3,063 research outputs found
ISOPHOT Observations of Narrow-Line Seyfert 1 Galaxies
Broad infrared spectra (7-200 micrometer) of four NLS1 galaxies, obtained
with the imaging photo-polarimeter (ISOPHOT) on board the Infrared Space
Observatory (ISO), are presented. The infrared luminosities and temperatures,
opacities and sizes of the emitting dust components are derived. A comparison
between the observed infrared spectra and the optical emission line fluxes of a
sample of 16 NLS1 galaxies suggests that these objects suffer different degrees
of dust absorption according to the inclination of the line of sight with
respect to the dust distribution.Comment: Contributed talk presented at the Joint MPE,AIP,ESO workshop on
NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also
available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho
The Geography of Non-formal Manifolds
We show that there exist non-formal compact oriented manifolds of dimension
and with first Betti number if and only if and
, or and . Moreover, we present explicit
examples for each one of these cases.Comment: 8 pages, one reference update
Maturation of the Calico Scallop, Argopecten gibbus, Determined by Ovarian Color Changes
Ovarian color was described for the calico scallop, Argopecten gibbus, by sizes and seasons from May 1970 to October 1971 on the Cape Canaveral grounds, Florida. Seven stages of ovarian development were recognized primarily by color and sequence of development and graded from immature to ripe to spent. Scallops as small as 20 mm shell height can be ripe. There were distinct changes in developmental stage by season. Most scallops were ripe from January to May; in August, large scallops were spent or developing and small scallops were immature. Based on seasonal occurrence of ripe and partially spawned scallops, spawning extended primarily from about November to July and was intense from January to May. There was no spawning in August. Variations occurred in the spawning pattern between years
Uniform semiclassical wave function for coherent 2D electron flow
We find a uniform semiclassical (SC) wave function describing coherent
branched flow through a two-dimensional electron gas (2DEG), a phenomenon
recently discovered by direct imaging of the current using scanned probed
microscopy. The formation of branches has been explained by classical
arguments, but the SC simulations necessary to account for the coherence are
made difficult by the proliferation of catastrophes in the phase space. In this
paper, expansion in terms of "replacement manifolds" is used to find a uniform
SC wave function for a cusp singularity. The method is then generalized and
applied to calculate uniform wave functions for a quantum-map model of coherent
flow through a 2DEG. Finally, the quantum-map approximation is dropped and the
method is shown to work for a continuous-time model as well.Comment: 9 pages, 7 figure
Muon spin relaxation study of the magnetism in unilluminated Prussian Blue analogue photomagnets
We present longitudinal field muon spin relaxation (SR) measurements in
the unilluminated state of the photo-sensitive molecular magnetic Co-Fe
Prussian blue analogues MCo[Fe(CN)] HO, where
M=K and Rb with and , respectively. These results are
compared to those obtained in the stoichiometric limit,
Co[Fe(CN)] HO, which is not photo-sensitive. We find
evidence for correlation between the range of magnetic ordering and the value
of in the unilluminated state which can be explained using a site
percolation model.Comment: 7 pages, 12 figure
Effects of Methylene Blue and Polyethelene Glycol on Facial Nerve Axotomy Recovery
poster abstractInjury and disease are common factors affecting peripheral nerves and can lead to loss of function. Recovery time after an injury is slow and not very efficient in humans. Treatment methods involving methylene blue (MB) and polyethylene glycol (PEG) have shown combinational effects in sciatic nerve axotomies. We are using behavior analysis of eye blink reflex and vibrissae orientation and movement as a measurement of rate of functional recovery. We will have treatment groups of both cut and crush rats. For each group we will be testing the effect of PEG/MB or no treatment control groups. The results of these treatment groups are significant to finding treatment options for clinical use
Comparison of multiple approaches to calculate time-varying biological reference points in climate-linked population-dynamics models
Fisheries managers use biological reference points (BRPs) as targets or limits on fishing and biomass to maintain productive levels of fish stock biomass. There are multiple ways to calculate BRPs when biological parameters are time varying. Using summer flounder (Paralichthys dentatus) as a case study, we investigated time-varying approaches in concert with climate-linked population models to understand the impact of environmentally driven variability in natural mortality, recruitment, and size-At-Age on two commonly used BRPs [B0(t) and F35%(t)]. We used the following two approaches to calculate time-varying BRPs: dynamic-BRP and moving-Average-BRP. We quantified the variability and uncertainty of different climate dependencies and estimation approaches, attributed BRP variation to variation in life-history processes, and evaluated how using different approaches impacts estimates of stock status. Results indicate that the dynamic-BRP approach using the climate-linked natural mortality model produced the least variable reference points compared to others calculated. Summer flounder stock status depended on the estimation approach and climate model used. These results emphasize that understanding climate dependencies is important for summer flounder reference points and perhaps other species, and careful consideration is warranted when considering what time-varying approach to use, ideally based upon simulation studies within a proposed set of management procedures
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