Search

We show that the recent construction of Nf = 1 baryons on the η′ domain wall can be understood as vortexes of the principal effective theory — the Chern-Simons-Higgs theory — on a 2+1-dimensional sheet. This theory has a series of vortex solutions, and the vortex with unit topological charge naturally spins Nc/2, which coincides with the spin of the one-flavor baryon in QCD. Since the Nc scaling of the vortexes is the same as that of baryons, the latter can be regarded as the former. By virtue of the particle-vortex symmetry, the dual Zhang-Hansson-Kivelson theory indicates that the quark carries topological charge 1/Nc and obeys fractional statistics. The generalization to arbitrary Nf is also discussed. [ABSTRACT FROM AUTHOR]

The roles of the lightest vector mesons ρ and ω in the multi-Skyrmion states are studied using the hidden local symmetry approach up to the next-to-leading order, including the homogeneous Wess-Zumino terms. The low-energy constants in the effective field theory are determined using the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action. With only two inputs, mρ and fπ, it is possible to determine all low-energy constants without ambiguity. The vector meson effects can be investigated by sequentially integrating vector mesons, and their geometry can be elucidated by comparing the results using the low-energy constants estimated from the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action. We found that the ρ meson reduces the masses of the multi-Skyrmion states and increases the overlaps of their constituents, whereas the ω meson repulses the constituents of the multi-Skyrmion states and increases their masses. Therefore, these vector mesons are crucial in the Skyrme model approach to nuclei. We also found that the warping factor, an essential element in the holographic model of QCD, affects the properties of the multi-Skyrmion states and cannot be ignored. [ABSTRACT FROM AUTHOR]

Picea mongolica is an endemic but endangered species in China. The spruce forest is only found in sandy forest-steppe ecotones. In this study, we examined the initial response of the quantity and refilling process of fine roots in an artificial canopy gap with a diameter of 36 m in a P. mongolica forest. Under the canopy, the fine root length densities of trees, shrubs and herbs were 2,622,864 and 3,086 m·m−2, respectively. The fine root biomass of trees, shrubs and herbs were 148, 62 and 65 g·m−2, respectively. In the gap, the fine root length density of trees was 151 m·m−2. The mean fine root densities of shrubs and herbs in the gap were 756 and 2,568 m·m−2. The fine root biomass of trees, shrubs and herbs were 9, 52 and 47 g·m−2, respectively. Two growing seasons after the gap creation, hardly any fine tree roots were found in the middle of the gap. The living tree roots in the gap edge zone were mainly located within a 4.5 m distance from the standing trees. Indices developed to show the influence of trees on fine root length density clearly revealed the effect of the vicinity of living trees on fine root length density. The root densities of shrubs and herbs did not show a clear response to gap creation despite the increase of their foliage. Our results suggest that in P. mongolica forests a gap disturbance creates a distinct tree root gap and that the gap edge trees do not extend their root systems rapidly into the formed root gap. [ABSTRACT FROM AUTHOR]

In sandy forest with a forest canopy gap for a period of over 30 years, the spruce( Picea mongolica) seedlings were monitored on two 5-m-wide transects from the center of a large gap into the surrounding forest. The farther they were to the far center, the taller grew the seedling and the more is the number of seedling. There were many seedlings under the canopy but almost all seedlings died before they grow up. Along the forest edge, growth of seedlings was temporarily enhanced by lateral penetration of light from the gap. The implications for natural forest regeneration dynamics are discussed. Our results prove that in P. mongolica forest a gap disturbance creates a non-uniform environment for regeneration of the species, and determines that the forest was a non-even aged forest. [ABSTRACT FROM AUTHOR]