21 research outputs found
Scale in object and process ontologies
Scale is of great importance to the analysis of real world
phenomena, be they enduring objects or perduring processes. This paper
presents a new perspective on the concept of scale by considering it within two
complementary ontological views. The first, called SNAP, recognizes enduring
entities or objects, the other, called SPAN, perduring entities or processes.
Within the meta-theory provided by the complementary SNAP and SPAN
ontologies, we apply different theories of formal ontology such as mereology
and granular partitions, and ideas derived from hierarchy theory. These
theories are applied to objects and processes and form the framework within
which we present tentative definitions of scale, which are found to differ
between the two ontologies
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
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Mixed Waste Management Facility closure at the Savannah River Site
The Mixed Waste Management Facility of the Savannah River Plant received hazardous and solid low level radioactive wastes from 1972 until 1986. Because this facility did not have a permit to receive hazardous wastes, a Resource Conservation and Recovery Act closure was performed between 1987 and 1990. This closure consisted of dynamic compaction of the waste trenches and placement of a 3-foot clay cap, a 2-foot soil cover, and a vegetative layer. Operations of the waste disposal facility, tests performed to complete the closure design, and the construction of the closure cap are discussed herein
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The Mixed Waste Management Facility closure and expansion at the Savannah River Site
Process wastes containing radioactive and hazardous constituents have been generated throughout the operational history of the Savannah River Site. Solid wastes containing low level radionuclides were buried in Low Level Radioactive Disposal Facility (LLRWDF). Until 1986, waste containing lead and cadmium was disposed of in the Mixed Waste Management Facility (MWMF) portion of LLRWDF. Between 1986 and 1990, waste containing F-listed hazardous rags were buried. Current Resource Conservation and Recovery Act (RCRA) regulations prohibit the disposal of these hazardous wastes at nonpermitted facilities. This paper describes the closure activities for the MWMF, completed in 1990 and plans proposed for the expansion of this closure to include the LLRWDF suspect solvent rag trenches
Ecological implications of removing a concrete gas platform in the North Sea
Artificial structures such as offshore oil and gas platforms can significantly alter local species communities. It has been argued that this effect should be considered during decisions over their removal during decommissioning. In the North Sea, leaving such structures in place is prohibited but derogations are allowed for large concrete installations. To assess removal options for one such installation, the Halfweg GBS (gravity-based structure) a concrete platform foundation off the Dutch coast, we studied the resident fouling macrofauna community. The faunal structure, biomass and trophic composition of the Halfweg was then compared with those from the surrounding seabed sediments, other local artificial structures and a natural rocky reef. In total, 65 macrofaunal species were observed on the concrete (52 species), steel legs (32) and surrounding rock dump (44) of Halfweg. Mean Simpson diversity per sample was highest on the rock dump (0.71) but concrete (0.54) and steel (0.60) of the GBS were lower than seabed (0.69). Ten of the species observed on the concrete were not reported on other substrates while 10 of the species were also observed in the surrounding seabed. The GBS structure was numerically dominated by Arthropoda which comprised 98% of the total abundance. Mean ash free dry weight (AFDW) was significantly higher (p < 0.001) on the Halfweg substrates (204 g AFDW per m2) than in the surrounding seabed (65 g AFDW per m2). Over 94% of the biomass on Halfweg consisted of the plumose anemone Metridium senile. While common on other reefs, this species was absent from the surrounding seabed. Macrofaunal feeding mechanisms of the concrete and rock dump communities on the GBS were similar to those of nearby sediments, although these differed from those on the Halfweg steel legs. Therefore, the presence of Halfweg alters the local community feeding modes. Multivariate analysis revealed that taxonomic structure of the GBS and other artificial structures significantly differed from that of the sedimentary habitats. Low numbers of non-indigenous species on Halfweg indicated that the structure does not act as a stepping stone for species invasions. Our data show that the Halfweg structures significantly increase local biodiversity and biomass. Removal of the concrete and steel legs of the GBS (leaving the rock dump) will significantly reduce local macrofauna biodiversity. The long-term impact on macrofaunal biomass is low. Leaving the complete Halfweg structure in place will result in an enriched local macrofaunal biodiversity and feeding mode diversity