Optimizing repair programs for consistent query answering

Databases may not satisfy integrity constraints (ICs) for several reasons. Nevertheless, in most of the cases an important part of the data is still consistent wrt certain desired ICs, and the database can still give some correct answers to queries wrt those ICs. Consistent query answers are characterized as ordinary answers obtained from every minimally repaired and consistent version of the database. Database repairs can be specified as stable models of disjunctive logic programs with program constraints. In this paper, we optimize repair programs, model computation, and query evaluation from them. We make repair programs more compact by eliminating redundant rules and unnecessary programs denial constraints. These results facilitate the application of magic sets techniques to query evaluation in general, and in DLV, a logic programming system that implements the stable models semantics, in particular. We also analyze the implementation in DLV of queries with aggregate functions

Evaluación económica de denosumab en pacientes con tumores sólidos con metástasis óseas en el IMSS

Objetivo: Evaluar económicamente el denosumab en comparación con un escenario mixto de ácido zoledrónico o no tratamiento si existe contraindicación a dicho agente por enfermedad renal grave (Mix AZ/No Trt) en pacientes con tumores sólidos (TS) con metástasis ósea. Método: Análisis de costo-efectividad basado en un modelo Markov, con horizonte temporal de por vida y bajo perspectiva del Instituto Mexicano del Seguro Social. Se evaluaron las frecuencias de eventos relacionados con esqueleto (ERE) y los costos asociados con adquisición de medicamentos, infusión de AZ, manejo de rutina, atención de ERE y tratamiento de eventos adversos serios. Resultados: En el caso base, denosumab resultó dominante sobre Mix AZ/No Trt, con ahorro promedio de $2,494 pesos y 0.781 ERE evitados por paciente. Si AZ se administra cada 12 semanas, denosumab no sería dominante, pero sí costo-efectivo. El denosumab fue dominante o costo-efectivo en 74.7% de las simulaciones. Conclusiones: En pacientes con TS con metástasis ósea, denosumab representa una intervención dominante o al menos costo-efectiva frente al Mix AZ/No Trt

Designing, specifying and querying metadata for virtual data integration systems

We show how to specify and use the metadata for a virtual and relational data integration system under the local-as-view (LAV) approach. We use XML and RuleML for representing metadata, like the global and local schemas, the mappings between the former and the latter, and global integrity constraints. XQuery is used to retrieve relevant information for query planning. The system uses an extended inverse rules algorithm for computing certain answers that is provably correct for monotone relational global queries. For query answering, evaluation engines for answer set programs on relational databases are used. The programs declaratively specify the legal instances of the integration system

Query Rewriting using Datalog for Duplicate Resolution

Matching Dependencies (MDs) are a recent proposal for declarative entity resolution. They are rules that specify, given the similarities satisfied by values in a database, what values should be considered duplicates, and have to be matched. On the basis of a chase-like procedure for MD enforcement, we can obtain clean (duplicate-free) instances; actually possibly several of them. The clean answers to queries (which we call the resolved answers) are invariant under the resulting class of instances. In this paper, we investigate a query rewriting approach to obtaining the resolved answers (for certain classes of queries and MDs). The rewritten queries are specified in stratified Datalog not,s with aggregation. In addition to the rewriting algorithm, we discuss the semantics of the rewritten queries, and how they could be implemented by means of a DBMS

Measuring and computing database inconsistency via repairs

We propose a generic numerical measure of inconsistency of a database with respect to a set of integrity constraints. It is based on an abstract repair semantics. A particular inconsistency measure associated to cardinality-repairs is investigated; and we show that it can be computed via answer-set programs

Millennial-scale sea surface temperature and Patagonian Ice Sheet changes off southernmost Chile (53 degrees S) over the past similar to 60 kyr

Glacial millennial-scale paleoceanographic changes in the Southeast Pacific and the adjacent Southern Ocean are poorly known due to the scarcity of well-dated and high resolution sediment records. Here we present new surface water records from sediment core MD07-3128 recovered at 53 degrees S off the Pacific entrance of the Strait of Magellan. The alkenone-derived sea surface temperature (SST) record reveals a very strong warming of ca. 8 C over the last Termination and substantial millennial-scale variability in the glacial section largely consistent with our planktonic foraminifera oxygen isotope (delta(18)O) record of Neogloboquadrina pachyderma (sin.). The timing and structure of the Termination and some of the millennial-scale SST fluctuations are very similar to those observed in the well-dated SST record from ODP Site 1233 (41 degrees S) and the temperature record from Drowning Maud Land Antarctic ice core supporting the hemispheric-wide Antarctic timing of SST changes. However, differences in our new SST record are also found including a long-term warming trend over Marine Isotope Stage (MIS) 3 followed by a cooling toward the Last Glacial Maximum (LGM). We suggest that these differences reflect regional cooling related to the proximal location of the southern Patagonian Ice Sheet and related meltwater supply at least during the LGM consistent with the fact that no longer SST cooling trend is observed in ODP Site 1233 or any SST Chilean record. This proximal ice sheet location is documented by generally higher contents of ice rafted debris (IRD) and tetra-unsaturated alkenones, and a slight trend toward lighter planktonic delta(18)O during late MIS 3 and MIS 2