82 research outputs found
Pgx: Hardware-accelerated Parallel Game Simulators for Reinforcement Learning
We propose Pgx, a suite of board game reinforcement learning (RL)
environments written in JAX and optimized for GPU/TPU accelerators. By
leveraging auto-vectorization and Just-In-Time (JIT) compilation of JAX, Pgx
can efficiently scale to thousands of parallel executions over accelerators. In
our experiments on a DGX-A100 workstation, we discovered that Pgx can simulate
RL environments 10-100x faster than existing Python RL libraries. Pgx includes
RL environments commonly used as benchmarks in RL research, such as backgammon,
chess, shogi, and Go. Additionally, Pgx offers miniature game sets and baseline
models to facilitate rapid research cycles. We demonstrate the efficient
training of the Gumbel AlphaZero algorithm with Pgx environments. Overall, Pgx
provides high-performance environment simulators for researchers to accelerate
their RL experiments. Pgx is available at https://github.com/sotetsuk/pgx.Comment: 9 page
Clinical utility of the Bosniak classification version 2019:Diagnostic value of adding magnetic resonance imaging to computed tomography examination
Purpose: To assess the impact of the updated Bosniak classification (BC2019) for cystic renal masses (CRMs) on interobserver agreement between radiologists and urologists and the diagnostic value of adding MRI to CT examination (combined CT/MRI). Method: This study included 103 CRMs from 83 consecutive patients assessed using contrast-enhanced CT and MRI between 2010 and 2016. Nine readers in three groups (three radiologists, three radiology residents, and three urologists) reviewed CT alone and the combined CT/MRI using BC2019. Bosniak category was determined by consensus in each group for diagnosing malignancy, with a cut-off category of ?>= III. Interobserver agreement was assessed using Fleiss' kappa values. The effect of CT or combined CT/MRI on the diagnosis of malignancy was assessed using McNemar's test. Results: Interobserver agreement of BC2019 for CT alone was substantial for radiologists and residents, moderate for urologists (0.77, 0.63, and 0.58, respectively). Interobserver agreement of BC2019 for combined CT/MRI was substantial for all three groups (radiologists: 0.78; residents: 0.65; and urologists: 0.61). Among residents, the sensitivity/specificity/accuracy rates of combined CT/MRI vs. CT alone were 82.1/74.7/76.7% vs. 75.0/66.7/68.9%, and specificity and accuracy were significantly higher for combined CT/MRI than that for CT alone (p = 0.03 and 0.008, respectively). Similarly, sensitivity/specificity/accuracy values were significantly higher for combined CT/MRI among urologists (78.6/73.3/74.8% vs. 64.3/64.0/64.1%, p = 0.04/0.04/0.008). However, sensitivity/specificity/accuracy did not significantly differ between the two among radiologists (89.3/74.7/78.6% vs. 85.7/73.3/76.7%, p = 0.32/0.56/0.32). Conclusions: Combined CT/MRI is useful for diagnosing malignancy in patients with CRMs using BC2019, especially for non-expert readers
Nowcast and forecast of galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes in magnetosphere and ionosphere – Extension of WASAVIES to Earth orbit
Real-time estimation of cosmic-ray fluxes on satellite orbits is one of the greatest challenges in space weather research. Therefore, we develop a system for nowcasting and forecasting the galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes at any location in the magnetosphere and ionosphere during ground-level enhancement (GLE) events. It is an extended version of the WArning System for AVIation Exposure to SEP (WASAVIES), which can determine event profiles by using real-time data of the count rates of several neutron monitors (NMs) at the ground level and high-energy proton fluxes observed by Geostationary Operational Environmental Satellites (GOES) satellites. The extended version, called WASAVIES-EO, can calculate the GCR and SEP fluxes outside a satellite based on its two-line element (TLE) data. Moreover, organ absorbed-dose and dose-equivalent rates of astronauts in the International Space Station (ISS) can be estimated using the system, considering its shielding effect. The accuracy of WASAVIES-EO was validated based on the dose rates measured in ISS, as well as based on high-energy proton fluxes observed by POES satellites during large GLEs that have occurred in the 21st century. Agreement between the nowcast and forecast dose rates in ISS, especially in terms of their temporal structures, indicates the usefulness of the developed system for future mission operations
Protein-Energy Malnutrition in Patients with Liver Cirrhosis
Protein-energy malnutrition (PEM) is frequently seen in patients with liver cirrhosis. This condition is associated with a poorprognosis and reduced survival. We investigated the protein and energy metabolic status, including serum albumin concentration,and resting energy expenditure (REE) and respiratory quotient (RQ) measured by indirect calorimetry in 23 patients withliver cirrhosis (8 men and 15 women; mean age, 60.3 years). The median value of %REE (measured REE / predicted REE)was highest in Child-Pugh grade A and lowest in grade C, and the range of RQ tended to be highest in Child-Pugh grade Aand lowest in grade C, although there were not statistically significant (p=0.871 and 0.664, respectively). Serum triglycerideconcentration was significantly lower in patients who had an RQ less than 0.85 than in patients who had an RQ of 0.85 ormore, and free fatty acid tended to be higher in patients who had an RQ less than 0.85 than in patients who had an RQ of 0.85or more. Of the 23 patients, 78.3% were in a state of protein and/or energy malnutrition and 47.8% had PEM. Our results suggestthat %REE and RQ were not significantly associated with liver function, but the oxidation rate of fat was increased in advancedliver cirrhosis. A longitudinal study in a large population is needed to determine the efficacy of %REE and RQ measurementsfor adequate nutritional treatment and improvement of patient outcome
Correction Notice to: Nowcast and forecast of galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes in magnetosphere and ionosphere – Extension of WASAVIES to Earth orbit
The Relationship between Energy Expenditure and Type or Stage of Cancer
Malnutrition commonly occurs in patients with cancer. This situation can be associated with increased morbidity and mortality.The etiology is not clearly understood but decreased energy intake and increased energy expenditure may be involved. Weaimed to investigate the energy metabolic status including energy expenditure in patients with various cancers. The clinicalfeatures and energy metabolic status measured by indirect calorimetry of 74 patients with cancer (50 men and 24 women;mean age, 64.7 years) were obtained from the medical records. Hypermetabolism was more common and REE/kg (resting energyexpenditure / kg body weight) seems to be more reliable in estimating the true energy expenditure than %REE (measuredREE / predicted REE). The REE/kg and VO2 /kg (oxygen consumption per minute / kg body weight) varied among cancertypes, i.e., they were significantly higher in gastric cancer than in hepatocellular carcinoma. Moreover, REE/kg and VO2/kg wassignificantly higher in cancer stage IV than in stage I, or stages I and II. Patients with or at risk for malnutrition should receiveappropriate nutritional support, which has to be personalized according to tumor site, tumor stage, and the nutritional statusof the patient. This nutritional support should improve not only the patients\u27 quality of life but also their survival
Reproduction, growth rate and dispersal of the dark chub, Candidia sieboldii, as estimated by using the mark–release–recapture method
We investigated the breeding season, growth rate and dispersal of the dark chub, Candidia sieboldii, an endangered species in Japan. A mark–release–recapture survey was performed in three branches of the Ishizu River system in Osaka Prefecture, Japan, between May 2012 and August 2013. A total of 963 individuals were marked in one river branch and 275 (29%) were recaptured at least once in the same river section. The breeding season was determined to be June–August, and the size at maturity for both males and females was estimated at about 70 mm standard length. Growth rates calculated from standard lengths of recaptured individuals were higher between April and September than between October and March. Among 963 marked individuals, only a single fish was found 500 m downstream from the release point. Moreover, although we released 409 more marked individuals in the three branches to follow inter-branch dispersal between September and December 2013, we observed none. These results indicate that this species has low dispersal and a short lifespan of 1–2 years. This short lifespan could increase the risk of breeding failure, and the low frequency of dispersal, restricted by weirs, could make population re-establishment and recovery difficult
Mineral classification from quantitative X-ray maps using neural network: Application to volcanic rocks
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