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The coordinated regulation of mitochondrial and nuclear activities is essential for cellular respiration and its disruption leads to mitochondrial dysfunction, a hallmark of ageing. Mitochondria communicate with nuclei via retrograde signalling pathways that modulate nuclear gene expression in order to maintain mitochondrial homeostasis. The monooxygenase CLK-1 was previously reported to be mitochondrial, with a role in respiration and longevity. We have uncovered a distinct nuclear form of CLK-1 that independently regulates lifespan. Nuclear CLK-1 mediates a retrograde signalling pathway that is conserved from Caenorhabditis elegans to humans and is responsive to mitochondrial reactive oxygen species, thus acting as a barometer of oxidative metabolism. We show that, through modulation of gene expression, the pathway regulates both mitochondrial reactive oxygen species metabolism and the mitochondrial unfolded protein response. Our results demonstrate that a respiratory enzyme acts in the nucleus to control mitochondrial stress responses and longevity.

A multilayer feed-forward neural network, trained with a gradient descent, back-propagation algorithm, is used to estimate the favourability for gold deposits using a raster GIS database for the Tenterfield 1:100 000 sheet area, New South Wales. The database consists of solid geology, regional faults, airborne magnetic and gamma-ray survey data (U, Th, K and total count channels), and 63 deposit and occurrence locations. Input to the neural network consists of feature vectors formed by combining the values from co-registered grid cells in each GIS thematic layer. The network was trained using binary target values to indicate the presence or absence of deposits. Although the neural network was trained as a binary classifier, output values for the trained network are in the range [0.1, 0.9] and are interpreted to indicate the degree of similarity of each input vector to a composite of all the deposit vectors used in training. These values are rescaled to produce a multiclass prospectivity map. To validate and assess the effectiveness of the neural-network method, mineral-prospectivity maps are also prepared using the empirical weights of evidence and the conceptual fuzzy-logic methods. The neural-network method produces a geologically plausible mineral-prospectivity map similar, but superior, to the fuzzy logic and weights of evidence maps. The results of this study indicate that the use of neural networks for the integration of large multisource datasets used in regional mineral exploration, and for prediction of mineral prospectivity, offers several advantages over existing methods. These include the ability of neural networks to: (i) respond to critical combinations of parameters rather than increase the estimated prospectivity in response to each individual favourable parameter; (ii) combine datasets without the loss of information inherent in existing methods; and (iii) produce results that are relatively unaffected by redundant data, spurious data and data containing multiple populations. Statistical measures of map quality indicate that the neural-network method performs as well as, or better than, existing methods while using approximately one-third less data than the weights of evidence method.KEY WORDS: fuzzy logic, GIS, mineral exploration, neural networks, weights of evidence. 764W. M. Brown et al. Figure 6 Prospectivity maps for the Tenterfield 1:100 000 area. (a) Weights of evidence method. (b) Fuzzy-logic method. (c) Neural network method. x, primary gold deposits and occurrences; ᭹, alluvial gold deposits and occurrences; ᮀ, undifferentiated gold deposits and occurrences.

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The Barrow and Dampier Sub-basins of the Northern Carnarvon Basin developed by repeated reactivation of long-lived basement structures during Palaeozoic and Mesozoic tectonism. Inherited basement fabric specific to the terranes and mobile belts in the region comprise northwest, northeast, and north–south-trending Archaean and Proterozoic structures. Reactivation of these structures controlled the shape of the sub-basin depocentres and basement topography, and determined the orientation and style of structures in the sediments.The Lewis Trough is localised over a reactivated NEtrending former strike-slip zone, the North West Shelf (NWS) Megashear. The inboard Dampier Sub-basin reflects the influence of the fabric of the underlying Pilbara Craton. Proterozoic mobile belts underlie the Barrow Sub-basin where basement fabric is dominated by two structural trends, NE-trending Megashear structures offset sinistrally by NS-trending Pinjarra structures.The present-day geometry and basement topography of the basins is the result of accumulated deformation produced by three main tectonic phases. Regional NESW extension in the Devonian produced sinistral strikeslip on NE-trending Megashear structures. Large Devonian-Carboniferous pull-apart basins were introduced in the Barrow Sub-basin where Megashear structures stepped to the left and are responsible for the major structural differences between the Barrow and Dampier Sub-basins. Northwest extension in the Late Carboniferous to Early Permian marks the main extensional phase with extreme crustal attenuation. The majority of the Northern Carnarvon basin sediments were deposited during this extensional basin phase and the subsequent Triassic sag phase. Jurassic extension reactivated Permian faults during renewed NW extension. A change in extension direction occurred prior to Cretaceous sea floor spreading, manifest in basement block rotation concentrated in the Tithonian. This event changed the shape and size of basin compartments and altered fluid migration pathways.The currently mapped structural trends, compartment size and shape of the Barrow and Dampier Sub-basins of the Northern Carnarvon Basin reflect the “character” of the basement beneath and surrounding each of the subbasins.Basement character is defined by the composition, lithology, structure, grain, fabric, rheology and regolith of each basement terrane beneath or surrounding the target basins. Basement character can be discriminated and mapped with mineral exploration methods that use non-seismic data such as gravity, magnetics and bathymetry, and then calibrated with available seismic and well datasets. A range of remote sensing and geophysical datasets were systematically calibrated, integrated and interpreted starting at a scale of about 1:1.5 million (covering much of Western Australia) and progressing to scales of about 1:250,000 in the sub-basins. The interpretation produced a new view of the basement geology of the region and its influence on basin architecture and fill history. The bottom-up or basement-first interpretation process complements the more traditional top-down seismic and well-driven exploration methods, providing a consistent map-based regional structural model that constrains structural interpretation of seismic data.The combination of non-seismic and seismic data provides a powerful tool for mapping basement architecture (SEEBASE™: Structurally Enhanced view of Economic Basement); basement-involved faults (trap type and size); intra-sedimentary geology (igneous bodies, basement-detached faults, basin floor fans); primary fluid focussing and migration pathways and paleo-river drainage patterns, sediment composition and lithology.

The Los Angeles Zoo has maintained and managed six different species of forest duikers since 1975. Over the years we have achieved relative success with the majority of these species. The maintenance and breeding of duikers has proved to be difficult at best. The major problems that we have experienced concern diet, stress-related medical conditions, neonatal mortality, and postanesthetic pneumonia. As concentrate selectors, duikers have a diet relatively low in fiber, a well-developed ability to forage selectively, a rumen bypass that is functionally important, a rapid passage and high fermentation rate for starch, and frequently encountered toxins. From an examination of the captive diet of duikers it is evident that the domestic fruits fed to duikers in captivity are not well suited for them. Duikers are highly susceptible to the slightest amount of stress. The group size in which duikers are managed has proved to be critical in the successful management of these species. In our earlier years of duiker management we often kept five or more animals together in a single exhibit. This would at times result in stress-related jaw abscesses. Our group size has since been reduced to no more than three animals in any one exhibit. Since 1977, the Los Angeles Zoo has had 92 duiker births. The survival rate past 6 months of age has been 61%. Of the 36 neonatal deaths, 42% were stillborn or died within a few hours of birth. Hypothermia and maternal neglect have been linked to infant mortality. Duikers are also easily prone to capture myopathy and regurgitation during anesthesia or capture, which can often lead to aspiration pneumonia. If at all possible, the capture and restraint of a duiker should be avoided. However, there are times when the capture or restraint (chemically or manually) of a duiker is required.

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