The Muon G-2 Storage Ring Magnet

The muon g-2 experiment at Brookhaven National Laboratory has constructed a 7.112m radius superconducting magnet. The design and construction of the storage ring magnet are described

The invasive coral Oculina patagonica has not been recently introduced to the Mediterranean from the western Atlantic

BACKGROUND: Effective policies, management, and scientific research programs depend on the correct identification of invasive species as being either native or introduced. However, many species continue to be misidentified. Oculina patagonica, first recorded in the Mediterranean Sea in 1966, is believed to have been introduced in anthropogenic times and expanding in a west to east direction. However, its present identification and status as a recently introduced species remain to be explored. In this study, we used multi-locus genetic data to test whether O. patagonica in the Mediterranean has been recently introduced from the western North Atlantic. RESULTS: We found no genetic or historical demographic evidence to support a recent introduction of O. patagonica from the western North Atlantic or an expansion across the Mediterranean. Instead, Mediterranean and Atlantic populations are genetically distinct and appear to have begun diverging about 5 Mya. We also found evidence of a fossil record of Oculina spp. existing in the eastern North Atlantic millions of years before the present. CONCLUSIONS: Our results suggest that Mediterranean populations of O. patagonica have long been isolated from the western Atlantic, either in undetectable numbers or overlooked and undersampled sites and habitats, and have only recently been expanding to invasive levels as a result of environmental changes. Accurate identification of species’ invasive statuses will enable more effective research programs aimed at better understanding the mechanisms promoting the invasive nature of species, which can then lead to the implementation of efficient management plans. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12862-015-0356-7) contains supplementary material, which is available to authorized users

The Brookhaven muon storage ring magnet

The muon g-2 experiment at Brookhaven National Laboratory has the goal of determining the muon anomalous g-value a(mu) ( = (g - 2)/2) to the very high precision of 0.35 parts per million and thus requires a storage ring magnet with great stability and homogeniety. A superferric storage ring with a radius of 7.11 m and a magnetic field of 1.45 T has been constructed in which the field quality is largely determined by the iron, and the excitation is provided by superconducting coils operating at a current of 5200 A. The storage ring has been constructed with maximum attention to azimuthal symmetry and to tight mechanical tolerances and with many features to allow obtaining a homogenous magnetic field. The fabrication of the storage ring, its cryogenics and quench protection systems, and its initial testing and operation are described. (C) 2001 Elsevier Science B.V. All rights reserved