A model of the plant-to-plant movement of aphids I. Description of the model

The plant-to-plant movement of insects in one of the factors determining the distribution of individuals in insect populations. In this report the movement of barley aphids was analyzed by a statistical model. The model is represented as the convolution of three probability functions:

1. The probability that s individuals are found on a plant at time t₀:Q(s);
2. The probability that i individuals leave the plant and remain on the ground from time t₀ to t₁:_sC_ipⁱq^s−i and p+q=1, where p and q are the proportions of individuals which do not leave a plant and which leave it once or more, respectively;
3. The probability that j individuals climb a plant between time t₀ to t₁ and stay there at time t₁:e^−λλ^j/λ^!, where λ is the mean of the individuals.

The probability that l individuals are located on a plant at time t₁ is represented by the following equation It was shown by simple experiments that the experimental populations were well fitted to the model.     

A new method of sequential sampling to classify populations relative to a critical density

A method of sequential sampling for grading population level in relation to a critical density is proposed. The method is based on the relationship and can be used without restrictions on the distribution patterns. The formulae for simple random sampling as well as for two-stage sampling are given.     

A comparative analysis on the distribution of nymphal populations of some leaf- and planthoppers on rice plant

The frequency distribution of the number of nymphs per hill of rice plant were analyzed for three species of rice leaf- and planthoppers, Nilaparvata lugens, Delphacodes striatella and Nephotettix cincticeps, based on the sampling data obtained during their last generations in the paddy field. For every species concerned, individual distributions were proved to be contagious and to fit well to the negative binomial distribution. Further, it was found that the value of negative binomial parameter k is so stable for same species that a single value of k is applicable for a series of counts with different means, whereas that k differs remarkably among different species: if the reciprocal of the weighted estimate of common k which is an adequate index measuring degree of contagiousness of the distribution, is compared among different species, it is higher in the order of Nilaparvata, Delphacodes and Nephotettix. The ecological and practical implication of constancy and heterogeneity within and among species was discussed respectively as to the value of parameter k.     

The spatial pattern in a natural population of goldenrod (Solidago altissima L.), with particular reference to its change during the shoot growth

In a natural population of Solidago altissima L., the changes in the spatial pattern of shoots in the course of growth were studied. The results obtained were summarized as follows:

1. The spatial pattern changed from clumped to random distribution as plants grew. The change seemed to be resulted from some density-dependent process acting at a small spatial scale, probably the competition for space.
2. Large plants tended to distribute themselves more uniformly over the space than the small ones but at the mature stage of growth such a difference was not obviously recognized. The process of appearance of the small-sized plants during successive periods also seemed to be dependent on local density.
3. Large plants at the early stage of growth tended to survive better, and there was a positive correlation between initial size and the size at maturity.
4. From these results, it is inferred that the change of spatial pattern from clumped to random distribution is largely due to the elimination of small shoots as the result of competition for space among individual shoots.

     

Population dynamics of the chestnut gall-wasp,Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) IV. Further analysis of the distribution of eggs and young larvae in buds using the truncated negative binomial series

Distribution pattern of eggs and the first instar larvae of the chestnut gall-wasp, Dryocosmus kuriphilus, per bud of the chestnut tree was re-examined using the truncatedPoisson and the truncated negative binomial series. The results are as follows:

1. About sixty percent of the distribution are approximated by the truncated negative binomial and another thirty percent by the truncatedPoisson . When the distribution has been approximated by the truncated negative binomial, the show scattered values, some of which are near thePoisson , but the mean value of is about 4 both in eggs and in the first instar larvae.
2. The number of buds which have not been infested by gall-wasps is resulted from various factors as follows: (a) Buds formed after the laying activity of gall-wasps has ceased; (b) Old and shrunk buds which were avoided in laying; (c) Buds in which eggs have died by the time of sampling; and (d) Buds escaping ovipositions by chance. Most of the gall-wasp-free buds located in the middle part of the shoot are accounted for the zero-class expected by the negative binomial series.
3. Brass (1958) moment method for estimating parameters of the truncated negative binomial give good precision within the range of from 1 to 10 and of from 1 to 6.
4. It is concluded that the truncated distributions used are useful for the purpose of analysis of the distribution pattern of the chestnut gall-wasp.

     

Spatial distribution of eggs by ovipositing Indian meal moths,Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

A series of increasing egg densities was obtained by releasing various numbers of female Plodia interpunctella (Hübner ) in rooms where dishes of moth rearing medium were evenly spaced on the floor. The number of larvae produced in each dish was taken as an indication of the number of eggs that had been laid. At all egg densities, the eggs were aggregated, and most of the distributions conformed quite well with the negative binormial, but the degree of aggregation denreased as mean egg density increased. The implications of the results for the development of ware-house sampling strategies are discussed.     

Accounting for variability in sample size estimation with applications to nonadherence and estimation of variance and effect size

We consider sample size calculations for testing differences in means between two samples and allowing for different variances in the two groups. Typically, the power functions depend on the sample size and a set of parameters assumed known, and the sample size needed to obtain a prespecified power is calculated. Here, we account for two sources of variability: we allow the sample size in the power function to be a stochastic variable, and we consider estimating the parameters from preliminary data. An example of the first source of variability is nonadherence (noncompliance). We assume that the proportion of subjects who will adhere to their treatment regimen is not known before the study, but that the proportion is a stochastic variable with a known distribution. Under this assumption, we develop simple closed form sample size calculations based on asymptotic normality. The second source of variability is in parameter estimates that are estimated from prior data. For example, we account for variability in estimating the variance of the normal response from existing data which are assumed to have the same variance as the study for which we are calculating the sample size. We show that we can account for the variability of the variance estimate by simply using a slightly larger nominal power in the usual sample size calculation, which we call the calibrated power. We show that the calculation of the calibrated power depends only on the sample size of the existing data, and we give a table of calibrated power by sample size. Further, we consider the calculation of the sample size in the rarer situation where we account for the variability in estimating the standardized effect size from some existing data. This latter situation, as well as several of the previous ones, is motivated by sample size calculations for a Phase II trial of a malaria vaccine candidate.     

植物竞争能力测度方法及其应用评价

植物竞争是指不同植物间对限制性资源的共同需求而产生阻碍或制约的相互关系,是生物学领域一个非常重要的方面.竞争特征可以归结为3个方面:(1)竞争强度和重要性,(2)竞争影响和反应;(3)竞争后果.基于不同的角度,形成了一系列植物竞争能力的测度系数,而特定的竞争系数通常要求与相应的试验设计相匹配,这样不同研究间的结果比较非常困难,选用哪种竞争系数来测度植物竞争关系非常困惑.本文简要总结了植物竞争能力的基本组成元素,根据竞争特征对植物竞争测度方法进行归类综述,对竞争能力系数应用领域的可适用性和其功能的局限性进行分析评价,为相关研究正确选择试验设计和测度方法提供帮助.     

嗜热菌对有机污染物的降解及其应用研究进展

有机污染物造成的环境问题日趋严重,嗜热菌具有高效降解环境有机污染物的潜力.嗜热菌在高温条件下降解有机污染物,代谢速度快,嗜温杂菌的竞争减少,同时高温环境下一些难降解有机物的溶解度和生物可利用性大大提高,有机污染物可得到快速、彻底降解.因此,嗜热菌对有机废水生物处理及有机物污染场地生物修复等意义重大.本文从嗜热菌降解有机污染物的特点、温度的影响、降解途径、降解酶及其编码基因及工程应用等角度,介绍了嗜热菌降解有机污染物的研究进展,并对嗜热菌降解有机污染物的机理、菌种资源储备、技术策略及应用研发等研究方向进行了展望.     

流域水环境污染模型及其应用研究综述

流域水环境污染模型是研究流域水环境问题的重要工具,通过对整个流域系统及其内部发生的复杂污染过程定量化描述,识别污染物主要来源和迁移途径,估算污染负荷,评价其对流域水环境的影响,可为流域规划与管理提供决策依据.本文对当前国内外广泛应用的流域水环境模型,尤其是模拟污染负荷的模型进行了系统总结,主要包括污染负荷模型(GWLF与PLOAD)、受纳水体水质模型(QUAL2E与WASP)、以及集成污染负荷与水体水质的综合流域模型(HSPF、SWAT、AGNPS、AnnAGNPS、SWMM),着重介绍各模型的结构原理与主要特点,讨论模型实际应用的局限性.此外,还对其他水质模型(CE-QUAL-W2、EFDC和AQUATOX)与综合流域模型(GLEAMS和MIKE SHE)进行了简要的总结.最后,通过对单个模型独立运用和多个模型联合运用的案例分析,探讨了流域水环境污染模型的发展趋势与应用前景.     

A critical review and a new proposal of karyotype asymmetry indices

In literature seven different methods of evaluating karyotype asymmetry – the TF%, the As K%, Stebbins' classification, the Rec and the Syi, the A₁ and the A₂, the DI, and the A – are used for the elucidation of phylogenetic relationships and taxonomic treatments within a particular group or taxon. The investigation of these seven methods reveals that the intervals used by Stebbins to separate the different types of karyotype asymmetry are very broad and only one quantitative parameter, the A₂ index, correctly describes the variation in chromosome length in a complement. A new asymmetry index (AI) is proposed to measure karyotype asymmetry and a new parameter, the CV_CI, is offered, that precisely assesses the relative variation in centromere position in a complement. The AI index, the CV_CI and the CV_CL (=A₂ × 100) have the potential to display even minor karyotypic variations. Thus, these three indices together increase the precision of results in comparison with other existing methods. All this has important consequences as regards the interpretation of the results of karyological studies.     

A review of the genus Bothynogria Borchmann, 1915 with descriptions of one new species and two new record species from China (Coleoptera: Tenebrionidae: Lagriinae: Lagriini: Lagriina)

The genus Bothynogria Borchmann, 1915 is reviewed, with a key to all known seven species provided in the present paper. A new species Bothynogria nigripennis sp. n., and two new record species for China, Bothynogria bicolor (Kollar et Redtenbacher, 1848) and Bothynogria meghalayana Merkl, 1990, are identified and redescribed. The habitus, male antennae and aedeagus are photographed and presented for all known species except for Bothynogria bhutanica. Ecological information and intraspecific variations are also provided for Bothynogria calcarata.www.zoobank.org/urn:lsid:zoobank.org:pub:5D8BFBCD-73AF-4AD4-94DE-3F24ECE31C1D.     

Nutritional constituents of mulberry and their potential applications in food and pharmaceuticals: A review

Mulberry is a fast growing deciduous plant found in wide variety of climatic, topographical and soil conditions, and is widely distributed from temperate to subtropical regions. Due to presence of valuable phytochemical constituents, mulberry as a whole plant has been utilized as a functional food since long time. Mulberry fruits are difficult to preserve as they have relatively high water content. Therefore for proper utilization, different value-added products like syrups, squashes, teas, pestil sand köme, pekmez (turkuish by-products), yogurts, jams, jellies, wines, vinegar, breads, biscuits, parathas, and many more are made. In overseas, these value-added products are commercially sold and easily available, though in India, this versatile medicinal plant is still missing its identity at commercial and industrial scale. Leaves of mulberry are economically viable due to their important role in the sericulture industry since ancient times. Mulberries or its extracts exhibit excellent anti-microbial, anti-hyperglycaemic, anti-hyperlipidemic, anti-inflammatory, anti-cancer effects and is used to combat different acute and chronic diseases. Different parts of Morus species like fruits, leaves, twigs, and bark exhibit strong anti-tyrosinase inhibition activity that makes it a suitable candidate in cosmetic industries as a whitening agent. The current review provides a comprehensive discussion concerning the phytochemical constituents, functionality and nutraceutical potential of mulberry and as a common ingredient in various cosmetic products.     

A review of fish-derived antioxidant and antimicrobial peptides: their production, assessment, and applications

Fishes are rich sources of structurally diverse bioactive compounds. In recent years, much attention has been paid to the existence of peptides with biological activities and proteins derived from foods that might have beneficial effects for humans. Antioxidant and antimicrobial peptides isolated from fish sources may be used as functional ingredients in food formulations to promote consumer health and improve the shelf life of food products. This paper presents an overview of the antioxidant and antimicrobial peptides derived from various fishes. In addition, we discuss the extraction of fish proteins, enzymatic production, and the techniques used to isolate and characterize these compounds. Furthermore, we review the methods used to assay the bioactivities and their applications in food and nutraceuticals.     

Development and applications of destruxins: A review

The insecticidal and phytotoxic activities of destruxins (dtxs) have been well studied. The cyclodepsipeptides, which are dtxs mainly isolated from the fungus Metarhizium anisopliae and other fungi, have been well characterized in vitro and in vivo. A succession of important function, such as antitumoral, antiviral, insecticidal, cytotoxic, immunosuppressant, phytotoxic, and antiproliferative effects have been observed. To date, 39 dtxs derivatives have been identified. Dtxs possess a variety of biological activities, including acting as virulence factors for specific insects, a V-ATPase inhibitor that provides a basis for the development of new drug to against osteoporosis, cancer, or biological control agents, etc. Here, we focus on some of the research progress made on understanding dtxs during the last decade, introduce some of the newly identified dtx members, especially from M. anisopliae, and give an overview of the applications of dtxs. Using the dtxs to learn about and moderate biological events has advanced significantly during the past year. We believe that several ongoing dtx application fields may benefit from the reviewed information herein.