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701.
The \(\eta \,\rightarrow \,3\pi \) decays are a valuable source of information on low energy QCD. Yet they were not used for an extraction of the three flavor chiral symmetry breaking order parameters until now. We use a Bayesian approach in the framework of resummed chiral perturbation theory to obtain constraints on the quark condensate and pseudoscalar decay constant in the chiral limit. We compare our results with recent CHPT and lattice QCD fits and find some tension, as the \(\eta \,\rightarrow \,3\pi \) data seem to prefer a larger ratio of the chiral order parameters. The results also disfavor a very large value of the pseudoscalar decay constant in the chiral limit, which was found by some recent work. In addition, we present results of a combined analysis including \(\eta \,\rightarrow \,3\pi \) decays and \(\pi \pi \) scattering and though the picture does not changed appreciably, we find some tension between the data we use. We also try to extract information on the mass difference of the light quarks, but the uncertainties prove to be large. 相似文献
702.
Adriana Araújo de Almeida-Apolonio Fabiana Gomes da Silva Dantas Allan Belarmino Rodrigues Claudia Andréa Lima Cardoso Melyssa Negri Kelly Mari Pires de Oliveira 《Natural product research》2019,33(16):2363-2367
Cryptococcosis is an opportunistic disease with a worldwide distribution. This disease is caused by fungi of the genus Cryptococcus, and its treatment is limited to several antifungals. In this study, the antifungal, cytotoxic and mutagenic properties of ethanol extracts from the bark and leaves of Annona coriacea were evaluated against the standard Cryptococcus species and clinical yeast specimens. Both extracts of A. coriacea showed inhibitory activity of 1.5 mg/mL for all of the yeasts tested. The number of viable cells at the lowest tested concentration was 0.187 mg/mL. The extracts that were tested showed inhibitory activity and reduced the fungal growth of the Cryptococcus gattii species and Cryptococcus neoformans species complexes, suggesting that this plant may be an effective alternative treatment for cryptococcosis. 相似文献
703.
Sasaki M Takaishi S Miyasaka H Sugiura K Yamashita M 《Journal of the American Chemical Society》2005,127(43):14958-14959
Scanning tunneling microscopy (STM) has been measured in quasi-one-dimensional (Quasi-ID) bromo-bridged Ni(III) complexes. In the STM image of [Ni(pn)2Br]Br2 (pn = (R)-1,2-diaminopropane), the bright spots are fluctuated zigzags. Such a result indicates that the methyl groups of the pn ligands are not arranged on the right- and left-hand alternatively along the chains, but in the domain structures or fluctuated structures. This is the first direct observation of the disorder of the methyl group of pn ligands in real space. 相似文献
704.
We demonstrate the equivalence of all loop closed topological string amplitudes on toric local Calabi-Yau threefolds with computations of certain knot invariants for Chern-Simons theory. We use this equivalence to compute the topological string amplitudes in certain cases to very high degree and to all genera. In particular we explicitly compute the topological string amplitudes for 2 up to degree 12 and 1× 1 up to total degree 10 to all genera. This also leads to certain novel large N dualities in the context of ordinary superstrings, involving duals of type II superstrings on local Calabi-Yau three-folds without any fluxes.This research is supported in part by NSF grants PHY-9802709 and DMS-0074329 相似文献
705.
706.
Dumitrescu A Rudzevich VL Romanenko VD Mari A Schoeller WW Bourissou D Bertrand G 《Inorganic chemistry》2004,43(21):6546-6548
Persistent phosphinyl radicals featuring the 2,6-bis(trifluoromethyl)phenyl group were prepared and characterized. Their electronic structure was theoretically investigated, and their low-temperature dimerization into the corresponding diphosphines was found to be strongly inhibited when the sterically very demanding (tert-butyl)(trimethylsilyl)amino substituent was used. 相似文献
707.
An automorphism α of a group G is called a noetherian automorphism if for each ascending chain
of subgroups of G there is a positive integer m such that
for all n ≥ m. The structure of the group of all noetherian automorphisms of a group is investigated in this paper. 相似文献
708.
We model the evolution of the Internet at the autonomous system level as a process of competition for users and adaptation of bandwidth capability. From a weighted network formalism, where both nodes and links are weighted, we find the exponent of the degree distribution as a simple function of the growth rates of the number of autonomous systems and connections in the Internet, both empirically measurable quantities. Our approach also accounts for a high level of clustering as well as degree-degree correlations, both with the same hierarchical structure present in the real Internet. Further, it also highlights the interplay between bandwidth, connectivity, and traffic of the network. 相似文献
709.
LetV be a Banach space whose dualV * is Va?ák, that is, weakly countably determined. Then an equivalent locally uniformly rotund norm onV is constructed. According to a recent example of Mercourakis, this is a real extension of an earlier result of Godefroy Troyanski, Whitfield and Zizler, whereV * has been a subspace of a weakly compactly generated Banach space. 相似文献
710.
Bernardi A Arosio D Manzoni L Monti D Posteri H Potenza D Mari S Jiménez-Barbero J 《Organic & biomolecular chemistry》2003,1(5):785-792
Two new cholera toxin (CT) ligands (4 and 5) are described. The new ligands were designed starting from the known GM1 mimics 2 and 3 by replacement of their GalNAc residue with the C4 isomer GlcNAc. As predicted by molecular modelling, the conformational properties of the equivalent pairs 2-4 and 3-5 are very similar and their affinity for CT is of the same order of magnitude. NMR experiments have also proved that 5 occupies the GM1-binding site of the toxin and have revealed its bound conformation. 相似文献