Fukuyama City University

About: Fukuyama City University is a education organization based out in Fukuyama, Japan. It is known for research contribution in the topics: Accommodation & Permafrost. The organization has 15 authors who have published 42 publications receiving 212 citations. The organization is also known as: Fukuyama Shiritsu Daigaku.

Vegetation and Permafrost Thaw Depth 10 Years after a Tundra Fire in 2002, Seward Peninsula, Alaska

Abstract: The recovery of tundra vegetation and the depth of permafrost thaw were observed on the Seward Peninsula, Alaska, the site of a wildfire in 2002. The study compared the vegetation in burned and adjacent unburned tundra from 5 to 10 years post-fire. The effects of the fire on the vegetation varied between species and were spatially variable at the stand scale. The cover of evergreen shrubs, bryophytes, and lichens was still drastically decreased 5 years after the fire and had not recovered even 10 years after the fire. By contrast, the cover of graminoids, especially Eriophorum vaginatum, and of the deciduous shrub Vaccinium uliginosum increased. The depth of permafrost thaw increased, and its spatial pattern was related to vegetation structure; specifically, deeper thaw corresponded to graminoid-rich areas, and shallower thaw corresponded to shrub-rich areas. As the E. vaginatum cover increased, the thaw depth recovered to that of the unburned area, and the spatial variation had disappeared 10 ye...

Simultaneous measurement of lens accommodation and convergence in natural and artificial 3D vision

Abstract: Recent advances in 3D technology have been accompanied by increasing complaints of visual fatigue. The usual explanation for such fatigue is that accommodation and convergence are mismatched during stereoscopic vision. The aim of this study was to measure fixation distances between lens accommodation and convergence in young subjects while they viewed real objects and 3D video clips. Measurements were made using an original instrument. The 3D video clips were presented to subjects using a liquid crystal shutter glass system. The results showed that when viewing real objects, the diopter values of subjects' accommodation and convergence were similar and changed periodically. This measurement method was thus considered to be appropriate for the measurement of stereoscopic vision. We also investigated lens accommodation and convergence when subjects viewed 3D video clips. Both accommodation and convergence were found to move along with the virtual position of 3D video clips. Therefore, there was little discrepancy between accommodation and convergence during the viewing of 3D images.

Children's Media Use and Self-Regulation Behavior: Longitudinal Associations in a Nationwide Japanese Study.

Abstract: Objective The effect of media use on child behavior has long been a concern. Although studies have shown robust cross-sectional relations between TV viewing and child behavior, longitudinal studies remain scarce. Methods We analyzed the Longitudinal Survey of Babies, conducted by Japan's Ministry of Health, Labour and Welfare since 2001. Among 53,575 families, 47,010 responded to the baseline survey; they were followed up every year for 8 years. Complete data were available for longitudinal analysis among 32,439 participants. Daily media use (TV viewing and video game-playing hours at ages 3, 4, and 5 years) was used as the main exposure. We employed an index of the children's self-regulatory behavior as the outcome variable. Odds ratios and 95 % confidence intervals (CIs) were estimated. Results Among boys, longer TV-viewing times at ages 4 and 5 were related to problematic self-regulatory behavior. Compared with boys who watched just 1-2 h of TV a day, those who watched it 4-5 h had a 1.79-fold greater risk (CI 1.22-2.64) of problematic self-regulatory behavior, according to parental report. Among girls, similar results were evident at ages 4 and 5 (e.g., adjusted odds ratios for 4-5 h daily viewing versus 1-2 h at age 4: 2.59; 95 % CI 1.59-4.22). Video games may have a protective effect on the risk of problematic self-regulatory behavior at ages 3 and 5. Conclusion Longer daily exposure to TV during early childhood (age 4-5) may be associated with subsequent problematic child self-regulatory behavior.

Analysis of the Sources of Variation in L-band Backscatter From Terrains With Permafrost

Abstract: Simultaneous field data collections and Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar (PALSAR) full polarimetry observations were performed in Ulaanbaatar (Mongolia) and Alaska (USA). Permafrost is present at the Alaska test sites. Backscattering copolarization ( σco-pol0) values derived from the PALSAR data were compared with those calculated using the integrated equation method (IEM) model, a popular theoretical model describing surface scattering. PALSAR data taken in Ulaanbaatar matched the IEM model results to within a few decibels, whereas data taken in Alaska were 5 to 7 dB lower than those calculated using the IEM model. On the other hand, the σcross-pol0 (σVH0) components estimated from the Oh model were well matched to the PALSAR data in both Ulaanbaatar and Alaska. Moisture levels of the sphagnum moss layer in Alaska were estimated to be about 10% while moisture levels of the underlying organic and mineral layers were 25% to 79%; the moisture values of the organic and mineral layers were factored into the IEM and Oh models. When surface moisture levels of 10% were assumed for Alaska ground conditions, the σco-pol0 values calculated using the IEM model and those derived from the PALSAR data were well matched. From these observations, we conclude that the sphagnum moss layer, which is a seasonally unfrozen layer that occurs above permafrost, plays an important role in radar backscattering processes in permafrost regions and is a main contributor to the σco-pol0 backscattering component; the underlying organic and mineral layers contribute mainly to the σcross-pol0 backscattering component. A two-layer model was applied to the data from a test site in Alaska; the model described the co- and cross-polarization backscatter (σ0) derived from PALSAR data with off-nadir angles of 21.5° and 34.3°.