Household Tree Planting in Tigrai,Northern Ethiopia: Tree Species,Purposes, and Tenure Security

Trees on farms have multiple roles in rural livelihoods, providing significant economic and ecological benefits. Trees on farms also constitute vital components in mixed crop-livestock-tree systems. In this paper, we analyze household tree planting and tenure security and explore the most important determinants that enhance the propensity to plant trees, using a cross-sectional household-level dataset from a sample of 200 households in the highlands of Tigrai, northern Ethiopia. Specifically, we employ a sample selection model that simultaneously takes into account the two decisions of tree growers (whether or not to plant tree and how many) to analyze the effect of tenure security on tree planting. We also use a multinomial logistic regression model to analyze the most important determinants contributing to a household’s decision of planting of particular tree species. We find that, among other things, tenure security enhances the propensity to plant trees as well as the amount of tree planting. Findings also suggest that households consider a diversity of attributes in making decisions to plant specific trees. These results can be used by policymakers to promote on-farm and homestead tree cultivation of private households in the study area by strengthening tenure security and considering households’ choices of specific tree species based on their attributes.     

基于熵权—理想解法的城市复合系统资源环境承载力时空分异研究

区域协调发展是科学发展的重要内涵,科学评价承载力对协调发展具有重要的理论和现实意义。运用熵权—理想解法,并基于空间分析模型,探讨福建省9个地级以上城市资源环境承载力范围以及时空格局演变特征,结果表明:(1)从时间序列角度分析,厦门市承载力处于良好承载状态,其余地市处于波动向好状态;(2)各子系统承载力处于波动状态,不同地市子系统承载力存在较大差异;(3)区域复合系统承载力在全局空间分布上不存在显著的正自相关关系,局域空间上仅泉州市复合系统承载力与周边地区存在集聚效应。根据空间格局热点演化趋势,资源环境承载力局部空间分异明显。因此,在数字经济发展背景下,在高质量发展的同时,更应做到区域协同发展,从而推动复合系统环境承载力水平的提高。     

Brand protection across the enterprise: Toward a total-business solution

Though counterfeit products pose a large and growing problem, brand owners may not always respond effectively. Corrective efforts may be scattered or reactive, with some brand owners not even recognizing the problem. Previous research has indicated a total-business solution, involving virtually all functions of the enterprise, can help address the problem in a more systematic and effective way. To better identify what a total-business solution might look like, we asked a sample of 42 respondents—33 brand-protection practitioners and nine other respondents with academic, service, or other perspectives—to identify all functions and tactics that might be associated with brand-protection efforts. Altogether, respondents identified 38 functions associated with 757 unique tactics among more than 1,300 total tactics. Using these data, we assessed the depth and breadth of each function. We also identified multiple functions that can together support a total-business solution, and our results can help managers engage these functions to protect their brands. Future work may gauge the extent to which firms actually incorporate these functions as well as how managers consider the value, breadth, and depth of each function in relation to their organizations.     

设计方案优劣群体决策法

在国民经济建设中，常对某些专家提出的设计方案，按着某些特性，从各不相同的特性指标优先次序出发，得到群体优先次序。其中Ｂｏｒｄａ数最大者便是最优方案。     

The average number of events per time unit and its estimation

Let ζ _t be the number of events which will be observed in the time interval [0;t] and define as the average number of events per time unit if this limit exists. In the case of i.i.d. waiting-times between the events,E[ζ _t ] is the renewal function and it follows from well-known results of renewal theory thatA exists and is equal to 1/τ, if τ>0 is the expectation of the waiting-times. This holds true also when τ = ∞.A may be estimate by ζ _t /t or where is the mean of the firstn waiting-timesX ₁,X ₂, ...,X _n . Both estimators converage with probability 1 to 1/τ if theX _i are i.i.d.; but the expectation of may be infinite for alln and also if it is finite, is in general a positively biased estimator ofA. For a stationary renewal process, ζ _t /t is unbiased for eacht; if theX _i are i.i.d. with densityf(x), then ζ _t /t has this property only iff(x) is of the exponential type and only for this type the numbers of events in consecutive time intervals [0,t], [t, 2t], ... are i.i.d. random variables for arbitraryt > 0.     

Why H does not measure information: the role of the “special case” legerdemain solution in the maintenance of anomalies in normal science

Anomalies or contradictions threaten a paradigm, and if they cannot be ignored, they must be either shown to be false, or must be resolved. Two common anomalies in the systems literature are examined: the contention that H measures information; and the contention that heat increase leads to entropy increase. It is shown that when faced with such anomalies, paradigm adherents often resort to legerdemain solutions, which appear to resolve the anomaly, either verbally or mathematically. Legerdemain solutions generally utilize special cases such as maximum or minimum values or equilibrium conditions, and will not hold for the general case. Thus they do not resolve the anomaly, but only appear to (hence the name legerdemain). It is shown further that legerdemain solutions are often responses to anomalies which are not major contradictions, but are rather the result of confusion in second-order or meta-paradigms. The satisfactory solution lies not in an appeal to a legerdemain solution, but in adherence to the consistent general principles of the primary paradigm, even if this necessitates some revision of terminology or principles in the secondary paradigm.     

Axiomatic approach to approximate solutions in multiobjective optimization

An axiomatic approach is introduced in order to study the approximate solution map of a vector optimization problem in the image space. We investigate the possibility to formulate an appropriate notion of approximate solutions that is compatible with von Neumann–Morgenstern utility theory. An impossibility result is proved in the sense that, whenever all of the axioms are satisfied, either the set of the approximate solutions is a subset of the exact solutions of the problem, or it coincides with the whole admissible set. Moreover, the geometry of the approximate solution map is studied in some special cases.      

An empirical application of the EVA® framework to business cycles

Following financial concepts like duration and economic value added (EVA®) we estimate the impact of interest rate movements on firms that are more and less roundabout. We find that firms that are more roundabout, that is, work with expected cash-flows with higher duration, are more sensitive to interest rate movements. To the extent that monetary policy is able to move the discount rate used by investors, monetary policy changes the relative present value of any investment project and therefore affects resource allocation. We show evidence that this effect is present in the U.S. in the years prior to the subprime crisis.     

甲甲酯装置生产瓶颈酰胺加热器的技术改造分析

本文重点介绍了哈氏合金设备W503在甲甲酯装置的应用问题与腐蚀、技术改造,通过对于出现的问题及其原因进行具体的分析,逐步改革和完善技术改革与固溶处理方案,本研究对于促进甲甲酯装置生产瓶颈酰胺加热器的技术改造具有重要的参考价值和实际意义。