1,566 research outputs found
Properties of Light Flavour Baryons in Hypercentral quark model
The light flavour baryons are studied within the quark model using the hyper
central description of the three-body system. The confinement potential is
assumed as hypercentral coulomb plus power potential () with power
index . The masses and magnetic moments of light flavour baryons are
computed for different power index, starting from 0.5 to 1.5. The
predicted masses and magnetic moments are found to attain a saturated value
with respect to variation in beyond the power index 1.0. Further
we computed transition magnetic moments and radiative decay width of light
flavour baryons. The results are in good agreement with known experimental as
well as other theoretical models.Comment: Accepted in Pramana J. of Physic
Antikaon production in nucleon-nucleon reactions near threshold
The antikaon production cross section from nucleon-nucleon reactions near
threshold is studied in a meson exchange model. We include both pion and kaon
exchange, but neglect the interference between the amplitudes. In case of pion
exchange the antikaon production cross section can be expressed in terms of the
antikaon production cross section from a pion-nucleon interaction, which we
take from the experimental data if available. Otherwise, a -resonance
exchange model is introduced to relate the different reaction cross sections.
In case of kaon exchange the antikaon production cross section is related to
the elastic and cross sections, which are again taken from
experimental measurements. We find that the one-meson exchange model gives a
satisfactory fit to the available data for the cross section
at high energies. We compare our predictions for the cross section near
threshold with an earlier empirical parameterization and that from phase space
models.Comment: 16 pages, LaTeX, 5 postscript figures included, submitted to Z. Phys.
The phase diagram of Yang-Mills theory with a compact extra dimension
We present a non-perturbative study of the phase diagram of SU(2) Yang-Mills
theory in a five-dimensional spacetime with a compact extra dimension. The
non-renormalizable theory is regularized on an anisotropic lattice and
investigated through numerical simulations in a regime characterized by a
hierarchy between the scale of low-energy physics, the inverse compactification
radius, and the cutoff scale. We map out the structure of the phase diagram and
the pattern of lines corresponding to fixed values of the ratio between the
mass of the fifth component of the gauge field and the non-perturbative mass
gap of the four-dimensional modes. We discuss different limits of the model,
and comment on the implications of our findings.Comment: 17 pages, 9 figure
Counting and effective rigidity in algebra and geometry
The purpose of this article is to produce effective versions of some rigidity
results in algebra and geometry. On the geometric side, we focus on the
spectrum of primitive geodesic lengths (resp., complex lengths) for arithmetic
hyperbolic 2-manifolds (resp., 3-manifolds). By work of Reid, this spectrum
determines the commensurability class of the 2-manifold (resp., 3-manifold). We
establish effective versions of these rigidity results by ensuring that, for
two incommensurable arithmetic manifolds of bounded volume, the length sets
(resp., the complex length sets) must disagree for a length that can be
explicitly bounded as a function of volume. We also prove an effective version
of a similar rigidity result established by the second author with Reid on a
surface analog of the length spectrum for hyperbolic 3-manifolds. These
effective results have corresponding algebraic analogs involving maximal
subfields and quaternion subalgebras of quaternion algebras. To prove these
effective rigidity results, we establish results on the asymptotic behavior of
certain algebraic and geometric counting functions which are of independent
interest.Comment: v.2, 39 pages. To appear in Invent. Mat
Social marketing and healthy eating : Findings from young people in Greece
This document is the Accepted Manuscript version. The final publication is available at Springer via http://dx.doi.org/10.1007/s12208-013-0112-xGreece has high rates of obesity and non-communicable diseases owing to poor dietary choices. This research provides lessons for social marketing to tackle the severe nutrition-related problems in this country by obtaining insight into the eating behaviour of young adults aged 18–23. Also, the main behavioural theories used to inform the research are critically discussed. The research was conducted in Athens. Nine focus groups with young adults from eight educational institutions were conducted and fifty-nine participants’ views towards eating habits, healthy eating and the factors that affect their food choices were explored. The study found that the participants adopted unhealthier nutritional habits after enrolment. Motivations for healthy eating were good health, appearance and psychological consequences, while barriers included lack of time, fast-food availability and taste, peer pressure, lack of knowledge and lack of family support. Participants reported lack of supportive environments when deciding on food choices. Based on the findings, recommendations about the development of the basic 4Ps of the marketing mix, as well as of a fifth P, for Policy are proposedPeer reviewe
Single and two-particle energy gaps across the disorder-driven superconductor-insulator transition
The competition between superconductivity and localization raises profound
questions in condensed matter physics. In spite of decades of research, the
mechanism of the superconductor-insulator transition (SIT) and the nature of
the insulator are not understood. We use quantum Monte Carlo simulations that
treat, on an equal footing, inhomogeneous amplitude variations and phase
fluctuations, a major advance over previous theories. We gain new microscopic
insights and make testable predictions for local spectroscopic probes. The
energy gap in the density of states survives across the transition, but
coherence peaks exist only in the superconductor. A characteristic pseudogap
persists above the critical disorder and critical temperature, in contrast to
conventional theories. Surprisingly, the insulator has a two-particle gap scale
that vanishes at the SIT, despite a robust single-particle gap.Comment: 7 pages, 5 figures (plus supplement with 4 pages, 5 figures
Designed Azolopyridinium Salts Block Protective Antigen Pores In Vitro and Protect Cells from Anthrax Toxin
Background:Several intracellular acting bacterial protein toxins of the AB-type, which are known to enter cells by endocytosis, are shown to produce channels. This holds true for protective antigen (PA), the binding component of the tripartite anthrax-toxin of Bacillus anthracis. Evidence has been presented that translocation of the enzymatic components of anthrax-toxin across the endosomal membrane of target cells and channel formation by the heptameric/octameric PA63 binding/translocation component are related phenomena. Chloroquine and some 4-aminoquinolones, known as potent drugs against Plasmodium falciparium infection of humans, block efficiently the PA63-channel in a dose dependent way.Methodology/Principal Findings:Here we demonstrate that related positively charged heterocyclic azolopyridinium salts block the PA63-channel in the μM range, when both, inhibitor and PA63 are added to the same side of the membrane, the cis-side, which corresponds to the lumen of acidified endosomal vesicles of target cells. Noise-analysis allowed the study of the kinetics of the plug formation by the heterocycles. In vivo experiments using J774A.1 macrophages demonstrated that the inhibitors of PA63-channel function also efficiently block intoxication of the cells by the combination lethal factor and PA63 in the same concentration range as they block the channels in vitro.Conclusions/Significance:These results strongly argue in favor of a transport of lethal factor through the PA63-channel and suggest that the heterocycles used in this study could represent attractive candidates for development of novel therapeutic strategies against anthrax. © 2013 Beitzinger et al
Science Models as Value-Added Services for Scholarly Information Systems
The paper introduces scholarly Information Retrieval (IR) as a further
dimension that should be considered in the science modeling debate. The IR use
case is seen as a validation model of the adequacy of science models in
representing and predicting structure and dynamics in science. Particular
conceptualizations of scholarly activity and structures in science are used as
value-added search services to improve retrieval quality: a co-word model
depicting the cognitive structure of a field (used for query expansion), the
Bradford law of information concentration, and a model of co-authorship
networks (both used for re-ranking search results). An evaluation of the
retrieval quality when science model driven services are used turned out that
the models proposed actually provide beneficial effects to retrieval quality.
From an IR perspective, the models studied are therefore verified as expressive
conceptualizations of central phenomena in science. Thus, it could be shown
that the IR perspective can significantly contribute to a better understanding
of scholarly structures and activities.Comment: 26 pages, to appear in Scientometric
Therapeutic suggestion helps to cut back on drug intake for mechanically ventilated patients in intensive care unit
Research was conducted on ventilated patients treated in an intensive care unit (ICU) under identical circumstances; patients were divided into two groups (subsequently proved statistically identical as to age and Simplified Acute Physiology Score II [SAPS II]). One group was treated with positive suggestions for 15-20 min a day based on a predetermined scheme, but tailored to the individual patient, while the control group received no auxiliary psychological treatment. Our goal was to test the effects of positive communication in this special clinical situation. In this section of the research, the subsequent data collection was aimed to reveal whether any change in drug need could be demonstrated upon the influence of suggestions as compared to the control group. Owing to the strict recruitment criteria, a relatively small sample (suggestion group n = 15, control group n = 10) was available during the approximately nine-month period of research. As an outcome of suggestions, there was a significant drop in benzodiazepine (p < 0.005), opioid (p < 0.001), and the α2-agonist (p < 0.05) intake. All this justifies the presence of therapeutic suggestions among the therapies used in ICUs. However, repeating the trial on a larger sample of patients would be recommended. © 2013 Akadémiai Kiadó, Budapest
Study of the reaction e^{+}e^{-} -->J/psi\pi^{+}\pi^{-} via initial-state radiation at BaBar
We study the process with
initial-state-radiation events produced at the PEP-II asymmetric-energy
collider. The data were recorded with the BaBar detector at center-of-mass
energies 10.58 and 10.54 GeV, and correspond to an integrated luminosity of 454
. We investigate the mass
distribution in the region from 3.5 to 5.5 . Below 3.7
the signal dominates, and above 4
there is a significant peak due to the Y(4260). A fit to
the data in the range 3.74 -- 5.50 yields a mass value
(stat) (syst) and a width value (stat)(syst) for this state. We do not
confirm the report from the Belle collaboration of a broad structure at 4.01
. In addition, we investigate the system
which results from Y(4260) decay
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