3,416 research outputs found
Chiral Dynamics and the Low Energy Kaon-Nucleon Interaction
We examine the meson-baryon interaction in the strangeness S=-1 sector using
an effective chiral Lagrangian. Potentials are derived from this Lagrangian and
used in a coupled-channel calculation of the low energy observables. The
potentials are constructed such that in the Born approximation the s-wave
scattering amplitude is the same as that given by the effective chiral
Lagrangian, up to order . Comparison is made with the available low energy
hadronic data of the coupled system, which
includes the resonance, elastic and inelastic
scattering, and the threshold branching ratios of the decay. Good fits
to the experimental data and estimates of previously unknown Lagrangian
parameters are obtained.Comment: 20 pages, 10 postscript figures, uses revtex, e-mail addresses:
[email protected], [email protected],
[email protected]
Relation of fraternities to eductional institutions
Citation: Gasser, George W. Relation of fraternities to eductional institutions. Senior thesis, Kansas State Agricultural College, 1905.Morse Department of Special CollectionsIntroduciton: Whatever conclusion educators, and those who are being educated, may have reached, or lack of conclusion, this fact remains patent; fraternities have entered so vitally and so universally into the educational centers of the nation that their permanence is assured. True it is still a much mooted question in some colleges whether or not college fraternities should be allowed to exist and strong dissensions have arisen; but generally, though often gradually and insidiously, the fraternal organizations have won a permanent home. Excepting the military academies, West Point and Annapolis, where secret societies could not be tolerated by the government, Princeton and Vassar, of all the large eastern colleges, remain with doors closed to Greek letter societies. The typical home of these fraternities is in the eastern college and the time of their inception dates back to early American history. Like a good many other things, both good and bad, fraternities have been swept westward by the strong irresistible sweep of advanced civilization. Simply because fraternities have met strong and determined opposition is, of course, no proof that their dominant influence is evil. Primarily, merely an evidence of diverse opinions. However, the persistent, extended efforts to crush the movement give one a just reason to inquire into and find, if possible, whether or not such opposition is warranted
The anomalous chiral perturbation theory meson Lagrangian to order revisited
We present a revised and extended construction of the mesonic Lagrangian
density in chiral perturbation theory (ChPT) at order in the anomalous
(or epsilon) sector, . After improving several aspects
of the strategy we used originally, i.e., a more efficient application of
partial integration, the implementation of so-called Bianchi identities, and
additional trace relations, we find the new monomial sets to include 24
, 23 SU(3), and 5 SU(2) elements. Furthermore, we introduce 8
supplementary terms due to the extension of the chiral group to .Comment: 21 pages, Latex, using RevTe
Note on Strange Quarks in the Nucleon
Scalar matrix elements involving strange quarks are studied in several
models. Apart from a critical reexamination of results obtained in the Nambu
and Jona-Lasinio model we study a scenario, motivated by instanton physics,
where spontaneous chiral symmetry breaking is induced by the flavor-mixing 't
Hooft interaction only. We also investigate possible contributions of virtual
kaon loops to the strangeness content of the nucleon.Comment: 12 pages, latex style. One figure, available from the author upon
request. University of Regensburg TPR-94-0
Tv-RIO1 â an atypical protein kinase from the parasitic nematode Trichostrongylus vitrinus
Background: Protein kinases are key enzymes that regulate a wide range of cellular processes, including cell-cycle progression, transcription, DNA replication and metabolic functions. These enzymes catalyse the transfer of phosphates to serine, threonine and tyrosine residues, thus playing functional roles in reversible protein phosphorylation. There are two main groups, namely eukaryotic protein kinases (ePKs) and atypical protein kinases (aPKs); RIO kinases belong to the latter group. While there is some information about RIO kinases and their roles in animals, nothing is known about them in parasites. This is the first study to characterise a RIO1 kinase from any parasite.
Results: A full-length cDNA (Tv-rio-1) encoding a RIO1 protein kinase (Tv-RIO1) was isolated from the economically important parasitic nematode Trichostrongylus vitrinus (Order Strongylida). The uninterrupted open reading frame (ORF) of 1476 nucleotides encoded a protein of 491 amino acids, containing the characteristic RIO1 motif LVHADLSEYNTL. Tv-rio-1 was transcribed at the highest level in the third-stage larva (L3), and a higher level in adult females than in males. Comparison with homologues from other organisms showed that protein Tv-RIO1 had significant homology to related proteins from a range of metazoans and plants. Amino acid sequence identity was most pronounced in the ATP-binding motif, active site and metal binding loop. Phylogenetic analyses of selected amino acid sequence data revealed Tv-RIO1 to be most closely related to the proteins in the species of Caenorhabditis. A structural model of Tv-RIO1 was constructed and compared with the published crystal structure of RIO1 of Archaeoglobus fulgidus (Af-Rio1).
Conclusion: This study provides the first insights into the RIO1 protein kinases of nematodes, and a foundation for further investigations into the biochemical and functional roles of this molecule in biological processes in parasitic nematodes
K_L \ra \mu^\pm e^\mp \nu \overline{\nu} as background to K_L \ra \mu^\pm e^\mp
We consider the process K_L \ra \mu^\pm e^\mp \nu \overline{\nu} at next to
leading order in chiral perturbation theory. This process occurs in the
standard model at second order in the weak interaction and constitutes a
potential background in searches for new physics through the modes K_L \ra
\mu^\pm e^\mp. We find that the same cut, ~MeV, used to remove
the sequential decays K_{l3}\ra \pi_{l2} pushes the B(K_L \ra \mu^\pm e^\mp
\nu \overline{\nu}) to the level, effectively removing it as a
background.Comment: 8 pages, LaTeX, 1 figure appended as postscript file after
\end{document}. Fermilab-Pub-93/024-
Isospin Violation in Chiral Perturbation Theory and the Decays \eta \ra \pi \ell \nu and \tau \ra \eta \pi \nu
I discuss isospin breaking effects within the standard model. Chiral
perturbation theory presents the appropriate theoretical framework for such an
investigation in the low--energy range. Recent results on the electromagnetic
contributions to the masses of the pseudoscalar mesons and the
amplitudes are reported. Using the one--loop formulae for the
form factors, rather precise predictions for the decay rates of can be obtained. Finally, I present an estimate of
the \tau \ra \eta \pi \nu branching ratio derived from the dominant meson
resonance contributions to this decay.Comment: 10 pages, latex, one figure available upon reques
Chiral Lagrangians at finite density
The effective SU(2) chiral Lagrangian with external sources is given in the
presence of non-vanishing nucleon densities by calculating the in-medium
contributions of the chiral pion-nucleon Lagrangian. As a by product, a
relativistic quantum field theory for Fermi many-particle systems at zero
temperature is directly derived from relativistic quantum field theory with
functional methods.Comment: 6 Pages, 3 figures, REVTeX. Extended version. Explicit Feynman rules
are give
Single-ion versus exchange anisotropy in calculating anisotropic susceptibilities of thin ferromagnetic Heisenberg films within many-body Green's function theory
We compare transverse and parallel static susceptibilities of in-plane
uniaxial anisotropic ferromagnetic Heisenberg films calculated in the framework
of many-body Green's function theory using single-ion anisotropies with the
previously investigated case of exchange anisotropies. On the basis of the
calculated observables (easy and hard axes magnetizations and susceptibilities)
no significant differences are found, i. e. it is not possible to propose an
experiment that might decide which kind of anisotropy is acting in an actual
ferromagnetic film.Comment: 16 pages, 8 figure
Chiral Perturbation Theory for the Quenched Approximation of QCD
[This version is a minor revision of a previously submitted preprint. Only
references have been changed.] We describe a technique for constructing the
effective chiral theory for quenched QCD. The effective theory which results is
a lagrangian one, with a graded symmetry group which mixes Goldstone bosons and
fermions, and with a definite (though slightly peculiar) set of Feynman rules.
The straightforward application of these rules gives automatic cancellation of
diagrams which would arise from virtual quark loops. The techniques are used to
calculate chiral logarithms in , , , and the ratio of
to . The leading
finite-volume corrections to these quantities are also computed. Problems for
future study are described.Comment: 14 page
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