IGU Commission on Health and Developement     

Helen Roy  Eric Wajnberg 《GeoJournal》1989,18(4):451-451

The International Geographical Union Reports

IGU Commission on Population Geography  相似文献   

Focal mechanisms of large earthquakes in the South Island of New Zealand: implications for the accommodation of Pacific-Australia plate motion     

Helen Anderson  Terry Webb  James Jackson 《Geophysical Journal International》1993,115(3):1032-1054

  相似文献   

Ocean-atmosphere CO2 exchange: An accessible lab simulation for considering biological effects     

David A. Noever  Helen C. Matsos  Raymond J. Cronise  Loren L. Looger  Rachna A. Relwani  Vladimir I. Nikora 《Climatic change》1994,27(3):299-320

Phytoplankton is considered a key component mediating the ocean-atmospheric exchange of carbon dioxide and oxygen. Lab simulations which model biological responses to atmospheric change are difficult to translate into natural settings owing in part to the vertical migration of phytoplankton. In the sea this vertical migration acts to regulate actual carbon dioxide consumption. To capture some critical properties of this vertical material transfer, we monitored the effects of atmospheric CO₂ on dense suspensions of bioconvecting microorganisms. Bioconvection refers to the spontaneous patterns of circulation which arise among such upwardly swimming cells as alga, protozoa, zoospore and large bacteria. Gravity, phototaxis and chemotaxis have all been implicated as affecting pattern-forming ability. The ability of a biologically active suspension to detect atmospheric changes offers a unique method to quantify organism adjustment and vertical migration. With increasing CO₂, bioconvection patterns in alga (P. parva) and protozoa (T. pyriformis) lose their robustness, and surface cell populations retreat from the highest CO₂ regions. Cell movement (both percent motile and mean velocity) generally diminishes. A general program of image analysis yields statistically significant variations in macroscopic migration patterns; both fractal dimension and various crystallographic parameters correlate strongly with carbon dioxide content.  相似文献   

Sociospatial aspects of Australian aboriginal underdevelopment. Empirical evidence from the East kimberley     

Helen Ross  David Drakakis-Smith 《Geoforum》1983,14(3):325-332

Prior to the penetration of the European capitalist economy into central and northern Australia, the Aboriginal mode of production was one of hunting and gathering. Spiritual, economic and social relationships betwen people and land produced a spatial distribution of small bands of people living on their traditional lands. To the incoming white settlers the low population density and type of land use appeared uneconomic. This observation was used as ideological justification for the expropriation and development of the land for commercial pastoralism. This paper discusses the articulation of the Aboriginal and European modes of production in the East Kimberley region of northwest Australia. It argues that the introduced capitalist economy virtually destroyed the Aboriginal means of subsistence, incorporating Aborigines into the new mode of production within various subordinate roles. The exploitation of Aborigines, formerly as labour and now predominantely as consumers, is fundamental to the maintenance of the capitalist mode of production in pastoral areas. The spatial effects of the dominant mode of production have been to centralise Aborigines in locations suited to the various phases of development of the European economy, undermining the traditional Aboriginal social-spatial structure. The centralisation of the Aboriginal population also enhances the opportunities for the further development of the mining industry, which is in direct competition with Aboriginal interests in land. Aboriginal resistance to these spatial tendencies is intense in many quarters, but efforts to return to living on traditional lands and to develop alternative ways of living are hampered by the dominant mode of production.  相似文献   

Miscellaneous information 1989 (Addendum)     

Joseph Arditti  Adisheshappa Nagaraja Rao  Helen Nair 《Bulletin of Volcanology》1993,55(Z1):128

Miscellaneous information 1989 (Addendum)  相似文献   

Manual of planktonic foraminifera: J.A. Postuma. Elsevier,Amsterdam-London-New York, 1971, 420 pp., 1153 illustrations, 3 charts,Dfl. 75.00 (U.S.$ 20.75).     

Helen Tappan 《Sedimentary Geology》1972

  相似文献   

Were Greek temples oriented towards aurorae?     

Ioannis Liritzis  Helen Vassiliou 《Astronomy& Geophysics》2006,47(1):1.14-1.18

Ioannis Liritzis and Helen Vassiliou assess the evidence that the Ancient Greeks saw the aurora borealis, and that it was a rare and special event, strongly enough associated with particular gods to build temples of unusual orientation.  相似文献   

Microbial ecology of the stratified water column of the Black Sea as revealed by a comprehensive biomarker study   总被引：2，自引：0，他引：2  

Stuart G. Wakeham  Rudi Amann  Katherine H. Freeman  Ellen C. Hopmans  Bo Barker Jrgensen  Isabell F. Putnam  Stefan Schouten  Jaap S. Sinninghe Damst  Helen M. Talbot  Dagmar Woebken 《Organic Geochemistry》2007,38(12):2070-2097

The stratified water column of the Black Sea is partitioned into oxic, suboxic, and euxinic zones, each characterized by different biogeochemical processes and by distinct microbial communities. In 2003, we collected particulate matter by large volume in situ filtration at the highest resolution to date for lipid biomarker analysis and bacterioplankton for enumeration of major prokaryotic groups. Abundances of several prokaryotic groups were estimated using CARD-FISH probes specific for Bacteria, Archaea (Crenarchaeota and Euryarchaeota), epsilonproteobacteria (mainly sulfide oxidizers) and sulfate reducing bacteria. We also measured a wide range of bacterial and archaeal lipid biomarkers. Depth distributions of diagnostic biomarkers are matched with zonation of microbial processes, including aerobic bacterial oxidation of methane, oxidation of ammonium by bacteria and archaea, metal reduction, and sulfide oxidation at the chemocline, and bacterial sulfate reduction and anaerobic oxidation of methane by archaea in the anoxic zone. Cell densities for archaea and sulfate reducing bacteria are estimated based on water column biomarker concentrations and compared with CARD-FISH results.  相似文献   

Modeling long-period noise in kinematic GPS applications     

Adrian A. Borsa  Jean-Bernard Minster  Bruce G. Bills  Helen A. Fricker 《Journal of Geodesy》2007,81(2):157-170

We develop and test an algorithm for modeling and removing elevation error in kinematic GPS trajectories in the context of a kinematic GPS survey of the salar de Uyuni, Bolivia. Noise in the kinematic trajectory ranges over 15 cm and is highly autocorrelated, resulting in significant contamination of the topographic signal. We solve for a noise model using crossover differences at trajectory intersections as constraints in a least-squares inversion. Validation of the model using multiple realizations of synthetic/simulated noise shows an average decrease in root-mean-square-error (RMSE) by a factor of four. Applying the model to data from the salar de Uyuni survey, we find that crossover differences drop by a factor of eight (from an RMSE of 5.6 to 0.7 cm), and previously obscured topographic features are revealed in a plan view of the corrected trajectory. We believe that this algorithm can be successfully adapted to other survey methods that employ kinematic GPS for positioning.  相似文献   

Detection of iodine monoxide radicals in the marine boundary layer using laser induced fluorescence spectroscopy     

Lisa K. Whalley  Kate L. Furneaux  Tom Gravestock  Helen M. Atkinson  Catherine S. E. Bale  Trevor Ingham  William J. Bloss  Dwayne E. Heard 《Journal of Atmospheric Chemistry》2007,58(1):19-39

A Laser Induced Fluorescence (LIF) instrument has been developed to detect iodine monoxide (IO) radicals in the atmosphere. An all solid-state Nd:YAG pumped Ti:Sapphire laser operating at approximately 445 nm was used to excite the (2,0) band of the IO A²Π_3/2 ← X²Π_3/2 electronic transition, with off-resonance fluorescence in the (2,5) band detected at 521 nm. The sensitivity of the instrument was determined by calibration. IO (between 10 and 150 pptV) was generated following the 184.9 nm photolysis of N₂O/CF₃I/N₂ mixtures with O₃ actinometry used to determine the photolysis flux. The detection limit was determined to be 0.3 pptV for a 300 s integration period, with an uncertainty of 23% (1σ). The instrument was deployed in August/September 2006 during the RHaMBLe (Reactive Halogens in the Marine Boundary Layer) campaign in Roscoff, France. Located on a small jetty, a few metres from the water’s edge at high tide, the instrument measured significant levels of IO on 11 days, with a maximum of 27.6 ± 3.2 pptV observed on one day (averaged over 10 s) representing the highest IO mixing ratio recorded in the marine boundary layer to date. IO displayed a clear diurnal profile with a maximum at low tide during the daytime. These results represent the first point measurements of IO in the atmosphere by LIF.  相似文献