Does corporal punishment erode the quality of the mother–child interaction in early childhood?

Corporal punishment is believed to exert its influence partially on children's externalizing behavior by undermining the quality of parent‐child relationships, but empirical evidence for this belief is lacking. Thus, the goal of this study was to explore longitudinally whether the use of corporal punishment by mothers was associated with declining quality in parent‐child interactions and whether these declines mediated the links between corporal punishment and later externalizing behavior. Based on data from the NIHCD SECCYD, the findings from this study indicated that the links between the quality of parent‐child interaction and corporal punishment were bidirectional: high quality parent‐child interaction was associated with less use of subsequent corporal punishment by mothers, and maternal use of corporal punishment at 36 months was associated with declines in the quality of parent‐child interaction at 54 months. There were not significant indirect effects of corporal punishment at 36 months on grade 3 aggression through 54 month parent‐child interaction quality, however, which suggests other mechanisms might account for the links between early corporal punishment and later externalizing problems.     

Combinatorial analysis for route first-cluster second vehicle routing

Two Route first-cluster second vehicle routing algorithms are contrasted in the first section of the paper. Next, the ‘large’ number of feasible solutions to a multiple travelling salesman problem is established given that each salesman can visit any number of customers in a stated range. An approximate expression is given for the ‘small’ fraction of this solution space searched by a route first-cluster second vehicle routing heuristic. Nevertheless, this heuristic is seen to be a very efficient means of searching its solution space.     

Comparing products using data envelopment analysis

Using an application of linear programming known as Data Envelopment Analysis (DEA), a method is described to compare products which vary in excellence along a number of dimensions, and for each of which there might be a number of associated “costs”. The method is illustrated by comparing published benchmarks of 37 computer printers. Potential uses of a DEA analysis of products might be: to assist corporate buyers who may need to reconcile a diversity of present and future uses in one standardised purchase; in competitor analysis; in determining unexplored market niches; and as a normative model of product excellence against which product purchasing behaviour could be compared.     

Inventory control in hospital blood banks

The delicate relationship between donors and the Transfusion Service in the U.K. implies a clear duty to make the best possible use of the limited blood supplies, and this turns attention upon the stocking policies adopted by Hospital Blood Banks. Whereas Blood Bank staff can obtain an intuitive grasp of the effects of various stock levels for the common bloods, this is not usually the case for the rare bloods which are more difficult to control. A policy decision has to be made which balances the conflicting stock requirements of maintaining a high availability and also low out-dating rates. A Markovian structure is exploited in this paper for this purpose and the effects of the key variables are shown to be interrelated. In any particular instance the form of the probability distribution of demand between replenishments, the scale of the throughput, the blood life in relation to the ordering interval, the fraction of blood transfused and the fraction of the replenishment order which is supplied to the Bank will together determine the form of the operating characteristics.