土地承包关系“长久不变”下无地农民权益保障机制研究

“增人不增地,减人不减地”、土地承包关系“长久不变”、土地确权登记颁证等农村集体土地产权制度改革措施,一方面,固化了农村现有人地之间的权利义务关系,强化了农民对分得承包地的财产功能;另一方面,也使部分农民丧失了凭借集体成员身份获得承包地的机会而沦为无地农民,失去了依靠承包地获得种地收益及国家农业补贴的权利,影响了他们的可持续生计,极易诱发潜在的社会矛盾与冲突。通过文献梳理,分析无地农民依靠传统的土地调整和土地经营权流转两种模式获得承包地,不仅在理论上存在着争议,而且在现实中存在着瓶颈和障碍;然后,在土地承包关系“长久不变”背景下,尝试构建起“有地分地,无地赋权”的无地农民权益保障机制,该权益保障机制具体包括:“分地”机制、“赋权”机制、“分地”与“赋权”相并行机制。不同集体经济组织因地制宜地根据各自的“三资”状况、享有权益保障资格的无地农民人数等选择确定适合本地区的无地农民权益保障机制;同时,“分地”机制、“赋权”机制、“分地”与“赋权”相并行机制存在着不同的内在运行机理,具体而言,第一,“分地”机制。在集体经济组织内掌握有机动地、通过依法开垦等方式增加的土地、农民在自愿有偿前提下交回或退出的土地、收回“消亡户”的土地等依法可用于再分配的土地资源时,应尽可能扩大这些类型的土地来源与数量,科学确定无地农民应分得承包地数量标准,建立起合理的无地农民轮候排地的次序规则;第二,“赋权”机制。在集体经济组织没有掌握依法可用于再分配的土地资源时,采用赋予无地农民集体资产收益分配权、集体公益性岗位优先权、股权等方式保障其合法权益,以替代土地对农民的社会保障功能。第三,“分地”与“赋权”相并行机制。当集体经济组织既掌握有依法可用于再分配的土地资源,又有赋权空间时,无地农民可根据自身意愿在“分地”与“赋权”两者之间选择一项或者选择两者有机搭配以保护自己的合法权益,以真正实现宏观的权益保障方式与微观的个体需求之间的精准匹配性。

第二轮土地延包中无地少地农户的权益保障策略研究

持续强化农村地权稳定性的农村土地制度改革走向,给农民吃下了一颗土地权利"定心丸",激励了农户对承包地的长期投资。但是,由于漫长的第二轮土地承包期内不同农户人地数量变化的异质性和不均衡性,也诱发了无地少地农户这一特殊群体的权益保护问题。在第二轮土地承包到期后再延长三十年的实施过程中,如若无视无地少地农户的渴望和诉求,不仅会固化其弱势身份,使其落入贫困边缘,还会极大阻碍乡村振兴之路,间接影响整个社会的和谐发展。然而,地权固化使得集体经济组织很难再通过土地发包或者土地调整来解决不同农户的人地不均衡问题。因此,本研究在界定无地少地农户的概念和构成的基础上,分别探寻无地农户和少地农户的形成原因,从分地和赋权两个层面构建起无地少地农户的权益保障机制,以减少第二轮土地承包到期后再延长三十年政策贯彻落实中的阻力和障碍。

Driving Mechanism of Cultivated Land Transition in Yantai Proper,Shandong Province,China

Cultivated land transition and its driving mechanism are the hotspots among studies on land use change. In this study, we constructed a framework to study the driving mechanism of cultivated land transition from the quantitative perspective. Based on the vector data of land use in 1990, 2000 and 2009 of Yantai Proper, Shandong Province China, 11 explanatory variables were chosen from two aspects: the elevation, slope, cost distance to major water area and cost distance to minor water area, which presented physical factors; cost distance to district center, cost distance to town center, cost distance to city expansion center, cost distance to major roads, cost distance to city roads, cost distance to county roads and cost distance to rural roads, which presented the socio-economic factors. Combined with spatial analysis tools and Logistic regression analysis model, we construct Logistic regression analyses with four objectives that were urban construction land, rural residential land, orchard and other lands. The results show that, cost distance to district center, cost distance to town center, cost distance to city expansion center and cost distance to city roads are the significant explanatory variables for the transition of cultivated land into urban construction land. The main explained factors on the transition of cultivated land into rural residential land are slope, cost distance to town center, cost distance to county roads and cost distance to rural roads. Slope, cost distance to minor water area, cost distance to town center, cost distance to county roads and cost distance to rural roads are the significant explanatory variables for the transition of cultivated land into orchard land. Elevation, slope, cost distance to major water area and cost distance to minor water area are the main explanatory variables on the transition of cultivated land into other land uses.

Research on the Activity Characteristics of Small Earthquake Swarms in the Muli Area of Sichuan Province

In this article,we relocated the seismic source location of the earthquakes in the Muli area of Sichuan,inverted the focal mechanism of the larger earthquakes and analyzed the relationship between the water level of the Jinping reservoir and the frequency of the earthquake swarm. The results show that:( 1) The epicenters of the relocated small earthquake swarms are distributed in a seismic zone,and the earthquake focal depths were in the range of 0- 12 km.( 2) By analyzing the earthquake swarm spatial distribution,we found that the swarms were generated by one branch fault on the west of Xiaojinhe fault.( 3) The focal mechanism of the three earthquakes with magnitude greater than 4. 0 is significantly different,with the shallow source thrust events affected by vertical stress,and the strike-slip events are related to regional stress tectonic activity.

Consistent Distribution of Stress before Strong Earthquake from Focal Mechanisms

At some stage of a strong earthquake preparation, the focal mechanisms of small earthquakes have roughly the same direction with the tectonic stress field. According to this feature, we define the angle between P, B and T axis of focal mechanisms and the three stress axes of tectonic stress field as the consistency parameter a in studying the dynamic changes of stress fields in earthquake preparation areas. We mainly analyze the changes of the consistency parameter a of the Mw8. 3 Knril island arc earthquake and the Mw8. 4 Peru earthquake. Our study shows that before the strong earthquakes, the earthquake area saw a low consistency, and the focal mechanisms of a series of small earthquakes had small differences in the directions with the tectonic stress field, which means the foreshocks were under the control of the stress field. On the other hand, a higher consistency means the focal mechanisms of their aftershocks are scattered and have big differences in the directions with the tectonic field, which indicate that the control of background stress field starts weakening.

Seismic Sequence Characteristics and Precursory Anomalies of the M_S6.3 and M_S6.4 Da Qaidam Earthquakes in 2008～2009

In this paper,the seismogenic structures of the Da Qaidam strong earthquakes are preliminarily discussed by using the regional seismotectonic data and focal mechanism solutions. Analysis is done on the temporal and spatial distribution characteristics of the two strong earthquake sequences in Da Qaidam in combination with the sequence distribution characteristics of the M6. 6 earthquake of 2003 and the five strong earthquakes of about M5. 0 in 2004 in Delingha. At the same time,the regional characteristics of the historical seismic activity are also investigated. Preliminary analysis is done on the influence of the two M8. 0 earthquakes in the past 10 years on this region. Precursory anomalies and their characteristics are discussed in combination with the analysis of the precursor observation data of Qinghai Province.

The spatiotemporal characteristics of spring phenophase changes of Fraxinus chinensis in China from 1952 to 2007

We selected widely distributed and well observed plant species Fraxinus chinensis to study the formation mechanism of geographical distribution of the plant phenophase changes and revealed their spatiotemporal dynamics in China. Based on the first leaf date （FLD） data at 12 sites derived from Chinese Phenological Observation Network （CPON） and related meteoro- logical data, we developed and validated the process-based model of FLD for Fraxinus chinensis. After reconstructing data series of FLD for Fraxinus chinensis over the study area from 1952 to 2007, we analyzed different spatiotemporal patterns of phenophase changes of this species. The results suggested that the process-based model was able to simulate the FLD accu- rately for Fraxinus chinensis on large spatial and temporal scales, because of the consideration of different budding rate re- sponded to the air temperatures during the dormancy and the quiescence in accordance with the physiological mechanism of plants. The geographical distribution of the spring phenology in temperate regions was determined by the spatial pattern of daily average air temperature. The changes of FLD for Fraxinus chinensis revealed significant phenological advances in most areas. However, it showed delayed trends in a few sites. The overall average change trend was -1 .l days/decade. This result was consistent with the advanced trend in other regions of the North Hemisphere. The changes of FLD showed a noticeable regional variation with clearer advance in the north than in the south. The FLD in northern China showed an average ad- vance as high as -2.0 days/decade （P〈0.01）. And the advance in northeastern and northwestern China was respectively -1.5 and -1.4 days/decade （P〈0.01）. Furthermore, eastern and central regions showed a minor trend, which was -1.0 days/decade （P〈0.05）. The smallest and non-significant advance appeared in southwestern and southern China.

Comparative transcriptome analysis of the lichen-forming fungus Endocarpon pusillum elucidates its drought adaptation mechanisms

The lichen-forming fungus was isolated from the desert lichen Endocarpon pusillum that is extremely drought resistant.To understand the molecular mechanisms of drought resistance in the fungus,we employed RNA-seq and quantitative real-time PCR to compare and characterize the differentially expressed genes in pure culture at two different water levels and with that in desiccated lichen.The comparative transcriptome analysis indicated that a total of 1781 genes were differentially expressed between samples cultured under normal and PEG-induced drought stress conditions.Similar to those in drought resistance plants and non-lichenized fungi,the common drought-resistant mechanisms were differentially expressed in E.pusillum.However,the expression change of genes involved in osmotic regulation in E.pusillum is different,which might be the evidence for the feature of drought adaptation.Interestingly,different from other organisms,some genes involved in drought adaption mechanisms showed significantly different expression patterns between the presence and absence of drought stress in E.pusillum.The expression of 23 candidate stress responsive genes was further confirmed by quantitative real-time PCR using dehydrated E.pusillum lichen thalli.This study provides a valuable resource for future research on lichen-forming fungi and shall facilitate future functional studies of the specific genes related to drought resistance.

Frequency-dependent rupture process,stress change,and seismogenic mechanism of the 25 April 2015 Nepal Gorkha M_w 7.8 earthquake

On 25 April 2015,an M_w 7.8 earthquake occurred on the Main Himalaya Thrust fault with a dip angle of^7° about77 km northwest of Kathmandu,Nepal.This Nepal Gorkha event is the largest one on the Himalayan thrust belt since 1950.Here we use the compressive sensing method in the frequency domain to track the seismic radiation and rupture process of this event using teleseismic P waves recorded by array stations in North America.We also compute the distribution of static shear stress changes on the fault plane from a coseismic slip model.Our results indicate a dominant east-southeastward unilateral rupture process from the epicenter with an average rupture speed of ~3 km s^(-1).Coseismic radiation of this earthquake shows clear frequency-dependent features.The lower frequency(0.05-0.3 Hz) radiation mainly originates from large coseismic slip regions with negative coseismic shear stress changes.In comparison,higher frequency(0.3-0.6 Hz) radiation appears to be from the down-dip part around the margin of large slip areas,which has been loaded and presents positive coseismic shear stress changes.We propose an asperity model to interpret this Nepal earthquake sequence and compare the frequency-dependent coseismic radiation with that in subduction zones.Such frequency-dependent radiation indicates the depth-varying frictional properties on the plate interface of the Nepal section in the main Himalaya thrust system,similar to previous findings in oceanic subduction zones.Our findings provide further evidence of the spatial correlation between changes of static stress status on the fault plane and the observed frequency-dependent coseismic radiation during large earthquakes.Our results show that the frequency-dependent coseismic radiation is not only found for megathrust earthquakes in the oceanic subduction environment,but also holds true for thrust events in the continental collision zone.