178 research outputs found
The SO(N) principal chiral field on a half-line
We investigate the integrability of the SO(N) principal chiral model on a
half-line, and find that mixed Dirichlet/Neumann boundary conditions (as well
as pure Dirichlet or Neumann) lead to infinitely many conserved charges
classically in involution. We use an anomaly-counting method to show that at
least one non-trivial example survives quantization, compare our results with
the proposed reflection matrices, and, based on these, make some preliminary
remarks about expected boundary bound-states.Comment: 7 pages, Late
Wheat lines, suffering structural rearrangements between wheat-1BS and rye-1RS chromosomes, display differential patterns of magnesium accumulation
Poster no. 238Two near isogenic lines, designated as 1RS and 1RW, resulting from the recombination of the rye (Secale cereale) chromosome 1RS with chromosome 1BS of bread wheat (Triticum aestivum), differ in a relatively small region of that short chromosome arm. We have recently reported that chromosome rearrangements in this region imply modifications in the dosage of some genes (including OPRIII codifying an enzyme involved in jasmonic acid (JA) biosynthesis pathway). This dosage difference confer differential drought resistance in a way primarily associated to the capacity of roots for soil exploration. An emerging question is whether or not those rearrangements also differentially influence plant mineral nutrition. In the present study we analyzed the ionome of 1RS and 1RW, which unveiled the existence of relevant differences in the distribution of magnesium (Mg) between the shoot and the root of these lines. Following this observation, we explored the physiological and molecular determinants of differential magnesium accumulation observed.Instituto de Recursos BiolĂłgicosFil: Gualano, L.D. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto TecnolĂłgico ChascomĂșs; Argentina. Universidad Nacional de San MartĂn; ArgentinaFil: Moriconi, Jorge. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto TecnolĂłgico ChascomĂșs; Argentina. Universidad Nacional de San MartĂn; ArgentinaFil: Tranquilli, Gabriela. Instituto Nacional de TecnologĂa Agropecuaria (INTA). Instituto de Recursos BiolĂłgicos; ArgentinaFil: Santa-MarĂa, Guillermo E. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto TecnolĂłgico ChascomĂșs; Argentina. Universidad Nacional de San MartĂn; Argentin
Physiological and genetic characterization of wheat lines sharply differing in sodium accumulation
Poster no. 129Improving nutrient use efficiency is an important objective in modern breeding programs. Our group attempts to elucidate the components that contribute to greater efficiencies of potassium (K) acquisition and utilization in wheat (Triticum aestivum), and its nexus with sodium (Na) dynamics.Instituto de Recursos BiolĂłgicosFil: Silva, Martha M. Instituto Nacional de TecnologĂa Agropecuaria (INTA). Instituto de Recursos BiolĂłgicos; ArgentinaFil: Moriconi, Jorge. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto TecnolĂłgico ChascomĂșs; Argentina. Universidad Nacional de San MartĂn; ArgentinaFil: Gualano, L.D. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto TecnolĂłgico ChascomĂșs; Argentina. Universidad Nacional de San MartĂn; ArgentinaFil: Tranquilli, Gabriela. Instituto Nacional de TecnologĂa Agropecuaria (INTA). Instituto de Recursos BiolĂłgicos; ArgentinaFil: Santa-MarĂa, Guillermo E. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto TecnolĂłgico ChascomĂșs; Argentina. Universidad Nacional de San MartĂn; Argentin
Noncommutative Integrable Field Theories in 2d
We study the noncommutative generalization of (euclidean) integrable models
in two-dimensions, specifically the sine- and sinh-Gordon and the U(N)
principal chiral models. By looking at tree-level amplitudes for the
sinh-Gordon model we show that its na\"\i ve noncommutative generalization is
{\em not} integrable. On the other hand, the addition of extra constraints,
obtained through the generalization of the zero-curvature method, renders the
model integrable. We construct explicit non-local non-trivial conserved charges
for the U(N) principal chiral model using the Brezin-Itzykson-Zinn-Justin-Zuber
method.Comment: 18 pages, 1 figure; v2: references adde
Vortex Reconnection as the Dissipative Scattering of Dipoles
We propose a phenomenological model of vortex tube reconnection at high
Reynolds numbers. The basic picture is that squeezed vortex lines, formed by
stretching in the region of closest approach between filaments, interact like
dipoles (monopole-antimonopole pairs) of a confining electrostatic theory. The
probability of dipole creation is found from a canonical ensemble spanned by
foldings of the vortex tubes, with temperature parameter estimated from the
typical energy variation taking place in the reconnection process. Vortex line
reshuffling by viscous diffusion is described in terms of directional
transitions of the dipoles. The model is used to fit with reasonable accuracy
experimental data established long ago on the symmetric collision of vortex
rings. We also study along similar lines the asymmetric case, related to the
reconnection of non-parallel vortex tubes.Comment: 8 pages, 3 postscript figure
A wheat/rye polymorphism affects seminal root length and yield across different irrigation regimes
The introgression of a small segment of wheat (Triticumaestivum L.) chromosome arm 1BS in the distal region of rye (Secalecereale L.) 1RS.1BL arm translocation in wheat (henceforth 1RSRW) was previously associated with reduced grain yield, carbon isotope discrimination and stomatal conductance, suggesting reduced access to soil moisture. Here we show that lines with the normal 1RS arm have longer roots than lines with the 1RSRW arm in both field and hydroponic experiments. In the 1RSRW lines, differences in seminal root length were associated with a developmentally regulated arrest of the root apical meristem (RAM). Approximately 10 days after germination, the seminal roots of the 1RSRW plants showed a gradual reduction in elongation rate, and stopped growing a week later. Seventeen days after germination, the roots of the 1RSRW plants showed altered gradients of reactive oxygen species and emergence of lateral roots close to the RAM, suggesting changes in the root meristem. The 1RSRW lines also showed reduced biomass (estimated by Normalized Differences Vegetation Index) and grain yield relative to the 1RS lines, with larger differences under reduced or excessive irrigation than under normal irrigation. These results suggest that this genetic variation could be useful to modulate root architecture.Fil: Howell, Tyson. University of California; Estados UnidosFil: Moriconi, Jorge Ignacio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs). Universidad Nacional de San MartĂn. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs); ArgentinaFil: Zhao, Xueqiang. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Joshua Hegarty. University of California; Estados UnidosFil: Fahima, Tzion. University of Haifa; IsraelFil: Santa Maria, Guillermo Esteban. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs). Universidad Nacional de San MartĂn. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs); Argentin
The boundary supersymmetric sine-Gordon model revisited
We argue that, contrary to previous claims, the supersymmetric sine-Gordon
model with boundary has a two-parameter family of boundary interactions which
preserves both integrability and supersymmetry. We also propose the
corresponding boundary S matrix for the first supermultiplet of breathers.Comment: 9 pages, LaTeX; amssymb, no figures; v2: one equation and one
reference added; v3: more references and a "note added
Circulation Statistics in Three-Dimensional Turbulent Flows
We study the large limit of the loop-dependent characteristic
functional , related
to the probability density function (PDF) of the circulation around a closed
contour . The analysis is carried out in the framework of the
Martin-Siggia-Rose field theory formulation of the turbulence problem, by means
of the saddle-point technique. Axisymmetric instantons, labelled by the
component of the strain field -- a partially annealed variable in
our formalism -- are obtained for a circular loop in the plane, with
radius defined in the inertial range. Fluctuations of the velocity field around
the saddle-point solutions are relevant, leading to the lorentzian asymptotic
behavior . The
subleading correction and the asymmetry between right and left PDF tails due to
parity breaking mechanisms are also investigated.Comment: Computations are discussed in a more detailed way; accepted for
publication in Physical Review
Two-year observations of the Jupiter polar regions by JIRAM on board Juno
We observed the evolution of Jupiter's polar cyclonic structures over two years between February 2017 and February 2019, using polar observations by the Jovian InfraRed Auroral Mapper, JIRAM, on the Juno mission. Images and spectra were collected by the instrument in the 5âÎŒm wavelength range. The images were used to monitor the development of the cyclonic and anticyclonic structures at latitudes higher than 80° both in the northern and the southern hemispheres. Spectroscopic measurements were then used to monitor the abundances of the minor atmospheric constituents water vapor, ammonia, phosphine and germane in the polar regions, where the atmospheric optical depth is less than 1. Finally, we performed a comparative analysis with oceanic cyclones on Earth in an attempt to explain the spectral characteristics of the cyclonic structures we observe in Jupiter's polar atmosphere
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