The NAIAD experiment for WIMP searches at Boulby mine and recent results     

B. Ahmed  G. J. Alner  H. Araujo  J. C. Barton  A. Bewick  M. J. Carson  D. Davidge  J. V. Dawson  T. Gamble  S. P. Hart  R. Hollingworth  A. S. Howard  W. G. Jones  M. K. Joshi  V. A. Kudryavtsev  T. B. Lawson  V. Lebedenko  M. J. Lehner  J. D. Lewin  P. K. Lightfoot  I. Liubarsky  R. Lüscher  J. E. McMillan  B. Morgan  G. Nicklin  S. M. Paling  R. M. Preece  J. J. Quenby  J. W. Roberts  M. Robinson  N. J. T. Smith  P. F. Smith  N. J. C. Spooner  T. J. Sumner  D. R. Tovey 《Astroparticle Physics》2003,19(6):691-702

The NAIAD experiment (NaI Advanced Detector) for weakly interacting massive particle (WIMP) dark matter searches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulated NaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6 kg × year exposure) have been used to set upper limits on the WIMP–nucleon spin-independent and WIMP–proton spin-dependent cross-sections. Pulse shape analysis has been applied to discriminate between nuclear recoils, as may be caused by WIMP interactions, and electron recoils due to gamma background. Various calibrations of crystals are presented.  相似文献   

Neutron background in large-scale xenon detectors for dark matter searches     

M. J. Carson  J. C. Davies  E. Daw  R. J. Hollingworth  V. A. Kudryavtsev  T. B. Lawson  P. K. Lightfoot  J. E. McMillan  B. Morgan  S. M. Paling  M. Robinson  N. J. C. Spooner  D. R. Tovey 《Astroparticle Physics》2004,21(6):667-687

Simulations of the neutron background for future large-scale particle dark matter detectors are presented. Neutrons were generated in rock and detector elements via spontaneous fission and (α,n) reactions, and by cosmic-ray muons. The simulation techniques and results are discussed in the context of the expected sensitivity of a generic liquid xenon dark matter detector. Methods of neutron background suppression are investigated. A sensitivity of 10⁻⁹–10⁻¹⁰ pb to WIMP-nucleon interactions can be achieved by a tonne-scale detector.  相似文献   

On the capsize performance of a discus buoy in deep sea breakers     

R.M. Carson   《Ocean Engineering》1982,9(5):501-514

The mode of capsize of a discus buoy in breaking waves is discussed. The results of model tests are given; these show that a judicious choice of mooring design can substantially reduce the chance of capsize. A comparison is made with the performance of the buoy on station.  相似文献   

Quaternary landscape change and modern process in western North America     

Jeffrey S. Munroe  Guest editor  Benjamin J.C. Laabs  Guest editor  Eric C. Carson  Guest editor 《Geomorphology》2006,75(3-4):281

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Local provenance in rehabilitation of degraded landscapes: a case study from the Hawkesbury–Nepean catchment, Australia     

Shelley Burgin  J Carson  B Maheshwari 《Area》2005,37(3):324-331

Throughout Australia thousands of volunteers are engaged in Landcare projects that should help rehabilitate degraded landscapes. Many of these projects involve tree planting, but their seed is not necessarily of local provenance. Based on a survey of 85 Landcare groups working in the Hawkesbury–Nepean catchment, data were collected about Landcare groups' knowledge of their seed source, understanding of local provenance and the ecosystem in which they were planting trees and the source of funding for their projects. The findings from the study indicate that about one in five (21%) of the groups surveyed that introduced plant material were not aware of local provenance issues. Indirect indications were that a large number of Landcare groups state-wide may be doing more harm than good to the landscape while trying to rehabilitate it. The data also showed that one in seven (13%) of the groups funded by the Australian Government through the Natural Heritage Trust (NHT) had limited awareness of local provenance issues. With millions of dollars being spent on 'works on the ground', it would be prudent to allocate some funds to document and monitor current Landcare activities, so that the environmental outcomes can be quantified and more effective Landcare policies can be developed in the future.  相似文献   

Coastal sea level changes,observed and projected during the 20th and 21st century     

M. Carson  A. Köhl  D. Stammer  A. B. A. Slangen  C. A. Katsman  R. S. W. van de Wal  J. Church  N. White 《Climatic change》2016,134(1-2):269-281

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Geocomputation: a practical primer,by Chris Brunsdon and Alex Singleton,London, SAGE Publications, 2015, 392 pp., US$52.00, ISBN 9781446272930 (paperback), ISBN 9781446272923 (hardcover)     

Carson J. Q. Farmer 《International journal of geographical information science》2016,30(4):819-821

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DEVELOPMENT OF AN INEXPENSIVE IMAGE SPACE PLOTTER     

W. W. Carson 《The Photogrammetric Record》1985,11(65):525-541

This paper discusses an inexpensive, analytical system designed for a forestry application of photogrammetry. It is presented in two parts. Part I describes an image space plotter that was built in New Zealand and is operating there. The system uses a digitising table to collect left-hand photograph co-ordinates. an encoded micrometer bar to measure × parallax and a mirror stereoscope for viewing photographs. The mathematical, formulation is based on simplifications first suggested by E. H. Thompson. Good accuracy in ground heights can be achieved by the system, but only poor accuracy in planimetric co-ordinates. The cause of poor planimetric accuracy is investigated in Part II. Two error sources are apparent: the simplified analytical theory and systematic errors from the digitising table. Part II also investigates the relationship between random errors in image co-ordinate measurements and system accuracy.  相似文献   

Genetical Processes of Evolution on High Oceanic Islands     

H. L. Carson 《GeoJournal》1983,7(6):543-547

The Hawaiian Drosophila project has been in progress for 20 years. Recently, emphasis has been placed on studies of genetic variability in natural populations. The data generated are of extraordinary interest for understanding the genetic basis of evolution. The findings are relevant not only to islands forms but also to species in continental ecosystems. Chromosomal, electrophoretic and morphometric studies of specimens from local populations (demes) of island species have shown them generally to be as rich in genetic variability as demes of widespread continental species. The main difference between continntal and insular species is that the latter have smaller total population sizes insular species have fewer demes. On high volcanic islands, the most striking mode of speciation is through one or a few inter-island or inter-volcano founders. The case of Drosophila silvestris from the island of Hawaii is presented. Enforced isolation appears to foster genetic divergence. An unexpected results is that the founder effect does not drasticaly reduce genetic variablity. Rather, it appears to induce a shift in the polygenic heterozygous balances that underlie the genetics of quantitative characters, especially those dealing with mating behavior.In view of these findings, the well-known exuberance of novel adaptations and species observed on isolated oceanic islands is understandable.  相似文献   

Genetic change after colonization     

Hampton L. Carson Dr. 《GeoJournal》1992,28(2):297-302

Consideration is given to the case of a daughter population of a sexual species that becomes successfully established in an area previously lacking that species, as has occurred recently in the Krakataus. If the new area is isolated geographically and if the number of founder individuals is small, conventional wisdom foresees a reduction of genetic variability within the colony. This might obstruct genetic adjustment to new conditions. Recent studies of the genetics of such bottlenecked populations, however, show that, in some instances, genetic variability for quantitative traits may actually increase rather than decrease after a bottleneck event. Whereas loss of some quasi-neutral biochemical alleles may occur, the quantitative polygenic balances on which adaptation depends can be carried through the bottleneck into the new population. Novel phenotypes may result from natural selection during the generations that immediately follow the bottleneck. Growing shield volcanoes in particular show rapid turnover of their surfaces such that organisms surviving there must continually recolonize or become extinct. Such species, existing as metapopulations, should be prone to bottleneck effects that produce genetic shifts. Examples are given from Drosophila silvestris on the island of Hawaii. The relevance of such genetic shifts to population structure and evolutionary change in populations is discussed, emphasizing the probable role of metapopulation structure.  相似文献