Silphids in urban forests: Diversity and function

Many ecologists have examined the process of how urbanization reduces biological diversity but rarely have its ecological consequences been assessed. We studied forest-dwelling burying beetles (Coleoptera: Silphidae)—a guild of insects that requires carrion to complete their life cycles—along an urban-rural gradient of land use in Maryland. Our objective was to determine how forest fragmentation associated with urbanization affects (1) beetle community diversity and structure and (2) the ecological function provided by these insects, that is, decomposition of vertebrate carcasses. Forest fragmentation strongly reduced burying beetle diversity and abundance, and did so far more pervasively than urbanization of the surrounding landscape. The likelihood that beetles interred experimental baits was a direct, positive function of burying beetle diversity. We conclude that loss of burying beetle diversity resulting from forest fragmentation could have important ecological consequences in urban forests.     

Improved Monte Carlo inference for models with additive error

Some statistical models defined in terms of a generating stochastic mechanism have intractable distribution theory, which renders parameter estimation difficult. However, a Monte Carlo estimate of the log-likelihood surface for such a model can be obtained via computation of nonparametric density estimates from simulated realizations of the model. Unfortunately, the bias inherent in density estimation can cause bias in the resulting log-likelihood estimate that alters the location of its maximizer. In this paper a methodology for radically reducing this bias is developed for models with an additive error component. An illustrative example involving a stochastic model of molecular fragmentation and measurement is given.     

慕课与高校人文素质课的契合问题探讨——以“互联网+教育”为背景

基于诸多因素,我国大多数高校人文素质课存在教学资源不足、教学质量不高等问题。目前,部分高校已将慕课引入人文教育中,但以慕课的形式开展人文素质教育又带来了新的问题。本文在“互联网+教育”的背景下,探讨高校慕课与人文素质课的契合问题。     

农村社会结构碎样化问题分析

改革开放使农村社会结构日益呈现碎样化,农村社会结构的解体影响着新农村建设的成就。必须在建设新农村的过程中分析农村社会结构碎样化的成因及表现形式,分析其对社会的影响,找出一条解决农村社会问题的途径,重新整合农村社会,建设新农村。     

微信公共账号传播的机制与策略

微信及其用户创造了一个全新的时代。微信公共账号的产生则赋予了其更多的媒介特质,也为传播学研究提供了更为丰富的实践。微信公号具有大众传播属性、人际传播功能和交互式传播特点,它体现了传播学研究中的使用与满足理论、强关系理论和受众碎片化趋势。同时微信公号传播也存在诸多困境,可以从定位、媒介融合、互动、推广、监管等方面进行改进,实现其长远发展。     

土地细碎化必然导致土地生产效率降低？——对土地细碎化与土地生产效率研究的批判性分析

通过文献研究,讨论土地细碎化的内涵及其形成原因,发现对于土地细碎化与土地生产效率关系的研究主要采用地块大小和地块数量2个指标,来自世界各地的经验研究结果显示,农户拥有的地块数量对土地生产效率具有负面作用,地块大小对其具有正面作用.从地块数量和地块大小对土地生产效率的作用合力来看,土地细碎化导致土地生产效率低下这一传统观点并没有得到完全验证.分析国内外关于世界各地土地细碎化与土地生产效率的经验研究的评述和理论发现,土地细碎化在不同的生产条件下对土地生产效率会产生不同影响,土地细碎化并不必然导致土地生产效率的降低.提出在推动农村向土地规模化生产转变进程中,应严格考察不同地区土地细碎化及与之相匹配的农户生产条件,特别是农村人地比例的变化,才能得出可靠的土地制度改革方向.     

无偿转入土地对粮食生产效率的影响：福利还是负担？

在分析无偿转入土地对粮食生产效率影响的基础上,运用逆概率加权的方法,实证检验了其影响效果与作用机理。研究发现,与有偿转入土地相比,无偿转入土地是基于家庭社区伦理关系的非市场化行为。在解决了样本选择偏误的基础上,无偿转入土地整体上不利于粮食生产效率提升。其中的原因在于,流转租金缺位的无偿转入土地更容易弱化要素价格的信号功能与农户的生产改进意愿,进而使其在土地细碎化与农业长期投资上不能得到与有偿转入土地农户相同的改进。这一消极影响在户主年龄较小或文化程度较高、获得农业补贴较多或市场化水平较低、转入土地规模较小或期限不明确的农户群体中更为突出。长期来看,随着农村集体经济与新型农业经营主体的继续发展壮大,农村土地无偿流转的情况或将持续减少。但同时,也仍应当充分尊重土地无偿流转的现实选择与价值,立足于各地的具体情况来识别与谋划今后规模化经营的具体方向。     

空间流变与文化持守:一个移民羌村信仰习俗空间化表征的案例研究

表征的空间是列斐伏尔空间生产理论的重要议题,但在民族村寨领域还未引起足够重视。民族村寨空间生产是关于空间－人－文化三者共存秩序的复杂建构过程,其中村民弱小、碎片的空间实践机制研究有待加强。本文以一 个移民羌村为案例,在田野调查基础上,从空间生产的微观视角出发,对羌村的居住信仰、释比信仰、习俗信仪、羌年祭典四个方面信仰习俗的空间化表征展开研究。研究发现,在空间－人－文化三元互动中,羌民弱小、碎片化的空间实践使特定信仰习俗得以自洽地存续,新村表征的空间背后既是羌民“化他乡为故乡”的主体性呈现,更是羌民对本民族文化的坚定持守。     

Governing Deviance in Public Space through Mayoral Orders: Fields Mismatch and Metropolitan Turbulence

This article addresses the issue of policy change and its consequences on the organizational field and institutional context, looking at the role of an instrument transfer process. We adopt a political sociology approach to policy instruments to account for the impact that the introduction of a securitarian instrument, the mayoral order, had on the implementation process of a social policy. Through a genealogy of the instrument we identify a constitutive, normative and cognitive dimension. Our aim is to explain the interaction between these institutional dimensions, the re‐definition of the organizational field of the policy, and the dynamics of metropolitan politics. Following a synthesis of the policy process and the institutional arrangements where the policy is implemented, we show how the instrument transfer triggered a division within the organizational field, and the rise of institutional tensions amongst local authorities. In the conclusion, we identify the institutional dimensions of the instruments and the policy implementation scale as elements that are to interact with public‐private relationships and institutional arrangements, and that have an impact on implementation process and policy outcome.     

碎片化构筑的智力博弈——电影《太阳照常升起》叙事分析

《太阳照常升起》以崭新的视角和独特的叙述方式吸引着观众的视线。这种独特的叙事主要呈现为碎片化的特征,即从组合段叙事、非情节叙事、开放式结局三个方面对影片进行阐释,并展示导演和观众间的一种智力博弈。