A Novel Gelatin-Based Sustained-Release Molluscicide for Control of the Invasive Agricultural Pest and Disease Vector Pomacea canaliculata

Pomacea canaliculata, one of the 100 most destructive invasive species in the world, and it is an important intermediate host of Angiostrongylus cantonensis. The molluscicides in current use are an effective method for controlling snails. However, most molluscicides have no slow-release effect and are toxic to nontarget organisms. Thus, these molluscicides cannot be used on a large scale to effectively act on snails. In this study, gelatin, a safe and nontoxic substance, was combined with sustained-release molluscicide and was found to reduce the toxicity of niclosamide to nontarget organisms. We assessed the effects of gelatin and molluscicide in controlling P. canaliculata snails and eggs. The results demonstrated that the niclosamide retention time with 1.0% and 1.5% gelatin sustained-release agents reached 20 days. Additionally, the mortality rate of P. canaliculata and their eggs increased as the concentration of the niclosamide sustained-release agents increased. The adult mortality rate of P. canaliculata reached 50% after the snails were exposed to gelatin with 0.1 mg/L niclosamide for 48 h. The hatching rate of P. canaliculata was only 28.5% of the normal group after the treatment was applied. The sustained-release molluscicide at this concentration was less toxic to zebrafish, which means that this molluscicide can increase the safety of niclosamide to control P. canaliculata in aquatic environments. In this study, we explored the safety of using niclosamide sustained-release agents with gelatin against P. canaliculata. The results suggest that gelatin is an ideal sustained-release agent that can provide a foundation for subsequent improvements in control of P. canaliculata.     

本原极小强连通有向图1—指数的下界

本文给出了n阶本原极小强连通有向图1-指数的下图:expD(1)4.且这个下界是可以达到的.     

A Connes-amenable, dual Banach algebra need not have a normal, virtual diagonal

Let be a locally compact group, and let denote the space of weakly almost periodic functions on . We show that, if is a -group, but not compact, then the dual Banach algebra does not have a normal, virtual diagonal. Consequently, whenever is an amenable, non-compact -group, is an example of a Connes-amenable, dual Banach algebra without a normal, virtual diagonal. On the other hand, there are amenable, non-compact, locally compact groups such that does have a normal, virtual diagonal.

     

AN INDIVIDUAL‐BASED MODEL FOR FERAL HOGS IN GREAT SMOKY MOUNTAINS NATIONAL PARK

The expansion of feral hog (Sus scrofa) populations in the United States has resulted in increased efforts to develop and implement control strategies designed to minimize the impacts done by this invasive species. We describe an individual‐based model for feral hogs in Great Smoky Mountains National Park (GSMNP). The objectives of the model are to provide an understanding of the population dynamics of this feral hog population and to determine the efficacy of the annual harvest as a population control method. Results suggest that the dynamics of the population are driven by fall hard mast production and the GSMNP harvests currently limit growth of the population, but these control efforts have not reduced the population.     

极小拟(k+1)连通图的最小度

给出了极小拟5连通图有围长大于或等于4的极小拟（k）＋1连通图的最小度。     

外来种喜旱莲子草的克隆生长特性

通过对外来种喜旱莲子草（Alternanthera philoxeroides（Mart．）Griseb）生长指标的测定和分析，研究了它的克隆生长规律，并探讨丁它的觅食行为．在一个生长季节内，喜旱莲子草生物量增加了近30倍，一级葡萄茎分株数增加了近50倍，最长的一级葡萄茎长度增长了近40倍，一级葡萄茎总长度增长了近13倍；一、二、三级葡萄茎上的总分株数增加了近130倍，3个级别匍匍苇总长度增长了近28倍．通过各级葡萄茎个数，葡萄茎总长度和葡萄茎总分株数比较发现，二级葡萄茎比一、二级葡萄苇生长的都要快，而一级葡萄茎的间隔物平均长度远远大于二级和三级葡萄茎．克隆植物的觅食行为与它的克隆生长紧密相连，从觅食行为来看，喜旱莲子草克隆构型随生长季节的变化说明了它对生长季节具有很强的适应性．这种快速克隆生长的特性和对生长季节的适应性有利于喜旱莲子成功入侵新的生境。     

Fatness and thinness of uniform Cantor sets for doubling measures

Let E = E({nk},{ck}) be a fat uniform Cantor set. We prove that E is a minimally fat set for doubling measures if and only if (nkck)p = ∞ for all p < 1 and that E is a fairly fat set for doubling measures if and only if there are constants 0 < p < q < 1 such that (nkck)q < ∞ and (nkck)p = ∞. The classes of minimally thin uniform Cantor sets and of fairly thin uniform Cantor sets are also characterized.     

On Harmonic Majorization of the Martin Function at Infinity in a Cone

This paper shows that some characterizations of the harmonic majorization of the Martin function for domains having smooth boundaries also hold for cones.     

光照和氮素对外来植物凤眼莲生长和生理特性的影响

通过研究不同光照和氮素营养处理的外来植物凤眼莲的生长、生物量分配、硝酸还原酶活性、游离氨基酸以及可溶性蛋白质含量变化，探讨其对环境适应性的生理学机制。凤眼莲表现出极强的可塑性，随光照和氮素营养的增加，凤眼莲生长速率明显加快，氮素代谢关键酶硝酸还原酶活性上升。根部吸收的硝酸根离子大部分运输到叶片中还原，氮素同化效率高。氨基酸含量和可溶性蛋白质含量呈现明显的变化，叶片可溶性蛋白质含量与根冠生物量分配显著相关。本研究表明风眼莲对光照和氮素表现出很强的适应性，其快速生长和高可塑性依赖于对环境变化的牛理响廊。