977 research outputs found

    Substitution in a sense

    Get PDF
    The Reference Principle (RP) states that co-referring expressions are everywhere intersubstitutable salva congruitate. On first glance, (RP) looks like a truism, but a truism with some bite: (RP) transforms difficult philosophical questions about co-reference into easy grammatical questions about substitutability. This has led a number of philosophers to think that we can use (RP) to make short work of certain longstanding metaphysical debates. For example, it has been suggested that all we need to do to show that the predicate ‘( ) is a horse’ does not refer to a property is point out that ‘( ) is a horse’ and ‘the property of being a horse’ are not everywhere intersubstitutable salva congruitate. However, when we understand ‘substitution’ in the simplest and most straightforward way, (RP) is no truism; in fact, natural languages are full of counterexamples to the principle. In this paper, I introduce a new notion of substitution, and then develop and argue for a version of (RP) that is immune to these counterexamples. Along the way I touch on the following topics: the relation between argument forms and their natural language instances; the reification of sense; the difference between terms and predicates; and the relation between reference and disquotation. I end by arguing that my new version of (RP) cannot be used to settle metaphysical debates quite as easily as some philosophers would like

    Electromagnetic corrections to π−\pi ^-p scattering length from pionic hydrogen

    Get PDF
    We derive a closed, model space independent, expression for the electromagnetic correction factor Ύ\delta to the scattering length aa extracted from a hydrogenic atom with an extended charge to order α2\alpha ^2 and a3a^3 in the limit of a short ranged hadronic interaction.Comment: 4 pages; PANIC02, XVIth Conference on Particles and Nuclei, Osaka, to appear in Nuclear Physics

    Lickometry: A novel and sensitive method for assessing functional deficits in rats after stroke

    Get PDF
    The need for sensitive, easy to administer assessments of long-term functional deficits is crucial in pre-clinical stroke research. In the present study, we introduce lickometry (lick microstructure analysis) as a precise method to assess sensorimotor deficits up to 40 days after middle cerebral artery occlusion in rats. Impairments in drinking efficiency compared to controls, and a compensatory increase in the number of drinking clusters were observed. This highlights the utility of this easy to administer task in assessing subtle, long-term deficits, which could be likened to oral deficits in patients

    Spin asymmetries for elastic proton scattering and the spin dependent couplings of the Pomeron

    Full text link
    This paper serves as a report on the large amount of analysis done in conjunction with the polarized proton program at RHIC. This comprises elastic scattering data of protons on protons in colliding beam or fixed target mode and proton beams on carbon targets. In addition to providing a model for the energy dependence of the analyzing power of elastic scattering needed for proton polarimetry, it also provides some significant information about the spin dependence of dominant Regge poles. Most notably, the data indicates that the Pomeron has a significant spin-flip coupling. This allows the exploration of the double spin flip asymmetry A_{NN} for which some data over a wide energy range is now available, along with a concrete realization of a proposed Odderon search.Comment: final reference modife

    New 26P(p,{\gamma})27S thermonuclear reaction rate and its astrophysical implication in rp-process

    Full text link
    Accurate nuclear reaction rates for 26P(p,{\gamma})27S are pivotal for a comprehensive understanding of rp-process nucleosynthesis path in the region of proton-rich sulfur and phosphorus isotopes. However, large uncertainties still exist in the current rate of 26P(p,{\gamma})27S because of the lack of the nuclear mass and the energy level structure information of 27S. We reevaluate this reaction rate using the experimentally constrained 27S mass, together with the shell-model predicted level structure. It is found that the 26P(p,{\gamma})27S reaction rate is dominated by a direct-capture (DC) reaction mechanism despite the presence of three resonances at E = 1.104, 1.597, 1.777 MeV above the proton threshold in 27S. The new rate is overall smaller than the other previous rates from Hauser-Feshbach statistical model by at least one order of magnitude in the temperature range of X-ray burst interest. In addition, we consistently update the photodisintegration rate using the new 27S mass. The influence of new rates of forward and reverse reaction in the abundances of isotopes produced in rp-process is explored by post-processing nucleosynthesis calculations. The final abundance ratio of 27S/26P obtained using the new rates is only 10% of that from the old rate. The abundance flow calculations show the reaction path 26P(p,{\gamma})27S(\b{eta}+,{\nu})27P is not as important as thought previously for producing 27P. The adoption of the new reaction rates for 26P(p,{\gamma})27S only reduces the final production of aluminum by 7.1%, and has no discernible impact on the yield of other elements

    Assessing depleted uranium (DU) contamination of soil, plants and earthworms at UK weapons testing sites

    Get PDF
    Depleted uranium (DU) weapons testing programmes have been conducted at two locations within the UK. An investigation was therefore carried out to assess the extent of any environmental contamination arising from these test programmes using both alpha spectrometry and mass spectrometry techniques. Uranium isotopic signatures indicative of DU contamination were observed in soil, plant and earthworm samples collected in the immediate vicinity of test firing points and targets, but contamination was found to be localised to these areas. The paper demonstrates the superiority of the 235U:238U ratio over the 234U:238U ratio for identifying and quantifying DU contamination in environmental samples and also describes the respective circumstances under which alpha spectrometry or mass spectrometry may be the more appropriate analytical tool
    • 

    corecore