255 research outputs found
Physics-guided training of GAN to improve accuracy in airfoil design synthesis
Generative adversarial networks (GAN) have recently been used for a design
synthesis of mechanical shapes. A GAN sometimes outputs physically unreasonable
shapes. For example, when a GAN model is trained to output airfoil shapes that
indicate required aerodynamic performance, significant errors occur in the
performance values. This is because the GAN model only considers data but does
not consider the aerodynamic equations that lie under the data. This paper
proposes the physics-guided training of the GAN model to guide the model to
learn physical validity. Physical validity is computed using general-purpose
software located outside the neural network model. Such general-purpose
software cannot be used in physics-informed neural network frameworks, because
physical equations must be implemented inside the neural network models.
Additionally, a limitation of generative models is that the output data are
similar to the training data and cannot generate completely new shapes.
However, because the proposed model is guided by a physical model and does not
use a training dataset, it can generate completely new shapes. Numerical
experiments show that the proposed model drastically improves the accuracy.
Moreover, the output shapes differ from those of the training dataset but still
satisfy the physical validity, overcoming the limitations of existing GAN
models
Three-dimensional Simulations of Magnetospheric Accretion in a T Tauri Star: Accretion and Wind Structures Just Around Star
We perform three-dimensional magnetohydrodynamic simulations of
magnetospheric accretion in a T Tauri star to study the accretion and wind
structures in the close vicinity of the star. The gas accreting onto the star
consists of the gas from the magnetospheric boundary and the failed disk winds.
The accreting gas is commonly found as a multi-column accretion, which is
consistent with observations. A significant fraction of the angular momentum of
the accreting flows is removed by the magnetic fields of conical disk winds and
turbulent failed winds inside and near the magnetosphere. As a result, the
accretion torque is significantly reduced compared to the simple estimation
based on the mass accretion rate. The stellar spin affects the time variability
of the conical disk wind by changing the stability condition of the
magnetospheric boundary. However, the time-averaged magnetospheric radius only
weakly depends on the stellar spin, which is unlike the prediction of classical
theories that the stellar spin controls the magnetospheric radius through the
magnetic torque. The ratio of the toroidal to the poloidal field strengths at
the magnetospheric boundary, which is a key parameter for the magnetic torque,
is also insensitive to the spin; it is rather determined by the disk dynamics.
Considering newly found three-dimensional effects, we obtain a scaling relation
of the magnetospheric radius very similar to the Ghosh & Lamb relation from the
steady angular momentum transport equation.Comment: 38 pages, 21 figures. Accepted for publication in Ap
Shifting Between Cognitive and Visual Distraction: The Impact of Cognitive Ability on Distraction Caused by Secondary Tasks
We conducted an experiment in order to investigate impacts of centralexecutive (CE) functions and modality of secondary task presentation in a dualtaskexperiment. We found that shifting ability, out of three major CE functions(inhibition, shifting, and updating) was particularly important in determiningwhether primary (pedal-tracking) task performance was better in the presence ofauditory, vs. visual, presentation of the secondary task
A Neuronal Identity Code for the Odorant Receptor-Specific and Activity-Dependent Axon Sorting
SummaryIn the mouse, olfactory sensory neurons (OSNs) expressing the same odorant receptor (OR) converge their axons to a specific set of glomeruli in the olfactory bulb. To study how OR-instructed axonal fasciculation is controlled, we searched for genes whose expression profiles are correlated with the expressed ORs. Using the transgenic mouse in which the majority of OSNs express a particular OR, we identified such genes coding for the homophilic adhesive molecules Kirrel2/Kirrel3 and repulsive molecules ephrin-A5/EphA5. In the CNGA2 knockout mouse, where the odor-evoked cation influx is disrupted, Kirrel2 and EphA5 were downregulated, while Kirrel3 and ephrin-A5 were upregulated, indicating that these genes are transcribed in an activity-dependent manner. Mosaic analysis demonstrated that gain of function of these genes generates duplicated glomeruli. We propose that a specific set of adhesive/repulsive molecules, whose expression levels are determined by OR molecules, regulate the axonal fasciculation of OSNs during the process of glomerular map formation
Relationship between postprandial glucose level and carotid artery stiffness in patients without diabetes or cardiovascular disease
BACKGROUND: The aim of this study was to evaluate the relationship between postprandial glucose level and atherosclerosis in patients without diabetes and cardiovascular disease by determining carotid ultrasonographic variables and serum levels of 1,5-anhydroglucitol (1,5-AG). METHODS: The subjects were 72 patients without diabetes and cardiovascular disease being treated for hypertension or dyslipidemia. The clinical characteristics of all subjects, including the serum level of 1,5-AG, which appears to be well suited for monitoring postprandial hyperglycemia, were evaluated after an overnight fast. The average intima-media thickness (IMT) and the average pulsatility index (PI) of the right and left common carotid arteries were determined with high-resolution ultrasonography and used as ultrasonographic variables. The subjects were divided into a Lower 1,5-AG group (n = 36) and a Higher 1,5-AG group (n = 36). We evaluated the relationship between clinical characteristics and ultrasonographic variables of the carotid artery in both groups. RESULTS: The average PI in the Lower 1,5-AG group was significantly higher than that in the Higher 1,5-AG group, but the average IMT did not differ between the groups. Linear regression analysis, with the ultrasonographic variables as the dependent variables, with 1,5-AG as the independent variable, and adjusted for other clinical characteristics, showed significant correlation between 1,5-AG and the PI but not between 1,5-AG and IMT. CONCLUSION: Our results suggest that postprandial hyperglycemia increases carotid artery stiffness, but not morphological change, in patients without diabetes or cardiovascular disease
Benign Sebaceous Epithelioma with Carcinoid-like Trabecular Cell Arrangement
A case of 75-year-old woman with sebaceous epithelioma was reported. The histological features were distinct in that it had a sinusoidal and carcinoid-like growth pattern, which has been reported in its malignant counterpart. Immunostaining for adipophilin was positive in the area with lipid-laden vacuolated cells, but the rest of tumor, which had cord-like nests, was negative. MIB index was 2%. CK5/6 and p40 were positive in the cord-like nesting areas. CK7, CK20, alpha SMA, and epithelial membrane antigen were negative in both the cord-like nesting areas and the adipose-like areas. The tumor was diagnosed as sebaceous epithelioma with a trabecular pattern. Dermatopathologists should be aware of this atypical histological pattern of benign sebaceous epithelioma
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