Scientific rationale for the D-CIXS X-ray spectrometer on board ESA's SMART-1 mission to the Moon

The D-CIXS X-ray spectrometer on ESA's SMART-1 mission will provide the first global coverage of the lunar surface in X-rays, providing absolute measurements of elemental abundances. The instrument will be able to detect elemental Fe, Mg, Al and Si under normal solar conditions and several other elements during solar flare events. These data will allow for advances in several areas of lunar science, including an improved estimate of the bulk composition of the Moon, detailed observations of the lateral and vertical nature of the crust, chemical observations of the maria, investigations into the lunar regolith, and mapping of potential lunar resources. In combination with information to be obtained by the other instruments on SMART-1 and the data already provided by the Clementine and Lunar Prospector missions, this information will allow for a more detailed look at some of the fundamental questions that remain regarding the origin and evolution of the Moon.     

The invertebrate ecology of the Chalk aquifer in England (UK)

The Chalk is an important water supply aquifer, yet ecosystems within it remain poorly understood. Boreholes (198) in seven areas of England (UK) were sampled to determine the importance of the Chalk aquifer as a habitat, and to improve understanding of how species are distributed. Stygobitic macro-invertebrates were remarkably common, and were recorded in 67 % of boreholes in unconcealed Chalk, although they were not recorded in Chalk that is concealed by low-permeability strata and thus likely to be confined. Most species were found in shallow boreholes (<21 m) and boreholes with deep (>50 m) water tables, indicating that the habitat is vertically extensive. Stygobites were present in more boreholes in southern England than northern England (77 % compared to 38 %). Only two species were found in northern England compared to six in southern England, but overall seven of the eight stygobitic macro-invertebrate species found in England were detected in the Chalk. Two species are common in southern England, but absent from northern England despite the presence of a continuous habitat prior to the Devensian glaciation. This suggests that either they did not survive glaciations in the north where glaciers were more extensive, or dispersal rates are slow and they have never colonised northern England. Subsurface ecosystems comprising aquatic macro-invertebrates and meiofauna, as well as the microbial organisms they interact with, are likely to be widespread in the Chalk aquifer. They represent an important contribution to biodiversity, and may influence biogeochemical cycles and provide other ecosystem services.     

Analytic signals for multivariate data

Hilbert transformation is a standard tool in univariate signal-processing. It leaves the information content unaffected for, apart from a change of sign, the iterated transform reproduces the original data. As we know from Fourier transforms, such alternative representations of the same information, notwithstanding their theoretical equivalence with the data, can assist powerfully with extracting and interpreting that information. Although the extension to multivariate data is not so obvious for Hilbert as for Fourier transforms, Nabighian gave a treatment of the bivariale situation in 1984. Fueter, some 50 years earlier, had worked on an analogous extension problem, seeking to generalize complex function theory. On comparing these two developments we learn that, although Nabighian's transforms fit naturally into Fueter's theory, they are only one among many alternative possibilities. This paper presents a general theory, of higher dimensional Hilbert transforms and analytic signals, applicable to data of all dimensions less than eight. The change-of-field-direction fillers used in geophysical data processing are shown to arise as special situations.     

True ‘gravitational lens’ effect for cylindrical deflectors

We show that gravitational light deflection is truly equivalent to the optical effect of a prism and a thin diverging lens when the massive deflector has cylindrical symmetry. We then investigate the possibility of cosmological measurements analogous to those proposed by Refsdal in the spherically-symmetric case.This work was partially supported by FINEP, CNPq, and CAPES.     

Monochromatic observations of three nebular objects in the direction of NGC 1714

Using a CCD as detector, we have observed three nebulosities not yet listed in catalogues; they all present a planetary nebula morphology and are situated in the immediate neighbourhood (less than 3 arc min to the East) of NGC 1714. Observations have been made through interference filters centered on the main emission lines of these objects.The observations were made at the E.S.O. in La Silla (Chile).European Southern Observatory, La Silla, Santrago de Chile.     

Mechanical response of the south flank of kilauea volcano, hawaii, to intrusive events along the rift systems

Increased earthquake activity and compression of the south flank of Kilauea volcano, Hawaii, have been recognized by previous investigators to accompany rift intrusions. We further detail the temporal and spatial changes in earthquake rates and ground strain along the south flank induced by six major rift intrusions which occurred between December 1971 and January 1981. The seismic response of the south flank to individual rift intrusions is immediate; the increased rate of earthquake activity lasts from 1 to 4 weeks. Horizontal strain measurements indicate that compression of the south flank usually accompanies rift intrusions and eruptions. Emplacement of an intrusion at a depth greater than about 4 km, such as the June 1982 southwest rift intrusion, however, results in a slight extension of the subaerial portion of the south flank.Horizontal strain measurements along the south flank are used to locate the January 1983 east-rift intrusion, which resulted in eruptive activity. The intrusion is modeled as a vertical rectangular sheet with constant displacement perpendicular to the plane of the sheet. This model suggests that the intrusive body that compressed the south flank in January 1983 extended from the surface to about 2.4 km depth, and was aligned along a strike of N66°E. The intrusion is approximately 11 km in length, extended beyond the January 1983 eruptive fissures, which are 8 km in length and is contained within the 14-km-long region of shallow rift earthquakes.