Integrable eight-state supersymmetric U model with boundary terms and its Bethe ansatz solution

A class of integrable boundary terms for the eight-state supersymmetric U model are presented by solving the graded reflection equations. The boundary model is solved by using the coordinate Bethe ansatz method and the Bethe ansatz equations are obtained. (C) 1998 Elsevier Science B.V.

Effects of geological inhomogeneity on high Rayleigh number steady state heat and mass transfer in fluid-saturated porous media heated from below

A parametric study is carried out to investigate how geological inhomogeneity affects the pore-fluid convective flow field, the temperature distribution, and the mass concentration distribution in a fluid-saturated porous medium. The related numerical results have demonstrated that (1) the effects of both medium permeability inhomogeneity and medium thermal conductivity inhomogeneity are significant on the pore-fluid convective flow and the species concentration distribution in the porous medium; (2) the effect of medium thermal conductivity inhomogeneity is dramatic on the temperature distribution in the porous medium, but the effect of medium permeability inhomogeneity on the temperature distribution may be considerable, depending on the Rayleigh number involved in the analysis; (3) if the coupling effect between pore-fluid flow and mass transport is weak, the effect of the Lewis number is negligible on the pore-fluid convective flow and temperature distribution, hut it is significant on the species concentration distribution in the medium.

Eight-state supersymmetric U model of strongly correlated fermions

An integrable eight-state supersymmetric U model is proposed, which is a fermion model with correlated single-particle and pair hoppings as well as uncorrelated triple-particle hopping. It has a gl(3/1) supersymmetry and contains one symmetry-preserving free parameter. The model is solved and the Bethe ansatz equations are obtained. [S0163-1829(98)00616-X].

Quantum-state protection in cavities

We show how an initially prepared quantum state of a radiation mode in a cavity can be preserved for a long time using a feedback scheme based on the injection of appropriately prepared atoms. We present a feedback scheme both for optical cavities, which can be continuously monitored by a photodetector, and for microwave cavities, which can be monitored only indirectly via the detection of atoms that have interacted with the cavity field. We also discuss the possibility of applying these methods for decoherence control in quantum information processing.

Measurement and state preparation via ion trap quantum computing

We investigate in detail the effects of a QND vibrational number measurement made on single ions in a recently proposed measurement scheme for the vibrational state of a register of ions in a linear rf trap [C. D'HELON and G. J. MILBURN, Phys Rev. A 54, 5141 (1996)]. The performance of a measurement shows some interesting patterns which are closely related to searching.

O-2 uptake during solid-state fermentation in a rotating drum bioreactor

The maximum O-2 uptake by Rhizopus oligosporus grown in a 200 litre rotating drum bioreactor at 0.5 rpm ranged from 6.7 to 7.6 mmol per min per kg initial dry substrate (IDS), for runs done with 4 baffles each 17 cm wide, and 12 baffles each 5 cm wide. Without baffles, the maximum O-2 uptake rate at 5 rpm was 6.9 mmol/(min.kg IDS), compared to 5.1 mmol/(min.kg IDS) obtained at 0.5 rpm. Therefore O-2 supply is adequate in rotating drum bioreactors as long as slumping flow regimes of the substrate bed are avoided.

Selection of a strain of Aspergillus for the production of citric acid from pineapple waste in solid-state fermentation

Aspergillus foetidus ACR I 3996 (=FRR 3558) and three strains of Aspergillus niger ACM 4992 (=ATCC 9142), ACM 4993 (=ATCC 10577), ACM 4994 (=ATCC 12846) were compared for the production of citric acid from pineapple peel in solid-state fermentation. A. niger ACM 4992 produced the highest amount of citric acid, with a yield of 19.4 g of citric acid per 100 g of dry fermented pineapple waste under optimum conditions, representing a yield of 0.74 g citric acid/g sugar consumed. Optimal conditions were 65% (w/w) initial moisture content, 3% (v/w) methanol, 30 degrees C, an unadjusted initial pH of 3.4, a particle size of 2 mm and 5 ppm Fe2+. Citric acid production was best in flasks, with lower yields being obtained in tray and rotating drum bioreactors.

Proliferation in monocyte-derived dendritic cell cultures is caused by progenitor cells capable of myeloid differentiation

Dendritic cells (DC) can be generated by culture of adherent peripheral blood (PB) cells in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). There is controversy as to whether these DC arise from proliferating precursors or simply from differentiation of monocytes. DC were generated from myeloid-enriched PB non-T cells or sorted monocytes. DC generated from either population functioned as potent antigen-presenting cells. Uptake of [H-3]-thymidine was observed in DC cultured from myeloid-enriched non-T cells. Addition of lipopolysaccharide or tumor necrosis factor-alpha led to maturation of the DC, but did not inhibit proliferation. Ki67(+) cells were observed in cytospins of these DC, and by double staining were CD3(-)CD19(-)CD11c(-)CD40(-) and myeloperoxidase(+), suggesting that they were myeloid progenitor cells. Analysis of the starting population by flow cytometry demonstrated small numbers of CD34(+)CD33(-)CD14(-) progenitor cells, and numerous granulocyte-macrophage colony-forming units were generated in standard assays. Thus, production of DC in vitro from adherent PB cells also enriches for progenitor cells that are capable of proliferation after exposure to GM-CSF. Of clinical importance, the yield of DC derived in the presence of GM-CSF and IL-4 cannot be expanded beyond the number of starting monocytes. (C) 1998 by The American Society of Hematology.

Nine classes of integrable boundary conditions for the eight-state supersymmetric fermion model

Nine classes of integrable boundary conditions for the eight-state supersymmetric model of strongly correlated fermions are presented. The boundary systems are solved by using the coordinate Bethe ansatz method and the Bethe ansatz equations for all nine cases are given.

Proliferation in monocyte-derived dendritic cell cultures is due to cells capable of myeloid differentiation

Dendritic cells (DC) can be generated by culture of adherent peripheral blood (PB) cells in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). There is controversy as to whether these DC arise from proliferating precursors or simply from differentiation of monocytes. DC were generated from myeloid-enriched PB non-T cells or sorted monocytes. DC generated from either population functioned as potent antigen-presenting cells. Uptake of [H-3]-thymidine was observed in DC cultured from myeloid-enriched non-T cells. Addition of lipopolysaccharide or tumor necrosis factor-alpha led to maturation of the DC, but did not inhibit proliferation. Ki67(+) cells were observed in cytospins of these DC, and by double staining were CD3(-)CD19(-)CD11c(-)CD40(-) and myeloperoxidase(+), suggesting that they were myeloid progenitor cells. Analysis of the starting population by flow cytometry demonstrated small numbers of CD34(+)CD33(-)CD14(-) progenitor cells, and numerous granulocyte-macrophage colony-forming units were generated in standard assays. Thus, production of DC in vitro from adherent PB cells also enriches for progenitor cells that are capable of proliferation after exposure to GM-CSF. Of clinical importance, the yield of DC derived in the presence of GM-CSF and IL-4 cannot be expanded beyond the number of starting monocytes. (C) 1998 by The American Society of Hematology.

A state-contingent production approach to principal-agent problems with an application to point-source pollution control

Two basic representations of principal-agent relationships, the 'state-space' and 'parameterized distribution' formulations, have emerged. Although the state-space formulation appears more natural, analytical studies using this formulation have had limited success. This paper develops a state-space formulation of the moral-hazard problem using a general representation of production under uncertainty. A closed-form solution for the agency-cost problem is derived. Comparative-static results are deduced. Next we solve the principal's problem of selecting the optimal output given the agency-cost function. The analysis is applied to the problem of point-source pollution control. (C) 1998 Published by Elsevier Science S.A. All rights reserved.

Effects of medium thermoelasticity on high Rayleigh number steady-state heat transfer and mineralization in deformable fluid-saturated porous media heated from below

In this paper, a solution method is presented to deal with fully coupled problems between medium deformation, pore-fluid flow and heat transfer in fluid-saturated porous media having supercritical Rayleigh numbers. To validate the present solution method, analytical solutions to a benchmark problem are derived for some special cases. After the solution method is validated, a numerical study is carried out to investigate the effects of medium thermoelasticity on high Rayleigh number steady-state heat transfer and mineralization in fluid-saturated media when they are heated from below. The related numerical results have demonstrated that: (1) medium thermoelasticity has a little influence on the overall pattern of convective pore-fluid flow, but it has a considerable effect on the localization of medium deformation, pore-fluid flow, heat transfer and mineralization in a porous medium, especially when the porous medium is comprised of soft rock masses; (2) convective pore-fluid flow plays a very important role in the localization of medium deformation, heat transfer and mineralization in a porous medium. (C) 1999 Elsevier Science S.A. All rights reserved.

Formal derivation of finite state machines for class testing

Previous work on generating state machines for the purpose of class testing has not been formally based. There has also been work on deriving state machines from formal specifications for testing non-object-oriented software. We build on this work by presenting a method for deriving a state machine for testing purposes from a formal specification of the class under test. We also show how the resulting state machine can be used as the basis for a test suite developed and executed using an existing framework for class testing. To derive the state machine, we identify the states and possible interactions of the operations of the class under test. The Test Template Framework is used to formally derive the states from the Object-Z specification of the class under test. The transitions of the finite state machine are calculated from the derived states and the class's operations. The formally derived finite state machine is transformed to a ClassBench testgraph, which is used as input to the ClassBench framework to test a C++ implementation of the class. The method is illustrated using a simple bounded queue example.