Dispersal provided resilience to range collapse in a marine mammal: insights from the past to inform conservation biology.

Population loss is often a harbinger of species extinction, but few opportunities exist to follow a species' demography and genetics through both time and space while this occurs. Previous research has shown that the northern fur seal (Callorhinus ursinus) was extirpated from most of its range over the past 200-800 years and that some of the extirpated populations had unique life history strategies. In this study, widespread availability of subfossils in the eastern Pacific allowed us to examine temporal changes in spatial genetic structure during massive population range contraction and partial recovery. We sequenced the mitochondrial control region from 40 ancient and 365 modern samples and analyzed them through extensive simulations within a serial Approximate Bayesian Computation framework. These analyses suggest that the species maintained a high abundance, probably in subarctic refugia, that dispersal rates are likely 85% per generation into new breeding colonies, and that population structure was not higher in the past. Despite substantial loss of breeding range, this species' high dispersal rates and refugia appear to have prevented a loss of genetic diversity. High dispersal rates also suggest that previous evidence for divergent life history strategies in ancient populations likely resulted from behavioral plasticity. Our results support the proposal that panmictic, or nearly panmictic, species with large ranges will be more resilient to future disturbance and environmental change. When appropriately verified, evidence of low population structure can be powerful information for conservation decision-making.

Convergence and divergence in the evolution of aquatic birds.

Aquatic birds exceed other terrestrial vertebrates in the diversity of their adaptations to aquatic niches. For many species this has created difficulty in understanding their evolutionary origin and, in particular, for the flamingos, hamerkop, shoebill and pelecaniforms. Here, new evidence from nuclear and mitochondrial DNA sequences and DNA-DNA hybridization data indicates extensive morphological convergence and divergence in aquatic birds. Among the unexpected findings is a grouping of flamingos and grebes, species which otherwise show no resemblance. These results suggest that the traditional characters used to unite certain aquatic groups, such as totipalmate feet, foot-propelled diving and long legs, evolved more than once and that organismal change in aquatic birds has proceeded at a faster pace than previously recognized.

Missouri Firearm-Related Injury Surveillance System.

CONTEXT: The Missouri Department of Health collects hospital inpatient and emergency room records statewide. With mortality data, they make up a population-based surveillance system of firearm-related injuries. Much information is not captured by these data, however. OBJECTIVE: During a three-year project we attempted to develop a timely, representative, and sensitive surveillance system of firearms-related injuries and their circumstances. DESIGN: The surveillance system consisted of Missouri's hospital and mortality records linked to police records of firearm incidents. SETTING: Lack of standardization of police department data precluded a statewide surveillance system; therefore, we concentrated on the two largest urban areas, St. Louis and Kansas City. PARTICIPANTS: Firearm-related injuries occurring during crimes in the surveillance area in 1994 were recorded. Wounds inflicted unintentionally or during suicide attempts were excluded. MAIN OUTCOME MEASURES: We evaluated the system according to its simplicity, flexibility, acceptability, sensitivity, predictive value positive, representativeness, and timeliness. RESULTS: The surveillance system was neither timely nor simple. Though estimated to represent 95% of the desired cases, information about the firearms and the circumstances was relatively scant. CONCLUSIONS: Police records as they now exist cannot be included in a statewide firearms surveillance system. The cost/benefit ratio does not justify even a regional surveillance system. Standardization of police records would be helpful, but some information will always be lacking unless the perpetrator is arrested.

Unsafe driving behaviors and hospitalization.

The medical costs associated with motor vehicle crashes are difficult to measure. Most attempts have used crash data and cost data that are only indirectly related to each other or have followed patients in a few hospitals or trauma centers. These studies produce localized estimates or rough national estimates of limited use to policy makers. The result has been a dependence on more readily available mortality data, such as the Fatal Accident Reporting System, to guide automotive safety efforts. The limitations of mortality data and the increasing sophistication of medical care data bases have resulted in a strong interest in obtaining crash-linked morbidity data. Hence, in 1993, the National Highway Traffic Safety Administration (NHTSA) awarded the Missouri Department of Health and six other applicants grants to link automotive crash records to statewide ambulance trip, outpatient care, hospitalization and mortality records. By identifying an individual across multiple data sets, states would be able to determine directly the relationship of driver behaviors and crash characteristics to hospitalization rates and other medical outcomes. Examination of hospital pay source information would expose the toll of automotive crashes on public tax dollars. Having recently completed the record linkage phase of this project, Missouri Department of Health staff are beginning to analyze the impact of automotive crashes on health care costs in Missouri. In this report, three unsafe driving behaviors, failure to use a safety device (seatbelts and motorcycle helmets), driving under the influence of alcohol, and speeding, are related to the risk of hospitalization or death, hospital costs, and expected pay source.

Cardiovascular disease in Missouri: mortality, hospital discharges and risk factors.

The authors discuss the magnitude of cardiovascular disease in terms of mortality and medical care, while showing that significant proportions of Missourians are at risk of developing cardiovascular disease.

Trends in the incidence of treated end-stage renal disease secondary to diabetic nephropathy: 1975-1984.

A study of the incidence of treated end-stage renal disease (ESRD) secondary to diabetic nephropathy (DN) in Missouri from 1975 to 1984 documented a relative risk of treated ESRD due to DN 3.7 times higher for blacks than whites. Between 1980 and 1984, the incidence rate for treated ESRD due to DN increased by 150% for white patients and 315% for black patients. Blacks over age 50 have incidence rates of treated ESRD due to DN 4.9 times their white counterparts. Black females have the highest rate of all race/sex groups with DN. The escalating high risk of older blacks for treated ESRD due to DN mandates the development of effective community based identification and referral efforts.

Calibration and error in placental molecular clocks: a conservative approach using the cetartiodactyl fossil record.

The nature of the molecular and fossil record and their limitations must be ascertained in order to gain the most precise and accurate evolutionary timescale using genetic information. Yet the majority of such timescales are based on point estimates using fossils or the molecular clock. Here we document from the primary literature minimum and maximum fossil age estimates of the divergence of whales from artiodactyls, a commonly used anchor point for calibrating both mitogenomic and nucleogenomic placental timescales. We applied these reestimates to the most recently established placental timescale based on mitochondrial rRNA and several nuclear loci, and present an attempt to account for both genetic and fossil uncertainty. Our results indicate that disregard for fossil calibration error may inflate the power of the molecular clock when testing the time of ordinal diversification in context with the K-T boundary. However, the early history of placentals, including their superordinal diversification, remained in the Cretaceous despite a conservative approach. Our conclusions need corroboration across other frequently used fossil anchor points, but also with more genetic partitions on the linear relationship between molecular substitutions and geologic time.

Calibration of avian molecular clocks.

Molecular clocks can be calibrated using fossils within the group under study (internal calibration) or outside of the group (external calibration). Both types of calibration have their advantages and disadvantages. An internal calibration may reduce extrapolation error but may not be from the best fossil record, raising the issue of nonindependence. An external calibration may be more independent but also may have a greater extrapolation error. Here, we used the advantages of both methods by applying a sequential calibration to avian molecular clocks. We estimated a basal divergence within birds, the split between fowl (Galliformes) and ducks (Anseriformes), to be 89.8 +/- 6.97 MYA using an external calibration and 12 rate-constant nuclear genes. In turn, this time estimate was used as an internal calibration for three species-rich avian molecular data sets: mtDNA, DNA-DNA hybridization, and transferrin immunological distances. The resulting time estimates indicate that many major clades of modern birds had their origins within the Cretaceous. This supports earlier studies that identified large gaps in the avian fossil record and suggests that modern birds may have coexisted with other avian lineages for an extended period during the Cretaceous. The new time estimates are concordant with a continental breakup model for the origin of ratites.

Smoking and excess sick leave in a department of health.

Average number of sick leave hours per month taken by smoking and nonsmoking employees of Missouri's Department of Health were examined. During a 20-month period 97 smokers took 5.3 hours per month sick leave, whereas 309 nonsmokers took 4.3 hours, a 23% difference. Excess sick leave was taken by smokers regardless of their sex, marital status, or age group. Smokers who were male, unmarried, or older took 22% to 38% more sick leave than their nonsmoking counterparts. It was estimated that for excess sick leave only, the smokers cost the department $11,931 per year. Using total cost figures developed by Weiss yielded an estimated excess cost of $510,802 per year.

The early history of modern birds inferred from DNA sequences of nuclear and mitochondrial ribosomal genes.

The traditional view of avian evolution places ratites and tinamous at the base of the phylogenetic tree of modern birds (Neornithes). In contrast, most recent molecular studies suggest that neognathous perching birds (Passeriformes) compose the oldest lineage of modern birds. Here, we report significant molecular support for the traditional view of neognath monophyly based on sequence analyses of nuclear and mitochondrial DNA (4.4 kb) from every modern avian order. Phylogenetic analyses further show that the ducks and gallinaceous birds are each other's closest relatives and together form the basal lineage of neognathous birds. To investigate why other molecular studies sampling fewer orders have reached different conclusions regarding neognath monophyly, we performed jackknife analyses on our mitochondrial data. Those analyses indicated taxon-sampling effects when basal galloanserine birds were included in combination with sparse taxon sampling. Our phylogenetic results suggest that the earliest neornithines were heavy-bodied, ground-dwelling, nonmarine birds. This inference, coupled with a fossil bias toward marine environments, provides a possible explanation for the large gap in the early fossil record of birds.

Phylogeny and biogeography of ratite birds inferred from DNA sequences of the mitochondrial ribosomal genes.

The origin of the flightless ratite birds of the southern continents has been debated for over a century. Whether dispersal or vicariance (continental breakup) best explains their origin depends largely on their phylogenetic relationships. No consensus has been reached on this issue despite many morphological and molecular studies. To address this question further we sequenced a 2.8-kb region of mitochondrial DNA containing the ribosomal genes in representative ratites and a tinamou. Phylogenetic analyses indicate that Struthio (Africa) is basal and Rhea (South America) clusters with living Australasian ratites. This phylogeny agrees with transferrin and DNA hybridization studies but not with sequence analyses of some protein-coding genes. These results also require reevaluation of the phylogenetic position of the extinct moas of New Zealand. We propose a new hypothesis for the origin of ratites that combines elements of dispersal and vicariance.

Patterns of cigarette and smokeless tobacco use among children and adolescents.

Although cigarette and smokeless tobacco use are recognized as major problems among school-age youth, few nationwide or statewide data exist on the prevalence and patterns of use. To determine the patterns of tobacco use among children and adolescents in Missouri, self-report information was obtained from a representative sample of 5,431 students in grades 5, 8, and 12. Both cigarette smoking and smokeless tobacco use were more common among males than females for each grade level except the 12th, where 30% of females and 28% of males had smoked during the previous week. Smoking prevalence was considerably lower among blacks than whites. Smokeless tobacco use was rare among both blacks and females. Smokeless tobacco use was more common than cigarette smoking in rural areas, where 17% of 8th-grade males and 31% of 12th-grade males had used smokeless tobacco during the previous week. The mean age at first use of cigarettes was slightly lower in the rural than the urban area, whereas the mean age of initial smokeless tobacco use was more than a year earlier in the rural area. Data regarding the perceived difficulty of quitting smoking and quit rates suggested that adolescent females have more difficulty quitting smoking than males. Male smokeless tobacco users appeared to be more addicted than male cigarette smokers. Smokeless tobacco brand preference indicated that users may switch to progressively stronger types of smokeless tobacco as they get older and a nicotine tolerance is developed. The current study emphasizes the urgent need for carefully targeted tobacco prevention and cessation efforts among school-age youth.

Underestimates of student substance use by school personnel: a cause for concern?

The present study was designed to compare school personnel's (i.e., principals, counselors, teachers) estimates of student substance use with student self-reported data. Comparisons were made in 78 schools between 5431 student self-reports of tobacco, alcohol, and drug use and 170 school personnel's estimates of student substance use. The results indicated that a significant number of school personnel were unable to estimate student substance use. Personnel who did provide estimates typically underestimated the degree of substance use, in comparison to student self-reported substance use. School personnel did not significantly overestimate use in comparison to student self-reported substance use for any substance in any grade or geographic area. It is suggested that school personnel may resist the adoption of prevention programs because of a perceived lack of need due to underestimation of the substance use problem.

Report of an illness outbreak at the Harry S Truman State Office Building.

An acute epidemic of headache, mucosal irritation, fatigue, odd taste, and dizziness involving several hundred state government employees occurred in June 1986 in an office building in Missouri that housed 2,500 employees. A survey of 305 ill and 131 well employees demonstrated that ill employees were more likely to have perceived unusual odors and inadequate air flow in their work areas. The building has eight floors, seven of which are divided in half by an atrium, and 17 separate air handling systems. A total of 87% of the ill employees were concentrated in only three of the "half floors." Extensive investigation revealed no toxic substances or other direct causes for the illnesses, but several factors were identified that may have reduced air quality in the affected areas. These included a low proportion of outside air, associated with crowding, blocked vents, smoking, and use of office chemicals. This pattern of illness suggests epidemic anxiety state triggered by poor air quality.