Effects of Posture on Newborn Crying

Acoustic properties of the cries of 14 infants were evaluated at both 2 and 4 weeks of age when the infants were lying in a supine position and when they were sitting upright in a car seat. In the upright position, infants' breathing was more rapid and showed less individual variability. The fundamental frequency of their cries increased in the upright position, but this increase was likely attributable to increased arousal or distress, not to posture per se. There were no differences in acoustic measures related to vocal tract shape in the supine versus upright positions. Across age, there was a decline in fundamental frequency. Individual difference stability of most acoustic measures was moderate to high. The importance of postural effects on the acoustic features of cries was discussed.     

Men together: understanding the gay couple

The present study surveyed male gay couples to determine how their relationships began and were maintained, the types of conflict they experienced, and how the issues of monogamy, sexual behavior and AIDS affected the relationships. Ninety-two couples responded to the survey. The gay bar was the most common initial meeting place and relationships had lasted from less than one to 35 years. Few had had a commitment ceremony, although many reported wanting one if it were available. Most of the close friends of respondents were also gay couples and about two-thirds of family members were supportive of the relationship. The most persistent conflicts centered around finances and relations with family members. Virtually all respondents described their relationships as monogamous, but only about half practiced safe-sex. More attention needs to be given to understanding male couples and to targeting AIDS-prevention messages to them.     

Simulating Properties of the Likelihood Ratio Test for a Unit Root in an Explosive Second-Order Autoregression

This paper provides a means of accurately simulating explosive autoregressive processes and uses this method to analyze the distribution of the likelihood ratio test statistic for an explosive second-order autoregressive process of a unit root. While the standard Dickey-Fuller distribution is known to apply in this case, simulations of statistics in the explosive region are beset by the magnitude of the numbers involved, which cause numerical inaccuracies. This has previously constituted a bar on supporting asymptotic results by means of simulation, and analyzing the finite sample properties of tests in the explosive region.     

A bayesian test for a two-way contingency table using independence priors

One method of testing for independence in a two-way table is based on the Bayes factor, the ratio of the likelihoods under the independence hypothesis H and the alternative hypothesis H. The main difficulty in this approach is the specification of prior distributions on the composite hypotheses H and H. A new Bayesian test statistic is constructed by using a prior distribution on H that is concentrated about the “independence surface” H. Approximations are proposed which simplify the computation of the test statistic. The values of the Bayes factor are compared with values of statistics proposed by Gunel and Dickey (1974), Good and Crook (1987), and Spiegelhalter and Smith (1982) for a number of two-way tables. This investigation suggests a strong relationship between the new statistic and the p-value.     

Entropy Principles in Decision Making Under Risk

This paper considers decision problems where: (1) The exact probability distribution over the states of nature is not precisely known, but certain prior information is available about the possibilities of these outcomes; (2) A prior distribution over the states of nature is known, but new constraint information about the probabilities becomes available. The maximum entropy principle asserts that the probability distribution with maximum entropy, satisfying the prior knowledge, should be used in the decision problem. The minimum cross-entropy principle says that the posterior distribution is the one which minimizes cross-entropy, subject to the new constraint information. The entropy principles have not gone uncriticized, and this literature, together with that justifying the principles, is surveyed. Both principles are illustrated in a number of situations where the distribution is either discrete or continuous. The discrete distribution case with prior interval estimates based on expert opinions is considered in detail.