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Animals’ sensory systems adjust their responsiveness to environmental stimuli that vary greatly in their intensity. Here we report the neural mechanism of experience-dependent sensory adjustment, especially gain control, in the ASH nociceptive neurons in Caenorhabditis elegans. Using calcium imaging under gradual changes in stimulus intensity, we find that the ASH neurons of naive animals respond to concentration increases in a repulsive odor 2-nonanone regardless of the magnitude of the concentration increase. However, after preexposure to the odor, the ASH neurons exhibit significantly weak responses to a small gradual increase in odor concentration while their responses to a large gradual increase remain strong. Thus, preexposure changes the slope of stimulus–response relationships (i.e., gain control). Behavioral analysis suggests that this gain control contributes to the preexposure-dependent enhancement of odor avoidance behavior. Mathematical analysis reveals that the ASH response consists of fast and slow components, and that the fast component is specifically suppressed by preexposure. In addition, genetic analysis suggests that G protein signaling is required for the fast component. Thus, our integrative study demonstrates how prior experience dynamically modulates stimulus–response relationships in sensory neurons, eventually leading to adaptive modulation of behavior.

A comparative analysis of animal behavior (e.g., male vs. female groups) has been widely used to elucidate behavior specific to one group since pre-Darwinian times. However, big data generated by new sensing technologies, e.g., GPS, makes it difficult for them to contrast group differences manually. This study introduces DeepHL, a deep learning-assisted platform for the comparative analysis of animal movement data, i.e., trajectories. This software uses a deep neural network based on an attention mechanism to automatically detect segments in trajectories that are characteristic of one group. It then highlights these segments in visualized trajectories, enabling biologists to focus on these segments, and helps them reveal the underlying meaning of the highlighted segments to facilitate formulating new hypotheses. We tested the platform on a variety of trajectories of worms, insects, mice, bears, and seabirds across a scale from millimeters to hundreds of kilometers, revealing new movement features of these animals., Comparative analysis of animal behaviour using locomotion data such as GPS data is difficult because the large amount of data makes it difficult to contrast group differences. Here the authors apply deep learning to detect and highlight trajectories characteristic of a group across scales of millimetres to hundreds of kilometres.

Abnormal DNA methylation is involved in the initiation and progression of lymphoid tumors. Hence, DNA demethylating agents are promising candidate drugs for chemotherapy against these tumors. The salicylic acid derived anti-inflammatory agent, olsalazine, reportedly suppresses DNA methyltransferase in human cells and has the potential to be clinically applied as a DNA demethylating agent. In this study, we investigated the effects of olsalazine on cell proliferation and DNA methylation using canine lymphoid tumor cell lines (CLBL-1, GL-1, and UL-1). Treatment with olsalazine led to significant cell growth inhibition and increased the apoptotic rate in all three cell lines. Treatment with olsalazine reduced the total amount of 5-methylcytosine in genomic DNA, as assessed by enzyme-linked immunosorbent assay. Genome-wide analysis of DNA methylation revealed that 1,801 to 5,626 CpG sites showed decreased DNA methylation levels in three cell lines, including the promoter regions of ADAM23, FES, and CREB3L1 genes. The outcomes of the present study demonstrate that a DNA demethylating agent olsalazine, inhibits cell proliferation and DNA methylation in canine lymphoid tumor cells, suggesting that it can be a candidate drug for the treatment of lymphoid tumors in dogs.

Recent advances in robotics and measurement technologies have enabled biologists to record the trajectories created by animal movements. In this paper, we convert time series of animal traj...

Inflammatory colorectal polyps (ICRPs) are characterized by the formation of multiple or solitary polyps with marked neutrophil infiltration in the colorectal area, and are speculated to be a novel form of breed-specific canine idiopathic inflammatory bowel disease (IBD). In human IBD, toll-like receptor (TLR) 2 and TLR4 have been reported to be involved in the pathogenesis of the disease. The aim of this study was to evaluate the expression of TLR2 and TLR4 mRNA in the colorectal mucosa of dogs with ICRPs by in-situ hybridization using an RNAscope assay. Samples of inflamed colorectal mucosa (n = 5) and non-inflamed mucosa (n = 5) from miniature dachshunds (MDs) with ICRPs and colonic mucosa from healthy beagles (n = 5) were examined. TLR2 and TLR4 hybridization signals were localized to the colorectal epithelium, inflammatory cells and fibroblasts in the inflamed colorectal mucosa of affected dogs. The signals were significantly greater in inflamed colorectal epithelium compared with non-inflamed epithelium of MDs with ICRPs and healthy beagles (P

Development of a laser Compton scattering (LCS) gamma-ray source in the UVSOR-III storage ring has been proposed to perform basic research on non-destructive three dimensional isotope imaging. As the first step of the development, a numerical simulation was performed to evaluate the performance of the gamma-ray source. The expected total flux is about 1×107 photons/s when a 1.94-μm CW fiber laser with the maximum power of 5 W collides with 300-mA electron beam circulating in the storage ring. The maximum gamma-ray energy and the total flux available were measured in experiment and determined as 5403 ± 16 keV with 1×10[7] photons/s, respectively. The electron beam energy was evaluated as 746 ± 1 MeV from the measured maximum gamma-ray energy. From the numerical calculation and the experimental result, the energy spread of 2.9% in full width at half maximum and the flux of 4×10[5] photons/s are expected for the LCS gamma-ray beam when a collimator with 2-mm hole is used to limit the scattered angle. The quality of gamma-ray beam generated in UVSOR-III is enough to perform a basic study on the non-destructive three dimensional isotope imaging., CoE on Sustainable Energy System (Thai-Japan), Faculty of Engineering, Rajamangala University of Technology Thanyaburi (RMUTT), Thailand

Recent advancement of bio-logging devices such as GPS sensor enables researchers in ecology to quantitatively measure animal trajectories. These animal trajectory data are often represented in the form of multi-dimensional time-series. In this paper, we develop a method for extracting interesting animal behaviors from these multi-dimensional time-series. To this end, we represent a multi-dimensional time-series as a discrete symbol sequence, and introduce some techniques developed in the context of sequential pattern mining, which has been actively studied in the literature of knowledge discovery and data mining. In animal behavior studies, it is often desired to conduct comparative studies for finding different animal behaviors in different groups, e.g, different behaviors between male and female animals etc. We use a sequential pattern mining method designed for finding so-called discriminative sequential patterns, i.e., sequential patterns that are useful for discriminating different group of animals. We apply the method to several animal trajectory datasets for demonstrating its effectiveness.

Animal behavior is the final and integrated output of the brain activity. Thus, recording and analyzing behavior is critical to understand the underlying brain function. While recording animal behavior has become easier than ever with the development of compact and inexpensive devices, detailed behavioral data analysis requires sufficient previous knowledge and/or high content data such as video images of animal postures, which makes it difficult for most of the animal behavioral data to be efficiently analyzed to understand brain function. Here, we report a versatile method using a hybrid supervised/unsupervised machine learning approach to efficiently estimate behavioral states and to extract important behavioral features only from low-content animal trajectory data. As proof of principle experiments, we analyzed trajectory data of worms, fruit flies, rats, and bats in the laboratories, and penguins and flying seabirds in the wild, which were recorded with various methods and span a wide range of spatiotemporal scales—from mm to 1000 km in space and from sub-seconds to days in time. We estimated several states during behavior and comprehensively extracted characteristic features from a behavioral state and/or a specific experimental condition. Physiological and genetic experiments in worms revealed that the extracted behavioral features reflected specific neural or gene activities. Thus, our method provides a versatile and unbiased way to extract behavioral features from simple trajectory data to understand brain function.

Brains regulate behavioral responses with distinct timings. Here we investigate the cellular and molecular mechanisms underlying the timing of decision-making during olfactory navigation in Caenorhabditis elegans. We find that, based on subtle changes in odor concentrations, the animals appear to choose the appropriate migratory direction from multiple trials as a form of behavioral decision-making. Through optophysiological, mathematical and genetic analyses of neural activity under virtual odor gradients, we further find that odor concentration information is temporally integrated for a decision by a gradual increase in intracellular calcium concentration ([Ca2+]i), which occurs via L-type voltage-gated calcium channels in a pair of olfactory neurons. In contrast, for a reflex-like behavioral response, [Ca2+]i rapidly increases via multiple types of calcium channels in a pair of nociceptive neurons. Thus, the timing of neuronal responses is determined by cell type-dependent involvement of calcium channels, which may serve as a cellular basis for decision-making. DOI: http://dx.doi.org/10.7554/eLife.21629.001, eLife digest Animals use information from their environment to make decisions, like where to go, what to eat, and with whom to mate. This information may be changing or confusing, and decisions may be quick when the sensory information is clear, or slower when the sensory clues are muddled. Scientists often study this kind of decision-making in monkeys and rodents, but it can be hard to pinpoint the exact decision-making mechanisms because these animals have hundreds of millions neurons in their brains. Studying the mechanisms that underlie decision-making can be easier in a simpler organism with fewer neurons. A tiny roundworm called Caenorhabditis elegans is one such creature, with only 302 neurons. These worms avoid noxious odors, by first wandering around when they detect the odor, and then fleeing. About 80% of the time the worms flee in the correct direction to escape the foul smell. However, it was not clear how the worms decided which direction to flee. Now, Tanimoto, Yamazoe-Umemoto et al. show that the worms choose which direction to move by mathematically calculating information about odor concentrations. In the experiments, a robotic microscope simultaneously measured nerve activity and the worm’s behavior while an odor was presented. Specifically, the amount of calcium in the neurons was measured. The experiments showed that when the worms were wandering to determine which direction to flee the amount of calcium in the neurons changed in proportion to how much the concentration of the odor changed overtime. The experiments suggest that the animals use a mathematical process called integration to add up the changes in the concentration of the odor over time, and when the total reaches a certain threshold the animal successfully moves away from the source. Tanimoto, Yamazoe-Umemoto et al. also identified the gene that enables these calculations. More complicated animals make similar calculations that take into account environmental changes over time when making a decision. Future experiments are needed to determine if more complex animals also use the same mechanism as C. elegans, and whether the same gene is responsible. DOI: http://dx.doi.org/10.7554/eLife.21629.002

In this study, we designed and manufactured a pulsed multipole magnet for beam injection into the UVSOR-III ring. A sextupole-like magnetic field could be excited when using the multipole magnet. To compensate for the residual field at the center of the magnet caused by manufacturing imprecisions, thin ferrite sheets were used. The injection experiments at UVSOR-III demonstrated multi-turn injections with the pulsed multipole magnet. The injection efficiency was 23% and the electron beam was stored up to the normal operation current of 300 mA. Moreover, we confirmed that oscillations of stored beams caused by beam injection were drastically suppressed compared with conventional pulsed dipole injection.

Computed Tomography (CT) using X-ray attenuation by atomic effects is now widely used for medical diagnosis and industrial non-destructive inspection. In this study, we performed a tomographic imaging of isotope (208Pb) distribution by the Nuclear Resonance Fluorescence (NRF), i.e. isotope specific resonant absorption and scattering of gamma rays, using Laser Compton Scattering (LCS) gamma rays. The NRF-CT image which includes both effects of atomic attenuation and nuclear resonant attenuation was obtained. By accounting for the atomic attenuation measured by a conventional method at the same time, a clear 208Pb isotope CT image was obtained. The contrast degradation due to notch refilling caused by small-angle Compton scattering is discussed. This study clearly demonstrates the capability of the isotope-specific CT imaging based on nuclear resonant attenuation which will be a realistic technique when the next generation of extremely intense LCS gamma-ray sources will be available. The expected image acquisition time using these intense LCS gamma rays was discussed.

The partial shading effect on the photosynthetic apparatus of the sunflower (Helianthus annuus L.) was examined by monitoring oxygen evolution, maximum quantum yield of PSII photochemistry in dark-adapted leaves (Fv/Fm), the chlorophyll (Chl) concentrations and the Rubisco contents, and leaf mass per area (LMA) at the leaf level and by determining the concentrations of cytochrome (Cyt) f and the reaction centres of photosystem (PS) I and PSII at the thylakoid level. In this experiment, partial shading was defined as the shading of 2nd leaves with shade cloths, and the whole treatment was defined as the covering of the whole individuals with shade cloths. In the leaf level responses, oxygen evolution, LMA, Chl concentrations and Rubisco contents decreased in all shade treatments administered for six days. Fv/Fm remained constant irrespective of the shade treatments. On the other hand, in the thylakoid-level responses, the concentrations of the thylakoid components per unit Chl and the stoichiometry of the two photosystems showed no statistical difference among the shade treatments. The data obtained from the present study indicate that the partial shading affected the leaf-level responses rather than the thylakoid-level responses. The light received at the lower leaves might serve as a factor in the regulation of the leaf properties of the upper leaves due to the whole plant photosynthesis, while this factor did not have an effect at the thylakoid level.

The image quality of high-definition television (HDTV) cameras and camcorders for space activity is degraded by the presence of permanent bright pixels (so-called “white defects”) due to space radiation. We studied the space radiation damage to HDTV charge-coupled devices (CCDs; 2 × 106 pixels per chip) loaded in the Russian service module (SM) of the International Space Station (ISS) for 71 days, 256 days and 446 days. We used the “Passive Dosimeter for Lifescience Experiments in Space” (PADLES), which consists of CR-39 plastic nuclear track detectors (PNTDs) and thermoluminescent dosimeters, to measure space radiation doses received by the HDTV CCDs in the SM during loading periods. The average production rates of white defects for output voltage greater than 0.5 mV were 2.366 ± 0.055 pixels/day in Si and 5.213 ± 0.071 pixels/mGy in Si. We also investigated the correlation between the position of the white defects and tracks of high-energy particles with LET∞,Si of approximately 300 keV/μm or more using stacks of CR-39 PNTDs and the HDTV CCD chips. We found that approximately 30% of these high-energy high-LET particles coincided with the position of white defects on the HDTV CCDs in the SM.

By using a wild-type rice (Oryza sativa L. cv. Norin No. 8) and the chlorophyll (Chl) b-deficient mutant derived from Norin No. 8 (chlorina 11), the present study monitored the oxygen evolution, contents of Chl a and b, β-carotene, and lutein in leaf and the contents of cytochrome f, and the reaction centres of photosystem I (PSI) and photosystem II (PSII) in thylakoids. The oxygen evolution, maximal quantum yield of PSII (Fv/Fm) and Chl concentration remained constant in both Norin No. 8 and chlorina 11 under 5 and 2% of full sunlight for six days. On the other hand, on the thylakoid level, the PSII reaction centre of chlorina 11 was more stable even under high irradiance, while approximately 40% decrease in levels of the PSII reaction centre occurred under 2% of full sunlight for six days. However, under such conditions, by regulating the stoichiometry of active PSII and PSI centres, the light absorption balance in both rice types was adjusted between the two photosystems. The present study attempted to examine whether the light absorption balance between PSII and PSI is altered to effectively conduct photosynthesis in the wild-type and Chl b-deficient mutant rice seedlings.

We present a method of converting moving pictures captured by a single high-definition television camera mounted on the Japanese lunar orbiter Kaguya (Selenological and Engineering Explorer, SELENE) into stereoscopic images. As objects in the moving pictures look as if they are moving vertically, vertical disparity is caused by the time offset of the sequence. The vertical disparity is converted into horizontal disparity by rotating the images by 90 degs. We developed models of the capture and display systems, and geometrically and numerically derived convergence points of observers' eyes. We confirmed that observers could perceive a stereoscopic effect with binocular parallax for the lunar surface at distances of several hundreds of kilometers.

Evergreen fir Abies mariesii growing at the tree line (near 2 500 m altitude) on Mt. Norikura (36°61'N, 137°33'E, 3 026 m altitude) in Central Japan is exposed to harsh winter stresses. To protect against these stresses, the deep-oxidation state of the xanthophyll cycle pigments increased, because the needles contained large amounts of zeaxanthin, which resulted in an increase of non-radiative thermal dissipation from the antenna system. Not only the antenna system but also the inactivated photosystem (PS) 2 reaction centre (RC) might contribute to the heat dissipation of absorbed excess photon energy. In addition, a decrease in the PS2 activity during winter was derived from the degradation of the PS2 RCs. Thus the needles acclimated to the strong sunlight during the harsh winter. Under such conditions, only the abaxial side of A. mariesii needles occasionally changed colour from green to reddish-brown in early spring. Since this needle damage was only observed in shoots that protruded from the snow surface, this phenomenon might be caused by the interaction between the strong sunlight reflected from the snow surface and the long period of sub-zero temperatures. We also examined how the photoprotective functions of A. mariesii growing at the tree line of a temperate zone mitigate the interactive stresses of high photon flux density and sub-zero temperature in harsh winter.

We have recently installed an infrared (IR)–terahertz (THz) beam line BL6B at UVSOR-II. The beam line collects a large acceptance angle of 215(H) × 80(V) mrad2 to obtain high flux in the IR and THz regions. A “magic mirror” with vertical angle focusing was employed as the first mirror. The mirror chamber was directly connected to the bending magnet chamber for collecting the high flux and high brilliance IR and THz light. The obtained performance and the outline of the end stations are reported.

A conceptual design for a test accelerator based on an energy recovery scheme is under way in developing a next generation light source at KEK. A high bright electron beam will be delivered from the test accelerator with a maximum energy of 200 MeV using 1.3 GHz superconducting accelerating cavities installed in two cryomodules. It is of great importance to design a pre-injector that can generate an electron beam with exceptionally high brightness and low emittances. A new simulation code is being developed to simulate the beam dynamics of the electron beam and to optimize the beam characteristics at the pre-injector. The simulation code describes semi-analytically the two-dimensional (transverse and longitudinal) beam dynamics of the electron beam based on a well-known envelope equation taking into account the space charge effect. The purpose of this code is not to rigorously simulate the particle dynamics, as is done by the particle tracking code “Parmela”, but rather to quickly optimize the design parameters of the accelerator components and beam characteristics themselves. This code has been validated by comparison with the results obtained from the “Parmela” code using the pre-injector design parameters. In this report, the development and some numerical results obtained from this new simulation code are presented in detail.

An HDTV high-speed camera that uses three 2.2-M pixel Complementary Metal Oxide Semiconductor (CMOS) image devices has been developed. The camera enables image acquisition up to a maximum speed of 300 frames/sec and stores the image sequences directly in a semi-conductor memory in the camera head. Slow-motion playback is available with a high picture quality because the image sequence is stored without compression. The compact, lightweight, handheld camera can be controlled from a CCU (Camera Control Unit) with a single standard HDTV hybrid fiber-optic camera cable.

The UVSOR electron storage ring has been shutdown since April till August 2003 for upgradation of its performance. This upgrade includes high brightness lattice, longer straight sections for in-vacuum undulators and high-quality vacuum system, and it can increase the brightness of synchrotron radiation from undulators with reduced beam emittance. The improved quality of the electron beam is also of great advantage to the storage ring FEL. To further improve the performance of the FEL and deliver shorter wavelength laser to the user, we are considering a project, which can upgrade the FEL system. One of the solutions is to construct a new in-vacuum optical klystron type undulator in the new long straight section, which is optimized for lasing in the deep UV and VUV region.

Q-switching operation of the storage ring FEL provides high peak power and is therefore very attractive to application experiments. On the UVSOR, the Q-switching is performed by modulation of an RF frequency. Collective synchrotron oscillation of the electron bunch is excited in the actual operation. However, it is found that damping time of the oscillation is 100 times faster than the one expected from synchrotron radiation, so the influence of the collective oscillation on the lasing is relatively small. Analysis reveals that the phenomenon is explained with Robinson damping.

We report a nuclear magnetic/quadrupole resonance study of phase transitions in Cd 2 Re 2 O 7 , specifically the structural transition at ∼200 K and the superconducting one at ∼1 K. Single crystal 111 Cd NMR spectra infer a second-order structural transition at ∼200 K. Splitting of the Cd NMR lines below 200 K, as well as asymmetric electric field gradient obtained from 185/187 Re NQR spectra, point to lack of the three-fold symmetry around [111] direction for these sites. No magnetic order has been found at low temperature. Below 1 K, the zero-field (NQR) spin–lattice relaxation rate of 187 Re exhibits a large coherence peak and behaves within the weak-coupling BCS model with a nearly isotropic energy gap.

Storage ring free-electron lasers (SRFELs) likely have a potentiality for scientific application as a unique light source because of the good coherence and temporal feature in addition to variable wavelength. At the UVSOR, the performance of the SRFEL has been improved aiming at user's applications. Recently, an experiment using SRFEL combined with synchrotron radiation (SR) was begun. As the first experiment, the double-resonant excitation of Xe has been investigated by using SR and SRFEL as pump and probe lights, respectively. The relevance of making use of SRFEL for the pump/probe experiment is demonstrated.

We report results of nuclear magnetic resonance (NMR) experiments in SrCu2(BO3)2, a quasi two-dimensional spin system with a singlet ground state. When magnetic field is applied along the c-axis, each of the quadrupole split Cu resonance lines splits further into four lines. The spin-echo intensity for some of the split lines oscillates against the separation time between the pai/2 and the pai rf-pulses. These phenomena are due to strong nuclear spin-spin coupling mediated by the electronic spin system, which exists only within a pair of nuclei. Thus the results provides direct evidence for the dimer singlet gorund state in this material., Comment: 7pages, 6 figures, submitted to J. Phys.:condens. matter

A longitudinal feedback system for a storage ring free electron laser (SRFEL) has been developed at the UVSOR. Instantaneous temporal deviation of the FEL optical pulse with respect to the electron bunch is measured in the frequency domain by detecting a phase between higher harmonic components of respective revolution frequencies. The phase deviation is fed back to control the storage ring RF frequency so as to readjust the effective length of the optical cavity. Compensating for the temporal drift with the feedback system, synchronism between the FEL micropulse and the electron bunches was successfully maintained for a reasonably long time.

A new method for monitoring instantaneous bunch length has been developed on the UVSOR storage ring. Based on the bunch length dependence of the loss factor, the bunch length can be derived from the synchronous phase shift. Experiments using this method were performed to observe the bunch lengthening associated with the free electron laser (FEL) power variation. From the detuning dependence of the bunch heating, it was found that additional energy spread mostly has a constant ratio to the intracavity laser power normalized by the beam current. However, at the best synchronism region, the induced energy spread exhibits a strong non-linearity against the normalized FEL power and hence the power saturation is accomplished.

The objective of this review is to summarize the critical steps in intracellular trafficking and the principal factors involved in transgene expression by a comparison of viral and non-viral gene vectors. Intracellular trafficking of viral and non-viral gene vectors are reviewed kinetically as well as from the mechanistic point of view. The peptide-dependent specific mechanism of endosomal escape by viral vectors is compared with the non-specific mechanism of non-viral vectors. Regarding the nuclear transport of DNA, a number of recently developed strategies in non-viral vectors such as the application of nuclear localization signals or cell specific transcription factors are summarized in comparison with viral nuclear gene delivery. The molecular mechanisms of transcription and the translation of delivered genes to nucleus are also summarized in view of drug delivery systems. This information is intended to serve as a basis for developing a new gene delivery system for both viral and non-viral gene vectors. Optimizing the gene delivery system by integrating this intracellular trafficking as well as transgene expression will be required in order to develop an efficient and an safe gene delivery system.

An upgrade plan is proposed for UVSOR. The magnetic lattice will be modified while keeping the circumference and the overall shape of the ring unchanged. An emittance of 27 nm rad can be achieved, which is smaller by a factor of six than the present value. The number of straight sections will be doubled. Six straight sections will be available for insertion devices. All of them have small betatron function in vertical and are suitable for short period and narrow gap undulators, which are able to produce high brilliance soft X-rays. The new lattice has a dynamic aperture sufficiently large for injection and storage. An improvement on the main RF cavity as well as the use of the existing third harmonic RF cavity for bunch lengthening will make beam lifetime sufficiently long against strong Touschek effect.

An ultrahigh-sensitivity color high-definition television (HDTV) camera that consists of three proximity-focused image intensifier tubes of large image size (useful area: 40mm diameter) and three frame interline transfer (FIT) charge-coupled devices (CCDs) of 2/3-in. 2M pixels has been developed. The images are relayed by high-quality lenses with a reducing power of 1/3.6. The camera's sensitivity is 3000 times higher than that of a conventional HDTV CCD camera; it can take rare shots of a meteor from the ground and video images of the various hues of celestial bodies by means of an advanced astronomical telescope.

Optical cavity and control system of the UVSOR-FEL have been newly developed to improve performances and to obtain better availability for user application experiment. Lasings at visible and UV wavelength regions were successfully obtained in test experiments. By optimizing reflectivity and transmission of cavity mirrors, an average out-coupled power of more than 15 mW was achieved at a wavelength of 270 nm. Though a CW lasing zone at the top of a detuning curve was clearly obtained, an oscillation of FEL micropulse time jitter with 60 Hz appeared, which is probably due to a mechanical vibration of the cavity mirror caused by “ sound noise ” of the environment. Observed macrotemporal structure has been examined by a computer simulation including both effects of the mirror oscillation and the cavity length detuning. Results suggest that the mirror vibration should be reduced to less than 0.1 μm to suppress the amplitude of the time jitter comparable to an intrinsic temporal width of the FEL micropulse.

Spectrum of the radiation from an optical klystron is very sensitive to the beam energy spread which is an important factor for the storage ring free electron laser. In order to make use of the spectrum for a measurement of the relative energy spread, we have investigated influences of the transverse beam property on the spectrum using a helical optical klystron on the UVSOR storage ring. From analysis of the experimental results, it has been found that the most important effect comes from inhomogeneous magnetic fields and a horizontal beam size.

This paper describes a novel double-deck-shaped (DDS) gate technology for 0.1-/spl mu/m heterojunction FETs (HJFETs) which have about half the external gate fringing capacitance (C/sub f//sup ext/) of conventional T-shaped gate HJFET's. By introducing a T-shaped SiO/sub 2/-opening technique based on two-step dry-etching with W-film masks, we fabricated 0.1-/spl mu/m gate-openings which were suitable for reducing the C/sub f//sup ext/ and filling gate-metals with voidless. The fine gate-openings are completely filled with refractory WSi/Ti/Pt/Au gate-metal by using WSi-collimated sputtering and electroless Au-plating, resulting in high performance 0.1-/spl mu/m DDS gate HJFETs are fabricated. The 0.1-/spl mu/m n-Al/sub 0.2/Ga/sub 0.8/As/i-In/sub 0.15/Ga/sub 0.85/As pseudomorphic DDS gate HJFETs exhibited an excellent V/sub th/ standard-deviation (/spl sigma/V/sub th/) of 39 mV because dry-etching techniques were used in all etching-processes. Also, an HJFET covered with SiO/sub 2/ passivation film had very high performance with an f/sub T/ of 120 GHz and an f/sub max/ of 165 GHz, due to the low C/sub f//sup ext/ with the DDS gate structure. In addition, a high f/sub T/ of 151 GHz and an f/sub max/ of 186 GHz were obtained without a SiO/sub 2/ passivation film. This fabrication technology shows great promise for high-speed IC applications.

A GaAs divide-by-256/258 dual-modulus static prescaler is described. The prescaler has a pulse-swallow counter-type architecture and quasi-differential switch flip-flops as its basic circuit architecture. For the input buffer circuit, a circuit called a source-coupled push-pull circuit has been developed that can generate high-frequency complementary signals from a single-phase signal at a low supply voltage. This IC operates at up to 14.5 GHz with a power consumption of 22 mW. The power consumption is less than 1/50 of the previously reported prescalers that can operate above 10 GHz.

Single-bunch beam properties such as bunch lengthening and instability that are very important factors to develop storage ring free electron lasers (SRFEL) have been investigated on the UVSOR electron storage ring. Data were analyzed based on a model of potential-well distortion due to the impedance of the vacuum pipe. The inductive impedance was obtained to be 40 nH which is approximately 10 times larger than that of a newly constructed 3rd generation light source. In an operation with negative momentum compaction factor, the bunch shortening was observed which is also explained by which the inductive impedance dominates the single bunch property on the UVSOR ring.

To investigate variations of the bunch length and the energy spread of the electron beam on a storage ring, which are very important beam properties for storage ring free electron lasers, we have measured longitudinal electron distributions and spectra of spontaneous radiation from an optical klystron on the UVSOR storage ring operated with both signs of negative and positive momentum compaction factors. Significant differences in the bunch lengthening and the increase of the energy spread with the beam current have been found between two operations. In a case of the negative momentum compaction, a threshold beam current for the longitudinal microwave instability was observed to be very low, meanwhile “the bunch shortening” was observed.

Two kinds of TV cameras have been developed that are capable of showing the wavelengths of ultraviolet, infrared, and visible light by means of a false color method. One is sensitive to wavelengths from 250 to 650 nm (ultraviolet to yellow). It can simulate the color vision of the honey bee and other insects, reproducing the nectar guide of a flower or displaying the sex of a cabbage white moth, which is indistinguishable to the naked eye. The other is sensitive to a wider wavelength of 250 to 1,050 nm (ultraviolet to near infrared). According to the filter selected, it obtains not only visual images of invisible light information but also pictures same as those from an ordinary color camera. These TV cameras can be applied in many fields, including science, art, medicine, and industry.

High-energy gamma rays produced by intracavity Compton backscattering of a free electron laser (FEL) on the UVSOR storage ring have been observed. In the experiment, the storage ring was operated at an electron energy of 600 MeV. The FEL wavelengths were 466 and 270 nm, and then maximum photon energies were calculated to be 14.6 and 25.2 MeV, respectively. Spectra of the photons measured by using a large NaI scintillation detector were found to be consistent with a theoretical calculation.

Free-electron laser oscillation around 270 nm has been demonstrated on the UVSOR storage ring. In order to overcome an increase of cavity losses due to a shorter wavelength, the FEL gain was enhanced by reducing beam energy from an ordinal value of 500 to 430 MeV. We have investigated the reflectance of dielectric multilayer mirrors in the UV, fabricated by deposition techniques of electron-beam evaporation and ion-beam sputtering. A possibility of high-reflectance multilayer at shorter wavelength is discussed.