Measuring Farm and Market Level Economic Impacts of Improved Maize Production Technologies in Ethiopia: Evidence from Panel Data

While it is often recognised that agricultural technology adoption decisions are intertwined and best characterised by multivariate models, typical approaches to examining adoption and impacts of agricultural technology have focused on single technology adoption choice and ignored interdependence among technologies. We examine farm‐ and market‐level impacts of multiple technology adoption choices using comprehensive household survey data collected in 2010/11 and 2012/13 in Ethiopia. Economic surplus analysis combined with panel data switching endogenous regression models are used to compute the supply shift parameter (K‐shift parameter), while at the same time controlling for the endogeneity inherent in agricultural technology adoption among farmers. We find that our improved technology set choices have significant impacts on farm‐level maize yield and maize production costs, where the greatest effect appears to be generated when various technologies are combined. The change in maize yield and production costs results in an average 26.4% cost reduction per kilogram of maize output (the K‐shift parameter). This increases the producer and consumer surpluses by US$ 140 and US$ 105 million per annum, respectively. These changes in economic surplus help to reduce the number of poor people by an estimated 788 thousand per year. We conclude that deliberate extension efforts and other policies that encourage integration of technologies are important for maize technologies to yield their full potential at both farm and market levels.     

How many factors are important in U.K. stock returns?

I use the sequential approach of Harvey and Liu ([2018]. Lucky factors (Working Paper). Duke University) to build linear factor models in U.K. stock returns among a set of 13 candidate factors using individual stocks and three groups of test portfolios between July 1983 and December 2017. My study finds that the Market factor is the dominant factor in reducing mispricing in individual stocks and test portfolios regardless of the pricing error metric used. The Market factor has a bigger impact when using a value weighting pricing error metric. Whether a second factor is used or not depends upon which metric is used for mispricing and the time period examined. My study finds support for a two-factor model for the whole sample period of the Market factor and the Conservative Minus Aggressive (CMA) factor of Fama and French ([2015]. “A five-factor asset pricing model.” Journal of Financial Economics 116: 1–22) when giving greater weight to the mispricing of larger companies.     

基于模糊多属性群决策的维护方式选择研究

维护方式选择是维护管理中的重要工作之一,合理的维护方式既能达到保障设备的稳定运行,又能同时兼顾其它各个方面的要求。由于对维护方式的评价涉及多个部门、人员和属性,有些指标只是一个模糊的概念,因而采用模糊多属性群决策的方法对维护方式进行优先抉择。本文结合A公司的设备维护方式选择问题,尝试使用模糊多属性群决策折衷算法求解最佳的维护方式。     

Supply chain capabilities for facilitating the internationalisation of retailers – a multiple case study of three Swedish retail companies

ABSTRACT

Market-oriented aspects of retail internationalisation have received a lot of research attention since the 1990s. However, beyond these aspects lies also supply-chain oriented capabilities that are necessary for retailers to successfully internationalise into foreign sales markets. By using a perspective based on resource-based theories, this paper explores supply-chain oriented capabilities that facilitate retail internationalisation. The research is based on a multiple case study of three Swedish retailers. Through the perspective of research based theories, specifically capabilities, the empirical data is studied in a single-case as well as a cross-case analysis. Findings reveal three supply chain-oriented capability categories (leadership capability, integration capability and learning capability) of importance for retail internationalisation. Resources necessary for the capabilities are to be found internally at the retailer, but also externally at other firms. This research adds to the market-oriented knowledge on retail internationalisation by adding a supply-chain oriented perspective. Further, it provides an understanding of the early phases of retail internationalisation.     

When does economic model type become a decisive factor in health technology appraisals? Learning from the expanding treatment options for relapsing–remitting multiple sclerosis

Objectives: Specific economic model types often become de facto standard for health technology appraisal over time. Markov and discrete event simulation (DES) models were compared to investigate the impact of innovative modeling on the cost-effectiveness of disease-modifying therapies (DMTs) in relapsing–remitting multiple sclerosis (RRMS). Fingolimod was compared to dimethyl fumarate (DMF; in highly active [HA] RRMS), alemtuzumab (in HA RRMS) and natalizumab (in rapidly evolving severe RRMS). Comparator DMTs were chosen to reflect different dosing regimens.

Materials and methods: Markov and DES models used have been published previously. Inputs were aligned in all relevant respects, with differences in the modeling of event-triggered attributes, such as relapse-related retreatment, which is inherently difficult with a memoryless Markov approach. Outcomes were compared, with and without different attributes.

Results: All results used list prices. For fingolimod and DMF, incremental cost-effectiveness ratios (ICERs) were comparable (Markov: £4206/quality-adjusted life year [QALY] gained versus DES: £3910/QALY gained). Deviations were observed when long-term adverse events (AEs) were incorporated in the DES (Markov: £25,412 saved/QALY lost, versus DES: £34,209 saved/QALY lost, fingolimod versus natalizumab; higher ICERs indicate greater cost-effectiveness). For fingolimod versus alemtuzumab, when relapse-triggered retreatment was included in the DES, large cost differences were observed (difference between incremental cost is £35,410 and QALY is 0.10).

Limitations: UK payer perspective, therefore societal approach was not considered. Resource utilization and utilities for both models were not derived from the subpopulations; as the focus is on model type, input limitations that apply to both models are less relevant.

Conclusions: Whilst no model can fully represent a disease, a DES allows an opportunity to include features excluded in a Markov structure. A DES may be more suitable for modeling in RRMS for health technology assessment purposes given the complexity of some DMTs. This analysis highlights the capabilities of different model structures to model event-triggered attributes.     

空间信息传输中的多天线技术综述

近年来，空间信息传输中的多天线技术得到了广泛关注和大量研究。首先介绍了多天线技术的信息论基础和演进过程；然后综述了多天线通信和雷达技术的研究进展，包括多输入多输出(Multiple-Input Multiple-Output,MIMO)卫星通信技术、深空天线组阵技术、空间多维协同传输理论与技术、MIMO雷达技术和分布式孔径相参合成雷达技术，分析了其中的关键技术及未来可研究的方向；最后，总结了多天线技术在航天测控领域应用的优势，展望了基于多天线的测控技术。     

Maximizing political vote in multiple districts

This paper models a resource allocation problem in the political context. Voters and political candidates of two parties are positioned in each of n given electoral districts. We assume that each voter will vote for the candidate he is more attracted to. This attraction is modeled by an attraction function. Each of the parties now attempts to allocate a finite budget to maximize their objective, which is either the popular vote or the number of districts, in which the party has a majority. Individual scenarios are examined with respect to leader-follower solutions and Nash equilibria. The paper then describes a dynamic model that successively allocates existing funds plus additional donations to candidates in different electoral districts.     

民营企业现金持有量影响因素研究

民营企业相对国企较少获得国家支持,其现金持有决策符合市场决策规则。将现金持有量的影响因素定位为内部财务和外部行业特征,通过回归分析,发现现金替代物、企业的银行负债、财务杠杆、企业规模与现金持有量呈负相关关系,企业的增长机会、现金流量、现金股利、激烈的行业竞争与现金持有量呈正相关关系。     

Equilibrium concepts for time‐inconsistent stopping problems in continuous time

A new notion of equilibrium, which we call strong equilibrium, is introduced for time‐inconsistent stopping problems in continuous time. Compared to the existing notions introduced in Huang, Y.‐J., & Nguyen‐Huu, A. (2018, Jan 01). Time‐consistent stopping under decreasing impatience. Finance and Stochastics, 22(1), 69–95 and Christensen, S., & Lindensjö, K. (2018). On finding equilibrium stopping times for time‐inconsistent markovian problems. SIAM Journal on Control and Optimization, 56(6), 4228–4255, which in this paper are called mild equilibrium and weak equilibrium, respectively, a strong equilibrium captures the idea of subgame perfect Nash equilibrium more accurately. When the state process is a continuous‐time Markov chain and the discount function is log subadditive, we show that an optimal mild equilibrium is always a strong equilibrium. Moreover, we provide a new iteration method that can directly construct an optimal mild equilibrium and thus also prove its existence.     

Vertical differentiation,product innovation,and dynamic competition

This paper presents an infinite horizon dynamic model in which two firms compete in a market vertically differentiated by the qualities of their products and consumers have heterogeneous preferences for quality. Given the product qualities offered, the firms engage in price competition that segments the market. In each period each firm can spend on product innovation that if successful increases the quality of its product. Three types of Markov perfect equilibria are identified. A running–coasting equilibrium exhibits increasing quality dominance with one firm undertaking innovation and the other coasting to free ride on the innovation by the first firm. The firm that coasts can have the larger dynamic payoff, so quality dominance does not imply payoff dominance. A second is a leap‐frog equilibrium in which the trailing firm undertakes innovation to leap into the lead. The trailing firm never innovates solely to narrow the gap with the leader, so catch up strategies are never used. In the third both firms undertake innovation, but if both have innovation successes, product differentiation remains the same and profits are reduced by the cost of innovation. The rivalry between Intel and AMD in microprocessors for personal computers provides a motivating example.