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ABSTRACT: Riparian buffer zones are effective in mitigating nonpoint source pollution and have been recommended as a best management practice (BMP). The Riparian Ecosystem Management Model (REMM) has been developed [...]

Dense dendritic stream networks in the Tifton Upland (southeastern U.S. coastal plain) provide an opportunity to determine the effects of land management practices on individual farms on downstream hydrology and water quality. A typical farm will be drained by two or three small streams. The streams may be bordered by riparian forests or impounded into farm ponds. Two adjacent farm-scale basins, both of which were 50 to 60 ha (124 to 148 ac) in size were compared for seven years to determine the effects of upstream agricultural land uses, downstream riparian zones, and small impoundments on stream water quality and hydrology. Stream water quality was sampled at four points on the two basins and at a downstream outlet where the two streams came together in a farm pond. The north basin had more cropland than the south basin and had much more area in plastic-covered beds for vegetable production. The south basin had less land in crop production and much more of the total basin area in farm ponds used to supply irrigation water. The north basin had more surface runoff and higher loads of all nutrients and sediment. The south basin had only 55% of the total runoff of the north basin, probably due to the presence of about 6% of the total watershed area in farm ponds. Up to 26% of the north basin (38% of total cropland) was occupied by wide plastic-covered beds in the last two years of the study. Large quantities of sediment transported in surface runoff from these fields on the north basin led to increases in sediment concentrations and loads of over 100 times compared to both the south basin and to earlier years of the study. Based on reductions in differences in loads and concentrations between upstream and downstream sites, there is less potential to reduce nutrients and sediment once these materials are in stream flow than when water is moving to streams through a riparian buffer. A downstream pond that received inputs from both the north and south basins had significantly lower concentrations of most nutrients and sediments than either of the upstream sampling sites. [ABSTRACT FROM AUTHOR]

BSTRACT: The approximate streamflow partitioning method which uses daily rainfall and streamfiow data was applied in Coastal Plain, Coastal Flatwoods, and Southern Piedmont physiographic regions for estimation of the surface and subsurface flow components of total streainflow. Sizes of the watersheds ranged from 9.6 km [ABSTRACT FROM AUTHOR]

Nitrogen (N) contamination of surface and groundwater is a health concern for both humans and animals. Excess nitrogen in surface water bodies may contribute to eutrophication. Elevated nitrate (NO3-N) concentrations in drinking water have caused infant death from the disease methemoglobinemia. Formation of potentially carcinogenic nitrosamines in the soil from nitrite (NO2-N) and secondary amines is also a health concern. Both NO3-N and NO2-N have been shown to negatively affect the metabolism of domestic animals. Movement of NO3-N and NO2-N to groundwater is of particular concern in the southeastern Coastal Plain because of the unique climatic, soil morphology, and geohydrologic regimes of the region. Climatically, the southeastern Coastal Plain is characterized by warm temperatures and relatively high rainfall. Because of the extended growing season, multicropping, which requires multiple applications of nitrogen, is commonly practiced. Annual rainfall distribution often also requires use of supplemental irrigation. The combination of relatively high nitrogen inputs, high rainfall, and use of irrigation for crop production coupled with areas of permeable sandy-textured soils and geologic materials means that large portions of the coastal plain may have high potential for nitrogen contamination of surface and ground waters. Research at the Southeast Watershed Research Laboratory (SEWRL), USDA-ARS, in cooperation with the University of Georgia over the past 20 years has focused on determining factors affecting nitrogen transport and transport rates over a range of coastal plain soils and management scenarios. This paper examines the findings from these extensive studies, reports new findings from a long term study, and synthesizes all information to examine the long-term implications for nitrogen contamination of soil and water from agriculture in the southeastern Coastal Plain. [ABSTRACT FROM AUTHOR]

Conservation programs developed and implemented by the USDA have led to land-use changes of large areas throughout the U.S. These changes in land-use may lead to changes in evapotranspiration and infiltration and subsequently to dramatic differences in hydrologic response. The impact of recent land-use changes was evaluated using observed precipitation and streamflow data from the Little River watershed in south-central Georgia in the U.S. Land-use patterns within the watershed were, examined through classification of satellite images collected from 1975 to 2003. While some changes in land-use were determined, analysis of the data indicated that the overall changes were less than the typical classification errors obtained. Based on the analysis of the satellite imagery, conservation practices implemented in the Little River watershed have not significantly altered total forest acreage. It addition, 34 years of hydrologic data collected from this watershed do not indicate any significant changes in hydrologic patterns. The long-term average ratio of annual flow to annual precipitation for the Little River watershed has remained stable at approximately 0.27. Year-to-year variation of the ratio varied from a high of 0.41 observed during a year with above-normal winter rainfall to 0.06 observed during a year with very low annual rainfall. When subwatersheds of the Little River were compared, significant differences in their responsiveness to rainfall were found. Linear regression between precipitation and streamflow produced regression coefficients between 0.62 and 0.90. These differences were attributed to differences in physical characteristics and land-use. Long-term data from the watersheds indicate that streamflow response is dominated by annual and seasonal precipitation characteristics. [ABSTRACT FROM AUTHOR]

The USDA Natural Resource Conservation Service curve number (CN) method for estimating surface runoff is frequently used in natural resource modeling. Water yield and subsequently water quality estimates depend heavily on CN selection. This study was conducted to estimate CNs for a cotton-peanut rotation under conventional and strip tillage (ST) methods for growing and dormant seasons. A comparison between alternative methods for calculating CN and their applicability was also made. Rainfall-runoff data measured from 1999 to 2005 at a field study site in South Georgia were used to calculate CNs by averaging, lognormal, and data-censoring methods. For conventional and STs, CNs by the averaging method using year-round data were 89 and 84, respectively, and by the lognormal method were 89 and 83, respectively. Results from the data-censoring method were 81 and 75, respectively, which matched standard table values developed from a long-term series of annual maximum runoff. Values were also found to vary by season. Curve numbers by the lognormal method for ST were 83 and 88 for growing and dormant seasons, respectively; however, there was no difference between growing and dormant seasons, 89, for conventional tillage. The corresponding CNs by the data-censoring method for ST were 71 and 79 for growing and dormant seasons, respectively, and for conventional tillage were 82 and 79 for growing and dormant seasons, respectively. Based upon errors of the estimates, runoff estimates showed no improvement when separate CNs for the two seasons were used. The data-censoring method CNs yielded lower runoff estimate errors than CNs obtained by the lognormal method. The data-censoring method is recommended for determining CNs from plot rainfall-runoff data pairs. [ABSTRACT FROM AUTHOR]

Many sampling projects have been initiated or modified in recent years to quantify the effects of water quality protection and enhancement programs. Although comprehensive references on the theory and procedures related to discharge data collection have been published, similar guides to water quality sampling are not available. Several sources provide general guidance on sampling project design and on manual sampling procedures, but only recently has detailed information on automated storm water quality sampling been developed. As a result, a compilation of available information on the design of water quality sampling projects is needed to support sound decision-making regarding data collection resources and procedural alternatives. Thus, the objective of this article is to compile and present practical guidance for collection of discharge and water quality constituent data at the field and small watershed scale. The guidelines included are meant to increase the likelihood of project success, specifically accurate characterization of water quality within project resource constraints. Although many considerations are involved in establishing a successful sampling project, the following recommendations are generally applicable to field and small watershed studies: (1) consider wet-weather access, travel time, equipment costs, and sample collection method in the selection of sampling site numbers and locations; (2) commit adequate resources for equipment maintenance and repair; (3) assemble a well-trained, on-call field staff able to make frequent site visits; (4) establish reliable stage-discharge relationships for accurate discharge measurement; (5) use periodic manual grab sample collection with adequate frequency to characterize baseflow water quality; (6) use flow-interval or time-interval storm sampling with adequate frequency to characterize storm water quality; and (7) use composite sampling to manage sample numbers without substantial increases in uncertainty. [ABSTRACT FROM AUTHOR]

Familial British dementia (FBD) is a rare neurodegenerative disorder and shares features with Alzheimer's disease, including amyloid plaque deposits, neurofibrillary tangles, neuronal loss, and progressive dementia. Immunohistochemical and biochemical analysis of plaques and vascular amyloid of FBD brains revealed that a 4 kDa peptide named ABri is the main component of the highly insoluble amyloid deposits. In FBD patients, the ABri peptide is produced as a result of a point mutation in the usual stop codon of the BRI gene. This mutation produces a BRI precursor protein 11 amino acids longer than the wild-type protein. Mutant and wild-type precursor proteins both undergo furin cleavage between residues 243 and 244, producing a peptide of 34 amino acids in the case of ABri and 23 amino acids in the case of the wild-type (WT) peptide. Here we demonstrate that the intramolecular disulfide bond in ABri and the C-terminal extension are required to elongate initially formed dimers to oligomers and fibrils. In contrast, the shorter WT peptide did not aggregate under the same conditions. Conformational analyses indicate that the disulfide bond and the C-terminal extension of ABri are required for the formation of beta-sheet structure. Soluble nonfibrillar ABri oligomers were observed prior to the appearance of mature fibrils. A molecular model of ABri containing three beta-strands, and two beta-hairpins annealed by a disulfide bond, has been constructed, and predicts a hydrophobic surface which is instrumental in promoting oligomerization.

Mycobacterium avium subspecies paratuberculosis (MAP) is a member of the M avium complex (MAC). It differs genetically from other MAC in having 14 to 18 copies of IS900 and a single cassette of DNA involved in the biosynthesis of surface carbohydrate. Unlike other MAC, MAP is a specific cause of chronic inflammation of the intestine in many animal species, including primates. The disease ranges from pluribacillary to paucimicrobial, with chronic granulomatous inflammation like leprosy in humans. MAP infection can persist for years without causing clinical disease. The herd prevalence of MAP infection in Western Europe and North America is reported in the range 21% to 54%. These subclinically infected animals shed MAP in their milk and onto pastures. MAP is more robust than tuberculosis, and the risk that is conveyed to human populations in retail milk and in domestic water supplies is high. MAP is harboured in the ileocolonic mucosa of a proportion of normal people and can be detected in a high proportion of full thickness samples of inflamed Crohn's disease gut by improved culture systems and IS900 polymerase chain reaction if the correct methods are used. MAP in Crohn's disease is present in a protease-resistant nonbacillary form, can evade immune recognition and probably causes an immune dysregulation. As with other MAC, MAP is resistant to most standard antituberculous drugs. Treatment of Crohn's disease with combinations of drugs more active against MAC such as rifabutin and clarithromycin can bring about a profound improvement and, in a few cases, apparent disease eradication. New drugs as well as effective MAP vaccines for animals and humans are needed. The problems caused by MAP constitute a public health issue of tragic proportions for which a range of remedial measures are urgently needed.

A solid phase approach has been used to synthesize a large branched disulphide peptide from IgG Fc, Ac-F-C*-A-K-V-N-N-K-D-L-P-A-P-I-E-K(Ac-E-L-L-G-G-P-S-V-F)-C*-I-NH2. This peptide combines the lower hinge region of IgG and a proximal beta-hairpin loop, both implicated in binding to Fc gammaRI. Solid phase Tl(tfa)3 cyclization of the linear branched peptide resulted in a poor yield of cyclic hinge-loop peptide (11%) most likely due to steric hindrance caused by the branch. However, if addition of the branch was preceded by solid phase Tl(tfa)3 cyclization of the loop, the yield was excellent at 75%. Cyclic hinge-loop peptide was active in displacing IgG2a from Fc gammaRI expressed on monocyte cell lines with an IC50 of 40 microM, whereas the linear form of this peptide was inactive. The Fc hinge-loop peptide demonstrates the potential for a non-mAb high affinity, immunomodulatory ligand for Fc gammaRI.

This retrospective study evaluated aging and rupture of silicone gel breast implants in 31 women. The implants were removed at a large multispecialty clinic from 1987 to 1990. The implants ranged in age from 1 to 17 years. Of the 51 implants removed, 27 were ruptured, 7 were leaking, and 17 were in good condition. Common reasons for implant removal were discomfort, firmness, or a mass adjacent to a ruptured implant. Injury to the breast (trauma or mammography) led to a removal in only 4 patients. Closed capsulotomies were common in both ruptured and intact groups. The number of intact implants declined over time. All implants older than 10 years were leaking or ruptured. There was a positive correlation between the duration of implantation time and the number of ruptured and leaking implants.

We have developed an in vitro technique for producing myocardial rupture in lamb hearts, which relates tensile strength to a variety of conditions which can prevail in normal and infarcted human hearts. Retrograde perfusion of saline solution and inflation of the left ventricle was used to apply progressive stress to the left ventricular wall. Three separate sites of myocardial rupture were observed and occurred with the frequency of 54% at the papillary muscle, 30% at the interventricular septum, and 16% at the free wall of the left ventricle. The distribution and configuration of the experimental ruptures were similar to those usually noted as complications of human myocardial infarction. The mean rupturing pressure was 526 mm Hg in normal lamb hearts. Application of these techniques should ultimately provide data relevant to the diagnosis, prevention, and treatment of myocardial rupture.