Coisotropic regularization of singular Lagrangians

We present an alternative approach to the usual treatments of singular Lagrangians. It is based on a Hamiltonian regularization scheme inspired on the coisotropic embedding of presymplectic systems. A Lagrangian regularization of a singular Lagrangian is a regular Lagrangian defined on an extended velocity phase space that reproduces the original theory when restricted to the initial configuration space. A Lagrangian regularization does not always exists, but a family of singular Lagrangians is studied for which such a regularization can be described explicitly. These regularizations turn out to be essentially unique and provide an alternative setting to quantize the corresponding physical systems. These ideas can be applied both in classical mechanics and field theories. Several examples are discussed in detail. 1995 American Institute of Physics.

Local model predictive control experiences with differential driven wheeled mobile robots

This work extends a previously developed research concerning about the use of local model predictive control in differential driven mobile robots. Hence, experimental results are presented as a way to improve the methodology by considering aspects as trajectory accuracy and time performance. In this sense, the cost function and the prediction horizon are important aspects to be considered. The aim of the present work is to test the control method by measuring trajectory tracking accuracy and time performance. Moreover, strategies for the integration with perception system and path planning are briefly introduced. In this sense, monocular image data can be used to plan safety trajectories by using goal attraction potential fields

Mobile Robot Local Predictive Control under Perception Constraints

This research extends a previously developed work concerning about the use of local model predictive control in mobile robots. Hence, experimental results are presented as a way to improve the methodology by considering aspects as trajectory accuracy and time performance. In this sense, the cost function and the prediction horizon are important aspects to be considered. The platformused is a differential driven robot with a free rotating wheel. The aim of the present work is to test the control method by measuring trajectory tracking accuracy and time performance. Moreover, strategies for the integration with perception system and path planning are also introduced. In this sense, monocular image data provide an occupancy grid where safety trajectories are computed by using goal attraction potential fields

Migration Determinants at a Local Level

This paper is about determinants of migration at a local level. We use data from Catalan municipalities in order to understand what explains migration patterns trying to identify whether they are main explained by amenities or economic characteristics. We distinguish three typologies of migration in terms of distance travelled: short-distance, short-medium-distance and medium-distance and we hypothesize whether migration determinants vary across these groups. Our results show that, effectively, there are some noticeable differences, suggest that spatial issues must be taken into account and provide some insights for future research. Keywords: population dynamics, spatial econometrics. JEL codes: C21, R0, R23

Hamiltonian formalism for nonlocal Lagrangians

A Hamiltonian formalism is set up for nonlocal Lagrangian systems. The method is based on obtaining an equivalent singular first order Lagrangian, which is processed according to the standard Legendre transformation and then, the resulting Hamiltonian formalism is pulled back onto the phase space defined by the corresponding constraints. Finally, the standard results for local Lagrangians of any order are obtained as a particular case.

Lvpercal: Nota a livio 1, 5, 1

In Livius 1,5,1 the reading Lupercal hoc ludicrum has been interpreted with the meaning of Lupercal game or festivity; however, this interpretation goes against the use in Latin of the singular form Lupercal, wich is used to refer to the cavern and not to the games, wich are always referred to with theplural form Lupercalia. Lexical reasons suggest that Lupercal should also be interpreted here in its usual local sense.

Déficit en la provisión local de servicios públicos y tipologia municipal

Este trabajo analiza el déficit en la provisión de servicios públicos locales en España, especialmente en su relación con el tamaño de los municipios y con el número de núcleos de población que forman cada municipio, una variable largamente olvidada. El análisis empírico muestra que ambas variables son relevantes. Los resultados se revelan de interés en las discusiones relativas a la consolidación municipal como instrumento para eliminar el déficit de provisión de servicios

Comunicación institucional y prensa local de Manlleu en el franquismo, 1940-1957

[spa] El artículo trata de la retórica del periodismo y la comunicación institucional en la localidad de Manlleu (Barcelona, Spain). El boletín municipal Manlleu (1940-1957) fue una cabecera local en el franquismo de posguerra que publicó los programas de fiesta mayor. El estudio muestra cómo creó la propaganda política una memoria histórica con el martirologio y los agravios de la República. Esta investigación forma parte de los estudios sobre fiesta y discurso Celebratio et oratio. Y contribuye a los repertorios históricos de comunicación local e institucional (ReCoLI). El repertorio combina los ámbitos del discurso, las instituciones locales y la ideología, bajo una perspectiva histórica. "Institutional communication and local press during the Franco regime in Manlleu (Spain, 1940-1957)".

Vanishing Clams on an iberian beach: local consequences and global implication of accelerating loss of shells to tourism

Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978-1981 and 2008-2010) in one small embayment on the Mediterranean coast of Spain. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. Concomitantly, abundance of mollusk shells along the shoreline decreased almost three-fold (2.62) and displayed a tight inverse correlation with tourist arrivals. A four-fold increase in tourist arrivals observed globally over the last 30 years has likely induced a comparable worldwide acceleration in shell removal from marine shorelines and exerted multiple negative (but currently unquantifiable) habitat changes that may include increased beach erosion, changes in carbon and calcium cycles, and decline in diversity and abundance of organisms dependent on shell availability.

Efectes de les separacions o divorcis en el rendiment acadèmic dels alumnes de 5è i 6è d’una escola local

Aquest Treball Final de Grau aporta els resultats d’un estudi sobre els efectes i condicionats que suposa pel rendiment acadèmic dels alumnes de cicle superior de primària el divorci o la separació dels seus progenitors. Ens trobem davant l’augment del nombre de trencaments familiars, que ha esdevingut un fenomen clarament observable en la societat, es tracta d’un fenomen complex, en el qual entren en joc nombroses variables. I el trencament també suposa conseqüències socials, en primer lloc, pels fills/es. En una primera part ens endinsem en les aportacions i teories que han defensat diversos experts al llarg del temps sobre aquest fet. En una segona part es presenten les conclusions i els acords extrets de diverses entrevistes amb mestres d’una escola local en relació a la possible vinculació entre trencament familiar i rendiment acadèmic. I, per últim, s’acaben comparat les visions dels autors teòrics amb les aportacions i visions dels educadors professionals; per arribar a les principals conclusions que, no es pot generalitzar els efectes negatius de la ruptura, cal veure també les possibilitats positives del moment i, per últim, destacar que la manera amb la qual la família s'afronta a la ruptura té una importància crucial a l'hora de determinar l'impacte d'aquesta la ruptura en els fills.

The burden of hospital malnutrition in Spain: methods and development of the PREDyCES® study

It is well known that hospital malnutrition is a highly prevalent condition associated to increase morbidity and mortality as well as related healthcare costs. Although previous studies have already measured the prevalence and/or costs of hospital nutrition in our country, their local focus (at regional or even hospital level) make that the true prevalence and economic impact of hospital malnutrition for the National Health System remain unknown in Spain. The PREDyCES® (Prevalence of hospital malnutrition and associated costs in Spain) study was aimed to assess the prevalence of hospital malnutrition in Spain and to estimate related costs. Some aspects made this study unique: a) It was the first study in a representative sample of hospitals of Spain; b) different measures to assess hospital malnutrition (NRS2002, MNA as well as anthropometric and biochemical markers) where used both at admission and discharge and, c) the economic consequences of malnutrition where estimated using the perspective of the Spanish National Health System.

Generation of symmetric periodic orbits by a heteroclinic loop formed by two singular points and their invariant manifolds of dimension 1 and 2 in R3

In this paper we will find a continuous of periodic orbits passing near infinity for a class of polynomial vector fields in R3. We consider polynomial vector fields that are invariant under a symmetry with respect to a plane and that possess a “generalized heteroclinic loop” formed by two singular points e+ and e− at infinity and their invariant manifolds � and . � is an invariant manifold of dimension 1 formed by an orbit going from e− to e+, � is contained in R3 and is transversal to . is an invariant manifold of dimension 2 at infinity. In fact, is the 2–dimensional sphere at infinity in the Poincar´e compactification minus the singular points e+ and e−. The main tool for proving the existence of such periodic orbits is the construction of a Poincar´e map along the generalized heteroclinic loop together with the symmetry with respect to .

Symmetric periodic orbits near a heteroclinic loop in R3 formed by two singular points, a semistable periodic orbit and their invariant manifolds

In this paper we consider C1 vector fields X in R3 having a “generalized heteroclinic loop” L which is topologically homeomorphic to the union of a 2–dimensional sphere S2 and a diameter connecting the north with the south pole. The north pole is an attractor on S2 and a repeller on . The equator of the sphere is a periodic orbit unstable in the north hemisphere and stable in the south one. The full space is topologically homeomorphic to the closed ball having as boundary the sphere S2. We also assume that the flow of X is invariant under a topological straight line symmetry on the equator plane of the ball. For each n ∈ N, by means of a convenient Poincar´e map, we prove the existence of infinitely many symmetric periodic orbits of X near L that gives n turns around L in a period. We also exhibit a class of polynomial vector fields of degree 4 in R3 satisfying this dynamics.

Symmetric periodic orbits near a heteroclinic loop formed by two singular points and their invariant manifolds of dimension 1 and 2

In this paper we consider vector fields in R3 that are invariant under a suitable symmetry and that posses a “generalized heteroclinic loop” L formed by two singular points (e+ and e −) and their invariant manifolds: one of dimension 2 (a sphere minus the points e+ and e −) and one of dimension 1 (the open diameter of the sphere having endpoints e+ and e −). In particular, we analyze the dynamics of the vector field near the heteroclinic loop L by means of a convenient Poincar´e map, and we prove the existence of infinitely many symmetric periodic orbits near L. We also study two families of vector fields satisfying this dynamics. The first one is a class of quadratic polynomial vector fields in R3, and the second one is the charged rhomboidal four body problem.

El desarrollo local en la ciudad media europea ante los proyectos de T.A.V.

La ciudad media o intermedia europea ha sido calificada de «OGNI» (Objeto Geográfico No Identificado) por la falta de teorizaciones propias. Esta afirmación es especialmente cierta en el campo del desarrollo local, en las particularidades que juegan en el proceso de aprovechamiento de los recursos locales para crear un desarrollo endógeno. Esta investigación pretende, en primer lugar, recoger las opiniones de varios autores e instituciones para definir las características cuantitativas y cualitativas de esta realidad urbana. En segundo lugar, se quiere contextualizar la ciudad media en el territorio europeo y en las políticas a esta escala. Finalmente, se describen tres ejemplos de desarrollo local en ciudades medias a partir de la implantación del Tren de Alta Velocidad para mostrar cuáles son los factores diferenciales del desarrollo local en este fenómeno urbano