In vitro bioassay for the effect of Ajuga reptans phytoecdysteroids on Trialeurodes vaporariorum larval development

A rapid and reliable in vitro bioassay method to test the effects of synthetic and natural compounds on the development of greenhouse whitefly Trialeurodes vaporariorum Westwood (Homoptera Aleyrodidae) is described.Leaf fragments of Nicotiana glauca Graham infested with eggs of whitefly were cultured under aseptic conditions on half-strength Murashige-Skoog medium. The development of the insect in vitro and in vivo were comparable except for a higher mortality rate in the first larval instar.Ecdysteroids from Ajuga reptans L. were applied to leaf fragments by immersion in aqueous solution of the compounds or by addition to the culture medium. A high mortality rate of first larval instars was detected with 29-norsengosterone and ajugalactone treatments. This effect was specially pronounced when the products were incorporated in the medium. A significant increase in mortality was also recorded in the pupal state with a 20-hydroxyecdysone treatment. This effect was never observed before, because all whitefly larvae on A. reptans leaves die in the first larval instar.     

高温胁迫及其持续时间对棉蚜死亡和繁殖的影响

为探索高温胁迫对棉蚜的影响,室内采用叶子圆片培养基饲养棉蚜的方法,研究不同温度(32,34,36,38,40℃)、不同处理时间(1,2,4,6h)对棉蚜死亡和繁殖的影响.结果表明:棉蚜每日死亡率可用互补重对数模型较好地拟合.随着温度的升高和持续天数的延长,棉蚜累计死亡率呈上升趋势,38 ℃条件下其累计死亡率明显迅速上升.棉蚜半数致死温度随着每天高温处理时间的增加和高温持续天数的延长而降低,且第1-2天下降明显.棉蚜繁殖率随着温度的升高呈下降趋势,每天处理时间不同其繁殖率规律不同,但均是在38℃时下降最多.38℃可能是棉蚜耐高温能力的拐点.研究结果为提高棉蚜种群预测准确性、科学决策最佳化学防治时间提供依据.     

Distinctive patterns in prokaryotic community composition in response to viral lysis and flagellate grazing in freshwater microcosms

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温带森林生态系统粗死木质物动态研究——以中美两个温带天然林生态系统为例

通过对我国长白山自然保护区红松针阔混交林和美国Andrews试验林异叶铁杉林的林木死亡量、粗死木质物(CWD)贮量、分解速率和它们在生态系统养分循环等方面动态研究表明,CWD是温带天然林生态系统的重要组成部分,它们在生态系统功能方面的重要性,因森林类型的不同而不尽相同,CWD在针叶林中比针阔混交林中更为重要。CWD在生态系统养分循环中的一个重要作用,很可能在于系统遭受重大外界扰动后,起到贮藏养分,增加系统稳定性的作用。未来全球森林凋落物C贮量估测时,应该包括CWD,否则将低估全球森林凋落物C贮量2.0—16×10~(13)kg,系统相对误差达2—10％。     

Plurality of tree species responses to drought perturbation in Bornean tropical rain forest

Drought perturbation driven by the El Niño Southern Oscillation (ENSO) is a principal stochastic variable determining the dynamics of lowland rain forest in S.E. Asia. Mortality, recruitment and stem growth rates at Danum in Sabah (Malaysian Borneo) were recorded in two 4-ha plots (trees ≥ 10 cm gbh) for two periods, 1986–1996 and 1996–2001. Mortality and growth were also recorded in a sample of subplots for small trees (10 to <50 cm gbh) in two sub-periods, 1996–1999 and 1999–2001. Dynamics variables were employed to build indices of drought response for each of the 34 most abundant plot-level species (22 at the subplot level), these being interval-weighted percentage changes between periods and sub-periods. A significant yet complex effect of the strong 1997/1998 drought at the forest community level was shown by randomization procedures followed by multiple hypothesis testing. Despite a general resistance of the forest to drought, large and significant differences in short-term responses were apparent for several species. Using a diagrammatic form of stability analysis, different species showed immediate or lagged effects, high or low degrees of resilience or even oscillatory dynamics. In the context of the local topographic gradient, species’ responses define the newly termed perturbation response niche. The largest responses, particularly for recruitment and growth, were among the small trees, many of which are members of understorey taxa. The results bring with them a novel approach to understanding community dynamics: the kaleidoscopic complexity of idiosyncratic responses to stochastic perturbations suggests that plurality, rather than neutrality, of responses may be essential to understanding these tropical forests. The basis to the various responses lies with the mechanisms of tree-soil water relations which are physiologically predictable: the timing and intensity of the next drought, however, is not. To date, environmental stochasticity has been insufficiently incorporated into models of tropical forest dynamics, a step that might considerably improve the reality of theories about these globally important ecosystems.     

A qualitative model of mortality in honey bee (<Emphasis Type="Italic">Apis mellifera</Emphasis>) colonies infested with tracheal mites (<Emphasis Type="Italic">Acarapis woodi</Emphasis>)

The tracheal mite has been associated with colony deaths worldwide since the mite was first discovered in 1919. Yet controversy about its role in honey bee colony mortality has existed since that time. Other pathogens such as bacteria and viruses have been suggested as the cause of colony deaths as well as degenerative changes in individual honey bees. Using data from published work we developed a qualitative mortality model to explain colony mortality due to tracheal mite infestation in the field. Our model suggests that colonies of tracheal-mite infested honey bees, with no other pathogens present, can die out in the late winter/early spring period due to their inability to thermoregulate. An accumulation of factors conspire to cause colony death including reduced brood/bee population, loose winter clusters, reduced flight muscle function and increasing mite infestation. In essence a cascade effect results in the colony losing its cohesion and leading to its ultimate collapse.     

HRR、PLR与中重度颅脑损伤患者短期死亡的关系研究

摘要 目的：探讨血红蛋白/红细胞分布宽度比值（HRR）、血小板/淋巴细胞比值（PLR）与中重度颅脑损伤（TBI）患者短期死亡的关系。方法：回顾性收集2019年9月～2021年9月徐州医科大学附属医院收治的162例中重度TBI患者的病历资料,根据患者入院30d内生存状态分为死亡组和存活组。计算HRR和PLR,采用多因素Logistic回归分析中重度TBI患者短期死亡的影响因素,受试者工作特征（ROC）曲线分析格拉斯哥昏迷量表（GCS）评分联合HRR、PLR对中重度TBI患者短期死亡的预测价值。结果：162例中重度TBI患者入院30 d内死亡率为35.80%（58/162）。与存活组比较,死亡组HRR降低,PLR升高（P＜0.05）。多因素Logistic回归分析显示,GCS评分＜9分、瞳孔散大、脑疝和HRR降低、PLR升高为中重度TBI患者短期死亡的独立危险因素（P＜0.05）。ROC曲线分析显示,HRR、PLR联合GCS评分预测中重度TBI患者短期死亡的曲线下面积最大,为0.924。结论：HRR降低和PLR升高与中重度TBI患者短期死亡相关,可能成为中重度TBI患者短期死亡的辅助预测指标,在GCS评分基础上联合HRR、PLR能提升对中重度TBI患者短期死亡的预测价值。     

武汉地区西部食蚊鱼的生长、死亡系数及种群补充模式

基于2012年4月—2013年3月在武汉地区两样点调查的西部食蚊鱼数据,运用FAO开发的长度频率数据分析软件FiSATⅡ对西部食蚊鱼的生长、死亡系数以及种群补充模式进行了估算。西部食蚊鱼全长范围为8.30-44.86mm,其中优势全长为16-26 mm,占总数的69.17%;雌雄性别为2.63:1,与1:1存在显著性差异;鳞片观察发现仅存在0~+、1~+两个年龄组;雌雄样本全长与体重的关系式分别为W=4.686×10~(-6)L~(3.299)(R~2=0.953),W=1.008×10~(-5)L~(2.989)(R~2=0.903);von Bertalanffy生长方程各参数为:雌性样本极限全长L_∞=45.20 mm,生长系数k=0.52 a~(-1),起始生长年龄t_0=-0.47a,雄性样本极限全长L_∞=33.60 mm,生长系数k=0.53 a~(-1),起始生长年龄t_0=-0.50 a;雌性样本和雄性样本的自然死亡系数M分别为1.64 a~(-1)、1.81 a~(-1),而总死亡系数Z分别为2.29 a~(-1)、2.37 a~(-1);种群补充模式表明,每年4-9月份为西部食蚊鱼的主要补充期。西部食蚊野生种群表现出了寿命短、生长速度快、自然死亡率高、种群补充时间长等特征,表明该物种是一种典型的r对策物种。据此我们提出了针对性的防控措施:阻止其引入,尽早发现并根除该物种。     

Early life environment and adult height: The case of Chile

In this paper, we analyze the relationship between adult height and early-life disease environment, proxied by the infant mortality rate (IMR) in the first year of life, using cohort-region level data for Chile for 1960–1989. IMRs show a remarkable reduction of 100 points per thousand over this thirty-year period, declining from 119.4 to 21.0 per thousand. We also document a 0.96 cm increase in height per decade.We find that the drop in IMRs observed among our cohorts explains almost all of the long-term trend in rising adult heights, and that per capita GDP does not appear to have any predictive power in this context. Results are robust in a variety of specifications, which include area and cohort dummies, an adjustment for internal migration, and urbanization rates. Our results point to the long-term effect of a public health policy.     

急性心肌梗死伴新发束支传导阻滞的临床意义

目的:观察急性心肌梗死伴新发左、右束支传导阻滞的临床特点,评价束支阻滞对急性心肌梗死预后的影响。方法:对上海交通大学附属第一人民医院心内科重症监护室2010年1月1日到12月31日收治的197例急性心肌梗死患者的病历资料进行回顾性分析,根据束支传导阻滞有无及类型分为左束支传导阻滞组(12例),右束支传导阻滞组(19例)和对照组(无束支传导阻滞的急性心梗,166例)。分析和比较三组患者的基线资料,心梗部位、Killip分级、恶性室性心律失常、左室射血分数LVEF、病变血管数量、梗死相关冠脉、住院天数及病死率、实验室检查(BNP,心肌损伤标志物峰值)。结果:LBBB组AMI患者的恶性心律失常发生率明显高于对照组(P=0.007),LVEF明显低于RBBB组和对照组(P值分别为0.020、0.045),梗死相关动脉以LAD多见。结论:急性心梗伴束支传导阻滞往往提示病情严重,预后不良,急性心梗合并左束支阻滞较合并右束支阻滞病情更严重。