949 resultados para Quantitative methodology
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Comparative molecular fiels analysis (CoMFA) has been applied to the studies of the correlation of the N-nitroso compounds and their carcinogenic activities, The comparison of CoMFA results with different lattice spacing and different atom probes was investigated, CoMFA resulted in a quantitative description of the major steric and electrostatic field effects and gave significant new insights to factors governing potency.
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In this paper, the new topological indices A(x1)-A(x3) suggested in our laboratory and molecular connectivity indices have been applied to multivariate analysis in structure-property studies. The topological indices of twenty asymmetrical phosphono bisazo derivatives of chromotropic acid have been calculated. The structure-property relationships between colour reagents and their colour reactions with ytterbium have been studied by A(x1)-A(x3) indices and molecular connectivity indices with satisfactory results. Multiple regression analysis and neural networks were employed simultaneously in this study.
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Quantitative structure-toxicity models were developed that directly link the molecular structures of a et of 50 alkYlated and/or halogenated phenols with their polar narcosis toxicity, expressed as the negative logarithm of the IGC50 (50% growth inhibitor
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Carbonic anhydrase (CA), an enzyme that catalyzes the interconversion of CO2 and HCO3-, has a critical role in inorganic carbon acquisition in many kingdoms, including animals, plants, and bacteria. In this study, the full-length cDNA of the CA gene from Porphyra yezoensis Ueda (denoted as PyCA) was cloned by using an expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE). The nucleotide sequence of PyCA consists of 1,153 bp, including a 5' untranslated region (UTR) of 177 bp, a 3' UTR of 151 bp, and an open reading frame (ORF) of 825 bp that can be translated into a 274-amino-acid putative peptide with a molecular mass (M) of 29.8 kDa and putative isoelectric point (pI) of 8.51. The predicted polypeptide has significant homology to the beta-CA from bacteria and unicellular algae, such as Porphyridium purpureum. The mRNA in filamentous thalli, leafy thalli, and conchospores was examined, respectively, by real-time fluorescent quantitative PCR (qPCR), and the levels of PyCA are different at different stages of the life cycle. The lowest level of mRNA was observed in leafy thalli, and the level in filamentous thalli and in the conchospores was 4-fold higher and 10-fold higher, respectively.
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The shell traits and weight traits are measured in cultured populations of bay scallop, Argopecten irradians. The results of regression analysis show that the regression relationships for all the traits are significant (P < 0.01). The correlative coefficients between body weight, as well as tissue weight with shell length, shell height and shell width are significant (P < 0.05). But the correlative coefficients between the anterior and posterior auricle length with body weight as well as tissue weight are not significant (P > 0.05). The multiple regression equation is obtained to estimate live body weight and tissue weight. The above traits except anterior and posterior auricle length are used for the growth and production comparison among three cultured populations, Duncan's new multiple range procedure analysis shows that all the traits in the Lingshuiqiao (LSQ) population are much more significant than those of the other two populations (P < 0.01), and there is no significant difference between the Qipanmo (QPM) and Dalijia (DLJ) populations in all traits (P > 0.05). The results indicate that the LSQ population has a higher growth rate and is expected to be more productive than the other two populations.
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A simple and convenient protocol for the cryopreservation of the flounder (Paralichthys olivaceus) sperm was established for "on the spot" cryopreservation of large quantities of semen. The use of three cryoprotectants, dimethyl sulphoxide (DMSO), glycerol (Gly) and methanol was tested in the method. The percentage of motile sperm present in semen after it had been frozen and thawed in the presence of DMSO, Gly or methanol was 60.5 +/- 3.6, 79.17 +/- 4.5 and 13.25 +/- 4.7%, respectively. The fertilization rates of this sperm were 67.06 +/- 15.1, 76.20 +/- 10.0 and 44.93 +/- 22.6%, while the hatching rates of eggs fertilized with this sperm were 37.40 +/- 8.3, 48.18 +/- 25.7 and 23.35 +/- 10.8%, respectively. It was found that Gly and DMSO were better cryoprotectants than methanol, with Gly giving the best overall results. Under scanning electron microscopy, it could be seen that while the majority of the frozen-thawed sperm remained morphologically normal, some exhibited lost or dilated mitochondria, swollen mid-pieces, broken tails, or damaged cell membrane, which probably caused the decrease in motility and fertility of the frozen-thawed sperm. (C) 2003 Elsevier Science Inc. All rights reserved.
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The locations and effects of quantitative trait loci (QTL) were estimated for nine characters for growth-related traits in the Pacific abalone (Haliotis discus hannai Ino) using a randomly amplified polymorphic DNA (RAPD), amplification fragment length polymorphism (AFLP) and SSR genetic linkage map. Twenty-eight putatively significant QTLs (LOD > 2.4) were detected for nine traits (shell length, shell width, total weight, shell weight, weight of soft part, muscle weight, gonad and digestive gland weight, mantle weight and gill weight). The percentage of phenotypic variation explained by a single QTL ranged from 8.0% to 35.9%. The significant correlations (P < 0.001) were found among all the growth-related traits, and Pearson's correlation coefficients were more than 0.81. For the female map, the QTL for growth were concentrated on groups 1 and 4 linkage maps. On the male map, the QTL that influenced growth-related traits gathered on the groups 1 and 9 linkage maps. Genetic linkage map construction and QTL analysis for growth-related traits are the basis for the marker-assisted selection and will eventually improve production and quality of the Pacific abalone.
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We constructed genetic linkage maps for the bay scallop Argopecten irradians using AFLP and microsatellite markers and conducted composite interval mapping (CIM) of body-size-related traits. Three hundred seventeen AFLP and 10 microsatellite markers were used for map construction. The female parent map contained 120 markers in 15 linkage groups, spanning 479.6 cM with an average interval of 7.0 cM. The male parent map had 190 markers in 17 linkage groups, covering 883.8 cM at 7.2 cM per marker. The observed coverage was 70.4% for the female and 81.1% for the male map. Markers that were distorted toward the same direction were closely linked to each other on the genetic maps, suggesting the presence of genes important for survival. Six size-related traits, shell length, shell height, shell width, total weight, soft tissue weight, and shell weight, were measured for QTL mapping. The size data were significantly correlated with each other. We subjected the data, log transformed firstly, to a principle component analysis and use the first principle component for QTL mapping. CIM analysis revealed one significant QTL (LOD=2.69, 1000 permutation, P<0.05) in linkage group 3 on the female parent map. The mapping of size-related QTL in this study raises the possibility of improving the growth of bay scallops through marker-assisted selection. (c) 2007 Published by Elsevier B.V.
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The aim of this study was to optimize the cryopreservation protocols for the sperm of red seabream, Pagrus major. The 2-mL cryovials and programmable freezer were employed for cryopreservation. Six extenders, six cryoprotectants in various concentrations ranging from 6 to 20% (v/v), four cooling rates, and three thawing temperatures were evaluated by postthaw sperm motility and fertility. The ratio of sperm to egg for postthaw sperm fertilization trials was experimentally standardized and was optimal at 500:1. The best motility of postthaw sperm (79.4 +/- 4.7% to 88.6 +/- 8.0%), fertilization rates (89.6 +/- 2.9 to 95.6 +/- 1.9%), and hatching rates (85.3 +/- 5.1% to 91.4 +/- 4.3%) were achieved when Cortland extender, dimethyl sulfoxide (15, 18, and 20%) or ethylene glycol (9, 12%) as cryoprotectants, 20 C/min as the cooling rate, and 40 C as the thawing temperature were employed. Moreover, the results on embryonic development were not significantly different between cryopreserved sperm and fresh sperm during incubation process. In conclusion, these methods of cryopreservation of red seabream sperm are suitable for routine aquaculture application and preservation of genetic resources.
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以图书馆学情报学期刊中较有影响的核心刊物之一《情报理论与实践》为依据,通过对其1995~2004年刊载的有关我国图书馆学情报学方法论研究论文的计量分析,描述出我国图书馆学情报学方法论研究的发展脉络,指出了其中的问题,希望反映出我国图书馆学情报学方法论的应用情况。
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PetroChina and other national petroleum incorporations need rigorous procedures and practical methods in risk evaluation and exploration decision at home and abroad to safeguard their international exploration practice in exploration licence bidding, finding appropriate ratio of risk sharing with partners, as well as avoiding high risk projects and other key exploration activities. However, due to historical reasons, we are only at the beginning of a full study and methodology development in exploration risk evaluation and decision. No rigorous procedure and practical methods are available in our exercises of international exploration. Completely adopting foreign procedure, methods and tools by our national incorporations are not practical because of the differences of the current economic and management systems in China. The objective of this study is to establish a risk evaluation and decision system with independent intellectual property right in oil and gas exploration so that a smooth transition from our current practice into international norm can take place. The system developed in this dissertation includes the following four components: 1. A set of quantitative criteria for risk evaluation is derived on the basis of an anatomy of the parameters from thirty calibration regions national wide as well as the characteristics and the geological factors controlling oil and gas occurrence in the major petroleum-bearing basins in China, which provides the technical support for the risk quantification in oil and gas exploration. 2. Through analysis of existing methodology, procedure and methods of exploration risk evaluation considering spatial information are proposed. The method, utilizing Mahalanobis Distance (MD) and fuzzy logic for data and information integration, provides probabilistic models on the basis of MD and fuzzy logic classification criteria, thus quantifying the exploration risk using Bayesian theory. A projection of the geological risk into spatial domain provides a probability map of oil and gas occurrence in the area under study. The application of this method to the Nanpu Sag shows that this method not only correctly predicted the oil and gas occurrence in the areas where Beibu and Laoyemiao oil fields are found in the northwest of the onshore area, but also predicted Laopu south, Nanpu south and Hatuo potential areas in the offshore part where exploration maturity was very low. The prediction of the potential areas are subsequently confirmed by 17 exploration wells in the offshore area with 81% success, indicating this method is very effective for exploration risk visualization and reduction. 3. On the basis of “Methods and parameters of economic evaluation for petroleum exploration and development projects in China”, a ”pyramid” method for sensitivity analysis was developed, which meets not only the need for exploration target evaluation and exploration decision at home, but also allows a transition from our current practice to international norm in exploration decision. This provides the foundation for the development of a software product “Exploration economic evaluation and decision system of PetroChina” (EDSys). 4. To solve problem in methodology of exploration decision, effort was made on the method of project portfolio management. A drilling decision method was developed employing the concept of geologically risked net present value. This method overcame the dilemma of handling simultaneously both geological risk and portfolio uncertainty, thus casting light into the application of modern portfolio theory to the evaluation of high risk petroleum exploration projects.
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Reformed basin is a basin that underwent multiple immense reformation after the sedimentary stage, the major geologic elements of the petroleum system in the prototyped basin are destroyed to a certain extent, and their petroleum system has been reconstructed. This type of basin is frequently found in the course of exploration both home and abroad. In China, especially in the western and southern part of China, the basins in which oil explorations have been conducted are mostly reformed basins. The reformed basins from Paleozoic, Late Mesozoic to Cenozoic are widely distributed in West and South China. They are, and moreover, will be a challenge for oil and gas exploration. The conventional investigation and exploration techniques used in the slightly reconstructed basin just don't work well when facing the reformed basin. Therefore, the study on the reformed basin, especially the study on the pool-forming mechanism and reservoir prediction becomes a focus and one of difficulties for the geologists overseas and domestic. Yingen-Ejinaqi Basin is a typical case of the Late Mesozoic and Cenozoic reformed basins in China. It locates in West China and is a exploration frontier with difficulties and no break through is made for years. A comprehensive research on it will be of significance for oil and gas exploration in similar basins of China. The late research for reformed basin in China now is mainly concentrated on basin classification, formation mechanism, geologic features, and survey technique, distribution regularity of oil accumulation and its dominating factors, assessment of oil exploration prospect and target zones, etc. On the other hand, the study on the pool-forming mechanism and reservoir prediction seems insufficient in systematization, and the research is deficient in methodology and combination of qualitative and quantitative studies, as well as the application of the new theory and techniques. The current efforts are mainly directed to structures (faults), sedimentation, the relationship between reservoir evolution and oil accumulation, and some other relevant fields. However, the application of the new theory and techniques seems to be insufficient such as petroleum system, pool-forming dynamics, fluid pressure compartment, and basin simulation, etc. So is the dynamic and integrated research. As a result, incomplete knowledge and understandings derived from the research on pool-forming mechanism and reservoir prediction often do not accord with rea-lity of the basin. The study and exploration under the guidance of this knowledge will inevitably lead to errors and failure. This paper, based on the previous study of the other geologists on reformed basins, with emphasis on "wholeness or systematic, dynamic and integrated" research, presents a reverse thinking of beginning from conserved units in the basin and the combination of qualitative and quantitative study with new theory and technique by building a geological model. The paper also puts forward a new thought for studying the oil & gas accumulation and reservoir prediction , and establishes a new research system for reformed basin. It is verified by the known reservoir and oil accumulation area in the basin and has a practical value for use and reference. The new ideas and achievements in this research are as following: 1.This is the first time that the system for studying the reformed basin and its pool-forming mechanism and reservoir prediction is presented. A reverse thinking and combination of qualitative & quantitative are applied here with emphasis on "wholeness or systematic, dynamic and integrated" research, new theory, techniques & methods comprehensive use and geologic models building. 2. Identifying criterion and methods, classifying schemes, and denominating principles for the conserved units of reformed basins are presented in this paper. The geologic model of conserved units of Yingen-Ejinaqi Basin has been built. It is a practical method when combined with the traditional way for basin survey and the conserved units study. 3.The dynamic sources of basin deformation are believed to be stress, gravity and thermodynamics. The stress and gravity are key factors in basin deformation and pool forming, especially stress. Scientific proof is provided by classifying the functional type, style and range of the stress, gravity and thermodynamics. 4.The pool forming and reservoir distribution of Yingen-Ejinaqi Basin are controlled by multiple factors or geologic conditions or/and co-controlled by both of them. The qualitative and quantitative research on petroleum system and basin modeling will help us understand and determine the pool-forming period of the conserved unit (timing), the oil migrating direction (orientation), the oil accumulating region (location), the oil distributing border (bordering) and the size of oil accumulation (quantification). Thus the pool-forming and distribution zones can be predicted. 5.Three generating modes (reform-succession type, reform-destroyed type and reform-regenerating type or reform-newborn type) of pool forming for reformed basins are presented here, together with the inner relationships between basin deformation type, overlapping style and pool-forming modes. The pool-forming modes are determined by deformation type and overlapping style. Reservoir distribution will be predicted based on the modes and other concrete pool-forming conditions. 6.The evaluation methods of the conserved units and zones and the parameter selection are reliable in optimal selecting of target zones. The technical terms, new ideas and methods for the study of reformed basins, the pool-forming mechanism and reservoir prediction are presented in this paper. The concepts and terms, the identifying criterion, the denominating principles, the generating modes for pool forming, the methods of reservoir prediction, and the evaluation techniques for conserved units and zones can be used for reference in studies on the petroleum exploration of reformed basins in China and abroad. It serves as a typical example for further research of the reformed basins and the geologic regulations of oil accumulation. It has a practical value of use and reference. The future research in the field of pool-forming mechanism of the reformed basins may well be on the process simulation of pool-forming dynamics of the reformed basins. Experimental work has been conducted to simulate the processes by using quantitative and qualitative methods combined. The further study in this field calls for more efforts.
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Fluvial Sedimentation of alluvial facies prevailed during the Late Jrassic in the Minhe Basin.On the basis of the study of sedimentary facies of the Upper Jurassic series.this paper focuses on the river types suing the "Architecture Element" analysis method proposed by Miall,and calculated all the quantitative parameters to reflect the characteristics of the stream channel geometry and hydrodynamic conditions of paleo-rivers with the equations of ethrideg,schumm et al.Finally,we discussed the characteristics of environmental evolution of palsorivers on the quantitative basis.Our conclusion indicates that the evolution of paleo-rivers during the Late Jurassic,from early to late,shows such a tendency as alluvial fan river→ braid river→alluvial fan river→mid-sinuoisty river→ high-sinuosity river.