Entity

Time filter

Source Type

Pacific Grove, CA, United States

Lannoo M.J.,Indiana University School of Medicine - Terre Haute | Petersen C.,Naval Facilities Engineering Command Atlantic | Lovich R.E.,Naval Facilities Engineering Command Southwest | Nanjappa P.,Association of Fish and Wildlife Agencies | And 3 more authors.
PLoS ONE | Year: 2011

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been devastating amphibians globally. Two general scenarios have been proposed for the nature and spread of this pathogen: Bd is an epidemic, spreading as a wave and wiping out individuals, populations, and species in its path; and Bd is endemic, widespread throughout many geographic regions on every continent except Antarctica. To explore these hypotheses, we conducted a transcontinental transect of United States Department of Defense (DoD) installations along U.S. Highway 66 from California to central Illinois, and continuing eastward to the Atlantic Seaboard along U.S. Interstate 64 (in sum from Marine Corps Base Camp Pendleton in California to Naval Air Station Oceana in Virginia). We addressed the following questions: 1) Does Bd occur in amphibian populations on protected DoD environments? 2) Is there a temporal pattern to the presence of Bd? 3) Is there a spatial pattern to the presence of Bd? and 4) In these limited human-traffic areas, is Bd acting as an epidemic (i.e., with evidence of recent introduction and/or die-offs due to chytridiomycosis), or as an endemic (present without clinical signs of disease)? Bd was detected on 13 of the 15 bases sampled. Samples from 30 amphibian species were collected (10% of known United States' species); half (15) tested Bd positive. There was a strong temporal (seasonal) component; in total, 78.5% of all positive samples came in the first (spring/early-summer) sampling period. There was also a strong spatial component-the eleven temperate DoD installations had higher prevalences of Bd infection (20.8%) than the four arid (<60 mm annual precipitation) bases (8.5%). These data support the conclusion that Bd is now widespread, and promote the idea that Bd can today be considered endemic across much of North America, extending from coast-to-coast, with the exception of remote pockets of naïve populations. Source


Fraser M.,Naval Facilities Engineering Command Southwest | Elgamal A.,University of California at San Diego | He X.,AECOM Technology Corporation | Conte J.P.,University of California at San Diego
Journal of Computing in Civil Engineering | Year: 2010

A bridge monitoring TestBed is developed as a research environment for sensor networks and related decision-support technologies. A continuous monitoring system, capable of handling a large number of sensor data channels and three video signals, is deployed on a four-span, 90-m long, reinforced concrete highway bridge. Of interest is the integration of the image and sensor data acquisition into a single computer, thereby providing accurate time synchronization between the response and corresponding traffic loads. Currently, video and acceleration records corresponding to traffic induced vibration are being recorded. All systems operate online via a high-speed wireless Internet network, allowing real-time data transmission. Elements of the above health monitoring framework are presented herein. Integration of these elements into an automated functional system is emphasized. The recorded data are currently being employed for structural system identification via a model-free technique. Effort is also underway to correlate the moving traffic loads with the recorded accelerations. Finally, the TestBed is available as a resource for verification of new sensor technologies, data acquisition/transmission algorithms, data mining strategies, and for decision-support applications. © 2010 ASCE. Source


Capiro N.L.,Tufts University | Granbery E.K.,Georgia Institute of Technology | Lebron C.A.,Engineering Service Center | Major D.W.,Geosyntec Consultants | And 6 more authors.
Environmental Science and Technology | Year: 2011

A combination of batch and column experiments evaluated the mass transfer of two candidate partitioning electron donors (PEDs), n-hexanol (nHex) and n-butyl acetate (nBA), for enhanced bioremediation of trichloroethene (TCE)-dense nonaqueous phase liquid (DNAPL). Completely mixed batch reactor experiments yielded equilibrium TCE-DNAPL and water partition coefficients (KNW) for nHex and nBA of 21.7 ± 0.27 and 330.43 ± 6.7, respectively, over a range of initial PED concentrations up to the aqueous solubility limit of ca. 5000 mg/L. First-order liquid-liquid mass transfer rates determined in batch reactors with nBA or nHex concentrations near the aqueous solubility were 0.22 min-1 and 0.11 min-1, respectively. Liquid-liquid mass transfer under dynamic flow conditions was assessed in one-dimensional (1-D) abiotic columns packed with Federal Fine Ottawa sand containing a uniform distribution of residual TCE-DNAPL. Following pulse injection of PED solutions at pore-water velocities (vp) ranging from 1.2 to 6.0 m/day, effluent concentration measurements demonstrated that both nHex and nBA partitioned strongly into residual TCE-DNAPL with maximum effluent levels not exceeding 35% and 7%, respectively, of the applied concentrations of 4000 to 5000 mg/L. PEDs persisted at effluent concentrations above 5 mg/L for up to 16 and 80 pore volumes for nHex and nBA, respectively. Mathematical simulations yielded KNW values ranging from 44.7 to 48.2 and 247 to 291 and liquid-liquid mass transfer rates of 0.01 to 0.03 min-1 and 0.001 to 0.006 min-1for nHex and nBA, respectively. The observed TCE-DNAPL and water mass transfer behavior suggests that a single PED injection can persist in a treated source zone for prolonged time periods, thereby reducing the need for, or frequency of, repeated electron donor injections to support bacteria that derive reducing equivalents for TCE reductive dechlorination from PED fermentation. © 2011 American Chemical Society. Source


Salter-Blanc A.J.,Oregon Health And Science University | Suchomel E.J.,Geosyntec Consultants | Fortuna J.H.,Klohn Crippen Berger Ltd. | Nurmi J.T.,Clackamas Community College | And 6 more authors.
Ground Water Monitoring and Remediation | Year: 2012

The efficacy and feasibility of using zerovalent zinc (ZVZ) to treat 1,2,3-trichloropropane (TCP)-contaminated groundwater was assessed in laboratory and field experiments. In the first portion of the study, the reactivity of commercially available granular ZVZ toward TCP was measured in bench-scale batch-reactor and column experiments. These results were used to design columns for on-site pilot-scale treatment of contaminated groundwater at a site in Southern California. Two of the ZVZ materials tested were found to produce relatively high rates of TCP degradation as well as predictable behavior when scaling from bench-scale to field testing. In addition, there was little decrease in the rates of TCP degradation over the duration of field testing. Finally, no secondary impacts to water quality were identified. The results suggest that ZVZ may be an effective and feasible material for use in engineered treatment systems, perhaps including permeable reactive barriers. Ground Water Monitoring & Remediation. © 2012, National Ground Water Association. Source


Petersen C.E.,Naval Facilities Engineering Command Atlantic | Lovich R.E.,Naval Facilities Engineering Command Southwest | Phillips C.A.,University of Illinois at Urbana - Champaign | Dreslik M.J.,University of Illinois at Urbana - Champaign | Lannoo M.J.,Indiana University School of Medicine - Terre Haute
EcoHealth | Year: 2016

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian declines on almost all continents. We report on prevalence and intensity of Bd in the United States amphibian populations across three longitudinally separated north-to-south transects conducted at 15 Department of Defense installations during two sampling periods (late-spring/early summer and mid to late summer). Such a standardized approach minimizes the effects of sampling and analytical bias, as well as human disturbance (by sampling restricted military bases), and therefore permits a cleaner interpretation of environmental variables known to affect chytrid dynamics such as season, temperature, rainfall, latitude, and longitude. Our prevalence of positive samples was 20.4% (137/670), and our mean intensity was 3.21 zoospore equivalents (SE = 1.03; range 0.001–103.59). Of the 28 amphibian species sampled, 15 tested positive. Three sites had no evidence of Bd infection; across the remaining 12 Bd-positive sites, neither infection prevalence nor intensity varied systematically. We found a more complicated pattern of Bd prevalence than anticipated. Early season samples showed no trend associated with increasing temperature and precipitation and decreasing (more southerly) latitudes; while in late season samples, the proportion of infected individuals decreased with increasing temperature and precipitation and decreasing latitudes. A similar pattern held for the east–west gradient, with the highest prevalence associated with more easterly/recently warmer sites in the early season then shifting to more westerly/recently cooler sites in the later season. Bd intensity across bases and sampling periods was comparatively low. Some of the trends in our data have been seen in previous studies, and our results offer further continental-level Bd sampling over which more concentrated local sampling efforts can be overlaid. © 2016 International Association for Ecology and Health (outside the USA) Source

Discover hidden collaborations