Compositional data and Simpson's paradox

Simpson's paradox, also known as amalgamation or aggregation paradox, appears whendealing with proportions. Proportions are by construction parts of a whole, which canbe interpreted as compositions assuming they only carry relative information. TheAitchison inner product space structure of the simplex, the sample space of compositions, explains the appearance of the paradox, given that amalgamation is a nonlinearoperation within that structure. Here we propose to use balances, which are specificelements of this structure, to analyse situations where the paradox might appear. Withthe proposed approach we obtain that the centre of the tables analysed is a naturalway to compare them, which avoids by construction the possibility of a paradox.Key words: Aitchison geometry, geometric mean, orthogonal projection

A Homogeneous Set-Theoretical Frame for Clustering Fuzzy Relational Data

Our purpose is to provide a set-theoretical frame to clustering fuzzy relational data basically based on cardinality of the fuzzy subsets that represent objects and their complementaries, without applying any crisp property. From this perspective we define a family of fuzzy similarity indexes which includes a set of fuzzy indexes introduced by Tolias et al, and we analyze under which conditions it is defined a fuzzy proximity relation. Following an original idea due to S. Miyamoto we evaluate the similarity between objects and features by means the same mathematical procedure. Joining these concepts and methods we establish an algorithm to clustering fuzzy relational data. Finally, we present an example to make clear all the process

Some biological data on cetaceans populations present in the western coasts of Ireland

Ireland’s waters constitute one of the richest habitats for cetaceans in Europe. Marine mammals, particularly cetaceans, are known to be definitive hosts of digestive parasites from the Fm.Anisakidae. The main aim of this study is to collect and compile all the information available out there regarding parasites of the Fm. Anisakidae and their definitive hosts. Secondary objectives are to relate the presence of cetacean species with the presence of parasites of the Fm. Anisakidae and to determine whether this greater number of cetaceans relates to a greater level of parasitism. Prevalence and burdens of anisakids in definitive hosts vary widely with host species, geographic location, and season. Results from several post-mortem exams are given. However, they cannot be compared due to differences in collecting techniques. Anisakis simplex is the most commonly and widespread parasite found in the majority of the samples and in a majornumber of hosts, which include harbour porpoise, short-beaked common dolphin and bottlenose dolphin. Studies on harbour porpoise obtained prevalences of Anisakis spp. of 46% (n=26) and of 100% (n= 12). Another study in common dolphin reported a prevalence of 68% (n=25). Several reasons could influence the variations in the presence of Anisakis. Studies on commerciallyexploited fish have reported prevalences of Anisakis simplex ranging from 65-100% in wildAtlantic salmon and from 42-53.4% in Atlantic cod

ICOS Carbon Data Portal

La infraestructura europea ICOS (Integrated Carbon Observation System), tiene como misión proveer de mediciones de gases de efecto invernadero a largo plazo, lo que ha de permitir estudiar el estado actual y comportamiento futuro del ciclo global del carbono. En este contexto, geomati.co ha desarrollado un portal de búsqueda y descarga de datos que integra las mediciones realizadas en los ámbitos terrestre, marítimo y atmosférico, disciplinas que hasta ahora habían gestionado los datos de forma separada. El portal permite hacer búsquedas por múltiples ámbitos geográficos, por rango temporal, por texto libre o por un subconjunto de magnitudes, realizar vistas previas de los datos, y añadir los conjuntos de datos que se crean interesantes a un “carrito” de descargas. En el momento de realizar la descarga de una colección de datos, se le asignará un identificador universal que permitirá referenciarla en eventuales publicaciones, y repetir su descarga en el futuro (de modo que los experimentos publicados sean reproducibles). El portal se apoya en formatos abiertos de uso común en la comunidad científica, como el formato NetCDF para los datos, y en el perfil ISO de CSW, estándar de catalogación y búsqueda propio del ámbito geoespacial. El portal se ha desarrollado partiendo de componentes de software libre existentes, como Thredds Data Server, GeoNetwork Open Source y GeoExt, y su código y documentación quedarán publicados bajo una licencia libre para hacer posible su reutilización en otros proyecto