Complementary insects

The fight against fruit flies (Ceratitis capitata) has entered a new stage. The flies lay their eggs inside ripe fruits and are thus a major pest for fruit growers in the tropics and subtropics. A new combination of two known techniques has turned out to be successful in the United States and Mexico, and recently Brazil has implemented the combined control programme. On the one hand, the programme concerns mass rearing of sterile males and releasing them, a practice already used in many parts of the world. On the other, it involves releasing a parasitic wasp (Diachasmimorpha longicaudata) which, once established in an infested area, starts to prey on the fruit flies. The new approach involves releasing both the wasp and the sterile male fruit flies simultaneously in large numbers.. The sterile flies reduce the number of fertile eggs. The wasps seek out the larvae of the flies in the fruits, feeds on them and lay their own eggs inside them. In this way, the wasp reproduces itself and its offspring continues the struggle against the fruit fly. The Brazilian Agricultural Research Organisation (EMBRAPA) has tested the method in various ecosystems in the country and has found that it is a viable biological control method, usable at a large scale and thus saving on pesticides. [caption to illustration] It s the quiet, small ones you have to watch out for. This pesky Ceratitis capitata is about 6 times smaller than in this photo. Embrapa Mandioca e Fruticultura 44.380-000, Cruz das Almas, Bahia, Brazil Fax: + 55 75 621 1118 Email: [email protected] Website: www.cnpmf.embrapa.brThe fight against fruit flies (Ceratitis capitata) has entered a new stage. The flies lay their eggs inside ripe fruits and are thus a major pest for fruit growers in the tropics and subtropics. A new combination of two known techniques has turned..

黄河流域洪水对入海泥沙通量的影响

利用1950～1985年大样本洪水资料,研究了黄河流域洪水过程中三黑小所控制的流域水沙条件与入海泥沙通量和通量系数的关系,分析了泥沙通量与流域水量、沙量和平均流量的关系。在三黑小沙量与入海泥沙通量的关系中,从量上看,黄河下游河道具有“多来多排”的特性;从比例上看,具有“多来多淤”的特性。不同来源区洪水对泥沙通量和通量系数具有不同的影响,平均每场洪水泥沙通量按大小排序依次是:多沙粗沙区、下少沙区、上少沙区和多沙细沙区。通量系数按大小排序依次是:下少沙区、上少沙区、多沙细沙区和多沙粗沙区

基于最短路径敏感度的光网络关键链路识别

电力光网络的关键链路对业务质量的安全和可靠保障具有重要作用。关键链路识别方法的研究有助于提高识别过程的高效性和准确性。文章首先将最短路径敏感度作为网络效能测度,并通过计算网络节点间最短路径长度,研究链路状态恶化对网络效能的影响;然后,基于跳数最少、时延最短和可靠性最高等3种不同目标,对链路状态变化与最短路径敏感度关联关系进行统计分析,得到关键链路指标;最后,以实际的省级电力通信网为算例,验证方法的可行性和正确性。研究结论对电力光网络的规划设计和运行维护具有参考价值

Preparation and characterization of nanometer sized TiO_2 thin film sintered at low temperature

[中文文摘]采用改进的溶胶-凝胶法令TiO2在普通玻璃载玻片表面浸渍提拉成膜,再经150℃热处理15min。用阶梯厚度仪、XRD、SEM、XPS、AFM、UV-vis吸收光谱和降解亚甲基蓝实验对所成薄膜的厚度、晶粒大小、表面形貌、吸光性和光催化性能进行了表征。研究结果表明:薄膜为类微晶玻璃态,其纳米粒子晶型为单一锐钛矿型,粒径在10~50nm,薄膜表面均匀、致密,具有良好紫外-可见吸收性和光催化活性。[英文文摘]The TiO2 thin film prepared by an improved sol-gel processing and then dip-coating on a glass substrate was sintered at 150℃ for 15min.The grain size,the thickness,the surface property,and the absorbency in UV-vis spectra of the film were characterized by a surface profile and methods of X-ray diffraction,scanning electron microscopy,atomic force microscopy,X-ray photoelectron spectroscopy,UV-vis spectrophotometry and decomposition of methylene bule.The film is identified as pure anatase,the grain size is around 10-50nm and t he surface of t he film is even and compact , the film shows high light absorption in UV-vis spectra and has high photocatalytic decomposition rates of met hylene bule.国家自然科学基金资助项目(50472057

中国现代花粉数据集

孢粉是重建古植被、古气候的重要基础数据。孢粉数据库对研究样点至区域和全球尺度上的古环境演变规律、古气候变化特征反演和古生物地球化学循环模拟等具有重要意义。该文收集整理了中国1960–2020年间发表和部分未发表的现代花粉数据记录,包括样品编号、采样位置、采样地经纬度和海拔高度、样品类型、数据来源、数据类型、周边植被信息、参考文献、花粉类群及其含量等信息;并对数据进行筛选和标准化等处理,由此整合为中国现代花粉数据集。该数据集由4 497个现代花粉采样点的数据信息组成,包括660个来自中国第四纪孢粉数据库数据,1 763个前期整理发表的数据和2 074个近期收集的数据,涵盖772个花粉类群。样品类型以土壤表层样品(3 332个)为主,苔藓样品以及湖泊、海洋表层样品等为辅,广泛分布于全国不同地理区域和植被类型中,其中以温带荒漠区域(24.91%)和亚热带常绿阔叶林区域(24.02%)最丰富,其次为温带草原区域(16.14%)和青藏高原高寒植被区域(15.83%)。数据按照来源可分为原始数据(58%)和数值化数据(42%);按照数据类型可分为原始统计粒数的样点(59%)和以花粉百分比表达的样点(41%)。半个多世纪以来,科研人员开展了大量的表层现代花粉取样和研究。本数据集虽然仅获取部分记录,但样点覆盖了我国绝大多数地区,可有效地用于古植被与古气候重建的现代孢粉与现代植被校验,并将为中国孢粉数据库的建立与更深入的孢粉研究提供数据支撑

20世纪80年代末以来中国土地利用变化的基本特征与空间格局[J]

土地利用/土地覆被变化(LUCC)是人类活动与自然环境相互作用最直接的表现形式,本文采用相同空间分辨率的卫星遥感信息源和相同的技术方法,对中国1980年代末到2010年土地利用变化数据进行定期更新。在此基础上,提出并发展土地利用动态区划的方法,研究土地利用变化的空间格局与时空特征。我们发现:1990-2010年的20年间,中国土地利用变化表现出明显的时空差异。"南减北增,总量基本持衡,新增耕地的重心逐步由东北向西北移动"是耕地变化的基本特征;"扩展提速,东部为重心,向中西部蔓延"是城乡建设用地变化的基本特征;"林地前减后增,荒漠前增后减,草地持续减少"是非人工土地利用类型变化的主要特征。20世..