University of Alcalá

About: University of Alcalá is a education organization based out in Alcalá de Henares, Spain. It is known for research contribution in the topics: Population & Receptor. The organization has 10795 authors who have published 20718 publications receiving 410089 citations. The organization is also known as: University of Alcala & University of Alcala de Henares.

Dataset-driven research for improving recommender systems for learning

Abstract: In the world of recommender systems, it is a common practice to use public available datasets from different application environments (e.g. MovieLens, Book-Crossing, or Each-Movie) in order to evaluate recommendation algorithms. These datasets are used as benchmarks to develop new recommendation algorithms and to compare them to other algorithms in given settings. In this paper, we explore datasets that capture learner interactions with tools and resources. We use the datasets to evaluate and compare the performance of different recommendation algorithms for learning. We present an experimental comparison of the accuracy of several collaborative filtering algorithms applied to these TEL datasets and elaborate on implicit relevance data, such as downloads and tags, that can be used to improve the performance of recommendation algorithms.

Specificity and differential object marking in Spanish

Abstract: The use of the preposition a with direct objects in Spanish is a well known instance of the general phenomenon of Differential Object Marking (DOM). In Spanish grammars the insertion of a is usually presented as dependent on two basic factors: animacy and referentiality/specificity. The correlation between the object marker and specificity is not systematic, basically because animacy —and not specificity— is the dominant trigger for DOM in Spanish, but a number of facts still indicate that the presence of a tends to be associated with specific readings. In order to account for these facts without positing any [+specific] feature in the linguistic meaning of a, I try to show that it contributes to utterance interpretation as an internal topic marker. This seems to be the simplest way to derive «specificity effects», and to account for the crosslinguistic similarities between DOM and other grammatical phenomena (topicalization, clitic doubling, scrambling).

Multispecies comparison reveals that invasive and native plants differ in their traits but not in their plasticity

Abstract: Summary 1. Plastic responses to spatiotemporal environmental variation strongly influence species distribution, with widespread species expected to have high phenotypic plasticity. Theoretically, high phenotypic plasticity has been linked to plant invasiveness because it facilitates colonization and rapid spreading over large and environmentally heterogeneous new areas. 2. To determine the importance of phenotypic plasticity for plant invasiveness, we compare well-known exotic invasive species with widespread native congeners. First, we characterized the phenotype of 20 invasive–native ecologically and phylogenetically related pairs from the Mediterranean region by measuring 20 different traits involved in resource acquisition, plant competition ability and stress tolerance. Second, we estimated their plasticity across nutrient and light gradients. 3. On average, invasive species had greater capacity for carbon gain and enhanced performance over a range of limiting to saturating resource availabilities than natives. However, both groups responded to environmental variations with high albeit similar levels of trait plasticity. Therefore, contrary to the theory, the extent of phenotypic plasticity was not significantly higher for invasive plants. 4. We argue that the combination of studying mean values of a trait with its plasticity can render insightful conclusions on functional comparisons of species such as those exploring the performance of species coexisting in heterogeneous and changing environments.