Showing papers by "University of Lleida published in 2012"

Modeling river bed morphology, roughness, and surface sedimentology using high resolution terrestrial laser scanning

Abstract: [1] Recent advances in technology have revolutionized the acquisition of topographic data, offering new perspectives on the structure and morphology of the Earth's surface. These developments have had a profound impact on the practice of river science, creating a step change in the dimensionality, resolution, and precision of fluvial terrain models. The emergence of “hyperscale” survey methods, including structure from motion photogrammetry and terrestrial laser scanning (TLS), now presents the opportunity to acquire 3-D point cloud data that capture grain-scale detail over reach-scale extents. Translating these data into geomorphologically relevant products is, however, not straightforward. Unlike traditional survey methods, TLS acquires observations rapidly and automatically, but unselectively. This results in considerable “noise” associated with backscatter from vegetation and other artifacts. Moreover, the large data volumes are difficult to visualize; require very high capacity storage; and are not incorporated readily into GIS and simulation models. In this paper we analyze the geomorphological integrity of multiscale terrain models rendered from a TLS survey of the braided River Feshie, Scotland. These raster terrain models are generated using a new, computationally efficient geospatial toolkit: the topographic point cloud analysis toolkit (ToPCAT). This performs an intelligent decimation of point cloud data into a set of 2.5-D terrain models that retain information on the high-frequency subgrid topography, as the moments of the locally detrended elevation distribution. The results quantify the degree of terrain generalization inherent in conventional fluvial DEMs and illustrate how subgrid topographic statistics can be used to map the spatial pattern of particle size, grain roughness, and sedimentary facies at the reach scale.

Analysis and application of gamification

Abstract: In this paper we present a method for analysis and application of gamification as a tool to assist the participation and motivation of people in carrying out various tasks and activities. We analyze what are the psychological and social motivations of human beings, and how game mechanics can help when it comes to satisfy these needs. Likewise, it is proposed a method for analyzing the effectiveness of gamification based on a quality service model and the metrics associated with the properties of the playability as a measure of fun induced by the process of gamification.

Playability: analysing user experience in video games

Abstract: Currently, few studies focus on analysing the degree of the Player eXperience PX in video games. Video games have now become interactive entertainment systems with a high economic impact on society; these are interactive systems characterised by their subjectivity, which differ from other systems in that their main objective is to entertain and amuse the user player. This work discusses the analysis and evaluation of the User eXperience UX in interactive entertainment systems, exploring how usability, given its definition, objectives and the fact it is one of the main dimensions of UX, is not sufficient to characterise the PX, giving rise to a new concept: Playability. In this paper, we present a framework for the analysis and evaluation of the UX in video games. The results show the need and importance of a framework to help us understand and measure the experience that players feel using these types of interactive systems, in order to improve the experience during play time. The proposed framework characterises the experience using attributes to identify and properties to measure UX. It thus provides a multifaceted analysis mechanism to assess the impact of the gaming experience and its relationship with the elements of a video game. We therefore present a system to represent UX based on this framework, with the aim of ensuring and measuring a satisfactory experience of the entertainment system. Finally, we discuss a practical experiment in which an evaluation of the playability of a commercial video game was carried out using the methods proposed in this work.

Support for solar PV deployment in Spain: Some policy lessons

Abstract: This paper provides an overview of the trends of the Spanish solar PV feed-in tariff (FIT) and its design elements, identifies some implications for the effective and cost-efficient deployment of solar PV in Spain and infers some lessons which might be useful for the implementation of support for solar PV elsewhere. Our analysis is based on a throughout revision of the relevant legislation, official data on deployment and related expenditure, informal discussions with key stakeholders and written documents. Several key design elements within FITs that should be implemented and other elements that should be avoided in order to have an effective and cost-efficient promotion of solar PV are identified. All in all, the specific design elements to be included are clearly contingent upon the preferences and priorities of policymakers.

Modelling the effects of sanitary policies on European vulture conservation

Abstract: Biodiversity losses are increasing as a consequence of negative anthropogenic effects on ecosystem dynamics. However, the magnitude and complexity of these effects may still be greatly underestimated. Most Old World vultures have experienced rapid population declines in recent years. In Europe, their immediate conservation depends on changes in health regulations affecting the availability of food provided by domestic carcasses. Information is lacking on the effects of a hypothetical food shortage on the population dynamics of vultures, and is necessary to assess the potential impacts of policy decisions on future changes in biodiversity and ecosystem services. A novel computational model (P-systems) was used to model these effects, forecasting a rapid decline in the Eurasian griffon vulture (Gyps fulvus). By contrast, vulture species with greater plasticity in their dietary range appeared less sensitive to declining food availability. This study extends our understanding of vulture ecosystem services, which have social and economic implications.

Melanoidins Formed by Maillard Reaction in Food and Their Biological Activity

Abstract: This paper is a review of the recent studies on Maillard reaction products, the formation mechanism for these compounds and melanoidin structure, the undesirable consequences in food especially in fruit juice processing, the desirable effects and the biological properties related to the beneficial health. Melanoidins are compounds generated in the late stages of the Maillard reaction from reducing sugars and proteins or amino acids during food processing and preservation. Recently, the effects of melanoidins on human health and the chemical characterization of the beneficial components have gained a lot of attention, and their implications on several levels, sensory, nutritional, toxicological and technological were investigated. Food melanoidins have been reported to be anionic, coloured compounds, and some of their key chromophores have been elucidated. The antioxidant activity and other biological effects of melanoidins from real foods and model systems have been widely studied. Despite this, very few different melanoidin structures have actually been described, and specific health effects have yet to be linked with chemically distinct melanoidins. The variety of Maillard reaction products formed during the reaction, in conjunction with the difficulty in purifying and identifying them, makes a thorough analysis of melanoidins challenging.

Dynamics of the game in soccer: Detection of T-patterns

Abstract: Traditional approaches to the quantification of team sports have proved to be limited in their ability to identify complex structural regularities that, despite being unobservable, nonetheless underlie the development of the sporting contest between opposing teams. This paper describes a method for detecting the dynamics of play in professional soccer through the analysis of temporal patterns (T-patterns). The observation instrument used was SOF-5, which is especially designed for studying the dynamics of the game in soccer. The recording consisted of within-session monitoring using the MATCH VISION STUDIO 3.0 software, while the THEME software was used to detect and analyse T-patterns. These T-patterns revealed regularities in the playing style of the observed team, FC Barcelona. The structures detected included a ball possession pattern, whereby the ball was first kept in the central zone before being played forward, through several moves, into the zones closest to the opposing team's goal in o...

Social support (family and supervisor), work–family conflict, and burnout: Sex differences

Abstract: We examined how work-family conflict (WFC) mediated the relationship between social support (supervisor and family) and burnout, and how sex moderated this relationship (N = 343 Spanish workers). The results sustained hypotheses in accordance with a biosocial model of sex differences. There were full mediation effects of work interference with family (WIF) in the association of work support with burnout for men, and of family support with burnout for women. This suggests that sex moderated these mediation processes. The findings are discussed in terms of a shift in the differential assignment of family roles to men and women, despite the fact that women might be the main contributors to domestic work and related tasks.

Cellular Dysfunction in Diabetes as Maladaptive Response to Mitochondrial Oxidative Stress

Abstract: Oxidative stress has been implicated in diabetes long-term complications. In this paper, we summarize the growing evidence suggesting that hyperglycemia-induced overproduction of superoxide by mitochondrial electron transport chain triggers a maladaptive response by affecting several metabolic and signaling pathways involved in the pathophysiology of cellular dysfunction and diabetic complications. In particular, it is our goal to describe physiological mechanisms underlying the mitochondrial free radical production and regulation to explain the oxidative stress derived from a high intracellular glucose concentration and the resulting maladaptive response that leads to a cellular dysfunction and pathological state. Finally, we outline potential therapies for diabetes focused to the prevention of mitochondrial oxidative damage.

Metabolic syndrome, insulin resistance and sleepiness in real-life obstructive sleep apnoea

Abstract: The metabolic syndrome shows a variable prevalence in obstructive sleep apnoea (OSA), and its association with insulin resistance or excessive daytime sleepiness in OSA is unclear. This study assessed the following in consecutive patients with newly diagnosed OSA: 1) the prevalence of metabolic syndrome; and 2) its association with insulin resistance and daytime sleepiness. Metabolic syndrome (National Cholesterol Education Program Adult Treatment Panel (NCEP-ATP) III criteria), insulin resistance (Homeostatic Model Assessment (HOMA) index, n = 288) and daytime sleepiness (Epworth Sleepiness Scale) were assessed in 529 OSA patients. The prevalence of metabolic syndrome was 51.2%, which increased with OSA severity. Each metabolic syndrome component correlated with apnoea/hypopnoea index, but only blood pressure retained significance after correction for confounders. Both obesity and OSA contributed to metabolic abnormalities, with different sex-related patterns, since diagnosis of metabolic syndrome was significantly associated with neck circumference, age, body mass index and lowest arterial oxygen saturation in males, and with age and arousal index in females. The number of metabolic syndrome components increased with HOMA index (p<0.001). Prevalence of sleepiness was the same in patients with and without metabolic syndrome. The metabolic syndrome occurs in about half of "real-life" OSA patients, irrespective of daytime sleepiness, and is a reliable marker of insulin resistance.

Through‐water terrestrial laser scanning of gravel beds at the patch scale

Abstract: Acquiring high resolution topographic data of natural gravel surfaces is technically demanding in locations where the bed is not exposed at low water stages. Often the most geomorphologically active surfaces are permanently submerged. Gravel beds are spatially variable and measurement of their detailed structure and particle sizes is essential for understanding the interaction of bed roughness with near-bed flow hydraulics, sediment entrainment, transport and deposition processes, as well as providing insights into the ecological responses to these processes. This paper presents patch-scale laboratory and field experiments to demonstrate that through-water terrestrial laser scanning (TLS) has the potential to provide high resolution digital elevation models of submerged gravel beds with enough detail to depict individual grains and small-scale forms. The resulting point cloud data requires correction for refraction before registration. Preliminary validation shows that patch-scale TLS through 200 mm of water introduces a mean error of less than 5 mm under ideal conditions. Point precision is not adversely affected by the water column. The resulting DEMs can be embedded seamlessly within larger sub-aerial reach-scale surveys and can be acquired alongside flow measurements to examine the effects of three-dimensional surface geometry on turbulent flow fields and their interaction with instream ecology dynamics. Copyright © 2011 John Wiley & Sons, Ltd.

β-Catenin Signalling in Glioblastoma Multiforme and Glioma-Initiating Cells.

Abstract: Glioblastoma multiforme (GBM) is a commonly occurring brain tumor with a poor prognosis. GBM can develop both “de novo” or evolve from a previous astrocytoma and is characterized by high proliferation and infiltration into the surrounding tissue. Following treatment (surgery, radiotherapy, and chemotherapy), tumors often reappear. Glioma-initiating cells (GICs) have been identified in GBM and are thought to be responsible for tumors initiation, their continued growth, and recurrence. β-catenin, a component of the cell-cell adhesion complex and of the canonical Wnt pathway, regulates proliferation, adhesion, and migration in different cell types. β-catenin and components of the Wnt canonical pathway are commonly overexpressed in GBM. Here, we review previous work on the role of Wnt/β-catenin signalling in glioma initiation, proliferation, and invasion. Understanding the molecular mechanisms regulating GIC biology and glioma progression may help in identifying novel therapeutic targets for GBM treatment.

Review of Solar Thermal Storage Techniques and Associated Heat Transfer Technologies

Abstract: Thermal energy storage is a key component of solar power plants if dispatchability is required. On the other hand, although different systems and many materials are available, only a few plants in the world have tested thermal energy storage systems. Here, all materials considered in literature and/or used in real plants are listed, the different systems are described and analyzed, and real experiences are compiled. The associated heat transfer technologies to support and improve these systems are described and analyzed.

A novel source for miR-21 expression through the alternative polyadenylation of VMP1 gene transcripts

Abstract: miR-21 is the most commonly over-expressed microRNA (miRNA) in cancer and a proven oncogene. Hsa-miR-21 is located on chromosome 17q23.2, immediately downstream of the vacuole membrane protein-1 (VMP1) gene, also known as TMEM49. VMP1 transcripts initiate ∼ 130 kb upstream of miR-21, are spliced, and polyadenylated only a few hundred base pairs upstream of the miR-21 hairpin. On the other hand, primary miR-21 transcripts (pri-miR-21) originate within the last introns of VMP1, but bypass VMP1 polyadenylation signals to include the miR-21 hairpin. Here, we report that VMP1 transcripts can also bypass these polyadenylation signals to include miR-21, thus providing a novel and independently regulated source of miR-21, termed VMP1-miR-21. Northern blotting, gene-specific RT-PCR, RNA pull-down and DNA branching assays support that VMP1-miR-21 is expressed at significant levels in a number of cancer cell lines and that it is processed by the Microprocessor complex to produce mature miR-21. VMP1 and pri-miR-21 are induced by common stimuli, such as phorbol-12-myristate-13-acetate (PMA) and androgens, but show differential responses to some stimuli such as epigenetic modifying agents. Collectively, these results indicate that miR-21 is a unique miRNA capable of being regulated by alternative polyadenylation and two independent gene promoters.