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A renormalizable and asymptotically free $\mathrm{O}(N)$ nonlinear $\ensuremath{\sigma}$ model is defined on a $p$-adic field. The effective potential is computed to the leading order in the $\frac{1}{N}$ expansion and it is shown that the mass term for the $\mathrm{O}(N)$ vector field is generated dynamically and the full $\mathrm{O}(N)$ symmetry is realized linearly. Also a discrete scale invariance of the classical action is shown to be violated because of quantum effects.

Cosmological solutions are investigated in Kaluza-Klein models with and without an anti-symmetric tensor field. Thermal and quantum loop effects are taken into account in solving the Einstein equation. It is shown that the Universe, which started in the radiation-dominated era with initial conditions in a certain region, can evolve into a four-dimensional world with compactified extra dimensions in later time.

Using guinea pig hippocampal slice preparations, the effect of temperature on the electrical activity and the protective effect of hypothermia against deprivation of both oxygen and glucose were studied by recording field potentials of pyramidal cell layer (CA 3–4 area) and by measuring the content of adenosine triphosphate (ATP), phosphocreatine (PCr) and lactate of each slice. Cooling the perfusion medium from 37 to 21 °C caused a decrease in the amplitude of field potentials, although the amplitude increased (120%) transiently at around 33 °C. The electrical activity ceased at around 22 °C. When the temperature was raised from 21 to 37 °C, the activity recovered reversibly. However, when the temperature was raised to above 38 °C, the amplitude decreased and disappeared irreversibly at 42 °C. During deprivation, energy consumption (total ∼P used;2 × ΔATP+ ΔPCr+ 1.3 × Δlactate) was suppressed by lowering the tissue temperature and the initial (0–2.5 min deprivation) energy use rate was calculated to be 42.2 at 37°C, 22.8 at 28 °C and 7.0 at 21 °C (∼P m mol/kg protein/min), respectively. From these values, Q10 was estimated to be 2.05. With regard to the protective effect of hypothermia, the critical survival time (period of deprivation of oxygen and glucose for the complete recovery in neural activity and the level of high energy phosphates) was 10 min at 37 °C, 15 min at 28 °C, and 45 min at 21 °C, respectively. These results indicate that moderate hypothermia (28 °C) is not very effective in protecting the brain tissue against deprivation of oxygen and glucose, and that deep hypothermia (21 °C) has a much more potent protective effect against deprivation from the functional and metabolic viewpoint.

The γ-aminobutyric acid (GABA) concentration of pancreatic islets in rats treated with streptozotocin (STZ) and of human insulinoma tissue was studied. Seven hours after the administration of 65 mg/kg body weight of STZ, a distinct increase in serum insulin concentration and at the same time a decrease in blood glucose level were seen. Twenty-four hours after the injection of STZ, however, the level of serum insulin decreased much, whereas that of blood glucose increased considerably. On the other hand, the GABA concentration of the islet was reduced dramatically to about one-tenth the control level after both 7 and 24 h. The histologic investigations of the islets revealed the destruction of B cells but no changes in A and D cells 7 and 24 h after the treatment of STZ. Nerve fibers and nerve endings in the islets were preserved intact all through the study. The GABA and insulin contents of the two cases of human insulinoma were determined. One insulinoma, which was compactly occupied with B cells according to its histologic features, contained a high concentration of GABA. The other tumor, having a rather sparse distribution of B cells in it as compared with the former case, possessed a lower concentration of GABA, but it was still high compared with that of its surrounding tissues. The present observations indicate that a large amount of GABA is available in the B cells of the pancreaticislets.

The laminar distribution of gamma-aminobutyric acid (GABA) in the superior colliculus of the guinea pig was analyzed. The superficial gray layer, especially the upper half, was found to contain the highest amount, 37.4 +/- 1.1 mmol/kg dry. To investigate the role of GABA in the superficial gray layer, the effect of GABA on neurotransmission in the superficial gray layer was studied in superior colliculus slices in a perfusion system. Bath-applied GABA, 100 microM-1 mM, enhanced the amplitude of the postsynaptic field potential (PSP) in the superficial gray layer dose dependently and at concentrations above 1 mM it depressed the PSP dose dependently. A similar response pattern was obtained with muscimol (0.1-10 microM, enhancement; greater than 10 microM, depression). However, (-)-baclofen only inhibited the PSP dose dependently (0.1-1 microM). The excitatory effect of GABA was enhanced at concentrations of nipecotic acid less than 0.5 mM. Bicuculline 1 microM shifted the dose-response curve of GABA to the right and the excitatory effect was also enhanced. These results indicate that GABA has a dual action on neurotransmission in the superficial gray layer: an excitatory effect, possibly mediated by GABAA receptors and an inhibitory effect mediated by both GABAA and GABAB receptors.

The fine distribution of GABA, glutamic acid decarboxylase, and glutamic acid within each layer of the rabbit cerebellar cortex was determined with microanalytical methods. The greatest glutamic acid decarboxylase activity and the highest GABA concentration were found in the Purkinje cell layer. In the distribution of GABA and glutamic acid decarboxylase the peak of glutamic acid decarboxylase activity was more pronounced than that of GABA; the concentration of glutamic acid did not show much variation between each layer.

Quantum cosmology in Kaluza-Klein-type theories is investigated by using the fundamental equation of quantum gravity: the Wheeler-DeWitt equation. The Casimir stress tensor is considered as a prime source of compactification. By imposing the Hartle-Hawking boundary condition, we demonstrate that a fine-tuning of the boundary condition in the quantum regime is necessary, presumably at a moderate level of ${10}^{\mathrm{\ensuremath{-}}3}$, in order to obtain a sufficient inflation of our space.

The effects of excitatory amino acids such as glutamate (Glu) and aspartate (Asp), and their receptor agonists, kainate (Ka), N-methyl-D-aspartate (NMDA), and quisqualate (Quis) on the neuronal activity and the oxygen consumption were investigated using hippocampal slices of the guinea pig. Bath application of these excitants elevated the amplitude of the postsynaptic field potential (PSP) to approximately 120% of the original level at low concentrations, although effective doses varied for the different excitants (Ka greater than NMDA greater than Quis greater than Glu greater than Asp). At concentrations over each effective dose the PSP was diminished and subsequently abolished. The application of Ka (1 x 10(-8) to 1 x 10(-6) M), NMDA (1 x 10(-8) to 1 x 10(-4) M), Quis (1 x 10(-7) to 1 x 10(-4) M), Glu (1 x 10(-5) to 5 x 10(-4) M), and Asp (1 x 10(-5) to 5 x 10(-3) M) enhanced the oxygen consumption dose-dependently, to a maximum of 120-146% of the resting level (8.43 mumol/g protein/min). It was notable that the initial increase in the oxygen consumption was associated with neuronal excitation and the doses of the excitants producing maximal oxygen consumption was in good agreement with those demonstrating disappearance of the PSP, probably because of massive depolarization of the neurones. The increase of the oxygen consumption and the neuronal activity induced by the excitants were specifically inhibited by their antagonists, such as glutamic acid diethylester (GDEE), DL-2-amino-5-phosphonovaleric acid (APV), and Joro spider toxin (JSTX). The present results strongly suggest that the enhancement of oxygen consumption due to the excitatory amino acids and agonists must reflect the neuronal activation induced by them.

A cosmological solution, corresponding to the exponential expansion of the three-space factor with a slow variation of the radius of the extra dimensions, is found in six-dimensional Maxwell-Einstein theory. This solution can be considered to be a model of the inflationary universe in Kaluza-Klein theory, resolving the problem of the large separation of two scales and that of horizon and flatness simultaneously.

It is well known that during generalized seizures induced by antivitamin B6 agents, such as hydrazides, as well as by direct antagonists of pyridoxine, such as desoxypyridoxine, the GABA concentration is reduced in the whole brain2, 23. The same is true in the vicinity of the human epileptic focus z2. However, previous studies have not established if the GABA reduction is the primary cause of the seizure, i.e. whether the decrease in GABA content occurs prior to the onset of the seizure or in the course of the seizure. Comparing the changes taking place during the preictal period of drug induced seizures with those of the ictal period may answer this problem. A thorough study of the preictal alterations necessitates a regional investigation for two reasons. First, the GABA level differs among brain regions 6,16 in this respect the substantia nigra with its high GABA content is very interesting and second, the susceptibility towards seizure discharges differs among brain regions in this respect the hippocampus, one of the most seizure prone regions of the brain 1°,2°, earns special regard. This led us to determine the GABA content in 11 different regions of the rabbit brain during the preictal and ictal period of generalized seizure discharges. For this purpose it is necessary to use a convulsant which induces seizures after a constant latency, so that the moment at which the seizure starts can be predicted. This requirement is fulfilled by the pyridoxine-analog methoxypiridoxine (MP), a convulsant agent described by Purpura and Gonzales-Monteagudo in 195919, which reduces GABA content in cat cortex after systemic application 18. An intravenous administration of 100 mg/kg MP to immobilized rabbits induced generalized seizure discharges starting constantly after 22-28 min as checked by EEG recordings 7. This made it possible to analyze precisely changes occurring during the preictal period. The MP-induced sustained epileptic discharges lasted throughout the experiment for 2 h and longer. To avoid side-effects such as dyspnoea and anoxia, which may also alter the GABA content, all rabbits were artificially respirated and immobili

The effects of glutamate (Glu), kainate (Ka), and N-methyl-D-aspartate (NMDA) on the oxygen consumption of the hippocampal slices of the guinea pig were investigated. The oxygen consumption of slices at resting state was 8.43 mumol/g protein/min. Bath application of Ka (1 x 10(-8) to 1 x 10(-6) M), NMDA (1 x 10(-8) M to 1 x 10(-4) M), and Glu (1 x 10(-5) M to 5 x 10(-4) M) enhanced the oxygen consumption dose-dependently in the similar tendency although the effective doses varied for the different excitants. Subsequently the consumption was maximal at approximately 140% of the resting level. The enhancement of the oxygen consumption due to NMDA and Glu was antagonized by DL-2-amino-5-phosphonovaleric acid (APV) for NMDA and by glutamic acid diethylester (GDEE) and Joro spider toxin (JSTX) for Glu. From these results it was suggested that the increase of the oxygen consumption observed here must reflect the neuronal activation induced by these excitants.

The supercurrent and superconformal anomalies are investigated in N=1 super Yang-Mills theory using the lattice regularization. It is shown that for a wide class of the choice for the action and the supercurrent, the anomaly structure is the same as that in the continuum theory.

The possibility for breakdown of N = 2 supersymmetry (SUSY) is investigated by a 1 n expansion in two-dimensional models with O( n ) symmetries. To the leading order of the 1 n expansion, we find: (i) SUSY is neither broken nor restored in a U( n )-symmetric QED with a vanishing trace of the U(1) charge, (ii) in a U( n )-symmetric QED with a nonvanishing trace of the U(1) charge, SUSY is unbroken irrespective of whether it is broken or not at the tree level, (iii) SUSY is not restored in an O( n )-symmetric O'Raifeartaigh model with broken SUSY at the tree level, (iv) SUSY is not broken in an O( n )-symmetric model with a general superpotential.

Effects of accumulation of phosphocreatine (P-creatine) on utilization and restoration of high-energy phosphates during anoxia and recovery were studied using thin hippocampal slices from the guinea pig. Incubation of slices with creatine (5 to 30 mM) increased the content of tissue P-creatine, in a linear fashion, and these increases depended on the concentration of creatine and the incubation period to as long as 3 h. Concentration of ATP in the slices was not altered. A high concentration of tissue P-creatine (40 to 100 mmol/kg protein) accumulated by incubation with creatine reduced the rate of ATP exhaustion during anoxia whereas P-creatine itself was rapidly decreased. During reoxygenation after anoxia, concentrations of ATP and P-creatine rapidly recovered in slices preincubated with creatine. Concentrations of P-creatine previously exhausted during anoxia increased to 100 mmol/kg protein after 25 min of reoxygenation whereas the concentration was 35 mmol/kg in the control slice. Elevation of the concentration of P-creatine may therefore prolong the survival time of brain tissue during anoxia and facilitate recovery during reoxygenation.

Thyristor-controlled shaft generator is one of fuel/maintenance cost saving methods applied to recent advanced vessels. In this paper, Emergency Take Home mode by motoring operation of the generator installed on 80, 000DWT Oil/Bulk/Ore carrier is described. Test result under sea trial was satisfactory.

High concentration of phosphocreatine (P-creatine) was accumulated in the hippocampal slices incubated in the medium containing creatine. Electrophysiological study revealed that the accumulation of P-creatine in the slice not only prolonged the latency of the loss of the postsynaptic potential (PSP) during anoxia (deprivation of oxygen and glucose), but also enhanced the tolerance to the deprivation resulting in the complete recovery of the PSP. Biochemical study revealed that the P-creatine accumulation not only slowed down the rate of decrease of ATP during anoxia but facilitated the recovery of the high-energy phosphates during recovery. Thus the accumulation of P-creatine in the slices prolonged the survival time of the brain tissue during deprivation of O 2 and glucose

Catalytic hydrogenation of 2-naphthol (NL) with the six platinum metals has been studied in t-BuOH at 80 °C and 4–5 MPa H2 pressure. Selectivities for formation of 1,2,3,- and 5,6,7,8-tetrahydro-2-naphthols (ac- and ar-TLs) have been determined by application of a kinetic equation. ar-TL was formed more predominantly than ac-TL over all the metals. The hydrogenation of ac- and ar-TLs has also been studied under the same conditions for comparison. The hydrogenation of NL and ar-TL was accompanied by extensive hydrogenolysis to give decalins over Os, Ir, and Pt, whereas the hydrogenolysis occurred only slightly over Ru, Rh, and Pd. In general the hydrogenolysis occurred to much lesser extents with ac-TL. The amounts of 2-decalone formed in hydrogenation of ar-TL have been determined by application of the kinetic equation. The 2-decalone was the cis isomer only except with Pd. For formation of the cis products at the ring juncture, hydrogenation of ar-TL was highly stereoselective with Ru, Rh, Os, and Ir, wh...

Twenty days after complete uni- or bilateral hippocampus extirpation in rats, a 25% decrease in glutamate concentration was observed in the septum. Glutamate content also decreased in other terminal structures of the hippocampo-subicular system, i.e. entorhinal cortex, nucleus accumbens septi, mammillary bodies and contralateral hippocampus. It is concluded that the fall in glutamate content which is absent in caudate nucleus is specific for target regions of the hippocampal efferents, adding further support to the suggested transmitter role of glutamate in the limbic system.

Using a σ -model approach to the p adic string in the presence of tachyonic background fields, we compute the s -function corresponding to a discrete scale invariance. It is shown, up to second order in tachyon fields, that the requirement of vanishing s -function reproduces the tachyonic field equation previously derived from the analysis of p -adic tree amplitudes.

We describe the calculation of a {beta} function for the {ital p}-adic string {sigma} model in a tachyonic background, and show that the vanishing condition of the {beta} function reproduces the tachyonic field equation obtained from {ital p}-adic amplitude calculations, up to the fifth order in the tachyonic field. By examining this {sigma} model in the presence of a soliton background, we show that a previously obtained soliton solution of the all-order tachyonic field equation follows from the requirement of discrete scale invariance.

A general framework is given for evaluating the contributions of as yet undiscovered heavy quarks to the gluonic decay rate of the Weinberg-Salam type Higgs boson. Since the Yukawa coupling of the Higgs boson to a quark pair is proportional to the quark mass, loop graphs involving heavy quarks have a non-vanishing effect on the gluonic decay width of the Higgs boson. This effect of heavy quarks with massesM j(j=t,...) much greater than the Higgs boson massm H is calculated in an effective gauge theory. The effects of two different kinds of large logarithms, lnM 2 /μ m 2 /μ 2 are separated and summed up by the renormalization group method. It is found that the higher order QCD corrections are large and that the gluonic contribution to the hadronic decay width is significant if there are more than three generations. The Higgs decay width can therefore be used to probe the number of generations of heavy quarks.