fed on a liquid diet of water, yeast hydrolysate, sugar and honey. At the highest tested temperature of 33 °C no larvae completed their development. At the rest of the tested temperatures the egg to adult developmental period ranged from approximately 92 days at 15 °C to 25 days at 30 °C. Percentages of adult emergence ranged from 36% at 15 °C to 84% at 30 °C. Both adult longevity and fecundity were significantly affected by temperature and the intrinsic rate of increase (rm) reached its maximum value at 27 °C. These results could be useful for the establishment of a small scale rearing and mass production of D. prasina. 相似文献
170.
The effect of five constant relative humidity (RH) regimes (12%, 33%, 55%, 75% and 94%) on the preimaginal development and adult longevity and reproduction of Dichochrysa prasina Burmeister was studied at 26 ± 1 °C and a photoperiod of 16:8 (L:D) under laboratory conditions. For the experiments, larvae were fed individually on eggs of the flour moth Ephestia kuehniella (Zeller), whereas adults on a liquid diet consisting of water, yeast hydrolysate, sugar and honey. The experimental insects were maintained individually in sealed plastic containers with saturated water salt solutions at the base to control RH. Preimaginal developmental time from egg to adult for females and males was significantly shorter at 75% and 94% RHs than at other RHs in the range from 12% to 55%. Percentages of adult emergence were similar at all RHs tested and varied from 52.5% to 75.0%. Adult females that had no access to water and were maintained at 12%–75% RH lived on average less than two weeks and laid no eggs, whereas at 94% RH they lived longer and each laid on average 201 eggs. When the females had periodic access to a water source a significant increase in both longevity and egg production occurred and the estimated intrinsic rate of increase was high, irrespective of RH. These results could be useful for the mass-rearing of D. prasina and for better understanding its population dynamics under field conditions. 相似文献