To understand the characteristics of the nebkhas in barchan interdune areas, isolated barchan dunes at the southeast margin of the Badain Jaran Desert in China and Nitraria tangutorun nebkhas in the interdune areas were selected, and the morphometric parameters, spatial patterns, and granulometric characteristics of the nebkhas in various interdune zones were compared. According to the locations relative to barchan dunes, the interdune areas were divided into three zones: the windward interdune zone (Zw), the leeward interdune zone (Zl), and the horn interdune zone (Zh). The zone that is proximal to barchan dunes and has never been disturbed by barchan dunes was also selected (Zi). The morphometric parameters were measured through a satellite image and field investigation. The population density and spatial patterns were analyzed using the satellite image, and surface sediment samples of the nebkhas and barchan dunes were collected for grain size analysis. The morphometric parameters of Nitraria tangutorun nebkhas in the interdune zones differ significantly. The nebkhas in Zh are larger than those observed in the other zones, and the nebkhas are the smallest in Zl. In all of the zones, the long-axis orientation of the nebkhas is perpendicular to the prevailing wind direction. The population density of the nebkhas in Zw is relatively higher, whereas the density in Zh and Zl becomes obviously lower. The spatial distribution of nebkhas in all of the zones can be categorized as a dispersed pattern. The sediments of the nebkhas are coarsest in Zh and finest in Zl. In addition, the sediments of the nebkhas in all of the zones are finer than those of barchan dunes. The amount of sand captured by the nebkhas in the interdune areas is approximately 20% of the volume of barchan dunes. The variations of the nebkhas' sizes, spatial pattern and sediment are subjected to migration, flow field and sand transport of barchan dunes and sand accumulation with plant growth in the interdune areas, which suggest complex mutual interactions between barchan dunes and the nebkhas in the interdune areas.

The Alxa Plateau in north China is characterized by frequent sand dust storm activity, desertification, various blown sand hazards and extensive sand dunes. Three of China's major sand deserts, the Badain Jaran (BJ), Tengger and Ulan Buh (UB), are distributed in this region. The BJ desert lies to the northwest and is separated from the other two deserts by mountains Yabrai and Alateng. However, the dominant northwest wind could transport sand from the BJ to the other two deserts through several corridors. Locating the sand source for these deserts is fundamental in understanding the formation and evolution of the aeolian landforms. It has been proposed that the sand in the Tengger desert is from the BJ desert. However, evidence supporting the hypothesis is still limited. To estimate the sand contribution of the BJ to the Tengger desert, we measured wind speeds at a 2 m height above the ground for the period from November 2010 to December 2011. We then calculated the amount of sand transport and observed the speed of dune migration in the junction part of the two deserts. Sand-transporting winds (>= 6.0 m s(-1)) occurred mostly in spring and winter, and accounted for 16.4% of the total of the year. The prevailing wind directions were NW, WNW and NNW, and were occupied 61.9% of the total frequency of sand-transporting winds. The frequencies of winds decreased with increasing wind speed, and strong wind frequencies (>= 17.0 m s(-1)) were 5.3% of the sand-transporting winds. In comparison to adjacent areas, the drift potential in the corridor was several times higher, indicating an obvious effect of narrowing. During the period of observation, 752 sand-transporting events occurred with durations from 10 to 1940 mm (32 h). In the corridor, the sand transport flux was 372 tons m(-1) yr(-1), an order of magnitude larger than previous estimation, and the annual total amount of sand transported through the corridor was over 5 million tons, indicating a substantial sand supply from the BJ to the Tengger desert. Sand transport in spring and winter accounted for 99.8% of annual total. The amount of sand transported by a single sand-transporting event varied greatly, up to five orders of magnitude. (C) 2014 Elsevier B.V. All rights reserved.

随着甘肃经济水平的日益提高,人们的消费水平也随着逐渐提高。在拥有了足够的经济实力背景下,越来越多的人拥有手机,这其中又特别是大学生,手机已经成为了他们沟通、生活中不可缺少的通信工具。手机在大学生群体中已相当普及,大学生群体作为新事物的接受者和创造者,极具消费潜力,是各大通信运营商竞相抢夺的市场,通过对兰州市十所高校的1330名大学生进行问卷调查,根据对调研结果的分析,正确把握运营商在兰州市大学生通信市场占有情况,详细了解兰州市大学生的手机通信消费特点,进而为我国通信运营商制定相关政策提供依据。

Environmental audit can effectively monitor and evaluate the use of funds and governance effectiveness in the process of heavy metal pollution governance in Xiangjiang river basin.Through environmental management performance audit,pollution control project management audits,pollution control project funds management audits,sewage treatment fees and sewage charges audit,pollution effects audit,heavy metal pollution governance in Xiangjiang river basin can be implemented by macro-level monitoring and evaluation mechanisms,meso-level coordination and regulation mechanism,and micro-level monitoring and early warning mechanisms.We should divide environmental audit area,strengthen economic responsibility audit,carry out special audit investigation,and introduce trails audit to full play the role of environmental audit immunity to heavy metal pollution in Xiangjiang river basin.

In this article, natural factors in the farming-pastoral ecotone that might have influenced the blown sand hazards in Beijing in 2000 are analyzed. In the farming-pastoral ecotone, blown sand activities took place primarily in springtime, during which 39.8 percent of the annual frequency of erosive winds above threshold occurred. The prevailing directions of the erosive winds were NNW, NW, NWW, and N, with frequencies of 47, 20, 13, and 9 percent respectively. Sand entrainment and dust emission are influenced by erosive wind frequency, soil moisture, and land use and cover change. Favorable wind characteristics and a lasting drought in 1999 and 2000 may have produced ideal conditions for land surface desiccation, vegetation degradation, and land surface mobility and the occurrence of intense sand- and dust storms in Beijing.

Above-ground parts of the plant are key components that alter the wind flow and affect the movement of blown sand.The volume of dune body and sediment transport rate may be used to measure the capacity of plant for trapping blown sand,which is influenced by some factors such as plant morphology and structure,roughness concentration,community collocation and so on.Under the same circumstance,different plants may have different capacities for trapping blown sand due to differential crown morphology,flexibility of branch and leaf area.In different phonological phases of the same plant,the factors like crown morphology,flexibility of branch,leaf area and the resulting distribution pattern of aboveground biomass change significantly.There are several future research directions of capacity of plant for trapping blown sand.(1) How to determine and divide the flexibility levels of plant branch,and to develop evaluation indexes and system of capacity of plant for trapping blown sand;(2) how to make certain the critical roughness concentration of plant community for trapping blown sand;(3) how to enhance the diversity of configuration models when community roughness concentration reaches critical roughness concentration,and find the effectiveness and coordination among roughness concentration,community collocation(when distance between rows and hills changes) and utility maximization to contribute to the current practice of ecological construction.

Soil moisture and particle size are important for the vegetation and evolvement of nabkhas.Based on the measurement of particle size and soil moisture in April and July of typical nebkhas in the Mu Us Sandland,the paper reveals the spatial-temporal characteristics of soil moisture at different position of the nebkhas,and the distribution law of particle size:Due to the measurement that was made 1 hour after the rainfall in July,soil moisture fell with the depth in 0-10 cm soil layer of interdune and dunetop.Soil layer of interdune from 0 cm to 70 cm was influenced by environmental factors such as vegetation,rainfall and solar radiation.At the dunetop,the topsoil was covered by old wattle of shrub,which restrained the evaporation of soil moisture in 0-30 cm soil layer,increased roughness,reduced wind speed and sand blown activity,and supplied a method to maintain water balance;in 30-80 cm soil layer,soil moisture was richer in July than in April,because July was in rainy season,rainwater infiltration lead to rich soil water.Wind condition,vegetation and dune activity decided the soil moisture change at different position.Root distribution and vegetation decided soil water dynamic and the depth that inflexion occurred.The particle size characteristic was similar that fine sand content was the highest at windward,dunttop,leeward and interdune.In vertical structure,fine sand and very fine sand were high and silt was latter.Clay,medium sand,sand content changed little with the depth,very fine sand and fine sand content changed a lot with the depth.

Based on the facts that geostationary meteorological satellites have a few channels and most of them are in the middle and thermal infrared region,the linear spectral mixture model(LSMM) was applied to enhance dust information based on automatic selection of endmembers according to the accumulation histogram of related channels.Then a hybrid model for deriving dust pixels from FY-2C/2D data was proposed.The results show that the dust information can be enhanced through LSMM and the endmembers can be derived based on the accumulation histogram of the original images automatically.The pseudo dust pixels can be eliminated following two criterions: 1) the difference of brightness temperatures in channel 11 μm and channel 12 μm is negative;2) dust pixels have greater difference between brightness temperatures in channel 3.7 μm and channel 11μm than other objects.FY-2C images were utilized to monitor a dust storm process from April 27 to April 28,2005 in northern China.The application indicates that the method obtained high accuracy and the transportation process of the dust storm was described quantitatively.

Plant morphology is important for shaping sand dune morphology.Based on the measurement of typical plants and dune morphology in the Mu Us Sandland,the paper quantificationally analyzes three kinds of plants,and then discusses their sand trapping capability.Correlative analysis of primary parameters shows that,the length and width of plants correspond with length and width of dunes apparently;dune height is slightly correlated to plant height,but there is no correlation between dune height and plant crown height;component L and plant height H have correlation,hut the correlation coefficient from high to low is that Stipa plareosa,Salix psammophila,Artemisia spherocephala;the dune volume is strongly correlated to the plant vol- ume,but the correlation coefficient from high to low is that Stipa plareosa,Salix psammophila,Artemisia spherocephala.The results prove that the capability of sand trapping is that Artemisia spherocephala is higher than Stipa plareosa,Stipa plareosa is higher than Salix psammophila.

Soil clods caused by plowing are the main roughness elements for wind erosion control in cropland of arid and semiarid regions,especially while no crop straw left on soil surface in fallow.However,the following operation of harrowing and milling destroy soil clods,which make its benefit of wind erosion control disappeared.Through field test,the size and cover fraction of soil clods under three kinds of soil surface,including just after plowing,harrowing,and milling respectively,were observed.Roughness of soil surface,decrement of wind velocities in the height of 0～3 m,aerodynamic roughness and friction velocity were calculated through analyzing soil surface fluctuation and wind velocity data.The results indicated the length,width,height of soil clods were all larger than 15 cm,and its cover fraction reached 27.67% after plowing operation,while after harrowing and milling operation the size and cover fraction of soil clods decreased significantly,especially after milling operation the cover fraction of soil clods was only 2.13%.Compared with after plowing,soil surface roughness decreased by 34%～64% after harrowing and by more than 90% after milling, and wind velocities in the height of 0～0.5 m increased significantly.Aerodynamic roughness was reduced from 1.1 cm to 0.05 cm after plowing surface of soil was milled,which made its benefits on wind erosion control obviously decreased.So choosing the time of plowing,harrowing and milling reasonably was important for wind erosion control on cropland of arid and semiarid regions.

There exists a long tradition of the poor relief in Britain. The seventeenth century witnessed the gradual evolution of the workhouse. After 1834, “indoor relief” had become the center of the New Poor Law system .Following two principles of “less eligibility ”and the “workhouse test ”, the Poor Law commissioners intended to make the workhouse a deterrent institution. By this way they could encourage the poor to be self-reliant so as to reduce the relief expenditure. The workhouse played a great part in the shaping of the Welfare State and the Social Security in British history. There are many disputes on the evaluation of the workhouse. The paper wants to analyse the system and hopes that scholars will pay more attention to this field.

Vegetation is a fundamental component of urban environment and its abundance is determinant of urban climate and urban ground energy fluxes. Based on the radiometric normalization of multitemporal ASTER imageries, the objectives of this study are: firstly, to estimate the vegetation abundance based on linear spectral mixture model (LSMM), and to compare it with NDVI and SDVI; secondly, to analyze the spatial distribution patterns of urban vegetation abundance in different seasons combined with some landscape metrics. The result indicates that both the vegetation abundance estimation based on LSMM and SDVI can reach high accuracy; however, NDVI is not a robust parameter for vegetation abundance estimation because there is significant non-linear effect between NDVI and vegetation abundance. This study reveals that the landscape characteristics of vegetation abundance is most complicated in summer, with spring and autumn less complicated and simplest in winter. This provides valuable information for urban vegetation abundance estimation and its seasonal change monitoring using remote sensing data.

从17世纪开始,济贫院在英国逐步发展起来;1834年后,院内救济成为新济贫法体系的核心。济贫法委员会希望通过济贫院的威慑作用,促使贫民自力更生,减少济贫开支。济贫院遵循“劣等处置”和“济贫院检验”两个原则,院内的生活比较悲惨,被大众冠以穷人的“巴士底狱”,到19世纪70年代后才逐步得到改善。济贫院制度在英国社会保障制度和福利国家形成过程中起到不可忽视的作用。

The field investigation was undertaken to determin the characteristics of Salix psammophila plant morphdogy and airflow structure of single-line S. psammophila on the southern edge of the Mu Su sandland. The results showed that artificially cultivated single-line S. psammophila could accumulate sand because the plant decreased the windward and leeward wind velocity. There was a significant correlation (R = 0.696) between accumulated sand volume (V 2) and plant volume (V 1). The wind velocity was 6 m/s at a 4 m height of single-line S. psammophilahedge row. The wind velocity decreased at 3 H windward and increased at 2 H to windward. The wind velocity then steeply decreased to leeward and reached its lowest value at 1 H to leeward and gradually recovered to the open field velocity. The protection distance of the single-line S. psammophila was about 17 H′ and the effective protection distance was about 13 H′. Single-line S. psammophila had few effects on the wind velocity when the wind was above the plant height.