农作物面积抽样单元空间变异性及其对抽样外推效率的影响

［目的］联合遥感和传统抽样方法的空间抽样技术是进行大区域农作物面积监测的有效手段。但传统抽样要求抽样单元间相互独立,并未考虑到区域农作物空间变异性的存在对农作物面积空间抽样效率是否有影响及其影响程度如何,从而限制了农作物面积监测的效率和精度。［方法］文章以吉林省德惠市为研究区,利用变异函数分别对10种抽样单元尺度内玉米和水稻种植面积的空间变异性进行定量评价。选择3种空间抽样方案（简单随机抽样、系统抽样、分层抽样）,分别计算不同空间变异程度下的样本容量（n）、抽样相对误差（Re）和总体总值估计量的变异系数（CV（Y︿））作为空间抽样效率的评价指标,定量分析空间变异性对农作物面积空间抽样效率的影响,提出适宜空间变异农作物的空间抽样优化方案。［结果］(1)玉米和水稻面积的空间变异性（反映为基台值C0+C）均随着抽样单元尺度的增加逐渐而减小,其中500m×500m和2 500m×2 500m抽样单元尺度下农作物面积的空间自相关程度相对最小。(2)相同抽样比下,农作物面积在3种抽样方法下的相对误差和变异系数均随着空间变异性的减小（抽样单元尺度增加）逐渐增大,其中玉米和水稻在分层抽样条件下的相对误差和变异系数具有相对最小值,分别限制在10%和20%以内,其次为系统抽样（Re<40%,CV（Y︿）<88%）和简单随机抽样（Re<50%,CV（Y︿）<75%）。 在抽样方法被选定的情况下,两种农作物的分层抽样相对误差变化率随着抽样比的增加迅速降低,当抽样比增至5%时,其相对误差和变异系数的变化率基本趋于稳定,继续增加抽样比来提高抽样精度的效果甚微。 在3 500m×3 500m抽样单元尺度内,按5%抽样比确定的样本容量对玉米和水稻面积进行分层抽样时,可达到95%的抽样精度（Re<5%）。 综合农作物在不同抽样单元尺度下的空间变异特征和空间抽样效率,基于2 500m×2 500m的抽样单元尺度和5%抽样比进行分层抽样的空间变异性农作物空间抽样方案是一种高精度、低成本、代表性强的空间抽样方案。［结论］该研究为区域农作物面积抽样调查方法的改善和抽样效率的提高提供技术支持和参考依据。     

The many shades of ‘openness’: an application of item response theory to open innovation research

This study addresses one of the most basic research questions investigated in the Open Innovation (OI) literature: how open are firms? This question has remained partially unanswered given the challenges encountered by empirical research in assessing the relevance of specific OI practices within the OI model, as well as the types of activities perceived by managers as OI benefits or concerns. To provide an answer to this question, we suggest a framework using Item Response Theory to improve over current measures of firms' openness and test it on a sample of 383 technology‐based SMEs. Our theoretical model conceives openness as an instance of how firms make decisions regarding the adoption of different OI practices based on their evaluation of OI benefits and concerns. Focusing on the relationship between firm‐level differences in terms of openness and the types of OI practices adopted by these firms, we show that significantly different levels of ‘OI maturity’ are required to broaden the scope of external partnerships and to shift from non‐pecuniary OI modes (relation‐based approaches) toward pecuniary (transaction‐based) practices. Our results have relevant implications for the OI literature and provide new managerial insight into OI adoption.     

Technology Exploitation Paths: Combining Technological and Complementary Resources in New Product Development and Licensing

Technological resources in the form of patents, trade secrets, and know‐how have become key assets for modern enterprises. This paper addresses a critical issue in technology and innovation management, namely, the commercial exploitation of technological resources resulting from research and development (R&D) investments. Extracting economic value from these resources by maximizing the benefits for shareholders is an extremely challenging task because technological resources are intangible, idiosyncratic, uncertain, predominantly tacit, and with poorly defined property rights. In their attempt to extract the maximum value from their technological resources, firms increasingly combine their internal exploitation through new product development (NPD) with external exploitation through licensing. However, most existing studies on NPD and technology licensing have treated the two exploitation paths independently and in isolation, which has resulted in two separate research streams using different theories and addressing different managerial challenges. The purpose of this paper is to contribute to filling this gap by developing and testing a comprehensive conceptual framework that simultaneously considers the antecedents affecting the successful implementation of NPD and licensing strategies as well as their consequences on firm profitability. The paper in particular investigates the effects of the interplay between technological resources and three types of complementary resources, marketing, manufacturing, and relational. We test the model using structural equation modeling on a sample of 733 Spanish manufacturing firms observed from 2003 to 2007. The data provide support for the existence of different paths to market firm technologies: an internal path, whereby the ownership of technological resources fully explains NPD performance, and an external path, whereby high intensity of marketing and relational resources reinforces the positive effect of technological resources on licensing performance. This sustains the relevance of the resource‐based value‐enhancing effects of complementary resources in licensing, as opposed to the motivation‐reducing effects advanced by transaction cost‐based literature. Moreover, the empirical analysis shows a substitution effect between NPD and licensing, whereby their simultaneous pursuit at intense levels is associated with lower profit margins. This provides evidence of the much theorized, but seldom tested, rent dissipation effect. These findings offer several contributions to research on licensing, NPD, open innovation, and the resource‐based view of the firm. On a managerial level, they suggest that achieving maximum value from proprietary technologies may not entail exploiting them both through external and internal paths. Managers are also informed that the resource combinations that enhance licensing performance include marketing and relational resources.     

中小企业对申请贷款望而却步的原因分析

笔者利用世界银行投资环境调查的数据,实证分析了中小企业有信贷需求但对申请贷款望而却步的原因。实证结果表明:规模更大、盈利性更好、成长更快的企业不太可能出现对申请贷款望而却步的情况;银企关系是影响中小企业对申请贷款望而却步的重要因素;金融生态(法治环境和诚信文化等)对于银企关系效应的发挥具有显著的促进作用。     

Does Social Media Get Your Attention?

The author investigates how social media affects stock prices and post–earnings announcement drift in response to companies’ quarterly earnings announcements. Using quarterly earnings data as well Twitter and StockTwits data, the author utilizes Twitter volume and a residual methodology to generate an attention proxy that is orthogonal to the growth of Twitter accounts. The author finds that the new attention brought by social media after the earnings announcements positively affects the cumulative abnormal returns. Further, even companies reporting bad news can still have positive immediate cumulative abnormal returns if they attract enough attention from investors after an earnings announcement. The new attention effects are different in both magnitudes and statistical significance between social media popular and unpopular industries.     

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.     

相关行业上市公司政府补助对铁路公益性补贴的启示

针对航空运输、电信、石油等国家基础设施行业,通过分析这些行业上市公司的政府补助情况,在借鉴相关行业政府补助实践的基础上,提出建立铁路公益性运输发展基金,由中央政府和地方政府共同承担铁路公益性补贴责任的政策建议,同时认为铁路运输企业除争取公益性补贴外,还应争取税收优惠、专项补贴等其他补贴政策。