182 research outputs found
Predation by Pellet-Reared Tiger Muskellunge on Minnows and Bluegills in Experimental Systems
Studies in Wisconsin lakes have shown that stocked tiger muskellunge( F1 hybrids of female muskellunge, Esox masquinongy * male northern pike, E.lucius) reared on live food survive better than those reared entirely on dry pellet food. We evaluated the ability of pellet-reared hybrids to convert to a minnow(Notropis spp. and Pimephales promelas) or bluegill (Lepomis macrochirus) diet in laboratory aquaria and hatchery ponds. In aquaria, 86-310-mm (total length) tiger
muskellunge selected cyprinids that were about 40% of their own length and bluegills that were about 30% of their length, sizes closely predicted by an optimal foraging construct (time from prey capture to complete prey ingestion / prey dry weight). Using these prey sizes, we tested hybrids (130, 150, and 170mm long) in conversion experiments in aquaria and ponds. During experiments, prey were maintained at a constant density and predators were sampled periodically to determine the proportion eating fish. Tiger muskellunge converted more slowly to bluegills than to minnows in both aquaria and ponds. In aquaria, 85% of the hybrids converted from pellets to minnows by day 3, whereas only 68% converted to bluegills. By day 5, conversions to minnows and bluegills were 95% and 82%, respectively. In ponds, 73% of the hybrids
converted to minnows by day 5 and 89% by day 14. No hybrids had eaten bluegills by day 3
and only 53% converted by day 14. The apparently limited ability of pellet-reared tiger muskellunge to switch to a bluegill diet may influence survival and growth of these predators in reservoirs dominated by a centrachid forage base.This research was supported in part by funds from the Federal Aid in Fish Restoration Act under Dingell-Johnson Project F-57-R
Review of nuclear power plant safety cable aging studies with recommendations for improved approaches and for future work.
Many U. S. nuclear power plants are approaching 40 years of age and there is a desire to extend their life for up to 100 total years. Safety-related cables were originally qualified for nuclear power plant applications based on IEEE Standards that were published in 1974. The qualifications involved procedures to simulate 40 years of life under ambient power plant aging conditions followed by simulated loss of coolant accident (LOCA). Over the past 35 years or so, substantial efforts were devoted to determining whether the aging assumptions allowed by the original IEEE Standards could be improved upon. These studies led to better accelerated aging methods so that more confident 40-year lifetime predictions became available. Since there is now a desire to potentially extend the life of nuclear power plants way beyond the original 40 year life, there is an interest in reviewing and critiquing the current state-of-the-art in simulating cable aging. These are two of the goals of this report where the discussion is concentrated on the progress made over the past 15 years or so and highlights the most thorough and careful published studies. An additional goal of the report is to suggest work that might prove helpful in answering some of the questions and dealing with some of the issues that still remain with respect to simulating the aging and predicting the lifetimes of safety-related cable materials
Fluorosilicone and silicone o-ring aging study.
Fluorosilicone o-ring aging studies were performed. These studies examined the compressive force loss of fluorosilicone o-rings at accelerated (elevated) temperatures and were then used to make predictions about force loss at room temperature. The results were non-Arrhenius with evidence for a lowering in Arrhenius activation energies as the aging temperature was reduced. The compression set of these fluorosilicone o-rings was found to have a reasonably linear correlation with the force loss. The aging predictions based on using the observed curvature of the Arrhenius aging plots were validated by field aged o-rings that yielded degradation values reasonably close to the predictions. Compression set studies of silicone o-rings from a previous study resulted in good correlation to the force loss predictions for the fluorosilicone o-rings from this study. This resulted in a preliminary conclusion that an approximately linear correlation exists between compression set and force decay values for typical fluorosilicone and silicone materials, and that the two materials age at similar rates at low temperatures. Interestingly, because of the observed curvature of the Arrhenius plots available from longer-term, lower temperature accelerated exposures, both materials had faster force decay curves (and correspondingly faster buildup of compression set) at room temperature than anticipated from typical high-temperature exposures. A brief study on heavily filled conducting silicone o-rings resulted in data that deviated from the linear relationship, implying that a degree of caution must be exercised about any general statement relating force decay and compression set
Soybean seed protein, oil, fatty acids, and mineral composition as influenced by soybean-corn rotation
Effects of crop rotation on soybean (Glycine max (L) Merr.) seed composition have not been well investigated. Therefore, the objective of this study was to investigate the effects of soybean-corn (Zea mays L.) rotations on seed protein, oil, and fatty acids composition on soybean. Soybeans were grown at Stoneville, MS, from 2005 to 2008 in five different scheduled cropping sequences. In 2007, following three years of rotation with corn, seed oleic acid percentage was significantly higher in any crop rotation than continuous soybean. The increase of oleic fatty acid ranged from 61 to 68% in 2007, and from 27 to 51% in 2008, depending on the rotation. The increase of oleic acid was accompanied by significant increases in seed concentrations of phosphorus (P), iron (Fe), and boron (B). In 2007, the increase of P ranged from 60 to 75%, Fe from 70 to 72%, and B from 34 to 69%. In 2008, the increase of P ranged from 82 to 106%, Fe from 32 to 84%, and B from 62 to 77%. Continuous soybean had higher linoleic:oleic ratio and linoleic: palmitic + stearic + oleic ratio, indicating that relative quantity of linoleic acid decreased in rotated crops. The total production of protein, oil, stearic and oleic fatty acids was the lowest in continuous soybean. The total production of palmitic acid was inconsistent across years. The results show that soybean- corn rotation affects seed composition by consistently increasing seed oleic fatty acid, P, Fe, and B concentrations. Higher oleic acid, unsaturated fatty acid, is desirable for oil stability and long-shelf storage. The mechanisms of how these nutrients are involved are not yet understood
Ecology and management of western ragweed on rangeland
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Range improvement studies - 1984
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Soybean Seed Protein, Oil, and Fatty Acids are Altered by S and S + N Fertilizers Under Irrigated or Non-irrigated Environments
Information on the effect of sulfur (S) or sulfur+nitrogen (S + N) on soybean seed composition is scarce. Thus, the objective of this study was to investigate the effects of S, and S + N fertilizers on soybean [(Glycine max (L.) Merr.)] seed composition in the Early Soybean Production System (ESPS) under irrigated (I) and nonirrigated (NI) environments. Two separate field experiments were conducted from 2005 to 2007. One experiment was irrigated, and the second experiment was nonirrigated. Under I condition, S at a rate of 44.8 kg/ha alone or with N at 112 kg/ha resulted in a consistent increase in seed protein and oleic acid concentrations, and a decrease in oil and linolenic acid concentrations compared with the control (C). For example, in 2006 and compared with the C, application of S + N increased the percentage up to 11.4% and 48.5% for protein and oleic acid, respectively. However, oil concentration decreased by 3%. Protein and oleic acid increase were accompanied by a higher percentage of leaf and seed N and S. Under NI conditions, seed protein and oleic acid concentrations were significantly higher in C than in any S or S + N treatments, but the oil and linolenic acid concentrations were significantly lower. The results indicate that specific rate of S alone or S + N combined can alter seed composition under irrigated or nonirrigated conditions. This knowledge may help plant breeders to develop and release cultivars to suit specific target locations to grow new value-added soybeans or select for specific seed composition traits under specific environmental stress factors such as drought
A fragmentary leptonectid ichthyosaurian from the lower Pliensbachian of Luxembourg
peer reviewedDespite abundant fossils, the quality of the fossil record of Early Jurassic marine reptiles strongly fluctuates with time and space. Pliensbachian strata have yielded very few marine reptile remains, especially outside of England, obscuring the evolution of marine reptiles during the middle part of the Early Jurassic. We report a new Pliensbachian locality from Luxembourg that contains abundant marine fauna and ichthyosaurian remains likely representing a single individual, composed of a partial snout, a possible surangular, two centra, and several ribs and gastralia. Ammonites and belemnites place this locality within the Valdani-Luridum Ammonite subzones of the Ibex Ammonite Zone, lower Pliensbachian. We assign the new ichthyosaur specimen to the clade Leptonectidae, using a combination of features from the snout and teeth. This specimen indicates that large neoichthyosaurians were present in multiple places of the European archipelago in all stages of the Early Jurassic and suggests that the ichthyosaurian faunae of western Europe remained essentially similar across the Sinemurian-Pliensbachian interval.Malgré d’abondants fossiles, la qualité de l’enregistrement fossile des reptiles marins du Jurassique inférieur fluctue largement à travers le temps et l’espace. Les strates pliensbachiennes ont fourni très peu de fossiles de reptiles marins, singulièrement hors d’Angleterre, occultant l’évolution des reptiles marins durant la partie centrale du Jurassique inférieur. Nous rapportons une nouvelle localité pliensbachienne au Luxembourg, contenant une faune marine abondante et des restes d’ichthyosaures représentant probablement un seul individu composé d’un museau partiel, un possible surangulaire, deux centra, ainis que plusieurs côtes et gastralia. Les ammonites et les bélemnites placent cette localité au sein des sous-zones à ammonites Valdini-Luridum, zone Ibex, Pliensbachien inférieur. Nous attribuons le nouveau specimen d’ichtyosaure au clade Leptonectidae, en utilisant une combination de caractrères issus du museau et des dents. Ce specimen indique que de large néoichthyosaures étaient présents à de multiples endroits au sein de l’archipel européen durant chaque étage du Jurassique inférieur et suggère que les faunes d’ichtyosaures d’Europe de l’Ouest sont restées essentiellement similaires durant l’intervalle Sinémurien-Pliensbachien.Trotz zahlreicher Fossilien unterliegt die Vollständigkeit der fossilen Überlieferung von Meeresreptilien aus dem frühen Jura starken zeitlichen und geographischen Schwankungen. Die Schichten des Pliensbachium haben nur sehr wenige marine Reptilienreste hervorgebracht, vor allem außerhalb Englands. Aus diesem Grund ist die Entwicklung der Meeresreptilien während des mittleren Teils des frühen Juras verhältnismäßig wenig bekannt. Wir berichten über einen neuen Fundort aus dem Pliensbachium Luxemburgs, der eine reichhaltige Meeresfauna geliefert hat, darunter Ichthyosaurier-Überreste, die wahrscheinlich ein einzelnes Individuum darstellen, bestehend aus einem Teil der Schnauze, einem möglichen Surangular, zwei Wirbelzentren und mehreren Rippen und Gastralia. Anhand von Ammoniten und Belemniten lässt sich die Fundschicht in die Valdani-Luridum Ammoniten-Subzonen der Ibex Ammoniten-Zone im unteren Pliensbachium einordnen. Eine Kombination von Merkmalen der Schnauze und der Zähne erlaubt eine Einordnung des Ichthyosaurier-Exemplars in die Kladus Leptonectidae. Das Exemplar deutet darauf hin, dass große Neoichthyosaurier in allen Phasen des frühen Jura an mehreren Orten des europäischen Archipels vorkamen, und legt nahe, dass die Ichthyosaurier-Fauna Westeuropas während des Sinemurium-Pliensbachium im Wesentlichen ähnlich blieb
A novel series of positive modulators of the AMPA receptor : discovery and structure based hit-to-lead studies
Starting from an HTS derived hit 1, application of biostructural data facilitated rapid optimization to lead 22, a novel AMPA receptor modulator. This is the first demonstration of how structure based drug design can be exploited in an optimization program for a glutamate receptor
Characterization of N-acetyltransferase 1 and 2 polymorphisms and haplotype analysis for inflammatory bowel disease and sporadic colorectal carcinoma
<p>Abstract</p> <p>Background</p> <p>N-acetyltransferase 1 (NAT1) and 2 (NAT2) are polymorphic isoenzymes responsible for the metabolism of numerous drugs and carcinogens. Acetylation catalyzed by NAT1 and NAT2 are important in metabolic activation of arylamines to electrophilic intermediates that initiate carcinogenesis. Inflammatory bowel diseases (IBD) consist of Crohn's disease (CD) and ulcerative colitis (UC), both are associated with increased colorectal cancer (CRC) risk. We hypothesized that <it>NAT1 </it>and/or <it>NAT2 </it>polymorphisms contribute to the increased cancer evident in IBD.</p> <p>Methods</p> <p>A case control study was performed with 729 Caucasian participants, 123 CRC, 201 CD, 167 UC, 15 IBD dysplasia/cancer and 223 controls. <it>NAT1 </it>and <it>NAT2 </it>genotyping were performed using Taqman based techniques. Eight single nucleotide polymorphisms (SNPs) were characterized for <it>NAT1 </it>and 7 SNPs for <it>NAT2</it>. Haplotype frequencies were estimated using an Expectation-Maximization (EM) method. Disease groups were compared to a control group for the frequencies at each individual SNP separately. The same groups were compared for the frequencies of <it>NAT1 </it>and <it>NAT2 </it>haplotypes and deduced NAT2 phenotypes.</p> <p>Results</p> <p>No statistically significant differences were found for any comparison. Strong linkage disequilibrium was present among both the <it>NAT1 </it>SNPs and the <it>NAT2 </it>SNPs.</p> <p>Conclusion</p> <p>This study did not demonstrate an association between <it>NAT1 </it>and <it>NAT2 </it>polymorphisms and IBD or sporadic CRC, although power calculations indicate this study had sufficient sample size to detect differences in frequency as small as 0.05 to 0.15 depending on SNP or haplotype.</p
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