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Title not specified

- Church Choir, Martina, OSB, Sister, Dargie, Dave

Kyrie

- Church music workshop participants, Mopete, Poppy, Dargie, Dave

Ubukumkani bam asibobalapha

- Xhosa festival workshop participants, Mbongwe, Peter, Dargie, Dave

Usisiqalo nesiphelo

- Music workshop participants, Composer not specified, Dargie, Dave

Eyang Hle eyang

- Church music workshop participants, Molefe, S. C., Dargie, Dave

Colour vision of the citrus psylla Trioza erytreae (Del Guercio) (Homoptera: Psyllidae) in relation to alightment colour preferences

- Urban, Alan Joseph

  • Authors: Urban, Alan Joseph
  • Date: 1977
  • Subjects: Trioza , Homoptera , Jumping plant-lice , Color vision
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5885 , http://hdl.handle.net/10962/d1013286
  • Description: The colour vision of adult citrus psylla, Trioza erytreae, was investigated in the laboratory using the behavioural parameters: alightment and walking. Light green flushing leaves (under which the nymphs develop) were significantly preferred, visually, to dark green mature leaves for alightment. Diffuse reflectance spectroscopy showed (when expressed in the parameters of human colour vision) that flush has a very slightly longer dominant wavelength, and roughly double the reflectance and purity. Alightrnent frequency correlated almost equally well with "purity" (as noted by Moericke, 1952 et seq., in "yellow-sensitive" aphids) as with the aphidological colour parameter "long/short ratio" developed by Kennedy et al. (1961). Elucidation of the mechanism underlying the citrus psylla's alightment colour preference was initially attempted with a printed spectrum and several paint series of measured spectral characteristics. It was clear that T.erytreae belongs to the "yellow-sensitive" group of Homoptera, but it was impossible to distinguish which pararneter(s) of colour the psyllids were responding to. Phototactic (walking) response to the individual parameters of colour was therefore measured using a monochromator. The phototactic action spectrum (against wavelength) was tri-modal, with peaks in the yellow-green (YG), blue (B), and ultra= violet (UV). Rate of phototaxis was not influenced by bandwidth (roughly equivalent to purity), but was proportional to intensity (roughly equivalent to reflectance). To investigate the influence of the above three wavelength regions on alightment, use was made of a very simple flight chamber incorporating a target of coloured light. Yellow-green and UV light both independently stimulated alightment . Their effect was additive. Different thresholds indicated distinct YG and UV receptor systems. Blue light alone did not stimulate alightment, and was strongly alightment-inhibitory in combination both with YG and with UV light. On the basis of the above physiological/behavioural findings, a new alightment formula was drawn up for describing the hamopteran's apparent manner of alightment determining integration of surface reflectance. The flush preference and alightment distributions on the series of artificial surfaces were found to correlate slightly more accurately, on average, as well as more consistently, with the new formula than with previously-available colour parameters. These findings are placed in perspective to the literature, and their possible economic relevance is discussed.
  • Full Text:
  • Date Issued: 1977

Masibulisane egameni likaKrestu

- Xhosa music festival participants, Group Composition, Dargie, Dave

Umhle jenge nyanga uMaria

- Xhosa festival workshop participants, Martina, OSB., Sister, Dargie, Dave

Umalusi

- Workshop participants, Malema, S. T., Moyo, R., Dargie, Dave

Rhodes University Graduation Ceremony 1977

- Rhodes University

  • Authors: Rhodes University
  • Date: 1977
  • Subjects: MacKenzie, Ian
  • Language: English
  • Type: text
  • Identifier: vital:8111 , http://hdl.handle.net/10962/d1004567 , MacKenzie, Ian
  • Description: Rhodes University Graduation Ceremonies on Friday, 1st April, 1977 at 8 p.m. [and] on Saturday, 2nd April, 1977 at 10:30 a.m.in the 1820 Settlers National Monument. , The Order for the Installation of Ian MacKenzie as Chancellor of Rhodes University within the Great Hall on Thursday 31 March 1977 at 8:15 p.m.
  • Full Text:
  • Date Issued: 1977

Siyambulel' uThixo

- Xhosa festival workshop participants, Lamla. Father, Dargie, Dave

Rumela Moyo

- Church Choir, Composer not Specified, Dargie, Dave

Wena o mopriesta

- Church music workshop participants, Molefe, S. C., Dargie, Dave

Batshengisenin' uthando

- Music workshop participants, Composer not specified, Dargie, Dave

Ba nencenba kuthi

- Xhosa music festival participants, Mpotulo, Lambert, Dargie, Dave

Our Father

- Church music workshop participants, Suping, T. W., Dargie, Dave

Fishes of the family Pseudochromidae (Perciformes) in the Western Indian Ocean (with plates 1-5); and a note on Anisochromis Kenya

- Lubbock, Roger, Smith, Margaret Mary

  • Authors: Lubbock, Roger , Smith, Margaret Mary
  • Date: 1977
  • Subjects: Pseudochromidae -- Indian Ocean , Marine fishes -- Indian Ocean
  • Language: English
  • Type: Text
  • Identifier: vital:14987 , http://hdl.handle.net/10962/d1018955 , Ichthyological Bulletin of the J.L.B. Smith Institute of Ichthyology; No. 35
  • Description: An account is given of pseudochromid fishes from the western Indian Ocean. Seven species of Pseudochromis (four of which are new) and six species of Chlidichthys (three of which are new) are recorded and described, with details of ecology. Keys are provided. , This note lists specimens caught to date and increase in distribution of Anisochromis kenyae. Two colour illustrations demonstrate the sexual dichromatism. , Rhodes University Libraries (Digitisation)
  • Full Text:
  • Date Issued: 1977

Title not specified

- Performer not specified, Composer not specified, Dargie, Dave

Umlindo wesililo

- Music workshop participants, Dlungwane, Pious., Father, Dargie, Dave

Lona bo mme le bo ntate

- Vosloorus Choir, Kathaka, S., Dargie, Dave

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