Protective and treatment measures against major harmful organisms in cotton-growing belt of Xinjiang     

Received date: -- Foundation item: Supported by Light of Western Regions Project  Key Project of CAS Integrated Demonstration Project for Sustainable Development of Cotton in Xinjiang with High Quality High Yield Technique LU Zhaozhi  CHEN 《地理学报(英文版)》2000,(3)

1 Harmful Organisms in Xinjiang Cotton-Growing BeltThe harmful organisms in Xinjiang cotton-growing belt are mainly diseases, insects and weeds. The diseases include Verticillium albo-atrum, cotton-root decaying disease and cotton-boll decaying disease, while the harmful insects include cotton aphids (Aphis gosspii), cotton mites, cotton boll-worms (Heliothis armigera), cotton thrips (Thrips. sp), Lygus pratersis and cutworms. Their harmful effects vary in different places but all of them …  相似文献   

全数字、全自动精确获取地理信息的产品--高分辨率航空立体相机HRSC-A     

赫建忠 《测绘与空间地理信息》2000,23(4):5-6,17

介绍了最初为火星飞行计划而开发的数字相机的各种可能的航空应用.这种多光谱、多线条和多立体遥控自动扫描设备能提供分辨率为10～20cm的数字正射影像和数字地面模型.当测量高度为6000m时,像素尺寸为24cm,并且在x,y方向的精度为 20cm,z方向的精度为 30cm.从1997年5月进行第一次航空试验以来,HRSC-A系统已经成功地应用在各种领域.本文是结合DLR、ISTAR(法国)和Geodan geodesie(荷兰)的共同努力而完成的,对电信网络规划、GIS应用、3D模型、环境监测、地图制图/地图更新和可视化等应用领域进行了重点试验.  相似文献   

The harmonic and sideband structure of the kilohertz quasi-periodic oscillations in Sco X-1     

Mariano Méndez  Michiel van der Klis 《Monthly notices of the Royal Astronomical Society》2000,318(3):938-942

We use data from the Rossi X-ray Timing Explorer to search for harmonics and sidebands of the two simultaneous kilohertz quasi-periodic oscillations (kHz QPOs) in Sco X-1. We do not detect any of these harmonics or sidebands, with 95 per cent confidence upper limits to their power between ∼1 and ∼10 per cent of the power of the upper kHz QPO. The oscillations produced at these frequencies may be attenuated in a scattering corona around the neutron star. We find that upper limits to the unattenuated power of some of the strongest theoretically predicted harmonics and sidebands are as low as ∼2 per cent of the unattenuated power of the high-frequency QPO in Sco X-1.  相似文献   

Origin of freshwater and polynya water in the Arctic Ocean halocline in summer 2007     

Dorothea Bauch  Michiel Rutgers van der Loeff  Nils Andersen  Sinhue Torres-Valdes  Karel Bakker  E. Povl Abrahamsen 《Progress in Oceanography》2011,91(4):482-495

Extremely low summer sea-ice coverage in the Arctic Ocean in 2007 allowed extensive sampling and a wide quasi-synoptic hydrographic and δ¹⁸O dataset could be collected in the Eurasian Basin and the Makarov Basin up to the Alpha Ridge and the East Siberian continental margin. With the aim of determining the origin of freshwater in the halocline, fractions of river water and sea-ice meltwater in the upper 150 m were quantified by a combination of salinity and δ¹⁸O in the Eurasian Basin. Two methods, applying the preformed phosphate concentration (PO^*) and the nitrate-to-phosphate ratio (N/P), were compared to further differentiate the marine fraction into Atlantic and Pacific-derived contributions. While PO^*-based assessments systematically underestimate the contribution of Pacific-derived waters, N/P-based calculations overestimate Pacific-derived waters within the Transpolar Drift due to denitrification in bottom sediments at the Laptev Sea continental margin.Within the Eurasian Basin a west to east oriented front between net melting and production of sea-ice is observed. Outside the Atlantic regime dominated by net sea-ice melting, a pronounced layer influenced by brines released during sea-ice formation is present at about 30–50 m water depth with a maximum over the Lomonosov Ridge. The geographically distinct definition of this maximum demonstrates the rapid release and transport of signals from the shelf regions in discrete pulses within the Transpolar Drift.The ratio of sea-ice derived brine influence and river water is roughly constant within each layer of the Arctic Ocean halocline. The correlation between brine influence and river water reveals two clusters that can be assigned to the two main mechanisms of sea-ice formation within the Arctic Ocean. Over the open ocean or in polynyas at the continental slope where relatively small amounts of river water are found, sea-ice formation results in a linear correlation between brine influence and river water at salinities of about 32–34. In coastal polynyas in the shallow regions of the Laptev Sea and southern Kara Sea, sea-ice formation transports river water into the shelf’s bottom layer due to the close proximity to the river mouths. This process therefore results in waters that form a second linear correlation between brine influence and river water at salinities of about 30–32. Our study indicates which layers of the Arctic Ocean halocline are primarily influenced by sea-ice formation in coastal polynyas and which layers are primarily influenced by sea-ice formation over the open ocean. Accordingly we use the ratio of sea-ice derived brine influence and river water to link the maximum in brine influence within the Transpolar Drift with a pulse of shelf waters from the Laptev Sea that was likely released in summer 2005.  相似文献   

Impact of the Doha outcome on surplus emission allowances and their effect on developed country emissions     

Claudine M. Chen  Johannes Gütschow  Marion Vieweg  Kirsten Macey  Michiel Schaeffer 《Climatic change》2013,120(4):845-857

The outcome from the December 2012 climate negotiations in Doha has clarified the rules regarding surplus units for the Kyoto Protocol. We summarize these new rules and estimate the resulting effective emissions during the second commitment period using our unit trade model. Other options to deal with surplus emission allowances are employed as benchmarks to assess the Doha outcome. The effective emissions for developed countries as a group under the Doha outcome could be 10–11 % below 1990 levels or 4–5 % points below business-as-usual levels for the second commitment period if we assume that non-Kyoto Protocol countries domestically achieve their targets. However, if mechanisms exist where non-Kyoto Protocol countries can trade units, their emissions could increase and effective emissions for developed countries could be 7–8 % below 1990 levels. In this low-ambition situation we find the main impact of the Doha surplus rules to be the introduction of the historical cap on emissions allowances. Without the effect of the cap, the Doha outcome allows the Parties to the second commitment period to emit at business-as-usual levels until 2020, while still leaving surplus units at the end of the second commitment period.  相似文献   

Petrography,Sr-isotope geochemistry and geochronology of the Nxau Nxau kimberlites,north-west Botswana     

Farr  Henrietta  Phillips  David  Maas  Roland  de Wit  Michiel 《Mineralogy and Petrology》2018,112(2):625-638

The Nxau Nxau kimberlites in northwest Botswana belong to the Xaudum kimberlite province that also includes the Sikereti, Kaudom and Gura kimberlite clusters in north-east Namibia. The Nxau Nxau kimberlites lie on the southernmost extension of the Congo Craton, which incorporates part of the Damara Orogenic Belt on its margin. The Xaudum kimberlite province is geographically isolated from other known clusters but occurs within the limits of the NW-SE oriented, Karoo-aged Okavango Dyke Swarm and near NE-SW faults interpreted as the early stages of the East African Rift System. Petrographic, geochronological and isotopic studies were undertaken to characterise the nature of these kimberlites and the timing of their emplacement. The Nxau Nxau kimberlites exhibit groundmass textures, mineral phases and Sr-isotope compositions (⁸⁷Sr/⁸⁶Sr_i of 0.7036 ± 0.0002; 2σ) that are characteristic of archetypal (Group I) kimberlites. U-Pb perovskite, ⁴⁰Ar/³⁹Ar phlogopite and Rb-Sr phlogopite ages indicate that the kimberlites were emplaced in the Cretaceous, with perovskite from four samples yielding a preferred weighted average U-Pb age of 84 ± 4 Ma (2σ). This age is typical of many kimberlites in southern Africa, indicating that the Xaudum occurrences form part of this widespread Late Cretaceous kimberlite magmatic province. This time marks a significant period of tectonic stress reorganisation that could have provided the trigger for kimberlite magmatism. In this regard, the Nxau Nxau kimberlites may form part of a NE-SW oriented trend such as the Lucapa corridor, with implications for further undiscovered kimberlites along this corridor.

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Assessment of marine debris on the Belgian Continental Shelf   总被引：2，自引：0，他引：2  

Lisbeth Van Cauwenberghe  Michiel Claessens  Michiel B. Vandegehuchte  Jan Mees  Colin R. Janssen 《Marine pollution bulletin》2013

A comprehensive assessment of marine litter in three environmental compartments of Belgian coastal waters was performed. Abundance, weight and composition of marine debris, including microplastics, was assessed by performing beach, sea surface and seafloor monitoring campaigns during two consecutive years. Plastic items were the dominant type of macrodebris recorded: over 95% of debris present in the three sampled marine compartments were plastic. In general, concentrations of macrodebris were quite high. Especially the number of beached debris reached very high levels: on average 6429 ± 6767 items per 100 m were recorded. Microplastic concentrations were determined to assess overall abundance in the different marine compartments of the Belgian Continental Shelf. In terms of weight, macrodebris still dominates the pollution of beaches, but in the water column and in the seafloor microplastics appear to be of higher importance: here, microplastic weight is approximately 100 times and 400 times higher, respectively, than macrodebris weight.  相似文献   

SPICES: spectro-polarimetric imaging and characterization of exoplanetary systems     

Anthony Boccaletti  Jean Schneider  Wes Traub  Pierre-Olivier Lagage  Daphne Stam  Raffaele Gratton  John Trauger  Kerri Cahoy  Frans Snik  Pierre Baudoz  Raphael Galicher  Jean-Michel Reess  Dimitri Mawet  Jean-Charles Augereau  Jenny Patience  Marc Kuchner  Mark Wyatt  Eric Pantin  Anne-Lise Maire  Christophe Vérinaud  Samuel Ronayette  Didier Dubreuil  Michiel Min  Michiel Rodenhuis  Dino Mesa  Russ Belikov  Olivier Guyon  Motohide Tamura  Naoshi Murakami  Ingrid Mary Beerer 《Experimental Astronomy》2012,34(2):355-384

SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a five-year M-class mission proposed to ESA Cosmic Vision. Its purpose is to image and characterize long-period extrasolar planets and circumstellar disks in the visible (450?C900 nm) at a spectral resolution of about 40 using both spectroscopy and polarimetry. By 2020/2022, present and near-term instruments will have found several tens of planets that SPICES will be able to observe and study in detail. Equipped with a 1.5 m telescope, SPICES can preferentially access exoplanets located at several AUs (0.5?C10?AU) from nearby stars (<25 pc) with masses ranging from a few Jupiter masses to Super Earths (??2 Earth radii, ??10 M_??) as well as circumstellar disks as faint as a few times the zodiacal light in the Solar System.  相似文献   

Percolation and Particle Transport in the Unsaturated Zone of a Karst Aquifer   总被引：14，自引：0，他引：14  

by Michiel Pronk  Nico Goldscheider  Jakob Zopfi  and François Zwahlen 《Ground water》2009,47(3):361-369

Recharge and contamination of karst aquifers often occur via the unsaturated zone, but the functioning of this zone has not yet been fully understood. Therefore, irrigation and tracer experiments, along with monitoring of rainfall events, were used to examine water percolation and the transport of solutes, particles, and fecal bacteria between the land surface and a water outlet into a shallow cave. Monitored parameters included discharge, electrical conductivity, temperature, organic carbon, turbidity, particle-size distribution (PSD), fecal indicator bacteria, chloride, bromide, and uranine. Percolation following rainfall or irrigation can be subdivided into a lag phase (no response at the outlet), a piston-flow phase (release of epikarst storage water by pressure transfer), and a mixed-flow phase (increasing contribution of freshly infiltrated water), starting between 20 min and a few hours after the start of recharge event. Concerning particle and bacteria transport, results demonstrate that (1) a first turbidity signal occurs during increasing discharge due to remobilization of particles from fractures (pulse-through turbidity); (2) a second turbidity signal is caused by direct particle transfer from the soil (flow-through turbidity), often accompanied by high levels of fecal indicator bacteria, up to 17,000 Escherichia coli /100 mL; and (3) PSD allows differentiation between the two types of turbidity. A relative increase of fine particles (0.9 to 1.5 μm) coincides with microbial contamination. These findings help quantify water storage and percolation in the epikarst and better understand contaminant transport and attenuation. The use of PSD as "early-warning parameter" for microbial contamination in karst water is confirmed.  相似文献   

NMR Imaging of Fluid Exchange between Macropores and Matrix in Eogenetic Karst     

by Lee J. Florea  Kevin J. Cunningham  and Stephen Altobelli 《Ground water》2009,47(3):382-390

Sequential time-step images acquired using nuclear magnetic resonance (NMR) show the displacement of deuterated water (D₂O) by fresh water within two limestone samples characterized by a porous and permeable limestone matrix of peloids and ooids. These samples were selected because they have a macropore system representative of some parts of the eogenetic karst limestone of the Biscayne Aquifer in southeastern Florida. The macroporosity, created by the trace fossil Ophiomorpha , is principally well connected and of centimeter scale. These macropores occur in broadly continuous stratiform zones that create preferential flow layers within the hydrogeologic units of the Biscayne. This arrangement of porosity is important because in coastal areas, it could produce a preferential pathway for salt water intrusion. Two experiments were conducted in which samples saturated with D₂O were placed in acrylic chambers filled with fresh water and examined with NMR. Results reveal a substantial flux of fresh water into the matrix porosity with a simultaneous loss of D₂O. Specifically, we measured rates upward of 0.001 mL/h/g of sample in static conditions, and perhaps as great as 0.07 mL/h/g of sample when fresh water continuously flows past a sample at velocities less than those found within stressed areas of the Biscayne. These experiments illustrate how fresh water and D₂O, with different chemical properties, migrate within one type of matrix porosity found in the Biscayne. Furthermore, these experiments are a comparative exercise in the displacement of sea water by fresh water in the matrix of a coastal, karst aquifer since D₂O has a greater density than fresh water.  相似文献