Regularity and mass conservation for discrete coagulation-fragmentation equations with diffusion

We present a new a-priori estimate for discrete coagulation fragmentation systems with size-dependent diffusion within a bounded, regular domain confined by homogeneous Neumann boundary conditions. Following from a duality argument, this a-priori estimate provides a global L2 bound on the mass density and was previously used, for instance, in the context of reaction-diffusion equations. In this paper we demonstrate two lines of applications for such an estimate: On the one hand, it enables to simplify parts of the known existence theory and allows to show existence of solutions for generalised models involving collision-induced, quadratic fragmentation terms for which the previous existence theory seems difficult to apply. On the other hand and most prominently, it proves mass conservation (and thus the absence of gelation) for almost all the coagulation coefficients for which mass conservation is known to hold true in the space homogeneous case.

Strategic mass killings

Since World War II there have been about fifty episodes of large-scale mass killings of civilians and massive forced displacements. They were usually meticulously planned and independent of military goals. We provide a model where conflict onset, conflict intensity and the decision to commit mass killings are all endogenous, with two main goals: (1) to identify the key variables and situations that make mass killings more likely to occur; and (2) to distinguish conditions under which mass killings and military conflict intensity reinforce each other from situations where they are substitute modes of strategic violence. We predict that mass killings are most likely in societies with large natural resources, significant proportionality constraints for rent sharing, low productivity and low state capacity. Further, massacres are more likely in a civil than in an interstate war, as in the latter group sizes matter less for future rents. In non polarized societies there are asymmetric equilibria with only the larger group wanting to engage in massacres. In such settings the smaller group compensates for this by fighting harder in the first place. In this case we can talk of mass killings and fighting efforts to be substitutes. In contrast, in polarized societies either both or none of the groups can be ready to do mass killings in case of victory. Under the "shadow of mass killings" groups fight harder. Hence, in this case massacres and fighting are complements. We also present novel empirical results on the role of natural resources in mass killings and on what kinds of ethnic groups are most likely to be victimized in massacres and forced resettlements, using group level panel data.

Geolocalitzáció en temps real sobre Google Maps

L’objectiu d’aquest projecte és crear un sistema de seguiment d’una flota de vehicles amb GPS en temps real. A partir d’un mòdul de captació, el servidor recull la informació geogràfica dels vehicles i l’emmagatzema. I amb un mòdul de processament, es mostra i controla els vehicles, els punts d’interès i els polígons del sistema de Geofencing. En primer lloc, faig una introducció a l’estat de l’art dels sistemes de seguiment de vehicles. A continuació, analitzo els requeriments, especifico el comportament desitjat del sistema, explico el disseny i la implementació. Per últim, faig un seguit de proves per extreure’n les conclusions.

Spatial distribution of economic activities: an empirical approach usingself-organizing maps

The aim of this paper is to analyse the colocation patterns of industries and firms. We study the spatial distribution of firms from different industries at a microgeographic level and from this identify the main reasons for this locational behaviour. The empirical application uses data from Mercantile Registers of Spanish firms (manufacturers and services). Inter-sectorial linkages are shown using self-organizing maps. Key words: clusters, microgeographic data, self-organizing maps, firm location JEL classification: R10, R12, R34

Análisis de la dimensión ambiental de la tenencia de la tierra. El caso de la Zona Protectora y Parque Nacional Volcán Tenorio de Costa Rica

El presente estudio consiste en la elaboración de un mapa del estado de tenencia de la tierra actual de la Zona Protectora y Parque Nacional Volcán Tenorio situado al norte de Costa Rica. A partir de este resultado cartográfico se efectuarán estudios referentes al estado legal de las propiedades, al tipo de propiedad, a la ubicación de las propiedades dentro del Área Silvestre Protegida y al evalúo de los conflictos legales dentro de ésta. Por otro lado, se analiza la cobertura de la tierra y el estado de conservación. La metodología utilizada se basa en el uso de Sistemas de Información Geográfica y en la verificación de la información mediante puntos GPS tomados al campo y su análisis en la oficina. Los resultados muestran una reubicación de los planos más precisa y real que la indicada por el Catastro Nacional. Aunque las propiedades privadas son mayoritarias, el área de estudio presenta en general un porcentaje alto de masa boscosa, mientras que en las zonas limítrofes se encuentra una fragmentación del hábitat determinada por herbazales. Este estudio contribuye a una mejor gestión y conservación del Área Protegida y es un avance en el ordenamiento territorial del país.

Gestión en el territorio de una empresa de seguridad mediante estándares GIS e integración de datos con Google Maps.

Estudi teòric sobre els Sistemes d'Informació Geogràfica (GIS) i sobre les especificacions que està publicant el Open Geospatial Consortium (OGC) com estàndards oberts que permetin les comunicacions entre distints GIS.

Gestión en el territorio de una empresa de seguridad mediante estándares SIG e integración de datos con GOOGLE MAPS

Amb l'evolució de les noves tecnologies, els Sistemes d'Informació Geogràfica (SIG) es basen cada vegada menys en plataformes propietàries (únicament a l'abast de grans companyies). L'objectiu que persegueix el Open Geospatial Consortium (OGC) és que tot el món pugui beneficiar-se de la informació geogràfica, fent que els serveis estiguin disponibles en qualsevol xarxa, aplicació o sistema.

Desenvolupament d'edició geogràfica segons l'estàndard WFS-T sobre l'API de Google Maps

El present treball tractarà d'aprofitar Google Maps i les eines lliures disponibles, per construir unes llibreries Javascript d'ús obert que permetin afegir serveis de persistència als serveis de cartografia ja disponibles.

Representació dels jaciments arqueològics del Museu de Molins de Rei amb Google Maps

En aquest document es recull i descriuen els treballs fets al Treball de Final de Carrera, en la especialitat de Sistemes d'Informació Geogràfica (SIG). La finalitat del projecte es utilitzar les tecnologies SIG per crear una pagina web on es representin els jaciments arqueològics del Museu de Molins de Rei de forma visual fàcil e interactiva sobre el mateix mapa. Per això es farà una web que sigui un "Mash-Up" utilitzant les les funcionalitats que proporcionen les Api de Google Maps.

Representació dels Jaciments de Molins de Rei amb Google Maps

El Museu Municipal de Molins de Rei desitja posar a la disposició dels visitants, tant presencials com virtuals, el seu fons, així com disposar d'una eina que permeti visualitzar sobre un mapa la distribució dels seus jaciments.L'usuari d'aquest projecte disposarà d'una eina que li facilitarà triar els jaciments en funció del període històric que vol consultar, accedint a través d'aquests a la documentació relativa als períodes històrics del jaciment, la de les troballes corresponents a cada període històric del jaciment i a les imatges tant del jaciment com dels objectes que s'hi han trobat.També disposarà d'una eina que li donarà les indicacions adequades per tal de poder arribar des de l'adreça que desitgi fins a la seu del museu o fins als diferents jaciments.

Using self organizing maps on compositional data

Self-organizing maps (Kohonen 1997) is a type of artificial neural network developedto explore patterns in high-dimensional multivariate data. The conventional versionof the algorithm involves the use of Euclidean metric in the process of adaptation ofthe model vectors, thus rendering in theory a whole methodology incompatible withnon-Euclidean geometries.In this contribution we explore the two main aspects of the problem:1. Whether the conventional approach using Euclidean metric can shed valid resultswith compositional data.2. If a modification of the conventional approach replacing vectorial sum and scalarmultiplication by the canonical operators in the simplex (i.e. perturbation andpowering) can converge to an adequate solution.Preliminary tests showed that both methodologies can be used on compositional data.However, the modified version of the algorithm performs poorer than the conventionalversion, in particular, when the data is pathological. Moreover, the conventional ap-proach converges faster to a solution, when data is \well-behaved".Key words: Self Organizing Map; Artificial Neural networks; Compositional data

Weighted Logratio Biplots, Correspondence Analysis and Spectral Maps

Starting with logratio biplots for compositional data, which are based on the principle of subcompositional coherence, and then adding weights, as in correspondence analysis, we rediscover Lewi's spectral map and many connections to analyses of two-way tables of non-negative data. Thanks to the weighting, the method also achieves the property of distributional equivalence

Compositional evolution with mass transfer in closed systems

Evolution of compositions in time, space, temperature or other covariates is frequentin practice. For instance, the radioactive decomposition of a sample changes its composition with time. Some of the involved isotopes decompose into other isotopes of thesample, thus producing a transfer of mass from some components to other ones, butpreserving the total mass present in the system. This evolution is traditionally modelledas a system of ordinary di erential equations of the mass of each component. However,this kind of evolution can be decomposed into a compositional change, expressed interms of simplicial derivatives, and a mass evolution (constant in this example). A rst result is that the simplicial system of di erential equations is non-linear, despiteof some subcompositions behaving linearly.The goal is to study the characteristics of such simplicial systems of di erential equa-tions such as linearity and stability. This is performed extracting the compositional differential equations from the mass equations. Then, simplicial derivatives are expressedin coordinates of the simplex, thus reducing the problem to the standard theory ofsystems of di erential equations, including stability. The characterisation of stabilityof these non-linear systems relays on the linearisation of the system of di erential equations at the stationary point, if any. The eigenvelues of the linearised matrix and theassociated behaviour of the orbits are the main tools. For a three component system,these orbits can be plotted both in coordinates of the simplex or in a ternary diagram.A characterisation of processes with transfer of mass in closed systems in terms of stability is thus concluded. Two examples are presented for illustration, one of them is aradioactive decay

Holomorphic maps between moduli spaces

We prove that every non-constant holomorphic map&em&M&/em&&sub&g,p&/sub&→ &em&M&/em&&sub& g',p'&/sub& between moduli spaces of Riemann surfaces is a forgetful map, provided that g ≥ 6 and g' ≤ 2g-2.

The implementation of liquid chromatography tandem mass spectrometry for the official control of lipophilic toxins in seafood: Single-laboratory validation under four chromatographic conditions

We performed a comprehensive study to assess the fit for purpose of four chromatographic conditions for the determination of six groups of marine lipophilic toxins (okadaic acid and dinophysistoxins, pectenotoxins, azaspiracids, yessotoxins, gymnodimine and spirolides) by LC-MS/MS to select the most suitable conditions as stated by the European Union Reference Laboratory for Marine Biotoxins (EURLMB). For every case, the elution gradient has been optimized to achieve a total run-time cycle of 12 min. We performed a single-laboratory validation for the analysis of three relevant matrices for the seafood aquaculture industry (mussels, pacific oysters and clams), and for sea urchins for which no data about lipophilic toxins have been reported before. Moreover, we have compared the method performance under alkaline conditions using two quantification strategies: the external standard calibration (EXS) and the matrix-matched standard calibration (MMS). Alkaline conditions were the only scenario that allowed detection windows with polarity switching in a 3200 QTrap mass spectrometer, thus the analysis of all toxins can be accomplished in a single run, increasing sample throughput. The limits of quantification under alkaline conditions met the validation requirements established by the EURLMB for all toxins and matrices, while the remaining conditions failed in some cases. The accuracy of the method and the matrix effects where generally dependent on the mobile phases and the seafood species. The MMS had a moderate positive impact on method accuracy for crude extracts, but it showed poor trueness for seafood species other than mussels when analyzing hydrolyzed extracts. Alkaline conditions with EXS and recovery correction for OA were selected as the most proper conditions in the context of our laboratory. This comparative study can help other laboratories to choose the best conditions for the implementation of LC-MS/MS according to their own necessities.