Ontology-based data access: ontop of databases

We present the architecture and technologies underpinning the OBDA system Ontop and taking full advantage of storing data in relational databases. We discuss the theoretical foundations of Ontop: the tree-witness query rewriting, T-mappings and optimisations based on database integrity constraints and SQL features. We analyse the performance of Ontop in a series of experiments and demonstrate that, for standard ontologies, queries and data stored in relational databases, Ontop is fast, efficient and produces SQL rewritings of high quality

Ontology-based data access with databases: a short course

Ontology-based data access (OBDA) is regarded as a key ingredient of the new generation of information systems. In the OBDA paradigm, an ontology defines a high-level global schema of (already existing) data sources and provides a vocabulary for user queries. An OBDA system rewrites such queries and ontologies into the vocabulary of the data sources and then delegates the actual query evaluation to a suitable query answering system such as a relational database management system or a datalog engine. In this chapter, we mainly focus on OBDA with the ontology language OWL 2QL, one of the three profiles of the W3C standard Web Ontology Language OWL 2, and relational databases, although other possible languages will also be discussed. We consider different types of conjunctive query rewriting and their succinctness, different architectures of OBDA systems, and give an overview of the OBDA system Ontop

Answering SPARQL queries over databases under OWL 2 QL entailment regime

We present an extension of the ontology-based data access platform Ontop that supports answering SPARQL queries under the OWL 2 QL direct semantics entailment regime for data instances stored in relational databases. On the theoretical side, we show how any input SPARQL query, OWL 2 QL ontology and R2RML mappings can be rewritten to an equivalent SQL query solely over the data. On the practical side, we present initial experimental results demonstrating that by applying the Ontop technologies—the tree-witness query rewriting, T-mappings compiling R2RML mappings with ontology hierarchies, and T-mapping optimisations using SQL expressivity and database integrity constraints—the system produces scalable SQL queries

Microscopic self-consistent theory of Josephson junctions including dynamical electron correlations

We formulate a fully self-consistent, microscopic model to study the retardation and correlation effects of the barrier within a Josephson junction. The junction is described by a series of planes, with electronic correlation included through a local self energy for each plane. We calculate current-phase relationships for various junctions, which include non-magnetic impurities in the barrier region, or an interfacial scattering potential. Our results indicate that the linear response of the supercurrent to phase across the barrier region is a good, but not exact indicator of the critical current. Our calculations of the local density of states show the current-carrying Andreev bound states and their energy evolution with the phase difference across the junction. We calculate the figure of merit for a Josephson junction, which is the product of the critical current, Ic, and the normal state resistance, R(N), for junctions with different barrier materials. The normal state resistance is calculated using the Kubo formula, for a system with zero current flow and no superconducting order. Semiclassical calculations would predict that these two quantities are determined by the transmission probabilities of electrons in such a way that the product is constant for a given superconductor at fixed temperature. Our self-consistent solutions for different types of barrier indicate that this is not the case. We suggest some forms of barrier which could increase the Ic.R(N) product, and hence improve the frequency response of a Josephson device.Comment: 46 pages, 21 figure

Substitution in a sense

The Reference Principle (RP) states that co-referring expressions are everywhere intersubstitutable salva congruitate. On first glance, (RP) looks like a truism, but a truism with some bite: (RP) transforms difficult philosophical questions about co-reference into easy grammatical questions about substitutability. This has led a number of philosophers to think that we can use (RP) to make short work of certain longstanding metaphysical debates. For example, it has been suggested that all we need to do to show that the predicate ‘( ) is a horse’ does not refer to a property is point out that ‘( ) is a horse’ and ‘the property of being a horse’ are not everywhere intersubstitutable salva congruitate. However, when we understand ‘substitution’ in the simplest and most straightforward way, (RP) is no truism; in fact, natural languages are full of counterexamples to the principle. In this paper, I introduce a new notion of substitution, and then develop and argue for a version of (RP) that is immune to these counterexamples. Along the way I touch on the following topics: the relation between argument forms and their natural language instances; the reification of sense; the difference between terms and predicates; and the relation between reference and disquotation. I end by arguing that my new version of (RP) cannot be used to settle metaphysical debates quite as easily as some philosophers would like

Sex and the Cinema: What American Pie Teaches the Young

This paper focuses upon the wildly successful blockbuster American Pie teenpics, especially American Pie 3 – the Wedding. I argue that these films, which are sited so securely within the visual and pedagogical machinery of Hollywood culture, are specifically designed to appeal to teenage male audiences, and to provide lessons in sex and romance. Movies like this are especially important as they are experienced by far more teenagers than, for example, instructional films or other classroom materials; indeed, as Henry Giroux has observed, "teens and youth learn how to define themselves outside of the traditional sites of instruction, such as the home and the school… Learning in the postmodern age is located elsewhere – in popular spheres that shape their identities, through forms of knowledge and desires that appear absent from what is taught in schools" (Giroux, 1997, p.49). In this paper I discuss whether the American Pie series is actually a "new age" effort which, via insubordinate performances of gender, contests the hegemonic field of signification which regulates the production of sex, gender and desire, or whether it is more accurately described as a retrogressive hetero-conservative opus with a veneer of sexual radicalism. In short, I intend to probe whether this filmic vector for sex education is all about the shaping of responsible, caring, vulnerable men, or is it guiding them to become just like their heterosexual, middle-class fathers? And whether, despite its riotous and raunchy advertising, American Pie really dishes up something spicy or something terribly wholesome instead

P352 A propensity score-matched, real-world comparison of ustekinumab vs vedolizumab as a second-line treatment for Crohn's disease. The Cross Pennine study II

Abstract Background The best choice of biological agents after failure to an anti-tumour necrosis factor (TNF)α agent in patients with Crohn's disease (CD) is yet to be defined. Real-world data dealing with this issue are still emerging. Methods This is a multicentre retrospective study including eight UK hospitals (August 2014-April 2020). We retrospectively collected data of patients treated with ustekinumab. Clinical response and remission at 14 and 52 weeks evaluated through Physician Global Assessment (PGA) and adverse events were recorded. Predictors of clinical response were examined, and a propensity score-matched analysis with a cohort of patients treated with vedolizumab was performed. Results Overall, 282 patients (mean age 40±15, F:M ratio 1.7:1) treated with ustekinumab were included. Clinical response or remission was reached by 200/282 patients (70.9%) at 14 weeks, and by 162/259 patients (62.5%) at 52 weeks. The most common reason for discontinuation was either primary failure or loss of response, followed by the occurrence of adverse events and by the need for surgery. The rate of non-adherence was rather low (1.4%). Current smoking (OR 2.48, 95% CI 1.13-5.44; p=0.02), baseline PGA (OR 2.4, 95% CI 1.55-3.69, p<0.001), and use of steroids (OR 2.42, 95% CI 1.26-4.65, p=0.008) were associated with 52-week treatment failure. Overall, 74 adverse events occurred, of which 26 were labelled as serious (8.3 per 100 person-year). After exclusion of patients without anti-TNFα exposure prior to starting ustekinumab or vedolizumab and exclusion of patients previously exposed to vedolizumab or ustekinumab, we analysed 275/282 patients (97.5%) from the ustekinumab cohort and 118/135 patients (87.4%) from the vedolizumab cohort. Propensity score analysis revealed that at 14 weeks, patients treated with ustekinumab were 38% (95% CI 25-50%; p<0.001) more likely to achieve a clinical remission, while at 52 weeks, the difference of 9% (95% CI -15-33%; p=0.462) was not significant. Conclusion Ustekinumab was effective and well tolerated in this real-world cohort. While ustekinumab proved more effective at 14-week follow-up, we found no statistically significant differences in outcomes at 52 weeks

Information-seeking behavior of catalog users

This study is based on the data from a survey of catalog use at three university libraries and one public library. Both "known-item" searches and "subject" searches were analyzed. The characteristics of the user population were examined and methodological problems of the survey were discussed. A relation was found between the academic rank of the catalog users and type of search that they carry out. Some of the factors influencing the success or failure of the search were analyzed, and the meaning of "success" for the two types of search was discussed. The study investigated trends in search strategies as well as degree of perseverance of catalog searchers. Implications for the design of modern information retrieval systems were pointed out.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32647/1/0000010.pd

Collective decision making and social interaction rules in mixed-species flocks of songbirds

Associations in mixed-species foraging groups are common in animals, yet have rarely been explored in the context of collective behaviour. Despite many investigations into the social and ecological conditions under which individuals should form groups, we still know little about the specific behavioural rules that individuals adopt in these contexts, or whether these can be generalized to heterospecifics. Here, we studied collective behaviour in flocks in a community of five species of woodland passerine birds. We adopted an automated data collection protocol, involving visits by RFID-tagged birds to feeding stations equipped with antennae, over two winters, recording 91 576 feeding events by 1904 individuals. We demonstrated highly synchronized feeding behaviour within patches, with birds moving towards areas of the patch with the largest proportion of the flock. Using a model of collective decision making, we then explored the underlying decision rule birds may be using when foraging in mixed-species flocks. The model tested whether birds used a different decision rule for conspecifics and heterospecifics, and whether the rules used by individuals of different species varied. We found that species differed in their response to the distribution of conspecifics and heterospecifics across foraging patches. However, simulating decisions using the different rules, which reproduced our data well, suggested that the outcome of using different decision rules by each species resulted in qualitatively similar overall patterns of movement. It is possible that the decision rules each species uses may be adjusted to variation in mean species abundance in order for individuals to maintain the same overall flock-level response. This is likely to be important for maintaining coordinated behaviour across species, and to result in quick and adaptive flock responses to food resources that are patchily distributed in space and time