长江中下游粮食主产区耕地利用生态效率区域差异与空间收敛

基于耕地利用生态效率内涵构建其评价指标体系,并运用SBM-Undesirable模型、核密度估计法及空间收敛模型,对长江中下游粮食主产区71个市（州）耕地利用生态效率区域差异及收敛态势定量刻画。结果表明：（1）2007—2018年长江中下游粮食主产区耕地利用生态效率整体水平中等,各粮食主产区效率差异明显,效率损失主要源于投入冗余所带来的投入非效率,其中劳动力投入冗余度最高;（2）时间维度上看,长江中下游粮食主产区整体耕地利用生态效率始终存在两级分化的现象,整体内部差异呈扩大趋势,但逐步趋于稳定,各粮食主产区内部差异演变具有较大分异性;（3）空间维度上看,考虑空间溢出效应的情境下,长江中下游粮食主产区整体存在显著的绝对β收敛,且在科技水平、农户收入水平、灌溉水平及空间溢出效应等因素的共同影响下以1.01%的速度条件收敛,但各粮食主产区收敛态势具有区域差异性。应建立粮食主产区协同机制,因地制宜,分区施策以提升长江中下游粮食主产区耕地利用生态效率水平。     

从田块到水体：基于源-流-汇理念的非点源污染全过程核算方法

目前,国内外已开展了大量农业非点源污染核算研究,但大部分经验模型缺乏对非点源污染入水体过程的考虑,而机理模型则受到资料限制,大尺度应用难度较大.针对传统研究面临的未考虑入水体过程、难以精细化模拟等核心问题,本研究基于源-流-汇理念和栅格汇流算法,构建了耦合源负荷核算、入水体过程核算、植被截留核算等模块的农业非点源污染物全过程核算方法(Grid confluence based agricultural nonpoint source pollution calculation method,GC-ANPSM).案例研究表明,GC-ANPSM方法具有较好的适用性,径流模拟误差为24.3%,总氮模拟误差为9.78%.该方法可为少监测资料地区的农业非点源污染物全过程核算提供理论和技术基础,同时为制定农业环境保护政策提供决策依据.     

Mapping convergence points in the initial emergency response to 9/111

In response to extreme events, researchers have recognised the convergence of volunteers, emergency responders, and other individuals and organisations. In 2000, geographer Paul Routledge presented the concept of convergence spaces as a theoretical means to explain social movements. In applying this concept, this paper explores the geographic space in which organisations and individuals converged immediately following the 11 September 2001 attacks on the World Trade Center. The paper begins to answer the question of whether there were in fact any patterns of convergence among the locations utilised by organisations responding to the attacks. Using data collected from field documents, these geographic locations are mapped over 12 days to help identify possible patterns of clustering. Results of this analysis will begin to provide researchers, policy makers and practitioners with a better understanding of how emergency response evolves geographically following an event.     

Social experience influences the development of a central auditory area

Vocal communication develops under social influences that can enhance attention, an important factor in memory formation and perceptual tuning. In songbirds, social conditions can delay sensitive periods of development, overcome learning inhibitions and enable exceptional learning or induce selective learning. However, we do not know how social conditions influence auditory processing in the brain. In the present study, we raised young naive starlings under different social conditions but with the same auditory experience of adult songs, and we compared the effects of these different conditions on the development of the auditory cortex analogue. Several features appeared to be influenced by the social experience, among which the proportion of auditory neuronal sites and the neuronal selectivity. Both physical and social isolation from adult models altered the development of the auditory area in parallel to alterations in vocal development. To our knowledge, this is the first evidence that social deprivation has as much influence on neuronal responsiveness as sensory deprivation.     

Dynamic Changes,Regional Differences,and Influencing Factors of CO2 Emission Performance in China

Abstract

This paper proposes to use DEA models with undesirable outputs to construct the Malmquist index that can be use to investigate the dynamic changes of CO₂ emission performance. With the index, the authors have measured the CO₂ emission performance of 28 provinces and autonomous regions in China from 1996 to 2007; with the convergence theory and panel data regression model, the authors analyze the regional differences and the influencing factors. It is found that the performance of CO₂ emissions in China has been continuously improved mainly due to the technological progress, and the average improvement rate is 3.25%, with a cumulative improvement rate of 40.86%. In addition, the CO₂ emission performance varies across four regions. As a whole, the performance score of eastern China is the highest. The northeastern and central China has relatively lower performance scores, and the western China is relatively backward. The regional differences are decreasing, and the performance of CO₂ emissions is convergent. The influence of some factors on the performance of CO₂ emissions is significant, such as the level of economic development, the level of industrial structure, energy intensity, and ownership structure. The influence of some factors, such as opening-up to the outside world, on the performance of CO₂ emissions is not significant.     

Greenhouse gas emission reductions in the post-Kyoto period: Emission intensity changes required under the 'contraction and convergence' approach

Various approaches have been proposed for allocating commitments to countries regarding the mitigation of greenhouse gas emissions. One of these methods is the ‘contraction and convergence’ approach, which defines emission permits on the basis of converging per capita emissions under a contracting global emission profile. The approach is unique in its simplicity. Only two major issues need to be negotiated and agreed upon: the target atmospheric concentration of CO₂ and the date when the entitlements are to converge at equal per capita allocations. According to the contraction and convergence approach, developing countries can continue their current emission trends, whereas industrialized countries should reduce their emissions quite dramatically. This regime represents a shift away from the current approach towards defining commitments for all parties and their evolution over the long term. This article analyses how allocation schemes determined by the contraction and convergence approach might affect certain OECD and non‐OECD countries. Results for eleven countries selected for analysis (United States, United Kingdom, Germany, France, Japan, China, Venezuela, Thailand, Brazil, India and Indonesia) reveal that trends observed in the past few decades in most industrialized countries will lead to the contraction and convergence target.     

Convergence and emergence in organizations: An integrative framework and review

In reaction to the growing attention to connecting individual‐level and unit‐level constructs, we first briefly review emergence terminology and theories that address the dynamic process by which a higher‐level phenomenon emerges from lower‐level elements. Next, we review the extant theory and research on emergence and convergence in organization science using an organizing framework that simultaneously considers the content area of lower‐level elements, the emergent factors, and the target of the emergent property. In addition to organizing and bridging current literature on emergence and convergence, gaps of existing research and new directions for future research, including compilation and divergence, are identified. Copyright © 2015 John Wiley & Sons, Ltd.     

Vocal mediation of foraging competition in the cooperatively breeding green woodhoopoe (<Emphasis Type="Italic">Phoeniculus purpureus</Emphasis>)

Many group-living species produce frequent vocalisations when foraging, but the function of these food-associated calls is often difficult to divine. I investigated the kek call of the cooperatively breeding green woodhoopoe (Phoeniculus purpureus), a species in which individuals have preferred foraging techniques dependent on their bill size. Individuals called at a greater rate (1) in foraging compared to non-foraging situations, and (2) in groups containing potential foraging competitors (i.e. individuals that foraged using the same preferred techniques). I therefore asked whether the kek call is used to recruit conspecific foragers or whether it acts as a vocal signal of foraging niche and mediates foraging competition. Foragers that were vocalising were no more likely to be approached than those that were silent, and individuals gained no foraging advantage from the close proximity of another group member. Thus, keks are unlikely to be used to recruit conspecifics. Instead, they appear to regulate spacing between potential foraging competitors. Although an individual forager was equally likely to be closely approached by all other group members, it increased its calling rate only in response to potential foraging competitors. This increase in calling rate resulted in the approaching individual moving away, thus maintaining some separation between individuals that forage in the same way. Maintenance of such spacing is important because the success rate of an individual decreased when a foraging competitor was close by.Communicated by M. Leonard     

Whistle sharing in paired male bottlenose dolphins,<Emphasis Type="Italic"> Tursiops truncatus</Emphasis>

The signature whistle hypothesis states that dolphins produce highly stereotyped, individually distinctive whistles when in isolation. The presence of signature whistles has been called into question by recent studies proposing that dolphins produce a shared, simple upsweep whistle when in isolation, and that whistles produced by socializing dolphins are shared across individuals and social groups. This shared repertoire hypothesis suggests that when two animals produce the same whistle type, it is due to sharing the same common repertoire rather than one animal learning to produce the whistle of another. One difference between studies supporting or denying the existence of signature whistles is the method used to classify whistle types. We examined whistle production by 17 free-ranging bottlenose dolphins while temporarily restrained. We used both a quantitative comparison technique similar to that used to support the shared repertoire hypothesis and human judges to classify whistle types and quantify similarity between types. Contrary to recent studies that emphasize shared whistles, overall whistle sharing between isolated individuals was low (25%) and a simple upsweep did not account for the most common whistle type in half of the animals. Some species of birds, bats, and primates with stable social groups use vocal learning to converge over time to one common group distinctive call type. We examined whistle similarity between adult male dolphins that are partners in a close social alliance in order to test whether vocal learning may enable a similar vocal convergence. Whistle similarity was rated very high between partners and low between non-partners by both the quantitative technique and human observers. This suggests that as in songbirds and some other mammals, adult male bottlenose dolphins may use vocal learning to converge on similar whistles as they develop affiliative social relationships.Communicated by G. Wilkinson     

The Information Content of a Scalar Plume – A Plume Tracing Perspective

The ability of many animals and insects to track a plume to its source is a particularly impressive feat when the fluid dynamics is considered. Inspired by this observation this research seeks to identify the information in a passive scalar plume suitable for developing robust and efficient plume tracing algorithms. The subject of this study is a scalar plume emanating from a point source in a turbulent boundary layer which has been modeled in a laboratory facility built specifically for this purpose. A coupled PIV-LIF technique is used to measure the velocity and scalar field in a time resolved fashion. This data set is analyzed and the convergence rates of five single-point statistics, suitable as kernels of plume tracing algorithms, are investigated. The experimental data shows that the scalar fluctuations over long downstream distances from the source are characterized by filamentary structures that lead to relatively slow convergence rates for any statistic that is based on mean concentrations. The scalar intermittency, however, converges rapidly toward its true value, in fact converging to a testable hypothesis for source location direction faster than the time scale of the larger scale plume meander.