5,777 research outputs found

    Growth Rate, Life Span and Molting Cycle of the Crayfish Orconectes Sanborni

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    Author Institution: The Department of Zoology, The Ohio State UniversityOrconectes sanborni young were found to hatch in the spring and to undergo several closely spaced molts. These juveniles could be sexed by mid-summer. A molt occurring in the autumn of the first year was the beginning of a pattern of two molts per year, one in the spring and one in the summer or autumn, although the precise timing of these molts was variable. Both sexes usually reached sexual maturity by the autumn of the second year. At this time the males became form I (breeding) and the oocytes in the females began to increase in size. The maximum life span was found to be thirty-seven months

    Crayfish and Bivalve Distribution in a Valley in Southwestern Ohio

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    Author Institution: Department of Zoology, The Ohio State UniversityThe crayfish and bivalve fauna of 2 stream systems in an ancient valley in southwestern Ohio were examined. The distribution of the various species was mapped and the topography and environmental conditions of each collecting site were noted. The greatest diversity of species was usually found at the edge of the valley, while environmentally stressed sites harbored neither decapods nor bivalves. One species of crayfish, Orconectes sloanii, was found in the northwestern drainage system of the valley, but not in the southeastern drainage system, even though the 2 stream systems were once connected

    Finite-dimensional Gaussian approximation with linear inequality constraints

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    International audienceGaussian process (GP) modulated Cox processes are widely used to model point patterns. Existing approaches require a mapping (link function) between the unconstrained GP and the positive intensity function. This commonly yields solutions that do not have a closed form or that are restricted to specific covariance functions. We introduce a novel finite approximation of GP-modulated Cox processes where positiveness conditions can be imposed directly on the GP, with no restrictions on the covariance function. Our approach can also ensure other types of inequality constraints e.g. monotonicity, convexity), resulting in more versatile models that can be used for other classes of point processes (e.g. renewal processes). We demonstrate on both synthetic and real-world data that our framework accurately infers the intensity functions. Where monotonicity is a feature of the process, our ability to include this in the inference improves results

    Recent advances in the application of carbohydrates as renewable feedstocks for the synthesis of nitrogen-containing compounds

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    Carbohydrates, in the form of chitin, chitosan and cellulose, are one of the most available, renewable, and sustainable chemical feedstocks. Their conversion to biofuels, fine chemicals, and industrially-relevant monomers is becoming increasingly viable and promising as innovation decreases the price of this technology, and climate change and the price of fossil fuels increases the social and economic costs of using traditional feedstocks. In recent years, carbohydrates have been increasingly used as sources for nitrogen-containing fine chemicals. This chapter, with 86 references, provides a brief overview of the conversion of carbohydrate biomass to the standard hydrocarbon and oxygen-containing derivatives, and then provides a survey of recent progress in converting the biopolymers, and the derived mono and di-saccharides, into nitrogen-containing molecules with a special focus on N-heterocycle synthesis for medicinal applications

    Ionization-induced asymmetric self-phase modulation and universal modulational instability in gas-filled hollow-core photonic crystal fibers

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    We study theoretically the propagation of relatively long pulses with ionizing intensities in a hollow-core photonic crystal fiber filled with a Raman-inactive gas. Due to photoionization, previously unknown types of asymmetric self-phase modulation and `universal' modulational instabilities existing in both normal and anomalous dispersion regions appear. We also show that it is possible to spontaneously generate a plasma-induced continuum of blueshifting solitons, opening up new possibilities for pushing supercontinuum generation towards shorter and shorter wavelengths.Comment: 5 pages, 4 figure
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