The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
D N Basu - One of the best experts on this subject based on the ideXlab platform.
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Lambda hyperonic effect on the normal driplines
Journal of Physics G: Nuclear and Particle Physics, 2008Co-Authors: Chhanda Samanta, P. Roy Chowdhury, D N BasuAbstract:A Generalized Mass formula is used to calculate the neutron and proton drip lines of normal and lambda hypernuclei treating non-strange and strange nuclei on the same footing. Calculations suggest existence of several bound hypernuclei whose normal cores are unbound. Addition of Lambda or, Lambda-Lambda hyperon(s) to a normal nucleus is found to cause shifts of the neutron and proton driplines from their conventional limits.
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Generalized Mass formula for non strange and hypernuclei with su 6 symmetry breaking
Journal of Physics G, 2006Co-Authors: Chhanda Samanta, Roy P Chowdhury, D N BasuAbstract:A simultaneous description of non-strange nuclei and hypernuclei is provided by a single Mass formula inspired by the spin–flavour SU(6) symmetry breaking. This formula is used to estimate the hyperon binding energies of lambda, double lambda, sigma, cascade and theta hypernuclei. The results are found to be in good agreement with the available experimental data on 'bound' nuclei and relativistic as well as quark mean-field calculations. This Mass formula is useful to estimate binding energies over a wide range of Masses including the light Mass nuclei. It is not applicable to a repulsive potential.
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Generalized Mass formula for non-strange and hyper nuclei with SU(6) symmetry breaking
Journal of Physics G: Nuclear and Particle Physics, 2006Co-Authors: Chhanda Samanta, P. Roy Chowdhury, D N BasuAbstract:A simultaneous description of non-strange nuclei and hypernuclei is provided by a single Mass formula inspired by the spin-flavour SU(6) symmetry breaking. This formula is used to estimate the hyperon binding energies of Lambda, double Lambda, Sigma, Cascade and Theta hypernuclei. The results are found to be in good agreement with the available experimental data on 'bound' nuclei and relativistic as well as quark mean field calculations. This Mass formula is useful to estimate binding energies over a wide range of Masses including the light Mass nuclei. It is not applicable for repulsive potential.
Chhanda Samanta - One of the best experts on this subject based on the ideXlab platform.
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Generalized Mass formula for non-strange, strange and multiply-strange nuclear systems
Journal of Physics G, 2010Co-Authors: Chhanda SamantaAbstract:A simultaneous description of non-strange nuclei, hypernuclei and multiply-strange nuclear systems is provided by a single Mass formula which is shown to be useful for estimating binding energies of nuclear systems over a wide Mass range, including the light Mass nuclei. It not only provides a good fit to the existing experimental data on hyperon-separation energies but also reproduces results of the relativistic mean field (RMF) calculations. In addition, it can provide the lambda (Λ), cascade-0 (Ξ0) and cascade-minus (Ξ−) drip lines. The existence of a range of bound pure-hyperonic systems without any neutron and proton is suggested among which 6Λ, 9Ξ0Ξ0, 10Ξ−Ξ−, 1Λ7Ξ0, 1Λ8Ξ−, 1Ξ09Ξ−, 1Ξ−8Ξ0 and 2Λ + 3Ξ0 + 3Ξ− represent the lightest species. In agreement with the RMF predictions, this Generalized Mass formula also predicts the nucleus to be bound. An exotic nucleus is also found to be bound. This new Mass formula can be used in astrophysics for strange stellar objects, as well as in high energy physics for estimating the strangeness production yield in nucleus–nucleus or nucleon–nucleon collisions.
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Lambda hyperonic effect on the normal driplines
Journal of Physics G: Nuclear and Particle Physics, 2008Co-Authors: Chhanda Samanta, P. Roy Chowdhury, D N BasuAbstract:A Generalized Mass formula is used to calculate the neutron and proton drip lines of normal and lambda hypernuclei treating non-strange and strange nuclei on the same footing. Calculations suggest existence of several bound hypernuclei whose normal cores are unbound. Addition of Lambda or, Lambda-Lambda hyperon(s) to a normal nucleus is found to cause shifts of the neutron and proton driplines from their conventional limits.
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Generalized Mass formula for non strange and hypernuclei with su 6 symmetry breaking
Journal of Physics G, 2006Co-Authors: Chhanda Samanta, Roy P Chowdhury, D N BasuAbstract:A simultaneous description of non-strange nuclei and hypernuclei is provided by a single Mass formula inspired by the spin–flavour SU(6) symmetry breaking. This formula is used to estimate the hyperon binding energies of lambda, double lambda, sigma, cascade and theta hypernuclei. The results are found to be in good agreement with the available experimental data on 'bound' nuclei and relativistic as well as quark mean-field calculations. This Mass formula is useful to estimate binding energies over a wide range of Masses including the light Mass nuclei. It is not applicable to a repulsive potential.
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Generalized Mass formula for non-strange and hyper nuclei with SU(6) symmetry breaking
Journal of Physics G: Nuclear and Particle Physics, 2006Co-Authors: Chhanda Samanta, P. Roy Chowdhury, D N BasuAbstract:A simultaneous description of non-strange nuclei and hypernuclei is provided by a single Mass formula inspired by the spin-flavour SU(6) symmetry breaking. This formula is used to estimate the hyperon binding energies of Lambda, double Lambda, Sigma, Cascade and Theta hypernuclei. The results are found to be in good agreement with the available experimental data on 'bound' nuclei and relativistic as well as quark mean field calculations. This Mass formula is useful to estimate binding energies over a wide range of Masses including the light Mass nuclei. It is not applicable for repulsive potential.
Georg Regensburger - One of the best experts on this subject based on the ideXlab platform.
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Complex-balanced equilibria of Generalized Mass-action systems: Necessary conditions for linear stability
Mathematical biosciences and engineering : MBE, 2019Co-Authors: Balázs Boros, Stefan Müller, Georg RegensburgerAbstract:It is well known that, for Mass-action systems, complex-balanced equilibria are asymptotically stable. For Generalized Mass-action systems, even if there exists a unique complex-balanced equilibrium (in every stoichiometric class and for all rate constants), it need not be stable. We first discuss several notions of matrix stability (on a linear subspace) such as D-stability and diagonal stability, and then we apply abstract results on matrix stability to complex-balanced equilibria of Generalized Mass-action systems. In particular, we show that linear stability (on the stoichiometric subspace and for all rate constants) implies uniqueness. For cyclic networks, we characterize linear stability (in terms of D-stability of the Jacobian matrix); and for weakly reversible networks, we give necessary conditions for linear stability (in terms of D-semistability of the Jacobian matrices of all cycles in the network). Moreover, we show that, for classical Mass-action systems, complex-balanced equilibria are not just asymptotically stable, but even diagonally stable (and hence linearly stable). Finally, we recall and extend characterizations of D-stability and diagonal stability for matrices of dimension up to three, and we illustrate our results by examples of irreversible cycles (of dimension up to three) and of reversible chains and S-systems (of arbitrary dimension).
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The Center Problem for the Lotka Reactions with Generalized Mass-Action Kinetics.
Qualitative theory of dynamical systems, 2017Co-Authors: Balázs Boros, Josef Hofbauer, Stefan Müller, Georg RegensburgerAbstract:Chemical reaction networks with Generalized Mass-action kinetics lead to power-law dynamical systems. As a simple example, we consider the Lotka reactions and the resulting planar ODE. We characterize the parameters (positive coefficients and real exponents) for which the unique positive equilibrium is a center.
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Generalized Mass action systems and positive solutions of polynomial equations with real and symbolic exponents invited talk
Computer Algebra in Scientific Computing, 2014Co-Authors: Stefan Müller, Georg RegensburgerAbstract:Dynamical systems arising from chemical reaction networks with Mass action kinetics are the subject of chemical reaction network theory (CRNT). In particular, this theory provides statements about uniqueness, existence, and stability of positive steady states for all rate constants and initial conditions. In terms of the corresponding polynomial equations, the results guarantee uniqueness and existence of positive solutions for all positive parameters.
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Generalized Mass-Action Systems and Positive Solutions of Polynomial Equations with Real and Symbolic Exponents.
arXiv: Dynamical Systems, 2014Co-Authors: Stefan Müller, Georg RegensburgerAbstract:Dynamical systems arising from chemical reaction networks with Mass action kinetics are the subject of chemical reaction network theory (CRNT). In particular, this theory provides statements about uniqueness, existence, and stability of positive steady states for all rate constants and initial conditions. In terms of the corresponding polynomial equations, the results guarantee uniqueness and existence of positive solutions for all positive parameters. We address a recent extension of CRNT, called Generalized Mass-action systems, where reaction rates are allowed to be power-laws in the concentrations. In particular, the (real) kinetic orders can differ from the (integer) stoichiometric coefficients. As with Mass-action kinetics, complex balancing equilibria are determined by the graph Laplacian of the underlying network and can be characterized by binomial equations and parametrized by monomials. In algebraic terms, we focus on a constructive characterization of positive solutions of polynomial equations with real and symbolic exponents. Uniqueness and existence for all rate constants and initial conditions additionally depend on sign vectors of the stoichiometric and kinetic-order subspaces. This leads to a generalization of Birch's theorem, which is robust with respect to certain perturbations in the exponents. In this context, we discuss the occurrence of multiple complex balancing equilibria. We illustrate our results by a running example and provide a MAPLE worksheet with implementations of all algorithmic methods.
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Generalized Mass action systems and positive solutions of polynomial systems with parameters
2014Co-Authors: Georg RegensburgerAbstract:Chemical reaction network theory provides statements about uniqueness, existence, and stability of positive steady states of the related dynamical systems for all rate constants. The relevant conditions depend only on the network structure and the stoichiometric subspace. In terms of polynomial equations, they guarantee existence and uniqueness of positive solutions for all parameters. We discuss an extension of several statements to Generalized Mass action systems where reaction rates are allowed to be power-laws in the concentrations. In this setting, uniqueness and existence additionally depend on sign vectors of the stoichiometric and kinetic-order subspaces. This is joint work with Stefan Muller.
Stefan Müller - One of the best experts on this subject based on the ideXlab platform.
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Complex-balanced equilibria of Generalized Mass-action systems: Necessary conditions for linear stability
Mathematical biosciences and engineering : MBE, 2019Co-Authors: Balázs Boros, Stefan Müller, Georg RegensburgerAbstract:It is well known that, for Mass-action systems, complex-balanced equilibria are asymptotically stable. For Generalized Mass-action systems, even if there exists a unique complex-balanced equilibrium (in every stoichiometric class and for all rate constants), it need not be stable. We first discuss several notions of matrix stability (on a linear subspace) such as D-stability and diagonal stability, and then we apply abstract results on matrix stability to complex-balanced equilibria of Generalized Mass-action systems. In particular, we show that linear stability (on the stoichiometric subspace and for all rate constants) implies uniqueness. For cyclic networks, we characterize linear stability (in terms of D-stability of the Jacobian matrix); and for weakly reversible networks, we give necessary conditions for linear stability (in terms of D-semistability of the Jacobian matrices of all cycles in the network). Moreover, we show that, for classical Mass-action systems, complex-balanced equilibria are not just asymptotically stable, but even diagonally stable (and hence linearly stable). Finally, we recall and extend characterizations of D-stability and diagonal stability for matrices of dimension up to three, and we illustrate our results by examples of irreversible cycles (of dimension up to three) and of reversible chains and S-systems (of arbitrary dimension).
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A generalization of Birchs theorem and vertex-balanced steady states for Generalized Mass-action systems.
Mathematical biosciences and engineering : MBE, 2019Co-Authors: Gheorghe Craciun, Stefan Müller, Casian PanteaAbstract:Mass-action kinetics and its generalizations appear in mathematical models of (bio)chemical reaction networks, population dynamics, and epidemiology. The dynamical systems arising from directed graphs are generally non-linear and difficult to analyze. One approach to studying them is to find conditions on the network which either imply or preclude certain dynamical properties. For example, a vertex-balanced steady state for a Generalized Mass-action system is a state where the net flux through every vertex of the graph is zero. In particular, such steady states admit a monomial parametrization. The problem of existence and uniqueness of vertex-balanced steady states can be reformulated in two different ways, one of which is related to Birch's theorem in statistics, and the other one to the bijectivity of Generalized polynomial maps, similar to maps appearing in geometric modelling. We present a generalization of Birch's theorem, by providing a sufficient condition for the existence and uniqueness of vertex-balanced steady states.
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A Deficiency-Based Approach to Parametrizing Positive Equilibria of Biochemical Reaction Systems
Bulletin of Mathematical Biology, 2019Co-Authors: Matthew D. Johnston, Stefan Müller, Casian PanteaAbstract:We present conditions which guarantee a parametrization of the set of positive equilibria of a Generalized Mass-action system. Our main results state that (1) if the underlying Generalized chemical reaction network has an effective deficiency of zero, then the set of positive equilibria coincides with the parametrized set of complex-balanced equilibria and (2) if the network is weakly reversible and has a kinetic deficiency of zero, then the equilibrium set is nonempty and has a positive, typically rational, parametrization. Via the method of network translation, we apply our results to classical Mass-action systems studied in the biochemical literature, including the EnvZ–OmpR and shuttled WNT signaling pathways. A parametrization of the set of positive equilibria of a (Generalized) Mass-action system is often a prerequisite for the study of multistationarity and allows an easy check for the occurrence of absolute concentration robustness, as we demonstrate for the EnvZ–OmpR pathway.
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A generalization of Birch's theorem and vertex-balanced steady states for Generalized Mass-action systems
arXiv: Dynamical Systems, 2018Co-Authors: Gheorghe Craciun, Stefan Müller, Casian PanteaAbstract:Mass-action kinetics and its generalizations show up very often in mathematical models of chemical reaction networks, biochemical systems, and population interactions. Vertex-balanced steady states may contain information about the dynamical properties of these systems and have useful algebraic properties. The problem of existence and uniqueness of vertex-balanced steady states can be reformulated in two different ways, one of which is related to the Birch's theorem in statistics, and the other to the bijectivity of Generalized polynomial maps, similar to ones which appear in geometric modelling. We describe a generalization of Birch's theorem that provides a sufficient condition for the existence and uniqueness of vertex-balanced steady states for Generalized Mass-action systems.
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On Global Stability of the Lotka Reactions with Generalized Mass-Action Kinetics
Acta Applicandae Mathematicae, 2017Co-Authors: Balázs Boros, Josef Hofbauer, Stefan MüllerAbstract:Chemical reaction networks with Generalized Mass-action kinetics lead to power-law dynamical systems. As a simple example, we consider the Lotka reactions with two chemical species and arbitrary power-law kinetics. We study existence, uniqueness, and stability of the positive equilibrium, in particular, we characterize its global asymptotic stability in terms of the kinetic orders.
P. Roy Chowdhury - One of the best experts on this subject based on the ideXlab platform.
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Lambda hyperonic effect on the normal driplines
Journal of Physics G: Nuclear and Particle Physics, 2008Co-Authors: Chhanda Samanta, P. Roy Chowdhury, D N BasuAbstract:A Generalized Mass formula is used to calculate the neutron and proton drip lines of normal and lambda hypernuclei treating non-strange and strange nuclei on the same footing. Calculations suggest existence of several bound hypernuclei whose normal cores are unbound. Addition of Lambda or, Lambda-Lambda hyperon(s) to a normal nucleus is found to cause shifts of the neutron and proton driplines from their conventional limits.
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Generalized Mass formula for non-strange and hyper nuclei with SU(6) symmetry breaking
Journal of Physics G: Nuclear and Particle Physics, 2006Co-Authors: Chhanda Samanta, P. Roy Chowdhury, D N BasuAbstract:A simultaneous description of non-strange nuclei and hypernuclei is provided by a single Mass formula inspired by the spin-flavour SU(6) symmetry breaking. This formula is used to estimate the hyperon binding energies of Lambda, double Lambda, Sigma, Cascade and Theta hypernuclei. The results are found to be in good agreement with the available experimental data on 'bound' nuclei and relativistic as well as quark mean field calculations. This Mass formula is useful to estimate binding energies over a wide range of Masses including the light Mass nuclei. It is not applicable for repulsive potential.