1,854 research outputs found

    Turbulent heating in solar cosmic ray theory

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    The heating of minor ions in solar flares by wave-wave-particle interaction with Langmuir waves, or ion acoustic waves, can be described by a diffusion equation in velocity-space for the particle distribution function. The dependence of the heating on the ion charge and mass, and on the composition of the plasma, is examined in detail. It is found that the heating mechanisms proposed by Ibragimov and Kocharov cannot account for the enhanced abundances of heavy elements in the solar cosmic rays

    CP Violation in the B0B^{0} meson system with BaBar

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    The BABAR detector, at the PEP-II asymmetric B Factory at SLAC collected a sample of 32 million BBbar pairs whilst operating at energies near the Upsilon(4S) resonance between October 1999 and May 2001. An study of time-dependent CP-violating asymmetries in events where one neutral B meson is fully reconstructed in a final state containing charmonium produced the measurement sin2beta = 0.59 +- 0.14 (stat) +- 0.05 (syst), which constitutes an observation of CP violation in the B0 meson system at the 4 sigma level. Also presented are preliminary results from a study of CP violation in the decays B0 to pi+pi- and B0 to K+pi-

    An investigation into the proportional discharge of air from side outlets on a small-scale terminal ventilation duct

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    This investigation relates to a small-scale air duct of rectangular cross-section with variably sized rectangular apertures pitched evenly along one face of the duct. Measurements of air velocities were made mainly with a hot-wire anemometer and to a lesser extent with a pitot-static tube. Details are given of the calibration and use of these instruments together with an outline of the precautions which must be taken to ensure reliability of results. Aperture air flow patterns determined by the use of the hot-wire anemometer were found to be complex and dependent primarily on the interrelated factors of duct gauge static pressure, aperture size, and that fraction of the approaching air which escaped through an aperture. It was established that aperture air volume flow could be determined accurately from a single, half-height, horizontal traverse of an aperture with the hot-wire probe and consequently the expenditure of time and effort required for a multi-row traverse was eliminated. Some evidence was found to support the supposition that variation in the magnitude of the total duct air flow does not affect the proportions into which it is divided by fixed aperture settings. Relationships between non-dimensional parameters were determined from which a method was devised by which the requisite aperture areas associated with specified aperture proportional air flows were predicted

    The Motion of a Body in Newtonian Theories

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    A theorem due to Bob Geroch and Pong Soo Jang ["Motion of a Body in General Relativity." Journal of Mathematical Physics 16(1), (1975)] provides the sense in which the geodesic principle has the status of a theorem in General Relativity (GR). Here we show that a similar theorem holds in the context of geometrized Newtonian gravitation (often called Newton-Cartan theory). It follows that in Newtonian gravitation, as in GR, inertial motion can be derived from other central principles of the theory.Comment: 12 pages, 1 figure. This is the version that appeared in JMP; it is only slightly changed from the previous version, to reflect small issue caught in proo

    Epistasis and the sensitivity of phenotypic screens for beta thalassaemia

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    Genetic disorders of haemoglobin, particularly the sickle cell diseases and the alpha and beta thalassaemias, are the commonest inherited disorders worldwide. The majority of affected births occur in low-income and lower-middle income countries. Screening programmes are a vital tool to counter these haemoglobinopathies by: (i) identifying individual carriers and allowing them to make informed reproductive choices, and (ii) generating population level gene-frequency estimates, to help ensure the optimal allocation of public health resources. For both of these functions it is vital that the screen performed is suitably sensitive. One popular first-stage screening option to detect carriers of beta thalassaemia in low-income countries is the One Tube Osmotic Fragility Test (OTOFT). Here we introduce a population genetic framework within which to quantify the likely sensitivity and specificity of the OTOFT in different epidemiological contexts. We demonstrate that interactions between the carrier states for beta thalassaemia and alpha thalassaemia, glucose-6-phosphate dehydrogenase deficiency and Southeast Asian Ovalocytosis have the potential to reduce the sensitivity of OTOFTs for beta thalassaemia heterozygosity to below 70%. Our results therefore caution against the widespread application of OTOFTs in regions where these erythrocyte variants co-occur

    The Utilization of the STOP-Bang Questionnaire for Identification of Surgical Patients at Risk for Obstructive Sleep Apnea

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    Obstructive sleep apnea (OSA) is a breathing disorder that if left untreated during the perioperative period can lead to deleterious complications. Considering there remains a significant amount of Americans undiagnosed, it is of utmost importance that adult surgical patients undergoing elective procedures be appropriately screened to detect OSA risk in order to decrease adverse events through individualized interventions during the surgical phases. Polysomnography testing is the diagnostic standard, but its complexity in the perioperative setting renders it impractical. The STOP-Bang questionnaire is a validated screening tool that can be utilized as an alternative in this population to accurately identify at risk patients. At a local urban hospital in Pennsylvania, a data analytics team determined that a 1.6% annual compliance rate exists with this risk stratification tool amongst anesthesia providers. The aim of this quality improvement (QI) project is to increase overall compliance of the STOP-Bang questionnaire via incorporation into the preoperative nursing assessment and ultimately, increase detection of OSA risk in the undiagnosed surgical population at this healthcare institution. Post implementation data was analyzed and it was revealed that STOP-Bang compliance increased at an upwards of 62.2% over a 4ā€“week period. It was also shown that 14.8% of the surgical population was identified as intermediate to high-risk for OSA development. The STOP-Bang questionnaire is well documented for its reliability, precision, and ability to aid in provider identification of surgical patients at risk for OSA. Considering the specialized, individualized, and careful management OSA patients require to prevent perioperative complications, screening with the STOP-Bang questionnaire is recommended

    How important is the name in predicting false recognition for lookalike brands?

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    An underexploited role for psychology in trademark law is the testing of explicit or implicit judicial assumptions about consumer behavior. In this article we examine an assumption that is common across Commonwealth countries, namely, that similar packaging is unlikely to cause consumer confusion provided the brand names are dissimilar. We began by selecting branded products commonly found in supermarkets. For each existing brand we created 2 novel (fictitious) brands with highly similar packaging to the existing brand. One of these "lookalike" products had a similar name, the other a dissimilar name. Across 2 yes/no and 1 forced-choice experiments using photographs of the real and fictitious products we looked at false recognition rates. Contrary to the judicial assumption participants largely ignored the brand names when making their decisions based on memory. It was only when the pictures of the products were placed side-by-side (in the forced-choice task) that they paid the brand name any significant attention
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