Water Quality Monitoring of the Little Calumet East Branch Watershed

The Little Calumet East Branch (LCEB) is a 10-digit hydrologic unit code (HUC) watershed that ultimately discharges into Lake Michigan. The watershed begins in unincorporated LaPorte County and discharges west through unincorporated Porter County, converges with the West Branch of the Little Calumet River, and finally discharges into Lake Michigan via the Burns Ditch Waterway. A water quality monitoring study was performed in the summer of 2012 as part of the watershed management process led by a not-for-profit organization, Save the Dunes. Save the Dunes’ Great Lakes Innovative Stewardship through Education Network (GLISTEN) liaisons initiated weekly monitoring at eleven LCEB sites for nine weeks during the summer 2012 recreational period. The Indiana Department of Environmental Management (IDEM) conducted monthly monitoring of 48 sites in the LCEB including the sites monitored by the GLISTEN liaisons. Parameters measured for in the watershed included nitrogen, pH, phosphorus, dissolved oxygen, conductivity, water flow, and Escherichia coli

The Collective Dynamics of Smoking in a Large Social Network

Based on repeated surveys of 12,067 closely interconnected people between 1971 and 2000, examines the extent to which smoking spreads socially and to which groups of smokers quit together, as well as trends in the number and social centrality of smokers

COMPENSATING VARIATION FOR RECREATIONAL POLICY: A RANDOM UTILITY APPROACH TO BOATING IN FLORIDA

A nested logit random utility travel cost model is developed for recreational boating in southwest Florida. Using data from a survey of recreational boaters, the model estimates site choice probabilities and compensating variation for changes in boating speed limits. Behavior is modeled as a two-step, discrete-choice process, where boaters first select a launch point for their trailered boats, then select a boating destination based on site characteristics. The results of this particular model are currently being used in policy applications in Florida.Resource /Energy Economics and Policy,

The Correlation Between Metallicity and Debris Disk mass

We find that the initial dust masses in planetary debris disks are correlated with the metallicities of their central stars. We compiled a large sample of systems, including Spitzer, the Herschel DUNES and DEBRIS surveys, and WISE debris disk candidates. We also merged 33 metallicity catalogs to provide homogeneous [Fe/H] and $\sigma_{[Fe/H]}$ values. We analyzed this merged sample, including 222 detected disks (74 warm and 148 cold) around a total of 187 systems (some with multiple components) and 440 disks with only upper limits (125 warm and 315 cold), around a total of 360 systems. The disk dust masses at a common early evolutionary point in time were determined using our numerical disk evolutionary code, evolving a unique model for each of the 662 disks backward to an age of 1 Myr. We find that disk-bearing stars seldom have metallicities less than [Fe/H] = -0.2 and that the distribution of warm component masses lacks examples with large mass around stars of low metallicity ([Fe/H] < -0.085). Previous efforts to find a correlation have been largely unsuccessful; the primary improvements supporting our result are: 1.) basing the study on dust masses, not just infrared excess detections; 2.) including upper limits on dust mass in a quantitative way; 3.) accounting for the evolution of debris disk excesses as systems age; 4.) accounting fully for the range of uncertainties in metallicity measurements; and 5.) having a statistically large enough sample.Comment: 13 pages, 7 figures, accepted for publication to Ap