Unified formalism for higher-order non-autonomous dynamical systems

This work is devoted to giving a geometric framework for describing higher-order non-autonomous mechanical systems. The starting point is to extend the Lagrangian-Hamiltonian unified formalism of Skinner and Rusk for these kinds of systems, generalizing previous developments for higher-order autonomous mechanical systems and first-order non-autonomous mechanical systems. Then, we use this unified formulation to derive the standard Lagrangian and Hamiltonian formalisms, including the Legendre-Ostrogradsky map and the Euler-Lagrange and the Hamilton equations, both for regular and singular systems. As applications of our model, two examples of regular and singular physical systems are studied.Comment: 43 pp. We have corrected and clarified the statement of Propositions 2 and 3. A remark is added after Proposition

Hamilton-Jacobi theory in multisymplectic classical field theories

The geometric framework for the Hamilton-Jacobi theory developed in previous works is extended for multisymplectic first-order classical field theories. The Hamilton-Jacobi problem is stated for the Lagrangian and the Hamiltonian formalisms of these theories as a particular case of a more general problem, and the classical Hamilton-Jacobi equation for field theories is recovered from this geometrical setting. Particular and complete solutions to these problems are defined and characterized in several equivalent ways in both formalisms, and the equivalence between them is proved. The use of distributions in jet bundles that represent the solutions to the field equations is the fundamental tool in this formulation. Some examples are analyzed and, in particular, the Hamilton-Jacobi equation for non-autonomous mechanical systems is obtained as a special case of our results.Comment: 44 p

Unified formalism for the generalized kth-order Hamilton-Jacobi problem

The geometric formulation of the Hamilton-Jacobi theory enables us to generalize it to systems of higher-order ordinary differential equations. In this work we introduce the unified Lagrangian-Hamiltonian formalism for the geometric Hamilton-Jacobi theory on higher-order autonomous dynamical systems described by regular Lagrangian functions.Comment: 9pp. Revised version: Minor corrections done. Second part of our previous work arXiv:1309.2166. arXiv admin note: substantial text overlap with arXiv:1309.216

El acoso psicológico en el trabajo o Mobbing: patología emergente

El objetivo de este artículo es resaltar la importancia del acoso psicológico en el trabajo 'mobbing', es un problema de salud pública considerado así por las Naciones Unidas (ONU), tipificado por la Organización Internacional del Trabajo (OIT) y es un delito en nuestro Código Penal Español. La Directiva marco 89/391/CEE sobre salud y seguridad en el trabajo, pretenden proteger la salud de los trabajadores, constatando que había un 8 % de empleados de la Unión Europea que sufrían acoso laboral o mobbing, acordando trasponer a los ordenamientos internos medidas de protección de la salud laboral e integridad de los trabajadores. Analizaremos los perfiles más frecuentes tanto de la víctima de l a coso como de l acosador. Así como, las graves consecuencias del acoso o mobbing tanto a nivel psíquico, como físico y social.The aim of this paper is to highlight the importance of bullying in the workplace "mobbing" is a public health problem considered so by the United Nations (UN), typified by the International Labour Organization (OIT) and is a crime in our Spanish Penal Code. The Framework Directive 89/391/EEC on health and safety at work, intended to protect the health of workers, noting that there was an 8% of EU employees who suffered harassment or mobbing, agreeing to transpose into the domestic legal measures protection of occupational health and integrity of workers. Frequently examine the profiles of both the victim of harassment and the harasser. And the serious consequences of mobbing both psychic and physical and social

Sugar-based bicyclic monomers for aliphatic polyesters: a comparative appraisal of acetalized alditols and isosorbide

Three series of polyalkanoates (adipates, suberates and sebacates) were synthesized using as monomers three sugar-based bicyclic diols derived from D-glucose (Glux-diol and isosorbide) and D-mannose (Manx-diol). Polycondensations were conducted in the melt applying similar reaction conditions for all cases. The aim was to compare the three bicyclic diols regarding their suitability to render aliphatic polyesters with enhanced thermal and mechanical properties. The ensuing polyesters had molecular weights (Mw) in the 25,000–50,000 g mol-1 range with highest values being attained for Glux-diol. All the polyesters started to decompose above 300 °C and most of them did not display perceivable crystallinity. On the contrary, they had glass transition temperatures much higher than usually found in homologous polyesters made of alkanediols, and showed a stress– strain behavior consistent with their Tg values. Glux-diol was particularly effective in increasing the Tg and to render therefore polyesters with high elastic modulus and considerable mechanical strength.Peer ReviewedPostprint (published version

Triblock copolyesters derived from lactic acid and glucose: synthesis, nanoparticle formation and simulation

ABA triblock copolyesters were synthesized by ring-opening polymerization (ROP) of l-lactide in solution initiated by a telechelic d-glucose-based polyester macroinitiator. The macroinitiator with a number-average molecular weight about 2500 g mol-1 was synthesized by non-stoichiometric polycondensation in the melt of 2,4:3,5-di-O-methylene-d-glucitol and dimethyl succinate. Two triblock copolyesters of Mn ranging between ~6000 and ~9000 g mol-1, and differing in the length of the polylactide blocks were prepared. These copolyesters started to decompose when heated at ~220 °C and degraded slowly upon aqueous incubation under physiological conditions. They did not display any perceivable crystallinity and showed a single glass transition temperature (Tg) around 60 °C with the higher value corresponding to the larger content in glucitol units. The copolyesters were able to form nanoparticles with average diameters of ~100–130 nm and satisfactory dispersity. The effect of the block lengths on size, ¿-potential values and physical stability of the nanoparticles was evaluated. A molecular dynamics simulation study allowed modelling the two-phase structure of the nanoparticles and evidenced the preference of the glucose-based block to be peripherally located.Peer ReviewedPostprint (author's final draft

Lagrangian submanifolds and dynamics on Lie affgebroids

We introduce the notion of a symplectic Lie affgebroid and their Lagrangian submanifolds in order to describe the Lagrangian (Hamiltonian) dynamics on a Lie affgebroid in terms of this type of structures. Several examples are discussed.Comment: 50 pages. Several sections update

Paciente autista en el ámbito odontológico: autoagresiones versus maltrato infantil

El paciente autista representa un reto en el ámbito odontológico. Las características propias de este trastorno les confieren un apartado especial en el terreno del maltrato infantil. Saber hacer un diagnóstico diferencial entre lesiones autoinfringidas por el propio individuo o lesiones producidas por otra persona será el campo de batalla del odontólogo. Pero no solo el maltrato se refiere a la acción, también cobra especial relevancia la omisión o la negligencia tanto de personas como de instituciones que no velan por los derechos de estas personas.The autistic patient represents a challenge in the dental field. The characteristics of this disorder gives them a special section in the field of child abuse. Knowing differential diagnosis between self inflicted injury by the individual or injuries caused by another person will be the battlefield of the dentist. But not only abuse refers to the action, also has special relevance omission or negligence of both people and institutions that do not ensure the rights of these people

Evolución de la producción y comercio mundial de Frutas en el Mundo

El análisis del consumo de fruta en el mundo obliga a estudiar su producción y comercialización. Asia es el continente que produce de forma creciente casi el 50% de la fruta mundial, importando y exportando volúmenes similares, como consecuencia de un creciente consumo interno de fruta. América produce un 21,4% de la fruta mundial, sin embargo exporta el 25% de su producción, lo que refleja un reducido consumo interno, agravado en países pobres donde el porcentaje de exportación supera el 70% de su producción. Europa aporta el 16% de la producción mundial, exportando una cuarta parte, pero importa más de la mitad de la fruta mundial, procedente de África y América. El aumento del consumo interno, los atractivos precios de los productos importados, las importaciones de contra estación y los canales de distribución fuertemente establecidos, son causas que están provocando un nuevo orden económico mundial, que puede que cambie la tendencia actual del comercio de frutas.Esta investigación ha sido financiada por el proyecto “Plan estratégico del sector agroalimentario de la Región de Murcia”, financiado por la Consejería de Agricultura y Medio Ambiente de la Región de Murcia