514 research outputs found
Systematics of q anti-q states in the (n,M^2) and (J,M^2) planes
In the mass region up to M < 2400 MeV we systematise mesons on the plots
(n,M^2) and (J,M^2), thus setting their classification in terms of n^{2S+1}L_J
q anti-q states. The trajectories on the (n,M^2)-plots are drawn for the
following (IJ^{PC})-states: a_0(10^{++}), a_1(11^{++}), a_2(12^{++}),
a_3(13^{++}), a_4(14^{++}), pi(10^{-+}), pi_2(12^{-+}), eta(00^{-+}),
eta_2(02^{-+})$, rho(11^{--}), f_0(00^{++}), f_2(02^{++}). All trajectories are
linear, with nearly the same slopes. At the (J,M^2)-plot we set out meson
states for leading and daughter trajectories: for pi, rho, a_1, a_2 and P'.Comment: 6 pages, LaTeX, 16 EPS figures, epsfig.st
Systematization of tensor mesons and the determination of the glueball
It is shown that new data on the -resonances in the mass
range MeV support the linearity of the -trajectories,
where is the radial quantum number of quark--antiquark state. In this way
all vacancies for the isoscalar tensor -mesons in the range up to 2450
MeV are filled in. This allows one to fix the broad -state with
MeV and MeV as the lowest tensor glueball. PACS
numbers: 14.40.-n, 12.38.-t, 12.39.-MkComment: 10 pages, 1 figur
Formation of the internal structure of solids under severe action
On the example of a particular problem, the theory of vacancies, a new form
of kinetic equations symmetrically incorporation the internal and free energies
has been derived. The dynamical nature of irreversible phenomena at formation
and motion of defects (dislocations) has been analyzed by a computer
experiment. The obtained particular results are extended into a thermodynamic
identity involving the law of conservation of energy at interaction with an
environment (the 1st law of thermodynamics) and the law of energy
transformation into internal degree of freedom (relaxation). The identity is
compared with the analogous Jarzynski identity. The approach is illustrated by
simulation of processes during severe plastic deformation, the Rybin kinetic
equation for this case has been derived.Comment: 9 pages, 5 figure
Meson-meson scattering within one loop Chiral Perturbation Theory and its unitarization
We present the complete one-loop calculation of all the two meson scattering
amplitudes within the framework of SU(3) Chiral Perturbation Theory, which
includes pions, kaons and the eta. In addition, we have unitarized these
amplitudes with the coupled channel Inverse Amplitude Method, which ensures
simultaneously the good low energy properties of Chiral Perturbation Theory and
unitarity. We show how this method provides a remarkable description of
meson-meson scattering data up to 1.2 GeV including the scattering lengths and
the generation of seven light resonances, which is consistent with previous
determination of the chiral parameters. Particular attention is paid to discuss
the differences and similarities of this work with previous analysis in the
literature.Comment: 20 pages, 5 figures. Comments on sigma, kappa and eta', as well as
some references added. Final version to appear in Phys.Rev.
Non-Equilibrium Evolution Thermodynamics Theory
Alternative approach for description of the non-equilibrium phenomena arising
in solids at a severe external loading is analyzed. The approach is based on
the new form of kinetic equations in terms of the internal and modified free
energy. It is illustrated by a model example of a solid with vacancies, for
which there is a complete statistical ground. The approach is applied to the
description of important practical problem - the formation of fine-grained
structure of metals during their treatment by methods of severe plastic
deformation. In the framework of two-level two-mode effective internal energy
potential model the strengthening curves unified for the whole of deformation
range and containing the Hall-Petch and linear strengthening sections are
calculated.Comment: 7 pages, 1 figur
Deficient prefrontal attentional control in late-life generalized anxiety disorder: an fMRI investigation
Younger adults with anxiety disorders are known to show an attentional bias toward negative information. Little is known regarding the role of biased attention in anxious older adults, and even less is known about the neural substrates of any such bias. Functional magnetic resonance imaging (fMRI) was used to assess the mechanisms of attentional bias in late life by contrasting predictions of a top-down model emphasizing deficient prefrontal cortex (PFC) control and a bottom-up model emphasizing amygdalar hyperreactivity. In all, 16 older generalized anxiety disorder (GAD) patients (mean age=66 years) and 12 non-anxious controls (NACs; mean age=67 years) completed the emotional Stroop task to assess selective attention to negative words. Task-related fMRI data were concurrently acquired. Consistent with hypotheses, GAD participants were slower to identify the color of negative words relative to neutral, whereas NACs showed the opposite bias, responding more quickly to negative words. During negative words (in comparison with neutral), the NAC group showed PFC activations, coupled with deactivation of task-irrelevant emotional processing regions such as the amygdala and hippocampus. By contrast, GAD participants showed PFC decreases during negative words and no differences in amygdalar activity across word types. Across all participants, greater attentional bias toward negative words was correlated with decreased PFC recruitment. A significant positive correlation between attentional bias and amygdala activation was also present, but this relationship was mediated by PFC activity. These results are consistent with reduced prefrontal attentional control in late-life GAD. Strategies to enhance top-down attentional control may be particularly relevant in late-life GAD treatment
Recommended from our members
The use of phylogeny to interpret cross-cultural patterns in plant use and guide medicinal plant discovery: an example from Pterocarpus (Leguminosae)
The study of traditional knowledge of medicinal plants has led to discoveries that have helped combat diseases and improve healthcare. However, the development of quantitative measures that can assist our quest for new medicinal plants has not greatly advanced in recent years. Phylogenetic tools have entered many scientific fields in the last two decades to provide explanatory power, but have been overlooked in ethnomedicinal studies. Several studies show that medicinal properties are not randomly distributed in plant phylogenies, suggesting that phylogeny shapes ethnobotanical use. Nevertheless, empirical studies that explicitly combine ethnobotanical and phylogenetic information are scarce.In this study, we borrowed tools from community ecology phylogenetics to quantify significance of phylogenetic signal in medicinal properties in plants and identify nodes on phylogenies with high bioscreening potential. To do this, we produced an ethnomedicinal review from extensive literature research and a multi-locus phylogenetic hypothesis for the pantropical genus Pterocarpus (Leguminosae: Papilionoideae). We demonstrate that species used to treat a certain conditions, such as malaria, are significantly phylogenetically clumped and we highlight nodes in the phylogeny that are significantly overabundant in species used to treat certain conditions. These cross-cultural patterns in ethnomedicinal usage in Pterocarpus are interpreted in the light of phylogenetic relationships.This study provides techniques that enable the application of phylogenies in bioscreening, but also sheds light on the processes that shape cross-cultural ethnomedicinal patterns. This community phylogenetic approach demonstrates that similar ethnobotanical uses can arise in parallel in different areas where related plants are available. With a vast amount of ethnomedicinal and phylogenetic information available, we predict that this field, after further refinement of the techniques, will expand into similar research areas, such as pest management or the search for bioactive plant-based compounds
- …