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Residential land is expanding in the United States, and lawn now covers more area than the country's leading irrigated crop by area. Given that lawns are widespread across diverse climatic regions and there is rising concern about the environmental impacts associated with their management, there is a clear need to understand the geographic variation, drivers, and outcomes of common yard care practices. We hypothesized that 1) income, age, and the number of neighbors known by name will be positively associated with the odds of having irrigated, fertilized, or applied pesticides in the last year, 2) irrigation, fertilization, and pesticide application will vary quadratically with population density, with the highest odds in suburban areas, and 3) the odds of irrigating will vary by climate, but fertilization and pesticide application will not. We used multi-level models to systematically address nested spatial scales within and across six U.S. metropolitan areas-Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix, and Los Angeles. We found significant variation in yard care practices at the household (the relationship with income was positive), urban-exurban gradient (the relationship with population density was an inverted U), and regional scales (city-to-city variation). A multi-level modeling framework was useful for discerning these scale-dependent outcomes because this approach controls for autocorrelation at multiple spatial scales. Our findings may guide policies or programs seeking to mitigate the potentially deleterious outcomes associated with water use and chemical application, by identifying the subpopulations most likely to irrigate, fertilize, and/or apply pesticides., Competing Interests: The authors have declared that no competing interests exist.

In natural grasslands, C 4 plant dominance increases with growing season temperatures and reflects distinct differences in plant growth rates and water use efficiencies of C 3 vs. C 4 photosynthetic pathways. However, in lawns, management decisions influence interactions between planted turfgrass and weed species, leading to some uncertainty about the degree of human vs. climatic controls on lawn species distributions. We measured herbaceous plant carbon isotope ratios (δ 13 C, index of C 3 /C 4 relative abundance) and C 4 cover in residential lawns across seven U.S. cities to determine how climate, lawn plant management, or interactions between climate and plant management influenced C 4 lawn cover. We also calculated theoretical C 4 carbon gain predicted by a plant physiological model as an index of expected C 4 cover due to growing season climatic conditions in each city. Contrary to theoretical predictions, plant δ 13 C and C 4 cover in urban lawns were more strongly related to mean annual temperature than to growing season temperature. Wintertime temperatures influenced the distribution of C 4 lawn turf plants, contrary to natural ecosystems where growing season temperatures primarily drive C 4 distributions. C 4 cover in lawns was greatest in the three warmest cities, due to an interaction between climate and homeowner plant management (e.g., planting C 4 turf species) in these cities. The proportion of C 4 lawn species was similar to the proportion of C 4 species in the regional grass flora. However, the majority of C 4 species were nonnative turf grasses, and not of regional origin. While temperature was a strong control on lawn species composition across the United States, cities differed as to whether these patterns were driven by cultivated lawn grasses vs. weedy species. In some cities, biotic interactions with weedy plants appeared to dominate, while in other cities, C 4 plants were predominantly imported and cultivated. Elevated CO 2 and temperature in cities can influence C 3 /C 4 competitive outcomes; however, this study provides evidence that climate and plant management dynamics influence biogeography and ecology of C 3 /C 4 plants in lawns. Their differing water and nutrient use efficiency may have substantial impacts on carbon, water, energy, and nutrient budgets across cities., (© 2019 by the Ecological Society of America.)

Fifty-one cases of extrahepatic biliary atresia (EHBA) with associated anomalies were found in a study of EHBA (251 cases). Analysis of segregation patterns of these anomalies in individual patients suggested the existence of 2 major groups: (1) 15 cases (29.4%) with various combinations of anomalies within the laterality sequence, and (2) 30 cases (58.8%) with one or 2 anomalies mostly involving the cardiac, gastrointestinal, and urinary systems. These latter anomalies did not follow any recognizable pattern. The third group of 6 cases all had intestinal malrotation, some with preduodenal portal vein; these cases show some similarity to the laterality sequence group and may represent a more confined phenotypic result of faulty situs determination. This previously unattempted classification of patients with EHBA and associated anomalies might enable a more targeted approach towards identification of causes in this heterogeneous disorder. EHBA within the laterality sequence might prove a suitable candidate for a major gene mutation. Teratogenic, infectious and polygenic multifactorial causes might play a more significant role in EHBA associated with "nonsyndromic" organ system anomalies.

The Baltimore-Washington Infant Study is a regional epidemiologic study of congenital heart disease. Among Infants born in the study area in 1981 and 1982, 664 had a diagnosis of congenital heart disease confirmed in the first year of life by echocardiography, cardiac catheterization, cardiac surgery, or autopsy. The prevalence rate was 3.7/1,000 livebirths for all cases and 2.4/1,000 livebirths for cases confirmed by invasive methods only. Diagnosis-specific prevalence rates of congenital heart disease are compared with those of eight previous case series. Changing diagnostic categorizations in the time span covered and methodological differences resulted in great variation of the data. However, the data of the New England Infant Cardiac Program which used the same case discovery methods showed similar occurrences of major morphologic abnormalities, suggesting that these are stable basic estimates in the eastern United States. For all case series, the rate of confirmed congenital heart disease was approximately 4/1,000 livebirths over the 40-year time span.