Legacy and Emerging Persistent Organic Pollutants in Antarctic Benthic Invertebrates near Rothera Point, Western Antarctic Peninsula

The levels of pollutants in polar regions is gaining progressively more attention from the science community. This is especially so for pollutants that persist in the environment and can reach polar latitudes via a wide range of routes, such as persistent organic pollutants (POPs). In this study samples of Antarctic marine benthic organisms were analysed for legacy and emerging POPs to comprehensively assess the current POPs concentrations in Antarctic benthos and infer the potential sources of the pollutants. Specimens of 5 different benthic invertebrate species were collected in 2 distinct locations near the Rothera Research station (67°35'8"S and 68°7'59"W). Any impact of the nearby Rothera Station as a local source of pollution appeared to be negligible. The most abundant chemicals detected were HCB and BDE-209, reaching the highest concentrations in limpets and urchins, followed by sea stars, ascidians and sea cucumbers. The relative congener patterns of PCBs and PBDEs were almost the same in all species. Some chemicals (e.g. Heptachlor, Oxychlordane and Mirex) were detected in the Antarctic invertebrates for the first time. Statistical methods revealed that the distribution of the POPs is not only driven by the feeding traits of the species, but also by the physico-chemical properties of the individual compounds. Benthic invertebrates are excellent indicators of the contaminant patterns of inshore Antarctic ecosystems

Combining machine learning and semantic web: A systematic mapping study

In line with the general trend in artificial intelligence research to create intelligent systems that combine learning and symbolic components, a new sub-area has emerged that focuses on combining Machine Learning components with techniques developed by the Semantic Web community - Semantic Web Machine Learning (SWeML). Due to its rapid growth and impact on several communities in thepast two decades, there is a need to better understand the space of these SWeML Systems, their characteristics, and trends. Yet, surveys that adopt principled and unbiased approaches are missing. To fill this gap, we performed a systematic study and analyzed nearly 500 papers published in the past decade in this area, where we focused on evaluating architectural and application-specific features. Our analysis identified a rapidly growing interest in SWeML Systems, with a high impact on several application domains and tasks. Catalysts for this rapid growth are the increased application of deep learning and knowledge graph technologies. By leveraging the in-depth understanding of this area acquired through this study, a further key contribution of this article is a classification system for SWeML Systems that we publish as ontology.</p

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements