Invertebrate Sampling in the Substratum of an Experimental Recirculating Stream

In order to determine the efficacy of sampling benthic invertebrates to a depth of 100 mm as compared with 200 mm, the gravel substratum of an experimental recirculating stream was sampled to both depths. Except for 6 taxa which were significantly more numerous in the shallower samplers, there was no significant difference between the densities determined from the two depths.     

The influence of sampling method on the classification of wetland macroinvertebrate communities

Macroinvertebrate communities sampled by a corer, plankton net and sweep net from five wetlands on the Swan Coastal Plain were compared. The composition of the fauna collected in sweeps and tows was generally similar and differed from that collected in the cores. Cores caught fewer species than tows and sweeps at all wetlands and did not capture fast swimming hemipterans or less abundant taxa. The highest species richness was recorded in sweep samples in four out of the five wetlands. Classification (TWIN-SPAN) and ordination (SSH) of the samples collected in sweeps and tows gave good separation of the wetlands, whereas classification of core samples did not. Coring appeared to be the least suitable sampling method for describing the major components of the macroinvertebrate communities of these wetlands. Plankton tows were useful if the time available for sorting was limited as these samples were free of sediments and generally gave similar results to those obtained with sweeps. Sweeps appeared to be the most useful method for a large classification study as they collected more species and resulted in the best discrimination amongst wetlands.     

Recommendations for the routine sampling of diatoms for water quality assessments in Europe

Many methods for using diatoms for routine monitoring of water quality have been developed in Europe and, in some countries, these are being used to enforce environmental legislation. In order to facilitate their wider use, particularly with respect to European Union legislation, steps are being taken to harmonize methodology. In this paper, the principles and practice of sampling are described in relation to the main habitat types encountered in Europe. Although details of methods and sampling programmes have to be tailored to particular circumstances and the overall objectives of the monitoring, a number of generalizations can be made. Where available, rocks and other hard surfaces are the preferred substrates and methods for sampling these are described. If such substrata are not available, then introduced ('artificial') substrata have many applications. Various types of introduced substrata can be used successfully, so long as some basic precautions are described. Other types of substrata such as macrophytes and macroalgae may also be useful under certain circumstances, although there is less consensus in the literature on the most appropriate methods, and of the validity of comparisons between indices computed from epiphytic and epilithic communities. When designing surveys, it is recommended that as far as possible, extremes of non-water quality factors (e.g. shade, current speed, etc) are avoided, unless these are characteristic of the system under investigation. Detailed guidelines for sampling epilithon are described. Along with the recommendations for sampling other substrata, it is hoped that these provide a framework that can be adapted to most river types in Europe. This revised version was published online in June 2006 with corrections to the Cover Date.     

生物群落多样性的测度方法VI：与多样性测度有关的统计问题

物种多样性测度是（群落的）总体参数,它们常常是未知的,需要通过抽样将它们估计出来,因此,必须了解估计量的抽样性质。本文对与一些多样性测度的均值、方差的估计和假设检验以及大、小样本分布等有关的问题作了综述。可以看出大多数多样性测度的抽样性质还不清楚,有些甚至根本就没有研究过。Ｐｉｅｌｏｕ的合并样方法和刀切法是两个比较通用的方法,用它们可以解决其中的一些问题。但相比之下,刀切法更实用。     

棉田绿盲蝽的空间分布型及其抽样模型

2009—2010年于河北省廊坊市对棉田绿盲蝽Apolygus lucorum(Meyer-Dür)的空间分布型及其抽样模型进行了研究。结果表明,绿盲蝽成虫空间分布型与其种群密度有关,当种群密度大于百株1.6头时呈随机分布,当小于百株1.6头时一般呈聚集分布;绿盲蝽若虫在不同种群密度下均呈聚集分布;绿盲蝽整个种群呈Possion分布。应用Iwao的抽样模型建立了棉田绿盲蝽的理论抽样数公式:N=(1.35/x珋)/D2。     

Modeling markers of disease progression by a hidden Markov process: application to characterizing CD4 cell decline

Multistate models have been increasingly used to model natural history of many diseases as well as to characterize the follow-up of patients under varied clinical protocols. This modeling allows describing disease evolution, estimating the transition rates, and evaluating the therapy effects on progression. In many cases, the staging is defined on the basis of a discretization of the values of continuous markers (CD4 cell count for HIV application) that are subject to great variability due mainly to short time-scale noise (intraindividual variability) and measurement errors. This led us to formulate a Bayesian hierarchical model where, at a first level, a disease process (Markov model on the true states, which are unobserved) is introduced and, at a second level, the measurement process making the link between the true states and the observed marker values is modeled. This hierarchical formulation allows joint estimation of the parameters of both processes. Estimation of the quantities of interest is performed via stochastic algorithms of the family of Markov chain Monte Carlo methods. The flexibility of this approach is illustrated by analyzing the CD4 data on HIV patients of the Concorde clinical trial.     

Responses of Glossina austeni to sticky panels and odours

The responses of male tsetse Glossina austeni Newstead (Diptera: Glossinidae) towards blue and white sticky legged panels, baited with odour attractants, and towards modified panels were studied in the Jozani forest of Unguja Island, Zanzibar. Increasing the height of the body of a standard panel from 30 to 60 or 90 cm, increased the catch two-fold. Increasing the height of the legs (from 15 to 60 or 120 cm) or raising the device more than 5 cm above the ground reduced the catch significantly. The legs of the panels were the preferred landing sites of the flies, irrespective of the height of the body of the panel. Acetone (300 mg/h) combined with cow urine (60-130 mg/h) significantly increased the catches two- to threefold during the rainy season, but not during the dry season. Acetone had no effect during the dry season and its effect during the rainy season was less consistent. There was no effect of octenol (2.5-12.5 mg/h), used alone or in combination with acetone. Likewise, the catch did not increase through the addition of cow sebum, pig urine (60-860 mg/h), pig urine combined with acetone and octenol. The observed seasonal differences in the response of G. austeni towards odours are discussed in relation to host location strategies.     

害虫防治决策的复序贯分析方法及抽样技术研究

复序贯抽样决策技术实际应用的受限 ,原因在于截止限序贯抽样模型的缺乏。本文在检验昆虫种群空间格局回归模型的基础上 ,推导出了目前国内常用检验回归模型的截止限序贯抽样模型 ,并将其运用于复序贯分析决策过程中。实例分析表明 ,对于同一种生物种群 ,在一定的精度 (D)和置信水平(tα)要求下 ,复序贯抽样决策技术可以大幅度地节约抽样成本     

Change of cholinergic transmission and memory deficiency induced by injection of β-amyloid protein into NBM of rats

The change of cholinergic transmission of ?-amyloid protein (β-AP) treated rats was studied by intracerebral microdialysis sampling combined with HPLC analysis. β-AP_1—40 was injected into nucleus basalis magnocellularis (NBM). Passive avoidance response test (step-down test) and delayed alternation task were used for memory testing. The impairment of memory after injection of β-AP_1—40 into NBM exhibited mainly the deficiency of short-term working memory. One week after injection of β-AP_1—40 the release of acetylcholine (ACh) from frontal cortex of freely-moving rats decreased significantly, and the response of cholinergic nerve ending to the action of high [K⁺] solution was rather weak. In control animals the percentage of increase of ACh-release during behavioral performance was 57%, while in β-AP_1—40-treated rats it was 34%. The temporary increase of the ACh-release of the rat put into a new place was also significantly diminished in β-AP_1—40-treated rats. The results show that the injection of β-AP_1—40 into NBM impairs the cholinergic transmission in frontal cortex, and the impairment of cholinergic transmission may be the main cause of the deficit of working memory.     

Evaluation of sticky light traps for sampling mosquito larvae

Very simply constructed aquatic sticky light traps employing a chemical solution emitting a bright light attracted large numbers of all larval instars, but few pupae of Aedes cantans in trials in England. During April numbers of larvae per trap ranged from 73±14.2 to 163±19.9, whereas dipping with a ladle yielded only 6.9±5.5 to 11.8±7.7 larvae/dip. The traps were also effective in sampling larvae of Culiseta morsitans and in Sierra Leone larvae of Aedes aegypti. It was concluded that sticky light traps could be valuable in sampling relative numbers of mosquito larvae and merited further evaluation.

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Résumé Des pièges adhésifs lumineux faciles à réaliser sont construits pour les captures des larves de moustiques. Ils sont formés de paires de boîtes de Pétri en plastique contenant une solution émettrice de lumière provenant de bâtons lumineux chimiques Cyalume^®. Chaque piège est recouvert d'une feuille de plastique de 16×16 cm enduite d'une substance qui reste adhésive sous l'eau. Les larves de moustiques attirées vers la source lumineuse viennent se coller à la feuille adhésive.Ces pièges ont été utilisés avec succès en Angleterre pour l'échantillonnage de tous les stades larvaires d'Aedes cantans, mais pas avec le même efficacité pour les nymphes. Des tests plus restreints ont montré que la technique était également utilisable pour les larves de Culiseta morsitans. Les nombres moyens d'A. cantans capturés pendant une piode de 12 h (73±14,2–163±19,9) étaient supérieux à ceux obtenus en plongeant une louche (6,9±5,5–11,8±7,7). En utilisant les pièges adhésifs lumineux, les captures moyennes de C. morsitans étaient également supérieures (12,6±4,7–35,8±8,9) contre (5,7±6,1–8,9±7,8) avec la méthode de la louche.En Sierra Leone, des stades larvaires immatures d'A. aegypti se développant dans des containers de stockage d'eau ont également pu être capturés à l'aide de ces pièges.Bien qu'une évaluation plus poussée soit encore nécessaire, il ne fait aucun doute que ces pièges adhésifs lumineux aient un intérêt considérable pour l'échantillonnage larvaire dans les sites inaccessibles, tels que les trous d'arbres ou les trous de crabes, où les méthodes d'échantillonage classiques sont souvent d'un emploi difficile.