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A. Quirrenbach J. Larkin M. Barczys T. Gasaway C. Iserlohe A. Krabbe M. McElwain I. Song J. Weiss S. Wright 《New Astronomy Reviews》2006,49(10-12):639
OSIRIS (OH-Suppressing Infra-Red Integral-field Spectrograph) is a new facility instrument for the Keck Observatory. After seeing first light in February 2005, OSIRIS is currently undergoing commissioning. OSIRIS provides the capability of performing three-dimensional spectroscopy in the near-infrared z, J, H, and K bands at the resolution limit of the Keck II telescope, which is equipped with adaptive optics and a laser guide star. The science case for OSIRIS is summarized, and the instrument and associated data reduction software are described. 相似文献
2.
In this study male largemouth bass (LMB) were exposed to the naturally occurring androgens, dihydrotestosterone (DHT) or 11-ketotestosterone (11-KT) in order to identify genes that are differentially regulated by these steroid hormones. Using subtractive hybridization on livers of fish treated with DHT against vehicle control, many novel LMB genes were cloned. These genes were added to our gene library and arrayed. Six genes were up-regulated and five were down-regulated by both androgens. But, each androgen also regulated specific genes. One gene that was identified as a potential androgen marker was spermidine-spermine-N(1)-acetyltransferase that was up-regulated by both androgens. Determining which genes are responsive to natural androgens will help to identify biochemical pathways that are impacted. 相似文献
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R. I. Acworth W. A. Timms B. F. J. Kelly D. E. Mcgeeney T. J. Ralph Z. T. Larkin 《Australian Journal of Earth Sciences》2013,60(6):657-680
The Liverpool Plains in northern New South Wales contain some of the best agricultural land in Australia and are underlain by extensive smectite clay-dominated soils sourced from weathering the alkali basalts of the Liverpool Ranges. It had been thought that a relatively simple geological model explained the underlying Cenozoic sequence with salt-rich clays of the Narrabri Formation overlying sands and gravel aquifers comprising the Gunnedah Formation. Extensive groundwater modelling based upon this simple conceptualisation has been used in management plans proposed by the mining and agricultural industries. A 31.5 m core has been recovered using minimally disturbed triple-tube coring methods at Cattle Lane (Latitude –31.52° S, Longitude 150.47° E) to resolve uncertainty concerning the aquitard status of the upper layer. Recovered core has been examined and tested to determine grainsize, cation-exchange capacity, X-ray diffraction, X-ray fluorescence and microscopic examination of granular components. These measurements complement surface and borehole geophysical techniques, hydrogeological data and hydrochemical analysis of water samples recovered from a series of specially constructed piezometers adjacent to the cored hole. The sequence overlies a Late Cretaceous channel cut into Permian bedrock at 91 m depth with sands and clays below 31.5 m considered to represent various alluvial fill events mostly occurring since the Early Pliocene. Erosion of Late Eocene alkali basalts on the Liverpool Ranges, with the formation of smectite clays, pedogenic carbonates and with the addition of quartz from both eolian sources and locally derived from adjacent Triassic sandstone hills, provides the great majority of the sediment recovered from the cores. Late Pleistocene (114 ka) to Holocene ages were determined for the core from three optically stimulated luminescence (OSL) measurements on fine sands (13, 23 and 29 m BG). Detailed examination has failed to detect any evidence of a boundary between Narrabri and Gunnedah formations revealing rather a gradual change in dominance of clays and silts over sands and gravels embedded in a clay-rich matrix. This result challenges the conceptualisation used to conduct groundwater modelling on the Liverpool Plains. 相似文献
4.
A Benthic Terrain Classification Scheme for American Samoa 总被引：2，自引：0，他引：2
Emily R. Lundblad Dawn J. Wright Joyce Miller Emily M. Larkin Ronald Rinehart David F. Naar Brian T. Donahue S. Miles Anderson Tim Battista 《Marine Geodesy》2006,29(2):89-111
Coral reef ecosystems, the most varied on earth, continually face destruction from anthropogenic and natural threats. The U.S. Coral Reef Task Force seeks to characterize and map priority coral reef ecosystems in the U.S./Trust Territories by 2009. Building upon NOAA Biogeography shallow-water classifications based on Ikonos imagery, presented here are new methods, based on acoustic data, for classifying benthic terrain below 30 m, around Tutuila, American Samoa. The result is a new classification scheme for American Samoa that extends and improves the NOAA Biogeography scheme, which, although developed for Pacific island nations and territories, is only applicable to a maximum depth of 30 m, due to the limitations of satellite imagery. The scheme may be suitable for developing habitat maps pinpointing high biodiversity around coral reefs throughout the western Pacific. 相似文献
5.
Microbial mats were collected from a variety of sites near hydrocarbon vents along the slope in the northern Gulf of Mexico and, for comparison, from Warm Mineral Springs, Florida, USA. A predominant microorganism in each of the mats was the giant bacterium,Beggiatoa. Diameters of the bacterial filaments ranged from about 6 µm to approximately 200 µm. The latter organisms are the largest prokaryotic organisms yet found. All filaments over about 10 µm in diameter contained a large central vacuole, producing a cell with the cytoplasm as a cylindrical tube underlying the cytoplasmic membrane. Sulfur globules were confined to this peripheral layer. Push cores often contained pyrite tubules whose appearance is suggestive of aBeggiatoa origin. Determinations of
13C inBeggiatoa mats from vents along the Louisiana slope yielded values in the range of –26.6 to –27.9 (PDB), suggesting an unusually high degree of isotope fractionation (–24.9) relative to the carbon source in the ambient seawater, which is typical of sulfur-oxidizing chemoautotrophs. The presence of SO (elemental sulfur) within cells ofBeggiatoa resulting from oxidation of H2S supports the importance of bacterial sulfate reduction processes in the underlying vents for the sustenance of theBeggiatoa mats. 相似文献
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Marc S. Humphries Claudia R. Benitez-Nelson Michael Bizimis Timothy J. Ralph Zacchary T. Larkin Terence S. McCarthy 《地球表面变化过程与地形》2020,45(8):1705-1716
Dust plays a globally important role in supplying biologically essential elements to landscapes underlain by nutrient-poor substrates. Here we show that dust may play a significant role in sustaining productivity in the vast wetlands of the Okavango Delta in southern Africa, one of the world's richest biodiversity hotspots. Dust accumulates preferentially on tree-covered islands in the seasonal swamps of the Delta, creating pockets of fine-grained, nutrient-rich material within the semi-arid landscape of the Kalahari Desert. Strontium and neodymium isotopes reveal that this dust likely originates predominantly from the Makgadikgadi salt pans, located 300 km away, and contributes 10–80% of the fine-grained material present in Okavango island soils. Surface material sourced from the Makgadikgadi Pans contains relatively high amounts of bioavailable phosphorus and iron, potentially influencing Okavango Delta biological productivity. We propose that long-term ecosystem productivity and nutrient availability in the Okavango may be strongly mediated by regional dust inputs. Understanding the influence of dust deposition on nutrient loads and biogeochemical cycling is thus critical for predicting the response of the Okavango Delta to future changes in climate. We suggest that dust inputs may play a significant role in the supply of nutrients to other large, global wetland systems located in dryland environments. © 2020 John Wiley & Sons, Ltd 相似文献
8.
Near-complete collagen (I) sequences are proposed for elephantid and mammutid taxa, based upon available African elephant genomic data and supported with LC-MALDI-MS/MS and LC-ESI-MS/MS analyses of collagen digests from proboscidean bone. Collagen sequence coverage was investigated from several specimens of two extinct mammoths (Mammuthus trogontherii and Mammuthus primigenius), the extinct American mastodon (Mammut americanum), the extinct straight-tusked elephant (Elephas (Palaeoloxodon) antiquus) and extant Asian (Elephas maximus) and African (Loxodonta africana) elephants and compared between the two ionization techniques used. Two suspected mammoth fossils from the British Middle Pleistocene (Cromerian) deposits of the West Runton Forest Bed were analysed to investigate the potential use of peptide mass spectrometry for fossil identification. Despite the age of the fossils, sufficient peptides were obtained to identify these as elephantid, and sufficient sequence variation to discriminate elephantid and mammutid collagen (I). In-depth LC-MS analyses further failed to identify a peptide that could be used to reliably distinguish between the three genera of elephantids (Elephas, Loxodonta and Mammuthus), an observation consistent with predicted amino acid substitution rates between these species. 相似文献
9.
This article provides information on those population education materials and services which are available from the Population Reference Bureau (PRB) and explores their usefulness in secondary school and college environments. PRB data sheets are a most useful source of information. Demographic and socioeconomic information (birth and death rates, natural increase, population doubling times, projections for the year 2000, life expectancies, per capita gross national product, etc.) are included. The World's Women Data Sheet is a special publication issued to mark the midway point of the UN Decade for Women. 161 countries are included with information on demographic, health, employment, and educational status of women. There is a nominal cost for these data sheets. To help students learn about population dynamics and world patterns of population, mapping exercises can be developed. The Population Bulletin is published 6 times/year and each issue concentrates on specific aspects of population. The 28 bulletins which have been published since January 1976 are listed. The PRB Chart Series is a multicolor graphic presentation of topical issues in population and development trends worldwide. A total of 26 charts in 4 series have been produced and cover such topics as world population growth, urbanization, world energy consumption, age structure in the U.S., and adolescent pregnancy in the U.S. This material is best used with high school students. A monthly international population news magazine called Intercom is desinged to inform about worldwide trends and activities in population and family planning. It is published in both English and Spanish and is a useful source of current information in capsulized form. For population educators there is the bimonthly newsletter Interchange. PRB's teaching-learning modules are valuable publications for teachers. Thus far there are 9, each of which is a self-contained unit with classroom activities for junior high to college students. Each one outlines a problem and then presents methods which can stimulate discussion and provoke interest. 2 special publications on special interest topics (Population Handbook; Population Education: Sources and Resources) are described. PRB may well be the best single source of population education materials which will hopefully be used and incorporated into teaching. 相似文献
10.
Larkin P Folmar LC Hemmer MJ Poston AJ Lee HS Denslow ND 《Marine environmental research》2002,54(3-5):395-399
A variety of anthropogenic chemicals are capable of binding to the estrogen receptor of vertebrate species. Binding of these compounds can interfere with homeostasis by disrupting normal gene expression patterns. The purpose of this study was to investigate the feasibility of applying array technology as a monitoring tool for detecting the presence and distribution of estrogenic compounds in coastal habitats using sheepshead minnows as our model. cDNA clones that were isolated from differential display, including vitellogenin alpha and beta, vitelline envelope protein (ZP2), and transferrin, among others, were spotted on the macroarray. The results of these experiments demonstrate a characteristic expression pattern of estrogen responsive genes in sheepshead minnows exposed to 17 beta-estradiol (E2). 相似文献