Phylogeny and Adaptation in the Encelia Alliance (Asteraceae: Helliantheae)

The three related genera Encelia, Enceliopsis, and Geraea comprise the alliance. The first consists primarily of shrubs and the latter two of herbaceous perennials and an annual. With the exception of two Encelia species of arid South America, all inhabit southwestern North America. Enceliopsis and Geraea are sister groups, and together form the sister group to Encelia, which includes two major clades. Especially in Encelia, there are diverse morphologies and a variety of ecological strategies marked by differences in habitat, vestiture, water balance, and photosynthetic parameters. The North American species of all three genera are obligate outcrossers, all with n = 18 chromosomes. Although intergeneric hybrids are largely sterile, interspecific hybrids in Encelia are fertile in the wild and in cultivation. Hybrids in the wild are largely restricted to F1s, except in areas of human disturbance. Two true-breeding species are of homoploid hybrid origin, and are evidently isolated from the parent species through external ecological barriers involving selection against backcross progeny. Studies of the chloroplast genome and the intercistronic transcribed spacer (ITS) of nrDNA show clear differentiation of the genera, but much less variation within Encelia, even between phenotypically disparate species, suggesting recent divergence. Because the species are interfertile, it will be possible to study the genetics of the traits that distinguish the species and contribute to their differences

The Development of Building Block Methodologies to Produce Nanostructured Heterogeneous Catalysts by Design

Building block methods were successfully developed to demonstrate the potential of this approach to synthesizing nanostructured heterogeneous catalysts by design. The octa(trimethyltin) cuboctameric spherosilicate, Si8O20(SnMe3)8, was used as the building block for the synthesis of these materials. The solid state structure of this building block was characterized and compared to other solid state structures of Si8O12 containing compounds. These studies showed that this building block is composed of rigid tetrahedral units connect through a flexible siloxy bridge. The trimethyltin functionality present on this molecular precursor will react with metal chlorides to produce cross-linked metal oxide/silicate matrices where a distribution of different linking species is present. Three different silylchlorides were used to cross-link spherosilicate building blocks. The resulting products consisted of a distribution of different types of silylchloride linking units present in the solid material. Silylchlorides were used to study this reaction because the resulting product can easily be probed using silicon-29 solid-state NMR. The effect of initial stoichiometry on the distribution of linking groups in the resulting matrix was investigated and it was found that as the initial concentration of silylchloride decreased relative to the initial concentration of building blocks, the distribution of linking groups in the final product favored a more cross-linked matrix. These findings led to the development of synthetic strategies to produce a cross-linked matrix where a limiting amount of a silylchloride linking groups is present in the matrix having one type of environment throughout the entire material. These methods were then applied to reactions involving aluminum trichloride and titanium tetrachloride to produce solid acid catalysts. These catalysts were tested for the transesterification of triacetin with methanol. The catalysts were active for this reaction and triacetin conversion rates of 3 – 76% were observed after 8 hours. The titanosilicate catalysts were the most active and had reactive properties similar to commercially available catalysts

Multiple Model Adaptive Estimation and Control Redistribution Performance on the VISTA F-16 During Partial Actuator Impairments

Multiple Model Adaptive Estimation with Control Reconfiguration (MMAE/CR) capability to estimate and compensate for partial actuator failures, or impairments is investigated using the high-fidelity, nonlinear, six-degree-of-freedom, VISTA F-16 simulation which currently resides on the Simulation Rapid-Prototyping Facility (SRF). After developing a model for inserting partial actuator impairments into the VISTA F-16 truth model, research begins with a battery of single actuator impairment tests. This stage of research explores the capability of the existing MMAE algorithm to estimate single, partial actuator impairments, and helps to define refinements and expansions needed in the MMAE algorithm for the second phase of research: the detection and estimation of dual, total and partial actuator impairments. It is seen from the first stage of research that, while MMAE is able to estimate partial impairments, there are refinements needed, such as probability smoothing and quantization , to compensate for the quality of MMAE probability data and to provide a better, more stable estimate value to the Control Reconfiguration module. The Kalman filters and the dual, partial failure filter banks necessary for the detection of dual, partial actuator impairments are also defined as a result of the single impairment tests. Fifteen more banks of partial first-failure Kalman filters are added to the existing MMAE algorithm, as well as the bank swapping logic necessary to transition to them. Once the revised and expanded MMAE/CR algorithm is ready, research begins on dual combinations of total and partial actuator impairments. While results of these tests (for other than total impairments) are not as good as originally hoped or expected, the potential_for better performance is evident

U.S. Import Demand for Tilapia from Selected FTAA Countries

Seafood consumption in the U.S. has increased over the period 1990 to 2003. A large percentage of the seafood consumed in the U.S. is imported. The most important seafood products imported to the U.S. are shrimp, Atlantic salmon, tilapia, catfish, crayfish, mussels and a mixture of mollusks. In 2003, the U.S. imported 199 million pounds of tilapia and tilapia products, at a value of $241.2 million, a 38$77,952 (Aquaculture Outlook, 2004). Given that tilapia culture may be a promising enterprise for CARICOM and FTAA member countries, it is important to evaluate changes in U.S. market demand for tilapia from CARICOM countries. A Source Differentiated Almost Ideal Demand System (SDAIDS) model was used to conduct an import demand study for tilapia and tilapia products in the U.S. The own price elasticity of Jamaica frozen fillet was found to be -0.23, and significant which means that it is price inelastic and which means that increases in exports, other factors remaining constant, may lead to a fall in total revenue. The Jamaican frozen fillet is complementary to that of the rest of the world (ROW) and fresh fillet from Ecuador, but competitive (substitute) to fresh-frozen fillet from Thailand. Fresh fillet from Ecuador, with a cross price elasticity of 0.29, is a substitute for the fresh fillet from Costa Rica. The fresh fillet from Costa Rica is complementary to the fresh-frozen from Thailand. The fresh fillet from Honduras with a cross price elasticity of 1.13 is a substitute for the fresh fillet from Ecuador. However, the fresh fillet from Honduras is a complement to the frozen fillet from Thailand. Seafood consumption in the U.S. has increased over the period 1990 to 2003. A large percentage of the seafood consumed in the U.S. is imported. The most important seafood products imported to the U.S. are shrimp, Atlantic salmon, tilapia, catfish, crayfish, mussels and a mixture of mollusks. In 2003, the U.S. imported 199 million pounds of tilapia and tilapia products, at a value of $241.2 million, a 38$77,952 (Aquaculture Outlook, 2004). Given that tilapia culture may be a promising enterprise for CARICOM and FTAA member countries, it is important to evaluate changes in U.S. market demand for tilapia from CARICOM countries. A Source Differentiated Almost Ideal Demand System (SDAIDS) model was used to conduct an import demand study for tilapia and tilapia products in the U.S. The own price elasticity of Jamaica frozen fillet was found to be -0.23, and significant which means that it is price inelastic and which means that increases in exports, other factors remaining constant, may lead to a fall in total revenue. The Jamaican frozen fillet is complementary to that of the rest of the world (ROW) and fresh fillet from Ecuador, but competitive (substitute) to fresh-frozen fillet from Thailand. Fresh fillet from Ecuador, with a cross price elasticity of 0.29, is a substitute for the fresh fillet from Costa Rica. The fresh fillet from Costa Rica is complementary to the fresh-frozen from Thailand. The fresh fillet from Honduras with a cross price elasticity of 1.13 is a substitute for the fresh fillet from Ecuador. However, the fresh fillet from Honduras is a complement to the frozen fillet from Thailand. The FTAA member states, other than Ecuador, are not major players in the frozen whole tilapia market. Large non-member countries, such as Thailand, Taiwan, and China, may be serious threats to CARICOM and FTAA member country tilapia products in the U.S. market. The FTAA member countries have concentrated on the fresh-frozen fillet and may have a comparative advantage for this product line because of proximity to the market.Tilapia, sea-food, Almost-Ideal-Demand-System, import, FTAA countries, Agribusiness, Agricultural and Food Policy, Food Security and Poverty, International Relations/Trade, Research Methods/ Statistical Methods,

Elucidating EU Engagement: Rethinking Dimensions of Supranational Participation

Some observers of the EU have expressed concern about the quality of its democratic governance. Such sentiments are reflected in much of the research conducted on attitudes toward the EU and voting in European Parliament elections, both of which seek to assess the vibrancy of public engagement with the European project. Yet few—if any—have considered other types of behavior that may be associated with an active EU citizenry. This paper uses original survey data from the United Kingdom to complement existing research by identifying a fuller picture of the types and frequency of EU participation. We also assess the extent to which predictors from existing public opinion literature (identity threat, economic concerns, political attitudes and sociodemographics) predict these various types of participation. Results suggest that citizens pursue a wide array of participation avenues and that different sets of motivations underpin these different types of EU engagement

Lullaby Song

https://digitalcommons.library.umaine.edu/mmb-vp/5708/thumbnail.jp

Secondary Flow Control in Low Aspect Ratio Vanes Using Splitters

Low aspect ratio vanes, often the result of overall engine architecture constraints, create strong secondary flows and high end-wall loss. In this paper, a splitter concept is demonstrated that reduces secondary flow strength and improves stage performance. An analytic conceptual study, corroborated by inviscid computations, shows that the total secondary kinetic energy (SKE) of the secondary flow vortices is reduced when the number of passages is increased and, for a given number of vanes, when the inlet end-wall boundary layer is evenly distributed between the passages. Viscous computations show that, for this to be achieved in a splitter configuration, the pressure-side leg of the low aspect ratio vane horseshoe vortex, must enter the adjacent passage (and not “jump” in front of the splitter leading edge). For a target turbine application, four vane designs were produced using a multi-objective optimization approach. These designs represent current practice for a low aspect ratio vane, a design exempt from thickness constraints, and two designs incorporating splitter vanes. Each geometry is tested experimentally, as a sector, within a low-speed turbine stage. The vane designs with splitter geometries were found to reduce the measured secondary kinetic energy, by up to 85%, to a value similar to the design exempt from thickness constraints. The resulting flow field was also more uniform in both the circumferential and radial directions. One splitter design was selected for a full annulus test where a mixed-out loss reduction, compared to the current practice design, of 15.3% was measured and the stage efficiency increased by 0.88%.The work was funded by Rolls-Royce plc under the SILOET 2 work package