Abstract: A fluctuating oscillator includes: an adder that has an input terminal to which an input signal including a main signal and an uncorrelated signal that is uncorrelated with the main signal and is higher in frequency than the main signal is input, and adds a feedback signal to the input signal; a threshold discrimination unit that generates a pulse signal by comparing an addition signal added by the adder with a threshold; a transient response unit that generates an output signal by transiently responding the generated pulse signal; and a feedback loop that feeds back the output signal to the adder as the feedback signal.

Abstract: A fluctuating oscillator includes: an adder that has an input terminal to which an input signal including a main signal and an uncorrelated signal that is uncorrelated with the main signal and is higher in frequency than the main signal is input, and adds a feedback signal to the input signal; a threshold discrimination unit that generates a pulse signal by comparing an addition signal added by the adder with a threshold; a transient response unit that generates an output signal by transiently responding the generated pulse signal; and a feedback loop that feeds back the output signal to the adder as the feedback signal.

Abstract: A fluctuating oscillator includes: a processor including a digital circuit, and the processor includes a random variable generation unit that generates a random variable, a lookup table that stores a waveform signal in advance, a computation unit that imparts fluctuation to the waveform signal based on the waveform signal read from the lookup table, the random variable generated by the random variable generation unit, and a pulse signal to be fed back, a threshold discrimination unit that generates a pulse signal by comparing a fluctuating signal output from the computation unit with a predetermined threshold, and a feedback loop that causes the pulse signal to be fed back to the computation unit.

Abstract: An adder adds a noise signal, an input signal, and a feedback signal. A threshold determination unit compares an addition signal output from the adder with a predetermined threshold, and outputs an ignition pulse signal. A transient response unit causes transient response of the ignition pulse signal, and generates an output signal. An intensity adjustment unit is formed of a variable resistor provided on a feedback loop, adjusts intensity of the feedback signal, and inputs the feedback signal to the adder.

Abstract: An adder adds a noise signal, an input signal, and a feedback signal. A threshold determination unit compares an addition signal output from the adder with a predetermined threshold, and outputs an ignition pulse signal. A transient response unit causes transient response of the ignition pulse signal, and generates an output signal. An intensity adjustment unit is formed of a variable resistor provided on a feedback loop, adjusts intensity of the feedback signal, and inputs the feedback signal to the adder.

Abstract: Four stochastic resonators 20-1 to 20-4 outputting a pulse signal in accordance with a stochastic resonance phenomenon are unidirectionally coupled in a ring-like form to constitute a fluctuation oscillator 10. When a signal output from each of the stochastic resonators 20-1 to 20-4 is successively transmitted in the stochastic resonators 20-1 to 20-4 coupled in a ring-like form, the output timings at each stochastic resonator 20 are synchronized with each other due to a cooperation phenomenon between the stochastic resonators 20-1 to 20-4, so that each stochastic resonator 20 is self-excited to oscillate at a constant period of time.

Abstract: Four stochastic resonators 20-1 to 20-4 outputting a pulse signal in accordance with a stochastic resonance phenomenon are unidirectionally coupled in a ring-like form to constitute a fluctuation oscillator 10. When a signal output from each of the stochastic resonators 20-1 to 20-4 is successively transmitted in the stochastic resonators 20-1 to 20-4 coupled in a ring-like form, the output timings at each stochastic resonator 20 are synchronized with each other due to a cooperation phenomenon between the stochastic resonators 20-1 to 20-4, so that each stochastic resonator 20 is self-excited to oscillate at a constant period of time.

Abstract: &agr;-Hydroxy-&ggr;-carboxymuconic acid-&egr;-semialdehyde dehydrogenase, a gene encoding the enzyme, a recombinant vector containing the gene and a transformant carrying the gene, and processes for producing the enzyme and 2-pyrone-dicarboxylic acid by using the transformant. Use of the transformant can produce &agr;-hydroxy-&ggr;-carboxymuconic acid-&egr;-semialdehyde dehydrogenase in a large amount, thereby permitting industrial production of 2-pyrone-4,6-dicarboxylic acid.

Abstract: &agr;-Hydroxy-&ggr;-carboxymuconic acid-&egr;-semialdehyde dehydrogenase, a gene encoding the enzyme, a recombinant vector containing the gene and a transformant carrying the gene, and processes for producing the enzyme and 2-pyrone-dicarboxylic acid by using the transformant.

Abstract: Microorganisms producing 5-aminolevulinic acid which show a 5-aminolevulinic acid synthetase activity of 2 to 7 (nmol/min/mg protein) under aerobic culture conditions with a dissolved oxygen concentration of 0.70 to 6.60 ppm; a process for producing 5-aminolevulinic acid characterized by culturing one or more microorganisms and harvesting 5-aminolevulinic acid from the obtained culture; a process for producing 5-aminolevulinic acid characterized by culturing 5-aminolevulinic acid-producing microorganisms in a medium containing 5 to 500 &mgr;M of iron components; and a method for culturing 5-aminolevulinic acid-producing microorganisms.

Abstract: &agr;-Hydroxy-&ggr;-carboxymuconic acid-&egr;-semialdehyde dehydrogenase, a gene encoding the enzyme, a recombinant vector containing the gene and a transformant carrying the gene, and processes for producing the enzyme and 2-pyrone-dicarboxylic acid by using the transformant. Use of the transformant can produce &agr;-hydroxy-&ggr;-carboxymuconic acid-&egr;-semialdehyde dehydrogenase in a large amount, thereby permitting industrial production of 2-pyrone-4,6-dicarboxylic acid.

Abstract: A polyamide having repeating units represented by formula (1), wherein R1 represents a divalent hydrocarbon residue optionally having in the structure a heteroatom having no active hydrogen. The polyamide has a high refractive index, is biodegradable, and is useful as a material for fibers and plastics.

Abstract: A polyester having repeating units represented by formula (1): wherein R1 represents a divalent hydrocarbon residue which in its structure may contain a heteroatom having no active hydrogen. The polyester has a high refractive index and biodegradability, and is useful as a material for fibers and plastics.

Abstract: A microorganism that produces 5-aminolevulinic acid, wherein the microorganism has a 5-aminolevulinic acid dehydratase variant having a reduced inhibitor constant for a 5-aminolevulinic acid dehydratase inhibitor. A microorganism that produces 5-aminolevulinic acid, wherein the microorganism is a photosynthetic bacterium that produces 5-aminolevulinic acid without light irradiation. A process for producing 5-aminolevulinic acid comprising the step of culturing a microorganism that produces 5-aminolevulinic acid in a culture medium under at least one condition selected from the group consisting of (a) less than 1 ppm of dissolved oxygen concentration in the culture medium, (b) from -180 to 50 mV of oxidation-reduction potential in the culture medium, and (c from 5.times.10.sup.-9 to (KrM-2.times.10.sup.-8) (mol of O.sub.2 /ml.multidot.min.cndot.cell) of cellular respiration rate, wherein KrM represents the maximum cellular respiration rate when oxygen is supplied in an excess quantity.

Abstract: A microorganism that produces 5-aminolevulinic acid, wherein the microorganism has a 5-aminolevulinic acid dehydratase variant having a reduced inhibitor constant for a 5-aminolevulinic acid dehydratate inhibitor. A microorganism that produces 5-aminolevulinic acid, wherein the microorganism is a photosynthetic bacterium that produces 5-aminolevulinic acid without light irradiation. A progess for producing 5-aminolevulinic acid comprising the step of culturing a microorganism that produces 5-aminolevulinic acid in a culture medium under at least one condition selected from the group consisting of (a) less than 1 ppm of dissolved oxygen concentration in the culture medium, (b) from -180 to 50 mV of oxidation-reduction potential in the culture medium, and (c) from 5.times.10.sup.-9 to (KrM-2.times.10.sup.-8) (mol of O.sub.2 /ml.multidot.min.multidot.cell) of cellular respiration rate, wherein KrM represents the maximum cellular respiration rate when oxygen is supplied in an excess quantity.

Abstract: A method for improving plant salt-tolerance is described, which comprises treating a plant with an active ingredient comprising at least one compound selected from the group consisting of 5-aminolevulinic acid, a derivative of 5-aminolevulinic acid, a salt of 5-aminolevulinic acid, a salt of derivatives of 5-aminolevulinic acid, and hemins. Furthermore, a salt-tolerant plant is described, wherein the plant is treated with the above-described active ingredient. Moreover, a method for causing recovery of a salt-damaged plant is described, comprising administering the above-described active ingredient to a salt-damaged plant.

Abstract: Methods for reducing nitrate nitrogen and oxalic acid contents in plants, each of which comprises applying 5-aminolevulinic acid, a salt thereof or a mixture thereof. Nitrate nitrogen and oxalic acid contents in plants having high nitrate nitrogen and oxalic acid contents can be reduced effectively and easily.

Abstract: A method for improving pigmentation of the rind of anthocyanin-containing apples comprising treating fruit-bearing apple trees or apples before or after harvesting with an effective amount of an agent which comprises 5-aminolevulinic acid, a salt thereof or a mixture thereof as an active component.

Abstract: A method for treating plants with a plant growth promoter comprising 5-aminolevulinic acid or a salt thereof as an active ingredient. This treatment method is effective in enhancing the photosynthetic activity of a plant, enhancing its ability to absorb CO.sub.2, suppressing its respiration, increasing its chlorophyll content and promoting its growth. As a result, the treatment greatly contributes to the promotion of rooting, the reduction of lodging, an increase in yield, an improvement in cold resistance, maintenance of freshness, an improvement and maintenance of green color, the growth of good seedlings, the promotion of organs, an increase in tillers, a shortening of the time required for growth, a relief of chemical damage and an increase in the rooting ratio in, for example, cutting.