401 research outputs found
O(a) Improvement of 2D N=(2,2) Lattice SYM Theory
We perform a tree-level O(a) improvement of two-dimensional N=(2,2)
supersymmetric Yang-Mills theory on the lattice, motivated by the fast
convergence in numerical simulations. The improvement respects an exact
supersymmetry Q which is needed for obtaining the correct continuum limit
without a parameter fine tuning. The improved lattice action is given within a
milder locality condition in which the interactions are decaying as the
exponential of the distance on the lattice. We also prove that the
path-integral measure is invariant under the improved Q-transformation.Comment: 42 pages, no figure; (v2) published version in Nucl. Phys.
Structures of Graphene/Cobalt Interfaces in Cobalt-Encapsulated Carbon Nanocapsules
Carbon nanocapsules (CNCs) encapsulating cobalt (Co) nanoparticles with a face-centered-cubic structure were synthesized by a gas-evaporation method and were
observed by high-resolution transmission electron microscopy. The Co nanoparticles revealed
polyhedral shapes; they were truncated by low-index facets. The surfaces of Co nanoparticles
were surrounded by graphene layers. The atomic configuration and interlayer spacing at the
graphene/cobalt interfaces were investigated
Complication and hysteresis of the self-sustaining motion of a molecular-machine assembly caused by the directionality of the applied light energy
Living organisms show self-sustained motion, make behavioural decisions in
response to their environment, and replicate themselves in a genetic manner.
Recently, nanometre-sized molecular machines have been assembled to realise
macroscopic systems that exhibit self-sustaining dynamics. However, it is
unclear how such systems can acquire the ability to make decisions in response
to their environment. We have previously reported that the behaviour of a
light-driven self-oscillating crystal becomes complicated when the driving
light is polarised. Here, we reveal by incorporating a theoretical analysis
that the apparent complexity is due to the orientation of the crystal relative
to the incident light. An additional reason for this complexity is that the
components remember the polarity of the preceding light input. Our results
provide a new concept, i.e., collaboration between a motor molecule to achieve
self-sustaining motion and a responsive machine for storing information to
realise self-governed dynamics in a multimolecular architecture
A 7R Spatial Linkage for Ankle Rehabilitation with an Arbitrary Ankle Rotation Axis
In this paper, a 7R spatial linkage for ankle rehabilitation was proposed. Thanks to its kinematic geometry, the output joint, which is accommodated by the patient\u27s ankle, of the linkage can possess an arbitrary joint axis at any configuration. This advantage allows the patient achieving a flexible ankle motion in 3-D space while performing the rehabilitation exercise. The design concept of the 7R linkage is explained, and the displacement and force relationships between the input and output joints (i.e., the motor and patient\u27s ankle) are analyzed through an equivalent RSSR linkage. A prototype is built to validate the proposed design concept
Galactic distributions of carbon- and oxygen-rich AGB stars revealed by the AKARI mid-infrared all-sky survey
Context: The environmental conditions for asympotic giant branch (AGB) stars
to reach the carbon-rich (C-rich) phase are important to understand the
evolutionary process of AGB stars. The difference between the spatial
distributions of C-rich and oxygen-rich (O-rich) AGB stars is essential for the
study of the Galactic structure and the chemical evolution of the interstellar
medium (ISM). Aims: We quantitatively investigate the spatial distributions of
C-rich and O-rich AGB stars in our Galaxy. We discuss the difference between
them and its origin. Methods: We classify a large number of AGB stars newly
detected by the AKARI id-infrared all-sky survey. In the color-color diagrams,
we define their occupation zones based on the locations of known objects. We
then obtain the spatial distributions of C-rich and O-rich AGB stars, assuming
that they have the same luminosity for a given mass-loss rate. Results: We find
that O-rich AGB stars are concentrated toward the Galactic center and that the
density decreases with Galactocentric distance, whereas C-rich AGB stars show a
relatively uniform distribution within about 8kpc of Sun. Conclusion: Our
result confirms the trends reported in previous studies and extends them to a
Galactic scale. We discuss the relations between our result, the Galactic
metallicity gradient, and the chemical evolution of the ISM in our Galaxy.Comment: 13 pages, 24 figures, Accepted for A&
Development of the analog ASIC for multi-channel readout X-ray CCD camera
We report on the performance of an analog application-specific integrated
circuit (ASIC) developed aiming for the front-end electronics of the X-ray
CCDcamera system onboard the next X-ray astronomical satellite, ASTRO-H. It has
four identical channels that simultaneously process the CCD signals.
Distinctive capability of analog-to-digital conversion enables us to construct
a CCD camera body that outputs only digital signals. As the result of the
front-end electronics test, it works properly with low input noise of =<30 uV
at the pixel rate below 100 kHz. The power consumption is sufficiently low of
about 150 mW/chip. The input signal range of 720 mV covers the effective energy
range of the typical X-ray photon counting CCD (up to 20 keV). The integrated
non-linearity is 0.2% that is similar as those of the conventional CCDs in
orbit. We also performed a radiation tolerance test against the total ionizing
dose (TID) effect and the single event effect. The irradiation test using 60Co
and proton beam showed that the ASIC has the sufficient tolerance against TID
up to 200 krad, which absolutely exceeds the expected amount of dose during the
period of operating in a low-inclination low-earth orbit. The irradiation of Fe
ions with the fluence of 5.2x10^8 Ion/cm2 resulted in no single event latchup
(SEL), although there were some possible single event upsets. The threshold
against SEL is higher than 1.68 MeV cm^2/mg, which is sufficiently high enough
that the SEL event should not be one of major causes of instrument downtime in
orbit.Comment: 16 pages, 6 figure
A spectrum of clinical manifestations caused by host immune responses against Epstein-Barr virus infections.
Epstein-Barr virus (EBV), or human herpesvirus 4 (HHV-4), infects the vast majority of adults worldwide, and establishes both nonproductive (latent) and productive (lytic) infections. Host immune responses directed against both the lytic and latent cycle-associated EBV antigens induce a diversity of clinical symptoms in patients with chronic active EBV infections who usually contain an oligoclonal pool of EBV-infected lymphocyte subsets in their blood. Episomal EBV genes in the latent infection utilize an array of evasion strategies from host immune responses: the minimized expression of EBV antigens targeted by host cytotoxic T lymphocytes (CTLs), the down-regulation of cell adhesion molecule expression, and the release of virokines to inhibit the host CTLs. The oncogenic role of latent EBV infection is not yet fully understood, but latent membrane proteins (LMPs) expressed during the latency cycle have essential biological properties leading to cellular gene expression and immortalization, and EBV-encoded gene products such as viral interleukin-10 (vIL-10) and bcl-2 homologue function to survive the EBV-infected cells. The subsequent oncogenic DNA damage may lead to the development of neoplasms. EBV-associated NK/T cell lymphoproliferative disorders are prevalent in Asia, but quite rare in Western countries. The genetic immunological background, therefore, is closely linked to the development of EBV-associated neoplasms.</p
Gastric Mucosal Changes Caused by Lugol's Iodine Solution Spray: Endoscopic Features of 64 Cases on Screening Esophagogastroduodenoscopy
Aim. To clarify the endoscopic mucosal change of the stomach caused by Lugol's iodine solution spray on screening esophagogastroduodenoscopy (EGD).
Methods. Sixty-four consecutive patients who underwent EGD for esophageal squamous cell
carcinoma screening were included in this study. The records for these patients included gastric
mucosa findings before and after Lugol's iodine solution was sprayed. The endoscopic findings of
the greater curvature of the gastric body were retrospectively analyzed based on the following
findings: fold thickening, exudates, ulcers, and hemorrhage. Results. Mucosal changes occurred after Lugol's solution spray totally in 51 patients (80%). Fold thickening was observed in all 51 patients (80%), and a reticular pattern of white lines was found on the surface of the thickened gastric folds found in 28 of the patients (44%). Exudates were observed in 6 patients (9%). Conclusion. The gastric mucosa could be affected by Lugol's iodine; the most frequent endoscopic finding of this effect is gastric fold thickening, which should not be misdiagnosed as a severe gastric disease
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