12,591 research outputs found

    Effects of Enamel Paint on the Behavior and Survival of the Periodical Cicada, \u3ci\u3eMagicicada Septendecim\u3c/i\u3e (Homoptera) and the Lesser Migratory Grasshopper, \u3ci\u3eMelanoplus Sanguinipes (Orthoptera).

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    We present information compiled from several studies on the effects of methods for marking individual arthropods on their longevity and behavior. Results from our own research on effects of enamel paint marking on two in- sect species, the periodical cicada, Magicicada septendecim, and the lesser migratory grasshopper, Melanoplus sanguinipes, are also presented. Neither species showed any adverse survivorship or behavioral effects from marking

    Effect of delayed acquisition times on Gadolinium-enhanced MRI of the presumably normal canine brain

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    A delay in imaging following intravenous contrast medium administration has been recommended to reduce misdiagnoses. However, the normal variation of contrast enhancement in dogs following a delay has not been characterized. Contrast enhanced MR imaging of 22 dogs was assessed, in terms of identification of normal anatomic structures, to investigate the variation associated with 10 minute delay between contrast medium administration and imaging. All dogs had a normal brain MR imaging study and unremarkable CSF. Specific ROIs were assessed both objectively, using computer software, and subjectively using three observers. Mean contrast enhancement greater than 10% was seen in the pituitary gland, choroid plexus, meninges, temporal muscle, trigeminal nerve and the trigeminal nerve root. Structures with an active blood-brain-barrier had minimal contrast enhancement (<6%). Enhancing structures had significantly more contrast enhancement at t=1min versus t=10min, except in temporal muscle, the trigeminal nerve and the trigeminal nerve root. Inter-observer agreement was moderate to good in favor of the initial post contrast T1w sequence. The observers found either no difference or poor agreement in identification of the non-vascular structures. Intra-observer agreement was very good with all vascular structures and most non-vascular structures. A degree of meningeal enhancement was a consistent finding. The initial acquisition had higher enhancement characteristics and observer agreement for some structures; however, contrast-to-noise was comparable in the delayed phase or not significantly different. We provide baseline references and suggest that the initial T1w post contrast sequence is preferable but not essential should a delayed post contrast T1w sequence be performed

    Further relationships in the grunwald treatment of acid-base equilibria in hydroxylic solvents

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    The problem under consideration is an attempt to establish a quantitative relationship among the basicities of a series of compounds. such a problem is trivial in the case in which all of the compounds of interest can be observed in the same medium. However, it frequently occurs that considerations of solubility and leveling effect of a solvent make it difficult or impossible to carry out suitable experiments. In these cases the experimenter\u27s only recourse generally has been to find a more suitable solvent

    Fermion Helicity Flip Induced by Torsion Field

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    We show that in theories of gravitation with torsion the helicity of fermion particles is not conserved and we calculate the probability of spin flip, which is related to the anti-symmetric part of affine connection. Some cosmological consequences are discussed.Comment: 6 pages, to appear in Europhysics Letter

    Substituent effects of the stability of metal chelates

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    The stability constants of the chelate compounds of a series of substituted diaroylmethanes with several divalent metals in 75 per cent by volume dioxan-water were measured. The data were treated with the Hammett relationship

    Hip structure and locomotion in ambulatory and cursorial carnivores reinvestigated [abstract]

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    Understanding how the femoral head articulates with the acetabulum of the pelvis should allow one to infer the pattern of hip mobility in living and fossil species. In 1977, Jenkins and Camazine analyzed cineradiographic films of carnivores (cat, dog, raccoon) during locomotion. They hypothesized that raccoons, which climb trees as well as walk terrestrially, would have hip joints adapted for greater abduction, where as the nearly strictly terrestrial dogs would have more adducted hips, and cats would be intermediate. Inferences made in this study have been used extensively to infer locomotor behavior and evolution in primates, although they were not tested thoroughly due to methodological limitations at the time. We tested the hypothesis that ambulatory carnivores (raccoons; Procyonidae) would have shallower acetabulae, lower greater trochanters, higher femoral neck-shaft angle and higher position of the fovea capitis than terrestrial ones (dogs; Canidae), and that cats (Felidae) would be intermediate

    Research notes: Glyceride structure variation in soybean varieties

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    The glyceride structure of an oil, i.e., the combinations of fatty acids that occur together in the triglycerides, may influence its stability to oxidation (Raghuveer and Hammond, 1967). Recently we examined the glyceride structure of about 20 varieties of soybean and related species by two techniques: stereospecific analysis and silver ion chromatography (Fatemi and Hammond, 1977a, 1977b) . Stereospecific analysis measures the proportion of each fatty acid on each of the three positions of glycerol

    Effects of a torsion field on Big Bang nucleosynthesis

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    In this paper it is investigated whether torsion, which arises naturally in most theories of quantum gravity, has observable implications for the Big Bang nucleosynthesis. Torsion can lead to spin flips amongst neutrinos thus turning them into sterile neutrinos. In the early Universe they can alter the helium abundance which is tightly constrained by observations. Here I calculate to what extent torsion of the string theory type leads to a disagreement with the Big Bang nucleosynthesis predictions.Comment: accepted by General Relativity and Gravitatio

    A measurement of noise created by fluctuating electrostatic charges on dielectric surfaces using a torsion balance

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    Future gravitational wave detectors could have their sensitivity significantly limited, at frequencies below 10 Hz, by the presence of fluctuating electrostatic charges on the dielectric surfaces of the detector optics. A confirmed observation of the effect of fluctuating charges, or charging noise, in a gravitational wave detector has still to be made and it has never been experimentally verified by any other means. This paper presents a direct measurement of the fluctuating force noise created by moving charges on a dielectric surface using a servo controlled torsion balance. The results confirm that the fluctuating force noise caused by excess charges can be best described by a Markov process with a single correlation time and has a frequency dependence of f<sup>-1</sup&gt
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