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Papers by Anton kast

Research paper thumbnail of Systèmes et Procédés De Pré-Lecture D'Éléments De Contenu

Research paper thumbnail of Rendu Multimédia Avec Métadonnées D'Orientation

Research paper thumbnail of Augmentation of 5-aminolevulinic Acid Treatment of Glioblastoma by Adding Ciprofloxacin, Deferiprone, 5-fluorouracil and Febuxostat: The CAALA Regimen

The CAALA (Complex Augmentation of ALA) regimen was developed with the goal of redressing some of... more The CAALA (Complex Augmentation of ALA) regimen was developed with the goal of redressing some of the weaknesses of 5-aminolevulinic acid (5-ALA) use in glioblastoma treatment as it now stands. 5-ALA is approved for use prior to glioblastoma surgery to better demarcate tumor from brain tissue. 5-ALA is also used in intraoperative photodynamic treatment of glioblastoma by virtue of uptake of 5-ALA and its selective conversion to protoporphyrin IX in glioblastoma cells. Protoporphyrin IX becomes cytotoxic after exposure to 410 nm or 635 nm light. CAALA uses four currently marketed drugs - the antibiotic ciprofloxacin, the iron chelator deferiprone, the antimetabolite 5-FU, and the xanthine oxidase inhibitor febuxostat - that all have evidence of ability to both increase 5-ALA mediated intraoperative glioblastoma demarcation and photodynamic cytotoxicity of in situ glioblastoma cells. Data from testing the full CAALA on living minipigs xenotransplanted with human glioblastoma cells wil...

Research paper thumbnail of Virtual Underlying Security

Real option theory, that can be used for valuing public investments or solve optimal time schedul... more Real option theory, that can be used for valuing public investments or solve optimal time schedule problems, is based on the existence of a r e l e v ant underlying security. In many applied works, there is no asset connected with obviousness to the risk to value and the diiculty is to determine such a relevant underlying asset. In this paper we propose a method for constructing a virtual underlying security a s a portfolio of marketed assets, based on the functional correlation coeecient. Then, we tackle several problems arising in this replication procedure in an empirical setting. We thank Professor Hans F ollmer for helpful discussion. y CNRS-GREQAM-IDEP, k ast@ehess.cnrs-mrs.fr z GREQAM-IDEP Universit e d'Aix-Marseille, groupe ESCMP, lapied@ehess.cnrs-mrs.fr x GREQAM, pardo@ehess.cnrs-mrs.fr.

Research paper thumbnail of Optimal prediction of stiff oscillatory mechanics

Proceedings of the National Academy of Sciences, 2000

We consider many-body problems in classical mechanics where a wide range of time scales limits wh... more We consider many-body problems in classical mechanics where a wide range of time scales limits what can be computed. We apply the method of optimal prediction to obtain equations that are easier to solve numerically. We demonstrate by examples that optimal prediction can reduce the amount of computation needed to obtain a solution by several orders of magnitude.

Research paper thumbnail of Correlation length and average loop length of the fully packed loop model

Journal of Physics A: Mathematical and General, 1996

The fully-packed loop model of closed paths covering the honeycomb lattice is studied through its... more The fully-packed loop model of closed paths covering the honeycomb lattice is studied through its identification with the sl q (3) integrable lattice model. Some known results from the Bethe ansatz solution of this model are reviewed. The free energy, correlation length, and the ensemble average loop length are given explicitly for the many-loop phase. The results are compared with the known result for the model's surface tension. A perturbative formalism is introduced and used to verify results.

Research paper thumbnail of Prediction of large-scale dynamics using unresolved computations

We present a theoretical framework and numerical methods for predicting the large-scale propertie... more We present a theoretical framework and numerical methods for predicting the large-scale properties of solutions of partial differential equations that are too complex to be properly resolved. We assume that prior statistical information about the distribution of the solutions is available, as is often the case in practice. The quantities we can compute condition the prior information and allow us to calculate mean properties of solutions in the future. We derive approximate ways for computing the evolution of the probabilities conditioned by what we can compute, and obtain ordinary differential equations for the expected values of a set of large-scale variables. Our methods are demonstrated on two simple but instructive examples, where the prior information consists of invariant canonical distributions

Research paper thumbnail of On the prediction of large-scale dynamics using unresolved computations

Contemporary Mathematics, 1999

We present a.. theoretical fra.IIlework and numerical methods for predicting the large-scale prop... more We present a.. theoretical fra.IIlework and numerical methods for predicting the large-scale properties of soiutions of partial differential equations that are too complex to be properly resolved. We assume that prior statistical information about the distribution of the solutions is available, as is often the case in practice. The quantities we can compute condition the prior information and allow us to calculate mean properties of solutions in the future. We derive approximate ways for computing the evolution of the probabilities conditioned by what we can compute, and obtain ordinary differential equations for the expected values of a set of large-scale variables. Our methods are demonstrated on two simple but instructive exa.IIlples, where the prior information consists of invariant canonical distributions 1991 Mathematics Subject Classification. Primary 65M99.

Research paper thumbnail of Optimal prediction of underresolved dynamics

Proceedings of the National Academy of Sciences, 1998

A method is presented for computing the average solution of problems that are too complicated for... more A method is presented for computing the average solution of problems that are too complicated for adequate resolution, but where information about the statistics of the solution is available. The method involves computing average derivatives by interpolation based on linear regression, and an updating of a measure constrained by the available crude information. Examples are given.

Research paper thumbnail of The influence of the flow of the reacting gas on the conditions for a thermal explosion

Proceedings of the National Academy of Sciences, 1997

The classical problem of thermal explosion is modified so that the chemically active gas is not a... more The classical problem of thermal explosion is modified so that the chemically active gas is not at rest but is flowing in a long cylindrical pipe. Up to a certain section the heat-conducting walls of the pipe are held at low temperature so that the reaction rate is small and there is no heat release; at that section the ambient temperature is increased and an exothermic reaction begins. The question is whether a slow reaction regime will be established or a thermal explosion will occur. The mathematical formulation of the problem is presented. It is shown that when the pipe radius is larger than a critical value, the solution of the new problem exists only up to a certain distance along the axis. The critical radius is determined by conditions in a problem with a uniform axial temperature. The loss of existence is interpreted as a thermal explosion; the critical distance is the safe reactor’s length. Both laminar and developed turbulent flow regimes are considered. In a computationa...

Research paper thumbnail of Unresolved computation and optimal predictions

Communications on Pure and Applied Mathematics, 1999

We present methods for predicting the solution of time-dependent partial differential equations w... more We present methods for predicting the solution of time-dependent partial differential equations when that solution is so complex that it cannot be properly resolved numerically, but when prior statistical information can be found. The sparse numerical data are viewed as constraints on the solution, and the gist of our proposal is a set of methods for advancing the constraints in time so that regression methods can be used to reconstruct the mean future. For linear equations we offer general recipes for advancing the constraints; the methods are generalized to certain classes of nonlinear problems, and the conditions under which strongly nonlinear problems and partial statistical information can be handled are briefly discussed. Our methods are related to certain data acquisition schemes in oceanography and meteorology.

Research paper thumbnail of Systèmes et Procédés De Pré-Lecture D'Éléments De Contenu

Research paper thumbnail of Rendu Multimédia Avec Métadonnées D'Orientation

Research paper thumbnail of Augmentation of 5-aminolevulinic Acid Treatment of Glioblastoma by Adding Ciprofloxacin, Deferiprone, 5-fluorouracil and Febuxostat: The CAALA Regimen

The CAALA (Complex Augmentation of ALA) regimen was developed with the goal of redressing some of... more The CAALA (Complex Augmentation of ALA) regimen was developed with the goal of redressing some of the weaknesses of 5-aminolevulinic acid (5-ALA) use in glioblastoma treatment as it now stands. 5-ALA is approved for use prior to glioblastoma surgery to better demarcate tumor from brain tissue. 5-ALA is also used in intraoperative photodynamic treatment of glioblastoma by virtue of uptake of 5-ALA and its selective conversion to protoporphyrin IX in glioblastoma cells. Protoporphyrin IX becomes cytotoxic after exposure to 410 nm or 635 nm light. CAALA uses four currently marketed drugs - the antibiotic ciprofloxacin, the iron chelator deferiprone, the antimetabolite 5-FU, and the xanthine oxidase inhibitor febuxostat - that all have evidence of ability to both increase 5-ALA mediated intraoperative glioblastoma demarcation and photodynamic cytotoxicity of in situ glioblastoma cells. Data from testing the full CAALA on living minipigs xenotransplanted with human glioblastoma cells wil...

Research paper thumbnail of Virtual Underlying Security

Real option theory, that can be used for valuing public investments or solve optimal time schedul... more Real option theory, that can be used for valuing public investments or solve optimal time schedule problems, is based on the existence of a r e l e v ant underlying security. In many applied works, there is no asset connected with obviousness to the risk to value and the diiculty is to determine such a relevant underlying asset. In this paper we propose a method for constructing a virtual underlying security a s a portfolio of marketed assets, based on the functional correlation coeecient. Then, we tackle several problems arising in this replication procedure in an empirical setting. We thank Professor Hans F ollmer for helpful discussion. y CNRS-GREQAM-IDEP, k ast@ehess.cnrs-mrs.fr z GREQAM-IDEP Universit e d'Aix-Marseille, groupe ESCMP, lapied@ehess.cnrs-mrs.fr x GREQAM, pardo@ehess.cnrs-mrs.fr.

Research paper thumbnail of Optimal prediction of stiff oscillatory mechanics

Proceedings of the National Academy of Sciences, 2000

We consider many-body problems in classical mechanics where a wide range of time scales limits wh... more We consider many-body problems in classical mechanics where a wide range of time scales limits what can be computed. We apply the method of optimal prediction to obtain equations that are easier to solve numerically. We demonstrate by examples that optimal prediction can reduce the amount of computation needed to obtain a solution by several orders of magnitude.

Research paper thumbnail of Correlation length and average loop length of the fully packed loop model

Journal of Physics A: Mathematical and General, 1996

The fully-packed loop model of closed paths covering the honeycomb lattice is studied through its... more The fully-packed loop model of closed paths covering the honeycomb lattice is studied through its identification with the sl q (3) integrable lattice model. Some known results from the Bethe ansatz solution of this model are reviewed. The free energy, correlation length, and the ensemble average loop length are given explicitly for the many-loop phase. The results are compared with the known result for the model's surface tension. A perturbative formalism is introduced and used to verify results.

Research paper thumbnail of Prediction of large-scale dynamics using unresolved computations

We present a theoretical framework and numerical methods for predicting the large-scale propertie... more We present a theoretical framework and numerical methods for predicting the large-scale properties of solutions of partial differential equations that are too complex to be properly resolved. We assume that prior statistical information about the distribution of the solutions is available, as is often the case in practice. The quantities we can compute condition the prior information and allow us to calculate mean properties of solutions in the future. We derive approximate ways for computing the evolution of the probabilities conditioned by what we can compute, and obtain ordinary differential equations for the expected values of a set of large-scale variables. Our methods are demonstrated on two simple but instructive examples, where the prior information consists of invariant canonical distributions

Research paper thumbnail of On the prediction of large-scale dynamics using unresolved computations

Contemporary Mathematics, 1999

We present a.. theoretical fra.IIlework and numerical methods for predicting the large-scale prop... more We present a.. theoretical fra.IIlework and numerical methods for predicting the large-scale properties of soiutions of partial differential equations that are too complex to be properly resolved. We assume that prior statistical information about the distribution of the solutions is available, as is often the case in practice. The quantities we can compute condition the prior information and allow us to calculate mean properties of solutions in the future. We derive approximate ways for computing the evolution of the probabilities conditioned by what we can compute, and obtain ordinary differential equations for the expected values of a set of large-scale variables. Our methods are demonstrated on two simple but instructive exa.IIlples, where the prior information consists of invariant canonical distributions 1991 Mathematics Subject Classification. Primary 65M99.

Research paper thumbnail of Optimal prediction of underresolved dynamics

Proceedings of the National Academy of Sciences, 1998

A method is presented for computing the average solution of problems that are too complicated for... more A method is presented for computing the average solution of problems that are too complicated for adequate resolution, but where information about the statistics of the solution is available. The method involves computing average derivatives by interpolation based on linear regression, and an updating of a measure constrained by the available crude information. Examples are given.

Research paper thumbnail of The influence of the flow of the reacting gas on the conditions for a thermal explosion

Proceedings of the National Academy of Sciences, 1997

The classical problem of thermal explosion is modified so that the chemically active gas is not a... more The classical problem of thermal explosion is modified so that the chemically active gas is not at rest but is flowing in a long cylindrical pipe. Up to a certain section the heat-conducting walls of the pipe are held at low temperature so that the reaction rate is small and there is no heat release; at that section the ambient temperature is increased and an exothermic reaction begins. The question is whether a slow reaction regime will be established or a thermal explosion will occur. The mathematical formulation of the problem is presented. It is shown that when the pipe radius is larger than a critical value, the solution of the new problem exists only up to a certain distance along the axis. The critical radius is determined by conditions in a problem with a uniform axial temperature. The loss of existence is interpreted as a thermal explosion; the critical distance is the safe reactor’s length. Both laminar and developed turbulent flow regimes are considered. In a computationa...

Research paper thumbnail of Unresolved computation and optimal predictions

Communications on Pure and Applied Mathematics, 1999

We present methods for predicting the solution of time-dependent partial differential equations w... more We present methods for predicting the solution of time-dependent partial differential equations when that solution is so complex that it cannot be properly resolved numerically, but when prior statistical information can be found. The sparse numerical data are viewed as constraints on the solution, and the gist of our proposal is a set of methods for advancing the constraints in time so that regression methods can be used to reconstruct the mean future. For linear equations we offer general recipes for advancing the constraints; the methods are generalized to certain classes of nonlinear problems, and the conditions under which strongly nonlinear problems and partial statistical information can be handled are briefly discussed. Our methods are related to certain data acquisition schemes in oceanography and meteorology.