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Reputational Externality and Self-Regulation
Professional associations and other producer groups often complain that their reputation is damaged by other groups providing a similar but lower-quality service and that the latter should be regulated. We examine the conditions under which a common regulatory regime can induce Pareto-improvements by creating a common reputation for quality among heterogeneous producers, when the regulator cannot commit to a given quality. A common reputation can be created only if the groups are not too different and if marginal cost is declining. High cost groups and small groups benefit most from forming a common regime
Distribution of Naegleria fowleri in Selected Northeast Arkansas Lakes
Seven northeast Arkansas recreational lakes were examined for the presence of pathogenic and nonpathogenic Naegleria fowleri. Cultural differentiation and microscopic morphology were used as species determining tests, while mouse pathogenicity tests were conducted to determine virulence. Only one isolate met all criteria utilized for definite identification of Naegleria fowleri, although Naegleria type organisms were found in all of the lakes. None of the isolates were pathogenic in mice
Quantification of the Effects of Data Denial and Limitation in MM5 Initialization on Forecast Accuracy
The current hub-and-spoke network in the European Theater is made up of locations built and organized around a Cold War threat. The threat of large-scale attrition warfare seems to have passed, and the threat of multiple, smaller scale contingencies has placed greater demands on the US military\u27s ability to transport equipment and personnel to multiple locations simultaneously. This research effort utilizes a Multiple Objective Linear Programming (MOLP) model to analyze optimal hub locations in USEUCOM. The model used to analyze the network was developed in Microsoft Excel and followed MOLP techniques to determine the trade-offs between the two constructs of importance time and cost. The results of the multiple model runs show that the Aviano hub alternative provides the least expensive and least time consuming option of the four alternatives considered. This came as no surprise. The use of a hub location that coincides with one of the demand locations eliminates the need for forward movement from the hub to the demand location. The reduction of cost and time in the optimal network should result in an overall savings to the entire network cost
Collective Reputation, Professional Regulation and Franchising
Collective reputation and its associated free-rider problem have been invoked to justify state licensing of professions and to explain the incidence of franchising. We examine the conditions under which it is possible to create a Pareto-improving collective reputation among groups of heterogeneous producers. If the regulator or franchisor cannot credibly commit to high quality then a common reputation can be created only if the groups are not too different and if marginal cost is declining. High cost groups benefit most from forming a common regime
Negative spatial regulation of the lineage specific CyIIIa actin gene in the sea urchin embryo
The CyIIIa·CAT fusion gene was injected into Strongylocentrotus purpuratus eggs, together with excess ligated competitor sequences representing subregions of the CyIIIa regulatory domain. In this construct, the chloramphenicol acetyltransferase (CAT) reporter gene is placed under the control of the 2300 nucleotide upstream regulatory domain of the lineage-specific CyIIIa cytoskeletal actin gene. CAT mRNA was detected by in situ hybridization in serial sections of pluteus stage embryos derived from the injected eggs. When carrier DNA lacking competitor CyIIIa fragments was coinjected with CyIIIa.CAT, CAT mRNA was observed exclusively in aboral ectoderm cells, i.e. the territory in which the CyIIIa gene itself is normally expressed (as also reported by us previously). The same result was obtained when five of seven different competitor subfragments bearing sites of DNA-protein interaction were coinjected. However, coinjection of excess quantities of either of two widely separated, nonhomologous fragments of the CyIIIa regulatory domain produced a dramatic ectopic expression of CAT mRNA in the recipient embryos. CAT mRNA was observed in gut, mesenchyme cells and oral ectoderm in these embryos. We conclude that these fragments contain regulatory sites that negatively control spatial expression of the CyIIIa gene
Depletion potentials in highly size-asymmetric binary hard-sphere mixtures: Comparison of accurate simulation results with theory
We report a detailed study, using state-of-the-art simulation and theoretical
methods, of the depletion potential between a pair of big hard spheres immersed
in a reservoir of much smaller hard spheres, the size disparity being measured
by the ratio of diameters q=\sigma_s/\sigma_b. Small particles are treated
grand canonically, their influence being parameterized in terms of their
packing fraction in the reservoir, \eta_s^r. Two specialized Monte Carlo
simulation schemes --the geometrical cluster algorithm, and staged particle
insertion-- are deployed to obtain accurate depletion potentials for a number
of combinations of q\leq 0.1 and \eta_s^r. After applying corrections for
simulation finite-size effects, the depletion potentials are compared with the
prediction of new density functional theory (DFT) calculations based on the
insertion trick using the Rosenfeld functional and several subsequent
modifications. While agreement between the DFT and simulation is generally
good, significant discrepancies are evident at the largest reservoir packing
fraction accessible to our simulation methods, namely \eta_s^r=0.35. These
discrepancies are, however, small compared to those between simulation and the
much poorer predictions of the Derjaguin approximation at this \eta_s^r. The
recently proposed morphometric approximation performs better than Derjaguin but
is somewhat poorer than DFT for the size ratios and small sphere packing
fractions that we consider. The effective potentials from simulation, DFT and
the morphometric approximation were used to compute the second virial
coefficient B_2 as a function of \eta_s^r. Comparison of the results enables an
assessment of the extent to which DFT can be expected to correctly predict the
propensity towards fluid fluid phase separation in additive binary hard sphere
mixtures with q\leq 0.1.Comment: 16 pages, 9 figures, revised treatment of morphometric approximation
and reordered some materia
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