The Effective Lagrangian of Three Dimensional Quantum Chromodynamics

We consider the low energy limit of three dimensional Quantum Chromodynamics with an even number of flavors. We show that Parity is not spontaneously broken, but the global (flavor) symmetry is spontaneously broken. The low energy effective lagrangian is a nonlinear sigma model on the Grassmannian. Some Chern--Simons terms are necessary in the lagrangian to realize the discrete symmetries correctly. We consider also another parametrization of the low energy sector which leads to a three dimensional analogue of the Wess--Zumino--Witten--Novikov model. Since three dimensional QCD is believed to be a model for quantum anti--ferromagnetism, our effective lagrangian can describe their long wavelength excitations (spin waves).Comment: 18 page

Three Dimensional Quantum Chromodynamics

The subject of this talk was the review of our study of three ($2+1$) dimensional Quantum Chromodynamics. In our previous works, we showed the existence of a phase where parity is unbroken and the flavor group $U(2n)$ is broken to a subgroup $U(n)\times U(n)$. We derived the low energy effective action for the theory and showed that it has solitonic excitations with Fermi statistic, to be identified with the three dimensional ``baryon''. Finally, we studied the current algebra for this effective action and we found a co-homologically non trivial generalization of Kac-Moody algebras to three dimensions.Comment: 7 pages, Plain TEX, talk presented by S.G. Rajeev at the XXVI INTERNATIONAL CONFERENCE ON HIGH ENERGY PHYSICS, DALLAS TX AUG. 199

Baryons as Solitons in Three Dimensional Quantum Chromodynamics

We show that baryons of three dimensional Quantum Chromodynamics can be understood as solitons of its effective lagrangian. In the parity preserving phase we study, these baryons are fermions for odd $N_c$ and bosons for even $N_c$, never anyons. We quantize the collective variables of the solitons and there by calculate the flavor quantum numbers, magnetic moments and mass splittings of the baryon. The flavor quantum numbers are in agreement with naive quark model for the low lying states. The magnetic moments and mass splittings are smaller in the soliton model by a factor of $\log {F_\pi\over N_c m_\pi}$. We also show that there is a dibaryon solution that is an analogue of the deuteron. These solitons can describe defects in a quantum anti--ferromagnet.Comment: 22 pages + 4 figures (figures not included, postscript files available upon request

SU(3) Family Gauge Symmetry and the Axion

We analyze the structure of a recently proposed effective field theory (EFT) for the generation of quark and lepton mass ratios and mixing angles, based on the spontaneous breaking of an SU(3) family gauge symmetry at a high scale F. We classify the Yukawa operators necessary to seed the masses, making use of the continuous global symmetries that they preserve. One global U(1), in addition to baryon number and electroweak hypercharge, remains unbroken after the inclusion of all operators required by standard-model-fermion phenomenology. An associated vacuum symmetry insures the vanishing of the first-family quark and charged-lepton masses in the absence of the family gauge interaction. If this U(1) symmetry is taken to be exact in the EFT, broken explicitly by only the QCD-induced anomaly, and if the breaking scale F is taken to lie in the range 10 to 9 - 10 to 12 GeV, then the associated Nambu-Goldstone boson is a potential QCD axion.Comment: References added and clarifications in Vacuum Structure sectio

Neutrinos and SU(3) Family Gauge Symmetry

We include the standard-model (SM) leptons in a recently proposed framework for the generation of quark mass ratios and Cabibbo-Kobayashi-Maskawa (CKM) mixing angles from an SU(3) family gauge interaction. The set of SM-singlet scalar fields describing the spontaneous breaking is the same as employed for the quark sector. The imposition at tree-level of the experimentally correct Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix, in the form of a tri-bi maximal structure, fixes several of the otherwise free parameters and renders the model predictive. The normal hierarchy among the neutrino masses emerges from this scheme.Comment: 9 pages, 3 tables; a comment added to clarify the effects of additional Yukawa operators; final version in PR

Design and analysis of a wire-driven flexible manipulator for bronchoscopic interventions

Bronchoscopic interventions are widely performed for the diagnosis and treatment of lung diseases. However, for most endobronchial devices, the lack of a bendable tip restricts their access ability to get into distal bronchi with complex bifurcations. This paper presents the design of a new wire-driven continuum manipulator to help guide these devices. The proposed manipulator is built by assembling miniaturized blocks that are featured with interlocking circular joints. It has the capability of maintaining its integrity when the lengths of actuation wires change due to the shaft flex. It allows the existence of a relatively large central cavity to pass through other instruments and enables two rotational degrees of freedom. All these features make it suitable for procedures where tubular anatomies are involved and the flexible shafts have to be considerably bent in usage, just like bronchoscopic interventions. A kinematic model is built to estimate the relationship between the translations of actuation wires and the manipulator tip position. A scale-up model is produced for evaluation experiments and the results validate the performance of the proposed mechanism

Efecto del estrés producido por la mezcla de sales en la concentración de aldehído malónico, proteínas y enzimas antioxidantes de Leymus chinensis de tres colores foliares diferentes

The mixed salt stress is common in nature. Salt stressalways affects plant growth. Different plant species have different adaptive capacity to salty soil. Leymus chinensis is an herbaceous plant with different leaf colors. However, little research was conducted to explore the different tolerance mechanisms to salt stress among the three different leaf colour genotypes of Leymus chinensis (grey green, transitional color, yellow green). Pot experiments for Leymus chinensis in three leaf colors were conducted under mixed salt treatments in 2010. Malondialdehyde (MDA) and protein concentrations, and the activity of various antioxidant enzymes [i.e., superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR)] were determined and compared among the three leaf color genotypes of Leymus chinensis. The concentrations of MDA and protein, and the activity of antioxidant enzymes showed an increasing trend with increasing pHs in almost all three leaf colors, and all of them became highest when salt stress and pH values were also highest. Moreover, antioxidant enzymes were the highest in the grey-green leaf color, and the lowest in the yellow green leaf color after exposure to the same pH treatment. The results suggested that all three leaf colors of Leymus chinensis were tolerant to salt stress, and the salt-tolerance declined according to the order of grey green > transitional color > yellow green of Leymus chinensis. This study can give us a better understanding of the intra-species adaptation to mixed salt soils.El estrés causado por mezcla de sales en el suelo es común en la naturaleza. El estrés salino siempre afecta el crecimiento de las plantas. Plantas de especies diferentes difieren en su capacidad de adaptación al estrés por sales en el suelo. Leymus chinensis es una planta herbácea con diferentes colores foliares. Sin embargo, se han conducido pocos estudios tendientes a determinar los diferentes mecanismos de tolerancia al estrés salino entre los tres genotipos de color foliar diferente de L. chinensis (grisáceo verdoso, color intermedio, amarillo verdoso). En 2010, se condujeron experimentos en macetas usando genotipos de L. chinensis de tres colores diferentes de hoja expuestos o no a tratamientos conteniendo una mezcla de sales. Las concentraciones de aldehído malónico (MDA) y proteínas, y la actividad de varias enzimas antioxidantes [es decir, la superóxido dismutasa (SOD), catalasa (CAT), ascórbico peroxidasa (APX), glutatión reductasa (GR), dehidroascórbico reductasa (DHAR) y monodehidroascórbico reductasa (MDHAR)] se determinaron y compararon entre los tres genotipos de color foliar diferente de L. chinensis. Las concentraciones de MDA y proteínas, y la actividad de enzimas antioxidantes mostraron una tendencia a incrementarse a mayores pHs en casi todos los colores foliares, y las tendencias en los tres colores foliares alcanzaron su punto máximo cuando el estrés salino y los valores de pH fueron máximos. Más aún, las concentraciones de las enzimas antioxidantes fueron las más altas en el color grisáceo verdoso, intermedias en el color intermedio, y las más bajas en el color amarillo verdoso después de la exposición al mismo tratamiento de pH. Los resultados sugirieron que los genotipos de los tres colores foliares de L. chinensis fueros tolerantes al estrés salino, y la tolerancia a la sal declinó de acuerdo al orden grisáceo verdoso > color intermedio > amarillo verdoso de L. chinensis. Este estudio puede proveer un mejor entendimiento de la adaptación intraespecífica de L. chinensis a suelos salinos.Fil: Zhou, C.. Chinese Academy of Science; China. Liaoning University; ChinaFil: Busso, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Yang, Y. G.. Liaoning University; ChinaFil: Zhang, Z.. Shenyang University; ChinaFil: Wang, Z. W.. Chinese Academy of Science; ChinaFil: Yang, Y. F.. Northeast Normal University; ChinaFil: Han, X. G.. Chinese Academy of Science; Chin

Robust filtering with randomly varying sensor delay: The finite-horizon case

Copyright [2009] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.In this paper, we consider the robust filtering problem for discrete time-varying systems with delayed sensor measurement subject to norm-bounded parameter uncertainties. The delayed sensor measurement is assumed to be a linear function of a stochastic variable that satisfies the Bernoulli random binary distribution law. An upper bound for the actual covariance of the uncertain stochastic parameter system is derived and used for estimation variance constraints. Such an upper bound is then minimized over the filter parameters for all stochastic sensor delays and admissible deterministic uncertainties. It is shown that the desired filter can be obtained in terms of solutions to two discrete Riccati difference equations of a form suitable for recursive computation in online applications. An illustrative example is presented to show the applicability of the proposed method