基于GIS探讨人类活动和坡度对藏羚生境的影响

以3S技术为手段，研究了藏羚在青海最主要分布区曲麻莱、治多和可可西里境内藏羚生境状况及其坡度、道路、和居民点对藏羚生境的影响。通过野外考察基本掌握了藏羚的生境的基本特征，取得了考察路线附近区域内藏羚分布的GPS数据及其具有对应的数量、地形地貌、生境类型、人类活动状况等属性数据的藏羚分布点图层。对研究地区LANDSAT TM / ETM+ 5（红）、4（绿）、3（蓝）波段组合影像进行非监督分类，共分出水体和裸岩、沼泽地、沙地、砾石地、低草地、中草地和高草地7种生境类型，将藏羚生境适宜等级划分为不适宜、较差、适宜和非常适宜，其中适宜等级和非常适宜等级的生境类型为藏羚适宜的生境。 首先，将藏羚分布点图层分别和遥感影像假彩色合成图像、坡度图层、道路图层、居民点图层进行叠加分析、距离查询等分析了遥感影像非监督分类的判图依据，设立了坡度、道路、居民点对藏羚生境影响强度的评价原则。然后，通过对研究地区遥感影像进行非监督分类分析研究了藏羚不同适宜程度的生境面积。通过坡度分析和地图查询分析研究了坡度对藏羚生境的影响。通过缓冲区分析研究了道路和居民点对藏羚生境的影响。最后将坡度、道路和居民点三个因素结合起来通过地图综合查询分析研究了这三个因素对藏羚生境的综合影响，并给出了研究地区藏羚不同适宜等级的生境面积。 主要的研究结果和结论如下： 1、从不同类型生境在研究地区中所占比例的趋势上看，治多地区和曲麻莱地区的植被要明显优于可可西里地区，这与整个研究地区从西北到东南地势逐渐降低、水热条件逐渐变好的趋势相一致，至少可以说，从食物条件来看，治多地区和曲麻莱地区比可可西里地区更适于藏羚的栖息。 在曲麻莱地区藏羚的潜在生境面积共26861 km2，占该地区总面积的69%；在治多地区藏羚的潜在生境面积共21617 km2，占该地区总面积的68%；在可可西里地区藏羚的潜在生境面积共26398 km2，占该地区总面积的54%。 2、根据藏羚分布点图层与坡度分析图层的地图查询分析，把藏羚的生境按坡度分为2类，坡度小于等于30度时为适宜生境，坡度大于30度时为不适宜生境。将研究地区坡度栅格图像（grid文件）和非监督分类结果栅格图像（grid文件）进行地图查询分析，结果表明，在整个研究地区坡度大于30度的生境面积所占的比例不到总面积的3%，坡度影响下研究地区藏羚适宜栖息的生境面积变化不大。考虑到坡度的影响，曲麻莱、治多和可可西里适合藏羚栖息的面积分别为26663 km2（68%）、21187 km2（66%）和26350 km2（54%）。 3、根据最近原则连接藏羚分布点图层与道路图层空间数据，通过Distance综合查询分析，把道路对藏羚的影响程度划分为4个等级：距离道路0－1000m，强烈影响；距离道路1000－2000m，中度影响；距离道路2000－3000m，轻度影响；距离道3000m以外，无影响。然后在ArcView GIS 3.2a软件环境的支持下对研究地区的道路图层分别做距离道路为1000m、2000m和3000m的缓冲区分析研究，则曲麻莱、治多和可可西里地区藏羚生境受道路累计影响的面积及其分别占各研究地区总面积的比例分别为20215 km2（51.80%）、19480 km2（61%）和4437 km2（9 %）。考虑道路对藏羚生境的影响，在治多和曲麻莱地区，由于道路的影响将使得藏羚生境大面积丧失，生境高度破碎化。 4、根据最近原则连接藏羚分布点图层与居民点图层空间数据，通过Distance综合查询分析，把居民点对藏羚的影响程度划分为4个等级：距离居民点0－3000m，强烈影响；距离居民点3000－6000m，中度影响；距离居民点6000－9000m，轻度影响；距离居民点9000m以外，无影响。然后在ArcView GIS 3.2a软件环境的支持下对研究地区的居民点图层分别做距离居民点距离为3000m、6000m和9000m的缓冲区分析。曲麻莱、治多和可可西里地区藏羚生境受居民点影响的面积及其分别占总面积的比例分别为11282 km2（29%）、15258 km2（48%）和3846 km2（8%）。从居民点对藏羚生境的影响看，由于居民点的影响使得治多和曲麻莱地区，尤其是治多地区，藏羚生境大面积丧失，生境高度破碎化。 5、人类活动（主要是道路和居民点）对藏羚生境适宜生境面积的影响是研究中主要的内容，鉴于道路和居民点对藏羚生境影响的评价原则分类方法一致，我们把道路和居民点对藏羚的影响程度合并为4个等级（距离道路0－1000m内或距离居民点0－3000m内，强烈影响；距离道路1000－2000m内或距离居民点3000－6000m内，中度影响；距离道路2000－3000m内或距离居民点6000－9000m内，轻度影响；距离道路3000m以外或距离居民点9000m以外，无影响，对道路和居民点相应距离的缓冲区分析图层进行合并等操作，测定曲麻莱、治多和可可西里地区藏羚生境受人类活动影响的面积及其占总面积的比例分别为21595 km2（55%）、22271 km2（70%）和4775 km2（10%）。 在治多和曲麻莱地区，由于人类活动的影响使得藏羚生境大面积丧失，生境高度破碎化，尤其是治多地区，影响面积达将近70%。在可可西里地区，10%的影响面积虽然不是太大，但是近几年来由于各种形式的旅游日趋升温，尤其是青藏铁路建设开通，将增加道路对藏羚生境的影响程度。人类活动影响在研究地区分布极不平均，在曲麻莱的中东部、治多的东部以及可可西里的109国道附近人类活动影响的强度较大，在这些地区藏羚的生存条件恶劣，甚至部分地区已经不适合藏羚栖息了。 6、最后，基于研究地区的坡度grid图层、非监督分类grid图层以及不同程度人类活动影响的grid图层，对不同坡度、道路和居民影响的生境面积进行综合查询分析。把人类活动对藏羚生境的影响强度重新划分为如下3个等级，A、短距离影响，距离道路1000m或距离居民点3000m范围内的影响，也就是人类活动的强烈影响；B、中距离影响，距离道路2000m或距离居民点6000m范围内的影响，也就是人类活动的强烈影响和中度影响之和；C、长距离影响，距离道路3000m或距离居民点9000m范围内的影响，也就是人类活动的强烈影响、中度影响和轻度影响的总和。曲麻莱、治多和可可西里研究地区中坡度小于等于30度并且人类活动长距离范围影响下藏羚适合栖息的生境面积及占相应研究地区总面积的比例为12597 km2（32%）、6117km2（19%）和23564km2（48%）。 在研究地区，治多地区人类活动对藏羚生境适宜性的影响最为严重，其次为曲麻莱地区，而可可西里地区的人类活动影响较小。尤其是治多地区和曲麻莱地区，当人类活动的影响最大距离时，治多地区藏羚适宜生境面积竟然不到总面积的1/5，曲麻莱地区不到1/3。这两地区人类活动主要集中在东部，导致治多东部地区和曲麻莱中东部地区几乎没有藏羚分布。于是，由于人类活动的影响，使得拥有良好生境条件的治多和曲麻莱地区适合藏羚栖息的生境却较少，而生境条件相对较差的可可西里地区反而拥有相对较多的适合藏羚栖息的生境。

化德群和土门群沉积岩碎屑锆石研究：对华北克拉通基底及元古宙盆地演化的指示意义

The Huade Group, consisting of low-grade and un-metamorphosed sedimentary rocks with no volcanic interlayer, is located at the northern margin of the North China craton and adjoining the south part of the Central Asian Orogenic Belt. It is east to the Paleo- to Meso-Proterozoic Bayan Obo and Zhaertai-Langshan rifts and northwest to the Paleo- to Neo-proterozoic Yanshan aulacogen, in which the typical Changcheng, Jixian and Qingbaikou systems are developed. The Huade Group are mainly composed of pebbly sandstones, sandstones, greywackes，shales，calc-silicate rocks and limestones, partly undergoing low-grade metamorphism and being changed to meta-sandstones, schists, phyllites, slates and crystalline limestones or marbles. The stratigraphic sequences show several cycles of deposition. Each of them developed coarse clastic rocks – interbedded fine clastic rocks and pelites from bottom upward or from coarse clastic rocks to interbedded fine clastic rocks and pelites to carbonate rocks. The Tumen Group outcrop sporadically around or west to the Tanlu faults in western Shandong. They are mainly composed of pebbly sandstones, sandstones, shales and limestones. This thesis deals with the characteristics of petrology, geochemistry and sedimentary of the Huade Group and the Tumen Group, and discusses the LA-ICP-MS and SIMS U-Pb ages, Hf isotope and trace element composition of the detrital zircons from 5 meta-sandstone samples of the Huade Group and 3 sandstone samples of the Tumen Group. The age populations of the detrital zircons from the Huade Group are mainly ~2.5 Ga and ~1.85 Ga, and there are also minor peaks at ~2.0 Ga, ~1.92 Ga and ~1.73 Ga. Most of the detrital zircon grains of 2.47-2.57 Ga and a few of 1.63-2.03 Ga have Hf crust model ages of 2.7-3.0 Ga, and most of the detrital zircon grains of 1.63-2.03 Ga have Hf crust model ages of 2.35-2.7 Ga, with a peak at 2.54 Ga. The main age peaks of the detrital zircons from the Tumen Group are ~2.5 Ga、~1.85 Ga, 1.57 Ga, 1.5 Ga, 1.33 Ga and 1.2 Ga. Different samples from the Tumen Group have distinct Hf isotopic characteristics. Detrital zircon grains of ~2.52 Ga from one sandstone sample have 2.7-3.2 Ga Hf crust model ages, whereas zircon grains of 1.73-2.02 Ga and 2.31-2.68 Ga from another sample have Hf crust model ages of 2.95-3.55 Ga. Detrital zircon grains of Mesoproterozoic ages have Paleoproterozoic (1.7-2.25 Ga) crust model ages. Through detailed analyses of the detrital zircons from the Huade and Tumen Group and comparison with those from the sedimentary rocks of similar sedimentary ages, the thesis mainly reaches the following conclusions: 1. The youngest age peaks of the detrital zircons of 1.73 Ga constrains the sedimentary time of the Huade Group from late Paleoproterozoic to Mesoproterozoic. 2. The age peaks of detrital zircons of the Huade Group correspond to the significant Precambrian tectonic-thermal events of the North China craton. The basement of the North China craton is the main provenance of the Huade Group, of which the intermediate to high grade metamorphic sedimentary rocks are dominant and provide mainly 1.85-1.92 Ga sediments. 3. The Huade basin belongs to the North China craton and it is suggested that the northern boundary of the North China craton should be north to the Huade basin. 4. The stratigraphic characteristics indicate the Huade Group formed in a stable shallow-hypabyssal sedimentary basin. The rock association and sedimentary time of the Huade Group are similar to those of the Banyan Obo Group and the Zhaertai Group, and they commonly constitute late Paleoproterozoic to Mesoproterozoic continental margin basins along the northern margin of the North China craton. 5. The continental margin basins would have initiated coeval with the Yanshan and Xiong’er aulacogens. 6. The ages of the detrital zircons from the Tumen Group and the Penglai Group at Shandong peninsula and the Yushulazi Group at south Liaoning are similar, so their sedimentary time is suggested to be Neoproterozoic，coeval with the Qingbaikou system. The detrital zircon ages of 1.0-1.2 Ga from the Tumen Group, the Penglai Group and the Yushulazi Group indicate that there have being 1.0-1.2 Ga magmatic activities at the eastern margin of the North China craton. 7. The U-Pb age populations of the detrital zircons from the late Paleoproterozoic to Neoproterozoic sedimentary rocks suggest that the main Precambrian tectonic-thermal events of the North China craton happened at ~2.5 Ga and ~1.85 Ga. But the events at 2.7 Ga and 1.2 Ga are also of great significance. Hf isotope characteristics indicate that the significant crust growth periods of the North China craton are 2.7-3.0 Ga and ~2.5 Ga.

中老年危机热线来电者的应激源与自杀危险性

Objective: Psychosocial crisis and psychiatric disorders are two stressors for suicide action. This study will explore the differences on demographic characteristics, severity of depression, and suicidality of middle-aged and elder crisis line callers under the influences of psychosocial crisis or psychiatric disorders or two simultaneously-mixed stressors, in order to develop effective intervention strategies for crisis line. Methods: Analysis data of 1,092 cases selected from national crisis line callers aged 45 and over who were assessed with “Suicide risk assessment” during the period from December, 2002 to December, 2008. The sample were divided into three groups of psychosocial crisis, mental health problems, and mixed-stressors of three types of general callers (48.2%, 32.3%, 19.5%), callers with current suicide ideation (43.7%, 33.0%, 23.3%) and callers attempted suicide 2 weeks prior to the call (33.6%, 42.3%, 24.1%) respectively according to the operators’ judgments of the callers’ claimed difficult situations and classification system of crisis line database. X2 test and Tukey-type and Multinomial Logistic Regression multiple comparison methods are applied to analysis the differences of the three groups. Results: In agreement with previous studies, more females (71.3%, X2=13.45, P<0.001), especially females influenced by relationship stressors (76.8%, X2=25.12, P<0.001) made the call for crisis. Among general callers, the check-out rates of Major Depression Episode of mixed-stressor callers (78.5%, P<0.001) and problem callers (68.7%, P<0.05) were significantly higher than that of crisis callers (57.1%). The check-out rates of suicide ideation of mixed-stressor callers (71.4%) were significantly higher than that in crisis callers (53.8%, P<0.001) and problem callers (60.9%, P<0.05). The check-out rates of prior suicide attempts of mixed-stressor (16.6%, P<0.05) and problem callers (18.5%, P<0.01) were significantly higher than that of crisis callers (9.8%). More than half of the mixed-stressor callers (51.8%) reported over 50% degree of hopelessness, which was significantly higher than that of crisis callers (35.6%, P<0.01) and problem callers (38.2%, P<0.05). Fewer crisis callers sought medical help than problem and mixed-stressor callers among three types of callers (X2=241.35, 146.56, 50.87; P<0.001). Compare to non-compound crisis callers, the proportion of minor, severe depression and prior depression diagnosis (14.0% vs. 17.4%; 54.9% vs. 65.2%; 0 vs. 2.2%; X2=14.35，P<0.01), suicide ideation (51.1% vs. 64.0%, P<0.05) and prior suicide attempts (8.4% vs. 15.0%, P<0.05) in compound crisis callers were significantly higher. There were more compound crisis callers with over 50% hopelessness (51.9% vs. 31.0%，X2=11.96，P<0.01). Conclusion: As predicted, among middle-aged and elderly participants, mixed-stressor and compound crisis callers were higher in degree of severity of depression and suicidality. Intervention strategies should be developed addressing to specific stressor or stressors. The promotions of crisis callers’ medical help seeking behavior need to be emphasized.