Transient twinkle perception is induced by sequential presentation of stimuli that flicker at frequencies above the critical fusion frequency

The critical fusion frequency (CFF) is a threshold that represents the temporal limits of the human visual system. If two flickering stimuli with equal subjective luminances are presented simultaneously at different locations, the CFF is the temporal frequency above which they cannot be distinguished. However, when the stimuli are presented sequentially at the same position, a transient twinkle can be perceived around the moment of the changeover. To investigate the mechanism underlying this transient twinkle perception (TTP), we independently manipulated the luminance contrast and temporal frequency of the flicker, as well as the inter-stimulus interval (ISI). We found that TTP was greater as the luminance step was larger, it was stably perceived for flicker frequencies up to 200 Hz, and it was robust for all ISIs if flicker frequencies were below 250 Hz. For 250 and 300 Hz flicker, TTP was attenuated in the condition that 1-frame and 2-frame ISIs were inserted. These results can be explained by a simple filtering model that TTP occurs if the temporal change in a weighted moving average of stimulus luminance exceeds a certain threshold. TTP gives additional evidence that human visual system can detect the transient change of flicker stimuli at much higher temporal frequency than the CFF, by averaging mechanism of luminance

Perceptual shrinkage of a one-way motion path with high-speed motion

Back-and-forth motion induces perceptual shrinkage of the motion path, but such shrinkage is hardly perceived for one-way motion. If the shrinkage is caused by temporal averaging of stimulus position around the endpoints, it should also be induced for one-way motion at higher motion speeds. In psychophysical experiments with a high-speed projector, we tested this conjecture for a one-way motion stimulus at various speeds (4–100 deg/s) along a straight path. Results showed that perceptual shrinkage of the motion path was robustly observed in higher-speed motion (faster than 66.7 deg/s). In addition, the amount of the forwards shift at the onset position was larger than that of the backwards shift at the offset position. These results demonstrate that high-speed motion can induce shrinkage, even for a one-way motion path. This can be explained by the view that perceptual position is represented by the integration of the temporal average of instantaneous position and the motion representation

Agglomeration or Selection? The Case of the Japanese Silk-Reeling Clusters, 1908-1915

We examine two sources of productivity improvement in the specialized industrial clusters of the early twentieth century Japanese silk-reeling industry. Agglomeration improves the productivity of each plant through positive externalities, shifting plant-level productivity distribution to the right. Selection expels less productive plants through competition, truncating distribution on the left. We find no evidence confirming a right shift in the distribution in clusters or that agglomeration promotes faster productivity growth. Rather, the distribution in clusters was severely left truncated, even for younger plants. These findings imply that the plant-selection effect was the source of higher productivity in the Japanese silk-reeling clusters.Economic geography, Heterogenous firms, Industrial clusters, Productivity

Productivity Improvement in the Specialized Industrial Clusters: The Case of the Japanese Silk-Reeling Industry

We examine two sources of productivity improvement in the specialized industrial clusters. Agglomeration improves the roductivity of each plant through positive externalities, shifting plant-level productivity distribution to the right. Selection expels less productive plants through competition, truncating distribution on the left. By analyzing the data of the early twentieth century Japanese silk-reeling industry, we find no evidence confirming a right shift in the distribution in clusters or that gglomeration promotes faster productivity growth. These findings imply that the plant-selection effect was the source of higher productivity in the Japanese silk-reeling clusters.Economic geography, Heterogeneous firms, Selection, Productivity

Productivity Improvement in the Specialized Industrial Clusters: The Case of the Japanese Silk-Reeling Industry

We examine two sources of productivity improvement in the specialized industrial clusters. Agglomeration improves the productivity of each plant through positive externalities, shifting plant-level productivity distribution to the right. Selection expels less productive plants through competition, truncating distribution on the left. By analyzing the data of the early twentieth century Japanese silk-reeling industry, we find no evidence confirming a right shift in the distribution in clusters or that agglomeration promotes faster productivity growth. These findings imply that the plant-selection effect was the source of higher productivity in the Japanese silk-reeling clusters.Economic geography, Heterogeneous firms, Selection, Productivity

Engineering routine remedial work in manned machinery spaces ship: challenge for maritime autonomous surface ships

In 1987, the Japanese government launched the project “Pioneer ship” which had an automatic control system and operated with only 11 crew members, utilizing multipurpose officers and ratings. The pioneer ship is no longer practical; however, recently the concept of a more sophisticated automation system and much fewer crew in machinery spaces has become even more radical as exemplified by MASS (Maritime Autonomous Surface Ships). As far as conventional manned machinery spaces watch system is concerned, by utilizing the five senses (watching, listening, smelling, touching and tasting), duty engineering officers and ratings not only identify defects which are rarely detected by alarm systems but also deal with any defects when alarm systems detect malfunctions in machinery. Taking the engine crews’ operation into account, we need to consider not only how to introduce digitalization to the system but also train seafarers for new competences. In this paper, we categorized defects according to detectable, undetectable, remediable or irremediable cases. Taking the categorized cases into account, we analysed potential solutions for both new engine plant systems and new training systems of Maritime Autonomous Surface Ships

Electron acceleration with improved Stochastic Differential Equation method: cutoff shape of electron distribution in test-particle limit

We develop a method of stochastic differential equation to simulate electron acceleration at astrophysical shocks. Our method is based on It\^{o}'s stochastic differential equations coupled with a particle splitting, employing a skew Brownian motion where an asymmetric shock crossing probability is considered. Using this code, we perform simulations of electron acceleration at stationary plane parallel shock with various parameter sets, and studied how the cutoff shape, which is characterized by cutoff shape parameter $a$, changes with the momentum dependence of the diffusion coefficient $\beta$. In the age-limited cases, we reproduce previous results of other authors, $a\approx2\beta$. In the cooling-limited cases, the analytical expectation $a\approx\beta+1$ is roughly reproduced although we recognize deviations to some extent. In the case of escape-limited acceleration, numerical result fits analytical stationary solution well, but deviates from the previous asymptotic analytical formula $a\approx\beta$.Comment: corrected typos, 10 pages, 4 figures, 2 tables, JHEAp in pres

Manganite charge and orbitally ordered and disordered states probed by Fe substitution into Mn site in LnBaMn1.96Fe0.04O5, LnBaMn1.96Fe0.04O6 and LnBaMn1.96Fe0.04O5.5 (Ln=Y, Gd, Sm, Nd, Pr, La)

The layered manganese oxides LnBaMn1.96Fe0.04Oy (Ln=Y, Gd, Sm, Nd, Pr, La) have been synthesized for y=5, 5.5 and 6. In the oxygen-saturated state (y=6) they exhibit the charge and orbital order at ambient temperature for Ln=Y, Gd, Sm, but unordered eg-electronic system for Ln=La,Pr,Nd. Fourfold increase of quadrupole splitting was observed owing to the charge and orbital ordering. This is in agreement with the jumplike increase in distortion of the reduced perovskite-like cell for the charge and orbitally ordered manganites compared to the unordered ones. Substitution of 2 percents of Mn by Fe suppresses the temperatures of structural and magnetic transitions by 20 to 50 K. Parameters of the crystal lattices and the room-temperature M\"{o}ssbauer spectra were studied on forty samples whose structures were refined within five symmetry groups: P4/mmm, P4/nmm, Pm-3m, Icma and P2/m. Overwhelming majority of the Fe species are undifferentiated in the M\"{o}ssbauer spectra for most of the samples. Such the single-component spectra in the two-site structures are explained by the preference of Fe towards the site of Mn(III) and by the segmentation of the charge and orbitally ordered domains.Comment: 8 figures; figures 2 and 3 were revise