8,528 research outputs found
The Coase Theorem, or the Coasian Lens? An Application to GMO Regulation
We develop a property rights-transaction costs framework called the Coasian Lens (CL). We argue the CL captures Coase's seminal ideas (1937; 1960) more closely than the Coase Theorem. We use the CL to examine how regulation of genetically modified organisms (GMOs) may affect contract structures in the global agri-food chain.Research and Development/Tech Change/Emerging Technologies,
VEXAR PLASTIC NETTING TO REDUCE POCKET GOPHER DEPREDATION OF CONIFER SEEDLINGS
In 1976, we began a comprehensive evaluation of Vexar seedling protectors as a means of reducing damage to conifer seedlings by pocket gophers (Thomomys spp.). The protectors are cylinders of plastic netting that gradually decompose in sunlight. The evaluation is being conducted on four national forests in three western states. Three conifer species, lodgepole pine (Pinus contorta), ponderosa pine (P. ponderosa), and Shasta red fir (Abies magnifica var. shastensis), are under study. After two growing seasons, gophers have caused only 5 percent mortality among Vexar -enclosed seedlings compared to 20 percent mortality among unprotected seedlings. In addition, stocking and heights of protected seedlings are better than those of unprotected seedlings. Problems associated with the use of Vexar included compression of the protectors by snow, breakage of the plastic during subfreezing temperatures, and protrusion of seedling terminals through mesh openings; however, these problems have been minor thus far. Information on long-term effectiveness and cost efficiency is still needed before we can recommend operational use of Vexar protectors for pocket gopher damage control
Salt budget in the Lake Washington ship canal system
Salt water enters the freshwater system of Lake Washington, Montlake Canal, Lake Union, Fremont Canal, and Salmon Bay through the U.S. Government Locks at Ballard…
The Ages of Elliptical Galaxies in a Merger Model
The tightness of the observed colour-magnitude and Mg- velocity
dispersion relations for elliptical galaxies has often been cited as an
argument against a picture in which ellipticals form by the merging of spiral
disks. A common view is that merging would mix together stars of disparate ages
and produce a large scatter in these relations. Here I use semi-analytic models
of galaxy formation to derive the distribution of the mean ages, colours and
metallicities of the stars in elliptical galaxies formed by mergers in a flat
CDM universe. It is seen that most of the stars in ellipticals form at
relatively high redshift (z > 1.9) and that the predicted scatter in the
colour-magnitude and Mg_2 - sigma relations falls within observational bounds.
I conclude that the apparent homogeneity in the properties of the stellar
populations of ellipticals is not inconsistent with a merger scenario for the
origin of these systems.Comment: latex file, figures available upon reques
Outskirts of Nearby Disk Galaxies: Star Formation and Stellar Populations
The properties and star formation processes in the far-outer disks of nearby
spiral and dwarf irregular galaxies are reviewed. The origin and structure of
the generally exponential profiles in stellar disks is considered to result
from cosmological infall combined with a non-linear star formation law and a
history of stellar migration and scattering from spirals, bars, and random
collisions with interstellar clouds. In both spirals and dwarfs, the far-outer
disks tend to be older, redder and thicker than the inner disks, with the
overall radial profiles suggesting inside-out star formation plus stellar
scattering in spirals, and outside-in star formation with a possible
contribution from scattering in dwarfs. Dwarf irregulars and the far-outer
parts of spirals both tend to be gas dominated, and the gas radial profile is
often non-exponential although still decreasing with radius. The ratio of
H-alpha to far-UV flux tends to decrease with lower surface brightness in these
regions, suggesting either a change in the initial stellar mass function or the
sampling of that function, or a possible loss of H-alpha photons.Comment: 20 pages, 8 figures, Invited review, Book chapter in "Outskirts of
Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and
Space Science Library, Springer, in pres
The K luminosity-metallicity relation for dwarf galaxies and the tidal dwarf galaxies in the tails of HCG 31
We determine a K-band luminosity-metallicity (K-Z) relation for dwarf
irregular galaxies, over a large range of magnitudes, -20.5 < M_K < -13.5,
using a combination of K photometry from either the 2-micron all sky survey
(2MASS) or the recent study of Vadivescu er al. (2005), and metallicities
derived mainly with the T_e method, from several different studies. We then use
this newly-derived relation, together with published K_s photometry and our new
spectra of objects in the field of HCG 31 to discuss the nature of the possible
tidal dwarf galaxies of this group. We catalogue a new member of HCG 31, namely
"R", situated ~40 kpc north of the group center, composed by a ring of H alpha
knots which coincides with a peak in HI. This object is a deviant point in the
K-Z relation (it has too high metallicity for its luminosity) and its projected
distance to the parent galaxy and large gas reservoir makes it one of the most
promising tidal dwarf galaxy candidates of HCG 31, together with object F. The
subsystems A1, E, F, H and R all have metallicities similar to that of the
galaxies A+C and B, result that is expected in a scenario where those were
formed from material expelled from the central galaxies of HCG 31. While
objects A1, E and H will most probably fall back onto their progenitors, F and
R may survive as tidal dwarf galaxies. We find that two galaxies of HCG 31, G
and Q, have A+em spectral signatures, and are probably evolving toward a
post-starburst phase.Comment: 32 pages, 4 figures - Submitted to AJ - A version of this paper with
full resolution figures can be found at
http://www.astro.iag.usp.br/~eduardo/HCG31-KZrelation.pd
Dark mammoth trunks in the merging galaxy NGC 1316 and a mechanism of cosmic double helices
NGC 1316 is a giant, elliptical galaxy containing a complex network of dark,
dust features. The morphology of these features has been examined in some
detail using a Hubble Space Telescope, Advanced Camera for Surveys image. It is
found that most of the features are constituted of long filaments. There also
exist a great number of dark structures protruding inwards from the filaments.
Many of these structures are strikingly similar to elephant trunks in H II
regions in the Milky Way Galaxy, although much larger. The structures, termed
mammoth trunks, generally are filamentary and often have shapes resembling the
letters V or Y. In some of the mammoth trunks the stem of the Y can be resolved
into two or more filaments, many of which showing signs of being intertwined. A
model of the mammoth trunks, related to a recent theory of elephant trunks, is
proposed. Based on magnetized filaments, the model is capable of giving an
account of the various shapes of the mammoth trunks observed, including the
twined structures.Comment: Accepted for publication in Astrophysics & Space Scienc
Trademarks and the Economic Dimensions of Trademark Law in Europe and Beyond
The economic analysis of trademark law continues to draw a number of commentaries, yet more and more, the courts are not factoring concrete economic analysis of trademark law and trademark protection in their decisions. In this entry I give an overview and status of trademarks from a law and economic perspective and suggest that trademark laws need to respond to the economic dimension that occurs on the market and consumer economic behavior.Peer reviewe
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