1,314 research outputs found
A COMPARISON OF JAPANESE FINALISTS TO OTHER FINALISTS IN THE 100 m SWIMMING RACES AT THE SYDNEY OLYMPIC GAMES
The purpose of this study was to compare the performance in 100 m swimming events at the Sydney Olympics between Japanese finalists and finalists from the other nations. The data collated by the B~omechanicsD epartment of the Australian lnstitute of Sport was used for this purpose. Swimming events were divided into four phases and the time taken to perform each phase was measured for 48 finalists. Although three Japanese swimmer performances were superior in the free swimming phase, their placing did not reflect this because of inferior performances in the start and turn. In contrast, the opposite situation arose with three other Japanese swimmers. These results suggest that not only the free swimming phase but also the starting and turning phases are important in determining race results in 100 m swimming events in international competition
Formation of Deeply Bound Kaonic Atoms in (K^-,N) Reactions
We study theoretically the (K^-,N) reactions for the formation of the deeply
bound kaonic atoms, which were predicted to be quasi--stable with narrow
widths, using the Green function method. We consider various cases with
different target nuclei and energies systematically and find the clear signals
in the theoretical spectra for all cases considered in this article. The
signals show very interesting structures, such as the instead
of the resonance peak. We discuss the origins of the interesting structures and
possibilities to get new information on the existence of the kaonic nuclei from
the spectra of the atomic state formations.Comment: 11 pages, 9 figure
Detection of the linear radical HC4N in IRC+10216
We report the detection of the linear radical HC4N in the C-rich envelope of
IRC+10216. After HCCN, HC4N is the second member of the allenic chain family
HC_(2n)N observed in space. The column density of HC4N is found to be 1.5
10**12 cm**(-2). The abundance ratio HC2N/HC4N is 9, a factor of two larger
than the decrement observed for the cyanopolyynes HC$_(2n+1)N/HC_(2n+3)N.
Linear HC_4N has a 3-Sigma electronic ground state and is one of the 3
low-energy isomeric forms of this molecule. We have searched for the bent and
ringed HC4N isomers, but could only derive an upper limit to their column
densities of about 3 10**(12) cm**(-2).Comment: Preprint of 10 page
Two dimensionality in quasi one-dimensional cobalt oxides
By means of muon spin rotation and relaxation (SR) techniques, we have
investigated the magnetism of quasi one-dimensional (1D) cobalt oxides
CoO (=Ca, Sr and Ba, =1, 2, 3, 5 and
), in which the 1D CoO chain is surrounded by six equally spaced
chains forming a triangular lattice in the -plane, using polycrystalline
samples, from room temperature down to 1.8 K. For the compounds with =1 - 5,
transverse field SR experiments showed the existence of a magnetic
transition below 100 K. The onset temperature of the transition () was found to decrease with ; from 100 K for =1 to 60 K for
=5. A damped muon spin oscillation was observed only in the sample with
=1 (CaCoO), whereas only a fast relaxation obtained even at 1.8
K in the other three samples. In combination with the results of susceptibility
measurements, this indicates that a two-dimensional short-range
antiferromagnetic (AF) order appears below for all
compounds with =1 - 5; but quasi-static long-range AF order formed only in
CaCoO, below 25 K. For BaCoO (=), as decreased
from 300 K, 1D ferromagnetic (F) order appeared below 53 K, and a sharp 2D AF
transition occurred at 15 K.Comment: 12 pages, 14 figures, and 2 table
Inter- to Intra-Layer Resistivity Anisotropy of NdFeAs(O,H) with Various Hydrogen Concentrations
With molecular beam epitaxy and topotactic chemical reaction, we prepared
NdFeAs(O,H) epitaxial thin films with various hydrogen concentrations on
5{\deg} vicinal cut MgO substrates. By measuring the resistivities along the
longitudinal and transversal directions, the ab plane and the c axis
resistivities (\{rho}_ab and \{rho}_c) were obtained. The resistivity
anisotropy {\gamma}_\{rho}=\{rho}_c \ \{rho}_ab of NdFeAs(O,H) with various
hydrogen concentrations was compared with that of NdFeAs(O,F). At the H
concentrations which led to superconducting transition temperatures Tc over 40
K, {\gamma}_\r{ho} recorded ~100-150 at 50 K. On the other hand, a low
{\gamma}_\{rho} value of 9 was observed with the mostly doped sample. The
exponent \{beta} of the ab plane resistivity obtained by fitting a power law
expression \{rho}_{ab}(T)=\{rho}_0+AT^\{beta} to the data was close to unity
down to low temperature in the vicinity where the second antiferromagnetic
phase locates, which may be related to the quantum critical point discussed at
the over-doped side of the phase diagram.Comment: Appeared in Physical. Rev. Material
Global Star Formation Rates in Disk Galaxies and Circumnuclear Starbursts from Cloud Collisions
We invoke star formation triggered by cloud-cloud collisions to explain
global star formation rates of disk galaxies and circumnuclear starbursts.
Previous theories based on the growth rate of gravitational perturbations
ignore the dynamically important presence of magnetic fields. Theories based on
triggering by spiral density waves fail to explain star formation in systems
without such waves. Furthermore, observations suggest gas and stellar disk
instabilities are decoupled. Following Gammie, Ostriker & Jog (1991), the cloud
collision rate is set by the shear velocity of encounters with initial impact
parameters of a few tidal radii, due to differential rotation in the disk.
This, together with the effective confinement of cloud orbits to a two
dimensional plane, enhances the collision rate above that for particles in a
three dimensional box. We predict Sigma_{SFR}(R) proportional to Sigma_{gas}
Omega (1-0.7 beta). For constant circular velocity (beta = 0), this is in
agreement with recent observations (Kennicutt 1998). We predict a B-band
Tully-Fisher relation: L_{B} proportional to v_{circ}^{7/3}, also consistent
with observations. As additional tests, we predict enhanced star formation in
regions with relatively high shear rates, and lower star formation efficiencies
in clouds of higher mass.Comment: 27 pages including 3 figures and 2 tables. Accepted to ApJ. Expanded
statistical analysis of cloud SF efficiency test. Stylistic changes. Data for
figures available electronically at
http://astro.berkeley.edu/~jt/disksfr.htm
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