354,645 research outputs found
New AMS (14)C dates from the early Upper Paleolithic sequence of Raqefet Cave, Mount Carmel, Israel
Raqefet Cave (35°04'21"N, 32°39'17"W) is situated in the southeastern side of Mount Carmel in Israel (Figure 1) on the left bank of wadi Raqefet (230 m asl), ~50 m above the wadi bed. It is 50 m long with an area of ~500 m2 (Figure 2). Eric Higgs of Cambridge University and Tamar Noy of the Israel Museum conducted excavations at the site between 1970 and 1972 (Higgs et al. 1975). New excavations at the cave began in 2004 (Lengyel et al. 2005)
Mapping forests in monsoon Asia with ALOS PALSAR 50-m mosaic images and MODIS imagery in 2010.
Extensive forest changes have occurred in monsoon Asia, substantially affecting climate, carbon cycle and biodiversity. Accurate forest cover maps at fine spatial resolutions are required to qualify and quantify these effects. In this study, an algorithm was developed to map forests in 2010, with the use of structure and biomass information from the Advanced Land Observation System (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) mosaic dataset and the phenological information from MODerate Resolution Imaging Spectroradiometer (MOD13Q1 and MOD09A1) products. Our forest map (PALSARMOD50 m F/NF) was assessed through randomly selected ground truth samples from high spatial resolution images and had an overall accuracy of 95%. Total area of forests in monsoon Asia in 2010 was estimated to be ~6.3 × 10(6 )km(2). The distribution of evergreen and deciduous forests agreed reasonably well with the median Normalized Difference Vegetation Index (NDVI) in winter. PALSARMOD50 m F/NF map showed good spatial and areal agreements with selected forest maps generated by the Japan Aerospace Exploration Agency (JAXA F/NF), European Space Agency (ESA F/NF), Boston University (MCD12Q1 F/NF), Food and Agricultural Organization (FAO FRA), and University of Maryland (Landsat forests), but relatively large differences and uncertainties in tropical forests and evergreen and deciduous forests
Some current measurements in the Sargasso Sea
Also published as: Deep-Sea Research 12 (1965): 805-814Long-term current measurements at depths of 50 and 100m obtained with Richardson current meters at two deep-water moorings south of Bermuda are reported. The records are dominated by anticyclonic rotations which appear and degenerate, possibly in response to the passage of storms. Spectral analysis of the records indicates that this motion has a period of 24 hours at a depth of 50 m, and 25·3 hours at a depth of 100m. No explanation is given to account for this difference in period over a 50-m separation. Both records indicate the existence of semidiurnal tidal motion. The long-term motions at both depths indicate a systematic change in the net direction of flow over a three-month period.The Office of Naval Research under Contract Nonr-2196(00) NR 083-004
Genomic and proteomic profiling of responses to toxic metals in human lung cells.
Examining global effects of toxic metals on gene expression can be useful for elucidating patterns of biological response, discovering underlying mechanisms of toxicity, and identifying candidate metal-specific genetic markers of exposure and response. Using a 1,200 gene nylon array, we examined changes in gene expression following low-dose, acute exposures of cadmium, chromium, arsenic, nickel, or mitomycin C (MMC) in BEAS-2B human bronchial epithelial cells. Total RNA was isolated from cells exposed to 3 M Cd(II) (as cadmium chloride), 10 M Cr(VI) (as sodium dichromate), 3 g/cm2 Ni(II) (as nickel subsulfide), 5 M or 50 M As(III) (as sodium arsenite), or 1 M MMC for 4 hr. Expression changes were verified at the protein level for several genes. Only a small subset of genes was differentially expressed in response to each agent: Cd, Cr, Ni, As (5 M), As (50 M), and MMC each differentially altered the expression of 25, 44, 31, 110, 65, and 16 individual genes, respectively. Few genes were commonly expressed among the various treatments. Only one gene was altered in response to all four metals (hsp90), and no gene overlapped among all five treatments. We also compared low-dose (5 M, noncytotoxic) and high-dose (50 M, cytotoxic) arsenic treatments, which surprisingly, affected expression of almost completely nonoverlapping subsets of genes, suggesting a threshold switch from a survival-based biological response at low doses to a death response at high doses
High Altitude test of RPCs for the ARGO-YBJ experiment
A 50 m**2 RPC carpet was operated at the YangBaJing Cosmic Ray Laboratory
(Tibet) located 4300 m a.s.l. The performance of RPCs in detecting Extensive
Air Showers was studied. Efficiency and time resolution measurements at the
pressure and temperature conditions typical of high mountain laboratories, are
reported.Comment: 16 pages, 10 figures, submitted to Nucl. Instr. Met
Dispersal of Calluna vulgaris(L.) Hull. seeds on a severly burnt upland moorland
From natural and manipulated experiments at 460 m a.s.l., traps were used to record the dispersal range of
Calluna vulgaris seeds on an unvegetated post-wildfire site. Seeds were trapped to 50 m from source,
although most (73%) were deposited within one metre of the parent plant. C. vulgaris seeds were not
dispersed as far in these experiments as recorded in previous workers’ experiments on lowland grassland
Characteristics and dynamics of surfzone transverse finger bars
Patches of transverse finger bars have been identified in the surf zone of Noordwijk
beach (Netherlands). They consisted of three to nine elongated accumulations of sand
attached to the low-tide shoreline. The bars extended up to 50 m into the inner surf zone,
had an oblique orientation with respect to the shore-normal, and were quasiregularly
spaced in the alongshore direction.Postprint (published version
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FT-IR microanalysis of mineral separates from primitive meteorites: techniques, problems and solutions
From the Introduction: We compared several methods of infrared micro spectroscopy using an FT-IR microscope and workbench. This is part of a project to assemble a database of infrared and optical spectra from mineral separates from meteorites, for comparison with astronomical data. Since we usually have to work with small amounts of material (original grain sizes often <50 m), special sample preparation and analytical procedures
have to be applied
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