The Need for Collaboration Between Ordnance Manufacturers and UXO Clean-up Personnel

The ability to locate unexploded ordnance remotely and accurately increases the safety and efficiency of clearance efforts. To achieve maximum effectiveness, UXO manufacturers and removal groups should coordinate resources and information to create new and practical technologies to assist in efforts to identify failure rates and prevent civilian casualties. The Lost Puppy Proposal is one example of a life-saving technology that could result from such collaboration

Deformation and fluid-rock interaction along then reactivated Outer Hebrides fault zone, Scotland

The Outer Hebrides Fault Zone (OHFZ) is a major, moderately E- to ESE-dipping long-lived reactivated fault zone which is developed in, and cross-cuts, crystalline amphibolite to granulite grade Lewisian basement gneisses, NW Scotland. A complex assemblage of different fault rocks and structures is presently exposed along the OHFZ, which reflects deformation at a range of crustal depths and metamorphic (temperature, pressure, fluid activity) conditions. Detailed field and microstructural observations have demonstrated that segments of the fault zone which display evidence of repeated reactivation over long periods of geological time (movements range from late Laxfordian / Grenvillian to Oligocene in age) are characterised by intense, localised greenschist facies retrogression and the development of sericite- and chlorite-bearing phyllonitic shear zones. In contrast, phyllonite is absent from segments of the fault zone which have not suffered extensive reactivation. These observations are consistent with phyllonitisation at mid-crustal depths having caused profound long-term mechanical weakening of the OHFZ,Two phases of retrogression and phyllonitisation have been recognised along the OHFZ:Upper greenschist facies, Late Laxfordian / Grenvillian phyllonitisation, which occurred at between 15 and 17km depth (Lewis and Harris only), and Lower greenschist facies, Caledonian phyllonitisation, which occurred at between 8 and 9km depth (Lewis, Harris and the Uists).Microstructural and geochemical studies of selected phyllonites from reactivated segments of the OHFZ demonstrate that greenschist facies retrogression and phyllonitisation were promoted by the influx of warm (c.250 to 450 C), hydrous iron^ and magnesium-bearing, oxidising fluids into the fault zone. Fluid flow during upper greenschist facies phyllonitisation was focused into pre-existing bands of highly strained quartzo-feldspathic mylonite, whilst fluid flow during lower greenschist facies phyllonitisation was focused predominantly into pre-existing brittle fractures and cataclastic crush zones. Thus, the distribution and intensity of fluid flow, and hence the distribution and intensity of retrogression and phyllonitisation were ultimately governed by the nature of pre-existing permeability pathways through the fault zone. It is therefore concluded that the long-term rheological evolution of reactivated basement fault zones is inexorably linked to the mid-crustal permeability evolution of such structure

The Consistency of Probabilistic Databases with Independent Cells

A probabilistic database with attribute-level uncertainty consists of relations where cells of some attributes may hold probability distributions rather than deterministic content. Such databases arise, implicitly or explicitly, in the context of noisy operations such as missing data imputation, where we automatically fill in missing values, column prediction, where we predict unknown attributes, and database cleaning (and repairing), where we replace the original values due to detected errors or violation of integrity constraints. We study the computational complexity of problems that regard the selection of cell values in the presence of integrity constraints. More precisely, we focus on functional dependencies and study three problems: (1) deciding whether the constraints can be satisfied by any choice of values, (2) finding a most probable such choice, and (3) calculating the probability of satisfying the constraints. The data complexity of these problems is determined by the combination of the set of functional dependencies and the collection of uncertain attributes. We give full classifications into tractable and intractable complexities for several classes of constraints, including a single dependency, matching constraints, and unary functional dependencies

A mass stranding of squid Martialia hyadesi Rochebrunne & Mabille (Teuthoidea: Ommastrepidae) at Macquarie Island

A large number of squid, subsequently identified as Martialia hyadesi (Ommastrephidae) was stranded on beaches at the northern end of Macquarie Island, 54°30'S, 158°57'E, on 5 March 1971. The squid were immature, or at least pre-breeding, and had been feeding recently. It is suggested that a sudden change in wind direction, coupled with a rising tide, caused the stranding. This is the first reported stranding of this species, which has not previously been recorded in the Pacific region

Palaeoproterozoic orogenic gold style mineralization at the Southwestern Archaean Tanzanian cratonic margin, Lupa Goldfield, SW Tanzania: Implications from U–Pb titanite geochronology

The Lupa Goldfield, situated at the southwestern Tanzanian cratonic margin, comprises a network of auriferous quartz veins and greenschist facies mylonitic shear zones cutting a suite of Archaean–Palaeoproterozoic granitic–gabbroic intrusions. The existing geochronological database points to a protracted, but episodic 1.96–1.88 Ga magmatic history that is broadly coincident with the 2.1–1.8 Ga Ubendian Orogeny. Molybdenite, pyrite and chalcopyrite samples from mineralized quartz veins and mylonitic shear zones yield Re–Os model ages that range from 1.95 to 1.88 Ga, whereas ca. 1.88 Ga pyrite with gold bearing inclusions and sampled from the host mylonitic shear zone suggest that gold occurred relatively late in this hydrothermal history. The ca. 1.88 Ga gold event is recorded at all five of the studied prospects, whereas the relationship between gold and the disparately older 1.95 and 1.94 Ga Re–Os molybdenite ages is unclear. New U–Pb metamorphic titanite dating of a foliated Archaean granite sample (ca. 2.76 Ga) suggests that the onset of ductile deformation within the Lupa Goldfield occurred at ca. 1.92 Ga, and some ca. 40 Myr prior to auriferous and brittle–ductile mylonitic shear zones at ca. 1.88 Ga. Early ductile deformation is not associated with gold mineralization, but the ductile deformation fabrics and, in particular the development of rheologically weak chloritic folia, may have acted as zones of pre-existing weakness that localized strain and influenced the geometry of later auriferous mylonitic shear zones. The large age difference between U–Pb zircon and titanite ages for the Archaean granite sample is in contrast to new U–Pb titanite ages for the Saza Granodiorite (1930 ± 3 Ma), which are only slightly outside of analytical uncertainty at the 2σ level with a previously reported U–Pb zircon age for the same sample (1935 ± 1 Ma). These new age results, together with previously reported U–Pb and Re–Os ages, highlight the protracted magmatic, hydrothermal and structural evolution of the Lupa Goldfield (1.96–1.88 Ga). They are also consistent with other palaeo-convergent margins where orogenic gold style mineralization occurs relatively late in the orogen's tectono-thermal history