Simple and accurate one‐sided inference from signed roots of likelihood ratios

The authors propose two methods based on the signed root of the likelihood ratio statistic for one‐sided testing of a simple null hypothesis about a scalar parameter in the présence of nuisance parameters. Both methods are third‐order accurate and utilise simulation to avoid the need for onerous analytical calculations characteristic of competing saddlepoint procedures. Moreover, the new methods do not require specification of ancillary statistics. The methods respect the conditioning associated with similar tests up to an error of third order, and conditioning on ancillary statistics to an error of second order.     

Re-evaluation of the Reference Dose for Methylmercury and Assessment of Current Exposure Levels

Methylmercury (Me-Hg) is widely distributed through freshwater and saltwater food chains and human consumption of fish and shellfish has lead to widespread exposure. Both the U.S. EPA Reference Dose (0.3 μg/kg/day) and the FAO/WHO Permissible Tolerable Weekly Intake (3.3 μg/kg/week) are currently based on the prevention of paraesthesia in adult and older children. However, Me-Hg exposure in utero is known to result in a range of developmental neurologic effects including clinical CNS symptoms and delayed onset of walking. Based on a critical review of developmental toxicity data from human and animal studies, it is concluded that current guidelines for the prevention of paraesthesia are not adequate to address developmental effects. A dose of 0.07 μ/kg/day is suggested as the best estimate of a potential reference dose for developmental effects. Data on nationwide fish consumption rates and Me-Hg levels in fish/seafood weighted by proportion of the catch intended for human consumption are analyzed in a Monte Carlo simulation to derive a probability distribution of background Me-Hg exposure. While various uncertainties in the toxicologic and exposure data limit the precision with which health risk can be estimated, this analysis suggests that at current levels of Me-Hg exposure, a significant fraction of women of childbearing age have exposures above this suggested reference dose.     

Microenvironmental Analysis of Residential Exposure to Chromium-Laden Wastes in and Around New Jersey Homes

The purpose of this study was to identify the significant microenvironments that can lead to chromium exposure in Hudson County, New Jersey residential settings near or on soil contaminated with chromium waste. Measurements were made in indoor air, outdoor air, and house dust. Surface dust was found to be the best index of potential Cr exposure. The values of Cr in Hudson County household dust ranged from 3.25-320 ng/cm2 in wipe samples and 1.0-12 ng/cm2 in vacuum samples. Elevated Cr in household dust was found to be related to residential locations near large chromium waste sites, household cleaning habits, and house renovation activities. Outdoor Cr air levels were similar to those obtained in other urban areas at these seasons of the year, approximately 5-7 ng/m3. Comparisons with measurements of the Cr levels in urine found that the elevated Cr in dust was associated with elevated excretion of Cr. Site-specific Cr differences in household dust suggest different sources and routes of exposure. Within the total group of homes in the present study, Cr in household dust was the major influence on household exposure.     

A disaggregated model of world production and trade: An estimate of the impact of the Tokyo Round

We present in this paper a computational model of world production, trade, and employment that is disaggregated by country and sector and report on the application of the model to the changes in tariffs and quantifiable nontariff barriers negotiated in the Tokyo Round that was concluded in 1979. The model incorporates supply and demand functions and market-clearing conditions for 22 tradable industries, plus markets for 7 nontradable industries, in each of the 18 major industrialized countries and 16 major developing countries. The equations of the model are presented in the text and the explicit functional forms in an appendix. The implementation of the model is discussed briefly.Application of the model to the Tokyo Round suggested that there will be small but beneficial effects on trade, domestic prices, and economic welfare in practically all the major industrialized countries and in some of the major developing countries. Because many of the NTB codes negotiated in the Tokyo Round were stated in advisory terms, their impact cannot be evaluated unambiguously at present. Further, many existing NTBs of importance were exempted altogether from the negotiations. The Tokyò Round must be viewed accordingly as having dealt with a somewhat limited part of all interferences with trade.     

Some differences between neurotic delinquents and other neurotic children 1

The Adoption and Safe Families Act (ASFA) neglects the clinical implications of permanency planning decisions for foster care children. The resulting decisions can undermine children's attachment-based treatment progress. The intersection of policy and practice with foster care children raises issues of ruptured attachments, communications between therapists and the larger macrolevel systems, the role of the therapist in the permanency decision process, and the impact of permanency decisions on treatment. An improved policy would promote greater coordination between clinical and court processes and would expand the criterion for permanency planning decisions to include the clinical needs of families.