芥川龙之介《水虎》三元比较研究

芥川龙之介的《水虎》与果戈理的《狂人日记》、鲁迅的《狂人日记》均采用了现实主义与象征主义相结合的创作方法，一针见血地揭露了社会制度的黑暗与腐朽。但他们在创作方法上使用的象征主义和对社会现实揭露的广度与深度不完全相同，主人公的思想高度更是各不相同。作品创作的背景、历史条件，作者的思想高度、性格特点和创作风格是造成这些差别的根源。     

电感耦合等离子体质谱法测定灌木枝叶中微量元素的样品预处理方法研究

利用电感耦合等离子体质谱法(ICP-MS)测定植物样品中微量元素的关键技术是消除植物样品的有机基体效应,本文通过预处理方法中的酸消解体系、称样量和消解方式消除其影响。以国家标准物质灌木枝叶组合样(GBW07603)为材料进行研究,对比分析了硝酸-过氧化氢、硝酸-氢氟酸、硝酸-氢氟酸-过氧化氢3种酸溶体系的消解效果,以确定最佳酸溶体系,进而定量研究2种称样量(50 mg和100 mg)和3种消解方式(密封高压二次消解、密封高压一次消解、微波消解)的消解效果,并以In作为内标采用ICP-MS测定微量元素含量。结果表明:硝酸-氢氟酸-过氧化氢酸溶体系的消解效果最好;50 mg的测定值更接近于参考值;微波消解法的测定值明显偏低,而密封高压二次消解法是灌木枝叶样品预处理的有效方法。     

Horizontal and vertical zones of influence for root systems of four Mojave Desert shrubs

Horizontal and vertical zones of influence for root systems of four Mojave Desert shrubs were characterized using ³²P as a nutrient tracer. Larrea tridentata's horizontal zone of influence was sparse near the plant's stem base, with a maximum probability of accessing ³²P (P_max) of 41%. However, its horizontal zone of influence extended beyond 5 m, and the distance from the stem base at which the probability of accessing ³²P was half P_max (L₅₀3 m) was significantly greater than the other three shrubs. Ambrosia dumosa's zone of influence was dense near the plant's stem base (P_max78%), but was rare at distances >2 m (L₅₀1 m). Zones of influence for Lycium andersonii and Lycium pallidum were intermediate between those of L. tridentata and A. dumosa. For vertical zones of influence, L. tridentata was more likely to obtain ³²P from 5 m soil depths than A. dumosa, but L. pallidum was not significantly different from either A. dumosa or L. tridentata. Horizontal zones of influence did not change with treatments that altered soil water and nitrogen availability, but vertical zones of influence increased with a flood irrigation treatment that increased water availability to 5 m soil depth. These differences among species likely reflect compromises between their shoot growth strategies and their need to acquire spatially and temporally limited soil resources, especially through competitive interactions.     

Dynamic Changes of the Bush Encroachment in Low Altitude Area of Ethiopia

Bush encroachment is widely distributed in arid and semi-arid regions, and it has a serious impact on livestock production, especially in Africa where livestock is a primary source for the livelihoods of many people. In this study, methods of supervised classification and decision tree classification, and indexes of a land use change significance index (Ci) and a single land use dynamic degree, were applied to remote sensing imagery of Ethiopia for 1986-2016. The results show the dynamic characteristics of grassland bush encroachment in low altitude areas (pastures <1500 m above sea level) of Ethiopia in the 30 year period studied. The results revealed several interesting features of this phenomenon. (1) The area of bush encroachment showed an increasing trend, with a maximum of 3.74×10³ km² in 2003, which represented 68.97% of the total area, and declined slightly from 2003~2016. (2) Among classification types, the area of severe shrub grassland was the largest, accounting for 28.36-49.10% of the total area, while the area of moderate bush encroachment accounted for 9.77-16.68%, and slight bush encroachment accounted for 5.52-7.57%. (3) The expansion rate of shrubby grassland was 0.74% for the 30 year period, while the average annual expansion rate was 2.16% for the 8 years from 1995-2003. (4) Forest land and grassland were the two main land use types of shrub grassland transformation in low altitude areas and bush encroachment changed large amounts of forest land into grassland due to shrub grassland management. The results of this study provide basic data for revealing the impacts of development processes on subsequent bush encroachment and can inform better management for the sustainable development of grasslands in low altitude systems.     

距离式森林活力评价的研究与实践

森林活力是森林生长、更新的能力,其主要受垂直结构功能和水平景观格局的影响和制约。通过与原生林的比较,揭示与原生林群落结构或功能的差距可以一定程度上反映森林的活力水平。目前,中国基于“距离式”思想的森林活力评价方法仍局限于群落尺度,而新西兰学者则提出了结合多尺度、多要素且简单实用的森林活力评价方法。通过典型群落样方调查和森林斑块格局分析,获取云南石林喀斯特公园森林恢复更新数据和斑块格局,对照目标群落,依据6个评价项目与指标,评价了公园4种主要森林植被恢复的森林活力,结果显示：依滇青冈林（Form．Cyclobcdanopsis glaucoides）,云南木樨榄-滇青冈林（Form．Olea yunnanensis—Cyclobcdanopsis glaucoide）,团花新木姜子林（Form．Olea yunnanensis）,云南松林（Form．Pinus yunnanensis）的顺序森林活力降低;影响公园森林活力最主要的因素是森林斑块的抗干扰能力和物种源水平。     

Use of camera traps to determine dispersal of tigers in semi-arid landscape,western India

Dispersal is a life history trait that plays a key role in population dynamics. We used camera traps to estimate the distance male and female tigers (Panthera tigris) dispersed from Ranthambhore Tiger Reserve (RTR) in semi-arid habitats of western India from 2003 to 2010. We deployed camera traps whenever tiger tracks were found in places adjacent to protected areas where tigers had not been recently reported. We identified tigers by matching strip patterns by using their photographs with the database of camera-trapped tigers of RTR at the Wildlife Institute of India, Dehradun. We determined the aerial distance (straight line) between the last location of photo-capture in the natal area (in RTR) and the location of the most recent photo-capture. One female and three male tigers that dispersed from RTR were identified from photographs. The longest distance dispersed by a tiger was 148.4 km, and the average dispersed distance was 124.2 ± 23.7 km (n = 3) for male tigers and 78.4 km for the female tiger. The minimum age of the male tigers when they dispersed was 24 months. These data are important for making conservation and management decisions for restoration of potential connectivity between landscapes.     

Modeling unusual eruptive behavior of Mt. Etna,Italy, by means of event bush

One of the best-studied volcanoes of the world, Mt. Etna in Sicily, repeatedly exhibits eruptive scenarios that depart from the behavior commonly considered typical for this volcano. Episodes of intense explosive activity, pyroclastic flows, dome growth and cone collapse pose a variety of previously underestimated threats to human lives in the summit area of the volcano. However, retrospective analysis of these events shows that they were likely caused by the same very sets of premises and starting conditions as “normal” eruptions, yet combined in an unexpected, probably unique, way. To cope with such unexpected consequences, we involve an approach of artificial intelligence developed specially for needs of the geosciences, the event bush. Scenarios inferred from the event bush fit the observed ones and allow to foresee other low-probability events that may occur at the volcano. Application of the event bush provides a more impartial vision of volcanic phenomena and may serve as an intermediary between expert knowledge and numerical assessment, e.g., by means of Bayesian Belief Networks.     

植被覆盖、放牧和季节对牧草种类组成和生物量的影响:以埃塞俄比亚南部Yabello牧场为例

Yabello牧场是埃塞俄比亚博拉纳的一个半干旱地区的牧场,目前面临着草场退化的严重挑战。植被覆盖的变化、过度放牧和季节性变化极大地影响了Yabello牧场的牧草组成和生物量。本文评估了植被覆盖、放牧和季节对Yabello牧场的牧草组成和生物量的影响。首先采用1 m×1 m的随机样方进行实验,根据植被覆盖类型和放牧变化选择样点,并对季节影响进行评估。使用SAS统计软件和MicrosoftExcel分析牧草组成、牧草高度和质量数据。本研究总共记录了26种草种,其中Chloris roxburghiana, Chrysopogon aucheri和Chrysopogon aucheri草种均表现出最高的平均单种覆盖高度和生物量产量。因此,建议将这些草种用于研究区域退化草地的恢复。研究结果还表明,植被覆盖类型、放牧和季节变化是决定牧草种类组成、牧草高度和生物量产量的关键因素。最后,研究结论还认为控制灌木丛植被并平衡放牧水平的可持续管理对于该地区的可持续牧草生产和生物多样性保护至关重要。     

Analysis of land degradation processes on a tiger bush plateau in South West Niger using MODIS and LANDSAT TM/ETM+ data

Remote sensing digital image analysis has been applied to monitor land clearing and degradation processes on a plateau covered by tiger bush near Niamey in South West Niger, where signs of severe landscape degradation due to fuelwood supply have been observed in the last decades. A MODIS NDVI dataset (2000–2015) and five LANDSAT images (1986–2012) were used to identify spatial and temporal dynamics and to emphasize areas of greater degradation. The study indicates that the land clearing found by previous investigations in the second part of the 20^th century is still ongoing, with a decreasing trend of MODIS NDVI values recorded in the period 2000–2015. This trend appeared to be linked to an increase in bare soil areas that was demonstrated by analysis of LANDSAT SAVI images. The investigation also indicated that rates of degradation are stronger in more deteriorated areas like those located nearer Niamey; degradation patterns also tend to increase from the inner areas to the edges of the plateau. These results attest to the urgency to develop effective environmental preservation policies and find alternative solutions for domestic energy supply.     

北京地区垃圾填埋对地下水的污染及垃圾填埋场选址分区

本文介绍了北京市生活垃圾处理现状及由于垃圾填埋而引起的地下水污染问题。以北京西郊南部北天堂垃圾填埋场的污染状况为例进行研究,通过建立数学模型来模拟污染物在地下水中的运移及补救效果,对污染控制进行了模拟,分析及提出相关建议;并对北京市生活垃级填埋场遗址进行了分区。