84,097 research outputs found
Graptemys oculifera
Number of Pages: 2Integrative BiologyGeological Science
Graptemys
Number of Pages: 3Integrative BiologyGeological Science
Pseudemys alabamensis
Number of Pages: 2Integrative BiologyGeological Science
Modelling the spectral energy distribution of galaxies from the ultraviolet to submillimeter
We present results from a new modelling technique which can account for the
observed optical/NIR - FIR/submm spectral energy distributions (SEDs) of normal
star-forming galaxies in terms of a minimum number of essential parameters
specifying the star-formation history and geometrical distribution of stars and
dust. The model utilises resolved optical/NIR images to constrain the old
stellar population and associated dust, and geometry-sensitive colour
information in the FIR/submm to constrain the spatial distributions of young
stars and associated dust. It is successfully applied to the edge-on spirals
NGC891 and NGC5907. In both cases the young stellar population powers the bulk
of the FIR/sub-mm emission. The model also accounts for the observed surface
brightness distribution and large-scale radial brightness profiles in NGC891 as
determined using the Infrared Space Observatory (ISO) at 170 and 200 mcrions
and at 850 micron using SCUBA.Comment: 20 pages (Latex), Highlight talk at the Joint European and National
Astronomical Meeting JENAM 2001, to be published in Reviews in Modern
Astronomy 15: Five Days of Creation: Astronomy with Large Telescopes from
Ground and Base. Germany : Astronomische Gesellschaft, 200
The strong mixing and the selfdecomposability properties
It is proved that infinitesimal triangular arrays obtained from normalized
partial sums of strongly mixing (but not necessarily stationary) random
sequences, can produce as lilmits only selfdecomposable distributions
Scale-up of electrospray atomization using linear arrays of Taylor cones
Linear arrays of Taylor cones were established on capillary electrode tubes opposite a slotted flat plate counterelectrode to investigate the feasibility of increasing the liquid throughput rate in electrospray atomizers. It was found that individual Taylor cones could be established on each capillary over a wide range of the capillary radius to spacing ratio R/S. The onset potential Vs required to establish the cones varied directly with R/S, but the liquid flow rate per cone and current per cone were nearly independent of R/S for a given overpotential ratio P=V/Vs. Only six working capillaries were used, but the results per cone are applicable to larger arrays of cones since end effects were minimized
Versatile Control System for Automated Single-Molecule Optical Tweezers Investigations
We present a versatile control system to automate single-molecule biophysics experiments. This method combines low-level controls into various functional, user-configurable modules, which can be scripted in a domain-specific instruction language. The ease with which the high-level parameters can be changed accelerates the development of a durable experiment for the perishable single-molecule samples. Once the experimental parameters are tuned, the control system can be used to repeatedly manipulate other single molecules in the same way, which is necessary to accumulate the statistics needed to report results from single-molecule studies. This system has been implemented for an optical tweezers instrument for single-molecule manipulations, with real-time point-by-point feedback at a loop rate of 10-20 kHz
\u3csup\u3e13\u3c/sup\u3eC NMR Analysis of Biologically Produced Pyrene Residues by \u3cem\u3eMycobacterium\u3c/em\u3e sp. KMS in the Presence of Humic Acid
Cultures of the pyrene degrading Mycobacterium sp. KMS were incubated with [4-13C]pyrene or [4,5,9,10-14C]pyrene with and without a soil humic acid standard to characterize the chemical nature of the produced residues and evaluate the potential for bonding reactions with humic acid. Cultures were subjected to a “humic acid/humin” separation at acidic pH, a duplicate separation followed by solvent extraction of the humic acid/humin fraction, and a high pH separation. 13C NMR analysis was conducted on the resulting solid extracts. Results indicated that the activity associated with solid extracts did not depend on pH and that approximately 10% of the added activity was not removed from the solid humic acid/humin fraction by solvent extraction. 13C NMR analysis supported the conclusion that the majority of pyrene metabolites were incorporated into cellular material. Some evidence was found for metabolite reaction with the added humic material, but this did not appear to be a primary fate mechanism
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