357 research outputs found
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
Inferring user goals from sets of independent queries in a multidatabase environment
Loosely coupled data integration among networked sources has become so ubiquitous over the recent years that many of the services and applications used daily are actually not monolithic information systems but rather collections of sources tied together. Instead of building centralized and large data sources (i.e., the Extract- Transform-Load method), many organizations and individuals are opting for a virtual database approach. Especially along with the advent of service-oriented architectures, it has become very easy to leave data in its original source and to instead recruit the service provided by that source as needed. This structure is seen in a variety of scenarios such as hybrid web applications (mash-ups), enterprise information integration models, aggregation services and federated information retrieval systems. Furthermore, individual users are often forced to procure and assemble the information they need from sources distributed across a network. © 2010 Springer-Verlag Berlin Heidelberg
Heritability of facial soft tissue growth in mono- and dizygotic twins at 12 and 17 years of age: A retrospective cohort study
OBJECTIVE
The purpose of this investigation of untreated monozygotic and dizygotic twins was to identify the genetic and environmental components to the facial soft tissue growth.
SETTINGS AND SAMPLE POPULATION
The sample consisted of 52 untreated monozygotic twins (36 male and 16 female) and 46 untreated dizygotic twins (23 male and 23 female) from the Forsyth Moorrees Twin Study (1959-1975).
MATERIALS AND METHODS
Lateral cephalograms were taken at 12 and 17Â years of age and traced to analyse facial convexity, nasolabial angle, upper and lower lip thickness, upper and lower lip profile and nose prominence. The genetic and environmental components of variance were analysed with structural equation modelling for multilevel mixed-effects model.
RESULTS
At 12Â years of age, strong additive genetic influence was seen for facial convexity (70%), upper lip profile (66%) and nose prominence (65%), whereas strong dominant genetic components were found for upper lip thickness (56%). Nevertheless, under unique environment influence were nasolabial angle (58%), lower lip profile (51%) and lower lip thickness (64%). At 17Â years of age, only upper lip thickness (55%) and nose prominence (84%) were under strong additive genetic control, while the rest of the variables were under strong dominant genetic control. The only exception was lower lip thickness (61%), which is still influenced by the unique environment.
CONCLUSION
Although monozygotic/dizygotic twins share at least part of their genome, at both times either additive, dominant or environmental components were found. Nevertheless, at 17Â years of age most of the variables are either under additive or dominant genetic influence
Discordant bioinformatic predictions of antimicrobial resistance from whole-genome sequencing data of bacterial isolates: an inter-laboratory study.
Antimicrobial resistance (AMR) poses a threat to public health. Clinical microbiology laboratories typically rely on culturing bacteria for antimicrobial-susceptibility testing (AST). As the implementation costs and technical barriers fall, whole-genome sequencing (WGS) has emerged as a 'one-stop' test for epidemiological and predictive AST results. Few published comparisons exist for the myriad analytical pipelines used for predicting AMR. To address this, we performed an inter-laboratory study providing sets of participating researchers with identical short-read WGS data from clinical isolates, allowing us to assess the reproducibility of the bioinformatic prediction of AMR between participants, and identify problem cases and factors that lead to discordant results. We produced ten WGS datasets of varying quality from cultured carbapenem-resistant organisms obtained from clinical samples sequenced on either an Illumina NextSeq or HiSeq instrument. Nine participating teams ('participants') were provided these sequence data without any other contextual information. Each participant used their choice of pipeline to determine the species, the presence of resistance-associated genes, and to predict susceptibility or resistance to amikacin, gentamicin, ciprofloxacin and cefotaxime. We found participants predicted different numbers of AMR-associated genes and different gene variants from the same clinical samples. The quality of the sequence data, choice of bioinformatic pipeline and interpretation of the results all contributed to discordance between participants. Although much of the inaccurate gene variant annotation did not affect genotypic resistance predictions, we observed low specificity when compared to phenotypic AST results, but this improved in samples with higher read depths. Had the results been used to predict AST and guide treatment, a different antibiotic would have been recommended for each isolate by at least one participant. These challenges, at the final analytical stage of using WGS to predict AMR, suggest the need for refinements when using this technology in clinical settings. Comprehensive public resistance sequence databases, full recommendations on sequence data quality and standardization in the comparisons between genotype and resistance phenotypes will all play a fundamental role in the successful implementation of AST prediction using WGS in clinical microbiology laboratories
Cephalometric Variability Among Siblings: A Pilot Study
Objective:To determine whether multiple siblings resemble one another in their craniofacial characteristics as measured on cephalometric radiographs.Methods:This study was conducted retrospectively using the Forsyth Moorrees twin sample. A total of 32 families were included, each with ≥4 postpubertal siblings, totaling 142 subjects. Only 1 monozygotic twin was included per family. Headfilms were digitized, skeletal landmarks were located, and 6 parameters that indicated sagittal jaw relationships and vertical status were measured. Diverse statistical approaches were used. Dixon’s Q-test detected outliers in a family for a given parameter. Manhattan Distance quantified similarity among siblings per parameter. Scatter plots visually displayed subject’s measure relative to the mean and standard deviation of each parameter to assess the clinical relevance of the differences.Results:A total of 11 families (34.4%) had no outliers on any parameter, 13 families (40.6%) had outliers on 1 parameter, and 8 families (25%) had outliers on ≥2 parameters. We identified 29 individuals with at least 1 outlying measure (20.4%). Among these, only 2 individuals (1.4%) were significantly different from their siblings for more than 1 measurement. Although the majority of the families did not demonstrate any statistical outlier, the ranges of the measurements were clinically relevant as they might suggest different treatment. For example, the mean range of SNB (Sella-Nasion-B point) angles was 7.23°, and the mean range of MPA was 9.42°.Conclusion:Although families are generally not dissimilar in their craniofacial characteristics, measurements from siblings cannot be used to predict the measurements of another sibling in a clinically meaningful way
Intensional Query Answering to XQuery Expressions
XML is a representation of data which may require huge amounts of storage space and query processing time. Summarized representations of XML data provide succinct information which can be directly queried, either when fast yet approximate answers are sufficient, or when the actual dataset is not available. In this work we show which kinds of XQuery expressions admit a partial answer by using association rules extracted from XML datasets. Such partial information provide intensional answers to queries formulated as XQuery expressions
Growth dynamics and the evolution of cooperation in microbial populations
Microbes providing public goods are widespread in nature despite running the
risk of being exploited by free-riders. However, the precise ecological factors
supporting cooperation are still puzzling. Following recent experiments, we
consider the role of population growth and the repetitive fragmentation of
populations into new colonies mimicking simple microbial life-cycles.
Individual-based modeling reveals that demographic fluctuations, which lead to
a large variance in the composition of colonies, promote cooperation. Biased by
population dynamics these fluctuations result in two qualitatively distinct
regimes of robust cooperation under repetitive fragmentation into groups.
First, if the level of cooperation exceeds a threshold, cooperators will take
over the whole population. Second, cooperators can also emerge from a single
mutant leading to a robust coexistence between cooperators and free-riders. We
find frequency and size of population bottlenecks, and growth dynamics to be
the major ecological factors determining the regimes and thereby the
evolutionary pathway towards cooperation.Comment: 26 pages, 6 figure
Role of the electro-thermo-mechanical multiple coupling on the operation of RF microswitch
A phenomenological approach is proposed to identify some effects occurring within the structure of the microswitch conceived for radio frequency application. This microsystem is operated via a nonlinear electromechanical action imposed by the applied voltage. Unfortunately, it can be affected by residual stress, due to the microfabrication process, therefore axial and flexural behaviors are strongly coupled. This coupling increases the actuation voltage required to achieve the so-called ‘‘pull-in'' condition. Moreover, temperature may strongly affect strain and stress distributions, respectively. Environmental temperature, internal dissipation of material, thermo-elastic and Joule effects play different roles on the microswitch flexural isplacement. Sometimes buckling phenomenon evenly occurs. Literature show that all those issues make difficult an effective computation of ‘‘pull-in'' and ‘‘pull-out'' voltages for evenly distinguishing the origin of some failures detected in operation. Analysis, numerical methods and experiments are applied to an industrial test case to investigate step by step the RF-microswitch operation. Multiple electro-hermomechanical coupling is first modeled to have a preliminary and comprehensive description of the microswitch behavior and of its reliability. ‘‘Pull-in'' and ‘‘pull-out'' tests are then performed to validate the proposed models and to find suitable criteria to design the RF-MEM
- …