Mineralogical appraisal and beneficiation tests on some industrial minerals from Zambia

In March 1990, a visit to Zambia was made by D A Briggs of the Mineralogy and Petrology Group on behalf of the British Geological Survey/Overseas Development Administration project "Minerals for Development". The visit, which was described in Technical Report No. WG/90/15R, aimed to establish contact with the Geological Survey Department and other organisations concerned with minerals in Zambia to offer assistance in the field of mineral resource development. This primarily involved discussions with Mr N J Money and Mr J G G Tether, respectively Director and Deputy Director of the Geological Survey . department and their colleagues. The Ministry of Mines and the Mineral Exploration Department (Minex) of the Zambia Industrial and Mining Corporation and other bodies were also involved in the discussions

Improved sperm freezing in the endangered African wild dog (Lycaon pictus) using a two-step dilution TRIS-egg yolk extender containing Equex STM

Development of assisted breeding techniques can aid conservation and management of the endangered African wild dog (Lycaon pictus). Previous attempts to freeze sperm from this species has proven unsuccessful with sperm motility dropping to nearly 0% within 2 h of thawing. The aim of this study was to improve the freezing success of African wild dog sperm by testing two routinely used canine cryopreservation protocols. Sperm was frozen from n=3 captive African wild dog males housed at Albuquerque BioPark (Albuquerque, NM, USA) and Binder Park Zoo (Battle Creek, MI, USA) during the breeding season (Aug-Sept 2014). Freshly collected semen samples were evaluated for volume, colour, pH, motility, viability, morphology, sperm number, acrosome status and DNA integrity. Each sample was split and frozen using two different protocols. Protocol 1: semen was diluted with a Tris-egg yolk extender containing 8% glycerol and 20% egg yolk, and slowly cooled from 37°C to 4°C over 2.5 h. The sample was then loaded into 0.25 mL straws, suspended 4 cm over liquid nitrogen vapour for 10 min, then plunged in liquid nitrogen. Protocol 2: semen was first diluted with a Tris-egg yolk extender containing only 3% glycerol and 20% egg yolk, followed by a second extender (same composition) now containing 7% glycerol and 1% Equex STM, added after the 2.5 h refrigeration period. The freezing procedure was the same as Protocol 1. Straws from both protocols were thawed in a 37ᵒC water bath, but Protocol 2 straws were further diluted by with a thawing solution which that consisted of the initial extender solution without glycerol and egg yolk. Sperm were incubated at 37 ᵒC and motility evaluated at 5 min and every 2 h for 8 h after thawing. Viability, morphology and acrosome integrity was evaluated over 6 h and DNA integrity was evaluated immediately post-thaw. Sperm motility declined significantly for both protocols immediately after thawing (fresh 78.9 ± 2.6%; Protocol 1 24.4 ± 5.0%; Protocol 2 36.7 ± 4.2%; P ≤ 0.05). Motility was significantly higher for Protocol 2 from 2 h after thawing (Protocol 1 1.0 ± 0.8%; Protocol 2 30.8 ± 1.9%; P ≤ 0.05) and sperm remained motile for up to 8 h. Sperm frozen with Protocol 2 also had significantly higher viability (Protocol 1 37.0 ± 5.7%; Protocol 2 65.3 ± 9.9%; P ≤ 0.05) and acrosome integrity (Protocol 1 22.8 ± 8.2%; Protocol 2 69.3 ± 8.8%; P ≤ 0.05) immediately after thawing. There was no difference in the proportion of normal morphology or DNA fragmentation between both protocols. Our results demonstrate that using a two-step dilution with TRIS-egg yolk extender containing Equex STM yields greatly improved post-thaw quality and longevity in African wild dog sperm; making it suitable for use in artificial insemination

The evolution of online teaching and learning in engineering at Deakin University

This paper presents a brief history of the use of online technologies in the support of teaching and learning in the School of Engineering and Technology at Deakin University, Victoria, Australia. It addresses the following topics: flexible engineering programs at Deakin University; computer-based learning in the School of Engineering and Technology; progression from individual efforts to formal, centralized control of the World Wide Web (Web); the costs of information technology; experiences with grant funded development projects; managing the development of online material; student access and equity; and staff development and cultural change. A sustainable online content development model is proposed to carry the School&rsquo;s online initiatives in support of teaching and learning activities into the future.<br /

In situ measurements of near-surface hydraulic conductivity in engineered clay slopes

In situ measurements of near-saturated hydraulic conductivity in fine grained soils have been made at six exemplar UK transport earthwork sites: three embankment and three cutting slopes. This paper reports 143 individual measurements and considers the factors that influence the spatial and temporal variability obtained. The test methods employed produce near-saturated conditions and flow under constant head. Full saturation is probably not achieved due to preferential and by-pass flow occurring in these desiccated soils. For an embankment, hydraulic conductivity was found to vary by five orders of magnitude in the slope near-surface (0 to 0.3 metres depth), decreasing by four orders of magnitude between 0.3 and 1.2 metres depth. This extremely high variability is in part due to seasonal temporal changes controlled by soil moisture content, which can account for up to 1.5 orders of magnitude of this variability. Measurements of hydraulic conductivity at a cutting also indicated a four orders of magnitude range of hydraulic conductivity for the near-surface, with strong depth dependency of a two orders of magnitude decrease from 0.2 to 0.6 metres depth. The main factor controlling the large range is found to be spatial variability in the soil macro structure generated by wetting/drying cycle driven desiccation and roots. The measurements of hydraulic conductivity reported in this paper were undertaken to inform and provide a benchmark for the hydraulic parameters used in numerical models of groundwater flow. This is an influential parameter in simulations incorporating the combined weather/vegetation/infiltration/soil interaction mechanisms that are required to assess the performance and deterioration of earthwork slopes in a changing climate

Real-space local polynomial basis for solid-state electronic-structure calculations: A finite-element approach

We present an approach to solid-state electronic-structure calculations based on the finite-element method. In this method, the basis functions are strictly local, piecewise polynomials. Because the basis is composed of polynomials, the method is completely general and its convergence can be controlled systematically. Because the basis functions are strictly local in real space, the method allows for variable resolution in real space; produces sparse, structured matrices, enabling the effective use of iterative solution methods; and is well suited to parallel implementation. The method thus combines the significant advantages of both real-space-grid and basis-oriented approaches and so promises to be particularly well suited for large, accurate ab initio calculations. We develop the theory of our approach in detail, discuss advantages and disadvantages, and report initial results, including the first fully three-dimensional electronic band structures calculated by the method.Comment: replacement: single spaced, included figures, added journal referenc

Spanning forests and the q-state Potts model in the limit q \to 0

We study the q-state Potts model with nearest-neighbor coupling v=e^{\beta J}-1 in the limit q,v \to 0 with the ratio w = v/q held fixed. Combinatorially, this limit gives rise to the generating polynomial of spanning forests; physically, it provides information about the Potts-model phase diagram in the neighborhood of (q,v) = (0,0). We have studied this model on the square and triangular lattices, using a transfer-matrix approach at both real and complex values of w. For both lattices, we have computed the symbolic transfer matrices for cylindrical strips of widths 2 \le L \le 10, as well as the limiting curves of partition-function zeros in the complex w-plane. For real w, we find two distinct phases separated by a transition point w=w_0, where w_0 = -1/4 (resp. w_0 = -0.1753 \pm 0.0002) for the square (resp. triangular) lattice. For w > w_0 we find a non-critical disordered phase, while for w < w_0 our results are compatible with a massless Berker-Kadanoff phase with conformal charge c = -2 and leading thermal scaling dimension x_{T,1} = 2 (marginal operator). At w = w_0 we find a "first-order critical point": the first derivative of the free energy is discontinuous at w_0, while the correlation length diverges as w \downarrow w_0 (and is infinite at w = w_0). The critical behavior at w = w_0 seems to be the same for both lattices and it differs from that of the Berker-Kadanoff phase: our results suggest that the conformal charge is c = -1, the leading thermal scaling dimension is x_{T,1} = 0, and the critical exponents are \nu = 1/d = 1/2 and \alpha = 1.Comment: 131 pages (LaTeX2e). Includes tex file, three sty files, and 65 Postscript figures. Also included are Mathematica files forests_sq_2-9P.m and forests_tri_2-9P.m. Final journal versio

Integration of fluorescence collection optics with a microfabricated surface electrode ion trap

We have successfully demonstrated an integrated optical system for collecting the fluorescence from a trapped ion. The system, consisting of an array of transmissive, dielectric micro-optics and an optical fiber array, has been intimately incorporated into the ion-trapping chip without negatively impacting trapping performance. Epoxies, vacuum feedthrough, and optical component materials were carefully chosen so that they did not degrade the vacuum environment, and we have demonstrated light detection as well as ion trapping and shuttling behavior comparable to trapping chips without integrated optics, with no modification to the control voltages of the trapping chip.Comment: 14 pages, 12 figure