Indirect evidence of the contribution of prenatal sex selection practices to the high sex ratio at birth in Vietnam

This paper reports indirect evidence that prenatal sex selection is a contributor to the recent increase in sex ratio at birth in Vietnam. The paper uses birth data from the Population Change Survey 2006 to assess the associations between sex ratio at birth and variables that predict increased opportunities to practise prenatal sex selection, including maternal knowledge of foetal sex before birth, the use of ultrasound for foetal sex determination, the gestation week when foetal sex was disclosed, and access to abortion services. The high sex ratio of most recent births was significantly associated with the use of ultrasound to determine the foetal sex in gestation weeks 12–22 and with access to family planning services that provide abortion. Prenatal sex selection in health facilities are likely to contribute to the recent increase in sex ratio at birth in Vietnam.     

A scale-location adjustment for proportional hazards deviance residuals

We show that deviance residuals derived using the proportional hazards assumption (including Cox regression) are not asymptotically standard normal, but that a scale-location adjustment makes them nearly standard normal, even for moderate sample sizes. This adjustment should aid in outlier detection, as it allows a more exact assessment of when a deviance residual is unusually large.     

Independent dominating sets in triangle-free graphs

The independent domination number of a graph is the smallest cardinality of an independent set that dominates the graph. In this paper we consider the independent domination number of triangle-free graphs. We improve several of the known bounds as a function of the order and minimum degree, thereby answering conjectures of Haviland.     

Maximum and Minimum Prediction Variance for Spherical and Cuboidal Split Plot Designs

The impact of restricted randomization on the information matrix has created challenges for the computation of design optimality criteria. This article focuses on the computation of the maximum and minimum prediction variance for Central Composite (CCD) and Box–Behnken (BBD) split plot designs (SPD). The approach is to analytically determine the exact maximum and minimum prediction variance for both spherical and cuboidal second-order SPD. A particular feature of these analytical functions is that they are functions of the design parameters. Finally, the application of these analytical functions is demonstrated for a CCD SPD.     

Conflicts over farming practices in Canada: the role of interactive conflict resolution approaches

An increasing number of articles in professional and scientific journals, as well as in the public press, give evidence to a rising number of conflicts that exist in rural communities. These conflicts arise from changes in farming practices, the increasing number of large-scale production units, resource use, and demographics. Fair, effective and efficient approaches to resolve these conflicts are of increasing interest and importance. An interactive conflict resolution (ICR) approach that focuses on communication and positive social interactions may be a preferred approach for resolving conflicts. The role of ICR approaches in addressing conflicts arising from farming and agri-business practices is presented and discussed in this paper. The paper posits that ICR approaches are efficient from an economic as well as a social perspective and that they provide the greatest potential to realize socially optimal outcomes from a both a theoretical and practical perspective.     

Estimation of the sum of differences distribution

Consider the distribution of Z_i d_iwhere the d.d_i?s are 1=1 lldifferences independently, identically and symmetrically distributed with mean zero. The problem is to determine properties of the sdd given the distribution of the d._i?fs and the sample size n. The standardized moments as a function of the moments of the d._i!s are developed. A variance reduction technique for estimating the quantiles of the sdd using Monte Carlo methods is developed based on using the randomization sample consisting of the 2ⁿ values of Z _i+d. rather than the single observation i=l lZ d. corresponding to each sample d_id_n. The randomization sample is shown to produce unbiased and consistent estimators.     

Phased local search for the maximum clique problem

This paper introduces Phased Local Search (PLS), a new stochastic reactive dynamic local search algorithm for the maximum clique problem. (PLS) interleaves sub-algorithms which alternate between sequences of iterative improvement, during which suitable vertices are added to the current clique, and plateau search, where vertices of the current clique are swapped with vertices not contained in the current clique. The sub-algorithms differ in their vertex selection techniques in that selection can be solely based on randomly selecting a vertex, randomly selecting within highest vertex degree or randomly selecting within vertex penalties that are dynamically adjusted during the search. In addition, the perturbation mechanism used to overcome search stagnation differs between the sub-algorithms. (PLS) has no problem instance dependent parameters and achieves state-of-the-art performance for the maximum clique problem over a large range of the commonly used DIMACS benchmark instances.     

Changes in Management Ownership and the Valuation Effects of Equity Offerings

Seasoned equity issues trigger share price declines, and this is usually interpreted as evidence of signalling. We find that seasoned equity issues also typically result in much lower managerial ownership in U.S. firms. Jensen and Meckling (1976) predict a stock price decline when managerial ownership falls. We conduct several tests to distinguish agency explanations form signalling explanations, and conclude that both effects are present.