用AXUM软件绘制发酵代谢曲线

AXUM是一种专业的科学绘图软件,可由Excel、Access、SAS、SPSS等导入或直接录入数据,绘制相应二维、三维曲线。该软件具有使用方便,自定义功能强,绘制的曲线专业、美观、大方等特点。本文以Bt发酵参数为例,介绍了该软件的使用方法。     

A Network Approach for Analyzing Spatially Structured Populations in Fragmented Landscape

We extend the recently proposed graph-theoretical landscape perspective by applying some network-centric methods mainly developed in the social sciences. The methods we propose are suitable to (1) identify individual habitat patches that are disproportionally high in importance in preserving the ability of organisms to traverse the fragmented landscape, and (2) find internally well-connected compartments of habitat patches that contribute to a spatial compartmentalization of species populations. We demonstrate the utility of these methods using an agricultural landscape with scattered dry-forest patches in southern Madagascar, inhabited by the ring-tailed lemur, Lemur catta. We suggest that these methods are particularly suitable in landscapes where species’ traversability is not fully inhibited by fragmentation, but merely limited. These methods are potentially highly relevant in studying spatial aspects of resilience and in the design of natural reserves.     

Species specific connectivity in reserve-network design using graphs

Systematic conservation planning applications based solely on the presence/absence of a large number of species are not sufficient to guarantee their persistence in highly fragmented landscapes. Recent developments have thus incorporated much desired spatial design considerations, and reserve-network connectivity has received increased attention. Nonetheless, connectivity is often determined without regard to species-specific responses to habitat fragmentation. But species differ in their dispersal ability and habitat requirements, making proximate priority areas necessary for some species, while undesirable for others. We present a novel approach that incorporates species-specific connectivity needs in reserve-network design. Importantly, our method differs from previous approaches in that connectivity is not part of the objective function, but part of the constraints, thus avoiding typical undesirable trade-off that may result in high connectivity for some species but null connectivity for others. We use graphs to describe the dispersal pattern of each species and our goal is to identify minimum sets of reserves with connected sites for each of the species. This is not a trivial problem and we present three algorithms, one heuristic and two integer cutting algorithms that guarantee optimality, based on different 0-1 linear programming formulations. Applications to simulated data show that one of the algorithms that guarantee optimality is superior to the other, although both have limited application due to the number of sites and species they can manage. Remarkably, the heuristic can obtain very satisfactory solutions in short computational times, surpassing the limitations of the exact algorithms.     

机械CAD软件的二次开发

 介绍基于AutoCAD开发机械CAD软件的方法,包括数据管理、形位公差标注、标准件建库等问题,所开发的软件符合国家有关制图标准。     

Early intracellular punctures by two aphid species on near-isogenic melon lines with and without the virus aphid transmission (Vat) resistance gene

The Vat resistance gene (in Cucumis melo L.) inhibits the transmission of non-persistent viruses by Aphis gossypii Glover, but does not affect transmission by Myzus persicae (Sulz.). To see whether this difference was behaviourally determined, we investigated the stylet penetration behaviour of these two aphid species by recording EPGs (Electrical Penetration Graphs) of 8 and 20 min on two sets of susceptible and resistant isogenic melon lines. During the 20 min EPG study, inoculation with CMV (Cucumber Mosaic Virus) was also investigated. For both sets of isogenic lines, the two aphid species were able to detect the presence of Vat. The mean duration of individual intracellular punctures on the resistant genotypes was significantly reduced for both M. persicae and A. gossypii (-10% and -8% respectively for duration of pattern ‘pd’ in the 20 min experiment); this reaction appeared faster for M. persicae, a species for which melon was not a suitable host-plant. Therefore, in contrast to Vat's anti-transmission effect, this behavioural effect was not aphid species-specific. Also, the frequency of intracellular punctures on the resistant genotypes was significantly reduced in A. gossypii (but not in M. persicae): on average, this frequency dropped from ≈0.65 pd.min^-1 on the susceptible genotypes to ≈0.5 pd.min^-1 on the resistant ones. It was concluded that (intracellular?) chemical cues were detected very early by aphids probing on the resistant genotypes carrying the Vat gene. However, a comprehensive analysis of the behavioural traits of both aphids on the two genotypes could not alone account for the complete inhibition of transmission which was found only to occur for A. gossypii on resistant genotypes. None of the differences detected (between aphid species or between plant genotypes) could account for the Vat phenotype, although they may explain quantitative differences in transmission efficiencies between aphid species. It was thus concluded that Vat effect was primarily chemically mediated. Finally, some intracellular punctures bearing typical subphases have been identified in both aphid species and were designated as ‘long potential drops’ (pd-L). For A. gossypii, these were observed early after plant contact and their mean duration was twice that of standard intracellular punctures (≈8.5 s vs ≈4.2 s). Although not necessary for CMV inoculation, the duration of such phases was positively correlated with a high transmission efficiency by A. gossypii on the susceptible genotype. The nature of this pattern and a putative mechanism of action of the Vat gene are discussed.