Live Well Springfield (LWS): Measuring Baseline Usage of the Springfield River Walk

OBJECTIVE: To measure RW usage prior to implementation of a targeted LWS intervention. METHODS: Users were automatically counted by TRAFx infrared trail counters, which were installed at three locations along the RW – Brightwood, Boathouse, and Depot. Data are expressed in counts, not in number of people, because the counters cannot determine user identity. Data represent counts from August through October 2013. RESULTS: The median daily counts for the Brightwood, Boathouse, and Depot locations were 70, 96, 181, respectively; mean counts were 69, 97, 189, respectively; and the range in counts were 39-133, 18-209, and 52-374, respectively. Hourly distributions varied. DISCUSSION: Brightwood had relatively high counts during the 6 PM hour (6:00 to 6:59), suggesting nearby residents using the trail after work. Boathouse counts showed no sharp hourly peaks, suggesting usage is less related to a typical work schedule. Depot counts peaked sharply during the 12 PM and 1 PM hours, suggesting employees from downtown using the trail on their lunch break. The range in counts at each location suggests that weather affected usage overall, while differences between locations suggest that characteristics of each location played a large role in determining counts. CONCLUSION: Results of this study will inform LWS programming and lay the foundation for post-intervention comparisons

Climate change, precipitation and impacts on an estuarine refuge from disease

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 6 (2011): e18849, doi:10.1371/journal.pone.0018849.Oysters play important roles in estuarine ecosystems but have suffered recently due to overfishing, pollution, and habitat loss. A tradeoff between growth rate and disease prevalence as a function of salinity makes the estuarine salinity transition of special concern for oyster survival and restoration. Estuarine salinity varies with discharge, so increases or decreases in precipitation with climate change may shift regions of low salinity and disease refuge away from optimal oyster bottom habitat, negatively impacting reproduction and survival. Temperature is an additional factor for oyster survival, and recent temperature increases have increased vulnerability to disease in higher salinity regions. We examined growth, reproduction, and survival of oysters in the New York Harbor-Hudson River region, focusing on a low-salinity refuge in the estuary. Observations were during two years when rainfall was above average and comparable to projected future increases in precipitation in the region and a past period of about 15 years with high precipitation. We found a clear tradeoff between oyster growth and vulnerability to disease. Oysters survived well when exposed to intermediate salinities during two summers (2008, 2010) with moderate discharge conditions. However, increased precipitation and discharge in 2009 reduced salinities in the region with suitable benthic habitat, greatly increasing oyster mortality. To evaluate the estuarine conditions over longer periods, we applied a numerical model of the Hudson to simulate salinities over the past century. Model results suggest that much of the region with suitable benthic habitat that historically had been a low salinity refuge region may be vulnerable to higher mortality under projected increases in precipitation and discharge. Predicted increases in precipitation in the northeastern United States due to climate change may lower salinities past important thresholds for oyster survival in estuarine regions with appropriate substrate, potentially disrupting metapopulation dynamics and impeding oyster restoration efforts, especially in the Hudson estuary where a large basin constitutes an excellent refuge from disease.Funding was provided by the Hudson River Foundation, grant number 00607A, and the New York State Department of Environmental Conservation (MOU 2008)

Coronary calcium scans and radiation exposure in the multi-ethnic study of atherosclerosis

With the increasing use of coronary artery calcium (CAC) scoring to risk stratify asymptomatic patients for future cardiovascular events, there have been concerns raised regarding the theoretical risk of radiation exposure to this potentially large patient population. Newer CT protocols have sought to reduce radiation exposure without compromising image quality, but the reported radiation exposures in the literature remains widely variable (0.7–10.5 mSv). In this study, we report the radiation exposure of calcium scoring from our MESA cohort across several modern CT scanners with the aim of clarifying the radiation exposure of this imaging modality. To evaluate the mean effective doses of radiation, using dose length product, utilized for coronary artery calcium scoring in the MESA cohort, in an effort to understand estimated population quantity effective dose using individual measurements of scanner radiation output using current CT scanners. We reviewed effective dose in milliSieverts (mSv) for 3442 participants from the MESA cohort undergoing coronary artery calcium scoring, divided over six sites with four different modern CT scanners (Siemens64, Siemens Somatom Definition, GE64, and Toshiba 320). For effective dose calculation (milliSieverts, mSv), we multiplied the dose length product by conversion factor k (0.014). The mean effective dose amongst all participants was 1.05 mSv, a median dose of 0.95 mSV. The mean effective dose ranged from 0.74 to 1.26 across the six centers involved with the MESA cohort. The Siemens Somatom Definition scanner had effective dose of 0.53 (n = 123), Siemens 64 with 0.97 (n = 1684), GE 64 with 1.16 (n = 1219), and Toshiba 320 with 1.26 mSv (n = 416). Subgroup analysis by BMI, age, and gender showed no variability between scanners, gender, ages 45–74 years old, or BMI less than 30 kg/m(2). Subjects over age 75 yo had a mean effective dose of 1.29 ± 0.31 mSv, while the <75 yo subgroup was 0.78 ± 0.09 mSv (p < 0.05). Effective doses in subjects with BMI > 40 kg/m(2) was significantly greater than other subgroups, with mean dose of 1.47 ± 0.51 mSv (p < 0.01). Using contemporary CT scanners and protocols, the effective dose for coronary artery calcium is approximately 1 mSv, an estimate which is consistently lower than previously reported for CAC scanning, regardless of age, gender, and body mass index