On trends and constants in periodic autoregressions

Periodic autoregressions are characterised by autoregressive structures that vary with the season. If a time series is periodically integrated, one needs a seasonally varying differencing filter to remove the stochastic trend. When the periodic regression model contains constants and trends with unrestricted parameters, the data can show diverging seasonal deterministic trends. In this paper we derive explicit expressions for parameter restrictions that result in common deterministic trends under periodic trend stationarity and periodic integration.     

Determinants of Perceived Interfirm Dependence in Industrial Supplier Relations

Studies of industrial buyer-supplier relations mostly focus on structural characteristics of the transactions between parties, and assume a direct relation between these factors and characteristics of the relationships. This paper focuses on the psychological dimension of transaction relations, reflected in perceptions of dependence, from the perspective of an industrial supplier. In the first step of the analysis, three groups of structural determinants of perceived supplier dependence are explored: factors related to goal mediation, factors related to relation-specific assets, and factors related to network embeddedness. After that, the influence of these structural factors and of perceived supplier dependence on the ordering of buyer-supplier relations is investigated. Data come from a study of the micro-electronics assembly industry in the Netherlands. The findings show that sales to a particular buyer as a percentage of the total sales of the supplier and the growth of sales to a particular buyer (two forms of goal mediation) are important determinants of perceived supplier dependence. Human asset specificity is also related to perceived supplier dependence. Network embeddedness variables play only a minor role in explaining perceived supplier and buyer dependence in this study. The data further show that perceived dependence has an effect on the degree of ordering in the relationship, next to structural factors like the extendedness of the relationship beyond the focal transaction and physical asset specificity. The effects of human asset specificity and dedicated assets on ordering are contrary to what was expected on the basis of the literature.     

具体人性——人权与宽容的新维度

简要列出宽容概念的种类,并概述人权与实际(或具体)人性之间的关联以及实质性的相互关系,基于针对人权的进一步区别、历史修正以及人权阐释的发展的评论,勾勒出人权从保护性人权向供人分享和有积极创造性的人权的发展历程,并提出与标准的法定人权相比,供人分享和有积极创造性的人权是对伦理上的真正尊严的主张,是一种道德人的准权利。因此,用“具体人性”和对具体人性的实际描述真正代替仅仅沉湎于人性和人道的相当抽象的观念,这在所有的人权教育中都是最重要的。     

论1807年的现象学的逻辑

在研究黑格尔《精神现象学》的内容时,应该同时研究其体系学的形式。1807年的现象学是建立在诸逻辑基本环节的某种序列的基础上的,而这种序列与黑格尔当时的逻辑学构想是相一致的,并且在现象学内具有一种统一的功能。要弄清这些基本规定之进程,有着诸多困难。在现象学的布局中的修改并没有走到损害现象学之逻辑根基的地步。本文第一章表明,从一开始,黑格尔就提出了这一要求:在非实在的意识的方式与逻辑的环节之间要有一种严格的对应。第二章讨论这些逻辑的环节作为什么进入意识的经验当中,以及它们如何组织意识的经验。第三章具体说明这些逻辑的基本环节的序列及其同意识的诸阶段的对应。文章最后还把一种有关现象学的方法和有关耶拿逻辑学的发展的见解,提出来进行了讨论。     

Homosexual role separation: Implications for analyzing and modeling the spread of HIV

The analysis of the spread of HIV in homosexual populations must be based on knowledge of all factors which promote or inhibit transmission. Recently, data were reported from the Amsterdam cohort study that imply that sexual role separation and the changes therein should be taken into account in analyzing and modeling the spread of HIV. In this paper, a role separation mixing model is described and linked to data from the Amsterdam cohort. The model allows one to study the impact of homosexual role separation on the spread of HIV. The homosexual men are classified into four sexual subgroups based on the preference for: 1) no anal intercourse; 2) anal insertive only; 3) anal receptive only; 4) both insertive and receptive. The analysis accounts for variability and change in homosexual role behavior and loss to follow up. The results support the conjecture that there are large differences between the risks of receptive and insertive anal intercourse, with the latter carrying only minimal risk. The analysis indicates that the spread of HIV is mostly restricted to subgroup 4, the largest and sexually most active subgroup. In this subgroup, the estimated probability of HIV transmission from an infected insertive partner (in subgroup 2 or 4) to a receptive susceptible (in subgroup 4) is between 1 and 5 percent (assuming a closed cohort).     

Birth order effects on young students’ academic achievement

We examine birth order effects on academic achievement for ten-year-old students using data for the entire population of fifth graders in Norway 2007/2008. The analysis thus adds to a thin empirical literature focusing on birth order effects among young children. We find that being firstborn confers a significant advantage in families with two, three and four children. The analysis makes two other contributions. First, we provide evidence that unless mother's age at childbirth is included among the control variables, only small and imprecise birth order effects are revealed in families with low socioeconomic status. Second, we provide some evidence that the birth order effects differ across families with highly educated and less educated mothers, which lend support to the resource dilution model over the confluence model.     

On trends and constants in periodic autoregressions

Periodic autoregressions are characterised by autoregressive structures that vary with the season. If a time series is periodically integrated, one needs a seasonally varying differencing filter to remove the stochastic trend. When the periodic regression model contains constants and trends with unrestricted parameters, the data can show diverging seasonal deterministic trends. In this paper we derive explicit expressions for parameter restrictions that result in common deterministic trends under periodic trend stationarity and periodic integration.     

Pitfalls in multi-national long-range planning

The authors of this article argue that too many companies are not getting the benefits which should be produced by their long-range planning systems. Of the many possible explanations for this, the authors concentrate on the major pitfalls which should be avoided in order to ensure good results. The article is based upon the results of a survey of planning pitfalls among corporations in six industrialized countries.     

Crisis in rural life and crisis in thinking: directions for critical research*

La crise contemporaine de la vie rurale et agricole c'est produite simultanément avec une crise de la pensée et de la recherche critique: une analyse basée sur l'engagement à créer une société plus rationelle, démocratique et égalitaire. L'économie politique, le paradigme prédominant, a contribuée de façon importante à l'identification et à l'analyse des méchanismes économiques sur lesquels se développent la crise sociale. Mais celui-ci n'a tenu aucun compte d'enquêter sur la façon dont une crise est vécue par ceux qui en sont le plus touchés, et sur les perspectives de changement queue crise du genre peut offrir. Ceci est due d'un côtéà la nature des hypothèses théoriques de l'économie politique, ainsi que sur la façon dont les économistes politiques utilisent les méthodes des sondages dans leurs travaux empiriques. En utilisant les ressources offertes par la theorie sociale et les résultats de recherche primaire et empirique, cet article suggère de nouvelles directions pour la recherche critique de la vie rurale. Nous expliquons que ce genre de recherche devrait devenir plus hermaneutique et phénoménologique dans le but de concentrer sur les perceptions, l'analyse personnelle et les activités de ceux qui vivent dans les milieux ruraux, surtout lorsque ceux-ci essaient de préserver leurs communautés contre l'influence de l'extérieur. II n'est plus nécessaire, de présumer que les chercheur(e)s et leur sujets doivent demeurer détachés si la recherche est sérieusement scientifique et érudite. Cet article considère certaines implications théoriques, empiriques et historiques qu'apporte cet argument. The contemporary crisis in agriculture and rural life has been paralleled by a crisis in critical thinking and research: analysis informed by the commitment to a more rational, democratic and egalitarian society. Political economy, the currently dominant critical paradigm, has made important contributions to the identification and analysis of the economic mechanisms through which social crisis develops. But it has by and large failed to probe both the ways in which crisis is actually experienced by people enduring it and the real possibilities for change that a crisis situation might offer. This failure stems both from the nature of the theoretical assumptions which inform political economy and the manner in which political economists deploy methods of survey research in their empirical work. Using both the resources of social theory and the results of empirical, primary research, this paper attempts to suggest new directions for critical research into rural life. J t argues that this research should adopt a more explicitly hermeneutical and phenomenological focus which should put the perceptions, self-understandings and activities of rural people themselves, particularly as they strive to preserve their communities against outside forces, more fully at the centre of analysis. No longer should it be assumed that researchers and those studied must remain separate if research is to be truly scholarly and scientific. The paper addresses some possible theoretical, empirical and historical     

Dynamic Pricing to Minimize Maximum Regret

We consider a dynamic pricing problem that involves selling a given inventory of a single product over a short, two‐period selling season. There is insufficient time to replenish inventory during this season, hence sales are made entirely from inventory. The demand for the product is a stochastic, nonincreasing function of price. We assume interval uncertainty for demand, that is, knowledge of upper and lower bounds but not a probability distribution, with no correlation between the two periods. We minimize the maximum total regret over the two periods that results from the pricing decisions. We consider a dynamic model where the decision maker chooses the price for each period contingent on the remaining inventory at the beginning of the period, and a static model where the decision maker chooses the prices for both periods at the beginning of the first period. Both models can be solved by a polynomial time algorithm that solves systems of linear inequalities. Our computational study demonstrates that the prices generated by both our models are insensitive to errors in estimating the demand intervals. Our dynamic model outperforms our static model and two classical approaches that do not use demand probability distributions, when evaluated by maximum regret, average relative regret, variability, and risk measures. Further, our dynamic model generates a total expected revenue which closely approximates that of a maximum expected revenue approach which requires demand probability distributions.