Factors Influencing the Efficacy of the Potential Microbial Herbicide Alternaria alternata (Fr.) Keissler on Amaranthus retroflexus (L.)

Alternaria alternata , applied to run-off at 107 conidia ml -1 and given a 6 h dew period, caused an 88.5% reduction in dry weight of 4 to 5 true-leaf plants of Amaranthus retroflexus . This level of control was achieved whether the inoculated plants were grown in the glasshouse or outside. Formulation of the pathogen in oilseed rape emulsion reduced its dew period requirement from 24 h or more to 8 h or less. For example, with 106 conidia ml -1 , equivalent effects were found with 8 h dew with emulsion formulation compared to 48 h dew with the Tween formulation. Allowing spray deposits to dry on inoculated plants for ca 7 h, before exposing to dew increased the efficacy of the pathogen.     

Resource allocation and time budgeting in adults of the cockroach,Periplaneta americana: The interaction of behaviour and metabolic reserves

Activity (to food, water and shelter) and resource allocation (mass budget, and size of various body components) were examined in populations of adult Periplaneta americana subjected to periods of starvation or sugar feeding. Following 13 days of starvation, roaches ate 5 times their normal daily ration and feeding required about 20 days to return to pre-starvation levels. When sucrose was substituted for the usual dog-food diet for 13 days, there was also a large increase in feeding initially. When the dog food was re-established, however, there was very little feeding for about one week. Although reproduction was markedly curtailed by starvation, females fed sucrose continued reproducing for at least 59 days. The results suggested that the roaches were mainly energy limited. Although the consumption of roaches was strongly affected by reserve depletion, eating was a small component of the time budget, and overall activity was relatively unchanged by starvation or sugar-feeding. There was a slight decrease in activity during starvation, but the circadian pattern remained unchanged. Females carrying oöthecae were highly active and were apparently attracted to food (even though they ate little). Thus the activity of the population was dominated by circadian rhythmicity and the reproductive cycle.     

Reproductive strategy of insects as adaptation to temporally varying environments

Diversity of oviposition curve observed in 125 insects was analysed using the ratio of the length of period for development to that for reproduction. On the basis of this empirical data, two extreme reproductive patterns were selected: prolonged reproduction with early maturity and concentrated reproduction with late maturity. Population growth of the species with each reproductive pattern was calculated usingLeslie Matrix under some simulated fluctuating environments where the length of time during which the environments change is short compared with the time required to stabilize age structure. These simulation studies show that there is an optimal ratio of the length of period for development to that for reproduction in achieving high population densities and this ratio varies depending on the favorableness of environment for reproductive success: as the environmental favorableness decreases, the optimal ratio becomes larger.     

自适应干扰对消技术提取胎儿心电的可视化仿真实现

目的：用可视化编程技术实现胎儿心电信号提取和分析。方法：获取受试者仰卧位的腹部平行放置的两对电极的二道心电信号;在Windows系统下,用Delphi嵌入汇编技术实现对模/数采样卡的低层I/O操作;用自适应干扰对消技术提取胎儿心电信号。结果和结论：计算机仿真结果表明,该方法的能获取较清晰的胎儿心电信号。讨论：①基于Windows开发的系统具有较好的交互性和移植性,②获得胎儿心电后可用我们巳开发的成熟技术实现对胎儿心动周期信号的混沌特征分析,以估计胎儿自主神经系统功能。     

福建历史时期人骨的种族特征

本文对福建东山岛出土的明末清初的墓葬人骨进行观测。通过与其周边地区人群的比较,讨论了闽台两地居民的关系。结果表明东山组与高山族、福建近代组的关系最密切,均源于我国南部地区的较早的智人。     

Impact of developmental variance on behavior of models for insect populations I. Models for populations with unrestricted growth

The concept of developmental variance is discussed with reference to its use in models for insect populations. When included in a model, developmental variance is typically used to describe the variation of developmental periods among individuals. However, its presence in a model can also have indirect impact on survival and fertility schedules. This impact can lead to significant changes in population growth rates and generation times. These relationships between developmental variance and population growth in models are quantified and discussed.     

Helminths: comparison of their rhodoquinone

A rhodoquinone (RQ) has been isolated from Stephanurus dentatus and has been shown to be identical with RQ-9 from Ascaris lumbricoides var. suis (A. suum). The ratio of RQ/mg N is fairly constant among larval, juvenile, and adult forms of S. dentatus with an average value of 1.63 μg/mg N. A Chromatographie survey found RQ in all eleven species of helminths tested. Ubiquinone (UQ) was found in all larval forms, a free living nematode (Rhabditis strongyloides) and helminths with prepatent periods shorter than 35 days.     

风险预判与主动干预在综合ICU患者多重耐药菌医院感染防控中的关键作用研究

目的:阐述风险预判与主动干预的综合防控措施对综合重症监护病房(GICU)患者多重耐药菌(MDRO)医院感染的防控效果。方法:对2018年1月~2019年12月入住GICU病房(分为A、B两个病区)>48 h的737例患者进行回顾性调查,其中A病区监测患者286例,MDRO防控参照院感科常规制度要求;B病区监测患者451例,MDRO防控采用入GICU时预判患者感染风险,再根据感染风险及患者自身状况对患者采取鼻腔去定植或肠道去定植的综合防控策略。用卡方检验比较两病区患者的感染结果与MDRO感染菌种分布情况,以验证不同防控策略的效果。结果:本研究共监测GICU住院患者737例,研究期间共发生MDRO医院感染85例。其中A病区监测患者286例,MDRO医院感染66例,感染率为23.1%;B病区监测患者451例,MDRO医院感染19例,感染率为4.2%,低于A病区(P<0.001)。单菌种感染结果显示,两病区感染菌种分布存在差异,CR-AB、CR-PA和MASR的感染率都为B病区低于A病区,两病区患者的共患病类型无差异。说明B病区MDRO防控效果优于A病区。结论:感染风险预判与主动干预的综合防控策略,有利于降低GICU患者MDRO医院感染发病率。     

Changes in circadian rhythms during puberty in Rattus norvegicus: developmental time course and gonadal dependency

During puberty, humans develop a later chronotype, exhibiting a phase-delayed daily rest/activity rhythm. The purpose of this study was to determine: 1) whether similar changes in chronotype occur during puberty in a laboratory rodent species, 2) whether these changes are due to pubertal hormones affecting the circadian timekeeping system. We tracked the phasing and distribution of wheel-running activity rhythms during post-weaning development in rats that were gonadectomized before puberty or left intact. We found that intact peripubertal rats had activity rhythms that were phase-delayed relative to adults. Young rats also exhibited a bimodal nocturnal activity distribution. As puberty progressed, bimodality diminished and late-night activity phase-advanced until it consolidated with early-night activity. By late puberty, intact rats showed a strong, unimodal rhythm that peaked at the beginning of the night. These pubertal changes in circadian phase were more pronounced in males than females. Increases in gonadal hormones during puberty partially accounted for these changes, as rats that were gonadectomized before puberty demonstrated smaller phase changes than intact rats and maintained ultradian rhythms into adulthood. We investigated the role of photic entrainment by comparing circadian development under constant and entrained conditions. We found that the period (τ) of free-running rhythms developed sex differences during puberty. These changes in τ did not account for pubertal changes in entrained circadian phase, as the consolidation of activity at the beginning of the subjective night persisted under constant conditions in both sexes. We conclude that the circadian system continues to develop in a hormone-sensitive manner during puberty.