Red rains as major contributors of nutrients and alkalinity to terrestrial ecosystems at Montseny (NE Spain)

During two years (1983-1985), 8 red rains were collected in the Montseny mountains. The suspended matter contained in red rains has its source in the Sahara desert and corresponds to fine silts. Due to the calcite content of dust responsible for the red rains, these rains are alkaline with a volume weighted mean pH of 7.7 versus 4.7 of non-red rains. Estimated HCO; alkalinity input due to red rains is 0.21 keqlhalyr and total annual HCO; alkalinity input is 0.24 keqlhalyr. To that figure, one has to add at least 0.24 keqlhalyr due to the alkalinity of calcite contained in red dust. For the same period, hydrogen input in bulk deposition amounts to 0.19 keqlhalyr. These results indicate that acidity due to non-red rain espisodes is neutralized on an annual basis, with red rains being the major neutralizing agent. Ion concentrations in red rains are high, which makes them an important source of nutrients even though they only account for 5.4% of annual preci itation. Red rains are particularly enriched with ca2+ having a P+ volume-weighted mean Ca concentration 14 times higher than non-red rains and delivering 46% of the annual inputs of soluble ca2+ in bulk precipitation at Montseny.Durant dos anys (1983-1985) es varen recollir 8 pluges de fang a La Castanya (Montseny). La matèria particulada de les pluges de fang s'origina al desert del Sahara, i correspon a llims fins. Degut al contingut de calcita d'aquests llims, les pluges de fang són alcalines, amb un pH mig de 7.7, enfront de 4.7 per la resta de les pluges. L'entrada anual estimada d'alcalinitat en forma de bicarbonat dissolt a les pluges de fang és de 0.21 keq/ha/any, d'un total estimat de 0.24 keq/ha/any per totes les pluges. A aquesta xifra cal afegir almenys 0.24 keq/ha/any degut al contingut de calcita a la fase sblida de les pluges de fang. Durant el mateix període, l'entrada d'hidrogenions a la deposició global és de 0.19 keq/ha/any. Aquests resultats indiquen que, a escala anual, les pluges de fang aporten suficient alcalinitat com per neutralitzar I'acidesa de la resta de les pluges. Les concentracions iòniques són elevades a les pluges de fang, i aquestes són per tant, un factor important en la deposició atmosfkrica de nutrients, encara que representen en promig només un 5.4% de la precipitació anual. Les pluges de fang són particularment riques en calci: la seva concentració mitjana ponderada d'aquest element és 14 vegades més gran que la de la resta de les pluges, i contribueixen amb un 46% a les entrades anuals de calci en la deposició global del Montseny

Ca impurity in small mixed 4^4He-3^3He clusters

The structure of small mixed helium clusters doped with one calcium atom has been determined within the diffusion Monte Carlo framework. The results show that the calcium atom sits at the $^4$He-$^3$He interface. This is in agreement with previous studies, both experimental and theoretical, performed for large clusters. A comparison between the results obtained for the largest cluster we have considered for each isotope shows a clear tendency of the Ca atom to reside in a deep dimple at the surface of the cluster for $^4$He clusters, and to become fully solvated for $^3$He clusters. We have calculated the absorption spectrum of Ca around the $4s4p \leftarrow 4s^2$ transition and have found that it is blue-shifted from that of the free-atom transition by an amount that depends on the size and composition of the cluster.Comment: 24 pages, 11 figures. Accepted on Journal of Chemical Physic

Finding iteration patterns in dynamic Web page authoring

The final publication is available at Springer via http://dx.doi.org/10.1007/11431879_10Revised Selected Papers of the Joint Working Conferences EHCI-DSVIS 2004, Hamburg, Germany, July 11-13, 2004Most of the current WWW is made up of dynamic pages. The development of dynamic pages is a difficult and costly endeavour, out-of-reach for most users, experts, and content producers. We have developed a set of techniques to support the edition of dynamic web pages in a WYSIWYG environment. In this paper we focus on specific techniques for inferring changes to page generation procedures from users actions on examples of the pages generated by these procedures. More specifically, we propose techniques for detecting iteration patterns in users’ behavior in web page editing tasks involving page structures like lists, tables and other iterative HTML constructs. Such patterns are used in our authoring tool, DESK, where a specialized assistant, DESK-A, detects iteration patterns and generates, using Programming by Example, a programmatic representation of the user’s actions. Iteration patterns help obtain a more detailed characterization of users’ intent, based on user monitoring techniques, that is put in relation to application knowledge automatically extracted by our system from HTML pages. DESK-A relieves end-users from having to learn programming and specification languages for editing dynamic-generated web pages.The work reported in this paper is being supported by the Spanish Ministry of Science and Technology (MCyT), project number TIC2002-194

Impressions in Recommender Systems: Present and Future

Impressions are a novel data source providing researchers and practitioners with more details about user interactions and their context. In particular, an impression contain the items shown on screen to users, alongside users' interactions toward such items. In recent years, interest in impressions has thrived, and more papers use impressions in recommender systems. Despite this, the literature does not contain a comprehensive review of the current topics and future directions. This work summarizes impressions in recommender systems under three perspectives: recommendation models, datasets with impressions, and evaluation methodologies. Then, we propose several future directions with an emphasis on novel approaches. This work is part of an ongoing review of impressions in recommender systems

Traumatic Tympanic Bulla Fracture in a Cat With Severe Head Trauma

A nine-year-old male European shorthair cat was referred to our practice with severe head trauma after suffering a road traffic accident (RTA). The patient presented marked facial swelling and multiple skin wounds and bruising, inspiratory dyspnea, palpable mandibular and maxillary fractures, serosanguinolent oronasal discharge and right eye exophthalmos and buphthalmos with loss of menace and pupillary reflex. After stabilizing the patient, a CT scan was performed under general anesthesia and an oesophagostomy tube was placed. The scan revealed the presence of multiple right tympanic bulla fractures. Multiple mandibular, maxillary, and palatine fractures were also present. The cat underwent surgery. Mandibular symphyseal separation and maxillary fractures were stabilized using intraoral cerclage wire fixation reinforced with composite and the right eye was enucleated. The rest of the fractures were treated conservatively. A CT scan 4 months after the trauma was also performed. At this point, the maxillofacial fractures were healing properly, and a bone callus demonstrating fusion of fragments of the right tympanic bulla was evident. There was absence of abnormal content inside the right tympanic bulla. The patient recovered uneventfully with no neurological deficits. To the author''s knowledge this is the first case reporting a traumatic tympanic bulla fracture in the cat with case follow up, and the first case reported using CT as diagnostic imaging test

Characterizing Impression-Aware Recommender Systems

Impression-aware recommender systems (IARS) are a type of recommenders that learn user preferences using their interactions and the recommendations (also known as impressions) shown to users. The community’s interest in this type of recommenders has steadily increased in recent years. To aid in characterizing this type of recommenders, we propose a theoretical framework to define IARS and classify the recommenders present in the state-of-the-art. We start this work by defining core concepts related to this type of recommenders, such as impressions and user feedback. Based on this theoretical framework, we identify and define three properties and three taxonomies that characterize IARS. Lastly, we undergo a systematic literature review where we discover and select papers belonging to the state-of-the-art. Our review analyzes papers under the properties and taxonomies we propose; we highlight the most and least common properties and taxonomies used in the literature, their relations, and their evolution over time, among others

Smith-Purcell radiation emission in aperiodic arrays

We study the Smith-Purcell light emission produced by electrons moving parallel to linear aperiodic particle arrays. This constitutes a generalization of this type of phenomenon from periodic to aperiodic structures. As in the periodic case, the emission is found to exhibit intense features in its angular and frequency distributions, associated with the condition of constructive interference between the contributions arising from different particles in the array. This condition can also be expressed in terms of momentum conservation involving reciprocal wave-vector transfers from the array. We consider two examples of quasiperiodic and hyperuniform aperiodic arrays that allow us to illustrate this idea. Our study provides insight into the interaction of fast electrons with aperiodic arrays characterized by strong features in reciprocal space, which dominate the electron-array coupling.Postprint (published version

Obstacle detection and avoidance on sidewalks

We present part of a vision system for blind and visually impaired people. It detects obstacles on sidewalks and provides guidance to avoid them. Obstacles are trees, light poles, trash cans, holes, branches, stones and other objects at a distance of 3 to 5 meters from the camera position. The system first detects the sidewalk borders, using edge information in combination with a tracking mask, to obtain straight lines with their slopes and the vanishing point. Once the borders are found, a rectangular window is defined within which two obstacle detection methods are applied. The first determines the variation of the maxima and minima of the gray levels of the pixels. The second uses the binary edge image and searches in the vertical and horizontal histograms for discrepancies of the number of edge points. Together, these methods allow to detect possible obstacles with their position and size, such that the user can be alerted and informed about the best way to avoid them. The system works in realtime and complements normal navigation with the cane

Competitiveness and sustainability: can ‘smart city regionalism’ square the circle?

Increasingly, the widely established, globalisation-driven agenda of economic competitiveness meets a growing concern with sustainability. Yet, the practical and conceptual co-existence—or fusion—of these two agendas is not always easy. This includes finding and operationalising the ‘right’ scale of governance, an important question for the pursuit of the distinctly transscalar nature of these two policy fields. ‘New regionalism’ has increasingly been discussed as a pragmatic way of tackling the variable spatialities associated with these policy fields and their changing articulation. This paper introduces ‘smart (new) city-regionalism’, derived from the principles of smart growth and new regionalism, as a policy-shaping mechanism and analytical framework. It brings together the rationales, agreed principles and legitimacies of publicly negotiated polity with collaborative, network-based and policy-driven spatiality. The notion of ‘smartness’, as suggested here as central feature, goes beyond the implicit meaning of ‘smart’ as in ‘smart growth’. When introduced in the later 1990s the term embraced a focus on planning and transport. Since then, the adjective ‘smart’ has become used ever more widely, advocating innovativeness, participation, collaboration and co-ordination. The resulting ‘smart city regionalism’ is circumscribed by the interface between the sectorality and territoriality of policy-making processes. Using the examples of Vancouver and Seattle, the paper looks at the effects of the resulting specific local conditions on adopting ‘smartness’ in the scalar positioning of policy-making