Geochemical fluxes in forested acidified catchments     

Jörg Matschullat  Peter Kritzer  Willy Maenhaut 《Water, air, and soil pollution》1995,85(2):859-864

The atmospheric deposition of some major components (e.g., NO₃-N 6.6 and 14.5; SO₄-S 17.8 and 42.4 kg ha^–1 a^–1) and trace elements (e.g., Cd 0.4 and 1.1, Cu < 1.9=" and=" 15,=" pb=" 43=" and=" 48=" g=">^–1 a^–1) in bulk and throughfall deposition respectively, shows a pronounced decline in recent measurements of total deposition in the eastern Erzgebirge (Germany). This is true for both bulk and throughfall deposition in 1992–1994 as compared to similar data from 1985–1989. The decline is a result of successful emission control strategies in central Europe and the shut down of plants and factories in the former GDR.The dry deposition at the highest (influenced by long-range transport) and the lowest station (local influences) shows distinct differences (e.g., Cd 0.6 and 0.3; Cu 17.4 and 7.3; Pb 13 and 31 ng m^–3). A comparison between total and dry deposition exhibits the different behavior of elements in respect to atmospheric concentrations and solubility in (rain)water. Anthropogenically released elements are mainly immited via wet deposition.  相似文献   

基于双土槽试验研究的黄土坡面侵蚀产沙过程   总被引：1，自引：1，他引：1       下载免费PDF全文

肖培青  郑粉莉  贾媛媛 《中国水土保持科学》2003,1(4):10-15

 定量分析梁峁坡面各侵蚀带之间侵蚀过程中的相互作用及其影响机理,将为坡面侵蚀预报模型的建立提供重要的理论基础。利用供沙土槽和试验土槽双土槽径流小区,研究不同上方汇流含沙量、不同降雨强度和不同地表面条件下的黏黄土陡坡面(15°)上方汇流汇沙,对坡下方侵蚀产沙过程的影响。研究结果表明:上方汇流汇沙对坡面侵蚀产沙过程有重要影响,上方来沙不但被径流全部搬运,而且上方来水在试验土槽引起了净侵蚀产沙量,坡面侵蚀现象为侵蚀-搬运过程占主导地位。对于疏松土和紧实土处理,上方汇流引起坡下方的净侵蚀产沙量,分别占试验土槽全部产沙量的31.1％-97.3％和45.1％-89.7％。上方汇流引起坡下方净侵蚀产沙量随降雨强度的增加而增加,同时受土壤容重和下垫面细沟侵蚀发展过程的综合影响。土壤容重影响坡面侵蚀的发生和发展,而坡面侵蚀产沙过程与细沟发育过程相对应。  相似文献   

Transport of the oval squid Sepioteuthis lessoniana Férussac, 1831 in Lesson 1830–1831 (Cephalopoda: Loliginidae) for up to 24 h and subsequent transfer to an aquarium     

Yuzuru  IKEDA  Yukio  UETA  the late Ikuko  SAKURAZAWA  the late Gen  MATSUMOTO 《Fisheries Science》2004,70(1):21-27

  相似文献   

Potential as an aerosol vaccine of an improved Newcastle disease vaccine derived from the LaSota strain—II. In vivo studies     

N Zygraich  F Renaut  J Gits 《Comparative immunology, microbiology and infectious diseases》1978,1(1-2):59-66

Aerosol administrations of RIT 4030 and other available vaccine strains have been carried out in SPF and in conventional chickens. The results indicate that the RIT 4030 and Ulster 2C strains are significantly less reactogenic than the LaSota and the Hitchner B1 strains.The RIT 4030 strain produces an immune response even when administered to chickens with maternal antibodies and induces a better protection to challenge than the Ulster 2C strain.The replication of the RIT 4030 strain in the respiratory tract will be discussed with respect to its attenuation and transmissibility.  相似文献   

Immune responses of barramundi, Lates calcarifer (Bloch), after administration of an experimental Vibrio harveyi bacterin by intraperitoneal injection, anal intubation and immersion     

Crosbie PB  Nowak BF 《Journal of fish diseases》2004,27(11):623-632

Barramundi, Lates calcarifer (Bloch), were immunized with an experimental Vibrio harveyi bacterin via intraperitoneal injection, immersion and anal intubation. Both specific and non-specific immune parameters were measured to compare responses to bacterin after delivery by various methods. Elevated antibody activities in sera were found in all treatment groups with barramundi injected intraperitoneally displaying significantly higher antibody activity than the other groups. In addition, there was evidence of memory induction with a heightened antibody response in the intraperitoneally injected group only. Bacteriostatic assays indicated activity against V. harveyi in the sera of all bacterin-treated groups; again this activity was significantly higher in the intraperitoneally injected groups. There was no enhancement noted in head kidney macrophage phagocytic activity or in serum lysozyme levels.  相似文献   

乌鲁木齐冬季大气中黑碳气溶胶污染特征   总被引：1，自引：0，他引：1  

李帅  郭志忠  胡列群  何清  胥志德 《干旱区研究》2012,29(4):727-734

利用乌鲁木齐大气成分站观测的黑碳（BC）气溶胶质量浓度、主要污染物浓度以及相关气象资料,对该地区冬季BC类气溶胶的日变化、小时变化及影响因子进行分析。结果表明： 乌鲁木齐冬季BC质量浓度平均为6.55 μg/m³,日较差较大,与API、PM₁₀、PM_2.5、PM_1.0、NO_x的日变化具有较好的相关性;BC质量浓度的小时变化具有明显的双峰特征,这与机动车排放污染、居民活动和冬季采暖燃煤等相关联; BC质量浓度出现频率主要在2～9 μg/m³,占所有观测的60%; 乌鲁木齐冬季BC质量浓度明显高于国外某些城市,与国内同类大城市的观测结果比较,其浓度相对较低;冬季从北、西北方向过来的气团易造成BC高污染;风速大于1.0 m/s时,BC质量浓度开始下降,下降幅度接近50％,当风速超过2 m/s时,风速与BC质量浓度之间没有明显相关性;工作日BC质量浓度略高于周末,周末BC质量浓度曲线比工作日推迟1 h左右。  相似文献   

整合CALIS、CASHL、NSTL文献传递系统实现文献资源全面共享     

康美娟 《农业图书情报学刊》2012,24(10):31-33

在比较了CALIS、CASHL和NSTL三大文献传递系统的基础上,论述了整合三大系统的可行性与必要性,同时阐述了三大文献传递系统整合的主要内容。  相似文献   

Aerosol delivery of trail pheromone disrupts the foraging of the red imported fire ant,Solenopsis invicta     

David Maxwell Suckling  Lloyd D Stringer  Joshua E Corn  Barry Bunn  Ashraf M El‐Sayed  Robert K Vander Meer 《Pest management science》2012,68(12):1572-1578

BACKGROUND: The fire ant, Solenopsis invicta, is one of the most aggressive and invasive species in the world. The trail pheromone Z,E‐α‐farnesene (91% purity) was prepared, and disruption of worker trail orientation was tested using an ethanol‐based aerosol formulation presenting a single puff of this compound by airbrush and compressed air. Trail‐following behaviour was recorded by overhead webcam and ants digitised before and after presentation of the aerosol treatment at four rates (1.6, 16, 160 and 1600 ng cm^?2). RESULTS: Ants preferred 110 ng cm^?1 over 11, 1.1 and 0.11 ng cm^?1 for trail following. Within seconds of presentation of 1600 ng cm^?2, the highest dose tested, trail disruption was observed. Disruption was evident as reduced arrival success and reduction in the trail integrity statistic (r²), as well as increased deviation from the trail (deg). The distribution of walking track angles was also flattened. CONCLUSIONS: The feasibility of using aerosol for delivery of trail pheromone was demonstrated, but the need for high purity combined with the difficulty of commercial supply makes this technique impractical. However, the commercial production of Z,E‐α‐farnesene of high purity by industrial biotechnology or from (E)‐nerolidol may be possible in future, which would facilitate further development of trail pheromone disruption of S. invicta. Copyright © 2012 Society of Chemical Industry  相似文献   

Vertical distribution of sand-dust aerosols and the relationships with atmospheric environment   总被引：1，自引：0，他引：1  

Jie ZHANG  XingMing LI 《干旱区科学》2012,4(4):357-368

The vertical distribution of aerosols in the troposphere is important for determining their effects on climate.The vertical distribution of aerosols under different atmospheric conditions in the free troposphere was directly observed using a surface micro-pulse LIDAR(MPL) and a TP/WVP-3000 microwave radiometer at the Semi-Arid Climate & Environment Observatory of Lanzhou University(SACOL,35.95°N,104.10°E) in the western Loess Plateau,China,in the spring of 2008.The results showed two possible transportation paths of a sandstorm from May 1 to May 4 in 2008.In one path,sand-dust aerosols were transported toward the east from the Taklimakan Desert to the Badain Jaran Desert and the Tengger Desert by a westerly wind and then toward the southeast to Jingtai and Lanzhou.A weak aerosol index(AI) indicated another possible transport path toward the east from the Taklimakan Desert to the Qaidam Basin and through the Tibetan Plateau eastward to SACOL.The aerosol profile of sandstorm processes over the SACOL area displayed three patterns:a single peak distribution under stable atmospheric conditions,indicating urban aerosol distribution;an exponential decrease under unstable atmospheric conditions in the presence of a sandstorm;and a slight change in the mixed layer during the first and last stages of the sandstorm,indicative of thorough mixing during lifting and deposition stages.Analyses of the aerosol layer height(ALH) showed that there are two types of ALH diurnal variation.The ALH during the first sandstorm stage was complex and disordered,and affected by atmospheric circulation.While the ALH had obvious diurnal variation in the other stage,the ALH and aerosol extinction coefficient(AEC) had a single peak,and was higher in the afternoon and lower in the morning.In the second case the ALH was in agreement with the atmospheric boundary layer height(BLH) variation.As a result of the development of the atmospheric boundary layer(ABL) during day and maintenance at night,ALH during sandstorm-free days showed obvious diurnal variations.Multiple vertical distribution patterns of sand-dust aerosols will result in different climate effects;therefore,the vertical distribution patterns can be used to parameterize climate and aerosol models.  相似文献   

WRF-Chem中沙尘天气过程对模式分辨率及边界层方案的敏感性试验     

杨贵成 《安徽农业科学》2012,(6):3462-3466

利用数值模式WRF-Chem对兰州大学半干旱气候与环境观测站(SACOL)所在地区2010年4月10～11日的沙尘天气过程进行了水平分辨率分别为10、3和1 km的模拟分析。在每个试验中分别采用了YSU和MYJ边界层方案。结果表明,3种分辨率的试验都较好地反映了沙尘天气过程中PM10随时间的变化特征,显示出WRF-Chem对沙尘天气过程具有良好的模拟能力,但是在复杂地形区域,模式分辨率的提高并不能相应提高模拟结果的精度。在该试验中,采用MYJ边界层方案对PM10的模拟效果优于YSU方案,反映出在热通量对整个过程不具有决定性影响的情况下,MYJ方案取得了更加接近实际的结果。  相似文献