4,105 research outputs found
Animals and Robbers
No full textTale told by Jim Couch of Harlan County, Kentucky and recorded by Leonard Roberts [1953]
Love Story
No full textTale told by Felix Turner of Clay County, Kentucky and recorded by Leonard Roberts [Fall 1949.
A functional LR parser
No full textAbstractA purely functional implementation of LR(0) parsers is given, together with a simple correctness proof. For non-LR(0) grammars its time complexity is cubic if the functions that constitute the parser are implemented as memo-functions, i.e. functions that memorize the results of previous invocations. For LR(0) grammars, our algorithm is closely related to the recursive ascent parsers recently discovered by Kruseman Aretz (1988), Barnard and Cordy (1988) and Roberts (1988)
A functional LR parser
No full textA purely functional implementation of LR(0) parsers is given, together with a simple correctness proof. For non-LR(0) grammars its time complexity is cubic if the functions that constitute the parser are implemented as memo-functions, i.e. functions that memorize the results of previous invocations. For LR(0) grammars, our algorithm is closely related to the recursive ascent parsers recently discovered by Kruseman Aretz (1988), Barnard and Cordy (1988) and Roberts (1988)
The role of Ruditapes philippinarum glutathione transferases in the metabolism of microcystin-LR
No full textNo abstracts are to be cited without prior reference to the author. Glutathione transferases (GSTs) are phase II enzymes involved in the microcystin (MC) induced detoxication processes. In this study we analyze and compare the metabolism of MC-LR by the cytosolic GSTs from gills and hepatopancreas of Ruditapes philippinarum. Cytosolic GSTs were purified by glutathione (GSH)–agarose affinity chromatography from exposed and non-exposed bivalves to MC-LR (100 µg/L) representing the inducible and constitutive (Basal) GST fractions, respectively. For each mixture, we examined the in vitro cytosolic GST inhibition efficiency of the conjugation of CDNB to GSH by MC-LR and characterize the inhibition mechanism. Results support the important role of GST enzymes in detoxification of MCs in bivalve mollusk
Transcriptional responses of glutathione transferase genes in Ruditapes philippinarum exposed to microcystin-LR
No full textNo abstracts are to be cited without prior reference to the author. Microcystins (MCs) are potent hepatotoxins produced by bloom-forming species of toxic cyanobacteria. Among these, MC-LR is the most commonly found and toxic variant. Bivalves, due to their benthic and sedentary mode of life, are one of the most threatened organisms by these environmental stressors. Glutathione transferases (GSTs) play a major role in cellular defense against MCs toxicity. The aim of this study was to compare the relative changes of gene expression of the different GSTs isoforms in mollusc bivalves exposed to MCs. The time-dependent changes of relative transcription abundance of several GST isoforms in parallel with enzymatic activity of total GST were investigated in gills and hepatopancreas of Ruditapes philippinarum exposed to dissolved MC-LR. The relative changes of gene expression and enzyme activity were analyzed by quantitative real-time PCR and colorimetric assays respectively. We found that MC-LR could affect the transcriptional activities of these detoxification enzymes in gills and hepatopancreas of the tested bivalves. Most GST isoforms showed differential response profiles depending on the concentrations of MC-LR and exposure times for clams. These results highlight the important role of GSTs in counteracting the potential deleterious effects induced by MCs in bivalve
Fast removal of cyanobacterial toxin microcystin-LR by a low-cytotoxic microgel-Fe(III) complex
No full textEutrophication has become a serious environmental threat throughout the world. In particular, the presence of cyanobacteria toxins, especially microcystins (MCs), has become a severe problem. Inhibition of Microcystis growth in water resources is the most effective way to reduce MCs, but it is a long-term investment. In the present study, a microgel-Fe(III) complex was developed for the fast removal of MC-LR. The microgel-Fe(III) characteristics and the MC-LR removal dynamics in Milli-Q water and natural water were evaluated. The removal efficiency negatively correlated to the initial MC-LR concentration and pH value (2.0-11.5), but the kinetics was not significantly influenced. The presence of natural organic matter (NOM) in water slightly reduced MC-LR removal using microgel-Fe(III). In addition, microgel-Fe(III) removed 98.99% of MC-LR in 12 min, while for activated carbon, it took 15-24 h to reach equilibrium. Furthermore, methanol was found to regenerate the microgel-Fe(III) after MC-LR removal for at least five regeneration cycles. Finally, the microgel-Fe(III) material was made into a membrane so that MCs could be removed by filtration. Therefore, microgel-Fe(III) is an effective technology and has a great potential in removing MC-LR from drinking water resources. (C) 2011 Elsevier Ltd. All rights reserved.Eutrophication has become a serious environmental threat throughout the world. In particular, the presence of cyanobacteria toxins, especially microcystins (MCs), has become a severe problem. Inhibition of Microcystis growth in water resources is the most effective way to reduce MCs, but it is a long-term investment. In the present study, a microgel-Fe(III) complex was developed for the fast removal of MC-LR. The microgel-Fe(III) characteristics and the MC-LR removal dynamics in Milli-Q water and natural water were evaluated. The removal efficiency negatively correlated to the initial MC-LR concentration and pH value (2.0-11.5), but the kinetics was not significantly influenced. The presence of natural organic matter (NOM) in water slightly reduced MC-LR removal using microgel-Fe(III). In addition, microgel-Fe(III) removed 98.99% of MC-LR in 12 min, while for activated carbon, it took 15-24 h to reach equilibrium. Furthermore, methanol was found to regenerate the microgel-Fe(III) after MC-LR removal for at least five regeneration cycles. Finally, the microgel-Fe(III) material was made into a membrane so that MCs could be removed by filtration. Therefore, microgel-Fe(III) is an effective technology and has a great potential in removing MC-LR from drinking water resources. (C) 2011 Elsevier Ltd. All rights reserved
Incremental Scannerless Generalized LR Parsing
No full textThe Scannerless Generalized LR (SGLR) parsing algorithm supports the development of composed languages seamlessly but does not support incremental parsing. The Incremental Generalized LR (IGLR) parsing algorithm, on the other hand, does not support the seamless composition of languages. This thesis presents the Incremental Scannerless Generalized LR (ISGLR) parsing algorithm and investigates the effects of combining the SGLR and IGLR parsing algorithms. While the algorithmic differences are orthogonal, the fact that scannerless parsing relies on non-deterministic parsing for disambiguation has a negative impact on incrementality. Nonetheless, we show that the ISGLR parsing algorithm performs better than the batch SGLR parsing algorithm in typical scenarios. On average, the ISGLR parser can reuse 99% of a previous parse result. When parsing from scratch, the ISGLR parser has a 24% run time overhead compared to the SGLR parser, but when parsing incrementally for changes that are smaller than 1% of the input size on average, it has a 9× speedup.Successor of https://doi.org/10.1145/3359061.3361085Computer Scienc
TOXIC EFFECTS OF MICROCYSTIN-LR ON MICE ERYTHROCYTES in vitro
No full textHaematological abnormalities have been verified in patients intoxicated by microcystins (MCs) in haemodialysis unit in Caruaru, Brazil, and 60 patients died. In our previous studies, obvious anemia has been determined in rabbit after in vivo exposure to microcystins. As to the cause of the anemia, except for hematopoiesis obstacles, we hypothesized that microcystins result in erythrocyte destruction. In the present study, Kunming mice erythrocytes in vitro were incubated with 1, 10, 100 and 1000 nM microcystin-LR at 37 degrees C. Lipid peroxidation, haemolysis, cell morphology, antioxidative response and some biochemical biomarkers were measured. The results showed that the level of lipid peroxidation significantly increased in microcystin-LR treatment groups. The level of glutathione and activities of glutathione peroxidase, glutathione-S-transferase and superoxide dismutase were significantly increased after incubation with microcystin-LR at 12, 24 and 48 h. Also, significant decreases in activities of acetylcholinesterase, Na+-K+-ATPase and Ca2+-Mg2+-ATPase were observed. Obvious increases of haemolysis were determined in 10, 100 and 1000 nM groups from 12 to 48 h. Additionally, abnormal erythrocytes with bleb-bing and notched cell membrane were observed in both 100 and 1000 nM groups. It is presumed that microcystin-LR triggers lipid peroxidation of erythrocytes and oxidative stress destroys the structure of cell membrane, leading to alterations of antioxidative enzymes and biochemical indicators. Our results demonstrate that in vitro exposure to microcystin-LR resulted in damage of mice erythrocytes.Haematological abnormalities have been verified in patients intoxicated by microcystins (MCs) in haemodialysis unit in Caruaru, Brazil, and 60 patients died. In our previous studies, obvious anemia has been determined in rabbit after in vivo exposure to microcystins. As to the cause of the anemia, except for hematopoiesis obstacles, we hypothesized that microcystins result in erythrocyte destruction. In the present study, Kunming mice erythrocytes in vitro were incubated with 1, 10, 100 and 1000 nM microcystin-LR at 37 degrees C. Lipid peroxidation, haemolysis, cell morphology, antioxidative response and some biochemical biomarkers were measured. The results showed that the level of lipid peroxidation significantly increased in microcystin-LR treatment groups. The level of glutathione and activities of glutathione peroxidase, glutathione-S-transferase and superoxide dismutase were significantly increased after incubation with microcystin-LR at 12, 24 and 48 h. Also, significant decreases in activities of acetylcholinesterase, Na+-K+-ATPase and Ca2+-Mg2+-ATPase were observed. Obvious increases of haemolysis were determined in 10, 100 and 1000 nM groups from 12 to 48 h. Additionally, abnormal erythrocytes with bleb-bing and notched cell membrane were observed in both 100 and 1000 nM groups. It is presumed that microcystin-LR triggers lipid peroxidation of erythrocytes and oxidative stress destroys the structure of cell membrane, leading to alterations of antioxidative enzymes and biochemical indicators. Our results demonstrate that in vitro exposure to microcystin-LR resulted in damage of mice erythrocytes
Construction Methods of LR Parsers
Get PDFThis paper presents five different LR parser generators and an error recovery method which is derived directly from the LR parser. The parsers presented include the original LR (1) parser defined by Knuth. The SLR(1) and LALR(1) parsers defined by DeRemer, and the weak and strong compatible LR parsers presented by Pager. All five parsers have been implemented by the author using two programs. Furthermore, the implementation of the SLR (1) parser generator includes an error recovery method and produces an SLR(1) parser with error recovery built in
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