Illinois River 2006, Water Quality Assessment at the Arkansas Highway 59 Bridge

Automatic water sampler and a U. S. Geological Survey gauging station were established in 1995 on the main stem of the Illinois River at the Arkansas Highway 59 Bridge. Since that time, continuous stage and discharge measurements and water quality sampling have been used to determine pollutant concentrations and loads in the Arkansas portion of the Illinois River. This report represents the results from the measurement and sampling by the Arkansas Water Resources Center -Water Quality Lab for January 1, 2006 to December 31, 2006

2004 Pollutant Loads Kings River Near Berryville, Arkansas

An automatic sampler and a USGS gauging station were established in 1998 and water quality sampling was begun in 1999 on the Kings River near Berryville, Arkansas. Continuous stage and discharge measurements and frequent water quality sampling have been used to determine pollutant concentrations and loads in the river. This report presents the results from the sampling and analysis for January 1, 2004 to December 31, 2004

Illinois River 2004 Pollutant Loads at Arkansas Highway 59 Bridge

Automatic water sampler and a U. S. Geological Survey gauging station were established in 1995 on the main stem of the Illinois River at the Arkansas Highway 59 Bridge. Since that time, continuous stage and discharge measurements and water quality sampling have been used to determine pollutant concentrations and loads in the Arkansas portion of the Illinois River. This report represents the results from the measurement and sampling by the Arkansas Water Resources Center -Water Quality Lab for January 1, 2004 to December 31, 2004

Water Quality Sampling, Analysis and Annual Load Determinations for TSS, Nitrogen and Phosphorus at the Washington County Road 195 Bridge on the West Fork of the White River, 2004 Annual Report

A water quality sampling station was installed at the Washington County road 195 bridge on the West Fork of the White River just above the confluence of the three main forks of the Upper White River in December 2001. The Quality Assurance Project Plan (QAPP) was approved by EPA Region six on March 2002 and sampling was begun at that time. This station is coordinated with a USGS gauging station at the same location. This station was instrumented to collect samples at sufficient intervals across the hydrograph to accurately estimate the flux of total suspended solids, nitrogen and phosphorus into the upper end of Beaver Lake from the West Fork of the White River. The West Fork is listed on Arkansas\u27 1998 303d list as impaired from sediment. The Upper White was designated as the states highest priority watershed in the 1999 Unified Watershed Assessment. Accurate determination of stream nutrients and sediment is critical for future determinations of TMDLs, effectiveness of best management practices and trends in water quality

Water Quality Sampling, Analysis and Annual Load Determinations for TSS, Nitrogen and Phosphorus at the Washington County Road 76 Bridge on Ballard Creek

The Illinois River Basin has experienced water quality impairment from non-point source pollution for many years. This fact was well documented in the State of Arkansas\u27 Water Quality Assessment report, the Soil Conservation Service River Basin Study, and several University of Arkansas studies. Thirty-seven sub-watersheds have been identified by the SCS in the Arkansas portion of the Illinois River basin. In the Arkansas portion of the Basin, the Illinois River, Evansville Creek, Baron Fork, Cincinnati Creek, Muddy Fork, Moores Creek, Clear Creek, Osage Creek and Flint Creek were all classified as not supporting their designated use as primary contact recreation streams. The identified causes of the impairment were: sediment, bacteria and nutrients. In 1997, the University of Arkansas completed a project that estimated the phosphorus loading from each of the thirty-seven sub-watersheds. This project also prioritized watersheds for implementation work based on phosphorus loads, nitrogen loads and total suspended solids loads per unit area. The thirty-seven sub-watersheds were grouped into Low (16), Medium (10) and High (11) categories based on phosphorus loadings. If all the sub-watersheds above the median value for on phosphorus loading in the Illinois River basin were brought down to the current median value for phosphorus loading, this reduction would result in the agreed to 40% reduction of phosphorus at the state line. The selection of a sub-watershed for targeted intensive voluntary BMP implementation was based on the following criteria: a) the sub-watershed had to be above the current median value for phosphorus loading, b) there would be no sewage treatment plant in the sub-watershed, and c) land user interest. The Upper Ballard Creek watershed met all these requirements. The watershed covers 6700 hectares. The creek is listed in the High category with a unit area loading of 1.75 kg. per hectare per year. The median value for the thirty-seven watersheds is 0.73 kg. per hectare per year

Confirming the existence of π-allyl-palladium intermediates during the reaction of meta photocycloadducts with palladium(ii) compounds

The transient existence of π-allyl-palladium intermediates formed by the reaction of Pd(OAc)2 and anisole-derived meta photocycloadducts has been demonstrated using NMR techniques. The intermediates tended to be short-lived and underwent rapid reductive elimination of palladium metal to form allylic acetates, however this degradation process could be delayed by changing the reaction solvent from acetonitrile to chloroform

Statistical characterization of the GxxxG glycine repeats in the flagellar biosynthesis protein FliH and its Type III secretion homologue YscL

<p>Abstract</p> <p>Background</p> <p>FliH is a protein involved in the export of components of the bacterial flagellum and we herein describe the presence of glycine-rich repeats in FliH of the form AxxxG(xxxG)_<it>m</it>xxxA, where the value of <it>m </it>varies considerably in FliH proteins from different bacteria. While GxxxG and AxxxA patterns have previously been described, the long glycine repeat segments in FliH proteins have yet to be characterized. The Type III secretion system homologue to FliH (YscL, AscL, PscL, etc.) also contains a similar GxxxG repeat, and hence the presence of the repeat is evolutionarily conserved in these proteins, suggesting an important structural role or biological function.</p> <p>Results</p> <p>A set of FliH and YscL protein sequences was downloaded from GenBank, and then filtered to reduce redundancy, to ensure the soundness of the sequences, and to eliminate, as much as possible, confounding phylogenetic signal between individual sequences by implementing a pairwise 25% sequence identity cut-off. The general features of the glycine-rich repeats in these proteins were examined, and it was found that the length of these repeat segments varied substantially among FliH proteins but was fairly consistent for the Type III (YscL) homologue sequences, with values of <it>m </it>ranging from 0 to 12 for FliH and 0 to 2 for YscL. The amino acid sequence distribution of each of the three positions in the GxxxG repeats was found to differ significantly from the overall amino acid composition of the FliH/YscL proteins. The high frequency of Glu, Gln, Lys and Ala residues in the repeat positions, which is not likely indicative of any contaminating phylogenetic signal, suggests an α-helical structure for this motif. In addition, we sought to determine whether certain pairs of amino acids, in certain pairs of positions, were found together significantly more often than would be predicted by chance. Several statistically significant correlations were uncovered, which may be important for maintaining helical stability or for forming helix-helix interactions. These correlations are likely not of a phylogenetic origin as the originating sequences for the pair correlations are derived from a low similarity set and the individual incidences of the pair correlations do not cluster in any obvious phylogenetic sense, nor is there much evidence of strict sequence conservation outside the positions of the glycine residues. Finally, the α-helices from a non-redundant set of proteins from the Protein Data Bank were searched for GxxxG repeats similar in length to those found in FliH, however there were no helices containing more than three contiguous glycine repeat segments; thus, long glycine repeats similar to those found in FliH are presumably quite rare in nature.</p> <p>Conclusion</p> <p>The glycine repeats in YscL and particularly FliH represent an intriguing amino acid sequence motif that is very rare in nature. Although we do not attempt to offer a mechanism whereby these repeats may have evolved, we do place the existence of the motif and some residue pairings within a rational structural context. While crystal structures of these proteins are necessary to fully elucidate the structural and functional significance of these repeats, the characterization reported here represents a first step in understanding this unique sequence feature.</p