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Threefold Reduction (threefold + reduction)
Selected AbstractsPrescribed-fire effects on rill and interrill runoff and erosion in a mountainous sagebrush landscape ,EARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2009Frederick B. Pierson Abstract Changing fire regimes and prescribed-fire use in invasive species management on rangelands require improved understanding of fire effects on runoff and erosion from steeply sloping sagebrush-steppe. Small (0·5 m2) and large (32·5 m2) plot rainfall simulations (85 mm h,1, 1 h) and concentrated flow methodologies were employed immediately following burning and 1 and 2 years post-fire to investigate infiltration, runoff and erosion from interrill (rainsplash, sheetwash) and rill (concentrated flow) processes on unburned and burned areas of a steeply sloped sagebrush site on coarse-textured soils. Soil water repellency and vegetation were assessed to infer relationships in soil and vegetation factors that influence runoff and erosion. Runoff and erosion from rainfall simulations and concentrated flow experiments increased immediately following burning. Runoff returned to near pre-burn levels and sediment yield was greatly reduced with ground cover recovery to 40 per cent 1 year post-fire. Erosion remained above pre-burn levels on large rainfall simulation and concentrated flow plots until ground cover reached 60 per cent two growing seasons post-fire. The greatest impact of the fire was the threefold reduction of ground cover. Removal of vegetation and ground cover and the influence of pre-existing strong soil-water repellency increased the spatial continuity of overland flow, reduced runoff and sediment filtering effects of vegetation and ground cover, and facilitated increased velocity and transport capacity of overland flow. Small plot rainfall simulations suggest ground cover recovery to 40 per cent probably protected the site from low-return-interval storms, large plot rainfall and concentrated flow experiments indicate the site remained susceptible to elevated erosion rates during high-intensity or long duration events until ground cover levels reached 60 per cent. The data demonstrate that the persistence of fire effects on steeply-sloped, sandy sagebrush sites depends on the time period required for ground cover to recover to near 60 per cent and on the strength and persistence of ,background' or fire-induced soil water repellency. Published in 2009 by John Wiley & Sons, Ltd. [source] Matrix metalloproteinase inhibitor, CTS-1027, attenuates liver injury and fibrosis in the bile duct-ligated mouseHEPATOLOGY RESEARCH, Issue 8 2009Alisan Kahraman Aim:, Excessive matrix metalloproteinase (MMP) activity has been implicated in the pathogenesis of acute and chronic liver injury. CTS-1027 is an MMP inhibitor, which has previously been studied in humans as an anti-arthritic agent. Thus, our aim was to assess if CTS-1027 is hepato-protective and anti-fibrogenic during cholestatic liver injury. Methods:, C57/BL6 mice were subjected to bile duct ligation (BDL) for 14 days. Either CTS-1027 or vehicle was administered by gavage. Results:, BDL mice treated with CTS-1027 demonstrated a threefold reduction in hepatocyte apoptosis as assessed by the TUNEL assay or immunohistochemistry for caspase 3/7-positive cells as compared to vehicle-treated BDL animals (P < 0.01). A 70% reduction in bile infarcts, a histological indicator of liver injury, was also observed in CTS-1027-treated BDL animals. These differences could not be ascribed to differences in cholestasis as serum total bilirubin concentrations were nearly identical in the BDL groups of animals. Markers for stellate cell activation (,-smooth muscle actin) and hepatic fibrogenesis (collagen 1) were reduced in CTS-1027 versus vehicle-treated BDL animals (P < 0.05). Overall animal survival following 14 days of BDL was also improved in the group receiving the active drug (P < 0.05). Conclusion:, The BDL mouse, liver injury and hepatic fibrosis are attenuated by treatment with the MMP inhibitor CTS-1027. This drug warrants further evaluation as an anti-fibrogenic drug in hepatic injury. [source] Improved pulse sequences for pure exchange solid-state NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 2 2004Thomas Vosegaard Abstract Spin-exchange experiments are useful for improving the resolution and establishment of sequential assignments in solid-state NMR spectra of uniformly 15N-labeled proteins oriented macroscopically in phospholipid bilayers. To exploit this advantage fully, it is crucial that the diagonal peaks in the two-dimensional exchange spectra are suppressed. This may be accomplished using the recent pure-exchange (PUREX) experiments, which, however, suffer from up to a threefold reduction of the cross-peak intensity relative to experiments without diagonal-peak suppression. This loss in sensitivity may severely hamper the applicability for the study of membrane proteins. In this paper, we present a two-dimensional exchange experiment (iPUREX) which improves the PUREX sensitivity by 50%. The performance of iPUREX is demonstrated experimentally by proton-mediated 15N,15N spin-exchange experiments for a 15N-labeled N -acetyl- L -valyl- L -leucine dipeptide. The relevance of exchange experiments with diagonal-peak suppression for large, uniformly 15N-labeled membrane proteins in oriented phospholipid bilayers is demonstrated numerically for the G-protein coupled receptor rhodopsin. Copyright © 2004 John Wiley & Sons, Ltd. [source] The CBS subdomain of inosine 5,-monophosphate dehydrogenase regulates purine nucleotide turnoverMOLECULAR MICROBIOLOGY, Issue 2 2008Maxim Pimkin Summary Inosine 5,-monophosphate dehydrogenase (IMPDH) catalyses the rate-limiting step in guanine nucleotide biosynthesis. IMPDH has an evolutionary conserved CBS subdomain of unknown function. The subdomain can be deleted without impairing the in vitro IMPDH catalytic activity and is the site for mutations associated with human retinitis pigmentosa. A guanine-prototrophic Escherichia coli strain, MP101, was constructed with the subdomain sequence deleted from the chromosomal gene for IMPDH. The ATP content was substantially elevated in MP101 whereas the GTP content was slighty reduced. The activities of IMPDH, adenylosuccinate synthetase and GMP reductase were two to threefold lower in MP101 crude extracts compared with the BW25113 wild-type strain. Guanine induced a threefold reduction in the MP101 ATP pool and a fourfold increase in the GTP pool within 10 min of addition to growing cells; this response does not result from the reduced IMPDH activity or starvation for guanylates. In vivo kinetic analysis using 14-C tracers and 33-P pulse-chasing revealed mutation-associated changes in purine nucleotide fluxes and turnover rates. We conclude that the CBS subdomain of IMPDH may coordinate the activities of the enzymes of purine nucleotide metabolism and is essential for maintaining the normal ATP and GTP pool sizes in E. coli. [source] Beating lensing cosmic variance with galaxy tomographyMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2004Ue-Li Pen ABSTRACT We discuss the use of cross-correlations between galaxies with distance information and projected weak lensing dark matter maps to obtain a fully three-dimensional dark matter map and power spectrum. On large scales (l, 100) one expects the galaxies to be biased, but not stochastic. I show that this allows a simultaneous solution of the full three-dimensional evolving galaxy bias and the dark matter power spectrum simultaneously. Within the photometric redshift information of the Canada,France,Hawaii (CFH) lensing legacy survey, this allows a threefold reduction of statistical error, while a cross-correlation with the Canadian Large Adaptive Reflector (CLAR) or other deep spectroscopic surveys allows a tenfold improvement in dark matter power accuracy on linear scales. This makes lensing surveys more sensitive to the cosmic equation of state and the neutrino masses. [source] Reduced sexual maturation in male post-smolt 1+ Atlantic salmon (Salmo salar L.) by dietary tetradecylthioacetic acidAQUACULTURE RESEARCH, Issue 5 2009Henriette Alne Abstract In the present study, the possible effect of dietary treatment on early sexual maturation in post-smolt Atlantic salmon, without any negative effect regarding growth, was investigated. The experiment was performed using 4400 individually marked (Pit tag) 1+ salmon, fed either a control diet or a diet supplemented with 0.5% tetradecylthioacetic acid (TTA) in duplicates for 3, 6 or 12 weeks after sea transfer. Compared with the control, dietary supplementation of TTA resulted in a threefold reduction in incidence of sexual mature males (0.6% vs. 1.8%). A curve-linear relationship between relative reduction in maturation and weeks of feeding TTA was found, indicating that the effect is most marked as a result of the first weeks of feeding and then levelling off. No negative dietary impact on growth was observed. As the level of fat in the muscle was reduced by dietary TTA, it seems that post-smolt supplemented dietary TTA do not accumulate high enough energy stores to start the maturation process, whereas the energy-enhancing effect of TTA due to increased fatty acid oxidation capacity may maintain the growth potential. Compared with immature salmon, sexually maturing fish revealed increased spring growth before the onset of maturation. [source] | ||||||||||