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Manabu Shiraiwa - One of the best experts on this subject based on the ideXlab platform.
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Timescales of secondary organic aerosols to Reach Equilibrium at various temperatures and relative humidities
Atmospheric Chemistry and Physics, 2019Co-Authors: Manabu ShiraiwaAbstract:Abstract. Secondary organic aerosols (SOA) account for a substantial fraction of air particulate matter, and SOA formation is often modeled assuming rapid establishment of gas–particle Equilibrium. Here, we estimate the characteristic timescale for SOA to achieve gas–particle Equilibrium under a wide range of temperatures and relative humidities using a state-of-the-art kinetic flux model. Equilibration timescales were calculated by varying particle phase state, size, mass loadings, and volatility of organic compounds in open and closed systems. Model simulations suggest that the equilibration timescale for semi-volatile compounds is on the order of seconds or minutes for most conditions in the planetary boundary layer, but it can be longer than 1 h if particles adopt glassy or amorphous solid states with high glass transition temperatures at low relative humidity. In the free troposphere with lower temperatures, it can be longer than hours or days, even at moderate or relatively high relative humidities due to kinetic limitations of bulk diffusion in highly viscous particles. The timescale of partitioning of low-volatile compounds into highly viscous particles is shorter compared to semi-volatile compounds in the closed system, as it is largely determined by condensation sink due to very slow re-evaporation with relatively quick establishment of local Equilibrium between the gas phase and the near-surface bulk. The dependence of equilibration timescales on both volatility and bulk diffusivity provides critical insights into thermodynamic or kinetic treatments of SOA partitioning for accurate predictions of gas- and particle-phase concentrations of semi-volatile compounds in regional and global chemical transport models.
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Timescales of Secondary Organic Aerosols to Reach Equilibrium at Various Temperatures and Relative Humidities
2019Co-Authors: Manabu ShiraiwaAbstract:Abstract. Secondary organic aerosols (SOA) account for a substantial fraction of air particulate matter and SOA formation is often modeled assuming rapid establishment of gas-particle Equilibrium. Here, we estimate the characteristic timescale for SOA to achieve gas−particle Equilibrium under a wide range of temperatures and relative humidities using a state-of-the-art kinetic flux model. Equilibration timescales were calculated by varying particle phase state, size, mass loadings, and volatility of organic compounds. Model simulations suggest that the equilibration timescale for semi-volatile compounds is on the order of seconds or minutes for most conditions in the planetary boundary layer, but it can be longer than one hour if particles adopt glassy or amorphous solid states with high glass transition temperature at low relative humidity. In the free troposphere with lower temperatures it can be longer than hours or days even at moderate or relatively high RH due to kinetic limitations of bulk diffusion in highly viscous particles. The timescale of partitioning of low-volatile compounds is shorter compared to semi-volatile compounds, as it is largely determined by condensation sink due to very slow re-evaporation. These results provide critical insights into thermodynamic or kinetic treatments of SOA partitioning for accurate predictions of gas- and particle-phase concentrations of semi-volatile compounds in regional and global chemical transport models.
Solenn Stoeckel - One of the best experts on this subject based on the ideXlab platform.
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rare sex or out of Reach Equilibrium the dynamics of f is in partially clonal organisms
BMC Genetics, 2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaudhaond, Solenn StoeckelAbstract:Partially clonal organisms are very common in nature, yet the influence of partial asexuality on the temporal dynamics of genetic diversity remains poorly understood. Mathematical models accounting for clonality predict deviations only for extremely rare sex and only towards mean inbreeding coefficient $$ \overline{F_{IS}}<0 $$ . Yet in partially clonal species, both F IS < 0 and F IS > 0 are frequently observed also in populations where there is evidence for a significant amount of sexual reproduction. Here, we studied the joint effects of partial clonality, mutation and genetic drift with a state-and-time discrete Markov chain model to describe the dynamics of F IS over time under increasing rates of clonality. Results of the mathematical model and simulations show that partial clonality slows down the asymptotic convergence to F IS = 0. Thus, although clonality alone does not lead to departures from Hardy-Weinberg expectations once Reached the final Equilibrium state, both negative and positive F IS values can arise transiently even at intermediate rates of clonality. More importantly, such “transient” departures from Hardy Weinberg proportions may last long as clonality tunes up the temporal variation of F IS and reduces its rate of change over time, leading to a hyperbolic increase of the maximal time needed to Reach the final mean $$ \overline{F_{IS,\infty }} $$ value expected at Equilibrium. Our results argue for a dynamical interpretation of F IS in clonal populations. Negative values cannot be interpreted as unequivocal evidence for extremely scarce sex but also as intermediate rates of clonality in finite populations. Complementary observations (e.g. frequency distribution of multiloci genotypes, population history) or time series data may help to discriminate between different possible conclusions on the extent of clonality when mean $$ \overline{F_{IS}} $$ values deviating from zero and/or a large variation of F IS over loci are observed.
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Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms.
BMC genetics, 2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Partially clonal organisms are very common in nature, yet the influence of partial asexuality on the temporal dynamics of genetic diversity remains poorly understood. Mathematical models accounting for clonality predict deviations only for extremely rare sex and only towards mean inbreeding coefficient $$ \overline{F_{IS}}
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Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms.
BMC Genetics, 2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Background - Partially clonal organisms are very common in nature, yet the influence of partial asexuality on the temporal dynamics of genetic diversity remains poorly understood. Mathematical models accounting for clonality predict deviations only for extremely rare sex and only towards mean inbreeding coefficient [Formula: see text]. Yet in partially clonal species, both F IS 0 are frequently observed also in populations where there is evidence for a significant amount of sexual reproduction. Here, we studied the joint effects of partial clonality, mutation and genetic drift with a state-and-time discrete Markov chain model to describe the dynamics of F IS over time under increasing rates of clonality. Results - Results of the mathematical model and simulations show that partial clonality slows down the asymptotic convergence to F IS = 0. Thus, although clonality alone does not lead to departures from Hardy-Weinberg expectations once Reached the final Equilibrium state, both negative and positive F IS values can arise transiently even at intermediate rates of clonality. More importantly, such "transient" departures from Hardy Weinberg proportions may last long as clonality tunes up the temporal variation of F IS and reduces its rate of change over time, leading to a hyperbolic increase of the maximal time needed to Reach the final mean [Formula: see text] value expected at Equilibrium. Conclusion - Our results argue for a dynamical interpretation of F IS in clonal populations. Negative values cannot be interpreted as unequivocal evidence for extremely scarce sex but also as intermediate rates of clonality in finite populations. Complementary observations (e.g. frequency distribution of multiloci genotypes, population history) or time series data may help to discriminate between different possible conclusions on the extent of clonality when mean [Formula: see text] values deviating from zero and/or a large variation of F IS over loci are observed.
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Additional file 2: of Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms
2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Figures and Tables. 2.1. Interpretation of de Finetti diagrams, 2.2 De Finetti landscapes for reproduction, 2.3 De Finetti landscapes for mutation, 2.4 De Finetti landscapes for genetic drift, 2.5: Dynamics of probability of fixation and distributions of F IS through time for large population size, low mutation rate 10−6 at locus with 10 alleles 2.6: Dynamics of probability of fixation and distributions of F IS through time for large population size, high mutation rate 10−3 at locus with 10 alleles 2.7 Example trajectories over time. 2.8 Sampling error of the mean F IS , t , L ¯ $$ \overline{{\mathrm{F}}_{\mathrm{IS},\mathrm{t},\mathrm{L}}} $$ according to number of loci (Markov chain). 2.9 Sampling error of the mean F IS , t , L ¯ $$ \overline{{\mathrm{F}}_{\mathrm{IS},\mathrm{t},\mathrm{L}}} $$ according to number of loci (simulations) Additional tables. 2.1 transition probabilities conditionally to rates of clonality, mutation rates and previous genotypic state. 2.2 Convergence time of genetic drift t N based on Markov chain absorption time. 2.3: Convergence time of genetic drift t N based on simulations. 2.4 Effects of different rates of clonality on the dynamics of F IS . (DOCX 10902 kb)
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Additional file 1: of Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms
2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Mathematical Background. 1.1 Model equations, 1.2 Convergence times – individual parameters, 1.3 Mutation and heterozygosity – multiple alleles, asymmetric mutation rate, 1.4 Genetic drift and heterozygosity – multiple alleles, 1.5 Convergence times – full model, 1.6 General solution and mixing time of Balloux et al. [13] recurrence equations. (DOCX 73 kb)
Xavier Lefebvre - One of the best experts on this subject based on the ideXlab platform.
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hydrogen induced cracking hic testing of low alloy steel in sour environment impact of time of exposure on the extent of damage
Corrosion Science, 2010Co-Authors: Jean Kittel, Veronique Smanio, M Fregonese, Laurence Garnier, Xavier LefebvreAbstract:Abstract Hydrogen induced cracking (HIC) of line pipe steel was investigated through immersion testing and hydrogen permeation measurements. At constant pH and hydrogen sulphide partial pressure ( p H 2 S), the extent of HIC was found to depend on exposure time until a stable level was Reached. The time to Reach this stable value is affected by pH and p H 2 S. Results of permeation experiments confirmed that HIC is linked with the increase of hydrogen concentration in the steel. It is also shown that low severity requires longer exposures to Reach Equilibrium. This must be taken into account for HIC testing in mildly sour environment.
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Hydrogen induced cracking (HIC) testing of low alloy steel in sour environment: Impact of time of exposure on the extent of damage
Corrosion Science, 2010Co-Authors: Jean Kittel, Veronique Smanio, M Fregonese, Laurence Garnier, Xavier LefebvreAbstract:Hydrogen induced cracking (HIC) of line pipe steel was investigated through immersion testing and hydrogen permeation measurements. At constant pH and hydrogen sulphide partial pressure (pH2S), the extent of HIC was found to depend on exposure time until a stable level was Reached. The time to Reach this stable value is affected by pH and pH2S. Results of permeation experiments confirmed that HIC is linked with the increase of hydrogen concentration in the steel. It is also shown that low severity requires longer exposures to Reach Equilibrium. This must be taken into account for HIC testing in mildly sour environment. © 2009 Elsevier Ltd. All rights reserved.
Felipe Tucca - One of the best experts on this subject based on the ideXlab platform.
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Passive samplers of hydrophobic organic chemicals Reach Equilibrium faster in the laboratory than in the field.
Marine pollution bulletin, 2015Co-Authors: Kees Booij, Felipe TuccaAbstract:The use of passive sampling methods for monitoring hydrophobic organic chemicals frequently requires the determination of equilibration times and partition coefficients in the laboratory. These experiments are often carried out by exposing passive samplers in a finite water volume, and errors are easily made when the obtained results are applied to the field, where water volumes are essentially infinite. The effect of water volume on the equilibration rate constant is discussed, using a mechanistic model. Application of this model to two literature reports illustrates that aqueous concentrations in the field may be underestimated by a factor of 10 or more, when the water volume effect is neglected. Finally, it is shown that the concept of "sorption capacity" (sampler mass times partition coefficient) allows for a more intuitive understanding of the passive sampling process in small and large water volumes, which may reduce the risk of laboratory-field extrapolation errors.
Katja Reichel - One of the best experts on this subject based on the ideXlab platform.
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rare sex or out of Reach Equilibrium the dynamics of f is in partially clonal organisms
BMC Genetics, 2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaudhaond, Solenn StoeckelAbstract:Partially clonal organisms are very common in nature, yet the influence of partial asexuality on the temporal dynamics of genetic diversity remains poorly understood. Mathematical models accounting for clonality predict deviations only for extremely rare sex and only towards mean inbreeding coefficient $$ \overline{F_{IS}}<0 $$ . Yet in partially clonal species, both F IS < 0 and F IS > 0 are frequently observed also in populations where there is evidence for a significant amount of sexual reproduction. Here, we studied the joint effects of partial clonality, mutation and genetic drift with a state-and-time discrete Markov chain model to describe the dynamics of F IS over time under increasing rates of clonality. Results of the mathematical model and simulations show that partial clonality slows down the asymptotic convergence to F IS = 0. Thus, although clonality alone does not lead to departures from Hardy-Weinberg expectations once Reached the final Equilibrium state, both negative and positive F IS values can arise transiently even at intermediate rates of clonality. More importantly, such “transient” departures from Hardy Weinberg proportions may last long as clonality tunes up the temporal variation of F IS and reduces its rate of change over time, leading to a hyperbolic increase of the maximal time needed to Reach the final mean $$ \overline{F_{IS,\infty }} $$ value expected at Equilibrium. Our results argue for a dynamical interpretation of F IS in clonal populations. Negative values cannot be interpreted as unequivocal evidence for extremely scarce sex but also as intermediate rates of clonality in finite populations. Complementary observations (e.g. frequency distribution of multiloci genotypes, population history) or time series data may help to discriminate between different possible conclusions on the extent of clonality when mean $$ \overline{F_{IS}} $$ values deviating from zero and/or a large variation of F IS over loci are observed.
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Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms.
BMC genetics, 2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Partially clonal organisms are very common in nature, yet the influence of partial asexuality on the temporal dynamics of genetic diversity remains poorly understood. Mathematical models accounting for clonality predict deviations only for extremely rare sex and only towards mean inbreeding coefficient $$ \overline{F_{IS}}
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Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms.
BMC Genetics, 2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Background - Partially clonal organisms are very common in nature, yet the influence of partial asexuality on the temporal dynamics of genetic diversity remains poorly understood. Mathematical models accounting for clonality predict deviations only for extremely rare sex and only towards mean inbreeding coefficient [Formula: see text]. Yet in partially clonal species, both F IS 0 are frequently observed also in populations where there is evidence for a significant amount of sexual reproduction. Here, we studied the joint effects of partial clonality, mutation and genetic drift with a state-and-time discrete Markov chain model to describe the dynamics of F IS over time under increasing rates of clonality. Results - Results of the mathematical model and simulations show that partial clonality slows down the asymptotic convergence to F IS = 0. Thus, although clonality alone does not lead to departures from Hardy-Weinberg expectations once Reached the final Equilibrium state, both negative and positive F IS values can arise transiently even at intermediate rates of clonality. More importantly, such "transient" departures from Hardy Weinberg proportions may last long as clonality tunes up the temporal variation of F IS and reduces its rate of change over time, leading to a hyperbolic increase of the maximal time needed to Reach the final mean [Formula: see text] value expected at Equilibrium. Conclusion - Our results argue for a dynamical interpretation of F IS in clonal populations. Negative values cannot be interpreted as unequivocal evidence for extremely scarce sex but also as intermediate rates of clonality in finite populations. Complementary observations (e.g. frequency distribution of multiloci genotypes, population history) or time series data may help to discriminate between different possible conclusions on the extent of clonality when mean [Formula: see text] values deviating from zero and/or a large variation of F IS over loci are observed.
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Additional file 2: of Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms
2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Figures and Tables. 2.1. Interpretation of de Finetti diagrams, 2.2 De Finetti landscapes for reproduction, 2.3 De Finetti landscapes for mutation, 2.4 De Finetti landscapes for genetic drift, 2.5: Dynamics of probability of fixation and distributions of F IS through time for large population size, low mutation rate 10−6 at locus with 10 alleles 2.6: Dynamics of probability of fixation and distributions of F IS through time for large population size, high mutation rate 10−3 at locus with 10 alleles 2.7 Example trajectories over time. 2.8 Sampling error of the mean F IS , t , L ¯ $$ \overline{{\mathrm{F}}_{\mathrm{IS},\mathrm{t},\mathrm{L}}} $$ according to number of loci (Markov chain). 2.9 Sampling error of the mean F IS , t , L ¯ $$ \overline{{\mathrm{F}}_{\mathrm{IS},\mathrm{t},\mathrm{L}}} $$ according to number of loci (simulations) Additional tables. 2.1 transition probabilities conditionally to rates of clonality, mutation rates and previous genotypic state. 2.2 Convergence time of genetic drift t N based on Markov chain absorption time. 2.3: Convergence time of genetic drift t N based on simulations. 2.4 Effects of different rates of clonality on the dynamics of F IS . (DOCX 10902 kb)
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Additional file 1: of Rare sex or out of Reach Equilibrium? The dynamics of F IS in partially clonal organisms
2016Co-Authors: Katja Reichel, Jean-pierre Masson, Florent Malrieu, Sophie Arnaud-haond, Solenn StoeckelAbstract:Mathematical Background. 1.1 Model equations, 1.2 Convergence times – individual parameters, 1.3 Mutation and heterozygosity – multiple alleles, asymmetric mutation rate, 1.4 Genetic drift and heterozygosity – multiple alleles, 1.5 Convergence times – full model, 1.6 General solution and mixing time of Balloux et al. [13] recurrence equations. (DOCX 73 kb)
