Variations in carambola infestation rates byBactrocera carambolae drew and hancock (Diptera: Tephritidae) with fruit availability in a carambola orchard

The relationship between the infestation rate of carambola fruits byBactrocera carambolae Drew and Hancock was investigated in a carambola orchard. Phenology of the fruits was found to influence percentage infestation of fruits byB. carambolae. The proportion of unbagged or susceptible fruits infested varied with time of year and tended to decrease with the increase of unbagged fruits available on the tree. The number of ovipunctures per fruit varied with fruit size and was also found to be indicative of the number of adult insects (B. carambolae and parasitoids) that will emerge from each fruit. Higher number of susceptible fruits available on each tree also decreased both the number of ovipunctures per fruit and the number of eggs laid per fruit, which could possibly be due to the strategy of spreading the risk adopted by the femaleB. carambolae or a result of random selection with more hosts available. The main parasitoids recorded wereBiosteres vandenboschi (Fullaway) andB. arisanus (Sonan). The mean percentage of parasitism was 38.3% and it followed roughly that of infestation of fruits.     

Maternal Employment: Does it Affect the Children When They Grow Up?

Using data on a random sample of young adults in Melbourne, this paper examines the effects of maternal employment during their childhood and adolescence on their educational attainment, relationship with their parents, premarital sexual behaviour, and attitude towards working mothers. Maternal employment has little effect on the characteristics of the son, although men whose mothers work during their adolescence were more likely to have had premarital sex than those whose mothers did not work. Maternal employment has more effect on daughters but the effects were mainly positive rather than negative.     

A Multivariate Synthetic Control Chart for Monitoring the Process Mean Vector of Skewed Populations Using Weighted Standard Deviations

This article proposes a multivariate synthetic control chart for skewed populations based on the weighted standard deviation method. The proposed chart incorporates the weighted standard deviation method into the standard multivariate synthetic control chart. The standard multivariate synthetic chart consists of the Hotelling's T ² chart and the conforming run length chart. The weighted standard deviation method adjusts the variance–covariance matrix of the quality characteristics and approximates the probability density function using several multivariate normal distributions. The proposed chart reduces to the standard multivariate synthetic chart when the underlying distribution is symmetric. In general, the simulation results show that the proposed chart performs better than the existing multivariate charts for skewed populations and the standard T ² chart, in terms of false alarm rates as well as moderate and large mean shift detection rates based on the various degrees of skewnesses.     

A new double sampling control chart for monitoring process mean using auxiliary information

Statistical quality control charts have been widely accepted as a potentially powerful process monitoring tool because of their excellent speed in tracking shifts in the underlying process parameter(s). In recent studies, auxiliary-information-based (AIB) control charts have shown superior run length performances than those constructed without using it. In this paper, a new double sampling (DS) control chart is constructed whose plotting-statistics requires information on the study variable and on any correlated auxiliary variable for efficiently monitoring the process mean, namely AIB DS chart. The AIB DS chart also encompasses the classical DS chart. We discuss in detail the construction, optimal design, run length profiles, and the performance evaluations of the proposed chart. It turns out that the AIB DS chart performs uniformly better than the DS chart when detecting different kinds of shifts in the process mean. It is also more sensitive than the classical synthetic and AIB synthetic charts when detecting a particular shift in the process mean. Moreover, with some realistic beliefs, the proposed chart outperforms the exponentially weighted moving average chart. An illustrative example is also presented to explain the working and implementation of the proposed chart.     

Double sampling |S| control chart with variable sample size and variable sampling interval

This study presents a control chart for monitoring shifts in the covariance matrix of a multivariate normally distributed process. This chart combines the double sampling, variable sample size and variable sampling interval features, and is called the DSVSSI |S| chart. A Markov chain approach is developed to design the DSVSSI |S| chart, by minimizing the average time to signal (ATS), for a specified shift size in the covariance matrix. The DSVSSI |S| chart has a better ATS performance compared to other existing charts. An example is given to illustrate the operation of the DSVSSI |S| chart.     

Physical and mental health changes in aging foster parents: Do child behavioural problems hasten declines?

This study examined foster parent physical and mental health over time. It was hypothesized that increased severity and frequency of child behavioural problems, whether externalizing or internalizing, would be associated with poorer health over time, especially for foster parents ≥60 years of age. Data from the baseline and Wave 2 interview of the 2010 National Survey of Child and Adolescent Well‐Being were used. The final analytic sample included kin and nonkin foster parents who had custody of a foster child for both waves of data collection (n = 962). Ordinary Least Squares regression models with lagged dependent variables showed that foster parents ≥60 had deteriorating physical health over time, but caregiver age alone had no association with worsening mental health. However, parents ≥60 caring for children with externalizing behavioural problems had significantly improved physical health. Mental health of parents ≥60 significantly diminished if child externalizing or internalizing problems worsened. Findings indicate that for aging foster parents, externalizing child behaviours may stimulate physical activity and improved physical health, yet any type of child behavioural problem can deteriorate mental health functioning.