Correlation of rotifer associations in a chain of lakes fed by reclaimed sewage

The quantitative composition of the rotifer fauna of seven interconnected lakes located in southern California was studied in a preliminary investigation. The lakes are fed by reclaimed sewage, and the water quality increases rapidly from the first lake, barely able to support life, to a series of lovely lakes stocked with fish and utilized for recreation. The Shannon index of rotifer population diversity showed an appropriate increase. Up to 24 – 28 different rotifer taxa in each lake provided a rich community dominated by Brachionids, Keratella and Trichocerca. The diversity and quantity of the rotifer association then declined again in the last lake. Comparison of the lakes using the Bray and Curtis index of similarity and cluster analysis supported the picture of a lake-chain evolution, a biotic development showing a maximum curve.     

Comparison of species ordinations resulting from alternative indices of interspecific association and different numbers of included species

Summary Several measures of interspecific association are compared. Dispersion and covariance are limited in value because they respond to the commonness of the species compared. Correlation is not so limited but it responds to discrepancies in commonness among the species. The practical result of these relationships between commonness and association is that only the most common species can occupy periferal positions in a species ordination. Rare species are relegated to positions near the center not on the basis of their phytosociological pattern but simply because of their rarity. Both Cole's index of association and the tetrachoric correlation overcome the problem imposed by the relationship between ordination position and species commonness and they both produce very similar results. The effect of differing numbers of species on the ordination configuration is examined using both Pearson's correlation and Cole's index. The basic pattern of the ordination is set with the first few species when Cole's index is used, however, since rare species are given more weight in the analysis with this index, the addition of several very rare species can change the configuration of the ordination.Nomenclature of species is given in Table 1.Research supported by the Eastern Deciduous Forest Biome Project, US-IBP, funded by the National Science Foundation under Interagency Agreement AG-199, BMS69-01147 A09 with the Energy Research and Development Administration — Oak Ridge National Laboratory. Research also supported by the U.S. Energy Research and Development Administration under contract with the Union Carbide Corporation. Contribution No. 240 from the EDFB, US-IBP. Publication No. 790. Environmental Sciences Division, ORNL.     

水土保持林土壤改良效益评价研究

森林效益评价是目前林业研究的热点,也是难点问题,通过评价水土保持林土壤改良效益,对效益评价的方法和思路进行了探索。指出水土保持林土壤改良效益指标体系的总目标层为效益评价综合指数,准则层包括土壤肥力、抗蚀性能和抗冲性能３个方面,指标层由水稳性团聚体含量、有机质含量、土壤酶活性、ｐＨ值、平均重量直径、团聚度、分散率、土壤硬度和渗透系数构成。在计算效益评价综合指数时,首先要对各项指标的实测数据进行处理,     

长期不同养分投入对土壤养分和水稻生产持续性的影响

以中国科学院桃源农业生态试验站15a长期田间定位试验为研究对象,分析了不同养分投入对稻田土壤养分和水稻产量可持续性的影响.结果表明,化肥与系统内循环的有机物料循环的肥力效力和产量效应基本一致,有机物料循环更有利于土壤有机质和氮素的积累;在不同养分投入下,土壤耕层有机质和全氮均呈上升趋势,年均增长率分别为1.5%～5.8%和2.5%～9.4%;与试验前相比,不同养分投入耕层磷素变动幅度在-18.3%到30%之间,钾素养分有所亏缺,下降幅度在8.1%～22.6%之间;通过可持续性指数的分析得出,土壤N素养分的可持续性对化肥的依赖性较大,而P、K养分的可持续性则对有机肥的依赖性更高.稻田生态系统具有良好的自维持能力,系统内有机物循环有利于提高稻谷产量的稳定性和可持续性.     

非嗜食植物乙醇提取物对小菜蛾种群控制作用评价

通过建立实验种群生命表和自然种群生命表,应用种群趋势指数(indexofpopulationtrend,I)和干扰作用控制指数(interferenceindexofpopulationcontrol,IIPC),评价花椒(Zanthoxylumbungeanum)、细叶桉(Eucalyptustereticornis)、烟草(Nicotianatabacum)、构树(Broussonetiapapyrifera)、羊蹄甲(Bauhiniavariegata)、假莲翘(Durantarepens)、飞扬草(Euphorbiahirta)、茶枯(Camelliaoleifera)8种非嗜食植物乙醇提取物对小菜蛾实验种群的控制作用,以及细叶桉、烟草、茶枯3种非嗜食植物乙醇提取物及其混合液对小菜蛾自然种群的控制作用.室内试验结果表明,在各种植物乙醇提取物作用下,I值从小到大的顺序为4.4842(细叶桉)、5.3702(花椒)、5.5199(飞扬草)、6.1609(假莲翘)、6.8937(羊蹄甲)8.0945(烟草)、9.8052(茶枯)、11.1382(构树),对照的I值为69.8964;IIPC值从小到大的顺序为0.0642(细叶桉)、0.0768(花椒)、0.0790(飞扬草)、0.0881(假莲翘)、0.0986(羊蹄甲)、0.1158(烟草)、0.1403(茶枯)、0.1594(构树),说明供试植物提取物对小菜蛾实验种群增长都有一定的抑制和干扰作用.小菜蛾自然种群生命表研究结果表明,在各种植物乙醇提取物作用下,I值从小到大的顺序为5.1997(细叶桉)、7.4160(烟草)、7.3644(茶枯)和3.1399(混合液),对照的I值为21.6232;IIPC值从小到大的顺序为混合液(0.1608)、细叶桉(0.2405)、茶枯(0.3549)、烟草(0.3695),说明供试植物提取物都能明显降低种群趋势指数,在一定程度上抑制和干扰小菜蛾自然种群增长,在生产中有一定的应用前景.     

Changes in diatom-dominated biofilms during simulated improvements in water quality: implications for diatom-based monitoring in rivers

Although benthic diatoms are used to assess river water quality, there are few data on the rate at which diatom assemblages react to changes in water quality. The aim of this study was to assess the reaction time of diatoms and to discuss the changes occurring during water quality improvement on the basis of their autecological characteristics. In order to simulate this improvement, diatom-dominated biofilms grown on artificial sandstone substrata were transferred from several polluted rivers to an unpolluted river. They were sampled three times: before transfer and 1 and 2 months after transfer. The ecology and growth-forms of the taxa explained most of the changes in species composition observed during the experiment. Adnate diatoms gradually replaced motile and stalked taxa. Gomphonema parvulum, a stalked diatom positioned vertically in the biofilm, is adapted for light and space competition in high-density algal biofilms. When transferred to an unpolluted site, this growth-form is less competitive and does not tolerate the high grazing pressure. Fistulifera saprophila is a single celled motile diatom, living in organic matrices. When the artificial substrata were transferred to the unpolluted site, this particular ecological niche disappeared quickly. On the other hand, Achnanthidium minutissimum, which is considered to be cosmopolitan and an early colonizer, increased during the first month of transfer and then decreased. It was gradually replaced by A. biasolettianum, which was the taxon best suited to this pristine stream. The changes observed differed between treatments depending on the species composition and architecture of the biofilms. In particular, biofilms dominated by stalked and motile diatoms were more quickly modified than those dominated by small motile diatoms. The diatom index reflects these changes, and its values showed that about 60 days following a water quality improvement were necessary for transferred diatom assemblages to reach diatom index values similar as those at the unpolluted river.     

呼气末二氧化碳分压、C-反应蛋白/白蛋白比值及综合脱机指数对重型颅脑损伤机械通气患者撤机失败的预测价值

摘要 目的：探讨呼气末二氧化碳分压（PetCO₂）、C-反应蛋白/白蛋白比值（CRP/Alb）及综合脱机指数（IWI）对重型颅脑损伤机械通气患者撤机失败的预测价值。方法：选择2020年1月至2022年6月在安徽中医药大学附属六安医院进行机械通气的重型颅脑损伤患者96例作为研究对象,按照撤机结局分为撤机失败组（n=31）和撤机成功组（n=65）。比较两组撤机前PetCO₂、CRP/Alb、IWI及临床参数。应用多因素Logistic回归分析重型颅脑损伤机械通气患者撤机失败的危险因素。应用受试者工作特征（ROC）曲线评价PetCO₂、CRP/Alb、IWI对重型颅脑损伤机械通气患者撤机失败的预测价值。结果：撤机失败组PetCO₂、CRP/Alb、急性生理功能和慢性健康状况评分系统II（APACHE II）评分显著高于撤机成功组,机械通气时间长于撤机成功组,IWI、格拉斯哥昏迷评分（GCS）显著低于撤机成功组（P<0.05）。多因素Logistic回归分析显示,PetCO₂≥37.01 mmHg、CRP/Alb≥0.97、IWI≤78.23、GCS≤5.90分、APACHE II评分≥26.17分、机械通气时间≥4.49 d是重型颅脑损伤机械通气患者撤机失败的危险因素（P<0.05）。ROC曲线分析结果显示PetCO₂、CRP/Alb、IWI、GCS、APACHE II对重型颅脑损伤机械通气患者撤机失败均有较高的敏感度、特异度, PetCO₂、CRP/Alb、IWI三项联合检测对重型颅脑损伤机械通气患者撤机失败预测的曲线下面积（AUC）高于PetCO₂、CRP/Alb、IWI、GCS、APACHE II单独检测。结论：PetCO₂、CRP/Alb及IWI联合评估对重型颅脑损伤机械通气患者撤机失败具有较高的预测价值。     

齿痛消炎灵颗粒联合牙周激光对牙周炎的应用效果及对口气和舌苔指标的影响

摘要 目的：探讨齿痛消炎灵颗粒联合牙周激光对牙周炎的应用效果及对口气和舌苔指标的影响。方法：选取我院2020年7月到2023年7月收治的80例牙周炎患者,分为观察组与对照组,各40例。对照组采取常规治疗与口服齿痛消炎灵颗粒,观察组以对照组为基础,增加牙周激光治疗。对比两组患者临床疗效,对比其治疗前与治疗4周后菌斑指数（PLI）,出血指数（BI）、探诊深度（PD）、临床附着丧失（CAL）相关牙周健康指标,口气感官值（OS）、口腔挥发硫化物（VSCs）相关口气指标以及舌苔厚度（Tt）、舌苔面积（Ta）相关舌苔指标变化。结果：观察组治疗总有效率较对照组高（P＜0.05）;治疗前两组患者CAL、PD、BI、PLI水平对无差异（P＞0.05）,治疗后两组均降低,且与对照组相比,观察组较低（P＜0.05）;治疗前两组患者OS、VSCs水平对比无差异（P＞0.05）,治疗后两组均降低,且与对照组相比,观察组较低（P＜0.05）;治疗前两组患者Tt、Ta评分对比无差异（P＞0.05）,治疗后两组均降低,且观察组较对照组低（P＜0.05）。结论：齿痛消炎灵颗粒联合牙周激光治疗牙周炎效果较好,改善患者牙周健康程度,减少舌苔情况,改善口气情况。     

凝血与纤溶指标与颅脑损伤后急性创伤性凝血病的关系及对脑心综合征的预测效能研究

摘要 目的：分析凝血与纤溶指标与颅脑损伤（TBI）后急性创伤性凝血病（ATC）的关系及对脑心综合征（CCS）的预测效能。方法：选取2020年1月～2022年12月本院收治的80例TBI患者作为研究对象,分别检测并计算非ATC患者与ATC患者、非CCS患者与CCS患者的凝血酶原时间（PT）、活化部分凝血酶原时间（APTT）、D-二聚体（D-D）、凝血酶-抗凝血酶复合物（TAT）、纤溶酶-α2纤溶酶抑制物复合物（PIC）水平和国际标准化比值（INR）、TAT/PIC比值;并采用双变量Spearman相关性检验凝血与纤溶指标的相关性,建立多因素Logistic模型分析TBI后ATC和TBI合并CCS的影响因素,同时分析凝血与纤溶指标对TBI合并CCS的预测效能。结果：80例TBI患者的ATC发生率为27.50%;与非ATC组比较,ATC组PT、APTT、D-D水平较高,TAT/PIC比值较低（P＜0.05）。PT、APTT、D-D与颅脑损伤后ATC呈正相关性,TAT/PIC与ATC呈负相关性。多因素logistic分析结果显示,TAT/PIC是颅脑损伤后ATC的独立危险因素（P＜0.05）。80例TBI患者的CCS发生率为20.00%;与非CCS组比较,CCS组PT、APTT、D-D水平较高,TAT/PIC比值较低（P＜0.05）。多因素logistic分析结果显示,PT、APTT、D-D、TAT/PIC是TBI合并CCS的独立危险因素（P＜0.05）。TBI合并CCS预测中,PT、APTT、D-D的ACU均＞0.70,TAT/PIC＞0.85。结论：TAT/PIC与TBI后ATC存在一定关联,同时还能预测CCS的发生,在TBI患者预后预测方面具有指导意义。