A BPS Skyrme model and baryons at large Nc

Within the class of field theories with the field contents of the Skyrme model, one submodel can be found which consists of the square of the baryon current and a potential term only. For this submodel, a Bogomolny bound exists and the static soliton solutions saturate this bound. Further, already on the classical level, this BPS Skyrme model reproduces some features of the liquid drop model of nuclei. Here, we investigate the model in more detail and, besides, we perform the rigid rotor quantization of the simplest Skyrmion (the nucleon). In addition, we discuss indications that the viability of the model as a low energy effective field theory for QCD is further improved in the limit of a large number of colors N_c.Comment: latex, 23 pages, 1 figure, a numerical error in section 3.2 corrected; matches published versio

Investigation of restricted baby Skyrme models

A restriction of the baby Skyrme model consisting of the quartic and potential terms only is investigated in detail for a wide range of potentials. Further, its properties are compared with those of the corresponding full baby Skyrme models. We find that topological (charge) as well as geometrical (nucleus/shell shape) features of baby skyrmions are captured already by the soliton solutions of the restricted model. Further, we find a coincidence between the compact or non-compact nature of solitons in the restricted model, on the one hand, and the existence or non-existence of multi-skyrmions in the full baby Skyrme model, on the other hand.Comment: latex, 18 pages, 2 figures; some typos correcte

Compact shell solitons in K field theories

Some models providing shell-shaped static solutions with compact support (compactons) in 3+1 and 4+1 dimensions are introduced, and the corresponding exact solutions are calculated analytically. These solutions turn out to be topological solitons, and may be classified as maps $S^3 \to S^3$ and suspended Hopf maps, respectively. The Lagrangian of these models is given by a scalar field with a non-standard kinetic term (K field) coupled to a pure Skyrme term restricted to $S^2$, rised to the appropriate power to avoid the Derrick scaling argument. Further, the existence of infinitely many exact shell solitons is explained using the generalized integrability approach. Finally, similar models allowing for non-topological compactons of the ball type in 3+1 dimensions are briefly discussed.Comment: 10 pages, latex, 2 figures, change in title and introduction. Discussion section, 2 figures and references adde

Ring-shaped exact Hopf solitons

The existence of ring-like structures in exact hopfion solutions is shown.Comment: version accepted for publication in JMP, includes symmetry transformation for finite paramete

A Theoretical Framework for Modeling Asymmetric, Nonpositive Definite and Nonuniform Distance Functions on Rn

In this paper, we give theoretical foundations for modeling distance functions on the usual Euclidean space Rn, wheredistance may refer to physical kilometers, liters of fuel consumed, time spent in traveling, or transportation cost. In ourapproach, a distance function d is derived from a function F0 called the fundamental function of d. Our distancefunctions, unlike metrics, can be asymmetric and non-positive definite, and unlike the Lp norms, they can be nonuniform.We illustrate our theoretical framework by modeling an asymmetric and non-uniform distance function on R2which can take negative values

Millimeter polarisation of the protoplanetary nebula OH 231.8+4.2: A follow-up study with CARMA

In order to investigate the characteristics and influence of the magnetic field in evolved stars, we performed a follow-up investigation of our previous submillimeter analysis of the proto-planetary nebula (PPN) OH 231.8+4.2 (Sabin et al. 2014), this time at 1.3mm with the CARMA facility in polarisation mode for the purpose of a multi-scale analysis. OH 231.8+4.2 was observed at ~2.5" resolution and we detected polarised emission above the 3-sigma threshold (with a mean polarisation fraction of 3.5 %). The polarisation map indicates an overall organised magnetic field within the nebula. The main finding in this paper is the presence of a structure mostly compatible with an ordered toroidal component that is aligned with the PPN's dark lane. We also present some alternative magnetic field configuration to explain the structure observed. These data complete our previous SMA submillimeter data for a better investigation and understanding of the magnetic field structure in OH 231.8+4.2.Comment: 7 pages, 5 figures, 2 tables. Accepted for publication in MNRA

Mineralogía de la fracción arcilla y comportamiento del hierro, aluminio y manganeso frente a diferentes extractantes de suelos con características ferrálticas de la sierra Morena de Huelva (España)

137 páginas.-- 65 figuras.-- 19 tablas.-- referencias-- 6 perfiles de suelos.-- Memoria presentada en el XIX Curso Internacional de Edafología y Biología VegetalDirector: Pérez Rodríguez, José LuisLas propiedades fisicoquímicas de los suelos vienen. determinadas por la naturaleza y proporción de los minerales presentes en la fracción arcilla. El estudio mineralógico es por lo tanto, de mucha importancia para el estudio, clasificaci6n y aprovechamiento de los suelos. La clasificación americana incluye un nivel de clasificación que es la familia, utilizando para ello el conocimiento de la mineralogía de los horizontes de los perfiles de suelos. Las familias, conjuntamente con la series del suelo, constituyen los niveles más bajos del sistema. Estas se definen sobre criterios de valor pragmático, con especial enfoque pura la utilización práctica del suelo: agricultura, geotécnica, etc. Para definir las familias se consideran los siguientes aspectos 1. Distribución por tamaño de partículas en los horizontes de menor actividad biológica 2. Mineralogía de los horizontes. 3. Régimen de temperatura del suelo. 4. Espesor del suelo penetrado por las raíces.Patrocinado por la U.N.E.S.C.O., Instituto de Cooperación Iberoamericana, Consejo Superior de Investigaciones Científicas y Universidad de SevillaPeer reviewe

Survival Rate and Morphological Growth Patterns of Five Populations of \u3cem\u3eFestuca dolichophylla\u3c/em\u3e Under Similar Conditions

The majority of the natural grasslands of Perú are located in the Puna region; they are the only source of feed for raising animals in this area, and they also protect the soil from erosion. Festuca dolichophylla is a representative species with high productivity in this ecosystem. The aim of this study was to evaluate survival rate and morphological growth patterns of five populations of Festuca dolichophylla under similar conditions. Five accessions were obtained from each population: Pastales Huando Peasant Community - Huancavelica (CCPH), Lachocc South American Camelids Research and Development Center of the National University of Huancavelica (CIDCSL), Junin, Pasco, and Puno. Six cuttings were obtained from each accession. They were planted in a block design in a uniform soil in the CCPH. After twelve months of establishment all plants were cut to five cm in height and survival rate was estimated. Plant height, number of stems, and leaf number were monitored twice a month; growth rate, stem emergence rate, and leaf emergence rate were calculated and data was analyzed for each month. Accessions from Puno had a 96.67% survival rate, which was significantly higher (p\u3c0.05) than accessions from CIDCSL (43.33% survival) but similar to accessions from the other populations. The morphological growth patterns showed differences between populations and high variability along the evaluation period; this variability and differences are likely due to the genetic constitution of each accession since the environment was similar. This information is crucial for further genetic breeding programs; however, first a morphologic and genetic characterization is necessary. We also observed an orderly growth of this species; first, the plants grow in size, then they increase their stem number, and finally the number of leaves increases. To our knowledge this is the first study that compares morphological growth patterns in different populations of Festuca dolichophylla under similar conditions

Using the generalized collage theorem for estimating unknown parameters in perturbed mixed variational equations

In this paper, we study a mixed variational problem subject to perturbations, where the noise term is modelled by means of a bilinear form that has to be understood to be “small” in some sense. Indeed, we consider a family of such problems and provide a result that guarantees existence and uniqueness of the solution. Moreover, a stability condition for the solutions yields a Generalized Collage Theorem, which extends previous results by the same authors. We introduce the corresponding Galerkin method and study its convergence. We also analyze the associated inverse problem and we show how to solve it by means of the mentioned Generalized Collage Theorem and the use of adequate Schauder bases. Numerical examples show how the method works in a practical context.Project MTM2016-80676-P (AEI/FEDER, UE)Junta de Andalucía Grant FQM35