347 research outputs found
The baryonic Y-shape confining potential energy and its approximants
We discuss the validity of replacing the complicated three-body confinement
operator of the Y string junction type by three kinds of approximation which
are numerically much simpler to handle: a one-body operator with the junction
point at the centre of mass, a two-body operator corresponding to half the
perimeter of the triangle formed by the three particles, and the average of
both. Two different approaches for testing the quality of the approximations
are proposed: a geometrical treatment based on the comparison of the potential
energy strengths for the various inter quark distances, and a dynamical
treatment based on the comparison of the corresponding effective string
tensions using a hyperspherical approach. Both procedures give very similar
results. It is shown how to simulate the genuine string junction operator by
the approximations proposed above. Exact three-body calculations are presented
in order to compare quantitatively the various approximations and to confirm
our analysis.Comment: 28 pages, 5 figures, submitted to EPJ
Generating multimedia presentations: from plain text to screenplay
In many Natural Language Generation (NLG) applications, the output is limited to plain text – i.e., a string of words with punctuation and paragraph breaks, but no indications for layout, or pictures, or dialogue. In several projects, we have begun to explore NLG applications in which these extra media are brought into play. This paper gives an informal account of what we have learned. For coherence, we focus on the domain of patient information leaflets, and follow an example in which the same content is expressed first in plain text, then in formatted text, then in text with pictures, and finally in a dialogue script that can be performed by two animated agents. We show how the same meaning can be mapped to realisation patterns in different media, and how the expanded options for expressing meaning are related to the perceived style and tone of the presentation. Throughout, we stress that the extra media are not simple added to plain text, but integrated with it: thus the use of formatting, or pictures, or dialogue, may require radical rewording of the text itself
Pentaquarks in string dynamics
The masses of , , and pentaquarks are
evaluated in a framework of both the Effective Hamiltonian approach to QCD and
spinless Salpeter using the Jaffe-Wilczek diquark approximation and the string
interaction for the diquark-diquark-antiquark system. The masses of the light
pentaquarks are found to be in the region above 2 GeV. The similar calculations
yield the mass of pentaquark 3250 MeV and
pentaquark 6509 MeV.Comment: 5 pages. Based on talk by I.M.Narodetskii at BEACH 2004, 6th
International Conference on Hyperons, Charm and Beauty Hadrons, Illionois
Institute of Technology, Chicago, June. 27 - July 3, 2004. Typos correcte
Pentaquarks in the Jaffe-Wilczek approximation
The masses of , and pentaquarks are
evaluated in a framework of both the Effective Hamiltonian approach to QCD and
spinless Salpeter using the Jaffe--Wilczek diquark approximation and the string
interaction for the diquark--diquark--antiquark system. The pentaquark masses
are found to be in the region above 2 GeV. That indicates that the Goldstone
boson exchange effects may play an important role in the light pentaquarks. The
same calculations yield the mass of pentaquark 3250 MeV
and pentaquark 6509 MeV.Comment: 14 pages, 2 tables, LaTeX2e. References correcte
Baryon spectra with instanton induced forces
Except the vibrational excitations of and mesons, the main features
of spectra of mesons composed of quarks , , and can be quite well
described by a semirelativistic potential model including instanton induced
forces. The spectra of baryons composed of the same quarks is studied using the
same model. The results and the limitations of this approach are described.
Some possible improvements are suggested.Comment: 5 figure
Can minimalism about truth embrace polysemy?
Paul Horwich is aware of the fact that his theory as stated in his works is directly applicable only to a language in which a word, understood as a syntactic type, is connected with exactly one literal meaning. Yet he claims that the theory is expandable to include homonymy and indexicality and thus may be considered as applicable to natural language. My concern in this paper is with yet another kind of ambiguity - systematic polysemy - that assigns multiple meanings to one linguistic type. I want to combine the characteristics of systematic polysemy with the Kaplanian insight that meanings of expressions may be defined by semantic rules which assign content in context and to ask the question if minimalism about truth and meaning is compatible with such rule-based systematic polysemy. I will first explain why the expressions that exhibit rule-based systematic polysemy are difficult to combine with a truth theory that is based on a use theory of meaning before proceeding to argue that indexicals and proper names are such expressions
Accuracy of Auxiliary Field Approach for Baryons
We provide a check of the accuracy of the auxiliary field formalism used to
derive the Effective Hamiltonian for baryons in the Field Correlator Method. To
this end we compare the solutions for the Effective Hamiltonian with those
obtained from the solution of the Salpeter equation. Comparing these results
gives a first estimate of the systematic uncertainty due to the use of the
auxiliary field formalism for baryons.Comment: 6 pages, 2 tables; published versio
E-readers and the death of the book: or, new media and the myth of the disappearing medium
The recent emergence of e-readers and e-books has b
rought the death of the book to the centre of
current debates on new media. In this article, we a
nalyse alternative narratives that surround the
possibility of the disappearance of print books, do
minated by fetishism, fears about the end of
humanism, and ideas of techno-fundamentalist progre
ss. We argue that, in order to comprehend
such narratives, we need to inscribe them in the br
oader history of media. The emergence of new
media, in fact, has often been accompanied by narra
tives about the possible disappearance of
older media: the introduction of television, for in
stance, inspired claims about the forthcoming
death of film and radio. As a recurrent narrative s
haping the reception of media innovation, the
myth of the disappearing medium helps us to make se
nse of the transformations that media
change provokes in our everyday life
International demands for austerity: examining the impact of the IMF on the public sector
What effects do International Monetary Fund (IMF) loans have on borrow-ing countries? Even after decades of research, no consensus exists. We offer a straight-forward explanation for the seemingly mixed effects of IMF loans. We argue thatdifferent loans have different effects because of the varied conditions attached to IMFfinancing. To demonstrate this point, we investigate IMF loans with and withoutconditions that require public sector reforms in exchange for financing. We find thatthe addition of a public sector reform condition to a country’s IMF program signifi-cantly reduces government spending on the public sector wage bill. This evidencesuggest that conditions are a key mechanism linking IMF lending to policy outcomes.Although IMF loans with public sector conditions prompt cuts to the wage bill in theshort-term, these cuts do not persist in the longer-term. Borrowers backslide oninternationally mandated spending cuts in response to domestic political pressures
Pot, kettle: Nonliteral titles aren’t (natural) science
© 2020 The Author. Published by MIT Press. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1162/qss_a_00078Researchers may be tempted to attract attention through poetic titles for their publications,
but would this be mistaken in some fields? Whilst poetic titles are known to be common in
medicine, it is not clear whether the practice is widespread elsewhere. This article
investigates the prevalence of poetic expressions in journal article titles 1996-2019 in 3.3
million articles from all 27 Scopus broad fields. Expressions were identified by manually
checking all phrases with at least 5 words that occurred at least 25 times, finding 149 stock
phrases, idioms, sayings, literary allusions, film names and song titles or lyrics. The
expressions found are most common in the social sciences and the humanities. They are also
relatively common in medicine, but almost absent from engineering and the natural and
formal sciences. The differences may reflect the less hierarchical and more varied nature of
the social sciences and humanities, where interesting titles may attract an audience. In
engineering, natural science and formal science fields, authors should take extra care with
poetic expressions, in case their choice is judged inappropriate. This includes interdisciplinary
research overlapping these areas. Conversely, reviewers of interdisciplinary research
involving the social sciences should be more tolerant of poetic licens
- …