Climate change in the Atlantic Ocean since the 1940's and the effects on the global climate

En aquest projecte s’ha estudiat la relació entre els canvis en les temperatures superficials de l’Oceà Atlàntic i els canvis en la circulació atmosfèrica en el segle XX. Concretament s’han analitzat dos períodes de estudi: el primer des del 1940 al 1960 i el segon des del 1980 fins al 2000. S’ha posat especial interès en les anomalies en les temperatures superficials del mar en la regió tropical de l’Oceà Atlàntic i la possible interconnexió amb els canvis climàtics observats i predits. Per a la realització de l’estudi s’han dut a terme una sèrie d’experiments utilitzant el model climàtic elaborat a la universitat d’UCLA (UCLA‐AGCM model). Els resultats obtinguts han estat analitzats en forma de mapes i figures per a cada variable d’estudi. També s’ha fet una comparació entre els resultats obtinguts i altres trobats en altres treballs publicats sobre el mateix tema de recerca. Els resultats obtinguts són molt amplis i poden tenir diverses interpretacions. Tot i així algunes de les conclusions a les quals s’ha arribat són: les diferències més significatives per a les variables estudiades i trobades a partir dels resultats obtinguts del model per als dos períodes d’estudi són en els mesos d’hivern i a la zona dels tròpics; concretament a parts del nord de sud Amèrica i a parts del nord d’Àfrica. S’han trobat també canvis significatius en els patrons de precipitació sobre aquestes mateixes zones. També s’ha observant un moviment cap al nord de la zona d’interconvergència tropical i pot ser degut a l’anòmal gradient trobat a la zona equatorial en les temperatures superficial de l’Oceà. Tot i així per a una definitiva discussió i conclusions sobre els resultats dels experiments, seria necessari un estudi més ampli i profund.

Estimating patterns of leaf herbivory along an altitudinal transect in NE Queensland rainforests: might global warming increase leaf herbivory in tropical rainforests?

Climate change has been taking place at unprecedented rates over the past decades. These fast alterations caused by human activities are leading to a global warming of the planet. Warmer temperatures are going to have important effects on vegetation and especially on tropical forests. Insects as well will be affected by climate change. This study tested the hypothesis that higher temperatures lead to a higher insect pressure on vegetation. Visual estimations of leaf damage were recorded and used to assess the extent of herbivory in nine 0.1ha plots along an altitudinal gradient, and therefore a temperature gradient. These estimations were made at both a community level and a species level, on 2 target species. Leaf toughness tests were performed on samples from the target species from each plot. Results showed a strong evidence of increasing insect damage along increasing temperature, with no significant effect from the leaf toughness.

Soporte geoespacial para modelos de distribución de especies (I): generalización del mapa de vegetación del Montseny apoyada en información de imágenes de satélite

Los mapas de vegetación son a menudo utilizados como proxis de una estratificación de hábitats para generar distribuciones geográficas contínuas de organismos a partir de datos discretos mediante modelos multi-variantes. Sin embargo, los mapas de vegetación suelen ser poco apropiados para ser directamente aplicados a este fin, pues sus categorías no se concibieron con la intención de corresponder a tipos de hábitat. En este artículo presentamos y aplicamos el método de Agrupamiento por Doble Criterio para generalizar un mapa de vegetación extraordinariamente detallado (350 clases) del Parque Natural del Montseny (Cataluña) en categorías que mantienen la coherencia tanto desde el punto de vista estructural (a través de una matriz de disimilaridad espectral calculada mediante una imágen del satélite SPOT-5) como en términos de vegetación (gracias a una matriz de disimilaridad calculada mediante propiedades de vegetación deducidas de la leyenda jerárquica del mapa). El método simplifica de 114 a 18 clases el 67% del área de estudio. Añadiendo otras agregaciones más triviales basadas exclusivamente en criterios de cubierta de suelo, el 73% del área de estudio pasa de 167 a 25 categorías. Como valor añadido, el método identifica el 10% de los polígonos originales como anómalos (a partir de comparar las propiedades espectrales de cada polígono con el resto de los de su clases), lo que implica cambios en la cubierta entre las fechas del soporte utilizado para generar el mapa original y la imagen de satélite, o errores en la producción de éste.

The Evolution of the Climate Change Regime: Beyond a North-South Divide?

This research primarily analyses relevant climate bargaining dynamics that have been informed by a North-South impasse. This working paper argues that the first stage of negotiations for a climate convention indeed witnessed a North-South divide which became institutionalized in the Framework Convention on Climate Change. However, in subsequent negotiation rounds the key loci of bargaining struggles was centered between developed countries, in which relevant North-South cooperation dynamics were also present. Finally, this paper assesses the unfinished post-Kyoto bargaining process in which two trends are already being observed: both the emergence of a new geopolitics between the United States and major developing countries, and a fragmentation process within the South, in which the Copenhagen Accord itself has begun to institutionalize such fragmentation.

How does monetary policy change? evidence on inflation targeting countries

We examine the evolution of monetary policy rules in a group of inflation targeting countries (Australia, Canada, New Zealand, Sweden and the United Kingdom) applying moment- based estimator at time-varying parameter model with endogenous regressors. Using this novel flexible framework, our main findings are threefold. First, monetary policy rules change gradually pointing to the importance of applying time-varying estimation framework. Second, the interest rate smoothing parameter is much lower that what previous time-invariant estimates of policy rules typically report. External factors matter for all countries, albeit the importance of exchange rate diminishes after the adoption of inflation targeting. Third, the response of interest rates on inflation is particularly strong during the periods, when central bankers want to break the record of high inflation such as in the U.K. or in Australia at the beginning of 1980s. Contrary to common wisdom, the response becomes less aggressive after the adoption of inflation targeting suggesting the positive effect of this regime on anchoring inflation expectations. This result is supported by our finding that inflation persistence as well as policy neutral rate typically decreased after the adoption of inflation targeting.

Parents, television and cultural change

This paper develops a model of cultural transmission where television plays a central role for socialization. Parents split their free time between educating their children which is costly and watching TV which though entertaining might socialize the children to the wrong trait. The free to air television industry maximizes advertisement revenue. We show that TV watching is increasing in cultural coverage, cost of education, TV's entertainment value and decreasing in the perceived cultural distance between the two traits. A monopolistic television industry captures all TV watching by both groups if the perceived cultural distance between groups is small relative to the TV's entertainment value. Otherwise, more coverage will be given to the most profitable group where profitability increases in group size, advertisement sensitivity and perceived cultural distance. This leads to two possible steady states where one group is larger but both groups survive in the long run. Competition in the media industry might lead to cultural extinction but only if one group is very insensitive to advertisement and not radical enough not to watch TV. We briefly discuss the existing evidence for the empirical predictions of the model.

Contact melting of a three-dimensional phase change material on a flat substrate

In this paper a model is developed to describe the three dimensional contact melting process of a cuboid on a heated surface. The mathematical description involves two heat equations (one in the solid and one in the melt), the Navier-Stokes equations for the flow in the melt, a Stefan condition at the phase change interface and a force balance between the weight of the solid and the countering pressure in the melt. In the solid an optimised heat balance integral method is used to approximate the temperature. In the liquid the small aspect ratio allows the Navier-Stokes and heat equations to be simplified considerably so that the liquid pressure may be determined using an igenfunction expansion and finally the problem is reduced to solving three first order ordinary differential equations. Results are presented showing the evolution of the melting process. Further reductions to the system are made to provide simple guidelines concerning the process. Comparison of the solutions with experimental data on the melting of n-octadecane shows excellent agreement.

Noves tecnologies per l'estudi de l'arqueologia de Patagònia (Amèrica del Sud)

The goal of this project was the historical study of Patagonia, the southernmost human settled area of the world. Our aim has been the anlysis of those societies to understand how they maintained their socioeconomic system, that is to say, how social reproduction allowed resolving the basic contradiction between production and reproduction, which is characteristic of all hunter-gatherer societies. New computational technologies have allowed a bettwer integration of the big amount and diversity of data needed. We have analyzed the historical evolution of inter-group and intra-group social relationships among nomad patagonian societies. We have compared different social answers in front of the radical change of their immediate reality produced by european colonization. We have exhaustively analyzed the results of archaeological excavations from diferent regions. We have also integrated information from anthropology, ethnohistory and geography. We are developing computing programs to integrate geographical actual data with paleoenvironmental data about the dynamic nature of soil formation, vegetation, hidrography, etc., with information about the history of productive action and how products were distributed among different human groups.

OER in Portugal as agent of curriculum innovation and technological change. Inducing practices of "new" teaching standards

This research project aimed the following goal: promote the creation, use and disclosure of OER in a Group of Schools, involving schools and teachers from different learning levels, expecting to test and validate the use of OER, in a learning-teaching model towards curricular innovation. Defining as a starting point different subjects and teachers from distinct academic areas, we have implemented a set of activities leading to the creation of OER supported, when possible, in FLOSS tools. We adopted an action research methodology with a dual purpose: to act within a community of teachers and students, while increasing at the same time their knowledge, as well as the researcher's. The activity was developed cooperatively in order to process a certain reality of the teaching-learning process, through practical/reflective action towards it and inducing its implementation by others in the Portuguese School System, based on the production and sharing OER.

Compositional hypotheses of subcompositional stability and specific perturbation change and their testing

In standard multivariate statistical analysis common hypotheses of interest concern changes in mean vectors and subvectors. In compositional data analysis it is now well established that compositional change is most readily described in terms of the simplicial operation of perturbation and that subcompositions replace the marginal concept of subvectors. To motivate the statistical developments of this paper we present two challenging compositional problems from food production processes.Against this background the relevance of perturbations and subcompositions can beclearly seen. Moreover we can identify a number of hypotheses of interest involvingthe specification of particular perturbations or differences between perturbations and also hypotheses of subcompositional stability. We identify the two problems as being the counterpart of the analysis of paired comparison or split plot experiments and of separate sample comparative experiments in the jargon of standard multivariate analysis. We then develop appropriate estimation and testing procedures for a complete lattice of relevant compositional hypotheses

Alternative ways to estimate change points in multinomial sequences. An application to an authorship attribution problem

The statistical analysis of literary style is the part of stylometry that compares measurable characteristicsin a text that are rarely controlled by the author, with those in other texts. When thegoal is to settle authorship questions, these characteristics should relate to the author’s style andnot to the genre, epoch or editor, and they should be such that their variation between authors islarger than the variation within comparable texts from the same author.For an overview of the literature on stylometry and some of the techniques involved, see for exampleMosteller and Wallace (1964, 82), Herdan (1964), Morton (1978), Holmes (1985), Oakes (1998) orLebart, Salem and Berry (1998).Tirant lo Blanc, a chivalry book, is the main work in catalan literature and it was hailed to be“the best book of its kind in the world” by Cervantes in Don Quixote. Considered by writterslike Vargas Llosa or Damaso Alonso to be the first modern novel in Europe, it has been translatedseveral times into Spanish, Italian and French, with modern English translations by Rosenthal(1996) and La Fontaine (1993). The main body of this book was written between 1460 and 1465,but it was not printed until 1490.There is an intense and long lasting debate around its authorship sprouting from its first edition,where its introduction states that the whole book is the work of Martorell (1413?-1468), while atthe end it is stated that the last one fourth of the book is by Galba (?-1490), after the death ofMartorell. Some of the authors that support the theory of single authorship are Riquer (1990),Chiner (1993) and Badia (1993), while some of those supporting the double authorship are Riquer(1947), Coromines (1956) and Ferrando (1995). For an overview of this debate, see Riquer (1990).Neither of the two candidate authors left any text comparable to the one under study, and thereforediscriminant analysis can not be used to help classify chapters by author. By using sample textsencompassing about ten percent of the book, and looking at word length and at the use of 44conjunctions, prepositions and articles, Ginebra and Cabos (1998) detect heterogeneities that mightindicate the existence of two authors. By analyzing the diversity of the vocabulary, Riba andGinebra (2000) estimates that stylistic boundary to be near chapter 383.Following the lead of the extensive literature, this paper looks into word length, the use of the mostfrequent words and into the use of vowels in each chapter of the book. Given that the featuresselected are categorical, that leads to three contingency tables of ordered rows and therefore tothree sequences of multinomial observations.Section 2 explores these sequences graphically, observing a clear shift in their distribution. Section 3describes the problem of the estimation of a suden change-point in those sequences, in the followingsections we propose various ways to estimate change-points in multinomial sequences; the methodin section 4 involves fitting models for polytomous data, the one in Section 5 fits gamma modelsonto the sequence of Chi-square distances between each row profiles and the average profile, theone in Section 6 fits models onto the sequence of values taken by the first component of thecorrespondence analysis as well as onto sequences of other summary measures like the averageword length. In Section 7 we fit models onto the marginal binomial sequences to identify thefeatures that distinguish the chapters before and after that boundary. Most methods rely heavilyon the use of generalized linear models

Agriculture, technological change and environmental sustainability: Looking for a win-win water policy strategy

This paper analyses the effects that technological changes in agriculture would have on environmental, social and economic indicators. Specifically, our study is focused on two alternative technological improvements: the modernization of water transportation systems versus the increase in the total factor productivity of agriculture. Using a computable general equilibrium model for the Catalan economy, our results suggest that a water policy that leads to greater economic efficiency is not necessarily optimal if we consider social or environmental criteria. Moreover, improving environmental sustainability depends less on the type of technological change than on the institutional framework in which technological change occurs. Keywords: agricultural technological changes, computable general equilibrium model, economic impact, water policy

The EU ‘2020 Energy Initiative’: The post-Lisbon pattern of change in EU energy policy

El novembre de 2010, la Comissió Europea ha finalment donat a conèixer la seva "Energia 2020 Comunicació", un document estratègic en el marc més ampli del programa "Europa 2020". Una estratègia per al desenvolupament sostenible intel · ligent, i creixement inclusiu posa les bases d'un nou enfocament a la política d'energia a la UE. En el marc d'Europa 2020, la Iniciativa d'Energia recopila els resultats que ja s'han obtingut a través de la Estratègia de Lisboa 2000-2010, s'identifiquen les deficiències del passat i i introdueix nous objectius ambiciosos per a la UE en matèria de política energètica.