149,255 research outputs found
Radar And Visual Observations Of Autumnal (Southward) Shorebird Migration On Guam
Several species of shorebirds migrate between eastern Asia and the southern Pacific islands, Australia, and New Zealand. Observations made from Guam (13°25′N, 144°45′E) during autumn 1983 indicate that a significant number of birds take a direct route over the western Pacific Ocean. Radar observations and ground counts of migrants on Guam showed two periods of autumnal migratory activity. The first, largely adult birds, was in August and September. The second, largely juveniles, was in late September and October. Radar indicated that large numbers of birds passed over the island to the south with no evidence of compensation for drift by the easterly winds. Comparison of radar and ground observations on Guam showed that only a small subset of migrants stop on the island, suggesting that some species may make nonstop flights between eastern Asia and the South Pacific
Coping with a changing world: the UK Open University approach to teaching ICT
The rapid pace of change in the ICT field has affected all HE providers, but for the UK Open University (UKOU), used to print-based courses lasting eight years or more, it has been a particular challenge. This paper will present some of the ways the UKOU has been coping with this problem by discussing the design of three courses, the first developed almost a decade ago. All three are distance learning courses that are either core or optional in a variety of bachelors' degrees, including the BSc programmes in: Information and Communication Technology; IT and Computing; and Technology; as well as the BEng (Hons) engineering programme.
The first course, Information and Communication Technology: people and interactions is a level 2 (second year undergraduate) course first presented in 2002. It is predominately a print-based course with an eight year lifetime. The second course Networked Living: exploring information and communication technologies is a level 1 (first year undergraduate) course first presented some three-and-a-half years later in 2005. It is expected to have a course life of five years, and uses a mix of print-based (60%) and computer-based (40%) material. Both these courses use assignments as key tools for annual updating.
The third course, Keeping ahead in ICT is aimed primarily at equipping students with advanced information searching and evaluation skills that will serve them well in professional life, and is presented at level 3 (final year undergraduate). It was first presented in 2007 and has an expected course life of 8 years. It uses much less print than in most OU courses, and has a greater reliance on third-party resources such as newspaper, conference and journal articles, websites, and other electronic resources. Some elements in each block are designed to change from year to year, in order to retain currency.
Finally, the paper will look forward to the development of a new level 2 course with an expected first presentation in 2010, drawing out the lessons learned about course updating, and predicting the approach that the course team may tak
Radar studies of bird migration
Observations of bird migration with NASA radars were made at Wallops Island, Va. Simultaneous observations were made at a number of radar sites in the North Atlantic Ocean in an effort to discover what happened to those birds that were observed leaving the coast of North America headed toward Bermuda, the Caribbean and South America. Transatlantic migration, utilizing observations from a large number of radars is discussed. Detailed studies of bird movements at Wallops Island are presented
Bird Migration Through A Mountain Pass Studied With High Resolution Radar, Ceilometers, And Census
Autumnal migration was studied with high-resolution radar, ceilometer, and daily census in the area of Franconia Notch, a major pass in the northern Appalachian Mountains. Under synoptic conditions favorable for migration, broadfront movements of migrants toward the south passed over the mountains, often above a temperature inversion. Birds at lower elevations appeared to be influenced by local topography. Birds moving southwest were concentrated along the face of the mountain range. Birds appeared to deviate their flights to follow local topography through the pass. Specific migratory behavior was not associated with species or species groups. Under synoptic conditions unfavorable for southward migration, multimodal movements probably associated with local flights were as dense as the southward migrations described above. Avian migrants reacting to local terrain may result in concentrations of migrants over ridge summits or other topographic features
Direct observation of voids in the vacancy excess region of ion bombarded silicon
The results reported in this letter indicate that the spatial separation of the vacancy and interstitial excesses which result from ion bombardment gives rise to stable voids upon annealing at 850 °C even for implants where the projected ion range is only of the order of a few thousand Ångstrom. Such voids have been observed directly by transmission electron microscopy. Furthermore, in cases where both voids and interstitial-based defects are present at different depths, it is found that Au has a strong preference for decorating void surfaces and hence Au can, indeed, be used as a selective detector of open volume defects in Si.One of the authors ~J.W.-L.!
acknowledges the Australian Research Council for financial
support
Three-dimensional boundary layers approaching separation
The theory of semi-similar solutions of the laminar boundary layer equations is applied to several flows in which the boundary layer approaches a three-dimensional separation line. The solutions obtained are used to deduce the nature of three-dimensional separation. It is shown that in these cases separation is of the "ordinary" type. A solution is also presented for a case in which a vortex is embedded within the three-dimensional boundary layer
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