1,132 research outputs found
A test of the instanton vacuum chiral quark model with axial anomaly low-energy theorems
The QCD + QED axial anomaly low-energy theorems are applied to estimate the
accuracy of an instanton vacuum - based chiral quark model. The low-energy
theorems give an exact relation between the matrix elements of the gluon and
photon parts of the QCD + QED axial anomaly operator equation. The matrix
elements between vacuum and two photon states and between vacuum and two gluon
states are calculated for arbitrary N_f. It is shown that this model does
satisfy the low-energy theorems with an accuracy of . We estimate
also the contribution of the nonperturbative conversion of gluons into photons
to the decay and compare with experimental data.Comment: uudecode, gzip, latex, 11 pages, the text and the list of references
was slightly change
A test of the instanton vacuum with low-energy theorems of the axial anomaly
We revisit the QCD+QED axial anomaly low-energy theorems which give an exact
relation between the matrix elements of the gluon and photon parts of the axial
anomaly operator equation within the framework of the {\em effective action}
derived from the instanton vacuum. The matrix elements between the vacuum and
two photon states and between the vacuum and two gluon states are investigated
for arbitrary in the chiral limit. Having gauged the effective action
properly, we show that the model does exactly satisfy the low-energy theorems.Comment: 9 pages, no figure, final version which will appear in Phys. Lett.
Preasymptotic nature of hadron scattering vs small-x HERA Data
We emphasize that recently observed regularities in hadron interactions and
deep-inelastic scattering are of preasymptotic nature and it is impossible to
make conclusions on the true asymptotic behavior of observables without
unitarization procedure. Unitarization is important and changes scattering
picture drastically.Comment: LaTeX file, 9 pages; 4 tarred, gzipped and uuencoded figures in a
separate fil
Generating socially appropriate tutorial dialog
Analysis of student-tutor coaching dialogs suggest that good human tutors attend to and attempt to influence the motivational state of learners. Moreover, they are sensitive to the social face of the learner, and seek to mitigate the potential face threat of their comments. This paper describes a dialog generator for pedagogical agents that takes motivation and face threat factors into account. This enables the agent to interact with learners in a socially appropriate fashion, and foster intrinsic motivation on the part of the learner, which in turn may lead to more positive learner affective states
Granulocyte concentrates: Prolonged functional capacity during storage in the presence of phenotypic changes
Background Granulocyte transfusion has been proposed as a bridging therapy for patients with prolonged p
School Direct, a policy for initial teacher training in England: plotting a principled pedagogical path through a changing landscape
This paper explores the role of teacher educators in schools and universities in England and the changes that have arisen within the field of Initial Teacher Training (ITT) as a result of the Coalition governmentâs (2010 onwards) School Direct initiative. The discussion which follows and the conclusions suggested are live, current and of pivotal interest to all universities with ITT programmes, as well as all schools involved in the delivery of ITT, and all parties with a policy interest in the supply of effective teacher education. After setting the context, the discussion starts with a critical examination of ITT policy in England over the course of the last 20 years. We then consider troubling binaries inherent in teacher education and go on to explore insights from research: the importance of beliefs; the problem of enactment; the theory/practice divide. These are then used to craft the enabling constraints for third-space activity designed to set in motion a hybridisation process from which a new breed of teacher educator could emerge. We suggest that university and school colleagues working together in collaborative partnership can provide a principled pedagogical path through a changing landscape of education policy
Deep exclusive electroproduction off the proton at CLAS
The exclusive electroproduction of above the resonance region was
studied using the Large Acceptance Spectrometer () at
Jefferson Laboratory by scattering a 6 GeV continuous electron beam off a
hydrogen target. The large acceptance and good resolution of ,
together with the high luminosity, allowed us to measure the cross section for
the process in 140 (, , ) bins:
, 1.6 GeV GeV and 0.1 GeV
GeV. For most bins, the statistical accuracy is on the order of a few
percent. Differential cross sections are compared to two theoretical models,
based either on hadronic (Regge phenomenology) or on partonic (handbag diagram)
degrees of freedom. Both can describe the gross features of the data reasonably
well, but differ strongly in their ingredients. If the handbag approach can be
validated in this kinematical region, our data contain the interesting
potential to experimentally access transversity Generalized Parton
Distributions.Comment: 18pages, 21figures,2table
A next step in disruption management: combining operations research and complexity science
Railway systems occasionally get into a state of being out-of-control, meaning that barely any train is running, even though the required resources (infrastructure, rolling stock and crew) are available. Because of the large number of affected resources and the absence of detailed, timely and accurate information, currently existing disruption management techniques cannot be applied in out-of-control situations. Most of the contemporary approaches assume that there is only one single disruption with a known duration, that all information about the resources is available, and that all stakeholders in the operations act as expected. Another limitation is the lack of knowledge about why and how disruptions accumulate and whether this process can be predicted. To tackle these problems, we develop a multidisciplinary framework combining techniques from complexity science and operations research, aiming at reducing the impact of these situations and-if possible-avoiding them. The key elements of this framework are (i) the generation of early warning signals for out-of-control situations, (ii) isolating a specific region such that delay stops propagating, and (iii) the application of decentralized decision making, more suited for information-sparse out-of-control situations
Hadronic Mass Spectrum Analysis of D+ into K- pi+ mu+ nu Decay and Measurement of the K*(892)^0 Mass and Width
We present a Kpi mass spectrum analysis of the four-body semileptonic charm
decay D+ into K- pi+ mu+ nu in the range of 0.65 GeV < mKpi < 1.5 GeV. We
observe a non-resonant contribution of 5.30 +- 0.74 +0.99 -0.51 % with respect
to the total D+ into K- pi+ mu+ nu decay. For the K*(892)^0 resonance, we
obtain a mass of 895.41 +- 0.32 +0.35 -0.36 MeV, a width of 47.79 +- 0.86 +1.3
-1.1 MeV, and a Blatt-Weisskopf damping factor parameter of 3.96 +- 0.54 +0.72
-0.90 GeV^(-1). We also report 90 % CL upper limits of 4 % and 0.64 % for the
branching ratios of D+ into K*(1680)^0 mu+ nu with respect to D+ into K- pi+
mu+ nu and D+ into K*(1430)^0 mu+ nu with respect to D+ into K- pi+ mu+ nu,
respectively.Comment: 14 page
âIt's like giving him a piece of me.â: Exploring UK and Israeli women's accounts of motherhood and feeding
Objective The present study explored how Israeli and UK mothers integrate feeding into their conceptualisations of mothering 2â6 months post-partum. Background The nature and importance of motherhood is subject to differential contextual, cultural, political and historical influences. We set out to compare experiences of motherhood and feeding between these two countries using a qualitative approach. Methods Forty one women (mean age 36.4 ± 2.7 years) from Israel and the UK, mostly married or in a committed relationship were interviewed about their experience of pregnancy, motherhood and feeding. Data were analysed thematically. Results The experience of motherhood in the early postnatal period was dominated, for all mothers, by the experience of breastfeeding and clustered around three representations of mothering, namely; 1) a devoted mother who ignores her own needs; 2) a mother who is available for her infant but acknowledges her needs as well; and 3) a struggling mother for whom motherhood is a burden. Such representations existed within both cultural groups and sometimes coexisted within the same mothers. UK women described more struggles within motherhood whereas a tendency towards idealising motherhood was observed for Israeli women. Conclusion There are similarities in the ways that UK and Israeli women experienced motherhood and feeding. Where family life is strongly emphasized, mothers reported extremes of idealism and burden and associated an âidealâ mother with a breastfeeding mother. Where motherhood is represented as just one of many roles women take up, they are more likely to represent a âgood enoughâ approach to mothering. Understanding the experience of motherhood and feeding in different cultural settings is important to provide the context for postnatal care specifically where mothers are reluctant to share problems or difficulties encountered
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