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Small Cost (small + cost)
Selected AbstractsSEXUAL SELECTION AND THE EVOLUTION OF COSTLY FEMALE PREFERENCES: SPATIAL EFFECTSEVOLUTION, Issue 3 2000Troy Day Abstract., Models of Fisher's runaway process show that if there is a cost to female preference, no preference or male trait exaggeration will evolve. Surprisingly, this is true no matter how small the cost, which reveals that these models of Fisher's process are structurally unstable (Bulmer 1989). Here a model of Fisher's runaway process is presented to demonstrate that costly female preference evolves very easily when space is explicitly included in the model. The only requirement is that the optimal male phenotype changes across the species' range. The model shows that the spatial average of the female preference and male trait reach an evolutionary equilibrium that is identical to those of nonspatial models, but that the preference and male trait can deviate greatly from these averages at any point in space. For example, if random mating results in the lowest cost to females, then at equilibrium the spatial average preference will be zero. Nevertheless, there will be some locations at which females prefer males with larger ornaments and others where they prefer males with smaller ornaments. Results also show that the structural instability of nonspatial models of Fisher's process is less of a problem in spatial models. In particular, many of the main qualitative features of cost-free spatial models of Fisher's process remain valid even when there are small costs of female preference. Finally, the model shows that abrupt changes in the optimal male phenotype across space can result in an amplification of this pattern when preference has a small cost, but it can also result in a pattern similar to reproductive character displacement. Which of these occurs depends on the magnitude of the cost of female preference. This suggests that some patterns of reproductive character displacement in nature might be explained simply by sexual selection rather than by hybrid dysgenesis and reinforcement. [source] Elastohydrodynamics of tensioned web roll coating processINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 6 2003M. S. Carvalho Abstract Coating process is an important step in the manufacturing of different products, such as paper, adhesive and magnetic tapes, photographic films, and many other. The tensioned web roll coating is one the several methods used by different industries. It relies on the elastohydrodynamic action between the fluid and the tensioned substrate for transferring and applying the liquid. The main advantage of this method is its ability to apply very thin liquid layers with less sensitivity to mechanical tolerance at relative small cost. Despite its industrial application, theoretical analysis and fundamental understanding of the process are limited. This work analyses this elastohydrodynamic action by solving the differential equations that govern the liquid flow, described by the Navier,Stokes equation, and the web deformation, modelled by the cylindrical shell approximation. The goal is to determine the operating conditions at which the process is two dimensional and defect free. The equations are discretized by the Galerkin/finite-element method. The resulting non-linear system of equations is solved by Newton's method coupled with pseudo-arc-length continuation in order to obtain solutions around turning points. The theoretical results are used to construct an operating window of the process that is in agreement with limited experimental data. Copyright © 2003 John Wiley & Sons, Ltd. [source] Protein EqualizerÔ Technology, : The quest for a "democratic proteome"PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2006Pier Giorgio Righetti Professor Abstract No proteome can be considered "democratic", but rather "oligarchic", since a few proteins dominate the landscape and often obliterate the signal of the rare ones. This is the reason why most scientists lament that, in proteome analysis, the same set of abundant proteins is seen again and again. A host of pre-fractionation techniques have been described, but all of them, one way or another, are besieged by problems, in that they are based on a "depletion principle", i.e. getting rid of the unwanted species. Yet "democracy" calls not for killing the enemy, but for giving "equal rights" to all people. One way to achieve that would be the use of "Protein Equalizer Technology" for reducing protein concentration differences. This comprises a diverse library of combinatorial ligands coupled to spherical porous beads. When these beads come into contact with complex proteomes (e.g. human urine and serum, egg white, and any cell lysate, for that matter) of widely differing protein composition and relative abundances, they are able to "equalize" the protein population, by sharply reducing the concentration of the most abundant components, while simultaneously enhancing the concentration of the most dilute species. It is felt that this novel method could offer a strong step forward in bringing the "unseen proteome" (due to either low abundance and/or presence of interference) within the detection capabilities of current proteomics detection methods. Examples are given of equalization of human urine and serum samples, resulting in the discovery of a host of proteins never reported before. Additionally, these beads can be used to remove host cell proteins from purified recombinant proteins or protein purified from natural sources that are intended for human consumption. These proteins typically reach purities of the order of 98%: higher purities often become prohibitively expensive. Yet, if incubated with "equalizer beads", these last impurities can be effectively removed at a small cost and with minute losses of the main, valuable product. [source] Uniform random sampling of planar graphs in linear time,RANDOM STRUCTURES AND ALGORITHMS, Issue 4 2009Éric Fusy Abstract This article introduces new algorithms for the uniform random generation of labelled planar graphs. Its principles rely on Boltzmann samplers, as recently developed by Duchon, Flajolet, Louchard, and Schaeffer. It combines the Boltzmann framework, a suitable use of rejection, a new combinatorial bijection found by Fusy, Poulalhon, and Schaeffer, as well as a precise analytic description of the generating functions counting planar graphs, which was recently obtained by Giménez and Noy. This gives rise to an extremely efficient algorithm for the random generation of planar graphs. There is a preprocessing step of some fixed small cost; and the expected time complexity of generation is quadratic for exact-size uniform sampling and linear for uniform approximate-size sampling. This greatly improves on the best previously known time complexity for exact-size uniform sampling of planar graphs with n vertices, which was a little over O(n7). © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2009 [source] Intersectoral Labor Mobility and the Growth of the Service SectorECONOMETRICA, Issue 1 2006Donghoon Lee One of the most striking changes in the U.S. economy over the past 50 years has been the growth in the service sector. Between 1950 and 2000, service-sector employment grew from 57 to 75 percent of total employment. However, over this time, the real hourly wage in the service sector grew only slightly faster than in the goods sector. In this paper, we assess whether or not the essential constancy of the relative wage implies that individuals face small costs of switching sectors, and we quantify the relative importance of labor supply and demand factors in the growth of the service sector. We specify and estimate a two-sector labor market equilibrium model that allows us to address these empirical issues in a unified framework. Our estimates imply that there are large mobility costs: output in both sectors would have been double their current levels if these mobility costs had been zero. In addition, we find that demand-side factors, that is, technological change and movements in product and capital prices, were responsible for the growth of the service sector. [source] SEXUAL SELECTION AND THE EVOLUTION OF COSTLY FEMALE PREFERENCES: SPATIAL EFFECTSEVOLUTION, Issue 3 2000Troy Day Abstract., Models of Fisher's runaway process show that if there is a cost to female preference, no preference or male trait exaggeration will evolve. Surprisingly, this is true no matter how small the cost, which reveals that these models of Fisher's process are structurally unstable (Bulmer 1989). Here a model of Fisher's runaway process is presented to demonstrate that costly female preference evolves very easily when space is explicitly included in the model. The only requirement is that the optimal male phenotype changes across the species' range. The model shows that the spatial average of the female preference and male trait reach an evolutionary equilibrium that is identical to those of nonspatial models, but that the preference and male trait can deviate greatly from these averages at any point in space. For example, if random mating results in the lowest cost to females, then at equilibrium the spatial average preference will be zero. Nevertheless, there will be some locations at which females prefer males with larger ornaments and others where they prefer males with smaller ornaments. Results also show that the structural instability of nonspatial models of Fisher's process is less of a problem in spatial models. In particular, many of the main qualitative features of cost-free spatial models of Fisher's process remain valid even when there are small costs of female preference. Finally, the model shows that abrupt changes in the optimal male phenotype across space can result in an amplification of this pattern when preference has a small cost, but it can also result in a pattern similar to reproductive character displacement. Which of these occurs depends on the magnitude of the cost of female preference. This suggests that some patterns of reproductive character displacement in nature might be explained simply by sexual selection rather than by hybrid dysgenesis and reinforcement. [source] Technological Incompatibility, Endogenous Switching Costs and Lock-inTHE JOURNAL OF INDUSTRIAL ECONOMICS, Issue 3 2001Begoña Garcia Mariñoso Systems are goods comprising of durables that are sequentially updated with complements. With sequential purchases, if suppliers produce incompatible brands, consumers who upgrade systems with complements of a different brand must replace the durables they own. Thus, the price of these durables is an endogenous switching cost. The paper deals with the concern that firms may use incompatibility to create consumer's switching costs to reduce competition in aftermarkets. However, it shows that, with homogenous durables, and small costs of reaching compatibility, endogenous switching costs increase intertemporal price competition to the extent that producers prefer to have compatible technologies. [source] | ||||||||||