The coconut pathosystem: weed hosts of nymphs of the American palm Cixiid Haplaxius crudus (Hemiptera: Fulgoroidea)

Lethal yellowing (LY) of coconut palm (Cocos nucifera L., Arecaceae) is a disease of economic importance that is caused by the phytoplasma ‘Candidatus Phytoplasma palmae’ and is transmitted by the planthopper Haplaxius crudus (Van Duzee) (Hemiptera: Cixiidae). This study explores the weeds used by H. crudus nymphs and other Cixiidae in a coconut pathosystem in southern Mexico. Nymphs were collected directly from the root system of each weed by hand or with the help of a vacuum after carefully opening the culm. This study included 11 species of weeds: nine Poaceae [Brachiaria decumbens Stapf, B. humidicola (Rendle) Schweick, B. mutica (Forssk.) Stapf, Digitaria abyssinica (Hochst. Ex A. Rich.) Stapf, Eustachys petraea (Sw.) Desv., Leersia hexandra Sw., Panicum laxum Sw., P. maximum Jacq., Paspalum notatum Flüggé]; one Cyperaceae [Cyperus ligularis L.], and one Portulacaceae: [Portulaca pilosa L.]. Brachiaria mutica, E. petraea, B. humidicola, P. maximum were identified as the principal host species for H. crudus nymphs. Brachiaria decumbens, D. abyssinica, and C. ligularis are new host records for the nymphs of H. crudus. Additionally, it was found that H. crudus may coexist with its cogeners H. skarphion Kramer (Cixiidae) and H. caldwelli Kramer (Cixiidae), on B. mutica. On C. ligularis, H. crudus may coexist with Oecleus snowi Ball (Cixiidae) nymphs. These results suggest that in the coconut pathosystem there is a complex of multitrophic interactions that should be considered in integrated management of LY.     

水热法制备不同形貌纳米片状MoS_2的光催化性能

二硫化钼是类似于石墨烯的二维层状材料,其优异的磁学性能、电学性能、催化性能和光学性能受到了科研人员的广泛关注.通过水热法制备出4种不同形貌的二硫化钼纳米片.对二硫化钼样品进行扫描电子显微镜测试,以200 W钨丝灯为光源,在暗箱中进行甲基橙溶液的降解测试.通过紫外可见光分光光度计对测试样品溶液进行吸光度测试,得出纳米片状的二硫化钼光催化降解甲基橙溶液降解率最高.     

Comparative genetic differentiation study of three coexisting mangrove crabs in western Atlantic

ABSTRACT

A multispecies approach may reveal the factors influencing the genetic differentiation of coexisting species along a wide geographic area. Our aim was to compare the genetic differentiation of mangrove crabs coexisting along the western Atlantic in order to verify if there are common barriers, using two mitochondrial DNA markers to quantify genetic differentiation, variance and diversity. In addition, we included a mismatch distribution to check demographic history. Our data revealed that species with similar pelagic larval duration had either high genetic differentiation or the absence of genetic structure. These results can be explained by factors that contribute to genetic differentiation, such as the presence of large estuarine areas (acting as barriers), ocean currents, and larval behaviour. Also, historical events that promoted the isolation of some areas in the past, such as glacial cycles during the Pleistocene, could have caused the observed high levels of genetic divergence in some species.     

Description of the aberrant Leptopilina lasallei n. sp., with an updated phylogeny of Leptopilina Förster (Hymenoptera: Figitidae: Eucoilinae)

ABSTRACT

In the search for native Asian parasitoids of Drosophila suzukii, the notorious spotted-wing Drosophila (SWD), an odd new species of Eucoilinae was discovered. Leptopilina lasallei sp. nov. is herein described and diagnosed relative to other eucoilines associated with drosophilid hosts. Morphologically, L. lasallei is somewhat aberrant within Leptopilina; phylogenetically, L. lasallei is sister group to the core Leptopilina. In the process of investigating L. lasallei, a de novo molecular phylogeny of Leptopilina was generated and is included here. The integrated approach used for the characterisation of L. lasallei, and the resulting phylogeny of Leptopilina, produced data useful to select parasitoid species for SWD biological control.http://www.zoobank.org/urn:lsid:zoobank.org:act:402D504A-4616-4524-85D7-1C13A6276F06 http://www.zoobank.org/urn:lsid:zoobank.org:act:402D504A-4616-4524-85D7-1C13A6276F06     

轿车涂装输送线控制网络设计

在分析轿车生产工艺的基础上,按照轿车生产的主流技术,采用地面式机械化输送模式对传统的轿车生产中涂装输送系统进行网络化控制设计。网络化控制系统采用分散控制、集中管理的主从网络控制模式,以西门子S7-300PLC作为主(操作)站和远程ET200S作为从(操作)站实现系统控制功能;并通过人机界面实现操作人员的在线状态查询和故障查询;涂装设备的控制都具备手动、自动模式切换和故障报警指示。该系统提高了轿车涂装工艺过程的自动化水平,提升了产品质量,降低了制造成本。     

李超代数S(2)上的Rota-Baxter算子

主要研究李超代数S(2)上权为0的Rota-Baxter算子, 根据S(2)_0^-与sl(2,C)同构的这一性质, 利用sl(2,C)的Rota-Baxter算子, 给出了李超代数S(2)上的权为0的偶的Rota-Baxter算子, 同时利用 Rota-Baxter算子的定义计算得到了李超代数S(2)上的权为0的奇的Rota-Baxter算子。     

遗失在中国土地上的明珠--赛珍珠抗战演说与文章之管见

中国抗日战争爆发之后，身处美国的赛珍珠参与和组织了大量的社会活动：创作小说、发表演讲、成立东西方协会、编纂《亚洲》杂志等。赛珍珠以支持抗战为主题的演说和文章都充分体现出她对中国的关注和热爱，对于“中国必胜”的信念，以及对中日民族精神和中美关系的独到见解，为中国赢得美国甚至世界各国人民的同情和支持，为中国抗战做出了不可忽略的贡献。     

基于18S rDNA序列鉴定北部湾养殖区引发藻华的一株原甲藻

高度保守的核糖体18SrDNA序列可用于经济快捷且精确地鉴定浮游植物的种类。2018年夏季,广西北部湾近海的对虾养殖区内发生了原甲藻引起的藻华,藻华的优势种密度为5.5×105 cells·L~(-1),本文采用形态学观察法结合序列分析鉴定的方法来鉴定该藻的种类。结果表明,在形态上,这株分离培养获得的原甲藻(编号BBGA-9003),其大部分细胞类似心形或卵形,少部分细胞近似三角形,鞭毛2条,细胞长和宽分别为(16.55±1.42)μm和(13.84±1.86)μm。该原甲藻经18SrDNA基因序列测定并进行BLAST分析,结果表明该原甲藻序列和GenBank中56株不同种原甲藻具有很高的同源性,在系统进化树上与不同来源的微小原甲藻聚在一大分支上,且与各微小原甲藻间的遗传距离均小于与其他种间的遗传距离。因此,从分子生物学的角度鉴定该株原甲藻属于微小原甲藻,此种藻华的发生意味着北部湾养殖区有害藻华种类多样性的增加。本研究为18SrDNA序列测定用于海洋浮游植物种类鉴定提供了实验依据,也为广西北部湾养殖区有害藻华的防治提供基础资料。     

基于 WEB 的加班管理系统研究与实现

从系统的运行架构、应用技术、数据库设计等方面系统阐述了基于WEB的加班管理系统的研究思路和实现方法。系统的建立将实现从人工制作向信息自动化管理的转型,有效加强了内部管理,严肃了劳动纪律,维护了员工权益。     

基于DPI技术LTE-S1接口流量识别系统的设计与实现

针对长期演进(long time evolution,LTE)网络,基于数据解码技术?爬虫技术和DPI技术提出了一种流量识别系统的设计与实现方案?以图书类APP应用流量识别为例,说明深度封包检测(deep package inspection,DPI)技术在S1接口流量识别系统中的设计实现过程?采用黑盒测试方法,对系统进行性能测试,通过测试结果得出结论:该流量识别系统可以实现对用户行为的监测,对细化流量经营有着重要的推广意义?