1,573 research outputs found
Efficient Query Processing for SPARQL Federations with Replicated Fragments
Low reliability and availability of public SPARQL endpoints prevent
real-world applications from exploiting all the potential of these querying
infras-tructures. Fragmenting data on servers can improve data availability but
degrades performance. Replicating fragments can offer new tradeoff between
performance and availability. We propose FEDRA, a framework for querying Linked
Data that takes advantage of client-side data replication, and performs a
source selection algorithm that aims to reduce the number of selected public
SPARQL endpoints, execution time, and intermediate results. FEDRA has been
implemented on the state-of-the-art query engines ANAPSID and FedX, and
empirically evaluated on a variety of real-world datasets
Recommended from our members
The Influence of Digital Self-Services on Patient’s Experience In a Polyclinic Context: A Framework Construction
The healthcare sector has done significant investments in technology in order to improve their processes; however there is evidence showing that new technology is not optimally used in certain healthcare settings. In this paper we present a framework to analyse how digital self- service (DSS) can optimize processes and improve patient experience in a polyclinic context. The framework consists of five digital self-service types and seven patient\u27s experience factors, both taken from literature and validated for experts. The framework aims to show the influence of DSS in patient’s experience. The results show a positive impact of self-service diagnosis, treatment and monitoring on the patient`s experience, as well as the positive impact of all the DSS in the patient`s experience factor “Information”. The framework also provides new ideas for further research. In general, this framework can be used by polyclinics and other healthcare institutions to 1) investigate possibilities to optimize processes and 2) identify, which DSS have positive impact on patient\u27s experience
Fedra: Query Processing for SPARQL Federations with Divergence
Data replication and deployment of local SPARQL endpoints improve scalability and availability of public SPARQL endpoints, making the consumption of Linked Data a reality. This solution requires synchronization and specific query processing strategies to take advantage of replication. However, existing replication aware techniques in federations of SPARQL endpoints do not consider data dynamicity. We propose Fedra, an approach for querying federations of endpoints that benefits from replication. Participants in Fedra federations can copy fragments of data from several datasets, and describe them using provenance and views. These descriptions enable Fedra to reduce the number of selected endpoints while satisfying user divergence requirements. Experiments on real-world datasets suggest savings of up to three orders of magnitude
Structure-dependent electrical properties of graphene nanoribbon devices with graphene electrodes
Graphene nanoribbons (GNRs) are a novel and intriguing class of materials in
the field of nanoelectronics, since their properties, solely defined by their
width and edge type, are controllable with high precision directly from
synthesis. Here we study the correlation between the GNR structure and the
corresponding device electrical properties. We investigated a series of field
effect devices consisting of a film of armchair GNRs with different structures
(namely width and/or length) as the transistor channel, contacted with narrowly
spaced graphene sheets as the source-drain electrodes. By analyzing several
tens of junctions for each individual GNR type, we observe that the values of
the output current display a width-dependent behavior, indicating electronic
bandgaps in good agreement with the predicted theoretical values. These results
provide insights into the link between the ribbon structure and the device
properties, which are fundamental for the development of GNR-based electronics.Comment: Published in Carbon (2019
SemLAV: Querying Deep Web and Linked Open Data with SPARQL
International audienceSemLAV allows to execute SPARQL queries against the Deep Web and Linked Open Data data sources. It implements the mediator-wrapper architecture based on view definitions over remote data sources. SPARQL queries are expressed using a mediator schema vocabulary, and SemLAV selects relevant data sources and rank them. The ranking strat-egy is designed to deliver results quickly based only on view definitions, i.e., no statistics, nor probing on sources are required. In this demonstra-tion, we validate the effectiveness of SemLAV approach with real data sources from social networks and Linked Open Data. We show in differ-ent setups that materializing only a subset of ranked relevant views is enough to deliver significant part of expected results
The Grizzly, September 26, 2019
Ursinus Welcomes a New Assistant Director • College Expands Recycling Capacity • Celebrating Ursinus\u27 150th Birthday • U-Imagine Starts Business Workshops • UCARE Offers Voter Registration • Opinions: How Studying Abroad has Been Rewarding; Sesquicentennial Fatigue is Soon to Set In • Stout Defense Stands Tall for Women\u27s Soccer • Men\u27s Soccer off to a Promising Starthttps://digitalcommons.ursinus.edu/grizzlynews/1589/thumbnail.jp
Supported Vanadium Oxide Catalysts: Quantitative Spectroscopy, Preferential Adsorption of V^4+/5+, and Al2O3 Coating of Zeolite Y
A series of supported vanadium oxide catalysts were prepared by the incipient wetness method as a function
of the support composition (Al2O3, SiO2, and USY), the metal oxide loading (0-1 wt %), and the impregnation
salt (vanadyl sulfate and ammonium vanadate). These catalysts have been studied by combined DRS-ESR
spectroscopies in order to quantify the amount of V^4+ and V^5+ and to unravel their coordination geometries.
These spectroscopic fingerprints have been used to study the preferential adsorption of V^4+/5+ ions on SiO2,
Al2O3, and USY. Both V^4+ and V^5+ were preferentially adsorbed on Al2O3 and showed a much smaller pref-erence
for USY and SiO2. The observed preference orders are discussed in relation with the properties of the
support. In addition, a novel method is proposed to coat the external surface of USY with a thin film of
Al2O3. The method is based on the deposition of USY with the so-called Keggin ion, [Al13O4(OH)24(H2O)12]7+ ,
which is too big to enter the USY channels or pores. The obtained Al2O3/USY material showed a preferential
adsorption of V^4+ onto the Al2O3 film, suggesting that this method could be useful for vanadium passivation
of FCC catalysts
Hypericum perforatum L.-Mediated Green Synthesis of Silver Nanoparticles Exhibiting Antioxidant and Anticancer Activities
This contribution focuses on the green synthesis of silver nanoparticles (AgNPs) with a size < 100 nm for potential medical applications by using silver nitrate solution and Hypericum Perforatum L. (St John’s wort) aqueous extracts. Various synthesis methods were used and compared with regard to their yield and quality of obtained AgNPs. Monodisperse spherical nanoparticles were generated with a size of approximately 20 to 50 nm as elucidated by different techniques (SEM, TEM). XRD measurements showed that metallic silver was formed and the particles possess a face-centered cubic structure (fcc). SEM images and FTIR spectra revealed that the AgNPs are covered by a protective surface layer composed of organic components originating from the plant extract. Ultraviolet-visible spectroscopy, dynamic light scattering, and zeta potential were also measured for biologically synthesized AgNPs. A potential mechanism of reducing silver ions to silver metal and protecting it in the nanoscale form has been proposed based on the obtained results. Moreover, the AgNPs prepared in the present study have been shown to exhibit a high antioxidant activity for 2, 2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation, and super oxide anion radical and 2,2-diphenyl-1-picrylhydrazyl. Synthesized AgNPs showed high cytotoxicity by inhibiting cell viability for Hela, Hep G2, and A549 cells
Expanding the Benefits of Tnt1 for the Identification of Dominant Mutations in Polyploid Crops: A Single Allelic Mutation in the MsNAC39 Gene Produces Multifoliated Alfalfa
Most major crops are polyploid species and the production of genetically engineered cultivars normally requires the introgression of transgenic or gene-edited traits into elite germplasm. Thus, a main goal of plant research is the search of systems to identify dominant mutations. In this article, we show that the Tnt1 element can be used to identify dominant mutations in allogamous tetraploid cultivated alfalfa. Specifically, we show that a single allelic mutation in the MsNAC39 gene produces multifoliate leaves (mfl) alfalfa plants, a pivot trait of breeding programs of this forage species. Finally, we discuss the potential application of a combination of preliminary screening of beneficial dominant mutants using Tnt1 mutant libraries and genome editing via the CRISPR/Cas9 system to identify target genes and to rapidly improve both autogamous and allogamous polyploid crops.Fil: Jozefkowicz, Cintia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Gómez, Cristina. Agencia de Extension Rural Villa Maria (aer Villa Maria) ; Estacion Experimental Agropecuaria Manfredi ; Centro Regional Cordoba ; Instituto Nacional de Tecnologia Agropecuaria;Fil: Odorizzi, Ariel Sebastian. Agencia de Extension Rural Villa Maria (aer Villa Maria) ; Estacion Experimental Agropecuaria Manfredi ; Centro Regional Cordoba ; Instituto Nacional de Tecnologia Agropecuaria;Fil: Iantcheva, Anelia. AgroBioInstitute Agricultural Academy; BulgariaFil: Ratet, Pascal. Université D'evry Val D'essonne; Francia. Centre National de la Recherche Scientifique; FranciaFil: Ayub, Nicolás. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; ArgentinaFil: Soto, Gabriela Cynthia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; Argentin
Edge Disorder in Bottom-Up Zigzag Graphene Nanoribbons: Implications for Magnetism and Quantum Electronic Transport
We unveil the nature of the structural disorder in bottom-up zigzag graphene
nanoribbons along with its effect on the magnetism and electronic transport on
the basis of scanning probe microscopies and first-principles calculations. We
find that edge-missing m-xylene units emerging during the cyclodehydrogenation
step of the on-surface synthesis are the most common point defects. These
"bite'' defects act as spin-1 paramagnetic centers, severely disrupt the
conductance spectrum around the band extrema, and give rise to spin-polarized
charge transport. We further show that the electronic conductance across
graphene nanoribbons is more sensitive to "bite" defects forming at the zigzag
edges than at the armchair ones. Our work establishes a comprehensive
understanding of the low-energy electronic properties of disordered bottom-up
graphene nanoribbons
- …