Estudi exploratori per a la reconstrucció de temperatures de l'aigua i de l'aire en la conca central del llac Baikal (Sibèria) en els últims 40000 anys

Aquest estudi consisteix en un anàlisi exploratori que té per objectiu principal la realització d’una reconstrucció de la temperatura de l’aigua i l’aire del llac Baikal durant els últims 40.000 anys. El treball s’ha dut a terme mitjançant l’ús de les proxys de reconstrucció de la temperatura y la utilització dels mètodes TEX86, MAAT, i la d’aportació de matèria orgànica d’origen terrestre, el BIT, aplicant-les a la mostra VER93-2 st GC-24, extreta pel Baikal Drilling Project a la conca central, amb l’objectiu de fer una aportació de dades paleoclimàtiques per tal d’aconseguir una millora en les interpretacions de futurs esdeveniments climàtics, i d’identificar esdeveniments climàtics sobtats, tals com els Heinrich events i els Youngers Dryas. Abans de la realització de l’anàlisi de les mostres s’ha dut a terme una extrapolació de l’edat en el testimoni, degut a que l’edat del core BDP VER93-2.st.GC-24 havia estat extrapolada fins a 277,5 cm de profunditat i en el present estudi s’ha ampliat l’anàlisi fins als 460 cm. de profunditat. Un cop obtinguts els resultats s’ha realitzat un càlcul de precisió i reproductibilitat per tal de conèixer una estimació quantitativa de la variabilitat de les dades obtingudes en les diferents proxys, en el qual ha estat demostrat una baixa variabilitat de les dades, exceptuant la variabilitat del TEX86 i la precisió del MAAT. Per a la localització dels diferents esdeveniments climàtics donats durant l’Holocè i el Plistocè s’han realitzat anàlisis gràfics dels propis resultats, juntament i en comparació dels resultats realitzats per Escala et al. (r.n.p [resultats no publicats]) en la conca sud, i de l’estudi publicat per Prokopenko et al., en el que s’analitza la presència de diatomees i matèria orgànica l’Atlàntic Nord. Els resultats integrats d’Escala et al.,(r.n.p) i els d’aquest estudi coincideixen en la datació dels diferents esdeveniments, amb alguna variació hipotèticament produïda per l’extrapolació d’edat realitzada en el present estudi i la gran aportació de matèria orgànica en el lloc d’extracció del testimoni per part del riu Selenga. Aquests resultats mostren una possible relació entre els esdeveniments climàtics i la variació de la temperatura de l’aigua.

Quantitative analysis of image factors in a cultural heritage tourist destination

The tourism consumer’s purchase decision process is, to a great extent, conditioned by the image the tourist has of the different destinations that make up his or her choice set. In a highly competitive international tourist market, those responsible for destinations’ promotion and development policies seek differentiation strategies so that they may position the destinations in the most suitable market segments for their product in order to improve their attractiveness to visitors and increase or consolidate the economic benefits that tourism activity generates in their territory. To this end, the main objective we set ourselves in this paper is the empirical analysis of the factors that determine the image formation of Tarragona city as a cultural heritage destination. Without a doubt, UNESCO’s declaration of Tarragona’s artistic and monumental legacies as World Heritage site in the year 2000 meant important international recognition of the quality of the cultural and patrimonial elements offered by the city to the visitors who choose it as a tourist destination. It also represents a strategic opportunity to boost the city’s promotion of tourism and its consolidation as a unique destination given its cultural and patrimonial characteristics. Our work is based on the use of structured and unstructured techniques to identify the factors that determine Tarragona’s tourist destination image and that have a decisive influence on visitors’ process of choice of destination. In addition to being able to ascertain Tarragona’s global tourist image, we consider that the heterogeneity of its visitors requires a more detailed study that enables us to segment visitor typology. We consider that the information provided by these results may prove of great interest to those responsible for local tourism policy, both when designing products and when promoting the destination.

Escriptura de la tesi doctoral, benestar i context d'aprenentatge: Un estudi des de les percepcions dels doctorands

Les representacions que els estudiants es fan sobre les tasques acadèmiques són cabdals per entendre com les desenvolupen. Creiem que això no és una excepció en estudiants de doctorat amb les seves tesis i és per això que en aquesta recerca estem interessats en investigar com els estudiants entenen els estudis de doctorat. La literatura revisada preocupada per l’experiència del doctorat, és a dir, com els doctorands perceben aquest procés, se centra en variables de benestar, context d’aprenentatge i escriptura. Amb el propòsit d’obtenir un quadre complert sobre com els doctorands entenen fer una tesi, 627 doctorands han completat El Qüestionari de l’Experiència Doctoral (Lonka i altres, 2007) que hem procedit a adaptar a la població espanyola. Aquest instrument mesura les tres variables esmentades (al llarg de 49 enunciats de resposta Likert) i de forma general algunes qüestions del procés doctoral (8 preguntes de resposta oberta) que complementen/donen llum a la interpretació de les dades quantitatives. A més, es demana informació del context del doctorand (18 preguntes) que ajuda a entendre millor el desenvolupament de la tesi en cada cas. Donat que algunes dificultats que els estudiants manifesten en el doctorat tenen a veure amb la percepció de no disposar d’estratègies suficients per regular el procés d’escriptura, ens hem plantejat recollir dades més específiques en relació a l’escriptura de la tesi entrevistant 10 doctorands per separat i posteriorment junts en un focus grup. Pensem que la nostra investigació pot contribuir en la reflexió de la qualitat dels programes de doctorat ja que creiem que els estudiants tenen molt a dir i que cal escoltar les seves veus. A més, si els tutors disposen d’informació sobre com els seus alumnes viuen els estudis de doctorat, segurament entendran millor com porten a terme les seves tesis i podran oferir-los ajudes més ajustades.

Interpretation of wind components as compositional variables

The classical statistical study of the wind speed in the atmospheric surface layer is madegenerally from the analysis of the three habitual components that perform the wind data,that is, the component W-E, the component S-N and the vertical component,considering these components independent.When the goal of the study of these data is the Aeolian energy, so is when wind isstudied from an energetic point of view and the squares of wind components can beconsidered as compositional variables. To do so, each component has to be divided bythe module of the corresponding vector.In this work the theoretical analysis of the components of the wind as compositionaldata is presented and also the conclusions that can be obtained from the point of view ofthe practical applications as well as those that can be derived from the application ofthis technique in different conditions of weather

Study and implementation of some quantitative trading models

Quantitative or algorithmic trading is the automatization of investments decisions obeying a fixed or dynamic sets of rules to determine trading orders. It has increasingly made its way up to 70% of the trading volume of one of the biggest financial markets such as the New York Stock Exchange (NYSE). However, there is not a signi cant amount of academic literature devoted to it due to the private nature of investment banks and hedge funds. This projects aims to review the literature and discuss the models available in a subject that publications are scarce and infrequently. We review the basic and fundamental mathematical concepts needed for modeling financial markets such as: stochastic processes, stochastic integration and basic models for prices and spreads dynamics necessary for building quantitative strategies. We also contrast these models with real market data with minutely sampling frequency from the Dow Jones Industrial Average (DJIA). Quantitative strategies try to exploit two types of behavior: trend following or mean reversion. The former is grouped in the so-called technical models and the later in the so-called pairs trading. Technical models have been discarded by financial theoreticians but we show that they can be properly cast into a well defined scientific predictor if the signal generated by them pass the test of being a Markov time. That is, we can tell if the signal has occurred or not by examining the information up to the current time; or more technically, if the event is F_t-measurable. On the other hand the concept of pairs trading or market neutral strategy is fairly simple. However it can be cast in a variety of mathematical models ranging from a method based on a simple euclidean distance, in a co-integration framework or involving stochastic differential equations such as the well-known Ornstein-Uhlenbeck mean reversal ODE and its variations. A model for forecasting any economic or financial magnitude could be properly defined with scientific rigor but it could also lack of any economical value and be considered useless from a practical point of view. This is why this project could not be complete without a backtesting of the mentioned strategies. Conducting a useful and realistic backtesting is by no means a trivial exercise since the \laws" that govern financial markets are constantly evolving in time. This is the reason because we make emphasis in the calibration process of the strategies' parameters to adapt the given market conditions. We find out that the parameters from technical models are more volatile than their counterpart form market neutral strategies and calibration must be done in a high-frequency sampling manner to constantly track the currently market situation. As a whole, the goal of this project is to provide an overview of a quantitative approach to investment reviewing basic strategies and illustrating them by means of a back-testing with real financial market data. The sources of the data used in this project are Bloomberg for intraday time series and Yahoo! for daily prices. All numeric computations and graphics used and shown in this project were implemented in MATLAB^R scratch from scratch as a part of this thesis. No other mathematical or statistical software was used.

The European Union in North Korea: Current Realities and Paths for Future Engagement – A Qualitative and Quantitative Study

Malgrat la rellevància estratègica i el paper desestabilitzador de Corea del Nord a la regió econòmicament més dinàmica del món, la UE no compta amb cap estratègia clara per involucrar-se amb aquest país. Combinant tècniques d’anàlisi qualitatives i quantitatives, aquest treball pretén descobrir possibles contradiccions internes que impedeixin la definició d'una política exterior europea coherent i efectiva amb respecte a Corea del Nord, així com discrepàncies entre les percepcions d’actors interns de la UE i les d’actors externs. S'han detectat importants diferències d’expectatives i mancances en termes de coherència, tant entre les visions expressades pels actors interns com entre les opinions d’aquests actors i les dels futurs líders sudcoreans enquestats – diferències que fins i tot afecten la promoció dels drets humans

Arqueología de la producción agrícola. Aplicación de técnicas de análisis estadístico y geocomputacional a un caso de estudio del IV-II milenio ANE en la Cuenca del Río Grande (Perú)

Muchas investigaciones arqueobotánicas, desde un enfoque cualitativo-descriptivo, limitan el propio campo de estudio a los análisis de presencia/ausencia y/o de frecuencia de taxones a partir de su recuento en los conjuntos vegetales. De esa manera, los datos proporcionados resultan ser inconcluyentes y no fiables para la reconstrucción del paleoambiente, la determinación de la dieta alimenticia y de la práctica económica realizada (recolección VS agricultura), y totalmente insuficientes para determinar los cambios históricos ocurridos en los procesos productivos. Por lo que concierne el Perú, desde los primeros estudios con referencia a restos vegetales recuperados en yacimientos arqueológicos, principalmente de la costa, se documenta el importante papel que han desarrollado las especies vegetales en la vida de las comunidades pre-hispánicas. No obstante la excepcional abundancia y óptima preservación de este tipo de material (botánico) en muchos de los yacimientos arqueológicos de esta región, gracias a las extremas condiciones climáticas y ambientales sobre todo de sus áridas zonas costeras, los estudios arqueobotánicos desarrollados hasta el momento son muy escasos y las limitaciones análiticas que presentan en su mayoría reflejan la poca importancia dada a las investigaciones arqueobotánicas. En el presente trabajo desarrollamos y aplicamos una metodología analítica de tipo cuantitativa para el estudio de los macrorestos vegetales procedentes de un yacimiento de la Costa sur del Perú. Con ello pretendemos obtener datos representativos y objetivos de los conjuntos analizados, cuyo procesado lleve a una exhaustiva y correcta interpretación de la información.

Modelling the cardiovascular system for automatic interpretation of the blood pressure curve

A four compartment model of the cardiovascular system is developed. To allow for easy interpretation and to minimise the number of parameters, an effort was made to keep the model as simple as possible. A sensitivity analysis is first carried out to determine which are the most important model parameters to characterise the blood pressure signal. A four stage process is then described which accurately determines all parameter values. This process is applied to data from three patients and good agreement is shown in all cases.

Slow recoveries: A structural interpretation

An analysis of the performance of GDP, employment and otherlabor market variables following the troughs in postwar U.S. businesscycles points to much slower recoveries in the three most recentepisodes, but does not reveal any significant change over time in therelation between GDP and employment. This leads us to characterizethe last three episodes as slow recoveries, as opposed to jobless recoveries.We use the estimated New Keynesian model in Galí-Smets-Wouters (2011) to provide a structural interpretation for the slowerrecoveries since the early nineties.

Fuzzy coding in constrained ordinations

Canonical correspondence analysis and redundancy analysis are two methods of constrained ordination regularly used in the analysis of ecological data when several response variables (for example, species abundances) are related linearly to several explanatory variables (for example, environmental variables, spatial positions of samples). In this report I demonstrate the advantages of the fuzzy coding of explanatory variables: first, nonlinear relationships can be diagnosed; second, more variance in the responses can be explained; and third, in the presence of categorical explanatory variables (for example, years, regions) the interpretation of the resulting triplot ordination is unified because all explanatory variables are measured at a categorical level.

Unfolding a symmetric matrix

Graphical displays which show inter--sample distances are importantfor the interpretation and presentation of multivariate data. Except whenthe displays are two--dimensional, however, they are often difficult tovisualize as a whole. A device, based on multidimensional unfolding, isdescribed for presenting some intrinsically high--dimensional displays infewer, usually two, dimensions. This goal is achieved by representing eachsample by a pair of points, say $R_i$ and $r_i$, so that a theoreticaldistance between the $i$-th and $j$-th samples is represented twice, onceby the distance between $R_i$ and $r_j$ and once by the distance between$R_j$ and $r_i$. Self--distances between $R_i$ and $r_i$ need not be zero.The mathematical conditions for unfolding to exhibit symmetry are established.Algorithms for finding approximate fits, not constrained to be symmetric,are discussed and some examples are given.

Contribution biplots

In order to interpret the biplot it is necessary to know which points usually variables are the ones that are important contributors to the solution, and this information is available separately as part of the biplot s numerical results. We propose a new scaling of the display, called the contribution biplot, which incorporates this diagnostic directly into the graphical display, showing visually the important contributors and thus facilitating the biplot interpretation and often simplifying the graphical representation considerably. The contribution biplot can be applied to a wide variety of analyses such as correspondence analysis, principal component analysis, log-ratio analysis and the graphical results of a discriminant analysis/MANOVA, in fact to any method based on the singular-value decomposition. In the contribution biplot one set of points, usually the rows of the data matrix, optimally represent the spatial positions of the cases or sample units, according to some distance measure that usually incorporates some form of standardization unless all data are comparable in scale. The other set of points, usually the columns, is represented by vectors that are related to their contributions to the low-dimensional solution. A fringe benefit is that usually only one common scale for row and column points is needed on the principal axes, thus avoiding the problem of enlarging or contracting the scale of one set of points to make the biplot legible. Furthermore, this version of the biplot also solves the problem in correspondence analysis of low-frequency categories that are located on the periphery of the map, giving the false impression that they are important, when they are in fact contributing minimally to the solution.

The biased balance: Observation, formalism and interpretation of a dissymmetric measuring device

This paper studies a balance whose unobservable fulcrum is not necessarilylocated at the middle of its two pans. It presents three differentmodels, showing how this lack of symmetry modifies the observation, theformalism and the interpretation of such a biased measuring device. Itargues that the biased balance can be an interesting source of inspirationfor broadening the representational theory of measurement.

Biased quantitative measurement of interval ordered homothetic preferences

We represent interval ordered homothetic preferences with a quantitative homothetic utility function and a multiplicative bias. When preferences are weakly ordered (i.e. when indifference is transitive), such a bias equals 1. When indifference is intransitive, the biasing factor is a positive function smaller than 1 and measures a threshold of indifference. We show that the bias is constant if and only if preferences are semiordered, and we identify conditions ensuring a linear utility function. We illustrate our approach with indifference sets on a two dimensional commodity space.