214 research outputs found

    The Planning Process and People

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    Planning takes place on many levels, ranging from the individual to the nation and beyond. It can be related to a tremendous variety of situations and time spans, so there is no reason to expect the planning process to be uniform in its application. The particular elements of planning, the structures and techniques used, and the degrees of complexity will vary widely, depending on the conditions, issues and units of concern. About the only elements common to any planning are the assumptions that what happens today has consequences in the future, and that people can do things in the present that will increase the probabilities of particular events and situations matching their expectations or aspirations in the future. In other words, the planning process is predicated on the notions that the present is the father of the future, and people can purposely intervene to give some direction to the flow of events.Reviewed October 1993

    An Analysis of Cheliped Asymmetry in Three Species of Fiddler Crabs

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    Left-right cheliped asymmetry occurs in a variety of decapod species, Such asymmetries can be present in early development or can arise during sexual differentiation. Male fiddler crabs have a dimorphic enlargement of one of the two chelipeds. This major cheliped has been associated with male reproductive success as a result of female selection or advantage in male-male combat. Because the major cheliped occurs on either the right or the left side, selection pressure could produce populations with right or left cheliped dominance. To ascertain whether populations of dominantly enlarged right- or left-clawed males are present, three fiddler crab species, Uca longisignalis, U. minax and U. pugnax, from four North American marshes, two on the coast of the Atlantic Ocean, one on the coast of the Chesapeake Bay, and one on the coast of the Gulf of Mexico, were sampled. There were no significant differences in the number of males with right- or left-enlarged chelipeds within all species or marshes sampled. Similarly, when male crabs were grouped arbitrarily into two size classes (major chelipeds \u3c20 mm and 2:20 mm), the number of crabs with right or left major cheliped was similar among the size groups. Mean major propodus size for males was also similar for individuals with either right or left major chelipeds within each of the three species and four marshes. Comparison of morphometric parameters in each population indicated a strong correlation between claw size, carapace width, and carapace length, which was not affected by cheliped laterality. It appears that among these three species of Uca, there is no selection for males with cheliped enlargement on either the right or the left side within the geographical range of the species sampled

    BIBFRAME Transformation for Enhanced Discovery

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    With support from an internal innovation grant of the University of Illinois Library at Urbana-Champaign, researchers transformed and enriched nearly 300,000 e-book records in their library catalog from Machine-Readable Cataloging (MARC) records to Bibliographic Framework (BIBFRAME) linked data resources. Researchers indexed the BIBFRAME resources online, and created two search interfaces for the discovery of BIBFRAME linked data. One result of the grant was the incorporation of BIBFRAME resources within an experimental Bento view of the linked library data for e-books. The end goal of this project is to provide enhanced discovery of library data, bringing like sets of content together in contemporary and easy to understand views assisting users in locating sets of associated bibliographic metadata.University of Illinois Library Innovation FundOpe

    Reduced stiffness buckling analysis of aboveground storage tanks with thickness changes

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    The Reduced Stiffness Analysis (RSA) to compute lower bounds to buckling loads of shells has been employed by a number of researchers as a simple way to evaluate the buckling capacity of shells that display unstable behavior and imperfection-sensitivity. It allows the use of simple eigenvalue analysis, without having to perform incremental nonlinear analysis, and is based on the physical behavior of the shell which recognizes that a significant contribution to the stability of a shell under lateral pressure is provided by its membrane stiffness. Unstable post-critical behavior is associated with the loss of this stabilizing membrane contribution. Past use of the approach has been mainly restricted to cases of uniform shell thickness and uniform pressures in the circumferential direction, in which case analytical solutions are possible. Recent applications by the authors and other researchers have shown ways to compute the lower bounds using finite element analysis, for which a modified eigenvalue analysis is constructed by neglecting the membrane contributions to the matrix containing the initial stresses. This paper illustrates the application of the methodology to cases of pressure loaded shells with thickness changes in the meridional direction. A semi-analytical finite element code has been employed for the buckling analysis when uniform pressures act on aboveground steel tanks. The tanks are representative of those constructed for the oil industry, with diameter to thickness ratios of the order of 3000, and height to diameter ratios lower than one.Fil: Jaca, Rossana Claudia. Universidad Nacional del Comahue; ArgentinaFil: Godoy, Luis Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; ArgentinaFil: Croll, James G. A.. University College London; Reino Unid

    An Introduced Predator Alters Aleutian Island Plant Communities by Thwarting Nutrient Subsidies

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    The ramifying effects of top predators on food webs traditionally have been studied within the framework of trophic cascades. Trophic cascades are compelling because they embody powerful indirect effects of predators on primary production. Although less studied, indirect effects of predators may occur via routes that are not exclusively trophic. We quantified how the introduction of foxes onto the Aleutian Islands transformed plant communities by reducing abundant seabird populations, thereby disrupting nutrient subsidies vectored by seabirds from sea to land. We compared soil and plant fertility, plant biomass and community composition, and stable isotopes of nitrogen in soil, plants, and other organisms on nine fox-infested and nine historically fox-free islands across the Aleutians. Additionally, we experimentally augmented nutrients on a fox-infested island to test whether differences in plant productivity and composition between fox-infested and fox-free islands could have arisen from differences in nutrient inputs between island types. Islands with historical fox infestations had soils low in phosphorus and nitrogen and plants low in tissue nitrogen. Soils, plants, slugs, flies, spiders, and bird droppings on these islands had low δ15N values indicating that these organisms obtained nitrogen from internally derived sources. In contrast, soils, plants, and higher trophic level organisms on fox-free islands had elevated δ15N signatures indicating that they utilized nutrients derived from the marine environment. Furthermore, soil phosphorus (but not nitrogen) and plant tissue nitrogen were higher on fox-free than fox-infested islands. Nutrient subsidized fox-free islands supported lush, high biomass plant communities dominated by graminoids. Fox-infested islands were less graminoid dominated and had higher cover and biomass of low-lying forbs and dwarf shrubs. While δ15N profiles of soils and plants and graminoid biomass varied with island size and distance from shore, after accounting for these effects differences between fox-infested and fox-free islands still existed. Fertilization over four years caused a 24-fold increase in graminoid biomass and a shift toward a more graminoid dominated plant community typical of fox-free islands. These results indicate that apex predators can influence plant productivity and composition through complex interaction web pathways involving both top-down forcing and bottom-up nutrient exchanges across systems. Read More: http://www.esajournals.org/doi/abs/10.1890/05-049

    Pan-parastagonospora comparative genome analysis-effector prediction and genome evolution

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    We report a fungal pan-genome study involving Parastagonospora spp., including 21 isolates of the wheat (Triticum aestivum) pathogen Parastagonospora nodorum, 10 of the grass-infecting Parastagonospora avenae, and 2 of a closely related undefined sister species. We observed substantial variation in the distribution of polymorphisms across the pan-genome, including repeat-induced point mutations, diversifying selection and gene gains and losses.We also discovered chromosome-scale inter and intraspecific presence/absence variation of some sequences, suggesting the occurrence of one or more accessory chromosomes or regions that may play a role in host-pathogen interactions. The presence of known pathogenicity effector loci SnToxA, SnTox1, and SnTox3 varied substantially among isolates. Three P. nodorum isolates lacked functional versions for all three loci, whereas three P. avenae isolates carried one or both of the SnTox1 and SnTox3 genes, indicating previously unrecognized potential for discovering additional effectors in the P. nodorum-wheat pathosystem. We utilized the pangenomic comparative analysis to improve the prediction of pathogenicity effector candidates, recovering the three confirmed effectors among our top-ranked candidates. We propose applying this pan-genomic approach to identify the effector repertoire involved in other host-microbe interactions involving necrotrophic pathogens in the Pezizomycotina

    A photochemical model for the carbon-rich planet WASP-12b

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    The hot Jupiter WASP-12b is a heavily irradiated exoplanet in a short period orbit around a G0-star with twice the metallicity of the Sun. A recent thermochemical equilibrium analysis based on Spitzer and ground-based infrared observations suggests that the presence of ch4\ch4 in its atmosphere and the lack of \h2o features can only be explained if the carbon-to-oxygen ratio in the planet's atmosphere is much greater than the solar ratio (\ctoo = 0.54). Here, we use a 1-D photochemical model to study the effect of disequilibrium chemistry on the observed abundances of \h2o, \com, \co2 and ch4\ch4 in the WASP-12b atmosphere. We consider two cases: one with solar \ctoo and another with \ctoo = 1.08. The solar case predicts that \h2o and \com are more abundant than \co2 and ch4\ch4, as expected, whereas the high \ctoo model shows that \com, C2_{2}H2_{2} and HCN are more abundant. This indicates that the extra carbon from the high \ctoo model is in hydrocarbon species. \h2o photolysis is the dominant disequilibrium mechanism that alters the chemistry at higher altitudes in the solar \ctoo case, whereas photodissociation of C2_{2}H2_{2} and HCN is significant in the super-solar case. Furthermore, our analysis indicates that 2¸h2\c2h2 is the major absorber in the atmosphere of WASP-12b and the absorption features detected near 1.6 and 8 micron may be arising from C2_{2}H2_{2} rather than ch4\ch4. The Hubble Space Telescope's WFC3 can resolve this discrepancy, as 2¸h2\c2h2 has absorption between 1.511.541.51 - 1.54 microns, while ch4\ch4 does not.Comment: Accepted to Astrophysical Journal. Reaction list available with the journal version of the pape
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