Feasibility of an Incoherent-scatter Radar Aboard the Space Shuttle

The results of a preliminary study to investigate the feasibility of conducting an incoherent scatter radar experiment on board the space shuttle are presented. The results indicate that such an experiment is technically feasible. The more difficult questions to answer are whether the system can be made flexible enough to justify the problems and costs involved. The design parameters and the tradeoffs that are available in the consideration of these questions are evaluated. Some of the more serious limitations pertain to: (1) the presence of ground clutter and F region auroral clutter; (2) available average power; (3) weight and volume associated with required antenna size, transmitter, and energy storage devices; and (4) antenna breakdown associated with high power transmitter problems

THREE TECHNIQUES OF SKI JUMP TAKE-OFF MODELED BY CHANGES OF JOINT ANGLE

INTRODUCTION: In ski jumping, take-off action is the most important factor for ascent force. Jumpers should aim for optimum movements of the joints, because reaction force is the result of the integrated kinetic parameters of each joint or segment. In our recent studies, three techniques of take-off action were classified by manner of joint power generation. However, such kinetic parameters are difficult to explain in coaching situations. It would be more useful for coaching to represent the three techniques of take-off action by joint angle rather than joint power. The purpose of this study is to establish visual models of ski jump take-off action of world class jumpers based on changes of joint angle which would be especially useful in coaching. METHOD: The take-off actions were analyzed from videos taken at Hakuba Intercontinental Cup summer competition at 1997. Camera speed was 240 frames per second. The data from the videos were collected by computer. An inverse kinematics solution was applied to analysis. Jump performance of four jumpers, who received first prize in the team competition of Nagano Olympic games, was analyzed. RESULTS: The maximum value of angular velocity in the thigh was observed at close to the take-off platform edge in all jumpers. Peak angular velocity in the thigh was larger than in the trunk segment. The action at the hip joint represented the characteristics of jumping techniques rather than the action at the knee joint. The technique was classified by three manners of angular velocity. The three types of jump action were represented simply as visual models. In the technique of Type-A, motion was observed with regular order in each joint. The angular velocity of the trunk stayed at 2 rad/sec until the thigh’s angular velocity’s appearance. Type-A can be defined simply as an action moving from hip to knee joint. In technique Type-B, the angular velocity in the thigh was 4 rad/sec, higher than in the trunk at the initial jump action, and after some delay, the value in the trunk raised up from a negative value. Action Type-B can be defined simply as moving from knee to hip joint. In the last technique, Type-C, both the trunk and thigh angular velocities increased synchronously. Both hip and knee joints were extended at the same time. Type-C can be defined simply as the technique of synchronous movement at the knee and hip joint. These motions classified by changes of joint angle were shown by three visual models from Type-A to C. CONCLUSION: Three types of jump action could be represented simply by joint angle as visual models. There are advantages and risks involving jump hieght and the amount of body area subjected to aerodynamic drag force associated with each technique

Performance Evaluation of SCTP wth Adaptive Multistreamiing over LEO Satellite Networks

科研費報告書収録論文(課題番号:17500030/研究代表者:加藤寧/インターネットと高親和性を有する次世代低軌道衛星ネットワークに関する基盤研究

Supporting IP/LEO satellite networks by handover-independent IP mobility management

科研費報告書収録論文(課題番号:14380172・基盤研究(B)(2) ・H14～H15/研究代表者:根元, 義章/トラヒックパターンの時系列解析に基づく次世代広域不正アクセス自動追跡システム

Generation of cytotoxic T cell responses to an HLA-A24 restricted epitope peptide derived from wild-type p53

Mutations in the p53 gene are the most common genetic alterations found in human tumours, and these mutations result in high levels of p53 protein in the tumour cells. Since the expression levels of wild-type p53 in nonmalignant tissue are usually much lower in contrast, the p53 protein is an attractive target for cancer immunotherapy. We tested p53 encoded HLA-A24 binding peptides for their capacity to elicit anti-tumour cytotoxic T lymphocytes (CTL) in vitro. These peptides were in murine p53-derived cytotoxic peptides, which were being presented to CTL by H-2K d and H-2K b molecules, because the HLA-A24 peptide binding motifs were similar to the H-2K d and H-2K b. For CTL induction, we used CD8+T lymphocytes from the peripheral blood mononuclear cells (PBMC) of healthy donors and the peptides from pulsed dendritic cells as antigen-presenting cells. We identified the peptide, p53-161 (AIYKQSQHM), which was capable of eliciting CTL lines that lysed tumour cells expressing HLA-A24 and p53. The effectors lysed C1RA24 cells (p53+, HLA-A*2402 transfectant), but not their parental cell lines C1R (p53+, HLA-A,B null cell). These results strongly indicate that the CTL exerts cytotoxic activity in HLA-A24's restricted manner. The identification of this novel p53 epitope for CTL offers the possibility to design and develop specific immunotherapeutic approaches for treating tumours with p53 mutation in HLA-A24-positive patients. © 2001 Cancer Research Campaign http://www.bjcancer.co

Frustrated minority spins in GeNi2O4

Recently, two consecutive phase transitions were observed, upon cooling, in an antiferromagnetic spinel GeNi$_2$O$_4$ at $T_{N1}=12.1$ K and $T_{N2}=11.4$ K, respectively \cite{matsuno, crawford}. Using unpolarized and polarized elastic neutron scattering we show that the two transitions are due to the existence of frustrated minority spins in this compound. Upon cooling, at $T_{N1}$ the spins on the \kagome planes order ferromagnetically in the plane and antiferromagnetically between the planes (phase I), leaving the spins on the triangular planes that separate the \kagome planes frustrated and disordered. At the lower $T_{N2}$, the triangular spins also order in the $$ plane (phase II). We also present a scenario involving exchange interactions that qualitatively explains the origin of the two purely magnetic phase transitions

Cu-NMR study on the disordered quantum spin magnet with the Bose-glass ground state

Cu-NMR study has been performed on the disordered spin-gap system Tl1-xKxCuCl3 In the high-field H > HC=\Delta/\mu_B, where \Delta is the spin-gap, the hyperfine field becomes extremely inhomogeneous at low temperatures due to the field-induced magnetic order, indicating that the ordered spin state must be different from the pure TlCuCl3. In the low field H < HC, a saturating behavior in the longitudinal nuclear spin relaxation rate 1/T1 was observed at low temperatures, indicating existence of the magnetic ground state proposed to be Bose-glass phase by Fisher.Comment: RHMF200