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Interest‐free loans are a common feature of low‐income rural economies. In much of the economics literature, lending at zero and positive interest are viewed as being highly segmented in the community, with interest‐free loans an essential component of long‐term mutual consumption agreements between households. An alternative interpretation is that zero‐interest loans are a credit contract that, in lieu of interest, includes an option allowing the lender to tax the borrower at a future date. This option can take a variety of forms, including the provision of labor or draft animal services or possibly a future loan. In this paper, we develop and test a model of household contract choice between zero– and positive–interest rate loans that builds on this alternative perspective. It highlights the role of borrower and lender attributes and the economic environment in which they interact in determining contract choice. Enforcement considerations are secondary. We use a unique household‐level data set ...

Using data from the Chicago Longitudinal Study, an ongoing panel investigation of more than 1,500 children, this article identifies a comprehensive set of predictors of educational attainment, employment, income, and adult crime. Predictors are measured from participants’ birth through high school by means of surveys and administrative records. These sources include data on individual, family, and school experiences, as well as on demographic attributes. Results from hierarchical regression analyses indicate that multiple indicators are associated with outcomes from a single domain, but few indicators (parental involvement in the child’s school, the child’s academic achievement at age 14, and juvenile arrest) predict outcomes across all domains.

We demonstrated the use of statistical tolerance intervals as a method for deriving acceptable thresholds for benthic macroinvertebrate community metrics. Tolerance intervals are simply confidence intervals based on percentiles, and they allow selection of acceptable limits (referred to as tolerance limits) and a desired level of statistical confidence for a metric distribution (e.g., of a reference population). We used benthic macroinvertebrate community data from several long-term monitoring projects for streams on the US Department of Energy’s Oak Ridge Reservation in eastern Tennessee, USA, for the demonstration. We focused on 3 benthic macroinvertebrate community metrics: density, total taxonomic richness, and taxonomic richness of Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa. Tolerance intervals yielded less restrictive thresholds than those produced by simple percentiles because the former approach includes variation of the reference data, whereas percentiles are distribution-free....

This article reviews the results of a multisite cohort study on effects of terminating Supplemental Security Income benefits for drug addiction and alcoholism. Within 2 years of the program’s termination, 35–43 percent of participants requalified for disability benefits for another impairment. Regardless of requalification status, substance abuse treatment participation declined sharply and illegal drug use was prevalent. Although many of those who did not requalify lost income, medical benefits, and housing, these losses lessened over time and were not associated with increased psychological or medical problems or with declines in other aspects of participants’ lives.

This study examines the behavior of money, inflation, and output under fiat and commodity standards to better understand how changes in monetary policy affect economic activity. Using long-term historical data for 15 countries, the study finds that the growth rates of various monetary aggregates are more highly correlated with inflation and with each other under fiat standards than under commodity standards. Money growth, inflation, and output growth are also higher under fiat standards. In contrast, the study does not find that money growth is more highly correlated with output growth under one type of standard than under the other. This study was originally published in the Journal of Political Economy (December 1997, vol. 105, no. 6, pp. 1308_21). It is reprinted in the Federal Reserve Bank of Minneapolis Quarterly Review with the permission of the University of Chicago Press.

An unusually rich cave fauna of 41 species is reported from a 20-m stretch of a shallow groundwater stream in Western Australia. Epigean waters do not occur upstream of the cave and, downstream, cave waters emerge at the surface after flowing about 100 m through a system of limestone caverns and collapses. Most of the aquatic cavernicoles collected from the cave stream, therefore, appear to be confined to the subterranean realm. Potential food sources for the aquatic fauna of the cave were investigated. Inputs of dissolved organic matter, surface debris, cadavers, and guano into the cave stream were lacking or too small to provide sufficient energy for the abundant aquatic cavernicoles. Aquatic root mats were shown to be the only substantial source of food available. They belong to the native tree Eucalyptus gomphocephala and consist of fine, highly branched, feeder rootlets growing in mycorrhizal association with fungi. Most of the animals, both in terms of density and species number, also occur in the submerged root mats. At least some of the aquatic cavernicoles graze directly on the living rootlets, some feed on root mat detritus, and others are predatory. We propose that tree roots provide an important source of energy for subterranean fauna in shallow groundwaters both in Australia and elsewhere.

A hedonic analysis of principal-agent employment contracts is developed in which workers and employers exchange labor services and contractual payment patterns. Within this framework, tests of alternative hypotheses are formulated and applied to contract data from a unique household-level survey of economic activity in rural China in 1935. The results indicate that credit market constraints motivated workers' and employers' contract choices, that shirking by workers rather than by employers was the dominant incentive issue, that reputational concerns rather than threats of termination were the key worker-disciplining device, and, finally, that the contract's third party acted as an enforcement device rather than as a matchmaker. Subject to the availability of matched agent-principal data, this structural approach to modeling agency relationships can also be used in contemporary settings.

A manipulative experiment was conducted to evaluate a biochemical method for using periphyton in water quality assessment. Periphyton assemblages that developed in situ on ceramic tiles placed in a reference site in one stream were transferred into a reference site and a polluted site in each of three streams in eastern Tennessee. Samples of periphyton from each site were analyzed for chlorophyll a content, rate of photosynthesis (by 14 C uptake), and fatty acid composition, 3, 17, and 35 days after being transferred to the sites. Chlorophyll a and photosynthetic rates per unit of chlorophyll at polluted sites were generally lower than at corresponding reference sites. More than 50 different fatty acids were separated and identified in the periphyton phospholipids; 12 of the 50 accounted for more than 90% of the total fatty acids. Periphyton fatty-acid biomarkers revealed differences in the periphyton taxonomic composition between reference and polluted sites. Fatty acid profiles indicated a shi...

A food augmentation experiment demonstrated that growth and lipid accumulation by grazing snails (Elimia clavaeformis) and caddisflies (Neophylax etnieri) from a snail-dominated stream in eastern Tennessee were strongly food limited. Elimia (two size classes) and third-instar Neophylax from White Oak Creek were given one of four diets in laboratory streams: (1) low-biomass periphyton (from White Oak Creek), (2) high-biomass periphyton (from an unshaded, nutrient-enriched stream that lacked effective grazers), (3) low-biomass periphyton and leaves, and (4) high-biomass periphyton and leaves. Small Elimia grew 2× faster and large Elimia grew 5× faster on high-biomass periphyton than on their normal diet of low-biomass periphyton. Neophylax grew 7× faster on the high-biomass periphyton. The high-biomass periphyton also produced significantly higher ratios of lipid to ash-free dry mass for both grazers. Leaf additions did not increase growth or lipid accumulation, even for Elimia, a feeding generalist. Measur...