Symplectic Regularization of Binary Collisions in the Circular N+2 Sitnikov Problem

We present a brief overview of the regularizing transformations of the Kepler problem and we relate the Euler transformation with the symplectic structure of the phase space of the N-body problem. We show that any particular solution of the N-body problem where two bodies have rectilinear dynamics can be regularized by a linear symplectic transformation and the inclusion of the Euler transformation into the group of symplectic local diffeomorphisms over the phase space. As an application we regularize a particular configuration of the circular N+2 Sitnikov problem.Comment: 23 pages, 5 figures. References to algorithmic regularization included, changes in References and small typographic corrections. Accepted in J. of Phys. A: Math. Theor 44 (2011) 265204 http://stacks.iop.org/1751-8121/44/26520

On spiking neural P systems

This work deals with several aspects concerning the formal verification of SN P systems and the computing power of some variants. A methodology based on the information given by the transition diagram associated with an SN P system is presented. The analysis of the diagram cycles codifies invariants formulae which enable us to establish the soundness and completeness of the system with respect to the problem it tries to resolve. We also study the universality of asynchronous and sequential SN P systems and the capability these models have to generate certain classes of languages. Further, by making a slight modification to the standard SN P systems, we introduce a new variant of SN P systems with a special I/O mode, called SN P modules, and study their computing power. It is demonstrated that, as string language acceptors and transducers, SN P modules can simulate several types of computing devices such as finite automata, a-finite transducers, and systolic trellis automata.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía TIC-58

Caracterización de la calidad del aire en la ciudad de Valencia: Un análisis basado en la interpolación espacial de contaminantes

Puesto que el aire es un recurso vital y que su degradación puede ocasionar daños a la salud y al medioambiente, evaluar la contaminación atmosférica de las ciudades se ha convertido en una prioridad según la Organización Mundial de la Salud (OMS). El objetivo de este trabajo ha sido determinar la calidad del aire en la ciudad de Valencia, estimando los patrones espaciales de dióxido de nitrógeno (NO2) y de partículas en suspensión (PM10) y determinando qué zonas de la ciudad superan los límites legales nacionales e internacionales. Para ello se han realizado tratamientos de interpolación y visualización mediante el programa ArcGIS. Este trabajo representa un primer paso en la necesaria producción de más investigaciones sobre justicia ambiental en Europa, particularmente en España

Energy levels of periodic solutions of the circular 2+2 Sitnikov problem

We study a 2+2 body problem introduced in a previous paper as the circular double Sitnikov problem. Since the secondary bodies are moving on the same perpendicular line where evolve the primaries, almost every solution is a collision orbit. We extend the solutions beyond collisions with a symplectic regularization and study the set of energy surfaces that contain periodic orbits and their foliations .Comment: 20 pages, 5 figures. This is not the final version

New Record of Bacopa egensis (Plantaginaceae) for the Flora of Mexico

Bacopa egensis is newly reported for the flora of Mexico and an updated key is provided for the Mexican Bacopa specie

Simulating Apoptosis Using Discrete Methods: a Membrane System and a Stochastic Approach

Membrane Systems provide an intriguing method for modeling biological systems at a molecular level. The hierarchical structure of Membrane Systems lends itself readily to mimic the nature and behavior of cells.We have refined a technique for modeling the type I and type II FAS-induced apoptosis signalling cascade. Improve- ments over our previous modeling work on apoptosis include increased efficiency for storing and sorting waiting times of reactions, a nondeterministic approach for han- dling reactions competing over limited reactants and improvements, and refinements of the model reactions. The modular nature of our systems provides flexibility with respect to future discover- ies on the signal cascade. We provide a breakdown of our algorithms and explanations on improvements we have implemented. We also give an exhaustive comparison to an established ordinary differential equations technique. Based on the results of our sim- ulations, we conclude that Membrane Systems are a useful simulation tool in Systems Biology that could provide new insight into the subcellular processes, and provide also the argument that Membrane Systems may outperform ordinary differential equation simulations when simulating cascades of reactions (as they are observed in cells

Simulating FAS-induced apoptosis by using P systems

In contrast to differential equations, P systems are an unconven- tional model of computation which takes into consideration the discrete character of the quantity of components and the inherent randomness that exists in biological phenomena. The key feature of P systems is their compartmentalised structure which represents the heterogeneity of the structural organisation of the cells, and where one can take into account the role played by membranes in the functioning of the system, for example signalling at the cell surface [13], selective uptake of sub- stances from the media [14], diffusion across different compartments [15], etc. We show here that P systems can be a reliable tool for Systems Biology and could even outperform in some cases the current simu- lation techniques based on differential equations. We will also use a strategy based on the well known Gillespie algorithm [4] but running on more than one compartment called Multi-compartmental Gillespie Algorithm [13]

La mitosis celular: una sorprendente frontera de la eficiencia

En este trabajo se presenta una frontera entre la eficiencia e ineficiencia de problemas abstractos en un marco computacional inspirado en la estructura y funcionamiento de las c´elulas de los organismos vivos. M´as concretamente, se justifica que una regla de reescritura, abstracci´on de la mitosis celular, proporciona un l´ımite de la tratabilidad de problemas, bajo el supuesto de que se verifique la conjetura P 6= NP. Como consecuencia relevante se obtienen nuevas herramientas que permiten atacar la resoluci´on de la citada conjetura en un marco absolutamente novedoso.Ministerio de Ciencia e Innovación TIN2009–13192Junta de Andalucía P08–TIC-0420

Anti-Ro52/TRIM21 antibodies are associated with aberrant inflammatory circuits in patients with systemic autoimmune rheumatic diseases

INTRODUCTION: Anti-Ro52/TRIM21 antibodies are markers for several systemic autoimmune rheumatic diseases (SARD). OBJECTIVE: To assess whether anti-Ro52/TRIM21 antibodies are related to abnormalities in inflammatory circuits. METHODS: Cross-sectional study of consecutive outpatients with SARD. Anti-Ro52/TRIM21 antibodies and serum amyloid A protein were measured by ELISA; panels for 18 cytokines and nine chemokines were analyzed on a Luminex reading platform, while high-sensitivity C-reactive protein (hs-CRP) and complement were measured by nephelometry. RESULTS: Among 167 included patients, 143 had systemic lupus erythematosus (SLE), 16 had primary Sjögren's syndrome and eight had systemic sclerosis; 41 (24%) were positive for anti-Ro52/TRIM21 antibodies. Patients with anti-Ro52/TRIM21 antibodies had higher serum levels of IL-2, IL-4, IL-6, GM-CSF, IL-21, IL-22, hs-CRP and chemokines CCL4, CXCL8, CXCL10 and CXCL12, but lower levels of complement C4. Anti-Ro52/TRIM21 antibody titers were positively correlated with IL-2, IL-4, IL-6, IL-10, IL-21, IL-22, CXCL10, and hs-CRP, and negatively with complements C3 and C4. When only SLE patients were included, no association was identified between anti-Ro52/TRIM21 antibodies and disease activity or organ-specific involvement. CONCLUSIONS: Anti-Ro52/TRIM21 antibodies are associated with aberrant cytokine circuits and elevated levels of angiogenic molecules and neutrophil and monocyte chemoattractants, which suggests an active role for these antibodies in SARD.</p

Analysis of Andean blackberry (Rubus glaucus) production models obtained by means of artificial neural networks exploiting information collected by small-scale growers in Colombia and publicly available meteorological data

The Andean blackberry (Rubus glaucus) is an important source of income in hillside regions of Colombia. However, growers have little reliable information on the factors that affect the development and yield of the crop, and therefore there is a dearth of information onhowto effectively manage the crop. Site specific information recorded by small-scale producers of the Andean blackberry on their production systems and soils coupled with publicly available meteorological data was used to develop models of such production systems. Multilayer perceptrons and Self-Organizing Maps were used as computational models in the identification and visualization of the most important variables for modeling the production of Andean blackberry. Artificial neural networks were trained with information from 20 sites in Colombia where the Andean blackberry is cultivated. Multilayer perceptrons predicted with a reasonable degree of accuracy the production response of the crop. The soil depth, the average temperature, external drainage, and the accumulated precipitation of the first month before harvest were critical determinants of productivity. A proxy variable of location was used to describe overall differences in management between farmers groups. The use of this proxy indicated that, even under essentially similar environmental conditions, large differences in production could be assigned to management effects. The information obtained can be used to determine sites that are suitable for Andean blackberry production, and to transfer ofmanagement practices from sites of high productivity to sites with similar environmental conditions which currently have lower levels of productivity