34 research outputs found
Hierarchical Video Generation from Orthogonal Information: Optical Flow and Texture
Learning to represent and generate videos from unlabeled data is a very
challenging problem. To generate realistic videos, it is important not only to
ensure that the appearance of each frame is real, but also to ensure the
plausibility of a video motion and consistency of a video appearance in the
time direction. The process of video generation should be divided according to
these intrinsic difficulties. In this study, we focus on the motion and
appearance information as two important orthogonal components of a video, and
propose Flow-and-Texture-Generative Adversarial Networks (FTGAN) consisting of
FlowGAN and TextureGAN. In order to avoid a huge annotation cost, we have to
explore a way to learn from unlabeled data. Thus, we employ optical flow as
motion information to generate videos. FlowGAN generates optical flow, which
contains only the edge and motion of the videos to be begerated. On the other
hand, TextureGAN specializes in giving a texture to optical flow generated by
FlowGAN. This hierarchical approach brings more realistic videos with plausible
motion and appearance consistency. Our experiments show that our model
generates more plausible motion videos and also achieves significantly improved
performance for unsupervised action classification in comparison to previous
GAN works. In addition, because our model generates videos from two independent
information, our model can generate new combinations of motion and attribute
that are not seen in training data, such as a video in which a person is doing
sit-up in a baseball ground.Comment: Our supplemental material is available on
http://www.mi.t.u-tokyo.ac.jp/assets/publication/hierarchical_video_generation_sup/
Accepted to AAAI201
Effects of mouse utricle stromal tissues on hair cell induction from induced pluripotent stem cells
BACKGROUND: Hair cells are important for maintaining our sense of hearing and balance. However, they are difficult to regenerate in mammals once they are lost. Clarification of the molecular mechanisms underlying inner ear disorders is also impeded by the anatomical limitation of experimental access to the human inner ear. Therefore, the generation of hair cells, possibly from induced pluripotent stem (iPS) cells, is important for regenerative therapy and studies of inner ear diseases. RESULTS: We generated hair cells from mouse iPS cells using an established stepwise induction protocol. First, iPS cells were differentiated into the ectodermal lineage by floating culture. Next, they were treated with basic fibroblast growth factor to induce otic progenitor cells. Finally, the cells were co-cultured with three kinds of mouse utricle tissues: stromal tissue, stromal tissue + sensory epithelium, and the extracellular matrix of stromal tissue. Hair cell-like cells were successfully generated from iPS cells using mouse utricle stromal tissues. However, no hair cell-like cells with hair bundle-like structures were formed using other tissues. CONCLUSIONS: Hair cell-like cells were induced from mouse iPS cells using mouse utricle stromal tissues. Certain soluble factors from mouse utricle stromal cells might be important for induction of hair cells from iPS cells
Effect of dietary components on renal inorganic phosphate (Pi) excretion induced by a Pi-depleted diet
Dietary inorganic phosphate (Pi) is the most important factor in the regulation of renal Pi excretion. Recent studies suggest the presence of an enteric-renal signaling axis for dietary Pi as well as the existence of a mechanism by which the intestine detects changes in luminal Pi concentrations. The mechanisms of intestinal Pi sensing, however, are unknown. In the present study, we focused on Pi depletion signals and investigated the effects of dietary components on intestinal Pi sensing. After feeding rats experimental diets for 3 days, we investigated urinary Pi excretion and plasma biochemical parameters. Renal Pi excretion was suppressed in rats fed a low-Pi diet (0.02% Pi). Elimination of dietary calcium (Ca) completely blocked the suppression of Pi excretion, suggesting that the presence of Ca is essential for the Pi depletion signal. Furthermore, a minimum Ca content of more than 0.02% was necessary for the Pi depletion signal. Magnesium, lanthanum, and strontium, which are agonists of calcium sensing receptor, instead of Ca, reduced Pi excretion.Therefore, dietary Ca appears to be important for the Pi depletion-sensing mechanism in the gastrointestinal tract. In addition, the calcium sensing receptor may be involved in the Pi depletion signal
Analytical Study on Seismic Performance of Hollow Spiral Steel Pipes under Cyclic Loading
AbstractThe importance of economical construction of infrastructures has recently increased. The application of spiral steel pipes to bridge piers is considered as one of the effective methods. Spiral steel pipes have been seldom used for bridge piers. Currently, spiral steel pipes have been mainly used as the foundations of buildings or bridges and are relatively economical because they are produced in large quantities in factories. However, roll forming processes of spiral steel pipes are different from those of bending roll pipes which have been generally used as bridge piers, so that seismic performance of spiral steel pipes may be different from that of bending roll pipes. Therefore, it is very important to grasp the ultimate strength and the ductility of spiral steel pipes. In this study, the finite element analysis was conducted for grasping the elasto-plastic behavior of hollow spiral steel pipes. Based on the analysis results, the seismic performance of hollow spiral steel pipes under compressive axial force and bending moment was examined and the influences of the structural parameters on the seismic performances of the spiral steel pipes are discussed
Phylogenetic relationships among cultivated types of Brassica rapa L. em. Metzg. as revealed by AFLP analysis
The cultivated types of Brassica rapa L. em. Metzg. consist of morphologically distinct subspecies such as turnip, turnip rape, Chinese cabbage, pak choi and pot herb mustard which are classified as ssp. rapa, ssp. oleifera, ssp. pekinensis, ssp. chinensis and ssp. nipposinica (syn. ssp. japonica), respectively. We attempted to elucidate the phylogenetic relationships among the cultivated types of B. rapa. Thirty-two accessions from the Eurasian Continent were analyzed using AFLP markers with a cultivar of B. oleracea as an outgroup. In total, 455 bands were detected in the ingroup and 392 (86.6%) were polymorphic. The Neighbor-Joining tree based on the AFLP markers indicated that the accessions of B. rapa were congregated into two groups according to geographic origin. One group consisted of ssp. rapa and ssp. oleifera of Europe and Central Asia and the other included all the subspecies of East Asia. Our results suggest that cultivars from East Asia were probably derived from a primitive cultivated type, which originated in Europe or in Central Asia and migrated to East Asia. This primitive cultivated type was probably a common ancestor of ssp. rapa and ssp. oleifera. The Neighbor-Joining tree also shows that leafy vegetables in East Asia such as ssp. pekinensis, ssp. chinensis and ssp. nipposinica were differentiated several times from the distinct cultivars of ssp. oleifera in East Asia