ASSOCIATION OF CHANGES IN SPATIOTEMPORAL VARIABLES AT EACH STEP WITH 100-M SPRINT PERFORMANCE IN PREADOLESCENT SPRINTERS

The purpose of this study was to investigate the association of acceleration and changes in spatiotemporal variables at each step with 100-m sprint performance in preadolescent sprinters. Twenty-six boys performed 100-m sprints, and their spatiotemporal variables were measured at each step. Acceleration was negatively correlated with the 100-m sprint time from the 1st to 21st step. The rates of change in step frequency were positively correlated with acceleration at the 2nd and 3rd step. Posterior to 3rd step, rates of change in step length were positively correlated with acceleration. The results suggest that the acceleration caused by increase in step frequency and step length up to reaching to the maximal sprint velocity is effective for improving the 100-m sprint time

A Novel Pollen-Pistil Interaction Conferring High-Temperature Tolerance during Reproduction via CLE45 Signaling

SummaryFlowering plants in the reproductive stage are particularly vulnerable to ambient temperature fluctuations [1–6]. Nevertheless, they maintain seed production under certain levels of exposure to temperature change. The mechanisms underlying this temperature tolerance are largely unknown. Using an in vitro Arabidopsis pollen tube culture, we found that a synthetic CLV3/ESR-related peptide, CLE45, prolonged pollen tube growth. A subsequent screen of Arabidopsis mutants of leucine-rich repeat receptor-like kinase genes identified two candidate receptors for CLE45 peptide, STERILITY-REGULATING KINASE MEMBER1 (SKM1) and SKM2. The double loss-of-function mutant was insensitive to CLE45 peptide in terms of pollen tube growth in vitro. The SKM1 protein actually interacted with CLE45 peptide. CLE45 was preferentially expressed in the stigma in the pistil at 22°C, but upon temperature shift to 30°C, its expression expanded to the transmitting tract, along which pollen tubes elongated. In contrast, both SKM1 and SKM2 were expressed in pollen. Disturbance of CLE45-SKM1/SKM2 signaling transduction by either RNAi suppression of CLE45 expression or introduction of a kinase-dead version of SKM1 into skm1 plants reduced seed production at 30°C, but not at 22°C. Taken together with the finding that CLE45 peptide application alleviated mitochondrial decay during the in vitro pollen tube culture, these results strongly suggest that the pollen-pistil interaction via the CLE45-SKM1/SKM2 signaling pathway sustains pollen performance under higher temperatures, leading to successful seed production

Configuration mixing calculation for complete low-lying spectra with the mean-field Hamiltonian

We propose a new theoretical approach to ground and low-energy excited states of nuclei extending the nuclear mean-field theory. It consists of three steps: stochastic preparation of many Slater determinants, the parity and angular momentum projection, and diagonalization of the generalized eigenvalue problems. The Slater determinants are constructed in the three-dimensional Cartesian coordinate representation capable of describing arbitrary shape of nuclei. We examine feasibility and usefulness of the method by applying the method with the BKN interaction to light 4N-nuclei, 12C, 16O, and 20Ne. We discuss difficulties of keeping linear independence for basis states projected on good parity and angular momentum and present a possible prescription.Comment: 12 pages, revtex