Journal articles: 'QSSA'

1

Wu, Fangxi, Xi Luo, Lingqiang Wang, Yidong Wei, Jianguo Li, Huaan Xie, Jianfu Zhang, and Guosheng Xie. "Genome-Wide Association Study Reveals the QTLs for Seed Storability in World Rice Core Collections." Plants 10, no. 4 (April 20, 2021): 812. http://dx.doi.org/10.3390/plants10040812.

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Seed storability is a main agronomically important trait to assure storage safety of grain and seeds in rice. Although many quantitative trait loci (QTLs) and associated genes for rice seed storability have been identified, the detailed genetic mechanisms of seed storability remain unclear in rice. In this study, a genome-wide association study (GWAS) was performed in 456 diverse rice core collections from the 3K rice genome. We discovered the new nine QTLs designated as qSS1-1, qSS1-2, qSS2-1, qSS3-1, qSS5-1, qSS5-2, qSS7-1, qSS8-1, and qSS11-1. According to the analysis of the new nine QTLs, our results could well explain the reason why seed storability of indica subspecies was superior to japonica subspecies in rice. Among them, qSS1-2 and qSS8-1 were potentially co-localized with a known associated qSS1/OsGH3-2 and OsPIMT1, respectively. Our results also suggest that pyramiding breeding of superior alleles of these associated genes will lead to new varieties with improved seed storability in the future.

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Kotte, Ann-Kathrin, Oliver Severn, Zak Bean, Katrin Schwarz, Nigel P. Minton, and Klaus Winzer. "RRNPP-type quorum sensing affects solvent formation and sporulation in Clostridium acetobutylicum." Microbiology 166, no. 6 (June 1, 2020): 579–92. http://dx.doi.org/10.1099/mic.0.000916.

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The strictly anaerobic bacterium Clostridium acetobutylicum is well known for its ability to convert sugars into organic acids and solvents, most notably the potential biofuel butanol. However, the regulation of its fermentation metabolism, in particular the shift from acid to solvent production, remains poorly understood. The aim of this study was to investigate whether cell–cell communication plays a role in controlling the timing of this shift or the extent of solvent formation. Analysis of the available C. acetobutylicum genome sequences revealed the presence of eight putative RRNPP-type quorum-sensing systems, here designated qssA to qssH, each consisting of an RRNPP-type regulator gene followed by a small open reading frame encoding a putative signalling peptide precursor. The identified regulator and signal peptide precursor genes were designated qsrA to qsrH and qspA to qspH, respectively. Triplicate regulator mutants were generated in strain ATCC 824 for each of the eight systems and screened for phenotypic changes. The qsrB mutants showed increased solvent formation during early solventogenesis and hence the QssB system was selected for further characterization. Overexpression of qsrB severely reduced solvent and endospore formation and this effect could be overcome by adding short synthetic peptides to the culture medium representing a specific region of the QspB signalling peptide precursor. In addition, overexpression of qspB increased the production of acetone and butanol and the initial (48 h) titre of heat-resistant endospores. Together, these findings establish a role for QssB quorum sensing in the regulation of early solventogenesis and sporulation in C. acetobutylicum .

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Wen, He, Huifang Dai, Zhaosheng Teng, Yuxiang Yang, and Fuhai Li. "Performance Comparison of Windowed Interpolation FFT and Quasisynchronous Sampling Algorithm for Frequency Estimation." Mathematical Problems in Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/745830.

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The DFT-based frequency estimations have inherent limitations such as spectral leakage and picket-fence effect due to asynchronous sampling. This paper focuses on comparing the windowed interpolation FFT (WIFFT) and quasisynchronous sampling algorithm (QSSA) for frequency estimation. The WIFFT uses windows to reduce spectral leakage and employs interpolation algorithm to eliminate picket-fence effect. And the QSSA utilizes quasisynchronous weighted iterations for frequency estimation. The accuracy and time complexity of WIFFT and QSSA are theoretically studied. Computer simulations of frequency estimations with noise and fluctuations by using WIFFT and QSSA are performed. Simulations results show that the wideband noise sensitivity of QSSA is lower than that of WIFFT. However, the WIFFT exhibits less time complexity than QSSA.

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Boulier, François, and François Lemaire. "Differential algebra and QSSA methods in biochemistry." IFAC Proceedings Volumes 42, no. 10 (2009): 33–38. http://dx.doi.org/10.3182/20090706-3-fr-2004.00004.

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5

Sun, Qibo, Shangguang Wang, Hua Zou, and Fangchun Yang. "QSSA: A QoS-aware Service Selection Approach." International Journal of Web and Grid Services 7, no. 2 (2011): 147. http://dx.doi.org/10.1504/ijwgs.2011.040446.

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6

Gao, Hongyuan, Yangyang Hou, Shibo Zhang, and Ming Diao. "An Efficient Approximation for Nakagami-mQuantile Function Based on Generalized Opposition-Based Quantum Salp Swarm Algorithm." Mathematical Problems in Engineering 2019 (August 14, 2019): 1–13. http://dx.doi.org/10.1155/2019/8291063.

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With the further research in communication systems, especially in wireless communication systems, a statistical model called Nakagami-mdistribution appears to have better performance than other distributions, including Rice and Rayleigh, in explaining received faded envelopes. Therefore, the Nakagami-mquantile function plays an important role in numerical calculations and theoretical analyses for wireless communication systems. However, it is quite difficult to operate numerical calculations and theoretical analyses because Nakagami-mquantile function has no exact closed-form expression. In order to obtain the closed-form expression that is able to fit the curve of Nakagami-mquantile function as well as possible, we adopt the method of curve fitting in this paper. An efficient expression for approximating the Nakagami-mquantile function is proposed first and then a novel heuristic optimization algorithm—generalized opposition-based quantum salp swarm algorithm (GO-QSSA)—which contains quantum computation, intelligence inspired by salp swarm and generalized opposition-based learning strategy in quantum space, to compute the coefficients of the proposed expression. Meanwhile, we compare GO-QSSA with three swarm intelligence algorithms: artificial bee colony algorithm (ABC), particle swarm optimization algorithm (PSO), and salp swarm algorithm (SSA). The comparing simulation results reveal that GO-QSSA owns faster convergence speed than PSO, ABC, and SSA. Moreover, GO-QSSA is capable of computing more accurately than traditional algorithms. In addition, the simulation results show that compared with existing curve-fitting-based methods, the proposed expression decreases the fitting error by roughly one order of magnitude in most cases and even higher in some cases. Our approximation is proved to be simple and efficient.

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7

Whitehouse, L. E., A. S. Tomlin, and M. J. Pilling. "Systematic reduction of complex tropospheric chemical mechanisms, Part I: sensitivity and time-scale analyses." Atmospheric Chemistry and Physics 4, no. 7 (October 5, 2004): 2025–56. http://dx.doi.org/10.5194/acp-4-2025-2004.

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Abstract. Explicit mechanisms describing the complex degradation pathways of atmospheric volatile organic compounds (VOCs) are important, since they allow the study of the contribution of individual VOCS to secondary pollutant formation. They are computationally expensive to solve however, since they contain large numbers of species and a wide range of time-scales causing stiffness in the resulting equation systems. This paper and the following companion paper describe the application of systematic and automated methods for reducing such complex mechanisms, whilst maintaining the accuracy of the model with respect to important species and features. The methods are demonstrated via application to version 2 of the Leeds Master Chemical Mechanism. The methods of Jacobian analysis and overall rate sensitivity analysis proved to be efficient and capable of removing the majority of redundant reactions and species in the scheme across a wide range of conditions relevant to the polluted troposphere. The application of principal component analysis of the rate sensitivity matrix was computationally expensive due to its use of the decomposition of very large matrices, and did not produce significant reduction over and above the other sensitivity methods. The use of the quasi-steady state approximation (QSSA) proved to be an extremely successful method of removing the fast time-scales within the system, as demonstrated by a local perturbation analysis at each stage of reduction. QSSA species were automatically selected via the calculation of instantaneous QSSA errors based on user-selected tolerances. The application of the QSSA led to the removal of a large number of alkoxy radicals and excited Criegee bi-radicals via reaction lumping. The resulting reduced mechanism was shown to reproduce the concentration profiles of the important species selected from the full mechanism over a wide range of conditions, including those outside of which the reduced mechanism was generated. As a result of a reduction in the number of species in the scheme of a factor of 2, and a reduction in stiffness, the computational time required for simulations was reduced by a factor of 4 when compared to the full scheme.

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8

Chen, Rongzhong, Chen Dong, Yin Ye, Zhenyi Chen, and Yanhua Liu. "QSSA: Quantum Evolutionary Salp Swarm Algorithm for Mechanical Design." IEEE Access 7 (2019): 145582–95. http://dx.doi.org/10.1109/access.2019.2945842.

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9

Whitehouse, L. E., A. S. Tomlin, and M. J. Pilling. "Systematic reduction of complex tropospheric chemical mechanisms using sensitivity and time-scale analyses." Atmospheric Chemistry and Physics Discussions 4, no. 4 (July 8, 2004): 3721–83. http://dx.doi.org/10.5194/acpd-4-3721-2004.

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Abstract. Explicit mechanisms describing the complex degradation pathways of atmospheric volatile organic compounds (VOCs) are important, since they allow the study of the contribution of individual VOCS to secondary pollutant formation. They are computationally expensive to solve however, since they contain large numbers of species and a wide range of time-scales causing stiffness in the resulting equation systems. This paper and the following companion paper describe the application of systematic and automated methods for reducing such complex mechanisms, whilst maintaining the accuracy of the model with respect to important species and features. The methods are demonstrated via application to version 2 of the Leeds Master Chemical Mechanism. The methods of local concentration sensitivity analysis and overall rate sensitivity analysis proved to be efficient and capable of removing the majority of redundant reactions and species in the scheme across a wide range of conditions relevant to the polluted troposphere. The application of principal component analysis of the rate sensitivity matrix was computationally expensive due to its use of the decomposition of very large matrices, and did not produce significant reduction over and above the other sensitivity methods. The use of the quasi-steady state approximation (QSSA) proved to be an extremely successful method of removing the fast time-scales within the system, as demonstrated by a local perturbation analysis at each stage of reduction. QSSA species were automatically selected via the calculation of instantaneous QSSA errors based on user-selected tolerances. The application of the QSSA led to the removal of a large number of alkoxy radicals and excited Criegee bi-radicals via reaction lumping. The resulting reduced mechanism was shown to reproduce the concentration profiles of the important species selected from the full mechanism over a wide range of conditions, including those outside of which the reduced mechanism was generated. As a result of a reduction in the number of species in the scheme of a factor of 2, and a reduction in stiffness, the computational time required for simulations was reduced by a factor of 4 when compared to the full scheme.

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10

Lu, Tzyy-Chyang, and Jyh-Ching Juang. "Quantum-inspired space search algorithm (QSSA) for global numerical optimization." Applied Mathematics and Computation 218, no. 6 (November 2011): 2516–32. http://dx.doi.org/10.1016/j.amc.2011.07.067.

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11

Shoji, Masakazu, Yoshio Morozumi, Hideyuki Aoki, and Takatoshi Miura. "A Reducing Method of a Detailed Reaction Mechanism Based on the QSSA Method." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 39, no. 11 (2006): 1182–90. http://dx.doi.org/10.1252/jcej.39.1182.

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12

Yu, Chunkan, Viatcheslav Bykov, and Ulrich Maas. "Global quasi-linearization (GQL) versus QSSA for a hydrogen–air auto-ignition problem." Physical Chemistry Chemical Physics 20, no. 16 (2018): 10770–79. http://dx.doi.org/10.1039/c7cp07213a.

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A recently developed automatic reduction method for systems of chemical kinetics, the so-called Global Quasi-Linearization (GQL) method, has been implemented to study and reduce the dimensions of a homogeneous combustion system.

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13

Xia, A. G., D. V. Michelangeli, and P. A. Makar. "Mechanism reduction for the formation of secondary organic aerosol for integration into a 3-dimensional regional air quality model: <i>α</i>-pinene oxidation system." Atmospheric Chemistry and Physics 9, no. 13 (July 7, 2009): 4341–62. http://dx.doi.org/10.5194/acp-9-4341-2009.

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Abstract. A detailed α-pinene oxidation mechanism was reduced systematically through the successive application of five mechanism reduction techniques. The resulting reduced mechanism preserves the ozone- and organic aerosol-forming properties of the original mechanism, while using less species. The methodologies employed included a directed relation graph method with error propagation (DRGEP, which removed a large number of redundant species and reactions), principal component analysis of the rate sensitivity matrix (PCA, used to remove unnecessary reactions), the quasi-steady-state approximation (QSSA, used to remove some QSS species), an iterative screening method (ISSA, which removes redundant species and reactions simultaneously), and a new lumping approach dependent on the hydrocarbon to NOx ratio (which reduced the number of species in mechanism subsets for specific hydrocarbon to NOx ranges). This multistage methodology results in a reduction ratio of 2.5 for the number of both species and reactions compared with the full mechanism. The simplified mechanism reproduces the important gas and aerosol phase species (the latter are examined in detail by individual condensing species as well as in classes according to four functional groups: PANs, nitrates, organic peroxides, and organic acids). The total SOA mass is also well represented in the condensed mechanism, to within 16% of the detailed mechanism under a wide range of conditions. The methodology described here is general, and may be used in general mechanism reduction problems.

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Xia, A. G., D. V. Michelangeli, and P. A. Makar. "Mechanism reduction for the formation of secondary organic aerosol for integration into a 3-dimensional regional Air Quality Model: <i>α</i>-pinene oxidation system." Atmospheric Chemistry and Physics Discussions 8, no. 4 (July 14, 2008): 13301–54. http://dx.doi.org/10.5194/acpd-8-13301-2008.

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Abstract. A detailed α-pinene oxidation mechanism was reduced systematically through the successive application of five mechanism reduction techniques. The resulting reduced mechanism preserves the ozone- and organic aerosol-forming properties of the original mechanism, while using less species. The methodologies employed included a directed relation graph method with error propagation (DRGEP, which removed a large number of redundant species and reactions), principal component analysis of the rate sensitivity matrix (PCA, used to remove unnecessary reactions), the quasi-steady-state approximation (QSSA, used to remove some QSS species), an iterative screening method (ISSA, which removes redundant species and reactions simultaneously), and a new lumping approach dependant on the hydrocarbon to NOx ratio (which reduced the number of species in mechanism subsets for specific hydrocarbon to NOx ranges). This multistage methodology results in a reduction ratio of 2.5 for the number of both species and reactions compared with the full mechanism. The simplified mechanism reproduces the important gas and aerosol phase species (the latter are examined in detail by individual condensing species as well as in classes according to four functional groups: PANs, nitrates, organic peroxides, and organic acids). The total SOA mass is also well represented in the condensed mechanism, to within 16% of the detailed mechanism under a wide range of conditions. The methodology described here is general, and may be used in general mechanism reduction problems.

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15

Hughes, Kevin J., Mike Fairweather, John F. Griffiths, Richard Porter, and Alison S. Tomlin. "The application of the QSSA via reaction lumping for the reduction of complex hydrocarbon oxidation mechanisms." Proceedings of the Combustion Institute 32, no. 1 (2009): 543–51. http://dx.doi.org/10.1016/j.proci.2008.06.064.

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16

Rebelo Pinto, Teresa, Joana Carneiro Pinto, Helena Rebelo-Pinto, and Teresa Paiva. "O sono em adolescentes portugueses: Proposta de um modelo tridimensional." Análise Psicológica 34, no. 4 (December 12, 2016): 339–52. http://dx.doi.org/10.14417/ap.1221.

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O sono é uma necessidade básica que influencia e é simultaneamente influenciada pela diversidade de atividades, papéis e contextos de vida, assumindo particular importância nos adolescentes. Apresenta-se um estudo com 400 alunos do 9º e 11º anos de escolaridade, de duas escolas da região de Lisboa, avaliados através do Questionário Sobre Sono para Adolescentes - QSSA. Os resultados quantitativos da caracterização do sono incidiram sobre hábitos, auto perceções e conhecimentos. Da exploração qualitativa dos fatores invocados por uma subamostra de 100 adolescentes como fundamento das suas auto perceções, emergiram as categorias de qualidade, importância e atitudes. Com base nestes resultados, propõe-se um modelo tridimensional acerca do sono dos adolescentes que contempla hábitos de sono, fatores pessoais e fatores ambientais.

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Bultinck, Patrick, Tom Kuppens, Xavier Gironés, and Ramon Carbó-Dorca. "Quantum Similarity Superposition Algorithm (QSSA): A Consistent Scheme for Molecular Alignment and Molecular Similarity Based on Quantum Chemistry." Journal of Chemical Information and Computer Sciences 43, no. 4 (July 2003): 1143–50. http://dx.doi.org/10.1021/ci0340153.

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TREVELYAN, P. M. J., C. ALMARCHA, and A. DE WIT. "Buoyancy-driven instabilities of miscible two-layer stratifications in porous media and Hele-Shaw cells." Journal of Fluid Mechanics 670 (January 31, 2011): 38–65. http://dx.doi.org/10.1017/s0022112010005008.

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Buoyancy-driven instabilities of a horizontal interface between two miscible solutions in the gravity field are theoretically studied in porous media and Hele-Shaw cells (two glass plates separated by a thin gap). Beyond the classical Rayleigh–Taylor (RT) and double diffusive (DD) instabilities that can affect such two-layer stratifications right at the initial time of contact, diffusive-layer convection (DLC) as well as delayed-double diffusive (DDD) instabilities can set in at a later time when differential diffusion effects act upon the evolving density profile starting from an initial step-function profile between the two miscible solutions. The conditions for these instabilities to occur can therefore be obtained only by considering time evolving base-state profiles. To do so, we perform a linear stability analysis based on a quasi-steady-state approximation (QSSA) as well as nonlinear simulations of a diffusion–convection model to classify and analyse all possible buoyancy-driven instabilities of a stratification of a solution of a given solute A on top of another miscible solution of a species B. Our theoretical model couples Darcy's law to evolution equations for the concentration of species A and B ruling the density of the miscible solutions. The parameters of the problem are a buoyancy ratio R quantifying the ratio of the relative contribution of B and A to the density as well as δ, the ratio of diffusion coefficients of these two species. We classify the region of RT, DD, DDD and DLC instabilities in the (R, δ) plane as a function of the elapsed time and show that, asymptotically, the unstable domain is much larger than the one captured on the basis of linear base-state profiles which can only obtain stability thresholds for the RT and DD instabilities. In addition the QSSA allows one to determine the critical time at which an initially stable stratification of A above B can become unstable with regard to a DDD or DLC mechanism when starting from initial step function profiles. Nonlinear dynamics are also analysed by a numerical integration of the full nonlinear model in order to understand the influence of R and δ on the dynamics.

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Tingas, Efstathios-Al, Dimitrios J. Diamantis, and Dimitris A. Goussis. "Issues arising in the construction of QSSA mechanisms: the case of reduced n-heptane/air models for premixed flames." Combustion Theory and Modelling 22, no. 6 (June 2018): 1049–83. http://dx.doi.org/10.1080/13647830.2018.1470333.

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Mukherjee, Debasmita, Lakshmi Narayan Guin, and Santabrata Chakravarty. "Dynamical Response of Atherosclerotic Plaque Through Mathematical Model." Biophysical Reviews and Letters 14, no. 02 (June 2019): 49–74. http://dx.doi.org/10.1142/s1793048019500036.

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The present paper concerns itself with the dynamical response of the formation of atherosclerotic plaque arising from the interactions among various cellular components in arteries. An appropriate mathematical model is framed to articulate the involvement of several key cellular components like LDLs, HDLs, radicals, oxidized LDLs, chemo-attractants, etc. in terms of a large system of nonlinear ordinary differential equations. The present dynamical model bears the potential to have global stability and hence it furnishes a comprehensible essence for in silico studies on the onset of atherosclerotic plaque. Quasi steady state approximation (QSSA) theory is inducted for reduction of the larger system to a smaller one compliant with an in-depth study regarding its stability and bifurcation analytically. Special emphasis is put on the significant role of arterial radius in the process of disposition of atherosclerotic plaque by contending with the variability of wall shear stress (WSS). The applicability of the model is validated through numerically computed results based on existing parameter values so as to ascertain the implications of the biochemical process of arteriosclerotic plaque formation.

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Whitehouse, L. E., A. S. Tomlin, and M. J. Pilling. "Systematic reduction of complex tropospheric chemical mechanisms, Part II: Lumping using a time-scale based approach." Atmospheric Chemistry and Physics 4, no. 7 (October 5, 2004): 2057–81. http://dx.doi.org/10.5194/acp-4-2057-2004.

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Abstract. This paper presents a formal method of species lumping that can be applied automatically to intermediate compounds within detailed and complex tropospheric chemical reaction schemes. The method is based on grouping species with reference to their chemical lifetimes and reactivity structures. A method for determining the forward and reverse transformations between individual and lumped compounds is developed. Preliminary application to the Leeds Master Chemical Mechanism (MCMv2.0) has led to the removal of 734 species and 1777 reactions from the scheme, with minimal degradation of accuracy across a wide range of test trajectories relevant to polluted tropospheric conditions. The lumped groups are seen to relate to groups of peroxy acyl nitrates, nitrates, carbonates, oxepins, substituted phenols, oxeacids and peracids with similar lifetimes and reaction rates with OH. In combination with other reduction techniques, such as sensitivity analysis and the application of the quasi-steady state approximation (QSSA), a reduced mechanism has been developed that contains 35% of the number of species and 40% of the number of reactions compared to the full mechanism. This has led to a speed up of a factor of 8 in terms of computer calculation time within box model simulations.

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Whitehouse, L. E., A. S. Tomlin, and M. J. Pilling. "Systematic lumping of complex tropospheric chemical mechanisms using a time-scale based approach." Atmospheric Chemistry and Physics Discussions 4, no. 4 (July 8, 2004): 3785–834. http://dx.doi.org/10.5194/acpd-4-3785-2004.

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Abstract. This paper presents a formal method of species lumping that can be applied automatically to intermediate compounds within detailed and complex tropospheric chemical reaction schemes. The method is based on grouping species with reference to their chemical lifetimes and reactivity structures. A method for determining the forward and reverse transformations between individual and lumped compounds is developed. Preliminary application to the Leeds Master Chemical Mechanism (MCMv2.0) has led to the removal of 734 species and 1777 reactions from the scheme, with minimal degradation of accuracy across a wide range of test trajectories relevant to polluted tropospheric conditions. The lumped groups are seen to relate to groups of peroxy acyl nitrates, nitrates, carbonates, oxepins, substituted phenols, oxeacids and peracids with similar lifetimes and reaction rates with OH. In combination with other reduction techniques, such as sensitivity analysis and the application of the quasi-steady state approximation (QSSA), a reduced mechanism has been developed that contains 35% of the number of species and 40% of the number of reactions compared to the full mechanism. This has led to a speed up of a factor of 8 in terms of computer calculation time within box model simulations.

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Li, Jianzhong, Li Yuan, Wei Li, and Kaichen Zhang. "Numerical Investigation of Combustion Characteristics of a Wave Rotor Combustor Based on a Reduced Reaction Mechanism of Ethylene." International Journal of Aerospace Engineering 2018 (November 1, 2018): 1–21. http://dx.doi.org/10.1155/2018/8672760.

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To improve simulations of the flame and pressure wave propagation process and investigate the combustion characteristics of a wave rotor combustor (WRC), direct relation graphs with error propagation (DRGEP), quasi-steady-state assumption (QSSA), and sensitivity analysis were used to establish a reduced reaction mechanism comprised of 23 species and 55 elementary reactions, based on the LLNL N-Butane mechanism. The reduced reaction mechanism of ethylene was combined with an eddy dissipation concept (EDC) model to simulate the flame propagation characteristics in a simplified WRC channel. The effects of spoilers with different blockage ratios and hot-jets of different species on combustion characteristics of flame propagation and pressure rise in the WRC channel were investigated. When the heated inert air was used as hot-jet, the ignition delay time of WRC would increase, which indicated that the activity of the burned gas from the hot-jet igniter would affect the ignition delay time. The spoiler facilitates the coupling of flame and shock waves to reduce the coupling time and distance. With the blockage ratio of the spoiler increasing, the coupling time and distance would be reduced.

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Chakravarty, Koyel, and D. C. Dalal. "Stability analysis of drug dynamics model: A mathematical approach." International Journal of Biomathematics 12, no. 04 (May 2019): 1950043. http://dx.doi.org/10.1142/s1793524519500438.

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In this paper, a mathematical model of drug release from polymeric matrix and consequent intracellular drug transport is proposed and analyzed. Modeling of drug release is done through solubilization dynamics of drug particles, diffusion of the solubilized drug through the polymeric matrix in addition to reversible dissociation/recrystallization process. The interaction between drug-receptor, drug-plasma proteins along with other intracellular endosomal events is modeled. This leads to a mixed system of partial and ordinary differential equations with associated pertinent set of initial and boundary conditions. Furthermore, besides the stability of the proposed model, several sub-models are also studied for their stability criteria. Prominence is provided to the reduced model system having requisite relevance to the original system where quasi steady state approximation (QSSA) theory is utilized. For the model to be potent enough to generate appropriate predictive results for drug delivery, the stability properties of equilibrium in the mathematical model are analyzed both analytically and numerically. Numerical simulation in the embodiment of graphical representations speaks about various vital characteristics of the underlying physical phenomena along with the importance and sensitized impact of the model parameters controlling significant biological functions. Probed new therapies and clinical procedures could be assessed considering the present mathematical model and its analysis as the basis framework in order to effectively enhance therapeutic efficacy and improved patient compliance. The present study confirms the necessity of stability analysis study so that advocated mathematical model can effectively complement the real physiological behavior of pharmacokinetics.

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Zhang, Fengyuan, and Hamid Emami-Meybodi. "Instability of a Diffusive Boundary Layer beneath a Capillary Transition Zone." Fluids 3, no. 4 (October 31, 2018): 85. http://dx.doi.org/10.3390/fluids3040085.

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Natural convection induced by carbon dioxide (CO2) dissolution from a gas cap into the resident formation brine of a deep saline aquifer in the presence of a capillary transition zone is an important phenomenon that can accelerate the dissolution process, reducing the risk of CO2 leakage to the shallower formations. Majority of past investigations on the instability of the diffusive boundary layer assumed a sharp CO2–brine interface with constant CO2 concentration at the top of the aquifer, i.e., single-phase system. However, this assumption may lead to erroneous estimates of the onset of natural convection. The present study demonstrates the significant effect of the capillary transition zone on the onset of natural convection in a two-phase system in which a buoyant CO2 plume overlaid a water-saturated porous layer. Using the quasi-steady-state approximation (QSSA), we performed a linear stability analysis to assess critical times, critical wavenumbers, and neutral stability curves as a function of Bond number. We show that the capillary transition zone could potentially accelerate the evolution of the natural convection by sixfold. Furthermore, we characterized the instability problem for capillary-dominant, in-transition, and buoyancy-dominant systems. In the capillary-dominant systems, capillary transition zone has a strong role in destabilizing the diffusive boundary layer. In contrast, in the buoyancy-dominant systems, the buoyancy force is the sole cause of the instability, and the effect of the capillary transition zone can be ignored. Our findings provide further insight into the understanding of the natural convection in the two-phase CO2–brine system and the long-term fate of the injected CO2 in deep saline aquifers.

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Li, Banghe, Bo Li, and Yuefeng Shen. "A much better replacement of the Michaelis–Menten equation and its application." International Journal of Biomathematics 12, no. 01 (January 2019): 1950008. http://dx.doi.org/10.1142/s1793524519500086.

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Michaelis–Menten equation is a basic equation of enzyme kinetics and gives acceptable approximations of real chemical reaction processes. Analyzing the derivation of this equation yields the fact that its good performance of approximating real reaction processes is due to Michaelis–Menten curve (8). This curve is derived from Quasi-Steady-State Assumption (QSSA), which has been proved always true and called Quasi-Steady-State Law by Banghe Li et al. [Quasi-steady state laws in enzyme kinetics, J. Phys. Chem. A 112(11) (2008) 2311–2321]. Here, we found a polynomial equation with total degree of four [Formula: see text] (14), which gives more accurate approximation of the reaction process in two aspects: during the quasi-steady-state of the reaction, Michaelis–Menten curve approximates the reaction well, while our equation [Formula: see text] gives better approximation; near the end of the reaction, our equation approaches the end of the reaction with a tangent line the same to that of the reaction process trajectory simulated by mass action, while Michaelis–Menten curve does not. In addition, our equation [Formula: see text] differs to Michaelis–Menten curve less than the order of [Formula: see text] as [Formula: see text] approaches [Formula: see text]. By considering the above merits of [Formula: see text], we suggest it as a replacement of Michaelis–Menten curve. Intuitively, this new equation is more complex and harder to understand. But, just because of its complexity, it provides more information about the rate constants than Michaelis–Menten curve does. Finally, we get a better replacement of the Michaelis–Menten equation by combing [Formula: see text] and the equation [Formula: see text].

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Konishi, Eiji. "Core-halo quasi-stationary states in the Hamiltonian mean-field model." International Journal of Modern Physics B 30, no. 12 (May 6, 2016): 1630007. http://dx.doi.org/10.1142/s0217979216300073.

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A characteristic feature of long-range interacting systems is that they become trapped in a non-equilibrium and long-lived quasi-stationary state (QSS) during the early stages of their development. We present a comprehensive review of recent studies of the core-halo structure of QSSs, in the Hamiltonian mean-field model (HMF), which is a mean-field model of mutually coupled ferromagnetic XY spins located at a point, obtained by starting from various unsteady rectangular water-bag type initial phase-space distributions. The main result exposed in this review is that the core-halo structure can be described by the superposition of two independent Lynden–Bell distributions. We discuss the completeness of collisionless relaxation of this double Lynden–Bell distribution by using both of Lynden–Bell entropy and double Lynden–Bell entropy for the systems at low energies per particle.

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Grace, Richard E., and Thomas J. Templin. "QSS." NASPA Journal 32, no. 1 (October 1, 1994): 74–80. http://dx.doi.org/10.1080/00220973.1994.11072381.

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Sharp, Faith C., and Vanessa Sperandio. "QseA Directly Activates Transcription of LEE1 in Enterohemorrhagic Escherichia coli." Infection and Immunity 75, no. 5 (March 5, 2007): 2432–40. http://dx.doi.org/10.1128/iai.02003-06.

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ABSTRACT Quorum sensing (QS) in enterohemorrhagic Escherichia coli (EHEC) regulates the expression of the locus of enterocyte effacement (LEE). The LEE contains five major operons named LEE1 through LEE5. QseA was previously shown to be activated through QS and to activate the transcription of LEE1. The LEE1 operon encodes Ler, the transcription activator of all other LEE genes, and has two promoters: a distal promoter (P1) and a proximal promoter (P2). We have previously reported that QseA acts on P1 and not P2. To identify the minimal region of LEE1 that is necessary for QseA-mediated activation, a series of nested-deletion constructs of the LEE1 promoter fused to a lacZ reporter were constructed in both the EHEC and E. coli K-12 backgrounds. In an EHEC background, QseA-dependent activation of LEE1 can be observed for the entire regulatory region (beginning at nucleotide −393 and ending at nucleotide −123). In contrast to what occurred in EHEC, in K-12 there was no QseA-dependent activation of LEE1 transcription between base pairs −393 and −343. These data indicate that a QseA-dependent EHEC-specific regulator is required for the activation of transcription in this region. We also observed QseA-dependent LEE1 activation from nucleotides −218 to −123 in K-12, similar to results of the nested-deletion analysis performed with EHEC. Electrophoretic mobility shift assays established that QseA directly binds to the region of LEE1 from bp −173 to −42 and not to the region from bp −393 to −343. These studies suggest that QseA activates the transcription of LEE1 by directly binding upstream of its P1 promoter region.

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Narlikar, Jayant V. "An Alternative Cosmology: The QSSC." Symposium - International Astronomical Union 183 (1999): 277–85. http://dx.doi.org/10.1017/s0074180900132942.

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This review begins with a brief survey of the observational constraints on the standard big bang cosmology, pointing out that the various limits leave a very narrow window in the parameter space of plausible models. There is thus a strong case for alternative cosmologies. The rest of the review concentrates on one alternative, the quasi steady state cosmology (QSSC) and summarises the recent work on this model. This includes, the theoretical formulation and simple exact solutions of the basic equations, their relationship to observations, the stability of solutions and the toy model for understanding the growth of structures in the universe.

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Zhang, Zhiwei, Hongyuan Gao, Jingya Ma, Shihao Wang, and Helin Sun. "Blind Source Separation Based on Quantum Slime Mould Algorithm in Impulse Noise." Mathematical Problems in Engineering 2021 (July 28, 2021): 1–17. http://dx.doi.org/10.1155/2021/1496156.

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In order to resolve engineering problems that the performance of the traditional blind source separation (BSS) methods deteriorates or even becomes invalid when the unknown source signals are interfered by impulse noise with a low signal-to-noise ratio (SNR), a more effective and robust BSS method is proposed. Based on dual-parameter variable tailing (DPVT) transformation function, moving average filtering (MAF), and median filtering (MF), a filtering system that can achieve noise suppression in an impulse noise environment is proposed, noted as MAF-DPVT-MF. A hybrid optimization objective function is designed based on the two independence criteria to achieve more effective and robust BSS. Meanwhile, combining quantum computation theory with slime mould algorithm (SMA), quantum slime mould algorithm (QSMA) is proposed and QSMA is used to solve the hybrid optimization objective function. The proposed method is called BSS based on QSMA (QSMA-BSS). The simulation results show that QSMA-BSS is superior to the traditional methods. Compared with previous BSS methods, QSMA-BSS has a wider applications range, more stable performance, and higher precision.

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Merinero Rodríguez, Rafael. "La agenda de investigación del turismo mediante el Análisis Cuantitativo de Redes Sociales (QSNA)." Cuadernos de Turismo, no. 36 (July 14, 2015): 269. http://dx.doi.org/10.6018/turismo.36.230991.

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El trabajo realiza un recorrido por la literatura aparecida en los últimos años en las revistas científicas y libros que han utilizado el Análisis Cuantitativo de Redes Sociales (QSNA, en inglés) para el estudio del turismo. Se presenta de forma sistemática todas las aportaciones científicas que han usado los métodos y técnicas propias del QSNA para el análisis del turismo, lo que permitirá que cualquier investigador pueda disponer de las referencias oportunas con el objeto de poder orientar sus trabajos de investigación utilizando el QSNA. A partir del análisis de todas estas aportaciones se plantea una propuesta de avance para la futura agenda de investigación del turismo desde el QSNA.

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French, Jacqueline, and Gary Gronseth. "The QSS Responds." Neurology Today 7, no. 9 (May 2007): 3. http://dx.doi.org/10.1097/01.nt.0000280871.87421.63.

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Uroz, Stéphane, Phil M. Oger, Emilie Chapelle, Marie-Thérèse Adeline, Denis Faure, and Yves Dessaux. "A Rhodococcus qsdA-Encoded Enzyme Defines a Novel Class of Large-Spectrum Quorum-Quenching Lactonases." Applied and Environmental Microbiology 74, no. 5 (January 11, 2008): 1357–66. http://dx.doi.org/10.1128/aem.02014-07.

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ABSTRACT A gene involved in N-acyl homoserine lactone (N-AHSL) degradation was identified by screening a genomic library of Rhodococcus erythropolis strain W2. This gene, named qsdA (for quorum-sensing signal degradation), encodes an N-AHSL lactonase unrelated to the two previously characterized N-AHSL-degrading enzymes, i.e., the lactonase AiiA and the amidohydrolase AiiD. QsdA is related to phosphotriesterases and constitutes the reference of a novel class of N-AHSL degradation enzymes. It confers the ability to inactivate N-AHSLs with an acyl chain ranging from C6 to C14, with or without substitution at carbon 3. Screening of a collection of 15 Rhodococcus strains and strains closely related to this genus clearly highlighted the relationship between the ability to degrade N-AHSLs and the presence of the qsdA gene in Rhodococcus. Bacteria harboring the qsdA gene interfere very efficiently with quorum-sensing-regulated functions, demonstrating that qsdA is a valuable tool for developing quorum-quenching procedures.

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Narison, Stephan. "The value of fB from QSSR." Physics Letters B 308, no. 3-4 (July 1993): 365–71. http://dx.doi.org/10.1016/0370-2693(93)91299-3.

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Narison, S. "More comments on ƒB from QSSR." Physics Letters B 285, no. 1-2 (July 1992): 141–44. http://dx.doi.org/10.1016/0370-2693(92)91313-x.

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LI, Jing, Peng XU, Jia-wu ZHOU, Feng-yi HU, Xian-neng DENG, Zhi-wei CHEN, and Da-yun TAO. "Molecular Mapping of Sterility QTLs qSS-3, qSS-6a and qSS-7 as Single Mendelian Factors via NIL strategy." Rice Science 18, no. 2 (June 2011): 110–15. http://dx.doi.org/10.1016/s1672-6308(11)60016-4.

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Chen, Hamilton, and Vincent Reginald Narvaez. "Ultrasound-Guided Quadrilateral Space Block for the Diagnosis of Quadrilateral Syndrome." Case Reports in Orthopedics 2015 (2015): 1–4. http://dx.doi.org/10.1155/2015/378627.

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Quadrilateral space syndrome (QSS) is a rare nerve entrapment disorder that occurs when the axillary nerve and posterior circumflex humeral artery (PCHA) become compressed in the quadrilateral space. QSS presents as vague posterolateral shoulder pain that is exacerbated upon the abduction and external rotation of the shoulder. Diagnosis of QSS is difficult because of the vague presentation of QSS. In addition, even though MRI and MR angiography can be used in QSS diagnosis, there is currently no “gold standard” diagnostic imaging studies for QSS. In this case report, we describe a novel ultrasound-guided technique for a diagnostic quadrilateral space block and present a case where the diagnostic block was used to diagnose QSS. We believe that a diagnostic block of the quadrilateral space is a useful adjunct in the evaluation of patients with suspected QSS, especially in cases where examination findings and other diagnostic modalities are indeterminate.

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Sperandio, Vanessa, Caiyi C. Li, and James B. Kaper. "Quorum-Sensing Escherichia coli Regulator A: a Regulator of the LysR Family Involved in the Regulation of the Locus of Enterocyte Effacement Pathogenicity Island in Enterohemorrhagic E. coli." Infection and Immunity 70, no. 6 (June 2002): 3085–93. http://dx.doi.org/10.1128/iai.70.6.3085-3093.2002.

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ABSTRACT The locus of enterocyte effacement (LEE) is a chromosomal pathogenicity island that encodes the proteins involved in the formation of the attaching and effacing lesions by enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). The LEE comprises 41 open reading frames organized in five major operons, LEE1, LEE2, LEE3, tir (LEE5), and LEE4, which encode a type III secretion system, the intimin adhesin, the translocated intimin receptor (Tir), and other effector proteins. The first gene of LEE1 encodes the Ler regulator, which activates all the other genes within the LEE. We previously reported that the LEE genes were activated by quorum sensing through Ler (V. Sperandio, J. L. Mellies, W. Nguyen, S. Shin, and J. B. Kaper, Proc. Natl. Acad. Sci. USA 96:15196-15201, 1999). In this study we report that a putative regulator in the E. coli genome is itself activated by quorum sensing. This regulator is encoded by open reading frame b3243; belongs to the LysR family of regulators; is present in EHEC, EPEC, and E. coli K-12; and shares homology with the AphB and PtxR regulators of Vibrio cholerae and Pseudomonas aeruginosa, respectively. We confirmed the activation of b3243 by quorum sensing by using transcriptional fusions and renamed this regulator quorum-sensing E. coli regulator A (QseA). We observed that QseA activated transcription of ler and therefore of the other LEE genes. An EHEC qseA mutant had a striking reduction of type III secretion activity, which was complemented when qseA was provided in trans. Similar results were also observed with a qseA mutant of EPEC. The QseA regulator is part of the regulatory cascade that regulates EHEC and EPEC virulence genes by quorum sensing.

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Karsanov, Alan Muharbekovich, Zamira Tatarbekovna Astahova, Tamerlan Kazbekovich Gogichaev, Irma Borisovna Tuaeva, and Oleg Valeryevich Remizov. "The Concept of a Single Territorial Approach to Improving the Quality and Safety of Medical Activities on the Example of the Republic of North Ossetia – Alania." Medical Technologies. Assessment and Choice (Медицинские технологии. Оценка и выбор), no. 2 (36) (July 29, 2019): 35–41. http://dx.doi.org/10.31556/2219-0678.2019.36.2.035-041.

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The concept of a unified territorial approach to improving the quality and safety of medical activities (QSMA) in the Republic of North Ossetia – Alania through the implementation of the «Quality Management and Safety Program of Medical Activities» (Program) and the creation of the «Road Map» is disclosed in present article. The main leitmotif of it is to consistently increase the information-legal, educational-motivational, clinical, control-administrative and organizational components of a systematic approach to improving QSMA in all medical institutions (MI) of the region. The program is designed to create conditions for the formation of a new type of MI in the framework of the implementation of the national «Healthcare» project in the region and the training of specialists – QSMA managers.

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Kherouf, Soumaya, Nabil Bouarra, Amel Bouakkadia, and Djelloul Messadi. "Modeling of linear and nonlinear quantitative structure property relationships of the aqueous solubility of phenol derivatives." Journal of the Serbian Chemical Society 84, no. 6 (2019): 575–90. http://dx.doi.org/10.2298/jsc180820016k.

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Quantitative structure?solubility relationships (QSSR) are considered as a type of Quantitative structure?property relationship (QSPR) study in which aqueous solubility of chemicals are related to chemical structure. In the present work, multiple linear regression (MLR) and artificial neural network (ANN) techniques were used for QSSR studies of the water solubility of 68 phenols (phenol and its derivatives) based on molecular descriptors calculated from the optimized 3D structures. By applying missing value, zero and multicollinearity tests with a cutoff value of 0.95, and a genetic algorithm (GA), the descriptors that resulted in the best fitted models were selected. After descriptor selection, multiple linear regression (MLR) was used to construct a linear QSSR model. The R2 = 91.0 %, LOO Q2 = 89.33 %, s = 0.340 values of the model developed by MLR showed a good predictive capability for log S values of phenol and its derivatives. The results of MLR model were compared with those of the ANN model. the comparison showed that the R2 = 94.99 %, s = 0.245 of ANN were higher and lower, respectively, which illustrated an ANN presents an excellent alternative to develop a QSSR model for the log S values of phenols to MLR.

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42

Araújo, Marina Campos, Daniele Mendonça Ferreira, and Rosangela Alves Pereira. "Reprodutibilidade de questionário semiquantitativo de freqüência alimentar elaborado para adolescentes da Região Metropolitana do Rio de Janeiro, Brasil." Cadernos de Saúde Pública 24, no. 12 (December 2008): 2775–86. http://dx.doi.org/10.1590/s0102-311x2008001200006.

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A reprodutibilidade de questionário semiquantitativo de freqüência alimentar (QSFA) para adolescentes do Rio de Janeiro, Brasil, foi analisada entre 108 adolescentes. O intervalo médio entre as duas aplicações do QSFA foi de vinte dias. A lista de alimentos e as porções de referência do QSFA basearam-se em dados de registros alimentares de 430 adolescentes. Estimaram-se coeficientes de correlação intraclasse para itens alimentares e coeficientes de correlação de Pearson para nutrientes. A concordância da classificação em quartis para nutrientes foi estimada pelo kappa ponderado. O método de Bland-Altman avaliou a concordância para nutrientes. Apresentaram-se dados brutos e ajustados pela energia. Para os itens alimentares, a média dos coeficientes de correlação intraclasse foi 0,54. Para dados ajustados, a concordância para o mesmo quartil e quartis adjacentes variou de 72% a 86%. Segundo o método de Bland-Altman, a concordância média variou de 77% a 104% e foram independentes da magnitude do consumo, exceto para vitamina A. Os coeficientes de correlação de Pearson variaram de 0,40 a 0,61. O QSFA demonstrou confiabilidade aceitável para as estimativas de alimentos e nutrientes de adolescentes da área considerada.

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Russell, Regan M., Faith C. Sharp, David A. Rasko, and Vanessa Sperandio. "QseA and GrlR/GrlA Regulation of the Locus of Enterocyte Effacement Genes in Enterohemorrhagic Escherichia coli." Journal of Bacteriology 189, no. 14 (May 11, 2007): 5387–92. http://dx.doi.org/10.1128/jb.00553-07.

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ABSTRACT Transcription of the locus of enterocyte effacement (LEE) genes in enterohemorrhagic Escherichia coli (EHEC) is regulated by the LEE-encoded Ler and GrlR/GrlA proteins as well as the non-LEE-encoded regulator QseA. This work demonstrates that GrlR/GrlA activate LEE2 transcription in a Ler-independent fashion, whereas transcription of grlRA is activated by QseA in both Ler-dependent and -independent manners.

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Jardak, Mohamed, and Olivier Talagrand. "Ensemble variational assimilation as a probabilistic estimator – Part 2: The fully non-linear case." Nonlinear Processes in Geophysics 25, no. 3 (August 24, 2018): 589–604. http://dx.doi.org/10.5194/npg-25-589-2018.

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Abstract. The method of ensemble variational assimilation (EnsVAR), also known as ensemble of data assimilations (EDA), is implemented in fully non-linear conditions on the Lorenz-96 chaotic 40-parameter model. In the case of strong-constraint assimilation, it requires association with the method of quasi-static variational assimilation (QSVA). It then produces ensembles which possess as much reliability and resolution as in the linear case, and its performance is at least as good as that of ensemble Kalman filter (EnKF) and particle filter (PF). On the other hand, ensembles consisting of solutions that correspond to the absolute minimum of the objective function (as identified from the minimizations without QSVA) are significantly biased. In the case of weak-constraint assimilation, EnsVAR is fully successful without need for QSVA.

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45

Yu, Zhi Xiang, Yan Jun Yan, and Hao Wu. "Quasi-Steady Marching-on in Time Approximation Technique of Numerical Simulation of Wind Pressures on Building." Applied Mechanics and Materials 105-107 (September 2011): 576–82. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.576.

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Abstract. In order to improve the convergence of nonlinear simulation of wind pressure on buildings by turbulence theory pattern, QSMA technique is proposed based on full implicit marching-on in time method in CFX. During marching-on in time, the unit time step and non-convergence tolerance test are employed to approximate the steady state solution in this technique. Comparing with the traditional method, the proposed technique can reduce the restriction for time step and requirement for the target tolerance significantly. It is mathematically proved that the time discretization scheme is stable and the error transfer tends to zero with QSMA technique. Through numerical analysis for flow around Marakami 3D cubic, the research result indicates that solution accuracy and time consumption of QSMA are consistent with traditional steady state method, but the convergence is better.

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46

Lian, Jonathan K. M., and Florence Y. Y. Ling. "The influence of personal characteristics on quantity surveyors’ job satisfaction." Built Environment Project and Asset Management 8, no. 2 (May 14, 2018): 183–93. http://dx.doi.org/10.1108/bepam-12-2017-0117.

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PurposeThe purpose of this paper is to investigate the job satisfaction level of quantity surveyors (QSs); identify the personal characteristics that influence their job satisfaction; and provide recommendations to employers on how to enhance job satisfaction of QSs with different personal characteristics.Design/methodology/approachData were collected via a self-administered questionnaire to QSs in Singapore.FindingsQSs feel that they have significantly high passion for the job, are significantly satisfied with task variety and are treated fairly. However, they are significantly dissatisfied with their workload, hours worked, and lack of work-life balance. QSs in upper management have significantly higher job passion. Those in mid-management are more dissatisfied with their income. QSs who are married/attached, older, and more experienced are significantly more dissatisfied with their workload and hours worked than singles, younger, and less experienced QSs.Research limitations/implicationsSome dimensions of job satisfaction were not measured. Non-personal characteristics such as type of projects handled and type of clients were not investigated.Practical implicationsEmployers should investigate what goes into QSs’ workload, and weed out those that are of low value and unproductive in order to reduce their workload and hours worked, and thereby increase their job satisfaction.Social implicationsThe study contributes to human resource management by identifying the type of QSs who are more likely to be dissatisfied with their jobs.Originality/valueThis study shows that personal differences of QSs affect different dimensions of their job satisfaction. To maximize job satisfaction, employers could choose QSs who have specific characteristics, make changes to the work environment or redesign their jobs.

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WANG, CHUNMING, CHENGSONG ZHU, HUQU ZHAI, and JIANMIN WAN. "Mapping segregation distortion loci and quantitative trait loci for spikelet sterility in rice (Oryza sativa L.)." Genetical Research 86, no. 2 (October 2005): 97–106. http://dx.doi.org/10.1017/s0016672305007779.

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Markers with segregation ratio distortion are commonly observed in data sets used for quantitative trait locus (QTL) mapping. In this study, a multipoint method of maximum likelihood (ML) was newly developed to estimate the positions and effects of the segregation distortion loci (SDLs) in two F2 populations of rice (Oryza sativa L.), i.e. Taichung65/Bhadua (TB; japonica–indica cross) and CPSLO17/W207-2 (CW; japonica–japonica). Of the four parents, W207-2 and Bhadua were found to be spikelet semi-sterile and stably inherited through selfing, and spikelet fertility segregated in the two populations. Therefore, recombination frequencies were recalculated after mapping the SDLs by using the multipoint method, and the molecular linkage maps of the two F2 populations were constructed to detect QTLs underlying spikelet fertility. As a result, five SDLs in the TB population were mapped on chromosomes 1, 3, 8 and 9, respectively. Two major QTLs underlying spikelet fertility, namely qSS-6a and qSS-8a, were detected on chromosomes 6 and 8, respectively. In the CW population, a total of 12 SDLs were detected on all 12 chromosomes except 1, 5, 7 and 11. Three QTLs underlying spikelet sterility, namely qSS-2, qSS-6b and qSS-8b on chromosomes 2, 6 and 8, were determined on the whole genome scale. Interestingly, both qSS-6a and qSS-6b, detected in the two F2 populations respectively, were located on a similar position as the S5 gene on chromosome 6; while qSS-8a and qSS-8b were also simultaneously detected on similar positions of the short arm of chromosome 8 in the two populations, which should be a new sterility gene showing the same type of zygotic selection.

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Grant, D. A., C. Franzini, J. Wild, and A. M. Walker. "Continuous measurement of blood flow in the superior sagittal sinus of the lamb." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 269, no. 2 (August 1, 1995): R274—R279. http://dx.doi.org/10.1152/ajpregu.1995.269.2.r274.

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We assessed the validity of recording blood flow in the superior sagittal sinus (Qss) as a measure of cerebral blood flow (CBF). While anesthetized, 10 lambs were instrumented with a transit-time ultrasonic flow probe around the superior sagittal sinus to measure Qss, electrodes to assess sleep state, catheters to measure cerebral perfusion pressure (Pcp), and an occlusive cuff around the common brachiocephalic artery to vary blood pressure. After 72 h recovery, lambs were studied during spontaneous sleep-wake cycles to establish 1) the normal range of Qss and 2) the response rate of Qss to rapid alterations of Pcp. Subsequently, the lambs were reanesthetized, and the measurement of Qss was calibrated and validated. Qss was linearly related to the arterial inflow of 35% of the brain mass (y = 0.5 x + 1.6, r = 0.93, n = 4). Qss was greater in active sleep (154.1 +/- 45.7 ml.min-1 x 100 g-1, mean +/- SD, n = 5) than in quiet sleep (97.1 +/- 40.8 ml.min-1 x 100 g-1) and quiet wakefulness (107 +/- 44.3 ml.min-1 x 100 g-1, P < 0.05). Qss responded rapidly (within one beat) to spontaneous and to induced transient changes in Pcp. We conclude that recording blood flow in the superior sagittal sinus provides a simple, continuous, and quantitative measure of CBF from a defined area of the brain and is appropriate for studying transient changes in the cerebral circulation.

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Hooi, Doreen S. W., Barrie W. Bycroft, Siri Ram Chhabra, Paul Williams, and David I. Pritchard. "Differential Immune Modulatory Activity of Pseudomonas aeruginosa Quorum-Sensing Signal Molecules." Infection and Immunity 72, no. 11 (November 2004): 6463–70. http://dx.doi.org/10.1128/iai.72.11.6463-6470.2004.

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ABSTRACT Pseudomonas aeruginosa releases a spectrum of well-regulated virulence factors, controlled by intercellular communication (quorum sensing) and mediated through the production of small diffusible quorum-sensing signal molecules (QSSM). We hypothesize that QSSM may in fact serve a dual purpose, also allowing bacterial colonization via their intrinsic immune-modulatory capacity. One class of signal molecule, the N-acylhomoserine lactones, has pleiotropic effects on eukaryotic cells, particularly those involved in host immunity. In the present study, we have determined the comparative effects of two chemically distinct and endobronchially detectable QSSM, N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL) and 2-heptyl-3-hydroxy-4 (1H)-quinolone or the Pseudomonas quinolone signal (PQS), on human leukocytes exposed to a series of stimuli designed to detect differential immunological activity in vitro. 3-Oxo-C12-HSL and PQS displayed differential effects on the release of interleukin-2 (IL-2) when human T cells were activated via the T-cell receptor and CD28 (a costimulatory molecule). 3-Oxo-C12-HSL inhibited cell proliferation and IL-2 release; PQS inhibited cell proliferation without affecting IL-2 release. Both molecules inhibited cell proliferation and the release of IL-2 following mitogen stimulation. Furthermore, in the presence of Escherichia coli lipopolysaccharide, 3-oxo-C12-HSL inhibited tumor necrosis factor alpha release from human monocytes, as reported previously (K. Tateda et al., Infect. Immun. 64:37-43, 1996), whereas PQS did not inhibit in this assay. These data highlight the presence of two differentially active immune modulatory QSSM from P. aeruginosa, which are detectable endobronchially and may be active at the host/pathogen interface during infection with P. aeruginosa, should the bronchial airway lymphoid tissues prove to be accessible to QSSM.

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Bali, Raj. "The quasi-steady-state cosmology in a radiation-dominated phase." Modern Physics Letters A 34, no. 32 (October 10, 2019): 1950262. http://dx.doi.org/10.1142/s0217732319502626.

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Analytical solutions for radiation-dominated phase of Quasi-Steady-State Cosmology (QSSC) in Friedmann–Robertson–Walker models are obtained. We find that matter density is positive in all the cases [Formula: see text]. The nature of Hubble parameter (H) in [Formula: see text] is discussed. The deceleration parameter [Formula: see text] is marginally less than zero indicating accelerating universe. The scale factor [Formula: see text] is graphically shown with time. The model represents oscillating universe between the above-mentioned limits. Because of the bounce in QSSC, the maximum density phase is still matter-dominated. The models represent singularity-free model. We also find that the models have event horizon i.e. no observer beyond the proper distance [Formula: see text] can communicate each other in FRW models for radiation-dominated phase in the frame work of QSSC. The FRW models are special classes of Bianchi type I, V, IX spacetimes with zero, negative and positive curvatures, respectively. Initially i.e. at [Formula: see text], the models represent steady model. We have tried to show how a good fit can be obtained to the observations in the framework of QSSC during radiation-dominated phase. The present model is free from singularity, particle horizon and provides a natural explanation for the flatness problem. Therefore, our model is superior to other models.

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Journal articles on the topic 'QSSA'

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