LBI tests for the detection of compound normal distribution in control and treatment populations

Independent samples are drawn from control and treatment populations with normal and compound normal distributions respectively. We derive the locally best invariant (LBI) tests through Wijsman’s representation for the detection of mixture departures from the normal distribution. These tests may be viewed as tests for the equality of control and treatment populations. Further, they are optimally robust for the model considered by Durairajan and Raman (1994).     

Dropouts and continuers in Gamblers Anonymous: Life-context and other factors

The design, aims and rationale are outlined of a follow-up study of dropouts from Gamblers Anonymous. A cohort of those attending for the first time and dropping out after more than one meeting was contacted and the cooperators given a structured interview examining factors which may have contributed to decisions to dropout. A comparison group of continuers from the same meeting who had been totally abstinent for at least a year were given the same structured interviews. This first of four parts examines life context factors making it more difficult to maintain attendance, commitment to the treatment program, perceived pre-meeting expectations and reasons for coming, impacts of the first meeting, effects of pressures to maintain attendance and the influence of spouses.     

Scenarios for the Indian iron and steel industry

Iron and steel is a key industry in the Indian economy. The author looks at the prospects into the next century and the options facing the industry over the next two decades. New capacity will have to be undertaken but it will undoubtedly be difficult to fund this without external assistance and without diverting resources from other areas. Thus it will be necessary to plan for technological innovation to achieve production objectives, and such technology must be developed in India, or imported and adapted to suit indigenous conditions.     

A note on revelation of information for joint production

If investors' attitudes toward risk are sufficiently similar to admit an efficient sharing rule that is linear, then this rule also provides sufficient incentives for truthful revelation of private information relevant for joint production decisions.Research support from the Office of Naval Research contract ONR-N00014-79-C-0685 and the National Science Foundation grants SOC-75-21820 and SES-81-08226 is gratefully acknowledged. This paper was prepared during the term of a Guggenheim Fellowship     

Analyzing migration decisions: the first step-whose decisions?

Many theories of geographic mobility assume that the change-of-residence process includes a substantial degree of choice. This paper classifies stated reasons for moving from the 1973 through 1977 Annual Housing Survey into forced, imposed, and preference-dominated categories. About 25 percent of residential mobility and 40 percent of migration occurred under conditions of substantial constraint. Mobility was most often constrained by family dynamics; for migration, occupational relocations frequently imposed the decision-to-move process and determined destinations. The volume of constrained movement indicates that its impact upon individuals, population dynamics, and voluntaristic theories of mobility deserves greater consideration.     

Determinants of fertility levels and change among developed countries: 1958–1978

This article provides a multivariate cross-national test of the hypothesis that national population/family planning policies have effected levels, and changes in fertility in developed nations over the past two decades. Variation is assessed in the total fertility rates (TFR) in 1978, and in the change in these rates between 1958 and 1978, among thirty developed countries. Measures include socioeconomic development, divorce, percent in consensual unions, female labor force participation, abortion policy, and level of contraceptive use by married couples and, government population/family planning policy. Seventy percent of the variation in 1978 TFR is related to the percent contracepting, female labor force, and the population/family planning policy measures. These are the only measures with significant direct effects. A longitudinal analysis of 1958 to 1978 change in TFRs is also conducted. This model increases R² to 75%, and the three independent variables remain significant. Implications of these findings for policy makers interested in increasing or decreasing fertility rates are noted.     

Species richness and altitudinal variation in the aquatic metazoan community in bamboo phytotelmata from north Sulawesi

We compared the aquatic metazoan community structure in bamboo stumps between a lowland (Kosinggolan; 200 m a.s.l.) and a highland site (Moat; 1030–1050 m a.s.l.) in North Sulawesi. The lowland bamboo stumps harbored 38 taxa including 2 predators, and the highland stumps harbored 35 taxa including 2 predators. In total 45 taxa were recorded, including 3 predators. Dominant detritivores were Tipulidae, Scirtidae, Chironomidae, Culicidae and Ceratopogonidae. The sole dominant predators wereToxorhynchites mosquito larvae, which occurred in 67% and 28% of stumps at the lowland and the highland sites, respectively. Although the mean biomass per stump did not differ significantly between the sites, the mean number of species per stump was significantly smaller at the lowland site. In addition, the variation in species composition among stumps was greater at the lowland site than at the highland site. Among dominant taxonomic groups, the number of non-predatory culicid species per stump was smaller at the lowland site where their predator,Toxorhynchites, was more abundant, although both sites had the same number of culicid species. In the presence ofToxorhynchites, the density and biomass of other culicids per stump were reduced significantly. The difference in predator density might affect differences in the local-scale community structure of individual bamboo stumps.