2,994 research outputs found

    Localization Operators and an Uncertainty Principle for the Discrete Short Time Fourier Transform

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    Localization operators in the discrete setting are used to obtain information on a signal f from the knowledge on the support of its short time Fourier transform. In particular, the extremal functions of the uncertainty principle for the discrete short time Fourier transform are characterized and their connection with functions that generate a time-frequency basis is studied

    Educational Uses of Augmented Reality (AR): Experiences in Educational Science

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    Augmented Reality (AR) is an emerging technology that is gaining greater influence on teaching every day. AR, together with mobile technology, is defined as one of the most efficient pairs for supporting significant and ubiquitous learning. Purpose of the study: the Instructional Material Motivational Survey (IMMS), by Keller, was used to determine the degree of motivation possessed by the Pedagogy students on the utilization of the notes enriched with AR in the classroom, available for their didactic use through mobile devices. Methods: through an app designed for the courses Education Technology (ET) and Information and Communication Technologies (ICT) Applied to Education, the motivation gained when participating in this experience, and how it influences the improvement of academic performance, was evaluated. Results and conclusions: the most notable main result was finding a strong relationship between the motivation of the students when using the enriched notes and the increase of performance in the academic subject where it was used. Likewise, it was proved that the use of Augmented Reality benefited the learning process itself

    Quasi-Perfect Lee Codes of Radius 2 and Arbitrarily Large Dimension

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    A construction of two-quasi-perfect Lee codes is given over the space ?np for p prime, p ? ±5 (mod 12), and n = 2[p/4]. It is known that there are infinitely many such primes. Golomb and Welch conjectured that perfect codes for the Lee metric do not exist for dimension n ? 3 and radius r ? 2. This conjecture was proved to be true for large radii as well as for low dimensions. The codes found are very close to be perfect, which exhibits the hardness of the conjecture. A series of computations show that related graphs are Ramanujan, which could provide further connections between coding and graph theories

    Trace elements and C and N isotope composition in two mushroom species from a mine-spill contaminated site

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    Fungi play a key role in the functioning of soil in terrestrial ecosystems, and in particular in the remediation of degraded soils. The contribution of fungi to carbon and nutrient cycles, along with their capability to mobilise soil trace elements, is well-known. However, the importance of life history strategy for these functions has not yet been thoroughly studied. This study explored the soil-fungi relationship of two wild edible fungi, the ectomycorrhizal Laccaria laccata and the saprotroph Volvopluteus gloiocephalus. Fruiting bodies and surrounding soils in a mine-spill contaminated area were analysed. Isotope analyses revealed Laccaria laccata fruiting bodies were 15N-enriched when compared to Volvopluteus gloiocephalus, likely due to the transfer of 15N-depleted compounds to their host plant. Moreover, Laccaria laccata fruiting bodies δ13C values were closer to host plant values than surrounding soil, while Volvopluteus gloiocephalus matched the δ13C composition to that of the soil. Fungal species presented high bioaccumulation and concentrations of Cd and Cu in their fruiting bodies. Human consumption of these fruiting bodies may represent a toxicological risk due to their elevated Cd concentrations

    Cyclodextrin-based multivalent glycodisplays: Covalent and supramolecular conjugates to assess carbohydrate-protein interactions

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    Covalent attachment of biorecognizable sugar ligands in several copies at precise positions of cyclomaltooligosaccharide (cyclodextrin, CD) macrocycles has proven to be an extremely flexible strategy to build multivalent conjugates. The commercial availability of the native CDs in three different sizes, their axial symmetry and the possibility of position- and face-selective functionalization allow a strict control of the valency and spatial orientation of the recognition motifs (glycotopes) in low, medium, high and hyperbranched glycoclusters, including glycodendrimer-CD hybrids. >Click-type> ligation chemistries, including copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC), thiol-ene coupling or thiourea-forming reactions, have been implemented to warrant full homogeneity of the adducts. The incorporation of different glycotopes to investigate multivalent interactions in heterogeneous environments has also been accomplished. Not surprisingly, multivalent CD conjugates have been, and continue to be, major actors in studies directed at deciphering the structural features ruling carbohydrate recognition events. Nanometric glycoassemblies endowed with the capability of adapting the inter-saccharide distances and orientations in the presence of a receptor partner or capable of mimicking the fluidity of biological membranes have been conceived by multitopic inclusion complex formation, rotaxanation or self-assembling. Applications in the fields of sensors, site-specific drug and gene delivery or protein stabilization attest for the maturity of the field.Ministerio de Economı´a y Competitividad CTQ2010-15848, SAF2010-1567

    Wild animals are reservoirs and sentinels of staphylococcus aureus and MRSA clones: A problem with “one health” concern

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    Background: The availability of comprehensive data on the ecology and molecular epidemiology of Staphylococcus aureus/MRSA in wild animals is necessary to understand their relevance in the “One Health” domain. Objective: In this study, we determined the pooled prevalence of nasal, tracheal and/or oral (NTO) Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) carriage in wild animals, with a special focus on mecA and mecC genes as well as the frequency of MRSA and methicillin susceptible S. aureus (MSSA) of the lineages CC398 and CC130 in wild animals. Methodology: This systematic review was executed on cross-sectional studies that reported S. aureus and MRSA in the NTO cavities of wild animals distributed in four groups: non-human primates (NHP), wild mammals (WM, excluding rodents and NHP), wild birds (WB) and wild rodents (WR). Appropriate and eligible articles published (in English) between 1 January 2011 to 30 August 2021 were searched for from PubMed, Scopus, Google Scholar, SciElo and Web of Science. Results: Of the 33 eligible and analysed studies, the pooled prevalence of NTO S. aureus and MRSA carriage was 18.5% (range: 0–100%) and 2.1% (range: 0.0–63.9%), respectively. The pooled prevalence of S. aureus/MRSA in WM, NHP, WB and WR groups was 15.8/1.6, 32.9/2.0, 10.3/3.4 and 24.2/3.4%, respectively. The prevalence of mecC-MRSA among WM/NHP/WB/WR was 1.64/0.0/2.1/0.59%, respectively, representing 89.9/0.0/59.1/25.0% of total MRSA detected in these groups of animals.The MRSA-CC398 and MRSA-CC130 lineages were most prevalent in wild birds (0.64 and 2.07%, respectively); none of these lineages were reported in NHP studies. The MRSA-CC398 (mainly of spa-type t011, 53%), MRSA-CC130 (mainly of spa types t843 and t1535, 73%), MSSA-CC398 (spa-types t571, t1451, t6606 and t034) and MSSA-CC130 (spa types t843, t1535, t3625 and t3256) lineages were mostly reported. Conclusion: Although the global prevalence of MRSA is low in wild animals, mecC-mediated resistance was particularly prevalent among MRSA isolates, especially among WM and WB. Considering the genetic diversity of MRSA in wild animals, they need to be monitored for effective control of the spread of antimicrobial resistance

    "Agenda setting" y crisis económica: influencia de la prensa en el comportamiento de consumo y ahorro

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    The analysis of media influence over society has generated an important interest for social investigators. This paper is focused on potential effects of media into people behaviour. We have followed the “agenda setting” of main spanish newspapers through its contents referred to economic crisis process. This information has determined people consumption and their saving behaviour. The higher the uncertainties about future perspectives, the greater the increase of people savings.El análisis de la influencia de los media sobre la sociedad ha suscitado desde hace años un importante interés por parte de los investigadores. Este trabajo se centra en analizar el posible efecto que sobre el comportamiento de los ciudadanos pueden ejercer los medios de comunicación. en concreto, se trata de observar desde la perspectiva del establecimiento de la agenda (Agenda setting) como los diarios de referencia en España a través de sus contenidos y atención al reciente proceso de crisis económica han condicionado el comportamiento de consumo y ahorro de los hogares, en la medida en que la inclusión de noticias sobre la misma va asociada a una mayor incertidumbre en las perspectivas de futuro y, por tanto, genera un incremento en las tasas de ahorro a costa de un menor consumo presente

    Topological properties of the core group in online communities

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    Online communities are self-organized networks with a clear core-periphery structure, where most of the contributions are due to a small group of users known as the core group. Although several methods for detecting the coreperiphery structure have been proposed, all of them assume a pre-defined structure of the core group. However, online communities exhibit a wide variety of organizations and shapes, and the patterns of behavior of the core group is continuously changing. This paper investigates the relationship between the global parameters of the community and those of the core group. Findings reveal that the behavior of the core group determines the global structure of the community and therefore, the identification of the core group should consider the global characteristics of the network in which they are contributing
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