An Autonomous Lunar Geophysical Experiment Package (ALGEP) for future space missions

Geophysical observations will provide key information about the inner structure of the planets and satellites and understanding the internal structure is a strong constraint on the bulk composition and thermal evolution of these bodies. Thus, geophysical observations are a key to uncovering the origin and evolution of the Moon. In this article, we propose the development of an autonomous lunar geophysical experiment package, composed of a suite of instruments and a central station with standardized interface, which can be installed on various future lunar missions. By fixing the interface between instruments and the central station, it would be possible to easily configure an appropriate experiment package for different missions. We describe here a series of geophysical instruments that may be included as part of the geophysical package: a seismometer, a magnetometer, a heat flow probe, and a laser reflector. These instruments will provide mechanical, thermal, and geodetic parameters of the Moon that are strongly related to the internal structure. We discuss the functionality required for future geophysical observations of the Moon, including the development of the central station that will be used commonly by different payloads

Assays and screening of alpha contaminated soils using low-resolution alpha spectroscopy of thick soil samples

A new approach to estimating concentrations of alpha-emitting contaminants (e.g. U, Th, Ra, Pu, Am) in soil samples has been evaluated. The Victoreen Alpha Activity Monitor has been designed to empirically assay soil samples using low-resolution alpha spectroscopy, of thick soil samples. Pre-processing of the soil samples is minimal, involving only drying the soils and milling them to reduce inhomoceneities. Several laboratory tests of the instrument have been conducted. It has been shown that the instrument obeys simple counting statistics with measurement reproducibility improving with the inverse square root of the counting time. Using acquisition times of 1 to 24 hours the instrument Generated alpha assays of eighteen reference and field soil samples which were in good agreement with radiochemical analyses. It was observed that the alpha activity due to a 10pCi/g {sup 239}Pu spike added to a clean soil could be very readily distinguished from the 14pCi/g background activity of the soil. In a mock field screening test of 100 Pu-contaminated soils, the instrument demonstrated screening success rates ranging from 70% (at a screening level of 5pCi/g) to greater than 90% (at a screening level of 30pCi/g)

Multiple approaches to assess the safety of artisanal marine food in a tropical estuary

In this study, metal and metalloid concentrations and pathogens were measured in shellfish at different locations in a tropical estuary, including sites impacted by sewage and industry. Oyster, mangrove snails and mud snails did not exceed Australian and New Zealand Food Standards maximum levels for copper, lead or estimated inorganic arsenic at any site although copper concentrations in oysters and mud snails exceeded generally expected levels at some locations. Bacterial community composition in shellfish was species-specific regardless of location and different to the surrounding water and sediment. In the snails Telescopium telescopium, Terebralia palustris and Nerita balteata, some bacterial taxa differed between sites, but not in Saccostrea cucullata oysters. The abundance of potential human pathogens was very low and pathogen abundance or diversity was not associated with site classification, i.e. sewage impact, industry impact and reference

Root distribution and water use in coffee shaded with Tabebuia rosea Bertol. and Simarouba glauca DC. compared to full sun coffee in sub-optimal environmental conditions

International audienceRoot niche differentiation for optimal exploitation of resources was found in an arabica coffee agroforestry system in Nicaragua. Rooting behavior was compared in both unshaded (FS) and shaded (AFS) coffee combined with two previously untested tropical timber species (deciduous Tabebuia rosea Bertol. and evergreen Simarouba glauca DC.). The predominant andisol possesses a compacted soil layer (talpetate). The study was conducted in sub-optimal environmental conditions for coffee cultivation (455 m.a.s.l., annual mean 27 A degrees C, 1300 mm rainfall/year, 6 months dry season) in Nicaragua. Twelve and five trenches 200 cm deep were dug in AFS and FS respectively. Roots per unit area were counted on two perpendicular soil faces. Volumetric water was measured continuously over 2 years by using 45 reflectometers in different soil layers. The talpetate varied greatly in depth, thickness and physical structure. Coffee fine roots were more abundant than tree roots and were concentrated in the shallower strata (0-80 cm) whilst tree roots proliferated more below 100 cm. The S. glauca root system was denser below 100 cm than T. rosea root system. There was no meaningful difference in coffee root counts in FS and under T. rosea, but coffee root counts were higher near S. glauca trees. 2012 and 2014 had mild dry seasons and whole profile soil water content was similar in FS and AFS, but in the 2013 severe dry period volumetric water and water uptake were lower in AFS than in FS. This indicates that the normal advantage of greater soil exploration in AFS was cancelled presumably due to continued water uptake by deep rooting trees whereas the FS still had available water

PCR analysis confirms an expanded symptomatology for Australian grapevine yellows

In the 1994/95 season, unusual, widespread and generalised foliar symptoms, similar to those of Australian grapevine yellows (AGY), occurred in late summer-autumn in many regions of Australia. They were confirmed by the polymerase chain reaction (PCR) assay as being associated with the presence of the phytoplasma of AGY. In contrast, the early-season (i.e. late spring-early summer) symptoms of AGY were less common and generally confined to isolated shoots. Positive PCR assays for phytoplasma (65 out of a total of 90) were obtained only from vines showing AGY-like symptoms while none of the 88 PCR assays for symptomless vines were positive. The disorder of restricted spring growth syndrome, widespread and damaging in spring 1994, occurred in some vines which also later showed AGY-like symptoms in the autumn.R.G. Bonfiglioli, P.A.Magarey and R.H.Symon