Simulation of water-bloom in a eutrophic lake—II. Reassessment of buoyancy,gas vacuole and Turgor pressure of Microcystis aeruginosa

The rate of vertical migration (rising or sinking) of Microcystis aeruginosa colonies in water was represented by Stokes' law. The density, p_p of the colony, estimated conversely from observations on vertical migration rate by using Stokes' law, was shown as a function of gas vacuoles' fraction, V_f in algal cells.Referring to the experimental studies by previous workers on factors that the affect the value of V_f, gas vacuoles in the cells were assumed to collapse instantly, V_f decreasing to V_feq once V_f values exceed those of V_feq. The latter values of V_feq were defined from a cumulative and normal distribution of gas vacuoles that withstand the turgor pressure. P, Incidentally, the regeneration rate of gas vacuoles in the cells that were subjected to sonication, yielding V_f = 0 (non-vacuolate) was constant regardless of the post-sonication environment of light and/or dark.Taking for granted that there exist upper and lower limits of turgor pressures for a given algal cell, an equation on the rate of change in turgor presure of the cell was derived. Presentation of these rate equations is a prerequisite for modeling and simulating emergence and/or disappearance of the waterbloom in still waters of eutrophic lakes and/or ponds.     

Investigation of the energetics of methane-utilising bacteria in methane- and oxygen-limited chemostat cultures

A special apparatus was used to establish methane- and oxygen-limited chemostat cultures of a methane-utilising bacterium, at 30 °C, pH = 7.0, respectively. Although total growth yields with respect to methane and oxygen were hardly affected by dissolved oxygen concentration in the medium, provided dilution rate was kept nearly at 0.1 h^?1, these values appeared to increase slightly with the increase of dilution rate. Assuming that no metabolites other than carbon dioxide and water were produced during bacterial growth, maintenance coefficients and true growth yields were assessed from specific rates of methane uptake and respiration. These energetic constants, nearly independent of the limiting substrates, either methane or oxygen, were compared with those from published data on facultative and obligate aerobes, including a mixed culture of methane-utilising bacteria.     

Spatio-temporal cortical source imaging of brain electrical activity by means of time-varying parametric projection filter

In the present study, we explore suitable spatio-temporal filters for inverse estimation of an equivalent dipole-layer distribution from the scalp electroencephalogram (EEG) for imaging of brain electric sources. We propose a time-varying parametric projection filter (tPPF) for the spatio-temporal EEG analysis. The performance of this tPPF algorithm was evaluated by computer simulation studies. An inhomogeneous three-concentric-spheres model was used in the present simulation study to represent the head volume conductor. An equivalent dipole layer was used to represent equivalently brain electric sources and estimated from the scalp potentials. The tPPF filter was tested to remove time-varying noise such as instantaneous artifacts caused by eyes-blink. The present simulation results indicate that the proposed time-variant tPPF method provides enhanced performance in rejecting time-varying noise, as compared with the time-invariant parametric projection filter.     

CAL: A theoretical background of constraint logic programming and its applications

Constraint logic programming (CLP) is an extension of logic programming by introducing the facility of writing and solving constraints in a certain domain. CAL (Contrainte avec Logique) is a CLP language in which (possibly non-linear) polynomial equations can be written as constraints, while almost all the other CLP languages proposed so far have concentrated only on linear equations and inequations. This paper describes a general semantics of CLP including CAL, and shows the validity of CAL in this framework.     

Current status of low-dose CDDP. 5-FU therapy for solid malignant tumors--nationwide questionnaire survey

A nation-wide questionnaire survey was undertaken concerning low-dose anticancer therapy of CDDP plus 5-FU, which involves (5-10 mg CDDP/body/day + 300-500 mg/body/day) for 4-6 weeks. Out of 1,525 cases from 130 institutions, 847 cases with evaluable lesions were collected from 79 institutions. The response rate was 56.4% in esophageal cancer, 34.3% in gastric cancer, 35.3% in colorectal cancer, 47.2% in liver cancer and 35.9% in lung cancer, respectively. Adverse effects were found to be fewer and compliance was much better than the conventional therapy. Such figures suggest that the present regimen may be more effective than any so far. Problems for medical administration such as unlicensed CDDP for colorectal cancer were pointed out, which hinder the forthcoming third phase study.     

Position sensorless starting of super high-speed PM Generator for micro gas turbine

Position sensorless speed control of super high-speed permanent magnet (PM) motor for micro gas turbine generation system is described. Mechanically robust surface PM (SPM) generator is installed in a turbine system. This generator is used as the starting motor. The sensorless control of the synchronous generator/motor is done by using voltage/frequency (V/F) control strategy without current loop. After the simulation of the proposed strategy, no-load starting test of the generator and actual starting test of the gas-turbine system are done. The proposed sensorless-control system can start and control the PM motor from zero to 30 000 r/min. The results show that the proposed system is robust for accelerating the generator even in the existence of the disturbance caused by the ignition of the turbine.