An anatomical investigation of jointed cactus (Opuntia aurantiaca, Lindley) with germination tests, and observations on the movements of the stomata

From Introduction: In 1934 the Government started an active campaign on the eradiction of Jointed Cactus. This plant was causing considerable damage to the farms and commonages of the Eastern Province, and was spreading at an alarming rate. The Officer in Charge of eradication, Mr E. du Toit, was stationed at Grahamstown which is fairly centrally situated in the infested area. In 1935 Dr A. Leemann of the Division of Plant Industry made his headquarters at Rhodes University College

A submillimetre survey of the star-formation history of radio galaxies

We present the results of the first major systematic submillimetre survey of radio galaxies spanning the redshift range 1 < z < 5. The primary aim of this work is to elucidate the star-formation history of this sub-class of elliptical galaxies by tracing the cosmological evolution of dust mass. Using SCUBA on the JCMT we have obtained 850-micron photometry of 47 radio galaxies to a consistent rms depth of 1 mJy, and have detected dust emission in 14 cases. The radio galaxy targets have been selected from a series of low-frequency radio surveys of increasing depth (3CRR, 6CE, etc), in order to allow us to separate the effects of increasing redshift and increasing radio power on submillimetre luminosity. Although the dynamic range of our study is inevitably small, we find clear evidence that the typical submillimetre luminosity (and hence dust mass) of a powerful radio galaxy is a strongly increasing function of redshift; the detection rate rises from 15 per cent at z 2.5, and the average submillimetre luminosity rises as (1+z)^3 out to z~4. Moreover our extensive sample allows us to argue that this behaviour is not driven by underlying correlations with other radio galaxy properties such as radio power, radio spectral index, or radio source size/age. Although radio selection may introduce other more subtle biases, the redshift distribution of our detected objects is in fact consistent with the most recent estimates of the redshift distribution of comparably bright submillimetre sources discovered in blank field surveys. The evolution of submillimetre luminosity found here for radio galaxies may thus be representative of massive ellipticals in general.Comment: 31 pages - 10 figures in main text, 3 pages of figures in appendix. This revised version has been re-structured, but the analysis and conclusions have not changed. Accepted for publication in MNRA

The solvent extraction of nitrosylruthenium by trilaurylamine in nitrate systems : summary report for the period July 1, 1960 to March 31, 1962

"June 1, 1962."Also issued as an Sc. D. thesis, Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1962Summary report; July 1, 1960 to March 31, 1962Work performed under subcontract no. 1327 under contract no. W-7405-Eng-26 with Union Carbide Nuclear Corporation, Oak Ridge, Tennesse

Equilibrium extraction characteristics of alkyl amines and nuclear fuel metals in nitrate systems: progress report for the period January 1- September 30, 1960 : progress report VII

"November 1, 1960."Includes bibliographical references (pages 20-21)Progress report no. VII; January 1 - September 30, 1960Work performed under subcontract no. 1327 under contract no. W -7405 - Eng - 26 with Union Carbide Nuclear Corporation Oak Ridge, Tennesse

Equilibrium extraction characteristics of alkyl amines and nuclear fuel metals in nitrate systems: progress report for the period July 1 - December 31, 1961 : progress report X

"February 15, 1962."Includes bibliographical references (page 62)Progress report no. 10; July 1 to December 31, 1961Work performed under subcontract no. 1327 under contract no. W -7405 - Eng - 26 with Union Carbide Nuclear Corporation Oak Ridge, Tennesse

The SCUBA 8-mJy survey - I: Sub-millimetre maps, sources and number counts

We present maps, source lists, and number counts from the largest, unbiassed, extragalactic sub-mm survey so far undertaken with the SCUBA camera on the JCMT. Our maps cover 260 sq. arcmin, to a noise level S(850)=2.5 mJy/beam. We have reduced the data using both SURF, and our own pipeline which produces zero-footprint maps and noise images. The uncorrelated noise maps produced by the latter approach have allowed application of a maximum-likelihood method to measure the statistical significance of each peak, leading to properly quantified flux-density errors for all potential sources. We detect 19 sources with S/N > 4, 38 with S/N > 3.5, and 72 with S/N > 3. To assess completeness and the impact of source confusion we have applied our source extraction algorithm to a series of simulated images. The result is a new estimate of the sub-mm source counts in the flux-density range S(850)=5-15mJy, which we compare with other estimates, and with model predictions. Our estimate of the cumulative source count at S(850) > 8 mJy is 320 (+80,-100) per square degree. Assuming that the majority of sources have z > 1.5, the co-moving number density of high-z galaxies forming stars at a rate >1000 solar masses per year is 10^-5 per Mpc^3, with only a weak dependence on the precise redshift distribution. This number density corresponds to that of massive ellipticals with L > 3-4 L* at low redshift and is also the same as the co-moving number density of comparably massive, passively-evolving objects in the redshift band 1<z<2 inferred from recent surveys of extremely red objects. Thus the bright sub-mm sources can plausibly account for the formation of all present-day massive ellipticals. Improved z constraints, and a proper measurement of sub-mm clustering can refine or refute this picture.Comment: Minor revisions. 27 pages, 13 figures. Higher resolution versions of Figs 5,6,7 and 8 are available from the autho

40Ar/39Ar phlogopite geochronology of lamprophyre dykes in Cornwall, UK: new age constraints on Early Permian post-collisional magmatism in the Rhenohercynian Zone, SW England

Journal of the Geological Society (2015), http://jgs.lyellcollection.org/content/early/2015/06/03/jgs2014-151. Copyright © Geological Society of London 2015The spatial and temporal association of post-collisional granites and lamprophyre dykes is a common but enigmatic relationship in many orogenic belts, including the Variscan orogenic belt of SW England. The geology of SW England has long been interpreted to reflect orogenic processes associated with the closure of the Rheic Ocean and the formation of Pangaea. The SW England peninsula is composed largely of Early Devonian to Carboniferous volcano-sedimentary successions deposited in synrift and subsequent syncollisional basins that underwent deformation and low-grade regional metamorphism during the Variscan orogeny. Voluminous Early Permian granitic magmatism (Cornubian Batholith) is considered to be broadly coeval with the emplacement of lamprophyric dykes and lamprophyric and basaltic lava flows, largely on the basis of geochronological data from lamprophyric lavas in Devon. Although published geochronological data for Cornish lamprophyre dykes are consistent with this interpretation, these data are limited largely to imprecise K–Ar whole-rock and biotite analyses, hindering the understanding of the processes responsible for their genesis and their relationship to granitic magmatism and regional Variscan tectonics. 40Ar/39Ar geochronological data for four previously undated lamprophyre dykes from Cornwall, combined with published data, suggest that lamprophyre magmatism occurred between c. 293.6 and c. 285.4 Ma, supporting previous inferences that their emplacement was coeval with the Cornubian Batholith. These data provide insights into (1) the relative timing between the lamprophyres and basalts, the Cornubian batholith and post-collisional magmatism elsewhere in the European Variscides, and (2) the post-collisional processes responsible for the generation and emplacement of lamprophyres, basalts and granitoids.NSERC (Canada) Discovery grant