7,889 research outputs found
Fixed Point Indices and Manifolds with Collars
This paper concerns a formula which relates the Lefschetz number L(f) for a
map f:M --> M' to the fixed point index I(f) summed with the fixed point index
of a derived map on part of the boundary of M. Here M is a compact manifold and
M' is M with a collar attached.Comment: Accepted for publication in Fixed Point Theory and Applications as
part of the proceedings of the Newfoundland conference on fixed points, 200
MARKETING MECHANISMS TO FACILITATE CO-EXISTENCE OF GM AND NON-GM CROPS
Development of genetically modified (GM) and specialty crops has had a great impact on the grain handling industry during recent years. Added costs associated with handling these crops have become an important issue for grain handlers. For this study, data were collected from a survey of elevators in the Upper Midwest. The information focused on segregation practices, time requirements, and costs. This study shows the different costs (grading and handling) associated with segregation practices at the grain-handler level. The results revealed that the cost of modifying systems to handle GM is of major importance. A stochastic simulation model of an engineering cost function is developed to analyze costs for segregation and testing using results from the survey. Assuming no modification is required, the total cost of segregation is about 10 cents per bushel. The volume of grain tested also impacts the total segregation cost per bushel. Finally, the gross elevator margin and the premium for quality seem to be large enough to offset the increase in handling costs due to these new segregation practices.Genetically modified crops, identity preservation, segregation, Crop Production/Industries,
Characterization of wave transport in non-conservative media with random and correlated disorder
Passive quasi-one-dimensional random media exhibit one of the three regimes of transport - ballistic, diffusive, or Anderson localization - depending on system size. The ballistic and diffusion approximations assumes particle transport, whereas Anderson Localization occurs when wave self-interference effects are dominant. When the system contains absorption or gain, then how the regimes can be characterized becomes unclear. By investigating theoretically and numerically the ratio of transmission to energy in a random medium in one dimension, we show this parameter can be used to characterize localization in random media with gain. Non-conservative media implies a second dimension for the transport parameter space, namely gain/absorption. By studying the relations between the transport mean free path, the localization length, and the gain or absorption lengths, we enumerate fifteen regimes of wave propagation through quasi-one-dimensional nonconservative random media. Next a criterion characterizing the transition from diffusion to Anderson localization is developed for random media with gain or absorption. The position-dependent diffusion coefficient, which is closely related to the ratio of transmission to energy stored in the system, is investigated using numerical models. In contrast to random structures, deterministic aperiodic structures (DAS) offer predictable and reproducible transport behaviors while exhibiting a variety of unusual transport properties not found in either ordered or random media. By manipulating structural correlations one may design and fabricate artificial photonic nanomaterials with prescribed transport properties. The Thue-Morse structure is a prime example of deterministic aperiodic systems with singular-continuous spatial Fourier spectra. The non-periodic nature of the system makes it notoriously difficult to characterize theoretically especially in dimensions higher than one. The possibility of mapping the two-dimensional aperiodic Thue-Morse pattern of micro-cavities onto a square lattice is demonstrated, making it amenable to the tight-binding description --Abstract, page iv
Continuous chlorosulfonation of benzene : I. Phase relations
This work presents liquid-liquid equilibria data on a system suitable for continuous chlorosulfonation of benzene. Complete information is presented for the ternary, chlorosulfonic acid - sulfuric acid - carbon tetrachloride. A partial investigation of the ternary systems, chlorosulfonic acid - sulfuric acid - benzenesulfonyl chloride; chlorosulfonic acid - carbon tetrachloride - benzenesulfonyl chloride; and the quaternary system, carbon tetrachloride - benzenesulfonyl chloride sulfuric acid - chlorosulfonic acid is also presented
The evolutionary emergence of neural organisation in computational models of primitive organisms
Over the decades, the question why did neural organisation emerge in the way that it did? has proved to be massively elusive. Whilst much of the literature paints a picture of common ancestry the idea that a species at the root of the tree of nervous system evolution spawned numerous descendants the actual evolutionary forces responsible for such changes, major transitions or otherwise, have been less clear. The view presented in this thesis is that via interactions with the environment, neural organisation has emerged in concert with the constraints enforced by body plan morphology and a need to process information eciently and robustly. Whilst these factors are two smaller parts of a much greater whole, their impact during the evolutionary process cannot be ignored, for they are fundamentally signicant. Thus computer simulations have been developed to provide insight into how neural organisation of an articial agent should emerge given the constraints of its body morphology, its symmetry, feedback from the environment, and a loss of energy. The first major finding is that much of the computational process of the nervous system can be ooaded to the body morphology, which has a commensurate bearing on neural architecture, neural dynamics and motor symmetry. The second major finding is that sensory feedback strengthens the dynamic coupling between the neural system and the body plan morphology, resulting in minimal neural circuitry yet more ecient agent behaviour. The third major finding is that under the constraint of energy loss, neural circuitry again emerges to be minimalistic. Throughout, an emphasis is placed on the coupling between the nervous system and body plan morphology which are known in the literature to be tightly integrated; accordingly, both are considered on equal footings
- …