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Search Results: 1 - 10 of 219686 matches for " C. Plant "
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$ρ\to 4π$ in chirally symmetric models
Robert S. Plant,Michael C. Birse
Physics , 1995, DOI: 10.1016/0370-2693(95)01273-7
Abstract: The decays $\rho^0\to 2\pi^+2\pi^-$ and $\rho^0\to 2\pi^0\pi^+\pi^-$ are studied using various effective Lagrangians for $\pi$ and $\rho$ (and in some cases $a_1$) mesons, all of which respect the approximate chiral symmetry of the strong interaction. Partial widths of the order of 1 keV or less are found in all cases. These are an order of magnitude smaller than recent predictions based on non-chiral models.
Meson properties in an extended nonlocal NJL model
Robert S. Plant,Michael C. Birse
Physics , 1997, DOI: 10.1016/S0375-9474(97)00635-0
Abstract: We consider a nonlocal version of the NJL model, based on a separable quark-quark interaction. The interaction is extended to include terms that bind vector and axial-vector mesons. The nonlocality means that no further regulator is required. Moreover the model is able to confine the quarks by generating a quark propagator without poles at real energies. Working in the ladder approximation, we calculate amplitudes in Euclidean space and discuss features of their continuation to Minkowski energies. Conserved currents are constructed and we demonstrate their consistency with various Ward identities. Various meson masses are calculated, along with their strong and electromagnetic decay amplitudes. We also calculate the electromagnetic form factor of the pion, as well as form factors associated with the processes gamma gamma^* to pi^0 and omega to pi^0 gamma^*. The results are found to lead to a satisfactory phenomenology and lend some dynamical support to the idea of vector-meson dominance.
Mesonic fluctuations in a nonlocal Nambu-Jona-Lasinio model
Robert S. Plant,Michael C. Birse
Physics , 2000, DOI: 10.1016/S0375-9474(01)01669-4
Abstract: The effects of meson fluctuations are studied in a nonlocal generalization of the Nambu-Jona-Lasinio model, by including terms of next-to-leading order (NLO) in 1/N_c. In the model with only scalar and pseudoscalar interactions NLO contributions to the quark condensate are found to be very small. This is a result of cancellation between virtual mesons and Fock terms, which occurs for the parameter sets of most interest. In the quark self-energy, similar cancellations arise in the tadpole diagrams, although not in other NLO pieces which contribute at the \sim 25% level. The effects on pion properties are also found to be small. NLO contributions from real $\pi\pi$ intermediate states increase the sigma meson mass by $\sim 30%$. In an extended model with vector and axial interactions, there are indications that NLO effects could be larger.
Is John’s Gospel Ethically Defective?
Robin Plant
Kairos : Evangelical Journal of Theology , 2012,
Abstract: This paper discusses and evaluates the widespread view that John’s Gospel has little ethical value and may even be responsible for fostering antisemitism. It is argued that such criticisms are misplaced and that John is, in fact, advocating the kind of unity, mutual trust and self-sacrifice that would have been necessary among believers at a time of conflict between church and synagogue. Jesus’ willingness to wash the disciples’ feet, the egalitarian nature of the Gospel, and the paradigmatic community of Father, Son and Spirit, are identified as role models for the kind of love Jesus commands. Although John’s ethical focus is essentially inward-looking, it forms the basis for a distinctive Christian counter-culture and has important social and political implications. It is concluded that while John’s ethical vision is limited, and open to being misapplied, this can be avoided by interpreting it in the light of other biblical perspectives.
Celebrating the Ascension
Robin Plant
Kairos : Evangelical Journal of Theology , 2011,
Abstract:
Selection of Spatiotemporal Features in Breast MRI to Differentiate between Malignant and Benign Small Lesions Using Computer-Aided Diagnosis
F. Steinbruecker,A. Meyer-Baese,C. Plant,T. Schlossbauer,U. Meyer-Baese
Advances in Artificial Neural Systems , 2012, DOI: 10.1155/2012/919281
Abstract: Automated detection and diagnosis of small lesions in breast MRI represents a challenge for the traditional computer-aided diagnosis (CAD) systems. The goal of the present research was to compare and determine the optimal feature sets describing the morphology and the enhancement kinetic features for a set of small lesions and to determine their diagnostic performance. For each of the small lesions, we extracted morphological and dynamical features describing both global and local shape, and kinetics behavior. In this paper, we compare the performance of each extracted feature set for the differential diagnosis of enhancing lesions in breast MRI. Based on several simulation results, we determined the optimal feature number and tested different classification techniques. The results suggest that the computerized analysis system based on spatiotemporal features has the potential to increase the diagnostic accuracy of MRI mammography for small lesions and can be used as a basis for computer-aided diagnosis of breast cancer with MR mammography. 1. Introduction Breastcancer is one of the most common cancers among women. Contrast-enhanced MR imaging of the breast was reported to be a highly sensitive method for the detection of invasive breast cancer [1]. Different investigators described that certain dynamic signal intensity (SI) characteristics (rapid and intense contrast enhancement followed by a wash out phase) obtained in dynamic studies are a strong indicator for malignancy [2]. Morphologic criteria have also been identified as valuable diagnostic tools [3]. Recently, combinations of different dynamic and morphologic characteristics have been reported [4] that can reach diagnostic sensitivities up to 97 and specificities up to 76.5 . As an important aspect remains the fact that many of these techniques were applied on a database of predominantly tumors of a size larger than 2?cm. In these cases, MRI reaches a very high sensitivity in the detection of invasive breast cancer due to both morphological criteria as well as characteristic time-signal intensity curves. However, the value of dynamic MRI and of automatic identification and classification of characteristic kinetic curves is not well established in small lesions when clinical findings, mammography, and ultrasound are unclear. Recent clinical research has shown that DCIS with small invasive carcinoma can be adequately visualized in MRI [5] and that MRI provides an accurate estimation of invasive breast cancer tumor size, especially in tumors of 2?cm or smaller [6]. Visual assessment of
Measurements of nitrite production and nitrite-producing organisms in and around the primary nitrite maximum in the central California Current
A. E. Santoro,C. M. Sakamoto,J. M. Smith,J. N. Plant
Biogeosciences Discussions , 2013, DOI: 10.5194/bgd-10-5803-2013
Abstract: Nitrite (NO2–) is a substrate for both oxidative and reductive microbial metabolism. NO2– accumulates at the base of the euphotic zone in oxygenated, stratified open ocean water columns, forming a feature known as the primary nitrite maximum (PNM). Potential pathways of NO2– production include the oxidation of ammonia (NH3) by ammonia-oxidizing bacteria or archaea and assimilatory nitrate (NO3–) reduction by phytoplankton or heterotrophic bacteria. Measurements of NH3 oxidation and NO3– reduction to NO2– were conducted at two stations in the central California Current in the eastern North Pacific to determine the relative contributions of these processes to NO2– production in the PNM. Sensitive (< 10 nmol L 1), high-resolution measurements of [NH4+] and [NO2–] indicated a persistent NH4+ maximum overlying the PNM at every station, with concentrations as high as 1.5 μmol L 1. Within and just below the PNM, NH3 oxidation was the dominant NO2– producing process with rates of NH3 oxidation of up to 50 nmol L 1 d 1, coinciding with high abundances of ammonia-oxidizing archaea. Though little NO2– production from NO3– was detected, potentially nitrate-reducing phytoplankton (photosynthetic picoeukaryotes, Synechococcus, and Prochlorococcus) were present at the depth of the PNM. Rates of NO2– production from NO3– were highest within the upper mixed layer (4.6 nmol L 1 d 1) but were either below detection limits or 10 times lower than NH3 oxidation rates around the PNM. One-dimensional modeling of water column NO2– profiles supported direct rate measurements of a net biological sink for NO2– just below the PNM. Residence time estimates of NO2– within the PNM were similar at the mesotrophic and oligotrophic stations and ranged from 150–205 d. Our results suggest the PNM is a dynamic, rather than relict, feature with a source term dominated by ammonia oxidation.
Altering SARS Coronavirus Frameshift Efficiency Affects Genomic and Subgenomic RNA Production
Ewan P. Plant,Amy C. Sims,Ralph S. Baric,Jonathan D. Dinman,Deborah R. Taylor
Viruses , 2013, DOI: 10.3390/v5010279
Abstract: In previous studies, differences in the amount of genomic and subgenomic RNA produced by coronaviruses with mutations in the programmed ribosomal frameshift signal of ORF1a/b were observed. It was not clear if these differences were due to changes in genomic sequence, the protein sequence or the frequency of frameshifting. Here, viruses with synonymous codon changes are shown to produce different ratios of genomic and subgenomic RNA. These findings demonstrate that the protein sequence is not the primary cause of altered genomic and subgenomic RNA production. The synonymous codon changes affect both the structure of the frameshift signal and frameshifting efficiency. Small differences in frameshifting efficiency result in dramatic differences in genomic RNA production and TCID50 suggesting that the frameshifting frequency must stay above a certain threshold for optimal virus production. The data suggest that either the RNA sequence or the ratio of viral proteins resulting from different levels of frameshifting affects viral replication.
Influenza pandemic preparedness: motivation for protection among small and medium businesses in Australia
Rochelle E Watkins, Feonagh C Cooke, Robert J Donovan, C Raina MacIntyre, Ralf Itzwerth, Aileen J Plant
BMC Public Health , 2007, DOI: 10.1186/1471-2458-7-157
Abstract: Semi-structured face-to-face interviews were conducted with 201 small and medium business owners or managers in New South Wales and Western Australia. Eligible small or medium businesses were defined as those that had less than 200 employees. Binomial logistic regression analysis was used to identify the predictors of having considered the impact of, having a plan for, and needing help to prepare for pandemic influenza.Approximately 6 per cent of participants reported that their business had a plan for pandemic influenza, 39 per cent reported that they had not thought at all about the impact of pandemic influenza on their business, and over 60 per cent stated that they required help to prepare for a pandemic. Beliefs about the severity of pandemic influenza and the ability to respond were significant independent predictors of having a plan for pandemic influenza, and the perception of the risk of pandemic influenza was the most important predictor of both having considered the impact of, and needing help to prepare for a pandemic.Our findings suggest that small and medium businesses in Australia are not currently well prepared for pandemic influenza. We found that beliefs about the risk, severity, and the ability to respond effectively to the threat of pandemic influenza are important predictors of preparedness. Campaigns targeting small and medium businesses should emphasise the severity of the consequences to their businesses if a pandemic were to occur, and, at the same time, reassure them that there are effective strategies capable of being implemented by small and medium businesses to deal with a pandemic.Since late 2005 the risk of pandemic influenza and the need for preparedness have featured reasonably frequently in the news media in Australia, often associated with overseas reports of large outbreaks of infection among birds or small clusters of infection among humans. Strategic plans have been prepared for an outbreak of pandemic influenza associated with
Orientación profesional en dinamarca: El control social con ?guantes de seda?
Plant,Peter; Thomsen,Rie;
Orientaci?3n y sociedad , 2011,
Abstract: career guidance in denmark is well organised, highly structured, and professionalised. this mirrors the strong policy focus on the role of guidance as a soft societal steering instrument. with this backdrop , the dilemma in danish guidance is the delicate balance between guidance as an instrument for personal development, and guidance as social control.
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