Measurement of the nuclear modification factor for inclusive jets in Pb+Pb collisions at √sNN=5.02 TeV with the ATLAS detector

Measurements of the yield and nuclear modification factor, RAA, for inclusive jet production are performed using 0.49nb−1of Pb+Pb data at √sNN=5.02TeVand 25pb−1of pp data at √s=5.02TeVwith the ATLAS detector at the LHC. Jets are reconstructed with the anti-kt algorithm with radius parameter R =0.4and are measured over the transverse momentum range of 40–1000GeVin six rapidity intervals covering |y| <2.8. The magnitude of RAA increases with increasing jet transverse momentum, reaching a value of approximately0.6 at 1TeVin the most central collisions. The magnitude of RAA also increases towards peripheral collisions. The value of RAA is independent of rapidity at low jet transverse momenta, but it is observed to decrease with increasing rapidity at high transverse momenta

Pulley Ridge, Gulf of Mexico, USA

Pulley Ridge is a limestone ridge that extends nearly 300 km along the southwestern Florida shelf in the eastern Gulf of Mexico. The southern terminus of Pulley Ridge supports a mesophotic coral ecosystem (MCE) at depths of 59–105 m and is the deepest known photosynthetic coral reef off the continental United States. The biodiversity consists of 95 species of macroalgae, 92 demosponges, 18 octocorals, 17 scleractinian corals, 9 antipatharian corals, and 86 fishes. Twenty managed fishery species occur at Pulley Ridge including red grouper, and since 2010 the lionfish population has dramatically increased. The dominant scleractinian corals are plate like corals of the family Agariciidae (Agaricia spp. and Helioseris cucullata), Montastraea cavernosa, Madracis spp., and Oculina diffusa. The percent cover of benthic biota averaged 49.9% over all regions of Pulley Ridge, and macroalgae were dominant (46.5% cover). Scleractinian corals averaged 1.5% cover and sponges had 1.2% cover. In the past 10 years, the Pulley Ridge MCE had a substantial loss of scleractinian coral. The percent coral cover on the Main Ridge dropped from 12.8% in 2003 to 0.9% by 2012–2015, a 93% loss of coral. However, recent surveys show the majority of corals to be relatively healthy; only 1.21% of the colonies counted (38,368) showed signs consistent with “white syndromes” disease. The prevalence of disease on Pulley Ridge is relatively low compared to the Caribbean. The factors causing the decline of the coral communities at Pulley Ridge between 2003 and 2012 are unknown

Unprecedented Disease-Related Coral Mortality in Southeastern Florida

Anomalously high water temperatures, associated with climate change, are increasing the global prevalence of coral bleaching, coral diseases, and coral-mortality events. Coral bleaching and disease outbreaks are often inter-related phenomena, since many coral diseases are a consequence of opportunistic pathogens that further compromise thermally stressed colonies. Yet, most coral diseases have low prevalence (<5%), and are not considered contagious. By contrast, we document the impact of an extremely high-prevalence outbreak (61%) of white-plague disease at 14 sites off southeastern Florida. White-plague disease was observed near Virginia Key, Florida, in September 2014, and after 12 months had spread 100 km north and 30 km south. The disease outbreak directly followed a high temperature coral-bleaching event and affected at least 13 coral species. Eusmilia fastigiata, Meandrina meandrites, and Dichocoenia stokesi were the most heavily impacted coral species, and were reduced to <3% of their initial population densities. A number of other coral species, including Colpophyllia natans, Pseudodiploria strigosa, Diploria labyrinthiformis, and Orbicella annularis were reduced to <25% of their initial densities. The high prevalence of disease, the number of susceptible species, and the high mortality of corals affected suggests this disease outbreak is arguably one of the most lethal ever recorded on a contemporary coral reef

Performance of the ATLAS detector using first collision data

More than half a million minimum-bias events of LHC collision data were collected by the ATLAS experiment in December 2009 at centre-of-mass energies of 0.9 TeV and 2.36 TeV. This paper reports on studies of the initial performance of the ATLAS detector from these data. Comparisons between data and Monte Carlo predictions are shown for distributions of several track- and calorimeter-based quantities. The good performance of the ATLAS detector in these first data gives confidence for successful running at higher energies