Four Lessons in Versatility or How Query Languages Adapt to the Web

Exposing not only human-centered information, but machine-processable data on the Web is one of the commonalities of recent Web trends. It has enabled a new kind of applications and businesses where the data is used in ways not foreseen by the data providers. Yet this exposition has fractured the Web into islands of data, each in different Web formats: Some providers choose XML, others RDF, again others JSON or OWL, for their data, even in similar domains. This fracturing stifles innovation as application builders have to cope not only with one Web stack (e.g., XML technology) but with several ones, each of considerable complexity. With Xcerpt we have developed a rule- and pattern based query language that aims to give shield application builders from much of this complexity: In a single query language XML and RDF data can be accessed, processed, combined, and re-published. Though the need for combined access to XML and RDF data has been recognized in previous work (including the W3C’s GRDDL), our approach differs in four main aspects: (1) We provide a single language (rather than two separate or embedded languages), thus minimizing the conceptual overhead of dealing with disparate data formats. (2) Both the declarative (logic-based) and the operational semantics are unified in that they apply for querying XML and RDF in the same way. (3) We show that the resulting query language can be implemented reusing traditional database technology, if desirable. Nevertheless, we also give a unified evaluation approach based on interval labelings of graphs that is at least as fast as existing approaches for tree-shaped XML data, yet provides linear time and space querying also for many RDF graphs. We believe that Web query languages are the right tool for declarative data access in Web applications and that Xcerpt is a significant step towards a more convenient, yet highly efficient data access in a “Web of Data”

Catalytic Investigations as a Facile Route to N-trifluoroethyl Substituted Compounds

Phosphorus compounds have been traditionally thought of as Lewis donor ligands used in transition metal and organometallic chemistry. However, the versatility of phosphorus to act as a Lewis acid has become increasingly apparent, and the influence of this concept in chemistry has had profound implications in recent catalysis. The Lewis acidity of the fluorophosphonium cations [(C6F5)2PhPF]+ and [(C6F5)3PF]+, and applications of these species in hydrodefluorination, isomerization, and hydrosilylation of alkenes and nitriles were previously reported. Manipulations to this catalyst afforded the dicationic imidazolium-phosphonium salt [(SIMes)PFPh2][B(C6F5)4]2, showing similar Lewis acidity and reactivity. Such systems have investigated the hydrodeoxygenation of aliphatic and aromatic ketones. Herein, studies into the hydrodeoxygenation of amides as a simple and versatile methodology for the preparation of N-trifluoroethyl amines and anilines is presented. Furthermore, subsequent Friedel-Crafts activation of trifluoromethyl substituents was investigated. The implications of such activations towards fully aromatic heterocycles and aromatic hydrocarbons is also discussed.M.Sc

Design and Implementation of a Graphical Interface to XQuery

As the use of XML is rapidly growing, a growing number of users without programming skills will need to query XML data. Although designed to be easily understood by humans, XQuery, the XML standard query language, has the typical syntax of programming languages, which most users dislike. In this paper we describe a graphical language (XQBE) inspired by “Query By Example” (QBE), a popular relational query language used by MS Access. XQBE covers a significant subset of XQuery and is supported by a prototype enabling the formulation of queries on a graphical interface and their translation into XQuery, thus providing non-trivial querying capabilities to a wide spectrum of users. Simple queries are easily represented in XQBE, but many “complex” queries allow as well for an intuitive graphical representation

XQuery by Example

XQuery, the standard query language for XML, is gaining popularity among users with a SQL background; indeed, formulating XQuery and SQL queries requires comparable skills. However, this nucleus of programmers is not vast, and the availability of simpler XQuery “dialects ” could be valuable for establishing its success. With this motivation in mind, we designed XQBE, a visual dialect of XQuery inspired by QBE (Query by Example). QBE was initially proposed as alternative to SQL and has gained popularity as the language supported by MS Access, currently presented to users with a very limited experience of query languages. Coherent with the XML data model, XQBE uses one or more hierarchical structures to denote the input XML documents and one structure to denote the output document. Similar to QBE, structures are annotated to express selection predicates; explicit bindings between these structures visualize the input/output mappings. 1

Catalytic reduction of amides to amines by electrophilic phosphonium cations via FLP hydrosilylation

A catalytic methodology for the conversion of amides to amines is reported. Among the 25 examples, 14 reduce N-trifluoroacetamides to give trifluoroethylamines.</p

Relationship between cerebral ultrasound EEG in the neonatal period and neurological outcome in preterm VLBW

The prognostic value of cerebral ultrasound is well-known since many years whereas the importance of the early EEG in the preterm infants was debated for a long time. The main goal of this paper is to compare the prognostic value of the cerebral ultrasound and the EEG in the first year of life in a group of 81 preterm babies (weighted less than 1500 g) followed for the first year of life. Our results show that both EEG and ultrasound images are strictly associated with the neurologic outcome (with a more significant correlation for the EEG) and that abnormal EEGs and ultrasound showing ischemic lesions, but not haemorragic lesions, have the same prognostic value