POTENTIAL COMPETITION AND POSSIBLE COLLUSION IN FOREST SERVICE TIMBER AUCTIONS

Potential competition significantly affects the size of winning bids in Forest Service sealed-bid timber auctions and has little effect on winning bids in oral auctions. Winning sealed bids depend even more, however, on actual competition, a result suggesting collusion. This explanation is supported using an index representing the likelihood an auction was rigged. Preclusive bidding (a type of collusion) in oral auctions is indicated by a positive relationship between hauling distances and the size of winning sealed bids. Comparisons of winning-bid variances, overbids, and numbers of bidders across auction type support this explanation of oral auction prices.     

The Future of Environmental Justice Research: A Response to Gould and Weinberg

Sociological Forum -     

Determination of recovery effort for a probabilistic recovery system under various inventory control policies

In this study we investigate the desired level of recovery under various inventory control policies when the success of recovery is probabilistic. All the used and returned items go into a recovery process that is modelled as a single stage operation. The recovery effort is represented by the expected time spent for it. The effect of increasing recovery effort on the success probability together with unit cost of the operation is included by assuming general forms of dependencies. Alternative to recovered items, demand is satisfied by brand-new items. Four inventory control policies that differ in timing of and information used in purchasing decision are proposed. The objective is to find the recovery level together with inventory control parameter that minimize the long-run average total cost. A numerical study covering a wide range of system parameters is carried out. Finally computational results are presented with their managerial implications.     

Local Governments Connecting to the Global Economy: Globalization as Catalyst in Governance of East African Cities

This article responds to two questions: first, how are large local governments in East Africa responding to the emerging global economy? Second, is globalization a catalyst in enhancing local governance in Nairobi, Kampala, and Dar es Salaam? The paper is an empirical analysis of strategies adopted by local government organizations in search of meeting challenges brought by a globalization. While there are some similarities in the strategies and processes adopted, the implementation pace varies across the three organizations. At the end, an attempt is made to explain these differences.     

南充市城区已婚育龄妇女二孩生育意愿研究

2018年4—5月在四川省南充市城区采用便利抽样,以已婚且未育或已育一个小孩的育龄妇女为研究对象,采用自制匿名问卷,以面对面的形式收集资料,了解实施全面二孩政策后南充市育龄妇女的生育意愿,为南充市的人口研究提供参考依据。在213名调查对象中,56人(26.3%)有二孩生育意愿,140人(65.7%)无二孩生育意愿,17人(8.0%)不确定是否生育二孩。南充市被调查者的理想子女个数均值为1.46,意愿子女个数均值为1.27。不同文化程度(χ2=7.512)、配偶月收入(χ2=12.641)、理想子女数(χ2=66.401)、一孩性别(χ2=5.441)的育龄妇女间二孩生育意愿差异有统计学意义(P<0.05)。Logistic回归分析显示,第一个孩子性别为女孩(OR=2.641,P=0.021)、丈夫月收入越高(OR=1.761,P=0.028)、理想子女数多于1个(OR=29.040,P<0.001)的育龄妇女更有意愿生育二孩。南充市城区二孩生育意愿处于较低水平,经济收入、理想子女数、一孩性别会影响育龄妇女的二孩生育意愿。全面二孩政策对于促进育龄妇女生育二孩的效应有限,应当建立相关的配套政策,以促进全面二孩政策的实施。     

The FastHCS algorithm for robust PCA

Principal component analysis (PCA) is widely used to analyze high-dimensional data, but it is very sensitive to outliers. Robust PCA methods seek fits that are unaffected by the outliers and can therefore be trusted to reveal them. FastHCS (high-dimensional congruent subsets) is a robust PCA algorithm suitable for high-dimensional applications, including cases where the number of variables exceeds the number of observations. After detailing the FastHCS algorithm, we carry out an extensive simulation study and three real data applications, the results of which show that FastHCS is systematically more robust to outliers than state-of-the-art methods.     

Housing and children: simultaneous decisions?—a cohort study of young adults’ housing and family formation decision

This study contributes to earlier research on homeownership and childbearing by taking into account the potential simultaneity between these two life events. A dataset comprising three different Swedish birth cohorts suggests that these are events that are indeed simultaneous. Different tests indicate that taking this simultaneity into account gives an overall statistically significant improvement of the model fit. However, this result is most obvious for those young adults who faced increasing problems on the housing market. The childbearing decision of these cohorts also seems to be more sensitive to changes in the user cost.