176 research outputs found
The Euler characteristic of an enriched category
We define Euler characteristic of a category enriched by a monoidal model
category. If a monoidal model category V is equipped with Euler characteristic
that is compatible with weak equivalences and fibrations in V, then our Euler
characteristic is also compatible with weak equivalences and fibrations in the
model structure induced by that of V. In particular, we focus on the case of
topological categories; that is, categories enriched by the category of
topological spaces. As its application, we obtain the ordinary Euler
characteristic of a cellular stratified space X by computing the Euler
characteristic of the face category C(X) induced from X
All-microwave manipulation of superconducting qubits with a fixed-frequency transmon coupler
All-microwave control of fixed-frequency superconducting quantum computing
circuits is advantageous for minimizing the noise channels and wiring costs.
Here we introduce a swap interaction between two data transmons assisted by the
third-order nonlinearity of a coupler transmon under a microwave drive. We
model the interaction analytically and numerically and use it to implement an
all-microwave controlled-Z gate. The gate based on the coupler-assisted swap
transition maintains high drive efficiency and small residual interaction over
a wide range of detuning between the data transmons.Comment: 12 pages, 8 figure
Improvement of dynamic characteristics of manipulator driven by a gas-liquid phase-change actuator using an antagonistic drive
The goal of this research is to improve the dynamic characteristics of a manipulator composed of pneumatic artificial rubber muscles driven by gas-liquid phase change. Pneumatic actuators, such as pneumatic artificial rubber muscle (PARM) or rubber bellows, have been widely used in many industrial and research fields. They have merits of being compact and lightweight. However, the large size of the compressor driving the actuator is a problem. To overcome this, the authors researched soft actuators driven by the gas-liquid phase change (GLPC) of fluorocarbon. Fluorocarbon (C5F11NO) is a substance with a relatively low boiling point (50 °C) and a low heat of evaporation (104.65 kJ/kg). The heat of evaporation of water is 2260 kJ/kg. This paper presents the overview of an actuator driven by GLPC. Then, fabrication of a manipulator using the GLPC driven PARM, and details of experiments conducted to determine manipulator characteristics are given. To improve the dynamic characteristics of the manipulator, a force control method using the antagonistic drive of two PARMs is proposed, and experiments are conducted to validate the effectiveness of the proposed method
MADGAN: unsupervised medical anomaly detection GAN using multiple adjacent brain MRI slice reconstruction.
BACKGROUND: Unsupervised learning can discover various unseen abnormalities, relying on large-scale unannotated medical images of healthy subjects. Towards this, unsupervised methods reconstruct a 2D/3D single medical image to detect outliers either in the learned feature space or from high reconstruction loss. However, without considering continuity between multiple adjacent slices, they cannot directly discriminate diseases composed of the accumulation of subtle anatomical anomalies, such as Alzheimer's disease (AD). Moreover, no study has shown how unsupervised anomaly detection is associated with either disease stages, various (i.e., more than two types of) diseases, or multi-sequence magnetic resonance imaging (MRI) scans. RESULTS: We propose unsupervised medical anomaly detection generative adversarial network (MADGAN), a novel two-step method using GAN-based multiple adjacent brain MRI slice reconstruction to detect brain anomalies at different stages on multi-sequence structural MRI: (Reconstruction) Wasserstein loss with Gradient Penalty + 100 [Formula: see text] loss-trained on 3 healthy brain axial MRI slices to reconstruct the next 3 ones-reconstructs unseen healthy/abnormal scans; (Diagnosis) Average [Formula: see text] loss per scan discriminates them, comparing the ground truth/reconstructed slices. For training, we use two different datasets composed of 1133 healthy T1-weighted (T1) and 135 healthy contrast-enhanced T1 (T1c) brain MRI scans for detecting AD and brain metastases/various diseases, respectively. Our self-attention MADGAN can detect AD on T1 scans at a very early stage, mild cognitive impairment (MCI), with area under the curve (AUC) 0.727, and AD at a late stage with AUC 0.894, while detecting brain metastases on T1c scans with AUC 0.921. CONCLUSIONS: Similar to physicians' way of performing a diagnosis, using massive healthy training data, our first multiple MRI slice reconstruction approach, MADGAN, can reliably predict the next 3 slices from the previous 3 ones only for unseen healthy images. As the first unsupervised various disease diagnosis, MADGAN can reliably detect the accumulation of subtle anatomical anomalies and hyper-intense enhancing lesions, such as (especially late-stage) AD and brain metastases on multi-sequence MRI scans
ALSET - Japanese Air Launch System Ground Tests and Applications
The Air Launch System Enabling Technology (ALSET) project is a Japanese Ministry of Economy, Trade and Industry (METI) funded project whose purpose is to study air launch orbital payload delivery systems and related technologies. The project is a first step toward an operational commercial air launch system that will use a multistage solid rocket to deliver small payloads on the order of 100 to 200 kilograms into Low Earth Orbit (LEO). An air drop type launch approach to space transportation provides high reliability, flexibility, and responsiveness to meet the future needs of small satellite operators. ALSET culminates in a series of drop tests of an inert launch vehicle (a mass simulator) to demonstrate the technologies necessary for the operational system. The baseline system design uses a carriage extraction system method whereby the rocket is extracted from a C-130 aircraft on a TYPE-V platform. Two 28-foot extraction parachutes are used to pull the platform from the aircraft. Three 100-foot cargo parachutes are then deployed for deceleration prior to release of the rocket from the platform for launch. The baseline test site selected for the drop test is the Yuma Test Center (YTC) in Arizona, USA. The large drop zones available at the YTC are ideal for ALSET testing. Additionally, the YTC’s considerable experience with similar test activities, including the NASA Ares Jumbo Drop Test Vehicle drop tests, minimizes technical risks. The authors’ efforts to date completed the Critical Design Review (CDR) for the ALSET Drop Test in February and March 2015. The ALSET program is now ready for manufacturing for the ALSET Drop Test. As the prospective applications of ALSET to C4ISR missions, two case studies were conducted. The studies demonstrated the effectiveness of the air launch system. The responsiveness and flexibility of the air launch system enables small satellites to collect the ground information desired in short time, and to observe the target highfrequently by sequential satellite launches and forming a constellation
Cross-sectional and longitudinal study of association between circulating thiobarbituric acid-reacting substance levels and clinicobiochemical parameters in 1,178 middle-aged Japanese men - the Amagasaki Visceral Fat Study
Azilsartan inhibits inflammation-triggered bone resorption and osteoclastogenesis in vivo via suppression of TNF-α expression in macrophages
IntroductionHypertension is a major risk factor for cardiovascular disease (CVD) and is associated with increased bone loss due to excessive activity of the local renin-angiotensin system (RAS). Angiotensinogen/Angiotensin (ANG) II/Angiotensin II type 1 receptor (AT1R) axis is considered as the core axis regulating RAS activity. Azilsartan is an FDA-approved selective AT1R antagonist that is used to treat hypertension. This study aimed to determine whether azilsartan affects formation of osteoclast, resorption of bone, and the expression of cytokines linked with osteoclastogenesis during lipopolysaccharide (LPS)-triggered inflammation in vivo.MethodsIn vivo, following a 5-day supracalvarial injection of LPS or tumor necrosis factor-alpha (TNF-α) with or without azilsartan, the proportion of bone resorption and the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, which are identified as osteoclasts on mice calvariae were counted. The mRNA expression levels of TRAP, cathepsin K, receptor activator of NF-κB ligand (RANKL), and TNF-α were also evaluated. In vitro, the effect of azilsartan (0, 0.01, 0.1, 1, and 10 μM) on RANKL and TNF-α-triggered osteoclastogenesis were investigated. Also, whether azilsartan restrains LPS-triggered TNF-α mRNA and protein expression in macrophages and RANKL expression in osteoblasts were assessed. Furthermore, western blotting for analysis of mitogen-activated protein kinases (MAPKs) signaling was conducted.ResultsAzilsartan-treated calvariae exhibited significantly lower bone resorption and osteoclastogenesis than those treated with LPS alone. In vivo, LPS with azilsartan administration resulted in lower levels of receptor activator of RANKL and TNF-α mRNA expression than LPS administration alone. Nevertheless, azilsartan did not show inhibitory effect on RANKL- and TNF-α-triggered osteoclastogenesis in vitro. Compared to macrophages treated with LPS, TNF-α mRNA and protein levels were lower in macrophages treated by LPS with azilsartan. In contrast, RANKL mRNA and protein expression levels in osteoblasts were the same in cells co-treated with azilsartan and LPS and those exposed to LPS only. Furthermore, azilsartan suppressed LPS-triggered MAPKs signaling pathway in macrophages. After 5-day supracalvarial injection, there is no difference between TNF-α injection group and TNF-α with azilsartan injection group.ConclusionThese findings imply that azilsartan prevents LPS-triggered TNF-α production in macrophages, which in turn prevents LPS-Triggered osteoclast formation and bone resorption in vivo
Mid and Far Infrared Properties of a Complete Sample of Local AGNs
We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly
complete sample of local Active Galactic Nuclei (AGNs) detected in the
Swift/BAT all sky hard X-ray (14-195 keV) survey, based on the cross
correlation with the AKARI infrared survey catalogs complemented by those with
IRAS and WISE. Out of 135 non-blazer AGNs in the Swift/BAT 9 month catalog, we
obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22,
and/or 25 um band. We find good correlation between their hard X-ray and MIR
luminosities over 3 orders of magnitude (42< log lambda L_{lambda}(9, 18 um)<
45), which is tighter than that with the FIR luminosities at 90 um. This
suggests that thermal emission from hot dusts irradiated by the AGN emission
dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the
same correlation, implying isotropic infrared emission, as expected in clumpy
dust tori rather than homogeneous ones. We find excess signals around 9 um in
the averaged infrared spectral energy distribution from heavy obscured "new
type" AGNs with small scattering fractions in the X-ray spectra. This could be
attributed to the PAH emission feature, suggesting that their host galaxies
have strong starburst activities.Comment: 14 pages, 8 figures, accepted for publication in Ap
The Hayabusa Spacecraft Asteroid Multi-Band Imaging Camera: AMICA
The Hayabusa Spacecraft Asteroid Multiband Imaging Camera (AMICA) has
acquired more than 1400 multispectral and high-resolution images of its target
asteroid, 25143 Itokawa, since late August 2005. In this paper, we summarize
the design and performance of AMICA. In addition, we describe the calibration
methods, assumptions, and models, based on measurements. Major calibration
steps include corrections for linearity and modeling and subtraction of bias,
dark current, read-out smear, and pixel-to-pixel responsivity variations. AMICA
v-band data were calibrated to radiance using in-flight stellar observations.
The other band data were calibrated to reflectance by comparing them to
ground-based observations to avoid the uncertainty of the solar irradiation in
those bands. We found that the AMICA signal was linear with respect to the
input signal to an accuracy of << 1% when the signal level was < 3800 DN. We
verified that the absolute radiance calibration of the AMICA v-band (0.55
micron) was accurate to 4% or less, the accuracy of the disk-integrated spectra
with respect to the AMICA v-band was about 1%, and the pixel-to-pixel
responsivity (flatfield) variation was 3% or less. The uncertainty in
background zero-level was 5 DN. From wide-band observations of star clusters,
we found that the AMICA optics have an effective focal length of 120.80 \pm
0.03 mm, yielding a field-of-view (FOV) of 5.83 deg x 5.69 deg. The resulting
geometric distortion model was accurate to within a third of a pixel. We
demonstrated an image-restoration technique using the point-spread functions of
stars, and confirmed that the technique functions well in all loss-less images.
An artifact not corrected by this calibration is scattered light associated
with bright disks in the FOV.Comment: 107 pages, 22 figures, 9 tables. will appear in Icaru
On the origin and evolution of the asteroid Ryugu: A comprehensive geochemical perspective
Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher δ18O, Δ17O, and ε54Cr values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10’s of km), <2.6 Myr after CAI formation. Subsequently, the Ryugu progenitor planetesimal was fragmented and evolved into the current asteroid Ryugu through sublimation
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