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Résultats des études menées en Angleterre: détermination de la posologie optimale

- Woodford, R, Haigh, John M, Barry, B W

  • Authors: Woodford, R , Haigh, John M , Barry, B W
  • Date: 1981
  • Language: French
  • Type: Article
  • Identifier: vital:6449 , http://hdl.handle.net/10962/d1006636
  • Description: Les auteurs ont etudie la biodisponibilite et I'activite de formules experimentales et commercialisees de dermocortico'ides en utilisant les essais de vasoconstriction avec et sans occlusion (1, 2, 6, 7, 8, 9). L'application unique de six heures avec lectures multiples a ete largement utilisee dans ce travail et la methodologie en a ete decrite en detail ailleurs (4). Sur la base de ce travail. on a pratique des applications repetees de dermocortico'ides commercialises au Royaume- Uni. en utilisant Ie test du blanchiment de la peau sans occlusion, de maniere a reproduire au plus pres la situation realisee en clinique (3). Ce travail a montre que I'application de cortico'ides trois fois par jour pendant cinq jours aboutissait a une tachyphylaxie considerable de la reponse du blanchiment quelque soit I'activite therapeutique de la formule utilisee. Au bout de deux jours de repos, on a assiste a une recuperation considerable, mais a nouveau une tachyphylaxie aigue s'est installee a la suite d'une nouvelle application triquotidienne.
  • Full Text:
  • Date Issued: 1981

Sampling in the evaluation of ore deposits

- Grant, D E C S

  • Authors: Grant, D E C S
  • Date: 1981 , 2013-03-19
  • Subjects: Ore deposits , Mine valuation , Ores -- Sampling and estimation
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5008 , http://hdl.handle.net/10962/d1005912 , Ore deposits , Mine valuation , Ores -- Sampling and estimation
  • Description: Sampling is an error generating process and these errors should be reduced to a minimum if an accurate ore reserve estimation is to be made from the sample values. Error in sampling can arise from the sampling procedure as well as where and how each sample is taken from the deposit . Sampling procedure involves sample collection, sample reduction and analysis, and the error from each of these three stages has an equal influence on the total error of the process. Error due to sampling procedure should be identified and eliminated at an early stage in the evaluation programme. An ore deposit should be subdivided into sampling strata along geological boundaries, and once these boundaries have been established they should be adhered to for the evaluation programme. The sampling of each stratum depends on the small-scale structures in which the grade is distributed, and this distribution in relation to sample size controls sample variance, sample bias and the volume of influence of each sample. Cluster sampling can be used where an impractically large sample is necessary to reduce sample variance or increase the volume of influence of samples. Sample bias can be reduced by composing a large number of small samples . Sampling patterns should be designed with reference to the volumes of influence of samples, and in favourable geology, geostatistical or statistical techniques can be used to predict the precision of an ore reserve estimation 1n terms of the number of samples taken. Different are deposits have different sampling characteristics and problems which can be directly related to the geology of the mineralization. If geology is disregarded when sampling an are deposit, an evaluation programme cannot claim to give an accurate estimate of the ore reserves .
  • Full Text:
  • Date Issued: 1981

Sanctus

- Goagoses, C., Composer not specified, Dargie, Dave

Schizophrenia and mysticism: a conceptual analysis

- Hammond, Carol Anne

  • Authors: Hammond, Carol Anne
  • Date: 1981
  • Subjects: Schizophrenia , Mysticism
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3129 , http://hdl.handle.net/10962/d1006348 , Schizophrenia , Mysticism
  • Description: From introduction: The aim of this thesis is to explore the "queer relationship'" existing between mysticism and madness as it emerges from psychological writings and to examine and re-evaluate the life of Joan of Arc in terms of the conceptual framework that emerges.
  • Full Text:
  • Date Issued: 1981

Sele Ahom

- St George's Church Choir, Composer Not Specified, Dargie, Dave

Sele Ahom

- Church Choir, Composer Not Specified, Dargie, Dave

Sele Ahom

- St George's Church Choir, Composer Not Specified, Dargie, Dave

Sele Ahom

- Lumko Church Choir, Composer Not Specified, Dargie, Dave

Sele Ahom

- St George's Church Choir, Composer Not Specified, Dargie, Dave

Sele Ahom

- St Gabriel's Catholic Church Choir, Composer Not Specified, Dargie, Dave

Sele Ahom

- St George's Church Choir, Composer not specified, Dargie, Dave

Separation and characterisation of chromium (III) carboxylate solutions

- Bryson, Michael Andrew Walker

  • Authors: Bryson, Michael Andrew Walker
  • Date: 1981
  • Subjects: Chromium
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4416 , http://hdl.handle.net/10962/d1006847
  • Description: From Summary: The complexes present in chromium(III) carboxylate solutions (acetate or formate) were separated using ion exchange chromatography, electrophoresis and gel filtration. Eight cationic species and one non-ionic species with charges from 0 to +3 and nuclearities ranging from mononuclear to quadranuclear were isolated from chromium(III) acetate solutions. Six cationic species with charges from +1 to +3 and nuclearities ranging from mononuclear to trinuclear were isolated from chromium(III) formate solutions. The empirical formulae for these complexes were determined by analytical methods. Infra- red spectroscopy was used to distinguish between monodentate and bidentate bridged carboxylate ligands. An immediate change in the visible spectrum of a complex on its acidification was used as evidence that a terminal hydroxo group was present.
  • Full Text:
  • Date Issued: 1981

Setting of Psalm 23 to music

- Workshop participants, Sithole, Clement, Brother OSB, Dargie, Dave

Sibulela kuThixo

- St George's Church Choir, Composer not specified, Dargie, Dave

Siyabonga

- St George's Church Choir, Composer Not Specified, Dargie, Dave

Siyakholwa

- Eshowe Cathedral Congregation, Composer Not Specified, Dargie, Dave

Siyakholwa

- St George's Church Choir, Composer not specified, Dargie, Dave

Siyambulel' uThixo = We are grateful to the Lord

- Lumko church congregation, Composer not specified, Dargie, Dave

Some aspects of housing economics with reference to the coloured population of South Africa

- Farabi, Sadraddin

Some aspects of the biology of Nassarius kraussianus (Dunker)(Gastropoda : Prosobranchia : Nassariidae), in the Bushman's River estuary, with particular reference to recolonisation after floods

- Palmer, Carolyn Gay

  • Authors: Palmer, Carolyn Gay
  • Date: 1981
  • Subjects: Gastropoda -- South Africa -- Eastern Cape , Estuarine biology -- South Africa -- Eastern Cape , Prosobranchia -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5809 , http://hdl.handle.net/10962/d1006934 , Gastropoda -- South Africa -- Eastern Cape , Estuarine biology -- South Africa -- Eastern Cape , Prosobranchia -- South Africa -- Eastern Cape
  • Description: 1. The development of estuarine research in South Africa has been reviewed, and the present state of knowledge assessed. Little is known about many abundant estuarine species, and a previously unstudied prosobranch Nassarius kraussianus (Dunker), was selected for investigation. 2. The study area, a mudflat on the Bushmans River estuary, was divided into three habitat types: supratidal, intertidal and subtidal, each with a particular substratum and pattern of vegetation cover. The distribution of N. kraussianus is associated with the nature of the substratum and the degree of Zostera capensis Setchell cover. 3. A brief review of pertinent literature indicated the necessity of relating population parameters to environmental conditions. 4. The population biology of N. . kraussianus was investigated, and the size frequencies, sex ratios, and male/female size frequencies were recorded over three distinct periods: pre-flood, post-flood and recovery. 5. The Bushmans River flooded in July and August 1979, and the results of the flood have been described. The most immediate result was a period of low salinity, but the most persistant result was the deposition of silt, which had an important effect on the substratum and the Z. capensis beds. 6. The pre-flood population was characterised by patchy distribution, and by a large number of mature adults in relation to juveniles. Females were generally larger than males, and the sex ratio was 1:1. The presence of juveniles in consistantly low numbers indicated that reproduction may have been continuous, but that intraspecific adult/juvenile competition may have kept juvenile numbers low. 7. The post-flood period was characterised by extreme physical conditions, and the survival of a few adults. Juveniles were completely annihilated, and were absent until a few were spawned by the surviving adults towards the end of 1979 . Sex ratio was biased, and females predominated. 8. The recovery period began abruptly with the arrival of a large number of juveniles in the 2, 3 and 4 mm size classes. Recolonisation coincided with habitat recovery, and reqeneration of the Z. capensis cover. Recolonising juveniles grew quickly, reaching adult size in three months. After that, juveniles were spawned on the mudflat by the new population. During this period the sex ratio did not return to the pre-flood 1:1, but remained female biased. Males and females grew at the same rate over the period measured, but females were consistantly larger, indicating that at some stage female growth may be faster. 9. The recolonising juveniles arrived in a regenerated habitat, at a time when temperatures were high, and conditions for growth probably optimal. If intraspecific competition was a feature of the pre-flood population it would have been elimianted in the recovery phase, by the absence of adults. 10. N. kraussianus is apparently omnivorous and proabably not food limited. However, carrion, a limited resource, may be essential for growth to reproductive maturity. Adults and juveniles may compete for this resource, and any juveniles deprived of access to carrion may be stimulated to leave the parental habitat. 11. N. kraussianus is ovoviviparous, and carries up to 5 egg cases within the uterus. Each triangular egg case contains 1 egg which hatches after approximately 3 weeks, as a free swimming veliger. Yeligers metamorphose, and settle after 4-7 days, assuming a benthic mode of life. Ovoviviparity protects the developing embryo from the rigours of environmental extremes, and ensures that embryos are not swept out to sea . Additionally, veligers have a high probability of settling in the parental habitat. 12. This reproductive strategy has been compared with other prosobranchs, and the evolutionary trends within the Prosobranchia, and particularly the Nassariidae, have been related to their dispersal potential. 13. Developmental strategy is intimately related to recolonisation potential. Ovoviviparity, and the lack of pelagic larvae, did not limit the recolonisation potential of N. kraussianus, and recolonisation was probably effected by post-larval juveniles, which may disperse from neighbouring estuaries and coastal pools, by floating in coastal and tidal currents. Post-larval juveniles have two important advantages over larvae. They are less vulnerable to physical extremes, and they have a sturdy crennellated shell which probably affords them protection from predators. 14. Examples of larval recolonisation in estuarine populations have been reviewed, and the most fundamental conclusion of this work is that recolonisation is an important, and probably widespread, adaptation to estuarine conditions in South Africa.
  • Full Text:
  • Date Issued: 1981
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