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91.
The expansion of Personal Watercraft (PWC) usage around the UK presents unique challenges to organisations responsible for managing coastal areas. This study examines the role of PWC clubs in effecting better management of the sport. Questionnaires and personal interviews with both PWC operators and local authorities were used to gain information on the current UK situation. Within the sample group 73% of participants were also PWC club members. The study suggests changing patterns of PWC usage in the UK, based on the increasing influence of PWC clubs. Coastal managers should be aware of the potential of clubs in conflict resolution. 相似文献
92.
Takuya Fujiyoshi Craig H. Smith Toby J. T. Moore David K. Aitken Patrick F. Roche & Dale E. Quinn 《Monthly notices of the Royal Astronomical Society》1998,296(2):225-230
We present high spatial resolution (∼0.8 arcsec) diffraction-limited 12.8-μm Ne ii fine-structure emission line and 12.5-μm continuum images of the bright southern compact H ii region G333.6–0.2, taken with the mid-infrared imaging polarimeter NIMPOL. The two images show remarkably similar, compact, yet asymmetric, flux distributions. The [Ne ii ] image shows a complex structure near the ionizing source(s) which we interpret in terms of the ionization structure of the H ii region. It is found that G333.6–0.2 is more likely to be excited by a cluster of O and B stars than by a single star. 相似文献
93.
J. S. Clark I. A. Steele M. J. Coe & P. Roche 《Monthly notices of the Royal Astronomical Society》1998,297(3):657-666
We present infrared spectroscopy of the Be/X-ray binary HDE 245770/A0535+26 obtained over the period 1992–1995. The spectra show significant variability, reflecting changes in the circumstellar environment during this time. A reduction in the flux observed in the Paschen series lines between 1993 December and 1994 September correlates with a similar reduction in both the strength of Hα and the optical continuum emission, which can be attributed to a reduction in the emission measure of the disc. A turnover between optically thin and thick emission is seen for both Paschen and Brackett series lines, and allows an estimate of the disc density as ∼1012 cm−3 . Echelle spectroscopy reveals strong similarities between the He I 1.008, 2.058 μm, Hα and Paschen series line profiles, suggesting their formation in a similar (and asymmetric) region of the disc. In contrast, the line profile of He I 6678 Å indicates that it is formed at smaller radii than the other transitions. 相似文献
94.
David K. Aitken Craig H. Smith Toby J. T. Moore & Patrick F. Roche 《Monthly notices of the Royal Astronomical Society》1998,299(3):743-752
Thermal emission from magnetically aligned dust grains produces the observed mid-infrared polarization in the northern arm and east–west bar of SgrA West; recent arcsecond-resolution imaging polarimetry at 12.5 μm of these ionized filaments is presented, which confirms and extends previous studies. A lower limit ∼2 mG is found for the magnetic field in the northern arm and the IRS16 complex appears to be displaced from the northern arm by ∼ 0.15 pc along the line of sight. It is shown that the physical conditions in the ionized filaments of the central parsec lead to a very uniform grain alignment that is directed along the local magnetic field. The position angle of polarized emission will then be at right angles to the projection of the field direction on the plane of the sky and its amplitude a measure of the component of field along the line of sight; this makes possible a partial reconstruction of the field in three dimensions. We present the first application of the use of polarimetry in this way. This partial reconstruction is compared with the H92α observations of Roberts et al. and the implications are that the northern arm and east–west bar do not define either an orbital path or a spiral arm but rather represent a tidally stretched structure in free fall about SgrA★ with significant deviations from a single plane, and most likely represent the inner ionized rim of a more extended neutral cloud. 相似文献
95.
Emile Biemont 《Solar physics》1975,44(2):269-273
Oscillator strengths are calculated by the STF method for selected transitions of Mn i. The results, applied to the analysis of solar spectra, support the ‘high’ solar photospheric abundance of manganese recently obtained on the basis of experimental gf-values. 相似文献
96.
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99.
The tsunami of 26th December 2004 severely affected Yemen’s Socotra Island with a death at a distance of 4,600 km from the
epicenter of the Magnitude 9.0 earthquake. Yemen allowed a detailed assessment of the far-field impact of a tsunami in the
main propagation direction. The UNESCO mission surveyed 12 impacted towns on the north and south shores covering from the
east to the west tip of Socotra. The international team members were on the ground in Yemen from 11 to 19 October 2006. The
team measured tsunami run-up heights and inundation distances based on the location of watermarks on buildings and eyewitness
accounts. Maximum run-up heights were typically on the order of 2–6 m. Each measurement was located by means of global positioning
systems (GPS) and photographed. Numerous eyewitness interviews were recorded on video. The tsunami impact on Socotra is compared
with other locations along the shores of the Indian Ocean. 相似文献
100.