Using network science to analyze football passing networks: dynamics, space, time and the multilayer nature of the game

From the diversity of applications of Network Science, in this Opinion Paper we are concerned about its potential to analyze one of the most extended group sports: Football (soccer in U.S. terminology). As we will see, Network Science allows addressing different aspects of the team organization and performance not captured by classical analyses based on the performance of individual players. The reason behind relies on the complex nature of the game, which, paraphrasing the foundational paradigm of complexity sciences "can not be analyzed by looking at its components (i.e., players) individually but, on the contrary, considering the system as a whole" or, in the classical words of after-match interviews "it's not just me, it's the team".Comment: 7 pages, 1 figur

Mi corazoncito se quería quedar: everyday transnationalism among undocumented Mexican migrants in the USA and their kin in Mexico

This thesis reports on an ethnographic investigation of the everyday lives of Mexican transnational families living in the USA and Mexico. It gives an account of how migrants and their families who stayed behind experienced and coped with separations and how they negotiated, maintained and continually redefined their family relationships and emotional exchanges. I look at, compare and analyse the experiences of undocumented migrants and non-migrants from both a small town and from a city, for whom migration was, respectively, a long-standing tradition or a fairly recent way of life. The observations herein discussed draw from more than seven months of multi sited participant observation and interview research in two locations in the USA − in Texas and California − as well as in both a small town and two cities in Mexico from where the immigrant cohorts originated (and to where some migrants occasionally returned). The participants were ‘snowballed’ from the families of two cohorts of first-generation undocumented Mexican migrants in these locations. These cohorts differed mainly in their demographic origin (rural/urban), social class (working-class/middle-class origins in Mexico), level of education (basic/high school and higher) and modes of crossing (entry without inspection/visa overstayers). The social and cultural differences between the participants resulted in contrasting self-perceptions and meanings given to their everyday lived experiences as undocumented / ‘illegal’ migrants, to the efforts made for their loved ones, to their identities as ‘camouflaged’ migrants or as people living ‘ambivalent loyalties’. The above named topics are analysed in the framework of transnational family life taking into account the interplay of gender relations, demographic origin, social class, level of education, use of social networks and undocumented status

Large-scale unsupervised spatio-temporal semantic analysis of vast regions from satellite images sequences

Temporal sequences of satellite images constitute a highly valuable and abundant resource for analyzing regions of interest. However, the automatic acquisition of knowledge on a large scale is a challenging task due to different factors such as the lack of precise labeled data, the definition and variability of the terrain entities, or the inherent complexity of the images and their fusion. In this context, we present a fully unsupervised and general methodology to conduct spatio-temporal taxonomies of large regions from sequences of satellite images. Our approach relies on a combination of deep embeddings and time series clustering to capture the semantic properties of the ground and its evolution over time, providing a comprehensive understanding of the region of interest. The proposed method is enhanced by a novel procedure specifically devised to refine the embedding and exploit the underlying spatio-temporal patterns. We use this methodology to conduct an in-depth analysis of a 220 km2 region in northern Spain in different settings. The results provide a broad and intuitive perspective of the land where large areas are connected in a compact and well-structured manner, mainly based on climatic, phytological, and hydrological factors

On-off switch of charge-separated states of pyridine-vinylene-linked porphyrin-C60 conjugates detected by EPR

The design, synthesis, and electronic properties of a new series of D–π–A conjugates consisting of free base (H2P) and zinc porphyrins (ZnP) as electron donors and a fullerene (C60) as electron acceptor, in which the two electroactive entities are covalently linked through pyridine-vinylene spacers of different lengths, are described. Electronic interactions in the ground state were characterized by electrochemical and absorption measurements, which were further supported with theoretical calculations. Most importantly, charge-transfer bands were observed in the absorption spectra, indicating a strong push–pull behavior. In the excited states, electronic interactions were detected by selective photoexcitation under steady-state conditions, by time-resolved fluorescence investigations, and by pump probe experiments on the femto-, pico-, and nanosecond time scales. Porphyrin fluorescence is quenched for the different D–π–A conjugates, from which we conclude that the deactivation mechanisms of the excited singlet states are based on photoinduced energy- and/or electron transfer processes between H2P/ZnP and C60, mediated through the molecular spacers. The fluorescence intensity decreases and the fluorescence lifetimes shorten as the spacer length decreases and as the spacer substitution changes. With the help of transient absorption spectroscopy, the formation of charge-separated states involving oxidized H2P/ZnP and reduced C60 was confirmed. Lifetimes of the corresponding charge-separated states, which ranged from ∼400 picoseconds to 165 nanoseconds, depend on the spacer length, the spacer substitution, and the solvent polarity. Interestingly, D–π–A conjugates containing the longest linkers did not necessarily exhibit the longest charge-separated state lifetimes. The distances between the electron donors and the acceptors were calculated by molecular modelling. The longest charge-separated state lifetime corresponded to the D–π–A conjugate with the longest electron donor–acceptor distance. Likewise, EPR measurements in frozen media revealed charge separated states in all the D–π–A conjugates investigated. A sharp peak with g values ∼2.000 was assigned to reduced C60, while a broader, less intense signal (g ∼ 2.003) was assigned to oxidized H2P/ZnP. On–off switching of the formation and decay of the charge-separated states was detected by EPR at 77 K by repeatedly turning the irradiation source on and off