Resource connectivity for beneficial insects in landscapes dominated by monoculture tree crop plantations

Homogenization of agricultural landscapes affects ecological processes and biodiversity and can affect the community composition of ecosystem service providers. These effects can have particular impact in landscapes dominated by monocultures of pollinator-dependent tree crop plantations, which create both spatial and temporal homogeneity at the landscape scale. I looked for associations between the proportion of nearby unmanaged vegetation and potential wild pollinator groups collected within flowering almond orchards in two types of landscape. In the Complex landscape, characterized by a heterogeneous mosaic of multiple crops, semi-natural grassland and natural woodland, insect pollinator groups were not associated with unmanaged vegetation. In the Simple landscape, dominated by monoculture almond plantations, most pollinator groups showed positive relationships with the two unmanaged vegetation types (grassland and woodland). In particular, all wild bee and all but one hoverfly individual were found in remnant native vegetation patches within almond plantations, rather than within rows of almond trees. More research is necessary to identify how structural differences created in monoculture landscapes, between crops and the native vegetation they encroach on, influence ecological communities and the provision of ecosystem services.     

我国农业野生植物资源原生境保护区建设现状、问题及未来的思考

我国农业野生植物原生境面临着环境污染、人类农业生产、经济社会发展以及各类违法活动的侵蚀和破坏,建立原生境保护区是保护农业野生植物资源的重要途径之一。基于对当前威胁我国农业野生植物原生境面临的四大因素(自然灾害、农业活动、经济发展、违法活动)的系统梳理的基础上,探讨了现有农业野生植物原生境保护区建设的法规政策体系以及保护区建设现状和存在的主要问题,在此基础上提出了加强保护区建设的几点建议。分析结果表明,当前我国农业野生植物保护区建设存在的主要问题包括:保护区土地权属界定、保护区建设内容限定过窄、忽视保护区管理机构能力建设、对保护区周边农民权益保护不够。为了提高保护区建设工作,文章建议相关部门应该重视以下几个问题:统筹协调行业部门之间的权属差异,重视农业野生植物异位保存工作,修订完善保护区建设技术规范,兼顾保护区民众利益。     

OUTPUT FLUCTUATIONS PERSISTENCE: DO CYCLICAL SHOCKS MATTER?

The aim of this paper is to identify the different sources of persistence of output fluctuations. We propose an unobserved components model that allows us to decompose GDP series into a trend component and a cyclical component. We let the drift of the trend component switch between different regimes according to a first‐order Markov process. To calculate an appropriate p‐value for a test of linearity we propose a bootstrap procedure, which allows for general forms of heteroscedasticity. The performance of the bootstrap is checked by means of a Monte Carlo simulation. Our study concerns the USA. We find that cyclical shocks appear to play an important role on the observed persistence of output.     

山野菜清洗除杂设备的整体设计

采用国际先进的气水辊刷喷淋联合清洗新工艺,山野菜经过气水两相的强烈搅混作用和气泡爆裂产生的声波成为振动源的作用而清除泥土和杂物,再经辊刷对植物叶片和毛发等的粘附作用以及高压水喷淋达到清洗干净。     

Quantile serial dependence in crude oil markets: evidence from improved quantilogram analysis with quantile wild bootstrapping

We examine the quantile serial dependence in crude oil prices based on the Linton and Whang’s quantile-based portmanteau test which we improved by means of quantile wild bootstrapping (QWB). Through Monte Carlo simulation, we find that the quantile wild bootstrap-based portmanteau test performs better than the bound testing procedure suggested by Linton and Whang. We apply the improved test to examine the efficiency of two crude oil markets – WTI and Brent. We also examine if the dependence is stable via rolling sample tests. Our results show that both WTI and Brent are serially dependent in all, except the median quantiles. These findings suggest that it may be misleading to examine the efficiency of crude oil markets in terms of mean (or median) returns only. These crude oil markets are relatively more serially dependent in non-median ranges.     

Assessing the role of components of life satisfaction

Factors affecting subjective well-being and their gross effect measurement have been widely studied. However, how people derive utility from these factors has not been fully explored. This article provides a way to decompose the gross effect of major determinants on life satisfaction into direct and indirect effects and make inference for the latter. Because the indirect effect is nonlinear in parameters associated with different models in an equation system, it creates a problem in estimating the standard error. Besides, the categorical nature in survey data further introduces bias to the covariance estimation even asymptotically. To address these issues without knowing the form of heteroskedasticity under the null hypothesis, we propose to extend the wild bootstrap procedure in this particular context. Its robustness against various data properties is validated via several simulation experiments. Using three recent waves of World Values Survey, we find that the relative importance of life control has significantly increased recently, and endowing citizens with the right to enjoy their freedoms and liberties is a more effective policy in raising life satisfaction than promoting national income.     

东亚“雁阵模式”式微原因新析及启示

经济全球化时代,维系“雁阵模式”运行的宏观背景条件正在丧失,“雁阵模式”开始走向终结。日本经济的“制度疲劳”、“四小龙”的兴起、中国的崛起以及亚洲金融危机只是“雁阵模式”式微的表层原因,其真正原因是经济全球化及其机制的作用:即全球信息化、世界经济一体化、跨国公司的发展、知识经济在世界范围的兴起,成为“雁阵模式”终结的力量。“雁阵模式”的终结对于中国产业结构调整与优化,具有重要启示作用。     

冰雪灾害对野生动物的影响与恢复的思考

对2008年雪灾的受灾点广东省大瑶山保护区进行实地考察,通过样线和访谈的方法进行了调查,结合当地情况系统地分析了冰雪灾害对野生动物的影响;对灾区野生动物的恢复提出了思考性意见.     

我国保护珍稀濒危野生植物资源的法律思考

分析我国珍稀濒危野生植物资源的有关法律法规，阐述法律保护珍稀濒危野生植物资源的立法状况，重点剖析2002年刑法修正案（四）出台的背景及其所规定的“违反国家规定”“国家重点保护的其他植物”相关法律规定，根据司法实践，提出统一国家重点保护植物的刑法概念，统一刑法规定的罪刑相当原则。刑法修正案（四）的出台，有效地补充了1997年刑法在环境资源犯罪立法上的许多缺陷，但是与之配套的司法解释至今尚未出台，因而在司法实践中还不能最大限度地打击破坏珍稀濒危野生植物资源的犯罪行为，结合司法实践中存在的问题，提出完善我国保护珍稀濒危野生植物资源法律体系的建议。     

贵南县莫曲沟林区常见野生植物资源及其开发利用

据调查，莫曲沟林区共有维管束植物45科，136属，208种，其中国家二级珍稀保护植物4种，青海省重点保护林木4种，中藏药材30余种，有利用价值和发展前途的植物在90种以上；介绍了野生植物保护、开发利用措施。