Reproductive biology of Mustelus lenticulatus from Kaikoura and Nelson

Mustelus lenticulatus is a non‐placental ovoviviparous shark with a gestation period of about 11 months. Young are born at a total length of 30–32 cm from September to December. Copulation, and ovulation of a further set of eggs, rapidly follows parturition. Fecundity increases with the length of the female; the most eggs found in one female was 24; the mean for all females was 10.73.

Males mature at about 85 cm total length and females at 95 cm at Kaikoura. Nelson males probably mature at a smaller size than do Kaikoura males. Nelson females mature at about 85 cm. Maximum observed lengths were 137 cm for females and 115 cm for males.     

A powder neutron diffraction study of the crystal structure of the fluoroperovskite NaMgF<Subscript>3</Subscript> (neighborite) from 300 to 3.6 K

The cell dimensions and crystal structures of the fluoroperovskite NaMgF₃ (neighborite), synthesized by solid state methods, have been determined by powder neutron diffraction and Rietveld refinement over the temperature range 300–3.6 K using Pt metal as an internal standard for calibration of the neutron wavelength. These data show that Pbnm NaMgF₃ does not undergo any phase transitions to structures of lower symmetry with decreasing temperature. The cell dimensions and atomic coordinates together with polyhedron volumes and distortion indices are given for Pbnm NaMgF₃ at 25 K intervals from 300 to 3.6 K. Decreases in the a and c cell dimensions reach a saturation point at 50 K, whereas the b dimension becomes saturated at 150 K. The distortion of the structure of Pbnm NaMgF₃ from the aristotype cubic structure is described in terms of the tilting of the MgF₆ octahedra according to the tilt scheme a ⁻ a ⁻ c ⁺ . With decreasing temperature the antiphase tilt (a ⁻) increases from 14.24° to 15.39°, whereas the in-phase tilt (c ⁺ ) remains effectively constant at ∼10.7°. Changes in the tilt angles are insufficient to cause changes in the coordination sphere of Na that might induce a low temperature phase transition. The structure of Pbnm NaMgF₃ is also described in terms of normal mode analysis and displacements of the condensed normal modes are compared with those of Pbnm KCaF₃.     

Aerodynamic Parameters of a UK City Derived from Morphological Data

Detailed three-dimensional building data and a morphometric model are used to estimate the aerodynamic roughness length z ₀ and displacement height d over a major UK city (Leeds). Firstly, using an adaptive grid, the city is divided into neighbourhood regions that are each of a relatively consistent geometry throughout. Secondly, for each neighbourhood, a number of geometric parameters are calculated. Finally, these are used as input into a morphometric model that considers the influence of height variability to predict aerodynamic roughness length and displacement height. Predictions are compared with estimations made using standard tables of aerodynamic parameters. The comparison suggests that the accuracy of plan-area-density based tables is likely to be limited, and that height-based tables of aerodynamic parameters may be more accurate for UK cities. The displacement heights in the standard tables are shown to be lower than the current predictions. The importance of geometric details in determining z ₀ and d is then explored. Height variability is observed to greatly increase the predicted values. However, building footprint shape only has a significant influence upon the predictions when height variability is not considered. Finally, we develop simple relations to quantify the influence of height variation upon predicted z ₀ and d via the standard deviation of building heights. The difference in these predictions compared to the more complex approach highlights the importance of considering the specific shape of the building-height distributions. Collectively, these results suggest that to accurately predict aerodynamic parameters of real urban areas, height variability must be considered in detail, but it may be acceptable to make simple assumptions about building layout and footprint shape.     

Dense Gas Diagnostics: Maser Excitation and Variability

I review a number of diagnostic techniques, based upon the excitation and variability of astrophysical masers, which can be applied to dense gas. In each case, I consider the observations necessary and the amount of interpretation, or modelling, required to complete the analysis of a source, presenting examples of each diagnostic method.     

Forecasting off-road trafficability

Forecasting off-road trafficability represents an interesting problem in the earth science field, since variables ranging from solar insolation to soil shear strength are involved. However, existing trafficability models do not include precipitation-soil moisture deterministic submodels. Instead, they frequently commence with soil moisture and invoke empirical relationships to predict trafficability. This investigation couples a deterministic soil moisture submodel to a principal empirical soil moisture-trafficability model. Sensitivity analysis shows the impact cloud cover, as well as other variables, can have on the trafficability of three soil types, and the complexity of the post-storm trafficability response.     

Road-cut slope topography and stability relationships in St Lucia,West Indies

Slope topography is shown to be a significant factor in controlling the porewater pressures in road-cut slopes in the residual volcanic soils of St Lucia, West Indies. It is shown that this control diminishes as the permeability of the material decreases. This finding is confirmed by stability envelopes in which ‘stable’ and failed slopes are examined as a function of slope topography and material properties.     

The behaviour of iodine and bromine in estuarine surface sediments

The distribution of iodine and bromine was examined in sediments which receive inputs of marine and terrigenous organic matter. The I and Br concentrations are directly related to the content of ‘marine’ organic matter defined using carbon/nitrogen ratios. In the Etive sediments both Br and I may be used as an indicator of ‘marine’ organic matter; Br is of general application as the $\text{Br}\text{C}{}_{\mathrm{mar}}$ ratio (180 × 10^?4) is similar to ratios in other sedimentary environments but the use of I is restricted as the $\text{I}\text{C}{}_{\mathrm{mar}}$ ratio is unlike those in other sediments. Experimental study of iodine sorption clearly shows the importance of decaying marine organic matter and oxygenated conditions in the incorporation of iodine by sediments. This suggests that the mechanism of incorporation of iodine by seston previously proposed is probably an important pathway to sediments. The similarity of Br association with marine organic matter suggests that Br sorption as opposed to residual enrichment may be important for sediment Br accumulation.     

Latest Miocene and Pleistocene ages of faulting, determined by 40Ar/39Ar single-crystal dating of airfall tuff and silicic extrusives of the Erciyes Basin, central Turkey: evidence for intraplate deformation related to the tectonic escape of Anatolia

The Ericiyes Basin is a trans‐tensional basin situated 20 km north of the regional Ecemi? Fault Zone. Recently it has been hypothesized that faulting within the Erciyes Basin links with the Ecemi? Fault Zone further south as part of a regional Central Anatolian Fault Zone. New ⁴⁰Ar/³⁹Ar dating of volcanic and volcaniclastic rocks adjacent to faults, both along the margins and in the centre of the Erciyes Basin, constrains the timing of basin inception and later faulting. Extensional faulting occurred along the eastern and western margins of the basin during the Early Messinian (latest Miocene). Sinistral and minor normal faulting were active along the axis of the basin during the early Pleistocene. These fault timings are similar to those inferred for the Ecemi? Fault Zone further south, and support the hypothesis that faulting within the Erciyes Basin and the Ecemi? Fault Zone are indeed linked.