5,077 research outputs found
Tracking Bacterial Pollution Sources in Hampton Harbor
Fecal-borne microorganisms impact many shellfish-growing waters in coastal New Hampshire. Watersheds are often subject to fecal contamination by a variety of sources and efforts to improve water quality are often limited because of lack of information on which contaminant sources are most significant. Ribotyping and other microbial source tracking methods are useful new tools for providing information on the sources of fecal-borne bacterial contaminants in surface waters. New Hampshire has areas of abundant oyster (Crassostrea virginica) and clam (Mya arenaria) resources, the latter being most important in Hampton Harbor. In this study, Escherichia coli isolates (bacteria colonies) were obtained from water samples collected from ten sites in Hampton Harbor year-round during both dry and wet conditions. A library of known E. coli isolates was created from twenty different potential source species in the New Hampshire coastal watershed, including humans, livestock, pets, wildlife and avian species. The ribosomal RNA DNA of E. coli isolates was analyzed using ribotyping in which the patterns of ribosomal DNA were detected using chemiluminescence, then optimized and analyzed using GelCompar II software. A total of 249 isolates from the twenty known source species were used as a reference to identify sources for 390 unknown isolates from water samples taken from August 2000 through October 2001. Banding patterns for water samples and source species isolates were considered to be the same if there was 80% or greater similarity between patterns. Overall, sources for 62% of the isolates were identified
Evaluating the Stormwater Treatment Performance of AbTech Industries Smart Sponge® Plus, Landry, N
The ability of AbTech’s Smart Sponge® Plus to remove fecal-borne bacteria from stormwater was evaluated in a storm drainage system located in Seabrook, New Hampshire. The Smart Sponge ® Plus was installed into a water quality inlet and samples were collected from influent (pre-treatment) and effluent (post-treatment) for analysis of bacterial concentrations and loadings during 15 storm events from September 3, 2003 to May 24, 2004, excluding winter months. The 15 storms included events with a range of rainfall intensities and amounts, as well as accompanying runoff volumes. Flow weighted composite samples were analyzed for fecal coliforms, Escherichia coli and enterococci to determine if concentrations were lowered as stormwater passed through the Smart Sponge® Plus material. In most cases, bacterial concentrations were reduced within the treatment system, but to varying degrees. The efficiency ratio based on reduction in event mean concentration for each bacterial indicator in the flow was calculated for each storm event. The values ranged most widely for fecal coliforms, whereas the range of ratios was narrower and the values were more consistent for enterococci. The overall load reductions for the bacterial indicators were 50.3% for fecal coliforms, 51.3% for Escherichia coli and 43.2% for enterococci. Relatively consistent pH values were observed in influent and effluent samples. The overall range of pH values was large, ranging from 5.21 units in influent from storm event #11 to 7.64 units in influent from storm event #1. Conductivity values were gr eater in the effluent in 14 of the 15 storm events, especially in storm events #12 and #13 when effluent conductivities were \u3e50% higher than influent values. Quality assurance/quality control procedures supported the methods and results of the study. Overall, the observed reductions in bacterial concentrations in post-treatment stormwater would still result in discharge of elevated bacterial levels that would continue to limit uses in receiving waters
Family Well-Being: A Complex Challenge Worth Pursuing
Issue Editor, Susan Landry\u27s point of view and summary of the articles in Family Well-Being and Social Environments
Labyrinthic granular landscapes
We have numerically studied a model of granular landscape eroded by wind. We
show the appearance of labyrinthic patterns when the wind orientation turns by
. The occurence of such structures are discussed. Morever, we
introduce the density of ``defects'' as the dynamic parameter governing
the landscape evolution. A power law behavior of is found as a function
of time. In the case of wind variations, the exponent (drastically) shifts from
2 to 1. The presence of two asymptotic values of implies the
irreversibility of the labyrinthic formation process.Comment: 3 pages, 3 figure, RevTe
Impulse distributions in dense granular flows: signatures of large-scale spatial structures
In this paper we report the results of simulations of a 2D gravity driven,
dissipative granular flow through a hopper system. Measurements of impulse
distributions P(I) on the simulated system show flow-velocity-invariant
behavior of the distribution for impulses larger than the average impulse .
For small impulses, however, P(I) decreases significantly with flow velocity, a
phenomenon which can be attributed exclusively to collisions between grains
undergoing frequent collisions. Visualizations of the system also show that
these frequently colliding particles tend to form increasingly large linear
clusters as the flow velocity decreases. A model is proposed for the form of
P(I), given distributions of cluster size and velocity, which accurately
predicts the observed form of the distribution. Thus the impulse distribution
provides some insight into the formation and properties of these ``dynamic''
force chains.Comment: 4 pages, 4 figure
Effect of solid cattle manure injection on oat crop production in east-central Saskatchewan
Non-Peer Reviewe
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