Fractional Price Matching Policies Arising from the Ocean Freight Service Industry

We consider a situation in which shippers (customers) can purchase ocean freight services either directly from a carrier (service provider)in advance or from the spot market just before the departure of an ocean liner. The price is known in the former case, while the spot price is uncertain ex‐ante in the latter case. Consequently, some shippers are reluctant to book directly from the carrier in advance unless the carrier is willing to “partially match” the realized spot price when it is lower than the regular price. This study is an initial attempt to examine if the carrier should bear some of the “price risk” by offering a “fractional” price matching contract that can be described as follows. The shipper pays the regular freight price in advance; however, the shipper will get a refund if the realized spot price is below the regular price, where the refund is a “fraction” of the difference between the regular price and the realized spot price. By modeling the dynamics between the carrier and the shippers as a sequential game, we show that the carrier can use the fractional price matching contract to generate a higher demand from the shippers compared to no price matching contract by increasing the “fraction” in equilibrium. However, as the carrier increases the “fraction,” the carrier should increase the regular price to compensate for bearing additional risk. By selecting the fractional price matching contract optimally, we show that the carrier can afford to offer this price matching mechanism without incurring revenue loss: the optimal fractional price matching contract is “revenue neutral.”     

Properties of doubly-truncated gamma variables

The truncated gamma distribution has been widely studied, primarily in life-testing and reliability settings. Most work has assumed an upper bound on the support of the random variable, i.e. the space of the distribution is (0,u). We consider a doubly-truncated gamma random variable restricted by both a lower (l) and upper (u) truncation point, both of which are considered known. We provide simple forms for the density, cumulative distribution function (CDF), moment generating function, cumulant generating function, characteristic function, and moments. We extend the results to describe the density, CDF, and moments of a doubly-truncated noncentral chi-square variable.     

Domestic violence: a priority in child protection in New South Wales,Australia?

Over the last several years there has been increasing awareness of the connection between domestic violence and child abuse, yet only minimal attention has been paid to the implications of this for child protection practice. This article begins to address this gap. Drawing on research undertaken in New South Wales (NSW), Australia, it examines child protection practice in relation to children and young people who have been exposed to domestic violence. The research involved analysis of the responses of the statutory child protection authority in NSW (the Department of Community Services or DoCS) to abuse allegations involving domestic violence. The data are drawn from observation and analysis of the initial responses to referrals to DoCS and the ‘tracking’ of a sample of these referrals over an 18 month period. From the data obtained, it is evident that domestic violence referrals are treated less seriously than other referrals, with more being confirmed as abuse but fewer resulting in follow up or intervention. The implications of this for child protection practice are teased out. Copyright © 2007 John Wiley & Sons, Ltd.     

Beyond bifurcation: Examining the conventions of organic agriculture in New Zealand

The last 10 years have witnessed numerous attempts to evaluate the merits of new theoretical approaches – ranging from Actor Network Theory to ‘post-structural’ Political Economy and inhabiting a ‘post-Political Economy’ theoretical space – to the explanation of global agricultural change. This article examines Convention Theory (CT) as one such alternative approach, assessing its potential in the context of ongoing change within commercial organic agriculture in New Zealand. More specifically, CT is used to expose the insufficiency of recent ideas of conventionalisation and bifurcation, both reflecting more traditional Political Economic approaches, as explanatory concepts for the emerging condition of the New Zealand organic sector. In this paper, the concept of worlds of justification as developed in CT is utilised to address the emerging complexity of organic production. While farmers supplying a more diversified domestic market can be distinguished from those supplying export markets, an exclusive focus on such distinctions ignores the influential role of extra-economic factors on the viability of organic production systems. Thus, in addition to what are classified as market and industrial worlds in CT, the paper addresses aspects of civic, green, domestic, inspired and renown worlds. Producers' selections of organic certification organisations are used to demonstrate the interaction of these worlds in the development of the organic sector in New Zealand. The article concludes with the imperative to move ‘beyond bifurcation’ and acknowledge the greater complexity of negotiated outcomes that might be achieved from a CT perspective than from existing political economy-derived models like conventionalisation and bifurcation.     

Serial correlation and distributions on the shere

Estimation and tests for serial correlation in recation and regression models with normal error have been derive from various points of view; for example: Anderson (1948), Durbi for Watson (1950, 1951, 1971), Theil (1965), Durbin (1970), Haq (1970), Kadiyala (1970), Abrahamse & Louter (1971), Levenbac (1972), Berenblut & Webb (1973), Phillips & Harvey (1974), a Sims (1975). In this paper we derive likelihood functions and most powerful tests for serial correclation in Locationa and regression models with arbitrary but specificed error; the methods extend to include the determination of the likelihood for the parameter of the error distribution.

In Section 2, we survey the modthods that have been used in deriving the various tests and estimates in the literature. In Section 2, we introduce the stataistical model that directly describes the error distribution and we obtain the likelihood function for error correlation and determine locally and specifically kost powerful tests for correlation. In Section 3 we consider the case with normal error derive a normal distribution on the sphere by radial projection. The likelihood function and test are then specialized to the case of normal error in Section 4. The computational procedures for the tests and related power functions are examined in Section 5. Power comparisons for the textile data of Theil and Nagar (1961), the consumption data of Kelin (1950), and the plums and the wheat data of Hildreth & Lu (1960) are presented in Section 6, while the likelihood functions for correlation in these data are given in Section 7.     

The effects of welfare and child support policies on union formation

We use data from a new longitudinal survey – the Fragile Families and Child Wellbeing Study – to examine how welfare and child support policies, and local labor market conditions, affect union formation among unmarried parents who have just had a child together. We use multinomial logistic regression to estimate the effects of the policy variables along with economic, cultural/interpersonal, and other factors on whether (relative to being in a cohabiting relationship) parents are not romantically involved, romantically involved living apart, or married to each other about one year after the child's birth. We find that – contrary to some previous research – higher welfare benefits discourage couples from breaking up, while strong child support enforcement reduces the chances that unmarried parents will marry; local unemployment rates do not appear to be strongly associated with union formation decisions after a nonmarital birth.     

Hierarchical related regression for combining aggregate and individual data in studies of socio-economic disease risk factors

Summary.  To obtain information about the contribution of individual and area level factors to population health, it is desirable to use both data collected on areas, such as censuses, and on individuals, e.g. survey and cohort data. Recently developed models allow us to carry out simultaneous regressions on related data at the individual and aggregate levels. These can reduce 'ecological bias' that is caused by confounding, model misspecification or lack of information and increase power compared with analysing the data sets singly. We use these methods in an application investigating individual and area level sociodemographic predictors of the risk of hospital admissions for heart and circulatory disease in London. We discuss the practical issues that are encountered in this kind of data synthesis and demonstrate that this modelling framework is sufficiently flexible to incorporate a wide range of sources of data and to answer substantive questions. Our analysis shows that the variations that are observed are mainly attributable to individual level factors rather than the contextual effect of deprivation.