Intraday credit: risk, value, and pricing

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Competitive Interactions Between Two Closely Related Rhizomatous and Caespitose Perennial Grasses under Varying Conditions

Biomass, tiller numbers, flowering, and genet survival were accessed for the rhizomatous Elymus lanceolatus ssp. lanceolatus and caespitose E. l. ssp. wawawaiensis growing in mixtures with a range of densities of each taxon. Models of aboveground biomass of each taxon as a function of mixed densities were used to calculate competition indices. Tiller numbers and biomass of ssp. lanceolatus were higher than those of the caespitose taxon in the first year, but declined in the second year, while biomass and tiller numbers of ssp. wawawaiensis changed little. All tillers of ssp. wawawaiensis emerged in autumn; tillers of ssp. lanceolatus emerged from autumn through late spring. The rhizomatous taxon better exploited open resources in the first year; ssp. wawawaiensishad slower growth, but its production of many tillers early in the season may allow it to quickly exploit seasonally variable conditions of semiarid environments. Decline in flowering at higher densities and in the second year was more pronounced than that of biomass and tiller numbers. Genet survival was high and similar for both taxa. Substitution rates indicated ssp. lanceolatus was the better competitor in both years. In the second year, the two taxa differed somewhat less in substitution rates. A greater overlap in resources used by the two taxa was indicated. Subspecies lanceolatus experienced greater intensity of competition. Substitution rates and relative efficiency index indicated ssp. lanceolatus was the greater competitor between early and late spring, when overlap in resource use was greater. Another experiment addressed advantages of clonal foraging of ssp. lanceolatus in exploiting soil nutrient patches. A foraging response was found in the rhizomatous taxon, with greater numbers of closely spaced tillers in high-nutrient patches adjacent to the main clone, but root biomass in these patches, and aboveground biomass of the clones, indicated that both taxa accessed nutrients in the patches, but ssp. wawawaiens is used only root growth. The taxa were similar in their tolerance of low levels of soil nutrients. No difference among genets in degree of foraging response, and no relationship between degree of foraging response and fitness when nutrients are patchy were found. Subspecies lanceolatus did not show such a foraging response to high neighbor densities in mixed-density plots. Instead, rhizome lengths were reduced by higher neighbor densities and in the second year, by reduced resources overall

New Clock Comparison Searches for Lorentz and CPT Violation

We present two new measurements constraining Lorentz and CPT violation using the Xe-129 / He-3 Zeeman maser and atomic hydrogen masers. Experimental investigations of Lorentz and CPT symmetry provide important tests of the framework of the standard model of particle physics and theories of gravity. The two-species Xe-129 / He-3 Zeeman maser bounds violations of CPT and Lorentz symmetry of the neutron at the 10^-31 GeV level. Measurements with atomic hydrogen masers provide a clean limit of CPT and Lorentz symmetry violation of the proton at the 10^-27 GeV level.Comment: 11 pages, 5 figures. To appear in the Proceedings of the 3rd International Symposium on Symmetries in Subatomic Physic

DEVELOPMENT OF SEED TREATMENTS TO CONTROL BLACKBIRDS

Bird repellents to protect seeds are a potentially important aspect of integrated vertebrate pest management strategies. Yet, there currently are no repellents registered for seed treatment uses. This is due not to lack of effective candidate compounds, but to monetary and regulatory constraints that inhibit commercialization of promising compounds. Two examples of this dilemma are methiocarb and anthraquinone, each of which has considerable potential for bird repellent uses and each of which faces considerable registration hurdles as prospective seed treatment compounds. A concerted, coordinated effort among private industry, producer groups, and state and federal agencies may be the best strategy to bring potentially useful repellents to commercial reality

Repellency of Methyl Anthranilate to Captive Great Egrets

Because effective deterrents are hard to find, it has been suggested that methyl anthranilate (MA) be applied to the surface of fish ponds to discourage bird predation. We conducted two short-term evaluations of a formulation for this use, ReJeX-iT TP-40. First, we assessed the response of tropical fish to TP-40 applications in small wading pools. After 15 minutes, all fish virtually were motionless at or near the bottom of the pool. Fish in the control pools actively swam and most were within 3 cm of the surface of the pool. No mortality occurred, and fish activity returned to almost normal after 24 hrs. We also conducted feeding trials with captive-reared great egrets (Casmerodius albus), one of several bird species that regularly preys upon fish at aquaculture facilities. Birds were allowed to capture fish from untreated pools, and then the trials were repeated with 2 rates of TP-40 application. There were no differences in the number of fish eaten or in latency to first strike between the pretreatment day and either of the treatment days. The handling time increased markedly, however, as treatment rate increased. Although the TP-40 treatments appeared to bother the birds, the irritation was insufficient to prevent the egrets from feeding on fish in the ponds. In more natural feeding conditions, where fish availability and capture is not as predictable, such an increase in handling time might sufficiently alter the cost-benefit equation to discourage further use of a treated pool

Electron induced nanoscale engineering of rutile TiO2 surfaces

Electron stimulated modifications of the rutile TiO2(110) surface have been investigated using scanning tunnelling microscopy tip pulses and electron beam irradiation. Tip pulses on the 'as-prepared' surface induce local surface reconstruction and removal of surface hydroxyls in a region around the reconstruction. A defocused beam from an electron gun as well as tip pulses have been used to generate a number of oxygen deficient surfaces. All tip pulse features display an oval profile, which can be attributed to the anisotropic conductivity of the TiO2(110) surface. A novel oxygen deficient phase with well-ordered defective 'nano-cracks' has been identified, which can be produced by either electron beam irradiation or low flash anneal temperatures (~570 K). Annealing such surfaces to moderate temperatures (~850 K) leads to mixed 1 × 1 and 1 × 2 surfaces, until now only achievable by annealing in oxygen or ageing by repeated sputter/anneal cycles. Heating to normal preparation temperatures (1000 K) reforms the clean, well-ordered 1 × 1 surface termination. Our results demonstrate the potential of electron induced processes to modify the oxygen composition and structure of the TiO2(110) surface in a controllable and reversible way for selective surface patterning and surface reactivity modification

Non-equilibrium microtubule fluctuations in a model cytoskeleton

Biological activity gives rise to non-equilibrium fluctuations in the cytoplasm of cells; however, there are few methods to directly measure these fluctuations. Using a reconstituted actin cytoskeleton, we show that the bending dynamics of embedded microtubules can be used to probe local stress fluctuations. We add myosin motors that drive the network out of equilibrium, resulting in an increased amplitude and modified time-dependence of microtubule bending fluctuations. We show that this behavior results from step-like forces on the order of 10 pN driven by collective motor dynamics

Hydrocarbon Biogeochemical Setting of the Baffin Island Oil Spill Experimental Sites. I. Sediments

A baseline for petroleum residues in the sediments of the Cape Hatt Island in arctic Canada was obtained in anticipation of controlled oil releases of the Baffin Island Oil Spill (BIOS) Project. In subtidal sediments, the existing background of petroleum residues has an upper limit in the low to sub micro g/g concentration range. Petroleum was one of a variety of sources identified, including plant paraffin waxes and combustion products. Beach sediment hydrocarbons were quantitatively and qualitatively similar to those of subtidal sediments. The hydrocarbon baseline in sediments of the BIOS study area was found to be as low as might be found anywhere on earth and therefore ideally suited to the BIOS study.Key words: BIOS, arctic marine Canada, hydrocarbon baseline, sedimentsMots clés: BIOS, Arctique marin canadien, niveau de référence d'hydrocarbures, sédiment