Ordering,Pricing, and Lead‐Time Quotation Under Lead‐Time and Demand Uncertainty

In this article, we study the newsvendor problem with endogenous setting of price and quoted lead‐time. This problem can be observed in situations where a firm orders semi‐finished product prior to the selling season and customizes the product in response to customer orders during the selling season. The total demand during the selling season and the lead‐time required for customization are uncertain. The demand for the product depends not only on the selling price but also on the quoted lead‐time. To set the quoted lead‐time, the firm has to carefully balance the benefit of increasing demand as the quoted lead‐time is reduced against the cost of increased tardiness. Our model enables the firm to determine the optimal selling price, quoted lead‐time, and order quantity simultaneously, and provides a new set of insights to managers.     

The Uniform-Laplace Distribution and the D-Test

A new two-sample rank test for location is proposed. This test, called the D-test, is asymptotically efficient for underlying densities which follow a “flat-topped” Laplace distribution. The D-statistic is simple to compute, and the test may be suitable when there is censoring. The D-test includes the median test as a special case.     

On the practical application of mixed effects models for repeated measures to clinical trial data

The use of mixed effects models for repeated measures (MMRM) for clinical trial analyses has recently gained broad support as a primary analysis methodology. Some questions of practical implementation detail remain, however. For example, whether and how to incorporate clinical trial data that is collected at nonprotocol‐specified timepoints or clinic visits has not been systematically studied. In this paper, we compare different methods for applying MMRM to trials wherein data is available at protocol‐specified timepoints, as well as nonprotocol‐specified timepoints due to patient early discontinuation. The methods under consideration included observed case MMRM, per protocol visits MMRM, interval last observation carried forward (LOCF) MMRM, and a hybrid of the per protocol visits and interval LOCF MMRM approaches. Simulation results reveal that the method that best controls the type I error rate is the per protocol visits method. This method is also associated with the least precision among the competing methods. Thus, in confirmatory clinical trials wherein control of type I error rates is critical, per protocol visits MMRM is recommended. However, in exploratory trials where strict type I error control is not as critical, one may prefer interval LOCF MMRM due to its increased precision. Points to consider with respect to both study design (e.g., assigning schedule of events) and subsequent analysis are offered. Copyright © 2012 John Wiley & Sons, Ltd.     

From ‘What the F#@% is a Facebook?’ to ‘Who Doesn’t Use Facebook?’: The role of criminal lifestyles in the adoption and use of the Internet

Concerns about a digital divide persist and recent calls have been made for understanding how lifestyles influence Internet adoption and use. Online criminal behaviors have drawn attention from law enforcement, but diffusion of innovation theory suggests higher propensities for crime, particularly street crime, reduces the likelihood of Internet use. Drawing from this theory and research on the role of street criminal lifestyles on technology adoption, this study examined patterns of Internet use among a sample of 585 individuals at-risk for and involved in street crime. Results from our logistic and negative binomial regression analyses lead to two general conclusions: (1) compared to research on the general population, similar predictors and lower rates of Internet participation and usage are observed, and (2) mixed evidence suggests participation in criminal lifestyles contributes to digital inequality. The results support a theory of technological diffusion to marginalized populations. We conclude by discussing the expansion of technology, digital inequality, and crime.     

赫拉克利特、巴门尼德、老子与万物的统一

本文首先区分了赫拉克利特和巴门尼德关于对立统一的两种思路：前者认为对立面的统一就在对立面本身之中,后者认为对立面的统一在对立的双方之外、超越对立而存在。由此出发,作者探讨了柏拉图和老子关于对立统一的思想。通过对这些思想的比较,指出关于对立统一的形而上学问题已经触及理性思考的边界,并且正是因此始终具有思想上的活力。     

Making the Housing Unit Method Work: An Evaluation of 2010 Population Estimates in Florida

The housing unit (HU) method—in which population estimates are derived from estimates of occupied HUs—is the most commonly used method for making small-area population estimates in the United States. It is widely used because it is conceptually simple, can utilize a wide variety of data sources, can be applied at virtually any level of geography, and often produces reliable estimates. Yet the HU method is more nearly a general approach to population estimation than it is a specific methodology. In this paper, we describe and evaluate several data sources and estimation techniques that can be used in applying the HU method. Using a set of county and subcounty estimates produced by the Bureau of Economic and Business Research (BEBR) at the University of Florida for April 1, 2010, we analyze errors by population size and growth rate, calculate errors for each of the three components of the HU method, and investigate the accuracy of estimates based on several different data sources and estimation techniques. We compare the accuracy of the 2010 estimates with previous BEBR estimates and estimates produced by the U.S. Census Bureau. We conclude that although some data sources and estimation techniques work better than others, the HU method can be tailored to produce reliable population estimates for a wide variety of geographic areas.     

Perceived Social Support and School Well-Being Among Chinese Early and Middle Adolescents: The Mediational Role of Self-Esteem

This study examined the mediational role of self-esteem in accounting for the empirical link between perceived social support (parents, friends, and teachers) and school well-being (school satisfaction, positive affect in school, and negative affect in school). Participants were from China and were 221 early adolescents (Mage = 13.6) and 140 middle adolescents (Mage = 16.4). Among early adolescents, parent and teacher support, but not friend support, related significantly to positive school well-being. Among middle adolescents, friend and teacher support, but not parent support, significantly related to school well-being. For both early and middle adolescents, global self-esteem mediated relations between teacher support and school well-being. For early adolescents, global self-esteem mediated relations between parent support and school well-being; whereas for middle adolescents, global self-esteem mediated relations between friend support and school well-being. The findings supported socialcognitive models of well-being in Chinese context. Implications are discussed in the context of developmental and cultural considerations.