An estimator of variance is described for production values calculated by the size‐frequency (Hynes) method. The number of sampling dates is identified as having an important influence on the variance estimate. A geometric mean is proposed to estimate the average weight of individuals when lost between size classes. In an example calculation, Ephemerella dorothea (Ephemeroptera) from North Branch Creek, Minnesota, had an annual production value of 8.5 g·m−2 wet and an approximate 95% confidence interval of 7.0–10.0. Similar calculations for Baetis sp. (Ephemeroptera) from the same river yielded an annual production value of 4.7 g·m−2 wet with a confidence interval of 3.6–5.8. Significant differences in annual production thus exist between these mayflies.

We constructed a cosmid vector, pOCA18, designed for transferring plant genomic libraries from Agrobacterium tumefaciens to plants. Clones from a genomic library of Arabidopsis thaliana DNA in pOCA 18 were propagated stably in both Escherichia coli and A. tumefaciens. Clones from the pOCA18 A. thaliana library were used to construct transgenic Nicotiana tabacum plants; the DNA inserts were transferred intact in 10 out of 16 transgenic N. tabacum plants examined but were partially deleted in six others. Transgenic N. tabacum plants constructed with a mutant A. thaliana acetohydroxy acid synthase gene (from the pOCA18 library) that encodes an enzyme resistant to the herbicide chlorsulfuron were resistant to chlorsulfuron. A statistical analysis indicated that if the A. thaliana library contains 10(7) members and if 10(7) A. tumefaciens transconjugants containing the library were used to transform plant cells, then 2 x 10(4) transformed plant cells must be generated to have a 95% probability of constructing a transgenic plant carrying a specific DNA sequence from the A. thaliana library.

Most screening programs to identify individuals at risk for type 1 diabetes have targeted relatives of people living with the disease to improve yield and feasibility. However, ∼90% of those who develop type 1 diabetes do not have a family history. Recent successes in disease-modifying therapies to impact the course of early-stage disease have ignited the consideration of the need for and feasibility of population screening to identify those at increased risk. Existing population screening programs rely on genetic or autoantibody screening, and these have yielded significant information about disease progression and approaches for timing for screening in clinical practice. At the March 2021 Type 1 Diabetes TrialNet Steering Committee meeting, a session was held in which ongoing efforts for screening in the general population were discussed. This report reviews the background of these efforts and the details of those programs. Additionally, we present hurdles that need to be addressed for successful implementation of population screening and provide initial recommendations for individuals with positive screens so that standardized guidelines for monitoring and follow-up can be established.

OBJECTIVES. The purpose of the study was to provide descriptive data and incidence data on adolescent work-related injuries and to determine whether such injuries are underreported to the Minnesota Department of Labor and Industry. METHODS. The study consisted of a 1-year survey of 534 adolescent work-related injuries reported to the Department of Labor and Industry and a cross-sectional survey of 3312 public high school students from throughout Minnesota. The high school survey used an abbreviated questionnaire with a subset of items from the Department of Labor and Industry survey. RESULTS. Ninety-six percent of the injuries were strains and sprains, cuts and lacerations, burns, bruises and contusions, and fractures. There were 11 hospitalizations; 4 were for burns that occurred during work in restaurants. Eighty workers (15%) reported permanent impairment as a result of their injuries. It was estimated that there were 2268 reportable injuries to working adolescents in Minnesota during the study year. CONCLUSIONS. The most common serious injuries were injuries to the lower back and burns. The demographic characteristics of adolescents whose injuries were reported to the Department of Labor and Industry were similar to those of injured adolescent workers identified through the high school survey. The results suggest that there is substantial underreporting of adolescent work injuries.

Variance estimators for fish production rates are explicitly derived for two production models: the instantaneous growth rate and increment summation methods. Statistics for standing stock, mean interval standing stock, instantaneous growth rate, and production:mean standing stock [Formula: see text] ratio are presented. The use of a jackknife estimator is proposed for estimating the variance of instantaneous growth rate. Comparison of the results from both production models provides a method of cross-validating results. The use of these statistics is illustrated in example calculations with trout population data. Brook trout (Salvelinus fontinalis) annual production in 1969 was significantly higher than combined annual production of brook trout, brown trout (Salmo trutta), and rainbow trout (Salmo gairdneri) in 1977. Variance estimates are affected by population and mean weight estimates. Validity of the production estimates is based on the validity of model assumptions.