The Odyssey Approach for Optimizing Federated SPARQL Queries

Answering queries over a federation of SPARQL endpoints requires combining data from more than one data source. Optimizing queries in such scenarios is particularly challenging not only because of (i) the large variety of possible query execution plans that correctly answer the query but also because (ii) there is only limited access to statistics about schema and instance data of remote sources. To overcome these challenges, most federated query engines rely on heuristics to reduce the space of possible query execution plans or on dynamic programming strategies to produce optimal plans. Nevertheless, these plans may still exhibit a high number of intermediate results or high execution times because of heuristics and inaccurate cost estimations. In this paper, we present Odyssey, an approach that uses statistics that allow for a more accurate cost estimation for federated queries and therefore enables Odyssey to produce better query execution plans. Our experimental results show that Odyssey produces query execution plans that are better in terms of data transfer and execution time than state-of-the-art optimizers. Our experiments using the FedBench benchmark show execution time gains of at least 25 times on average.Comment: 16 pages, 10 figure

Electrodynamics of Black Holes in STU Supergravity

External magnetic fields can probe the composite structure of black holes in string theory. With this motivation we study magnetised four-charge black holes in the STU model, a consistent truncation of maximally supersymmetric supergravity with four types of electromagnetic fields. We employ solution generating techniques to obtain Melvin backgrounds, and black holes in these backgrounds. For an initially electrically charged static black hole immersed in magnetic fields, we calculate the resultant angular momenta and analyse their global structure. Examples are given for which the ergoregion does not extend to infinity. We calculate magnetic moments and gyromagnetic ratios via Larmor's formula. Our results are consistent with earlier special cases. A scaling limit and associated subtracted geometry in a single surviving magnetic field is shown to lift to $AdS_3\times S^2$. Magnetizing magnetically charged black holes give static solutions with conical singularities representing strings or struts holding the black holes against magnetic forces. In some cases it is possible to balance these magnetic forces.Comment: 31 page

Lax pair and Darboux transformation of noncommutative U(N) principal chiral model

We present a noncommutative generalization of Lax formalism of U(N) principal chiral model in terms of a one-parameter family of flat connections. The Lax formalism is further used to derive a set of parametric noncommutative B\"{a}cklund transformation and an infinite set of conserved quantities. From the Lax pair, we derive a noncommutative version of the Darboux transformation of the model.Comment: 1+20 page

Inter-strain cross-fertility tests on cultures from Israel and America in the homothallic fungus, Sordaria fimicola

Inter-strain cross-fertility was studied in relation to geographical origin in a homothallic, self-fertile fungus, by looking for hybrid perithecia in wild-type x ascospore colour mutant crosses. Strains from opposite slopes in \u27Evolution Canyon\u27, Israel, showed no cross-fertility with American or Canadian strains; there was excellent cross-fertility with other strains from the same slope, but an occasional lack of cross-fertility with strains from the other slope

Co-evolution of RDF Datasets

Linking Data initiatives have fostered the publication of large number of RDF datasets in the Linked Open Data (LOD) cloud, as well as the development of query processing infrastructures to access these data in a federated fashion. However, different experimental studies have shown that availability of LOD datasets cannot be always ensured, being RDF data replication required for envisioning reliable federated query frameworks. Albeit enhancing data availability, RDF data replication requires synchronization and conflict resolution when replicas and source datasets are allowed to change data over time, i.e., co-evolution management needs to be provided to ensure consistency. In this paper, we tackle the problem of RDF data co-evolution and devise an approach for conflict resolution during co-evolution of RDF datasets. Our proposed approach is property-oriented and allows for exploiting semantics about RDF properties during co-evolution management. The quality of our approach is empirically evaluated in different scenarios on the DBpedia-live dataset. Experimental results suggest that proposed proposed techniques have a positive impact on the quality of data in source datasets and replicas.Comment: 18 pages, 4 figures, Accepted in ICWE, 201

Why are we failing to implement imaging studies with radiolabelled new molecular entities in early oncology drug development?

In early drug development advanced imaging techniques can help with progressing new molecular entities (NME) to subsequent phases of drug development and thus reduce attrition. However, several organizational, operational, and regulatory hurdles pose a significant barrier, potentially limiting the impact these techniques can have on modern drug development. Positron emission tomography (PET) of radiolabelled NME is arguably the best example of a complex technique with a potential to deliver unique decision-making data in small cohorts of subjects. However, to realise this potential the impediments to timely inclusion of PET into the drug development process must be overcome. In the present paper, we discuss the value of PET imaging with radiolabelled NME during early anticancer drug development, as exemplified with one such NME. We outline the multiple hurdles and propose options on how to streamline the organizational steps for future studies

The experiences of carers looking after people with Parkinson's disease who exhibit impulsive and compulsive behaviours: an exploratory qualitative study

BACKGROUND: Impulsive and compulsive behaviours (ICBs) are a serious complication in Parkinson disease (PD) strongly associated with dopamine replacement therapy used to treat patients. These behaviours comprise abnormal activities such as pathological gambling, binge eating, compulsive shopping, and hypersexuality. These behaviours place a considerable burden on patients and on their carers and families. The aim of this qualitative study is to understand the experiences of carers who were confronted by the development of these behaviours. DESIGN: An exploratory qualitative study. METHODS: Using a convenience sampling approach, 13 carers were recruited to participate in semi-structured interviews. Interviews were conducted over the telephone. Verbatim transcripts were analysed used a thematic analysis approach. COREQ guidelines were adhered to in the reporting of this study. RESULTS: Five main themes were identified: (1) realisation - developing awareness of ICB symptoms and their causes; (2) reacting - confronting and attempts to manage ICBs; (3) reaching out - help-seeking and selective disclosure; (4) reframing - shifting perspectives on ICBs over time; and (5) resignation - impact on relationships and facing the future. CONCLUSIONS: The profound impact of ICBs on quality of life, relationships, and economic stability was clear in the carers' accounts. Possible avenues for future clinical research are suggested. RELEVANCE TO CLINICAL PRACTICE: The potentially devastating effects of ICBs provide a strong imperative for nurses and other health professionals to ensure that close monitoring for symptom development together with patient education are always part of practice

A Study on Effect of Microbial Growth on Dentures in Relation to Denture Storage and Overnight Soaking of Dentures in Various Soaking Solutions -An In Vitro Study

Background: Denture hygiene is essential for preventing microbial growth and associated oral health issues in denture wearers. This in vitro study investigates the effect of denture storage conditions and overnight soaking in various solutions on microbial growth on denture surfaces. Methods: Standardized denture models were inoculated with Candida albicans, Streptococcus mutans, and Staphylococcus aureus and subjected to dry and moist storage conditions. Soaking solutions included commercial denture cleanser, sodium hypochlorite, hydrogen peroxide, and distilled water (control). Microbial assessments were conducted at specified intervals. Results: Moist storage significantly promoted microbial growth on dentures compared to dry storage. Soaking solutions, especially commercial denture cleanser, sodium hypochlorite, and hydrogen peroxide, demonstrated substantial reductions in microbial counts compared to distilled water. Conclusion: Denture storage conditions and choice of soaking solution significantly influence microbial growth on dentures. Moist storage and the use of antimicrobial solutions are effective strategies for reducing microbial colonization. Keywords: Denture hygiene, microbial growth, denture storage, soaking solutions, oral health

Spike sorting for large, dense electrode arrays

Developments in microfabrication technology have enabled the production of neural electrode arrays with hundreds of closely spaced recording sites, and electrodes with thousands of sites are under development. These probes in principle allow the simultaneous recording of very large numbers of neurons. However, use of this technology requires the development of techniques for decoding the spike times of the recorded neurons from the raw data captured from the probes. Here we present a set of tools to solve this problem, implemented in a suite of practical, user-friendly, open-source software. We validate these methods on data from the cortex, hippocampus and thalamus of rat, mouse, macaque and marmoset, demonstrating error rates as low as 5%